Abstract: A system for recording the use of individually identifiable detonators is described, the system comprising a data log of identified detonators; means to record electronically when a detonator is committed to fire; means to alter the data log to log as consumed a detonator recorded as so committed. A detonator is recorded as committed to fire only either when a detonator is intrinsically and irrevocably committed to fire or when an abort facility is set up in such manner that the system operates to remove the log entry of detonator consumption in the event that an abort signal is given. A method of recording the use of individually identifiable detonators is also described.

Abstract: A control system for controlling the initiation of detonation of a series of explosive charges (13) spaced apart from each other in boreholes (12) formed in a rock medium (10) to be blasted, said system being operative to apply controlled time difference in the time interval between successive detonations of at least one phase of the series of charges, and which includes at least three successive detonations, so as to reduce the probability of consecutive stimulation and amplification of ground vibration by reason of the detonation of the charges in the rock medium.