Coal & Organic Petrology Lab;
Centre of Advanced Study in Geology;
Banaras Hindu University;
Varanasi 221005;
Uttar Pradesh;
India;
Research & Development;
Oil India Limited;
Duliajan;
Assam 786 602;
India;
Central Institute of Mining and Fuel Research;
Barwa Road;
Dhanbad 826015;
India;