In India coal occurs in rock series of two
main geological ages, namely Gondwana, a little
over 200 million years in age and in tertiary
deposits which are only about 55 million years
old. The major resources of Gondwana coal,
which are metallurgical coal, are located in Damodar valley (West Bengal-Jharkhand).
Jharia, Raniganj, Bokaro are important
coalfields. The Godavari, Mahanadi, Son and
Wardha valleys also contain coal deposits.
Tertiary coals occur in the north eastern
states of Meghalaya, Assam, Arunachal
Pradesh and Nagaland.