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After digging a giant hole in the Oquirrh Mountains for more than a century, Kennecott is going to start mining underground to extend the life of the mine and supply additional copper to a world hungry for more electric power.
And, as part of the effort, the company is testing electric-powered mining machines to keep that underground air safer and cleaner.
“Copper will be incredibly important in the years to come,” said Nate Foster, interim managing director of Rio Tinto Kennecott.
The company is investing $55 million in the move underground. A shaft will be bored into the pit near the bottom, and miners will pursue a layer of copper ore in what is called Lower Commercial Skarn. While most of the ore mined on the surface is less than 1% copper, the underground operation will be removing ore that is closer to 2%. That offsets the higher cost of underground mining.
The company expects to yield around 30,000 tons of high quality copper from the underground mine over the next five years. Open-pit mining will continue, and most of the copper the company produces in the coming years still will come from the surface.
With the move underground, the mine’s life will extend into the 2030s and perhaps to 2040, according to Saskia Duyvesteyn, chief adviser for research and development for copper at Rio Tinto. Mining in Bingham Canyon began in 1903.
Worldwide demand for copper has been growing, largely due to its electrical conductivity. As energy moves away from fossil fuels to cleaner sources, electricity becomes the primary method for transferring and using energy. Electric motors and power lines rely on copper. The average electric vehicle requires two and a half times the copper that a comparable gas-powered car uses.
Lt. Gov. Deidre Henderson, who spoke at a Tuesday ceremony at a viewpoint above the mine, noted that more than 200 minerals are mined in Utah, and it is one of the top 10 states for mineral production.
“In the Beehive state, investments in mining are investments in Utahns,” she said.
Lita Deisley, Corporate Relations Manager for Rio Tinto Kennecott said the company expects to add some contractor workers for the underground project, and a feasibility study “will determine if an expanded underground operation will create additional jobs in the years to come.” The mine currently employs about 2,100 employees and has another 1,500 contractors onsite daily.
Political pressure is mounting to find domestic sources for the materials used to produce electric vehicles. The recently passed Inflation Reduction Act offers big tax breaks to purchase EVs that are considered domestically sourced.
All of the copper mined in Bingham Canyon is used in North America, with the vast majority staying in the United States, Foster said. Small amounts go to Canada and Mexico. The mine supplies about 12% of the copper used in the United States, he said. It also produces smaller amounts of gold, silver and other precious metals. And earlier this year the company started separating and selling tellurium, an element that is useful in making solar panels.
Sandvik, a mining equipment manufacturer based in Sweden, has delivered one loader and two trucks that are electric-powered, with more expected as part of a test to see if they can effectively replace diesel-fueled trucks and loaders. In addition to savings on fuel costs, cost reductions would come from less ventilation required to remove diesel exhaust to keep miners healthy.
“You guys are setting the standard for safety,” said Brian Huff, vice president of technology and product line for Sandvik.
Joe Thomas, a section manager for the Utah Division of Air Quality, noted that Utah industries, including Kennecott, have been cutting emissions faster than cars or other air pollution sources along the Wasatch Front. “This kind of leadership is what we need,” he said.
Brian Moench, president of Utah Physicians for a Healthy Environment, said the mine’s expansion is a concern. He noted that the Kennecott mine is the largest single source of toxic releases in Utah, according to the Environmental Protection Agency’s Toxic Release Inventory.
Moench acknowledged in an interview the need to transition to electric vehicles and other clean-energy technologies, but he said continuing the life of the mine in the Wasatch Front airshed is “not great for public health in the Salt Lake Valley.”
Tim Fitzpatrick is The Salt Lake Tribune’s renewable energy reporter, a position funded by a grant from Rocky Mountain Power. The Tribune retains all control over editorial decisions independent of Rocky Mountain Power.