When a shock tube lead fails under tension and the free end slaps against a hard surface. There is a known, but uncommon, failure mode that can lead to premature initiation. Where the lead that fires is a downline to a loaded hole the results can be catastrophic.

A 'Socket' is the remnant part of a blasthole remaining after firing.

Also referred to as a butt or bootleg.

The definition of a socket (South African regulation) is:

Any shot hole or any part of any shot hole, known not to be a misfired hole, which remains after being charged with explosives and blasted

A solution consisting of ammonium nitrate dissolved in water. For the manufacture of explosives the solution is ‘super saturated’. This means that the solution is made hot and allowed to cool without crystals forming.

The distance between blast holes and a row.

The difference between the spacing dimension and the burden dimension expressed as a ratio.

Breaking into fragments or small pieces.

The speed of sound varies with the medium it is travelling through as follows:

Air - 340 meters per second

Water - 1450 meters per second

Soft Rock - 3000 meters per second

Hard Rock - 5000 meters per second

Note that the speed of sound in rock is the 'seismic velocity' which is the speed that ground vibration travels.

A type of combustion which occurs without an external ignition source.

Multiple row blasthole pattern where each row is aligned directly behind the row in front.

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)