Micropores of fossil coals at the stage of metamorphic transformations of coal seams

Abstract The change in the volume of micropores as the influence of metamorphic processes increases is ambiguous. During the transition from low-metamorphosed coals to an average degree of metamorphism, a slight reduction in the volume of micropores occurs. With further strengthening of the influence of metamorphic processes, the volume of micropores increases. An analysis of the correlation between the results of the study of the yield of volatile substances in coal from the Donetsk and Lviv-Volyn basins showed that the criterion of metamorphism, the yield of volatile substances during thermal decomposition of coal without air access, only indirectly characterizes the degree of metamorphic transformations of the coal seams. A relationship has been established between the micropore volumes and the yield of volatile substances. The formation of the main volume of micropores at the stage of metamorphic transformations of coal seams has been proven. The results of the research allow us to propose improvements to the regulatory framework for predicting the hazardous properties of coal seams during mining operations.