"We do know that the flow into the pit extended beyond the scenarios we forecasted, having a greater impact on equipment," the statement reads. "We are confirming there was some damage to equipment and to a building structure in the mine."
There were no injuries.
A Kennecott official on Thursday said there was enough ore and concentrate on hand to continue to produce refined copper for several weeks.
Company spokesman Kyle Bennett said Friday that about 800 employees work in the mine and that the company has set up a hotline for them to receive updates.
Although all employees have been asked to report for work on their shifts, the mine will remain closed until MSHA inspectors and the company's geotechnical experts have deemed it stable.
MSHA spokeswoman Amy Louviere said MSHA personnel are on-site, adding that no one has been inside the mine since Wednesday morning.
MSHA technical support engineers are scheduled to arrive Monday to assess the area.
Louviere said MSHA had been aware of the slide-site's instability since February was alerted to the slide Wednesday at 10:27 p.m. by Kennecott.
"When it comes to the safety of people, there are no shortcuts," Bennett said. "We continue to cooperate with (MSHA) in every way."
Bennett would not speculate on how long it will take for the mine to reopen, but said the slide was completely contained within the mine.
"We had a lot of rain that day that helped reduce dust (from the slide)," he said. "There were no impacts on the surrounding community."
What is known
The breadth of the slide was larger than anticipated.
There was unexpected damage to equipment and a building.
All employees have been asked to report for work on their shifts.
The mine will remain closed until inspectors have deemed it stable.