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Langston`s Market 15615 Seventh Street, Lathrop, California Oclobcr 5, 1995 Interim Secondary, ,Vource,Removal& Alonitorirg lVell Replacement Page: 5 1 ' (83 to 101' range) and ilio windy were 4 miles/hour (inph) fromtheorthwest {data from Stockton Municipal Airport) Approximately 5,500 tons of contaminated soil was excavated from the pit and staged next to the excavation at ' ground level Next, the soil was loaded into RFIT, Inc end-dump trucks with a front end loader The uncovered Irticks then drove eight miles to Forward Landfill/ and dumped the load (Appenoix G) Foiward Landfill personnel then formed ' stockpiles with a front-end loader and covered the piles with Visquene The soil was handled at least five times before characterization samples were taken (Figure 8) This repeated aeration may account for the tow analytical results from the first ' sampling event on September 12, 1995 (Table 1 2) A second, deeper sampling I was conducted on September 15, 1995 and did not differ significantly from the first sampling (Table 1 3) Additional contaminated sail used as a ramp for the ' excavator was shipped and sampled on September 29, 1995 (Table 1 4) At the completion of the excavation, a portable analytical laboratory, Monroe J Laboratories, Inc , San Jose, California, conducted soil and water analyses on samples from the walls, floor and groundwater of the excavation ('fables 1 6 & 2 2, Appendices A & B) Analysis of soil samples to the north and west show small amounts of contamination remaining under 50 ppm (Figure 3 & Table 1 6) Excavation was limited to the east and south by roadways and utilities (Figure 3) Remaining contamination in those direction; were less than 100 ppm Engineered backfilling began on September 12, 1995 Both native backfill and imported backfill were tested for compaction (Appendix J) Backfilling and compaction continues and will be completed by October 20, 1995 Measurements of spoilprles and tiuck weight tickets were compared for total cubic yai ds removed from the excavation Overburden calculated at 2,727 c y SpoiIpiles at Forward measured an additional 3,333 c y , for a total bank yardage of 6,060 c _Y Calcuintiona of the c-ccavation yardage was 5,900 c y ! While backfilling was in progress, replacement of the four (4) monitoring wells was conducted 33 Drilling Between September 7.1 to 23, 1999, IN'HF and Frontier Drilling conducted six soil borings and completed four a!, groundwater monitoring weiis (Figure 3) All borings were terminated between 34 and 36'/2 feet b g I after sampling below a clay interval betwecin 27 and 33 feet b g 1 The borings were backfilled with