Mine tailings generating acid mine drainage (AMD) can be problematic for the environment. AMD is produced when tailings containing sulphide minerals are exposed to oxygen and water, which then oxidise to release acidity and dissolved metals in the environment.
In temperate climates, oxygen barrier covers are often constructed on tailings storage facilities to limit the influx of oxygen to the tailings and prevent the production of AMD. However, low pH and dissolved iron on abandoned mine sites can extend the AMD production even without oxygen due to the action of ferric iron (Fe3+).
The main objective of this project is to have a better understanding of the hydrogeochemical behaviour of the elevated water table technique combined with a monolayer cover when indirect oxidation reactions (without oxygen) of sulphides occur.
To do so, an extensive investigation is performed on the Manitou abandoned mine site tailings storage facility no. 2 (TSF 2). First, field monitoring is used to gather data related to the TSF reclamation’s effectiveness. Secondly, numerical modeling analyses are used to understand the hydrogeological behaviour of the site, which is directly related to the reclamation strategy used at the Manitou site. Finally, a better integration of the indirect tailings oxidation in an improved numerical code will help predict the long term environmental behaviour of abandoned mine sites.