The design concept was to drill out the wedge as a forward stripping blast and to pre-charge this with WebGen™ prior to firing the rise and slot widening shots. The blast was designed to cast the broken rock from the wedge back into the previously fired rise and widening void.
The first blast performed very well with 99% of design tonnes recovered and a favourable cavity scan (CMS). The design was incorporated into the rise and widening methodology and subsequent blasts continue to exhibit very good void and tonnage profiles. The ongoing success of the forward stripping also facilitates maximum ore extraction with minimal dilution particularly from the level below. Forward stripping combined with rise and slot widening blasting has demonstrated increased primary ore recovery from 75% of insitu design tonnes to 95%. This is equivalent to 75,000 tonnes per level. Additional benefits are discussed on the paper.
Author: M Hawtin, J Say, P Cann, and L Carlon
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