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.S <br /> a <br /> -- GROUNDWATER TECHNOIAGY <br /> STANDARD OPERATING PROCEDURE <br /> CONCERNING MONITORING WELL INSTALLATION <br /> SOP 13 <br /> The boraholes for the monitoring wells shall be drilled <br /> using a truck mounted hollow stem auger drill rig. The - <br /> a outside diameter (O.D. ) of the auger should be a minimum <br /> of eight inches when installing 4-inch well screen. 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 /> 4 <br /> The construction details of the monitoring wells to be <br /> drilled at the site are graphically depicted in the <br /> attached figure titled "Typical Detail of Monitoring Well <br /> j 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 /> t extend 5 feet above and 10 feet below the present water <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 remove silts and improve well performance. The well <br /> development shall be conducted by air lifting ohe wells <br /> the water <br /> r within the well until groundwater pumped <br /> s is silt free. <br /> To assure that cross contamination does not occur between <br /> the drilling and development of successive veils all <br /> equipment contacting subsurface soils or ground water <br /> _ shall be steam cleaned. The steam cleaned equipment <br /> Dril- <br /> should include but not limited to the following (1} <br /> ling augers, (2) Split Barrel Sampler, (3 ) Groundwater <br /> Monitoring and Sampling Equipment, (4) Well Development <br /> Piping and Sparging Equipment. y <br /> - GRnf,D4A ATER <br /> ```� TutiNuwc) lu <br />