PERMFILE51446

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: SEDIMENTATION STRUCTURE PON 010
• Section_Exhibit Name: TAB 13 ATTACHMENT 13-3
• Media Type: D
• Archive: No

during passage of the 10, 25, and 1D0-year storm events.
• details Eor the principal and emergency spillway.
TABLE 13-3-5
Emergency Spillway Data Summary
Sediment Pond 010
Principal Spillway:
Type
Inlet Elevation
Lenq[h
Diameter
i
J
Slope
10-Yr, 29-Ht Peak Stage
Emergency Sp111vay:
Type
Channel Protection
Bottom Wld[h
Minimum Oepih (w/freeboard)
Length
Side Slopes
Inlet Elevation
100-year, 24-hour Peak Stage (estimate)
Table 13-3-5 pcesenta the
Riser Inlet (CMPI with
6" orifice
6785.1
140 feet
36" riser with a 24"
barrel (6" orifice)
9
67BB.d5
Trapezoidal Channel
Rock riprap
12 feet
2 feet
60 feet (embankment)
3:1
6788.5
6790.6
Summary
The capacity of Sedimentation Pond 010 is attributed partially to [he embankment and
partially to the pond excavation. During passage of [he 10-year, 24-hour storm the
spillway does no[ discharge sediment downstream nor Ss there any floe through the
emergency spillway. In addition, the splllxay is designed to safely discharge the 25 and
100-year, 24-hour storm event.
The embankment will be constructed to be stable and provide adequate freeboard.
Therefore, based on the design, this structure complies with the appropriate regulations
for a sedimentation structure. Seneca Coal Company will periodically inspect the
structure for sediment storage, structural integrity, and hazardous conditions.
Maintenance and remedial work viii be performed Sn accordance with the approved mine
permit.
13-3-9 Revised 09/08/95