COPPERTON — The Bingham Canyon "dentist" is going to have to alter its copper extraction method within the next 10-12 years because taking out the bottom of the "tooth" is likely to become more economically difficult.
Kennecott Utah Copper Corp. officials frequently liken their mining process to a dentist extracting a tooth, piece by piece.
"We've mined the crown of the tooth," Louis J. Cononelos, Kennecott director of government and public affairs, said. "We're in the middle of the tooth now."
He said Bingham, located about 17 miles southwest of downtown Salt Lake City and directly west of South Jordan, has been mined by the open pit method since 1906. Unless the copper market surges in coming years, Kennecott is going to have to switch to underground mining sometime in the next decade to remain economically viable.
Chris Robison, vice president and general manager of Kennecott mining and concentrating, agrees.
"We've going to have to go back to our roots," he said, explaining that the original mining in the area was underground.
Robison said Kennecott can take the open pit about 650 feet deeper than it is now before current mining processes become cost-prohibitive. It's not a matter of a lack of copper down there, though. He said a recent drill test showed copper deposits extend to a depth of 100 feet above sea level, or almost a mile deeper than the pit now goes.
Block caving is believed to be the process Kennecott will convert to. "You go under the ore body, mine it underneath and let it drop," Robison said. "You take it out in little feeders so it doesn't cave in on you."
Fortunately, all the old mine tunnels at Bingham Canyon are at much higher levels than Kennecott will be mining.
Robison estimates it will cost Kennecott about $1 billion to convert to underground mining. Most pit employees will need to be retrained, but otherwise he expects the total number of 800 or so employees in the mining process to remain about the same.
"It may be a few less but similar," he said.
Kennecott currently has a total of 2,300 employees. The copper refining process outside the mine would remain the same as it is today.
Robison said Kennecott has an extremely strong safety record now, about 10 times safer than the average open pit mine, and Kennecott doesn't expect that to change much for underground work. He said as many as 150 workers could be underground at one time.
Kennecott currently owns 110,000 total acres, most of the land west of U-111 to the top of the Oquirrh Mountains. Cononelos said much of the land is a buffer between it and the public. The company recently sold a large section of surplus land, near Magna and U-111, and Kennecott officials were surprised how quickly homes, a McDonald's and a KFC restaurant moved in.
Robison said the enormous open pit mine has always been a seasonal tourist attraction and is expected to remain so indefinitely.
For visitors, the Kennecott open pit mine viewing area and visitor center/museum was scheduled to be open for the 2000 season beginning this weekend — weather permitting. The center attracts almost 170,000 visitors a year.