A conservation group is asking a federal judge to void a coal lease awarded to a central Montana mine by the U.S. Bureau of Land Management.
An attorney for the Northern Plains Resource Council said in Wednesday's lawsuit that federal officials failed to consider the damage the underground mine is causing to surface landowners.
The lease on an estimated 60 million tons of coal in Musselshell County was awarded to Signal Peak Energy in 2012.
Ranchers operating above the mine have seen large fissures in the ground that they say is caused by coal removal. The lawsuit says the changes to the landscape put water supplies for livestock at risk.
Bureau of Land Management spokeswoman Mel Lloyd says the agency will review the lawsuit with its attorneys.