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ENVIRONMENTAL SCIENCE & ENGINEERING, INC <br /> MARTINEZ, CALIFORNIA <br /> DRILLING AND SAMPLING PROCEDURES �a <br /> Yu/ SLS <br /> ;7lI <br /> Drilling Procedures - Hollow Stem Auger Rig i C�JC)eT <br /> The borings are drilled with a minimum outside diameter 7 1/4 inch Hollow-stem auger. <br /> The auger flights are steam cleaned prior to their arrival on site and after each use. <br /> During drilling a retractable plug prevents soil from entering the central shaft of the auger <br /> flight. Undisturbed soil samples shall be recovered from the borings without introducing <br /> liquid into the borings. <br /> Soil Sampling Procedures <br /> Relatively undisturbed soil samples shall be collected from the borings for chemical analysis <br /> and visual description. When the target depth is reached a Modified California Sampler, <br /> consisting of an outer sampler barrel lined with two 6-inch long rings (OD 2.5 inch) placed <br /> end to end, is used to collect the soil samples. The Modified California Sampler and brass <br /> rings are cleaned prior to each assembly. The equipment is washed with tri-sodium <br /> phosphate solution, rinsed in tap water and allowed to air dry. The sampler is attached to <br /> the drive hammer, lowered through the hollow-stem auger, and driven 12 inches into <br /> undistrubed soil ahead of the auger. The sampler is then retrieved and the rings removed. <br /> The soil in the lower six-inch ring of the sampler is used for laboratory analysis. <br /> Immediately after the rings are retrieved, the lower ring is sealed with a teflon lined end <br /> cap and secured with tape. The sample is then labeled and placed in an ice chest for cold <br /> transport under proper chain of custody to a state certified chemical laboratory for analyses. <br /> The soil in the upper six-inch ring is used for lithologic description <br />