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<br /> <br /> <br />• Review of Reference 12 and our experience (References 1 <br />through 8) indicated the selected properties are within typical <br />ranges for coal waste. We believe the values chosen for analysis <br />reflect a conservative strength estimate. <br />The coal waste is relatively permeable, with laboratory <br /> <br /> <br />~CS falling head test results indicating permeabilities of 8 x 10'' <br />~~~ <br />/ cm/sec and 4 x 10"' cm/sec for compacted unprocessed and processed waste <br />res ectivel Fi s. B-12 and B-13 . The ranular nature of the waste and <br />P Y ( 9 ) 9 <br />resulting permeability should result in a fill material which settles relatively <br />quickly under imposed loads. The coal waste permeability should allow water <br />to pass through the material quickly and significantly reduce the possibility <br />• of developing a consistent saturated zone within the pile. Disposal of fines <br />(if required) should be carefully planned to avoid creating continuous layers <br />of lower permeability materials. <br /> <br /> <br /> <br /> <br />Native CIaV. Samples of the medium stiff to stiff clay were tested for <br />unconfined strength and in a consolidated-undrained (CU) triaxial test with <br />pore pressure measurements. The results of the CU test are presented on <br />Fig. B-14. Consolidated-drained (CD) effective stress parameters were <br />considered conservative values for long-term stability with values of ~ = 25 <br />degrees and cohesion = 380 psf determined from the laboratory testing. For <br />earthquake analysis the total stress condition is more appropriate. The total <br />stress strength from the CU test was estimated to be ~ = 15 degrees and <br />cohesion = 750 psf {Fig. B-14). This strength is an estimate for the saturated <br />• and consolidated sample from TH-3 in the lower portion of the valley. The <br />11 <br /> <br />