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MINED LAND REJ1,A)MATION
723 Centennial Budding, 1313 Sherman Street
Denver. Colorado 80203 TO. (303) 8923567
Hamlet J. Barry, III,
Director
May 22, 1980
TO: Rick Mills
FROM: Jim Pendleton
RE: Yampa Coal's cess Spoil Pile
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As we observed at the site Wednesday, May 14th, the excess.spoil pile
at Yampa Coal's strip pit requires some remedial treatment. The major
problem appears to be oversteepening of the outslopes of the spoil piles.
Small zones of tension cracking, indicative of slope instability, were
evident throughout the outer periphery along the top of the pile. One .
major area of observed cracking and possible slope bulging was observed
on the "reclaimed "face of the pile facing their office area. while
the company's representatives insisted that the angle of slope ranged
from 5:1 to 3 :1 (horizontal to vertical) throughout this area, my
visual perception leads me to believe that actual slope angle was closer
to 2:1 to 4:1.
Unless the company is willing to submit an appropriate stability analysis
to verify the disposal pile's slope stability at steeper angles, I suggest
that you require reduction of the pile's slopes to an angle no greater than
3:1 throughout. Particular and immediate care should be required on that
portion of the northern face of the pile which lies above the undisturbed
mountain valley of the adjoining areas. I suggest that the topsoil
should be removed, the slope regraded to 3 :1, the subsoils properly compacted,
the surface roughened, the topsoil reapplied, and the slope revegetated
as promptly as is practicable. Throughout the remaining areas of the excess
spoil pile's slope, final grading should be capable of achieving a more
stable slope configuration. Until that time, the marginally stable
conditions of the end - dumped spoil pile will probably constitute a major
operational inconvenience for the operator. 'Under the permanent proposed
Yregulations, the end - dumping technique of material placement will be.
disallowed, unless an experimental practice permit is obtained from Yampa
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