Superfund Information Systems: Site Profile

Superfund Site:

KENNECOTT (NORTH ZONE)
MAGNA, UT

Cleanup Activities

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Background

The Kennecott (North Zone) site is located in Magna in Salt Lake County, Utah. Since 1906, the site processed copper, lead, zinc, molybdenum, arsenic, gold and silver-bearing ores. The resulting wastes contain hazardous substances, including heavy metals. Soils and sludge are contaminated, as are surface and groundwater, which affect wetlands between the site and the shore of the Great Salt Lake. Cleanup is ongoing.

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What Is Being Done to Clean Up the Site?

The site is being addressed through federal, state and PRP actions.

EPA has conducted five-year reviews at the site. These reviews ensure that the remedies put in place protect public health and the environment, and function as intended by site decision documents. A five-year review was completed on June 17, 2014 and concluded the remedies are not protective in the long term because operation and maintenance and institutional control issues need to be resolved.

In 1994, EPA proposed the site for listing on the Superfund National Priorities List (NPL). Kennecott, the potentially responsible party (PRP), the Utah Department of Environmental Quality (UDEQ) and EPA signed an agreement stating that Kennecott would continue the cleanup and EPA would postpone finalizing the site on the NPL.

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What Is the Current Site Status?

The site consists of multiple areas, referred to by EPA as OUs. There are eight OUs and cleanup and monitoring is ongoing. The OUs are as follows:

  • OU8 Waste Water Treatment Plant and Sludge Ponds
  • OU9 Magna Soils
  • OU13 Smelter and Acid Plants
  • OU14 Refinery
  • OU15 Mill and Tailings Pond
  • OU19 Smelter Fallout
  • OU22 Great Salt Lake Wetlands
  • OU23 North End Groundwater

The site’s long-term remedy, selected in 2002, included in-place treatment of selenium-tainted groundwater coupled with collection of contaminated spring and well water for industrial use; demolition of unneeded facilities; characterization of underlying soils and removal of contaminated soils to an engineered repository; continued use of the Arthur Step-back Repository to store contaminated soils following demolition activities and/or following facility closure; development of a monitoring plan to evaluate progress toward ecological improvement; and mapping of locations of buried wastes and locations where future unrestricted land use is not appropriate. Remedy design and implementation is ongoing.

Site cleanup has also included removal actions, or short-term cleanups, to address immediate threats to human health and the environment. These actions primarily removed or capped wastes contributing to groundwater contamination.

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EPA’s Involvement at the Site

Since 1906, the area has been used to process copper, lead, zinc, molybdenum, arsenic, gold and silver-bearing ores. The wastes produced contain contaminants that can be hazardous, including heavy metals.

Today, Rio Tinto Kennecott Copper (Kennecott), the site’s potentially responsible party (PRP), maintains active mining operations on or near all of the operational units (OUs). Kennecott recently needed to expand its tailings storage area and purchased land along the south shore of the Great Salt Lake. These were degraded lands due to salt evaporation ponds, overgrazing, waste dumping and off-road vehicle use. The wetlands received discharges either directly or indirectly from the other site OUs. Kennecott turned what once had been an abused wetland into a shorebird and waterfowl reserve along the south shores of the Great Salt Lake. Birding groups, schools and university research teams observe and study life in this wetland, which has become a haven for birds and an important education and scientific resource.

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