Diversified miner Rio Tinto has achieved an historic milestone at the Boron mine, in California, which has become the world’s first openpit mine to operate a fleet running entirely on renewable diesel.

“This is an excellent example of what happens when internal and external partners collaborate towards a carbon reduction goal,” said Rio Tinto Minerals CEO Sinead Kaufman.

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 with fossil diesel, Rio Tinto states.

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 fully transition 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, and the renewable diesel is even used in blasting.

This conversion to renewable diesel supports Rio Tinto’s global decarbonisation objectives, which include a 50% reduction in Scope 1 and 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 and 2 emissions in 2022.