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Conestoga-Rovers & Associates <br /> STANDARD FIELD PROCEDURES FOR SOIL BORINGS <br /> This document presents standard field methods for drilling and sampling soil borings. These <br /> procedures are designed to comply with Federal, State and local regulatory guidelines. Specific <br /> field procedures are summarized below. <br /> Objectives <br /> Soil samples are collected to characterize subsurface lithology, assess whether the soils exhibit <br /> obvious hydrocarbon or other compound vapor odor or staining, estimate ground water depth and <br /> quality and to submit samples for chemical analysis. <br /> Soil Classification/Logging <br /> All soil samples are classified according to the Unified Soil Classification System by a trained <br /> geologist or engineer working under the supervision of a California Registered Geologist (RG) or <br /> a Certified Engineering Geologist (CEG). The following soil properties are noted for each soil <br /> sample: <br /> • Principal and secondary grain size category (i.e. sand, silt, clay or gravel) <br /> • Approximate percentage of each grain size category, <br /> • Color, <br /> • Approximate water or product saturation percentage, <br /> • Observed odor and/or discoloration, <br /> ■ Other significant observations (i.e. cementation, presence of marker horizons, <br /> mineralogy), and <br /> • Estimated permeability. <br /> Soil Boring and Sampling <br /> Soil borings are typically drilled using hollow-stem augers or hydraulic push technologies. At <br /> least one and one half ft of the soil column is collected for every five ft of drilled depth. <br /> Additional soil samples are collected near the water table and at lithologic changes. Samples are <br /> collected using lined split-barrel or equivalent samplers driven into undisturbed sediments beyond <br /> the bottom of the borehole. The vertical location of each soil sample is determined by measuring <br /> the distance from the middle of the soil sample tube to the end of the drive rod used to advance <br /> the split barrel sampler. All sample depths use the ground surface immediately adjacent to the <br /> boring as a datum. The horizontal location of each boring is measured in the field from an onsite <br /> permanent reference using a measuring wheel or tape measure. <br /> Drilling and sampling equipment is steam-cleaned prior to drilling and between borings to <br /> prevent cross-contamination. Sampling equipment is washed between samples with trisodium <br /> phosphate or an equivalent EPA-approved detergent. <br /> I of 3 <br />