On Dec. 1, 1907, an explosion at the Naomi Mine in Fayette City, Pa., killed 34 coal miners.

The Web site of the U.S. Mine Rescue Association provides this summary of what happened:

About 7:45 p.m. Sunday, an explosion of firedamp augmented by coal dust resulted in the death of 34 miners, all that were in the mine. A large quantity of gas must have been ignited. The gas was not detected before anyone was allowed to enter the mine. For some time previous to the explosion, only the working places were being examined before the mine was allowed to be entered.

The cause of the gas being present was an open door. The explosion was caused by an open light or electric arc from the wires. The system of ventilation was fauty having too many doors.

They commenced to sink a shaft but very little progress has been made. It was evident that the fireboss had been trying to get the men together preparatory to leaving the mine. 

The association has also posted front pages of local newspapers with coverage of the disaster.