2008-04-15_REVISION - M1980244 (325)

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Main project area hydrologic conditions ~ 3 Groundwater levels in ESPMW-1 vary from 26.0 to 196.1 feet below ground level (bgl), although the wide range is due to some observations when the well was purged before water levels were measured; water level measurements reflecting the true elevation of the local water table range from 26.0 to 52.3 bgl. Groundwater levels in CRMW-3A and CRMW-3B vary from 10.3 to 35 feet bgl and 3.6 to 31.7 feet bgl, respectively. The modest fluctuations are seasonal and correlate with snowmelt, infiltration, and recharge processes to the alluvium and shallow bedrock. The groundwater types in CRMW-3A and CRMW-36 are characterized as calcium- sulfate water. The groundwater type in ESPMW-1 is characterized as calcium- bicarbonate water. Figure 3.3 is a piper plot showing the major ion water chemistry for the Arequa Gulch groundwater monitoring wells. The average pH of groundwater in alluvium (CRMW-3A) is 6.2 su, and the average pH of groundwater in the bedrock (CRMW-36) is 6.8 su. The average pH in ESPMW-1 is 7.9 su. Nitrate values average 9.4 mg/L in CRMW-3A and 2.9 mg/L in CRMW-3B. The nitrate values in ESPMW-1 are nearly all (29 of 32 analyses) less than the detection limit of 0.05 mg/L. Sulfate values average 740 mg/L in CRMW-3A and 726 mg/L in CRMW-3B. The average sulfate in ESPMW-1 is 40.4 mg/L. 3.6 Wilson Creek Current Conditions The Wilson Creek drainage and the MLE permit boundary are shown on Figure 3.1. Wilson Creek has two branches: Bateman Creek which begins west of the city of Victor and flows south, and the North Fork of Wilson Creek (also known as Theresa Creek) which begins north of the Town of Goldfield and flows south to southwest. After the confluence of these two branches, approximately 1.7 miles southwest of the city of Victor, Wilson Creek flows southwest and south to its confluence with Fourmile Creek, approximately six miles southwest of the city of Victor. The portion of the North Fork of Wilson Creek (Theresa Creek) at and above the Town of Goldfield is within the diatreme boundary. The remainder of the Wilson Creek drainage lies outside the diatreme (Figure 3.1). Historical mine features and other facilities within the Wilson Creek drainage include: the city of Victor Landfill, the Milsap Tailings, the Independence Tails, the City of Victor POTW, and stormwater from the City of Victor. Both historical tailing features were reclaimed and seeded in 2007. The Cresson Project disturbance near the Wilson Creek consists of the VLF, the ADR and associated surface facilities. The proposed MLE project. does expand the size of the VLF facilities near the Wilson Creek drainage. The limits of these mine components are shown on Figure 1.2. No new additional disturbance in the Wilson Creek drainage is proposed as part of the MLE project. • 2736 Cripple Creek & Victor Gold Mining Company Water Management Consultants