RDU 15 – Mount Haggin Uplands

Established in 1998, the Anaconda Regional Water, Waste & Soils (ARWWS) Operable Unit (OU) is the largest and most diverse Operable Unit in the Anaconda Smelter NPL site. As a result, the OU was separated into fifteen Remedial Design Units (RDUs) based upon factors such as location, source and type of contamination, and remedial needs. Click here for more information about the ARWWS OU.

Situated south of Anaconda and southeast of Mill Creek Road, RDU 15 – Mount Haggin Uplands is located entirely within the state-owned Mount Haggin Wildlife Management Area (WMA). As a dedicated Wildlife Management Area, the lands within RDU 15 are used for recreation and open space/wildlife habitat with seasonal public access and designated road accessibility. The Mount Haggin WMA offers seasonal public access for recreational use. Two roads (Mill Creek and a WMA road) offer vehicle access into the Mount Haggin WMA. However, vehicles are restricted from all other secondary roads.

A fractured bedrock groundwater aquifer containing arsenic underlies the majority of RDU 15. Remediation of the aquifer was deemed technically impracticable by the EPA, due to the high levels of contamination. Based upon this determination the EPA issued an arsenic Technical Impracticability (TI) waiver for Mill Creek. However, it was determined that contaminants from the bedrock aquifer were being transferred to Mill Creek and are the primary source of contamination to the creek. Originating in the Pintlar Mountain Range, Mill Creek joins Willow Creek within Deer Lodge County before eventually entering Warm Springs Creek.

Primary remedial concerns pertain to soil and water contamination resulting from smelter fallout from the Washoe Smelter. Remedial designs include the reduction of arsenic concentrations to levels below 1,000 ppm (parts per million) as well as the establishment of a diverse, effective, and permanent vegetation cover.

These land reclamation technologies meet storm water Best Management Practices (BMP) and were designed to reduce erosion and sediment transport, thus preventing further contamination of waters within RDU 15 Mount Haggin Uplands. Engineered storm water controls were drafted in the spring of 2005.

Institutional Controls (IC) were established to maintain the long-term integrity of remedial actions and prevent future exposure to contaminated soils. The IC program addresses land use restrictions and zoning, ground water controls, and public notices. For more information about the IC program visit the Superfund page of the Anaconda-Deer Lodge County website.

Visit the Superfund Library, located on the Arrowhead Foundation’s website, to review documents and research regarding the Anaconda Smelter NPL site. Additional information can also be found on the EPA’s website.