Abstract: In order to solve the problem of long waiting time for truck loading caused by the unreasonable coordinated optimization of truck and shovel， the closed network model of mine is constructed by using queuing theory， and the production process is divided into multi-level service processes such as mining loading， heavy truck operation， weighing， unloading and empty truck operation. For the case of multiple shovels and normal distribution of loading time， the extended summary algorithm (ESUM) is introduced to solve the queuing index of all levels of service system in the closed network model. Based on the difference between the waiting queuing model and the mixed queuing model， the defect of large error in the early stage of ESUM is improved， and the accuracy of the improved results is higher. Taking an open pit mine as an example， according to the statistical analysis of the actual loading time of the mine， it is determined that the loading time of the mine obeys the rule of normal distribution. Secondly， the "single lane" queuing system is added to the closed network model according to the fact that only single lane is allowed to pass in a certain transportation section of the mine. By solving the model， the operation state of each production link of the mine is calculated under different truck numbers， and the mining and loading process is the key link to restrict the truck operation efficiency. Then， taking the minimum waiting time of trucks in the process of mining and loading as the goal and meeting the constraints of average shift production， the reasonable number of trucks in the open pit mine is determined to be 7. At this time ， the staying time of trucks in the process of mining and loading is 42.24% shorter than the original. Based on the above discussion results， the average queue length of mining and loading is simulated by MATLAB software platform， and the validity and accuracy of the synergetic optimization of open pit truck shovel by adopting ESUM is verified.

Key words: Open pit mine, Synergetic optimization of truck and shovel, Closed queueing network, Analogue simulation