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1 <br /> 1444 MARIPOSA <br /> WKA No. 2938.03 <br /> l February 1, 1996 <br /> v Page 4 <br /> TPHg concentration of 96 mg/kg. Stockpile #2 was generated during the construction of an <br /> access ramp and was therefore not sampled. <br /> PROPOSED SCOPE OF WORK <br /> Three soil borings will be drilled to an anticipated depth of 85 feet below surface grade using a <br /> truck-mounted drill rig equipped with hollow-stem augers. All drilling equipment will be steam <br /> cleaned between borings to reduce the potential of cross-contamination; rinse water generated <br /> during steam cleaning will be pumped into labelled 55-gallon drums and stored on site. All soil <br /> cuttings generated during drilling will be placed on and covered with plastic. <br /> Soil samples will be obtained at maximum intervals of five feet and/or at significant stratigraphic <br /> changes beginning at 5 feet below grade and continuing to the total depth of the borings. Soil <br /> samples will be obtained with a modified California sampler containing clean two-inch diameter, <br /> six-inch long brass tubes. All sample tubes will be sealed with Teflon sheets, plastic caps, duct <br /> tape, and preserved on ice. Soils encountered during drilling will be logged in the field by a <br /> qualified geologist or engineer using the Unified Soils Classification System. Each sample will <br /> also be field screened using an organic vapor analyzer and observations of our field geologist or <br /> engineer to assist in selecting soil samples for laboratory analysis, if warranted. <br /> The soil borings will be converted into ground water monitoring wells (Plate 2). The wells will <br /> be constructed using four-inch diameter, flush jointed, Schedule 40 PVC casing; 0.02-inch slotted <br /> casing will be used for the screened interval. Sand will be placed in the well annulus as a filter <br /> pack. The filter pack will extend from the bottom of the screened interval to approximately two <br /> feet above the top of the screened interval. A minimum two-foot thick bentonite seal will be <br /> placed in the well annulus above the filter pack. A grout seal consisting of Portland Cement and <br /> bentonite slurry will be placed into the well annulus above the bentonite seal. The wells will be <br /> completed with locking well caps and flush-mounted, traffic-rated well covers. The location of <br /> the wells and top of casing elevations will be surveyed to the nearest 0.01 foot. A diagram <br /> showing construction details of the proposed ground water monitoring wells is shown on Plate 3. <br /> WALLACE-KIM <br /> Recycled paper fir ASSOCLAMS INC. <br />