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i <br />' Appendix B <br /> EXPLORATORY BORING AND <br /> WELL INSTALLATION PROCEDURES <br />' The general procedures used in site assessments for drilling exploratory <br /> borings, collecting samples, and installing monitoring wells are described <br />' in this appendix. These general procedures are used to provide consistent <br /> and reproducible results; however, conditions may exist where variations <br /> of these procedures are applicable. The following procedures are super- <br /> vised by a California State-registered geologist. <br /> Exploratory Soil Borings <br /> Exploratory soil borings for sites characterized by relatively shallow (less <br /> than 100 fleet deep) ground water are generally drilled using 8- to 12-inch- <br /> diameter, continuous-flight, hollow-stem auger drilling equipment. The <br /> drilling method for sites in which depth to ground water is greater than <br /> 100 feet is determined on a case-by-case basis. Soil samples for logging <br /> will be obtained from auger-return materials and by advancing a modified <br /> California split-spoon sampler equipped with brass or stainless steel liners <br /> 1 into undisturbed soil beyond the tip of the auger. Soils will be logged by an <br /> EMCON Associates geologist according to the Unified Soil Classification <br /> System and standard geological techniques. Exploratory soil borings not <br />' used for monitoring well installation will be backfilled to the surface with a <br /> bentonite-cement slurry pumped into the boring through a tremie pipe. <br />' The soil sampling equipment will be cleaned with a detergent water solu- <br /> tion, rinsed with clean water, and equipped with clean finers between <br /> sampling intervals. Augers and samplers will be steam cleaned between <br /> each boring to reduce the possibility of cross contamination. Steam <br /> cleaning effluent will be contained in 55-gallon drums and temporarily <br /> 1 Rev. 0 <br /> pjflf921f920201 a B - June 1 1992 <br /> , <br />