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Improving mine productivity through ultra-high intensity blasting
12 Aug 2014
Orica’s Dr Geoff Brent and his research team have been recognised for groundbreaking research using a novel method of Ultra-High Intensity Blasting to improve mine productivity.
Ultra-High Intensity Blasting – A New Paradigm in Mining, authored by a team led by Dr Brent has been awarded the 2014 CEEC Medal by the Coalition for Eco-Efficient Comminution (CEEC).
Congratulating Dr Brent on this significant achievement, Orica Managing Director Ian Smith said the quest to use the chemical energy in explosives to improve ore fragmentation and deliver a step change in mine processing efficiency was a priority for the global resources sector.
“This research is a demonstration of Orica’s commitment to the development of resourceful solutions through innovation to improve mine productivity. The use of electricity to mill ore is usually the largest consumer of energy on a mine site and ore comminution constitutes a significant percentage of electricity consumed worldwide,” Mr Smith said.
“Independent modelling has indicated that increasing the explosive energy by several fold can lead to increases in mill circuit throughput of up to 40% and savings of tens of millions of dollars annually,” Mr Smith said.
Speaking on behalf of the research team, Dr Brent said: “By utilising explosive energy in the pit to produce much finer ore we can dramatically increase the efficiency and throughput of the downstream comminution processes of crushing and milling. The overall energy consumption across the mining and milling cycle can be reduced with a consequent reduction in emissions. This is a step-change in ore
‘To date it has not been possible to blast at these ultra-high explosive energies, or powder factors, due to safety and environmental constraints,” Dr Brent said.
“However, the new technique demonstrated for the first time that not only can these ultra-high energies be safely utilised but they can also deliver improved mine productivity and reduce environmental impacts in open pit mines. The key to the breakthrough has been to use the rock itself to contain the explosive energy by the selective deployment of state-of-the-art digital electronic initiation systems in novel blast designs. The new method was thoroughly tested in blast models and then verified in large scale production blasts.
“This breakthrough approach is particularly important given the worldwide trend of decreasing ore grades. More ore needs to be ground and processed in order to achieve production targets and this method has the potential to generate a step change in mine productivity, particularly in complex or lower grade ore bodies. It can render ore bodies that might ordinarily be uneconomic both affordable and practical to extract,” Dr Brent said.
“The potential environmental benefits are also enormous. The technique has the potential to cut CO2 emissions associated with grinding by up to 30%“.
In recognition of their research in the field Dr Brent and his research team will be presented with the 2014 CEEC Medal at the International Mining and Resources Conference to be held in Melbourne September.
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Editors Notes and citation:
Citation: Brent, G F, Dare-Bryan, PJ, Hawke, SM and Rothery, MD, 2013. Ultra-high-intensity blasting – a new paradigm in mining, in Proceedings World Gold 2013, pp 395-400 (The Australasian Institute of Mining and Metallurgy: Melbourne).
Abstract: Mine-to-mill studies have previously demonstrated downstream productivity benefits from relatively modest increases in blast energy, or powder factor. These increases have up to now been limited by safety and environmental constraints since excessive blast energy can result in flyrock, unacceptable vibration, airblast and wall damage.
Here, a new blasting method that overcomes these constraints is presented. For the first time it is possible to employ powder factors that are up to five times higher than conventional blasting. Independent modeling has shown that such powder factors can potentially increase mill throughput by 20 to 40 per cent. The economic implications are substantial, both in terms of increasing production in existing operations and in consideration of capital and plant requirements for greenfield sites. In addition, mill electricity and grinding media consumption and their associated costs and energy and emissions penalties can be reduced.
This method represents a step-change in blasting practices. It involves a novel design modeling dual blast layers within a single blast event; all initiated with state-of-the art electronic blasting systems. The energies in the lower layer can be as high as five times the standard energies, providing for intense fragmentation of the ore. Results from blast models have been confirmed in field trials of the method.
Open cut gold mining, in particular, stands to benefit from this method. As gold grades decline, milling costs and throughput increasingly become constraints on production that can be alleviated with this new method. Additionally, it opens possibilities for improved recovery. Blast modeling studies show that dilution of gold ore within the blast can be managed with the new method. Furthermore, it has been shown that vibration from the new method is actually lower than from conventional blasting, allowing the use of the technique in proximity to mine highwalls and other key infrastructure such as underground orepasses.
It is concluded that this new method could substantially increase gold mine production and profitability while reducing overall energy consumption and associated emissions.
1 Link to Abstract