2011-01-13_PERMIT FILE - C1981038A (6)

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2.05 APPLICATION FOR PERMIT FOR SURFACE OR UNDERGROUND MINING ACTIVITIES - MINIMUM REQUIREMENTS FOR OPERATION AND RECLAMATION PLANS. • The spillway will 'safely discharge runoff from a 25-year, 29- hour precipitation event. This is discharged with the spillway flowing at a two-foot depth, leaving one foot of freeboard to the top of the dam. (See calculations in Ponds, Impoundments and Dams Appendix.) The dam was constructed eight inches over design height for possible settlement of the dam. The top of the embankment averages ten feet wide and the side slopes on both upstream and downstream sides are approximately 2(h):1(v). vegetative matter was removed before construction of the dam. All backfill material used within the dam is free of sod, roots, frozen soil, or coal development waste. Backfill was compacted with conventional earthmoving machinery and methods. The dam was inspected by a Professional Civil Engineer. All disturbed areas have been re-vegetated, following the Revegetation Plan. (See Section 2.05.9). The pond is currently being inspected following the Sedi- mentation Pond Structural Inspection Program. See Ponds, Impoundments and Dams Appendix. The pond will be removed following usage. It will be adequately backfilled and rip-rapped. It is contemplated that additional hydrological data will have been gathered by final abandonment, when a judgment can be made on the best alternatives for • backfilling, etc. Current plans are to remove the dam, backfill the pond, and restore natural drainage. Sedimentation Ponds - Reclaimed West Mine Two sediment ponds will be utilized to control run-off from the reclaimed West Mine. They are constructed on top of the East Roatcap Creek culvert. The design of the ponds are presented in Volume BA - Surface Drainage/Mine Facilities and consist of the two ponds in a `series' configuration. Pond W-2 does not adequately contain the 10-year event, but any overflow will be contained in Pond W-1 which has excess capacity available to contain overflow from Pond W-2. The ponds and culvert will be reclaimed. Sedimentation Pond - Coal Stock ile Area One sedimentation pond is located immediately West of County Road over the railroad and South of State Highway 133. It is located in the NW aNW ,, Section 32, T.13.S., R. 91.W., 6th P.M. This Dam was approved by the Office of Surface Mining and the Colorado Mined Land Reclamation Board in the existing Mine Plan. Drainage ditches have been installed to intercept surface runoff and direct it to the sedimentation pond. The dam is constructed using compacted earth fill. Plans and specifications are as shown in Ponds, Impoundments and Dams Appendix. The pond was constructed in 1979. The coal stockpile dam is an existing structure and is located • slightly West of the Truck Dump Station. It is not located within any stream channel, and discharge, i£ any, drains into Stevens Gulch. Permit Renewal - 22 - 01/03 /h2-)oti