Petrology of Coal, Burnt Coal and Para Lava from Singrauli Coalfield, M. P. & U. P

Extensive drilling operations carried out by the Geological Survey of India and the Indian Bureau of Mines, in the north-eastern portion of Singrauli coalfield, M.P. and V.P., have revealed the existence of several thick and persistent coal seams, named as Kota, in the Karharbaris, Turra and Purewa from the bottom, in the Barakars, and Jhingurdah Top and Jhingurdah Bottom in the Raniganj formations. Petrological studies of the coals representing these seams in cores and from the quarry faces, have been carried out.

The Karharbari and Barakar coals are composed of mainly durite, 'intermediates', and fusite, while the Raniganj coals are essentially vitrinite-rich, being composed of a greater proportion of vitrite, clarite and the' intermediates' than durite and fusite. The mineral matter is thoroughly disseminated in the organic layers, and it is doubtful if mechanical washing methods can improve the quality of coal. The petrographic composition is also unfavourable for making metallurgical coke. The sporinite content is quite high and may be useful for hydrogenation.

The Singrauli coals are similar in petrographic composition to the coals of the adjacent coalfields of Son valley basin. It is also inferred that the Singrauji basin formed a part of the large spread of the Gondwana sediments from Talcher in the east to Singrauli in the west, forming the Son-Mahanadi basin.

The burnt coal occurs at the expected outcrop position of the Purewa seam in asso. ciation with para lava-fused Barakar sandstone. The presence of cristobalite indicates that temperatures up to 1300°C were reached during spontaneous combustion of the coal seam.