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0 <br />. SCOPE <br />This report presents the results of our Stability Analysis and Geotechnical <br />Recommendations regarding the Lorencito Surface Mine Phase I in Las Animas County, <br />Colorado. Our investigation, analysis and report addresses: <br />1. Excess Spoil Fills 4 through 9, <br />2. The first phase of surtace area mining, and <br />3. Contour mining in Lorencito and Little Jeff Canyons, <br />4. Sedimentation pond embankments associated with the above fills. <br />The purpose of our evaluation was to assess geotechnical conditions, stability <br />conditions and construction procedures to assist in mine planning and permitting. The <br />scope was described in our Proposal No. 01-0012 dated January 5, 2001. Our <br />evaluation included: <br />1. Characterizing soils, bedrock and geologic conditions based upon a <br />•'~ review of information provided by Greystone and our experience at the <br />nearby New EIk/Golden Eagle Mines. Technical publications, previous <br />investigations by CTUThompson, Inc. and available geologic/soil <br />information were reviewed. Afield investigation consisting of observation <br />of each fill area, test pits in selected areas and laboratory testing of <br />representative samples was performed. <br />2. Evaluation of the proposed fills to characterize and group the types of fills <br />according to relevant engineering and regulatory criteria. <br />3. Performing stability analysis for typical fill sections. Engineering <br />properties (density and strength), water, earthquake and foundation <br />conditions were varied to develop an understanding of minimum <br />requirements for stability and the sensitivity to the various factors. <br />4. Developing recommendations regarding proposed configurations, slope <br />angle, and proposed drain systems. Proposed construction procedures <br />(site preparation, placement and compaction procedures, drain <br />requirements) along with inspection procedures are also discussed. <br />• LORENCITO COAL COMPANY, LLC <br />LORENCITO SURFACE MINE -PHASE I <br />CTLR 3Z, 611 <br />1 <br />