On 10 April 2013, Kennecott's Bingham Canyon copper mine situated in the Oquirrh Mountains of Utah, experienced collapse of one wall of the open pit mine. In EarthSky's EARTH, Deanna Conners provides a short overview in, 'Today in science: Bingham Canyon landslide'.
From Deanna's account: 'The April 10, 2013, landslide at Bingham Canyon mine contained enough debris to bury New York City’s Central Park 66 feet (20 meters) deep, according to a University of Utah study. The slide happened in the form of two rock avalanches 95 minutes apart. The first rock avalanche included grayer bedrock material seen around the margins of the lower half of the slide. The second rock avalanche is orange in color, both from bedrock and from waste rock from mining. The landslide also triggered 16 small earthquakes. Photo by Kennecott Utah Copper, via University of Utah.'