Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata
called coal seams.
Industry related with the technical and mechanical activity of removing coal from the earth and preparing it for market.
The natural, rocklike, brown to black derivative of forest-type plant material, usually accumulated in peat beds and progressively compressed and indurated until it is finally altered in to graphite-like material.
A black rock formed from prehistoric plant remains, composed largely of carbon and burned as a fuel.