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May 2005 -9- 053-2386 <br />0 5.3 Test #3 - Phase IV PSSA Liner System <br />The 100-mil smooth LLDPE geomembrane liner did not show any signs of failure or puncture. After <br />visual inspection, the liner material was vacuum tested for pinhole leaks resulting from the loading. <br />A vacuum pressure of 70 mm Hg was applied. The liner passed the vacuum tests, indicating the <br />absence of pinholes in the liner. <br />This liner load test demonstrate that minimum thickness 100-mil LLDPE smooth geomembrane liner <br />can withstand ore loads to an equivalent height of approximately 880 feet (670 psi, assuming an ore <br />density of 110 pcf), without puncture. This liner system is representative of the Pregnant Solution <br />Storage Area (PSSA) liner system which was approved and constructed within Phase IV of the <br />Cresson VLF. <br />5.4 Test #4 - Phases I and II OSA Liner System <br />The 80-mil textured VLDPE geomembrane liner had minor surface irregularities and indentations, but <br />did not show any signs of failure or puncture. After visual inspection, the liner material was vacuum <br />tested for pinhole leaks resulting from the loading. A vacuum pressure of 70 mm Hg was applied. <br />The liner passed the vacuum tests, indicating the absence of pinholes in the liner. <br />This liner load test demonstrate that minimum thickness 80-mil VLDPE textured geomembrane liner <br />can withstand ore loads to an equivalent height of approximately 880 feet (670 psi, assuming an ore <br />density of 110 pcf), without puncture. This liner system is representative of the Ore Storage Area <br />(OSA) liner system which was approved and constructed within Phases I and II of the Cresson VLF. <br />5.5 Conclusions <br />The results of the liner load tests indicate that the Phases I, II, III, and IV OSA liner systems and the <br />Phase IV PSSA liner system can maintain hydraulic containment under equivalent ore depths greater <br />than the designed and approved ore depth of 590 feet. Additional liner load testing was not <br />conducted to evaluate the Phase I and H PSSA liner systems because geometrical constraints would <br />prevent the stacking of ore in these areas to greater than the designed and approved ore depth of <br />approximately 590 feet. <br />E <br />t?nrs aa.aaoo.rar?ao? Golder Associates