McKeown, M., D. Christensen, S. Mueller, P. Weber, and M. O'Kane.
2018 Northern Latitudes Mining Reclamation Workshop, September 10-13, Whitehorse and Carcross, Yukon. 27 slides, 2018

The Boliden Aitik Mine is located near Gallivare, northern Sweden. Evaluation of closure plan development for water quality emanating as basal and toe seepage from the waste rock storage facilities (WRSFs) was a key input for evaluating risk in terms of managing impacts on the aquatic receiving environment for the site as a whole. The evaluation used a holistic approach that included consideration of site-specific hydrogeology, WRSF geochemistry, and unsaturated zone hydrology, as well as cover system and landform design and implementation. Numerical modeling was used to estimate long-term oxygen ingress and net percolation rates for closure conditions based on inputs obtained from seven yrs of in situ cover system monitoring and field testing. The overarching findings of the study were that water quality from the WRSFs will improve over time as the closure cover system limits oxygen to the underlying waste rock, soluble stored load is flushed, and sparingly soluble load is neutralized by available alkalinity. As stored acidity is flushed, the model predicts that pH will increase and acidity loads will decrease, resulting in circumneutral basal and toe seepage with associated low dissolved metals concentration. This condition is characterized as occurring within ~50 yrs after implementation of closure measures.
Slides: https://www.yukonminers.org/index.php/presentations/58-mckeown-mike-forecasting-long-term-water-quality-swedish-mine/file
Longer abstract: https://www.yukonminers.org/index.php/abstracts-and-biographies/34-mckeown-matt/file