The slide occurred in the form of two
huge rock avalanches at 9:30 p.m. and 11:05 p.m. MDT at Rio Tinto - Kennecott Utah Copper's open - pit Bingham Canyon Mine, 20 miles southwest of downtown Salt Lake City.
The researchers don't know why the slide happened as two
rock avalanches instead of one, but Moore says, «A
huge volume like this can fail in one episode or in 10 episodes over hours.»