Petrographic Characters of Selected Gondwana Coalsof India

摘要

The Permian coals of India are referred to as Gondwana Coals, named after indigenous“Gond” tribe of eastern India. These coals are significant source of energy for rapidlygrowing economy of India. The coals represent 99% of thermal and coking coalresources of India, with an estimated 21 billion tonnes of resource for the population ofapproximately one billion people.The Gondwana coals were deposited under a set of geological, biological and chemicalenvironments which provided unique petrographic characters, somewhat similar to thePermian coals of Australia. Most of the Permian coal basins of India are elongate, halfgraben structures located in Damodar, Son-Mahanadi, Pench Kanahan and the Pranhita-Godavari valleys of east, east central and south central parts of India.The coals have subdued lustre due to the presence of fine laminations and associationsof finely dispersed mineral matter within dull and bright lithotypes. The vitrinite andinertinite group of macerals are dominant with minor macerals of exinite group. Thetrace elements in the coal of environmental concern are categorised as major, moderate,minor and the radioactive like thorium and uranium. The petrographic characters andsedimentological studies of inter seam sequences suggest that the Gondwana coals weremostly deposited in fluviatile environments.