2020-07-08_REVISION - M1980244 (20)

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Cripple Creek&Victor Gold Mining Company Squaw Gulch VLF Phase 2A Part 3 Record of Construction Report ■ 475.0106.032 July 2,2020 combination. A 24-inch long by 12-inch wide sample was cut from the seam centered on the seam lengthwise. The sample was then cut in two halves. One half was archived by the CQA Monitor to be tested later, if necessary. Ten 1-inch coupons were then cut from the remaining sample half. Five coupons were tested for shear strength and five coupons were tested for peel strength using a tensiometer. The different failure types and test codes for fusion and extrusion destructive testing are presented on Figures 3 and 4, respectively. All destructive testing was performed by Tetra Tech in the presence of the CQA Monitor. A total of thirty six fusion and thirteen extrusion welds were tested. Two fusion destructive tests failed within the Squaw Gulch Phase 2A Part 3 area and the extent of the failure was delineated by obtaining samples before and after the failed sample. Once the failing area was identified, that portion of the seam was capped. Fusion and Extrusion Destructive Testing Summaries are presented in Appendix J.5.1 and Appendix J.5.2, respectively, and the tensiometer certifications are presented in Appendix L. 3.4.6. Geomembrane Pressure Testing Pressure testing was performed to ensure all fusion welded seams had continuity throughout their entire length. The ends of the seam were sealed and the air channel in the seam was pressurized using a small air compressor to a minimum of 30 pounds per square inch (psi), for a minimum of five minutes. A pressure gauge and needle were used to monitor the air pressure in the seam. If the pressure dropped less than 3 psi, the opposite end of the seam from the pressure gauge was cut. If the needle dropped, continuity was confirmed throughout entire seam length and the test was considered "passing." If a pressure drop of more than 3 psi occurred or the continuity was not proven, smaller sections of the seam were tested to delineate the failing section of the seam. All failing seams or portions of seams were repaired, and vacuum tested.The Geomembrane Seam Pressure Testing Summary is presented in Appendix J.6. 3.4.7. Geomembrane Defects and Repairs The CQA Monitor constantly inspected the geomembrane for defects from the time it was deployed until it was covered with DCF. A defect is defined as any item in which a repair is necessary to create a continuously sealed geomembrane layer.All defects were marked with a defect number by the CQA Monitor. Repairs were performed using the extrusion welding method and patches extended at least 6 inches beyond the defect in all directions. All repairs were assigned a repair number and cross checked with defect numbers to ensure that all defects were repaired. All repairs and extrusion welded seams were non-destructively tested using a vacuum box. The area being tested was covered in soapy water and the vacuum box was sealed to the geomembrane. A vacuum was pulled over the area for at least 10 seconds and if P:\Projects\0106.032 VLF2 Phase 2 CQA\J-REPORTS\Cert Report-Phase 2A Part 3\475.0106.032 CCV PHASE 2A Part 3 ROC REPORT.docx Page 13