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2 r SPJVIRONMENTAL GROUP, INC. <br />rARDENT <br />1627 Army Court July 12, 2017 <br />Stockton, California Project No. 100834003 <br />According to the previous report, the well was installed within an 8-inch diameter borehole and <br />constructed with 2-inch diameter, threaded, polyvinylchloride (PVC) well casing. Prior to <br />beginning the work, total depth of the well casing was measured at approximately 21.9 feet <br />below the ground surface (bgs); groundwater was encountered at a depth of approximately 6 <br />feet bgs. The well box was subsequently removed and a bulldog bit was used to destroy the <br />upper 6 feet of casing. At approximately 6 feet, hard drilling conditions were encountered and <br />the augers started to bind on an approximately 8-inch diameter steel conductor casing. Once <br />the augers were removed, an approximately 2 foot piece of conductor casing and an additional <br />2 feet of well casing were removed. At the end of our attempted abandonment activities, <br />approximately 8 feet of well casing had been destroyed or removed. <br />The objective of the decommissioning activates is to remove any feature that might act as a <br />conduit for contaminates to enter groundwater due to a possible surface release. Based on the <br />work completed to-date, the well casing above groundwater (i.e. possible conduit) has been <br />removed. Therefore, I propose to fill the remaining void, from groundwater to surface with a <br />neat cement grout and cap the area with concrete. Eight-inch hollow stem augers will be <br />adjacent to the previous boring depth (approximately 6 to 8 feet bgs) and will be used to tremie <br />the neat cement grout into the borehole. The upper 1-foot will be capped with concrete. <br />Although the remaining portion of the casing below the groundwater table had not been <br />removed, the agitated soils produced during drilling activities below the groundwater table have <br />likely filled the remaining well casing with slough. This remaining casing, therefore, would not <br />be considered an environmental risk to the site. <br />100834003 Revised Scope