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Case Summary: EPA and Forest Service Issue UAO at the Holden Mine Site

On June 26, 2012 the EPA and the United States Forest Service (FS) jointly issued a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, commonly known as Superfund) Section 106 Unilateral Administrative Order (UAO) to Intalco Aluminum Corporation for cleanup work at the Holden Mine Superfund Site, located in Okanogan-Wenatchee National Forest, Wash.

This UAO was issued jointly because the site includes both federal and private property. This is the first UAO that the EPA was asked to concur on pursuant to Executive Order 13016 (EO 13016) that was proposed as a UAO issued jointly between EPA and a Federal Resource Manager. EO 13016 delegates certain Superfund authorities under section 106 of CERCLA to a Federal Resource Manager. The estimated cleanup costs for the site is is $107 million. The FS serves as the lead agency, in cooperation with the EPA and Washington State Department of Ecology.

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Information about the Company

Intalco Aluminum Corporation, a Rio Tinto subsidiary and successor to the original Howe Sound mining operation, manufactures aluminum ingots and stock for casting facilities. It produces painted aluminum sheets; and processes its sheets into various products, such as aluminum foil, cable television conduit, roofing materials, stadium seating, and window casings.

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Information about the Holden Mine Superfund Site

Holden Mine is an inactive underground copper mine on the eastern slopes of the Cascade Mountains. Major features of the mine area cover about 125 acres. The mine extends from the former mine operations along an approximately 10-mile reach and is located along Railroad Creek about 50 miles north of the town of Chelan and 10 miles west of Lake Chelan. Between 1938 and 1957, the Howe Sound Mining Company mined copper, zinc, gold and silver from the Holden Mine. 300,000 cubic yards of waste rock and about 8.5 million tons of mine tailings covering about 90 acres were left at the site. Since mining operations ceased, the mine partially filled with water. This water becomes contaminated as acid mine drainage that drains into Railroad Creek at concentrations toxic to aquatic life.

The hazardous substances at the site include iron and aluminum compounds, arsenic, cadmium, copper, zinc, and lead. Contamination from the mining operation also results in depressed pH, and to a lesser extent, petroleum hydrocarbons. More information on the Holden Mine Superfund Site cleanup is available from the U.S. Forest Services website.

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Overview of the Unilateral Administrative Order

The joint UAO requires Intalco Aluminum Corporation to conduct the remedial design and remedial action at the Holden Mine Site, by implementing the selected cleanup remedy identified in the January 2012, Record of Decision for the project. The remedial action entails mainly involves the capture and treatment of contaminated water, and consolidation and cap on tailings, waste rock, and impacted soil. In addition, Intalco Aluminum Corporation is required to maintain a financial assurance performance guarantee in the initial amount of $112 million.

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For more information contact:

Jennifer MacDonald
U.S. Environmental Protection Agency
Region 10
1220 Sixth Avenue, Suite 900
Seattle, Washington 98101

Douglas Dixon

David Smith-Watts

Melissa Gibbons

Headquarters address:

U.S. Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, D.C. 20460

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