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Shell OilCompany ORO April 19, 1995 (9447-8617) ' 3.3 Over-Excavahon and Addihonal Sampling ' Based on the initial excavation sampling results, some over-excavation was requested by Eric Travena Additional over-excavation occurred below the former 6,000-gallon USTs (Tanks 1 and 2 on Figure 3) On December 8, 1994, three additional soil samples were collected from this area at a depth of 21 feet bgs (TP-1/21, TP-2/21, and TP-3/21) Also, two soil samples were ' collected from the pit sidewalls at a depth of 17 feet bgs (ES-2SSW/17 and EN-2NSW/17) The above soil samples were collected per the direction of Eric Travena of the SJCDEH ' On December 14, 1994, Golden West excavated the soils around and below the canopy and the pump islands to a depth of five feet bgs Six samples were collected from this excavated area (T7-T12) per the directions of Steve Sasson of the SJCDEH Over-excavation sampling ' locations are shown on Figure 3 Analytical results are summarized in Table 2 Four additional samples were collected from the 100 cubic yard soil stockpile generated from this excavation and composited to two samples (OSP4A,B and OSP5A,B) ' On December 22, 1994, Fugro personnel collected four soil samples from a 100 cubic yard soil stockpile generated by extra trenching for new electrical lines (ETSPIA, ETSPIB, ' ETSP2A, and ETSP2B) Steve Sasson also directed the Fugro geologist to collect one soil sample along the southeast corner of the former pump island excavation pit (ETI) After installing the new USTs, the excavation was backfilled to grade with clean pea gravel 3.4 Stockpiled Soil Stockpile sampling locations are shown on Figure 4 All excavated soils were stockpiled on plastic sheeting on-site, prior to characterization and disposal Generally, two discrete soil samples were collected per approximately 100 cubic yards of stockpiled soil and composited in the laboratory prior to analysis Based on the hauling company's manifests, approximately 1,100 cubic yards of soil were generated during the removal of the USTs and subsequent over-excavation work On December 17, 1994, approximately 950 cubic yards of stockpiled soil were transported to Forward, Inc 's landfill located in Manteca, California On January 12, 1995, an additional 150 cubic yards of soil were transported to a Sacramento County landfill All soil was transported by Manley and Sons Trucking, Inc of Sacramento, CA The soil disposal documentation is in Appendix D Unauthorized release forms are included as Apendix E 4.0 CONCLUSION Approximately 1,100 cubic yards of soil were removed from the former tank basin and piping trenches The soil was transported to and disposed at Forward, Inc landfill and the Sacramento County landfill The former tank pit was vertically excavated to a depth of 21 feet bgs, the maximum extendable depth of the backhoe Two 15,000-gallon double-walled fiberglass tanks were installed in the excavated tank pit and backfilled with clean pea gravel Based on confirmation sampling, it is the opinion of Fugro and Shell that no further action is warranted at the site 94478617 BRP -4-