Print6.2.5: Key Properties Affecting Choice of Explosives
There are many properties that define an explosive. Some are of most value to the engineers and scientists that formulate and test explosive products. Others are useful to mining engineers designing blast rounds. We’re going to focus on the latter, and such a list would include the following:
Properties of the explosive are key to the design of the blast round, and that will become clearer when we will talk about the design of blast rounds. However, properties of the rock are equally influential, and we’ll talk more about this in the future.
- Density: kg/m3.
- Weight strength: is a measure of the explosive energy, kcal/kg.
- Bulk strength: is the product of density and weight strength of the explosive; and is indicative of the explosive energy in the hole, kcal/m3.
- Critical diameter: the minimum diameter of the explosive column to sustain the detonation or deflagration. This will determine the size (diameter) of the hole that we drill.
- Critical density: the maximum density at which the explosion may not propagate. As holes become deeper, the concern is that the weight of the column will become so great that the density of the explosive near the bottom of the borehole will exceed the critical density.
- Sensitiveness: a measure of propagating ability. You will hear this term, but won’t use it in a calculation, although it may influence your decision to use boosters in the hole.
- Sensitivity: a measure of the energy required to initiate the explosive. For our purposes, we’re usually not interested in a quantitative measure of this property; but, rather, we need to know simply: is it or is it not cap-sensitive?
- Water resistance: a qualitative measure for our purposes.