2014-04-03_REVISION - C1982057 ‎(4)‎

• Permit No: C1982057
• IBM Index Class Name: Revision
• Doc Date: 4/3/2014
• Doc Name: Adequacy Response No 1
• From: Seneca Coal Company
• To: DRMS
• Type & Sequence: SL5
• Email Name: JHB
• Email Name: DIH
• Media Type: D
• Archive: No

Now that mining and reclamation activities have been completed, Pond 009 has a total post-
mining watershed area of 438.6 acres. Of these 438.6 acres, approximately 55.0 acres have been
disturbed. The total percent disturbed watershed of Pond 009 is 12.5 percent. Pond 016 has a
total post - mining watershed area of 384.8 acres. Of these 384.8 acres, approximately 25 1.0 acres
have been disturbed. The total percent disturbed watershed of Pond 016 is 65.2 percent. Both of
these watersheds have percent disturbance less than 80 percent. Therefore, Pond 006, with
greatest disturbance area, was selected for performing pre - mining and post - mining model runs
using SEDCAD; the model results are considered representative of the SL -5 bond release
application area. Current cover data from the vegetation sampling efforts at Seneca II -W was
considered in determining post - mining `C Factor' values. Other relevant model input values used
in the PHC demonstration were also used in the attached SEDCAD modeling. The pre - mining
and post - mining results determined from the SEDCAD modeling are provided in the table below.
The pre - mining and post - mining SEDCAD runs for Pond 006 are attached.
While both initial SEDIMOT II modeling and SEDCAD modeling show an increase in sediment
yield in the post - mining scenario, the total sediment yield is still relatively low. Sediment yields
of this amount are not representative of unstable topographies with respect to erosion. Because
reclamation efforts in all areas of the SL -5 bond release application area were uniform, the
results from the Pond 006 watershed are representative of the rest of the SL -5 bond release
application area, and indicate all parcels associated with the application are adequately stable
with respect to erosion.
Attached is one (1) bound copy of the Peabody Sage Creek Mine 2013 Annual Reclamation
Report (ARR). If you or the Division staff has any questions or comments, please contact me at
(970) 276 -7003.
Peak
Runoff
Sediment Yield
Watershed
Condition
Discharge (cfs)
Volume (ac -ft)
(tons /acre)
0063
Pre - mining
0.08
0.04
0.0
Post -
0064
1.14
0.92
0.0101
mining
While both initial SEDIMOT II modeling and SEDCAD modeling show an increase in sediment
yield in the post - mining scenario, the total sediment yield is still relatively low. Sediment yields
of this amount are not representative of unstable topographies with respect to erosion. Because
reclamation efforts in all areas of the SL -5 bond release application area were uniform, the
results from the Pond 006 watershed are representative of the rest of the SL -5 bond release
application area, and indicate all parcels associated with the application are adequately stable
with respect to erosion.
Attached is one (1) bound copy of the Peabody Sage Creek Mine 2013 Annual Reclamation
Report (ARR). If you or the Division staff has any questions or comments, please contact me at
(970) 276 -7003.