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Mr. Michael Kith May 11, 2017 dated June 17, 2013. Overdrilling was required for MW-15, VW-4 and SP-7. Destruction via blasting for MW-15 and VW-4 was approved in an email from SJCEHD dated April 22, 2015 (Attachment 1). Arcadis proposed pressure grouting all remaining wells in a Well Destruction Work Plan Addendum dated September 12, 2016 (Arcadis 2016). Upon receipt of emailed photos of the utility line near VW-4 on April 25, 2017, SJCEHD requested an additional workplan in an email to Arcadis dated April 25, 2017, (SJCEHD 2017), provided herein. Wells VW-4 and MW-15 have health and safety issues associated with their currently approved destruction methods. • VW-4 is adjacent to identified subsurface utilities that would be damaged by over drilling (Attachment 2); • MW-15 is adjacent to a bus stop on Pacific Avenue (a major arterial roadway), and set up of a drill rig would significantly disrupt traffic, as the drill rig would have to be parked perpendicular to the sidewalk taking up multiple lanes of a major city roadway. Arcadis still recommends that all remaining wells be abandoned using the pressure grout method.As the sparge wells are'/-inch diameter,Arcadis proposes to utilize a 3/8-inch diameter hose connected to a hand pump to tremie grout down the well and displace and contain groundwater. Once the well is grouted, pressure will be applied per standard pressure grouting methods. Standard tremie techniques will be deployed at wells VW-4 and MW-15. Should the method prescribed above for the sparge wells prove unsuccessful, Arcadis proposes to overdrill all sparge wells with 8-inch auger using hollow stem drilling techniques. As stated previously, a stinger cannot be used to keep the drilling augers centered on the well, which makes this method a lesser preferred method. Additionally, should SJCEHD deny the request to destroy MW-15 using pressure grouting techniques, Arcadis proposes blast perforation (well detonation) as an alternate method. Should this option be decided upon, Arcadis will provide blast plans from a certified subcontractor. Note that blast perforation is not an option for onsite wells and sparge wells due to the access agreement with Target. For wells abandoned via pressure grouting or blast perforation techniques, an area one foot larger in diameter than the original borehole will be excavated around the outside of each well casing to a depth of 3 feet below ground surface (bgs) per SJCEHD requirements. Each well casing will then be cut off 6 inches above the bottom of the excavation and removed.Additional grout will be added as needed to obtain a mushroom cap. The borehole will be backfilled with soil to just below the surface. The surface will be completed to match existing conditions at each well location (e.g., asphalt, concrete, etc.). Boring Logs are provided as Attachment 3. Attachment 4 provides the available soil data(Gettler-Ryan 2002; Stantec 2012; Geotracker 2016). Investigation Derived Waste Soil cuttings generated during well destruction activities will be containerized pending characterization and disposal. Soil cuttings will be removed and transported by Chevron's disposal contractor to an appropriate disposal facility. Water displaced during well grouting or generated during steam cleaning will Page: arcadis.com 2/4 351515 170511-Well Destruction Work Plan Addendum 3.docx