Coal breaker remaining. The sorting by size is particularly important for anthracite coal. In order to burn efficiently, air must flow evenly around anthracite. Subsequently, most anthracite coal is sold in uniform sizes. In the 1910s, there were six commercial sizes of coal (with the smallest size having three subsets): Coal pieces smaller than in size were considered "culm," and unable to be separated from the impurities (and thus useless). The grade of coal ranged from a low of 5 percent impurities for steam or broken coal to a high of 15 percent for pea-size coal and its subsets. Coal breakers were
Coal pollution mitigation to encourage the introduction of coal pollution mitigation and other technologies to reduce environmental impact. Combustion of coal--which is mostly carbon--produces carbon dioxide as a product of combustion. According to the United Nations Intergovernmental Panel on Climate Change, the burning of coal, a fossil fuel, is a significant contributor to global warming. (See the UN IPCC Fourth Assessment Report). For 1 ton of coal burned, 2.86 tons of carbon dioxide is created. Carbon sequestration technology has yet to be tested on a large scale and may not be safe or successful. Sequestered CO may eventually leak up through the ground,