Abstract: As a very important roadway in metal mines,the safety and stability of production orepass have a significant impact on the stable production of mines. In view of the problems of damage,wear,plugging and blowout in the orepass,the PFC numerical simulation method is used to systematically study the ore unloading and drawing process of Y-type orepass under different material level heights by taking the ore fluidity and bottom hole load fluctuation as the evaluation indexes. The results show that the impact force of the ore on the shaft wall for the first time during unloading is the largest,and the damage to the shaft wall is significant. The material level height is closely related to the ore fluidity and the fluctuation of the bottom load of the orepass. When the material level height is too small,the ore in the storage section and the bottom is dense and the fluidity is poor. When the height of the material level is too large,the ore is in an unstable dynamic load state,and the impact of the bottom hole support structure fluctuates greatly,and the orepass is prone to damage. Under the reasonable material level height, the ore rock granular has good fluidity and the bottom hole stress state is relatively stable. The research results are of great significance to the analysis of the failure mechanism of orepass,and provide a research basis for reducing the risk of orepass plugging,blowout and failure. 

Key words: production orepass,PFC,material level height,load fluctuation,liquidity