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Report—Monitor Well Installation and Sampling
<br /> New Jerusalem School
<br /> February 26, 1999
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<br /> 3. FIELD AND ANALYTICAL METHODOLOGY
<br /> L' Three monitor wells (MW-1, MW-2, and MW-3) were installed at the site on December 21, 1998, using
<br /> hollow stem auger drilling techniques. This section describes the site preparation, drilling procedures,
<br /> monitor well construction, surveying, development, sampling, and laboratory analyses of the soil and
<br /> groundwater samples.
<br /> 3.1 SITE PREPARATION
<br /> Prior to initiating the fieldwork, a monitor well drilling permit was obtained from the PHS/EHD. The
<br /> proposed drilling locations were marked with white paint and an underground utilities locating service
<br /> (Underground Service Alert) was notified 72 hours in advance of the fieldwork to locate and identify
<br /> underground utilities in and near the work area. A site specific Heath and Safety Plan was discussed
<br /> with, and signed by all field personnel at a tailgate meeting prior to commencement of the field work.
<br /> 3.2 DRILLING PROCEDURES
<br /> The groundwater monitor wells were installed by Spectrum Exploration, Inc. of Stockton, California (C-
<br /> 57 license No. 512268). A Condor geologist was on site to supervise the drilling, soil sampling, and
<br /> monitor well installation. The monitor well locations are shown in Figure 2, Appendix A.
<br /> The monitor well boreholes were drilled using an 825-inch diameter, continuous flight, hollow stem
<br /> ` auger. All down-hole equipment was steam cleaned prior to use. The soil sampling equipment (i.e.,
<br /> split-spoon) was cleaned prior to collecting each sample. The cleaning procedures consisted of washing
<br /> the sampling spoon in a solution of laboratory-grade, non-phosphate detergent and hydrocarbon-free
<br /> water, and double rinsing with hydrocarbon-free water.
<br /> The boreholes for monitor wells MW-1, MW-2, and MW-3 were drilled to depths of approximately 23,
<br /> 60 25, and 25 feet bgs, respectively. Groundwater was encountered at approximately ten feet bgs in each
<br /> boring. Soil samples were collected from various depths in each boring. A description of the site
<br /> geology is included in Section 4. of this report.
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<br /> Soil samples were collected with a California-modified split-spoon sampler fitted with three clean, brass
<br /> liners_ The split-spoon sampler was driven ahead of the lead auger using a rotating drum ("cathead") and
<br /> pulley system to raise and drop a 140-pound safety hammer through an average fall of 30 inches to drive
<br /> the soil sampler. The uppermost liner was discarded. The middle sample liner was used for geological
<br /> logging and for field screening using a photoionization detector (PID) and the bottommost liner was
<br /> prepared, as described below, for possible shipment to the laboratory. The soil samples were logged
<br /> according to the Unified Soil Classification System. Drilling logs were prepared containing field
<br /> observations including soil type, estimated moisture content, presence of staining or odor, and field PID
<br /> �.. measurements. The drilling logs are included in Appendix B of this report.
<br /> All soil samples collected for laboratory analyses were retained, undisturbed, in the brass liners. The
<br /> liners were sealed at the ends with Teflon sheeting, capped, wrapped with duct tape, and labeled. The
<br /> samples were stored in a cooler chilled with ice and delivered, under chain-of-custody procedures, to
<br /> GeoAnalytical Laboratories in Modesto, California on the day of collection.
<br /> The soil cuttings from the borings and steam cleaning effluent were containerized in 55-gallon drums,
<br /> sealed, labeled, and left on site pending laboratory analyses. Disposal of hazardous materials, if any, is
<br /> the responsibility of the property owner.
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<br /> CONDOR
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