The British Columbia government has granted Imperial Metals permission to increase the height of the tailings dam at its Mount Polley copper and gold mine northeast of Williams Lake, the same mine that suffered a catastrophic dam failure in 2014. The approval, issued on Thursday by Environment Minister Tamara Davidson and Mining Minister Jagrup Brar, allows the company to raise the dam by 13 metres to a total height of 77 metres as part of an expansion that will extend the mine's life by eight years.
Regulatory approval and environmental assessment
The consent order was based on the Environmental Assessment Office's conclusion that raising the dam height is “not likely to result in significant new impacts compared to existing approved operations,” according to a government news release. The increased height will expand the surface area of the tailings pond by about 28 hectares, supporting the company's Springer Pit expansion, which was approved by the province in 2025.
The Mount Polley mine, located 56 km northeast of Williams Lake in B.C.'s Cariboo Chilcotin region, began operations in 1997, with a hiatus between 2001 and 2004 due to low copper prices. Operations were suspended again after the dam collapse on August 4, 2014, with a partial reopening in 2015 and full resumption in 2016.
Economic impact and job preservation
The latest expansion requires an additional investment of $130 million and is intended to maintain the mine's 430 direct jobs and 700 indirect jobs until its expected closure in 2033. According to the province, the existing mine contributes $245 million to B.C.'s gross domestic product and spends about $190 million per year with B.C. suppliers.
First Nation opposition and legal challenges
The Xatśūll First Nation, whose traditional territory includes the Mount Polley mine, have opposed the approval, citing risks of another dam failure and what they have deemed as information gaps in the Mount Polley Mining Corp.'s application. A spokesperson from the Xatśūll was not available for comment Friday, but in correspondence with the Environmental Assessment Office, the First Nation characterized the regulatory process as an “approve now, study later” effort.
In 2025, the Xatśūll filed a petition seeking to set aside approval of permits related to the Mount Polley expansion. That action was dismissed by B.C. Supreme Court Justice Michael Tammen in August 2025. The First Nation has appealed that decision, and Imperial Metals' latest financial report noted that the Xatśūll are not seeking an injunction in the case. A hearing on the matter is expected October 22-23 this year.
In the published reasons for their decision, Davidson and Brar said their view is that the Environmental Assessment Office “made reasonable efforts to support the reconciliation purpose” of the applicable legislation by seeking consensus with First Nations.
