Effect of Stresses and Acoustic Emissions on Gas Permeability of Coal

The effect of stresses and acoustic emissions on the gas permeability of coal was investigated in the field and the laboratory in order to find an estimative method of the practicability of gas drainage. In the field, acoustic emissions and gas emissions during gas drainage drilling were monitored tentatively at some coal mines in Japan and China.In the laboratory, acoustic emissions from coal specimens in addition to gas permeability were measured during the triaxial compression loading in order to interpret the results monitored in the field. Besides, the opening of gas permeation channels in coal was considered on the basis of the experimental results.