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cgologkal Technics Inc. Page 5 Soil Vapor Extraction Pilot Test Work Plan Project No.770.2 September 17,2003 extraction technology but without the intent of extracting and treating groundwater. The target of the test will be the clay/silt zone present in the vicinity of wells MW-4 and MW-7 at a depth of 50 — 60 feet bgs. An extraction well with a short five-foot screened interval will be installed to intercept the middle of this unit. If this test proves.successful, then this technology can be applied to treat other silt and clay units in the soil column. Details of the pilot test are provided in the following sections. 3.1 -Extraction Well w An extraction well, VEW-1, will be installed approximately ten feet west of MW-7 (see Figure 10 for proposed.well locations). The well construction details are included in the following table: 0.040" slots Filter Pack-- Bentonite Cement Well Diameter Screened Interval -pea gravel - Annular Grout (ft) (ft) Seal (ft) (ft) VEW-1 4 53 - 58' 52'- 58' 48 - 52' 0-48' r Placing the well in this position will determine if high vacuum soil vapor extraction can L address the tight soils at the site. The vacuum influence from the test can also be measured through the screened intervals of existing wells MW-4, MW-7 and possibly MW-5 depending on groundwater elevation. 3.2 Observation Well An additional extraction well VEW-2 will be installed northwest of VEW-1 for the purpose of monitoring vacuum influence from VEW-1. The well construction details are included in the following table: 0.040" slots Filter Pack Bentonite Cement Well Diameter Screened Interval - pea gravel -. Annular Grout (ft) (ft) Seal (ft) (ft) r VEW-2 4" . 53 -58' 52 - 58' 48 - 52' 0-48' L.� Placing the well in this position will determine if soil vapor extraction will reach across the low permeability units present at the targeted depth. r �