Geology and recognition criteria for sandstone uranium deposits in mixed fluvial-shallow marine sedimentary sequences, South Texas. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, S.S.; Smith, R.B.

1981-01-01

Uranium deposits in the South Texas Uranium Region are classical roll-type deposits that formed at the margin of tongues of altered sandstone by the encroachment of oxidizing, uraniferous solutions into reduced aquifers containing pyrite and, in a few cases, carbonaceous plant material. Many of the uranium deposits in South Texas are dissimilar from the roll fronts of the Wyoming basins. The host sands for many of the deposits contain essentially no carbonaceous plant material, only abundant disseminated pyrite. Many of the deposits do not occur at the margin of altered (ferric oxide-bearing) sandstone tongues but rather occur entirely within reduced,more » pyurite-bearing sandstone. The abundance of pyrite within the sands probably reflects the introduction of H/sub 2/S up along faults from hydrocarbon accumulations at depth. Such introductions before ore formation prepared the sands for roll-front development, whereas post-ore introductions produced re-reduction of portions of the altered tongue, leaving the deposit suspended in reduced sandstone. Evidence from three deposits suggests that ore formation was not accompanied by the introduction of significant amounts of H/sub 2/S.« less

Variations in the uranium isotopic compositions of uranium ores from different types of uranium deposits

NASA Astrophysics Data System (ADS)

Uvarova, Yulia A.; Kyser, T. Kurt; Geagea, Majdi Lahd; Chipley, Don

2014-12-01

Variations in 238U/235U and 234U/238U ratios were measured in uranium minerals from a spectrum of uranium deposit types, as well as diagenetic phosphates in uranium-rich basins and peraluminous rhyolites and associated autunite mineralisation from Macusani Meseta, Peru. Mean δ238U values of uranium minerals relative to NBL CRM 112-A are 0.02‰ for metasomatic deposits, 0.16‰ for intrusive, 0.18‰ for calcrete, 0.18‰ for volcanic, 0.29‰ for quartz-pebble conglomerate, 0.29‰ for sandstone-hosted, 0.44‰ for unconformity-type, and 0.56‰ for vein, with a total range in δ238U values from -0.30‰ to 1.52‰. Uranium mineralisation associated with igneous systems, including low-temperature calcretes that are sourced from U-rich minerals in igneous systems, have low δ238U values of ca. 0.1‰, near those of their igneous sources, whereas uranium minerals in basin-hosted deposits have higher and more variable values. High-grade unconformity-related deposits have δ238U values around 0.2‰, whereas lower grade unconformity-type deposits in the Athabasca, Kombolgie and Otish basins have higher δ238U values. The δ234U values for most samples are around 0‰, in secular equilibrium, but some samples have δ234U values much lower or higher than 0‰ associated with addition or removal of 234U during the past 2.5 Ma. These δ238U and δ234U values suggest that there are at least two different mechanisms responsible for 238U/235U and 234U/238U variations. The 234U/238U disequilibria ratios indicate recent fluid interaction with the uranium minerals and preferential migration of 234U. Fractionation between 235U and 238U is a result of nuclear-field effects with enrichment of 238U in the reduced insoluble species (mostly UO2) and 235U in oxidised mobile species as uranyl ion, UO22+, and its complexes. Therefore, isotopic fractionation effects should be reflected in 238U/235U ratios in uranium ore minerals formed either by reduction of uranium to UO2 or chemical precipitation in the form of U6+ minerals. The δ238U values of uranium ore minerals from a variety of deposits are controlled by the isotopic signature of the uranium source, the efficiency of uranium reduction in the case of UO2 systems, and the degree to which uranium was previously removed from the fluid, with less influence from temperature of ore formation and later alteration of the ore. Uranium isotopes are potentially superb tracers of redox in natural systems.

Geology and ore deposits of the Section 23 Mine, Ambrosia Lake District, New Mexico

USGS Publications Warehouse

Granger, H.C.; Santos, E.S.

1982-01-01

The section 23 mine is one of about 18 large uranium mines opened in sandstones of the fluvial Westwater Canyon Member of the Jurassic Morrison Formation in the Ambrosia Lake mining district during the early 1960s. The Ambrosia Lake district is one of several mining districts within the Grants mineral belt, an elongate zone containing many uranium deposits along the southern flank of the San Juan basin. Two distinct types of ore occur in the mine. Primary ore occurs as peneconcordant layers of uranium-rich authigenic organic matter that impregnates parts of the reduced sandstone host rocks and which are typically elongate in an east-southeast direction subparallel both to the sedimentary trends and to the present-day regional strike of the strata. These are called prefault or trend ores because of their early genesis and their elongation and alinement. A second type of ore in the mine is referred to as postfault, stacked, or redistributed ore. Its genesis was similar to that of the roll-type deposits in Tertiary rocks of Wyoming and Texas. Oxidation, related to the development of a large tongue of oxidized rock extending from Gallup to Ambrosia Lake, destroyed much of the primary ore and redistributed it as massive accumulations of lower grade ores bordering the redox interface at the edge of the tongue. Host rocks in the southern half of sec. 23 (T. 14 N., R. 10 W.) are oxidized and contain only remnants of the original, tabular, organic-rich ore. Thick bodies of roll-type ore are distributed along the leading edge of the oxidized zone, and pristine primary ore is found only near the north edge of the section. Organic matter in the primary ore was derived from humic acids that precipitated in the pores of the sandstones and fixed uranium as both coffinite and urano-organic compounds. Vanadium, molybdenum, and selenium are also associated with the ore. The secondary or roll-type ores are essentially free of organic carbon and contain uranium both as coffinite and uraninite. They also contain vanadium and selenium but are virtually devoid of molybdenum. Although much has been learned about these deposits since the time this study was conducted, in 1966, a great deal more study will by required to completely elucidate their geologic history.

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE PAGES

Balboni, Enrica; Jones, Nina; Spano, Tyler; ...

2016-08-31

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Jones, Nina; Spano, Tyler

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Application of remote sensor data to geologic analysis of the Bonanza test site Colorado

NASA Technical Reports Server (NTRS)

Lee, K. (Compiler)

1975-01-01

Selected samples of anomalous surface features commonly associated with the various types of uranium deposits are presented and recommendations for sensor applications are given. The features studied include: epigenetic uranium ore roll type; precambrian basal conglomerate type; vein-type uranium deposits; pipe-structure or diatreme deposits; evaporitic uranium deposits. The hydrogeology of the Mosquito Range and the San Luis Valley is also examined.

The role of the thermal convection of fluids in the formation of unconformity-type uranium deposits: the Athabasca Basin, Canada

NASA Astrophysics Data System (ADS)

Pek, A. A.; Malkovsky, V. I.

2017-05-01

In the global production of uranium, 18% belong to the unconformity-type Canadian deposits localized in the Athabasca Basin. These deposits, which are unique in terms of their ore quality, were primarily studied by Canadian and French scientists. They have elaborated the diagenetic-hydrothermal hypothesis of ore formation, which suggests that (1) the deposits were formed within a sedimentary basin near an unconformity surface dividing the folded Archean-Proterozoic metamorphic basement and a gently dipping sedimentary cover, which is not affected by metamorphism; (2) the spatial accommodation of the deposits is controlled by the rejuvenated faults in the basement at their exit into the overlying sedimentary sequence; the ore bodies are localized above and below the unconformity surface; (3) the occurrence of graphite-bearing rocks is an important factor in controlling the local structural mineralization; (4) the ore bodies are the products of uranium precipitation on a reducing barrier. The mechanism that drives the circulation of ore-forming hydrothermal solutions has remained one of the main unclear questions in the general genetic concept. The ore was deposited above the surface of the unconformity due to the upflow discharge of the solution from the fault zones into the overlying conglomerate and sandstone. The ore formation below this surface is a result of the downflow migration of the solutions along the fault zones from sandstone into the basement rocks. A thermal convective system with the conjugated convection cells in the basement and sedimentary fill of the basin may be a possible explanation of why the hydrotherms circulate in the opposite directions. The results of our computations in the model setting of the free thermal convection of fluids are consistent with the conceptual reasoning about the conditions of the formation of unique uranium deposits in the Athabasca Basin. The calculated rates of the focused solution circulation through the fault zones in the upflow and downflow branches of a convection cell allow us to evaluate the time of ore formation up to the first hundreds of thousands years.

Exploration for uranium deposits in the Spring Creek Mesa area, Montrose County, Colorado

USGS Publications Warehouse

Roach, Carl Houston

1954-01-01

4. The “ore-bearing sandstone” in the vicinity of relatively unoxidized ore deposits commonly contains sparse to abundant disseminated pyrite. In the vicinity of oxidized deposits it commonly contains abundant limonite spots and widespread limonite staining.

Extraction of reduced alteration information based on Aster data: a case study of the Bashibulake uranium ore district

NASA Astrophysics Data System (ADS)

Ye, Fa-wang; Liu, De-chang

2008-12-01

Practices of sandstone-type uranium exploration in recent years in China indicate that the uranium mineralization alteration information is of great importance for selecting a new uranium target or prospecting in outer area of the known uranium ore district. Taking a case study of BASHIBULAKE uranium ore district, this paper mainly presents the technical minds and methods of extracting the reduced alteration information by oil and gas in BASHIBULAKE ore district using ASTER data. First, the regional geological setting and study status in BASHIBULAKE uranium ore district are introduced in brief. Then, the spectral characteristics of altered sandstone and un-altered sandstone in BASHIBULAKE ore district are analyzed deeply. Based on the spectral analysis, two technical minds to extract the remote sensing reduced alteration information are proposed, and the un-mixing method is introduced to process ASTER data to extract the reduced alteration information in BASHIBULAKE ore district. From the enhanced images, three remote sensing anomaly zones are discovered, and their geological and prospecting significances are further made sure by taking the advantages of multi-bands in SWIR of ASTER data. Finally, the distribution and intensity of the reduced alteration information in Cretaceous system and its relationship with the genesis of uranium deposit are discussed, the specific suggestions for uranium prospecting orientation in outer of BASHIBULAKE ore district are also proposed.

Restructuring the Uranium Mining Industry in Romania: Actual Situation and Prospects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Georgescu, P.D.; Petrescu, S.T.; Iuhas, T.F.

2002-07-01

Uranium prospecting in Romania has started some 50 years ago, when a bilateral agreement between Romania and the former Soviet Union had been concluded and a joint Romanian-Soviet enterprise was created. The production started in 1952 by the opening of some deposits from western Transylvania (Bihor and Ciudanovita). From 1962 the production has continued only with Romanian participation on the ore deposit Avram Iancu and from 1985 on the deposits from Eastern Carpathians (Crucea and Botusana). Starting with 1978 the extracted ores have been completely processed in the Uranium Ore Processing Plant from Feldioara, Brasov. Complying with the initial stipulationsmore » of the Nuclear National Program launched at the beginning of the 1980's, the construction of a nuclear power station in Cernavoda has started in Romania, using natural uranium and heavy water (CANDU type), having five units of 650 MW installed capacity. After 1989 this initial Nuclear National Program was revised and the construction of the first unit (number 1) was finalized and put in operation in 1996. In 2001 the works at the unit number 2 were resumed, having the year 2005 as the scheduled activating date. The future of the other 3 units, being in different construction phases, hasn't been clearly decided. Taking into consideration the exhaustion degree of some ore deposits and from the prospect of exploiting other ore deposits, the uranium industry will be subject of an ample restructuring process. This process includes workings of modernization of the mines in operation and of the processing plant, increasing the profitableness, lowering of the production costs by closing out and ecological rehabilitation of some areas affected by mining works and even new openings of some uraniferous exploitations. This paper presents the actual situation and the prospects of uranium mining industry on the base of some new technical and economical strategic concepts in accordance with the actual Romanian Program for Nuclear Energetics. (authors)« less

Reconnaissance for radioactive materials in northeastern United States during 1952

USGS Publications Warehouse

McKeown, Francis A.; Klemic, Harry

1953-01-01

Reconnaissance for radioactive materials was made in parts of Maine, New York, New Jersey, and Pennsylvania. The primary objective was to examine the iron ore deposits and associated rocks in the Adirondack Mountains of New York and the Highlands of New Jersey. In addition, several deposits known or reported to contain radioactive minerals were examined to delimit their extent. Most of the deposits examined are not significant as possible sources of radioactive elements and the data pertaining to them are summarized in table form. Deposits that do warrant more description than can be given in table form are: Benson Mines, St. Lawrence County, N. Y.; Rutgers mine, Clinton County, N. Y.; Mineville Mines, Essex County, N. Y.l Canfield phosphate mine, Morris County, N. J.; Mullgan quarry, Hunterdon County, N. J.; and the Chestnut Hill-Marble Mountain area, Pennsylvania and New Jersey. The Old Bed in the Mineville district is the only deposit that may be economically significant. Apatite from Old Bed ore contains as much as 4.9 percent total rare earth. 0.04 percent thorium, and 0.018 percent uranium. Magnetite ore at the Rutgers mine contains radioactive zircon and apatite. Radioactivity measurements of outcrops and dump material show that the ore contains from 0.005 to 0.010 percent equivalent uranium. One sample of lean magnetite ore contains 0.006 percent equivalent uranium. Garnet-rich zones in the Benson Mines magnetite deposit contain as much as 0.017 equivalent uranium. Most of the rock and ore, however, contains about 0.005 percent equivalent uranium. Available data indicate that the garnet-rich zones are enriched in radioactive allanite. A shear zone in the Kittatinny limestone of Cambrian age at the Mulligan quarry contains uraniferous material. Radioactivity anomalies elsewhere in the quarry and in adjacent fields indicate that there may be other uraniferous shear zones. Assays of samples and measurements of outcrop radioactivity indicate that the uranium content of these zones is low; samples contain from 0.008 to 0.068 percent equivalent uranium. The anomalies, however, may indicate greater concentrations of uranium below surficial leached zones. The Chestnut Hill-Marble Mountain area contains radioactivity anomalies for about 2 miles along the strike of the contact of pre-Cambrian Pickering gneiss and Franklin limestone formations. In places this contact is injected with pegmatite, which probably was the source of the radioelements. The most favorable area for further study is at Marble Mountain, where a nearly continuous anomaly extends for about 1500 feet. Samples from part of this area contain as much as 0.044 percent equivalent uranium and 0.005 percent uranium. Radioactive hematite and florencite, in which thorium may have substituted for cerium, are the only radioactive minerals observed in the Marble Mountain area.

Summary of the mineralogy of the Colorado Plateau uranium ores

USGS Publications Warehouse

Weeks, Alice D.; Coleman, Robert Griffin; Thompson, Mary E.

1956-01-01

In the Colorado Plateau uranium has been produced chiefly from very shallow mines in carnotite ores (oxidized vanadiferous uranium ores) until recent deeper mining penetrated black unoxidized ores in water-saturated rocks and extensive exploration has discovered many deposits of low to nonvanadiferous ores. The uranium ores include a wide range from highly vanadiferous and from as much as one percent to a trace of copper, and contain a small amount of iron and traces of lead, zinc, molybdenum, cobalt, nickel, silver, manganese, and other metals. Recent investigation indicates that the carnotite ores have been derived by progressive oxidation of primary (unoxidized) black ores that contain low-valent uranium and vanadium oxides and silicates. The uranium minerals, uraninite and coffinite, are associated with coalified wood or other carbonaceous material. The vanadium minerals, chiefly montroseite, roscoelite, and other vanadium silicates, occur in the interstices of the sandstone and in siltstone and clay pellets as well as associated with fossil wood. Calcite, dolomite, barite and minor amounts of sulfides, arsenides, and selenides occur in the unoxidized ore. Partially oxidized vanadiferous ore is blue black, purplish brown, or greenish black in contrast to the black or dark gray unoxidized ore. Vanadium combines with uranium to form rauvite. The excess vanadium is present in corvusite, fernandinite, melanovanadite and many other quadrivalent and quinquevalent vanadium minerals as well as in vanadium silicates. Pyrite and part or all of the calcite are replaced by iron oxides and gypsum. In oxidized vanadiferous uranium ores the uranium is fixed in the relatively insoluble minerals carnotite and tyuyamunite, and the excess vanadium commonly combines with one or more of the following: calcium, sodium, potassium, magnesium, aluminum, iron, copper, manganese, or barium, or rarely it forms the hydrated pentoxide. The relatively stable vanadium silicates are little affected by oxidation. The unoxidized nonvanadiferous ores contain uraninite and coffinite in close association with coalified wood and iron and copper sulfides, and traces of many other sulfides, arsenides and selenides. The oxidized nonvanadiferous ores differ from the vanadiferous ores because, in the absence of vanadium to complex the uranium, a great variety of secondary yellow and greenish-yellow uranyl minerals are formed. The uranyl sulfates and carbonates are more common than the oxides, phosphates, arsenates, and silicates. Because the sulfates and carbonates are much less stable that carnotite, the oxidized nonvanadiferous ores occure only as halos around cores of unoxidized ore and do not form large oxidized deposits close to the surface of the ground as carnotite ores. Oxidation has taken place since the lowering of the water table in the present erosion cycle. Because of local structures and the highly lenticular character of the fluviatile host rocks perched water tables and water-saturated lenses of sandstone are common high above the regional water table. Unoxidized ore has been preserved in these water-saturated rocks and the boundary between oxidized and unoxidized ore is very irregular.

Geology of the Shinarump No. 1 uranium mine, Seven Mile Canyon area, Grand County, Utah

USGS Publications Warehouse

Finch, Warren Irvin

1954-01-01

The geology of the Shinarump No. 1 uranium mine, located about 12 miles northwest of Moab, Utah, in the Seven Mile Canyon area, Grand County, Utah, was studied to determine the habits, ore controls, and possible origin of the deposit. Rocks of Permian, Triassic, and Jurassic age crop out in the area mapped, and uranium deposits are found in three zones in the lower 25 feet of the Chinle formation of Late Triassic age. The Shinarump No. 1 mine, which is in the lowermost zone, is located on the west flank of the Moab anticline near the Moab fault. The Shinarump No. 1 uranium deposit consists of discontinuous lenticular layers of mineralized rock, irregular in outline, that, in general, follow the bedding. Ore minerals, mainly uraninite, impregnate the rock. High-grade ore seams of uraninite and chalcocite occur along bedding planes. Uraninite formed later than, or simultaneous with, most sulfides, and the chalcocite may be of two ages, with some being later than uraninite. Uraninite and chalcocite are concentrated in the more poorly sorted parts of siltstones. In the Seven Mile Canyon area guides to ore inferred from the study of the Shinarump No. 1 deposit are the presence of bleached siltstone, carbonaceous matter, and copper sulfides. Results of spectrographic analysis indicate that the mineralizing solutions contained important amounts of barium, vanadium, uranium, and copper, as well as lesser amounts of strontium, chromium, boron, yttrium, lead, and zinc. The origin of the Shinarump No. 1 deposit is thought to be hydrothermal.

Chemical Equilibrium of the Dissolved Uranium in Groundwaters From a Spanish Uranium-Ore Deposit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garralon, Antonio; Gomez, Paloma; Turrero, Maria Jesus

2007-07-01

The main objectives of this work are to determine the hydrogeochemical evolution of an uranium ore and identify the main water/rock interaction processes that control the dissolved uranium content. The Mina Fe uranium-ore deposit is the most important and biggest mine worked in Spain. Sageras area is located at the north part of the Mina Fe, over the same ore deposit. The uranium deposit was not mined in Sageras and was only perturbed by the exploration activities performed 20 years ago. The studied area is located 10 Km northeast of Ciudad Rodrigo (Salamanca) at an altitude over 650 m.a.s.l. Themore » uranium mineralization is related to faults affecting the metasediments of the Upper Proterozoic to Lower Cambrian schist-graywacke complex (CEG), located in the Centro-Iberian Zone of the Hesperian Massif . The primary uranium minerals are uraninite and coffinite but numerous secondary uranium minerals have been formed as a result of the weathering processes: yellow gummite, autunite, meta-autunite, torbernite, saleeite, uranotile, ianthinite and uranopilite. The water flow at regional scale is controlled by the topography. Recharge takes place mainly in the surrounding mountains (Sierra Pena de Francia) and discharge at fluvial courses, mainly Agueda and Yeltes rivers, boundaries S-NW and NE of the area, respectively. Deep flows (lower than 100 m depth) should be upwards due to the river vicinity, with flow directions towards the W, NW or N. In Sageras-Mina Fe there are more than 100 boreholes drilled to investigate the mineral resources of the deposit. 35 boreholes were selected in order to analyze the chemical composition of groundwaters based on their depth and situation around the uranium ore. Groundwater samples come from 50 to 150 m depth. The waters are classified as calcium-bicarbonate type waters, with a redox potential that indicates they are slightly reduced (values vary between 50 to -350 mV). The TOC varies between <0.1 and 4.0 mgC/L and the dissolved uranium has a maximum value of 7.7 mg/L. According the analytical data of dissolved uranium, the mineral closest to equilibrium seems to be UO{sub 2}(am). The tritium contents in the groundwaters vary between 1.5 and 7.3 T.U. Considering that the mean value of tritium in rainwater from the studied area has a value of 4 T.U., it can be concluded that the residence times of the groundwaters are relatively short, not longer than 50 years in the oldest case. (authors)« less

Sandstone type uranium deposits in the Ordos Basin, Northwest China: A case study and an overview

NASA Astrophysics Data System (ADS)

Akhtar, Shamim; Yang, Xiaoyong; Pirajno, Franco

2017-09-01

This paper provides a comprehensive review on studies of sandstone type uranium deposits in the Ordos Basin, Northwest China. As the second largest sedimentary basin, the Ordos Basin has great potential for targeting sandstone type U mineralization. The newly found and explored Dongsheng and Diantou sandstone type uranium deposits are hosted in the Middle Jurassic Zhilou Formation. A large number of investigations have been conducted to trace the source rock compositions and relationship between lithic subarkose sandstone host rock and uranium mineralization. An optical microscopy study reveals two types of alteration associated with the U mineralization: chloritization and sericitization. Some unusual mineral structures, with compositional similarity to coffinite, have been identified in a secondary pyrite by SEM These mineral phases are proposed to be of bacterial origin, following high resolution mapping of uranium minerals and trace element determinations in situ. Moreover, geochemical studies of REE and trace elements constrained the mechanism of uranium enrichment, displaying LREE enrichment relative to HREE. Trace elements such as Pb, Mo and Ba have a direct relationship with uranium enrichment and can be used as index for mineralization. The source of uranium ore forming fluids and related geological processes have been studied using H, O and C isotope systematics of fluid inclusions in quartz veins and the calcite cement of sandstone rocks hosting U mineralization. Both H and O isotopic compositions of fluid inclusions reveal that ore forming fluids are a mixture of meteoric water and magmatic water. The C and S isotopes of the cementing material of sandstone suggest organic origin and bacterial sulfate reduction (BSR), providing an important clue for U mineralization. Discussion of the ore genesis shows that the greenish gray sandstone plays a crucial role during processes leading to uranium mineralization. Consequently, an oxidation-reduction model for sandstone-type uranium deposit is proposed, which can elucidate the source of uranium in the deposits of the Ordos Basin, based on the role of organic materials and sulfate reducing bacteria. We discuss the mechanism of uranium deposition responsible for the genesis of these large sandstone type uranium deposits in this unique sedimentary basin.

Geological and geochemical aspects of uranium deposits: a selected, annotated bibliography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, J.M.; Brock, M.L.; Garland, P.A.

1978-06-01

A compilation of 490 references is presented which is the second in a series compiled from the National Uranium Resource Evaluation (NURE) Bibliographic Data Base. This data base is one of six created by the Ecological Sciences Information Center, Oak Ridge National Laboratory, for the Grand Junction Office of the Department of Energy. Major emphasis for this volume has been placed on uranium geology, encompassing deposition, genesis of ore deposits, and ore controls; and prospecting techniques, including geochemistry and aerial reconnaissance. The following indexes are provided to aid the user in locating references of interest: author, geographic location, quadrangel name,more » geoformational feature, taxonomic name, and keyword.« less

The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

USGS Publications Warehouse

Van Gosen, Bradley S.; Hall, Susan M.

2017-12-18

This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments.In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U3O8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U3O8.The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age.Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234U/238U activity ratios indicate two separate, distinct fluid sources.

The importance of dissolved free oxygen during formation of sandstone-type uranium deposits

USGS Publications Warehouse

Granger, Harry Clifford; Warren, C.G.

1979-01-01

One factor which distinguishes t, he genesis of roll-type uranium deposits from the Uravan Mineral Belt and other sandstone-type uranium deposits may be the presence and concentration of dissolved free oxygen in the ore-forming. solutions. Although dissolved oxygen is a necessary prerequisite for the formation of roll-type deposits, it is proposed that a lack of dissolved oxygen is a prerequisite for the Uravan deposits. Solutions that formed both types of deposits probably had a supergene origin and originated as meteoric water in approximate equilibrium with atmospheric oxygen. Roll-type deposits were formed where the Eh dropped abruptly following consumption of the oxygen by iron sulfide minerals and creation of kinetically active sulfur species that could reduce uranium. The solutions that formed the Uravan deposits, on the other hand, probably first equilibrated with sulfide-free ferrous-ferric detrital minerals and fossil organic matter in the host rock. That is, the uraniferous solutions lost their oxygen without lowering their Eh enough to precipitate uranium. Without oxygen, they then. became incapable of oxidizing iron sulfide minerals. Subsequent localization and formation of ore bodies from these oxygen-depleted solutions, therefore, was not necessarily dependent on large reducing capacities.

Uranium deposits at Shinarump Mesa and some adjacent areas in the Temple Mountain district, Emery County, Utah

USGS Publications Warehouse

Wyant, Donald G.

1953-01-01

Deposits of uraniferous hydrocarbons are associated with carnotite in the Shinarump conglomerate of Triassic age at Shinarump Mesa and adjacent areas of the Temple Mountain district in the San Rafael Swell of Emery County, Utah. The irregular ore bodies of carnotite-bearing sandstone are genetically related to lenticular uraniferous ore bodies containing disseminated asphaltitic and humic hydrocarbon in permeable sandstones and were localized indirectly by sedimentary controls. Nearly non-uraniferous bitumen commonly permeates the sandstones in the Shinarump conglomerate and the underlying Moekopi formation in the area. The ore deposits at Temple Mountain have been altered locally by hydrothermal solutions, and in other deposits throughout the area carnotite has been transported by ground and surface water. Uraniferous asphaltite is thought to be the non-volatile residue of an original weakly uraniferous crude oil that migrated into the San Rafael anticline; the ore metals concentrated in the asphaltite as the oil was devolatilized and polymerized. Carnotite is thought to have formed from the asphaltite by ground water leaching. It is concluded that additional study of the genesis of the asphaltitic uranium ores in the San Rafael Swell, of the processes by which the hydrocarbons interact and are modified (such as heat, polymerization, and hydrogenation under the influence of alpha-ray bombardment), of petroleum source beds, and of volcanic intrusive rocks of Tertiary age are of fundamental importance in the continuing study of the uranium deposits on the Colorado Plateau.

Geological and geochemical aspects of uranium deposits: a selected, annotated bibliography. Vol. 2, Rev. 1. [490 references

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, J.M.; Brock, M.L.; Garland, P.A.

1979-07-01

This bibliography, a compilation of 490 references, is the second in a series compiled from the National Uranium Resource Evaluation (NURE) Bibliographic Data Base. This data base is one of six data bases created by the Ecological Sciences Information Center, Oak Ridge National Laboratory, for the Grand Junction Office of the Department of Energy. Major emphasis for this volume has been placed on uranium geology, encompassing deposition, genesis of ore deposits, and ore controls; and prospecting techniques, including geochemistry and aerial reconnaissance. The following indexes are provided to aid the user in locating references of interest: author, geographic location, quadranglemore » name, geoformational feature, taxonomic name, and keyword.« less

Distribution of uranium in the Bisbee district, Cochise County, Arizona

USGS Publications Warehouse

Wallace, Stewart R.

1956-01-01

The Bisbee district has been an important source of copper for many years, and substantial amounts of lead and zinc ore and minor amounts of manganese ore have been mined during certain periods. The copper deposits occur both as low-grade disseminated ore in the Sacramento Hill stock and as massive sulfide (and secondary oxide and carbonate) replacement bodies in Paleozoic limestones that are intruded by the stock and related igneous bodies. The lead-zinc production has come almost entirely from limestone replacement bodies. The disseminated ore exhibits no anomalous radioactivity, and samples from the Lavender pit contain from 0.002 to less than 0.001 percent equivalent uranium. The limestone replacement ores are distinctly radioactive and stoping areas can be readily distinguished from from unmineralized ground on the basis of radioactivity alone. The equivalent uranium content of the copper replacement ores ranges from 0.002 to 0.014 percent and averages about 0.005 percent; the lead-zinc replacement ores average more than 0.007 percent equivalent uranium. Most of the uranium in the copper ores of the district is retained in the smelter slag of a residual concentrate; the slag contains about 0.009 percent equivalent uranium. Uranium carried off each day by acid mine drainage is roughly equal to 1 percent of that being added to the slag dump. Although the total amount of uranium in the district is large, no minable concentrations of ore-grade material are known; samples of relatively high-grade material represent only small fractions of tons at any one locality.

Applied technology for mine waste water decontamination in the uranium ores extraction from Romania

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bejenaru, C.; Filip, G.; Vacariu, V.T.

1996-12-31

The exploitation of uranium ores in Romania is carried out in underground mines. In all exploited uranium deposits, mine waste waters results and will still result after the closure of uranium ore extraction activity. The mine waters are radioactively contaminated with uranium and its decay products being a hazard both for underground waters as for the environment. This paper present the results of research work carried out by authors for uranium elimination from waste waters as the problems involved during the exploitation process of the existent equipment as its maintenance in good experimental conditions. The main waste water characteristics aremore » discussed: solids as suspension, uranium, radium, mineral salts, pH, etc. The moist suitable way to eliminate uranium from mine waste waters is the ion exchange process based on ion exchangers in fluidized bed. A flowsheet is given with main advantages resulted.« less

The roles of organic matter in the formation of uranium deposits in sedimentary rocks

USGS Publications Warehouse

Spirakis, C.S.

1996-01-01

Because reduced uranium species have a much smaller solubility than oxidized uranium species and because of the strong association of organic matter (a powerful reductant) with many uranium ores, reduction has long been considered to be the precipitation mechanism for many types of uranium deposits. Organic matter may also be involved in the alterations in and around tabular uranium deposits, including dolomite precipitation, formation of silicified layers, iron-titanium oxide destruction, dissolution of quartz grains, and precipitation of clay minerals. The diagenetic processes that produced these alterations also consumed organic matter. Consequently, those tabular deposits that underwent the more advanced stages of diagenesis, including methanogenesis and organic acid generation, display the greatest range of alterations and contain the smallest amount of organic matter. Because of certain similarities between tabular uranium deposits and Precambrian unconformity-related deposits, some of the same processes might have been involved in the genesis of Precambrian unconformity-related deposits. Hydrologic studies place important constraints on genetic models of various types of uranium deposits. In roll-front deposits, oxidized waters carried uranium to reductants (organic matter and pyrite derived from sulfate reduction by organic matter). After these reductants were oxidized at any point in the host sandstone, uranium minerals were reoxidized and transported further down the flow path to react with additional reductants. In this manner, the uranium ore migrated through the sandstone at a rate slower than the mineralizing ground water. In the case of tabular uranium deposits, the recharge of surface water into the ground water during flooding of lakes carried soluble humic material to the water table or to an interface where humate precipitated in tabular layers. These humate layers then established the chemical conditions for mineralization and related alterations. In the case of Precambrian unconformity-related deposits, free thermal convection in the thick sandstones overlying the basement rocks carried uranium to concentrations of organic matter in the basement rocks.

Geology of the Ralston Buttes district, Jefferson County, Colorado: a preliminary report

USGS Publications Warehouse

Sheridan, Douglas M.; Maxwell, Charles H.; Albee, Arden L.; Van Horn, Richard

1956-01-01

The Ralston Buttes district in Jefferson County is one of the most significant new uranium districts located east of the Continental Divide in Colorado. The district is east of the Colorado Front Range mineral belt, along the east front of the range. From November 1953 through October 1956, about 10,000 tons of uranium ore, much of which was high-grade pitchblende-bearing vein material, was shipped from the district. The ore occurs in deposits that range in size from bodies containing less than 50 tons to ore shoots containing over 1,000 tons. The only other mining activity in the area has been a sporadic production of beryl, feldspar, and scrap mica from Precambrian pegmatites, and quarrying of dimension stone, limestone, and clay from sedimentary rocks. Most of the Ralston Buttes district consists of complexly folded Precambrian metamorphic and igneous rocks - gneiss, schist, quartzite, amphibolite, and granodiorite. Paleozoic and Mesozoic sedimentary rocks crop out in the northeastern part of the district. These rocks are cut by northwesterly-trending fault systems of Laramide age and by small bodies of intrusive rocks that are Tertiary in age. The typical uranium deposits in the district are hydrothermal veins occupying openings in Laramide fault breccias or related fractures that cut the Precambrian rocks. Pitchblende and lesser amounts of secondary uranium minerals are associated with sparse base-mental sulfides in a gangue of carbonate minerals, potash feldspar, and, more rarely, quartz. Less common types of deposits consist of pitchblende and secondary uranium minerals that occupy fractures cutting pegmatites and quartz veins. The uranium deposits are concentrated in two areas, the Ralston Creek area and the Golden Gate Canyon area. The deposits in the Ralston Creek area are located along the Rogers fault system, and the deposits in the Golden Gate Canyon area are along the Hurricane Hill fault system. Two geologic factors were important to the localization of the uranium deposits: (1) favorable structural environment and (2) favorable host rocks. The deposits in each of the two major areas are located where a northwesterly-trending Laramide fault system splits into a complex network of faults. Also, most of the deposits appear to be localized where the faults cut Precambrian rocks rich in hornblende, biotite, or garnet and biotite. The ore controls recognized in this relatively new uranium district may have wider application in areas of similar geology elsewhere in the Front Range.

Preliminary Report on the White Canyon Area, San Juan County, Utah

USGS Publications Warehouse

Benson, William Edward Barnes; Trites, A.F.; Beroni, E.P.; Feeger, J.A.

1952-01-01

The White Canyon area in San Juan County, Utah, contains known deposits of copper-uranium ore and is currently being mapped and studied by the Geological Survey. To date, approximately 75 square miles, or about 20 percent of the area, has been mapped on a scale 1 inch=1 mile. The White Canyon area is underlain by more than 2,000 feet of sedimentary rocks, Carboniferous to Jurassic(?) in age. The area is on the flank of the Elk Ridge anticline, and the strata have a regional dip of 1 deg to 2 deg SW. The Shinarump conglomerate of Late Triassic age is the principal ore-bearing formation. The Shinarump consists of lenticular beds of sandstone, conglomeratic sandstone, clay, and siltstone, and ranges in thickness from a feather edge to as much as 75 feet. Locally the sandstones contain silicified and carbonized wood and fragments of charcoal. These vegetal remains are especially common in channel-fill deposits. Jointing is prominent in the western part of the area, and apparently affects all formations. Adjacent to the joints some of the redbeds in the sequence are bleached. Deposits of copper-uranium minerals have been found in the Moenkopi, Shinarump, and Chinle formations, but the only production of ore has been from the Shinarump conglomerate. The largest concentration of these minerals is in the lower third of the Shinarump, and the deposits seem to be controlled in part by ancient channel fills and in part by fractures. Locally precipitation of the copper and uranium minerals apparently has been aided by charcoal and clays. Visible uranium minerals include both hard and soft pitchblende and secondary hydrosulfates, phosphates, and silicates. In addition, unidentified uranium compounds are present in carbonized wood and charcoal, and in veinlets of hydrocarbons. Base-metal sulfides have been identified in all prospects that extend beyond the oxidized zone. Secondary copper minerals in the oxidized zone include the hydrous sulfates and carbonates, and possibly chrysocolla. The principal gangue minerals are quartz, clay minerals, chlorite, oxides of iron and manganese, alunite, calcite, gypsum, pyrite, allophane, gibbsite, opal, and chalcedony. The origin of the copper-uranium ores has not been determined, but the association of many deposits with fractures, the mineralogic assemblage, and a lead-uranium age determination of 50 to 60 million years for the pitchblende in the Happy Jack mine favor the hypothesis that the ores are of hydrothermal origin and were deposited in early Tertiary time. Criteria believed to be the most useful in prospecting for new deposits are (1) visible uranium minerals; (2) visible copper minerals; (3) alunite; (4) hydrocarbons; and (5) bleaching of the underlying Moenkopi formation.

Exploration for uranium-vanadium deposits by the U.S. Geological Survey in the Club Mesa area, Uravan district, Montrose County, Colorado

USGS Publications Warehouse

Boardman, R.L.; Litsey, L.R.; Bowers, H.E.

1958-01-01

Club Mesa is one of the most productive areas for uranium-vanadium ore in southwestern Colorago. The average grade of this ore has ranged from about 0.25 to 1.50 percent U3O8 and 1.5 to 5.0 percent V2O5.

U redox fronts and kaolinisation in basement-hosted unconformity-related U ores of the Athabasca Basin (Canada): late U remobilisation by meteoric fluids

NASA Astrophysics Data System (ADS)

Mercadier, Julien; Cuney, Michel; Cathelineau, Michel; Lacorde, Mathieu

2011-02-01

Proterozoic basement-hosted unconformity-related uranium deposits of the Athabasca Basin (Saskatchewan, Canada) were affected by significant uranium redistribution along oxidation-reduction redox fronts related to cold and late meteoric fluid infiltration. These redox fronts exhibit the same mineralogical and geochemical features as the well-studied uranium roll-front deposits in siliclastic rocks. The primary hydrothermal uranium mineralisation (1.6-1.3 Ga) of basement-hosted deposits is strongly reworked to new disseminated ores comprising three distinctly coloured zones: a white-green zone corresponding to the previous clay-rich alteration halo contemporaneous with hydrothermal ores, a uranium front corresponding to the uranium deposition zone of the redox front (brownish zone, rich in goethite) and a hematite-rich red zone marking the front progression. The three zones directly reflect the mineralogical zonation related to uranium oxides (pitchblende), sulphides, iron minerals (hematite and goethite) and alumino-phosphate-sulphate (APS) minerals. The zoning can be explained by processes of dissolution-precipitation along a redox interface and was produced by the infiltration of cold (<50°C) meteoric fluids to the hydrothermally altered areas. U, Fe, Ca, Pb, S, REE, V, Y, W, Mo and Se were the main mobile elements in this process, and their distribution within the three zones was, for most of them, directly dependent on their redox potential. The elements concentrated in the redox fronts were sourced by the alteration of previously crystallised hydrothermal minerals, such as uranium oxides and light rare earth element (LREE)-rich APS. The uranium oxides from the redox front are characterised by LREE-enriched patterns, which differ from those of unconformity-related ores and clearly demonstrate their distinct conditions of formation. Uranium redox front formation is thought to be linked to fluid circulation episodes initiated during the 400-300 Ma period during uplift and erosion of the Athabasca Basin when it was near the Equator and to have been still active during the last million years. A major kaolinisation event was caused by changes in the fluid circulation regime, reworking the primary uranium redox fronts and causing the redistribution of elements originally concentrated in the uranium-enriched meteoric-related redox fronts.

Application of neodymium isotope ratio measurements for the origin assessment of uranium ore concentrates.

PubMed

Krajkó, Judit; Varga, Zsolt; Yalcintas, Ezgi; Wallenius, Maria; Mayer, Klaus

2014-11-01

A novel procedure has been developed for the measurement of (143)Nd/(144)Nd isotope ratio in various uranium-bearing materials, such as uranium ores and ore concentrates (UOC) in order to evaluate the usefulness and applicability of variations of (143)Nd/(144)Nd isotope ratio for provenance assessment in nuclear forensics. Neodymium was separated and pre-concentrated by extraction chromatography and then the isotope ratios were measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method was validated by the measurement of standard reference materials (La Jolla, JB-2 and BCR-2) and the applicability of the procedure was demonstrated by the analysis of uranium samples of world-wide origin. The investigated samples show distinct (143)Nd/(144)Nd ratio depending on the ore type, deposit age and Sm/Nd ratio. Together with other characteristics of the material in question, the Nd isotope ratio is a promising signature for nuclear forensics and suggests being indicative of the source material, the uranium ore. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Economic Geology (Metals)

ERIC Educational Resources Information Center

Gair, Jacob E.

1972-01-01

Reviews metalliferous ore-deposit research reported in 1971. Research was dominated by isotopic studies, and worldwide metals exploration was marked by announcements of important new discoveries of base metals, iron ore, nickel, titanium, and uranium. (Author/PR)

Geology of the Shinarump No. 1 uranium mine, Seven Mile Canyon area, Grand County, Utah

USGS Publications Warehouse

Finch, Warren Irvin

1953-01-01

The Shinarump No. 1 uranium mine is located about 12 miles northwest of Moab, Utah, in the Seven Mile Canyon area, Grand County, Utah. A study was made of the geology of the Shinarump No. 1 mine in order to determine the habits, ore controls, and possible origin of the deposit. Rocks of Permain, Triassic, and Jurassic age crop out in the area mapped. Uranium deposits are found in three zones in the lower 25 feet of the Upper Triassic Chinle formation. The Shinarump No. 1 mine, which is in the lowermost zone, is located on the west flank of the Moab anticline near the Moab fault. The Shinarump No. 1 uranium deposit consists of discontinuous lenticular layers of mineralized rock, irregular in outline, that, in general, follow the bedding. Ore minerals, mainly uranite, impregnate the rock. High-grade seams of uranite and chalcocite occur along bedding planes. Formation of unraninite is later than or simultaneous with most sulfides. Chalcocite may be of two ages, with some being later than uraninite. Uraninite and chalcocite are concentrated in the poorer sorted parts of siltstones. Guides to ore in the Seven Mile Canyon area inferred from the study of the Shinarump No. 1 deposit are the presence of bleached siltstone, copper sulfides, and carbonaceous matter. Results of spectrographic analysis indicated that the mineralizing solutions contained important amounts of barium, vanadium, uranium, and copper as well as lesser amounts of strontium, chromium, boron, yttrium, lead, and zinc. The origin of the Shinarump No. 1 deposit is thought to be hydrothermal, dated as later or early.

Early Jurassic mafic dykes from the Aigao uranium ore deposit in South China: Geochronology, petrogenesis and relationship with uranium mineralization

NASA Astrophysics Data System (ADS)

Zhang, Di; Zhao, Kui-Dong; Chen, Wei; Jiang, Shao-Yong

2018-05-01

Mafic dykes are abundant and widely distributed in many granite-hosted uranium ore deposits in South China. However, their geochronology, petrogenesis and relationship with uranium mineralization were poorly constrained. In this study, apatite U-Pb dating, whole-rock major and trace element and Sr-Nd-Pb isotope analysis were conducted for the dolerite dykes from the Aigao uranium ore deposit. Apatite U-Pb isotopic data indicate that the mafic dykes were emplaced at Early Jurassic (189 ± 4 Ma), which provides new evidence for the rarely identified Early Jurassic magmatism in South China. Pyroxene from the dykes is mainly augite, and plagioclase belongs to albite. The dolerite samples have relatively low SiO2 contents (45.33-46.79 wt%), relatively high total alkali contents (K2O + Na2O = 4.11-4.58 wt%) and Al2O3 contents (13.39-13.80 wt%), and medium MgO contents (4.29-5.16 wt%). They are enriched in Nb, Ta, Ti, rare earth elements and depleted in Rb, K, Sr, Th, showing the typical OIB-like geochemical affinity. All the dolerite samples show homogeneous Sr-Nd-Pb isotopic compositions, with (87Sr/86Sr)i varying from 0.706049 to 0.707137, εNd(t) from +4.6 to +5.2, 206Pb/204Pb from 19.032 to 19.126 and 207Pb/204Pb from 15.641 to 15.653. The mafic dykes in the Aigao deposit should be derived from the partial melting of the asthenospheric mantle and formed in a within-plate extensional environment. The emplacement age of the mafic dykes is older than the uranium mineralization age. Therefore, CO2 in ore-forming fluids couldn't originate from the basaltic magma as suggested by previous studies. The dolerite dykes might only provide a favorable reducing environment to promote the precipitation of uraninite from oxidize hydrothermal fluids.

Preliminary investigation of the elemental variation and diagenesis of a tabular uranium deposit, La Sal Mine, San Juan County, Utah

USGS Publications Warehouse

Brooks, Robert A.; Campbell, John A.

1976-01-01

Ore in the La Sal mine, San Juan County, Utah, occurs as a typical tabular-type uranium deposit of the-Colorado Plateau. Uranium-vanadium occurs in the Salt Wash Member of the Jurassic Morrison Formation. Chemical and petrographic analyses were used to determine elemental variation and diagenetic aspects across the orebody. Vanadium is concentrated in the dark clay matrix, which constitutes visible ore. Uranium content is greater above the vanadium zone. Calcium, carbonate carbon, and lead show greater than fifty-fold increase across the ore zone, whereas copper and organic carbon show only a several-fold increase. Large molybdenum concentrations are present in and above the tabular layer, and large selenium concentrations occur below the uranium zone within the richest vanadium zone. Iron is enriched in the vanadium horizon. Chromium is depleted from above the ore and strongly enriched below. Elements that vary directly with the vanadium content include magnesium, iron, selenium, zirconium, strontium, titanium, lead, boron, yttrium, and scandium. The diagenetic sequence is as follows: (1) formation of secondary quartz overgrowths as cement; (2) infilling and lining of remaining pores with amber opaline material; (3) formation of vanadium-rich clay matrix, which has replaced overgrowths as well as quartz grains; (4) replacement of overgrowths and detrital grains by calcite; (5) infilling of pores with barite and the introduction of pyrite and marcasite.

[The characteristics of type I, III collagen and LN in pulmonary fibrosis induced by uranium ore dust in rats].

PubMed

Hu, Ying-chun; Luo, Zhen-hua; Yuan, Xing-jiang; Yang, Li-ping; Wang, Shou-feng; Li, Guang-yue; He, Xing-peng

2011-02-01

To explore the characteristics of LN and type I, III collagen in pulmonary fibrosis induced by uranium ore dust in rats. 60 adult Wistar rats were divided randomly into two groups, control group (30 rats) and uranium ore dust group (30 rats). Non-exposed intratracheal instillation method was used. Uranium ore dust group was exposed 20 mg/ml uranium ore dust suspension 1ml per rat, meanwhile control group was exposed normal saline 1ml per rat. Post-exposed the 7, 14, 21, 30 and 60 d, 6 rats in each group were killed randomly, lung tissue were collected. The pathological changes in lung tissue were observed by microscope using HE staining, the collagen I and III in lungs were observed by polarizing microscope using Biebrich scarlet staining. The expression of LN protein in lung tissue was observed by immunohistochemistry-SP. During lung fibrosis, a large amount of the proliferated I and III collagen in lungs were observed. Post-exposure to uranium ore dust, the characteristics in proliferated collagen in lungs were type I collagen deposited in lung interstitium mainly in the early stage. The area percentage of collagen I and III was increased significantly at 7, 14, 21, 30 and 60d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01). The over expression of LN in the lung tissue were observed. The expression of LN was distributed in the lung tissue as thickening of the linear or cluster. The integral optical density of LN was increased significantly at 21, 30 and 60 d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01). After exposure to uranium ore dust, the characteristics in proliferated collagen in lungs are the type of I collagen deposited in lung interstitium mainly in the early stage, while the type of III collagen increase significantly at the later period. The overexpression of LN exists in the process of pulmonary fibrosis. It suggests that LN has a role effect in the process of pulmonary fibrosis.

Potential Aquifer Vulnerability in Regions Down-Gradient from Uranium In Situ Recovery (ISR) Sites

EPA Science Inventory

Sandstone-hosted roll-front uranium ore deposits originate when U(VI) dissolved in groundwater is reduced and precipitated as insoluble U(IV) minerals. Groundwater redox geochemistry, aqueous complexation, and solute migration are instrumental in leaching uranium from source rock...

The Main Factors of Uranium Accumulation in the Ishim Plain Saline Lakes (Western Siberia)

NASA Astrophysics Data System (ADS)

Vladimirov, A. G.; Krivonogov, S. K.; Karpov, A. V.; Nikolaeva, I. V.; Razvorotneva, L. I.; Kolpakova, M. N.; Moroz, E. N.

2018-04-01

Hydrochemical analysis of the high-salinity lakes in the Ishim Plain (>250-300 g/L) located at the border with the Northern Kazakhstan uranium ore province is performed. The studies have shown that the main factor of concentration and redistribution of uranium in the lake basins of the Ishim Plain are the processes of intense salt deflation causing sanding of lakes and uranium depletion in the near-surface layer of the bottom deposits. The correlation between the hydroxide forms of uranium binding in the bottom lacustrine deposits of the Ishim Plain and the coffinite composition of the Semizbai deposit makes it possible to consider this province to be promising for the discovery of hydromineral uranium deposits.

Comparison of the mineralogy of the Boss-Bixby, Missouri copper-iron deposit, and the Olympic Dam copper-uranium-gold deposit, South Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandom, R.T.; Hagni, R.D.; Allen, C.R.

1985-01-01

An ore microscopic examination of 80 polished sections prepared from selected drill core specimens from the Boss-Bixby, Missouri copper-iron deposit has shown that its mineral assemblage is similar to that of the Olympic Dam (Roxby Downs) copper-uranium-gold deposit in South Australia. A comparison with the mineralogy reported for Olympic Dam shows that both deposits contain: 1) the principal minerals, magnetite, hematite, chalcopyrite, and bornite, 2) the cobalt-bearing phases, carrollite and cobaltian pyrite, 3) the titanium oxides, rutile and anatase, 4) smaller amounts of martite, covellite, and electrum, 5) fluorite and carbonates, and 6) some alteration minerals. The deposits also aremore » similar with regard to the sequence of mineral deposition: 1) early oxides, 2) then sulfide minerals, and 3) a final oxide generation. The deposits, however, are dissimilar with regard to their host rock lithologies and structural settings. The Boss-Bixby ores occupy breccia zones within a hydrothermally altered basic intrusive and intruded silicic volcanics, whereas the Olympic Dam ores are contained in sedimentary breccias in a graben or trough. Also, some minerals have been found thus far to occur at only one of the deposits. The similarity of mineralogy in these deposits suggests that they were formed from ore fluids that had some similarities in character and that the St. Francois terrane of Missouri is an important region for further exploration for deposits with this mineral assemblage.« less

Preliminary report on the White Canyon area, San Juan county, Utah

USGS Publications Warehouse

Benson, William E.; Trites, Albert F.; Beroni, Ernest P.; Feeger, John A.

1952-01-01

The White Canyon area, in the central part of San Juan County, Utah, consists of approximately two 15-minute quadrangles. Approximately 75 square miles have been mapped by the Geological Survey on a scale of 1 inch equals 1 mile, using a combined aerial photography-plane table method. Structure contours were drawn on top of the Organ Rock member of the Cutler formation. Parts of the Gonway and North Point claims, 1/4 mile east of the Happy Jack mine, were mapped in detail. The principal objectives of the investigations were: (1) to establish ore guides; (2) to select areas favorable for exploration; and (3) to map the general geology and to determine the regional relationships of the uranium deposits. The White Canyon area is comprised of sedimentary rocks of Carboniferous to Jurassic age, more than 2,000 feet thick, having a regional dip of 1° to 2° SW. The nearest igneous rocks are in the Henry Mountains about 7 miles west of the northern part of the area; The Shinarump conglomerate of the late Triassic age, the principal ore horizon in the White Canyon area, consists of lenticular beds of sandstone, conglomeratic sandstone, conglomerate, clay, and siltstone. The Shinarump conglomerate, absent in places, is as much as 75 feet thick. The sandstones locally contain molds of logs and fragments of altered volcanic ash. Some of the logs have been replaced by copper and uranium minerals and iron oxides. The clay and siltstone underlie and are interbedded with the sandstone, and are most common in channels that cut into the underlying Moenkopi formation. The Shinarump conglomerate contains reworked Moenkopi siltstone fragments, clay balls, carbonized wood, and pebbles of quarts, quartzite, and chert. Jointing is prominent in the Western part of the mapped area. The three most prominent joint trends are due east, N. 65°-75° W., and N. 65°-75° E. All joints have vertical dips. The red beds are bleached along some joints, especially those that trend N. 65°-75° W. All uranium ore produced has been from the lower part of the Shinarump conglomerate, where it commonly occurs with copper as disseminations and fracture coatings in sandstone. Uranium and copper minerals also occur in low-grade disseminated deposits in the lower Chinle and in the Moenkopi formation and in veins cutting these formations. Although some uranium deposits occur in Chinarump channels and scours, copper and uranium minerals along fractures suggest that channel control may be secondary. Logs and clay balls apparently have exerted some chemical influences for deposition. The uranium occurs as the oxide in some deposits, and as secondary hydrous sulfates, phosphates, oxides, and silicates in these and several other deposits. Charcoal, iron and manganese oxides, and veinlets of hydrocarbon are abnormally radioactive in most of the deposits. Base-metal sulfides are commonly found inside the oxidized zone. Secondary copper minerals include the hydrous sulfates and carbonate. Gangue minerals include quarts, clay minerals, and manganese oxides, dickite (?), calcite, gypsum, pyrite, and chalcedony (?). Principal wall-rock alteration appears to have been silicification, clay alteration, and bleaching. Most of the shipped ore has contained more than 0.3 percent uranium. The ore also contains copper, commonly in grades lower than 1.0 percent. Criteria believed to be most useful for prospecting for concealed uranium deposits are (1) visible uranium minerals; (2) sulfide minerals; (3) secondary copper minerals; (4) dickite (?); (5) hydrocarbons; and (6) bleaching and alteration of the Moenkopi formation.

Some concepts of favorability for world-class-type uranium deposits in the northeastern United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adler, H.H.

1981-03-01

An account is given of concepts of favorability of geologic environments in the eastern United States for uranium deposits of several major types existing elsewhere in the world. The purpose is to convey some initial ideas about the interrelationships of the geology of the eastern United States and the geologic settings of certain of these world-class deposits. The study and report include consideration of uranium deposits other than those generally manifesting the geologic, geochemical and genetic characteristics associated with the conventional sandstone-type ores of the western United States.

Occurrence of Uranium Ores in the Schist Formation of the Pre-Ordovician Portugal; OCCURENCE DE MINERAIS D'URANIUM DANS LES FORMATIONS DE SCHISTES ANTE-ORDOVICIENS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lobato, C.P.; Ferrao, C.N.

1959-10-31

The occurrence of uranium ores in concentrations of economical interest in the pre-ordovician schists was noted by the first time, in the region of Pinhel, in November 1958. The occurrence is situated in a zone of graphitic brown-greyish schists which are enclosed in a formation of gneiss with tourmaline near the contact of the latter with the hercinian granite, which constitutes the Beiras' Massif. The uraniferous mineralization is constituted by autunite down to the depth which has been reached by the explorntion work. The radiometric study and the sampling taken nt the depth of about ten meters suggest the continuitymore » of the structure and the persistence of the mineralization associated with it. The structural type and the distribution of the mineralization in the joints and the brecciated zone of the schists suggest that the deposition of uranium ore is not syngenetic, but, rather, that it is attribated to the circulation of mineralized solutions through the breakage produced along the hypothermal veilns, in a posterior reopening connected to the last movements of the alpidic orogenesis. The content obtained in the sampling reveals the existence of an enlarged ore deposit following the directions of the schistosity, wfth an extension of 140 meters and with the medium content of 0.27% U/sub 3/O/ sub 8/. (auth)« less

Comparison of abundances of chemical elements in mineralized and unmineralized sandstone of the Brushy Basin Member of the Morrison Formation, Smith Lake District, Grants uranium region, New Mexico

USGS Publications Warehouse

Pierson, C.T.; Spirakis, C.S.; Robertson, J.F.

1983-01-01

Statistical treatment of analytical data from the Mariano Lake and Ruby uranium deposits in the Smith Lake district, New Mexico, indicates that organic carbon, arsenic, barium, calcium, cobalt, copper, gallium, iron, lead, manganese, molybdenum, nickel, selenium, strontium, sulfur, vanadium, yttrium, and zirconium are concentrated along with uranium in primary ore. Comparison of the Smith Lake data with information from other primary deposits in the Grants uranium region and elsewhere in the Morrison Formation of the Colorado Plateau suggests that these elements, with the possible exceptions of zirconium and gallium and with the probable addition of aluminum and magnesium, are typically associated with primary, tabular uranium deposits. Chemical differences between the Ruby and Mariano Lake deposits are consistent with the interpretation that the Ruby deposit has been more affected by post-mineralization oxidizing solutions than has the Mariano Lake deposit.

Materials. Section 1 of Symposium on the peaceful uses of atomic energy in Australia, 1958, held in Sydney, in June 1958

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The environments of the known uranium occurences in South Australia arc described, and the relation of uranium mineralization with sodic granitic rocks is emphasized. The problems in designing equipment for radiometric prospecting are reviewed. The fabrication and properties of BeO, UO/sub 2/, ThO/sub 2/, and mixed oxides are discussed. The use of pulsing in a uranium extraction pilot plant ion exchange column is described. The wetting of metals by liquid metals is reviewed with emphasis on liquid sodium. The geological nature, extent, and future prospects of minerals with atomic energy applications, occurring in New South Wales are outlined. The developmentmore » of a process for uranium recovery from Mary Kathleen ores is described. Techniques and processes involved in locating, mining, and concentrating davidite-type ores at Radium Hill, South Australia are described. The uranium deposits of the Northern Territory, Australia, are classified and described. The flotation behavior of the simple oxide minerals, uraninite and the colloform variety is discussed. The Port Pirie Treatment Plant for uranium recovery from refractory Radium Hill concentrates is described. The plant utilizes the sulfuric acid-ion exchange process. The uranium deposits of Queensland are described. the details of the production of uranium ore concentrates at Rum jungle near Darwin, Australia, are given. A brief account of the use of neutron diffraction analysis in crystallography is given, and the neutron spectrometers installed on the High Flux Australian Research Reactor are described. (T.R.H.)« less

Investigation of mine and industry dumps in the FRG in relation to a possible release of natural radioactive elements.

PubMed

Schmitz, J

1985-10-01

More than 350 dumps of mines and industries in two federal states of the FRG were recorded, measured radiometrically, evaluated, and some of them sampled. Most of the mine dumps belonged to old and smaller residues from lead/zinc and iron ore mining, while the largest depositions contain tailings of modern ore beneficiation or flyash disposal. All mine dumps from uranium exploration in Baden-Württemberg and Bavaria were investigated. The highest doses, up to 100 mSv/a, were found on the piles of the uranium exploration. These depositions, which are supervised and licensed, are followed, in terms of surface dose, by the old uncontrolled mine dumps of silver/cobalt mining with doses up to 20 mSv/a. The numerous porphyry and granite quarries show doses between 1 and 2 mSv/a, as do flyash and slag dumps. The lowest doses were found on the dumps of the hydrothermal Pb/Zn and iron ore deposits, while the slag piles of iron ore processing showed higher thorium values. Assays for Ra-226 and Pb-210 of the materials deposited confirmed the radiometric results. Analyses of seepage waters and gallery waters showed only very few values exceeding the derived drinking water concentrations.

Iron disulfide minerals and the genesis of roll-type uranium deposits.

USGS Publications Warehouse

Reynolds, R.L.; Goldhaber, M.B.

1983-01-01

Studies of the distribution of and textural relationships among pyrite and marcasite in host rocks for a number of roll-type sedimentary U deposits have enabled identification of several generations of FeS2 minerals. A critical factor influencing mineral formation is the complex relationship of pH and the S species that are precursors of FeS2 minerals. The presence or absence of intrinsic organic matter for bacterial sulphate reduction also plays a key role. In deposits lacking such organic matter, the pre-ore is often euhedral pyrite and the ore-stage is marcasite. In contrast, in deposits containing organic matter the pre-ore is pyrite occurring as framboids or as replacements of plant material, and the ore-stage is also pyrite. These contrasting FeS2 assemblages and their respective modes of origin are consistent with previously proposed biogenic and nonbiogenic theories of the genesis of roll-type U deposits. -J.E.S.

The uranium-bearing nickel-cobalt-native silver deposits in the Black Hawk district, Grant County, New Mexico

USGS Publications Warehouse

Gillerman, Elliot; Whitebread, Donald H.

1953-01-01

The Black Hawk (Bullard Peak) district, Grant County, N. Mex., is 21 miles by road west of Silver City. From 1881 to 1893 more than $1,000,000.00 of high-grade silver ore is reported to have been shipped from the district. Since 1893 there has been no mining in the district except during a short period in 1917 when the Black Hawk mine was rehabilitated. Pre-Cambrian quartz diorite gneiss, which contains inclusions of quartzite, schist, monzonite, and quartz monzonite, is the most widespread rock in the district. The quartz diorite gneiss is intruded by many pre-Cambrian and younger rocks, including diorite granite, diabase, monzonite porphyry and andesite and is overlain by the Upper Cretaceous Beartooth quartzite. The monzonite porphyry, probably of late Cretaceous or early Tertiary age, forms a small stock along the northwestern edge of the district and numerous dikes and irregular masses throughout the district. The ore deposits are in fissure veins that contain silver, cobalt, and uranium. The ore minerals, which include native silver, niccolite, millerite, skutterudite, nickel skutterudite, bismuthinite, pitchblende, and sphalerite, are in a carbonate gangue in narrow, persistent veins, most of which trend northeasterly. Pitchblende has been identified in the Black Hawk and the Alhabra deposits and unidentified radioactive minerals were found at five other localities. The deposits that contain the radioactive minerals constitude a belt 600 to 1,500 feet wide that trends about N. 45° E., and is approximately parallel to the southeastern boundary of the monzonite porphyry stock. All the major ore deposits are in the quartz diorite gneiss in close proximity to the monzonite porphyry. The ore deposits are similar to the deposits at Great Bear Lake, Canada, and Joachimstahl, Czechoslovakia.

An investigation into heterogeneity in a single vein-type uranium ore deposit: Implications for nuclear forensics.

PubMed

Keatley, A C; Scott, T B; Davis, S; Jones, C P; Turner, P

2015-12-01

Minor element composition and rare earth element (REE) concentrations in nuclear materials are important as they are used within the field of nuclear forensics as an indicator of sample origin. However recent studies into uranium ores and uranium ore concentrates (UOCs) have shown significant elemental and isotopic heterogeneity from a single mine site such that some sites have shown higher variation within the mine site than that seen between multiple sites. The elemental composition of both uranium and gangue minerals within ore samples taken along a single mineral vein in South West England have been measured and reported here. The analysis of the samples was undertaken to determine the extent of the localised variation in key elements. Energy Dispersive X-ray spectroscopy (EDS) was used to analyse the gangue mineralogy and measure major element composition. Minor element composition and rare earth element (REE) concentrations were measured by Electron Probe Microanalysis (EPMA). The results confirm that a number of key elements, REE concentrations and patterns used for origin location do show significant variation within mine. Furthermore significant variation is also visible on a meter scale. In addition three separate uranium phases were identified within the vein which indicates multiple uranium mineralisation events. In light of these localised elemental variations it is recommended that representative sampling for an area is undertaken prior to establishing the REE pattern that may be used to identify the originating mine for an unknown ore sample and prior to investigating impact of ore processing on any arising REE patterns. Copyright © 2015 Elsevier Ltd. All rights reserved.

Uranium resources in the Silver Reef (Harrisburg) district, Washington County, Utah

USGS Publications Warehouse

Stugard, Frederick

1951-01-01

The Silver Reef district is near Leeds, about 16 miles north of St. George, Utah. The major structural feature of the district is the Virgin anticline, a fold extending southwestward toward St. George. The anticline has been breached by erosion, and sandstone hogbacks or 'reefs' are carved from the Shinarump conglomerate mud sandstone members of the Chinle formation, both of Triassic age. Thirteen occurrences of uranium-vanadium minerals, all within the Tecumseh sandstone, which is the upper part of the Silver Reef sandstone member of the Chinle formation, have been examined over an area about 1.75 miles wide and 3 miles long. Two shipments of uranium-vanadium ore have been produced from the Chloride Chief and Silver Point claims. Samples from the deposits contain as much as 0.94 percent U3O8. The ore contains several times as much vanadium oxide as uranium, some copper, and traces of silver. It occurs in thinly bedded cross-bedded shales and sandstones within the fluviatile Tecumseh sandstone member of the Chinle formation. The ore beds are lenticular and are localized 2 near the base, center, and top of this sandstone member. The uranium-vanadium ore contains several yellow and green minerals not yet identified; the occurrences are similar to, but not associated with, the cerargyrite ore that made the district famous from 1879 to 1909.

Uranium deposits at the Jomac mine, White Canyon area, San Juan County, Utah

USGS Publications Warehouse

Trites, A.F.; Hadd, G.A.

1955-01-01

azurite, and chalcanthite occur locally with the uranium minerals. Principal ore guides at the Jomac mine are channels, and scours at the bottom of these channels coal-bearing sandstone or conglomerate at the base of the Shinarump conglomerate, coal, and jarosite.

Origin of the Okrouhlá Radouň episyenite-hosted uranium deposit, Bohemian Massif, Czech Republic: fluid inclusion and stable isotope constraints

NASA Astrophysics Data System (ADS)

Dolníček, Zdeněk; René, Miloš; Hermannová, Sylvie; Prochaska, Walter

2014-04-01

The Okrouhlá Radouň shear zone hosted uranium deposit is developed along the contact of Variscan granites and high-grade metasedimentary rocks of the Moldanubian Zone of the Bohemian Massif. The pre-ore pervasive alteration of wall rocks is characterized by chloritization of mafic minerals, followed by albitization of feldspars and dissolution of quartz giving rise to episyenites. The subsequent fluid circulation led to precipitation of disseminated uraninite and coffinite, and later on, post-ore quartz and carbonate mineralization containing base metal sulfides. The fluid inclusion and stable isotope data suggest low homogenization temperatures (˜50-140 °C during pre-ore albitization and post-ore carbonatization, up to 230 °C during pre-ore chloritization), variable fluid salinities (0-25 wt.% NaCl eq.), low fluid δ18O values (-10 to +2 ‰ V-SMOW), low fluid δ13C values (-9 to -15 ‰ V-PDB), and highly variable ionic composition of the aqueous fluids (especially Na/Ca, Br/Cl, I/Cl, SO4/Cl, NO3/Cl ratios). The available data suggest participation of three fluid endmembers of primarily surficial origin during alteration and mineralization at the deposit: (1) local meteoric water, (2) Na-Ca-Cl basinal brines or shield brines, (3) SO4-NO3-Cl-(H)CO3 playa-like fluids. Pre-ore albitization was caused by circulation of alkaline, oxidized, and Na-rich playa fluids, whereas basinal/shield brines and meteoric water were more important during the post-ore stage of alteration.

Anomalous Lead Isotopic Composition of Galena and Age of Altered Uranium Minerals: a Case study of Chauli Deposits, Chatkal-Qurama District, Uzbekistan

NASA Astrophysics Data System (ADS)

Chernyshev, I. V.; Golubev, V. N.; Chugaev, A. V.

2017-11-01

The enrichment of lead isotopic composition of nonuranium minerals, in the first place galena in 206Pb and 207Pb, as compared to common lead is a remarkable feature of uranium deposits. The study of such lead isotopic composition anomalous in 206Pb and 207Pb in uranium minerals provides an opportunity for not only identification of superimposed processes resulting in transformation of uranium ores during deposit history but also calculation of age of these processes under certain model assumptions. Galena from the Chauli deposit in the Chatkal-Qurama district, Uzbekistan, a typical representative of hydrothermal uranium deposits associated with domains of Phanerozoic continental volcanism, has been examined with the highprecision (±0.02%) MC-ICP-MS method. Twenty microsamples of galena were taken from polished sections. Six of them are galena hosted in carbonate adjacent to pitchblende spherulites or filling thin veinlets (approximately 60 μm) cutting pitchblende. Isotopically anomalous lead with 206Pb/204Pb and 207Pb/204Pb values reaching 20.462 and 15.743, respectively, has been found in these six microsamples in contrast to another fourteen in which the Pb-Pb characteristics are consistent with common lead. On the basis of these data and with account for the 292 ± 2 Ma age for the Chauli deposit, the age of epigenetic transformation of uranium ores of this deposit has been estimated. During this process, radiogenic lead partly lost from pitchblende was captured into galena. The obtained date is 170 Ma. In the Chatkal-Qurama district, these epigenetic processes are apparently caused by the interaction of uranium minerals with activated underground water under tectonic activity and relief transformation, which took place from the post-Permian (i.e., after the Chauli formation) to the Jurassic period.

Organic matter diagenesis as the key to a unifying theory for the genesis of tabular uranium-vanadium deposits in the Morrison Formation, Colorado Plateau

USGS Publications Warehouse

Hansley, P.L.; Spirakis, C.S.

1992-01-01

Interstitial, epigenetic amorphous organic matter is intimately associated with uranium in the Grants uranium region and is considered essential to genetic models for these deposits. In contrast, uranium minerals are intimately associated with authigenic vanadium chlorite and vanadium oxides in amorphous organic matter-poor ores of the Slick Rock and Henry Mountains mining districts and therefore, in some genetic models amorphous organic matter is not considered crucial to the formation of these deposits. Differences in organic matter content can be explained by recognizing that amorphous organic matter-poor deposits have been subjected to more advanced stages of diagenesis than amorphous organic matter-rich deposits. Evidence that amorphous organic matter was involved in the genesis of organic matter-poor, as well as organic matter-rich, deposits is described. -from Authors

The Itataia phosphate-uranium deposit (Ceará, Brazil) new petrographic, geochemistry and isotope studies

NASA Astrophysics Data System (ADS)

Veríssimo, César Ulisses Vieira; Santos, Roberto Ventura; Parente, Clóvis Vaz; Oliveira, Claudinei Gouveia de; Cavalcanti, José Adilson Dias; Nogueira Neto, José de Araújo

2016-10-01

The Itataia phosphate-uranium deposit is located in Santa Quitéria, in central Ceará State, northeastern Brazil. Mineralization has occurred in different stages and involves quartz leaching (episyenitization), brecciation and microcrystalline phase formation of concretionary apatite. The last constitutes the main mineral of Itatiaia uranium ore, namely collophane. Collophanite ore occurs in massive bodies, lenses, breccia zones, veins or episyenite in marble layers, calc-silicate rocks and gneisses of the Itataia Group. There are two accepted theories on the origin of the earliest mineralization phase of Itataia ore: syngenetic (primary) - where the ore is derived from a continental source and then deposited in marine and coastal environments; and epigenetic (secondary) - whereby the fluids are of magmatic, metamorphic and meteoric origin. The characterization of pre- or post-deformational mineralization is controversial, since the features of the ore are interpreted as deformation. This investigation conducted isotopic studies and chemical analyses of minerals in marbles and calc-silicate rocks of the Alcantil and Barrigas Formations (Itataia Group), as well as petrographic and structural studies. Analysis of the thin sections shows at least three phosphate mineral phases associated with uranium mineralizaton: (1) A prismatic fluorapatite phase associated with chess-board albite, arfvedsonite and ferro-eckermannite; (2) a second fluorapatite phase with fibrous radial or colloform habits that replaces calcium carbonate in marble, especially along fractures, with minerals such as quartz, chlorite and zeolite also identified in calc-silicate rocks; and (3) an younger phosphate phase of botryoidal apatite (fluorapatite and hydroxyapatite) related with clay minerals and probably others calcium and aluminum phosphates. Detailed isotopic analysis carried out perpendicularly to the mineralized levels and veins in the marble revealed significant variation in isotopic ratios. Mineralized zones exhibit a decrease in δ13C and δ18O isotope values and a higher 87Sr/86Sr ratio toward the center of the vein. In conjunction with petrographic studies, these changes contesting the hypothesis of a sedimentary origin for uranium and suggest a radiogenic Sr input by alkaline to peralkaline fluids from fertile granites of the end of Brasiliano/Pan-African orogeny, located outside the deposit. The origin of the phosphorous is associated with phosphorite deposits in the same depositional environment of the neoproterozoic supracrustal quartz-pelite-carbonate sediments of the Itataia Group. Considering the studies conducted here and available geological data, three main mineralizing events can be identified in Itataia: (1) an initial high temperature event connected with a sodium metasomatism-related uranium episode, taking place in Borborema Province and its African counterpart; (2) a second lower temperature stage, consisting of a multiphase cataclastic/hydrothermal event limited to fault and paleokarst zones; and (3) a third and final event, developed in frankly oxidizing conditions. The last two involving mixing of hydrothermal and meteoric fluids.

Yellow Canary uranium deposits, Daggett County, Utah

USGS Publications Warehouse

Wilmarth, Verl Richard

1953-01-01

The Yellow Canary uranium deposit is on the west side of Red Creek Canyon in the northern part of the Uinta Mountains, Daggett County, Utah. Two claims have been developed by means of an adit, three opencuts, and several hundred feet of bulldozer trenches. No uranium ore has been produced from this deposit. The deposit is in the pre-Cambrian Red Creek quartzite. This formation is composed of intercalated beds of quartzite, hornblendite, garnet schist, staurolite schist, and quartz-mica schist and is intruded by dioritic dikes. A thick unit of highly fractured white quartzite near the top of the formation contains tyuyamunite as coatings on fracture surfaces. The tyuyamunite is associated with carnotite, volborthite, iron oxides, azurite, malachite, brochantite, and hyalite. The uranium and vanadium minerals are probably alteration products of primary minerals. The uranium content of 15 samples from this property ranged from 0.000 to 0.57 percent.

Exploration for uranium deposits in the Atkinson Mesa area, Montrose County, Colorado

USGS Publications Warehouse

Brew, Daniel Allen

1954-01-01

The U.S. Geological Survey explored the Atkinson Mesa area for uranium- and vanadium-bearing deposits from July 2, 1951, to June 18, 1953, with 397 diamond-drill holes that totaled 261,251 feet. Sedimentary rocks of Mesozoic age are exposed in the Atkinson Mesa area. They are: the Brushy Basin member of the Upper Jurassic Morrison formation, the Lower Cretaceous Burro Canyon formation, and the Upper and Lower Cretaceous Dakota sandstone. All of the large uranium-vanadium deposits discovered by Geological Survey drilling are in a series of sandstone lenses in the upper part of the Salt Wash member of the Jurassic Morrison formation. The deposits are mainly tabular and blanket-like, but some elongate pod-shaped masses, locally called "rolls" may be present. The mineralized material consists of sandstone impregnated with a uranium mineral which is probably coffinite, spme carnotite, and vanadium minerals, thought to be mainly corvusite and montroseite. In addition,, some mudstone and carbonaceous material is similarly impregnated. Near masses of mineralized material the sandstone is light gray or light brown, is generally over 40 feet thick, and usually contains some carbonaceous material and abundant disseminated pyrite or limonite stain. Similarly, the mudstone in contact with the ore-bearing sandstone near bodies of mineralized rock is commonly blue gray, as compared to its dominant red color away from ore deposits. Presence and degree of these features are useful guides in exploring for new deposits.

Mineral and energy resources of the BLM Roswell Resource Area, east-central New Mexico

USGS Publications Warehouse

Bartsch-Winkler, Susan B.

1992-01-01

The sedimentary formations of the Roswell Resource Area have significant mineral and energy resources. Some of the pre-Pennsylvanian sequences in the Northwestern Shelf of the Permian Basin are oil and gas reservoirs, and Pennsylvanian rocks in Tucumcari basin are reservoirs of oil and gas as well as source rocks for oil and gas in Triassic rocks. Pre-Permian rocks also contain minor deposits of uranium and vanadium, limestone, and associated gases. Hydrocarbon reservoirs in Permian rocks include associated gases such as carbon dioxide, helium, and nitrogen. Permian rocks are mineralized adjacent to the Lincoln County porphyry belt, and include deposits of copper, uranium, manganese, iron, polymetallic veins, and Mississippi-valley-type (MVT) lead-zinc. Industrial minerals in Permian rocks include fluorite, barite, potash, halite, polyhalite, gypsum, anhydrite, sulfur, limestone, dolomite, brine deposits (iodine and bromine), aggregate (sand), and dimension stone. Doubly terminated quartz crystals, called "Pecos diamonds" and collected as mineral specimens, occur in Permian rocks along the Pecos River. Mesozoic sedimentary rocks are hosts for copper, uranium, and small quantities of gold-silver-tellurium veins, as well as significant deposits of oil and gas, COa, asphalt, coal, and dimension stone. Mesozoic rocks contain limited amounts of limestone, gypsum, petrified wood, dinosaur remains, and clays. Tertiary rocks host ore deposits commonly associated with intrusive rocks, including platinum group elements, iron skarns, manganese, uranium and vanadium, molybdenum, polymetallic vein deposits, gold-silver- tellurium veins, and thorium-rare earth veins. Museum-quality quartz crystals in Lincoln County were formed in association with intrusive rocks in the Lincoln County porphyry belt. Industrial minerals in Tertiary rocks include fluorite, vein- and bedded-barite, caliche, limestone, and aggregate. Tertiary and Quaternary sediments host important placer deposits of gold and titanium, and minor silver, uranium occurrences, as well as important industrial commodities, including caliche, limestone and dolomite, and aggregate (sand). Quaternary basalt contains sub-ore-grade uranium, scoria, and clay deposits.

Mineral and energy resources of the Roswell Resource Area, East-Central New Mexico

USGS Publications Warehouse

Bartsch-Winkler, Susan B.; Donatich, Alessandro J.

1995-01-01

The sedimentary formations of the Roswell Resource Area have significant mineral and energy resources. Some of the pre-Pennsylvanian sequences in the Northwestern Shelf of the Permian Basin are oil and gas reservoirs, and Pennsylvanian rocks in Tucumcari Basin are reservoirs of oil and gas as well as source rocks for oil and gas in Triassic rocks. Pre-Permian rocks also contain minor deposits of uranium and vanadium, limestone, and gases. Hydrocarbon reservoirs in Permian rocks include associated gases such as carbon dioxide, helium, and nitrogen. Permian rocks are mineralized adjacent to the Lincoln County porphyry belt, and include deposits of copper, uranium, manganese, iron, polymetallic veins, and Mississippi-Valley-type lead-zinc. Industrial minerals in Permian rocks include fluorite, barite, potash, halite, polyhalite, gypsum, anhydrite, sulfur, limestone, dolomite, brine deposits (iodine and bromine), aggregate (sand), and dimension stone. Doubly terminated quartz crystals, called 'Pecos diamonds' and collected as mineral specimens, occur in Permian rocks along the Pecos River. Mesozoic sedimentary rocks are hosts for copper, uranium, and small quantities of gold-silver-tellurium veins, as well as significant deposits of oil and gas, carbon dioxide, asphalt, coal, and dimension stone. Mesozoic rocks contain limited amounts of limestone, gypsum, petrified wood, and clay. Tertiary rocks host ore deposits commonly associated with intrusive rocks, including platinum-group elements, iron skarns, manganese, uranium and vanadium, molybdenum, polymetallic vein deposits, gold-silver-tellurium veins, and thorium-rare-earth veins. Museum-quality quartz crystals are associated with Tertiary intrusive rocks. Industrial minerals in Tertiary rocks include fluorite, vein- and bedded-barite, caliche, limestone, and aggregate. Tertiary and Quaternary sediments host important placer deposits of gold and titanium, and occurrences of silver and uranium. Important industrial commodities include caliche, limestone and dolomite, and aggregate. Quaternary basalt contains sub-ore-grade uranium, scoria, and clay deposits.

Progress report on the Happy Jack mine, Which Canyon area, San Juan county, Utah

USGS Publications Warehouse

Trites, Albert F.; Chew, Randall T.

1954-01-01

The Happy Jack mine is in the White Canyon area, San Juan county, Utah. Production is from high-grade uranium deposits in the Shinarump conglomerate of the Triassic age. In this area the Shinarump beds range from about 16 to 40 feet in thickness and the lower part of these beds fills an east-trending channel this is note than 750 feet wide and 10 feet deep. The Shinarump conglomerate consists of beds of coarse- to fine-grained quartzose sandstone, conglomerate, siltstone, and claystone. Carbonized wood is abundant in these beds, and in the field it was classified as mineral charcoal and coal. Intra-Shinarump channels, cross-stratification, current lineation, and slumping and compaction structures have been recognized in the mine. Steeply dipping fractures have dominant trends in four directions -- N 65°W, N 60°E, N 85°E, and due north. Uranium occurs as bedded deposits, as replacement bodies in accumulations of "trash", and as replacements of larger fragments of wood. An "ore shoot" is formed where the three types of uranium deposits occur together; these ore shoots appear to be elongate masses with sharp boundaries. Uranium minerals include uraninite, sooty pitchblende(?), and the sulfate--betazippeite, johannite, and uranopilite. Associated with the uraninite are the sulfide minerals covellite, bornite, chalcopyritw, and pyrite. Galena and sphalerite have been found in close association with uranium minerals. The gaunge minerals include: limonite and hematite present in most of the sandstone beds throughout the deposit, jarosite that impregnates much of the sandstone in the outer parts of the mine workings, gypsum that fills many of the fractures, and barite that impregnates the sandstone in at least one part of the mine. Secondary copper minerals, mainly copper sulfates, occur throughout the mine, but most abundant near the adits in the outermost 30 feet of the workings. The minerals comprising the bulk of the country rock include quartz, feldspar, and clay minerals. The amount of uranium minerals deposited in a sandstone bed is believed to have been determined by the position of the bed in the channel, the permeability of the sandstone in the bed, and the amount of carbonized wood and plant remains within the bed. The beds considered most favorable for uranium deposition contain an abundance of claystone and siltstone both as matrix filling and as fragments and pebbles. Suggested exploration guides from uranium ore bodies include the following: (1) interbedded siltstone lenses, (2) claystone and siltstone cement and pabbles, (3) concentrations of "trash", (4) covelllite and bornite, (5) chalcopyrite, and (6) carbonized wood.

Comparison of the Ores of Swambo and Kalongwe with Shinkolobwe; LES GITES DE SWAMBO ET DE KALONGWE COMPARES A SHINKOLOBWE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Derriks, J.J.; Oosterbosch, R.

1959-10-31

Swambo is a small uraniferous deposit discovered recently to the east of Shimkolobwe. The mineralization found is localized in the breccia and the epontes'' of a transverse fault affecting a layer of the ore series. This layer is part of an anticline alignment which can be followed from Shinkolobwe to Kalongwe and the length of which is level with the schisto-dolomitric stratum. The discovery of the ore deposit was made hy the application of radiometric methods. A prelimiary series of borings showed that the usable mineralization extends 125 m under the surface. The development by mining has gone to themore » hydrostatic level. From a genetic viewpoint, the ore deposit is similar to that of Shinkolobwe, but it is less important. Kalongwe is a cupro-cobaltic ore deposit lying to the southeast of Kolwezi. The deposit is principally localized in a fault which intersects a small layer of the ore series. The greso-dolomitic stratum at the base of this series is impregnated with powdered black uranium oxides in the neighhorhood of the fault. The mineralization extends to 80 m of depth. The ore deposit was developed by mining to a depth of 42 m. The genesis of the deposit is comparable to that of Shinkolobwe, hat the Kalongwe ores are distinguished by the relative abundance of copper and the absence of nickel. (tr- auth)« less

The origin of the Avram Iancu U-Ni-Co-Bi-As mineralization, Băiţa (Bihor) metallogenic district, Bihor Mts., Romania

NASA Astrophysics Data System (ADS)

Zajzon, Norbert; Szentpéteri, Krisztián; Szakáll, Sándor; Kristály, Ferenc

2015-10-01

The Băiţa metallogenic district in the Bihor Mountains is a historically important mining area in Romania. Uranium mining took place between 1952 and 1998 from various deposits, but very little is known about the geology and mineralogy of these deposits. In this paper, we describe geology and mineralogy of uranium mineralization of the Avram Iancu uranium mine from waste dump samples collected before complete remediation of the site. Texturally and mineralogically complex assemblages of nickeline, cobaltite-gersdorffite solid solution, native Bi, Bi-sulfosalts, molybdenite, and pyrite-chalcopyrite-sphalerite occur with uraninite, "pitchblende," and brannerite in most of the ore samples. The association of nickel, cobalt, and arsenic with uranium is reminiscent of five-element association of vein type U-Ni-Co-Bi-As deposits; however, the Avram Iancu ores appear to be more replacement-type stratiform/stratabound. Avram Iancu ore samples contain multistage complex, skarn, uranium sulfide, arsenide assemblages that can be interpreted to have been formed in the retrograde cooling stages of the skarn hydrothermal system. This mineralizing system may have built-up along Upper Cretaceous-Paleogene "Banatite" intrusions of diorite-to-granite composition. The intrusions crosscut the underlying uraniferous Permian formations in the stacked NW-verging Biharia Nappe System. The mineralization forms stacked, multilayer replacement horizons, along carbonate-rich lithologies within the metavolcanic (tuffaceous) Muncel Series. Mineral paragenesis and some mineral chemistry suggest moderate-to-high <450, i.e., 350-310 °C, formation temperatures for the uranium sulfide stage along stratigraphically controlled replacement zones and minor veins. Uranium minerals formed abundantly in this early stage and include botryoidal, sooty and euhedral uraninite, brannerite, and coffinite. Later and/or lower-temperature mineral assemblages include heterogeneous, complexly zoned arsenide-sulfarsenide solid solutions associated with minute but abundant uranium minerals. Within the later arsenide-sulfarsenide mineral assemblage, there is great variation in Ni, Co, and S content with generally increasing arsenic content. Uranium minerals in this late-stage assemblage include very fine euhedral uraninite and brannerite inclusions in arsenide-sulfarsenide minerals. Native bismuth and Bi-sulfosalt krupkaite are observed in this As-S-rich assemblage strongly associated with cobaltite.

Uranium deposits in Grant County, New Mexico

USGS Publications Warehouse

Granger, Harry C.; Bauer, Herman L.; Lovering, Tom G.; Gillerman, Elliot

1952-01-01

The known uranium deposits of Grant county, N. Mex., are principally in the White Signal and Black Hawk districts. Both districts are within a northwesterly-trending belt of pre-Cambrian rocks, composed chiefly of granite with included gneisses, schists, and quartzites. Younger dikes and stocks intrude the pre-Cambrian complex. The White Signal district is on the southeast flanks of the Burro Mountains; the Black Hawk district is about 18 miles northwest of the town of White Signal. In the White Signal district the seconday uranium phosphates--autunite and torbernite--occur as fracture coatings and disseminations in oxidized parts of quartz-pyrite veins, and in the adjacent mafic dikes and granites; uraniferous limonite is common locally. Most of the known uraniferous deposits are less that 50 feet in their greatest dimension. The most promising deposits in the district are on the Merry Widow and Blue Jay claims. The richest sample taken from the Merry Widow mine contained more than 2 percent uranium and a sample from the Blue Jay property contained as much as 0.11 percent; samples from the other properties were of lower grade. In the Black Hawk district pitchblende is associated with nickel, silver, and cobalt minerals in fissure veins. The most promising properties in the Black Hawk district are the Black Hawk, Alhambra, and Rose mines. No uranium analyses from this district were available in 1951. There are no known minable reserves of uranium ore in either district, although there is some vein material at the Merry Widow mine of ore grade, if a market were available in the region.

The uranium deposit at the Yellow Canary claims, Daggett County, Utah

USGS Publications Warehouse

Wilmarth, V.R.; Vickers, R.C.; McKeown, F.A.; Beroni, E.P.

1952-01-01

The Yellow Canary claims uranium deposit is on the west side of Red Creek Canyon in the northern part of the Uinta Mountains, Daggett County, Utah. The claims have been developed by two adits, three open cuts, and several hundred deep of bulldozer trenches. No uranium ore has been produced from this deposit. The uranium deposit at the Yellow Canary claims is in the Red Creek quartzite of pre-Cambrian age. The formation is composed of intercalated beds of quartzite, hornblendite, garnet schist, staurolite schist, and quartz-mica schist and is intruded by diorite dikes. A thick unit of highly fractured white quatrzite at the top of the formation contains tyutamunite as coatings on fracture surfaces. The tyutamunite is associated with carnotite, volborthite, iron oxides, azurite, malachite, brochantite, and hyalite. The secondary uranium and vanadium minerals are believed to be alteration products of primary minerals. The uranium content of 15 samples from this property ranged from 0.000 to 0.57 percent.

Formation and resulfidization of a South Texas roll-type uranium deposit

USGS Publications Warehouse

Goldhaber, Martin B.; Reynolds, Richard L.; Rye, Robert O.

1979-01-01

Core samples from a roll type uranium deposit in Live Oak County, south Texas have been studied and results are reported for Se, Mo, FeS2 and organic-carbon distribution, sulfide mineral petrology, and sulfur isotopic composition of iron-disulfide phases. In addition, sulfur isotopic compositions of dissolved sulfate and sulfide from the modern ground water within the ore bearing sand have been studied. The suite of elements in the ore sand and their geometric relationships throughout the deposit are those expected for typical roll-type deposits with well-developed oxidation-reduction interfaces. However, iron-disulfide minerals are abundant in the altered tongue, demonstrating that this interval has been sulfidized after mineralization (resulfidized or rereduced). Iron disulfide minerals in the rereduced interval differ mineralogically and isotopically from those throughout the remainder of the deposit. The resulfidized sand contains dominantly pyrite that is enriched in 34S, whereas the sand beyond the altered tongue contains abundant marcasite that is enriched in the light isotope, 32S. Textural relationships between pyrite and marcasite help to establish relative timing of iron disulfide formation. In reduced rock outside the altered tongue, three distinct generations of iron disulfide are present. The oldest of these generations consists largely of pyrite with lesser amounts of marcasite. A major episode of marcasite formation contemporaneous with ore genesis postdates the oldest pyrite generation but predates a younger pyrite generation. Resulfidization probably led to the final pyrite stage recognized beyond the altered tongue. Stable isotope data establish that the source of sulfur for the resulfidization was fault-leaked H2S probably derived from the Edwards Limestone of Cretaceous age which underlies the deposit. The deposit formed in at least two stages: (1) a pre-ore process of host rock sulfidization which produced disseminated pyrite as the dominant iron disulfide phase; and (2) an ore-stage process which led to the development of the uranium roll with emplacement of the characteristic suite of minor and accessory elements and which produced abundant isotopically light marcasite. The host rock was modified by a post-ore stage of resulfidization which precipitated isotopically heavy pyrite. Sulfur isotopic compositions of sulfide and sulfate present in modern ground water within the host sand differ greatly from sulfur isotopic composition of iron disulfides formed during the resulfidization episode. Iron disulfide minerals formed from the sulfur species of modern ground water have not been unequivocally identified.

UNDERGROUND URANIUM MINING ON COLORADO PLATEAU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dare, W.L.

1958-10-31

The size and continuity of the Chinie ore bodies in the Big Indian district, Utah, have permitted mine operators in plan a more integrated development and mining system using larger and more specialized equipment. Thick ore and firm backs at the south end of the district than permitted room and pillar mining, using large drill jumbos send diesel-powered haulage equipment. The Gismo loader and draw-chute system has proved efficient. Driving the haulage- way below the stope level is an advantage when pillars are recovered. To the north, thinner ore with weaker backs favor retreat systems and smaller equipment. Here, themore » ore bodies are delineated by a grid system of drifts, send the ore recovered by panel, longwall, or similar mining methods, retreating toward the principal entry. Labor productivity ranges from 8 to 21 tons per man-shift, send direct mining send development costs, excluding initial development, ranges from 75 to 51 per ton. A unique system of mine development is in the Temple Mountain district, Utah, where the shallow Chinie deposits are mined through 36- inch diameter calyx drill holes. Using small diesel-powered ore buggies and bucket hoisting, ore in produced from the two largest mines at a rate of 4.1 tons per man-shift, at a direci cost of 15 a ton. Ambrosia Lake deposits range from 5 to 80 feet thick and occur from 350 to 1,000 feet below the surface. These mines are in development stages. Open, retreat, and top-slice sloping is planned. Adequate ventilation is essential in uranium mining since sufficient air must be coursed through the workings to maintain airborne radioactive concentration at tolerance levels send dilute exhaust gases where diesel-powered equipment is used. Uranium miners have found that radiometric scannning is a quick and efficient method for checking ths grade of the ore produced and in process of development. (auth)« less

Volcanogenic Uranium Deposits: Geology, Geochemical Processes, and Criteria for Resource Assessment

USGS Publications Warehouse

Nash, J. Thomas

2010-01-01

Felsic volcanic rocks have long been considered a primary source of uranium for many kinds of uranium deposits, but volcanogenic uranium deposits themselves have generally not been important resources. Until the past few years, resource summaries for the United States or the world generally include volcanogenic in the broad category of 'other deposits' because they comprised less than 0.5 percent of past production or estimated resources. Exploration in the United States from the 1940s through 1982 discovered hundreds of prospects in volcanic rocks, of which fewer than 20 had some recorded production. Intensive exploration in the late 1970s found some large deposits, but low grades (less than about 0.10 percent U3O8) discouraged economic development. A few deposits in the world, drilled in the 1980s and 1990s, are now known to contain large resources (>20,000 tonnes U3O8). However, research on ore-forming processes and exploration for volcanogenic deposits has lagged behind other kinds of uranium deposits and has not utilized advances in understanding of geology, geochemistry, and paleohydrology of ore deposits in general and epithermal deposits in particular. This review outlines new ways to explore and assess for volcanogenic deposits, using new concepts of convection, fluid mixing, and high heat flow to mobilize uranium from volcanic source rocks and form deposits that are postulated to be large. Much can also be learned from studies of epithermal metal deposits, such as the important roles of extensional tectonics, bimodal volcanism, and fracture-flow systems related to resurgent calderas. Regional resource assessment is helped by genetic concepts, but hampered by limited information on frontier areas and undiscovered districts. Diagnostic data used to define ore deposit genesis, such as stable isotopic data, are rarely available for frontier areas. A volcanic environment classification, with three classes (proximal, distal, and pre-volcanic structures), permits use of geologic features on 1:500,000 to 1:100,000 scale maps. Geochemical databases for volcanic rocks are postulated to be more effective than databases for stream sediments or surface radioactivity, both of which tend to be inconsistent because of variable leaching of uranium from soils. Based on empirical associations, spatial associations with areas of wet paleoclimate, adjacent oil and gas fields, or evaporite beds are deemed positive. Most difficult to estimate is the location of depositional traps and reduction zones, in part because they are mere points at regional scale. Grade and tonnage data are reviewed and discussed for 32 deposits in the world. Experience of mining engineers and geologists in Asia suggests that tonnages could be higher than presently known in the Western Hemisphere. Geological analysis, and new data from Asia, suggest a typical or median deposit tonnage of about 5,000 tonnes U3O8, and an optimistic forecast of discoveries in the range of 5,000 to 20,000 tonnes U3O8. The likely grade of undiscovered deposits could be about 0.15 percent U3O8 , based on both western and eastern examples. Volcanic terrane is under-explored, relative to other kinds of uranium deposits, and is considered a favorable frontier area for new discoveries.

Geochemistry of vanadium in an epigenetic, sandstone-hosted vanadium- uranium deposit, Henry Basin, Utah

USGS Publications Warehouse

Wanty, R.B.; Goldhaber, M.B.; Northrop, H.R.

1990-01-01

The epigenetic Tony M vanadium-uranium orebody in south-central Utah is hosted in fluvial sandstones of the Morrison Formation (Upper Jurassic). Measurements of the relative amounts of V+3 and V +4 in ore minerals show that V+3 is more abundant. Thermodynamic calculations show that vanadium was more likely transported to the site of mineralization as V+4. The ore formed as V+4 was reduced by hydrogen sulfide, followed by hydrolysis and precipitation of V+3 in oxide minerals or chlorite. Uranium was transported as uranyl ion (U+6), or some complex thereof, and reduced by hydrogen sulfide, forming coffinite. Detrital organic matter in the rocks served as the carbon source for sulfate-reducing bacteria. Vanadium most likely was derived from the dissolution of iron-titanium oxides. Uranium probably was derived from the overlying Brushy Basin Member of the Morrison Formation. Previous studies have shown that the ore formed at the density-stratified interface between a basinal brine and dilute meteoric water. The mineralization processes described above occurred within the mixing zone between these two fluids. -from Authors

Uranium content and leachable fraction of fluorspars

USGS Publications Warehouse

Landa, E.R.; Councell, T.B.

2000-01-01

Much attention in the radiological health community has recently focused on the management and regulation of naturally occurring radioactive materials. Although uranium-bearing minerals are present in a variety of fluorspar deposits, their potential consideration as naturally occurring radioactive materials has received only limited recognition. The uranium content of 28 samples of acid- and cryolite-grade (>97% CaF2) fluorspar from the National Defense Stockpile was found to range from 120 to 24,200 ??g kg-1, with a mean of 2,145 ??g kg-1. As a point of comparison, the average concentration of uranium in the upper crust of the earth is about 2,500 ??g kg-1. Leachability of this uranium was assessed by means of the Toxicity Characteristic Leaching Procedure (TCLP). The TCLP extractable fraction ranged from 1 to 98%, with a mean of 24% of the total uranium. The typically low concentrations of uranium seen in these materials probably reflects the removal of uranium-bearing mineral phases during the beneficiation of the crude fluorspar ore to achieve industrial specifications. Future NORM studies should examine crude fluorspar ores and flotation tailings.

Uranium mineralization in fluorine-enriched volcanic rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burt, D.M.; Sheridan, M.F.; Bikun, J.

1980-09-01

Several uranium and other lithophile element deposits are located within or adjacent to small middle to late Cenozoic, fluorine-rich rhyolitic dome complexes. Examples studied include Spor Mountain, Utah (Be-U-F), the Honeycomb Hills, Utah (Be-U), the Wah Wah Mountains, Utah (U-F), and the Black Range-Sierra Cuchillo, New Mexico (Sn-Be-W-F). The formation of these and similar deposits begins with the emplacement of a rhyolitic magma, enriched in lithophile metals and complexing fluorine, that rises to a shallow crustal level, where its roof zone may become further enriched in volatiles and the ore elements. During initial explosive volcanic activity, aprons of lithicrich tuffsmore » are erupted around the vents. These early pyroclastic deposits commonly host the mineralization, due to their initial enrichment in the lithophile elements, their permeability, and the reactivity of their foreign lithic inclusions (particularly carbonate rocks). The pyroclastics are capped and preserved by thick topaz rhyolite domes and flows that can serve as a source of heat and of additional quantities of ore elements. Devitrification, vapor-phase crystallization, or fumarolic alteration may free the ore elements from the glassy matrix and place them in a form readily leached by percolating meteoric waters. Heat from the rhyolitic sheets drives such waters through the system, generally into and up the vents and out through the early tuffs. Secondary alteration zones (K-feldspar, sericite, silica, clays, fluorite, carbonate, and zeolites) and economic mineral concentrations may form in response to this low temperature (less than 200 C) circulation. After cooling, meteoric water continues to migrate through the system, modifying the distribution and concentration of the ore elements (especially uranium).« less

Physical exploration for uranium during 1951 in the Silver Reef district, Washington County, Utah

USGS Publications Warehouse

Stugard, Frederick

1954-01-01

During 1951 a joint exploration program of the most promising uraniferous areas in the Silver Reef district was made by the U.S. Geological Survey and the U.S. atomic Energy Commission. A U.S. Bureau of Mines drill crew, on contract to the Atomic Energy Commission, did 2,450 feet of diamond drilling under the geological supervision of the U.S. Geological Survey. The purpose of the drilling was to delineate broadly the favorable ground for commercial development of the uranium deposits. Ten drill holes were located around Pumpkin Point, which is the northeastern end of Buckeye Reef, to probe for extensions of small ore sheets mined on the Point in fine-grained sandstones of the Chinle formation. Three additional holes were located around Tecumseh Hill to probe for extensions of the small showings of uranium-bearing rocks of Buckeye Reef. Only one trace of uranium mineral was detected in the 13 drill holes by logging of drill cores, gamma-ray logging of the holes, and analysis of many core splits from favorable lithology. Extensive traversing with Geiger counters throughout the district and detailed geologic mapping of areas on Buckeye Reef and on East Reef indicate that the chances of discovering significant uranium deposits in the Silver Reef district are very poor, because of: highly variable lithology, closely faulted structure, and obliteration of the shallow uranium-bearing lenses by silver mining. Most of the available ore in the district was in the Pumpkin Point area and has been mined during 1950 to 1953. No ore reserves can be computed for the district before further development work. The most favorable remaining area in the district is now being explored by the operators with Atomic Energy Commission supervision.

Uranium deposits in the Eureka Gulch area, Central City district, Gilpin County, Colorado

USGS Publications Warehouse

Sims, P.K.; Osterwald, F.W.; Tooker, E.W.

1954-01-01

The Eureka Gulch area of the Central City district, Gilpin County, Colo., was mined for ores of gold, silver, copper, lead, and zinc; but there has been little mining activity in the area since World War I. Between 1951 and 1953 nine radioactive mine dumps were discovered in the area by the U.S. Geological Survey and by prospectors. the importance of the discoveries has not been determined as all but one of the mines are inaccessible, but the distribution, quantity, and grade of the radioactive materials found on the mine dumps indicate that the area is worth of additional exploration as a possible source of uranium ore. The uranium ans other metals are in and near steeply dipping mesothermal veins of Laramide age intrusive rocks. Pitchblende is present in at least four veins, and metatorbernite, associated at places with kosolite, is found along two veins for a linear distance of about 700 feet. The pitchblends and metatorbernite appear to be mutually exclusive and seem to occur in different veins. Colloform grains of pitchblende were deposited in the vein essentially contemporaneously with pyrite. The pitchblende is earlier in the sequence of deposition than galena and sphalerite. The metatorbernite replaces altered biotite-quartz-plagioclase gneiss and altered amphibolite, and to a lesser extent forms coatings on fractures in these rocks adjacent to the veins; the kasolite fills vugs in highly altered material and in altered wall rocks. Much of the pitchblende found on the dumps has been partly leached subsequent to mining and is out of equilibrium. Selected samples of metatorbernite-bearing rock from one mine dump contain as much as 6.11 percent uranium. The pitchblende is a primary vein mineral deposited from uranium-bearing hydrothermal solutions. The metatorbernite probably formed by oxidation, solution, and transportation of uranium from primary pitchblende, but it may be a primary mineral deposited directly from fluids of different composition from these that deposited pitchblende.

Preliminary study of favorability for uranium resources in Juab County, Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leedom, S.H.; Mitchell, T.P.

1978-02-01

The best potential for large, low-grade uranium deposits in Juab County is in the hydrothermally altered vitric tuffs of Pliocene age. The lateral extent of the altered tuffs may be determined by subsurface studies around the perimeter of the volcanic centers in the Thomas Range and the Honeycomb Hills. Because the ring-fracture zone associated with collapse of the Thomas caldera was a major control for hydrothermal uranium deposits, delineation of the northern and eastern positions of the ring-fracture zone is critical in defining favorable areas for uranium deposits. A small, medium-grade ore deposit in tuffaceous sand of Pliocene age atmore » the Yellow Chief mine in Dugway Dell is unique in origin, and the probability of discovering another deposit of this type is low. A deposit of this type may be present under alluvial cover in the northwestern Drum Mountains along the southern extension of the ring-fracture zone of the Thomas caldera. Festoonlike iron oxide structures and uranium deposition within permeable sandstone horizons indicate that the Yellow Chief deposit was formed by recent ground-water circulation. Granitic intrusive rocks in the Deep Creek Range and in Desert Mountain contain isolated epigenetic vein-type deposits. These rocks could be a source of arkosic sediments buried in adjacent valleys. The Pleistocene lacustrine sediments and playa lake brines may contain concentrations of uranium leached from uranium-rich rocks.« less

Field, model, and computer simulation study of some aspects of the origin and distribution of Colorado Plateau-type uranium deposits

USGS Publications Warehouse

Ethridge, F.G.; Sunada, D.K.; Tyler, Noel; Andrews, Sarah

1982-01-01

Numerous hypotheses have been proposed to account for the nature and distribution of tabular uranium and vanadium-uranium deposits of the Colorado Plateau. In one of these hypotheses it is suggested that the deposits resulted from geochemical reactions at the interface between a relatively stagnant groundwater solution and a dynamic, ore-carrying groundwater solution which permeated the host sandstones (Shawe, 1956; Granger, et al., 1961; Granger, 1968, 1976; and Granger and Warren, 1979). The study described here was designed to investigate some aspects of this hypothesis, particularly the nature of fluid flow in sands and sandstones, the nature and distribution of deposits, and the relations between the deposits and the host sandstones. The investigation, which was divided into three phases, involved physical model, field, and computer simulation studies. During the initial phase of the investigation, physical model studies were conducted in porous-media flumes. These studies verified the fact that humic acid precipitates could form at the interface between a humic acid solution and a potassium aluminum sulfate solution and that the nature and distribution of these precipitates were related to flow phenomena and to the nature and distribution of the host porous-media. During the second phase of the investigation field studies of permeability and porosity patterns in Holocene stream deposits were investigated and the data obtained were used to design more realistic porous media models. These model studies, which simulated actual stream deposits, demonstrated that precipitates possess many characteristics, in terms of their nature and relation to host sandstones, that are similar to ore deposits of the Colorado Plateau. The final phase of the investigation involved field studies of actual deposits, additional model studies in a large indoor flume, and computer simulation studies. The field investigations provided an up-to-date interpretation of the depositional environments of the host sandstones in the Slick Rock District and data on the nature and distribution of the ore deposits which are found to be directly related to the architecture of the host sandstones which acted as conduits for the transport of mineralized groundwaters. Large-scale model studies, designed to simulate Grants Mineral Belt deposits, demonstrated that precipitates had characteristics similar to those of actual uranium deposits and data obtained from these studies strongly supported the hypothesis that the ores formed soon after deposition of the host sandstones and that their distribution was largely controlled by permeability and porosity patterns established at the time of deposition of the host sandstones. A numerical model was developed during the second and third stages of the investigation that can predict favorable locations for mineralization given sufficient data on porosity, hydraulic conductivity, the distribution and thickness of sandstone hosts, and an estimate of the initial hydrologic conditions. The model was successfully tested using data from the Slick Rock District.

A precise 232Th-208Pb chronology of fine-grained monazite: Age of the Bayan Obo REE-Fe-Nb ore deposit, China

USGS Publications Warehouse

Wang, Jingyuan; Tatsumoto, M.; Li, X.; Premo, W.R.; Chao, E.C.T.

1994-01-01

We have obtained precise Th-Pb internal isochron ages on monazite and bastnaesite for the world's largest known rare earth elements (REE)-Fe-Nb ore deposit, the Bayan Obo of Inner Mongolia, China. The monazite samples, collected from the carbonate-hosted ore zone, contain extremely small amounts of uranium (less than 10 ppm) but up to 0.7% ThO2. Previous estimates of the age of mineralization ranged from 1.8 to 0.255 Ga. Magnetic fractions of monazite and bastnaesite samples (<60-??m size) showed large ranges in 232Th 204Pb values (900-400,000) and provided precise Th-Pb internal isochron ages for paragenetic monazite mineralization ranging from 555 to 398 Ma within a few percent error (0.8% for two samples). These results are the first indication that REE mineralization within the giant Bayan Obo ore deposit occurred over a long period of time. The initial lead isotopic compositions (low 206Pb 204Pb and high 208Pb 204Pb) and large negative ??{lunate}Nd values for Bayan Obo ore minerals indicate that the main source(s) for the ores was the lower crust which was depleted in uranium, but enriched in thorium and light rare earth elements for a long period of time. Zircon from a quartz monzonite, located 50 km south of the ore complex and thought to be related to Caledonian subduction, gave an age of 451 Ma, within the range of monazite ages. Textural relations together with the mineral ages favor an epigenetic rather than a syngenetic origin for the orebodies. REE mineralization started around 555 Ma (disseminated monazite in the West, the Main, and south of the East Orebody), but the main mineralization (banded ores) was related to the Caledonian subduction event ca. 474-400 Ma. ?? 1994.

Wind Transport of Radionuclide- Bearing Dust, Peña Blanca, Chihuahua, Mexico

NASA Astrophysics Data System (ADS)

Velarde, R.; Goodell, P. C.; Gill, T. E.; Arimoto, R.

2007-05-01

This investigation evaluates radionuclide fractionation during wind erosion of high-grade uranium ore storage piles at Peña Blanca (50km north of Chihuahua City), Chihuahua, Mexico. The aridity of the local environment promotes dust resuspension by high winds. Although active operations ceased in 1983, the Peña Blanca mining district is one of Mexico`s most important uranium ore reserves. The study site contains piles of high grade ore, left loose on the surface, and separated by the specific deposits from which they were derived (Margaritas, Nopal I, and Puerto I). Similar locations do not exist in the United States, since uranium mining sites in the USA have been reclaimed. The Peña Blanca site serves as an analog for the Yucca Mountain project. Dust deposition is collected at Peña Blanca with BSNE sediment catchers (Fryrear, 1986) and marble dust traps (Reheis, 1999). These devices capture windblown sediment; subsequently, the sample data will help quantify potentially radioactive short term field sediment loss from the repository surface and determine sediment flux. Aerosols and surface materials will be analyzed and radioactivity levels established utilizing techniques such as gamma spectroscopy. As a result, we will be able to estimate how much radionuclide contaminated dust is being transported or attached geochemically to fine grain soils or minerals (e.g., clays or iron oxides). The high-grade uranium-bearing material is at secular equilibrium, thus the entire decay series is present. Of resulting interest is not only the aeolian transport of uranium, but also of the other daughter products. These studies will improve our understanding of geochemical cycling of radionuclides with respect to sources, transport, and deposition. The results may also have important implications for the geosciences and homeland security, and potential applications to public health. Funding for this project is provided in part via a NSF grant to Arimoto.

Age of uranium mineralization at the Jabiluka and Ranger deposits, Northern Territory, Australia: New U- Pb isotope evidence.

USGS Publications Warehouse

Ludwig, K. R.; Grauch, R.I.; Nutt, C.J.; Nash, J.T.; Frishman, D.; Simmons, K.R.

1987-01-01

The Ranger and Jabiluka uranium deposits are the largest in the Alligator Rivers uranium field, which contains at least 20% of the world's low-cost uranium reserves. Ore occurs in early Proterozoic metasediments, below an unconformity with sandstones of the 1.65 b.y.-old Kombolgie Formation. This study has used U-Pb isotope data from a large number of whole-rock drill core samples with a variety of mineral assemblages and textures. Both Ranger and Jabiluka reflect a common, profound isotopic disturbance at about 400 to 600 m.y. This disturbance, which was especially pronounced at Jabiluka, may correspond to the development of basins and associated basalt flows to the W and SW.-from Authors

The Problem of Preconcentration of Uranium Ores by Physical Processes; LES PROBLEMES DE LA PRECONCENTRATION DES MINERAIS D'URANIUM PAR VOIE PHYSIQUE. LE TRIAGE ELECTRONIQUE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vuchot, L.; Ginocchio, A. et al.

1959-10-31

As uranium ores, like most other ores, are not definite substances which can be treated directly for the production of the metal, the ores must be concentrated. The common physical processes used for all ores, such as sieving, gravimetric separation, flotation, electromagnetic separation, and electrostatic separation, are applicable to the beneficiation of uranium. The radioactivity of uranium ores has led to a radiometric method for the concentration. This method is described in detail. As an example, the preconcentration of Forez ores is discussed. (J.S.R.)

Isotopic evidence for reductive immobilization of uranium across a roll-front mineral deposit

DOE PAGES

Brown, Shaun T.; Basu, Anirban; Christensen, John N.; ...

2016-05-20

We use uranium (U) isotope ratios to detect and quantify the extent of natural U reduction in groundwater across a roll front redox gradient. Our study was conducted at the Smith Ranch-Highland in situ recovery (ISR) U mine in eastern Wyoming, USA, where economic U deposits occur in the Paleocene Fort Union formation. To evaluate the fate of aqueous U in and adjacent to the ore body, we investigated the chemical composition and isotope ratios of groundwater samples from the roll-front type ore body and surrounding monitoring wells of a previously mined area. The 238U/ 235U of groundwater varies bymore » approximately 3‰ and is correlated with U concentrations. Fluid samples down-gradient of the ore zone are the most depleted in 238U and have the lowest U concentrations. Activity ratios of 234U/ 238U are ~5.5 up-gradient of the ore zone, ~1.0 in the ore zone, and between 2.3 and 3.7 in the down-gradient monitoring wells. High-precision measurements of 234U/ 238U and 238U/ 235U allow for development of a conceptual model that evaluates both the migration of U from the ore body and the extent of natural attenuation due to reduction. We find that the premining migration of U down-gradient of the delineated ore body is minimal along eight transects due to reduction in or adjacent to the ore body, whereas two other transects show little or no sign of reduction in the down-gradient region. Lastly, these results suggest that characterization of U isotopic ratios at the mine planning stage, in conjunction with routine geochemical analyses, can be used to identify where more or less postmining remediation will be necessary.« less

U-Pb dating of uranium deposits in collapse breccia pipes of the Grand Canyon region

USGS Publications Warehouse

Ludwig, K. R.; Simmons, K.R.

1992-01-01

Two major periods of uranium mineralization are indicated by U-Pb isotope dating of uranium ores from collapse breccia pipes in the Grand Canyon region, northern Arizona. The Hack 2 and 3, Kanab North, and EZ 1 and 2 orebodies apparently formed in the interval of 200 ?? 20 Ma, similar to ages inferred for strata-bound, Late Triassic-hosted uranium deposits in southern Utah and northern Arizona. Samples from the Grand Canyon and Pine Nut pipes, however, indicate a distinctly older age of about 260 Ma. The clustering in ages for a variety of uranium deposits at about the age of the lower part of the Chinle Formation (Late Triassic) suggests that uranium in these deposits may have been derived by leaching from volcanic ash in the Chinle and mobilized by ground-water movement. Pb isotope ratios of galenas in mineralized pipes are more radiogenic than those of sulfides from either uranium-poor pipes or occurrences away from pipes. Fluids which passed through the pipes had interacted with the Proterozoic basement, possibly through the vertical fractures which influenced the location and evolution of the pipes themselves. -from Authors

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 Protection of Environment... SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.30 Applicability; description of the uranium, radium and vanadium ores subcategory. The provisions of this subpart C are applicable to...

Uranium-bearing breccia pipes of northwestern Arizona - an overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chenoweth, W.L.

During the 1950s and 1960s, the uranium deposits in breccia pipes of the Grand Canyon region were regarded as geologic curiosities. Today this area is the site of numerous exploration projects for ore-bearing pipes. The classic example of the older mines is the Orphan Lode, a patented claim within Grand Canyon National Park. Between 1956 and 1969, this deposit produced 4.26 million lb U/sub 3/O/sub 8/. Exploration since the mid-1970s has developed numerous new deposits in the Grand Canyon region. The Hack 1, 2, and 3, Pigeon, Kanab North, Canyon, and Pinenut deposits are, or will be, mined. The pipesmore » are circular and originated by dissolution of the Mississippian Redwall Limestone and collapse of the overlying strata. Uraninite ore occurs in both the pipe fill and in association with the peripheral shear zone. The principal host rocks are the Coconino Sandstone, Hermit Shale, and Esplanade Sandstone. Although small (3 to 5 million lb U/sub 3/O/sub 8/), the high grade (60 to 70% U/sub 3/O/sub 8/) of the deposits makes the pipes attractive exploration targets.« less

Biogeochemical prospecting for uranium with conifers: results from the Midnite Mine area, Washington

USGS Publications Warehouse

Nash, J. Thomas; Ward, Frederick Norville

1977-01-01

The ash of needles, cones, and duff from Ponderosa pine (Pinus ponderosa Laws) growing near uranium deposits of the Midnite mine, Stevens County, Wash., contain as much as 200 parts per million (ppm) uranium. Needle samples containing more than 10 ppm uranium define zones that correlate well with known uranium deposits or dumps. Dispersion is as much as 300 m but generally is less. Background is about 1 ppm. Tree roots are judged to be sampling ore, low-grade uranium halo, or ground water to a depth of about 15 m. Uptake of uranium by Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) needles appears to be about the same as by Ponderosa pine needles. Cones and duff are generally enriched in uranium relate to needles. Needles, cones, and duff are recommended as easily collected, uncomplicated sample media for geochemical surveys. Samples can be analyzed by standard methods and total cost per sample kept to about $6.

Localization of uranium minerals in channel sediments at the base of the Shinarump conglomerate, Monument Valley, Arizona

USGS Publications Warehouse

Witkind, I.J.

1954-01-01

formation (Permian) to the Salt Wash member of the Morrison formation (Jurassic), The dominant structural element of the area is the Monument upwarp, a arge asymmetrical anticline whose northern end is near the junction of the Green and Colorado Rivers in Utah, and whose southern end disappears near Kayenta, Ariz. Asymmetrical anticlines with steeply dipping east flanks and gently dipping west flanks are superimposed on the upwarp. These subsidiary structures trend north. The uranium ore bodies are localized in conglomeratic sandstone of the Upper Triassic Shinarump conglomerate that fills channels scoured in the underlying Lower and Middle (?) Triassic Moenkopi formation. These channels range from relatively narrow and shallow ones 15 feet wide and 10 feet deep to much broader and deeper ones 2,300 feet wide and 70 feet deep. Two types of channels can be distinguished-r-a short-type less than 2 miles Iong 5 and a long-type traceable for distances greater than 2 miles Plant matter in the form of trees, branches,'and twigs was deposited with Shinarump sediments in the channels. It is suggested that when the Shinarump conglomerate was invaded by mineralizing solutions the uranium ore was deposited primarily in localities formerly occupied by the plant material. Further, it is suggested that the short channels are more likely to have ore accumulations than long channels.

Diversity, metal resistance and uranium sequestration abilities of bacteria from uranium ore deposit in deep earth stratum.

PubMed

Islam, Ekramul; Sar, Pinaki

2016-05-01

Metal resistance and uranium (U) sequestration abilities of bacteria residing in subsurface U ore was investigated using 122 pure culture strains isolated through enrichment. The cumulative frequencies of isolates resistant to each metal tested were as follows: As(V), 74%; Zn, 58%; Ni, 53%; Cd, 47%; Cr(VI), 41%; Co, 40%; Cu, 20%; and Hg, 4%. 16S rRNA gene analysis revealed that isolated bacteria belonged to 14 genera with abundance of Arthrobacter, Microbacterium, Acinetobacter and Stenotrophomonas. Cobalt did not interfere with the growth of most of the bacterial isolates belonging to different groups while U allowed growth of four different genera of which Stenotrophomonas and Microbacterium showed high U tolerance. Interestingly, tolerance to Ni, Zn, Cu, and Hg was observed only in Microbacterium, Arthrobacter, Paenibacillus¸ and Acinetobacter, respectively. However, Microbacterium was found to be dominant when isolated from other five different metal enrichments including U. Uranium removal study showed that 84% of the test bacteria could remove more than 50mgUg(-1) dry weight from 80 or 160mgL(-1) U within 48h. In general, Microbacterium, Arthrobacter and Acinetobacter could remove a higher amount of U. High resolution transmission electron microscopy (HRTEM) study of U exposed cells revealed that accumulated U sequestered mostly around the cell periphery. The study highlights that indigenous U ore deposit bacteria have the potential to interact with U, and thus could be applied for bioremediation of U contaminated sites or wastes. Copyright © 2016 Elsevier Inc. All rights reserved.

Distribution of radioactive isotopes in rock and ore of Arkhangelskaya pipe from the Arkhangelsk diamond province

NASA Astrophysics Data System (ADS)

Kiselev, G. P.; Yakovlev, E. Yu.; Druzhinin, S. V.; Galkin, A. S.

2017-09-01

The contents of radioactive elements and the uranium isotopic composition of kimberlite in the Arkhangelskaya pipe at the M.V. Lomonosov deposit and of nearby country rocks have been studied. A surplus of 234U isotope has been established in rocks from the near-pipe space. The high γ = 234U/238U ratio is controlled by the geological structure of the near-pipe space. A nonequilibrium uranium halo reaches two pipe diameters in size and can be regarded as a local ore guide for kimberlite discovery. The rocks in the nearpipe space are also characterized by elevated or anomalous U, Th, and K contents with respect to the background.

Yellowcake National Park

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagget, D.

Exploration for and mining of uranium ore is going on within 10 miles of the Grand Canyon National Park. The current rush started in 1980, when a Denver-based company, Energy Fuels Nuclear, took over a claim in Hack Canyon and uncovered a very rich deposit of uranium ore. Recent explorations have resulted in some 1300 claims in the area around the Grand Canyon, many of them in the Arizona Strip, the land between the Canyon and Utah. The center of current controversy is the 1872 Mining Law. Replacement of the law with a leasing system similar to that used formore » leasable minerals such as coal, oil shale, oil and gas, potash, and phosphate is advocated. 1 figure.« less

Distribution of calcretes and gypcretes in southwestern United States and their uranium favorability, based on a study of deposits in Western Australia and South West Africa (Namibia)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlisle, D.; Merifield, P.M.; Orme, A.R.

Calcrete, dolocrete, and gypcrete carnotite are abundant in western Australia and Namib Desert, although only a few are of ore grade. The geology of these deposits are described. A genetic classification of calcretes emphasizing uranium favorability was developed, based on the distinction between pedogenic and nonpedogenic processes. Similarities between western Australia and South West Africa give support for the conclusions that lateral transport of U in groundwater is essential to ore deposition and that bedrock barriers or constrictions which narrow the channel of subsurface flow or force the water close to the land surface, greatly favor the formation of uraniferousmore » calcretes. Criteria for uranium favorability deduced from the Australian and South West African studies were applied in a preliminary way to the southern Basin and Range Province of U.S. The procedure is to search for areas in which nonpedogenic calcrete or gypcrete may have developed. A caliche distribution map was compiled from soil survey and field data. Many areas were visited and some of the more interesting are described briefly, including parts of Clark County, Nevada, with occurrences of carnotite in calcrete. (DLC)« less

Geology and ore deposits of the McDermitt Caldera, Nevada-Oregon

USGS Publications Warehouse

Rytuba, James J.

1976-01-01

The McDermitt caldera is a Miocene collapse structure along the Nevada-Oregon border. The oval-shaped caldera is bounded by arcuate normal faults on the north and south and by rhyolite ring domes on the west. Precollapse ash-flow tuffs exposed within the south caldera rim consist of three cooling units and are peralkaline in composition. Refractive indexes of nonhydrated glasses from basal vitrophyres of the. units range from 1.493 to 1.503 and are typical of comendites. Post-collapse intracaldera rocks consist of tuffaceous lake sediments, rhyolite flows and domes, and ash-flow tuffs. Within the caldera are the mercury mines of Bretz, Cordero, McDermitt, Opalite, and Ruja and the Moonlight uranium mine. The mercury mines are adjacent to ring fracture faults, and the uranium mine and other uranium occurrences are located within rhyolite ring domes. Fluid inclusions in quartz indicate a deposition temperature of 340?C for the uranium deposit and 200?C for the mercury deposits. The mercury deposits formed at shallow depth by replacement of lakebed sediments and volcanic rocks.

Numerical simulation of migration behavior of uranium ore dust particles in the human respiratory tract

NASA Astrophysics Data System (ADS)

Ye, Yong-jun; Yin, An-song; Li, Zhi; Lei, Bo; Ding, De-xin

2017-04-01

There is a certain concentration of radioactive dust particles in the air of workplace of underground uranium mines. Some small diameter particles will pass through the masks and enter the respiratory tract which will cause radiation damage to the human body. In order to study deposition regularity of uranium dust in the human respiratory tract, in this paper, we firstly use the RNG turbulence model to simulate the gas flow field in the human respiratory tract Z0 ∼ Z3 level under different respiratory intensity. Then we use DPM discrete phase model to simulate the concentration, particle size distribution, deposition rate and deposition share of uranium dust particles after being filtered through the masks in the human respiratory tract Z0 to Z3 bronchus. According to the simulation results, we have got the following conclusions: the particles’ number concentration of uranium dust after being filtered through the mask in the human respiratory tract basically decreases with the increasing of particle size under different respiratory intensities on the environment of uranium mine. In addition, the intensity of respiration and the mass concentration of particles have an important influence on the deposition rate and the deposition of particles in the respiratory tract.

Uranium transport in the Walker River Basin, California and Nevada

USGS Publications Warehouse

Benson, L.V.; Leach, D.L.

1979-01-01

During the summer of 1976 waters from tributaries, rivers, springs and wells were sampled in the Walker River Basin. Snow and sediments from selected sites were also sampled. All samples were analyzed for uranium and other elements. The resulting data provide an understanding of the transport of uranium within a closed hydrologic basin as well as providing a basis for the design of geochemical reconnaissance studies for the Basin and Range Province of the Western United States. Spring and tributary data are useful in locating areas containing anomalous concentrations of uranium. However, agricultural practices obscure the presence of known uranium deposits and render impossible the detection of other known deposits. Uranium is extremely mobile in stream waters and does not appear to sorb or precipitate. Uranium has a long residence time (2500 years) in the open waters of Walker Lake; however, once it crosses the sediment-water interface, it is reduced to the U(IV) state and is lost from solution. Over the past two million years the amount of uranium transported to the terminal point of the Walker River system may have been on the order of 4 ?? 108 kg. This suggests that closed basin termini are sites for significant uranium accumulations and are, therefore, potential sites of uranium ore deposits. ?? 1979.

10 CFR 40.23 - General license for carriers of transient shipments of natural uranium other than in the form of...

Code of Federal Regulations, 2012 CFR

2012-01-01

... natural uranium other than in the form of ore or ore residue. 40.23 Section 40.23 Energy NUCLEAR... carriers of transient shipments of natural uranium other than in the form of ore or ore residue. (a) A... than in the form of ore or ore residue, in amounts exceeding 500 kilograms. (b)(1) Persons generally...

10 CFR 40.23 - General license for carriers of transient shipments of natural uranium other than in the form of...

Code of Federal Regulations, 2011 CFR

2011-01-01

... natural uranium other than in the form of ore or ore residue. 40.23 Section 40.23 Energy NUCLEAR... carriers of transient shipments of natural uranium other than in the form of ore or ore residue. (a) A... than in the form of ore or ore residue, in amounts exceeding 500 kilograms. (b)(1) Persons generally...

10 CFR 40.23 - General license for carriers of transient shipments of natural uranium other than in the form of...

Code of Federal Regulations, 2013 CFR

2013-01-01

... natural uranium other than in the form of ore or ore residue. 40.23 Section 40.23 Energy NUCLEAR... carriers of transient shipments of natural uranium other than in the form of ore or ore residue. (a) A... than in the form of ore or ore residue, in amounts exceeding 500 kilograms. (b)(1) Persons generally...

10 CFR 40.23 - General license for carriers of transient shipments of natural uranium other than in the form of...

Code of Federal Regulations, 2014 CFR

2014-01-01

... natural uranium other than in the form of ore or ore residue. 40.23 Section 40.23 Energy NUCLEAR... carriers of transient shipments of natural uranium other than in the form of ore or ore residue. (a) A... than in the form of ore or ore residue, in amounts exceeding 500 kilograms. (b)(1) Persons generally...

Inherently safe in situ uranium recovery

DOEpatents

Krumhansl, James L; Brady, Patrick V

2014-04-29

An in situ recovery of uranium operation involves circulating reactive fluids through an underground uranium deposit. These fluids contain chemicals that dissolve the uranium ore. Uranium is recovered from the fluids after they are pumped back to the surface. Chemicals used to accomplish this include complexing agents that are organic, readily degradable, and/or have a predictable lifetime in an aquifer. Efficiency is increased through development of organic agents targeted to complexing tetravalent uranium rather than hexavalent uranium. The operation provides for in situ immobilization of some oxy-anion pollutants under oxidizing conditions as well as reducing conditions. The operation also artificially reestablishes reducing conditions on the aquifer after uranium recovery is completed. With the ability to have the impacted aquifer reliably remediated, the uranium recovery operation can be considered inherently safe.

Geographical coincidence of high heat flow, high seismicity, and upwelling, with hydrocarbon deposits, phosphorites, evaporites, and uranium ores.

PubMed

Libby, L M; Libby, W F

1974-10-01

Oil deposits occur in deep sediments, and appear to be organic matter that has been transformed through the action of geothermal heat and pressure. Deep sediments, rich in biological remains, are created by ocean upwelling, caused in part by high geothermal heat flow through the sea bottom. Such regions correlate with enhanced seismic activity. We look for correlations of seismicity, high heat flux, petroleum, uranium, phosphates, and salts, deposited from abundant plant life. These may be useful in discovering more petroleum and coal. We estimate that the known world reserves of petroleum and coal are about 10(-4) of the total of buried biogenic carbon.

Geographical Coincidence of High Heat Flow, High Seismicity, and Upwelling, with Hydrocarbon Deposits, Phosphorites, Evaporites, and Uranium Ores

PubMed Central

Libby, L. M.; Libby, W. F.

1974-01-01

Oil deposits occur in deep sediments, and appear to be organic matter that has been transformed through the action of geothermal heat and pressure. Deep sediments, rich in biological remains, are created by ocean upwelling, caused in part by high geothermal heat flow through the sea bottom. Such regions correlate with enhanced seismic activity. We look for correlations of seismicity, high heat flux, petroleum, uranium, phosphates, and salts, deposited from abundant plant life. These may be useful in discovering more petroleum and coal. We estimate that the known world reserves of petroleum and coal are about 10-4 of the total of buried biogenic carbon. Images PMID:16592185

The East Slope No. 2 uranium prospect, Piute County, Utah

USGS Publications Warehouse

Wyant, Donald Gray

1954-01-01

The secondary uranium minerals autunite, metatorbernite, uranophane(?), and schroeckingerite occur in altered hornfels at the East Slope No. 9. uranium prospect. The deposit, in sec. 6, T. 9.7 S., R. 3 W., Piute County, Utah, is about 1 mile west of the Bullion Monarch mine which is in the central producing area of the Marysvale uranium district. Hornfels, formed by contact metamorphism of rocks of the Bullion Canyon volcanics borderhug the margin of a quartz monzonite stock, is in fault contact with the later Mount Belknap rhyolite. The hornfels was intensely altered by hydrothermal solutions in pre-Mount Belknap time. Hematite-alunite-quartz-kaolinite rock, the most completely altered hornfels, is surrounded by orange to white argillized hornfels containing beidellite-montmorillonite clay, and secondary uranium minerals. The secondary uranium minerals probably have been derived from pitchblende, the primary ore mineral in other deposits of the Marysvale area. The two uranium-rich zones, 4 feet ad 5 feet thick, have been traced on the surface for 60 feet and 110 feet, respectively. Channel samples from these zones contained as much as 0.047 percent uranium. The deposit is significant because of its position outside the central producing area and because of the association of uranium minerals with alunitic rock in hydrothermally altered hornfels of volcanic rocks of early Tertiary age.

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.30 Applicability; description of the...

The United States’ National Interests in Central Asia

DTIC Science & Technology

2000-03-23

Street Journal, 16 September 1997. 49 Ibid. 50 McHugh , Jane; Elfers, Steve. “Showtime for Sergeants.” Army Times, Vol 59, Issue 17 (23 November...petroleum, coal, manganese,chrome cant deposits of gold some petroleum, coal, sulfur, gold, uranium, ore, nickel , cobalt, and rare earth metals; uranium...Management Review, April 1999. McHugh , Jane; Elfers, Steve. “Showtime for Sergeants.” Army Times, Vol 59, Issue 17 (23 November 1998. Mikhailov

Increased Concentrations of Short-Lived Decay-Series Radionuclides in Groundwaters Underneath the Nopal I Uranium Deposit at Pena Blanca, Mexico

NASA Astrophysics Data System (ADS)

Luo, S.; Ku, T.; Todd, V.; Murrell, M. T.; Dinsmoor, J. C.

2007-05-01

The Nopal I uranium ore deposit at Pena Blanca, Mexico, located at > 200 meters above the groundwater table, provides an ideal natural analog for quantifying the effectiveness of geological barrier for isolation of radioactive waste nuclides from reaching the human environments through ground water transport. To fulfill such natural analog studies, three wells (PB1, PB2, and PB3 respectively) were drilled at the site from the land surface down to the saturated groundwater zone and ground waters were collected from each of these wells through large- volume sampling/in-situ Mn-filter filtration for analyses of short-lived uranium/thorium-series radionuclides. Our measurements from PB1 show that the groundwater standing in the hole has much lower 222Rn activity than the freshly pumped groundwater. From this change in 222Rn activity, we estimate the residence time of groundwater in PB1 to be about 20 days. Our measurements also show that the activities of short-lived radioisotopes of Th (234Th), Ra (228Ra, 224Ra, 223Ra), Rn (222Rn), Pb (210Pb), and Po (210Po) in PB1, PB2, and PB3 are all significantly higher than those from the other wells near the Nopal I site. These high activities provide evidence for the enrichment of long-lived U and Ra isotopes in the groundwater as well as in the associated adsorbed phases on the fractured aquifer rocks underneath the ore deposit. Such enrichment suggests a rapid dissolution of U and Ra isotopes from the uranium ore deposit in the vadose zone and the subsequent migration to the groundwater underneath. A reactive transport model can be established to characterize the in-situ transport of radionuclides at the site. The observed change of 222Rn activity at PB1 also suggests that the measured high radioactivityies in ground waters from the site isare not an artifact of drilling operations. However, further studies are needed to assess if or to what extent the radionuclide migration is affected by the previous mining activities at the site.

Safeguards on uranium ore concentrate? the impact of modern mining and milling process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francis, Stephen

2013-07-01

Increased purity in uranium ore concentrate not only raises the question as to whether Safeguards should be applied to the entirety of uranium conversion facilities, but also as to whether some degree of coverage should be moved back to uranium ore concentrate production at uranium mining and milling facilities. This paper looks at uranium ore concentrate production across the globe and explores the extent to which increased purity is evident and the underlying reasons. Potential issues this increase in purity raises for IAEA's strategy on the Starting Point of Safeguards are also discussed.

Fe-U-PGE-Au-Ag-Cu Deposits of the Udokan-Chiney Region (East Siberia, Russia)

NASA Astrophysics Data System (ADS)

Gongalskiy, B.; Krivolutskaya, N.; Murashov, K.; Nistratov, S.; Gryazev, S.

2012-04-01

Introduction. Cupriferous sandstones-shales and magmatic copper-nickel deposits mark out the western and southern boundaries of the Siberian Craton accordingly. Of special interest are the Paleoproterozoic deposits of the Udokan-Chiney mining district (Gongalskiy, Krivolutskaya, 2008). Copper reserves and resources of this region are estimated at more than 50 Mt. Half of them is concentrated at the unique Udokan Deposit and the second half is distributed among sedimentary (Unkur, Pravoingamakitskoye, Sakinskoye, Krasnoye, Burpala) and magmatic deposits of the Chiney (Rudnoye, Verkhnechineyskoye, Kontaktovoye), Luktur and Maylav massifs. Results. It was established that the ores are characterized by similarity in chemical composition (main, major and rare elements that are Ag, Au, PGE) and mineral assemblages with varying proportions. It is important to emphasize that Fe role in mineralization was previously ignored. Meanwhile the Udokan deposit contains 10 Mt of magnetite metacrystals so as chalcocite ores may contain up to 50% magnetite too. It has been recently found that the Chiney titanomagnetite ores comprise commercially significant uranium and rare-earth metal concentrations (Makaryev et al., 2011). Thus the Udokan-Chiney region comprises Cu, Fe, Ti, V, U, REE, Ag, Au, PGE. These deposits differ from similar objects, the Olympic Dam in particular, by a much smaller content of fluid-bearing minerals. Copper mineralization at the Udokan is represented by chalcocite-bornite ores. They occur as ore beds conformable with sedimentary structures or as cross-cutting veins. The central zones of the former are often brecciated. They are rimmed by fine magnetite, bornite, and chalcocite dissemination. Bornite-chalcopyrite and chalcopyrite-pyrite veins are known at the lower levels of the Udokan ore bed. Such ore compositions are predominant in other ore deposits in sedimentary rocks (Pravoingamakitskoye, Unkur) and have a hydrothermal origin. Silver grades are up to 370 g/t in grab samples (Gongalskiy et al., 2008a). The long-lived Udokan-Chiney ore-magmatic has small areal extent of explosive rocks and breccias (n*10 m) with massive sulfide veins (chalcopyrite, pyrrhotite) which are similar to Sudbury offset dikes. While the same vertical zones at the Rudnoye deposit have been confirmed over 0.5 km downward from the lower contact of the Chiney massif. Conclusions. Multielement and similar mineralogical composition ores of different deposits in the Udokan-Chiney area reflect long evolution of ore processes in very movable block of the crust. Observed combination of magmatic, sedimentary and partially hydrothermal deposits is a result of the telescoping of a wide range of metals into a limited area.

Radioactive deposits in California

USGS Publications Warehouse

Walker, George W.; Lovering, Tom G.

1954-01-01

Reconnaissance examination by Government geologists of many areas, mine properties, and prospects in California during the period between 1948 and 1953 has confirmed the presence of radioactive materials in place at more than 40 localities. Abnormal radioactivity at these localities is due to concentrations of primary and secondary uranium minerals, to radon gas, radium (?), and to thorium minerals. Of the known occurrences only three were thought to contain uranium oxide (uranitite or pitchblende), 4 contained uranium-bearing columbate, tantalate, or titanate minerals, 12 contained secondary uranium minerals, such as autunite, carnotite, and torbernite, one contained radon gas, 7 contained thorium minerals, and, at the remaining 16 localities, the source of the anomalous radiation was not positively determined. The occurrences in which uranium oxide has been tentatively identified include the Rathgeb mine (Calaveras County), the Yerih group of claims (San Bernardino County), and the Rainbow claim (Madera County). Occurrences of secondary uranium minerals are largely confined to the arid desert regions of south-eastern California including deposits in San Bernardino, Kern, Inyo, and Imperial Counties. Uranium-bearing columbate, tantalate, or titanate minerals have been reported from pegmatite and granitic rock in southeastern and eastern California. Thorium minerals have been found in vein deposits in eastern San Bernardino County and from pegmatites and granitic rocks in various parts of southeastern California; placer concentrations of thorium minerals are known from nearly all areas in the State that are underlain, in part, by plutonic crystalline rocks. The primary uranium minerals occur principally as minute accessory crystals in pegmatite or granitic rock, or with base-metal sulfide minerals in veins. Thorium minerals also occur as accessory crystals in pegmatite or granitic rock, in placer deposits derived from such rock, and, at Mountain Pass, in veins containing rare earths. Secondary uranium minerals have been found as fracture coatings and as disseminations in various types of wall rock, although they are largely confined to areas of Tertiary volcanic rocks. Probably the uranium in the uraniferous deposits in California is related genetically to felsic crystalline rocks and felsic volcanic rocks; the present distribution of the secondary uranium minerals has been controlled, in part, by circulating ground waters and probably, in part, by magmatic waters related to the Tertiary volcanic activity. The thorium minerals are genetically related to the intrusion of pegmatite and plutonic crystalline rocks. None of the known deposits of radioactive minerals in California contain marketable reserves of uranium or thorium ore under economic conditions existing in 1952. With a favorable local market small lots of uranium ore may be available in the following places: the Rosamund prospect, the Rafferty and Chilson properties, the Lucky Star claim, and the Yerih group. The commercial production of thorium minerals will be possible, in the near future, only if these minerals can be recovered cheaply as a byproduct either from the mining of rare earths minerals at Mountain Pass or as a byproduct of placer mining for gold.

Field Testing of Downgradient Uranium Mobility at an In-Situ Recovery Uranium Mine

NASA Astrophysics Data System (ADS)

Reimus, P. W.; Clay, J. T.; Rearick, M.; Perkins, G.; Brown, S. T.; Basu, A.; Chamberlain, K.

2015-12-01

In-situ recovery (ISR) mining of uranium involves the injection of O2 and CO2 (or NaHCO3) into saturated roll-front deposits to oxidize and solubilize the uranium, which is then removed by ion exchange at the surface and processed into U3O8. While ISR is economical and environmentally-friendly relative to conventional mining, one of the challenges of extracting uranium by this process is that it leaves behind a geochemically-altered aquifer that is exceedingly difficult to restore to pre-mining geochemical conditions, a regulatory objective. In this research, we evaluated the ability of the aquifer downgradient of an ISR mining area to attenuate the transport of uranium and other problem constituents that are mobilized by the mining process. Such an evaluation can help inform both regulators and the mining industry as to how much restoration of the mined ore zone is necessary to achieve regulatory compliance at various distances downgradient of the mining zone even if complete restoration of the ore zone proves to be difficult or impossible. Three single-well push-pull tests and one cross-well test were conducted in which water from an unrestored, previously-mined ore zone was injected into an unmined ore zone that served as a geochemical proxy for the downgradient aquifer. In all tests, non-reactive tracers were injected with the previously-mined ore zone water to allow the transport of uranium and other constituents to be compared to that of the nonreactive species. In the single-well tests, it was shown that the recovery of uranium relative to the nonreactive tracers ranged from 12-25%, suggesting significant attenuation capacity of the aquifer. In the cross-well test, selenate, molybdate and metavanadate were injected with the unrestored water to provide information on the transport of these potentially-problematic anionic constituents. In addition to the species-specific transport information, this test provided valuable constraints on redox conditions within the system, as redox couples involving these species collectively bracket the predicted transition redox potential for the U(VI)/U(IV) couple. Reduction should provide much longer-lasting immobilization of constituents than adsorption, especially given the inherent reducing characteristics of roll-front systems.

Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico.

PubMed

Goldstein, Steven J; Abdel-Fattah, Amr I; Murrell, Michael T; Dobson, Patrick F; Norman, Deborah E; Amato, Ronald S; Nunn, Andrew J

2010-03-01

Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ( approximately 10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that (230)Th/(238)U activity ratios range from 0.005 to 0.48 and (226)Ra/(238)U activity ratios range from 0.006 to 113. (239)Pu/(238)U mass ratios for the saturated zone are <2 x 10(-14), and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order (238)U approximately (226)Ra > (230)Th approximately (239)Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

Uranium mineralization and unconformities: how do they correlate? - A look beyond the classic unconformity-type deposit model?

NASA Astrophysics Data System (ADS)

Markwitz, Vanessa; Porwal, Alok; Campbell McCuaig, T.; Kreuzer, Oliver P.

2010-05-01

Uranium deposits are usually classified based on the characteristics of their host rocks and geological environments (Dahlkamp, 1993; OECD/NEA Red Book and IAEA, 2000; Cuney, 2009). The traditional unconformity-related deposit types are the most economical deposits in the world, with the highest grades amongst all uranium deposit types. In order to predict undiscovered uranium deposits, there is a need to understand the spatial association of uranium mineralization with structures and unconformities. Hydrothermal uranium deposits develop by uranium enriched fluids from source rocks, transported along permeable pathways to their depositional environment. Unconformities are not only separating competent from incompetent sequences, but provide the physico-chemical gradient in the depositional environment. They acted as important fluid flow pathways for uranium to migrate not only for surface-derived oxygenated fluids, but also for high oxidized metamorphic and magmatic fluids, dominated by their geological environment in which the unconformities occur. We have carried out comprehensive empirical spatial analyses of various types of uranium deposits in Australia, and first results indicate that there is a strong spatial correlation between unconformities and uranium deposits, not only for traditional unconformity-related deposits but also for other styles. As a start we analysed uranium deposits in Queensland and in particular Proterozoic metasomatic-related deposits in the Mount Isa Inlier and Late Carboniferous to Early Permian volcanic-hosted uranium occurrences in Georgetown and Charters Towers Regions show strong spatial associations with contemporary and older unconformities. The Georgetown Inlier in northern Queensland consists of a diverse range of rocks, including Proterozoic and early Palaeozoic metamorphic rocks and granites and late Palaeozoic volcanic rocks and related granites. Uranium-molybdenum (+/- fluorine) mineralization in the Georgetown inlier varies from strata- to structure-bound and occurs above regional unconformities. The Proterozoic basins in the Mount Isa Inlier rest unconformably on Palaeoproterozoic basement accompanied by volcanic and igneous rocks, which were deformed and metamorphosed in the Mesoproterozoic. Uranium occurrences in the Western Succession of Mount Isa are either hosted in clastic metasediments or mafic volcanics that belong to the Palaeoproterozoic Eastern Creek Volcanics. Uranium and vanadium mineralization occur in metasomatised and hematite-magnetite-carbonate alteration zones, bounded by major faults and regional unconformities. The results of this study highlight the importance of unconformities in uranium minerals systems as possible fluid pathways and/or surfaces of physico-chemical contrast that could have facilitated the precipitation of uranium, not only in classical unconformity style uranium deposits but in several other styles of uranium mineralization as well. References Cuney, M., 2009. The extreme diversity of uranium deposits. Mineralium Deposita, 44, 3-9. Dahlkamp, F. J., 1993. Uranium ore deposits. Springer, Berlin, p 460. OECD / NEA Red Book & IAEA, 2000. Uranium 1999: Resources, Production and Demand. OECD Nuclear Energy Agency and International Atomic Energy Agency, Paris.

Age and paragenesis of mineralisation at Coronation Hill uranium deposit, Northern Territory, Australia

NASA Astrophysics Data System (ADS)

Orth, Karin; Meffre, Sebastien; Davidson, Garry

2014-06-01

Coronation Hill is a U + Au + platinum group elements deposit in the South Alligator Valley (SAV) field in northern Australia, south of the better known unconformity-style U East Alligator Rivers (EAR) field. The SAV field differs from the EAR by having a more complex basin-basement architecture. A volcanically active fault trough (Jawoyn Sub-basin) developed on older basement and then was disrupted by renewed faulting, before being buried beneath regional McArthur Basin sandstones that are also the main hanging wall to the EAR deposits. Primary mineralisation at Coronation Hill formed at 1607 ± 26 Ma (rather than 600-900 Ma as previously thought), and so it is likely that the SAV was part of a single west McArthur Basin dilational event. Most ore is hosted in sub-vertical faults and breccias in the competent volcanic cover sequence. This favoured fluid mixing, acid buffering (forming illite) and oxidation of Fe2+ and reduced C-rich assemblages as important uranium depositional mechanisms. However, reduction of U in fractured older pyrite (Pb model age of 1833 ± 67 Ma) is an important trap in diorite. Some primary ore was remobilised at 675 ± 21 Ma to form coarse uraninite + Ni-Co pyrite networks containing radiogenic Pb. Coronation Hill is polymetallic, and in this respect resembles the `egress'-style U deposits in the Athabascan Basin (Canada). However, these are all cover-hosted. A hypothesis for further testing is that Coronation Hill is also egress-style, with ores formed by fluids rising through basement-hosted fault networks (U reduction by diorite pyrite and carbonaceous shale), and into veins and breccias in the overlying Jawoyn Sub-basin volcano-sedimentary succession.

Chemical data and statistical interpretations for rocks and ores from the Ranger uranium mine, Northern Territory, Australia

USGS Publications Warehouse

Nash, J. Thomas; Frishman, David

1983-01-01

Analytical results for 61 elements in 370 samples from the Ranger Mine area are reported. Most of the rocks come from drill core in the Ranger No. 1 and Ranger No. 3 deposits, but 20 samples are from unmineralized drill core more than 1 km from ore. Statistical tests show that the elements Mg, Fe, F, Be, Co, Li, Ni, Pb, Sc, Th, Ti, V, CI, As, Br, Au, Ce, Dy, La Sc, Eu, Tb, Yb, and Tb have positive association with uranium, and Si, Ca, Na, K, Sr, Ba, Ce, and Cs have negative association. For most lithologic subsets Mg, Fe, Li, Cr, Ni, Pb, V, Y, Sm, Sc, Eu, and Yb are significantly enriched in ore-bearing rocks, whereas Ca, Na, K, Sr, Ba, Mn, Ce, and Cs are significantly depleted. These results are consistent with petrographic observations on altered rocks. Lithogeochemistry can aid exploration, but for these rocks requires methods that are expensive and not amenable to routine use.

Thermodynamic properties of selected uranium compounds and aqueous species at 298.15 K and 1 bar and at higher temperatures; preliminary models for the origin of coffinite deposits

USGS Publications Warehouse

Hemingway, B.S.

1982-01-01

Thermodynamic values for 110 uranium-bearing phases and 28 aqueous uranium solution species (298.15 K and l bar) are tabulated based upon evaluated experimental data (largely from calorimetric experiments) and estimated values. Molar volume data are given for most of the solid phases. Thermodynamic values for 16 uranium-bearing phases are presented for higher temperatures in the form of and as a supplement to U.S. Geological Survey Bulletin 1452 (Robie et al., 1979). The internal consistency of the thermodynamic values reported herein is dependent upon the reliability of the experimental results for several uranium phases that have been used as secondary calorimetric reference phases. The data for the reference phases and for those phases evaluated with respect to the secondary reference phases are discussed. A preliminary model for coffinite formation has been proposed together with an estimate of the free energy of formation of coffinite. Free energy values are estimated for several other uranium-bearing silicate phases that have been reported as secondary uranium phases associated with uranium ore deposits and that could be expected to develop wherever uranium is leached by groundwaters.

U-Sries Disequilibra in Soils, Pena Blanca Natural Analog, Chihuahua, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

D. French; E. Anthony; P. Goodell

2006-03-16

The Nopal I uranium deposit located in the Sierra Pena Blanca, Mexico. The deposit was mined in the early 1980s, and ore was stockpiled close by. This stockpile area was cleared and is now referred to as the Prior High Grade Stockpile (PHGS). Some of the high-grade boulders from the site rolled downhill when it was cleared in the 1990s. For this study soil samples were collected from the alluvium surrounding and underlying one of these boulders. A bulk sample of the boulder was also collected. Because the Prior High Grade Stockpile had no ore prior to the 1980s amore » maximum residence time for the boulder is about 25 years, this also means that the soil was at background as well. The purpose of this study is to characterize the transport of uranium series radionuclides from ore to the soil. Transport is characterized by determining the activities of individual radionuclides and daughter to parent ratios. Isotopes of the uranium series decay chain detected include {sup 210}Pb, {sup 234}U, {sup 230}Th, {sup 226}Ra, {sup 214}Pb, and {sup 214}Bi. Peak areas for each isotope are determined using gamma-ray spectroscopy with a Canberra Ge (Li) detector and GENIE 2000 software. The boulder sample is close to secular equilibrium when compared to the standard BL-5 (Beaver Lodge Uraninite from Canada). Results for the soils, however, indicate that some daughter/parent pairs are in secular disequilibrium. These daughter/parent (D/P) ratios include {sup 230}Th/{sup 234}U, which is greater than unity, {sup 226}Ra/{sup 230}Th, which is also greater than unity, and {sup 210}Pb/{sup 214}Bi, which is less than unity. The gamma-ray spectrum for organic material lacks {sup 230}Th peaks, but contains {sup 234}U and {sup 226}Ra, indicating that plants preferentially incorporate {sup 226}Ra. Our results, combined with previous studies require multistage history of mobilization of the uranium series radionuclides. Earlier studies at the ore zone could limit the time span for mobilization only to a few thousand years. The contribution of this study is that the short residence time of the ore at the Prior High Grade Stockpile requires a time span for mobilization of 20-30 years.« less

Environmental Characteristics of Carbonatite and Alkaline Intrusion-related Rare Earth Element (REE) Deposits

NASA Astrophysics Data System (ADS)

Seal, R. R., II; Piatak, N. M.

2017-12-01

Carbonatites and alkaline intrusions are important sources of REEs. Environmental risks related to these deposit types have been assessed through literature review and evaluation of the geochemical properties of representative samples of mill tailings and their leachates. The main ore mineral in carbonatite deposits is bastnasite [(Ce,La)(CO3)F], which is found with dolomite and calcite ( 65 %), barite (20 - 25 %), plus a number of minor accessory minerals including sulfides such as galena and pyrite. Generally, alkaline intrusion-related REE deposits either occur in layered complexes or with dikes and veins cutting alkaline intrusions. Such intrusions have a more diverse group of REE ore minerals that include fluorcarbonates, oxides, silicates, and phosphates. Ore also can include minor calcite and iron (Fe), lead (Pb), and zinc (Zn) sulfides. The acid-generating potential of both deposit types is low because of a predominance of carbonate minerals in the carbonatite deposits, the presence of feldspars and minor calcite in alkaline intrusion-related deposits, and to only minor to trace occurrence of potentially acid-generating sulfide minerals. Both deposit types, however, are produced by igneous and hydrothermal processes that enrich high-field strength, incompatible elements, which typically are excluded from common rock-forming minerals. Elements such as yttrium (Y), niobium Nb), zirconium (Zr), hafnium (Hf), tungsten (W), titanium (Ti), tantalum (Ta), scandium (Sc), thorium (Th), and uranium (U) can be characteristic of these deposits and may be of environmental concern. Most of these elements, including the REEs, but with the exception of U, have low solubilities in water at the near-neutral pH values expected around these deposits. Mill tailings from carbonatite deposits can exceed residential soil and sediment criteria for Pb, and leachates from mill tailings can exceed drinking water guidelines for Pb. The greatest environmental challenges, however, are linked to the presence of Th and U, although mineral hosts for these elements are moderately unreactive in the environment. Both deposit types can have mill tailings that exceed residential soil criteria for U. Uranium can be recovered as a byproduct to mitigate its environmental effects, but Th remains a waste product that requires management.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-01-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-06-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Behavior of uranium under conditions of interaction of rocks and ores with subsurface water

NASA Astrophysics Data System (ADS)

Omel'Yanenko, B. I.; Petrov, V. A.; Poluektov, V. V.

2007-10-01

The behavior of uranium during interaction of subsurface water with crystalline rocks and uranium ores is considered in connection with the problem of safe underground insulation of spent nuclear fuel (SNF). Since subsurface water interacts with crystalline rocks formed at a high temperature, the mineral composition of these rocks and uranium species therein are thermodynamically unstable. Therefore, reactions directed toward the establishment of equilibrium proceed in the water-rock system. At great depths that are characterized by hindered water exchange, where subsurface water acquires near-neutral and reducing properties, the interaction is extremely sluggish and is expressed in the formation of micro- and nanoparticles of secondary minerals. Under such conditions, the slow diffusion redistribution of uranium with enrichment in absorbed forms relative to all other uranium species is realized as well. The products of secondary alteration of Fe- and Ti-bearing minerals serve as the main sorbents of uranium. The rate of alteration of minerals and conversion of uranium species into absorbed forms is slow, and the results of these processes are insignificant, so that the rocks and uranium species therein may be regarded as unaltered. Under reducing conditions, subsurface water is always saturated with uranium. Whether water interacts with rock or uranium ore, the equilibrium uranium concentration in water is only ≤10-8 mol/l. Uraninite ore under such conditions always remains stable irrespective of its age. The stability conditions of uranium ore are quite suitable for safe insulation of SNF, which consists of 95% uraninite (UO2) and is a confinement matrix for all other radionuclides. The disposal of SNF in massifs of crystalline rocks at depths below 500 m, where reducing conditions are predominant, is a reliable guarantee of high SNF stability. Under oxidizing conditions of the upper hydrodynamic zone, the rate of interaction of rocks with subsurface water increases by orders of magnitude and subsurface water is commonly undersaturated with uranium. Uranium absorbed by secondary minerals, particularly by iron hydroxides and leucoxene, is its single stable species under oxidizing conditions. The impact of oxygen-bearing water leads to destruction of uranium ore. This process is realized simultaneously at different hypsometric levels even if the permeability of the medium is variable in both the lateral and vertical directions. As a result, intervals containing uranyl minerals and relics of primary uranium ore are combined in ore-bearing zones with intervals of completely dissolved uranium minerals. A wide halo of elevated uranium contents caused by sorption is always retained at the location of uranium ore entirely destroyed by weathering. Uranium ore commonly finds itself in the aeration zone due to technogenic subsidence of the groundwater table caused by open-pit mining or pumping out of water from underground mines. The capillary and film waters that interact with rocks and ores in this zone are supplemented by free water filtering along fractures when rain falls or snow is thawing. The interaction of uranium ore with capillary water results in oxidation of uraninite, accompanied by loosening of the mineral surface, formation of microfractures, and an increase in solubility with enrichment of capillary water in uranium up to 10-4 mol/l. Secondary U(VI) minerals, first of all, uranyl hydroxides and silicates, replace uraninite, and uranium undergoes local diffusion redistribution with its sorption by secondary minerals of host rocks. The influx of free water facilitates the complete dissolution of primary and secondary uranium minerals, the removal of uranium at the sites of groundwater discharge, and its redeposition under reducing conditions at a greater depth. It is evident that the conditions of the upper hydrodynamic zone and the aeration zone are unfit for long-term insulation of SNF and high-level wastes because, after the failure of containers, the leakage of radionuclides into the environment becomes inevitable.

Geology of the Midnite uranium mine area, Washington: maps, description, and interpretation

USGS Publications Warehouse

Nash, J. Thomas

1977-01-01

Bedrock geology of about 12 km2 near the Midnite mine has been mapped at the surface, in mine exposures, and from drilling, at scales from 1:600 to 1:12,000 and is presented here at 1:12,000 to provide description of the setting of uranium deposits. Oldest rocks in the area are metapelitic and metacarbonate rocks of the Precambrian (Y) Togo Formation. The chief host for uranium deposits is graphitic and pyritic mica phyllite and muscovite schist. Ore also occurs in calc-silicate hornfels and marble at the western edge of a calcareous section about 1,150 m thick. Calcareous rocks of the Togo are probably older than the pelitic as they are interpreted to be near the axis of a broad anticline. The composition and structural position of the calcareous unit suggests correlation with less metamorphosed carbonate-bearing rocks of the Lower Wallace Formation, Belt Supergroup, about 200 km to the east. Basic sills intrusive into the Togo have been metamorphosed to amphibolite. Unmetamorphosed rocks in the mine area are Cretaceous(?) and Eocene igneous rocks. Porphyritic quartz monzonite of Cretaceous age, part of the Loon Lake batholith, is exposed over one third of the mine area. It underlies the roof pendant of Precambrian rocks in which the Midnite mine occurs at depths of generally less than 300 m. The pluton is a two-mica granite and exhibits pegmatitic and aplitic textural features indicative of water saturation and pressure quenching. Eocene intrusive and extrusive rocks in the area provide evidence that the Eocene surface was only a short distance above the present uranium deposits. Speculative hypotheses are presented for penesyngenetic, hydrothermal, and supergene modes of uranium emplacement. The Precambrian Stratigraphy, similar in age and pre-metamorphic lithology to that of rocks hosting large uranium deposits in Saskatchewan and Northern Territory, Australia, suggests the possibility of uranium accumulation along with diagenetic pyrite in carbonaceous muds in a marine shelf environment. This hypothesis is not favored by the author because there is no evidence for stratabound uranium such as high regional radioactivity in the Togo. A hydrothermal mode of uranium emplacement is supported by the close apparent ages of mineralization and plutonism, and by petrology of the pluton. I speculate that uranium may have become enriched in postmagmatic fluids at the top of the pluton, possibly by hydrothermal leaching of soluble uranium associated with magnetite, and diffused outward into metasedimentary wall rocks to create an aureole about 100 m thick containing about 100 ppm uranium. Chemistry of the hydrothermal process is not understood, but uranium does not appear to have been transported by an oxidizing fluid, and the fluid did not produce veining and alteration comparable to that of base-metal sulfide deposits. Uranium in the low-grade protore is believed to have been redistributed into permeable zones in the Tertiary to create ore grades. Geologic and isotopic ages of uranium mineralization, and the small volume of porphyritic quartz monzonite available for leaching, are not supportive of supergene emplacement of uranium.

Time-Series Radiocarbon Measurements Indicate Carbon Turnover Across Soil Fractions is Correlated With Productivity in a Long-Term Agricultural Experiment

NASA Astrophysics Data System (ADS)

Sanderman, J.; Baisden, W. T.; Creamer, C.; Farrell, M.; Fallon, S.

2016-12-01

Carbonatites and alkaline intrusions are important sources of REEs. Environmental risks related to these deposit types have been assessed through literature review and evaluation of the geochemical properties of representative samples of mill tailings and their leachates. The main ore mineral in carbonatite deposits is bastnasite [(Ce,La)(CO3)F], which is found with dolomite and calcite ( 65 %), barite (20 - 25 %), plus a number of minor accessory minerals including sulfides such as galena and pyrite. Generally, alkaline intrusion-related REE deposits either occur in layered complexes or with dikes and veins cutting alkaline intrusions. Such intrusions have a more diverse group of REE ore minerals that include fluorcarbonates, oxides, silicates, and phosphates. Ore also can include minor calcite and iron (Fe), lead (Pb), and zinc (Zn) sulfides. The acid-generating potential of both deposit types is low because of a predominance of carbonate minerals in the carbonatite deposits, the presence of feldspars and minor calcite in alkaline intrusion-related deposits, and to only minor to trace occurrence of potentially acid-generating sulfide minerals. Both deposit types, however, are produced by igneous and hydrothermal processes that enrich high-field strength, incompatible elements, which typically are excluded from common rock-forming minerals. Elements such as yttrium (Y), niobium Nb), zirconium (Zr), hafnium (Hf), tungsten (W), titanium (Ti), tantalum (Ta), scandium (Sc), thorium (Th), and uranium (U) can be characteristic of these deposits and may be of environmental concern. Most of these elements, including the REEs, but with the exception of U, have low solubilities in water at the near-neutral pH values expected around these deposits. Mill tailings from carbonatite deposits can exceed residential soil and sediment criteria for Pb, and leachates from mill tailings can exceed drinking water guidelines for Pb. The greatest environmental challenges, however, are linked to the presence of Th and U, although mineral hosts for these elements are moderately unreactive in the environment. Both deposit types can have mill tailings that exceed residential soil criteria for U. Uranium can be recovered as a byproduct to mitigate its environmental effects, but Th remains a waste product that requires management.

Preliminary report on radioactive conglomerates of Middle Precambrian age in the Sierra Madre and Medicine Bow Mountains of southeastern Wyoming

USGS Publications Warehouse

Houston, Robert Stroud; Graff, P.J.; Karlstrom, K.E.; Root, Forrest

1977-01-01

Middle Precambrian miogeosynclinal metasedimentary rocks o# the Sierra Madre and Medicine Bow Mountains of southeastern Wyoming contain radioactive quartz-pebble conglomerates of possible economic interest. These conglomerates do not contain ore-grade uranium in surface outcrops, but an earlier report on the geochemistry of the Arrastre Lake area of the Medicine Bow Mountains shows that ore-grade deposits may be present in the subsurface. This report describes the stratigraphy of the host metasedimentary rocks and the stratigraphic setting of the radioactive conglomerates in both the Sierra Madre and Medicine Bow Mountains, and compares these rock units with those of the Blind River-Elliot Lake uranium district in Canada. The location of radioactive .conglomerates is given so that further exploration may be undertaken by interested parties.

Preliminary study of radioactive limonite localities in Colorado, Utah, and Wyoming

USGS Publications Warehouse

Lovering, T.G.; Beroni, E.P.

1956-01-01

Nine radioactive limonite localities of different types were sampled during the spring and fall of 1953 in an effort to establish criteria for differentiating limonite outcrops associated with uranium or thorium deposits from limonite outcrops not associated with such deposits. The samples were analyzed for uranium and thorium by standard chemical methods, for equivalent uranium by the radiometric method, and for a number of common metals by semiquantitative geochemical methods. Correlation coefficients were then calculated for each of the metals with respect to equivalent uranium, and to uranium where present, for all of the samples from each locality. The correlation coefficients may indicate a significant association between uranium or thorium and certain metals. Occurrences of specific that are interpreted as significant very considerably for different uranium localities but are more consistent for the thorium localities. Samples taken from radioactive outcrops in the vicinity of uranium or thorium deposits can be quickly analyzed by geochemical methods for various elements. Correlation coefficients can then be determined for the various elements with respect to uranium or thorium; if any significant correlations are obtained, the elements showing such correlation may be indicators of uranium or thorium. Soil samples of covered areas in the vicinity of the radioactive outcrop may then be analyzed for the indicator elements and any resulting anomalies used as a guide for prospecting where the depth of overburden is too great to allow the use of radiation-detecting instruments. Correlation coefficients of the associated indicator elements, used in conjunction with petrographic evidence, may also be useful in interpreting the origin and paragenesis of radioactive deposits. Changes in color of limonite stains on the outcrop may also be a useful guide to ore in some areas.

Application of self-organizing maps to the study of U-Zr-Ti-Nb distribution in sandstone-hosted uranium ores

NASA Astrophysics Data System (ADS)

Klus, Jakub; Pořízka, Pavel; Prochazka, David; Mikysek, Petr; Novotný, Jan; Novotný, Karel; Slobodník, Marek; Kaiser, Jozef

2017-05-01

This paper presents a novel approach for processing the spectral information obtained from high-resolution elemental mapping performed by means of Laser-Induced Breakdown Spectroscopy. The proposed methodology is aimed at the description of possible elemental associations within a heterogeneous sample. High-resolution elemental mapping provides a large number of measurements. Moreover, typical laser-induced plasma spectrum consists of several thousands of spectral variables. Analysis of heterogeneous samples, where valuable information is hidden in a limited fraction of sample mass, requires special treatment. The sample under study is a sandstone-hosted uranium ore that shows irregular distribution of ore elements such as zirconium, titanium, uranium and niobium. Presented processing methodology shows the way to reduce the dimensionality of data and retain the spectral information by utilizing self-organizing maps (SOM). The spectral information from SOM is processed further to detect either simultaneous or isolated presence of elements. Conclusions suggested by SOM are in good agreement with geological studies of mineralization phases performed at the deposit. Even deeper investigation of the SOM results enables discrimination of interesting measurements and reveals new possibilities in the visualization of chemical mapping information. Suggested approach improves the description of elemental associations in mineral phases, which is crucial for the mining industry.

The physical hydrogeology of ore deposits

USGS Publications Warehouse

Ingebritsen, Steven E.; Appold, M.S.

2012-01-01

Hydrothermal ore deposits represent a convergence of fluid flow, thermal energy, and solute flux that is hydrogeologically unusual. From the hydrogeologic perspective, hydrothermal ore deposition represents a complex coupled-flow problem—sufficiently complex that physically rigorous description of the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes (THMC modeling) continues to challenge our computational ability. Though research into these coupled behaviors has found only a limited subset to be quantitatively tractable, it has yielded valuable insights into the workings of hydrothermal systems in a wide range of geologic environments including sedimentary, metamorphic, and magmatic. Examples of these insights include the quantification of likely driving mechanisms, rates and paths of fluid flow, ore-mineral precipitation mechanisms, longevity of hydrothermal systems, mechanisms by which hydrothermal fluids acquire their temperature and composition, and the controlling influence of permeability and other rock properties on hydrothermal fluid behavior. In this communication we review some of the fundamental theory needed to characterize the physical hydrogeology of hydrothermal systems and discuss how this theory has been applied in studies of Mississippi Valley-type, tabular uranium, porphyry, epithermal, and mid-ocean ridge ore-forming systems. A key limitation in the computational state-of-the-art is the inability to describe fluid flow and transport fully in the many ore systems that show evidence of repeated shear or tensional failure with associated dynamic variations in permeability. However, we discuss global-scale compilations that suggest some numerical constraints on both mean and dynamically enhanced crustal permeability. Principles of physical hydrogeology can be powerful tools for investigating hydrothermal ore formation and are becoming increasingly accessible with ongoing advances in modeling software.

Molecular marker and stable carbon isotope analyses of carbonaceous Ambassador uranium ores of Mulga Rock in Western Australia

NASA Astrophysics Data System (ADS)

Jaraula, C.; Schwark, L.; Moreau, X.; Grice, K.; Bagas, L.

2013-12-01

Mulga Rock is a multi-element deposit containing uranium hosted by Eocene peats and lignites deposited in inset valleys incised into Permian rocks of the Gunbarrel Basin and Precambrian rocks of the Yilgarn Craton and Albany-Fraser Orogen. Uranium readily adsorbs onto minerals or phytoclasts to form organo-uranyl complexes. This is important in pre-concentrating uranium in this relatively young ore deposit with rare uraninite [UO2] and coffinite [U(SiO4)1-x(OH)4x], more commonly amorphous and sub-micron uranium-bearing particulates. Organic geochemical and compound-specific stable carbon isotope analyses were conducted to identify possible associations of molecular markers with uranium accumulation and to recognize effect(s) of ionizing radiation on molecular markers. Samples were collected from the Ambassador deposit containing low (<200 ppm) to high (>2000 ppm) uranium concentrations. The bulk rock C/N ratios of 82 to 153, Rock-Eval pyrolysis yields of 316 to 577 mg hydrocarbon/g TOC (Hydrogen Index, HI) and 70 to 102 mg CO2/g TOC (Oxygen Index, OI) are consistent with a terrigenous and predominantly vascular plant OM source deposited in a complex shallow water system, ranging from lacustrine to deltaic, swampy wetland and even shallow lake settings as proposed by previous workers. Organic solvent extracts were separated into saturated hydrocarbon, aromatic hydrocarbon, ketone, and a combined free fatty acid and alcohol fraction. The molecular profiles appear to vary with uranium concentration. In samples with relatively low uranium concentrations, long-chain n-alkanes, alcohols and fatty acids derived from epicuticular plant waxes dominate. The n-alkane distributions (C27 to C31) reveal an odd/even preference (Carbon Preference Index, CPI=1.5) indicative of extant lipids. Average δ13C of -27 to -29 ‰ for long-chain n-alkanes is consistent with a predominant C3 plant source. Samples with relatively higher uranium concentrations contain mostly intermediate-length n-alkanes, ketones, alcohols, and fatty acids (C20 to C24) with no preferential distribution (CPI~1). Intermediate length n-alkanes have modest carbon isotope enrichment compared to long-chain n-alkanes. These shorter-chain hydrocarbons are interpreted to represent alteration products. The diversity and relative abundance of ketones in highly mineralised Mulga Rock peats and lignites are not consistent with aerobic and diagenetic degradation of terrigenous OM in oxic environments. Moreover, molecular changes cannot be associated with thermal breakdown due to the low maturity of the deposits. It is possible that the association of high uranium concentrations and potential radiolysis resulted in the oxidation of alcohol functional groups into aldehydes and ketones and breakdown of highly aliphatic macromolecules (i.e. spores, pollen, cuticles, and algal cysts). These phytoclasts are usually considered to be recalcitrant as they evolved to withstand chemical and physical degradation. Previous petrographic analyses show that spores, pollen and wood fragments are preferentially enriched in uranium. Their molecular compositions are feasible sources of short- to intermediate-length n-alkanes that dominate the mineralised peats and lignites.

Rare-earth element fractionation in uranium ore and its U(VI) alteration minerals

DOE PAGES

Balboni, Enrica; Spano, T; Cook, N; ...

2017-10-20

We developed a cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. This method was then applied to determine REE abundances in four uraninite (ideally UO 2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondarymore » uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca 2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K + and Pb 2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the latter may be attributed to the differing REE abundances between primary ore and associated alteration phases, and/or is related to varying fabrication processes adopted during production of UOC.« less

Rare-earth element fractionation in uranium ore and its U(VI) alteration minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Spano, T; Cook, N

We developed a cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. This method was then applied to determine REE abundances in four uraninite (ideally UO 2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondarymore » uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca 2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K + and Pb 2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the latter may be attributed to the differing REE abundances between primary ore and associated alteration phases, and/or is related to varying fabrication processes adopted during production of UOC.« less

Formation of Neogenic Ores on the Dump-Heaps of Old Uranium Mines and on the Mine-Head of Mines under Exploitation; FORMATION DE MINERAUX NEOGENES SUR LES HALDES D'ANCIENNES MINES D'URANIUM ET SUR LE CARREAU DES MINES EN EXPLOITATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chervet, J.

1960-01-01

The major degradations suffered by primary and secondary uranium ores under the weathering action of air and water are assessed. Pyritic ores were found to be the most vunerable. The interactions between pynite oxidation products and urantferous compounds often lead to the formation of neogentc ores. (C.J.G.)

Technological pretreatment of the synchysite non-oxidized ore

NASA Astrophysics Data System (ADS)

Munkhtsetseg, B.; Burmaa, G.

2013-06-01

Mongolia has rich deposits of rare, precious, and poly-metallic ores. Nowadays, it is important to research separation of rare earth elements oxides concentrates from the ores, analyze their unique physical chemical characteristics, and purified it. Our investigation on raw materials focuses on rare earth non-oxidized ores. Main mineral in this rock sample is Synchysite (LnCa(CO3)2F. We did technological and thermal pretreatment: direct sulphurization (H2SO4), sulphurization with subsequent roasting (800°C+H2SO4), sulphurization prior to roasting (H2SO4+650°C). Sulphurization method based on dissolution of rare earth mineral into sulfuric acid (93%) according to the reaction. The amount of rare earth element oxides is almost 10 times greater (29.16%) after direct sulphurization process, almost 8 times greater (21.14%) after sulphurization with subsequent roasting, and almost 20 times greater (44.62%) after sulphurization prior to roasting process. After those technological pretreatment raw material's micro elements Thorium and Uranium contents are reduced as follows: H2SO4>800°C+H2SO4>H2SO4+650°C. These results show that cerium group rare earth elements have very good solubility in water at +2°C temperature and decreasing micro elements content uranium and thorium good pretreatment condition is prior to roasting (H2SO4+650°C) of synchysite non-oxidized ore.

Wall-rock control of cortain pitchblende deposits in Golden Gate Canyon, Jefferson County, Colorado

USGS Publications Warehouse

Adams, John W.; Stugard, Frederick

1954-01-01

Carbonate veins cutting pre-Cambrian metamorphic rocks in Golden Gate Canyon contain pitchblende and base-metal sulfides. The veins occupy extensive faults of Laramide age but normally contain pitchblende only where the cut hornblende gneiss. At the Union Pacific prospect, which was studied in detail, pitchblende, hermatite, and some ankerite formed in advance of sulfides, except possibly for minor pyrite. Base-metal sulfides and the bulk of ankerite-calcite vein-filling were deposited after the pitchblende. Chemical analyses show a high ferrous iron content in the hornblende gneiss in contrast to low ferrous iron in the adjacent biotite gneiss. It is hypothesized that ferrous iron released by alteration of hornblende was partly oxidized to hematite by the ore-bearing solutions and, contemporaneously, uranium was reduced and deposited as pitchblende. In other veins, biotite or iron sulfides may have been similarly effective in precipitating pitchblende. Apparently both the ferrous ion and the sulfide ion can serve as reducing agents and control pitchblende deposition. It is suggested that conditions particularly favorable for uranium deposition are present where uranium-bearing solutions had access to rocks rich in ferrous iron or pre-existing sulfides.

Origin of the Mariano Lake uranium deposit, McKinley County, New Mexico

USGS Publications Warehouse

Fishman, Neil S.; Reynolds, Richard L.

1982-01-01

The Mariano Lake uranium deposit, hosted by the Brushy Basin Member of the Jurassic Morrison Formation, occurs in the trough of an east-west trending syncline at the western end of the Smith Lake-Mariano Lake group of uranium deposits near Crownpoint, New Mexico. The orebody, which contains abundant amorphous organic material, is situated on the reduced side of a regional reduction-oxidation (redox) interface. The presence of amorphous organic material suggests the orebody may represent a tabular (primary) deposit, whereas the close proximity of the orebody to the redox interface is suggestive that uranium was secondarily redistributed by oxidative processes from pre-existing tabular orebodies. Uranium contents correlate positively with both organic carbon and vanadium contents. Petrographic evidence and scanning electron microscope-energy dispersive analyses point to uranium residence in the epigentically introduced amorphous organic material, which coats detrital grains and fills voids. Uranium mineralization was preceded by the following diagenetic alterations: precipitation of pyrite (d34S values ranging from-11.0 to-38.2 per mil); precipitation of mixed-layer smectite-illite clays; partial dissolution of some of the detrital feldspar population; and precipitation of quartz and adularia overgrowths. Alterations associated with uranium mineralization include emplacement of amorphous organic material (possibly uranium bearing); destruction of detrital iron-titanium oxide grains; coprecipitation of chlorite and microcrystalline quartz, and precipitation of pyrite and marcasite (d34S values for these sulfides ranging from -29.4 to -41.6 per mil). After mineralization, calcite, dolomite, barite, and kaolinite precipitated, and authigenic iron disulfides were replaced by ferric oxides and hydroxides. Geochemical data (primarily the positive correlation of uranium content to both organic carbon and vanadium contents) and petrographic observations (epigentically introduced amorphous organic matter and uranium residence in this organic matter) indicate that the Mariano Lake orebody is a tabular-type uranium deposit. Oxidative processes have not noticeably redistributed and reconcentrated primary uranium in the immediate vicinity of the deposit nor have they greatly modified geochemical characteristics in the ore. Preservation of the Mariano Lake deposit may not only be related to its position along the synclinal trough, where oxidative destruction of the orebody has been inhibited by stagnation of oxidizing ground waters by the structure, but also due to the deflection of ground waters (resulting from low orebody porosity) around the orebody.

Study of the Dry Processing of Uranium Ores; ETUDE DES TRAITEMENTS DE MINERAIS D'URANIUM PAR VOIE SECHE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillet, H.

1959-02-01

A description is given of direct fluorination of preconcentrated uranium ores in order to obtain the hexafluoride. After normal sulfuric acid treatment of the ore to eliminate silica, the uranium is precipitated by lime to obtain either impure calcium uranate of medium grade, or containing around 10% of uranium. This concentrate is dried in an inert atmosphere and then treated with a current of elementary fluorine. The uranium hexafluoride formed is condensed at the outlet of the reaction vessel and may be used either for reduction to tetrafluoride and the subsequent manufacture of uranium metal or as the initial productmore » in a diffusion plant. (auth)« less

Re-evaluation of the petrogenesis of the Proterozoic Jabiluka unconformity-related uranium deposit, Northern Territory, Australia

NASA Astrophysics Data System (ADS)

Polito, Paul A.; Kurt Kyser, T.; Thomas, David; Marlatt, Jim; Drever, Garth

2005-11-01

The world class Jabiluka unconformity-related uranium deposit in the Alligator Rivers Uranium Field, Australia, contains >163,000 tons of contained U3O8. Mineralization is hosted by shallow-to-steeply dipping basement rocks comprising graphitic units of chlorite-biotite-muscovite schist. These rocks are overlain by flat-lying coarse-grained sandstones belonging to the Kombolgie Subgroup. The deposit was discovered in 1971, but has never been mined. The construction of an 1,150 m decline into the upper eastern sector of the Jabiluka II deposit combined with closely spaced underground drilling in 1998 and 1999 allowed mapping and sampling from underground for the first time. Structural mapping, drill core logging and petrographic studies on polished thin sections established a detailed paragenesis that provided the framework for subsequent electron microprobe and X-ray diffraction, fluid inclusion, and O-H, U-Pb and 40Ar/39Ar isotope analysis. Uranium mineralization is structurally controlled within semi-brittle shears that are sub-conformable to the basement stratigraphy, and breccias that are developed within the hinge zone of fault-related folds adjacent to the shears. Uraninite is intimately associated with chlorite, sericite, hematite ± quartz. Electron microprobe and X-ray diffraction analysis of syn-ore illite and chlorite indicates a mineralization temperature of 200°C. Pre- and syn-ore minerals extracted from the Kombolgie Subgroup overlying the deposit and syn-ore alteration minerals in the Cahill Formation have δ18Ofluid and δ D fluid values of 4.0±3.7 and -27±17‰, respectively. These values are indistinguishable from illite separates extracted from diagenetic aquifers in the Kombolgie Subgroup up to 70 km to the south and east of the deposit and believed to be the source of the uraniferous fluid. New fluid inclusion microthermometry data reveal that the mineralising brine was saline, but not saturated. U-Pb and 207Pb/206Pb ratios of uraninite by laser-ablation ICP-MS suggest that massive uraninite first precipitated at ca. 1,680 Ma, which is coincident with the timing of brine migration out from the Kombolgie Subgroup as indicated by 40Ar/39Ar ages of 1,683±11 Ma from sandstone-hosted illite. Unmineralized breccias cemeted by chlorite, quartz and sericite cross-cut the mineralized breccias and are in turn cut by straight-sided, high-angle veins of drusy quartz, sulphide and dolomite. U-Pb and 207Pb/206Pb ratios combined with fluid inclusion and stable isotope data indicate that these post-ore minerals formed when mixing between two fluids occurred sometime between ca. 1,450 and 550 Ma. Distinct 207Pb/206Pb age populations occur at ca. 1,302±37, 1,191±27 and 802±57 Ma, which respectively correlate with the intrusion of the Maningkorrirr/Mudginberri phonolitic dykes and the Derim Derim Dolerite between 1,370 and 1,316 Ma, the amalgamation of Australia and Laurentia during the Grenville Orogen at ca. 1,140 Ma, and the break-up of Rodinia between 1,000 and 750 Ma.

Statistical analysis of soil geochemical data to identify pathfinders associated with mineral deposits: An example from the Coles Hill uranium deposit, Virginia, USA

USGS Publications Warehouse

Levitan, Denise M.; Zipper, Carl E.; Donovan, Patricia; Schreiber, Madeline E.; Seal, Robert; Engle, Mark A.; Chermak, John A.; Bodnar, Robert J.; Johnson, Daniel K.; Aylor, Joseph G.

2015-01-01

Soil geochemical anomalies can be used to identify pathfinders in exploration for ore deposits. In this study, compositional data analysis is used with multivariate statistical methods to analyse soil geochemical data collected from the Coles Hill uranium deposit, Virginia, USA, to identify pathfinders associated with this deposit. Elemental compositions and relationships were compared between the collected Coles Hill soil and reference soil samples extracted from a regional subset of a national-scale geochemical survey. Results show that pathfinders for the Coles Hill deposit include light rare earth elements (La and Ce), which, when normalised by their Al content, are correlated with U/Al, and elevated Th/Al values, which are not correlated with U/Al, supporting decoupling of U from Th during soil generation. These results can be used in genetic and weathering models of the Coles Hill deposit, and can also be applied to future prospecting for similar U deposits in the eastern United States, and in regions with similar geological/climatic conditions.

PROCESS OF RECOVERING URANIUM FROM ITS ORES

DOEpatents

Galvanek, P. Jr.

1959-02-24

A process is presented for recovering uranium from its ores. The crushed ore is mixed with 5 to 10% of sulfuric acid and added water to about 5 to 30% of the weight of the ore. This pugged material is cured for 2 to 3 hours at 100 to 110 deg C and then cooled. The cooled mass is nitrate-conditioned by mixing with a solution equivalent to 35 pounds of ammunium nitrate and 300 pounds of water per ton of ore. The resulting pulp containing 70% or more solids is treated by upflow percolation with a 5% solution of tributyl phosphate in kerosene at a rate equivalent to a residence time of about one hour to extract the solubilized uranium. The uranium is recovered from the pregnant organic liquid by counter-current washing with water. The organic extractant may be recycled. The uranium is removed from the water solution by treating with ammonia to precipitate ammonium diuranate. The filtrate from the last step may be recycled for the nitrate-conditioning treatment.

The comparative analysis of payments for negative environmental impact in Russia and Kazakhstan

NASA Astrophysics Data System (ADS)

Tsibulnikova, M. R.; Ospanov, A. T.; Salata, D. V.; Strelnikova, A. B.

2015-11-01

The article represents the calculation of the payment for negative environmental impact caused by the development of the uranium ores deposits in the Republic of Kazakhstan. To compare the deposits in Kazakhstan and the Russian Federation, the event is simulated as if the object were located in the territory of the Russian Federation. The comparison of the results serves as an evidence to substantiate the experts’ claim that the financial mechanism of land management in Russia should be reformed.

CATALYZED OXIDATION OF URANIUM IN CARBONATE SOLUTIONS

DOEpatents

Clifford, W.E.

1962-05-29

A process is given wherein carbonate solutions are employed to leach uranium from ores and the like containing lower valent uranium species by utilizing catalytic amounts of copper in the presence of ammonia therein and simultaneously supplying an oxidizing agent thereto. The catalysis accelerates rate of dissolution and increases recovery of uranium from the ore. (AEC)

PHYSICAL BENEFICATION OF LOW-GRADE URANIUM ORES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, J.N.

1958-07-30

Investigations are presented of methods for the physi cal beneficiation of low-grade and other uranium ores. The investlgations which have been in progress since September 1952 cover work done on a variety of natural ores, as well as a certain amount of basic research on mixtures of synthetic or high-grade natural uranium minerais with various gangues. Methods of beneficlation investigated include flotation, wet and dry attroftioning, magnetic separation. electresiatie separation, and misceilaneous minor methods. A rapid, routine method oicolorimeiric determlnation of uranium was also developed in order to facilitaie analyzing of low-grade materials for uranium. This proeedure is presenied inmore » condensed form. (auth)« less

SOLVENT EXTRACTION PROCESS FOR URANIUM RECOVERY

DOEpatents

Clark, H.M.; Duffey, D.

1958-06-17

A process is described for extracting uranium from uranium ore, wherein the uranium is substantially free from molybdenum contamination. In a solvent extraction process for recovering uranium, uranium and molybdenum ions are extracted from the ore with ether under high acidity conditions. The ether phase is then stripped with water at a lower controiled acidity, resaturated with salting materials such as sodium nitrate, and reextracted with the separation of the molybdenum from the uranium without interference from other metals that have been previously extracted.

Depositional environments of the uranium-bearing Cutler Formations, Lisbon Valley, Utah

USGS Publications Warehouse

Campbell, John A.; Steele-Mallory, Brenda A.

1979-01-01

The Cutler Formation in Lisbon Valley, San Juan County, Utah, is composed predominantly of fluvial arkosic sandstones, siltstones, shales, and mudstones that were deposited by meandering streams that flowed across a flood plain and tidal flat close to sea level. Two types of channel deposits are recognized from their sedimentary structures: meandering and distributary. The flood plain was occasionally transgressed by a shallow sea from the west, resulting in the deposition of several thin limestones and marine sandstones. The marine sandstones were deposited as longshore bars. Wind transported sand along the shoreline of the shallow sea, forming a coastal dune field. Marine sandstones and eolian sandstones are more common in the upper Cutler in the southern part of the area, whereas in the central and northern part of the area the formation is predominantly fluvial. Crossbed orientation indicates that Cutler streams flowed S. 67? W. on the the average, whereas marine currents moved sediment S. 36? E. and N. 24? W., and wind transported sand S. 800 E. The uranium in the Cutler is found in the central and northern part of the area, in the upper part of the formation, in small fluvial sandstone bodies that were deposited predominantly in a distributary environment. No uranium is known in the marine or eolian sandstones. Petrographically, the uranium-bearing sandstones are identical to other Cutler fluvial sandstones except that they contain less calcite and more clay and are slightly coarser grained. Ore formation has modified the host sandstones very little.

ASTER, ALI and Hyperion sensors data for lithological mapping and ore minerals exploration.

PubMed

Beiranvand Pour, Amin; Hashim, Mazlan

2014-01-01

This paper provides a review of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Land Imager (ALI), and Hyperion data and applications of the data as a tool for ore minerals exploration, lithological and structural mapping. Spectral information extraction from ASTER, ALI, and Hyperion data has great ability to assist geologists in all disciplines to map the distribution and detect the rock units exposed at the earth's surface. The near coincidence of Earth Observing System (EOS)/Terra and Earth Observing One (EO-1) platforms allows acquiring ASTER, ALI, and Hyperion imagery of the same ground areas, resulting accurate information for geological mapping applications especially in the reconnaissance stages of hydrothermal copper and gold exploration, chromite, magnetite, massive sulfide and uranium ore deposits, mineral components of soils and structural interpretation at both regional and district scales. Shortwave length infrared and thermal infrared bands of ASTER have sufficient spectral resolution to map fundamental absorptions of hydroxyl mineral groups and silica and carbonate minerals for regional mapping purposes. Ferric-iron bearing minerals can be discriminated using six unique wavelength bands of ALI spanning the visible and near infrared. Hyperion visible and near infrared bands (0.4 to 1.0 μm) and shortwave infrared bands (0.9 to 2.5 μm) allowed to produce image maps of iron oxide minerals, hydroxyl-bearing minerals, sulfates and carbonates in association with hydrothermal alteration assemblages, respectively. The techniques and achievements reviewed in the present paper can further introduce the efficacy of ASTER, ALI, and Hyperion data for future mineral and lithological mapping and exploration of the porphyry copper, epithermal gold, chromite, magnetite, massive sulfide and uranium ore deposits especially in arid and semi-arid territory.

PROCESS OF EXTRACTING URANIUM AND RADIUM FROM ORES

DOEpatents

Sawyer, C.W.; Handley, R.W.

1959-07-14

A process is presented for extracting uranium and radium values from a uranium ore which comprises leaching the ore with a ferric chloride solution at an elevated temperature of above 50 deg C and at a pH less than 4; separating the ore residue from the leaching solution by filtration; precipitating the excess ferric iron present at a pH of less than 5 by adding CaCO/sub 3/ to the filtrate; separating the precipitate by filtration; precipitating the uranium present in the filtrate at a Ph less than 6 by adding BaCO/sub 3/ to the filtrate; separating the precipitate by filtration; and precipitating the radium present in the filtrate by adding H/sub 2/SO/sub 4/ to the filtrate.

Did the Kiruna iron ores form as a result of a metasomatic or igneous process? New U-Pb and Nd data for the iron oxide apatite ores and their host rocks in the Norrbotten region of northern Sweden

NASA Astrophysics Data System (ADS)

Westhues, A.; Hanchar, J. M.; Whitehouse, M. J.; Fisher, C. M.

2012-12-01

A number of iron deposits near Kiruna in the Norrbotten region of northern Sweden are of the iron oxide apatite (IOA) type of deposits; also referred to as Kiruna-type deposits. They are commonly considered a subgroup or end-member of iron oxide copper gold (IOCG) deposits, containing no economic grades of copper or gold. Both IOCG and IOA deposits are characterized by abundant low-Ti Fe oxides, an enrichment in REE, and intense sodium and potassium wall-rock alteration adjacent to the ores. Deposits of these types are of a great economic importance, not only for iron, but also for other elements such as rare earth elements (REE) or uranium. Kiruna, the type locality of the IOA type of mineral deposits, is the focus of this study. Despite a century-long mining history and 2500 Mt of iron ore produced in the region to date (with grades of 30 to 70 wt.% Fe), the genesis of these deposits is poorly understood: theories of a magmatic vs. a hydrothermal or metasomatic origin have been debated, and the timing of mineralization of the ores in the Norbotten region has never been directly dated. The results anticipated from this study will provide a better understanding of the nature of the IOA type of mineral deposits and their relation to IOCG deposits such as Olympic Dam in Australia. An array of geochemical methods is used in order to gain insights on the emplacement history of the host rocks, their subsequent alteration, and the ore genesis of these deposits. This includes in situ U/Pb geochronology of zircon, monazite, and titanite to constrain the timing between host rock emplacement, alteration and mineralization. Isotopic data from whole rocks and in situ at mineral scale will provide constraints on the involvement of hydrothermal fluids and their possible sources, as well as on the sources of Fe, U, and the REE. Newly obtained Sm-Nd isotopic data points to distinct source differences between host rocks, ore and alteration related samples. Preliminary in situ U-Pb dating of zircon from both host rock and ore samples confirms a previously documented event around 1880 - 1900 Ma in the Norrbotten region. However, U-Pb in monazite from an ore sample suggests a further event at ca. 1650 Ma, a period of known activity in Fennoscandia. Further investigation and more U-Pb data are needed to confirm those dates and how the iron mineralization is related to those two events. The combination of U-Th-Pb ages, tracer isotopes and trace element abundances at mineral scale (e.g., Lu-Hf in zircon, and Sm-Nd in monazite, apatite, titanite), along with the O isotopic composition of zircon, will be used to decipher whether the Kiruna iron ore deposits are of metasomatic or igneous origin. Overall, the study also intends to develop a predictive model for exploration of similar iron oxide apatite deposits worldwide.

Three-dimensional inversion of magnetotelluric data for mineral exploration: An example from the McArthur River uranium deposit, Saskatchewan, Canada

NASA Astrophysics Data System (ADS)

Farquharson, Colin G.; Craven, James A.

2009-08-01

Shallow exploration targets are becoming scarce, meaning interest is turning towards deeper targets. The magnetotelluric method has the necessary depth capability, unlike many of the controlled-source electromagnetic prospecting techniques traditionally used. The geological setting of ore deposits is usually complex, requiring three-dimensional Earth models for their representation. An example of the applicability of three-dimensional inversion of magnetotelluric data to mineral exploration is presented here. Inversions of an audio-magnetotelluric data-set from the McArthur River uranium mine in the Athabasca Basin were carried out. A sub-set comprising data from eleven frequencies distributed over almost three decades was inverted. The form of the data used in the inversion was impedance. All four elements of the tensor were included. No decompositions of the data were done, nor rotation to a preferred strike direction, nor correction for static shifts. The inversions were successful: the observations were adequately reproduced and the main features in the conductivity model corresponded to known geological features. These included the graphitic basement fault along which the McArthur River uranium deposit is located.

Paleontological analysis of a lacustrine carbonaceous uranium deposit at the Anderson mine, Date Creek basin, west-central Arizona (U.S.A.)

USGS Publications Warehouse

Otton, J.K.; Bradbury, J.P.; Forester, R.M.; Hanley, J.H.

1990-01-01

The Tertiary sedimentary sequence of the Date Creek basin area of Arizona is composed principally of intertonguing alluvial-fan and lacustrine deposits. The lacustrine rocks contain large intermediate- to, locally, high-grade uranium deposits that form one of the largest uranium resources in the United States (an estimated 670,000 tons of U3O8 at an average grade of 0.023% is indicated by drilling to date). At the Anderson mine, about 50,000 tons of U3O8 occurs in lacustrine carbonaceous siltstones and mudstones (using a cutoff grade of 0.01%). The Anderson mine constitutes a new class of ore deposit, a lacustrine carbonaceous uranium deposit. Floral and faunal remains at the Anderson mine played a critical role in creating and documenting conditions necessary for uranium mineralization. Organic-rich, uraniferous rocks at the Anderson mine contain plant remains and ostracodes having remarkably detailed preservation of internal features because of infilling by opaline silica. This preservation suggests that the alkaline lake waters in the mine area contained high concentrations of dissolved silica and that silicification occurred rapidly, before compaction or cementation of the enclosing sediment. Uranium coprecipitated with the silica. Thinly laminated, dark-colored, siliceous beds contain centric diatoms preserved with carbonaceous material suggesting that lake waters at the mine were locally deep and anoxic. These alkaline, silica-charged waters and a stagnant, anoxic environment in parts of the lake were necessary conditions for the precipitation of large amounts of uranium in the lake-bottom sediments. Sediments at the Anderson mine contain plant remains and pollen that were derived from diverse vegetative zones suggesting about 1500 m of relief in the area at the time of deposition. The pollen suggests that the valley floor was semiarid and subtropical, whereas nearby mountains supported temperate deciduous forests. ?? 1990.

A Metal Stable Isotope Approach to Understanding Uranium Mobility Across Roll Front Redox Boundaries

NASA Astrophysics Data System (ADS)

Brown, S. T.; Basu, A.; Christensen, J. N.; DePaolo, D. J.; Heikoop, J. M.; Reimus, P. W.; Maher, K.; Weaver, K. L.

2015-12-01

Sedimentary roll-front uranium (U) ore deposits are the principal source of U for nuclear fuel in the USA and an important part of the current all-of-the-above energy strategy. Mining of roll-front U ore in the USA is primarily by in situ alkaline oxidative dissolution of U minerals. There are significant environmental benefits to in situ mining including no mine tailings or radioactive dust, however, the long-term immobilization of U in the aquifer after the completion of mining remains uncertain. We have utilized the metal stable isotopes U, Se and Mo in groundwater from roll-front mines in Texas and Wyoming to quantify the aquifer redox conditions and predict the onset of U reduction after post mining aquifer restoration. Supporting information from the geochemistry of groundwater and aquifer sediments are used to understand the transport of U prior to and after in situ mining. Groundwater was collected across 4 mining units at the Rosita mine in the Texas coastal plain and 2 mining units at the Smith Ranch mine in the Powder River Basin, Wyoming. In general, the sampled waters are moderately reducing and ore zone wells contain the highest aqueous U concentrations. The lowest U concentrations occur in monitoring wells downgradient of the ore zone. 238U/235U is lowest in downgradient wells and is correlated with aqueous U concentrations. Rayleigh distillation models of the 238U/235U are consistent with U isotope fractionation factors of 1.0004-1.001, similar to lab-based studies. Based on these results we conclude that redox reactions continue to affect U distribution in the ore zone and downgradient regions. We also measured aqueous selenium isotope (δ82Se) and molybdenum isotope (δ98Mo) compositions in the Rosita groundwater. Se(VI) primarily occurs in the upgradient wells and is absent in most ore zone and downgradient wells. Rayleigh distillation models suggest reduction of Se(VI) along the groundwater flow path and when superimposed on the U isotope data Se reduction is favored over U reduction. The δ98Mo of Rosita groundwater is significantly elevated compared to the U ore and is negatively correlated with the groundwater Eh, which suggests localized strong reducing conditions capable of Mo reduction. Ongoing work will determine the Mo isotope systematics of U ores and groundwater from roll-front deposits.

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2012 CFR

2012-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2014 CFR

2014-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2011 CFR

2011-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2013 CFR

2013-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

Using Pb isotopes in surface media to distinguish anthropogenic sources from undercover uranium sources

NASA Astrophysics Data System (ADS)

Kyser, Kurt; Lahusen, Larry; Drever, Garth; Dunn, Colin; Leduc, Evelyne; Chipley, Don

2015-09-01

The response in elemental concentrations and Pb isotopes in various surface media from the Cigar West unconformity-type uranium deposit located at a depth of 450 m were measured to ascertain if element migration from the deposit can be detected at the surface. The media included clay-size fractions separated from the A2, B and C soil horizons, and tree cores and twigs from black spruce (Picea mariana) and jack pine (Pinus banksiana) trees. Lead isotopes were used to trace any effect on the surface media from the deposit at depth because the 207Pb/206Pb ratios in the ore are < 0.1, whereas the background values in the basin are > 0.7 and modern anthropogenic Pb from aerosols are near 0.9. The tree cores record their lowest and therefore most radiogenic 207Pb/206Pb ratios of < 0.7 near the surface projection of the deposit and associated structures, particularly in tree rings that predate any exploration and drilling activity in the area. The median 207Pb/206Pb ratios increase in the order C, B soil horizon clays, tree cores, A2 soil clays and twigs because of the increasing contribution of common Pb with high ratios from anthropogenic sources that affect the shallowest media the most. Although this anthropogenic Pb as well as that from the background dominates the composition of all media at the surface and the contribution from the deposit at depth is diminished toward the surface, ore-related Pb is still present as a few percent of the composition of pathfinder elements and Pb isotopes.

Spatial variability and geochemistry of rare earth elements in soils from the largest uranium-phosphate deposit of Brazil.

PubMed

Cunha, Cleyton Saialy Medeiros; da Silva, Ygor Jacques Agra Bezerra; Escobar, Maria Eugenia Ortiz; do Nascimento, Clístenes Williams Araújo

2018-02-22

The Itataia uranium-phosphate deposit is the largest uranium reserve in Brazil. Rare earth elements (REEs) are commonly associated with phosphate deposits; however, there are no studies on the concentrations of REEs in soils of the Itataia deposit region. Thus, the objective of the research was to evaluate the concentration and spatial variability of REEs in topsoils of Itataia phosphate deposit region. In addition, the influence of soil properties on the geochemistry of REEs was investigated. Results showed that relatively high mean concentrations (mg kg -1 ) of heavy REEs (Gd 6.01; Tb 1.25; Ho 1.15; Er 4.05; Tm 0.64; Yb 4.61; Lu 0.65) were found in surface soils samples. Soil properties showed weak influence on the geochemical behavior of REEs in soils, except for the clay content. On the other hand, parent material characteristics, such as P and U, had strong influence on REEs concentrations. Spatial distribution patterns of REEs in soils are clearly associated with P and U contents. Therefore, geochemical surveys aiming at the delineation of ore-bearing zones in the region can benefit from our data. The results of this work reinforce the perspective for co-mining of P, U and REEs in this important P-U reserve.

Olympic Dam copper-uranium-gold deposit, South Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lalor, J.H.

1986-07-01

The Olympic Dam copper-uranium-gold deposit was discovered in July 1975. It is located 650 km north-northwest of Adelaide on Roxby Downs Station in South Australia. The first diamond drill hole, RD1, intersected 38 m of 1.05% copper. A further eight holes were drilled with only marginal encouragement to November 1976, when RD10 cored 170 m of 2.12% copper and 0.06% of uranium oxide, thus confirming an economic discovery. The discovery of Olympic Dam is an excellent example applying broad-scale, scientifically based conceptual studies to area selection. Exploration management supported its exploration scientists in testing their ideas with stratigraphic drilling. Geologicmore » modeling, supported by geophysical interpretations and tectonic studies, was used to site the first hole. The discovery also illustrates the persistence required in mineral exploration. The deposit appears to be a new type of stratabound sediment-hosted ore. It has an areal extent exceeding 20 km/sup 2/ with vertical thicknesses of mineralization up to 350 m. It is estimated to contain more than 2000 million MT of mineralized material with an average grade of 1.6% copper, 0.06% uranium oxide, and 0.6 g/MT gold. The deposit occurs in middle Proterozoic basement beneath 350 m of unmineralized, flat upper Proterozoic sediments. The sediments comprising the local basement sequence are predominantly sedimentary breccias controlled by a northwest-trending graben.« less

Uranium occurrences in the Golden Gate Canyon and Ralston Creek areas, Jefferson County, Colorado

USGS Publications Warehouse

Adams, John Wagstaff; Gude, A.J.; Beroni, E.P.

1953-01-01

Pitchblende, associated with base-metal sulfides, has been found at nine localities in the northern part of Jefferson County, Colo., in shear zones that cut pre-Cambrian metamorphic and igneous rocks, chiefly hornblende gneiss, biotite schist, and granite pegmatite. The known deposits are in the vicinity of Halston Creek and Golden Gate Canyon, in the foothills of the Colorado Front Range and about 15 miles east of the pitchblende-producing area of the Central City district. Two of the pitchblende occurrences were found by a local prospector in 1949; the seven other deposits were found by Geological Survey. personnel in 1951-52. The pitchblende deposits, with one exception, are in major shear zones that contain veinlike bodies of carbonate-rich breccia that ranges from 1 to 5 feet in thickness. The breccias probably are related to the Laramide faults, or 'breccia reefs' of similar trend, mapped by Loverinq and Goddard (1950). The breccias are composed of fragments of bleached and iron-stained wall rock, usually hornblende gneiss, that have been cut by veins and cemented by carbonate minerals, quartz, and orthoclase(?). Pitchblende and associated ore minerals, chiefly copper sulfides, occur in and along the margins of the breccias and apparently were introduced at a late stage of the carbonate deposition. At one deposit, the Buckman, the pitchblende is in narrow shear zones not closely related to any large breccia bodies. Secondary uranium minerals are subordinate except at the Schwartzwalder mine, where torbernite and metatorbernite are common. Some alteration of pitchblende to non-opaque materials, believed to be hydrated oxides, has been noted in ore from two of the deposits.

Modeling and experimental examination of water level effects on radon exhalation from fragmented uranium ore.

PubMed

Ye, Yong-Jun; Dai, Xin-Tao; Ding, De-Xin; Zhao, Ya-Li

2016-12-01

In this study, a one-dimensional steady-state mathematical model of radon transport in fragmented uranium ore was established according to Fick's law and radon transfer theory in an air-water interface. The model was utilized to obtain an analytical solution for radon concentration in the air-water, two-phase system under steady state conditions, as well as a corresponding radon exhalation rate calculation formula. We also designed a one-dimensional experimental apparatus for simulating radon diffusion migration in the uranium ore with various water levels to verify the mathematical model. The predicted results were in close agreement with the measured results, suggesting that the proposed model can be readily used to determine radon concentrations and exhalation rates in fragmented uranium ore with varying water levels. Copyright © 2016. Published by Elsevier Ltd.

URANIUM RECOVERY PROCESS

DOEpatents

Yeager, J.H.

1958-08-12

In the prior art processing of uranium ores, the ore is flrst digested with nitric acid and filtered, and the uranium values are then extracted tom the filtrate by contacting with an organic solvent. The insoluble residue has been processed separately in order to recover any uranium which it might contain. The improvement consists in contacting a slurry, composed of both solution and residue, with the organic solvent prior to filtration. Tbe result is that uranium values contained in the residue are extracted along with the uranium values contained th the solution in one step.

Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska

USGS Publications Warehouse

Taylor, Ryan D.; Graham, Garth E.; Anderson, Eric D.; Selby, David

2014-01-01

This report presents isotopic age data from mineralized granitic plutons in an area of the Alaska Range located approximately 200 kilometers to the west-northwest of Anchorage in southwestern Alaska. Uranium-lead isotopic data and trace element concentrations of zircons were determined for 12 samples encompassing eight plutonic bodies ranging in age from approximately 76 to 57.4 millions of years ago (Ma). Additionally, a rhenium-osmium age of molybdenite from the Miss Molly molybdenum occurrence is reported (approx. 59 Ma). All of the granitic plutons in this study host gold-, copper-, and (or) molybdenum-rich prospects. These new ages modify previous interpretations regarding the age of magmatic activity and mineralization within the study area. The new ages show that the majority of the gold-quartz vein-hosting plutons examined in this study formed in the Late Cretaceous. Further work is necessary to establish the ages of ore-mineral deposition in these deposits.

Advances in soil gas geochemical exploration for natural resources: Some current examples and practices

NASA Astrophysics Data System (ADS)

McCarthy, J. Howard, Jr.; Reimer, G. Michael

1986-11-01

Field studies have demonstrated that gas anomalies are found over buried mineral deposits. Abnormally high concentrations of sulfur gases and carbon dioxide and abnormally low concentrations of oxygen are commonly found over sulfide ore deposits. Helium anomalies are commonly associated with uranium deposits and geothermal areas. Helium and hydrocarbon gas anomalies have been detected over oil and gas deposits. Gases are sampled by extracting them from the pore space of soil, by degassing soil or rock, or by adsorbing them on artificial collectors. The two most widely used techniques for gas analysis are gas chromatography and mass spectrometry. The detection of gas anomalies at or near the surface may be an effective method to locate buried mineral deposits.

EXTRACTION OF URANIUM

DOEpatents

Kesler, R.D.; Rabb, D.D.

1959-07-28

An improved process is presented for recovering uranium from a carnotite ore. In the improved process U/sub 2/O/sub 5/ is added to the comminuted ore along with the usual amount of NaCl prior to roasting. The amount of U/sub 2/O/ sub 5/ is dependent on the amount of free calcium oxide and the uranium in the ore. Specifically, the desirable amount of U/sub 2/O/sub 5/ is 3.2% for each 1% of CaO, and 5 to 6% for each 1% of uranium. The mixture is roasted at about 1560 deg C for about 30 min and then leached with a 3 to 9% aqueous solution of sodium carbonate.

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

PROCESS FOR THE CONCENTRATION OF ORES CONTAINING GOLD AND URANIUM

DOEpatents

Gaudin, A.M.; Dasher, J.

1958-06-10

ABS>A process is described for concentrating certain low grade uranium and gold bearing ores, in which the gangue is mainly quartz. The production of the concentrate is accomplished by subjecting the crushed ore to a froth floatation process using a fatty acid as a collector in conjunction with a potassium amyl xanthate collector. Pine oil is used as the frothing agent.

A brief history of the American radium industry and its ties to the scientific community of its early twentieth century

USGS Publications Warehouse

Landa, E.R.

1993-01-01

Federally funded remedial action projects are presently underway in New Jersey and Colorado at sites containing 226Ra and other radionuclides from radium-uranium ore extraction plants that operated during the early twentieth century. They are but the latest chapter in the story of an American industry that emerged and perished in the span of three decades. Major extraction plants were established in or near Denver (CO), Pittsburgh (PA), and New York City (NY) to process radium from ore that came largely from the carnotite deposits of western Colorado and eastern Utah. The staffs of these plants included some of the finest chemists and physicists in the nation, and the highly-refined radium products found a variety of uses in medicine and industry. The discovery of high-grade pitchblende ores in the Belgian Congo and the subsequent opening of an extraction plant near Antwerp, Belgium, in 1992, however, created an economic climate that put an end to the American radium industry. The geologic, chemical, and engineering information gathered during this era formed the basis of the uranium industry of the later part of the century, while the tailings and residues came to be viewed as environmental problems during the same period.

Development of an extractive spectrophotometric method for estimation of uranium in ore leach solutions using 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) mixture as extractant and 2-(5-bromo-2-pyridylozo)-5-diethyl aminophenol (Br-PADAP) as chromophore

NASA Astrophysics Data System (ADS)

Biswas, Sujoy; Pathak, P. N.; Roy, S. B.

2012-06-01

An extractive spectrophotometric analytical method has been developed for the determination of uranium in ore leach solution. This technique is based on the selective extraction of uranium from multielement system using a synergistic mixture of 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) in cyclohexane and color development from the organic phase aliquot using 2-(5-Bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP) as chromogenic reagent. The absorption maximum (λmax) for UO22+-Br-PADAP complex in organic phase samples, in 64% (v/v) ethanol containing buffer solution (pH 7.8) and 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) complexing agent, has been found to be at 576 nm (molar extinction coefficient, ɛ: 36,750 ± 240 L mol-1 cm-1). Effects of various parameters like stability of complex, ethanol volume, ore matrix, interfering ions etc. on the determination of uranium have also been evaluated. Absorbance measurements as a function of time showed that colored complex is stable up to >24 h. Presence of increased amount of ethanol in colored solution suppresses the absorption of a standard UO22+-Br-PADAP solution. Analyses of synthetic standard as well as ore leach a solution show that for 10 determination relative standard deviation (RSD) is <2%. The accuracy of the developed method has been checked by determining uranium using standard addition method and was found to be accurate with a 98-105% recovery rate. The developed method has been applied for the analysis of a number of uranium samples generated from uranium ore leach solutions and results were compared with standard methods like inductively coupled plasma emission spectrometry (ICPAES). The determined values of uranium concentrations by these methods are within ±2%. This method can be used to determine 2.5-250 μg mL-1 uranium in ore leach solutions with high accuracy and precision.

Technical Report on the Behavior of Trace Elements, Stable Isotopes, and Radiogenic Isotopes During the Processing of Uranium Ore to Uranium Ore Concentrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marks, N. E.; Borg, L. E.; Eppich, G. R.

2015-07-09

The goals of this SP-1 effort were to understand how isotopic and elemental signatures behave during mining, milling, and concentration and to identify analytes that might preserve geologic signatures of the protolith ores. The impurities that are preserved through the concentration process could provide useful forensic signatures and perhaps prove diagnostic of sample origin.

BLENDING LOW ENRICHED URANIUM WITH DEPLETED URANIUM TO CREATE A SOURCE MATERIAL ORE THAT CAN BE PROCESSED FOR THE RECOVERY OF YELLOWCAKE AT A CONVENTIONAL URANIUM MILL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schutt, Stephen M.; Hochstein, Ron F.; Frydenlund, David C.

2003-02-27

Throughout the United States Department of Energy (DOE) complex, there are a number of streams of low enriched uranium (LEU) that contain various trace contaminants. These surplus nuclear materials require processing in order to meet commercial fuel cycle specifications. To date, they have not been designated as waste for disposal at the DOE's Nevada Test Site (NTS). Currently, with no commercial outlet available, the DOE is evaluating treatment and disposal as the ultimate disposition path for these materials. This paper will describe an innovative program that will provide a solution to DOE that will allow disposition of these materials atmore » a cost that will be competitive with treatment and disposal at the NTS, while at the same time recycling the material to recover a valuable energy resource (yellowcake) for reintroduction into the commercial nuclear fuel cycle. International Uranium (USA) Corporation (IUSA) and Nuclear Fuel Services, Inc. (NFS) have entered into a commercial relationship to pursue the development of this program. The program involves the design of a process and construction of a plant at NFS' site in Erwin, Tennessee, for the blending of contaminated LEU with depleted uranium (DU) to produce a uranium source material ore (USM Ore{trademark}). The USM Ore{trademark} will then be further processed at IUC's White Mesa Mill, located near Blanding, Utah, to produce conventional yellowcake, which can be delivered to conversion facilities, in the same manner as yellowcake that is produced from natural ores or other alternate feed materials. The primary source of feed for the business will be the significant sources of trace contaminated materials within the DOE complex. NFS has developed a dry blending process (DRYSM Process) to blend the surplus LEU material with DU at its Part 70 licensed facility, to produce USM Ore{trademark} with a U235 content within the range of U235 concentrations for source material. By reducing the U235 content to source material levels in this manner, the material will be suitable for processing at a conventional uranium mill under its existing Part 40 license to remove contaminants and enable the product to re-enter the commercial fuel cycle. The tailings from processing the USM Ore{trademark} at the mill will be permanently disposed of in the mill's tailings impoundment as 11e.(2) byproduct material. Blending LEU with DU to make a uranium source material ore that can be returned to the nuclear fuel cycle for processing to produce yellowcake, has never been accomplished before. This program will allow DOE to disposition its surplus LEU and DU in a cost effective manner, and at the same time provide for the recovery of valuable energy resources that would be lost through processing and disposal of the materials. This paper will discuss the nature of the surplus LEU and DU materials, the manner in which the LEU will be blended with DU to form a uranium source material ore, and the legal means by which this blending can be accomplished at a facility licensed under 10 CFR Part 70 to produce ore that can be processed at a conventional uranium mill licensed under 10 CFR Part 40.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

WANG,YIFENG; XU,HUIFANG

Correctly identifying the possible alteration products and accurately predicting their occurrence in a repository-relevant environment are the key for the source-term calculation in a repository performance assessment. Uraninite in uranium deposits has long been used as a natural analog to spent fuel in a repository because of their chemical and structural similarity. In this paper, a SEM/AEM investigation has been conducted on a partially alternated uraninite sample from a uranium ore deposit of Shinkolobwe of Congo. The mineral formation sequences were identified: uraninite {yields} uranyl hydrates {yields} uranyl silicates {yields} Ca-uranyl silicates or uraninite {yields} uranyl silicates {yields} Ca-uranyl silicates.more » Reaction-path calculations were conducted for the oxidative dissolution of spent fuel in a representative Yucca Mountain groundwater. The predicted sequence is in general consistent with the SEM observations. The calculations also show that uranium carbonate minerals are unlikely to become major solubility-controlling mineral phases in a Yucca Mountain environment. Some discrepancies between model predictions and field observations are observed. Those discrepancies may result from poorly constrained thermodynamic data for uranyl silicate minerals.« less

Microbial reduction of uranium

USGS Publications Warehouse

Lovley, D.R.; Phillips, E.J.P.; Gorby, Y.A.; Landa, E.R.

1991-01-01

REDUCTION of the soluble, oxidized form of uranium, U(VI), to insoluble U(IV) is an important mechanism for the immobilization of uranium in aquatic sediments and for the formation of some uranium ores1-10. U(VI) reduction has generally been regarded as an abiological reaction in which sulphide, molecular hydrogen or organic compounds function as the reductant1,2,5,11. Microbial involvement in U(VI) reduction has been considered to be limited to indirect effects, such as microbial metabolism providing the reduced compounds for abiological U(VI) reduction and microbial cell walls providing a surface to stimulate abiological U(VI) reduction1,12,13. We report here, however, that dissimilatory Fe(III)-reducing microorganisms can obtain energy for growth by electron transport to U(VI). This novel form of microbial metabolism can be much faster than commonly cited abiological mechanisms for U(VI) reduction. Not only do these findings expand the known potential terminal electron acceptors for microbial energy transduction, they offer a likely explanation for the deposition of uranium in aquatic sediments and aquifers, and suggest a method for biological remediation of environments contaminated with uranium.

Sustainability of uranium mining and milling: toward quantifying resources and eco-efficiency.

PubMed

Mudd, Gavin M; Diesendorf, Mark

2008-04-01

The mining of uranium has long been a controversial public issue, and a renewed debate has emerged on the potential for nuclear power to help mitigate against climate change. The central thesis of pro-nuclear advocates is the lower carbon intensity of nuclear energy compared to fossil fuels, although there remains very little detailed analysis of the true carbon costs of nuclear energy. In this paper, we compile and analyze a range of data on uranium mining and milling, including uranium resources as well as sustainability metrics such as energy and water consumption and carbon emissions with respect to uranium production-arguably the first time for modern projects. The extent of economically recoverable uranium resources is clearly linked to exploration, technology, and economics but also inextricably to environmental costs such as energy/water/chemicals consumption, greenhouse gas emissions, and social issues. Overall, the data clearly show the sensitivity of sustainability assessments to the ore grade of the uranium deposit being mined and that significant gaps remain in complete sustainability reporting and accounting. This paper is a case study of the energy, water, and carbon costs of uranium mining and milling within the context of the nuclear energy chain.

Radiometric surveying for the assessment of radiation dose and radon specific exhalation in underground environment

NASA Astrophysics Data System (ADS)

Bochiolo, M.; Verdoya, M.; Chiozzi, P.; Pasquale, V.

2012-08-01

We performed a radiometric survey for evaluating the natural radioactivity and the related potential hazard level both outdoor and indoor a mine tunnel. The mine is located in a zone of uranium enrichment in the Western Alps (Italy). At first, a γ-ray spectrometry survey of the area surrounding the mine was carried out to define the extent of the ore deposit. Then, spectrometric measurements were performed in the tunnel and rock samples were collected for laboratory analyses. The results point to significant heterogeneity in uranium concentration and consequently in the absorbed dose rate spatial distribution. Spectrometric results in situ and in the laboratory, together with radon air concentration measurements, were used to infer the radon specific exhalation and flow from the mine rocks. The specific exhalation is positively related to the activity concentration of uranium.

Investigation of sulphur isotope variation due to different processes applied during uranium ore concentrate production.

PubMed

Krajkó, Judit; Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Konings, Rudy

The applicability and limitations of sulphur isotope ratio as a nuclear forensic signature have been studied. The typically applied leaching methods in uranium mining processes were simulated for five uranium ore samples and the n ( 34 S)/ n ( 32 S) ratios were measured. The sulphur isotope ratio variation during uranium ore concentrate (UOC) production was also followed using two real-life sample sets obtained from industrial UOC production facilities. Once the major source of sulphur is revealed, its appropriate application for origin assessment can be established. Our results confirm the previous assumption that process reagents have a significant effect on the n ( 34 S)/ n ( 32 S) ratio, thus the sulphur isotope ratio is in most cases a process-related signature.

Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

DOE PAGES

Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael; ...

2014-04-13

In early 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. While searching the laboratory, they discovered a small glass jar labelled “Gamma Source” and containing a green powder. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterize and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive rangemore » of parameters were measured, the key ‘nuclear forensic signatures’ used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.« less

Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia.

PubMed

Keegan, Elizabeth; Kristo, Michael J; Colella, Michael; Robel, Martin; Williams, Ross; Lindvall, Rachel; Eppich, Gary; Roberts, Sarah; Borg, Lars; Gaffney, Amy; Plaue, Jonathan; Wong, Henri; Davis, Joel; Loi, Elaine; Reinhard, Mark; Hutcheon, Ian

2014-07-01

Early in 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. During the search of the laboratory, a small glass jar labelled "Gamma Source" and containing a green powder was discovered. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterise and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive range of parameters were measured, the key 'nuclear forensic signatures' used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael

In early 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. While searching the laboratory, they discovered a small glass jar labelled “Gamma Source” and containing a green powder. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterize and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive rangemore » of parameters were measured, the key ‘nuclear forensic signatures’ used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.« less

Host rocks and their alterations as related to uranium-bearing veins in the United States

USGS Publications Warehouse

Walker, George W.

1956-01-01

This paper, dealing with the different kinds of host rocks and their alterations associated with uranium-bearing veins in the United States, is a chapter of a comprehensive report entitled , "Geology of uranium-bearing vein deposits in the United States," in preparation by George W. Walker, Frank W. Osterwald, and others. The comprehensive report will include detailed information on tectonic and structural setting, kinds of host rocks, wall-rock alteration, mineralogy, physical characteristics, processes of deposition, and concepts of origin of uraniferous veins; but, because it will not be completed until sometime in the future, some chapters of the report are being transmitted as they are finished. Part of an introductory chapter to the comprehensive report entitled, "Classification and distribution of uranium-bearing veins in the United States" (Walker and Osterwald, 1956) has already been transmitted; several of the terms used herein are defined in the introductory chapter. Data included in this chapter demonstrate that uranium-bearing veins are: 1) in rocks of nearly all textural, chemical, and mineralogic types; 2) most abundant in holocrystalline, commonly equigranular, igeneous and metamorphic rocks characterized by a moderate to high silica content and and by similar physical properties. Although some of the physiochemical properties of the host rocks are discussed in terms of favorability or nonfavoribility for uranium deposition, the principal purpose of this chapter is to establish the petroloic environment in which uranium-bearing veins have been found. Because favorability or nonfavorability of host rocks is related complexly to the chemistry of ore solutions and to methods or uranium transport and deposition, several hypothetical processes of transport and deposition have been referred to briefly; these and other hypotheses will be outlines and discussed in greater detail in a subsequent chapter. The compilation of data leading to this report and its preparation by a member of the Uranium Research and Resource Section, U.S. Geological Survey, was done on behalf of the Division of Raw Materials, U.S. Atomic Energy Commission. The report is based on both published and unpublished information collected principally by personnel of the U.S. Geological Survey, the U.S. Atomic Energy Commission or its predecessor organization, the Manhattan Engineer District, and to a lesser extent by staff members of other Federal or State agencies and by geologists in private industry. Information concerning foreign uranium-bearing vein deposits has been extracted almost exclusively from published reports; references to these and other data are included at appropriate places.

The Olympic Dam copper-uranium-gold deposit, Roxby Downs, South Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, D.E.; Hudson, G.R.T.

1983-08-01

The Olympic Dam copper-uranium-gold deposit appears to be a new type of strata-bound sediment-hosted ore deposit. It is located 650 km north-northwest of Adelaide in South Australia and was discovered in 1975. It has an areal extent exceeding 20 km/sup 2/ with vertical thicknesses of mineralization up to 350 m. The deposit is estimated to contain in excess of 2,000 million metric tons of mineralized material with an average grade of 1.6 percent copper, 0.06 percent uranium oxide, and 0.6 g/metric ton gold. The deposit occurs in the basement beneath 350 m of unmineralized, flat-lying Adelaidean (late Proterozoic) to Cambrianmore » sediments in the Stuart shelf region of South Australia. The host rocks of the deposit are unmetamorphosed and are probably younger than 1,580 m.y. The deposit is spatially related to coincident gravity and magnetic anomalies and the intersection of west-northwest- and north-northwest-trending lineaments. The Proterozoic sediments comprising the local basement sequence are predominantly sedimentary breccias ranging from matrix-poor granite breccias to matrix-rich polymict breccias containing clasts of a variety of rock types. This sequence is over 1 km thick and has been divided into two main units--the Olympic Dam Formation and the Greenfield Formation. The Olympic Dam Formation has five members, three of which are matrix rich. The Greenfield Formation has three members, the lower two being very hematite rich while the upper has a significant volcanic component. Pervasive hematite, chlorite, and sericite alteration of varying intensity affects all the basement sequence.« less

Geology and mineral deposits of the Carlile quadrangle, Crook County, Wyoming

USGS Publications Warehouse

Bergendahl, M.H.; Davis, R.E.; Izett, G.A.

1961-01-01

The Carlile quadrangle-is along the northwestern flank of the Black Hills uplift in Crook County, Wyo. The area-is primarily one of canyons and divides that are a result of downcutting by the Belle Fourche River and its tributaries through an alternating succession of sandstone, siltstone, and mudstone or shale beds. The present topography is also influenced by the regional structure, as reflected by the beds that dip gently westward and by the local structural features such as anticlines, domes, synclines, basins, and terraces, which are superimposed upon the regional setting. Rocks exposed include shale and thin limestone and sandstone beds belonging to the Redwater shale member of the Sundance formation and to the Morrison formation, both of Late Jurassic age; sandstone, siltstone, and mudstone of the Lakota and Fall River formations of Early Cretaceous age; and shale and sandstone of the Skull Creek shale, Newcastle sandstone, and Mowry shale, also of Early Cretaceous age. In the southwestern part of the quadrangle rocks of the Upper Cretaceous series are exposed. These include the Belle Fourche shale, Greenhorn formation, and Carlile shale. Gravel terraces, landslide debris, and stream alluvium comprise the surficial deposits. The Lakota and Fall River formations, which make up the Iriyan Kara group, contain uranium deposits locally in the northern Black Hills. These formations were informally subdivided in order to show clearly the vertical and lateral distribution of the sandstone, siltstone, and mudstone facies within them.The Lakota was subdivided into a sandstone unit and an overlying mudstone unit; the Fall River was subdivided, in ascending order, into a siltstone unit, a mudstone unit, a sandstone unit, and an upper unit. The lithologic character of the Lakota changes abruptly locally, and the units are quite inconsistent with respect to composition, thickness, and extent. This is in contrast to a notable consistency in the lithologic character and thickness among all the Fall River units, with the exception of the upper unit. Petrographic studies on selected samples of units from both formations show differences in composition between Lakota and Fall River rocks.The Carlile quadrangle lies immediately east of the monocline that marks the outer limit of the Black Hills uplift, and the rocks in this area have a regional dip of less than 2° outward from the center of the uplift. Superimposed upon the regional uplift are many subordinate structural features anticlines, synclines, domes, basins, and terraces which locally modify the regional features. The most pronounced of these subordinate structural features are the doubly-plunging Pine Ridge, Oil Butte, and Dakota Divide anticlines, and the Eggie Creek syncline. Stress throughout the area was relieved almost entirely through folding; only a few small nearly vertical normal faults were found within the quadrangle.Uranium has been mined from the Carlile deposit, owned by the Homestake Mining Co. The ore minerals, carnotite and tyuyamnuite occur in a sandstone lens that is enclosed within relatively impermeable clayey beds in the mudstone unit of the Lakota formation. The ore also includes unidentified black vanadium minerals and possibly coffinite. Uranium minerals are more abundant in and adjacent to thicker carbonaceous and silty seams in the sandstone lens. A mixture of fine-grained calcium carbonate and calcium sulfate fills the interstices between detrital quartz grains in mineralized sandstone. Selenium and arsenic are more abundant in samples that are high in uranium. Drilling on Thorn Divide about 1 mile west of the Carlile mine has roughly outlined concentrations of a sooty black uranium mineral associated with pyrite In two stratigraphic intervals of the Lakota formation. One is in the same sandstone lens that contains the ore at the Carlile mine; the other is in conglomeratic sandstone near the base of the Lakota. These deposits are relatively deep, and no mining has been attempted. The mineralogy of the Carlile deposits and the lithologic features of the sandstone host rock suggest that uranium and vanadium were transported in the high-valent state by carbonate or sulfate solutions, were extracted from solution by organic material, and were reduced to low-valent states to form an original assemblage of oxides and silicates. These primary minerals were oxidized in place, and the present carnotite-tyuyamunite assemblage was formed. In general, radioactivity analyses correspond fairly closely with chemical analyses of uranium, thus it is believed that only minor solution and migration of uranium has occurred since the present suite of oxidized minerals was formed. The factors responsible for ore localization are not clear, but probably a combination of three lithologic and structural elements contributed to provide a favorable environment for precipitating uranium from aqueous solutions: abundant carbonaceous material or pyrite in a thin, permeable sandstone enclosed within relatively thick impermeable clays; local structural basins; and a regional structural setting involving a broad syncline between two anticlines. The structural features controlled the regional flow of ground water and the lithologic features controlled the local rate of flow and provided the proper chemical environment for uranium deposition. Bentonite has been mined from an opencut in the Mowry shale in the southwest part of the quadrangle. A bentonite bed in the Newcastle sandstone also seems to be of minable thickness and quality. Exploration for petroleum has been unsuccessful within the quadrangle; however, some wells that yielded oil were recently drilled on small anticlines to the west and southeast. It is possible that similar structural features in the Carlile area, that were previously overlooked, may be equally productive.

RECOVERY OF URANIUM FROM CARBONATE LEACH LIQUORS

DOEpatents

Wilson, H.F.

1958-07-01

An improved process is described for the recovery of uranium from vanadifrous ores. In the prior art such ores have been digested with alkali carbonate solutions at a pH of less than 10 and then contacted with a strong base anion exchange resin to separate uranium from vanadium. It has been found that if the exchamge resin feed solution has its pH adjusted to the range 10.8 to 11.8, that vanadium adsorption on the resin is markedly decreased and the separation of uranium from the vanadium is thereby improved.

Geodynamic simulation of ore-bearing geological structural units by the example of the Strel'tsovka uranium ore field

NASA Astrophysics Data System (ADS)

Petrov, V. A.; Leksin, A. B.; Pogorelov, V. V.; Rebetsky, Yu. L.; San'kov, V. A.; Ashurkov, S. V.; Rasskazov, I. Yu.

2017-05-01

Information on designing a 3D integrated model of the deflected mode (DM) of rock massif near the Strel'tsovka uranium ore field (SUOF) in the southeastern Transbaikal region is presented in the paper. This information is based on the contemporary stresses estimated by geostructural and tectonophysical techniques and by studying the seismotectonic deformation of the Earth's surface using the data on earthquake source mechanisms and GPS geodesy focused on the recognition of active faults. A combination of the results of geostructural, geophysical, geotectonic, and petrophysical research, as well as original maps of faulting and the arrangement of seismic dislocations and seismotectonic regimes (stress tensors), allowed us to design models of the structure, properties, and rheological links of the medium and to determine the boundary conditions for numerical tectonophysical simulation using the method of terminal elements. The computed 2D and 3D models of the state of the rock massif have been integrated into 3D GIS created on the basis of the ArcGIS 10 platform with an ArcGIS 3D-Analyst module. The simulation results have been corroborated by in situ observations on a regional scale (the Klichka seismodislocation, active from the middle Pliocene to date) and on a local scale (heterogeneously strained rock massif at the Antei uranium deposit). The development of a regional geodynamic model of geological structural units makes it possible to carry out procedures to ensure the safety of mining operations under complex geomechanical conditions that can expose the operating mines and mines under construction, by the Argun Mining and Chemical Production Association (PAO PPGKhO) on a common methodical and geoinformational platform, to the hazards of explosions, as well as to use the simulation results aimed at finding new orebodies to assess the flanks and deep levels of the ore field.

The future of Yellowcake: a global assessment of uranium resources and mining.

PubMed

Mudd, Gavin M

2014-02-15

Uranium (U) mining remains controversial in many parts of the world, especially in a post-Fukushima context, and often in areas with significant U resources. Although nuclear proponents point to the relatively low carbon intensity of nuclear power compared to fossil fuels, opponents argue that this will be eroded in the future as ore grades decline and energy and greenhouse gas emissions (GGEs) intensity increases as a result. Invariably both sides fail to make use of the increasingly available data reported by some U mines through sustainability reporting - allowing a comprehensive assessment of recent trends in the energy and GGE intensity of U production, as well as combining this with reported mineral resources to allow more comprehensive modelling of future energy and GGEs intensity. In this study, detailed data sets are compiled on reported U resources by deposit type, as well as mine production, energy and GGE intensity. Some important aspects included are the relationship between ore grade, deposit type and recovery, which are crucial in future projections of U mining. Overall, the paper demonstrates that there are extensive U resources known to meet potential short to medium term demand, although the future of U mining remains uncertain due to the doubt about the future of nuclear power as well as a range of complex social, environmental, economic and some site-specific technical issues. Copyright © 2013 Elsevier B.V. All rights reserved.

Radon emanation from low-grade uranium ore.

PubMed

Sahu, Patitapaban; Mishra, Devi Prasad; Panigrahi, Durga Charan; Jha, Vivekanand; Patnaik, R Lokeswara

2013-12-01

Estimation of radon emanation in uranium mines is given top priority to minimize the risk of inhalation exposure due to short-lived radon progeny. This paper describes the radon emanation studies conducted in the laboratory as well as inside an operating underground uranium mine at Jaduguda, India. Some of the important parameters, such as grade/(226)Ra activity, moisture content, bulk density, porosity and emanation fraction of ore, governing the migration of radon through the ore were determined. Emanation from the ore samples in terms of emanation rate and emanation fraction was measured in the laboratory under airtight condition in glass jar. The in situ radon emanation rate inside the mine was measured from drill holes made in the ore body. The in situ(222)Rn emanation rate from the mine walls varied in the range of 0.22-51.84 × 10(-3) Bq m(-2) s(-1) with the geometric mean of 8.68 × 10(-3) Bq m(-2) s(-1). A significant positive linear correlation (r = 0.99, p < 0.001) between in situ(222)Rn emanation rate and the ore grade was observed. The emanation fraction of the ore samples, which varied in the range of 0.004-0.089 with mean value of 0.025 ± 0.02, showed poor correlation with ore grade and porosity. Empirical relationships between radon emanation rate and the ore grade/(226)Ra were also established for quick prediction of radon emanation rate from the ore body. Copyright © 2013 Elsevier Ltd. All rights reserved.

The midcontinent of the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratt, W.P.; Sims, P.K.

1990-01-01

The Olympic Dam (Roxby Downs) deposit in South Australia is one of the world's largest ore deposits, containing an estimated 32 million tonnes Cu, 1.2 million tonnes of uranium oxide, 1.2 million kg Au, and significant concentrations of rare-earth elements and silver. Host rocks are multistage breccias containing a large component of granitic and some possible felsic debris in a hydrothermal iron oxide-dominated matrix. The Precambrian basement in the Midcontinent region, especially the St. Francois and Spavinaw Proterozoic anorogenic granitic terranes in and adjacent to southern Missouri, may have potential for an olympic dam-type deposit. In February 1988, the U.S.more » Geological Survey convened a workshop in Denver, Colo., to review current data and hypotheses on the type deposit and on the permissive Midcontinent terranes and to design plans for a research project to try to identify potential olympic dam target regions in the Midcontinent. This book presents four of the papers from the workshop (three full texts and one abstract) and one modified paper, as well as the integrated project proposal. An epilogue contains two short papers constituting an update on one aspect of the project proposal: mapping of the possibly analogous Pea Ridge iron ore deposit of Southeast Missouri.« less

Geology of the Gateway quadrangle, Mesa county Colorado

USGS Publications Warehouse

Cater, Fred W.

1953-01-01

The Gateway quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by hih-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as "Uruvan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Egnar quadrangle, Dolores and San Miguel counties, Colorado

USGS Publications Warehouse

Cater, Fred W.; Bush, A.L.; Bell, Henry

1954-01-01

The Egnar quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by hih-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as "Uruvan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Hamm Canyon quadrangle, Colorado

USGS Publications Warehouse

Cater, Fred W.

1953-01-01

The Hamm Canyon quadrangle is on eof eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Davis Mesa quadrangle, Colorado

USGS Publications Warehouse

Cater, Fred W.; Bryner, Leonid

1953-01-01

The Davis Mesa quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by hih-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as "Uruvan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Joe Davis Hill quadrangle, Dolores and San Miguel counties, Colorado

USGS Publications Warehouse

Cater, Fred W.; Bell, Henry

1953-01-01

The Joe Davis Hill quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by hih-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Pine Mountain quadrangle, Mesa county, Colorado

USGS Publications Warehouse

Cater, Fred W.

1953-01-01

The Pine Mountain quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from Paleozoic to Quaternary. Over mush of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confines to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in sizer from irregular masses containing only a few ton of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Naturita NW quadrangle, Colorado

USGS Publications Warehouse

Cater, Fred W.; Vogel, J.D.

1953-01-01

The Naturita NW quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles were mapped by the U.S. Geological Survey on behalf of the U.S. Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear ro be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Calamity Mesa quadrangle, Mesa county, Colorado

USGS Publications Warehouse

Cater, Fred W.; Stager, Harold K.

1953-01-01

The Calamity Mesa quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks the range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Horse Range Mesa quadrangle, Colorado

USGS Publications Warehouse

Cater, Fred W.; Bush, A.L.; Bell, Henry; Withington, C.F.

1953-01-01

The Horse Range Mesa quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of the quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary strictures in sandstones of favorable composition.

Geology of the Uravan quadrangle, Montrose county, Colorado

USGS Publications Warehouse

Cater, Fred W.; Butler, A.P.; McKay, E.J.; Boardman, Robert L.

1954-01-01

The Uravan quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of the southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to the related to certain sedimentary structures in sandstones of favorable composition.

QUANTITATIVE DETERMINATION OF THE URANIUM CONTENT OF URANIUM ORES TECHNOLOGICAL PRODUCTS BY ION EXCHANGE-COMPLEXON SEPARATION (in Hungarian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fodor, M.

An ion exchange-complexion separation meihod was developed for the removal of interfering elements in the determination of the uranium content of recovery solutions. By adding (ethylenediamine)tetraacetic acid to the solution, most of the interfering elements can be brought into an anionic complex. Adjusting the soluiion to pH 7 and letting it pass through an Amberlite IRC-50 type cation exchanger of hydrogen form, the uranium remains on the column whereas the interfering elements pass into the effluent. The method was successfully applied in analyzing the recovery solutions of uranium ores. (auth)

Geochemical and mineralogical studies of a South Texas roll-front uranium deposit

USGS Publications Warehouse

Goldhaber, Martin B.; Reynolds, Richard L.

1977-01-01

Core samples from a roll-front uranium deposit in south Texas have been analyzed for iron sulfide content and mineralogy, organic carbon content and the abundance of carbonate, iron, manganese and titanium. Sulfide occurs almost exclusively as the iron disulfides pyrite and marcasite, in concentrations as high as 2 percent of the coarse (>62 ?m) fraction. Marcasite is particularly abundant relative to pyrite in the vicinity of the roll front. Because marcasite precipitation requires acidic pH's and the most likely mechanism for generating a low pH is oxidation of preore sulfide, it is argued that marcasite formation is, at least in part, related to roll-front development. Organic carbon analyses from various representative parts of the deposit are uniformly low (<0.1 percent C). This is taken to imply that sulfate reducing bacteria were not involved in either initial sulfidation of the host rock or during later sulfidization that was related to the ore-forming episode. carbonate minerals, such as calcite, are quite abundant, but appear to have formed after the ore. The overall abundance of iron apparently is not systematically related to position with respect to the roll front, whereas manganese probably is concentrated near the redox interface. Titanium like iron does not show a systematic relationship to position about the roll. However, titanium is systematically more abundant in the fine fraction (462 ?m) relative to the coarse fraction with distance downdip. This reflects a progressively more intense alteration of precursor iron titanium oxide minerals to fine-grained TiO2.

Preliminary report on the Comet area, Jefferson County, Montana

USGS Publications Warehouse

Becraft, George Earle

1953-01-01

Several radioactivity anomalies and a few specimens of sooty pitchblende and other uranium minerals have been found on the mine dumps of formerly productive base- and precious-metal mines along the Comet-Gray Eagle shear zone in the Comet area in southwestern Montana. The shear zone is from 50 to 200 feet wide and has been traced for at least 5? miles. It trends N. 80 ? W. across the northern part of the area and cuts the quartz monzonitic rocks of the Boulder batholith and younger silicic intrusive rocks, as well as prebatholithic volcanic rocks, and is in turn cut by dacite and andesite dikes. The youngest period of mineralization is represented by chalcedonic vein zones comprising one or more discontinuous stringers and veins of cryptocrystalline silica in silicified quartz monzonite and in alaskite that has not been appreciably silicified. In some places these zones contain no distinct chalcedonic veins but are represented only by silicified quartz monzonite. These zones locally contain uranium in association with very small amounts of pyrite, galena, ruby silver, arqentite, native silver, molybdenite, chalcopyrite, arsenopyrite, and barite. At the Free Enterprise mine, uranium has been produced from a narrow chalcedonic vein that contains disseminated secondary uranium minerals and local small pods of pitchblende and also from disseminated secondary uranium ,minerals in the adjacent quartz monzonite. Undiscovered deposits of uranium ore may occur spatially associated with the base- and precious-metal deposits along the Comet-Gray Eagle shear zone and with chalcedonic vein zones similar to the Free Enterprise.

Development of an extractive spectrophotometric method for estimation of uranium in ore leach solutions using 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) mixture as extractant and 2-(5-bromo-2-pyridylozo)-5-diethyl aminophenol (Br-PADAP) as chromophore.

PubMed

Biswas, Sujoy; Pathak, P N; Roy, S B

2012-06-01

An extractive spectrophotometric analytical method has been developed for the determination of uranium in ore leach solution. This technique is based on the selective extraction of uranium from multielement system using a synergistic mixture of 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and tri-n-octyl phosphine oxide (TOPO) in cyclohexane and color development from the organic phase aliquot using 2-(5-Bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP) as chromogenic reagent. The absorption maximum (λ(max)) for UO(2)(2+)-Br-PADAP complex in organic phase samples, in 64% (v/v) ethanol containing buffer solution (pH 7.8) and 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) complexing agent, has been found to be at 576 nm (molar extinction coefficient, ɛ: 36,750 ± 240 L mol(-1)cm(-1)). Effects of various parameters like stability of complex, ethanol volume, ore matrix, interfering ions etc. on the determination of uranium have also been evaluated. Absorbance measurements as a function of time showed that colored complex is stable up to > 24h. Presence of increased amount of ethanol in colored solution suppresses the absorption of a standard UO(2)(2+)-Br-PADAP solution. Analyses of synthetic standard as well as ore leach a solution show that for 10 determination relative standard deviation (RSD) is < 2%. The accuracy of the developed method has been checked by determining uranium using standard addition method and was found to be accurate with a 98-105% recovery rate. The developed method has been applied for the analysis of a number of uranium samples generated from uranium ore leach solutions and results were compared with standard methods like inductively coupled plasma emission spectrometry (ICPAES). The determined values of uranium concentrations by these methods are within ± 2%. This method can be used to determine 2.5-250 μg mL(-1) uranium in ore leach solutions with high accuracy and precision. Copyright © 2012 Elsevier B.V. All rights reserved.

Uranophane at Silver Cliff mine, Lusk, Wyoming

USGS Publications Warehouse

Wilmarth, Verl R.; Johnson, D.H.

1954-01-01

The uranium deposit at the Silver Cliff mine near Lusk, Wyo., consists primarily of uranophane which occurs as fracture fillings and small replacement pockets in faulted and fractured calcareous sandstone of Cambrian (?) age. The country rock in the vicinity of the mine is schist of pre-Cambrian age intruded by pegmatite dikes and is unconformably overlain by almost horizontal sandstone of Cambrian(?) age. The mine is on the southern end of the Lusk Dome, a local structure probably related to the Hartville uplift. In the immediate vicinity of the mine, the dome is cut by the Silver Cliff fault, a north-trending high-angle reverse fault about 1,200 feet in length with a stratigraphic throw of 70 feet. Uranophane, metatorbernite, pitchblende, calcite, native silver, native copper, chalcocite, azurite, malachite, chrysocolla, and cuprite have been deposited in fractured sandstone. The fault was probably mineralized throughout its length, but because of erosion, the mineralized zone is discontinuous. The principal ore body is about 800 feet long. The width and depth of the mineralized zone are not accurately known but are at least 20 feet and 60 feet respectively. The uranium content of material sampled in the mine ranges from 0.001 to 0.23 percent uranium, whereas dump samples range from 0.076 to 3.39 percent uranium.

PROCESS FOR THE RECOVERY OF URANIUM FROM PHOSPHATIC ORE

DOEpatents

Long, R.L.

1959-04-14

A proccss is described for the recovery of uranium from phosphatic products derived from phosphatic ores. It has been discovered that certain alkyl phosphatic, derivatives can be employed in a direct solvent extraction operation to recover uranium from solid products, such as superphosphates, without first dissolving such solids. The organic extractants found suitable include alkyl derivatives of phosphoric, pyrophosphoric, phosof the derivative contains from 4 to 7 carbon atoms. A diluent such as kerosene is also used.

46 CFR 148.04-1 - Radioactive material, Low Specific Activity (LSA).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Radioactive material, Low Specific Activity (LSA). 148... § 148.04-1 Radioactive material, Low Specific Activity (LSA). (a) Authorized materials are limited to: (1) Uranium or thorium ores and physical or chemical concentrates of such ores; (2) Uranium metal...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

A Record of Uranium-Series Transport in Fractured, Unsaturated Tuff at Nopal I, Sierra Peña Blanca, Chihuahua, Mexico

NASA Astrophysics Data System (ADS)

Denton, J.; Goldstein, S. J.; Paviet, P.; Nunn, A. J.; Amato, R. S.; Hinrichs, K. A.

2015-12-01

In this study we utilize U-series disequilibria measurements to investigate mineral fluid interactions and the role fractures play in the geochemical evolution of an analogue for a high level nuclear waste repository, the Nopal I uranium ore deposit. Samples of fracture-fill materials have been collected from a vertical drill core and surface fractures. High uranium concentrations in these materials (12-7700 ppm) indicate U mobility and transport from the deposit in the past. U concentrations generally decrease with horizontal distance away from the ore deposit but show no trend with depth. Isotopic activity ratios indicate a complicated geochemical evolution in terms of the timing and extent of actinide mobility, possibly due to changing environmental (redox) conditions over the history of the deposit. 234U/238U activity ratios are generally distinct from secular equilibrium and indicate some degree of open system U behavior during the past 1.2 Ma. However, calculated closed system 238U-234U-230Th model ages are generally >313 ka and >183 ka for the surface fracture and drill core samples respectively, suggesting closed system behavior for U and Th over this most recent time period. Whole rock isochrons drawn for the drill core samples show that at two of three depths fractures have remained closed with respect to U and Th mobility for >200 ka. However, open system behavior for U in the last 350 ka is suggested at 67 m depth. 231Pa/235U activity ratios within error of unity suggest closed system behavior for U and Pa for at least the past 185 ka. 226Ra/230Th activity ratios are typically <1 (0.7-1.2), suggesting recent (<8 ka) radium loss and mobility due to ongoing fluid flow in the fractures. Overall, the mainly closed system behavior of U-Th-Pa over the past ~200 ka provides one indicator of the geochemical immobility of these actinides over long time-scales for potential nuclear waste repositories sited in fractured, unsaturated tuff.

Quartz-pebble-conglomerate gold deposits: Chapter P in Mineral deposit models for resource assessment

USGS Publications Warehouse

Taylor, Ryan D.; Anderson, Eric D.

2018-05-17

Quartz-pebble-conglomerate gold deposits represent the largest repository of gold on Earth, largely due to the deposits of the Witwatersrand Basin, which account for nearly 40 percent of the total gold produced throughout Earth’s history. This deposit type has had a controversial history in regards to genetic models. However, most researchers conclude that they are paleoplacer deposits that have been modified by metamorphism and hydrothermal fluid flow subsequent to initial sedimentation.The deposits are found exclusively within fault-bounded depositional basins. The periphery of these basins commonly consists of granite-greenstone terranes, classic hosts for lode gold that source the detrital material infilling the basin. The gold reefs are typically located along unconformities or, less commonly, at the top of sedimentary beds. Large quartz pebbles and heavy-mineral concentrates are found associated with the gold. Deposits that formed prior to the Great Oxidation Event (circa 2.4 giga-annum [Ga]) contain pyrite, whereas younger deposits contain iron oxides. Uranium minerals and hydrocarbons are also notable features of some deposits.Much of the gold in these types of deposits forms crystalline features that are the product of local remobilization. However, some gold grains preserve textures that are undoubtedly of detrital origin. Other heavy minerals, such as pyrite, contain growth banding that is truncated along broken margins, which indicates that they were transported into place as opposed to forming by in situ growth in a hydrothermal setting.The ore tailings associated with these deposits commonly contain uranium-rich minerals and sulfides. Oxidation of the sulfides releases sulfuric acid and mobilizes various metals into the environment. The neutralizing potential of the tailings is minimal, since carbonate minerals are rare. The continuity of the tabular ore bodies, such as those of the Witwatersrand Basin, has allowed these mines to be the deepest in the world. The extreme depths create engineering complications and safety issues for the miners, such as rock bursts as a result of pressure release.The richness of these deposits makes them a desirable exploration target. However, the likelihood of future discoveries is minimal. Small deposits found in the United States include those found at Nemo in the Black Hills of South Dakota and Deep Lake in the Sierra Madre of Wyoming.

Comparison method for uranium determination in ore sample by inductively coupled plasma optical emission spectrometry (ICP-OES).

PubMed

Sert, Şenol

2013-07-01

A comparison method for the determination (without sample pre-concentration) of uranium in ore by inductively coupled plasma optical emission spectrometry (ICP-OES) has been performed. The experiments were conducted using three procedures: matrix matching, plasma optimization, and internal standardization for three emission lines of uranium. Three wavelengths of Sm were tested as internal standard for the internal standardization method. The robust conditions were evaluated using applied radiofrequency power, nebulizer argon gas flow rate, and sample uptake flow rate by considering the intensity ratio of the Mg(II) 280.270 nm and Mg(I) 285.213 nm lines. Analytical characterization of method was assessed by limit of detection and relative standard deviation values. The certificated reference soil sample IAEA S-8 was analyzed, and the uranium determination at 367.007 nm with internal standardization using Sm at 359.260 nm has been shown to improve accuracy compared with other methods. The developed method was used for real uranium ore sample analysis.

VOLATILE CHLORIDE PROCESS FOR THE RECOVERY OF METAL VALUES

DOEpatents

Hanley, W.R.

1959-01-01

A process is presented for recovering uranium, iron, and aluminum from centain shale type ores which contain uranium in minute quantities. The ore is heated wiih a chlorinating agent. such as chlorine, to form a volatilized stream of metal chlorides. The chloride stream is then passed through granular alumina which preferentially absorbs the volatile uranium chloride and from which the uranium may later be recovered. The remaining volatilized chlorides, chiefly those of iron and aluminum, are further treated to recover chlorine gas for recycle, and to recover ferric oxide and aluminum oxide as valuable by-products.

MINING METHODS AND COSTS, CALYX NOS. 3 AND 8 URANIUM MINES, TEMPLE MOUNTAIN DISTRICT, EMERY COUNTY, UTAH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dare, W.L.

1957-04-01

Descriptions are given of the Calyx No. 3 mine operated by American Reduc Uranium Corp. and Calyx No. 8 operated by Cline Co. The deposits are composed of numerous small, irregular bodies and are worked through 36 inch Calyx drill holes. The U--V ores are concentrated chiefly in the lower 30 feet of the Moss Back sandstone. In general it follows the strnta. The mine is worked by open stoping with random pillar support. The operations and mining practices of these two mines are very similar and typify the mining methods and practioes used by many small U producers onmore » the Colorado Plateau. (R.V.J.)« less

ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

DOEpatents

Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

1957-11-12

A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

Uranium ores and depleted uranium in the environment, with a reference to uranium in the biosphere from the Erzgebirge/Sachsen, Germany.

PubMed

Meinrath, A; Schneider, P; Meinrath, G

2003-01-01

The Erzgebirge ('Ore Mountains') area in the eastern part of Germany was a major source of uranium for Soviet nuclear programs between 1945 and 1989. During this time, the former German Democratic Republic became the third largest uranium producer in the world. The high abundance of uranium in the geological formations of the Erzgebirge are mirrored in the discovery of uranium by M. Klaproth close to Freiberg City in 1789 and the description of the so-called 'Schneeberg' disease, lung cancer caused in miners by the accumulation of the uranium decay product, radon, in the subsurfaces of shafts. Since 1991, remediation and mitigation of uranium at production facilities, rock piles and mill tailings has taken place. In parallel, efforts were initiated to assess the likely adverse effects of uranium mining to humans. The costs of these activities amount to about 6.5 10(9) Euro. A comparison with concentrations of depleted uranium at certain sites is given.

LEACHING OF URANIUM ORES USING ALKALINE CARBONATES AND BICARBONATES AT ATMOSPHERIC PRESSURE

DOEpatents

Thunaes, A.; Brown, E.A.; Rabbits, A.T.; Simard, R.; Herbst, H.J.

1961-07-18

A method of leaching uranium ores containing sulfides is described. The method consists of adding a leach solution containing alkaline carbonate and alkaline bicarbonate to the ore to form a slurry, passing the slurry through a series of agitators, passing an oxygen containing gas through the slurry in the last agitator in the series, passing the same gas enriched with carbon dioxide formed by the decomposition of bicarbonates in the slurry through the penultimate agitator and in the same manner passing the same gas increasingly enriched with carbon dioxide through the other agitators in the series. The conditions of agitation is such that the extraction of the uranium content will be substantially complete before the slurry reaches the last agitator.

Results of exploration at the Old Leyden coal mine, Jefferson County, Colorado

USGS Publications Warehouse

Gude, A.J.; McKeown, F.A.

1953-01-01

Six diamond core holes totaling 2, 201 feet were drilled by the. U, S. Bureau of Mines under contract to the U. S. Atomic Energy Commission at the Old Leyden coal mine, Jefferson County, Colo. The holes were spotted on the basis of geologic mapping by the U. S. Geological survey and were drilled to explore the lateral and downward extent of a uranium-bearing coal and the associated carnotite deposits in the adjacent sandstone° The data obtained from the diamond-core holes helped to explain the geology and structural control of the deposit. The uranium is most abundant in a coal bed that in places has been brecciated by shearing. and then altered to a hard, dense, and silicified rock. The uraniferous coal is in the nearly vertical beds of the Laramie formation of Upper Cretaceous age. Small lenticular bodies of uraniferous material, 50 feet long, 25 to 30 feet wide, and 2 to 4 feet thick, occur at intervals in the coal and silicified coal over a strike length of about 800 feet. These bodies contain 0.10 to 0.50 percent uranium. Data obtained from the drilling indicate a discontinuous radioactive zone between these higher-grade bodies; assays of samples from the cores range from 0.001 to 0.10 percent uranium. All drill holes were probed by Survey and A. E. C. logging equipment and showed anomalies where the core assayed more than 0.005 percent uranium. Material of ore grade--0.10 percent uranium--was found in one core; the rock in the other five holes was of lower grade. The presence of the radioactive zone in all holes suggests, however, that uranium is distributed irregularly in a southerly plunging deposit which is exposed in the adit, on the outcrop, and in other diamond-drill holes that were put down by the lessee.

Assessment of natural radioactivity in aquifer medium bearing uranium ores in Koprubasi, Turkey

NASA Astrophysics Data System (ADS)

Simsek, Celalettin

2008-10-01

Koprubasi, located within Manisa Province near the Izmir, is the biggest uranium mine where uranium ores originate from Neogene aged altered sandstone and conglomerate layers. The main objective of this study is to determine the radiation hazard associated with radioactivity levels of uranium ores, and the rocks and sediments around Koprubasi. In this regard, measured activity levels of 226Ra, 232Th and 40K were compared with world averages. The average activity levels of 226 Ra, 232Th and 40K were measured to be 5369.75, 124.78 and 10.0 Bq/kg in uranium ores, 24.32, 52.94 and 623.38 Bq/kg in gneiss, 46.24, 45.13 and 762.26 Bq/kg in sandstone and conglomerate, 73.11, 43.15 and 810.65 Bq/kg in sediments, respectively. All samples have high 226Ra and 40K levels according to world average level. As these sediments are used as construction materials and in agricultural activities within the study area, the radiation hazard are calculated by using dose rate (D), annual effective dose rate (He), radium equivalent activity (Raeq) and radiation hazard index (Iyr). All the samples have Raeq levels that are lower than the world average limit of 370 Bq/kg. On the other hand, D, He and Iyr values are higher than world average values. These results indicate that the uranium ores in the Koprubasi is the most important contributor to the natural radiation level. The radioactivity levels of sediments and rocks make them unsuitable for use as agricultural soil and as construction materials. Moreover, it is determined that shallow groundwater in sediments and deep groundwater in conglomerate rocks and also surface water sources in the Koprubasi have high 226Ra content. According to environmental radioactive baseline, some environmental protection study must be taken in Koprubasi uranium site and the environment.

Economic geology of the Central City district, Gilpin County, Colorado

USGS Publications Warehouse

Sims, P.K.; Drake, Avery A.; Tooker, E.W.

1963-01-01

The Central City district, in Gilpin County, Colo., is on the east flank of the Front Range, about 30 miles west of Denver. The district is the most important mining camp in the Front Range mineral belt, and has yielded more than $100 million worth of gold, silver, uranium, and base-metal ores since 1859. Gold accounts for about 85 percent of the dollar value of the ore. In recent years mining activity has been slack but from 1950 to 1955 the search for uranium ores stimulated prospecting and development.

Geology of Bull Canyon quadrangle, Montrose and San Miguel counties, Colorado

USGS Publications Warehouse

Cater, Fred W.

1953-01-01

The Bull Canyon quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite depots. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tones. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Geology of the Copper King Mine area, Prairie Divide, Larimer County, Colorado (Part 1)

USGS Publications Warehouse

Sims, Paul Kibler; Phair, George

1952-01-01

The Copper King mine, in Larimer County, Colo., in the northern part of the Front Range of Colorado, was operated for a short time prior to World War II for copper and zino, but since 1949, when pitchblende was discovered on the mine dump, it has been worked for uranium. The bedrock in the mine area consists predominantly of pre-Cambrian (Silver Plums) granite with minor migmatite and metasediments--biotite-quartz-plagioclase gneiss, biotite schist, quartzite, amphibolite, amphibole skarn, and biotite skols. The metasediments occur as inclusions that trend northeast in the granite. This trend is essentially parallel to the prevailing foliation in the granite. At places the metasediments are crosscut sharply by the granite to form angular, partly discordant, steep-walled bodies in the granite. Faults, confined to a narrow zone that extends through the mine, cut both the pre-Cambrian rocks and the contained sulfide deposits. The Copper King fault, a breccia zone, contains a deposit of pitchblende; the other faults are believed to be later than the ore. The two types of mineral deposits--massive sulfide and pitchblende deposits--in the mine area, are of widely different mineralogy, age, and origin. The massive sulfide deposits are small and consist of pyrite, sphalerite, chalcopyrite, pyrrhotite, and in places magnetite in amphibole skarn, mice skols, and quartzite. The deposit at the Copper King mine has yielded small quantities of high-grade sphalerite ore. The massive sulfides are pyrometasomatic deposits of pre-Cambrian age. The pitchblende at the Copper King mine is principally in the Copper King vein, a tight, hard breccia zone that cuts through both granite and the massive sulfide deposit. A small part of the pitchblende is in small fractures near the vein and in boxwork pyrite adjacent to the vein; the post-ore faults, close to their intersection with the Copper King vein, contain some radioactive material, but elsewhere, so far as is known, they are barren. The pitchblende in the deposit forms a steeply plunging ore shoot that has a horizontal length of more than 50 feet and a vertical height of about 85 feet. The thickness of the ore shoot averages about 2 feet, but it ranges from a feather edge to about 4 feet. The hard pitch-blende is intimately intergrown with siderite; other gangue minerals include pyrite, quartz, and finely comminuted fragments of the wall rocks. The vein was repeatedly reopened during mineral deposition as shown by several stages of brecciation and recommended by the vein matter. The pitchblende deposit probably formed at intermediate temperatures and depths and, according to the Pb/U ratio, is about 60 million years old--an early Tertiary age.

Preliminary report on the Comet area, Jefferson County, Montana

USGS Publications Warehouse

Becraft, George Earle

1952-01-01

Several radioactivity anomalies and a few specimens of sooty pitchblende and other uranium minerals have been found on the mine dumps of formerly productive base-and precious-metal mines along the Comet-Gray Eagle shear zone in the Comet area in southwestern Montana. The shear zone is from 50 to 200 feet wide and has been traced for at least 5 1/2 miles. It trends N. 80° W. across the northern part of the area and cuts the quartz monzonitic rocks of the Boulder batholith and younger silicic intrusive rocks, as well as the pre-batholitic volcanic rocks, and is in turn cut by dacite and andesite dikes. The youngest period of mineralization is represented by chalcedonic vein zones comprising one or more discontinuous stringers and veins of cryptocrystalline silica in silicified quartz monzonite and in alaskite that has not been appreciably silicified. In some places these zones contain no distinct chalcedonic veins, but are represented only by silicified quartz monzonite. These zones locally contain uranium in association with very small amounts of the following minerals: pyrite, galena, ruby silver, argentite, native silver, molybdenite, chalcopyrite, arsenopyrite, and barite. At the Free Enterprise mine, uranium has been produced from a narrow chalcedonic vein that contains disseminated secondary uranium minerals and local small pods of pitchblende and from disseminated secondary uranium minerals in the adjacent quartz monzonite. Undiscovered commercial deposits of uranium ore may occur spatially associated with the base-and precious-metal deposits along the Comet-Gray Eagle shear zone, and chalcedonic vein zones similar to the Free Enterprise.

A top-down assessment of energy, water and land use in uranium mining, milling, and refining

DOE Office of Scientific and Technical Information (OSTI.GOV)

E. Schneider; B. Carlsen; E. Tavrides

2013-11-01

Land, water and energy use are key measures of the sustainability of uranium production into the future. As the most attractive, accessible deposits are mined out, future discoveries may prove to be significantly, perhaps unsustainably, more intensive consumers of environmental resources. A number of previous attempts have been made to provide empirical relationships connecting these environmental impact metrics to process variables such as stripping ratio and ore grade. These earlier attempts were often constrained by a lack of real world data and perform poorly when compared against data from modern operations. This paper conditions new empirical models of energy, watermore » and land use in uranium mining, milling, and refining on contemporary data reported by operating mines. It shows that, at present, direct energy use from uranium production represents less than 1% of the electrical energy produced by the once-through fuel cycle. Projections of future energy intensity from uranium production are also possible by coupling the empirical models with estimates of uranium crustal abundance, characteristics of new discoveries, and demand. The projections show that even for the most pessimistic of scenarios considered, by 2100, the direct energy use from uranium production represents less than 3% of the electrical energy produced by the contemporary once-through fuel cycle.« less

The Resin-in-pulp Process and Its Application to Ores from Brosses "BRS 10"; LE PROCEDE "RESIN IN PULP" ET SON APPLICATION AUX MINERAIS DES BROSSES "BRS 10"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kremer, M.

1959-03-01

The resin-in-pulp process is a technical variant of the recovery process of uranium in dilute solution by means of ion exchange resins. An anion resin, XE 123, of a welldefined grain size is placed in direct contact with the pulp produced by sulfuric acid attack on ore with a low uranium content. This process is of particular value in the treatment of pulps that cannot be filtered or decanted, such as those obtained with ore from Brosses. The preparation of the pulp, the elution of the uranium, and its fixation, as well as the various factors encountered in these operations,more » are discussed. (auth)« less

Characterization of cores from an in-situ recovery mined uranium deposit in Wyoming: Implications for post-mining restoration

DOE Office of Scientific and Technical Information (OSTI.GOV)

WoldeGabriel, G.; Boukhalfa, H.; Ware, S. D.

In-situ recovery (ISR) of uranium (U) from sandstone-type roll-front deposits is a technology that involves the injection of solutions that consist of ground water fortified with oxygen and carbonate to promote the oxidative dissolution of U, which is pumped to recovery facilities located at the surface that capture the dissolved U and recycle the treated water. The ISR process alters the geochemical conditions in the subsurface creating conditions that are more favorable to the migration of uranium and other metals associated with the uranium deposit. There is a lack of clear understanding of the impact of ISR mining on themore » aquifer and host rocks of the post-mined site and the fate of residual U and other metals within the mined ore zone. We performed detailed petrographic, mineralogical, and geochemical analyses of several samples taken from about 7 m of core of the formerly the ISR-mined Smith Ranch–Highland uranium deposit in Wyoming. We show that previously mined cores contain significant residual uranium (U) present as coatings on pyrite and carbonaceous fragments. Coffinite was identified in three samples. Core samples with higher organic (> 1 wt.%) and clay (> 6–17 wt.%) contents yielded higher 234U/ 238U activity ratios (1.0–1.48) than those with lower organic and clay fractions. The ISR mining was inefficient in mobilizing U from the carbonaceous materials, which retained considerable U concentrations (374–11,534 ppm). This is in contrast with the deeper part of the ore zone, which was highly depleted in U and had very low 234U/ 238U activity ratios. This probably is due to greater contact with the lixiviant (leaching solution) during ISR mining. EXAFS analyses performed on grains with the highest U and Fe concentrations reveal that Fe is present in a reduced form as pyrite and U occurs mostly as U(IV) complexed by organic matter or as U(IV) phases of carbonate complexes. Moreover, U–O distances of ~ 2.05 Å were noted, indicating the potential formation of other poorly defined U(IV/VI) species. We also noted a small contribution from Udouble bond; length as m-dashO at 1.79 Å, which indicates that U is partially oxidized. There is no apparent U–S or U–Fe interaction in any of the U spectra analyzed. However, SEM analysis of thin sections prepared from the same core material reveals surficial U associated with pyrite which is probably a minor fraction of the total U present as thin coatings on the surface of pyrite. Our data show the presence of different structurally variable uranium forms associated with the mined cores. U associated with carbonaceous materials is probably from the original U mobilization that accumulated in the organic matter-rich areas under reducing conditions during shallow burial diagenesis. U associated with pyrite represents a small fraction of the total U and was likely deposited as a result of chemical reduction by pyrite. Our data suggest that areas rich in carbonaceous materials had limited exposure to the lixiviant solution, continue to be reducing, and still hold significant U resources. Because of their limited access to fluid flow, these areas might not contribute significantly to post-mining U release or attenuation. Areas with pyrite that are accessible to fluids seem to be more reactive and could act as reductants and facilitate U reduction and accumulation, limiting its migration.« less

Characterization of cores from an in-situ recovery mined uranium deposit in Wyoming: Implications for post-mining restoration

DOE PAGES

WoldeGabriel, G.; Boukhalfa, H.; Ware, S. D.; ...

2014-10-08

In-situ recovery (ISR) of uranium (U) from sandstone-type roll-front deposits is a technology that involves the injection of solutions that consist of ground water fortified with oxygen and carbonate to promote the oxidative dissolution of U, which is pumped to recovery facilities located at the surface that capture the dissolved U and recycle the treated water. The ISR process alters the geochemical conditions in the subsurface creating conditions that are more favorable to the migration of uranium and other metals associated with the uranium deposit. There is a lack of clear understanding of the impact of ISR mining on themore » aquifer and host rocks of the post-mined site and the fate of residual U and other metals within the mined ore zone. We performed detailed petrographic, mineralogical, and geochemical analyses of several samples taken from about 7 m of core of the formerly the ISR-mined Smith Ranch–Highland uranium deposit in Wyoming. We show that previously mined cores contain significant residual uranium (U) present as coatings on pyrite and carbonaceous fragments. Coffinite was identified in three samples. Core samples with higher organic (> 1 wt.%) and clay (> 6–17 wt.%) contents yielded higher 234U/ 238U activity ratios (1.0–1.48) than those with lower organic and clay fractions. The ISR mining was inefficient in mobilizing U from the carbonaceous materials, which retained considerable U concentrations (374–11,534 ppm). This is in contrast with the deeper part of the ore zone, which was highly depleted in U and had very low 234U/ 238U activity ratios. This probably is due to greater contact with the lixiviant (leaching solution) during ISR mining. EXAFS analyses performed on grains with the highest U and Fe concentrations reveal that Fe is present in a reduced form as pyrite and U occurs mostly as U(IV) complexed by organic matter or as U(IV) phases of carbonate complexes. Moreover, U–O distances of ~ 2.05 Å were noted, indicating the potential formation of other poorly defined U(IV/VI) species. We also noted a small contribution from Udouble bond; length as m-dashO at 1.79 Å, which indicates that U is partially oxidized. There is no apparent U–S or U–Fe interaction in any of the U spectra analyzed. However, SEM analysis of thin sections prepared from the same core material reveals surficial U associated with pyrite which is probably a minor fraction of the total U present as thin coatings on the surface of pyrite. Our data show the presence of different structurally variable uranium forms associated with the mined cores. U associated with carbonaceous materials is probably from the original U mobilization that accumulated in the organic matter-rich areas under reducing conditions during shallow burial diagenesis. U associated with pyrite represents a small fraction of the total U and was likely deposited as a result of chemical reduction by pyrite. Our data suggest that areas rich in carbonaceous materials had limited exposure to the lixiviant solution, continue to be reducing, and still hold significant U resources. Because of their limited access to fluid flow, these areas might not contribute significantly to post-mining U release or attenuation. Areas with pyrite that are accessible to fluids seem to be more reactive and could act as reductants and facilitate U reduction and accumulation, limiting its migration.« less

10 CFR 40.23 - General license for carriers of transient shipments of natural uranium other than in the form of...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false General license for carriers of transient shipments of natural uranium other than in the form of ore or ore residue. 40.23 Section 40.23 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE MATERIAL General Licenses § 40.23 General license for...

Uranium-lead dating of hydrothermal zircon and monazite from the Sin Quyen Fe-Cu-REE-Au-(U) deposit, northwestern Vietnam

NASA Astrophysics Data System (ADS)

Li, Xiao-Chun; Zhou, Mei-Fu; Chen, Wei Terry; Zhao, Xin-Fu; Tran, MyDung

2018-03-01

The Sin Quyen deposit in northwestern Vietnam contains economic concentrations of Cu, Au and LREE, and sub-economic concentration of U. In this deposit, massive and banded replacement ores are hosted in Neoproterozoic metapelite. The paragenetic sequence includes sodic alteration (stage I), calcic-potassic alteration and associated Fe-REE-(U) mineralization (stage II), Cu-Au mineralization (stage III), and sulfide-(quartz-carbonate) veins (stage IV). The Sin Quyen deposit experienced an extensive post-ore metamorphic overprint, which makes it difficult to precisely determine the mineralization age. In this study, zircon and monazite U-Pb geochronometers and the Rb-Sr isochron method are used to constrain the timing of mineralization. Zircon grains in the ore are closely intergrown or texturally associated with hydrothermal minerals of stage II (e.g., garnet, allanite, and hedenbergite). They may contain primary fluid inclusions and display irregular zoning in cathodoluminescence (CL) images. Zircon grains are rich in U (688 to 2902 ppm) and poor in Th (0.2 to 2.9 ppm). Their δ18OV-SMOW values range from 11.9 to 14.0‰, higher than those of typical magmatic zircon. These textural and compositional features imply that zircon precipitated from 18O- and U-rich hydrothermal fluids, coeval with the minerals of stage II. Monazite occurs in close association with stage II magnetite and allanite and has low contents of Th (<2700 ppm), indicative of a hydrothermal origin. Hydrothermal zircon and monazite have indistinguishable U-Pb ages of 841 ± 12 and 836 ± 18 Ma, respectively, representing the timing of Fe-REE mineralization. There is no direct isotopic constraint on the timing of the Cu-Au mineralization, but geological observations suggest that the Cu-Au and Fe-REE ores most likely formed within a single evolved hydrothermal process. In the plot of 87Rb/86Sr vs. 87Sr/86Sr, the composition of bulk-ore and biotite separates from ore lie along a reference line for 30 Ma, which is consistent with the timing of metamorphism in the region. The mineralization age of the Sin Quyen deposit falls within the overall age range (740 to 860 Ma) of the regional Neoproterozoic igneous rocks. This temporal linkage, in combination with the magmatic-like sulfur isotopes of sulfide minerals (δ34SV-CDT = -0.8 to 3.1), indicates that the mineralization may have a close genetic association with the Neoproterozoic igneous activity.

Summary of reconnaissance for radioactive deposits in Alaska, 1945-1954, and an appraisal of Alaskan uranium possibilities

USGS Publications Warehouse

Wedow, Helmuth

1956-01-01

In the period 1945-1954 over 100 investigations for radioactive source materials were made in Alaska. The nature of these investigations ranged from field examinations of individual prospects or the laboratory analysis of significantly radioactive samples submitted by prospectors to reconnaissance studies of large districts. In this period no deposits of uranium or thorium that would warrant commercial exploitation were discovered. The investigations, however, disclosed that radioactive materials occur in widely scattered areas of Alaska and in widely diverse environments. Many igneous rocks throughout Alaska are weakly radioactive because of uranium- and thorium-bearing accessory minerals, such as allanite, apatite, monazite, sphene, xenotime, and zircon; more rarely the radioactivity of these rocks is due to thorianite or thorite and their uranoan varieties. The felsic rocks, for example, granites and syenites, are generally more radioactive than the mafic igneous rocks. Pegmatites, locally, have also proved to be radioactive, but they have little commercial significance. No primary uranium oxide minerals have been found yet in Alaskan vein deposits, except, perhaps, for a mineral tentatively identified as pitchblende in the Hyder district of southeastern Alaska. However, certain occurrences of secondary uranium minerals, chiefly those of the uranite group, on the Seward Peninsula, in the Russian Mountains, and in the vicinity of Kodiak suggest that pitchblende-type ores may occur at depth beneath zones of alteration. Thorite-bearing veins have been discovered on Prince of Wales Island in southeastern Alaska. Although no deposits or carnotite-type minerals have been found in Alaska, several samples containing such minerals have been submitted by Alaskan prospectors. Efforts to locate the deposits from which these minerals were obtained have been unsuccessful, but review of available geologic data suggests that several Alaskan areas are potentially favorable for carnotite-type deposits. The chief of these areas is the Alaska Peninsula-Cook Inlet area which encompasses most of the reported occurrences of the prospectors' carnotite-type samples. Alaska is also potentially favorable for the occurrence of large bodies of the very low-grade uraniferous sedimentary rocks, such as phosphorites and black shales. This type of deposit, however, has not received much study because of the emphasis on the search for bonanza-type high-grade ores. Uraniferous phosphorites similar to those of Idaho, Montana, and Wyoming occur in northern Alaska on the north flank of the Brooks Range; black shales comparable to the uraniferous shales of the Chattanooga formation of southeastern United States have been noted along the Yukon River near the international boundary. Placer deposits in Alaska have some small potential for the production of the radioactive elements as byproducts of gold- and tin-placer mining. the placer area believed to have the relatively greatest potential in Alaska lies in the Kahiltna River valley where concentrates are known to contain such commercial minerals as ilmenite, cassiterite, platinum, and gold in addition to uranothorianite and monazite. The possibilities of the natural fluids--water and petroleum--have not yet been tested in Alaska to any great extent. Studies of fluids are in progress to determine whether they may be used to discover and define areas potentially favorable for the occurrence of uraniferous lodes.

Hydrocarbon-mediated gold and uranium concentration in the Witwatersrand Basin, South Africa

NASA Astrophysics Data System (ADS)

Fuchs, Sebastian; Williams-Jones, Anthony; Schumann, Dirk; Couillard, Martin; Murray, Andrew

2016-04-01

The Witwatersrand deposits in South Africa represent the largest repository of gold in the World and a major resource of uranium. The genesis of the gold and uranium ores in the quartz-pebble conglomerates (reefs), however, is still a matter of considerable discussion. Opinion has been divided over whether they represent paleo-placers that have been partly remobilised by hydrothermal fluids or if the mineralisation is entirely hydrothermal in origin. In addition, recently published models have proposed a syngenetic origin for the gold involving bacterially-mediated precipitation from meteoric water and shallow seawater. An important feature of the gold and uranium mineralisation in the reefs is the strong spatial association with organic matter. In some reefs, up to 70% of the gold and almost the entire uranium resource is spatially associated with pyrobitumen seams, suggesting a genetic relationship of the gold-uranium mineralisation with hydrocarbons. Here we report results of a study of the Carbon Leader Reef, using high-resolution scanning and transmission electron microscopy (SEM / TEM) and LA-ICP-MS that provide new insights into the role of hydrocarbons in the concentration of the gold and uranium. A detailed examination revealed gold monocrystals containing numerous rounded or elliptical inclusions filled with pyrobitumen. We interpret these inclusions to record the crystallisation of the gold around droplets of a hydrocarbon liquid that migrated through the Witwatersrand basin, and was converted to pyrobitumen by being heated. We propose that the gold was transported in a hydrothermal fluid as a bisulphide complex and that this fluid mixed with the hydrocarbon liquid to form a water-oil emulsion. The interaction between the two fluids caused a sharp reduction in fO2 at the water-oil interface, which destabilised the gold-bisulphide complexes, causing gold monocrystals to precipitate around the oil droplets. In contrast to the gold, uraninite, the principal uranium mineral, occurs as complex-shaped grains that represent aggregates containing billions of uraninite nanocrystals (5 - 7 nm in diameter), which grew in situ in the pyrobitumen matrix or more likely its liquid precursor (Fuchs et al., 2015). This in situ growth of isolated nanocrystalline aggregates shows that uranium was mobilised and concentrated by liquid hydrocarbons, and that uraninite nanocrystals were released from the oils during the conversion of oil to pyrobitumen. Our study provides new insights into the complex mechanisms of ore formation in the Witwatersrand Supergroup and compelling evidence that hydrocarbons played a major role in the concentration of the gold and uranium. It does not rule out the possibility that gold and uranium were introduced into the Witwatersrand Basin as detrital grains but shows that mobilisation of gold and uranium by hydrothermal fluids and hydrocarbon liquids, respectively, and the mixing of these fluids, were essential to ore formation. Fuchs, S., Schumann, D., Williams-Jones, A.E., Vali, H., 2015. The growth and concentration of uranium and titanium minerals in hydrocarbons of the Carbon Leader Reef, Witwatersrand Supergroup, South Africa. Chemical Geology 393-394, 55-66.

Thorium Energy Resources and its Potential of Georgian Republic, The Caucasus

NASA Astrophysics Data System (ADS)

Gogoladze, Salome; Okrostsvaridze, Avtandil

2017-04-01

Energy resources, currently consumed by modern civilization, are represented by hydrocarbons - 78-80 %, however these reserves are exhausting. In light of these challenges, search of new energy resources is vital importance problem for the modern civilization. Based on the analysis of existing energy reserves and potential, as the main energy resources for the future of our civilization, the renewable and nuclear energy should be considered. However, thorium has a number of advantages compared to Uranium (Kazimi, 2003; et al.): It is concentrated in the earth crust 4-5 times more than uranium; extraction and enrichment of thorium is much cheaper than uranium's; It is less radioactive; complete destruction of its waste products is possible; thorium yields much more energy than uranium. Because of unique properties and currently existed difficult energetic situation thorium is considered as the main green energy resource in the 3rd millennium of the human civilization (Martin, 2009). Georgia republic, which is situated in the central part of Caucasus, poor of hydrocarbons, but has a thorium resource important potential. In general the Caucasus represents a collisional orogen, that formed along the Eurasian North continental margin and extends over 1200 km from Caspian to Black Sea. Three major units are distinguished in its construction: the Greater and Lesser Caucasian mobile belts and the Transcaucasus microplate. Currently it represents the Tethyan segment connecting the Mediterranean and Iran-Himalayan orogenic belts, between the Gondvana-derived Arabian plate and East European platform. Now in Georgian Republic are marked thorium four ore occurrences (Okrostsvaridze, 2014): 1- in the Sothern slope of the Greater Caucasus, in the quartz -plagioclases veins (Th concentrations vary between 51g/t - 3882 g/t); 2- in the Transcaucasus Dzirula massif hydrothermally altered rocks of the Precambrian quartz-diorite gneisses (Th concentrations vary between 117 g/t -266 g/t); 3- in magnetite ore bodies of Vakijvari ore field (Th concentrations vary between 185 g/t - 1600 g/t); 4- in the black sand (magnetite sand) of the Black Sea Guria region coast (Th concentrations vary between 200 g/t - 450 g/t). Based on these data and on the correlation of these information on the other thorium deposit of the world, the Georgian thorium ore occurrences should be treated as a prospective objects. Because of this, we consider that complex investigation of thorium resources of Georgia should be included into the sphere of strategic interests of the state. REFERENCES Martin R., 2009. "Uranium is So Last Centure - Enter Thorium , the New Green Nuke", Weird Magazine, Dec. 21. Kazimi M. S., 2003. "Thorium fuel for nuclear energy", American Scientist, 91, pp. 305-313. Okrostsvaridze A. V., 2014. Torium - Future Energy of Modern Civilization? and its Ore Occurrences in Georgia Republic. Bull.Georg. Natl. Acad. Sci., vol. 8., no 3, pp. 48-55.

Characterization of uranium bearing material using x-ray fluorescence and direct gamma-rays measurement techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mujaini, M., E-mail: madihah@uniten.edu.my; Chankow, N.; Yusoff, M. Z.

2016-01-22

Uranium ore can be easily detected due to various gamma-ray energies emitted from uranium daughters particularly from {sup 238}U daughters such as {sup 214}Bi, {sup 214}Pb and {sup 226}Ra. After uranium is extracted from uranium ore, only low energy gamma-rays emitted from {sup 235}U may be detected if the detector is placed in close contact to the specimen. In this research, identification and characterization of uranium bearing materials is experimentally investigated using direct measurement of gamma-rays from {sup 235}U in combination with the x-ray fluorescence (XRF) technique. Measurement of gamma-rays can be conducted by using high purity germanium (HPGe) detectormore » or cadmium telluride (CdTe) detector while a {sup 57}Coradioisotope-excited XRF spectrometer using CdTe detector is used for elemental analysis. The proposed technique was tested with various uranium bearing specimens containing natural, depleted and enriched uranium in both metallic and powder forms.« less

Geology and uranium deposits of the Cochetopa and Marshall Pass districts, Saguache and Gunnison counties, Colorado

USGS Publications Warehouse

Olson, Jerry C.

1988-01-01

The Cochetopa and Marshall Pass uranium districts are in Saguache and Gunnison Counties, south-central Colorado. Geologic mapping of both districts has shown that their structural history and geologic relationships have a bearing on the distribution and origin of their uranium deposits. In both districts, the principal uranium deposits are situated at the intersection of major faults with Tertiary erosion surfaces. These surfaces were buried by early Tertiary siliceous tuffs-- a likely source of the uranium. That uranium deposits are related to such unconformities in various parts of the world has been suggested by many other authors. The purpose of this study is to understand the geology of the two districts and to define a genetic model for uranium deposits that may be useful in the discovery and evaluation of uranium deposits in these and other similar geologic settings. The Cochetopa and Marshall Pass uranium districts produced nearly 1,200 metric tons of uranium oxide from 1956 to 1963. Several workings at the Los Ochos mine in the Cochetopa district, and the Pitch mine in the Marshall Pass district, accounted for about 97 percent of this production, but numerous other occurrences of uranium are known in the two districts. As a result of exploration of the Pitch deposit in the 1970's, a large open-pit mining operation began in 1978. Proterozoic rocks in both districts comprise metavolcanic, metasedimentary, and igneous units. Granitic rocks, predominantly quartz monzonitic in composition, occupy large areas. In the northwestern part of the Cochetopa district, metavolcanic and related metasedimentary rocks are of low grade (lower amphibolite facies). In the Marshall Pass district, layered metamorphic rocks are predominantly metasedimentary and are of higher (sillimanite subfacies) grade than the Cochetopa rocks. Paleozoic sedimentary rocks in the Marshall Pass district range from Late Cambrian to Pennsylvanian in age and are 700 m thick. The Paleozoic rocks include, from oldest to youngest, the Sawatch Quartzite, Manitou Dolomite, Harding Quartzite, Fremont Dolomite, Parting Formation and Dyer Dolomite of the Chaffee Group, Leadville Dolomite, and Belden Formation. In the Cochetopa district, Paleozoic rocks are absent. Mesozoic sedimentary rocks overlie the Precambrian rocks in the Cochetopa district and comprise the Junction Creek Sandstone, Morrison Formation, Dakota Sandstone, and Mancos Shale. In the Marshall Pass district, Mesozoic rocks are absent and were presumably removed by pre-Tertiary erosion. Tertiary volcanic rocks were deposited on an irregular surface of unconformity; they blanketed both districts but have been eroded, away from much of the area. They include silicic ash flows as well as andesitic lava flows and breccias. In the Marshall Pass district, a 20to 20D-m thickness of waterlaid tuff of early Tertiary age indicates the former presence of a lake over much of the district. In the Cochetopa district, faults have a predominantly east-west trend, and the major Los Ochos fault shows displacement during Laramide time. In the Marshall Pass district, the Chester fault is a major north-trending reverse fault along which Proterozoic rocks have been thrust westward over Paleozoic and Proterozoic rocks. Displacement on the Chester fault was almost entirely of Laramide age. Both faults and old erosion surfaces or unconformities are important in the origin of uranium deposits because of their influence on the movement and localization of ore-forming solutions. In the Cochetopa district, all the known uranium occurrences crop out within 100 m of the inferred position of the unconformity surface beneath the Tertiary volcanic rocks. Much of the district was part of the drainage of an ancestral Cochetopa Creek. The principal uranium deposit, at the Los Ochos mine, is localized along the Los Ochos fault and is near the bottom of the paleovalley where the paleovalley crosses the fault. This

Method and apparatus for drilling horizontal holes in geological structures from a vertical bore

DOEpatents

Summers, David A.; Barker, Clark R.; Keith, H. Dean

1982-01-01

This invention is directed to a method and apparatus for drilling horizontal holes in geological strata from a vertical position. The geological structures intended to be penetrated in this fashion are coal seams, as for in situ gasification or methane drainage, or in oil-bearing strata for increasing the flow rate from a pre-existing well. Other possible uses for this device might be for use in the leaching of uranium ore from underground deposits or for introducing horizontal channels for water and steam injections.

Methods Applied to Uranium and Thorium Ore Prospecting. a. In the Desert Countries. b. In the Equatorial Forest Regions of the Union Francaise; LA PROSPECTION DES MINERAIS D'URANIUM ET DE THORIUM DANS LES PAYS DESERTIQUES ET DANS LES REGIONS DE FORET EQUATORIALE DE L'UNION FRANCAISE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lecoq, J.J.; Bigotte, G.; Hinault, J.

1959-10-31

Since 1946 the Commissariat a l'Energie Atomique has supported explorations for uranium and thorium deposits in the French territorial possessions of French territorial possessions of French Africa, Madagascar, and French Guiana. A lange part of this territory is desert, equatorial forest, or savannah regions. The particular difficulties of prospecting for radioactive minerals in these territories include the geographic character of the region, the climate, and the lack of access and skilled labor. The different methods of prospecting in the desert and equatorial forests include photogeology, aerial and ground prospecting, geochemical and geophysical techniques, and the training of local labor formore » prospecting. These techniques are described, and the results obtained are discussed. Three examples of prospecting in countries with extreme climates are given. (J.S.R.)« less

Egypt/United States cooperative energy assessment. Volume II, Annex 1. Energy resources of Egypt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-04-01

This report contains the findings and recommendations of the US Geological Survey geologists assigned to survey Egypts indigenous energy resources. Data on oil and gas, coal and oil shale, uranium and thorium, geothermal energy, water resources, and energy related minerals are presented. Thirty-nine oil and gas fields have been discovered in Egypt, proven reserves of oil were estimated to be 1,559,000,000 barrels in 1976. The Egyptian government hopes to attain a production rate of 1 million barrels a day in 1982. While the Gulf of Suez basin holds the most immediate prospects, the most promising frontier regions are the unexploredmore » broad expanses of the Western Desert, the Nile Basin and the Northern Sinai while oil shales have been found in Egypt, they are only 10 to 15 feet thick and their hydrocarbon content is low. Recovery would not be economic. Coal deposits contain reserves estimated at 95 to 112 million tons. Only 1 deposit is deemed workable under present conditions of technology and economy. No uranium and thorium are being produced however geological conditions appear favorable for finding uranium deposits using appropriate programs of prospecting, exploration and development. The potential for development of low-level sources of geothermal energy in Egypt is good; there is no evidence of a high-temperature source or a vapor-dominated system. The Nile is the primary source of water. In the western desert, the Nubian aquifer supplies water for irrigation. Energy related minerals are generally found in uneconomic concentrations or not at all. However, deposits of material used in cement making and some iron ore for steel making are available. Deposits of manganese may become available upon return of the Sinai to Egypt. 44 figures, 24 tables. (DMC)« less

U.S.-Australia Civilian Nuclear Cooperation: Issues for Congress

DTIC Science & Technology

2010-09-30

7 Uranium Mining and Milling ................................................................................................8...cycle begins with mining uranium ore and upgrading it to yellowcake. Because naturally occurring uranium lacks sufficient fissile 235U to make fuel for...enrichment, and finally fabrication into fuel elements. Australia exports its uranium after the mining and milling stage. Commercial enrichment services

Uranium (U)-Tolerant Bacterial Diversity from U Ore Deposit of Domiasiat in North-East India and Its Prospective Utilisation in Bioremediation

PubMed Central

Kumar, Rakshak; Nongkhlaw, Macmillan; Acharya, Celin; Joshi, Santa Ram

2013-01-01

Uranium (U)-tolerant aerobic chemo-heterotrophic bacteria were isolated from the sub-surface soils of U-rich deposits in Domiasiat, North East India. The bacterial community explored at molecular level by amplified ribosomal DNA restriction analysis (ARDRA) resulted in 51 distinct phylotypes. Bacterial community assemblages at the U mining site with the concentration of U ranging from 20 to 100 ppm, were found to be most diverse. Representative bacteria analysed by 16S rRNA gene sequencing were affiliated to Firmicutes (51%), Gammaproteobacteria (26%), Actinobacteria (11%), Bacteroidetes (10%) and Betaproteobacteria (2%). Representative strains removed more than 90% and 53% of U from 100 μM and 2 mM uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure and the activity was retained until 24 h. Overall, 76% of characterized isolates possessed phosphatase enzyme and 53% had PIB-type ATPase genes. This study generated baseline information on the diverse indigenous U-tolerant bacteria which could serve as an indicator to estimate the environmental impact expected to be caused by mining in the future. Also, these natural isolates efficient in uranium binding and harbouring phosphatase enzyme and metal-transporting genes could possibly play a vital role in the bioremediation of metal-/radionuclide-contaminated environments. PMID:23080407

Uranium and organic matters: use of pyrolysis-gas chromatography, carbon, hydrogen, and uranium contents to characterize the organic matter from sandstone-type deposits

USGS Publications Warehouse

Leventhal, Joel S.

1979-01-01

Organic matter seems to play an important role in the genesis of uranium deposits in sandstones in the western United States. Organic materials associated with ore from the Texas coastal plain, Tertiary basins of Wyoming, Grants mineral belt of New Mexico, and the Uravan mineral belt of Utah and Colorado vary widely in physical appearance and chemical composition. Partial characterization of organic materials is achieved by chemical analyses to determine atomic hydrogen-to-carbon (H/C) ratios and by gas chromatographic analyses to determine the molecular fragments evolved during stepwise pyrolysis. From the pyrolysis experiments the organic materials can be classified and grouped: (a) lignites from Texas and Wyoming and (b) hydrogen poor materials, from Grants and Uravan mineral belts and Wyoming; (c) naphthalene-containing materials from Grants mineral belt and Wyoming; and (d) complex and aromatic materials from Uravan, Grants and Wyoming. The organic materials analyzed have atomic H/C ratios that range from approximately 0.3 to at least 1.5. The samples with higher H/C ratios yield pyrolysis products that contain as many as 30 carbon atoms per molecule. Samples with low H/C ratios are commonly more uraniferous and yield mostly methane and low-molecular-weight gases during pyrolysis.

Federal Guidance Report No. 8: Guidance for the Control of Radiation Hazards in Uranium Mining

EPA Pesticide Factsheets

This report contains background material used in the development of guidance concerning radiation protection in the mining of uranium ore, and seeks to provide guidance for long-term radiation protection in uranium mining.

Mines and Prospects, Idaho Springs District, Clear Creek and Gilpin Counties, Colorado - Descriptions and Maps

USGS Publications Warehouse

Moench, Robert Hadley; Drake, Avery Ala

1966-01-01

The Idaho Springs mining district forms an important segment of the Front Range mineral belt, a northeast-trending zone of coextensive intrusive rocks and hydrothermal ore deposits of early Tertiary age. This belt, which is about 50 miles long, extends from the region just west of Boulder southwestward across the Front Range. From 1859, when placer gold was discovered in Idaho Springs and lode gold in Central City, through 1959, ores valued at about $200 million were shipped from a 50-square-mile area that includes the Idaho Springs and adjacent districts to the north, west, and southwest. The adjacent Central City district, which produced ores valued at more than $100 million, is clearly the most important district in the mineral belt. The Idaho Springs district from 1860 to 1959 produced ores valued at about $65 million, and the districts to the west and southwest produced smaller amounts. Gold has accounted for about 60 percent of the value of the ore, but in some areas silver provides the chief values, and copper, lead, and zinc add value to the ores in most areas. Mining activity in the Idaho Springs and adjacent districts was at its 'heyday' in the late 1800's, it declined sharply after 1914, it was somewhat renewed during the 1930's, and it greatly declined during World War II. In the 1950's uranium prospecting stimulated some mining activity. No uranium was produced, however, and at the close of the decade only one mine--the Bald Eagle--was being worked for its precious- and base-metal ores. In this report, 135 mines and prospects are described. The mines and prospects described are those that were accessible at the time of this study, as well as a few inaccessible properties for which some information was available. Most of the data for the inaccessible or unimportant properties were obtained from Bastin and Hill (1917) and Spurr, Garrey, and Ball (1908). The following list shows, in alphabetical order, the names of about 325 openings of mines and prospects, their coordinate location on the district map (fig. 1), the page of this report on which their description starts, and the number of the illustration, if any, referring to them.

DISSOLUTION AND ANALYSIS OF YELLOWCAKE COMPONENTS FOR FINGERPRINTING UOC SOURCES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hexel, Cole R; Bostick, Debra A; Kennedy, Angel K

2012-01-01

There are a number of chemical and physical parameters that might be used to help elucidate the ore body from which uranium ore concentrate (UOC) was derived. It is the variation in the concentration and isotopic composition of these components that can provide information as to the identity of the ore body from which the UOC was mined and the type of subsequent processing that has been undertaken. Oak Ridge National Laboratory (ORNL) in collaboration with Lawrence Livermore and Los Alamos National Laboratories is surveying ore characteristics of yellowcake samples from known geologic origin. The data sets are being incorporatedmore » into a national database to help in sourcing interdicted material, as well as aid in safeguards and nonproliferation activities. Geologic age and attributes from chemical processing are site-specific. Isotopic abundances of lead, neodymium, and strontium provide insight into the provenance of geologic location of ore material. Variations in lead isotopes are due to the radioactive decay of uranium in the ore. Likewise, neodymium isotopic abundances are skewed due to the radiogenic decay of samarium. Rubidium decay similarly alters the isotopic signature of strontium isotopic composition in ores. This paper will discuss the chemical processing of yellowcake performed at ORNL. Variations in lead, neodymium, and strontium isotopic abundances are being analyzed in UOC from two geologic sources. Chemical separation and instrumental protocols will be summarized. The data will be correlated with chemical signatures (such as elemental composition, uranium, carbon, and nitrogen isotopic content) to demonstrate the utility of principal component and cluster analyses to aid in the determination of UOC provenance.« less

Video processing of remote sensor data applied to uranium exploration in Wyoming. [Roll-front U deposits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levinson, R.A.; Marrs, R.W.; Crockell, F.

1979-06-30

LANDSAT satellite imagery and aerial photography can be used to map areas of altered sandstone associated with roll-front uranium deposits. Image data must be enhanced so that alteration spectral contrasts can be seen, and video image processing is a fast, low-cost, and efficient tool. For LANDSAT data, the 7/4 ratio produces the best enhancement of altered sandstone. The 6/4 ratio is most effective for color infrared aerial photography. Geochemical and mineralogical associations occur in unaltered, altered, and ore roll-front zones. Samples from Pumpkin Buttes show that iron is the primary coloring agent which makes alteration visually detectable. Eh and pHmore » changes associated with passage of a roll front cause oxidation of magnetite and pyrite to hematite, goethite, and limonite in the host sandstone, thereby producing the alteration. Statistical analysis show that the detectability of geochemical and color zonation in host sands is weakened by soil-forming processes. Alteration can only be mapped in areas of thin soil cover and moderate to sparse vegetative cover.« less

26 CFR 1.993-3 - Definition of export property.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Application of 50 percent test. The 50 percent test described in subparagraph (1) of this paragraph is applied... uranium concentrates (known in the industry as “yellow cake”), and nuclear fuel materials derived from the refining of uranium ore and uranium concentrates, or produced in a nuclear reaction, including— (a) Uranium...

26 CFR 1.993-3 - Definition of export property.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) Application of 50 percent test. The 50 percent test described in subparagraph (1) of this paragraph is applied... uranium concentrates (known in the industry as “yellow cake”), and nuclear fuel materials derived from the refining of uranium ore and uranium concentrates, or produced in a nuclear reaction, including— (a) Uranium...

Depleted Uranium | RadTown USA | US EPA

EPA Pesticide Factsheets

2018-01-12

Depleted uranium is the material left after most of the highly radioactive uranium-235 is removed from uranium ore for nuclear power and weapons. DU is used for tank armor, armor-piercing bullets and as weights to help balance aircraft. DU is both a toxic chemical and radiation health hazard when inside the body.

Illicit Trafficking of Natural Radionuclides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedrich, Steinhaeusler; Lyudmila, Zaitseva

2008-08-07

Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (<20% U 235) or highly enriched uranium (>20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from anmore » operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.« less

Illicit Trafficking of Natural Radionuclides

NASA Astrophysics Data System (ADS)

Friedrich, Steinhäusler; Lyudmila, Zaitseva

2008-08-01

Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (<20% U 235) or highly enriched uranium (>20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

Biogeochemical aspects of uranium mineralization, mining, milling, and remediation

USGS Publications Warehouse

Campbell, Kate M.; Gallegos, Tanya J.; Landa, Edward R.

2015-01-01

Natural uranium (U) occurs as a mixture of three radioactive isotopes: 238U, 235U, and 234U. Only 235U is fissionable and makes up about 0.7% of natural U, while 238U is overwhelmingly the most abundant at greater than 99% of the total mass of U. Prior to the 1940s, U was predominantly used as a coloring agent, and U-bearing ores were mined mainly for their radium (Ra) and/or vanadium (V) content; the bulk of the U was discarded with the tailings (Finch et al., 1972). Once nuclear fission was discovered, the economic importance of U increased greatly. The mining and milling of U-bearing ores is the first step in the nuclear fuel cycle, and the contact of residual waste with natural water is a potential source of contamination of U and associated elements to the environment. Uranium is mined by three basic methods: surface (open pit), underground, and solution mining (in situ leaching or in situ recovery), depending on the deposit grade, size, location, geology and economic considerations (Abdelouas, 2006). Solid wastes at U mill tailings (UMT) sites can include both standard tailings (i.e., leached ore rock residues) and solids generated on site by waste treatment processes. The latter can include sludge or “mud” from neutralization of acidic mine/mill effluents, containing Fe and a range of coprecipitated constituents, or barium sulfate precipitates that selectively remove Ra (e.g., Carvalho et al., 2007). In this chapter, we review the hydrometallurgical processes by which U is extracted from ore, the biogeochemical processes that can affect the fate and transport of U and associated elements in the environment, and possible remediation strategies for site closure and aquifer restoration.This paper represents the fourth in a series of review papers from the U.S. Geological Survey (USGS) on geochemical aspects of UMT management that span more than three decades. The first paper (Landa, 1980) in this series is a primer on the nature of tailings and radionuclide mobilization from them. The second paper (Landa, 1999) includes coverage of research carried out under the U.S. Department of Energy’s Uranium Mill Tailings Remedial Action Program (UMTRA). The third paper (Landa, 2004) reflects the increased focus of researchers on biotic effects in UMT environs. This paper expands the focus to U mining, milling, and remedial actions, and includes extensive coverage of the increasingly important alkaline in situ recovery and groundwater restoration.

An Overview of Process Monitoring Related to the Production of Uranium Ore Concentrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGinnis, Brent

2014-04-01

Uranium ore concentrate (UOC) in various chemical forms, is a high-value commodity in the commercial nuclear market, is a potential target for illicit acquisition, by both State and non-State actors. With the global expansion of uranium production capacity, control of UOC is emerging as a potentially weak link in the nuclear supply chain. Its protection, control and management thus pose a key challenge for the international community, including States, regulatory authorities and industry. This report evaluates current process monitoring practice and makes recommendations for utilization of existing or new techniques for managing the inventory and tracking this material.

Maps showing mineral resource assessment for vein and replacement deposits of base and precious metals, barite, and fluorspar, Dillon 1 degree by 2 degrees Quadrangle, Idaho and Montana

USGS Publications Warehouse

Pearson, R.C.; Trautwein, C.M.; Berger, B.R.; Hanna, W.F.; Jenson, S.K.; Loen, J.S.; Moll, S.H.; Purdy, T.L.; Rowan, L.C.; Ruppel, E.T.; Segal, D.B.

1992-01-01

This report is one of several that assess the mineral resources in the Dillon quadrangle. For the purpose of the assessment, the deposits that are known in the quadrangle, or suspected to be present from a knowledge of the geologic setting, have been grouped into 30 deposit types on the basis of the mineralogy or commodity in the ore and the structural or depositional setting of the deposit. The emphasis in these assessment reports is on metallic minerals, but some important nonmetallic minerals are also considered. Fossil fuels are beyond the scope of this investigation, phosphate and uranium have been investigated previously (Swanson, 1970; Wodzicki and Krason, 1981 ), and certain nonmetallic minerals, including bulk commodities such as sand and gravel, are in large supply and thus are not considered. The mineral resource assessment discussed in this report concentrates on a single deposit type (of the total of 30 types) that we call "vein and replacement deposits of base and precious metals." Base and precious metals produced from such deposits are copper, lead, zinc, gold, and silver. Vein deposits of barite and fluorspar are also discussed, but because they seem to be of minor importance, they are treated briefly. Vein and replacement deposits of base and precious metals are classified as a single deposit type rather than as numerous possible subordinate types that might be distinguished on the basis of mineralogy, metal content, or other factors, because the characteristics of the ore, the ore bodies, and the structural setting are not sufficiently well known to yield a consistent detailed classification for the entire quadrangle. Furthermore, the criteria used here to explain the localization of deposits are too general to allow discrimination among subordinate types at a scale of 1 :250,000 or smaller. In assessing mineral resources, we have adopted a general philosophy similar to that of Harrison and others ( 1986). We attempt to identify parts of the quadrangle that are favorable for the occurrence of mineral resources, and we make an assignment of the relative resource potential of all parts of the quadrangle. We do not attempt to locate specific exploration targets nor to determine the quantity of reserves or resources present.

Origin of coffinite in sedimentary rocks by a sequential adsorption-reduction mechanism.

USGS Publications Warehouse

Goldhaber, M.B.; Hemingway, B.S.; Mohagheghi, A.; Reynolds, R.L.; Northrop, H.R.

1987-01-01

Coffinite is the dominant ore mineral in the V-U ores of the Tony-M mine in the Henry Mts mineral belt of the Colorado Plateau. This orebody was formed at a density-stratified solution interface between uranyl-ion-bearing meteoric water and a saline fluid which was locally reducing. The localization of U at this solution interface occurred by adsorption onto the surfaces of detrital minerals, this adsorption being related to the pH difference between the two fluids. Experimental evidence is presented showing that the adsorption facilitated the reduction of uranium to U(IV). This adsorbed, reduced uranium bonded with aqueous silica in the ore zone to form coffinite. The high concentration of silica (as a monomeric species) in the ore-forming solution stabilized coffinite in preference to uraninite.-R.A.H.

Uraniferous opal, Virgin Valley, Nevada: conditions of formation and implications for uranium exploration

USGS Publications Warehouse

Zielinski, R.A.

1982-01-01

Uraniferous, fluorescent opal, which occurs in tuffaceous sedimentary rocks at Virgin Valley, Nevada, records the temperature and composition of uranium-rich solutions as well as the time of uranium-silica coprecipitation. Results are integrated with previous geologic and geochronologic data for the area to produce a model for uranium mobility that may be used to explore for uranium deposits in similar geologic settings. Uraniferous opal occurs as replacements of diatomite, or silicic air-fall ash layers in tuffaceous lakebeds of the Virgin Valley Formation (Miocene) of Merriam (1907). Fission-track radiography shows uranium to be homogeneously dispersed throughout the opal structure, suggesting coprecipitation of dissolved uranium and silica gel. Fluid inclusions preserved within opal replacements of diatomite have homogenization temperatures in the epithermal range and are of low salinity. Four samples of opal from one locality all have U-Pb apparent ages which suggest uraniferous opal precipitation in late Pliocene time. These ages correspond to a period of local, normal faulting, and highangle faults may have served as vertical conduits for transport of deep, thermalized ground water to shallower levels. Lateral migration of rising solutions occurred at intersections of faults with permeable strata. Silica and some uranium were dissolved from silica-rich host strata of 5-20 ppm original uranium content and reprecipitated as the solutions cooled. The model predicts that in similar geologic settings, ore-grade concentrations of uranium will occur in permeable strata that intersect high-angle faults and that contain uranium source rocks as well as efficient reductant traps for uranium. In the absence of sufficient quantities of reductant materials, uranium will be flushed from the system or will accumulate in low-grade disseminated hosts such as uraniferous opal. ?? 1982.

PREPARATION OF URANIUM HEXAFLUORIDE

DOEpatents

Lawroski, S.; Jonke, A.A.; Steunenberg, R.K.

1959-10-01

A process is described for preparing uranium hexafluoride from carbonate- leach uranium ore concentrate. The briquetted, crushed, and screened concentrate is reacted with hydrogen fluoride in a fluidized bed, and the uranium tetrafluoride formed is mixed with a solid diluent, such as calcium fluoride. This mixture is fluorinated with fluorine and an inert diluent gas, also in a fluidized bed, and the uranium hexafluoride obtained is finally purified by fractional distillation.

Evolution of ore deposits on terrestrial planets

NASA Astrophysics Data System (ADS)

Burns, R. G.

Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars, but not submarine ferromanganese nodules and crusts which have precipitated in oxygenated seawater on earth.

Evolution of ore deposits on terrestrial planets

NASA Technical Reports Server (NTRS)

Burns, R. G.

1991-01-01

Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars, but not submarine ferromanganese nodules and crusts which have precipitated in oxygenated seawater on earth.

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Requirements for advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE... natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore or...

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Requirements for advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE... natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore or...

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Requirements for advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE... natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore or...

PROCESS FOR UTILIZING ORGANIC ORTHOPHOSPHATE EXTRACTANTS

DOEpatents

Grinstead, R.R.

1958-11-11

A process is presented for recovering uranium from its ores, the steps comprising producing the uranium in solution in the trivalent state, extracting the uranium from solution in an lmmiscible organic solvent extract phase which lncludes mono and dialkyl orthophosphorlc acid esters having a varying number of carbon atoms on the alkyl substituent, amd recovering the uranium from tbe extract phase.

10 CFR 40.66 - Requirements for advance notice of export shipments of natural uranium.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Requirements for advance notice of export shipments of natural uranium. 40.66 Section 40.66 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE... natural uranium. (a) Each licensee authorized to export natural uranium, other than in the form of ore or...

Source identification of uranium-containing materials at mine legacy sites in Portugal.

PubMed

Keatley, A C; Martin, P G; Hallam, K R; Payton, O D; Awbery, R; Carvalho, F P; Oliveira, J M; Silva, L; Malta, M; Scott, T B

2018-03-01

Whilst prior nuclear forensic studies have focused on identifying signatures to distinguish between different uranium deposit types, this paper focuses on providing a scientific basis for source identification of materials from different uranium mine sites within a single region, which can then be potentially used within nuclear forensics. A number of different tools, including gamma spectrometry, alpha spectrometry, mineralogy and major and minor elemental analysis, have been utilised to determine the provenance of uranium mineral samples collected at eight mine sites, located within three different uranium provinces, in Portugal. A radiation survey was initially conducted by foot and/or unmanned aerial vehicle at each site to assist sample collection. The results from each mine site were then compared to determine if individual mine sites could be distinguished based on characteristic elemental and isotopic signatures. Gamma and alpha spectrometry were used to differentiate between samples from different sites and also give an indication of past milling and mining activities. Ore samples from the different mine sites were found to be very similar in terms of gangue and uranium mineralogy. However, rarer minerals or specific impurity elements, such as calcium and copper, did permit some separation of the sites examined. In addition, classification rates using linear discriminant analysis were comparable to those in the literature. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Aftermath of Uranium Ore Processing on Floodplains: Lasting Effects of Uranium on Soil and Microbes

NASA Astrophysics Data System (ADS)

Tang, H.; Boye, K.; Bargar, J.; Fendorf, S. E.

2016-12-01

A former uranium ore processing site located between the Wind River and the Little Wind River near the city of Riverton, Wyoming, has generated a uranium plume in the groundwater within the floodplain. Uranium is toxic and poses a threat to human health. Thus, controlling and containing the spread of uranium will benefit the human population. The primary source of uranium was removed from the processing site, but a uranium plume still exists in the groundwater. Uranium in its reduced form is relatively insoluble in water and therefore is retained in organic rich, anoxic layers in the subsurface. However, with the aid of microbes uranium becomes soluble in water which could expose people and the environment to this toxin, if it enters the groundwater and ultimately the river. In order to better understand the mechanisms controlling uranium behavior in the floodplains, we examined sediments from three sediment cores (soil surface to aquifer). We determined the soil elemental concentrations and measured microbial activity through the use of several instruments (e.g. Elemental Analyzer, X-ray Fluorescence, MicroResp System). Through the data collected, we aim to obtain a better understanding of how the interaction of geochemical factors and microbial metabolism affect uranium mobility. This knowledge will inform models used to predict uranium behavior in response to land use or climate change in floodplain environments.

Geochemical hosts of solubilized radionuclides in uranium mill tailings

USGS Publications Warehouse

Landa, E.R.; Bush, C.A.

1990-01-01

The solubilization and subsequent resorption of radionuclides by ore components or by reaction products during the milling of uranium ores may have both economic and environmental consequences. Particle-size redistribution of radium during milling has been demonstrated by previous investigators; however, the identification of sorbing components in the tailings has received little experimental attention. In this study, uranium-bearing sandstone ore was milled, on a laboratory scale, with sulfuric acid. At regular intervals, filtrate from this suspension was placed in contact with mixtures of quartz sand and various potential sorbents which occur as gangue in uranium ores; the potential sorbents included clay minerals, iron and aluminum oxides, feldspar, fluorspar, barite, jarosite, coal, and volcanic glass. After equilibration, the quartz sand-sorbent mixtures were separated from the filtrate and radioassayed by gamma-spectrometry to determine the quantities of 238U, 230Th, 226Ra, and 210Pb sorbed, and the radon emanation coefficients. Sorption of 238U was low in all cases, with maximal sorptions of 1-2% by the bentonite- and coal-bearing samples. 230Th sorption also was generally less than 1%; maximal sorption here was observed in the fluorspar-bearing sample and appears to be associated with the formation of gypsum during milling. 226Ra and 210 Pb generally showed higher sorption than the other nuclides - more than 60% of the 26Ra solubilized from the ore was sorbed on the barite-bearing sample. The mechanism (s) for this sorption by a wide variety of substrates is not yet understood. Radon emanation coefficients of the samples ranged from about 5 to 30%, with the coal-bearing samples clearly demonstrating an emanating power higher than any of the other materials. ?? 1990.

40 CFR 440.35 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.35 Effluent limitations representing the degree of...

40 CFR 440.35 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.35 Effluent limitations representing the degree of...

40 CFR 440.35 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.35 Effluent limitations representing the degree of effluent...

40 CFR 440.35 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.35 Effluent limitations representing the degree of effluent...

40 CFR 440.35 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.35 Effluent limitations representing the degree of...

Use of X-Ray Fluorescence in a Laboratory for the Treatment of Uranium Ores; UTILISATION DE LA FLUORESCENCE DANS UN LABORATOIRE DE TRAITEMENTS DE MINERAIS D'URANIUM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillet, H.

1960-01-01

A brief description is given of some aspects of the experience gained over a year during which x-ray fluorescence was used at the laberatory of the present Section Autonome d'Etudes, Recherches et Applications Chimiques of the Commissariat a l'Energie Atomique. A standard is tested daily to ensure reproducibility. The observations made during the months from Dec. 1958 to May 1959 are described. In acid leaching of uranium ores, the residues are analyzed by x-ray fluorescence directly in powder form. Fixation and elution of vanadium on ion-exchange resin were also studied. (auth)

The next decade in geochemistry

USGS Publications Warehouse

Ingerson, E.

1958-01-01

The purpose, associations, functions; and activities of the Geochmical Society are reviewed briefly. Work on the Colorado Plateau uranium deposits is described as an example of what geochemical research, in conjunction with detailed field work, mineralogical studies, and related techniques can contribute to the understanding of a type of deposit. It is pointed out that not only have these studies given a great deal of information about the origin of the ores, but they have brought about directly a manifold increase in production and reserves of uranium in the United States. Indirectly, they aided the discovery of the tremendous deposits of the Blind River area in Ontario. It is suggested that similar broad cooperative attacks could not only yield comparable results with other types of mineral deposits, such as laterites and Mississippi Valley type lead-zinc deposits, but could also advance our knowledge and understanding of such diverse problems of geology and cosmology as the origin of granites, origin and geologic implications of meteorites (including tektites), origin and search for petroleum, and geochemical relations and interpretations of natural waters. For each of these problems methods of approach are outlined and for some of them, specific projects and correlative problems are mentioned. It is further suggested that the broad cooperative attack needed for most of these problems might be fostered most effectively by a programme comparable to that of the I.G.Y., even though for most types of geochemical research synoptic sampling and observations are not as important as they are for many projects in geophysics. ?? 1958.

Geology of the Wood and East Calhoun mines, Central City District, Gilpin County, Colorado

USGS Publications Warehouse

Drake, Avery Ala

1955-01-01

The Wood-East Calhoun mine area is underlain by complexly folded Precambrian gneiss and pegmatite. The major fold in the area is an anticline that trends about N. 60° E. The Precambrian rocks are intruded by bostonite porphyry dikes of Tertiary age. All the rocks are cut by east- to northeast - trending faults that have been filled by precious metal-sulfide veins which have been worked chiefly for gold. The Wood vein occurs in an east-trending fault; the Calhoun vein occurs in a northeast-trending fault. Much of the uranium production of the Central City district has come from the Wood vein on Quartz Hill. The veins consist chiefly of quartz; pyrite is the chief metallic mineral and chalcopyrite is next in abundance. Sphalerite, galena, tetrahedrite-tennantite, and pitchblende are locally present. Deposition began with alteration-stage quartz and pyrite followed in order by pitchblend, light-yellow pyrite, massive quartz, yellow pyrite, shalerite, comb quartz, chalcopyrite, tetrahedrite-tennantite, galena, chalcopyrite, pyrite, and gray to light-brown fine-grained quartz. The veins of the Central City district are zoned, with quartz-pyrite veins near the center and galena-sphalerite veins on the periphery. The known pitchblende bodies are in the transition between these, but paragenetically, the pitchblende is earlier than all other metallic minerals. A trace element study of the ore indicates an association of zirconium and molybdenum with uranium, of bismuth, antimony, and arsenic with copper, and of cadmium with zinc. The pitchblende and other ore minerals are concentrated in ore shoots. The shoots are in open spaces controlled by the competency of the wall rocks, the presence of a prevailing direction of weakness in the rocks, and changes in strike and dip of the vein. The pitchblende is thought to be a local constituent of the quartz-pyrite ores and to owe its origin to residual solutions from the quartz bostonite magma.

U.S.-Australia Civilian Nuclear Cooperation: Issues for Congress

DTIC Science & Technology

2010-12-01

Enrichment.......................................................................................................7 Uranium Mining and Milling...Issues for Congress Congressional Research Service 7 The nuclear fuel cycle begins with mining uranium ore and upgrading it to yellowcake. Because...uranium after the mining and milling stage. Commercial enrichment services are available in the United States, Europe, Russia, and Japan. Fuel

URANIUM COMPOSITIONS

DOEpatents

Allen, N.P.; Grogan, J.D.

1959-05-12

This patent relates to high purity uranium alloys characterized by improved stability to thermal cycling and low thermal neutron absorption. The high purity uranium alloy contains less than 0.1 per cent by weight in total amount of any ore or more of the elements such as aluminum, silicon, phosphorous, tin, lead, bismuth, niobium, and zinc.

Exposure pathways and health effects associated with chemical and radiological toxicity of natural uranium: a review.

PubMed

Brugge, Doug; de Lemos, Jamie L; Oldmixon, Beth

2005-01-01

Natural uranium exposure derives from the mining, milling, and processing of uranium ore, as well as from ingestion of groundwater that is naturally contaminated with uranium. Ingestion and inhalation are the primary routes of entry into the body. Absorption of uranium from the lungs or digestive track is typically low but can vary depending on compound specific solubility. From the blood, two-thirds of the uranium is excreted in urine over the first 24 hours and up to 80% to 90% of uranium deposited in the bone leaves the body within 1.5 years. The primary health outcomes of concern documented with respect to uranium are renal, developmental, reproductive, diminished bone growth, and DNA damage. The reported health effects derive from experimental animal studies and human epidemiology. The Lowest Observed Adverse Effect Level (LOAEL) derived from animal studies is 50 microg/m3 for inhalation and 60 ug/kg body weight/day for ingestion. The current respiratory standard of the Occupational Safety and Health Administration (OSHA), 50 microg/m3, affords no margin of safety. Considering the safety factors for species and individual variation, the ingestion LOAEL corresponds to the daily consumption set by the World Health Organization Drinking Water Standard at 2 microg/L. Based on economic considerations, the United States Environmental Protection Agency maximum contaminant level is 30 microg/L. Further research is needed, with particular attention on the impact of uranium on indigenous populations, on routes of exposure in communities near uranium sites, on the combined exposures present at many uranium sites, on human developmental defects, and on health effects at or below established exposure standards.

Molybdenum isotope fractionation during acid leaching of a granitic uranium ore

NASA Astrophysics Data System (ADS)

Migeon, Valérie; Bourdon, Bernard; Pili, Eric; Fitoussi, Caroline

2018-06-01

As an attempt to prevent illicit trafficking of nuclear materials, it is critical to identify the origin and transformation of uranium materials from the nuclear fuel cycle based on chemical and isotope tracers. The potential of molybdenum (Mo) isotopes as tracers is considered in this study. We focused on leaching, the first industrial process used to release uranium from ores, which is also known to extract Mo depending on chemical conditions. Batch experiments were performed in the laboratory with pH ranging from 0.3 to 5.5 in sulfuric acid. In order to span a large range in uranium and molybdenum yields, oxidizers such as nitric acid, hydrogen peroxide and manganese dioxide were also added. An enrichment in heavy Mo isotopes is produced in the solution during leaching of a granitic uranium ore, when Mo recovery is not quantitative. At least two Mo reservoirs were identified in the ore: ∼40% as Mo oxides soluble in water or sulfuric acid, and ∼40% of Mo hosted in sulfides soluble in nitric acid or hydrogen peroxide. At pH > 1.8, adsorption and/or precipitation processes induce a decrease in Mo yields with time correlated with large Mo isotope fractionations. Quantitative models were used to evaluate the relative importance of the processes involved in Mo isotope fractionation: dissolution, adsorption, desorption, precipitation, polymerization and depolymerization. Model best fits are obtained when combining the effects of dissolution/precipitation, and adsorption/desorption onto secondary minerals. These processes are inferred to produce an equilibrium isotope fractionation, with an enrichment in heavy Mo isotopes in the liquid phase and in light isotopes in the solid phase. Quantification of Mo isotope fractionation resulting from uranium leaching is thus a promising tool to trace the origin and transformation of nuclear materials. Our observations of Mo leaching are also consistent with observations of natural Mo isotope fractionation taking place during chemical weathering in terrestrial environments where the role of secondary processes such as adsorption is significant.

Translations on Eastern Europe, Scientific Affairs, Number 543

DTIC Science & Technology

1977-04-29

They are economically more effective than those now used, for one gram of glass can replace ten kilograms of copper wire. For several years such a...and 62 times for nonferrous ores, the greatest increase being recorded for copper bearing ores. 1. Iron Ores Overall, the iron ore deposits which...percent S. 30 Intensive research and design work is being conducted to exploit two deposits of poor copper ore (0.25-D.35 percent Cu), a deposit of

40 CFR 190.12 - Effective date.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Uranium Fuel Cycle § 190.12 Effective date. (a) The standards in § 190.10(a) shall be effective December 1, 1979, except that for doses arising from operations associated with the milling of uranium ore the...

Fluid inclusion characteristics and geological significance of the Dajinshan W-Sn polymetallic deposit in Yunfu, Guangdong Province

NASA Astrophysics Data System (ADS)

Yu, Zhangfa; Chen, Maohong; Zhao, Haijie

2015-05-01

The Dajinshan tungsten-tin polymetallic deposit is a quartz-vein-type ore deposit located in Western Guangdong Province. The ore bodies show a fairly simple shape and mainly occur as tungsten-tin polymetallic-bearing sulfide quartz veins, including quartz vein, quartz-greisens, and sulfide quartz veins, and their distribution is spatially related to Dajinshan granitoids. The formation of the deposit experienced three stages: a wolframite-molybdenite-quartz stage, a wolframite-cassiterite-sulfide-quartz stage, and a fluorite-calcite-carbonate stage. Based on detailed petrographic observations, we conducted microthermometric and Raman microspectroscopic studies of fluid inclusions formed at different ore-forming stages in the Dajinshan tungsten-tin polymetallic deposit, identifying four dominant types of fluid inclusions: aqueous two-phase inclusions, CO2-bearing inclusions, solid or daughter mineral-bearing inclusions, and gas-rich inclusions. The gas compositions of ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit are mostly CO2, CH4, and H2O. The hydrogen, oxygen, and sulfur isotopic data imply that the ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit were mainly derived from magmatic fluids, mixed with meteoric water in the ore-formation process. These results indicate that the fluid mixing and boiling led to the decomposition of the metal complex in ore-forming fluids and ore deposition.

Clay minerals trap hydrogen in the Earth's crust: Evidence from the Cigar Lake uranium deposit, Athabasca

NASA Astrophysics Data System (ADS)

Truche, Laurent; Joubert, Gilles; Dargent, Maxime; Martz, Pierre; Cathelineau, Michel; Rigaudier, Thomas; Quirt, David

2018-07-01

Hydrogen (H2)-rich fluids are observed in a wide variety of geologic settings including gas seeps in serpentinized ultramafic rocks, sub-seafloor hydrothermal vents, fracture networks in crystalline rocks from continental and oceanic crust, and volcanic gases. Natural hydrogen sources can sustain deep microbial ecosystems, induce abiotic hydrocarbons synthesis and trigger the formation of prebiotic organic compounds. However, due to its extreme mobility and small size, hydrogen is not easily trapped in the crust. If not rapidly consumed by redox reactions mediated by bacteria or suitable mineral catalysts it diffuses through the rocks and migrates toward the surface. Therefore, H2 is not supposed to accumulate in the crust. We challenge this view by demonstrating that significant amount of H2 may be adsorbed by clay minerals and remain trapped beneath the surface. Here, we report for the first time H2 content in clay-rich rocks, mainly composed of illite, chlorite, and kaolinite from the Cigar Lake uranium ore deposit (northern Saskatchewan, Canada). Thermal desorption measurements reveal that H2 is enriched up to 500 ppm (i.e. 0.25 mol kg-1 of rock) in these water-saturated rocks having a very low total organic content (<0.5 wt%). Such hydrogen uptake is comparable and even exceeds adsorbed methane capacities reported elsewhere for pure clay minerals or shales. Sudoite (Al-Mg di-trioctahedral chlorite) is probably the main mineral responsible for H2 adsorption in the present case. The presence of multiple binding sites in interlinked nanopores between crystal layers of illite-chlorite particles offers the ideal conditions for hydrogen sorption. We demonstrate that 4 to 17% of H2 produced by water radiolysis over the 1.4-Ga-lifetime of the Cigar Lake uranium ore deposit has been trapped in the surrounding clay alteration haloes. As a result, sorption processes on layered silicates must not be overlooked as they may exert an important control on the fate and mobility of H2 in the crust. Furthermore, the high capacity of clay minerals to sorb molecular hydrogen may also open up new opportunities for exploration of unexpected energy resources and for H2 storage based on geo-inspired materials.

76 FR 60941 - Policy Regarding Submittal of Amendments for Processing of Equivalent Feed at Licensed Uranium...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-30

... State-licensed uranium recovery site, either conventional, heap leach, or in situ recovery. DATES... types of new uranium recovery facilities (conventional mills, heap leach facilities, and in situ... from the ground for processing at a mill. Rather, the ore is processed in-situ with the resulting...

Development of experimental approach to examine U occurrence continuity over the extended area reconnoitory boreholes: Lostoin Block, West Khasi Hills district, Meghalaya (India).

PubMed

Kukreti, B M; Kumar, Pramod; Sharma, G K

2015-10-01

Exploratory drilling was undertaken in the Lostoin block, West Khasi Hills district of Meghalaya based on the geological extension to the major uranium deposit in the basin. Gamma ray logging of drilled boreholes shows considerable subsurface mineralization in the block. However, environmental and exploration related challenges such as climatic, logistic, limited core drilling and poor core recovery etc. in the block severely restricted the study of uranium exploration related index parameters for the block with a high degree confidence. The present study examines these exploration related challenges and develops an integrated approach using representative sampling of reconnoitory boreholes in the block. Experimental findings validate a similar geochemically coherent nature of radio elements (K, Ra and Th) in the Lostoin block uranium hosting environment with respect to the known block of Mahadek basin and uranium enrichment is confirmed by the lower U to Th correlation index (0.268) of hosting environment. A mineralized zone investigation in the block shows parent (refers to the actual parent uranium concentration at a location and not a secondary concentration such as the daughter elements which produce the signal from a total gamma ray measurement) favoring uranium mineralization. The confidence parameters generated under the present study have implications for the assessment of the inferred category of uranium ore in the block and setting up a road map for the systematic exploration of large uranium potential occurring over extended areas in the basin amid prevailing environmental and exploratory impediments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Urinary excretion of uranium in adult inhabitants of the Czech Republic.

PubMed

Malátová, Irena; Bečková, Věra; Kotík, Lukáš

2016-02-01

The main aim of this study was to determine and evaluate urinary excretion of uranium in the general public of the Czech Republic. This value should serve as a baseline for distinguishing possible increase in uranium content in population living near legacy sites of mining and processing uranium ores and also to help to distinguish the proportion of the uranium content in urine among uranium miners resulting from inhaled dust. The geometric mean of the uranium concentration in urine of 74 inhabitants of the Czech Republic was 0.091 mBq/L (7.4 ng/L) with the 95% confidence interval 0.071-0.12 mBq/L (5.7-9.6 ng/L) respectively. The geometric mean of the daily excretion was 0.15 mBq/d (12.4 ng/d) with the 95% confidence interval 0.12-0.20 mBq/d (9.5-16.1 ng/d) respectively. Despite the legacy of uranium mines and plants processing uranium ore in the Czech Republic, the levels of uranium in urine and therefore, also human body content of uranium, is similar to other countries, esp. Germany, Slovenia and USA. Significant difference in the daily urinary excretion of uranium was found between individuals using public supply and private water wells as a source of drinking water. Age dependence of daily urinary excretion of uranium was not found. Mean values and their range are comparable to other countries, esp. Germany, Slovenia and USA. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of microwaves on the leaching kinetics of uraninite from a low grade ore in dilute sulfuric acid.

PubMed

Madakkaruppan, V; Pius, Anitha; T, Sreenivas; Giri, Nitai; Sarbajna, Chanchal

2016-08-05

This paper describes a study on microwave assisted leaching of uranium from a low-grade ore of Indian origin. The host rock for uranium mineralization is chlorite-biotite-muscovite-quartzo-feldspathic schist. The dominant presence of siliceous minerals determined leaching of uranium values in sulfuric acid medium under oxidizing conditions. Process parametric studies like the effect of sulfuric acid concentration (0.12-0.50M), redox potential (400-500mV), particle size (600-300μm) and temperature (35°-95°C) indicated that microwave assisted leaching is more efficient in terms of overall uranium dissolution, kinetics and provide relatively less impurities (Si, Al, Mg and Fe) in the leach liquor compared to conventional conductive leaching. The kinetics of leaching followed shrinking core model with product layer diffusion as controlling mechanism. Copyright © 2016 Elsevier B.V. All rights reserved.

Mineralogy and geochemistry of vanadium in the Colorado Plateau

USGS Publications Warehouse

Weeks, A.D.

1961-01-01

The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin. ?? 1961.

40 CFR 440.31 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false [Reserved] 440.31 Section 440.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440...

40 CFR 440.31 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false [Reserved] 440.31 Section 440.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440...

40 CFR 440.31 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false [Reserved] 440.31 Section 440.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.31...

40 CFR 440.31 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false [Reserved] 440.31 Section 440.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440...

40 CFR 440.31 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false [Reserved] 440.31 Section 440.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.31...

Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings (40 CFR Part 192)

EPA Pesticide Factsheets

This regulation sets standards for the protection of public health, safety, and the environment from radiological and non-radiological hazards from uranium and thorium ore processing and disposal of associated wastes.

Occurrence model for volcanogenic beryllium deposits: Chapter F in Mineral deposit models for resource assessment

USGS Publications Warehouse

Foley, Nora K.; Hofstra, Albert H.; Lindsey, David A.; Seal, Robert R.; Jaskula, Brian W.; Piatak, Nadine M.

2012-01-01

Current global and domestic mineral resources of beryllium (Be) for industrial uses are dominated by ores produced from deposits of the volcanogenic Be type. Beryllium deposits of this type can form where hydrothermal fluids interact with fluorine and lithophile-element (uranium, thorium, rubidium, lithium, beryllium, cesium, tantalum, rare earth elements, and tin) enriched volcanic rocks that contain a highly reactive lithic component, such as carbonate clasts. Volcanic and hypabyssal high-silica biotite-bearing topaz rhyolite constitutes the most well-recognized igneous suite associated with such Be deposits. The exemplar setting is an extensional tectonic environment, such as that characterized by the Basin and Range Province, where younger topaz-bearing igneous rock sequences overlie older dolomite, quartzite, shale, and limestone sequences. Mined deposits and related mineralized rocks at Spor Mountain, Utah, make up a unique economic deposit of volcanogenic Be having extensive production and proven and probable reserves. Proven reserves in Utah, as reported by the U.S. Geological Survey National Mineral Information Center, total about 15,900 tons of Be that are present in the mineral bertrandite (Be4Si2O7(OH)2). At the type locality for volcanogenic Be, Spor Mountain, the tuffaceous breccias and stratified tuffs that host the Be ore formed as a result of explosive volcanism that brought carbonate and other lithic fragments to the surface through vent structures that cut the underlying dolomitic Paleozoic sedimentary rock sequences. The tuffaceous sediments and lithic clasts are thought to make up phreatomagmatic base surge deposits. Hydrothermal fluids leached Be from volcanic glass in the tuff and redeposited the Be as bertrandite upon reaction of the hydrothermal fluid with carbonate clasts in lithic-rich sections of tuff. The localization of the deposits in tuff above fluorite-mineralized faults in carbonate rocks, together with isotopic evidence for the involvement of magmatic water in an otherwise meteoric water-dominated hydrothermal system, indicate that magmatic volatiles contributed to mineralization. At the type locality, hydrothermal alteration of dolomite clasts formed layered nodules of calcite, opal, fluorite, and bertrandite, the latter occurring finely intergrown with fluorite. Alteration assemblages and elemental enrichments in the tuff and surrounding volcanic rocks include regional diagenetic clays and potassium feldspar and distinctive hydrothermal halos of anomalous fluorine, lithium, molybdenum, niobium, tin, and tantalum, and intense potassium feldspathization with sericite and lithium-smectite in the immediate vicinity of Be ore. Formation of volcanogenic Be deposits is due to the coincidence of multiple factors that include an appropriate Be-bearing source rock, a subjacent pluton that supplied volatiles and heat to drive convection of meteoric groundwater, a depositional site characterized by the intersection of normal faults with permeable tuff below a less permeable cap rock, a fluorine-rich ore fluid that facilitated Be transport (for example, BeF42- complex), and the existence of a chemical trap that caused fluorite and bertrandite to precipitate at the former site of carbonate lithic clasts in the tuff.

Morphological Comparison of U3O8 Ore Concentrates from Canada Key Lake and Namibia Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Daniel S.; Tandon, Lav; Martinez, Patrick Thomas

Uranium ore concentrates from two different sources were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The ore powders are referred to as Namibia (id. no. 90036, LIMS id. no. 18775) and Canada Key Lake (id. no. 90019, LIMS id. no. 18774). Earlier work identified the ores as the U₃O₈ phase of uranium oxide using x-ray diffraction. Both sets of powders were in the form of dark brown to black powder fines. However, the Canada Key Lake concentrates contained larger chunks of material on the millimeter scale that were easily visible to the unaided eye. The powdersmore » were mounted for SEM examination by hand dispersing a small amount onto conductive sticky tape. Two types of applicators were used and compared: a fine-tipped spatula and a foam-tipped applicator. The sticky tape was on a standard SEM “tee” mount, which was tapped to remove loose contamination before being inserted into the SEM.« less

Assessment of (222)Rn emanation from ore body and backfill tailings in low-grade underground uranium mine.

PubMed

Mishra, Devi Prasad; Sahu, Patitapaban; Panigrahi, Durga Charan; Jha, Vivekanand; Patnaik, R Lokeswara

2014-02-01

This paper presents a comparative study of (222)Rn emanation from the ore and backfill tailings in an underground uranium mine located at Jaduguda, India. The effects of surface area, porosity, (226)Ra and moisture contents on (222)Rn emanation rate were examined. The study revealed that the bulk porosity of backfill tailings is more than two orders of magnitude than that of the ore. The geometric mean radon emanation rates from the ore body and backfill tailings were found to be 10.01 × 10(-3) and 1.03 Bq m(-2) s(-1), respectively. Significant positive linear correlations between (222)Rn emanation rate and the (226)Ra content of ore and tailings were observed. For normalised (226)Ra content, the (222)Rn emanation rate from tailings was found to be 283 times higher than the ore due to higher bulk porosity and surface area. The relative radon emanation from the tailings with moisture fraction of 0.14 was found to be 2.4 times higher than the oven-dried tailings. The study suggested that the mill tailings used as a backfill material significantly contributes to radon emanation as compared to the ore body itself and the (226)Ra content and bulk porosity are the dominant factors for radon emanation into the mine atmosphere.

Remote sensing strategic exploration of large or superlarge gold ore deposits

NASA Astrophysics Data System (ADS)

Yan, Shouxun; Liu, Qingsheng; Wang, Hongmei; Wang, Zhigang; Liu, Suhong

1998-08-01

To prospect large or superlarge gold ore deposits, blending of remote sensing techniques and modern metallogenitic theories is one of the effective measures. The theory of metallogeny plays a director role before and during remote sensing technique applications. The remote sensing data with different platforms and different resolutions can be respectively applied to detect direct or indirect metallogenic information, and to identify the ore-controlling structure, especially, the ore-controlling structural assemblage, which, conversely, usually are the new conditions to study and to modify the metallogenic model, and to further develop the exploration model of large or superlarge ore deposits. Guidance by an academic idea of 'adjustment structure' which is the conceptual model of transverse structure, an obscured ore- controlling transverse structure has been identified on the refined TM imagery in the Hadamengou gold ore deposit, Setai Hyperspectral Geological Remote Sensing Testing Site (SHGRSTS), Wulashan mountains, Inner Mongolia, China. Meanwhile, The MAIS data has been applied to quickly identify the auriferous alteration rocks with Correspondence Analysis method and Spectral Angle Mapping (SAM) technique. The theoretical system and technical method of remote sensing strategic exploration of large or superlarge gold ore deposits have been demonstrated by the practices in the SHGRSTS.

Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger.

PubMed

Déjeant, Adrien; Galoisy, Laurence; Roy, Régis; Calas, Georges; Boekhout, Flora; Phrommavanh, Vannapha; Descostes, Michael

2016-03-01

This study investigated the evolution of uranium distribution and speciation in mill tailings from the COMINAK mine (Niger), in production since 1978. A multi-scale approach was used, which combined high resolution remote sensing imagery, ICP-MS bulk rock analyses, powder X-ray diffraction, Scanning Electron Microscopy, Focused Ion Beam--Transmission Electron Microscopy and X-ray Absorption Near Edge Spectroscopy. Mineralogical analyses showed that some ore minerals, including residual uraninite and coffinite, undergo alteration and dissolution during tailings storage. The migration of uranium and other contaminants depends on (i) the chemical stability of secondary phases and sorbed species (dissolution and desorption processes), and (ii) the mechanical transport of fine particles bearing these elements. Uranium is stabilized after formation of secondary uranyl sulfates and phosphates, and adsorbed complexes on mineral surfaces (e.g. clay minerals). In particular, the stock of insoluble uranyl phosphates increases with time, thus contributing to the long-term stabilization of uranium. At the surface, a sulfate-cemented duricrust is formed after evaporation of pore water. This duricrust limits water infiltration and dust aerial dispersion, though it is enriched in uranium and many other elements, because of pore water rising from underlying levels by capillary action. Satellite images provided a detailed description of the tailings pile over time and allow monitoring of the chronology of successive tailings deposits. Satellite images suggest that uranium anomalies that occur at deep levels in the pile are most likely former surface duricrusts that have been buried under more recent tailings. Copyright © 2015 Elsevier B.V. All rights reserved.

Integrate metalogenic database with GIS geological project (deposite Au-Ag Far East Russia). WEB-GIS approach.

NASA Astrophysics Data System (ADS)

Kucharenko, Evgeniy; Asavin, Alex

2015-04-01

Resource depletion has forced us to search for new ore deposit and reanalyze old mineral deposits. This is the main aim of metallogenic studies. Synthesis information about features resources work out deposit and emerging fields will play a key role in future. Development of metallogeny databases is one of the most difficult tasks for Earth sciences. Database needs to enter a large number of parameters describing the object of study - mine or ore occurrence. Majority of these parameters belong to different areas of geological knowledge. It can be ore mineralogy, geochemistry, lithology of host rocks, tectonic characteristics ore-controlling structures, geochemical parameters of ore processes, geochronological data on age of geological formations and processes of ore formation and some others. However, the cartographic materials of various scales apart from diverse documentation and numerical information are of a great importance. The adopted framework for the analysis of large-scale metallogeny has several levels: 1. The ore body (usually 1: 50000, 1: 100000) 2. The ore field, the field (1: 200000) 3. The ore cluster (1: 500000) Researchers can vary scheme and scale values, but fundamentally three levels of scale describing the location and geological structures controlling the placement of ore are included at least. Attention should be pay to the system of description the ore deposit. It is necessary to create the universal scheme for development of metallogeny information systems and set up the universal algorithm of ore deposit description. There is its own order of importance of used features and a form of description for each type of deposits and ore and genetic group and ore element. Lack of definition in the classification of a particular metallogenic object makes the choice of algorithm description justified quite weakly. It is quite notable that available features which used for description of different deposit (even of the same genetic group) are not of the same type or detailed enough. Waste deposit usually takes as a reference object with the most complete description in opposite to the recently discovered deposit not enough studied and with quite limited list of information indicators. There are following most actual tasks for information metallogeny system: 1. Search summarizing the characteristics of different objects 2. Select the most informative group of features 3. Show the links of groups of signs and analyze it as far as genesis of deposits. The actual task's list could be continued but it is enough to start. Essentially mentioned problems put us in a situation when deposit's metallogenic database is not available. There is only limited number of typical databases (for certain types of minerals) characterized nothing more than name of the fields and basic indicators of its economic importance (stocks, component content, ore types). The additional information: the age of host rock or ores or geochemistry features of some geological objects uses quite rarely. There is no systematic data for all objects in the database. Database of carbonatite deposits is the most well-developed. It should be also mentioned some works [Woolley & Kjarsgaard 2009; Bagdasarov et al.,2001; Burmistrov et al., 2008]. Unfortunately, such important characteristics as geological maps are not included there as

Ores and Climate Change - Primary Shareholders

NASA Astrophysics Data System (ADS)

Stein, Holly J.; Hannah, Judith L.

2015-04-01

Many in the economic geology community concern themselves with details of ore formation at the deposit scale, whether tallying fluid inclusion data to get at changes in ore-forming fluids or defining structures that aid and abet mineralization. These compilations are generally aimed at interpretation of events at the site of ore formation, with the goal being assignment of the deposit to a sanctioned ore deposit model. While providing useful data, this approach is incomplete and does not, by itself, serve present-day requirements for true interdisciplinary science. The ore-forming environment is one of chaos and disequilibrium at nearly all scales (Stein, 2014). Chaos and complexity are documented by variably altered rocks, veins or disseminated mineralization with multi-generational fluid histories, erratic and unusual textures in host rocks, and the bitumen or other hydrocarbon products entwined within many ore deposits. This should give pause to our drive for more data as a means to find "the answer". The answer lies in the kind of data collected and more importantly, in the way we interpret those data. Rather than constructing an ever-increasing catalog of descriptive mutations on sanctioned ore deposit models (e.g., IOGC or Iron-Oxide Copper Gold deposits), the way forward is to link source and transport of metals, sulfur, and organic material with regional and ultimately whole Earth chemical evolution. Important experimental work provides chemical constraints in controlled and behaved environments. To these data, we add imagination and interpretation, always tying back to field observations. In this paper, several key points are made by way of ore deposit examples: (1) many IOCG deposits are outcomes of profound changes in the chemistry of the Earth's surface, in the interplay of the atmosphere, hydrosphere, biosphere, and lithosphere; (2) the redox history of Fe in deep earth may be ultimately expressed in the ore-forming sequence; and (3) the formation of many giant Cu-Mo-Au ore deposits may be arrested when the surface is catastrophically breached, as multiple km-scale breccia pipes empty their volatile and metal contents into the atmosphere. The new equation for studying ore geology should be one that reconstructs ore formation from beginning to end, that is, from source, release, and transport, to breach. Of course, detailed measurements and mapping of ore bodies remains essential, but a full understanding of metal migration and budgets can only be achieved if we model what might have been left behind in deeper Earth, and what may have been lost to the atmosphere. To do this, we need to understand much more than the geology at our ore deposit of interest. Stein, H.J. (2014) Dating and Tracing the History of Ore Formation. Treatise on Geochemistry 13: 87-118. Elsevier. Support for time to think - CHRONOS, funded by a consortium of Norwegian petroleum companies.

GIS prospectivity mapping and 3D modeling validation for potential uranium deposit targets in Shangnan district, China

NASA Astrophysics Data System (ADS)

Xie, Jiayu; Wang, Gongwen; Sha, Yazhou; Liu, Jiajun; Wen, Botao; Nie, Ming; Zhang, Shuai

2017-04-01

Integrating multi-source geoscience information (such as geology, geophysics, geochemistry, and remote sensing) using GIS mapping is one of the key topics and frontiers in quantitative geosciences for mineral exploration. GIS prospective mapping and three-dimensional (3D) modeling can be used not only to extract exploration criteria and delineate metallogenetic targets but also to provide important information for the quantitative assessment of mineral resources. This paper uses the Shangnan district of Shaanxi province (China) as a case study area. GIS mapping and potential granite-hydrothermal uranium targeting were conducted in the study area combining weights of evidence (WofE) and concentration-area (C-A) fractal methods with multi-source geoscience information. 3D deposit-scale modeling using GOCAD software was performed to validate the shapes and features of the potential targets at the subsurface. The research results show that: (1) the known deposits have potential zones at depth, and the 3D geological models can delineate surface or subsurface ore-forming features, which can be used to analyze the uncertainty of the shape and feature of prospectivity mapping at the subsurface; (2) single geochemistry anomalies or remote sensing anomalies at the surface require combining the depth exploration criteria of geophysics to identify potential targets; and (3) the single or sparse exploration criteria zone with few mineralization spots at the surface has high uncertainty in terms of the exploration target.

The mineral industry of Ethiopia: present conditions and future prospects

NASA Astrophysics Data System (ADS)

Assefa, Getaneh

Despite a record of mineral activity that dates back to Biblical times and the occurrence of a wide variety of minerals, as well as continuing efforts to discover major ore deposits, Ethiopia's mineral resources ahve remained of minor importance in the world economy. Mineral production in the last 20 years, for example, forms less than 1% of the estimated GDP. Well known minerals andmineral products available in the country in commercial quantities are: gold, platinum, manganese ore, natural agas, clays and clay products, feldspars, gypsum and anhydrite, slat, lime, limestone, cement, sand, structural and crushed stones, marble, mineral water and pumice. There are also vast reserves of water and geothermal power. Recently discovered deposits (over the last 20 years), with major reserves that may attain an important role in mineral production in the future, include potash salts, copper ore and diatomites. Minerals which are known to occur in Ethiopia, but of which supplies are deficient, or which have not yet been proved to exist in economic quantities are: nickel, iron, chromium, mineral fuels (oil, coal and uranium), sulphur, asbesttos, mica, talc, barytes, fluorites, borates, soda-ash, phosphates, wolframite, abrasives (garnet), molybdenite and vanadium. Within the last few years there has been an increasing appreciation of the economic significance of a mineral industry and a definite attempt to foster it. Mineral ownership is vested in the state are cotnrolled by the MInistry of Mines, Energy and Water Resources. The law relating to foreign investment in mines is liberal. The plans for the future have to provide for detailed and intensive exploration of the country's mineral resources, manufacture and fabrication.

Colloidal and physical transport textures exhibited by electrum and naumannite in bonanza epithermal veins from western USA, and their significance

USGS Publications Warehouse

Saunders, James A.; Vikre, Peter G.; Unger, Derick L.; Beasley, Lee

2010-01-01

It is reasonably clear that disequilibrium or “far-from equilibrium” conditions lead to the formation of silica colloids and their deposition in many epithermal deposits. This implies ore-forming solutions had elevated concentrations of dissolved silica, well in excess of amorphous silica saturation. We have previously demonstrated that such colloidal silica particles were deposited in epithermal veins as silica gels and opal, which may later progress along a path to crystallize into more thermodynamically favored (less-soluble) silica phases such as quartz and chalcedony. Also, in some deposits, amorphous silica is co-deposited with precious-metal minerals, such as electrum in the banded super-bonanza ores of the Sleeper deposit (NV). Ore-mineral textures from some western USA bonanza epithermal ores indicate that two precious-metal phases (electrum and naumannite, Ag2Se) form colloidal particles that are transported by ore-forming fluids and are deposited either by aggregation (by sticking to other precious metal-particles) to make dendrites, or are deposited on the “lee” side of protrusion along vein walls (or perhaps by both processes). We can infer by analogy to silica that this also implies that ore-forming solutions contained elevated (supersaturated) dissolved concentrations of both gold and silver that formed colloidal particles under disequilibrium (often chaotic) conditions. Thus physical transport and deposition textures seem to indicate the presence of strongly precious-metal-enriched ore forming fluids, which led to (not surprisingly) the bonanza grades of these remarkable ores. What causes such a precious-metal-rich solution is debatable, but that is the subject of our continued investigations.

Lead isotope studies of the Guerrero composite terrane, west-central Mexico: implications for ore genesis

NASA Astrophysics Data System (ADS)

Potra, Adriana; Macfarlane, Andrew W.

2014-01-01

New thermal ionization mass spectrometry and multi-collector inductively coupled plasma mass spectrometry Pb isotope analyses of three Cenozoic ores from the La Verde porphyry copper deposit located in the Zihuatanejo-Huetamo subterrane of the Guerrero composite terrane are presented and the metal sources are evaluated. Lead isotope ratios of 3 Cenozoic ores from the El Malacate and La Esmeralda porphyry copper deposits located in the Zihuatanejo-Huetamo subterrane and of 14 ores from the Zimapan and La Negra skarn deposits from the adjoining Sierra Madre terrane are also presented to look for systematic differences in the lead isotope trends and ore metal sources among the proposed exotic tectonostratigraphic terranes of southern Mexico. Comparison among the isotopic signatures of ores from the Sierra Madre terrane and distinct subterranes of the Guerrero terrane supports the idea that there is no direct correlation between the distinct suspect terranes of Mexico and the isotopic signatures of the associated Cenozoic ores. Rather, these Pb isotope patterns are interpreted to reflect increasing crustal contribution to mantle-derived magmas as the arc advanced eastward onto a progressively thicker continental crust. The lead isotope trend observed in Cenozoic ores is not recognized in the ores from Mesozoic volcanogenic massive sulfide and sedimentary exhalative deposits. The Mesozoic ores formed prior to the amalgamation of the Guerrero composite terrane to the continental margin, which took place during the Late Cretaceous, in intraoceanic island arc and intracontinental marginal basin settings, while the Tertiary deposits formed after this event in a continental arc setting. Lead isotope ratios of the Mesozoic and Cenozoic ores appear to reflect these differences in tectonic setting of ore formation. Most Pb isotope values of ores from the La Verde deposit (206Pb/204Pb = 18.674-18.719) are less radiogenic than those of the host igneous rocks, but plot within the field defined by the Huetamo Sequence, suggesting that these ores may also contain metals from the sedimentary rocks. The Pb isotope ratios of ore samples from the Zimapan deposit (206Pb/204Pb = 18.771-18.848) are substantially higher than the whole-rock Pb isotope compositions of the basement rocks. The similarity of ore Pb to igneous rock Pb in the Zimapan district (206Pb/204Pb = 18.800-18.968) may indicate that the proximal source of ore metals in the hydrothermal system was the igneous activity.

Quantitative radiochemical method for determination of major sources of natural radioactivity in ores and minerals

USGS Publications Warehouse

Rosholt, J.N.

1954-01-01

When an ore sample contains radioactivity other than that attributable to the uranium series in equilibrium, a quantitative analysis of the other emitters must be made in order to determine the source of this activity. Thorium-232, radon-222, and lead-210 have been determined by isolation and subsequent activity analysis of some of their short-lived daughter products. The sulfides of bismuth and polonium are precipitated out of solutions of thorium or uranium ores, and the ??-particle activity of polonium-214, polonium-212, and polonium-210 is determined by scintillation-counting techniques. Polonium-214 activity is used to determine radon-222, polonium-212 activity for thorium-232, and polonium-210 for lead-210. The development of these methods of radiochemical analysis will facilitate the rapid determination of some of the major sources of natural radioactivity.

Spatial analysis techniques applied to uranium prospecting in Chihuahua State, Mexico

NASA Astrophysics Data System (ADS)

Hinojosa de la Garza, Octavio R.; Montero Cabrera, María Elena; Sanín, Luz H.; Reyes Cortés, Manuel; Martínez Meyer, Enrique

2014-07-01

To estimate the distribution of uranium minerals in Chihuahua, the advanced statistical model "Maximun Entropy Method" (MaxEnt) was applied. A distinguishing feature of this method is that it can fit more complex models in case of small datasets (x and y data), as is the location of uranium ores in the State of Chihuahua. For georeferencing uranium ores, a database from the United States Geological Survey and workgroup of experts in Mexico was used. The main contribution of this paper is the proposal of maximum entropy techniques to obtain the mineral's potential distribution. For this model were used 24 environmental layers like topography, gravimetry, climate (worldclim), soil properties and others that were useful to project the uranium's distribution across the study area. For the validation of the places predicted by the model, comparisons were done with other research of the Mexican Service of Geological Survey, with direct exploration of specific areas and by talks with former exploration workers of the enterprise "Uranio de Mexico". Results. New uranium areas predicted by the model were validated, finding some relationship between the model predictions and geological faults. Conclusions. Modeling by spatial analysis provides additional information to the energy and mineral resources sectors.

Effect of mineral constituents in the bioleaching of uranium from uraniferous sedimentary rock samples, Southwestern Sinai, Egypt.

PubMed

Amin, Maisa M; Elaassy, Ibrahim E; El-Feky, Mohamed G; Sallam, Abdel Sattar M; Talaat, Mona S; Kawady, Nilly A

2014-08-01

Bioleaching, like Biotechnology uses microorganisms to extract metals from their ore materials, whereas microbial activity has an appreciable effect on the dissolution of toxic metals and radionuclides. Bioleaching of uranium was carried out with isolated fungi from uraniferous sedimentary rocks from Southwestern Sinai, Egypt. Eight fungal species were isolated from different grades of uraniferous samples. The bio-dissolution experiments showed that Aspergillus niger and Aspergillus terreus exhibited the highest leaching efficiencies of uranium from the studied samples. Through monitoring the bio-dissolution process, the uranium grade and mineralogic constituents of the ore material proved to play an important role in the bioleaching process. The tested samples asserted that the optimum conditions of uranium leaching are: 7 days incubation time, 3% pulp density, 30 °C incubation temperature and pH 3. Both fungi produced the organic acids, namely; oxalic, acetic, citric, formic, malonic, galic and ascorbic in the culture filtrate, indicating an important role in the bioleaching processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Deposit model for volcanogenic uranium deposits

USGS Publications Warehouse

Breit, George N.; Hall, Susan M.

2011-01-01

The International Atomic Energy Agency's tabulation of volcanogenic uranium deposits lists 100 deposits in 20 countries, with major deposits in Russia, Mongolia, and China. Collectively these deposits are estimated to contain uranium resources of approximately 500,000 tons of uranium, which amounts to 6 percent of the known global resources. Prior to the 1990s, these deposits were considered to be small (less than 10,000 tons of uranium) with relatively low to moderate grades (0.05 to 0.2 weight percent of uranium). Recent availability of information on volcanogenic uranium deposits in Asia highlighted the large resource potential of this deposit type. For example, the Streltsovskoye district in eastern Russia produced more than 100,000 tons of uranium as of 2005; with equivalent resources remaining. Known volcanogenic uranium deposits within the United States are located in Idaho, Nevada, Oregon, and Utah. These deposits produced an estimated total of 800 tons of uranium during mining from the 1950s through the 1970s and have known resources of 30,000 tons of uranium. The most recent estimate of speculative resources proposed an endowment of 200,000 tons of uranium.

Determination of elemental impurities and U and O isotopic compositions with a view to identify the geographical and industrial origins of uranium ore concentrates

NASA Astrophysics Data System (ADS)

Salaun, A.; Hubert, A.; Pointurier, F.; Aupiais, J.; Pili, E.; Richon, P.; Fauré, A.; Diallo, S.

2012-12-01

First events of illicit trafficking of nuclear and radiological materials occurred 50 years ago. Nuclear forensics expertise are aiming at determining the use of seized material, its industrial history and provenance (geographical area, place of production or processing), at assisting in the identification and dismantling of illicit trafficking networks. This information is also valuable in the context of inspections of declared facilities to verify the consistency of operator's declaration. Several characteristics can be used to determine the origin of uranium ore concentrates such as trace elemental impurity patterns (Keegan et al., 2008 ; Varga et al., 2010a, 2010b) or uranium, oxygen and lead isotopic compositions (Tamborini et al., 2002a, 2002b ; Wallenius et al., 2006; Varga et al., 2009). We developed analytical procedures for measuring the isotopic compositions of uranium (234U/238U and 235U/238U) and oxygen (18O/16O) and levels of elemental impurities (e.g. REE, Th) from very small amounts of uranium ore concentrates (or yellow cakes). Micrometer particles and few milligrams of material are used for oxygen isotope measurements and REE determination, respectively. Reference materials were analyzed by mass spectrometry (TIMS, SF-ICP-MS and SIMS) to validate testing protocols. Finally, materials of unknown origin were analyzed to highlight significant differences and determine whether these differences allow identifying the origin of these ore concentrates. References: Keegan, E., et al. (2008). Applied Geochemistry 23, 765-777. Tamborini, G., et al. (2002a). Analytical Chemistry 74, 6098-6101. Tamborini, G., et al. (2002b). Microchimica Acta 139, 185-188. Varga, Z., et al. (2009). Analytical Chemistry 81, 8327-8334. Varga, Z., et al. (2010a). Talanta 80, 1744-1749. Varga, Z., et al. (2010b). Radiochimica Acta 98, 771-778 Wallenius, M., et al. (2006). Forensic Science International 156, 55-62.

Geology and ore deposits of the Klondike Ridge area, Colorado

USGS Publications Warehouse

Vogel, John David

1960-01-01

The region described in this report is in the northeastern part of the Colorado Plateau and is transitional between two major structural elements. The western part is typical of the salt anticline region of the Plateau, but the eastern part has features which reflect movements in the nearby San Juan Mountains. There are five major structural elements in the report area: the Gypsum Valley anticline, Dry Creek Basin, the Horse Park fault block, Disappointment Valley, and the Dolores anticline. Three periods of major uplift are recognized In the southeastern end of the Gypsum Valley anticline. Each was followed by collapse of the overlying strata. Erosion after the first two periods removed nearly all topographic relief over the anticline; erosion after the last uplift has not yet had a profound effect on the topography except where evaporite beds are exposed at the surface. The first and greatest period of salt flow and anticlinal uplift began in the late Pennsylvanian and continued intermittently and on an ever decreasing scale into the Early Cretaceous. Most movement was in the Permian and Triassic periods. The second period of uplift and collapse was essentially contemporaneous with widespread tectonic activity on. the northwestern side of the San Juan Mountains and may have Occurred in the Oligocene and Miocene epochs. Granogabbro sills and dikes were intruded during the middle or upper Tertiary in Disappointment Valley and adjoining parts of the Gypsum Valley and Dolores anticlines. The third and mildest period of uplift occurred in the Pleistocene and was essentially contemporaneous with the post-Hinsdale uplift of the San Juan Mountains. This uplift began near the end of the earliest, or Cerro, stage of glaciation. Uranium-vanadium, manganese, and copper ore as well as gravel have been mined in the Klondike district. All deposits are small, and few have yielded more than 100 tons of ore. Most of the latter are carnotite deposits. Carnotite occurs in the lower part of the basal sandstone unit of the Salt Wash member of the Morrison formation. Most deposits are in a narrow, elongate mineral belt' that cuts obliquely across Klondike Ridge. The remaining deposits probably form a second 'mineral belt' lying about ? mile to the north. Manganese and copper deposits show both stratigraphic and structural controls of mineralization. Most manganese deposits are in red beds near Tertiary faults; most copper deposits, on the other hand, are in brown sandstone, limestone, or gray-green shale and, like manganese, are in or near Tertiary faults. The manganese and copper deposits are hydrothermal in origin and were formed in the roots of an ancient hot springs system, now deeply eroded. The ore-bearing solutions probably consisted of dilute, carbonate-sulfate ground water heated by the near-surface intrusion of small bodies of igneous rock. These solutions obtained their metals by leaching the wallrock; little, if any, material was added by the intrusives. The deposits were formed near the surface under conditions of hydrostatic pressure, and temperatures and pressures in the ore-bearing solutions were probably low. The early solutions were weakly alkaline and reducing in character. A convection cell was established as mineralization progressed, and surface water mingled at depth with the solutions. As a result of mixing and oxidation, the pH of the solution decreased in later stages of mineralization and the Eh rose.

The Luanchuan Mo-W-Pb-Zn-Ag magmatic-hydrothermal system in the East Qinling metallogenic belt, China: Constrains on metallogenesis from C-H-O-S-Pb isotope compositions and Rb-Sr isochron ages

NASA Astrophysics Data System (ADS)

Cao, Hua-Wen; Zhang, Shou-Ting; Santosh, M.; Zheng, Luo; Tang, Li; Li, Dong; Zhang, Xu-Huang; Zhang, Yun-Hui

2015-11-01

The Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore district is located in the East Qinling metallogenic belt on the southern margin of the North China Craton. Two ore fields (Nannihu and Yuku) are recognized in the district, and three types of deposits are identified from the two ore fields as follows: (1) the 6 proximal porphyry-skarn type Mo-W deposits occurring at the inner contact zone of the granite porphyries, (2) the 3 middle skarn-hydrothermal type Zn deposits, and (3) the 8 distal hydrothermal type Pb-Zn-Ag deposits at the periphery of the porphyry. We present C-H-O isotope compositions of hydrothermal quartz and calcite, S-Pb isotope compositions of sulfide minerals, and sphalerite Rb-Sr isochron ages from the 17 deposits. The geochemical and geochronological data from the two ore fields all show systematic temporal and spatial variation, and primarily lead to the following inferences. (1) The temperatures and salinities of the ore-forming fluids decreased during mineralization. The ore-forming fluids gradually evolved from magmatic water to mixed magmatic-meteoric water. (2) The metallogenic components were primarily derived from igneous rocks, with increasing proportions of the materials from the ore-bearing rocks. (3) The mineralization ages of these deposits are close (147-136 Ma), which correspond to the emplacement of the granite intrusions. (4) The three types of deposits and the ore-related late Mesozoic intrusives constitute a unified magmatic-hydrothermal-mineralization system. Finally, we also suggest exploration strategies for the Luanchuan ore district.

PROCESS FOR THE RECOVERY OF METALS FROM HIGH-LIME CARNOTITE ORES

DOEpatents

Grinstead, R.R.

1959-01-20

A process is presented for recovering uranium values from a high-lime carnotite ore comprising contacting the ore dispersed in a finely divided state with a concentrated mineral acid, adding an industrial orgnnic solvent containing alkyl ontho or pyro phosphoric acids, alkyl phosphates or alkyl phosphonates so as to effect an organic phase into which the metal value is leached and then recovering the metal value from the organic phase.

U-Pb isotope systematics and age of uranium mineralization, Midnite mine, Washington.

USGS Publications Warehouse

Ludwig, K. R.; Nash, J.T.; Naeser, C.W.

1981-01-01

Uranium ores at the Midnite mine, near Spokane, Washington, occur in phyllites and calcsilicates of the Proterozoic Togo Formation, near the margins of an anomalously uraniferous, porphyritic quartz monzonite of Late Cretaceous age. The present geometry of the ore zones is tabular, with the thickest zones above depressions in the pluton-country rock contact. Analyses of high-grade ores from the mine define a 207 Pb/ 204 Pb- 235 U/ 204 Pb isochron indicating an age of mineralization of 51.0 + or - 0.5 m.y. This age coincides with a time of regional volcanic activity (Sanpoil Volcanics), shallow intrusive activity, erosion, and faulting. U-Th-Pb isotopic ages of zircons from the porphyritic quartz monzonite in the mine indicate an age of about 75 m.y., hence the present orebodies were formed about 24 m.y. after its intrusion. The 51-m.y. time of mineralization probably represents a period of mobilization and redeposition of uranium by supergene ground waters, perhaps aided by mild heating and ground preparation and preserved by a capping of newly accumulated, impermeable volcanic rocks. It seems most likely that the initial concentration of uranium occurred about 75 m.y. ago, probably from relatively mild hydrothermal fluids in the contact-metamorphic aureole of the U-rich porphyritic quartz monzonite.Pitchblende, coffinitc, pyrite, marcasite, and hisingerite are the most common minerals in the uranium-bearing veinlets, with minor sphalerite and chalcopyrite. Coffinitc with associated marcasite is paragenetically later than pitchblende, though textural and isotopic evidence suggests no large difference in the times of pitchblende and colfinite formation.The U-Pb isotope systematics of total ores and of pitchblende-coffinite and pyrite-marcasite separates show that whereas open system behavior for U and Pb is essentially negligible for large (200-500 g) ore samples, Pb migration has occurred on a scale of 1 to 10 mm (out of pitchblende and coffinite and into pyrite and marcasite). Also, long-term continuous leakage of radioactive daughters of 238 U (probably 222 Rn) has occurred on scales of from approximately 100 mu m approximately 10 cm. The isotopic composition of unsupported radiogenic Pb in pyrite-marcasite seems to depend on the mineralogical microenvironment of the grains, so that the radiogenic Pb in pyrite-marcasite intimately intermixed with pitchblende-coffinite tends to be deficient in 206 Pb, and the radiogenic Pb in pyrite-marcasite in gangue tends to have excess 206 Pb. These systematics probably reflect differences between the average distances of Pb and 222 Rn diffusion since the formation of the ores.

Precipitation of lead-zinc ores in the Mississippi Valley-type deposit at Treves, Cevennes region of southern France

USGS Publications Warehouse

Leach, D.; Macquar, J.-C.; Lagneau, V.; Leventhal, J.; Emsbo, P.; Premo, W.

2006-01-01

The Trèves zinc–lead deposit is one of several Mississippi Valley-type (MVT) deposits in the Cévennes region of southern France. Fluid inclusion studies show that the ore was deposited at temperatures between approximately 80 and 150°C from a brine that derived its salinity mainly from the evaporation of seawater past halite saturation. Lead isotope studies suggest that the metals were extracted from local basement rocks. Sulfur isotope data and studies of organic matter indicate that the reduced sulfur in the ores was derived from the reduction of Mesozoic marine sulfate by thermochemical sulfate reduction or bacterially mediated processes at a different time or place from ore deposition. The large range of δ34S values determined for the minerals in the deposit (12.2–19.2‰ for barite, 3.8–13.8‰ for sphalerite and galena, and 8.7 to −21.2‰ for pyrite), are best explained by the mixing of fluids containing different sources of sulfur. Geochemical reaction path calculations, based on quantitative fluid inclusion data and constrained by field observations, were used to evaluate possible precipitation mechanisms. The most important precipitation mechanism was probably the mixing of fluids containing different metal and reduced sulfur contents. Cooling, dilution, and changes in pH of the ore fluid probably played a minor role in the precipitation of ores. The optimum results that produced the most metal sulfide deposition with the least amount of fluid was the mixing of a fluid containing low amounts of reduced sulfur with a sulfur-rich, metal poor fluid. In this scenario, large amounts of sphalerite and galena are precipitated, together with smaller quantities of pyrite precipitated and dolomite dissolved. The relative amounts of metal precipitated and dolomite dissolved in this scenario agree with field observations that show only minor dolomite dissolution during ore deposition. The modeling results demonstrate the important control of the reduced sulfur concentration on the Zn and Pb transport capacity of the ore fluid and the volumes of fluid required to form the deposit. The studies of the Trèves ores provide insights into the ore-forming processes of a typical MVT deposit in the Cévennes region. However, the extent to which these processes can be extrapolated to other MVT deposits in the Cévennes region is problematic. Nevertheless, the evidence for the extensive migration of fluids in the basement and sedimentary cover rocks in the Cévennes region suggests that the ore forming processes for the Trèves deposit must be considered equally viable possibilities for the numerous fault-controlled and mineralogically similar MVT deposits in the Cévennes region.

Biomining: metal recovery from ores with microorganisms.

PubMed

Schippers, Axel; Hedrich, Sabrina; Vasters, Jürgen; Drobe, Malte; Sand, Wolfgang; Willscher, Sabine

2014-01-01

Biomining is an increasingly applied biotechnological procedure for processing of ores in the mining industry (biohydrometallurgy). Nowadays the production of copper from low-grade ores is the most important industrial application and a significant part of world copper production already originates from heap or dump/stockpile bioleaching. Conceptual differences exist between the industrial processes of bioleaching and biooxidation. Bioleaching is a conversion of an insoluble valuable metal into a soluble form by means of microorganisms. In biooxidation, on the other hand, gold is predominantly unlocked from refractory ores in large-scale stirred-tank biooxidation arrangements for further processing steps. In addition to copper and gold production, biomining is also used to produce cobalt, nickel, zinc, and uranium. Up to now, biomining has merely been used as a procedure in the processing of sulfide ores and uranium ore, but laboratory and pilot procedures already exist for the processing of silicate and oxide ores (e.g., laterites), for leaching of processing residues or mine waste dumps (mine tailings), as well as for the extraction of metals from industrial residues and waste (recycling). This chapter estimates the world production of copper, gold, and other metals by means of biomining and chemical leaching (bio-/hydrometallurgy) compared with metal production by pyrometallurgical procedures, and describes new developments in biomining. In addition, an overview is given about metal sulfide oxidizing microorganisms, fundamentals of biomining including bioleaching mechanisms and interface processes, as well as anaerobic bioleaching and bioleaching with heterotrophic microorganisms.

A preliminary report on the rapid fluorimetric determination of uranium in low-grade ores

USGS Publications Warehouse

Grimaldi, F.S.; Levine, Harry

1950-01-01

A simple and very rapid fluorimetric procedure is described for the determination of uranium in low-grade shale and phosphate ores. The best working range is from 0.001 to about 0.04 percent U. The procedure employs batch extraction of uranium nitrate by ethyl acetate, using aluminum nitrate as the salting agent, prior to the visual fluorimetric estimation. The procedure is especially designed to save reagents; only 9.5 g of aluminum nitrate and 10 ml of ethyl acetate being used for one analysis. The solution of the sample by means of a fusion with NaOH-NaNO3 flux is rapid. After fusion the sample is immediately extracted without removing silica and other hydrolytic precipitates. Aluminum nitrate very effectively ties up fluoride and phosphate, thus eliminating steps required for their removal.

Ore Deposits Mined for Critical Elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verplanck, Philip; Kelley, Karen

Summary of deposit types containing critical elements, including, cobalt, gallium, germanium, indium, niobium, PGE, REE, rhenium, selenium, and tellurium. Includes information about ore deposit type, mineralogy, geologic setting, example deposits and districts, concentration ranges per reported resource, grade, and additional deposit notes. References are also included.

Uranium redox transition pathways in acetate-amended sediments

USGS Publications Warehouse

Bargar, John R.; Williams, Kenneth H.; Campbell, Kate M.; Long, Philip E.; Stubbs, Joanne E.; Suvorova, Elenal I.; Lezama-Pacheco, Juan S.; Alessi, Daniel S.; Stylo, Malgorzata; Webb, Samuel M.; Davis, James A.; Giammar, Daniel E.; Blue, Lisa Y.; Bernier-Latmani, Rizlan

2013-01-01

Redox transitions of uranium [from U(VI) to U(IV)] in low-temperature sediments govern the mobility of uranium in the environment and the accumulation of uranium in ore bodies, and inform our understanding of Earth’s geochemical history. The molecular-scale mechanistic pathways of these transitions determine the U(IV) products formed, thus influencing uranium isotope fractionation, reoxidation, and transport in sediments. Studies that improve our understanding of these pathways have the potential to substantially advance process understanding across a number of earth sciences disciplines. Detailed mechanistic information regarding uranium redox transitions in field sediments is largely nonexistent, owing to the difficulty of directly observing molecular-scale processes in the subsurface and the compositional/physical complexity of subsurface systems. Here, we present results from an in situ study of uranium redox transitions occurring in aquifer sediments under sulfate-reducing conditions. Based on molecular-scale spectroscopic, pore-scale geochemical, and macroscale aqueous evidence, we propose a biotic–abiotic transition pathway in which biomass-hosted mackinawite (FeS) is an electron source to reduce U(VI) to U(IV), which subsequently reacts with biomass to produce monomeric U(IV) species. A species resembling nanoscale uraninite is also present, implying the operation of at least two redox transition pathways. The presence of multiple pathways in low-temperature sediments unifies apparently contrasting prior observations and helps to explain sustained uranium reduction under disparate biogeochemical conditions. These findings have direct implications for our understanding of uranium bioremediation, ore formation, and global geochemical processes.

Remediation of uranium in-situ leaching area at Straz Pod Ralskem, Czech Republic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vokal, Vojtech; Muzak, Jiri; Ekert, Vladimir

2013-07-01

A large-scale development in exploration and production of uranium ores in the Czech Republic was done in the 2nd half of the 20. century. Many uranium deposits were discovered in the territory of the Czech Republic. One of the most considerable deposits in the Czech Republic is the site Hamr na Jezere - Straz pod Ralskem where both mining methods - the underground mining and the acidic in-situ leaching - were used. The extensive production of uranium led to widespread environmental impacts and contamination of ground waters. Over the period of 'chemical' leaching of uranium (ca. 32 years), a totalmore » of more than 4 million tons of sulphuric acid and other chemicals have been injected into the ground. Most of the products (approx. 99.5 %) of the acids reactions with the rocks are located in the Cenomanian aquifer. The contamination of Cenomanian aquifer covers the area larger then 27 km{sup 2}. The influenced volume of groundwater is more than 380 million m{sup 3}. The total amount of dissolved SO{sub 4}{sup 2-} is about 3.6 million tons. After 1990 a large-scale environmental program was established and the Czech government decided to liquidate the ISL Mine and start the remediation in 1996. The remediation consists of contaminated groundwater pumping, removing of the contaminants and discharging or reinjection of treated water. Nowadays four main remedial technological installations with sufficient capacity for reaching of the target values of remedial parameters in 2037 are used - the 'Station for Acid Solutions Liquidation No. One', the 'Mother liquor reprocessing' station, the 'Neutralization and Decontamination Station NDS 6' and the 'Neutralization and Decontamination Station NDS 10'. It is expected that the amount of withdrawn contaminants will vary from 80 000 to 120 000 tons per year. Total costs of all remediation activities are expected to be in excess of 2 billion EUR. (authors)« less

THE DETERMINATION OF THE MAJOR CONSTITUENTS OTHER THAN URANIUM IN BELGIAN CONGO ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowther, A.B.; Wright, J.S.; Bradfield, E.G.

1953-12-22

Methods for determining the major constituents of Belgian Congo ore other than uranium are reviewed. A method is given for the determination of cobalt by precipitation with potassium ethyl xanthate from a nitric acid solution of the ore. After wet oxidation of the precipitate, it is titrated potentiometrically in ammoniacal citrate solution with potassium ferricyanide. A method for the determination of silicon is given in which the silica is dehydrated by fuming with perchloric acid. After filtration and ignition, it is volatized as the fluoride, and the silica is deternfined from weight loss. Nickel is determined from a solution ofmore » the ore in nitric acid by double precipitation with dimethyl glyoxime after addition of citrate ion, hydroxylamine, and ammonia. Molybdenum is determined by precipitation as lead molybdate after preliminary separation with benzoin oxime. Aluminum is determined by precipitation as the benzoate, thioglycolic acid being used to complex the iron. The aluminum is then estimated gravimetrically with oxime. A composite method is presented for the deterndnation of lead, iron, alununum, calciuna, and magnesium. (C.J.G.)« less

Risk evaluation of uranium mining: A geochemical inverse modelling approach

NASA Astrophysics Data System (ADS)

Rillard, J.; Zuddas, P.; Scislewski, A.

2011-12-01

It is well known that uranium extraction operations can increase risks linked to radiation exposure. The toxicity of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. In areas where U mining is planned, a careful assessment of toxic and radioactive element concentrations is recommended before the start of mining activities. A background evaluation of harmful elements is important in order to prevent and/or quantify future water contamination resulting from possible migration of toxic metals coming from ore and waste water interaction. Controlled leaching experiments were carried out to investigate processes of ore and waste (leached ore) degradation, using samples from the uranium exploitation site located in Caetité-Bahia, Brazil. In experiments in which the reaction of waste with water was tested, we found that the water had low pH and high levels of sulphates and aluminium. On the other hand, in experiments in which ore was tested, the water had a chemical composition comparable to natural water found in the region of Caetité. On the basis of our experiments, we suggest that waste resulting from sulphuric acid treatment can induce acidification and salinization of surface and ground water. For this reason proper storage of waste is imperative. As a tool to evaluate the risks, a geochemical inverse modelling approach was developed to estimate the water-mineral interaction involving the presence of toxic elements. We used a method earlier described by Scislewski and Zuddas 2010 (Geochim. Cosmochim. Acta 74, 6996-7007) in which the reactive surface area of mineral dissolution can be estimated. We found that the reactive surface area of rock parent minerals is not constant during time but varies according to several orders of magnitude in only two months of interaction. We propose that parent mineral heterogeneity and particularly, neogenic phase formation may explain the observed variation of the reactive mineral surface area. The formation of coatings on dissolving mineral surfaces significantly reduces the amount of surface available to react with fluids. Our results show that negatively charged ion complexes, responsible for U transport, decreases when alkalinity and rock buffer capacity is similarly lower. Carbonate ion pairs however, may increase U mobility when radionuclide concentration is high and rock buffer capacity is low. The present work helps to orient future monitoring of this site in Brazil as well as of other sites where uranium is linked to igneous rock formations, without the presence of sulphides. Monitoring SO4 migration (in acidic leaching uranium sites) seems to be an efficient and simple way to track different hazards, especially in tropical conditions, where the succession of dry and wet periods increases the weathering action of the residual H2SO4. Nevertheless, models of risk evaluation should take into account reactive surface areas and neogenic minerals since they determine the U ion complex formation, which in turn, controls uranium mobility in natural systems. Keywords: uranium mining, reactive mineral surface area, uranium complexes, inverse modelling approach, risk evaluation

A multi-instrumental geochemical study of anomalous uranium enrichment in coal.

PubMed

Havelcová, Martina; Machovič, Vladimír; Mizera, Jiří; Sýkorová, Ivana; Borecká, Lenka; Kopecký, Lubomír

2014-11-01

Contents of uranium in coals from Odeř in the northernmost part of the Sokolov Basin, Czech Republic, in the vicinity of the well known St. Joachimsthal uranium ore deposits, reach extremely high values. In the present work, coal samples with contents of uranium ranging from 0.02 to 6 wt.% were studied. The study employing a whole complex of analytical techniques has been aimed at identification of changes in the structure of coal organic matter, which are associated with the high contents of uranium in coal. The study includes proximate and ultimate analyses, multielement analysis by instrumental neutron and photon activation analyses, micropetrographic analysis by optical microscopy, ESEM/EDX analysis of mineral matter, infrared and Raman spectroscopies, solvent extraction followed by gas chromatography with mass spectroscopy (GC/MS), and analytical pyrolysis (Py-GC/MS). The study has confirmed previously proposed explanation of uraniferous mineralization in sedimentary carboniferous substances by the mechanism of reduction and fixation of soluble U(VI) (uranyl, UO2(2+)) species (e.g., humic, carbonate/hydroxo/phosphate complexes) by sedimentary organic matter under diagenetic or hydrothermal conditions, and formation of insoluble U(IV) species as phosphate minerals and uraninite. The process is accompanied with alteration and destruction of the coal organic matter. The changes in the structure of coal organic matter involve dehydrogenation and oxidation mainly in the aliphatic, aromatic and hydroxyl structures, and an increase in aromaticity, content of ether bonds, and the degree of coalification. Copyright © 2014 Elsevier Ltd. All rights reserved.

A literature review of interaction of oxidized uranium species and uranium complexes with soluble organic matter

USGS Publications Warehouse

Jennings, Joan K.; Leventhal, J.S.

1978-01-01

Organic material is commonly found associated with uranium ores in sandstone-type deposits. This review of the literature summarizes the classes and separations of naturally occurring organic material but the emphasis is on soluble organic species. The main class of materials of interest is humic substances which are high-molecular-weight complex molecules that are soluble in alkaline solution. These humic substances are able to solubilize (make soluble) minerals and also to complex [by ion exchange and (or) chelation] many cations. The natural process of soil formation results in both mineral decomposition and element complexing by organic species. Uranium in solution, such as ground water, can form many species with other elements or complexes present depending on Eh and pH. In natural systems (oxidizing Eh, pH 5-9) the uranium is usually present as a complex with hydroxide or carbonate. Thermodynamic data for these species are presented. Interacting metals and organic materials have been observed in nature and studied in the laboratory by many workers in diverse scientific disciplines. The results are not easily compared. Measurements of the degree of complexation are reported as equilibrium stability constant determinations. This type of research has been done for Mn, Fe, Cu, Zn, Pb, Ni, Co, Mg, Ca, Al, and to a limited degree for U. The use of Conditional Stability Constants has given quantitative results in some cases. The methods utilized in experiments and calculations are reviewed.

Application of a feedforward neural network in the search for kuroko deposits in the Hokuroku District, Japan

USGS Publications Warehouse

Singer, Donald A.; Kouda, Ryoichi

1996-01-01

A feedforward neural network with one hidden layer and five neurons was trained to recognize the distance to kuroko mineral deposits. Average amounts per hole of pyrite, sericite, and gypsum plus anhydrite as measured by X-rays in 69 drillholes were used to train the net. Drillholes near and between the Fukazawa, Furutobe, and Shakanai mines were used. The training data were selected carefully to represent well-explored areas where some confidence of the distance to ore was assured. A logarithmic transform was applied to remove the skewness of distance and each variable was scaled and centered by subtracting the median and dividing by the interquartile range. The learning algorithm of annealing plus conjugate gradients was used to minimize the mean squared error of the scaled distance to ore. The trained network then was applied to all of the 152 drillholes that had measured gypsum, sericite, and pyrite. A contour plot of the neural net predicted distance to ore shows fairly wide areas of 1 km or less to ore; each of the known deposit groups is within the 1 km contour. The high and low distances on the margins of the contoured distance plot are in part the result of boundary effects of the contouring algorithm. For example, the short distances to ore predicted west of the Shakanai (Hanaoka) deposits are in basement. However, the short distances to ore predicted northeast of Furotobe, just off the figure, coincide with the location of the Nurukawa kuroko deposit and the Omaki deposit, south of the Shakanai-Hanaoka deposits, seems to be on an extension of short distance to ore contour, but is beyond the 3 km limit from drillholes. Also of interest are some areas only a few kilometers from the Fukazawa and Shakanai groups of deposits that are estimated to be many kilometers from ore, apparently reflecting the network's recognition of the extreme local variability of the geology near some deposits.

Blasting preparation for selective mining of complex structured ore deposition

NASA Astrophysics Data System (ADS)

Marinin, M. A.; Dolzhikov, V. V.

2017-10-01

Technological features of ore mining in the open pit development for processing of complex structured ore deposit of steeply falling occurrence have been considered. The technological schemes of ore bodies mining under different conditions of occurrence, consistency and capacity have been considered and offered in the paper. These technologies permit to reduce losses and dilution, but to increase the completeness and quality of mined ore. A method of subsequent selective excavation of ore bodies has been proposed. The method is based on the complex use of buffer-blasting technology for the muck mass and the principle of trim blasting at ore-rock junctions.

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent characteristic... for the extraction of uranium or from mines and mills using in situ leach methods. The Agency... Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L of this part any...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2010 CFR

2010-07-01

... uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent characteristic... for the extraction of uranium or from mines and mills using in situ leach methods. The Agency... Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L of this part any...

43 CFR 3486.3 - Enforcement.

Code of Federal Regulations, 2011 CFR

2011-10-01

... mine, the deposit being mined, valuable ore-bearing mineral deposits or other resources, or affect the... the authorized officer, and/or which threaten immediate and serious damage to the mine, the deposit being mined, valuable ore-bearing mineral deposits, or, regarding exploration, the environment, the...

Formation of albitite-hosted uranium within IOCG systems: the Southern Breccia, Great Bear magmatic zone, Northwest Territories, Canada

NASA Astrophysics Data System (ADS)

Montreuil, Jean-François; Corriveau, Louise; Potter, Eric G.

2015-03-01

Uranium and polymetallic U mineralization hosted within brecciated albitites occurs one kilometer south of the magnetite-rich Au-Co-Bi-Cu NICO deposit in the southern Great Bear magmatic zone (GBMZ), Canada. Concentrations up to 1 wt% U are distributed throughout a 3 by 0.5 km albitization corridor defined as the Southern Breccia zone. Two distinct U mineralization events are observed. Primary uraninite precipitated with or without pyrite-chalcopyrite ± molybdenite within magnetite-ilmenite-biotite-K-feldspar-altered breccias during high-temperature potassic-iron alteration. Subsequently, pitchblende precipitated in earthy hematite-specular hematite-chlorite veins associated with a low-temperature iron-magnesium alteration. The uraninite-bearing mineralization postdates sodic (albite) and more localized high-temperature potassic-iron (biotite-magnetite ± K-feldspar) alteration yet predates potassic (K-feldspar), boron (tourmaline) and potassic-iron-magnesium (hematite ± K-feldspar ± chlorite) alteration. The Southern Breccia zone shares attributes of the Valhalla (Australia) and Lagoa Real (Brazil) albitite-hosted U deposits but contains greater iron oxide contents and lower contents of riebeckite and carbonates. Potassium, Ni, and Th are also enriched whereas Zr and Sr are depleted with respect to the aforementioned albitite-hosted U deposits. Field relationships, geochemical signatures and available U-Pb dates on pre-, syn- and post-mineralization intrusions place the development of the Southern Breccia and the NICO deposit as part of a single iron oxide alkali-altered (IOAA) system. In addition, this case example illustrates that albitite-hosted U deposits can form in albitization zones that predate base and precious metal ore zones in a single IOAA system and become traps for U and multiple metals once the tectonic regime favors fluid mixing and oxidation-reduction reactions.

Intense alpha-particle emitting crystallites in uranium mill wastes

USGS Publications Warehouse

Landa, E.R.; Stieff, L.R.; Germani, M.S.; Tanner, A.B.; Evans, J.R.

1994-01-01

Nuclear emulsion microscopy has demonstrated the presence of small, intense ??-particle emitting crystallites in laboratory-produced tailings derived from the sulfuric acid milling of uranium ores. The ??-particle activity is associated with the isotope pair 210Pb 210Po, and the host mineral appears to be PbSO4 occurring as inclusions in gypsum laths. These particles represent potential inhalation hazards at uranium mill tailings disposal areas. ?? 1994.

Geological characteristics and ore-forming process of the gold deposits in the western Qinling region, China

NASA Astrophysics Data System (ADS)

Liu, Jiajun; Liu, Chonghao; Carranza, Emmanuel John M.; Li, Yujie; Mao, Zhihao; Wang, Jianping; Wang, Yinhong; Zhang, Jing; Zhai, Degao; Zhang, Huafeng; Shan, Liang; Zhu, Laimin; Lu, Rukui

2015-05-01

The western Qinling, belonging to the western part of the Qinling-Dabie-Sulu orogen between the North China Block and South China Block, is one of the most important gold regions in China. Isotopic dates suggest that the Mesozoic granitoids in the western Qinling region emplaced during the Middle-Late Triassic, and the deposits formed during the Late Triassic. Almost all gold deposits in the western Qinling region are classified as orogenic, Carlin-type, and Carlin-like gold deposits, and they are the products of Qinling Orogenesis caused by the final collision between the North China Block and the South China Block. The early subduction of the Mian-Lue oceanic crust and the latter collision between South Qinling Terrane and the South China Block along the Mian-Lue suture generated lithosphere-scale thermal anomalies to drive orogen-scale hydrothermal systems. The collision-related magmatism also provided heat source for regional ore-forming fluids in the Carlin-like gold deposits. Orogenic gold deposits such as Huachanggou, Liziyuan, and Baguamiao lie between the Shang-Dan and Mian-Lue sutures and are confined to WNW-trending brittle-ductile shear zones in Devonian and Carboniferous greenschist-facies metasedimentary rocks that were highly-deformed and regionally-metamorphosed. These deposits are typical orogenic gold deposits and formed within a Late Triassic age. The deposits show a close relationship between Au and Ag. Ores contain mainly microscopic gold, and minor electrum and visible gold, along with pyrite. The ore-forming fluids were main metamorphic fluids. Intensive tectonic movements caused by orogenesis created fluid-migrating channels for precipitation locations. Although some orogenic gold deposits occur adjacent to granitoids, mineralization is not synchronous with magmatism; that is, the granitoids have no genetic relations to orogenic gold deposits. As ore-forming fluids converged into dilated fractures during the extension stage of orogenesis, changes of physico-chemical conditions resulted in fluid immiscibility that played a key role in gold and sulfide deposition. The geochemical and mineralogical characteristics of the Carlin-type deposits in the western Qinling region are similar to those in the Carlin trend, Nevada, USA. Gold deposits such as La'erma and Jinlongshan occur mostly in the southeastern margin of the western Qinling regionic region whereas some deposits occur in its eastern part. These deposits are hosted in slightly metamorphosed Cambrian to Triassic sedimentary rocks, showing structurally- and stratigraphically-controlled features. The deposits mainly contain submicroscopic and microscopic gold in arsenian pyrite and arsenopyrite, with characteristic ore-forming elements of Au-As-Sb-Ba. The ore-forming fluids are early-stocked formation water and later-recharged meteoric water. Meteoric water apparently evolved in ore-forming fluids by circulation, indicating the extensional setting, and led to the deposition of Au and other elements in cool reactive permeable rocks at shallow levels, forming the disseminated ores. Carlin-like gold deposits occur between the Shang-Dan suture and the Fengxian-Zhen'an fault. The host rocks are mainly sedimentary rocks that underwent reconstruction through reworking by structural metamorphism. These deposits are structurally controlled by brittle-ductile shear zone and occur adjacent to granitoid plutons. The most important characteristic that differ to the orogenic and Carlin-type gold deposits is the genetic relationship with the synchronous magmatism. Gold occurs mainly as microscopic gold. Pyrite and arsenian pyrite can be recognized as gold-bearing minerals. The ore-forming fluids are main magmatic water mixed with metamorphic and/or formation water. Similar to orogenic gold deposits, fluid immiscibility caused the deposition of gold Carlin-like gold deposits.

Geology of the Anderson Mesa quadrangle, Colorado

USGS Publications Warehouse

Cater, Fred W.; Withington, C.F.

1953-01-01

The Anderson Mesa quadrangle is one of the eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of the southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteenth quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quarternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-tending folds. Conspicuous among the folds are large anticlines having cores of intrusive slat and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing many thousands of tons. The ore consists of largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

The dilemma of the Jiaodong gold deposits: Are they unique?

USGS Publications Warehouse

Goldfarb, Richard J.; Santosh, M.

2013-01-01

The ca. 126–120 Ma Au deposits of the Jiaodong Peninsula, eastern China, define the country's largest gold province with an overall endowment estimated as >3000 t Au. The vein and disseminated ores are hosted by NE- to NNE-trending brittle normal faults that parallel the margins of ca. 165–150 Ma, deeply emplaced, lower crustal melt granites. The deposits are sited along the faults for many tens of kilometers and the larger orebodies are associated with dilatational jogs. Country rocks to the granites are Precambrian high-grade metamorphic rocks located on both sides of a Triassic suture between the North and South China blocks. During early Mesozoic convergent deformation, the ore-hosting structures developed as ductile thrust faults that were subsequently reactivated during Early Cretaceous “Yanshanian” intracontinental extensional deformation and associated gold formation.Classification of the gold deposits remains problematic. Many features resemble those typical of orogenic Au including the linear structural distribution of the deposits, mineralization style, ore and alteration assemblages, and ore fluid chemistry. However, Phanerozoic orogenic Au deposits are formed by prograde metamorphism of accreted oceanic rocks in Cordilleran-style orogens. The Jiaodong deposits, in contrast, formed within two Precambrian blocks approximately 2 billion years after devolatilization of the country rocks, and thus require a model that involves alternative fluid and metal sources for the ores. A widespread suite of ca. 130–123 Ma granodiorites overlaps temporally with the ores, but shows a poor spatial association with the deposits. Furthermore, the deposit distribution and mineralization style is atypical of ores formed from nearby magmas. The ore concentration requires fluid focusing during some type of sub-crustal thermal event, which could be broadly related to a combination of coeval lithospheric thinning, asthenospheric upwelling, paleo-Pacific plate subduction, and seismicity along the continental-scale Tan-Lu fault. Possible ore genesis scenarios include those where ore fluids were produced directly by the metamorphism of oceanic lithosphere and overlying sediment on the subducting paleo-Pacific slab, or by devolatilization of an enriched mantle wedge above the slab. Both the sulfur and gold could be sourced from either the oceanic sediments or the serpentinized mantle. A better understanding of the architecture of the paleo-Pacific slab during Early Cretaceous below the eastern margin of China is essential to determination of the validity of possible models.

Sediment-hosted Pb-Zn Deposits: a global perspective

USGS Publications Warehouse

Leach, David L.; Sangster, Donald F.; Kelley, Karen D.; Large, R; Garven, G.; Allen, Craig R.

2005-01-01

Sediment-hosted Pb-Zn deposits contain the world's greatest lead and zinc resources and dominate world production of these metals. They are a chverse group of ore deposits hosted by a wide variety of carbonate and siliciclastic roch that have no obviolls genetic association with igneous activity. A nmge of ore-fortl1ing processes in a vmiety of geologic and tectonic environments created these deposits over at least two billion years of Earth history. The metals were precipitated by basinal brines in synsedimentary and early diagenetic to low-grade metamorphic environments. The deposits display a broad range of relationships to enclosing host rocks that includes stratiform, strata-bound, and discordant ores. These ores are divided into two broad subt)1Jes: Mississippi Valley-type (MVT) and sedimentmy exhalative (SEDEX), Despite the "exhalative" component inherent in the term "SEDEX," in this manusclipt, direct evidence of an exhalite in the ore or alteration component is not essential for a deposit to be classified as SEDEX. The presence of laminated sulfides parallel to bedding is assumed to be permissive evidence for exhalative ores. The chstinction between some SEDEX and MVT depOSits can be quite subjective because some SEDEX ores replaced carbonate, whereas some MVT depOSits formed in an early diagenetic environment and display laminated ore textures. Geologic and resource information are presented for 248 depositS that provide a framework to describe ,mel compare these deposits. Nine of tlle 10 largest sediment-hosted Pb-Zn deposits are SEDEX, Of the deposits that contain at least 2.5 million metric tons (Mt), there are 35 SEDEX (excluding Broken Hill-type) deposits and 15 MVT (excluding Iris-type) deposits. Despite the skewed distribution of the deposit size, the two deposits types have an excellent correlation between total tonnage and tonnage of contained metal (Pb + Zn), with a fairly consistent ratio of about lO/l, regardless of the size of the deposit or district. Zinc grades are approximately the same for both, whereas Pb and Ag grades are about 25 percent greater for SEDEX deposits. The largest difference between SEDEX and MVT deposits is their Cu content. Three times as many SEDEX deposits have reported Cu contents, and the median Cu value of SEDEX deposits is nearly double that of MVT deposits. Furthermore, grade-tonnage values for MVT deposits compared to a subset of SEDEX deposits hosted in carbonate rocks are virtually indistinguishable. The distribution of MVT deposits through geologic time shows that they are mainly a Phanerozoic phenomenon. The ages of SEDEX deposits are grouped into two major groups, one in the Proterozoic and another in the Phanerozoic, MVT deposits dominantly formed in platform carbonate sequences typically located within extensional zones inboard of orogenic belts, whereas SEDEX deposits formed in intracontinental or failed rifts, and rifted continental margins. The ages of MVT ores are generally tens of millions of years younger than their host rocks; however, a few are close <~5 m.y.) to the age of their host rocks. In the absence of direct dates for SEDEX deposits, their age of formation is generally constnuned by relationships to sedimentary or diagenetic features in the rocks. These studies suggest that deposition of SEDEX ores was coeval with sedimentation or early diagenesis, whereas some deposits formed at least 20 m.y. after sedimentation. Fluid inclusion, isotopic studies, and deposit modeling suggest that MVf and SEDEX deposits formed from basin brines with similar temperatures of mainly 90° to 200°C and lO to 30 wt percent NaCI equiv. Lead isotope compositions for MVT and SEDEX deposits show that Pb was mainly derived from a variety of crustal sources. Lead isotope compositions do not provide critelia that distinguish MVT from SEDEX subtypes. However, sulfur isotope compositions for sphalerite and galena show an apparent difference. SEDEX and MVf sulfur isotope compositions extend over a large range; however, most data for SEDEX ores have mainly positive isotopic compositions from 0 to 20 per mil. Isotopic values for MVf ores extend over a wider range and include more data with negative isotopic values. Given that there are relatively small differences between the metal character of MVT and SEDEX deposits and the fluids that deposited them, perhaps the most significant difference between these deposits is their depositional environment, which is determined by their respective tectonic settings. The contrasting tectonic setting also dictates the fundamental deposit attributes that generally set them apart, such as host-rock lithology, deposit morphology, and ore textures. Blief discussions are also presented on two controversial sets of deposits: Broken Hill-type deposits and a subset of deposits in the MVT group located in the Irish Midlands, considered by some authors to be a distinct ore type (Irish type). There are no Significant differences in grade tonnage values between MVT deposits and the subset that is described as Irish type. Most features of the Irish deposits are not distinct from the family of MVT deposits; however, the age of mineralization that is the same as or close to the age of the host rocks and the anomalously high fluid inclusion temperatures (up to 250°C) stand out as distinctly different from typical MVT ores. The dominance of bacteriogenic sulfur in the hish ores commonly ascribed as uniquely hish type is in fact no different from several MVT deposits or districts. A comparison of SEDEX and Broken Hill-type deposits shows that the latter deposits contain signiflcantly higher contents of Ag and Pb relative to SEDEX deposits. In terms of median values, Broken Hill-type deposits are almost three times more ellliched in Ag and one and a half times more enriched in Pb compared to other SEDEX deposits. Metamorphism is a charactelisoc feature but not a prerequisite for inclusion in the Broken Hill-type category, and IGlown Broken Hill-type examples appear to occur in Paleo- to Mesoproterozoic terranes. Broken Hill-type deposits remain an enigmatic grouping; however, there is sufficient evidence to support their inclusion as a separate category of SEDEX deposits.

Iron-ore resources of the United States including Alaska and Puerto Rico, 1955

USGS Publications Warehouse

Carr, Martha S.; Dutton, Carl E.

1959-01-01

The importance of iron ore, the basic raw material of steel, as a fundamental mineral, resource is shown by the fact that about 100 million long tons of steel is used annually in the economy of the United States, as compared with a combined total of about 5 million long tons of copper, lead, zinc, and aluminum. Satisfying this annual demand for steel requires about 110 million tons of iron ore and 70 million tons of scrap iron and steel. The average annual consumption of iron ore in the United States from 1951 to 1955, inclusive, was about 110 million long tons, which is about twice the annual average from 1900 to 1930. Production of iron ore in the United States in this 5-year period averaged approximately 100 million long tons annually, divided by regions as follows (in percent): Lake Superior, 84.1; southeastern, 6.7; western, 6.7; northeastern, 1.4; and central and gulf, 1.1. Mining of iron ore began in the American Colonies about 1619, and for 225 years it was limited to eastern United States where fuel and markets were readily available. Production of iron ore from the Lake Superior region began in 1846; the region became the leading domestic source by 1890, and the Mesabi range in Minnesota has been the world's most productive area since 1896. Proximity of raw materials, water transportation, and markets has resulted in centralization of the country's iron and steel industry in the lower Great Lakes area. Increased imports of iron ore being delivered to eastern United States as well as demands for steel in nearby markets have given impetus to expansion in the steel-making capacity in this area. The four chief iron-ore minerals - hematite, liminite, magnetite, and siderite - are widely distributed but only locally form deposits of sufficient tonnage and grade to be commercially valuable at the present time. The iron content of these minerals, of which hematite is the most important, ranges from 48 percent in siderite to 72 percent in magnetite, but as these minerals are associated with other rock-forming minerals, the iron content of marketable ore has a lower range from 30 to 67 percent.Chemical constituents other than iron also are important in determining the marketability of iron ore. Although some iron ores can be used in the blast furnace as mined, others must first be improved either chemically by reduction of undesirable constituents, or physically by aggregation. Phosphorus and sulfur particularly are common deleterious elements; excessive silica is also undesirable but within certain limits can be controlled by additional flux. Lime and magnesia are beneficial in specified amounts because of their fluxing qualities, and a small amount of alumina improves the fluidity of slag. Manganese is especially desirable as a deoxidizing and desulfurizing agent. Titanium, chromium, and nickel must also be considered in the use of ore containing these elements.The principal iron-ore deposits in the United States have been formed by three processes. Hematite-bearing bedded deposits such as those at Birmingham, Ala., are marine sedimentary rocks which, except for weathering along the outcrop, have remained practically unaltered since deposition. Deposits of the Lake Superior region, also in sedimentary strata, originally had a slightly lower iron content than those at-Birmingham, but ore bodies of hematite and limonite were formed by removal of other constituents in solution after deposition of the beds, with a relative increase of iron content in the material remaining. Limestone adjacent to igneous intrusions has been replaced by magnetite deposits at Cornwall, Pa., and by hematite-magnetite deposits near Cedar City, Utah. Magnetite deposits in New Jersey and in the Adirondack Mountains of New York are generally believed to have been formed by replacement of grains of other minerals in metamorphic rocks. Iron-ore resources are made up of reserves of iron ore, material usable under existing economic and technologic conditions; and potential ore, material likely to become usable under more favorable conditions. The tonnage and grade of material of combined reserves and potential ore in each of the deposits known or believed to contain at least 200,000 long tons of iron-ore resources are tabulated in this report, and numerous sources of additional information are given in a selected bibliography. The total domestic iron-ore resources are estimated at approximately 75,000 million long tons of crude ore. About 10,000 million tons of the resources is reserves of crude ore that will probably yield 5,500 million tons of concentrates and direct-shipping ore. About 65,000 million tons is potential ore and may yield 25,000 million tons of concentrates and some direct-shipping ore.

The Bairendaba silver polymetallic deposit in Inner Mongolia, China: characteristics of ore-forming fluid and genetic type of ore deposit

NASA Astrophysics Data System (ADS)

Wang, Ying; Xie, Yuling; Wu, Haoran

2018-02-01

Bairendaba silver-polymetallic deposit is located in the middle south of the Xing Meng orogenic belt, and in the silver-polymetallic metallogenic belt on the west slope of the southern of Great Xing’an Range. Based on studying of the fluid inclusion, we discuss the characteristics of ore-forming fluid and the metallic genesis of the Bairendaba silver-polymetallic deposit. By means of the analysis of the fluid inclusions, homogenization temperature, salinity and composition were studied in quartz and fluorite. The result is as the follows: with homogenization temperatures of fluid inclusions in quartz veins being 196∼312 °C, the average 244.52 °C, and fluid salinity 2.90∼9.08 wt%NaCl; with homogenization temperatures of fluid inclusions in fluorite being 127∼306 °C, the average 196.92 °C, and fluid salinity 2.90∼9.34 wt% NaCl. The ore-forming fluid is mainly composed of water and the gas. The results of laser Raman analysis show that the gas phase is mainly CH4. It shows that the ore-forming fluid is characterized by medium-low temperature and low-salinity system. The temperature of ore-forming fluid is from high to low, and the salinity from high to low, and the meteoric water or metamorphic water is added during deposit. According to the geological characteristics of the mining area, it is considered that the genetic type of the ore deposit should be the fault-controlled and the medium-low temperature hydrothermal deposit related to magmatic hydrothermal activities.

Chemical treatment of low-grade uranium ores. Extraction of uranium from tricalcium phosphate; TRAITEMENT CHIMIQUE DES MINERAIS PAUVRES D'URANIUM. EXTRACTION DE L'URANIUM DU PHOSPHATE TRICALCIQUE (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mechelynck, Ph.

1958-07-15

After an examination of the different processes for the treatment of uranium minerals, it is concluded that the extraction of uranium by ion exchange is not applicable to hydrochloric acid solutions of phosphates. A sulfuric or phosphoric solution can be used. For solvent extraction of uranium, sulfuric or phosphoric solutions are the best, but hydrochloric solutions can be used. The cost of the solvents used would determine the cost of the operation. It is necessary, in the case of liquid-liquid extraction, to filter or decant the solution before extraction. (tr-auth)

URANIUM RECOVERY PROCESS

DOEpatents

Kaufman, D.

1958-04-15

A process of recovering uranium from very low-grade ore residues is described. These low-grade uraniumcontaining hydroxide precipitates, which also contain hydrated silica and iron and aluminum hydroxides, are subjected to multiple leachings with aqueous solutions of sodium carbonate at a pH of at least 9. This leaching serves to selectively extract the uranium from the precipitate, but to leave the greater part of the silica, iron, and aluminum with the residue. The uranium is then separated from the leach liquor by the addition of an acid in sufficient amount to destroy the carbonate followed by the addition of ammonia to precipitate uranium as ammonium diuranate.

Application of LANDSAT satellite imagery for iron ore prospecting in the western desert of Egypt

NASA Technical Reports Server (NTRS)

Elshazly, E. M.; Abdel-Hady, M. A.; Elghawaby, M. A.; Khawasik, S. M. (Principal Investigator)

1977-01-01

The author has identified the following significant results. The delineation of the geological units and geological structures through image interpretation, corroborated by field observations and structural analysis, led to the discovery of new iron ore deposits. A new locality for iron ore deposition, namely Gebel Qalamun, was discovered, as well as new occurrences within the already known iron ore region of Bahariya Oasis.

Tourmaline as a recorder of ore-forming processes

USGS Publications Warehouse

Slack, John F.; Trumbull, Robert B.

2011-01-01

Tourmaline occurs in diverse types of hydrothermal mineral deposits and can be used to constrain the nature and evolution of ore-forming fl uids. Because of its broad range in composition and retention of chemical and isotopic signatures, tourmaline may be the only robust recorder of original mineralizing processes in some deposits. Microtextures and in situ analysis of compositional and isotopic variations in ore-related tourmaline provide valuable insights into hydrothermal systems in seafl oor, sedimentary, magmatic, and metamorphic environments. Deciphering the hydrothermal record in tourmaline also holds promise for aiding exploration programs in the search for new ore deposits.

Reactive flow models of the Anarraaq Zn-Pb-Ag deposit, Red Dog district, Alaska

USGS Publications Warehouse

Schardt, C.; Garven, G.; Kelley, K.D.; Leach, D.L.

2008-01-01

The Red Dog ore deposit district in the Brooks Range of northern Alaska is host to several high-grade, shale-hosted Zn + Pb deposits. Due to the complex history and deformation of these ore deposits, the geological and hydrological conditions at the time of formation are poorly understood. Using geological observations and fluid inclusion data as constraints, numerical heat and fluid flow simulations of the Anarraaq ore deposit environment and coupled reactive flow simulations of a section of the ore body were conducted to gain more insight into the conditions of ore body formation. Results suggest that the ore body and associated base metal zonation may have formed by the mixing of oxidized, saline, metal-bearing hydrothermal fluids (<200??C) with reducing, HS-rich pore fluids within radiolarite-rich host rocks. Sphalerite and galena concentrations and base metal sulfide distribution are primarily controlled by the nature of the pore fluids, i.e., the extent and duration of the HS- source. Forward modeling results also predict the distribution of pyrite and quartz in agreement with field observations and indicate a reaction front moving from the initial mixing interface into the radiolarite rocks. Heuristic mass calculations suggest that ore grades and base metal accumulation comparable to those found in the field (18% Zn, 5% Pb) are predicted to be reached after about 0.3 My for initial conditions (30 ppm Zn, 3 ppm Pb; 20% deposition efficiency). ?? Springer-Verlag 2008.

Geology of the manganese deposits of Cuba

USGS Publications Warehouse

Simons, Frank S.; Straczek, John A.

1958-01-01

Deposits of manganese ore have been found in five of the six provinces of Cuba and have been reported from the sixth.  Only Oriente and Pinar del Rio provinces have more than a few known deposits and only the deposits of Oriente have yielded any appreciable amount of ore.

U.S.-Australia Civilian Nuclear Cooperation: Issues for Congress

DTIC Science & Technology

2010-07-07

Mining and Milling ................................................................................................7 Uranium Sales to India...carried out at Lucas Heights (see below). The nuclear fuel cycle begins with mining uranium ore and upgrading it to yellowcake. Because naturally... mining and milling stage. Commercial enrichment services are available in the United States, Europe, Russia, and Japan. Fuel fabrication services are

Future Scenarios for Fission Based Reactors

NASA Astrophysics Data System (ADS)

David, S.

2005-04-01

The coming century will see the exhaustion of standard fossil fuels, coal, gas and oil, which today represent 75% of the world energy production. Moreover, their use will have caused large-scale emission of greenhouse gases (GEG), and induced global climate change. This problem is exacerbated by a growing world energy demand. In this context, nuclear power is the only GEG-free energy source available today capable of responding significantly to this demand. Some scenarios consider a nuclear energy production of around 5 Gtoe in 2050, wich would represent a 20% share of the world energy supply. Present reactors generate energy from the fission of U-235 and require around 200 tons of natural Uranium to produce 1GWe.y of energy, equivalent to the fission of one ton of fissile material. In a scenario of a significant increase in nuclear energy generation, these standard reactors will consume the whole of the world's estimated Uranium reserves in a few decades. However, natural Uranium or Thorium ore, wich are not themselves fissile, can produce a fissile material after a neutron capture ( 239Pu and 233U respectively). In a breeder reactor, the mass of fissile material remains constant, and the fertile ore is the only material to be consumed. In this case, only 1 ton of natural ore is needed to produce 1GWe.y. Thus, the breeding concept allows optimal use of fertile ore and development of sustainable nuclear energy production for several thousand years into the future. Different sustainable nuclear reactor concepts are studied in the international forum "generation IV". Different types of coolant (Na, Pb and He) are studied for fast breeder reactors based on the Uranium cycle. The thermal Thorium cycle requires the use of a liquid fuel, which can be reprocessed online in order to extract the neutron poisons. This paper presents these different sustainable reactors, based on the Uranium or Thorium fuel cycles and will compare the different options in term of fissile inventory, capacity to be deployed, induced radiotoxicities, and R&D efforts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuzmina, L.A.

A method has been developed for determining uranium, thorium, and ionium (Th/sup 230/) in sea silt from a single sample. The completeness of isolation and radiochemical purity of thorium isotopes have been tested by means of tracers. The method has been proved on samples of sea silt as well as of rocks, ores, and minerals. It is applicable at thorium content from 5 x 10/sup -5/ to x x 10/sup - 4/% when uranium content is x x 10/sup -4/ % and at uranium content up to 70% when ionium contert is x x 10/sup -4/% (uranium equivalent). (tr-auth)

Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran) using REE geochemistry

NASA Astrophysics Data System (ADS)

Mokhtari, Mir Ali Asghar; Zadeh, Ghader Hossein; Emami, Mohamad Hashem

2013-06-01

Rare earth elements in apatites of different ore types show characteristic patterns which are related to different modes of formation of the ores. Most of the apatite-bearing iron ores are associated with alkaline magmas with LREE/HREE fractionation varying from moderate to steep. Iron-apatite deposits in Posht-e-Badam Block (Central Iran) have a high concentration of REE (more than 1000 ppm up to 2.5%), and show a strong LREE/HREE ratio with a pronounced negative Eu anomaly. This REE pattern is typical of magmatic apatite and quiet distinct from sedimentary apatites (phosphorites) which have a low REE contents and Ce negative anomalies. On the other hand, they are comparable to the REE patterns of apatites in Kiruna-type iron ores in different parts of the world. The REE patterns of apatites, iron-apatite ores and iron ores are similar and only have different REE contents. This similarity indicates a genetic relation for these rocks. Most of the iron-apatite deposits in Central Iran have similar REE patterns too, which in turn show a genetic relation for all of these deposits. This similarity indicates a similar origin and processes in their genesis. There are some small intrusions around some of the iron-apatite deposits that are petrographically identified as syenite and gabbro. These intrusions also have REE patterns similar to that of iron-apatite ores. This demonstrates a genetic relation between these intrusions and iron-apatite ores. The REE patterns of apatites in different deposits of Posht-e-Badam Block iron-apatite ores show an affinity to alkaline to sub-alkaline magmas and rifting environment. The alkaline host rocks of Central Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE-NNW fault lines). A probable source for this large scale ore forming processes is relatively low partial melting of mantle rocks. The ores have originated by magmatic differentiation as a late phase in the volcanic cycle forming sub-surface injections or surface flows. These ores have formed during magmatism as immiscible liquids (silicate and Fe-P-rich magmatic liquids) which separated from strongly differentiated magmas aided by a large volatile and alkali element content. Separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits. We proposed that the separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits.

Mineral transformations during the dissolution of uranium ore minerals by dissimilatory metal-reducing bacteria

NASA Astrophysics Data System (ADS)

Glasauer, S.; Weidler, P.; Fakra, S.; Tyliszczak, T.; Shuh, D.

2011-12-01

Carnotite minerals [X2(UO2)2(VO4)2]; X = K, Ca, Ba, Mn, Na, Cu or Pb] form the major ore of uranium in the Colorado Plateau. These deposits are highly oxidized and contain U(VI) and V(IV). The biotransformation of U(VI) bound in carnotite by bacteria during dissimilatory metal reduction presents a complex puzzle in mineral chemistry. Both U(VI) and V(V) can be respired by metal reducing bacteria, and the mineral structure can change depending on the associated counterion. We incubated anaerobic cultures of S. putrefaciens CN32 with natural carnotite minerals from southeastern Utah in a nutrient-limited defined medium. Strain CN32 is a gram negative bacterium and a terrestrial isolate from New Mexico. The mineral and metal transformations were compared to a system that contained similar concentrations of soluble U(VI) and V(V). Electron (SEM, TEM) microscopies and x-ray spectromicroscopy (STXM) were used in conjunction with XRD to track mineral changes, and bacterial survival was monitored throughout the incubations. Slow rates of metal reduction over 10 months for the treatment with carnotite minerals revealed distinct biotic and abiotic processes, providing insight on mineral transformation and bacteria-metal interactions. The bacteria existed as small flocs or individual cells attached to the mineral phase, but did not adsorb soluble U or V, and accumulated very little of the biominerals. Reduction of mineral V(V) necessarily led to a dismantling of the carnotite structure. Bioreduction of V(V) by CN32 contributed small but profound changes to the mineral system, resulting in new minerals. Abiotic cation exchange within the carnotite group minerals induced the rearrangement of the mineral structures, leading to further mineral transformation. In contrast, bacteria survival was poor for treatments with soluble U(VI) and V(V), although both metals were reduced completely and formed solid UO2 and VO2; we also detected V(III). For these treatments, the bacteria formed extensive biofilms or flocs that contained U and V in the exopolymer, but excluded these metals from the bacteria. This suggests a specific mechanism to inhibit metal sorption to cell wall components. The example illustrates the interplay between bacteria and minerals under conditions that model oligotrophic survival, and provides insight on U mobilization from common uranium ore minerals.

Rational design of bottom blocks for development of ore deposits systems with caving of ore and enclosing rocks

NASA Astrophysics Data System (ADS)

Versilov, S. O.; Posylniy, Yu V.; Shurygin, D. N.; Tretyak, A. Ya

2017-10-01

The assessment of the geological conditions of development of existing ore deposits was made. For testing ore deposits in difficult mining and geological conditions, the authors proposed the system of development, accompanied by collapse of the mechanical ore with the use of feeders of active action that could be manufactured directly in the mine in accordance with the specific conditions of occurrence of minerals. The paper demonstrates the technology of manufacture of load-bearing structures of the feeder directly in the mine at the scene of the breaking of the first layer of ore, as well as the dynamics of the ore and the choice of parameters of concrete feeders. A new design of the bottom block was proposed, the idea of technical solution of which consists in the fact that it is offered to undergo the production of the smallest possible cross section, which is determined only by the dimensions of the conveyors to deliver ore. And before the explosion of fans of production wells, it is necessary to produce local collapse of the roof production to increase its height at the place of production of ore by blasting wellheads in two or three rows.

First-Principles Integrated Adsorption Modeling for Selective Capture of Uranium from Seawater by Polyamidoxime Sorbent Materials

DOE PAGES

Ladshaw, Austin P.; Ivanov, Alexander S.; Das, Sadananda; ...

2018-03-27

Nuclear power is a relatively carbon-free energy source that has the capacity to be utilized today in an effort to stem the tides of global warming. The growing demand for nuclear energy, however, could put significant strain on our uranium ore resources, and the mining activities utilized to extract that ore can leave behind long-term environmental damage. A potential solution to enhance the supply of uranium fuel is to recover uranium from seawater using amidoximated adsorbent fibers. This technology has been studied for decades but is currently plagued by the material’s relatively poor selectivity of uranium over its main competitormore » vanadium. In this work, we investigate the binding schemes between uranium, vanadium, and the amidoxime functional groups on the adsorbent surface. Using quantum chemical methods, binding strengths are approximated for a set of complexation reactions between uranium and vanadium with amidoxime functionalities. Those approximations are then coupled with a comprehensive aqueous adsorption model developed in this work to simulate the adsorption of uranium and vanadium under laboratory conditions. Experimental adsorption studies with uranium and vanadium over a wide pH range are performed, and the data collected are compared against simulation results to validate the model. It was found that coupling ab initio calculations with process level adsorption modeling provides accurate predictions of the adsorption capacity and selectivity of the sorbent materials. Furthermore, this work demonstrates that this multiscale modeling paradigm could be utilized to aid in the selection of superior ligands or ligand compositions for the selective capture of metal ions. Furthermore, this first-principles integrated modeling approach opens the door to the in silico design of next-generation adsorbents with potentially superior efficiency and selectivity for uranium over vanadium in seawater.« less

First-Principles Integrated Adsorption Modeling for Selective Capture of Uranium from Seawater by Polyamidoxime Sorbent Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ladshaw, Austin P.; Ivanov, Alexander S.; Das, Sadananda

Nuclear power is a relatively carbon-free energy source that has the capacity to be utilized today in an effort to stem the tides of global warming. The growing demand for nuclear energy, however, could put significant strain on our uranium ore resources, and the mining activities utilized to extract that ore can leave behind long-term environmental damage. A potential solution to enhance the supply of uranium fuel is to recover uranium from seawater using amidoximated adsorbent fibers. This technology has been studied for decades but is currently plagued by the material’s relatively poor selectivity of uranium over its main competitormore » vanadium. In this work, we investigate the binding schemes between uranium, vanadium, and the amidoxime functional groups on the adsorbent surface. Using quantum chemical methods, binding strengths are approximated for a set of complexation reactions between uranium and vanadium with amidoxime functionalities. Those approximations are then coupled with a comprehensive aqueous adsorption model developed in this work to simulate the adsorption of uranium and vanadium under laboratory conditions. Experimental adsorption studies with uranium and vanadium over a wide pH range are performed, and the data collected are compared against simulation results to validate the model. It was found that coupling ab initio calculations with process level adsorption modeling provides accurate predictions of the adsorption capacity and selectivity of the sorbent materials. Furthermore, this work demonstrates that this multiscale modeling paradigm could be utilized to aid in the selection of superior ligands or ligand compositions for the selective capture of metal ions. Furthermore, this first-principles integrated modeling approach opens the door to the in silico design of next-generation adsorbents with potentially superior efficiency and selectivity for uranium over vanadium in seawater.« less

First-Principles Integrated Adsorption Modeling for Selective Capture of Uranium from Seawater by Polyamidoxime Sorbent Materials.

PubMed

Ladshaw, Austin P; Ivanov, Alexander S; Das, Sadananda; Bryantsev, Vyacheslav S; Tsouris, Costas; Yiacoumi, Sotira

2018-04-18

Nuclear power is a relatively carbon-free energy source that has the capacity to be utilized today in an effort to stem the tides of global warming. The growing demand for nuclear energy, however, could put significant strain on our uranium ore resources, and the mining activities utilized to extract that ore can leave behind long-term environmental damage. A potential solution to enhance the supply of uranium fuel is to recover uranium from seawater using amidoximated adsorbent fibers. This technology has been studied for decades but is currently plagued by the material's relatively poor selectivity of uranium over its main competitor vanadium. In this work, we investigate the binding schemes between uranium, vanadium, and the amidoxime functional groups on the adsorbent surface. Using quantum chemical methods, binding strengths are approximated for a set of complexation reactions between uranium and vanadium with amidoxime functionalities. Those approximations are then coupled with a comprehensive aqueous adsorption model developed in this work to simulate the adsorption of uranium and vanadium under laboratory conditions. Experimental adsorption studies with uranium and vanadium over a wide pH range are performed, and the data collected are compared against simulation results to validate the model. It was found that coupling ab initio calculations with process level adsorption modeling provides accurate predictions of the adsorption capacity and selectivity of the sorbent materials. Furthermore, this work demonstrates that this multiscale modeling paradigm could be utilized to aid in the selection of superior ligands or ligand compositions for the selective capture of metal ions. Therefore, this first-principles integrated modeling approach opens the door to the in silico design of next-generation adsorbents with potentially superior efficiency and selectivity for uranium over vanadium in seawater.

Internal structures and dating of non-sulphide Zn deposits using rock magnetism: insights from the Moroccan High Atlas

NASA Astrophysics Data System (ADS)

Charles, Nicolas; Choulet, Flavien; Sizaret, Stanislas; Chen, Yan; Barbanson, Luc; Ennaciri, Aomar; Badra, Lakhlifi; Branquet, Yannick

2016-01-01

The renewal of interest in Zn-Pb non-sulphide ores has been induced by mineral processing improvement and leads to new exploration and mining projects in the world. Although the mineralogy is often precisely known, and despite several studies linking ore deposition to regional tectonics, absolute dating of non-sulphide stages is rare and structure of ore bodies was largely disregarded. Geochronological data from non-sulphide ores are essential to timely constrain alteration episodes and to insert supergene ore genesis in the climate and tectonic evolution of the metallogenic province. The access to internal organization of ore could reveal post-mineralization episodes related to supergene evolution. Thus, a rock magnetism study combining anisotropy of magnetic susceptibility (AMS) and palaeomagnetism was performed on four non-sulphide deposits from the Moroccan High Atlas. AMS generally shows similar horizontal magnetic fabrics for ores and the clayey and carbonaceous internal sediments filling karstic cavities. The palaeomagnetic directions of ores and internal sediments are compatible, and the calculated poles are consistent with the last 30 Ma of the Africa apparent polar wander path, with an upper age at 0.78 Ma. The proposed three-step scenario is placed within the evolution of the Moroccan High Atlas belt. Deposition of primary sulphides is contemporaneous with opening of the Tethyan and Atlantic oceans. During the Tertiary, intracontinental deformation gave rise to the High Atlas fold-and-thrust belt and to regional uplift. Finally, Zn-Pb sulphides hosted in carbonates experienced oxidation under an arid climate to form karst-related Zn-Pb non-sulphide ores. These promising results pave the way for an efficient method to constrain the internal fabrics and age of Zn supergene deposits.

Evolution of volcanic and tectonic features in caldera settings and their importance in the localization of ore deposits

USGS Publications Warehouse

Rytuba, J.J.

1994-01-01

Many calderas are located along regionally important fault zones that are intermittently active before and after the caldera cycle. In mineralized calderas, the ore deposits are controlled by structures developed during caldera formation and by regional faults which intersect and reactivate the caldera-related structures. The paper discusses the importance of the different stages of caldera formation in connection with the localization of ore deposits. -from Author

Genesis of copper-lead mineralization in the regionally zoned Agnigundala Sulfide Belt, Cuddapah Basin, Andhra Pradesh, India

NASA Astrophysics Data System (ADS)

Bhattacharya, H. N.; Bandyopadhyay, Sandip

2018-03-01

Shallow marine sandstone-shale-carbonate sedimentary rocks of the Paleoproterozoic northern Cuddapah basin host copper (Nallakonda deposit), copper-lead (Dhukonda deposit), and lead mineralization (Bandalamottu deposit) which together constitute the Agnigundala Sulfide Belt. The Cu sulfide mineralization in sandstone is both stratabound and disseminated, and Pb sulfide mineralization occurs as stratabound fracture filling veins and/or replacement veins within dolomite. Systematic mineralogical and sulfur, carbon, and oxygen isotope studies of the three deposits indicate a common ore-fluid that deposited copper at Nallakonda, copper-lead at Dhukonda, and lead at Bandalamottu under progressive cooling during migration through sediments. The ore-fluid was of low temperature (< 200 °C) and oxidized. Thermochemical reduction of basinal water sulfate produced sulfide for ore deposition. It is envisaged that basal red-bed and evaporite-bearing rift-related continental to shallow marine sediments might have acted as the source for the metals. Rift-related faults developed during sedimentation in the basin might have punctured the ore-fluid pool in the lower sedimentary succession and also acted as conduits for their upward migration. The ore-bearing horizons have participated in deformations during basin inversion without any recognizable remobilization.

A combined chemical, isotopic and microstructural study of pyrite from roll-front uranium deposits, Lake Eyre Basin, South Australia

NASA Astrophysics Data System (ADS)

Ingham, Edwina S.; Cook, Nigel J.; Cliff, John; Ciobanu, Cristiana L.; Huddleston, Adam

2014-01-01

The common sulfide mineral pyrite is abundant throughout sedimentary uranium systems at Pepegoona, Pepegoona West and Pannikan, Lake Eyre Basin, South Australia. Combined chemical, isotopic and microstructural analysis of pyrite indicates variation in fluid composition, sulfur source and precipitation conditions during a protracted mineralization event. The results show the significant role played by pyrite as a metal scavenger and monitor of fluid changes in low-temperature hydrothermal systems. In-situ micrometer-scale sulfur isotope analyses of pyrite demonstrated broad-scale isotopic heterogeneity (δ34S = -43.9 to +32.4‰VCDT), indicative of complex, multi-faceted pyrite evolution, and sulfur derived from more than a single source. Preserved textures support this assertion and indicate a genetic model involving more than one phase of pyrite formation. Authigenic pyrite underwent prolonged evolution and recrystallization, evidenced by a genetic relationship between archetypal framboidal aggregates and pyrite euhedra. Secondary hydrothermal pyrite commonly displays hyper-enrichment of several trace elements (Mn, Co, Ni, As, Se, Mo, Sb, W and Tl) in ore-bearing horizons. Hydrothermal fluids of magmatic and meteoric origins supplied metals to the system but the geochemical signature of pyrite suggests a dominantly granitic source and also the influence of mafic rock types. Irregular variation in δ34S, coupled with oscillatory trace element zonation in secondary pyrite, is interpreted in terms of continuous variations in fluid composition and cycles of diagenetic recrystallization. A late-stage oxidizing fluid may have mobilized selenium from pre-existing pyrite. Subsequent restoration of reduced conditions within the aquifer caused ongoing pyrite re-crystallization and precipitation of selenium as native selenium. These results provide the first qualitative constraints on the formation mechanisms of the uranium deposits at Beverley North. Insights into depositional conditions and sources of both sulfide and uranium mineralization and an improved understanding of pyrite geochemistry can also underpin an effective vector for uranium exploration at Beverley North and other sedimentary systems of the Lake Eyre Basin, as well as in comparable geological environments elsewhere. Average intensity of 32S signal in counts per second × 108.Drift corrected 34S/32S prior to IMF calibration.Two-sigma propagated uncertainty on individual measurements.

Remote Sensing Detecting for Hydrocarbon Microseepage and Relationship with the Uranium Mineralization in Dongsheng Area, Ordos Basin, China

NASA Astrophysics Data System (ADS)

Zhu, M.; Liu, D.; Gao, Y.

2005-12-01

The Ordos Basin is located at the central area of northern China with an area of about 250,000 km2. It is well known "a basin of energy resources" of China for its large reserves of coal, oil and gas. A large-scale sandstone-type uranium metallogenic belt has been found recently in Zhiluo Formation of middle Jurassic in Dongsheng area in the northeastern part of the basin. The ore-forming mechanism remains unsolved so far. There is a hypothesis that the uranium precipitation was related to a hydrocarbon migration from the central basin. In order to explore the evidences of ever existed hydrocarbon microseepage and migration in this area, several indices such as the Iron Oxide Index, Ferrous Index, Clay Mineral Index, Mineral Composite Index, and Ferrous Transfer Percentage Index have been derived. Thorium Normalization of aeroradiometric data and fusion of aeroradiometric and TM data have been carried out as well. Therefore, the subaerial oxide and reduced area, uranium outmigrated and immigrated area, and ancient recharge and discharge of groundwater are thus delineated. As a result, two hydrocarbon microseepage belts in Dongsheng area have been extracted by combining the methods mentioned above. One is in the northern of Dongsheng along a nearly east-westward fault zone and the other one is in the southern of Dongsheng uranium mineralization belt along a nearly northwestward fault zone. The study suggests that the subaerial reduced area was related to hydrocarbon microseepage and the hydrocarbon migration along the fault and fracture zone or penetrable strata played an important role for uranium deposition in Zhiluo Formation near the northwestward fault zone.

Copper Deposits in Sedimentary and Volcanogenic Rocks

USGS Publications Warehouse

Tourtelot, Elizabeth B.; Vine, James David

1976-01-01

Copper deposits occur in sedimentary and volcanogenic rocks within a wide variety of geologic environments where there may be little or no evidence of hydrothermal alteration. Some deposits may be hypogene and have a deep-seated source for the ore fluids, but because of rapid cooling and dilution during syngenetic deposition on the ocean floor, the resulting deposits are not associated with hydrothermal alteration. Many of these deposits are formed at or near major tectonic features on the Earth's crust, including plate boundaries, rift valleys, and island arcs. The resulting ore bodies may be stratabound and either massive or disseminated. Other deposits form in rocks deposited in shallow-marine, deltaic, and nonmarine environments by the movement and reaction of interstratal brines whose metal content is derived from buried sedimentary and volcanic rocks. Some of the world's largest copper deposits were probably formed in this manner. This process we regard as diagenetic, but some would regard it as syngenetic, if the ore metals are derived from disseminated metal in the host-rock sequence, and others would regard the process as epigenetic, if there is demonstrable evidence of ore cutting across bedding. Because the oxidation associated with diagenetic red beds releases copper to ground-water solutions, red rocks and copper deposits are commonly associated. However, the ultimate size, shape, and mineral zoning of a deposit result from local conditions at the site of deposition - a logjam in fluvial channel sandstone may result in an irregular tabular body of limited size; a petroleum-water interface in an oil pool may result in a copper deposit limited by the size and shape of the petroleum reservoir; a persistent thin bed of black shale may result in a copper deposit the size and shape of that single bed. The process of supergene enrichment has been largely overlooked in descriptions of copper deposits in sedimentary rocks. However, supergene processes may be involved during erosion of any primary ore body and its ultimate displacement and redeposition as a secondary deposit. Bleached sandstone at the surface may indicate significant ore deposits near the water table.

Mineralogy and fluid inclusions study of carbonate-hosted Mississippi valley-type Ain Allega Pb-Zn-Sr-Ba ore deposit, Northern Tunisia

NASA Astrophysics Data System (ADS)

Abidi, R.; Slim-Shimi, N.; Somarin, A.; Henchiri, M.

2010-05-01

The Ain Allega Pb-Zn-Sr-Ba ore deposit is located in the flysch zone on the Eastern edge of the Triassic diapir of Jebel Hamra. It is part of the extrusive Triassic evaporate formation along the Ghardimaou-Cape Serrat faults. The ore body consists of argilic-dolomite breccias surrounded by argilo-gypsum Triassic formation, which forms the hanging wall of the deposit, and rimmed by the Paleocene marls. The ore minerals show a cap-rock type mineralization with different styles particularly impregnation in dolomite, cement of breccias, replacement ore and open space filling in the dissolution cavities and fractures. Ore minerals include sphalerite, galena, marcasite and pyrite. Principal gangue minerals are composed of barite, celestite, calcite, dolomite and quartz. The ore minerals are hosted by the Triassic carbonate rocks which show hydrothermal alteration, dissolution and brecciation. X-ray - crystallographic study of barite-celestite mineral series shows that pure barite and celestite are the abundant species, whereas strontianiferous barite (85-96.5% BaSO 4) and barian-celestite (95% SrSO 4) are minor. Primary and secondary mono-phase (liquid only) fluid inclusions are common in celestite. Microthermometric analyses in two-phases (liquid and vapour) fluid inclusions suggest that gangue and ore minerals were precipitated by a low-temperature (180 °C) saline (16.37 wt.% NaCl equivalent) solution originated possibly from a basinal brine with some input from magmatic or metamorphic fluid. Based on geology, mineralogy, texture and fluid characteristics, the Ain Allega deposit is classified as a carbonate-hosted Mississippi valley-type deposit.

Margaritasite: a new mineral of hydrothermal origin from the Pena Blanca uranium district, Mexico.

USGS Publications Warehouse

Wenrich, K.J.; Modreski, P.J.; Zielinski, R.A.; Seeley, J.L.

1982-01-01

Margaritasite, (Cs,K,H3O)2(UO2)2V2O8.nH2O (where Cs > K, H3O and n approx 1), a 10.514, b 8.425, c 7.25 A, beta 106.01o, P21/a, Z = 2, is a newly recognized uranium ore mineral named for the Margaritas deposit, Pena Blanca uranium district, Chihuahua, Mexico, at which it was discovered. A Cs-rich analogue of carnotite, margaritasite is the natural equivalent of synthetic Cs-uranyl vanadate (A.M. 43- 799, 50-825). A fine-grained yellow mineral, it is most easily distinguished from carnotite by XRD; X-ray powder patterns (CuKalpha radiation) show that the (001) reflection of margaritasite lies at 12.7o (2theta ), while that of carnotite is found at 13.8o (2theta ). The shift of the (001) reflection in margaritasite reflects the structural changes caused when Cs occupies the sites filled by K in carnotite. Synthesis experiments indicate that margaritasite also differs from carnotite in a higher-T hydrothermal origin. Chemical analyses and XRD data for margaritasite and synthetic Cs- carnotite, and chemical analyses for rocks from Sierra Pena Blanca and vicinity, are tabulated.-J.A.Z.

Determination of the elemental concentration of uranium and thorium in the products and by-products of amang tin tailings process

NASA Astrophysics Data System (ADS)

Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Hamzah, S.; Elias, M. S.

2017-01-01

Amang or tin tailing is processed into concentrated ores and other economical valuable minerals such as monazite, zircon, xenotime, ilmenite etc. Besides that, the tailings from these ores may have a significant potential source of radiation exposure to amang plants' workers. This study was conducted to determine the elemental concentration of uranium and thorium in mineral samples collected from five amang tailing factories. The concentration of uranium and thorium was carried out by using instrumental neutron activation analysis (INAA) relative technique. The concentration of uranium and thorium in ppm obtained in this study are as follows: raw (189-1064) and (622-4965); monazite (1076-1988) and (3467-33578); xenotime 4053 and 5540; zircon (309-3090) and (387-6339); ilmenite (104-583) and (88-1205); rutile (212-889) and (44-1119); pyrite (7-43) and (9-132); and waste (5-338) and (9-1218) respectively. The analysis results shows that the monazite, xenotime and zircon have high content of uranium and thorium, whereas ilmenite, rutile, pyrite and waste have lower concentration compare with raw materials after tailing process. The highest values of uranium and thorium concentrations (4053 ± 428 ppm and 33578 ± 873 ppm, respectively) were observed in xenotime and monazite; whereas the lowest value was 5.48 ± 0.86 ppm of uranium recorded in waste (sand) and 9 ± 0.32 ppm of thorium for waste (sand) and pyrite.

Sedimentary carbonate-hosted giant Bayan Obo REE-Fe-Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin

USGS Publications Warehouse

Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Tatsumoto, M.; Junwen, Wang; Conrad, J.E.; McKee, E.H.; Zonglin, Hou; Qingrun, Meng; Shengguang, Huang

1997-01-01

Detailed, integrative field and laboratory studies of the textures, structures, chemical characteristics, and isotopically determined ages and signatures of mineralization of the Bayan Obo deposit provided evidence for the origin and characteristics favorable for its formation and parameters necessary for defining giant polymetallic deposits of hydrothermal origin. Bayan Obo is an epigenetic, metasomatic, hydrothermal rare earth element (REE)-Fe-Nb ore deposit that is hosted in the metasedimentary H8 dolostone marble of the Middle Proterozoic Bayan Obo Group. The metasedimentary sequence was deposited on the northern continental slope of the North China craton. The mine area is about 100 km south of the suture marking Caledonian subduction of the Mongolian oceanic plate from the north beneath the North China craton. The mineralogy of the deposit is very complex, consisting of more than 120 different minerals, some of which are epigenetic minerals introduced by hydrothermal solutions, and some of which are primary and secondary metamorphic minerals. The major REE minerals are monazite and bastnaesite, whereas magnetite and hematite are the dominant Fe-ore minerals, and columbite is the most abundant Nb mineral. Dolomite, alkali amphibole, fluorite, barite, aegirine augite, apatite, phlogopite, albite, and microcline are the most widespread gangue minerals. Three general types of ores occur at Bayan Obo: disseminated, banded, and massive ores. Broad zoning of these ore types occurs in the Main and East Orebodies. Disseminated ores are in the outermost zone, banded ores are in the intermediate zone, and massive ores are in the cores of the orebodies. On the basis of field relations, host rocks, textures, structures, and mineral assemblages, many varieties of these three types of ores have been recognized and mapped. Isotopic dating of monazite, bastnaesite, aeschynite, and metamorphic and metasomatic alkali amphiboles associated with the deposit provides constraints on the ages of mineralization and the history of the deposit. Textural relations, differences in chemical composition, and 232Th/208Pb internal isochron ages of monazite and bastnaesite samples indicate that many episodes of REE mineralization occurred at Bayan Obo, ranging from about 555 Ma to about 398 Ma. Initial 208Pb/204Pb ratios suggest different sources of REE's for different generations of REE minerals. Relative ages of Fe mineralization were deduced from textural relationships of Fe minerals with other, dated mineral phases in the deposit. Most Nb mineralization was in the area of the West Orebodies and resulted in disseminated ore. Aeschynite, an early stage of Nb mineralization (438+-25.1 Ma), occurs with huanghoite and alkali amphiboles in veins. The 40Ar/39Ar ages of amphiboles, as well as petrographic textures, were used to distinguish three periods of regional metamorphism in the Bayan Obo mine area: (1) Late Proterozoic, about 890 Ma, which recrystallized H8 carbonate to marble and crystallized lineated alkali amphiboles along foliation planes in the marble; (2) Caledonian, about 425-395 Ma, which resulted in metamorphic and metasomatic-metamorphic alkali amphiboles; and (3) Hercynian, about 300 Ma, based on biotite 40Ar/39Ar analyses from biotite schist and folded banded ores. The 40Ar/39Ar ages of metasomatic alkali amphiboles also place time constraints on the hydrothermal history of the ore deposit. Metasomatic amphiboles represent periods of intense hydrothermal activity, which began as early as 1.26 Ga; that date is based on the age of amphibole from a vein that crosscuts the H6 quartzite that underlies the H8 dolostone marble. Although much of the metasomatic amphibole formed during periods that overlapped the peak period of REE mineralization of banded ores, REE and alkali amphibole phases generally occur in different mineral assemblages or are of very different ages in the same assemblage and, therefore, may have been derived from

Structural evolution of the Mount Wall region in the Hamersley province, Western Australia and its control on hydrothermal alteration and formation of high-grade iron deposits

NASA Astrophysics Data System (ADS)

Dalstra, Hilke J.

2014-10-01

The discovery of two relatively small but high-grade iron ore deposits near Mt Wall, an intensely faulted part of the southwestern Hamersley province provides unique insights into the structural control on ore formation in this region. The deposits have many geological features typical of the high grade microplaty hematite group which also contains the much larger Mt Tom Price, Paraburdoo and Mt Whaleback deposits. The deposits are structurally controlled along early normal faults and contain abundant microplaty hematite and martite, and are largely confined to the Dales Gorge member of the Brockman Iron Formation. In addition to the microplaty hematite-martite ore, there are martite-goethite ores and rare magnetite-goethite or magnetite-hematite ores. Below the modern weathering surface, hydrothermally altered zones in wallrock BIF from the Lower Dales Gorge member contain magnetite, hematite and carbonate/talc bearing mineral assemblages. A staged ore genesis model involving early extension and fluid circulation along normal faults, hypogene silica leaching and carbonate alteration, followed by deep meteoric oxidation with microplaty hematite formation and finally weathering can explain most features of the Mt Wall deposits. The role of deformation was to provide pathways for mineralising fluids and initiate the seed points for the mineralised systems. High grade iron in the Wellthandalthaluna deposit is situated between the NW to NNW trending Boolgeeda Creek fault and a synthetic joining splay, the Northern fault. Both are high angle normal faults and formed during early extension in this part of the province. Faults are characterised by localised small scale deformation and brecciation, deep carbonate alteration and oxidation. Recent weathering has penetrated deeply into the fault zones, converting the carbonate-rich assemblages into goethite. Mineralisation in the Arochar deposit is situated in the overlap or relay zone between two segments of the Mt Wall fault zone, a moderately to steeply southerly dipping normal fault system which at Arochar is intruded by dolerite dykes. At both locations, the ore controlling faults are offset by later NW trending dextral and normal faults. Fault relay zones or fault splay zones were likely zones of increased permeability and fluid flow during fault development or reactivation and may also have been important in initiating mineralisation in larger deposits such as Mt Tom Price and Mt Whaleback. However structural controls on the largest iron ore deposits are often obscured due to the intensity and scale of ore development, whereas they are better preserved in the smaller deposits. Recognition that carbonate bearing protores at Mt Wall survived for nearly two billion years until intense recent weathering converted them to martite-goethite or magnetite-goethite ores may imply that more of the giant hematite-goethite deposits of the Hamersley province had hydrothermal precursors and were not formed by supergene processes alone.

Geochemical Peculiarities of Galena and Sphalerite from Polymetallic Deposits of the Dal'negorskii Ore Region (Primorsky Krai, Russia)

NASA Astrophysics Data System (ADS)

Rogulina, L. I.; Moiseenko, V. G.; Ponomarchuk, V. A.

2018-04-01

New data on the composition of the major minerals from the skarn and vein polymetallic deposits of the Dal'negorskii ore region are reported. Analysis of galena and sphalerite was carried out by the X-ray fluorescent energy-dispersive method of synchrotron radiation for the first time. It is shown that the minor elements in major minerals of different deposits are typomorphic. Among these elements are Fe, Cu, Ni, Cd, Ag, Sn, and Sb, as well as In in sphalerite and Te in galena. The high concentrations of Ag, Cu, Te, Cd, and In in the extracted minerals indicate the complex character of mineralization. The compositional patterns of ore minerals characterize the sequence of mineral formation from the skarn to vein ores, and the sequence of deposits from the mesothermal to epithermal conditions. This provides geochemical evidence for the stage model of the formation of mineralization in the Dal'negorskii ore region.

Mercury from mineral deposits and potential environmental impact

USGS Publications Warehouse

Rytuba, J.J.

2003-01-01

Mercury deposits are globally distributed in 26 mercury mineral belts. Three types of mercury deposits occur in these belts: silica-carbonate, hot-spring, and Almaden. Mercury is also produced as a by-product from several types of gold-silver and massive sulfide deposits, which account for 5% of the world's production. Other types of mineral deposits can be enriched in mercury and mercury phases present are dependent on deposit type. During processing of mercury ores, secondary mercury phases form and accumulate in mine wastes. These phases are more soluble than cinnabar, the primary ore mineral, and cause mercury deposits to impact the environment more so than other types of ore deposits enriched in mercury. Release and transport of mercury from mine wastes occur primarily as mercury-enriched particles and colloids. Production from mercury deposits has decreased because of environmental concerns, but by-product production from other mercury-enriched mineral deposits remains important.

Geochemical contrasts between Late Triassic ore-bearing and barren intrusions in the Weibao Cu-Pb-Zn deposit, East Kunlun Mountains, NW China: constraints from accessory minerals (zircon and apatite)

NASA Astrophysics Data System (ADS)

Zhong, Shihua; Feng, Chengyou; Seltmann, Reimar; Li, Daxin; Dai, Zhihui

2017-12-01

The Weibao copper-lead-zinc skarn deposit is located in the northern East Kunlun terrane, NW China. Igneous intrusions in this deposit consist of barren diorite porphyry (U-Pb zircon age of 232.0 ± 2.0 Ma) and ore-bearing quartz diorite and pyroxene diorite (U-Pb zircon ages of 223.3 ± 1.5 and 224.6 ± 2.9 Ma, respectively). Whole-rock major and trace element and accessory mineral (zircon and apatite) composition from these intrusions are studied to examine the different geochemical characteristics of ore-bearing and barren intrusions. Compared to the barren diorite porphyry, the ore-bearing intrusions have higher Ce4+/Ce3+ ratios of zircon and lower Mn contents of apatite, indicating higher oxidation state. Besides, apatite from the ore-bearing intrusions shows higher Cl contents and lower F/Cl ratios. These characteristics collectively suggest the higher productivity of ore-bearing quartz diorite and pyroxene diorite. When compared with ore-bearing intrusions from global porphyry Cu deposits, those from Cu-Pb-Zn skarn deposits display lower Ce4+/Ce3+ and EuN/EuN* ratios of zircon and lower Cl and higher F/Cl ratios of apatite. We conclude that these differences reflect a general geochemical feature, and that zircon and apatite composition is a sensitive tool to infer economic potential of magmas and the resulting mineralization types in intrusion-related exploration targets.

Ore-fluid evolution at the Getchell Carlin-type gold deposit, Nevada, USA

USGS Publications Warehouse

Cline, J.S.; Hofstra, A.A.

2000-01-01

Minerals and fluid-inclusion populations were examined using petrography, microthermometry, quadrupole mass-spectrometer gas analyses and stable-isotope studies to characterize fluids responsible for gold mineralization at the Getchell Carlin-type gold deposit. The gold-ore assemblage at Getchell is superimposed on quartz-pyrite vein mineralization associated with a Late-Cretaceous granodiorite stock that intruded Lower-Paleozoic sedimentary rocks. The ore assemblage, of mid-Tertiary age, consists of disseminated arsenian pyrite that contains submicrometer gold, jasperoid quartz, and later fluorite and orpiment that fill fractures and vugs. Late ore-stage realgar and calcite enclose ore-stage minerals. Pre-ore quartz trapped fluids with a wide range of salinities (1 to 21 wt.% NaCl equivalent), gas compositions (H2O, CO2, and CH4), and temperatures (120 to >360??C). Oxygen- and hydrogen-isotope ratios indicate that pre-ore fluids likely had a magmatic source, and were associated with intrusion of the granodiorite stock and related dikes. Ore-stage jasperoid contains moderate salinity, aqueous fluid inclusions trapped at 180 to 220??C. Ore fluids contain minor CO2 and trace H2S that allowed the fluid to react with limestone host rocks and transport gold, respectively. Aqueous inclusions in fluorite indicate that fluid temperatures declined to ~175??C by the end of ore-stage mineralization. As the hydrothermal system collapsed, fluid temperatures declined to 155 to 115??C and realgar and calcite precipitated. Inclusion fluids in ore-stage minerals have high ??D(H2O) and ??18O(H2O) values that indicate that the fluid had a deep source, and had a metamorphic or magmatic origin, or both. Late ore-stage fluids extend to lower ??D(H2O) values, and have a wider range of ??18O(H2O) values suggesting dilution by variably exchanged meteoric waters. Results show that deeply sourced ore fluids rose along the Getchell fault system, where they dissolved carbonate wall rocks and deposited gold-enriched pyrite and jasperoid quartz. Gold and pyrite precipitated together as H2S in the ore fluids reacted with iron in the host rocks. As ore fluids mixed with local aquifer fluids, ore fluids became cooler and more dilute. Cooling caused precipitation of ore-stage fluorite and orpiment, and late ore-stage realgar. Phase separation and/or neutralization of the ore fluid during the waning stages of the hydrothermal ore system led to deposition of late ore-stage calcite.

ISOTOPIC EVIDENCE ON THE ORIGIN AND AGE OF THE BLIND RIVER URANIUM DEPOSITS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mair, J.A.; Maynes, A.D.; Patchett, J.E.

Isotopic analyses of lead extracted from a variety of minerals from Blind River. Ontario, are repeated. The detrital minerals monazite and zircon both give leadratio ages of 2500 million years. The uraainite ore gives a lead- ratio age of 1700 m a. Other isotopic evidence is quoted to suggest that the age of the sediment in which the uranium is found may also be approximately 1700 m y, or older. The lead found in pyrite, pyrrhotite, sericite, and feldspar has anomalous isotopic ratios which can be explained by the hypothesis that they received additions of radiogenic lead from the uraninitesmore » (presumed to be 1700 m y old) 1200 to 1300 m y ago. In any case the age of these minerals, in the sense of time of last chemical alteration, is not greater than 1450 plus or minus 150 m y. All our measurements can be interpreted without asauming a major period of mineralization more recent than 1000 m y ago, although we are unable to rule out such a possibility from our evidence. (auth)« less

Contributions to the geology of uranium and thorium by the United States Geological Survey and Atomic Energy Commission for the United Nations International Conference on Peaceful Uses of Atomic Energy, Geneva, Switzerland, 1955

USGS Publications Warehouse

Page, Lincoln R.; Stocking, Hobart E.; Smith, Harriet B.

1956-01-01

Within the boundaries of the United States abnormal amounts of uranium have been found in rocks of nearly all geologic ages and lithologic types. Distribution of ore is more restricted. On the Colorado Plateau, the Morrison formation of Jurassic age yields 61.4 percent of the ore produced in the United States, and the Chinle conglomerate and Shinarump formation of Triassic age contribute 26.0 and 5.8 percent, respectively. Clastic, carbonaceous, and carbonate sedimentary rocks of Tertiary, Mesozoic, and Paleozoic ages and veins of Tertiary age are the source of the remaining 6.8 percent.

Tellurium, a guide to mineral deposits

USGS Publications Warehouse

Watterson, J.R.; Gott, G.B.; Neuerburg, G.J.; Lakin, H.W.; Cathrall, J.B.

1977-01-01

Te dispersion patterns are useful in exploring for different types of mineral deposits and in providing additional information about known ore deposits. The Te content of rocks is given for five mining districts in the western United States: Coeur d'Alene, Idaho; Robinson, near Ely, Nevada; Montezuma, Colorado; Crater Creek area, Colorado; Cripple Creek, Colorado. Many of the analyses were obtained by use of a new analytical method sensitive to 0.001 ppm Te. The principal ore deposits in the Coeur d'Alene district, Idaho, are Pb-Zn-Ag replacement veins in Precambrian rocks of the Belt Supergroup. Te dispersion patterns show the outlines of the original mineral belts, the effects of intrusive events, the location of ore deposits, the displacements caused by post-ore faulting, and the borders of the 780-km2 district. The disseminated porphyry Cu deposits of the Robinson mining district, Nevada, are associated with Cretaceous quartz monzonite stocks that have intruded Palaeozoic carbonate rocks. Te is present in rock samples in concentrations as high as 10,000 ppm and forms a halo around the areas containing the Cu deposits. The alteration zones in the porphyry Mo district near Montezuma, Colorado, are developed around several small Tertiary intrusions occurring along a regional shear zone. Te haloes reflect the locations of porphyry intrusives, individual deposits and their ore shoots, and the pattern and intensity of adjacent alteration. The Te content of soils over the Montezuma stock is higher than, and varies independently from, the Te content of adjacent outcrops. Soils generally contain more Te than adjacent outcropping rocks. Soil may collect gaseous Te compounds from mineral deposits. The Crater Creek area is a northwestern extension of the Summitville mining district, Colorado. Te dispersion patterns radiate out from exposed Cu-Pb-Zn veins, from an outcrop of molybdenite stockwork veins and from associated iron-stained altered rock. Te haloes intensify exponentially with proximity to known ore and suggest the presence of Summitville-type chimney deposits. Most of the gold- and silver-telluride ore in the Cripple Creek district, Colorado, is found in fracture fillings within a volcanic subsidence basin. Haloes of Au, Ag and Te all define the mineralized portions of the fissure veins. ?? 1977.

Phanerozoic Rifting Phases And Mineral Deposits

NASA Astrophysics Data System (ADS)

Hassaan, Mahmoud

2016-04-01

In North Africa occur Mediterranean and Red Sea metallogenic provinces. In each province distribute 47 iron- manganese- barite and lead-zinc deposits with tectonic-structural control. The author presents in this paper aspects of position of these deposits in the two provinces with Phanerozoic rifting . The Mediterranean Province belongs to two epochs, Hercynian and Alpine. The Hercynian Epoch manganese deposits in only Moroccoa- Algeria belong to Paleozoic tectonic zones and Proterozoic volcanics. The Alpine Epoch iron-manganese deposits are of post-orogenic exhalative-sedimentary origin. Manganese deposits in southern Morocco occur in Kabil-Rief quartz-chalcedony veins controlled by faults in andesitic sheets and in bedded pelitic tuffs, strata-form lenses and ore veins, in Precambrian schist and in Triassic and Cretaceous dolomites. Disseminated manganese with quartz and barite and effusive hydrothermal veins are hosted in Paleocene volcanics. Manganese deposits in Algeria are limited and unrecorded in Tunisia. Strata-form iron deposits in Atlas Heights are widespread in sub-rift zone among Jurassic sediments inter-bedding volcanic rocks. In Algeria, Group Beni-Saf iron deposits are localized along the Mediterranean coast in terrigenous and carbonate rocks of Jurassic, Cretaceous and Eocene age within faults and bedding planes. In Morocco strata-form hydrothermal lead-zinc deposits occur in contact zone of Tertiary andesite inter-bedding Cambrian shale, Lias dolomites and Eocene andesite. In both Algeria and Tunisia metasomatic Pb-Zn veins occur in Campanian - Maastrichtian carbonates, Triassic breccia, Jurassic limestone, Paleocene sandstones and limestone and Neogene conglomerates and sandstones. The Red Sea metallogenic province belongs to the Late Tertiary-Miocene times. In Wadi Araba hydrothermal iron-manganese deposits occur in Cretaceous sediments within 320°and 310 NW faults related to Tertiary basalt. Um-Bogma iron-manganese deposits are closely connected with NW,WNW and N-S faults genetically related to volcano-hydrothermal activity associated the Red Sea rifting. At Sherm EL-Sheikh hydrothermal manganese deposit occurs in Oligocene clastics within fault zone. Four iron-manganese-barite mineralization in Esh-Elmellaha plateau are controlled by faults trending NW,NE and nearly E-W intersecting Miocene carbonate rocks. Barite exists disseminated in the ores and as a vein in NW fault. In Shalatee - Halaib district 24 manganese deposits and barite veins with sulphide patches occur within Miocene carbonates distributed along two NW fault planes,trending 240°and 310° and occur in granite and basalt . Uranium -lead-zinc sulfide mineralization occur in Late Proterozoic granite, Late Cretaceous sandstones, and chiefly in Miocene clastic-carbonate-evaporate rocks. The occurrences of uranium- lead-zinc and iron-manganese-barite mineralization have the characteristic features of hypogene cavity filling and replacement deposits correlated with Miocene- Recent Aden volcanic rocks rifting. In western Saudi Arabia barite-lead-zinc mineralization occurs at Lat. 25° 45' and 25° 50'N hosted by Tertiary sediments in limestone nearby basaltic flows and NE-SW fault system. The mineralized hot brines in the Red Sea deeps considered by the author a part of this province. The author considers the constant rifting phases of Pangea and then progressive fragmentation of Western Gondwana during the Late Carboniferous-Lias, Late Jurassic-Early Aptian, Late Aptian - Albian and Late Eocene-Early Miocene and Oligocene-Miocene, responsible for formation of the mineral deposits constituting the M provinces. During these events, rifting, magmatism and hydrothermal activities took place in different peri-continental margins.

Geological reconnaissance of some Uruguayan iron and manganese deposits in 1962

USGS Publications Warehouse

Wallace, Roberts Manning

1976-01-01

Three mineralized areas lie in an area near the town of Minas de Corrales in the Departamento de Rivera; they are the Cerro Amelia, the Cerro de Papagayo, and the Cerro Iman. The Cerro Amelia is composed of small bands of iron-rich rock separated by an amphibolitic or mafic rock. Selective mining would be necessary to extract the 31,000 tons per meter of depth of iron-rich rock that ranges from 15 to 40 percent metallic iron. The Cerro de Papagayo district contains many small, rich deposits of ferruginous manganese ore. The ratio of Mn to Fe varies widely within each small deposit as well as from deposit to deposit. Some ferruginous manganese ore contains 50-55 percent manganese dioxide. Although there are many thousands of tons of ore in the district, small-scale mining operations are imperative. One deposit, the Cerro Avestuz manganese mine, was visited. The manganese ore body lies within contorted highly metamorphosed itabirite that contains both hard low grade and soft high grade ferruginous manganese ores estimated to average 40 percent Mn. About 38,000 tons of manganese ore is present in this deposit. The Cerro Iman is a large block of itabirite that contains about 40 percent Fe. The grade is variable and probably runs from less than 35 percent Fe to more than 50 percent Fe. No exploration has been done on this deposit. It is recommended that the Cerro de Iman area be geologically mapped in detail, and that a geological reconnaissance be made of the area that is between the Cuchilla de Corrales and the Cuchilla de Areycua/Cuchilla del Cerro Pelado area.

Radioactive Contamination of Alluvial Soils in the Taiga Landscapes of Yakutia with 137Cs, 226Ra, and 238U

NASA Astrophysics Data System (ADS)

Chevychelov, A. P.; Sobakin, P. I.

2017-12-01

The concentrations and distribution of 137Cs in alluvial soils (Fluvisols) of the upper and middle reaches of the Markha River in the northwest of Yakutia and 226Ra and 238U in alluvial soils within the El'kon uranium ore deposit in the south of Yakutia have been studied. It is shown that the migration of radiocesium in the permafrost-affected soils of Yakutia owing to alluviation processes extends to more than 600 km from the source of the radioactive contamination. The migration of 137Cs with water flows is accompanied by its deposition in the buried horizons of alluvial soils during extremely high floods caused by ice jams. In the technogenic landscapes of southern Yakutia, active water migration of 238U and 226Ra from radioactive dump rocks. The leaching of 238U with surface waters from the rocks is more intense than the leaching of 226Ra. The vertical distribution patterns of 238U and 226Ra in the profiles of alluvial soils are complex. Uranium tends to accumulate in the surface humus horizon and in the buried soil horizons, whereas radium does not display any definite regularities of its distribution in the soil profiles. At present, the migration of 238U and 226Ra with river water and their accumulation in the alluvial soils extend to about 30 km from the source.

Microbial biogeochemistry of uranium mill tailings

USGS Publications Warehouse

Landa, Edward R.

2005-01-01

Uranium mill tailings (UMT) are the crushed ore residues from the extraction of uranium (U) from ores. Among the radioactive wastes associated with the nuclear fuel cycle, UMT are unique in terms of their volume and their limited isolation from the surficial environment. For this latter reason, their management and long-term fate has many interfaces with environmental microbial communities and processes. The interactions of microorganisms with UMT have been shown to be diverse and with significant consequences for radionuclide mobility and bioremediation. These radionuclides are associated with the U-decay series. The addition of organic carbon and phosphate is required to initiate the reduction of the U present in the groundwater down gradient of the mills. Investigations on sediment and water from the U-contaminated aquifer, indicates that the addition of a carbon source stimulates the rate of U removal by microbial reduction. Moreover, most attention with respect to passive or engineered removal of U from groundwaters focuses on iron-reducing and sulfate-reducing bacteria.

26 CFR 1.615-1 - Pre-1970 exploration expenditures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... facts and circumstances (including the actions of the taxpayer), deposits of ore or other mineral are... existence, location, extent, or quality of any deposit of ore or other mineral which will be incurred before... before January 1, 1970) for ascertaining the existence, location, extent, or quality of any deposit of...

Geology of the Gypsum Gap quadrangle, Colorado

USGS Publications Warehouse

Cater, Fred W.

1953-01-01

The Gypsum Gap quadrangle is one eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comparative study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through a arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The core consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

SLURRY SOLVENT EXTRACTION PROCESS FOR THE RECOVERY OF METALS FROM SOLID MATERIALS

DOEpatents

Grinstead, R.R.

1959-01-20

A solvent extraction process is described for recovering uranium from low grade uranium bearing minerals such as carnotit or shale. The finely communited ore is made up as an aqueous slurry containing the necessary amount of acid to solubilize the uranium and simultaneously or subsequently contacted with an organic solvent extractant such as the alkyl ortho-, or pyro phosphoric acids, alkyl phosphites or alkyl phosphonates in combination with a diluent such as kerosene or carbon tetrachlorids. The extractant phase is separated from the slurry and treated by any suitable process to recover the uranium therefrom. One method for recovering the uranium comprises treating the extract with aqueous HF containing a reducing agent such as ferrous sulfate, which reduces the uranium and causes it to be precipitated as uranium tetrafluoride.

The southwestern alaska mercury belt and its relationship to the circum-pacific metallogenic mercury province

USGS Publications Warehouse

Gray, J.E.; Gent, C.A.; Snee, L.W.

2000-01-01

A belt of small but numerous mercury deposits extends for about 500 km in the Kuskokwim River region of southwestern Alaska. The southwestern Alaska mercury belt is part of widespread mercury deposits of the circumPacific region that are similar to other mercury deposits throughout the world because they are epithermal with formation temperatures of about 200??C, the ore is dominantly cinnabar with Hg-Sb-As??Au geochemistry, and mineralized forms include vein, vein breccias, stockworks, replacements, and disseminations. The southwestern Alaska mercury belt has produced about 1,400 t of mercury, which is small on an international scale. However, additional mercury deposits are likely to be discovered because the terrain is topographically low with significant vegetation cover. Anomalous concentrations of gold in cinnabar ore suggest that gold deposits are possible in higher temperature environments below some of the Alaska mercury deposits. We correlate mineralization of the southwestern Alaska mercury deposits with Late Cretaceous and early Tertiary igneous activity. Our 40Ar/39Ar ages of 70??3 Ma from hydrothermal sericites in the mercury deposits indicate a temporal association of igneous activity and mineralization. Furthermore, we suggest that our geological and geochemical data from the mercury deposits indicate that ore fluids were generated primarily in surrounding sedimentary wall rocks when they were cut by Late Cretaceous and early Tertiary intrusions. In our ore genesis model, igneous activity provided the heat to initiate dehydration reactions and expel fluids from hydrous minerals and formational waters in the surrounding sedimentary wall rocks, causing thermal convection and hydrothermal fluid flow through permeable rocks and along fractures and faults. Our isotopic data from sulfide and alteration minerals of the mercury deposits indicate that ore fluids were derived from multiple sources, with most ore fluids originating from the sedimentary wall rocks.

Geology, ore facies and sulfur isotopes geochemistry of the Nudeh Besshi-type volcanogenic massive sulfide deposit, southwest Sabzevar basin, Iran

NASA Astrophysics Data System (ADS)

Maghfouri, Sajjad; Rastad, Ebrahim; Mousivand, Fardin; Lin, Ye; Zaw, Khin

2016-08-01

The southwest Sabzevar basin is placed in the southwestern part of a crustal domain known as the Sabzevar zone, at the north of Central Iranian microcontinent. This basin hosts abundant mineral deposits; particularly of the Mn exhalative and Cu-Zn volcanogenic massive sulfide (VMS) types. The evolution of this basin is governed by the Neo-tethys oceanic crust subduction beneath the Central Iranian microcontinent and by the resulting continental arc (Sanandaj-Sirjan) and back-arc (Sabzevar-Naien). This evolution followed two major sequences: (I) Lower Late Cretaceous Volcano-Sedimentary Sequence (LLCVSS), which is indicated by fine-grained siliciclastic sediments, gray basic coarse-grained different pyroclastic rocks and bimodal volcanism. During this stage, tuff-hosted stratiform, exhalative Mn deposits (Nudeh, Benesbourd, Ferizy and Goft), oxide Cu deposits (Garab and Ferizy) and Cu-Zn VMS (Nudeh, Chun and Lala) deposits formed. (II) Upper Late Cretaceous Sedimentary Dominated Sequence (ULCSS), including pelagic limestone, marly tuff, silty limestone and marl with minor andesitic tuff rocks. The economically most important Mn (Zakeri and Cheshmeh-sefid) deposits of Sabzevar zone occur within the marly tuff of this sequence. The Nudeh Cu-Zn volcanogenic massive sulfide (VMS) deposit is situated in the LLCVSS. The host-rock of deposits consists of alkali olivine basalt flow and tuffaceous silty sandstone. Mineralization occurs as stratiform blanket-like and tabular orebodies. Based on ore body structure, mineralogy, and ore fabric, we recognize three different ore facies in the Nudeh deposit: (1) a stringer zone, consisting of a discordant mineralization of sulfides forming a stockwork of sulfide-bearing quartz veins cutting the footwall volcano-sedimentary rocks; (2) a massive ore, consisting of massive replacement pyrite, chalcopyrite, sphalerite and Friedrichite with magnetite; (3) bedded ore, with laminated to disseminated pyrite, and chalcopyrite. Chloritization, silicification, sericitization and epidotization are the main wall-rock alterations; alteration intensity increases towards the stringer zone. The δ34S composition of the sulfides ranges from -1.5‰ to +3.69‰ with a general increase of δ34S ratios of massive ore facies to stockwork zone. The heavier values indicate that some of the sulfur was derived from seawater sulfate that was ultimately thermochemically reduced in deep hydrothermal reaction zones. Sulfur isotopes, along with sedimentological, textural, petrological, mineralogical, and geochemical evidences, suggest that this deposit should be classified as a Besshi-type VMS ore deposit.

Effect of acclimation to caging on nephrotoxic response of rats to uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damon, E.G.; Eidson, A.F.; Hobbs, C.H.

1986-02-01

Animal studies of the toxicity and metabolism of radionuclides and chemicals often require housing of rats in metabolism cages for excreta collection. Response of rats to toxic substances may be affected by environmental factors such as the type of cage used. Dose-response studies were conducted to assess the effects of two types of cages on the nephrotoxic response of rats to uranium from implanted refined uranium ore (yellowcake). The LD50/21 days was 6 mg of uranium ore per kilogram body weight (6 mg U/kg). The 95% confidence limit (C.L.) was 3-8 mg U/kg for rats housed in metabolism cages beginningmore » on the day of implantation (naive rats). However, for rats housed in metabolism cages for 21 days before implantation (acclimated rats) the LD50/21 days was 360 mg U/kg (95% C.L. = 220-650 mg U/kg), which was the same value obtained for rats housed continuously in polycarbonate cages. This significant difference (P less than 0.01) in response of naive rats compared to response of acclimated rats appeared related to a significantly lower water consumption by the naive rats.« less

Potential Treatment of Inflammatory and Proliferative Diseases by Ultra-Low Doses of Ionizing Radiations

PubMed Central

Sanders, Charles L.

2012-01-01

Ultra-low doses and dose- rates of ionizing radiation are effective in preventing disease which suggests that they also may be effective in treating disease. Limited experimental and anecdotal evidence indicates that low radiation doses from radon in mines and spas, thorium-bearing monazite sands and enhanced radioactive uranium ore obtained from a natural geological reactor may be useful in treating many inflammatory conditions and proliferative disorders, including cancer. Optimal therapeutic applications were identified via a literature survey as dose-rates ranging from 7 to 11μGy/hr or 28 to 44 times world average background rates. Rocks from an abandoned uranium mine in Utah were considered for therapeutic application and were examined by γ-ray and laser-induced breakdown fluorescence spectroscopy. The rocks showed the presence of transuranics and fission products with a γ-ray energy profile similar to aged spent uranium nuclear fuel (93% dose due to β particles and 7% due to γ rays). Mud packs of pulverized uranium ore rock dust in sealed plastic bags delivering bag surface β,γ dose-rates of 10–450 μGy/h were used with apparent success to treat several inflammatory and proliferative conditions in humans. PMID:23304108

Effect of acclimation to caging on nephrotoxic response of rats to uranium.

PubMed

Damon, E G; Eidson, A F; Hobbs, C H; Hahn, F F

1986-02-01

Animal studies of the toxicity and metabolism of radionuclides and chemicals often require housing of rats in metabolism cages for excreta collection. Response of rats to toxic substances may be affected by environmental factors such as the type of cage used. Dose-response studies were conducted to assess the effects of two types of cages on the nephrotoxic response of rats to uranium from implanted refined uranium ore (yellowcake). The LD50/21 days was 6 mg of uranium ore per kilogram body weight (6 mg U/kg). The 95% confidence limit (C.L.) was 3-8 mg U/kg for rats housed in metabolism cages beginning on the day of implantation (naive rats). However, for rats housed in metabolism cages for 21 days before implantation (acclimated rats) the LD50/21 days was 360 mg U/kg (95% C.L. = 220-650 mg U/kg), which was the same value obtained for rats housed continuously in polycarbonate cages. This significant difference (P less than 0.01) in response of naive rats compared to response of acclimated rats appeared related to a significantly lower water consumption by the naive rats.

Age and origin of base and precious metal veins of the Coeur d'Alene mining district, Idaho

USGS Publications Warehouse

Fleck, R.J.; Criss, R.E.; Eaton, G.F.; Cleland, R.W.; Wavra, C.S.; Bond, W.D.

2002-01-01

Ore-bearing quartz-carbonate veins of the Coeur d'Alene mining district yield 87Sr/86Sr ratios of 0.74 to >1.60 for low Rb/Sr, carbonate gangue minerals, similar to current ranges measured in Middle Proterozoic, high Rb/Sr rocks of the Belt Supergroup. Stable isotope and fluid inclusion studies establish a genetic relationship between vein formation and metamorphic-hydrothermal systems of the region. These extraordinary 87Sr/86Sr ratios require accumulation of radiogenic 87Sr in a high Rb/Sr system over an extended period prior to incorporation of Sr into the hydrothermal veins. Evaluation of the age and composition of potential sources of highly radiogenic Sr indicates that the ore-bearing veins of the Coeur d'Alene district formed during the Cretaceous from components scavenged from rocks of the Belt Supergroup, the primary host rocks of the district. Proterozoic Pb isotope ratios observed in galena from many Coeur d'Alene veins were established when Pb separated from uranium during deposition or diagenesis of the Belt Supergroup at 1400 to 1500 Ma, possibly as disseminated syngenetic deposits. K-Ar and Rb-Sr apparent ages and ??18O values of Belt Supergroup rocks decrease from the Coeur d'Alene district toward the Idaho and Kaniksu batholiths, approximately normal to the trends of metamorphic isograds, fold axes, foliation, and the major reverse faults of the district. Isoclinal folding, thrust faulting, high-temperature metamorphism, granitic plutonism, and regional-scale metamorphic-hydrothermal activity is documented in the region between 140 and 45 Ma, representing the only such combination of events in the Coeur d'Alene region subsequent to about 1300 Ma. The Sr and oxygen results and geologic evidence favor formation of the ore-bearing carbonate veins by fluids related to a complex metamorphic-hydrothermal system during the Cretaceous. Pb with Proterozoic isotopic compositions was probably mobilized and incorporated like other metals into the hydrothermal veins during this event. The ore-bearing veins were sheared and displaced during early Tertiary northwest-trending dextral strike-slip faulting along the Osburn fault and related structures of the Lewis and Clark line.

Quantifying uranium transport rates and storage of fluvially eroded mine tailings from a historic mine site in the Grand Canyon Region

NASA Astrophysics Data System (ADS)

Skalak, K.; Benthem, A. J.; Walton-Day, K. E.; Jolly, G.

2015-12-01

The Grand Canyon region contains a large number of breccia pipes with economically viable uranium, copper, and silver concentrations. Mining in this region has occurred since the late 19th century and has produced ore and waste rock having elevated levels of uranium and other contaminants. Fluvial transport of these contaminants from mine sites is a possibility, as this arid region is susceptible to violent storms and flash flooding which might erode and mobilize ore or waste rock. In order to assess and manage the risks associated with uranium mining, it is important to understand the transport and storage rates of sediment and uranium within the ephemeral streams of this region. We are developing a 1-dimensional sediment transportation model to examine uranium transport and storage through a typical canyon system in this region. Our study site is Hack Canyon Mine, a uranium and copper mine site, which operated in the 1980's and is currently experiencing fluvial erosion of its waste rock repository. The mine is located approximately 40km upstream from the Colorado River and is in a deep, narrow canyon with a small watershed. The stream is ephemeral for the upper half of its length and sediment is primarily mobilized during flash flood events. We collected sediment samples at 110 locations longitudinally through the river system to examine the distribution of uranium in the stream. Samples were sieved to the sand size and below fraction (<2mm) and uranium was measured by gamma-ray spectroscopy. Sediment storage zones were also examined in the upper 8km of the system to determine where uranium is preferentially stored in canyon systems. This information will quantify the downstream transport of constituents associated with the Hack Canyon waste rock and contribute to understanding the risks associated with fluvial mobilization of uranium mine waste.

A synthesis of mineralization styles and geodynamic settings of the Paleozoic and Mesozoic metallic ore deposits in the Altay Mountains, NW China

NASA Astrophysics Data System (ADS)

Yang, Fuquan; Geng, Xinxia; Wang, Rui; Zhang, Zhixin; Guo, Xuji

2018-06-01

The Altay Mountains within the Xinjiang region of northwestern China hosts major metallic ore deposits. Here we review the geological characteristics, metallogenic features and tectonic settings of these deposits. The metallic ore deposits in the Altay Mountains occur mainly within four regions: North Altay, Central Altay, South Altay and Erqis. We recognize seven types of metallic ore deposits in the Altay Mountains: VMS, submarine volcanogenic iron, magmatic, skarn, pegmatite, hydrothermal vein (Cu-Zn, Fe) and orogenic gold. Among these types, the VMS, pegmatite, orogenic gold and skarn deposits are the most common. Most of the rare metal pegmatite deposits are distributed in Central Altay, with only a few in South Altay. The VMS, submarine volcanogenic type iron and skarn-type deposits are distributed in South Altay, whereas the orogenic-type gold deposits are distributed in the Erqis Fault belt. The hydrothermal vein-type deposits occur in the Erqis Fault belt and Chonghu'er Basin in South Altay. Magmatic-type deposits are mostly in the Erqis Fault belt and Central Altay. Based on isotopic age data, the VMS, submarine volcanogenic-type Fe and skarn-type Cu, Pb, Zn, Fe mineralization occurred during Early-Middle Devonian (∼410-377 Ma), orogenic-type Au, magmatic-type Cu-Ni, and a small number of skarn-type Fe, hydrothermal vein-type Cu-Zn, pegmatite-type rare-metal deposits in Early-Middle Permian (293-261 Ma), pegmatite-type rare-metal deposits, few skarn-type Fe deposit in Early-Middle Triassic (248-232 Ma), and dominantly represented by pegmatite-type rare-metal deposits in Late Triassic-Early Jurassic (223-180 Ma). The metallic ore deposits in the Altay Mountains formed in various tectonic settings, such as the Early-Middle Devonian continental arc and oceanic island arc, Early-Middle Permian post-collisional extensional setting, and Triassic-Early Jurassic intracontinental setting.

Geological and geochemical aspects of uranium deposits. A selected, annotated bibliography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garland, P.A.; Thomas, J.M.; Brock, M.L.

1980-06-01

A bibliography of 479 references encompassing the fields of uranium and thorium geochemistry and mineralogy, geology of uranium deposits, uranium mining, and uranium exploration techniques has been compiled by the Ecological Sciences Information Center of Oak Ridge National Laboratory. The bibliography was produced for the National Uranium Resource Evaluation Program, which is funded by the Grand Junction Office of the Department of Energy. The references contained in the bibliography have been divided into the following eight subject categories: (1) geology of deposits, (2) geochemistry, (3) genesis O deposits, (4) exploration, (5) mineralogy, (6) uranium industry, (7) reserves and resources, andmore » (8) geology of potential uranium-bearing areas. All categories specifically refer to uranium and thorium; the last category contains basic geologic information concerning areas which the Grand Junction Office feels are particularly favorable for uranium deposition. The references are indexed by author, geographic location, quadrangle name, geoformational feature, taxonomic name, and keyword.« less

Maps showing the distribution of uranium-deposit clusters in the Colorado Plateau uranium province

USGS Publications Warehouse

Finch, Warren I.

1991-01-01

The Colorado Palteau Uranium Province (CPUP) is defined by the distribution of uranium deposits, chiefly the sandstone-type, in upper Paleozoic and Mesozoic sedimentary rocks within the Colorado Plateau physiographic province (Granger and others, 1986).  The uranium province is bordered by widely distributed and mostly minor uranium deposits in Precambrian and Tertiary rocks and by outcrops of Tertiary extrusive and intrusive igneous rocks.  

Characterization of Uranium Ore Concentrate Chemical Composition via Raman Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Yin-Fong; Tonkyn, Russell G.; Sweet, Lucas E.

Uranium Ore Concentrate (UOC, often called yellowcake) is a generic term that describes the initial product resulting from the mining and subsequent milling of uranium ores en route to production of the U-compounds used in the fuel cycle. Depending on the mine, the ore, the chemical process, and the treatment parameters, UOC composition can vary greatly. With the recent advent of handheld spectrometers, we have chosen to investigate whether either commercial off-the-shelf (COTS) handheld devices or laboratory-grade Raman instruments might be able to i) identify UOC materials, and ii) differentiate UOC samples based on chemical composition and thus suggest themore » mining or milling process. Twenty-eight UOC samples were analyzed via FT-Raman spectroscopy using both 1064 nm and 785 nm excitation wavelengths. These data were also compared with results from a newly developed handheld COTS Raman spectrometer using a technique that lowers background fluorescence signal. Initial chemometric analysis was able to differentiate UOC samples based on mine location. Additional compositional information was obtained from the samples by performing XRD analysis on a subset of samples. The compositional information was integrated with chemometric analysis of the spectroscopic dataset allowing confirmation that class identification is possible based on compositional differences between the UOC samples, typically involving species such as U3O8, α-UO2(OH)2, UO4•2H2O (metastudtite), K(UO2)2O3, etc. While there are clearly excitation λ sensitivities, especially for dark samples, Raman analysis coupled with chemometric data treatment can nicely differentiate UOC samples based on composition and even mine origin.« less

Dense Medium Ore Concentrates of Bois-Noirs; MINERAIS DES BOIS NOIRS CONCENTRES DE MILIEU DENSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Bris, J.; Leduc, M.

1959-01-01

The chemical treatment of uranium concentrates of BoisNoirs ore obtained by heavy medium are discussed. The first part deals with sulfuric acid attack on the concentrate, and the second part with the separation of the solution from residues by filtration. A third part deals with this separation by decantation. The fourth part deals with the carbonation of the pickling solutions obtained. (auth)

The origin of Cu/Au ratios in porphyry-type ore deposits.

PubMed

Halter, Werner E; Pettke, Thomas; Heinrich, Christoph A

2002-06-07

Microanalysis of major and trace elements in sulfide and silicate melt inclusions by laser-ablation inductively coupled plasma mass spectrometry indicates a direct link between a magmatic sulfide liquid and the composition of porphyry-type ore deposits. Copper (Cu), gold (Au), and iron (Fe) are first concentrated in a sulfide melt during magmatic evolution and then released to an ore-forming hydrothermal fluid exsolved late in the history of a magma chamber. The composition of sulfide liquids depends on the initial composition and source of the magma, but it also changes during the evolution of the magma in the crust. Magmatic sulfide melts may exert the dominant direct control on the economic metal ratios of porphyry-type ore deposits.

Ore deposits in Africa and their relation to the underlying mantle

NASA Technical Reports Server (NTRS)

Liu, H.-S.

1981-01-01

African magmatism is largely related to the tensional stress regimes of the crust which are induced by the hotter upwelling mantle rocks. These mantle rocks may provide emanating forces and thermal energy for the upward movements of primary ore bodies with fluid inclusions in the tensional stress regimes of the crust. In this paper, the Goddard Earth Gravity Model is used to calculate a detailed subcrustal stress system exerted by mantle convection under Africa. The resulting system is found to be correlated with the African metallogenic provinces. Recognition of the full spectrum of ore deposits in Africa that may be associated with the hotter upwelling mantle rocks has provided an independent evidence to support the hypothesis of mantle-derived heat source for ore deposits.

Bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance

NASA Astrophysics Data System (ADS)

Laskou, Magdalini; Economou-Eliopoulos, Maria

2013-08-01

The Parnassos-Ghiona bauxite deposit in Greece of karst type is the 11th largest bauxite producer in the world. The mineralogical, major and trace-element contents and δ18O, δ12C, δ34S isotopic compositions of bauxite ores from this deposit and associated limestone provide valuable evidence for their origin and biogeochemical processes resulting in the beneficiation of low grade bauxite ores. The organic matter as thin coal layers, overlying the bauxite deposits, within limestone itself (negative δ12C isotopic values) and the negative δ34S values in sulfides within bauxite ores point to the existence of the appropriate circumstances for Fe bio-leaching and bio-mineralization. Furthermore, a consortium of microorganisms of varying morphological forms (filament-like and spherical to lenticular at an average size of 2 μm), either as fossils or presently living and producing enzymes, is a powerful factor to catalyze the redox reactions, expedite the rates of metal extraction and provide alternative pathways for metal leaching processes resulting in the beneficiation of bauxite ore.

Exposure pathways and biological receptors: baseline data for the canyon uranium mine, Coconino County, Arizona

USGS Publications Warehouse

Hinck, Jo E.; Linder, Greg L.; Darrah, Abigail J.; Drost, Charles A.; Duniway, Michael C.; Johnson, Matthew J.; Méndez-Harclerode, Francisca M.; Nowak, Erika M.; Valdez, Ernest W.; van Riper, Charles; Wolff, S.W.

2014-01-01

Recent restrictions on uranium mining within the Grand Canyon watershed have drawn attention to scientific data gaps in evaluating the possible effects of ore extraction to human populations as well as wildlife communities in the area. Tissue contaminant concentrations, one of the most basic data requirements to determine exposure, are not available for biota from any historical or active uranium mines in the region. The Canyon Uranium Mine is under development, providing a unique opportunity to characterize concentrations of uranium and other trace elements, as well as radiation levels in biota, found in the vicinity of the mine before ore extraction begins. Our study objectives were to identify contaminants of potential concern and critical contaminant exposure pathways for ecological receptors; conduct biological surveys to understand the local food web and refine the list of target species (ecological receptors) for contaminant analysis; and collect target species for contaminant analysis prior to the initiation of active mining. Contaminants of potential concern were identified as arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, thallium, uranium, and zinc for chemical toxicity and uranium and associated radionuclides for radiation. The conceptual exposure model identified ingestion, inhalation, absorption, and dietary transfer (bioaccumulation or bioconcentration) as critical contaminant exposure pathways. The biological survey of plants, invertebrates, amphibians, reptiles, birds, and small mammals is the first to document and provide ecological information on .200 species in and around the mine site; this study also provides critical baseline information about the local food web. Most of the species documented at the mine are common to ponderosa pine Pinus ponderosa and pinyon–juniper Pinus–Juniperus spp. forests in northern Arizona and are not considered to have special conservation status by state or federal agencies; exceptions are the locally endemic Tusayan flameflower Phemeranthus validulus, the long-legged bat Myotis volans, and the Arizona bat Myotis occultus. The most common vertebrate species identified at the mine site included the Mexican spadefoot toad Spea multiplicata, plateau fence lizard Sceloporus tristichus, violetgreen swallow Tachycineta thalassina, pygmy nuthatch Sitta pygmaea, purple martin Progne subis, western bluebird Sialia mexicana, deermouse Peromyscus maniculatus, valley pocket gopher Thomomys bottae, cliff chipmunk Tamias dorsalis, black-tailed jackrabbit Lepus californicus, mule deer Odocoileus hemionus, and elk Cervus canadensis. A limited number of the most common species were collected for contaminant analysis to establish baseline contaminant and radiological concentrations prior to ore extraction. These empirical baseline data will help validate contaminant exposure pathways and potential threats from contaminant exposures to ecological receptors. Resource managers will also be able to use these data to determine the extent to which local species are exposed to chemical and radiation contamination once the mine is operational and producing ore. More broadly, these data could inform resource management decisions on mitigating chemical and radiation exposure of biota at high-grade uranium breccia pipes throughout the Grand Canyon watershed.

Caves, mines and subterranean spaces: hazard and risk from exposure to radon.

NASA Astrophysics Data System (ADS)

Crockett, R. G. M.; Gillmore, G. K.

2009-04-01

Radon is a naturally occurring radioactive gas. It is colourless, odourless and chemically inert. The most hazardous isotope is 222Rn. Radon is formed in the natural environment by the radioactive decay of the element uranium (238U) and is a daughter product of daughter product of radium (226Ra). Uranium and radium are found, in differing degrees, in a wide range of rocks, soils (and building materials that are made from these). Radon concentrations in caves, e.g. limestone caves such as the Great Cave of Niah, Borneo, and caves in the Mendips and Peak District in the UK, has been documented and reveal that both (prehistoric) cave-dwellers and other users such as archaeologists are at risk from exposure to radon a naturally occurring radioactive gas. In general, but dependent on cave geometry and ventilation, radon concentration increases with increasing distance from the entrance, implying that the hazard also increases with distance from the entrance. With regard to mines and mining operations, as well as modern extraction of uranium and radium ores, both ores commonly occur alongside other metallic ores, e.g. silver at Schneeberg and Joachimsthal, and tin in Cornwall, and in some instances, waste from earlier metalliferious mining activity has itself been ‘mined' for uranium and/or radium ores. It is not solely the miners and other subterranean workers which are at risk, other workers and local inhabitants are also at risk. Also, that risk is not eliminated by protection against dust/airborne particulates: the risk from inhalation of radon is only reduced by reducing the inhalation of radon, i.e. use of breathing apparatus. Amongst the general population, radon is the second most significant cause of lung cancer behind tobacco smoking. Estimates vary but 6-9% of lung-cancers are attributable to radon and approximately 2% all cancer deaths are attributable to radon. These proportions will increase in higher-radon environments such as caves, mines and mining areas (via spoil heaps, settlement lagoons etc. containing uranium and radium). We here present an overview of the potential hazard presented by radon in subterranean spaces and by metalliferous mining activities. We also present some speculation as to evidence of (pre-) historic exposure to radon which might potentially exist in archaeological remains and oral traditions. Keywords: radon; caves; metalliferous mining; cave-dwellers; archaeologists.

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNamara, Bruce K.; O’Hara, Matthew J.; Casella, Andrew M.

2016-07-01

Abstract: We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other uranium compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within the chamber to a highly predictable degree. We demonstrate the preparation of uranium deposits that range between ~0.01 and 470±34 ng∙cm-2. The data suggest the method can be extended to creating depositions at the sub-picogram∙cm-2 level. Additionally, the isotopic composition of the deposits can be customized by selection of the uranium source materials. Wemore » demonstrate a layering technique whereby two uranium solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit of UF6 that bears an isotopic signature that is a composite of the two uranium sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics.« less

Geology and ore fluid geochemistry of the Jinduicheng porphyry molybdenum deposit, East Qinling, China

NASA Astrophysics Data System (ADS)

Li, Hongying; Ye, Huishou; Wang, Xiaoxia; Yang, Lei; Wang, Xiuyuan

2014-01-01

Jinduicheng deposit is a giant Mesozoic porphyry Mo system deposit in the East Qinling molybdenum belt, Shaanxi Province, China. The mineralization is associated with the I-type Jinduicheng granite porphyry. Both the porphyry stock and country rocks underwent intense hydrothermal alteration. The alteration, with increasing distance from the parent intrusion, changes from silicification, through potassic and phyllic assemblages, carbonation, to propylitic assemblages. Molybdenite, the dominant ore mineral, occurs in veinlets, most of which are hosted by the altered country rocks, with less than 25% of the ore in the porphyry body. The hydrothermal system comprises four stages, including pre-ore quartz and K-feldspar; two ore stages of quartz, K-feldspar, molybdenite, and Pb- And Zn-bearing sulfides; and post-ore quartz and carbonate. Six main types of primary fluid inclusions are present in hydrothermal quartz, including two-phase aqueous, one-phase aqueous, three-phase CO2-bearing, CO2-dominated fluid inclusions, gas inclusions, and melt inclusions. The homogenization temperatures of fluid inclusions range from 210 to 290 °C in the pre-ore stage, 150-310 °C in ore stage I, 150-360 °C in the ore stage II, and 195-325 °C in the post-ore stage quartz. Estimated salinities of the ore-forming fluids range from 6.9 to 13.5, 4.3 to 12.3, 6.2 to 12.4, and 3.4 to 9.9 wt.% NaCl equiv. in stages 1-4, respectively. The δ34S values of pyrite in the two ore stages range from 2.8‰ to 4.3‰, whereas the δ34S values of molybdenite range from 2.9‰ to 6.2‰. The data suggest both magmatic and crustal sources of sulfur. The δD and δ18O values for the hydrothermal fluids are -57.2‰ to -84.4‰ and 8.0‰ to -3.2‰, respectively. The fluid inclusion and stable data indicate that the pre-ore hydrothermal fluids were mostly of magmatic origin, but the fluids responsible for ore deposition were mixed magmatic and meteoric, and eventually meteoric water dominated the system in the post-ore stage.

Life-Cycle environmental impact assessment of mineral industries

NASA Astrophysics Data System (ADS)

Hisan Farjana, Shahjadi; Huda, Nazmul; Parvez Mahmud, M. A.

2018-05-01

Mining is the extraction and processing of valuable ferro and non-ferro metals and minerals to be further used in manufacturing industries. Valuable metals and minerals are extracted from the geological deposits and ores deep in the surface through complex manufacturing technologies. The extraction and processing of mining industries involve particle emission to air or water, toxicity to the environment, contamination of water resources, ozone layer depletion and most importantly decay of human health. Despite all these negative impacts towards sustainability, mining industries are working throughout the world to facilitate the employment sector, economy and technological growth. The five most important miners in the world are South Africa, Russia, Australia, Ukraine, Guinea. The mining industries contributes to their GDP significantly. However, the most important issue is making the mining world sustainable thus reducing the emissions. To address the environmental impacts caused by the mining sectors, this paper is going to analyse the environmental impacts caused by the 5 major minerals extraction processes, which are bauxite, ilmenite, iron ore, rutile and uranium by using the life-cycle impact assessment technologies. The analysis is done here using SimaPro software version 8.4 using ReCipe, CML and Australian indicator method.

Using marine magnetic survey data to identify a gold ore-controlling fault: a case study in Sanshandao fault, eastern China

NASA Astrophysics Data System (ADS)

Yan, Jiayong; Wang, Zhihui; Wang, Jinhui; Song, Jianhua

2018-06-01

The Jiaodong Peninsula has the greatest concentration of gold ore in China and is characterized by altered tectonite-type gold ore deposits. This type of gold deposit is mainly formed in fracture zones and is strictly controlled by faults. Three major ore-controlling faults occur in the Jiaodong Peninsula—the Jiaojia, Zhaoping and Sanshandao faults; the former two are located on land and the latter is located near Sanshandao and its adjacent offshore area. The discovery of the world’s largest marine gold deposit in northeastern Sanshandao indicates that the shallow offshore area has great potential for gold prospecting. However, as two ends of the Sanshandao fault extend to the Bohai Sea, conventional geological survey methods cannot determine the distribution of the fault and this is constraining the discovery of new gold deposits. To explore the southwestward extension of the Sanshandao fault, we performed a 1:25 000 scale marine magnetic survey in this region and obtained high-quality magnetic survey data covering 170 km2. Multi-scale edge detection and three-dimensional inversion of magnetic anomalies identify the characteristics of the southwestward extension of the Sanshandao fault and the three-dimensional distribution of the main lithologies, providing significant evidence for the deployment of marine gold deposit prospecting in the southern segment of the Sanshandao fault. Moreover, three other faults were identified in the study area and faults F2 and F4 are inferred as ore-controlling faults: there may exist other altered tectonite-type gold ore deposits along these two faults.

Difference in rockburst hazard in ore and coal mines

NASA Astrophysics Data System (ADS)

Lovchikov, AV

2018-03-01

In the Russian mining and engineering literature, in most cases, there is no difference in the assessment of the rockburst hazards in metal and coal mines. Nevertheless, it exists, in view of the difference in geological and geotechnical conditions of coal and ore deposits. Since ore deposits occur in the solid magmatic or metamorphic rock masses, the strongest induced earthquakes are much more powerful in ore mines than in coal mines. The main difference of rockbursting lies in the difference of natural stress state: gravity stress state in the coal fields and gravity-and-tectonic stress state in ore mines. The actual stresses are mostly vertical in the first case and horizontal in the second case, which conditions the difference in rockburst hazard in coal and ore mines.

Use of structural geology in exploration for and mining of sedimentary rock-hosted Au deposits

USGS Publications Warehouse

Peters, Stephen G.

2001-01-01

Structural geology is an important component in regional-, district- and orebody-scale exploration and development of sedimentary rock-hosted Au deposits.Identification of timing of important structural events in an ore district allows analysis and classification of fluid conduits and construction of genetic models for ore formation.The most practical uses of structural geology deal with measurement and definition of various elements that comprise orebodies, which can then be directly applied to ore-reserve estimation,ground control,grade control, safety issues,and mine planning.District- and regional-scale structural studies are directly applicable to long-term strategic planning,economic analysis,and land ownership. Orebodies in sedimentary rock-hosted Au deposits are discrete, hypogene, epigenetic masses usually hosted in a fault zone,breccia mass, or lithologic bed or unit. These attributes allow structural geology to be directly applied to the mining and exploration of sedimentary rock-hosted Au deposits. Internal constituents in orebodies reflect unique episodes relating to ore formation.The main internal constituents in orebodies are ore minerals, gangue, and alteration minerals that usually are mixed with one another in complex patterns, the relations among which may be used to interpret the processes of orebody formation and control.Controls of orebody location and shape usually are due to structural dilatant zones caused by changes in attitude, splays, lithologic contacts,and intersections of the host conduit or unit.In addition,conceptual parameters such as district fabric,predictable distances, and stacking also are used to understand the geometry of orebodies.Controls in ore districts and location and geometry of orebodies in ore districts can be predicted to various degrees by using a number of qualitative concepts such as internal and external orebody plunges,district plunge, district stacking, conduit classification, geochemical, geobarometric and geothermal gradients, and tectonic warps. These concepts have practical and empirical application in most mining districts where they are of use in the exploration for ore, but are of such broad and general application that they may not represent known or inferred ore formation processes. Close spatial relation among some sedimentary rock- hosted Au deposits and their host structures suggests that the structures and the orebodies are genetically linked because they may have shared the same developmental history. Examples of probable syn-deformational genesis and structural control of sedimentary rock-hosted Au deposits are in the large Betze deposit in the Carlin trend, Nevada and in the Lannigou, Jinlongshan, and Maanqiao Au deposits, China.

Long-Term Planning for Open Pits for Mining Sulphide-Oxide Ores in Order to Achieve Maximum Profit

NASA Astrophysics Data System (ADS)

Kržanović, Daniel; Conić, Vesna; Stevanović, Dejan; Kolonja, Božo; Vaduvesković, Jovan

2017-12-01

Profitable exploitation of mineralised material from the earth's crust is a complex and difficult task that depends on a comprehensive planning process. Answering the question of how to plan production depends on the geometry of the deposit, as well as the concentration, distribution, and type of minerals in it. The complex nature of mineral deposits largely determines the method of exploitation and profitability of mining operations. In addition to unit operating costs and metal prices, the optimal recovery of and achievement of maximum profit from deposits of sulphide-oxide ores also depend, to a significant extent, on the level of technological recovery achieved in the ore processing procedure. Therefore, in defining a long-term development strategy for open pits, special attention must be paid to the selection of an optimal procedure for ore processing in order to achieve the main objective: maximising the Net Present Value (NPV). The effect of using two different processes, flotation processing and hydrometallurgical methods (bioleaching acid leaching), on determining the ultimate pit is shown in the case of the Kraku Bugaresku-Cementacija sulphide-oxide ore deposit in eastern Serbia. Analysis shows that the application of hydrometallurgical methods of processing sulphide-oxide ore achieved an increase in NPV of 20.42%.

Sedimentary exhalative nickel-molybdenum ores in south China

USGS Publications Warehouse

Lott, D.A.; Coveney, R.M.; Murowchick, J.B.; Grauch, R.I.

1999-01-01

Unique bedded Ni-Mo ores hosted by black shales were discovered in localized paleobasins along the Yangzte platform of southern China in 1971. Textural evidence and radiometric dates imply ore formation during sedimentation of black shales that grade into readily combustible beds, termed stone coals, which contain 10 to 15 percent organic carbon. Studies of 427 fluid inclusions indicate extreme variation in hydrothermal brine salinities that were contained by Proterozoic dolostones underlying the ore zone in Hunan and Guizhou. Variations of fluid inclusion salinities, which range from 0.1 to 21.6 wt percent NaCl equiv, are attributed to differences in the compositions of brines in strata underlying the ore bed, complicated by the presence of seawater and dilute fluids that represent condensates of vapors generated by boiling of mineralizing fluids or Cambrian meteoric water. The complex processes of ore deposition led to scattered homogenization temperatures ranging from 100??to 187??C within the Hunan ore zone and from 65??to 183??C within the Guizhou ore zone. While living organisms probably did not directly accumulate metals in situ in sufficient amounts to explain the unusually high grades of the deposits, sulfur isotope ratios indicate that bacteria, now preserved as abundant microfossils, provided sufficient sulfide for the ores by reduction of seawater sulfate. Such microbiota may have depended on vent fluids and transported organic matter for key nutrients and are consistent with a sedex origin for the ores. Vent fluids interacted with organic remains, including rounded fragments of microbial mats that were likely transported to the site of ore deposition by the action of waves and bottom currents prior to replacement by ore minerals.

Uranium Mining and Norm in North America-Some Perspectives on Occupational Radiation Exposure.

PubMed

Brown, Steven H; Chambers, Douglas B

2017-07-01

All soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.S., these materials are sometimes referred to as technologically-enhanced naturally occurring radioactive materials (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertilizer. The processing of these materials has the potential to result in above-background radiation exposure to workers. Following a brief review of the sources and potential for worker exposure from NORM in these varied industries, this paper will then present an overview of uranium mining and recovery in North America, including discussion on the mining methods currently being used for both conventional (underground, open pit) and in situ leach (ISL), also referred to as In Situ Recovery (ISR), and the production of NORM materials and wastes associated with these uranium recovery methods. The radiological composition of the NORM products and wastes produced and recent data on radiological exposures received by workers in the North American uranium recovery industry are then described. The paper also identifies the responsible government agencies in the U.S. and Canada assigned the authority to regulate and control occupational exposure from these NORM materials.

Antimony ore in the Fairbanks district, Alaska

USGS Publications Warehouse

Killeen, Pemberton Lewis; Mertie, John B.

1951-01-01

Antimony-bearing ores in the Fairbanks district, Alaska, are found principally in two areas, the extremities of which are at points 10 miles west and 23 miles northeast of Fairbanks; and one of two minor areas lies along this same trend 30 miles farther to the northeast. These areas are probably only local manifestations of mineralization that affected a much broader area and formed antimony-bearing deposits in neighboring districts, the closest of which is 50 miles away. The ores were exposed largely as a result of lode gold mining, but at two periods in the past, high prices for antimony ore warranted an independent production and about 2500 tons of stibnite ore was shipped. The sulfide deposits occupy the same fractures along which a gold-quartz mineralization of greater economic importance occurred; and both are probably genetically related to igneous rocks which intrude the schistose country rock. The sulfide is in part contemporaneous with some late-stage quartz in which it occurs as disseminated crystals; and in part the latest filling in the mineralized zones where it forms kidney-shaped masses of essentially solid sulfide. One extremely long mass must have contained nearly 100 tons of ore, but the average of the larger kidneys is closer to several tons. Much of the ore is stibnite, with quartz as a minor impurity, and assays show the tenor to vary from 40 to 65 percent antimony. Sulphantimonites are less abundant but likewise occur as disseminated crystals and as kidney-shaped bodies. Antimony oxides appear on the weathered surface and along fractures within the sulfide ore. Deposits containing either stibnite or sulphantimonite are known at more than 50 localities, but only eighteen have produced ore and the bulk of this came from the mines. The geology of the deposit, and the nature, extent, and period of the workings are covered in the detailed descriptions of individual occurrences. Several geologic and economic factors, which greatly affect prospecting and mining for stibnite ore in the area, are outlined. The principal available ore and reserves are considered to be ores earlier mined but never shipped, ore minable from near-surface deposits, and ores recoverable as a by-product of future gold mining. The outlook for stibnite production in the district is very uncertain. Apparently the greater portion of stibnite ore has already been recovered and present operations will strip the two principal areas of the district. This conclusion is based on the scanty discoveries since the last war and the fact that the areas are so pock-marked with prospects that there is little likelihood that any other large near-surface bodies remain to be discovered. Future prospecting would essentially be limited to attempts to seek the continuation of lodes previously having high yields of stibnite.

Uranium deposits of the northern part of the Boulder Batholith, Montana

USGS Publications Warehouse

Becraft, George E.

1955-01-01

Uranium minerals and radioactivity anomalies occur in many silver-lead veins and chalcedony veins and vein zones in the Boulder batholith of southwestern Montanao Pitchblende has been identified in a few silver-lead veins. These veins occupy shear zones along which there is no evidence of large-scale lateral displacement. The wall rock adjacent to the veins is intensely silicified and sencitized quartz monzonite and granodiortte. The veins have yielded substantial quantities of lead, silver, zinc, and gold. The silver-lead veins consist principal1y of galena, spha1erite, tetrahedrite, cha1copyrite and pyrite in a gangue of light to dark gray quartz, altered rock, gouge, and subordinate chalcedony and carbonate minerals. No anomalous radioactivity nor uranium minerals have been found in similar veins in pre-batholithic rocks of the area. Chalcedony veins and vein zones, some of which are ttraniferous, are distinctly different from the silver-lead veins and, with a single except1on, are known only in the batholith. The chalcedony vein zones consist of one or more discontinuous stringers or veins of cha1cedony and microcrystalline quartz in silicified and sericitized quartz monzonite and granodiorite, and in less strongly altered alaskite. On1y small amounts of silver ore have been produced from these chalcedony veins and vein zones. All of the veins are ear1y Tertiary in age, but the silver-lead veins probably are older than the chalcedony veins. Uranium is closely associated with chalcedory and microcrystalline quartz in both types of veins. This association suggests that all of the uranium in the area is of the same age. If so, some of the silver-lead veins must have been reopened during the period of chalcedony vein formation.

Hydrological, geological, and biological site characterization of breccia pipe uranium deposits in Northern Arizona

USGS Publications Warehouse

Alpine, Andrea E.

2010-01-01

On July 21, 2009, U.S. Secretary of the Interior Ken Salazar proposed a two-year withdrawal of about 1 million acres of Federal land near the Grand Canyon from future mineral entry. These lands are contained in three parcels: two parcels on U.S. Bureau of Land Management land to the north of the Grand Canyon (North and East Segregation Areas) and one on the Kaibab National Forest south of the Grand Canyon (South Segregation Area). The purpose of the two-year withdrawal is to examine the potential effects of restricting these areas from new mine development for the next 20 years. This proposed withdrawal initiated a period of study during which the effects of the withdrawal must be evaluated. At the direction of the Secretary, the U.S. Geological Survey began a series of short-term studies designed to develop additional information about the possible effects of uranium mining on the natural resources of the region. Dissolved uranium and other major, minor, and trace elements occur naturally in groundwater as the result of precipitation infiltrating from the surface to water-bearing zones and, presumably, to underlying regional aquifers. Discharges from these aquifers occur as seeps and springs throughout the region and provide valuable habitat and water sources for plants and animals. Uranium mining within the watershed may increase the amount of radioactive materials and heavy metals in the surface water and groundwater flowing into Grand Canyon National Park and the Colorado River, and deep mining activities may increase mobilization of uranium through the rock strata into the aquifers. In addition, waste rock and ore from mined areas may be transported away from the mines by wind and runoff.

Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo, Yb and Th) from low-grade uranium ore.

PubMed

Zakrzewska-Koltuniewicz, Grażyna; Herdzik-Koniecko, Irena; Cojocaru, Corneliu; Chajduk, Ewelina

2014-06-30

The paper deals with experimental design and optimization of leaching process of uranium and associated metals from low-grade, Polish ores. The chemical elements of interest for extraction from the ore were U, La, V, Mo, Yb and Th. Sulphuric acid has been used as leaching reagent. Based on the design of experiments the second-order regression models have been constructed to approximate the leaching efficiency of elements. The graphical illustrations using 3-D surface plots have been employed in order to identify the main, quadratic and interaction effects of the factors. The multi-objective optimization method based on desirability approach has been applied in this study. The optimum condition have been determined as P=5 bar, T=120 °C and t=90 min. Under these optimal conditions, the overall extraction performance is 81.43% (for U), 64.24% (for La), 98.38% (for V), 43.69% (for Yb) and 76.89% (for Mo) and 97.00% (for Th). Copyright © 2014 Elsevier B.V. All rights reserved.

RUM JUNGLE PROJECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Australia. Atomic Energy Commission

1963-01-01

A report is presented on the uranium mining and treatment industry established at Rum Jungle and its contribution to the development of the Northern Territory. The Combined Development Agency contract for uranium procurement (terminated in 1963) and some of its results are described. A description of Rum Jungle and its geology and mineralization is given. Mining and treatment of ore are discussed, and some production statistics are given. (D.L.C.)

The role of metasomatism in the balance of halogens in ore-forming process at porphyry Cu-Mo deposits

NASA Astrophysics Data System (ADS)

Berzina, A. N.

2009-04-01

Volatile components play an important role in the evolution of ore-magmatic systems and their ore potential. Of special interest are fluorine and chlorine compounds that principally control the transportation of ore elements by the fluid in a magmatic process and under high-temperature hydrothermal conditions. Study of the evolution of fluorine-chlorine activity in the ore-forming process and their source is usually based on analysis of their magmatic history, whereas the additional source of fluorine and chlorine released during metasomatic alteration of rocks hosting mineralization is poorly discussed in the existing literature. Based on microprobe data on Cl and F abundances in halogen-containing minerals (biotite, amphibole, apatite, titanite) in intrusive rocks and their hydrothermally altered varieties, the role of metasomatic processes in the balance of volatiles in the ore-forming system is discussed by the example of porphyry Cu-Mo deposits of Siberia (Russia) and Mongolia. Two groups of the deposits are considered: copper-molybdenum (Erdenetiin Ovoo, Mongolia and Aksug, Russia) with prevailing propylitic and phyllic alteration and molybdenum-copper (Sora, Russia), with predominant potassic alteration. All types of hydrothermal alterations have led to drastic decrease in Cl contents in metasomatic minerals as compared with halogen-containing magmatic minerals. All studied deposits (particularly those where propylitic and phyllic alteration were developed) show a nearly complete chlorine removal from altered halogen-containing rock-forming minerals (biotite and amphibole). The Cl content in amphibole decreases several times at the stage of replacement with actinolite in the process of propylitization. In the later chlorites (ripidolite and brunsvigite) that replace amphibole, actinolite, and biotite, chlorine is not detected by microprobe (detection limit 0.01-0.02% Cl). Chlorine was also not detected in white micas (muscovite-phengite series) in quartz-sericite alteration zones. No Cl-bearing minerals were revealed in ore-metasomatic assemblages with the exception of extremely low Cl contents in secondary biotite and very rare low-Cl apatite in the early potassic alteration zone. In contrast, fluorine concentrates in chlorites and white micas; however, the F content in them is commonly lower than in dark minerals, especially in biotite from altered rocks. The highest F contents are typical of biotites related to potassic alteration (K-feldspar + biotite + quartz assemblage). For example, the F content at the Sora deposit ranges from 2.5-2.7 wt.% in the metasomatic biotite to 0.44-1.63 wt.% in the rock-forming biotite of host granitoids. At this deposit, fluorite is a major mineral of the ore-metasomatic assemblage. The Mo-rich Sora deposit drastically differs from the Cu-rich Erdenetiin Ovoo and Aksug deposits by extremely low (0.02-0.08 wt.%) Cl contents in dark minerals from all of the host rocks. The considerable quantity of chlorine released as a result of large-scale propylitic and phyllic alteration from halogen-bearing dark minerals at Cu-rich deposits considerably affected the general Cl budget in the ore-metasomatic system. This could significantly promote the generation of Cl-rich (up to 50-70 wt.% NaCl-equiv.) ore-forming solutions at such deposits. At the Sora deposit characterized by less concentrated ore-bearing solutions (12-20 wt.% NaCl-equiv.), the metasomatic alteration of host rocks was not accompanied by an appreciable removal of Cl. At the studied deposits, huge volumes of enclosing rocks were involved in metasomatism. The large amounts of halogens released during the metasomatic alteration of host rocks might have significantly influenced the balance of volatiles in the ore forming system, including the increase in the salinity of hydrothermal solutions.

Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

USGS Publications Warehouse

Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

1999-01-01

The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep-ocean waters, and marine transgression. Water depth increased from deposition of the black phyllite sequence through deposition of the Mn mixed-carbonate sequence, then shallowed again during deposition of the overlying dolostone sequence. Bottom waters were mostly dysoxic to suboxic, but fluctuated from oxic to anoxic. Productivity was high during deposition of the black phyllite sequence, increased during precipitation of phosphorite, and then decreased to moderate levels during precipitation of rhodochrostone ores. Biosilica contributions occur in each lithology, but are greatest in rhodochrostone. Changes in sedimentation were determined by changes in water depth, productivity, upwelling, sea-level change, and ventilation of the depositional basin. The source of the phosphorus was organic matter produced in great quantities during deposition of the black phyllite and phosphorite sequences in a zone of coastal upwelling. Organic matter accumulation was rapid. Globally, Mn was supplied by overturn of stagnant, metal-rich deep-ocean waters, which were redistributed to areas of coastal upwelling and seaways; that process may have been initiated by latest Proterozoic glaciations which would have promoted density stratification and accumulation and storage of metals. Regionally, Mn was supplied by terrigenous input into the shallow seaway and hydrothermal input into the deeper water parts of that seaway. Locally, Mn sources included leaching and transport of metals from the sediment column. Manganese was stored locally in low-oxygen (not anoxic) seawater prior to Mn-ore formation. The source of the carbon in the Mn carbonates and dolostones was predominantly seawater bicarbonate and secondarily CO2 derived from the oxidation of organic matter in the bacterially mediated diagenetic zone of sulfate reduction.

26 CFR 1.617-2 - Limitation on amount deductible.

Code of Federal Regulations, 2011 CFR

2011-04-01

... with respect to any deposit of ore or other mineral for which a deduction for percentage depletion is... expenditures paid or incurred after December 31, 1969, with respect to any deposit of ore or other mineral for... respect to any such deposit in the United States (as defined in section 638 and the regulations thereunder...

Determination of impurities in uranium matrices by time-of-flight ICP-MS using matrix-matched method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buerger, Stefan; Riciputi, Lee R; Bostick, Debra A

2007-01-01

The analysis of impurities in uranium matrices is performed in a variety of fields, e.g. for quality control in the production stream converting uranium ores to fuels, as element signatures in nuclear forensics and safeguards, and for non-proliferation control. We have investigated the capabilities of time-of-flight ICP-MS for the analysis of impurities in uranium matrices using a matrix-matched method. The method was applied to the New Brunswick Laboratory CRM 124(1-7) series. For the seven certified reference materials, an overall precision and accuracy of approximately 5% and 14%, respectively, were obtained for 18 analyzed elements.

The History of Uranium Mining and the Navajo People

PubMed Central

Brugge, Doug; Goble, Rob

2002-01-01

From World War II until 1971, the government was the sole purchaser of uranium ore in the United States. Uranium mining occurred mostly in the southwestern United States and drew many Native Americans and others into work in the mines and mills. Despite a long and well-developed understanding, based on the European experience earlier in the century, that uranium mining led to high rates of lung cancer, few protections were provided for US miners before 1962 and their adoption after that time was slow and incomplete. The resulting high rates of illness among miners led in 1990 to passage of the Radiation Exposure Compensation Act. PMID:12197966

Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland

USGS Publications Warehouse

Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.

1996-01-01

Lead-isotopic data on galena samples collected from a paragenetically constrained suite of samples from the Silesian-Cracow ore district show no regional or paragenetically controlled lead-isotopic trends within the analytical reproducibility of the measurements. Furthermore, the new lead-isotopic data agree with previously reported lead-isotopic results (R. E. Zartman et al., 1979). Sulfur-isotopic analyses of ores from the Silesian-Cracow district as well as from vein ore from the Gory Swietokrzyskie Mts. and the Myszkow porphyry copper deposit, when coupled with trace-element data from the galena samples, clearly discriminate different hydrothermal ore-forming events. Lead-isotopic data from the Permian and Miocene evaporite deposits in Poland indicate that neither of these evaporite deposits were a source of metals for the Silesian-Cracow district ores. Furthermore, lead-isotopic data from these evaporite deposits and the shale residues from the Miocene halite samples indicate that the crustal evolution of lead in the central and western European platform in southern Poland followed normal crustal lead-isotopic growth, and that the isotopic composition of crustal lead had progressed beyond the lead-isotopic composition of lead in the Silesian-Cracow ores by Permian time. Thus, Mesozoic and Tertiary sedimentary flysch rocks can be eliminated as viable source rocks for the metals in the Silesian-Cracow Mississippi Valley-type (MVT) deposits. The uniformity of the isotopic composition of lead in the Silesian-Cracow ores, when coupled with the geologic evidence that mineralization must post-date Late Jurassic faulting (E. Gorecka, 1991), constrains the geochemical nature of the source region. The source of the metals is probably a well-mixed, multi-cycle molasse sequence of sedimentary rocks that contains little if any Precambrian metamorphic or granitic clasts (S. E. Church, R. B. Vaughn, 1992). If ore deposition was post Late Jurassic (about 150 m. y.) or later as indicated by the geologic evidence, the source rocks probably contained elevated concentrations of Zn and Pb (75-100 ppm), and relatively low concentrations of U and Th (2 and 8 ppm or less, respectively). The Carboniferous coal-bearing molasse rocks of the Upper Silesian Coal Basin are a prime candidate for such a source region. The presence of ammonia and acetate in the fluid inclusions (Viets et al., 1996a) also indicate that the Carboniferous coal-bearing molasse sequence in the Upper Silesian Coal Basin may have been a suitable pathway for the MVT ore fluids. The lead-isotopic homogeneity, when coupled with the sulfur-isotopic heterogeneity of the ores suggests that mixing of a single metal-bearing fluid with waters from separate aquifers containing variable sulfur-isotopic compositions in karsts in the Muschelkalk Formation of Middle Triassic age may have been responsible for the precipitation of the ores of the Silesian-Cracow district.

Critical elements in Carlin, epithermal, and orogenic gold deposits

USGS Publications Warehouse

Goldfarb, Richard J.; Hofstra, Albert H.; Simmons, Stuart F.

2016-01-01

Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits.A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then captured in air pollution control devices.

Geologic setting and genesis of the Mule Canyon low-sulfidation epithermal gold-silver deposit, north-central Nevada

USGS Publications Warehouse

John, D.A.; Hofstra, A.H.; Fleck, R.J.; Brummer, J.E.; Saderholm, E.C.

2003-01-01

The Mule Canyon mine exploited shallow, low-sulfidation, epithermal Au-Ag deposits that lie near the west side of the Northern Nevada rift in northern Lander County, Nevada. Mule Canyon consists of six small deposits that contained premining reserves of about 8.2 Mt at an average grade of 3.81 g Au/tonne. It is an uncommon mafic end member of low-sulfidation Au-Ag deposits associated with tholeiitic bimodal basalt-rhyolite magmatism. The ore is hosted by a basalt-andesite eruptive center that formed between about 16.4 to 15.8 Ma during early mafic eruptions related to regionally extensive bimodal magmatism. Hydrothermal alteration and Au-Ag ores formed at about 15.6 Ma and were tightly controlled by north-northwest- to north-striking high-angle fault and breccia zones developed during rifting, emplacement of mafic dikes, and eruption of mafic lava flows. Hydrothermal alteration assemblages are zoned outward from fluid conduits in the sequence silica-adularia, adularia-smectite, smectite (intermediate argillic), and smectite-carbonate (propylitic). All alteration types contain abundant pyrite and/or marcasite ?? arsenopyrite. Field relations indicate that silica-adularia alteration is superimposed on argillic and propylitic alteration. Little or no steam-heated acid-sulfate alteration is present, probably the result of a near-surface water table during hydrothermal alteration and ore deposition. Two distinct ore types are present at Mule Canyon: early replacement and later open-space filling. Replacement ores consist of disseminated and vesicle-filling pyrite, marcasite, and arsenopyrite in argillically altered or weakly silicified rocks. Ore minerals consist of Au-bearing arsenopyrite and arsenian pyrite overgrowths on earlier-formed pyrite and marcasite. Open-space filling ores include narrow stockwork quartz-adularia veins, banded and crustiform opaline and chalcedonic silica-adularia veins, silica-adularia cemented breccias, and sparse carbonate-pyrite and/or marcasite veins. Ore minerals consist mostly of electrum and Ag sulfide and selenide minerals, with minor to major amounts of pyrite, marcasite, and arsenopyrite, and local stibnite. Both types of ores have similar geochemical signatures, characterized by high Au, Ag, As, Sb, and Se contents, locally high Hg, Mo, Tl, and W contents, and low Cu, Pb, and Zn contents. Stable isotope data indicate that ore fluids consisted dominantly of meteoric water that evolved by deep circulation through Paleozoic sedimentary rocks at low water/rock ratios (about 1) and high temperatures (>200??C). Calculated isotopic compositions of ore fluids are ??18OH2O = -3 to -7 per mil, ??DH2O = -107 to -124 per mil, ??13CCO2 = 0 to -6 per mil, and ??34SH2S = -3 to +8 per mil. The ore fluids obtained much of their H2S and CO2 and probably scavenged ore metals and trace elements from the Paleozoic sedimentary rocks. Some H2S and CO2 may have been derived from degassing Miocene magmas. Mule Canyon formed at shallow depths, probably about 100 m below the paleosurface. Ore fluids were dilute, nearly neutral in pH, reduced, H2S-rich, and CO2-bearing. Peak temperatures in ore zones reached 230?? to 265??C at nearly lithostatic pressures when some crystalline quartz ?? adularia precipitated, but most ore formed at temperatures <200??C at near hydrostatic pressures and was accompanied by precipitation of opaline and chalcedonic silica ?? adularia ?? calcite and dolomite. Deposition of gold in As-rich overgrowths on pyrite and/or marcasite in disseminated ores occurred owing to decreasing H2S in the ore fluids resulting from sulfidation reactions. Later electrum and Ag selenide precipitation in open spaces occurred owing to boiling, loss of H2S to the vapor phase, and cooling. Mule Canyon is similar to most other low-sulfidation Au-Ag deposits associated with Miocene tholeiitic bimodal basalt-rhyolite magmatism in the Great Basin, such as Sleeper, Midas, and Buckhorn. Major differences at Mule Canyon are

The role of magmas in the formation of hydrothermal ore deposits

USGS Publications Warehouse

Hedenquist, Jeffrey W.; Lowenstern, Jacob B.

1994-01-01

Magmatic fluids, both vapour and hypersaline liquid, are a primary source of many components in hydrothermal ore deposits formed in volcanic arcs. These components, including metals and their ligands, become concentrated in magmas in various ways from various sources, including subducted oceanic crust. Leaching of rocks also contributes components to the hydrothermal fluid—a process enhanced where acid magmatic vapours are absorbed by deeply circulating meteoric waters. Advances in understanding the hydrothermal systems that formed these ore deposits have come from the study of their active equivalents, represented at the surface by hot springs and volcanic fumaroles.

Biotechnology for the extractive metals industries

NASA Astrophysics Data System (ADS)

Brierley, James A.

1990-01-01

Biotechnology is an alternative process for the extraction of metals, the beneficiation of ores, and the recovery of metals from aqueous systems. Currently, microbial-based processes are used for leaching copper and uranium, enhancing the recovery of gold from refractory ores, and treating industrial wastewater to recover metal values. Future developments, emanating from fundamental and applied research and advances through genetic engineering, are expected to increase the use and efficiency of these biotechnological processes.

Variscan ore formation and metamorphism at the Felbertal scheelite deposit (Austria): constraining tungsten mineralisation from Re-Os dating of molybdenite

NASA Astrophysics Data System (ADS)

Raith, Johann G.; Stein, Holly J.

2006-10-01

The Felbertal scheelite deposit in the Eastern Alps has been regarded as the type locality for stratabound scheelite deposits. It is hosted by a Cambro-Ordovician metavolcanic arc sequence with minor Variscan granitoids (˜ 340 Ma) in the central Tauern Window. Re-Os model ages for molybdenite from the Felbertal tungsten deposit range between ˜ 358 and ˜ 336 Ma and record several pulses of magmatic-hydrothermal-metamorphic molybdenite formation. Molybdenite ages from the K2 orebody, a scheelite-rich quartz mylonite in the Western ore field, indicate that both mineralisation and mylonite are Variscan in age and suggest that the shear zone was active for ˜ 20 million years. Early stage tungsten mineralisation ( Scheelite 1) in quartzitic ores in the Eastern ore field, which is free of molybdenite, yielded very low to near blank levels of Re and Os and thus could not be dated. However, molybdenite from scheelite-quartz stringers, previously interpreted as a feeder stockwork to quartzitic scheelite ore of presumed Cambrian age, yielded Variscan Re-Os ages of ˜ 342 and ˜ 337 Ma. Dating of molybdenite contained in scheelite ores thus far provides no indication of a Cambrian component to the tungsten mineralisation. Our data are consistent with a model of either granite intrusion-related ore formation and coeval metamorphic overprint during the Early Carboniferous or, alternatively, molybdenite formation may be exclusively attributed to Variscan metamorphism (see Stein 2006).

Contrasting hydrological processes of meteoric water incursion during magmatic-hydrothermal ore deposition: An oxygen isotope study by ion microprobe

NASA Astrophysics Data System (ADS)

Fekete, Szandra; Weis, Philipp; Driesner, Thomas; Bouvier, Anne-Sophie; Baumgartner, Lukas; Heinrich, Christoph A.

2016-10-01

Meteoric water convection has long been recognized as an efficient means to cool magmatic intrusions in the Earth's upper crust. This interplay between magmatic and hydrothermal activity thus exerts a primary control on the structure and evolution of volcanic, geothermal and ore-forming systems. Incursion of meteoric water into magmatic-hydrothermal systems has been linked to tin ore deposition in granitic plutons. In contrast, evidence from porphyry copper ore deposits suggests that crystallizing subvolcanic magma bodies are only affected by meteoric water incursion in peripheral zones and during late post-ore stages. We apply high-resolution secondary ion mass spectrometry (SIMS) to analyze oxygen isotope ratios of individual growth zones in vein quartz crystals, imaged by cathodo-luminescence microscopy (SEM-CL). Existing microthermometric information from fluid inclusions enables calculation of the oxygen isotope composition of the fluid from which the quartz precipitated, constraining the relative timing of meteoric water input into these two different settings. Our results confirm that incursion of meteoric water directly contributes to cooling of shallow granitic plutons and plays a key role in concurrent tin mineralization. By contrast, data from two porphyry copper deposits suggest that downward circulating meteoric water is counteracted by up-flowing hot magmatic fluids. Our data show that porphyry copper ore deposition occurs close to a magmatic-meteoric water interface, rather than in a purely magmatic fluid plume, confirming recent hydrological modeling. On a larger scale, the expulsion of magmatic fluids against the meteoric water interface can shield plutons from rapid convective cooling, which may aid the build-up of large magma chambers required for porphyry copper ore formation.

Physical and chemical controls on ore shoots - insights from 3D modeling of an orogenic gold deposit

NASA Astrophysics Data System (ADS)

Vollgger, S. A.; Tomkins, A. G.; Micklethwaite, S.; Cruden, A. R.; Wilson, C. J. L.

2016-12-01

Many ore deposits have irregular grade distributions with localized elongate and well-mineralized rock volumes commonly referred to as ore shoots. The chemical and physical processes that control ore shoot formation are rarely understood, although transient episodes of elevated permeability are thought to be important within the brittle and brittle-ductile crust, due to faulting and fracturing associated with earthquake-aftershock sequences or earthquake swarms. We present data from an orogenic gold deposit in Australia where the bulk of the gold is contained in abundant fine arsenopyrite crystals associated with a fault-vein network within tight upright folds. The deposit-scale fault network is connected to a deeper network of thrust faults (tens of kilometers long). Using 3D implicit modeling of geochemical data, based on radial basis functions, gold grades and gold-arsenic element ratios were interpolated and related to major faults, vein networks and late intrusions. Additionally, downhole bedding measurements were used to model first order (mine-scale) fold structures. The results show that ore shoot plunges are not parallel with mine-scale or regional fold plunges, and that bedding parallel faults related to flexural slip folding play a pivotal role on ore shoot attitudes. 3D fault slip and dilation tendency analysis indicate that fault reactivation and formation of linking faults are associated with large volumes of high-grade ore. We suggest slip events on the large-scale thrust network allowed mineralizing fluids to rapidly migrate over large distances and become supersaturated in elements such as gold, promoting widespread precipitation and high nucleation densities of arsenopyrite upon fluid-rock interaction at trap sites within the deposit.

Uranium(IV) adsorption by natural organic matter in anoxic sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bone, Sharon E.; Dynes, James J.; Cliff, John

Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO 2+x) in anoxic sediments; however, studies now show that this is not often the case. Yet a model of U(IV) speciation in the absence of mineral formation under field-relevant conditions has not yetmore » been developed. Uranium(IV) speciation controls its reactivity, particularly its susceptibility to oxidative mobilization, impacting its distribution and toxicity. Here we show adsorption to organic carbon and organic carbon-coated clays dominate U(IV) speciation in an organic-rich natural substrate under field-relevant conditions. Whereas previous research assumed that U(IV) speciation is dictated by the mode of reduction (i.e., whether reduction is mediated by microbes or by inorganic reductants), our results demonstrate that mineral formation can be diminished in favor of adsorption, regardless of reduction pathway. Projections of U transport and bioavailability, and thus its threat to human and ecosystem health, must consider U(IV) adsorption to organic matter within the sediment environment.« less

Uranium(IV) adsorption by natural organic matter in anoxic sediments

DOE PAGES

Bone, Sharon E.; Dynes, James J.; Cliff, John; ...

2017-01-09

Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO 2+x) in anoxic sediments; however, studies now show that this is not often the case. Yet a model of U(IV) speciation in the absence of mineral formation under field-relevant conditions has not yetmore » been developed. Uranium(IV) speciation controls its reactivity, particularly its susceptibility to oxidative mobilization, impacting its distribution and toxicity. Here we show adsorption to organic carbon and organic carbon-coated clays dominate U(IV) speciation in an organic-rich natural substrate under field-relevant conditions. Whereas previous research assumed that U(IV) speciation is dictated by the mode of reduction (i.e., whether reduction is mediated by microbes or by inorganic reductants), our results demonstrate that mineral formation can be diminished in favor of adsorption, regardless of reduction pathway. Projections of U transport and bioavailability, and thus its threat to human and ecosystem health, must consider U(IV) adsorption to organic matter within the sediment environment.« less

Crystal chemistry of pyrochlore from the Mesozoic Panda Hill carbonatite deposit, western Tanzania

NASA Astrophysics Data System (ADS)

Boniface, Nelson

2017-02-01

The Mesozoic Panda Hill carbonatite deposit in western Tanzania hosts pyrochlore, an ore and source of niobium. This study was conducted to establish the contents of radioactive elements (uranium and thorium) in pyrochlore along with the concentration of niobium in the ore. The pyrochlore is mainly hosted in sövite and is structurally controlled by NW-SE (SW dipping) or NE-SW (NW dipping) magmatic flow bands with dip angles of between 60° and 90°. Higher concentrations of pyrochlore are associated with magnetite, apatite and/or phlogopite rich flow bands. Electron microprobe analyses on single crystals of pyrochlore yield very low UO2 concentrations that range between 0 and 0.09 wt% (equivalent to 0 atoms per formula unit: a.p.f.u.) and ThO2 between 0.55 and 1.05 wt% (equivalent to 0.1 a.p.f.u.). The analyses reveal high concentrations of Nb2O5 (ranging between 57.13 and 65.50 wt%, equivalent to a.p.f.u. ranging between 1.33 and 1.43) and therefore the Panda Hill Nb-oxide is classified as pyrochlore sensu stricto. These data point to a non radioactive pyrochlore and a deposit rich in Nb at Panda Hill. The Panda Hill pyrochlore has low concentrations of REEs as displayed by La2O3 that range between 0.10 and 0.49 wt% (equivalent to a.p.f.u. ranging between 0 and 0.01) and Ce2O3 ranging between 0.86 and 1.80 wt% (equivalent to a.p.f.u. ranging between 0.02 and 0.03), Pr2O3 concentrations range between 0 and 0.23 wt% (equivalent to 0 a.p.f.u.), and Y2O3 is 0 wt% (equivalent to 0 a.p.f.u.). The abundance of the REEs in pyroclore at the Panda Hill Carbonatite deposit is of no economic significance.

A deposit model for Mississippi Valley-Type lead-zinc ores: Chapter A in Mineral deposit models for resource assessment

USGS Publications Warehouse

Leach, David L.; Taylor, Ryan D.; Fey, David L.; Diehl, Sharon F.; Saltus, Richard W.

2010-01-01

This report also describes the geoenvironmental characteristic of MVT deposits. The response of MVT ores in the supergene environment is buffered by their placement in carbonate host rocks which commonly results in near-neutral associated drainage water. The geoenvironmental features and anthropogenic mining effects presented in this report illustrates this important environmental aspect of MVT deposits which separates them from other deposit types (especially coal, VHMS, Cu-porphyry, SEDEX, acid-sulfate polymetallic vein).

Origin of high-grade gold ore, source of ore fluid components, and genesis of the Meikle and neighboring Carlin-type deposits, Northern Carlin Trend, Nevada

USGS Publications Warehouse

Emsbo, P.; Hofstra, A.H.; Lauha, E.A.; Griffin, G.L.; Hutchinson, R.W.

2003-01-01

The Meikle mine exploits one of the world's highest grade Carlin-type gold deposits with reserves of ca. 220 t gold at an average grade of 24.7 g/t. Locally, gold grades exceed 400 g/t. Several geologic events converged at Meikle to create these spectacular gold grades. Prior to mineralization, a Devonian hydrothermal system altered the Bootstrap limestone to Fe-rich dolomite. Subsequently the rocks were brecciated by faulting and Late Jurassic intrusive activity. The resulting permeability focused flow of late Eocene Carlin-type ore fluids and allowed them to react with the Fe-rich dolomite. Fluid inclusion data and mineral assemblages indicate that these fluids were hot (ca. 220??C),of moderate salinity (400 g/t. Petrographic observations, geochemical data, and stable isotope results from the Meikle mine and other deposits at the Goldstrike mine place important constraints on genetic models for Meikle and other Carlin-type gold deposits on the northern Carlin trend. The ore fluids were meteoric water (??D = -135???, ??18O = -5???) that interacted with sedimentary rocks at a water/rock ratio of ca. 1 and temperatures of ca. 220??C. The absence of significant silicification suggests that there was little cooling of the ore fluids during mineralization. These two observations strongly suggest that ore fluids were not derived from deep sources but instead flowed parallel to isotherms. The gold was transported by H2S (??34S = 9???), which was derived from Paleozoic sedimentary rocks. The presence of auriferous sedimentary exhalative mineralization in the local stratigraphic sequence raises the possibility that preexisting concentrations of gold contributed to the Carlin-type deposits. Taken together our observations suggest that meteoric water evolved to become an ore fluid by shallow circulation through previously gold- and sulfur-enriched rocks. Carlin-type gold deposits formed where these fluids encountered permeable, reactive Fe-rich rocks.

Dzhezkazgan and associated sandstone copper deposits of the Chu-Sarysu basin, Central Kazakhstan

USGS Publications Warehouse

Box, Stephen E.; Seltmann, Reimar; Zientek, Michael L.; Syusyura, Boris; Creaser, Robert A.; Dolgopolova, Alla

2012-01-01

Sandstone-hosted copper (sandstone Cu) deposits occur within a 200-km reach of the northern Chu-Sarysu basin of central Kazakhstan (Dzhezkazgan and Zhaman-Aibat deposits, and the Zhilandy group of deposits). The deposits consist of Cu sulfide minerals as intergranular cement and grain replacement in 10 ore-bearing members of sandstone and conglomerate within a 600- to 1,000-m thick Pennsylvanian fluvial red-bed sequence. Copper metal content of the deposits ranges from 22 million metric tons (Mt, Dzehzkazgan) to 0.13Mt (Karashoshak in the Zhilandy group), with average grades of 0.85 to 1.7% Cu and significant values for silver (Ag) and rhenium (Re). Broader zones of iron reduction (bleaching) of sandstones and conglomerates of the red-bed sequence extend over 10 km beyond each of the deposits along E-NE-trending anticlines, which began to form in the Pennsylvanian. The bleached zones and organic residues within them are remnants of ormer petroleum fluid accumulations trapped by these anticlines. Deposit sites along these F1anticlines are localized at and adjacent to the intersections of nearly orthogonal N-NW-trending F2synclines. These structural lows served to guide the flow of dense ore brines across the petroleum-bearing anticlines, resulting in ore sulfide precipitation where the two fluids mixed. The ore brine was sourced either from the overlying Early Permian lacustrine evaporitic basin, whose depocenter occurs between the major deposits, or from underlying Upper Devonian marine evaporites. Sulfur isotopes indicate biologic reduction of sulfate but do not resolve whether the sulfate was contributed from the brine or from the petroleum fluids. New Re-Os age dates of Cu sulfides from the Dzhezkazgan deposit indicate that mineralization took place between 299 to 309 Ma near the Pennsylvanian-Permian age boundary. At the Dzhezkazgan and some Zhilandy deposits, F2fold deformation continued after ore deposition. Copper orebodies in Lower Permian shale near the Zhaman-Aibat deposit indicate that at least some of the mineralization there is younger than at Dzhezkazgan, consistent with the Re-Os age and with differences in their ore Pb isotopes.

Application of the Geo-Anomaly Unit Concept in Quantitative Delineation and Assessment of Gold Ore Targets in Western Shandong Uplift Terrain, Eastern China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen Yongqing, E-mail: ydonglai@mail.cgs.gov.cn; Zhao Pengda; Chen Jianguo

2001-03-15

A number of large and giant ore deposits have been discovered within the relatively small areas of lithospheric structure anomalies, including various boundary zones of tectonic plates. The regions have become the well-known intercontinental ore-forming belts, such as the circum-Pacific gold-copper, copper-molybdenum, and tungsten-tin metallogenic belts. These belts are typical geological anomalous areas. An investigation into the hydrothermal ore deposits in different regions in the former Soviet Union illustrated that the geologic structures of ore fields of almost all major commercial deposits have distinct features compared with the neighboring areas. These areas with distinct features are defined as geo-anomalies. Amore » geo-anomaly refers to such a geologic body or a combination of bodies that their composition, texture-structure, and genesis are significantly different from those of their surroundings. A geo-anomaly unit (GU) is an area containing distinct features that can be delineated with integrated ore-forming information using computer techniques on the basis of the geo-anomaly concept. Herein, the GU concept is illustrated by a case study of delineating the gold ore targets in the western Shandong uplift terrain, eastern China. It includes: (1) analyses of gold ore-forming factors; (2) compilation of normalized regional geochemical map and extraction of geochemical anomalies; (3) compilation of gravitational and aeromagnetic tectonic skeleton map and extraction of gravitational and aeromagnetic anomalies; (4) extraction of circular and linear anomalies from remote-sensing Landsat TM images; (5) establishment of a geo-anomaly conceptual model associated with known gold mineralization; (6) establishment of gold ore-forming favorability by computing techniques; and (7) delineation and assessment of ore-forming units. The units with high favorability are suggested as ore targets.« less

Gold paragenesis and chemistry at Batu Hijau, Indoneisa: implications for gold-rich porphyry copper deposits

NASA Astrophysics Data System (ADS)

Arif, J.; Baker, T.

2004-10-01

Gold is an important by-product in many porphyry-type deposits but the distribution and chemistry of gold in such systems remains poorly understood. Here we report the results of petrographic, electron microprobe, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and flotation test studies of gold and associated copper sulfides within a paragenetic framework from the world-class Batu Hijau (914 mt @ 0.53% Cu, 0.40 g/t Au) porphyry copper gold deposit, Indonesia. Unlike many other porphyry copper gold deposits, early copper minerals (bornite digenite chalcocite) are well preserved at Batu Hijau and the chalcopyrite pyrite overprint is less developed. Hence, it provides an excellent opportunity to study the entire gold paragenesis of the porphyry system. In 105 polished thin sections, 699 native gold grains were identified. Almost all of the native gold grains occurred either within quartz veins, attached to sulfide, or as free gold along quartz or silicate grain boundaries. The native gold grains are dominantly round in shape and mostly 1 12 μm in size. The majority of gold was deposited during the formation of early ‘A’ veins and is dominantly associated with bornite rather than chalcopyrite. The petrographic and LA-ICP-MS study results indicate that in bornite-rich ores gold mostly occurs within copper sulfide grains as invisible gold (i.e., within the sulfide structure) or as native gold grains. In chalcopyrite-rich ores gold mostly occurs as native gold grains with lesser invisible gold. Petrographic observations also indicate a higher proportion of free gold (native gold not attached to any sulfide) in chalcopyrite-rich ores compared to bornite rich ores. The pattern of free gold distribution appears to correlate with the flotation test data, where the average gold recovery value from chalcopyrite-rich ores is consistently lower than bornite-rich ores. Our data suggest that porphyry copper-gold deposits with chalcopyrite-rich ores are more likely to have a higher proportion of free gold and may require different ore processing strategies.

The role of ophiolite in metallogeny of the Sikhote-Alin region

NASA Astrophysics Data System (ADS)

Kazachenko, V. T.; Perevoznikova, E. V.; Lavrik, S. N.; Skosareva, N. V.

2012-06-01

Metalliferous sediments of the Triassic siliceous formation of the Sikhote-Alin (manganese-silicate rocks and cherts with dispersed rhodochrosite, silicate-magnetite ores, and jasper) and skarns of the Dalnegorsk and Olginsk ore districts were initially the wash away products (Late Anisian-end of the Triassic) of the lateritic weathering crust on ophiolite in the islands. Manganese, iron, and other metals were deposited in the sediments of both lagoons (present-day, skarns) and island water areas (manganese-silicate and siliceousrhodochrosite rocks, silicate-magnetite ores, and jasper). Skarns contain boric and polymetallic ores thus indicating the occurrence of both shallow (periodically drying up) and quite deep (with hydrogen sulfide contamination zones) lagoons. Lead was deposited in protoliths of the skarn deposits in lagoons from the beginning of the Carboniferous to the beginning of the Late Anisian (initial island submergence). Tin, tin-leadzinc (with Ag), and silver-lead-zinc (with Sn and Au) vein deposits (Late Cretaceous-Paleogene) of the Taukha and Zhuravlevka Terrains contain lead deposited in the sediments flanking the islands of water areas with the hydrogen sulfide contamination zones, in the Carboniferous-Permian and Triassic metalliferous sediments.

Analysis of variance in investigations on anisotropy of Cu ore deposits

NASA Astrophysics Data System (ADS)

Namysłowska-Wilczyńska, B.

1986-10-01

The problem of variability of copper grades and ore thickness in the Lubin copper ore deposit in southwestern Poland is presented. Results of statistical analysis of variations of ledge parameters carried out for three exploited regions of the mine, representing different types of lithological profile show considerable differences. Variability of copper grades occurs in vertical profiles, as well as on extension of field (the copper-bearing series). Against the background of a complex, well-substantiated description of the spatial variability in the Lubin deposit, a methodology is presented that has been applied for the determination of homogeneous ore blocks. The method is a two-factorial (cross) analysis of variance with the special tests of Tukey, Scheffe and Duncan. Blocks of homogeneous sandstone ore have dimensions of up to 160,000 m2 and 60,000 m2 in the case of the Cu content parameter and 200,000 m2 and 10,000 m2 for the thickness parameter.

Uranium in bone: metabolic and autoradiographic studies in the rat.

PubMed

Priest, N D; Howells, G R; Green, D; Haines, J W

1982-03-01

The distribution and retention of intravenously injected hexavalent uranium-233 in the skeleton of the female rat has been investigated using a variety of autoradiographic and radiochemical techniques. These showed that approximately one third of the injected uranium is deposited in the skeleton where it is retained with an initial biological half-time of approximately 40 days. The studies also showed that: 1 Uranium is initially deposited onto all types of bone surface, but preferentially onto those that are accreting. 2 Uranium is deposited in the calcifying zones of skeletal cartilage. 3 Bone accretion results in the burial of surface deposits of uranium. 4 Bone resorption causes the removal of uranium from surfaces. 5 Resorbed uranium is not retained by osteoclasts and macrophages in the bone marrow. 6 Uranium removed from bone surfaces enters the bloodstream where most is either redeposited in bone or excreted via the kidneys. 7 The recycling of resorbed uranium within the skeleton tends to produce a uniform level of uranium contamination throughout mineralized bone. These results are taken to indicate that uranium deposition in bone shares characteristics in common with both the 'volume-seeking radionuclides' typified by the alkaline earth elements and with the 'bone surface-seeking radionuclides' typified by plutonium.

Tourmaline in Appalachian - Caledonian massive sulphide deposits and its exploration significance.

USGS Publications Warehouse

Slack, J.F.

1982-01-01

Tourmaline is a common gangue mineral in several types of stratabound mineral deposits, including some massive base-metal sulphide ores of the Appalachian - Caledonian orogen. It is most abundant (sometimes forming massive foliated tourmalinite) in sediment-hosted deposits, such as those at the Elizabeth Cu mine and the Ore Knob Cu mine (North Carolina, USA). Trace amounts of tourmaline occur associated with volcanic-hosted deposits in the Piedmont and New England and also in the Trondheim district. Tourmaline associated with the massive sulphide deposits are Mg- rich dravites with major- and trace-element compositions significantly different from schorl. It is suggested that the necessary B was produced by submarine exhalative processes as a part of the same hydrothermal system that deposited the ores. An abundance of dravite in non-evaporitic terrains is believed to indicate proximity to former subaqueous fumarolic centres.-R.A.H.

MetClass: A software for the visualization and exploitation of Dill's (2010) "chessboard" classification of mineral deposits

NASA Astrophysics Data System (ADS)

Kaabeche, Hamza; Chabou, Moulley Charaf; Bendaoud, Abderrahmane; Bodinier, Jean-Louis; Lobry, Olivier; Retif, Fabien

2016-06-01

Rising economic value of a large number of metals as a result of their importance for new technologies and industrial development has renewed worldwide interest for mineral exploration and detailed studies of ore deposits. The Dill's (2010) "chessboard" classification of mineral deposits is the most recent attempt to provide an exhaustive overview of all mineral deposits known to date. However, the voluminous Dills review paper is accessible only in print or as PDF file. In this article, we present MetClass, software that provides advanced solutions to perform efficient research and statistics using Dill's classification and the related database. MetClass allows to assemble all results relevant to a given ore deposit on a user-friendly interface. This software is therefore a valuable tool for mineral exploration and research on ore deposits, as well as an educational solution for students in metallogeny.

Zircon U-Pb geochronology and geochemistry of granites in the Zhuguangshan complex, South China: Implications for uranium mineralization

NASA Astrophysics Data System (ADS)

Zhang, Long; Chen, Zhenyu; Li, Xiaofeng; Li, Shengrong; Santosh, M.; Huang, Guolong

2018-05-01

The Zhuguangshan complex, composed of Caledonian, Indosinian, and Yanshanian granites, and Cretaceous mafic dykes, is one of the most important granite-hosted uranium producers in South China. Here we present LA-ICP-MS zircon U-Pb and hornblende 40Ar/39Ar geochronology and whole-rock and biotite geochemistry for the granites in this complex to evaluate the magmatism and its constraints on uranium mineralization. Samples collected from the Fuxi, Youdong, Longhuashan, Chikeng, Qiling, and Sanjiangkou intrusions yield zircon weighted 206Pb/238U ages of 426.7 ± 5.4 Ma, 226.4 ± 3.5 Ma, 225.0 ± 2.7 Ma, 152.2 ± 3.0 Ma, 153.9 ± 2.1 Ma, and 155.2 ± 2.1 Ma, respectively. A new Ar-Ar dating of the hornblende of the diabase from the Changjiang uranium ore field yields a plateau age of 145.1 ± 1.5 Ma. These results coupled with published geochronological data indicate that six major magmatic events occurred in the study area at 420-435 Ma, 225-240 Ma, 150-165 Ma, 140 Ma, 105 Ma, and 90 Ma. Both U-bearing and barren granites occur in this complex, and they display differences in whole-rock and biotite geochemistry. The barren granites show higher Al2O3, CaO, TFMM, Rb, Zr, Ba, SI, Mg#, (La/Yb)N, and Eu/Eu*, but lower SiO2, ALK, Rb, DI, Rb/Sr, and TiO2/MgO than those of the U-bearing granites. Biotites in the U-bearing granites are close to the Fe-rich siderophyllite-annite end member with Fe/(Fe + Mg) ratios higher than 0.66, whereas those in the barren granites are relatively close to the Mg-rich eastonite-phlogopite end member with Fe/(Fe + Mg) ratios <0.66. The U-bearing granites were mainly derived from the partial melting of pelitic sedimentary source, whereas the psammitic source generated the barren granites. In addition, the barren granites show higher TFMM, Ba, and Eu/Eu* but lower SiO2, Rb/Sr and Al2O3/TiO2 ratios with higher zircon saturation temperatures relative to the U-bearing granites. These results indicate that the geochemical compositions of the U-bearing and barren granites are dictated not only by the compositions of source rocks but also the physicochemical conditions of partial melting. Our study suggests that these two factors are also the major factors that control uranium ore potential of the granites in the Zhuguangshan complex. The geochemical variations of U-bearing and barren granites can serve as a potential detector for granite-hosted uranium deposits.

A reinterpretation of the δDH2O of inclusion fluids in contemporaneous quartz and sphalerite, Creede mining district, Colorodo: a generic problem for shallow orebodies?

USGS Publications Warehouse

Foley, Nora K.; Bethke, Philip M.; Rye, Robert O.

1989-01-01

The unusually high contrast between the salinities of the ore-depositing fluids and the ground water overlying the ore zone allowed recognition of this phenomenon at Creede. It is likely, however, that Creede is not unique. Similar phenomena may be common in shallow ore zones where rapid fluctuation of an interface between a deep, high-temperature thermal plume and an overlying, cooler ground water may be expected to occur. Careful study of the origins of fluid inclusions, particularly in quartz, is essential to characterize the primary ore fluids and to assess the role of ground water in the hydrology of shallow ore deposits.

The Krásná Hora, Milešov, and Příčovy Sb-Au ore deposits, Bohemian Massif: mineralogy, fluid inclusions, and stable isotope constraints on the deposit formation

NASA Astrophysics Data System (ADS)

Němec, Matěj; Zachariáš, Jiří

2018-02-01

The Krásná Hora-Milešov and Příčovy districts (Czech Republic) are the unique examples of Sb-Au subtype orogenic gold deposits in the Bohemian Massif. They are represented by quartz-stibnite veins and massive stibnite lenses grading into low-grade, disseminated ores in altered host rocks. Gold postdates the stibnite and is often replaced by aurostibite. The ore zones are hosted by hydrothermally altered dikes of lamprophyres (Krásná Hora-Milešov) or are associated with local strike-slip faults (Příčovy). Formation of Sb-Au deposits probably occurred shortly after the main gold-bearing event (348-338 Ma; Au-only deposits) in the central part of the Bohemian Massif. Fluid inclusion analyses suggest that stibnite precipitated at 250 to 130 °C and gold at 200 to 130 °C from low-salinity aqueous fluids. The main quartz gangue hosting the ore precipitated from the same type of fluid at about 300 °C. Early quartz-arsenopyrite veins are not associated with the Sb-Au deposition and formed from low-salinity, aqueous-carbonic fluid at higher pressure and temperature ( 250 MPa, 400 °C). The estimated oxygen isotope composition of the ore-bearing fluid (4 ± 1‰ SMOW; based on post-ore calcite) suggests its metamorphic or mixed magmatic-metamorphic origin and excludes the involvement of meteoric water. Rapid cooling of warm hydrothermal fluids reacting with "cold" host rock was probably the most important factor in the formation of both stibnite and gold.

New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

USGS Publications Warehouse

Carmichael, Sarah K.; Doctor, Daniel H.; Wilson, Crystal G.; Feierstein, Joshua; McAleer, Ryan J.

2017-01-01

Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace and rare earth element (REE) geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered alluvial deposits that occur close to breccia-hosted Mn deposits in Virginia show geochemical signatures that are distinct from the breccia matrices and appear to reflect remobilization of earlier-emplaced Mn and concentration within supergene traps. Based on the proximity of all of the productive ore deposits to mapped faults or other zones of deformation, we suggest that the primary source of all of the Mn may have been deep seated, and that Mn oxides with supergene and/or biological characteristics resulted from the local remobilization and concentration of this primary Mn.

Lead in the Getchell-Turquoise ridge Carlin-type gold deposits from the perspective of potential igneous and sedimentary rock sources in Northern Nevada: Implications for fluid and metal sources

USGS Publications Warehouse

Tosdal, R.M.; Cline, J.S.; Fanning, C.M.; Wooden, J.L.

2003-01-01

Lead isotope compositions of bulk mineral samples (fluorite, orpiment, and realgar) determined using conventional techniques and of ore-stage arsenian pyrite using the Sensitive High Resolution Ion-Microprobe (SHRIMP) in the Getchell and Turquoise Ridge Carlin-type gold deposits (Osgood Mountains) require contribution from two different Pb sources. One Pb source dominates the ore stage. It has a limited Pb isotope range characterized by 208Pb/206Pb values of 2.000 to 2.005 and 207Pb/206Pb values of 0.8031 to 0.8075, as recorded by 10-??m-diameter spot SHRIMP analyses of ore-stage arsenian pyrite. These values approximately correspond to 206Pb/204Pb of 19.3 to 19.6, 207Pb/204Pb of 15.65 to 15.75, and 208Pb/204Pb of 39.2 to 39.5. This Pb source is isotopically similar to that in average Neoproterozoic and Cambrian elastic rocks but not to any potential magmatic sources. Whether those clastic rocks provided Pb to the ore fluid cannot be unequivocally proven because their Pb isotope compositions over the same range as in ore-stage arsenian pyrite are similar to those of Ordovician to Devonian siliciclastic and calcareous rocks. The Pb source in the calcareous rocks most likely is largely detrital minerals, since that detritus was derived from the same sources as the detritus in the Neoproterozoic and Cambrian clastic rocks. The second Pb source is characterized by a large range of 206Pb/204Pb values (18-34) with a limited range of 208Pb/204Pb values (38.1-39.5), indicating low but variable Th/U and high and variable U/Pb values. The second Pb source dominates late and postore-stage minerals but is also found in preore sulfide minerals. These Pb isotope characteristics typify Ordovician to Devonian siliciclastic and calcareous rocks around the Carlin trend in northeast Nevada. Petrologically similar rocks host the Getchell and Turquoise Ridge deposits. Lead from the second source was either contributed from the host sedimentary rock sequences or brought into the hydrothermal system by oxidized ground water as the system collapsed. Late ore- and postore-stage sulfide minerals (pyrite, orpiment, and stibnite) from the Betze-Post and Meikle deposits in the Carlin trend and from the Jerritt Canyon mining district have Pb isotope characteristics similar to those determined in Getchell and Turquoise Ridge. This observation suggests that the Pb isotope compositions of their ore fluids may be similar to those at Getchell and Turquoise Ridge. Two models can explain the Pb isotope compositions of the ore-stage arsenian pyrite versus the late ore or postore sulfide minerals. In either model, Pb from the Ordovician to Devonian siliciclastic and calcareous rock source enters the hydrothermal system late in the ore stage but not to any extent during the main stage of ore deposition. In one model, ore-stage Pb was derived from a source with Pb isotope compositions similar to those of the Neoproterozoic and Cambrian clastic sequence, transported as part of the ore fluid and then deposited in the ore-stage arsenian pyrite and fluorite. The second model is based on the observation that the Pb isotope characteristics of the ore-stage minerals also are found in some Ordovician to Devonian calcareous and siliciclastic rocks. Hence, ore-stage Pb could have been derived locally and simply concentrated during the ore stage. Critical to the second model is the removal of all high 206Pb/204Pb (>20) material during alteration. It Also requires the retention of only the low 206Pb/204Pb component of the Ordovician to Devonian sedimentary rocks. This critical step is possible only if the high 206Pb/204Pb values are contained in readily dissolvable mineral phases, whereas the low 206Pb/204Pb values are found only in refractory minerals that released Pb during a final alteration stage just prior deposition of auriferous arsenian pyrite. Distinguishing between Pb transported with the ore fluid or inherited from the site of mineral deposition is not straightforward

Reconnaissance of uranium and copper deposits in parts of New Mexico, Colorado, Utah, Idaho, and Wyoming

USGS Publications Warehouse

Gott, Garland B.; Erickson, Ralph L.

1952-01-01

Because of the common association of uranium and copper in several of the commercial uranium deposits in the Colorado Plateau Province, a reconnaissance was made of several known deposits of copper disseminated through sandstone to determine whether they might be a source of uranium. In order to obtain more information regarding the relationship between copper, uranium and carbonaceous materials, some of the uraniferious asphaltrite deposits in the Shinarump conglomerate along the west flank of the San Rafael Swell were also investigated briefly. During this reconnaissance 18 deposits were examined in New Mexico, eight in Utah, two in Idaho, and one each in Wyoming and Colorado. No uranium deposits of commercial grade are associated with the copper deposits that were examined. The uraniferous asphaltites in the Shinarump conglomerate of Triassic age on the west flank of the San Rafael Swell, however, are promising from the standpoint of commercial uranium production. Spectrographic analyses of crude oil, asphalt, and bituminous shales show a rather consistent suite of trace metals including vanadium, nickel, copper, cobalt, chromium, lead zinc, and molybdenum. The similarity of the metal assemblage, including uranium of the San Rafael Swell asphaltites, to the metal assemblage in crude oil and other bituminous materials suggests that these metals were concentrated in the asphaltites from petroleum. However, the hypothesis that uranium minerals were already present before the hydrocarbons were introduced and that some sort of replacement or uranium minerals by carbon compounds was effected after the petroleum migrated into the uranium deposit should not be disregarded. The widespread association of uranium with asphaltic material suggests that it also may have been concentrated by some agency connected with the formation of petroleum. The problem of the association of uranium and other trace metals with hydrocarbons should be studied further both in the field and in the laboratory.

Geology and mineral deposits of the Minnie Moore and Bullion mineralized areas, Blaine County, Idaho

USGS Publications Warehouse

Link, Paul Karl; Worl, Ronald G.

2001-01-01

In the early 1880?s the discovery of rich ores in the Minnie Moore and Bullion mineralized areas sparked a rush to settle and develop the Wood River valley. Silver and lead discoveries in these areas spurred the boom in mining after completion of the Oregon Short Line Railroad to Hailey in 1883. In both areas the ore comprises galena, sphalerite, and tetrahedrite in a gangue of siderite, calcite, or quartz. Minor goldbearing quartz veins are also present. The ore is in fissure and replacement veins along fracture systems that formed in Late Cretaceous time, after intrusion of nearby granodiorite or quartz diorite stocks. The ore formed under mesothermal conditions and heat was supplied by the nearby plutons. In the Minnie Moore area, the mineralized veins are cut by low-angle normal faults that are of probable Eocene age. In the Minnie Moore mineralized area, the host rock is the middle part of the Devonian Milligen Formation, (the informal Lucky Coin limestone and Triumph argillite), which is the same stratigraphic level as the host ore in the rich Triumph mine northeast of Hailey. In the Bullion mineralized area, the ore is hosted by the lower member of the Middle Pennsylvanian to Lower Permian Dollarhide Formation. Rich ore was mined in several tunnels that reached the Mayflower vein, a northwest-striking mineralized shear zone. The deposits are thought to be mainly mesothermal veins that formed in association with Cretaceous magmatism. The syngenetic stratiform model of ore formation has often been applied to these deposits, however, no evidence of syngenetic mineralization was found in this study. Faulting has displaced most of the major orebodies and thus has made mining these deposits a challenge.

Features structure of iron-bearing strata’s of the Bakchar deposit, Western Siberia

NASA Astrophysics Data System (ADS)

Asochakova, E. M.

2017-12-01

The ore-bearing strata’s of Bakchar deposit have complicated structural-textural heterogeneity and variable mineral composition. This deposit is one of the most promising areas of localization of sedimentary iron ore. The ore-bearing strata’s are composed mainly of sandstones (sometimes with ferruginous pebbles, less often conglomerates), siltstones and clays. The ironstones are classified according to their lithology and geochemistry into three types: goethite-hydrogoethitic oolitic, glauconite-chloritic and transitional (intermediate) type iron ores. The mineral composition includes many different minerals: terrigenous, authigenic and clayey. Ironstones are characterized by elevated concentrations of many rare and valuable metals present in them as trace elements, additionally alloying (Mn, V, Cr, Ti, Zr, Mo, etc.) and harmful impurities (S, As, Cu, Pb, Zn, P). There are prerequisites for the influence of numerous factors, such as prolonged transgression of the sea, swamping of paleo-river deltas, the appearance of a tectonic fracture zone associated with active bottom tectonics and unloading of catagenetic waters, regression and natural ore enrichment due to the re-washing of slightly-iron rocks. These factors are reflected in the structure of the ore-bearing strata in which rhythmic cycles of ore sedimentation with successive changes in them are distinguished by an association of different mineral composition.

Re-Os sulfide geochronology of the Red Dog sediment-hosted Zn-Pb-Ag deposit, Brooks Range, Alaska

USGS Publications Warehouse

Morelli, R.M.; Creaser, R.A.; Selby, D.; Kelley, K.D.; Leach, D.L.; King, A.R.

2004-01-01

The Red Dog sediment-hosted deposit in the De Long Mountains of northern Alaska is the largest Zn producer in the world. Main stage mineralization is characterized by massive sulfide ore and crosscutting subvertical veins. Although the vein mineralization is clearly younger than the massive ore, the exact temporal relationship between the two is unclear. Re-Os geochronology of pyrite is used to determine the absolute age of main stage ore at Red Dog. A 10-point isochron on both massive and vein pyrite yields an age of 338.3 ?? 5.8 Ma and is interpreted to represent the age of main stage ore. The Re-Os data indicate that both massive and vein ore types are coeval within the resolution of the technique. Formation of the Red Dog deposit was associated with extension along a passive continental margin, and therefore the Re-Os age of main stage ore constrains the timing of rifting as well as the age of the host sedimentary rocks. Sphalerite from both massive and vein ore yields imprecise ages and shows a high degree of scatter compared to pyrite. We suggest that the Re-Os systematics of sphalerite can be disturbed and that this mineral is not reliable for Re-Os geochronology. ?? 2004 by Economic Geology.

Localization of mineralization, its age, and relationship to magmatism at the Mogot silver-base-metal deposit, North Stanovoi metallogenic zone in the southeastern framework of the North Asian Craton

NASA Astrophysics Data System (ADS)

Buchko, I. V.; Buchko, Ir. V.; Sorokin, A. A.; Ponomarchuk, V. A.; Travin, A. V.

2014-03-01

The results of studying the Mogot silver-base-metal deposit located in the Dzhugdzhur-Stanovoi Superterrane are discussed in this paper. The main ore-controlling structural elements of the studied district are near-latitudinal and NE-trending faults, which are accompanied by zones of hydrothermal metasomatic potassic, propylitic, and argillic alterations, breccias with quartz and quartz-carbonate cement replacing metamorphic rocks and granitoids of the Late Stanovoi Complex. The total sulfide content in ore is 2-3%. The high Ag, Pb, and Zn contents in ore allow us to consider the Mogot deposit as silver-base-metal, since except of orebody 4, there are no silver minerals proper. This indicates that silver is incorporated into crystalline lattice of sulfides. The results of 40Ar/39Ar geochronological investigations show that the hydrothermal ore deposition dated at 127-125 Ma was related to emplacement of intrusions pertaining to the Tynda-Bakaran Complex.

Uranium in sediments, mussels (Mytilus sp.) and seawater of the Krka river estuary.

PubMed

Cuculić, Vlado; Cukrov, Neven; Barisić, Delko; Mlakar, Marina

2006-01-01

The response of an aquatic environment to the decrease of phosphate discharges from a technologically improved transhipment terminal, situated at the Croatian Adriatic coast in the port of Sibenik, has been assessed based on uranium activity and concentration in sediment, seawater and mussels Mytilus sp. The highest 238U activities (485+/-16Bqkg(-1) dry weight) were found in the sediment sample collected from the sampling site closest to the terminal. The maximum concentrations in the sediment samples are above the natural ranges and clearly indicate the harbour activities' influence. The 238U/226Ra activity ratios in sediment samples demonstrate the decreasing trend of phosphate ore input. Mussel samples showed levels of 238U activities in the range from 12.1+/-2.9 to 19.4+/-7.2 Bqkg(-1) dry weight, thus being slightly higher than in normally consumed mussels. Only the seawater, taken just above the bottom sediment at the sampling site closest to the terminal, shows a slightly higher uranium concentration (3.1+/-0.2 microgL(-1)) when compared to the samples taken in upper seawater layers (2.1+/-0.2 microgL(-1)) but is in the range of the concentration level of uranium in natural seawater. Since the transhipment terminal in the port of Sibenik was modernised in 1988, discharge of phosphate ore into the seawater was drastically reduced and, consequently, uranium concentration levels in seawater have decreased. However, enhanced uranium activity levels are still found in deeper sediment layer samples and in mussel.

2D Inversion of DCR and Time Domain IP data: an example from ore exploration

NASA Astrophysics Data System (ADS)

Adrian, J.; Tezkan, B.

2015-12-01

Ore deposits often appear as disseminated sulfidic materials. Exploring these deposits with the Direct Current Resistivity (DCR) method alone is challenging because the resistivity signatures caused by disseminated material is often hard to detect. The Time-domain Induced Polarization (TDIP) method, on the other hand, is qualified to detect areas with disseminated sulfidic ores due to large electrode polarization effects which result in large chargeability anomalies. By employing both methods we gain information about both, the resistivity and the chargeability distribution of the subsurface.On the poster we present the current state of the development of a 2D smoothness constraint inversion algorithm for DCR and TDIP data. The implemented forward algorithm uses a Finite Element approach with an unstructured mesh. The model parameters resistivity and chargeability are connected by either a simple conductivity pertubation approach or a complex conductivity approach.As a case study, the 2D inversion results of DCR/TDIP and RMT data obtained during a survey on a sulfidic copper ore deposit in Turkey are presented. The presence of an ore deposit is indicated by areas with low resistivity and significantly high chargeability in the inversion models.This work is part of the BMBF/TUEBITAK funded project ``Two-dimensional joint interpretation of Radiomagnetotellurics (RMT), Direct Current Resistivity (DCR) and Induced Polarization (IP) data: an example from ore exploration''.

Assessing natural attenuation potential at a uranium (U) in situ recovery site (Rosita, TX, USA) using multiple redox-sensitive isotope systems

NASA Astrophysics Data System (ADS)

Basu, A.; Brown, S. T.; Christensen, J. N.; DePaolo, D. J.; Reimus, P. W.; Heikoop, J. M.; Simmons, A. M.; House, B.; Schilling, K.; Johnson, T. M.; Pelizza, M.

2013-12-01

The In Situ Recovery (ISR) U mining operation at Rosita, TX, USA, involved oxidative dissolution of U from roll front U deposits. This process mobilized U along with other characteristic elements (e.g., Se) from the roll fronts in their soluble and toxic oxidized forms (e.g., U(VI), Se(VI)). The dissolved U(VI) in groundwater poses significant ecological risk due to its chemical toxicity and must be restored below the existing regulatory limit to minimize the environmental impact of ISR mining. However, the undisturbed sediments downgradient to the roll front deposits are expected to remain reduced. Naturally occurring Fe-minerals (e.g., FeS, siderite, magnetite) and microorganisms in the sediments downgradient to ISR activity can reduce dissolved U(VI) to less toxic and insoluble U(IV) and promote natural attenuation. The reduction of oxyanions of U or Se induces measurable isotopic fractionation that can be used to monitor the natural attenuation by downgradient sediments. Here, we used multiple redox-sensitive isotope systems (U, Se, and S) to detect reducing conditions and natural attenuation of U(VI) at the ISR site. We collected groundwater samples from 26 wells located in the ore body, upgradient and downgradient to the ore body. The δ238U values measured in groundwater samples from 23 wells range from 0.48‰ to -1.66‰ (×0.12‰). A preliminary investigation of 6 groundwater samples shows a variation of δ82Se values from -1.44‰ to 5.24‰ (×0.15‰). The δ34SO4 measurements in groundwater vary from 11.8‰ to -19.9‰. The reduction of Se(VI) and SO42- fractionates the lighter isotopes (i.e., 32S and 76Se) in the reduced product phase rendering the remaining reactants in the groundwater enriched in heavier isotopes. Therefore, the high δ82Se and δ34SO4 values may suggest reduction of Se(VI) and SO42-, respectively. The highest δ238U values are observed in the wells located in the ore body or upgradient to the ore body whereas the downgradient wells show significantly lower δ238U values. High δ238U values in most of the wells located in the ore-zone may be attributed to the dissolution of the U ore enriched in 238U. The low δ238U values are generally observed in the wells with low U(VI) concentrations. Since U(VI) reduction fractionates 238U to the solid U(IV) phase, the depletion of 238U in the groundwater samples in the downgradient monitoring wells suggest U(VI) reduction by the downgradient sediments. The δ238U values in the groundwater samples conform to a Rayleigh distillation model with an isotopic fractionation factor α = 1.00013 × 0.00010. Future investigations include characterization of the U ore bearing sediments collected from boreholes in the ore body and downgradient of the ore body, measurement of the δ238U and δ82Se values in the ore and in remaining groundwater samples. The U(VI) reducing capacity and concomitant U isotopic fractionation factors for the sediments from downgradient boreholes will be determined from the batch incubation experiments and flow through column experiments.

Tectonic environments of South American porphyry copper magmatism through time revealed by spatiotemporal data mining

NASA Astrophysics Data System (ADS)

Butterworth, N.; Steinberg, D.; Müller, R. D.; Williams, S.; Merdith, A. S.; Hardy, S.

2016-12-01

Porphyry ore deposits are known to be associated with arc magmatism on the overriding plate at subduction zones. While general mechanisms for driving magmatism are well established, specific subduction-related parameters linking episodes of ore deposit formation to specific tectonic environments have only been qualitatively inferred and have not been formally tested. We develop a four-dimensional approach to reconstruct age-dated ore deposits, with the aim of isolating the tectonomagmatic parameters leading to the formation of copper deposits during subduction. We use a plate tectonic model with continuously closing plate boundaries, combined with reconstructions of the spatiotemporal distribution of the ocean floor, including subducted portions of the Nazca/Farallon plates. The models compute convergence rates and directions, as well as the age of the downgoing plate through time. To identify and quantify tectonic parameters that are robust predictors of Andean porphyry copper magmatism and ore deposit formation, we test two alternative supervised machine learning methods; the "random forest" (RF) ensemble and "support vector machines" (SVM). We find that a combination of rapid convergence rates ( 100 km/Myr), subduction obliquity of 15°, a subducting plate age between 25-70 Myr old, and a location far from the subducting trench boundary (>2000 km) represents favorable conditions for porphyry magmatism and related ore deposits to occur. These parameters are linked to the availability of oceanic sediments, the changing small-scale convection around the subduction zone, and the availability of the partial melt in the mantle wedge. When coupled, these parameters could influence the genesis and exhumation of porphyry copper deposits.

Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China

USGS Publications Warehouse

Fan, Delian; Hein, James R.; Ye, Jie

1999-01-01

The Jiaodingshan Mn-Co and Dawashan Mn deposits are located in the approximately 2-m thick Daduhe unit of the Wufengian strata of Late Ordovician (Ashgill) age. Paleogeographic reconstruction places the deposits at the time of their formation in a gulf between Chengdu submarine rise and the Kangdian continent. The Jiaodingshan and Dawashan deposits occur in algal-reef facies, the former in an atoll-like structure and the latter in a pinnacle reef. Ores are mainly composed of rhodochrosite, kutnahorite, hausmannite, braunite, manganosite, and bementite. Dark red, yellowish-pink, brown, green-gray, and black ores are massive, banded, laminated, spheroidal, and cryptalgal (oncolite, stromatolite, algal filaments) boundstones. Blue, green, and red algal fossils show in situ growth positions. Samples of high-grade Jiaodingshan and Dawashan ores assay as much as 66.7% MnO. Jiaodingshan Mn carbonate ores have mean contents of Ba, Co, and Pb somewhat higher than in Dawashan ores. Cobalt is widely distributed and strongly enriched in all rock types as compared to its crustal mean content. Cobalt is correlated with Cu, Ni, and MgO in both deposits and additionally with Ba and Zn in the Dawashan deposit. The δ13C(PDB) values of Mn carbonate ores (-7.8 to -16.3‰) indicate contributions of carbon from both seawater bicarbonate and the bacterial degradation of organic matter, the latter being 33% to 68%, assuming about -24‰ for the δ13C(PDB) of the organic matter. Host limestones derived carbon predominantly from seawater bicarbonate δ1313C(PDB) of +0.2 to -7‰). NW-trending fault zones controlled development of lithofacies, whereas NE-trending fault zones provided pathways for movement of fluids. The source of Co, Ni, and Cu was mainly from weathering of mafic and ultramafic rocks on the Kangdian continent, whereas contemporaneous volcanic eruptions were of secondary importance. The reefs were likely mineralized during early diagenesis under shallow burial. The reefs were highly porous and acted as the locus for metasomatic replacement by Mn that combined with CO2 produced during oxidation of organic matter in the zone of sulfate reduction and seawater bicarbonate. That metasomatic replacement formed the rhodochrosite ores.

Testing ore deposit models using in situ U-Pb geochronology of hydrothermal monazite: Paleoproterozoic gold mineralization in northern Australia

NASA Astrophysics Data System (ADS)

Rasmussen, Birger; Sheppard, Stephen; Fletcher, Ian R.

2006-02-01

The inability to establish absolute ages for gold deposition in the Pine Creek orogen of northern Australia has led to conflicting ore deposit models, ranging from intrusion related, which predict that gold mineralization was synchronous with granite magmatism (ca. 1835 1820 Ma), to orogenic, which place ore deposition nearly 100 m.y. later. Here we present ion microprobe U-Pb geochronology for a mineralized quartz reef from Tom's Gully mine, Mount Bundey, Northern Territory, Australia, and nearby granitic rocks and associated contact aureoles. Isotopic dating of zircon and monazite indicates that intrusion and contact metamorphism occurred ca. 1825 Ma, whereas hydrothermal monazite from the auriferous quartz reef gives a mean 207Pb/206Pb age of 1780 ± 10 Ma, interpreted as the time of gold mineralization. Mineralization therefore postdated intrusion by ˜45 m.y. and preceded a postulated ca. 1740 1730 Ma cratonwide orogenic gold event by ˜50 m.y. Hence, neither the intrusion-related model nor the recently proposed orogenic model is applicable. Combined with a reevaluation of age data from the nearby Goodall gold deposit, our data suggest that mineralization coincides with, and may be related to, an episode of regional low-grade metamorphism, deformation, and fluid circulation (Shoobridge event). Our results demonstrate the importance of high-precision in situ geochronology and detailed petrography for deciphering age relationships in ore deposits, and of testing the veracity of models for ore formation.

Geology, geochemistry, and genesis of the Greens Creek massive sulfide deposit, Admiralty Island, southeastern Alaska

USGS Publications Warehouse

Taylor, Cliff D.; Johnson, Craig A.

2010-01-01

In 1996, a memorandum of understanding was signed by representatives of the U.S. Geological Survey and Kennecott Greens Creek Mining Company to initiate a cooperative applied research project focused on the Greens Creek massive sulfide deposit in southeastern Alaska. The goals of the project were consistent with the mandate of the U.S. Geological Survey Mineral Resources Program to maintain a leading role in national mineral deposits research and with the need of Kennecott Greens Creek Mining Company to further development of the Greens Creek deposit and similar deposits in Alaska and elsewhere. The memorandum enumerated four main research priorities: (1) characterization of protoliths for the wall rocks, and elucidation of their alteration histories, (2) determination of the ore mineralogy and paragenesis, including metal residences and metal zonation within the deposit, (3) determination of the ages of events important to ore formation using both geochronology and paleontology, and (4) development of computer models that would allow the deposit and its host rocks to be examined in detail in three dimensions. The work was carried out by numerous scientists of diverse expertise over a period of several years. The written results, which are contained in this Professional Paper, are presented by 21 authors: 13 from the U.S. Geological Survey, 4 from Kennecott Greens Creek Mining Company, 2 from academia, and 2 from consultants. The Greens Creek deposit (global resource of 24.2 million tons at an average grade of 13.9 percent zinc, 5.1 percent lead, 0.15 troy ounce per ton gold, and 19.2 troy ounces per ton silver at zero cutoff) formed in latest Triassic time during a brief period of rifting of the Alexander terrane. The deposit exhibits a range of syngenetic, diagenetic, and epigenetic features that are typical of volcanogenic (VMS), sedimentary exhalative (SEDEX), and Mississippi Valley-type (MVT) genetic models. In the earliest stages of rifting, formation of precious-metal-rich silica-barite-carbonate white ores began at low temperature in a shallow, subaqueous setting, probably a thin carbonate shelf on the flanks of the Alexander landmass. Epigenetic carbonate replacement textures in the footwall dolostones are overlain by stratiform silica-carbonate-barite-rich ores and indicate that early mineralization formed at and just beneath the paleo sea floor by mixing of a reduced, precious-metal-rich, base-metal-poor hydrothermal fluid with oxygenated seawater. As rifting intensified, the shelf was downfaulted and isolated as a graben. Isolation of the basin and onset of starved-basin shale sedimentation was concurrent with emplacement of mafic-ultramafic intrusives at shallow levels in the rift, resulting in an increasingly higher temperature and progressively more anoxic ore-forming environment. The formation of the main stage of massive sulfide ores began as the supply of bacterially reduced sulfur increased in the accumulating shales. As the main-stage mineralization intensified, shale sedimentation inundated the hydrothermal system, eventually forming a cap. Biogenic sulfate reduction supplied reduced sulfur to the base of the shales where mixing occurred with hot, base-metal-rich hydrothermal fluids. Ore deposition continued by destruction and epigenetic replacement of the early white ores in proximal areas and by inflation and diagenetic replacement of unlithified shale at the interface between the white ores and the base of the shale cap. Ore deposition waned as the shales became lithified and as the supply of bacterially reduced sulfur to the site of ore deposition ceased. The final stages of rifting resulted in the emplacement of mafic-ultramafic intrusive rocks into the Greens Creek system and extrusion of voluminous basaltic flows at the top of the Triassic section. Greenschist facies metamorphism during the Jurassic-Cretaceous accretion of the Alexander terrane to the continental margin resulted in recrystalli

With Strings Attached: Chinas Economic Policy in the South China Sea

DTIC Science & Technology

2016-06-01

of the resources used to fuel its economy: it imports a majority of its timber , platinum, aluminum, iron ore, and copper. Perhaps though, most...gains access to resources such as oil, copper, uranium, cobalt, and timber .18 In Latin America, China receives iron ore, copper, oil and leather.19 In...The argument is that such a regional peace creates a structure that facilitates the transfer of the resources that China needs to continue to fuel

Spatial-temporal and genetic relationships between gold and antimony mineralization at gold-sulfide deposits of the Ob-Zaisan folded zone

NASA Astrophysics Data System (ADS)

Kalinin, Yu. A.; Naumov, E. A.; Borisenko, A. S.; Kovalev, K. R.; Antropova, A. I.

2015-05-01

The Ob-Zaisan folded zone is a fragment of a single structure composed of Paleozoic sedimentary and volcanogenic rocks (mainly black shale), which was formed at the margin of the Siberian continent and features a common set of magmatic complexes and mineral systems. However, there are some differences that determine the specific geological and metallogenic features of the Irtysh-Zaisan and Kolyvan-Tomsk fragments of the Ob-Zaisan folded zone. In the gold deposits of the West Kalba and Kolyvan-Tomsk auriferous belt, the main gold-sulfide mineralization is controlled by zones of shearing and dynamic metamorphism in carbonaceous carbonate-terrigenous rocks. This type of mineralization was formed in tectonic blocks in a compressional setting. Antimony mineralization is characterized by brecciated textures and the vein-like morphology of ore bodies, reflecting extensional tectonics. At some deposits (Zherek, Mirazh, Dalny), Sb mineralization is spatially separated from the main gold-sulfide ores and shows cross-cutting relations to the principal ore-controlling structures. In other gold deposits, stibnite is spatially associated with disseminated gold-sulfide ores and forms mineral assemblages with Ni, Co, Au, Pb, and Fe (Alimbet, Zhanan, Legostaevskoe, Semiluzhenskoe, and Kamenskoe deposits). This study reveals no direct correlation between Au and Sb in gold-sulfide ores of these deposits. SEM analysis indicated the absence of free gold in stibnite veins. However, atomic absorption and electron microprobe analysis indicated the presence of "invisible gold" from a few ppm to several tens of ppm in the stibnite. High gold contents in the gold-sulfide ores overprinted by antimony mineralization (Suzdalskoe, Zhanan, and Legostaevskoe deposits) can be explained by the processes of regeneration and redeposition. The results of microstructural observations, isotope geochronology, studies of mineral assemblages and fluid inclusions in the ores from gold deposits of the Ob-Zaisan folded zone suggest that antimony mineralization was formed at gold-polysulfide stage, which was separated from the early ore pyrite-arsenopyrite stage by a 30 Ma time gap. It can be assumed that the essentially stibnite mineralization was formed at a separate stage and was separated from the gold-polysulfide mineralization by a 7 Ma interval of tectonic activity. Our Ar-Ar data on sericite from ore samples, combined with U-Pb data on zircons from igneous rocks and previous data from the literature show that there were two major stages of ore formation: the Early Permian (282-270 Ma) and the Early Triassic (250-240 Ma). Most researchers suggest that these stages of mineralization can be related to the epochs of intraplate magmatism that led to the formation of the Tarim (280 Ma) and Siberian (250 Ma) large igneous provinces. These global geological events are generally connected with the influence of Tarim and Siberian mantle plumes.

Massive deep-sea sulphide ore deposits discovered on the East Pacific Rise

USGS Publications Warehouse

Francheteau, Jean; Needham, H.D.; Choukroune, P.; Juteau, Tierre; Seguret, M.; Ballard, Richard D.; Fox, P.J.; Normark, William; Carranza, A.; Cordoba, D.; Guerrero, J.; Rangin, C.; Bougault, H.; Cambon, P.; Hekinian, R.

1979-01-01

Massive ore-grade zinc, copper and iron sulphide deposits have been found at the axis of the East Pacific Rise. Although their presence on the deep ocean-floor had been predicted there was no supporting observational evidence. The East Pacific Rise deposits represent a modern analogue of Cyprus-type sulphide ores associated with ophiolitic rocks on land. They contain at least 29% zinc metal and 6% metallic copper. Their discovery will provide a new focus for deep-sea exploration, leading to new assessments of the concentration of metals in the upper layers of the oceanic crust. ?? 1979 Nature Publishing Group.

Development of Triad approach based system for ecological risk assessment for contaminated areas of Kyrgyzstan

NASA Astrophysics Data System (ADS)

Kydralieva, Kamilia; Uzbekov, Beksultan; Khudaibergenova, Bermet; Terekhova, Vera; Jorobekova, Sharipa

2014-05-01

This research is aimed to develop a high-effective system of an ecological risk assessment and risk-based decision making for anthropogenic ecosystems, with particular focus on the soils of the Kyrgyz Republic. The study is focused on the integration of Triad data including chemical, biological and ecotoxicological soil markers to estimate the potential risk from soils of highly anthropized areas impacted by deposition of different pollutants from mining operation. We focus on technogenic areas of Kyrgyzstan, the former uranium-producing province. Triad-based ecological risk assessment for technogenic sites are not currently used in Kyrgyzstan. However, the vitality of such research is self-evident. There are about 50 tailing dumps and more than 80 tips of radioactive waste which are formed as a result of uranium and complex ores (mercury, antimony, lead, cadmium and etc) mining around the unfavorable aforementioned places. According to the Mining Wastes' Tailings and Fills Rehabilitation Centre established in 1999 by a special Government's Resolution, one of the most ecologically dangerous uranium tailings resides in Kadzhi-Say. Although uranium processing is no longer practiced in Kadzhi-Say, a large number of open landfills and uranium ore storages still remain abandoned at the vicinity of this settlement. These neglected sites have enormous problems associated with soil erosion known as "technogenic deserts". The upper soil horizons are deprived of humus and vegetation, which favor the formation of low-buffer landscapes in the zones of maximum contamination. As a result, most of these areas are not re-cultivated and remain in critical environmental condition (Bykovchenko, et al., 2005; Tukhvatshin, 2005; Suranova, 2006). Triad data for assessing environmental risk and biological vulnerability at contaminated sites will be integrated. The following Triad-based parameters will be employed: 1) chemical soil analyses (revealing the presence of potentially dangerous substances), 2) ecological parameters (assessing changes in microorganism's community structure and functions, bioindication); and 3) toxicological bioassays (utilizing classical endpoints such as survival and reproduction rates, genotoxicity). The output will be consisted of 3 indexes: 1) Environmental Risk Index, quantifying the level of biological damage at population-community level, 2) Biological Vulnerability Index, assessing the potential threats to biological equilibria, and 3) Genotoxicity Index, screening genotoxic effects. Multi-criteria Decision Analysis (MCDA) will be used to integrate a set of environmental Triad data to be obtained during the project, which will be carried out in order to estimate the potential risk from soil contamination of the highly anthropized areas of Kadzhi-Say, which have been impacted by deposition of heavy metals. The basis of the development under this research is studies with a particular focus concerning the biocenosis mapping of Kyrgyz soils (Mamytova et al., 2003, 2010), investigations on interaction of humic substances with soil contaminants (Jorobekova, Kydralieva, Khudaibergenova, 2004; Khudaibergenova, 2005, 2007), and in addition, technical approach for ecotoxicological assessment of soils (Terekhova, 2007, 2011). Soil ecotoxicological estimation has been studied with a battery of tests using test-organisms of many trophic levels. Currently, bioindication of soils with various humus states is under study (Senesi, Yakimenko 2007; Yakimenko, et al., 2008).

Nonlinear metallogeny and the depths of the earth

NASA Astrophysics Data System (ADS)

Shcheglov, A. D.; Govorov, I. N.

This book is concerned with the basic relations regarding a new approach in the field of knowledge of metallogenesis, taking into account the complex character of the mutual dependence between ore deposits, the structure of the earth's crust, and depth relations. The principles of nonlinear metallogeny are examined, giving attention to the development of the metallogenic science during the past few years, the formation of the concept 'nonlinear metallogeny', the main aspects of nonlinear metallogeny, the origin of the ore deposits and the characteristics of ore formations in the mantle, the parallel manifestation of ore-forming processes in the crust, sedimentary-hydrothermal ore formations and their place in nonlinear metallogeny, and various types of rock and ore formations. The structure, composition, and metalliferous characteristics found at various depth zones of the tectonosphere are discussed along with the geochemical and metallogenic heterogeneity in the mantle. General questions of nonlinear metallogeny are also investigated.

Sediment-hosted micro-disseminated gold mineralization constrained by basin paleo-topographic highs in the Youjiang basin, South China

NASA Astrophysics Data System (ADS)

Liu, Jianming; Ye, Jie; Ying, Hanlong; Liu, Jiajun; Zheng, Minghua; Gu, Xuexiang

2002-06-01

The Youjiang basin is a Devonian-Triassic rift basin on the southern margin of the Yangtze Craton in South China. Strong syndepositional faulting defined the basin-and-range style paleo-topography that further developed into isolated carbonate platforms surrounded by siliciclastic filled depressions. Finally, thick Triassic siliciclastic deposits covered the platforms completely. In the Youjiang basin, numerous sediment-hosted, micro-disseminated gold (SMG) deposits occur mainly in Permian-Triassic chert and siliciclastic rocks. SMG ores are often auriferous sedimentary rocks with relatively low sulfide contents and moderate to weak alteration. Similar to Carlin-type gold ores in North America, SMG ores in the Youjiang basin are characterized by low-temperature mineral assemblages of pyrite, arsenopyrite, realgar, stibnite, cinnabar, marcasite, chalcedony and carbonate. Most of the SMG deposits are remarkably distributed around the carbonate platforms. Accordingly, there are platform-proximal and platform-distal SMG deposits. Platform-proximal SMG deposits often occur in the facies transition zone between the underlying platform carbonate rocks and the overlying siliciclastic rocks with an unconformity (often a paleo-karst surface) in between. In the ores and hostrocks there are abundant synsedimentary-syndiagenetic fabrics such as lamination, convolute bedding, slump texture, soft-sediment deformation etc. indicating submarine hydrothermal deposition and syndepositional faulting. Numerous fluid-escape and liquefaction fabrics imply strong fluid migration during sediment basin evolution. Such large-scale geological and fabric evidence implies that SMG ores were formed during basin evolution, probably in connection with basinal fluids. It is well known that basinal fluids (especially sediment-sourced fluids) will migrate generally (1) upwards, (2) towards basin margins or basin topographic highs, (3) and from thicker towards thinner deposits during basin evolution. The isolated carbonate platform (as a basin paleo-high) and related syndepositional fault system, together with the unconformity-related facies succession, may have controlled the migration pathway of ore-forming basinal fluids and subsequently determined the location of SMG deposits in the Youjiang basin. Unlike Carlin-type gold deposits, SMG mineralization in the Youjiang basin may represent an integral aspect of the dynamic evolution of extensional basins along divergent continental margins.

Sulfur, carbon, hydrogen, and oxygen isotope geochemistry of the Idaho cobalt belt

USGS Publications Warehouse

Johnson, Craig A.; Bookstrom, Arthur A.; Slack, John F.

2012-01-01

Cobalt-copper ± gold deposits of the Idaho cobalt belt, including the deposits of the Blackbird district, have been analyzed for their sulfur, carbon, hydrogen, and oxygen isotope compositions to improve the understanding of ore formation. Previous genetic hypotheses have ranged widely, linking the ores to the sedimentary or diagenetic history of the host Mesoproterozoic sedimentary rocks, to Mesoproterozoic or Cretaceous magmatism, or to metamorphic shearing. The δ34S values are nearly uniform throughout the Blackbird dis- trict, with a mean value for cobaltite (CoAsS, the main cobalt mineral) of 8.0 ± 0.4‰ (n = 19). The data suggest that (1) sulfur was derived at least partly from sedimentary sources, (2) redox reactions involving sulfur were probably unimportant for ore deposition, and (3) the sulfur was probably transported to sites of ore for- mation as H2S. Hydrogen and oxygen isotope compositions of the ore-forming fluid, which are calculated from analyses of biotite-rich wall rocks and tourmaline, do not uniquely identify the source of the fluid; plausible sources include formation waters, metamorphic waters, and mixtures of magmatic and isotopically heavy meteoric waters. The calculated compositions are a poor match for the modified seawaters that form vol- canogenic massive sulfide (VMS) deposits. Carbon and oxygen isotope compositions of siderite, a mineral that is widespread, although sparse, at Blackbird, suggest formation from mixtures of sedimentary organic carbon and magmatic-metamorphic carbon. The isotopic compositions of calcite in alkaline dike rocks of uncertain age are consistent with a magmatic origin. Several lines of evidence suggest that siderite postdated the emplacement of cobalt and copper, so its significance for the ore-forming event is uncertain. From the stable isotope perspective, the mineral deposits of the Idaho cobalt belt contrast with typical VMS and sedimentary exhalative deposits. They show characteristics of deposit types that form in deeper environments and could be related to metamorphic processes or magmatic processes, although the isotopic evidence for magmatic components is relatively weak.

The Genesis of Precious and Base Metal Mineralization at the Miguel Auza Deposit, Zacatecas, Mexico

NASA Astrophysics Data System (ADS)

Findley, A. A.; Olivo, G. R.; Godin, L.

2009-05-01

The Miguel Auza mine located in Zacatecas State, Mexico, is a vein-type polymetallic epithermal deposit hosted in deformed argillite, siltstone and, greywacke of the Cretaceous Caracol Formation. Silver-rich base metal veins (0.2 m to >1.5 m wide) are spatially associated with the NE-striking, steeply SE- dipping (70-80°) Miguel Auza fault over a strike length of 1.6 km and a depth of 460 m. A 2 km2 monzonitic stock located in the proximity of the mineralized zones, has previously been interpreted as the source of the mineralizing fluids. Four distinct structural stages are correlated with hydrothermal mineral deposition: (I) The Pre-ore stage is characterized by normal faulting, fracturing of host rock, and rotation of bedding planes. This stage consists of quartz, illite, chlorite, +/- pyrite alteration of sedimentary wall rocks. (II) The Pyrite-vein stage is associated with reverse-sense reactivation of early normal faults, dilation of bedding planes/fractures, and deposition of generally barren calcite + pyrite veinlets. (III) The Main-ore stage is related to the development of reverse-fault- hosted massive sulphide veins. During this stage three phases of mineral deposition are recorded: early pyrite and arsenopyrite, intermediate chalcopyrite, pyrite, arsenopyrite, and base metals, and late base metals and Ag-bearing minerals. Associated gangue minerals during the main ore stage are quartz, muscovite, calcite and chlorite. (IV) The Post-ore stage involves late NW-SE striking block faulting, brecciation and calcite veining. Later supergene oxidation of veins led to deposition of Fe-oxides and hydroxides, commonly filling fractures or replacing early-formed sulphide assemblages. The various vein types display classic epithermal textures including open space filling, banding, comb quartz and brecciation. The Ag-bearing minerals comprise pyrargyrite [Ag3(Sb,As)S3], argentotennantite [(Cu,Ag)10(Zn,Fe)2(Sn,As)4S13], polybasite-pearceite [(Ag,Cu)16(Sb,As)2S11], and acanthite [AgS2]; associated sulphides include galena, sphalerite, chalcopyrite, arsenopyrite and pyrite. In the main ore zone, base metal sulphides are commonly intergrown with the Ag-bearing sulfosalts. Analyses of galena show no significant silver values indicating that silver grades are exclusively associated with the Ag-bearing sulfosalts and sulphides. The distribution of the Sb/(Sb + As) ratios in the silver sulfosalts indicate that the ore forming fluid(s) was consistently antimony-rich during the Ag-rich ore deposition with no significant variation laterally, vertically, or along strike of the vein systems. However, Ag/(Ag + Cu) values in argentotennantite decrease along-strike from NE to SW and with depth. Compositions of argentotennantite + pyrargyrite + sphalerite indicate a primary depositional temperature around 325-350° C for the late phase of the Main-ore stage. Compositions of sphalerite also show an increasing trend in FeS (mol %) along strike of the deposit from NE to SW. The geometric relationship between the various structures, vein types, and the regional Miguel Auza fault zone suggest episodic reverse-sense reactivation of normal faults. It is argued that the structural evolution of the area, and, in particular, the Main-ore stage, provided transport pathways for metal-rich fluids and controlled the orientations of ore-bearing veins. Variations in mineral chemistry suggest that the rocks in the NE sector interacted with hotter fluids than in the SW part of the deposit.

UTEX LEACHING, THICKENING AND FILTRATION TESTS. Topical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stanley, A.; George, D.R.; Thomas, P.N.

1954-03-15

A series of leaching, thickening, and filtration tests was undertaken to determine minimum conditions for high uranium extractions and obtain thickening and filtration data. The ore represented by the sample responded to cold and hot leaching with the minimum condition for uranium extraction being 500 pounds of H/ sub 2/SO/sub 4/ per ton and five pounds NaClO/sub 3/ per ton leached at room temperature for l6 hours with uranium extraction of over 95%. Thickening and filtration were economical if a reagent such as S-3000 or Guar gum was used. (auth)

Remote sensing and uranium exploration at Lisbon Valley, Utah

NASA Technical Reports Server (NTRS)

Conel, J. E.; Niesen, P. L.

1981-01-01

As part of the joint NASA-Geosat uranium test case program, aircraft-acquired multispectral scanner data are used to investigate the distribution of bleaching in Windgate sandstone exposed in Lisbon Valley anticline, Utah. It is noted that all of the large ore bodies contained in lower Chinle Triassic age or Cutler Permian age strata in this area lie beneath or closely adjacent to such bleached outcrops. The geographic coincidences reported here are seen as inviting renewed interest in speculation of a causal relation between occurrences of Mississippian-Pennsylvanian oil and gas in this area and of Triassic uranium accumulation and rock bleaching.

Production Quality, Value and Revenue in Polish Copper Mines

NASA Astrophysics Data System (ADS)

Malewski, Jerzy

2016-10-01

Polish copper ore deposits, located in the Legnica-Głogów Copper District (LGOM) documented an area of over 200 km2, at a depth of 600-1400 meters. The estimated resources equal to 22.7 million tonnes of copper (proven and probable), or 44.4 million t (measured and indicated), or 8.7 million t (infered), at the criterion of profitability at a cost less than 50 cents per ton of ore. Organization of production takes place in the combine of mining and metallurgy (KGHM). Ore is extracted in three mines: Lubin, Polkowice-Sieroszowice and Rudna. The total production of these mines is about 31 million tonnes/year of ore, from which it receives a 576000 t/y of copper, 1152 t/y of silver, 1066 kg/y of gold, and certain amounts of Pb, Zn, Se, Re, Ni, SO4, H2SO4. The quality (grading) of the ore in exploited deposits is varied, affecting the quality and quantity of produced concentrates, what influence on its market value. The paper presents a brief description of ore deposit and estimates mines revenues and production profit. Calculations show that at today's (June 2016) metal prices each of the mine can expect the following net smelter revenue: Lubin ∼⃒41, P-S ∼⃒70, Rudna ∼⃒75 /t of ore. But estimated cost production differs less, i.e.: 45, 56 and 65/t of ore respectively, because of mining depth.

Thallium-rich pyrite ores from the Apuan Alps, Tuscany, Italy:constraints for their origin and environmental concerns

NASA Astrophysics Data System (ADS)

D'Orazio, Massimo; Biagioni, Cristian; Dini, Andrea; Vezzoni, Simone

2017-06-01

The southern sector of the Apuan Alps (AA) massif, Tuscany, Italy, is characterized by the occurrence of a series of baryte-pyrite-iron oxide orebodies whose Tl-rich nature was recognized only recently. The geochemistry of the pyrite ore was investigated through inductively coupled plasma mass spectrometry. In addition, lead isotope data for selected pyrite ores from AA were collected. Pyrite ores are characterized by a complex geochemistry, with high concentrations of Tl (up to 1100 μg/g) coupled with high As and Sb contents; the Co/Ni ratio is always <1. Geochemical data of pyrite and marcasite ore samples from other mining districts of Tuscany have been collected in order to compare them with those from the AA. These samples usually have very low Tl content (less than 2 μg/g) and high to very high Co/Ni and As/Sb ratios. Only some samples from the Sb-Hg ore deposits showed very high Tl concentrations (up to 3900 μg/g). Another difference is related to the lead isotope composition, with pyrite ores from AA markedly less radiogenic than those from the other deposits from Tuscany. Geochemical data of pyrite ores from AA give new insights on the genesis of the baryte-pyrite-iron oxide orebodies, relating their formation to low-temperature hydrothermal systems active during early Paleozoic; in addition, these data play a fundamental role in assessing the environmental impact of these deposits.

Carbon Characteristics and Biogeochemical Processes of Uranium Accumulating Organic Matter Rich Sediments in the Upper Colorado River Basin

NASA Astrophysics Data System (ADS)

Boye, K.; Noel, V.; Tfaily, M. M.; Dam, W. L.; Bargar, J.; Fendorf, S. E.

2015-12-01

Uranium plume persistence in groundwater aquifers is a problem on several former ore processing sites on floodplains in the upper Colorado River Basin. Earlier observations by our group and others at the Old Rifle Site, CO, have noted that U concentrations are highest in organic rich, fine-grained, and, therefore, diffusion limited sediment material. Due to the constantly evolving depositional environments of floodplains, surficial organic matter may become buried at various stages of decomposition, through sudden events such as overbank flooding and through the slower progression of river meandering. This creates a discontinuous subsurface distribution of organic-rich sediments, which are hotspots for microbial activity and thereby central to the subsurface cycling of contaminants (e.g. U) and biologically relevant elements (e.g. C, N, P, Fe). However, the organic matter itself is poorly characterized. Consequently, little is known about its relevance in driving biogeochemical processes that control U fate and transport in the subsurface. In an investigation of soil/sediment cores from five former uranium ore processing sites on floodplains distributed across the Upper Colorado River Basin we confirmed consistent co-enrichment of U with organic-rich layers in all profiles. However, using C K-edge X-ray Absorption Spectroscopy (XAS) coupled with Fourier-Transformed Ion-Cyclotron-Resonance Mass-Spectroscopy (FT-ICR-MS) on bulk sediments and density-separated organic matter fractions, we did not detect any chemical difference in the organic rich sediments compared to the surrounding coarser-grained aquifer material within the same profile, even though there were differences in organic matter composition between the 5 sites. This suggests that U retention and reduction to U(IV) is independent of C chemical composition on the bulk scale. Instead it appears to be the abundance of organic matter in combination with a limited O2 supply in the fine-grained material that stimulate anaerobic microbial processes responsible for U enrichment. Thus, the chemical composition of organic matter is subordinate to the physical environment and total organic matter content in controlling U reduction and retention processes.

Guinea’s 2008 Military Coup and Relations with the United States

DTIC Science & Technology

2009-07-16

Guinea’s extractive industry sector is of financial and strategic interest to the United States. In addition to gold, diamonds, uranium , and potential...agency’s legal mandate and authorities have not been clearly defined, and the CNDD has not publicly outlined how the agency is meant to interact with...Guinea’s economy relies heavily on primary commodity exports, notably bauxite (used to produce aluminum), gold, diamonds, uranium , and iron ore

High-grade iron ore at Windarling, Yilgarn Craton: a product of syn-orogenic deformation, hypogene hydrothermal alteration and supergene modification in an Archean BIF-basalt lithostratigraphy

NASA Astrophysics Data System (ADS)

Angerer, Thomas; Hagemann, Steffen G.; Danyushevsky, Leonid

2013-08-01

Banded iron formation (BIF)-hosted iron ore deposits in the Windarling Range are located in the lower greenstone succession of the Marda-Diemals greenstone belt, Southern Cross domain, Yilgarn Craton and constitute a total hematite-martite-goethite ore resource of minimum 52 Mt at 60 wt.% Fe (0.07 P). Banded iron formation is interlayered with high-Mg basalts at Windarling and precipitated during episodes of volcanic quiescence. Trace element content and the rare earth element (REE) ratios Y/Ho (42 to 45), Sm/Yb (1.5), together with positive La and Gd anomalies in `least-altered' hematite-magnetite-metachert-BIF indicate the precipitation from Archean seawater that was fertilised by hydrothermal vent fluids with a basaltic HREE-Y signature. Hypogene iron ore in sub-greenschist facies metamorphosed BIF formed during three distinct stages: ore stage 1 was a syn- to post-metamorphic, syn-D1, Fe-Ca-Mg-Ni-Co-P-REE metasomatism that produced local Ni-REE-rich Fe-dolomite-magnetite alteration in BIF. Hydrothermal alteration was induced by hot fluid flow controlled by brittle-ductile reactivation of BIF-basalt margins and crosscutting D1 faults. The Ni-Co-rich content of dolomite and a shift in REE ratios in carbonate-altered BIF towards Archean mafic rock signature (Y/Ho to 31 to 40, Sm/Yb to 1 to 2 and Gd/Gd* to 1.2 to 1.4) suggest that high-Mg basalts in the Windarling Range were the primary source of introduced metals. During ore stage 2, a syn-deformational and likely acidic and oxidised fluid flow along BIF-basalt margins and within D1 faults leached carbonate and precipitated lepidoblastic and anhedral/granoblastic hematite. High-grade magnetite-hematite ore is formed during this stage. Ore stage 3 hydrothermal specular hematite (spcH)-Fe-dolomite-quartz alteration was controlled by a late-orogenic, brittle, compressional/transpressional stage (D4; the regional-scale shear-zone-related D3 is not preserved in Windarling). This minor event remobilised iron oxides, carbonate and quartz to form veins and breccia but did not generate significant volumes of iron ore. Ore stage 4 involved Mesozoic(?) to recent supergene oxidation and hydration in a weathering environment reaching down to depths of ˜100 to maximum 200 m below surface. Supergene ore formation involved goethite replacement of dolomite and quartz as well as martitisation. Important `ground preparation' for supergene modification and upgrade were mainly the formation of steep D1 to D4 structures, steep BIF/basalt margins and particularly the syn-D1 to syn-D2 carbonate alteration of BIF that is most susceptible to supergene dissolution. The Windarling deposits are structurally controlled, supergene-modified hydrothermal iron ore systems that share comparable physical, chemical and ore-forming characteristics to other iron ore deposits in the Yilgarn Craton (e.g. Koolyanobbing, Beebyn in the Weld Range, Mt. Gibson). However, the remarkable variety in pre-, syn- and post-deformational ore textures (relative to D1 and D2) has not been described elsewhere in the Yilgarn and are similar to the ore deposits in high-strain zones, such as of Brazil (Quadrilátero Ferrífero or Iron Quadrangle) and Nigeria. The overall similarity of alteration stages, i.e. the sequence of hydrothermal carbonate introduction and hypogene leaching, with other greenstone belt-hosted iron ore deposits supports the interpretation that syn-orogenic BIF alteration and upgrade was crucial in the formation of hypogene-supergene iron ore deposits in the Yilgarn Craton and possibly in other Archean/Paleoproterozoic greenstone belt settings worldwide.

Gold in the Black Hills, South Dakota, and how new deposits might be found

USGS Publications Warehouse

Norton, James Jennings

1974-01-01

Of the recorded production of 34,694,552 troy ounces of gold mined in South Dakota through 1971, about 90 percent has come from Precambrian ore bodies in the Homestake mine at Lead in the northern Black Hills. Most of the rest has come from ore deposited in the Deadwood Formation (Cambrian) by hydrothermal replacement during early Tertiary igneous activity. About 99 percent of the total production has been within a radius of 5 miles (8 km) of Lead. Elsewhere, prospecting has been intense, both in the Precambrian rocks, which are exposed over an area 61 by 26 miles (98 by 42 km), and in nearby Paleozoic rocks. All the known ore bodies have been found either at the surface or in subsurface workings of operating mines. Efforts to find totally new deposits have been modest and sporadic; no comprehensive and systematic program has ever been attempted. Obviously, any exploration program should be aimed at finding a new deposit resembling the Homestake in the Precambrian, but discovery in the Deadwood of a new group of ore bodies containing several hundred thousand ounces of gold would certainly be worthwhile. Evidence has long been available that the Deadwood deposits and the Homestake deposit are somehow related. Current opinion is that (1) the Homestake ore is mainly Precambrian, (2) a trivial amount of Homestake ore is Tertiary, (3)gold in Deadwood basal conglomerate is largely of placer origin, and (4) the gold of replacement deposits in the Deadwood and in other rock units came originally from sources similar to the Homestake deposit or its parent materials. Homestake ore is virtually entirely contained in a unit of iron-formation locally known as the Homestake Formation, which seemingly had more gold in the original sediments than similar rocks exposed elsewhere in the Black Hills. Gold, sulfur, and other constituents were subsequently concentrated in ore shoots in zones of dilation caused by cross folds that deformed earlier major folds. These ore shoots are in metamorphic rocks of a grade just above the garnet isograd, in a zone where the principal iron-magnesium mineral of the iron-formation changes from a carbonate (sideroplesite) to a silicate (cummingtonite). This metamorphic reaction would release carbon dioxide to the fluid that presumably formed the ore bodies. In short, three controls over localization of the ore have been identified: (1) the cross folds; (2) the so-called Homestake Formation, which passes beneath Paleozoic rocks north of Lead and has not been proved to reappear anywhere else in the Black Hills (Other units of iron-formation less enriched in gold might locally become more like the Homestake Formation beneath the cover of Paleozoic rocks.}; (3} proximity to the garnet isograd--nearly all the exposed Precambrian rocks in the Black Hills are at a metamorphic grade higher than this isograd--and occurrence of this isograd zone mostly beneath Paleozoic rocks. In searching for new deposits, one can guess from existing data where Precambrian rocks of suitable nature may be concealed. The usefulness of such guesses can be increased if they are made with information about the distribution of gold in younger rocks. Gold in the Deadwood basal conglomerate would be the simplest indicator of a deposit once exposed on the pre-Deadwood surface. Tertiary replacement deposits in the Deadwood or other rocks, which obtained their gold from Precambrian sources that may be nearby or far away, can also be helpful; they, like anomalies found by geochemical sampling, at least outline the regions of mineralizing activity. A suitable approach to exploration is to make a thorough study of the stratigraphy, the structure, and the metals geochemistry of the Deadwood Formation and associated rocks, chiefly in the northern Black Hills but to a lesser extent elsewhere in localities where the Precambrian geology seems promising and where gold has been found nearby. Such a program, even if it does not yield

Gases and trace elements in soils at the North Silver Bell deposit, Pima County, Arizona

USGS Publications Warehouse

Hinkle, M.E.; Dilbert, C.A.

1984-01-01

Soil samples were collected over the North Silver Bell porphyry copper deposit near Tucson, Arizona. Volatile elements and compounds in gases derived from the soils and metallic elements in the soils were analyzed in order: (1) to see which volatile constituents of the soils might be indicative of the ore body or the alteration zones; and (2) to distinguish the ore and alteration zones by comparison of trace elements in the soil. Plots of analytical data on trace elements in soils indicated a typical distribution pattern for metals around a porphyry copper deposit, with copper, molybdenum, and arsenic concentrations higher over the ore body, and zinc, lead, and silver concentrations higher over the alteration zones. Higher than average concentrations of helium, carbon disulfide, and sulfur dioxide adsorbed on soils were found over the ore body, whereas higher concentrations of carbon dioxide and carbonyl sulfide were found over the alteration zones. ?? 1984.

How metalliferous brines line Mexican epithermal veins with silver

PubMed Central

Wilkinson, Jamie J.; Simmons, Stuart F.; Stoffell, Barry

2013-01-01

We determined the composition of ~30-m.y.-old solutions extracted from fluid inclusions in one of the world's largest and richest silver ore deposits at Fresnillo, Mexico. Silver concentrations average 14 ppm and have a maximum of 27 ppm. The highest silver, lead and zinc concentrations correlate with salinity, consistent with transport by chloro-complexes and confirming the importance of brines in ore formation. The temporal distribution of these fluids within the veins suggests mineralization occurred episodically when they were injected into a fracture system dominated by low salinity, metal-poor fluids. Mass balance shows that a modest volume of brine, most likely of magmatic origin, is sufficient to supply the metal found in large Mexican silver deposits. The results suggest that ancient epithermal ore-forming events may involve fluid packets not captured in modern geothermal sampling and that giant ore deposits can form rapidly from small volumes of metal-rich fluid. PMID:23792776

Differentiation of commercial vermiculite based on statistical analysis of bulk chemical data: Fingerprinting vermiculite from Libby, Montana U.S.A

USGS Publications Warehouse

Gunter, M.E.; Singleton, E.; Bandli, B.R.; Lowers, H.A.; Meeker, G.P.

2005-01-01

Major-, minor-, and trace-element compositions, as determined by X-ray fluorescence (XRF) analysis, were obtained on 34 samples of vermiculite to ascertain whether chemical differences exist to the extent of determining the source of commercial products. The sample set included ores from four deposits, seven commercially available garden products, and insulation from four attics. The trace-element distributions of Ba, Cr, and V can be used to distinguish the Libby vermiculite samples from the garden products. In general, the overall composition of the Libby and South Carolina deposits appeared similar, but differed from the South Africa and China deposits based on simple statistical methods. Cluster analysis provided a good distinction of the four ore types, grouped the four attic samples with the Libby ore, and, with less certainty, grouped the garden samples with the South Africa ore.

Hydrogeology of an ancient arid closed basin: implications for tabular sandstone-hosted uranium deposits

USGS Publications Warehouse

Sanford, R.F.

1990-01-01

Hydrogeologic modeling shows that tabular-type uranium deposits in the Grants uranium region of the San Juan basin, New Mexico, formed in zones of ascending and discharging regional ground-water flow. The association of either lacustrine mudstone or actively subsiding structures and uranium deposits can best be explained by the occurrence of lakes at topographic depressions where ground water having different sources and compositions is likely to converge, mix, and discharge. Ascending and discharging flow also explains the association of uranium deposits with underlying evaporites and suggests a brine interface. The simulations contradict previous suggestions that ground water moved downward in the mudflat. -Author

First find of platinum group metals in the ore of Kirganik copper-porphyry deposit (Kamchatka)

NASA Astrophysics Data System (ADS)

Sidorov, E. G.; Ignatyev, E. K.; Chubarov, V. M.

2017-08-01

The Kirganik copper-porphyry deposit is situated in the central part of the Sredinnyi Mountain Range of Kamchatka and is confined to fields of development of potassic orthoclase metasomatite and hypabyssal intrusions of shonkinite. Platinum group metals (PGMs), such as merenskyite, kotulskite, keithconnite, and temagamite, were discovered in the chalcopyrite-bornite and chalcopyrite-bornite-chalcosine ore of the deposit for the first time.

Descriptive models of major uranium deposits in China - Some results of the Workshop on Uranium Resource Assessment sponsored by the International Atomic Energy Agency, Vienna, Austria, in cooperation with China National Nuclear Corporation, Beijing, and the U.S. Geological Survey, Denver, Colorado, and Reston, Virginia

USGS Publications Warehouse

Finch, W.I.; Feng, S.; Zuyi, C.; McCammon, R.B.

1993-01-01

Four major types of uranium deposits occur in China: granite, volcanic, sandstone, and carbonaceous-siliceous-pelitic rock. These types are major sources of uranium in many parts of the world and account for about 95 percent of Chinese production. Descriptive models for each of these types record the diagnostic regional and local geologic features of the deposits that are important to genetic studies, exploration, and resource assessment. A fifth type of uranium deposit, metasomatite, is also modeled because of its high potential for production. These five types of uranium deposits occur irregularly in five tectonic provinces distributed from the northwest through central to southern China. ?? 1993 Oxford University Press.

The influence of geomorphology on the role of women at artisanal and small-scale mine sites

USGS Publications Warehouse

Malpeli, Katherine C.; Chirico, Peter G.

2013-01-01

The geologic and geomorphic expressions of a mineral deposit determine its location, size, and accessibility, characteristics which in turn greatly influence the success of artisans mining the deposit. Despite this critical information, which can be garnered through studying the surficial physical expression of a deposit, the geologic and geomorphic sciences have been largely overlooked in artisanal mining-related research. This study demonstrates that a correlation exists between the roles of female miners at artisanal diamond and gold mining sites in western and central Africa and the physical expression of the deposits. Typically, women perform ore processing and ancillary roles at mine sites. On occasion, however, women participate in the extraction process itself. Women were found to participate in the extraction of ore only when a deposit had a thin overburden layer, thus rendering the mineralized ore more accessible. When deposits required a significant degree of manual labour to access the ore due to thick overburden layers, women were typically relegated to other roles. The identification of this link encourages the establishment of an alternative research avenue in which the physical and social sciences merge to better inform policymakers, so that the most appropriate artisanal mining assistance programs can be developed and implemented.

Micro-PIXE characterisation of uranium occurrence in the coal zones and the mudstones of the Springbok Flats Basin, South Africa

NASA Astrophysics Data System (ADS)

Nxumalo, V.; Kramers, J.; Mongwaketsi, N.; Przybyłowicz, W. J.

2017-08-01

Uranium occurrence and characterisation in the coal samples of the upper coal zones of the Vryheid Formation and mudstones of the Volksrust Formation was investigated using micro-PIXE (Proton-Induced X-ray Emission) and proton backscattering spectrometry (BS) in conjunction with the nuclear microprobe. Two styles of uranium mineralisation in the Springbok Flats Basin were found: syngenetic mineralisation in which uranium occurs organically bound with coal matrix, with no discrete uranium minerals formed, and epigenetic mineralisation in which uranium occurs in veins that are filled with coffinite with botryoidal texture in the mudstones of the Volksrust Formation, overlying the coal zones. Micro-PIXE analysis made it possible to map out trace elements (including uranium) associated with the coals at low levels of detection, which other techniques such as SEM-EDS and ore microscopy failed. This information will help in better understanding of the best extraction methods to be employed to recover uranium from the coals of the Springbok Flats Basin.

In situ strontium and sulfur isotope investigation of the Ni-Cu-(PGE) sulfide ore-bearing Kevitsa intrusion, northern Finland

NASA Astrophysics Data System (ADS)

Luolavirta, Kirsi; Hanski, Eero; Maier, Wolfgang; Lahaye, Yann; O'Brien, Hugh; Santaguida, Frank

2018-01-01

The 2.06-Ga Kevitsa mafic-ultramafic intrusion in northern Finland hosts a large disseminated Ni-Cu-PGE deposit. The deposit occurs in the ultramafic olivine-pyroxene cumulates and shows a range in Ni tenors varying from 4-7 wt% (regular ore) to > 10 wt% (Ni-PGE ore). There are also a metal-poor sulfide mineralization (false ore) and contact mineralization that are uneconomic (Ni tenor < 4 wt%). The obtained 87Sr/86Sr(i) values of the Kevitsa ultramafic cumulates are highly radiogenic (> 0.7045) in comparison to the estimated depleted mantle Sr isotope ratio of 0.702 at 2.06 Ga. The sulfur δ 34S values are generally higher than + 2‰, which together with the Sr isotope data imply involvement of crustal material in the genesis of the Kevitsa intrusion and its ores. The 87Sr/86Sr(i) values obtained from the ore-bearing domain of the intrusion show stratigraphic variation and exceed 0.7050, with the maximum value reaching up to 0.7109. In contrast, in rocks around the ore domain, the initial Sr isotope compositions remain more or less constant (0.7047-0.7060) throughout the intrusive stratigraphy. The isotope data suggest that the ore-bearing domain of the intrusion represents a dynamic site with multiple injections of variably contaminated magma, whereas the surrounding part of the intrusion experienced a less vigorous emplacement history. No correlation is observed between the strontium and sulfur isotope compositions. This is explained by bulk assimilation of the silicate magma in a deeper staging magma chamber and variable assimilation of sulfur during magma transport into the Kevitsa magma chamber. The low level of metals in false ore and the Ni-depleted nature of its olivine suggest that some sulfides may have precipitated and deposited in the feeder conduit during the initial stage of magma emplacement. Cannibalization of early-formed sulfides by later magma injections may have been important in the formation of the economic ore deposit.

Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

NASA Astrophysics Data System (ADS)

Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

2015-04-01

India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled with kaolinite and gibbsite, which make it low grade. Massive iron ores are devoid of any lamination and usually associated with BHJ and lower shale. The thickness of the massive ore layer varies with the location. The massive iron ore grades in to well-developed bedded BHJ in depth. Blue dust occurs in association with BHJ as pockets and layers. Although blue dust and friable ore are both powdery ores, and subjected to variable degree of deformation, leading to the formation of folding, faulting and joints of complex nature produce favourable channels. Percolating water play an important role in the formation of blue dust and the subterranean solution offers the necessary acidic environment for leaching of quartz from the BHJ. The dissolution of silica and other alkalis are responsible for the formation of blue dust. The friable and powdery ore on the other hand are formed by soft laminated ore. As it is formed from the soft laminated ore, its alumina content remains high similar to soft laminated ore compaired to blue dust. Mineralogy study suggests that magnetite was the principal iron oxide mineral, now a relict phase whose depositional history is preserved in BHJ, where it remains in the form of martite. The platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Hard laminated ores, martite-goethite ore and soft laminated ore are resultant of desilicification process through the action of hydrothermal fluids. Geochemistry of banded iron-formations of the Noamundi-Koira iron ore deposits shows that they are detritus-free chemical precipitates. The mineralogical and geochemical data suggest that the hard laminated, massive, soft laminated ores and blue dust had a genetic lineage from BIF's aided with certain input from hydrothermal activity. The comparative study of major elemental composition of the basin samples and while plotting a binary diagram, it shows a relation between major oxides against iron oxides, in which iron oxides is taken as a reference oxide (Mirza, 2011). On the other hand, by plotting a binary diagram between chemical index of alteration (CIA) and other oxides while taking the samples of lower, middle and upper shales. It reflects an immobility and mobility of ions during partial and complete weathering processes (Mirza, 2011). Geochemical data indicate that BIF are in general detritus free chemical precipitates. Fe2O3 content of BHJ are varies in between 36.6% to 65.04%. In hard laminated ore, Fe2O3 content varies from 93.8% to 96.38%, Soft laminated ore varies from 83.64% to 89.5% and laterite ore varies from 53.5% to 79.11%. Fe2O3 content in Martite- Goethite ore varies from 86.38% to 89.42% and blue dust having 90.74% to 95.86% and all other oxides like SiO2, Al2O3, CaO, MgO, K2O, Na2O are decreases. Major part of the iron could have been added to the bottom sea water by hydrothermal solutions derived from hydrothermally active anoxic marine environments. The presence of intacalated tuffaceous shales pointing towards the genesis of iron, which could have leached from sea floor by volcanogenic process. Iron and silica of BIF were provided by the hydrothermal solutions emplaced at the vent sites situated at the Archean-Mid Oceanic Ridges. References: Mirza A (2011). Major element geochemistry of iron ore deposits in Noamundi-Koira basin of Singhbhum-Orissa craton (India). MSc thesis, Aligarh Muslim University, India. Saha AK (1994). Crustal evolution of Singhbhum, North Orissa, Eastern India; Geol. Soc. India Memoir 27 341. Sharma M, Basu AR and Ray SL (1994). Sm-Nd isotopic and geochemical study of the Archaean tonalite-amphibolite association from the eastern Indian craton. Contrib. Mineral Petrol. 117:45-55. Van Schalkwyk J and Beukes N J (1986). The Sishen iron ore deposit, Griqualand West; In: Mineral deposits of Southern Africa (eds) Annhaeusser C R and Maske S S, Geological Society of South Africa, Johannesburg, 931-956.

ION EXCHANGE TESTS ON LIQUOR AND PULPS PRODUCED FROM UTEX ORES. Topical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollis, E.T.; Pickwick, F.J. Jr.; Kazanjian, A.R.

1954-07-30

Uranium leach liquors produced from Utex ore by cold leaching, hot leaching, and pugging proved amenable to the lon exchange process, Higher resin loadings were obtained rom the cold leach liquors than from the hot leach and pug liquors. In general, the less vigorous leaching conditions produced liquors which gave the highest resin loadings. In addition, a resin-in-pulp system was operated using the lucite Winchester cells on Utex pulp produced by cold leaching. Satisfactory loadings were obtained. (auth)

Economic Outlook for Radiometric Selection of Ores; POSSIBILITES OUVERTES EN MATIERE ECONOMIQUE PAR SELECTION RADIOMETRIQUE DES MINERAIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Formery, P.; Ziegler, V.

1959-10-31

The radiometric grading of uranium ores is analyzed. The cut-off is defined, and its parameters are derived. Cut-off above ground and underground are statistically interpreted. An evaluation is made of the combined effects of both kinds of cut-off made in succession. The corrections to be made to the radiometric apparatus used are determined. Application of the theory of cutoff to the evaluation of reserves is discussed. (J.S.R.)

Enhanced Uranium Ore Concentrate Analysis by Handheld Raman Sensor: FY15 Status Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bryan, Samuel A.; Johnson, Timothy J.; Orton, Christopher R.

2015-11-11

High-purity uranium ore concentrates (UOC) represent a potential proliferation concern. A cost-effective, “point and shoot” in-field analysis capability to identify ore types, phases of materials present, and impurities, as well as estimate the overall purity would be prudent. Handheld, Raman-based sensor systems are capable of identifying chemical properties of liquid and solid materials. While handheld Raman systems have been extensively applied to many other applications, they have not been broadly studied for application to UOC, nor have they been optimized for this class of chemical compounds. PNNL was tasked in Fiscal Year 2015 by the Office of International Safeguards (NA-241)more » to explore the use of Raman for UOC analysis and characterization. This report summarizes the activities in FY15 related to this project. The following tasks were included: creation of an expanded library of Raman spectra of a UOC sample set, creation of optimal chemometric analysis methods to classify UOC samples by their type and level of impurities, and exploration of the various Raman wavelengths to identify the ideal instrument settings for UOC sample interrogation.« less

Simulation of geochemical processes responsible for the formation of the Zhezqazghan deposit

NASA Astrophysics Data System (ADS)

Ryzhenko, B. N.; Cherkasova, E. V.

2014-05-01

Physicochemical computer simulation of water-rock systems at a temperature of 25-150°C and under a pressure of up to 600 bar has been carried out for quantitative description of the mineralization formation conditions at sandstone- and shale-hosted copper deposits. The simulation is based on geological and geochemical information concerning the Zhezqazghan deposit and considers (i) a source of ore matter, (ii) composition of the fluid that transfers ore matter to the ore formation zone, and (iii) factors of ore concentration. It has been shown that extraction of copper from minerals of rocks and its accumulation in aqueous solution are optimal at a high mass ratio of rock to water (R/W > 10), Eh of +200 to -100 mV, and an obligatory content of chloride ions in the aqueous phase. The averaged ore-bearing fluid Cl95SO44//Ca50(Na + K)30Mg19 (eq %), pH ˜ 4, mineralization of up to 400 g/L, is formed by the interaction of red sandstone beds with a sedimentogenic brine (a product of metamorphism of seawater in carbonate rocks enriched in organic matter). The ore concentration proceeds in the course of cooling from 150 to 50°C during filtration of ore-bearing fluid through red sandstone beds in the rock-water system thermodynamically opened with respect to the reductive components.

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

Geological and geochemical studies of the Shujiadian porphyry Cu deposit, Anhui Province, Eastern China: Implications for ore genesis

NASA Astrophysics Data System (ADS)

Wang, Shiwei; Zhou, Taofa; Yuan, Feng; Fan, Yu; White, Noel C.; Lin, Fengjie

2015-05-01

Most porphyry deposits in the world occur in magmatic arc settings and are related to subduction of oceanic plates. A small proportion of porphyry deposits occur in intracontinental settings, however they are still poorly understood. Shujiadian, a newly-discovered porphyry Cu deposit, is located in the Middle-Lower Yangtze River Valley metallogenic belt and belongs to the intracontinental class. The deposit has classic alteration zones defined by a core of potassic alteration and local Ca-silicate alteration, which is overprinted by a feldspar-destructive alteration zone and cut by veins containing epidote and chlorite. Wallrocks of the deposit are unreactive quartz-rich sedimentary rocks. Three main paragenetic stages have been recognized based on petrographic observations; silicate stage, quartz-sulfide stage, and sulfide-carbonate stage. Quartz + pyrite + chalcopyrite ± molybdenite veins, and quartz + chalcopyrite + pyrite veins of the quartz-sulfide stage contribute most of the copper, and chalcopyrite + chlorite ± pyrite ± pyrrhotite ± quartz ± illite veins of the sulfide-carbonate stage also contribute part of the copper; all the mineralized veins are associated with feldspar-destructive alteration. Investigations on the fluid inclusions in Shujiadian indicate that the ore-forming fluids had four evolutionary episodes: immiscibility and overpressure in the silicate stage, boiling in the quartz-sulfide stage and mixing with meteoric water in the sulfide-carbonate stage. Sulfur and strontium isotope studies suggest that ore metals were mainly derived from magmatic-hydrothermal fluids, and combined with our study of fluid inclusions, we infer that decompression, changes in oxygen fugacity and sulfur content were the main factors that caused Cu precipitation. Compared with porphyry deposits in magmatic arc settings, there are some differences in the ore-bearing rock, alteration, and the composition of ore-forming fluids.

Some limitations on the possible composition of the ore-forming fluid

USGS Publications Warehouse

Barton, Paul B.

1956-01-01

The activity rations of various important anions (S, CO3, SO4, OH, F, and Cl) in hydrothermal solutions at the time of deposition are evaluated using a simple thermodynamic technique. The rations are interpreted in the light of the mineralogy of ore deposits and limites are placed on the variability of each ratio in hydrothermal solutions. All of the calculations are made for 25°C and cautious extrapolation to higher temperatures seems justified; however, additional data for elevated temperatures and pressures are needed before more than approximate values may be assigned to these ratios in the ore-forming fluid. The calculated partial pressure of CO2 in the ore fluid is generally less than one atmosphere, which suggests that a dense CO2 phase cannot be considered an importatn ore fluid for most deposits. The partial pressure of H2S is usually less than 10-4 atmospheres which makes it extremely difficult to defend the heory that metals (other than the easily complexible mercury, arsenic, antimony, and perhaps fols and silver) are transported in quantity as complex sulfide and hydrosulfides. The sulfate to sulfide ration is such that the oxidation potential at the time of deposition is defined by the following equation: Eh (in volts) = 0.22 ± 0.04 - 0.059 pH.

A conceptual model of the copper-porphyry ore formation based on joint analysis of deep 3D geophysical models: Sorskoe complex (Russia) case study

NASA Astrophysics Data System (ADS)

Spichak, Viacheslav V.; Goidina, Alexandra G.

2017-12-01

Joint analysis of deep three-dimensional models of the electrical resistivity, seismic velocity, and density of the complex hosting the Sorskoe Cu-Mo deposit (Russia) is carried out aimed at finding geophysical markers characterizing the areas of ore generation, transportation and deposition. The three-dimensional lithology model of the study area is built based on the empirical relationship between the silica content of the rocks and seismic velocities. It is in agreement with geological and geochemical studies provided in this area earlier and could be used as a basis for forecasting locations of the copper-molybdenum ore deposits at depth. A conceptual model of the copper-porphyry complex explaining the mechanisms of ore generation, transportation from the lower to the upper crust and deposition in the upper crust is suggested. In particular, it is supposed that post-magmatic supercritical gas-water ore-bearing fluids are upwelling through the plastic crust due to the sliding of the fluid films along the cleavage planes of the foliated rocks while at the depths of the brittle upper crust this mechanism could be changed by volumetric fluid transportation along the network of large pores and cracks.

Mineralogical and geochemical studies on the Central Seruyan Pb-Zn deposits in Central Kalimantan, Indonesia

NASA Astrophysics Data System (ADS)

Choi, Y.; Lee, I.; Choi, B.; KIM, Y.; Moon, I.

2017-12-01

The Central Seruyan Pb-Zn deposit is located in Seruyan, Central Kalimantan Province in Indonesia. This deposit has been developed since last year and is still being investigated. The Pb-Zn deposit consists of two formations, Pinoh and Kuayan formation. The former is a metamorphic unit hosting schist, phyllite and gneiss, and the latter is a pyroclastic and volcanic unit includes intermediate volcanic rocks such as dacite, tuff and breccia. Most host rocks of the deposit is composed of the silicified porphyritic dacite and silicified phyllite and covered by silicified tuff. The joints and fractures within the wall rock has E-W trends. The Seruyan Pb-Zn deposit is considered as hydrothermal breccia type.In this study, we observe ore minerals and host rocks to understand the genesis of the Pb-Zn deposit with geochemical data. Pyrite, chalcopyrite, sphalerite and galena are major ore minerals and covellite and bornite are also observed as minor sulfide minerals. These ore minerals, except pyrite, usually occur within quartz or calcite veins indicating the influence of hydrothermal fluid. In the host rocks, dacite, has the altered minerals like sericite, chlorite, epidote and some clay minerals of hydrothermal origin. All minerals occur as massive form. Only some pyrites have an euhedral form. Small amount of Au, Ag and Mo are detected in major ore minerals in the EPMA (electron probe X-ray microanalyzer) analyses.

Factors controlling localization of uranium deposits in the Dakota Sandstone, Gallup and Ambrosia Lake mining districts, McKinley County, New Mexico

USGS Publications Warehouse

Pierson, Charles Thomas; Green, Morris W.

1977-01-01

Geologic studies were made at all of the uranium mines and prospects in the Dakota Sandstone of Early(?) and Late Cretaceous age in the Gallup mining district, McKinley County, New Mexico. Dakota mines in the adjacent Ambrosia Lake mining district were visited briefly for comparative purposes. Mines in the eastern part of the Gallup district, and in the Ambrosia Lake district, are on the Chaco slope of the southern San Juan Basin in strata which dip gently northward toward the central part of the basin. Mines in the western part of the Gallup district are along the Gallup hogback (Nutria monocline) in strata which dip steeply westward into the Gallup sag. Geologic factors which controlled formation of the uranium deposits in the Dakota Sandstone are: (1) a source of uranium, believed to be uranium deposits of the underlying Morrison Formation of Late Jurassic age; (2) the accessibility to the Dakota of uranium-bearing solutions from the Morrison; (3) the presence in the Dakota of permeable sandstone beds overlain by impermeable carbonaceous shale beds; and (4) the occurrence within the permeable Dakota sandstone beds of carbonaceous reducing material as bedding-plane laminae, or as pockets of carbonaceous trash. Most of the Dakota uranium deposits are found in the lower part of the formation in marginal-marine distributary-channel sandstones which were deposited in the backshore environment. However, the Hogback no. 4 (Hyde) Mine (Gallup district) occurs in sandy paludal shale of the backshore environment, and another deposit, the Silver Spur (Ambrosia Lake district), is found in what is interpreted to be a massive beach or barrier-bar sandstone of the foreshore environment in the upper part of the Dakota. The sedimentary depositional environment most favorable for the accumulation of uranium is that of backshore areas lateral to main distributary channels, where levee, splay, and some distributary-channel sandstones intertongue with gray carbonaceous shales and siltstones of the well-drained swamp environment. Deposits of black carbonaceous shale which were formed in the poorly drained swamp deposits of the interfluve area are not favorable host rocks for uranium. The depositional energy levels of the various environments in which the sandstone and shale beds of the Dakota were deposited govern the relative favorability of the strata as uranium host rocks. In the report area, uranium usually occurs in carbonaceous sandstone deposited under low- to medium-energy fluvial conditions within distributary channels. A prerequisite, however, is that such sandstone be overlain by impermeable carbonaceous shale beds. Low- to medium-energy fluvial conditions result in the deposition of sandstone beds having detrital carbonaceous material distributed in laminae or in trash pockets on bedding planes. The carbonaceous laminae and trash pockets provide the necessary reductant to cause precipitation of uranium from solution. High-energy fluvial conditions result in the deposition of sandstones having little or no carbonaceous material included to provide a reductant. Very low energy swampy conditions result in carbonaceous shale deposits, which are generally barren of uranium because of their relative impermeability to migrating uranium-bearing solutions.

Ore microscopy of the Paoli silver-copper deposit, Oklahoma

USGS Publications Warehouse

Thomas, C.A.; Hagni, R.D.; Berendsen, P.

1991-01-01

The Paoli silver-copper deposit is located in south-central Oklahoma, 56 km south-southeast from Norman, Oklahoma. It was mined for high-grade silver-copper near the beginning of this century, and intensive exploratory drilling during the early 1970's delineated unmined portions of the deposit. A collaborative study between the U.S.G.S., the Kansas Geological Survey, and the University of Missouri-Rolla was undertaken to provide new information on the character of red bed copper deposits of the Midcontinent region. The Paoli deposit has been interpreted to occur as a roll-front type of deposit. The silver and copper mineralization occurs within paleochannels in the Permian Wellington Formation. The silver-copper interfaces appear to be controlled by oxidation-reduction interfaces that are marked by grey to red color changes in the host sandstone. Ore microscopic examinations of polished thin sections show that unoxidized ore consists of chalcocite, digenite, chalcopyrite, covellite and pyrite; and oxidized ores are characterized by covellite, bornite, hematite and goethite. In sandstone-hosted ores, chalcocite and digenite replace dolomite and border clastic quartz grains. In siltstone-hosted ores, the copper sulfide grains have varied shapes; most are irregular in shape and 5-25 ??m across, others have euhedral shapes suggestive of pyrite crystal replacements, and some are crudely spherical and are 120-200 ??m across. Chalcopyrite is the predominant copper sulfide at depth. Covellite and malachite replace chalcocite and digenite near the surface. Silver only occurs as native silver; most as irregularly shaped grains 40-80 ??m across, but some as cruciform crystals that are up to 3.5 mm across. The native silver has been deposited after copper sulfides, and locally replaces chalcocite. Surficial nodules of pyrite, malachite and hematite locally are present in outcrops at the oxidation-reduction fronts. Polished sections of the nodules show that malachite forms a cement around quartz sand grains, and brecciated pyrite grains are surrounded by rims of hematite and goethite. Dolomite is the principal sandstone cement. Cathodoluminescence microscopic study of the mineral has shown that it was deposited during seven periods before the copper sulfide mineralization. ?? 1991.

Formation of Si-Al-Mg-Ca-rich zoned magnetite in an end-Permian phreatomagmatic pipe in the Tunguska Basin, East Siberia

NASA Astrophysics Data System (ADS)

Neumann, Else-Ragnhild; Svensen, Henrik H.; Polozov, Alexander G.; Hammer, Øyvind

2017-12-01

Magma-sediment interactions in the evaporite-rich Tunguska Basin resulted in the formation of numerous phreatomagmatic pipes during emplacement of the Siberian Traps. The pipes contain magnetite-apatite deposits with copper and celestine mineralization. We have performed a detailed petrographic and geochemical study of magnetite from long cores drilled through three pipe breccia structures near Bratsk, East Siberia. The magnetite samples are zoned and rich in Si (≤5.3 wt% SiO2), Ca, Al, and Mg. They exhibit four textural types: (1) massive ore in veins, (2) coating on breccia clasts, (3) replacement ore, and (4) reworked ore at the crater base. The textural types have different chemical characteristics. "Breccia coating" magnetite has relatively low Mg content relative to Si, as compared to the other groups, and appears to have formed at lower oxygen fugacity. Time series analyses of MgO variations in microprobe transects across Si-bearing magnetite in massive ore indicate that oscillatory zoning in the massive ore was controlled by an internal self-organized process. We suggest that hydrothermal Fe-rich brines were supplied from basalt-sediment interaction zones in the evaporite-rich sedimentary basin, leading to magnetite ore deposition in the pipes. Hydrothermal fluid composition appears to be controlled by proximity to dolerite fragments, temperature, and oxygen fugacity. Magnetite from the pipes has attributes of iron oxide-apatite deposits (e.g., textures, oscillatory zoning, association with apatite, and high Si content) but has higher Mg and Ca content and different mineral assemblages. These features are similar to magnetite found in skarn deposits. We conclude that the Siberian Traps-related pipe magnetite deposit gives insight into the metamorphic and hydrothermal effects following magma emplacement in a sedimentary basin.

The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

NASA Astrophysics Data System (ADS)

Deditius, Artur P.; Reich, Martin; Kesler, Stephen E.; Utsunomiya, Satoshi; Chryssoulis, Stephen L.; Walshe, John; Ewing, Rodney C.

2014-09-01

The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ∼30 to ∼600 °C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ∼200 to ∼500 °C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and alteration by hydrothermal fluids. The second trend consists of pyrites from porphyry Cu and epithermal Au deposits, which are characterised by compositions that preserve the Au/As signature of mineralizing magmatic-hydrothermal fluids, confirming the role of this sulfide in controlling metal ratios in ore systems.

Origin of the Lengshuigou porphyry-skarn Cu deposit in the Zha-Shan district, South Qinling, central China, and implications for differences between porphyry Cu and Mo deposits

NASA Astrophysics Data System (ADS)

Xie, Guiqing; Mao, Jingwen; Wang, Ruiting; Meng, Deming; Sun, Jia; Dai, Junzhi; Ren, Tao; Li, Jianbi; Zhao, Haijie

2017-04-01

Porphyry Cu and Mo deposits are two economically important types of metal deposits worldwide, but factors controlling their difference remain enigmatic. Compared with the well-studied large porphyry Mo province in the south margin of the North China Block (S-NCB), the origin of newly discovered porphyry Cu deposits in the South Qinling (SQB) is poorly constrained. Integrated zircon LA-ICPMS U-Pb and molybdenite Re-Os ages and geological evidence indicate three stages of magmatism at Lengshuigou: (1) late Neoproterozoic (718 to 704 Ma) quartz diorite + albitite + granite association during the pre-ore stage, (2) 146 to 145 Ma granodiorite porphyry during the syn-ore stage, and (3) 145 Ma granite porphyry during the post-ore stage. Elemental and Sr-Nd isotopic evidence provide important constraints on their magma source. Pre-ore Neoproterozoic quartz diorite + albitite + granite was derived by re-melting of a mixture of crustal and juvenile mantle materials, and stronger fractional crystallization was involved in these ore-hosting intrusions than in contemporary granitoids hosted in the Douling Group. Syn-ore granodiorite porphyry was derived from mantle-derived magma with contributions from different proportions of crustal components. Post-ore granite porphyry was derived mainly from a crustal source. Nearly contemporaneous porphyry Cu and Mo systems were identified in Qinling Province, including the 147-139 Ma porphyry Mo systems in the S-NCB and 150-146 Ma porphyry Cu systems in the SQB. Granitic stocks related to porphyry Cu systems in the SQB are characterized by moderate SiO2 contents (58.01-69.07 %) and less radiogenic Nd-Hf isotopes (ɛNd(t) = -3.8 to -6.3, ɛHf(t) = -4.5 to +1.6), whereas the granitic stocks related to porphyry Mo deposits in the S-NCB have high SiO2 concentrations (64.00-76.00 %) and more radiogenic Nd-Hf isotopes (ɛNd(t) = -18.0 to -11.6, ɛHf(t) = -26.3 to -13.5). In addition, molybdenite from the Chigou and Lengshuigou porphyry Cu deposits in the S-NCB show higher Re contents (77.50-394.3 ppm) than those from nearly contemporaneous porphyry Mo deposits (9.34-49.7 ppm) in the S-NCB. These lines of evidence indicate that a higher proportion of mantle component was involved in the formation of porphyry Cu deposits in the SQB than nearly contemporaneous porphyry Mo deposits in the S-NCB. It is most likely that the nature of the magma source plays an essential role in the differences between porphyry Cu and Mo deposits.

Identifying anthropogenic uranium compounds using soft X-ray near-edge absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Jesse D.; Bowden, Mark; Tom Resch, C.

2017-01-01

Uranium ores mined for industrial use are typically acid-leached to produce yellowcake and then converted into uranium halides for enrichment and purification. These anthropogenic chemical forms of uranium are distinct from their mineral counterparts. The purpose of this study is to use soft X-ray absorption spectroscopy to characterize several common anthropogenic uranium compounds important to the nuclear fuel cycle. Non-destructive chemical analyses of these compounds is important for process and environmental monitoring and X-ray absorption techniques have several advantages in this regard, including element-specificity, chemical sensitivity, and high spectral resolution. Oxygen K-edge spectra were collected for uranyl nitrate, uranyl fluoride,more » and uranyl chloride, and fluorine K-edge spectra were collected for uranyl fluoride and uranium tetrafluoride. Interpretation of the data is aided by comparisons to calculated spectra. These compounds have unique spectral signatures that can be used to identify unknown samples.« less