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19 November 1999 <br /> AGE-NC Project No. 99-0604 <br /> Page 8 of 10 <br /> of the hollow-stem augers. After installing the well casing, filter pack material consisting of pre- <br /> washed 42/12 Lonestar sand will be added from the bottom of the borehole to approximately two <br /> feet 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 /> A nominal two-foot bentonite seal will be placed above the filter pack to minimize potential for <br /> grout 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 auger and the well casing and allowing them to <br /> settle on the filter pack. Bentonite chips will be hydrated using five gallons of water. The bentonite <br /> chips will be allowed to hydrate for a minimum of one-half hour prior to grouting. <br /> The remaining annular space above the bentonite seal will be filled to within 1 foot of the ground <br /> surface with a cement grout. The grout mixture will consist of type ILII 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 tremmie pipe. The PHS-EHD will be notified for grout inspection at Ieast 48 hours prior <br /> to conducting grouting procedures. <br /> Following completion of the monitoring wells, well elevations and locations will be surveyed by a <br /> California-licensed surveyor. <br /> 4.4. WELL DEVELOPMENT <br /> Development will consist of a combination of bailing to remove the major portion of fine-grained <br /> sediment from inside the well, surging to flush out or draw in sediment from the filter pack, and <br /> additional bailing to finish the removal of sediment. Development activities will be continued until <br /> field parameter (pH, electrical conductivity, and temperature) readings have stabilized. <br /> 4.5. GROUNDWATER SAMPLING PROCEDURES <br /> Groundwater sample collection will be performed in accordance with pertinent applicable sampling <br /> protocols, details of which are presented below. <br /> 4.5.1. Static Water Level Measurements <br /> Before sampling and during groundwater monitoring, static water level in the wells will be measured <br /> using an electric water level indicator. Water level data will be recorded to the nearest 0.01 foot from <br /> the surveyed reference point marked of the top of the PVC well casing. Before and after each use, <br /> Advanced GeoEnvironmenta[,Inc. <br />