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El <br />SECTION 76 <br />SPECIAL <br />Page 8 of 12 <br />(02/17) <br />7. Contractor shall place the sand pack into the annular space around the <br />screened interval. Clean water and a tremie pipe may be used to assist with <br />sand pack placement. If the well assembly is installed through the hollow <br />stem augers, the augers shall be pulled slowly during sand pack installation. <br />8. Contractor shall minimize bridging of the sand by pouring the sand in the <br />bore hole gently and not in large quantity. Patience shall be exercised by the <br />Contractor. <br />9. Contractor shall monitor the sand pack settlement by measuring the sand <br />level with a weighted tape. Contractor shall also monitor the top of the well <br />casing to detect any movement due to settlement or from drive casing <br />removal. <br />10. Contractor shall periodically gently surge the water inside the well casing and <br />screen to compress the sand pack while placing the sand. Contractor shall <br />measure the top of the sand pack periodically <br />11. Contractor shall add sand shall until the sand pack is above the top of the <br />screened interval as shown on the groundwater well figure. <br />12. Once the placement of the sand packed interval is completed, the contractor <br />shall measure and record the depth to the top of the pack in the presence of <br />the Engineer. <br />13. Contractor shall install bentonite seal in the annular space above the sand <br />pack. Add bentonite gradually to avoid bridging. Contractor shall measure the <br />depth of the bentonite plug using a weighted tape. <br />14. Contractor shall hydrate the bentonite seal after placement with five (5) gallons <br />of distilled or Engineer -approved water for each 2.5 vertical feet of seal. <br />15. Contractor shall allow the bentonite to hydrate according to manufacturer's <br />specification or according to a field test demonstrating the time required for <br />bentonite to hydrate. <br />16. Contractor shall pump neat cement through a tremie pipe filling the annular <br />space from the top of the bentonite seal upward. The bottom of the tremie <br />pipe shall be maintained below the top of the cement to prevent free fall and <br />bridging. <br />LANDFILL AREA 513 -SEC 76 -GW Well Specs <br />