The possibility of using mine wastes (low-sulfide tailings and waste rocks) as cover components to prevent acid mine drainage (AMD) generation from highly reactive tailings was previously investigated through a laboratory-based characterization of reactive tailings and cover materials (Part 1 of this study). Characterization results showed that the reactive tailings are highly acid-generating, and that the mine waste materials that were used in this study are non-acid-generating and have suitable hydrogeological and geochemical properties to be used in a cover with capillary barrier effects (CCBE). In order to further investigate the use of low-sulfide mining materials in the reclamation of highly reactive tailings, a large laboratory-based column and a field cell simulating a CCBE were constructed. The instrumented field cell used the same configuration and materials as the laboratory column. This paper presents the main findings from 504 days (column test) and three seasons (field test) of monitoring, and compares the hydrogeochemical behavior observed at the two scales. The results show that a CCBE made with low-sulfide mine wastes would be efficient at reducing oxygen fluxes and limiting AMD generation from highly reactive tailings at the laboratory and intermediate scale. However, at these two scales, the concentrations of some contaminants were not reduced to levels of the legally imposed environmental objectives. The results also showed differences in metal and sulfate concentrations in the drainage waters between the laboratory and field scales. The outcomes from this investigation highlight that the previous oxygen flux design targets and the typical configurations of multilayer covers developed for fresh non-oxidized tailings or pre-oxidized tailings may not always be directly applicable for fresh or pre-oxidized highly reactive tailings.

中文翻译：

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回收的高活性尾矿的水文地球化学行为，第2部分：用矿山废料制成的覆盖物的实验室和现场结果

以前已经通过基于实验室的反应性尾矿和表层材料表征研究了使用矿山废料（低硫化物尾矿和rocks石）作为掩盖成分来防止高反应性尾矿产生酸性矿井排水（AMD）的可能性（第1部分，第1部分）。这项研究）。表征结果表明，反应性尾矿高产酸，并且本研究中使用的矿山废料不产酸，并且具有合适的水文地质和地球化学特性，可用于具有毛细屏障效应的覆盖层（CCBE） ）。为了进一步研究低硫化物采矿材料在高反应性尾矿的回收中的用途，构建了大型的实验室用柱和模拟CCBE的现场单元。仪器化的现场单元使用与实验室色谱柱相同的配置和材料。本文介绍了从504天（柱试验）和三个季节（田间试验）监测的主要发现，并比较了在两个尺度上观察到的水文地球化学行为。结果表明，用低硫化物矿山废料制得的CCBE可有效减少氧气通量并限制实验室和中等规模的高反应性尾矿产生AMD。但是，在这两个级别上，某些污染物的浓度并未降低到法律规定的环境目标的水平。结果还表明，实验室规模和田间规模之间的排水中金属和硫酸盐浓度存在差异。