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• Acid -Base Accounting Tests (815 samples) <br />• Long -term accelerated weathering tests (42 humidity cell tests) <br />The 2011/2012 study updated the regional hydrology of the proposed MLE2 areas, including the <br />extended mining areas, overburden storage areas, and SGVLF area. The study refined the <br />evaluation of ground water flow and transport in Grassy Valley and the footprint of the <br />redesigned and extended ECOSA, by conducting the following: <br />• Permeability testing: Conducting 72 permeability tests on site materials in the area <br />• Water level monitoring: Continuously monitoring water levels in a total of 33 monitor <br />wells, including 15 nested well sets to monitor vertical hydraulic gradient at each location <br />• Water pressure monitoring: Installing a total of 13 multi -level vibrating wire pressure <br />transducers up to 750 feet deep, and continuously monitoring the water pressure and <br />vertical hydraulic gradient at each transducer <br />• Surface water monitoring: Installing three Parshall flumes in Grassy Valley, fitted with <br />transducers to continuously monitor flow of water in that drainage <br />• Ground water quality sampling: Sampling 80 monitor wells for metal and non -metal <br />species <br />• Surface water sampling: Opportunistic sampling of surface water in Grassy Valley and <br />Squaw, and Arequa Gulches on the infrequent periods of flow <br />Using all the hydrology and geochemical information developed for the District, an evaluation <br />was conducted of the fate and transport of water infiltrating to the subsurface through all mine <br />areas, mine backfill, and overburden storage areas proposed for MLE2. The results of the <br />analysis were verified by checking against the observed behavior of the hydraulics and chemistry <br />of the diatreme since surface mining began in 1993, using the measured vertical hydraulic <br />gradients in and near the diatreme, and the flow rate and chemistry of the regional ground water <br />table flowing at the Carlton Tunnel portal. <br />The conclusions of the evaluation of MLE2 geochemistry are as follows: <br />• There will be no ground water flow from MLE2 mine facilities to surface water within <br />the permit boundary <br />• There will be no mine area lakes that will develop at any time in the MLE2 mined areas <br />(or any other surface mined areas in the District) during active mining or after closure <br />• There will be no measurable impact to flow or saturation in any potential wetland or <br />other areas of Grassy Valley not disturbed by the proposed MLE2 project <br />Cripple Creek & Victor Gold Mining Company <br />Cresson Project Mine Life Extension 2 <br />4 -7 <br />