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EXECUTIVE SUMMARY <br />Buckhorn Geotech has conducted a preliminary stability evaluation of a proposed new coal <br />waste (gob) stockpile for Bowie Mine No. 2, near Paonia, Colorado. The proposed site is located <br />in the North Fork valley bottom, approximately one -third mile southwest of the existing gob pile. <br />Conventional two- dimensional static limiting equilibrium stability analyses were conducted to <br />evaluate the proposed gob pile. Both drained and undrained analyses were conducted. <br />Three cross - sections through the proposed gob pile were evaluated. Geometry for the gob pile <br />evaluated generally consisted of 3H:1V slopes with maximum overall gob pile heights of 70 and <br />90 feet. Subsurface conditions were assumed based on the mapped geology, our experience in <br />the area, and boreholes drilled by Lambert and Associates (200 1) along the railway south of the <br />proposed site. Foundation strength parameters were estimated based on triaxial testing <br />conducted by Lambert and Associates (2001). Previous triaxial shear testing conducted by <br />Buckhorn Geotech on "un- disturbed" and remolded gob samples was used to characterize the <br />gob strengths. <br />The factor of safety for the analyses conducted ranged from 1.7 to 3.2. A site investigation is <br />recommended to verify foundation conditions and strengths assumed for the analyses. On -going <br />strength testing and in -situ moisture /density testing is also recommended for the coal waste <br />material. <br />Bowie No 2 South Gob Pile preliminary stability evaluation <br />Project #05- 126- GEO -08 <br />Page 3 of 10 <br />