The use of soundless chemical demolition agents in large scale in situ rock breaking applications in the mining industry

Abstract

Soundless chemical demolition agents (SCDAs) are proving to be the future of large-scale rock breaking. Unlike explosives, SCDAs do not generate negative environmental effects. This allows the SCDAs to be used in areas closer to communities and sensitive infrastructure. SCDAs are currently used in small-scale rock breaking applications but have not been tested in large-scale applications. The study evaluated whether SCDAs can break large volumes of in-situ rock. This was done by conducting five trials using Nex-Pand powder in four different surface mining sites. Trial 1 was unable to break the rock due to large confinement between the holes and the use of a hole diameter that was 182% bigger than recommended. Trial 2 fractured the rock with a crack width that reached 110 mm after 72 hours. Trial 3 generated cracks at the biggest hole diameter of 102 mm. Trial 4 had the smallest crack width due to the use on a stronger rock than in other trials. Trial 5 generated cracks at a slower rate than other trials because of the use of Nex-Pand powder at a lower ambient temperature than designed. The trials proved that SCDAs can replace explosives in areas closer to sensitive structures.