A proposed mining road in Northwest Alaska that would connect the Ambler mining district to the Fairbanks region has been blocked by the Biden administration which said it found “significant deficiencies” in a Trump-era environmental analysis of the road that would cut through wilderness and Indigenous territory in northwest Alaska.

The construction of Ambler Road is one of the most high-profile environmental issues in Alaska, as it would bring 211 miles of new road through one of the largest roadless areas in the country, the Washington Post reported.

The road includes about 50 miles of Bureau of Land Management and National Park Service land. In a statement, the Interior Department said in a statement that the road proposal would cross the traditional homelands of Alaska Native communities including the Koyukon, Tanana Athabascans and Iñupiat peoples.

In a federal court filing, the administration asked the U.S. District Court for Alaska to send the permit approval back to the department so it can conduct a new environmental analysis. Interior said that it would suspend the right of way for the road while it carried out the new assessment “to ensure that no ground-disturbing activity takes place that could potentially impact the resources in question.”

Alaska Native groups endorsed the decision.

“The 200+ Ambler road represents a fundamental threat to our people, our subsistence way of life and our cultural resources,” Brian Ridley, president of the Tanana Chiefs Conference, a nonprofit representing 42 tribes in interior Alaska, said in a statement. “We appreciate that the federal government recognized the flaws in the previous administration’s decisions to permit the road.”

The road, approved in July 2020, would run from the Dalton Highway north of Fairbanks west to the Ambler Mining District, where there are valuable deposits of zinc, copper, gold, cobalt and other metals. It has been a high priority for Alaska Gov. Mike Dunleavy (R) and the state’s congressional delegation.

Alaska’s congressional leaders, including its Republican senators, Lisa Murkowski and Dan Sullivan, condemned the Biden administration’s decision on the road and said it will harm Alaska.

“America’s lack of mineral security should be one of the Biden administration’s highest priorities, but its incoherent policies are making the problem worse,” Murkowski said in a statement. “It’s stunning: on the very same day the President attempted to tout ‘progress’ on mineral development, his administration backtracked and set back this crucial project, which will enable Alaska to responsibly produce a range of needed minerals.”

The mine developers, Ambler Metals LLC, — a joint venture between the Australian mining firm South32 Ltd. and Vancouver-based Trilogy Metals — and the Alaska Industrial Development and Export Authority, planned to spend nearly $60 million this year in preparation for the road and associated mines in the area.

Ambler Metals and the state development bank did not immediately respond to a request for comment.

Environmentalists and tribes have been concerned that the road and the associated mining projects that it would access would cause significant harm to rivers, streams and wildlife in the area. They have said the road would cross 11 river systems and require dozens of bridges and thousands of culverts.