united states mine rescue association Mine Disasters in the United States
Cumberland Valley Contractors, Inc. Roof Fall
Middlesboro, Bell County, Kentucky
January 4, 1989
On January 4, 1989, retreat mining in the 001 Section of the CV-2 mine was advancing. As part of this operation, miners extracted coal from the No. 5 pillar, and then from the No. 4 pillar. At about 2:40 p.m. as final cuts were being made to the No. 4 pillar, a sudden roof fall occurred.
Three miners died in the fall.
MSHA investigators determined that the roof of the immediate fall area had contained an undetected "horseback" - a horse-back shaped mass of stone in the roof that is bordered by discontinuities.
While one edge of the horseback had rested on the outby corner of the No. 5 coal pillar, the other edge had rested on the No. 4 pillar. Once the critical outby corner of the No. 5 pillar was removed in violation of the roof control plan, and final recovery of the No. 4 pillar was conducted, the unsupported horseback collapsed.
Another factor contributing to the disaster was missing posts; only five of fifteen timbers required by the roof control plan had been installed. The severity of the accident was also compounded by a failure to restrict persons from a hazardous location during retreat mining.
Historical Summary of Mine Disasters in the United States - Volume II