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Klock, H., Külls, C., & Udluft, P. (2000). Estimation of relative recharge values for the northern Kalahari catchment, Namibia. Journal of African Earth Sciences, 30(4), 47–48.
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Benito, G., Rohde, R., Seely, M., Külls, C., Dahan, O., Enzel, Y., et al. (2010). Management of alluvial aquifers in two southern African ephemeral rivers: implications for IWRM. Water Resources Management, 24(4), 641–667.
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Baram, S., Ronen, Z., Kurtzman, D., Külls, C., & Dahan, O. (2013). Desiccation-crack-induced salinization in deep clay sediment. Hydrology and Earth System Sciences, 17(4), 1533.
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Liu, Z., Tan, K., Li, C., Li, Y., Zhang, C., Song, J., et al. (2023). Geochemical and S isotopic studies of pollutant evolution in groundwater after acid in situ leaching in a uranium mine area in Xinjiang. Nuclear Engineering and Technology, 55(4), 1476–1484.
Abstract: Laboratory experiments and point monitoring of reservoir sediments have proven that stable sulfate reduction (SSR) can lower the concentrations of toxic metals and sulfate in acidic groundwater for a long time. Here, we hypothesize that SSR occurred during in situ leaching after uranium mining, which can impact the fate of acid groundwater in an entire region. To test this, we applied a sulfur isotope fractionation method to analyze the mechanism for natural attenuation of contaminated groundwater produced by acid in situ leaching of uranium (Xinjiang, China). The results showed that δ34S increased over time after the cessation of uranium mining, and natural attenuation caused considerable, area-scale immobilization of sulfur corresponding to retention levels of 5.3%–48.3% while simultaneously decreasing the concentration of uranium. Isotopic evidence for SSR in the area, together with evidence for changes of pollutant concentrations, suggest that area-scale SSR is most likely also important at other acid mining sites for uranium, where retention of acid groundwater may be strengthened through natural attenuation. To recapitulate, the sulfur isotope fractionation method constitutes a relatively accurate tool for quantification of spatiotemporal trends for groundwater during migration and transformation resulting from acid in situ leaching of uranium in northern China.
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Zeng, S., Shen, Y., Sun, B., Tan, K., Zhang, S., & Ye, W. (2022). Fractal kinetic characteristics of uranium leaching from low permeability uranium-bearing sandstone. Nuclear Engineering and Technology, 54(4), 1175–1184.
Abstract: The pore structure of uranium-bearing sandstone is one of the critical factors that affect the uranium leaching performance. In this article, uranium-bearing sandstone from the Yili Basin, Xinjiang, China, was taken as the research object. The fractal characteristics of the pore structure of the uranium-bearing sandstone were studied using mercury intrusion experiments and fractal theory, and the fractal dimension of the uranium-bearing sandstone was calculated. In addition, the effect of the fractal characteristics of the pore structure of the uranium-bearing sandstone on the uranium leaching kinetics was studied. Then, the kinetics was analyzed using a shrinking nuclear model, and it was determined that the rate of uranium leaching is mainly controlled by the diffusion reaction, and the dissolution rate constant (K) is linearly related to the pore specific surface fractal dimension (DS) and the pore volume fractal dimension (DV). Eventually, fractal kinetic models for predicting the in-situ leaching kinetics were established using the unreacted shrinking core model, and the linear relationship between the fractal dimension of the sample’s pore structure and the dissolution rate during the leaching was fitted.
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