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presence of historic mine features in many of the drainages continue to influence the current <br />surface water quality. These features are notable in Squaw Gulch, Arequa Gulch, Wilson Creek, <br />and Grassy Valley. Sulfate concentrations in the surface waters of Arequa Gulch below the <br />AGVLF have increased since 2003. The increase in sulfate concentrations appears related to the <br />oxidation of spent materials under the AGVLF liner coupled with reduced infiltration and a <br />declining water table. <br />Ground water data (levels and water quality) have been updated through 2011. Ground water <br />levels have remained relatively constant in the district since 2008. Seasonal water level <br />fluctuations due to the infiltration of snowmelt and precipitation are observed in the shallower <br />monitor wells, piezometers, and boreholes. A dominant control on the ground water resources is <br />the strong vertical gradient and drainage of the Diatreme in the District. This drainage has <br />created widespread dry conditions in at least the upper 750 feet of the diatreme and the adjacent <br />granites in portions of Grassy Valley. The drainage also is widespread in Poverty Gulch, Squaw <br />Gulch, and Vindicator Valley due to the occurrence of Diatreme in these drainages. Water <br />quality conditions have remained generally stable across the District for the monitoring record, <br />except for the monitor locations noted in Arequa Gulch and Bateman Creek. The presence of <br />historic mine features in many of the drainages continue to influence the current ground water <br />quality. These features are notable in Squaw Gulch, Arequa Gulch, Wilson Creek, and Grassy <br />Valley. The Arequa Gulch monitor wells (CRMW -3A and CRMW -3B) and WCMW -2 in <br />Bateman Creek show increased in concentrations in sulfate. The increase in sulfate <br />concentrations appears related to the oxidation of spent materials under the AGVLF liner due to <br />reduced infiltration and a declining water table. <br />MLE2 impacts to Grassy Valley are evaluated in detail in the reports titled "Cresson Project <br />Hydrogeochemical Evaluation" and "Cresson Project East Cresson Overburden Storage Area <br />Evaluation" both dated February 2012 and prepared by ABC. The WHEX and ECOSA will be <br />developed in the upper and middle reaches of Grassy Valley, respectively. The progressive <br />development of WHEX will capture an increasing portion of the precipitation (snow and rain) in <br />the upper reaches of Grassy Valley. The development will reduce runoff and alluvium ground <br />water contributions to the Grassy Valley surface waters. At the final disturbance limits of <br />WHEX, the naturally low seasonal runoff at GV -01 is likely to be reduced further due to the <br />partial loss of the upgradient stream drainage. Flows at GV -01 (or just below GV -01) may <br />persist due to storm water management on the east margin of WHEX. Seasonal flows at the <br />downstream surface stations GV -02 and GV -03 also are likely to be slightly decreased due to the <br />development of WHEX. <br />'Cripple Creek & Victor Gold Mining Company <br />Cresson Project Hydrologic Evaluation for Mine Life Extension 2 <br />40 <br />