Application and practice of high level gas drainage technology in low gas coal seam working face

Disallowed gas concentration or abnormal emission at top corner often occurred in high gas working face.The relative gas emission was only 2.93 m³/t of TunBao coal mine M5 coal seam，because of the affection of adjacent coal seams and left coal in the gob，the disallowed gas concentration accident occurred several times during the coal production at the working face top corner and result in serious consequences.In order to completely solute the gas hazards problems，and considered the actual situation of the coal mine，the feasibility of gas extraction of 1153 fully mechanized top coal caving working face was evaluated，the necessity and feasibility of gas drainage of the gob were determined.Two technical methods (high-level borehole method and underground pipe method of gob gas suction) were proposed，after technical and economic comparison，high-level borehole gas suction was determined.According to field practices，the gas concentration in the pipeline was stable，disallowed gas concentration accidents no longer happened.The parameters of the gas drainage in the gob under such kinds of the geological conditions were scientific and reasonable，it’s effective technical measures to control the mine gas by high level drilling gas drainage.