Kennecott to begin moving ore again in days after massive slide
By Steven Oberbeck
The Salt Lake TribuneFirst published Apr 25 2013 09:13AM
Bingham Canyon • Kennecott Utah Copper expects within days to begin moving newly dug ore to its crusher but it will be next year before the company restores full production following a massive landslide that halted operations.
Only a small amount of ore mining will take place initially, Kennecott President and Chief Executive Kelly Sanders said Thursday during a media briefing at the mine. He added it won’t be enough to provide customers with all the refined copper they need over the next several months.
"It takes about 60 days from the time we mine [ore] to get all the way to refined copper," Sanders said. "So clearly we understand what the impact will be in terms of [supplying] final refined product."
What isn’t clearly understood is how the April 10 landslide — which Sanders termed one of the largest in mining history — will affect the company’s work force.
Kennecott projects 2013 production at its Utah facilities will be down 50 percent compared with last year. But the company has not said how lower production will impact its 2,100 employees. Sanders said he will not discuss staffing levels without first discussing and consulting with the unions that represent Kennecott’s workers.
In 2012, Kennecott produced 163,200 tons of refined copper, 9.4 tons of molybdenum and 279,000 ounces of gold from ore dug up by its giant shovels and trucked out of the Bingham Canyon pit, which is the world’s largest excavated hole. The open-pit mine annually accounts for between 1 percent to 2 percent of the world’s mined copper production, or approximately 25 percent of the copper used in the U.S.
Kennecott is intent upon restoring full production as quickly as possible while maintaining a safe work environment, Sanders said. He anticipates a long-term plan will be in place within 120 days to take the mine from 50 percent to full production but said operations won’t be fully restored until next year.
The first step in that plan will be restarting ore mining and moving ore to the crusher, where the copper-containing rock is pulverized in one of four huge grinders.
"We’ve inspected the crusher and the conveyor system in the tunnel and they were not impacted by the slide," Sanders said. "We have turned the crusher on to ensure that it will work effectively and we have ore available. What we are waiting on is ourselves. We want to be certain that the area we want to operate in is safe."
Kennecott spokesman Justin Jones said the company’s goal within the month is to have one of its four grinders crushing ore on an around-the-clock schedule and sending that pulverized ore on its five-mile trip to the concentrator, which represents the second step in Kennecott’s production process.
The concentrator takes crushed ore and mixes it into a slurry that then is piped to flotation cells where it is mixed with reagents to produce a bubbly froth. Copper, gold, silver and other metals adhere to the bubbles, which float over the sides of the flotation cells. Kennecott then collects and filters that material, which is called concentrate. The concentrate, which contains about 26 percent copper and by-products such as gold and silver, is then sent through a pipeline to the company’s smelter for further processing.
With a shortage of concentrate for smelting looming, Matt Lengerich, the general manager of the Bingham Canyon Mine, said the company is considering buying concentrate from other copper mines. But he noted those discussions still are preliminary.
The massive landslide two weeks ago sent 165 million tons of rock crashing down into the mine, filling most of the bottom of the pit as deep as 300 feet. To put that slide in perspective, Lengerich pointed out that Kennecott’s original production plan called for the company to move some 260 million tons of ore and non-copper bearing rock in all of 2012.
Sanders said as Kennecott begins to move forward it will need to look at all of its operating costs, including the cost of its work force. But he added that company employees so far have been working to help lessen the impact of reduced production.