Mine Safety and Health Administration Coal Mine Safety and Health Report of Investigation: Surface Impoundment Facility Underground Coal Mine. Noninjury Impoundment Failure/Mine Inundation Accident, October 11, 2000. Big Branch Refuse Impoundment, I.D

摘要

In the early morning hours of Wednesday, October 11, 2000, a breakthrough of slurry (fine coal refuse and water) occurred from the sixty-eight acre impounding area of Martin County Coal Corporation's (MCCC) Big Branch Refuse Impoundment which inundated the underground active mine workings of MCCC's 1-C Mine. The breakthrough occurred a few minutes after a belt examiner, who was performing a preshift inspection, exited the 1-C Mine. The slurry from the impoundment ultimately breached two underground sealed areas of the active mine and subsequently exited the mine at two drift openings of the 1-C Mine: the South Mains Portal and the No. 2 North Portal. In addition, a relatively small volume of water exited the mine near the Big Branch Punch Out. The outflow from the impoundment was stopped by using dozers to push spoil mixture from above the impoundment into the area where the breakthrough had occurred. An estimated 306 million gallons of slurry flowed from the impoundment into the mine, causing the impoundment pool level to drop an average of 14 feet. The released volume represented 22 percent of the volume of slurry impounded above the 1-C Mine. The flow of slurry out of the mine resulted in flooding and downstream 'black-water' contamination of Wolf Creek and Coldwater Fork. No fatalities or personal injuries resulted from the breakthrough or mine inundation; however, extensive environmental damage occurred in these waterways and successive downstream areas. MSHA's investigation of the accident included the following: interviews of past and present MCCC employees, contractors, and persons living along the affected streams; and a comprehensive geotechnical evaluation of the breakthrough area.