The Mine Safety and Health Administration (MSHA) issued its investigative report into the explosion at the Willow Creek Mine, an underground coal mine located in Carbon County, Utah, that claimed the lives of two miners and injured eight others.
MSHA investigators determined that the ventilation system at Willow Creek did not adequately dilute concentrations of methane gas, which was ignited in a series of four explosions within a 30-minute period on July 31, 2000 when the accident occurred.
"This report provides the mining industry with vital information in order to assist in preventing another such mining disaster," said David Lauriski, MSHA administrator. "Hopefully, the facts we have learned here will prevent such occurrences in the future."
The report says that, just before midnight on July 31, 2000, a series of four explosions occurred underground on the longwall mining section.
The most likely cause of the first explosion was an ignition of methane gas caused by falling rock in the worked-out area of the longwall panel. (Falling rock in the worked-out area is a normal, expected event in the longwall mining process). A fire-ensued.
Miners, believing that the forces they felt were the result of a massive roof fall in the worked-out area, began to fight the fire.
Fire fighting efforts were not successful and conditions worsened in the face area. Hydrocarbons present in the mine caught fire, igniting explosive concentrations of methane, according to the report.
The investigation determined that two fatalities occurred as a result of the second and third explosions and that fire caused by the initial explosion provided the ignition source for the subsequent explosions.
The injured and the deceased miners were brought to the surface by mine rescue teams by 4 a.m. Because the fire appeared to be gaining intensity, it was decided to seal the mine. All surface openings were sealed by approximately 10:30 a.m. on Aug. 1, 2000.
The Willow Creek Mine has not been reopened.
An earlier accident involving a fire occurred at the Willow Creek Mine on Nov. 25, 1998, during retreat of the mine''s initial long wall panel. All miners were evacuated safely during that incident and the mine was sealed at the surface.
Recovery efforts continued until Nov. 15, 1999, when the mine returned to normal operations until the July 31, 2000, explosion.
by Virginia Sutcliffe-Foran