2008-08-11_REVISION - M1980244 (3)

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amec?' August 11, 2008 Mr. Mark Vanoni Sr. Environmental Coordinator Cripple Creek & Victor Gold Mining Company Post Office Box 191 100 North Third Street Victor, Colorado 80860 Re: Phase 4 Drainage Enhancements Dear Mark: Project 8420119300 AMEC Earth & Environmental (AMEC) has prepared this letter report for the Cripple Creek & Victor Gold Mining Company (CC&V) providing recommendations and guidelines for enhancing the drainage conditions along the northern edge of the Phase 4C Valley Leach Facility (VLF). These enhancements are being recommended to improve solution recovery time in this area of the facility. Based on the site visit conducted on 22 July, the following drainage enhancements are recommended: • Adding extensions to the identified existing 4" Tertiary pipes to near the edge of the VLF to increase the influence area of the solution collection pipes ; • Installation of an additional 4" collection pipe along the northern edge of the VLF (at the toe of the ore heap) to augment the existing 6" collection pipe; • Excavation of shallow trenches along the internal access road to direct solution flow into the collection piping system; • Scarifying the surface of the DCF to improve flow into the solution collection piping network; and • Adding windrows along all new pipes that are installed and any existing pipes within the area to be scarified. A plan view of the 4" Tertiary pipe extensions is shown in Figure 1 and a typical section is shown in Figure 2. Prior to installation of the extension pipe, the surface of the DCF should be scarified along the alignment of the extension pipe, and a windrow formed upgradient of the pipe (see Figure 3). The depth of scarification should be approximately 4 to 8 inches. As shown, the extension pipe should be located within the scarified layer. This positioning reduces the need to AMEC Earth & Environmental, Inc. 304 Inverness Way South, Suite 490 Englewood, Colorado 80112 Tel: (303) 433-0262 Fax: (303) 433-0362 www.amec.com S:IPROJECTS11193 crAv gold mining phase 4 dmimp W - designlphase 4 dminape IOWA=