BILLINGS, Mont. -

The Custer National Forest has approved Stillwater Mining Co.'s plan to drill core samples to evaluate whether it's feasible to expand its Stillwater platinum and palladium mine to the east.

The Beartooth Ranger District on Monday authorized Stillwater Mining to drill at eight sites in the Beartooth Mountains about five miles southwest of Dean. Drill rigs could be operated at up to three locations and up to five drill holes could be drilled at each site. Drill rigs will be operated 24 hours a day, seven days a week through October. Up to 12 people could be working at the sites.

The Forest Service is not authorizing any road building and requires the company to reclaim any areas it disturbs. The Forest Service has not authorized any mining.