_GENERAL DOCUMENTS - C1981017 ‎(244)‎

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

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Iy� DEPARTMENT OF NATURAL RESOURCES
\* * David H.Getches,Executive Director
*876 MINED LAND RECLAMATION DIVISION
�8 D"ID C.SHELTON, Director
Richard D.Lamm
Governor
DATE: May 15, 1984
TO: Jim Herron _
FROM: Jim Pendleton
RE: Remedial Ana es or Waste Piles at Coal Basin
Pursuant to your request, I have reviewed the submittal made by Mid-Continent
Resources, Inc. in response to a violation issued for failure to properly
place material within their processing waste and rock tunnel development waste
piles at the Coal Basin Mines. This submittal was prepared by Geo-Hydro
Consultants, Inc. , consultant to the operator. The consultant tested
compaction at both structures and performed field examinations to determine
whether the structures were being built in conformance with the approved plans.
Coal Refuse Disposal Structure
Compaction testing was performed by Chen and Associates, under Geo-Hydro' s
supervision. The investigation determined that, while a majority of the pile
had been built properly, . some coal waste material was dumped over the
crest of the existing facilities slopes. " The high moisture content of that
material resulted in mudslide-type slumps occurring. Geo-Hydro states that no
end-dumping or pushing of the refuse material over the crest of the structure
should be allowed. Further, they recommend that the facial problems be
corrected by grading the loose slump material down the pile face and
recompacting it in a facial zone. The foundation should be properly prepared
and material placed and compacted in lifts not exceeding 12" in thickness.
This construction should be supervised by an experienced engineer and
compaction periodically tested utilizing sand-cone methods.
In my opinion this remedial technique will be acceptable, providing that the
structure conforms to the originally approved design footprint. If the
applicant needs to expand the pile in order to accomplish the required
recompaction, an appropriate revision, including stability analysis revisions
would be required. The applicant's strict adherence with the inspection and
reporting requirements of Rule 4.10 will be required.
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. [phone]