Environment and Parks
Summary
- Provincial ministers have approved a planned tailings dam height increase as part of the approved expansion of the Mt. Polley copper and gold mine that will enable production to continue until 2033
- Environmental and safety issues were thoroughly assessed by technical experts through both the Environmental Assessment Office and the Major Mines Office, which concluded that with permit conditions, the changes are unlikely to result in significant additional impacts compared to existing mine operations
- The mine expansion protects 430 direct and 700 indirect jobs for an additional eight years
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The ministers of Environment and Parks, Tamara Davidson, and Mining and Critical Minerals, Jagrup Brar, have issued a consent order to Mount Polley Mining Corporation for a material alteration to the Mt. Polley Copper/Gold mine to raise the height of the tailings storage facility by 13 metres, bringing the dam height to 77 metres.
This dam height increase was proposed as part of a series of changes the company has been planning to support its Springer Pit expansion, which was approved in 2025. The expansion will mean the continuation of 430 direct jobs at the mine and 700 indirect jobs, along with a capital investment of $130 million. The existing mine contributes approximately $245 million to B.C.’s GDP and supports $190 million per year in contracts with B.C. suppliers.
The ministers’ decision was informed by a comprehensive review over the past seven months conducted by the Environmental Assessment Office (EAO), in collaboration with the Ministry of Mining and Critical Mineral’s Major Mines Office. The decision is pending on permit amendments under the Mines Act, which are also required for the dam height increase to proceed.
The overall existing permitted mine area for Mt. Polley remains unchanged. Raising the dam will increase the footprint of the tailings storage facility (or tailings pond) by approximately 28 hectares, including the added buttressed materials to improve dam stability. Other minor changes to the mine site include access roads, as well as location of powerlines and hauling roads.
In their reasons for decision, the ministers agreed with the EAO’s conclusions that the proposed changes are not likely to result in significant new impacts compared to existing approved operations. They noted that impacts would be effectively managed through mitigation measures required by permitting, which must meet or exceed all regulatory requirements in the current mine regulations. Ministers are satisfied that environmental and safety issues have been thoroughly assessed by technical experts.
The EAO consulted and sought consensus with Williams Lake First Nation and Xatśūll First Nation as part of its assessment of the change. The Nations participated in the Mine Review Committee and provided input about the draft report and proposed permit conditions.
The mine’s environmental assessment certificate requires Mount Polley Mining Corporation to obtain the written consent of the ministers of Environment and Parks and Mining and Critical Minerals prior to any material alterations to the mine from what was previously approved.
In April 2025, the ministers approved an increase to the height of the tailings dam by four metres, as an interim step to manage spring flows, while additional changes to extend the mine life were being planned. In August 2025, the ministers approved the Springer Pit expansion, extending the mine’s operating life to 2033. The newly approved dam height increase supports ore processing for the Springer Pit expansion and is the company’s final planned alteration associated with the expansion at this time.
Compliance and enforcement officials from the ministries of Mining and Critical Minerals and Environment and Parks will continue to monitor the Mt. Polley mine project to ensure all requirements are met. Compliance is monitored through regular site inspections, ongoing geotechnical reviews and annual independent dam safety inspections, as required by law.
Quick Facts:
- The Mt. Polley Copper/Gold mine is located in the Cariboo region of central British Columbia, approximately 56 kilometres northeast of Williams Lake.
- The Mt. Polley mine was originally approved by the provincial government in 1992. The open-pit copper and gold mine began operations in 1997.
- After a significant tailings pond dam breach at the Mt. Polley mine in 2014, the Province substantially updated B.C.’s Health, Safety and Reclamation Code for Mines to strengthen mine regulation.
- The Mt. Polley tailings dam had to undergo design changes to comply with the new code requirements before it could reopen in 2016.
- Further updates to strengthen the code were made in 2024, and all alterations to the project must meet all of these technical, engineering and safety requirements.
Learn More:
- For ministers’ reasons for decision, visit:
https://www.projects.eao.gov.bc.ca/api/public/document/6a4fe33fb28e7c957c5a2ff3/download/Mt_Polley_987mRaise_Reasons%20for%20Decision_Signed.pdf - For EAO’s recommendation regarding consent for material alteration, visit:
https://www.projects.eao.gov.bc.ca/api/public/document/6a4fcc1ab0a6759581da83ff/download/1-%20Mt_Polley_EAO_Recommendation_Report.pdf
