Rio Tinto has committed to an investment of $108m to study the feasibility of underground development at the Kennecott copper operations in the US.
The investment will be used to facilitate early orebody access and characterisation studies for underground mining.
Rio Tinto Copper CEO Bold Baatar said: “Kennecott holds a range of options to extend our supply of copper and other critical materials, to meet the strong demand being driven by electric vehicles and renewable power technologies.
“The operation is uniquely positioned to supply these emerging markets, with one of only two operating smelters in the United States that also processes concentrates from third parties, a long history delivering high-quality products and significant resources that are yet to be developed.”
Last year, the firm approved a $25m investment to complete a pre-feasibility study to assess the viability of underground operations at the Kennecott mine.
The scope of feasibility study work includes gathering critical geological, geotechnical and hydrogeological data to assess underground development options.
Planned to be completed in 2024, the study will also help in determining the viability of extending the open-pit mining operations at the Kennecott mine beyond 2032.
Rio Tinto said that the potential underground mining, which would be carried out concurrently with open-pit operations, is expected to result in increased copper output.
The firm noted that the Kennecott underground development has declared mineral resources of 20-million tonnes at 3.65% copper and 1.62 g/t gold with further upside potential which is based on drilling.
Rio Tinto is also planning to trial underground battery-electric vehicles to reduce carbon emissions at Kennecott and across its global operations.
As part of this plan, the firm has selected Sandvik Mining and Rock Solutions’ battery-electric haul truck and loader to assess performance and suitability.