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' log. Retrieved soil samples in 6-inch steel cylinders will be sealed with plastic end-caps ' and duct tape and labeled for subsequent description and/or archiving. Soil samples will either be logged in the field during drilling or in the laboratory after drilling is completed. ' At a depth of approximately 70 feet BGL, drilling will be suspended for a maximum of 12 hours in order to allow water from a perched groundwater zone at that depth to fill the inside of the augers such that a grab groundwater sample can be collected. The ' groundwater sample will be collected using a new disposable bailer, and the sample will be immediately placed in appropriate containers for subsequent laboratory analysis. The procedures used for sample collection, sample preservation and transportation, and laboratory analysis for 33 parameters will be identical to those identified in the Sampling and Analysis Plan, October 6, 2004 (amended October 22, 2004), with the exception that no purging of groundwater will be conducted prior to sample collection. Should flowing sands become a problem during drilling, then potable water will be used inside the augers to provide a back pressure. The addition of potable water to help ' control flowing sands will not be used prior to collecting a grab groundwater sample. With the augers at 125 feet BGL, well construction will be initiated. Figure 2 shows an ' anticipated well construction diagram for MWS. Well construction materials are anticipated to include a 20' section of flush-thread, 2" diameter, 10-slot, PVC well screen with a screw-on end-cap at the base of approximately 110' of flush thread, 2" diameter, ' PVC well casing. The sandpack will consist of#2 driller's sand surrounding the screened interval and extending approximately 2 feet above the top of the screen(the top 1-foot of sandpack will be a fine grained driller's sand). A 2-foot thick bentonite seal will be placed on top of the sandpack. A grout mixture will fill the remainder of the annulus between the well casing and the well boring to the surface. The grout mixture will consist of 5 to 10 gallons of potable water for each 94 lbs bag of Portland cement with up ' to 5%by weight of bentonite added to control shrinkage. The well materials shall be emplaced inside the hollow stem augers, and the augers shall be progressively removed as the well construction materials fill the bottom portion of the augers. All materials used during well construction will be new and will be kept in original packaging away from potential sources of contamination, until ready to be used. ' Care will be taken to assure that well materials are properly placed in the well boring. If the augers are filled with water, then the water may be pumped out of the augers prior to building the well and disposed of in the adjacent wastewater pond. The accumulation of ' the sandpack and bentonite seal will be monitored by measuring the depth to the material after every few bags of material are placed in the well in order to assure that bridging of the material does not occur. Additionally, the sandpack will be briefly surged prior to ' installing the bentonite seal. The bentonite seal will be hydrated for at least one-hour prior to any grouting activities. Grout will be completed using a tremie pipe lower to near the top of the bentonite seal and equipped with a 90 degree elbow at the base in order to avoid disturbing the bentonite seal during grouting. June 21,2005 Page 4