Control of Leachate Contamination from Mine Wastes Through an Appropriate Operating Practice

Mine wastes pose a significant environmental risk. Natural waters in areas that have a long history of mining tend to be polluted by release of metals resulting in environmental issues such as acid mine drainage. Interventions to mitigate such risks can be part of the operating practice and need not be assigned to the post-mining era. In this study, the leachability potential of slag at a smelter slag dump of a former mine site was assessed using the modified Ontario leachate extraction procedure (MOLEP) and other regulatory leachate quality criteria. Results showed that the release of contaminants (Cu, Co, Pb, Zn, As, Fe and Cd) can be maintained within industry-regulated standard limits mainly by adopting a smelter operating practice that produces a slag composition with adequate self-neutralising capacity.