US judge rules Lithium Americas may excavate Nevada mine site The Thacker Pass lithium mine is host to the largest known lithium resource in the US. Image from Lithium Americas. A U.S. federal judge has ruled that Lithium Americas Corp may conduct excavation work at its Thacker Pass lithium mine site in Nevada, denying a request from environmentalists who said the digging could harm sage grouse and other wildlife. The ruling marked a rare win for a U.S. critical minerals project as environmental groups increasingly pressure courts and regulators to block mining projects, even if they produce metals key to building electric vehicles.