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Slurry Wall Design Report <br /> Loloff Pit <br /> 5/24/2016 <br /> Page 2 of 16 <br /> 2 FIELD AND LABORATORY INVESTIGATIONS <br /> 2.1 Brierley Investigation <br /> Brierley performed subsurface investigations from January 18, 2016 to January 28, 2016. <br /> Drilling the test borings was subcontracted to Dakota Drilling from Denver, Colorado. The <br /> borings were observed and logged by Brierley staff. The subsurface conditions revealed by the <br /> field investigation are discussed in Section 3, Subsurface Conditions. Geotechnical laboratory <br /> testing was performed on selected samples. The borings were spaced approximately every 325 <br /> to 550 feet along the slurry wall alignment. Figure 2 presents the locations of the borings. <br /> 2.1.1 Geotechnical Exploratory Borings <br /> 13 exploratory borings were drilled to evaluate general subsurface conditions and to obtain <br /> samples to aid in the determination of engineering properties of the soil and bedrock along the <br /> entire alignment. The exploration program is summarized in Table II. Borings were drilled using <br /> a CME 55 drill mounted on a truck platform. The borings were advanced through the alluvium <br /> and 1.5 to 15 feet into bedrock using hollow stem auger and NQ core barrel methods. Alluvium <br /> was sampled and standard penetration tests were performed in increments of 10 to 15 feet. <br /> Bedrock was sampled and standard penetration tests were performed in increments of 2.5 feet. <br /> Samples of coarse alluvium, consisting of sand and gravel, and fine alluvium, consisting of <br /> overburden and clay (mud) lenses were collected for laboratory analysis from each boring. Four <br /> borings included at least 10 ft of rock coring with two intervals of insitu permeability (packer) <br /> testing per hole. <br /> Modified California Barrel (2-inch I.D., 2.5-inch O.D.) and Standard split-spoon barrel (1-3/8-inch <br /> I.D., 2-inch O.D.) samples were collected in general accordance with ASTM D 3550 and ASTM <br /> D 1586. The modified California barrel sampler is typically used to obtain intact cohesive soil <br /> samples that are well suited for laboratory tests. The penetration values reported on the test <br /> boring reports are the number of blows of a 140-lb hammer falling 30 inches, recorded in 6-inch <br /> intervals for 12 or 18 inches of sampler penetration (Modified California or Standard Penetration <br /> Test respectively). The actual number of blows is reported. Where three 6-inch intervals are <br /> reported, the number of blows for the initial 6 inches is ignored. The Modified California Sampler <br /> Penetration values have not been converted to Standard Penetration N-values. <br /> Test boring reports are included in Appendix A. Descriptions and visual classifications of rock <br /> and soil strata samples were recorded on test boring reports during drilling. Soil descriptions are <br /> preceded by the soil classification, which is in accordance with the ASTM D 2487 or ASTM D <br /> 2488 Soil Classification System. The completed boring reports are provided in Appendix A <br /> along with an explanatory sheet defining the terms used on the reports. Sampling information, <br /> laboratory results, and other pertinent field data and observations are also included on the <br /> reports. Summaries of laboratory results are presented in Appendix B. <br /> 2.1.2 Laboratory Testing <br /> To aid in classifying and determining general soil, rock, slurry and backfill characteristics, select <br /> laboratory tests were performed on representative samples; test method references are shown <br /> in the following table: <br /> BRIERLEY <br /> ASSOCIATES <br /> Creating Space Underground <br />