Coal is the product of vegetable matter that has been formed by the action of decay, weathering, the effects of pressure, temperature and time millions of years ago.
Although coal is not a true mineral, its formation processes are similar to those of sedimentary rocks.
Structurally coal beds are geological strata characterized by the same irregularities in thickness, uniformity and continuity as other strata of sedimentary origin. Coal beds may consist of essentially uniform continuous strata or like other sedimentary deposits may be made up of different bands or benches of varying thickness.