The present paper intends to demonstrate the occurrence of mineral matter as a
deterrent in coal beneficiation as evidenced through coal microscopy. The Indian
Gondwana coals are known for their high ash content due to the presence of inorganic
mineral matter occurring in high concentration. These minerals have been found to
occur as ‘deep intergrowth’, ‘massive impregnation’, ‘superficial mounting’, ‘filling
and depletion of micropores’’, ‘mechanical cavity filling’, and ‘fusinitic cavity
filling’. It is difficult to liberate these mineral matter from coal, creating problems
during their beneficiation. The conventional techniques which are being followed for
the beneficiation of coal in India include hand picking, sizing, blending, pulverizing,
washing, dry cleaning, dedusting, dewatering, drying and briquetting and they are not
instrumental so far. Therefore, some non-conventional means of coal beneficiation
involving microbial treatment or protein enzyme technology may be tried for Indian
coals.