Resume/ Abstract
Many mine sites are exploring shifting their tailings management strategies from conventional tailing storage to filtered tailings (sometimes referred to as dry stack tailings). Filtered tailings storage facilities can reduce geotechnical stability risk, but because the material is unsaturated, there is often an assumed increased risk of metal leaching/acid rock drainage (ML/ARD) from sulfidic tailings. When forecasting water quality, in some instances, the entire sulfidic (reactive) filtered tailings profile is assumed to become oxic, adding inherent conservatism into the design. To more realistically conceptualize the extent of tailings oxidation in filtered tailing storage facility, reactive transport models of Potentially Acid Generating (PAG) sulfidic tailing were simulated. Through several model scenarios, we demonstrate the mechanistic process controlling oxygen ingress and pyrite weathering over time to simulate seepage water quality from the same materials under various storage facility designs. Initial models demonstrate that oxygen ingress maybe limited to the top several meters of the stockpile for the first few decades, while poor quality basal seepage production may not be observed for many more decades. In all tailings storage designs, management of runoff during Operations is key. Models like these can be used for site-specific sensitivity evaluation to understand the ML/ARD risk of reactive filtered tailing management strategies in a variety of climate conditions and storage timeframes.