A federal judge has denied a conservation group's attempt to void a 61-million-ton coal lease that was sold to a central Montana mine.

U.S. District Judge Susan Watters said Thursday that the U.S. Bureau of Land Management adequately considered the environmental impacts of mining and decided they would be minor.

The lease in Musselshell County was awarded to Signal Peak Energy for its Bull Mountain Mine in 2012.

The Northern Plains Resource Council claimed in a lawsuit filed last year that federal officials failed to consider damage to landowners from mining.

Ranchers operating above the mine have seen large fissures in the ground they blame on coal removal.