The federal Mine Safety and Health Administration is testing new operating procedures at Murray Energy's Tower Mine near Price to enhance miner safety.

The company said Wednesday the 170 miners laid off when the mine's operations were suspended in August should be back to work in early January.

Major changes underground include the addition of video monitoring cameras, pressure monitors, additions to shields that would separate miners from bursting or falling debris and increased distances between miners and longwall mining machines.

Murray closed Tower Mine in August to complete safety-related work after the fatal collapses at its nearby Crandall Canyon Mine earlier that month. MSHA has been involved with the company since then, working on operational changes designed to make conditions safer in mines prone to "bounces," or seismic events in which pressure causes sections of coal inside a mine to burst or collapse.

Such a bounce at Murray Energy's Crandall Canyon Mine near Huntington fatally trapped six miners, and a second bounce killed three rescuers.

"After Crandall Canyon, we just felt we needed to take a look, based on the devastation we saw there, which was unexpected to any of us," Kevin Stricklin, MSHA's administrator for Coal Mine Safety and Health program, told the Deseret Morning News on Tuesday.

The retreat-mining technique at Crandall Canyon in Huntington Canyon, which remains closed, differs from the longwall operation at the Tower Mine north of Price. The similarity that has MSHA's attention is that both mines are extremely deep.

Deep coal mines are not unique, but mountain conditions in Utah and Colorado are more prone to bounces than Eastern mines.

"Those don't seem to be as bump prone," Stricklin said. "There are mines in Alabama under 2,500 feet of cover, but the overburden above them isn't mountainous — it's basically flat."

Mountaintops in western mines, on the other hand, may rise 1,000 to 3,000 feet above the operations underground. The geological difference "is what may play a role in this," Stricklin said.

There are at least 80 mines at depths similar to Crandall Canyon and Tower, Stricklin said. MSHA investigators visited 15 deep, Western mines while researching the new operation plan for the Tower Mine.

At Tower, mine operators have removed 19 shields from each side of the longwall working face and are adding protective sprags or plates to the shields "that will protect the workers if a bump were to occur in that area. Hopefully this sprag will catch (debris) before it would reach workers," Stricklin said.