RENO, Nev. — Opponents of the largest lithium mine planned in the U.S. urged a federal judge in Nevada on Thursday to vacate the U.S. government’s approval of the project until it completes additional environmental reviews and complies with all state and federal laws.

U.S. District Judge Miranda Du said after a three-hour hearing in Reno that she hoped to make a decision “in the next couple months” on how to proceed in the nearly two-year-old legal battle over the Bureau of Land Management’s approval of the mine Lithium Nevada Corp. plans near the Nevada-Oregon line.

Lawyers for the company and the Bureau of Land Management insisted the project complies with U.S. laws and regulations. But they said that if Du determines it does not, she should stop short of vacating the agency’s approval and allow initial work at the site to begin as further reviews are initiated.

Lawyers for a Nevada rancher, conservation groups and Native American tribes suing to block the mine said that should not occur because any environmental damage would be irreversible.

Dozens of tribe members and other protesters rallied outside the downtown courthouse during the hearing, beating drums and waving signs at passing motorists.

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 marked the first on the actual merits of the case. It will set the legal landscape going forward 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 about 200 miles northeast of Reno.