ABSTRACT
The various classifications of coal have been given by different geologists. Most classifications are based upon some property of coal which varies with increasing maturity or rank of coal. The systems of classification fall into two categories:
Scientific Commercial
For scientific classification, the property used is the ultimate analysis which gives the elementary composition of coal in terms of percentages by weight of the elements present, viz., carbon, hydrogen, oxygen, nitrogen and sulphur. Regnault was the first to give a satisfactory classification in 1837. Later, Gruner in 1874, Gruner-Bousquet [24] in 1911, Grout [25] in 1907 and Ralston [26] in 1915 have modified the classifications. In 1900, C.A.Seyler [27] proposed another classification.
