On Dec. 28, 2008, an earthen retaining wall broke at the Tennessee Valley Authority's coal-fired Kingston Fossil Plant near Harriman, Tenn., releasing more than 1 billion tons of toxic sludge into two watersheds. The 300-acre flow of wet coal ash inundated homes and farmland, spreading heavy metals into the areas. Cleanup continues today and water monitoring is ongoing. As in western Hungary, environmentalists also worry about what happens to the metals and other contaminants left behind in the dusty residues after the water evaporates.
On Feb. 26, 1972, a rain-drenched impoundment dam in Logan County, W.Va., belonging to the Pittston Coal Company, unleashed a 10- to 20-foot-high wave of blackened water onto the communities of Buffalo Creek Hollow. The 132 million gallons washed out two other impoundment dams in the disaster that claimed 118 lives, left seven missing and injured 1,000 more. It destroyed more than 500 homes and left 4,000 people homeless, according to the official report to West Virginia Gov. Arch A. Moore Jr.
Robert Gardner, a campaigner for Greenpeace, said in an interview Thursday that 137 coal ash sites in 34 states have been identified by three nonprofit environmental groups: Environmental Integrity Project, the Sierra Club and Earthjustice, as releasing toxic metals and other contaminants into ground water or surface water. These sites, in rural and urban areas alike, often feature tall coal-ash piles surrounded by protective berms, or coal ash ponds, which could give out.
Gardner cited the ash treatment dam at the Cane Run generating facility in Louisville, Ky., very close to a street of working-class homes in that southern city. The federal Environmental Protection Agency considers the 79-acre Cane Run pond a "high-hazard" site, where a dam breach would cost lives. He said that the dam owner has proposed a 16-story ash impoundment expansion for 5.7 million cubic yards of coal waste.
The EPA in late August held the first in a series of regional hearings about a pending rule to regulate the handling of coal ash waste from power plants; the next is scheduled for Oct. 27 in Knoxville, Tenn.
But coal isn't the only mining industry whose waste products pose potential hazards.
Outside Salt Lake City, the Bingham Canyon mine operated by Kennecott Utah Copper is America's biggest open pit mine, as well as the largest man-made excavation on earth, so large that it's visible from space. The mine, which contains copper, molybdenum, and precious metals, is 2.5 miles across, rimmed by huge piles of waste, situated in a seismically active area.
Much of the waste has been moved into a nearby mine tailings pond, which is 220 feet high, covers about 14 square miles and holds 2 billion tons of mine tailings -- the leftovers from extracting valuable metals from ore.