1.School of Safety Supervision，North China Institute of Science and Technology，Langfang，China； 2.Mine Safety Branch,China Coal Research Institute,Beijing ,China; 3. National Key Lab of Coal Resources High Efficient Mining and Clean Utilization,Beijing ,China

In order to ensure the safe and efficient mining of open-pit end coal under the influence of room pillar gob, the spatial relationship between the room and pillar gob and the slope was verified through TEM (Transient Electromagnetic Detection Technology), and the self-developed anchored multi-point displacement meter pair was used. The roof rock mass in the room-pillar gob during the end coal mining process was monitored three dimensionally, the rock mass stability under the coupling effect of the unloading stress of the slope and the vertical stress of the roof rock mass was was numerically simulated and the mining scheme was optimized. The results show that there were compound gob beams in the southern end of Ciyaota Mine, whose stability was mainly affected by the No.3-1 coal seam. The distance between the gob and the No.2-2 coal seam working side was 30 m in the buried depth, 50 m in the lateral distance embedded in the open pit. In the transverse direction, each monitoring point presents a displacement trend of “stable-growth-restable”, and the displacement change of the remote monitoring point was relatively stable; the opening of the longitudinal upper side coal mining had a great influence on the rock mass within 15 m of the shallow roof of the gob, and the shallow roof displacement shows a sharp increase in separation. The occurrence of the separation area was the precursor of the activation and movement of the roof of the gob; the mining of the end wall coal cause the slope to slide. The “corner chain concentrated effect” of the coal pillar appears in the slope from inside and outside, the upper rock mass of the gob has obvious unloading stress area, and the buried depth is 15 m, and the mining plan adjusted to reserve section 2 and reducing the bench height from 15 m to 12 m.