WENATCHEE, Wash. – Deep in the heart of the Okanogan-Wenatchee National Forest, a dramatic sight was unfolding on the landscape above Lake Chelan. For five summers, bulldozers, graders, loaders, and excavators worked to reshape a rock-strewn mountain side, hauling loads of mine waste tailings across a 90-acre cleanup site until, for the first time in more than 60 years, the once-toxic area around the former Holden copper mine was again able to sustain healthy native vegetation and wildlife.
Abandoned in 1957, the Holden Mine contaminated groundwater with five toxic metals including aluminum, cadmium, copper, iron and zinc. These heavy metals washed downstream, polluting water in Railroad Creek, a major tributary to Lake Chelan. The metals also created a hazardous, hard orange coating known as ferricrete on the stream bed.
Unstable waste rock and tailings piles from approximately 10 million tons of mined ore further compounded the problem.
Today, thousands of gallons of contaminated groundwater are treated each day, through an on-site treatment plant. A concrete barrier between the toxic tailings pile and creek will prevent water runoff from the pile and reduce the chance of future contamination.
The remediation effort cost nearly $500 million, which was paid by Rio Tinto – a global mining company which inherited the responsibility for the cleanup through acquisition of a successor company to the original mine owners.
The project was complicated by the mine’s remote location. Holden Village, a religious retreat on the shores of Lake Chelan, closed its doors to thousands of summer visitors it typically hosts in order to provide lodging for work crews during the massive cleanup effort.
Other partners included the Yakama Nation, Washington Department of Ecology and the Environmental Protection Agency, and the USDA Forest Service – which acted as the lead agency overseeing the remediation efforts, because the majority of the cleanup took place on National Forest lands.
Local officials estimate that in addition to cleaning up Railroad Creek and protecting it from future contamination, the restoration effort injected approximately $240 million into the local economy, through hiring of local construction crews and heavy equipment operators.
The project created eight permanent jobs at the water treatment plant, and an additional site manager position in Chelan, Wash.
In September, the Forest Service released a Five-Year Site Review which documents the cleanup effort to date, and outlines future monitoring and additional work that is required.
For more information: Visit www.holdenminecleanup.com
Source information: The Okanogan-Wenatchee National Forest encompasses more than 4-million acres in Washington state, extending from the Canadian border to the Goat Rocks Wilderness. Elevations range from below 1,000 ft. to over 9,000 ft., and the forest is very diverse – from the high, glaciated alpine peaks along the Cascade Crest, through deep, lush valleys of old growth forest, to the dry and rugged shrub-steppe country at its eastern edge. Precipitation varies from more than 70 inches annually along the crest to less than 10-inches at its eastern edge.