including slag piles, flue dust piles, tailings, and the 

 Anaconda and Opportunity tailings pond systems that cover 

 nearly 4,000 acres, were left behind. In 1983, the Anaconda 

 Smelter site was placed on the EPA's National Priority List, 

 and Superfund remedial investigations began in late 1984. 

 These activities are ongoing and are addressed in more 

 detail in Chapter 3 . 



In Butte, milling and smelting activities continued 

 until about 1910, by which time the Anaconda Copper Mining 

 Co. had purchased and shut down all the major concentrators 

 and smelters in the area except the Pittsmont Smelter (which 

 operated until 1930) (MultiTech 1987a) . Thereafter, nearly 

 all the ore was shipped to Anaconda for milling and process- 

 ing, and Butte became known mainly as a mining center (Tetra 

 Tech 1986a) . The numerous underground mines in the Butte 

 area (estimates range from about 50 to over 4 00) were either 

 closed down or purchased by the Anaconda Copper Mining Co. 

 (which became the Anaconda Company in 1955) between 1917 and 

 the mid 1970s. The company started the Berkeley open-pit 

 copper mine in 1955, and it built the Weed Concentrator in 

 1964 to mill and concentrate ore from the Berkeley Pit and 

 the underground mines still operating in the area. These 

 concentrates were then shipped to Anaconda for smelting. 

 The company shut down all underground operations in 1976, and 

 production at the Berkeley Pit ceased in 1982. The company 

 (renamed the Anaconda Minerals Company [AMC] in 1977) , ceased 

 operations entirely in 1983 when the East Berkeley Extension 

 Pit was closed. Some of the company's Butte properties were 

 purchased by Montana Resources, Inc. (MRI) , in 1985, and MRI 

 resumed mining and milling in 1986 (MultiTech 1987a) . 



In 1983, the EPA placed Silver Bow Creek and contiguous 

 portions of the upper Clark Fork on the National Priorities 

 List as a high-priority Superfund site. Remedial investiga- 

 tion studies for the site were initiated in late 1984 and are 

 ongoing. In 1986, the Silver Bow Creek Superfund site 

 boundary was officially extended to include the city of Butte 

 and the stretch of river between the Warm Springs Ponds and 

 Milltown Dam. Superfund activities in the basin are 

 discussed in more detail in Chapter 3. 



FORESTRY 



The mines and smelters at Butte, Anaconda, and Philips- 

 burg, and the Northern Pacific Railroad created a large 

 demand for lumber. In the upper Clark Fork region, much of 

 the activity took place on the Blackfoot River, where logs 

 were floated down to sawmills on the Clark Fork. By the 

 late 1880s, the timber stands closest to the mills were 

 depleted, and logging operations were extended farther 



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