Laserfiche WebLink
- _, <br />~: ; <br />INSPECTION REPORT _ ~~ <br />Site: National King Coal Mine, Hesperus, Colorado ~ ~! 1 arc {'~ <br />Inspected By: Don R. May, P.E., Project Engineer <br />Inspection Date: Quarterly Inspection, April 18, 1999 <br />Ponds: The east and west sedimentation ponds and their embankments appear in good ' <br />condition. The west pond is shown in photograph 1. The overflow pipe connecting the '_ <br />west pond to the east pond can barely be seen on the right side. As mentioned last <br />quarter, the elevation of the inlet of this pipe should be checked to assure it is below the <br />low level outlet and spillway elevations. This pile needs screen to prevent blockage. <br />The west pond staff gage reads about 2 feet. ~i <br />Drainage Ditches: The east side (below waste pile) and west side drainage channels <br />appear in good general condition as does the drainage system in the mine yard. <br />Photograph 2 shows the lower yard area looking from the ponds up toward the coal <br />stock pile. Ditches draining the hillside behind the shop have been cleaned since the last <br />inspection, photograph 3. They are in good shape. <br />Photograph 4 shows the ditch on the north side of the waste pile face looking down the <br />slope. Due to the rocky nature of the material the channel has partially armored itself. <br />Erosion has been minimal and does not pose any immediate threat. However, in the <br />tong run, the ditches (both sides of the pile) need to be armored as stated in the plans. <br />The inlet to the pile on the north side should have a trashrack. Photograph 5 shows the <br />same ditch as photo 4 but looking upstream across the top of the waste pile. As seen <br />this ditch is clean and uniform. Photograph 6 shows the similar ditch on the south side of <br />the waste pile. In this case the intersection of the graded slope and the piles of dumped <br />waste rock form the ditch. With the rough edges and partial blockage it is not apparent <br />that runoff will flow toward the front of the pile as designed. Care should be take to form <br />a uniform flow section with a positive slope toward the face of the pile (similar to the <br />north side). <br />All drainage features, with the exceptions stated above, have been constructed and are <br />operating as stated in the drainage plan submitted to the Division of Minerals and <br />Geology. <br />Coal Waste Pile: Rather extensive rill formation has occurred on the face of the waste i~ <br />rock pile. An erosion inhibiting, fiber mat is currently being placed on the face to aid in p <br />revegetation. The mat and vegetation should stabilize the surface of the slope. However <br />if it doesn't the slope should be regraded to remove the rills and a different slope ' <br />treatment should be applied. Recently placed fill on top of the pile should be graded and , <br />compacted to conform to the reclamation plan requirements. Density tests on the fill ~j~ <br />should be performed to assure compliance with the plan specifications. The end of the '~i <br />existing underdrain should be located and plans for the construction of the structure to i~I <br />connect it with the extension should be made as per the reclamation plan. ~',~, <br />Except for the items mentioned above the fill on the waste pile has been constructed as j, <br />specified in the design approved by the Division of Minerals and Geology <br />