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f <br /> t <br /> Harding Lawson Associates <br /> April 5, 1994 <br /> 276901 <br /> San Joaquin County <br /> Mr Harlin Knoll <br /> Page 4 <br /> least 48 hours prior to grout emplacement, a grout inspection will be scheduled with the SJCEHD <br /> Samples will be collected from the borings, starting at the groundsurface and at five foot intervals <br /> using a split barrel sampler lined with stainless-steel tubes A photoionization detector (PID) will be <br /> used to screen the soil samples for volatile organic vapors The samples will be logged, sealed, and <br /> placed on ice for delivery to a state-certified analytical laboratory (see Task 3) Proposed boring <br /> locations are presented on the attached site plan Borings will be logged by an HLA geologist using the <br /> Unified Soils Classification System <br /> There is an existing monitoring well located approximately 200 feet south of Site A HLA will utilize <br /> this upgradient well as a control point to assess local groundwater flow in conjunction with the newly <br /> installed wells <br /> HLA proposes to collect groundwater samples and measure water levels in the two newly installed <br /> groundwater monitormg wells Prior to sampling, a minimum of five well volumes will be removed <br /> using a stainless steel bailer or a submersible pump During development, groundwater temperature, <br /> pH, and conductivity will be monitored After well development, one groundwater sample will be <br /> collected Samples will be submitted to a California DHS-certified laboratory for analyses (see Task 3) <br /> All samples will be collected using steam cleaned and/or TSP cleaned and rinsed sampling devices <br /> All samples will be immediately removed from the sampler, placed in laboratory prepared containers, <br /> and shipped on ice to the laboratory Chain of custody forms will be completed for all samples <br /> delivered to the laboratory Based on the analytical results, the distribution of contaminants in the <br /> groundwater will be qualitatively evaluated as previously described <br /> Consistent with HLA's standard operating procedures, purge water will be collected and stored onsite <br /> in 55-gallon drums Soils from borings will be placed iii 55-gallon drums for storage until laboratory <br /> results are received HLA will advise HSC regarding proper disposal of the soil cuttings <br /> Task 2 - Oil Bunker Investigation <br /> Based on our experience, HLA recommends that HSC attempt to close the bunker in place The cost <br /> of excavation and removal of the concrete bunker would significantly exceed the amount for in-place <br /> closure Excavation of the bunker would require an engineered excavation to protect existing nearby <br /> structures, including the railroad tracks and above ground molasses tanks Based on the above, HLA <br /> will perform the scope of work described below in order to collect the information necessary for in- <br /> place closure of the bunker <br /> The northern end of the bunker has been excavated and exposed The remaining sides of the bunker <br /> are not exposed HLA proposes to collect two soil samples from below the base of the bunker One <br /> sample will be collected from each end of bunker The soil samples will be collected by coring a hole <br /> through the base of the bunker and collecting a soil sample If groundwater is encountered, a <br /> groundwater sample will be collected in lieu of a soil sample The sample will be collected and <br /> handled consistent with the procedures described in Task 2 1 Sampling equipment will be cleaned <br /> with soap and water between samples <br /> Task 3 - Analytical Program <br /> HLA will submit a total of 2 groundwater samples from the monitoring wells and 1 QA/QC <br /> groundwater sample HLA will also submit a total of one soil sample from each of the two sampling <br />