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a <br /> <br />INVESTIGATION <br />Field Investigation <br />We visited the site on September 5, 1997 to observe conditions and <br />excavation of test pits at the proposed embankment locations. One or two test pits <br />were excavated at each location depending on the conditions anticipated. The test <br />pits were excavated with grubber-tired backhoe to depths of 4 to 10 feet. Bulk <br />samples of the various soil types encountered were obtained from the test pits. <br />Occasional samples were obtained by driving athin-walled brass tube into the soils <br />(1.935-inch diameter). Conditions at the proposed embankment sites were visually <br />observed, the test pits logged, and samples returned to our laboratory for testing. <br />Subsurface Conditions <br />• Logs of the test pits at each pond location are presented on Figs. 8 through <br />10. Following is a discussion of the soil conditions found at each pond location. <br />Pond 004. Soil conditions found in TP-1 consisted of approximately 4 feet of <br />very clayey sand soils underlain by clay soils with gravel. This test pit was <br />located just above and to the side of the drainageway. The soils were very <br />stiff to hard and practical refusal with the backhoe was encountered at a <br />depth of 6 feet. The soils became increasingly gravelly with depth and we <br />believe bedrock may be found at a short distance below the bottom of the test <br />pit. Laboratory testing of the soils indicated the material was a clayey sand <br />with 41 percent passing the No. 200 sieve. A liquid limit of 28 percent and <br />plasticity index of 14 percent was measured. <br />Test Pit 6-A was not excavated with a backhoe, but consisted of a bulk sample <br />of the soil from a columnar structure located within the drainageway. Testing <br />indicated the soil had a moisture content of 2.4 percent with dry densities of <br />99, 101, and 103 pcf measured on 3 samples. <br />Pond 006. Soils conditions found in TP-2 and TP-3 consisted of a thin layer <br />of dark brown to black topsoil underlain by stiff to very stiff clay soils. <br />• Laboratory testing indicated 52 to 55 percent passing the No. 200 sieve, with <br />a liquid limit of 33 percent and a plasticity index of 15 percent. <br />LORENCITO COAL COMPANY, LLC <br />SMALL SEDIMENTATION EMBANKMENTS <br />CTLlT 26,559 5 <br />