中国矿山工程

In order to solve the problem of large area roof hanging in goaf when mining hard roof coal seam, the deep hole blasting method is proposed to weaken the roof, so the hard roof can collapse in time after mining. The research shows that if no weakening measures are taken in 12108 fully mechanized face, it is estimated that the first pressure step is 59.5m, a large area of roof hanging in the goaf will bring a significant threat to the safety of working face. After field application, the first pressure step of working face is 26.2m, the dynamic load coefficient is 1.35, the pressure step is short, and the weighting strength is significantly reduced, which creates a good condition for the initial mining of working face