Effect of climate change on the performance of a monolayer cover combined with an elevated water table to prevent acid mine drainage

ABSTRACT: The chemical reaction of sulfides contained in mine tailings with water and oxygen can generate acid mine drainage (AMD). Reclamation methods must be considered, such as monolayer cover combined with elevated water table (EWT). This method consists in maintaining the tailings close to saturation, which limits the flow of oxygen and AMD generation. The performance of the technique is strongly related to precipitations that can influence the water table position within the tailings. In the context of climate change, the evolution of the future precipitation regime must be considered to ensure the efficiency of the reclamation over the long term. A monolayer cover combined with a EWT is considered to reclaim the Doyon-Westwood (Québec) mine site tailing ponds. Experimental cells installed on the site since 2015 were simulated numerically to evaluate the performance of the method. Average annual weather conditions up to year 2100 and extreme drought events were then incorporated into the model.