Research and application of gob-side entry retaining technology with high water filling in fully mechanized mining face of Jining No.3 coal mine

In view of the problems of large coal pillar and waste of resources in 04 (south) -2 fully mechanized coal gangue filling face under 63 in Jisan Coal Mine, the technology of gob-side entry retaining with high water filling was studied. By analyzing the geological conditions and construction requirements of the working face, the key parameters of the high-water filling bag are determined: width 2.0 m, length 2.7 m and height 3.9 m, and five rows and four columns are used to reinforce the anchor bolts. Based on the mechanical model of simply supported beam, the strength of filling body is calculated to be 7.5 MPa, and the design strength is 10 MPa after considering the safety factor. The construction process of filling wall is optimized, and the roof support and reinforcement support scheme of filling area are designed. The field application shows that the effect of this technology is good, and the maximum moving distance of the roof and floor and the two sides at 180 m from the working face is 146 mm and 166 mm, respectively, which ensures the stability of the roadway and the safe mining of the working face.