After entering deep mining of Sanxin Gold and copper mine in Hubei Province,a fan-shaped medium-deep hole blasting is adopted to excavate the top and bottom pillars.Due to the changes of hole layout and physical and mechanical rock properties,the fan-shaped medium-deep hole blasting has many problems,such as high bulk rate and serious shrinkage.To simulate the process of medium-deep hole blasting with different hole network parameters,the ANSYS/LS-DYNA numerical simulation software is used.Based on the actual physical and mechanical properties of on-site rock and the actual explosive material parameters,the numerical calculation models of three different hole bottom distances(1.4 m,1.6 m and 1.8 m) and three different row distances(1.6 m,1.8 m and 2.1 m) were established.By analyzing the effective stress cloud at the critical moment during the hole blasting process,the rock low-stress area of fan-shaped medium-deep hole blasting is concentrated on the upper and middle positions of the center lines of the two holes.By comparing the Von Mises effective stress peak on the monitoring unit at the key model position with the maximum dynamic tensile strength of rock material,it is determined that the effective stress peak is most close to the maximum dynamic tensile strength when the hole bottom distance is 2.1 m and the row spacing is 1.4 m.Therefore,these parameters are the optimal hole network parameters of fan-shaped medium-deep hole blasting of Sanxin Gold and copper mine.The field application test proves that a better hole bottom spacing and row spacing design can effectively reduce the problems of high bulk rate and serious hole shrinkage in fan-shaped medium-deep hole blasting under the same single explosive consumption.The research results can provide a guidance for subsequent mining work,and it has certain reference value for underground metal mine mining with similar problems.