Mechanic Clyde Dolin, 57, fell about three stories before being transported from the facility near Uneeda, West Virginia to Boone Memorial Hospital where he was pronounced dead.
Dolin had 39 years experience in the coal industry including 13 years at the Liberty plant.
Independence Coal president Eric Salyer said Dolin had integrated thoroughly into the West Virginia-based miner’s workforce.
“All of us are saddened by the loss of our friend and co-worker Clyde Dolin,” he said.
“He was a bit of an institution here as he had long service at the plant under its various owners. We will miss him.
“Our thoughts and prayers are with his family in this time of sorrow."
Independence says it has operated the plant since 1994 without a fatal accident.
Federal safety authorities have not immediately responded.
The tragedy marks the eighth US coal fatality of 2012 and the second under Alpha Natural Resources.
In March, operations were halted at Alpha’s Kingston No. 2 coal mine in Fayette County, West Virginia when a rib rolled on 34-year-old Jeremy Sigler who had been operating a continuous mining machine.
Sigler was pronounced dead in hospital after the incident.