1994-01-01_PERMIT FILE - C1981017 ‎(5)‎

• Permit No: C1981017
• IBM Index Class Name: Permit File
• Doc Date: 1/1/1994
• Doc Name: Road Reclamation at Entire Coal Basin Complex
• Media Type: D
• Archive: No

4. Current Road Conditions
In 1983, Geo -Hydro Consultants did an extensive study of the
geotechnical conditions of the existing road cut and fill slopes.
They identified areas of high, medium and low instability based on
weaknesses due to a) high, steep rock cuts with unstable rock, b)
long, steep fill slopes with uncompacted rock, c) areas prone to
water infiltration and d) avalanche paths. Overall, the study
concluded that only a small fraction of the road length on the
property required special treatment for reclamation, however, this
statement was based on the premise that the roads would be
reclaimed according to the approved reclamation plan. This plan
states that very little earthwork will be done for the reclamation
of the roads, but the entire road surface would be seeded and
mulched. Existing drainage patterns, ditches, culverts, etc. would
remain intact. At that time, it was not considered that water would
be allowed to drain over the long, steep fill slopes except at
culvert outlets.
Overall, current road conditions are similar to that described in
the Geo -Hydro report of 1983 and as shown in the cross - section of
Exhibit 2. Although there are some areas of relative instability,
the roads have remained intact.
In the summer of 1989, an incident occurred which should be
carefully considered. A thunderstorm occurred in Coal Basin which
produced a short but intense rainfall. At one location on the road
to Mine #3, runoff breached the ditch at the inside edge of the
road and discharged over the fill slope. The fill slope at this
location was comprised of altered shale that was very coarse,
angular and resistant to chemical weathering. The lack of fine
material on the approximate 45 degree slope resulted in the fact
that no vegetation was present to h e l p h o l d the s o i l . These factors
resulted in the failure shown on the photographs of the following
page. This failure demonstrates that while some of the road fill
slopes may remain intact, they do so only when runoff water is
directed away from the outslope. The combination of an extremely
steep angle with a coarse, cohes i on l ess material results in a f i l l
slope that is simply too unstable to handle any additional problem,
such as unexpected runoff from above. These facts should be
considered in any contemplation of restoring the roads to their
original contour.
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