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26 November 2001 <br /> AGE-NC Project No. 98-0492 <br /> Page 5 of 7 <br /> fitted with 2-inch diameter,6-in6h long'brass sleeves.Upon removal from the sampler,the.exposed <br /> ends of a selected'sleeve. will be.covered with Teflon sheets, capped and sealed with tape. Soil <br /> sample duplicates will be visually classified by an AG geologist in accordance with the Unified <br /> Soil Classification System(USCS).Additionally,.soil s pies will be field-screened for.the presence <br /> of volatile organic compounds using.an OVM. <br /> Following.sample collection,each preserved sample sle ve will be labeled with the boring location, <br /> depth,time, date and sampler's initials: Appropriately sealed and-labeled samples will be placed in <br /> a cliilled container under ice and transported under.chaff -of-custody to a DHS-certified laboratory. <br /> 4.2. MONITORING WELL INSTALLATION <br /> Following completion of drilling-of.,each pilot boning,' a 2-inch diameter Schedule 40 PVC <br /> 0.020-inch slotted well screen and casing will be installc d. A 20-foot section of well screen will be <br /> installed in each well,extending approxiftiately15 feet b low and 5 feet above the top of the ground <br /> water table. <br /> The well casing,filter pack and sealing materials will be laced into the borehole through the interior _ <br /> of the hollow-stem augers. After installing'the well asing, filter pack material -consisting of <br /> pre-washed#3112 Lonestar sand will be added from the b atom of the borehole to approximately two <br /> feet above the.screened interval. Following placementc f 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 /> A: nominal two-foot thick bentonite seal will be place -above the.filter pack to minimize grout <br /> penetration into the screened section of'the well. The bentonite seal will be formed by pouring . <br /> bentonite chips into the annular space between'the auge and the-well casing and allowing them to <br /> settle on the filter pack. Bentonite chips will be hydratec using five gallons of water. The bentonite <br /> chips will be allowed to hydrate for a minimum of-one-ialfhour prior to grouting. <br /> The remaining annular space'above the bentonite seal w 11-be filled to within.one foot of ground . <br /> surface with a cement grout..The grout mixture will consist-of Type I/II portland neat cement and <br /> not more than 6 gallons of water per 94-pound sack of cement. 'rhe grout will be placed by pumping <br /> through tremie pipe. The PHS-EHD will be notified for grout inspection at least 72 hours prior to <br /> conducting grouting procedures. �A typical monitoring ell diagram is illustrated on Figure:4. <br /> Following-completion of the monitoring wells,well elevations and locations will be surveyed by a <br /> California-licensed surveyor. <br /> Advanced GeoEavironmentaI,lnc.- <br />