Ultrahigh-intensity blasting 'a step change' in ore processing

Groundbreaking research on using ultrahigh-intensity blasting to improve mine productivity has been awarded the 2014 CEEC Medal by the Coalition for Eco-Efficient Comminution (CEEC).

The new method involves a novel design modelling dual blast layers within a single blast event; all initiated with state-of-the art electronic blasting systems. For the first time it is possible to employ powder factors that are up to five times higher than conventional blasting. Independent modelling has shown that such powder factors can potentially increase mill throughput by 20-40%. 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.

Open cut gold mining, in particular, stands to benefit from this method. The research concluded that this new method could substantially increase gold mine production and profitability while reducing overall energy consumption and associated emissions.

The research was conducted by Orica’s Dr Geoff Brent and his research team. 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.

“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,” 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 processing.

“To date it has not been possible to blast at these ultrahigh 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 ultrahigh energies be safely utilised but they can also deliver improved mine productivity and reduce environmental impacts in open pit mines.

“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.

“The potential environmental benefits are also enormous. The technique has the potential to cut CO₂ emissions associated with grinding by up to 30%,” Dr Brent said.