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Geological Technics In <br /> Former Moresco Property Page 3 <br /> i <br /> Additional Site Characterization Work Pian <br /> Project No.251.2 <br /> October 13, 1995 <br /> 2.2 Soil Sampling Procedure <br /> Soil samples will be collected for geological and analytical evaluation -at five foot <br /> intervals. A boring log providing sediment description using the U.S.C.S. and field <br /> observations will be maintained by a. professional geologist working under the <br /> supervision of a registered geologist. Soil samples will be collected in 6.0 inch brass <br /> liners using a 2.0 inch modified California split spoon sampler. All soil samples will ' <br /> be-sealed with aluminum foil or Teflon sheets, capped, labeled and placed in a <br /> cooler at 4° Celsius for transport to the laboratory following Chain of Custody <br /> protocol. <br /> Because every soil sample collected will not be submitted for laboratory analysis, a <br /> screening process will be used to,:gather additional information through field <br /> observation noting sediment type, especially grain size and clay content; moisture <br /> content; visible evidence of contamination, i.e., color change due to reduction of iron <br /> or discoloration from hydrocarbons.and'other pollutants, and the readings above <br /> background on a organic vapor meter (OVM). The OVM is a field portable photo <br /> ionization detector that uses a 10.0 eV lamp to detect compounds with, ionization <br /> potential below 10.0 eV (hydrocarbon range). <br /> 2.3 Monitoring Well Installation <br /> The well borings will be drilled using a 8.00 inch outside diameter continuous flight <br /> hollow stem auger owned and operated by a licensed C57 drilling contractor. Soil <br /> samples will be collected for geological and analytical evaluation at five foot <br /> intervals as described above. Soil cuttings will be stockpiled on site as described <br /> above. <br /> x <br /> The monitoring well will be constructed,"using 2.0 inch diameter schedule 40 PVC <br /> casing with flush threads. The screened interval will extend from ten feet above the <br /> water table to ten feet below the water table. Groundwater is expected to be located <br /> between 90 and 110 feet below grade-If a;significant clay unit is encountered during <br /> the drilling of the well, the well may be seated no greater than 3 ft into that fine <br /> grained unit. A #3 sand filter pack swill`surround and extend two feet above the <br /> 0.020" screened interval. Before installing the bentonite seal the well will be surged <br /> using a clean surge,;block to achieve maximum filter pack density. A granular <br /> bentonite transition seal will be installed above .the sand filter pack.and hydrated <br /> with clean tap water. A .surface seal will be achieved by pumping a neat cement <br /> grout (augmented with < 4% bentonite) through the augers as they are withdrawn to <br /> ensure that an integral grout seal is achieved. The well will be secured with a <br /> locking watertight cap encased in flush mounted traffic rated well box. <br />