Elliot Lake, Ontario uranium mines a legacy perpetual care case study

Abstract

Twelve uranium mines were opened in the vicinity of Elliot Lake, Ontario Canada between 1955 and 1958. In the early 1960s, eight of these mines were acquired and amalgamated to form Rio Algom Limited (RAL), now a subsidiary of BHP. During the 1960s only two mines were operational with remaining mines placed in care and maintenance. Two mines were reactivated and one expanded in the late 1970s and subsequently closed between 1990 and 1996. This construction and operating history produced eight tailings management areas with 102 Mt of tailings (range of 0.08 to 46 Mt), covering 920 ha (range of 13 ha to 400 ha) and various cover configurations (water, vegetated and combinations thereof). As part of the federal environmental assessment review process for closure, all facilities were subject to cost-benefit analysis to select final closure configuration. Closure was implemented at all facilities between 1992 and 2000 to meet then best practice for nuclear waste facilities. This paper will provide a 20-year post-closure perspective of water management, water treatment and watershed performance and key learnings for these perpetual care facilities.