The influence of mining on hydrology and solute transport in the Elk Valley, British Columbia, Canada

Previous research has established that surface mining affects downstream water quality. However, there remains limited information and understanding about the interaction of hydrology and geochemistry in surface mined areas. This paper presents an analysis of a multi-year dataset of geochemistry across a gradient of surface mining in an alpine environment. This work formed part of an R&D program examining the influence of mining on hydrological and water quality responses in the Elk Valley, British Columbia, Canada, aimed at informing effective management responses. Results indicate that water from waste rock dumps has a consistent ionic profile that is distinct from reference catchments. The export of weathering solutes did increase with the degree of mine affected area, and was consistently limited more strongly by transport capacity than by supply. Geographical location of waste rock within the catchment (headwaters or outlet) did not affect chemical concentrations or the timing with which chemically distinct waters reported to basin outlets. The dominance of transport capacity over source as limiting to solute export highlights the importance of limiting water input to waste rock piles. However, results strongly suggest that lateral water inputs do not mobilize significant amounts of weathering solutes.