Non-pillar Mining Practice of One Time Forming Two Tunnels After Wide Cross Section Tunneling in High Gas Mine

Anshun coal mine is a coal and gas outburst mine,the original layout of gas special drainage gateway plan solved the problem of gas exceeding the limit in upper corner and return airway,which had some shortcomings such as slow excavating velocity and coal loss increased due to gas drainage.Combined with the actual conditions of Anshun coal mine,the non-pillar mining practice of one time forming two tunnels after wide cross section tunneling was put successfully at 9106 working face.The technology first excavates a wide cross section tunnel,then the seperation wall will be constructed to separate the wide section tunnel into return airway,gas special drainage gateway and non-pillar mining among the roadways;the seperation wall also acts as the roadside support to reserves gas gateway during stoping.After that,the gas special drainage gateway will be enlarged as the transportation lane in next section,which carries out mining without coal pillar between sections.