2015-01-22_PERMIT FILE - C1996083A ‎(5)‎

• Permit No: C1996083A
• IBM Index Class Name: Permit File
• Doc Date: 1/22/2015
• Doc Name: CMWB Final Design, WESTEC Report, June 1996
• Section_Exhibit Name: Volume IV Coal Mine Waste Bank Final Design for the mine
• Media Type: D
• Archive: Yes

3.0 DESIGN PARAMETERS
• Parameters for design were determined based on requirements set forth by Bowie Resources, Limited, and
requirements within the Regulations of the Colorado Division of Reclamation Mining & Safety, specifically Rule
4.10 and references therein. The following lists important aspects of the proposed coal mine waste bank design at
the Bowie No. 2 Mine, and the parameters that were used as constraints.
A large portion of the following design pertaining to the Probable Hydrologic Consequences
Sections, Diversion Ditch Design, Sediment pond, etc. located in sections 4.1.4 through 4.3 have
been revised with the design and construction of Gob Pile # 4, and specifics can be found in
Volumes III & IX. With. the approval of TR-44, the Operator began placing waste in Gob Pile #4
which is located to the North of Gob Pile #1. At the time of this writing, Gob Pile #4 has spilled
over into Gob Pile #1 and has `absorbed' a portion of the pile. There is only a small portion of
the original Gob Pile #1 remaining, approximately 1.1 acres, totaling 32,500 CY of waste
material. The diversion ditches associated with Gob Pile #1 have been redesigned and are now
located in Volume III. The `gob pond' sediment pond has been renamed `Pond D' and is also
now located in Volume 111.
Type Coal mine waste bank
Capacity 32,500 CY
As designed, original pile had a capacity of up to 140,000 CY, but was truncated
when it was `absorbed' into Gob Pile #4.
Slopes No steeper than 2 horizontal to 1 vertical (2:1) overall slopes (Rule 4.10.4(4)),
static safety factor of 1.5 (Rule 4.10.4(2))
Compaction 90 percent of the maximum dry density in accordance with American Association
of State Highway and Transportation Officials (AASHTO) T99 -74 (or ASTM D-
698) in 24 -inch maximum thickness lifts (Rule 4.10.4(3))
Haul Road 10 percent maximum overall grade (Rule 4.03.1(3)), 20 -foot wide minimum width,
safety berm, stormwater ditch
Diversion Ditches
Upland runoff areas for "D" ditches shown on Map 20, Vol. II
Flows from a 100 -year, 24 -hour storm event (Rule 4.10.3(2)), or 10 -year, 24 -hour
storm event (Rule 4.05.3(3))
Underdrain System
As required by Rule 4.10.3(1)
Sediment Pond
PHC for Pond "D" shown in Volume III, Appendix 8
Contain the 10 -year, 24 -hour storm and the associated sediment, provide a non -
clogging dewatering device, and an
emergency spillway system (Rule 4.056(3,4))
Overflow Spillway System
Pond "D" Spillway detail shown in Volume III, Appendix 8
A single overflow spillway able to transport flows from a 25- year, 24 -hour storm
event (Rule 4.05.6(5))
Reclamation Salvage and reclamation volumes of topsoil and coverfill material for Gob Pile #1
are located in Appendix A, Volume IX
Stockpiling stripped topsoil, overburden, and haul road cut material in the area of
the proposed coal mine waste bank, covering re- contoured waste with a
• minimum of 4 feet of cover and topsoil, then revegetating (Rule 4.10.4(5))
TR -64 Page 5 09/09
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