Battery-electric haul trucks represent a significant decarbonisation opportunity for the mining sector and efforts are being made to develop and refine the technology to suit the requirements of large surface mines.
When combined with a renewable electricity source, the electrification of mine haulage can eliminate what is likely the single largest source of carbon emissions from modern mines.
There are about 28,000 large mining haul trucks in operation around the world, which collectively emit more than 68 million tonnes of carbon dioxide every year.
There are many diverse benefits for mines that accelerate battery-operated or electric vehicle adoption, including improved health and safety conditions and reduced operating costs.
A key safety benefit is the reduction of diesel particulate matter, as well as 40 other toxic pollutants emitted from vehicles and generators, which pose short and long-term risks to health ranging from minor effects such as headaches and nausea to serious illnesses like cancer.
Moreover, battery vehicles have about 25 per cent fewer parts, leading to lower overall maintenance costs.
Electrifying mines will require large capital expenditure as well as infrastructure improvements — the power infrastructure investment for electrifying the iron ore industry alone could cost between $30 billion and $45 billion.
The infrastructure improvements needed will include upgraded electric-grid connections, additional onsite substations and networks, and installed or contracted renewable power capacity.
A further challenge to electrification is obstacles in battery-electric vehicle technology — battery technologies need to achieve higher density, lower cost, faster charging, and larger scale to make electric equipment competitive.
However, overcoming these challenges can bring about a host of opportunities for miners.
Electrification can reduce energy costs by as much as 40 to 70 per cent and reduce maintenance costs for mobile equipment by about 30 per cent.
Electric equipment can also allow for steeper ramp designs, lower stripping ratios, faster cycle times, and less frequent breakdowns.
Importantly, a fully electrified mine with renewable power sources will lower its carbon footprint by 60 to 80 per cent.
In May, BHP and Rio Tinto began a collaboration on battery-electric haul truck trials at their Pilbara operations.
It is anticipated ongoing testing, development, and refinement of truck and battery design will occur, to inform the approach for testing a larger number of trucks and the potential deployment of battery-electric fleets into each miner’s operations.
Geraldine Slattery, President Australia at BHP, said operational decarbonisation relied on breakthroughs in technology, and partnerships such as the one with Rio would help drive the industry forward.
She said: “Replacing diesel as a fuel source requires us to develop a whole new operational ecosystem to surround the fleet.
“We need to address the way we plan our mines, operate our haulage networks, and consider the additional safety and operational considerations that these changes will bring.
“This is why trials are so critical to our success as we test and learn how these new technologies could work and integrate into our mines.”
As of last year, BHP was using roughly 1,500 megalitres of diesel in over 1,000 pieces of equipment, with more than half of this used in its truck fleets, and the company has indicated that electrification was its preferred pathway to eliminate this diesel use.
The company’s initial modelling has suggested that battery-electric trucks would cost the same or less to operate compared to diesel.
BHP said it also expected to see overall savings in truck maintenance, as the lack of a diesel engine or mechanical drivetrain meant there were significantly fewer moving parts in electric trucks.
However, the company pointed to a number of unknown costs associated with operating the new technologies, such as the need to replace batteries over a truck’s lifetime and the method of charging, as well as the frequency of relocating the charging system and trolley lines.
Rio Tinto Iron Ore Chief Executive Simon Trott said the collaboration brought together two global miners with two of the world’s biggest haul truck manufacturers to work on solving the critical challenge of zero-emissions haulage.
Trott said: “There is no clear path to net zero without zero-emissions haulage, so it’s important that we work together to get there as quickly and efficiently as we can.
“Testing two types of battery-electric haul trucks in Pilbara conditions will provide better data, and by combining our efforts with BHP we will accelerate learning.”
Brazilian miner Vale earlier this year also decided to test battery-electric trucks and energy transfer systems, with the aim of supporting the company in reducing scope 1 and 2 carbon emissions by 33 per cent by 2030 and net zero by 2050.
A 240-tonne battery-powered truck will be tested at Vale’s operations in Minas Gerais, while an energy transfer solution for trucks will be tested at its operations in Para over the next few years.
Diesel emissions from mine operations account for 15 per cent of Vale’s direct carbon dioxide emissions, and haul trucks are its biggest consumer of diesel.
Jose Baltazar, Director of Engineering for Mine and Plant Operations at Vale, said there had been significant advances in the development of electric truck technology in recent years and those innovations would play an important role in bringing Vale’s net emissions to zero by 2050.
He said: “We are offering our mines in Brazil as a testing ground, with their very specific characteristics, in order to contribute to achieving our goals and building a cleaner mining industry.”