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• will be secured, using a safety harness, to an immobile object <br /> (island canopy support or bumper of the service truck) similarly <br /> to the drilling safety methods. The hand auger/sampled boring <br /> will be drilled at an angle that will prevent the dri_la3r from <br /> leaning ou:. over the excavation. This angle will ba measured wi4h <br /> a brunton to correct the angled hole to vertical depth. <br /> To economically determine the vertical extent of petroleum <br /> contamination associated with the product lines, a 4" diAm ter <br /> hand auger with sampler and driver will be utilized. see Figure 8. <br /> The holes will be hand auclered in five foot intervals, the auger <br /> then will be w$thdrawn and a sampler contcaininq one 2"x6'* sterile <br /> brass sleeve will be placed at the base of the hole and hand <br /> given to obtain a sleeved sample for certified laboratory <br /> analysis. This pr#acedure will be accomplished from outside the <br /> excavation as out lined above. <br /> The sampling of the borings within the product line trenches will <br /> commence at the 10 foot depth and samples will be obtained in 5 <br /> foot intervals until screening with the FID indicates that the <br /> soil is clean. <br /> The sample borings produced in the product line trenches will be <br /> backfilled with neat cement by pouring from the surface. The <br /> exploratory borings produced by Rugate Drilling showed that the <br /> soil has enough clay and silt for the holes to stay open. <br /> Tne sample borings produce in the excavation will b+ part of the <br /> over excavation process and will be left open, not be backfilled, <br /> see Appendix F. <br /> After the vertical and lateral extents of contamination have been <br /> documented by the hanI angered/sampled borings, we will evaluate <br /> the need to deepen the excavation (overexeavate) using an <br /> excavator or eavonets Versadrill for the removal of contaminated <br /> soil. if the placement of vapor/ground water extraction wells <br /> within the excavation is viable the Versadrill will be used. The <br /> Vereadrill is a crane operated solid flight auger, that is capable <br /> of extending out into an excavation and augering a 360 diameter <br /> hole in 3 foot intervals. Sampling of the Versadrilled hole is <br /> C performed by lowering a hand sampler/driver that contains one 20 x <br /> 6" sterile brass sleeve and driving into the undisturbed soil <br /> after the versadrill has been removed. The sampling will occur in <br /> 5 foot intervals starting at the 20 foot depth from surface (5 <br /> feet below :he excavation surface) to the SS foot depth. , see <br /> Figure 8 and Appendix G. <br /> All samples wil3 be obtained by a qualified geologist working <br /> directly under the supervision of California Registered Goologi$t <br /> #3037. The samples will be collected, preserved, labeled and <br /> chain of custody hand delivered to ChemTech Analytical <br /> Laborstor;es, 3017 Kilgore Road #110, Rancho Cordova, CA 95742 <br /> (916-535-3962) . ChemTech is a State of California certified lab <br /> (#359) . All soil samples obtained from borings and/or excavations <br /> 35 <br />