2008-10-07_PERMIT FILE - C1981047 (4)

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s to 6,340' at the south end and new dewatering devices were installed. Pond No. 1 discharges into Hubbard Creek through discharge point 001 of NPDES Permit CO-0033553. The embankment of this pond has had a history of overtopping during high runoff in Hubbard Creek. Due to our commitment November 26, 1985 to reclaim this pond, the decision has been made to replace its sediment control function by a proposed Pond q5 and to allow Pond #1 to overtop again during high flows in 1986. The No. 2 Pond discussed in Appendix C was eliminated with the bench stabilization project. The No. 1 Pond impounds the water that would have been collected by No. 2 Pond. The No. 3 Pond was installed in 1980 as a settling pond for runoff south of the mine bench. This runoff area was reduced to sub area 4A, Exhibit H, when ditch 1 was converted to a diversion ditch. This pond has a capacity of 0.13 a.f. of sediment and 0.10 a.f. of water storage. The required capacity according to page 1 of 10, Appendix C is 0.13 a.f. of sediment and 0.03 a.f., of water storage. Discharge from this pond is through discharge point 002 of NPDES Permit No. CO-0033553. The No. 4 Pond was installed in 1980 as a settling pond for runoff from the lower stockpile area, sub area 8, Exhibit ~. This pond has a sediment capacity of 0.08 a.f. of sediment and 0.06 a.f, of water capacity. Design capacities are 0.13 a.f. and 0.06 a.f. respectively. Discharge from this pond is through discharge point 003 of NPDES Permit No. CO-0033553. For the initial reclamation phase drainage system will be changed on the east be no change on the west side of the creek. to represent the drainage areas and pattern The C-# pages have been added to Appendix C for these changes. at Blue Ribbon nearly all of the side of the creek. There will Exhibit H-1 has been prepared s during this reclamation phase. to show the design calculations The No. 5 Pond will be installed to replace the No. 1 Pond. The • design size was calculated in Appendix C pages C-1 through C-3 using drainage lO6i (Rev. 6-11-86)