British Columbia

Mount Polley mine agrees to limit tailings dam deposits while court challenge heard

The Mount Polley mine has agreed in a B.C. Supreme Court to limit the tailings it can deposit into its storage facility, while the Xatsull First Nation challenges an addition to the dam.

The court did not order a pause on construction of the tailings storage facility

A woman wearing sunglasses stands at a podium with a microphone. She's smiling. There are two smiling women, out of focus, in the background.
Chief Rhonda Phillips of the Xatsull First Nation stands outside of the law courts after announcing they have filed a judicial review with the B.C. Supreme Court in Vancouver on April 15. (Ben Nelms/CBC)

The B.C. Supreme Court will hold a four-day hearing next month to address a First Nations challenge to a proposed addition to a storage facility for tailings at the Mount Polley mine.

The Mount Polley Mining Corp. has agreed 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 the hearing to begin 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 read.

A similar storage site at the mine in B.C.'s Cariboo region, about 370 kilometres northeast of Vancouver, 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 Xatsull First Nation has applied for an emergency injunction to stop a four-metre addition on the tailings dam while the court hears a judicial review of the construction's approval by the provincial government. 

The First Nation said it will argue during the hearing next month that there should be a pause on tailing deposits until that review is complete.

It said the order from court Thursday 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 First Nation said in a statement. 

Dispute over consultation process

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's parent company, 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."

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

In its response to the Xatsull's legal challenge, 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 heightened 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 and that construction on the project should not be paused during the legal challenge.

"Even in [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. also argued against pausing construction on the project, voicing 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 could result 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.

Corrections

  • A previous version of this story incorrectly stated the court had issued an injunction in the case, and that the storage facility could no longer be used. In fact, it can be used, but not above the dam's additional four-metre height.
    May 09, 2025 7:47 PM EDT