Like many iron ore operations, this Pilbara-based mine was facing turbulent market conditions, with improving cost efficiency a key priority. The challenge, however, was not simply to reduce explosives consumption. Blasting performance at the site was already strong, with digging rates meeting planning expectations, there was no appetite for changes that could disrupt the balance of the mining value chain. As a result, any improvement needed to reduce drill and blast costs while maintaining digging performance, avoiding oversize, and keeping blasts compliant with operational requirements—a delicate balance. In practical terms, the site needed a low-disruption solution. A solution that could lower powder factor, reduce explosives-related CO2 emissions, and still deliver consistent downstream performance.

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After reviewing several drill and blast cost levers, the site selected airdecking as the preferred option, offering a pathway to improve stemming efficiency and reduce charge per hole. Compared with alternatives such as adjusting drill patterns, changing hole diameters, or switching explosive products, airdecking presented a practical solution with minimal disruption to established production systems. Trial blasts would need to be conducted to validate it.

To ensure the trials adequately represented site conditions, two geological domains—Channel iron deposit (CID) and Detrital iron deposit (DID)—were selected. These domains were chosen for their softer rock, lower blasting risk, and broad representation across the site’s complex.

To support implementation, MTi and the operator adopted a model-led approach to develop the new blast designs. Numerical modelling was used to assess how air decks influence energy distribution, stemming pressure, and breakage behaviour in the upper charge column. This work formed the basis for selecting practical designs capable of reducing explosive consumption while maintaining acceptable blasting outcomes.

From this point the team then progressed through a staged implementation program, beginning with a proof-of-concept phase, followed by extended trials and production rollout. This approach ensured the designs were validated under controlled conditions before being tested across a broad range of normal operating environments

Over five months, the extended trials covered 22 production blasts, 23,381 blastholes, and more than 11 million cubic metres of blasted rock, creating a robust dataset to assess both technical performance and operational feasibility.

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The results demonstrated that airdecking was an effective way to improve blast cost efficiency without compromising downstream productivity.

Across the 22 production blasts, the new designs achieved a 15.9% reduction in powder factor, delivering 1,039 tonnes of explosive savings and 1,053 tonnes of stemming savings. This corresponded to an estimated 12% reduction in blasting cost and 196.4 tonnes less explosives-related CO2-e emissions.

Just as importantly, these savings were achieved while maintaining blast compliance and digging performance. No out-of-specification fragmentation was recorded across the trial period, no flyrock or excessive ejection issues were reported, and average digging rates remained approximately 5% above planning targets.

At fleet level, all equipment performed at or above target on average, confirming that the reduced-charge designs preserved loading productivity at production scale.

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