By Ernest Scheyder

(Reuters) – Two Native American tribes have formally asked a U.S. federal court to prevent Lithium Americas Corp from excavating its Thacker Pass lithium mine site in Nevada, which they say contains their ancestors' bones and should not be disturbed.

The Reno-Sparks Indian Colony and Atsa koodakuh wyh Nuwu/People of Red Mountain filed their preliminary injunction request late Thursday, a filing that had been expected. The tribes say federal regulators did not adequately consult with them before approving the project in January.

The project would become one of the largest U.S. producers of the electric vehicle battery metal. First, though, Lithium Americas needs to conduct archaeological digging at the site in order to catalog historical artifacts. It has not yet obtained necessary permits from federal officials to do so.

The tribes' injunction request essentially asks the court to prevent that archaeological digging even if the company obtains those permits.

"The excavators and shovels could harm the very human remains the archaeologists would be looking for," the tribes said in the filing.

Chief Judge Miranda Du of the U.S. District Court for Nevada asked for responses from Lithium Americas and the U.S. Bureau of Land Management – which manages the federal land atop the lithium deposit – by August 12.

Vancouver-based Lithium Americas and the BLM declined to comment on the filing.

Du denied a similar injunction request last week from environmentalists who argued the project could harm wildlife. Earlier this week, though, the judge allowed the tribes to join the lawsuit to argue their concerns the project could harm historical sites.

Beyond the injunction requests, Du is considering whether former President Donald Trump's administration erred when it approved the entire project in January. That ruling is expected by early 2022.

(Reporting by Ernest Scheyder; Editing by David Gregorio)