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• Mr. Jeffrey Dubbert, Blue Mountain Energy Inc., Deserado Mine Slope Stability Calculations Coal Refuse Area # 2, #3 & #4, Deserado Mine, Colorado lone 23, 2004 Page 2 Following is a summary of the results of these sheaz strength analysis. Coal Refuse Testing -Lincoln DeVore and Grand Junction Lincoln DeVore • Job # Date of Phi Tag Cohesion Sample Moisture Type report Angle Phi psf Density P~ 56722 8-I-85 29.0 0.554 576 85.2 18.9% Remolded - uiaxial, multistage 5ne grained 65301 4-30-87 36.5 0.739 58 80.7 26.4% Remolded -direct sheaz 65328 6-8-87 37.0 0.755 94 80.0 Remolded -direct shear 65328 6-8-87 37.5 0.767 263 80.0 Remolded - direct sheaz 86432 1-5-98 31.5 0.614 139 79.6 Remolded -multistage, direct sheaz 86439 1-5-98 29.1 .556 457 78.2 Remolded - w/filter cake, direct shear, multistage 90875 5-8-04 3939 0.835 469 71.9 33.2% Remolded -multistage, peak wmposite direct sheaz, cycled composite Native Cla Formation from Chen & Assoc., ort # 21,358, 12-80 #21,358 1980 26.0 0.404 0 110.0/115 Triaxial sheaz - 1.9." dia. moist Cal. Liner Grand Junction Lincoln DeVore placed two auger borings on the Coal Refuse Area #2, #3 and #4"on 4-7- 04 and 4-9-04. The borings were drilled using a C.M.E. model drill, with 3.75" id Hollow Stem Auger. The holes were drilled to depths of 40 to 49 feet deep. The drill encountered effective auger refusal in both borings, due to the tight, well compacted coal refuse. The coal refuse was sampled using a 2 %z " id/1.875" id California Split Spoon Sampler, with liners. The sampler was driven with a C.M.E. Automatic Hammer. The samples are probably compacted to.a small degree, due to the `Blum' Drive Shce. The coal refuse was found to be fairly consistem, of medium high density and dry to slightly damp. No free water or wet zones were observed. Water wnditions within the coal refuse pile were assumed to be just below saturation but, a free water surface which would affect the entire coal pile was not allowed. The assumptions for this currentslope stability study aze essemially those utilized for previously calculations performed by Lincoln DeVore and Grand Junction Lincoln DeVore. Following are the minimum Factors of Safety for the refuse coal for the modified pile, to include, the factors of safety utilizing a horizontal earth quake loading ccefficiem of 0.050 • and a vertical earth quake loading coefficiem of 0.0.