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• CEC ® R k., Mr. Mike Infurna November 21, 2005 Page 2 5.^rvr Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" ;. guidelines (CCR Title 8, Section 5192), SECOR will prepare a Site-Specific Health and Safety Plan prior to the commencement of fieldwork. The Site-Specific Health and Safety Plan will be reviewed by the field staff and contractors before beginning field operations at ^ , the site. 3i'?a u Permitting. Groundwater monitoring well installation permits and soil boring permits will bei. 9 p 9 p . ,. obtained from SJCEHD prior to initiating work. . Deep Well Installation Option One. One groundwater monitoring well will be installed at the proposed location shown on Figure 1. Groundwater is anticipated to be encountered at approximately 30 feet below ground surface (bgs). The proposed first option for installation of the soil boring is mud rotary drilling using a 10-inch diameter drilling bit. Mud is 7 `fF advanced through the drilling rod and bit in order to stabilize borehole walls and seal off �Y �,a shallow water-bearing zones. Upon completion of drilling, a 4-inch diameter groundwater monitoring well will be installed in the boring. The casing size is selected due to the proposed well depth, since 2-inch diameter casing typically bends/distorts at greater depths, which makes gauging/sampling difficult to not feasible. The well will be screened with 4-inch diameter, flush-threaded, Schedule 80 PVC casing ° with 0.020-inch factory-slotted screen. The well will be installed to 180 feet bgs. This depth is proposed based on existing site data indicating dissolved gasoline components are present at 120 feet bgs. Approximately 20 feet of screen is proposed for the bottom of the boring. A grade of sand appropriate to the screen size will be tremmied into annular space across the entire screened interval, and will extend approximately two foot above the top of the screen for the wells. A bentonite pellet and #60 sand mix seal will extend two to four feet above the sand pack. The monitoring wells will be completed with neat cement from the bentonite seal to the ground surface. Grout will be tremmied within the annular space between the mud and the PVC pipe. The well casing will be topped with a locking cap. The well head will be contained in a watertight monument well box. Proposed well construction details are included in Table 1. d? Deep Well Installation Option Two. One sonic boring will be advanced to approximately 180 feet below ground surface (bgs) to assess soil lithology below 120 feet bgs. Continuous soil cores will be collected from 120 feet bgs to 180 feet bgs and logged by SECOR field Staff under the direction of a California Registered Professional Geologist. A ? conductor casing will be used to seal off shallower water-bearing zones during well construction. Upon completion of drilling, a 4-inch diameter groundwater monitoring well will > be installed in the boring. The well will be screened with 4-inch diameter, flush-threaded, ` Schedule 80 PVC casing with 0.020-inch factory-slotted screen. The well will be installed to 180 feet bgs, and 20 feet of screen is proposed to be placed in the bottom of the boring. A ,s.,4f: grade of sand appropriate to the screen size will be placed into annular space across the r,.T entire screened interval, and will extend approximately two foot above the top of the screen •} for the wells. A bentonite pellet seal will extend two to four feet above the sand pack. Thet p conocoPhillipsl44091work plansNVP For Well Installation 11-05.doc