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

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.

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

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.

Doped Emulsion is a bulk explosive consisting of a blend of Emulsion with up to 50% AN prill added.

The addition of prill increases the heave componenet of the blend.

A blast hole containing two priming units, usually placed one near the top and one near the bottom of the blast hole.

Where, on a vertical drill pattern, a half spaced angled row is drilled to provide energy into the toe area of the front row.

A length of detonating cord or signal tube by which a Primer is lowered into a blast hole and which is the means of conducting the initiating signal down the blast hole.

A hole prepared for the insertion of an explosive charge.

A plan showing the layout of holes to be drilled for blasting.