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• 25 January 2001 AGE-NC Project No 99-0559 Page 11 of 14 be put in properly Iabeled DOT-approved 55-gallon drums Rinseate generated during the drilling process will be containerized in properly labeled DOT-approved 55-gallon drums and will be stored on-site in an area lacking public access Disposal alternatives will be evaluated based on results of soil and water analysis 63 MULTI-LEVEL GROUND WATER MONITORING WELL COMPLETION All `multi-level' monitoring wells will be installed utilizing a B-95 truck-mounted, hollow-stem drill rig with 8-inch O D hollow-stem augers Each `multi-level' well will be completed in a single soil boring utilizing 1 7-mch outer diameter polyethylene tubing containing segregated vertical chambers that can be individually completed as monitoring wells at different depths The Inner tubing consists of seven '/2-inch diameter or four larger diameter Teflon tubes partitioned into separate chambers running the length of the casing Each multi-level well casing will be prefabricated at the factory with the proposed perforated intervals, a stainless steel, 0 02-Inch screen will be wrapped around each perforated interval of the tubing Additional multi-level well design literature is contained in Appendix B . After deploying the multi-level well casing in the hollow stem boring, a filter pack material consisting of pre-washed #3 Lonestar sand will be added through the augers to approximately two feet above each screened interval A bentonite seal (pell plug-coated bentonite pellets) will be placed between filter pack intervals to minimize the potential for cross contamination between the screened sections of the well The bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing them to settle on the filter pack The remaining annular space will be tilled to the ground surface with a cement grout The grout mixture will consist of Type I/11 portland neat cement and not more than 6 gallons of water per 94-pound sack of cement The grout will be placed by pumping through tremmie pipe A grouting inspection will be scheduled with PHS-EHD personnel A proposed well construction diagram is depicted in Figure 6 As previously noted, the final depths of the screened intervals, and therefore the final well design, will be selected based on interpretation of the CPT data AGE notes that the use of the coated bentonite pellets is likely to result in erroneous ethanol concentrations due to use of ethanol in the coating material The elevated ethanol results last approximately 6 months 64 WELL DEVELOPMENT Development of the proposed wells will consist of a combination of bailing with a '/a-inch stainless . steel bailer to remove the mayor portion of fine-grained sediment from inside the well, surging to flush out or draw in sediment from the filter pack and additional ground water evacuation (purging) Advanced GcuEnwoninental,Ine