The B.C. government has issued a consent order to Mount Polley Mining Corp. to raise a tailings pond dam by four metres at the site of one of the largest environmental disasters in provincial history.
The dam at the Mount Polley gold and copper mine collapsed on Aug. 4, 2014, sending 25 million cubic metres of mine waste, water and construction materials downriver. Polley Lake, Hazeltine Creek and Quesnel Lake all faced widespread and long-lasting environmental damages in what would become North America’s biggest such failure on record.
A number of regulatory actions followed. And in December 2024, 15 federal Fisheries Act charges were laid against the mine's parent company, Imperial Metals Corp., and two other firms over the collapse of the tailings pond dam, which occurred 56 kilometres northeast of Williams Lake, B.C.
The latest consent order from Environment and Parks Minister Tamara Davidson and Mining and Critical Minerals Minister Jagrup Brar will raise the dam to 64 metres from its current 60 metres.
In a press release Thursday, the ministers said they were “satisfied” that safety issues were properly assessed through a third-party engineer and experts at the Major Mines Office. That same office approved the proposed permit amendment to raise the dam on Thursday.
“We recognize that there are significant concerns around this mine. Since 2016, the mine has been operating under significantly stronger environmental standards,” said the ministers in a joint statement.
“What happened in 2014 can never happen again. Our strong requirements to protecting the environment are non-negotiable.”
The mine first opened in 1997 and reopened in 2016 following the dam breach.
The province says Mount Polley Mining Corp. has applied to expand mining over the coming years. It said the proposed expansion to the mine is still being assessed by the Environmental Assessment Office.
“No decisions have been made on whether or not to approve the expansion to allow the mine to continue operating past 2031,” noted the province in its release Thursday.
Nikki Skuce, who heads the BC Mining Law Reform Network, said the decision to expand operations at the Mount Polley dam is “risky.”
“They went too far. Some changes have been made since the disaster. We’d argue not enough for safety to be put first,” she said. “To just keep adding volume, I’m not sure the province has the regulatory guarantees that this will never happen again.”
In 2022, a report commissioned by Skuce’s organization found nearly half of the province’s existing mine sites with tailings storage facilities are likely to have high, very high or extreme consequences in the event of dam failure.
Among sites currently inactive or undergoing maintenance, 46 per cent were found to have the potential to cause loss of human life, environmental fallout, or significant economic damage. For currently operational or proposed tailings dams, that potential jumped to 83 per cent, found the report.
The decision over the Mount Polley dam also comes a day after the release of an investigative report from SkeenaWild Conservation Trust that claimed a lack of government oversight and regulations have led to contamination and risked tailings dam safety at B.C.'s Red Chris Mine.
Located 450 kilometres north of Smithers, the mine began operating in 2015. And in 2023, its owners began pursuing an expansion of its operations. The B.C. government included the Red Chris Mine expansion in a list of 18 project applications that would be fast-tracked in response to U.S. tariffs.
The SkeenaWild report, which was largely based on documents accessed through the Freedom of Information Act, says the mine has failed to develop effective water treatment plans to protect downstream environments. Selenium concentrations were already found to be elevated at two lakes downstream, and an unexpected lack of water has complicated impacts to aquatic species.
The Red Chris Mine's tailings dam, meanwhile, was found to use the same foundation materials associated with the Mount Polley dam failure. Its construction has also “repeatedly failed” to meet targets, increasing the likelihood of failure, the report said.
If only half of the stored water were to burst through a failed Red Chris dam, the mine waste released from its storage pond would be more than four times what flowed downriver from Mount Polley in 2014, the report found.
SkeenaWild concluded that dam failure modelling and emergency planning faced “multiple shortcomings” — increasing risks to people and the environment downstream of the mine.
Dam construction at the Red Chris Mine was overseen by Imperial Metals Corp. and the engineering firm AMEC. Both oversaw the construction of the Mount Polley dam before it failed.
— With files from the Canadian Press
