2009-04-29_PERMIT FILE - C1982056 (6)

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The test holes were advanced through the overburden soils and into the underlying bedrock materials with • an all terrain drill rig using 4-inch diameter continuous flight augers. The test holes were logged by an engineer from NWCC, Inc. Samples of the subsurface materials were taken with a 2-inch California Liner sampler. The samplers were driven into the various strata with blows from a 140-pound hammer falling 30 inches. This test is similar to the standard penetration test described by ASTM Method D-1586. Penetration resistance values, when properly evaluated, indicate the relative density or consistency of the soils. It should be noted that practical rig refusal was encountered in the deeper bedrock materials. Depths at which the samples were taken and the penetration resistance values, as well as the depth at which practical rig refusal was encountered are shown on the logs of the exploratory holes in Figure #3. The Legend and Notes associated with the logs are shown in Figure #4. Laboratory Investigation Samples obtained from the exploratory holes were examined and classified in the laboratory by the project engineer. Laboratory testing included standard property tests, such as natural moisture contents, density, grain size analyses and liquid and plastic limits. In addition to the classification tests, swell-consolidation tests, unconfined compressive strength tests, standard Proctor tests and falling head permeability tests were • conducted on samples of the overburden soils and bedrock materials. The swell consolidation test results are shown in Figures #5 through #8. The standard Proctor test results are provided in Figures #9 and #10 and the majority of the laboratory test results are summarized in the attached Table 1. The falling head permeability test results are provided in Appendix A. The laboratory testing was conducted in general accordance with applicable ASTM and/or AASHTO specifications. Subsurface Conditions The subsurface conditions encountered in the test holes were somewhat variable and generally consisted of a very thin layer of natural topsoil and organic materials overlying clays, which in turn were overlying claystone bedrock materials that extended to the maximum depth investigated, 40 feet. A thin layer of natural topsoil and organic materials was encountered at the ground surface in all of the test holes. These materials were generally less than 2 inches in thickness. Natural clays were encountered below the topsoil and organic materials and extended to depths ranging from 4 to 8 feet beneath the existing ground surface. The natural clays were nil to slightly sandy with occasional bedrock fragments, moderately to highly plastic, stiff to hard, slightly moist to moist and brown in color with rust staining. Samples of the natural clays classified as CH-CL, CL, CH, and CL-CH soils in accordance with the Unified . Soil Classification System. Job Number: 08-8241 NWCC, Inc. Page 3