4. Application of Paste Materials in Mitigation of Subsidence Caused by Room-and-Pillar Mining

The surface deformations caused by shallow goafs can result in serious damage to buildings (structures) during mining. The movement duration is typically short, and the underground void rate and residual deformation are relatively small. The collapse pits formed on the surface of shallow unconventional room-and-pillar goaf can cause serious damage to ground buildings. The underground voids and residual deformation left in the goafs may also pose a potential hazard to surface stability. A paste filling technology is successfully used to remediate the shallow goafs. Paste filling materials have the characteristics of high solidity, high strength and good economic benefits. They have great advantages for goafs in coal mines where the roof rock strata are relatively complete and hard, the goaf space is relatively large, and the roof has not collapsed or has not completely collapsed.