Optimisation of blasting practices in caving operations

Sublevel Caving (SLC) is heavily reliant on blasting practices to create optimal fragmentation and recovery of blasted ore, for overall mine productivity. The E26 SLC has experienced poor blasting outcomes on the initial two sublevels, which has instigated a high requirement for rework processes for continual extraction and retreat of the cave front. The poor blasting outcomes and subsequent rework processes in the SLC has limited production, impacted recovery with multiple rings fired in one blast, as well as, caused issues with fragmentation and the flow of rock in drawpoints. The SLC footprint is characterised by irregular sublevel designs due to the proximity of caved areas and pre-existing infrastructure. The variable layout has impacted on the ability to optimise drill and blast practices as once a design matures to a level of success in one layout, the success cannot be replicated in another layout. The aim of this research was to identify the failure modes experienced in the E26 SLC and the frequency of occurrence, to establish a base case. The primary objective was the recognition of an optimisation pathway, in line with the failure modes and to undertake full-scale experiments to ensure workability in the operating SLC. The target of the optimisation was to reduce rework processes, increase single ring firings, improve compliance to the cave draw strategy and decrease the exposure times of underground personnel to the drawpoint brow.