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KLE ] NfELDER <br /> to be used Installation of the sand may require that the sand be tremmied, using clean <br /> water <br /> 0 A 3- to 5-foot bentonite plug is placed above the sand pack to provide a seal against <br /> surface water infiltration and to reduce the potential for cement grout to infiltrate into the <br /> ' water <br /> • The remaining annular space is filled to the surface with cement bentonite grout <br /> ' 0 The wells are secured in an aboveground or underground locking stovepipe The well <br /> heads may be enclosed in a water tight cement utility box set flush to the ground surface <br /> when located in a traffic area <br /> B-3 2 Monitoring Well Development <br /> ' The wells are developed to reduce the effects of drilling on the formation and to increase the <br /> effective hydraulic radius of the wells <br /> ' Monitoring wells are generally developed 24 to 48 hours after installation to allow the grout to <br /> set Each well is first sampled with a clear disposable bailer to visually inspect for a hydrocarbon <br /> layer or sheen If no product layer or sheen is observed on the water, the well is developed by <br /> surging, pumping or bailing Surging along the screened interval of the well is performed to <br /> draw the sediment from the formation into the filter pack and the well, and to set the sand pack <br /> 1 Development continues until the discharge runs relatively clear of fines Approximately 5 to 10 <br /> well volumes are generally removed from each monitoring well Discharge water is stored in 55- <br /> gallon drums and left on site for later discharge or disposal by the client, depending on laboratory <br /> ' results The drums are labeled with the date, well number, and a contact person and phone <br /> number <br /> ' B-3 3 Equipment Decontamination <br /> To reduce the potential for cross-contamination between wells, developing equipment is washed <br /> ' in a trisodium phosphate or non-phosphate detergent solution and rinsed in distilled water or <br /> steam cleaned prior to use in the next monitoring well <br /> 1 <br /> 20-1311-40 EO112019RO39 Page S-5 <br /> ©1999,Klemfelder,Inc January 20, 1999 <br />