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Addendum to Geotechnical Oata Repoli <br />Bowie Resources, Limited <br />Juiy 2002 <br />2.2 Exploration Borings <br />Four exploratory borings (BL-101, BL-101A, BL-102, and BL-102A) were drilled at selected <br />locations in an existing landslide area and one exploratory boring (BD-104) was drilled in the <br />right side of the upstream slope of the main dam. The borings were located in the field based <br />on interpretation of topographic features identified on the base topographic map provided by <br />Bowie Resources. The objectives of the exploration borings were to: 1) identify the depth of <br />the likely failure zone in the landslide and obtain representative samples of the material in the <br />failure zone for laboratory testing; and 2) identify if organic material is present in the right <br />side of the of the upstream slope of the main dam. <br />A sixth boring was planned to be drilled within the landslide area on the right (northwest) <br />shore of the reservoir between the access road and normal pool elevation. This boring was <br />not drilled due to time restrictions imposed by the U.S. Forest Service. <br />2.2.1 Drilling Methods <br />All borings were drilled by Heliport Drilling with attack-mounted Simco model #4000-TR2 <br />rig. The borings were advanced through the landslide and main dam soils and weathered <br />bedrock using a HQ size casing advancer. Water was used as the drilling fluid. "Disturbed" <br />sampling methods included driving a ] -318-inch I.D. split-spoon sampler ahead of the casing, <br />and collecting continuous core using a 3-inch I.D. continuous sampler inside the casing. <br />"Undisturbed" samples were collected by pushing a 2-inch I.D. thin wall (Sharon) tube ahead <br />ofthe casing. <br />Except where piezometers and inclinometers were installed, the remaining Borings (BL-101 <br />and BD-104) were backfilled to the ground surface with Portland cement upon completion of <br />drilling and testing. <br />2.2.2 Logging Procedures <br />GEI's field engineer prepazed field logs for each boring. Boring BL-102A was drilled solely <br />for the purpose of installation of an inclinometer and is about 10 feet from Boring BL-102. <br />Boring BL-120A was not logged because of the proximity to Boring BL-102. Soil and <br />bedrock samples were visually classified and logged to identify subsurface stratigraphy, to <br />observe features important in evaluating soil and rock mass properties, and locating the likely <br />failure zone in the landslide. Soil classifications, moisture, stiffness, density, particle sizes <br />and other descriptions were recorded for soil samples. For rock core, the rock type, <br />lithologic descriptors, weathering, fracturing, sample recovery as a percentage of the sample <br />interval, rock quality designation (RQD), coring time, drilling observations, and other <br />descriptions during drilling were recorded. The rock and soil classification system used <br />GEI COIISUItanIS, IriC. 4 9925202-07-03 aEdenCOm Geo~ecMi~i Data R-~ <br />