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_ � r,- " <br /> ,.. - mr 2' "+` ''" k -..F <br /> a� �N ems'�,.- <br /> ri.. <br /> IN=- <br /> � ��,; .T�'."7 �. .����� w�,ra,.,r 6A na � raw >:v 7s 1 .,,r «• e. �:,.a <br /> GROUNDWATER TECHNOLOGY <br /> STANDARD OPERATING PROCEDURE <br /> CONCERNING MONITORING WELL INSTI LLKTION <br /> SOP 13 <br /> The bor&,oles for the monitoring wells shall be drilled <br /> using a truck mounted hollow stem auger drill rig. The <br /> F outzide 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 /> t Soil samples can be taken at desired dlepth& by hammering <br /> a conventional split barrel sampler containing precleaned <br /> 2 inch brass sample tubes. <br /> i 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 /> Construction" (See Fierure 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 01aced in the annular space between <br /> the casing and drilled hole to inhibit silt buildup around <br /> i the well. An annulaer seal installed above the &and hack <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 inforinati.on (1) Well Number, <br /> (2) Wellhead Elevation, (3) Depth of Well, (4) Screened <br /> Interval. <br /> i 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 the water <br /> 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, i(3) Groundwater <br /> Monitoring and Sampling P.quipment, (4) Development <br /> Piping and Sparging Equipment. <br /> GRnL'%M.ATER <br /> TECH}UWCV11SC. <br />