_GENERAL DOCUMENTS - C1981017 ‎(142)‎

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Name: Bid Documents ‎(IMP)‎
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

Fred Banta - 2 - September 11 , 1985
According to the results of our work performed within this
study, it is evident and the coal refuse was deposited in
horizontal lifts and compacted according to the original
design. Compactions equal 100 percent of maximum dry
density were found during the investigation. It was
observed that the slo es of the existing facility are
steeper than 2 H V . Such slopes have to be specified
as temporary only. It was also found that recently, coal
refuse was either end-dumped or pushed over the crest of
the existing pile. This resulted in the de ve opment of
sTFallow sloughs, slides and mudflows at the sides ot the
pile-
To achieve long-term stability and to comply with the
specifications and design as included in the permit
application, we recommend to flatten slopes exceeding
2(H) :1 (V) to the original design slope and to eliminate the
end-dumped zones or zones where the refuse was pushed over
the crest."
The mudflows were, in the opinion of the operator' s consultant with which I
concur, the result of the operator' s activities, which did not comply with the
approved permit specifications. The operator failed to comply with the
approved plan. The specifications regarding placement of waste were developed
by the applicant's design consultant, Morrison-Knudsen in 1977. The purpose
of the standard specifications is to provide guidance to the operator to
assure achieving stability. Failure to comply with the specifications
subjects the pile to potential instability, which manifested itself in the
spring of 1984. In failing to follow their own standard specifications for
construction of the approved pile, the applicant demonstrated a lack of
diligence and imprudence.
Further, the operator had experienced an earlier episode of landslide activity
on the coal processing waste pile. On April 8, 1979, the operator experienced
an episode of mudslide activity at the coal processing waste pile. The
operator submitted a narrative concerning this earlier mudflow activity as a
portion of their permanent permit adequacy review response. In that adequacy
response the operator observed;
"The episode of April 8, 1979 was due to the cosmetic
application of some refuse and soil in a reclamation
program that occurred in late (November) 1978. The area in
question was adjacent to the refuse belt conveyor and
facing the office, bathhouse complex. It was the company's
desire to revegetate this area in the fall in order that it
would have an opportunity to utilize the winter moisture
for growth in the spring. The area was quickly done (in
fact, finished in a snowstorm) . The drainage system was
not completed properly which in the spring allowed all of
the drainage to go to this area and collect rather then
into the normal drainage pattern of the pile. The result