According to local newspaper the Gillette News-Record, 39-year-old Frances Cope was working on a rubber-tired dozer at Alpha Coal West’s Eagle Butte mine in Campbell County last Saturday evening at about 9.30pm.

The machine landed on its back end, then flipped over and came to rest on its roof.

Mine spokesperson Steve Laird told the paper the fall was broken by slough at the bottom of the bench.

“It is fairly soft and it extends up the wall… and there is a lot of it,” he said, noting that Cope was wearing a seat belt.

However, he added that the worker was trapped in the dozer in a remote section of the mine, so there were no eyewitnesses to the incident.

The impact of the landing disabled her radio communication, so she signaled for help with a flashlight.

After being extracted from the dozer, Cope was transported to a medical facility, treated and released, the News-Record said.

Eagle Butte officials told the paper an internal investigation was underway.

In September, Eagle Butte marked two years without a lost-time accident. During that period, the operation produced 44 million tons of coal and put in more than 1 million man hours.

Nearby sister mine Belle Eyre also celebrated a safety milestone at the time, one year without a lost-time incident on more than 770,000 man hours worked and 28Mt produced.

After the merger with Foundation Coal last year, Alpha Natural Resources now controls 61 mines and 14 coal preparation facilities in Appalachia and the Powder River Basin.