The ministers of Environment and Parks, Tamara Davidson, and Mining and Critical Minerals, Jagrup Brar, have issued a consent order to Mount Polley Mining Corp. to raise the tailings pond dam of the Mt. Polley Copper-Gold Mine by four metres.

The ministers’ decision was informed by an Environmental Assessment Office (EAO) review, conducted in collaboration with the Mining and Critical Minerals Major Mines Office, which also must make a decision whether to approve the increased height under the Mines Act.

The ministers agreed with the EAO’s conclusions that increasing the total height to 64 metres from the current 60 metres at the already-developed mine site is not likely to result in new or significant impacts compared to current approved operations. The ministers are satisfied that safety issues have been assessed thoroughly through technical reviews carried out by an external third-party geotechnical engineer and geotechnical engineering experts in the Major Mines Office.

On Aug. 4, 2014, a tailings pond dam breach caused mine waste, water and construction materials to flow into Polley Lake, Hazeltine Creek and Quesnel Lake causing widespread and long-lasting environmental damage and serious impacts.

The Province subsequently implemented all recommendations from two separate investigations in 2015 by an independent expert engineering panel and the chief inspector of mines. These led to significant changes in 2016 to how tailings ponds are regulated under the Health, Safety and Reclamation Code for Mines in B.C., which was further updated in 2024. The proposed dam height increase at the Mt. Polley Mine meets or exceeds all regulatory requirements in the current code.

The Major Mines Office led the technical review of the potential impacts and associated mitigation measures of the proposed increase in dam height, as an amendment to the Mines Act permit for the mine also is required. The Major Mines Office and the Environmental Assessment Office reviews both included consultation with Williams Lake First Nation and Xatśūll First Nation.

A decision by the Major Mines Office's statutory decision-maker to approve the proposed Mines Act permit amendment to raise the dam by four metres was also issued on Thursday, March 27, 2025.

Mount Polley Mining Corp. has applied to expand mining and make other changes at the site over the course of the next few years. Due to time constraints presented by impacts to mining operations and managing higher water volumes during the spring melt, the Environmental Assessment Office and Major Mines Office reviewed the interim four-metre height increase to continue existing approved operations separately from the expansion request. The proposed expansion to the mine is still being assessed by the EAO. No decisions have been made on whether or not to approve the expansion to allow the mine to continue operating past 2031.

The Mt. Polley mine was approved by the provincial government in 1992. Under its certificate, which remains in effect under the Environmental Assessment Act, the operator must obtain the written consent of the ministers prior to any material alterations to the Mt. Polley mine from what was previously approved.

The Mt. Polley Mine is located in the Cariboo region of central British Columbia, approximately 56 kilometres northeast of Williams Lake. It began operations in 1997. Operations were approved to resume under the Mines Act permit in 2016, after they had been paused due to the 2014 dam breach.

Learn More:

For ministers’ reasons for their decision, visit: https://www.projects.eao.gov.bc.ca/api/public/document/67e5787dc102740022549973/download/ReasonsForDecision_Consent_Material_Alteration_TSFRaise_FINAL.pdf

EAO’s recommendation regarding consent for material alteration: https://projects.eao.gov.bc.ca/api/public/document/67e578d7c10274002254997e/download/Report_Consent_Material_Alteration_TSFRaise_Final.pdf