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' y „ Additionally, it was shown that the presence of the Mosquito Fault provides a hydraulic barrier to lateral flow of ground water flow in the bedrock. • The direction of ground water flow is coincident with the surface water drainages, where ground water discharges into streams and creeks. The Climax Mine Storm Water Management Plan (W.W. Wheeler, 1995) details potential discharges from mines, seeps, and springs in the affected area of ground water. The following sections present a discussion on the hydrogeologic conditions which are specific to the three drainages at the Climax mine site. Tenmile Creek valley Ground water in the Tenmile Creek valley primarily occurs in a veneer of alluvium and glacial till which overlay bedrock consisting of Paleozoic sedimentary and Tertiary quartz monzonite formations. Data from seismic refraction surveys and monitoring well logs (Climax Molybdenum Co., 1984) indicate that the alluvium and glacial till range in thickness from 0 to over 90 feet. The alluvium consists of deposits ranging in size from clays and silts to boulders. Ground water level data indicate that ground water occurs between 10 and 30 feet below ground surface with a seasonal flux in elevation. The direction of ground water flow in the Tenmile Creek valley is controlled by the bedrock topography and outcroppings. Hydraulic conductivity data of the bedrock and the overlaying soils are summarized in Table 1. These data were measured as part of the construction of the Mayflower Tailings Dam. A total of 44 tests in eight holes were conducted using both slug and packer testing methods (Kumar&Assoc., 1994). • Table 1 Summary of Field Hydraulic Conductivity Tests Unit Hydraulic Conductivity Range (ft/yr) Alluvium 2,595 - 88,378 Glacial Till 22 - 1,238 Paleozoic Sedimentary Bedrock 0 - 596 Tertiary Quartz Monzonite Bedrock 18 - 54 As shown, the field hydraulic conductivity test data indicate that the alluvium and glacial till in the Tenmile drainage are significantly more permeable than the bedrock units. By comparison, the bedrock units are of relatively low permeability. Therefore, the bedrock units are not capable of transporting significant quantities of ground water. In 1987, two ground water monitoring wells, GWM #1 and GWM#2 were installed in the • Tenmile drainage, downgradient of the Mayflower Tailings Dam. Drillers' and completion logs