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From the Beta work, indications are that groundwater is not encountered until approximately 43 feet. Site investigation suggests contamination vertically stops at or above the confining clay layer at approximately 29 feet. Therefore we feel that groundwater is unaffected. 5.0 Remediation 5.1 General 5.1.1 On October 2, 1995 San Joaquin County accepted the bucket auger approach/plan for soils removal at the site. Viking Drillers, Inc. of west Sacramento was contacted and the project was scheduled for October 23, 1995. 5.2 Excavation With Bucket Auger 5.2.1 Procedure--Observation log 10/24/95 1. The cap slab was cut with a concrete saw, at the outer edge and at several internal, locations. The entire slab, approximately twelve feet by six feet was removed. 2. Backfill material, (pea gravel), was removed to a depth of approximately ten feet from the ground surface with a backhoe. The hole perimeter was protected with steel plates. 3. A 36" casing was installed in the Northwest comer, and driven to a depth of approximately fifteen feet. 4. The drill rig was positioned and augering began. As residual pea gravel was removed more pea gravel began to seep into the hole. It became apparent that the casing was not completely seated. 5. The auger was removed and the casing re-seated. This process was repeated until the casing was firmly seated at approximately 15 to 16 feet. 6. Due to the difficulty with seating the casing,the first sample was taken at 18 feet. An OVM reading was performed on the sample, it was non-detect. The analytical results from the soil sample were also non-detect. 7. The hole was completed to a depth of 28 feet and a bottom hole confirmation sample secured. No hydrocarbon odor was detected at any point in the excavation of the first hole, and OVM readings were non-detect. The analytical results from the soil sample were also non-detect. 8. Excavated native soils were temporarily stockpiled on-site pending analytical testing results. 9. A second casing was placed next to the first, at approximately the Southwest comer. Placement of this casing was unsuccessful and augering resulted in a small breach in the sidewall of the first boring, causing pea gravel from the adjacent area to enter the first hole. 10. Excavation was halted. Pea gravel remaining across the bottom of the excavation was approximately two feet deep. Control Density Fill, (CDF),was placed into the first hole and across the bottom of the excavation into the pea gravel. The remaining pea gravel was then stabilized and the casings were removed. The CDF was allowed to cure overnight. r` Page 5