Coal is one of the important primary fossil fuels and a source of energy. It is a solid carbon-rich material, sedimentary deposit composed predominantly of carbon that is readily combustible. Its color is black or brownish-black. Coal has a composition that consists of more than 50 percent by weight and more than 70 percent by volume of carbonaceous material. Grades / type: Type 1 to Type 7 Gross Calorific Value (6,500 - 6,300 - 6,000 - 5,800 - 5,500 - 5,300 - 5100 and below) Applications - Electricity and heat generation - Industrial purposes - Metal refining