Study on Support Technology of Gateway in Contiguous Seams Under Mining Goaf in Pingshuo Mining Area

In order to solve the support dfficult problem of a gateway in contiguous seams under the mining goaf in Pingshuo Mining Area, a seam geological mech anics test, surrounding rock structure observation, theoretical analysis on bolt support role and numerical simulation analysis method were applied. According to the diff erent distance between the seam gateway to the upper mining goaf, the paper provided the bolt + short anchor, full length pre-stressed bolt mainly with bolt support. Th e results showed that the bolt support could meet the requirements of the gateway support in the contiguous seams under the goaf. The integrated convergence of the gateway was small, the roof and floor convergence was 0. 69% of the gateway driving height and the two sidewall convergence of the gateway was 0. 60% of the gatew ay width. A shallow bed separation was 0. 4 mm and a deep bed separation was zero. The bolt pretension was 20 ~ 30 kN, the anchor pretension was 76 ~ 84 kN and t he bolt and anchor loading was stable. AII above technologies could ensure the stability of the gateway in the contiguous seams under the mining goaf.