2014-02-07_REPORT - M1980244 (7)

Home Browse Search

Cripple Creek & Victor Gold Mining Company Mill Site Earthworks Project Final Report Quality Assurance Monitoring & Test Results January 31, 2014 6.5 Defect and Repair Observations ameO AMEC inspected geomembrane panels for damage that may have occurred during manufacture, transport, deployment, or installation as discussed in Section 6.1. Damage noted (during or after deployment) by AMEC was reported. AMEC observed all panels and seams for defects until Ames covered the geomembrane with DCF. AMEC documented defects by assigning and marking on the geomembrane a unique defect identification code. The summaries of defects and repairs, including the approximate locations of each repair, are presented in Appendix J.4. 6.6 Destructive Testing AMEC selected destructive test locations based on Lone Star's completion of welding for the geomembrane, various working conditions, and on seaming observations (e.g., suspicion of a defective weld). Lone Star obtained and tested 177 fusion seam destructive samples and 19 extrusion seam destructive samples Lone Star constructed approximately 78,338 lineal feet of fusion welded seams and 3,253 lineal feet of extrusion welded seams for the geomembrane. The specified frequency of destructive testing was one test per 500 lineal feet of weld. AMEC identified, and Lone Star obtained, destructive samples from the panel seams at a frequency of one destructive test sample per 442 lineal feet of fusion welded seam, and one per 171 lineal feet of extrusion welded seam. The test frequencies exceeded project requirements. The summaries of destructive test results for fusion seams are presented in Appendix J.S. Record Drawing No. 4 of 4 presented in Appendix A and shows the destructive test sample locations. 6.7 Non - Destructive Testing Lone Star performed non - destructive seam testing on completed seams and geomembrane repairs. Non - destructive testing for seams included pressure testing fusion welded seams and vacuum testing extrusion - welded seams and repairs. AMEC monitored and documented the non - destructive testing. Prior to pressure testing fusion seams, Lone Star heat sealed both ends of the air channel between the two tracks of the double -wedge weld. A pressure gauge was inserted in one end of the sealed channel; the channel was pressurized to approximately 30 pounds per square inch (psi) using an air pump. After pressure stabilization, AMEC monitored the gauge for a minimum of 5 minutes. The maximum allowable pressure drop was 3 psi., with the gauge left in place, Lone Star cut the opposite end of the seam. If the gauge pressure dropped to zero, the seam was determined to be continuous. In cases where the seam was found to be discontinuous, the seam was subdivided into shorter sections until continuous seam 26