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1 amec6 ' The proposed excavation area will be marked for clearance of underground utilities and obstructions. The proposed excavation area will then be cleared of underground utilities or other subsurface obstructions by a private utility locating company and by Underground Service Alert. Although no utilities are known to exist within the excavation boundaries, unidentified utilities 1 may exist at the Site. Any active utilities encountered during excavation activities will be protected or temporarily re-routed. Inactive utilities will be cut and capped, and/or demolished in accordance with City of Tracy requirements. As described below, the "fill mound" soil on-site is proposed as the backfill source for the excavation. Samples of the fill mound will be taken and analyzed by the Proctor test American Society for Testing and Materials ([ASTM] D698 - Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort) to establish compaction requirements for backfilling with this soil. ' 5.2.2 Excavation of Affected Soil AMEC proposes that Site soil exceeding the commercial/industrial screening criteria in the ' vicinity of and including the sample locations GMX-09, GMX-25, and GMX-31 be excavated. The affected soil will be removed using a backhoe and/or excavator, starting near the area of sample locations GMX-09, GMX-25, and GMX-31, and extending outwards. Visibly-affected soil will be removed; the estimated maximum excavation limits are shown on Figure 6 based on previous sampling data. The maximum volume of soil to be excavated, assuming excavation to a depth of 6 ft bgs, is approximately 1,350 yd3. Soil on the excavation floor and ' sidewalis will be screened with a photoionization detector, and by visual inspection to assess whether additional excavation is needed. If field screening identifies impacted soil on the excavation floor or sidewalls, the vertical and/or horizontal limits of the excavation will be extended. If field screening does not identify impacted soil, confirmation soil samples will be collected for laboratory analysis. Confirmation soil sample collection and analysis is discussed ' further below. All excavation work will be performed in accordance with California Division of Occupational Safety and Health regulations, including installation of protective systems to prevent excavation cave-ins, where required. For the purposes of this work plan we have assumed sidewall slopes of 1:1. If visibly-affected soil is found to extend towards the Site boundary, adequate shoring may be required to excavate up to the Site boundary. The excavation will ' not extend beyond the Site boundary into the greenbelt area. ' AMEC Geomatrix, Inc. I:\Doc_Safe\6000s\6628.001\3000 REPORTS\Excavation Work Plan-8.12.08\1 Text,cover and slips\Text.doc 6