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APPENDIX A. <br />Management and Disposal Plan for Contaminated Soils in the <br />• Northern Portion of Subarea 3. <br />1.0 Management of Contaminated Soils. <br />Contaminated soils have been discovered in the northern portions of Phase 1 and <br />Phase 2 mining areas, generally north of Evaporation Pond I3o. 9. Contaminated <br />overburden will be removed to enable mining of the underlying gravel and hauled <br />firstly to the Corrective Action Management Unit (CAMI~ and secondly, if <br />required, to the acid sludge impoundments located north of the mining permit azea <br />for land farming treatment. The overburden will be tested on site using a portable <br />TPH meter to detect the presence of hydrocarbon contamination. All soils <br />yielding 500 ppm or greater TPH will be flagged for removal to the farming area. <br />Grab soil samples for laboratory analysis for organic compounds and metals may <br />also be required. At the farming areas, the soil will be treated in accordance with <br />the CAMU plan or a similar plan to 6e developed form the former acid sludge <br />impoundments. <br />Tt is not expected that any stockpiling of soil will be necessary outside the land <br />farm treatment areas identified above. However, in the event temporary <br />stockpiling of addition contaminated soil is needed, the stockpile will have the <br />following features:However, in the event that it becomes necessary to remove <br />contaminated overburden in this area to enable mining of the underlying gravel, <br />the contaminated material will be moved and stockpiled north of the road. Any <br />stockpile will be involve the following features: <br />1.1 Water Control & Management. A system of berms surrounding the <br />stockpile will be constructed to contain run-on/run-off from a 25-yeaz, 24 <br />hour storm event of approximately 2.1 inches of precipitation. Berms will <br />be at least two feet above grade and constructed of clean soil material <br />from the Refinery site. <br />1.2 Dust and Odor control. Dust control will be achieved mostly by the <br />oil mixture in the soils. If necessary, this will be augmented by spraying <br />the stockpile with water, or covering the stockpile with impervious plastic <br />sheeting. This will also be the primary method of odor containment. <br />2.0 Disposal of Stockpiled Contaminated Soils. <br />Within a maximum of four yeazs of the commencement of stockpiling, provided <br />the soils exhibit suitable chemical characteristics, the material will be treated in <br />one of the following ways: <br /> <br />75 <br />