First Nation warns of 'ecocide' as spring melt poses risk to tailings pond at Yukon mine site

The Little Salmon Carmacks First Nation is warning spring melt could cause the tailings dam at the abandoned Mount Nansen mine in central Yukon to overflow or breach, and send a toxic slurry into the environment.

The company managing the site, however, says a dam breach is unlikely — though it could be at risk of overflowing.

Little Salmon Carmacks Chief Nicole Tom calls it an emergency, and compared it to the 2014 Mount Polley mine disaster in B.C. that saw roughly 25 million cubic metres of water and tailings effluent flow into surrounding waterways. It was the largest tailings spill in Canadian history.

"The concern is ecocide," Tom said. "The concern is massive destruction of a territory, which holds our harvesting rights.

"This area, in which we consider sacred, it's medicine for us.

"At this point, there's very few caribou, there's no fish in the creek. It's like our earth has these big huge scars and sores all over the place. We've been living with this legacy of BYG for so long."

Tom is referring to BYG Resources, the company that used to operate the mine and was found guilty of "raping and pillaging" the land by Yukon Supreme Court in 2007.

Producing gold and silver in the 1990s, the Toronto-based company quickly went bankrupt and abandoned the mine. The site was then foisted onto the federal government, which now funds work to keep it stable. Eventually, Ottawa will also bankroll yet-to-be-approved closure and clean up efforts.

But it's getting to this last stage that the Little Salmon Carmacks First Nation states can't happen soon enough.

Enter the dam, which acts as a bulwark against mining refuse, and what could soon become of it.

Recently, the Mount Nansen Remediation Limited Partnership — hired by the federal government to manage the site — obtained an emergency amendment to its water licence so that crews can pump more water out of the tailings pond.

But Colin Prentice, the land manager with the Little Salmon Carmacks First Nation, said that hasn't been effective.

Prentice says the tailings dam can handle an additional 27,000 cubic metres of water. But he said roughly double that amount could enter the tailings pond in the coming months as snow melts, possibly enough to rupture the dam and create a problem with territory-wide implications.

"If that happens, an enormous plume of toxic tailings and mine-contaminated water is gonna run down Dome Creek, which heads toward White River and then the Yukon [River]," Prentice said.

"This is an impending crisis. We have an opportunity to prevent a disaster."

Dam breach 'not considered likely,' company says

However, the remediation company that's now managing the mine site said the tailings dam is not about to fail.

Jim Harrington, the director of the Mount Nansen Remediation, told CBC News the dam is not unstable and, worst-case, it's designed to overflow.

"The dam-breach scenario that you're talking about is not considered likely," he said, "but the potential for overflow of untreated water to the environment, which would not be good, is certainly a risk."

Harrington said water levels on site are indeed "higher than they should be."

"Even if we could treat at its maximum rate the [water treatment plant] was designed for, we're still not making much headway," he said. "We're likely to need to bring in additional treatment capacity to get more water off the site."

That looks like bigger systems for water treatment and diversion, as well as upgrades to the dam, Harrington said.

"All of those things are being considered right now."

"We have all the same concerns," he said, adding the company first broached problems about the dam last year, prompting the emergency water licence amendment.

Speaking to reporters during the Yukon Forum last week, Premier Ranj Pillai said his government is collecting more information about the problem.

"Yes, we're extremely focused on making sure that the concerns that the chief had today have been listened to, and we're acting on those things," he said.

Yukon's MP Brendan Hanley also told CBC News he acknowledges the urgency of the situation.

"Definitely on our radar," he said. "I don't have an answer for Chief Tom yet, but we did discuss it, just the other day."

Crown-Indigenous Relations and Northern Affairs, the federal department ultimately responsible for the site, didn't immediately return requests for comment.

'Screaming at the top of our lungs' for help, chief says

Chief Tom said the problems that have created the current emergency have for years been hiding in plain sight, underscoring that work to stabilize the site is deficient. Tom ultimately chocks that up to failure by successive governments.

"At this point," Tom said, "we're just screaming at the top of our lungs to get some help here and so people listen to what we're saying, because [a breach of the dam] will cause so much further destruction.

"We are sticking up for the animals and the fish and the lands that have no voice."

The First Nation is calling on the federal government for immediate, emergency funding to treat and draw down water.

The First Nation also recently lodged a complaint with the Yukon Water Board that argues, among other things, care and maintenance is hobbling reclamation plans and that Mount Nansen Remediation is routinely breaching its water use licence. The First Nation also states the territorial and federal governments are "in breach of their treaty obligations." The First Nation's demands include a more powerful water treatment plant, capable of filtering dozens of heavy metals, and expanded monitoring efforts.

The federal government is dismissing those claims, arguing the company is meeting the parameters of its current water licence and that the water board lacks jurisdiction to resolve the First Nation's concerns.

The First Nation has since clapped back and doubled down on its original demands. In a new response filed to the water board last week, it states the Yukon and federal governments "each categorically fail" to acknowledge traditional knowledge and that the land is facing collateral damage, which is key to recognize in order to implement treaty rights.