The hill slide at Kennecott Copper Utah's Bingham Canyon Mine is estimated to be about 2,000-ft wide and 2,000-ft long, but thanks to precautions taken before the slide there were no injuries reported.
Kennecott Utah Copper was aware of the impending slide from ground detection studies and warned nearby residents of the mine that the slide could happen. When the first ground movement was noticed, in February, the company closed and moved it visitors center, despite the fact that the first movements detected were just fractions of an inch.
"As of 1 p.m. (Thursday), we are continuing to assess the situation," Kyle Bennett, spokesman for Kennecott Utah Copper said. "We have not been able to determine the magnitude of the slide at this time, but we do know that it is significant."
Utah news station KSL reported on the slide and images of the slide can be seen here.
"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," 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."
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."