SITE INFORMATION AND CORRESPONDENCE FILE 2

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Page 1 of 5 I Vicki McCartney [EH] From : Vicki McCartney [EH] Sent: Friday , May 02, 2014 12:58 PM To: 'Westhoff, Brian' Cc: Gabriel Gonzalez [EH] Subject: RE: Arco 2130, Stockton Regulatory Response Good afternoon Brian , Gabe Gonzalez, the new case worker for ARCO Station No. 2130 at 7906 North EI Dorado Street in Stockton , and I visited this site on Wednesday, April 30, 2014. 1 have also discussed with Adrienne Ellsaesser, Program Coordinator, Stantec's proposals for this site submitted in Well Destruction Work Plan. The following is a list of issues concerning the work plan: 1 . Under Well Destruction Activities on page 2, second paragraph , AS-2 and AS-3 are listed twice among the fifteen wells that Stantec proposes to require a variance. 2. On page 2 of the work plan , Stantec proposes to place a mushroom cap at one foot below surface grade ((bsg) when pressure grouting MW-5 , MW-6, MW-13, MW-20, AS-2, AS-3, VW-3, VW-6 , VW-8, VW-101 VWA 1 and MW-3A/B; however, on page 3 of the work plan Stantec proposes to air knife to three feet bsg and cut off the casing at three feet bsg . There is no mention of a mushroom cap. Stantec does state that "Given the risks associated with the subsurface structures at MW-6, AS-2, AS-3, VW-3, VW-6 and VW-11 , Stantec recommends air knifing to approximately one ft bgs, and each well casing will be cut at approximately one ft bgs. The borehole locations will be backfilled and resurfaced with appropriate materials to match the existing grade." Again there is no mention of a mushroom cap. If you propose to pressure grout some of the wells, you must include forming a mushroom cap. Cutting off the casing at one foot bsg will not be deep enough to form a one-foot mushroom cap, with grout six inches below and six inches above the cut-off casing. I suggest that you propose hand digging to two feet bsg , cut off the casing at 1 .5 feet bsg , form a mushroom cap from two to one foot bsg , and finish off the last foot bsg with appropriate materials to match the existing grade. am waiting to hear from Nuel Henderson as to whether MW-14, MW-19 and MW-21 should be pressure grouted or over-drilled. Since diesel was found in soil when installing these three wells, I believe that these wells should be over-drilled. Once Nuel has commented about these three wells, I will let you know. In conclusion, our agency will allow variances to pressure grout wells in or near the USTs, product lines, electrical lines and near the Healy tank. However, the work plan in its current version will not be acceptable and must be revised . Please contact me if you have any questions concerning this email. Thank you Brian . Vicki McCartney, Senior REHS San Joaquin County Environmental Health Department 1868 East Hazelton Avenue Stockton, California 95205 Phone: (209) 468-9852 Email: vmccartneV(a)sicehd .com 5/2/2014