In July 1985, Schafer (1985) took this analysis a step 

 further by addressing lands that had reduced yields — a more 

 subtle vegetative productivity effect. Based on photo inter- 

 pretation and very limited field reconnaissance, he estimated 

 that there were approximately 28,000 acres of irrigated or 

 previously irrigated land affected in some way by tailings 

 contamination in Deer Lodge, Silver Bow, Powell, Missoula, 

 and Granite counties. This total yield loss would be 

 equivalent to 12,475 acres at full production (Schafer 1985). 



It is not clear whether mitigation of irrigation- 

 affected lands will be addressed within the confines of the 

 Super fund program. A variety of techniques, including soil 

 treatment, water treatment, and crop management, could be 

 employed to treat these lands (MultiTech and Stiller and 

 Associates 1984) . \ 



Floodplain Mine Wastes 



Between the late 1880s and the mid-1950s, mining and 

 smelting wastes were discharged directly into Silver Bow 

 Creek and large quantities of tailings were transported 

 downstream to the Clark Fork. The Milltown Reservoir near 

 Missoula, which is the first major impoundment below the 

 Butte-Anaconda mining district, trapped substantial amounts 

 of mine wastes and contaminated sediment. However, a large 

 volume of river-borne mine wastes has been deposited across 

 the floodplain in the Deer Lodge Valley. The most severely 

 affected area is between Butte and Deer Lodge, although 

 floodplain mine wastes occur down to Missoula. These 

 deposits have had significant detrimental effects on the 

 Clark Fork riparian system, and they may be a source of 

 continued contamination (Johns and Moore 1985) . 



The first large floodplain deposit in the headwaters is 

 Ramsay Flats, located along Silver Bow Creek near Ramsay 

 (Figure 3-7) . This deposit covers approximately 160 acres 

 and consists of fluvially transported tailings mixed with 

 natural sediment (MultiTech 1986) . Its average depth is 

 estimated to be about six feet, and metal analyses conducted 

 in a study by Peckham (1979) indicated a range of 69-5,400 

 ppm copper, undetected-1, 900 ppm lead, and 460-5,500 ppm 

 zinc. 



For the tailings portion of the Silver Bow Creek 

 Remedial Investigation, 15 samples were collected between 

 Butte and the Warm Springs Ponds. Samples of soil buried by 

 tailings were also collected to determine if metals had 

 migrated out of the tailings. Results of the metal analyses 

 are summarized below (MultiTech 1987c) . 



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