Abstract: Nine blast-rejection holes were found in Xinwutian Open-pit Mine in short term. In order to solve this problem，after excluding the general factors such as blasting equipment quality，blasting equipment performance，network design and man-made operation，starting from the combination of initiat⁃ ing explosive devices and blasthole environment，the seasonal climate environment of the region，the hy⁃ drological environment of the rock strata，the blasting effect of the combination of initiating explosive devic⁃ es of various manufacturers，the underwater contact environment of different devices，and the change of the specifications of the detonator are analyzed，and the possible causes are tested and verified. The analy⁃ sis shows that the distance between the energy-gathering cavity of the digital electronic detonator and the detonating core at the bottom of the functional hole of the detonating device is too large，and the detonator initiation can accelerate the attenuation due to the influence of the water medium interval of the water-bear⁃ ing blast hole，resulting in the blast rejection. According to the analysis results，a solution for lengthening the digital electronic detonator tube is developed，which successfully overcomes the occurrence of blast re⁃ jection.

Key words: water hole blasting, blast-rejection, initiation energy, interface standard, equipment combination