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,. _ ,~ ~.~ III IIIIIIIIIIIII III • o`'~J~ ~ .~-sTF "~ INSPECTION9Rtrun f - ~ ~~~ • • i~f:V LJf»J ~`~u r; Site: National King Coal Mine, Hesperus, Colorado ~ ~~^f.,~5~~£~ ;";;r Inspected By: Don R. May, P.E., Project Engineer ~`~°~;;j'~,~~~Lh" Inspection Date: Quarterly Inspection, January 2, 1999 ~`~~~+!--~ ~•"' Ponds: The east and west sedimentation ponds and their embankments appear in good condition. The west pond is shown in photograph 1. The overflow pipe connecting the west pond to the east pond can be seen on the left side. As mentioned last quarter, the elevation of the inlet of this pipe relative to the high water level in the west pond should be confirmed. In addition, the entrance to this pipe should be covered by a screen to prevent blockage by debris. All pipe inlets, outlets and spillways should be periodically cleaned. The west pond staff gage read less than 2 feet. Drainaoe Ditches: The east side (below waste pile) and west side drainage channels appear in good general condition. The ditch draining the hillside behind the shop has been blocked by a loader bucket of dirt as seen in photograph 2. This blockage should be removed. The black corrugated plastic pipe which begins behind the shop and exits into the main channel which empties into the west pond should be cut off at the point at which it penetrates the ditch bank. Rip-rap should be placed below this pipe to prevent scouring. Photograph 3 shows the clear water intercept ditch on the east side of the yard above the office. As seen this ditch is partially blocked and should be cleaned. The remainder of the yard drainage features appear in good shape. Ditches have been cut down the face of the water rock pile on both sides as required by the reclamation plan. In both cases the ditches have not been armored and some erosion is occurring (photographs 4 and 5). Due to the rocky nature of the material, erosion has been restricted and does not pose any immediate threat. However, in the long run, these ditches need to be armored with rip rap (or alternative treatment) as stated in the plans. The inlet to the pile on the north side should have a trashrack (photograph 4). All drainage features, with the exceptions stated above, have been constructed and are operating as stated in the drainage plan submitted to the Division of Minerals and Geology. Coal Waste Pile: Based on a June 30, 1998 survey the upper'/< of the face of the waste pile along the entire length is slightly steeper than the design value of 2.5:1. This area should tie regraded and surveyed to confirm the design slope. In addition the design calls fora 2% cross slope and a 1% longitudinal slope on the top of the pile. Recently placed fill should be graded and compacted to conform to the reclamation plan requirements. The end of the existing underdrain should be located and plans for the construction of the structure to connect it with the extension should be made as per the reclamation plan. Except for the items mentioned above the fill on the waste pile has been constructed as specified in the design approved by the Division of Minerals and Geology.