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GEOTECHNICAL STABILITY EXHIBIT <br />The operation proposes a mining slope of 0.5H:1 V for a vertical height of approximately <br />50 feet. Since this slope is steep, the following data is presented by Greg Lewicki, P.E., <br />a registered professional engineer in the State of Colorado with over 24 years of slope <br />stability experience. <br />1) A personal inspection conducted by Greg Lewicki in the summer of 2002 of the <br />existing highwall showed that the material is basically Quaternary age alluvium <br />that is well above the static water level and has had thousands of years of <br />chemical degradation which has caused the fine feldspars and iron minerals to <br />decompose and provide a strong cementing material to hold the slope. Visual <br />inspection of the cementing material showed that the fines had decomposed to <br />produce other minerals which have bonded the larger sized particles together. <br />Significant scraping with a knife is needed to break out sizable amounts of the <br />fines. The material cannot be sampled and sent to a laboratory for triaxial testing <br />since the action of breaking the material out wil{ destroy the chemical and <br />physical bonds that are primarily responsible for the slope stability of the in-place <br />material. <br />2) The strength of the existing material is supported by operation personnel which <br />state that the material is difficult to excavate without appreciable force, including <br />ripping. <br />3) The existing highwall on site is approximately 40 feet high with 0.5H:1 V slope <br />and has been in place for 5 years without the s{ightest sign of instability. There <br />has been no sloughing, no slipping, cracking, bulging, damp areas or any water <br />exiting the slope. <br />4) As mining progresses, existing highwall areas will be backfiAed so that there will <br />