A new tunnel at Revett Minerals’ Troy Mine in northwestern Montana was approved by the U.S. Mine Safety and Health Administration (MSHA) in October.

The tunnel was approved in October and work began at the copper and silver mine in November. 

The Flathead Beacon reported Revett Minerals expects to spend $12 million to dig the new tunnel. Work could take up to a year.

Work at the mine came to a halt late last year after a series of rock falls and cave-ins. The mine laid off 100 workers in May, leaving about 65 employees.

Revett President and CEO John Shanahan said the company has no plans to give up on the Troy Mine.