Bingham Canyon Mine, Utah
Located 20 miles outside Salt Lake City in the Oquirrh Mountains, the Bingham Canyon copper pit is about 2.75 miles wide and 4,000 feet deep. Two Empire State buildings stacked one on top of the the other wouldn’t reach the top. By 2015, the mine will be 500 feet deeper, and a third Empire State building will fit inside. The terraces inside the pit, which provide a base for the digging equipment and also stabilize the slopes, can be more than 80 feet high.
Berkeley Pit, Butte, Montana
This former copper mine operated between 1955 and 1982. An elaborate system of pumps and drains kept the local water level low enough for mining. Today, the 1,780 foot-deep pit is filled with around 900 feet of contaminated water filled with metals and chemicals such as arsenic, cadmium, pyrite, zinc, copper and sulfuric acid. The water can be as acidic as battery acid, and copper can actually be “mined” directly from the water. Currently, the 1-mile-by-0.5-mile pit is listed as a federal Superfund site with the potential to contaminate surrounding ground water, and, surprisingly, is also a tourist attraction, complete with gift shop and $2 admission fee.
