Marking 20 years
of bold journalism,
reader supported.
Labour + Industry

Will BC Let Mount Polley Mine Keep Pumping Waste into Quesnel Lake?

Eight years after a tailings pond disaster, critics say Imperial Metals should have come up with better waste plan by now and warn of risks.

Amanda Follett Hosgood 3 Aug

Amanda Follett Hosgood is The Tyee’s northern B.C. reporter. She lives in Wet’suwet’en territory. Find her on Twitter @amandajfollett.

Eight years after a mine’s tailings dam collapsed and sent a torrent of toxic wastewater into a central B.C. lake, the company responsible is ramping up operations as it awaits a provincial permit that would allow it to continue dumping waste into Quesnel Lake.

According to its spring quarterly report, Vancouver-based Imperial Metals had invested more than $20 million by March 31 into resuming operations at its Mount Polley Mine. The copper and gold mine 50 kilometres northeast of Williams Lake was shuttered in 2019.

It expects the mine to become fully operational this summer.

But the company is still awaiting the provincial government’s approval to extend its wastewater discharge permit, which expires Dec. 31. The permit, which the province describes as a “material alteration” to Mount Polley’s original environmental assessment certificate, allows the mine to discharge up to 52,000 cubic metres of treated mine waste every day into Quesnel Lake — the equivalent of 21 Olympic swimming pools.

While the company is also expected to investigate alternative ways of dealing with its wastewater, Doug Watt, a local resident and member of Concerned Citizens of Quesnel Lake, doesn’t believe that is happening.

“They’re using dilution of Quesnel Lake to meet the water quality guidelines rather than actually treating the water first,” Watt said. The current process deposits dissolved chemicals and heavy metals into the lake.

“They were required by the 2017 permit to do a bunch of work on alternative methods and actually set up lab tests and test sites,” he added. “They have not done that.”

Imperial Metals temporarily halted production at its Mount Polley mine after its tailings storage facility failed on Aug. 4, 2014, depositing nearly 25 million cubic metres of mine waste into the Fraser watershed — an amount roughly equal to the volume of water that flows over Niagara Falls every two-and-a-half hours.

The breach is considered amongst the worst tailings dam disasters in history.

Mount Polley returned to full operations in June 2016, six months after the province issued a temporary permit that allowed it to continue discharging into Hazeltine Creek, where waste would flow into a sediment pond and then by pipeline into Quesnel Lake, as it developed alternative methods for wastewater management.

The sediment pond was later replaced by a treatment facility designed to remove solid materials by filtering the wastewater through sand before it enters the lake.

The following year, Mount Polley received a new permit from the province, this time for the “discharge of mine effluent to Quesnel Lake during the remainder of operations.”

At the time, the mine’s life was expected to continue until this year. But the project’s projected life has continually been extended.

Mount Polley began operating in 1997 with an expected 14-year lifespan. It then closed for several years in the early 2000s. When the mine’s tailings dam breached in 2014, it had already reached its expected lifespan.

Following its initial reopening after the disaster, operations were again halted at the mine in 2019 due to low copper prices. Later that year, Imperial Metals acquired several new mineral claims adjacent to Mount Polley, further extending the mine’s projected lifetime.

In 2020, the company said it planned to operate the mine until 2031. More recently, Watt said, it has said it has 11 years’ worth of available ore.

He believes the mine plans to continue operating for “decades to come.”

“I’m pretty darn sure that they expect to continue finding ore. I mean, that’s what they’ve done forever,” he said.

Imperial Metals did not respond to interview requests or The Tyee’s emailed questions about the project’s projected lifespan, status of its discharge permit and long-term plans for water management.

A spokesperson for B.C.’s Ministry of Environment said in an email the province is considering two applications from the company.

The first, which it called a “major amendment,” is an application to continue discharging wastewater into Quesnel Lake beyond the end of this year. That application has not been formally received by the ministry, but a draft indicates the mine operator intends to request authorization to “discharge to Quesnel Lake for the extent of mine operations, i.e., until at least 2031,” the spokesperson said. A formal application is expected later this year, it said.

Because of the size and scope of that request, the ministry said it is also considering a second application for an “interim extension” that would allow Mount Polley to discharge into Quesnel Lake until 2025.

The authorizations don’t impact the mine’s current restart plans, the spokesperson added.

“While necessary for the mine to have a long-term water discharge authorization in place, neither of the two amendments will affect the mine restart, and the restart does not affect the amount of water that needs to be discharged as the mill recirculates water from the tailings impoundment,” the email said.

The mine notified the Ministry of Energy, Mines and Low Carbon Innovation of its intention to resume operations last August, the ministry added.

When asked whether the current permitting applications addressed long-term water management following the mine’s closure, the ministry said that the “information requirements for the major amendment application are currently being discussed” with Mount Polley.

Mines without closure plans ‘ticking time bombs’

Nikki Skuce, Northern Confluence director and co-chair of the BC Mining Law Reform network, which advocates for improved mining practices in the province, said the growing number of dormant tailings facilities presents a risk to British Columbians.

The organization, in collaboration with SkeenaWild Conservation Trust recently developed a map illustrating the number of tailings facilities in B.C. and their proximity to communities.

Skuce said there are 172 dams holding back tailings or other wet mine waste in the province and that 23 mines with tailings facilities are currently designated as being in “care and maintenance” — or indefinitely shuttered.

According to a report produced by an independent panel following the Mount Polley disaster, there is a significant statistical likelihood of one dam failure every decade if management of the facilities doesn’t improve.

The report suggests that an overall reduction in the number of tailings facilities would reduce that risk.

“The historic failure frequency provides clear evidence that past practices and technologies have failed to provide acceptable levels of tailings dam safety in the province,” the report said. “Equally clearly, then, both best practices and best available technology provide the dual cornerstones of an effective tailings dam safety strategy for the future.”

Skuce called the findings unacceptable and called on the industry to use methods such as backfilling, dry stack tailings and dewatering of tailings facilities after closure to reduce the risk.

“If we want to get on the path to zero failures, but we still want to have mining, we have to reduce the [tailings] inventory by half in British Columbia, and do best available technology and practices,” she said, calling mines left in care and maintenance without sufficient closure plans a “ticking time bomb.”

“Mount Polley was a total wake-up call and it generated some change for the better, but we still have these cumulative risks, we have growing volumes of tailings in British Columbia, and no plan to reduce them at the moment.”

As Mount Polley applies to the province to continue dumping mine waste into Quesnel Lake, a recently published research study shows that heavy metals from the disaster affected organisms in the lake years after the spill.

Researchers warn of potential risks to salmon

The paper, published in May, found that invertebrates from sites affected by the tailings breach showed elevated metal concentrations relative to those from non-affected areas four years after the disaster.

Lead researcher Gregory Pyle, a biology professor at the University of Lethbridge, said because the freshwater scuds and mayfly larvae that were collected in 2018 experience little movement and have short lifespans, they offer an area-specific, point-in-time glimpse into how organisms are being impacted years after the disaster.

“At the sites that were closest to where the contaminated tailings discharged into this site, we noted elevated concentrations of metals, and in particular copper, in these animals,” said Pyle, whose research examined both organisms collected from contaminated sites and those exposed to the sediment in a lab.

“If we allowed the organisms access to the materials of sites that were directly affected by the breach, we were finding that metals were accumulating in these animals to a greater degree than from materials at other sites and it was affecting their survival and growth,” he said.

That has two implications for larger organisms — such as salmon and other fish — in Quesnel Lake, he added.

Not only is there opportunity for fish to consume heavy metal-laden invertebrates, there’s a chance the food source won’t survive at all.

“We think this could lead to local extirpations, or local extinctions, of these animals from these systems, which would basically eliminate or at least reduce potential food sources for important fish species there,” Pyle said.

“The other implication is that because the metals are getting into these invertebrates, that provides a pathway for the metals to get into fish that use those invertebrates for food.”

He added that metals are likely getting into the animals from the sediment rather than the water. With time, he said, new layers naturally accumulating on the lakebed will decrease that risk, “but the metal contamination will never be completely eliminated from there.”

Asked about the mine’s continued dumping into Quesnel Lake and whether it could further impact aquatic life, he called it “a good question.”

“I’m as perplexed as anybody as to how they were given that approval after the mine disaster,” Pyle said. “Maybe they know something that we don't know, I’m not sure, but it does seem to me that pumping copper-contaminated water into an already contaminated system is not doing anything to help improve matters.”

Mount Polley responded to Pyle’s research on its website saying the findings confirm its own research and adding that while the increase in heavy metals in invertebrates may be “statistically significant” it is not “ecologically consequential.”

“The fish are healthy, and they don’t present a risk to people who eat those fish,” it concluded.

Pyle dismisses the company’s claim as “spin.”

“You wouldn’t really expect to see anything different from a corporation who’s responsible for one of the worst mine disasters in Canadian history,” he said.

“Even four years after this breach, we’re still detecting metals accumulating in these animals where the mining company had said that the metals are not likely bioavailable to them. They are bioavailable, even four years after the breach. That represents a pathway for those metals to get into the fish.”

Pyle’s work is part of a broader research project, led by University of Northern British Columbia geography professor Ellen Petticrew, that examines how fine tailings particles — Petticrew compares them to half the thickness of a human hair — continue to affect the lake.

“These small particles take a long, long time to settle,” Petticrew said.

While coarse tailings material from the 2014 disaster sits 15 metres deep in some areas of the lake bottom, potentially contributing dissolved metals into the water, it’s the movement of the fine particles that present the greater risk, she said. Research shows that semi-annual turnover of the lake water during spring and fall, when temperature changes cause water to recirculate, redistributes the fine sediment.

Petticrew points to UBC researcher Brody Granger’s work, which showed “tens of thousands of tonnes of especially small particles remained in suspension months later and are still detectable today.”

It found that particles were moving up — as well as down — the lake, sometimes against the current.

“His model indicates that in two years, we should be back to normal in terms of that fine material,” Petticrew added, noting that recirculation of the tailings material also causes it to flush out of the system through the Quesnel River.

But it brings the fine sediment into contact with lake life.

“Organisms are exposed to this contaminated material in the water column during periods of the year and their metal content is higher,” Petticrew said. “The implications on the food web are that it could potentially go higher. We’re not tracking that.”

Watt, who used lake water for everything at his home prior to the 2014 disaster, now brings clean drinking water in from Williams Lake.

While he says treatment options like reverse osmosis — something both more effective and more expensive than the current system — have been looked at in the past, he doesn’t believe that option is currently being examined.

A decision from the province about whether to grant Mount Polley an interim permit extension isn’t expected until later this year, he added. In the meantime, operations at the mine steadily increase.

“They’re counting on the extension to their permit,” Watt said. “They are ramping up. They’re already probably more than 50 per cent operating now.”  [Tyee]

  • Share:

Facts matter. Get The Tyee's in-depth journalism delivered to your inbox for free

Tyee Commenting Guidelines

Comments that violate guidelines risk being deleted, and violations may result in a temporary or permanent user ban. Maintain the spirit of good conversation to stay in the discussion.
*Please note The Tyee is not a forum for spreading misinformation about COVID-19, denying its existence or minimizing its risk to public health.


  • Be thoughtful about how your words may affect the communities you are addressing. Language matters
  • Challenge arguments, not commenters
  • Flag trolls and guideline violations
  • Treat all with respect and curiosity, learn from differences of opinion
  • Verify facts, debunk rumours, point out logical fallacies
  • Add context and background
  • Note typos and reporting blind spots
  • Stay on topic

Do not:

  • Use sexist, classist, racist, homophobic or transphobic language
  • Ridicule, misgender, bully, threaten, name call, troll or wish harm on others
  • Personally attack authors or contributors
  • Spread misinformation or perpetuate conspiracies
  • Libel, defame or publish falsehoods
  • Attempt to guess other commenters’ real-life identities
  • Post links without providing context


The Barometer

Do You Think Trudeau Will Survive the Next Election?

Take this week's poll