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16 <br /> encountered. Soil samples will be collected using a 5-centimeter (2-inch) diameter sampler lined <br /> with a 1.3-meter (4-foot) long acetate sleeve. Groundwater samples will be collected from each <br /> boring using one or more of the methods described in Section 4.3.3. Drilling and sampling <br /> procedures are presented in Appendix A. <br /> Following sample collection, the borings will be backfilled with bentonite cement grout from the <br /> bottom of the borehole to ground surface. The surface material will be repaired with cold patch <br /> asphalt or concrete where applicable. Drill cuttings will be placed into a 208-liter (55-gallon) <br /> United Nations-approved drum. <br /> All drilling and sampling equipment will be washed prior to use. In addition, to minimize <br /> cross-contamination between borings, all appropriate downhole drilling and sampling equipment <br /> will be washed between borings. Decontamination water will be placed into a 208-liter <br /> (55-gallon)United Nations-approved drum. <br /> The horizontal and vertical locations of the borings will be established using a Trimble GPS <br /> Pathfindefrm Pro XRS global positioning system (GPS). The GPS utilizes a GPS receiver and <br /> MSK radio beacon differential receiver. The GPS is reported to have sub-meter accuracy for <br /> horizontal location of the borings. The vertical accuracy is reported to be two to five times that <br /> of the horizontal accuracy. The GPS data will be downloaded in the office with Trimble <br /> software to provide differential corrections to the coordinates. <br /> 4.3.3 Groundwater Grab Sample Collection <br /> Groundwater grab samples will be collected from the soil boring locations. The groundwater <br /> samples will be collected from either well casing inserted into each boring or HydroPunch-type <br /> groundwater sampling equipment. The well casing will consist of 2.5-centimeter (1-inch) <br /> diameter, Schedule 40, flush-threaded, 0.05-centimeter (0.020-inch), machine-slotted polyvinyl <br /> chloride (PVC) well screen. The soil borings may be advanced to greater depths depending on <br /> the groundwater conditions. If free product is encountered, product thickness will be verified <br /> using a disposable bailer. Up to three methods may be used for groundwater collection and these <br /> include the following. <br /> • Dedicated Teflon tubing with a single-ball, stainless steel check valve; or <br /> • A new disposable polyethylene or Teflon bailer, or stainless steel bailer; or <br /> • A peristaltic pump and new dedicated Teflon tubing. <br /> SAGDP-N:4ancfpl\Projecrs\83\834760,wkpin&hsp\SR 120 wp.doc 4-3 <br /> W5N2 <br />