The concept of explosives malfunctioning in rock blasting
- Canada Centre for Mineral and Energy Technology, Val d`Or, Quebec (Canada)
The problem of cross-hole explosive malfunctioning in rock blasting (including sympathetic detonation, desensitization and cut-offs) is a function of delay and spacing in a blast which should be designed to avoid such occurrences. On a delay-spacing chart, the phenomenon of explosive malfunctioning is explained by dividing the chart into different regions, while the shape and size of each region could vary from one explosive to the other. Over seventy blasts have been carried out at the CANMET Experimental Mine to identify the malfunctioning characteristics of specific emulsion, water-gel and dynamite explosives. In each experiment, two parallel blastholes, 32 mm in diameter and 1.7 m deep, were drilled downwards in an underground drift. Full coupling was achieved by tamping the explosives in the wet holes. The receptor hole is initiated with a delay following the donor hole in order to observe the timing effect on the explosives being shocked. High frequency vibration monitoring was used to identify the detonation or failure of the receptor hole. The VOD measurement was used for donor holes but not for the receptor holes because of the cut-off at the collar as a result of donor hole cratering, which was further confirmed with high speed video recording. The spacing is varied to modify the shock pressure the receptor charges are subjected to. Results are presented for the three explosives tested.
- OSTI ID:
- 398321
- Report Number(s):
- CONF-9401127-; TRN: IM9649%%529
- Resource Relation:
- Conference: 10. annual symposium on explosives and blasting research, Austin, TX (United States), 30 Jan 1994 - 30 Jan 1996; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the tenth annual symposium on explosives and blasting research; PB: 313 p.
- Country of Publication:
- United States
- Language:
- English
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