Parameters of methane condition during phase transition at the outburst-hazardous coal seam edges

The authors analyze phase equilibrium of gaseous methane and crystalline hydrate particles in coal pores, considering absorbed heat during phase transition. It is shown that the crystallohydrate-gaseous methane phase equilibrium in small pores can be nonsteady; i.e., on deviation from the phase equilibrium curve, the methane condition parameters change and, as a consequence, increase the deviation. Instantaneous dissociation of crystallohydrates builds up methane pressure, which intensifies outburst hazard and affects the outburst gas balance.