Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland

USGS Publications Warehouse

Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.

1996-01-01

Lead-isotopic data on galena samples collected from a paragenetically constrained suite of samples from the Silesian-Cracow ore district show no regional or paragenetically controlled lead-isotopic trends within the analytical reproducibility of the measurements. Furthermore, the new lead-isotopic data agree with previously reported lead-isotopic results (R. E. Zartman et al., 1979). Sulfur-isotopic analyses of ores from the Silesian-Cracow district as well as from vein ore from the Gory Swietokrzyskie Mts. and the Myszkow porphyry copper deposit, when coupled with trace-element data from the galena samples, clearly discriminate different hydrothermal ore-forming events. Lead-isotopic data from the Permian and Miocene evaporite deposits in Poland indicate that neither of these evaporite deposits were a source of metals for the Silesian-Cracow district ores. Furthermore, lead-isotopic data from these evaporite deposits and the shale residues from the Miocene halite samples indicate that the crustal evolution of lead in the central and western European platform in southern Poland followed normal crustal lead-isotopic growth, and that the isotopic composition of crustal lead had progressed beyond the lead-isotopic composition of lead in the Silesian-Cracow ores by Permian time. Thus, Mesozoic and Tertiary sedimentary flysch rocks can be eliminated as viable source rocks for the metals in the Silesian-Cracow Mississippi Valley-type (MVT) deposits. The uniformity of the isotopic composition of lead in the Silesian-Cracow ores, when coupled with the geologic evidence that mineralization must post-date Late Jurassic faulting (E. Gorecka, 1991), constrains the geochemical nature of the source region. The source of the metals is probably a well-mixed, multi-cycle molasse sequence of sedimentary rocks that contains little if any Precambrian metamorphic or granitic clasts (S. E. Church, R. B. Vaughn, 1992). If ore deposition was post Late Jurassic (about 150 m. y.) or later as indicated by the geologic evidence, the source rocks probably contained elevated concentrations of Zn and Pb (75-100 ppm), and relatively low concentrations of U and Th (2 and 8 ppm or less, respectively). The Carboniferous coal-bearing molasse rocks of the Upper Silesian Coal Basin are a prime candidate for such a source region. The presence of ammonia and acetate in the fluid inclusions (Viets et al., 1996a) also indicate that the Carboniferous coal-bearing molasse sequence in the Upper Silesian Coal Basin may have been a suitable pathway for the MVT ore fluids. The lead-isotopic homogeneity, when coupled with the sulfur-isotopic heterogeneity of the ores suggests that mixing of a single metal-bearing fluid with waters from separate aquifers containing variable sulfur-isotopic compositions in karsts in the Muschelkalk Formation of Middle Triassic age may have been responsible for the precipitation of the ores of the Silesian-Cracow district.

Intensification of the Reverse Cationic Flotation of Hematite Ores with Optimization of Process and Hydrodynamic Parameters of Flotation Cell

NASA Astrophysics Data System (ADS)

Poperechnikova, O. Yu; Filippov, L. O.; Shumskaya, E. N.; Filippova, I. V.

2017-07-01

The demand of high grade iron ore concentrates is a major issue due to the depletion of rich iron-bearing ores and high competitiveness in the iron ore market. Iron ore production is forced out to upgrade flowsheets to decrease the silica content in the pelettes. Different types of ore have different mineral composition and texture-structural features which require different mineral processing methods and technologies. The paper presents a comparative study of the cationic and anionic flotation routes to process a fine-grain oxidized iron ore. The modified carboxymethyl cellulose was found as the most efficient depressant in reverse cationic flotation. The results of flotation optimization of hematite ores using matrix of second-order center rotatable uniform design allowed to define the collector concentration, impeller rotation speed and air flowrate as the main flotation parameters impacting on the iron ore concentrate quality and iron recovery in a laboratory flotation machine. These parameters have been selected as independent during the experiments.

Phytostabilisation potential of lemon grass (Cymbopogon flexuosus (Nees ex Stend) Wats) on iron ore tailings.

PubMed

Mohanty, M; Dhal, N K; Patra, P; Das, B; Reddy, P S R

2012-01-01

The present pot culture study was carried out for the potential phytostabilisation of iron ore tailings using lemon grass (Cymbopogon flexuosus) a drought tolerant, perennial, aromatic grass. Experiments have been conducted by varying the composition of garden soil (control) with iron ore tailings. The various parameters, viz. growth of plants, number of tillers, biomass and oil content of lemon grass are evaluated. The studies have indicated that growth parameters of lemon grass in 1:1 composition of garden soil and iron ore tailings are significantly more (-5% increase) compared to plants grown in control soil. However, the oil content of lemon grass in both the cases more or less remained same. The results also infer that at higher proportion of tailings the yield of biomass decreases. The studies indicate that lemongrass with its fibrous root system is proved to be an efficient soil binder by preventing soil erosion.

Differentiation of commercial vermiculite based on statistical analysis of bulk chemical data: Fingerprinting vermiculite from Libby, Montana U.S.A

USGS Publications Warehouse

Gunter, M.E.; Singleton, E.; Bandli, B.R.; Lowers, H.A.; Meeker, G.P.

2005-01-01

Major-, minor-, and trace-element compositions, as determined by X-ray fluorescence (XRF) analysis, were obtained on 34 samples of vermiculite to ascertain whether chemical differences exist to the extent of determining the source of commercial products. The sample set included ores from four deposits, seven commercially available garden products, and insulation from four attics. The trace-element distributions of Ba, Cr, and V can be used to distinguish the Libby vermiculite samples from the garden products. In general, the overall composition of the Libby and South Carolina deposits appeared similar, but differed from the South Africa and China deposits based on simple statistical methods. Cluster analysis provided a good distinction of the four ore types, grouped the four attic samples with the Libby ore, and, with less certainty, grouped the garden samples with the South Africa ore.

On prediction and discovery of lunar ores

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Colson, Russell O.; Vaniman, David

1991-01-01

Sampling of lunar material and remote geochemical, mineralogical, and photogeologic sensing of the lunar surface, while meager, provide first-cut information about lunar composition and geochemical separation processes. Knowledge of elemental abundances in known lunar materials indicates which common lunar materials might serve as ores if there is economic demand and if economical extraction processes can be developed, remote sensing can be used to extend the understanding of the Moon's major geochemical separations and to locate potential ore bodies. Observed geochemical processes might lead to ores of less abundant elements under extreme local conditions.

The effect of smelting time and composition of palm kernel shell charcoal reductant toward extractive Pomalaa nickel laterite ore in mini electric arc furnace

NASA Astrophysics Data System (ADS)

Sihotang, Iqbal Huda; Supriyatna, Yayat Iman; Ismail, Ika; Sulistijono

2018-04-01

Indonesia is a country that is rich in natural resources. Being a third country which has a nickel laterite ore in the world after New Caledonia and Philippines. However, the processing of nickel laterite ore to increase its levels in Indonesia is still lacking. In the processing of nickel laterite ore into metal, it can be processed by pyrometallurgy method that typically use coal as a reductant. However, coal is a non-renewable energy and have high enough levels of pollution. One potentially replace is the biomass, that is a renewable energy. Palm kernel shell are biomass that can be used as a reductant because it has a fairly high fix carbon content. This research aims to make nickel laterite ores become metal using palm kernel shell charcoal as reductant in mini electric arc furnace. The result show that the best smelting time of this research is 60 minutes with the best composition of the reductant is 2,000 gram.

Solubility and chemistry of materials encountered by beryllium mine and ore extraction workers: relation to risk.

PubMed

Deubner, David C; Sabey, Philip; Huang, Wenjie; Fernandez, Diego; Rudd, Abigail; Johnson, William P; Storrs, Jason; Larson, Rod

2011-10-01

Beryllium mine and ore extraction mill workers have low rates of beryllium sensitization and chronic beryllium disease relative to the level of beryllium exposure. The objective was to relate these rates to the solubility and composition of the mine and mill materials. Medical surveillance and exposure data were summarized. Dissolution of BeO, ore materials and beryllium hydroxide, Be(OH)(2) was measured in synthetic lung fluid. The ore materials were more soluble than BeO at pH 7.2 and similar at pH 4.5. Be(OH)(2) was more soluble than BeO at both pH. Aluminum dissolved along with beryllium from ore materials. Higher solubility of beryllium ore materials and Be(OH)(2) at pH 7.2 might shorten particle longevity in the lung. The aluminum content of the ore materials might inhibit the cellular immune response to beryllium.

Lead and zinc dust depositions from ore trains characterised using lead isotopic compositions.

PubMed

Kristensen, L J; Taylor, M P; Morrison, A L

2015-03-01

This study investigates an unusual source of environmental lead contamination - the emission and deposition of lead and zinc concentrates along train lines into and out of Australia's oldest silver-lead-zinc mine at Broken Hill, Australia. Transport of lead and zinc ore concentrates from the Broken Hill mines has occurred for more than 125 years, during which time the majority was moved in uncovered rail wagons. A significant amount of ore was lost to the adjoining environments, resulting in soil immediately adjacent to train lines elevated with concentrations of lead (695 mg kg(-1)) and zinc (2230 mg kg(-1)). Concentrations of lead and zinc decreased away from the train line and also with depth shown in soil profiles. Lead isotopic compositions demonstrated the soil lead contained Broken Hill ore in increasing percentages closer to the train line, with up to 97% apportioned to the mined Broken Hill ore body. SEM examination showed ceiling dusts collected from houses along the train line were composed of unweathered galena particles, characteristic of the concentrate transported in the rail wagons. The loss of ore from the uncovered wagons has significantly extended the environmental footprint of contamination from local mining operations over an area extending hundreds of kilometres along each of the three train lines.

Biomediated continuous release phosphate fertilizer

DOEpatents

Goldstein, Alan H.; Rogers, Robert D.

1999-01-01

A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed.

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

NASA Astrophysics Data System (ADS)

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

2012-04-01

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

Characterization of Uranium Ore Concentrate Chemical Composition via Raman Spectroscopy

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

Su, Yin-Fong; Tonkyn, Russell G.; Sweet, Lucas E.

Uranium Ore Concentrate (UOC, often called yellowcake) is a generic term that describes the initial product resulting from the mining and subsequent milling of uranium ores en route to production of the U-compounds used in the fuel cycle. Depending on the mine, the ore, the chemical process, and the treatment parameters, UOC composition can vary greatly. With the recent advent of handheld spectrometers, we have chosen to investigate whether either commercial off-the-shelf (COTS) handheld devices or laboratory-grade Raman instruments might be able to i) identify UOC materials, and ii) differentiate UOC samples based on chemical composition and thus suggest themore » mining or milling process. Twenty-eight UOC samples were analyzed via FT-Raman spectroscopy using both 1064 nm and 785 nm excitation wavelengths. These data were also compared with results from a newly developed handheld COTS Raman spectrometer using a technique that lowers background fluorescence signal. Initial chemometric analysis was able to differentiate UOC samples based on mine location. Additional compositional information was obtained from the samples by performing XRD analysis on a subset of samples. The compositional information was integrated with chemometric analysis of the spectroscopic dataset allowing confirmation that class identification is possible based on compositional differences between the UOC samples, typically involving species such as U3O8, α-UO2(OH)2, UO4•2H2O (metastudtite), K(UO2)2O3, etc. While there are clearly excitation λ sensitivities, especially for dark samples, Raman analysis coupled with chemometric data treatment can nicely differentiate UOC samples based on composition and even mine origin.« less

Geochemical contrasts between Late Triassic ore-bearing and barren intrusions in the Weibao Cu-Pb-Zn deposit, East Kunlun Mountains, NW China: constraints from accessory minerals (zircon and apatite)

NASA Astrophysics Data System (ADS)

Zhong, Shihua; Feng, Chengyou; Seltmann, Reimar; Li, Daxin; Dai, Zhihui

2017-12-01

The Weibao copper-lead-zinc skarn deposit is located in the northern East Kunlun terrane, NW China. Igneous intrusions in this deposit consist of barren diorite porphyry (U-Pb zircon age of 232.0 ± 2.0 Ma) and ore-bearing quartz diorite and pyroxene diorite (U-Pb zircon ages of 223.3 ± 1.5 and 224.6 ± 2.9 Ma, respectively). Whole-rock major and trace element and accessory mineral (zircon and apatite) composition from these intrusions are studied to examine the different geochemical characteristics of ore-bearing and barren intrusions. Compared to the barren diorite porphyry, the ore-bearing intrusions have higher Ce4+/Ce3+ ratios of zircon and lower Mn contents of apatite, indicating higher oxidation state. Besides, apatite from the ore-bearing intrusions shows higher Cl contents and lower F/Cl ratios. These characteristics collectively suggest the higher productivity of ore-bearing quartz diorite and pyroxene diorite. When compared with ore-bearing intrusions from global porphyry Cu deposits, those from Cu-Pb-Zn skarn deposits display lower Ce4+/Ce3+ and EuN/EuN* ratios of zircon and lower Cl and higher F/Cl ratios of apatite. We conclude that these differences reflect a general geochemical feature, and that zircon and apatite composition is a sensitive tool to infer economic potential of magmas and the resulting mineralization types in intrusion-related exploration targets.

Krasnotur'insk Skarn copper ore field, Northern Urals: The U-Pb age of ore-controlling diorites and their place in the regional metallogeny

NASA Astrophysics Data System (ADS)

Grabezhev, A. I.; Ronkin, Yu. L.; Puchkov, V. N.; Gerdes, A.; Rovnushkin, M. Yu.

2014-06-01

The Krasnotur'insk skarn copper ore field known from the theoretical works of Academician K.S. Korzhinskii is located in the western part of the Tagil volcanic zone (in the area of the town of Krasnotur'insk). The ore field is composed of layered Devonian (Emsian) volcanosedimentary rocks intruded by small plutons of quartz diorites, diorites, and gabbrodiorites. Widespread pre-ore and intra-ore dikes of similar composition control the abundance of the andradite skarns formed after limestones and the magnetitesulfide and sulfide ore bodies formed after skarns. The LA-ICP-MS U-Pb concordant age of zircon from the quartz diorite of the Vasil'evsko-Moskalevskii pluton calculated by 16 analyses (16 crystals) is 407.7 ± 1.6 Ma (MSWD = 1.5). Taking into account the geological and petrogeochemical similarity of diorites of small plutons and intra-ore dikes, it is assumed that this age corresponds to the period of formation of the ore-magmatic system of the Krasnotur'insk skarn copper ore field. It was probably formed somewhat earlier than the Auerbakh montzonitic pluton and the accompanying skarn magnetite deposits in the south.

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

DOE PAGES

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

2014-04-13

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

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

PubMed

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

2014-07-01

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

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

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

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

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

Idetification of the chemical sedimentary protolish of the early Paleoproterozoic banded iron formation from Wuyang area, in the southern margin of the North China Craton

NASA Astrophysics Data System (ADS)

Lan, C.; Zhao, T.

2016-12-01

The Paleoproterozoic banded iron formation (BIF) from Wuyang area in the southern margin of the North China Craton (NCC) were metamorphosed under granulite facies, and are characterized with an assemblage of clinopyroxene, magnetite and orthopyroxene. Two types of iron ores can be identified on the basis of macro- and micro-textures: banded quartz-clinopyroxene (±othopyroxene) -magnetite ores and massive clinopyroxene-magnetite ores. Two-pyroxene geothermometry indicates that the primary counterparts of these ores have undergone metamorphism with a peak temperature of about 762±9°. Both the banded and massive ores have also similarly BIF-like REE+Y features, and thus are proposed to have all formed from chemical sediments. Similarly, clinopyroxenes from both types have BIF-like rare earth element compositions and are rich in Fe (16-23 wt.% FeOtotoal), further suggesting that they are primary Fe-Mg-Ca-rich chemical sediments during metamorphism. Slight enrichments of TiO2, Al2O3, Zr, Hf, Ta and Th of the Wuyang IF suggest relatively low detritus input. The massive ore have magnetite containing V, Cr and Ti much higher than those of the banded ores, suggesting that they may have undergone stronger secondary alteration possibly related to the intrusion of nearby pyroxenite plutons. Different ores have seawater-like REE+Y patterns with LREE depletions and positive anomalies of La, Eu, and Y, showing that granulite facies metamorphism did not essentially modify the primary compositions of the Wuyang IF deposited from paleo-seawater. Our results suggest less than 0.1% contribution from high-temperature hydrothermal fluids.

Biomediated continuous release phosphate fertilizer

DOEpatents

Goldstein, A.H.; Rogers, R.D.

1999-06-15

A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed. 13 figs.

Isotopic Variability of Mercury in Ore, Mine-Waste Calcine, and Leachates of Mine-Waste Calcine from Areas Mined for Mercury

PubMed Central

2009-01-01

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that δ202Hg values relative to NIST 3133 of calcine (up to 1.52‰) in the Terlingua district, Texas, are as much as 3.24‰ heavier than cinnabar (−1.72‰) prior to retorting. In addition, δ202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17‰ heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, δ202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff. PMID:19848142

Isotopic variability of mercury in ore, mine-waste calcine, and leachates of mine-waste calcine from areas mined for mercury

USGS Publications Warehouse

Stetson, S.J.; Gray, J.E.; Wanty, R.B.; Macalady, D.L.

2009-01-01

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that ??202Hg values relative to NIST 3133 of calcine (up to 1.52???) in the Terlingua district, Texas, are as much as 3.24??? heavier than cinnabar (-1.72???) prior to retorting. In addition, ??202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17??? heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, ??202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff. ?? 2009 American Chemical Society.

Nonlinear metallogeny and the depths of the earth

NASA Astrophysics Data System (ADS)

Shcheglov, A. D.; Govorov, I. N.

This book is concerned with the basic relations regarding a new approach in the field of knowledge of metallogenesis, taking into account the complex character of the mutual dependence between ore deposits, the structure of the earth's crust, and depth relations. The principles of nonlinear metallogeny are examined, giving attention to the development of the metallogenic science during the past few years, the formation of the concept 'nonlinear metallogeny', the main aspects of nonlinear metallogeny, the origin of the ore deposits and the characteristics of ore formations in the mantle, the parallel manifestation of ore-forming processes in the crust, sedimentary-hydrothermal ore formations and their place in nonlinear metallogeny, and various types of rock and ore formations. The structure, composition, and metalliferous characteristics found at various depth zones of the tectonosphere are discussed along with the geochemical and metallogenic heterogeneity in the mantle. General questions of nonlinear metallogeny are also investigated.

Metal cation exchange reactions of ore minerals in Fe-Mn crusts of the Marcus Wake Rise (Pacific Ocean) in aqueous-salt solutions

NASA Astrophysics Data System (ADS)

Novikov, G. V.; Bogdanova, O. Yu.; Melnikov, M. E.; Drozdova, A. N.; Lobus, N. V.; Shulga, N. A.

2017-12-01

It is shown that the reaction ability of metal cations of ore minerals in Fe-Mn crusts of the Marcus Wake Rise increases in the following manner: (Co2+ < Cu2+ < Ni2+) < (Mg2+ < Mn2+ < K+ ≈ Ca2+ ≈ Na+). The composition of the exchange complex of the ore minerals is constant and includes these metal cations. Ca2+ and Na+ are major contributors to the exchange capacity of the ore minerals. The capacity of the ore minerals by cations of alkali and base metals is 0.43-0.60 and 2.08-2.70 mg-equiv/g, respectively. The exchange capacity of the ore minerals by cations of base metals increases linearly with the increase in the MnO2 content of the crust and does not depend on the geographical locations of the Marcus Wake guyots.

In situ strontium and sulfur isotope investigation of the Ni-Cu-(PGE) sulfide ore-bearing Kevitsa intrusion, northern Finland

NASA Astrophysics Data System (ADS)

Luolavirta, Kirsi; Hanski, Eero; Maier, Wolfgang; Lahaye, Yann; O'Brien, Hugh; Santaguida, Frank

2018-01-01

The 2.06-Ga Kevitsa mafic-ultramafic intrusion in northern Finland hosts a large disseminated Ni-Cu-PGE deposit. The deposit occurs in the ultramafic olivine-pyroxene cumulates and shows a range in Ni tenors varying from 4-7 wt% (regular ore) to > 10 wt% (Ni-PGE ore). There are also a metal-poor sulfide mineralization (false ore) and contact mineralization that are uneconomic (Ni tenor < 4 wt%). The obtained 87Sr/86Sr(i) values of the Kevitsa ultramafic cumulates are highly radiogenic (> 0.7045) in comparison to the estimated depleted mantle Sr isotope ratio of 0.702 at 2.06 Ga. The sulfur δ 34S values are generally higher than + 2‰, which together with the Sr isotope data imply involvement of crustal material in the genesis of the Kevitsa intrusion and its ores. The 87Sr/86Sr(i) values obtained from the ore-bearing domain of the intrusion show stratigraphic variation and exceed 0.7050, with the maximum value reaching up to 0.7109. In contrast, in rocks around the ore domain, the initial Sr isotope compositions remain more or less constant (0.7047-0.7060) throughout the intrusive stratigraphy. The isotope data suggest that the ore-bearing domain of the intrusion represents a dynamic site with multiple injections of variably contaminated magma, whereas the surrounding part of the intrusion experienced a less vigorous emplacement history. No correlation is observed between the strontium and sulfur isotope compositions. This is explained by bulk assimilation of the silicate magma in a deeper staging magma chamber and variable assimilation of sulfur during magma transport into the Kevitsa magma chamber. The low level of metals in false ore and the Ni-depleted nature of its olivine suggest that some sulfides may have precipitated and deposited in the feeder conduit during the initial stage of magma emplacement. Cannibalization of early-formed sulfides by later magma injections may have been important in the formation of the economic ore deposit.

Geochemical features of the ore-bearing medium in uranium deposits in the Khiagda ore field

NASA Astrophysics Data System (ADS)

Kochkin, B. T.; Solodov, I. N.; Ganina, N. I.; Rekun, M. L.; Tarasov, N. N.; Shugina, G. A.; Shulik, L. S.

2017-09-01

The Neogene uranium deposits of the Khiagda ore field (KOF) belong to the paleovalley variety of the hydrogene type and differ from other deposits of this genetic type in the geological and geochemical localization conditions. The contemporary hydrogeochemical setting and microbiological composition of ore-bearing medium are discussed. The redox potential of the medium (Eh is as low as-400 mV) is much lower than those established at other hydrogenic deposits, both ancient Late Mesozoic and young Late Alpine, studied with the same methods in Russia, Uzbekistan, and southern Kazakhstan. The pH of subsurface water (6.86-8.13) differs in significant fluctuations both between neighboring deposits and within individual ore lodes. Hydrogen-forming and denitrifying bacteria are predominant in microbiological populations, whereas sulfate-reducing bacteria are low-active. The consideration of these factors allowed us to describe the mechanism of uranium ore conservation as resulting from the development of the cryolithic zone, which isolates ore lodes from the effect of the external medium. Carbonated water supplied from the basement along fault zones also participates in the formation of the present-day hydrogeochemical setting. Based on the features of the ore-bearing medium, we propose a method of borehole in situ acid leaching to increase the efficiency of mining in the Khiagda ore field.

Determining Prehistoric Mining Practices in Southeastern Europe Using Copper Isotopes

NASA Astrophysics Data System (ADS)

Powell, Wayne; Mathur, Ryan; Bankoff, H. Arthur; Bulatović, Aleksandar; Filipović, Vojislav

2017-04-01

Copper was first smelted from malachite at 5000 BCE in Serbia. There the Eneolithic (Copper Age) began with the production of small jewelry pieces and progressed to the casting of massive copper tools near its end, approximately 2000 years later. However, copper metallurgy in southeastern Europe ceased or significantly decreased in the later third millennium, several centuries before the Bronze Age began. Whether this metallurgical hiatus was the result a cultural shift or depletion of natural resources remains an ongoing subject of debate. It has been speculated that the marked reduction in metal production at the Eneolithic-Bronze Age transition was due to the exhaustion of surficial weathered oxide ores and the technical inability to smelt the underlying sulfide minerals. The behavior of copper isotopes in near-surface environments allows us to differentiate highly weathered oxide ores that occur at Earth's surface from non-weathered sulfide ores that occur at greater depth. The oxidation of copper generates fluids and associated minerals that are enriched in the 65Cu isotope. Thus, oxidative weathering of sulfide ores leads to the development of three stratified isotopic reservoirs for copper: 1) oxides above the water table that are enriched in 65Cu; 2) residual weathered sulfides minerals at the water table that are depleted in 65Cu; and 3) non-fractionated, non-weathered sulfide ore below the water table. And so, the transformative shift to sulfide-based metallurgy will be delineated by a significant decrease in δ65Cu in copper artifacts corresponding to the first use of 65Cu-depleted residual ore. The degree of variability of primary ore composition from numerable ore deposits would likely result in the overlap of copper isotope composition between populations of artifacts. Therefore, shifts in the mean copper isotope values and associated standard deviations would best reflect changes in ores use. A baseline value of -0.2‰ ±0.5 (1) was determined from an average of 164 published measurements from chalcopyrite and bornite from 8 epithermal and massive sulfide deposits. Twenty-two (88%) of Eneolithic artifacts (n=25) have values greater than this, whereas eight (73%) of the Early Bronze age artifacts (n=11) yield compositions less than -0.2‰. The mean of Middle Bronze Age, Late Bronze Age and Early Iron Age (n=86) cluster near -0.2‰. This pattern is consistent with a progression to the mining of ore assemblages from increasing depths through prehistory. The shift from 65Cu-enriched to 65Cu-depleted copper in artifacts across the Eneolithic-Bronze Age boundary at 2500 BCE indicates that accessible near-surface oxide ore reserves were depleted after approximately two millennia of mining, and that the beginning of the Bronze Age in the Balkans corresponded to the acquisition of pyrotechnology which allowed for the extraction of metals from sulfide minerals and the resumption of copper mining activity in the region.

Fluid inclusion gas chemistry as a potential minerals exploration tool: Case studies from Creede, CO, Jerritt Canyon, NV, Coeur d'Alene district, ID and MT, southern Alaska mesothermal veins, and mid-continent MVT's

USGS Publications Warehouse

Landis, G.P.; Hofstra, A.H.

1991-01-01

Recent advances in instrumentation now permit quantitative analysis of gas species from individual fluid inclusions. Fluid inclusion gas data can be applied to minerals exploration empirically to establish chemical (gas composition) signatures of the ore fluids, and conceptually through the development of genetic models of ore formation from a framework of integrated geologic, geochemical, and isotopic investigations. Case studies of fluid inclusion gas chemistry from ore deposits representing a spectrum of ore-forming processes and environments are presented to illustrate both the empirical and conceptual approaches. We consider epithermal silver-gold deposits of Creede, Colorado, Carlin-type sediment-hosted disseminated gold deposits of Jerritt Canyon, Nevada, metamorphic silver-base-metal veins of the Coeur d'Alene district, Idaho and Montana, gold-quartz veins in accreted terranes of southern Alaska, and the mid-continent base-metal sulfide deposits of Mississippi Valley-Type (MVT's). Variations in gas chemistry determine the redox state of the ore fluids, provide compositional input for gas geothermometers, characterize ore fluid chemistry (e.g., CH4CO2, H2SSO2, CO2/H2S, organic-rich fluids, gas-rich and gas-poor fluids), identify magmatic, meteoric, metamorphic, shallow and deep basin fluids in ore systems, locate upwelling plumes of magmatic-derived volatiles, zones of boiling and volatile separation, interfaces between contrasting fluids, and important zones of fluid mixing. Present techniques are immediately applicable to exploration programsas empirical studies that monitor fluid inclusion gas threshold concentration levels, presence or absence of certain gases, or changes in gas ratios. We suggest that the greater contribution of fluid inclusion gas analysis is in the integrated and comprehensive chemical dimension that gas data impart to genetic models, and in the exploration concepts based on processes and environments of ore formation derived from these genetic models. ?? 1991.

Enrichment Wastes' Processing of Manganiferous Ores with the Use of Mechanochemical Methods

ERIC Educational Resources Information Center

Kubekova, Sholpan N.; Kapralova, Viktoria I.; Ibraimova, Gulnur T.; Batyrbayeva, Aigul A.

2016-01-01

The aim of the research is the study of the chemical and phase composition of enrichment wastes of manganiferous ore in Ushkatyn-III deposit and the synthesis of new materials by mechanochemical activation and subsequent heat treatment of the mechanical activation products. The use of XFA, infrared spectroscopy and electron probe microanalysis…

Fractional crystallization-induced variations in sulfides from the Noril’sk-Talnakh mining district (polar Siberia, Russia)

USGS Publications Warehouse

Duran, C.J.; Barnes, S-J.; Pleše, P.; Prašek, M. Kudrna; Zientek, Michael L.; Pagé, P.

2017-01-01

The distribution of platinum-group elements (PGE) within zoned magmatic ore bodies has been extensively studied and appears to be controlled by the partitioning behavior of the PGE during fractional crystallization of magmatic sulfide liquids. However, other chalcophile elements, especially TABS (Te, As, Bi, Sb, and Sn) have been neglected despite their critical role in forming platinum-group minerals (PGM). TABS are volatile trace elements that are considered to be mobile so investigating their primary distribution may be challenging in magmatic ore bodies that have been somewhat altered. Magmatic sulfide ore bodies from the Noril’sk-Talnakh mining district (polar Siberia, Russia) offer an exceptional opportunity to investigate the behavior of TABS during fractional crystallization of sulfide liquids and PGM formation as the primary features of the ore bodies have been relatively well preserved. In this study, new petrographic (2D and 3D) and whole-rock geochemical data from Cu-poor to Cu-rich sulfide ores of the Noril’sk-Talnakh mining district are integrated with published data to consider the role of fractional crystallization in generating mineralogical and geochemical variations across the different ore types (disseminated to massive). Despite textural variations in Cu-rich massive sulfides (lenses, veins, and breccias), these sulfides have similar chemical compositions, which suggests that Cu-rich veins and breccias formed from fractionated sulfide liquids that were injected into the surrounding rocks. Numerical modeling using the median disseminated sulfide composition as the initial sulfide liquid composition and recent DMSS/liq and DISS/liq predicts the compositional variations observed in the massive sulfides, especially in terms of Pt, Pd, and TABS. Therefore, distribution of these elements in the massive sulfides was likely controlled by their partitioning behavior during sulfide liquid fractional crystallization, prior to PGM formation. Our observations indicate that in the Cu-poor massive sulfides the PGM formed as the result of exsolution from sulfide minerals whereas in the Cu-rich massive sulfides the PGM formed by crystallization from late-stage fractionated sulfide liquids. We suggest that the significant amount of Sn-bearing PGM may be related to crustal contamination from granodiorite, whereas As, Bi, Te, and Sb were likely added to the magma along with S from sedimentary rocks. Large PGM that are scarce and randomly distributed may account for most of the whole-rock Pt budget. Based on our results, we propose a holistic genetic model for the formation of the magmatic sulfide ore bodies of the Noril’sk-Talnakh mining district.

Physicochemical formation conditions of silver sulfoselenides at the Rogovik deposit, Northeastern Russia

NASA Astrophysics Data System (ADS)

Zhuravkova, T. V.; Palyanova, G. A.; Kravtsova, R. G.

2015-07-01

The chemical compositions of acanthite, naumannite, and associated ore minerals have been studied from the samples of polychronous Au-Ag ores at the Rogovik deposit. The following admixtures have been detected: S in naumannite (0-2.9 wt %), Se in acanthite (0-7.45 wt %), argyrodite (~4.8 wt %), and galena (~3.1 wt %), and Fe in sphalerite (~1.2 wt %). The physicochemical parameters of ore formation have been reconstructed on the basis of mineralogical and geochemical data and thermodynamic calculations. Eh-pH (25°C, 1 bar), log fO2-pH, log fS2- T, log fSe2- T, and log fS2-log fSe2 (100-300°C, 1-300 bars) diagrams for the Ag-S-Se-H2O system with the stability fields of Ag sulfoselenides Ag2S1- x Se x of various composition (step x = 0.25, where 0 ≤ x ≤ 1) have been calculated for the first time. It has been established that Ag sulfoselenides of the naumannite series from polychronous ores of the Rogovik deposit precipitated below 70-133°C under reductive conditions (log fO2 =-65…-50) from near-neutral solutions containing elevated Se and relatively lowered S. It has been established that Ag sulfoselenides of acanthite series were formed later then naumannite but in the same range of log fO2 values at temperatures below 110-177°C from solutions with high S concentration and relatively lowered concentration of Se. The complex composition of the studied Au-Ag ores, whose characteristic feature is extremely variable mineralogy, is confirmed.

The indirect electrochemical refining of lunar ores

NASA Technical Reports Server (NTRS)

Semkow, Krystyna W.; Sammells, Anthony F.

1987-01-01

Recent work performed on an electrolytic cell is reported which addresses the implicit limitations in various approaches to refining lunar ores. The cell uses an oxygen vacancy conducting stabilized zirconia solid electrolyte to effect separation between a molten salt catholyte compartment where alkali metals are deposited, and an oxygen-evolving anode of composition La(0.89)Sr(0.1)MnO3. The cell configuration is shown and discussed along with a polarization curve and a steady-state current-voltage curve. In a practical cell, cathodically deposited liquid lithium would be continuously removed from the electrolytic cell and used as a valuable reducing agent for ore refining under lunar conditions. Oxygen would be indirectly electrochemically extracted from lunar ores for breathing purposes.

The formation of cobalt-bearing ferromanganese crusts under fluid destruction of silicate matter

NASA Astrophysics Data System (ADS)

Maksimov, S. O.; Safronov, P. P.

2016-02-01

The processes of fluid destruction of various silicate rocks under diffusion of flows of compressed gases (mainly carbonaceous) were studied. The gas condensate nature was ascertained for the forming alumoslilicate and ore (cobalt-iron-manganese hydroxide) substances produced under this fluid destruction in the forms of microcrusts and microconcretions. The ore condensates contained in high concentrations the typomorphic elements of oceanic ferromanganese formations (Mn, Co, Ni, Cu, Pb, Ce, and Pt). The elemental composition of the ore oxide substance formed under the destruction of various silicate matrices exhibits a definite degree of endemism with prevalence of the Co-Mn association. The pronounced concentration of barium is related to the substantially carbonaceous composition of the fluid systems. A cerium paradox is revealed: Ce3+ is oxidized into Ce4+ and absorbed by ferromanganese hydrogel and the minimum of cerium appears in rare-earth phosphates.

Manganese and ferromanganese ores from different tectonic settings in the NW Himalayas, Pakistan

NASA Astrophysics Data System (ADS)

Tahir Shah, Mohammad; Moon, Charles J.

2007-02-01

In Pakistan manganese and ferromanganese ores have been reported from the Hazara area of North West Frontier Province, Waziristan agencies in the Federally Administered Tribal Areas and the Lasbela-Khuzdar regions of Baluchistan. This study is focused on comparison of mineralogy and geochemistry of the continental ferromanganese ores of Hazara and the ophiolitic manganese ores of the Waziristan area of Pakistan. In the Hazara area, ferromanganese ores occur at Kakul, Galdanian and Chura Gali, near Abbottabad, within the Hazira Formation of the Kalachitta-Margala thrust belt of the NW Himalayas of the Indo-Pakistan Plate. The Cambrian Hazira Formation is composed of reddish-brown ferruginous siltstone, with variable amounts of clay, shale, ferromanganese ores, phosphorite and barite. In Waziristan, manganese ores occur at Shuidar, Mohammad Khel and Saidgi, within the Waziristan ophiolite complex, on the western margin of the Indo-Pakistan Plate in NW Pakistan. These banded and massive ores are hosted by metachert and overlie metavolcanics. The ferromanganese ores of the Hazara area contain variable amount of bixbyite, partridgeite, hollandite, pyrolusite and braunite. Bixbyite and partridgeite are the dominant Mn-bearing phases. Hematite dominates in Fe-rich ores. Gangue minerals are iron-rich clay, alumino-phosphate minerals, apatite, barite and glauconite are present in variable amounts, in both Fe-rich and Mn-rich varieties. The texture of the ore phases indicates greenschist facies metamorphism. The Waziristan ores are composed of braunite, with minor pyrolusite and hollandite. Hematite occurs as an additional minor phase in the Fe-rich ores of the Shuidar area. The only silicate phase in these ores is cryptocrystalline quartz. The chemical composition of the ferromanganese ores in Hazara suggests that the Mn-Fe was contributed by both hydrogenous and hydrothermal sources, while the manganese ores of Waziristan originated only from a hydrothermal source. It is suggested that the Fe-Mn ores of the Hazara area originated from a mixed hydrothermal-hydrogenetic source in shallow water in a ontinental shelf environment due to the transgression and regression of the sea, while the Mn ores of Waziristan were formed at sea-floor spreading centers within the Neo-Tethys Ocean, and were later obducted as part of the Waziristan ophiolite complex.

Sulfur Isotopic Composition of Sulfides in Skarn and Vein Mineralization of the Dal'negorsk Ore Region (Primorye)

NASA Astrophysics Data System (ADS)

Rogulina, L. I.; Moiseenko, V. G.; Odarichenko, E. G.; Voropayeva, E. N.

2018-03-01

The S isotopic composition in the ore-forming minerals galena and sphalerite was studied in different Ag-Pb-Zn deposits of the region. It was pointed out that the δ34S modal values range from-1.2 to +6.7‰ in the minerals with a positive value for the skarn mineralization. In the flyschoid formation, the vein-type mineralization is characterized by negative and positive values. The narrow range of δ34S values indicates the marginal-continental type of the mineralization and the multiple origins of its sources.

Sedimentary exhalative nickel-molybdenum ores in south China

USGS Publications Warehouse

Lott, D.A.; Coveney, R.M.; Murowchick, J.B.; Grauch, R.I.

1999-01-01

Unique bedded Ni-Mo ores hosted by black shales were discovered in localized paleobasins along the Yangzte platform of southern China in 1971. Textural evidence and radiometric dates imply ore formation during sedimentation of black shales that grade into readily combustible beds, termed stone coals, which contain 10 to 15 percent organic carbon. Studies of 427 fluid inclusions indicate extreme variation in hydrothermal brine salinities that were contained by Proterozoic dolostones underlying the ore zone in Hunan and Guizhou. Variations of fluid inclusion salinities, which range from 0.1 to 21.6 wt percent NaCl equiv, are attributed to differences in the compositions of brines in strata underlying the ore bed, complicated by the presence of seawater and dilute fluids that represent condensates of vapors generated by boiling of mineralizing fluids or Cambrian meteoric water. The complex processes of ore deposition led to scattered homogenization temperatures ranging from 100??to 187??C within the Hunan ore zone and from 65??to 183??C within the Guizhou ore zone. While living organisms probably did not directly accumulate metals in situ in sufficient amounts to explain the unusually high grades of the deposits, sulfur isotope ratios indicate that bacteria, now preserved as abundant microfossils, provided sufficient sulfide for the ores by reduction of seawater sulfate. Such microbiota may have depended on vent fluids and transported organic matter for key nutrients and are consistent with a sedex origin for the ores. Vent fluids interacted with organic remains, including rounded fragments of microbial mats that were likely transported to the site of ore deposition by the action of waves and bottom currents prior to replacement by ore minerals.

Phase change of iron ore reduction process using EFB as reducing agent at 900-1200°C

NASA Astrophysics Data System (ADS)

Purwanto, H.; Salleh, H. M.; Rozhan, A. N.; Mohamad, A. S.; Zakiyuddin, A.

2018-04-01

Treatment of low grade iron ore involved reduction of oxygen in iron oxide by using reductant such as carbon monoxide or hydrogen gas. Presently, carboneous materials such as coke/coal are widely used as a source to provide reducing gas, but some problem arises from this material as the gas can harm the environments. Therefore, empty fruit bunch biomass from oil palm becomes an alternative to replace the usage of coke/coal as their major composition is carbon and hydrogen. The idea of replacing coke with biomass will reduce the amount of carbon dioxide release as biomass is a carbon neutral and renewable source, and at the same time abundance of waste from oil palm industries can be overcome. Therefore, the aim of this research is to upgrade the low grade iron with reducibility more than 50% being used in iron and steel making. In this research, low grade iron ore are mixed together with EFB then is making into composite pellet before being reduced at certain parameter chosen. The variables involved in this research is composition EFB (10%, 30% and 50%), temperature (1000°C, 1100°C and 1200°C) and reduction time is fixed with 30 minutes. From the experiment conducted, the highest reducibility achieved is 76.37% at temperature 1200°C. While XRD analysis shows the existence of metallic iron phase started to form at 1000°C with composition of 30% of EFB. Meanwhile, from magnetization test show that at 1200°C the highest magnetic susceptibility is achieved as the dominance phase at 1200°C is metallic phase. Therefore it is an interesting alternative to replace coke with biomass for reducing agent in upgrading low grade iron into workable ores.

Mineralogical and geochemical features of the alteration processes of magmatic ores in the Beni Bousera ultramafic massif (north Morocco)

NASA Astrophysics Data System (ADS)

Hajjar, Zaineb; Gervilla, Fernando; Essaifi, Abderrahim; Wafik, Amina

2017-08-01

The Beni Bousera ultramafic massif (Internal Rif, Morocco) is characterized by the presence of two types of small-scale magmatic mineralizations (i) a mineralization consisting mainly of chromite and Ni arsenides associated to orthopyroxene and cordierite (Cr-Ni ores), and (ii) a mineralization mainly composed of magmatic Fe-Ni-Cu sulfides containing variable amounts of graphite and chromite associated to phlogopite, clinopyroxène and plagioclase (S-G ores). Theses ores underwent High-T (450-550 °C) and Low-T (150-300 °C) alteration processes. The High-T alteration processes are tentatively related to intrusion of leucogranite dykes. They are preserved in the Galaros Cr-Ni ore deposit where nickeline is partly dissolved and transformed to maucherite, and orthopyroxene alters to phlogopite. Ni and Co were mobilized to the fluid phase, rising up their availability and promoting their diffusion into chromite and phlogopite, which have significantly higher contents in Ni and Co in phlogopite-rich ores than in orthopyroxene- and nickeline-rich ones. The Low-T alteration processes are related to serpentinization/weathering spatially associated with a regional shear zone. They affected both the Cr-Ni and S-G ores. In the Cr-Ni ores, Ni-arsenides were completely leached out while chromite is fractured within a matrix of chlorite, vermiculite and Ni-rich serpentine. In S-G ores, the silicates were altered into amphibole, Fe-rich chlorite and pectolite in clinopyroxene- and plagioclase-bearing ores while sulfides were completely leached out in phlogopite-bearing ores where iron oxides and hydroxides, and Fe-rich vermiculite were deposited. Chromite composition is not affected by the Low-T alteration processes.

Application of the Geo-Anomaly Unit Concept in Quantitative Delineation and Assessment of Gold Ore Targets in Western Shandong Uplift Terrain, Eastern China

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

Chen Yongqing, E-mail: ydonglai@mail.cgs.gov.cn; Zhao Pengda; Chen Jianguo

2001-03-15

A number of large and giant ore deposits have been discovered within the relatively small areas of lithospheric structure anomalies, including various boundary zones of tectonic plates. The regions have become the well-known intercontinental ore-forming belts, such as the circum-Pacific gold-copper, copper-molybdenum, and tungsten-tin metallogenic belts. These belts are typical geological anomalous areas. An investigation into the hydrothermal ore deposits in different regions in the former Soviet Union illustrated that the geologic structures of ore fields of almost all major commercial deposits have distinct features compared with the neighboring areas. These areas with distinct features are defined as geo-anomalies. Amore » geo-anomaly refers to such a geologic body or a combination of bodies that their composition, texture-structure, and genesis are significantly different from those of their surroundings. A geo-anomaly unit (GU) is an area containing distinct features that can be delineated with integrated ore-forming information using computer techniques on the basis of the geo-anomaly concept. Herein, the GU concept is illustrated by a case study of delineating the gold ore targets in the western Shandong uplift terrain, eastern China. It includes: (1) analyses of gold ore-forming factors; (2) compilation of normalized regional geochemical map and extraction of geochemical anomalies; (3) compilation of gravitational and aeromagnetic tectonic skeleton map and extraction of gravitational and aeromagnetic anomalies; (4) extraction of circular and linear anomalies from remote-sensing Landsat TM images; (5) establishment of a geo-anomaly conceptual model associated with known gold mineralization; (6) establishment of gold ore-forming favorability by computing techniques; and (7) delineation and assessment of ore-forming units. The units with high favorability are suggested as ore targets.« less

REM-containing silicate concentrates

NASA Astrophysics Data System (ADS)

Pavlov, V. F.; Shabanova, O. V.; Pavlov, I. V.; Pavlov, M. V.; Shabanov, A. V.

2016-01-01

A new method of advanced complex processing of ores containing rare-earth elements (REE) is proposed to obtain porous X-ray amorphous aluminosilicate material with a stable chemical composition which concentrates oxides of rare-earth metals (REM). The ferromanganese oxide ores of Chuktukon deposit (Krasnoyarsk Region, RF) were used for the experiment. The obtained aluminosilicate material is appropriate for treatment with 5 - 15% solutions of mineral acids to leach REM.

Evolution of ore deposits on terrestrial planets

NASA Astrophysics Data System (ADS)

Burns, R. G.

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

Evolution of ore deposits on terrestrial planets

NASA Technical Reports Server (NTRS)

Burns, R. G.

1991-01-01

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

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

NASA Astrophysics Data System (ADS)

Yu, Zhangfa; Chen, Maohong; Zhao, Haijie

2015-05-01

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

Ore-fluid evolution at the Getchell Carlin-type gold deposit, Nevada, USA

USGS Publications Warehouse

Cline, J.S.; Hofstra, A.A.

2000-01-01

Minerals and fluid-inclusion populations were examined using petrography, microthermometry, quadrupole mass-spectrometer gas analyses and stable-isotope studies to characterize fluids responsible for gold mineralization at the Getchell Carlin-type gold deposit. The gold-ore assemblage at Getchell is superimposed on quartz-pyrite vein mineralization associated with a Late-Cretaceous granodiorite stock that intruded Lower-Paleozoic sedimentary rocks. The ore assemblage, of mid-Tertiary age, consists of disseminated arsenian pyrite that contains submicrometer gold, jasperoid quartz, and later fluorite and orpiment that fill fractures and vugs. Late ore-stage realgar and calcite enclose ore-stage minerals. Pre-ore quartz trapped fluids with a wide range of salinities (1 to 21 wt.% NaCl equivalent), gas compositions (H2O, CO2, and CH4), and temperatures (120 to >360??C). Oxygen- and hydrogen-isotope ratios indicate that pre-ore fluids likely had a magmatic source, and were associated with intrusion of the granodiorite stock and related dikes. Ore-stage jasperoid contains moderate salinity, aqueous fluid inclusions trapped at 180 to 220??C. Ore fluids contain minor CO2 and trace H2S that allowed the fluid to react with limestone host rocks and transport gold, respectively. Aqueous inclusions in fluorite indicate that fluid temperatures declined to ~175??C by the end of ore-stage mineralization. As the hydrothermal system collapsed, fluid temperatures declined to 155 to 115??C and realgar and calcite precipitated. Inclusion fluids in ore-stage minerals have high ??D(H2O) and ??18O(H2O) values that indicate that the fluid had a deep source, and had a metamorphic or magmatic origin, or both. Late ore-stage fluids extend to lower ??D(H2O) values, and have a wider range of ??18O(H2O) values suggesting dilution by variably exchanged meteoric waters. Results show that deeply sourced ore fluids rose along the Getchell fault system, where they dissolved carbonate wall rocks and deposited gold-enriched pyrite and jasperoid quartz. Gold and pyrite precipitated together as H2S in the ore fluids reacted with iron in the host rocks. As ore fluids mixed with local aquifer fluids, ore fluids became cooler and more dilute. Cooling caused precipitation of ore-stage fluorite and orpiment, and late ore-stage realgar. Phase separation and/or neutralization of the ore fluid during the waning stages of the hydrothermal ore system led to deposition of late ore-stage calcite.

Fluid inclusion geothermometry

USGS Publications Warehouse

Cunningham, C.G.

1977-01-01

Fluid inclusions trapped within crystals either during growth or at a later time provide many clues to the histories of rocks and ores. Estimates of fluid-inclusion homogenization temperature and density can be obtained using a petrographic microscope with thin sections, and they can be refined using heating and freezing stages. Fluid inclusion studies, used in conjunction with paragenetic studies, can provide direct data on the time and space variations of parameters such as temperature, pressure, density, and composition of fluids in geologic environments. Changes in these parameters directly affect the fugacity, composition, and pH of fluids, thus directly influencing localization of ore metals. ?? 1977 Ferdinand Enke Verlag Stuttgart.

Sources of Matter and Ore-Producing Fluid of the Tamunyer Gold-Sulfide Deposit (Northern Urals): Isotope Results

NASA Astrophysics Data System (ADS)

Zamyatina, D. A.; Murzin, V. V.

2018-02-01

The Tamunyer deposit is a typical example of gold-sulfide mineralization located in the lower lithologic-stratigraphic unit (S2-D1) of the Auerbach volcanic-plutonic belt. The latter comprises island-arc andesitic volcano-sediments, volcanics, and comagmatic intrusive formations. Carbonates have demonstrated intermediate values of δ13C between marine limestone and mantle. The quartz δ18O is in the range of 15.3-17.2‰. The δ34S of sulfides from the beresitized volcano-sedimentary rocks and ores varies widely from -7.5 to 12‰. The calculated isotope compositions of H2O, CO2, and H2S of the ore-bearing fluid imply two major sources of matter contributing to ore genesis: local rocks and foreign fluid. The ore-bearing fluid was formed by interaction and isotope equilibration between a deep magmatic fluid and marine carbonates (W/R 1), with the contribution of sulfur from the volcano-sedimentary rocks.

Feasibility of co-reduction roasting of a saprolitic laterite ore and waste red mud

NASA Astrophysics Data System (ADS)

Wang, Xiao-ping; Sun, Ti-chang; Kou, Jue; Li, Zhao-chun; Tian, Yu

2018-06-01

Large scale utilization is still an urgent problem for waste red mud with a high content of alkaline metal component in the future. Laterite ores especially the saprolitic laterite ore are one refractory nickel resource, the nickel and iron of which can be effectively recovered by direct reduction and magnetic separation. Alkaline metal salts were usually added to enhance reduction of laterite ores. The feasibility of co-reduction roasting of a saprolitic laterite ore and red mud was investigated. Results show that the red mud addition promoted the reduction of the saprolitic laterite ore and the iron ores in the red mud were co-reduced and recovered. By adding 35wt% red mud, the nickel grade and recovery were 4.90wt% and 95.25wt%, and the corresponding iron grade and total recovery were 71.00wt% and 93.77wt%, respectively. The X-ray diffraction (XRD), scanning electron microscopy, and energy dispersive spectroscopy (SEM-EDS) analysis results revealed that red mud addition was helpful to increase the liquid phase and ferronickel grain growth. The chemical compositions "CaO and Na2O" in the red mud replaced FeO to react with SiO2 and MgSiO3 to form augite.

Effect of basicity and reductant amount in the nickel pig iron (NPI) production from Indonesian limonite ore in submerged electric arc furnace (SAF)

NASA Astrophysics Data System (ADS)

Astuti, W.; Andika, R.; Nurjaman, F.

2018-01-01

The effect of basicity and reductant amount on the nickel and iron recovery of the nickel pig iron (NPI) production from Indonesian limonite ore was investigated in the experimental study using submerged electric arc furnace (SAF). Indonesian limonite ore used in this study originated from Sulawesi Island with the composition of Ni (1.26%) and Fe (43%). Metallurgical coke was applied as the reductant. This study showed that the the highest nickel and iron recovery as well as metal yield can be resulted from the basicity of 0.8 and reductant amount of 0.23 kg coke/kg limonite ore. Nickel content in the NPI produced was around 3 - 4%. It was concluded that this experiment can produce medium grade NPI.

Bioavailability and uptake of smelter emissions in freshwater zooplankton in northeastern Washington, USA lakes using Pb isotope analysis and trace metal concentrations.

PubMed

Child, A W; Moore, B C; Vervoort, J D; Beutel, M W

2018-07-01

The upper Columbia River and associated valley systems are highly contaminated with metal wastes from nearby smelting operations in Trail, British Columbia, Canada (Teck smelter), and to a lesser extent, Northport, Washington, USA (Le Roi smelter). Previous studies have investigated depositional patterns of airborne emissions from these smelters, and documented the Teck smelter as the primary metal contamination source. However, there is limited research directed at whether these contaminants are bioavailable to aquatic organisms. This study investigates whether smelter derived contaminants are bioavailable to freshwater zooplankton. Trace metal (Zn, Cd, As, Sb, Pb and Hg) concentrations and Pb isotope compositions of zooplankton and sediment were measured in lakes ranging from 17 to 144 km downwind of the Teck smelter. Pb isotopic compositions of historic ores used by both smelters are uniquely less radiogenic than local geologic formations, so when zooplankton assimilate substantial amounts of smelter derived metals their compositions deviate from local baseline compositions toward ore compositions. Sediment metal concentrations and Pb isotope compositions in sediment follow significant (p < 0.001) negative exponential and sigmoidal patterns, respectively, as distance from the Teck smelting operation increases. Zooplankton As, Cd, and Sb contents were related to distance from the Teck smelter (p < 0.05), and zooplankton Pb isotope compositions suggest As, Cd, Sb and Pb from historic and current smelter emissions are biologically available to zooplankton. Zooplankton from lakes within 86 km of the Teck facility display isotopic evidence that legacy ore pollution is biologically available for assimilation. However, without water column data our study is unable to determine if legacy contaminants are remobilized from lake sediments, or erosional pathways from the watershed. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Tracking hydrothermal alteration and mineralization in rock-forming and accessory minerals from the Lyon Mountain Granite and related iron oxide apatite (IOA) ores from the Adirondack Mountains, New York State

NASA Astrophysics Data System (ADS)

Buchanan, A.; Hanchar, J. M.; Steele-MacInnis, M. J.; Crowley, J. L.; Valley, P. M.; Fisher, C. M.; Fedo, C.; Piccoli, P. M.; Fournelle, J.

2012-12-01

The Lyon Mountain granite (LMG) is located in the northeastern Adirondack Mountains in New York State and hosts several low-titanium iron oxide apatite (IOA) ore deposits. The ores are predominately hosted by perthite bearing granite, which has been extensively altered to albite and microcline granite by Na and K metasomatism. This alteration results in several distinct groups of rocks that are dominated by either K or Na addition and a group composed of mixed Na and K addition. The different groups of altered perthite also lie on a trend suggestive of addition of Fe to each, consistent with a secondary mineralization origin. Previous work showed that the host rocks of the IOA ores have zircon with ~1150 Ma cores and 1060-1050 Ma rims and whole grains. This study aims to further constrain the timing of LMG emplacement, subsequent hydrothermal alteration, and Fe mineralization through geochemical analysis of the major, minor, and accessory phases and geochronology of accessory phases. SIMS analyses of zircon from several of the IOA ores reveal at least two periods of growth after LMG magmatism, at 1039 +/- 4.4 Ma and 1016 +/- 7 Ma to 1000 +/- 9 Ma. In situ EMPA and LA-ICPMS trace element analyses of the zircon rims and cores reveal that in two samples the zircon rims are enriched in rare earth elements (REE) compared to their cores, potentially pointing to a hydrothermal origin. Apatite has unusually high REE and Y concentrations (some total REE2O3 > 20 wt. % oxide and up to 8 wt. % oxide Y2O3), as does titanite, which allowed for the in situ analysis of Sm-Nd in apatite and titanite by LA-MC-ICP-MS. Initial Nd isotopic composition of both ore and host rock apatite and host rock titanite are consistent with published Adirondack initial Nd whole rock data, suggesting a local source for REE in these ores. EMPA and LA-ICPMS trace-element analyses of the major rock-forming minerals indicate that the feldspar have undergone Na-metasomatism and are depleted in REEs, perhaps signifying the "local source" and the mechanism of the REE enrichment in the LMG apatite in the IOA ores and host rocks. In contrast, the minor- and trace-element compositions of the other major rock-forming minerals (e.g., clinopyroxene and fayalite) as well as the zircon, and fluorite in the LMG have average igneous granitic trace- and minor-element compositions. To better understand the timing and origin of these post ~1050 Ma events, U-Pb ID-TIMS dating of apatite and titanite, and in situ LA-MC-ICPMS Sm-Nd analysis were done on the ore and host rock samples. Apatite dates range from 1050 to 850 Ma and titanite dates range from ~1015 to 970 Ma. There is significant age variation within samples and within grains. Titanite does not have sufficient spread for accurate Sm-Nd isochron dating and two ore-apatite samples have homogenous initial Nd isotopic and Sm-Nd elemental ratios, precluding calculation of Sm-Nd dates. A third ore sample shows a large spread in Sm-Nd and yields a Sm-Nd isochron date of ~850 Ma, in close agreement with U-Pb apatite dates. The Sm-Nd isochron and U-Pb apatite dates may reflect cooling recorded in these minerals or a younger hydrothermal mineralization event.

Mo isotope fractionation during hydrothermal evolution of porphyry Cu systems

NASA Astrophysics Data System (ADS)

Shafiei, Behnam; Shamanian, GholamHossein; Mathur, Ryan; Mirnejad, Hassan

2015-03-01

We present Mo isotope compositions of molybdenite types from three successive stages of ore deposition in several porphyry copper deposits of the Kerman region, Iran. The data provide new insights into controlling processes on Mo isotope fractionation during the hydrothermal evolution of porphyry systems. The Mo isotope compositions of 27 molybdenite samples show wide variations in δ97Mo ranging from -0.37 to +0.92 ‰. The data reveal that molybdenites in the early and transitional stages of mineralization (preferentially 2H polytypes; δ97Mo mean = 0.35 ‰) have higher δ97Mo values than late stage (mainly 3R polytypes; δ97Mo mean = 0.02 ‰) molybdenites. This trend suggests that fractionation of Mo isotopes occurred in high-temperature stages of mineralization and that hydrothermal systems generally evolve towards precipitation of molybdenite with lower δ97Mo values. Taking into account the genetic models proposed for porphyry Cu deposits along with the temperature-dependent fractionation of Mo isotope ratios, it is proposed that large variations of Mo isotopes in the early and the transitional stages of ore deposition could be controlled by the separation of the immiscible ore-forming fluid phases with different density, pH, and ƒO2 properties (i.e., brine and vapor). The fractionation of Mo isotopes during fluid boiling and Rayleigh distillation processes likely dominates the Mo isotope budget of the remaining ore-forming fluids for the late stage of mineralization. The lower δ97Mo values in the late stage of mineralization can be explained by depletion of the late ore-forming hydrothermal solutions in 97Mo, as these fluids have moved to considerable distance from the source. Finally, the relationship observed between MoS2 polytypes (2H and 3R) and their Mo isotopic compositions can be explained by the molecular vibration theory, in which heavier isotopes are preferentially partitioned into denser primary 2H MoS2 crystals.

Genesis of the Permian karstic Pingguo bauxite deposit, western Guangxi, China

NASA Astrophysics Data System (ADS)

Liu, Xuefei; Wang, Qingfei; Zhang, Qizuan; Yang, Shujuan; Liang, Yayun; Zhang, Ying; Li, Yan; Guan, Tao

2017-10-01

More than 0.5 billion tons of late Permian bauxite overlies the karstic topography of the Maokou Formation of western Guangxi in China. Here, we provide new mineralogical, geochemical, Sr-Nd-Pb isotopic, and pyrite S isotope and trace element compositional data for the Pingguo bauxite deposit, aiming to further our understanding of the genesis of Permian bauxite. The Pingguo bauxite contains three distinct layers: a lower layer dominated by ferric clay or weathered iron ore, a middle layer of cryptocrystalline and oolitic bauxite ore, and an upper layer dominated by argillaceous bauxite. The bauxite ore is mainly diaspore, pyrite, chamosite, and anatase, whereas the argillaceous bauxite contains diaspore, kaolinite, pyrophyllite, pyrite, and anatase. Two types of pyrite have been identified within the bauxite: fine-grained and framboidal pyrite (Py1) occurring in aggregates and coarse-grained and euhedral pyrite (Py2). Py1 is enriched in trace elements and is thought to have a diagenetic origin, whereas Py2 is deficient in trace elements and is considered to have formed by later recrystallization. The S isotopic composition of pyrite (-34.11 to -18.91‰) and visible ovoid microorganisms within the bauxite provide evidences of microbial activity during bauxite formation. The Sr-Nd-Pb isotopic composition of the bauxite indicates that these ores were generated by the weathering of basalts belonging to the Emeishan Large Igneous Province (LIP) and limestones of the Maokou Formation. Microorganisms were likely to have enhanced the dissolution and weathering of the parent rock and facilitated the precipitation of diaspore under near-surface conditions.

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

USGS Publications Warehouse

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

1979-01-01

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

Iron isotope behavior during fluid/rock interaction in K-feldspar alteration zone - A model for pyrite in gold deposits from the Jiaodong Peninsula, East China

NASA Astrophysics Data System (ADS)

Zhu, Zhi-Yong; Jiang, Shao-Yong; Mathur, Ryan; Cook, Nigel J.; Yang, Tao; Wang, Meng; Ma, Liang; Ciobanu, Cristiana L.

2018-02-01

Mechanisms for Fe isotope fractionation in hydrothermal mineral deposits and in zones of associated K-feldspar alteration remain poorly constrained. We have analyzed a suite of bulk samples consisting of granite displaying K-feldspar alteration, Precambrian metamorphic rocks, and pyrite from gold deposits of the Jiaodong Peninsula, East China, by multi-collector inductively-coupled plasma mass spectrometry. Pyrites from disseminated (J-type) ores show a δ56Fe variation from +0.01 to +0.64‰, overlapping with the signature of the host granites (+0.08 to +0.39‰). In contrast, pyrites from quartz veins (L-type ores) show a wide range of Fe-isotopic composition from -0.78 to +0.79‰. Negative values are never seen in the J-type pyrites. The Fe isotope signature of the host granite with K-feldspar alteration is significantly heavier than that of the bulk silicate Earth. The Fe isotopic compositions of Precambrian metamorphic rocks across the district display a narrow range between -0.16‰ and +0.19‰, which is similar to most terrestrial rocks. Concentrations of major and trace elements in bulk samples were also determined, so as to evaluate any correlation between Fe isotope composition and degree of alteration. We note that during progressive K-feldspar alteration to rocks containing >70 wt% SiO2, >75 ppm Rb, and <1.2 wt% total Fe2O3, the Fe isotope composition of the granite changes systematically. The Fe isotope signature becomes heavier as the degree of alteration increases. The extremely light Fe isotopic compositions in L-type gold deposits may be explained by Rayleigh fractionation during pyrite precipitation in an open fracture system. We note that the sulfur isotopic compositions of pyrite in the two types of ores are also different. Pyrite from J-type ores has a systematically 3.5‰-higher δ34S value (11.2‰) than those of pyrite from the L-type ores (7.7‰). There is, however, no correlation between Fe and S isotope signatures. The isotopic fractionation of sulfur is used to constrain a change in the fO2 of the hydrothermal fluids from which pyrite precipitated. This work demonstrates that the Fe isotope composition of pyrite displays a significant response to the process of pyrite precipitation in hydrothermal systems, and that systematic fractionation of iron isotopes occurs during fluid/rock reaction in the K-feldspar alteration zone of the Linglong granite. The implications of the results are that processes of mineralization and associated fluid-rock interaction, which are ubiquitously observed in porphyry-style Cu-Au-Mo and other hydrothermal deposits, may be readily traceable using Fe isotopes.

Mineralogy and trace element geochemistry of the Co- and Cu-bearing sulfides from the Shilu Fe-Co-Cu ore district in Hainan Province of South China

NASA Astrophysics Data System (ADS)

Wang, Zhilin; Xu, Deru; Zhang, Zhaochong; Zou, Fenghui; Wang, Li; Yu, Liangliang; Hu, Mingyue

2015-12-01

Hosted within the metamorphosed, neritic siliciclastic rocks and sedimentary carbonates of the Proterozoic Shilu Group, the Shilu Fe-Co-Cu ore district in Hainan Province of South China comprises the upper Fe- and the lower Co-Cu ore layers. Combined with the field observation, the mineralogical and geochemical studies of sulfides using electron microprobe and laser ablation ICP-MS analyses recognized three types of Co-Cu ores. Type I is represented by massive ores and mainly comprises the first generation of pyrite (PyI) which occurred either as recrystallized, subhedral to euhedral microcrystal aggregates (PyIa) or as elongated, fine-grained euhedral grains (PyIb) with an orientated alignment parallel to S1 foliation. Type II is banded, disseminated and brecciated ores, and composed of the second generation of pyrite (PyII) which displays internal rhythmic growth zoning, the first generations of chalcopyrite (CcpI) and pyrrhotite (PoI), and associated Co-(Ni)-(As)-sulfide minerals. Type III occurring as veins or veinlets mainly consists of the third generation of pyrite (PyIII) and the second generations of chalcopyrite (CcpII) and pyrrhotite (PoII), of which PyIII appears as subhedral to euhedrall grains or as rims of composite pyrite. The moderate Co and As, and high Ni contents as well as the low Co/Ni ratios (∼2-5) in PyI indicate a sedimentary-metamorphic origin for Type I ores. The higher Co, Ni and As concentrations in PyIb relative to PyIa likely was related to an inhomogeneous deformation-metamorphism. The highest Co (av. 51,195 ppm) in PyII and Ni (av. 3374 ppm) in PoI most likely were linked to the preferred incorporation of Co into pyrite and Ni into pyrrhotite. Combined with the high Ag concentrations in CcpI (av. 266 ppm) and PyII (av. 13.32 ppm), the high Co/Ni ratios in PyII (av. 1241) suggest the derivation of Type II ores from a Co-Cu-Ni-Ag-rich hydrothermal fluid. Further, up to 9 wt.% Co concentrations in PyII show a temperature condition of 310-400 °C. In contrast, the depletion of trace elements in CcpII and PyIII, and the lower Co/Ni ratios (av. 46) in PyIII suggest a Co-poor but Cu-bearing hydrothermal fluid for origin of Type III ores. The complex texture and chemical composition of sulfides combined with previous work confirm a four-stage metallogenesis for the Shilu Co-Cu ores. From early to late, these include: (1) the ca. 1075-880 Ma deposition of the primary Co-Cu ore source beds which most likely were derived from submarine, metalliferous hydrothermal fluids, (2) the syn-structural metamorphism which led to Type I ores due to the South China Caledonian Orogeny, (3) the first stage of hydrothermalism which produced Type II ores and most likely was associated with Indosinian magmatism, and (4) the second stage of hydrothermalism which yielded Type III ores and likely was related to Yanshanian magmatism. The first stage of hydrothermalism was considered to be significant for the Co-Cu enrichment. The Shilu Co-Cu ores thus are better attributed to a BIF origin, but greatly reworked and enriched by late structural deformation and hydrothermal activities.

Geochemistry of the Nsuta Mn deposit in Ghana: Implications for the Paleoproterozoic atmosphere and ocean chemistry

NASA Astrophysics Data System (ADS)

Goto, K. T.; Ito, T.; Suzuki, K.; Kashiwabara, T.; Takaya, Y.; Shimoda, G.; Nozaki, T.; Kiyokawa, S.; Tetteh, G. M.; Nyame, F. K.

2013-12-01

Oxygenation of the atmosphere and oceans has influenced the evolution of ocean chemistry and diversification of early life. A number of large manganese (Mn) deposits are distributed in the Paleoproterozoic sedimentary successions that were formed during the great oxidation event (GOE) around 2.4-2.2 Ga (Meynard, 2010). Due to the high redox potential of Mn, occurrences of Mn deposits have been regarded as important evidence for a highly oxidized environment during the Paleoproterozoic (Kirschvink et al., 2000). Furthermore, because Mn oxides strongly adsorb various elements, including bioessential elements such as Mo, formation of large Mn deposits may have affected the seawater chemical composition and ecology during the Paleoproterozoic. However, the genesis of each Mn deposit is poorly constrained, and the relationships among the formation of Mn deposits, the evolution of atmospheric and ocean chemistry, and the diversification of early life are still ambiguous. In this study, we report the Re-Os isotope compositions, rare earth element (REE) compositions, and abundance of manganophile elements in the Mn carbonate ore and host sedimentary rock samples collected from the Nsuta Mn deposit of the Birimian Supergroup, Ghana. The Nsuta deposit is one of the largest Paleoproterozoic Mn deposits, although its genesis remains controversial (Melcher et al., 1995; Mucke et al., 1999). The composite Re-Os isochron age (2149 × 130 Ma) of the Mn carbonate and sedimentary rock samples was consistent with the depositional age of the sedimentary rocks (~2.2 Ga) presumed from the U-Pb zircon age of volcanic rocks (Hirdes and Davis, 1998), suggesting that the timing of Mn ore deposition was almost equivalent to the host rock sedimentation. The PAAS-normalized REE pattern showed a positive Eu anomaly in all samples and a positive Ce anomaly only in the Mn carbonate ore. These REE patterns indicate the possible contribution of Eu-enriched fluids derived from hydrothermal activity and Ce enrichment due to the oxidation of Ce(III) by Mn(IV) during an ore formation. Among the manganophile elements, merely Mo is enriched in the Mn carbonate ore compared with the host sedimentary rocks. The profile of manganophile elements was similar to that of modern hydrothermal Mn oxide (Kuhn et al., 2003), although the exact Mo concentration was much lower. These geochemical lines of evidence provide the following plausible genetic model for the Nsuta deposits: (1) Mn(II) was derived from hydrothermal vents, (2) Mn(II) was oxidized to Mn(IV) oxide by the oxygenated seawater, (3) the precipitation of Mn oxide is almost concurrent with the deposition of the host sedimentary rocks, (4) Mn oxide was diagenetically transformed to be a Mn carbonate ore. The geochemical features of the Nsuta deposits suggest that, as in the present oxic oceans, Mn oxide was a potential sink for several trace elements in the Paleoproterozoic oceans. The low-Mo concentration in the Mn carbonate ore probably reflects the large difference between the chemical compositions of Paleoproterozoic and present seawater, implying the prevalence of reduced marine conditions even during the GOE (Scott et al., 2008)

Thallium-rich pyrite ores from the Apuan Alps, Tuscany, Italy:constraints for their origin and environmental concerns

NASA Astrophysics Data System (ADS)

D'Orazio, Massimo; Biagioni, Cristian; Dini, Andrea; Vezzoni, Simone

2017-06-01

The southern sector of the Apuan Alps (AA) massif, Tuscany, Italy, is characterized by the occurrence of a series of baryte-pyrite-iron oxide orebodies whose Tl-rich nature was recognized only recently. The geochemistry of the pyrite ore was investigated through inductively coupled plasma mass spectrometry. In addition, lead isotope data for selected pyrite ores from AA were collected. Pyrite ores are characterized by a complex geochemistry, with high concentrations of Tl (up to 1100 μg/g) coupled with high As and Sb contents; the Co/Ni ratio is always <1. Geochemical data of pyrite and marcasite ore samples from other mining districts of Tuscany have been collected in order to compare them with those from the AA. These samples usually have very low Tl content (less than 2 μg/g) and high to very high Co/Ni and As/Sb ratios. Only some samples from the Sb-Hg ore deposits showed very high Tl concentrations (up to 3900 μg/g). Another difference is related to the lead isotope composition, with pyrite ores from AA markedly less radiogenic than those from the other deposits from Tuscany. Geochemical data of pyrite ores from AA give new insights on the genesis of the baryte-pyrite-iron oxide orebodies, relating their formation to low-temperature hydrothermal systems active during early Paleozoic; in addition, these data play a fundamental role in assessing the environmental impact of these deposits.

Titanium minerals of placer deposits as a source for new materials

NASA Astrophysics Data System (ADS)

Kotova, Olga; Ponaryadov, Alexey

2015-04-01

Heavy mineral deposits are a source of the economic important element titanium, which is contained in ilmenite and leucoxene. The mineral composition of placer titanium ore and localization pattern of ore minerals determine their processing and enriching technologies. New data on the mineralogy of titanium ores from modern coastal-marine placer in Stradbroke Island, Eastern Australia, and Pizhma paleoplacer in Middle Timan, Russia, and materials on their basis are presented. The samples were studied by the following methods: optical-mineralogical (stereomicroscope MBS-10, polarizing microscope POLAM L-311), semiquantitative x-ray phase analysis (x-ray difractometer X'Pert PRO MPD). Besides microprobe (VEGA 3 TESCAN) and x-ray fluorescent analysis (XRF-1800 Shimadzu) were used. By the mineralogical composition ores of the both deposits are complex: enriched by valuable minerals. Apart from main ore concentrates it is possible to obtain accompanying nonmetallic products. This will increase the efficiency of deposit exploitation. Ilmenite dominates in ore sands of Stradbroke Island, and leucoxene dominates in the ores of the Pizhma titanium deposit. Australian ilmenite and its altered varieties are mainly characterized by a very high MnO content (from 5.24 to 11.08 %). The irregular distribution of iron oxides, titanium and manganese in the altered ilmenite was shown in the paper. E.g., in the areas of substitution of ilmenite by pseudorutile the concentrations of the given elements are greatly various due to various ratios of basic components in each grain. Their ratios are equal in the area of rutile evolution. Moreover, the high content of gold, diamonds and also rare earth elements (REE) and rare metals (their forms are not determined) were studied. We found native copper on the surface of minerals composing titanium-bearing sandstones of the Pizhma placer. According to the technological features of rocks (density and magnetic) studied placers are close. The obtained results of physical studies, mineral composition features, morphostructural characteristics and degree of alteration of titanium minerals from the placers specify a high potential of physical methods of processing (gravitational and magnetic separation, flotation) and possible application of combined methods of processing. Production of pigment titanium dioxide for further production of titanium white, paper, plastics etc is the usual application area of titanium concentrates. Titanium dioxide of high chemical purity is used to produce optically transparent glass, fiber optics, electronics (iPad), piezoceramics, in medical and food industry. We designed photocatalysts based on leucoxene from Pizhma placer. The results showed that the photocatalysts based on rutile, synthesized from leucoxene from Pizhma deposit, can be applied to decay phenols in water.

Petrogenesis of Ore-Bearing and Ore-Barren Intermediate-Acid Intrusive Rocks from Jilongshan Au-Cu Skarn Deposit , the Middle-Lower Yangtze River Metallogenic Belt, Eastern China and their Geological Implications

NASA Astrophysics Data System (ADS)

Zhan, X.; Wei, J.; Chen, M.; Zhao, X.

2017-12-01

Jilongshan Au-Cu skarn deposit in Edong-Jiurui ore district , Middle-Lower Yangtze River Metallogenic Belt(MLYRB) , eastern China ,contains 44 t gold and 32 Mt of copper ores. The mineralization is dominated by massive skarn ores, most of which occurs along the contact zone between the lower Triassic dolomitic limestones and Jilongshan granodioritic intrusion. However, Baiguoshu pluton, no more than 1 km western, has been not found any mineralized occurrence with the same strata. The ore-bearing and ore-barren intrusive rocks are granodiorite porphyries, could not be identified by petrographic characters. Besides, Zircon U-Pb dating results demonstrate that Jilongshan and Baiguoshu intrusion emplaced at 140 ± 1Ma and 141 ± 1 Ma respectively, coeval with the Early Cretaceous magmatism in Edong-Jiurui area. Elements geochemistry present that they are both characterized by high Al2O3, rich Na2O (Na2O/K2O>1.0), enrichment of LILE (Rb, Ba, K, Sr) and depletion of HFSE (Nb, Ta), and weak negative Eu anomalies, which suggest they may be originated from partial melting of enriched mantle and associated with crust-mantle interaction ,evidenced by the Sr-Nd-Hf isotopic composition as well. Although the two are partly geochemically similar with each other, they have some obvious differences. The former have higher K2O and Y, Yb ,lower MgO, and Cr, Ni contents, and more obvious differentiation degree between light and heavy REEs with (La/Yb)N=10.55-15.95 than the latter with (La/Yb)N=8.67-10.47. It is indicated that the magmas of the Jilongshan intrusive rocks were probably derived from deeper source than that of the Baiguoshu, also supported by mineralogical data of biotite. In addition, Jilongshan intrusive rocks have a relatively higher initial Nd (ɛNd (t) = -8.2 - -9.4) and Sr ((87Sr/86Sr)i=0.70822-0.70897) isotopic composition than Baiguoshu (-9.2 - -9.7 and 0.70855-0.70881), as same as Lu-Hf isotopic composition. Therefore, combined with previous studies, we suggest that the Jilongshan granodiorite porphyry originated as partial melts of an enriched mantle source experienced more sufficient interaction with lower crust materials during magma ascent compared with Baiguoshu granodiorite porphyry, which may lead to Cu-Au enriched magmas, contributing to subsequent mineralization.

Stable isotope, chemical, and mineral compositions of the Middle Proterozoic Lijiaying Mn deposit, Shaanxi Province, China

USGS Publications Warehouse

Yeh, Hsueh-Wen; Hein, James R.; Ye, Jie; Fan, Delian

1999-01-01

The Lijiaying Mn deposit, located about 250 km southwest of Xian, is a high-quality ore characterized by low P and Fe contents and a mean Mn content of about 23%. The ore deposit occurs in shallow-water marine sedimentary rocks of probable Middle Proterozoic age. Carbonate minerals in the ore deposit include kutnahorite, calcite, Mn calcite, and Mg calcite. Carbon (−0.4 to −4.0‰) and oxygen (−3.7 to −12.9‰) isotopes show that, with a few exceptions, those carbonate minerals are not pristine low-temperature marine precipitates. All samples are depleted in rare earth elements (REEs) relative to shale and have negative Eu and positive Ce anomalies on chondrite-normalized plots. The Fe/Mn ratios of representative ore samples range from about 0.034 to <0.008 and P/Mn from 0.0023 to <0.001. Based on mineralogical data, the low ends of those ranges of ratios are probably close to ratios for the pure Mn minerals. Manganese contents have a strong positive correlation with Ce anomaly values and a moderate correlation with total REE contents. Compositional data indicate that kutnahorite is a metamorphic mineral and that most calcites formed as low-temperature marine carbonates that were subsequently metamorphosed. The braunite ore precursor mineral was probably a Mn oxyhydroxide, similar to those that formed on the deep ocean-floor during the Cenozoic. Because the Lijiaying precursor mineral formed in a shallow-water marine environment, the atmospheric oxygen content during the Middle Proterozoic may have been lower than it has been during the Cenozoic.

How metalliferous brines line Mexican epithermal veins with silver

PubMed Central

Wilkinson, Jamie J.; Simmons, Stuart F.; Stoffell, Barry

2013-01-01

We determined the composition of ~30-m.y.-old solutions extracted from fluid inclusions in one of the world's largest and richest silver ore deposits at Fresnillo, Mexico. Silver concentrations average 14 ppm and have a maximum of 27 ppm. The highest silver, lead and zinc concentrations correlate with salinity, consistent with transport by chloro-complexes and confirming the importance of brines in ore formation. The temporal distribution of these fluids within the veins suggests mineralization occurred episodically when they were injected into a fracture system dominated by low salinity, metal-poor fluids. Mass balance shows that a modest volume of brine, most likely of magmatic origin, is sufficient to supply the metal found in large Mexican silver deposits. The results suggest that ancient epithermal ore-forming events may involve fluid packets not captured in modern geothermal sampling and that giant ore deposits can form rapidly from small volumes of metal-rich fluid. PMID:23792776

Simulation of geochemical processes responsible for the formation of the Zhezqazghan deposit

NASA Astrophysics Data System (ADS)

Ryzhenko, B. N.; Cherkasova, E. V.

2014-05-01

Physicochemical computer simulation of water-rock systems at a temperature of 25-150°C and under a pressure of up to 600 bar has been carried out for quantitative description of the mineralization formation conditions at sandstone- and shale-hosted copper deposits. The simulation is based on geological and geochemical information concerning the Zhezqazghan deposit and considers (i) a source of ore matter, (ii) composition of the fluid that transfers ore matter to the ore formation zone, and (iii) factors of ore concentration. It has been shown that extraction of copper from minerals of rocks and its accumulation in aqueous solution are optimal at a high mass ratio of rock to water (R/W > 10), Eh of +200 to -100 mV, and an obligatory content of chloride ions in the aqueous phase. The averaged ore-bearing fluid Cl95SO44//Ca50(Na + K)30Mg19 (eq %), pH ˜ 4, mineralization of up to 400 g/L, is formed by the interaction of red sandstone beds with a sedimentogenic brine (a product of metamorphism of seawater in carbonate rocks enriched in organic matter). The ore concentration proceeds in the course of cooling from 150 to 50°C during filtration of ore-bearing fluid through red sandstone beds in the rock-water system thermodynamically opened with respect to the reductive components.

Characterization of Sumbawa manganese ore and recovery of manganese sulfate as leaching products

NASA Astrophysics Data System (ADS)

Kusumaningrum, Retno; Rahmani, Siti Astari; Widayatno, Wahyu Bambang; Wismogroho, Agus Sukarto; Nugroho, Dwi Wahyu; Maulana, Syahrizal; Rochman, Nurul Taufiqu; Amal, M. Ikhlasul

2018-05-01

The aims of this research were to study the leaching process of manganese ore which originated from Sumbawa, Indonesia and its characterization. A high grade Indonesian manganese ore from Sumbawa, West of Nusa Tenggara was characterized by X-Ray Fluorescence (XRF). The result showed composition of 78.8 % Mn, 17.77% Fe and the rest were trace elements such as Si, Co, Ti, Zn, V and Zr contents. X-Ray Diffraction analysis showed that the manganese ore was consisted of pyrolusite (MnO2), rhodonite (MnSiO3), rhodochrosite (MnCO3) and hematite (Fe2O3). Manganese ore was also analyzed by thermal analysis to observe their thermal decomposition character. In this study, sulphuric acid (H2SO4, 6 M) was deployed as leaching agent. The leaching process was performed at 90 °C for two hours with the addition of NH4OH to control pH. Recovery percentage of leaching process yielded of 87 % Mn extracted. The crystallization process result at heating temperature of 200 °C was confirmed by XRD as manganese sulfate.

Bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance

NASA Astrophysics Data System (ADS)

Laskou, Magdalini; Economou-Eliopoulos, Maria

2013-08-01

The Parnassos-Ghiona bauxite deposit in Greece of karst type is the 11th largest bauxite producer in the world. The mineralogical, major and trace-element contents and δ18O, δ12C, δ34S isotopic compositions of bauxite ores from this deposit and associated limestone provide valuable evidence for their origin and biogeochemical processes resulting in the beneficiation of low grade bauxite ores. The organic matter as thin coal layers, overlying the bauxite deposits, within limestone itself (negative δ12C isotopic values) and the negative δ34S values in sulfides within bauxite ores point to the existence of the appropriate circumstances for Fe bio-leaching and bio-mineralization. Furthermore, a consortium of microorganisms of varying morphological forms (filament-like and spherical to lenticular at an average size of 2 μm), either as fossils or presently living and producing enzymes, is a powerful factor to catalyze the redox reactions, expedite the rates of metal extraction and provide alternative pathways for metal leaching processes resulting in the beneficiation of bauxite ore.

Kinetic study of nickel laterite reduction roasting by palm kernel shell charcoal

NASA Astrophysics Data System (ADS)

Sugiarto, E.; Putera, A. D. P.; Petrus, H. T. B. M.

2017-05-01

Demand to process nickel-bearing laterite ore increase as continuous depletion of high-grade nickel-bearing sulfide ore takes place. Due to its common nickel association with iron, processing nickel laterite ore into nickel pig iron (NPI) has been developed by some industries. However, to achieve satisfying nickel recoveries, the process needs massive high-grade metallurgical coke consumption. Concerning on the sustainability of coke supply and positive carbon emission, reduction of nickel laterite ore using biomass-based reductor was being studied.In this study, saprolitic nickel laterite ore was being reduced by palm kernel shell charcoal at several temperatures (800-1000 °C). Variation of biomass-laterite composition was also conducted to study the reduction mechanism. X-ray diffraction and gravimetry analysis were applied to justify the phenomenon and predict kinetic model of the reduction. Results of this study provide information that palm kernel shell charcoal has similar reducing result compared with the conventional method. Reduction, however, was carried out by carbon monoxide rather than solid carbon. Regarding kinetics, Ginstling-Brouhnstein kinetic model provides satisfying results to predict the reduction phenomenon.

Temporal Evolution of Volcanic and Plutonic Magmas Related to Porphyry Copper Ores Based on Zircon Geochemistry

NASA Astrophysics Data System (ADS)

Dilles, J. H.; Lee, R. G.; Wooden, J. L.; Koleszar, A. M.

2015-12-01

Porphyry Cu (Mo-Au) and epithermal Au-Ag ores are globally associated with shallow hydrous, strongly oxidized, and sulfur-rich arc intrusions. In many localities, long-lived magmatism includes evolution from early andesitic volcanic (v) and plutonic (p) rocks to later dacitic or rhyolitic compositions dominated by plutons. We compare zircon compositions from three igneous suites with different time spans: Yerington, USA (1 m.y., p>v), El Salvador, Chile (4 m.y., p>v), and Yanacocha, Peru (6 m.y., v>p). At Yerington granite dikes and ores formed in one event, at ES in 2 to 3 events spanning 3 m.y., and at Yanacocha in 6 events spanning 5 m.y. At both ES and Yanacocha, high-Al amphiboles likely crystallized at high temperature in the mid-crust and attest to deep magmas that periodically recharged the shallow chambers. At Yanacocha, these amphiboles contain anhydrite inclusions that require magmas were sulfur-rich and strongly oxidized (~NNO+2). The Ti-in-zircon geothermometer provides estimates of 920º to 620º C for zircon crystallization, and records both core to rim cooling and locally high temperature rim overgrowths. Ore-related silicic porphyries yield near-solidus crystallization temperatures of 750-650°C consistent with low zircon saturation temperatures. The latter zircons have large positive Ce/Ce* and small negative Eu/Eu*≥0.4 anomalies attesting to strongly oxidized conditions (Ballard et al., 2001), which we propose result from crystallization and SO2 loss to the magmatic-hydrothermal ore fluid (Dilles et al., 2015). The Hf, REE, Y, U, and Th contents of zircons are diverse in the magma suites, and Th/U vs Yb/Gd plots suggest a dominant role of crystal fractionation with lesser roles for both crustal contamination and mixing with high temperature deep-sourced mafic magma. Ce/Sm vs Yb/Gd plots suggest that magma REE contents at <900°C are dominated by early crystallization of hornblende and apatite, and late crystallization (~<780°C) of titanite. Magma mixing and crustal contamination are most evident in pre-ore magmas, whereas ore-forming intrusions at low temperatures are dominated by crystal fractionation. Thus, zircon provides evidence for cyclic crystallization and mafic recharge that enrich late silicic melts in incompatible ore components water, sulfur, chlorine and metals.

Environment of ore deposition in the Creede mining district, San Juan Mountains, Colorado: Part VI. Maximum duration for mineralization of the OH vein

USGS Publications Warehouse

Campbell, W.R.; Barton, P.B.

2005-01-01

The rate at which ore deposits form is one of the least well established parameters in all of economic geology. However, increased detail in sampling, improved technology of dating, and sophistication in modeling are reducing the uncertainties and establishing that ore formation, at least for the porphyry copper-skarn-epithermal base and precious metals deposit package, may take place in surprisingly brief intervals. This contribution applies another approach to examine the duration of mineralization. The degree to which compositional gradients within single crystals has flattened through solid-state diffusion offers a measure of the thermal dose (that is temperature combined with time) that the crystals have been subjected to since deposition. Here we examine the steepness of gradients in iron content within individual single sphalerite crystals from the epithermal silver-lead-zinc deposit in the OH vein at Creede, Colorado. Two initial textures are considered: growth-banded crystals and compositionally contrasting overgrowths that succeed crosscutting dissolution or fractured surfaces. The model used estimates the maximum possible time by assuming a perfectly sharp original compositional step, and it asks how long it would take at a known temperature for the gradient measured today to have formed. Applying the experimentally determined diffusion rates of Mizuta (1988a) to compositional gradients (ranging from 0.4-2.2 mol % FeS/??m) measured by the electron microprobe in 2-??m steps on banded sphalerite formed early in the paragenetic history yields a maximum duration of less than ???10,000 yr. Sphalerite from a solution unconformity in a position midway through the paragenetic sequence is indistinguishable from instantaneous deposition, supporting the conclusion of rapid ore formation. While this formation interval seems very brief, it is consistent with less well constrained estimates using entirely different criteria. ?? 2005 Society of Economic Geologists, Inc.

The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

NASA Astrophysics Data System (ADS)

Deditius, Artur P.; Reich, Martin; Kesler, Stephen E.; Utsunomiya, Satoshi; Chryssoulis, Stephen L.; Walshe, John; Ewing, Rodney C.

2014-09-01

The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ∼30 to ∼600 °C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ∼200 to ∼500 °C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and alteration by hydrothermal fluids. The second trend consists of pyrites from porphyry Cu and epithermal Au deposits, which are characterised by compositions that preserve the Au/As signature of mineralizing magmatic-hydrothermal fluids, confirming the role of this sulfide in controlling metal ratios in ore systems.

Barite-polymetallic mineralization of Zmeinogorsk ore district and some genetic aspects of its formation

NASA Astrophysics Data System (ADS)

Bestemianova, K. V.; Grinev, O. M.

2017-12-01

Zmeinogorsky ore district is located in the northwest part of Ore Altai megatrough, which has long-lasting history of its development and complicated geological structure. Within the ore district, which is the northwest part of the devonian Zmeinogorsk-Bystrushinsky trough, ore mineralization is associated with the system of northwest border faults and cross branch faults. There were four main stages and five phases of minerogenesis. The first stage is the stage of oregenesis beginning and quartz-chlorite-sericite wall-rock alteration rocks formation. Ore deposition and intense tectonics took place during the second stage. The third stage is the most longstanding and productive ore formation stage. There are five distinct minerogenesis phases within this stage. The fourth stage expressed in erosion development and supergene alteration of already formed ore bodies with oxidation zone formation. Main ore minerals are pyrite, chalcopyrite, sphalerite and galena. Minor minerals are tetrahedrite, bornite, tennantite and chalcocite. Precious metals minerals are acanthite, gold, electrum, gold and silver amalgams. Barren minerals are barite, quartz, calcite, gypsum. According to obtained data average isotopic composition of third stage sulphides is: pyrite -0,2‰, chalcopyrite 0‰, galena +0,5‰, sphalerite -1,2‰ for the first complex; chalcopyrite -1,9‰, galena -3,4‰, sphalerite -2,3‰, tetrahedrite -3,7‰ for the second complex; tennantite -12,8‰, bornite -8,9‰ for the third complex. Sulfur isotopic compoisiton variations indicate source inhomogeneity. Thus, there was dominant source change from mantle one in the beginning to crustal one in the end. Main oregenesis stages took place in the range of temperatures between 170 and 210°С and in the mineral-forming solutions salinity range between 3 and 10 wt % NaCl equiv.

Investigation of LANDSAT imagery on correlations between ore deposits and major shield structures in Finland

NASA Technical Reports Server (NTRS)

Tuominen, H. V. (Principal Investigator); Kuosmanen, V.

1977-01-01

The author has identified the following significant results. Several regional lineaments appear to correlate with the distribution of ore deposits and showings. Combined study of LANDSAT summer and winter mosaics and color composites of geological, geomorphological, and geophysical maps makes the correlation more perceptible. The revealed pattern of significant lineaments in northern Finland is fairly regular. The most significant lineaments seen in LANDSAT mosaics are not detectable in single images.

The isotopic composition of ore lead of the Creede mining district and vicinity, San Juan Mountains, Colorado: Text of a talk presented at the San Juan Mountains symposium to honor Thomas A. Steven; Rocky Mountain Section meeting of the Geological Society of America, May 2, 1987, Boulder, Colorado

USGS Publications Warehouse

Foley, N.K.; Barton, P.B.; Bethke, P.M.; Doe, B.R.

1988-01-01

Recent work allows us to extend the results of Doe et al. and to consider alternative processes to explain the widespread homogeneity and radiogenic nature of the ore lead: 1) David Matty (pers. commun., 1986) has shown that some minor volcanic units in the area have unusually radiogneic lead values; magmas comparable in composition to the units are a possible, though improbable, source of the ore lead. 2) The uniformity of the isotopic values of galenas may have resulted from homogenization during an extensive potassium-metasomatic event that predated the ores; this possibility is being tested in an on-going study of feldspars from metasomatized and unmetasomatized rocks. 3) Recent regional studies suggest the possibility of a prevolcanic, NNW-trending graben system filled by clastic sediments derived from the Precambrian basement, a process that would have an homogenizing effect on the lead isotopes. This interpretation implies importation, deep within the Creede hydrologic system, of fluids from remote sources. These alternatives show that the Pbisotope systematics may have a profound impact on the interpretation of the Creede hydrothermal system, and that further study is warranted.

Geochemistry and geochronology of ore-bearing and barren intrusions in the Luanchuan ore fields of East Qinling metallogenic belt, China: Diverse tectonic evolution and implications for mineral exploration

NASA Astrophysics Data System (ADS)

Xue, Fei; Wang, Gongwen; Santosh, M.; Yang, Fan; Shen, Zhiwei; Kong, Liang; Guo, Nana; Zhang, Xuhuang; Jia, Wenjuan

2018-05-01

The Luanchuan ore fields form part of the East Qinling metallogenic belt in central China. In this study, we compare two ore-bearing intrusions, the Shibaogou granitic pluton (SBG) and the Zhongyuku granitic pluton (ZYK), with the ore-barren Laojunshan intrusion (LJS) from the Luanchuan ore field. Geochemically, all the three intrusions are characterized by high-Si, high-K, and alkalis, together with moderate-ASI, exhibiting I-type granite features. The rocks, especially the ore-related plutons also show enrichment in LREEs. Mineral chemistry of biotite from the intrusions exhibits similar features of high Si and Mg, and low Al and Fe. Zircon grains from the ZYK intrusion yielded a U-Pb age of 149.6 ± 2.4 Ma. The zircon grains show εHf (t) values and two stage model ages (TDM2) in the range of -16.8 to -19.7 and 1998-2156 Ma respectively. The biotite composition and Hf isotopic data indicate that the magma was derived by re-melting of deep crustal material with minor input of mantle components. We evaluate the results to understand the physico-chemical conditions, petrogenesis, and tectonic setting, and their implications for mineral exploration. The ore-bearing plutons show wide ranges of temperature and oxygen fugacity, favoring Mo-W mineralization. In addition, estimates on pressure and depth of emplacement suggest that lower solidification pressure in a decompressional setting contributed to the evolution of magmatic hydrothermal deposits. Our data suggest that the ZYK has the highest potential for Mo-W mineralization. The ore-bearing plutons of ZYK and SBG were formed in a transitional tectonic setting from compression to extension, with the large-scale metallogeny triggered by slab melts at ca. 145 Ma. However, the ore-barren LJS batholith formed in an extension-related geodynamic setting at ∼115 Ma. Our study shows that different tectonic settings and consequent physico-chemical conditions dictated the ore potential of the intrusions in the Luanchuan ore district.

Possible lunar ores

NASA Technical Reports Server (NTRS)

Gillett, Stephen L.

1991-01-01

Despite the conventional wisdom that there are no lunar ores, geochemical considerations suggest that local concentrations of useful rare elements exist on the Moon in spite of its extreme dryness. The Moon underwent protracted igneous activity in its history, and certain magmatic processes can concentrate incompatible elements even if anhydrous. Such processes include: (1) separation of a magma into immiscible liquid phases (depending on composition, these could be silicate-silicate, silicate-oxide, silicate-sulfide, or silicate-salt); (2) cumulate deposits in layered igneous intrusions; and (3) concentrations of rare, refractory, lithophile elements (e.g., Be, Li, Zr) in highly differentiated, silica-rich magmas, as in the lunar granites. Terrestrial mining experience indicates that the single most important characteristic of a potential ore is its concentration of the desire element. The utility of a planet as a resource base is that the welter of interacting processes over geologic time can concentrate rare element automatically. This advantage is squandered if adequate exploration for ores is not first carried out.

The Balmat-Edwards zinc-lead deposits-synsedimentary ore from Mississippi valley-type fluids.

USGS Publications Warehouse

Whelan, J.F.; Rye, R.O.; Delorraine, W.

1984-01-01

The Balmat-Edwards Zn-Pb district in New York is in Mid-Proterozoic Grenville marbles. Tabular to podiform, generally conformable massive sphalerite-galena orebodies occur at various horizons in the approx 1 km-thick marbles. Metamorphism obscured or obliterated most primary characteristics, whose reconstruction is attempted through detailed S, C, and O isotope studies of the Fowler orebody, and trace element and S isotope studies of sphalerite concentrates and composite ore samples from 22 orebodies. Sulphur isotope data reflect equilibration at near peak metamorphism with some indication of re-equilibration during retrograde metamorphism. The carbon and oxygen isotope composition of gangue carbonates suggests derivation from the host marbles. The oxygen isotope composition of gangue quartz is compatible with a chert origin or metamorphism-equilibration with other minerals. Sulphur and lead isotopes and sulphide mineralogy suggests that the ore fluids were evolved basin brines, chemically like those responsible for Mississippi Valley-type deposits. The large stratigraphic span (> 600 m) of the Balmat orebodies may be due to basin dewatering of million-year intervals. Stratigraphically increasing 34S values of evaporite-anhydrite are postulated to record hydrothermal events and to imply bacterial sulphate reduction on an unusually large scale. Such a stratigraphic increase may be a general exploration guide where sediment-hosted exhalative deposits or Mississippi Valley-type deposits occur.-G.J.N.

Geological controls on refractory ore in an orogenic gold deposit, Macraes mine, New Zealand

NASA Astrophysics Data System (ADS)

Petrie, B. S.; Craw, D.; Ryan, C. G.

2005-07-01

The Macraes mine is hosted in an orogenic (mesothermal) gold deposit in metasedimentary rocks of the Otago Schist belt. Much gold occurs within altered schist with minimal silica-addition, and this study focuses on altered schist ore types. The unmineralized host schists are chemically and mineralogically uniform in composition, but include two end-member rock types: feldspathic schist and micaceous schist. Both rock types have undergone hydrothermal alteration along a shallow-dipping foliation-parallel shear zone, but their different rheological properties have affected the style of mineralisation. Micaceous schist has been extensively recrystallized and hydrothermally altered during ductile deformation, to form ores characterized by abundant, disseminated millimetre-scale pyrite cubes (typically 1 2 wt% S) and minor silicification. The earliest pyrite contained Ni and/or As in solid solution and no gold was imaged in these pyrites or later arsenopyrite grains. The ore type is refractory and gold recovery by cyanide leaching is less than 50%, with lowest recovery in rocks that have been less affected by later brittle deformation. In contrast, hydrothermally altered feldspathic schist is characterized by mineralised black microshears and veinlets formed during shear-zone related brittle deformation. Microsheared ore has relatively low sulphur content (<0.7 wt%) and muscovite has been illitised during hydrothermal alteration. Pyrite and arsenopyrite in microshears are fractured and deformed, and contain 1 10 μm blebs of gold. Later pyrite veinlets also contain micron- to submicron-scale inclusions of sphalerite, chalcopyrite, galena, and gold (≤10 microns). Gold in microsheared ore is more readily recoverable than in the refractory ore, although encapsulation of the fine gold grains inhibits cyanidation. Both microsheared ore and disseminated pyritic ore pass laterally into mineralised black shears, which contain hydrothermal graphite and late-stage cataclastic sulphides. This black, sheared ore releases gold readily, but the gold is then adsorbed on to gangue minerals (preg-robbed) and net cyanidation recovery can be less than 50%. Hence, low gold recovery during cyanidation results from (1) poor liberation of gold encapsulated in microcrystalline quartz and unfractured sulphide grains, and (2) preg-robbing of liberated gold during cyanidation. Introduction of pressure-oxidation of ore prior to cynidation has mitigated these issues.

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

DOE PAGES

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

2016-05-20

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

Mercury isotope fractionation during ore retorting in the Almadén mining district, Spain

USGS Publications Warehouse

Gray, John E.; Pribil, Michael J.; Higueras, Pablo L.

2013-01-01

Almadén, Spain, is the world's largest mercury (Hg) mining district, which has produced over 250,000 metric tons of Hg representing about 30% of the historical Hg produced worldwide. The objective of this study was to measure Hg isotopic compositions of cinnabar ore, mine waste calcine (retorted ore), elemental Hg (Hg0(L)), and elemental Hg gas (Hg0(g)), to evaluate potential Hg isotopic fractionation. Almadén cinnabar ore δ202Hg varied from − 0.92 to 0.15‰ (mean of − 0.56‰, σ = 0.35‰, n = 7), whereas calcine was isotopically heavier and δ202Hg ranged from − 0.03‰ to 1.01‰ (mean of 0.43‰, σ = 0.44‰, n = 8). The average δ202Hg enrichment of 0.99‰ between cinnabar ore and calcines generated during ore retorting indicated Hg isotopic mass dependent fractionation (MDF). Mass independent fractionation (MIF) was not observed in any of the samples in this study. Laboratory retorting experiments of cinnabar also were carried out to evaluate Hg isotopic fractionation of products generated during retorting such as calcine, Hg0(L), and Hg0(g). Calcine and Hg0(L) generated during these retorting experiments showed an enrichment in δ202Hg of as much as 1.90‰ and 0.67‰, respectively, compared to the original cinnabar ore. The δ202Hg for Hg0(g) generated during the retorting experiments was as much as 1.16‰ isotopically lighter compared to cinnabar, thus, when cinnabar ore was roasted, the resultant calcines formed were isotopically heavier, whereas the Hg0(g) generated was isotopically lighter in Hg isotopes.

The composition of fluid inclusions in ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type Zn-Pb deposits Poland: Genetic and environmental implications

USGS Publications Warehouse

Viets, J.G.; Hofstra, A.H.; Emsbo, P.; Kozlowski, A.

1996-01-01

The composition of fluids extracted from ore and gangue sulfide minerals that span most of the paragenesis of the Silesian-Cracow district was determined using a newly developed ion chromatographic (IC) technique. Ionic species determined were Na+, NH+4, Ca2+, Mg2+, K+, Rb+, Sr2+, Ba2+, Cl-, Br-, F-, I-, PO3-4, CO2-3, HS-, S2O2-3, SO2-4, NO-3, and acetate. Mineral samples included six from the Pomorzany mine and one from the Trzebionka mine which are hosted in the Triassic Muschelkalk Formation, and two samples of drill core from mineralized Upper Devonian strata. Nine paragenetically identifiable sulfide minerals occur throughout the Silesian-Cracow district. These include from earliest to latest: early iron sulfides, granular sphalerite, early galena, light-banded sphalerite, galena, dark-banded sphalerite, iron sulfides, late dark-banded sphalerite with late galena, and late iron sulfides. Seven of the minerals were sampled for fluid inclusion analysis in this study. Only the early iron sulfides and the last galena stage were not sampled. Although the number of analyses are limited to nine samples and two replicates and there is uncertainty about the characteristics of the fluid inclusions analyzed, the data show clear temporal trends in the composition of the fluids that deposited these minerals. Fluid inclusions in minerals deposited later in the paragenesis have significantly more K+, Br-, NH+4, and acetate but less Sr2+ than those deposited earlier in the paragenesis. The later minerals are also characterized by isotopically lighter sulfur and significantly more Tl and As in the solid minerals. The change in ore-fluid chemistry is interpreted to reflect a major change in the hydrologic regime of the district. Apparently, the migrational paths of ore fluids from the Upper Silesian basin changed during ore deposition and the fluids which deposited early minerals reacted with aquifers with very different geochemical characteristics than those that deposited late minerals. The early fluids may have reacted primarily with Devonian and Lower Carboniferous carbonate aquifers deeper in the basin, whereas the later fluids appear to have had extensive contact with organic-rich rocks, probably the shallower Middle and Upper Carboniferous flysch associated with coal measures. High concentrations of toxic Tl and As occur in the readily oxidized marcasite and pyrite minerals deposited by the later fluids. In general, the geochemistry of both the early and late fluids may be explained by an evaporite related origin or by water-rock modification of a saline basinal brine. When compared to the composition of fluid inclusions in Mississippi Valley-type (MVT) ore minerals from the Ozark region of the United States, fluid inclusions in minerals from Silesian-Cracow are fundamentally different, containing more Ca2+, Mg2+, NH+4, Br-, Sr2+ and acetate in all mineral stages with significantly more K+ in later stage minerals. The differences in ore fluid chemistry between the two regions are consistent with the lithologic differences of the respective basins thought to be the source of the mineralizing brines.

Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

NASA Astrophysics Data System (ADS)

Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

2015-04-01

India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled with kaolinite and gibbsite, which make it low grade. Massive iron ores are devoid of any lamination and usually associated with BHJ and lower shale. The thickness of the massive ore layer varies with the location. The massive iron ore grades in to well-developed bedded BHJ in depth. Blue dust occurs in association with BHJ as pockets and layers. Although blue dust and friable ore are both powdery ores, and subjected to variable degree of deformation, leading to the formation of folding, faulting and joints of complex nature produce favourable channels. Percolating water play an important role in the formation of blue dust and the subterranean solution offers the necessary acidic environment for leaching of quartz from the BHJ. The dissolution of silica and other alkalis are responsible for the formation of blue dust. The friable and powdery ore on the other hand are formed by soft laminated ore. As it is formed from the soft laminated ore, its alumina content remains high similar to soft laminated ore compaired to blue dust. Mineralogy study suggests that magnetite was the principal iron oxide mineral, now a relict phase whose depositional history is preserved in BHJ, where it remains in the form of martite. The platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Hard laminated ores, martite-goethite ore and soft laminated ore are resultant of desilicification process through the action of hydrothermal fluids. Geochemistry of banded iron-formations of the Noamundi-Koira iron ore deposits shows that they are detritus-free chemical precipitates. The mineralogical and geochemical data suggest that the hard laminated, massive, soft laminated ores and blue dust had a genetic lineage from BIF's aided with certain input from hydrothermal activity. The comparative study of major elemental composition of the basin samples and while plotting a binary diagram, it shows a relation between major oxides against iron oxides, in which iron oxides is taken as a reference oxide (Mirza, 2011). On the other hand, by plotting a binary diagram between chemical index of alteration (CIA) and other oxides while taking the samples of lower, middle and upper shales. It reflects an immobility and mobility of ions during partial and complete weathering processes (Mirza, 2011). Geochemical data indicate that BIF are in general detritus free chemical precipitates. Fe2O3 content of BHJ are varies in between 36.6% to 65.04%. In hard laminated ore, Fe2O3 content varies from 93.8% to 96.38%, Soft laminated ore varies from 83.64% to 89.5% and laterite ore varies from 53.5% to 79.11%. Fe2O3 content in Martite- Goethite ore varies from 86.38% to 89.42% and blue dust having 90.74% to 95.86% and all other oxides like SiO2, Al2O3, CaO, MgO, K2O, Na2O are decreases. Major part of the iron could have been added to the bottom sea water by hydrothermal solutions derived from hydrothermally active anoxic marine environments. The presence of intacalated tuffaceous shales pointing towards the genesis of iron, which could have leached from sea floor by volcanogenic process. Iron and silica of BIF were provided by the hydrothermal solutions emplaced at the vent sites situated at the Archean-Mid Oceanic Ridges. References: Mirza A (2011). Major element geochemistry of iron ore deposits in Noamundi-Koira basin of Singhbhum-Orissa craton (India). MSc thesis, Aligarh Muslim University, India. Saha AK (1994). Crustal evolution of Singhbhum, North Orissa, Eastern India; Geol. Soc. India Memoir 27 341. Sharma M, Basu AR and Ray SL (1994). Sm-Nd isotopic and geochemical study of the Archaean tonalite-amphibolite association from the eastern Indian craton. Contrib. Mineral Petrol. 117:45-55. Van Schalkwyk J and Beukes N J (1986). The Sishen iron ore deposit, Griqualand West; In: Mineral deposits of Southern Africa (eds) Annhaeusser C R and Maske S S, Geological Society of South Africa, Johannesburg, 931-956.

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

NASA Astrophysics Data System (ADS)

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

2014-04-01

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

The physical hydrogeology of ore deposits

USGS Publications Warehouse

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

2012-01-01

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

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

NASA Astrophysics Data System (ADS)

Wang, Ying; Xie, Yuling; Wu, Haoran

2018-02-01

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

Sediment-hosted Pb-Zn Deposits: a global perspective

USGS Publications Warehouse

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

2005-01-01

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

Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

PubMed Central

Watling, Helen R.; Shiers, Denis W.; Collinson, David M.

2015-01-01

In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II) and/or reduced inorganic sulphur compounds (RISC), such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As) to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity. PMID:27682094

Armor-Piercing Shot Processed from Molybdenum Bearing Tungsten Carbide

DTIC Science & Technology

1959-03-01

study were of the same contour aa WC cores employed in all previous scale model terminal ballistic studies of the effect of core composition on...Pennsylvania, by cold pressing and sintering techniques from their composition WS12. This composition is reduced from low grade western ores without the...removal of Mo and results in a product of the following composition after the tungsten is carburized and the binder is added: WC 87.4% Co. 12% Mo

The choice of iron-containing filling for composite radioprotective material

NASA Astrophysics Data System (ADS)

Matyukhin, P. V.

2018-03-01

The paper presents the data the composition of modern composite building materials including materials which in addition to high physical-mechanical have radio-protective properties. The article presents infrared researches and differential thermal data of fine-grained magnetite and hematite beneficiated iron-ore concentrates. The choice of the most suitable filling for new composite radio-protective building material engineering and development was made basing on the magnetite and hematite data presented in the paper.

Hercynian Pb-Zn mineralization types in the Alcudia Valley mining district (Spain) and their reflect in Pb isotopic signatures

NASA Astrophysics Data System (ADS)

García de Madinabeitia, S.; Santos Zalduegui, J. F.; Palero, F.; Gil Ibarguchi, J. I.; Carracedo, M.

2003-04-01

More than 450 ore deposits indexed within the Alcudia Valley of the Central-Iberian Zone (Spain) may be grouped by their tectonic and lithologic characteristics (1,2) as follows: type A of rare stratabound mineralizations, and types B, C, D and E represented by abundant Hercynian veins (post-Namurian). 86 new Pb isotope analyses of galenas from the four vein types reveal that types B and C have similar isotopic ratios with values of μ_2 = 10.07, ω_2 = 40.6 and a mean model age of 564 Ma. Types D and E have μ_2 and ω_2 values of 9.79 and 38.5, respectively, but differ each other with respect to their model ages, 600 Ma (type D) and 335 Ma (type E). The observed variations appear to be related to the geochemical features of the metasedimentary host-rocks of the mineralizations where two distinct types of Pb isotopic ratios have been reported (3): one with μ_2 and ω_2 comparable to those of the D and E types and another with a more radiogenic composition, close to those of the B and C types of galenas. Nägler et al. have suggested partial rehomogeneization of Pb isotopic composition within the metasediments at ca. 330 Ma, that is, prior to the mineralization events, but the extent of this process and its effects on the ore bodies isotopic features is not evident. The origin of the more abundant E type ore bodies has been related to the Hercynian granitic rocks in the area (2, and references therein). Other plutons within this sector of the Central Iberian Zone (e.g., Linares, etc.; cf. accompanying Abstract) associate ore bodies whose Pb isotopic composition is very similar to that of the E type galenas from the Alcudia Valley. The isotopic data obtained thus point to a related or common source material for the various types of granites within the area studied. Yet, the Pb isotopic composition of other mineralizations (B, C, D), likewise located in Hercynian veins, allow to consider different types of Pb-Zn ore bodies and point therefore to different sources of Pb at a regional scale. (1) Palero, F.J. Ph. D., University of Salamanca, Spain (1991). (2) Palero, F.; Both, R.A.; Arribas, A.; Boyce, A.J.; Mangas, J. &Martín-Izard, A. Economic Geology (in press). (3) Nägler, T. Ph. D., Diss ETH, Zurich N^o 9245 (1990).

Magmatic controls on the genesis of porphyry Cu-Mo-Au deposits: The Bingham Canyon example

NASA Astrophysics Data System (ADS)

Grondahl, Carter; Zajacz, Zoltán

2017-12-01

Bingham Canyon is one of the world's largest porphyry Cu-Mo-Au deposits and was previously used as an example to emphasize the role of magma mixing and magmatic sulphide saturation in the enhancement of ore fertility of magmatic systems. We analyzed whole rocks, minerals, and silicate melt inclusions (SMI) from the co-genetic, ore-contemporaneous volcanic package (∼38 Ma). As opposed to previous propositions, whole-rock trace element signatures preclude shoshonite-latite genesis via mixing of melanephelinite and trachyte or rhyolite, whereas core to rim compositional profiles of large clinopyroxene phenocrysts suggests the amalgamation of the ore-related magma reservoir by episodic recharge of shoshonitic to latitic magmas with various degrees of differentiation. Major and trace element and Sr and Nd isotopic signatures indicate that the ore-related shoshonite-latite series were generated by low-degree partial melting of an ancient metasomatized mantle source yielding volatile and ore metal rich magmas. Latite and SMI compositions can be reproduced by MELTS modeling assuming 2-step lower and upper crustal fractionation of a primary shoshonite with minimal country rock assimilation. High oxygen fugacities (≈ NNO + 1) are prevalent as evidenced by olivine-spinel oxybarometry, high SO3 in apatite, and anhydrite saturation. The magma could therefore carry significantly more S than would have been possible at more reducing conditions, and the extent of ore metal sequestration by magmatic sulphide saturation was minimal. The SMI data show that the latites were Cu rich, with Cu concentrations in the silicate melt reaching up to 300-400 ppm at about 60 wt% SiO2. The Au and Ag concentrations are also high (1.5-4 and 50-200 ppb, respectively), but show less variation with SiO2. A sudden drop in Cu and S concentrations in the silicate melt at around 65 wt% SiO2 in the presence of high Cl, Mo, Ag, and Au shows that the onset of effective metal extraction by fluid exsolution occurred at a relatively late stage of magma evolution. Overall, our results show that fluid exsolution during simple magmatic differentiation of oxidized alkaline magmas is capable of producing giant porphyry Cu deposits.

Analysis of Greek small coinage from the classic period

NASA Astrophysics Data System (ADS)

Šmit, Ž.; Šemrov, A.

2018-02-01

A series of 25 Greek coins from the 6th to 4th centuries BC was studied by PIXE for their trace element composition, with an aim to discover the origin of their silver ore. The procedure revealed a counterfeited coin, and then concentrated on distinguishing the coins minted from the ore of Laurion on the Attica peninsula and the coins minted from other sources. Linear discriminant analysis based on the impurities and alloying elements of copper, gold, lead and bismuth revealed that discrimination is indeed possible according to a single canonical variable.

Rock-magnetism and ore microscopy of the magnetite-apatite ore deposit from Cerro de Mercado, Mexico

NASA Astrophysics Data System (ADS)

Alva-Valdivia, L. M.; Goguitchaichvili, A.; Urrutia-Fucugauchi, J.; Caballero-Miranda, C.; Vivallo, W.

2001-03-01

Rock-magnetic and microscopic studies of the iron ores and associated igneous rocks in the Cerro de Mercado, Mexico, were carried out to determine the magnetic mineralogy and origin of natural remanent magnetization (NRM), related to the thermo-chemical processes due to hydrothermalism. Chemical remanent magnetization (CRM) seems to be present in most of investigated ore and wall rock samples, replacing completely or partially an original thermoremanent magnetization (TRM). Magnetite (or Ti-poor titanomagnetite) and hematite are commonly found in the ores. Although hematite may carry a stable CRM, no secondary components are detected above 580°, which probably attests that oxidation occurred soon enough after the extrusion and cooling of the ore-bearing magma. NRM polarities for most of the studied units are reverse. There is some scatter in the cleaned remanence directions of the ores, which may result from physical movement of the ores during faulting or mining, or from perturbation of the ambient field during remanence acquisition by inhomogeneous internal fields within these strongly magnetic ore deposits. The microscopy study under reflected light shows that the magnetic carriers are mainly titanomagnetite, with significant amounts of ilmenite-hematite minerals, and goethite-limonite resulting from alteration processes. Magmatic titanomagnetites, which are found in igneous rocks, show trellis, sandwich, and composite textures, which are compatible with high temperature (deuteric) oxy-exsolution processes. Hydrothermal alteration in ore deposits is mainly indicated by martitization in oxide minerals. Grain sizes range from a few microns to >100 mm, and possible magnetic state from single to multidomain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and IRM (isothermal remanent magnetization) acquisition suggest a predominance of spinels as magnetic carriers, most probably titanomagnetites with low-Ti content. For quantitative modeling of the aeromagnetic anomalies, we used data on bulk susceptibility and natural remanent intensity for quantifying the relative contributions of induced and remanent magnetization components and allow a better control of the geometry of source bodies. The position and geometry of this magnetic source are shown as an ENE-striking tabular body, steeply inclined (75°) to the south.

Some limitations on the possible composition of the ore-forming fluid

USGS Publications Warehouse

Barton, Paul B.

1956-01-01

The activity rations of various important anions (S, CO3, SO4, OH, F, and Cl) in hydrothermal solutions at the time of deposition are evaluated using a simple thermodynamic technique. The rations are interpreted in the light of the mineralogy of ore deposits and limites are placed on the variability of each ratio in hydrothermal solutions. All of the calculations are made for 25°C and cautious extrapolation to higher temperatures seems justified; however, additional data for elevated temperatures and pressures are needed before more than approximate values may be assigned to these ratios in the ore-forming fluid. The calculated partial pressure of CO2 in the ore fluid is generally less than one atmosphere, which suggests that a dense CO2 phase cannot be considered an importatn ore fluid for most deposits. The partial pressure of H2S is usually less than 10-4 atmospheres which makes it extremely difficult to defend the heory that metals (other than the easily complexible mercury, arsenic, antimony, and perhaps fols and silver) are transported in quantity as complex sulfide and hydrosulfides. The sulfate to sulfide ration is such that the oxidation potential at the time of deposition is defined by the following equation: Eh (in volts) = 0.22 ± 0.04 - 0.059 pH.

Tectono-Magmatic Cycles and Geodynamic Settings of Ore-Bearing System Formation in the Southern Cis-Argun Region

NASA Astrophysics Data System (ADS)

Petrov, V. A.; Andreeva, O. V.; Poluektov, V. V.; Kovalenko, D. V.

2017-11-01

The ore-bearing geological structural units of the southern Cis-Argun region are considered in the context of varying geodynamic regimes related to the Proterozoic, Caledonian, and Hercynian tectono-magmatic cycles, as well as during the Late Mesozoic within-plate tectono-magmatic activity, which give rise to the formation of subalkaline igneous rocks of the Shakhtama Complex with Au, Cu-Mo, Pb-Zn-Ag metallogenic specialization; volcano-plutonic complexes of calderas with Mo-U, Pb-Zn, and fluorite ores; and rare-metal granite of the Kukulbei Complex with a Sn-W-Li-Ta spectrum of mineralization. The comparative geochemical characteristics inherent to Mesozoic ore-bearing felsic igneous rocks are considered, as well as geodynamic settings of ore-bearing fluido-magmatic systems, taking into consideration new data on geochemistry of bimodal trachybasalt-trachydacite series and rhyolite of the Turga Series, which fill the Strel'tsovka Caldera, whose trend of evolution is defined as a reference for geological history of the studied territory. The geodynamic conditions, phase composition, and geochemistry of rocks along with metallogenic specialization of Mesozoic volcano-plutonic complexes of southern Cis-Argun region are close to those of the Great Khingan Belt in northeastern China and eastern Mongolia.

Seaching for a Silver Lining: Using Pb Isotopes to Constrain the Source of Argentiferous Galena at La Isabela

NASA Astrophysics Data System (ADS)

Thibodeau, A. M.; Killick, D. J.; Ruiz, J.; Chesley, J. T.; Baker, M.

2005-12-01

This study investigates the smelting and refining of argentiferous galena at La Isabela, Dominican Republic (1493-1498), the town founded by Columbus on his second voyage to the Americas. Archaeologists recovered approximately 100 kilograms of galena and 200 kilograms of metallurgical slag near the remains of a crude furnace unearthed at the site (Deagan and Cruxent 2002). The purpose of this study was to determine if these remains are evidence that members of Columbus's fleet prospected for silver during his second expedition. Samples of ore and slag were examined as metallographic polished sections, and petrographic thin sections by optical and scanning electron microscopes. The composition of the ore and slag allows us to infer these ores were processed in a two-stage procedure to produce silver metal and a lead silicate slag. Electron microprobe analysis of galena indicates highly variable but low Ag content (50 ppm), which may account for the fact some of the ore was left unprocessed. Lead isotope analysis by multi-collector ICP-MS indicates that the galena likely came from a single source and was not mined within the Caribbean. Instead, the isotopic signature of these ores is consistent with an Old World source, possibly in the Linares-La Carolina Pb-Zn vein field of southwestern Spain.

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.

Analytical fingerprint for tantalum ores from African deposits

NASA Astrophysics Data System (ADS)

Melcher, F.; Graupner, T.; Sitnikova, M.; Oberthür, T.; Henjes-Kunst, F.; Gäbler, E.; Rantitsch, G.

2009-04-01

Illegal mining of gold, diamonds, copper, cobalt and, in the last decade, "coltan" has fuelled ongoing armed conflicts and civil war in a number of African countries. Following the United Nations initiative to fingerprint the origin of conflict materials and to develop a traceability system, our working group is investigating "coltan" (i.e. columbite-tantalite) mineralization especially in Africa, also within the wider framework of establishing certified trading chains (CTC). Special attention is directed towards samples from the main Ta-Nb-Sn provinces in Africa: DR Congo, Rwanda, Mozambique, Ethiopia, Egypt and Namibia. The following factors are taken into consideration in a methodological approach capable of distinguishing the origin of tantalum ores and concentrates with the utmost probability: (1) Quality and composition of coltan concentrates vary considerably. (2) Mineralogical and chemical compositions of Ta-Nb ores are extremely complex due to the wide range of the columbite-tantalite solid solution series and its ability to incorporate many additional elements. (3) Coltan concentrates may contain a number of other tantalum-bearing minerals besides columbite-tantalite. In our approach, coltan concentrates are analyzed in a step-by-step mode. State-of-the-art analytical tools employed are automated scanning electron microscopy (Mineral Liberation Analysis; MLA), electron microprobe analysis (major and trace elements), laser ablation-ICP-MS (trace elements, isotopes), and TIMS (U-Pb dating). Mineral assemblages in the ore concentrates, major and trace element concentration patterns, and zoning characteristics in the different pegmatites from Africa distinctly differ from each other. Chondrite-normalized REE distribution patterns vary significantly between columbite, tantalite, and microlite, and also relative to major element compositions of columbites. Some locations are characterized by low REE concentrations, others are highly enriched. Samples with Kibaran age either show flat patterns for most tantalites, rising values from the LREE to the HREE, or trough-like patterns. Eu anomalies are strongly negative in columbite-tantalite from the Alto Ligonha Province in Mozambique, from the Namaqualand Province (Namibia, South Africa), and from Zimbabwe. Four main age populations of coltan deposits in Africa were revealed: (1) Archean (>2.5 Ga), (2) Paleoproterozoic (2.1-1.9 Ga), (3) early Neoproterozoic ("Kibaran", 1.0-0.9 Ga), and (4) late Neoproterozoic to early Paleozoic (Pan-African; ca. 0.6-0.4 Ga). Currently, we focus on the resolution of the fingerprinting system from region via ore province down to deposit scale, establishing a large and high-quality analytical data base, and developing fast-screening and low-cost methods. Analytical flow-charts and identification schemes for coltan ores will be presented at the Conference. The analytical results obtained so far indicate that a certification scheme including fingerprinting of sources of coltan ores is feasible. The methodology developed is capable to assist in the establishment of a control instrument in an envisaged certification of the production and trade chain of coltan.

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

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

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

1953-12-22

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

Textures and trace element composition of pyrite from the Bukit Botol volcanic-hosted massive sulphide deposit, Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Basori, Mohd Basril Iswadi; Gilbert, Sarah; Large, Ross Raymond; Zaw, Khin

2018-06-01

The Bukit Botol volcanic-hosted massive sulphide (VHMS) deposit is located in the Central Belt of Peninsular Malaysia. The deposit occurs in a package of Permian-aged coherent felsic volcanic and volcaniclastic rocks which have a geochemical signature indicative of a volcanic arc tectonic setting. Mineralisation shows distinct ore zonation, forming a stringer to massive sulphide zone at the footwall followed by barite lenses and exhalite layers (Fe-Mn ore) at the top. Mineralogy is characterised by pyrite as the major sulphide mineral, with minor chalcopyrite, sphalerite, and rare galena; traces of gold, silver- and tin-bearing minerals also occur in the massive sulphide and barite ores. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis combined with the textural characteristics of pyrite provides evidence for significant variations of trace elements in different pyrite types at Bukit Botol, having three types of pyrite in the paragenetic sequence. The concentrations of As, Se, Te, Cu, Zn and Pb decrease from the early pyrite 1 to the late stage pyrite 3, and the Co/Ni ratios vary for the three pyrite types. The combined textural and compositional data of pyrite suggest that the hydrothermal fluid responsible for mineralisation evolved from an early, high temperature, reduced, low pH and desulphurized fluid to more S-rich, oxidized, high pH and cooler fluid. Available sulphur isotope data from the Bukit Botol deposit point to reduced seawater, along with a possible magmatic contribution, as the most probable sources for the ore-forming fluids.

Contrasting hydrological processes of meteoric water incursion during magmatic-hydrothermal ore deposition: An oxygen isotope study by ion microprobe

NASA Astrophysics Data System (ADS)

Fekete, Szandra; Weis, Philipp; Driesner, Thomas; Bouvier, Anne-Sophie; Baumgartner, Lukas; Heinrich, Christoph A.

2016-10-01

Meteoric water convection has long been recognized as an efficient means to cool magmatic intrusions in the Earth's upper crust. This interplay between magmatic and hydrothermal activity thus exerts a primary control on the structure and evolution of volcanic, geothermal and ore-forming systems. Incursion of meteoric water into magmatic-hydrothermal systems has been linked to tin ore deposition in granitic plutons. In contrast, evidence from porphyry copper ore deposits suggests that crystallizing subvolcanic magma bodies are only affected by meteoric water incursion in peripheral zones and during late post-ore stages. We apply high-resolution secondary ion mass spectrometry (SIMS) to analyze oxygen isotope ratios of individual growth zones in vein quartz crystals, imaged by cathodo-luminescence microscopy (SEM-CL). Existing microthermometric information from fluid inclusions enables calculation of the oxygen isotope composition of the fluid from which the quartz precipitated, constraining the relative timing of meteoric water input into these two different settings. Our results confirm that incursion of meteoric water directly contributes to cooling of shallow granitic plutons and plays a key role in concurrent tin mineralization. By contrast, data from two porphyry copper deposits suggest that downward circulating meteoric water is counteracted by up-flowing hot magmatic fluids. Our data show that porphyry copper ore deposition occurs close to a magmatic-meteoric water interface, rather than in a purely magmatic fluid plume, confirming recent hydrological modeling. On a larger scale, the expulsion of magmatic fluids against the meteoric water interface can shield plutons from rapid convective cooling, which may aid the build-up of large magma chambers required for porphyry copper ore formation.

Fluid evolution and ore genesis of the Dalingshang deposit, Dahutang W-Cu ore field, northern Jiangxi Province, South China

NASA Astrophysics Data System (ADS)

Peng, Ning-Jun; Jiang, Shao-Yong; Xiong, Suo-Fei; Pi, Dao-Hui

2018-02-01

The Dalingshang W-Cu deposit is located in the North section of the Dahutang ore field, northern Jiangxi Province, South China. Vein- and breccia-style tungsten-copper mineralization is genetically associated with Mesozoic S-type granitic rocks. Infrared and conventional microthermometric studies of both gangue and ore minerals show that the homogenization temperatures for primary fluid inclusions in wolframite ( 340 °C) are similar to those in scheelite ( 330 °C), but about 40 °C higher than those of apatite ( 300 °C) and generally 70 °C higher than those in coexisting quartz ( 270 °C). Laser Raman analysis identifies CH4 and N2 without CO2 in fluid inclusions in scheelite and coexisting quartz, while fluid inclusions in quartz of the sulfide stage have variable CO2 content. The ore-forming fluids overall are characterized by high- to medium-temperature, low-salinity, CH4, N2, and/or CO2-bearing aqueous fluids. Chalcopyrite, muscovite, and sphalerite are the most abundant solids recognized in fluid inclusions from different ores. The H-O-S-Pb isotope compositions favor a dominantly magmatic origin for ores and fluids, while some depleted δ34S values (- 14.4 to - 0.9‰) of sulfides from the sulfide stage are most likely produced by an increase of oxygen fugacity, possibly caused by inflow of oxidized meteoric waters. The microthermometric data also indicate that a simple cooling process formed early scheelite and wolframite. However, increasing involvement of meteoric waters and fluid mixing may trigger a successive deposition of base metal sulfides. Fluid-rock interaction was critical for scheelite mineralization as indicated by in-situ LA-ICP-MS analysis of trace elements in scheelite.

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

USGS Publications Warehouse

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

1994-01-01

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

The Stability of Rankings Derived from Composite Indicators: Analysis of the "IL Sole 24 Ore" Quality of Life Report

ERIC Educational Resources Information Center

Lun, G.; Holzer, D.; Tappeiner, G.; Tappeiner, U.

2006-01-01

The calculation of composite indicators and the derivation of respective rankings is a common method used to benchmark countries or regions. However, although the statistical robustness of these rankings is often criticised, they often still spark off heated political debate. Here, we assess the sensitivity of the province ranking published by the…

Osmium isotope constraints on ore metal recycling in subduction zones

PubMed

McInnes; McBride; Evans; Lambert; Andrew

1999-10-15

Veined peridotite xenoliths from the mantle beneath the giant Ladolam gold deposit on Lihir Island, Papua New Guinea, are 2 to 800 times more enriched in copper, gold, platinum, and palladium than surrounding depleted arc mantle. Gold ores have osmium isotope compositions similar to those of the underlying subduction-modified mantle peridotite source region, indicating that the primary origin of the metals was the mantle. Because the mantle is relatively depleted in gold, copper, and palladium, tectonic processes that enhance the advective transport and concentration of these fluid soluble metals may be a prerequisite for generating porphyry-epithermal copper-gold deposits.

Extreme variation of sulfur isotopic compositions in pyrite from the Qiuling sediment-hosted gold deposit, West Qinling orogen, central China: An in situ SIMS study with implications for the source of sulfur

USGS Publications Warehouse

Chen, Lei; Li, Xian-hua; Li, Jian-wei; Hofstra, Albert H.; Liu, Yu; Koenig, Alan E.

2015-01-01

High spatial resolution textural (scanning electron microscope (SEM)), chemical (electron microprobe (EMP)) and laser ablation-inductively coupled plasma-mass spec- trometry (LA-ICP-MS)), and sulfur isotopic (secondary ion mass spectrometry (SIMS)) analyses of pyrite from the Qiuling sediment-hosted gold deposit (232±4 Ma) in the West Qinling orogen, central China were conducted to distinguish pyrite types and gain insights into the source and evolution of sulfur in hydrothermal fluids. The results reveal an enormous variation (−27.1 to +69.6‰) in sulfur isotopic composition of pyrite deposited during three paragenetic stages. Pre-ore framboidal pyrite, which is characterized by low concentra- tions of As, Au, Cu, Co, and Ni, has negative δ34S values of −27.1 to −7.6‰ that are interpreted in terms of bacterial re- duction of marine sulfate during sedimentation and diagenesis of the Paleozoic carbonate and clastic sequences, the predom- inant lithologies in the deposit area, and the most important hosts of many sediment-hosted gold deposits throughout the West Qinling orogen. The ore-stage hydrothermal pyrite con- tains high concentrations of Au, As, Cu, Sb, Tl, and Bi and hasa relatively narrow range of positive δ34S values ranging from +8.1 to +15.2‰. The sulfur isotope data are comparable to those of ore pyrite from many Triassic orogenic gold deposits and Paleozoic sedimentary exhalative (SEDEX) Pb-Zn de- posits in the West Qinling orogen, both being hosted mainly in the Devonian sequence. This similarity indicates that sulfur, responsible for the auriferous pyrite at Qiuling, was largely derived from the metamorphic devolatization of Paleozoic marine sedimentary rocks. Post-ore-stage pyrite, which is sig- nificantly enriched in Co and Ni but depleted in Au and As, has unusually high δ34S values ranging from +37.4 to +69.6 ‰, that are interpreted to result from thermochemical reduc- tion of evaporite sulfates in underlying Cambrian sedimentary rocks with very high δ34S values. The variations in Au content and sulfur isotopic compositions across a single ore-stage py- rite grain may reflect displacement of indigenous groundwater with low δ34S values by auriferous metamorphic fluids with high δ34S values. The very low-grade metamorphism of the host rocks and the metamorphic derivation of sulfur for the ore pyrite indicate that the Qiuling sediment-hosted gold deposit is an epizonal manifestation of an orogenic gold system in the West Qinling orogen.

Tourmaline in Appalachian - Caledonian massive sulphide deposits and its exploration significance.

USGS Publications Warehouse

Slack, J.F.

1982-01-01

Tourmaline is a common gangue mineral in several types of stratabound mineral deposits, including some massive base-metal sulphide ores of the Appalachian - Caledonian orogen. It is most abundant (sometimes forming massive foliated tourmalinite) in sediment-hosted deposits, such as those at the Elizabeth Cu mine and the Ore Knob Cu mine (North Carolina, USA). Trace amounts of tourmaline occur associated with volcanic-hosted deposits in the Piedmont and New England and also in the Trondheim district. Tourmaline associated with the massive sulphide deposits are Mg- rich dravites with major- and trace-element compositions significantly different from schorl. It is suggested that the necessary B was produced by submarine exhalative processes as a part of the same hydrothermal system that deposited the ores. An abundance of dravite in non-evaporitic terrains is believed to indicate proximity to former subaqueous fumarolic centres.-R.A.H.

Plaster-based magnetite composite materials in construction

NASA Astrophysics Data System (ADS)

Klimenko, V. G.; Kashin, G. A.; Prikaznova, T. A.

2018-03-01

Calculation and experimental data demonstrate the possibility of using iron-ore concentrate of Lebedinsky Mining and Processing Plant (Lebedinsky GOK) in the production of plaster concrete. Their physical-mechanical, thermal and radiation protective properties were studied. Structurization mechanisms in plaster magnetite systems depending on the type of plaster binder, textures and the structure of plaster crystals providing for the design of composite materials with predetermined properties are suggested. Composite materials to ensure protection against X-ray radiation are obtained.

Resource availability at Taurus-Littrow

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Colson, R. O.

1992-01-01

Early lunar technologies will probably use a common lunar material as ore. They will be robust to minor fluctuations in feedstock composition and will not require appreciable feedstock beneficiation such as rock grinding or mineral concentration. Technologies using unprocessed soil and indifferent to its composition will have the advantage. Nevertheless, the size and grade of the ore body must be confirmed for even the most indiscriminate process. Simple uses such as heaping unprocessed lunar soil for thermal insulation or radiation shielding onto a habitat require that we know the depth of the regolith, the size distributions of its soils, the locations of large boulders, and the ease of excavation. Costs of detailed site surveys trade against restrictions on site selection and conservative engineering design to accommodate unknown conditions of a poorly explored site. Given the above considerations, we consider briefly some abundant lunar materials, their proposed uses, and technologies for their preparation, with particular attention to the Taurus-Littrow site.

Remote quantitative analysis of minerals based on multispectral line-calibrated laser-induced breakdown spectroscopy (LIBS).

PubMed

Wan, Xiong; Wang, Peng

2014-01-01

Laser-induced breakdown spectroscopy (LIBS) is a feasible remote sensing technique used for mineral analysis in some unapproachable places where in situ probing is needed, such as analysis of radioactive elements in a nuclear leak or the detection of elemental compositions and contents of minerals on planetary and lunar surfaces. Here a compact custom 15 m focus optical component, combining a six times beam expander with a telescope, has been built, with which the laser beam of a 1064 nm Nd ; YAG laser is focused on remote minerals. The excited LIBS signals that reveal the elemental compositions of minerals are collected by another compact single lens-based signal acquisition system. In our remote LIBS investigations, the LIBS spectra of an unknown ore have been detected, from which the metal compositions are obtained. In addition, a multi-spectral line calibration (MSLC) method is proposed for the quantitative analysis of elements. The feasibility of the MSLC and its superiority over a single-wavelength determination have been confirmed by comparison with traditional chemical analysis of the copper content in the ore.

Application of gold compositional analyses to mineral exploration in the United States

USGS Publications Warehouse

Antweiler, J.C.; Campbell, W.L.

1977-01-01

Native gold is a mineral composed of Au, Ag and Cu in solid solution and it usually contains one or more trace metals as lattice impurities, as mineral inclusions, in grain boundaries or in surface coatings. Alloy proportions of Au, Ag and Cu, together with certain other elements, can be thought of as constituting a gold "signature". Gold is associated with a great variety of ore deposits and has characteristic signatures for each of several types of ore deposits. Signatures for gold derived from igneous-metamorphic, hypothermal, mesothermal and epithermal deposits reflect conditions of ore formation by their content of Ag, Cu and characteristic associated elements. At higher temperatures of ore formation, gold has low Ag and high Cu content, and Bi and Pb are the most abundant trace elements. But at lower temperatures of ore formation, Ag is high, Cu is low, and Pb is the most abundant trace element. The same trend in gold signatures is observable in gold mining districts, such as Central City, Colorado, where zoning as shown by mineral assemblages indicates ore deposition at progressively lower temperatures as the distance from a central high-temperature zone increases. The signatures of gold may be useful in searching for porphyry Cu deposits. Signatures from Butte (Montana), Mineral Park (Arizona) and Cala Abajo (Puerto Rico), on the basis of limited sampling, are similar and distinctive. They are characterized by a similar assemblage of trace elements and are relatively high in both Ag and Cu. Another application of gold compositional data is in tracing placer gold to its bedrock source. For example, the Ag content of placer gold in the Tarryall district of Colorado differed from that of nearly all of the bedrock sources of gold found by early prospectors. However, one lightly prospected area peripheral to the Tertiary quartz monzonite stock at Montgomery Gulch contains gold with a Ag content similar to that of the placer gold. This area is the most likely source of the gold in the productive placers and may be a potential exploration target. Gold signatures may be useful in prospecting for metals other than gold. Several metals of low crustal abundance - notably Sn, W, Mo and the Pt group metals - are detected in analyses of some gold samples and may indicate economic deposits of these metals. ?? 1977.

Mineral chemistry of magnetite from magnetite-apatite mineralization and their host rocks: examples from Kiruna, Sweden, and El Laco, Chile

NASA Astrophysics Data System (ADS)

Broughm, Shannon G.; Hanchar, John M.; Tornos, Fernando; Westhues, Anne; Attersley, Samuel

2017-12-01

Interpretation of the mineralizing environment of magnetite-apatite deposits remains controversial with theories that include a hydrothermal or magmatic origin or a combination of those two processes. To address this controversy, we have analyzed the trace element content of magnetite from precisely known geographic locations and geologic environments from the Precambrian magnetite-apatite ore and host rocks in Kiruna, Sweden, and the Pliocene-Holocene El Laco volcano in the Atacama desert of Chile. Magnetite samples from Kiruna have low trace element concentrations with little chemical variation between the ore, host, and related intrusive rocks. Magnetite from andesite at El Laco, and dacite from the nearby Láscar volcano, has high trace element concentrations typical of magmatic magnetite. El Laco ore magnetite have low trace element concentrations and displays growth zoning in incompatible elements (Si, Ca, and Ce), compatible elements (Mg, Al, and Mn), large-ion lithophile element (Sr), and high field strength element (Y, Nb, and Th). The El Laco ore magnetite are similar in composition to magnetite that has been previously interpreted to have crystallized from hydrothermal fluids; however, there is a significant difference in the internal zoning patterns. At El Laco, each zoned element is either enriched or depleted in the same layers, suggesting the magnetite crystallized from a volatile-rich, iron-oxide melt. In general, the compositions of magnetite from these two deposits plot in very wide fields that are not restricted to the proposed fields in published discriminant diagrams. This suggests that the use of these diagrams and genetic models based on them should be used with caution.

Mineralogy, alteration patterns, geochemistry, and fluid properties of the Ag-Au epithermal deposit Nová Baňa, Slovakia

NASA Astrophysics Data System (ADS)

Majzlan, Juraj; Berkh, Khulan; Kiefer, Stefan; Koděra, Peter; Fallick, Anthony E.; Chovan, Martin; Bakos, František; Biroň, Adrián; Ferenc, Štefan; Lexa, Jaroslav

2018-02-01

In this contribution, we report new data on mineralogy, alteration patterns, geochemistry, fluid properties and source of fluids for the deposit Nová Baňa, one of the smaller epithermal deposits in the Middle Miocene Štiavnica andesite stratovolcano (Western Carpathians, Slovakia). Ore veins and the associated rocks were studied in samples from outcrops and old mines, grab samples, and bore holes from the central part of the deposit (ore structures Althandel, Jozef, Jakub, Vavrinec), northern part (Freischurf), SE part (Gupňa) and SW part (Šibeničný vrch). Pervasive hydrothermal alteration transformed the rock-forming minerals into a mixture of adularia and fine-grained quartz, with lesser amount of pyrite, Ti oxides and Fe oxides. This assemblage was further altered to omnipresent interstratified illite/smectite that was used in this study as a geothermometer, corroborating the results from the fluid inclusion work. Ore minerals comprise predominantly pyrite, sphalerite, galena but all sulfides are relatively sparse in the samples studied. Minerals of precious metals are electrum, Ag-tetrahedrite, acanthite, members of the polybasite-pearceite and pyrargyrite-proustite solid solution, and rare miargyrite, Hg-Ag tetrahedrite, and diaphorite. In the central part, we have found also some stibnite. In the SE part of the deposit, acanthite, uytenbogaardtite, and petrovskaite occur and seem to be related to supergene enrichment of the ores. In bulk ore samples, Zn usually dominates over Pb and Cu. The average Ag:Au ratio for the entire deposit is 64:1. The concentrations of precious metals in the grab samples reach maxima of 50 ppm Au and 570 ppm Ag in the SE part and 116 ppm Au and 1110 ppm Ag in the central part of the deposit. Fluid inclusions show signs of trapping of a heterogeneous fluid. In the central, northern and SE parts of the deposit, homogenization temperatures of 190-260 °C and consistently low salinities of <5 wt% NaCl eq were recorded. In the SW part, primary fluid inclusions gave homogenization temperatures of 160-180 °C and similar low salinities. The secondary inclusions, however, show salinities up to 24 wt% NaCl eq., interpreted as fluid boiling almost to dryness. Isotopic composition of quartz and clay minerals is recalculated to fluid composition of -5.6 to -0.6 ‰ δ18Ofluid and -80 to -36 ‰ δDfluid, indicating mixed character of hydrothermal fluids falling between the compositions of magmatic and meteoric waters, with predominance of meteoric waters. Assuming hydrostatic pressure in the fluids, the measured data suggest paleodepths of ore formation of 50-170 m in the SW part of the ore deposit, 130-420 m in the SE and N parts, and a range of 120-470 m for the central part. These observations, comparison with other epithermal deposits in the Central Slovak volcanic field, and additional data from published literature show that Nová Baňa is a low- to intermediate sulfidation epithermal deposit, genetically associated to late rhyolitic volcanic activity in this area.

The application of microwave digestion in decomposing some refractory ore samples with solid fusion agent.

PubMed

Lu, Yan; Li, Gang; Liu, Wei; Yuan, Hongyan; Xiao, Dan

2018-08-15

It is known that most of the refractory ore are the basis of national economy and widely applied in various fields, however, the complexity of the chemical composition and the diversity of the crystallinity in the mineral phases make the sample pre-treatment of refractory ore still remains a challenge. In this work, the complete decomposition of the refractory ore sample can be achieved just by exposing the solid fusion agent and the refractory ore sample in the microwave irradiation environment for a few minutes, and induced by a drop of water. A digestion time of 15 min for 3.0 g solid fusion agent mixture of sodium peroxide/sodium carbonate (Na 2 O 2 /Na 2 CO 3 ) in a corundum crucible via microwave heating is sufficient to decompose 0.1 g refractory ore sample. An excellent microwave digestion solid agent should meet the following conditions, a good decomposition ability, an outstanding ability of absorbing microwave energy and converting it into heat quickly, a higher melting point than the decomposing temperature of the ore sample. In the research, the induction effect of water plays an important role for the microwave digestion. The energy which is released by the reaction of water and the solid fusion agent (Na 2 O 2 ) is the key to decompose refractory ore samples with solid fusion agent, which replenished the total energy required for the microwave digestion and made the microwave digestion completed successfully. This microwave digestion technique has good reproducibility and precision, RSD % for Mo, Fe, Ti, Cr and W in the refractory ore samples were all better than 6, except RSD % for Be of about 8 because of the influence of matrix-effect. Meanwhile, the analysis results of the elements in the refractory ore samples provided by the microwave digestion technique were all in good agreement with the analysis results provided by the traditional fusion method except for Cr in the mixture ore samples. In the study, the non-linear dependence of the electromagnetic and thermal properties of the solid fusion agent on temperature under microwave irradiation and the selective heating of microwave are fully applied in this simple microwave technique. Comparing to the traditional fusion decomposition method, this microwave digestion technique is a simple, economical, fast and energy-saving sample pre-treatment technique. Copyright © 2018 Elsevier B.V. All rights reserved.

The potential source of lead in the Permian Kupferschiefer bed of Europe and some selected Paleozoic mineral deposits in the Federal Republic of Germany

USGS Publications Warehouse

Wedepohl, K.H.; Delevaux, M.H.; Doe, B.R.

1978-01-01

New lead isotopic compositions have been measured for Paleozoic bedded and vein ore deposits of Europe by the high precision thermal emission (triple filament) technique. Eleven samples have been analyzed from the Upper Permian Kupferschiefer bed with representatives from Poland to England, three samples from the Middle Devonian Rammelsberg deposit and one from the Middle Devonian Meggen deposit, both of which are conformable ore lenses and are in the Federal Republic of Germany (FRG); and also two vein deposits from the FRG were analyzed, from Ramsbeck in Devonian host rocks and from Grund in Carboniferous host rocks. For Kupferschiefer bed samples from Germany, the mineralization is of variable lead isotopic composition and appears to have been derived about 250 m.y. ago from 1700 m.y. old sources, or detritus of this age, in Paleozoic sedimentary rocks. Samples from England, Holland, and Poland have different isotopic characteristics from the German samples, indicative of significantly different source material (perhaps older). The isotopic variability of the samples from the Kupferschiefer bed in Germany probably favors the lead containing waters coming from shoreward (where poor mixing is to be expected) rather than basinward (where better mixing is likely) directions. The data thus support the interpretation of the metal source already given by Wedepohl in 1964. Data on samples from Rammelsberg and Meggen tend to be slightly less radiogenic than for the Kupferschiefer, about the amount expected if the leads were all derived from the same source material but 100 to 150 m.y. apart in time. The vein galena from Ramsbeck is similar to that from Rammelsberg conformable ore lenses, both in rocks of Devonian age; vein galena from Grund in Upper Carboniferous country rocks is similar to some bedded Kupferschiefer mineralization in Permian rocks, as if the lead composition was formed at about the same time and from similar source material as the bedded deposits. Although heat has played a more significant role in the formation of some of these deposits (veins and Rammelsberg-Meggen) than in others (Kupferschiefer), there is no indication of radically different sources for the lead, all apparently coming from sedimentary source material containing Precambrian detritus. One feldspar lead sample from the Brocken-Oker Granite is not the same in isotopic composition as any of the ores analyzed. ?? 1978 Springer-Verlag.

Own- and Other-Race Face Identity Recognition in Children: The Effects of Pose and Feature Composition

ERIC Educational Resources Information Center

Anzures, Gizelle; Kelly, David J.; Pascalis, Olivier; Quinn, Paul C.; Slater, Alan M.; de Viviés, Xavier; Lee, Kang

2014-01-01

We used a matching-to-sample task and manipulated facial pose and feature composition to examine the other-race effect (ORE) in face identity recognition between 5 and 10 years of age. Overall, the present findings provide a genuine measure of own- and other-race face identity recognition in children that is independent of photographic and image…

The Genesis of Precious and Base Metal Mineralization at the Miguel Auza Deposit, Zacatecas, Mexico

NASA Astrophysics Data System (ADS)

Findley, A. A.; Olivo, G. R.; Godin, L.

2009-05-01

The Miguel Auza mine located in Zacatecas State, Mexico, is a vein-type polymetallic epithermal deposit hosted in deformed argillite, siltstone and, greywacke of the Cretaceous Caracol Formation. Silver-rich base metal veins (0.2 m to >1.5 m wide) are spatially associated with the NE-striking, steeply SE- dipping (70-80°) Miguel Auza fault over a strike length of 1.6 km and a depth of 460 m. A 2 km2 monzonitic stock located in the proximity of the mineralized zones, has previously been interpreted as the source of the mineralizing fluids. Four distinct structural stages are correlated with hydrothermal mineral deposition: (I) The Pre-ore stage is characterized by normal faulting, fracturing of host rock, and rotation of bedding planes. This stage consists of quartz, illite, chlorite, +/- pyrite alteration of sedimentary wall rocks. (II) The Pyrite-vein stage is associated with reverse-sense reactivation of early normal faults, dilation of bedding planes/fractures, and deposition of generally barren calcite + pyrite veinlets. (III) The Main-ore stage is related to the development of reverse-fault- hosted massive sulphide veins. During this stage three phases of mineral deposition are recorded: early pyrite and arsenopyrite, intermediate chalcopyrite, pyrite, arsenopyrite, and base metals, and late base metals and Ag-bearing minerals. Associated gangue minerals during the main ore stage are quartz, muscovite, calcite and chlorite. (IV) The Post-ore stage involves late NW-SE striking block faulting, brecciation and calcite veining. Later supergene oxidation of veins led to deposition of Fe-oxides and hydroxides, commonly filling fractures or replacing early-formed sulphide assemblages. The various vein types display classic epithermal textures including open space filling, banding, comb quartz and brecciation. The Ag-bearing minerals comprise pyrargyrite [Ag3(Sb,As)S3], argentotennantite [(Cu,Ag)10(Zn,Fe)2(Sn,As)4S13], polybasite-pearceite [(Ag,Cu)16(Sb,As)2S11], and acanthite [AgS2]; associated sulphides include galena, sphalerite, chalcopyrite, arsenopyrite and pyrite. In the main ore zone, base metal sulphides are commonly intergrown with the Ag-bearing sulfosalts. Analyses of galena show no significant silver values indicating that silver grades are exclusively associated with the Ag-bearing sulfosalts and sulphides. The distribution of the Sb/(Sb + As) ratios in the silver sulfosalts indicate that the ore forming fluid(s) was consistently antimony-rich during the Ag-rich ore deposition with no significant variation laterally, vertically, or along strike of the vein systems. However, Ag/(Ag + Cu) values in argentotennantite decrease along-strike from NE to SW and with depth. Compositions of argentotennantite + pyrargyrite + sphalerite indicate a primary depositional temperature around 325-350° C for the late phase of the Main-ore stage. Compositions of sphalerite also show an increasing trend in FeS (mol %) along strike of the deposit from NE to SW. The geometric relationship between the various structures, vein types, and the regional Miguel Auza fault zone suggest episodic reverse-sense reactivation of normal faults. It is argued that the structural evolution of the area, and, in particular, the Main-ore stage, provided transport pathways for metal-rich fluids and controlled the orientations of ore-bearing veins. Variations in mineral chemistry suggest that the rocks in the NE sector interacted with hotter fluids than in the SW part of the deposit.

Degradation of different elastomeric polymers in simulated geothermal environments at 300°C

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

Sugama, Toshifumi; Pyatina, Tatiana; Redline, Erica Marie

This study evaluates the degradation of six different elastomeric polymers used for O-rings: EPDM, FEPM, type I- and II-FKM, FFKM, and FSR, in five different simulated geothermal environments at 300 °C: 1) non-aerated steam/cooling cycles, 2) aerated steam/cooling cycles, 3) water-based drilling fluid, 4) CO 2-rich geo-brine fluid, and, 5) heat–cool water quenching cycles. The factors assessed included the extent of oxidation, changes in thermal behavior, micro-defects, permeation of ionic species from the test environments into the O-rings, silicate-related scale-deposition, and changes in the O-rings' elastic modulus. The reliability of the O-rings to maintain their integrity depended on the elastomericmore » polymer composition and the exposure environment. FSR disintegrated while EPDM was oxidized only to some degree in all the environments, FKM withstood heat-water quenching but underwent chemical degradation, FEPM survived in all the environments with the exception of heat-water quenching where it underwent severe oxidation-induced degradation, and FFKM displayed outstanding compatibility with all the tested environments. This study discusses the degradation mechanisms of the polymers under the aforementioned conditions.« less

Degradation of different elastomeric polymers in simulated geothermal environments at 300°C

DOE PAGES

Sugama, Toshifumi; Pyatina, Tatiana; Redline, Erica Marie; ...

2015-07-17

This study evaluates the degradation of six different elastomeric polymers used for O-rings: EPDM, FEPM, type I- and II-FKM, FFKM, and FSR, in five different simulated geothermal environments at 300 °C: 1) non-aerated steam/cooling cycles, 2) aerated steam/cooling cycles, 3) water-based drilling fluid, 4) CO 2-rich geo-brine fluid, and, 5) heat–cool water quenching cycles. The factors assessed included the extent of oxidation, changes in thermal behavior, micro-defects, permeation of ionic species from the test environments into the O-rings, silicate-related scale-deposition, and changes in the O-rings' elastic modulus. The reliability of the O-rings to maintain their integrity depended on the elastomericmore » polymer composition and the exposure environment. FSR disintegrated while EPDM was oxidized only to some degree in all the environments, FKM withstood heat-water quenching but underwent chemical degradation, FEPM survived in all the environments with the exception of heat-water quenching where it underwent severe oxidation-induced degradation, and FFKM displayed outstanding compatibility with all the tested environments. This study discusses the degradation mechanisms of the polymers under the aforementioned conditions.« less

Upgrading nickel content of limonite nickel ore through pelletization, selective reduction and magnetic separation

NASA Astrophysics Data System (ADS)

Mayangsari, W.; Prasetyo, A. B.; Prasetiyo, Puguh

2018-04-01

Limonite nickel ore has potency to utilize as raw material for ferronickel or nickel matte, since it has low grade nickel content, thus process development is needed to find the acceptable process for upgrading nickel. The aim of this research is to determine upgrading of Ni content as result of selective reduction of limonite nickel pellet continued by magnetic separation as effect of temperature and time reduction as well as coal and CaSO4 addition. There are four steps to perform this research, such as preparation including characterization of raw ore and pelletization, selective reduction, magnetic separation and characterization of products by using AAS, XRD and SEM. Based on the result study, pellet form can upgrade 77.78% higher than powder form. Upgrading of Ni and Fe content was up to 3fold and 1.5fold respectively from raw ore used when reduced at 1100°C for 60 minutes with composition of coal and CaSO4, both 10%. The excess of CaSO4 addition caused fayalite formation. Moreover, S2 from CaSO4 also support to reach low melting point and enlardge particle size of metal formed.

Rare-Earth Elements from Modern Mineral-Organic Associations in the Zone of Sulfide Ore Hypergenesis

NASA Astrophysics Data System (ADS)

Vakh, E. A.; Vakh, A. S.; Petukhov, V. I.; Barinov, N. N.

2018-01-01

The REE composition of modern mineral-organic associations in the sulfide ore hypergenesis zone of the Berezitovoe deposit in the Russian Far East was studied for the first time. It is shown that the mineral-organic associations widely abundant in the valley of Konstantinovskii Creek and represented by bright brown crusts on the surface of deluvial deposits were formed at the expense of the influence of acid highly mineralized mine waters from the Berezitovoe deposit. The mineral-organic associations found in the Creek valley may be considered as a new indicator for evaluation of the geoecological state of modern technogenic landscapes.

Effects of pyrite and sphalerite on population compositions, dynamics and copper extraction efficiency in chalcopyrite bioleaching process.

PubMed

Xiao, Yunhua; Liu, Xueduan; Dong, Weiling; Liang, Yili; Niu, Jiaojiao; Gu, Yabing; Ma, Liyuan; Hao, Xiaodong; Zhang, Xian; Xu, Zhen; Yin, Huaqun

2017-07-01

This study used an artificial microbial community with four known moderately thermophilic acidophiles (three bacteria including Acidithiobacillus caldus S1, Sulfobacillus thermosulfidooxidans ST and Leptospirillum ferriphilum YSK, and one archaea, Ferroplasma thermophilum L1) to explore the variation of microbial community structure, composition, dynamics and function (e.g., copper extraction efficiency) in chalcopyrite bioleaching (C) systems with additions of pyrite (CP) or sphalerite (CS). The community compositions and dynamics in the solution and on the ore surface were investigated by real-time quantitative PCR (qPCR). The results showed that the addition of pyrite or sphalerite changed the microbial community composition and dynamics dramatically during the chalcopyrite bioleaching process. For example, A. caldus (above 60%) was the dominant species at the initial stage in three groups, and at the middle stage, still dominated C group (above 70%), but it was replaced by L. ferriphilum (above 60%) in CP and CS groups; at the final stage, L. ferriphilum dominated C group, while F. thermophilum dominated CP group on the ore surface. Furthermore, the additions of pyrite or sphalerite both made the increase of redox potential (ORP) and the concentrations of Fe 3+ and H + , which would affect the microbial community compositions and copper extraction efficiency. Additionally, pyrite could enhance copper extraction efficiency (e.g., improving around 13.2% on day 6) during chalcopyrite bioleaching; on the contrary, sphalerite restrained it.

Formation of Si-Al-Mg-Ca-rich zoned magnetite in an end-Permian phreatomagmatic pipe in the Tunguska Basin, East Siberia

NASA Astrophysics Data System (ADS)

Neumann, Else-Ragnhild; Svensen, Henrik H.; Polozov, Alexander G.; Hammer, Øyvind

2017-12-01

Magma-sediment interactions in the evaporite-rich Tunguska Basin resulted in the formation of numerous phreatomagmatic pipes during emplacement of the Siberian Traps. The pipes contain magnetite-apatite deposits with copper and celestine mineralization. We have performed a detailed petrographic and geochemical study of magnetite from long cores drilled through three pipe breccia structures near Bratsk, East Siberia. The magnetite samples are zoned and rich in Si (≤5.3 wt% SiO2), Ca, Al, and Mg. They exhibit four textural types: (1) massive ore in veins, (2) coating on breccia clasts, (3) replacement ore, and (4) reworked ore at the crater base. The textural types have different chemical characteristics. "Breccia coating" magnetite has relatively low Mg content relative to Si, as compared to the other groups, and appears to have formed at lower oxygen fugacity. Time series analyses of MgO variations in microprobe transects across Si-bearing magnetite in massive ore indicate that oscillatory zoning in the massive ore was controlled by an internal self-organized process. We suggest that hydrothermal Fe-rich brines were supplied from basalt-sediment interaction zones in the evaporite-rich sedimentary basin, leading to magnetite ore deposition in the pipes. Hydrothermal fluid composition appears to be controlled by proximity to dolerite fragments, temperature, and oxygen fugacity. Magnetite from the pipes has attributes of iron oxide-apatite deposits (e.g., textures, oscillatory zoning, association with apatite, and high Si content) but has higher Mg and Ca content and different mineral assemblages. These features are similar to magnetite found in skarn deposits. We conclude that the Siberian Traps-related pipe magnetite deposit gives insight into the metamorphic and hydrothermal effects following magma emplacement in a sedimentary basin.

Metamorphic ore remobilization in the Hällefors district, Bergslagen, Sweden: constraints from mineralogical and small-scale sulphur isotope studies

NASA Astrophysics Data System (ADS)

Wagner, Thomas; Jonsson, Erik; Boyce, Adrian J.

2005-07-01

The marble- and metavolcanic-hosted Pb Zn (Ag Sb As) deposits of the Hällefors district, located in the Palaeoproterozoic Bergslagen ore province, south central Sweden, comprise both stratabound sulphides and discordant, Ag-rich sulphide sulphosalt veins. The complex sulphide sulphosalt assemblages of the Alfrida-Jan Olof mines at Hällefors were investigated by a combination of ore microscopy, electron-microprobe analysis, and in situ laser sulphur isotope analysis. The massive ore is characterized by positive and homogeneous δ34S (+1.4‰ to +2.7‰ V-CDT), whereas vein-hosted sulphides and sulphosalts exhibit similar, but generally less positive to slightly negative δ34S (-0.6‰ to +2.0‰). Comparison of the observed ore mineral assemblages with calculated phase equilibria in the system Fe As S O H and isotopic fractionation as a function of temperature, oxygen fugacity and pH indicates that the vein-type mineralization was formed from relatively reduced and rather alkaline hydrothermal fluids. At these reduced conditions, fractionation of δ34S via changes of fO2 is insignificant, and thus the isotopic signatures of the vein minerals directly reflect the composition of the sulphur source. We therefore conclude that the vein-type ore essentially inherited the sulphur isotope signature from the pre-existing massive sulphides via metamorphic remobilization at approximately 300 400°C and 2 3 kbar. Scales of remobilization observable are on the order of about 5 mm to 30 cm. Overall, the sulphide sulphosalt assemblages from the Alfrida-Jan Olof mines exhibit δ34S values which are comparable to a majority of metasupracrustal-hosted deposits in the Bergslagen province, thereby suggesting a common origin from ca. 1.90 1.88 Ga volcanic-hydrothermal processes.

The Krásná Hora, Milešov, and Příčovy Sb-Au ore deposits, Bohemian Massif: mineralogy, fluid inclusions, and stable isotope constraints on the deposit formation

NASA Astrophysics Data System (ADS)

Němec, Matěj; Zachariáš, Jiří

2018-02-01

The Krásná Hora-Milešov and Příčovy districts (Czech Republic) are the unique examples of Sb-Au subtype orogenic gold deposits in the Bohemian Massif. They are represented by quartz-stibnite veins and massive stibnite lenses grading into low-grade, disseminated ores in altered host rocks. Gold postdates the stibnite and is often replaced by aurostibite. The ore zones are hosted by hydrothermally altered dikes of lamprophyres (Krásná Hora-Milešov) or are associated with local strike-slip faults (Příčovy). Formation of Sb-Au deposits probably occurred shortly after the main gold-bearing event (348-338 Ma; Au-only deposits) in the central part of the Bohemian Massif. Fluid inclusion analyses suggest that stibnite precipitated at 250 to 130 °C and gold at 200 to 130 °C from low-salinity aqueous fluids. The main quartz gangue hosting the ore precipitated from the same type of fluid at about 300 °C. Early quartz-arsenopyrite veins are not associated with the Sb-Au deposition and formed from low-salinity, aqueous-carbonic fluid at higher pressure and temperature ( 250 MPa, 400 °C). The estimated oxygen isotope composition of the ore-bearing fluid (4 ± 1‰ SMOW; based on post-ore calcite) suggests its metamorphic or mixed magmatic-metamorphic origin and excludes the involvement of meteoric water. Rapid cooling of warm hydrothermal fluids reacting with "cold" host rock was probably the most important factor in the formation of both stibnite and gold.

Geochronology, petrogenesis and tectonic settings of pre- and syn-ore granites from the W-Mo deposits (East Kounrad, Zhanet and Akshatau), Central Kazakhstan

NASA Astrophysics Data System (ADS)

Li, GuangMing; Cao, MingJian; Qin, KeZhang; Evans, Noreen J.; Hollings, Pete; Seitmuratova, Eleonora Yusupovha

2016-05-01

There is significant debate regarding the mineralization ages of the East Kounrad, Zhanet and Akshatau W-Mo deposits of Central Kazakhstan, and the petrogenesis and tectono-magmatic evolution of the granites associated with these deposits. To address these issues, we present molybdenite Re-Os dating, zircon U-Pb dating, whole rock geochemistry as well as Sr-Nd-Pb and zircon O-Hf isotopic analyses on the pre-mineralization and ore-forming granites. U-Pb dating of zircons from pre-mineralization granitic rocks yield Late Carboniferous ages of 320-309 Ma, whereas ore-forming granites have Early Permian ages of 298-285 Ma. Molybdenite Re-Os isotopic data indicate a mineralization age of 296 Ma at East Kounrad, 294 Ma at Akshatau and 285 Ma at Zhanet. The pre-ore and ore-forming granites are high-K calc-alkaline, metaluminous to slightly peraluminous I-type granites. The pre-mineralization granites are relatively unfractionated, whereas the ore-forming granites are highly fractionated. The fractionating mineral phases are probably K-feldspar, apatite, Ti-bearing phases and minor plagioclase. The pre-mineralization and ore-forming rocks are characterized by similar Sr-Nd-Pb-Hf-O isotopic compositions ((87Sr/86Sr)i = 0.70308-0.70501, εNd (t) = - 0.5 to + 2.8, 207Pb/204Pb = 15.60-15.82, zircon εHf (t) = + 1.2 to + 15.6 and δ18O = + 4.6 to + 10.3‰), whole rock TDMC (Nd) (840-1120 Ma) and zircon TDMC (Hf) (320-1240 Ma). The isotopic characteristics are consistent with a hybrid magma source caused by 10-30% assimilation of ancient crust by juvenile lower crust. The geochronology and geochemistry of these granites show that the Late Carboniferous pre-mineralization granitic rocks formed during subduction, whereas the Early Permian ore-forming, highly fractionated granite probably underwent significant fractionation with a restite assemblage of K-feldspar, apatite, Ti-bearing phases and minor plagioclase and developed during collision between the Yili and Kazakhstan terranes commenced at the latest Late Carboniferous.

Geologic setting, genesis and transformation of sulfide deposits in the northern part of Khetri copper belt, Rajasthan, India — an outline

NASA Astrophysics Data System (ADS)

Sarkar, S. C.; Dasgupta, Somnath

1980-07-01

The present study is confined to the northern part of the Khetri copper belt that extends for about 100 km in northern Rajasthan. Mineralization is more or less strata-bound and is confined to the garnetiferous chlorite schist and banded amphibolite quartzite, occurring towards the middle of the Proterozoic Delhi Supergroup. Preserved sedimentary features and re-estimation of the composition of the pre-metamorphic rocks suggest that the latter were deposited in shallow marine environment characterized by tidal activity. Cordierite-orthoamphibole-cummingtonite rock occurring in the neighbourhood of the ores is discussed, and is suggested to be isochemically metamorphosed sediment. The rocks together with the ores were deformed in two phases and metamorphosed in two progressive and one retrogressive events of metamorphism. Study of the host rocks suggests that the maximum temperature and pressure attained during metamorphism are respectively 550 600°C and < 5.5 kb. Principal ore minerals in Madan Kudan are chalcopyrite, pyrrhotite, pyrite and locally magnetite. In Kolihan these are chalcophyrite, pyrrhotite and cubanite. Subordinate phases are sphalerite, ilmenite, arsenopyrite, mackinawite, molybdenite, cobaltite and pentlandite. The last two are very rare. Gangue minerals comprise quartz, chlorite, garnet, amphiboles, biotite, scapolite, plagioclase and graphite. The ores are metamorphosed at temperatures > 491°C. Sulfide assemblages are explained in terms of fS 2 during metamorphism. Co-folding of the ore zone with the host rocks, confinement of the ores to the carbonaceous pelites or semi-pelitic rocks, strata-bound and locally even stratiform nature of the orebodies, lack of finite ‘wall rock alteration’, metamorphism of the ores in the thermal range similar to that for the host rocks, absence of spatial and temporal relationship with the granitic rocks of the region led the authors to conclude that the entire mineralization was originally sedimentary-diagenetic. Any loss of primitive features and development of incongruency are due to subsequent deformation and metamorphism to which the ores and their hosts were together subjected.

The origin of the Tongkeng-Changpo tin deposit, Dachang metal district, Guangxi, China: clues from fluid inclusions and He isotope systematics

NASA Astrophysics Data System (ADS)

Minghai, Cai; Jingwen, Mao; Ting, Liang; Pirajno, Franco; Huilan, Huang

2007-08-01

Tongkeng-Changpo is the largest tin deposit within the giant Dachang polymetallic tin ore field in Guangxi, southern China, which is part of a large skarn system associated with Cretaceous granitoids. The Tongkeng-Changpo mineralization consists of veins and stockworks in the upper levels and replacement stratiform orebodies (mantos) at lower levels. Based on textural relationships, three major mineralizing stages can be recognized: stage I with cassiterite, sulphides, stannite, tourmaline, and quartz; stage II with cassiterite, sulphides, sulphosalts, quartz, and calcite; and stage III with calcite as the main phase. The study of fluid inclusions has shown that there are two main fluid types: CO2 and NaCl-H2O. Homogenization temperatures are 270 to 365°C, 210 to 240°C, and 140 to 190°C for stages I, II, and III, respectively. Salinities range from 1 to 7 wt.% NaCl equiv. in the early ore stage and 3 to 10 wt.% NaCl equiv. in the late stages. Laser Raman Spectroscopy indicates that the inclusion fluids in stages I and II were of carbono-aqueous composition, with minor amounts of CH4 and H2S, whereas those in stage III were aqueous. Helium isotopic analyses of inclusion fluids indicate that the 3He/4He ratios in the ore veins are in between 1.2 to 2.9 Ra (Ra = 1.4 × 10-6, modern atmospheric ratio), and range from 1.6 to 2.5 Ra in the stratiform orebodies. This range of 3He/4He ratios is significantly higher than that of crustal fluids (0.01-0.05 Ra). The similar characteristics of fluid inclusions and their He isotopic composition, as well as age constraints, indicate that the ore veins and stratiform orebodies of the Tongkeng-Changpo deposit formed from the same hydrothermal system, likely related to granite intrusions of the Mesozoic Yanshanian tectono-thermal event. In addition, the high R/Ra ratios indicate a mantle contribution in the ore fluids.

Own- and other-race face identity recognition in children: the effects of pose and feature composition.

PubMed

Anzures, Gizelle; Kelly, David J; Pascalis, Olivier; Quinn, Paul C; Slater, Alan M; de Viviés, Xavier; Lee, Kang

2014-02-01

We used a matching-to-sample task and manipulated facial pose and feature composition to examine the other-race effect (ORE) in face identity recognition between 5 and 10 years of age. Overall, the present findings provide a genuine measure of own- and other-race face identity recognition in children that is independent of photographic and image processing. The current study also confirms the presence of an ORE in children as young as 5 years of age using a recognition paradigm that is sensitive to their developing cognitive abilities. In addition, the present findings show that with age, increasing experience with familiar classes of own-race faces and further lack of experience with unfamiliar classes of other-race faces serves to maintain the ORE between 5 and 10 years of age rather than exacerbate the effect. All age groups also showed a differential effect of stimulus facial pose in their recognition of the internal regions of own- and other-race faces. Own-race inner faces were remembered best when three-quarter poses were used during familiarization and frontal poses were used during the recognition test. In contrast, other-race inner faces were remembered best when frontal poses were used during familiarization and three-quarter poses were used during the recognition test. Thus, children encode and/or retrieve own- and other-race faces from memory in qualitatively different ways.

Own- and other-race face identity recognition in children: The effects of pose and feature composition

PubMed Central

Anzures, Gizelle; Kelly, David J.; Pascalis, Olivier; Quinn, Paul C.; Slater, Alan M.; de Viviés, Xavier; Lee, Kang

2013-01-01

We used a matching-to-sample task and manipulated facial pose and feature composition to examine the other-race effect (ORE) in face identity recognition between 5 and 10 years of age. Overall, the present findings provide a genuine measure of own- and other-race face identity recognition in children that is independent of photographic and image processing. The present study also confirms the presence of an ORE in children as young as 5 years of age using a recognition paradigm that is sensitive to their developing cognitive abilities. In addition, the present findings show that with age, increasing experience with familiar classes of own-race faces and further lack of experience with unfamiliar classes of other-race faces serves to maintain the ORE between 5 to 10 years of age rather than exacerbate the effect. All age groups also showed a differential effect of stimulus facial pose in their recognition of the internal regions of own- and other-race faces. Own-race inner faces were remembered best when three-quarter poses were used during familiarization and frontal poses were used during the recognition test. In contrast, other-race inner faces were remembered best when frontal poses were used during familiarization and three-quarter poses were used during the recognition test. Thus, children encode and/or retrieve own- and other-race faces from memory in qualitatively different ways. PMID:23731287

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

Mcwilliams, A. J.; Daugherty, W. L.; Skidmore, T. E.

The 9975 Type B shipping package is used within the DOE complex for shipping special nuclear materials. This package is re-certified annually in accordance with Safety Analysis Report for Packaging (SARP) requirements. The package is also used at the Savannah River Site as part of the long-term storage configuration of special nuclear materials. As such, the packages do not undergo annual recertification during storage, with uncertainty as to how long some of the package components will meet their functional requirements in the storage environment. The packages are currently approved for up to 15 years storage, and work continues to providemore » a technical basis to extend that period. This report describes efforts by the Savannah River National Laboratory (SRNL) to extend the service life estimate of Viton® GLT and GLT-S fluoroelastomer O-rings used in the 9975 shipping package. O-rings of both GLT and GLT-S compositions are undergoing accelerated aging at elevated temperature, and are periodically tested for compression stress relaxation (CSR) behavior. The CSR behavior of O-rings was evaluated at temperatures from 175 to 400 °F. These collective data were used to develop predictive models for extrapolation of CSR behavior to relevant service temperatures (< 156 °F). The predictive model developed from the CSR data conservatively indicates a service life of approximately 37 years for Viton GLT O-rings at the maximum effective service temperature of 156 °F. The estimated service life for Viton GLT-S O-rings is significantly longer.« less

A mineralogical perspective on the recovery of platinum group elements from Merensky Reef and UG2 at the Two Rivers mine on the Eastern limb of the Bushveld Complex in South Africa

NASA Astrophysics Data System (ADS)

Rose, Derek H.; Viljoen, K. S.; Mulaba-Bafubiandi, Antoine

2018-06-01

Published studies dealing with the process mineralogy of Pt mines on the Bushveld Complex is generally limited to the Western Bushveld. The recognition by mine management that another resource, in addition to the Upper Group 2 (UG2) reef currently being mined at the Two Rivers platinum mine (TRP), is urgently required in order to extend the life of mine, presented an opportunity to conduct such a study on the Eastern Limb of the Bushveld Complex. A process mineralogical investigation was undertaken on ore from the Merensky Reef (MR) and the UG2 at TRP. This was conducted on a suite of geological samples (channel samples) collected from the underground workings, as well as metallurgical samples obtained from the rougher circuits at the concentrator plant during the processing of MR and UG2 ore. The geological and metallurgical samples were analysed for bulk composition and quantitative mineralogy, while the geological samples were also subjected to laboratory-scale milling and flotation tests. This study shows that, although mineralogically distinct, the MR and UG2 behave similarly in terms of metallurgical performance. This holds promise for the proposed blending of MR and UG2 ores at TRP. An evaluation of the bulk rock (ore) Pt/Pd ratio as a possible indicator of the level of hydrothermal alteration of the ore, demonstrates that this may be of use in predicting recovery plant performance.

Manipulation of a Senescence-Associated Gene Improves Fleshy Fruit Yield1[OPEN

PubMed Central

Gramegna, Giovanna; Trench, Bruna A.; Alves, Frederico R.R.; Silva, Eder M.; Silva, Geraldo F.F.; Thirumalaikumar, Venkatesh P.; Lupi, Alessandra C.D.; Demarco, Diego; Nogueira, Fabio T.S.; Freschi, Luciano

2017-01-01

Senescence is the process that marks the end of a leaf’s lifespan. As it progresses, the massive macromolecular catabolism dismantles the chloroplasts and, consequently, decreases the photosynthetic capacity of these organs. Thus, senescence manipulation is a strategy to improve plant yield by extending the leaf’s photosynthetically active window of time. However, it remains to be addressed if this approach can improve fleshy fruit production and nutritional quality. One way to delay senescence initiation is by regulating key transcription factors (TFs) involved in triggering this process, such as the NAC TF ORESARA1 (ORE1). Here, three senescence-related NAC TFs from tomato (Solanum lycopersicum) were identified, namely SlORE1S02, SlORE1S03, and SlORE1S06. All three genes were shown to be responsive to senescence-inducing stimuli and posttranscriptionally regulated by the microRNA miR164. Moreover, the encoded proteins interacted physically with the chloroplast maintenance-related TF SlGLKs. This characterization led to the selection of a putative tomato ORE1 as target gene for RNA interference knockdown. Transgenic lines showed delayed senescence and enhanced carbon assimilation that, ultimately, increased the number of fruits and their total soluble solid content. Additionally, the fruit nutraceutical composition was enhanced. In conclusion, these data provide robust evidence that the manipulation of leaf senescence is an effective strategy for yield improvement in fleshy fruit-bearing species. PMID:28710129

A Late Variscan Sn province: the Arburese region (SW Sardinia, Italy)

NASA Astrophysics Data System (ADS)

Naitza, Stefano; Secchi, Francesco; Oggiano, Giacomo; Cuccuru, Stefano

2015-04-01

Late Variscan Sn - rich European provinces (e. g. Erzgebirge, Cornwall) are of particular relevance as they offer key insights into crustal evolution, intrusive processes and ore genesis. In Sardinia (Italy), small Sn deposits are only known in the Arburese historical mining region (SW Sardinia), hosted in low-grade metamorphics close to the contacts with intrusives. This region is characterised by two late variscan intrusions, which differ in age and composition: the Arbus and the Monte Linas pluton, aging 304 ± 1 Ma, and 289 ± 1 Ma respectively. They emplaced at shallow crustal levels and crosscut the basal thrust between the alloctonous prism and the foreland of the Variscan belt of Sardinia. The Arbus Pluton (AP) is a composite intrusion of piroxene- and amphibole- granodiorites hosting minor amounts of monzogabbroic rocks and cordierite-bearing granites with a wide core of leuco-monzogranites. Tourmaline greisens and pegmatites garnish the contact between the border facies and the host metamorphic rocks. The Monte Linas Pluton (MLP) has biotite monzogranite composition. The pluton is internally zoned, from medium grained monzogranite in the core to hololeucocratic fine-grained rock-types at the top, where often F-greisen, fayalite-pegmatite pods and sill are common. In both plutons the igneous associations are high-K ilmenite series, suggesting derivation from low- fO2 magmas possibly linked to a common crustal contribution; however, in the Linas Pluton magnetite in the fine-grained facies may indicate an increase in oxygen fugacity. The AP-related Sn ores consist of high-temperature As-Sn quartz veins. They are vertically zoned, from quartz-chlorite-cassiterite to large quartz-arsenopyrite veins. Ore microscopy and SEM-EDS analyses evidenced a vein texture made of thick idiomorphic and frequently twinned cassiterite crystals, alternated with several generations of banded/geodic quartz. Chlinoclore aggregates are included into the quartz. The arsenopyrite ore shows alternating bands of microgranular to crystalline millimetric arsenopyrite with quartz. Field and analytical data suggest genetic mechanisms dominated by mobilization of residual Sn by chloride and other complexes in reducing, As- and S- rich, low- fO2 juvenile fluids. Cassiterite and successive arsenopyrite precipitation occurred under changing physicochemical conditions (e.g. oxygen contents; temperature decrease; pH). The MLP Sn metallogeny include Sn- Pb-Zn-Cu veins (Canale Serci old mine). Cassiterite occurs as fine-grained corroded crystals. Optical and SEM-EDS analyses evidence a high-temperature oxide stage (quartz-chlorite- cassiterite) followed, after brecciation, by mesothermal sulfide stages, with progressive deposition of sphalerite, pyrite, chalcopyrite, tetrahedrite, galena, marcasite. Arsenopyrite is strikingly absent. These evidences indicate possible derivation of the ore from residual, reducing juvenile fluids, capable to carry Sn- complexes from monzogranite magmas from which cassiterite precipitated in consequence of an increasing in fO2. Despite their limited amount, the Sn ores of SW Sardinia have high metallogenic relevance, indicating the persistence, of geochemical conditions,which lasted 15 Ma, favorable to the genesis of a Sn metallogenic province.

Compositional and isotopic heterogeneities in the Neo-Tethyan upper mantle recorded by coexisting Al-rich and Cr-rich chromitites in the Purang peridotite massif, SW Tibet (China)

NASA Astrophysics Data System (ADS)

Xiong, Fahui; Yang, Jingsui; Xu, Xiangzhen; Kapsiotis, Argyrios; Hao, Xiaolin; Liu, Zhao

2018-06-01

The Purang harzburgite massif in SW Tibet (China) hosts abundant chrome ore deposits. Ores consist of 20 to >95% modal chromian spinel (Cr-spinel) with mylonitic fabric in imbricate shaped pods. The composition of Cr-spinel in these ores ranges from Al-rich [Cr#Sp or Cr/(Cr + Al) × 100 = 47.60-57.56] to Cr-rich (Cr#Sp: 62.55-79.57). Bulk platinum-group element (PGE) contents of chromitites are also highly variable ranging from 17.5 ppb to ∼2.5 ppm. Both metallurgical and refractory chromitites show a general enrichment in the IPGE (Os, Ir and Ru) with respect to the PPGE (Rh, Pt and Pd), resulting mostly in right-sloping primitive mantle (PM)-normalized PGE profiles. The platinum-group mineral (PGM) assemblages of both chromitite types are dominated by heterogeneously distributed, euhedral Os-bearing laurite inclusions in Cr-spinel. The Purang chromitites have quite inhomogeneous 187Os/188Os ratios (0.12289-0.13194) that are within the range of those reported for mantle-hosted chromitites from other peridotite massifs. Geochemical calculations demonstrate that the parental melts of high-Cr chromitites were boninitic, whereas those of high-Al chromitites had an arc-type tholeiitic affinity. Chromite crystallization was most likely stimulated by changes in magma compositions due to melt-peridotite interaction, leading to the establishment of a heterogeneous physicochemical environment during the early crystallization of the PGM. The highly variable PGE contents, inhomogeneous Os-isotopic compositions and varying Cr#Sp ratios of these chromitites imply a polygenetic origin for them from spatially distinct melt inputs. The generally low γOs values (<1) of chromitites indicate that their parental melts originated within different sections of a heterogeneously depleted mantle source region. These melts were most likely produced in the mantle wedge above a downgoing lithospheric slab.

Eddy-Current Monitoring Of Composite Layups

NASA Technical Reports Server (NTRS)

Fox, Robert L.; Buckley, John D.

1993-01-01

Eddy-current-probe apparatus used to determine predominant orientations of fibers in fiber/matrix composite materials. Apparatus nondestructive, noninvasive means for monitoring composite prepregs and layups during fabrication to ensure predictable and repeatable mechanical properties of finished composite panels. Consists essentially of electromagnet coil wrapped around horseshoe-shaped powdered-iron or ferrite ore. Optionally, capacitor included in series or parallel with coil to form resonant circuit. Impedance monitor excites radio-frequency current in coil and measures impedance of probe circuit. Affected by whatever material placed near ends of core, where material intercepts alternating magnetic field excited in core by current in coil.

Geologic setting and genesis of the Mule Canyon low-sulfidation epithermal gold-silver deposit, north-central Nevada

USGS Publications Warehouse

John, D.A.; Hofstra, A.H.; Fleck, R.J.; Brummer, J.E.; Saderholm, E.C.

2003-01-01

The Mule Canyon mine exploited shallow, low-sulfidation, epithermal Au-Ag deposits that lie near the west side of the Northern Nevada rift in northern Lander County, Nevada. Mule Canyon consists of six small deposits that contained premining reserves of about 8.2 Mt at an average grade of 3.81 g Au/tonne. It is an uncommon mafic end member of low-sulfidation Au-Ag deposits associated with tholeiitic bimodal basalt-rhyolite magmatism. The ore is hosted by a basalt-andesite eruptive center that formed between about 16.4 to 15.8 Ma during early mafic eruptions related to regionally extensive bimodal magmatism. Hydrothermal alteration and Au-Ag ores formed at about 15.6 Ma and were tightly controlled by north-northwest- to north-striking high-angle fault and breccia zones developed during rifting, emplacement of mafic dikes, and eruption of mafic lava flows. Hydrothermal alteration assemblages are zoned outward from fluid conduits in the sequence silica-adularia, adularia-smectite, smectite (intermediate argillic), and smectite-carbonate (propylitic). All alteration types contain abundant pyrite and/or marcasite ?? arsenopyrite. Field relations indicate that silica-adularia alteration is superimposed on argillic and propylitic alteration. Little or no steam-heated acid-sulfate alteration is present, probably the result of a near-surface water table during hydrothermal alteration and ore deposition. Two distinct ore types are present at Mule Canyon: early replacement and later open-space filling. Replacement ores consist of disseminated and vesicle-filling pyrite, marcasite, and arsenopyrite in argillically altered or weakly silicified rocks. Ore minerals consist of Au-bearing arsenopyrite and arsenian pyrite overgrowths on earlier-formed pyrite and marcasite. Open-space filling ores include narrow stockwork quartz-adularia veins, banded and crustiform opaline and chalcedonic silica-adularia veins, silica-adularia cemented breccias, and sparse carbonate-pyrite and/or marcasite veins. Ore minerals consist mostly of electrum and Ag sulfide and selenide minerals, with minor to major amounts of pyrite, marcasite, and arsenopyrite, and local stibnite. Both types of ores have similar geochemical signatures, characterized by high Au, Ag, As, Sb, and Se contents, locally high Hg, Mo, Tl, and W contents, and low Cu, Pb, and Zn contents. Stable isotope data indicate that ore fluids consisted dominantly of meteoric water that evolved by deep circulation through Paleozoic sedimentary rocks at low water/rock ratios (about 1) and high temperatures (>200??C). Calculated isotopic compositions of ore fluids are ??18OH2O = -3 to -7 per mil, ??DH2O = -107 to -124 per mil, ??13CCO2 = 0 to -6 per mil, and ??34SH2S = -3 to +8 per mil. The ore fluids obtained much of their H2S and CO2 and probably scavenged ore metals and trace elements from the Paleozoic sedimentary rocks. Some H2S and CO2 may have been derived from degassing Miocene magmas. Mule Canyon formed at shallow depths, probably about 100 m below the paleosurface. Ore fluids were dilute, nearly neutral in pH, reduced, H2S-rich, and CO2-bearing. Peak temperatures in ore zones reached 230?? to 265??C at nearly lithostatic pressures when some crystalline quartz ?? adularia precipitated, but most ore formed at temperatures <200??C at near hydrostatic pressures and was accompanied by precipitation of opaline and chalcedonic silica ?? adularia ?? calcite and dolomite. Deposition of gold in As-rich overgrowths on pyrite and/or marcasite in disseminated ores occurred owing to decreasing H2S in the ore fluids resulting from sulfidation reactions. Later electrum and Ag selenide precipitation in open spaces occurred owing to boiling, loss of H2S to the vapor phase, and cooling. Mule Canyon is similar to most other low-sulfidation Au-Ag deposits associated with Miocene tholeiitic bimodal basalt-rhyolite magmatism in the Great Basin, such as Sleeper, Midas, and Buckhorn. Major differences at Mule Canyon are

Analytical results for total-digestions, EPA-1312 leach, and net acid production for twenty-three abandoned metal-mining related wastes in the Boulder River watershed, northern Jefferson County, Montana

USGS Publications Warehouse

Fey, David L.; Desborough, George A.; Finney, Christopher J.

2000-01-01

IntroductionMetal-mining related wastes in the Boulder River basin study area in northern Jefferson County, Montana, have been implicated in their detrimental effects on water quality with regard to acid generation and toxic-metal solubilization during snow melt and storm water runoff events. This degradation of water quality is defined chiefly by the “Class 1 Aquatic Life Standards” that give limits for certain dissolved metal concentrations according to water alkalinity.Veins enriched in base- and precious metals were explored and mined in the Basin, Cataract Creek, and High Ore Creek drainages over a period of more than 70 years. Extracted minerals included galena, sphalerite, pyrite, chalcopyrite, tetrahedrite and arsenopyrite. Most of the metal-mining wastes in the study area were identified and described by the Montana Bureau of Mines and Geology. In 1997, the U.S. Geological Survey collected 20 composite samples of mine-dump or tailings waste from ten sites in the Basin and Cataract Creek drainages, and two samples from one site in the High Ore Creek drainage. Desborough and Fey presented data concerning acid generation potential, mineralogy, concentrations of certain metals by energy-dispersive X-ray fluorescence (EDXRF), and trace-element leachability of mine and exploration wastes from the ten sites of the Basin and Cataract Creek drainages. The present report presents total-digestion major- and trace-element analyses, net acid production (NAP), and results from the EPA-1312 synthetic precipitation leach procedure (SPLP) performed on the same composite samples from the ten sites from the Basin and Cataract Creek drainages, and two composite samples from the site in the High Ore Creek drainage.

Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

USGS Publications Warehouse

Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

1999-01-01

The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep-ocean waters, and marine transgression. Water depth increased from deposition of the black phyllite sequence through deposition of the Mn mixed-carbonate sequence, then shallowed again during deposition of the overlying dolostone sequence. Bottom waters were mostly dysoxic to suboxic, but fluctuated from oxic to anoxic. Productivity was high during deposition of the black phyllite sequence, increased during precipitation of phosphorite, and then decreased to moderate levels during precipitation of rhodochrostone ores. Biosilica contributions occur in each lithology, but are greatest in rhodochrostone. Changes in sedimentation were determined by changes in water depth, productivity, upwelling, sea-level change, and ventilation of the depositional basin. The source of the phosphorus was organic matter produced in great quantities during deposition of the black phyllite and phosphorite sequences in a zone of coastal upwelling. Organic matter accumulation was rapid. Globally, Mn was supplied by overturn of stagnant, metal-rich deep-ocean waters, which were redistributed to areas of coastal upwelling and seaways; that process may have been initiated by latest Proterozoic glaciations which would have promoted density stratification and accumulation and storage of metals. Regionally, Mn was supplied by terrigenous input into the shallow seaway and hydrothermal input into the deeper water parts of that seaway. Locally, Mn sources included leaching and transport of metals from the sediment column. Manganese was stored locally in low-oxygen (not anoxic) seawater prior to Mn-ore formation. The source of the carbon in the Mn carbonates and dolostones was predominantly seawater bicarbonate and secondarily CO2 derived from the oxidation of organic matter in the bacterially mediated diagenetic zone of sulfate reduction.

Magnetite-apatite-dolomitic rocks of Ust-Chulman (Aldan shield, Russia): Seligdar-type carbonatites?

NASA Astrophysics Data System (ADS)

Prokopyev, Ilya R.; Doroshkevich, Anna G.; Redina, Anna A.; Obukhov, Andrey V.

2018-04-01

The Ust-Chulman apatite ore body is situated within the Nimnyrskaya apatite zone at the Aldan shield in Russia. The latest data confirm the carbonatitic origin of the Seligdar apatite deposit (Prokopyev et al. in Ore Geol Rev 81:296-308, 2017). The results of our investigations demonstrate that the magnetite-apatite-dolomitic rocks of the Ust-Chulman are highly similar to Seligdar-type dolomitic carbonatites in terms of the mineralogy and the fluid regime of formation. The ilmenite and spinel mineral phases occur as solid solutions with magnetite, and support the magmatic origin of the Ust-Chulman ores. The chemical composition of REE- and SO3-bearing apatite crystals and, specifically, monazite-(Ce) mineralisation and the formation of Nb-rutile, late hydrothermal sulphate minerals (barite, anhydrite) and haematite are typical for carbonatite complexes. The fluid inclusions study revealed similarities to the evolutionary trend of the Seligdar carbonatites that included changes of the hydrothermal solutions from highly concentrated chloride to medium-low concentrated chloride-sulphate and oxidized carbonate-ferrous.

Escondida Mine, Chile

NASA Image and Video Library

2001-10-22

This ASTER image covers 30 by 37 km in the Atacama Desert, Chile and was acquired on April 23, 2000. The Escondida Cu-Au-Ag open-pit mine is at an elevation of 3050 m, and came on stream in 1990. Current capacity is 127,000 tons/day of ore; in 1999 production totaled 827,000 tons of copper, 150,000 ounces of gold and 3.53 million ounces of silver. Primary concentration of the ore is done on-site; the concentrate is then sent to the coast for further processing through a 170 km long, 9 pipe. Escondida is related geologically to three porphyry bodies intruded along the Chilean West Fissure Fault System. A high grade supergene cap overlies primary sulfide ore. This image is a conventional 3-2-1 RGB composite. Figure 1 displays SWIR bands 4-6-8 in RGB, and highlights lithologic and alteration differences of surface units. The image is located at 24.3 degrees south latitude and 69.1 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA11090

Effect of temperature in the selective reduction process of limonite nickel ore

NASA Astrophysics Data System (ADS)

Mayangsari, W.; Febriana, Eni; Prasetyo, A. B.

2018-05-01

Temperature is the main factor for the reduction process that influence to reduction degree, phase and morphology transformation. In order to determine these effects which is caused by reduction temperature, this study was conducted. Limoniticnickel ore was prepared by drying and size reduction. A part of prepared limonitewas characterized with XRF to determine the chemical composition. The other part was mixed with reducing agent and CaSO4 to produce pellet. A series of selective reduction processes were conducted to the pellet by using graphite crucible in the muffle furnace carbolite at 800° - 1100°C for 60 minutes. Reduced ore characterized by using XRD and SEM analysis. Based on the result study, weight loss and reduction degree increase as temperature raised along with CaSO4 addition. Moreover, it caused decomposition and transformation to the metallic phase of kamacite and iron up to 7.51% and 41.44% respectively in the reduction process at 1100°C for 60 minutes. Furthermore, particle size growth as metallic phase content increased.

Static Thermochemical Model of COREX Melter Gasifier

NASA Astrophysics Data System (ADS)

Srishilan, C.; Shukla, Ajay Kumar

2018-02-01

COREX is one of the commercial smelting reduction processes. It uses the finer size ore and semi-soft coal instead of metallurgical coke to produce hot metal from iron ore. The use of top gas with high calorific value as a by-product export gas makes the process economical and green. The predictive thermochemical model of the COREX process presented here enables rapid computation of process parameters such as (1) required amount of ore, coal, and flux; (2) amount of slag and gas generated; and (3) gas compositions (based on the raw material and desired hot metal quality). The model helps in predicting the variations in process parameters with respect to the (1) degree of metallization and (2) post-combustion ratio for given raw material conditions. In general reduction in coal, flux, and oxygen, the requirement is concomitant with an increase in the degree of metallization and post-combustion ratio. The model reported here has been benchmarked using industrial data obtained from the JSW Steel Plant, India.

Processes of high-T fluid-rock interaction during gold mineralization in carbonate-bearing metasediments: the Navachab gold deposit, Namibia

NASA Astrophysics Data System (ADS)

Dziggel, A.; Wulff, K.; Kolb, J.; Meyer, F. M.

2009-08-01

The Navachab gold deposit in the Damara belt of central Namibia is hosted by a near-vertical sequence of amphibolite facies shelf-type metasediments, including marble, calc-silicate rock, and biotite schist. Petrologic and geochemical data were collected in the ore, alteration halos, and the wall rock to evaluate transport of elements and interaction between the wall rock and the mineralizing fluid. The semi-massive sulfide lenses and quartz-sulfide veins are characterized by a complex polymetallic ore assemblage, comprising pyrrhotite, chalcopyrite, sphalerite, and arsenopyrite, native bismuth, gold, bismuthinite, and bismuth tellurides. Mass balance calculations indicate the addition of up to several orders of magnitude of Au, Bi, As, Ag, and Cu. The mineralized zones also record up to eightfold higher Mn and Fe concentrations. The semi-massive sulfide lenses are situated in the banded calc-silicate rock. Petrologic and textural data indicate that they represent hydraulic breccias that contain up to 50 vol.% ore minerals, and that are dominated by a high-temperature (T) alteration assemblage of garnet-clinopyroxene-K-feldspar-quartz. The quartz-sulfide veins crosscut all lithological units. Their thickness and mineralogy is strongly controlled by the composition and rheological behavior of the wall rocks. In the biotite schist and calc-silicate rock, they are up to several decimeters thick and quartz-rich, whereas in the marble, the same veins are only a few millimeters thick and dominated by sulfides. The associated alteration halos comprise (1) an actinolite-quartz alteration in the biotite schist, (2) a garnet-clinopyroxene-K-feldspar-quartz alteration in the marble and calc-silicate rock, and (3) a garnet-biotite alteration that is recorded in all rock types except the marble. The hydrothermal overprint was associated with large-scale carbonate dissolution and a dramatic increase in CO2 in the ore fluid. Decarbonation of wall rocks, as well as a low REE content of the ore fluid resulted in the mobilization of the REE, and the decoupling of the LREE from the HREE. The alteration halos not only parallel the mineralized zones, but may also follow up single layers away from the mineralization. Alteration is far more pronounced facing upward, indicating that the rocks were steep when veining occurred. The petrologic and geochemical data indicate that the actinolite-quartz- and garnet-clinopyroxene-K-feldspar-quartz alterations formed in equilibrium with a fluid (super-) saturated in Si, and were mainly controlled by the composition of the wall rocks. In contrast, the garnet-biotite alteration formed by interaction with a fluid undersaturated in Si, and was mainly controlled by the fluid composition. This points to major differences in fluid-rock ratios and changes in fluid composition during alteration. The alteration systematics and geometry of the hydrothermal vein system are consistent with cyclic fluctuations in fluid pressure during fault valve action.

Disseminated gold-sulfide mineralization at the Zhaima deposit, eastern Kazakhstan

NASA Astrophysics Data System (ADS)

Kovalev, K. R.; Kuzmina, O. N.; Dyachkov, B. A.; Vladimirov, A. G.; Kalinin, Yu. A.; Naumov, E. A.; Kirillov, M. V.; Annikova, I. Yu.

2016-03-01

The Zhaima gold-sulfide deposit is located in the northwestern part of the West Kalba gold belt in eastern Kazakhstan. The mineralization is hosted in Lower Carboniferous volcanic and carbonate rocks formed under conditions of marginal-sea and island-arc volcanic activity. The paper considers the mineralogy and geochemistry of primary gold-sulfide ore and Au-bearing weathering crusts. Au-bearing arsenopyrite-pyrite mineralization formed during only one productive stage. Disseminated, stringer-disseminated, and massive rocks are enriched in Ti, Cr, V, Cu, and Ni, which correspond to the mafic profile of basement. The main ores minerals are represented by finely acicular arsenopyrite containing Au (up to few tens of ppm) and cubic and pentagonal dodecahedral pyrite with sporadic submicroscopic inclusions of native gold. The sulfur isotopic composition of sulfides is close to that of the meteoritic standard (δ34S =-0.2 to +0.2). The 40Ar/39Ar age of three sericite samples from ore veinlets corresponds to the Early Permian: 279 ± 3.3, 275.6 ± 2.9, and 272.2 ± 2.9 Ma. The mantle source of sulfur, ore geochemistry, and spatial compatibility of mineralization with basic dikes allow us to speak about the existence of deep fluid-magmatic systems apparently conjugate with the Tarim plume.

Effect of Tourmaline-Doped on the Far Infrared Emission of Iron Ore Tailings Ceramics.

PubMed

Liu, Jie; Meng, Junping; Liang, Jinsheng; Zhang, Hongchen; Gu, Xiaoyang

2016-04-01

Iron ore tailings as secondary resources have been of great importance to many countries in the world. Their compositions are similar to that of infrared emission ceramics, but there are few reports about it. In addition, tourmaline has high infrared emission properties due to its unique structure. With the purpose of expanding functional utilization of iron ore tailings, as well as reducing the production cost of far infrared ceramics, a new kind of far infrared emission ceramics was prepared by using iron ore tailings, calcium carbonate, silica, and natural tourmaline. The ceramics powders were characterized by Fourier transform infrared spectroscope, X-ray diffraction and scanning electron microscopy, respectively. The results show that after being sintered at 1065 °C, the percentage of pseudobrookite and lattice strain of samples increased with increasing the elbaite content. Furthermore, the added tourmaline was conducive to the densification sintering of ceramics. The appearance of Li-O vibration at 734.73 cm-1, as well as the strengthened Fe-O vibration at 987.68 cm-1 were attributed to the formation of Li0.375Fe1.23Ti1.4O5 solid solution, which led the average far infrared emissivity of ceramics increase from 0.861 to 0.906 within 8-14 µm.

In-situ Pb isotope analysis of Fe-Ni-Cu sulphides by laser ablation multi-collector ICPMS: New insights into ore formation in the Sudbury impact melt sheet

NASA Astrophysics Data System (ADS)

Darling, J. R.; Storey, C. D.; Hawkesworth, C. J.; Lightfoot, P. C.

2012-12-01

Laser-ablation (LA) multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) is ideally suited to in situ determination of isotope ratios in sulphide minerals. Using samples of magmatic sulphide ore from the Sudbury impact structure, we test LA-MC-ICPMS analytical protocols that aim to meet a range of analytical challenges in the analysis of Pb isotopes. These include: potential matrix sensitive isotopic fractionation; interferences on Pb isotopes; low melting points of many sulphide minerals; the availability of standards. Magmatic sulphides of wide ranging mineralogy (pyrrhotite, pentlandite, chalcopyrite, pyrite and sphalerite) were analysed for Pb isotopic composition, using the silicate glass NIST SRM 610 as an external standard to correct for instrumental mass-fractionation. Despite matrix sensitive melting and re-deposition around ablation pits, several lines of evidence indicate that all analyses are accurate, within typical analytical uncertainties of 0.003-2% (2σ), and that the defined approach is insensitive to compositional diversity in sample matrix: (a) laser ablation and dissolution based measurements of sulphide powders are in agreement; (b) analyses from each sample define isochron ages within uncertainty of the known crystallization age (1850 Ma); (c) the results of sulphide measurements by laser ablation are consistent with age-corrected feldspar analyses from the same samples. The results have important implications for ore formation in Sudbury. The Pb isotope data regressions are consistent with age corrected feldspar analyses from each respective sample, which together with time integrated Th/U ratios that match whole rock values (3.1, 4.0 and 6.1 for the Worthington, Copper Cliff and Parkin Offset Dykes, respectively) indicate chemical equilibrium between the silicate and sulphide systems during ore formation. The sulphides within each respective sample have indistinguishable model initial Pb isotope ratios (207Pb/204Pbm), irrespective of mineralogy or texture, indicating a common origin for ores within each of three different Offset Dykes. Furthermore, variations between Offset Dykes (e.g., 207Pb/204Pbm = 15.514 ± 0.012, 15.399 ± 0.009 and 15.275 ± 0.003) show that the ores have differing crustal sources on previously unrecognized scales. Mass balance considerations, particularly for MgO, Ni and Cu, indicate that the spatial distribution of mafic target rocks played a significant role in controlling the mineralization potential in different parts of the melt sheet.

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

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-09-01

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

New understanding on separation of Mn and Fe from ferruginous manganese ores by the magnetic reduction roasting process

NASA Astrophysics Data System (ADS)

Liu, Bingbing; Zhang, Yuanbo; Wang, Juan; Wang, Jia; Su, Zijian; Li, Guanghui; Jiang, Tao

2018-06-01

Magnetic reduction roasting followed by magnetic separation process is reported as a simple route to realize separation of Mn and Fe from ferruginous manganese ores (Fe-Mn ores). However, the separation and recovery of Mn and Fe oxides are not very effective. This work clarified the underlying reason for the poor separation and also proposed some suggestions for the magnetic reduction process. In this work, the effect of temperature on the magnetic reduction roasting - magnetic separation of Fe-Mn ore was investigated firstly. Then the reduction behaviors of MnO2-Fe2O3 system and MnO2-Fe2O3-10 wt.%SiO2 system under 10 vol.% CO-90 vol.% CO2 at 600-1000 °C were investigated by XRD, XPS, SEM-EDS, VSM, DSC and thermodynamics analyses. Reduction and separation tests showed that higher reduction temperature was beneficial to the recovery of iron while it's not in favor of the recovery of manganese when the temperature was over 800 °C. The formation of composite oxide MnxFe3-xO4 with strong magnetism between the interface of the MnO2 and Fe2O3 particles leaded to the poor separation of iron and manganese. In addition, the formation mechanism of MnxFe3-xO4 from MnO2 and Fe2O3 as well as the interface reaction reduced under 10 vol.% CO was discussed in this study. Finally, some suggestions were recommended for the magnetic reduction roasting for utilizing the Fe-Mn ores effectively.

Uniformity in sulfur isotope composition in the orogenic gold deposits from the Dharwar Craton, southern India

NASA Astrophysics Data System (ADS)

Sakthi Saravanan, C.; Mishra, B.

2009-07-01

The sulfur isotope composition of sulfides (mainly pyrite and arsenopyrite) from gold deposits/prospects of the Dharwar Craton such as Hutti, Hira-Buddini, Uti, Kolar (Chigargunta), Ajjanahalli, and Jonnagiri has a narrow range (δ34S = +1.1 to +7.1‰). Such craton-scale uniformity of the above gold camps is noteworthy, in spite of the wide diversity in host rock compositions and their metamorphic conditions, and suggests a magmatic or average crustal source of sulfur for all deposits studied. In addition, our study points towards gold precipitation from reduced ore fluids, with near-homogeneous sulfur isotope compositions.

Manganese Deposits in the Artillery Mountains Region, Mohave County, Arizona

USGS Publications Warehouse

Lasky, S.G.; Webber, B.N.

1944-01-01

The manganese deposits of the Artillery Mountains region lie within an area of about 25 square miles between the Artillery and Rawhide Mountains, on the west side of the Bill Williams River in west-central Arizona. The richest croppings are on the northeast side of this area, among the foothills of the Artillery Mountains. They are 6 to 10 miles from Alamo. The nearest shipping points are Congress, about 50 miles to the east, and Aguila, about 50 miles to the southeast. The principal manganese deposits are part of a sequence of alluvial fan and playa material, probably of early Pliocene age, which were laid down in a fault basin. They are overlain by later Pliocene (?) basalt flows and sediments and by Quaternary basalt and alluvium. The Pliocene (?) rocks are folded into a shallow composite S1ncline ttat occupies the valley between the Artillery and Rawhide Mountains, and the folded rocks along either side of the valley, together with the overlying Quaternary basalt, are broken by faults that have produced a group of horsts, grabens, and step-fault blocks. The manganiferous beds, lie at two zones, 750 to 1,000 feet apart stratigraphically, each of which is locally as much as 300 to 400 feet thick. The main, or upper, zone contains three kinds of ore - sandstone ore, clay ore, and 'hard' ore. The sandstone and clay ores differ from the associated barren sandstone and clay, with which they are interlayered and into which they grade, primarily in containing a variable proportion of amorphous manganese oxides, besides iron oxides and clayey material such as are present in the barren beds. The 'hard' ore is sandstone that has been impregnated with opal and calcite and in which the original amorphous manganese oxides have been largely converted to psilomelane and manganite. The average manganese content of the sandstone and clay ores is between 3 and 4 percent and that of the 'hard' ore is between 6 and 7 percent. The ore contains an average of 3 percent of iron, 0.08 percent of phosphorus, 1.1 percent of barium, and minute quantities of copper, lead, and zinc. Although the manganese content of the sandstone and clay ore may change abruptly from bed to bed, the content within any individual bed changes gradually, and for any large volume of ore both the nanganese and iron content are remarkably uniform. Explorations to June 1941 consisted chiefly of 49 holes diamond-drilled in the upper zone on the Artillery Mountains side of the area. The district is estimated to contain an assured minimum of 200,000,000 tons of material having an average manganese content of 3 to 4 percent. About 20,000,000 tons of this total contains 5 percent or more of manganese, and 2,000,000 to 3,000,000 tons contains 10 percent or more. To what extent these deposits can be utilized is a metallurgical and economic problem. Although the clay and sandstone ores, as well as the 'hard' ore, are present in large tonnages, the 'hard' ore is the only kind that combines minable tonnage with promising grade. About 15,000,000 tons of 'hard' ore is present; about 500,000 tons of this contains 15 percent or more of manganese and averages 17 percent, and somewhat over 2,000,000 tons contains 10 percent or more and averages nearly 13 percent. Except for closer drilling to determine such things as the tonnage, grade, spacing, and form of the richer shoots with greater accuracy before beginning to mine them, further explorations are not recommended, for any new ore found is likely to be similar, both in grade and kind, to that already discovered.

Volatile behavior and trace metal transport in the magmatic-geothermal system at Pūtauaki (Mt. Edgecumbe), New Zealand

NASA Astrophysics Data System (ADS)

Norling, B.; Rowe, M. C.; Chambefort, I.; Tepley, F. J.; Morrow, S.

2016-05-01

The present-day hydrothermal system beneath the Kawerau Geothermal Field, in the Taupo Volcanic Zone, New Zealand, is likely heated from the Pūtauaki (Mt. Edgecumbe) magma system. The aim of this work, as an analog for present day processes, is to identify whether or not earlier erupted Pūtauaki magmas show evidence for volatile exsolution. This may have led to the transfer of volatile components from the magmatic to hydrothermal systems. To accomplish this, minerals and melt inclusions from volcanic products were analyzed for abundances of volatile and ore-forming elements (S, Cl, Li, Cu, Sn, Mo, W, Sb, As, and Tl). The variations in abundance of these elements were used to assess magma evolution and volatile exsolution or fluxing in the magma system. Melt inclusions suggest the evolution of Pūtauaki andesite-dacite magmas is predominantly driven by crystallization processes resulting in rhyodacite-rhyolite glass compositions (although textural and geochemical evidence still indicate a role for magma mixing). Measured mineral-melt partition coefficients for trace metals of interest indicates that, with the exception of Tl in biotite, analyzed metals are all incompatible in Pūtauaki crystallization products. Excluding Li and Cu, other volatile and ore metals recorded in melt inclusions behave incompatibly, with concentrations increasing during evolution from rhyodacitic to rhyolitic melt compositions. Li and Cu appear to have increased mobility likely resulting from diffusive exchange post-crystallization, and may be related to late volatile fluxing. Although S and Cl concentrations decrease with melt evolution, no mineralogical evidence exists to indicate the exsolution and mobility of ore-forming metals from the magma at the time of crystallization. This observation cannot rule out the potential for post-crystallization volatile exsolution and ore-forming metal mobilization, which may only be recorded as diffusive re-equilibration of more rapidly diffusing elements (e.g., Li and Cu).

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.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

High salinity volatile phases in magmatic Ni-Cu-platinum group element deposits

NASA Astrophysics Data System (ADS)

Hanley, J. J.; Mungall, J. E.

2004-12-01

The role of "deuteric" fluids (exsolved magmatic volatile phases) in the development of Ni-Cu-PGE (platinum group element) deposits in mafic-ultramafic igneous systems is poorly understood. Although considerable field evidence demonstrates unambiguously that fluids modified most large primary Ni-Cu-PGE concentrations, models which hypothesize that fluids alone were largely responsible for the economic concentration of the base and precious metals are not widely accepted. Determination of the trace element composition of magmatic volatile phases in such ore-forming systems can offer considerable insight into the origin of potentially mineralizing fluids in such igneous environments. Laser ablation ICP-MS microanalysis allows researchers to confirm the original metal budget of magmatic volatile phases and quantify the behavior of trace ore metals in the fluid phase in the absence of well-constrained theoretical or experimental predictions of ore metal solubility. In this study, we present new evidence from major deposits (Sudbury, Ontario, Canada; Stillwater Complex, Montana, U.S.A.) that compositionally distinct magmatic brines and halide melt phases were exsolved from crystallizing residual silicate melt and trapped within high-T fluid conduits now comprised of evolved rock compositions (albite-quartz graphic granite, orthoclase-quartz granophyre). Petrographic evidence demonstrates that brines and halide melts coexisted with immiscible carbonic phases at the time of entrapment (light aliphatic hydrocarbons, CO2). Brine and halide melt inclusions are rich in Na, Fe, Mn, K, Pb, Zn, Ba, Sr, Al and Cl, and homogenize by either halite dissolution at high T ( ˜450-700° C) or by melting of the salt phase (700-800° C). LA-ICPMS analyses of single inclusions demonstrate that high salinity volatile phases contained abundant base metals (Cu, Fe, Sn, Bi) and precious metals (Pt, Pd, Au, Ag) at the time of entrapment. Notably, precious metal concentrations in the inclusions are comparable to and often exceed the economic concentrations of the metals within the ores themselves. As a consequence of these results, current genetic models must be revised to consider the role played by hydrous saline melts and magmatic brines in deposit development, and the potential for interaction and competition between sulfide liquids (or PGE-bearing sulfide minerals) and hydrosaline volatiles for available PGE and Au in a crystallizing mafic igneous system must be critically evaluated.

A highly oxidized atmosphere-ocean system and oceanic molybdenum drawdown during the Paleoproterozoic

NASA Astrophysics Data System (ADS)

Goto, K. T.; Ito, T.; Suzuki, K.; Anbar, A. D.; Gordon, G. W.; Kashiwabara, T.; Takaya, Y.; Shimoda, G.; Nozaki, T.; Kiyokawa, S.; Tetteh, G. M.; Nyame, F. K.

2014-12-01

Multiple lines of evidence suggest that the first major oxidation of the atmosphere-ocean system occurred during the Paleoproterozoic. However, the course of this redox transition remains elusive. A number of large Mn deposits are distributed in Paleoproterozoic sedimentary successions. As Mn is a redox-sensitive element characterized by high redox potential, knowledge of the Mn cycle in Paleoproterozoic seawater may provide insight into redox evolution during this period. Here, we investigate the Mn cycle in Paleoproterozoic seawater based on the Re-Os and Mo isotope compositions, and the abundance of major and trace elements, in Mn-rich sedimentary rocks from the Nsuta deposit of the Birimian Supergroup, Ghana. The Mn ore is composed mainly of rhodochrosite and is distributed at the boundaries between sedimentary rocks and tholeiitic volcanic rocks. The Re-Os isochron age (2217 ± 100 Ma) we obtained was consistent with U-Pb zircon ages of the volcanic rocks. The manganophile elements, except for Mo, show no enrichment, which is similar to modern hydrothermal Mn oxides. The PAAS-normalized REE compositions show positive Ce anomaly, indicative of Ce enrichment due to the oxidation of Ce(III) by Mn(IV). These findings suggest that Mn ore formed from primary precipitation of Mn oxides from hydrothermal fluids as they were mixed with bottom seawater at ~2.2 Ga. Thus, the bottom seawater would have been sufficiently oxygenated for the precipitation of Mn oxides at ~2.2 Ga. The Nsuta ore samples exhibit slight Mo enrichment, but Mo/Mn ratios are orders of magnitude lower than those in modern hydrothermal Mn oxides. We also found that the Mo isotopes in the Nsuta ore are ~0.7‰ heavier than those in modern hydrothermal and hydrogenous Mn oxides. As Mo in hydrothermal Mn oxides is sourced primarily from seawater (Goto et al., in prep), these results may reflect smaller oceanic Mo inventory and heavier seawater Mo isotope composition at 2.2 Ga than those of present-day. Our calculation using a simple mass balance model suggests that substantial removal of light Mo by Mn oxides may have caused such oceanic conditions. Our findings are consistent with the recently proposed 'oxygen overshoot' model (Bekker and Holland, 2012) and low Mo contents in ~2.2-Ga black shales and sedimentary pyrites (e.g., Scott et al., 2008).

The preliminary result of the δ65Cu and δ34S values of major ore minerals in the Erdenetiin-Ovoo Cu-Mo porphyry deposit, Northern Mongolia

NASA Astrophysics Data System (ADS)

KIM, Y.; Lee, I.; Oyungerel, S.; Jargal, L.; Tsedenbal, T.; Ryu, J. S.

2016-12-01

The copper isotope (δ65Cu) and sulfur isotope (δ34S) compositions of major ore minerals from the Erdenetiin-Ovoo Cu-Mo porphyry deposit were measured to trace sources of copper and sulfur, and to evaluate the precipitation environment of ore minerals. The major ore minerals are pyrite, chalcopyrite, molybdenite and chalcocite developed in the QSP (Quartz-Sericite-Pyrite) alteration zone. The sulfide minerals such as sphalerite and covellite, and carbonate ore minerals like malachite, azurite are also identified. The copper isotope ratios (65Cu/63Cu) of copper ore minerals (chalcopyrite, chalcocite, malachite, azurite, covellite and chrysocolla) were analyzed by the MC-ICPMS in KBSI located in Ochang, South Korea. The measured δ65Cu values relative to NIST 976 range from -1.01 ‰ to 5.76 ‰. The average δ65Cu values of sulfide minerals such as chalcopyrite (1.03 ‰), chalcocite (0.62 ‰) and covellite (0.51 ‰) seem to be relatively lower than those of carbonate and silicate Cu minerals such as malachite (0.24 ‰), azurite (2.17 ‰) and chrysocolla (5.76 ‰). The sulfur isotope ratios (34S/32S) of major sulfide minerals were measured by EA-CF-IRMS (Elemental Analyzer - Continuous Flow - Isotope Ratio Mass Spectrometer) in NCIRF, Seoul National University. The average δ34SV-CDT value is -1.1 ‰ indicating the magmatic signature of sulfur. There is the difference of δ34S values between sulfide minerals. While the δ34S values of pyrite, chalcopyrite and molybdenite range from -0.9 to 0.8 ‰, the δ34S values of chalcocite range from -2.6 ‰ to -1.4 ‰. These lower values might be attributed to the sulfur isotope fractionation during its precipitation.

Characterization and timing of the different types of fluids present in the barren and ore-veins of the W-Sn deposit of Panasqueira, Central Portugal

NASA Astrophysics Data System (ADS)

Noronha, F.; Doria, A.; Dubessy, J.; Charoy, B.

1992-01-01

The Panasqueira W-Sn deposit is the largest quartz-vein type deposit of the Iberian Peninsula and the most important wolframite deposit in Western Europe. The ore-veins are almost exclusively sub-horizontal. Besides ore-bearing sub-horizontal veins, the Panasqueira mine also contains barren quartz veins. There are essentially two generations of barren quartz: quartz, contemporaneous with the earliest regional metamorphism (QI), and recrystallized quartz, contemporaneous with the thermal metamorphism related to the granite intrusion (QII). Fluid inclusion studies (microthermometry and Raman) were undertaken in order to distinguish fluids contemporaneous with the barren quartz from those contemporaneous with the ore-bearing quartz (QIII). Fluid inclusion data indicate that the barren and ore-bearing quartz fluids are dominantly aqueous (93 to 98 mol% H2O), with a nearly constant bulk salinity (8 to 12 wt% eq. NaCl), with the quantity of volatile component (determined by Raman spectrometry) higher in QIII, but never greater than 5 mol%. However, the CO2/CH4 + N2 ratio is different for each type of quartz. Volatiles are dominated by CH4 (10 to 96 mol% ZCH4 and/or N2 (3 to 87 mol% ZN2) in the barren quartz and by CO2 (60 to 73 mol% ZCO2) in ore-bearing quartz. The bulk chemical composition of the fluids in QIII is comparable to that found commonly in hydrothermal fluids associated with wolframite mineralization, where Na>K>Ca and HCO3>Cl>SO4. A dispersion in TH (226 to 350 °C) found in QIII, together with a variation in the degree of filling (0.5 to 0.7) and with the consequent variation of fluid densities (0.70 to 0.79), may result from changes in the fluid pressure regime below lithostatic pressure, suggesting vein filling related to tectonic events.

Two mineralization events in the Baiyinnuoer Zn-Pb deposit in Inner Mongolia, China: Evidence from field observations, S-Pb isotopic compositions and U-Pb zircon ages

NASA Astrophysics Data System (ADS)

Jiang, Si-Hong; Chen, Chun-Liang; Bagas, Leon; Liu, Yuan; Han, Ning; Kang, Huan; Wang, Ze-Hai

2017-08-01

The Xing-Mong Orogenic Belt (XMOB) is located in the eastern part of the Central Asian Orogenic Belt (CAOB) and has experienced multiple tectonic events. The Baiyinnuoer Pb-Zn deposit may be a rare case that documents two periods of mineralization in the tectonically complex XMOB. There are two types of Pb-Zn mineralization in the deposit: (1) skarn-type ore, hosted by the skarn in the contact zone between marble and granodiorite and within the marble and (2) vein-type ore, hosted by crystal tuff and feldspar porphyry. This study revealed that the host rocks, mineral assemblages, mineralization occurrences, S-Pb isotopes, and ages between the two types of ore are notably different. Zircon U-Pb dating indicates that the granodiorite was emplaced in the Early Triassic (244 ± 1 to 242 ± 1 Ma), the crystal tuff was deposited in the Early Cretaceous (140 ± 1 to 136 ± 1 Ma), and the feldspar porphyry was intruded in the Early Cretaceous (138 ± 2 to 136 ± 2 Ma). The first skarn mineralization occurred at ∼240 Ma and the second vein-type Pb-Zn mineralization took place between 136 and 129 Ma. Thus the Triassic orebodies were overprinted by Early Cretaceous mineralization. The sphalerite and galena from the skarn mineralization have higher δ34S values (-4.7 to +0.3‰) than the sphalerite, galena and aresenopyrite from the vein-type mineralization (-7.5 to -4.2‰), indicating different sulfur sources or ore-forming processes for the two types of mineralization. The Pb isotopic compositions of the two types of ore are very similar, suggesting similar lead sources. Geochemistry and Nd-Pb-Hf isotopic systematics of the igneous rocks in the region show that the Triassic granodiorite was generated from hybridization of mafic and felsic magmas due to strong crust-mantle interaction under the collisional setting that resulted following the closure of the Paleo-Asian Ocean and the collision of North China and Siberian cratons at the end of the Permian; while the Cretaceous igneous rocks at Baiyinnuoer originated from the partial melting of a juvenile lower crust with minor input from the crust caused by the underplating of mafic magma in an extensional setting.

Platinum potential of mafic-ultramafic massifs in the western part of the Dambuka ore district (Upper Amur Region, Russia)

NASA Astrophysics Data System (ADS)

Melnikov, A. V.; Stepanov, V. A.; Moiseenko, V. G.

2016-02-01

New data on the Pt potential of mafic-ultramafic massifs of the Khani-Maya, Uldegit, and Dzhalta complexes in the western part of the Dambuka ore district are discussed. The Khani-Maya Complex is represented by metamorphosed gabbro, gabbronorites, gabbro anorthosites, subordinate pyroxenites, hornblendites, and peridotites. The Uldegit Complex is composed of pyroxenites, hornblendites, gabbro, gabbronorites, norites, troctolites, peridotites, dunites, actinolite-tremolites, serpentinites, anthophyllites, and tremolite-plagioclase rocks. The Dzhalta Complex is formed of peridotites, gabbro, eclogitized gabbro, hornblendites, cortlandites, and pyroxenites. All these complexes differ from each other by the concentrations of Ni, Cu, Co, Au, and platinoids depending on the composition of the constituting rocks and the presence of sulfide minerals.

Behaviour of the pH Adjustment, Ion Exchange and Concentrate Precipitation Stages in the Acid Leaching of Uranium Phosphate Ores; TRATAMIENTO DE DISOLUCIONES DE LIXIVIACION DE MINERALES DE URANIO EN PRESENCIA DE FOSFATOS. COMPORTAMIENTO EN LAS ETAPAS DE AJUSTE DE PH, CAMBIO DE ION Y PRECIPITACION DE CONCENTRADOS (in Spanish)

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

Aguilar, J.E.; Hueda, A.U.

Recovery of U from acid leach solutions of phosphate ore was studied. It was found that predictions can be made concerning solids removal and U recovery in the pH adjustment stage, resin U capacity, eluating agent suitability, ion exchange stage eluation velocity and eluate U concentration, and composition of the precipitate formed in the concentration stage. The results are valid in the concentration range 0.3 to 0. 8 g U/sub 3/O/sub 8//1. (J.R.D.)

Transformation and contamination of soils in iron ore mining areas (a review)

NASA Astrophysics Data System (ADS)

Zamotaev, I. V.; Ivanov, I. V.; Mikheev, P. V.; Belobrov, V. P.

2017-03-01

Current concepts of soil transformation and contamination in iron ore mining areas have been reviewed. Changes of soils and ecosystems in the mining areas are among the largest-scale impacts of economic activity on the nature. Regularities in the radial differentiation, spatial distribution, and accumulation of heavy metals in soils of different natural zones are analyzed. The effects of mining technogenesis and gas-dust emissions from enterprises on soil microbial communities and fauna are considered. In zones of longterm atmotechnogenic impact of mining and processing plants, the stable state of ecosystems is lost and/or a new technoecosystem different from the natural one, with own microbial cenosis, is formed, where communities of soil organisms are in the stress state. In the ore mining regions, embriozems are formed, which pass through specific stages of technogenically-determined development, as well as technosols, chemozems, and technogenic surface formations with variable material compositions and properties. Technogenic soils and soil-like bodies form a soil cover differing from the initial one, whose complexity and contrast are not related to the natural factors of differentiation.

Rhenium in ores of the Mikheevskoe porphyry Cu-Mo deposit, South Urals

NASA Astrophysics Data System (ADS)

Plotinskaya, O. Yu.; Grabezhev, A. I.; Seltmann, R.

2015-03-01

The distribution of Re in ores of the Mikheevskoe Mo-Cu deposit in the South Urals is studied. It is established that the grade of Re in the ores usually does not exceed 0.5 g/t. A positive correlation between concentrations of Re and Mo (correlation coefficient 0.94), and Re and Cu (correlation coefficient 0.52) is found. EMPA of individual flakes of molybdenite showed that a Re content higher than the detection limit has been measured in most flakes studied, as a rule as high as 0.4-0.5 wt %, but occasionally reaching 1.34 wt %. Re within flakes of molybdenite is irregularly distributed. Patchy, linear, and concentric-zoned patterns of zones with elevated Re content (usually 0.5-1 wt % Re, sometimes higher) are found against the lower content (up to 0.2 wt % Re) that is regularly distributed within the flake. Later hydrothermal processes and mechanical deformation of flakes result in epigenetic Re redistribution in molybdenite that leads to homogenization of molybdenite composition and smoothing of primary pattern, or removal of Re from molybdenite.

Sedimentary carbonate-hosted giant Bayan Obo REE-Fe-Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin

USGS Publications Warehouse

Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Tatsumoto, M.; Junwen, Wang; Conrad, J.E.; McKee, E.H.; Zonglin, Hou; Qingrun, Meng; Shengguang, Huang

1997-01-01

Detailed, integrative field and laboratory studies of the textures, structures, chemical characteristics, and isotopically determined ages and signatures of mineralization of the Bayan Obo deposit provided evidence for the origin and characteristics favorable for its formation and parameters necessary for defining giant polymetallic deposits of hydrothermal origin. Bayan Obo is an epigenetic, metasomatic, hydrothermal rare earth element (REE)-Fe-Nb ore deposit that is hosted in the metasedimentary H8 dolostone marble of the Middle Proterozoic Bayan Obo Group. The metasedimentary sequence was deposited on the northern continental slope of the North China craton. The mine area is about 100 km south of the suture marking Caledonian subduction of the Mongolian oceanic plate from the north beneath the North China craton. The mineralogy of the deposit is very complex, consisting of more than 120 different minerals, some of which are epigenetic minerals introduced by hydrothermal solutions, and some of which are primary and secondary metamorphic minerals. The major REE minerals are monazite and bastnaesite, whereas magnetite and hematite are the dominant Fe-ore minerals, and columbite is the most abundant Nb mineral. Dolomite, alkali amphibole, fluorite, barite, aegirine augite, apatite, phlogopite, albite, and microcline are the most widespread gangue minerals. Three general types of ores occur at Bayan Obo: disseminated, banded, and massive ores. Broad zoning of these ore types occurs in the Main and East Orebodies. Disseminated ores are in the outermost zone, banded ores are in the intermediate zone, and massive ores are in the cores of the orebodies. On the basis of field relations, host rocks, textures, structures, and mineral assemblages, many varieties of these three types of ores have been recognized and mapped. Isotopic dating of monazite, bastnaesite, aeschynite, and metamorphic and metasomatic alkali amphiboles associated with the deposit provides constraints on the ages of mineralization and the history of the deposit. Textural relations, differences in chemical composition, and 232Th/208Pb internal isochron ages of monazite and bastnaesite samples indicate that many episodes of REE mineralization occurred at Bayan Obo, ranging from about 555 Ma to about 398 Ma. Initial 208Pb/204Pb ratios suggest different sources of REE's for different generations of REE minerals. Relative ages of Fe mineralization were deduced from textural relationships of Fe minerals with other, dated mineral phases in the deposit. Most Nb mineralization was in the area of the West Orebodies and resulted in disseminated ore. Aeschynite, an early stage of Nb mineralization (438+-25.1 Ma), occurs with huanghoite and alkali amphiboles in veins. The 40Ar/39Ar ages of amphiboles, as well as petrographic textures, were used to distinguish three periods of regional metamorphism in the Bayan Obo mine area: (1) Late Proterozoic, about 890 Ma, which recrystallized H8 carbonate to marble and crystallized lineated alkali amphiboles along foliation planes in the marble; (2) Caledonian, about 425-395 Ma, which resulted in metamorphic and metasomatic-metamorphic alkali amphiboles; and (3) Hercynian, about 300 Ma, based on biotite 40Ar/39Ar analyses from biotite schist and folded banded ores. The 40Ar/39Ar ages of metasomatic alkali amphiboles also place time constraints on the hydrothermal history of the ore deposit. Metasomatic amphiboles represent periods of intense hydrothermal activity, which began as early as 1.26 Ga; that date is based on the age of amphibole from a vein that crosscuts the H6 quartzite that underlies the H8 dolostone marble. Although much of the metasomatic amphibole formed during periods that overlapped the peak period of REE mineralization of banded ores, REE and alkali amphibole phases generally occur in different mineral assemblages or are of very different ages in the same assemblage and, therefore, may have been derived from

Compositional variation of glauconites in Upper Cretaceous-Paleogene sedimentary iron-ore deposits in South-eastern Western Siberia

NASA Astrophysics Data System (ADS)

Rudmin, Maxim; Banerjee, Santanu; Mazurov, Aleksey

2017-06-01

Glauconite occurs either as unaltered greenish or as altered brownish variety in Upper Cretaceous-Palaeocene sediments in the southeastern corner of Western Siberia. Studied section within the Bakchar iron-ore deposit includes Ipatovo, Slavgorod, Gan'kino and Lyulinvor formations, which are represented by sandstones, siltstones, claystones and oolitic ironstones of coastal-marine facies. The origin of unaltered glauconite is explained by the ;verdissement theory;. Transgressions during Lower Coniacian, Santonian and Campanian favored the formation of unaltered glauconites in dysoxic to anoxic conditions. Subaerial exposure of glauconite resulted in leaching of potassium, oxidation of iron and formation of iron hydroxides in Upper Coniacian, Maastrichtian and Palaeocene. Glauconite ultimately converts to leptochlorite and hydrogoethite by this alteration. Abundant microscopic gold inclusions, besides sulphides, sulphates, oxides and silicates characterize this glauconite. Mineral inclusions include precious, rare metals and non-ferrous metals. The concentration of gold in glauconite may be as high as 42.9 ppb. Abundant inclusions of various compositions in glauconites indicate enrichment of marine sediments in precious and non-precious metals. While major element composition of glauconites is affected by subaerial exposure, the broadly similar micro-inclusions in both altered and unaltered varieties are possibly related to the comparatively immobile nature of REE and trace elements.

The first data on breithauptite in chromitite from the northern part of the Voykar-Synya ultramafic massif (Polar Urals)

NASA Astrophysics Data System (ADS)

Shaibekov, R. I.; Gaikovich, M. M.; Isaenko, S. I.; Shevchuk, S. S.

2017-11-01

This work presents the results of studying the mineral composition of chromite ores of the Khoila area. For the first time, nickel antimonide (breithauptite), including an Au-bearing type (with intergrowths and microinclusions of auricuprides) was found in the paragenesis with chromespinelides.

Soil quality changes in response to their pollution by heavy metals, Georgia.

PubMed

Matchavariani, Lia; Kalandadze, Besik; Lagidze, Lamzira; Gokhelashvili, Nino; Sulkhanishvili, Nino; Paichadze, Nino; Dvalashvili, Giorgi

2015-01-01

The present study deals with the composition, migration and accumulation of heavy metals in irrigated soils, plants and partially natural waters; and also, establishing the possible sources of pollution and their impact on environmental situation. The content of toxic elements in the irrigated soils adjacent to ore mining and processing enterprise were studied. Content of toxic elements in the irrigated soils adjacent to ore mining, showed that more than half of territory was seriously polluted by copper and zinc. Some part of the area were considered catastrophically polluted. Expressed technogenesis taking place influenced irrigation. Heavy metals like copper, zinc and manganese negative by effected the properties of soil, thus composition and soil-forming processes taking place in the soil. It was especially well represented in the deterioration of hydro-physical potential of the soil. Irrigation of agricultural land plots by water, polluted with heavy metals changed the pH. Balanced correlation among solid, liquid and gas phases was disrupted. In highly polluted soil, the cementing processes took place that sharply increased the bulk density of the soil, deteriorated the porosity of soil and reduced water permeability critically.

Solidification/stabilization of chromite ore processing residue using alkali-activated composite cementitious materials.

PubMed

Huang, Xiao; Zhuang, RanLiang; Muhammad, Faheem; Yu, Lin; Shiau, YanChyuan; Li, Dongwei

2017-02-01

Chromite Ore Processing Residue (COPR) produced in chromium salt production process causes a great health and environmental risk with Cr(VI) leaching. The solidification/stabilization (S/S) of COPR using alkali-activated blast furnace slag (BFS) and fly ash (FA) based cementitious material was investigated in this study. The optimum percentage of BFS and FA for preparing the alkali-activated BFS-FA binder had been studied. COPR was used to replace the amount of BFS-FA or ordinary Portland cement (OPC) for the preparation of the cementitious materials, respectively. The immobilization effect of the alkali-activated BFS-FA binder on COPR was much better than that of OPC based cementitious material. The potential for reusing the final treatment product as a readily available construction material was evaluated. X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electron microscope with energy dispersive spectrometer (SEM-EDS) analysis indicated that COPR had been effectively immobilized. The solidification mechanism is the combined effect of reduction, ion exchange, precipitation, adsorption and physical fixation in the alkali-activated composite cementitious material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Geological and geochemical studies of the Shujiadian porphyry Cu deposit, Anhui Province, Eastern China: Implications for ore genesis

NASA Astrophysics Data System (ADS)

Wang, Shiwei; Zhou, Taofa; Yuan, Feng; Fan, Yu; White, Noel C.; Lin, Fengjie

2015-05-01

Most porphyry deposits in the world occur in magmatic arc settings and are related to subduction of oceanic plates. A small proportion of porphyry deposits occur in intracontinental settings, however they are still poorly understood. Shujiadian, a newly-discovered porphyry Cu deposit, is located in the Middle-Lower Yangtze River Valley metallogenic belt and belongs to the intracontinental class. The deposit has classic alteration zones defined by a core of potassic alteration and local Ca-silicate alteration, which is overprinted by a feldspar-destructive alteration zone and cut by veins containing epidote and chlorite. Wallrocks of the deposit are unreactive quartz-rich sedimentary rocks. Three main paragenetic stages have been recognized based on petrographic observations; silicate stage, quartz-sulfide stage, and sulfide-carbonate stage. Quartz + pyrite + chalcopyrite ± molybdenite veins, and quartz + chalcopyrite + pyrite veins of the quartz-sulfide stage contribute most of the copper, and chalcopyrite + chlorite ± pyrite ± pyrrhotite ± quartz ± illite veins of the sulfide-carbonate stage also contribute part of the copper; all the mineralized veins are associated with feldspar-destructive alteration. Investigations on the fluid inclusions in Shujiadian indicate that the ore-forming fluids had four evolutionary episodes: immiscibility and overpressure in the silicate stage, boiling in the quartz-sulfide stage and mixing with meteoric water in the sulfide-carbonate stage. Sulfur and strontium isotope studies suggest that ore metals were mainly derived from magmatic-hydrothermal fluids, and combined with our study of fluid inclusions, we infer that decompression, changes in oxygen fugacity and sulfur content were the main factors that caused Cu precipitation. Compared with porphyry deposits in magmatic arc settings, there are some differences in the ore-bearing rock, alteration, and the composition of ore-forming fluids.

Numerical Study of the Reduction Process in an Oxygen Blast Furnace

NASA Astrophysics Data System (ADS)

Zhang, Zongliang; Meng, Jiale; Guo, Lei; Guo, Zhancheng

2016-02-01

Based on computational fluid dynamics, chemical reaction kinetics, principles of transfer in metallurgy, and other principles, a multi-fluid model for a traditional blast furnace was established. The furnace conditions were simulated with this multi-fluid mathematical model, and the model was verified with the comparison of calculation and measurement. Then a multi-fluid model for an oxygen blast furnace in the gasifier-full oxygen blast furnace process was established based on this traditional blast furnace model. With the established multi-fluid model for an oxygen blast furnace, the basic characteristics of iron ore reduction process in the oxygen blast furnace were summarized, including the changing process of the iron ore reduction degree and the compositions of the burden, etc. The study found that compared to the traditional blast furnace, the magnetite reserve zone in the furnace shaft under oxygen blast furnace condition was significantly reduced, which is conducive to the efficient operation of blast furnace. In order to optimize the oxygen blast furnace design and operating parameters, the iron ore reduction process in the oxygen blast furnace was researched under different shaft tuyere positions, different recycling gas temperatures, and different allocation ratios of recycling gas between the hearth tuyere and the shaft tuyere. The results indicate that these three factors all have a substantial impact on the ore reduction process in the oxygen blast furnace. Moderate shaft tuyere position, high recycling gas temperature, and high recycling gas allocation ratio between hearth and shaft could significantly promote the reduction of iron ore, reduce the scope of the magnetite reserve zone, and improve the performance of oxygen blast furnace. Based on the above findings, the recommendations for improvement of the oxygen blast furnace design and operation were proposed.

New observations on the Ni-Co ores of the southern Arburese Variscan district (SW Sardinia, Italy)

NASA Astrophysics Data System (ADS)

Naitza, Stefano; Secchi, Francesco; Oggiano, Giacomo; Cuccuru, Stefano

2015-04-01

Among the European Variscan regions, the Arburese district, located in the Paleozoic basement of SW Sardinia (Italy) is remarkable for its metallogenic complexity, and offers good opportunities to investigate time/space and genetic links between post-collisional Variscan intrusive magmatism and mineral deposits. The district hosts a large variety of mineral deposits and occurrences, which include the Pb-Zn (Cu, Ag) mesothermal veins of the Montevecchio Lode System, one of the largest and richest Variscan hydrothermal ore deposit of Europe, now exhausted. Ore deposits are genetically related to the emplacement of the Late Variscan (304±1 Ma) Arbus Pluton, a granitoid composite intrusion ranging from monzogabbroic to granodioritic and to peraluminous leucogranitic rock-types. After more than a century of geological studies in the area, several metallogenic issues are still unresolved; among them, the occurrence in the southern sectors of little known polymetallic Ni-Co-(Pb-Zn-Cu-Ag-Bi) veins, a kind of mineralization quite unusual for the Sardinian basement. These hydrothermal deposits are hosted by very low-grade metamorphic rocks at short distance from the intrusion, where contact effect generate also hornfels. Spatial, structural and textural characters of the hydrothermal system are coherent and in apparent continuity with those of the Montevecchio Lode System. Ni-Co ores are hosted by a system of parallel, 1-2 m thick high-angle veins that discontinuously follow the southwestern and southern contacts of the Arbus Pluton for about 7 km. They constantly dip SSW, sideways with respect to the pluton contact, and show a prevalence of fracture infilling (banded and brecciated) textures, with alternating quartz and siderite bands, cockades and frequent inclusions of wallrock fragments. Wallrocks are usually silicified, bleached and/or sericitized. Systematic studies of ore textures and parageneses from different veins along the system have been performed by standard ore microscopy and SEM-EDS. Ore minerals associations include Ni-Co (Fe, Sb) arsenides/sulfoarsenides (nickeline, rammelsbergite, skutterudite, safflorite, gersdorffite, breithauptite, lollingite, cobaltite), Pb-Zn-Cu-Ag-Bi sulfides (galena, sphalerite, chalcopyrite, tetrahedrite/freibergite, bismuthinite, proustite/pyrargirite, stephanite), native Bi and native Ag. Ore textures and mineral phases relationships allow to envisage the following paragenetic sequence: 1) deposition of quartz (I) and a Ni monoarsenide (nickeline), and antimonide (breithauptite) followed by 2) Ni-,Ni-Co, Co- and Fe- di-, tri- arsenides and sulfoarsenides (rammelsbergite, skutterudite, safflorite, löllingite, cobaltite), with bismuthinite and native Bi; 3) deposition of abundant siderite, with quartz (II), Pb-Zn-Cu-Ag sulfides and sulfosalts and rare native Ag, followed at last by 4) calcite. This sequence depicts a polyphased evolution with alternating gradual and abrupt changes of the physicochemical parameters of a mesothermal fluid initially characterized by Ni-As-(Sb) contents, subsequently evolved to higher contents of As, Co and Bi, and, finally, enriched in S, allowing Pb, Zn, Cu deposition as sulfides and sulfosalts.Thus, the fine alternating rims of pure nickeline (NiAs) and breithauptite (NiSb) in nickeline individuals, detected by SEM-EDS, may be explained by repeated compositional re-equilibrations due to variable As and Sb contents of the fluids; increases in As, and, moreover, the sudden appearance of siderite and sulfides after brecciations indicate further re-opening of the system, related to hydrothermal fracturing and syn-depositional tectonics.

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 = 45,32-62,17%, MgO = 7,3-12,5%) allow us to estimate the depth of generation of kimberlite magmas more than 170-200 km. Ilmenites show two groups according to MgO, Cr2O3 and TiO2 content. Reconstructions of the mantle sections show also two intervals of pressures divided at 4.5 GPa, the upper part is highly metasomatized This high degree metasomatism is determined for almost all mantle columns. It is suggested that large-scale of uranium-bearing mantle fluids may be associated with the ancient degasation during the subduction which is highly enriched in U component . Analysis of the reasons for the marked association kimberlitic dykes and major industrial uranium deposits in carbonate-sodium metasomatic in the UkrSh led to the conclusion that hydrothermal uranium deposits are confined to the supply mantle fluid systems of mantle fault zones exercising brings sodium carbonate solutions enriched uranium from mantle sources. References: 1. Kalashnik A.A. New prognostic-evaluation criteria in technology prognosis of forming industrial endogenous uranium deposits of the Ukrainian Shield, 2014. Scientific proceedings of UkrSGRI, № 2, p. 27-54 (in Russian) 2. Stepanjuk L.M., Bondarenko S.V., Somka V.O. and other, 2012. Source of uranium and uranium-bearing sodium albitites for example of Dokuchaievskogo field of the Ingulsky megablock of the UkrSh: Abstracts of scientific conference "Theoretical issues and research practice metasomatic rocks and ores" (Kyiv, 14-16 March 2012), IGMOF, p.78-80. (in Ukrainian)

Discriminating fluid source regions in orogenic gold deposits using B-isotopes

NASA Astrophysics Data System (ADS)

Lambert-Smith, James S.; Rocholl, Alexander; Treloar, Peter J.; Lawrence, David M.

2016-12-01

The genesis of orogenic gold deposits is commonly linked to hydrothermal ore fluids derived from metamorphic devolatilization reactions. However, there is considerable debate as to the ultimate source of these fluids and the metals they transport. Tourmaline is a common gangue mineral in orogenic gold deposits. It is stable over a very wide P-T range, demonstrates limited volume diffusion of major and trace elements and is the main host of B in most rock types. We have used texturally resolved B-isotope analysis by secondary ion mass spectrometry (SIMS) to identify multiple fluid sources within a single orogenic gold ore district. The Loulo Mining District in Mali, West Africa hosts several large orogenic gold ore bodies with complex fluid chemistry, associated with widespread pre-ore Na- and multi-stage B-metasomatism. The Gara deposit, as well as several smaller satellites, formed through partial mixing between a dilute aqueous-carbonic fluid and a hypersaline brine. Hydrothermal tourmaline occurs as a pre-ore phase in the matrix of tourmalinite units, which host mineralization in several ore bodies. Clasts of these tourmalinites occur in mineralized breccias. Disseminated hydrothermal and vein hosted tourmaline occur in textural sites which suggest growth during and after ore formation. Tourmalines show a large range in δ11B values from -3.5 to 19.8‰, which record a change in fluid source between paragenetic stages of tourmaline growth. Pre-mineralization tourmaline crystals show heavy δ11B values (8-19.8‰) and high X-site occupancy (Na ± Ca; 0.69-1 apfu) suggesting a marine evaporite source for hydrothermal fluids. Syn-mineralization and replacement phases show lighter δ11B values (-3.5 to 15.1‰) and lower X-site occupancy (0.62-0.88 apfu), suggesting a subsequent influx of more dilute fluids derived from devolatilization of marine carbonates and clastic metasediments. The large, overlapping range in isotopic compositions and a skew toward the opposing population in the δ11B data for both tourmaline groups reflects continual tourmaline growth throughout mineralization, which records the process of fluid mixing. A peak in δ11B values at ∼8‰ largely controlled by tourmalines of syn- to post-ore timing represents a mixture of the two isotopically distinct fluids. This paper demonstrates that B-isotopes in tourmaline can be instrumental in interpreting complex and dynamic hydrothermal systems. The importance of B as an integral constituent of orogenic ore forming fluids and as a gangue phase in orogenic gold deposits makes B-isotope analysis a powerful tool for testing the level of source region variability in these fluids, and by extension, that of metal sources.

Geology, ore facies and sulfur isotopes geochemistry of the Nudeh Besshi-type volcanogenic massive sulfide deposit, southwest Sabzevar basin, Iran

NASA Astrophysics Data System (ADS)

Maghfouri, Sajjad; Rastad, Ebrahim; Mousivand, Fardin; Lin, Ye; Zaw, Khin

2016-08-01

The southwest Sabzevar basin is placed in the southwestern part of a crustal domain known as the Sabzevar zone, at the north of Central Iranian microcontinent. This basin hosts abundant mineral deposits; particularly of the Mn exhalative and Cu-Zn volcanogenic massive sulfide (VMS) types. The evolution of this basin is governed by the Neo-tethys oceanic crust subduction beneath the Central Iranian microcontinent and by the resulting continental arc (Sanandaj-Sirjan) and back-arc (Sabzevar-Naien). This evolution followed two major sequences: (I) Lower Late Cretaceous Volcano-Sedimentary Sequence (LLCVSS), which is indicated by fine-grained siliciclastic sediments, gray basic coarse-grained different pyroclastic rocks and bimodal volcanism. During this stage, tuff-hosted stratiform, exhalative Mn deposits (Nudeh, Benesbourd, Ferizy and Goft), oxide Cu deposits (Garab and Ferizy) and Cu-Zn VMS (Nudeh, Chun and Lala) deposits formed. (II) Upper Late Cretaceous Sedimentary Dominated Sequence (ULCSS), including pelagic limestone, marly tuff, silty limestone and marl with minor andesitic tuff rocks. The economically most important Mn (Zakeri and Cheshmeh-sefid) deposits of Sabzevar zone occur within the marly tuff of this sequence. The Nudeh Cu-Zn volcanogenic massive sulfide (VMS) deposit is situated in the LLCVSS. The host-rock of deposits consists of alkali olivine basalt flow and tuffaceous silty sandstone. Mineralization occurs as stratiform blanket-like and tabular orebodies. Based on ore body structure, mineralogy, and ore fabric, we recognize three different ore facies in the Nudeh deposit: (1) a stringer zone, consisting of a discordant mineralization of sulfides forming a stockwork of sulfide-bearing quartz veins cutting the footwall volcano-sedimentary rocks; (2) a massive ore, consisting of massive replacement pyrite, chalcopyrite, sphalerite and Friedrichite with magnetite; (3) bedded ore, with laminated to disseminated pyrite, and chalcopyrite. Chloritization, silicification, sericitization and epidotization are the main wall-rock alterations; alteration intensity increases towards the stringer zone. The δ34S composition of the sulfides ranges from -1.5‰ to +3.69‰ with a general increase of δ34S ratios of massive ore facies to stockwork zone. The heavier values indicate that some of the sulfur was derived from seawater sulfate that was ultimately thermochemically reduced in deep hydrothermal reaction zones. Sulfur isotopes, along with sedimentological, textural, petrological, mineralogical, and geochemical evidences, suggest that this deposit should be classified as a Besshi-type VMS ore deposit.

A gallery of oil components, their metals and Re-Os signatures

NASA Astrophysics Data System (ADS)

Stein, Holly J.; Hannah, Judith L.

2016-04-01

Most sediment-hosted metallic ore deposits are one degree of freedom from hydrocarbon. That is, sulfide fluid inclusions may contain vestiges of travel in tandem with hydrocarbon-bearing fluids. For metallic ore deposits of stated metamorphic and magmatic origin, the degrees of freedom are several times more or, in some cases, no relationship exists. Still, the fetish for stereotyping and classifying ore types into hardline ore deposit models (or hybrid models when the data are wildly uncooperative) impedes our ability to move toward a better understanding of source rock. Fluids in the deeper earth, fluids in the crust, and the extraterrestrial rain of metals provide the Re-Os template for oil. So, too, this combination ultimately drives the composition of many metallic ore deposits. The world of crude oil and its complex history of maturation, migration, mixing, metal-rich asphaltene precipitation, and subsequent mobility of lighter and metal-poor components, is an untapped resource for students of ore geology. In the same way that Mississippi Valley-type lead and zinc deposits are described as the outcome of two converging and mixing fluids (metal-bearing and sulfur-bearing fluids), asphaltene precipitation can be an outcome of a lighter oil meeting and mixing with a heavier one. In the petroleum industry, this can spell economic disaster if the pore-space becomes clogged with a non-producible heavy oil or solid bitumen. In ore geology, sulfide precipitation on loss of permeability may create a Pb-Zn deposit. Petroleum systems provide a gallery of successive time-integrated Re-Os results. Heavy or biodegraded oils, if intersected by lighter oil or gas, can generate asphaltite or tar mats, and release a reservoir of still lighter oil (or gas). During this process there are opportunities for separation of metal-enriched aqueous fluids that may retain an imprint of their earlier hydrocarbon history, ultimately trapped in fluid inclusions. Salinity, temperature and pH are part of the equation controlling composition of metal-bearing aqueous fluids siphoned from residual hydrocarbons. The Re-Os isotopic behavior of oil components is generally specific to location and may differ within a single oil field, or even within discrete fractions of a single sample of oil [1]. Different fractions in a crude oil, for example maltenes and asphaltenes, can preserve signatures of unique sources. This should not be surprising, since economic geologists have long called upon meeting and mixing of metal-bearing with sulfur-bearing fluids from different sources. A time-integrated geologic history can also be derived from bitumen veins, with the Re-Os age of the metal source cached in these veins. Preservation of early metal and hydrocarbon history, and intact Re-Os systematics preserved in younger-formed systems have enormous potential for the resource industry. Several examples will be presented. [1] Georgiev, S.V., Stein, H.J., Hannah, J.L., Galimberti, R., Nali, M., Yang, G., and Zimmerman, A. (returned post revision, 11 Jan 2016) Re-Os dating of maltenes and asphaltenes within single samples of crude oils: Geochimica et Comochimica Acta. Supported by a consortium of petroleum companies under the CHRONOS project.

Caractérisation géochimique des fluides associés aux minéralisations Pb sbnd Zn de Bou-Dahar (Maroc)

NASA Astrophysics Data System (ADS)

Adil, Samira; Bouabdellah, Mohammed; Grandia, Fidel; Cardellach, Esteve; Canals, Àngel

2004-11-01

The Bou-Dahar Pb sbnd Zn Mississippi Valley deposits located in the eastern part of the High Atlas Range (Morocco) are hosted by a Liassic reefal complex. Fluid inclusion and 'crush-leach' data show that two distinct fluids were involved in the mineralisation deposition: a warmer, more saline fluid (180 °C, >25 wt% NaCl equivalent) and a cooler, less saline fluid (70 °C, 16 wt% equivalent NaCl). Mixing of these two fluids resulted in the precipitation of the ore. The solute composition of the ore-forming brine suggests that the MVT mineralising fluids were probably a mixture of halite-dissolution fluids and evaporated seawater. To cite this article: S. Adil et al., C. R. Geoscience 336 (2004).

Using melt inclusions and fluid inclusions to track ore-metal behavior in magma-hydrothermal systems (Invited)

NASA Astrophysics Data System (ADS)

Lowenstern, J. B.; Audétat, A.

2013-12-01

Melt and fluid inclusions yield important clues to the history of igneous melts and their related hydrothermal ore deposits (1). Under ideal conditions, melt inclusions in volcanic rocks yield data on the actual concentrations of ore metals and volatiles during instantaneous snapshots of crystallization and degassing. Their varying compositions can directly reflect sequestration of ore-metals in fractionating minerals and/or exsolving brines and vapors. Frequently, scientists compare the concentration of volatile elements in melt inclusions with their abundance in devolatilized matrix glass. Though this provides an informative qualitative overview of volatility, it is essentially impossible to use such data to calculate thermodynamically relevant partition coefficients. The resulting partitioning ratio instead represents fractionation over a wide range of pressures, and compositions (for both exsolved fluid and silicate melt). Ideally, workers should identify co-entrapped fluid and glass inclusions to provide more thermodynamically meaningful partitioning ratios for volatile metals and gases (2,3). Unfortunately, the occurrence of fluid inclusions co-entrapped with silicate melt is relatively rare, and studies of synthetic fluid and melt inclusions may be the most practical means of exploring the effect of crystallization and degassing in 'natural' systems. As with melt inclusions, under ideal conditions, fluid inclusions in intrusive rocks represent the compositions of fluids generated within associated magmatic-hydrothermal fluid systems. Multiple generations of cross-cutting fractures may be generated, resulting in trails of secondary and pseudosecondary inclusions in igneous minerals, and primary and secondary inclusions in hydrothermal assemblages. Chemistry of the fluids preserved within different inclusion generations will change markedly due to changes in magmatic temperature and pressure and mixing of diverse external fluids from meteoric and metamorphic sources. For example, ore elements sequestered by magmatic crystallization at high temperature may be liberated and re-transported by fluids upon magma cooling due to breakdown and dissolution of oxides and sulfides at low temperature. Both fluid and melt inclusions can be open to modification between initial formation and ultimate petrographic inspection. In melt inclusions, bubbles separate from glass and variably re-hydrate the glass during cooling. In addition, crystals can form and elements can diffuse between glass and host mineral. These problems are yet more exaggerated in intrusive rocks, but workers are still able to obtain useful information through meticulous inspection, categorization and analysis through diverse techniques. This presentation will review a variety of recent studies that illustrate these concepts and demonstrate how to extract useful information from inclusions from a variety of deposit types. (1) Audétat, A. & Lowenstern, J.B. (in press) Melt Inclusions. In Scott. S. (ed.) Geochemistry of Mineral Resources: Treatise of Geochemistry, 2nd edition. (2) Zajacz Z, et al. (2008) Geochim et Cosmochim.Acta, 72: 2169-2197. (3) Lerchbaumer, L. & Audétat, A., (2013) Econ. Geol. v. 108, p. 987-1013.

The role of impurity ions in the formation of phase composition of Norilsk ore types

NASA Astrophysics Data System (ADS)

Mashukov, Anatoly; Mashukova, Alla

2013-04-01

Using the methods of X-ray and Mössbauer spectroscopy, scanning electron microscopy, there were studied the samples of Norilsk ore types in order to identify compounds containing Cu and Ni. Depending on elemental composition there were singled out two sample series. Maximum concentration in percentage of selected elements for this series is presented below. 1: Ni (0), Cu (0,42), S (11,2), O (20,2), H (0.02), Fe(46,8), Ca (5,85), Mg (1,75), K (0,47), Na (0). 2: Ni (4,93), Cu (0), S (14,9), O (27,1), H (0,11), Fe (28,1), Ca (14,9), Mg (0), K (0), Na (1,61). The research conducted by using the method of scanning electron microscopy and the X-ray microanalysis showed that iron and sulfur are spread uniformly over the scanned area. Sulfur is absent in the inclusions containing Fe and Ni. There are areas, sizes 8 - 120 microns, strongly enriched by Fe. The inclusions of rectangular and rhomboid shapes sizes 8 - 15 microns contain Ni as the content of Fe increases. There were identified the inclusions having a high content of Cu, with a maximum concentration of Ni. The presence of native elements testifies to the reducing mode of ore formation processes. The phases, containing Cu ? Ni, have a complex composition: pentlandite (FeNiS2), chalcopyrite (CuFeS2), bornite (CuFeS4), nickelhexahydrite (NiSO4 [6H2O]), wroewolfeite (Cu4 (OH) 6 (SO4) • 2H2O), pyrrhotine (Fe7S8), pyrite (FeS2). The position of the absorption lines in the magnetically ordered areas indicates the presence of stoichiometric FeS and CuFeS2. Some of the samples of this group have broadened lines, indicating the existence of various positions of the Fe ions in the sublattices. The ingrowths of CuFeS2 are characterized by the degree of the structure defectiveness, by various impurities, which is reflected in the studied parameters. As regards the other sample series, containing FeS and CuFeS2 in pyrrhotine matrix of Fe 1-xSx, the spectra are the superposition of the unsolved doublet, which shows the presence of paramagnetic areas. The magnetic phase has the spectrum composed of two six-linear spectrums. The peaks on the spectrum borders show the oxide presence. The isomer shifts of the samples range from 0 to 1.394 mm/s, quadrupole splitting ranges from 0 to 2.688 mm/s. This indicates that the local electronic structure depends on the genesis of compounds. Thus, most of the bulk of Cu, Ni is not dissipated in the crystal lattices of the ore, but it is part of the ore sulphides. The presence of the characteristic structures of the solid solutions decomposition shows a wide temperature range of sulphide crystallization.

Origin of Fe-Ti Oxide Mineralization in the Middle Paleoproterozoic Elet'ozero Syenite-Gabbro Intrusive Complex (Northern Karelia, Russia)

NASA Astrophysics Data System (ADS)

Sharkov, E. V.; Chistyakov, A. V.; Shchiptsov, V. V.; Bogina, M. M.; Frolov, P. V.

2018-03-01

Magmatic oxide mineralization widely developed in syenite-gabbro intrusive complexes is an important Fe and Ti resource. However, its origin is hotly debatable. Some researchers believe that the oxide ores were formed through precipitation of dense Ti-magnetite in an initial ferrogabbroic magma (Bai et al., 2012), whereas others consider them as a product of immiscible splitting of Fe-rich liquid during crystallization of Fe-Ti basaltic magma (Zhou et al., 2013). We consider this problem with a study of the Middle Paleoproterozoic (2086 ± 30 Ma) Elet'ozero Ti-bearing layered intrusive complex in northern Karelia (Baltic Shield). The first ore-bearing phase of the complex is mainly made up of diverse ferrogabbros, with subordinate clinopyroxenites and peridotites. Fe-Ti oxides (magnetite, Ti-magnetite, and ilmenite) usually account for 10-15 vol %, reaching 30-70% in ore varieties. The second intrusive phase is formed by alkaline and nepheline syenites. Petrographical, mineralogical, and geochemical data indicate that the first phase of the intrusion was derived from a moderately alkaline Fe-Ti basaltic melt, while the parental melt of the second phase was close in composition to alkaline trachyte. The orebodies comprise disseminated and massive ores. The disseminated Fe-Ti oxide ores make up lenses and layers conformable to general layering. Massive ores occur in subordinate amounts as layers and lenses, as well as cross-cutting veins. Elevated Nb and Ta contents in Fe-Ti oxides makes it possible to consider them complex ores. It is shown that the Fe-Ti oxide mineralization is related to the formation of a residual (Fe,Ti)-rich liquid, which lasted for the entire solidification history of the first intrusive phase. The liquid originated through multiple enrichment of Fe and Ti in the crystallization zone of the intrusion owing to the following processes: (1) precipitation of silicate minerals in the crystallization zone with a corresponding increase in the Fe and Ti contents in an interstitial melt; and (2) periodic accumulation of the residual melt in front of this zone. Unlike liquid immiscibility leading to melt splitting into two phases, this liquid dissolved the residual components of the melt. Correspondingly, such an Fe-rich liquid has unusual properties and requires further study.

Multistage deformation of Au-quartz veins (Laurieras, French Massif Central): evidence for late gold introduction from microstructural, isotopic and fluid inclusion studies

NASA Astrophysics Data System (ADS)

Essarraj, S.; Boiron, M.-C.; Cathelineau, M.; Fourcade, S.

2001-07-01

The relative chronology of fluid migration, quartz and Au-deposition in a silicified fault from the main Au-district (Laurieras, St Yrieix district) from northern French Massif Central has been determined from microstructural, fluid inclusion, isotopic and ore mineral evidences. Three main stages of fluid circulation, microfracturing and quartz crystallization, and ore deposition were distinguished on the basis of textural relationships and the pressure, temperature and composition of the palaeo-fluids: (1) a series of early fluid events was responsible for the localized drainage of retrograde metamorphic fluids along the main fault and the subsequent sealing by milky and microcrystalline quartz preceeded the main Au-ore stages. Early fluids were aqueous-carbonic, trapped under lithostatic to sublithostatic pressures at temperatures in the range 350-500°C. Subsequently, several types of microstructures were developed in the early quartz matrix. (2) NS microfractures filled by clear quartz, arsenopyrite and boulangerite (I) contain significant refractory gold concentrations. Clear quartz formed from aqueous-carbonic fluids of lower densities than those of the earlier fluids. Significant pressure drops, down to pressures around 55 MPa were responsible for a local immiscibility of the aqueous-carbonic fluids at temperatures of 340±20°C. (3) The main ore stage is characterized by the formation of dense sets of sub-vertical (EW) microfractures, healed fluid inclusion planes in quartz, and filled by ore minerals (native gold, galena and boulangerite II) when they crosscut earlier sulfides. The fluids are aqueous with low and decreasing salinity, and probable trapping temperatures around 230°C. Isotopic data, obtained on microfissured quartz, indicate these dilute aqueous fluids may be considered as meteoric waters that deeply infiltrated the crust. Late microfissuring of a mesothermal quartz vein, originally barren (only with pyrite and arsenopyrite), appears to be the main factor controlling gold enrichment. It can be related to late Hercynian deformational stages, disconnected from the early fault formation and silicification. These late stages which affected the Hercynian basement during its uplift, are of critical importance for the formation of Au-ores. We concluded that this type of Au-ore formed under rather shallow conditions, is distinct from those generally described in most mesothermal Au-veins.

Composition for detecting uranyl

DOEpatents

Baylor, L.C.; Stephens, S.M.

1994-01-01

The present invention relates to an indicator composition for use in spectrophotometric detection of a substance in a solution, and a method for making the composition. Useful indicators are sensitive to the particular substance being measured, but are unaffected by the fluid and other chemical species that may be present in the fluid. Optical indicators are used to measure the uranium concentration of process solutions in facilities for extracting uranium from ores, production of nuclear fuels, and reprocessing of irradiated fuels. The composition comprises an organohalide covalently bonded to an indicator for the substance, in such a manner that the product is itself an indicator that provides increased spectral resolution for detecting the substance. The indicator is preferably arsenazo III and the organohalide is preferably cyanuric chloride. These form a composition that is ideally suited for detecting uranyl.

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.

Application of a water cooling treatment and its effect on coal-based reduction of high-chromium vanadium and titanium iron ore

NASA Astrophysics Data System (ADS)

Yang, Song-tao; Zhou, Mi; Jiang, Tao; Guan, Shan-fei; Zhang, Wei-jun; Xue, Xiang-xin

2016-12-01

A water cooling treatment was applied in the coal-based reduction of high-chromium vanadium and titanium (V-Ti-Cr) iron ore from the Hongge region of Panzhihua, China. Its effects on the metallization ratio ( η), S removal ratio ( R S), and P removal ratio ( R P) were studied and analyzed on the basis of chemical composition determined via inductively coupled plasma optical emission spectroscopy. The metallic iron particle size and the element distribution of Fe, V, Cr, and Ti in a reduced briquette after water cooling treatment at 1350°C were determined and observed via scanning electron microscopy. The results show that the water cooling treatment improved the η, R S, and R P in the coal-based reduction of V-Ti-Cr iron ore compared to those obtained with a furnace cooling treatment. Meanwhile, the particle size of metallic iron obtained via the water cooling treatment was smaller than that of metallic iron obtained via the furnace cooling treatment; however, the particle size reached 70 μm at 1350°C, which is substantially larger than the minimum particle size required (20 μm) for magnetic separation. Therefore, the water cooling treatment described in this work is a good method for improving the quality of metallic iron in coal-based reduction and it could be applied in the coal-based reduction of V-Ti-Cr iron ore followed by magnetic separation.

Age and origin of base and precious metal veins of the Coeur d'Alene mining district, Idaho

USGS Publications Warehouse

Fleck, R.J.; Criss, R.E.; Eaton, G.F.; Cleland, R.W.; Wavra, C.S.; Bond, W.D.

2002-01-01

Ore-bearing quartz-carbonate veins of the Coeur d'Alene mining district yield 87Sr/86Sr ratios of 0.74 to >1.60 for low Rb/Sr, carbonate gangue minerals, similar to current ranges measured in Middle Proterozoic, high Rb/Sr rocks of the Belt Supergroup. Stable isotope and fluid inclusion studies establish a genetic relationship between vein formation and metamorphic-hydrothermal systems of the region. These extraordinary 87Sr/86Sr ratios require accumulation of radiogenic 87Sr in a high Rb/Sr system over an extended period prior to incorporation of Sr into the hydrothermal veins. Evaluation of the age and composition of potential sources of highly radiogenic Sr indicates that the ore-bearing veins of the Coeur d'Alene district formed during the Cretaceous from components scavenged from rocks of the Belt Supergroup, the primary host rocks of the district. Proterozoic Pb isotope ratios observed in galena from many Coeur d'Alene veins were established when Pb separated from uranium during deposition or diagenesis of the Belt Supergroup at 1400 to 1500 Ma, possibly as disseminated syngenetic deposits. K-Ar and Rb-Sr apparent ages and ??18O values of Belt Supergroup rocks decrease from the Coeur d'Alene district toward the Idaho and Kaniksu batholiths, approximately normal to the trends of metamorphic isograds, fold axes, foliation, and the major reverse faults of the district. Isoclinal folding, thrust faulting, high-temperature metamorphism, granitic plutonism, and regional-scale metamorphic-hydrothermal activity is documented in the region between 140 and 45 Ma, representing the only such combination of events in the Coeur d'Alene region subsequent to about 1300 Ma. The Sr and oxygen results and geologic evidence favor formation of the ore-bearing carbonate veins by fluids related to a complex metamorphic-hydrothermal system during the Cretaceous. Pb with Proterozoic isotopic compositions was probably mobilized and incorporated like other metals into the hydrothermal veins during this event. The ore-bearing veins were sheared and displaced during early Tertiary northwest-trending dextral strike-slip faulting along the Osburn fault and related structures of the Lewis and Clark line.

Escondida Mine, Chile

NASA Technical Reports Server (NTRS)

2001-01-01

[figure removed for brevity, see original site] Figure 1 Click on image for larger version

This ASTER image covers 30 by 37 km in the Atacama Desert, Chile and was acquired on April 23, 2000. The Escondida Cu-Au-Ag open-pit mine is at an elevation of 3050 m, and came on stream in 1990. Current capacity is 127,000 tons/day of ore; in 1999 production totaled 827,000 tons of copper, 150,000 ounces of gold and 3.53 million ounces of silver. Primary concentration of the ore is done on-site; the concentrate is then sent to the coast for further processing through a 170 km long, 9 pipe. Escondida is related geologically to three porphyry bodies intruded along the Chilean West Fissure Fault System. A high grade supergene cap overlies primary sulfide ore. This image is a conventional 3-2-1 RGB composite. Figure 1 displays SWIR bands 4-6-8 in RGB, and highlights lithologic and alteration differences of surface units. The image is located at 24.3 degrees south latitude and 69.1 degrees west longitude.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

The Effect Of Local Coal And Smelting Sponge Iron On Iron Content Of Pig Iron

NASA Astrophysics Data System (ADS)

Oediyani, Soesaptri; Juwita Sari, Pramita; Hadi P, Djoko

2018-03-01

The new regulation on mineral resources was announced by Ministry of Energy and Mineral resources (ESDM) of Indonesia at 2014 which it called Permen ESDM No 1/2014. Therefore, this research was conducted to add the value of local iron ores by using smelting technology. The objective of the research is to produce pig iron that meet the requirement of the new regulation of mineral resources such as 90% Fe. First, iron ores and coal mixed together with lime as a flux, then smelted in a Electric Arc Furnace at 1800°C. The process variables are (1; 1.25; 1.5; 1.75; 2.0) and the composition of coal (0.8%, 1.6%, 3.0%). The type of coal that used in this research was bituminous coal from Kalimantan and also the iron ores from Kalimantan. The products of the smelting technology are Pig iron and slag. Both pig iron and slag then analyzed by SEM-EDS to measure the iron content. The result shows that the maximum iron content on pig iron is about 95.04% meanwhile the minimum iron content on slag is about 3.66%. This result achieved at 1.6% coal and 2.0.

Preliminary lead isotope investigations of brine from the Red Sea, Galena from the Kingdom of Saudi Arabia, and galena from United Arab Republic (Egypt)

USGS Publications Warehouse

Delevaux, M.H.; Doe, B.R.; Brown, G.F.

1967-01-01

The isotopic composition of lead in Red Sea chloride brine containing 0.5 ppm Pb is found to be similar to that of some Cenozoic ore leads such as galena at Rabigh in Saudi Arabia that may have formed during mineralization accompanying Tertiary rifting. Bir Ranga galena in Miocene sediments from United Arab Republic (Egypt) is also isotopically similar to lead in Red Sea brine. The chlorine brine must be considered a possible mineralizing fluid. Lead isotopes show promise for use in mineral prospect evaluation in that galena from Samrah is isotopically similar to that from Mahd adh Dhahab, which has been the only ore producer in Saudi Arabia since 1945. Drilling at Samrah does indicate a possible economic mineralization. The lead isotope data coupled with available geologic knowledge and geochronometry are used to tentatively divide the ore prospects of the Kingdom of Saudi Arabia into relative categories of mineralization age. Two Mesozoic and Cenozoic mineralizations are distinguished on the basis of a 207Pb/204Pb difference; an early Paleozoic mineralization grouping is outlined; and a late Precambrian mineralization period is suggested. ?? 1967.

[NIR and XRD analysis of drill-hole samples from Zhamuaobao iron-graphite deposit, Inner Mongolia].

PubMed

Li, Ying-kui; Cao, Jian-jin; Wu, Zheng-quan; Dai, Dong-le; Lin, Zu-xu

2015-01-01

The author analyzed the 4202 drill-hole samples from Zhamuaobao iron-graphite deposit by using near infrared spectroscopy(NIR) and X-ray diffraction(XRD) measuring and testing techniques, and then compared and summarized the results of two kinds of testing technology. The results indicate that some difference of the mineral composition exists among different layers, the lithology from upper to deeper is the clay gravel layer of tertiary and quaternary, mudstone, mica quartz schist, quartz actinolite scarn, skarnization marble, iron ore deposits, graphite deposits and mica quartz schist. The petrogenesis in different depth also shows difference, which may indicate the geological characteristic to some extent. The samples had mainly undergone such processes as oxidization, carbonation, chloritization and skarn alteration. The research results can not only improve the geological feature of the mining area, but also have great importance in ore exploration, mining, mineral processing and so on. What's more, as XRD can provide preliminary information about the mineral composition, NIR can make further judgement on the existence of the minerals. The research integrated the advantages of both NIR and XRD measuring and testing techniques, put forward a method with two kinds of modern testing technology combined with each other, which may improve the accuracy of the mineral composition identification. In the meantime, the NIR will be more wildly used in geography on the basis of mineral spectroscopy.

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

NASA Astrophysics Data System (ADS)

Smith, Christopher N.; Kesler, Stephen E.; Blum, Joel D.; Rytuba, James J.

2008-05-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300 m) and silica-carbonate deposits that extend to depths of 1000 m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions ( δ202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although δ202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean δ202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ± 0.5‰) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO 2 vapor or reduction and volatilization of Hg (0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low δ202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems.

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

USGS Publications Warehouse

Smith, C.N.; Kesler, S.E.; Blum, J.D.; Rytuba, J.J.

2008-01-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300??m) and silica-carbonate deposits that extend to depths of 1000??m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions (??202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although ??202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean ??202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ?? 0.5???) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO2 vapor or reduction and volatilization of Hg(0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low ??202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems. ?? 2008 Elsevier B.V. All rights reserved.

Mineralogical, IR-spectral and geochemical monitoring of hydrothermal alteration in a deformed and metamorphosed Jurassic VMS deposit at Arroyo Rojo, Tierra del Fuego, Argentina

NASA Astrophysics Data System (ADS)

Biel, C.; Subías, I.; Acevedo, R. D.; Yusta, I.; Velasco, F.

2012-04-01

The Arroyo Rojo Zn-Pb-Cu volcanogenic massive sulfide deposit is the main deposit of the Fin del Mundo District in the Fuegian Andes, Argentina. This deposit is hosted by a Middle Jurassic volcanic and volcanoclastic sequence forming the Lemaire Formation. The latter consists, from the base up, of the following: rhyolitic and dacitic porphyritic rocks, ignimbrite, tuff, and flow. It is underlain by a pre-Jurassic basement and overlain by the hyaloclastic andesites of the Yahgán Formation. The Arroyo Rojo consists of stacked lenticular lenses that are associated with disseminated mineralization in both the footwall and the hanging wall. The internal structure of the ore lenses is marked by the occurrence of massive, semi-massive and banded facies, along with stringer and brecciated zones and minor ore disseminations. The mineral assemblage comprises mainly pyrite and sphalerite, with minor amounts of galena and chalcopyrite and rare pyrrhotite, arsenopyrite, tetrahedrite and bournonite. The ores and the volcanic host rocks have metamorphosed to greenschist facies and were overprinted by a penetrative tectonic foliation, which led to the development of mylonitic, and cataclastic textures, recrystallization and remobilization. Primary depositional characteristics and regional and hydrothermal alteration patterns were preserved despite deformation and metamorphism. Therefore, primary banding was preserved between facies boundaries. In addition, some remnants of magmatic origin are recognizable in preserved phenocrysts and volcaniclastic phenoclasts. Most of the volcanic and volcaniclastic rocks of the host sequence show a rhyolitic to rhyo-dacitic composition. Regional seafloor alteration, characterized by the presence of clinozoisite, Fe-chlorite and titanite, along with quartz and albite, is partially obliterated by hydrothermal alteration. The hydrothermal alteration is stratabound with the following assemblages, which developed from the base to top: (1) Quartz-Chlorite ± Sericite, (2) Quartz-Chlorite, (3) Chlorite ± Quartz-Sericite-Calcite, (4) Quartz-Chlorite ± Calcite and (5) Sericite + Quartz ± Chlorite ± Calcite. Magnesium-chlorite and phengitic white mica typically occur in the vicinity of the Arroyo Rojo ore lenses. To provide field criteria for exploration vectoring, the chemical composition of chlorite and the phengitic and paragonitic content of the white mica were determined and correlated with PIMA Fe-OH and Al-OH absorption wavelengths, respectively, relative to their proximity to the mineralized lenses. The results of this study can be used to help identify (1) felsic proximal facies associations, (2) ore horizons and (3) favorable hydrothermal alteration zones in other parts of the Fin del Mundo district.

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

Daugherty, W.; Mcwilliams, A.; Skidmore, E.

The 9975 Type B shipping package is used within the DOE complex for shipping special nuclear materials. This package is re-certified annually in accordance with Safety Analysis Report requirements. The package is also used at the Savannah River Site as part of the long-term storage configuration of special nuclear materials. As such, the packages do not undergo annual recertification during storage, with uncertainty as to how long some of the package components will meet their functional requirements in the storage environment. The packages are currently approved for up to 15 years storage, and work continues to provide a technical basismore » to extend that period. This paper describes efforts by the Savannah River National Laboratory (SRNL) to extend the service life estimate of Viton® GLT and GLT-S fluoroelastomer O-rings used in the 9975 shipping package. O-rings of both compositions are undergoing accelerated aging at elevated temperature, and are periodically tested for compression stress relaxation (CSR) behavior and leak performance. The CSR behavior of O-rings was evaluated at temperatures from 79 °C to 177 °C. These collective data were used to develop predictive models for extrapolation of CSR behavior to relevant service temperatures (< 75 °C). O-rings were also aged in Primary Containment Vessel (PCV) fixtures at temperatures ranging from 79 °C to 232 °C. The fixtures are helium leak tested periodically to determine if they remain leak-tight. The PCV fixture tests demonstrate that the 9975 O-rings will remain leak-tight at temperatures up to 149 °C for 3 years or more, and no leak failures have been observed with up to 8 years aging at 93 °C. Significantly longer periods of leak-tight service are expected at the lower temperatures actually experienced in the storage environment. The predictive model developed from the CSR data conservatively indicates a service life of more than 20 years at the bounding temperature of 75 °C. Although the relationship between CSR behavior and leak-tight performance has not been established for this design, the CSR predictions for this O-ring are conservative relative to leak-tight performance to date.« less

Four magnetite generations in the Precambrian Varena Iron Ore deposit, SE Lithuania, as a result of rock-fluid interactions

NASA Astrophysics Data System (ADS)

Skridlaite, Grazina; Prusinskiene, Sabina; Siliauskas, Laurynas

2017-04-01

Iron ores in Precambrian crystalline basement of the Varena area, SE Lithuania, were discovered during the detail geological-geophysical exploration in 1982-1992. They are covered with 210-500 m thick sediments. The Varena Iron Ore deposit (VIOD) may yield from 71 to 219.6 million tons of iron ore according to different economic evaluations (Marfin, 1996). They were assumed to be of metasomatic and hydrothermal origin, however several other hypotheses explaining the VIOZ origin, e.g. as a layered mafic or carbonatite intrusions were also suggested. Magnetites of the VIOD were thoroughly investigated by the Cameca SX100 microprobe at the Warsaw University and by the Quanta 250 Energy Dispersive Spectroscopy (EDS) at the Nature Research Centre in Vilnius, Lithuania. Four generations of magnetite were distinguished in the studied serpentine-magnetite ores (D8 drilling) and were compared with the earlier studied and reference magnetites. The earliest, spinel inclusion-rich magnetite cores (Mag-1) have the highest trace element contents (in wt%): Si (0.032), Al (0.167-0.248), Mg (0.340-0.405), Ti (0.215-0.254), V (0.090-0.138) etc. They might have formed during an early metamorphism and/or related skarn formation. Voluminous second magnetite (Mag-2) replacing olivine, pyroxenes, spinel and other skarn minerals at c. 540o C (Magnetite-Ilmenite geothermometer) has much lower trace element abundances, probably washed out by hydrothermal fluids. The latest magnetites (Mag-3 and Mag-4) overgrow the earlier ones and occur near or within the sulfide veins (Mag-4). As was observed from microtextures, the Mag-3 and Mag-4 have originated from the late thermal reworking by dissolution-reprecipitation processes. To imply an origin of the studied magnetites, they were compared to the earlier studied magmatic-metamorphic (1058 drilling), presumably skarn (982 drilling) magnetites from the studied area and plotted in the major magnetite ore type fields according to Dupuis and Beaudoin (2011). They have similar trace element abundances as skarn magnetites, e.g. are in general Ti-poor. The Mag-1 is more than twice richer in Mg than the porphyry and Kiruna type iron ores. A slight enrichment in Al, Ti and V because of spinel and ilmenite inclusions may have caused the earliest Mag-1 to resemble the porphyry type ores, while the secondary Mag-2 has Al, Ca and Mn contents as low as the Kiruna type ores. Thus, we can consider that fluid-rock interactions have strongly affected chemical compositions of the studied magnetites. Even though there are no precise age constructions for the metamorphic, metasomatic and hydrothermal iron ore formation process, they likely started later than 1.80 Ga (metamorphism of the host rocks; Bogdanova et al., 2015) and lasted until c. 1.50 Ga, when the rocks were intruded by the within-plate AMCG magmatic bodies. Bogdanova, S., Gorbatschev, R., Skridlaite, G., Soesoo, A., Taran, L., Kurlovich, D., 2015. Precambrian Research, 259, 5-33. Dupuis, C., Beaudoin, G., 2011. Mineral Deposita 46, 319-335. Marfinas, S., 1996. Report on the results of the evaluation of the Varena Iron Ore deposit, 2nd book, Vilnius.

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

NASA Astrophysics Data System (ADS)

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

2012-12-01

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

Thallium dispersal and contamination in surface sediments from South China and its source identification.

PubMed

Liu, Juan; Wang, Jin; Chen, Yongheng; Shen, Chuan-Chou; Jiang, Xiuyang; Xie, Xiaofan; Chen, Diyun; Lippold, Holger; Wang, Chunlin

2016-06-01

Thallium (Tl) is a non-essential element in humans and it is considered to be highly toxic. In this study, the contents, sources, and dispersal of Tl were investigated in surface sediments from a riverine system (the western Pearl River Basin, China), whose catchment has been contaminated by mining and roasting of Tl-bearing pyrite ores. The isotopic composition of Pb and total contents of Tl and other relevant metals (Pb, Zn, Cd, Co, and Ni) were measured in the pyrite ores, mining and roasting wastes, and the river sediments. Widespread contamination of Tl was observed in the sediments across the river, with the highest concentration of Tl (17.3 mg/kg) measured 4 km downstream from the pyrite industrial site. Application of a modified Institute for Reference Materials and Measurement (IRMM) sequential extraction scheme in representative sediments unveiled that 60-90% of Tl and Pb were present in the residual fraction of the sediments. The sediments contained generally lower (206)Pb/(207)Pb and higher (208)Pb/(206)Pb ratios compared with the natural Pb isotope signature (1.2008 and 2.0766 for (206)Pb/(207)Pb and (208)Pb/(206)Pb, respectively). These results suggested that a significant fraction of non-indigenous Pb could be attributed to the mining and roasting activities of pyrite ores, with low (206)Pb/(207)Pb (1.1539) and high (208)Pb/(206)Pb (2.1263). Results also showed that approximately 6-88% of Tl contamination in the sediments originated from the pyrite mining and roasting activities. This study highlights that Pb isotopic compositions could be used for quantitatively fingerprinting the sources of Tl contamination in sediments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and aerosol time-of-flight mass spectrometry (ATOFMS) single particle analysis of metallurgy plant emissions.

PubMed

Arndt, J; Deboudt, K; Anderson, A; Blondel, A; Eliet, S; Flament, P; Fourmentin, M; Healy, R M; Savary, V; Setyan, A; Wenger, J C

2016-03-01

The chemical composition of single particles deposited on industrial filters located in three different chimneys of an iron-manganese (Fe-Mn) alloy manufacturing plant have been compared using aerosol time-of-flight mass spectrometry (ATOFMS) and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX). Very similar types of particles were observed using both analytical techniques. Calcium-containing particles dominated in the firing area of the sintering unit, Mn and/or Al-bearing particles were observed at the cooling area of the sintering unit, while Mn-containing particles were dominant at the smelting unit. SEM-EDX analysis of particles collected downstream of the industrial filters showed that the composition of the particles emitted from the chimneys is very similar to those collected on the filters. ATOFMS analysis of ore samples was also performed to identify particulate emissions that could be generated by wind erosion and manual activities. Specific particle types have been identified for each emission source (chimneys and ore piles) and can be used as tracers for source apportionment of ambient PM measured in the vicinity of the industrial site. Copyright © 2015 Elsevier Ltd. All rights reserved.

Recent Advances and Research Status in Energy Conservation of Iron Ore Sintering in China

NASA Astrophysics Data System (ADS)

Wang, Yao-Zu; Zhang, Jian-Liang; Liu, Zheng-Jian; Du, Cheng-Bo

2017-11-01

For the ferrous burden of blast furnaces in China, sinter generally accounts for more than 70% and the sintering process accounts for approximately 6-10% of the total energy consumption of the iron and steel enterprise. Therefore, saving energy during the sintering process is important to reduce the energy consumption in the iron and steel industry. This paper aims to illustrate recent advances and the research status of energy conservation of iron ore sintering in China. It focuses on the development and application of energy-saving technologies such as the composite agglomeration process, sintering with high-proportion flue gas recirculation sintering, recovery of sensible heat from the sinter cooling process, homogeneous deep-bed sintering technology, and comprehensive treatment technology of leakage of sintering. Moreover, some suggestions for the future development of energy-saving technologies are put forward.

Phase composition of Katowice - Wełnowiec pytometallurgical slags: preliminary SEM study

NASA Astrophysics Data System (ADS)

Warchulski, Rafał; Szopa, Krzysztof

2014-09-01

Exploitation on Zn-Pb ores in Upper Silesia region dates back to the XIII century. Analyzed slags are associated with Hohenlohe smelting plant which started its work in 1804 as an iron smelter, and continued as zinc smelter since 1873. Waste material from smelting plant production was stored in Katowice - Wełnowiec, although nowadays most of it has been used for commercial purposes. Slags are composed of silicates and aluminosilicates, e.g. willemite, pyroxene- and melilite-group, K-feldspar accompanied by silico-phosphates close to perhamite, harrisonite and arsenate-chloride with composition similar to nealite. Chemical composition of most phases is simple with some unique substitutions in case of Sr and Ce

Phase Composition of Katowice - Wełnowiec Pytometallurgical Slags: Preliminary SEM Study

NASA Astrophysics Data System (ADS)

Warchulski, Rafał; Szopa, Krzysztof

2014-09-01

Exploitation on Zn-Pb ores in Upper Silesia region dates back to the XIII century. Analyzed slags are associated with Hohenlohe smelting plant which started its work in 1804 as an iron smelter, and continued as zinc smelter since 1873. Waste material from smelting plant production was stored in Katowice - Wełnowiec, although nowadays most of it has been used for commercial purposes. Slags are composed of silicates and aluminosilicates, e.g. willemite, pyroxene- and melilite-group, K-feldspar accompanied by silico-phosphates close to perhamite, harrisonite and arsenate-chloride with composition similar to nealite. Chemical composition of most phases is simple with some unique substitutions in case of Sr and Ce.

Petrogenesis and metallogenesis of the Wajilitag and Puchang Fe-Ti oxide-rich intrusive complexes, northwestern Tarim Large Igneous Province

NASA Astrophysics Data System (ADS)

Zhang, Dongyang; Zhang, Zhaochong; Huang, He; Cheng, Zhiguo; Charlier, Bernard

2018-04-01

The Wajilitag and Puchang intrusive complexes of the Tarim large igneous province (TLIP) are associated with significant resources of Fe-Ti oxide ores. These two mafic-ultramafic intrusions show differences in lithology and mineral chemistry. Clinopyroxenite and melagabbro are the dominant rock types in the Wajilitag complex, whereas the Puchang complex is generally gabbroic and anorthositic in composition with minor plagioclase-bearing clinopyroxenites in the marginal zone. Disseminated Fe-Ti oxide ores are found in the Wajilitag complex and closely associated with clinopyroxenites, whereas the Puchang complex hosts massive to disseminated Fe-Ti oxide ores mainly within its gabbroic rocks. The Wajilitag intrusive rocks are characterized by a restricted range of initial 87Sr/86Sr ratios (0.7038-0.7048) and positive εNd(t) (+0.04 - +3.01), indicating insignificant involvement of continental crustal contamination. The slightly higher initial 87Sr/86Sr ratios (0.7039-0.7059) and lower εNd(t) values (-1.05 - +2.35) of the Puchang intrusive rocks also suggest that the isotopic characteristics was controlled primarily by their mantle source, rather than by crustal contamination. Both complexes have Sr-Nd isotopic compositions close the neighboring kimberlitic rocks and their hosted mantle xenoliths in the TLIP. This indicates that the ferrobasaltic parental magmas were most probably originated from partial melting of a metasomatized subcontinental lithospheric mantle, modified recently with subduction-related materials by the impingement of the ascending mantle plume. The recycled subduction-related materials preserved in the lithospheric mantle could play a key role in the formation of the parental Fe-rich magmas in the context of an overall LIP system. The distinct variations in mineral assemblage for each complex and modeled results indicated that the Wajilitag and Puchang complexes experienced different crystallization path. Fe-Ti oxides in Wajilitag joined the liquidus earlier in the crystallization sequence, especially relative to the crystallization of plagioclase. This is attributed to the relatively high TFeO, TiO2 and initial H2O contents of the parental magma. In combination with definitive field and petrological evidence, the enrichment of highly incompatible elements (e.g., Zr, Hf, Nb and Ta) and the depletion of rare earth elements in the Fe-Ti oxide ores is consistent with the plausible interpretation that the ores could be formed by fractional crystallization and crystal accumulation of the Fe-Ti oxide crystals from the ferrobasaltic parental magmas. A considerable amount of the Fe-Ti oxides in the Puchang has transported and sunk from higher up in the chamber to the underlying unconsolidated silicate crystal pile. The highly dense Fe-Ti oxide crystal slurries further tended to effective accumulate Fe-Ti oxides to form high-grade Fe-Ti oxide ore bodies, and subsequent rapid collapse and intrusive into lower lithologies within the complex under a H2O-rich environment during the late-stage of magmatic differentiation. The development of massive Fe-Ti oxide ores in the case of the Puchang, could plausibly result from a combination of the protracted differentiation history of a Fe highly enriched parental magma and the later addition of external H2O from the country rocks (e.g., carbonates) to the slowly cooling magma chamber.

Production of Solar Cells in Space from Non Specific Ores by Utilization of Electronically Enhanced Sputtering

NASA Technical Reports Server (NTRS)

Curreri, Peter A.

2009-01-01

An ideal method of construction in space would utilize some form of the Universal Differentiator and Universal Constructor as described by Von Neumann (1). The Universal Differentiator is an idealized non ore specific extractive device which is capable of breaking any ore into its constituent elements, and the Universal Constructor can utilize these elements to build any device with controllability to the nanometer scale. During the Human Exploration Initiative program in the early 1990s a conceptual study was done (2) to understand whether such devices were feasible with near term technology for the utilization of space resources and energy. A candidate system was proposed which would utilize electronically enhanced sputtering as the differentiator. Highly ionized ions would be accelerated to a kinetic energy at which the interaction between them and the lattice elections in the ore would be at a maximum. Experiments have shown that the maximum disintegration of raw material occurs at an ion kinetic energy of about 5 MeV, regardless of the composition and structure of the raw material. Devices that could produce charged ion beams in this energy range in space were being tested in the early 1990s. At this energy, for example an ion in a beam of fluorine ions yields about 8 uranium ions from uranium fluoride, 1,400 hydrogen and oxygen atoms from ice, or 7,000 atoms from sulfur dioxide ice. The ions from the disintegrated ore would then be driven by an electrical field into a discriminator in the form of a mass spectrometer, where the magnetic field would divert the ions into collectors for future use or used directly in molecular beam construction techniques. The process would require 10-7 Torr vacuum which would be available in space or on the moon. If the process were used to make thin film silicon solar cells (ignoring any energy inefficiency for beam production), then energy break even for solar cells in space would occur after 14 days.

Mineralogical, textural, sulfur and lead isotope constraints on the origin of Ag-Pb-Zn mineralization at Bianjiadayuan, Inner Mongolia, NE China

NASA Astrophysics Data System (ADS)

Zhai, Degao; Liu, Jiajun; Cook, Nigel J.; Wang, Xilong; Yang, Yongqiang; Zhang, Anli; Jiao, Yingchun

2018-04-01

The Bianjiadayuan Ag-Pb-Zn deposit (4.81 Mt. @157.4 g/t Ag and 3.94% Pb + Zn) is located in the Great Hinggan Range Pb-Zn-Ag-Cu-Mo-Sn-Fe polymetallic metallogenic belt, NE China. Vein type Pb-Zn-Ag ore bodies are primarily hosted by slate, adjacent to a Sn ± Cu ± Mo mineralized porphyry intrusion. The deposit is characterized by silver-rich ores with Ag grades up to 3000 g/t. Four primary paragenetic sequences are recognized: (I) arsenopyrite + pyrite + quartz, (II) main sulfide + quartz, (III) silver-bearing sulfosalt + quartz, and (IV) boulangerite + calcite. A subsequent supergene oxidation stage has also been identified. Hydrothermal alteration consists of an early episode of silicification, two intermediate episodes (propylitic and phyllic), and a late argillic episode. Silver mineralization primarily belongs to the late paragenetic sequence III. Freibergite is the dominant and most important Ag-mineral in the deposit. Detailed ore mineralogy of Bianjiadayuan freibergite reveals evidence of chemical heterogeneity down to the microscale. Silver-rich sulfosalts in the late paragenetic sequence III are largely derived from a series of retrograde and solid-state reactions that redistribute Ag via decomposition and exsolution during cooling, illustrating that documentation of post-mineralization processes is essential for understanding silver ore formation. Sulfur and lead isotope compositions of sulfides, and comparison with those of local various geological units, indicate that the ore-forming fluids, lead, and other metals have a magmatic origin, suggesting a close genetic association between the studied Ag-Pb-Zn veins and the local granitic intrusion. Fluid cooling coupled with decreases in fO2 and fS2 are the factors inferred to have led to a decrease of silver solubility in the hydrothermal fluid, and successively promoted extensive Ag deposition.

Potential ecological and human health risks of heavy metals in surface soils associated with iron ore mining in Pahang, Malaysia.

PubMed

Diami, Siti Merryan; Kusin, Faradiella Mohd; Madzin, Zafira

2016-10-01

The composition of heavy metals (and metalloid) in surface soils of iron ore mine-impacted areas has been evaluated of their potential ecological and human health risks. The mining areas included seven selected locations in the vicinity of active and abandoned iron ore-mining sites in Pahang, Malaysia. Heavy metals such as Fe, Mn, Cu, Zn, Co, Pb, Cr, Ni, and Cd and metalloid As were present in the mining soils of the studied area, while Cu was found exceeding the soil guideline value at all sampling locations. However, the assessment of the potential ecological risk index (RI) indicated low ecological risk (RI between 44 and 128) with respect to Cd, Pb, Cu, As, Zn, Co, and Ni in the surface soils. Contributions of potential ecological risk [Formula: see text]by metal elements to the total potential ecological RI were evident for Cd, As, Pb, and Cu. Contribution of Cu appears to be consistently greater in the abandoned mining area compared to active iron ore-mining site. For non-carcinogenic risk, no significant potential health risk was found to both children and adults as the hazard indices (HIs) were all below than 1. The lifetime cancer risk (LCR) indicated that As has greater potential carcinogenic risk compared to other metals that may induce carcinogenic effects such as Pb, Cr, and Cd, while the LCR of As for children fell within tolerable range for regulatory purposes. Irrespective of carcinogenic or non-carcinogenic risk, greater potential health risk was found among children (by an order of magnitude higher for most metals) compared to adults. The hazard quotient (HQ) and cancer risk indicated that the pathways for the risk to occur were found to be in the order of ingestion > dermal > inhalation. Overall, findings showed that some metals and metalloid were still present at comparable concentrations even long after cessation of the iron ore-mining activities.

Application of Odor Sensors to Ore Sorting and Mill Feed Control

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

Michael G. Nelson

2005-08-01

Control of the feed provided to mineral processing facilities is a continuing challenge. Much effort is currently being devoted to overcoming these problems. These projects are usually described under the general headings of Mine-to-Mill Integration or Mine-Mill Optimization. It should be possible to combine the knowledge of ore type, mineralogy, and other characteristics (located in the mine modeling system), with the advanced capabilities of state-of-the-art mill control systems, to achieve an improved level of control in mineral processing that will allow optimization of the mill processes on an almost real-time basis. This is not happening because mill feed it ismore » often treated as a uniform material, when in reality it varies in composition and characteristics. An investigation was conducted to assess the suitability of odor sensors for maintaining traceability in ore production and processing. Commercially available sensors are now used in food processing, environmental monitoring, and other applications and can detect the presence of very small amounts (0.1-500 ppm) of some molecules. An assortment of such molecules could be used to ''tag'' blocks of ore as they are mined, according to their respective characteristics. Then, as the ore came into the mill, an array of ''electronic noses'' could be used to assess its characteristics in real time. It was found that the Cyranose 320{trademark}, a commercially available odor sensor, can easily distinguish among samples of rock marked with almond, cinnamon, citronella, lemon, and orange oils. Further, the sensor could detect mixtures of rocks marked with various combinations of these oils. Treatment of mixtures of galena and silica with odorant compounds showed no detrimental effects on flotation response in laboratory tests. Additional work is recommended to determine how this concept can be extended to the marking of large volumes of materials.« less

Mineral types of hydrothermal alteration zones in the Dukat ore field and their relationships to leucogranite and epithermal gold-silver ore, northeastern Russia

NASA Astrophysics Data System (ADS)

Filimonova, L. G.; Trubkin, N. V.; Chugaev, A. V.

2014-05-01

The paper considers the localization of potassic and propylitic hydrothermal alteration zones in the domal volcanic-plutonic structure controlling the position of the Dukat ore field with the eponymous unique epithermal Au-Ag deposit. Comprehensive mineralogical and geochemical data on rocks and minerals in hydrothermal alteration zones and associated intrusions have shown that quartz-jarosite-sericite, quartz-pyrite-sericite, and quartz-adularia-chlorite alterations were formed with the participation of fluid flows related to a fingerlike projection of a high-K leucogranite porphyry intrusion with large phenocrysts. These hydrothermal alterations developed in the rifted graben under conditions of divergent plate boundaries, whereas quartz-clinozoisite-calcite, epidote-chlorite, and garnet-calcite-chlorite alterations were linked to K-Na leucogranite intrusive bodies and developed under conditions of convergent plate boundaries reactivated as a result of formation of the marginal Okhotsk-Chukotka volcanic belt. Phase separation and coagulation of specific portions of ascending fluids resulted in the formation and stabilization of small-sized particles of native silver and other ore components, which enabled involvement in flows of secondary geothermal solutions and ore-forming fluids. The Sr, Nd, and Pb isotopic compositions of rocks and minerals from the hydrothermal alteration zones, associated intrusions, and economic orebodies at the Dukat deposit indicate that their components have been derived from the juvenile continental crust, which was altered in pre-Cretaceous periods of endogenic activity. The components of gangue minerals of potassic and propylitic hydrothertmal alterations and associated intrusions have been taken from deep sources differing in 87Sr/86Sr and 143Nd/144Nd at similar U/Pb and Th/Pb ratios. Chalcophile lead in products of hydrothermal activity and melanocratic inclusions in leucogranite has been taken from regions with elevated U/Pb and Th/Pb ratios.

Characterisation and Processing of Some Iron Ores of India

NASA Astrophysics Data System (ADS)

Krishna, S. J. G.; Patil, M. R.; Rudrappa, C.; Kumar, S. P.; Ravi, B. P.

2013-10-01

Lack of process characterization data of the ores based on the granulometry, texture, mineralogy, physical, chemical, properties, merits and limitations of process, market and local conditions may mislead the mineral processing entrepreneur. The proper implementation of process characterization and geotechnical map data will result in optimized sustainable utilization of resource by processing. A few case studies of process characterization of some Indian iron ores are dealt with. The tentative ascending order of process refractoriness of iron ores is massive hematite/magnetite < marine black iron oxide sands < laminated soft friable siliceous ore fines < massive banded magnetite quartzite < laminated soft friable clayey aluminous ore fines < massive banded hematite quartzite/jasper < massive clayey hydrated iron oxide ore < manganese bearing iron ores massive < Ti-V bearing magnetite magmatic ore < ferruginous cherty quartzite. Based on diagnostic process characterization, the ores have been classified and generic process have been adopted for some Indian iron ores.

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

NASA Astrophysics Data System (ADS)

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

2007-10-01

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

Genesis of Middle Miocene Yellowstone hotspot-related bonanza epithermal Au-Ag deposits, Northern Great Basin, USA

NASA Astrophysics Data System (ADS)

Saunders, J. A.; Unger, D. L.; Kamenov, G. D.; Fayek, M.; Hames, W. E.; Utterback, W. C.

2008-09-01

Epithermal deposits with bonanza Au-Ag veins in the northern Great Basin (NGB) are spatially and temporally associated with Middle Miocene bimodal volcanism that was related to a mantle plume that has now migrated to the Yellowstone National Park area. The Au-Ag deposits formed between 16.5 and 14 Ma, but exhibit different mineralogical compositions, the latter due to the nature of the country rocks hosting the deposits. Where host rocks were primarily of meta-sedimentary or granitic origin, adularia-rich gold mineralization formed. Where glassy rhyolitic country rocks host veins, colloidal silica textures and precious metal-colloid aggregation textures resulted. Where basalts are the country rocks, clay-rich mineralization (with silica minerals, adularia, and carbonate) developed. Oxygen isotope data from quartz (originally amorphous silica and gels) from super-high-grade banded ores from the Sleeper deposit show that ore-forming solutions had δ 18O values up to 10‰ heavier than mid-Miocene meteoric water. The geochemical signature of the ores (including their Se-rich nature) is interpreted here to reflect a mantle source for the “epithermal suite” elements (Au, Ag, Se, Te, As, Sb, Hg) and that signature is preserved to shallow crustal levels because of the similar volatility and aqueous geochemical behavior of the “epithermal suite” elements. A mantle source for the gold in the deposits is further supported by the Pb isotopic signature of the gold ores. Apparently the host rocks control the mineralization style and gangue mineralogy of ores. However, all deposits are considered to have derived precious metals and metalloids from mafic magmas related to the initial emergence of the Yellowstone hotspot. Basalt-derived volatiles and metal(loid)s are inferred to have been absorbed by meteoric-water-dominated geothermal systems heated by shallow rhyolitic magma chambers. Episodic discharge of volatiles and metal(loid)s from deep basaltic magmas mixed with heated meteoric water to create precious metal ore-forming fluids. Colloidal nanoparticles of Au-Ag alloy (electrum), naumannite (Ag2Se), silica, and adularia, likely nucleated at depth, traveled upward, and deposited where they grew large enough to aggregate along vein walls. Silica and gold colloids have been reported in hot springs from Yellowstone National Park, suggesting that such processes may continue to some extent to the present. However, it is possible that the initial development of the mantle plume led to a major but short-lived “distillation” process which led to the mid-Miocene bonanza ore-forming event.

Metallogeny of the Great Basin: crustal evolution, fluid flow, and ore deposits

USGS Publications Warehouse

Hofstra, Albert H.; Wallace, Alan R.

2006-01-01

The Great Basin physiographic province in the Western United States contains a diverse assortment of world-class ore deposits. It currently (2006) is the world's second leading producer of gold, contains large silver and base metal (Cu, Zn, Pb, Mo, W) deposits, a variety of other important metallic (Fe, Ni, Be, REE's, Hg, PGE) and industrial mineral (diatomite, barite, perlite, kaolinite, gallium) resources, as well as petroleum and geothermal energy resources. Ore deposits are most numerous and largest in size in linear mineral belts with complex geology. U.S. Geological Survey (USGS) scientists are in the final year of a research project initiated in the fall of 2001 to increase understanding of relations between crustal evolution, fluid flow, and ore deposits in the Great Basin. Because of its substantial past and current mineral production, this region has been the focus of numerous investigations over the past century and is the site of ongoing research by industry, academia, and state agencies. A variety of geoinformatic tools was used to organize, reinterpret, and display, in space and time, the large amounts of geologic, geophysical, geochemical, and hydrologic information deemed pertinent to this problem. This information, in combination with concentrated research on (1) critical aspects of the geologic history, (2) an area in northern Nevada that encompasses the major mineral belts, and (3) important mining districts and deposits, is producing new insights about the interplay between key tectonic events, hydrothermal fluid flow, and ore genesis in mineral belts. The results suggest that the Archean to Holocene history of the Great Basin was punctuated by several tectonic events that caused fluids of different origins (sea water, basinal brine, meteoric water, metamorphic water, magmatic water) to move through the crust. Basement faults reactivated during these events localized deformation, sedimentation, magmatism, and hydrothermal fluid flow in overlying rocks to form mineral belts that contain ore deposits of different types and ages that are locally superimposed (demonstrating inheritance). Fluid flow in these systems also was influenced by the distribution of permeable lithologies and paleotopographic highs and lows. Hydrothermal fluids evolved from their initial chemistries towards compositions that reflect the f O2 and f S2 buffering capacity of, and the ligands and metals present in, the rocks (?older mineralization) through which they moved. In northern Nevada, where gold deposits are relatively common, carbonaceous, pyritic strata buffered fluids of diverse origins to H2S-rich compositions so they could transport gold repeatedly over Paleozoic-Cenozoic time (convergent evolution). Ore formed where metal-laden fluids encountered effective physicochemical traps. Maps of Neogene basin fill and erosion surfaces identify areas where preexisting ore deposits have been progressively exposed or concealed. Comparisons with analogous terrains and deposit types in other parts of the world provide global context. The initial findings and some of the databases, geologic maps, sections, reconstructions, hydrogeologic models, topical syntheses, regional overviews, short courses, field guides, and deposit comparisons produced by project staff and associated managers, contractors, and collaborators have been presented in numerous abstracts, symposia, USGS publications, and professional journals over the last 5 years (see the extensive bibliography). Notable among these was the 2005 Geological Society of Nevada symposium in Reno, Nevada, and the 2005 Geological Society of America annual meeting in Salt Lake City, Utah, where project results were presented to audiences from around the nation and world. The final results of the project will be submitted for publication in 2007 to appropriate USGS and professional journals. A special issue of GEOSPHERE, scheduled for publication in 2007, will be devoted to the results o

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

NASA Astrophysics Data System (ADS)

Akhtar, Shamim; Yang, Xiaoyong; Pirajno, Franco

2017-09-01

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

Le gisement Ag sbnd Hg de Zgounder (Jebel Siroua, Anti-Atlas, Maroc) : un épithermal néoprotérozoïque de type Imiter

NASA Astrophysics Data System (ADS)

Marcoux, Éric; Wadjinny, Ahmed

2005-12-01

The Zgounder ore deposit (Anti-Atlas, Morocco), is hosted in a PII-PIII Proterozoic volcanosedimentary series. Disseminated mineralization is dominated by mercuriferous native silver (2 to 30 wt.% Hg), with few silver sulfosalts (acanthite, pearceite), arsenopyrite and base-metal sulfides. Arsenic grade of arsenopyrite and homogenisation temperatures of fluid inclusions indicate initial conditions of high temperature (above 400 °C). Lead isotope compositions comfort a Late-Proterozoic age and a crustal origin for metals. Similarities are obvious with the neighbouring silver ore deposit of Imiter and lead to consider Zgounder as another example of Neoproterozoic epithermal deposit in the Anti-Atlas of Morocco, a region that appears more and more as a silver metallogenic province. To cite this article: É. Marcoux, A. Wadjinny, C. R. Geoscience 337 (2005).

Sources of lead and zinc associated with metal smelting activities in the Trail area, British Columbia, Canada.

PubMed

Goodarzi, Fariborz; Sanei, Hamed; Labonté, Marcel; Duncan, William F

2002-06-01

The spatial distribution and deposition of lead and zinc emitted from the Trail smelter, British Columbia, Canada, was studied by strategically locating moss bags in the area surrounding the smelter and monitoring the deposition of elements every three months. A combined diffusion/distribution model was applied to estimate the relative contribution of stack-emitted material and material emitted from the secondary sources (e.g., wind-blown dust from ore/slag storage piles, uncovered transportation/trucking of ore, and historical dust). The results indicate that secondary sources are the major contributor of lead and zinc deposited within a short distance from the smelter. Gradually, the stack emissions become the main source of Pb and Zn at greater distances from the smelter. Typical material originating from each source was characterized by SEM/EDX, which indicated a marked difference in their morphology and chemical composition.

Review of the use of magnetic concentrates in geochemical exploration

USGS Publications Warehouse

Overstreet, W.C.; Day, G.W.

1985-01-01

Magnetic concentrates recovered readily by hand magnet from alluvial sediments or panned concentrates have been used successfully in exploration as a geochemical sample medium for Cu, Zn, Co, Cr, Mo, Ni, V, Sn, and Be, particularly in arid environments where alluvial sediments may be contaminated by aeolian debris. Opportunity for this use arose recently as chemical and spectrographic techniques were developed to determine the abundances of a variety of trace elements in Fe-rich media. The use of analytical data from magnetic concentrates was introduced as one of several anomaly-enhancement techniques based on heavy minerals and intended to identify blind ore deposits. An extensive literature, reviewed here, on the relation of the chemical composition of the mineral magnetite, a main component of magnetic concentrates, to geologic conditions of origin, facilitates the interpretation of trace-element data in the context of association with ore deposits.

Effects of Na2SO4 on iron and nickel reduction in a high-iron and low-nickel laterite ore

NASA Astrophysics Data System (ADS)

Wang, Xiao-ping; Sun, Ti-chang; Chen, Chao; Kou, Jue

2018-04-01

This study investigates the reactions of Na2SO4 and its effects on iron and nickel reduction in the roasting of a high-iron and low-nickel laterite ore through gas composition, X-ray diffraction, and scanning electron microscope analyses. Results showed that a reduction reaction of Na2SO4 to SO2 was performed with roasting up to 600°C. However, no clear influence on iron and nickel reductions appeared, because only a small amount of Na2SO4 reacted to produce SO2. Na2SO4 reacted completely at 1000°C, mainly producing troilite and nepheline, which remarkably improves selective reduction of nickel. Furthermore, the production of low-melting-point minerals, including troilite and nepheline, accelerated nickel reduction and delayed iron reduction, which is attributed to the concurrent production of magnesium magnetite, whose structure is more stable than the structure of magnetite. Reduction reactions of Na2SO4 resulted in weakening of the reduction atmosphere, and the main product of Na2SO4 changed and delayed the reduction of iron. Eventually, iron metallization was effectively controlled during laterite ore reduction roasting, leading to iron mainly being found in wustite and high iron-containing olivine.

Escondida Mine, Chile

NASA Technical Reports Server (NTRS)

2002-01-01

Full resolution visible and near-infrared image (1.4 MB) Full resolution shortwave infrared image (1.6 MB) This Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image covers 30 by 23 km (full images 30 x 37 km) in the Atacama Desert, Chile, and was acquired on April 23, 2000. The Escondida copper, gold, and silver open-pit mine is at an elevation of 3050 m, and began operations in 1990. Current capacity is 127,000 tons/day of ore; in 1999 production totaled 827,000 tons of copper, 150,000 ounces of gold, and 3.53 million ounces of silver. Primary concentrate of the ore is done on-site; the concentrate is then sent to the coast for further processing through a 170 km long, 9-inch pipe. Escondida is related geologically to three porphyry bodies intruded along the Chilean West Fissure Fault System. A high grade supergene cap overlies primary sulfide ore. The top image is a conventional 3-2-1 (near infrared, red, green) RGB composite. The bottom image displays shortwave infrared bands 4-6-8 (1.65um, 2.205um, 2.33um) in RGB, and highlights the different rock types present on the surface, as well as the changes caused by mining. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

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.

Geology and geochemistry of jasperoids from the Gold Bar district, Nevada

USGS Publications Warehouse

Yigit, O.; Hofstra, A.H.; Hitzman, M.W.; Nelson, E.P.

2006-01-01

Gold Bar is one of several Carlin-type gold mining districts located in the Battle Mountain-Eureka trend, Nevada. It is composed of one main deposit, Gold Bar; five satellite deposits; and four resources that contain 1.6 Moz (50 t) of gold. All of the deposits and resources occur at the intersection of north-northwest- and northeast-trending high-angle faults in slope facies limestones of the Devonian Nevada Group exposed in windows through Ordovician basin facies siliciclastic rocks of the Roberts Mountains allochthon. Igneous intrusions and magnetic anomalies are notably absent. The Gold Bar district contains a variety of discordant and stratabound jasperoid bodies, especially along the Wall Fault zone, that were mapped and studied in some detail to identify the attributes of those most closely associated with gold ore and to constrain genetic models. Four types of jasperoids, J0, J1, J2, and J3, were distinguished on the basis of their geologic and structural settings and appearance. Field relations suggest that J0 formed during an early event. Petrographic observations, geochemistry, and ??18O values of quartz suggest it was overprinted by the hydrothermal event that produced ore-related J1, J2, and J3 jasperoids and associated gold deposits. The greater amount of siliciclastic detritus present in J0 jasperoids caused them to have higher ??18O values than J1,2,3 jasperoids hosted in underlying limestones. Ore-related jasperoids are composed of main-ore-stage replacements and late-ore-stage open-space filling quartz with variable geochemistry and an enormous range of ??18O values (24.5 and -3.7???). Jasperoids hosted in limestones with the most anomalous Au, Ag, Hg, ??(As, Sb, Tl) concentrations and the highest ??18O values are associated with the largest deposits. The 28??? range of jasperoid ??18O values is best explained by mixing between an 18O-enriched fluid and an 18O-depleted fluid. The positive correlation between the sizes of gold deposits and the ??18O composition of jasperoids indicates that gold was introduced by the 18O-enriched fluid. The lowest calculated ??18O value for water in equilibrium with late-ore-stage quartz at 200??C (-15???) and the measured ??D value of fluid inclusion water extracted from late-ore-stage orpiment and realgar (-116???) indicate that the 18O-depleted fluid was composed of relatively unexchanged meteoric water. The source of the 18O-enriched ore fluid is not constrained. The ??34S values of late-ore-stage realgar, orpiment, and stibnite (5.7-15.5???) and barite (31.5-40.9???) suggest that H2S and sulfate were derived from sedimentary sources. Likewise, the ??13C and ??18O values of late-stage calcite (-4.8 to 1.5??? and 11.5 to 17.4???, respectively) suggest that CO2 was derived from marine limestones. Based on these data and the apparent absence of any Eocene intrusions in the district, Gold Bar may be the product of a nonmagmatic hydrothermal system. ?? Springer-Verlag 2006.

A new indicator mineral methodology based on a generic Bi-Pb-Te-S mineral inclusion signature in detrital gold from porphyry and low/intermediate sulfidation epithermal environments in Yukon Territory, Canada

NASA Astrophysics Data System (ADS)

Chapman, R. J.; Allan, M. M.; Mortensen, J. K.; Wrighton, T. M.; Grimshaw, M. R.

2017-12-01

Porphyry-epithermal and orogenic gold are two of the most important styles of gold-bearing mineralization within orogenic belts. Populations of detrital gold resulting from bulk erosion of such regions may exhibit a compositional continuum wherein Ag, Cu, and Hg in the gold alloy may vary across the full range exhibited by natural gold. This paper describes a new methodology whereby orogenic and porphyry-epithermal gold may be distinguished according to the mineralogy of microscopic inclusions observed within detrital gold particles. A total of 1459 gold grains from hypogene, eluvial, and placer environments around calc-alkaline porphyry deposits in Yukon (Nucleus-Revenue, Casino, Sonora Gulch, and Cyprus-Klaza) have been characterized in terms of their alloy compositions (Au, Ag, Cu, and Hg) and their inclusion mineralogy. Despite differences in the evolution of the different magmatic hydrothermal systems, the gold exhibits a clear Bi-Pb-Te-S mineralogy in the inclusion suite, a signature which is either extremely weak or (most commonly) absent in both Yukon orogenic gold and gold from orogenic settings worldwide. Generic systematic compositional changes in ore mineralogy previously identified across the porphyry-epithermal transition have been identified in the corresponding inclusion suites observed in samples from Yukon. However, the Bi-Te association repeatedly observed in gold from the porphyry mineralization persists into the epithermal environment. Ranges of P-T-X conditions are replicated in the geological environments which define generic styles of mineralization. These parameters influence both gold alloy composition and ore mineralogy, of which inclusion suites are a manifestation. Consequently, we propose that this methodology approach can underpin a widely applicable indicator methodology based on detrital gold.

Nitrile O-ring Cracking: A Case of Vacuum Flange O-ring Failures

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

Dees, Craig

2016-07-01

A review of recent nitrile O-ring failures in ISO-KF vacuum flange connections in glovebox applications is presented. An investigation of a single “isolated” o-ring failure leads to the discovery of cracked nitrile o-rings in a glovebox atmospheric control unit. The initial cause of the o-ring failure is attributed to ozone degradation. However, additional investigation reveals nitrile o-ring cracking on multiple gloveboxes and general purpose piping, roughly 85% of the nitrile o-rings removed for inspection show evidence of visible cracking after being in service for 18 months or less. The results of material testing and ambient air testing is presented, elevatedmore » ozone levels are not found. The contributing factors of o-ring failure, including nitrile air sensitivity, inadequate storage practices, and poor installation techniques, are discussed. A discussion of nitrile o-ring material properties, the benefits and limitations, and alternate materials are discussed. Considerations for o-ring material selection, purchasing, storage, and installation are presented in the context of lessons learned from the nitrile o-ring cracking investigation. This paper can be presented in 20 minutes and does not require special accommodations or special audio visual devices.« less

Paragenesis and chemistry of multistage tourmaline formation in the sullivan Pb-Zn-Ag deposit, British Columbia

USGS Publications Warehouse

Jiang, S.-Y.; Palmer, M.R.; Slack, J.F.; Shaw, D.R.

1998-01-01

Detailed petrographic study, scanning electron microscope imaging, and electron microprobe analyses of tourmalines from the Sullivan Pb-Zn-Ag massive sulfide deposit (British Columbia, Canada) document multiple paragenetic stages and large compositional variations. The tourmalines mainly belong to two common solid-solution series: dravite-schorl and dravite-uvite. Ca- and Fe-rich feruvite and alkali-deficient tourmalines are present locally. Products of tourmaline-forming stages include (from oldest to youngest): (1) rare Fe-rich dravite-schorl within black tourmalinite clasts in footwall fragmental rocks; (2) widespread Mg-rich, very fine grained, felted dravite in the footwall (the main type of tourmaline in the footwall tourmalinite pipe); (3) recrystallized, Fe-rich dravite-schorl (locally Ca-Fe feruvite) in the tourmalinite pipe, which preferentially occurs near postore gabbroic intrusions; (4) Mg-rich dravite or uvite associated with chlorite-pyrrhotite and chlorite-albite-pyrite-altered rocks in the shallow footwall and hanging wall; (5) discrete Mg-rich tourmaline grains associated with chlorite and discordant Mg-rich tourmaline rims which occur on disseminated Fe-rich schorl in the bedded Pb-Zn-Ag ores. The timing of rare Fe-rich schorl in the bedded ores is uncertain, but it most likely occurred during or between stages 2 and 3. The different paragenetic stages and their respective tourmaline compositions are interpreted in terms of a multistage evolution involving contributions from: (1) variable mixtures of synsedimentary, Fe-rich hydrothermal fluids and entrained seawater; (2) postore, Fe-rich, gabbro-related hydrothermal fluids; and (3) postore metamorphic reactions. Early synsedimentary, Fe-rich hydrothermal fluids which contained little or no entrained seawater formed Fe-rich black tourmalinite clasts locally in the footwall. The major type of tourmaline in the footwall tourmalinite pipe is Mg rich, recording seawater entrainment under high water/rock conditions, rather than control by the chemical composition of the original host sediments. Rare Fe-rich schorl within the bedded Pb-Zn-Ag ores is believed to have formed on the sea floor by reaction of an Fe-rich brine pool with detrital aluminous sediments. Postore emplacement of gabbro sills and local dikes in the footwall produced Fe-rich hydrothermal fluids, which were responsible for formation of minor Fe-rich dravite-schorl which overprinted earlier dravite. Postore, but synsedimentary, hydrothermal alteration involving entrained seawater was responsible for deposition of dravite and uvite in the hanging wall and for dravite in the brown tourmalinites of the shallow footwall. Mg-rich dravite-uvite associated with chlorite and in discordant rims on schorl in the bedded ores formed by sulfide-silicate reactions during greenschist facies regional metamorphism.

The mangazeya Ag-Pb-Zn vein deposit hosted in sedimentary rocks, Sakha-Yakutia, Russia: Mineral assemblages, fluid inclusions, stable isotopes (C, O, S), and origin

NASA Astrophysics Data System (ADS)

Anikina, E. Yu.; Bortnikov, N. S.; Klubnikin, G. K.; Gamyanin, G. N.; Prokof'ev, V. Yu.

2016-05-01

The succession of mineral assemblages, chemistry of gangue and ore minerals, fluid inclusions, and stable isotopes (C, O, S) in minerals have been studied in the Mangazeya silver-base-metal deposit hosted in terrigenous rocks of the Verkhoyansk Fold-Thrust Belt. The deposit is localized in the junction zone of the Kuranakh Anticlinorium and the Sartanga Synclinorium at the steep eastern limb of the Endybal Anticline. The deposit is situated at the intersection of the regional Nyuektame and North Tirekhtyakh faults. Igneous rocks are represented by the Endybal massif of granodiorite porphyry 97.8 ± 0.9 Ma in age and dikes varying in composition. One preore and three types of ore mineralization separated in space are distinguished: quartz-pyrite-arsenopyrite (I), quartz-carbonate-sulfide (II), and silver-base-metal (III). Quartz and carbonate (siderite) are predominant in ore veins. Ore minerals are represented by arsenopyrite, pyrite, sphalerite, galena, fahlore, and less frequent sulfosalts. Three types of fluid inclusions in quartz differ in phase compositions: two- or three-phase aqueous-carbon dioxide (FI I), carbon dioxide gas (FI II), and two-phase (FI III) containing liquid and a gas bubble. The homogenization temperature and salinity fall within the ranges of 367-217°C and 13.8-2.6 wt % NaCl equiv in FI I; 336-126°C and 15.4-0.8 wt % NaCl equiv in FI III. Carbon dioxide in FI II was homogenized in gas at +30.2 to +15.3°C and at +27.2 to 29.0°C in liquid. The δ34S values for minerals of type I range from-1.8 to +4.7‰ (V-CDT); of type II, from-7.4 to +6.6‰; and of type III, from-5.6 to +7.1‰. δ13C and δ18O vary from-7.0 to-6.7‰ (V-PDB) and from +16.6 to +17.1 (V-SMOW) in siderite-I; from-9.1 to-6.9‰ (V-PDB) and from +14.6 to +18.9 (V-SMOW) in siderite-II; from-5.4 to-3.1‰ (V-PDB) and from +14.6 to +19.5 (V-SMOW) in ankerite; and from-4.2 to-2.9‰ (V-PDB) and from +13.5 to +16.8 (V-SMOW) in calcite. The data on mineral assemblages, fluid inclusions, and ratios of stable isotopes allow us to speak about the formation of the Mangazeya deposit in relation to the activity of the hydrothermal-magmatic system. The latter combines emplacement of subvolcanic granitic stocks and involvement of fluids variable in salinity and temperature in ore deposition zone. The fluids released from crystallizing felsic magma and were formed in a convective cell by heating of meteoric and marine waters. The mechanism of ore deposition is related to phase separation (boiling) and mixing of fluids.

Design and Development of Lightweight Composite Tanks for the Mars Ascent Propulsion Technology

NASA Technical Reports Server (NTRS)

Estrada, Hector

1999-01-01

The investigation presented here focuses on the design and development of lightweight composite tanks for the Mars ascent propulsion technology. The proposed tanks are fabricated using the filament winding technique. The tanks will be used in the experimental permeability characterization of composite pressure vessels pressurized using cryogenic and kerosene fluids. We considered the geometry and composite material tailorability in the preliminary design formulation to obtain an isotensoid tank. The design formulation is based on membrane shell analysis. The tanks also include circular openings at the apex of the end caps for the installation of polar bosses. The development of a polar boss system was also investigated, and led to an innovative polar boss system that applies a uniform pressure on the o-ring gaskets. The permeability of these tanks was also considered and recommendations for improvement are presented.

The Management of Lead Concentrate Acquisition in "Trepca"

NASA Astrophysics Data System (ADS)

Haxhiaj, Ahmet; Fan, Maoming; Haxhiaj, Bajram

Based on the placement of lead and its consumption in industry branches, the paper deals with the composition of lead in the ores of Kopaonik, grinding and flotation recovery of galena. In the flotation process, the flotation machine, the flotation reagents, chemical composition of the flotation concentrates and tailings were discussed in this paper. Verification of the chemical composition of Pb concentrates with Pb, Zn, and Ag, etc. was conducted in this study. It is special that the ratio of Pb to Zn in Kopaonik massive composition is 1.4:1.0. During the flotation, lead tends to float with concentrate more than allowed. In this investigation, effects have been made to minimize the loss of Pb to concentrates. This paper as such gave the first effects in optimizing of these parameters with positive effects in the flotation process in Trepca.

The chemistry of hydrothermal magnetite: a review

USGS Publications Warehouse

Nadoll, Patrick; Angerer, Thomas; Mauk, Jeffrey L.; French, David; Walshe, John

2014-01-01

Magnetite (Fe3O4) is a well-recognized petrogenetic indicator and is a common accessory mineral in many ore deposits and their host rocks. Recent years have seen an increased interest in the use of hydrothermal magnetite for provenance studies and as a pathfinder for mineral exploration. A number of studies have investigated how specific formation conditions are reflected in the composition of the respective magnetite. Two fundamental questions underlie these efforts — (i) How can the composition of igneous and, more importantly, hydrothermal magnetite be used to discriminate mineralized areas from barren host rocks, and (ii) how can this assist exploration geologists to target ore deposits at greater and greater distances from the main mineralization? Similar to igneous magnetite, the most important factors that govern compositional variations in hydrothermal magnetite are (A) temperature, (B) fluid composition — element availability, (C) oxygen and sulfur fugacity, (D) silicate and sulfide activity, (E) host rock buffering, (F) re-equilibration processes, and (G) intrinsic crystallographic controls such as ionic radius and charge balance. We discuss how specific formation conditions are reflected in the composition of magnetite and review studies that investigate the chemistry of hydrothermal and igneous magnetite from various mineral deposits and their host rocks. Furthermore, we discuss the redox-related alteration of magnetite (martitization and mushketovitization) and mineral inclusions in magnetite and their effect on chemical analyses. Our database includes published and previously unpublished magnetite minor and trace element data for magnetite from (1) banded iron formations (BIF) and related high-grade iron ore deposits in Western Australia, India, and Brazil, (2) Ag–Pb–Zn veins of the Coeur d'Alene district, United States, (3) porphyry Cu–(Au)–(Mo) deposits and associated (4) calcic and magnesian skarn deposits in the southwestern United States and Indonesia, and (5) plutonic igneous rocks from the Henderson Climax-type Mo deposit, United States, and the un-mineralized Inner Zone Batholith granodiorite, Japan. These five settings represent a diverse suite of geological settings and cover a wide range of formation conditions. The main discriminator elements for magnetite are Mg, Al, Ti, V, Cr, Mn, Co, Ni, Zn, and Ga. These elements are commonly present at detectable levels (10 to > 1000 ppm) and display systematic variations. We propose a combination of Ni/(Cr + Mn) vs. Ti + V, Al + Mn vs. Ti + V, Ti/V and Sn/Ga discriminant plots and upper threshold concentrations to discriminate hydrothermal from igneous magnetite and to fingerprint different hydrothermal ore deposits. The overall trends in upper threshold values for the different settings can be summarized as follows: (I) BIF (hydrothermal) — low Al, Ti, V, Cr, Mn, Co, Ni, Zn, Ga and Sn; (II) Ag–Pb–Zn veins (hydrothermal) — high Mn and low Ga and Sn; (III) Mg-skarn (hydrothermal) — high Mg and Mn and low Al, Ti, Cr, Co, Ni and Ga; (IV) skarn (hydrothermal) — high Mg, Al, Cr, Mn, Co, Ni and Zn and low Sn; (V) porphyry (hydrothermal) — high Ti and V and low Sn; (VI) porphyry (igneous) — high Ti, V and Cr and low Mg; and (VII) Climax-Mo (igneous) — high Al, Ga and Sn and low Mg and Cr.

ACES. Accelerated Corrosion Expert Simulator

DTIC Science & Technology

2010-02-01

Composites Coating Systems Organic Inorganic Ceramic Materials 22 Inputs and Dimensions Xi Thickness Hardness Strength Ductility Abrasion Resistance...GPU 25 T-Handle Latch 10-Year ACT Material/ Coating Configuration Die Cast Zinc T-Handle Carbon Steel Pin CS Shank CS T-Washer Carbon Steel Dish E- coat ...CARC Zinc Plating Cadmium Plated BoltE- coat /CARC CS Panel CS Panel O-Ring E- coat /CARC Original (10-year ACT) Design Green Flag Color Qualitative

Use and legacy of mercury in the Andes.

PubMed

Cooke, Colin A; Hintelmann, Holger; Ague, Jay J; Burger, Richard; Biester, Harald; Sachs, Julian P; Engstrom, Daniel R

2013-05-07

Both cinnabar (HgS) and metallic mercury (Hg(0)) were important resources throughout Andean prehistory. Cinnabar was used for millennia to make vermillion, a red pigment that was highly valued in pre-Hispanic Peru; metallic Hg(0) has been used since the mid-16th century to conduct mercury amalgamation, an efficient process of extracting precious metals from ores. However, little is known about which cinnabar deposits were exploited by pre-Hispanic cultures, and the environmental consequences of Hg mining and amalgamation remain enigmatic. Here we use Hg isotopes to source archeological cinnabar and to fingerprint Hg pollution preserved in lake sediment cores from Peru and the Galápagos Islands. Both pre-Inca (pre-1400 AD) and Colonial (1532-1821 AD) archeological artifacts contain cinnabar that matches isotopically with cinnabar ores from Huancavelica, Peru, the largest cinnabar-bearing district in Central and South America. In contrast, the Inca (1400-1532 AD) artifacts sampled are characterized by a unique Hg isotopic composition. In addition, preindustrial (i.e., pre-1900 AD) Hg pollution preserved in lake sediments matches closely the isotopic composition of cinnabar from the Peruvian Andes. Industrial-era Hg pollution, in contrast, is distinct isotopically from preindustrial emissions, suggesting that pre- and postindustrial Hg emissions may be distinguished isotopically in lake sediment cores.

Discovery of Ni-smectite-rich saprolite at Loma Ortega, Falcondo mining district (Dominican Republic): geochemistry and mineralogy of an unusual case of "hybrid hydrous Mg silicate - clay silicate" type Ni-laterite

NASA Astrophysics Data System (ADS)

Tauler, Esperança; Lewis, John F.; Villanova-de-Benavent, Cristina; Aiglsperger, Thomas; Proenza, Joaquín A.; Domènech, Cristina; Gallardo, Tamara; Longo, Francisco; Galí, Salvador

2017-10-01

Hydrous Mg silicate-type Ni-laterite deposits, like those in the Falcondo district, Dominican Republic, are dominated by Ni-enriched serpentine and garnierite. Recently, abundant Ni-smectite in the saprolite zone have been discovered in Loma Ortega, one of the nine Ni-laterite deposits in Falcondo. A first detailed study on these Ni-smectites has been performed (μXRD, SEM, EPMA), in addition to a geochemical and mineralogical characterisation of the Loma Ortega profile (XRF, ICP-MS, XRD). Unlike other smectite occurrences in laterite profiles worldwide, the Loma Ortega smectites are trioctahedral and exhibit high Ni contents never reported before. These Ni-smectites may be formed from weathering of pyroxene and olivine, and their composition can be explained by the mineralogy and the composition of the Al-depleted, olivine-rich parent ultramafic rock. Our study shows that Ni-laterites are mineralogically complex, and that a hydrous Mg silicate ore and a clay silicate ore can be confined to the same horizon in the weathering profile, which has significant implications from a recovery perspective. In accordance, the classification of "hybrid hydrous Mg silicate - clay silicate" type Ni-laterite deposit for Loma Ortega would be more appropriate.

High-rate behaviour of iron ore pellet

NASA Astrophysics Data System (ADS)

Gustafsson, Gustaf; Häggblad, Hans-Åke; Jonsén, Pär; Nishida, Masahiro

2015-09-01

Iron ore pellets are sintered, centimetre-sized spheres of ore with high iron content. Together with carbonized coal, iron ore pellets are used in the production of steel. In the transportation from the pelletizing plants to the customers, the iron ore pellets are exposed to different loading situations, resulting in degradation of strength and in some cases fragmentation. For future reliable numerical simulations of the handling and transportation of iron ore pellets, knowledge about their mechanical properties is needed. This paper describes the experimental work to investigate the dynamic mechanical properties of blast furnace iron ore pellets. To study the dynamic fracture of iron ore pellets a number of split Hopkinson pressure bar tests are carried out and analysed.

Phosphorite-hosted zinc and lead mineralization in the Sekarna deposit (Central Tunisia)

USGS Publications Warehouse

Garnit, Hechmi; Bouhel, Salah; Barca, Donatella; Johnson, Craig A.; Chtara, Chaker

2012-01-01

The Sekarna Zn–Pb deposit is located in Central Tunisia at the northeastern edge of the Cenozoic Rohia graben. Mineralization comprises two major ore types: (1) disseminated Zn–Pb sulfides that occur as lenses in sedimentary phosphorite layers and (2) cavity-filling zinc oxides (calamine-type ores) that crosscut Late Cretaceous and Early Eocene limestone. We studied Zn sulfide mineralization in the Saint Pierre ore body, which is hosted in a 5-m-thick sedimentary phosphorite unit of Early Eocene age. The sulfide mineralization occurs as replacements of carbonate cement in phosphorite. The ores comprise stratiform lenses rich in sphalerite with minor galena, Fe sulfides, and earlier diagenetic barite. Laser ablation–inductively coupled plasma mass spectrometry analyses of sphalerite and galena show a wide range of minor element contents with significant enrichment of cadmium in both sphalerite (6,000–20,000 ppm) and galena (12–189 ppm). The minor element enrichments likely reflect the influence of the immediate organic-rich host rocks. Fluid inclusions in sphalerite give homogenization temperatures of 80–130°C. The final ice melting temperatures range from −22°C to −11°C, which correspond to salinities of 15–24 wt.% NaCl eq. and suggest a basinal brine origin for the fluids. Sulfur isotope analyses show uniformly negative values for sphalerite (−11.2‰ to −9.3‰) and galena (−16‰ to −12.3‰). The δ34S of barite, which averages 25.1‰, is 4‰ higher than the value for Eocene seawater sulfate. The sulfur isotopic compositions are inferred to reflect sulfur derivation through bacterial reduction of contemporaneous seawater sulfate, possibly in restricted basins where organic matter was abundant. The Pb isotopes suggest an upper crustal lead source.

Phosphorite-hosted zinc and lead mineralization in the Sekarna deposit (Central Tunisia)

NASA Astrophysics Data System (ADS)

Garnit, Hechmi; Bouhlel, Salah; Barca, Donatella; Johnson, Craig A.; Chtara, Chaker

2012-06-01

The Sekarna Zn-Pb deposit is located in Central Tunisia at the northeastern edge of the Cenozoic Rohia graben. Mineralization comprises two major ore types: (1) disseminated Zn-Pb sulfides that occur as lenses in sedimentary phosphorite layers and (2) cavity-filling zinc oxides (calamine-type ores) that crosscut Late Cretaceous and Early Eocene limestone. We studied Zn sulfide mineralization in the Saint Pierre ore body, which is hosted in a 5-m-thick sedimentary phosphorite unit of Early Eocene age. The sulfide mineralization occurs as replacements of carbonate cement in phosphorite. The ores comprise stratiform lenses rich in sphalerite with minor galena, Fe sulfides, and earlier diagenetic barite. Laser ablation-inductively coupled plasma mass spectrometry analyses of sphalerite and galena show a wide range of minor element contents with significant enrichment of cadmium in both sphalerite (6,000-20,000 ppm) and galena (12-189 ppm). The minor element enrichments likely reflect the influence of the immediate organic-rich host rocks. Fluid inclusions in sphalerite give homogenization temperatures of 80-130°C. The final ice melting temperatures range from -22°C to -11°C, which correspond to salinities of 15-24 wt.% NaCl eq. and suggest a basinal brine origin for the fluids. Sulfur isotope analyses show uniformly negative values for sphalerite (-11.2‰ to -9.3‰) and galena (-16‰ to -12.3‰). The δ34S of barite, which averages 25.1‰, is 4‰ higher than the value for Eocene seawater sulfate. The sulfur isotopic compositions are inferred to reflect sulfur derivation through bacterial reduction of contemporaneous seawater sulfate, possibly in restricted basins where organic matter was abundant. The Pb isotopes suggest an upper crustal lead source.

Remnant colloform pyrite at the haile gold deposit, South Carolina: A textural key to genesis

USGS Publications Warehouse

Foley, N.; Ayuso, R.A.; Seal, R.R.

2001-01-01

Auriferous iron sulfide-bearing deposits of the Carolina slate belt have distinctive mineralogical and textural features-traits that provide a basis to construct models of ore deposition. Our identification of paragenetically early types of pyrite, especially remnant colloform, crustiform, and layered growth textures of pyrite containing electrum and pyrrhotite, establishes unequivocally that gold mineralization was coeval with deposition of host rocks and not solely related to Paleozoic tectonic events. Ore horizons at the Haile deposit, South Carolina, contain many remnants of early pyrite: (1) fine-grained cubic pyrite disseminated along bedding; (2) fine- grained spongy, rounded masses of pyrite that may envelop or drape over pyrite cubes; (3) fragments of botryoidally and crustiform layered pyrite, and (4) pyritic infilling of vesicles and pumice. Detailed mineral chemistry by petrography, microprobe, SEM, and EDS analysis of replaced pumice and colloform structures containing both arsenic compositional banding and electrum points to coeval deposition of gold and the volcanic host rocks and, thus, confirms a syngenetic origin for the gold deposits. Early pyrite textures are present in other major deposits of the Carolina slate belt, such as Ridgeway and Barite Hill, and these provide strong evidence for models whereby the sulfide ores formed prior to tectonism. The role of Paleozoic metamorphism was to remobilize and concentrate gold and other minerals in structurally prepared sites. Recognizing the significance of paragenetically early pyrite and gold textures can play an important role in distinguishing sulfide ores that form in volcanic and sedimentary environments from those formed solely by metamorphic processes. Exploration strategies applied to the Carolina slate belt and correlative rocks in the eastern United States in the Avalonian basement will benefit from using syngenetic models for gold mineralization.

Host-rock controlled epigenetic, hydrothermal metasomatic origin of the Bayan Obo REEFe-Nb ore deposit, Inner Mongolia, P.R.C.

USGS Publications Warehouse

Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Yinchen, R.

1992-01-01

Bayan Obo, a complex rare earth element (REE)FeNb ore deposit, located in Inner Mongolia, P.R.C. is the world's largest known REE deposit. The deposit is chiefly in a marble unit (H8), but extends into an overlying unit of black shale, slate and schist unit (H9), both of which are in the upper part of the Middle Proterozoic Bayan Obo Group. Based on sedimentary structures, the presence of detrital quartz and algal fossil remains, and the 16-km long geographic extent, the H8 marble is a sedimentary deposit, and not a carbonatite of magmatic origin, as proposed by some previous investigators. The unit was weakly regionally metamorphosed (most probably the lower part of the green schist facies) into marble and quartzite prior to mineralization. Tectonically, the deposit is located on the northern flank of the Sino-Korean craton. Many hypotheses have been proposed for the origin of the Bayan Obo deposit; the studies reported here support an epigenetic, hydrothermal, metasomatic origin. Such an origin is supported by field and laboratory textural evidence; 232Th/208Pb internal isochron mineral ages of selected monazite and bastnaesite samples; 40Ar/39Ar incremental heating minimum mineral ages of selected alkali amphiboles; chemical compositions of different generations of both REE ore minerals and alkali amphiboles; and evidence of host-rock influence on the various types of Bayan Obo ores. The internal isochron ages of the REE minerals indicate Caledonian ages for various episodes of REE and Fe mineralization. No evidence was found to indicate a genetic relation between the extensive biotite granitic rocks of Hercynian age in the mine region and the Bayan Obo are deposit, as suggested by previous workers. ?? 1992.

Automated Quantitative Rare Earth Elements Mineralogy by Scanning Electron Microscopy

NASA Astrophysics Data System (ADS)

Sindern, Sven; Meyer, F. Michael

2016-09-01

Increasing industrial demand of rare earth elements (REEs) stems from the central role they play for advanced technologies and the accelerating move away from carbon-based fuels. However, REE production is often hampered by the chemical, mineralogical as well as textural complexity of the ores with a need for better understanding of their salient properties. This is not only essential for in-depth genetic interpretations but also for a robust assessment of ore quality and economic viability. The design of energy and cost-efficient processing of REE ores depends heavily on information about REE element deportment that can be made available employing automated quantitative process mineralogy. Quantitative mineralogy assigns numeric values to compositional and textural properties of mineral matter. Scanning electron microscopy (SEM) combined with a suitable software package for acquisition of backscatter electron and X-ray signals, phase assignment and image analysis is one of the most efficient tools for quantitative mineralogy. The four different SEM-based automated quantitative mineralogy systems, i.e. FEI QEMSCAN and MLA, Tescan TIMA and Zeiss Mineralogic Mining, which are commercially available, are briefly characterized. Using examples of quantitative REE mineralogy, this chapter illustrates capabilities and limitations of automated SEM-based systems. Chemical variability of REE minerals and analytical uncertainty can reduce performance of phase assignment. This is shown for the REE phases parisite and synchysite. In another example from a monazite REE deposit, the quantitative mineralogical parameters surface roughness and mineral association derived from image analysis are applied for automated discrimination of apatite formed in a breakdown reaction of monazite and apatite formed by metamorphism prior to monazite breakdown. SEM-based automated mineralogy fulfils all requirements for characterization of complex unconventional REE ores that will become increasingly important for supply of REEs in the future.

Mixing from below in hydrothermal ore deposits

NASA Astrophysics Data System (ADS)

Bons, Paul D.; Gomez-Rivas, Enrique; Markl, Gregor; Walter, Bejamin

2014-05-01

Unconformity-related hydrothermal ore deposits typically show indications of mixing of two end-member fluids: (a) hot, deep, rock-buffered basement brines and (b) colder fluids derived from the surface or overlying sediments. The hydromechanics of bringing these fluids together from above and below remain unclear. Classical percolative Darcy-flow models are inconsistent with (1) fluid overpressure indicated by fracturing and brecciation, (2) fast fluid flow indicated by thermal disequilibrium, and (3) strong fluid composition variations on the mm-scale, indicated by fluid inclusion analyses (Bons et al. 2012; Fusswinkel et al. 2013). We propose that fluids first descend, sucked down by desiccation reactions in exhumed basement. Oldest fluids reach greatest depths, where long residence times and elevated temperatures allow them the extensively equilibrate with their host rock, reach high salinity and scavenge metals, if present. Youngest fluids can only penetrate to shallower depths and can (partially) retain signatures from their origin, for example high Cl/Br ratios from the dissolution of evaporitic halite horizons. When fluids are released from all levels of the crustal column, these fluids mix during rapid ascent to form hydrothermal ore deposits. Mixing from below provides a viable hydromechanical mechanism to explain the common phenomenon of mixed shallow and deep fluids in hydrothermal ore deposits. Bons, P.D., Elburg, M.A., Gomez-Rivas, E. 2012. A review of the formation of tectonic veins and their microstructures. J. Struct. Geol. doi:10.1016/j.jsg.2012.07.005 Fusswinkel, T., Wagner, T., Wälle, M., Wenzel, T., Heinrich, C.A., Markl, M. 2013. Fluid mixing forms basement-hosted Pb-Zn deposits: Insight from metal and halogen geochemistry of individual fluid inclusions. Geology. doi:10.1130/G34092.1

Historical records of atmospheric Pb deposition in four Scottish ombrotrophic peat bogs: An isotopic comparison with other records from western Europe and Greenland - article no. GB2016

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

Cloy, J.M.; Farmer, J.G.; Graham, M.C.

2008-05-15

Cores collected from ombrotrophic peat bogs in west central, east central, northeast and southwest Scotland were dated (C-14, Pb-210) and analyzed (ICP-OES, ICP-MS) to derive and compare their historical records of atmospheric anthropogenic Pb deposition over the past 2500 years. On the basis of Pb isotopic composition (e. g., Pb-206/Pb-207), clear indications of Pb contamination during the pre-Roman/Roman, post-Roman and medieval periods were attributed to the mining and smelting of Pb ores from Britain and elsewhere in Europe. Between the 17th and early 20th centuries, during the industrial period, the mining and smelting of indigenous Scottish Pb ores were themore » most important sources of anthropogenic Pb deposition at three of the sites. In contrast, at the most southerly site, influences from the use of both British Pb ores and imported Australian Pb ores (in more southern parts of Britain) since the late 19th century were evident. At each of the sites, Australian-Pb-influenced car exhaust emissions (from the 1930s to late 1990s), along with significant contributions from coal combustion (until the late 1960s and onset of the post industrial period), were evident. Atmospheric anthropogenic Pb deposition across Scotland was greatest (similar to 10 to 40 mg m{sup -2} a{sup -1}) between the late 1880s and late 1960s, increasing southward, declining to 0.44 to 5.7 mg m{sup 2} a{sup -1} by the early 2000s.« less

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... mercury ore subcategory. 440.40 Section 440.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The provisions...

40 CFR 440.10 - Applicability; description of the iron ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ore subcategory. 440.10 Section 440.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions of...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The...

40 CFR 440.10 - Applicability; description of the iron ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ore subcategory. 440.10 Section 440.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions of...

40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The...

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The...

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The...

40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The...

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... nickel ore subcategory. 440.70 Section 440.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The provisions...

40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The...

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... mercury ore subcategory. 440.40 Section 440.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The provisions...

40 CFR 440.10 - Applicability; description of the iron ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ore subcategory. 440.10 Section 440.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions of...

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... nickel ore subcategory. 440.70 Section 440.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The provisions...

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... mercury ore subcategory. 440.40 Section 440.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The provisions...

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The...

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... nickel ore subcategory. 440.70 Section 440.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The provisions...

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

Code of Federal Regulations, 2012 CFR

2012-01-01

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

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

Code of Federal Regulations, 2011 CFR

2011-01-01

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

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

Code of Federal Regulations, 2013 CFR

2013-01-01

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

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

Code of Federal Regulations, 2014 CFR

2014-01-01

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

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The provisions of this...

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of this...

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of this...

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The provisions of this...

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... nickel ore subcategory. 440.70 Section 440.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The provisions of this subpart...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The provisions of this...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The provisions of this...

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The provisions of this...

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... nickel ore subcategory. 440.70 Section 440.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The provisions of this subpart...

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... mercury ore subcategory. 440.40 Section 440.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The provisions of subpart D...

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The provisions of this...

40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The provisions of this...

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of this subpart K are applicable to discharges from (a) mines that produce platinum ore and (b...

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of this subpart K are applicable to discharges from (a) mines that produce platinum ore and (b...

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of this subpart K are applicable to discharges from (a) mines that produce platinum ore and (b...

36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ...

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

36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ORE BOAT. BY LATE WINTER, THE ORE STORAGE YARD SEEN AT LEFT WILL BE DEPLETED. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the vanadium ore...

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the vanadium ore...

8. EAST ELEVATION OF SKIDOO MILL AND UPPER ORE BIN, ...

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

8. EAST ELEVATION OF SKIDOO MILL AND UPPER ORE BIN, LOOKING WEST FROM ACCESS ROAD. THE ROADWAY ON THIS LEVEL (CENTER) WAS USED FOR UNLOADING ORE BROUGHT ON BURROWS INTO THE ORE BIN AT THE TOP LEVEL OF THE MILL. THE ORE BIN IN THE UPPER LEFT WAS ADDED LATER WHEN ORE WAS BROUGHT TO THE MILL BY TRUCKS. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

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

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

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

1959-10-31

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

DETAIL VIEW OF LOWER TRAM TERMINAL, SECONDARY ORE BIN, CRUSHER ...

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

DETAIL VIEW OF LOWER TRAM TERMINAL, SECONDARY ORE BIN, CRUSHER FOUNDATION, AND BALL MILL FOUNDATIONS, LOOKING NORTH NORTHWEST. ORE FROM THE MINES WAS DUMPED FROM THE TRAM BUCKETS INTO THE PRIMARY ORE BIN UNDER THE TRAM TERMINAL. A SLIDING CONTROL DOOR INTRODUCED THE INTO THE JAW CRUSHER (FOUNDATIONS,CENTER). THE CRUSHED ORE WAS THEN CONVEYED INTO THE SECONDARY ORE BIN AT CENTER LEFT. A HOLE IN THE FLOOR OF THE ORE BIN PASSED ORE ONTO ANOTHER CONVEYOR THAT BROUGHT IT OUT TO THE BALL MILL(FOUNDATIONS,CENTER BOTTOM). THIS SYSTEM IS MOST LIKELY NOT THE ORIGINAL SET UP, PROBABLY INSTALLED IN THE MINE'S LAST OCCUPATION IN THE EARLY 1940s. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

Solvent extraction of diatomite

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

Williams, W.

1984-07-24

There is provided a method of extracting hydrocarbons from a diatomite ore. The particle size of the ore is first reduced to form a processed ore. The processed ore is then mixed with a substantially irregular granular material to form an unstratified ore mixture having increased permeability to an extracting solvent. The unstratified ore mixture is then permeated with an extracting solvent to obtain a hydrocarbon-solvent stream from which hydrocarbons are subsequently separated. The irregular granular material may be sand.

25. FRONT END LOADERS MOMENTARILY IN REPOSE IN THE ORE ...

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

25. FRONT END LOADERS MOMENTARILY IN REPOSE IN THE ORE STORAGE YARD. AN ORE BRIDGE THAT FORMERLY TRANSFERRED ORE WITHIN THE STORAGE YARD WAS DESTROYED BY A BLIZZARD IN 1978. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

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

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

A unique ore-placer cluster with high-Hg gold mineralization in the Amur region (Russia)

NASA Astrophysics Data System (ADS)

Stepanov, V. A.; Moyseenko, V. G.; Melnikov, A. V.

2017-02-01

This work presents the geological structure and a description of gold-ore manifestations and gold placers in the Un'ya-Bom ore-placer cluster of the Amur gold-bearing province. The host rocks are Late Paleozoic and Mesozoic black-shale formations. Intrusive formations are rare. The sublatitudinal Un'ya thrust fault, along which Paleozoic sandstones overlap Mesozoic flyschoid deposits, is regarded as an orecontrolling structure. Gold-quartz and low-sulfide ores are confined to quartz-vein zones. Ore minerals are arsenopyrite, scheelite, ferberite, galena, and native gold. Gold-ore manifestations and placers contain high-Hg native gold. The high Hg content in native gold is explained by the occurrence of the eroded frontal part of the gold-ore pipe in the ore cluster, a source of native gold.

Speciation and characterization of arsenic in gold ores and cyanidation tailings using X-ray absorption spectroscopy

USGS Publications Warehouse

Paktunc, D.; Foster, A.; Heald, S.; Laflamme, G.

2004-01-01

The knowledge of mineralogy and molecular structure of As is needed to better understand the stability of As in wastes resulting from processing of gold ores. In this study, optical microscopy, scanning electron microscopy, electron microprobe, X-ray diffraction and X-ray absorption fine structure (XAFS) spectroscopy (including both XANES and EXAFS regimes) were employed to determine the mineralogical composition and local coordination environment of As in gold ores and process tailings from bench-scale tests designed to mimic a common plant practice. Arsenic-bearing minerals identified in the ores and tailings include iron (III) oxyhydroxides, scorodite (FeAsO4??2H2O), ferric arsenates, arseniosiderite (Ca2Fe3 (AsO4)3O2??3H2O), Ca-Fe arsenates, pharmacosiderite (KFe4 (AsO4)3(OH)4??6-7H2O), jarosite (K2Fe6(SO4)4 (OH)12) and arsenopyrite (FeAsS). Iron (III) oxyhydroxides contain variable levels of As from trace to about 22 wt% and Ca up to approximately 9 wt%. Finely ground ore and tailings samples were examined by bulk XAFS and selected mineral grains were analyzed by microfocused XAFS (micro-EXAFS) spectroscopy to reconcile the ambiguities of multiple As sources in the complex bulk EXAFS spectra. XANES spectra indicated that As occurs as As5+in all the samples. Micro-EXAFS spectra of individual iron (III) oxyhydroxide grains with varying As concentrations point to inner-sphere bidentate-binuclear arsenate complexes as the predominant form of As. There are indications for the presence of a second Fe shell corresponding to bidentate-mononuclear arrangement. Iron (III) oxyhydroxides with high As concentrations corresponding to maximum adsorption densities probably occur as nanoparticles. The discovery of Ca atoms around As in iron (III) oxyhydroxides at interatomic distances of 4.14-4.17 A?? and the coordination numbers suggest the formation of arseniosiderite-like nanoclusters by coprecipitation rather than simple adsorption of Ca onto iron (III) oxyhydroxides. Correlation of Ca with As in iron (III) oxyhydroxides as determined by electron microprobe analysis supports the coprecipitate origin for the presence of Ca in iron (III) oxyhydroxides. The samples containing higher abundances of ferric arsenates released higher As concentrations during the cyanidation tests. The presence of highly soluble ferric arsenates and Ca-Fe arsenates, and relatively unstable iron (III) oxyhydroxides with Fe/As molar ratios of less than 4 in the ore and process tailings suggests that not only the tailings in the impoundment will continue to release As, but also there is the potential for mobilization of As from the natural sources such as the unmined ore. ?? 2004 Elsevier Ltd.

Speciation and characterization of arsenic in gold ores and cyanidation tailings using X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Paktunc, Dogan; Foster, Andrea; Heald, Steve; Laflamme, Gilles

2004-03-01

The knowledge of mineralogy and molecular structure of As is needed to better understand the stability of As in wastes resulting from processing of gold ores. In this study, optical microscopy, scanning electron microscopy, electron microprobe, X-ray diffraction and X-ray absorption fine structure (XAFS) spectroscopy (including both XANES and EXAFS regimes) were employed to determine the mineralogical composition and local coordination environment of As in gold ores and process tailings from bench-scale tests designed to mimic a common plant practice. Arsenic-bearing minerals identified in the ores and tailings include iron (III) oxyhydroxides, scorodite (FeAsO 4·2H 2O), ferric arsenates, arseniosiderite (Ca 2Fe 3(AsO 4) 3O 2·3H 2O), Ca-Fe arsenates, pharmacosiderite (KFe 4(AsO 4) 3(OH) 4·6-7H 2O), jarosite (K 2Fe 6(SO 4) 4(OH) 12) and arsenopyrite (FeAsS). Iron (III) oxyhydroxides contain variable levels of As from trace to about 22 wt% and Ca up to approximately 9 wt%. Finely ground ore and tailings samples were examined by bulk XAFS and selected mineral grains were analyzed by microfocused XAFS (micro-EXAFS) spectroscopy to reconcile the ambiguities of multiple As sources in the complex bulk EXAFS spectra. XANES spectra indicated that As occurs as As 5+in all the samples. Micro-EXAFS spectra of individual iron (III) oxyhydroxide grains with varying As concentrations point to inner-sphere bidentate-binuclear arsenate complexes as the predominant form of As. There are indications for the presence of a second Fe shell corresponding to bidentate-mononuclear arrangement. Iron (III) oxyhydroxides with high As concentrations corresponding to maximum adsorption densities probably occur as nanoparticles. The discovery of Ca atoms around As in iron (III) oxyhydroxides at interatomic distances of 4.14-4.17 Å and the coordination numbers suggest the formation of arseniosiderite-like nanoclusters by coprecipitation rather than simple adsorption of Ca onto iron (III) oxyhydroxides. Correlation of Ca with As in iron (III) oxyhydroxides as determined by electron microprobe analysis supports the coprecipitate origin for the presence of Ca in iron (III) oxyhydroxides. The samples containing higher abundances of ferric arsenates released higher As concentrations during the cyanidation tests. The presence of highly soluble ferric arsenates and Ca-Fe arsenates, and relatively unstable iron (III) oxyhydroxides with Fe/As molar ratios of less than 4 in the ore and process tailings suggests that not only the tailings in the impoundment will continue to release As, but also there is the potential for mobilization of As from the natural sources such as the unmined ore.

Blasting preparation for selective mining of complex structured ore deposition

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Ferruginous compounds in the airborne particulate matter of the metropolitan area of Belo Horizonte, Minas Gerais, Brazil.

PubMed

Tavares, Fernanda Vasconcelos Fonseca; Ardisson, José Domingos; Rodrigues, Paulo César Horta; Fabris, José Domingos; Fernandez-Outon, Luis Eugenio; Feliciano, Vanusa Maria Delage

2017-08-01

Samples of soil, iron ore, and airborne particulate matter (size <10 μm) were analyzed with the main goal of investigating the differentiating physicochemical properties of their ferruginous compounds. These data were used to identify whether the sources of airborne particulate matter in the metropolitan area of Belo Horizonte, Minas Gerais, Brazil, are either from natural origin, as, for instance, re-suspension of particles from soil, or due to anthropogenic activities, meaning that it would be originated from the many iron ore minings surrounding the metropolitan area. Numerical simulations were used to model the atmospheric dispersion of the airborne particulate matter emitted by iron mining located at the Iron Quadrangle geodomain, Minas Gerais. Results from these numerical simulations supported identifying the sites with the highest concentrations of airborne particulate matter in the metropolitan area. Samples of these suspended materials were collected at the selected sites by using high-volume air samplers. The physicochemical features of the solid materials were assessed by X-ray fluorescence, X-ray diffraction, magnetometry, and 57 Fe Mössbauer spectroscopy. The soil materials were found to be rich in quartz, aluminum, organic matter, and low contents of iron, mainly as low crystalline iron oxides. The samples of the iron ores, on the other hand, contain high concentration of iron, dominantly as relatively pure and crystalline hematite (α-Fe 2 O 3 ). The samples of the airborne particulate matter are rich in iron, mainly as hematite, but contained also quartz, aluminum, and calcium. Mössbauer spectroscopy was used to evaluate the hyperfine structure of 57 Fe of the hematite both from the iron ore and the soil samples. The structural characteristics of the hematite of these particulate materials were further explored. The direct influence of the iron ore mining on the composition of the airborne particulate matter was clearly evidenced based on the trace ability of hematite to its source of emission. Even the atmospheric air on regions relatively far away from the mining activities is also significantly influenced.

The carbonaceous phyllite rock-hosted Pedra Verde copper mine, Borborema Province, Brazil: Stable isotope constraints, structural controls and metallogenic evolution

NASA Astrophysics Data System (ADS)

da Silva Nogueira de Matos, José Henrique; Saraiva dos Santos, Ticiano José; Virgínia Soares Monteiro, Lena

2017-12-01

The Pedra Verde Copper Mine is located in the Viçosa do Ceará municipality, State of Ceará, NE Brazil. The copper mineralization is hosted by the Pedra Verde Phyllite, which is a carbonaceous chlorite-calcite phyllite with subordinate biotite. It belongs to the Neoproterozoic Martinópole Group of the Médio Coreaú Domain, Borborema Province. The Pedra Verde deposit is stratabound and its ore zoning is conspicuous, according to the following sequence, from bottom to top: marcasite/pyrite, native silver, chalcopyrite, bornite, chalcocite, native copper and hematite. Barite and carbonaceous material are reported in ore zones. Zoning reflects the ore formation within a redox boundary developed due to the interaction between oxidized copper- and sulfate-bearing fluids and the reduced phyllite. Structural control on mineralization is evidenced by the association of the ore minerals with veins, hinge folds, shadow pressures, and mylonitic foliation. It was mainly exercised by a dextral transcurrent shear zone developed during the third deformational stage identified in the Médio Coreaú Domain between 590 Ma and 570 Ma. This points to the importance of epigenetic, post-metamorphic deformational events for ore formation. Oxygen isotopic composition (δ18OH2O = 8.94 to 11.28‰, at 250 to 300 °C) estimated for the hydrothermal fluids in equilibrium with calcite indicates metamorphic or evolved meteoric isotopic signatures. The δ13CPDB values (-2.60 to -9.25‰) obtained for hydrothermal calcite indicate mixing of carbon sources derived from marine carbonate rocks and carbonaceous material. The δ34SCDT values (14.88 to 36.91‰) of sulfides suggest evaporites as sulfate sources or a closed system in relation to SO42- availability to form H2S. Carbonaceous matter had a key role in thermochemical sulfate processes and sulfide precipitation. The Pedra Verde Copper Mine is considered the first stratabound meta-sedimentary rock-hosted copper deposit described in Brazil and shares similarities with the syn-orogenic copper deposits of the Congo-Zambian Copperbelt formed during the Gondwana amalgamation.

Pb isotopic constraints on the formation of the Dikulushi Cu-Pb-Zn-Ag mineralisation, Kundelungu Plateau (Democratic Republic of Congo)

NASA Astrophysics Data System (ADS)

Haest, Maarten; Schneider, Jens; Cloquet, Christophe; Latruwe, Kris; Vanhaecke, Frank; Muchez, Philippe

2010-04-01

Base metal-Ag mineralisation at Dikulushi and in other deposits on the Kundelungu Plateau (Democratic Republic of Congo) developed during two episodes. Subeconomic Cu-Pb-Zn-Fe polysulphide ores were generated during the Lufilian Orogeny (c. 520 Ma ago) in a set of E-W- and NE-SW-oriented faults. Their lead has a relatively unradiogenic and internally inhomogeneous isotopic composition (206Pb/204Pb = 18.07-18.49), most likely generated by mixing of Pb from isotopically heterogeneous clastic sources. These sulphides were remobilised and enriched after the Lufilian Orogeny, along reactivated and newly formed NE-SW-oriented faults into a chalcocite-dominated Cu-Ag mineralisation of high economic interest. The chalcocite samples contain only trace amounts of lead and show mostly radiogenic Pb isotope signatures that fall along a linear trend in the 207Pb/204Pb vs. 206Pb/204Pb diagram (206Pb/204Pb = 18.66-23.65; 207Pb/204Pb = 15.72-16.02). These anomalous characteristics reflect a two-stage evolution involving admixture of both radiogenic lead and uranium during a young fluid event possibly c. 100 Ma ago. The Pb isotope systematics of local host rocks to mineralisation also indicate some comparable young disturbance of their U-Th-Pb systems, related to the same event. They could have provided Pb with sufficiently radiogenic compositions that was added to less radiogenic Pb remobilised from precursor Cu-Pb-Zn-Fe polysulphides, whereas the U most likely originated from external sources. Local metal sources are also suggested by the 208Pb/204Pb-206Pb/204Pb systematics of combined ore and rock lead, which indicate a pronounced and diversified lithological control of the immediate host rocks on the chalcocite-dominated Cu-Ag ores. The Pb isotope systematics of polysulphide mineralisation on the Kundelungu Plateau clearly record a diachronous evolution.

Garden soil and house dust as exposure media for lead uptake in the mining village of Stratoni, Greece.

PubMed

Argyraki, Ariadne

2014-08-01

The relationships between two exposure media, garden soil and house dust, were studied for Pb uptake in Stratoni village in northern Greece, an industrial area of mining and processing of sulphide ore. Lead data for the two media were assessed in terms of total and bioaccessible content, measurement and geochemical variability, and mineralogical composition. It was found that total Pb was enriched in house dust samples by a factor of 2 on average. Total Pb concentration in soil samples had a maximum of 2,040 mg/kg and reached a maximum of 7,000 mg/kg in house dust samples. The estimated variability due to measurement uncertainty was dominated by the sampling process, and the proportion of sampling variance was greater for soil samples, indicating a higher degree of Pb heterogeneity in soil on the given spatial scale of sampling strata. Although the same general spatial trend was observed for both sampling media with decreasing Pb concentration by increasing distance from the ore-processing plant, Pb in dust samples displayed the highest concentrations within a 300-600-m zone from the ore-processing facility. The significant differences which were observed in Pb speciation between the studied media were explained by differences in mineralogical composition of outdoor soil and indoor dust. Lead-enriched Fe and Mn oxides predominated in soil samples while fine galena grains (<10-20 μm diameter) were the major Pb-bearing phase in dust samples. The integrated exposure uptake biokinetic model was used to predict the risk of elevated blood lead levels in children of Stratoni. Model prediction indicated an average probability of 61 % for blood-Pb to exceed 10 μg/dl. The results underline the importance of house dust in risk assessment and highlight the effect of outdoor and indoor conditions on the fate of Pb in the particular environment of Stratoni.

46 CFR 97.12-1 - Bulk ores and similar cargoes.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Bulk ores and similar cargoes. 97.12-1 Section 97.12-1... OPERATIONS Cargo Stowage § 97.12-1 Bulk ores and similar cargoes. (a) The owners or operators of general cargo vessels which carry bulk cargoes such as ore, ore concentrates, and similar cargoes shall furnish...

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

Not Available

This paper is actually a composite of two papers dealing with automation and computerized control of underground mining equipment. The paper primarily discusses drills, haulage equipment, and tunneling machines. It compares performance and cost benefits of conventional equipment to the new automated methods. The company involved are iron ore mining companies in Scandinavia. The papers also discusses the different equipment using air power, water power, hydraulic power, and computer power. The different drill rigs are compared for performance and cost.

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore... are applicable to discharges from (a) mines, either open-pit or underground, that produce mercury ores...

5. Foreground: ore bridges, ore/coke/limestone bins, Detroit River; background: stock ...

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

5. Foreground: ore bridges, ore/coke/limestone bins, Detroit River; background: stock house on left, stripper building, BOF. Looking south/southwest - Rouge Steel Company, 3001 Miller Road, Dearborn, MI

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

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

13. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN ...

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

13. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN BUILT IN 1911-1912, THIS WAS THE LARGEST ORE-UNLOADING DOCK ON THE GREAT LAKES. THE DOCK FEATURED FOUR HULETT UNLOADERS, EACH WITH A BUCKET CAPACITY OF 17 TONS; A 15-TON CAPACITY ORE STOCKING AND REHANDLING BRIDGE; AND A ONE-MILLION-TON CAPACITY ORE STORAGE YARD. THE WILLIAM-SEAVER-MORGAN COMPANY OF CLEVELAND BUILT THE DOCK EQUIPMENT. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

Summary of the mineralogy of the Colorado Plateau uranium ores

USGS Publications Warehouse

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

1956-01-01

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

Chromite Ore from the Transvaal Region of South Africa

EPA Pesticide Factsheets

In 2001, EPA finalized a rule to to delete both chromite ore mined in the Transvaal Region of South Africa and the unreacted ore component of the chromite ore processing residue (COPR) from TRI reporting requirements.

26. NORTHERN VIEW OF ORE YARD WITH ORE BRIDGES IN ...

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

26. NORTHERN VIEW OF ORE YARD WITH ORE BRIDGES IN THE BACKGROUND. BLAST FURNACES ALONG THE RIGHT SIDE. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

A unique ore-placer area of the Amur region with high-Hg gold

NASA Astrophysics Data System (ADS)

Melnikov, A. V.; Stepanov, V. A.; Moiseenko, V. G.

2017-10-01

This work presents the geological structure and a description of the gold-ore occurrences and gold placers of the Un'ya-Bom ore-placer cluster of the Amur gold-bearing province. The host rocks are Late Paleozoic and Mesozoic black shales. Intrusive formations occur rarely. The sublatitudinal Un'ya Thrust is the principal ore-controlling structure. Paleozoic sandstones are thrust over Mesozoic flysch deposits along the Un'ya Thrust. The gold-ore occurrences are represented by quartz-vein zones. The ores are gold-quartz, low-sulfide. Ore minerals are arsenopyrite, scheelite, ferberite, galena, and native gold. High-Hg native gold was revealed in the ore occurrences and placers. The high Hg content in native gold is explained by the presence of the frontal part of the gold-bearing column located within the cluster; the rich placers were formed due to crushing of this column.

Virtual phosphorus ore requirement of Japanese economy.

PubMed

Matsubae, Kazuyo; Kajiyama, Jun; Hiraki, Takehito; Nagasaka, Tetsuya

2011-08-01

Phosphorus is indispensable for agricultural production. Hence, the consumption of imported food indirectly implies the import of phosphorus resources. The global consumption of agricultural products depends on a small number of ore-producing countries. For sustainable management of phosphorus resources, the global supply and demand network should be clarified. In this study, we propose the virtual phosphorus ore requirement as a new indicator of the direct and indirect phosphorus requirements for our society. The virtual phosphorus ore requirement indicates the direct and indirect demands for phosphorus ore transformed into agricultural products and fertilizer. In this study, the virtual phosphorus ore requirement was evaluated for the Japanese economy in 2005. Importantly, the results show that our society requires twice as much phosphorus ore as the domestic demand for fertilizer production. The phosphorus contained in "eaten" agricultural products was only 12% of virtual phosphorus ore requirement. Copyright © 2011 Elsevier Ltd. All rights reserved.

Prevalence and Risk Factors of Elevated Blood Lead in Children in Gold Ore Processing Communities, Zamfara, Nigeria, 2012.

PubMed

Kaufman, John A; Brown, Mary Jean; Umar-Tsafe, Nasir T; Adbullahi, Muhammad Bashir; Getso, Kabiru I; Kaita, Ibrahim M; Sule, Binta Bako; Ba'aba, Ahmed; Davis, Lora; Nguku, Patrick M; Sani-Gwarzo, Nasir

2016-09-01

In March 2010, Medecins Sans Frontieres/Doctors Without Borders detected an outbreak of acute lead poisoning in Zamfara State, northwestern Nigeria, linked to low-technology gold ore processing. The outbreak killed more than 400 children ≤5 years of age in the first half of 2010 and has left more than 2,000 children with permanent disabilities. The aims of this study were to estimate the statewide prevalence of children ≤5 years old with elevated blood lead levels (BLLs) in gold ore processing and non-ore-processing communities, and to identify factors associated with elevated blood lead levels in children. A representative, population-based study of ore processing and non-ore-processing villages was conducted throughout Zamfara in 2012. Blood samples from children, outdoor soil samples, indoor dust samples, and survey data on ore processing activities and other lead sources were collected from 383 children ≤5 years old in 383 family compounds across 56 villages. 17.2% of compounds reported that at least one member had processed ore in the preceding 12 months (95% confidence intervals (CI): 9.7, 24.7). The prevalence of BLLs ≥10 µg/dL in children ≤5 years old was 38.2% (95% CI: 26.5, 51.4) in compounds with members who processed ore and 22.3% (95% CI: 17.8, 27.7) in compounds where no one processed ore. Ore processing activities were associated with higher lead concentrations in soil, dust, and blood samples. Other factors associated with elevated BLL were a child's age and sex, breastfeeding, drinking water from a piped tap, and exposure to eye cosmetics. Childhood lead poisoning is widespread in Zamfara State in both ore processing and non-ore-processing settings, although it is more prevalent in ore processing areas. Although most children's BLLs were below the recommended level for chelation therapy, environmental remediation and use of safer ore processing practices are needed to prevent further exposures. Obtained. The study protocol was approved by the US Centers for Disease Control Institutional Review Board-A and the National Health Research Ethics Committee of Nigeria. The authors declare no competing financial interests.

Geology and geochemistry of the Reocín zinc-lead deposit, Basque-Cantabrian Basin, Northern Spain

USGS Publications Warehouse

Velasco, Francisco; Herrero, Jose Miguel; Yusta, Inaki; Alonso, Jose Antonio; Seebold, Ignacio; Leach, David

2003-01-01

The Reoci??n Zn-Pb deposit, 30 km southwest of Santander, Spain, occurs within Lower Cretaceous dolomitized Urgonian limestones on the southern flank of the Santillana syncline. The Reoci??n deposit is one of the largest known strata-bound, carbonate-hosted, zinc-lead deposits in Europe. The total metal endowment of the deposit, including past production and remaining reserves, is 62 Mt of ore grading 8.7 percent Zn and 1.0 percent Pb. The epigenetic mineralization consists of sphalerite and galena, with lesser marcasite and trace pyrite with dolomite as gangue. Microprobe analyses of different generations of dolomite revealed nonstoichiometric compositions with various amounts of iron (up to 14 mol % of FeCO3). Replacement of host dolomite, open-space filling of fractures, and cementation of breccias derived from dissolution collapse are the principal types of ore occurrence. Detailed cross-section mapping indicates a stratigraphic and structural control on the deposit. A stratiform morphology is present in the western part of the orebody (Capa Sur), whereas mineralization in the eastern part is highly discordant but strata bound (Barrendera). Stratigraphic studies demonstrate that synsedimentary tectonic activity, related to the rifting of the North Atlantic (Bay of Biscay), was responsible for variation in sedimentation, presence of unconformities (including paleokarsts), local platform emergence and dolomitization along the N60 fault trend. In the Reoci??n area, two stages of dolomitization are recognized. The first stage is a pervasive dolomitization of the limestone country rocks that was controlled by faulting and locally affected the upper part of the Aptian and the complete Albian sequence. The second dolomitization event occurred after erosion and was controlled by karstic cavities. This later dolomitization was accompanied by ore deposition and, locally, filling of dolomite sands and clastic sediments in karstic cavities. The circulation of hydrothermal fluids responsible for sulfide deposition and the infilling of karst cavities were broadly contemporaneous, indicating a post-Albian age. Vitrinite reflectance data are consistent with previously measured fluid inclusion temperatures and indicate temperatures of ore deposition that were less than 100??C. Carbon and oxygen isotopic data from samples of regional limestone, host-rock dolostone and ore-stage dolomite suggest an early hydrothermal alteration of limestone to dolostone. This initial dolomitization was followed by a second period of dolomite formation produced by the mixing of basinal metal-rich fluids with local modified seawater. Both dolomitization events occurred under similar conditions from fluids exhibiting characteristics of basinal brines. The ??34S values of sulfides are between -1.8 and +8.5 per mil, which is consistent with thermochemical sulfate reduction involving organic matter as the main source of reduced sulfur. Galena lead isotope compositions are among the most radiogenic values reported for Zn-Pb occurrences in Europe, and they are distinct from values reported for galena from other Basque-Cantabrian deposits. This suggests that a significant part of the lead was scavenged from the local underlying Asturian sediments. The stratigraphic and structural setting, timing of epigenetic mineralization, mineralogy, and isotopic geochemistry of sulfide and gangue minerals of the Reoci??n deposit are consistent with the features of most of Mississippi Valley-type ore deposits.

Isotopic composition of Pb in ore deposits of the Betic Cordillera, Spain; origin and relationship to other European deposits

USGS Publications Warehouse

Arribas , Antonio; Tosdal, Richard M.

1994-01-01

The Betic Cordillera in southern Spain is a complex Alpine fold belt that resulted from the Cretaceous through Cenozoic collision of Africa with Europe. The region is illustrative of one of the characteristics of the Alpine-Mediterranean orogen: the occurrence over a limited area of mineral deposits with a wide variety of host rocks, mineralization ages, and styles. The metamorphic basement in the Betic zone is characterized by a nappe structure of superimposed tectonostratigraphic units and consists of lower Paleozoic to Lower Triassic clastic metasedimentary rocks. This is overlain by Middle to Upper Triassic platform carbonate rocks with abundant strata-bound F-Pb-Zn-(Ba) deposits (e.g., Sierra de Gador, Sierra Alhamilla). Cretaceous to Paleogene subduction-related compression in southeastern Spain was followed by Miocene postcollisional extension and resulted in the formation of the Almeria-Cartagena volcanic belt and widespread hydrothermal activity and associated polymetallic mineralization. Typical Miocene hydrothermal deposits include volcanic-hosted Au (e.g., Rodalquilar) and Ag-rich base metal (e.g., Cabo de Gata, Mazarron) deposits as well as complex polymetallic veins, mantos, and irregular replacement bodies which are hosted by Paleozoic and Mesozoic metamorphic rocks and Neogene sedimentary and volcanic rocks (e.g., Cartagena, Sierra Almagrera, Sierra del Aguilon, Loma de Bas).Lead isotope compositions were measured on sulfide samples from nine ore districts and from representative fresh samples of volcanic and basement rock types of the region. The results have been used to evaluate ore-forming processes in southeastern Spain with emphasis on the sources of metals. During a Late Triassic mineralizing event, Pb was leached from Paleozoic clastic metasedimentary rocks and incorporated in galena in strata-bound F-Pb-Zn-(Ba) deposits ( 206 Pb/ 204 Pb = 18.332 + or - 12, 207Pb/ 204 Pb = 15.672 + or - 12, 208 Pb/ 204 Pb = 38.523 + or - 46). The second episode of mineralization was essentially contemporaneous (late Miocene) throughout the region and did not involve remobilization of less radiogenic Triassic ore Pb. Lead isotope data indicate a dominantly Paleozoic metasedimentary source for polymetallic vein- and manto-type deposits that formed by hydrothermal circulation through the Betic basement, driven by Miocene intrusions ( 206 Pb/ 204 Pb = 18.747 + or - 20, 207 Pb/ 204Pb = 15.685 + or - 9, 208 /Pb/ 204 Pb = 39.026 + or - 37). Lead in Au-(Cu-Te-Sn) ores is isotopically indistinguishable from that of the calc-alkalic volcanic host ( 206 Pb/ 204 Pb = 18.860 + or - 9, 207 Pb/ 204 Pb = 15.686 + or - 8, 208 Pb/ 204 Pb = 38.940 + or - 27). In contrast, the Pb in volcanic-hosted Pb-Zn-Cu-(Ag-Au) veins was derived from Paleozoic metamorphic and Miocene volcanic rocks ( 206 Pb/ 204 Pb = 18.786 + or - 5, 207 Pb/ 204 Pb = 15.686 + or - 2, 208 Pb/ 204 Pb = 38.967 + or - 9).A comparison of the Pb isotope data from southeastern Spain with published data from selected Pb-Zn deposits in southern Europe (including Les Malines, L'Argentiere, and the Alpine, Iglesiente-Sulcis, and Montagne Noire districts) indicates the importance of a metasedimentary basement as a common source of ore Pb.

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

Carle, S F

Compositional data are represented as vector variables with individual vector components ranging between zero and a positive maximum value representing a constant sum constraint, usually unity (or 100 percent). The earth sciences are flooded with spatial distributions of compositional data, such as concentrations of major ion constituents in natural waters (e.g. mole, mass, or volume fractions), mineral percentages, ore grades, or proportions of mutually exclusive categories (e.g. a water-oil-rock system). While geostatistical techniques have become popular in earth science applications since the 1970s, very little attention has been paid to the unique mathematical properties of geostatistical formulations involving compositional variables.more » The book 'Geostatistical Analysis of Compositional Data' by Vera Pawlowsky-Glahn and Ricardo Olea (Oxford University Press, 2004), unlike any previous book on geostatistics, directly confronts the mathematical difficulties inherent to applying geostatistics to compositional variables. The book righteously justifies itself with prodigious referencing to previous work addressing nonsensical ranges of estimated values and error, spurious correlation, and singular cross-covariance matrices.« less

Igneous layering in the peralkaline intrusions ,Kola Peninsula :leading role of gravitational differentiation

NASA Astrophysics Data System (ADS)

Kogarko, L. N..

2012-04-01

In the center of Kola Peninsula there are two large layered intrusions of agpaitic nepheline syenites - Khibina and Lovozero. . The Khibina alkaline massif (Kola Peninsula,Russia) hosts the world's largest and economically most important apatite deposit. The Khibina massif is a complex multiphase body built up from a number of ring-like and conical intrusions. The apatite bearing intrusion is ring-like and is represented by a layered body of ijolitic composition with a thickness of about 1 - 2 km. The upper zone is represented by different types of apatite ores. These rocks consist of 60-90% euhedral very small (tenths of mm)apatite crystals. The lower zone has mostly ijolitic composition. The lower zone grades into underlying massive urtite consisting of 75-90% large (several mm) euhedral nepheline. Our experimental studies of systems with apatite demonstrated the near-eutectic nature of the apatite-bearing intrusion, resulting in practically simultaneous crystallization of nepheline, apatite and pyroxene. The mathematical model of the formation of the layered apatite-bearing intrusion based on the processes of sedimentation under the conditions of steady state convection taking account of crystal sizes is proposed. Under the conditions of steady-state convection large crystals of nepheline continuously had been settling forming massive underlying urtite whereas smaller crystals of pyroxenes, nepheline and apatite had been stirred in the convecting melt. During the cooling the intensity of convection decreased causing a settling of smaller crystals of nepheline and pyroxene and later very small crystalls of apatite in the upper part of alkaline magma chamber. The Lovozero massif, the largest of the Globe layered peralkaline intrusion, comprises super-large rare-metal (Nb, Ta, REE) deposit. The main ore mineral is loparite (Na, Ce, Ca)2 (Ti, Nb)2O6 which was mined during many years. The composition of cumulus loparite changed systematically upward through the intrusion with an increase in Na, Sr, Nb, Th, Nb/Ta, U/Th and decrease in REE, Zr, V, Zn, Ba and Ti. Our investigation indicates that the formation of loparite ore was the result of several factors including the chemical evolution of highly alkaline magmatic system and mechanical accumulation of loparite at the base of convecting unit.

Cu-As Decoupling in Hydrothermal Systems: A Link Between Pyrite Chemistry and Fluid Composition

NASA Astrophysics Data System (ADS)

Reich, M.; Tardani, D.; Deditius, A.; Chryssoulis, S.; Wrage, J.; Sanchez-Alfaro, P.; Andrea, H.; Cinthia, J.

2016-12-01

Chemical zonations in pyrite have been recognized in most hydrothermal ore deposit types, showing in some cases marked oscillatory alternation of metals and metalloids in pyrite growth zones (e.g., of Cu-rich, As-(Au)-depleted zones and As-(Au)-rich, Cu-depleted zones). This decoupled geochemical behavior of Cu and As has been interpreted as a result of chemical changes in ore-forming fluids, although direct evidence connecting fluctuations in hydrothermal fluid composition with metal partitioning into pyrite growth zones is still lacking. Here we report a comprehensive trace element database of pyrite from an active hydrothermal system, the Tolhuaca Geothermal System (TGS) in southern Chile. We combined high-spatial resolution and X-ray mapping capabilities of electron microprobe analysis (EMPA) with low detection limits and depth-profiling capabilities of secondary-ion mass spectrometry (SIMS) in a suite of pyrite samples retrieved from a 1 km drill hole that crosses the argillic and propylitic alteration zones of the geothermal system. We show that the concentrations of precious metals (e.g., Au, Ag), metalloids (e.g., As, Sb, Se, Te), and base and heavy metals (e.g., Cu, Co, Ni, Pb) in pyrite at the TGS are significant. Among the elements analyzed, arsenic, Cu and Co are the most abundant with concentrations that vary from sub-ppm levels to a few wt. %. Pyrites from the deeper propylitic zone do not show significant zonation and high Cu-(Co)-As concentrations correlate with each other. In contrast, well-developed zonations were detected in pyrite from the shallow argillic alteration zone, where Cu(Co)-rich, As-depleted cores alternate with Cu(Co)-depleted, As-rich rims. These microanalytical data were contrasted with chemical data of fluid inclusion in quartz veins (high Cu/Na and low As/Na) and borehole fluids (low Cu/Na and high As/Na) reported at the TGS, showing a clear correspondence between Cu and As concentrations in pyrite-forming fluids and chemical zonation in pyrite. These observations provide direct evidence supporting the selective partitioning of metals into pyrite as a result of changes in ore-forming fluid composition, most likely due to separation of a single-phase fluid into a low-density vapor and a denser brine, capable to fractionate Cu and As.

Geology and Ore Deposits of the Uncompahgre (Ouray) Mining District, Southwestern Colorado

USGS Publications Warehouse

Burbank, Wilbur Swett; Luedke, Robert G.

2008-01-01

The Uncompahgre mining district, part of the Ouray mining district, includes an area of about 15 square miles (mi2) on the northwestern flank of the San Juan Mountains in southwestern Colorado from which ores of gold, silver, copper, lead, and zinc have had a gross value of $14 to 15 million. Bedrock within the district ranges in age from Proterozoic to Cenozoic. The oldest or basement rocks, the Uncompahgre Formation of Proterozoic age, consist of metamorphic quartzite and slate and are exposed in a small erosional window in the southern part of the district. Overlying those rocks with a profound angular unconformity are Paleozoic marine sedimentary rocks consisting mostly of limestones and dolomites and some shale and sandstone that are assigned to the Elbert Formation and Ouray Limestone, both of Devonian age, and the Leadville Limestone of Mississippian age. These units are, in turn, overlain by rocks of marine transitional to continental origin that are assigned to the Molas and Hermosa Formations of Pennsylvanian age and the Cutler Formation of Permian age; these three formations are composed predominantly of conglomerates, sandstones, and shales that contain interbedded fossiliferous limestones within the lower two-thirds of the sequence. The overlying Mesozoic strata rest also on a pronounced angular unconformity upon the Paleozoic section. This thick Mesozoic section, of which much of the upper part was eroded before the region was covered by rocks of Tertiary age, consists of the Dolores Formation of Triassic age, the Entrada Sandstone, Wanakah Formation, and Morrison Formation all of Jurassic age, and the Dakota Sandstone and Mancos Shale of Cretaceous age. These strata dominantly consist of shales, mudstones, and sandstones and minor limestones, breccias, and conglomerates. In early Tertiary time the region was beveled by erosion and then covered by a thick deposit of volcanic rocks of mid-Tertiary age. These volcanic rocks, assigned to the San Juan Formation, are chiefly tuff breccias of intermediate composition, which were deposited as extensive volcaniclastic aprons around volcanic centers to the east and south of the area. The Ouray area, in general, exhibits the typical effects of a minimum of three major uplifts of the ancestral San Juan Mountains. The earliest of these uplifts, with accompanying deformation and erosion, occurred within the Proterozoic, and the other two occurred at the close, respectively, of the Paleozoic and Mesozoic. The last event, known as the Laramide orogeny, locally was accompanied by extensive intrusion of igneous rocks of dominantly intermediate composition. Domal uplifts of the ancestral mountains resulted in peripheral monoclinal folds, plunging anticlines radial to the central core of the mountain mass, faults, and minor folds. The principal ore deposits of the Uncompahgre district were associated with crosscutting and laccolithic intrusions of porphyritic granodiorite formed during the Laramide (Late Cretaceous to early Tertiary) orogeny. The ores were deposited chiefly in the Paleozoic and Mesozoic sedimentary strata having an aggregate thickness of about 4,500 feet (ft) and occur beneath the early Tertiary unconformity, which in places truncated some of the uppermost deposits. A few ore deposits of late Tertiary age occur also in the sedimentary rocks near the southern margin of the district, but are restricted mostly to the overlying volcanic rocks. Ore deposits in the Uncompahgre district range from low-grade, contact-metamorphic through pyritic base-metal bodies containing silver and gold tellurides and native gold to silver-bearing lead-zinc deposits, and are zoned about the center of intrusive activity, a stock in an area referred to as The Blowout. Ore deposition within the Uncompahgre district was largely controlled by structural trends and axes of uplift established mainly in the late Paleozoic phase of deformation, but also in part by structural lin

Concentrations and forms of heavy metals around two ore processing sites in Katanga, Democratic Republic of Congo

NASA Astrophysics Data System (ADS)

Mees, F.; Masalehdani, M. N. N.; De Putter, T.; D'Hollander, C.; Van Biezen, E.; Mujinya, B. B.; Potdevin, J. L.; Van Ranst, E.

2013-01-01

The concentration of heavy metals and the forms in which they occur were determined for tailings and derived deposits of two major processing sites of Cu-Co and Cu-Zn-(Pb) ores in the Katanga Copperbelt (Kipushi, Likasi). They were studied by a combination of methods, focussed on the nature of water- and EDTA-extractable compounds, the mineralogical composition of tailings and associated secondary minerals, and textural features of metal-bearing efflorescences. For the Kipushi area, sulfide minerals in tailings of decantation basins are identified as the source of extractable metals they contain, but input from an external source rather than local oxidation of substrate components is responsible for high levels of contamination in the Likasi area. Contaminated areas around Likasi are characterized by an abundance of Mg-sulfate efflorescences with high concentrations of cobalt and other metals, acting as an important vector for further dispersion of contaminants by wind and water.

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

USGS Publications Warehouse

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

1981-01-01

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

Face format at encoding affects the other-race effect in face memory.

PubMed

Zhao, Mintao; Hayward, William G; Bülthoff, Isabelle

2014-08-07

Memory of own-race faces is generally better than memory of other-races faces. This other-race effect (ORE) in face memory has been attributed to differences in contact, holistic processing, and motivation to individuate faces. Since most studies demonstrate the ORE with participants learning and recognizing static, single-view faces, it remains unclear whether the ORE can be generalized to different face learning conditions. Using an old/new recognition task, we tested whether face format at encoding modulates the ORE. The results showed a significant ORE when participants learned static, single-view faces (Experiment 1). In contrast, the ORE disappeared when participants learned rigidly moving faces (Experiment 2). Moreover, learning faces displayed from four discrete views produced the same results as learning rigidly moving faces (Experiment 3). Contact with other-race faces was correlated with the magnitude of the ORE. Nonetheless, the absence of the ORE in Experiments 2 and 3 cannot be readily explained by either more frequent contact with other-race faces or stronger motivation to individuate them. These results demonstrate that the ORE is sensitive to face format at encoding, supporting the hypothesis that relative involvement of holistic and featural processing at encoding mediates the ORE observed in face memory. © 2014 ARVO.

FY2017 status report: Model 9975 O-ring fixture long-term leak performance

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

Daugherty, W. L.

A series of experiments to monitor the aging performance of Viton® GLT and GLT-S O-rings used in the Model 9975 shipping package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups with GLT O-rings were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially andmore » have been tested periodically to determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, a smaller test matrix with fourteen additional tests was initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. Leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The 300 °F GLT O-ring fixtures failed after 2.8 to 5.7 years at temperature. The remaining GLT O-ring fixtures aging at 300 ºF were retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 9 to 10.5 years, or in GLT O-ring fixtures aging at 270 ºF for 5.7 years. These aging temperatures bound O-ring temperatures anticipated during normal storage in K-Area Complex (KAC). Leak test failures have been experienced in all of the GLT-S O-ring fixtures aging at 300 ºF and above. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 and 250 ºF for 6.9 to 7.5 years. Data from the O-ring fixtures are generally consistent with results from compression stress relaxation testing, and provide confidence in the predictive models based on those results. However, uncertainty still exists in extrapolating these elevated temperature results to the lower temperatures of interest for normal storage in KAC. Measurement of compression set in O-rings removed from failed fixtures, compared to that from KAC surveillance O-rings, indicates margin remains for O-rings still in service. Aging and periodic leak testing will continue for the remaining PCV fixtures.« less

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

DOEpatents

Maroni, V.A.; von Winbush, S.

1987-05-01

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500/degree/C, electrolysis at a voltage not more negative that about /minus/1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

DOEpatents

Maroni, Victor A.; von Winbush, Samuel

1988-01-01

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500.degree. C., electrolysis at a voltage not more negative than about -1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Mineral and whole-rock compositions of seawater-dominated hydrothermal alteration at the Arctic volcanogenic massive sulfide prospect, Alaska

USGS Publications Warehouse

Schmidt, J.M.

1988-01-01

The Arctic volcanogenic massive sulfide prospect, located in the Ambler mineral district of northwestern Alaska, includes three types of hydrothermally altered rocks overlying, underlying, and interlayered with semimassive sulfide mineralization. Hydrothermal alteration of wall rocks and deposition of sulfide and gangue minerals were contemporaneous with Late Devonian of Early Mississippian basalt-rhyolite volcanism. Alteration developed asymmetrically around a linear fissure, suggesting fracture control of ore fluids rather than a point source. Microprobe analyses of phyllosilicates from the Arctic area indicate two discrete mineral populations. These differences in mineral chemistry are the result of differences in protolith composition caused by hydrothermal alteration-metasomatism. -from Author

Genetic Pd, Pt, Au, Ag, and Rh mineralogy in Noril'sk sulfide ores

NASA Astrophysics Data System (ADS)

Spiridonov, E. M.; Kulagov, E. A.; Serova, A. A.; Kulikova, I. M.; Korotaeva, N. N.; Sereda, E. V.; Tushentsova, I. N.; Belyakov, S. N.; Zhukov, N. N.

2015-09-01

The undeformed ore-bearing intrusions of the Noril'sk ore field (NOF) cut through volcanic rocks of the Late Permian-Early Triassic trap association folded in brachysynclines. Due to the nonuniform load on the roof of intrusive bodies, most sulfide melts were squeezed, up to the tops of ore-bearing intrusions; readily fusible Ni-Fe-Cu sulfide melts were almost completely squeezed. In our opinion, not only one but two stages of mineralization developed at the Noril'sk deposits: (i) syntrap magmatic and (ii) epigenetic post-trap metamorphic-hydrothermal. All platinum-group minerals (PGM) and minerals of gold are metasomatic in the Noril'sk ores. They replaced sulfide solid solutions and exsolution structures. All types of PGM and Au minerals occur in the ores, varying in composition from pyrrhotite to chalcopyrite, talnakhite, mooihoekite, and rich in galena; they are localized in the inner and outer contact zones and differ only in the quantitative proportions of ore minerals. The aureoles of PGM and Au-Ag minerals are wider than the contours of sulfide bodies and coincide with halos of fluid impact on orebodies and adjacent host rocks. The pneumatolytic PGM and Au-Ag minerals are correlated in abundance with the dimensions of sulfide bodies. Their amounts are maximal in veins of late fusible ore composed of eutectic PbS ss and iss intergrowths, as well as at their contacts. The Pd and Pt contents in eutectic sulfide ores of NOF are the world's highest. In the process of noble-metal mineral formation, the fluids supply Pd, Pt, Au, As, Sb, Sn, Bi, and a part of Te, whereas Fe, Ni, Cu, Pb, Ag, Rh, a part of Te and Pd are leached from the replaced sulfide minerals. The pneumatolytic PGM of the early stage comprises Pd and Pt intermetallic compounds enriched in Au along with Pd-Pt-Fe-Ni-Cu-Sn-Pb(As) and (Pd,Pt,Au)(Sn,Sb,Bi,Te,As) solid solutions. Pneumatolytic PGM and Au minerals of the middle stage are products of solid-phase transformation and recrystallization of early PGM in combination with the newly formed mineral species Sb-paolovite-insizwaite-geversite-maslovite, niggliite, tetraferroplatinum, rustenburgite-atokite-zvyagintsevite, moncheite, majakite, plumbopalladinite, polarite in association with altaite. The late minerals of the middle stage include stannopalladinite, tatianaite-taimyrite, Ag-Pd-Pt tetraauricupride, and cuproauride. PGM and Au-Ag minerals of the late stage are represented by sobolevskite-sudburyite-kotulskite, maslovite-michenerite, low-Sb paolovite, hessite, cabriite, Au-Ag minerals with fineness of 870-003, froodite, Sb-free insizwaite, Bi-free geversite, and Sb-free niggliite. Electrum and küstelite in PGM aggregates are not zoned. Crystals of Au-Ag minerals that grow over PGM minerals are smoothly zoned. Their zoning may be direct (crystal margins are enriched in Ag), inverse, oscillatory, and complex. Despite favorable annealing conditions, exsolution structures are not identified in Au-Ag minerals from the Noril'sk ores. Sperrylite—the latest of pneumatolytic PGM—occurs as metacrysts up to 14 cm in size. Sperrylite, which replaces high-Sb minerals, contains up to 11 wt % Sb. Pneumatolytic noble-metal minerals originated under the effect of the fluids released during crystallization of sulfide melts in an extremely reductive setting and at extremely low fS2; temperature drops from ~450 to ~350°C. Metamorphic-hydrothermal Ag mineralization (native silver, Hg-silver, sulfides and selenides, chalcopyrite-lenaite solid solutions, argentopentlandite), Pd mineralization (vysotskite, palladoarsenide, vincentite, Sb-free Ag-paolovite, malyshevite, native palladium), and Pt mineralization (kharaelakhite, cooperite, native platinum) develop in those parts of orebodies that are affected by low-grade metamorphism.

Y-chromosome lineages from Portugal, Madeira and Açores record elements of Sephardim and Berber ancestry.

PubMed

Gonçalves, Rita; Freitas, Ana; Branco, Marta; Rosa, Alexandra; Fernandes, Ana T; Zhivotovsky, Lev A; Underhill, Peter A; Kivisild, Toomas; Brehm, António

2005-07-01

A total of 553 Y-chromosomes were analyzed from mainland Portugal and the North Atlantic Archipelagos of Açores and Madeira, in order to characterize the genetic composition of their male gene pool. A large majority (78-83% of each population) of the male lineages could be classified as belonging to three basic Y chromosomal haplogroups, R1b, J, and E3b. While R1b, accounting for more than half of the lineages in any of the Portuguese sub-populations, is a characteristic marker of many different West European populations, haplogroups J and E3b consist of lineages that are typical of the circum-Mediterranean region or even East Africa. The highly diverse haplogroup E3b in Portuguese likely combines sub-clades of distinct origins. The present composition of the Y chromosomes in Portugal in this haplogroup likely reflects a pre-Arab component shared with North African populations or testifies, at least in part, to the influence of Sephardic Jews. In contrast to the marginally low sub-Saharan African Y chromosome component in Portuguese, such lineages have been detected at a moderately high frequency in our previous survey of mtDNA from the same samples, indicating the presence of sex-related gene flow, most likely mediated by the Atlantic slave trade.

Hydrothermal activity in the Lau back-arc basin: Sulfides and water chemistry

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

Fouquet, Y.; Charlou, J.L.; Donval, J.P.

1991-04-01

The submersible Nautile completed 22 dives during the Nautilau cruise (R/V Nadir, April 17-May 10, 1989) for a detailed investigation of the southern Lau basin near Tonga. The objective of the scientific team from France, Germany, and Tonga was to understand the process of sea-floor ore formation associated with hydrothermal circulation along the Valu Fa back-arc ridge behind the Tonga-Kermadec trench. The four diving areas, between lat21{degree}25'S and 22{degree}40'S in water{approximately}2000 m deep, were selected on the basis of results from cruises of the R/V Jean Charcot and R/V Sonne. The Nadir cruise provided proof of hydrothermal activity-in all formore » areas, over more than 100 km-as indicated by the widespread occurence of hydrothermal deposits and by heat flow, conductivity, and temperature measurements near the sea bottom. The most spectacular findings were high-temperature white and black smokers and associated fauna and ore deposits. Hydrothermal water chemistry and sulfide composition data presented here indicate that this hydrothermal field is very different from the hydrothermal fields in oceanic ridges. This difference is seen in water chemistry of the hydrothermal fluid (pH=2 and high metal content) and the chemical composition of sulfides (enrichment in Ba, As, and Pb).« less

One century sedimentary record of lead and zinc pollution in Yangzong Lake, a highland lake in southwestern China.

PubMed

Zhang, Enlou; Liu, Enfeng; Shen, Ji; Cao, Yanmin; Li, Yanling

2012-01-01

Reconstruction of trace metal pollution histories and sources may help us to regulate current pollutant discharge. This is especially important for the highland lakes in southwestern China, which are facing trace metals pollution. We present sedimentary records of 11 metals accumulated in Yangzong Lake since the 1870's, a highland lake in southwestern China. Pollution of lead and zinc (Pb and Zn) was differentiated based on principal component analysis, geochemical normalization, and lead isotope ratios. Nearly all the metals as well as grain size composition show generally constant values before the mid-1980's, denoting stable detrital input in the catchment. Fluctuations in the concentrations of the metals as well as grain size composition since the mid-1980's indicate an increase in soil erosion with strengthened human disturbance in the catchment. After geochemical normalization, Pb and Zn showed constant values before 1990 AD and then a gradual increase in parallel with the variations in 208Pb/206Pb and 207Pb/206Pb ratios, indicating that Pb and Zn pollution occurred. Combining the data of 208pb/206Pb and 207Pb/6Pb ratios in the sediments of Yangzong Lake, leaded gasoline, Pb-Zn ore and coal, and consumption or production historical trends, we deduced that the enhanced Pb and Zn pollution in Yangzong Lake is caused primarily by ore mining and refining.

Occurrence of silver minerals in a silver-rich pocket in the massive sulfide zinc-lead ores in the Edwards mine, New York

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

Serviss, C.R.; Grout, C.M.; Hagni, R.D.

1985-01-01

Ore microscopic examination of uncommon silver-rich ores from the Edwards mine has detected three silver minerals, native silver, freibergite, and argentite, that were previously unreported in the literature from the Balmat-Edwards district. The zinc-lead ore deposits of the Balmat-Edwards District in northern New York are composed of very coarse-grained massive sulfides, principally sphalerite, galena, and pyrite. The typical ores contain small amounts of silver in solid solution galena. Galena concentrates produced from those ores have contained an average of 15 ounces of silver per ton of 60% lead concentrates. In contrast to the typical ore a silver-rich pocket, that measuredmore » three feet by three feet on the vertical mine face and was the subject of this study, contained nearly 1% silver in a zinc ore. Ore microscopic study shows that this ore is especially characterized by abundant, relatively fine-grained chalcopyrite with anhedral pyrite inclusions. Fine-grained sphalerite, native silver, argentite, freibergite and arsenopyrite occur in association with the chalcopyrite and as fracture-fillings in gangue minerals. Geochemically anomalous amounts of tin, barium, chromium, and nickel also are present in the silver-rich pocket. The silver-rich pocket may mark the locus of an early feeder vent or alternatively it may record a hydrothermal event that was superimposed upon the event responsible for the metamorphic ore textures.« less

29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE ...

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

29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE M. HUMPHREY'S' CARGO OF 25,000. TONS OF ORE. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

Application of indigenous sulfur-oxidizing bacteria from municipal wastewater to selectively bioleach phosphorus from high-phosphorus iron ore: effect of particle size.

PubMed

Shen, Shaobo; Rao, Ruirui; Wang, Jincao

2013-01-01

The effects of ore particle size on selectively bioleaching phosphorus (P) from high-phosphorus iron ore were studied. The average contents of P and Fe in the iron ore were 1.06 and 47.90% (w/w), respectively. The particle sizes of the ores used ranged from 58 to 3350 microm. It was found that the indigenous sulfur-oxidizing bacteria from municipal wastewater could grow well in the slurries of solid high-phosphorus iron ore and municipal wastewater. The minimum bioleaching pH reached for the current work was 0.33. The P content in bioleached iron ore reduced slightly with decreasing particle size, while the removal percentage of Fe decreased appreciably with decreasing particle size. The optimal particle size fraction was 58-75 microm, because the P content in bioleached iron ore reached a minimum of 0.16% (w/w), the removal percentage of P attained a maximum of 86.7%, while the removal percentage of Fe dropped to a minimum of 1.3% and the Fe content in bioleached iron ore was a maximum of 56.4% (w/w) in this case. The iron ores thus obtained were suitable to be used in the iron-making process. The removal percentage of ore solid decreased with decreasing particle size at particle size range of 106-3350 microm. The possible reasons resulting in above phenomena were explored in the current work. It was inferred that the particle sizes of the iron ore used in this work have no significant effect on the viability of the sulfur-oxidizing bacteria.

Multi-Criteria selection of technology for processing ore raw materials

NASA Astrophysics Data System (ADS)

Gorbatova, E. A.; Emelianenko, E. A.; Zaretckii, M. V.

2017-10-01

The development of Computer-Aided Process Planning (CAPP) for the Ore Beneficiation process is considered. The set of parameters to define the quality of the Ore Beneficiation process is identified. The ontological model of CAPP for the Ore Beneficiation process is described. The hybrid choice method of the most appropriate variant of the Ore Beneficiation process based on the Logical Conclusion Rules and the Fuzzy Multi-Criteria Decision Making (MCDM) approach is proposed.

Process for recovering hydrocarbons from a diatomite-type ore

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

Davis, B.W.

1983-02-15

A process for recovering hydrocarbons from a diatomite-type ore which comprises contacting the diatomite ore with a C/sub 4/-C/sub 10/ alcohol and thereafter contacting the diatomite ore-alcohol mixture with an aqueous alkaline solution to separate a hydrocarbon-alcohol phase and an alkaline aqueous phase containing the stripped diatomite ore. Thereafter, the alcohol is distilled off from the hydrocarbon phase and recycled back into the initial process.

6. Looking west showing top of dock: steaming frozen ore ...

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

6. Looking west showing top of dock: steaming frozen ore which had been put in pockets in December 1959, May 6, 1990. Photographer: unknown - Marquette Ore Dock No. 6, Ore Dock, On pilings in Marquette City Lower Harbor, Marquette, Marquette County, MI

Explosion-assisted preparation of dispersed gold-bearing different-grade ore for selective mining

NASA Astrophysics Data System (ADS)

Trubachev, AI; Zykov, NV

2017-02-01

It is found that there are transient zones (between quality and off-quality ore areas) with the respective content of useful component in an ore body, and a variant of explosive treatment of such zones before the selective mining is put forward. Practicability of two processing technologies is evaluated: processing of high-grade and low-grade ore from the transient zones and heap leaching of metals from the low-grade and impoverished ore. Open mining technology is conventional truck-and-shovel scheme, with distributed ore flows to processing plant and (or) to heap leaching, which generally enhances the mine efficiency.

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

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Prevalence and Risk Factors of Elevated Blood Lead in Children in Gold Ore Processing Communities, Zamfara, Nigeria, 2012

PubMed Central

Kaufman, John A.; Brown, Mary Jean; Umar-Tsafe, Nasir T.; Adbullahi, Muhammad Bashir; Getso, Kabiru I.; Kaita, Ibrahim M.; Sule, Binta Bako; Ba’aba, Ahmed; Davis, Lora; Nguku, Patrick M.; Sani-Gwarzo, Nasir

2018-01-01

Background In March 2010, Medecins Sans Frontieres/Doctors Without Borders detected an outbreak of acute lead poisoning in Zamfara State, northwestern Nigeria, linked to low-technology gold ore processing. The outbreak killed more than 400 children ≤5 years of age in the first half of 2010 and has left more than 2,000 children with permanent disabilities. Objectives The aims of this study were to estimate the statewide prevalence of children ≤5 years old with elevated blood lead levels (BLLs) in gold ore processing and non-ore-processing communities, and to identify factors associated with elevated blood lead levels in children. Methods A representative, population-based study of ore processing and non-ore-processing villages was conducted throughout Zamfara in 2012. Blood samples from children, outdoor soil samples, indoor dust samples, and survey data on ore processing activities and other lead sources were collected from 383 children ≤5 years old in 383 family compounds across 56 villages. Results 17.2% of compounds reported that at least one member had processed ore in the preceding 12 months (95% confidence intervals (CI): 9.7, 24.7). The prevalence of BLLs ≥10 µg/dL in children ≤5 years old was 38.2% (95% CI: 26.5, 51.4) in compounds with members who processed ore and 22.3% (95% CI: 17.8, 27.7) in compounds where no one processed ore. Ore processing activities were associated with higher lead concentrations in soil, dust, and blood samples. Other factors associated with elevated BLL were a child’s age and sex, breastfeeding, drinking water from a piped tap, and exposure to eye cosmetics. Conclusions Childhood lead poisoning is widespread in Zamfara State in both ore processing and non-ore-processing settings, although it is more prevalent in ore processing areas. Although most children’s BLLs were below the recommended level for chelation therapy, environmental remediation and use of safer ore processing practices are needed to prevent further exposures. Patient consent Obtained Ethics approval The study protocol was approved by the US Centers for Disease Control Institutional Review Board-A and the National Health Research Ethics Committee of Nigeria. Competing Interests The authors declare no competing financial interests. PMID:29416933

Geology and ore fluid geochemistry of the Jinduicheng porphyry molybdenum deposit, East Qinling, China

NASA Astrophysics Data System (ADS)

Li, Hongying; Ye, Huishou; Wang, Xiaoxia; Yang, Lei; Wang, Xiuyuan

2014-01-01

Jinduicheng deposit is a giant Mesozoic porphyry Mo system deposit in the East Qinling molybdenum belt, Shaanxi Province, China. The mineralization is associated with the I-type Jinduicheng granite porphyry. Both the porphyry stock and country rocks underwent intense hydrothermal alteration. The alteration, with increasing distance from the parent intrusion, changes from silicification, through potassic and phyllic assemblages, carbonation, to propylitic assemblages. Molybdenite, the dominant ore mineral, occurs in veinlets, most of which are hosted by the altered country rocks, with less than 25% of the ore in the porphyry body. The hydrothermal system comprises four stages, including pre-ore quartz and K-feldspar; two ore stages of quartz, K-feldspar, molybdenite, and Pb- And Zn-bearing sulfides; and post-ore quartz and carbonate. Six main types of primary fluid inclusions are present in hydrothermal quartz, including two-phase aqueous, one-phase aqueous, three-phase CO2-bearing, CO2-dominated fluid inclusions, gas inclusions, and melt inclusions. The homogenization temperatures of fluid inclusions range from 210 to 290 °C in the pre-ore stage, 150-310 °C in ore stage I, 150-360 °C in the ore stage II, and 195-325 °C in the post-ore stage quartz. Estimated salinities of the ore-forming fluids range from 6.9 to 13.5, 4.3 to 12.3, 6.2 to 12.4, and 3.4 to 9.9 wt.% NaCl equiv. in stages 1-4, respectively. The δ34S values of pyrite in the two ore stages range from 2.8‰ to 4.3‰, whereas the δ34S values of molybdenite range from 2.9‰ to 6.2‰. The data suggest both magmatic and crustal sources of sulfur. The δD and δ18O values for the hydrothermal fluids are -57.2‰ to -84.4‰ and 8.0‰ to -3.2‰, respectively. The fluid inclusion and stable data indicate that the pre-ore hydrothermal fluids were mostly of magmatic origin, but the fluids responsible for ore deposition were mixed magmatic and meteoric, and eventually meteoric water dominated the system in the post-ore stage.

Specific composition of native silver from the Rogovik Au-Ag deposit, Northeastern Russia

NASA Astrophysics Data System (ADS)

Kravtsova, R. G.; Tauson, V. L.; Palyanova, G. A.; Makshakov, A. S.; Pavlova, L. A.

2017-09-01

The first data on native silver from the Rogovik Au-Ag deposit in northeastern Russia are presented. The deposit is situated in central part of the Okhotsk-Chukchi Volcanic Belt (OCVB) in the territory of the Omsukchan Trough, unique in its silver resources. Native silver in the studied ore makes up finely dispersed inclusions no larger than 50 μm in size, which are hosted in quartz; fills microfractures and interstices in association with küstelite, electrum, acanthite, silver sulfosalts and selenides, argyrodite, and pyrite. It has been shown that the chemical composition of native silver, along with its typomorphic features, is a stable indication of the various stages of deposit formation and types of mineralization: gold-silver (Au-Ag), silver-base metal (Ag-Pb), and gold-silver-base metal (Au-Ag-Pb). The specificity of native silver is expressed in the amount of trace elements and their concentrations. In Au-Ag ore, the following trace elements have been established in native silver (wt %): up to 2.72 S, up to 1.86 Au, up to 1.70 Hg, up to 1.75 Sb, and up to 1.01 Se. Native silver in Ag-Pb ore is characterized by the absence of Au, high Hg concentrations (up to 12.62 wt %), and an increase in Sb, Se, and S contents; the appearance of Te, Cu, Zn, and Fe is notable. All previously established trace elements—Hg, Au, Sb, Se, Te, Cu, Zn, Fe, and S—are contained in native silver of Au-Ag-Pb ore. In addition, Pb appears, and silver and gold amalgams are widespread, as well as up to 24.61 wt % Hg and 11.02 wt % Au. Comparison of trace element concentrations in native silver at the Rogovik deposit with the literature data, based on their solubility in solid silver, shows that the content of chalcogenides (S, Se, Te) exceeds saturated concentrations. Possible mechanisms by which elevated concentrations of these elements are achieved in native silver are discussed. It is suggested that the appearance of silver amalgams, which is unusual for Au-Ag mineralization not only in the Omsukchan Trough, but also in OCVB as a whole, is caused by superposition of the younger Dogda-Erikit Hg-bearing belt on the older Ag-bearing Omsukchan Trough. In practice, the results can be used to determine the general line of prospecting and geological exploration at objects of this type.

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the...

28 CFR 79.62 - Criteria for eligibility for claims by ore transporters.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ore transporters. 79.62 Section 79.62 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Ore Transporters § 79.62 Criteria for eligibility for claims by ore transporters. To establish eligibility for compensation...

28 CFR 79.62 - Criteria for eligibility for claims by ore transporters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ore transporters. 79.62 Section 79.62 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Ore Transporters § 79.62 Criteria for eligibility for claims by ore transporters. To establish eligibility for compensation...

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the...

28 CFR 79.62 - Criteria for eligibility for claims by ore transporters.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ore transporters. 79.62 Section 79.62 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Ore Transporters § 79.62 Criteria for eligibility for claims by ore transporters. To establish eligibility for compensation...

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vanadium ore subcategory. 440.80 Section 440.80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a Byproduct) § 440.80 Applicability; description of the...

28 CFR 79.62 - Criteria for eligibility for claims by ore transporters.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ore transporters. 79.62 Section 79.62 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Ore Transporters § 79.62 Criteria for eligibility for claims by ore transporters. To establish eligibility for compensation...

Translations on Eastern Europe, Scientific Affairs, Number 543

DTIC Science & Technology

1977-04-29

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

32. INTERIOR VIEW LOOKING NORTH ON THE ORE BREAKER LEVEL. ...

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

32. INTERIOR VIEW LOOKING NORTH ON THE ORE BREAKER LEVEL. THE ORE BREAKER, A BLAKE JAW CRUSHER, IS IN THE BOX IN THE LEFT OF THE PHOTOGRAPH, THE ORE TO BE BROKEN IS FED INTO THE OPENING ON THE FLOOR AND NEXT TO ORE BREAKER BOX. THE GRIZZLY BARS ARE ON THE RIGHT AND THE PULLEYS FROM THE POWER SYSTEM ARE OVERHEAD. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

Acid pre-treatment method for in situ ore leaching

DOEpatents

Mallon, R.G.; Braun, R.L.

1975-10-28

An acid leaching method is described for the recovery of a desired element from a subterranean rubblized body of primary ore containing the element and also having associated therewith a carbonate mineral wherein the rubblized ore body is flooded with an aqueous acidic solution in order to release carbon dioxide from the associated carbonate mineral. After a substantial portion of the available carbon dioxide is released and removed from the ore body, as by venting to the atmosphere, an oxidizing gas is introduced into the flooded, rubblized ore to oxidize the ore and form an acid leach solution effective in the presence of the dissolved oxidizing gas to dissolve the ore and cause the desired element to go into solution. The leach solution is then circulated to the surface where the metal values are recovered therefrom.

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

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

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2014 CFR

2014-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2012 CFR

2012-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2013 CFR

2013-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

17. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN ...

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

17. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN BUILT IN 1911-1912, THIS WAS THE LARGEST ORE-UNLOADING DOCK ON THE GREAT LAKES. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

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

Code of Federal Regulations, 2010 CFR

2010-07-01

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

Geochemical Modeling of Zinc Silicate Ore Formation from Sedimentary Hydrothermal Fluids

NASA Astrophysics Data System (ADS)

Appold, M. S.

2008-12-01

Sediment-hosted zinc deposits dominated by willemite (Zn2SiO4) instead of sphalerite (ZnS) are known from several prominent occurrences worldwide, including Vazante, Brazil, the Aroona Trend, Australia, Kabwe, Zambia, Berg Aukas, Namibia, and Abu Samar, Sudan. Although willemite-dominant zinc deposits appear to be much less common and are on average smaller than sphalerite-dominant zinc deposits, they nonetheless represent major enrichments of zinc in the Earth's crust, reaching sizes on the order of 1's to 10's of millions of tons and grades commonly between 20 and 40%. Sediment-hosted willemite- and sphalerite-dominant deposits share many similarities including their predominantly carbonate host rocks, gangue mineralogy, presumed derivation from sedimentary basinal brines, and spatial proximity. However, the conditions and processes that led to one style of mineralization versus the other have only recently begun to be investigated. The current study presents solubility, reaction path, and reactive transport modeling results that attempt to define more clearly the conditions that favor willemite ore formation in sedimentary basins, with a focus on the Vazante deposit. Solubility calculations for willemite and sphalerite as a function of temperature, pH, salinity, and oxidation potential were carried out using a simple 3 molal NaCl solution saturated with respect to quartz. The results show that (1) willemite solubility is relatively insensitive to changes in temperature and oxidation potential whereas sphalerite solubility decreases sharply with decreasing temperature and oxidation potential, (2) willemite solubility decreases more strongly than sphalerite with increasing pH, (3) willemite and sphalerite have a similar strong decrease in solubility with decreasing salinity. The results support a previously proposed genetic model for a willemite-dominant, sphalerite-subordinate ore body like Vazante in which a hot, acidic, metal-rich ore fluid mixed with a cooler, more oxidizing, dilute, and basic fluid. This scenario was investigated further with reaction path and reactive transport modeling. In these models, a more complex ore fluid was used that was assumed to have a major element composition similar to the global average for Mississippi Valley-type (MVT) deposits determined from the literature, modified by heating from 150 to 300° C, saturated with respect to dolomite and quartz, moderately acidic, and an oxidation potential near the value defined by magnetite-hematite equilibrium. The ore fluid was allowed to mix with a second, possibly meteoric fluid with about three orders of magnitude lower salinity, neutral pH, and a temperature of 50° C. The modeling results showed general agreement with the mineral assemblage observed at Vazante, and confirmed the need for a strong pH increase to induce willemite precipitation, and no more than a moderate increase in oxidation potential to allow some sphalerite to precipitate. The localization of mineralization within a shear zone was found to depend strongly on the shear zone having acted as a high permeability conduit for the ore fluid from deeper parts of the sedimentary basin.

Impact of nickel mining in New Caledonia assessed by compositional data analysis of lichens.

PubMed

Pasquet, Camille; Le Monier, Pauline; Monna, Fabrice; Durlet, Christophe; Brigaud, Benjamin; Losno, Rémi; Chateau, Carmela; Laporte-Magoni, Christine; Gunkel-Grillon, Peggy

2016-01-01

The aim of this study is to explore the use of lichens as biomonitors of the impact of nickel mining and ore treatment on the atmosphere in the New Caledonian archipelago (South Pacific Ocean); both activities emitting also Co, Cr and possibly Fe. Metal contents were analysed in thirty-four epiphytic lichens, collected in the vicinity of the potential sources, and in places free from known historical mining. The highest Ni, Co, and Cr concentrations were, as expected, observed in lichens collected near ore deposits or treatment areas. The elemental composition in the lichens was explored by multivariate analysis, after appropriately transforming the variables (i.e. using compositional data analysis). The sample score of the first principal component (PC1) makes the largest (positive) multiplicative contribution to the log-ratios of metals originating from mining activities (Ni, Cr, Co) divided by Ti. The PC1 scores are used here as a surrogate of pollution levels related to mining and metallurgical activity. They can be viewed as synthetic indicators mapped to provide valuable information for the management and protection of ecosystems or, as a first step, to select locations where air filtration units could be installed, in the future, for air quality monitoring. However, as this approach drastically simplifies the problem, supplying a broadly efficient picture but little detail, recognizing the different sources of contamination may be difficult, more particularly when their chemical differences are subtle. It conveys only relative information: about ratios, not levels, and is therefore recommended as a preliminary step, in combination with close examination of raw concentration levels of lichens. Further validation using conventional air-monitoring by filter units should also prove beneficial.

Applications of the 190Pt-186Os isotope system to geochemistry and cosmochemistry

USGS Publications Warehouse

Walker, R.J.; Morgan, J.W.; Beary, E.S.; Smoliar, M.I.; Czamanske, G.K.; Horan, M.F.

1997-01-01

Platinum is fractionated from osmium primarily as a consequence of processes involving sulfide and metal crystallization. Consequently, the 190Pt-186Os isotope system (190Pt ??? 186Os + ??) shows promise for dating some types of magmatic sulfide ores and evolved iron meteorites. The first 190Pt-186Os isochrons are presented here for ores from the ca. 251 Ma Noril'sk, Siberia plume, and for group IIAB magmatic iron meteorites. Given the known age of the Noril'sk system, a decay constant for 190Pt is determined to be 1.542 ?? 10-12a-1, with ??1% uncertainty. The isochron generated for the IIAB irons is consistent with this decay constant and the known age of the group. The 186Os/188Os ratios of presumably young, mantle-derived osmiridiums and also the carbonaceous chondrite Allende were measured to high-precision to constrain the composition of the modern upper mantle. These compositions overlap, indicating that the upper mantle is chondritic within the level of resolution now available. Our best estimate for this 186Os/188Os ratio is 0.119834 ?? 2 (2??M). The 190Pt/186Os ratios determined for six enstatite chondrites average 0.001659 ?? 75, which is very similar to published values for carbonaceous chondrites. Using this ratio and the presumed composition of the modern upper mantle and chondrites, a solar system initial 186Os/188Os ratio of 0.119820 is calculated. In comparison to the modern upper mantle composition, the 186Os/188Os ratio of the Noril'sk plume was approximately 0.012% enriched in 186Os. Possible reasons for this heterogeneity include the recycling of Pt-rich crust into the mantle source of the plume and derivation of the osmium from the outer core. Derivation of the osmium from the outer core is our favored model. Copyright ?? 1997 Elsevier Science Ltd.

Mg-enriched erythrite from Bou Azzer, Anti-Atlas Mountains, Morocco: geochemical and spectroscopic characteristics

NASA Astrophysics Data System (ADS)

Dumańska-Słowik, Magdalena; Pieczka, Adam; Natkaniec-Nowak, Lucyna; Kunecki, Piotr; Gaweł, Adam; Heflik, Wiesław; Smoliński, Wojciech; Kozub-Budzyń, Gabriela

2018-06-01

Supergene Mg-enriched erythrite, with an average composition (Co2.25Mg0.58Ni0.14Fe0.04Mn0.02 Zn0.02) (As1.97P<0.01O8)·8H2O, accompanied by skutterudite, roselite and alloclasite, was identified in a pneumo-hydrothermal quartz-feldspar-carbonate matrix within the ophiolite sequence of Bou Azzer in Morocco. The unit cell parameters of monoclinic Mg-enriched erythrite [space group C2/ m, a = 10.252(2) Å, b = 13.427(3) Å, c = 4.757(3) Å, ß = 105.12(1)°] make the mineral comparable with erythrite from other localities. The composition of the sample represents the solid solution between erythrite, hörnesite and annabergite, that is, the nearest to the endmember erythrite. However, Mg-enriched erythrite forming the crystal exhibits variable compositions, especially in Mg and Co contents, with Mg increasing from 0.32 up to 1.39 apfu, and Co decreasing from 2.53 to 1.50 apfu, which manifests in the fine compositional oscillatory zoning. It is the highest content of Mg in erythrite structure reported so far. The most intensive Raman active ν3 and ν1 bands, recorded for the crystal's zones with maximum Mg contents, occur at 865 and 800 cm- 1 and are shifted towards higher wavenumbers, where normally hörnesite Raman bands appear. The characteristic oscillatory zoning texture results from varying contents of main and trace elements mobilized from the host ores (Co arsenides, mainly skutterudite) and rock-forming minerals (among others, dolomite) by the solutions in the oxidation zone of the ore deposits. The heating of the Mg-enriched erythrite up to 1000 °C leads to the crystallization of the water-free (Co,Mg)3(AsO4)2 phase.

Enhancement of gold recovery using bioleaching from gold concentrate

NASA Astrophysics Data System (ADS)

Choi, S. H.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

2012-04-01

The gold in refractory ores is encapsulated as fine particles (sometimes at a molecular level) in the crystal structure of the sulfide (typically pyrite with or without arsenopyrite) matrix. This makes it impossible to extract a significant amount of refractory gold by cyanidation since the cyanide solution cannot penetrate the pyrite/arsenopyrite crystals and dissolve gold particles, even after fine grinding. To effectively extract gold from these ores, an oxidative pretreatment is necessary to break down the sulfide matrix. The most popular methods of pretreatment include nitric acid oxidation, roasting, pressure oxidation and biological oxidation by microorganisms. This study investigated the bioleaching efficiency of Au concentrate under batch experimental conditions (adaptation cycles and chemical composition adaptation) using the indigenous acidophilic bacteria collected from gold mine leachate in Sunsin gold mine, Korea. We conducted the batch experiments at two different chemical composition (CuSO4 and ZnSO4), two different adaptation cycles 1'st (3 weeks) and 2'nd (6 weeks). The results showed that the pH in the bacteria inoculating sample decreased than initial condition and Eh increased. In the chemical composition adaptation case, the leached accumulation content of Fe and Pb was exhibited in CuSO4 adaptation bacteria sample more than in ZnSO4 adaptation bacteria samples, possibly due to pre-adaptation effect on chalcopyrite (CuFeS2) in gold concentrate. And after 21 days on the CuSO4 adaptation cycles case, content of Fe and Pb was appeared at 1'st adaptation bacteria sample(Fe - 1.82 and Pb - 25.81 times per control sample) lower than at 2'nd adaptation bacteria sample(Fe - 2.87 and Pb - 62.05 times per control sample). This study indicates that adaptation chemical composition and adaptation cycles can play an important role in bioleaching of gold concentrate in eco-/economic metallurgy process.

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

USGS Publications Warehouse

Carr, Martha S.; Dutton, Carl E.

1959-01-01

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

The recovery of gold from refractory ores by the use of carbon-in-chlorine leaching

NASA Astrophysics Data System (ADS)

Greaves, John N.; Palmer, Glenn R.; White, William W.

1990-09-01

Recently, the U.S. Bureau of Mines examined the recovery of gold by chlorination of refractory carbonaceous and sulfidic ores, comparing various treatment methods in which a ground ore pulp is contacted with chlorine gas and activated carbon is added to the pulp for a carbon-in-chlorine leach (CICL). The objective of this research was to demonstrate the basic feasibility of CICL technology. Results showed that the organic carbon deactivating environment of CICL lowers, but does not eliminate, the adsorption of gold on activated carbon. In this environment, the refractory ore is altered, and gold is extracted and then recovered on activated carbon. With highly carbonaceous ores, CICL achieved a higher recovery than with primarily sulfidic refractory ores. Basic cyanide amenability testing of two carbonaceous ores achieved recoveries of only 5.5% and 46%. With CICL treatment, recoveries on carbon were 90% and 92%.

The Darzi-Vali bauxite deposit, West-Azarbaidjan Province, Iran: Critical metals distribution and parental affinities

NASA Astrophysics Data System (ADS)

Khosravi, Maryam; Abedini, Ali; Alipour, Samad; Mongelli, Giovanni

2017-05-01

The Darzi-Vali bauxite deposit, located 20 km east of Bukan, in northwestern Iran, occurs as discontinuous layers and lenses within the Upper Permian carbonate rocks of the Ruteh Formation. These layers extend laterally for over ∼1 km and vary in thickness ranging from 2 to 17 m. We studied the chemical variations in a selected stratigraphic section throughout the deposit, focusing in particular on numbers of selected special metals that make the deposit of potential economic importance. The critical elements Co, Ga, Nb, Ta, LREEs, and HREEs, along with transition metal Ni, are variously depleted throughout the deposit with respect to Ti, which is assumed to be a less mobile element. Among the critical elements, Cr has only demonstrated conservative behavior. Factor analysis suggests that the factors controlling the distribution of LREEs and HREEs in the ore, which most likely depend on the local composition of groundwater during weathering, are different from those controlling the distribution of other critical elements. Further, the Darzi-Vali ore has ΣREE contents (773 ppm) much higher with respect to other deposits located in NW of Iran, making this deposit worthy of further investigations. As for parental affinity, the Eu anomalies show negligible fluctuations (0.82-0.94) all along the deposit confirming that bauxitization does not affect the effectiveness of this provenance proxy. The average Eu/Eu* value (0.89) of the ore is relatively far afield from that of the average carbonate bedrock (1.3) and close to that of the average mafic protolith (0.94), and similar results are also obtained using the Sm/Nd and Tb/Tb* proxies. Bivariate plots of Eu anomaly versus Sm/Nd and Tb anomalies further support the idea that mafic rocks are probably related to the volcanic activities. These volcanic activities affected the Iranian platform during the Upper Permian as proposed for other bauxite deposits in northwestern Iran. These mafic rocks were the probable precursor of the Darzi-Vali bauxite ore.

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

DOE PAGES

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

2017-10-20

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

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

NASA Astrophysics Data System (ADS)

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

2018-05-01

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

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

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

Balboni, Enrica; Spano, T; Cook, N

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

Thermal analysis of calcium sulfate dihydrate sources used to manufacture gypsum wallboard

DOE PAGES

Engbrecht, Dick C.; Hirschfeld, Deidre A.

2016-07-27

Gypsum wallboard has been used for over 100 years as a barrier to the spread of fire in residential and commercial structures. The gypsum molecule, CaSO 4·2H 2O, provides two crystalline waters that are released upon heating providing an endothermic effect. Manufacturers have recognized that the source of the gypsum ore is a factor that affects all aspects of its performance; thus, it is hypothesized that the impurities present in the gypsum ore are the causes of the performance differences. Differential Thermal Analysis/Thermogravimetric Analysis (DTA/TGA) and X-ray Diffraction (XRD) were used in this paper to compare and characterize samples ofmore » gypsum ore representing sources of natural, synthetic from a Flue Gas Desulfurization process (FGD) and blends thereof. The hemihydrate phase of representative natural, FGD, and reagent grade calcium sulfate were rehydrated with distilled water and evaluated by DTA/TGA. Analysis of the data shows distinct areas of similarity separated by the conversion to anhydrite ~250 °C. Compositional reconstructions based on DTA/TGA and XRD data were compared and although, the results were comparable, the DTA/TGA suggests thermally active compounds that were not detected by XRD. Anhydrite, silica and halite were reported by XRD but were not thermally reactive in the temperature range evaluated by DTA/TGA (ambient to 1050 °C). Finally, the presence of carbonate compounds (e.g., calcite and dolomite) were indicated by XRD and estimated from the thermal decomposition reaction ~700 °C.« less

Fuel and Fuel System Materials Compatibility Test Program for A JP-8+100 Fuel Additive. Volume 1: Thermal Stability Additive Package BetzDearborn Spec Aid(Registered) 8Q462

DTIC Science & Technology

2001-10-01

SAE Rings, Sealing, Butadiene-Acrylonitrile ( NBR ), Rubber Fuel and Low Temperature Resistant 60 - 70 MIL-R-83248C Rubber , Fluorocarbon...KAPTON/TEFLON (COMPOSITE) WIRE I.I.10 34 VI. REFERENCE DOCUMENTS Non-Metallics MIL-HDBK-149B Military Standardization Hand Book Rubber ...ASTM D-1414 Standard Test Methods for Rubber O-Rings ASTM D-412 Type II Standard Test Methods for Vulcanized Rubber and Thermoplastic

Measurement of the Out-of-Plane Shear Response of Thick Section Composite Materials Using the V-Notched Beam Specimen

DTIC Science & Technology

1993-04-01

to failure at 1.25 mm/min.(.05 in./min.) by a hydraulic, 267 kN (60,000 lb.) capacity, Satec testing machine. Strain output was conditioned through...D.Hoyns 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS( ES ) ’S. PERFORMING ORGANIZATION REPORT NUMBER Naval Surface Warfare Center Carderock Division...Annapolis Detachment CRDKNSWC-SSM-64-92/22 Code 2844/644 9. SPONSORING /MON7ORING AGENCY NAME(S) AND ADDRESS( ES ) 10. SPONSORING /MONITOR INGAGENCY REPORT

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE ...

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

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE CARS TOWARDS WESTERN SIDE OF CLEVELAND BULK TERMINAL BUILDINGS AND A SELF-UNLOADING IRON ORE SHIP AT DOCK. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

Tracing of ca 800 yr old mining activity in peat bog using Pb elemental concentrations and isotope compositions.

NASA Astrophysics Data System (ADS)

Baron, S.; Carignan, J.; Ploquin, A.

2003-04-01

Sixty sites of slags have been documented on the Mont-Lozère in southern France. The petrographic analysis shows that slags are metallurgical wastes (800 to 850 yr BP) which certainly result from smelting activity for lead and silver extraction (Ploquin et al., 2001). The aims of this study are: 1) to trace the source of Pb ores which supplied the smelting sites, by using the Pb isotopic composition of several surrounding Pb deposits, 2) to evaluate the actual pollution caused by these slags, by using elemental and isotopic compositions of soils, water and vegetation, and 3) to document the pollution history of the region, by using elemental and isotopic compositions of peat bog cores collected in the neighbourhood of the historical smelting sites. The lead isotopic composition of galena collected in most surrounding ores is very similar to that of different slag samples. On the other hand, the high precision of the results allowed us to select the mineralised areas which were probably the ore sources. The Pb isotopic composition of slags is even more homogeneous: 208/206 Pb: 2.092±0.002; 206/207 Pb: 1.179±0.001; 208/204 Pb: 38.663±0.025; 207/204 Pb: 15.665±0.006; 206/204 Pb: 18.476±0.023, and will allow source tracing in the environment. The "Narses Mortes" peat bog, around which two smelting sites have been reported, is strongly minerotrophic and contains 8 to 60% ash. A 1.40 m core have been retrieved and divided into 58 individual samples. Minerotrophic peat bog records both atmospheric deposition, soils leaching and the grounwater influence. The measured metal concentrations are normalised to Al contents of peat bog samples and the metal/Al ratios are compared to that of the Mont-Lozère granite: relative excess in metal concentrations are found in peat bog samples. An increasing excess of most metals (Pb, Zn, Cd...) was measured for surface samples, from 55 cm depth to the top of the core (23 cm depth). This profil might be attributed to atmospheric input during the last centuries. Pb and As alone are also enriched in some deeper samples (between 120--90 cm depth). At the moment, no sedimentation rates are available for this section of the peat bog. However, according to palynological data (de Beaulieu, in progress), the bottom of the core might be as old as 5000 years BP. This would place the medieval activities at the base of the surface metal enrichment (˜55 cm depth), having no large effect in Pb concentrations measured in peat bog. The older Pb-As enrichment remain enigmatic and may correspond to earlier anthropogenic activities (2000--2500 BP), a period for which very few traces of metallurgical activities are found in Occidental Europe. 14C dating and Pb isotope works are going on peat bog samples trying to discriminate metals sources.

Radon emanation from low-grade uranium ore.

PubMed

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

2013-12-01

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

Using apatite to discriminate synchronous ore-associated and barren granitoid rocks: A case study from the Edong metallogenic district, South China

NASA Astrophysics Data System (ADS)

Duan, Deng-Fei; Jiang, Shao-Yong

2018-06-01

In order to find criteria to discriminate the synchronous ore-associated and barren granitoid rocks, we have determined apatite chemistry associated with ore-associated (Cu-Au) and barren granitoid rocks in the Edong district of the Middle and Lower Yangtze River metallogenic belt, South China. Both rock types give zircon U-Pb ages between 135.0 and 138.7 Ma. Apatite has a higher volatile and Li content (Cl: 0.19-0.57 wt%, average 0.35 wt%, SO3: 0.08-0.71 wt%, average 0.32 wt%, Li: 0.49-7.99 ppm, average 3.23 ppm) in ore-associated rocks than those in barren rocks (Cl: 0.09-0.31 wt%, average 0.16 wt%, SO3: 0.06-0.28 wt%, average 0.16 wt%, Li: 0.15-0.89 ppm, average 0.36 ppm). Apatite (La/Yb)N ratios and Eu/Eu* values are relatively high and show wider variation in ore-associated rocks than those in barren rocks. Apatite (La/Sm)N and (Yb/Sm)N show positive correlation in ore-associated rocks but negative in barren rocks. The higher volatile content occurs in ore-associated magma, favoring Cu-Au transportation and deposition. Furthermore, amphibole fractional crystallization in ore-associated magma further enriched the ore elements in the residual melt. Barren rocks may have undergone fluid exsolution before emplacement, which makes it barren in Cl, S and ore elements (Cu, S). These signatures emphases the significance of volatile and magma evolution in mineralization and indicate that analyses of magmatic apatite can serve to distinguish ore-associated from barren intrusions.

Gold ores related to shear zones, West Santa Comba-Fervenza Area (Galicia, NW Spain): A mineralogical study

NASA Astrophysics Data System (ADS)

Castroviejo, R.

1990-12-01

Recent research has discovered high-grade Au ores in NNE-SSW trending shear zones in metamorphic proterozoic and palaeozoic terranes, some 40 km NW of Santiago de Compostela (NW Spain). The orebodies are bound to late-stage Hercynian structures, mainly due to brittle deformation, which are superimposed on earlier ductile shear zones, cutting through various catazonal lithologies, including ortho- and paragneisses, amphibolites, eclogites, and granites. Ore mineralogy, alteration, and ore textures define a frame whose main features are common to all prospects in the area. Main minerals are arsenopyrite and pyrite — accompanied by quartz, adularia, sericite, ± (tourmaline, chlorite, carbonates, graphite), as main gangue minerals -with subordinate amounts of boulangerite, bismuthinite, kobellite, jamesonite, chalcopyrite, marcasite, galena, sphalerite, rutile, titanite, scheelite, beryl, fluorite, and minor native gold, electrum, native bismuth, fahlore, pyrrhotite, mackinawite, etc., defining a meso-catathermal paragenesis. Detailed microscopic study allows the author to propose a general descriptive scheme of textural classification for this type of ore. Most of the ores fill open spaces or veins, seal cracks or cement breccias; disseminated ores with replacement features related to alteration (mainly silicification, sericitization, and adularization) are also observed. Intensive and repeated cataclasis is a common feature of many ores, suggesting successive events of brittle deformation, hydrothermal flow, and ore precipitation. Gold may be transported and accumulated in any of these events, but tends to be concentrated in later ones. The origin of the gold ores is explained in terms of hydrothermal discharge, associated with mainly brittle deformation and possibly related to granitic magmas, in the global tectonic frame of crustal evolution of West Galicia. The mineralogical and textural study suggests some criteria which will be of practical value for exploration and for ore processing. Ore grades can be improved by flotation of arsenopyrite. Non-conventional methods, such as pressure or bacterial leaching, may subsequently obtain a residue enriched in gold.

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

USGS Publications Warehouse

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

1982-01-01

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

Geochemistry, Nd-Pb Isotopes, and Pb-Pb Ages of the Mesoproterozoic Pea Ridge Iron Oxide-Apatite–Rare Earth Element Deposit, Southeast Missouri

USGS Publications Warehouse

Ayuso, Robert A.; Slack, John F.; Day, Warren C.; McCafferty, Anne E.

2016-01-01

Iron oxide-apatite and iron oxide-copper-gold deposits occur within ~1.48 to 1.47 Ga volcanic rocks of the St. Francois Mountains terrane near a regional boundary separating crustal blocks having contrasting depleted-mantle Sm-Nd model ages (TDM). Major and trace element analyses and Nd and Pb isotope data were obtained to characterize the Pea Ridge deposit, improve identification of exploration targets, and better understand the regional distribution of mineralization with respect to crustal blocks. The Pea Ridge deposit is spatially associated with felsic volcanic rocks and plutons. Mafic to intermediate-composition rocks are volumetrically minor. Data for major element variations are commonly scattered and strongly suggest element mobility. Ratios of relatively immobile elements indicate that the felsic rocks are evolved subalkaline dacite and rhyolite; the mafic rocks are basalt to basaltic andesite. Granites and rhyolites display geochemical features typical of rocks produced by subduction. Rare earth element (REE) variations for the rhyolites are diagnostic of rocks affected by hydrothermal alteration and associated REE mineralization. The magnetite-rich rocks and REE-rich breccias show similar REE and mantle-normalized trace element patterns.Nd isotope compositions (age corrected) show that: (1) host rhyolites have ɛNd from 3.44 to 4.25 and TDM from 1.51 to 1.59 Ga; (2) magnetite ore and specular hematite rocks display ɛNd from 3.04 to 4.21 and TDM from 1.6 to 1.51 Ga, and ɛNd from 2.23 to 2.81, respectively; (3) REE-rich breccias have ɛNd from 3.04 to 4.11 and TDM from 1.6 to 1.51 Ga; and (4) mafic to intermediate-composition rocks range in ɛNd from 2.35 to 3.66 and in TDM from 1.66 to 1.56. The ɛNd values of the magnetite and specular hematite samples show that the REE mineralization is magmatic; no evidence exists for major overprinting by younger, crustal meteoric fluids, or by externally derived Nd. Host rocks, breccias, and magnetite ore shared a common origin from a similar source.Lead isotope ratios are diverse: (1) host rhyolite has 206Pb/204Pb from 24.261 to 50.091; (2) Pea Ridge and regional galenas have 206Pb/204Pb from 16.030 to 33.548; (3) REE-rich breccia, magnetite ore, and specular hematite rock are more radiogenic than galena; (4) REE-rich breccias have high 206Pb/204Pb (38.122–1277.61) compared to host rhyolites; and (5) REE-rich breccias are more radiogenic than magnetite ore and specular-hematite rock, having 206Pb/204Pb up to 230.65. Radiogenic 207Pb/206Pb age estimates suggest the following: (1) rhyolitic host rocks have ages of ~1.50 Ga, (2) magnetite ore is ~1.44 Ga, and (3) REE-rich breccias are ~1.48 Ga. These estimates are broadly consistent and genetically link the host rhyolite, REE-rich breccia, and magnetite ore as being contemporaneous.Alteration style and mineralogical or textural distinctions among the magnetite-rich rocks and REE-rich breccias do not correlate with different isotopic sources. In our model, magmatic fluids leached metals from the coeval felsic rocks (rhyolites), which provided the metal source reflected in the compositions of the REE-rich breccias and mineralized rocks. This model allows for the likelihood of contributions from other genetically related felsic and intermediate to more mafic rocks stored deeper in the crust. The deposit thus records an origin as a magmatic-hydrothermal system that was not affected by Nd and Pb remobilization processes, particularly if these processes also triggered mixing with externally sourced metal-bearing fluids. The Pea Ridge deposit was part of a single, widespread, homogeneous mixing system that produced a uniform isotopic composition, thus representing an excellent example of an igneous-dominated system that generated coeval magmatism and REE mineralization. Geochemical features suggest that components in the Pea Ridge deposit originated from sources in an orogenic margin. Basaltic magmatism produced by mantle decompression melting provided heat for extracting melts from the middle or lower crust. Continual addition of mafic magmas to the base of the subcontinental lithosphere, in a back-arc setting, remelted calc-alkaline rocks enriched in metals that were stored in the crust.The St. Francois Mountains terrane is adjacent to the regional TDM line (defined at a value of 1.55 Ga) that separates ~1600 Ma basement to the west, from younger basements to the east. Data for Pea Ridge straddle the TDM values proposed for the line. The Sm-Nd isotope system has been closed since formation of the deposit and the original igneous signatures have not been affected by cycles of alteration or superimposed mineralizing events. No evidence exists for externally derived Nd or Sm. The source region for metals within the Pea Ridge deposit had a moderate compositional variation and the REE-rich breccias and mineralized rocks are generally isotopically homogeneous. The Pea Ridge deposit thus constitutes a distinctive isotopic target for use as a model in identifying other mineralized systems that may share the same metal source in the St. Francois Mountains terrane and elsewhere in the eastern Granite-Rhyolite province.

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

18. VIEW OF CRUDE ORE BINS FROM WEST. WEST CRUDE ...

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

18. VIEW OF CRUDE ORE BINS FROM WEST. WEST CRUDE ORE BIN AND TRESTLE FROM TWO JOHNS TRAMLINE TO SOUTH, CRUDE ORE BIN IN FOREGROUND. MACHINE SHOP IN BACKGROUND. THE TRAM TO PORTLAND PASSED TO NORTH OF MACHINE SHOP. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

Bacterio-electric leaching of metals

DOEpatents

Lazaroff, Norman; Dugan, Patrick R.

1992-07-07

The separation of cationic materials from an ore body is assisted by the application of an electric potential, and resulting current, to the ore body, in association with iron or sulphur oxidizing bacteria. The combined process induces migration of cationic metals to a cathode suspended within the ore body so that the cationic metal can be preferentially separated from the ore body.

Bacterio-electric leaching of metals

DOEpatents

Lazaroff, Norman; Dugan, Patrick R.

1992-01-01

The separation of cationic materials from an ore body is assisted by the application of an electric potential, and resulting current, to the ore body, in association with iron or sulphur oxidizing bacteria. The combined process induces migration of cationic metals to a cathode suspended within the ore body so that the cationic metal can be preferentially separated from the ore body.

Gold deposits and occurrences of the Greater Caucasus, Georgia Republic: Their genesis and prospecting criteria

USGS Publications Warehouse

Kekelia, S.A.; Kekelia, M.A.; Kuloshvili, S.I.; Sadradze, N.G.; Gagnidze, N.E.; Yaroshevich, V.Z.; Asatiani, G.G.; Doebrich, J.L.; Goldfarb, R.J.; Marsh, E.E.

2008-01-01

The south-central part of the Greater Caucasus region, Georgia Republic, represents an extremely prospective region for significant orogenic gold deposits. Gold-bearing quartz veins are concentrated in two extensive WNW-trending belts, the Mestia-Racha and Svaneti districts, within the northern margin of the Southern Slope Zone of the Great Caucasus orogen. This metalliferous region is dominated by Early to Middle Jurassic slates, which are part of a terrane that likely accreted to the continental margin from late Paleozoic to Jurassic. The slates were subsequently intruded by both Middle to Late Jurassic and Neogene granitoids. Quartz veins in the more carbonaceous slate units are most consistently enriched in As, Au, Hg, Sb, and W, and show mineralization styles most consistent with typical orogenic gold deposits. Quartz veins in the Mestia-Racha district were mined in Soviet times for As, Sb, and W, but many of these are now being recognized as gold resource targets. The veins occur in the footwall of a thrust fault between the Southern Slope zone and an earlier accreted terrane, the Main Zone, to the north. Many veins in the district continue along strike for > 1??km and some cut Neogene intrusions, constraining ore formation to the most recent 4 to 5??million years. Gold deposition thus correlates with final collision of the Arabian plate to the south and uplift of the ore-hosting Greater Caucasus. The Zopkhito deposit, previously mined for antimony, contains an estimated 55??t Au at a cutoff grade of 0.5??g/t. The veins are localized in an area where smaller-order structures show a major change in strike from N-S to more E-W trends. A pyrite-arsenopyrite ore stage includes gold concentrated in both sulfide phases; it is overprinted by a later stibnite-dominant stage. Fluid-inclusion studies of ore samples from the Zopkhito deposit indicate minimum trapping temperatures of 300 to 350????C and 200 to 300????C for the two stages, respectively, and minimum trapping pressures of 0.2 to 0.5??kbar. Ore-forming fluids, with approximately 5 to 20??mol% non-aqueous gas, evolved from N2-dominant to CO2-dominant during evolution of the hydrothermal system. ??34S values of + 1 to + 4??? for ore-related sulfides at Zopkhito are consistent with a sedimentary rock source for the sulfur, and ??18O quartz measurements of 16 to 21??? are consistent with either a magmatic or metamorphic fluid. More than 60 gold-bearing lodes and placers in the Svaneti district occur along the thrust between the Southern Slope and Main Zones. Lode gold potential was first recognized in the historic placer district in the 1980s, with many auriferous quartz veins cutting Middle Jurassic igneous rocks. Brecciated veins in the 18??t Au Lukhra deposit cut a small granodioritic to dioritic stock; the latter intrudes Devonian schist immediately north of the thrust. Presently, there are three recognized ore zones in the deposit, with the most significant occurring over an area 140??m in length and 12??m-wide, with typical grades of 7 to 9??g/t Au. Reconnaissance fluid-inclusion studies of ore samples from the Lukhra deposit indicate minimum trapping temperatures of 220????C. Measurements of ??18Oquartz of about 10??? suggest buffering of isotopic composition by the igneous host rocks.

4. TROJAN MILL, DETAIL OF CRUDE ORE BINS FROM NORTH, ...

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

4. TROJAN MILL, DETAIL OF CRUDE ORE BINS FROM NORTH, c. 1912. SHOWS TIMBER FRAMING UNDER CONSTRUCTION FOR EAST AND WEST CRUDE ORE BINS AT PREVIOUS LOCATION OF CRUSHER HOUSE, AND SNOW SHED PRESENT OVER SOUTH CRUDE ORE BIN WITH PHASE CHANGE IN SNOW SHED CONSTRUCTION INDICATED AT EAST END OF EAST CRUDE ORE BIN. THIS PHOTOGRAPH IS THE FIRST IMAGE OF THE MACHINE SHOP, UPPER LEFT CORNER. CREDIT JW. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

Metamorphic origin of ore-forming fluids for orogenic gold-bearing quartz vein systems in the North American Cordillera: constraints from a reconnaissance study of δ15N, δD, and δ18O

USGS Publications Warehouse

Jia, Y.; Kerrich, R.; Goldfarb, R.

2003-01-01

The western North American Cordillera hosts a large number of gold-bearing quartz vein systems from the Mother Lode of southern California, through counterparts in British Columbia and southeastern Alaska, to the Klondike district in central Yukon. These vein systems are structurally controlled by major fault zones, which are often reactivated terrane-bounding sutures that formed in orogens built during accretion and subduction of terranes along the continental margin of North America. Mineralization ages span mid-Jurassic to early Tertiary and encompass much of the evolution ofthe Cordilleran orogen. Nitrogen contents and δ15N values of hydrothermal micas from veins are between 130 and 3,500 ppm and 1.7 to 5.5 per mil, respectively. These values are consistent with fluids derived from metamorphic dehydration reactions within the Phanerozoic accretion-subduction complexes, which have δ15N values of 1 to 6 per mil. The δ18O values of gold-bearing vein quartz from different locations in the Cordillera are between 14.6 and 22.2 per mil but are uniform for individual vein systems. The δD values of hydrothermal micas are between -110 and -60 per mil. Ore fluids have calculated δ18O values of 8 to 16 per mil and δD values of -65 to -10 per mil at an estimated temperature of 300δC; δD values of ore fluids do not show any latitudinal control. These results indicate a deep crustal source for the ore-forming fluids, most likely of metamorphic origin. Low δDH2O values of -120 to -130 per mil for a hydrous muscovite from the Sheba vein in the Klondike district reflect secondary exchange between recrystallizing mica and meteoric waters. Collectively, the N, H, and O isotope compositions of ore-related hydrothermal minerals indicate that the formation of these gold-bearing veins involved dilute, aqueous carbonic, and nitrogen-bearing fluids that were generated from metamorphic dehydration reactions at deep crustal levels. These data are not consistent with either mantle-derived fluids or granitoid-related magmatic fluids, nor do they support a model involving deeply circulated meteoric water.

Granitoid-associated gold mineralization in Egypt: a case study from the Atalla mine

NASA Astrophysics Data System (ADS)

Zoheir, Basem; Deshesh, Fatma; Broman, Curt; Pitcairn, Iain; El-Metwally, Ahmed; Mashaal, Shabaan

2018-06-01

Gold-bearing sulfide-quartz veins cutting mainly through the Atalla monzogranite intrusion in the Eastern Desert of Egypt are controlled by subparallel NE-trending brittle shear zones. These veins are associated with pervasive sericite-altered, silicified, and ferruginated rocks. The hosting shear zones are presumed as high-order structures of the Najd-style faults in the Central Eastern Desert ( 615-585 Ma). Ore minerals include an early pyrite-arsenopyrite (±pyrrhotite) mineralization, partly replaced by a late pyrite-galena-sphalerite-chalcopyrite (±gold/electrum ± tetrahedrite ± hessite) assemblage. Gold occurs as small inclusions in pyrite and arsenopyrite, or more commonly as intergrowths with galena and sphalerite/tetrahedrite in microfractures. Arsenopyrite geothermometry suggests formation of the early Fe-As-sulfide mineralization at 380-340 °C, while conditions of deposition of the late base metal-gold assemblage are assumed to be below 300 °C. Rare hessite, electrum, and Bi-galena are associated with sphalerite and gold in the late assemblage. The early and late sulfide minerals show consistently a narrow range of δ34S ‰ (3.4-6.5) that overlaps with sulfur isotopic values in ophiolitic rocks. The Au-quartz veins are characterized by abundant CO2 and H2O ± CO2 ± NaCl inclusions, where three-dimensional clusters of inclusions show variable aqueous/carbonic proportions and broad range of total (bimodal) homogenization temperatures. Heterogeneous entrapment of immiscible fluids is interpreted to be caused by unmixing of an originally homogenous, low salinity ( 2 eq. mass % NaCl) aqueous-carbonic fluid, during transition from lithostatic to hydrostatic conditions. Gold deposition occurred generally under mesothermal conditions, i.e., 1.3 kbar and 280 °C, and continued during system cooling to < 200 °C and pressure decrease to 0.1 kbar. Based on the vein textures, sulfur isotope values, composition of ore fluids, and conditions of ore formation, we suggest that the Atalla monzogranite intrusion acted only as a competent structural host for ore deposition from shear-related, metal-rich fluids migrated up from depth. This model is also presumed for most granitoid-associated Au deposits in the region, considering the similarity in their structural control, alteration pattern and mineralogy, and chemistry of the ore fluids.

Heterogenite vs asbolane: a mineralogical study of cobalt oxides from the DRC (Democratic Republic of the Congo)

NASA Astrophysics Data System (ADS)

Burlet, Christian; Vanbrabant, Yves; Decree, Sophie

2014-05-01

The largest cobalt ore reserves are located in DRC, the Democratic Republic of Congo. Most of cobalt is observed as black cobaltic oxide minerals: heterogenite [HCoO2] and asbolane [(Ni,Co)2-xMn(O,OH)4.nH2O] which are hardly differentiable since they exhibit similar macroscopic habit and textures. These minerals are frequently observed in similar environment (oxidized horizon of ore deposits) and they are commonly poorly-crystallized limiting their study with XRD. Their chemical composition is also not very well-constrained since they exhibit significant chemical substitutions with cations as Cu, Co, Ni, Mn. Our observations on a set of heterogenite and asbolane samples from DRC combined with samples from other localities shows that each phase, even under an amorphous form, can be readily distinguished by Raman microspectrometry. This technique is therefore attractive during ore deposit characterization campaigns or during the follow-up extraction operations where it is important to distinguish the main constituting Co-phase(s). The main advantage of this technique is its speed since no sample preparation is required during the collection Raman spectra that usually last few tens of seconds. The method provides information at a μm-scale and several points are thus required to fully characterize ore batches composed of different mineralogical phases. Our petrographical observations show also that asbolane and heterogenite mineralogical phases can coexist at a μm-scale as two distinct phases into 'heterogenite' ore. The distinction between heterogenite and asbolane from our sample set can also be conducted on a chemical base showing that heterogenite represents the richer Co-phase with variable Cu concentrations. By contrast, only Mn traces are usually observed in heterogenite minerals from DRC except in few samples, but always in lower concentration than in asbolane. The latter shows variable Mn/(Mn+Co) ratio between 0.85 and 0.3 and the decrease of this value is related to enrichment into Cu. PIC Figure 1. Example of coexisting heterogenite (Het) and asbolane (Asb), with their respective EDS spectrum.1 0.0.1 1Vanbrabant, Y., Burlet, C. and Louis, P., Mineralogical Characterization of Cobaltic Oxides from the Democratic Republic of Congo, in Ni-Co 2013, John Wiley & Sons, Inc., Hoboken, NJ, USA., Pages: 241-254, 2013

Pressurized chemical-looping combustion of coal with an iron ore-based oxygen carrier

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

Xiao, Rui; Song, Min; Zhang, Shuai

2010-06-15

Chemical-looping combustion (CLC) is a new combustion technology with inherent separation of CO{sub 2}. Most of the previous investigations on CLC of solid fuels were conducted under atmospheric pressure. A pressurized CLC combined cycle (PCLC-CC) system is proposed as a promising coal combustion technology with potential higher system efficiency, higher fuel conversion, and lower cost for CO{sub 2} sequestration. In this study pressurized CLC of coal with Companhia Valedo Rio Doce (CVRD) iron ore was investigated in a laboratory fixed bed reactor. CVRD iron ore particles were exposed alternately to reduction by 0.4 g of Chinese Xuzhou bituminous coal gasifiedmore » with 87.2% steam/N{sub 2} mixture and oxidation with 5% O{sub 2} in N{sub 2} at 970 C. The operating pressure was varied between 0.1 MPa and 0.6 MPa. First, control experiments of steam coal gasification over quartz sand were performed. H{sub 2} and CO{sub 2} are the major components of the gasification products, and the operating pressure influences the gas composition. Higher concentrations of CO{sub 2} and lower fractions of CO, CH{sub 4}, and H{sub 2} during the reduction process with CVRD iron ore was achieved under higher pressures. The effects of pressure on the coal gasification rate in the presence of the oxygen carrier were different for pyrolysis and char gasification. The pressurized condition suppresses the initial coal pyrolysis process while it also enhances coal char gasification and reduction with iron ore in steam, and thus improves the overall reaction rate of CLC. The oxidation rates and variation of oxygen carrier conversion are higher at elevated pressures reflecting higher reduction level in the previous reduction period. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX) analyses show that particles become porous after experiments but maintain structure and size after several cycles. Agglomeration was not observed in this study. An EDX analysis demonstrates that there is very little coal ash deposited on the oxygen carrier particles but no appreciable crystalline phases change as verified by X-ray diffraction (XRD) analysis. Overall, the limited pressurized CLC experiments carried out in the present work suggest that PCLC of coal is promising and further investigations are necessary. (author)« less

Petrology of Impact-Melt Rocks at the Chicxulub Multiring Basin, Yucatan, Mexico

NASA Technical Reports Server (NTRS)

Schuraytz, Benjamin C.; Sharpton, Virgil L.; Marin, Luis E.

1994-01-01

Compositions and textures of melt rocks from the upper part of the Chicxulub structure are typical of melt rocks at other large terrestrial impact structures. Apart from variably elevated iridium concentrations (less than 1.5 to 13.5 +/- 0.9 ppb) indicating nonuniform dissemination of a meteoritic component, bulk rock and phenocryst compositions imply that these melt rocks were derived exclusively from continental crust and platform-sediment target lithologies. Modest differences in bulk chemistry among samples from wells located approximately 40 km apart suggest minor variations in relative contributions of these target lithologies to the melts. Subtle variations in the compositions of early-formed pyroxene and plagioclase also support minor primary differences in chemistry between the melts. Evidence for pervasive hydrothermal alteration of the porous mesostasis includes albite, K-feldspar, quartz, epidote, chlorite, and other phyllosilicates, as well as siderophile element-enriched sulfides, suggesting the possibility that Chicxulub, like Sudbury, may host important ore deposits.

Explosibility of Metal Powders

DTIC Science & Technology

1964-01-01

299 1832 - Copper ore, sulfide , Mexic.................................................- - 100 - - - 300 1873 - Iron ore, magnetite...100 - - - 302 2076.............................................. do...................................... - - 100 - - - 303 749 - Iron ore, sulfide ...9 Pyrophoricity ............................................................... 9 Prevention of ignition and explosion

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.

26 CFR 1.272-1 - Expenditures relating to disposal of coal or domestic iron ore.

Code of Federal Regulations, 2013 CFR

2013-04-01

... domestic iron ore. 1.272-1 Section 1.272-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... Expenditures relating to disposal of coal or domestic iron ore. (a) Introduction. Section 272 provides special... sometimes referred to as a “coal royalty contract” or “iron ore royalty contract”) for the disposal of coal...

26 CFR 1.272-1 - Expenditures relating to disposal of coal or domestic iron ore.

Code of Federal Regulations, 2011 CFR

2011-04-01

... domestic iron ore. 1.272-1 Section 1.272-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... Expenditures relating to disposal of coal or domestic iron ore. (a) Introduction. Section 272 provides special... sometimes referred to as a “coal royalty contract” or “iron ore royalty contract”) for the disposal of coal...

3. EAGLE MILL, DETAIL OF CRUDE ORE BIN FROM NORTH, ...

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

3. EAGLE MILL, DETAIL OF CRUDE ORE BIN FROM NORTH, c. 1908-10. SHOWS EXPOSED CRUSHER HOUSE IN FRONT OF (SOUTH) CRUDE ORE BIN AND SNOW SHED ADDED OVER TRAM TRACKS. NOTE LACK OF EAST OR WEST CRUDE ORE BINS. CREDIT JW. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

IMPACT: How ORE Findings Have Affected Decisions in Austin and Beyond.

ERIC Educational Resources Information Center

Wilkinson, David, Ed.; Ligon, Glynn, Ed.

Over the years, findings of the Office of Research and Evaluation (ORE) of the Austin (Texas) Independent School District (AISD) have had a significant impact on decisions made in the district and sometimes beyond it. The ORE's impact in the AISD is reviewed in 16 areas. Some of the major findings are summarized: (1) ORE studies of retention in…

75 FR 68788 - Ore Knob Mine Superfund Site; Jefferson, Ashe County, North Carolina; Notice of Settlement

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-09

... ENVIRONMENTAL PROTECTION AGENCY [Docket EPA-RO4-SFUND-2010-0893, FRL-9223-8] Ore Knob Mine... Agency has entered into a settlement for reimbursement of past response costs concerning the Ore Knobe..., identified by Docket ID No. EPA-RO4- SFUND-2010-0893 or Site name Ore Knob Mine Superfund Site by one of the...

Microwave enhanced recovery of nickel-copper ore: communition and floatability aspects.

PubMed

Henda, R; Hermas, A; Gedye, R; Islam, M R

2005-01-01

A study describing the effect of microwave radiation, at a frequency of 2450 MHz, on the processes of communication and flotation of a complex sulphide nickel-copper ore is presented. Ore communication has been investigated under standard radiation-free conditions and after ore treatment in a radiated environment as a function of ore size, exposure time to radiation, and microwave power. The findings show that communication is tremendously improved by microwave radiation with values of the relative work index as low as 23% at a microwave power of 1.406 kW and after 10 s of exposure time. Communication is affected by exposure time and microwave power in a nontrivial manner. In terms of ore floatability, the experimental tests have been carried out on a sample of 75 microm in size under different exposure times. The results show that both ore concentrate recoveries and grades of nickel and copper are significantly enhanced after microwave treatment of the ore with relative increases in recovered concentrate, grade of nickel, and grade of copper of 26 wt%, 15 wt%, and 27%, respectively, at a microwave power of 1330 kW and after 30 s of exposure time.

Selective Removal of Iron from Low-Grade Ti Ore by Reacting with Calcium Chloride

NASA Astrophysics Data System (ADS)

Kang, Jungshin; Okabe, Toru H.

2017-02-01

Recently, titanium metal production by molten salt electrolysis using CaCl2 as molten salt and TiO2 or rutile (94 to 96 pct TiO2) as feedstock has been drawing attention. However, when a low-grade Ti ore (mainly FeTiO3) is used as feedstock, removal of iron (Fe) from the ore is indispensable. In this study, the influence of reaction temperature, reaction time, particle size of the ore, and source country for the ore on the removal of iron by selective chlorination using CaCl2 was assessed. Experimental results showed that the mass percent of iron in the ore decreased from 49.7 to 1.79 pct under certain conditions by selective removal of iron as FeCl2. As a result, high-grade CaTiO3 was produced when the ore particles smaller than 74 µm reacted with CaCl2 at 1240 K (967 °C) for 8 to 10 hours. Therefore, this study demonstrates that the removal of iron from the ore is feasible through the selective chlorination process using CaCl2 by optimizing the variables.

Remote sensing strategic exploration of large or superlarge gold ore deposits

NASA Astrophysics Data System (ADS)

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

1998-08-01

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

The North American iron ore industry: a decade into the 21st century

USGS Publications Warehouse

Jorgenson, John D.; Perez, A. A

2011-01-01

During the 20th century, the iron ore mining industries of Canada and the United States passed through periods of transformation. The beginning of the 21st century has seen another period of transformation, with the failure of a number of steel companies and with consolidation of control within the North American iron ore industry. Canadian and United States iron ore production and the market control structure involved are changing rapidly. Consolidation of ownership, formation of foreign joint ventures, divestitures of upstream activities by steelmakers, and industry changes to ensure availability of feedstocks all played a role in recent developments in the North American iron ore industry. Canadian and U.S. iron ore operations and their strong linkage to downstream production, although isolated, must also be considered within the context of the changing global economy. Projects using new technology to produce direct reduced iron nuggets of 96-98% iron content and other projects designed to produce steel at minesites may once again change the face of the iron ore industry. Social and environmental issues related to sustainable development have had a significant effect on the North American iron ore industry.

Stochastic production phase design for an open pit mining complex with multiple processing streams

NASA Astrophysics Data System (ADS)

Asad, Mohammad Waqar Ali; Dimitrakopoulos, Roussos; van Eldert, Jeroen

2014-08-01

In a mining complex, the mine is a source of supply of valuable material (ore) to a number of processes that convert the raw ore to a saleable product or a metal concentrate for production of the refined metal. In this context, expected variation in metal content throughout the extent of the orebody defines the inherent uncertainty in the supply of ore, which impacts the subsequent ore and metal production targets. Traditional optimization methods for designing production phases and ultimate pit limit of an open pit mine not only ignore the uncertainty in metal content, but, in addition, commonly assume that the mine delivers ore to a single processing facility. A stochastic network flow approach is proposed that jointly integrates uncertainty in supply of ore and multiple ore destinations into the development of production phase design and ultimate pit limit. An application at a copper mine demonstrates the intricacies of the new approach. The case study shows a 14% higher discounted cash flow when compared to the traditional approach.

Nanocrystalline Iron-Ore-Based Catalysts for Fischer-Tropsch Synthesis.

PubMed

Yong, Seok; Park, Ji Chan; Lee, Ho-Tae; Yang, Jung-Il; Hong, SungJun; Jung, Heon; Chun, Dong Hyun

2016-02-01

Nanocrystalline iron ore particles were fabricated by a wet-milling process using an Ultra Apex Mill, after which they were used as raw materials of iron-based catalysts for low-temperature Fischer-Tropsch synthesis (FTS) below 280 degrees C, which usually requires catalysts with a high surface area, a large pore volume, and a small crystallite size. The wet-milling process using the Ultra Apex Mill effectively destroyed the initial crystallite structure of the natural iron ores of several tens to hundreds of nanometers in size, resulting in the generation of nanocrystalline iron ore particles with a high surface area and a large pore volume. The iron-ore-based catalysts prepared from the nanocrystalline iron ore particles effectively catalyzed the low-temperature FTS, displaying a high CO conversion (about 90%) and good C5+ hydrocarbon productivity (about 0.22 g/g(cat)(-h)). This demonstrates the feasibility of using the iron-ore-based catalysts as inexpensive and disposable catalysts for the low-temperature FTS.

Lithium

USGS Publications Warehouse

Ober, J.

1998-01-01

The lithium industry can be divided into two sectors: ore concentrate producers and chemical producers. Ore concentrate producers mine lithium minerals. They beneficiate the ores to produce material for use in ceramics and glass manufacturing.

Difference in rockburst hazard in ore and coal mines

NASA Astrophysics Data System (ADS)

Lovchikov, AV

2018-03-01

In the Russian mining and engineering literature, in most cases, there is no difference in the assessment of the rockburst hazards in metal and coal mines. Nevertheless, it exists, in view of the difference in geological and geotechnical conditions of coal and ore deposits. Since ore deposits occur in the solid magmatic or metamorphic rock masses, the strongest induced earthquakes are much more powerful in ore mines than in coal mines. The main difference of rockbursting lies in the difference of natural stress state: gravity stress state in the coal fields and gravity-and-tectonic stress state in ore mines. The actual stresses are mostly vertical in the first case and horizontal in the second case, which conditions the difference in rockburst hazard in coal and ore mines.

Using the chemical analysis of magnetite to constrain various stages in the formation and genesis of the Kiruna-type chadormalu magnetite-apatite deposit, Bafq district, Central Iran

NASA Astrophysics Data System (ADS)

Heidarian, Hassan; Lentz, David; Alirezaei, Saeed; Peighambari, Sima; Hall, Douglas

2016-12-01

Textural and compositional data are presented for different types of magnetite in the Chadormalu iron deposit to discern the genesis of various styles of mineralization. Samples were chosen according to their paragenetic relations to apatite and their host setting: magnetite-apatite veins in the altered host rocks, disseminated magnetite-apatite assemblages in the marginal parts of the main ore body, and massive magnetite associated with irregular apatite veinlets from internal part of the main ore body. Scanning electron microscopy - back scatter electron (SEM-BSE) images reveal that there are three main generations of magnetite in each of the different magnetite-apatite assemblages. Primary magnetite (Mag1) features abundant porosity and a dark appearance. A second generation of magnetite (Mag2) replacing Mag1 shows a lighter appearance with both sharp and gradational contacts with the primary magnetite crystals. The two magnetite types are related to dissolution-precipitation processes due to changing physico-chemical parameters of the ore fluids. A third type of magnetite (Mag3) with a recrystallized appearance and foam-like triple junctions was mostly observed in magnetite-apatite veins in the main ore body and in veins hosted by altered rocks. Electron probe microanalyses (EPMA) were utilized to discriminate the various magnetite generations in the different magnetite-apatite assemblages. Applying published elemental discrimination diagrams shows that most primary magnetites fall into the hydrothermal- and Kiruna-type fields. Primary magnetite contains lower FeO (88.77-93.65 wt.%; average 91.5 wt.%), and higher SiO2 (0.21-2.26 wt.%; ave. 0.32 wt.%), Al2O3 (0.001-0.45 wt.%; ave. 0.053 wt.%), and CaO (0.002-0.48 wt.%; ave. 0.078 wt.%) contents, which might be related to magmatically derived fluids. Secondary magnetites have higher FeO (89.23-93.49 wt.%; ave. 92.11 wt.%), lower SiO2 (0.037-0.189 wt.%; ave. 0.072 wt.%), Al2O3 (0.004-0.072 wt.%; ave. 0.019 wt.%), and CaO (<0.034 wt.%; ave. 0.013 wt.%) possibly showing a lower contribution of magmatic fluids in the formation of Mag2. The magnetite Mag3 contains the highest FeO (91.25-93.8 wt.%; average 92.69 wt.%), low to moderate SiO2 (0.008-1.44 wt.%; ave. 0.13 wt.%), Al2O3 (<0.732 wt.%; ave. 0.059 wt.%), and CaO (<0.503 wt.%; ave. 0.072 wt.%), and appears to have formed by recrystallization of the previous two generations. The different major, minor, and trace element compositions of various magnetite generations might be due to an ore-forming fluid that was initially magmatic-hydrothermal and evolved to moderately brine-dominated meteoric fluids. The involvement of a basinal brine is supported by the occurrence of a late phase 34S-enriched pyrite in the Chadormalu deposit.

SEVENTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2012-08-30

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23more » GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 54-72 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 30 - 36 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the O-rings displayed a compression set ranging from 51 – 96%. This is greater than seen to date for any packages inspected during KAC field surveillance (24% average). For GLT O-rings, separate service life estimates have been made based on the O-ring fixture leak test data and based on compression stress relaxation (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350 – 400 ºF). However, at 300 ºF, the room temperature leak test failures to date experienced longer aging times than predicted by the CSRbased model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 ºF will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining PCV O-ring fixtures.« less

Prediction of ore fluid metal concentrations from solid solution concentrations in ore-stage calcite: Application to the Illinois-Kentucky and Central Tennessee Mississippi Valley-type districts

NASA Astrophysics Data System (ADS)

Smith-Schmitz, Sarah E.; Appold, Martin S.

2018-03-01

Knowledge of the concentrations of Zn and Pb in Mississippi Valley-type (MVT) ore fluids is fundamental to understanding MVT deposit origin. Most previous attempts to quantify the concentrations of Zn and Pb in MVT ore fluids have focused on the analysis of fluid inclusions. However, these attempts have yielded ambiguous results due to possible contamination from secondary fluid inclusions, interferences from Zn and Pb in the host mineral matrix, and uncertainties about whether the measured Zn and Pb signals represent aqueous solute or accidental solid inclusions entrained within the fluid inclusions. The purpose of the present study, therefore, was to try to determine Zn and Pb concentrations in MVT ore fluids using an alternate method that avoids these ambiguities by calculating Zn and Pb concentrations in MVT ore fluids theoretically based on their solid solution concentrations in calcite. This method was applied to the Illinois-Kentucky and Central Tennessee districts, which both contain ore-stage calcite. Experimental partition coefficient (D) values from Rimstidt et al. (1998) and Tsusue and Holland (1966), and theoretical thermodynamic distribution coefficient (KD) values were employed in the present study. Ore fluid concentrations of Zn were likely most accurately predicted by Rimstidt et al. (1998) D values, based on their success in predicting known fluid inclusion concentrations of Mg and Mn, and likely also most accurately predicted ore fluid concentrations of Fe. All four of these elements have a divalent ionic radius smaller than that of Ca2+ and form carbonate minerals with the calcite structure. For both the Illinois-Kentucky and the Central Tennessee district, predicted ore fluid Zn and Fe concentrations were on the order of up to 10's of ppm. Ore fluid concentrations of Pb could only be predicted using Rimstidt et al. (1998) D values. However, these concentrations are unlikely to be reliable, as predicted ore fluid concentrations of Sr and Ba, which like Pb also have a divalent ionic radius larger than that of Ca2+ and form carbonate minerals with the aragonite structure, did not consistently agree well with known concentrations of Sr and Ba in fluid inclusions. The ore fluid Zn concentrations predicted in the present study lie within the range of Zn concentrations typical of modern sedimentary brines and are high enough to allow deposition of the observed amounts of Zn in the Illinois-Kentucky and Central Tennessee districts within ranges of geologically reasonable times and ore fluid flow velocities. If the pH of the Illinois-Kentucky and Central pH ore fluids was as low as current evidence suggests to be possible, then these ore fluids could simultaneously have transported enough sulfide with their Zn to account for the observed amounts of sphalerite in the districts.

Ores and Climate Change - Primary Shareholders

NASA Astrophysics Data System (ADS)

Stein, Holly J.; Hannah, Judith L.

2015-04-01

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

Impact of solvent extraction organics on adsorption and bioleaching of A. ferrooxidans and L. ferriphilum

NASA Astrophysics Data System (ADS)

Hualong, Yu; Xiaorong, Liu

2017-04-01

Copper solvent extraction entrained and dissoluted organics (SX organics) in the raffinate during SX operation can contaminated chalcopyrite ores and influence bioleaching efficiency by raffinate recycling. The adsorption and bioleaching of A. ferrooxidans and L. ferriphilum with contaminated ores were investigated. The results showed that, A. ferrooxidans and L. ferriphilum cells could adsorb quickly on minerals, the adsorption rate on contaminated ores were 83% and 60%, respectively, larger than on uncontaminated ores. However, in the bioleaching by the two kinds of acid bacterias, contaminated ores presented a lower bioleaching efficiency.

O-Ring sealing arrangements for ultra-high vacuum systems

DOEpatents

Kim, Chang-Kyo; Flaherty, Robert

1981-01-01

An all metal reusable O-ring sealing arrangement for sealing two concentric tubes in an ultra-high vacuum system. An O-ring of a heat recoverable alloy such as Nitinol is concentrically positioned between protruding sealing rings of the concentric tubes. The O-ring is installed between the tubes while in a stressed martensitic state and is made to undergo a thermally induced transformation to an austenitic state. During the transformation the O-ring expands outwardly and contracts inwardly toward a previously sized austenitic configuration, thereby sealing against the protruding sealing rings of the concentric tubes.

Antimony ore in the Fairbanks district, Alaska

USGS Publications Warehouse

Killeen, Pemberton Lewis; Mertie, John B.

1951-01-01

Antimony-bearing ores in the Fairbanks district, Alaska, are found principally in two areas, the extremities of which are at points 10 miles west and 23 miles northeast of Fairbanks; and one of two minor areas lies along this same trend 30 miles farther to the northeast. These areas are probably only local manifestations of mineralization that affected a much broader area and formed antimony-bearing deposits in neighboring districts, the closest of which is 50 miles away. The ores were exposed largely as a result of lode gold mining, but at two periods in the past, high prices for antimony ore warranted an independent production and about 2500 tons of stibnite ore was shipped. The sulfide deposits occupy the same fractures along which a gold-quartz mineralization of greater economic importance occurred; and both are probably genetically related to igneous rocks which intrude the schistose country rock. The sulfide is in part contemporaneous with some late-stage quartz in which it occurs as disseminated crystals; and in part the latest filling in the mineralized zones where it forms kidney-shaped masses of essentially solid sulfide. One extremely long mass must have contained nearly 100 tons of ore, but the average of the larger kidneys is closer to several tons. Much of the ore is stibnite, with quartz as a minor impurity, and assays show the tenor to vary from 40 to 65 percent antimony. Sulphantimonites are less abundant but likewise occur as disseminated crystals and as kidney-shaped bodies. Antimony oxides appear on the weathered surface and along fractures within the sulfide ore. Deposits containing either stibnite or sulphantimonite are known at more than 50 localities, but only eighteen have produced ore and the bulk of this came from the mines. The geology of the deposit, and the nature, extent, and period of the workings are covered in the detailed descriptions of individual occurrences. Several geologic and economic factors, which greatly affect prospecting and mining for stibnite ore in the area, are outlined. The principal available ore and reserves are considered to be ores earlier mined but never shipped, ore minable from near-surface deposits, and ores recoverable as a by-product of future gold mining. The outlook for stibnite production in the district is very uncertain. Apparently the greater portion of stibnite ore has already been recovered and present operations will strip the two principal areas of the district. This conclusion is based on the scanty discoveries since the last war and the fact that the areas are so pock-marked with prospects that there is little likelihood that any other large near-surface bodies remain to be discovered. Future prospecting would essentially be limited to attempts to seek the continuation of lodes previously having high yields of stibnite.

In-situ Sr isotopic measurement of scheelite using fs-LA-MC-ICPMS

NASA Astrophysics Data System (ADS)

Li, Chao; Zhou, Limin; Zhao, Zheng; Zhang, Zhiyuan; Zhao, Hong; Li, Xinwei; Qu, Wenjun

2018-07-01

Scheelite is one of the main ore minerals in tungsten deposits, and Sr isotopic compositions of scheelite can be used to examine the petrogenesis of igneous rocks and fluid metasomatism in mineralization processes. Both thermal ionization mass spectrometer (TIMS) and femsecond laser ablation multi-collector inductively coupled plasma mass spectrometer (fs-LA-MC-ICP-MS) have been applied to analyze Sr isotopic compositions in scheelite. Here we describe a LA-MC-ICP-MS technique which can obtain in-situ, accurate, high precision 87Sr/86Sr ratios from 20 to 50 μm scheelite in line mode without requiring time-consuming mineral separation and pre-chemical procedures. We found that Ca dimers and Ca argides do not detectably affect the obtained 87Sr/86Sr ratios, and the adopted protocol overcomes interferences from Kr+, Rb+, Er2+ and Yb2+. The results of three MPI-DING reference glasses (KL2-G, ML3B-G and StHs6/80-G) are consistent with the recommended values. Here we show that the values of 87Sr/86Sr are relatively homogeneous for two scheelites from quartz veins, and are comparable to the values determined by a traditional solution method. Hence, these two scheelite samples have the potential to be reference materials for Sr isotopic determination by LA-MC-ICP-MS. To illustrate the utility of the technique, Sr isotopes of scheelites from three different types of tungsten deposits of South China are documented. The 87Sr/86Sr of scheelite from granite-related veinlet-disseminated and porphyry tungsten deposits varies systematically, showing a positive correlation between Sr content and 87Sr/86Sr ratios. These micrometer scale inhomogeneities could be explained by mixing of two components, reflecting intense fluid metasomatism during mineralization processes. High 87Sr/86Sr ratios were obtained for the scheelite samples from a quartz vein type tungsten deposit, indicating that the late stage ore-forming fluid was mainly derived from the surrounding strata. These examples show that in-situ Sr isotopic measurement of scheelite is a powerful tool to decipher the degree of fluid-rock interaction in ore-forming processes.

Study of effective utilization of iron ore sinter through arc plasma

NASA Astrophysics Data System (ADS)

Swain, Biswajit; Samal, S. K.; Mohanty, M. K.; Behera, A.; Mishra, S. C.

2018-03-01

Generation of fines is common in mining, sizing, and beneficiation and also in high-temperature metallurgical processes as the disintegration of agglomerate/compact occurs. Extraction of metallic iron from ore fines is one of the challenging aspects of iron making industries as the liberation of fines blocks, the charge burden porosity and hence hinders the reduction rate. Along with size factor, mineral composition plays a vital role in the extraction process; particularly silica. As silica has the very high tendency towards iron oxide, at comparatively low temperature, the activity of silica should be suppressed to prevent silicate phases. Adjustment of such conditions is controlled by addition of lime, but sometimes excessive slag generation increases the cost of production. In the present work, carbothermic reduction of partially reduced iron bearing pellets has been melted through 20 KW DC arc plasma furnace, and a comparative study has been made for considering different slag chemistry approaches. Pellets as aforementioned are made available from Patnaik Steel and Alloys Ltd, Odisha, having high silica content ore fines (of about 8.6%) as obtained from the chemical analysis. X-Ray analysis and optical image analyzer result of sinter thus obtained reveal that fayalite phase has major fractional value. Smelting works were done for sinter with/without adjustment of slag chemistry, where argon and nitrogen were used as plasma forming gases. A range of recovery rates (between 87-94%) is achieved by charge composition, ionizing gases, and smelting duration. It is observed that use of nitrogen as plasma forming gas increases the recovery rate than that of using only argon plasma; due to high energy flux of nitrogen which increases the enthalpy due to its diatomicity. A maximum recovery rate of about 94% is achieved for process duration of 13minutes utilizing nitrogen plasma. Smelting of charge with the addition of hydrated lime targeting melilite as final slag resulted in the formation of metallic iron as confirmed from XRD and XRF analyses. In the other hand, ferrosilicon is liberated in the metallic parts where smelting of charge was done without adjustment of slag chemistry. Both metal and slag thus obtained are characterized by XRD, XRF, microhardness and wet chemical analysis suitably.

Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources

NASA Astrophysics Data System (ADS)

Dong, Chenyin; Taylor, Mark Patrick

2017-07-01

Resolving the source of environmental contamination is the critical first step in remediation and exposure prevention. Australia's oldest silver-zinc-lead mine at Broken Hill (>130 years old) has generated a legacy of contamination and is associated with persistent elevated childhood blood lead (Pb) levels. However, the source of environmental Pb remains in dispute: current mine emissions; remobilized mine-legacy lead in soils and dusts; and natural lead from geological weathering of the gossan ore body. Multiple lines of evidence used to resolve this conundrum at Broken Hill include spatial and temporal variations in dust Pb concentrations and bioaccessibility, Pb isotopic compositions, particle morphology and mineralogy. Total dust Pb loading (mean 255 μg/m2/day) and its bioaccessibility (mean 75% of total Pb) is greatest adjacent to the active mining operations. Unweathered galena (PbS) found in contemporary dust deposits contrast markedly to Pb-bearing particles from mine-tailings and weathered gossan samples. Contemporary dust particles were more angular, had higher sulfur content and had little or no iron and manganese. Dust adjacent to the mine has Pb isotopic compositions (208Pb/207Pb: 2.3197; 206Pb/207Pb: 1.0406) that are a close match (99%) to the ore body with values slightly lower (94%) at the edge of the city. The weight of evidence supports the conclusion that contemporary dust Pb contamination in Broken Hill is sourced primarily from current mining activities and not from weathering or legacy sources.

Effect of Amount of Carbon on the Reduction Efficiency of Iron Ore-Coal Composite Pellets in Multi-layer Bed Rotary Hearth Furnace (RHF)

NASA Astrophysics Data System (ADS)

Mishra, Srinibash; Roy, Gour Gopal

2016-08-01

The effect of carbon-to-hematite molar ratio has been studied on the reduction efficiency of iron ore-coal composite pellet reduced at 1523 K (1250 °C) for 20 minutes in a laboratory scale multi-layer bed rotary hearth furnace (RHF). Reduced pellets have been characterized through weight loss measurement, estimation of porosity, shrinkage, qualitative and quantitative phase analysis by XRD. Performance parameters such as the degree of reduction, metallization, carbon efficiency, productivity, and compressive strength have been calculated to compare the process efficacy at different carbon levels in the pellets. Pellets with optimum carbon-to-hematite ratio (C/Fe2O3 molar ratio = 1.66) that is much below the stoichiometric carbon required for direct reduction of hematite yielded maximum reduction, better carbon utilization, and productivity for all three layers. Top layer exhibited maximum reduction at comparatively lower carbon level (C/Fe2O3 molar ratio <2.33) in the pellet, while bottom layer exceeded top layer reduction at higher carbon level (C/Fe2O3 molar ratio >2.33). Correlation between degree of reduction and metallization indicated non-isothermal kinetics influenced by heat and mass transfer in multi-layer bed RHF. Compressive strength of the partially reduced pellet with optimum carbon content (C/Fe2O3 molar ratio = 1.66) showed that they could be potentially used as an alternate feed in a blast furnace or any other smelting reactor.

Manganese, Metallogenium, and Martian Microfossils

NASA Technical Reports Server (NTRS)

Stein, L. Y.; Nealson, K. H.

1999-01-01

Manganese could easily be considered an abundant element in the Martian regolith, assuming that the composition of martian meteorites reflects the composition of the planet. Mineralogical analyses of 5 SNC meteorites have revealed an average manganese oxide concentration of 0.48%, relative to the 0.1% concentration of manganese found in the Earth's crust. On the Earth, the accumulation of manganese oxides in oceans, soils, rocks, sedimentary ores, fresh water systems, and hydrothermal vents can be largely attributed to microbial activity. Manganese is also a required trace nutrient for most life forms and participates in many critical enzymatic reactions such as photosynthesis. The wide-spread process of bacterial manganese cycling on Earth suggests that manganese is an important element to both geology and biology. Furthermore, there is evidence that bacteria can be fossilized within manganese ores, implying that manganese beds may be good repositories for preserved biomarkers. A particular genus of bacteria, known historically as Metallogenium, can form star-shaped manganese oxide minerals (called metallogenium) through the action of manganese oxide precipitation along its surface. Fossilized structures that resemble metallogenium have been found in Precambrian sedimentary formations and in Cretaceous-Paleogene cherts. The Cretaceous-Paleogene formations are highly enriched in manganese and have concentrations of trace elements (Fe, Zn, Cu, and Co) similar to modern-day manganese oxide deposits in marine environments. The appearance of metallogenium-like fossils associated with manganese deposits suggests that bacteria may be preserved within the minerals that they form. Additional information is contained in the original extended abstract.

[Effect of temperature on the rate of oxidation of pyrrhotite-rich sulfide ore flotation concentrate and the structure of the acidophilic chemolithoautotrophic microbial community].

PubMed

Moshchanetskii, P V; Pivovarova, T A; Belyi, A V; Kondrat'eva, T F

2014-01-01

Oxidation of flotation concentrate of a pyrrhotite-rich sulfide ore by acidophilic chemolithoautotrophic microbial communities at 35, 40, and 45 degrees C was investigated. According to the physicochemical parameters of the liquid phase of the pulp, as well as the results of analysis of the solid residue after biooxidation and cyanidation, the community developed at 40 degrees C exhibited the highest rate of oxidation. The degree of gold recovery at 35, 40, and 45 degrees C was 89.34, 94.59, and 83.25%, respectively. At 40 degrees C, the highest number of microbial cells (6.01 x 10(9) cells/mL) was observed. While temperature had very little effect on the species composition of microbial communities, except for the absence of Leptospirillum ferriphilum at 35 degrees C, the shares of individual species in the communities varied with temperature. Relatively high numbers of Sulfobacillus thermosulfidooxidans, the organism oxidizing iron and elemental sulfur at higher rates than other acidophilic chemolithotrophic species, were observed at 40 degrees C.

Development of a Rubber-Based Product Using a Mixture Experiment: A Challenging Case Study

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

Kaya, Yahya; Piepel, Gregory F.; Caniyilmaz, Erdal

2013-07-01

Many products used in daily life are made by blending two or more components. The properties of such products typically depend on the relative proportions of the components. Experimental design, modeling, and data analysis methods for mixture experiments provide for efficiently determining the component proportions that will yield a product with desired properties. This article presents a case study of the work performed to develop a new rubber formulation for an o-ring (a circular gasket) with requirements specified on 10 product properties. Each step of the study is discussed, including: 1) identifying the objective of the study and requirements formore » properties of the o-ring, 2) selecting the components to vary and specifying the component constraints, 3) constructing a mixture experiment design, 4) measuring the responses and assessing the data, 5) developing property-composition models, 6) selecting the new product formulation, and 7) confirming the selected formulation in manufacturing. The case study includes some challenging and new aspects, which are discussed in the article.« less

Effect of pressure on ore mineral solubilities under hydrothermal conditions.

USGS Publications Warehouse

Hemley, J.J.; Cygan, G.L.; d'Angelo, W. M.

1986-01-01

The combined solubilities of Fe, Zn and Pb sulphides were determined at elevated P and T in chloride solutions buffered in pH by a silicate assemblage of quartz monzonite composition plus added muscovite, and buffered in fS2 and fO2 by the assemblage pyrite-pyrrhotite-magnetite. Higher T and higher chloride concentration favour higher metal solubilities, but the P effect is opposite. At 500oC, 0.5 kbar and 1 M total chloride, Fe, Zn, Pb solubilities were 8500, 4300 and 8700 ppm, respectively, whereas at 1 kbar they were 4200, 2400 and 2600 ppm, and at 2 kbar, 1700, 800 and 1200 ppm. The P effect is of considerable importance to problems of ore-mineral transport; the metal could be carried over long distances on a decreasing P gradient so long as the T decreases were sufficient; this condition could be approximated by a near-adiabatic transport cooling path. Such a condition is probably common for hydrothermal processes involving fairly deep-seated sources of heat and mineral components.-L.C.H.

[Spectral characteristics and implications of quartz from Heliao lead-zinc polymetallic ore district in the south of Qinzhou-Hangzhou joint belt].

PubMed

Lü, Wen-Chao; Yang, Zhi-Jun; Zhou, Yong-Zhang; Li, Hong-Zhong; Zeng, Xiang-Qing; Chen, Qing; Liang, Jin; Zeng, Chang-Yu

2013-05-01

The XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rock and far away from ore body rock is pure, while the quartz in near ore body rock contains a small amount of impurities. But such small amounts of impurities did not cause apparent change in the quartz lattice parameters. From far away from ore body rock-->near ore body rock-->mineralized rock, the crystallinity and order degree of quartz are higher and higher. And the quartz in the mineralized rock has a trend to change into low symmetry quartz. It's a unique to mineralized rock that the quartz's absorption peak at 1 050 cm(-1) was split into two strongest ones. It can be used as the signs of whether exists mineralization. The cause for the quartz microstructure changes may be related to the activities of late mineralized hydrothermal fluids. Late hydrothermal influence was very weak to the quartz far away from ore body rock. And through the impact of the multi-stage hydrothermal effect, the quartz in mineralized rock may be purified by recrystallization and structural adjustment. However the quartz in near ore body rock didn't have enough hydrothermal influence, so it's not pure. Genealogy research technology is a useful technique for in-depth exploration of study area mineralization process and metallogenic regularity.

Stable Te isotope fractionation in tellurium-bearing minerals from precious metal hydrothermal ore deposits

NASA Astrophysics Data System (ADS)

Fornadel, Andrew P.; Spry, Paul G.; Haghnegahdar, Mojhgan A.; Schauble, Edwin A.; Jackson, Simon E.; Mills, Stuart J.

2017-04-01

The tellurium isotope compositions of naturally-occurring tellurides, native tellurium, and tellurites were measured by multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) and compared to theoretical values for equilibrium mass-dependent isotopic fractionation of representative Te-bearing species estimated with first-principles thermodynamic calculations. Calculated fractionation models suggest that 130/125Te fractionations as large as 4‰ occur at 100 °C between coexisting tellurates (Te VI) and tellurides (Te -II) or or native tellurium Te(0), and smaller, typically <1‰, fractionations occur between coexisting Te(-I) or Te(-II) (Au,Ag)Te2 minerals (i.e., calaverite, krennerite) and (Au,Ag)2Te minerals (i.e., petzite, hessite). In general, heavyTe/lightTe is predicted to be higher for more oxidized species, and lower for reduced species. Tellurides in the system Au-Ag-Te and native tellurium analyzed in this study have values of δ130/125Te = -1.54‰ to 0.44‰ and δ130/125Te = -0.74‰ to 0.16‰, respectively, whereas those for tellurites (tellurite, paratellurite, emmonsite and poughite) range from δ130/125Te = -1.58‰ to 0.59‰. Thus, the isotopic composition for both oxidized and reduced species are broadly coincident. Calculations of per mil isotopic variation per amu for each sample suggest that mass-dependent processes are responsible for fractionation. In one sample of coexisting primary native tellurium and secondary emmonsite, δ130/125Te compositions were identical. The coincidence of δ130/125Te between all oxidized and reduced species in this study and the apparent lack of isotopic fractionation between native tellurium and emmonsite in one sample suggest that oxidation processes cause little to no fractionation. Because Te is predominantly transported as an oxidized aqueous phase or as a reduced vapor phase under hydrothermal conditions, either a reduction of oxidized Te in hydrothermal liquids or deposition of Te from a reduced vapor to a solid is necessary to form the common tellurides and native tellurium in ore-forming systems. Our data suggest that these sorts of reactions during mineralization may account for a ∼3‰ range of δ130/125Te values. Based on the data ranges for Te minerals from various ore deposits, the underpinning geologic processes responsible for mineralization seem to have primary control on the magnitude of fractionation, with tellurides in epithermal gold deposits showing a narrower range of isotope values than those in orogenic gold and volcanogenic massive sulfide deposits.

Komatiites and nickel sulfide ores of the Black Swan area, Yilgarn Craton, Western Australia. 3: Komatiite geochemistry, and implications for ore forming processes

NASA Astrophysics Data System (ADS)

Barnes, Stephen J.; Hill, Robin E. T.; Evans, Noreen J.

2004-11-01

The Black Swan komatiite sequence is a package of dominantly olivine-rich cumulates with lesser volumes of spinifex textured rocks, interpreted as a section through an extensive komatiite lava flow field. The sequence hosts a number of nickel sulfide orebodies, including the Silver Swan massive shoot and the Cygnet and Black Swan disseminated orebodies. A large body of whole rock analyses on komatiitic rocks from the Black Swan area has been filtered for metasomatic effects. With the exception of mobile elements such as Ca and alkalis, most samples retain residual igneous geochemistry, and can be modelled predominantly by fractionation and accumulation of olivine. Whole rock MgO FeO relationships imply a relatively restricted range of olivine compositions, more primitive than the olivine which would have been in equilibrium with the transporting komatiite lavas, and together with textural data indicate that much of the cumulus olivine in the sequence was transported. Flow top compositions show evidence for chromite saturation, but the cumulates are deficient in accumulated chromite. Chromite compositions are typical of those found in compound flow-facies komatiites, and are distinct from those in komatiitic dunite bodies. Incompatible trace element abundances show three superimposed influences: control by the relative proportion of olivine to liquid; a signature of crustal contamination and an overprint of metasomatic introduction of LREE, Zr and Th. This overprint is most evident in cumulates, and relatively insignificant in the spinifex rocks. Platinum and palladium behaved as incompatible elements and are negatively correlated with MgO. They show no evidence for wholesale depletion due to sulfide extraction, which was evidently restricted to specific lava tubes or pathways. The lack of correspondence between PGE depletion and contamination by siliceous material implies that contamination alone is insufficient to generate S-saturation and ore formation in the absence of sulfide in the assimilant. Contamination signatures in spinifex-textured rocks may be a guide to Ni-sulfide mineralisation, but are not entirely reliable in the absence of other evidence. The widespread vesicularity of the sequence may be attributable to assimilated water rather than to primary mantle-derived volatiles, and cannot be taken as evidence for primary volatile-rich magmas. The characteristic signature of the Black Swan Succession is the presence of highly localised disseminated sulfide within a sequence showing more widespread evidence for crustal contamination and interaction with its immediate substrate. This has important implications for the applicability of trace element geochemistry in exploration for komatiite-hosted nickel deposits.

40 CFR 440.10 - Applicability; description of the iron ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... or its mode of occurrence; (b) mills beneficiating iron ores by physical (magnetic and nonmagnetic) and/or chemical separation; and (c) mills beneficiating iron ores by magnetic and physical separation...

40 CFR 440.10 - Applicability; description of the iron ore subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... or its mode of occurrence; (b) mills beneficiating iron ores by physical (magnetic and nonmagnetic) and/or chemical separation; and (c) mills beneficiating iron ores by magnetic and physical separation...

The future of the application of the Bi-Digital O-Ring Test in Sports Psychology.

PubMed

Ozerkan, Kemal Nuri

2005-01-01

The Bi-Digital O-Ring Test, originally developed by Dr. Omura, utilizes changes in the degree of strength of voluntary movements of muscles of the fingers under a definite muscle tonus, making Bi-Digital O-Rings, as an indicator of pathology in the body. Research in Sports Psychology can use the classical measurement methods and Bi-Digital O-Ring Test method comparatively and thus produce new findings regarding the reliability and certainty of the Bi-Digital O-Ring Test test. It seems probable that by using the non-invasive Bi-Digital O-Ring Test test, it is possible to measure enzymes, hormones and neuro-transmitters instantaneously and assess a sports person's actual psychological and physiological performance, and thereby help them reach their peak performance levels during both exercise and competitions.

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Depletion on extraction of ores or minerals from... Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or residue of prior... section 613(c)(3) (relating to extraction of ores or minerals from the ground). Thus, an acquiring...

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 4 2013-04-01 2013-04-01 false Depletion on extraction of ores or minerals from...) Insolvency Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or... the applicability of section 613(c)(3) (relating to extraction of ores or minerals from the ground...

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 4 2011-04-01 2011-04-01 false Depletion on extraction of ores or minerals from... Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or residue of prior... section 613(c)(3) (relating to extraction of ores or minerals from the ground). Thus, an acquiring...

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 4 2012-04-01 2012-04-01 false Depletion on extraction of ores or minerals from...) Insolvency Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or... the applicability of section 613(c)(3) (relating to extraction of ores or minerals from the ground...

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

NASA Technical Reports Server (NTRS)

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

1977-01-01

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

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 4 2014-04-01 2014-04-01 false Depletion on extraction of ores or minerals from...) Insolvency Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or... the applicability of section 613(c)(3) (relating to extraction of ores or minerals from the ground...

Effect of temperature and O-ring gland finish on sealing ability of Viton V747-75

NASA Technical Reports Server (NTRS)

Lach, Cynthia L.

1993-01-01

As a part of the redesign project of the Space Shuttle solid rocket motor (SRM) following the Challenger accident, the field joint was redesigned to minimize the relative joint motion caused by internal motor pressurization during ignition. The O-ring seals and glands for the field joint were designed both to accommodate structural deflections and to promote pressure-assisted sealing. Tests were conducted in various face seal fixtures to evaluate the ability of Viton V747-75 O-rings to seal for a range of temperatures and surface finishes of the redesigned O-ring gland. The effect of surface finish on the sealing performance and wear characteristics of the O-rings was evaluated during simulated launch conditions that included low-frequency vibrations, gap openings, and rapid pressurizations. The effect of contamination on the sealing performance was also investigated. The O-rings sealed throughout the 75 deg F leak check test and for the seal tests from 50 deg F to 120 deg F for the range of surface finishes investigated. Although abrasions were found in the O-rings from pressurization against the rougher finishes, these abrasions were not detrimental to sealing. Below 50 deg F, Viton V747-75 O-rings were insufficiently resilient to track the test gap opening.

Characteristics of Crushing Energy and Fractal of Magnetite Ore under Uniaxial Compression

NASA Astrophysics Data System (ADS)

Gao, F.; Gan, D. Q.; Zhang, Y. B.

2018-03-01

The crushing mechanism of magnetite ore is a critical theoretical problem on the controlling of energy dissipation and machine crushing quality in ore material processing. Uniaxial crushing tests were carried out to research the deformation mechanism and the laws of the energy evolution, based on which the crushing mechanism of magnetite ore was explored. The compaction stage and plasticity and damage stage are two main compression deformation stages, the main transitional forms from inner damage to fracture are plastic deformation and stick-slip. In the process of crushing, plasticity and damage stage is the key link on energy absorption for that the specimen tends to saturate energy state approaching to the peak stress. The characteristics of specimen deformation and energy dissipation can synthetically reply the state of existed defects inner raw magnetite ore and the damage process during loading period. The fast releasing of elastic energy and the work done by the press machine commonly make raw magnetite ore thoroughly broken after peak stress. Magnetite ore fragments have statistical self-similarity and size threshold of fractal characteristics under uniaxial squeezing crushing. The larger ratio of releasable elastic energy and dissipation energy and the faster energy change rate is the better fractal properties and crushing quality magnetite ore has under uniaxial crushing.

Nitrile/Buna N Material Failure Assessment for an O-Ring used on the Gaseous Hydrogen Flow Control Valve (FCV) of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Wingard, Doug

2006-01-01

After the rollout of Space Shuttle Discovery in April 2005 in preparation for return-to-flight, there was a failure of the Orbiter (OV-103) helium signature leak test in the gaseous hydrogen (GH2) system. Leakage was attributed to the Flow Control Valve (FCV) in Main Engine 3. The FCV determined to be the source of the leak for OV-103 is designated as LV-58. The nitrile/Buna N rubber O-ring seal was removed from LV-58, and failure analysis indicated radial cracks providing leak paths in one quadrant. Cracks were eventually found in 6 of 9 FCV O-rings among the three Shuttle Orbiters, though none were as severe as those for LV-58, OV-103. Testing by EM10 at MSFC on all 9 FCV O- rings included: laser dimensional, Shore A hardness and properties from a dynamic mechanical analyzer (DMA) and an Instron tensile machine. The following test data was obtained on the cracked quadrant of the LV-58, OV-103 O-ring: (1) the estimated compression set was only 9.5%, compared to none for the rest of the O-ring; (2) Shore A hardness for the O.D. was higher by almost 4 durometer points than for the rest of the O-ring; and (3) DMA data showed that the storage/elastic modulus E was almost 25% lower than for the rest of the O-ring. Of the 8 FCV O-rings tested on an Instron, 4 yielded tensile strengths that were below the MIL spec requirement of 1350 psi-a likely influence of rubber cracking. Comparisons were made between values of modulus determined by DNA (elastic) and Instron (Young s). Each nitrile/Buna N O-ring used in the FCV conforms to the MIL-P-25732C specification. A number of such O-rings taken from shelf storage at MSFC and Kennedy Space Center (KSC) were used to generate a reference curve of DMA glass transition temperature (Tg) vs. shelf storage time ranging from 8 to 26 years. A similar reference curve of TGA onset temperature (of rubber weight loss) vs. shelf storage time was also generated. The DMA and TGA data for the used FCV O-rings were compared to the reference curves. Correlations were also made between the DMA modulus (at 22 C) and Shore A hardness for all 9 of the FCV O-rings used among the three Shuttle Orbiters. The radial cracking in the FCV O-rings was determined to be due to ozone attack, as nitrile/Buna N rubber is susceptible to such attack. Nitrile/Buna N material under MIL-P25732C should be used in a hydraulic fluid environment to help protect it from cracking. However, the FCV O-rings were used in an air only environment. The FCV design has as much as a 9-mil gap that allows the O.D. of the O-ring to be directly exposed to ozone, pressurized air and some elevated temperatures, accelerating the weathering process that leads to O-ring cracking. Space Shuttle flights will likely not continue past 2010. Therefore, Shuttle management decided to continue using the nitrile/Buna N material for the FCVs, but have each O-ring replaced after 3 years to minimize any chances for crack initiation.

Fluid inclusion, rare earth element geochemistry, and isotopic characteristics of the eastern ore zone of the Baiyangping polymetallic Ore district, northwestern Yunnan Province, China

NASA Astrophysics Data System (ADS)

Feng, Caixia; Bi, Xianwu; Liu, Shen; Hu, Ruizhong

2014-05-01

The Baiyangping Cu-Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt, which lies between the Jinshajiang-Ailaoshan and Lancangjiang faults in western Yunnan Province, China. The source of ore-forming fluids and materials within the eastern ore zone were investigated using fluid inclusion, rare earth element (REE), and isotopic (C, O, and S) analyses undertaken on sulfides, gangue minerals, wall rocks, and ores formed during the hydrothermal stage of mineralization. These analyses indicate: (1) The presence of five types of fluid inclusion, which contain various combinations of liquid (l) and vapor (v) phases at room temperature: (a) H2O (l), (b) H2O (l) + H2O (v), (c) H2O (v), (d) CmHn (v), and (e) H2O (l) + CO2 (l), sometimes with CO2 (v). These inclusions have salinities of 1.4-19.9 wt.% NaCl equivalents, with two modes at approximately 5-10 and 16-21 wt.% NaCl equivalent, and homogenization temperatures between 101 °C and 295 °C. Five components were identified in fluid inclusions using Raman microspectrometry: H2O, dolomite, calcite, CH4, and N2. (2) Calcite, dolomitized limestone, and dolomite contain total REE concentrations of 3.10-38.93 ppm, whereas wall rocks and ores contain REE concentrations of 1.21-196 ppm. Dolomitized limestone, dolomite, wall rock, and ore samples have similar chondrite-normalized REE patterns, with ores in the Huachangshan, Xiaquwu, and Dongzhiyan ore blocks having large negative δCe and δEu anomalies, which may be indicative of a change in redox conditions during fluid ascent, migration, and/or cooling. (3) δ34S values for sphalerite, galena, pyrite, and tetrahedrite sulfide samples range from -7.3‰ to 2.1‰, a wide range that indicates multiple sulfur sources. The basin contains numerous sources of S, and deriving S from a mixture of these sources could have yielded these near-zero values, either by mixing of S from different sources, or by changes in the geological conditions of seawater sulfate reduction to sulfur. (4) The C-O isotopic analyses yield δ13C values from ca. zero to -10‰, and a wider range of δ18O values from ca. +6 to +24‰, suggestive of mixing between mantle-derived magma and marine carbonate sources during the evolution of ore-forming fluids, although potential contributions from organic carbon and basinal brine sources should also be considered. These data indicate that ore-forming fluids were derived from a mixture of organism, basinal brine, and mantle-derived magma sources, and as such, the eastern ore zone of the Baiyangping polymetallic ore deposit should be classified as a “Lanping-type” ore deposit.

SIXTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2011-08-31

A series of experiments to monitor the aging performance of Viton{reg_sign} GLT O-rings used in the Model 9975 package has been ongoing for seven years at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 F. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 F. High temperature aging continues formore » 33 GLT O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 F and higher temperatures, and in 7 fixtures aging at 300 F. No failures have yet been observed in GLT O-ring fixtures aging at 200 F for 41-60 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 F will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging within the past year at an intermediate temperature of 270 F, with hopes that they may leak before the 200 F fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 F. No failures have yet been observed in GLT-S O-ring fixtures aging at 200-300 F for up to 26 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the Orings displayed a compression set ranging from 51-96%. This is greater than seen to date for packages inspected during KAC field surveillance (24% average). For GLT O-rings, separate service life estimates have been made based on the O-ring fixture leak test data and based on compression stress relaxation (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350-400 F). However, at 300 F, the room temperature leak test failures to date experienced longer aging times than predicted by the CSR-based model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 F will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining fixtures.« less

NINTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2014-08-06

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperatures. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determinemore » if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23 GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The earliest 300 °F GLT O-ring fixture failure was observed at 34 months. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 72 - 96 months, which bounds O-ring temperatures anticipated during storage in K-Area Complex (KAC). Based on expectations that the 200 ºF fixtures will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures, thus providing additional time to failure data. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 54 - 57 months. No additional O-ring failures have been observed since the last interim report was issued. Aging and periodic leak testing will continue for the remaining PCV fixtures. Additional irradiation of several fixtures is recommended to maintain a balance between thermal and radiation exposures similar to that experienced in storage, and to show the degree of consistency of radiation response between GLT and GLT-S O-rings.« less

Hepatic retinoid levels in seven fish species (teleosts) from a tropical coastal lagoon receiving effluents from iron-ore mining and processing.

PubMed

Pereira, Adriana A; van Hattum, Bert; Brouwer, Abraham

2012-02-01

The present study was undertaken to investigate the possible effects of Fe and trace element exposure on hepatic levels of retinoids in seven fish species. Concentrations of retinoids were measured in fish collected from a coastal lagoon in Brazil that receives effluents from an iron-ore mining and processing plant. Fish from nearby coastal lagoons were also included to assess possible differences related to chemical exposure. Results indicated considerable differences in hepatic retinoid composition among the various species investigated. The most striking differences were in retinol and derivative-specific profiles and in didehydro retinol and derivative-specific profiles. The Perciformes species Geophagus brasiliensis, Tilapia rendalli, Mugil liza, and Cichla ocellaris and the Characiforme Hoplias malabaricus were characterized as retinol and derivative-specific, while the Siluriformes species Hoplosternum littorale and Rhamdia quelen were didehydro retinol and derivative-specific fish species. A negative association was observed between Al, Pb, As, and Cd and hepatic didehydro retinoid levels. Fish with higher levels of hepatic Fe, Cu, and Zn showed unexpectedly significant positive correlations with increased hepatic retinol levels. This finding, associated with the positive relationships between retinol and retinyl palmitate with lipid peroxidation, may suggest that vitamin A is mobilized from other tissues to increase hepatic antioxidant levels for protection against oxidative damage. These data show significant but dissimilar associations between trace element exposure and hepatic retinoid levels in fish species exposed to iron-ore mining and processing effluents, without apparent major impacts on fish health and condition. Copyright © 2011 SETAC.

[Emission characteristics of PM2.5 from blast furnace iron making].

PubMed

Fan, Zhen-zhen; Zhao, Ya-li; Zhao, Hao-ning; Liang, Xing-yin; Sun, Jing-wen; Wang, Bao-gui; Wang, Ya-jun

2014-09-01

Electrical low pressure impactor (ELPI) was used to online analyze the PM2.5 particle size and mass concentration distribution in the trapping field and ore tank of blast furnace iron-making plant. Results showed that the grain number concentration of PM2.5 in trapping field after dust removal was in the range of 10(5)-10(6)cm-3 , and the particle size was mainly below 0. 1 μm. While the grain number concentration of the PM2.5 in ore tank after dust removal was in the range of 10(4)-10(5) cm-3, the particle size was mainly below 1.0 μm, and the mass concentration distribution showed a single peak. The micro-morphology of PM2.5 monomer was mainly divided into two categories, spherical particles and irregular aggregates. Chemical composition analysis indicated that the concentrations of water soluble SO(2-)(4) , K+ , Ca2+ were higher than other ions in PM2.5, with the percentage of 10. 32% -28.55% , 10. 36% -12. 15% , 3.97% -15. 4% , respectively. The major elements was Fe, Si, Al, with 16. 8% -31. 62% , 2. 24% -8.76% , 1.24% -5. 89% of total mass, respectively; organic carbon and elementary carbon were 2. 7% -4. 6% and 0. 8% -1. 3% , respectively. The emission factors of PM2.5 in trapping field and in ore tank after dust removal were ranged from 0.045 to 0.085 kg t(-1) and 0.042 to 0.071 kg t-1, respectively.

4. VIEW OF RUINS OF FINE ORE MILL (FEATURE 20), ...

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

4. VIEW OF RUINS OF FINE ORE MILL (FEATURE 20), FACING SOUTHEAST. - Copper Canyon Camp of the International Smelting & Refining Company, Ruins of the Fine Ore Mill, Copper Canyon, Battle Mountain, Lander County, NV

43 CFR 9239.5-1 - Ores.

Code of Federal Regulations, 2012 CFR

2012-10-01

... OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.5-1 Ores. (a) For ores trespass in a State where there is no State law governing such trespass, the measure of damages will be as...

43 CFR 9239.5-1 - Ores.

Code of Federal Regulations, 2014 CFR

2014-10-01

... OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.5-1 Ores. (a) For ores trespass in a State where there is no State law governing such trespass, the measure of damages will be as...

43 CFR 9239.5-1 - Ores.

Code of Federal Regulations, 2011 CFR

2011-10-01

... OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.5-1 Ores. (a) For ores trespass in a State where there is no State law governing such trespass, the measure of damages will be as...

43 CFR 9239.5-1 - Ores.

Code of Federal Regulations, 2013 CFR

2013-10-01

... OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.5-1 Ores. (a) For ores trespass in a State where there is no State law governing such trespass, the measure of damages will be as...

CONTEXT VIEW SHOWING MODERN TRACKS PASSING UNDER HULETTS AND ORE ...

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

CONTEXT VIEW SHOWING MODERN TRACKS PASSING UNDER HULETTS AND ORE YARD. LOOKING NORTHEAST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

7. VIEW OF CARRIE No. 3 AND No. 4 ORE ...

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

7. VIEW OF CARRIE No. 3 AND No. 4 ORE BRIDGE, ORE YARD AND FURNACES FROM THE HOT METAL BRIDGE. - U.S. Steel Homestead Works, Blast Furnace Plant, Along Monongahela River, Homestead, Allegheny County, PA

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.

Code of Federal Regulations, 2010 CFR

2010-04-01

... domestic iron ore with a retained economic interest. 1.631-3 Section 1.631-3 Internal Revenue INTERNAL...) Sales and Exchanges § 1.631-3 Gain or loss upon the disposal of coal or domestic iron ore with a... disposes of coal (including lignite), or iron ore mined in the United States, held for more than 1 year (6...

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.

Code of Federal Regulations, 2012 CFR

2012-04-01

... domestic iron ore with a retained economic interest. 1.631-3 Section 1.631-3 Internal Revenue INTERNAL...) Sales and Exchanges § 1.631-3 Gain or loss upon the disposal of coal or domestic iron ore with a... disposes of coal (including lignite), or iron ore mined in the United States, held for more than 1 year (6...

SOUTH ELEVATION OF GOLD HILL MILL, LOOKING NORTH. THE PRIMARY ...

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

SOUTH ELEVATION OF GOLD HILL MILL, LOOKING NORTH. THE PRIMARY ORE BIN IS A CENTER, WITH A JAW CRUSHER JUST TO THE RIGHT. A CONVEYOR (MISSING) WAS USED TO CARRY CRUSHED ORE UP AND INTO THE SECONDARY ORE BIN. THE STONE RAMP TO THE LEFT OF THE ORE BIN WAS USED TO DRIVE TRUCKS UP TO DUMPING LEVEL. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

45. VIEW OF UPPER LEVEL CRUSHER ADDITION FROM CRUSHED OXIDIZED ...

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

45. VIEW OF UPPER LEVEL CRUSHER ADDITION FROM CRUSHED OXIDIZED ORE BIN. 18 INCH BELT CONVEYOR BIN FEED, LOWER CENTER, WITH STEPHENS-ADAMSON 25 TON/HR ELEVATOR SPLIT DISCHARGE (OXIDIZED/UNOXIDIZED) IN CENTER. CRUDE ORE BINS AND MACHINE SHOP BEYOND. NOTE TOP OF CRUSHED OXIDIZED ORE BIN IS BELOW TOP OF CRUDE ORE BINS. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.

Code of Federal Regulations, 2011 CFR

2011-04-01

... domestic iron ore with a retained economic interest. 1.631-3 Section 1.631-3 Internal Revenue INTERNAL...) Sales and Exchanges § 1.631-3 Gain or loss upon the disposal of coal or domestic iron ore with a... disposes of coal (including lignite), or iron ore mined in the United States, held for more than 1 year (6...

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.

Code of Federal Regulations, 2013 CFR

2013-04-01

... domestic iron ore with a retained economic interest. 1.631-3 Section 1.631-3 Internal Revenue INTERNAL...) Sales and Exchanges § 1.631-3 Gain or loss upon the disposal of coal or domestic iron ore with a... disposes of coal (including lignite), or iron ore mined in the United States, held for more than 1 year (6...

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.

Code of Federal Regulations, 2014 CFR

2014-04-01

... domestic iron ore with a retained economic interest. 1.631-3 Section 1.631-3 Internal Revenue INTERNAL...) Sales and Exchanges § 1.631-3 Gain or loss upon the disposal of coal or domestic iron ore with a... disposes of coal (including lignite), or iron ore mined in the United States, held for more than 1 year (6...

Thermodynamic Analysis of the Selective Reduction of a Nickeliferous Limonitic Laterite Ore by Hydrogen

NASA Astrophysics Data System (ADS)

Elliott, R.; Pickles, C. A.

2017-09-01

Nickeliferous limonitic laterite ores are becoming increasingly attractive as a source of metallic nickel as the costs associated with recovering nickel from the sulphide ores increase. Unlike the sulphide ores, however, the laterite ores are not amenable to concentration by conventional mineral processing techniques such as froth flotation. One potential concentrating method would be the pyrometallurgical solid state reduction of the nickeliferous limonitic ores at relatively low temperatures, followed by beneficiation via magnetic separation. A number of reductants can be utilized in the reduction step, and in this research, a thermodynamic model has been developed to investigate the reduction of a nickeliferous limonitic laterite by hydrogen. The nickel recovery to the ferronickel phase was predicted to be greater than 95 % at temperatures of 673-873 K. Reductant additions above the stoichiometric requirement resulted in high recoveries over a wider temperature range, but the nickel grade of the ferronickel decreased.

Butyl rubber O-ring seals: Revision of test procedures for stockpile materials

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

Domeier, L.A.; Wagter, K.R.

1996-12-01

Extensive testing showed little correlation between test slab and O-ring performance. New procedures, comparable to those used with the traditional test slabs, were defined for hardness, compression set, and tensile property testing on sacrificial O-ring specimens. Changes in target performance values were made as needed and were, in one case, tightened to reflect the O-ring performance data. An additional study was carried out on O-ring and slab performance vs cure cycle and showed little sensitivity of material performance to large changes in curing time. Aging and spectra of certain materials indicated that two sets of test slabs from current vendormore » were accidently made from EPDM rather than butyl rubber. Random testing found no O-rings made from EPDM. As a result, and additional spectroscope test will be added to the product acceptance procedures to verify the type of rubber compound used.« less

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

NASA Astrophysics Data System (ADS)

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

2013-06-01

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

Lead isotopes in iron and manganese oxide coatings and their use as an exploration guide for concealed mineralization

USGS Publications Warehouse

Gulson, B.L.; Church, S.E.; Mizon, K.J.; Meier, A.L.

1992-01-01

Lead isotopes from Fe and Mn oxides that coat stream pebbles from around the Mount Emmons porphyry molybdenum deposit in Colorado were studied to assess the feasibility of using Pb isotopes to detect concealed mineral deposits. The Fe/Mn oxide coatings were analyzed to determine their elemental concentrations using ICP-AES. The Pb isotope compositions of solutions from a selected suite of samples were measured, using both thermal ionization and ICP mass spectrometry, to compare results determined by the two analytical methods. Heavy mineral concentrates from the same sites were also analyzed to compare the Pb isotope compositions of the Fe/Mn coatings with those found in panned concentrates. The Fe/Mn and 206Pb/204Pb ratios of the oxide coatings are related to the lithology of the host rocks; Fe/Mn oxide coatings on pebbles of black shale have higher Fe/Mn values than do the coatings on either sandstone or igneous rocks. The shale host rocks have a more radiogenic signature (e.g. higher 206Pb/ 204Pb) than the sandstone or igneous host rocks. The Pb isotope data from sandstone and igneous hosts can detect concealed mineralized rock on both a regional and local scale, even though there are contributions from: (1) metals from the main-stage molybdenite ore deposit; (2) metals from the phyllic alteration zone which has a more radiogenic Pb isotope signature reflecting hydrothermal leaching of Pb from the Mancos Shale; (3) Pb-rich base metal veins with a highly variable Pb isotope signature; and (4) sedimentary country rocks which have a more radiogenic Pb isotope signature. An investigation of within-stream variation shows that the Pb isotope signature of the molybdenite ore zone is retained in the Fe/Mn oxide coatings and is not camouflaged by contributions from Pb-rich base-metal veins that crop out upstream. In another traverse, the Pb isotope data from Fe/Mn oxide coatings reflect a complex mixing of Pb from the molybdenite ore zone and its hornfels margin, Pb-rich base-metal veins, and sedimentary country rocks. Stream-sediment anomalies detected using oxalic acid leaches can be evaluated using Pb isotope analysesof selected geochemical anomalies. Such an evaluation procedure, given regional target Pb isotope signatures for concealed mineralization, can greatly reduce the cost of exploration for undiscovered ore deposits concealed beneath barren overburden. Lead isotope measurements on aliquots of the same solutions showed that ICP-MS determinations are of low precision and vary non-systematically when compared with the Pb isotope values of the higher precision thermal ionization method. These variations and lower precision of the ICP-MS measurements are attributed to matrix effects. ?? 1992.

Zircon-pyrochlore ores of Proterozoic Gremyakha-Vyrmes polyphase massif, Kola Peninsula: source and evolution

NASA Astrophysics Data System (ADS)

Sorokhtina, Natalia; Belyatsky, Boris; Antonov, Anton; Kononkova, Natalia; Lepekhina, Elena; Kogarko, Lia

2017-04-01

The alkaline-ultrabasic Gremyakha-Vyrmes massif occurs within the Central Kola terrane in the northern part of the Fennoscandian Shield and consists of diverse rock complexes: basic-ultrabasic rocks, foidolites, alkaline metasomatic rocks and carbonatites, alkaline granites and granosyenites. Nb-Zr ore deposit is confined to alkaline metasomatic rocks developed over foidolites. The metasomatites are represented by albitites and aegirinites occur as submeridionally orientated zones extending up to 6-8 km and several hundred meters thickness. They are mainly composed of albite and aegirine, but amphibole, annite, microcline, fluorapatite, titanite, ilmenite, pyrochlore group minerals, zircon are present [Sorokhtina et al., 2016]. Carbonatites are developed sporadically and accessory zircon but not the pyrochlore is observed only in contact zones with albitites and aegerinites. In metasomatites, zircon and pyrochlore are main rare metal minerals, which are formed at the latest stages of crystallization. Ca-dominant fluorcalcio- and hydroxycalciopyrochlores are the most abundant, whereas U-dominant pyrochlore, oxyuranobetafite, zero-valent-dominant (Ba, Sr-dominant) pyrochlore, hydro- or kenopyrochlore are rare. The pyrochlore-group minerals form heterogeneous metacrystals containing inclusions of host rock minerals, calcite, ilmenite, zircon, sulfides, and graphite. While pyrochlore is replaced by Si-rich "pyrochlore" (SiO2 is up to 18 wt.%.), cation-deficient hydrated pyrochlore, Fe-Si-Nb, U-Si-Nb, and Al-Si-Nb phases along fracture zones and margins. The early generation zircon is represented by large heterogeneous metacrystals filled with inclusions of various host rock minerals, calcite, ilmenite, thorite, thorianite and sulfides, while the late zircons are empty of inclusions. Zircons are nearly stoichiometric in composition; but intermediate zones are enriched in Pb, Y and Th, and overgrowths are enriched Hf only. According to CL and ion-microprobe analysis zircon has polygenetic nature: some relics inherited from foidolite crystallized at about 800°C, whereas the newly formed - at 600°C [Watson et al., 2006]. The time interval of the magmatic massif formation may be estimated as long as 80-100 Ma only. The basic-ultrabasic rocks and foidolites were intruded consistently at 1982 ± 6 Ma and 1894±12 according to SHRIMP-II U-Pb zircon dating, but the whole-rock Sm-Nd isotope dating has resulted in 1879±99 Ma and reflects the impact of alkaline granite intrusion (1871±9 Ma). The late differentiates from alkaline magma crystallization were the main source of rare metals for zircon-pyrochlore ores of alkaline metasomatites. The metasomatic rocks (aegirinites, albitites) and carbonatites were formed as late as 1910 ± 15 Ma (SHRIMP-II U-Pb zircon, titanite, pyrochlore). While some pyrochlore grains from metasomatites are showed that U-Pb age of ore formation is 1766 ± 24 and 1764 ± 19 respectively. That can be attributed to additional source of rare metals connected with fluids formed during regional metamorphism 1750 m.y. ago [Glebovitskii et al., 2014]. The last probable source of rare-metal material and ore-deposit evolution stage (recrystallization) is established by individual pyrochlore grain Sm-Nd and U-Pb systems and evidences tectono-thermal activity at the Paleozoic plume magmatism, which was followed by structural and chemical mineral changes. The research was done within the framework of the scientific program of Russian Academy of Sciences and state contract K41.2014.014 with Sevzapnedra. References: Watson E. B., Wark D. A., Thomas J. B. Crystallization thermometers for zircon and rutile // Contrib. Mineral. Petrol. 2006. 151, 413-433. Glebovitskii V.A., Bushmin S.A., Belyatsky B.V., Bogomolov E.S., Borozdin A.P., Savva E.V., Lebedeva Y.M. Rb-Sr age of metasomatism and ore formation in the low-temperature shear zones of the Fenno-Karelian craton, Baltic Shield // Petrology. 2014. 22(2). 184-204. Sorokhtina N.V., Kogarko L.N., Shpachenko A.K., Senin V. G. Composition and Conditions of Crystallization of zircon from the rare-metal ores of the Gremyakha-Vyrmes massif, Kola Peninsula // Geochemistry International. 2016. 54 (12). 1035-1048.

Mineral/Water Analyzer

NASA Technical Reports Server (NTRS)

1983-01-01

An x-ray fluorescence spectrometer developed for the Viking Landers by Martin Marietta was modified for geological exploration, water quality monitoring, and aircraft engine maintenance. The aerospace system was highly miniaturized and used very little power. It irradiates the sample causing it to emit x-rays at various energies, then measures the energy levels for sample composition analysis. It was used in oceanographic applications and modified to identify element concentrations in ore samples, on site. The instrument can also analyze the chemical content of water, and detect the sudden development of excessive engine wear.

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

USGS Publications Warehouse

Wallace, Stewart R.

1956-01-01

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

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELFUNLOADING BOOM IN ...

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

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELF-UNLOADING BOOM IN FRONT OF HULETTS. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

AERIAL OVERVIEW, LOOKING NORTH, WITH FORMER TCIUS STEEL ORE MINE ...

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

AERIAL OVERVIEW, LOOKING NORTH, WITH FORMER TCI-US STEEL ORE MINE HEADQUARTERS (BOTTOM) AND SUPERINTENDENT'S AND FOREMAN HOUSING ALONG MINNESOTA AVENUE AT CREST OF RED MOUNTAIN (TOP LEFT). - Muscoda Red Ore Mining Community, Bessemer, Jefferson County, AL

Microbial reduction of iron ore

DOEpatents

Hoffmann, M.R.; Arnold, R.G.; Stephanopoulos, G.

1989-11-14

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry. 11 figs.

Microbial reduction of iron ore

DOEpatents

Hoffmann, Michael R.; Arnold, Robert G.; Stephanopoulos, Gregory

1989-01-01

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry.

Toward an integrated genetic model for vent-distal SEDEX deposits

NASA Astrophysics Data System (ADS)

Sangster, D. F.

2018-04-01

Although genetic models have been proposed for vent-proximal SEDEX deposits, an equivalent model for vent-distal deposits has not yet appeared. In view of this, it is the object of this paper to present a preliminary integrated vent-distal genetic model through exploration of four major components: (i) nature of the ore-forming fluid, (ii) role of density of the unconsolidated host sediments, (iii) dynamics of sulfate reduction and (iv) depositional environment. Two sub-groups of SEDEX Pb-Zn deposits, vent-proximal and vent-distal, are widely recognized today. Of the two, the latter is by far the largest in terms of metal content with each of the 13 largest containing in excess of 7.5 M (Zn+Pb) metal. In contrast, only one vent-proximal deposit (Sullivan) falls within this size range. Vent-proximal deposits are characteristically underlain by local networks of sulfide-filled veins (commonly regarded as feeder veins) surrounded by a discordant complex of host rock alteration. These attributes are missing in vent-distal deposits, which has led to the widespread view that vent-distal ore-forming fluids have migrated unknown distances away from their vent sites. Because of the characteristic fine grain size of ore minerals, critical fluid inclusion data are lacking for vent-distal ore-stage sulfides. Consequently, hypothetical fluids such as those which formed MVT deposits (120 °C, 20% NaCl equiv.) are considered to represent vent-distal fluids as well. Such high-salinity fluids are capable of carrying significant concentrations of Pb and Zn as chloride complexes while the relatively low temperatures preclude high Cu contents. Densities of such metalliferous brines result in bottom-hugging fluids that collect in shallow saucer-shaped depressions (collector basins). Lateral metal zoning in several deposits reveals the direction from which the brines came. Relative densities of the ore-forming fluid and sediment determine whether the ore-forming fluid stabilizes on top of the sediment column or sinks into it. Metal sulfide precipitation occurs when bacterially produced H2S, diffusing upward from anoxic conditions within the sediment, reacts with metal-bearing chloride complexes in the ore-forming fluid. Since H2S is produced by bacterial sulfate reduction within the first 2 m of the sediment column even where overlain by oxic water, sulfide precipitation will always occur within the anoxic sediment regardless of where the ore-forming fluid comes to rest. Because of the high porosity of the sediment, replacement is precluded as a mechanism of sulfide emplacement in favour of void filling. Detailed textural analyses of the HYC and Howards Pass deposits have demonstrated the abundance of pre-exhalative framboidal pyrite and provide evidence for sulfate-reducing bacteria operating in these basins under normal steady-state conditions before arrival of the ore-forming fluids. The sudden presence of ore-forming fluid, however, dramatically changes the formerly steady-state situation of the local bacterial environment. A major result of this new condition is recorded in the sulfur isotope compositions of the sulfides. Whereas pre-exhalative framboidal pyrite is isotopically light, ore-stage sulfides are significantly heavier and display a reduced fractionation relative to contemporaneous seawater sulfate. Much of the reduced fractionation is linked to the increase in H2S production by sulfate-reducing bacteria. The major factor contributing to this increase is the life-saving action of sulfate-reducing bacteria during which the metal toxicity is mitigated by removal of the toxic ions by precipitating them out as sulfides. Several scenarios representing hypothetical thermochemical sulfate reduction (TSR) conditions convincingly demonstrate the extreme improbability that TSR played a role in formation of vent-distal deposits. A wide range of depositional environments is suggested by host rocks which range from impure carbonate to calcareous or dolomitic siliciclastics to normal siltstones and greywackes to calcareous and siliceous siliciclastics to highly siliceous (cherty) shales. Using the analyses of Mo concentrations as a proxy indicator of euxinia in ancient bottom waters in three vent-distal deposits ranging from Late Cambrian to Early Silurian, euxinia was excluded in all three cases. Regardless of the redox condition of the water column, however, the overriding necessary condition for vent-distal deposits to form is that the water column be quiescent to permit the establishment of a pre-exhalative sulfate-reducing bacterial community. The paper concludes with a six-stage genetic model beginning with exhalation of a dense brine and concluding with sulfide preservation in anoxic sediment.

High-grade iron ore at Windarling, Yilgarn Craton: a product of syn-orogenic deformation, hypogene hydrothermal alteration and supergene modification in an Archean BIF-basalt lithostratigraphy

NASA Astrophysics Data System (ADS)

Angerer, Thomas; Hagemann, Steffen G.; Danyushevsky, Leonid

2013-08-01

Banded iron formation (BIF)-hosted iron ore deposits in the Windarling Range are located in the lower greenstone succession of the Marda-Diemals greenstone belt, Southern Cross domain, Yilgarn Craton and constitute a total hematite-martite-goethite ore resource of minimum 52 Mt at 60 wt.% Fe (0.07 P). Banded iron formation is interlayered with high-Mg basalts at Windarling and precipitated during episodes of volcanic quiescence. Trace element content and the rare earth element (REE) ratios Y/Ho (42 to 45), Sm/Yb (1.5), together with positive La and Gd anomalies in `least-altered' hematite-magnetite-metachert-BIF indicate the precipitation from Archean seawater that was fertilised by hydrothermal vent fluids with a basaltic HREE-Y signature. Hypogene iron ore in sub-greenschist facies metamorphosed BIF formed during three distinct stages: ore stage 1 was a syn- to post-metamorphic, syn-D1, Fe-Ca-Mg-Ni-Co-P-REE metasomatism that produced local Ni-REE-rich Fe-dolomite-magnetite alteration in BIF. Hydrothermal alteration was induced by hot fluid flow controlled by brittle-ductile reactivation of BIF-basalt margins and crosscutting D1 faults. The Ni-Co-rich content of dolomite and a shift in REE ratios in carbonate-altered BIF towards Archean mafic rock signature (Y/Ho to 31 to 40, Sm/Yb to 1 to 2 and Gd/Gd* to 1.2 to 1.4) suggest that high-Mg basalts in the Windarling Range were the primary source of introduced metals. During ore stage 2, a syn-deformational and likely acidic and oxidised fluid flow along BIF-basalt margins and within D1 faults leached carbonate and precipitated lepidoblastic and anhedral/granoblastic hematite. High-grade magnetite-hematite ore is formed during this stage. Ore stage 3 hydrothermal specular hematite (spcH)-Fe-dolomite-quartz alteration was controlled by a late-orogenic, brittle, compressional/transpressional stage (D4; the regional-scale shear-zone-related D3 is not preserved in Windarling). This minor event remobilised iron oxides, carbonate and quartz to form veins and breccia but did not generate significant volumes of iron ore. Ore stage 4 involved Mesozoic(?) to recent supergene oxidation and hydration in a weathering environment reaching down to depths of ˜100 to maximum 200 m below surface. Supergene ore formation involved goethite replacement of dolomite and quartz as well as martitisation. Important `ground preparation' for supergene modification and upgrade were mainly the formation of steep D1 to D4 structures, steep BIF/basalt margins and particularly the syn-D1 to syn-D2 carbonate alteration of BIF that is most susceptible to supergene dissolution. The Windarling deposits are structurally controlled, supergene-modified hydrothermal iron ore systems that share comparable physical, chemical and ore-forming characteristics to other iron ore deposits in the Yilgarn Craton (e.g. Koolyanobbing, Beebyn in the Weld Range, Mt. Gibson). However, the remarkable variety in pre-, syn- and post-deformational ore textures (relative to D1 and D2) has not been described elsewhere in the Yilgarn and are similar to the ore deposits in high-strain zones, such as of Brazil (Quadrilátero Ferrífero or Iron Quadrangle) and Nigeria. The overall similarity of alteration stages, i.e. the sequence of hydrothermal carbonate introduction and hypogene leaching, with other greenstone belt-hosted iron ore deposits supports the interpretation that syn-orogenic BIF alteration and upgrade was crucial in the formation of hypogene-supergene iron ore deposits in the Yilgarn Craton and possibly in other Archean/Paleoproterozoic greenstone belt settings worldwide.

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE ...

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

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE BIN, LOOKING NORTHEAST. REMAINS OF A BLACKSMITH'S FORGE AND WORK CAN BE SEEN JUST BELOW THE ORE BIN (SEE CA-291-32 FOR DETAIL). ROCK FOUNDATIONS LOCATED JUST ABOVE THE ORE BIN AND ALONG THE FIRST RIDGELINE ARE TENT PADS. SEE CA-291-24 FOR IDENTICAL B&W NEGATIVE. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE ...

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

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE BIN, LOOKING NORTHEAST. REMAINS OF A BLACKSMITH'S FORGE AND WORK CAN BE SEEN JUST BELOW THE ORE BIN (SEE CA-291-32 FOR DETAIL). ROCK FOUNDATIONS LOCATED JUST ABOVE THE ORE BIN AND ALONG THE FIRST RIDGELINE ARE TENT PADS. SEE CA-291-49 (CT) FOR IDENTICAL COLOR TRANSPARENCY. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

DETAIL VIEW OF BALL MILL FEED SYSTEM, MOUTH OF CLASSIFIER, ...

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

DETAIL VIEW OF BALL MILL FEED SYSTEM, MOUTH OF CLASSIFIER, AND ORE BIN CHUTE, LOOKING EAST NORTHEAST. CRUSHED ORE FROM THE SECONDARY ORE BIN WAS INTRODUCED INTO THE FEED TROUGH VIA A CHUTE. AS THE BALL MILL TURNED, THE ROUND SCOOP ALSO TURNED IN THE TROUGH TO CHANNEL ORE INTO THE BALL MILL. SEE CA-292-14 FOR IDENTICAL B&W NEGATIVE. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

DETAIL VIEW OF BALL MILL FEED SYSTEM, MOUTH OF CLASSIFIER, ...

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

DETAIL VIEW OF BALL MILL FEED SYSTEM, MOUTH OF CLASSIFIER, AND ORE BIN CHUTE, LOOKING EAST NORTHEAST. CRUSHED ORE FROM THE SECONDARY ORE BIN WAS INTRODUCED INTO THE FEED TROUGH VIA A CHUTE. AS THE BALL MILL TURNED, THE ROUND SCOOP ALSO TURNED IN THE TROUGH TO CHANNEL ORE INTO THE BALL MILL. SEE CA-292-20 (CT) FOR IDENTICAL COLOR TRANSPARENCY. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

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.

Getting rid of the unwanted: highlights of developments and challenges of biobeneficiation of iron ore minerals-a review.

PubMed

Adeleke, Rasheed A

2014-12-01

The quest for quality mineral resources has led to the development of many technologies that can be used to refine minerals. Biohydrometallurgy is becoming an increasingly acceptable technology worldwide because it is cheap and environmentally friendly. This technology has been successfully developed for some sulphidic minerals such as gold and copper. In spite of wide acceptability of this technology, there are limitations to its applications especially in the treatment of non-sulphidic minerals such as iron ore minerals. High levels of elements such as potassium (K) and phosphorus (P) in iron ore minerals are known to reduce the quality and price of these minerals. Hydrometallurgical methods that are non-biological involving the use of chemicals are usually used to deal with this problem. However, recent advances in mining technologies favour green technologies, known as biohydrometallurgy, with minimal impact on the environment. This technology can be divided into two, namely bioleaching and biobeneficiation. This review focuses on Biobeneficiation of iron ore minerals. Biobeneficiation of iron ore is very challenging due to the low price and chemical constitution of the ore. There are substantial interests in the exploration of this technology for improving the quality of iron ore minerals. In this review, current developments in the biobeneficiation of iron ore minerals are considered, and potential solutions to challenges faced in the wider adoption of this technology are proposed.

Culturable microorganisms associated with Sishen iron ore and their potential roles in biobeneficiation.

PubMed

Adeleke, Rasheed; Cloete, T E; Khasa, D P

2012-03-01

With one of the largest iron ore deposits in the world, South Africa is recognised to be among the top ten biggest exporters of iron ore. Increasing demand and consumption of this mineral triggered search for processing technologies, which can be utilised to "purify" the low-grade iron ore minerals that contain high levels of unwanted potassium (K) and phosphorus (P). This study investigated a potential biological method that can be further developed for the full biobeneficiation of low-grade iron ore minerals. Twenty-three bacterial strains that belong to Proteobacteria, Firmicutes, Bacteroidetes and Actinobateria were isolated from the iron ore minerals and identified with sequence homology and phylogenetic methods. The abilities of these isolates to lower the pH of the growth medium and solubilisation of tricalcium phosphate were used to screen them as potential mineral solubilisers. Eight isolates were successfully screened with this method and utilised in shake flask experiments using iron ore minerals as sources of K and P. The shake flask experiments revealed that all eight isolates have potentials to produce organic acids that aided the solubilisation of the iron ore minerals. In addition, all eight isolates produced high concentrations of gluconic acid followed by relatively lower concentrations of acetic, citric and propanoic acid. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analyses also indicated extracellular polymeric substances could play a role in mineral solubilisation.

EIGHTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W. L.

2013-09-03

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23more » GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 61 - 85 months, which is still bounding to O-ring temperatures during storage in KArea Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leaktight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 41 - 45 months. Aging and periodic leak testing will continue for the remaining PCV fixtures.« less

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE ...

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

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE CARS TOWARDS CLEVELAND BULK TERMINAL BUILDINGS. LOOKING SOUTH. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELFUNLOADING SHIP UNLOADING ...

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

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELF-UNLOADING SHIP UNLOADING IN FRONT OF HULETTS. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

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

NASA Astrophysics Data System (ADS)

Kucharenko, Evgeniy; Asavin, Alex

2015-04-01

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

Radioactive rare-earth deposit at Scrub Oaks mine, Morris County, New Jersey

USGS Publications Warehouse

Klemic, Harry; Heyl, A.V.; Taylor, Audrey R.; Stone, Jerome

1959-01-01

A deposit of rare-earth minerals in the Scrub Oaks iron mine, Morris County, N. J., was mapped and sampled in 1955. The rare-earth minerals are mainly in coarse-grained magnetite ore and in pegmatite adjacent to it. Discrete bodies of rare-earth-bearing magnetite ore apparently follow the plunge of the main magnetite ore body at the north end of the mine. Radioactivity of the ore containing rare earths is about 0.2 to 0.6 mllliroentgens per hour. The principal minerals of the deposit are quartz, magnetite, hematite, albiteoligoclase, perthite and antiperthite. Xenotime and doverite aggregates and bastnaesite with intermixed leucoxene are the most abundant rare-earth minerals, and zircon, sphene, chevkinite, apatite, and monazite are of minor abundance in the ore. The rare-earth elements are partly differentiated into cerium-rich bastnaesite, chevkinite, and monazite, and yttrium-rich xenotime and doverite. Apatite, zircon, and sphene contain both cerium and yttrium group earths. Eleven samples of radioactive ore and rock average 0.009 percent uranium, 0.062 percent thorium, 1.51 percent combined rare-earth oxides including yttrium oxide and 24.8 percent iron. Scatter diagrams of sample data show a direct correlation between equivalent uranium, uranium, thorium, and combined rare^ earth oxides. Both cerium- and yttrium-group earths are abundant in the rare-earth minerals. Radioactive magnetite ore containing rare-earth minerals probably formed as a variant of the magnetite mineralization that produced the main iron ore of the Scrub Oaks deposit. The rare-earth minerals and the iron ore were deposited contemporaneously. Zircon crystals, probably deposited at the same time, have been determined by the Larsen method to be about 550 to 600 million years old (late Precambrian age). Uranium, thorium, and rare-earth elements are potential byproducts of iron in the coarse-grained magnetite ore.

9. EMPIRE STATE MINE, BOTTOM ORE BIN/SHOOT. TIN ROOF OF ...

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

9. EMPIRE STATE MINE, BOTTOM ORE BIN/SHOOT. TIN ROOF OF SOUTHERN MOST BUILDING AND UPPER ORE SHOOT VISIBLE. CAMERA POINTED EAST-NORTHEAST. - Florida Mountain Mining Sites, Empire State Mine, West side of Florida Mountain, Silver City, Owyhee County, ID

Mineralogy and geochemistry of vanadium in the Colorado Plateau

USGS Publications Warehouse

Weeks, A.D.

1961-01-01

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