SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

SEP-15-2003 69 : 17 AM PP =R, CEG 408 7396 P. 03 Well and Probe Installation Procedures The vapor extraction wells and vapor monitoring probes will be installed using hollowatem drilling methods. Each well or probe will be installed in a borehole to the depth shown. The wells will be installed under approved PHS E:HO permits and the work will be supervised by a registered geologist, The site has been logged and the site stratigraphy has been mapped. Sample lithologic logging will be performed to verify strata contacts to install the well slots at the desired depth interval. The boreholes will be advanced by drilling to the desired depth with pre-cleaned hollowstem augers. Augers, sampling tools and rods will be cleaned after each borehole and prior to leaving the site. Soil logging for contact verification will use the Unified Soil Classification System (USCS) using a split-spoon soil sampler advaneed at the desired depth. A geologist will leg the soil and retain samples as neekled. If 8011 samples are retained, they will be collected in clean brass liners completely driven to completely fill the liners in the sampler drive. The soil sample will be taken from the split-spoon, sealed with Teflon paper or foil, capped with plastic endplugs, logged onto a chain-of-custody form and packed of crashed ice for shipment of the laboratory. Each wail or probe will be constructed in the appropriate borehole The wells will use Schedule 80 PVC casing as shown. The casing will use threaded joints and glues will not be used. The casing will be cut to the length and threaded together and lowered into the hollowsfem augers. The slotted intervals will use 0.020 slots machine out at the factory. Once the casing is set, an aquarium sand pack will be placed around the casing annular space using the hollowstem sugar as a tfemie pipe. The sand pack will be placed to a point about 2-feet above the slotted interval. A bentonite Olay spacer will be placed atop the sand pack and hydrated prior to the cement grout placement to prevent grout invasion into the sand pack. A cement ground seal will then be placed atop the bentonite clay and raised to the surface from the bottom to the top of each borehole using the hollowstem augers as a tremis pipe. A traffic rated locking well vault box will complete each extraction well head and vapor probe access, The engineer will modify the box as needed to set the vapor sampling ports, magnsholix gauges and other equipment as needed for the vapor test and probe measurements and/or for further vapor extraction from the wells. Vapor Extractlon Well and vapor Probe specifications f'roj. No.:4233-3 Stafanos Oaskrlins Dimensions as shown 1419 Charter Way Dete: Sept.2003 Wright Environmental Sen4ces, Inc. Gtockton,CA Tracy, CA Figure 1