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c INSPECTIdN REPbRT Site: National King Coal Mine, Hesperus, Colorado 'osp~cted 3y: Dun F.. May, P.E., Project Engineer Ins~-ecticn Gate: C?ua: i3rly Inspection, April 28, 2002 P~n;is: The past and west sedimentation ~ ponds and their embankments appear in good, general condition. Photo 1 shows the avast pond. Both ponds •.vill require the usual annual removal of sediment. (was not able to find the lower end of the low level outlet pipe on the w. est pond. Photo 2 shows the area below the pond where the outlet should be located. Tire outlet pipe shou!d be found and if the opening is blocked it should be cleaned. Periodic mai~~ie:rance of the i~ond outlet works should be carried out to assure that the low flow pipe is clear of debris on both end. The spillway should also be cleared of any debris. The rest of the lower yard are in good condition. Drainage Ditches: The eastside and westside drainage channels appear in good general condition. The armored ditches that run down the sides of the waste pile are performing wall. The ditch on the upper, north side of the waste pile is a "clean water ditch" and should be kept free of coal waste material. Photo 3 shows a section where coal is in this ditch. This ditch should be maintained such that water coming from upstream areas can flow unimpeded along the top of the new access road without being contaminated with coal material. The entrance to a drainage pipe behind the shop is nearly blocked, photo 4. Other ditches, pipes and structures in and around the yard were inspected and appear in good condition. All drainage features have been constructed and are operating as stated in the drainage plan submitted to the Division of Minerals and Geology. Coal Waste Pile: There are no visible signs of structural instability on the waste pile. The problem of oversteepening the toe of the waste pile slope identified in the last inspection report has been corrected as seen in photo 5. It appears that a significant amount of fill has been placed on the top of the pile since the last inspection. This area, partially show in photo 6, has a good, average cross slope but there are low pockets and rough areas. The top surtace should be kept as smooth and uniform as possible so that runoff can flow across the pile to the lower side drainage ditch. Standing water on top of the pile will infiltrate and tend to saturate the pile. This is an undesirable condition and should be avoided. It is important that the waste material be placed in lifts not to exceed 12" to 18" and that compaction results in the density stated in the design report. !t is not possible to determine this by visual inspection and therefore the density should be periodically checked by measurement. In addition, it is recommended that the upstream end of the waste pile underdrain be located and marked. As the pile grow this task will become more difficulty. Except for the items mentioned above the waste pile has been constructed as stated in the reclamation plans submitted to the Division of Minerals and Geology.