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Report-Monitoring Well Abandonment � Page 3 <br /> Former Valley Water Treatment <br /> GPE Project No. 480.3 <br /> March 3, 2010 <br /> 2.0 Well Abandonment <br /> The following sub-sections describe the' work completed to properly abandon the <br /> p P P Y <br /> groundwater monitoring wells. <br /> i <br /> 2.1 Preparatory Work <br /> An Work Plan and application for a permit to abandon the wells and a Work Plan <br /> describing the field procedures was submitted to the SJC-EHD. The Work Plan was <br /> approved and the permit was issued on February 5, 2010. The permit is attached in the <br /> appendix. The SJC-EHD was subsequently,notified that the final well abandonment was <br /> scheduled for February 25, 2010.. <br /> 2.2 Pressure Grouting <br /> r On the appointed day, V&W Drilling (C-57 # 720904) mobilized to the site for the <br /> Fr.+ purpose of abandoning the wells. The following steps tasks were performed to complete <br /> the well abandonment by pressure-grouting. <br /> The well boxes lids were opened and removed as were the locking caps and locks. The <br /> dedicated tubing was removed from each well. <br /> V&W Drilling personnel prepared Type I/II neat cement for use as grout. Each well was <br /> sequentially fitted with a.2-inch pressure cap. Neat cement was then pumped into each <br /> well using a pneumatically actuated grout pump and a tremie pipe.- Pumping continued <br /> until a positive pressure of approximately 25 pounds per square inch (psig) was reached <br /> at each wellhead, and the pressure was maintained for several minutes. The volume of <br /> each 54-foot long, 2-inch diameter, well casing was calculated at 8.9 gallons. The <br /> volume of grout pumped was monitored to verify that sufficient grout was used to <br /> completely fill the casing and the sand pack around the perforated intervals. The volume <br /> of the grout pumped into each well was obtained by monitoring the level in the grout <br /> container. <br /> The following table gives the actual volume of grout pumped. <br /> Well Grout Pumped Variance from <br /> (gallons) Csg Volume <br /> MW-1 26 +292% <br /> MW-4 .25 +281% <br /> - The actual grout pumped exceeded the calculated casing volume in all cases, indicating <br /> the grout reached and filled the pores of the filter pack. <br /> 2937 Veneman Avenue;Suite B240Geo-Phase_Environmental Inc. Phone: (209)569-0293 <br /> Modesto,Ca 95356 Fax: (209)569-0295 <br />