British Columbia ministers have approved a height increase for the tailings dam at the Mount Polley mine, the site of a massive breach nearly 12 years ago.
The Mount Polley copper and gold mine is located in south-central B.C., about 56 kilometres northeast of Williams Lake.
Environment and Parks Minister Tamara Davidson and Mining and Critical Minerals Minister Jagrup Brar approved the plan to increase the height of the tailings storage facility by 13 metres to support ore processing for the mine’s Springer Pit expansion.
A statement on the ministers’ decision said it was informed by a comprehensive review conducted by the Environmental Assessment Office over the past seven months.
It said the ministers agreed with the EAO’s finding that the proposed changes are not likely to result in significant new impacts compared to the existing operations.
Permit amendments under the Mines Act are still required before the project can go ahead.
A previous four-metre increase to the height of the tailings dam was approved in April 2025 as an interim step to manage spring flows.
The Springer Pit expansion, approved last August, is expected to extend the mine’s operating life to 2033.
One of Canada’s worst mining disasters happened in the early morning hours of August 4, 2014, when a tailings dam breach at the Mount Polley site sent about 25 million cubic metres of water and materials into Quesnel Lake and other nearby waterways.
Nearby First Nations have said the breach had a major impact on access to local fish stocks and caused lasting damage to salmon habitat in the area.
The Xatśūll First Nation opposed mine owner Imperial Metals’ bid to raise the height of the dam, arguing the province didn’t follow the required environmental assessment process before authorizing the project.
The B.C. Supreme Court rejected the legal challenge last year.
The province said the EAO consulted and sought consensus with Williams Lake First Nation and Xatśūll First Nation as part of its assessment of the change.
The province also said it has substantially updated mine safety regulations since the 2014 disaster.
