Corps Released New Donlin Gold Mine Spill Report
The U.S. Army Corps of Engineers draft report analyzes a potential 27% tailings dam spill scenario.
Updated on Sept. 25, 2026 in Environmental
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The U.S. Army Corps of Engineers released a draft environmental report for the proposed 27-year Donlin Gold mine operation. The new study models a 27% tailings dam spill, significantly increasing the risk profile from a 2018 assessment that modeled a 0.5% failure.
Why it matters
A federal judge ordered this supplemental report following litigation by the Orutsararmiut Native Council regarding environmental risks. The federal government will use these findings to determine whether permitting for the Alaska-based mining project requires adjustments.
The draft report models the failure of the tailings storage facility, located 10 miles from Crooked Creek. This study evaluates impacts over the project's 27-year operation timeline.
The players
U.S. Army Corps of Engineers
This federal agency manages the permitting process for large-scale infrastructure and mining projects that impact waterways.
Donlin Gold
This mining company is the primary entity proposing the development of the gold mine operation in Alaska.
Orutsararmiut Native Council
This tribal government organization initiated the litigation that forced the supplemental review of the mine's environmental risks.
Earthjustice
This non-profit public interest law organization is involved in legal advocacy related to environmental protection and mining oversight.
The details
The U.S. Army Corps of Engineers released the draft following court-ordered review of spill risks. Donlin Gold maintains that the tailings storage facility design has remained unchanged since the initial environmental assessment.
Timeline
The original environmental assessment was conducted in 2018.
The draft supplemental environmental report was released on September 25, 2026.
Four public hearings will be held between October 14 and October 19, 2026.
The public comment period is scheduled to close on October 23, 2026.
Deeper Dive
This draft report serves as a critical update to the environmental record within the National Environmental Policy Act (NEPA) federal permitting process. It reflects an evolving regulatory landscape where federal agencies must incorporate more rigorous spill risk analysis for long-term mining projects.
Residents in communities along the Kuskokwim River, including those near Aniak and Bethel, can provide formal feedback during the upcoming public hearings. This process directly influences the federal oversight that determines whether the mine proceeds and what safety standards are required.
The takeaway
The updated spill analysis represents a significant shift in the environmental assessment of large-scale infrastructure projects. Residents are encouraged to review the draft findings to understand how federal modeling of long-term risk impacts the local environment.
What happens next
The public comment period closes on October 23, 2026, after which federal agencies will finalize the report and proceed with permitting determinations.
Further reading
Learn more about local environmental monitoring at the Environmental section.
More information
Access public hearing details and portal to review the draft report and submit comments.
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