Petrographic classification and codification of Indian coals

A petrographic classification and codification of Indian coals has been proposed in which the cols have been grouped into ten ‘coal types’ on the basis of vitrinite content, eight ‘genera’ on the basis of exinite content and ten ‘reflectance numbers’ on the basis of mean maximum reflectance of vitrinite. These parameters have further been codified so as to enable the petrographic characteristics of a coal to be expressed by a three figure code number-the first and second figures of which represent vitrinite and exinite contents respectively while the third figure suggests the rank of the coal on the basis of reflectance of vitrinite. The proposed classification and codification has been found to be suitable for grouping Indian coals with particular reference to their geological occurrences as well as for their technological usages.