2010-04-26_PERMIT FILE - C1980007A ‎(3)‎

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 4/26/2010
• Doc Name: Refuse Pile Expansion East
• Section_Exhibit Name: Exhibit 82 Refuse Pile Expansion East
• Media Type: D
• Archive: Yes

c. If design requirements are not met, proceed to Step 3
9 3) Cut slopes not demonstrated to be stable in Step 1 or Step 2 will be stabilized with other
methods such as retaining walls, soil nailing, or other technology.
4.7.2.2 Embankment Slopes
Most of the haul road embankment slopes will be constructed on a side slope that exceeds 20 percent,
so all haul road embankments will be constructed on existing ground that is stepped back, or keyed if
constructed on bedrock, as required by Rule 4.03.1(3)(e)(ii), as shown on the permit drawings.
Embankments will be constructed in uniform lifts of 12 inches or less (loose thickness) and
compacted to a minimum of 90 percent of maximum standard Proctor dry density if the embankment
material contains less than 25 percent rock exceeding 6 inches in its largest dimension. If broken or
crushed rock is used for construction, the approximate average rock size will not exceed 36 inches.
Lifts will be limited to a maximum thickness of 36 inches. Embankment construction will meet the
requirements of Rule 4.03.1(3)(e), Paragraphs (iii ) through (viii).
Due to the steep slopes on which the haul roads will be constructed, embankment slopes have been
designed at a slope of 1.5H: 1V, as shown on the permit drawings, as allowed by Rule
4.03.1(3)(e)(ix). Embankment slopes have been evaluated with the same method as described for cut
slopes to comply with the minimum factor of safety of 1.3 required by the Rules. Figure 4 -2 shows
maximum stable slope heights using this design method. Some slopes shown in the permit drawings
exceed the maximum allowable slope height based on the lowest cohesion value used in the analysis.
Additional geotechnical investigation and design or other slope stabilization methods will be needed
prior to haul road construction in these areas. The approach to establishing a safe slope in such areas
will include the following steps.
1) Sample and test soils intended for use in constructing the embankment slopes:
a. Determine new maximum slope height based on actual test data from soils intended
for construction
b. If design requirements are met, construct slope as designed
c. If design requirements are not met, proceed to Step 2 or Step 3
2) Design embankment with geogrid, crushed rock (1.351-1:1V slope), or other geotechnical
stabilization method to achieve design requirements.
PAMpls \06 CO\26 \06261003 MCC Refuse Pile Site Review & Permit \WorkFiles\Permit Application \Text\2010- 04- 19_RPE East Permit Application.doc18