Transient States in the Flow of the Air-Methane Mixture at the Longwall Outlet, Induced by a Sudden Methane Outflow

The paper discusses the results of the numerical simulation of a sudden outflow of the air-methane mixture from behind a powered support, for a longwall ventilated by means of the U-type ventilation system. The calculations were performed using the geometrical model of an actual longwall - the I 100 longwall at the „Sośnica” hard coal mine. The steady state of the air flow in the area of the upper corner was discussed, together with the phenomenon of methane seepage from the goaf area in the vicinity of the longwall outlet. Subsequently, the phenomenon of a sudden methane outflow - followed by the ventilation of headings - was introduced into the study. The obtained results confirm the knowledge provided by the mining practice and experience