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Coal is a readily combustible black or brownish - black sedimentary rock. It is composed primarily of carbon along with variable quantities of other elements, chiefly sulfur, hydrogen, oxygen and nitrogen.
Coal was formed from plant remains through pressure, time and biodegradation to create a solid material of carbon.
Coal, a fossil fuel, is the largest source of energy for the generation of electricity worldwide. Coal is extracted from the ground by mining, either underground or in open pits. |
