GAS EMISSION FROM BROKEN COAL . AN EXPERIMENTAL AND THEORETICAL INVESTIGATION

Deep Soft Coal from Sherwood Colliery in size ranges between 1 2 in. and 200 mesh was brought into equilibrium with methane at pressures of 50, 150 and 300 lb/in2. The rate of release of methane was measured, and the volume V(t) discharged in a time t conformed to the empirical equation: V(t) = A[1 - exp - t t0 1 3 ]. A is the gas content of the coal and to a time constant with to 1 2 proportional to mesh size up to about 1 4 in. A theory on the degassing of a solid containing a crack structure is developed and is compatible with the experimental results. © 1968.