The Sherridon orphan mine site is adjacent to the communities of Cold Lake and Sherridon in northwestern Manitoba, approximately 121 km northeast of the community of Flin Flon. The Sherridon copper/zinc mine operated at this location between 1931 and 1951.

Working for Manitoba Science, Technology, Energy, and Mines, Tetra Tech developed a site specific, cost effective rehabilitation implementation plan to mitigate safety, health and environmental concerns at the mine site.

The tailings deposit from the mine covers approximately 47 hectares (116 acres) and is comprised of approximately 7.4 million tons of acid-generating waste located adjacent to Camp Lake. The largest part of the remediation work is relocating and neutralizing these tailings. This has been solved by raising the level of adjacent lakes and using them to flood the tailings.

The project is moving into detailed design for remediation. Tetra Tech’s scope included:

• Assessed and identified all safety, health, and environmental concerns identified in the Risk Assessment Study
• Developed site specific, cost effective rehabilitation strategies and implementation plans to mitigate these concerns
• Developed a complete rehabilitation scope of work schedule and timeline
• Developed a cost estimate for obtaining funding for the implementation plan
• Developed a regular inspection, maintenance, and monitoring program to be in compliance with all relevant Provincial and Federal Acts and Regulations

The rehabilitation includes treating and covering Camp Lake and relocating/neutralizing tailings with flooding. This effort will reduce contaminant flux to Camp Lake, improve water quality in nearby Kississing Lake, control wind erosion of tailings solids, and improve aesthetics at the site.

Highlight: The Minister of Science, Technology, Energy, and Mines Jim Rondeau said that the rehabilitation work, “brings direct economic benefit to nearby communities and First Nations, and the long-term gains of clean air, water, and land.”