2002-05-13_PERMIT FILE - C1981041 ‎(17)‎

• Permit No: C1981041
• IBM Index Class Name: Permit File
• Doc Date: 5/13/2002
• Doc Name: A-5 Coal Waste Stability Study ‎(Cameo Refuse Piles No. 2 and 3)‎
• Section_Exhibit Name: Tab 13 Appendix 13-5
• Media Type: D
• Archive: No

• 6.0 STABILITY ANALYSIS
6.1 DESIGN PARAMETERS
The design parameters for the slope stability analysis were based
on both previous laboratory testing of the coal refuse material
in Rocky Mountain Geotechnical's report dated October 24, 1980,
and from new laboratory testing on the foundation soils performed
in September and October of 1984. The summary of the shear test
results can be found in Table 1.0 of this report. The properties
of the bedrock assumed in the stability analysis was based on
previous experience with this type of formation in the general
area.
• 6.2 FAILURE MODES
In soil slopes, although planer-type failures are possible in
stratified deposits, the most common mechanism in failure
involves a circular or rotational type of failure. For the
purpose of this analysis, all bench soil slopes were assumed to
have a circular failure mechanism.
6.3 MODEL DEVELOPMENT
In order to properly analyze the stability of the proposed waste
piles, it was first necessary to develop a geometric model of the
slope conditions to be used for purposes of slope stability
analysis. The geometric model for the proposed refuse piles were
• based on the proposed plan and cross-sections for the waste piles
which were provided to Rocky Mountain Geotechnical by Powderhorn
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