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Mr. Mark Campbell September 27, 2004 Page 2 ~~ CIVIL RES'JURCES, LLC • Ground Engineering (12 borings in Sasaki property in September 2000 and 9 borings around the perimeter of the Watada property in May, 2003), • CTLIThompson (10 borings in the Villano property in September, 2003), • Lafarge (4 borings in the Yokooji property, 3 borings in the Watada property, and 4 borings in Villano properly in February, 2004), • Civil Resources (7 geotechnical borings completed with piezometers across all properties in June, 2004), • Lafarge, down-hole hammer borings to investigate the extent of resources on all properties within the proposed pennitted site. September, 2004. • Civil Resources (28 geotechnical borings completed with one pumping well and 2 piezometers across all properties in September, 2004). The investigations by Ground, CTL, and Lafarge primarily focused on overburden soils and sand and gravel estimates. The previous two investigations by Civil Resources, obtained insitu claystone bedrock samples in order to obtain geotechnical index and engineering properties and were surveyed. The claystone bedrock samples were sent to Advanced Terra Testing for moisture content and density (ASTM D22t6 & D 2937), Atterberg limits (ASTM D4318), and percent fines (ASTM D1140). Additional insitu bedrock samples were obtained for future strength testing (TXCU~ ASTM D4767 and TXUU ASTM D2850). The locations of all borings are shown on Figure 2. Summary logs for the Civil Resources drilling investigation are shown on Figure 3. A summary of the bedrock index properties is included on Table 1. Laboratory test results are included in Appendix A. The suficial geology at the site was also mapped as part of Civil Resource's studies. Geologic mapping and exploratory drilling at the site identified three major natural geologic strata. These strata consist of two soil units and one bedrock unit. The units that were identified are as follows: 1) overburden silty sands, 2) alluvial sand and gravel, and 3) claystone bedrock. These units are described more completely as follows: Overburden Silty Sand: The overburden silty sand is an eolian (wind deposited) soil and occurs near surface across the entire site as a thin layer, of approximately 5 feet thick. The silty sand is generally loose to medium dense, dry to moist, light brown, with sand and fines (silt and clay), and is generally non-plastic. Sand and Gravel: The sand and gravel is present everywhere on the site overlying the bedrock. The sand and gravel is an alluvial deposit that ranges in thickness from approximately 30 feet to 50 feet, averaging approximately 40 feet. This deposit ranges from gravelly sand to sandy gravel and is generally medium dense to very dense. The sands are relatively clean with fines content (silt and clay) generally less than 10 percent. Lenses of clay (°mud lenses") and fine sand were encountered in some of the borings mostly along the southern portions of the site. The bulk ofthe on-site alluvial sand and gravel will be excavated, processed, and sold as aggregate products. ClaVStone: Bedrock was encountered across the site at depths ranging from approximately 35 feet to 55 feet. The bedrock surface is faidy irregular across the site, ranging in elevation from about 4,880 feet in the southwest to 4,910 feet on the northeast comer of the site. claystone is the main bedrock facies that was encountered undedying the alluvial sand and gravel. The claystone is locally silty and sandy with minor lignite zones. The claystone is generally very hard, moderately to highly plastic, moist to very moist, and is probably part of the Denver/Arapahoe Formations. The claystone has an average in-situ dry density and moisture content of 118 pcf and 15 percent, respectively. The claystone has average liquid limit and plasticity indices of 50 and 34, respectively. A summary of geotechnical data for the claystone bedrock is included in Table 1.