Research on the Air Leakage Mechanisms and Prevention and Control Technologies for Goaf Groups in Shallow-Buried and Ultra-Close Coal Seams

The leakage network in shallow, closely spaced coal seam goaf areas is highly complex, and the "breathing" effect caused by external pressure disturbances poses a significant challenge for fire prevention. Taking the 83103 working face of Tangshangou Mine as a case study, this research employed surface fracture observation, energy potential measurement, and tracer gas techniques to investigate leakage mechanisms between the surface and the goaf group. The study analyzed the influence of surface climatic conditions, temperature, and atmospheric pressure on the disturbance patterns of abnormal gas leakage from the overlying goaf. Results show that surface fractures do not directly connect with the 83103 goaf; the main leakage source is the sealed wall of the 83101 track gateway. A three-dimensional leakage network characterized by "horizontal convection–vertical leakage" was identified between the 83103 goaf and adjacent overlying zones. Driven by pressure differentials, this "breathing" phenomenon correlates positively with surface temperature and negatively with atmospheric pressure. Sustained positive pressure differentials lead to substantial release of harmful gases from the overlying goaf. A coordinated leakage control system—including pressure equalization, fracture sealing, grouting reinforcement, and gas drainage—was proposed and implemented. Following these measures, CO concentration at the return corner decreased by 48.6% and O? concentration returned to normal, effectively suppressing gas exchange and reducing the risk of spontaneous combustion in the goaf group. This study provides a theoretical basis for leakage and fire control in similar abandoned mining areas.