Risk analysis and control technology of coal spontaneous combustion in the working face of protected soft thick coal seam

Abstract

With the gradual increase of coal seam mining depth, the protective seam mining has become a key scheme to effectively reduce coal spontaneous combustion. Aiming at the comprehensive prevention and control of coal spontaneous combustion in the goaf of protected coal seam mining face, the distribution range of coal spontaneous combustion risk area in the goaf of protected coal seam was determined by analyzing the risk disturbance factors such as expansion deformation of protected coal seam, fracture development, thermal storage environment of goaf and interlayer three-dimensional air leakage. The coal body of the working face was collected on site, and the characteristic parameters of coal spontaneous combustion were obtained through the test of gas production and heat release of coal spontaneous combustion. The dual prevention and control mechanism was formulated for multi-directional monitoring, classification and early warning and three-dimensional comprehensive management of spontaneous combustion; the coal spontaneous combustion prevention and control measures by air leakage sealing of large-scale grouting sealing and gel filling sealing from “whole” to “local”, “dynamic and static combination” of preventive nitrogen injection in dangerous areas of goaf and joint pressure equalization and fire extinguishing in working face were adopted. Numerical simulation analysis and field monitoring results showed that the coal spontaneous combustion in goaf of protected coal seam was effectively inhibited.

Keywords

• protected coal seam
• coal spontaneous combustion risk
• multi-directional monitoring
• leakage sealing
• integrated control