Quality assessment of blasting caps with pyrotechnic delay in non-electric blasting systems in terms of their firing time
Blasting operations in surface and underground mining are characterized by the need to protect the environment from harmful effects of the detonation products of explosives, the fly rock zone, the seismic manifestations of the blast, as well as airborne shock waves. Non-electric blasting systems by various manufacturers are used in Russia, but all of them have certain advantages and disadvantages. It can be stated that the blasting caps of the applied blasting system do not always correctly execute the firing times specified by their manufacturer. Mismatches of the actual firing times from the rated ones might be so great that the applied blasting systems sometimes produce disturbances in the order of charge firing, which, in turn, may cause detonation failure in the boreholes. Studies have shown that in order to reduce the risk of detonation failures, regardless of their causes, it is recommended to initiate the borehole at two points with placing the second primer in the upper part of the borehole, or using extended priming charges.