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Author (up) Alvarado, J.A.C.; Balsiger, B.; Röllin, S.; Jakob, A.; Burger, M.
Title Radioactive and chemical contamination of the water resources in the former uranium mining and milling sites of Mailuu Suu (Kyrgyzstan) Type Journal Article
Year 2014 Publication Journal of Environmental Radioactivity Abbreviated Journal
Volume 138 Issue Pages 1-10
Keywords Former uranium mines, Kyrgyzstan, Mailuu Suu, Uranium contamination, Water resources
Abstract An assessment of the radioactive and chemical contamination of the water resources at the former uranium mines and processing sites of Mailuu-Suu, in Kyrgyzstan, was carried out. A large number of water samples were collected from the drinking water distribution system (DWDS), rivers, shallow aquifers and drainage water from the mine tailings. Radionuclides and trace metal contents in water from the DWDS were low in general, but were extremely high for Fe, Al and Mn. These elements were associated with the particle fractions in the water and strongly correlated with high turbidity levels. Overall, these results suggest that water from the DWDS does not represent a serious radiological hazard to the Mailuu Suu population. However, due to the high turbidities and contents of some elements, this water is not good quality drinking water. Water from artesian and dug wells were characterized by elevated levels of U (up to 10 μg/L) and some trace elements (e.g. As, Se, Cr, V and F) and anions (e.g. Cl−, NO3−, SO42−). In two artesian wells, the WHO guideline value of 10 μg/L for As in water was exceeded. As the artesian wells are used as a source of drinking water by a large number of households, special care should be taken in order to stay within the WHO recommended guidelines. Drainage water from the mine tailings was as expected highly contaminated with many chemicals (e.g. As) and radioactive contaminants (e.g. U). The concentrations of U were more than 200 times the WHO guideline value of 30 μg/L for U in drinking water. A large variation in 234U/238U isotopic ratios in water was observed, with values near equilibrium at the mine tailings and far from equilibrium outside this area (reaching ratios of 2.3 in the artesian well). This result highlights the potential use of this ratio as an indicator of the origin of U contamination in Mailuu Suu.
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ISSN 0265-931x ISBN Medium
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Call Number THL @ christoph.kuells @ alvarado_radioactive_2014 Serial 123
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Author (up) Gaj, M.; Beyer, M.; Hamutoko, J.; Uugulu, S.; Wanke, H.; Koeniger, P.; Külls, C.; Lohe, C.; Himmelsbach, T.
Title How do soil types affect stable isotope ratios of 2H and 18O under evaporation: A Fingerprint of the Niipele subbasin of the Cuvelai-Etosha basin, Namibia Type Conference Article
Year 2014 Publication EGU Geophysical Abstracts Abbreviated Journal
Volume Issue Pages 5890
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Call Number THL @ christoph.kuells @ Gaj2014soil Serial 44
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Author (up) Hamutoko, J.; Mapani, B.; Ellmies, R.; Bittner, A.; Külls, C.
Title A fingerprinting method for the identification of uranium sources in alluvial aquifers: An example from the Khan and Swakop Rivers, Namibia Type Journal Article
Year 2014 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal
Volume 72 Issue Pages 34-42
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Publisher Pergamon Place of Publication Editor
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Call Number THL @ christoph.kuells @ Hamutoko2014fingerprinting Serial 19
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Author (up) Haque, N.; Norgate, T.
Title The greenhouse gas footprint of in-situ leaching of uranium, gold and copper in Australia Type Journal Article
Year 2014 Publication Journal of Cleaner Production Abbreviated Journal
Volume 84 Issue Pages 382-390
Keywords Copper, GHG emission, Gold, In-situ leaching, LCA, Uranium
Abstract In-situ leaching (ISL) is a chemical method for recovering useful minerals and metals directly from underground ore bodies which is also referred to as ‘solution mining’. ISL is commonly used for uranium mining, accounting for about 45% of global production. The main benefits are claimed to be a lower environmental impact in terms of visual disturbances, emissions, lower energy use, cost compared with conventional open-cut or underground mining methods, and potential utilisation of lower grade resources. However, there is a lack of reported studies on the assessment of the environmental impacts of ISL, particularly greenhouse gas (GHG) emissions using life cycle assessment (LCA) methodology. The SimaPro LCA software was used to estimate the GHG footprint of the ISL of uranium, gold and copper. The total GHG emissions were estimated to be 38.0 kg CO2-e/kg U3O8 concentrate (yellowcake), 29 t CO2-e/kg gold, and 4.78 kg CO2-e/kg Cu. The GHG footprint of ISL uranium was significantly lower than that of conventional mining, however, the footprints of copper and gold were not much less compared with conventional mining methods. This is due to the lower ore grade of ISL deposits and recovery compared with high ore grades and recovery of conventional technology. Additionally, the use of large amount of electricity for pumping in case of ISL contributes to this result. The electricity consumed in pumping leaching solutions was by far the greatest contributor to the well-field related activities associated with ISL of uranium, gold and copper. The main strategy to reduce the GHG footprint of ISL mining should be to use electricity derived from low emission sources. In particular, renewable sources such as solar would be suitable for ISL as these operations are typically in remote locations with smaller deposits compared with conventional mining sites.
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ISSN 0959-6526 ISBN Medium
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Call Number THL @ christoph.kuells @ haque_greenhouse_2014 Serial 208
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Author (up) Ingham, E.S.; Cook, N.J.; Cliff, J.; Ciobanu, C.L.; Huddleston, A.
Title A combined chemical, isotopic and microstructural study of pyrite from roll-front uranium deposits, Lake Eyre Basin, South Australia Type Journal Article
Year 2014 Publication Geochimica et Cosmochimica Acta Abbreviated Journal
Volume 125 Issue Pages 440-465
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Abstract The common sulfide mineral pyrite is abundant throughout sedimentary uranium systems at Pepegoona, Pepegoona West and Pannikan, Lake Eyre Basin, South Australia. Combined chemical, isotopic and microstructural analysis of pyrite indicates variation in fluid composition, sulfur source and precipitation conditions during a protracted mineralization event. The results show the significant role played by pyrite as a metal scavenger and monitor of fluid changes in low-temperature hydrothermal systems. In-situ micrometer-scale sulfur isotope analyses of pyrite demonstrated broad-scale isotopic heterogeneity (δ34S=−43.9 to +32.4‰VCDT), indicative of complex, multi-faceted pyrite evolution, and sulfur derived from more than a single source. Preserved textures support this assertion and indicate a genetic model involving more than one phase of pyrite formation. Authigenic pyrite underwent prolonged evolution and recrystallization, evidenced by a genetic relationship between archetypal framboidal aggregates and pyrite euhedra. Secondary hydrothermal pyrite commonly displays hyper-enrichment of several trace elements (Mn, Co, Ni, As, Se, Mo, Sb, W and Tl) in ore-bearing horizons. Hydrothermal fluids of magmatic and meteoric origins supplied metals to the system but the geochemical signature of pyrite suggests a dominantly granitic source and also the influence of mafic rock types. Irregular variation in δ34S, coupled with oscillatory trace element zonation in secondary pyrite, is interpreted in terms of continuous variations in fluid composition and cycles of diagenetic recrystallization. A late-stage oxidizing fluid may have mobilized selenium from pre-existing pyrite. Subsequent restoration of reduced conditions within the aquifer caused ongoing pyrite re-crystallization and precipitation of selenium as native selenium. These results provide the first qualitative constraints on the formation mechanisms of the uranium deposits at Beverley North. Insights into depositional conditions and sources of both sulfide and uranium mineralization and an improved understanding of pyrite geochemistry can also underpin an effective vector for uranium exploration at Beverley North and other sedimentary systems of the Lake Eyre Basin, as well as in comparable geological environments elsewhere.
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ISSN 0016-7037 ISBN Medium
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Call Number THL @ christoph.kuells @ ingham_combined_2014 Serial 188
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