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was logged by a geotechnical engineer, and representative samples of subsurface materials <br />encountered were brought back to our laboratory for detailed examination and testing. Borehole <br />logs from the site investigation aze presented in Appendix B. <br />Each borehole was surveyed. Borehole locations are summarized in Table I and are presented <br />on Drawing No. 2 in Appendix A. <br />Table 1. Summary of Borehole Locations <br />Borehole Elevation <br />ID Northing Easting (ft) Location <br />BG06-08 19199.4730 36576.6660 6107.9 Gob Pile No. 4 <br />BG06-09 19244.2250 36741.2740 6107.0 <br />BG06-10 19231.6200 37811.7910 6061.5 <br />BG06-11 19446.6620 37689.8980 6100.0 Gob Pile No. 2 <br />BG06-12 19451.7140 37888.4930 6085.8 <br />3.1.1 Gob Pile No. 4 <br />As previously indicated, boreholes BG06-08 and BG06-09 were drilled on a bench excavated <br />into the native soils for the Gob Pile No. 4 footprint. The contractor indicated that the surface <br />elevation of the boreholes was approximately 10 vertical feet above the fmal proposed subgrade <br />for the gob pile foundation. As indicated on Drawing 2 in Appendix A, the boreholes are located <br />neaz the toe of the proposed Gob Pile No. 4. Borehole BG06-08 was located on the western end <br />of the bench, while borehole BG06-09 was located on the eastern end of the bench. <br />Native soils on this slope consist of colluvium and slope wash materials originating from <br />sedimentary units on the slope above. Soils encountered during drilling at the Gob Pile No. 4 <br />foundation generally consisted of dry to damp, hard, moderate brown clayey gravel, cobbles, and <br />boulders. By nature, colluviaUslope wash soils such as these are heterogeneous. Accordingly, <br />the fines content and the rock content varied somewhat both laterally and vertically. <br />The boreholes were advanced to total depths of 37 and 57 feet. Each borehole was temtinated <br />due to significant deflection of the augers by lazge boulders at depth. No bedrock or <br />groundwater was encountered in either borehole. SPT "N-values" ranged from 34 blows per foot <br />to 50 blows for zero inches, indicating hard soil consistency and cobble boulder content. <br />Recovered samples were also noted to be hard, consistent with the blow counts. <br />3.1.2 Gob Pile No. 2 <br />Boreholes BG06-10, BG06-11, and BG06-12 were drilled within gob at Gob Pile No. 2. The <br />boreholes were drilled primarily to obtain thin-walled (Shelby) tube samples, therefore few <br />standard penetration tests were conducted. In general, gob consisted of moist, very stiff, clayey <br />gravel to gravelly clay with variable sand, cobble and boulder content. The boreholes were <br />advanced to depths of 41.5 to 46.5 feet. No foundation soils or bedrock was encountered in any <br />of the boreholes. No groundwater was encountered during or immediately after drilling, <br />Bowie Gob Pile No. A stability report <br />Project #OS-126-GEO <br />Page 7 of IS <br />