Kennecott Utah Copper said a massive landslide Wednesday night along a geotechnical fault line of the Bingham Canyon Mine, one of the world’s largest mines, in Magna, Utah, USA, about 22 miles from Salt Lake City, was anticipated.
“Movement along the north eastern wall had accelerated in recent weeks and pre-emptive measures were taken to relocate facilities and roads prior to the slide,” said Kennecott in a news release Thursday.
Rio Tinto-Kennecott spokesman Kyle Bennett told Utah news media, “We started noticing movement in that part of the mine in February.” While ground movement is common at the mine, large slides are not, he observed.
“Preemptive measures were taken to relocate employees, facilities and roads for weeks in advance of the event. All remaining employees are accounted for,” the copper company noted.
Power lines and water sources were relocated, along with the mine monitoring control building. The company announced that the visitor’s center, a popular Utah tourist attraction, will not open this year. Kennecott is the second largest U.S. copper producer.
An old truck shop was partially swept away while equipment stationed at the bottom of the mine pit to help remove debris was trapped when the slide buried about two-thirds of the bottom of the pit.
Mine managers anticipated a surface area a couple of thousand feet wide and just as tall was likely to move, but the slide traveled deeper into the mine pit than anticipated, Kennecott General Manager of Operation Readiness, told the Deseret News.
“Our experts will evaluate the extent of the movement over the coming days and ascertain the degree of impact to production,” said Kennecott. “Contingency plans are in place to manage mine operations in the short and long term according to the impact.
In the meantime, all mining has been halted at Bingham Canyon where 163,000 tonnes of copper, 279,000 ounces of gold, and 9,400 tonnes of molybdenum were mined last year. Last year parent company Rio Tinto had approved spending US$660 million over the next seven years to extend the life of the mine from 2018 to 2029.