2012-02-28_REVISION - M1980244 (65)

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Cripple Creek & Victor Gold Mining Company Squaw Gulch Valley Leach Facility Design 4.12 Appurtenant Structures Access roads have been incorporated into the design where possible to provide for small truck traffic access around the perimeter of the VLF and construction roads within the VLF area. A 15 to 20- foot -wide road (typical) in addition to 6 feet for a safety berm and 6 feet for a small drainage ditch has been incorporated into the design. The access roads were designed for small vehicular traffic only. In addition, an 80 -foot- wide haul truck ramp from the LOB to the Squaw Gulch VLF PSSA has been included in the design. Layouts of the access roads and LOB location are presented in Drawings A205 and A210 for Phases 1 and 2, respectively. 4.13 Highway 67 Realignment and Crib Wall Construction As part of the Squaw Gulch VLF construction, existing State Highway 67 will require realignment and an existing historic crib wall will require removal, as demonstrated in Drawing A20. The highway will be realigned to cross the PSSA embankment, as discussed previously and as shown on Drawing A207. Other drawings associated with the Highway 67 realignment will be provided separately. A portion of the timbers from the crib wall removal will be maintained for use in construction of a new retaining wall adjacent to the realigned Highway 67, to allowing viewing by the general public. The proposed location for the new retaining wall is shown in Drawing A207, with wall details on Drawing A800. 4.14 Reclamation /Closure At closure, the VLF will be detoxified via rinsing (all areas of the VLF are available for rinsing). After detoxification, the VLF side slopes will be regraded to overall 2.5H:1V slopes. The reclaimed VLF configuration is shown on Drawing A600. The VLF design also includes a closure underdrain. The purpose of the closure underdrain is to provide a means to drain accumulated precipitation water from the VLF at and during the post closure period (after the ore heap has been rinsed), to prevent overtopping of the PSSA embankment. The closure underdrain consists of the following components: • A blanket drain that is located beneath the PSSA sump (i.e., low point); • A thicker (i.e., 3 -foot) layer of SLF underlying the lower geomembrane within the portion of the PSSA which overlies the closure drain; and • A passive drain consisting of five (5) drilled shafts extending a minimum of 10 feet into the diatreme zone. During the post closure period, the blanket drain beneath the PSSA will be penetrated and used to convey accumulated water within the PSSA to the primary sump (see Drawings A300 and A360 and Figure 3). The blanket drain consists of a minimum 3- Project No.: 74201125G0 Page 25 1 September 2011 amec'3