BUTTE (Montana): Long before Hurricane Katrina inundated New Orleans with what officials describe as a dangerous toxic soup, Montana’s mining capital struggled to deal with a massive watery hazard. As bad as the sewage and chemical infested water around New Orleans may be, the Berkeley Pit, a toxic lake filling a 2.4 km by 1.6 km (1-1/2 by 1 mile) open pit mine in Butte may pose an even greater long-term ecological risk.
The site, which includes land near the lake, is the largest Superfund environmental clean-up project in the country in terms of area. The Superfund programme, created in 1980 and run by the US Environmental Protection Agency, seeks to clean up the worst US hazardous waste sites.
Unlike the sudden devastation of the Gulf Coast floods, the Berkeley Pit mess was many decades in the making, a legacy of the demand for copper wire spurred by electrification that made Butte America’s mother lode of copper, generating an estimated $48 billion in mineral wealth.
The “Copper Kings” of the Butte mines made vast riches starting in the 1870s. By 1955, Anaconda Mining Company decided it was most economical to engage in open-pit mining rather than to continue digging a maze of underground shafts.
The Atlantic Richfield Company, which is now owned by BP, bought Anaconda in 1977, and ended active mining in the Berkeley Pit in 1982.
Since then, highly acidic underground water has continuously seeped into the pit from higher land, creating a rust-coloured lake.
The Berkeley Pit, a remnant of what was once called “the richest hill on Earth”, has also become Butte’s top tourist attraction where visitors pay a small fee to enter a viewing platform and read about the lake’s history. But if its lake rises above a certain level, it will ruin the town’s ground water.
“The plan is to continue with pumps to keep the water below that level and then treat the water that they pump out and that’s going to have to go on until the end of time,” Montana Governor Brian Schweitzer said in an interview.
The water, with high concentrations of copper, arsenic and other metals, is dangerous enough that officials will warn off birds with gunfire, for a stay at the lake could prove fatal, as in 1995 when 342 snow geese died.—Reuters
