Research on Rational Width of Entry Protection Coal-Pillar in Large Mining Height Work-Face of Shallow Coal Seam

For the study on the problem of rational width of entry protection coal-pillar, according to the gateway of 5103 mining face in Heshan Mine, through theoretical calculation and numerical simulation, rational width of entry protection coal-pillar was educed, which was 25 m. The roof and floor and 2-sides deformation were both 35 mm through engineering practice, and its feasibility was demonstrated, which provided some theoretical references for preserving reasonable coal-pillar for the similar coalface with large mining height.