12142018Fri
Last updateWed, 12 Dec 2018 12pm

Local Regional News

Anaconda Stack

The third Remedial Design Unit (RDU) of the Anaconda Regional Water, Waste & Soils (ARWW&S) Operable Unit (OU),

RDU 3 – Smelter Hill Uplands addresses the area surrounding the Anaconda Reduction Works facilities located southeast of Anaconda.  Remediation addressed elevated levels of contaminants of concern in soils and waters; however, the EPA identified areas of RDU 3 where remediation was not practically feasible.  As a result, the Smelter Hill High Arsenic Area (HAA) was established.

Smelter Hill High Arsenic Area addresses the area surrounding the Anaconda Reduction Works facilities located southeast of Anaconda. There is mixed land uses within the 3,354 acres that make up RDU 3. Due to its size, RDU 3 was divided into three work areas based primarily on land ownership. RDU 3 is more significantly impacted by smelter fallout than many other areas within the Anaconda Smelter NPL site. It was determined that remediating surface soils, to comply with state and national standards, was impracticable within areas of RDU 3, such as Smelter Hill Uplands.  In 2011, an amendment to the original Record of Decision (ROD) for this operable unit was made. This amendment incorporated Smelter Hill Uplands into the Smelter Hill High Arsenic Area (HAA), which allows for higher arsenic concentrations in surface soil as well as ground and surface waters. Atlantic Richfield Company and Anaconda-Deer Lodge County own the properties included in the Smelter Hill High Arsenic Area. Land use and development restrictions were instated to minimize human and wildlife exposure to contaminants of concern.

In 2013, remedial designs for Smelter Hill Uplands was completed. These designs required the reduction of surface soil arsenic levels to current open space/recreation standards – where practicable – through the installation of protective vegetative covers. This process includes tilling with lime and soil amendments; leading to the ultimate establishment of a self-sustaining, diverse plant species. By 2017, engineering covers were installed in Smelter Hill Facilities. In the most contaminated areas, 18 inches of soil cover was installed. These covers are designed to support permanent vegetative cover of perennial grasses. In areas of less severe contamination, an 18-inch plant growth media was created. This particular media is made up of sugar beet lime, fertilizer, and organic matter. In the final areas, a six-inch layer of soil was installed. This soil provides assurance that the vegetative cover will be permanent and self-sustaining. In 2018, remediation continues with construction of storm water conveyance channels and further development into maintenance systems.

With remediation being at this point, bus tours will be available for this years Smeltermen’s Day Celebration. Bus tours will be held August 9th-11th at various times throughout the day. Spots are limited. Make your reservation at, discoveranaconda.com/events/smeltermans-week.

Resources:

Remedial Design Unit RDU 3 Smelter Hill Uplands Draft Final Design Report FDR/ Remedial Action Work Plan RAWP – July 2013

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