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Th <br /> FAATELY <br /> TASK 4 - DRILL ONE SOIL BORING TOAPPR�EXTRACTION EEWIIIJBGS <br /> IN -THE <br /> CONSTRUCTA GROUNDWATER <br /> BORING <br /> ASE will drill one soil boring to approximately 18-feet bas within 10-feet <br /> of monitoring well MW-2 using a drill rig equipped with 12-inch diameter <br /> follow-stem augers (Figure 3). This well will be used as an extraction well <br /> during the pumping test to be conducted at the site. <br /> The drilling will be directed by a qualified ASE geologist. Undisturbed soil <br /> samples will be collected at least every 5-feet for subsurface <br /> hydrogeologic description and possible chemical analysis. The samples <br /> will be described by the geologist according to the USCS. The samples will <br /> be collected in brass tubes using a split-barrel drive sampler advanced <br /> ahead of the auger tip by successive blows from a 140-1b. hammer <br /> dropped 30-inches. Each sample will be immediately removed from the <br /> sampler, trimmed, sealed with Teflon tape and plastic caps, secured with <br /> duct tape, labeled with the site location, sample designation, date a n d <br /> time the sample was collected, and the initials of the person collecting the <br /> sample. The samples will be placed into an ice chest containing wet i c e <br /> for delivery under chain of custody to a CAL-EPA certified analytical <br /> laboratory. <br /> +� Soil from the remaining tubes not sealed for analysis will be removed for <br /> hydrogeologic description and will be screened for volatile compounds <br /> with an OVM. The soil will be screened by emptying soil from one of the <br /> tubes into a plastic bag. The bag will be sealed and placed in the sun f o r <br /> approximately 10 minutes. After the hydrocarbons have been allowed to <br /> volatilize, the OVM will measure the vapor through a small hole punched <br /> in the bag. These OVM readings will be used as a screening tool only since <br /> these procedures are not as rigorous as those used in an analytical <br /> laboratory. <br /> All sampling equipment will be cleaned in buckets with brushes and TSP or <br /> Alconox solution, then rinsed twice with tap water. Rinsates will be <br /> contained on-site in 55-gallon steel drums until off-site disposal can b e <br /> arranged. <br /> This well will be constructed within the hollow-stem augers using 6-inch <br /> diameter, flush-threaded, schedule 40, 0.020-inch slotted PVC well screen <br /> and blank casing. This well will be screened to allow for pumping from <br /> err the first water-bearing zone encountered. Based on the boring logs and <br /> depth to groundwater (6.5-feet bgs) during the previous drilling at this <br /> 574 West Grand Line Road, Tracy, CA Workplan — April 2001 <br /> -7- <br />