SALT LAKE CITY -- New estimates show the landslide that tumbled into Kennecott's mining pit near Salt Lake City may have been North America's largest human-caused slide.
University of Utah geologist Jeff Moore tells The Salt Lake Tribune the slide moved in two major phases at up to 200 mph the night of April 10, separated by an hour and a half.
Earthquake monitors registered the commotion in the open pit at up to a magnitude of 2.4.
Moore says the landslide moved far more material than a pair of earthquake-triggered slides in recent history -- one at Montana's Earthquake Lake in 1959 and the other in 1983 at Thistle, Utah.
Kennecott Utah Copper Corp. believes the April 10 slide was one of the biggest mining-induced slides ever.