Abstract: In order to solve the ventilation problems such as air leakage in the upper subsidence area of the south southwest wing of Ekou Iron Mine and the coordinated operation imbalance of multi-stage fans，the ventilation system is optimized to improve the effective air volume rate of the mine and ensure safe and effi‐ cient mining. The node wind pressure balance technology is used to optimize the critical path wind resis‐ tance，and the air volume distribution is adjusted in combination with the combined ventilation of the main and auxiliary multi-fans. A main-auxiliary combined ventilation method based on wind pressure balance is proposed to realize the coordinated operation of multiple fans in series and parallel. A three-dimensional ven‐ tilation model with air leakage path in subsidence area is established to dynamically match the air volume of each middle section. Through real-time wind speed monitoring and intelligent control，the air leakage node tends to zero wind pressure state，and the air leakage effect is suppressed. The field application shows that the effective air volume in the optimized mining area is increased from 75.25 m3 /s to 77.42 m3 /s，with an in‐ crease of 2.9%. The air leakage in the upper caving area decreased from 50.21 m3 /s to 4.24 m3 /s，with a de‐ crease of 93.4%，which significantly improved the effective air volume efficiency of mine ventilation. The technical system effectively solves the problem of air leakage in complex caving areas and optimizes the coor‐ dinated operation of multiple fans through pressure balance control, air flow collaborative distribution and fan dynamic adaptation, which provides an important reference for similar mine ventilation system optimization.

Key words: ventilation system optimization, air pressure balance, main and auxiliary fan coordina‐ tion, effective air volume rate