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<br />• R1 Portal. The R1 portal will be located west of the Cow Canyon drainage (Fig. <br />4). Existing slopes in the area range from about 2.3:1 (horizontal:vertical) to about <br />4:1. No signs of existing seeps or large existing unstable areas were observed in the <br />proposed portal area. Subsurface conditions observed in the test trench at the R1 <br />portal location consisted of a thin layer of topsoil underlain by approximately 1(1 feet <br />of overburden soils. The overburden soil appeared to consist of a slope-wash type <br />material consisting primarily of a sandy clay matrix with embedded claystone and <br />sandstone fragments in sizes ranging from gravel to boulder-sized pieces. The <br />slope-wash was underlain by hard sedimentary bedrock consisting of sandstone and <br />shales. Three bulk samples were obtained at the R1 location. One sample consisted <br />of the slope-wash soil, the remaining two samples were representative samples of the <br />excavated soil/backfill material adjacent to the test trench. <br />Laboratory Testin <br />• The results of the laboratory testing are presented in Appendix A with the <br />results summarized on Table A-I. The laboratory testing consisted of Atterberg limits, <br />percent fines, gradation, standard Proctor (ASTM D 698}, and direct shear testing of <br />representative samples of typical spoil. <br />Classification. A sample of intact shale obtained from the test pit at Portal P3 <br />indicated a moderately plastic clay shale with a liquid limit of 38 and plasticity index <br />of 17. A sample of the natural native alluvial soils obtained from a road cut near the <br />toe of the proposed P3 fill consisted of a clayey gravel (GC). A sample of the <br />overburden slope-wash at Portal R1 classifies as a low plasticity clay (CL). <br />Representative samples of the mixture of materials excavated from the test <br />pits are referred to in this report as typical spoil. At Portal P3 the typical spoil <br />consisted of a clayey gravel (GC, Fig. A-1). The typical spoil at Portal R1 classifies <br />as a clay, borderline clayey sand (CUSC, Fig. A-2). The finer nature of the R1 typical <br />• <br />LORENCITO COAL COMPANY, LLC <br />CTL/T 25,663 5 <br />