Donlin dam failure could put lives at risk and harm fish habitat, study says

New analysis of the Alaska mine, ordered by a federal judge, considers larger releases from potential breaks in the dam planned to hold mining waste

The Donlin Gold mine camp is seen from the air, June 23, 2025. The site holds 40 million ounces of gold, according to Novagold Resources, the majority owner of Donlin Gold. If developed, the mine would excavate gold from an open pit extending more than 2 miles in length, with a waste held by a 471-foot-high dam. (Yereth Rosen/Alaska Beacon)

By Yereth Rosen

Alaska Beacon

A major dam failure at the huge gold mine proposed for rural Western Alaska could unleash catastrophic flooding that would make one village uninhabitable, poison drinking water sources and cause lasting damage to fish habitat, according to a new analysis by federal regulators.

The hypothetical disaster is described in a draft supplemental environmental impact statement the U.S. Army Corps of Engineers prepared for the Donlin Gold mine.

The supplemental EIS, released by the Corps last week, was mandated by a court order issued last year. That order followed a 2024 ruling by U.S. District Court Judge Sharon Gleason that found that the Corps’ previous study of Donlin environmental impacts improperly understated the risks of major break in the dam that Donlin proposes to build to hold its mining waste, known as tailings. 

The Corps’ original environmental impact statement, completed in 2018, analyzed a potential release of up to 0.5% of the millions of tons of material held behind the planned 471-foot-high dam. Shortly after that study was released, the Corps and the U.S. Bureau of Land Management gave their approvals for mine construction.

Gleason’s ruling did not overturn the permits.

The new study, launched in January, evaluates potential results from dam breaches releasing 5.4%, 13.3% and 27% of the total tailings volume.

As hypothetical spill sizes increase, potential impacts become more severe, causing special risks to the village of Crooked Creek, about 10 miles from the mine, the draft said.

“Larger spills would generate much larger flood waves, inundate thousands of acres, flood portions of the Village of Crooked Creek, alter stream channels, and deposit large volumes of tailings throughout the drainage,” the document said.

At risk are the health and safety of people living nearby, the draft SEIS said.

“Risks include contaminant exposure, drinking-water concerns, psychosocial stress, displacement, and potential loss of life in heavily affected areas. The 27 percent scenario could render parts of the Village of Crooked Creek uninhabitable and create significant public-safety challenges,” the document said.

There are also risks to fish in the region: “Larger spills could cause population-level impacts lasting years to decades in Crooked Creek, with the 27 percent scenario potentially causing generational effects,” the draft said.

The maximum 27% spill scenario is based on a comprehensive 2022 study of dam failures at mines, the Corps said.

Comments on the draft will be accepted until Oct. 23, the Corps said.

Mine opponents said the new analysis vindicates their arguments that the mine poses unacceptable dangers in a region in which communities are dependent on salmon and healthy fish habitat.

“The findings in this document are a validation of our deepest fears and a clear signal that this project is far too dangerous for western Alaska. While we implored the federal government to consider a total failure scenario, which they did not do, they are confirming that a dam failure of just 27% could kill people, poison our drinking water for decades, and wipe out salmon for generations. We cannot, and will not, trade the safety of our children and our rivers for a gold mine that will last only 27 years,” Ashlynn Simeon, deputy director of the Mother Kuskokwim Tribal Coalition, said in a statement.

The coalition was founded by Yup’ik tribal members in the region who oppose the mine. 

One of the attorneys representing the tribal mine opponents said the Corps and BLM erred by using the 27% figure as the maximum release scenario.

“We disagree that pulling a figure based on an average from that dataset is the right way to go about this. We think it is important for the Corps and BLM to look at a full spill because a full spill is a foreseeable potential consequence of building this mine. Many tailings dams have failed across the world, and they have spilled up to 100% of their contents,” Hannah Payne Foster of Earthjustice, the environmental law firm representing the tribal plaintiffs, said by email.

While a spill of 27% of the dammed content would be “disastrous” for some communities, a larger spill would affect even more communities, she said. Without analysis of a bigger spill, residents of a wider area would lack some key information, such as the amount of time they would have to evacuate their villages. Additionally, she said, the mine tailings will pose threats long after mining ceases. They “do not go away when mining ends; they must be held in place in perpetuity.”

Donlin Gold said it will evaluate the draft environmental impact study and stay engaged in the public review process.

In a statement, Donlin Gold said it is committed to protective standards “well beyond the regulatory process.” That includes its design for the tailings storage facility is consistent with that approach, the company said.

“The facility will have multiple layers of protection and oversight from our own engineers designing and monitoring the facility, to independent engineering review, Alaska Native landowners, and the State of Alaska engineers and regulators,” Todd Dahlman, Donlin Gold’s general manager, said in the statement. “These layers provide multiple checks on the design, construction, and operation of the facility, as well as ongoing monitoring to help identify and address potential issues before they become a problem.”

Calista Corporation, the regional Native corporation that owns the mineral rights that Donlin would develop and has partnered with the mining company, said it is also evaluating the supplemental impact statement and will submit comments.

The Donlin Gold project would commercialize gold deposits estimated at 40 million ounces, according to Donlin Gold’s major owner, Canada-based Novagold Resources. It is “one of the largest known development-stage gold deposits today,” the company’s website says.

The scale of the proposed mine is massive.

It would encompass an open pit more than 2 miles long, the tailings facility and its 471-foot-high dam, a natural gas pipeline running more than 300 miles from Cook Inlet, a natural gas-fired power plant, road and port facilities, and airstrip and related items, according to the Corps’ description.

Alaska Native sentiments about the mine are divided. Calista and the Kuskokwim Corp., the Native corporation that owns the surface where the project is located, are partners with Donlin Gold and have described the project as offering much-needed economic opportunity in the state’s poorest region. Donlin revenues would also be shared with Alaska’s other Native corporations, making the project of statewide economic interest.

But many Yup’ik residents in the region oppose the project because of the risks they see to salmon in the Kuskokwim River area and other natural resources that support traditional lifestyles. They argue that the risks outweigh the potential economic benefits.

Development of the Donlin mine has been considered for decades. The gold at the site was discovered in the 1980s.

Last year, the Trump administration selected the Donlin mine for inclusion in a program called FAST-41, in which permitting is streamlined and coordinated.

One of the key investors in the Donlin project is John Paulson, a billionaire hedge fund owner who is close to Trump.

Paulson last year bought 40% of Donlin Gold after Barrick Gold Corporation, an international mining giant, dropped out of the project. In July, Paulson struck an agreement with Novagold to consolidate their ownership. Under the agreement, Novagold will get Paulson’s shares in Donlin and Paulson will have a major ownership stake in the reformulated Novagold.

• Yereth Rosen came to Alaska in 1987 to work for the Anchorage Times. She has been reporting on Alaska news ever since, covering stories ranging from oil spills to sled-dog races. She has reported for Reuters, for the Alaska Dispatch News, for Arctic Today and for other organizations. Alaska Beacon is part of States Newsroom, the nation’s largest state-focused nonprofit news organization.