Rio Tinto is carrying out a seven-month trial at its Kennecott copper operation in Utah to 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.

Rio Tinto said it 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 reported that it had 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.”

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 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 said 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.

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 stated global decarbonization 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.

In a related development, Rio Tinto, along with BHP, Shell, ABB, and GHD, has joined a newly launched industry task force sponsored by CharIN (Charging Interface Initiative) and ICMM to address technical bottlenecks around the interoperability of battery-electric charging systems for the roll-out of zero emission greenhouse gas (GHG) mining vehicles. CharIN is a global association focused on promoting interoperability based on the Combined Charging System (CCS) as the global standard for charging vehicles of all kinds. The International Council of Mining and Minerals (ICMM), comprising more than two dozen major corporate members representing about a third of the global mining industry by production and 35 regional and commodity associations, was established in 2002 on the premise of improving sustainable development in the mining and metals industry.

Taskforce participants, according to the sponsors, will define requirements, pilot, and test the technical capabilities of the interoperable ruggedized charging solutions in mining environments. This will aid in defining the requirements for both a higher power stationary charging plug and a dynamic (in-motion) charging interface for use on mining sites.

This article was published previously in the May 2023 edition of Engineering & Mining Journal (E&MJ).