History of anthracite coal mining in Pennsylvania History of anthracite coal mining in Pennsylvania There are two types of coal found in Pennsylvania: anthracite (the “hard coal” found in Northeastern Pennsylvania below the Allegheny Ridge southwest to Harrisburg; also called “stone coal”, “rock coal” in the 1800s) and bituminous (“soft coal”, found west of the Allegheny Front escarpment). Anthracite coal is a natural mineral with a high carbon and energy content that gives off light and heat (produced energy) when burned, making it useful as a fuel. It was possibly first used in Pennsylvania as a fuel in 1769, but its real history begins with a documented
Heat treating decarburization, because the iron oxide keeps oxygen in contact with the decarburization zone even after the steel is moved into an oxygen-free environment, such as the coals of a forge. Thus, the carbon atoms begin combining with the surrounding scale and slag to form both carbon monoxide and carbon dioxide, which is released into the air. Steel contains a relatively small percentage of carbon, which can migrate freely within the gamma iron. When austenized steel is exposed to air for long periods of time, the carbon content in the steel can be lowered. This is the opposite from what happens