develop a remedial investigation and feasibility study 

 workplan for the site. The RI/FS will address the charac- 

 terization and cleanup of soils, surface water, and ground 

 water contamination. At present, contamination of ground 

 water and the potential threat to Silver Bow Creek is the 

 most serious concern. The Emergency Response Branch prepared 

 an Engineering Evaluation and Cost Analysis (EE/CA) document 

 to address cleanup and treatment of contaminated ground 

 water. This information may be incorporated into the RI/FS, 

 as the Emergency Response Branch will not be conducting 

 further work at the site. 



Anaconda Smelter 



Copper ores were processed at the Anaconda Smelter site 

 at various times between 1884 and 1980. When operations 

 ceased in 1980, approximately 6,000 acres of waste materials 

 were left behind. The area was designated a Superfund site 

 in early 1983. In the fall of 1984, the Anaconda Minerals 

 Company, as the potentially responsible party, entered into 

 an agreement with EPA to conduct several site remedial 

 investigations . 



In the first stage of the RIs, a variety of sites and 

 media were studied. Four focused investigations included the 

 slag piles, the arbiter plant, flue dust, and beryllium 

 disposal areas. For the master investigation, the Old Works, 

 ground water, surface water, soils, tailings, alluvium, 

 hydrogeology, and geochemistry were studied. 



The RI reports submitted by the Anaconda Minerals 

 Company are still under review by EPA. During the course of 

 the soils investigation, levels of arsenic and other heavy 

 metals of concern to human health were found in the community 

 of Mill Creek, located immediately adjacent to the Anaconda 

 Smelter site. A study conducted by the Centers for Disease 

 Control (CDC) revealed elevated levels of urinary arsenic in 

 seven of ten Mill Creek children. As a result, the Anaconda 

 Minerals Company entered into an agreement with EPA in July 

 1986 to conduct a separate expedited remedial investigation 

 of the Mill Creek area. In May 1986, EPA began to 

 temporarily relocate families with small children and others 

 at high risk, while a permanent solution to the contamination 

 problems was developed. These families never returned to 

 Mill Creek and, along with many others, sold their properties 

 to the Anaconda Minerals Company. 



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