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Cripple Creek & Victor Gold Mining Company <br />Squaw Gulch VLF Phase 1 <br />(9,550-foot Elevation Bench to Geomembrane Panel P1635) <br />Final Report <br />Quality Assurance Monitoring & Test Results <br />January 2016 <br />Project No.: 74201125N0 Page 28 <br />6.6 Non-Destructive Testing <br />ECA performed non-destructive seam testing on completed seams and geomembrane <br />repairs. Non-destructive testing for seams included pressure testing of fusion-welded <br />seams and vacuum testing of extrusion-welded seams and repairs. Amec Foster <br />Wheeler monitored and documented the non-destructive testing. <br />Prior to pressure testing fusion seams, ECA heat sealed both ends of the air channel <br />between the two tracks of the double-wedge weld. A pressure gauge was inserted in <br />one end of the sealed channel; the channel was pressurized to approximately 30 pounds <br />per square inch (psi) using an air pump. After pressure stabilization, Amec Foster <br />Wheeler Personnel monitored the gauge for a minimum of 5 minutes. The maximum <br />allowable pressure drop was 3 psi over a 5 minute period. After the 5 minute period was <br />completed, ECA cut the opposite end of the seam with the gauge left in place. If the <br />gauge pressure dropped to zero, the seam was determined to be continuous. In cases <br />where the seam was found to be discontinuous (evident by no pressure drop at gauge <br />upon cutting the opposite end of the seam), the seam was subdivided into shorter <br />sections until continuous seam sections were located and passing pressure tests were <br />performed. Failed portions of seams were capped. <br />If a pressure test failed, ECA checked the seam section for leakage, and repaired and <br />re-tested the seam or capped it. If ECA was unable to find the leak, the seam was divided <br />into two sections, each section being tested to locate the area of concern. This <br />subdivision process was repeated until the leak location was identified. If the leak area <br />was not located, ECA capped the seam and vacuum tested the repair. <br />ECA tested extrusion welded seam sections and repairs with a vacuum box. Prior to <br />vacuum box testing, a soap and water solution was applied to the seam section. The <br />vacuum box was placed over the seam area and energized with a pump capable of <br />creating a vacuum of not less than 5 psi. ECA and Amec Foster Wheeler observed the <br />action of the vacuum on the seam for a minimum of 10 seconds. Each consecutively <br />tested seam length was overlapped a minimum of 3 inches. If soap bubbles appeared, <br />Amec Foster Wheeler marked and documented the leak location. ECA repaired the leak <br />and vacuum tested the repair. This procedure was also followed to test extrusion welds <br />associated with repairs and patches. <br />The seam non-destructive test summaries (fusion pressure tests) are presented in <br />Appendix J.6. Extrusion seam vacuum test verification is presented in the Extrusion <br />Welding Summary in Appendix J.3. <br />Amec Foster Wheeler personnel conducted a final walk through and inspection of the <br />installed geomembrane surface and completed acceptance forms to verify completion <br />of all repairs of the geomembrane liner prior to DCF placement. The geomembrane liner <br />acceptance notifications are presented in Appendix J.7.