Abstract: In order to solve the problems of high block rate and large blasting vibration in deep hole blasting in open-pit mines，the application research is carried out by using the characteristics of high delay precision and free setting of delay time of digital electronic detonator. Through the theoretical analysis of explosive explosion，the theoretical delay time between holes and rows in blasting network is calculated. The stress and vibration velocity around the blasting hole were analyzed and verified by numerical simulation. Combined with a large number of field blasting test data，the influence of digital electronic detonator blasting delay time on blasting fragmentation and blasting vibration was summarized. The results show that the blasting block rate can be effectively reduced by improving the delay accuracy of digital electronic detonator，and the ore powder rate is increased from 28% to 44.5%. By accurately controlling the delay time between holes and rows，the blasting vibration can be effectively reduced.

Key words: medium-length hole blasting, digital electronic detonators, delay time, block rate, blast vibration