Study on overburden failure characteristics in deep thick loose seam and thick coal seam mining

In order to solve the related problems of roof collapse in deep thick loose seam, taking the actual geological conditions of 1302 working face of Zhaolou Coal Mine as the geological background. A mechanical calculation and analysis model for a deep thick loose seam is established. A mining dynamic simulation was carried out using the numerical simulation software FLAC3D. Fracture development height was observed using a multi-stage plugging and leak detection system. Sublevel solid compaction filling technology was used to fill the goaf. Research shows that the caving zone, fissure development zone, and bending subsidence zone are formed during thick loose seam mining. The caving zone area is larger when the ground stress on the roof is larger, and fracture zones are better developed because the density of the loose seam area is smaller. Numerical simulation results are slightly larger than the measured results, so the roof overburden activity can be effectively predicted using the numerical simulation. The problem of serious roof collapse and surface subsidence in goafs can be effectively controlled using sectional compact filling technology.