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2-14 <br />SC) with minor layers of low plasticity, sandy, silt or clay (USCS ML or <br />CL). <br />A series of three consolidated undrained (CU) triaxial shear tests were <br />performed on undisturbed samples of the dam fill from Boring G-3. The <br />test results are shown in Figure 7. These tests indicate an effective <br />friction angle of 29 degrees and effective cohesion of 655 pounds per <br />square foot. Suitable undisturbed samples ,of the alluvial soils could <br />not'be obtained for strength testing. The general coarse nature of the <br />material indicates that the strength is relatively high. <br />0 <br />Pinhole dispersivity tests were conducted on three samples (G-3, 72-74 <br />feet; G-5, 84-85 feet; and G-5, 104-105.5 feet) of fill and alluvium, <br />with distilled water and tailings solution obtained from the lower <br />tailings pond. The fill and alluvium samples were found to be nondis- <br />persive, (Sherard et al., 1976) in both solutions. <br />The grain size distribution tests on the soils in the dam indicate <br />percentages of fines (-No. 200 sieve) ranging from 20 to 80 percent. <br />Atterberg limit tests indicate low plasticity fines, mostly silts with <br />some clays. Using correlations between percentage and type of fines and <br />permeability, the;,;permeability.of the core is expected to be in the <br />range between 10., -and 10 cm/sec with the higher value indicative of <br />soils with lower percentage of fines'. The rising head tests in the <br />piezometers indicate a permeability in the range of 10-4 to 10-5 cm/sec <br />for the fill in total. The field tests therefore indicate permeability <br />values within the upper end of anticipated values from the empirical <br />relationships. Mechanisms other than primary or interstitial flow may <br />be contributing to the permeability of the soils such as small cracks or <br />other discontinuities. <br />