Blast Training International

Charges placed above a base charge at preselected intervals and which are completely separated from the base charge and each other.

Decomposition

The separation of a substance into simpler substances or basic elements. Decomposition can be brought about by exposure to heat, light, or chemical or biological activity.

The chemical decomposition of an explosive may take years, days, hours, or a fraction of a second. The slower processes of decomposition take place in storage and are of interest only from a stability standpoint. Of more interest are the two rapid forms of decomposition, deflagration and detonation.

A decoupled explosive is one that does not fill the blast hole. Decoupling is achieved by loading packages or tubes of explosives of a smaller diameter than the drill hole.

Decoupling is used to reduce the energy delivered by a blast hole. Both the reduced amount of explosives and the air-gap around the product are effective in reducing blast hole pressures.

Decoupled charges are commonly used when presplitting with drill holes up to 115mm in diameter.

Typical continuous packaged explosives loaded as a decoupled charge into a presplit.

Deflagration is a term describing subsonic combustion propagating through heat transfer; hot burning material heats the next layer of cold material and ignites it. Most "fire" found in daily life, from flames to explosions, is deflagration. Deflagration is different from detonation, which is supersonic and propagates through shock.

 Deflagration is a rapid high energy release combustion event that propagates through a gas or an explosive material at subsonic speeds, driven by the transfer of heat.

A detonator which contains a delay device designed to fire at a fixed interval after ignition.

A pyrotechnic substance contained within a metal jacket which causes a delay between the instant application of energy
and the time of detonation of the base charge of the detonator.

The lapse of time between the application of a firing signal and the detonation of the base charge of a delay detonator.

Combination of delay elements within a detonator.

Where hole B requires hole A to have fired to provide the necessary relief then hole B is dependent on Hole A.

A flexible cord with a solid core of high explosives, commonly PETN.