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lIII IIIIIIIIIIIIIIII <br />999 <br />~ ~ ROCKY MOUNTAIN GEOTECHNICAL <br />AGh~e ving Harmonp wrth Edr[h <br />May zE, 1982 <br />Mr. William Tate <br />Western P.ssociated Coal <br />410 17th Street <br />Denver, CO 80202 <br />Stability Analysis <br />Blue Ribbon Mine <br />P.ccess Road <br />Dear A:r. Tate; <br />alv .. <br />4S. <br />~-y, ,I !^ t ~2_~ <br />Jl:`: 1 ~~ 1962 <br />MI^'.~=Cl :l~h.'~0 !?LCl_~+it:1A~ i iCtd <br />Cclo. Cap,. a: r!a:ural nasources <br />At tt,e request of F1r. Marv Adam, an analysis was performed b_v <br />Rocky F:,urrtain Geotechnical to evaluate the stabili*_y o: rt,: mine <br />access road at Western Associated Coal's Blue Ribbon !dine, located <br />near Paonia, Colorado. <br />CONDITIONS P'iODELED <br />The analysis gas performed utilizing a typical cross-section of <br />the access road provided by Western Associated Coat. The <br />variable subsurface conditions expected along the access road <br />were moaeled by varying the thickness of the overlyingcolluvial <br />soil and location of the piezometric surface. These conditions <br />are presented graphically on the enclosed figure. <br />The conditions vary from a complete rock excavation to an <br />excavation entirely founded in colluvial soils. <br />Strength properties of the overlying colluvi 1 soils the <br />bearock were obtained from geotechnical investigations pe~~f~rr~~ed <br />by Rocky Mountain Geotechnical in 1981, in the vicinity of the <br />Blue Ribbon Mine access road. The following specific values fcr <br />shear strength, obtained from the previous investicatior, were <br />utilized in the various phases of the analysis. <br />colluvial Soil (measured shear strenoth paramete-s) <br />F.esidua] strength <br />c = 374 psf <br />,0' = 16 ° <br />Peak Strength <br />c. = 446 psf <br />,b' = 1 °' <br />The Railroad Station • 555 E. Pikes Peak Avenue, Suite 107 • Colorado Springs, Colorado 80903 • (3031 634 1999 <br />