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1 <br /> <br /> <br />t <br /> <br /> <br /> <br />1 <br />t <br />1 <br /> <br /> <br />1 <br /> <br />1 <br />1 <br /> <br />1 <br />values for the other two material types cited in the Phase I <br />analysis are utilized again in the present analysis. The following <br />table summarizes material properties used in the present analyses: <br />MATERIAL PROPERTY SUMMARY <br />Material Zone Effective Effective Unit <br />Type Friction Cohesion Weight <br />Angle (') (psf) (pcf) <br />Refuse 1 32.12 204.5 99.47 <br />Alluvium 2 32.10 0.0 130.00 <br />Bedrock 3 38.00 1,000.0 150.00 <br />Pond 4 0.00 0.0 62.4 <br />SECTION MODELS: <br />The two section models consider the pile complete to a full <br />utilization elevation of 5025, according to topography provided by <br />Powderhorn Coal, Co. The pile/alluvium contact and the <br />alluvium/bedrock contact were both modelled according to <br />information presented in the Phase I analysis report. The various <br />piezometric surfaces, pore pressures and boundary conditions <br />modelled are discussed below. <br />Section A-A - As noted in the Piezometer Data Evaluation <br />section of this report, section A-A represents a cross section of <br />the pile near its southern end. The pore pressures affecting this <br />section are measured by the 200 and 400 series piezometers. The <br />evaluation of piezometric data for this section suggests that an <br />impervious or less pervious horizontal boundary exists at <br />elevation 4879.25. For the present model, pore pressures above <br />this suspected boundary are simulated by a single piezometric <br />surface which intercepts the face of the slope at the same <br />elevation as the boundary (elevation 4879.25), then slopes upward <br />to an elevation of 4901.02 at the horizontal location of piezometer <br />402. The piezometric level then slopes upward at an angle of 12- <br />degrees from elevation 4901.02 to intercept the top of the pile at <br />elevation 4944.68. The 12-degree slope was based on the slope of <br />a similar phreatic surface above a presumed boundary along section <br />C-C as discussed in following paragraphs. The 12-degree angle <br />determined for section C-C was based on a line between known water <br />surface levels in the 100 and 300 series piezometers. Pore <br />pressures in the refuse material between the boundary and the pile <br />foundation contact are simulated by applying a constant pore <br />pressure equal to the maximum individual value measured from <br />piezometers measuring this zone. This value was taken from the <br />piezometer evaluation data as 5-feet of piezometric head or 312 <br />PSF. Pore pressures in the alluvium foundation material are also <br />simulated by a constant pore pressure taken from the piezometer <br />26 <br />1 <br />