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- �. RL excavation and that the S:1LHD be notified in time to with ss all sampIing. After waiting until February, 198? , excavation was com-nenced without DHS approval , although they were notified that such activities were going to commence. The Dec. 9 , 1988 proposal was never approved by the DHS, presumeably owing to the fact that "%Ve have found the plan inadequate and are discontinuing our review as the work plan does riot specifically address or define the lateral and vertical extent of soil and/or groundwater contamina- tion." , quoted from Appendix A- 11 , May, 1959. It would seem that a proposed additional 3,335 cu. ft . of soil removal at the site of contamination, which encompassed an area from the surface to the groundwater vertically and horizontally to surrounding moni- toring wells, which had tested clean, could be presumed to remove all contaminated material , not just define extent . However , the proposal did not include the use of either a registerd geologist or engineer as is required by County and Tri -Regional guidelines. Based on the above premise, that all contaminated soil could be removed, the DHS was informed that owing to many considerations, including safety, protection of the groundwater from infiltration through the open pit that still had contaminated soil in it and time considerations, JTO was going ahead with excavation. 'During February, -1989 the pit was dug to its approximate size today, about 160 ' to 180' across at the outer perimeter and 45 ' deep; it was hater refilled to about 30 ' , its current depth (Figure 4) . Access ramps and erosion gulleys extend farther out. The original dug depth of about 45' below ground level (g. l . ) , put the bottom of the pit well into the ground water table; which had been found at about -38 to -40 ft g. l . by GTI . (Apendix A-7) . During exca- vation, he sides were cut with lifts ( terraces) to help prevent caving of the sidewalls, leaving the bottom of the pit about 10' to 60' smaller than the top periphery. The total spoil removed now totaled about 15,000 cu. yds. All clean spoil was placed on plastic sheeting over asphalt in Pile # 3, contaminated spoil was placed either in Pile 11 1 or Pile # 2 , also over plastic sheeting lving either on asphalt paving or concrete slabs. Segregation was achieved by a combination of visual inspection and odor. JTO re- ported that water did not immediately enter The hole when digging below the -3S' groundwater level . A clayey sand was penetrated at about -40 ' g. l . . at the south end of the excavation and ground- vater entered the hole thereafter. This clayey sand was logged in the GTI boring If 5. Water gradually filled the excavation to a depth of about -35' . 10' deep at the south end of the excavation (See Appendix 14 map) . The level of the water was measured by a surveyor and 3TO from the top of the asphalt surface at the top of tie entrance ramp, about-5G '-_aboC•e mean sea !e�`el : - i5-ivau ------ ------ ------- put the standing water level about 5 ' higher than either County Flood Controlrecords (Fig. 5 ) , or levels measured in the ;monitoring wells . The -35' b . l . elevation was taken in April . 1989, at' a time when there had not been any recent rainfall . The 4