RENO, Nev. (AP) — A high-stakes, yearslong legal battle over a huge lithium mine planned in Nevada resumes Thursday with arguments from lawyers for the mining company, the U.S. agency that approved it and the rancher, tribes and conservationists fighting the project.

U.S. District Judge Miranda Du has refused twice over the past year to grant temporary injunctions sought by tribal leaders who say the mine site is on sacred land where their ancestors were massacred by the U.S. Cavalry in 1865.

But Thursday’s hearing in her Reno courtroom marks the first on the actual merits of the case and will set the legal landscape going forward with a new twist after the 9th U.S. Circuit Court of Appeals upheld a ruling in Arizona that voided federal approval of a copper mine.

That potentially precedent-setting decision raises questions about the reach of the Mining Law of 1872 and could have a bearing on disposal of waste rock at the lithium mine in the high desert 25 miles (40 kilometers) south of the Oregon line, the largest proposed in the nation.

Lithium Nevada Corp. and the U.S. Bureau of Land Management say the project atop an ancient volcano is critical to meeting growing demand for lithium to make electric vehicle batteries — a key part of President Joe Biden’s push to expedite a transition from fossil fuels to renewable energy.

Nevada rancher and conservation groups say it will destroy dwindling habitat for sage grouse, Lahontan cutthroat trout, pronghorn antelope and golden eagles.

“Along with adjacent Oregon wild lands, it constitutes one of the last big blocks of the sagebrush sea free of development,” said Katie Fite of Wildlands Defense, one of the plaintiffs suing to block the Thacker Pass project about 200 miles (321 kilometers) northeast of Reno.

“We need a smart energy future that transitions our economy from fossil fuels to renewables without sacrificing rare species in the process,” said Greta Anderson, deputy director of the Western Watersheds Project, which also petitioned in September for protection of a tiny, nearby snail under the Endangered Species Act.

The BLM fast-tracked the project’s approval during the final days of the Trump administration in 2021. The Biden administration continues to embrace the mine as part of the president’s “clean” energy agenda intended to combat climate change.

Demand for lithium is expected to triple by 2030 from 2020 and Lithium Nevada says its project is the only one on the drawing board that can help meet the demand.

Opponents who first sued in February 2021 to block the mine want Judge Du to nullify BLM’s approval of the plans. Company officials and government lawyers want her to uphold them so construction can begin this year.

In addition to the cultural and environmental concerns about the potential impacts, the new 9th Circuit ruling halting the Arizona mine in July and subsequent refusal to consider its decision in September is on the mind of the judge in Nevada.

Du said in a court order ahead of Thursday’s hearing she is “interested in the extent to which (that case) controls the outcome of this case.”

The San Francisco-based appellate court upheld the Arizona ruling that the Forest Service lacked authority to approve Rosemont Copper’s plans to dispose of waste rock on land adjacent to the mine it wanted to dig on a national forest southeast of Tucson.

The service and BLM long have interpreted the Mining Law of 1872 to convey the same mineral rights to such lands.

The 9th Circuit agreed with U.S. Judge James Soto, who determined the Forest Service approved Rosemont’s plans in 2019 without considering whether the company had any mining rights on the neighboring lands. He concluded the agency assumed under mining law that Rosemont had “valid mining claims on the 2,447 acres it proposed to occupy with its waste rock.”