The company said the mock drill at the Gunnison County operation included approximately 200 workers, state officials, local law enforcement emergency responders and other personnel. Of the 12 rescue crews participating, eight were Arch team, two came from neighboring mines Oxbow and Bowie, and two were furnished by the US Mine Safety and Health Administration.

The exercise focused on West Elk, but employees from other Arch operations were involved in other capacities including family and media relations personnel and performance evaluation individuals. MSHA officials were on hand to participate in the entire drill.

"We're sharpening skills we hope we never need to use," Arch Western Bituminous Group president Gene DiClaudio said.

"This all-hands-on-deck, collaborative approach reinforces essential skills that will help us prepare for any situation."

The West Elk mock emergency was designed with various challenges and twists which entered the scenario at different points throughout the day. Arch noted that no one knew in advance the outcome of the situation, which included realistic effects such as smoke.

Crews also had the opportunity to put to work new emergency technology, including underground tracking, real-time mapping capabilities and MSHA's new emergency command vehicle.

"Mine rescue teams are the backbone of emergency response in the mining industry," MSHA assistant secretary of labor for mine safety and health Joseph Main said.

"Since there is no such thing as being overly prepared for a mine emergency, we believe very strongly in the value of these types of exercises."

Arch's lost-time safety incident rate in 2010 was 0.46, the producer’s best ever. The national average is 2.52 incidents per 200,000 employee hours.

Arch has 20 mine rescue teams across its US mines.