Coal is a fossil fuel extracted from the ground by underground mining or open-pit mining (surface mining). It is a readily combustible black or brownish-black sedimentary rock. It is composed primarily of carbon along with assorted other elements, including sulfur. Coal is often associated with the
Industrial Revolution, and remains an enormously important fuel, being the largest single source of electricity world-wide.
World coal consumption is about 5,800 million short tons (5.3 petagrams) annually, of which about 75% is used for electricity production. The region including China and India uses about 1,700 million short tons (1.5 Pg) annually. The USA consumes about 1,100 million short tons (1.0 Pg) of coal each year, using 90% of it for generation of electricity.