Relieved gas drainage and comprehensive control in gob of Y-type coal face in the first coal seam mining of deep multi-seams

In this paper, in view of the difficulties of relieved gas control in the first coal seam mining of the deep multiseams with high gas and low permeability, taking Coal Face 1111(1) in Zhuji Coal Mine as example, we provided and implemented the technique to strengthen the wall closeness of gob remained entry, and the gob relieved gas drainage technique in the gob remained entry of Y-type ventilation coal face, with the combination of gob gas delivery law in Y-type coal face and the advantage of accumulated relieved gas withtin the gob. In addition, combined with the gas drainage in the upper relieved coal seam by the surface well drilling, the safety and high efficiency mining in the first coal seamin of deep multiseams was realized. The results show that the maximal and average absolute gas emission quantity is 72.39 m3/min and 43.64 m3/min, respectively. When the air volume in the face is 2290~2700 m3/min, and the gas concentration in the return airflow is less than 0.6%, the average gas drainage volume is 34.27 m3/min, where the average gas drainage volume in buried pipes is about 21.94 m3/min, which is 64% of the total gas drainage volume. Moreover, the average gas drainage rate is about 78% during the mining process. The research achievement can provide the basis for gas drainage and control in the first coal seam mining of similar deep multiseams in the future.