Grant: Collaborative Research and Development Grants

The growth of the diamond mining industry in Canada has brought significant economic benefits to the Northwest Territories, with three operating mines producing approximately 13% of the world's diamonds in 2008. In addition, several base metal projects are in the planning stages or are set for production in the Territories. The long-term benefit of these mining activities to northern communities will depend on careful environmental management. The recovery of ore in mining operations involves the removal of waste rock, which is stockpiled in large piles. When exposed to oxygen in the air, minerals in the waste rock oxidize and may generate acid mine drainage (AMD) that can be damaging to aquatic environments. Little is known about the environmental implications of storing waste rock stockpiles in permafrost regions, such as northern Canada. At the Diavik Diamond Mine, located 300 km northeast of Yellowknife, Northwest Territories, scientists from universities across Canada have teamed up to investigate the processes that control AMD in this permafrost environment. The research program at the Diavik mine has involved the construction of three 15 m high waste rock piles fitted with instruments to measure temperature, moisture content, water chemistry, gas concentrations, air permeability, and thermal conductivity. The information gained from this study will be used to understand the physical and geochemical processes that control the generation of AMD. This knowledge will assist mining companies in evaluating their current waste rock pile designs for long-term protection of the environment, and will aid in environmental assessment and mine planning for those projects in the early stages of development. The results of this study can also be used to assess the effect of climate change on waste rock disposal systems. The information gained will have particular relevance to mining activities in northern regions of Canada and the world. Aspects of the study are also applicable to temperate climates, and thus will have broader relevance.