July 2016 Geochemical characterization and speciation of tailings at Tundra Mine, Northwest Territories, Canada

Two phases of mining and milling at the Tundra Mine, in 1960s and 1980s, resulted in the accumulation of approximately 240,000 m3 of arsenic-rich tailings solids. Seepage from the tailings ponds has resulted in contamination of the downstream environment, however, due to the presence of mineralized bedrock, naturally occurring metal(loid)s may also contribute to increased concentrations in sediment and surface waters. Cores were collected from the tailings to aid in differentiating between mining contamination and naturally occurring metal-bearing minerals in the lake environments downstream of the former mine site. Microanalytical techniques, including X-Ray Absorption Near Edge Structure (XANES) and Mineral Liberation Analysis, will be used to characterize the mineral species present in the tailings to allow for accurate assessment of the downstream extents of historical mining impacts.1960年代与1980年代，苔原矿场（Tundra Mine）先后开展两期采矿与选矿作业，累计堆积约24万立方米的富砷尾矿固体。尾矿库渗滤液已造成下游环境污染；但由于区域内赋存矿化基岩，天然存在的金属与类金属也可能推高沉积物及地表水的污染物浓度。为辅助区分原矿场下游湖泊环境中采矿活动引发的污染与天然含金属矿物的影响，研究人员从尾矿中采集了芯样。本研究将采用X射线吸收近边结构（X-Ray Absorption Near Edge Structure，XANES）、矿物解离分析（Mineral Liberation Analysis）等微分析技术，对尾矿中的矿物种类进行表征，从而精准评估历史采矿活动对下游区域的影响波及范围。