MINING ENGINES
transmission with a brand-new transfer case and put that“ assembly” back in the truck. That transfer case includes an extended set of gears that allows Switch to hang two 540 kW motors off it. Between the tyres on one side of the vehicle is a 90-kWh, 1 MWcapable battery pack powered by Echion’ s XNO battery chemistry.
Earlier this year, the truck arrived on site in Western Australia, and it is now integrated into the operating fleet at the mine.
O’ Hanlon told IM:“ After proving out the truck’ s credentials in a‘ development shakedown area’ at PLS – one which included a 10 % grade ramp with 30 m vertical elevation – we recently progressed to operating in the open-pit mine.”
Switch has modelled a 17-20 % reduction in fuel burn for this installation, and has demonstrated increased speed on grade, which is a compelling proposition for any miner.
“ It’ s looking very promising, as we see this trial showcasing the major benefits of effective hybridisation: companies come for the fuel savings and stay for the productivity,” O’ Hanlon said.
And Ting, conscious that the XNO pack has been integrated into a brand-new vehicle, is confident such gains will not be short lived.
“ The longevity of this battery will be proven out over time, but simulations in similar applications have shown upwards of 30,000 cycles,” Ting said.“ That is way beyond the lifecycle of any other chemistry event attempting to operating at the power levels which XNO does.”
The battery on board the Cat 785 supports 10C charge and discharge rates and is integrated into a revised fuel tank / battery assembly that fits inside the mass and volume envelope of a long-range tank, according to the companies. It will also enable testing of the hybrid transmission at up to 1 MW in both drive and regenerative braking modes.
Outside of the PLS installation, Ting is concentrating on commercialising the existing generation XNO pack platform – a feat that will inevitably lower unit costs – as well as pursuing a joint pathway for a solution that supports 30C charge and discharge rates.
He explained:“ Already, the pack is the highest power density pack for heavyduty vehicles, when considering charge power that is vital for hybrids. However, we have 20C- and 30C-capable cells, and the engineering to get the most out of these at pack level is being undertaken already.
“ We see this as the right direction, as the early data we have received on the hybrid trucks, as well as our analysis of haulage routes show that we would still have excess energy on board, even at 10C, which is wasted.
“ It makes sense in these cases to invest in increasing power capability as opposed to energy storage. That is the message I would give the mining companies looking at hybridisation: size a battery for power, not for energy.”
A new hybrid haulage entrant
Rolls-Royce Power Systems is also developing a hybrid drive system for haul trucks, with a prototype built and the company making the final preparations for commissioning at a mine site.
The system combines proven mtu Series 4000 engines with a high-performance electric drivetrain. Depending on the topography and operational profile of the mine, this can result in savings of up to 30 % in fuel consumption and CO₂ emissions compared with conventional drive systems, the company said.
The hybrid system stores the haul truck’ s braking energy in batteries during downhill journeys. This energy is then used to drive the wheel motors during the subsequent uphill journey. As a result, the diesel engine operates under a lower load and consumes significantly less fuel. At the same time, CO₂ emissions are reduced.
The aim is a modular, scalable system that can be adapted to different vehicle types, mine topographies and operating conditions, the company explained.
Cobus van Schalkwyk, Vice President Global Mining at Rolls-Royce Power Systems, said:“ Transport in open-pit mining using haul trucks accounts for the largest share of production costs – and a significant proportion of emissions. Hybrid drive systems offer an effective lever for cost reduction and decarbonisation here.”
Leveraging the idle time OPEX opportunity
At a mine site, a haul truck can be mechanically ready, fully staffed and consuming fuel without moving a single tonne of material. This few minutes of idling may appear insignificant during one shift, yet, across a large fleet operating around the clock, those minutes can become a substantial operating expense.
Reducing unnecessary idling is not as simple as instructing operators to shut down their engines, according to FLANDERS.
“ Haul trucks operate within demanding production cycles and must remain available when work resumes,” it said.“ Shutdown decisions must account for truck status, operating conditions, safety requirements and the needs of supporting systems.”
The challenge for mine leaders is determining how much idling is operationally necessary, how much is avoidable and whether addressing it can deliver enough value to justify the investment.
A deep-pit, hard-rock mining operation in Southern Africa evaluated the FLANDERS Idle Management System( IMS) on a Komatsu 930E-5 to answer those questions using actual operating data.
FLANDERS IMS monitors defined truck conditions and automatically shuts down the engine only when established operating criteria are met. When the truck is required to return to service, the system allows it to restart and resume operation in about two seconds, the company claimed, guaranteeing a hot start, with which the engine is protected against any undesired operating condition.
“ The purpose is not to shut down the engine at every possible opportunity,” FLANDERS said.“ It is to apply shutdown logic consistently when the truck can safely stop consuming fuel without compromising its readiness or normal production requirements.”
The engine will only shut down when certain conditions are met, for example:
• Truck velocity = zero;
• Park brake applied; and
RRPS’ hybrid drive system combines mtu Series 4000 engines with an electric drivetrain
58 International Mining | OCTOBER 2026