Mining3’s pursuit of a non-toxic post-blast bulk alternative explosive moved one step closer to its objective during the recent detonation performance tests conducted in December 2018. Using new materials in the formula, a series of detonation tests delivered improved explosive performance, reliability and product stability. These new materials supersede chemical gassing techniques to achieve improvements in the crucial characteristics of product stability and void space diameter.

Sensitisation of bulk hydrogel explosives is the process of introducing homogeneous void spaces into the blasting agent structure. During the microseconds of an explosion, the heat generated from the rapid collapse of the void spaces sustains the detonation reaction. Hence, the ability and performance of the hydrogel explosive is reliant on mechanical sensitisation and influenced by the diameter of the void spaces.

The two physical sensitisation materials tested, which are based on glass and polystyrene materials, confirmed detonation efficiency and will be utilised in 2019 field trials in both surface and underground applications. This latest development “will ensure the stability of the blasting formula specifically for on-site manufacture reducing the risk, cost and security associated with the transport and storage of explosives.”

In excess of seventy detonation tests were conducted over five days in high temperature field conditions at Rurex’s Byrock detonation range. The testing concludes phase one of the Physical Sensitiser Project.. The six-month investigation and collaboration with material suppliers worked to identify and manufacture the new sensitiser materials and ensure their efficiency.

“We have a renewed confidence in the robustness and performance of alternative explosives, superseding chemical gassing techniques”, states Dr Kettle. “We also had the opportunity to manufacture prototype cartridges for packaging the explosive, in preparation for underground mine-site trials proposed for 2019.”

The 1 m cartridges, maintain a barrier between the product and reactive rock surfaces whilst improving safety and loading of the explosive. Blast hole liners, another product packaging option, have recently been used in surface mining trials.