B.C. judge orders limit in tailings dam deposits at Mount Polley mine

Contents from a tailings pond is pictured going into Quesnel Lake near the town of Likely, B.C., on August, 5, 2014. It's been about a decade since millions of cubic metres of mine waste gushed from a tailings pond at the Mount Polley mine in British Columbia's Interior. THE CANADIAN PRESS/Jonathan Hayward

The Supreme Court in British Columbia has ordered that the Mount Polley mine limit the tailings it can deposit into its storage facility while a First Nation challenges an addition to the dam in court.

The court’s decision issued Thursday orders the Mount Polley Mining Corp. not to deposit mine tailings that would require the raising of the storage facility dam by four meters until July 1.

Justice Gary Weatherill has scheduled a four-day hearing starting June 24 for the case as part of the court’s order on Thursday.

The B.C. government said it approved the addition of four metres on the dam to safely manage the spring runoff, adding that the project was reviewed by technical experts and in consultation with First Nations.

In a statement, Imperial Metals — Mount Polley’s parent company — said “normal operations of the mine and construction of a four-metre raise of the tailings storage facility will continue.”

“Mount Polley Mining Corporation, Imperial’s wholly-owned subsidiary, made clear at the hearing that although it continues with previously permitted use of the tailings storage facility, it did not anticipate needing to use the four-metre raise currently under construction until July 1, 2025 at the earliest,” the statement said.

A similar storage site at the mine in B.C.’s Cariboo region collapsed in August 2014, spilling about 25 million cubic metres of water and tailings into nearby waterways in one of the worst environmental disasters in B.C.

The ruling arrived after the Xatsull First Nation applied for an emergency injunction to stop the four-metre addition on the tailings dam while the court hears a judicial review of the construction’s approval by the provincial government.

The Xatsull First Nation said it welcomes the court’s decision, and will argue during the hearing in June that the limiting of tailing deposits at Mount Polley should remain in place until the judicial review has been decided.

It said the order from court will help ensure no further harm from increased levels of tailings deposits will be done until the judicial review is heard.

“Under the circumstances, and especially given the devastating history of Mount Polley, Xatsull welcomes the court’s determination,” the statement said.

The nation said the province is at risk of losing the progress that it has made toward reconciliation because it is allowing the tailings storage facility to be raised without the legally required environmental assessment and without obtaining Xatsull’s consent.

The Xatsull also urged Imperial Metals, Mount Polley and the province to “act in good faith” in strengthening their relationship with the nation in a way that “honours Xatsull’s role in the territory now and for generations to come.”

In its response to the Xatsull’s petition to pause the dam construction, the province said its ministers for mining and environment did properly consult the Xatsull on the project before approval was given.

“The consultation with Xatsull undertaken by the province included engagement with the Environmental Assessment Office and with the Major Mines Office of the Ministry of Mining and Critical Minerals … and upheld honour of the Crown,” its response said.

“The Ministers’ decision reflects the substantive consideration of Xatsull’s concerns and legal position in relation to the interpretation of the statutory instruments, the process for authorizing the tailings storage facility raise, and the substantive concerns advanced concerning a heighted environmental risk from the tailings storage facility raise.”

The province had also argued that Mount Polley has a valid environmental assessment certificate for raising the dam.

“Even in the (Xatsull’s) materials, there is no evidence that the design of the tailings storage facility raise is not safe, nor that irreparable harm will result from its construction,” the provincial response said.

In its legal response, the Mount Polley Mining Corp. voiced support for the hearing to be held at the end of June for “allowing Xatsull’s concerns to be heard in full on their merits.”

“Construction of the tailings storage facility raise is well underway,” Mount Polley’s response said. “It also requires the entire construction season to complete, and even a short delay risks that the work is not complete this season.”

The company also said stopping operations at the mine would have resulted in Mount Polley having to lay off about 255 unionized workers and the loss of “tens of millions of dollars of business” to the mine’s various suppliers and vendors ranging from corporate contractors to small family-run businesses.

This report by Chuck Chiang, The Canadian Press, was first published May 9, 2025.