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~~ III IIIIIIIIIIIIIIII REi`E r ~iF-;l INSPECTION REPORT JUL 0 8 1993 Divisor, :r. ,~,:~~~,,.._ , Site: National King Coal Mine, Hesperus, Colorado - /...,.~', Inspected By: Don R. May, P.E., Project Engineer/~/ Inspeotion Date: Quarterly Inspection, June 22, 1993 June 29, 1993 Coal Waste Pile: The coal waste pile and the surrounding area were inspected for compliance with the state approved design and for signs of instability and erosion. The base of the waste pile area has been graded to form nearly level pad. It appears that a fair amount of material has been laid down. This will form a good base for the reshaping of the pile. Since the toe drain must be at the intersection of the waste material and the natural ground, they will have to excavate through this layer of waste to install the drain. Lift heights and compaction appear adequate. See photos. Drainage Ditches/Pines: The Eastside Ditch which diverts upstream flow around the mine is near completion. It has been roughed in for the entire length. The bank slopes, in several places, are steeper than 2:1. This may correct itself with time or they may have to do more backhoe work. The channel has not been ripraped. These conditions can be seen in the accompanying photos. The 36" concrete yard drainage pipe is about 1/2 full of sediment. Even though there is adequate flow capacity, even at 1/2 full, I recommend the construction of small sediment traps at each inlet to this pipe. This will limit the sediment entering the pipes which in turn will allow the clearer water to clean out the existing sediment. Sediment Ponds: The sediment ponds were inspected for excessive sedimentation and erosion with no apparent problems. The pond embankments are also in good condition. The elevation of the low level outlet on the West Pond should be adjusted to comply with the drainage plan. The pipe opening should be 1 ft. above the pond bottom. In addition, the spillway crest on the West Pond should be lowered to an elevation which provides 1 ft. of freeboard, or 1.3 ft. below the crest.