_GENERAL DOCUMENTS - C1981017 ‎(219)‎

• 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

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XVI. Backfilling and Grading - Rules 2 .05.3 (9 ), 2.05.4 (2 ) (c) , 4.09 and
774
The findings document of August, 1984 imposed Stipulation r6 upon the permit.
This stipulation required Mid-Continent to complete a geotechnical
investigation and stability analysis of the proposed backfill configurations
for the five portal benches at Coal Basin Mines. All requirements of this
stipulation have now been fulfilled by the operator. Appendix V-E-2 of the
permit application contains the geotechnical investigations for the mine
portal benches and the haul roads.
The 1984 findings document also imposed Stipulation #7 upon the permit. This
stipulation dealt with submittal of a detailed backfilling and grading plan
for the preparation plant area. All requirements of this stipulation have
been fulfilled by the operator and the stipulation is no longer in effect.
The preparation plant backfilling and grading plan is contained within
Appendix V-E-3 of the permit application.
XVII. Mine Facilities , Coal Handling Structures , Support Facilities -
Rules , _ an
The description in the Findings Document remains valid for the existing
operation.
XIVIII. Underground Development Waste, Coal Processing Waste and Non-Coal
Processing Waste - Rules an
T77—
The description of the old refuse pile (active until July 1984) and the newer
Sutey Refuse Area remain valid for the existing operation. A description of
the disposal area for underground development waste from the rock tunnel was
not included in the original Findings. The description is contained herein.
Material excavated from the construction of the rock tunnel has been placed in
the designated Pock Tunnel disposal area. To date Mid-Continent estimates
that approximately 364,000 cubic yards of material from tunnel excavation have
been placed in the Rock Tunnel disposal site. The approved waste disposal
facility design has a capacity of 1 .08 million cubic yards. In construction
of the current pile, the tunnel spoil material was spread on the waste pile so
as to maintain a perimeter slope at the ratio of 2h:ly or less. The stability
analysis of the waste pile was developed by Lincoln DeV ore in 1979. Stability
analysis were performed on slopes not exceeding 60 feet in height. The
analyzed slope had two 10 foot wide benches included. Slope between the
benches was 2h:ly. A minimum factor of safety was found to be equal to 3.5.
The waste rock disposal area was designed as a zoned embankment. The design
called for compaction of the outer shell of the waste pile to 90% of Maximum
Proctor Density. The outer parameter is to be built in lifts not to exceed 12
inches loose thickness. The material located inside the outer shell can be
spread in lifts not exceeding 2 feet in thickness. No compaction is required
for the interior zone of the facility.
The proposed operation is in compliance with the requirements of this section.