RENO, Nev. (AP) — The latest bid by conservationists and tribal leaders to block construction of a huge lithium mine already in the works along the Nevada-Oregon line was denied by the 9th U.S. Circuit Court of Appeals on Monday.

A three-panel judge of the San Francisco-based appellate court rejected a half-dozen legal arguments the opponents had put forth in their appeal seeking to overturn federal land managers’ approval of one of the projects at the forefront of President Joe Biden’s plans to combat climate change.

The critics have been fighting it in federal court for two years. They claim the open-pit mine, as deep as the length of a football field, will violate multiple environmental laws and destroy lands tribal members consider sacred because they say dozens of their ancestors were massacred there in 1865.

Lithium Nevada Corp.’s mine at Thacker Pass, 200 miles (320 kilometers) northeast of Reno, has pitted environmentalists and Native Americans against Biden’s efforts to accelerate the transition from fossil fuels to cleaner, renewable energy sources. The mine would involve extraction of the silvery-white metal used in electric vehicle batteries.

On Monday, the judges didn’t specifically address the claims that the project fails to comply with a new opinion the 9th Circuit issued last year that blocked a copper mine in Arizona based on a more stringent interpretation of the 1872 Mining Law regarding the use of neighboring lands to dispose of waste.

Rather, they more generally deferred to the expertise of the U.S. Bureau of Land Management, which approved the mine in 2021, and the decision by U.S. District Judge Miranda Du in Reno earlier this year to allow construction to go forward even though she concluded the mine was not in complete compliance with the new interpretation of the Civil War-era mining law.

The bureau’s approval of the mine “was not arbitrary, capricious, an abuse of discretion or otherwise not in accordance with” the National Environmental Policy Act, the 11-page ruling said.

The bureau approved the mine in 2021 on an accelerated basis under Donald Trump’s administration. The Biden administration has continued to embrace it in an effort to ramp up U.S. lithium production.

Officials for Lithium Nevada, a subsidiary of the Canadian-based Lithium Americas, say the Thacker Pass mine’s reserves would support lithium for more than 1.5 million electric vehicles per year for 40 years.

Conservationists say the operation will pollute the groundwater and destroy precious habitat for sage-grouse, pronghorn antelope and other species in violation of environmental laws.

Their lawyers had argued that Du illegally exceeded her authority when she refused to revoke the mine’s operation plan in March despite her conclusion that federal land managers had violated the law in approving parts of it.

The 9th Circuit ruling concluded Du applied the proper legal standard and found the bureau’s sole error in approving the project “weighed against” vacating the entire approval of the mine.

Spokespeople for the plaintiffs said after Monday’s ruling they were considering their legal options.

“We all recognize the need for renewable energy, but it can’t come at the cost of making the biodiversity crisis worse,” said Erik Molvar, executive director of Western Watersheds Project.

Government lawyers had said much of the evidence the Western Shoshone and Paiute tribes presented about the sacred nature of the land came after a formal decision had been issued and that none of it clearly established the actual location of the massacre.

The 9th Circuit ruled the bureau acted “reasonably and in good faith” in its consultation with tribes potentially affected by the mine.

Company officials said Monday they were “pleased to see such a decisive ruling” and that construction was continuing.

“We have always been confident that the permitting process for Thacker Pass was conducted thoroughly and appropriately,” Lithium Americas CEO Jonathan Evans said in a statement emailed to The Associated Press.

One independent analyst group said the “brisk” issuance of the ruling so soon after the June 27 oral arguments underscored the significance of what it considered an “important legal victory” for the mine that could become one of the largest lithium-producing operations in the world.

”Opponents could seek further review at the Ninth Circuit or may appeal to the U.S. Supreme Court, though we are skeptical their arguments would fare any better,” Washington-based ClearView Energy Partners said in a note to clients.

Plaintiffs in the case said in emails to the AP that they hadn’t decided whether to appeal.

Great Basin Resource Watch Executive Director John Hadder warned the ruling could set a dangerous precedent.

“Lithium Nevada’s destruction of sage-grouse, pronghorn and other wildlife habitats at Thacker Pass foretells the damage to public lands and the biodiversity loss that the lithium boom in the West will cause,” said Katie Fite, public lands director for WildLands Defense.