ARCHIVED REPORTS XR0008714 - Laserfiche WebLink

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N../Corporation October 28, 1999 A Member of The IT Croup Page 2 encountered. The piping was removed and soil samples were collected at the direction of Mr. Michael Infurna of SJCEHD. Additional excavation and sampling was completed on April 15, 1999 to remove the unidentified piping discovered on April 8, 1999. Over-excavation in the southern portion of the site was terminated to protect the structural integrity of the station canopy supports. Following removal of the former station canopy, canopy footings and kiosk, additional over-excavation excavation was completed on June 1 and 2, 1999. An additional 960 tons of soil were removed to a maximum depth of 31 feet bgs. Over-excavation was terminated when, the structural integrity of the sidewalk was endangered and groundwater was encountered. Groundwater was encountered during additional over-excavation activities at a depth of approximately 31 feet bgs. One water grab sample was collected from the excavation. The grab water sample contained elevated TPH-g and BTEX concentrations. PROPOSED SCOPE OF WORK As stated previously, this investigation is being performed in response to the August 23, 1999 SJCEHD letter requesting further site characterization at the subject site. The scope of work proposed for this investigation will include the installation of four monitoring wells to delineate the lateral and vertical extent of hydrocarbons in the soil and groundwater. Proposed monitoring well locations are based upon an anticipated east to northeast groundwater gradient and are shown in Figure 1. As required by the Occupational Health and Safety Administration (OSHA) Standard "Hazardous Waste Operations and Emergency Response" guidelines (29 CFR 1910.120), and by California Occupational Health and Safety Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CCR Title 8, Section 5192), IT has prepared a Site-Specific Health and Safety Plan (SSP). Prior to the commencement of fieldwork the SSP will be updated with appropriate field personal and subcontractor information. The field staff and contractors will review the Site-Specific Health and Safety Plan before beginning field operations at the site. A draft SSP has been included in Attachment A. The specific scope of work is discussed below: • Monitoring Well Installation. Four proposed groundwater monitoring wells (MW-1 through MW-4) will be installed at the general locations shown on Figure 1. The proposed wells will be installed 15 feet below the current water level and will be screened from 5 feet above. The total depth of each well will be approximately 45 feet bgs. Anticipated depth to water is approximately 30 feet bgs. If this is a localized perched zone, well depth will be greater. All work will be done in accordance with stipulations of permits obtained from the SJCEHD. 911-011.1 S/0102/workplan