H/C versus O/C atomic ratio characterization of selected coals in Slovenia

Application of the H/C and O/C atomic ratios plotted into the van Krevelen’s diagram is well known approach for chemical characterization of coals, more precisely, of their organicpart. Determination of coals by the two atomic ratios closely relies to their petrographic type as well as to their coalification rank.Elemental data,together with thecoal quality data of 23 coals from the territory of Slovenia are comprised in this study. Coals vary in age from the Carnian anthracite to the Pliocene ortho-lignites, and were deposited in paralic as well as in intermountain basins of different tectonic settings. The highest H/C and O/C atomic ratios are characteristic for the xylite-rich ortho-lignites from Velenje (Pliocene) and Globoko (Pontian), whereas the lowest for the Orle anthracite (Carnian). The Upper Oligocene “hard brown coals” and younger meta- and ortho-lignites treated in this study are typical humic coals. Relatively high H/C ratios are evident for two sapropelic coals, the Se ovlje para-bituminous and the Ra a (Croatia) ortho-bituminous coal, both of the lower Paleogene age. No inertinitic coals are known from our country, however, inertinite macerals are recorded in almost all of them.