Abstract: The mining activity of Jiguanzui Gold Mine is entered into deep mining stage,with the gradual introduction of production of the deep sections of the mine,the roadway relationships is more complicated,the problems such as long ventilation line and large ventilation resistance are becoming more and more serious.In order to solve the problems such as air volume insufficient,reverse airflow and air leakage in the middle production section,the ventilation system of the mine is optimized.Though the comparative analysis of four ventilation schemes,the one based on early underground concentration and late multi—stage machine relay is selected as the optimal scheme.In early stage,the main fan is used for centralized ventilation to meet the requirements of early stage ventilation,the investment of early stage engineering and fan equipment is reduced,there is no need to expropriate land,it facilitates ventilation management,in the late stage,the main fan in the early stage can be used as II level machine station relay.Besides that,three—dimensional ventilation calculation of the improvement scheme is done,the effective wind rate can reach 73.66％,and the wind speed qualification rate is greater than 75％,which is higher than the standard value.After the optimization of the ventilation system,the intended effects are obtained,the needs of safe production and operation environment in mines is met.

Key words: Deep mining, Ventilation system, Main fan, Multistage fan