Laserfiche WebLink
' Eckert Cold Vorage A."lany <br /> 7S7Moffat Blvd', Manteca, California November 1, 199S <br /> Underground Tank fnvevigation, Continued Phase I Work Plan Page: 3 <br /> All bona s will be drilled in such a manner as to prevent cross contamination. between <br /> g <br /> strata Exploratory soil bonngs within the unsaturated zone will be backfilled with a <br /> cement and three percent Bentonite mixture <br /> Bonngs into the saturated zone will be dulled to a maximum of twenty feet beneath the <br /> top of the aquifer being explored Any perching layers encountered will be mvestigated <br /> to a maximum thickness of five feet and will be backfilled with concrete slurry, after a <br /> Bentonite seal has been placed If a deeper aquifer is to be investigated, conductor <br /> casing will first be grouted into place to seal off the upper aquifer(s), in series, if <br /> necessary, and drilling will proceed through the conductor casmg after the grout has <br />' been allowed to set properly If evidence of contarrunation is noted during the drilling, <br /> the drilling will be halted until the responsible professional determines the advisability of <br /> deeper drilling <br /> Upon termination, the boring into the saturated zone will be completed as a monitoring <br /> well and backfilled with concrete grout, after a Bentonite seal has been placed The <br /> boring for the monitoring well will be of a diameter at least four inches greater than the <br /> two inch diameter of the well casing to be used <br /> 1 . The cuttings from the drilling operation will be contamenzed on-site during drilling for <br /> proper disposition The proper method of disposal will be dependent upon results of <br /> laboratory analysis this disposal v ll be the responsibility of the client unless other <br />' arrangements have been made <br /> 32 Well Consti urhon <br /> All materials used in well construction will be thoroughly cleaned prior to introduction <br /> into the boimg A Bentonite or cement and Bentonite grout will be placed at the <br /> bottom of the boring as necessary After the seal has been allowed to set long enough <br /> to support the weight of the casing, a two inch diameter well casing (stainless steel or <br /> PVC)with end cap and factory perforations for placement in the saturated zone(taking <br /> into account seasonal variation)will be placed in the boring The screen and filter pack <br />' sizes will be as noted in the well construction drawing The casing and end caps will be <br /> threaded or joined by stainless steer screws, no PVC cement will be used The filter <br /> pack will extend two fleet above the perforated zone A Bentonite seal 2 to 3-feet thick <br /> will be placed in the annular space above the filter pack followed by a cement grout to <br /> the surface Seal and filter pack elevations may change based on the underlying <br /> geology(A.ppendix B) <br /> • <br />