Canadian Large Projects

Mount Polley

  • The most current regulatory information regarding the Mount Polley Mine may be found here


  • On August 4, 2014, a tailings pond breach occurred at Mount Polley Mine in south-central B.C., near the town of Likely. The breach released approximately 17 million cubic meters of effluent water and 8 million cubic meters of tailings material into Hazeltine Creek, Polley Lake and Quesnel Lake. The affected water bodies are in the upper Fraser River watershed, which does not drain into Alaska waters. However, the Fraser River supports fish populations that are important to Alaska commercial fisheries.


  • The B.C. Ministry of Environment (MoE) is the lead agency responding to the breach while the B.C. Conservation Office Service (COS) is the lead agency investigating the cause of the incident.


  • Mount Polley Post-Event Environmental Impact Assessment Summary Report

  • Following the failure of the Mount Polley tailings storage dam, the Chief Inspector of Mines ordered that: (1) The deadline for 2014 Dam Safety Inspections (DSIs) for all dams in B.C. be accelerated from March 31, 2015 to December 1, 2014; (2) Those inspections be reviewed by an independent, qualified, third-party professional engineer from a firm not associated with the tailings storage facility; (3) The dam’s consequence classification be reviewed by a third party; and, (4) For dams with a consequence classification of high, very high or extreme that the Emergency Preparedness and Response Plans (EPRP) be reviewed, tested and updated as required.

    The dam inspection reports and other relevant information for all B.C. mines may be found here

    The B.C. Chief Inspector of Mines’ Investigation Report on Mount Polley may be found here.