Study of Gas Environment Impacts on Volumetric Coal Matrix Changes

The Outburst can be defined as a sudden release of coal and rock accompanied by large quantities of gas into the underground coal mine workings which represents a major hazard in underground coal mines. Gas drainage has been proven to be successful in reducing outburst hazards by decreasing the in-situ gas pressure. One of aspect of gas drainage from coal seams is coal matrix volume changes. Current study is primarily concerned with experimental studies related to coal volume change (coal shrinkage) under various gas types and pressures. Two types of tests were conducted on each sample, the adsorption test for coal swelling and the desorption test for coal shrinkage. The gases used in the study were CH4, CO2, CH4/CO2 (50-50% volume), and N2. In this research, tests were conducted with respect to volumetric change behavior in different gases and their corresponding comparative results were presented.