2017-03-23_PERMIT FILE - C1981019A

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 3/23/2017
• Doc Name: Permits
• Section_Exhibit Name: Volume 15 Rule 2
• Media Type: D
• Archive: Yes

RULE 2 PERMITS
The temporary spoil pile will be used to fill and recontour the final pit sequence in the final three years of
mining activities (See Map 29C — Temporary Spoil Pile Design). Out of pit stored spoils will be used in
the construction of the post mine topography. Approximately 168 million cubic yards of storage capacity
for the temporary spoil stockpile will be needed.
The toe of the fill will be placed at the bottom of the Little Collom Gulch Drainage and the stockpile will
eventually extend upward about 600 feet in thickness to an elevation of 7000. The stockpile will remain
in place until the last few years of mining and will have a life of about 17-22 years depending on
production rates. As such, the lower portions of the stockpile will be completed and stabilized before the
top is completed. To ensure that a phreatic water surface does not develop during the life of the stockpile,
a rock drain will be installed at the base of the fill along its entire length. The spoilpile will be confined
by the valley slopes on both sides. Volume 20, Exhibit 23, Item 1 and Item 2 provide the geotechnical
report for the temporary spoil pile.
The temporary overburden stockpile will be constructed in 50 to 100 foot lifts by use of trucks, dozers
and loaders. Each lift will be dumped at angle of repose. Maintenance techniques will consist of blading
of roads and ramps, along with the use of dust control during active times of operation. During
construction a dozer will be used develop and spread the end -dumps created by the trucks, this will be the
primary method used to build the temporary overburden stockpile. Sediment control will be implemented
to ensure adequate containment of potential runoff throughout the life of the operation. Chemical
stabilization and/or temporary seeding via the broadcast method may be employed during inactive times
of operations on the temporary stockpile to reduce the erosion potential utilizing the following seed mix:
Western wheatgrass @
4 lbs PLS/Acre
Mountain Brome @
41bs PLS/Acre
Kentucky Bluegrass @
2 lbs PLS/Acre
Sanfoin @
21bs PLS/Acre
Total
12 lbs PLS/Acre
The area that was disturbed in conjunction with this stockpile will be reclaimed in accordance the
procedures outlined in the reclamation plan.
2.05.3 (7) Coal Handling Structures
Please Refer to Volume 1, Section 2.05, Coal Handling Structures and Map 22B.
2.05.3 (8) Coal Mine Waste and Non -Coal Processing Waste
Not applicable. Colowyo uses dry crushing facility for coal preparation; no coal processing waste, as
defined in Rule 1.04 "Definitions", is produced from any part of the mining operations.
2.05.3 (9) Return of Coal Mine Waste to Abandoned Workings
No coal processing waste or coal mine waste as defined in Rule 1.04 "Definitions" is produced from any
part of the Colowyo mining operations. Therefore this section is not applicable.2.05.4 (1)Reclamation
Plan
The reclamation objective for the Collom permit expansion area is to restore the mined area to a land use
capability which will be equal to or better than that which currently exists. Reclamation activities must
return the mine area to previously determined pre -mine land uses. Reclamation practices aim to stabilize
Collom — Rule 2, Page 82 Revision Date: 12/30/16
Revision No.: TR -108