The U.S. Forest Service has laid out a plan to allow Stillwater Mining Company to continue operating the East Boulder platinum and palladium mine into the 2040s.
The Custer Gallatin National Forest this week released an environmental impact statement establishing its preference for an expansion of waste rock and tailings storage that would extend the mine’s life and grow its permitted footprint by 474 acres, most of which are on national forest land.
In response to public input, the Forest Service made a few tweaks to the company’s original proposal. The changes incorporated in the draft EIS increase the stability of the proposed tailings dam, which will help protect the East Boulder and Yellowstone rivers from nitrate-laden tailings in the event of an earthquake or extreme rainfall.
If the Forest Service were to deny SMC’s proposal altogether, the East Boulder Mine would run out of places to store waste rock, material it pulls from the earth to construct new mining tunnels, in about a year. The mine also needs to expand its tailings storage facility to continue production, though the timeline for that operational piece of the puzzle isn’t as tight.
In a release accompanying the final EIS, the Forest Service said the waste rock storage area could accommodate a 1-in-200-year, 24-hour precipitation event, an improvement from the design that had been originally proposed by Stillwater Mining Company, which would withstand a 1-in-100-year event. Other changes it made in response to public comment include revisions to the reclamation component of the plan geared toward reducing erosion, improving revegetation and giving the site a more natural appearance when the mine is shuttered.
“We are pleased to release the Draft Decision and Final EIS and continue moving the process forward,” Custer Gallatin Forest Supervisor Mary Erickson said in the agency’s release. “The comments we received are reflected in the documents, and we look forward to working through the objection process with those who have standing over the next few months.”
The Forest Service’s issuance of the draft EIS on Nov. 28 started a 45-day timer for parties with concerns to raise their objections before the Forest Service and Department of Environmental Quality issue a final EIS and record of decision.
Earlier this year, Earthworks and Trout Unlimited released an engineering firm-generated video simulating the distance tailings would travel in the event of an impoundment failure wrought by “probable maximum flood conditions.” It shows tailings being carried from the mine’s location at the headwaters of the East Boulder River down through the Boulder River itself and into the Yellowstone River near Big Timber. Along the way, 50 miles of habitat for aquatic species, including the region’s famed trout, would be contaminated with tailings. In a press release accompanying the release of the video, Bonnie Gestring with Earthworks argued that public health and safety should come first in mine waste management.
“Despite industry promises, the reality is that tailings dams fail, and severe tailings dam failures are happening more frequently,” Gestring said. “It’s essential that the agencies consider the most protective options during the mine permitting process.”
The video simulation was based on the mine’s original proposal for mine waste storage that Stillwater Mining Company forwarded to DEQ and the Forest Service in 2020.
The East Boulder Mine has operated since 2001 and employs about 550 people. Stillwater Mining Company, a subsidiary of a South Africa-based mining company named Sibanye-Stillwater, operates the East Boulder Mine and the Stillwater Mine located near Nye.
Sweet Grass County resident Jerry Iverson said public input the Forest Service received during the scoping process is reflected in the agency’s draft EIS.
“I really commend the Forest Service and the DEQ for this really sincere — and, I think, thorough — evaluation of this project,” Iverson told Montana Free Press.
Iverson has for decades engaged with operators and regulators of the East Boulder Mine as a member of the Cottonwood Resource Council, a chapter of the Northern Plains Resource Council that was formed in response to concerns surrounding mine development. In 2001, Iverson helped negotiate the terms of the Good Neighbor Agreement, a legally enforceable contract that puts limits around mine operations to protect the environmental and quality-of-life interests of those living near the Stillwater and East Boulder mines.
Iverson said the tailings storage has to be safe and well-constructed, particularly given its size and where it’s located — in the headwaters of a wild, sparsely populated mountain valley a few miles from the boundary of the Absaroka-Beartooth Wilderness.
Iverson said he supports the Forest Service’s decision to beef up the impoundment design to accommodate a more severe flooding scenario and appreciates changes that allow for more natural stormwater drainage and a “more aesthetically acceptable” landscape once the mine closes.
He noted that one thing groups such as Trout Unlimited and Earthworks had asked for didn’t make it into the EIS. That’s the requirement that the mine operator use a more advanced technology to extract water from the tailings and make them less capable of being carried downstream. That technology is more protective of water quality but also more expensive.
That type of treatment is not economically or technologically feasible right now, according to the Forest Service. An analysis prepared by the agency estimates the mine would require a $36 million capital outlay for additional buildings and infrastructure to switch to a filtered tailings system.
The vice president for the Sibanye-Stillwaters Americas operation told MTFP that using filtered tailings treatment would throw a wrench in its current mine waste management system, which is set up to put about half of the tailings back underground so they can be used in a cement-like mixture that supports the construction of new mining tunnels.
“It’s a bit of a technical conundrum,” Heather McDowell said. “We want to be able to put half of our tails back underground because that means [they] don’t have to be stored at the surface. We think from a sustainability standpoint that is the right thing to do.”
McDowell added that while it’s not feasible for Sibanye-Stillwater right now, the company has committed to continuing to study that technology.
Dan Vermillion, who owns a Livingston-based fishing outfitting business and agricultural property in Sweet Grass County, said his understanding is that the technology exists, it’s just expensive. It’s rolled into that “age-old” question about protective regulation versus overly restrictive regulation, he said. “What I consider to be adequate regulation someone else considers to be overkill.”
“I think we just have to hope that their predictions are accurate. But it’s hard to predict the future and our future depends on the quality of that water,” Vermillion said. “The implications of a failure are pretty huge for people living downstream.”
In other news, Stillwater Mining Company initiated a 100-person layoff on Tuesday, McDowell confirmed. The vast majority of employees that will be laid off work at the Stillwater Mine, McDowell said, adding that falling prices for palladium have driven the employment cuts.
