ARCHIVED REPORTS XR0003524 - Laserfiche WebLink

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CAMBRIA 0 Based on the area outlined on Figure 3 and assuming we can dig to a depth of 15 fbg, the estimated volume of soil to be removed is approximately 1,100 cubic yards The lateral limits of excavation may be extended or reduced in the field based on evidence of, or lack of evidence of petroleum hydrocarbons in soil as determined by visual or olfactory observations and organic vapor meter readings Safety concerns for site workers and the public, as well as concerns for undermining existing surface structures may also limit the lateral limits of excavation Well Destruction Well MW-5 is located within the planned area of overexcavation This well will need to be properly destroyed prior to overexcavation activities Cambria will obtain a well destruction permit from EHD for this work and schedule a drilling contractor to perform this work per EHD guidelines At this time we are not planning to reinstall well MW-5 after overexcavation activities are completed After overexcavation activities are completed we will prepare a site conceptual model which will help determine if replacement of well MW-5 is warranted Soil Disposition Excavated soil will be stored on, and covered with, plastic sheeting Soil may also be directly loaded into trucks for immediate offhaulmg Soil will be disposed of at Allied Waste's Forward Landfill (Forward), located in Manteca, California We have discussed this protect with Forward, and they will allow us to use the recent soil assessment data as the profile for soil disposal Soil Sampling Soil samples will be collected at the limits of excavation to document soil conditions Based on the gasoline constituents detected in soil during the June 2004 soil assessment work, soil sample analyses will include TPHg, benzene, toluene, ethylbenzene, and xylenes (BTEX), MTBE, and tertiary butyl alcohol (TBA) The other oxygenates (including ethanol) and lead scavengers were not detected during the June 2004 soil assessment work The only exception to this was three detections of tertiary amyl methyl ether (TAME), but the two highest detections of TAME were found in soil borings within the area of planned overexcavation Dewatering To allow for excavation of soil below the level of groundwater, dewatering activities may need to occur Should dewatering be necessary, existing extraction well RW-IA may be utilized to extract groundwater Other dewatering techniques, including use of vacuum trucks and/or installing a temporary perforated casing within the excavation, may be utilized as necessary Water generated during dewatering activities will be temporarily stored onsite in Baker tanks and then hauled to the Martinez Refinery to be recycled • 0783 4