Application of Shortwall Box Type Coal Mining Method to Strip Coal Pillar Mining

In order to solve the low coal resources mining rate of the strip mining and the too high cost problem of the backfill mining,with the theoretical analysis a nd the site measurement,a shortwall box type mining method was provided to recover the strip coal pillar. Based on the analysis on the stressed compression deformati on mechanism of the box type concrete wall + loaded strata loading mass,a secondary strata moving mechanics model was established and the safety coefficient of sta bility of the concrete under the condition was derived. According to the seam geological conditions,the clearance and width and compressive strength of the concrete w all were determined. The application of the technology to Huayuan Mine showed that on the premise of the ensured surface ground deformation controlled within the sc ope of I grade ,additional 0. 18 million tons of coal could be mined with good social and economic benefits.