Oxygen-18 and Deuterium Fingerprinting of Tailings Seepage at the Sullivan Mine

Stable isotopes of water, ¹⁸O and ²H, were used to fingerprint and quantify the origin and percentage of mixing between tailings pond effluent, seepage collection waters, and background waters at the Sullivan Mill Site, which is located in Kimberley, British Columbia, Canada. The old iron and siliceous ponds are covered by a layer of permeable float rock, which allows meteoric waters to directly infiltrate without undergoing evaporation. In contrast, the east gypsum pond is covered with a layer of till and vegetation, which causes meteoric waters to pond and subsequently be subjected to evaporative processes. The different evaporative environments result in distinctly different isotopic compositions for the waters collected from these sources. The difference in surface cover was used advantageously to identify particular isotopic ratios for the different tailings sources. Water collected from the east gypsum pond is relatively enriched in the heavier isotopes (δ¹⁸O and δ²H), whereas water collected from various locations in the siliceous and old iron pond are relatively depleted in δ¹⁸O and δ²H. The various seepage collection waters were observed to plot at intermediate positions, corresponding either to the old iron pond mixing line, the gypsum pond evaporation line, or somewhere between the two.