Moscow State Mining University, Moscow, Russia:

Kutuzov B. N., Professor, Doctor of Engineering Sciences, phone: +7 (499) 230-25-51

«Polyus» JSC, Krasnoyarsk, Russia:

Timofeev I. N., Deputy Chief Engineer of Drilling and Blasting Operations

«Polyus Gold» JSC, Krasnoyarsk, Russia:

Tokarenko A. V., Executive Officer of Olimpiadinsky Ore Dressing and Processing Enterprise

The recommendation of safety regulations of blasting operations to place two detonating primers in more than 15 meters hole depth with the obligatory duplication of borehole firing circut is now outdated. This happened due to the production of new and more secure string conductors: the detonating extrusion cords with the polyethylene cover and non-electrical initiation systems, in which the shock-wave pipes are used, instead of the detonating cords.

The held analysis have shown that the reach of high-speed detonation of emulsion explosives is slightely increased, with the increasing of mass of the explosive primers. However, in most cases, the whole charge is not detonated with the constant speed.

That`s why it is reasonable to place two detonating primers on some distance from one another at the bottom of the charge, or in its middle, so as both primers could detonate at the same time and involve the part of emulsion explosives, placed between the primers, into the process of high-speed detonation. It`s obvious, that this distance should be chosen on the basis of the experimental blasts, according to the type of emulsion explosives and the mass of the detonating primers.

The experiment was held in the «Vostochnyy» open pit of Olimpiadinsky ore dressing and processing enterprise («Polyus Gold» JSC). There were held 6 experimental blasts in total. The hole pattern can be moved apart to 1 meter with the corresponding decreasing of maximum consumption of explosives, during the initiation of charges by two paired detonating primers with 2-3 meters distance between them with their synchronous blasting. At the same time, there is reached the required reduction ratio of rock mass, with the reduction in value of drilling and blasting operations. This initation scheme is recommended for the commercial application.