Explanation:

 Among all the type of coal bituminous coal is d most available variety in west bengal.Bituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen or asphalt. It is of higher quality than lignite coal but of poorer quality than anthracite. Formation is usually the result of high pressure being exerted on lignite. Beside lignite ranks 2nd in its availability in the state..