2015-09-09_PERMIT FILE - C1981019A ‎(2)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 9/9/2015
• Section_Exhibit Name: 4.14 Backfilling and Grading
• Media Type: D
• Archive: Yes

RULE 4 PERFORMANCE STANDARDS
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overburden and spoil on the solid portion of existing benches. The final graded slopes will not exceed the
approximate original premining slope grade as shown on the Postmining Topography Map (Map 19).
Postmining surface drainage channels will be located to minimize erosion and to minimize slippage.
The final pit highwalls will be eliminated in Section 16 by backfilling X seam overburden materials from
the West Pit mining area to achieve the final topography. Rehandle of the X seam overburden will be
occur concurrently with the advance of the multiple -seam advance during the 2003-2010 period. Also, as
mining advances into the final pit, the working area on the pit spoil side will decrease to a point where
insufficient spoil room below the proposed postmining contours is available. When that point is reached,
material will be temporarily placed above the proposed postmining topography. When the final pass of
the West Pit is mined out, this temporarily -placed spoil will be rehandled concurrently with Section 16
virgin and rehandle material to fill and slope the pit to the configuration shown on Map 19 (Postmining
Topography). Because the area will be redisturbed by the rehandle activities, that portion of the north end
of Section 16 that is above final grade will not be topsoiled or otherwise reclaimed until final reclamation.
Final reclamation of the East Pit will take place via the sequence shown on Map 29 (Spoil Grading —
South Area) with the reclamation blocks advancing from east to west or from the topographic bottom to
the topographic top of the mining areas. Just as in the West Pit, all disturbed areas will be returned to
approximate original contour by grading and backfilling with the use of draglines, trucks, dozers, scrapers
and dozers assisiting a dragline. As reclamation of the East Pit progresses, all non -reclaimed areas will be
contained so that any residual runoff from these areas will be isolated within the remainder of the East Pit.
All methods of erosion control and stability such as contour ditches, contour furrows, internal ditches and
internal sumps will be established on an as -needed basis to ensure the integrity of the Prospect Pond and
the surrounding areas include the final East Pit Ditch. Closure of the East Pit is dependent on the final
reclamation and closure of the West Pit as the western most portion of the East Pit will tie-in with the
West Pit in this area.
A haulroad corridor from the Administration/Shop area to the South Taylor Pit will remain in place until
final reclamation is completed in that area. The corridor is sufficient in width to provide a material
balance as the corridor is regraded to the post mine topography. The administration/shop/facilities area
will be the last area to be reclaimed. A light duty road intended for post mining use may be left as a
postmining feature in this corridor with land owner consent.
In addition, Colowyo controls additional coal reserves west and south of Section 9 and 16, outside of
Permit C-81-019, that may be considered for future mine expansion. It is possible that the final plans for
Section 16 and Section 9 could change to provide for such expansion, with any plan changes being
addressed through an appropriate permit revision.
4.14.2 General Grading Requirements
The final graded slopes at the mining operation will not exceed the approximate original premining slope
grade as shown on the Postmining Topography Map (Map 19). Colowyo will retain all overburden and
spoil material on solid portions of existing or new benches. The final highwall at the operation will be
eliminated by backfilling overburden into the final pit area.
Small depressions of a holding capacity slightly greater than one cubic yard of water may be used to
create a moist micro climate to aid in shrub establishment. See Section 2.05.4, Planting and Seedings
Methods for further information regarding these small depressions. Also, several stock watering ponds
will be constructed to compliment the postmining land use. Providing a supply of water is an integral part
of the grazing postmining land use. Colowyo will not be mining on any slopes above 20° as shown on the
Premining Topography Map (Map 18).
Rule 4 Performance Standards 4.14-3 Revision Date: 6/15/15
Revision No.: TR -105