2016-07-01_REVISION - M1977141 (2)

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• Fountain Formation laid back to a single overall slope angle of 1.5H:1V (33 degrees). • Rockfall catchment berm on minimum 20-foot-wide bench, constructed at the toe of the Fountain Formation and on top of the dacite sill at the contact of the two units. • Rockfall catchment berm on minimum 20-foot-wide bench, reclaimed or constructed at existing benches and at the toe of the dacite unit. Where esthetics are important, where space limitations prevent a single overall slope, or where reduced excavation volumes are desired, the final reclamation slopes can have the following configuration (See Figures 7.6 through 7.10 of Attachment A): • Dacite left at existing slope angle with loose rock scaled from the face of the dacite. • Fountain Formation white sandstone units excavated to a slope angle of 0.5H:1V (63 degrees). • Fountain Formation interbedded red sandstone and siltstone units excavated to a slope angle of 2H:1V (26 degrees). • Minimum 15 foot benches at the top of the red sandstone and siltstone units. • Rockfall catchment berm on minimum 20-foot-wide bench, reclaimed or constructed at existing benches and at the toe of the dacite unit. These slope angles and configurations are subject to the conclusions, recommendations, and limitations of the detailed engineering stability analysis performed for the highwall and rock slopes and presented in Attachment A. 7.0 FILL SLOPE ANGLES AND CONFIGURATIONS The existing fill slopes and future constructed fill slopes can be graded to a final configuration as follows (See Figures 4.2 and 4.3 of Attachment B): • Bench Slope Angle 26.6 degrees or 2H:1V • Maximum Bench Height 50 feet • Minimum Bench Width 15 feet • Maximum Overall Slope Height 150 feet Fill slopes should be constructed using overburden materials with the following characteristics: 86995/DEN8R017 Page 4 of 5 February 2008 Copyright 2008 Kleinfelder West, Inc.