Since we're on the topic of open pit mine operation, safety, and planning right here in Wisconsin - - take note that there was in April the biggest landslide at a massive open pit copper mine in Utah in 36 years, and it began with movement measured in a fraction of an inch.
Mine managers anticipated what section of the mine wall was likely to move, a surface area "a couple thousand feet wide" and just as tall, but the slide traveled deeper into the mine pit than they expected, Himebaugh said.
Teams worked preemptively to clear out an old truck shop that was partially swept away, successfully limiting the damage. However, equipment left stationed at the bottom of the mine to help remove debris was caught and buried when the slide moved deeper than predicted.
About two-thirds of the bottom of the pit was buried, Himebaugh estimated.