Service truck operator Phillip Gustafson, 38, was working June 8 at Taft Coal Sales and Associates’ Choctaw mine in Walker County. He was refueling a diesel track-mounted highwall drill and placing a fuel nozzle into the tank of the unit when an ignition occurred.

A fire erupted as a result, and Gustafson was fatally injured after being engulfed in flames.

The worker’s 7.5 years of experience were all gained at Choctaw, conducting his primary duties.

The US Mine Safety and Health Administration said in its final report that a pre-operational check of the involved equipment was conducted by the victim as well as the evening shift drill operator. While the written record was destroyed by the fire, the operator stated that no hazards had been noted.

Investigators also reviewed the drill hydraulic system to determine if a rupture could have provided the initial fuel for the fire.

“An extensive examination was conducted on all … circuits, as well as other miscellaneous circuits,” the agency noted.

“The examinations did not reveal any ruptures that could have allowed hydraulic oil to provide fuel for the initial fire.”

Federal officials developed four potential scenarios based on interviews and physical evidence. Of those, the most likely scenario involved the accidental spray of diesel fuel onto the hot surfaces on and around the engine and hydraulic pump area just before fueling, resulting in vaporization and ignition.

“The flammable vapors were present near the engine turbocharger at about the same time the nozzle was being inserted into the tank neck,” MSHA said.

“The turbocharger ignited the vapors creating an explosion/flash fire, which in turn caused the victim to recoil, while still holding the nozzle in the on position, allowing additional fuel to be discharged onto the engine area and him, engulfing him in flames.”

To rectify the root cause of inadequate work practices, the mine operator modified its fueling procedures to require highwall and rock drills to be shut off before fueling. Operators at the mine were trained on the new fueling procedures and the approved CFR 30, Part 48 training plans were updated to reflect the additional procedures.

The producer is planning further modifications to the fueling system process to take the service truck operator out of proximity to potential ignition sources, which will also minimize the potential for accidental fuel discharge.

Gustafson’s death was the 37th of 48 fatalities in the US coal industry in the 2010 calendar year.

The 105-worker Choctaw bituminous mine is owned by large Alabama producer Walter Energy.