Mammoth Mine Explosion. On January 27, 1891, an explosion in the nearby Mammoth No. 1 Mine of the H.C. Frick Coke Company killed 109 coal miners. Seventy - nine of the dead were buried in a mass grave here in St. John's Cemetery. This disaster was the worst one known to that time in a bituminous coal mine in Pennsylvania. It led to state legislation strengthening the program of mine safety inspections in the bituminous fields.

St. John's Cemetery, along Rt. 819, Scottdale, PA, United States