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HORIZON ENVIRONMENTAL INC. <br /> Specialists in Site Assessment,Remedial Testing,Design and Operation <br /> fir •�,'- ' .t ,,.- <br /> v r- <br /> January 11,2013 ! - z �' <br /> Ms. Lisa Medina I A; �' '^ <br /> San Joaquin County Environmental Health Department r + t.A w <br /> 1868 East Hazelton Avenue; <br /> Stockton,CA 95205 <br /> Subject: Well Destruction Work Plan and Permit Applications <br /> Beacon Station No. 3641, 1210 East Hammer Lane, Stockton,California <br /> MW <br /> Mw3 <br /> Ms. Medina: µ M"0-' ?q <br /> At the request of Ultramar Inc. (Ultramar), Horizon Environmental Inc. (Horizon) is <br /> submitting this work plan and permit applications for the destruction of 22 wells associated <br /> with the subject site. The San Joaquin County Environmental Health Department (EHD) <br /> requested the work plan in an e-mail dated 9 January 2013. The wells shall be destroyed in <br /> accordance with the California Well Standards Bulletins 74-81 and 74-90, San Joaquin <br /> County Environmental Health Department (EHD) Well Standards, and approved exceptions <br /> as stated in the EMD 6 February 2012 letter. <br /> Wells to be destroyed include 13 monitoring wells (MW-112/3/41516/7/9/10111/12/13/14), 8 <br /> vapor extraction wells (VW-1/213/4/5/6/7/8) and air sparge well SW-1 located as shown on <br /> the enclosed site plan. Well MW-2 is located on parcel APN 094-030-43 owned by 99c <br /> Only Store(99c). The remainder of the wells are located on the three parcels APN 094-030- <br /> 11, APN 094-030-12 and APN 094-030-13 owned by Shadrall Hammer Lane LLP <br /> (Shadrall). Right-of-entry agreements entered into by Ultramar and the parcel owners are <br /> attached to the two permit applications, one application per parcel(s)owner. <br /> The triple-completion well MW-1/VW-112, the double-completion wells;VW-3/41,VW-5/6 <br /> and VW-718, and single-completion wells SW-1' and MW-5 were installed in conductor <br /> ` casings within the current UST basin backfill. Horizon obtained approval from the EHD to <br /> destroy these wells_by,,pressure grouting the casings dupe their proximity to the USTs. Wells <br /> NW-2'througli MW-4; MW-6, MW--7, MW-9, MW-10 and MW-1 I through MW-14 are <br /> located outside of area sof residual contamination With the exception of MW-10, .,t <br /> ` groundwater collected from these wells during the last sampling event (30 June 2011) did <br /> °f t not contain dissolved analytes. These wells shall also be destroyed by pressure grouting. <br /> The estimated grout volumes required to destroy the wells are summarized in the enclosed <br /> Pii�� table. <br /> In the pressure grouting method, neat cement shall be pumped into the well casings via <br /> tremie set within three feet of(lie total depth of the well casings. The grout level shall be <br /> brought to within 5 feet of the surface. The casing shall be air pressurized to 25 pounds per <br /> square inch for approximate 10 minutes. The grout will be topped off until stabilized within — <br /> 5 feet of the surface. After the grout level stabilizes, the top 5 feet of the well shall be <br /> 4970 Windplay Drive,4C5 - EI Dorado Hills,CA 95762 - (916)939-2170 - FAX(916)939-2172 <br /> P.O.Box 5283 - Bakersfield,CA 93388 - (661)589-8389 - FAX(661)589-1456 <br />