In 1955, copper mining in the area expanded with the opening of the Berkeley Pit. The mine took advantage of the existing subterranean drainage and pump network to lower groundwater until 1982, when a new owner suspended operations.
After the pumps were turned off, water from the surrounding rock basin began seeping into the pit. By the time an astronaut on the International Space Station took this picture on August 2, 2006, water in the pit was more than 275 meters (900 feet) deep. The water, with high concentrations of copper, arsenic and other metals, is highly acidic and toxic to life.
The Montana Bureau of Mines and Geology estimates the Butte hill produced more than $48 billion in mineral wealth. The costs included 2,300 deaths from mining accidents, not including chronic illness sparked by mine exposure.
The site is the largest Superfund environmental clean-up project in the country! This Superfund site has become a tourist attraction, complete with gift shop.