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1444 MARIPOSA ROAD <br /> WKA No 2307 02 <br /> December 15, 1993 <br /> Page 3 <br /> FIELD INVESTIGATION METHODOLOGY <br /> i <br /> ' Soil Boring and Monitoring Well Construction <br /> Three soil borings were drilled with a truck-mounted Mobile B-61 drill rig equipped with 10-inch <br /> diameter hollow-stem augers supplied by B & F Drilling Soil samples were collected from each <br /> ' boring at five-foot maximum intervals with a modified California sampler equipped with clean, <br /> two-inch diameter, six-inch long brass tubes, samples and drill cuttings were described in the <br /> ' field by an experienced engineer from our firm using the Unified Soil Classification System <br /> (USCS) Logs describing the soils encountered in each boring are presented on Plates 6 <br /> ' through 15 <br /> Sample tubes were sealed with Teflon' sheets, plastic end caps and duct tape to reduce volatile <br /> hydrocarbon loss The samples were screened in the field with an organic vapor analyzer (OVA) <br /> to evaluate potential hydrocarbon content Selected samples were placed in an ice chest <br /> ' containing ice, and submitted under chain-of-custody to a Cali fornia-cerufled. laboratory for <br /> analysis of TPHg using Modified EPA method 8015 and BTEX using EPA method 8020 <br /> The soil borings were subsequently converted into ground water monitoring wells Each well <br /> ' was constructed using four-inch diameter, flush pointed, Schedule 80 PVC casing, 0 02-inch <br /> slotted casing for the screened interval Number 3 Monterey sand was placed in the well annulus <br /> ' as a filter pack The filter packs extended from the bottom of the screened interval to <br /> approximately two feet above the top of the screened interval A two-foot thick bentonite seal <br /> ' was placed in the well annulus above the filter pack A grout seal consisting of a Portland <br /> Cement and bentonite slurry was tremied into the well annulus above the bentonite seal Each <br /> well was completed with a locking well cap and a flush-mounted, traffic-rated well cover The <br /> ' wells were constructed under the supervision of a California Registered Geologist <br /> IN51 <br /> ' WALLACE KUHL <br /> R-y&dpiper Gr ASSOCIATES INC <br />