Degasification of methane for high methane-emitted coal seam at Mao Khe coal mine - Vinacomin by drilling long borehole

This paper presents a technical solution for reducing methane gas concentration (degasification) caused by a high methane-emitted coal seam at Mao Khe coal mine - Vinacomin. The technique is implemented by drilling a long borehole from the footwall of the roadway into the coal seam and punching small holes along the borehole for gas release. A field study at the longwall level -150/-80 m at Seam 9 of Mao Khe coal mine shows that after the degasification, the gas concentration here is lowered to safety standards. The technique can be used for all coal seams ranked as Class II, Class III, and super-class regarding methane gas, minimizing the risk of methane combustion and explosion.