Blasters should not underestimate the value of proper stemming
by anthony konya and dr. calvin j. konya
Stemming is a critical aspect of the blasting process that is often under-appreciated due to the misinformation that it is strictly for reducing the air overpressure (noise) from a blast. While this is important in sound-sensitive environments, such as close proximity to neighbors, little attention is paid to stemming in applications far from residential areas.
Anyone that has worked briefly around explosives could see that the stemming in Figure 1 is really poor. The burden is not breaking. Now let’s look at Figure 2. In this example, the rock is being broken, however, one can easily see the stemming material ejecting violently and on the left-hand side of the image one can see the stemming material being ejected before the breaking of the burden. The real question becomes: Is stemming a big enough a factor in blasting that one should spend energy and resources on it, and if so what exactly does it affect?