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Author Kurmanseiit, M.B.; Tungatarova, M.S.; Royer, J.-J.; Aizhulov, D.Y.; Shayakhmetov, N.M.; Kaltayev, A.
Title (down) Streamline-based reactive transport modeling of uranium mining during in-situ leaching: Advantages and drawbacks Type Journal Article
Year 2023 Publication Hydrometallurgy Abbreviated Journal
Volume 220 Issue Pages 106107
Keywords 3D modeling, In-situ leaching, Reactive transport model, Streamlines, Uranium recovery
Abstract Reactive transport modeling is known to be computationally intensive when applied to 3D problems. Transforming sequential computing on the computer processor units (CPU) into parallelized computation on the high-performance parallel graphic processor units (GPU) is a classical approach to increasing computational performance. Another complementary approach is to decompose a complex 3D modeling problem into a set of simpler 1D problems using streamline approaches which can be easily parallelized, therefore reducing computation time. This paper investigates solutions to the equations governing dissolution and transport using streamlines coupled with a parallelization approach. In addition, an analytical solution to the dissolution and transfer equations of uranium describing the In-Situ Leaching (ISL) mining recovery is found using an approximation series to the 2nd order. The analytical solution is compared to the 1D numerical resolution along the streamlines and to the 3D simulation results superimposed on the streamline. Both approaches give similar results with a relative error of \textless2 % (2%). The proposed methodology is then applied to a case study in which the classical 3D resolution is compared to the newly suggested streamline solution, demonstrating that the streamline approach increases computational performances by a factor ranging from hundred to thousand depending on the complexity of the grid-block model.
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ISSN 0304-386x ISBN Medium
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Call Number THL @ christoph.kuells @ kurmanseiit_streamline-based_2023 Serial 190
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Author Külls, C.; Bittner, A.; Marx, V.
Title (down) Strategic Assessment of Water Resources for the Erongo Uranium Province Type Miscellaneous
Year 2013 Publication IMWA Conf. Abbreviated Journal
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Call Number THL @ christoph.kuells @ Kuells2012strategic Serial 70
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Author United Nations
Title (down) Stampriet Transboundary Aquifer System Assessment: governance of Groundwater resources in Transboundary Aquifers (GGRETA), phase 1: technical report Type Miscellaneous
Year 1998 Publication Abbreviated Journal
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Call Number THL @ christoph.kuells @ Serial 286
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Author Mühr-Ebert, E.L.; Wagner, F.; Walther, C.
Title (down) Speciation of uranium: Compilation of a thermodynamic database and its experimental evaluation using different analytical techniques Type Journal Article
Year 2019 Publication Applied Geochemistry Abbreviated Journal
Volume 100 Issue Pages 213-222
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Abstract Environmental hazards are caused by uranium mining legacies and enhanced radioactivity in utilized groundwater and surface water resources. Knowledge of uranium speciation in these waters is essential for predicting radionuclide migration and for installing effective water purification technology. The validity of the thermodynamic data for the environmental media affected by uranium mining legacies is of utmost importance. Therefore, a comprehensive and consistent database was established according to current knowledge. The uranium data included in the database is based on the NEA TDB (Guillaumont et al., 2003) and is modified or supplemented as necessary e.g. for calcium and magnesium uranyl carbonates. The specific ion interaction theory (Brönsted, 1922) is used to estimate activity constants, which is sufficient for the considered low ionic strengths. The success of this approach was evaluated by comparative experimental investigations and model calculations (PHREEQC (Parkhurst and Appelo, 1999)) for several model systems. The waters differ in pH (2.7–9.8), uranium concentration (10−9-10−4 mol/L) and ionic strength (0.002–0.2 mol/L). We used chemical extraction experiments, ESI-Orbitrap-MS and time-resolved laser-induced fluorescence spectroscopy (TRLFS) to measure the uranium speciation. The latter method is nonintrusive and therefore does not change the chemical composition of the investigated waters. This is very important, because any change of the system under study may also change the speciation.
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ISSN 0883-2927 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ muhr-ebert_speciation_2019 Serial 142
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Author N, D.; Panda, B.; S, C.; V, P.M.; Singh, D.K.; L, R.A.; Sahoo, S.K.
Title (down) Spatio-temporal variations of Uranium in groundwater: Implication to the environment and human health Type Journal Article
Year 2021 Publication Science of The Total Environment Abbreviated Journal
Volume 775 Issue Pages 145787
Keywords Groundwater, Health risk, Speciation, Stable isotopes, Statistics, Uranium
Abstract Groundwater overexploitation has resulted in huge scarcity and increase in the demand for water and food security in India. Groundwater in India has been observed to have experienced various water quality issues like arsenic, fluoride, and Uranium (U) contamination, leading to risk in human health. Markedly, the health risk of higher U in drinking water, as well as its chemical toxicity in groundwater have adverse effects on human. This study has reported occurrence of U as an emerging and widespread phenomenon in South Indian groundwater. Data on U in groundwater were generated from 284 samples along the Cretaceous Tertiary boundary within 4 seasons viz. pre-monsoon (PRM), southwest monsoon (SWM), northeast monsoon (NEM), and post-monsoon (POM). High U concentrations (74 μgL−1) showed to be above the World Health Organization’s provisional guideline value of 30 μgL−1. The geochemical, stable isotope and geophysical studies suggested that U in groundwater could vary with respect to season and was noted to be highest during NEM. The bicarbonate (HCO3) released by weathering process during monsoon could affect the saturation index (SI)Calcite and carbonate species of U. However, the primary source of U was found to be due to geogenic factors, like weathering, dissolution, and groundwater level fluctuation, and that, U mobilization could be enhanced due to anthropogenic activities. The findings further indicated that groundwater in the study area has reached the alarming stage of chemical toxicity. Hence, it is urgent and imperative that workable management strategies for sustainable drinking water source be developed and preventive measures be undertaken, relative to these water quality concerns to mitigate their disconcerting effect on human health.
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ISSN 0048-9697 ISBN Medium
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Call Number THL @ christoph.kuells @ n_spatio-temporal_2021 Serial 146
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