Petrographic and geochemical characterization of coal from Talcher coalfield, Mahanadi Basin, India

Abstract

In the present study an attempt has been made to characterize the coals of Talcher coalfield employing petrographic and geochemical techniques on a large number of coal samples. Pillar coal samples were collected from all the six workable coal seams, which occur in the Karharbari (Seam-I) and the Barakar (Seams II, III, IV, V and IX) formations. The petrographic study shows that these coals are vitrinite rich followed by the liptinite and inertinite groups. The quantitative maceral analysis suggests that the concentration of vitrinite is higher in the Karharbari coals as compared to the Barakar coals while the amount of liptinite is greater in the coals of Barakar Formation. The concentration of inertinite is almost same in the coals of these two formations. The microlithotype analysis shows the dominance of vitrite, clarite, vitrinetite and inertite. The concentration of liptite, clarodurite, duroclarite and vitrinertoliptite are insignificant. The mean vitrinite reflectance of the Karharbari coal is higher than that of the Barakar coals. The vitrinite reflectance values rank the Karharbari coal as High volatile Bituminous ‘C’ to High Volatile ‘B’ Bituminous and the Barakar coal as Sub-Bituminous ‘A’ to High Volatile Bituminous ‘C’. The study reveals that the Talcher coals have originated under wet moor with intermittent moderate to high flooding and the fluctuation in the water table has ultimately resulted in the variation in the petrographic and chemical contents of the two coals.