Coal Facts

COAL" is the general term for the rocks formed from the fossilled remains of fresh water plants in dense swamps or logs. When the plants died, they fell into the water where they were soon engulfed in the black, oxygen-deficient mud. Here they were protected from further decay & did not rot away. The mud itself was largely made of bacterially decomposed vegetable matter subsequent burial beneath sand or mud compressed or consolidated the planty layer, driving out water & other volatile substances. (The vegetable matter underwent a series of changes as this proceeded). The most of World's coal beds were deposited millions of years age in warm, humid regions. They have since been compressed by the weight of overburden or by earth movements to less than 1/20th of the thickness of the original deposit.

From the view of value as fuel, the coals are classified according to the degree of change that they have undergone. With greater compression the vegetable material is reduced in volume becomes blacker, harder, more brittle and the individual plant fragments become more difficult to distinguish. Such changes are said to indicate and increase in rank. In other terms, rank refers to the MOISTURE, VOLATILE MATTER and FIXED CARBON in the coal and it increases with the proportions of FIXED CARBON present. Normally, the coal is of two types, Coking and Non-Coking (Anthracite, Bituminous, Sub-bituminous and Lignite).