Electric mining monster trucks

Image: Caterpillar and BHP are developing electrical heavy-haul trucks to use in its mines. From left: BHP’s Anna Wiley, Mark Pickett and James Agar.

Monster movers: BHP tests electric trucks the size of two-storey house

By Simon Johanson

Australia’s largest miner, BHP, is about to test run heavy-haul trucks with electric motors charged by renewable power in a bid to slash fossil fuel use that accounts for 40 per cent of its carbon emissions.

These huge ore trucks run 24 hours a day, burn vast reservoirs of diesel and are ubiquitous across Australia’s open-pit mines.

James Agar, BHP’s group procurement officer, is charged with cutting the company’s 40 per cent diesel emissions footprint. To do that, he needs to electrify its fleet of 650 heavy-haul trucks, weighing in at about 20 to 25 tonnes each, that currently run on polluting fossil fuels.

The vehicles, with tyres taller than the average person, are the size of a modest two-storey house and carry ore loads between 220 and 400 tonnes. The really colossal trucks mainly operate in BHP and Rio Tinto’s joint Escondida copper mine in Chile.

“We put a target out there that we will be net-zero by 2050 and will be 30 per cent reduced by 2030,” Agar said.

BHP’s Scope 1 and 2 emissions are primarily generated by its operations, and roughly break down to 40 per cent from power use, 40 per cent from diesel fuel and 20 per cent from areas such as fugitive emissions from its coal operations.

The miner has partnered with industrial equipment manufacturers, US-based Caterpillar and Japan’s Komatsu, to develop electric versions of the heavy haulers, pulling out the engine and replacing it with an electric motor and eight-tonne battery.

“Three or four years ago … there was a fairly dogmatic view in some of these industries around defending the diesel engine and all of the decades of IP that had gone into refining, improving and optimising them,” Agar said.

“But the way we saw demand playing out in the future and the types of trucks that we wanted operating on our sites did spark a real sense of innovation and collaboration through our supply chains,” he said.

On a trip to Arizona in August last year, he visited Caterpillar’s proving ground where engineers were working on the shell of a 793 heavy-haul truck that can carry about 300 tonnes.

“In a workshop there was a big gaping hole just underneath the cabin. The engineers were saying; ‘Well that’s where we’re going to put the battery. We’re not quite sure how we’re going to fit it in’,” he said.

Seven months later, Agar was back in Arizona again to witness the same truck complete a full load pick-up at the bottom of a mine pit and dump the ore at the top, all under battery power. The battery currently lasts only about one hour, but can be charged in 15 minutes.

“The trajectory that we’re seeing is really positive around extending that battery life,” Agar said. “We’ve got commitments in place to have trial early learning units of these trucks on our sites around the middle of next year.”

Both manufacturers are working on regenerative breaking for the haulers, so they charge while descending into the pit, and “trolley assist” electric connections, “which is basically like a tram line that the vehicle can connect to, to run a current into the battery while it’s moving,” he said.

The miner will test the trucks in its Pilbara iron ore operations in West Australia next year alongside electric locomotives that will drive its mine-to-port rail haulage lines.

Agar said the company was increasingly replacing its fossil fuel power contracts with renewable energy. “We are looking at how can we build a system that really optimises the flow of the energy electrons from wind, solar, or whatever it is, into the vehicle’s battery and make the most efficient overall mining system,” he said.

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