A close to six-month trial at Evolution Mining’s Cracow underground gold mine in Queensland, Australia, has shown Minnovare’s Production Optimiser technology can have a significant positive impact on ore dilution.
In a newly released whitepaper, co-authored by Evolution Mining, the company compared the use of Minnovare’s new technology with the existing rig setup processes and technology Cracow normally uses (either an onboard digital inclinometer or handheld device).
With drilling conducted on 28 stopes (17 with the new technology and 11 with the existing process) for around six months from July to December 2017, the trial showed the Production Optimiser technology recorded 62% less average dilution than stopes drilled using the existing process. This equated to 11.7% overall dilution, compared with 28.9%, respectively.
The new technology, which was trialled using floating-boom mounted Epiroc 1257 and S7 long-hole rigs and a series of rings/holes drilled as part of the mine’s normal production stoping cycle, was proven to limit rig alignment error, reducing average blasthole deviation and increasing the number of holes drilled within tolerance by 160%, according to the report authors.
They extrapolated this data further and concluded that, if an equivalent reduction in dilution were applied to Cracow’s full year 2017 production data to the end of June – when 440,781 t was hauled and 89,496 oz of gold was produced – all things remaining equal, an additional A$8.2 million ($5.9 million) of ore would be recovered, with a A$4.5 million reduction in costs associated with haulage and processing.
As a result, the return per tonne would increase 22%, from A$87/t to A$106/t.
The results were so impressive Evolution is already considering a further rollout of the technology across Cracow.
Evolution Mining’s Phil Jones: “Aside from improving average stope performance, the Production Optimiser has provided us with greater reliability moving forward. With less overall dilution we’re also seeing less variation in dilution across stopes. We now have the confidence to set more ambitious targets, by considering new mine plans and blast patterns that would previously not have been considered.”
Budget dilution going forward at Cracow has already been lowered to approximately 10% in the 2019 financial year to the end of June based on recent successes. This will allow for higher-grade mill throughput and a reduction in mucking, hauling and milling unit costs, the authors said.
Minnovare’s Production Optimiser technology can be implemented on sites running any rig make/model and works independently of the rig’s on-board systems, according to the company.
The system’s hardware engages with Minnovare’s new online client interface, Minnovare CORE, which uses digital drill plans and plods that sync with existing mine-planning software to deliver drill-data capture and analysis capability. The net result, the company says, is a significant improvement in drill and blast efficiency, productivity and responsiveness – throughout the entire operation.
Since release, Minnovare has already signed up Northern Star Resources as a user.