On July 11, 1902, on this hillside, 112 bituminous coal miners, mostly immigrants, were killed in a gas explosion at Cambria Iron Company's Rolling Mill Mine. It was the first of four major mining accidents in Pennsylvania contributing to the deadliest decade in U.S. underground coal mining history. Along with the anthracite coal strike that same year, the explosion led to the creation of a state Department of Mines in 1903 for the promotion of workplace safety.