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04 February 2000 <br /> AGE-NC Project No. 95-0167 <br /> Page 6 of 8 <br /> 4.2.2. Monitoring Well Installation <br /> The monitoring well boring will be completed using hollow-stem auger drilling techniques. Soil <br /> borings will be advanced using a truck-mounted drill rig equipped with hollow-stem augers . <br /> The pilot boring for ground water monitoring wells will be advanced utilizing 8 .25-inch augers. <br /> Proposed monitoring well design is illustrated in Figure 3 . <br /> Following completion of the soil borings for monitoring wells a 2-inch diameter Schedule 40 PVC <br /> 0.02-inch slotted well screen and casing will be installed. A 15400t section of well screen will be <br /> installed from a depth of approximately 15 feet to 30 feet bsg. <br /> The casing, filter pack and well sealing materials will be placed into the borehole through the interior <br /> of the hollow-stem augers. <br /> After installing the well casing, filter pack material consisting of pre-washed #3 Lonestar sand will <br /> be added from the bottom of the borehole to approximately two feet above the lower screened <br /> interval. Following placement of the filter pack, the well will be surged to assist in settling the filter <br /> pack. Additional sand will be added if settling occurs. A nominal one-foot bentonite seal will be <br /> placed above the filter pack. Bentonite chips will be hydrated be hydrated using five gallons of <br /> potable water. <br /> The remaining annular spaces will be filled to the ground surface with a cement grout. The grout <br /> mixture will consist of Type I/H portland neat cement and not more than 10 gallons of water per <br /> 94-pound sack of cement. The grout will be placed by pumping through the drill augers or tremmie <br /> pipe. Grouting procedures will be inspected by PHS-EHD personnel. A traffic-rated well box will <br /> be installed over the wells, in accordance with County regulations. <br /> Following completion of the monitoring wells, well elevations and locations will be surveyed by <br /> AGE personnel, relative to monitoring well MW- 1 . <br /> 4.3 , 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 /> 4.3 . 1 . Static Water Level Measurements <br /> Before sampling and during quarterly ground water monitoring, static water level and free-product <br /> thickness will be measured using an electric oil/water level indicator. Water level data will be <br /> I <br />