The Sherridon orphan mine site is adjacent to the communities of Cold Lake and Sherridon in northwestern Manitoba, approximately 121 kilometers northeast of the community of Flin Flon. The Sherridon copper and 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.

Tetra Tech’s scope included the following:

  • Assessing and identifying all safety, health, and environmental concerns identified in the risk assessment study
  • Developing site-specific, cost-effective rehabilitation strategies and implementation plans to mitigate these concerns
  • Developing a complete rehabilitation scope of work schedule and timeline
  • Developing a cost estimate for obtaining funding for the implementation plan
  • Developing a regular inspection, maintenance, and monitoring program to comply with all relevant provincial and federal acts and regulations
  • Detailed design of the selected alternatives
  • Construction management

The rehabilitation includes treating and covering Camp Lake and relocating or 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.

Tetra Tech developed detailed designs of all project components, including water diversion and management works, water treatment and tailings neutralization requirements.


Jim Rondeau, Minister of Science, Technology, Energy, and Mines, 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.”