Laserfiche WebLink
CC&V Gold Mng . ID : APR 30 '96 20 :30 N0 .030 P .05 <br /> April 29, 1996 -2- 943-2847.003 <br /> inches by 14 inches in plan and 3 inches in depth. Tests conducted at a normal stress of <br /> 300 psi used a smaller upper shear box, which measured 6 inches by 6 inches in plan and 3 <br /> inches in depth. <br /> Interface shear strength testing, presented in Attachment C, was performed on the Cresson <br /> Ore Drain Cover Fill / 80 mil textured LLDPE geomembrane (textured face down) / clay <br /> area Soil Liner Fill. Test results yielded a peak cohesion of 2020 psf and friction angle of <br /> 17 degrees, and a residual cohesion of 2055 psf and friction angle of 16 degrees. The <br /> failure plane was noted to occur between the Soil Liner Fill and the 80 mil textured <br /> LLDPE geomembrane. These values exceed the minimum strength criteria required for <br /> the Phase II Pad, as originally identified in a January 9, 1996 letter from Golder to CC&V <br /> entitled "Interface Shear Strength Test Results for Phase H Cresson Project". <br /> The results of the liner load test also performed on the Cresson Ore Drain Cover Fill / 80 <br /> mil textured LLDPE geomembrane (textured face down) / clay area Soil Liner Fill <br /> configuration is presented in Attachment D. The configuration was subjected to a normal. <br /> load of 385 psi for 24 hours. No punctures or defects were observed in the geomembrane <br /> sample. <br /> The Cation Exchange Capacity (CEC) potential for a sample of clay area material was <br /> determined to be 11.8 meq/100 grams. The results area presented in Attachment E, and <br /> this value is in the range common for Kaolinite or Chlorite rich clays. Expansive clays <br /> (smectite) have potential CEC values in the range of 100 to 250 meq/100 grams (Lambe <br /> and Whitman, Soil Mechanics. John Wiley & Sons, 1969). Based on the low exchange <br /> potential, Golder expects the Soil Liner Fill material to be stable with respect to Cation <br /> exchange potential. <br /> Therefore, based on the results of the material specific permeability and interlace shear <br /> strength testing, Golder recommends that the clay area material is suitable for use as Soil <br /> Liner Fill provided that the material meets the following gradation specification, which has <br /> been incorporated into the specifications and is presented in Attachment F: <br /> U.S. Standard Percent <br /> Sieve Size Passing <br /> 2 inch 100 <br /> 314 inch 75-100 <br /> 3/8 inch 70-100 <br /> No. 4 55-100 <br /> No. 40 40-70 <br /> No. 200 30-60 <br /> Plasticity Index 15 (minimum) <br /> Golder Associates <br />