Wednesday, August 22, 2007

West Elk Mine Thermal Event

The Mountain Coal Company's West Elk Mine is located near Somerset, Colorado. About 300 persons are employed in the multiple seam coal mine. In 1999, 7.3 million tons of coal were mined with two continuous mining development units and a single retreating longwall unit.

The mine fire at the West Elk mine has been extinguished by flooding the suspected fire area with water. MSHA Technical Support staff assigned to the mine were withdrawn on May 8 to complete gas monitoring operations. Remote concrete plugs at the locations identified on the map have served as bulkheads to flood the area. The estimated location of the water shore line is identified on the map. The water pumping rate into the fire area was increased to 600 gallons per minute, and bentonite was injected into the water near the remote plugs to help fill fissures where water may have been leaking from the dammed area. These actions caused the water level to rise rapidly which finally quenched the heating. With the water level roofed in much of the area of the fire, fire gases had fallen to the lowest levels since the thermal event began. Typical concentrations on April 14 from Borehole T within the sealed area were : hydrogen 44 ppm, carbon monoxide 340 ppm, ethylene 0 ppm, and methane 0.24 percent. Longwall shield recovery was completed on April 21, and the longwall equipment was being installed on the new face at the time of this report. The company plans to be back into production following additional preparation work sometime in June 2000. The recovery operation included the drilling of 43 boreholes and the installation of 17 remote plugs from the surface. The overburden depth (cover) in the sealed area ranged from approximately 1250 to 1350 feet. The mine fire recovery is considered the most successful remote sealing and flooding project in the United States to date. It featured the extensive use of downhole cameras and temperature probes to determine physical conditions in the inaccessible areas which provided information critical to decision making by mine officials.