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ftow -... 21 March 2003 AGE-NC Project No. 95-0114 Page 8of10 In addition, soils encountered in the borings will be visually classified by an AGE geologist in accordance with the Unified Soil Classification System (USCS), and the soil samples will be field screened for the presence of volatile organic compounds using an organic vapor meter (OVM) equipped with a photo-ionization detector (PID: Thermo Environmental 580B, 10.0eV [or equivalent], calibrated to isobutylene). 4.1.2. Multi-level Ground Water Monitoring Well Completion Four soil pilot borings will be established to the proposed 150 feet bsg for completion as `multi- level' ground water wells. If field observation indicate contamination in the total depth of the monitoring well pilot boring, the well construction will exceed the proposed 150 foot target depth by an additional 30 feet in depth. This will allow for the completion of the well in the deepest interval through the center of the CMT well casing. Each `multi-level' well will be completed in a single soil boring utilizing 1.7-inch 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 %-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. 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(poll plug -,oated 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 filled to the ground surface with a cement grout.The grout mixture will consist of Type I/II portland neat cement and not more than 6 gallons of water per 94-pound sack of cement, and will be placed by pumping through tremmie pipe. A grouting inspection will be scheduled with EHD personnel. A proposed well construction diagram is depicted in Figure 4. 4.2. WELL DEVELOPMENT Development of the proposed wells will consist of a combination of balling with a 1/4-inch stainless steel bailer to remove the major portion of fine-grained sediment from inside the well, surging to Bush out or draw in sediment from the filter pack and additional ground water evacuation(purging) with a peristaltic pump consisting of polyethylene tubing and a ball check valve to finish the removal Advanced GcoEnvironrnental,Inc.