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24 June 2008 <br /> AGE-NC Project No. 05-1286 <br /> Page 2 of 7 <br /> 3.1. WELL INSTALLATION <br /> From 21 through 26 April 2008, pilot borings were advanced on-site for the installation of <br /> groundwater extraction wells EW-11B and EW-1213,groundwater injection wells IW-BHI and IW- <br /> BH2A and groundwater monitoring well MW-1313. The well locations are shown on Figure 2. <br /> 3.1.1. Drilling <br /> Pilot borings for groundwater extraction wells EW-11B and EW-12B were advanced to 88 and 89 <br /> feet, groundwater injection wells IW-BH1 and IW-BH2A to 80 and 85 feet, and groundwater <br /> monitoring well MW-13B to 81 feet below surface grade (bsg), respectively. This effort was <br /> accomplished utilizing a CME-85 equipped with both 8.25-inch and 12.25-inch hollow stem augers. <br /> The drill rig and the three-man crew were supplied by Cascade Drilling, Inc. of Rancho Cordova, <br /> California. <br /> Pilot boring EW-12B was advanced with 12.25-inch augers on 21 April 2008, to 60 feet bsg and, <br /> with permission from EHD, was secured at the surface until well construction materials were <br /> delivered on 25 April 2008.On 24 April 2008,pilot boring EW-12B was further advanced to 80 feet <br /> bsg with 8.25-inch augers to collect continuous core soil samples and,with permission from EHD, <br /> secured at the surface until 25 April 2008. On 25 April 2008, pilot boring EW-12B was advanced <br /> with 12.25-inch augers from 60 ft bsg to the total depth of 89 feet bsg. <br /> Pilot boring EW-11B was advanced with 8.25-inch augers on 24 April 2008, to 80 feet bsg; <br /> continuous core samples were collected from 60 to 80 feet bsg. With permission from EHD, the <br /> 8.25-inch augers were completely removed and the borehole secured while awaiting well <br /> construction materials. On 26 April 2008,pilot boring EW-11B was advanced to total depth of 88 <br /> feet bsg with 12.25-inch augers. <br /> Pilot boring IW-BH 1 was advanced to 80 feet bsg on 22 April 2008 with 12.25-inch augers. On 23 <br /> April 2008,pilot boring IW-BH2A was initially advanced to 80 feet bsg,but due to heaving sands <br /> that restricted full insertion of the well casing,was re-advanced to 85 feet bsg after removal of the <br /> well casing. <br /> On 21 April 2008,pilot boring MW-13B was initially advanced to 80 feetbsg with 8.25-inch augers; <br /> however,due to bridging sands during the installation of the sand filter pack,the partially completed <br /> well was secured to allow the sand filter pack to settle overnight. This procedure was approved by <br /> EHD. On 22 April 2008, sounding of the filter pack determined inadequate settling had occurred. <br /> The well casing was removed intact,the augers retracted and then re-advanced to 85 feet bsg without <br /> further incident. <br /> Advanced GeoEnvironmental,Inc. <br />