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Addendum to Geotechnical Data Report Bowie Resources, Limited July 2002 Executive Summa The purpose of this Addendum Report is to present additional geotechnical information that was collected after the Geotechnical Data Report, Bruce Pazk Dam, Delta County, Colorado was issued in April 2001 (GEI, 2001). Analyses and interpretations of the information collected will be provided in a separate document. GEI performed the following scope of work for this project: a) developed and observed completion of a subsurface investigation program, which included soil and bedrock borings, field testing, and installation ofopen-standpipe piezometers and cable inclinometers; b) performed laboratory tests on selected soil samples collected during the subsurface investigations; and c) prepared this Addendum Geotechnical Data Report. Glacial materials were encountered initially or below topsoil in the borings drilled in the existing landslide area and extend to depths from 6.7 to 24.5 feet. The glacial materials are generally low to medium plastic clays with 15 to 75 percent sand, 5 to 30 percent gravel, and classify as CL according to the Unified Soil Classification System (USCS). A possible . failure zone less than I foot thick was identified in Boring BL-102 within the glacial deposits, at a depth of 2 9.5 feet. This material consists of soft, maist to very moist, low to medium plastic clays that visually classify as CL according to the USCS. Bedrock was encountered below the glacial materials. The bedrock generally consists of interbedded claystone and sandstone of the Mesa Verde Group. Groundwater was not encountered in any of the borings at the time of drilling below the landslide, drilling fluid was lost in BL-102 at about 19.5 feet in depth. In general, the main dam embankment and foundation consist of four material types identified as new embankment, old embankment, foundation soils, and bedrock as described in Geotechnical Data Report (GEI, 2001). In Boring BD-104, new embankment material was identified from ground surface to 8S feet, old embankment materials from 8.5 feet to 12 feet, foundation soils (glacial deposits) from 12 feet to 18.5 feet, and bedrock from 18.5 feet to 23.5 feet. A few small roots and other organic material were identified in the old embankment material. However, an organic layer was not identified. . Groundwater was not encountered in Boring BD-104 during drilling, GEI Consultants, Inc. iii 9929202-0]-03 ACtlentlum Geolecnnmal Data Rpt