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I <br />' • 1.0 INTRODUCTION <br />1'he purpose of this in-restiga, on is to assess the existing stability and potential <br />hazards along approximately 7,000 fP.et if a sl~dstone cliff at the ~~ wer,~yn,ile Coal <br />Company's Fcidel Creek ?vline operatioi.s, Rcutt County, Colorado (Figure '). Future <br />underground mining is expected to approach the cliff and to undermi,ie it. Surface <br />subsidence of between 3 and 4 feet is expected to result from mining. Our analysis of the <br />data includes the impact of the potential subsidence on the stability of the cliff. Field <br />observations were made during December 17 and 18, 1991 of the stratigraphy, structure and <br />engineering geology along the base of the sandstone cliff north of County Road 27. Our <br />field investigation was hampered by snow that covered the ground and by snow that fell <br />intermittently on the second day. Nevertheless, we were able to collect enough data and <br />make other observations useful for this level of investigative study. We also reviewed <br />available aerial photographs and documents considered appropriate to the study. <br />1 <br />This report includes a general description of the geologic and engineering geologic <br />J • conditions at the site, an assessment of potential engineering geologic hazards, a stability <br />analysis of the existing cliff, potential impact of subsidence on the stability of the cliff, and <br />1 recommendations for mitigating the potential hazards. <br />The tables, figures, and photographs are all located at the end of the report. <br />• 1 <br />