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i <br /> Mr. Tom Juano <br /> Herrick Corporation <br /> March 15, 1993 <br /> Page 6 <br /> limits of SJCPHS. Analysis of Sample #5 reported non-detect <br /> concentrations of TPH-d and .008 ppm of Benzene. Concentrations <br /> of Benzene need to be below detection limits in order to obtain <br /> closure from SJCPHS. Analysis of the stockpile samples reported <br /> low levels of BTEX and a range of TPH-d between 48 ppm and 210 ppm. <br /> DECON remobilized and excavated an additional 40 to 60 cubic yards <br /> of soil from the location of Sample #5. One sample was collected <br /> and witnessed by a representative from SJCPHS. The sample was <br /> analyzed for TPH-d, TPH-g, and BTEX on a 24-hour turnaround time. <br /> Analytical results reported no detectable concentrations for all <br /> constituents (Appendix F) . Permission was granted by SJCPHS to <br /> backfill the excavation. <br /> Backfilling <br /> The excavation was backfilled with self--compacting 1/4" x 1/2" pea <br /> gravel imported from Granite Construction. The excavation was <br /> filled with 614 .90 tons` of pea gravel to a depth of 1 foot below <br /> ground surface. Approximately 75 of the 400 cubic .1 yards of <br /> stockpiled soil contained concentrations of TPH-d below 100 ppm and <br /> concentrations of BTEX below detection limits. This is considered <br /> acceptable for use as backfill by SJCPHS. The 75 cubic yards of <br /> soil capped the pea gravel and filled the remaining 1-foot space <br /> left in the excavation. A geo-textile fabric was placed between <br /> the soil and the pea gravel to prevent any future settling of the <br /> soil into the pea gravel. The one foot lift of soil was rolled <br /> with a vibrating sheepsfoot compactor and graded to match the <br /> I <br />