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Mr. Mark Campbell September 27, 2004 Page 4 ~~ CIVIL RES'JU RCES,LLC of the intersection of the circle with the ground surface. The Spencer method is preferred because it is able to satisfy both moment and force equilibrium, but can only analyze one surface at a time. Therefore, prior to submitting the final stability run, at least 1200 failure surfaces were analyzed to determine the lowest factor of safety. The five cross-section locations were selected to analyze stability for the mining limits under different surcharge loads and depth to bedrock conditions. The locations are described below and shown on Figure 2. - Section A-A': This section considers the northwest portion of the Villano property that will be mined near Highway 85. A surcharge of 300 psf was included to model the live load on Highway 85. - Section B-B': This section considers the oil well located on the Viltano property. A surcharge of 500 psf was included to model the dead load from the storage tank. - Section C-C': This section considers a deep bedrock section near Highway 85 on the western margin of the Sasaki property. A surcharge of 300 psf was included to model the live load from Highway 85. - Section D-D': This section considers a higher phreatic surface due to full Flow conditions in the Fulton Lateral and the live load from WCR 27. A surcharge of 250 psf was included to model the live load from WCR 27. - Section E-E': This section considers a cross section along the southern margin of the Yokooji property, along WCR 6. A 250 psf surcharge was included to model the live load from WCR 6. The material index and engineering strengths assumed in this slope stability report are discussed below. Final design geotechnical investigations will further refine our knowledge of the subsurface and embankment material properties. MATERIAL PROPERTIES Overburden The index properties for the insitu overburden were based on field testing data and on our engineering judgment; the following parameters have been used to model the overburden. Dry Unit Moist Unit Saturated Unit Cohesion C' psf Friction Angle 4y' ° Wei ht c Wei ht c Wei ht c 103 117 121 0 35 Alluvial Sand and Gravel The sand and gravel is generally medium grained sand, medium dense, goody to well graded, and generally clean. The deposit ranges from fine to coarse sand with some silt and occasional rounded to well rounded gravels less than 2- inches indiameter. The alluvial sand and gravel has been modeled as follows: Dry Unit Moist Unit Saturated Unit Cohesion C' psf Friction Angle 4ti'° Wei ht c Wei ht c Wei ht c 119 129 129 0 38