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1. Scope and Purpose <br />In compliance with Colorado State reclamation regulations pertaining to hydrology of mine <br />sites, a design for the drainage system at National King Coal Mine in presented in this <br />document. Detailed hydrologic and hydraulic analysis of sedimentation ponds, channels and pipes <br />were performed as part of this study. <br />2. Mine Drainage Plan <br />The drainage plan for the National King Coal Mine has two components: 1) diversion of <br />uncontaminated water, originating upstream of the mine yard, around the yard to the discharge <br />point at the north end of the site and 2) routing of water from the mine yard and some adjacent <br />areas through sedimentation ponds. This is achieved through a series of open channels and pipes. <br />Figure 1 is a schematic diagram of the drainage basin which shows the different subbasins. The <br />large azeas labeled East and West Basins aze diverted around the mine. The area labeled mine <br />yard is the only area which generates contaminated water. The two small natural areas adjacent <br />to the mine yard do not generate contaminated water but are routed to the sedimentation ponds <br />in order to simplify the drainage system. <br />2.1 Diversion of 1Jncontaminated Runoff <br />~ Runoff from the East Basin is intercepted above the coal waste pile in an open channel and <br />routed through reach 1 as shown in Figure 2. Reach 1 terminates at a junction with a buried pipe <br />designated reach 2. Runoff from the hillslope on the north side of reach 1 will be intercepted <br />by this channel. The flow will then travel through reach 2 to a point just behind the end of the <br />main office building where it enters an open channel labeled reach 5. Reach 3, as shown in <br />Figure 2, is an existing buried pipe which intercepts runoff from the West Basin upstream of the <br />mine yard. The end of reach 3 is below the elevated conveyor belt. At this location a new pipe, <br />reach 4, has been constructed which connects to the reach 3 pipe and transports flow to the reach <br />5 open channel which is also used by reach 2. Reach 13 is a an open channel which intercepts <br />the flow from the small natural area above it and discharges it into reach 5. The reach 5 open <br />channel conveys all of the clear water diversion runoff the remaining distance to the discharge <br />point in the field at the northeast corner of the mine site. <br />The remaining components of the drainage system, labeled reaches 6-12 on Figure 2, are <br />used in conveying on site yard runoff to the sedimentation ponds. <br />2.2 Treatment of Yard Runoff <br />All runoff generated from the yard area will be routed to the sedimentation ponds. Two <br />small, natural areas, one located on the hillside west of the mine entrance and the other on the <br />,7une 1995 <br />