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Mr.pint Rogers September It, 199, Page 2 On July 20, 1591,Spectrum"Oration drilled a soil borjr-,g at the location of MW-4(Figure 1). The boring was drilled using a truck-mounted drill rig employlna 8Y.-inch outskde-diameter(O,D),hollow- stem augers. Driling was supervised by a Groundwater Technology field geologist who maintained a log of the encountered rnaterWs. A representative of the SJCEHD,Mr.Harlan Knoll,wits present to observe the well installation. The borehole was drilled to a depth of approxilmately 6o.5 feet baow grade. Sell cores were retrieved 2t app mately 5400t Intervals using a California modmed spirt-spoon sampler attached to the drill rig. A copy of the drilling log is attached(Attachment H). Selected soil samples were collected at approximately 5400t Inter and retained for possible laboratory rnafyses. These sog samples were r:ollected In 24nch-dlamct� y 64nch4ong brass WX1. The tubes were sealed with alumfntrn foil, capped,and sealed with pdastic tape. The samples were labeled and placed on Ice In an Insulated cooler for transportation to a Callfomla-certlffed laboratory undor chaln-of-custody protocol. Copies of all applicable Groundwater Technology standard operating procedures(Sops)are attached (Attachment Q. Sail samples were screened In the field for volatile hydrocarbon vapors using a portable photo-ionization detector(PiD). Based on PID readings,field observation,and pro)dmlty to the water table,a son sample was selected for laboratory analyses. One sod sample,cxaliacted at 49 feet below grade,was analyzed ` for the presence of benzene,tdusne,ethylbenzene,and xyiunes(BTE(},and for total petroleum hydrocarbons(TPH)-as-gasollne(BPA Methods 5030/8020/8015). Copies ofthe analytical report and chain-of-custody document are atta(ted(Attachment D). Drill cuttings from the well Installation were placed In three 65-gallon drums,labraled,and stored on site. A composite sample of the sop cuttings from these drums was collected In a brass liner, using the same sampling protocols described above for loll samples collected from the well boring. The groundwater monitoring well that was Installed In this borehoie was constructed of 24nch-dlameter, 8.020-inch machine slotted,Schedule 40 polyvinyl chloride well screen and blank casing. A well filler pack consisting of No. 16 Cisco silica sand was placed In the annular space In the well from the bosom Of the screened Interval to approximately 30 feet Wow grade,extending 5 feet above the screened Interval. After the sand had poen placed In the annular space and before a bentonite seal was added,thcr wail was developed using a surge block. The groundwater monitoring well was twged for 15 minutes,and -- -- then alternately surged and baled for 15 minutes. The wall yielded approximately 35 gallons of water l before suspended sediments In the extracted water attained acceptably low levels. The rlev6pment water was contained In a 55-gallon drurr;labeled,and stored on site. A Chevron reprasentativa was GROUNDWATER L=TECHNOLOCY,INC.