New study details mining’s impacts on salmon habitat, even hundreds of miles downstream

Two men stand by a stream in a remote river valley
Jon Moore (left), professor at Simon Fraser University, and Mark Connor (right), Fisheries Coordinator for the Taku River Tlingit First Nation, stand on the banks of the Tulsequah River, which flows past the Tulsequah Chief and New Polaris Mines. (Photo courtesy of Chris Sergeant)

A new study shows that mines can have impacts on watersheds hundreds of miles downstream and years into the future. The paper’s authors say their analysis points to a need for more comprehensive risk consideration for mines to protect salmon watersheds throughout the Northwest.

There are thousands of coal and metal mines — both active and inactive — scattered throughout northwestern North America. A study published earlier this month in the journal Science Advances found a consistent pattern of harm to salmon habitat and watersheds from some of those mines.

“It is basically a smoking gun,” said Guy Archibald, the executive director of the Southeast Alaska Indigenous Transboundary Commission, a coalition of 15 tribal governments advocating for protections for watersheds shared by Alaska and British Columbia in Canada as well as tribal representation in the decision-making process for B.C. mines. He says the study is groundbreaking.

“We have observed for decades that mines in watersheds occur, and then salmon populations are harmed,” Archibald said. “But there’s never been a direct connection made between the mining activities and the harm to the salmon. This paper goes a long way to showing that.”

“I think that’s one of the things that’s really unique about this paper,” said study co-author Jonathan Moore, a salmon ecosystems scientist and professor at Simon Fraser University in Vancouver, British Columbia. “It brings together the state-of-the-art science about how these really complicated and changing river systems work with state-of-the-art mining understanding and how it’s regulated.”

Moore says the paper isn’t arguing against mining.

“What it is,” he said, “is arguing for the incorporation of best available science to guide mining, so it can be more sustainable.”

The study’s lead author, Chris Sergeant, is a research scientist with the University of Montana’s Flathead Lake Biological Station. He says the interplay of mining effects on salmon watersheds is compelling in part because it’s so complex.

“You need engineers, biologists, hydrologists, governance and policy people,” Sergeant said. “They all play a role in the mining world and how mines could potentially impact salmon — and in such an important place, like northwest North America, including Southeast Alaska, it’s one of the last best places for fish in the world.”

Sergeant says there’s no one-stop-shop for mining data, so they had to pull from a variety of sources — U.S. Geological Survey databases, data from mining industry resources, government agencies and academic literature. Study authors found numerous examples of mines having negative impacts on watersheds, even long after they were closed.

“We point out a river in the Coeur d’Alene watershed in Idaho, where even seventy years after mining had ended, the pollution that maintained because of that work continues to depress the populations of fish and aquatic insects in that stretch of river,” Sergeant said.

It can be a similar story hundreds of miles away from mines and across international borders.

“In the Elk Valley watershed in southern B.C. that flows in the Kootenay River, through Montana and Idaho back into B.C., there’s selenium pollution from coal mines that’s 250 kilometers downstream,” Sergeant said. “And that wasn’t really envisioned before those mines were built.”

The U.S. government is taking note. Last month, the Biden administration called on the Canadian government to participate in a joint investigation of that selenium pollution in the transboundary Elk Valley watershed. In 2020, Congress committed millions of dollars to transboundary watershed monitoring projects.

Whether or not mines and watersheds straddle borders, Sergeant also notes that mines are being proposed and built in more extreme environments — on mountains, across glaciers — as easy-to-reach areas are already tapped.

“You’ve got these feats of engineering to build mines in places where there are no roads or many humans at all,” Sergeant says, “And then on top of that, you’ve got climate change coming down the pike, where we’re getting more intense rain events, more landslides, more flooding, more drought.”

That puts additional, hard-to-predict pressures on the mine infrastructure. And extreme climate events are happening more and more frequently, says another co-author Nikki Skuce. She’s the director of the Northern Confluence Initiative and serves as co-chair of B.C. Mining Law Reform Network, a consortium of academics and community organizers pushing for changes to mining law in the province.

“We were hit with a heat dome, atmospheric rivers, catastrophic flooding, all within a six-month timeframe last year,” Skuce said. “There really needs to be a step up in the environmental assessment process for projects as well as for existing infrastructure like tailings dams to look at these climate risks.”

Tailings dams are earthen structures used to contain solid or liquid mining waste.

Sergeant says a prime example of unanticipated climate impact is the Red Dog Mine in Western Alaska, which was built in 1989.

“Because of unforeseen permafrost thaw, their water treatment facilities and their open pits are getting overwhelmed with more water than was ever envisioned,” Sergeant explains, “And that’s within a few decades of the project starting. Those are the kind of concerns — if we’re building these bigger and bigger mine projects, [taking into account the changing climate,] can we even do the engineering correctly?”

He points out that mines are critical for the transition to a low-carbon future. Copper and other minerals are essential parts of batteries for electric cars and other low-carbon alternatives.

“But this decision to build a large mine is going to impact the land for decades to centuries. And that needs to be thought about really carefully,” he said.

Moore says that the two-year process of putting together the study also exposed what he calls some “really massive black holes” in our understanding of the extent and impact of mining.

“Mining companies and other industries, at least in Canada, don’t necessarily need to share their data. It’s proprietary,” Moore said. “So the information that underpins their environmental assessments, underpins their monitoring, not all of it sees the light of day. I think that’s a real key challenge in terms of trying to assess the true risks of these projects.”

For study authors, the data point to a need for better transparency, more consideration of the cumulative effects of mines, and of the complex environmental stressors that could impact mines and watersheds due to the changing climate.

“I think we hope that this paper can be a resource that helps people make decisions in these landscapes,” Moore says, “To help people understand what might be at stake and what can be done about it, where policies might need to be improved, where science can be done better, where we need to think about who’s part of these conversations.”

From her side of the border, Skuce says she and B.C. Mining Law Reform are pushing to improve Canadian tailings dam safety standards and water management, in part by closing loopholes in the environmental assessment process that allows mining permits to be amended.

On the U.S. side, for Archibald and the tribal coalition, the study is clear evidence that the B.C. government should take into account a much wider swath of possible impacts when permitting mines.

“If they don’t talk to the downstream communities, if they don’t learn how these communities utilize the resource (salmon) and depend on the resource, then basically they’re making a decision without any information,” Archibald said. “That’s no way to manage a mine and a habitat.”

Mining Association of B.C., a mining industry group, did not respond to a request for comment.

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