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.