Study on the mechanisms and prevention of water inrush events in a deeply buried high-pressure coal seam—a case study of the Chensilou Coal Mine in China

Abstract

Coal mine formations are becoming increasingly threatened by water inrush accidents resulting from high-pressure water conditions in limestone formations below mines with increasingly greater mining depths. This paper focuses on the floor of a deeply buried coal seam and the high-pressure fully mechanized mining faces of the Chensilou Coal Mine in China. Based on systematic observations and analysis of the geological and hydrogeological conditions in the study area, this study conducts theoretical analyses, numerical simulations, and underground observations in a comprehensive manner. Accordingly, a systematic and substantive investigation of the deformation and failure of the deep mining floor and the water inrush mechanism (i.e., the high hydraulic pressure within ash-filled fissures) in the Chensilou Coal Mine is carried out. The burial depth is deeper than 761.4 m, and the water pressure in the limestone of the Taiyuan Formation exceeds 4.95 MPa. Furthermore, the mining depth of the working face is 34.25 m. Based on data on water inrush events and subsurface mining failure depth, the water inrush mechanism in the floor of the coal seam in the Taiyuan Formation is analyzed. The end hole depth of the working face is composed of the L8 limestone, and transient electromagnetic detection technology is used to test the grouting effect of the working face floor and ensure the mining safety of the three working faces tested in this study.