WORK PLANS FILE 2 - Laserfiche WebLink

Home Browse Search

_ 1 _ 1 T San Joaquin County Environmental Health Department RE: Beneto, Inc., 749 E. Charter Way, Stockton, CA Page 3 of 4 will be changed after drilling out the shoe and will be kept in an overbalanced condition to minimize fluid entry and to control possible heaving sands. To complete the well, 2-inch diameter PVC casing equipped with centralizers and 10 feet of 0. 020 slot pre-packed screen will be set from the bottom of the boring to grade. The screened interval will be from approximately 130440 feet bgs. Approximately 2 additional feet of filter pack will be placed above the pre-packed screen. The remaining annulus will be completed with 2 feet of bentonite overlain by neat cement grout to the surface, emplaced with a tremie system. At the surface, the well will be fitted with a locking cap and watertight, traffic rated well box. A well construction diagram for MW18C is shown on Figure 4. Due to the mud rotary drilling method, we do not expect to collect undisturbed soil samples for laboratory analysis. The lithology of the soil units penetrated was determined by the CPT log of boring 134 (Attachment 1 ). Drill cuttings and drilling mud will be stored in lined roll-off bins pending disposal. Water generated from equipment decontamination, well development; and sampling will be contained in labeled DOT approved drums. All waste will be stored on site pending laboratory results and the development of disposal options. Surveying, Well Development and Groundwater Sampling and Analysis The elevation of the casing collar of the new wells will be surveyed to a vertical accuracy of 0.01 feet and the latitude and longitude of the well will be established to an accuracy of one meter or less. A minimum of 48 hrs after well completion, an experienced field technician will measure static depth to water and then develop the well by pumping and surging until turbidity is minimized and measurements of pH, temperature, and electrical conductivity have stabilized. A minimum of ten casing volumes will be purged from the well. J d Subsequent to well development, groundwater samples will be collected after water levels have recharged to at least 80% of the static levels. Water samples will be placed in appropriate containers, labeled and placed in an ice chest at a temperature of approximately 4 degrees Centigrade for shipment to a state-certified laboratory under chain of custody protocol. Analysis will consist of total petroleum hydrocarbons as gasoline (TPHg) by EPA Method 8015M; benzene, toluene, ethylbenzene and xylenes (BTEX) by EPA Method 802113; and oxygenated gasoline additives, 1 ;2-dichloroethane (1 ,2-DCA) and ethylene dibromide (EDB) by EPA Method 8260B. Protocols and Permitting All fieldwork will be conducted in accordance with our Field Procedures Plan and site-specific Health and Safety Plan. A drilling permit application and associated fees will be submitted following approval of this workplan. U:\L&P\Beneto\WKPLAN_deepwells.doc