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<br />be approximately 28 degrees and the cohesion intercept <br />approximately 250 psf. <br />1 <br />The NAVFAC (1982) correlations indicate that the silty <br />and gravelly sands, which predominate below the upper 5 to 10 <br />ft of the heap leach site, are capable of developing internal <br />' effective stress friction angles ranging from 27 to 40 degrees. <br />For analytical purposes, an average friction angle of 33 <br />degrees and a cohesion intercept of zero has been assumed for <br />t these materials. <br />Laboratory testing was conducted to determine the <br />friction angle for the heap leach material. Laboratory test <br />results showed a friction angle of 35 degrees. A conservative <br />value of 30 degrees has been used for the stability analyses. <br />1 The cohesion intercept for the heap leach material has been <br />assumed to be zero. <br />I Section D.7.5 discusses the relation of the engineering <br />properties to the stability analyses for the heap leach. <br />' D.7.3.2 Geochemical Characteristics <br />The geochemical testing program for the heap leach ore <br />consists of the following test series: <br />1. Acidification/neutralization potentials; <br />2. Leachability; <br />3. EP Toxicity; and <br />4. Humidity cell testing. <br /> Two heap leach ore samples were tested. The first sample <br />1 consisted of s pent heap leach ore, which was subjected to a <br /> fresh water rinse intended to simulate proposed heap <br /> detoxification procedures. The second sample consisted of the <br /> same spent and rinsed heap leach ore subjected :o a second <br /> <br /> D-42 <br /> <br />