Abstract: In order to reduce the impact of mining blasting vibration on Dongchuan River tunnel，140 mm small diameter blasting test was carried out on 1 200 m plate of southern Jinduicheng molybdenum surface mine.The detected blasting vibration data and rock fragmentation were analyzed in accordingly.The results showed that the blasting vibration velocity of small diameter blasting was significantly reduced compared with conventional production blasting of the mine，and the damping rate arranged from 60% to 75%.The small diameter blasting has advantages of low bulk rate，small average fragmentation and good rock fragmentation.At the same time，the safe distance of small diameter blasting was obtained.The finite element model of bench blasting was established with ANSYS，and the numerical simulation results confirmed the credibility of safety distance and damping rates from small diameter blasting experiments.

Key words: Small diameter blasting, Safe distance, Damping rate, Rock fragmentation, Numerical simulation