Borehole Delay

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Borehole Delay

 

the explosion at various times of separate parts of a space charge in a blasthole, with a time interval of thousandths of a second. The delay ensures the influence of the explosion of part of the charge on rock that is in a state of tension after the detonation of previous parts of the charge, increasing the portion of the explosion’s energy that is used for crushing. Multicharge short-delay explosions create the best conditions for interference of compression waves at all points of the part of the mass being broken out and thus ensures even crushing of the rock, which is particularly important for its subsequent removal and processing. Delay inside the borehole is achieved by the placement in the hole of several delay electric detonators or several threads of demolition cord with pyrotechnic relays for independent detonation of the part of the charge. These charges are used for explosive breaking-out of tough rock in the borehole in quarries.

REFERENCE

Drukovanyi, M. F., L. M. Geiman, and V. M. Komir. Novye melody i perspektivy razvitiia vzryvnykh rabot na kar’erakh. Moscow, 1966.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.