Rio Tinto is progressing plans to swap conventional diesel for renewable fuel in haul trucks at its U.S. operations to reduce the carbon footprint of its fleet. 

The company successfully completed a renewable diesel trial at its U.S. Borax mine in Boron, California, and is now conducting a second trial at the Kennecott copper operations in Salt Lake City, Utah, to determine the suitability of renewable diesel for open pit haulage. 

Rio Tinto Vice President of Global Procurement Simon Richmond said: “The renewable diesel trials at our U.S. Borax and Kennecott operations could pave the way for Rio Tinto to be the first mining company in the U.S. to operate a fully renewable fleet. It’s a very exciting step towards reducing the carbon footprint of our U.S. operations.”

U.S. Borax trial delivers positive results

The first trial was conducted through 2022 in partnership with Neste and Rolls-Royce. Rio Tinto U.S. Borax used Neste MY Renewable Diesel, a Hydrotreated Vegetable Oil (HVO) 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 Tinto U.S. 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 CO2e reduction of up to 45,000 metric tons per year.

Kennecott tests renewable diesel in different conditions

A second trial has also launched 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 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 Tinto’s global decarbonization objectives, which include a 50 per cent 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 account for 13% of its Scope 1 & 2 emissions.