Laserfiche WebLink
ATTACHMENT A <br /> WELL INSTALLATION FIELD AND LABORATORY PROCEDURES <br /> AND BORING LOGS <br /> Exploratory Drilling <br /> The soil borings for well installation were drilled using 8-inch hollow-stem auger drilling <br /> equipment to depths of 43.5 and 80 feet below ground surface (bgs) for Wells MW-8 and <br /> MW-9, respectively. Borings were logged by a Pacific Environmental Group, Inc. geologist <br /> using the Unified Soil Classification System and standard geologic techniques. Soil samples <br /> for logging were collected at 5-foot depth intervals using a California-modified split-spoon <br /> sampler. The sampler was driven a maximum of 18 inches using a 140-pound hammer with <br /> a 30-inch drop. All soil samples for chemical analysis were retained in brass liners, capped <br /> with Teflon squares and plastic end caps, and sealed in clean zip-lock bags. The samples <br /> were placed on ice for transport to the laboratory accompanied by chain-of-custody docu- <br /> mentation. All down-hole drilling and sampling equipment was steam-cleaned following the <br /> completion of the soil boring. Down-hole sampling equipment was washed in a tri-sodium <br /> phosphate or alconox solution between samples. <br /> Groundwater Monitoring Well Installation <br /> Two borings were converted to groundwater monitoring wells by installing 2-inch diameter, <br /> flush-threaded, Schedule 40 PVC casing with 0.020-inch factory-slotted screen. Approxi- <br /> mately 10 to 15 feet of screen was placed in the bottom of the boring. An RMC 2/12 sand <br /> pack, or equivalent, was placed in the annular space across the entire screened interval, and <br /> will extend approximately 2 feet above the top of the screen for the well. A 2 to 3 foot <br /> bentonite transition seal was placed atop the sand pack, and a Portland cement seal will <br /> extend from the bentonite transition seal to the ground surface. The groundwater monitoring <br /> wells were developed after completion. <br /> Organic Vapor Procedures <br /> Soil samples collected at 5-foot depth intervals during drilling were analyzed in the field for <br /> ionizable organic compounds using a flame-ionization detector (FID) or a photo-ionization <br /> 920-078.IA/SOLGWRPT A-1 November 24, 1997 <br />