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detonating cord union

A joiner to connect detonating cord.

Contains about 2 grams of HMX explosive

det cord union 1

Entry link: detonating cord union


A shockwave driven reaction at a velocity great than the speed of sound in the medium.


Entry link: Detonation


A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common.

 The commercial use of explosives uses non-electric or electric detonators. Many detonators' primary explosive is a material called Lead Azide pressed into place above the base charge, usually PETN.

 Delay detonators have a pyrotechnic delay train above the primary charge. This provides a time delay between the firing of the downline and the detonation of the base charge.

detonator construction 01

Entry link: Detonator

Detonator (or cap) Sensitive

A term applied to any explosive which can be reliably initiated in the unconfined state by a number 8 detonator.

Entry link: Detonator (or cap) Sensitive

Dewatered Hole

A blast hole which has had water removed using an in-hole pump or other mechanical means.

dewatering truck

Typical dewatering truck fitted with submersible pump.

Entry link: Dewatered Hole

Direct Supervision

Direct supervision is a term that is used to refer to situations in which a supervisor is present at all times. The supervisor oversees activities as they occur and provides constant direction, feedback, and assistance. For some types of workplaces, direct supervision is required for safety and health reasons.


A test for direct supervision is that the supervisor is constantly aware of what the supervised person is doing and is able to immediately communicate direction (such as Stop That Now!!)

Entry link: Direct Supervision

Direction of Movement

The preferred direction in which the blasted rock mass moves under influence of the blast – at right angles to the ‘angle of initiation’.

Entry link: Direction of Movement

Dislocation Failure

A form of misfire in which some explosive is left undetonated as a result of an adjacent explosion, eg. separation of charge by ground movement or severance of the initiating line.

Entry link: Dislocation Failure


One of the six divisions into which explosives are subdivided as follows:

Division 1.1 Explosives - Substances and articles which have a mass explosion hazard (a mass explosion is one which affects almost the entire load virtually instantaneously).

Division 1.2 Substances and articles which have a projection hazard but not a mass explosion hazard.

Division 1.3 Substances and articles which have a fire hazard and either a minor blast hazard or a minor projection hazard, or both, but not a mass explosion hazard.

Division 1.4 Substances and articles which present no significant hazard.

Division 1.5 Explosives - Very insensitive substances which have a mass explosion hazard. This division comprises substances which have a mass explosion hazard but are so insensitive that there is very little probability of initiation or transition from burning to detonation under normal conditions of transport.

Division 1.6 Articles containing extremely insensitive explosives.

NOTE: For a complete evaluation of these divisions see AS 1216.

Division 5.1 Oxidisers - Substances which, while not combustible, may by readily liberating oxygen, cause or contribute to the combustion of other material, and have been classified as Class 5.1 by the appropriate regulatory authority. These substances would be expected to fail the UN test for determining whether a material is a Class 1 explosive.

Hazard Division and Compatibility Group are the key descriptors used for storage and transport classification.

The following are typical for commercial explosives

11b 11d

Entry link: Division


In terms of explosives and blasting:

The 'donor' is the first part of the Donor-Receptor relationship that delivers energy to the receptor.

The key factor of the donor is the amount of energy provided. This may be measured in terms of equivalent mass of TNT.

The 'receptor' is the second part of the Donor-Receptor' relationship that accepts energy from the donor and, if sensitive enough, will then detonate.

On detonation the receptor becomes the donor to the next part of the explosives chain.

The Donor-Receptor relationship may be summarised as:

For reliable propagation the output of the donor must exceed the sensitivity of the receptor.

The Donor-Receptor relationship is key to understanding propagation and failures.

Entry link: Donor

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