Pennsylvania bituminous (“soft”) and anthracite (“hard”) coal, the Commonwealth’s most abundant energy resource, has served the nation well. Historically, coal was the fuel of choice for transportation and other steam-powered applications and was essential, in the form of coke, for the production of steel. Today, coal is used mostly by utility power plants for the generation of electricity—sometimes referred to as “coal by wire.” Other significant uses of coal include synfuel production, steel making, heat and power for other industrial plants, and residential and commercial heating. Some of the largest, most modern and productive underground coal mines in the United States are located in southwestern Pennsylvania. The coal industry will continue to play a vital role in Pennsylvania’s economy for decades to come.
"Coal is a rock composed of the altered and compressed remains of plant material which, by burial, escaped decomposition and which occurs as layers within the surface rocks of the earth. Coal contains, stored within itself, the elements and sun's energy that these plants collected into their own constituent compounds when they grew many millions of years ago. When coal is burned these stored elements and energy are released just as when a piece of wood is burned.
Coal is burned to generate our electricity and to make our iron and steel. It is refined to make medicines, plastics, synthetic rubber, fertilizer, cosmetics, food products, paint, dyes, and even the fibers of our clothes."
—excerpt from Edmunds, W. E., and Koppe, E. F. (1968), Coal In Pennsylvania, Pennsylvania Geological Survey Educational Series 7