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Geotechnical Data Report Bruce Park Dam <br />Bowie Resources, Limited <br />April 2001 <br />Section 7 -Subsurface Conditions <br />7.1 Main Dam <br />Generalized subsurface conditions identified in the five borings drilled in the main <br />embankment aze discussed in the following paragraphs and also presented graphically on the <br />centerline profile and cross section shown in Figure 4. In general, the Main Dam <br />embankment and foundation consist of four material types identified as new embankment, <br />old embankment, foundation soils and bedrock. <br />7.1.1 New Embankment Materials <br />New embankment materials were encountered in Borings BD-101, BD-102 and BD- <br />105. These materials are appazently associated with the last embankment raise <br />completed in 1952. These materials are generally low to high plasticity clays with <br />varying amounts of sand. They are visually classified as CL and CH materials <br />according to the Unified Soil Classification System (USCS). These materials are <br />described as medium stiff to very stiff, dry to moist, brown, yellow-brown, green- <br />brown, dazk brown, gray and mottled gray in color. <br />The measured in-place dry densities of the New Embankment materials ranged from <br />100 pcf to 101 pcf These in-place densities are 97 percent of the maximum Proctor <br />dry density. The measured in-place natural moisture contents ranged from 23.7 to <br />24.6 percent. The in-place moisture contents of the New Embankment materials are <br />3.4 to 4.3 percent above the optimum Proctor moisture content. The laboratory <br />testing results also indicate these materials aze over-consolidated and have very low <br />permeability. <br />7.1.2 Old Embankment Materials <br />Old embankment materials were encountered in Boring BD-10~ and possibly in the <br />top 5 feet of Boring BD-103. These materials aze apparently associated with the <br />original embankment construction completed in the 1940s. They are sepazated and <br />distinguished from the New Embankment materials based on a sharp color change <br />identified in Boring BD-10~ at a depth of 29 feet. The Old Embankment materials <br />are generally ]ow to medium plasticity clays with varying amounts of sand. They are <br />visually classified as CL materials according to the Unified Soil Classification <br />GEI Consultants, h1C. 16 9929<=~-?-t6 GxofeCnnital paU Report <br />