The square root of a number is a value that, when multiplied by itself, gives the number.

Example: 4 × 4 = 16, so the square root of 16 is 4.

The symbol is √

Another example: √36 = 6 (because 6 x 6 = 36)

ammonium nitrate, ammonium nitrate emulsions and ammonium nitrate mixtures containing greater than 45% ammonium nitrate, excluding solutions and ammonium nitrate products classified as class 1 explosives.

Multiple row blast hole pattern where each row is offset by half the spacing behind the row in front.

A measure of data spread in a normal distribution.

Written procedures containing an explicit description of how a job is to be performed. The SOP identifies the precautions required to safely and securely complete the task, and should include:-
• Personal protective equipment (PPE);
• Hazards specific to the job and/or site;
• The level of authority, responsibility and training required to complete the job safely;
• Reporting relationships identified by management and any other relationships that may interact with other jobs, SOP’s, or work instructions.
• Security Plans should be integrated into the set of SOP’s.

The initiation system component that gives the initial signal to start the blasting process.

A statement of attainment is issued by a Registered Training Organisation (RTO) when an individual has completed one or more units of competency from nationally recognised qualification/s or course/s. A Statement of Attainment will have the Nationally Recognised Training logo printed on it.

For shotfirers the Statement of Attainment must contain the required competencies. These are state specific but generally include

For Surface Operations

RIIBLA301D Conduct surface shotfiring operations

RIIBLA205D Store, handle and transport explosives

RIIBLA305D Conduct secondary blasting

RIIBLA402D Monitor and control the effects of blasting on the environment

For Underground Operations (not Coal)

RIIBLA303D Conduct underground development shotfiring

RIIBLA304D Conduct underground production shotfiring

RIIBLA205D Store, handle and transport explosives

RIIBLA305D Conduct secondary blasting

Extraneous electricity which consists of an electrical charge that is stored on some object or person and is usually generated by friction between materials.

Aggregate or other inert material used to maximize the effect of an explosion, by filling the remainder of holes or between decks of explosives after the holes have been charged with explosives.

The length of the stemming column should be between 20 to 30 blast hole diameters.

For average conditions choose 25 diameters.

For a 200mm diameter hole this would be 5m of stemming.

Where the stemming material is angular material with fines screened out and the bench is solid material at the collar the stemming column may be reduced to 20 diameters.

If the stemming column is reduced much below 20 diameters the likelihood of cratering and rifling increases.

If the stemming column is increase above 30 diameters there is the potential to leave blocky material at the collar.

Noise / airblast caused by the venting of high pressure blast gases through the blasthole collar, often accompanied by rifling of the stemming.