Table 2: Estimations for different types of coal based on formation

The Gondwana coal belongs to the carboniferous period. It is found in the Damodar, Mahanadi, Godavari, and Narmada valleys. Raniganj, Jharia, Bokaro, Ramgarh, Giridih, Chandrapur, Karanpura, Tatapani, Talcher, Himgiri, Korba, Penchgati, Sarguja, Kamthi, Wardha valley, Singreni (A.P.) and Singrauli are some of the important coal mines of the Gondwana formations. The Jharguda coal mine (Chhattisgarh) is the thickest coal seam 132 meters of the Gondwana period, followed by the Kargali seam near Bokaro belong to the Gondwana period. The detail of state-wise geological resources of Gondwana coal is given below in table 3.