Structural parameters of coals were studied in connection with forecasting rock bursts in coal seams. Samples of bituminous coal and anthracite were analysed in order to determine the character of structural change in coal during metamorphism and its connection with gas bearing properties. It was demonstrated that the relationship between the methane in coal and the concentration of paramagnetic centres, which are directly connected with gas formation in the coalification process, is an indication that gas in coal seams can be determined by the intensity of gas formation during metamorphism.