Coal is an organic matter that is formed from plant debris that was deposited some million years back and that have undergone a process known as coalification. Coalification is a process by which plant debris deposited in a suitable environment is turned initially into peat and subsequently into lignite, bituminous and anthracite which represent the different ranks of coal. Coal is a sedimentary deposit which is formed in the form of horizontal and gently dipping beds which are called coal seams. Run-of-mine coal often contains impurities associated with it. These are inorganic (non-carbonaceous) matter like shale, slate, clay and also pyrite (FeS2) which is formed in marine coal deposit by the reaction of iron sulfate with coal forming matter. Part of these impurities are introduced during mining, while: widening of the openings for introducing machineries when thin bed of overburden exists between coal seams and inclusions while blasting, mucking and transporting the ROM.These impurities reduce coal heating value, leave behind an undesirable ash residue, and increase the cost of transporting coal to market.