Pabst, Thomas (École Polytechnique de Montréal)

Purpose

One of the most critical issues for the mining industry remains the management and safe disposal of the important quantities of solid wastes (mine tailings and waste rocks) produced during the operations. These materials often contain sulfides which can oxidize upon contact with oxygen (air) and water, producing acidic waters with high concentrations of sulfates and heavy metals (known as acid mine drainage, AMD). The proposed research program aims at developing tools and techniques for the disposal of mining wastes in open pits in order to reduce the environmental impact and footprint of disposal sites. This approach is used in a few mining projects but further research is required to fully optimize the technique. The assumptions are that in-pit disposal can be used to limit the risk for AMD generation, improve the overall long term geochemical and geotechnical stability of the disposed materials, stabilize the walls of the pit, reduce the need for building new impoundments or waste rock piles, and improve the aesthetics of the sites. There are, however, several challenges to the method, particularly regarding the geochemical stability of the disposed wastes, the control of water flow and exchanges with the surrounding environment, and the operational aspects of the disposal itself.