Superfund Information Systems: Site Profile

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The 300-square-mile Anaconda Co. Smelter site is located at the southern end of the Deer Lodge Valley in Montana, at and near the location of the former Anaconda Copper Mining Company (ACM) ore processing facilities. ACM facility operations included removal of copper from ore mined in Butte from about 1884 through 1980. Milling and smelting produced wastes with high concentrations of arsenic, as well as copper, cadmium, lead and zinc. These wastes contaminated soil, groundwater and surface water with hazardous chemicals. Cleanup is complete at several areas within the site. At these areas, operation and maintenance activities are ongoing. Cleanup is underway at the remaining areas.

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What Is Being Done to Clean Up the Site?

Remedies completed to date are currently protective of human health and the environment. Where remedies are not complete, access is controlled to prevent human exposure to waste and other high arsenic areas. Institutional controls are in place to inform the community of uncontrolled contamination in residential areas as well as providing for prioritization of cleanup where there are children living. Additionally, institutional controls are in place to monitor and regulate domestic wells and to provide for cleanup at the time of development.

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What Is the Current Site Status?

The site consists of multiple areas, referred to by EPA as operable units (OUs).

OU15, Mill Creek: The remedy (PDF) (199 pp, 9.4 MB, About PDF), selected in 1987, included permanently relocating all Mill Creek residents, removing demolition debris and contaminated soils for later disposal, regrading and replanting areas disturbed by relocation/demolition activities, monitoring and maintaining the vegetation, and controlling access to the area. Construction of the remedy finished in late 1988. Operation and maintenance activities are ongoing.

OU11, Flue Dust: The remedy (PDF) (268 pp, 13 MB, About PDF), selected in 1991, included stabilization of about 316,500 cubic yards of flue dust, placement of the treated materials in an engineered repository, long-term maintenance and monitoring, and institutional controls. The remedy required that the repository include a liner, leak detection and collection system, groundwater monitoring wells, and a cap. Construction of the remedy finished in September 1996. Operation and maintenance activities are ongoing.

OU7, Old Works/East Anaconda Development Area: The remedy (PDF) (276 pp, 11 MB, About PDF),, selected in 1994, included placement of engineered covers over waste, treatment of soils, surface water controls, upgrades or repairs to streambank levees, replacement or repairs to bridges, institutional controls, long-term monitoring and preservation of historic features. OU7 consists of six subareas. Construction is complete at five of the six areas. Construction at the sixth area, the Industrial Area, is nearly complete.

OU16, Community Soils: The remedy (PDF) (210 pp, 83 MB, About PDF), for residential soils, selected in 1996 and modified in 2013, included removal of arsenic-contaminated soils and replacement with clean soil. This remedy also called for the cleanup of future residential soils through institutional controls. The remedy for commercial/industrial areas and the active railroad area included placement of engineered covers. Construction of the remedy was finished in 2010. Operation and maintenance activities are ongoing.

The 2013 modification to the Community Soils remedy (PDF) (45 pp, 2.4 MB, About PDF), included cleanup of lead-contaminated residential soil, expanding the institutional controls program and development of an interior dust abatement program. Implementation of this remedy began in 2015 and is ongoing.

OU4, Anaconda Regional Water, Waste and Soil: The remedy (PDF) (825 pp, 175 MB, About PDF), selected in 1998 and modified in 2011 (PDF) (251 pp, 4.7 MB, About PDF) included consolidation of miscellaneous waste materials, placement of engineered covers over waste management areas, treatment of contaminated soils, storm water controls and institutional controls, including the monitoring and regulation of domestic wells in groundwater areas. A Technical Impracticality Waiver for arsenic in groundwater has been applied to large areas of the site. The OU consists of 15 subareas. Remedial action is ongoing at most of the subareas. Over 10,000 acres have been remediated to date. Construction is expected to be completed over the next 10 years.

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EPA’s Involvement at the Site

In 1884, ACM and its predecessors started large copper concentrating and smelting operations at the area presently known as the Old Works. The Old Works was located on the north side of Warm Springs Creek next to the town of Anaconda and operated until about 1901. Around 1902, ore processing and smelting operations began at the Washoe Reduction Works (also called the Anaconda Smelter, the Washoe Smelter, the New Works, and the Anaconda Reduction Works) on Smelter Hill, south of the Old Works and east of Anaconda. In 1977, Atlantic Richfield Company (Atlantic Richfield) purchased ACM. Operations at the Anaconda Smelter ceased in 1980; the smelter facilities were dismantled soon thereafter. EPA placed the Anaconda Co. Smelter site on Superfund program’s National Priorities List (NPL) in September 1983. EPA is the lead agency with Atlantic Richfield conducting site activities through administrative orders.

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Sampling and Monitoring

Residential soil sampling is expected to begin in 2016 and continue through 2018. Sampling is prioritized based on the results from previous sampling and/or whether there are children living at a property. Additional sampling may also be conducted by request of landowner.

Details of the sampling and cleanup are provided in the 2015 Residential Soils/Dust Remedial Action Workplan for OU 16 (PDF) (501 pp, 30.2 MB, About PDF

Domestic wells will also be monitored as overall site ground and surface water continues at the site.

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