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07 October 2002 <br /> AGE-NC Project No 01-0827 <br /> Page 5 of 7 <br /> 41 SOIL SAMPLING <br /> Proposed monitoring well boring will be completed using a CME-75 truck-mounted,hollow stem drill <br /> rig equipped with 8 25-inch diameter hollow-stem augers Relatively undisturbed soil samples will <br /> be collected ahead of the drill bit at five-foot intervals beginning at five feet bsg in each of the borings <br /> using a California modified split-spoon sampler fitted with 2-inch diameter,6-inch long brass sleeves <br /> Upon 1 emoval from the sampler, the exposed ends of a selected sleeve will be covered with Teflon <br /> sheets, capped and sealed with tape Soil sample duplicates will be visually classified by an AGE <br /> geologist in accordance with the Unified Soil Classification System (USCS) Additionally, soil <br /> samples will be field-screened fol the presence of volatile organic compounds using an OVM <br /> Following sample collection, each pi eserved sample sleeve will be labeled with the boring location, <br /> depth, time, date and sampler's initials Appropi lately sealed and labeled samples will be placed in a <br /> chilled container undcr ice and transported under chain-of-custody to a DHS-certified laboratory fol <br /> analysis <br /> 4 2 MONITORING WELL INSTALLATION <br /> Following completion of dnlling of the monitoiing well boring, a 2-inch diameter Schedule 40 PVC <br /> 0 020-inch slotted well screen and casing will be installed A 5-foot section of well screen will be <br /> installed in the boring fi om a depth of 65 feet to 70 feet bsg <br /> The well casing, filtei pack and sealing materials will be placed into the borehole through the interior <br /> of the hollow-stem augers After installing the well casing, filter pack material consisting of <br /> pre-washed#3 Lonestai sand will be added from the bottom of the borehole to appy oximately one <br /> foot above the screened interval Following placement of the filter pack, the well will be surged to € <br /> assist in settling the filter pack Additional sand will be added if settling occurs <br /> G <br /> :r, L" i <br /> A nominal two-foot thick oi, for the depth discrete well, a four-foot thick bentonite seal will be <br /> placed above the filter pack to minimize grout penetration into the screened section of the well The <br /> bentonite seal will be formed by pouring bentonite chips (or pellets) into the annular space between <br /> the auger and the well casing and allowing them to settle on the tlltei pack Bentonite chips will be <br /> hydrated using five gallons of water The bentonite chips will be allowed to hydi ate for a minimum <br /> of one-half hour pnoi to grouting <br /> The remaining annular space above the bentonite seal will be filled to within one foot of the gi ound <br /> sur face with a cement grout The gi out mixture will consist of Type 7III portland neat cement and not <br /> more than 6 gallons of water per 94-pound sack of cement The grout will be placed by pumping <br /> through tremie pipe The EHD will be notified for gi out inspection at least 48 hours prior to <br /> conducting gi outing procedul es A typical monitoring well diagram is illustrated on Figure 3 <br /> Adt anted CJe0Envirwmcntal,ln� <br />