Located in Butte Montana is the Berkeley Pit, which is a toxic waste pool left behind from a former open pit copper mine. This heavily acidic pond is a mile long and half a mile wide, with a “water” depth of 900 feet. Because of it’s highly acidic state the pit water is filled with dissolved heavy metals, so much so that some materials are mined directly from the water itself. The dangerous chemicals found within the liquid includes arsenic, cadmium, copper, sulfuric acid, and zinc.
The copper mine was opened in 1955 and operated by Anaconda Copper, and later by the Atlantic Richfield Company (ARCO). It was closed in 1982 on Earth Day. When it closed, the water pumps from nearby Kelley Mine were turned off and groundwater from surrounding aquifers began filling the pit at a rate of a foot per month. Since the pit’s closure in 1982 the toxic pit level has risen to being within 150 feet of the natural ground water. This is a serious environmental problem. The pit water level is estimated to reach the natural water table by 2020. When that happens the pit water will start to “reverse flow” back into the surrounding groundwater, polluting major water sources such as Silver Bow Creek and Clark Fork River.
Aside from the potentially devastating effects on our water, there is also the damage the pit has had to local wildlife. In 1995 a flock of geese landed in the Berkeley Pit water and 342 of their carcasses were recovered. ARCO, the “pit custodian”, tried denying that the toxic water was the cause of the bird deaths and tried shifting blame to an acute aspergillosis infection caused by grain fungus. The State of Montana did their own lab tests however, an found the bird insides to be lined with burns and festering sores from exposure to high concentrations of copper, cadmium, and arsenic. In 2016, it happened again but the bird death toll grew to be in the thousands.
Berkeley Pit is on the federal Superfund site list, and certain measures like the Horseshoe Bend treatment plant have been put in place to help with the extensive clean up this site desperately needs.
The Pit is listed online as a tourist attraction with gift shop. The fee is small, at only $2 per person. However, when I went to see the pit, it and the shop were closed. By peaking through the windows I was able to conclude that it wasn’t just closed for the day, but for much longer. There was absolutely nothing inside the office or gift shop buildings, and you couldn’t even see the pit without hiking up a hill, sneaking through a gate, and trespassing for a few minutes. So I don’t think anyone else should go out of their way to see this, but my own morbid fascinations wouldn’t allow me to turn away.