Simulation of Gas Contamination by Methane in Blind Drift of Coal Mine

As a result of the work, a computer simulation of the methane gas contamination in blind drift coal mine was carried out. The most probable scenarios of the methane gas contamination occurrence in the blind drifts of coal mines associated with violations of the ventilation operation mode are observed: the occurrence of gas contamination in the blind drift at long shutdown of the local ventilation fan; the occurrence of gas contamination at ventilation pipes lag. The analysis of the approaches to modeling of the gas contamination in mine workings was carried out. It was proposed to use computational fluid dynamics software (Fire Dynamics Simulator) for modeling based on the Large Eddy Simulation (LES) turbulence model in the approximation of small Mach numbers (Ma <0.3) (subsonic approximation) and the Deardorff model for calculating turbulent viscosity. Analytical dependencies were formulated. Initial data for modeling were determined: geometric parameters of the blind drift, ventilation and methane emission parameters, and initial conditions. The adequacy of the developed computer model was verified on the basis of experimental data presented in the literature. The calculated and experimental data on the air velocity and distribution of methane concentration in the mine are in satisfactory agreement. The data on the air velocity and methane concentration distribution for the studied scenarios were analyzed. The change in the concentration of methane in the working process was shown, depending on the shutdown duration of the local ventilation fan and when the ventilation pipes lag.