PERMFILE72819

• Permit No: C1992081A
• IBM Index Class Name: Permit File
• Doc Date: 6/19/2006
• Section_Exhibit Name: Tab 12 Facilities
• Media Type: D
• Archive: Yes

previous operator/permittee, H-G Coal Company. The ponds have been referred to as Truck
Loop Pondl (Pond "A", Outfall 006) and Rail Loop Pond2 (Pond "B", Outfall 007). HGTI
identifies the ponds as Truck Loop Pond and Rail Loop Pond - the ponds are permitted by the
Colorado Water 4uality Control Division as industrial wastewater treatment facilities under
Permit No. COG-850006. Exhibit 12-2 shows locations and contributing drainage areas for
both ponds.
The Rail Loop Pond was modified in 1985. A permit revision was submitted (by the previous
operator/permittee) to replace the culvert spillway with a trapezoidal spillway constructed
of fabriform. Certification reports for this pond modification are presented in Appendix
12-1A, Pond Certifications.
The Truck Loop Pond was modified by the previous operator/permittee in June 1992. This
modification was performed to meet CDMG regulations regarding separate pipe spillways. A
12-inch diameter culvert was installed above the existing 24-inch diameter culvert spillway.
Certification reports for this pond modification are presented in Appendix 12-1A, Pond
Certifications.
Capacity tables for the two ponds are shown on Exhibit 12-3 for the Truck Loop Pond and,
Exhibit 12-9 £or the Rail Loop Pond. Per Exhibit 12-3, the Truck Loop Pond has a current •
storage capacity of 0.97 acre-feet at the principal spillway elevation (24-inch drop inlet
pipe), and 1.93 acre-feet at the invert of the emergency spillway (12-inch straight pipe).
As shown on Exhibit 12-4, the Rail Loop Pond has a current storage capacity of 1.89 acre-
£eet at the invert o£ the combination principal and emergency (trapezoidal) spillway.
Area-stage information was compiled from an October 1992 aerial photography survey, a 1991
sediment survey and, for the Rail Loop Pond only, a 1997 as-built survey. Certification of
these as-built drawings is limited to storage capacities only and is not intended to verify
design and/or construction standards. Design and construction certifications were completed
by the previous operator/owner and are referenced above.
Truck Loop Pond
Appendix 12-1, Sediment Control and Pond Design, presents a SEDCAD 9 modeling demonstration
that shows the existing storage capacity (0.97 acre-£eet) is adequate to detain runoff from
the truck dump watershed area generated by the 10-year, 24-hour storm event and, that the
as-built pond configuration meets the requirements of Rules 4.05.6 and 9.05.9.
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As part of the 2,000,000 ton per year unloading system facility modification, to satisfy air
TR-07 2 Revised 06/06