Overlying Strata Separation Grouting Mining Design for Working Face 23041 of Gaocheng Coal Mine

Abstract

To address the requirements of protecting cultural relics such as the Yangcheng Ruins and tackling the overlying rock reverse-inclination zone formed by the influence of sliding structures at the 23041 working face of Gaocheng Coal Mine, this study employed similar simulation tests (with a geometric similarity ratio of 1:1000). It was verified that after mining at this working face, the actual height of the caving zone reaches 53 meters and that of the fractured zone is 121 meters, and the optimal grouting horizon was determined to be 145 meters below the main key stratum. Based on these findings, an overlying rock separation grouting scheme and a layout of 5 grouting boreholes were designed. After implementation, the maximum surface subsidence was reduced from 3215 mm (Grade Ⅳ damage) under conventional mining to 598 mm (within Grade Ⅰ deformation). This research fills the gap in studies on mining laws in overlying rock reverse-inclination zones under the influence of sliding structures and provides support for cultural relic protection and the mining of coal resources under "three under" (under buildings, railways, and water bodies) conditions.