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Author Hebert, B.; Baron, F.; Robin, V.; Lelievre, K.; Dacheux, N.; Szenknect, S.; Mesbah, A.; Pouradier, A.; Jikibayev, R.; Roy, R.; Beaufort, D.
Title (down) Quantification of coffinite (USiO4) in roll-front uranium deposits using visible to near infrared (Vis-NIR) portable field spectroscopy Type Journal Article
Year 2019 Publication Journal of Geochemical Exploration Abbreviated Journal
Volume 199 Issue Pages 53-59
Keywords Coffinite, Mineral quantification, Near infrared, Ore exploration, Portable field spectroscopy, Roll-front deposits
Abstract Coffinite (USiO4) is a common uranium-bearing mineral of roll-front uranium deposits. This mineral can be identified by the visible near infrared (Vis-NIR) portable field spectrometers used in mining exploration. However, due to the low detection limits and associated errors, the quantification of coffinite abundance in the mineralized sandstones or sandy sediments of roll-front uranium deposits using Vis-NIR spectrometry requires a specific methodological development. In this study, the 1135 nm absorption band area is used to quantify the abundance of coffinite. This absorption feature does not interfere with NIR absorption bands of any other minerals present in natural sands or sandstones of uranium roll-front deposits. The correlation between the 1135 nm band area and coffinite content was determined from a series of spectra measured from prepared mineral mixtures. The samples were prepared with a range of weighted amounts of arenitic sands and synthetic coffinite simulating the range of uranium concentration encountered in roll-front uranium deposits. The methodology presented in this study provides the quantification of the coffinite content present in sands between 0.03 wt% to 1 wt% coffinite with a detection limit as low as 0.005 wt%. The integrated area of the 1135 nm band is positively correlated with the coffinite content of the sand in this range, showing that the method is efficient to quantify coffinite concentrations typical of roll-front uranium deposits. The regression equation defined in this study was then used as a reference to predict the amount of natural coffinite in a set of mineralized samples from the Tortkuduk uranium roll-front deposit (South Kazakhstan).
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ISSN 0375-6742 ISBN Medium
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Call Number THL @ christoph.kuells @ hebert_quantification_2019 Serial 184
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Author Pastukhov, A.M.; Rychkov, V.N.; Smirnov, A.L.; Skripchenko, S.Y.; Poponin, N.A.
Title (down) Purification of in situ leaching solution for uranium mining by removing solids from suspension Type Journal Article
Year 2014 Publication Minerals Engineering Abbreviated Journal
Volume 55 Issue Pages 1-4
Keywords Bag filter, Firm particles, In situ leaching mining, Injection wells, Intake capacity, Purification
Abstract This study investigated the process of in situ leaching (ISL) method of uranium mining, and the removal of solid particles from the leaching solution. Investigations were carried out for 4months. The content of firm suspensions in the productive solutions arriving from the well field was up to standard of 3–5mg/l. After keeping in a settler of productive solutions within one hour concentration of suspensions decreases to 2–2.5mg/l. To increase the life of the wells requires more fine purification of the ISL solutions. The best results can be obtained but using filtration. Bag filters were used in experiments carried out at the extraction site. All samples of polypropylene bag filter was produced by the Tamfelt Corporation. The best results were obtained for fabrics S-51M03-L2K4 (pore size 3μm). After three month of trials following indicators of wells work were fixed: on the trial cell decrease in intake capacity did not occur; on the other cells of well field injectability of holes for the same period of time decreased for 15–40%. The results illustrated the high efficiency of this method, which allows injection wells to reach a constant intake capacity, making it possible for technological cells to achieve a constant productivity and balance. Purification of solutions allows to reduce acidulation term of new technological cells from 3–4 to 1.5–2months.
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ISSN 0892-6875 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ pastukhov_purification_2014 Serial 204
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Author Jroundi, F.; Descostes, M.; Povedano-Priego, C.; Sánchez-Castro, I.; Suvannagan, V.; Grizard, P.; Merroun, M.L.
Title (down) Profiling native aquifer bacteria in a uranium roll-front deposit and their role in biogeochemical cycle dynamics: Insights regarding in situ recovery mining Type Journal Article
Year 2020 Publication Science of The Total Environment Abbreviated Journal
Volume 721 Issue Pages 137758
Keywords Bacterial diversity, Bioremediation, In-situ recovery, Natural attenuation, Network analysis, Uranium
Abstract A uranium-mineralized sandy aquifer, planned for mining by means of uranium in situ recovery (U ISR), harbors a reservoir of bacterial life that may influence the biogeochemical cycles surrounding uranium roll-front deposits. Since microorganisms play an important role at all stages of U ISR, a better knowledge of the resident bacteria before any ISR actuations is essential to face environmental quality assessment. The focus here was on the characterization of bacteria residing in an aquifer surrounding a uranium roll-front deposit that forms part of an ISR facility project at Zoovch Ovoo (Mongolia). Water samples were collected following the natural redox zonation inherited in the native aquifer, including the mineralized orebody, as well as compartments located both upstream (oxidized waters) and downstream (reduced waters) of this area. An imposed chemical zonation for all sensitive redox elements through the roll-front system was observed. In addition, high-throughput sequencing data showed that the bacterial community structure was shaped by the redox gradient and oxygen availability. Several interesting bacteria were identified, including sulphate-reducing (e.g. Desulfovibrio, Nitrospira), iron-reducing (e.g. Gallionella, Sideroxydans), iron-oxidizing (e.g. Rhodobacter, Albidiferax, Ferribacterium), and nitrate-reducing bacteria (e.g. Pseudomonas, Aquabacterium), which may also be involved in metal reduction (e.g. Desulfovibrio, Ferribacterium, Pseudomonas, Albidiferax, Caulobacter, Zooglea). Canonical correspondence analysis (CCA) and co-occurrence patterns confirmed strong correlations among the bacterial genera, suggesting either shared/preferred environmental conditions or the performance of similar/complementary functions. As a whole, the bacterial community residing in each aquifer compartment would appear to define an ecologically functional ecosystem, containing suitable microorganisms (e.g. acidophilic bacteria) prone to promote the remediation of the acidified aquifer by natural attenuation. Assessing the composition and structure of the aquifer’s native bacteria is a prerequisite for understanding natural attenuation and predicting the role of bacterial input in improving ISR efficiency.
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ISSN 0048-9697 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ jroundi_profiling_2020 Serial 177
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Author Demuth, S.; Külls, C.
Title (down) Probability analysis and regional aspects of droughts in southern Germany Type Journal Article
Year 1997 Publication Sustainability of Water Resources under Increasing Uncertainty Abbreviated Journal
Volume Issue 240 Pages 97
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Call Number THL @ christoph.kuells @ Demuth1997probability Serial 35
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Author Salbu, B.
Title (down) Preface: uranium mining legacy issue in Central Asia Type Journal Article
Year 2013 Publication Journal of Environmental Radioactivity Abbreviated Journal
Volume 123 Issue Pages 1-2
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ISSN 0265-931x ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ salbu_preface_2013 Serial 125
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