Explosive evolution paper

© Tomas Sereda – za.fotolia.com

This is according to Simon Tose, group consulting mining engineer of AEL Mining Services (AEL), who recently published the paper "From fire setting to electronics - A fun look at the evolution of explosives".

Tose said that the main reason for the shift from the old dynamite cartridges to on-site chemical energy coupled with electronic blasting is that it offers more control over the blast and the environment, making the process significantly safer, more efficient and improving production.

"Looking back to the methods applied through the ages from fire setting , where one relied on heating the rock, throwing water on it to rapidly cool and then breaking it down, to dynamite and safety fuse there was no real control over the blast. These haphazard methods of blasting presented risks not only to the safety of miners, with no control over the air blast, ground vibration, noise or fragmentation of the rock, but was also very damaging to the environment," explained Tose.

More control over the environment

He said that electronic blasting is used both in surface and underground mining and provides far more control over the environment. "This control is allowed, because through these methods, one is able to manipulate the timing of the blast by blasting through one hole at a time, giving control over the air blast, ground vibration, noise and, most importantly, how the rock breaks (fragmentation)."

Tose said that mining is by its nature a very risky operation and, therefore, developing ways to make the process safer and more efficient has been the main driver in continuously developing explosives and improving the blasting processes.

"By taking chemicals to the mine and formulating explosives in the blast hole, we also eliminate some of the hassles of transporting hazardous explosives to the mine. With chemicals, transportation is very similar to the methods applied when transporting oil and gas. They are less volatile than the old dynamites, which were particularly hazardous during transportation.

"Chemicals are only mixed into the explosive formula when on the mining site; thereby eliminating the risk of a detonation during the transportation of these explosives."

Undue noise

Furthermore, he said that another important consideration is that with the electronic system and manipulation of timing one is able to blast without undue noise, one hole at a time, minimising rock vibration which could be detrimental and hazardous, especially when blasting in a city or suburban area.

Tose said that AEL is committed to making even greater strides in making blasting safer. "One of the big innovations we are working on is the complete elimination of lead in the environment. Nitrates have a negative effect on the ground and through the reduction of these elements we are able to reduce the impact of those chemicals on the ground."

He said that AEL is also looking at making the electronic system wireless in the future, which would eliminate the use of all wires and allow even more control in the environment where the blast is taking place.

"In order for South Africa to meet international safety standards, all stakeholders in the industry need to be aware of the progress that is currently being made and adopt new practices to improve their risk profile and reduce inefficiencies," concluded Tose.