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Coal Engineering ›› 2026, Vol. 58 ›› Issue (5): 110-116.doi: 10.11799/ce202605014

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Evolution law of spontaneous combustion hazard zones in a composite goaf formed by adjacent opposing-extraction working faces #br#

  

  • Received:2025-09-08 Revised:2025-12-01 Online:2026-05-15 Published:2026-05-27

Abstract:

During the opposite-direction mining process of adjacent working faces, air leakage from neighboring goaf areas complicates the identification of coal spontaneous combustion risk zones in composite goafs. This study employs a combined approach of numerical simulation and field measurements to investigate the evolution patterns of coal spontaneous combustion risk zones in composite goafs before and after the convergence of adjacent opposite-direction mining faces. The research analyzes the influence of coal pillar porosity and working face pressure differentials on the distribution of coal spontaneous combustion risk zones. The results indicate that prior to face convergence, the maximum oxidation heating zone widths in the goafs of faces 2201 and 2206 were 39m and 37m, respectively. Following face convergence and intersection, with increasing coal pillar porosity, the oxidation heating zone width in the central and return air side of the 2206 goaf increased by 66m, while the spontaneous combustion risk zones on the intake air side of both 2201 and 2206 goafs decreased. Under increasing negative pressure differentials, the oxidation heating zone width in the 2201 goaf showed a slight increase, while the maximum width of the oxidation heating zone in the return air side and central area of the 2206 goaf reached 97m, with the risk zone area increasing by 48% for each doubling of negative pressure differential. With increasing positive pressure differentials, the oxidation zone width on the intake air side and central area of the 2201 goaf expanded, while both the cooling and oxidation zones in the 2206 goaf showed expansion trends. For each doubling of positive pressure differential, the oxidation heating zone width on the intake air side of the 2201 goaf increased by 69%, and the coal spontaneous combustion risk zone area in the 2206 goaf more than doubled. These findings provide valuable references for determining coal spontaneous combustion risk zones and formulating fire prevention strategies in similar goaf conditions.

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