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Sr, <br /> CROZ7ND ATER TE*WoL CY <br /> STA.NDk-FLD OPERATING PROCEDURE <br /> CONCMMING MONITORING tt'ELL INST),LLXTTON <br /> SOP 13 <br /> The boreholes for the monitoring wells shall be drilled <br /> using a truck mounted hollow stem auger drill rig. The <br /> outside diameter (O.D.) of the auger should be at minimum <br /> of eight inches when installing 4-inch well atcraen. The <br /> hollow stem auger provides minimal interuption of drill- <br /> ing while permitting soil sampling at specific intervals. <br /> Soil samples can be taken at desired depths by hammering <br /> a conventional split barrel sampler containing precleaned <br /> 2 inch brass sample tubes. <br /> The construction details of the monitoring wells to be <br /> drilled at the site are graphically depicted in the <br /> r_ttached figure titled "Typical Detail of Monitoring Well <br /> Construction" (See Figure 1) . The wells should be cons- <br /> tructed of 4 inch PVC, .020 inch machine slotted screen <br /> and blank casing. The screened portion of the well will <br /> extend 5 feet above and 10 feet below the present wuter <br /> table. An appropriate sand pack as determined by grain <br /> size analysis shall be placed in the annular space between <br /> the casing and drilled hole to inhibit silt buildup around <br /> the well. An annular seal installed above the sand pack <br /> should consist of bentonite pellets overlain by neat <br /> cement or cement grout to the surface. The wellhead shall <br /> be protected below grade within a traffic rated street box. <br /> Each well shall have a permanently attached identification <br /> plate containing the following information (1) Well Number, <br /> (2) wellhead Elevation, (3) Depth of well, (4) Screened <br /> Interval. <br /> Subsequent to installation the wells shall be developed <br /> to remova silts and improve well performance. The well <br /> development shall be conducted by air lifting the water <br /> r within the well until groundwater pumped from the wells <br /> is silt free. <br /> To assure that cross contamination does not occur between <br /> the drilling and development of successive wells all <br /> equipment contacting subsurface soils or ground water <br /> shall be steam cleaned. The steam cleaned equipment <br /> should include but not limited to the following (1) Dril- <br /> ling Augers, (2) Split Barrel Sampler, (3) Groundwater <br /> Monitoring and Sampling Equipment, (4) Well Development <br /> Piping and Sparging Equipment. <br /> GRnI"Y(ri.'4TER <br /> TECHtiuI. i.Isc. <br />