Geochemical Characterization and Reactive Transport Simulation of Metal Leaching and Acid Generation in Waste Rock from the Ekati Diamond Mine, NT

采矿活动产生大量废物，可能对水和土壤质量以及接受采矿的生态系统的健康产生不利影响。含硫化物的矿山废石，包括不经济的废石，风化会产生酸性排水，并促进无机成分的释放，包括金属(固体)S和硫酸盐。Ekati钻石矿位于西北部耶洛奈夫东北约300公里处。Ekati将产生约820公吨的废石，其中包括约50公吨来自鸽子露天矿的废石，该废石主要由混合变质岩和花岗岩-辉绿岩组成。在现场条件下，这种材料具有不确定的产酸潜力；这一发现不同于使用岩心样品电荷进行的实验室规模湿度电池测试的结果，后者将岩石归类为潜在产酸。拟议研究项目的范围是通过现场样品收集、实验室实验和表征以及反应传输模拟的综合方案，重新评估鸽子坑废石的产酸和金属淋滤潜力。拟议的项目将提供对废石风化可能产生的潜在长期水质影响的关键见解，并建立比例关系以预测现场污染物的释放、传输和衰减；这些结果将由Ekati整合到封堵规划和盖子设计中。

Mining activities generate significant quantities of waste materials, which can negatively impact water and soil quality, and the health of receiving ecosystems. Weathering of sulfide-bearing mine wastes, including uneconomic waste rock, can generate acidic drainage and promote the release of inorganic constituents, including metal(loid)s and sulfate. The Ekati Diamond Mine is located approximately 300 km northeast of Yellowknife, NWT. Ekati will generate ~820 MT of waste rock, including ~50 MT of waste rock from the Pigeon Open Pit, which is comprised primarily of mixed metasediment and granite-diabase. Under field conditions, the material is of uncertain acid-generating potential; this finding differs from results of laboratory-scale humidity-cell tests conducted using core-sample charges, which classified the rock as potentially acid generating. The scope of the proposed research project is to re-assess the acid-generating and metal-leaching potential of waste rock from the Pigeon Pit through an integrated program of field-sample collection, laboratory experimentation and characterization, and reactive transport modelling. The proposed project will provide critical insights into the potential long-term water-quality impacts that may arise from waste-rock weathering, and develop scaling relationships to predict contaminant release, transport, and attenuation in the field; these outcomes will be integrated by Ekati into closure planning and cover design.