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Page 1 of 3 <br /> Ei <br /> 4 <br /> Nuel Henderson [EH] <br /> From: Adrienne Ellsaesser[EH] <br /> Sent: Tuesday, January 17, 2012 3:42 PM <br /> To: Mike Infurna [EH]; Nuel Henderson [EH] <br /> Subject: RE: Beacon#3641, 1210 E. Hammer Lane, Stockton LOP Case 1125.-Waiver of over-drilling <br />'4 sensitive well destructions <br /> At this point I would concur that the wells located in the tank pit be destroyed by leaving the casings in place.... <br /> Ase- <br /> From: Mike Infurna [EH] <br /> Sent: Tuesday, January 17, 2012 3:24 PM <br /> To: Adrienne Ellsaesser [EH]; Nuel Henderson [EH] <br /> Subject: RE: Beacon # 3641, 1210 E. Hammer Lane, Stockton LOP Case 1125 - Waiver of over-drilling sensitive <br /> well.destructions <br />` ALL of these wells listed/attached with this email were installed thru a PVC <br /> conductor casing placed EXACTLY for the purpose of,protecting the USTs. And <br /> Yes, there is cement grout INSIDE and outside of the conductor casi3ng&of all <br /> these wells to at least 17'bgs. Two wells go much deeper with grout - <br /> w <br /> seals... ..either 44'bgs or 55'bgs, but the,cc is only thru the upper 17-18 feet or <br /> so. <br /> It is highly possible that drilling out wells inside a cement grouted conductor <br /> casing will cause the whole conductor to spin also. May be possible that these <br /> well casings may be pulled out as one whole unit for the short grout seals, but <br /> probably very heavy with 17' of grout inside a 16" or 18" PVC plus outside grout <br /> 4 seal. If they were pulled out as one unit, expect caving pea gravel and then <br /> forming a void in the UST pit. <br /> Exception; MW-5, a single cased, 4" PVC monitoring well screened 50'-75'bgs <br /> and set inside an 18' deep, 18" conductor case and cement:grouted inside the <br /> conductor from the surface to 44' bgs. SW-1. similar to MW-5 except grout goes <br /> to 55' bgs. Too-much grout to pull. or drill? <br /> The nested 2 and 3 cased wells were also;installed inside a either an 18" or 16" <br /> ID PVC conductor casing that was either 10' or 20' long_ These were then <br /> E grouted 0-17 bgs on the inside and their bore logs show EXTERIOR cement <br /> grout too???? My notes don't clarify these 1996 installs. There is only SAND in- <br /> between the deeper casings of the nested wells and they all have.bentonite seals <br /> I o between the different screened intervals (as in, no deep cement grouts). <br /> i With PVC. conductors (fragile) grouted inner and outer (heavy) and nested wells <br /> (large bore outs) or deep surface seals/grouts, pressure grouting these <br /> dirty/contaminated wells may be the only.safe method, albeit inadequate (sealing <br /> 4 <br /> t. <br /> 1/23/2012 <br />