united states mine rescue association Mine Disasters in the United States
Plateau Mining Company Starpoint No. 1 Mine Roof Fall
Wattis, Carbon County, Utah
August 24, 1979
No. Killed - 4
Retreat mining was underway in the Starpoint No. 1 Mine on August 23 and 24, 1979. This operation involved excavating coal from a pillar located between the No. 3 entry and a caved-in area in the No. 2 entry.
By the evening of August 23, the split had advanced about 20 feet beyond the last row of roof bolts. Nevertheless, the newly exposed roof was not bolstered with additional roof bolts.
On the midnight shift of August 24, the split was lengthened further, with the newest sections of the split featuring a right fork and a left fork. While the split was being advanced, the operator's compartment of the continuous mining machine was moved about 15 feet beyond the last row of roof bolts - a violation of roof support regulations.
By about 10:45 a.m. on August 24 the continuous mining machine had been returned to an area supported by roof bolts, and some timbers had been installed in the split. As additional timbers were being prepared for installation, a sudden roof fall occurred. The collapse killed four miners and seriously injured another.
MSHA investigators determined that the accident had been caused by violations of the roof control plan, including failure to follow the approved cut sequence, and faulty pillar recovery methods that produced excessive widths.
Historical Summary of Mine Disasters in the United States, Volume II