Coal and Lignite Resources of India: An Overview

Coal resources of the country belong to two stratigraphic levels and basinal set up viz., Permian sediments in intra-cratonic lower Gondwana basins, and Early Tertiary near shore basins and shelf having mainly peri-cratonic set up. Major part of coal resources within the Gondwana basins that are preferentially located in the eastern and southeastern part of the country. The Tertiary coal constitutes only a small portion of the total coal resources and mostly occurs in the north-eastern states. Main deposits of lignite of Tertiary age are located in the southern states with minor deposits in the western states. The Gondwana basins of Peninsular India have certain characteristics in terms of their distribution pattern and mode of evolution. These occur as conspicuous rectilinear belts of basins. The disposition of these is mostly controlled by the Precambrian crustal structures. The Gondwana coal basins in particular are generally located along present river valleys after which they are usually named. The Permian coal basins of Lower Gondwana developed as failed rift-related intra-cratonic basins, which mainly housed fluviatile and fluvio-lacustrine sediments. Initially these basins were embryonic in dimension where sedimentation commenced with deposition of glacial and glaciogene fluvio-lacustrine sediments. These were followed by essentially fluvial sedimentation in the basins that grew in dimension mainly by extensional faulting parallel to the rift trend creating half-grabens that formed different sub-basins that formed different sub-basins within a master basin belt. Coaly facies were at their acme within the Barakar coal-measure of early Permian age and developed only locally within the underlying Karharbari and the overlying late Permain Raniganj Formation. The Karharbari sedimentation at places was also under near shore environment as revealed by the presence of marine beds at Umaria and Daltonganj coalfields.