2014-02-07_REPORT - M1980244 (7)

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Cripple Creek & Victor Gold Mining Company Mill Site Earthworks Project Final Report Quality Assurance Monitoring & Test Results January 31, 2014 ameO Ames began placing SLF for the Mill Site Earthworks Project September 2012 and completed placement November 2012. SLF was compacted to a minimum thickness of 12 inches by a smooth drum vibratory compactor. AMEC observed SLF depth verification tests performed by Ames to confirm appropriate fill depth. Areas where the SLF thickness was found to be non - compliant with Project Specifications were re- worked and re- tested until the area was compliant. The SLF depth verification is discussed further in Section 4.2.5. The minimum SLF density was 95 percent of the maximum dry density at -2 percent to +3 percent of optimum moisture content as determined by Standard Proctor tests performed by AMEC. Areas of the SLF that failed to meet the moisture density requirement were re- moisture conditioned, re- compacted, and re- tested to until passing results were achieved. Prior to geomembrane deployment on the SLF, Ames compacted, proof rolled, and hand worked the fill surface to be free of desiccation cracks and abrupt grade changes; AMEC then inspected the surface. Sharp or angular stones greater than 0.75 inches in diameter were removed from the finished surface. AMEC and Lone Star both provided formal subgrade approval prior to geomembrane deployment. Subgrade acceptance forms are presented in Appendix G. 2.6 Mill Site Earthworks Composite Liner System The Mill Site Earthworks liner system is comprised of a composite liner, as follows: • The composite liner system consists of a minimum of 12 inches of compacted SLF overlain by a layer of 80 -mil single -sided or double -sided textured Linear Low Density Polyethylene ( LLDPE) geomembrane (textured side down). Double -sided textured LLDPE geomembrane was used where the slope exceeded 2.5H:1 V (horizontal:vertical). • Drain Cover Fill (minimum of 2 feet). The installation of the geomembrane layer for the Project began October 2012 and was completed November 2012. Lone Star installed approximately 1,517,215 square feet (neat line) of 80 -mil single -sided and double -sided textured LLDPE geomembrane to the Project Specifications. Geomembrane installation for the Project is discussed further in Section 3.3. Ames anchored geomembrane at the geomembrane limits in an anchor trench measuring 3 feet deep by 2 foot wide. Ames backfilled the anchor trenches with suitable anchor trench backfill material or with SLF material where the future geomembrane liner covers the anchor trench. Ames placed anchor trench backfill in maximum 12 -inch- thick compacted lifts. Anchor trench backfill was compacted with a hand operated 500 pound vibratory compactor and "Jumping Jack" compactors to Project Specifications. Rol