Coal is a burnable dark brown or black rock found underground and mainly contains carbonized plant matter. This is extracted either by shaft mining or open pit mining.
There are different types of coal which include peat, lignite, bituminous coal, sub-bituminous coal, steam coal, graphite and anthracite. The grouping of coal is mainly based on volatile content but criteria for the same may change with nations.
Coal is mainly used as a fuel for producing heat and electricity through combustion. It is used for deriving coke which serves as a fuel and also as reducing agent for furnaces. Syn gas can be produced from coal classification which can be further converted to diesel and gasoline. Coal can be transformed into several synthetic fuels via processes like liquefaction. It is extensively used as feedstock for producing chemicals.