Army Corps Released Draft Report on Donlin Gold Mine
The supplemental environmental report updates spill risk modeling for the proposed 27-year mining project in Alaska.
Updated on Sept. 25, 2026 in Environmental
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The U.S. Army Corps of Engineers has released a draft supplemental environmental report that models a potential 27% tailings dam spill at the proposed Donlin Gold mine site. This report follows litigation regarding spill risks and precedes upcoming public hearings.
Why it matters
The updated modeling is the result of a federal court order following a lawsuit from the Orutsararmiut Native Council. The findings will inform whether federal agencies modify the permitting process for the project, which is planned to operate for 27 years.
The new draft report evaluates the environmental impacts of a 27% tailings dam failure, a significant increase from the 0.5% spill percentage used in the 2018 environmental assessment. Donlin Gold maintains that the design of the tailings storage facility has not been altered.
The players
U.S. Army Corps of Engineers
The federal agency responsible for evaluating infrastructure projects and managing the environmental permitting process.
Donlin Gold
The company behind the proposed long-term gold mining operation that would span 27 years.
Orutsararmiut Native Council
A tribal organization that initiated the litigation regarding spill risks at the proposed mine site.
The details
The U.S. Army Corps of Engineers uses numerical modeling to predict the potential environmental impacts of infrastructure projects to guide the federal permitting process. This draft report specifically examines how a breach of the tailings dam—a structure used to store byproduct material from mining—would affect surrounding land and waterways, including the Kuskokwim River and the area near Crooked Creek. The study was mandated after a federal judge ordered a review of spill risks following legal challenges.
Timeline
2018: Original environmental assessment modeled a 0.5% spill.
September 25, 2026: Draft supplemental environmental report was released.
October 14-19, 2026: Series of four public hearings are being conducted.
October 23, 2026: Public comment period closes.
The Tech Race
This draft report represents a critical milestone in the federal oversight of large-scale mining operations in Alaska. It updates a 2018 environmental assessment and serves as the primary mechanism for resolving legal disputes over long-term environmental safety standards.
Residents and stakeholders have until October 23, 2026, to submit formal comments on the draft findings. Public hearings will be held between October 14 and October 19 to provide Alaskans an opportunity to participate in the federal review process.
The takeaway
The updated modeling significantly raises the spill risk profile analyzed for the project compared to 2018 projections. Interested parties should track the conclusion of the public comment period on October 23, 2026, which will precede the final federal permitting determination.
Further reading
Explore ongoing Environmental studies and federal permitting updates for projects across Alaska.
More information
For official documentation, schedule information for hearings, or to submit feedback, visit the public hearing details and portal.
Source note: This article includes information reported by KYUK.
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