2011-06-29_PERMIT FILE - C1981019A ‎(24)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 6/29/2011
• Doc Name: South Taylor Erosion Control And Sedimentation Plan
• Section_Exhibit Name: Exhibit 07 Item 20 -ST
• Media Type: D
• Archive: Yes

•
C7
•
Exhibit 7, Item 20, Table 4
COLOWYO COAL COMPANY
CFniMFNTATIr)N PnNn RtIMMARY PROPOSED PLAN - SOUTH TAYLOR MINE PLAN
Revision Date: 12/31/10
Exh. 7 -20 -2 Revision No.: TR -81
SECTION 28
SECTION 21
WEST TAYLOR
WEST TAYLOR
POND
POND
POND
POND
Active Mining
Post- mining
TR -81
TR -81
TR -88
TR -81
WATERSHED AREA (acres):
Disturbed
0.0
Sec.21 Pond
109.5
0.0
Postmining Topsoiled and Seeded
40.2
no longer
0.0
104.0
Undisturbed
252.7
req'd and
159.4
219.5
1 -2 Year Reclamation
28.1
will not be
0.0
73.2
3+ Year Reclamation
33.8
built
0.0
364.9
354.80
268.9
761.6
Total Area Draining to Pond
Excluded
0.0
478.4
0.0
354.80
747.30
761.60
Total Watershed Area
POND PARAMETERS:
Upstream Toe Elevation Original Ground
7058.0
7456.0
7456.0
Principal Spillway Invert Elevation
7071.0
7471.0
7471.0
Emergency Spillway Invert Elevation
7077.0
7476.0
7476.0
Top of Embankment
7082.0
7481.0
7481.0
Storage Volume Below Emergency Spillway Invert (ac -ft)
8.31
5.64
5.64
Storage Volume Below Principal Spillway Invert (ac -ft)
3.65
2.90
2.90
Storage Volume Below Lowest Spillway Perforation (ac -ft)
1.67
1.77
1.77
Principal Spillway Parameters:
Type
Perforated Riser
Perforated Riser
Perforated Riser
Riser Diameter (in)
18.0
18.0
18.0
Riser Height (ft)
6.6
16.0
16.0
Barrel Diameter (in)
18.0
18.0
18.0
Elevation of Lowest Perforation(s) (ft)
7064.5
7468.0
7468.0
Size of Perforation(s) (in)
3.0
3.0
3.0
Number of Perforations per Elevation
2.0
2.0
2.0
Emergency Spillway Parameters:
Type
Trapezoidal
Trapezoidal
Trapezoidal
Diameter (in)
N/A
N/A
N/A
Bottom Width (ft)
30.0
30.0
30.0
Crest Length (ft)
30.0
30.0
30.0
Side Slopes'z'H:1V (ft)
2.0
2.0
2.0
HYDROLOGIC /HYDRAULIC PARAMETERS:
Base Flow Rates (cfs)
0.00
0.00
0.00
10 -Year, 24 -Hour Storm Event:
Precipitation (in)
1.80
1.80
1.80
Runoff Volume (ac -ft)
3.58
5.81
12.35
Principal Spillway Peak Discharge (cfs)
1.98
12.09
16.80
Emergency Spillway Peak Discharge (cfs)
0.00
0.00
0.00
Peak Surface Water Stage Elevation (ft)
7069.40
7473.02
7474.89
Spillway Design Storm
100 yr /24 hr
25 yr /24 hr
25 yr /24 hr
Precipitation (in)
2.70
2.30
2.30
Runoff Volume (ac -ft)
10.70
9.99
23.05
Principal Spillway Peak Discharge (cfs)
16.32
18.70
22.00
Emergency Spillway Peak Discharge (cfs)
0.00
0.00
56.81
Peak Surface Water Stage Elevation (ft)
7073.28
7475.83
7476.90
Pond Freeboard (ft)
8.72
1
5.17
4.10
SEDIMENT LOADING PARAMETERS (10 -Year, 24 -Hour Event):
Storm Predicted Peak Sediment Concentration (in, mg /1) 163,309
343,608
14,755
Storm Predicted Peak Sett1. Solids, (out, mVl) 0.0
0.0
0.0
Predicted Annual Sediment Loading (ac -ft) 0.21
0.1
0.02
Max. sediment storage elevation (ft) 7060.00
7459.0
7459.0
Available Sediment Storage Volume (ac -ft) 0.49
0.18
0.18
Predicted Number of years to max sed stor. El 2.3
1.8
9.0
Revision Date: 12/31/10
Exh. 7 -20 -2 Revision No.: TR -81