Theoretical analysis and numerical simulation on protective seam extraction in Mayixi mine

Abstract

Gas accidents in coal mine have been considered as one of the worst coal mine disasters and often cause lots of death of miners. The protective extraction method is the most effective and regional way to prevent coal and gas outburst when multiple coal seams are mined in the outburst mine. In this paper, based on the theoretical analysis and feasibility study of applying the protective extraction technique to prevent outburst during multiple coal seams mining, the protective coal seam was determined by analyzing gas occurrence characteristics of each seam and the lithology of coal formation. Meanwhile, by considering the key influence factors for the selection of protective coal seam and the practical situations in Mayixi Coal Mine, the deformation rules of coal and rock mass during the mining process of protective seam were obtained by the numerical simulation of FLAC3D. The theoretical analysis and numerical simulation results show that choosing No. 5-2 Coal Seam as the protective seam to be mined first, can greatly eliminate outburst danger for the upper and lower protected seams, and achieve the goal of outburst prevention and gas control in region.