Coal breaker the United States in the state of Pennsylvania (where, between 1800 and the mid-20th century, many of the world's known anthracite reserves were located). At least one source claims that, in 1873, coal breaking plants were found only at anthracite mines in Pennsylvania. The first function of a coal breaker is to break coal into pieces and sort these pieces into categories of nearly uniform size, a process known as breaking. The second function of a coal breaker is to remove impurities (such as slate or rock), and then grade the coal on the basis of the percent of impurities
Environmental impact of the coal industry the environment. While these substances are trace impurities, enough coal is burned that significant amounts of these substances are released. During combustion, the reaction between coal and the air produces oxides of carbon, including carbon dioxide (CO, an important greenhouse gas), oxides of sulfur (mainly sulfur dioxide, SO), and various oxides of nitrogen (NO). Because of the hydrogenous and nitrogenous components of coal, hydrides and nitrides of carbon and sulfur are also produced during the combustion of coal in air. These include hydrogen cyanide (HCN), sulfur nitrate (SNO) and other toxic substances. SO and nitrogen oxide react in the atmosphere