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Page 9 of 15 <br /> VEW-16 do not qualify for pressure grout destructions as <br /> they are within the line of estimated residual <br /> contamination. VEW-19 and VEW-22 are also within the <br /> contaminated area and also had soil vapor hits. As such, <br /> these wells do not qualify for pressure grout destruction <br /> either. <br /> MW-16 and MW-32 are both within areas of contamination <br /> as noted on Figure 14, 9-22-2010-AECOM and Figure 15, <br /> 9-22-2010-AECOM. Neither well qualifies for pressure <br /> grout. These wells are to have the contents removed also. <br /> Please submit a revised list of wells that includes the <br /> above noted modifications. After I have received and <br /> approved the list, you will be notified to submit SJCEHD <br /> Well Permit Applications, Master File Record forms, and <br /> fees. <br /> As a precaution, please check with your drilling contractor <br /> and see what steps and materials will be needed and used <br /> to ensure that the augers or drill casings will stay centered <br /> on the small diameter casings during the drill out <br /> procedures. Recently, problems have developed at other <br /> sites where three-quarter and one-inch PVC casings were <br /> scheduled to be drilled out. The driller had no way to stay <br /> centered during drilling and the augers went off-center <br /> within the first 5-10 feet. I stopped the drilling/destruction <br /> process until they could provide an adequate method of <br /> staying on-center and removing the contents of the well. <br /> The only method that was successful for this site was <br /> using very large augers (15-inch outer diameter) with a 11- <br /> inch inner diameter that encompassed the hardened 8- <br /> inch grout of the well to be destroyed and provided a self- <br /> centering way to reach total depth. The 15-inch augers <br /> were left in place and smaller augers (6 or 8-inch) were <br /> then used to drill inside the large augers and remove the <br /> contents of the well. Very labor intensive and time <br /> consuming and not a procedure I recommend initially, but <br /> was used after multiple field attempts to drill out these <br /> small wells failed. I recommend you have a Plan B in case <br /> the primary method you chose fails to meet the destruction <br /> objective of removing the contents. <br /> Thank you in advance for your cooperation. You may <br /> 12/20/2011 <br />