Firing Delay Characteristics of Instantaneous and Seismic Detonators.
Bajpayee-TS; Mainiero-RJ; Hay-JE
This report describes an evaluation by the Bureau of Mines of the firing delay and interval of commercially available instantaneous and seismic detonators considered for use with nonincendive sheathed explosive rock-breaker charges. Detonators manufactured by three domestic companies were evaluated. Time measurements were based on the principle of detecting ionization at the detonation front. High- resolution digital oscilloscopes and twisted-pair ionization probes were integral parts of the experimental setup. Firing delays and firing intervals were measured using 3 different test procedures: (1) 3 detonators in series with a 100-ft long 16-gauge firing line fired by a 20-shot permissible blasting machine, (2) 2 detonators in series fired by a 20-shot blasting machine through a total circuit resistance of 25 ohms, and (3) 2 detonators in series fired by a 20- shot permissible blasting machine through a total circuit resistance of 150 ohms.
IH; Report of Investigations