Test blasting was carried out for the applicability of vibration reduction method by controlling
the initiation time in the quarry. The blasting design was taken like that the blast hole interval
is 2 m as 10 holes 4 stages, line of least resistance is 2 m, blast hole diameter is 65 mm. The
blasting initiation time of the experiments set difference time every 10 holes 1 stage. The
initiation delay time was calculated by the frequency analysis of the test blasting vibration.
Simultaneously, it also obtained a delay time as largest negative correlation according to
autocorrelation function of vibration waveform, and the setting method of optimum delay
initiation time was discussed.
The maximum of vibration level is about 22.5 Hz as the result of the frequency analysis of
test blasting. So the optimum time difference is 22.2 ms each initiation time. This value shows
a negative value even in the analysis according to the autocorrelation function. It was shown
that the blasting vibration could be reduced by the interference of the blasting vibration with
optimum time by the frequency analysis using precise initiation machine and electric detonator
on the field experiment in the quarry.