Rio Tinto has 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 CO₂ equivalent reduction of up to 45,000 tonnes per year, comparable to eliminating the annual emissions of approximately 9,600 cars.

Rio Tinto US Borax Mine in Boron, California. Source: Rio Tinto

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 as used cooking oil and animal fat waste, the use of Neste MY Renewable Diesel can reduce greenhouse gas emissions by up to 75% over the life cycle of the fuel compared to fossil diesel. Results from the trial showed that a truck running on renewable diesel delivered similar performance and reliability as trucks running on conventional diesel.

Based on these positive results, Rio Tinto US Borax continued to work with Rolls-Royce, Neste, the Environmental Protection Agency, and the State of California to transition fully its heavy machinery fleet onsite to renewable diesel at the end of May 2023. This transition includes all the heavy machinery on the property from haul trucks to loaders; the renewable diesel is even used in blasting.

This conversion to renewable diesel supports Rio Tinto’s global decarbonization objectives, which include a 50% reduction in Scope 1 & 2 emissions by 2030, and a commitment to reach net zero by 2050. The company estimates carbon emissions from the use of diesel in its mobile fleet and rail accounted for 13% of its Scope 1 & 2 emissions in 2022.

In October 2022, Rio Tinto launched a second trial of renewable diesel at Rio Tinto Kennecott’s Bingham Canyon mine in collaboration with Cummins to test renewable diesel in a different operational environment and on different mining equipment. The trial is comparing acceleration, speed, cycle times, fuel usage, and engine inspection reports for two trucks running on renewable diesel versus two trucks running on conventional diesel, complementing the data collected in California.

Neste’s expansion of its Singapore refinery and the joint venture with Marathon in Martinez, CA, will increase Neste’s total production capacity of renewable products globally to 1.9 billion gallons (5.5 million tons) in the beginning of 2024 and make Neste the only global provider of renewable diesel, sustainable aviation fuel, and renewable feedstock for polymers and chemicals with a production footprint on three continents.