Laserfiche WebLink
1.0 Scope of Work <br /> <br /> <br /> <br />The site earthwork drawing dated August 2008, and titled "Sediment Control Plan & <br />Watershed" showing proposed earthwork and drainage system for the King II Mine was <br />given to Environmental Industrial Service (EIS) by Fleming Engineering. EIS was <br />instructed to determine if the sediment pond as constructed and the culverts and ditches <br />would be adequate to meet the requirements of the Colorado Mined Land Reclamation <br />Board for Coal Mining Regulations. <br />2.0 Mine Drainage Map <br />The drainage map for King II Mine is divided into two (2) drainage basins. Basin "A" is <br />located in the east fork of the mine site and Basin "B" is located in the west fork of the <br />mine site. These two basins were subdivided into undisturbed areas and disturbed <br />areas for determining the amount of sediment being routed to the sediment pond. <br />These basins were further divided into small drainage areas to determine the amount of <br />runoff for the various culverts and ditches. <br />SEDCAD 4 from Civil Software Design was used to calculate the amount of runoff and <br />sediment loads from the areas. <br />2.1 Treatment of Runoff <br />t Runoff from the from Basin "A" and Basin "B" (25.51 acres) is directed to the sediment <br />pond, which is located south of the surface facilities. It is estimated that approximately <br />55% of the of the area will be disturbed (14.03 acres). The remainder of the property <br />' (11.48 acres) is located in steep areas and will not be disturbed from construction <br />activities. The sediment pond will handle the runoff from the total 25.51 acres. <br />3.0 Hydrology <br />Peak discharge was calculated using the storm event of 10yr-24hr. This event is 2.20 <br />inches of precipitation. <br />4.0 Structures <br />The sediment pond will contain and treat the volume from a 10yr-24hr event. The runoff <br />from the 10yr-24hr event is calculated to be 1.68 acre-feet. There is sufficient capacity <br />above the recommended sediment level to contain a 10yr-24hr event without overflowing <br />' the principal spillway. <br />The ditch lengths and slopes were determined by using Drawing "Sediment Control Plan <br />and Watershed". The ditch design information was obtained by using Drawing "Details" <br />' for the width of the ditch bottoms, side slopes and whether the ditch was trapezoidal or V <br />shaped. Fleming Engineering also provided this drawing. The ditches were designed as <br />erodible ditches using a material of shales and hardpan. <br />2