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National Information |
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Superfund Program
Kennecott South Zone/Bingham
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Site Type: Proposed NPL City: Copperton County: Salt Lake Street Address: 10200 South 8400 West Zip Code: 84006 EPA ID#: UTD000826404 Site ID#: 0800601 Site Aliases: Includes Bingham, Butterfield, Lark, Revere, Yampa, Utah Silver |
Site Description
The Kennecott South site includes the Bingham Mining district in the Oquirrh Mountains, about 25 miles southwest of Salt Lake City. The mountain range represents the west boundary of the Salt Lake Valley. Mining activities at the site began in the 1860s and continue to the present at the large Bingham Canyon open-pit mine. Historic mining operations produced lead, zinc, silver, copper, molybdenum and gold ores.
Kennecott Utah Copper Company (Kennecott) and the Atlantic Richfield Company (ARCO) have cleaned up mine waste dumps, mill tailings, smelter wastes, ground water and surface water, including wetlands, with oversight by state and federal agencies.
In 1990, EPA and the State of Utah found that homes had been built on former flood plains contaminated with high levels of lead and arsenic. Kennecott and ARCO, with EPA, state and community input, conducted studies to determine the nature and volume of the contaminated wastes.
Cleanups involved eight separate subsites. These subsites have been completed:
- Bingham Creek Residential Neighborhoods;
- Bingham Creek Channel;
- Large Bingham Reservoir;
- Butterfield Mine Waste Rock and other canyon wastes;
- Herriman Residential Neighborhoods
- Lark Tailings, Mine Waste Rock & Wetlands;
- South Jordan Evaporation Ponds; and
- Anaconda Tailings.
Cleanup of these sites involved digging up near-surface soil wastes with high lead and arsenic levels, and removal of the wastes to collection and storage areas. More than 25 million tons of mining wastes have been removed. Removal of the surface wastes was completed in 1999.
Site Risk
From 1863, early miners in the area processed gold, silver, lead, zinc and copper, and erected many mills and smelters. They deposited most wastes in the creeks or on the nearby flood plains and valley slopes. The wastes eroded and were deposited downstream. The primary landmark in the district today is the large, open-pit Bingham Canyon copper mine.High levels of lead and arsenic were found in Bingham Creek and Butterfield Creek. Neighborhoods were built on contaminated flood plains and creek beds. Acid waters, from the leaching of wastes, escaped from the collection system and contaminated the ground water under the site. A plume of contamination has spread in the ground water.
The plume begins as a solution of acidic heavy metals and sulfates. In about a mile, the acid is neutralized by the soils, and the metals begin to separate. The sulfates continue through the aquifer to the nearby Jordan River. The contaminants cover more than 72 square miles. Well-drilling permits have been suspended in the area. The site was proposed for EPA's Superfund National Priorities List (NPL) in January 1994.
In 1995, Kennecott, EPA and the State of Utah signed an agreement, saying that Kennecott will continue the cleanups and EPA will defer final listing on the NPL.
| Media Affected | Contaminants | Source of Contamination |
| Soils, sludge, ground water, surface water, sediment, solid waste | Lead, arsenic | Mining wastes |
Cleanup Progress
The long-term action is to cleanup and contain groundwater contamination. A Record of Decision (ROD) was signed in 2000. Cleanup and treatment designs have been conducted in coordination with a Natural Resource Damage Settlement. A water treatment plant began operation in the spring of 2006. EPA finalized on May 21, 2008 a Remedial Design/Remedial Action Consent Decree prescribing future cleanup activities.
The 1994 proposal to list the Kennecott South Zone on the NPL was withdrawn on September 3, 2008 and published in the Federal Register. The State of Utah Department of Environmental Quality (UDEQ), concurs with this request. The request for withdrawal was made pursuant to a Memorandum of Understanding (MOU) between the EPA, UDEQ and Kennecott signed September 1995.
Pursuant to the terms of the MOU, Kennecott agreed to complete numerous cleanup projects for the South Zone Site and the nearby Kennecott North Zone Site. Upon Kennecott's completion of these activities, EPA agreed to take no further action related to final listing of the site and, after construction of all cleanup projects, to proceed to withdraw the proposed listing.
The schedule for future Five-Year Reviews:
| OUs 1, 5, 10, 11 and 24 | June 2009 |
| OUs 3 and 18 | December 2009 |
| OUs 2 and 16 | 2013 |
| OUs 8, 13, 14, 15, 19, 22 and 23 | To be determined |
Community Involvement
A group of stakeholders, representing diverse interests, meets no less often than annually. The group, known as the Technical Review Committee, discusses progress on the site and makes recommendations on future activities. EPA prepares an annual update on Five Year Review activities. (See link below.)
Site Documents
Note: the documents below are Adobe PDF files (about PDF files)Five-Year Review Annual Update December 2007 (PDF, 35 K, 2 pages)
Five-Year Review Report, Kennecott South Zone - June 1, 2004 (29 MB, PDF, Large File!)
Record of Decisions (RODs) for cleanup of this site
Contacts
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