PERMFILE112949

• Permit No: C1981033
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: EXHIBIT 20 HIGHWAY ROAD, BEAR 3 MINE
• Media Type: D
• Archive: No

• SLOPE STABILITY ANALYSIS
ACCESS ROAD FILL
MINE N0. 3
BEAR COAL COMPANY
An estimated factor of safety for the fill slope of the access road at
the Bear Coal Company Mine No. 3 near Somerset, Colorado was made to
confirm the stability of the road and to satisfy sections of the
Regulations for Coal Mining of the Colorado Mined Land Reclamation
Board. For calculation purposes, the following assumptions were made:
• The material forming the fill consists of minus six (6) inch
material compacted in continuous thin uniform horizontal lifts
• The shear strength of the material is estimated ~to have a
cohesion (c) of 210 to 360 lb/f t2 and a friction angle (0) of
16 to 23 degrees
•
• Failure is assumed to occur on a circular failure surface
which passes through the toe of the fill
• Field observations verify that no groundwater is present in
the area of the fill and that a "fully drained slope"
condition exists
• foundation conditions consisted
competent sandstone material.
utilized by heavy equipment and
equipment haulage. No evident
weakness or groundwater were
material
of a roadbed excavated in
The roadbed was previously
highway trucks for coal and
of fracturing, planes of
evident in the foundation
The factor of safety of the slope is defined as:

F = Shear strength available to resist sliding
Shear stress mobilized along failure surface