A novel concept of enhanced gas recovery strategy from ventilation air methane in underground coal mines – A computational investigation

Abstract Large amount of methane are released in the mining face area during active mining operation. To maintain safe working condition in the mining face and to maximize the potential usage of methane released from the mining face, an effective methane enhanced gas recovery strategy is essential. This study addresses the air flow and methane dispersion in the mining face and strategies to mitigate and enhance methane gas recovery for energy sources by using ventilation system. The investigated strategies involve installation of a suction duct and combination of brattice and suction duct. The aim is to collect methane-rich ventilation air via additional exhaust (suction) duct rather than disperse it and collect it later from the main exhaust shaft. Computational fluid dynamics (CFD) approach is utilized to investigate and examine the effectiveness of these strategies which will be evaluated in term of methane concentration in the mining face and at the outlet of suction duct. The effect of suction duct height, setback distance and suction velocity on the methane mitigation and recovery are also evaluated. The result indicates that suction-brattice configuration results in better methane control but yields lower methane concentration collected at the suction duct outlet. Among the studied parameters, suction velocity has significant influence while suction duct height and setback distance have marginal effect. The proposed strategies are potential to be applied in underground coal mine for methane mitigation and recovery.