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EPA issues Record of Decision on South Dakota Superfund site

Release Date: 10/29/2008
Contact Information: Jennifer Chergo, EPA Office of Communication and Public Involvement, 303-312-6601, [email protected] Victor Ketellapper, EPA Remedial Project Manager, 303-312-6578, [email protected]

Cleanup will protect human health and environment from releases of hazardous substances

(Denver, Colo. -- Oct. 29, 2008) The U.S. Environmental Protection Agency, together with the South Dakota Department of Natural Resources, has issued the Record of Decision for the Gilt Edge Mine Superfund Site, Operable Unit 1. OU1 includes the overall contamination at the site, including acid-generating waste rock and mine pits. The Record of Decision describes the final cleanup plan that EPA has selected for OU1. EPA selected the remedy in accordance with Superfund law and regulations. The cleanup is necessary to protect human health and the environment from threatened releases of hazardous substances from the site.

The Gilt Edge Mine Superfund Site is located in the northern Black Hills of South Dakota, in Lawrence County, approximately four miles from the town of Deadwood.
Mining activities began at the site in 1876 and continued intermittently for more than 100 years. The most recent owner of the site, Brohm Mining Company, operated a large-scale, open pit, heap-leach gold mining operation at the site and abandoned it in 1999. These past mining activities caused significant acid rock drainage, which is acidic, metal-laden water that occurs when water and oxygen come into contact with mine waste and exposed rock.

The selected remedy emphasizes site-wide consolidation and containment of mine waste, such as waste rock, spent ore, exposed rock surfaces, amended tailings, sludge and underground mine workings. This will protect people and wildlife from heavy metals and reduce the amount of acid rock drainage generated onsite.

The selected remedy calls for covering onsite consolidation areas to limit water infiltration and acid rock drainage generation. Land use controls will be used to address risks posed by unaddressed contaminant sources. The selected remedy calls for enhanced collection, storage and treatment of acid rock drainage.

“The remedy will reduce the need for water treatment, protect human health and the environment from exposure to mine waste, and reduce the chance of the release of acid rock drainage to Strawberry Creek" said Victor Ketellapper, EPA Remedial Project Manager for the Gilt Edge Superfund Site.

EPA described this selected remedy as its preferred alternative in the proposed cleanup plan issued for public comment in May 2008. The estimated present value cost of the selected remedy is $50 million and will take five to seven years to complete.

The selected remedy follows three interim actions previously implemented at the site. In April, 2001, EPA issued an Early Action Interim Record of Decision to maintain the water treatment at the site. In November, 2001, EPA issued an interim Record of Decision to further improve on the site water treatment. In August 2001, EPA issued another Interim Record of Decision for the Ruby Gulch Waste Dump, addressing the largest acid rock drainage source on the site.

For more information about the Gilt Edge Mine Superfund Site, please visit: https://www.epa.gov/region8/superfund/sd/giltedge

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