The effect of timing precision on control of blasting effects

Timing scatter limits what blasting results can be achieved and has a major effect on reproducibility. Dynamic blast phenomena occur in different timing windows, and the variability of the timing within any window needs to be within 30% of the desired interval. The quantum leap in accuracy offered by digital timing for detonators opens windows which were not accessible before, but the precision of electronic detonators varies considerably, and this can affect their performance in the field. There is a tendency to assume that “digital timing” means “no scatter”, and little awareness that long absolute digital delays can result in significant scatter for short intervals. In general, absolute scatter increases with delay time; for very long blasts there can be significant loss of control for the end holes. With restricted “time out” not only the maximum delay but also the inter-shot delays are limited.