Montana's largest coal mine has been indefinitely shuttered by its new owners from the Navajo Nation in a dispute over whether it should be immune from some environmental regulations.
The Navajo Transitional Energy Company said Thursday that the 275-worker Spring Creek Mine near Decker was being shut down while negotiations continue with state officials.
The company is owned by the Navajo Nation but operates independently. It recently bought Spring Creek and two Wyoming mines in a bankruptcy sale.
A company spokesman says state regulators last week demanded that it waive its immunity as a tribal entity.
A Department of Environmental Quality spokeswoman says officials never sought a complete waiver but wouldn't release further details.
The strip mine produced almost 14 million tons (12.7 million metric tons) of coal in 2017.