PERTH (miningweekly.com) – Diversified major Rio Tinto has launched further trials swapping conventional diesel for renewable fuel in its haul trucks in the US - this time at the Kennecott copper operations, in Utah.

The second trial follows on from an initial trial at the US Borax mine, in California.

“The renewable diesel trials at our US Borax and Kennecott operations could pave the way for Rio Tinto to be the first mining company in the US to operate a fully renewable fleet. It’s a very exciting step towards reducing the carbon footprint of our US operations,” said Rio VP of global procurement Simon Richmond.

The first trial was conducted through 2022 in partnership with Neste and Rolls-Royce. Rio US Borax used Neste MY Renewable Diesel, a hydrotreated vegetable oil made from sustainably sourced renewable raw materials such as used cooking oil and animal fat from food industry waste. Results 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 US Borax will continue to work with the Environmental Protection Agency, the state of California, and engine manufacturers with a goal of having a full transition of the heavy machinery fleet onsite to renewable diesel by 2024, representing an anticipated carbon dioxide equivalent reduction of up to 45 000 t/y.

A second trial has also launched at Rio Kennecott’s Bingham Canyon mine in collaboration with Cummins to test renewable diesel in a different operational environment and on different mining equipment. The seven-month trial, which started in October 2022, will compare 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.

Both trials support Rio’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 account for 13% of its Scope 1 and 2 emissions.