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1.0 Scope and Purpose <br />• The drainage system for the proposed King II Mine is presented in this document in <br />compliance with Colorado Mined Land Reclamation Board for Coal Mining Regulations, <br />pertaining to hydrology of mine sites effective August 30, 1980. <br />2.0 Mine Drainage Plan <br />The drainage plan for the King II Mine has two components: 1) diversion of <br />uncontaminated water, originating upstream from the mine facilities in undisturbed areas, <br />around the mine facilities to a discharge point located south of the surface facilities and <br />2) routing of water from the surface facilities to and through the sediment pond. This is <br />accomplished with a series of open channel ditches and culverts. Figure 1 is a schematic <br />diagram of the drainage basin with their relative sizes. <br />SEDCAD 4 from Civil Software Design was used to calculate the sizes of the various <br />diversion structures. <br />2.1 Diversion of Undisturbed Runoff <br />Drainages from undisturbed azeas are routed around the surface facilities by four <br />undisturbed drainage ditches UDD-1 through UDD-4. The locations of the four <br />undisturbed drainage ditches and two culvcrts are shown in Figure 2. Information on the <br />• diversion facilities is shown in Table 1-Undisturbed Drainage Structures. Undisturbed <br />drainage ditches were designed to handle a 25yr-24hr event <br />2.2 Treatment of Disturbed Runoff <br />Runoff from the disturbed area (22.36 acres) will be directed to the sediment pond, which <br />will be located south of the t~s~"aee-facilities. It is esf t approx a <br />the proposed disturbed area (15.72 acres) will actually be disturbed. The remainder of <br />the property (6.74 acres) will be located in steeper azeas that will not be disturbed from <br />mining activities. The sediment pond has been sized to handle the runoff from the total <br />22.46 acres. <br />3.0 Drainage Basin Characteristics <br />The drainage basin was divided into four areas for the design of the undisturbed drainage <br />ditches. Soil information was obtained from the Soil Survey of La Plata County Area, <br />Colorado, Soil Conservation Service, USDA. <br />• <br />National King Caa[, LLC. <br />King Mine L! <br />May 2006 <br />Page 1 <br />