Laserfiche WebLink
impacted soil has been removed. Since the field test kit has a detection limit of 13 ppm for <br /> diesel, confirmation of removal of diesel below 1 ppm will be performed by the fixed laboratory. <br /> After all impacted soil has been removed and the screening samples result in less than 50 ppm <br /> TPH hydraulic oil, approximately 6 samples will be taken from the bottom of the excavations <br /> and 13 samples will be taken from the sidewalls to be sent to the fixed laboratory. Samples will <br /> be obtained by either driving the sleeve directly into the soil or using a stainless steel trowel <br /> (scoop). The soil will be placed into stainless steel sleeves and sent to the fixed laboratory. The <br /> samples will be analyzed for total petroleum hydrocarbons, diesel and hydraulic oil, by USEPA <br /> Method 8015 modified. The exact sampling locations are described in the Sampling Analysis <br /> Plan, Appendix C, of this work plan. <br /> 3.8 Site Restoration <br /> The excavations will be backfilled with clean fill, some of which may be the excavated soil if <br /> deemed clean based upon the field screening and laboratory analytical results. The excavations <br /> will be backfilled immediately following confirmatory sampling due to the hazards associated <br /> with keeping the excavations open. Even with safety cones and other barriers, an open trench is <br /> always a physical hazard. In addition, the work will be conducted during the rainy season and <br /> the size of the excavations are too large to cover with watertight structures. <br /> Clean import soil will be mixed with the clean excavated soil prior to backfill. The soil will be <br /> placed in eight (8)-inch lifts and compacted to 95% maximum dry density using a sheeps-foot <br /> compactor. Each layer will be properly moistened with water from the onsite fire hydrant. A <br /> compaction engineer will take two compaction tests at 1-foot bgs, one from each excavation. <br /> Rough&Ready Island 20 Tetra Tech, Inc. <br /> Revised Draft Work Plan November 18, 1998 <br />