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' 11 June 2001 <br /> AGE-NC Project No. 96-0232 <br /> ' Page 7 of 11 <br /> ' • BTEX and MTBE by EPA Method 8020; <br /> • Methanol, ethanol, ethylene dibromide (EDB), 1,2-dichloroethane (1,2-DCA), tertiary <br /> butanol (TBA), di-isopropyl ether (DIPE), ethyl tert butyl ether (ETBE), tert amyl methyl <br /> ' ether(TAME), and confirmation of MTBE by EPA Method 8260 Modified; and <br /> • Total lead by EPA Method 6010/200.7/239.2. <br /> Laboratory reports for soil analysis, testing methods, laboratory quality assurance/quality control <br /> (QA/QC) reports, and sample chain of custody documentation will be presented in a report with <br /> findings and recommendations. <br /> 3.3. MULTI-LEVEL WELL INSTALLATION AND DEVELOPMENT <br /> Each multi-level well will be single-completed as ground water monitoring wells utilizing 1.7-inch <br /> diameter polyethylene(outer) tubing. The inner tubing consists of multiple t/2-inch diameter teflon <br /> tubes partitioned into separate chambers; a stainless steel, 0.02-inch screen will be wrapped around <br /> ' each perforated area of the tubing. Additional multi-level design literature is contained in Appendix <br /> A. <br /> Based on review of lithologic and analytical data derived the previous CPT investigation(Figures <br /> 3 and 4),AGE proposes multi-level screen intervals between 70 and 80 feet bsg,between 95 and 105 <br /> feet bsg, between 115 and 125 feet bsg and between 140 and 150 feet bsg; however, the proposed <br /> screen depths may vary based on the lithologic findings from each continuous core. <br /> After deploying the multi-level well casing in the hollow stem boring, a filter pack material <br /> consisting of pre-washed#212 Lonestar sand will be added through the augers to approximately two <br /> feet above each screened interval. A bentonite seal (pell plug-coded bentonite pellets)will be placed <br /> ' between filter pack intervals to minimize the potential for cross contamination into the screened <br /> section of the well. The bentonite seal will be formed by pouring bentonite pellets into the annulus <br /> and allowing them to settle on the filter pack. The remaining annular space above the uppermost <br /> ' screen interval and bentonite seal will be filled to the ground surface with portland cement grout. The <br /> grout mixture will consist of Type I/H portland neat cement and not more than 6 gallons of water per <br /> 94-pound sack of cement. The grout will be placed by pumping through tremmie pipe. A grouting <br /> ' inspection will be scheduled with PHS-EHD personnel. A proposed well construction diagram is <br /> depicted in Figure 6. <br /> Advanced GeoEnvirontnentel,Inc. <br />