After 110 years, Kennecott going back underground

John Rogers 

More than 110 years ago, the Kennecott Copper Mine in Salt Lake County’s Bingham Canyon began extracting copper ore from an underground mining operation. Abandoning the underground method early in its history, the mine would become known as the world’s largest man-made excavation and deepest open-pit mine in the world.{mprestriction ids="1,3"}

Now Rio Tinto, the owner of the Kennecott mine, has announced that the operation is going back underground. The subterranean mining project will begin immediately and is expected to produce its first ore early in 2023, with full production expected later next year, according to Nate Foster, interim managing director of Rio Tinto Kennecott.

“We’re innovating and we’re closer to writing the next chapter within Kennecott’s history,” said Foster at an event announcing the revised operations in Bingham Canyon.

Rio Tinto has approved a $55 million investment in development capital to start the underground mining and expand production at the Utah operation.

Underground mining will initially focus on an area known as the Lower Commercial Skarn, which company officials said will deliver a total of around 30,000 tons of additional high-quality mined copper through 2027. The copper will be processed at the existing Salt Lake County facilities of Kennecott, one of only two operating copper smelters in the United States. The ore mined underground will be refined alongside that produced from ongoing surface mining operations, the company said.

Foster also noted that nearly all of the copper produced by Kennecott’s Utah operation stays in North America.

Rio Tinto also announced that the underground project will be using electric vehicle technology on a trial basis to determine the feasibility of using the non-polluting vehicles in mining operations. Kennecott is partnering with Swedish mining equipment technology company Sandvik in the effort. 

“These vehicles are safer, cleaner, more efficient and less noisy than traditional vehicles used underground,” Foster said. He added that success in the electric vehicle trial could mean a change in equipment for Rio Tinto’s future mining projects around the world in addition to the Utah mine.

“This investment will allow us to quickly bring additional volumes of high-quality copper to the market and build our knowledge and capabilities as we evaluate larger scale underground mining at Kennecott,” said Rio Tinto Copper CEO Bold Baatar. “We are progressing a range of options for a significant resource that is yet to be developed at Kennecott, which could extend our supply of copper and other critical materials needed for electric vehicles and renewable power technologies.”

“Trialing underground battery electric vehicles is an exciting step in our work to create a safer workplace for our employees, increase the productivity of the mine and reduce emissions from our operations,” Baatar said. “We look forward to seeing their potential for deployment.”

Foster said existing underground infrastructure is currently being extended to enable early access to the next underground resource and undertake characterization studies for the new phase of mining. He also said feasibility studies are underway to extend open pit mining at Kennecott beyond 2032.

Rio Tinto’s Utah Kennecott operations has more than 2,000 direct employees and contributes to thousands of more jobs in the area.{/mprestriction}