edge of the tailings, and construction of a drainage ditch 

 along the southern edge of the tailings (Hydrometrics 1983a) . 



The ultimate fate of the Colorado Tailings will be 

 determined by the Superfund program. The Colorado Tailings 

 and the Butte Reduction Works (adjacent to the Colorado 

 Tailings) constitute a separate operable unit that is being 

 evaluated by the state and EPA. This operable unit is a 

 fairly high priority, with Phase II activities scheduled to 

 be underway in first-quarter FY 89. If a removal alternative 

 were chosen, the tailings and the contaminated peat layer 

 beneath them would have to be addressed. 



Old Works 



As mentioned in the Superfund section, the Old Works 

 area (Figure 3-3) is the site of the first smelters in 

 Anaconda. Nine discrete waste deposits have been identified 

 in the vicinity of the Old Works. Waste types include 

 tailings, black slag, heap-roast slag, and red sands (mixed 

 slag and tailings) . Flue dust deposits are also found near 

 the flues of the Upper and Lower Works. Combined, these 

 wastes are estimated to cover about 326 acres (Tetra Tech 

 1987) . 



For the Stage I Remedial Investigation, Tetra Tech 

 (1987) collected grab samples, tailings cores, and trench 

 samples from these wastes. The ranges of selected metals 

 concentrations in the grab samples are provided in Table 3-7. 



The EPA considers the Old Works area to be a high- 

 priority operable unit due to its proximity to a housing 

 development and Warm Springs Creek. Work plan negotiations 

 are underway with the Anaconda Minerals Company, and work 

 will likely begin there this fall. 



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