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J ~~ <br />SMITH WILLIAMS CONSULTANTS, INC. <br />• <br />5.1.2 Input Parameters <br />5.1.2.1 Conceptual Model <br />A representative conceptual model, incorporating the areal distribution and engineering <br />properties of the foundation materials that underlie the site, was developed from the results of <br />field investigations to enable modeling of soil profile characteristics representative of those at the <br />site. The critical stability cross sections analyzed are shown on Drawings A700 through A720. <br />The following material profile was used in the models: <br />^ Crushed Ore: Crushed ore that is placed in the VLF is totally underlain by the <br />composite liner. The ore slope within the Phase 5 VLF will vary, depending on <br />location. In the area upgradient of the Phase 5 VLF PSSA embankment, the ore will <br />be placed at the angle of repose with bench offsets to provide an overall slope of <br />2.OH:1 V. In areas with downsloping foundations, the ore will be placed at the angle <br />of repose with bench offsets to provide an overall slope of 2.SH:1 V. In all other <br />areas, the slope of each lift of ore will be at the angle of repose with bench offsets to <br />provide an overall slope of the ore at 1.6H:1 V during operations. <br />^ Composite Liner: The composite liner will be installed below the crushed ore and <br />consists of a 1-foot-thick SLF overlain by a geomembrane. <br />^ Foundation Material: Based on the results of the geotechnical investigations, the <br />VLF foundation material consists of a relatively high strength foundation material <br />representing the competent bedrock materials or granular native soils. <br />5.1.2.2 Geotechnical Material Design Parameters <br />The development of the conceptual stratigraphic model discussed above in Section 5.1.2.1 <br />provides a framework on which to base the geotechnical analyses. Material design properties <br />used in the stability analyses are discussed below and summarized on Drawings A700 through <br />A720. <br />Crushed Ore. For the stability analysis, the crushed ore material was modeled with an angle of <br />internal friction of 40 degrees with no cohesion, based on testing performed on Cresson ore <br />.material. The results of the testing performed on nominal 1'/2-inch minus Cresson ore was <br />reported to the DRMS in a January 9, 1996, letter from CC&V titled, "Cresson Project: Permit <br />M-1980-244: Procedures and Materials for 1996 Construction. " The results. indicate a <br />curvilinear failure envelope with internal friction angles ranging between 45 degrees (under low <br />S:\PROJECTSN 125 CCBV PHASE 5 VLF\H2 - DESIGMAREQUA VLFlVLF PHASE 5 FINAL REPORT V2.DOC 30 <br />