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NewFields <br />Perspective. Vision. Solutions. <br />TECHNICAL MEMORANDUM <br />9400 Station Street <br />Suite 300 <br />Lone Tree, CO 80124 <br />T: 720.508.3300 <br />F: 720.508.3339 <br />To: Cripple Creek and Victor Gold Mining Company <br />From: Jay Janney -Moore, P.E. <br />Reviewed By: Keith Williams, P.E. <br />Project: Liner Integrity Engineering Support <br />Project No: 475.0106.023 <br />Subject: VLF2 Geomembrane Recertification <br />Date: 10 April 2018 <br />NewFields is updating our recommendations to Cripple Creek and Victor Gold Mining Company <br />(CC&V) to determine the integrity of the geomembrane liner along the southern side of the <br />Squaw Gulch Valley Leach Facility (VLF2) between the 9860 -foot and 9650 -foot benches. <br />1.0 BACKGROUND <br />Previously, NewFields had recommending using a leak location survey to verify the integrity of <br />the geomembrane liner. This plan required exposing an isolating strip of geomembrane around <br />the perimeter of the survey area. Upon review, NewFields is concerned about the stability of the <br />material on the slope after exposure of the geomembrane long the toe of the area to be <br />surveyed. <br />2.0 RECOMMENDATIONS AND PATH FORWARD <br />To develop a revised plan to inspect the geomembrane liner, NewFields developed two figures <br />of the area of the ore shift. Figure 1 depicts the ore surface in December 2017, after the ore had <br />shifted. NewFields examined the contours to estimate the location of the slide. The area shown <br />with green hatching is of primary concern and the area with blue hatching is of secondary <br />concern. Figure 2 is based on a March 2018 survey which shows the ore slope after CC&V <br />removed a majority of the material and also shows the areas of primary and secondary concern. <br />NewFields is recommending the following steps be taken to inspect the geomembrane liner. <br />f As shown on Figure 2, two 4" High Volume Solution Collection (HVSC) pipes will have a utility <br />location survey complete. This will be completed by locating the upstream end of the pipes <br />and inserting a tracer wire down the pipe. This survey will verify the location pipes compared <br />to the as -built survey. <br />