According to the Mine Safety and Health Administration, maintenance foreman Jamison Ward, 28, was working at Signal Peak Energy’s Bull Mountain operation near Roundup the morning of March 24 with a group of other miners attempting to free the longwall’s face chain conveyor.

After an access door was opened at the location, the chain suddenly began to move, entangling Ward’s foot as it moved 15 feet and 3 inches.

The movement severed Ward’s right foot above the ankle and he also suffered a compound fracture to his left leg below the knee, the report said.

No one else was injured in the incident. Ward was transported by helicopter to a local medical facility; local media has reported that the worker has since been released.

Local paper the Billings Gazette quoted Signal Peak officials as saying late Monday that the company had not yet seen MSHA’s report and could not comment.

The agency reportedly said the event would not have a bearing on the mine’s now-closed potential pattern of violation review because that designation had been for a specific time period. Bull Mountain was on MSHA’s target list last November.

The Signal Peak mine, a longwall operation in Musselshel County, employs about 200 workers. It reopened as a rehabilitated operation in September 2009 following a $US400 million investment by the Boich Group and FirstEnergy.