FUELS & OILS
energy demanding machines. At bauma 2025, Liebherr is presented its concept of an ammonia engine, which will offer a high efficiency density power in line with the requirements of the mining industry. Liebherr and Bruno Generators Group are working together on a feasibility study that focuses on green ammonia’ s viability as the principal fuel for low and zero emission power generation solutions for the mining sector.
Vale’ s progress on renewable diesel and ethanol
In October 2024, Brazilian iron ore mining giant Vale and oil & gas major Petrobras announced the signing of a Strategic Alliance Agreement to supply products with a focus on competitiveness and advancing Vale’ s decarbonisation agenda. This agreement, which reflects the natural evolution of the protocol of intentions signed by the companies in September 2023, establishes conditions for testing and potentially marketing three strategic products: co-processed diesel with renewable content, natural gas and bunker with 24 % renewable content. The products included in the agreement were defined on the basis of joint studies between the companies.
Diesel R5 is an S10 diesel with 5 % HVO in its composition. It is produced by coprocessing oil derivatives with raw materials of plant origin, resulting in a product with identical technical specifications to mineral diesel and 60 % less carbon intensity in the renewable portion.
The first action under the agreement has already begun with the supply of diesel with renewable content( Diesel R5) by Petrobras. The product began to be supplied to Vale in the second week of October 2024 to carry out industrial-scale tests on the Vitória-Minas Railroad and at the Fábrica Nova mine, in the Mariana Complex( Minas Gerais, Brazil), on a Caterpillar 789C mining truck.
Petrobras is a pioneer in the development of diesel with renewable content. It is a product obtained by coprocessing in Petrobras refineries and does not require any alterations to vehicles or storage structures in order to be used. The product also requires a mixture of biodiesel ester, according to the percentage defined by current regulations.
Over in Indonesia, in August 2024, PT Vale Indonesia Tbk( PT Vale) said it was continuing to strengthen its commitment to supporting Indonesia’ s green energy transition. In collaboration with Pertamina Patra Niaga, PT Vale became one of the first mining companies to adopt HVO, in the form of Pertamina Renewable Diesel, in its heavy equipment operations.
The use of HVO has been implemented in two heavy-duty trucks, a Komatsu HD785 and a Caterpillar 777, each with a 100-ton capacity. These trucks underwent a monthlong trial from October 15 to November 14, 2024. The results of the trial demonstrated a significant improvement in operational efficiency, along with a remarkable 70 % reduction in carbon emissions. Moreover, the use of HVO also led to an 80 % decrease in greenhouse gas emissions compared to conventional diesel.
In June 2025, Vale announced that partner Cummins Inc had started the successful commissioning of a new ethanol fuel test cell, marking a significant milestone in both companies’ joint project with Komatsu to develop an ethanol / diesel-powered surface mining haul truck aimed at reducing greenhouse gas emissions. This achievement underscores the three companies’ shared commitment to decarbonising the mining sector and advancing sustainable energy solutions.
Announced in July 2024, the dual fuel program aims to retrofit existing diesel engines in Komatsu haul trucks to operate on both ethanol and diesel, significantly enhancing sustainability. These modified 230 – 290-ton haul trucks – the first vehicles of this size to run on ethanol in the tank – will be able to use up to 70 % ethanol, potentially lowering CO 2 emissions footprint by up to 70 %. QSK60 Engine testing is expected to run until 2026 before field tests begin at Komatsu’ s facilities.
Carlos Medeiros, Vale’ s Executive Vice President of Operations, stated:“ We continue to make progress on our decarbonisation projects, reinforcing Vale’ s commitment to this issue. Ethanol is a priority input to achieve our goal of reducing the use of diesel in our operations while keeping reliability and operational excellence.”
Vale has set a target of reducing its scope 1 and 2 greenhouse gas emissions by 33 % by 2030. Among mine equipment, the haul truck is one of the biggest consumers of diesel and therefore a major emitter of greenhouse gases. The election of ethanol as an alternative to diesel is justified because it is already a widely adopted fuel in Brazil, with an established supply network.
“ Ethanol / methanol diesel dual fuel systems offer significant benefits to the mining industry, including the realisation of up to ~ 70 % decarbonisation – lowering harmful emissions such as carbon dioxide, nitrogen oxides, and particulate matter – while continuing to meet comparable productivity and performance requirements,” said Luke Mosier, Cummins Innovation Program Leader.“ More than that, miners who utilise alternative fuels can utilise their existing infrastructure and leverage their current fleet, facilities and personnel.”
Cummins low carbon fuel test cells accommodate a wide range of high horsepower engines – from 38L to 95L fuel capacity – and ensure seamless transition of a variety of alternate fuel types for varied testing scenarios. The specialised facilities also maintain a high precision environment to deliver accurate emissions with reliable data and provide safe storage conditions to prevent contamination and maintain fuel quality.
Vale is also working closely with Caterpillar on dual fuel as it also has a large Caterpillar fleet. In February 2025, the two companies signed a new five year framework agreement- dual-fuel haul truck to be powered by ethanol and diesel that is under development by Caterpillar would initially equip trucks capable of carrying 240 tons of ore. In the future, the technology may be extended to trucks with a capacity of 320 tons. In total, there are more than 150 of both models in operation at Vale. Initial testing is to be completed at Caterpillar’ s facilities in the US followed by additional validation and testing of dual-fuel trucks at Vale’ s operations.
Rio Tinto leading the way at Boron and Kennecott
In its 2025 Climate Action Plan, Rio Tinto states:“ We continue to work with BHP, Caterpillar and Komatsu to accelerate the development of battery-electric haul trucks. In addition we have invested in the deployment of 8 smaller-sized battery-swap electric trucks at Oyu Tolgoi. However, we do not expect wide-scale deployment if large-scale electric trucks before 2030 due to technology maturity globally. Given this slower pace of technology development, we are developing alternative solutions in the interim. We have invested in renewable diesel with Kennecott switching to this in 2024, following the successful transition at our Boron mine in California the year before. We have also started to develop our own biofuel supply with an investment in 3,000 hectares in Queensland, Australia to plant Pongamia saplings.”
In more detail, in June 2023 Rio Tinto successfully completed the full transition of its heavy machinery from fossil diesel to renewable diesel at its Boron, California operation, making it the first open pit mine in the world to achieve this milestone. The change to renewable diesel brings an anticipated CO 2 equivalent reduction of up to 45,000 t per year, comparable to eliminating the annual emissions of approximately 9,600 cars.
An initial trial of switching fossil diesel to renewable diesel in a US Borax haul truck was conducted through 2022 in partnership with Neste and Rolls-Royce. Rio Tinto US Borax used Neste MY Renewable Diesel during the trial. Made from sustainably sourced, 100 % renewable raw materials such
International Mining | JULY 2025