Federal environmental review begins for the Arctic copper mine near Kobuk

Trilogy Metals Inc. told the Securities and Exchange Commission on Sept. 21 that the Army Corps of Engineers has published notice that it will prepare an environmental impact statement for the proposed Arctic copper mine in the Ambler mining district. That opens the scoping phase, when the public helps decide what the study will examine, including alternatives and the option of not building the mine at all.

The deadline for public comments isn't known yet. As of Sept. 21 the notice had not appeared in the Federal Register, so the closing date and how to comment could not be confirmed. Trilogy's announcement doesn't say either.

The project is held by Ambler Metals LLC, a joint venture owned equally by Trilogy and a subsidiary of South32 Limited. The federal Permitting Dashboard describes an open pit mine at the Arctic Deposit processing about 11,000 short tons of ore a day, producing copper, zinc, lead, gold and silver, near Kobuk in the Northwest Arctic Borough. It lists an estimated completion date of Nov. 26, 2028, for all 15 federal reviews and permits the project needs, none of them finished yet. The Corps is the lead agency.

The Corps received Ambler Metals' application for a Clean Water Act permit to dredge and fill wetlands and streams on April 20, 2026. The review runs under FAST-41, a federal program that coordinates permitting on a published timetable. Trilogy says that schedule runs 29 months, targeting a draft environmental impact statement in October 2027 and a final decision in September 2028.

The project depends on the Ambler Access Project, a proposed 211-mile industrial road from the Dalton Highway that has not been built. Its federal authorizations were restored through a presidential decision on Oct. 6, 2025. Separately, the U.S. Department of War closed a $35.6 million investment in Trilogy Metals on Sept. 11, giving the government about a 10 percent stake.

Tanana Chiefs Conference, which condemned the road decision in an October 2025 statement, and affiliated tribes have opposed the road and mine, citing harm to fish, wildlife and subsistence communities. The Kobuk Tribal Council and Allakaket's First Chief, PJ Simon, a former Tanana Chiefs Conference chief, have backed the project, citing the need for jobs as Red Dog Mine winds down and as salmon and caribou populations decline.