Wedge failures involve a failure mass defined by two discontinuities with a line of intersection that is inclined out of the slope face

The explosive strength of a unit mass of an explosive material expressed against a standard reference, e.g. ANFO. (See also bulk strength.)

A blast hole that contains any amount of detectable water.

Where water depth is recorded on a dip sheet this is the depth from the toe of the hole to top of the water.

Water depth is measured by listening and feeling for the top of the ware using a dip rope and weight. This length is subtracted to give the water depth.

For example if the top of the water is measured at 22m and the hole depth is 28m then the water depth is 6m.

Wet wall in a blast hole is a condition where there is water running on the blast hole walls above the toe or any other standing water.

This is generally related to the water table being above the toe or to perched water tables. The water does not accumulate resulting in standing water, there is a discharge path.

The main issue with wet walls is that they difficult to identify. The only way is for the blast crew to examine the dip rope after each hole and check if the tape is wet above any identified standing water. Consequently the dip rope must be dried (usually by dragging in dust) before each hole.

Where non-water-resistant explosives are loaded it is essential to identify wet walls to prevent product erosion and slumping.

Wet walls are measured from the toe of the hole to the highest wet area. Note that wet walls can not be less than standing water.

Example. The blast crew member records a 30m hole with 2m standing water but notices the tape is wet on the bottom 5m. This hole has 5m wet wall.

An explosion which occurs as a consequence of some other cause which would be obvious to an observer in the vicinity. (Two examples of obvious causes are large fires, or large amounts of fumes coming out of an ANE tank.)