MAGNA — A "significant" landslide occurred Wednesday night at the Bingham Canyon Mine, Kennecott Utah Copper officials confirmed.
The slide occurred around 9:30 p.m. in the northeast section of the mine, Kennecott spokesman Kyle Bennett said. No employees were injured in the slide and its size was not immediately unknown, though it is estimated to be about 2,000-feet wide and 2,000-feet long.
"As of 1 p.m. (Thursday), we are continuing to assess the situation," Bennett said. "We have not been able to determine the magnitude of the slide at this time, but we do know that it is significant."
The copper-mining company was aware of the impending slide and had warned residents near the mine Wednesday that a slide was possible any day. Kennecott engineers had been detecting ground movement as far back as February.
At the time, the movement amounted to just fractions of an inch, but it was enough for the company to close and relocate the mine's visitors center.
Chopper 5 images help mine workers better assess landslide damage
by Jed Boal
MAGNA — Engineers at the Bingham Canyon mine spent their time Thursday using sophisticated technology to monitor the area of a giant landside that broke free Wednesday night. But with the help of KSL's Chopper 5, they now have more specific information that will help them determine their next move.
Ted Himebaugh has worked at the Bingham Canyon mine for the past 36 years; he's been the mine's general manager of operational readiness for the past decade. He's also part of a team that has focused on an impending landslide problem since the earth started to move in February.
"It's the largest slide we've ever had at the Bingham Canyon mine; and I don't know if it's the largest slide in Utah, but it's a big slide," Himebaugh said.
Analyzing KSL's Chopper 5 video Thursday helped him to better understand what happened.
"Where it ended at the bottom, it went a little bit further into the bottom than we planned on," Himebaugh said, pointing to the video screen. "We were not expecting that it would cover that much area in the bottom."
In fact, two-thirds of the bottom of the pit is now covered.
The video also helped Himebaugh spot some of the mine's equipment, including nine partially buried trucks, each of them the size of a small home. But his crew's main objective now is to determine the impact of the damage in the bottom of the pit.
"We didn't know from our modeling that all that material would flow to the bottom," Himebaugh said.
For now, he says the movement of that slide has stopped, but it's too early for his team to determine how soon they can get into that area to assess the damage.
"This is something that we had anticipated," Bennett said of the slide. "We knew the slide was imminent. We had relocated machinery, we had rerouted roads, we had rerouted utilities, we had rerouted buildings."
Over the past few days, engineers started seeing movement of up to 2 inches per day.
"We've seen acceleration rates increase until where we landed (Wednesday night)," Bennett said. "When it reaches 2 inches per day, that's certainly a time when we want to take steps that we have been planning for a number of weeks in order to make sure people are out of the way."
All employees were evacuated in preemptive measures and were safe and accounted for after the slide. Bennett said access to the mine continued to be restricted Thursday and that no employees were being allowed to enter.
"Our job is to safely produce copper. That's our goal," Bennett said. "That's what we want to do. Our employees are critical to that."
The company has not been able to measure the magnitude of the slide and doesn't know if there will be any residual sliding in the days to come. Bennett said experts will continue monitoring the area remotely for other possible slides.
"They're collecting data from our systems, doing visual inspections," he said. "Our monitoring systems identified this as one slide that failed progressively."
Bennett said there did not appear to have been any impacts to the community as a result of the slide.
"The movement has been contained to the mine and presents no threat to the public," he said. "Minimal dust resulted from the slide, in part because of the favorable weather conditions."
Contributing: Shara Park and Mike Anderson