A US federal judge will rule by September 3 on whether to grant a request from Native Americans to temporarily block Lithium Americas Corp from excavating its Nevada mine site, which would become one of the country's biggest sources of the electric-vehicle battery metal.

A ruling for the Native Americans could signal the court may block the entire project, which was approved by the outgoing Trump administration in January.

Chief Judge Miranda Du of the federal court in Reno, Nevada, held a Friday hearing to determine whether archaeological digging at the Thacker Pass site should be blocked while she considers the broader question of whether approval should have been granted in the first place.

Tribal members say the mine would disturb ground that contains ancestral bones. The digging itself is required by federal statute to determine whether the land holds any historical artifacts.

The Vancouver-based company and the US Bureau of Land Management (BLM), which controls the land, say the tribes did not participate in the mine permitting process when asked and did not share their beliefs about the land until earlier this summer, after the project was approved.

"BLM's outreach efforts ... have been reasonable and in good faith," Arwyn Carroll, a BLM attorney, told the hearing. "The tribes never told BLM that Thacker Pass could be this type of site."

Attorneys for the tribes say regulators did not work hard enough to contact every tribe that could have a connection to the site, especially amid the pandemic.

Du, an appointee of former President Barack Obama, last month rejected a request from environmentalists to prevent digging, but then allowed tribes to essentially make the same request.

Du gave little hint which way she may rule, though several times asked how Native American artifacts would be handled if discovered.