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12 September 2008 <br /> AGE-NC Project No. 98-0440 <br /> Page 4 of 6 <br /> undisturbed soil below the bit on the lead auger. <br /> Upon removal from the sampler,sample sleeves will be separated using a clean knife.Based on the <br /> amount of sample recovery, either of the leading sample sleeves will be preserved for possible <br /> laboratory analysis by covering the exposed ends of the sleeve with Teflon sheets,plastic end caps <br /> and sealed with tape. <br /> Following sample collection,each preserved sample sleeve and will be labeled with boring location, <br /> depth,time, date and sampler's initials.Appropriately sealed and labeled samples will be placed in <br /> a chilled container under ice and will be transported under chain-of-custody procedure to a California <br /> Department of Public Health(CDPH)-certified laboratory. <br /> Soil encountered in the borings will be visually classified by an AGE geologist or environmental <br /> specialist in accordance with the Unified Soil Classification System (USCS). Additionally, soil <br /> samples will be field-screened for the presence of volatile organic compounds using an organic vapor <br /> meter(OVM) equipped with a photo-ionization device (PID). <br /> Investigation-derived waste,including soil cuttings and decontamination rinseate,generated during <br /> drilling activities will be containerized in appropriately labeled DOT-approved 55-gallon drums and <br /> stored on-site pending disposal. Appropriate disposal alternatives will be determined based on <br /> laboratory results of soil and water analysis. <br /> 3.2. MONITORING WELL INSTALLATION <br /> Following drilling completion of the pilot borings, 2-inch diameter Schedule 40 PVC 0.020-inch <br /> slotted well screen and casing will be installed. A 10-foot section of well screen will be installed <br /> in the wells.Well casing,filter pack and sealing materials will be placed into each borehole through <br /> the interior of the hollow-stem augers.After installing the well casing,filter pack material consisting <br /> of pre-washed#2/t2 Lonestar sand will be added from the bottom of each borehole to approximately <br /> two feet above the screened interval.Following placement of the filter pack,each well will be surged <br /> to assist in settling the filter pack. Additional sand will be added if settling occurs. <br /> A nominal two-foot thick bentonite seal will be placed above the filter pack to minimize grout <br /> penetration into the screened section of the wells. The bentonite seal will be formed by pouring <br /> bentonite pellets into the annular space between the auger and the well casing and allowing them to <br /> settle on the filter pack. Bentonite pellets will be hydrated for a minimum of one-half hour prior to <br /> grouting using five gallons of water.Remaining annular space above the bentonite seal will be filled <br /> to within one foot of ground surface with cement grout. The grout mixture will consist of Type MI <br /> portland neat cement and not more than 6 gallons of water per 94-pound sack of cement. Grout will <br /> Advanced GeoEnvironmental,Inc. <br />