1995-10-02_REVISION - M1977493 (7)

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TITANEnvironmentai By PJA Date 1/22/96 Subject: Calculate g.w. flux at Mayflower Page / of 3 Chkd By • Date ' Tailings: Ratio to Tenmile Cr. discharge Proj No 4104 -001 Purpose: A) To calculate the ground water flux from the Mayflower tailings area to Tenmile Creek at the Climax Mine site. B) To calculate the ratio of stream water to ground water discharge. Methodology: A) The ground water flux (discharge) through the area (Figures 1, 2) was calculated using the equation: Q = - KA(dh/dl) (Freeze and Cherry, 1979) where: Q is discharge K is hydraulic conductivity A is the cross - sectional area through which flux is calculated dh is the change in hydraulic head across the flux dl is the distance between the hydraulic head measurements. B) The ratio of stream water to ground water discharge was calculated by dividing the stream discharge by the ground water discharge (calculated in part A). Part A: Hydraulic Conductivity. K: Hydraulic conductivities of the Tenmile alluvium deposits are based on field permeability tests conducted near Mayflower Tailings Pond (data included in appendix). The geometric mean of the hydraulic conductivities taken in the alluvial/ glacial material is 903 ft/yr (calculation in appendix). K = (903 ft/yr)x(yr/ 365d)x(d/ 86400s) K = 2.9 x 10 -5 ft/s K = (2.9 x 10 ft/s) x (30.48 cm /ft) = 8.7 x 10 cm /s According to the table of hydraulic conductivities of different materials (Freeze and Cherry, 1979) this hydraulic conductivity reported by Climax is in the upper range for glacial materials. The relatively higher hydraulic conductivity is likely due to the influence of alluvial deposits with the glacial material at this site. Flux Area (A): The cross - sectional area through which the ground water flux was calculated is shown on Figure 1. This cross - section was chosen because ground water flow at this location is confined in the vertical direction by an impermeable, igneous intrusion known as the Humbug Stock (Figure 3). The horizontal extent of ground water flow is confined by the bedrock outcrop on the west side of Tenmile Creek and the 10,440 ft. surface elevation contour on the east side. Width of the cross section (w), measured from A to A 1000 ft.