Ambler Road Project in Alaska: Cost, Approvals, and Lawsuits

The Ambler Road Project is a proposed 211-mile private industrial road in northern Alaska that would run west from the Dalton Highway to the Ambler Mining District, a remote copper-zinc belt south of the Brooks Range. After federal rejection in June 2024 and presidential approval in October 2025, the project now holds reinstated federal permits but faces active litigation that could still halt construction.

What the Road Would Be and Where It Would Go

The route runs 211 miles westward from milepost 161 on the Dalton Highway to the south bank of the Ambler River, staying on the south side of the Brooks Range. The corridor crosses a mix of ownership: roughly 61 percent state land, 24 percent federal land, and 15 percent Alaska Native corporation land.¹ About 26 miles pass through the Western (Kobuk River) unit of Gates of the Arctic National Preserve, and the road would cross nearly 3,000 rivers and streams, including the Kobuk Wild and Scenic River.²

This is not a public highway. The road is designed as a controlled-access industrial facility: no public traffic, and no hunting from the road.³ Construction would proceed in three phases over four to six years, and the road is designed to operate for up to 50 years.¹

Why the Road Is Being Built

The Ambler Mining District holds more than 1,700 active mining claims and contains copper, zinc, cobalt, gallium, germanium, silver, gold, and lead.⁴ Without surface transportation, those deposits are effectively stranded, which is the Alaska Industrial Development and Export Authority’s (AIDEA) core argument for building the road.¹

Two deposits anchor the economic case, both held by Ambler Metals LLC, a 50/50 joint venture of Trilogy Metals Inc. and South32 Limited:

Arctic, a polymetallic deposit with roughly 43 million metric tons of reserves averaging 2.32 percent copper and 3.24 percent zinc. The proposed mine would produce about 10,000 tons of ore per day over 12 to 13 years.⁵
Bornite, a copper-cobalt deposit about 16 miles southwest of Arctic, with an estimated 208.9 million tonnes of inferred resources grading 1.42 percent copper, plus cobalt and germanium potential.⁶

The Trump administration has framed these as critical minerals essential to national defense and economic security.⁴

How the Project Got Approved, Rejected, and Approved Again

The permitting history is unusual, and understanding it is the only way to make sense of where the project stands now.

The Bureau of Land Management (BLM) published a final Environmental Impact Statement in March 2020. In July 2020, during President Trump’s first term, the BLM and U.S. Army Corps of Engineers issued a joint Record of Decision approving the project and granting AIDEA a 50-year right-of-way.⁷ Environmental groups and Alaska Native tribes immediately sued. In February 2022, the Department of the Interior requested a voluntary remand to redo portions of its analysis; the court granted the remand in May 2022 but kept jurisdiction over the cases.⁸

On June 27, 2024, the BLM issued a new Record of Decision selecting the “No Action Alternative,” effectively killing the project. The agency concluded that all action alternatives would cause significant, irreparable harm to subsistence resources in at least 30 Alaska Native communities and that it could not satisfy Section 810 of the Alaska National Interest Lands Conservation Act (ANILCA), which precludes granting a right-of-way under those circumstances.⁹ On January 15, 2025, days before leaving office, the Biden administration’s Pentagon ordered the Army Corps to revoke the project’s Clean Water Act Section 404 permits, though the Corps later indicated those permits were suspended rather than fully revoked. The administration also terminated the project’s National Historic Preservation Act Programmatic Agreement.¹⁰

In June 2025, AIDEA filed a 92-page appeal invoking Section 1106(a) of ANILCA, a provision that lets an applicant appeal a rejected transportation project directly to the president when the route does not cross designated wilderness.¹¹ No president had used the provision in the 45 years since ANILCA’s enactment in 1980.¹²

On October 6, 2025, President Trump approved the appeal, directing the BLM, National Park Service, and Army Corps to reissue all necessary permits within 30 days.¹³ The decision found the road “in the public interest given our need for access to domestic critical minerals,” compatible with the purposes of Gates of the Arctic National Preserve, and the only economically feasible and prudent route.⁴ It also stated that ANILCA requires no further review under NEPA or the National Historic Preservation Act after a presidential approval under Section 1106(a).¹⁴

By October 21, 2025, the BLM had reissued its 50-year right-of-way grant and the National Park Service had reissued its right-of-way permit. The Army Corps reinstated its Clean Water Act Section 404 and Rivers and Harbors Act Section 10 permits, each with fresh 15-year terms.¹⁴

What It Will Cost and Who Is Paying

Cost estimates have moved considerably over time. A BLM fact sheet from the original EIS cited $350 million for full construction, with annual operations and maintenance of $8 to $10 million.¹ By 2024, the BLM’s own analysis estimated $672.4 million, and conservation groups have cited figures above $1 billion once financing and associated infrastructure are included.¹⁵

AIDEA has envisioned a public-private partnership to finance, build, and operate the road. The AIDEA board set aside $35 million in 2020 and, on October 22, 2025, unanimously committed another $50 million from its revolving fund.¹⁶ AIDEA’s 2024 effort to have the Alaska Legislature increase its debt capacity by $300 million for mining-related projects was rejected by the House Finance Committee.¹⁵

Separately, the federal government announced a $35.6 million strategic equity investment in Trilogy Metals on October 6, 2025, acquiring a 10 percent stake plus warrants for an additional 7.5 percent. The investment was made under Title III of the Defense Production Act, with the closing deadline extended to July 31, 2026.¹⁷

Alaska Native Positions

Response from Alaska Native communities has split largely along geography. Tribes whose traditional lands lie along the route have generally opposed the road; the regional corporations whose shareholders live near the mining district have sought to shape its terms.

The Tanana Chiefs Conference (TCC), representing 42 Interior Alaska tribes, has formally opposed the road since 2018, when its full board passed a resolution against the project and “any future roads to Ambler or surrounding territory.” TCC’s concerns focus on caribou, sheefish, and salmon, acid mine drainage from sulfide mining potentially contaminating the Koyukuk, Alatna, John, and Henshaw watersheds, and harm to Indigenous ways of life.¹⁸ After the October 2025 approval, TCC chairman Brian Ridley called the decision “a direct affront to the voices of Alaska Native people” that “places corporate and extractive agendas over our rights, our lands, and our future.”¹⁹ A consultant for several tribes reported that 88 tribal governments have expressed opposition.²⁰

NANA Regional Corporation, the Iñupiat corporation for Northwest Alaska, holds surface rights in the mining district area. NANA initially allowed AIDEA to conduct preliminary work on its land but formally withdrew from the project in May 2024, citing AIDEA’s failure to satisfy requirements on controlled access, caribou migration, job creation, and community benefits. CEO John Lincoln said subsistence remained the “best use of our lands” and that development decisions must be made “by and with our people at the table.”²¹

That posture softened after the presidential approval. In early December 2025, NANA and Doyon Limited (the Interior Alaska Native regional corporation, which also owns land along the route) signed a nonbinding memorandum of understanding with AIDEA, Ambler Metals, K’oyitl’ots’ina Ltd., the U.S. Department of the Interior, and the Alaska Department of Fish and Game. The MOU is not a final commitment. NANA’s January 2026 shareholder letter set conditions for any further engagement: guaranteed jobs for Indigenous shareholders, strong subsistence protections, and limiting road access to private and industrial traffic only. The agreement also starts the process of forming a legal entity to oversee permits, easements, and rights associated with the road.²²

Environmental Stakes

The BLM’s 2024 supplemental analysis found the project’s effects on subsistence were significant and irreparable across the action alternatives, and that finding was the core basis for the Biden-era rejection.⁹

The Western Arctic Caribou Herd is the highest-profile ecological concern. The herd has declined from roughly 490,000 animals in 2003 to 152,000 in 2023. The National Parks Conservation Association asserts the road would “sever the migration route.”² A report commissioned by AIDEA offers a different reading: the route does not lie in the herd’s primary calving or summer ranges, which are 60 to 170 miles to the north and west, and between 2010 and 2022 an average of only 3 percent of collared caribou crossed the route in fall and 4.8 percent in winter. The report attributes the herd’s decline primarily to predation and severe weather rather than infrastructure.²³

Other concerns include the nearly 3,000 waterway crossings, disruption to fish habitat, permafrost degradation, and the opening of a vast roadless area to industrial activity. Opponents argue that associated open-pit copper mining could generate acid drainage reaching downstream watersheds flowing into the Yukon River and ultimately the Bering Sea.¹⁸

The Lawsuits That Could Still Stop It

Two parallel cases have been pending in the U.S. District Court for the District of Alaska since 2020:

Northern Alaska Environmental Center v. Haaland (3:20-cv-00187), filed by ten conservation groups including the Sierra Club, the Wilderness Society, the National Parks Conservation Association, and Alaska Wilderness League, represented by Trustees for Alaska. The case challenges the federal approvals on NEPA, ANILCA, Clean Water Act, and Federal Land Policy and Management Act (FLPMA) grounds.²⁴
Alatna Village Council v. Padgett (3:20-cv-00253), originally filed by six tribal councils and the Tanana Chiefs Conference, alleging violations of ANILCA, NEPA, the National Historic Preservation Act, the Clean Water Act, and FLPMA. Two councils, Allakaket and Huslia, voted to withdraw from the lawsuit in February 2023.²⁵

Because the court retained jurisdiction when it granted the 2022 remand, plaintiffs have a live forum. On January 23, 2026, the conservation plaintiffs filed an amended and supplemental complaint arguing the BLM, National Park Service, and Army Corps exceeded their authority by reissuing permits, and that the president himself acted beyond ANILCA. The complaint alleges violations of ANILCA, NEPA, the Clean Water Act, and FLPMA.²⁴ As of mid-2026, no injunction has been reported. Bridget Psarianos of Trustees for Alaska has said “there is still a lot of fight left in this issue.”¹¹

Where Things Stand in 2026

The project has federal permits in hand but no firm construction date. Field crews returned to the corridor in April 2026 to begin geotechnical investigations, hydrology and hydraulics studies, fish habitat surveys, and permafrost research. The work, conducted by Qayaq Construction LLC and HDR Engineering Inc. alongside the Alaska Department of Fish and Game, is intended to advance designs toward construction-ready plans and fill data gaps.²⁶

On the mining side, Ambler Metals filed a Clean Water Act Section 404 permit application for the Arctic mine itself with the Army Corps in April 2026, and the project was accepted as a “Covered Project” under the federal FAST-41 expedited permitting program in May 2026. The joint venture approved a $35 million budget for 2026 field work, including engineering for Arctic and preparation for possible accelerated development of Bornite in 2027.¹⁷

Whether the unprecedented use of ANILCA Section 1106(a) survives judicial review will likely determine whether the Ambler Road is built.

1
Bureau of Land Management. Ambler Road EIS Fact Sheet
2
National Parks Conservation Association. 20 Million Acres of National Park Lands Threatened
3
Alaska Department of Natural Resources. Ambler Road
4
The White House. Fact Sheet: President Donald J. Trump Approves Ambler Road Project
5
Mining News North. Road Reevaluation Stalls Ambler Metals
6
Trilogy Metals. Trilogy Metals Announces Commencement of Permitting for Arctic Project
7
Federal Register. Notice of Availability of the Record of Decision for the Ambler Mining District Industrial Access Road
8
BLM ePlanning. Ambler Road Project
9
U.S. Department of the Interior. Biden-Harris Administration Takes Steps to Protect Tribal Subsistence, Vital Ecosystems
10
Alaska Public Media. Ambler Road Project Remains in Limbo After Army Corps of Engineers Waited Months to Revoke Permits
11
Northern Journal. Trump Has Given New Life to the Ambler Road, But It’s Still Not a Sure Thing
12
Mining News North. Ambler Road Executive Order Shines
13
The White House. Decision of the President and Statement of Reasons on 2025 Ambler Road Appeal
14
The White House. Presidential Decision on the 2025 Ambler Road Appeal
15
Anchorage Daily News. AIDEA Board Commits $50 Million Toward the Ambler Road Project
16
AIDEA. Resolution G25-09 – Ambler Access Project Funding
17
Trilogy Metals. Trilogy Metals Provides Update on U.S. Department of War Strategic Equity Investment
18
Tanana Chiefs Conference. Resolution 2018-06
19
Tanana Chiefs Conference. Tanana Chiefs Conference Condemns Decision to Advance Ambler Road
20
KOTZ. Federal Government Transfers Land in Ambler Road District to NANA Regional Corporation
21
NANA Regional Corporation. NANA Regional Corporation Withdraws From the Ambler Access Project
22
Alaska Beacon. In New Agreement With State, Indigenous Landowners Soften Resistance to Ambler Road
23
AIDEA. Cronin Final Report – Ambler Road Caribou Information for AIDEA
24
Sierra Club. Legal Filing Challenges Trump and Interior Approvals of Ambler Mining Road
25
Alaska’s News Source. 2 Tribal Councils Withdraw From Ambler Road Lawsuit
26
AIDEA. Field Season Begins Along Ambler Road Corridor