Leakage detection and prevention technology for goaf areas in pillarless coal mining at Xinji No. 1 Mine

To address the issues of leakage and spontaneous combustion in goaf areas of the Y-type ventilation working face pillarless extraction, as well as the adjacent old goaf areas, a combined method of energy potential measurement and tracer technology was used to detect air leakage in the sealing walls of the goaf areas of the 360606 working face at Xinji No. 1 Mine. The results showed that the energy potential of the intake system in the 3608 (06) mining area was higher than that of the return air system. There were leakage channels between the 360606 working face goaf, the overlying goaf, and adjacent goaf areas. The sealing wall of the −550 m West Wing Belt Stone Gate (North) was the main source of air leakage. The leakage sink occurred at the −415 m West Main Tunnel sealing wall, the −415 m Auxiliary Return Air Mountain sealing wall, the −415 m Mine Bottom Car Track Detour sealing wall, the 360608 Transport Tunnel sealing wall, the 360606 Return Air Corner, and the air inlet holes of the 360606 working face flexible model wall. Based on the characteristics of the 360606 working face and its leakage channels with adjacent goaf areas, measures such as nitrogen injection grouting for sealing and the installation of wind curtains were proposed. Application results indicate that after comprehensive prevention and control measures were implemented for the leakage in the 360606 working face goaf, the CO and O2 concentrations in the air in the retention roadway and return air side goaf areas remained within the normal range, effectively controlling the leakage and ensuring safe production in the 360606 working face.