Research on surrounding rock control technology for gob-side entry in close-distance lower coal seam.

Research on the surrounding rock control technology of along-the-gob roadways in close-distance lower coal seams of the Xiaoyu Mine in Shuozhou City, Shanxi Province, is conducted using theoretical analysis, numerical simulation, field application, and effect monitoring. The results show that due to the residual coal pillars, the surrounding rock of the roadways is in a stress-concentration environment, especially with a significant increase in vertical stress on both sides and shoulders of the roadways, posing a serious risk of shear failure. Small coal pillars in the lower coal seam can effectively reduce the impact of residual coal pillars on the stability of the roadways. In the goaf and solid coal areas, the roadways are in a lower surrounding rock stress environment, and conventional roadway support schemes can be used. In the residual coal pillar area, the roadways are in a stress-concentration environment and require enhanced roadway support. Field monitoring results indicate that during roadheading and recovery, the deformation of both sides and the roof and floor of the along-the-gob roadways is always within a controllable range, and the surrounding rock stability is good.