The modification, which permits continued development of Trapper by its owner Trapper Mining Inc., applies only to its existing federal coal lease. The agency said last week that its evaluation found no significant impact.

The OSMRE was working with an April 30 deadline to release the assessment. Its review was significant, including an October 2015 outreach meeting to solicit comments on the planned EA. The document was subsequently released for public comment from January 25 to February 19, during which time it received 1,148 letters and emails.

The federal approval follows a greenlight by the Colorado Division of Reclamation, Mining and Safety, which had already approved the mine and determined that its reclamation performance bond of $23.4 million was adequate.

The Trapper mine, with a payroll of about 180, can now produce up to 2.6 million tons of coal per year from its previously held leases, which were issued in 1958 and 1962 and cover about 2,423 acres of federal mineral estate. The tracts contain about 19 million tons of recoverable coal.

The operation feeds the Craig Power Generating Station.

The EA and mining plan modification are available to view here.