Study of Overlying Rock Structure and Intensive Pressure Control Technology of Island Longwall Panel in Extra-Thick Coal Seams

Abstract

In response to the severe occurrence of mining pressure in the fully mechanized top coal caving face of the extra-thick coal seam and the problem of strong rock pressure caused by the remaining coal pillars in the mining area on the isolated island fully mechanized top coal caving face, taking the 8102 isolated island working face of Tongxin Coal Mine as the background and by using methods such as on-site measurement and numerical simulation experiments, the characteristics of roof mining in the island longwall panel of extra-thick coal seams were analyzed. Establishing a mechanical model for the mining stress and overlying rock stress arch of an isolated working face, the mechanical characteristics of the isolated working face under special conditions were obtained. The results show that the longwall panel no. 8102 has an asymmetric long-arm T-shaped covering layer structure before mining and a C-shaped covering rock structure during mining, which will exacerbate the degree of mining pressure manifestation in the working face. Directional high-pressure hydraulic fracturing was implemented in the gob of longwall panel no. 8102, and the pressure reduction effect of the advance support section of the gob was obvious, ensuring the safety of the working face.