2010-05-07_PERMIT FILE - C2009087A ‎(28)‎

• Permit No: C2009087A
• IBM Index Class Name: Permit File
• Doc Date: 5/7/2010
• Doc Name: DRAINAGE AND SEDIMENT CONTROL PLAN
• Section_Exhibit Name: Exhibit 2.05.3-E2 Drainage and Sediment Control Plan
• Media Type: D
• Archive: Yes

Peabody Sage Creek Mine — Drainage and Sediment Control Plan
al (1998). These values are historical values used for the Seneca II Mine and were agreed upon
during discussions between Seneca Coal Company and CDRMS representatives in 1999.
TABLE 2.05.3 -E2 -3
Control Factor Values
Cover
Cover Type
Vegetation
Control Factor
C
Undisturbed
Mixed Brush
25% canopy (2 m tall height), 80%
gr ound cover
0.043
Disturbed
Bare Ground
None
1.0
Reclaimed
Herbaceous
No canopy, 60% ground cover
0.043
2.2.5 Practice Factor
The practice factor (P) is used to account for conservation practices for the watershed. SCCC used a
practice factor value of 1.0 for all conditions. This is a conservative value.
2.2.6 Sediment Particle Distribution
The sediment particle distribution input into the model was obtained from previous analyses
conducted by Seneca Coal Company for the Seneca II Mine.
3.0 POND DESIGNS
This section presents the pond designs and, or as -built plans for Ponds 002, 003, 004, PECOCO and
the pre - treatment sumps located at the portal area and adjacent to the coal stockpile pad. All ponds
and sumps were designed to treat runoff and the associated sediment load from the 10 -year, 24 -hour
storm event in accordance with Rule 4.05.6 of the Regulations of the Colorado Mined Land
Reclamation Board for Coal Mining. Designs prepared for the Peabody Sage Creek Mine utilized
the SEDCAD4 model (Schwab, 1998). Historic designs and, or as -built plans for Ponds 003 and
004 used the SEDIMOT II model (Wilson et al, 1983).
Pond locations and corresponding watersheds are shown on Map 2.05.3 M4. Ponds 002, 003, 004
and PECOCO are existing structures that were designed and constructed as part of mining activities
at the closed and reclaimed Seneca II Mine. There are no changes to the existing land condition
(i.e., extent of disturbance or land use) in the watersheds that drain to Ponds 003 and 004 as a result
of the Peabody Sage Creek Mine surface activities. Consequently, the designs and as -built plans for
these structures presented herewith were adapted from the Seneca II Mine permit — accompanying
text in their respective reports was changed to reflect their inclusion in the Peabody Sage Creek
Mine permit. Ponds 003 and 004 have been approved as permanent, postmine structures by
CDRMS.
The existing configurations for Pond 002 and PECOCO were re- evaluated for the Peabody Sage
. Creek Mine to assure they had sufficient storage capacity to meet the applicable rules and
regulations. Design evaluations for these two ponds are presented in this exhibit. Designs for Pond
002, PECOCO and the coal stockpile pad and portal area sumps are summarized below. Pond
2.05.3 -E2.9