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Sample records for grade uranium ores

  1. 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. PMID:23974076

  2. Photoneutron logging system for direct uranium ore-grade determination

    SciTech Connect

    Baker, M.P.; Marks, T.

    1982-06-01

    A prototype photoneutron probe for direct uranium assay in exploratory boreholes has been built and field tested. An approx. 10-Ci /sup 124/Sb gamma-ray source together with a beryllium converter is used to produce neutrons that diffuse into the surrounding formation and cause fissions in any /sup 235/U present. The fission neutrons that return to the probe are energy analyzed and counted by a high-pressure helium detector, thus indicating the concentration of uranium. The response of the probe was measured in concrete models at the US Department of Energy (Grand Junction, Colorado) calibration facility and found to be approx. 35 counts/s for an 1% U/sub 3/O/sub 8/ concentration in an 11.4-cm-diam water-filled borehole (4.5 in.). The response is linear up to a concentration of at least 0.25% by weight U/sub 3/O/sub 8/. Effects resulting from changes in formation density, porosity, and neutron absorber content were also quantified, as well as the tool response as a function of borehole diameter and fluid. A logging vehicle was outfitted, and the photoneutron-based logging system was field tested at an exploration site near Canon City, Colorado. Logging data obtained in several open holes at this site are presented and compared to core chemical analyses and results obtained in the same holes using other logging methods. In about 1 month of field testing, the photoneutron-based uranium exploration system has proved to be simple to use and very reliable. 22 figures, 12 tables.

  3. 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.

  4. PHASE ANALYSES OF URANIUM-BEARING MINERALS FROM THE HIGH GRADE ORE, NOPAL I, PENA BLANCA, MEXICO

    SciTech Connect

    M. Ren; P. Goodell; A. Kelts; E.Y. Anthony; M. Fayek; C. Fan; C. Beshears

    2005-07-11

    The Nopal I uranium deposit is located in the Pena Blanca district, approximately 40 miles north of Chihuahua City, Mexico. The deposit was formed by hydrothermal processes within the fracture zone of welded silicic volcanic tuff. The ages of volcanic formations are between 35 to 44 m.y. and there was secondary silicification of most of the formations. After the formation of at least part of the uranium deposit, the ore body was uplifted above the water table and is presently exposed at the surface. Detailed petrographic characterization, electron microprobe backscatter electron (BSE) imagery, and selected x-ray maps for the samples from Nopal I high-grade ore document different uranium phases in the ore. There are at least two stages of uranium precipitation. A small amount of uraninite is encapsulated in silica. Hexavalent uranium may also have been a primary precipitant. The uranium phases were precipitated along cleavages of feldspars, and along fractures in the tuff. Energy dispersive spectrometer data and x-ray maps suggest that the major uranium phases are uranophane and weeksite. Substitutions of Ca and K occur in both phases, implying that conditions were variable during the mineralization/alteration process, and that compositions of the original minerals have a major influence on later stage alteration. Continued study is needed to fully characterize uranium behavior in these semi-arid to arid conditions.

  5. The optimisation of stope leaching: a laboratory investigation into the extraction of uranium from a low-grade ore

    NASA Astrophysics Data System (ADS)

    Penman, Kristina Mary

    Nuclear power continues to make an important contribution to energy production in many countries around the world. Uranium mining is the first step in the production cycle of nuclear power. In order to enable low-grade uranium ore bodies to be developed as economically viable resources, low input mining techniques, such as stope leaching, are gaining interest. This thesis presents the results of research undertaken into the optimisation of stope leaching from a low grade uranium ore. Stope leaching was simulated in the laboratory by submitting crushed ore samples to successive saturated (flooding) and unsaturated (rest period) cycles. Experiments were carried out over a 52 week period using seven different protocols. The effects of rest period and lixiviant composition on uranium extraction rates were investigated. Rest period was varied by flooding at weekly, twice weekly, 2 weekly and 4 weekly intervals.. Four different lixiviants were investigated, tap water, Fe(III) sulfate, a nutrient solution and recycled leachate. Maximum uranium extractions over 52 weeks were: 57.7% for Fe(III) sulfate lixiviant with a 2 week rest period and 57.4% for tap water with a 4 week rest period. The introduction (via the lixiviant) or development (via oxidation of accessory pyrite) of low pH and Fe(III) and sulfate-rich interstitial water is thought to have provided conditions conducive to uranium oxidation and dissolution. The 4 week rest period is considered to have provided sufficient time for microbially assisted pyrite oxidation to develop similar conditions in the interstitial water as were provided by the addition of a Fe(III) sulfate lixiviant. All other protocols lead to less than 35% uranium extraction. Shorter rest periods did not allow time for sufficient pyrite oxidation to occur and the addition of a nutrient solution buffered pH which did not favour uranium dissolution. These findings have significant implications for low-grade uranium recovery by demonstrating that

  6. 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. PMID:24057960

  7. Uranium from phosphate ores

    SciTech Connect

    Hurst, F.J.

    1983-01-01

    The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant.

  8. 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.

  9. Uranium mill ore dust characterization

    SciTech Connect

    Knuth, R.H.; George, A.C.

    1980-11-01

    Cascade impactor and general air ore dust measurements were taken in a uranium processing mill in order to characterize the airborne activity, the degree of equilibrium, the particle size distribution and the respirable fraction for the /sup 238/U chain nuclides. The sampling locations were selected to limit the possibility of cross contamination by airborne dusts originating in different process areas of the mill. The reliability of the modified impactor and measurement techniques was ascertained by duplicate sampling. The results reveal no significant deviation from secular equilibrium in both airborne and bulk ore samples for the /sup 234/U and /sup 230/Th nuclides. In total airborne dust measurements, the /sup 226/Ra and /sup 210/Pb nuclides were found to be depleted by 20 and 25%, respectively. Bulk ore samples showed depletions of 10% for the /sup 226/Ra and /sup 210/Pb nuclides. Impactor samples show disequilibrium of /sup 226/Ra as high as +-50% for different size fractions. In these samples the /sup 226/Ra ratio was generally found to increase as particle size decreased. Activity median aerodynamic diameters of the airborne dusts ranged from 5 to 30 ..mu..m with a median diameter of 11 ..mu..m. The maximum respirable fraction for the ore dusts, based on the proposed International Commission on Radiological Protection's (ICRP) definition of pulmonary deposition, was < 15% of the total airborne concentration. Ore dust parameters calculated for impactor duplicate samples were found to be in excellent agreement.

  10. Method for extraction of uranium from ores

    SciTech Connect

    Bings, H.; Fischer, P.; Kampf, F.; Pietsch, H.; Thome, R.; Turke, W.; Wargalla, G.; Winkhaus, G.

    1982-11-30

    A method for continuously extracting uranium from ores comprises the steps of: forming a slurry of ore in a leaching solution; heating the slurry while pumping it through a tube reactor at high turbulences characterized by Reynolds numbers in excess of 50,000; supplying gaseous oxygen at high pressures into the tube reactor such that the uranium is substantially completely oxidized in a soluble form but impurities in the slurry are substantially kept from becoming soluble; recovering the uranium oxide solute which is substantially free of impurities.

  11. 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.

  12. 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

  13. Uranium ore rolls in the United States

    USGS Publications Warehouse

    Harshman, E.N.

    1970-01-01

    About 40% of the uranium ore reserves in the United States, minable at $8 per pound of contained U3O8, are in roll-type deposits in the State of Wyoming. The host rocks are arkosic sandstones, deposited in intermontane basins under fluvial conditions, and derived from the granitic cores of mountain ranges that flank the basins. The host rocks are Eocene and possibly Paleocene in age and are, or were, overlain by a sequence of continental tuffaceous siltstones, sandstones and conglomerates 400 - 700 m thick.

  14. Ore petrography of a sedimentary uranium deposit, Live Oak County, Texas

    SciTech Connect

    Bomber, B.J.; Ledger, E.B.; Tieh, T.T.

    1986-01-01

    Samples from the McLean 5 open-pit uranium mine, a small high-grade deposit located along a normal fault in the Miocene Oakville sandstone of Live Oak County, Texas, have been studied for uranium abundance, distribution, and nature of occurrence on the microscopic level. The host sandstone is composed of quartz, feldspars, and volcanic rock fragments, cemented by sparry calcite. Authigenic minerals include iron disulfide minerals (dominantly pyrite and some marcasite) and small amounts of clays, Ti oxides, and opal. High-grade ore (to 3% U) occurs along the fault, decreasing to less than 1,000 ppm within 10 m from the fault. The ore mineral is amorphous pitchblende and exhibits botryoidal morphology. The microscopic occurrence of uranium, documented by fission-track mapping of petrographic thin sections, is presented in detail. Uranium occurs abundantly as grain coatings and fillings in intergranular spaces in samples with high uranium content, where calcite cement has been partially or totally leached as mineralization proceeded. Lesser amounts are adsorbed onto leucoxene (microcrystalline anatase), mud clasts, and altered igneous rock fragments. Adsorbed uranium is the major code of occurrence in samples, with lower uranium contents farther from the orebody. Textural relations indicate that iron sulfides formed both before and after mineralization. Initial mineralization was by adsorption onto aggregates of fine particles of Ti oxide and clay minerals of various origins. With dissolution of cement and continued uranium influx, uranium precipitated as grain coatings and pore fillings.

  15. 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.

  16. Uranium-series disequilibrium dating of secondary uranium ore from the south Eastern Desert of Egypt.

    PubMed

    Dawood, Y H

    2001-12-01

    The secondary uranium ore of Um Ara mining area, south Eastern Desert of Egypt, is composed mainly of uranophane and beta-uranophane. They occur in the oxidized zone as idiomorphic crystals filling cavities and as coatings on the fracture surfaces of the alkali-feldspar and albitized granites. The activity ratios 234U/238U and 230Th/234U of the secondary uranium ore and host rocks indicate that there were two main phases of uranium mobility in recent geological time. An earlier precipitation of uranium from solutions forming the secondary ore and a subsequent mobilization resulted in adsorption of uranium to the host granitic rocks. The 230Th/234U age of secondary uranium ore varies from (50 +/- 10) to (159 +/- 69/-45) ka whereas, the age of uranium adsorption to the rocks ranges from (18 +/- 6) to (38 +/- 5) ka. The time of secondary uranium ore precipitation can be attributed to the Saharan II pluvial period which prevailed in Egypt during humid oxygen isotope climatic stage 5. The later uranium mobility and subsequent adsorption by the rocks took place during Kubbaniyan and Nabtian pluvial periods that coincided with oxygen isotope stages 3 and 1, respectively. PMID:11761113

  17. Supergene processes and uranium ore formation in the Ronneburg ore field, Germany

    NASA Astrophysics Data System (ADS)

    Bolonin, A. V.; Gradovsky, I. F.

    2012-04-01

    The Ordovician-Lower Carboniferous sequence of slightly metamorphosed gray carbonate-terrigenous rocks contains the Silurian black cherty shales enriched in carbon (6-9%), pyrite (6-7%), and uranium (˜30 ppm). The uranium ore is localized at the pinch-out of areal and linear zones of the Early Permian supergene (exogenic) oxidation of rocks expressed in reddening (hematitization). U, As, Sb, Cu, Ni, Mo, and Ag have been removed from the oxidized black shales and concentrated in the cementation zone in form of pitchblende and sulfides in wall-rock disseminations and veinlets largely hosted in carbonate-bearing rocks. In the Late Permian, during deposition of the upper Rotliegende and Zechstein, the fractures in the basement were filled with carbonates and sulfates; uranium was partly redeposited along with enrichment in Pb and Zn. Mesozoic and Cenozoic supergene processes altered uranium ore insignificantly.

  18. 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.

  19. Evolutionary and geological factors controlling endogenic uranium mineralization and the potential for the discovery of new ore districts

    NASA Astrophysics Data System (ADS)

    Mashkovtsev, G. A.; Miguta, A. K.; Shchetochkin, V. N.

    2015-03-01

    The exhaustion of known surface and near-surface high-grade uranium deposits poses the serious problem of prospecting and exploration of new large endogenic deposits. A comparison of large data sets for endogenic deposits from the world's major uranium districts allowed the authors to develop an evolutionary geological model of large-scale uranium ore genesis, which reflects the succession and nature of preore, ore-forming, and post-ore processes. The study reveals a combination of general (recurrent) factors controlling the formation of ore districts with large-scale uranium mineralization regardless of the genesis and timing of the mineralization. At the same time, these factors depend on the regional setting and can vary considerably among deposits of the same type localized in different tectonic blocks with different characteristics and structural evolution. In connection with this, the exploration of major genetic types of deposits requires the application of specified criteria. Along with the consideration of the evolutionary geological model of ore formation, the study discusses a variety of tectono-magmatic, mineralogical, geochemical, radiogeochemical, and physicochemical factors and indications in three uranium districts (the Streltsovskoe, Elkon, and Central Ukrainian districts), which can form the basis for further uranium prospecting and exploration. Using a combination of favorable prerequisite conditions the study compares the possibilities for the discovery of large endogenic uranium deposits in several regions of Russia.

  20. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 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 § 440.30...

  1. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 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 § 440.30...

  2. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 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 § 440.30...

  3. 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...

  4. 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 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...

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

    SciTech Connect

    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.

  6. Localization conditions and ore mineralogy of the Ulziit hydrogenic uranium deposit, Mongolia

    NASA Astrophysics Data System (ADS)

    Grechukhin, M. N.; Doinikova, O. A.; Ignatov, P. A.; Rassulov, V. A.

    2016-05-01

    Information on the speciation of uranium minerals in ore of the recently discovered Ulziit uranium deposit in Mongolia is given for the first time. The ore composition has been studied by analytical scanning electron microscopy and local laser luminescent spectroscopy. The ore formed as a result of epigenetic redox processes. Transition from permeable variegated fan sediments to poorly permeable gray-colored coalbearing lacustrine-boggy sediments is the main ore-controlling factor. High-tech uranium mining with borehole in-situ leaching is feasible.

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

    SciTech Connect

    Garralon, Antonio; Gomez, Paloma; Turrero, Maria Jesus; Buil, Belen; Sanchez, Lorenzo

    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. The 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

  8. Enumeration and characterization of microorganisms associated with the uranium ore deposit at Cigar Lake, Canada; Informal report

    SciTech Connect

    Francis, A.J.; Joshi-Tope, G.; Gillow, J.B.; Dodge, C.J.

    1994-03-01

    The high-grade uranium deposit at Cigar Lake, Canada, is being investigated as a natural analog for the disposal of nuclear fuel waste. Geochemical aspects of the site have been studied in detail, but the microbial ecology has not been fully investigated. Microbial populations in an ore sample and in groundwater samples from the vicinity of the ore zone were examined to determine their effect on uranium mobility. Counts of the total number of bacteria and of respiring bacteria were obtained by direct microscopy, and the viable aerobic and anaerobic bacteria were assessed as colony forming units (CFUs) by the dilution plating technique. In addition, the population distribution of denitrifiers, fermenters, iron- and sulfur-oxidizers, iron- and sulfate-reducers, and methanogens was determined by the most probable number (MPN) technique.

  9. RECOVERY OF URANIUM FROM LOW GRADE URANIUM BEARING ORES

    DOEpatents

    Rhodes, H.B.; Pesold, W.F.; Hirshon, J.M.

    1959-06-01

    Recovery of U, Fe, and Al from Chattanooga shale is described. Ground shale (-4 to +325 mesh) is roasted to remove organic and volatile matter. The heated shale is then reacted with a chlorinating agent (CCl/sub 4/, COCl/sub 2/, Cl, and SCl) at 600 to 1000 C. The metal chloride vapor is separated from entrained solids and then contacted with a liquid alkali metal chloride which removes U. The U is reeovered by cooling and dissolving the bath followed by acidification and solvent extraction. A condensed phase of Al, Fe, and K chlorides is treated to separate Al as alumina by passing through a Fe/sub 2/O/ sub 3/ bed. The remaining FeCl/sub 3/ is oxidized by O/sub 2/ at 1000 C to form Fe/sub 2/O/sub 3/ and Cl/sub 2/. Alternatively, vapor from the U separation step may be passed to a liquid KCl bath at 500 to 650 C. The resulting mixture is oxidized to form Cl/sub 2/ and Fe/sub 2/O/sub 3/ + Al/sub 2/O/sub 3/. The Al and Fe are separated by reaction with NaOH at high temperatures and pressures. (T.R.H.)

  10. 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

  11. 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

    2016-08-01

    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. PMID:27045621

  12. Laser-induced breakdown spectroscopy measurements of uranium and thorium powders and uranium ore

    NASA Astrophysics Data System (ADS)

    Judge, Elizabeth J.; Barefield, James E., II; Berg, John M.; Clegg, Samuel M.; Havrilla, George J.; Montoya, Velma M.; Le, Loan A.; Lopez, Leon N.

    2013-05-01

    Laser-induced breakdown spectroscopy (LIBS) was used to analyze depleted uranium and thorium oxide powders and uranium ore as a potential rapid in situ analysis technique in nuclear production facilities, environmental sampling, and in-field forensic applications. Material such as pressed pellets and metals, has been extensively studied using LIBS due to the high density of the material and more stable laser-induced plasma formation. Powders, on the other hand, are difficult to analyze using LIBS since ejection and removal of the powder occur in the laser interaction region. The capability of analyzing powders is important in allowing for rapid analysis of suspicious materials, environmental samples, or trace contamination on surfaces since it most closely represents field samples (soil, small particles, debris etc.). The rapid, in situ analysis of samples, including nuclear materials, also reduces costs in sample collection, transportation, sample preparation, and analysis time. Here we demonstrate the detection of actinides in oxide powders and within a uranium ore sample as both pressed pellets and powders on carbon adhesive discs for spectral comparison. The acquired LIBS spectra for both forms of the samples differ in overall intensity but yield a similar distribution of atomic emission spectral lines.

  13. Process of extracting both uranium and radium from uranium-containing ores

    SciTech Connect

    Nirdosh, I.; Baird, M.H.; Banerjee, S.; Muthuswami, S.V.

    1984-06-12

    Ferric chloride leaching at temperatures in the range 47-74/sup 0/C. is found to remove up to 97% of the uranium from ores occurring in the Elliot Lake area of Canada, but radium removal was found to be poor due to the formation of sulphates from the sulphides present in the ore. In processes of the invention the sulphides are initially removed by flotation, when aqueous acidic ferric chloride of relatively low concentration, e.g., 0.1 M can extract as much as 92% of the radium, giving tailings which are effectively sulphide-free and with radium levels approaching a desired maximum of 24 pCi/g. Radium may be removed by adsorption on manganese dioxide and uranium may be removed by liquid extraction with D2EHPA (DAPEX process). The ferric chloride may be recirculated for further leaching, with reduction before the uranium extraction and reoxidation afterwards. Because of the recycle, it is possible to keep chloride ion levels in the effluent below the prescribed level in Ontario, Canada of 750 ppm.

  14. A gamma-ray absorption method for the determination of uranium in ores

    USGS Publications Warehouse

    Hoyte, Alfred F.

    1957-01-01

    Current radioactivity methods used for the determination of uranium in ores are based on the assumption that secular equilibrium exists between the daughter products. Eichholz has developed a method which is claimed to be independent of the degree of equilibrium, but it has been found to be inadequate when used with some types of disequilibriated ores. An absorption method has been developed for the determination of uranium which is independent of the secular equilibrium of the series. With some refinement this method may used to determine the state of equilibrium of an ore.

  15. Uranium (-nickel-cobalt-molybdenum) mineralization along the Singhbhum copper belt, India, and the problem of ore genesis

    NASA Astrophysics Data System (ADS)

    Sarkar, S. C.

    1982-08-01

    Uranium mineralization is present at many places along the 200 km long Singhbhum copper belt, but the mineralization is relatively concentrated at the central part of it. The belt is characterized by many shear zone features, such as mylonites, phyllonites, and L-S type of structures and of course, copious metasomatism. Country rocks are basic schists, metapelites, quartzose rocks and albite schist/gneiss (‘Soda Granite’). Orebodies are sheet-like, conformable with the pervasive planar structures in the host rocks. No pronounced ‘wall rock alteration’ accompanied the mineralization. Grade of the ore is low (<0.1% U3O8). The principal uraniferous mineral uraninite occurs as dissemination. Other uranium-bearing minerals include pitchblende, allanite, xenotime, davidite, clarkeite, autunite (-metaautunite), torbernite, schoepite (-metaschoepite) and uranophane. Uranium is also present in a number of refractory phases either as inclusion of uraninite or in the crystal structure. Additionally, nickel, cobalt and molybdenum are present at Jaduguda-Bhatin in the form of millerite, gersdorffite, melonite, nickel-bearing pyrite, molybdenite etc. Dominance of uraninite over pitchblende and the larger cell-edge of uraninite, development of hematite-bearing quartz and Na-oligoclase at places in the ore zone, association of uranium mineralization with Ni-Co-Mo(-S-As) mineralization at Jaduguda-Bhatin and continuation of the orebodies to considerable depths, suggest that the uranium mineralization along the Singhbhum belt belongs to moderate to high temperature ‘vein type’. The age obtained by Pb207/Pb206 ratio and the concordia method suggest that the uranium mineralization in Singhbhum took place 1500 1600 Ma ago and this age is not far different from the age of formation of uranium-vein deposits in many other Precambrian shields of the world. The following two mechanisms of the formation of the deposits are discussed: 1) uranium precipitated in the Dhanjori basal

  16. The Gas Hills uranium district and some probable controls for ore deposition

    USGS Publications Warehouse

    Zeller, Howard Davis

    1957-01-01

    Uranium deposits occur in the upper coarse-grained facies of the Wind River formation of Eocene age in the Gas Hills district of the southern part of the Wind River Basin. Some of the principal deposits lie below the water table in the unoxidized zone and consist of uraninite and coffinite occurring as interstitial fillings in irregular blanket-like bodies. In the near-surface deposits that lie above the water table, the common yellow uranium minerals consist of uranium phosphates, silicates, and hydrous oxides. The black unoxidized uraninite -coffinite ores show enrichment of molybdenum, arsenic, and selenium when compared to the barren sandstone. Probable geologic controls for ore deposits include: 1) permeable sediments that allowed passage of ore-bearing solutions; 2) numerous faults that acted as impermeable barriers impounding the ore -bearing solutions; 3) locally abundant pyrite, carbonaceous material, and natuial gas containing hydrogen sulfide that might provide a favorable environment for precipitation of uranium. Field and laboratory evidence indicate that the uranium deposits in the Gas Hills district are very young and related to the post-Miocene to Pleistocene regional tilting to the south associated with the collapse of the Granite Mountains fault block. This may have stopped or reversed ground water movement from a northward (basinward) direction and alkaline ground water rich in carbonate could have carried the uranium into the favorable environment that induced precipitation.

  17. View looking northwest toward HIghGrade Ore Bin and Concentrate Bin ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looking northwest toward HIgh-Grade Ore Bin and Concentrate Bin - Kennecott Copper Corporation, Concentration Mill, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

  18. Uranium ore treatment. (Latest citations from the Compendex database). Published Search

    SciTech Connect

    Not Available

    1993-06-01

    The bibliography contains citations concerning the treatment of uranium ores. Emphasis is place upon the primary step within the process, acid leaching. Tailing disposal and proper handling of radioactive materials is also emphasized. Primary treatment procedures include ion-exchange, sulfuric acid leaching, solvent extraction, and sedimentation. Environmental aspects of uranium milling and mining are examined in a related bibliography. (Contains a minimum of 112 citations and includes a subject term index and title list.)

  19. Uranium ore treatment. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    Not Available

    1994-04-01

    The bibliography contains citations concerning the treatment of uranium ores. Emphasis is place upon the primary step within the process, acid leaching. Tailing disposal and proper handling of radioactive materials is also emphasized. Primary treatment procedures include ion-exchange, sulfuric acid leaching, solvent extraction, and sedimentation. Environmental aspects of uranium milling and mining are examined in a related bibliography. (Contains a minimum of 115 citations and includes a subject term index and title list.)

  20. 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.

  1. Morphology of orebodies and genesis of uranium deposits in the Khiagda ore field

    NASA Astrophysics Data System (ADS)

    Kochkin, B. T.; Novgorodtsev, A. A.; Tarasov, N. N.; Martynenko, V. G.

    2014-11-01

    The localization controls of uranium lodes at deposits in the Khiagda ore field are considered in this paper on the basis of detailed documentation of borehole cores, geological sections, and maps. Detailed mapping has been carried out at four of eight deposits of the ore field; additionally, three deposits were studied fragmentary using separate sections and boreholes. We have shown that the idea of the lenticular shape of ore-bodies in section and their ribbonlike shape in plan view only partially corresponds to reality. The revealed morphological features of orebodies along with spatial relationships with epigenetic alteration of host rocks and faults indicate that mineralization was formed by mixing of the oxygen- and uranium-bearing subsurface water descending downdip the seam and the reductive subsurface water ascending from the basement along faults. The available data on the composition of subsurface water currently contained in the basement of ore field give grounds to assume that water similar in composition could have participated in uranium ore deposition. The special properties of this water, interacting for a long time with flows of formation water under conditions of the local geological setting, have imparted those features to the studied deposits, which differentiate them from other economic sandstone-hosted deposits, including those localized in paleovalleys.

  2. Leaching of molybdenum and arsenic from uranium ore and mill tailings

    USGS Publications Warehouse

    Landa, E.R.

    1984-01-01

    A sequential, selective extraction procedure was used to assess the effects of sulfuric acid milling on the geochemical associations of molybdenum and arsenic in a uranium ore blend, and the tailings derived therefrom. The milling process removed about 21% of the molybdenum and 53% of the arsenic initially present in the ore. While about one-half of the molybdenum in the ore was water soluble, only about 14% existed in this form in the tailings. The major portion of the extractable molybdenum in the tailings appears to be associated with hydrous oxides of iron, and with alkaline earth sulfate precipitates. In contrast with the pattern seen for molybdenum, the partitioning of arsenic into the various extractable fractions differs little between the ore and the tailings. ?? 1984.

  3. Histopathologic, morphometric, and physiologic investigation of lungs of dogs exposed to uranium-ore dust

    SciTech Connect

    Cross, F.T.; Filipy, R.E.; Loscutoff, S.M.; Mihalko, P.J.; Palmer, R.F.; Busch, R.H.

    1981-01-01

    The most consistent pulmonary-function change attributed to carnotite uranium-ore-dust exposure (at 15 mg/m/sup 3/, for 4 h/day, 5 days/week) is an increased slope of the single-breath N/sub 2/ washout curve, suggesting an uneven distribution of ventilation. This change was observed in dogs exposed for less than 1 year and continued through 4 years of exposure. Measurements of pulmonary resistance, after 27, 40 and 47 months exposure, showed slight age-related changes and increasing differences between control and exposed animals with duration of exposure. These two changes are suggestive of a bronchitic response, similar to the industrial bronchitis of mine workers. The most notable pulmonary lesions observed in dogs exposed for up to 4 years are: vesicular emphysema, peribronchiolitis and focal pneumoconiosis. Lesions of the major airways and upper respiratory tract, when present, were minimal in severity. Pulmonary vesicular emphysema was present in all but one of the examined dogs. The emphysema was dose-related, in that it was present only to a slight degree in dogs exposed for less than 3 years and, thereafter, increased in severity. Morphometric measurement data confirmed the value of the histopathologic grading system for the degree of emphysema. These data correlated best with the dynamic pulmonary compliance measurements.

  4. Analysis of Concentrated Uranium Ores Using Stable Isotopes and Elemental Concentrations

    NASA Astrophysics Data System (ADS)

    Miller, D. L.; Riciputi, L. R.; Buerger, S.; Horita, J.; Bostick, D.

    2006-12-01

    The illicit trafficking of nuclear materials presents a continuing threat to national and international security. Various geochemical characteristics of yellowcake (concentrated uranium ore) could potentially provide information on the geologic, geographic, and processing origin of the ore. We have been focusing on investigating the potential of stable isotope analyses, namely carbon, nitrogen, and oxygen, to provide "forensic" information about ore environment and artificial processing methods used to concentrate the uranium ore. Stable isotope analysis of carbon and nitrogen was performed using a Costech elemental analyzer (EA) attached to a Finnigan Mat 252 mass spectrometer. Carbon and nitrogen isotopes can be characteristic of the processing agents used to concentrate the uranium ore. Oxygen analysis was performed using a ThermoFinnigan thermal conversion elemental analyzer (TCEA) attached to a Finnigan Mat 252 mass spectrometer at ORNL. In addition to the stable isotope analyses, elemental concentrations were analyzed using time-of-flight ICP-MS, and uranium isotope composition measured using MC-ICP-MS. Results from a number of yellowcake samples will be presented, illustrating the potential of geochemical characteristics to distinguish among different types of samples. Research sponsored by the Office of Nonproliferation and International Security (NA-24), National Nuclear Security Administration (NNSA), U.S. Department of Energy, under contract DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed and operated by UT-Battelle, LLC. The submitted manuscript has been authored by a contractor of the U.S. Government under contract No. DE- AC05-00OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes.

  5. Extraction of Copper from Malanjkhand Low-Grade Ore by Bacillus stearothermophilus.

    PubMed

    Singh, Sradhanjali; Sukla, Lala Behari; Mishra, Baroda Kanta

    2011-10-01

    Thermophilic bacteria are actively prevalent in hot water springs. Their potential to grow and sustain at higher temperatures makes them exceptional compare to other microorganism. The present study was initiated to isolate, identify and determine the feasibility of extraction of copper using thermophilic heterotrophic bacterial strain. Bacillus stearothermophilus is a thermophilic heterotrophic bacterium isolated from hot water spring, Atri, Orissa, India. This bacterium was adapted to low-grade chalcopyrite ore and its efficiency to solubilize copper from Malanjkhand low-grade ore was determined. The low-grade copper ore contains 0.27% Cu, in which the major copper-bearing mineral is chalcopyrite associated with other minerals present as minor phase. Variation in parameters such as pulp-density and temperatures were studied. After 30 days of incubation, it was found that Bacillus stearothermophilus solubilize copper up to 81.25% at pH 6.8 at 60°C. PMID:23024410

  6. Leaching of radionuclides from uranium ore and mill tailings ( Ra- 226, Tn-230).

    USGS Publications Warehouse

    Landa, E.R.

    1982-01-01

    The major part of the extractable uranium is associated with a readily acid-soluble fraction in both ore and tailings. The major part of the extractable 226Ra was associated with an iron, manganese hydrous-oxide fraction in the ore and tailings. Thorium-230 was the least leachable of the radionuclides studied. The major portion of the extractable 230Th was associated with alkaline-earth sulphate precipitates, organic matter, or both. The specific effects of milling on each of the nuclides are discussed.-Author

  7. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Dr. Rand Swanson

    2002-04-25

    This third quarterly technical report discusses the progress made on a machine vision technique for determining coal content and ore grades. The work done this quarter has utilized a miniature imaging spectrometer. Procedures to collect and process the spectral and spatial data from the imaging spectrometer have been established, and software routines have been employed to use this data to differentiate sulfides from background rock in platinum/palladium core samples. These sulfides are indicator minerals for high-grade platinum/palladium ore. Mappings of the sulfides generated with this procedure have been quite accurate. Samples of coal have also been obtained and preliminary measurements with the imaging spectrometer have been made.

  8. The Mechanism on Biomass Reduction of Low-Grade Manganese Dioxide Ore

    NASA Astrophysics Data System (ADS)

    Zhang, Honglei; Zhu, Guocai; Yan, Hong; Li, Tiancheng; Zhao, Yuna

    2013-08-01

    The mechanism on biomass reduction of low-grade manganese dioxide ore was studied by investigating influence factors on manganese recovery degree, such as the reaction temperature, time, biomass/ore ratio, compositions of biomass, nitrogen flow rate, and particle size of raw materials, and it was further identified through analysis of gas composition in the outlet gas, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) for the reduced sample. The results show that the reduction process involved mainly two steps: (1) The biomass was first pyrolyzed to release reductive volatiles and (2) manganese oxide ore was reacted with the reductive volatiles. By an analysis of gas composition in the outlet gas, it was also found that the ratio of biomass/ore had an important effect on the reduction mechanism. With a low biomass/ore ratio of 0.5:10, the reducing reaction of the reductive volatiles with manganese dioxide ore proceeded mainly in two stages: (1) The condensable volatiles (tar) released from biomass pyrolysis reacted with manganese oxide ore to produce reductive noncondensable gases such as hydrogen, carbon monoxide, and some light hydrocarbons; and (2) the small molecule gases further participated in the reduction. XRD pattern analysis on the reduced manganese dioxide ore revealed that the process of biomass reduction of manganese ore underwent in phases (MnO2 → Mn3O4 → MnO). The kinetics study showed the reduction process was controlled by a gas-solid reaction between biomass volatiles and manganese oxide ore with activation energy E of 53.64 kJ mol-1 and frequency factor A of 5.45 × 103 minutes-1.

  9. Effect of desliming on the magnetic separation of low-grade ferruginous manganese ore

    NASA Astrophysics Data System (ADS)

    Tripathy, Sunil Kumar; Banerjee, P. K.; Suresh, Nikkam

    2015-07-01

    In the present investigation, magnetic separation studies using an induced roll magnetic separator were conducted to beneficiate low-grade ferruginous manganese ore. The feed ore was assayed to contain 22.4% Mn and 35.9% SiO2, with a manganese-to-iron mass ratio (Mn:Fe ratio) of 1.6. This ore was characterized in detail using different techniques, including quantitative evaluation of minerals by scanning electron microscopy, which revealed that the ore is extremely siliceous in nature and that the associated gangue minerals are more or less evenly distributed in almost all of the size fractions in major proportion. Magnetic separation studies were conducted on both the as-received ore fines and the classified fines to enrich their manganese content and Mn:Fe ratio. The results indicated that the efficiency of separation for deslimed fines was better than that for the treated unclassified bulk sample. On the basis of these results, we proposed a process flow sheet for the beneficiation of low-grade manganese ore fines using a Floatex density separator as a pre-concentrator followed by two-stage magnetic separation. The overall recovery of manganese in the final product from the proposed flow sheet is 44.7% with an assay value of 45.8% and the Mn:Fe ratio of 3.1.

  10. 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.

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

    SciTech Connect

    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.

  12. Regularities of spatial association of major endogenous uranium deposits and kimberlitic dykes in the uranium ore regions of the Ukrainian Shield

    NASA Astrophysics Data System (ADS)

    Kalashnyk, Anna

    2015-04-01

    During exploration works we discovered the spatial association and proximity time formation of kimberlite dykes (ages are 1,815 and 1,900 Ga for phlogopite) and major industrial uranium deposits in carbonate-sodium metasomatites (age of the main uranium ore of an albititic formation is 1,85-1,70 Ga according to U-Pb method) in Kirovogradsky, Krivorozhsky and Alekseevsko-Lysogorskiy uranium ore regions of the Ukrainian Shield (UkrSh) [1]. In kimberlites of Kirovogradsky ore region uranium content reaches 18-20 g/t. Carbon dioxide is a major component in the formation of hydrothermal uranium deposits and the formation of the sodium in the process of generating the spectrum of alkaline ultrabasic magmas in the range from picritic to kimberlite and this is the connection between these disparate geochemical processes. For industrial uranium deposits in carbonate-sodium metasomatitics of the Kirovogradsky and Krivorozhsky uranium ore regions are characteristic of uranyl carbonate introduction of uranium, which causes correlation between CO2 content and U in range of "poor - ordinary - rich" uranium ore. In productive areas of uranium-ore fields of the Kirovogradsky ore region for phlogopite-carbonate veinlets of uranium ore albitites deep δ13C values (from -7.9 to -6.9o/oo) are characteristic. Isotope-geochemical investigation of albitites from Novokonstantynovskoe, Dokuchaevskoe, Partyzanskoe uranium deposits allowed obtaining direct evidence of the involvement of mantle material during formation of uranium albitites in Kirovogradsky ore region [2]. Petrological characteristics of kimberlites from uranium ore regions of the UkrSh (presence of nodules of dunite and harzburgite garnet in kimberlites, diamonds of peridotite paragenesis, chemical composition of indicator minerals of kimberlite, in particular Gruzskoy areas pyropes (Cr2O3 = 6,1-7,1%, MgO = 19,33-20,01%, CaO = 4,14-4,38 %, the content of knorringite component of most grains > 50mol%), chromites (Cr2O3 = 45

  13. Catalytic-Oxidative Leaching of Low-Grade Complex Zinc Ore by Cu (II) Ions Produced from Copper Ore in Ammonia-Ammonium Sulfate Solution

    NASA Astrophysics Data System (ADS)

    Liu, Zhi Xiong; Yin, Zhou Lan; Hu, Hui Ping; Chen, Qi Yuan

    2012-10-01

    The catalytic-oxidative leaching of a mixed ore, which consists of low-grade oxide copper ore and oxide zinc ore containing ZnS, was investigated in ammonia-ammonium sulfate solution. The effect of the main parameters, such as mass ratio of copper ore to zinc ore, liquid-to-solid ratio, concentration of lixivant, leaching time, and temperature, was studied. The optimal leaching conditions with a maximum extraction of Cu 92.6 pct and Zn 85.5 pct were determined as follows: the mass ratio of copper ore to zinc ore 4/10 g/g, temperature 323.15 K (50 °C), leaching time 6 hours, stirring speed 500 r/min, liquid-to-solid ratio 3.6/1 cm3/g, concentration of lixivant including ammonia 2.0 mol/dm3, ammonium sulfate 1.0 mol/dm3, and ammonium persulfate 0.3 mol/dm3. It was found that ZnS in the oxide zinc ore could be extracted with Cu(II) ion, which was produced from copper ore and was used as the catalyst in the presence of ammonium persulfate.

  14. Imaging of unconformity related uranium ore zones by crosshole ERT

    NASA Astrophysics Data System (ADS)

    Yi, M.; Kim, C.; Son, J.

    2011-12-01

    For the exploration of unconformity type uranium deposits in the Athabasca basin, Canada, electrical resistiivty survey is commonly used to define graphtic conductors in the basement. The method, however, can not provide enough resolution since the exploration target is seated in depth greater than 300 m while the width is less than 50 m. To overcome this inherent problem and introduce new exploration technology, we applied the crosshole ERT(Electrical Resistivity Tomography) technology in the Athabasca basin. Since the drillholes are not vertical and randomly oriented, 3D ERT inversion algorithm, accommodating arbitray electrode locations, was used to reconstruct 2D surbsurface resistivity image. For the 2D inversion in 3D inversion code, subsurface was assumed to be two-dimensional. We also applied the full 3D inversion to the field data set from several drillholes. In the ERT images, we could observe the graphitic pelite zone with very low resistivity which is our exploration target. By defining the accurate location of graphtic conductor, we could understand the basic setting of the site. Moreover, in the 3D ERT image, we could define anomalous zone in 3D space which can be related to the uranium target. By this introductory ERT survey, we could show that ERT can be used as a new geophysical exploration method in the Athabasca basin. In the current exploration procedure, barren drillholes are abandoned and further geophysical surveys using thes holes are rare in most cases. Since ERT technique can provide very high resolution image of the subsurface, we can have more detailed information to design the drilling program and this can lead to the cost reduction of exploration program. We expect crosshole ERT will become a standard geophysical methods in the exploration projects in the Athabasca basin.

  15. A REAL-TIME COAL CONTENT/ORE GRADE (C2OC) SENSOR

    SciTech Connect

    Rand Swanson

    2005-04-01

    This is the final report of a three year DOE funded project titled ''A real-time coal content/ore grade (C{sub 2}OG) sensor''. The sensor, which is based on hyperspectral imaging technology, was designed to give a machine vision assay of ore or coal. Sensors were designed and built at Resonon, Inc., and then deployed at the Stillwater Mining Company core room in southcentral Montana for analyzing platinum/palladium ore and at the Montana Tech Spectroscopy Lab for analyzing coal and other materials. The Stillwater sensor imaged 91' of core and analyzed this data for surface sulfides which are considered to be pathfinder minerals for platinum/palladium at this mine. Our results indicate that the sensor could deliver a relative ore grade provided tool markings and iron oxidation were kept to a minimum. Coal, talc, and titanium sponge samples were also imaged and analyzed for content and grade with promising results. This research has led directly to a DOE SBIR Phase II award for Resonon to develop a down-hole imaging spectrometer based on the same imaging technology used in the Stillwater core room C{sub 2}OG sensor. The Stillwater Mining Company has estimated that this type of imaging system could lead to a 10% reduction in waste rock from their mine and provide a $650,000 benefit per year. The proposed system may also lead to an additional 10% of ore tonnage, which would provide a total economic benefit of more than $3.1 million per year. If this benefit could be realized on other metal ores for which the proposed technology is suitable, the possible economic benefits to U.S. mines is over $70 million per year. In addition to these currently lost economic benefits, there are also major energy losses from mining waste rock and environmental impacts from mining, processing, and disposing of waste rock.

  16. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Dr. Rand Swanson

    2002-01-31

    The overall approach of this effort is to spectrally image ore or coal, and then use the spectral content (i.e., the particular colors of the ore or coal) to differentiate between the ore or coal grades. Currently, experts with practiced eyes do just this to identify the grade of platinum/palladium ore from the Stillwater Mine in south-central Montana. Additionally, trained eyes can identify high-sulfur and high-ash coal visually. The premise of this effort is that machine vision can accomplish this same differentiation. During the first quarter, machine vision results using a digital color camera did not correlate as well with assay results for platinum/palladium ore as would be required for a commercial device. One of the possible reasons for this is that the digital camera did not provide enough spectral information to obtain good differentiation between the sulfides associated with high-grade platinum/palladium ore and background interference, most notably yellow grease that contaminates some of the sample and green colored rock. The second quarter efforts have largely been devoted to implementing an imaging spectrometer for machine vision. In brief, modifying an imaging spectrometer that was designed for remote sensing from a Remotely Controlled (RC) airplane has done this. The imaging spectrometer provides 320 spectral channels, allowing for much better spectral resolution that can be obtained with a digital color camera, which provides 3 spectral channels. Preliminary results, as discussed below in more detail, are encouraging. The technical portion of the report below is organized into subsections as dictated by the DoE contract for this effort. These sections are: Experimental Apparatus, Experimental and Operating Data, Data Reduction, and Hypothesis and Conclusions. Partners in this effort are: Montana Tech of the University of Montana, Stillwater Mining Co., Western Syncoal, and the Montana Board of Research and Commercialization.

  17. Upgrading of Low-Grade Manganese Ore by Selective Reduction of Iron Oxide and Magnetic Separation

    NASA Astrophysics Data System (ADS)

    Gao, Yubo; Olivas-Martinez, M.; Sohn, H. Y.; Kim, Hang Goo; Kim, Chan Wook

    2012-12-01

    The utilization of low-grade manganese ores has become necessary due to the intensive mining of high-grade ores for a long time. In this study, calcined ferruginous low-grade manganese ore was selectively reduced by CO, which converted hematite to magnetite, while manganese oxide was reduced to MnO. The iron-rich component was then separated by magnetic separation. The effects of the various reduction parameters such as particle size, reduction time, temperature, and CO content on the efficiency of magnetic separation were studied by single-factor experiments and by a comprehensive full factorial experiment. Under the best experimental conditions tested, the manganese content in the ore increased from around 36 wt pct to more than 44 wt pct, and almost 50 wt pct of iron was removed at a Mn loss of around 5 pct. The results of the full factorial experiments allowed the identification of the significant effects and yielded regression equations for pct Fe removed, Mn/Fe, and pct Mn loss that characterize the efficiency of the upgrading process.

  18. Ore grade decrease as life cycle impact indicator for metal scarcity: the case of copper.

    PubMed

    Vieira, Marisa D M; Goedkoop, Mark J; Storm, Per; Huijbregts, Mark A J

    2012-12-01

    In the life cycle assessment (LCA) of products, the increasing scarcity of metal resources is currently addressed in a preliminary way. Here, we propose a new method on the basis of global ore grade information to assess the importance of the extraction of metal resources in the life cycle of products. It is shown how characterization factors, reflecting the decrease in ore grade due to an increase in metal extraction, can be derived from cumulative ore grade-tonnage relationships. CFs were derived for three different types of copper deposits (porphyry, sediment-hosted, and volcanogenic massive sulfide). We tested the influence of the CF model (marginal vs average), mathematical distribution (loglogistic vs loglinear), and reserve estimate (ultimate reserve vs reserve base). For the marginal CFs, the statistical distribution choice and the estimate of the copper reserves introduce a difference of a factor of 1.0-5.0 and a factor of 1.2-1.7, respectively. For the average CFs, the differences are larger for these two choices, i.e. respectively a factor of 5.7-43 and a factor of 2.1-3.8. Comparing the marginal CFs with the average CFs, the differences are higher (a factor 1.7-94). This paper demonstrates that cumulative grade-tonnage relationships for metal extraction can be used in LCA to assess the relative importance of metal extractions. PMID:23110501

  19. 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. PMID:26301831

  20. Characterization and Beneficiation Studies of a Low Grade Bauxite Ore

    NASA Astrophysics Data System (ADS)

    Rao, D. S.; Das, B.

    2014-10-01

    A low grade bauxite sample of central India was thoroughly characterized with the help of stereomicroscope, reflected light microscope and electron microscope using QEMSCAN. A few hand picked samples were collected from different places of the mine and were subjected to geochemical characterization studies. The geochemical studies indicated that most of the samples contain high silica and low alumina, except a few which are high grade. Mineralogically the samples consist of bauxite (gibbsite and boehmite), ferruginous mineral phases (goethite and hematite), clay and silicate (quartz), and titanium bearing minerals like rutile and ilmenite. Majority of the gibbsite, boehmite and gibbsitic oolites contain clay, quartz and iron and titanium mineral phases within the sample as inclusions. The sample on an average contains 39.1 % Al2O3 and 12.3 % SiO2, and 20.08 % of Fe2O3. Beneficiation techniques like size classification, sorting, scrubbing, hydrocyclone and magnetic separation were employed to reduce the silica content suitable for Bayer process. The studies indicated that, 50 % by weight with 41 % Al2O3 containing less than 5 % SiO2 could be achieved. The finer sized sample after physical beneficiation still contains high silica due to complex mineralogical associations.

  1. 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. PMID:26796528

  2. Age of uranium ores at Ranger and Jabiluka unconformity vein deposits, Northern Territory, Australia

    SciTech Connect

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

    1985-01-01

    The Ranger and Jabiluka uranium deposits are the largest in the Alligator Rivers Uranium Field (ARUF), 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 Ga Kombolgie Formation. This study uses U-Pb isotope data from over 60 whole-rock drill core samples that contained a variety of mineral assemblages and textures. Data for Ranger samples indicate a well-defined age of 1.74 +/-.02 Ga. This 1.74 Ga age is distinctly pre-Kombolgie, so the Ranger deposit cannot have been formed by processes requiring its presence. This Ranger age is consistent, however, with mineralization related to heating associated with either the emplacement of early post-metamorphic granites, or possibly with intrusion of the nearby Oenpelli Dolerite. In contrast, data for the least-altered Jabiluka ores yield a concordia-intercept age of 1.44 +/-.02 Ga--significantly younger than the Ranger age, and also younger than the Komobolgie. This age may correspond to a regional thermal event, as indicated both by mafic dikes of roughly this age and a zircon lower-intercept age from a nearby granite-gneiss. Thus, together with the well-defined approx.900 Ma age of ores at the Nabarlek deposit, there are at least 3 distinct periods of major U-mineralization in the ARUF. Data for both Ranger and Jabiluka indicate the same, profound isotopic disturbance at some time in the interval of 0.4-0.6 Ga. Possibly this time corresponds to the development of basins and associated basalt flows to the W and SW, a suggested by Crick et. al. (1980).

  3. Application of solution-mineral equilibrium chemistry to solution mining of uranium ores

    SciTech Connect

    Riese, A.C.; Propp, C.J.

    1980-01-01

    Modern methods of uranium solution mining are typically accompanied by gains and losses of mass through reagent consumption by rock-forming minerals, with subsequent formation of clay minerals, gypsum, carbonates, and iron oxyhydroxides. A systematic approach to alleviate such problems involves the application of leach solutions that are in equilibrium with the host-rock minerals but in disequilibrium with the ore-forming minerals. This partial equilibrium can be approximated by solution-composition adjustments within the systems K/sub 2/O-Al/sub 2/O/sub 3/SiO/sub 2/-H/sub 2/O and Na/sub 2/O/sub 3/-Al/sub 2/O/sub 3/SiO/sub 2/-H/sub 2/O. Uranium ore containing 0.15 percent U/sub 3/O/sub 8/ from the Gulf Mineral Resources Corporation's Mariano Lake mine, the Smith Lake district of the Grants mineral belt, was collected for investigation. Presented are a theoretical evaluation of leachate data and an experimental treatment of the ore, which contained mainly K-feldspar, plagioclase feldspar, and quartz (with lesser amounts of micas, clay minerals, and organic carbonaceous material). Small-scale (less than or equal to 1 kg) column-leaching experiments were conducted to model the results of conventional leaching operations and to provide leachate solutions that could be compared with solutions calculated to be in equilibrium with the matrix minerals. Leach solutions employed include: 1) sulfuric acid, 2) sodium bicarbonate, and 3) sulfuric acid with 1.0 molal potassium chloride. The uranium concentrations in the sodium-bicarbonate leach solution and the acid-leach solution were about a gram per liter at the termination of the tests. However, the permeability of the ore in the acid leach was greatly reduced, owing to the formation of clay minerals. Uranium solubility in the leach column stabilized with the potassium-chloride solution was calculated from leachate compositions to be limited by the solubility of carnotite.

  4. Catalytic decomposition of tar derived from wood waste pyrolysis using Indonesian low grade iron ore as catalyst

    NASA Astrophysics Data System (ADS)

    Wicakso, Doni Rahmat; Sutijan, Rochmadi, Budiman, Arief

    2016-06-01

    Low grade iron ore can be used as an alternative catalyst for bio-tar decomposition. Compared to other catalysts, such as Ni, Rd, Ru, Pd and Pt, iron ore is cheaper. The objective of this research was to investigate the effect of using low grade iron ore as catalyst for tar catalytic decomposition in fixed bed reactor. Tar used in this experiment was pyrolysis product of wood waste while the catalyst was Indonesian low grade iron ore. The variables studied were temperatures between 500 - 600 °C and catalyst weight between 0 - 40 gram. The first step, tar was evaporated at 450 °C to produce tar vapor. Then, tar vapor was flowed to fixed bed reactor filled low grade iron ore. Gas and tar vapor from reactor was cooled, then the liquid and uncondensable gas were analyzed by GC/MS. The catalyst, after experiment, was weighed to calculate total carbon deposited into catalyst pores. The results showed that the tar components that were heavy and light hydrocarbon were decomposed and cracked within the iron ore pores to from gases, light hydrocarbon (bio-oil) and carbon, thus decreasing content tar in bio-oil and increasing the total gas product. In conclusion, the more low grade iron ore used as catalyst, the tar content in the liquid decrease, the H2 productivity increased and calorimetric value of bio-oil increased.

  5. Investigation of the degree of equilibrium of the long-lived uranium-238 decay-chain members in airborne and bulk uranium-ore dusts

    SciTech Connect

    Jackson, P.O.; Thomas, C.W.

    1982-08-01

    The degree of disequilibrium among /sup 238/U decay chain members in some airborne dusts and typical ores has been established by precise radiochemical analyses. This information is necessary to evaluate the lung dose model currently used for estimating the effect of the inhalation of uranium ore dust. The particle size distributions of airborne decay chain components in dusts at one uranium mill have been investigated. Statistically significant disequilibria were observed for /sup 230/Th, /sup 226/Ra, and /sup 210/Pb in both airborne dusts and composite ore samples. With the exception of ore from one mill in the United States, most of the daughter concentrations in powdered ore composites were within 10% of /sup 238/U. In airborne dusts, the concentration of /sup 226/Ra was typically below /sup 238/U; the minimum /sup 226/Ra concentration observed for airborne ore dusts was 56% of equilibrium. A statistically significant particle size dependence was observed for /sup 226/Ra//sup 238/U ratios in several airborne dusts collected at a uranium mill.

  6. Uranium mining: ore treatment and environmental control. January 1966-May 1981 (citations from the Metals abstracts data base). Report for Jan 66-May 81

    SciTech Connect

    Not Available

    1981-05-01

    Various processes for the beneficiation of uranium bearing ores are presented. Included are acidic and bacterial leaching, chlorination, solvent extraction, and precipitation. Analytical techniques for the determination of uranium in ores and leachates, and for processes such as solution mining of deep mineral deposits, are also described. (Contains 75 citations fully indexed and including a title list.)

  7. Lacustrine-humate model for primary uranium ore deposits, Grants uranium region, New Mexico.

    USGS Publications Warehouse

    Turner-Peterson, C. E.

    1985-01-01

    It is concluded that the primary ore formation in the Morrison formation of the San Juan basin, formed during late Jurassic and early Cretaceous, was related to humic-rich pore fluids. The fluids were derived from lacustrine mud-flat facies of the Brushy basin and 'K' shales. The fluids moved into the Westwater Canyon member and the Jackpile sandstone. -K.A.R.

  8. Formation conditions of high-grade beryllium ore at the Snezhnoe deposit, Eastern Sayan

    NASA Astrophysics Data System (ADS)

    Damdinova, L. B.; Smirnov, S. Z.; Damdinov, B. B.

    2015-11-01

    The structure and formation conditions of beryllium ore, as well as the fluorite and fluorite-microcline bodies at the Snezhnoe deposit in Eastern Sayan have been revealed and studied using geological, mineralogical, petrographic, and thermobarogeochemical methods. It has been established that the stringer and breccia ores were largely formed as a result of filling of open cavities (voids and fissures) rather than of replacement of low-Ca host rocks. Three types of high-grade ore consist of almost the same set of minerals in different proportions. Calcium and fluorine necessary for fluorite formation in three main types of ore have been supplied with the near-neutral high-F solutions (type I) and the solutions of elevated alkalinity (II, III types) in the form of complex compounds like Na2CaF 4 0 , Ca2Cl3F0, etc. Beryllium minerals were deposited within a temperature interval from ≥340 to 230°C due to the cooling of the solution and binding of F into fluorite with the breakdown of Be fluorine complexes and intense deposition of Be minerals.

  9. Hyperion image analysis and linear spectral unmixing to evaluate the grades of iron ores in parts of Noamundi, Eastern India

    NASA Astrophysics Data System (ADS)

    Magendran, T.; Sanjeevi, S.

    2014-02-01

    This paper reports the results of a study to differentiate iron ores in terms of their grades, using the hyperspectral (EO-1 Hyperion) image data, covering a mineralized belt in the Noamundi area, eastern India. The study involves hyperspectral data collection, pre-processing (reduction of atmospheric and solar flux effects), generation of spectral curves from the image for the iron ore deposits, extraction of key spectral parameters and linear spectral unmixing for mapping iron ore abundance. Spectral curves for iron ore deposits extracted from the Hyperion image pixels exhibit strong absorption at 850-900 nm and 2150-2250 nm wavelengths, which is typical of iron ores. The strength of the absorption features in the continuum removed spectra varies spatially in the image around the mining areas, indicating differences in composition/grade of the iron ores. Spectral parameters such as the depth, width, area and wavelength position of the absorption features, derived from image spectra in the 850-900 nm and 2150-2250 nm regions, correlate well with the concentration of iron-oxide and alumina (gangue) in the ore samples obtained from the mine face. Well defined correlations are evident between the concentration of iron oxide and (i) the depth of NIR absorption feature (R2 = 0.883); (ii) the width of NIR absorption feature (R2 = 0.912); and (iii) the area of the NIR absorption feature and (R2 = 0.882). Further, the linear spectral unmixing resulted in an iron ore abundance map which, in conjunction with the image- and laboratory-spectra, helped in assessing the grades of iron ores in the study area. Thus, this study demonstrates the feasibility of discriminating grades of iron ores based on spectral information derived from spaceborne hyperspectral imagery.

  10. Bioleaching of heavy metals from a low-grade mining ore using Aspergillus niger.

    PubMed

    Mulligan, Catherine N; Kamali, Mahtab; Gibbs, Bernard F

    2004-07-01

    The main concern of this study is to develop a feasible and economical technique to microbially recover metals from oxide low-grade ores. Owing to the significant quantities of metals that are embodied in low-grade ores and mining residues, these are potential viable sources of metals. In addition, they potentially endanger the environment, as the metals they contain may be released to the environment in hazardous form. Hence, mining industries are seeking an efficient, economic technique to handle these ores. Pyrometallurgical and hydrometallurgical techniques are either very expensive, energy intensive or have a negative impact on the environment. For these reasons, biohydrometallurgical techniques are coming into perspective. In this study, by employing Aspergillus niger, the feasibility of recovery of metals from a mining residue is shown. A. niger exhibits good potential in generating a variety of organic acids effective for metal solubilization. Organic acid effectiveness was enhanced when sulfuric acid was added to the medium. Different agricultural wastes such as potato peels were tested. In addition, different auxiliary processes were evaluated in order to either elevate the efficiency or reduce costs. Finally, maximum solubilization of 68%, 46% and 34% were achieved for copper, zinc and nickel, respectively. Also iron co-dissolution was minimized as only 7% removal occurred. PMID:15177728

  11. 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.

  12. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Rand Swanson

    2004-01-23

    This tenth quarterly technical report discusses the progress made on a machine vision technique for ore grading based on hyperspectral imaging. A graduate student at Montana Tech has successfully defended her thesis related to this project. Arrangements with Stillwater Mining Company to deploy a machine vision system in their core room have been completed. Designs for they system that will be installed next quarter have been drawn and parts are being machined. Presentations on the spectral imaging system developed during this effort have been made to Stillwater Mining Company and at a remote sensing symposium at Montana State University.

  13. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Dr. Rand Swanson

    2003-04-28

    This seventh quarterly technical report discusses the progress made on a machine vision technique for determining coal content and ore grades. Considerable progress has been made on coal analysis. Naval Research Laboratory (NRL) target recognition software has been tested and incorporated into the system. This software decreases analysis time considerably and is more intuitive to use. Work with board-level computers has proceeded well; ultimately this will make the technology more compact and fieldable. Work with talc will be delayed because the graduate student working on this project is leaving the program. Ongoing work is devoted to more detailed coal analysis, improving the software interface, and developing procedures and a users manual.

  14. Use of mesophilic and thermophilic bacteria for the improvement of copper extraction from a low-grade ore

    NASA Astrophysics Data System (ADS)

    Darezereshki, E.; Schaffie, M.; Lotfalian, M.; Seiedbaghery, S. A.; Ranjbar, M.

    2011-04-01

    Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.

  15. Mineralogical and Beneficiation Studies of a Low Grade Iron Ore Sample

    NASA Astrophysics Data System (ADS)

    Dwari, R. K.; Rao, D. S.; Reddy, P. S. R.

    2014-10-01

    Investigations were carried out, to establish its amenability for physical beneficiation on a low grade siliceous iron ore sample by magnetic separation. Mineralogical studies, with the help of microscope as well as XRD, SEM-EDS revealed that the sample consists of magnetite, hematite and goethite as major opaque oxide minerals where as quartz and kaolinite form the gangue minerals in the sample. Processes involving combination of classification, dry magnetic separation and wet magnetic separation were carried out to upgrade the low grade siliceous iron ore sample to make it suitable as a marketable product. The sample was first ground and each closed size sieve fractions were subjected to dry magnetic separation and it was observed that limited upgradation is possible. The ground sample was subjected to different finer sizes and separated by wet low intensity magnetic separator. Dry beneficiation studies by Permaroll separator indicated that it is possible to get a product with 60.2 % Fe at 22 % weight recovery. It is possible to get an over all concentrate with 54 % Fe at 32.4 % weight recovery by combination of size reduction followed by LIMS and WHIMS.

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

    DOE PAGESBeta

    Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael; Robel, Martin; Williams, Ross; Lindvall, Rachel; Eppich, Gary; Roberts, Sarah; Borg, Lars; Gaffney, Amy; et al

    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

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

    SciTech Connect

    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

    2014-04-13

    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 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.

  18. 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. PMID:24836840

  19. Detailed mineral and chemical relations in two uranium-vanadium ores

    USGS Publications Warehouse

    Garrels, Robert M.; Larsen, E. S., III; Pommer, A.M.; Coleman, R.G.

    1956-01-01

    Channel samples from two mines on the Colorado Plateau have been studied in detail both mineralogically and chemically. A channel sample from the Mineral Joe No. 1 mine, Montrose County, Colo., extends from unmineralized rock on one side, through a zone of variable mineralization, into only weakly mineralized rock. The unmineralized rock is a fairly clean quartz sand cemented with gypsum and contains only minor amounts of clay minerals. One boundary between unmineralized and mineralized rock is quite sharo and is nearly at right angles to the bedding. Vanadium clay minerals, chiefly mixed layered mica-montmorillonite and chlorite-monmorillonite, are abundant throughout the mineralized zone. Except in the dark "eye" of the channel sample, the vanadium clay minerals are accompanied by hewettite, carnotite, tyuyamunite, and probably unidentified vanadates. In the dark "eye," paramontroseite, pyrite, and marcasite are abundant, and bordered on each side by a zone containing abundant corvusite. No recognizable uranium minerals were seen in the paramontroseite zone although uranium is abundant there. Coaly material is recognizable throughout all of the channel but is most abundant in and near the dark "eye." Detailed chemical studies show a general increase in Fe, Al, U, and V, and a decrease in SO4 toward the "eye" of the channel. Reducing capacity studies indicate that V(IV) and Fe(II) are present in the clay mineral throughout the channel, but only in and near the "eye" are other V(IV) minerals present (paramontroseite and corvusite). The uranium is sexivalent, although its state of combination is conjectural where it is associated with paramontroseite. Where the ore boundary is sharp, the boundary of introduced trace elements is equally sharp. Textural and chemical relations leave no doubt that the "eye: is a partially oxidized remnant of a former lower-valence ore, and the remainder of the channel is a much more fully oxidized remnant. A channel sample from the

  20. Schneeberg lung disease and uranium mining in the Saxon Ore Mountains (Erzgebirge).

    PubMed

    Schüttmann, W

    1993-02-01

    The so-called Schneeberg lung disease is a form of bronchial or alveolar carcinoma caused by the effects of the radioactive gas radon and of its radioactive short half-life daughter products. This type of radiation-induced occupational cancer is the most common and the most important radiation injury among workers occupationally exposed to ionizing radiation. There have been many deaths from lung cancer, especially in the Soviet uranium mines in the Erzgebirge of Saxony in the former German Democratic Republic. The history of disease in these miners extends over five centuries; the first observations of their health hazard start in the Middle Ages. The discovery of the lung cancer component was made toward the end of the nineteenth century, and the suspicion that a connection might exist between this cancer type and exposure to ionizing radiation was voiced at the beginning of the twentieth century. In the first half of this century, further research was carried out on this disease in the Schneeberg area of the Erzgebirge. Before the end of World War II, guidelines were set up to define the acceptable limits of radon exposure in the ore mines of Saxony. After World War II, the American uranium mines in the Colorado Plateau used the German research results as a basis for working out their own radiation protection standard. The uranium mines under Soviet occupation in the former GDR, on the contrary, paid no attention to these research findings. For many years, no precautions were taken for the miners' working conditions. The consequence of this serious omission was an estimated 9,000 fatal cases of lung cancer among these underground miners. High concentrations of radon are to be found in indoor air of homes in some districts of the Erzgebirge, suggesting an increasing lung cancer risk for the local inhabitants. The significance of this finding is evaluated. PMID:8427263

  1. Comparison of the isotopic abundance of U235 and U238 and the radium activity ratios in Colorado Plateau uranium ores

    USGS Publications Warehouse

    Senftle, F.E.; Stieff, L.; Cuttitta, F.; Kuroda, P.K.

    1957-01-01

    The isotopic abundances of uranium and the radium activity ratios of eleven samples of uranium ore from the Colorado Plateau have been measured. No significant variation in the isotopic abundance of the uranium was noted; with'in the experimental error, the average U235/U238 ratio is 137.7. There is a significant variation in the Ra226/Ra223 activity ratios (0.048-0.143), which indicates a relatively recent alteration of the ore samples. The variations do not, however, explain the lead-uranium and lead-lead age discrepancies. ?? 1957.

  2. Application of visible/near-infrared reflectance spectroscopy to uranium ore concentrates for nuclear forensic analysis and attribution.

    PubMed

    Klunder, Gregory L; Plaue, Jonathan W; Spackman, Paul E; Grant, Patrick M; Lindvall, Rachel E; Hutcheon, Ian D

    2013-09-01

    Uranium ore concentrates (UOCs) are produced at mining facilities from the various types of uranium-bearing ores using several processes that can include different reagents, separation procedures, and drying conditions. The final UOC products can consist of different uranium species, which are important to identify to trace interdicted samples back to their origins. Color has been used as a simple indicator; however, visual determination is subjective and no chemical information is provided. In this work, we report the application of near-infrared (NIR) spectroscopy as a non-contact, non-destructive method to rapidly analyze UOC materials for species and/or process information. Diffuse reflectance spectra from 350 to 2500 nm were measured from a number UOC samples that were also characterized by X-ray diffraction. Combination and overtone bands were used to identify the amine and hydroxyl-containing species, such as ammonium uranates or ammonium uranyl carbonate, while other uranium oxide species (e.g., uranium trioxide [UO3] and triuranium octoxide [U3O8]) exhibit absorption bands arising from crystal field effects and electronic transitions. Principal component analysis was used to classify the different UOC materials. PMID:24067636

  3. 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

  4. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Dr. Rand Swanson

    2002-10-24

    This fifth quarterly technical report discusses the progress made on a machine vision technique for determining coal content and ore grades. Recent work has been devoted to implementing new hardware and examining defects in titanium sponge, a new application for the machine vision system. With the improvements in hardware and software, the data collection is much improved. Early results from data taken on titanium sponge defects indicate that some defects will be relatively easy to identify, but others will be much more difficult. Consequently, additional work is required with software algorithms for target recognition. Ongoing work will be divided into several fronts, which include data collection and analysis, improving the target recognition capabilities, and improving the electronic interface.

  5. Size distribution of aerosol particles produced during mining and processing uranium ore.

    PubMed

    Mala, Helena; Tomasek, Ladislav; Rulik, Petr; Beckova, Vera; Hulka, Jiri

    2016-06-01

    The aerosol particle size distributions of uranium and its daughter products were studied and determined in the area of the Rožná mine, which is the last active uranium mine in the Czech Republic. A total of 13 samples were collected using cascade impactors from three sites that had the highest expected levels of dust, namely, the forefield, the end of the ore chute and an area close to workers at the crushing plant. The characteristics of most size distributions were very similar; they were moderately bimodal, with a boundary approximately 0.5 μm between the modes. The activity median aerodynamic diameter (AMAD) and geometric standard deviation (GSD) were obtained from the distributions beyond 0.39 μm, whereas the sizes of particles below 0.39 μm were not differentiated. Most AMAD and GSD values in the samples ranged between 3.5 and 10.5 μm and between 2.8 and 5.0, respectively. The geometric means of the AMADs and GSDs from all of the underground sampling sites were 4.2 μm and 4.4, respectively, and the geometric means of the AMADs and GSDs for the crushing plant samplings were 9.8 μm and 3.3, respectively. The weighted arithmetic mean of the AMADs was 4.9 μm, with a standard error of 0.7 μm, according to the numbers of workers at the workplaces. The activity proportion of the radon progeny to (226)Ra in the aerosol was 0.61. PMID:27032340

  6. Molecular analysis of bacterial communities in uranium ores and surrounding soils from Banduhurang open cast uranium mine, India: A comparative study.

    PubMed

    Islam, Ekramul; Dhal, Paltu K; Kazy, Sufia K; Sar, Pinaki

    2011-01-01

    Bacterial community structure of heavy metal rich- uranium ores and surrounding soils was explored using 16S rRNA gene based clone library analysis and denaturing gradient gel electrophoresis (DGGE) to provide baseline microbial diversity data on autochthonous communities. Sequence analysis of major ribotypes and/or DGGE bands revealed Proteobacteria and Acidobacteria as the two most frequently present bacterial phyla across the samples, although relative abundance of each phyla and identity of their members at lower taxonomic level showed marked difference. Gammaproteobacteria (Pseudomonas and Escherichia) was most abundant in U-ore samples along with the lineages of β-Proteobacteria (Burkholderia and Janthinobacterium), α-Proteobacteria (Brevundimonas), Bacteroidetes (Spingobacterium), Firmicutes (Peptoniphilus), Actinobacteria (Corynebacterium), uncultured -Acidobacteria, -Chloroflexi and -Cyanobacterium. In contrast to this soil communities were represented by mixed populations predominated by uncultured Acidobacteria along with Gammaproteobacteria (Succinivibrio, Cellovibrio and Legionella), β-Proteobacteria (Rhodocyclus), α-Proteobacteria (Methylocystis and Phenylobacterium), δ-Proteobacteria, unclassified bacteria, uncultured Bacteroidetes, Firmicutes (Bacillus), Cyanobacteria (Scytonema), Actinobacteria (Actinomadura) and candidate division TM7. Principle Component Analyis (PCA) of geochemical data and UPGMA cluster analysis of DGGE profiles were in close agreement showing characteristic relatedness of samples obtained from either ores or soils. Our analysis indicated that soils surrounding the ore deposit bear specific geochemical as well as microbiologial characteristics distinct from the ore deposit and therefore these data obtained at the onset of mining could serve as a baseline of information to gauge the subsequent environmnetal impact of U-mining. PMID:21308598

  7. Cesium and strontium tolerant Arthrobacter sp. strain KMSZP6 isolated from a pristine uranium ore deposit.

    PubMed

    Swer, Pynskhem Bok; Joshi, Santa Ram; Acharya, Celin

    2016-12-01

    Arthrobacter sp. KMSZP6 isolated from a pristine uranium ore deposit at Domiasiat located in North-East India exhibited noteworthy tolerance for cesium (Cs) and strontium (Sr). The strain displayed a high minimum inhibitory concentration (MIC) of 400 mM for CsCl and for SrCl2. Flow cytometric analysis employing membrane integrity indicators like propidium iodide (PI) and thiazole orange (TO) indicated a greater sensitivity of Arthrobacter cells to cesium than to strontium. On being challenged with 75 mM of Cs, the cells sequestered 9612 mg Cs g(-1) dry weight of cells in 12 h. On being challenged with 75 mM of Sr, the cells sequestered 9989 mg Sr g(-1) dry weight of cells in 18 h. Heat killed cells exhibited limited Cs and Sr binding as compared to live cells highlighting the importance of cell viability for optimal binding. The association of the metals with Arthrobacter sp. KMSZP6 was further substantiated by Field Emission-Scanning Electron Microscopy (FE-SEM) coupled with Energy dispersive X-ray (EDX) spectroscopy. This organism tolerated up to 1 kGy (60)Co-gamma rays without loss of survival. The present report highlights the superior tolerance and binding capacity of the KMSZP6 strain for cesium and strontium over other earlier reported strains and reveals its potential for bioremediation of nuclear waste. PMID:27620733

  8. Analysis of the risk of transporting uranium ore concentrates by truck

    SciTech Connect

    Geffen, C.A.

    1981-07-01

    This report evaluates the risks involved with shipping uranium ore concentrates by truck in an attempt to provide some perspective on the system safety issues. The basic probabilistic risk evaluation methodology used in this study is similar to that employed by Pacific Northwest Laboratory (PNL) in a series of risk analyses on the transportation of potentially hazardous energy materials. The risk model has been constructed as a series of separate analysis steps to allow the system risk to be readily reevaluated as additional data become available or as postulated system characteristics change. The reslts of this analysis show that the risks to the public health and safety from yellowcake releases during a transportation accident are insignificant. Accidents involving truck shipments of yellowcake are expected to occur at a rate of about ten a year. However, only one-fifth of these accidents, or about two a year, are expected to cause a release of yellowcake to the environment. None of these accidents was estimated to produce any potential fatalities. The low concentration of radioactivity distributed throughout the material resulted in no significant increase in radiation doses above normal background levels to members of the general public.

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

    SciTech Connect

    Marks, N. E.; Borg, L. E.; Eppich, G. R.; Gaffney, A. M.; Genneti, V. G.; Hutcheon, I. D.; Kristo, M. J.; Lindvall, R. E.; Ramon, C.; Robel, M.; Roberts, S. K.; Schorzman, K. C.; Sharp, M. A.; Singleton, M. J.; Williams, R. W.

    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.

  10. Metabolism of uranium in the rat after inhalation of two industrial forms of ore concentrate: the implications for occupational exposure.

    PubMed

    Stradling, G N; Stather, J W; Gray, S A; Moody, J C; Ellender, M; Hodgson, A; Sedgwick, D; Cooke, N

    1987-09-01

    Aerosols produced from two commercially available ore concentrates in which the uranium was present essentially in the one as ammonium diuranate (ADU) and in the other as uranium octoxide (U3O8) were administered to rats. The results show that: 1 uranium in the ADU bearing material was cleared rapidly from the lungs, mainly to the blood, such that the retention kinetics were similar to those for a class D (highly transportable) compound as defined by ICRP; 2 uranium in the U3O8 bearing material was removed from the lungs principally by mechanical processes, the retention kinetics in this case being similar to those defined for a class Y (poorly transportable) compound; 3 for both materials the distribution of uranium amongst body tissues and the fraction of the systemic content excreted in urine were similar to those obtained after the injection of soluble hexavalent compounds; 4 for workers potentially exposed to both these materials, urine monitoring and lung radioactivity counting measurements should be used in addition to air sampling procedures for assessing the intake of uranium. 5 intakes of the ADU bearing material should be restricted to those permitted for short-term exposures on the basis of chemical toxicity, whereas those for the U3O8 bearing material should be governed by radiation dose. PMID:3679246

  11. The formation of technic soil in a revegetated uranium ore waste rock pile (Limousin, France)

    NASA Astrophysics Data System (ADS)

    Boekhout, Flora; Gérard, Martine; Kanzari, Aisha; Calas, Georges; Descostes, Michael

    2014-05-01

    Mining took place in France between 1945 and 2001 during which time ~210 different sites were exploited and/or explored. A total of 76 Kt of uranium was produced, 52 Mt of ore was extracted, but also 200 Mt of waste rocks was produced, the majority of which, with uranium levels corresponding to the natural environment. So far, the processes of arenisation and technic soil formation in waste rock piles are not well understood but have important implications for understanding the environmental impact and long-term speciation of uranium. Understanding weathering processes in waste rock piles is essential to determine their environmental impact. The main objectives of this work are to assess 1) the micromorphological features and neo-formed U-bearing phases related to weathering and 2) the processes behind arenisation of the rock pile. The site that was chosen is the Vieilles Sagnes waste rock pile in Fanay (Massif Central France) that represents more or less hydrothermally altered granitic rocks that have been exposed to weathering since the construction of the waste rock pile approximately 50 years ago. Two trenches were excavated to investigate the vertical differentiation of the rock pile. This site serves as a key location for studying weathering processes of waste rock piles, as it has not been reworked after initial construction and has therefore preserved information on the original mineralogy of the waste rock pile enabling us to access post emplacement weathering processes. The site is currently overgrown by moss, meter high ferns and small trees. At present day the rock pile material can be described as hydrothermally altered rocks and rock fragments within a fine-grained silty clay matrix exposed to surface conditions and weathering. A sandy "paleo" technic soil underlies the waste rock pile and functions as a natural liner by adsorption of uranium on clay minerals. Post-mining weathering of rock-pile material is superimposed on pre-mining hydrothermal and

  12. Radon and radioactivity at a town overlying Uranium ores in northern Greece

    NASA Astrophysics Data System (ADS)

    Kourtidis, Konstantinos; Georgoulias, Aristeidis; Tsirliganis, Nestor

    2016-04-01

    Extensive measurements of Rn-222 in the town of Xanthi in N Greece show that the part of the town overlying granite deposits and the outcrop of a uranium ore has exceptionally high indoor radon levels, with monthly means up to 1500 Bq m-3. A large number of houses (40%) in this part of the town exhibit radon levels above 200 Bq m-3 while 11% of the houses had radon levels above 400 Bq/m3. Substantial interannual variability as well as the highest in Europe winter/summer ratios (up to 12) were observed in this part of the town, which consist of traditional stone masonry buildings of the late 19th- early 20th century. Measurements of U-238 and Th-232 content of building materials from these houses as well as radionuclide measurements in different floors show that the high levels of indoor radon measured in these buildings are not due to high radon emanation rates from the building materials themselves but rather due to high radon flux from the soil because of the underlying geology, high radon penetration rates into the buildings from underground due to the lack of solid concrete foundations in these buildings, or a combination thereof. From the meteorological variables studied, highest correlation with indoor Rn-222 was found with temperature (r2=0.65). An indoor radon prognostic regression model using temperature, pressure and precipitation as input was developed, that reproduced indoor radon with r2=0.69. Hence, meteorology is the main driving factor of indoor radon, with temperature being the most important determinant. Preliminary flux measurements indicate that the soil-atmosphere Rn-222 flux should be in the range 150-250 Bq m-2 hr-1, which is in the upper 10% of flux values for Europe.

  13. Radon and radioactivity at a town overlying Uranium ores in northern Greece.

    PubMed

    Kourtidis, K; Georgoulias, A K; Vlahopoulou, M; Tsirliganis, N; Kastelis, N; Ouzounis, K; Kazakis, N

    2015-12-01

    Extensive measurements of (222)Rn in the town of Xanthi in N Greece show that the part of the town overlying granite deposits and the outcrop of a uranium ore has exceptionally high indoor radon levels, with monthly means up to 1500 Bq m(-3). A large number of houses (40%) in this part of the town exhibit radon levels above 200 Bq m(-3) while 11% of the houses had radon levels above 400 Bq m(-3). Substantial interannual variability as well as the highest in Europe winter/summer ratios (up to 12) were observed in this part of the town, which consist of traditional stone masonry buildings of the late 19th-early 20th century. Measurements of (238)U and (232)Th content of building materials from these houses as well as radionuclide measurements in different floors show that the high levels of indoor radon measured in these buildings are not due to high radon emanation rates from the building materials themselves but rather due to high radon flux from the soil because of the underlying geology, high radon penetration rates into the buildings from underground due to the lack of solid concrete foundations in these buildings, or a combination thereof. From the meteorological variables studied, highest correlation with indoor (222)Rn was found with temperature (r(2) = 0.65). An indoor radon prognostic regression model using temperature, pressure and precipitation as input was developed, that reproduced indoor radon with r(2) = 0.69. Hence, meteorology is the main driving factor of indoor radon, with temperature being the most important determinant. Preliminary flux measurements indicate that the soil-atmosphere (222)Rn flux should be in the range 150-250 Bq m(-2) h(-1), which is in the upper 10% of flux values for Europe. PMID:26372739

  14. 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.

  15. Uranium Chemical and Radiological Risk Assessment for Freshwater Ecosystems Receiving Ore Mining Releases: Principles, Equations and Parameters

    SciTech Connect

    Beaugelin-Seiller, K.; Garnier-Laplace, J.; Gilbin, R.; Adam, C.

    2008-08-07

    Uranium is an element that has the solely characteristic to behave as significant hazard both from a chemical and radiological point of view. Exclusively of natural occurrence, its distribution into the environment may be influenced by human activities, such as nuclear fuel cycle, military use of depleted uranium, or coal and phosphate fertilizer use, which finally may impact freshwater ecosystems. Until now, the associated environmental impact and risk assessments were conducted separately. We propose here to apply the same methodology to evaluate the ecological risk due to potential chemotoxicity and radiotoxicity of uranium. This methodology is articulated into the classical four steps (EC, 2003: problem formulation, effect and exposure analysis, risk characterisation). The problem formulation dealt both with uranium viewed as a chemical element and as the three isotopes 234, 235 and 238 of uranium and their main daughters. Then, the exposure analysis of non-human species was led on the basis of a common conceptual model of the fluxes occurring in freshwater ecosystems. No-effect values for the ecosystem were derived using the same effect data treatment in parallel. A Species Sensitivity Distribution was fitted: (1) to the ecotoxicity data sets illustrating uranium chemotoxicity and allowing the estimation of a Predicted-No-Effect-Concentration for uranium in water expressed in {mu}g/L; (2) to radiotoxicity effect data as it was done within the ERICA project, allowing the estimation of a Predicted No-Effect-Dose-Rate (in {mu}Gy{center_dot}h{sup -1}). Two methods were then applied to characterize the risk to the ecosystem: a screening method using the risk quotient approach, involving for the radiological aspect back calculation of the water limiting concentration from the PNEDR for each isotope taken into account and a probabilistic risk assessment. A former uranium ore mining case-study will help in demonstrating the application of the whole methodology.

  16. Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

    NASA Astrophysics Data System (ADS)

    Lin, Qing-quan; Gu, Guo-hua; Wang, Hui; Zhu, Ren-feng; Liu, You-cai; Fu, Jian-gang

    2016-05-01

    In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfuric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leaching efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sulfuric acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respectively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent activation energy of 12.28 kJ·mol-1. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSO4·H2O.

  17. Measurement of uranium series radionuclides in rock and groundwater at the Koongarra ore deposit, Australia, by gamma spectrometry

    SciTech Connect

    Yanase, Nobuyuki; Sekine, Keiichi

    1995-12-31

    Gamma spectrometry without any self-absorption correction was developed to measure low energy gamma rays emitted by uranium and actinium series radionuclides in rock samples and groundwater residues collected at the Koongarra ore deposit, Australia. Thin samples were prepared to minimize the self-absorption by uranium in the samples. The present method gave standard deviations of 0.9 to 18% for the measurements of concentrations of uranium and actinium series radionuclides. The concentrations of {sup 238}U, {sup 230}Th and {sup 235}U measured by gamma spectrometry were compared with those by alpha spectrometry that requires a complicated chemical separation procedure. The results obtained by both methods were in fairly good agreement, and it was found that the gamma spectrometry is applicable to rock and groundwater samples having uranium content sup to 8.1% (10{sup 3} B1/g) and 3 Bq/l of {sup 238}U, respectively. The detection limits were calculated to be of the order of 10{sup {minus}2} Bq/g for rock samples and 10{sup {minus}1} Bq/l for groundwater samples. The concentrations of uranium and actinium series radionuclides can be determined precisely in these samples using gamma spectrometry without any self-absorption correction.

  18. 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.

  19. In-situ leaching of South Texas uranium ores - 2. Oxidative removal of adsorbed ammonium ions with sodium hypochlorite

    SciTech Connect

    Paul, J.M.; Johnson, W.F.; Fletcher, A.; Venuto, P.B.

    1981-01-01

    This paper reports a laboratory study of the oxidative destruction, by sodium hypochlorite, of ammonium ions adsorbed on relatively reduced South Texas uranium ore. Included are an assessment of reaction stoichiometry, determination of some major reaction pathways and side reactions, and identification of several intermediates. Adsorbed ammonium ions were completely removed by 0.5% sodium hypochlorite with the concentration of ammonia in the effluent falling to a very low value after 10-15 pore volumes of the oxidant. Substantial quantities of sulfate, reflecting oxidation of sulfide minerals such as pyrite, were formed. Large amounts of uranium were leached out, and substantial amounts of calcium and magnesium ions were also produced during the pre-saturation with ammonium bicarbonate during the oxidation stage. 28 refs.

  20. Geology and geochemistry of the Macheng Algoma-type banded iron-formation, North China Craton: Constraints on mineralization events and genesis of high-grade iron ores

    NASA Astrophysics Data System (ADS)

    Wu, Huaying; Niu, Xianglong; Zhang, Lianchang; Pirajno, Franco; Luo, Huabao; Qin, Feng; Cui, Minli; Wang, Changle; Qi, Min

    2015-12-01

    The Macheng iron deposit is located in the eastern Hebei province of the North China Craton (NCC). It is hosted in Neoarchean metamorphic rocks of Baimiaozi formation in the Dantazi Group, consisting of biotite-leptynite, plagioclase-gneiss, plagioclase-amphibolite, migmatite, migmatitic granite and quartz schist. Geochemical analyses of the host biotite leptynite and plagioclase amphibolites show that their protoliths are both volcanics, inferred to be trachytic basalt and basaltic andesite, respectively. Based on the geochemical signature of the host rocks, together with geology of the iron deposit, it is inferred that the Macheng BIF is an Algoma-type iron exhalative formation, formed in an arc-related basin in the Neoarchean. Post-Archean Australian Shale (PAAS)-normalized rare earth elements (REEs) plus yttrium (Y) concentrations of different BIF ores with gneissic, striated and banded structure in the Macheng deposit, show similar patterns with depletions in light rare earth elements (LREEs) and middle rare earth elements (MREEs) relative to heavy rare earth elements (HREEs) and with apparently positive La, Y and Eu anomalies. Y/Ho ratios of the gneissic, striated and banded BIF ores vary from 37 to 56. These geochemical features of the BIF ores reveal their affinity with the sea water and the presence of a high-temperature hydrothermal component, indicating that both the seawater and high temperature hydrothermal fluids derived from alteration of oceanic basalts and komatiites may contribute to formation of the Macheng BIF. Geological, mineralogical and geochemical studies of the Macheng deposit recognized two kinds of high-grade iron ores. One is massive oxidized high-grade ore (Fe2O3T = 74.37-86.20 wt.%), mainly consisting of hematite with some magnetite, which shows geochemical characteristics of the gneissic, striated and banded BIF ores. The other type is magnetite high-grade ore, also massive and consisting of magnetite, with distinct characteristics

  1. Effects of Sodium Citrate on the Ammonium Sulfate Recycled Leaching of Low-Grade Zinc Oxide Ores

    NASA Astrophysics Data System (ADS)

    Yang, Kun; Li, Shi-wei; Zhang, Li-bo; Peng, Jin-hui; Ma, Ai-yuan; Wang, Bao-bao

    2016-03-01

    The effects of sodium citrate on ammonium sulfate recycled leaching of low-grade zinc oxide ores were studied. By applying various kinds of detection and analysis techniques such as chemical composition analysis, chemical phase method, scanning electron microscopy and energy dispersive spectrum (SEM/EDS), X-ray diffraction (XRD) and Fourier-transforming infrared spectrum (FT-IR), zinc raw ore, its leaching slag and the functional mechanism of sodium citrate were investigated. Based on a comprehensive analysis, it can be concluded that in contrast to hemimorphite (Zn4Si2O7(OH)2 · H2O), amorphous smithsonite (ZnCO3) and zinc silicate (Zn2SiO4) prove to be refractory phases under ammonium sulfate leaching, while sodium citrate has a better chelating action with the refractory phases, resulting in a higher zinc leaching rate. Under conditions of [NH3]/[NH3]T molar ratio being 0.5, [NH3]T being 7.5 mol/L, [Na3C6H5O7] being 0.2 mol/L, S/L ratio being 1:5, temperature being 303 K, holding time being 1 h in each of the two stages, and stirring rate being 300 rpm, the leaching rate of zinc reached 93.4%. In this article, sulfate ammonium recycled technology also reveals its unique advantage in processing low-grade zinc oxide ores accompanied by high silicon and high alkaline gangue.

  2. (234)U/(238)U signatures associated with uranium ore bodies: part 2 Manyingee.

    PubMed

    Lowson, Richard T; McIntyre, Mark G

    2013-04-01

    The Manyingee ore body is a roll-front U ore body located at depth in the Cretaceous sandstone sediments of a Proterozoic palaeo valley. It is located in a confined aquifer. The aquifer is recharged 4 km upstream by the Ashburton River. Groundwater samples were collected at and up to 4.7 km downstream of the ore body. The ground water (234)U/(238)U activity ratios (AR) were elevated to 1.86 in the vicinity of the ore body and then declined to 1.06 over the 4.7 km transect. The elevated (234)U/(238)U ARs are attributed to selective leaching of (234)U sites by oxidising waters, with α recoil as a necessary precursor to produce activated (234)U sites. Direct ejection into another phase following α recoil is considered to be a minor contributor to (234)U -(238)U disequilibrium in this environment. The profile is considered to be typical of the (234)U/(238)U AR profile at and down gradient of the redox front of a U ore body. PMID:23182403

  3. (234)U/(238)U signatures associated with uranium ore bodies: part 3 Koongarra.

    PubMed

    Lowson, Richard T

    2013-04-01

    The Koongarra ore body is an early Proterozoic U ore body in the Alligator Rivers U province, Northern Territory, Australia. It has surface expression with a redox front located ∼30 m below the surface. The (234)U/(238)U activity ratios (AR) for the ground water and the amorphous phase of the solid have been analysed for the ore zone and dispersion halo as a function of depth. The results display a (234)U/(238)U AR signature with depth which may be common to all U ore bodies. The (234)U/(238)U AR is depressed below secular equilibrium in the weathered material above the redox front; rises significantly above secular equilibrium in the vicinity of the redox front; and is followed by a gradual decrease with depth below the redox front. The amplitude of the profile is a function of local conditions. A model is proposed for the signature in which oxidising waters preferentially leach the (234)U sites at the redox front due to preconditioning of the (234)U sites by α recoil during the decay of (23)(8)U to (23)(4)U. Mass balance requires the solid material left behind the redox front to have a (234)U/(238)U AR reduced below 1. Local second order effects may be superimposed on the signature. The signature may have application to calibrating scenarios for nuclear waste repositories, assisting in understanding historical climates, economic evaluation of U ore bodies and U exploration. PMID:23142336

  4. High-grade iron ore deposits of the Mesabi Range, Minnesota-product of a continental-scale proterozoic ground-water flow system

    USGS Publications Warehouse

    Morey, G.B.

    1999-01-01

    The Mesabi Range along the north edge of the Paleoproterozoic Penokean orogen in northern Minnesota has produced 3.6 billion metric tons of ore since its discovery in 1890. Of that amount, 2.3 billion metric tons were extracted from hematite- or geothite-rich deposits generally referred to as 'high-grade' ores. The high-grade ores formed as the Biwabik Iron-Formation was oxidized, hydrated, and leached by solutions flowing along open faults and fractures. The source of the ore-forming solutions has been debated since it was first proposed that the ores were weathering products formed by descending meteoritic ground-water flowing in late Mesozoic time. Subsequently others believed that the ores were better explained by ascending solutions, possbily hydrothermal solutions of pre-Phanerzoic age. Neither Wolff nor Gruner could reconcile their observations with a reasonable source for the solutions. In this paper, I build on modern mapping of the Mesabi Range and mine-specific geologic observations summarized in the literature to propose a conceptual model in which the high-grade ores formed from ascending solutions that were part of continent-scale topographic or gravity-driven ground-water system. I propose that the ground-water system was active during the later stages of the development of a coupled fold and thrust belt and foreland basin that formed during the Penokean orogen.

  5. Genesis and formation conditions of deposits in the unique Strel'tsovka Molybdenum-Uranium ore field: New mineralogical, geochemical, and physicochemical evidence

    NASA Astrophysics Data System (ADS)

    Aleshin, A. P.; Velichkin, V. I.; Krylova, T. L.

    2007-10-01

    The ambiguity of genetic interpretations of uranium ore formation at Mo-U deposits of the Strel’tsovka ore field led us to perform additional geochemical, mineralogical, and thermobarogeochemical studies. As a result, it has been established that closely related U and F were progressively gained in the Late Mesozoic volcanic rocks from the older basic volcanics (170 Ma) to the younger silicic igneous rocks (140 Ma). The Early Cretaceous postmagmatic hydrothermal epoch (140-125 Ma) is subdivided into preore, uranium ore, and first and second postore stages. The primary brannerite-pitchblende ore was formed in association with fluorite. At the first postore stage, this assemblage was replaced by a U-Si metagel, which was previously identified as coffinite. The metagel shows a wide compositional variation; its fine structure has been studied. The preore metasomatic alteration and related veined mineralization were formed under the effect of sodium (bicarbonate)-chloride solution at a temperature of 250-200°C. The uranium ore formation began with albitization and hematitization of rocks affected by supercritical fluid at 530-500°C; brannerite and pitchblende precipitated at 350-300°C. The chondrite-normalized REE patterns of pitchblende hosted in trachybasalt, trachydacite, and granite demonstrate a pronounced Sm-Nd discontinuity and a statistically significant tetrad effect of W type. These attributes were not established in REE patterns of rhyolites derived from the upper crustal magma chamber. This circumstance and a chronological gap of 5 Ma between silicic volcanism and ore formation do not allow us to suggest that uranium was derived from this magma chamber. According to the proposed model, the evolved silicic Li-F magma was a source of uranium. U4+, together with REE, was fractionated into the fluid phase as complex fluoride compounds. The uranium mineralization was deposited at a temperature barrier. It is suggested that hydromica alteration and the

  6. Thermogravimetric Analysis and Kinetics on Reducing Low-Grade Manganese Dioxide Ore by Biomass

    NASA Astrophysics Data System (ADS)

    Zhang, Honglei; Zhu, Guocai; Yan, Hong; Li, Tiancheng; Feng, Xiujuan

    2013-08-01

    Nonisothermal thermogravimetric analysis (TGA) was applied to evaluate rice straw, sawdust, wheat stalk, maize straw, and bamboo to explore their potential for reduction of manganese dioxide ore. Results from the biomass pyrolysis experiments showed that wood-based biomass materials, such as sawdust and bamboo, could produce more reductive agents, while herb-based biomass materials, such as rice straw, wheat stalk, and maize straw, had lower reaction temperatures. The peak temperatures for biomass reduction tests were 20 K to 50 K (20 °C to 50 °C) higher compared with the pyrolysis tests, and a clear shoulder at around 523 K (250 °C) could be observed. The effects of heating rate, biomass/manganese dioxide ore ratio, and different components of biomass were also investigated. An independent parallel first-order reaction kinetic model was used to calculate the values of activation energy and frequency factor for biomass pyrolysis and reduction of manganese dioxide ore. For better understanding the reduction process, kinetic parameters of independent behavior of manganese dioxide ore were also calculated by simple mathematical treatment. Finally, the isokinetic temperature T i and the rate constant k 0 for reduction of manganese oxide ore by reductive volatiles of biomass were derived according to the Arrhenius equation, which were determined to be 603 K (330 °C) and 108.99 min-1, respectively.

  7. Column bioleaching of low-grade mining ore containing high level of smithsonite, talc, sphaerocobaltite and azurite.

    PubMed

    Ilyas, Sadia; Chi, Ruan; Bhatti, H N; Bhatti, I A; Ghauri, M A

    2012-03-01

    Present work describes the bioleaching potential of metals from low-grade mining ore containing smithsonite, sphaerocobaltite, azurite and talc as main gangue minerals with adapted consortium of Sulfobacillus thermosulfidooxidans strain-RDB and Thermoplasma acidophilum. Bioleaching potential improved markedly by added energy source, acid preleaching and adaptation of microbial consortium with mixed metal ions. During whole leaching period including acid preleaching stage of 960 h and bioleaching stage of 212 days about 76% Co, 70% Zn, 84% Cu, 72% Ni and 63% Fe leached out. PMID:21947702

  8. 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

  9. 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. PMID:23793914

  10. Key parameters for low-grade fine-grained iron ore valorization: lower environmental impact through reduced waste.

    NASA Astrophysics Data System (ADS)

    Wagner, Christiane; Orberger, Beate; Tudryn, Alina; Baptiste, Benoît; Wirth, Richard; Morgan, Rachel; Miska, Serge

    2016-04-01

    In low-grade banded iron formations (BIFs), a large part of the iron is related to micro- and nano- metric iron-bearing inclusions within quartz and/or carbonates, mainly dolomite (~ 20 to 50 μm). Low-grade fine grained iron ore present two types of environmental risks: a) they are often stocked as tailings. For example, the recent disaster (5th of November 2015) in the Minas Gerais district, Brazil, was caused by the collapse of the Fundão tailings dam at an open cast mine; b) during beneficiation significant amounts of dust are generated also leading to metal loss. A laminated BIF studied from a drill core at Àguas Claras Mine, Quadrilátero Ferrífero, Brazil, contains 26.71 wt. % total iron, 0.2 wt. % SiO2, 0.32 wt.% MnO, 15.46 wt. % MgO, 22.32 wt.% CaO, 0.09 wt. % P2O5, < 0.05 wt. % Al2O3, 0.15 wt. % H2O and 34.08 wt. % CO2. Environmental hazardous elements are present as traces (As: 3-20 ppm, Cd: 0-0.7 ppm; Cr: 0.05-60 ppm, Pb: up to 55 ppm; U: up to 8 ppm). Dolomite and quartz bands alternate with hematite bands. Raman spectroscopy, X-ray diffraction and FIB-TEM analyses reveal that the micro- and nano- metric inclusions in dolomite are hematite and minor goethite, partly occurring as clusters in voids. Curie Balance analyses were carried out at different heating steps and temperatures on whole rock samples and a synthetic mix of decarbonated sample and pure dolomite. X-ray diffraction on the products of the heating experiments shows that that hematite is stable and new phases: magnesioferrite (MgFe2O4), lime (CaO), periclase (MgO), portlandite (Ca(OH)2) and srebrodoskite (Ca2Fe2O5) were formed between 680 °C and 920 °C. These findings promote the economic use of low grade ores rather than their stockpiling as tailings. The presence of OH-bearing goethite reduces the sintering temperature. After having separated coarse hematite from barren dolomite and quartz, a low temperature sintering of the inclusion-bearing dolomite/quartz leads to transformations

  11. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Dr. Rand Swanson

    2003-07-21

    This eighth quarterly technical report discusses the progress made on a machine vision technique for determining coal content and preparations for Year-3 system deployment. Classification maps for coal have been generated and shown to two coal-mining executives. An application for licensing high-speed hyperspectral data analysis software from the Naval Research Laboratory (NRL) has been made. Both Western Energy and Stillwater Mining Company have offered platforms for Year-3 deployment. Barretts Minerals has expressed renewed interest in using Resonon's machine vision system for identifying dolomite in their talc ore and have agreed to provide samples to the Montana Tech team.

  12. Hydrothermal alteration of organic matter in uranium ores, Elliot Lake, Canada: Implications for selected organic-rich deposits

    SciTech Connect

    Mossman, D.J.; Nagy, B.; Davis, D.W.

    1993-07-01

    Organic matter in the uraniferous Matinenda Formation, Elliot Lake, is preserved in the forms of syngenetic kerogen and solid bitumen as it is in many of the Oklo uranium deposits and in the Witwatersrand gold-uranium ores. The Elliot Lake kerogen is a vitrinite-like material considered to be remnants of the Precambrian cyanobacterial mats. The kerogen at Elliot Lake has reflectances (in oil) ranging from 2.63-7.31% RO{sub max}, high aromaticity, relatively low (0.41-0.60) atomic H/C ratios, and it contains cryptocrystalline graphite. Bitumen, present primarily as dispersed globules (up to 0.5 mm dia.), has reflectances from 0.72-1.32% RO{sub max}, atomic H/C ratios of 0.71-0.81, and is somewhat less aromatic than the kerogen. Overall similarity in molecular compositions indicates that liquid bitumen was derived from kerogen by processes similar to hydrous pyrolysis. The carbon isotopic composition of kerogen ({minus}15.62 to {minus}24.72%), and the now solid bitumen ({minus}25.91 to {minus}33.00%) are compatible with these processes. Despite having been subjected to several thermal episodes, ca. 2.45 Ga old kerogen of microbiological origin here survived as testimony of the antiquity of life on Earth. U-Pb isotopic data from discrete kerogen grains at Elliot Lake form a scattered array intersecting concordia at 2130 {+-} 100 Ma, correspond to the Nipissing event. U-Pb systems were totally reset by this event. Uranium and lead show subsequently partial mobility, the average of which is indicated by the lower concordia intersect of 550 {+-} 260 Ma. The migrated bitumen contains virtually no uranium and thorium but has a large excess of {sup 206}Pb, which indicates that the once liquid bitumen must have acted as a sink for mobile intermediate decay products of {sup 238}U. Emplacement of the Nipissing diabase may have been responsible for producing the bitumen and, indirectly, for its enrichment in {sup 206}Pb as a result of outgassing of {sup 222}Rn.

  13. Reductive leaching of manganese from low-grade pyrolusite ore in sulfuric acid using pyrolysis-pretreated sawdust as a reductant

    NASA Astrophysics Data System (ADS)

    Feng, Ya-li; Zhang, Shi-yuan; Li, Hao-ran

    2016-03-01

    Manganese (Mn) leaching and recovery from low-grade pyrolusite ore were studied using sulfuric acid (H2SO4) as a leachant and pyrolysis-pretreated sawdust as a reductant. The effects of the dosage of pyrolysis-pretreated sawdust to pyrolusite ore, the concentration of sulfuric acid, the liquid/solid ratio, the leaching temperature, and the leaching time on manganese and iron leaching efficiencies were investigated. Analysis of manganese and iron leaching efficiencies revealed that a high manganese leaching efficiency was achieved with low iron extraction. The optimal leaching efficiency was determined to be 20wt% pyrolysis-pretreated sawdust and 3.0 mol/L H2SO4 using a liquid/ solid ratio of 6.0 mL/g for 90 min at 90°C. Other low-grade pyrolusite ores were tested, and the results showed that they responded well with manganese leaching efficiencies greater than 98%.

  14. Stratification Studies with Sub Grade Iron Ore from Deposit No. 10 and 11A, Bacheli Complex, Bailadila, Chhattisgarh, India

    NASA Astrophysics Data System (ADS)

    Venkateswara Rao, Gottumukkala; Markandeya, Ravvala; Sharma, Satish Kumar

    2016-06-01

    Experiments were carried out with two different sizes of (-30 + 6 and -6 + 1 mm) sub grade iron ore sample from Deposit No. 10 and 11A, Bacheli Complex, Bailadila, India to study the stratification behaviour at optimised parameters in a under bed air pulsed jig at 1, 2, 5, 10, 15 and 20 minutes residence time. This paper deals with the rate at which stratification takes place and determines the optimum stratification time (residence time) for above two size fractions. Average apparent density along with Jig Stratification Index (JSI) of both the size fractions was calculated. It was observed that the stratification rate is high for fines (-6 + 1 mm) and stratification index was higher for lump (-30 + 6 mm) when compared with the other size fraction. The maximum JSI observed was 0.35 for lump (-30 + 6 mm) and 0.30 for fines (-6 + 1 mm).

  15. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Rand Swanson

    2003-04-27

    This eleventh quarterly technical report discusses the installation of a spectral machine vision system in the Stillwater mine's core room. In brief, the system has been fabricated, installed, and preliminary measurements have been made. A first round of refinements has been made, included replacing a bad bearing and applying filters to the lighting. A high-speed Spectral Angle Mapper (SAM) program was written to classify the cores in real time. This program identifies sulfides in the core sample quite well, but also produces false positives at boundaries and breaks in the core. Additionally, bright reflections from facets within the ore occasionally saturate the camera. Overall, the project is on schedule, but additional refinement in the algorithm and lighting is required to obtain more accurate results.

  16. A REAL TIME COAL CONTENT ORE GRADE (C2OG) SENSOR

    SciTech Connect

    Rand Swanson

    2004-10-22

    This thirteenth quarterly technical report describes data collection at the Stillwater Mine and an additional improvement to the lighting system. The data collection system was returned to the Stillwater Mine during this reporting period and a large amount of data was collected. The data will be analyzed and correlated with fire assays in the next reporting period. The majority of work done this quarter has been devoted to collecting data from cores scanned in the Stillwater Mining Company core room. This work is somewhat tedious and tiresome, but essential to: (1) obtain enough data to reliably determine the correlation between assay results and spectral imaging results; (2) find bugs and glitches in the system that arise only periodically or after long periods of use; and (3) obtain data on the natural (and man-made) variations in the Stillwater ore that may confuse the machine vision algorithms.

  17. Preliminary study on weapon grade uranium utilization in molten salt reactor miniFUJI

    SciTech Connect

    Aji, Indarta Kuncoro; Waris, A.

    2014-09-30

    Preliminary study on weapon grade uranium utilization in 25MWth and 50MWth of miniFUJI MSR (molten salt reactor) has been carried out. In this study, a very high enriched uranium that we called weapon grade uranium has been employed in UF{sub 4} composition. The {sup 235}U enrichment is 90 - 95 %. The results show that the 25MWth miniFUJI MSR can get its criticality condition for 1.56 %, 1.76%, and 1.96% of UF{sub 4} with {sup 235}U enrichment of at least 93%, 90%, and 90%, respectively. In contrast, the 50 MWth miniFUJI reactor can be critical for 1.96% of UF{sub 4} with {sup 235}U enrichment of at smallest amount 95%. The neutron spectra are almost similar for each power output.

  18. 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.

  19. Tectonic breccias--conduits for ore-bearing and metasomatic fluids in the Jabiluka unconformity-type uranium-gold deposit, Northern Territory, Australia

    SciTech Connect

    Nutt, C.J.; Grauch, R.I.

    1985-01-01

    The distribution of strata-bound uranium ore in the highly chloritized Early Proterozoic metasedimentary rocks at Jabiluka, Australia, is controlled by shear zones associated with repeated episodes of brittle deformation. Based on extensive study of drill-hole core, the authors proposed tectonic control of ore distribution contrasts with most previous Jabiluka models that emphasize carbonate solution and collapse as the primary cause of brecciation. The strata-bound character of the ore, which is predominantly in chlorite, chlorite+graphite, and siliceous breccias, is a function of the susceptibility of specific rock types to shear and fracture. The siliceous breccias, which may in part be preferentially brecciated and silicified magnesite and dolomite, commonly contain fragments of sheared and strained quartz in recrystallized quartz matrix. Mineralized schist fragments and broken uraninite veins in breccias indicate that some of the brecciation occurred after a major mineralizing event. Brecciated zones and fractures are cemented and filled by quartz and by Mg-rich chlorite and 7A amesite. The presence of at least three generations of quartz in siliceous breccias and a number of optically, and in some cases chemically, distinguishable chlorites in chlorite breccias indicates that repeated pulses of fluids moved through the broken rocks. The circulation of these fluids redistributed and possibly further concentrated preexisting ore.

  20. Magnetic and flotation studies of banded hematite quartzite (BHQ) ore for the production of pellet grade concentrate

    NASA Astrophysics Data System (ADS)

    Das, B.; Mishra, B. K.; Prakash, S.; Das, S. K.; Reddy, P. S. R.; Angadi, S. I.

    2010-12-01

    To identify and establish beneficiation techniques for banded hematite quartzite (BHQ) iron ore, a comprehensive research on BHQ ore treatment was carried out. The BHQ ore was assayed as 38.9wt% Fe, 42.5wt% SiO2, and 1.0wt% Al2O3. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 μm. The rejection of silica particles can be obtained by magnetic and flotation separation techniques. Overall, the BHQ ore can be enriched to 65.3wt% Fe at 61.9% iron recovery. A flowsheet has been suggested for the commercial exploitation of the BHQ ore.

  1. In-situ leaching of south Texas uranium ores--part 2: oxidative removal of adsorbed ammonium ions with sodium hypochlorite

    SciTech Connect

    Paul, J.M.; Fletcher, A.; Johnson, W.F.; Venuto, P.B.

    1983-04-01

    This paper reports a laboratory study of the oxidative destruction by sodium hypochlorite (NaOCl) of ammonium ions adsorbed on relatively reduced south Texas uranium ore. Included are an assessment of reaction stoichiometry, determination of some major reaction pathways and side reactions, and identification of several intermediates. Adsorbed ammonium ions were completely removed by 0.5% NaOCl, with the concentration of NH/sub 3/ in the effluent falling to a very low value after 10 to 15 PV NaOCl oxidant. A small fraction (5 to 10%) of NaOCl was utilized in reacting with NH/sub 3/. After the NH/sub 3/ was nearly depleted, mono-, di-, and trichloramines, the expected intermediates in NaOCl oxidation of NH/sub 3/, were observed. Chloramine decomposition studies showed that all three decomposed completely within 12 days. Since the ore was relatively highly reducing, the major part of the NaOCl was, not unexpectedly, consumed in side reactions. Substantial quantities of sulfate, reflecting oxidation of sulfide minerals such as pyrite, were formed, large amounts of uranium were leached out, and substantial amounts of calcium and magnesium ions were also produced during the presaturation with NH/sub 4/HCO/sub 3/ preceding the oxidation stage.

  2. In-situ leaching of south Texas uranium ores--part 2: Oxidative removal of adsorbed ammonium ions with sodium hypochlorite

    SciTech Connect

    Paul, J.M.; Fletcher, A.; Johnson, W.F.; Venuto, P.B.

    1983-04-01

    This paper reports a laboratory study of the oxidative destruction by sodium hypochlorite (NaOCl) of ammonium ions adsorbed on relatively reduced south Texas uranium ore. Included are an assessment of reaction stoichiometry, determination of some major reaction pathways and side reactions, and identification of several intermediates. Adsorbed ammonium ions were completely removed by 0.5% NaOCl, with the concentration of NH/sub 3/ in the effluent falling to a very low value after 10 to 15 PV NaOCl oxidant. A small fraction (5 to 10%) of NaOCl was utilized in reacting with NH/sub 3/. After the NH/sub 3/ was nearly depleted, mono-, di-, and trichloramines, the expected intermediates in NaOCl oxidation of NH/sub 3/, were observed. Chloramine decomposition studies showed that all three decomposed completely within 12 days. Since the ore was relatively highly reducing, the major part of the NaOCl was, not unexpectedly, consumed in side reactions. Substantial quantities of sulfate, reflecting oxidation of sulfide minerals such as pyrite, were formed, large amounts of uranium were leached out, and substantial amounts of calcium and magnesium ions were also produced during the presaturation with NH/sub 4/HCO/sub 3/ preceding the oxidation stage.

  3. Occurrence of copper, gold, silver,uranium, tungsten, tin ore deposits in the Late Proterozoic aulacogen mobile melt of southeast China

    SciTech Connect

    Ma, X.H.

    1985-01-01

    In the early period of the late Proterozoic Era (1100 m.y. +/-) an aulacogen mobile belt was formed in the southeast of China. It extends about 1000 km crossing the Yantze Platform and Jiangnan Foldbelt in NNE-NE direction and adjoins the south China geosyncline basement. This belt shows some features of geology and mineralization similar to the Adelaide geosyncline and the Zambia-Zaire Copper-uranium belt. Within the belt, there are about 9000 to 12,000 m polystratotype strata and continuous sediments of the Late Proterozoic Erathem, including alkaline and meta-alkaline volcanic products of 4 epochs of mainly marine facies. A great number of ore-forming elements, such as Cu, U, Pb, Zn, Au, Ag, Fe, Co, Ni, Mn, P, and W, Sn, TR etc., were deposited and enriched in the whole volcano-sedimentary sequency at various times and in various places. A few of them have become syngenetic deposits, but most of them have been transformed into large-scale ore deposits or mineralization fields or areas of copper and gold, lead-zinc and silver, uranium, tungsten, tin, and other metals.

  4. X-ray energy dispersive spectroscopy of uranium ore using a TES microcalorimeter mounted on a field-emission scanning electron microscope

    NASA Astrophysics Data System (ADS)

    Maehata, Keisuke; Idemitsu, Kazuya; Tanaka, Keiichi

    2011-08-01

    Energy dispersive spectroscopic measurements of uranium ore were conducted using a superconducting phase transition-edge-thermosensor (TES) microcalorimeter mounted on a field-emission scanning electron microscope (SEM) to demonstrate its potential for high-precision microanalysis. The effective solid angle for X-ray detection is found to be larger than 2 msr by precise adjustments in the X-ray polycapillary alignment. The observed detection signal pulses with decay time constant of 50 μs enable maximum count rates larger than 300 counts per second. The energy resolution was determined to be 14.6 eV FWHM at Al Kα X-ray energies of 1487 eV. Distinct peaks appear in the resulting X-ra y energy spectrum associated with U-Mα, U-Mβ and U-Mγ X-rays emitted by the uranium ore specimens. This spectrum includes weaker peaks corresponding to C-Kα, Fe-Lα, Cu-L and Sr L α1 X rays.

  5. Optimization of staged bioleaching of low-grade chalcopyrite ore in the presence and absence of chloride in the irrigating lixiviant: ANFIS simulation.

    PubMed

    Vakylabad, Ali Behrad; Schaffie, Mahin; Naseri, Ali; Ranjbar, Mohammad; Manafi, Zahra

    2016-07-01

    In this investigation, copper was bioleached from a low-grade chalcopyrite ore using a chloride-containing lixiviant. In this regard, firstly, the composition of the bacterial culture media was designed to control the cost in commercial application. The bacterial culture used in this process was acclimated to the presence of chloride in the lixiviant. Practically speaking, the modified culture helped the bio-heap-leaching system operate in the chloridic media. Compared to the copper recovery from the low-grade chalcopyrite by bioleaching in the absence of chloride, bioleaching in the presence of chloride resulted in improved copper recovery. The composition of the lixiviant used in this study was a modification with respect to the basal salts in 9 K medium to optimize the leaching process. When leaching the ore in columns, 76.81 % Cu (based on solid residues of bioleaching operation) was recovered by staged leaching with lixiviant containing 34.22 mM NaCl. The quantitative findings were supported by SEM/EDS observations, X-ray elemental mapping, and mineralogical analysis of the ore before and after leaching. Finally, Adaptive neuro-fuzzy inference system (ANFIS) was used to simulate the operational parameters affecting the bioleaching operation in chloride-sulfate system. PMID:27000968

  6. Attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum cultured under varying conditions to pyrite, chalcopyrite, low-grade ore and quartz in a packed column reactor.

    PubMed

    Africa, Cindy-Jade; van Hille, Robert P; Harrison, Susan T L

    2013-02-01

    The attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum spp. grown on ferrous medium or adapted to a pyrite mineral concentrate to four mineral substrata, namely, chalcopyrite and pyrite concentrates, a low-grade chalcopyrite ore (0.5 wt%) and quartzite, was investigated. The quartzite represented a typical gangue mineral and served as a control. The attachment studies were carried out in a novel particle-coated column reactor. The saturated reactor containing glass beads, which were coated with fine mineral concentrates, provided a quantifiable surface area of mineral concentrate and maintained good fluid flow. A. ferrooxidans and Leptospirillum spp. had similar attachment characteristics. Enhanced attachment efficiency occurred with bacteria grown on sulphide minerals relative to those grown on ferrous sulphate in an ore-free environment. Selective attachment to sulphide minerals relative to gangue materials occurred, with mineral adapted cultures attaching to the minerals more efficiently than ferrous grown cultures. Mineral-adapted cultures showed highest levels of attachment to pyrite (74% and 79% attachment for A. ferrooxidans and L. ferriphilum, respectively). This was followed by attachment of mineral-adapted cultures to chalcopyrite (63% and 58% for A. ferrooxidans and L. ferriphilum, respectively). A. ferrooxidans and L. ferriphilum exhibited lower levels of attachment to low-grade ore and quartz relative to the sulphide minerals. PMID:22410741

  7. Early Jurassic mafic dykes from the Xiazhuang ore district (South China): Implications for tectonic evolution and uranium metallogenesis

    NASA Astrophysics Data System (ADS)

    Wang, Lian-Xun; Ma, Chang-Qian; Lai, Zhong-Xin; Marks, Michael A. W.; Zhang, Chao; Zhong, Yu-Fang

    2015-12-01

    A comprehensive study on zircon U-Pb age dating, whole-rock geochemistry and Sr-Nd isotope data has been conducted on the mafic rocks of the Xiazhuang uranium ore district and adjacent regions in South China. Based on field work and petrographic features, three rock types (the Kuzhukeng gabbro, the WNW-trending dolerite dykes and the NNE-trending lamprophyre dykes) are distinguished. Early Jurassic SHRIMP and LA-ICPMS ages of zircon for the Kuzhukeng gabbro (198 ± 1 Ma) and WNW-trending dolerite dykes (193 ± 4 Ma) have been obtained, which are 50 Ma older than previously thought (being Cretaceous). These geochronologic data provide new evidence for the rarely identified Early Jurassic magmatisms in South China. Whole-rock geochemical data for the Kuzhukeng gabbro and WNW-trending dolerite dykes are similar, both of which being higher in FeO and TiO2 but lower in SiO2 and K2O than the NNE-trending lamprophyre dykes. Trace element characteristics and Sr-Nd isotope data indicate arc-like signatures similar to the Cretaceous southeast coast basalts of China for the lamprophyre dykes, but an OIB-like geochemical affinity for the high-TiO2 mafic rocks similar to the Permo/Triassic Emeishan flood basalts and the Middle Jurassic Ningyuan alkaline basalts. We propose that the lamprophyre dykes formed in an arc volcanic system driven by the subduction of the paleo-Pacific plate. In contrast, the Kuzhukeng gabbro and associated dolerite dykes record the post-orogenic (Indosinian) extension event in the Tethyan tectonic regime. This further implies that the Indosinian extension may have lasted until the Early Jurassic, and therefore, the subduction of the paleo-Pacific plate in south China was probably later than this period. Most U deposits of the Xiazhuang area are located at the intersection between the WNW-trending dolerite dykes and the NNE-trending faults within the Triassic granites of eastern Guidong complex, South China. Previous metallogenesis studies assumed that

  8. 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.

  9. Proliferation dangers associated with nuclear medicine: getting weapons-grade uranium out of radiopharmaceutical production.

    PubMed

    Williams, Bill; Ruff, Tilman A

    2007-01-01

    Abolishing the threat of nuclear war requires the outlawing of nuclear weapons and dismantling current nuclear weapon stockpiles, but also depends on eliminating access to fissile material (nuclear weapon fuel). The near-universal use of weapons-grade, highly enriched uranium (HEU) to produce radiopharmaceuticals is a significant proliferation hazard. Health professionals have a strategic opportunity and obligation to progress the elimination of medically-related commerce in HEU, closing one of the most vulnerable pathways to the much-feared 'terrorist bomb'. PMID:17987979

  10. Hydrothermal alteration and the chemistry of ore-forming fluids in an unconformity-type uranium deposit

    SciTech Connect

    Komninou, A.; Sverjensky, D.A.

    1995-07-01

    Compositions of hydrothermal chlorite and fine-grained white mica from the inner and outer alteration halos in the Koongarra U deposit were analyzed by electron microprobe and analytical electron microscopy. Analyses show that although chlorite and white mica compositions vary considerably outside the main ore zone, they are uniform inside the ore zone. Ore-zone chlorite has a ratio of Fe/(Fe + Mg) of 0.25 and low octahedral occupancy (average 5.5 per formula unit), which may represent a mixture of di- and trioctahedral chlorite. White mica has a typical K + Na atomic content of 0.85 per formula unit. These compositions were used to calculate the activity ratios a{sub Fe{sup +2}}/a{sub H{sup +}}{sup 2}, a{sub Mg{sup +2}}/a{sub H{sup +}}{sup 2}, a{sub K{sup +}}/a{sub H{sup +}}, and a{sub Na{sup +}}/a{sub H{sup +}} for the hydrothermal fluids associated with deposition of uraninite. Hydrothermal apatite analyses in conjunction with salinities suggested from fluid inclusion studies were used to calculate the pH of the fluids during the pre-ore alteration. The calculated pH values range from 4.8 to 6.0. Finally, the coexistence of chlorite with quartz and hematite was used to calculate oxygen fugacities. The calculated values are about 2 log units higher than for the hematite-magnetite buffer at 200{degrees}C. Consequently, the oxidation state of the fluid lay in the hematite field and U was probably transported as uranyl complexes.

  11. [Detection of trace uranium in air with field spectrometry].

    PubMed

    Yang, Ya-Xin; Xiao, Sai-Jin; Liu, Qing-Cheng; Huang, Long-Zhu; Peng, Dao-Feng; Zheng, Yong-Ming

    2012-07-01

    As a natural radioactive element, uranium and its compounds exist as aerosol and transfer in air. In gas phase, uranium can cause various kinds of radioactive damage to human body. The change in its concentration in a local area is related to the exploration and utilization of nuclear energy. Therefore, the development of field method for rapid uranium detection in air sample is very important. In this contribution, the air samples over uranium ores collected by a general pump was absorbed with 2.0 mol x L(-1) nitrate and then reacted with solid reagent kit. When the reaction between trace uranium and chromogenic reagent was finished, the homemade portable photometer was used to measure the absorbance. The results showed that the concentration of uranium in air samples over low grade uranium ores can be successfully determined by the present method and the values agree with that obtained by ICP-MS. The RSD measured by the new method was 1.72%. The application of the new field spectrometry in discriminating uranium ores from other ores has the potential advantages of easy operation, cost-saving and high accuracy. PMID:23016358

  12. Degradation problems with the solvent extraction organic at Roessing uranium

    SciTech Connect

    Munyungano, Brodrick; Feather, Angus; Virnig, Michael

    2008-07-01

    Roessing Uranium Ltd recovers uranium from a low-grade ore in Namibia. Uranium is recovered and purified from an ion-exchange eluate in a solvent-extraction plant. The solvent-extraction plant uses Alamine 336 as the extractant for uranium, with isodecanol used as a phase modifier in Sasol SSX 210, an aliphatic hydrocarbon diluent. Since the plant started in the mid 1970's, there have been a few episodes where the tertiary amine has been quickly and severely degraded when the plant was operated outside certain operating parameters. The Rossing experience is discussed in more detail in this paper. (authors)

  13. Why is weapons grade plutonium more hazardous to work with than highly enriched uranium?

    DOE PAGESBeta

    Cournoyer, Michael E.; Costigan, Stephen A.; Schake, Bradley S.

    2015-07-01

    Highly Enriched Uranium and Weapons grade plutonium have assumed positions of dominant importance among the actinide elements because of their successful uses as explosive ingredients in nuclear weapons and the place they hold as key materials in the development of industrial use of nuclear power. While most chemists are familiar with the practical interest concerning HEU and WG Pu, fewer know the subtleties among their hazards. In this study, a primer is provided regarding the hazards associated with working with HEU and WG Pu metals and oxides. The care that must be taken to safely handle these materials is emphasizedmore » and the extent of the hazards is described. The controls needed to work with HEU and WG Pu metals and oxides are differentiated. Given the choice, one would rather work with HEU metal and oxides than WG Pu metal and oxides.« less

  14. Why is weapons grade plutonium more hazardous to work with than highly enriched uranium?

    SciTech Connect

    Cournoyer, Michael E.; Costigan, Stephen A.; Schake, Bradley S.

    2015-08-01

    Highly Enriched Uranium and Weapons grade plutonium have assumed positions of dominant importance among the actinide elements because of their successful uses as explosive ingredients in nuclear weapons and the place they hold as key materials in the development of industrial use of nuclear power. While most chemists are familiar with the practical interest concerning HEU and WG Pu, fewer know the subtleties among their hazards. In this study, a primer is provided regarding the hazards associated with working with HEU and WG Pu metals and oxides. The care that must be taken to safely handle these materials is emphasized and the extent of the hazards is described. The controls needed to work with HEU and WG Pu metals and oxides are differentiated. Given the choice, one would rather work with HEU metal and oxides than WG Pu metal and oxides.

  15. Why is weapons grade plutonium more hazardous to work with than highly enriched uranium?

    SciTech Connect

    Cournoyer, Michael E.; Costigan, Stephen A.; Schake, Bradley S.

    2015-07-01

    Highly Enriched Uranium and Weapons grade plutonium have assumed positions of dominant importance among the actinide elements because of their successful uses as explosive ingredients in nuclear weapons and the place they hold as key materials in the development of industrial use of nuclear power. While most chemists are familiar with the practical interest concerning HEU and WG Pu, fewer know the subtleties among their hazards. In this study, a primer is provided regarding the hazards associated with working with HEU and WG Pu metals and oxides. The care that must be taken to safely handle these materials is emphasized and the extent of the hazards is described. The controls needed to work with HEU and WG Pu metals and oxides are differentiated. Given the choice, one would rather work with HEU metal and oxides than WG Pu metal and oxides.

  16. Radiogenic production of 10Be and 26Al in uranium and thorium ores: Implications for studying terrestrial samples containing low levels of 10Be and 26Al

    NASA Astrophysics Data System (ADS)

    Sharma, P.; Middleton, R.

    1989-03-01

    10Be and 26Al are produced by cosmic-ray-induced spallation of atmospheric constituents, and also as has recently been shown, by spallation in the rocks exposed to cosmic rays. We now present experimental data showing that these two isotopes can also be produced by radiation from uranium and thorium decay chain radionuclides contained within the host rocks. We have measured the 10Be and 26Al concentrations in a number of shielded uranium (spontaneous fission half-life ~10 26 years) and thorium (no spontaneous-fission-decay mode) ores using accelerator mass spectrometry. The concentrations of 10Be and 26Al range from 2.8·10 6 to 29.6·10 6 and 1.1 · 10 7 to 1.43· 10 atoms g -, respectively. The high concentrations of 10Be and 26Al imply unacceptably-high branching ratios (~ 10 -4 to 10 -1) for their production from spontaneous fission and coupled with the presence of 10Be and 26A1 in the Th ores, eliminate spontaneous fission as the major source of either isotope. The large 26A1 to 10Be ratio found in all the samples eliminates atmospheric production. The most likely sources are the alpha reactions, 7Li( α, p) 10Be and 23Na( α, n) 26Al, and neutron reactions, 9Be( n, γ) 10Be, 10B( n, p) 10Be and 13C( n, α) 10Be. Our work provides an upper limit on the contribution of in situ radioactivity to samples containing low levels of 10Be and 26Al. We have calculated the equilibrium concentrations of 10Be and 26Al in a wide variety of geologic materials including granites, ultramafic rocks, basalts, shales, pelagic sediments, ferromanganese nodules, tektites and Libyan Desert Glass. The calculated concentrations of 10Be and 26Al range from <1 to 4100 and 9 to 10.3 · 10 6 atoms g -1, respectively. Implications of these calculations are discussed. In general, the calculated amounts of radiogenically produced 10Be in geological materials are quite small and frequently negligible compared to cosmogenic production, while that of 26Al are significant and sometimes the

  17. 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

  18. Application of the angle measure technique as image texture analysis method for the identification of uranium ore concentrate samples: New perspective in nuclear forensics.

    PubMed

    Fongaro, Lorenzo; Ho, Doris Mer Lin; Kvaal, Knut; Mayer, Klaus; Rondinella, Vincenzo V

    2016-05-15

    The identification of interdicted nuclear or radioactive materials requires the application of dedicated techniques. In this work, a new approach for characterizing powder of uranium ore concentrates (UOCs) is presented. It is based on image texture analysis and multivariate data modelling. 26 different UOCs samples were evaluated applying the Angle Measure Technique (AMT) algorithm to extract textural features on samples images acquired at 250× and 1000× magnification by Scanning Electron Microscope (SEM). At both magnifications, this method proved effective to classify the different types of UOC powder based on the surface characteristics that depend on particle size, homogeneity, and graininess and are related to the composition and processes used in the production facilities. Using the outcome data from the application of the AMT algorithm, the total explained variance was higher than 90% with Principal Component Analysis (PCA), while partial least square discriminant analysis (PLS-DA) applied only on the 14 black colour UOCs powder samples, allowed their classification only on the basis of their surface texture features (sensitivity>0.6; specificity>0.6). This preliminary study shows that this method was able to distinguish samples with similar composition, but obtained from different facilities. The mean angle spectral data obtained by the image texture analysis using the AMT algorithm can be considered as a specific fingerprint or signature of UOCs and could be used for nuclear forensic investigation. PMID:26992543

  19. Temporal variability of radon in a remediated tailing of uranium ore processing--the case of Urgeiriça (central Portugal).

    PubMed

    Barbosa, S M; Lopes, F; Correia, A D; Barbosa, S; Pereira, A C; Neves, L F

    2015-04-01

    Radon monitoring at different levels of the cover of the Urgeiriça tailings shows that the sealing is effective and performing as desired in terms of containing the strongly radioactive waste resulting from uranium ore processing. However, the analysis of the time series of radon concentration shows a very complex temporal structure, particularly at depth, including very large and fast variations from a few tens of kBq m(-3) to more than a million kBq m(-3) in less than one day. The diurnal variability is strongly asymmetric, peaking at 18 h/19 h and decreasing very fast around 21 h/22 h. The analysis is performed for summer and for a period with no rain in order to avoid the potential influence of precipitation and related environmental conditions on the radon variability. Analysis of ancillary measurements of temperature, relative humidity, wind speed and wind direction, as well as atmospheric pressure reanalysis data shows that the daily averaged radon concentration in the taillings material is anti-correlated with the atmospheric pressure and that the diurnal amplitude is associated with the magnitude of atmospheric pressure daily oscillations. PMID:25618233

  20. Determination of uranium, iron, copper, and nickel from ore samples by MEKC using N,N'-ethylene bis(salicylaldimine) as complexing reagent.

    PubMed

    Mirza, Muhammed Aslam; Khuhawar, Muhammad Yar; Arain, Rafee

    2008-02-01

    An analytical procedure has been developed for the separation of dioxouranium(VI), iron(III), copper(II), nickel(II), cobalt(II), cobalt(III), palladium(II), and thorium(IV) by MEKC using N,N'-ethylene bis(salicylaldimine) (H(2)SA(2)en) as a complexing reagent with total runtime <4.5 min. SDS was used as micellar medium at pH 8 with sodium tetraborate buffer (0.1 M). An uncoated fused-silica capillary with an effective length of 50 cm x 75 microm id was used with an applied voltage of 30 kV with photodiode array detection at 231 nm. Linear calibrations were obtained within 0.111-1000 microg/mL of each element with LODs within 37-325 ng/mL. The developed method was tested for analysis of uranium ore samples indicating its presence within 103-1789 microg/g with RSD within 0.79-1.87%. Likewise copper, nickel, and iron in their combined matrix were also simultaneously determined with RSD 0.4-1.6% (n = 6). PMID:18186535

  1. Introduction to ore geology

    SciTech Connect

    Evans, A.M.

    1987-01-01

    This textbook on ore geology is for second and third year undergraduates and closely parallels the undergraduate course given in this subject at England's University of Leicester. The volume covers three major areas: (1) principles of ore geology, (2) examples of the most important types of ore deposits, and (3) mineralization in space and time. Many chapters have been thoroughly revised for this edition and a chapter on diamonds has been added. Chapters on greisen and pegmatite have also been added, the former in response to the changing situation in tin mining following the recent tin crisis, and the latter in response to suggestions from geologists in a number of overseas countries. Some chapters have been considerably expanded and new sections added, including disseminated gold deposits and unconformity-associated uranium deposits. The author also expands on the importance of viewing mineral deposits from an economic standpoint.

  2. Isotopic fractionation of uranium in sandstone

    USGS Publications Warehouse

    Rosholt, J.N.; Shields, W.R.; Garner, E.L.

    1963-01-01

    Relatively unoxidized black uranium ores from sandstone deposits in the western United States show deviations in the uranium-235 to uranium-234 ratio throughout a range from 40 percent excess uranium-234 to 40 percent deficient uranium-234 with respect to a reference uranium-235 to uranium-234 ratio. The deficient uranium-234 is leached preferentially to uranium-238 and the excess uranium-234 is believed to result from deposition of uranium-234 enriched in solutions from leached deposits.

  3. 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.

  4. Desilicification and iron activation-reprecipitation in the high-grade magnetite ores in BIFs of the Anshan-Benxi area, China: Evidence from geology, geochemistry and stable isotopic characteristics

    NASA Astrophysics Data System (ADS)

    Li, Hou-Min; Yang, Xiu-Qing; Li, Li-Xing; Zhang, Zhao-Chong; Liu, Ming-Jun; Yao, Tong; Chen, Jing

    2015-12-01

    The high-grade magnetite ores related to banded iron formations (BIFs) in the Anshan-Benxi area, Liaoning Province in China, have been widely interpreted as the product of replacement of protore by epigenetic hydrothermal fluids. The high-grade iron ore reserves in the mining area II (164 million tons) in the Gongchangling (G2) and Qidashan-Wangjiabuzi (QW) iron deposits (11.45 million tons) are the largest deposits in the Anshan-Benxi area. We present a detailed comparison of the geology, geochemical and stable isotopic compositions of the iron ores in the G2 with those in the QW to constrain the role of desilicification and iron activation-reprecipitation in converting the BIFs to high-grade magnetite ores. These two deposits show marked difference in wall-rock alteration, geochemical features, and oxygen and sulfur isotopic compositions. Wall-rock alteration in the G2 is characterized by garnetization, actinolitization, and chloritization, whereas the QW shows chloritization, biotitization and sericitization. The geochemistry of altered rocks in the G2 is characterized by slight REE fractionation, positive Eu and no significant Ce anomalies, whereas the QW is characterized by high ΣREE contents, strong REE fractionation, and the absence of significant Eu and Ce anomalies. High-grade iron ores in the G2 show similar δ18OV-SMOW values for magnetite, lower δ18OV-SMOW values for quartz and higher δ34SV-CDT values for pyrite when compared to the BIFs, whereas the QW shows lower δ18OV-SMOW values for magnetite, similar δ18OV-SMOW values for quartz and similar δ34SV-CDT values for pyrite. These features indicate that desilicification process by hypogene alkaline-rich hydrothermal fluids were possibly responsible for the formation of high-grade iron ores in the G2 whereas iron activation-reprecipitation process by migmatitic-hydrothermal fluids generated the high-grade iron orebodies in QW.

  5. Geologic controls of uranium mineralization in the Tallahassee Creek uranium district, Fremont County, Colorado.

    USGS Publications Warehouse

    Dickinson, K.A.

    1981-01-01

    Two important orebodies have been defined by drilling in the Tallahassee Creek uranium district, Fremont County, Colorado, namely the Hansen and the Picnic Tree. Host rocks are respectively the upper Eocene Echo park Alluvium, and the lower Oligocene Tallahassee Creek Conglomerate. Average ore grade is about 0.08% U3O8. The principal source rock is the lower Oligocene Wall Mountain Tuff. Leaching and transportation of the uranium occurred in alkaline oxidizing ground water that developed during alteration of the ash in a semi-arid environment. The uranium was transported in the groundwater and deposited in a reducing environment controlled by carbonaceous material and associated pyrite. Localization of the ore was controlled by groundwater flow conditions and by the distribution of organic matter in the host rock. -from Author

  6. Uranium content and leachable fraction of fluorspars.

    PubMed

    Landa, E R; Councell, T B

    2000-09-01

    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 microg kg(-1), with a mean of 2,145 microg kg(-1). As a point of comparison, the average concentration of uranium in the upper crust of the earth is about 2,500 microg 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. PMID:10949254

  7. Uranium*

    NASA Astrophysics Data System (ADS)

    Grenthe, Ingmar; Drożdżyński, Janusz; Fujino, Takeo; Buck, Edgar C.; Albrecht-Schmitt, Thomas E.; Wolf, Stephen F.

    Uranium compounds have been used as colorants since Roman times (Caley, 1948). Uranium was discovered as a chemical element in a pitchblende specimen by Martin Heinrich Klaproth, who published the results of his work in 1789. Pitchblende is an impure uranium oxide, consisting partly of the most reduced oxide uraninite (UO2) and partly of U3O8. Earlier mineralogists had considered this mineral to be a complex oxide of iron and tungsten or of iron and zinc, but Klaproth showed by dissolving it partially in strong acid that the solutions yielded precipitates that were different from those of known elements. Therefore he concluded that it contained a new element (Mellor, 1932); he named it after the planet Uranus, which had been discovered in 1781 by William Herschel, who named it after the ancient Greek deity of the Heavens.

  8. 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

    ... 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. Environmental control technology for mining and milling low-grade uranium resources

    SciTech Connect

    Weakley, S.A.; Blahnik, D.E.; Long, L.W.; Bloomster, C.H.

    1981-04-01

    This study examined the type and level of wastes that would be generated in the mining and milling of U/sub 3/O/sub 8/ from four potential domestic sources of uranium. The estimated costs of the technology to control these wastes to different degrees of stringency are presented.

  16. Geology and ore deposits of the Monument Valley area, Apache and Navajo counties, Arizona: Part II

    USGS Publications Warehouse

    Witkind, I.J.; Thaden, R.E.

    1958-01-01

    In 1951 and 1952, the U.S. Geological Survey conducted a program of uranium investigations and geologic mapping in the Monument Valley area, Apache and Navajo Counties, Ariz. About 700 square miles were mapped on the Navajo Indian Reservation. A resource appraisal of the area was an inherent part of the program, and is detailed in this report. Production of vanadium and uranium is from two areas, the Monument No. 1 mine area in Navajo County, and the Monument No. 2 mine area in Apache County. In the period 1942-53 about 200,300 tons of ore was produced from these two areas. This ore yielded about 1,700,000 pounds of U3O8 and about 6,500,000 pounds of V2O5. The grade ranged from 0.15 percent U3O8 to 0.60 percent U3O8, and from 0.38 percent V2O5 to 3.02 percent V2O5. The vanadium-uranium ratio is about 4:1. The ore deposits are composed principally of the hydrous calcium-uranium vanadate tyuyamunite in basal channel sediments of the Shinarump member off the Chinle formation. Four types of ore bodies are present: (1) rods, (2) tabular ore bodies, (3) corvusite-type ore bodies, and (4) rolls. The reserves of uranium- and vanadium-bearing material are classed as measured, indicated, inferred, and potential. The reserves are further divided into three grade classes for material 1 foot or more thick: (1) 0.10 percent U3O8 and 1.00 percent V2O5 and above; (2) 0.05 percent U3O8 and 0.50 percent V2O5 and less than 0.10 percent U3O8 and 1.00 percent V2O5; and (3) 0.01 percent U3O8 and 0.10 percent V2O5 and less than 0.05 percent U3O8 and 0.05 percent V2O5. Measured reserves as of June 1953, in the Monument Valley area, Arizona, (all in the Monument No. 2 mine) total about 36,000 tons. Indicated reserves in the first grade class amount to about 62,000 tons. In this same grade class inferred reserves total about 3,000,000 tons. In the second grade class indicated and inferred reserves amount to about 2,000,000 tons. Inferred reserves in the third grade class total about 345

  17. 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)

  18. Field evaluation of active and passive direct uranium borehole logging systems

    SciTech Connect

    Wilson, R.D.; Cosby, M.S.; Stone, J.M.

    1980-05-01

    Thirty test holes were placed in a variety of geologic environments and for wide variations in ore zone grade, thickness, and uranium/radium disequilibrium condition. The ore zones of each test hole were core drilled with >90% core recovery. Core samples were analyzed for a number of trace, minor and major elemental constituents, and for several physical properties. A standard suite of geophysical logs was obtained prior to casing the test holes. Direct uranium logs were then obtained by the PGT, Sandia, IRT, and Century Geophysical sondes. All core and logging results have been written to a computerized data base. The data base was then used to produce various comparison plots and other forms of data evaluation. Calculation of the grade-thickness product for each ore zone and sonde type shows that the logging results are widely dispersed about the values obtained from the core assays. Results for the IRT sonde are systematically lower than core results, the Century sonde severely overestimates the grade-thickness product for very low grade zones, and the PGT sonde exhibits a systematic trend toward underestimating grade-thickness for higher grade (>1000 ppM) ore zones. The Sandia sonde shows no such systematic trends and agrees well with core results at the higher grades (1000 to 2500 ppM range). Neglecting the very large discrepancies observed, for example, with Century's sonde at low grade, or with IRT's sonde when malfunction was suspected, the four direct uranium logging sondes exhibited similar dispersions about the core results.Approximately 50 percent of the time the logging sondes are within +-30% of the core results while about 75% of the time they are within +-50%. A certain amount of this dispersion is due to the unfavorable borehole conditions and to the variety of geologic environments sampled.

  19. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the 233U isotope in the VVER reactors using thorium and heavy water

    NASA Astrophysics Data System (ADS)

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium-uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D2O, H2O) is proposed. The method is characterized by efficient breeding of the 233U isotope and safe reactor operation and is comparatively simple to implement.

  20. 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.

  1. Weapons-grade plutonium dispositioning. Volume 3: A new reactor concept without uranium or thorium for burning weapons-grade plutonium

    SciTech Connect

    Ryskamp, J.M.; Schnitzler, B.G.; Fletcher, C.D.

    1993-06-01

    The National Academy of Sciences (NAS) requested that the Idaho National Engineering Laboratory (INEL) examine concepts that focus only on the destruction of 50,000 kg of weapons-grade plutonium. A concept has been developed by the INEL for a low-temperature, low-pressure, low-power density, low-coolant-flow-rate light water reactor that destroys plutonium quickly without using uranium or thorium. This concept is very safe and could be designed, constructed, and operated in a reasonable time frame. This concept does not produce electricity. Not considering other missions frees the design from the paradigms and constraints used by proponents of other dispositioning concepts. The plutonium destruction design goal is most easily achievable with a large, moderate power reactor that operates at a significantly lower thermal power density than is appropriate for reactors with multiple design goals. This volume presents the assumptions and requirements, a reactor concept overview, and a list of recommendations. The appendices contain detailed discussions on plutonium dispositioning, self-protection, fuel types, neutronics, thermal hydraulics, off-site radiation releases, and economics.

  2. 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.

  3. An evaporated seawater origin for the ore-forming brines in unconformity-related uranium deposits (Athabasca Basin, Canada): Cl/Br and δ 37Cl analysis of fluid inclusions

    NASA Astrophysics Data System (ADS)

    Richard, Antonin; Banks, David A.; Mercadier, Julien; Boiron, Marie-Christine; Cuney, Michel; Cathelineau, Michel

    2011-05-01

    Analyses of halogen concentration and stable chlorine isotope composition of fluid inclusions from hydrothermal quartz and carbonate veins spatially and temporally associated with giant unconformity-related uranium deposits from the Paleoproterozoic Athabasca Basin (Canada) were performed in order to determine the origin of chloride in the ore-forming brines. Microthermometric analyses show that samples contain variable amounts of a NaCl-rich brine (Cl concentration between 120,000 and 180,000 ppm) and a CaCl 2-rich brine (Cl concentration between 160,000 and 220,000 ppm). Molar Cl/Br ratios of fluid inclusion leachates range from ˜100 to ˜900, with most values between 150 and 350. Cl/Br ratios below 650 (seawater value) indicate that the high salinities were acquired by evaporation of seawater. Most δ 37Cl values are between -0.6‰ and 0‰ (seawater value) which is also compatible with a common evaporated seawater origin for both NaCl- and CaCl 2-rich brines. Slight discrepancies between the Cl concentration, Cl/Br, δ 37Cl data and seawater evaporation trends, indicate that the evaporated seawater underwent secondary minor modification of its composition by: (i) mixing with a minor amount of halite-dissolution brine or re-equilibration with halite during burial; (ii) dilution in a maximum of 30% of connate and/or formation waters during its migration towards the base of the Athabasca sandstones; (iii) leaching of chloride from biotites within basement rocks and (iv) water loss by hydration reactions in alteration haloes linked to uranium deposition. The chloride in uranium ore-forming brines of the Athabasca Basin has an unambiguous dominantly marine origin and has required large-scale seawater evaporation and evaporite deposition. Although the direct evidence for evaporative environments in the Athabasca Basin are lacking due to the erosion of ˜80% of the sedimentary pile, Cl/Br ratios and δ 37Cl values of brines have behaved conservatively at the basin

  4. A review of the environmental corrosion, fate and bioavailability of munitions grade depleted uranium.

    PubMed

    Handley-Sidhu, Stephanie; Keith-Roach, Miranda J; Lloyd, Jonathan R; Vaughan, David J

    2010-11-01

    Depleted uranium (DU) is a by-product of nuclear fuel enrichment and is used in antitank penetrators due to its high density, self-sharpening, and pyrophoric properties. Military activities have left a legacy of DU waste in terrestrial and marine environments, and there have been only limited attempts to clean up affected environments. Ten years ago, very little information was available on the dispersion of DU as penetrators hit their targets or the fate of DU penetrators left behind in environmental systems. However, the marked increase in research since then has improved our knowledge of the environmental impact of firing DU and the factors that control the corrosion of DU and its subsequent migration through the environment. In this paper, the literature is reviewed and consolidated to provide a detailed overview of the current understanding of the environmental behaviour of DU and to highlight areas that need further consideration. PMID:20858561

  5. Reference (Axially Graded) Low Enriched Uranium Fuel Design for the High Flux Isotope Reactor (HFIR)

    SciTech Connect

    Ilas, Germina; Primm, Trent

    2010-01-01

    During the past five years, staff at the Oak Ridge National Laboratory (ORNL) have studied the issue of whether the HFIR could be converted to low enriched uranium (LEU) fuel without degrading the performance of the reactor. Using state-of-the-art reactor physics methods and behind-the-state-of-the-art thermal hydraulics methods, the staff have developed fuel plate designs (HFIR uses two types of fuel plates) that are believed to meet physics and thermal hydraulic criteria provided the reactor power is increased from 85 to 100 MW. The paper will present a defense of the results by explaining the design and validation process. A discussion of the requirements for showing applicability of analyses to approval for loading the fuel to HFIR lead test core irradiation currently scheduled for 2016 will be provided. Finally, the potential benefits of upgrading thermal hydraulics methods will be discussed.

  6. National Uranium-Resource Evaluation: genesis of the Bokan Mountain, Alaska uranium-thorium deposits

    SciTech Connect

    Thompson, T.B.; Lyttle, T.; Pierson, J.R.

    1980-01-01

    The objective of this research project is to develop a model that can be used in evaluating peralkaline granitic-syenitic rocks for uranium potential. The deposits at Bokan Mountain (also known as Kendrick Bay) were studied to generate a specific model as to their mode of formation. To achieve the objective several types of data have been obtained: (1) Distinction by mapping and core logging of multiple intrusive phases within the Bokan Mountain Granite complex; (2) Detailed chemical and petrographic data on each igneous phase; (3) Extent of and mineralogical/chemical characteristics of the associated wallrock alteration; (4) Radiometric dates on magmatic and hydrothermal products; (5) Fluid inclusion analysis of quartz, calcite, and fluorite from mineralized rock; (6) Ore and sulfide mineralogy; (7) C, O, and S isotope analyses of minerals from mineralized rock; (8) Trace element dispersion with respect to mineralized zones; and (9) Structural data for interpretation of emplacement mechanisms as well as post-magmatic events important to ore localization. The U/Th mineralization is localized in shear zones as vein-like bodies or in irregular cylindrical bodies formed by concentrations of microfractures. The ore zones are localized within or on top of syenitic masses and have intense albitization and chloritization, with subordinate amounts of calcite, fluorite, quartz, sulfides, and tourmaline. Hematite occurs peripherally to the higher-grade ore zones. Uranothrorite and uraninite are the main ore minerals.

  7. 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.

  8. Reduction kinetics of aqueous U(VI) in acidic chloride brines to uraninite by methane, hydrogen or C-graphite under hydrothermal conditions: Implications for the genesis of unconformity-related uranium ore deposits

    NASA Astrophysics Data System (ADS)

    Dargent, Maxime; Truche, Laurent; Dubessy, Jean; Bessaque, Gilles; Marmier, Hervé

    2015-10-01

    The formation of hydrothermal uranium ore deposits involves the reduction of dissolved U(VI)(aq) to uraninite. However, the nature of the reducing agent and the kinetics of such a process are currently unknown. These questions are addressed through dedicated experiments performed under conditions relevant for the genesis of unconformity-related uranium (URU) deposits. We tested the efficiency of the following potential reductants supposed to be involved in the reaction: H2, CH4, C-graphite and dissolved Fe(II). Results demonstrate the great efficiency of H2, CH4 and C-graphite to reduce U(VI)(aq) into uraninite in acidic chloride brines, unlike dissolved Fe(II). Times needed for H2 (1.4 bar), CH4 (2.4 bar) and C-graphite (water/carbon mass ratio = 10) to reduce 1 mM of U(VI)(aq) in an acidic brine (1 m LiCl, pH ≈ 1 fixed by HCl) to uraninite at 200 °C are 12 h, 3 days and 4 months, respectively. The effects of temperature (T) between 100 °C and 200 °C, H2 partial pressure (0.14, 1.4, and 5.4 bar), salinity (0.1, 1 and 3.2 m LiCl) and pH at 25 °C (0.8 and 3.3) on the reduction rate were also investigated. Results show that increasing temperature and H2 partial pressure increase the reaction rate, whereas increasing salinity or pH have the reverse effect. The reduction of uranyl to uraninite follows an apparent zero-order with respect to time, whatever the considered electron donor. From the measured rate constants, the following values of activation energy (Ea), depending on the nature of the electron donor, have been derived: EaC-graphite = 155 ± 3 kJ mol-1, EaCH4 = 143 ± 6 kJ mol-1, and EaH2 = 124 ± 15 kJ mol-1 at T < 150 °C and 32 ± 6 kJ mol-1 at T > 150 °C. An empirical relationship between the reaction rate, the hydrogen partial pressure, the uranyl speciation, and the temperature is also proposed. This allows an estimation of the time of formation of a giant U ore deposit such as McArthur River (Canada). The duration of the mineralizing event is

  9. Appraisal of the accuracy of U.S. Geological Survey ore reserve estimates for uranium-vanadium deposits on the Colorado Plateau

    USGS Publications Warehouse

    Bush, Alfred Lerner; Stager, Harold Keith

    1954-01-01

    The U.S. Geological Survey has made estimates of the reserves of uranium and vanadium in the carnotite deposits explored by Geological Survey drilling on the Colorado Plateau. This report presents an appraisal of the accuracy of the reserve estimates for deposits in the Uravan mineral belt, the causes of inaccuracy, and the significance of the estimates in terms of the total known reserves of the region.

  10. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the {sup 233}U isotope in the VVER reactors using thorium and heavy water

    SciTech Connect

    Marshalkin, V. E. Povyshev, V. M.

    2015-12-15

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium–uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D{sub 2}O, H{sub 2}O) is proposed. The method is characterized by efficient breeding of the {sup 233}U isotope and safe reactor operation and is comparatively simple to implement.

  11. Uranium deposits in Grant County, New Mexico

    USGS Publications Warehouse

    Granger, Harry C.; Bauer, Herman L., Jr.; 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.

  12. Metals fact sheet - uranium

    SciTech Connect

    1996-04-01

    About 147 million pounds of this radioactive element are consumed annually by the worldwide nuclear power and weapons industries, as well as in the manufacture of ceramics and metal products. The heaviest naturally occurring element, uranium is typically found in intrusive granites, igneous and metamorphic veins, tabular sedimentary deposits, and unconformity-related structures. This article discusses the geology, exploitation, market, and applications of uranium and uranium ores.

  13. Tetravalent uranium in calcite.

    SciTech Connect

    Sturchio, N. C.; Antonio, M. R.; Soderholm, L.; Sutton, S. R.; Brannon, J. C.; Univ. of Chicago; Washington Univ.

    1998-08-14

    X-ray absorption spectroscopy and x-ray fluorescence microprobe studies of 35-million-year-old calcite from a Mississippi Valley-type zinc ore deposit indicate substitution of tetravalent uranium for divalent calcium. Thus, tetravalent uranium has a stable location in calcite deposited under reducing conditions. This result validates uranium-series dating methods (including uranium/lead dating) for ancient calcite and shows that calcite provides a sink for uranium in deep groundwater aquifers and anoxic lacustrine and marine basins.

  14. Tetravalent uranium in calcite

    PubMed

    Sturchio; Antonio; Soderholm; Sutton; Brannon

    1998-08-14

    X-ray absorption spectroscopy and x-ray fluorescence microprobe studies of 35-million-year-old calcite from a Mississippi Valley-type zinc ore deposit indicate substitution of tetravalent uranium for divalent calcium. Thus, tetravalent uranium has a stable location in calcite deposited under reducing conditions. This result validates uranium-series dating methods (including uranium/lead dating) for ancient calcite and shows that calcite provides a sink for uranium in deep groundwater aquifers and anoxic lacustrine and marine basins. PMID:9703507

  15. Uranium in Precambrian granitic rocks of the St. Francois Mountains, southeastern Missouri: with comments on uranium resource potential

    USGS Publications Warehouse

    Nash, J. Thomas

    1977-01-01

    Red granites of the St. Francois Mountains are highly radioactive and contain 4 to 34 parts per million (ppm) uranium. The most radioactive is the Graniteville Granite which contains an average of 16.9 ppm U and 42.6 ppm Th. The Butler Hill and Breadtray Granites also contain anomalous amounts, averaging 6.2 and 5.6 ppm U and 23.5 and 20.5 ppm Th respectively. Other Precambrian granitic rocks have normal concentrations of- U and Th. Fission track 'maps' indicate that high concentrations of uranium are associated with magnetite in the red granites; this uranium is presumed to be readily leachable by hydrothermal or supergene solutions. No uranium minerals or ore grade concentrations of uranium were observed in or near the granites, but there-are conceptual reasons for the possible existence of uranium deposits in intragranitic veins and onlapping Cambrian-Ordovician sedimentary rocks. Although the red granites constitute a good potential source of uranium, there is not much evidence for uranium having been mobilized. Identification of features such as lamprophyre dikes and 'episyenite' alteration, or sedimentary rocks containing reductants, would be of value for exploration and would permit more favorable resource appraisal.

  16. 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

  17. Method for locating and evaluating subsurface uranium deposits having an apparent grade of up to approximately 5% contained U/sub 3/O/sub 8/

    SciTech Connect

    Miller, B.R.

    1982-09-14

    This invention relates to a novel method for both locating and evaluating subsurface uranium-bearing formations containing an apparent grade of up to approximately 5% of contained U/sub 3/O/sub 8/. The steps include taking readings of the natural gamma count from an unknown radioactive formation on both the shielded and unshielded detectors with the external gamma source shielded, uncovering the external gamma source and reading the count-rate on both the shielded and unshielded detectors, comparing the ratio of the natural gamma count recorded by the unshielded and shielded detectors with a similar ratio recorded by the same detectors in a uranium-bearing matrix of known concentration no greater than approximately 5% in a state of equilibrium to ascertain first if a state of disequilibrium exists and, secondly , if a state of disequilibrium is found to exist then to determine if this state of apparent disequilibrium is being influenced by the presence of either thorium or potassium or, alternatively, is primarily the result of a disequilibrium between uranium and its daughter products. The natural radiation seen by the shielded probe provides the data for a determination of the apparent grade of U/sub 3/O/sub 8/ used in later calculations. Finally , if the disequilibrium is found to exist between uranium and its daughter products, then determining the direction and approximate order of magnitude of the disequilibrium by analyzing the ratio of the count rates detected by the shielded and unsheilded detectors ascertained from a suspected uranium-bearing formation.

  18. 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.

  19. Spectral discrimination of uranium-mineralized breccia pipes in northwestern Arizona

    SciTech Connect

    Kwarteng, A.Y.; Goodell, P.C.; Pingitore, N.E. Jr.; Wenich, K.J.

    1989-03-01

    The price of uranium is currently the lowest in more than a decade. The only type of uranium deposit that is economically viable in the depressed uranium market is such high-grade ore as the unconformity type found in Canada and Australia. Exploration for uranium-bearing breccia pipes in northwestern Arizona by both domestic and foreign companies is currently active because of the relatively high-grade ore they contain and their tendency to be polymetallic. In the US, uranium-mineralized breccia pipes are one of the few deposits that can compete in the current market. A stepwise discriminant analysis was performed on spectral data acquired from the field, laboratory, and Landsat thematic mapper (TM). The principal objectives were (1) to investigate the fundamental differences in the spectral properties of outcrops on the surface of breccia pipes and the background, (2) to choose TM bandpasses that were statistically optimum for distinguishing between breccia pipes and the background, and (3) to compare the results of the field, laboratory, and TM digital data which were acquired by different instruments having different spatial and spectral resolutions.

  20. Geologic controls of uranium mineralization in the Tallahassee Creek uranium district, Fremont County, Colorado

    SciTech Connect

    Dickinson, K.A.

    1981-10-01

    Two important orebodies have been defined by drilling in the Tallahassee Creek uranium district, Fremont County, Colorado. They are the Hansen orebody, which contains about 12 million kg of U/sub 3/O/sub 8/, and the Picnic Tree orebody, which contains about 1 million kg of U/sub 3/O/sub 8/. Host rock for the Hansen is the upper Eocene Echo Park Alluvium, and host rock for the Picnic Tree is the lower Oligocene Tallahassee Creek onglomerate. Average ore grade for both deposits is about 0.08 percent U/sub 3/O/sub 8/. The principal source rock for the uranium depsoits is the lower Oligocene Wall Mountain Tuff, although a younger volcanic rock, the Oligocene Thirtynine Mile Andesite, and Precambrian granitic rocks probably also contributed some uranium. Leaching and transportation of the uranium occurred in alkaline oxidizing ground water that developed during alteration of the ash in a semi-arid environment. The uranium was transported in the ground water to favorable sites where it was deposited in a reducing environment controlled by carbonaceous material and associated pyrite. Localization of the ore was controlled by ground-water flow conditions and by the distribution of organic matter in the host rock. Ground-water flow, which was apparently to the southeast in Echo Park Alluvium that is confined in the Echo Park graben, was impeded by a fault that offsets the southern end of the graben. This offset prevented efficient discharge into the ancestral Arkansas River drainage, and protected chemically reducing areas from destruction by the influx of large amounts of oxidizing ground water. The location of orebodies in the Echo Park Alluvium also may be related to areas where overlying rocks of low permeability were breached by erosion during deposition of the fluvial Tallahassee Creek Conglomerate allowing localized entry of uranium-bearing water.

  1. Uranium immobilization and nuclear waste

    SciTech Connect

    Duffy, C.J.; Ogard, A.E.

    1982-02-01

    Considerable information useful in nuclear waste storage can be gained by studying the conditions of uranium ore deposit formation. Further information can be gained by comparing the chemistry of uranium to nuclear fission products and other radionuclides of concern to nuclear waste disposal. Redox state appears to be the most important variable in controlling uranium solubility, especially at near neutral pH, which is characteristic of most ground water. This is probably also true of neptunium, plutonium, and technetium. Further, redox conditions that immobilize uranium should immobilize these elements. The mechanisms that have produced uranium ore bodies in the Earth's crust are somewhat less clear. At the temperatures of hydrothermal uranium deposits, equilibrium models are probably adequate, aqueous uranium (VI) being reduced and precipitated by interaction with ferrous-iron-bearing oxides and silicates. In lower temperature roll-type uranium deposits, overall equilibrium may not have been achieved. The involvement of sulfate-reducing bacteria in ore-body formation has been postulated, but is uncertain. Reduced sulfur species do, however, appear to be involved in much of the low temperature uranium precipitation. Assessment of the possibility of uranium transport in natural ground water is complicated because the system is generally not in overall equilibrium. For this reason, Eh measurements are of limited value. If a ground water is to be capable of reducing uranium, it must contain ions capable of reducing uranium both thermodynamically and kinetically. At present, the best candidates are reduced sulfur species.

  2. Radiological aspects of in situ uranium recovery

    SciTech Connect

    BROWN, STEVEN H.

    2007-07-01

    In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining / milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques, involving considerably less capital expenditure. Technologies such as Uranium in situ leaching in situ recovery (ISL / ISR), have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and may make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial size solution mining production facilities have operated in the US since 1975. Solution mining involves the pumping of groundwater, fortified with oxidizing and complexing agents into an ore body, solubilizing the uranium in situ, and then pumping the solutions to the surface where they are fed to a processing plant. Processing involves ion exchange and may also include precipitation, drying or calcining and packaging operations depending on facility specifics. This paper presents an overview of the ISR process and the health physics monitoring programs developed at a number of commercial scale ISL / ISR Uranium recovery and production facilities as a result of the radiological character of these processes. Although many radiological aspects of the process are similar to that of conventional mills, conventional-type tailings as such are not generated. However, liquid and solid byproduct materials may be generated and impounded. The quantity and radiological character of these by products are related to facility specifics. Some special monitoring considerations are presented which are required due to the manner in which Radon gas is evolved in

  3. Uranium series disequilibrium in a Holocene uranium deposit in northeastern Washington

    SciTech Connect

    Zielinski, R.A.; Bush, C.A.; Rosholt, J.N.

    1985-01-01

    A recently discovered ore-grade accumulation of uranium in post-glacial, organic-rich sediments provides an opportunity for studying the early association of uranium and organic matter in a natural setting. The uranium occurs in valley-fill sediments of peat, peaty clay, silt, and sand along the north fork of Flodelle Creek, Stevens County, Washington. Sixteen lithologically distinct intervals in a 290 cm core were measured by high-resolution gamma-ray spectrometry and by thin-source alpha spectrometry to determine the abundance and distribution of uranium series nuclides and the extent of secular equilibrium within the uranium decay series. Samples taken above the 6700 to 7000 year old Mazama Ash (0-127 cm depth) are clearly most deficient in daughters, but a simple increase of daughters relative to uranium as a function of depth was not observed, probably because chemically diverse daughters that are decay-generated in situ have differing mobilities, and because upwelling ground waters continuously add more uranium and minor amounts of daughters. Measured alpha activity ratios of /sup 234/U//sup 238/U (1.31-1.38) are analytically indistinguishable from those measured in coexisting waters, suggesting a rather constant isotopic composition of introduced uranium and little preferential recoil of /sup 234/U daughter from sediment surfaces. A consistent excess of /sup 210/Pb relative to /sup 226/Ra is observed throughout the core, suggesting ground-water input of the highly mobile intervening daughter, /sup 222/Rn. The abundance of uranium (160-3300 ppm) correlates highly with the abundance of organic matter (3-60 wt.%) as do abundances of /sup 226/Ra, /sup 230/Th, and /sup 210/Pb below 127 cm depth.

  4. 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.

  5. The sources of our iron ores. II

    USGS Publications Warehouse

    Burchard, E.F.

    1933-01-01

    In this instalment** the iron ore deposits of the Lake Superior States, which normally furnish about 80 per cent, of the annual output of the United States, are described together with historical notes on discovery and transportation of ore. Deposits in the Mississippi Valley and Western States are likewise outlined and the sources of imported ore are given. Reviewing the whole field, it is indicated that the great producing deposits of the Lake Superior and southern Appalachian regions are of hematite in basin areas of sedimentary rocks, that hydrated iron oxides and iron carbonates are generally found in undisturbed comparatively recent sediments, and that magnetite occurs in metamorphic and igneous rocks; also that numerical abundance of deposits is not a criterion as to their real importance as a source of supply. Statistics of production of iron ore and estimates of reserves of present grade conclude the paper.

  6. 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.

  7. Fuel Grading Study on a Low-Enriched Uranium Fuel Design for the High Flux Isotope Reactor

    SciTech Connect

    Ilas, Germina; Primm, Trent

    2009-11-01

    An engineering design study that would enable the conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium to low-enriched uranium fuel is ongoing at Oak Ridge National Laboratory. The computational models used to search for a low-enriched uranium (LEU) fuel design that would meet the requirements for the conversion study, and the recent results obtained with these models during FY 2009, are documented and discussed in this report. Estimates of relevant reactor performance parameters for the LEU fuel core are presented and compared with the corresponding data for the currently operating high-enriched uranium fuel core. These studies indicate that the LEU fuel design would maintain the current performance of the HFIR with respect to the neutron flux to the central target region, reflector, and beam tube locations.

  8. Oxidized and reduced mineral assemblages in greenstone belt rocks of the St. Ives gold camp, Western Australia: vectors to high-grade ore bodies in Archaean gold deposits?

    NASA Astrophysics Data System (ADS)

    Neumayr, Peter; Walshe, John; Hagemann, Steffen; Petersen, Klaus; Roache, Anthony; Frikken, Peter; Horn, Leo; Halley, Scott

    2008-03-01

    Hydrothermal sulfide-oxide-gold mineral assemblages in gold deposits in the Archaean St. Ives gold camp in Western Australia indicate extremely variable redox conditions during hydrothermal alteration and gold mineralization in space and time. Reduced alteration assemblages (pyrrhotite-pyrite) occur in deposits in the southwest of the camp (e.g., Argo, Junction deposits) and moderately to strongly oxidized assemblages (magnetite-pyrite, hematite-pyrite) occur in deposits in the Central Corridor in the northeast (e.g., North Orchin, Revenge deposits). Reduced mineral assemblages flank the Central Corridor of oxidized deposits and, locally, cut across it along E-W trending faults. Oxidized mineral assemblages in the Central Corridor are focused on gravity lows which are interpreted to reflect abundant felsic porphyritic intrusions at about 1,000 m below present surface. Hydrothermal magnetite predates and is synchronous with early phases of gold-associated albite-carbonate-pyrite-biotite-chlorite hydrothermal alteration. Later-stage, gold-associated pyrite is in equilibrium with hematite. The spatial distribution and temporal sequence of iron sulfides and oxides with gold indicate the presence of at least two spatially restricted but broadly synchronous hydrothermal fluids with contrasting redox states. Sulfur isotope constraints support the argument that the different mineral assemblages reflect differences in redox conditions. The δ 34S values for pyrite for the St. Ives gold camp range between -8.4‰ and +5.1‰ with the negative values occurring in oxidized magnetite-rich domains and slightly negative or positive values occurring in reduced, pyrrhotitic domains. Preliminary spatial and paragenetic analysis of the distribution of iron sulfides and oxides in the St. Ives camp suggests that gold grades are highest where the redox state of the hydrothermal alteration assemblages switches from relatively reduced pyrrhotite-pyrite to relatively oxidized magnetite

  9. Gold remobilisation and formation of high grade ore shoots driven by dissolution-reprecipitation replacement and Ni substitution into auriferous arsenopyrite

    NASA Astrophysics Data System (ADS)

    Fougerouse, Denis; Micklethwaite, Steven; Tomkins, Andrew G.; Mei, Yuan; Kilburn, Matt; Guagliardo, Paul; Fisher, Louise A.; Halfpenny, Angela; Gee, Mary; Paterson, David; Howard, Daryl L.

    2016-04-01

    Both gold-rich sulphides and ultra-high grade native gold oreshoots are common but poorly understood phenomenon in orogenic-type mineral systems, partly because fluids in these systems are considered to have relatively low gold solubilities and are unlikely to generate high gold concentrations. The world-class Obuasi gold deposit, Ghana, has gold-rich arsenopyrite spatially associated with quartz veins, which have extremely high, localised concentrations of native gold, contained in microcrack networks within the quartz veins where they are folded. Here, we examine selected samples from Obuasi using a novel combination of quantitative electron backscatter diffraction analysis, ion microprobe imaging, synchrotron XFM mapping and geochemical modelling to investigate the origin of the unusually high gold concentrations. The auriferous arsenopyrites are shown to have undergone partial replacement (∼15%) by Au-poor, nickeliferous arsenopyrite, during localised crystal-plastic deformation, intragranular microfracture and metamorphism (340-460 °C, 2 kbars). Our results show the dominant replacement mechanism was pseudomorphic dissolution-reprecipitation, driven by small volumes of an infiltrating fluid that had relatively low ƒS2 and carried aqueous NiCl2. We find that arsenopyrite replacement produced strong chemical gradients at crystal-fluid interfaces due to an increase in ƒS2 during reaction, which enabled efficient removal of gold to the fluid phase and development of anomalously gold-rich fluid (potentially 10 ppm or more depending on sulphur concentration). This process was facilitated by precipitation of ankerite, which removed CO2 from the fluid, increasing the relative proportion of sulphur for gold complexation and inhibited additional quartz precipitation. Gold re-precipitation occurred over distances of 10 μm to several tens of metres and was likely a result of sulphur activity reduction through precipitation of pyrite and other sulphides. We suggest

  10. Uranium occurrence in major rock types by fission-track mapping

    SciTech Connect

    Ledger, E.G.; Bomber, B.J.; Schaftenaar, W.E.; Tieh, T.T.

    1984-04-01

    Microscopic occurrence of uranium has been determined in about 50 igneous rocks from various location, and in a genetically unrelated sandstone from south Texas. Precambrian granites from the Llano uplift of central Texas contain from a few ppm uranium (considered normal) to over 100 ppm on a whole-rock basis. In granite, uranium is concentrated in: (1) accessory minerals including zircon, biotite, allanite, Fe-Ti oxides, and altered sphene, (2) along grain boundaries and in microfractures by precipitation from deuteric fluids, and (3) as point sources (small inclusions) in quartz and feldspars. Tertiary volcanic rocks from the Davis Mountains of west Texas include diverse rock types from basalt to rhyolite. Average uranium contents increase from 1 ppm in basalts to 7 ppm in rhyolites. Concentration occurs: (1) in iron-titanium-oxides, zircon, and rutile, (2) in the fine-grained groundmass as uniform and point-source concentrations, and (3) as late uranium in cavities associated with banded, silica-rich material. Uranium in ore-grade sandstone is concentrated to more than 3%. Specific occurrences include (1) leucoxene and/or anatase, (2) opaline and calcite cements, (3) mud clasts and altered volcanic rock fragments, and (4) in a few samples, as silt-size uranium- and molybdenum-rich spheres. Uranium content is quite low in pyrite, marcasite, and zeolites.

  11. URANIUM SOLVENT EXTRACTION PROCESS

    DOEpatents

    Harrington, C.D.

    1959-09-01

    A method is given for extracting uranium values from ores of high phosphate content consisting of dissolving them in aqueous nitric acid, adjusting the concentration of the aqueous solution to about 2 M with respect to nitric acid, and then contacting it with diethyl ether which has previously been made 1 M with respect to nitric acid.

  12. Results of U.S. Geological Survey exploration for uranium-vanadium deposits in the Club Mesa area, Uravan district, Montrose County, Colorado

    USGS Publications Warehouse

    Boardman, Robert L.; Litsey, Linus R.; Bowers, Howard E.

    1957-01-01

    Between 1948 and 1953, the U. S. Geological Survey conducted diamond-drill exploration in the Club Mesa. area in the western part of the Uravan district, Montrose County, Colo. This drilling, consisting of 662 holes totaling 170,095 feet, was done to find minable uranium-vanadium deposits and to appraise uranium-vanadium reserves of the Club Mesa area. Rocks exposed in the area are gently dipping sedimentary formations of Mesozoic age. Sandstone units in the upper part of the Salt Wash member of the Morrison formation of Jurassic age contain most of the known uranium-vanadium deposits in the area; all of the large deposits are in the uppermost sandstone unit of that member. Of the 195 holes that penetrated mineralized rock, 74 holes penetrated ore layers, and 37 penetrated mineralized layers of ore grade but less than 1 foot thick. All of the ore layers and ore-grade layers are in sandstone units in the upper part of the Salt Wash member. The ore layers are in the bottom half of the host sandstone unit in about 90 percent of the holes in ore and in the bottom quarter of the unit in over 60 percent of these holes. Indicated and inferred reserves of ore discovered by the drilling total about 200,000 short tons averaging about 0.35 percent U308 and 1.80 percent V205. About 80 percent of the estimated reserves were included in six mining leases granted by the U. S. Atomic Energy Commission on deposits discovered by the drilling. Nearly all of the ore layers and most of the mineralized layers penetrated, are in sandstone units 30 feet or more thick that are in contact with at least 6 inches of green or gray mudstone. If these minimum thicknesses are used as cutoffs to determine ground favorable for ore, about 10 percent of the Club Mesa area explored by the U.S. Geological Survey can be classified as favorable and contains nearly all of the ore reserves discovered.

  13. Isolation and analyses of uranium tolerant Serratia marcescens strains and their utilization for aerobic uranium U(VI) bioadsorption.

    PubMed

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

    2011-08-01

    Enrichment-based methods targeted at uranium-tolerant populations among the culturable, aerobic, chemo-heterotrophic bacteria from the subsurface soils of Domiasiat (India's largest sandstone-type uranium deposits, containing an average ore grade of 0.1 % U(3)O(8)), indicated a wide occurrence of Serratia marcescens. Five representative S. marcescens isolates were characterized by a polyphasic taxonomic approach. The phylogenetic analyses of 16S rRNA gene sequences showed their relatedness to S. marcescens ATCC 13880 (≥99.4% similarity). Biochemical characteristics and random amplified polymorphic DNA profiles revealed significant differences among the representative isolates and the type strain as well. The minimum inhibitory concentration for uranium U(VI) exhibited by these natural isolates was found to range from 3.5-4.0 mM. On evaluation for their uranyl adsorption properties, it was found that all these isolates were able to remove nearly 90-92% (21-22 mg/L) and 60-70% (285-335 mg/L) of U(VI) on being challenged with 100 μM (23.8 mg/L) and 2 mM (476 mg/L) uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure. his capacity was retained by the isolates even after 24 h of incubation. Viability tests confirmed the tolerance of these isolates to toxic concentrations of soluble uranium U(VI) at pH 3.5. This is among the first studies to report uranium-tolerant aerobic chemoheterotrophs obtained from the pristine uranium ore-bearing site of Domiasiat. PMID:21887639

  14. Low-Enriched Uranium Fuel Design with Two-Dimensional Grading for the High Flux Isotope Reactor

    SciTech Connect

    Ilas, Germina; Primm, Trent

    2011-05-01

    An engineering design study of the conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel is ongoing at Oak Ridge National Laboratory. The computational models developed during fiscal year 2010 to search for an LEU fuel design that would meet the requirements for the conversion and the results obtained with these models are documented and discussed in this report. Estimates of relevant reactor performance parameters for the LEU fuel core are presented and compared with the corresponding data for the currently operating HEU fuel core. The results obtained indicate that the LEU fuel design would maintain the current performance of the HFIR with respect to the neutron flux to the central target region, reflector, and beam tube locations under the assumption that the operating power for the reactor fueled with LEU can be increased from the current value of 85 MW to 100 MW.

  15. URANIUM EXTRACTION

    DOEpatents

    Harrington, C.D.; Opie, J.V.

    1958-07-01

    The recovery of uranium values from uranium ore such as pitchblende is described. The ore is first dissolved in nitric acid, and a water soluble nitrate is added as a salting out agent. The resulting feed solution is then contacted with diethyl ether, whereby the bulk of the uranyl nitrate and a portion of the impurities are taken up by the ether. This acid ether extract is then separated from the aqueous raffinate, and contacted with water causing back extractioa of the uranyl nitrate and impurities into the water to form a crude liquor. After separation from the ether extract, this crude liquor is heated to about 118 deg C to obtain molten uranyl nitrate hexahydratc. After being slightly cooled the uranyl nitrate hexahydrate is contacted with acid free diethyl ether whereby the bulk of the uranyl nitrate is dissolved into the ethcr to form a neutral ether solution while most of the impurities remain in the aqueous waste. After separation from the aqueous waste, the resultant ether solution is washed with about l0% of its volume of water to free it of any dissolved impurities and is then contacted with at least one half its volume of water whereby the uranyl nitrate is extracted into the water to form an aqueous product solution.

  16. Sedimentary exhalative nickel-molybdenum ores in south China

    USGS Publications Warehouse

    Lott, D.A.; Coveney, R.M., Jr.; 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.

  17. Analysis of borehole geophysical information across a uranium deposit in the Jackson Group, Karnes County, Texas

    USGS Publications Warehouse

    Daniels, Jeffrey J.; Scott, James Henry; Smith, Bruce D.

    1979-01-01

    Borehole geophysical studies across a uranium deposit in the Jackson Group, South Texas, show the three geochemical environments often associated with uranium roll-type deposits: an altered (oxidized) zone, an ore zone, and an unaltered (reduced) zone. Mineralogic analysis of the total sulfides contained in the drill core shows only slight changes in the total sulfide content among the three geochemical regimes. However, induced polarization measurements on the core samples indicate that samples obtained from the reduced side of the ore zone are more electrically polarizable than those from the oxidized side of the ore zone, and therefore probably contain more pyrite. Analysis of the clay-size fraction in core samples indicates that montmorillonite is the dominant clay mineral. High resistivity values within the ore zone indicate the presence of calcite cement concentrations that are higher than those seen outside of the ore zone. Between-hole resistivity and induced polarization measurements show the presence of an extensive zone of calcite cement within the ore zone, and electrical polarizable material (such as pyrite) within and on the reduced side of the ore zone. A quantitative analysis of the between-hole resistivity data, using a layered-earth model, and a qualitative analysis of the between-hole induced polarization measurements showed that mineralogic variations among the three geochemical environments were more pronounced than were indicated by the geophysical and geologic well logs. Uranium exploration in the South Texas Coastal Plain area has focused chiefly in three geologic units: the Oakville Sandstone, the Catahoula Tuff, and the Jackson Group. The Oakville Sandstone and the Catahoula Tuff are of Miocene age, and the Jackson Group is of Eocene age (Eargle and others, 1971). Most of the uranium mineralization in these formations is low grade (often less than 0.02 percent U3O8) and occurs in shallow deposits that are found by concentrated exploratory

  18. Geology of dolomite-hosted uranium deposits at the Pitch Mine, Saguache County, Colorado

    SciTech Connect

    Nash, J.T.

    1981-01-01

    Newly documented uranium ore in the Pitch mine occurs chiefly in brecciated Mississippian Leadville Dolomite along the Chester upthrust zone, and to a lesser extent in sandstone, siltstone, and carbonaceous shale of the Pennsylvanian Belden Formation and in Precambrian granitic rocks and schist. Uranium-mineralized zones are generally thicker, more consistent, and of higher grade in dolomite than in other hosts, and roughly 50 percent of the new reserves are in dolomite. Strong physical control by dolomite is evident, as this is the only rock type that is pervasively brecciated within the fault slices that make up the footwall of the reverse-fault zone. Other rocks tended to either remain unbroken or undergo ductile deformation. Chemical controls on uranium deposition are subtle and appear chiefly to involve coprecipitation of FeS/sub 2/ as pyrite and marcasite, suggesting that sulfide ion may be the reductant. (JMT)

  19. GEOLOGY AND ORIGIN OF THE DEATH VALLEY URANIUM DEPOSIT, SEWARD PENINSULA, ALASKA.

    USGS Publications Warehouse

    Dickinson, Kendell A.; Cunningham, Kenneth D.; Ager, Thomas A.

    1987-01-01

    A uranium deposit discovered in 1977 in western Alaska, by means of airborne radiometric data, is the largest known in Alaska on the basis of industry reserve estimates. The deposit is apparently of epigenetic and supergene origin. The uranium was derived from the Cretaceous granite of the Darby pluton that forms part of the western side of Death Valley. Uranium from primary mineralization is in the subsurface in a marginal facies of the Tertiary sedimentary basin where nearshore coarse clastic rocks are interbedded with coal and lacustrine clay. The supergene enrichment is related to a soil horizon at the present ground surface. Extensive exploratory drilling took place from 1979 to 1981. The average grade of the potential ore is 0. 27 percent U//3O//8 and the average thickness is 3 m. The calculated reserves are 1,000,000 lbs U//3O//8; additional drilling would probably add to this figure. Additional study results are discussed.

  20. Origin of sedimentary humic acids, potential carriers of ore-forming elements

    NASA Astrophysics Data System (ADS)

    Hatcher, P. G.

    Humic acids are complex, macromolecular organic components of sediments and are defined by their solubility in dilute alkali insolubility in dilute acid. Because of their general structural characteristics (for example, their high proportion of oxygen functional groups), humic acids can complex with inorganic cations and may be important in forming ore deposits. In some instances (such as uranium ores), ore bodies are believed to have originated by mobilization of an ore-forming element complexed with humic acids and subsequent precipitation. Knowledge of the mechanism for the formation of humic acids is being applied to two major ore deposits. Carlin-type gold ores from Nevada show that humic acids may have been precursors. This suggests that the humic acids could have played a major role in the transport and accumulation of the ore.

  1. Magmatogenic manganese ores of the South Minusa Intermontane Trough

    NASA Astrophysics Data System (ADS)

    Kassandrov, E. G.; Mazurov, M. P.

    2009-10-01

    The first data on the mineral composition and formation conditions of manganese ore at the Chapsordag and Malosyrsky deposits in the Askiz ore district of Khakassia are integrated and systematized. The detailed mineralogical mapping of the deposits has been carried out. The identification of minerals and examination of the ore microstructure were performed with optical microscopy in transmitted and reflected light and using SEM/EDS, EMPA, XRD, IRS, and other methods. It was established that the ore mineralization is spatially and genetically related to the Early Devonian magmatism and accompanying hydrothermal activity and metasomatism. Syngenetic braunite was detected for the first time in elevated amounts reaching an economic level in the devitrified groundmass of volcanic rocks, in cement of lava breccia, and in fragments in pyroclastic rocks. By analogy with iron deposits, this magmatogenic type of manganese mineralization is regarded as ore lavas and tuffs combined with metasomatic and hydrothermal mineral assemblages into a strata-bound orebearing complex and as a source of hydrothermal metasomatic ore. The elevated Mn content in magmatic melts of the Early Devonian trachybasalt-trachyandesite-trachydacite association is caused by assimilation of Riphean and Lower Cambrian high-Mn carbonate sequences in crustal magma chambers. In contours of economic orebodies, the hydrothermal economic ore is recognized as sites of massive, patchy and impregnated, brecciated, stringer-disseminated, and disseminated varieties. High-grade massive ore occurs as stratiform and branching bodies up to 1.5 m thick and a few tens of meters long and as smaller pocketlike bodies. Braunite and pyrolusite (polianite) are major ore minerals varying in size, degree of crystallinity, and character of intergrowths with associating minerals. Gangue minerals include carbonates, sulfates, albite, quartz, chlorite, actinolite, piemontite, and okhotskite, a Mn-pumpellyite identified in Russia

  2. 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. PMID:24682031

  3. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    DOEpatents

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  4. 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. PMID:18505007

  5. The Complete Burning of Weapons Grade Plutonium and Highly Enriched Uranium with (Laser Inertial Fusion-Fission Energy) LIFE Engine

    SciTech Connect

    Farmer, J C; Diaz de la Rubia, T; Moses, E

    2008-12-23

    The National Ignition Facility (NIF) project, a laser-based Inertial Confinement Fusion (ICF) experiment designed to achieve thermonuclear fusion ignition and burn in the laboratory, is under construction at the Lawrence Livermore National Laboratory (LLNL) and will be completed in April of 2009. Experiments designed to accomplish the NIF's goal will commence in late FY2010 utilizing laser energies of 1 to 1.3 MJ. Fusion yields of the order of 10 to 20 MJ are expected soon thereafter. Laser initiated fusion-fission (LIFE) engines have now been designed to produce nuclear power from natural or depleted uranium without isotopic enrichment, and from spent nuclear fuel from light water reactors without chemical separation into weapons-attractive actinide streams. A point-source of high-energy neutrons produced by laser-generated, thermonuclear fusion within a target is used to achieve ultra-deep burn-up of the fertile or fissile fuel in a sub-critical fission blanket. Fertile fuels including depleted uranium (DU), natural uranium (NatU), spent nuclear fuel (SNF), and thorium (Th) can be used. Fissile fuels such as low-enrichment uranium (LEU), excess weapons plutonium (WG-Pu), and excess highly-enriched uranium (HEU) may be used as well. Based upon preliminary analyses, it is believed that LIFE could help meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the nation's and world's stockpile of spent nuclear fuel and excess weapons materials. LIFE takes advantage of the significant advances in laser-based inertial confinement fusion that are taking place at the NIF at LLNL where it is expected that thermonuclear ignition will be achieved in the 2010-2011 timeframe. Starting from as little as 300 to 500 MW of fusion power, a single LIFE engine will be able to generate 2000 to 3000 MWt in steady state for periods of years to decades, depending on the nuclear fuel and engine configuration. Because the fission blanket in a fusion

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. Bioprocessing of ores: Application to space resources

    NASA Technical Reports Server (NTRS)

    Johansson, Karl R.

    1992-01-01

    The role of microorganisms in the oxidation and leaching of various ores (especially those of copper, iron, and uranium) is well known. This role is increasingly being applied by the mining, metallurgy, and sewage industries in the bioconcentration of metal ions from natural receiving waters and from waste waters. It is concluded that bioprocessing using bacteria in closed reactors may be a variable option for the recovery of metals from the lunar regolith. Obviously, considerable research must be done to define the process, specify the appropriate bacteria, determine the necessary conditions and limitations, and evaluate the overall feasibility.

  11. ENVIRONMENTAL OVERVIEW OF UNCONVENTIONAL EXTRACTION OF URANIUM

    EPA Science Inventory

    Uranium mining areas in the United States are identified and briefly described, and the geologic, geochemical, and hydrologic factors associated with the various types of ore deposits are discussed. Uranium deposits that are now being mined or have recently been mined by solution...

  12. Relationship between collapse history and ore distribution in Sage Breccia pipe, northwestern Arizona

    SciTech Connect

    Brown, N.A.; Mead, R.H.; McMurray, J.M. )

    1989-09-01

    The Sage pipe is similar to other collapse breccia pipes in northern Arizona which have their beginnings in cave systems in the Redwall Limestone. Stoping of successively younger units caused the upward propagation of the pipe and provided the pipe-filling breccia. The Sage pipe extends at least 2,500 ft (762 m) vertically; the horizontal dimensions range from 100 to 300 ft (30.5-91 m), depending on variations in the adjoining host stratigraphy. The composition and distribution of breccia facies suggest a complex collapse history and variability in the mechanics of collapse. Rock failure took place both by block stoping and by decementation of sandstone and siltstone followed by flow of unconsolidated grains. The resulting breccias range from matrix to fragment-dominated, to sand flow breccia resulting from flow of individual grains. Episodic secondary collapse or readjustment within the breccia pile complicated facies distribution. Paragenetic studies indicate multiple periods of mineralization at Sage resulting in enrichment in an extensive suite of elements. Ore-grade uranium mineralization extends vertically for nearly 700 ft (213 m). Lateral distribution of the ore is variable and is directly related to breccia facies distribution. In generally, the more permeable breccias tend to be the most highly mineralized. Fracture, intergranular, and interfragment permeability were important to mineral distribution. Breccia continuity or plumbing was also important to lateral and vertical mineral distribution.

  13. 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

  14. 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.

  15. 38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE GEORGE M. CARL.' VIEW LOOKING EAST. (Also see OH-18-14, OH-18-39, and OH-18-40) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  16. 14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE 'GEORGE M. CAR.' VIEW LOOKING EAST. (Also see OH-18-38, OH-18-39, and OH-18-40.) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  17. Bog Manganese Ore: A Resource for High Manganese Steel Making

    NASA Astrophysics Data System (ADS)

    Pani, Swatirupa; Singh, Saroj K.; Mohapatra, Birendra K.

    2016-05-01

    Bog manganese ore, associated with the banded iron formation of the Iron Ore Group (IOG), occurs in large volume in northern Odisha, India. The ore is powdery, fine-grained and soft in nature with varying specific gravity (2.8-3.9 g/cm3) and high thermo-gravimetric loss, It consists of manganese (δ-MnO2, manganite, cryptomelane/romanechite with minor pyrolusite) and iron (goethite/limonite and hematite) minerals with sub-ordinate kaolinite and quartz. It shows oolitic/pisolitic to globular morphology nucleating small detritus of quartz, pyrolusite/romanechite and hematite. The ore contains around 23% Mn and 28% Fe with around 7% of combined alumina and silica. Such Mn ore has not found any use because of its sub-grade nature and high iron content, and is hence considered as waste. The ore does not respond to any physical beneficiation techniques because of the combined state of the manganese and iron phases. Attempts have been made to recover manganese and iron value from such ore through smelting. A sample along with an appropriate charge mix when processed through a plasma reactor, produced high-manganese steel alloy having 25% Mn within a very short time (<10 min). Minor Mn content from the slag was recovered through acid leaching. The aim of this study has been to recover a value-added product from the waste.

  18. Bog Manganese Ore: A Resource for High Manganese Steel Making

    NASA Astrophysics Data System (ADS)

    Pani, Swatirupa; Singh, Saroj K.; Mohapatra, Birendra K.

    2016-06-01

    Bog manganese ore, associated with the banded iron formation of the Iron Ore Group (IOG), occurs in large volume in northern Odisha, India. The ore is powdery, fine-grained and soft in nature with varying specific gravity (2.8-3.9 g/cm3) and high thermo-gravimetric loss, It consists of manganese (δ-MnO2, manganite, cryptomelane/romanechite with minor pyrolusite) and iron (goethite/limonite and hematite) minerals with sub-ordinate kaolinite and quartz. It shows oolitic/pisolitic to globular morphology nucleating small detritus of quartz, pyrolusite/romanechite and hematite. The ore contains around 23% Mn and 28% Fe with around 7% of combined alumina and silica. Such Mn ore has not found any use because of its sub-grade nature and high iron content, and is hence considered as waste. The ore does not respond to any physical beneficiation techniques because of the combined state of the manganese and iron phases. Attempts have been made to recover manganese and iron value from such ore through smelting. A sample along with an appropriate charge mix when processed through a plasma reactor, produced high-manganese steel alloy having 25% Mn within a very short time (<10 min). Minor Mn content from the slag was recovered through acid leaching. The aim of this study has been to recover a value-added product from the waste.

  19. Uranium industry annual 1993

    SciTech Connect

    Not Available

    1994-09-01

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U{sub 3}O{sub 8} (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U{sub 3}O{sub 8} (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world`s largest producer in 1993 with an output of 23.9 million pounds U{sub 3}O{sub 8} (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market.

  20. The Rožná uranium deposit (Bohemian Massif, Czech Republic): shear zone-hosted, late Variscan and post-Variscan hydrothermal mineralization

    NASA Astrophysics Data System (ADS)

    Kříbek, Bohdan; Žák, Karel; Dobeš, Petr; Leichmann, Jaromír; Pudilová, Marta; René, Miloš; Scharm, Bohdan; Scharmová, Marta; Hájek, Antonín; Holeczy, Daniel; Hein, Ulrich F.; Lehmann, Bernd

    2009-01-01

    Three major mineralization events are recorded at the Rožná uranium deposit (total mine production of 23,000 t U, average grade of 0.24% U): (1) pre-uranium quartz-sulfide and carbonate-sulfide mineralization, (2) uranium, and (3) post-uranium quartz-carbonate-sulfide mineralization. (1) K-Ar ages for white mica from wall rock alteration of the pre-uranium mineralization style range from 304.5 ± 5.8 to 307.6 ± 6.0 Ma coinciding with the post-orogenic exhumation of the Moldanubian orogenic root and retrograde-metamorphic equilibration of the high-grade metamorphic host rocks. The fluid inclusion record consists of low-salinity aqueous inclusions, together with H2O-CO2-CH4, CO2-CH4, and pure CH4 inclusions. The fluid inclusion, paragenetic, and isotope data suggest that the pre-uranium mineralization formed from a reduced low-salinity aqueous fluid at temperatures close to 300°C. (2) The uraniferous hydrothermal event is subdivided into the pre-ore, ore, and post-ore substages. K-Ar ages of pre-ore authigenic K-feldspar range from 296.3 ± 7.5 to 281.0 ± 5.4 Ma and coincide with the transcurrent reorganization of crustal blocks of the Bohemian Massif and with Late Stephanian to Early Permian rifting. Massive hematitization, albitization, and desilicification of the pre-ore altered rocks indicate an influx of oxidized basinal fluids to the crystalline rocks of the Moldanubian domain. The wide range of salinities of fluid inclusions is interpreted as a result of the large-scale mixing of basinal brines with meteoric water. The cationic composition of these fluids indicates extensive interaction with crystalline rocks. Chlorite thermometry yielded temperatures of 260°C to 310°C. During this substage, uranium was probably leached from the Moldanubian crystalline rocks. The hydrothermal alteration of the ore substage followed, or partly overlapped in time, the pre-ore substage alteration. K-Ar ages of illite from ore substage alteration range from 277.2 ± 5.5 to

  1. Mining and beneficiation of lunar ores

    NASA Technical Reports Server (NTRS)

    Bunch, T. E.; Williams, R. J.; Mckay, D. S.; Giles, D.

    1979-01-01

    The beneficiation of lunar plagioclase and ilmenite ores to feedstock grade permits a rapid growth of the space manufacturing economy by maximizing the production rate of metals and oxygen. A beneficiation scheme based on electrostatic and magnetic separation is preferred over conventional schemes, but such a scheme cannot be completely modeled because beneficiation processes are empirical and because some properties of lunar minerals have not been measured. To meet anticipated shipping and processing needs, the peak lunar mining rate will exceed 1000 tons/hr by the fifth year of operation. Such capabilities will be best obtained by automated mining vehicles and conveyor systems rather than trucks. It may be possible to extract about 40 kg of volatiles (60 percent H2O) by thermally processing the less than 20 micron ilmenite concentrate extracted from 130 tons of ilmenite ore. A thermodynamic analysis of an extraction process is presented.

  2. 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.

  3. Geology, petrology, and chemistry of the Leadville Dolomite: host for uranium at the Pitch Mine, Saguache County, Colorado

    USGS Publications Warehouse

    Nash, J. Thomas

    1979-01-01

    Newly documented uranium ore in the Pitch Mine occurs chiefly in brecciated Mississippian Leadville Dolomite along the Chester reverse fault zone, and to a lesser extent in sandstone, siltstone, and carbonaceous shale of the Pennsylvanian Belden Formation and in Precambrian granitic rocks and schist. Uranium-mineralized zones are generally thicker, more consistent, and of higher grade in dolomite than in other hosts, and roughly 50 percent of the new reserves are in dolomite. Strong physical control by dolomite is evident, as this is the only lithology that is pervasively brecciated within the fault slices that make up the footwall of the reverse fault zone. Other lithologies tend to either remain unbroken or undergo ductile deformation. Chemical controls are subtle and appear to involve chiefly formation of FeS2 as pyrite and marcasite, which accompany uranium. Leadville Dolomite in the area is about 130 m thick and is predominantly nonfossiliferous dolomicrite. In the Pitch Mine, Leadville Dolomite is bound by faults and maximum known thickness is about 17 m. Mud texture, paucity of fossils and other allochems, thin laminations, and probable algal mat structures suggest sedimentation in a tidal-flat (possibly supratidal) environment. Preservation of mud texture and lack of replacement features indicate that dolomitization was an early, prelithification process, as in modern tidal flats, and produced a chemically and texturally uniform rock over tens of meters with relatively few limestone beds surviving. The sedimentary and diagenetic environment of the tidal-flat dolomite, apparently most favorable for uranium deposits, probably obtained over a large area and should consistute an exploration target over a broad area of central Colorado. Carbonate rocks of the Belden Formation, in contrast to those of the Leadville, contain calcite in great excess of dolomite, more than 5 percent silt-size quartz and clay, and abundant fossils and oolites. Belden limestones

  4. National Uranium Resource Evaluation: Denver Quadrangle, Colorado

    SciTech Connect

    Hills, F.A.; Dickinson, K.A.; Nash, J.T.; Otton, J.K.; Dodge, H.W.; Granger, H.C.; Robinson, K.; McDonnell, J.R.; Yancey, C.L.

    1982-09-01

    Nine areas in the Denver 1/sup 0/ x 2/sup 0/ Quadrangle, Colorado have been identified as favorable for the occurrence of uranium deposits containing a minimum of 100 tons U/sub 3/O/sub 8/ at grades of 0.01% or better. Six of these areas are in metamorphic and igneous rocks of the Front Range, one is in sedimentary rocks of South Park, and two are in sedimentary rocks of the Great Plains. Favorable areas and the classes of deposits for which they are thought to be favorable are: Area A, The Foothills Favorable Environment (700 km/sup 2/ to a depth of 1500 m); Areas B-D, The Silver Plume Granite Favorable Environment; Area E, Southern Elkhorn Upthrust Favorable Environment; Area F, South Park Favorable Environments (27 km/sup 2/ in units of variable thickness); Area G, Dawson Arkose Favorable Environment (3600 km/sup 2/ with an estimated thickness of 50 m); and Area H, Fox Hills Formation Favorable Environment (700 km/sup 2/ with an estimated thickness of 38 m). Other areas and environments in the Denver Quadrangle have uranium occurences and some have yielded small amounts of uranium ore in the past (for example the Central City district). These areas are ranked as unfavorable because in our judgment the evidence does not suggest favorability for deposits of the minimum size. However, neither empirical data nor genetic models for uranium deposits are adequate presently to make determinations of favorability with confidence, and changes of rank are to be expected in the future.

  5. Uranium mining: ore treatment and environmental control. January 1975-1981 (citations from the International Information Service for the Physics and Engineering Communities Data Base). Report for Jan 75-May 81

    SciTech Connect

    Not Available

    1981-05-01

    The problems associated with uranium mining are covered with respect to both technological and political aspects. Environmental pollution due to radioactive materials, radiation protection and monitoring for personnel are emphasized. The economics of the US mining industry is also covered. (Contains 40 citations fully indexed and including a title list.)

  6. Wall-rock argillic alteration and uranium mineralization of the northwestern Strel'tsovka caldera

    NASA Astrophysics Data System (ADS)

    Andreeva, O. V.; Golovin, V. A.; Petrov, V. A.

    2010-02-01

    Alteration of rocks and localization of uranium mineralization in the northwestern Strel’tsovka caldera are exemplified in the Dal’nee deposit. In the main parameters of hydrothermal mineralization (temperature, pH, pressure, and composition of solution), the Dal’nee deposit differs from the deposits of the Strel’tsovka ore field located in the central part of the caldera. The localization of high-grade stratiform orebodies are interpreted in light of kinematic relations between steeply and gently dipping faults that formed in the tectonic setting of the NE-SW-trending, long-living, right-lateral, strike-slip faulting. The wide halos of argillic alteration and the structural control of uranium mineralization are caused by the fact that the deposit is located at the margin of the geological block, which has developed since the Late Triassic in a regime of extension (pull-apart) to form a depression, which is arranged en echelon relative to the main caldera and comparable to it in area. Currently, this depression is overlapped by sediments of the Sukhoi Urulyungui Basin. Such a structure markedly increases the probability of finding hidden uranium ores associated with low-temperature argillic alteration in the volcanosedimantary rocks and granitoid basement of the northwestern Strel’tsovka caldera.

  7. The genesis of ores

    SciTech Connect

    Brimhall, G. )

    1991-05-01

    Human history and technology have been shaped by metals. How did they become concentrated in minable deposits located so conveniently near the earth's surface The author explains the mechanisms of fluid transport-by magma, water and even air and wind-responsible for the chemical and physical interactions that created bodies of metallic ores throughout geologic history. From their formation to their modification at the surface of the earth, ore deposits are geologically transitory and reflect dynamic processes within the earth as well as atmospheric and climatic influences on hydrologic systems. As highly reactive supracrustal systems, they then serve as geochemical sensors providing a powerful record and set of tracer elements for deducing the history, transport paths and forces operative in the crust.

  8. Hauling urban ore

    SciTech Connect

    Lueck, P.A. )

    1991-05-01

    This paper reports that during the last few years, many railroads have viewed this country's growing MSW disposal problem as mountains of urban ore, referring to the potential revenues in its transportation. Much to the chagrin of the railroads, however, few endeavors to mine this new market have panned out. The MSW disposal problem is most acute in the Northeast, where numerous urban landfills were due to close early this year. Unfortunately, large-scale mass movement of MSW by railroads in the Northeast have failed to materialize. At least one railroad in the West is actively transporting MSW via rail. On April 1, 1991, the Union Pacific (UP) began transporting MSW in double stack containers from Seattle, Wash., to a landfill in Arlington, Ore. Working with Washington Waste Systems, the UP upgraded part of its trackage and dedicated space and equipment to serve that city's disposal needs.

  9. Potential Impacts of Legacy and Current Uranium Mining in the Grand Canyon Region of Northern Arizona

    NASA Astrophysics Data System (ADS)

    Bills, D. J.

    2012-12-01

    The Grand Canyon region in Northern Arizona contains high grade uranium resources hosted in geologic features called breccia pipes that represent an important component of the Nation's energy resource base. The exploration and extraction of uranium ore from these deposits poses potential risks to humans and biota of the Grand Canyon watershed. These issues led the Secretary of the Interior to a Record of Decision in January 2012 to withdraw over a million acres of federal lands in the region from mineral entry for the next 20 years. Dissolved uranium and other major ions and trace elements occur naturally in surface water and in groundwater as a result of precipitation infiltrating from the surface to perched water-bearing zones in contact with mineralized breccia pipes or in contact with sandstones with high trace element content, and to underlying regional aquifers. Discharge from these water-bearing zones and aquifers occur as seeps and springs throughout the region and provide valuable habitat and water sources for plants and animals. Runoff and groundwater flow in the Grand Canyon region is also a component of the water supply for over 25 million people in the Southwestern United States. Soil and sediment in the region can naturally contain as much a 5.6 micrograms per gram of uranium and naturally occurring dissolved uranium in groundwater is about 5.0 μg/L or less, except in proximity to uranium ore bodies where it tends to be greater. The current discharge of dissolved uranium from the Grand Canyon region to Lake Mead have concentrations of 4.0 μg/L or less resulting in a total annual load of uranium delivered to Lake Mead of about 60 tons per year. Increased amounts of radioactive materials and trace metals on the surface and in groundwater are related to uranium mining activity in the watershed in the 1970s and 1980s. Monitoring and data collection from 2010 to 2012 confirm this legacy impact in some parts of the Grand Canyon watershed, but have yet to

  10. 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.

  11. ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE MINES ABOVE AT THE RIDGELINE AND TO THE RIGHT WAS CONVEYED TO THIS AREA AND DUMPED INTO THE SHAFT AT CENTER. THIS SHAFT OPENS INTO THE ADIT AT BOTTOM CENTER. THERE IS ANOTHER SHAFT OPENING INTO THE ADIT JUST ABOVE THE ADIT BEHIND THE STONE WALL. THE ORE WAS LOADED INTO TRAM CARS INSIDE THE ADIT AND CONVEYED ON TRACKS TO THE TRESTLE LEADING TO THE PRIMARY ORE BIN AT THE TRAM TERMINAL. TRACKS CAN BE SEEN LEADING FROM THE ADIT AND TO THE LEFT. THE ORE WAS THEN DUMPED INTO A CHUTE AT THE END OF THE TRESTLE CARRYING IT INTO THE ORE BIN AT THE TRAM TERMINAL(SEE CHUTE ON CA-291-30). - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  12. 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.

  13. China's emergence as the world's leading iron-ore-consuming country

    USGS Publications Warehouse

    Kirk, W.S.

    2004-01-01

    China has become the leading iron ore consuming nation, and, based on recent steel production capacity increases and plans for more, its consumption will almost certainly to continue to grow. China's iron ore industry, however, faces a number of problems. China's iron ore is low-grade, expensive to process, and its mines are being depleted. For many Chinese steelmakers, particularly in the coastal regions, the delivered cost of domestic iron ore, is more than the delivered cost of foreign ore. Thus China's iron ore imports are expected to increase. As China's growth continues, it will almost certainly surpass Japan to become the leading iron ore importing country as well. Without China's increasing appetite for iron ore, the world iron ore market would be flat or declining. China's recent imports largely offset the slump in demand in North America and Europe. China is regarded by the iron ore industry as the growth sector for the next decade. Although Chinese imports are expected to continue their rapid increase and imports in other Asian countries are expected to continue growing, there appears to be enough greenfield and expansion projects to meet future demand for iron ore worldwide. Present suppliers of iron ore, Australia, Brazil, India, and South Africa, will probably be the chief beneficiaries of China's increasing consumption of iron ore. How long China can continue its extraordinary growth is the primary issue for the future of the iron ore industry. Based on the number and size of planned blast furnaces it appears that China's growth could continue for several more years. ?? 2004 Taylor and Francis.

  14. Geochemical reconnaissance for uranium occurrences in the Notch Peak intrusive area, House Range, Millard County, Utah

    USGS Publications Warehouse

    Cadigan, R.A.; Robinson, Keith

    1982-01-01

    Samples collected from the contact metamorphic zone of the Notch Peak intrusive area, House Range, Millard County, Utah, indicate the occurrence of low-grade uranium and thorium ore. Maximum abundances in the altered mineralized rocks in the contact zone are 450 ppm uranium and 480 ppm thorium. Interpretation of factor analysis of the spectrochemical and delayed neutron analytical data suggests the presence of five geological factors which account for 82 percent of element covariance of 34 elements in 61 samples. The factors are identified as (1) limestone source rock reactions; (2) monzonite source rock reactions; (3) hydrothermal element group 1; (4) rare earth group; and (5) hydrothermal element group 2. The last factor effects the distribution of, primarily, beryllium, uranium, copper, molybdenum, tungsten, niobium, and secondarily, thorium, tin, and zinc; it is identified as the prime mineralization factor. The Notch Peak intrusive area has been a tungsten producing area since before the 1940's and the location of small-scale gold placer operations. This reconnaissance study was a 'follow-up' of uranium anomaly data which were developed during the U.S. Dept. of Energy National Uranium Resource Evaluation (NURE) program in 1978-80.

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

    SciTech Connect

    E. Schneider; B. Carlsen; E. Tavrides; C. van der Hoeven; U. Phathanapirom

    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, water 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.

  16. 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

  17. 76 FR 52688 - Notice of Intent To Prepare an Environmental Impact Statement for the Sheep Mountain Uranium...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ... underground mining methods to extract the ore. Uranium recovery would be performed on-site using heap leach... underground mining may use diesel-powered equipment and blasting to extract and transport the ore to the heap... of the pit. After being received at the processing facility, ore would be placed on the...

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

    USGS Publications Warehouse

    Nash, J. Thomas

    1977-01-01

    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.

  19. Modelling study on uranium migration in rocks under weathering condition

    SciTech Connect

    Ohnuki, Toshihiko; Isobe, Hiroshi; Sato, Tsutomu; Yanase, Nobuyuki; Murakami, Takashi

    1995-12-31

    A modelling study has been completed to understand the effect of rock alteration on uranium migration at the Koongarra ore deposit, Australia. The model considers the weathering process, the mechanism and rate of chlorite alteration, a major mineral of the host rock, and assumes the presence of reversible sorption sites of chlorite and the presence of reversible and irreversible sorption sites of the weathering products. One- and two-dimensional, calculated uranium concentrations were compared with those observed. Good agreement between the calculated and observed uranium concentration profiles was obtained only when an appropriate fraction of uranium is fixed to the irreversible sorption sites of Fe-minerals produced during weathering of chlorite. On the other hand, the conventional Kd model failed to estimate an adequate uranium concentration profile. The results suggest that the fixation of uranium to Fe-minerals has dominated the migration of uranium in the vicinity of the Koongarra ore deposit.

  20. 10 CFR 760.1 - Uranium leases on lands controlled by DOE. (Domestic Uranium Program Circular No. 760.1, formerly...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Uranium Program Circular No. 760.1, formerly (AEC) Domestic Uranium Program Circular 8, 10 CFR 60.8). 760... Circular 8, 10 CFR 60.8). (a) What this section does. This section sets forth regulations governing the... to all ores and other uranium- or vanadium-bearing material not removed from the leased...

  1. 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.

  2. Ferride geochemistry of Swedish precambrian iron ores

    NASA Astrophysics Data System (ADS)

    Loberg, B. E. H.; Horndahl, A.-K.

    1983-10-01

    Chemical analysis for major and trace elements have been performed on 30 Swedish Precambrian iron ores and on some from Iran and Chile. The Swedish ores consist of apatite iron ores, quartz-banded iron ores, skarn and limestone iron ores from the two main ore districts of Sweden, the Bergslagen and the Norrbotten province. Some Swedish titaniferous iron ores were also included in the investigation. The trace element data show that the Swedish ores can be subdivided into two major groups: 1. orthomagmatic and exhalative, 2. sedimentary. Within group 1 the titaniferous iron ores are distinguished by their high Ti-contents. From the ferride contents of the Kiruna apatite iron ores, the ores are considered to be mobilization products of skarn iron ores from the Norbotten province.

  3. URANIUM PRECIPITATION PROCESS

    DOEpatents

    Thunaes, A.; Brown, E.A.; Smith, H.W.; Simard, R.

    1957-12-01

    A method for the recovery of uranium from sulfuric acid solutions is described. In the present process, sulfuric acid is added to the uranium bearing solution to bring the pH to between 1 and 1.8, preferably to about 1.4, and aluminum metal is then used as a reducing agent to convert hexavalent uranium to the tetravalent state. As the reaction proceeds, the pH rises amd a selective precipitation of uranium occurs resulting in a high grade precipitate. This process is an improvement over the process using metallic iron, in that metallic aluminum reacts less readily than metallic iron with sulfuric acid, thus avoiding consumption of the reducing agent and a raising of the pH without accomplishing the desired reduction of the hexavalent uranium in the solution. Another disadvantage to the use of iron is that positive ferric ions will precipitate with negative phosphate and arsenate ions at the pH range employed.

  4. The New Generation of Uranium In Situ Recovery Facilities: Design Improvements Should Reduce Radiological Impacts Relative to First Generation Uranium Solution Mining Plants

    SciTech Connect

    Brown, S.H.

    2008-07-01

    In the last few years, there has been a significant increase in the demand for Uranium as historical inventories have been consumed and new reactor orders are being placed. Numerous mineralized properties around the world are being evaluated for Uranium recovery and new mining / milling projects are being evaluated and developed. Ore bodies which are considered uneconomical to mine by conventional methods such as tunneling or open pits, can be candidates for non-conventional recovery techniques, involving considerably less capital expenditure. Technologies such as Uranium In Situ Leaching / In Situ Recovery (ISL / ISR - also referred to as 'solution mining'), have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and are expected to make a significant contribution to overall world wide uranium supplies over the next ten years. Commercial size solution mining production facilities have operated in the US since the mid 1970's. However, current designs are expected to result in less radiological wastes and emissions relative to these 'first' generation plants (which were designed, constructed and operated through the 1980's). These early designs typically used alkaline leach chemistries in situ including use of ammonium carbonate which resulted in groundwater restoration challenges, open to air recovery vessels and high temperature calcining systems for final product drying vs the 'zero emissions' vacuum dryers as typically used today. Improved containment, automation and instrumentation control and use of vacuum dryers in the design of current generation plants are expected to reduce production of secondary waste byproduct material, reduce Radon emissions and reduce potential for employee exposure to uranium concentrate aerosols at the back end of the milling process. In Situ Recovery in the U.S. typically involves the circulation of groundwater, fortified with oxidizing (gaseous oxygen e.g) and complexing agents (carbon

  5. Can I Trust ORE Reports?

    ERIC Educational Resources Information Center

    Feedback, 1984

    1984-01-01

    This issue of FEEDBACK, a newsletter produced by the the Austin Independent School District Office of Research and Evaluation (ORE), illustrates the accuracy, validity, and fairness of ORE reports. The independence of the reports is explained. Internal and external quality controls are used to ensure reliability and accuracy of the reports.…

  6. Evolution of uranium and thorium minerals

    NASA Astrophysics Data System (ADS)

    Hazen, R. M.; Ewing, R. C.; Sverjensky, D. A.

    2009-12-01

    The origins and near-surface distributions of the approximately 250 known uranium and/or thorium minerals elucidate principles of mineral evolution. This history can be divided into four phases. The first, from ~4.5 to 3.5 Ga, involved successive concentrations of uranium and thorium from their initial uniform trace distribution into magmatic-related fluids from which the first U4+ and Th4+ minerals, uraninite (UO2), thorianite (ThO2) and coffinite (USiO4), precipitated in the crust. The second period, from ~3.5 to 2.2 Ga, saw the formation of large low-grade concentrations of detrital uraninite (containing several weight percent Th) in the Witwatersrand-type quartz-pebble conglomerates deposited in a highly anoxic fluvial environment. Abiotic alteration of uraninite and coffinite, including radiolysis and auto-oxidation caused by radioactive decay and the formation of helium from alpha particles, may have resulted in the formation of a limited suite of uranyl oxide-hydroxides. Earth’s third phase of uranium mineral evolution, during which most known U minerals first precipitated from reactions of soluble uranyl (U6+O2)2+ complexes, followed the Great Oxidation Event (GOE) at ~2.2 Ga and thus was mediated indirectly by biologic activity. Most uraninite deposited during this phase was low in Th and precipitated from saline and oxidizing hydrothermal solutions (100 to 300°C) transporting (UO2)2+-chloride complexes. Examples include the unconformity- and vein-type U deposits (Australia and Canada) and the unique Oklo natural nuclear reactors in Gabon. The onset of hydrothermal transport of (UO2)2+ complexes in the upper crust may reflect the availability of CaSO4-bearing evaporites after the GOE. During this phase, most uranyl minerals would have been able to form in the O2-bearing near-surface environment for the first time through weathering processes. The fourth phase of uranium mineralization began approximately 400 million years ago, as the rise of land plants

  7. National Uranium Resource Evaluation, Glens Falls Quadrangle: New York, Vermont, and New Hampshire

    SciTech Connect

    McHone, J.G.; Wagener, H.D.

    1982-06-01

    Grenville anatectic pegmatites of the Adirondack Mountains of New York are a favorable environment for the occurrence of uranium deposits of not less than 100 tons U/sub 3/O/sub 8/ at an average grade of not less than 100 ppM U/sub 3/O/sub 8/. The pegmatites have local high concentrations of U/sub 3/O/sub 8/ in uraninite and lesser concentrations in allanite, uranothorite, and rare-earth minerals. Metamorphosed anatectic pegmatites of the Mt. Holly Complex in the Green Mountains of Vermont are a favorable environment for uranium deposits. Allanite is prominent in thorium-rich pegmatites, but intergranular pitchblende is the principal ore mineral of uranium-rich pegmatites. Mt. Holly pegmatite appears to be Grenville pegmatite with part of the uranium removed by Paleozoic metamorphism. The Mt. Holly Complex is a favorable environment for vein-type deposits of uranium in biotite gneisses, mica schists, and quartzites. Pitchblende is concentrated along minor thrust faults and steeply dipping fault zones. Disseminations of pitchblende occur along biotite lamellae in gneissoid and schistose rocks in the vicinity of faults, and in pods and lenses of biotite-rich schist in both highly contorted rocks and interlayered gneisses and schists. Carnotite and torbernite commonly occur along faults, fractures, and biotite lamellae in uraniferous rocks. The two-mica granite of the small Sunapee pluton in New Hampshire contains authigenic favorable areas consisting of closely spaced Mesozoic fractures filled with hexavalent uranium minerals. The uranium is being leached from the granite by ground water.

  8. 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...

  9. 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...

  10. 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...