Abstract:

To address the spontaneous combustion problem of residual coal in shallow-buried and close-distance coal seam group goaf, the 83101 working face of the No.13 coal seam and the 8201 goaf of the overlying No.12 coal seam in Tangshangou Coal Mine were taken as the engineering background. A multi-stage collaborative governance technology system encompassing ″before unsealing, after unsealing, and adjacent face prevention″ was constructed. Comprehensive technical means, including on-site monitoring point deployment, SF₆ tracer gas leakage diagnosis, infrared thermography combined with optical fiber temperature measurement, numerical simulation of pressure energy and air temperature coupling, three-dimensional grouting using Prute series materials, and pressure-balancing ventilation control, were employed to achieve precise identification and dynamic regulation of spontaneous combustion risk zones. The results indicate that the ″breathing″-induced gas leakage mechanism is driven by daily temperature variations in shallow-buried coal seams and the interconnected oxygen supply channels in close-distance coal seam groups. A collaborative governance technology chain centered on ″nitrogen injection for inertization, grouting for oxygen isolation, pressure balancing to suppress leakage, and water infusion for suffocation″ was developed. Following the unsealing of the 83101 working face, the average CO concentration decreases from a peak of 600×10^-6% to ≤24×10^-6%, with the maximum temperature drop at high temperature points reaching 500 ℃. Safe mining and equipment withdrawal were achieved at a slow advance rate of ≤2 m/d. Prior to mining the adjacent 83102 working face, the background CO concentration stabilizes at 0, validating the regional prevention effectiveness of the collaborative technology.

Key words: coal seam group, goaf, collaborative governance, spontaneous combustion of residual coal, ″breathing″-induced gas leakage