Berkeley Pit, the Pit of Poison

The Berkeley Pit is an abandoned open pit copper mine located in Butte, Montana, United States. It is over a mile long, half a mile wide, and over a third of a mile deep. During its heydays, Berkeley Pit supplied a sixth of the world's copper needs, and during the 27 years of operation approximately 320 million tons of the ore were extracted enough to “pave a four-lane highway four inches thick from Butte to Salt Lake City and 30 miles beyond,” according to Pitwatch.org. The once thriving copper mines of Butte earned the district the title of “the richest hill in the world.” Today, the pit is filled with nearly 30 billion gallons of highly acidic water laced with toxic chemicals like arsenic, cadmium, zinc, and sulfuric acid that threaten the environment and the water supply of the nearby town of Butte. Photo credit Rich copper deposits were known at Butte since the early 1870’s, although development was delayed due to lack of adequate transportation required to bring the ore to smelters. Without the necessary rail lines and recovery facilities, Butte’s copper ore was sent to Swansea, Wales for processing. By the late 1880s, new railway lines were laid connecting Butte with the Union Pacific out of Ogden, Utah. By the time electricity was discovered, Butte had all the infrastructural components needed to meet the burgeoning demand for copper needed to electrify cities. From 1892 until 1903, the Anaconda Mine was the largest copper-producing mine in the world accounting for 20% of all US copper production. For nearly 70 years, mining for copper was done by dropping shafts into the earth or boring tunnels through the hills. As price of copper soared, Butte needed more efficient mining techniques, and in 1955, the area introduced open-pit mining in the form of Berkeley Pit. Within the first year of operation, the Berkeley Pit extracted 17,000 tons of ore per day at a grade of 0.75% copper.