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Ms. Paige Seville -2- December 17, 1984 <br />~~ 6. Topsoil salvaging at the access road along with buffer zone widths <br />needs to be adressed. <br />DRAINAGE <br />^ 1. All surface drainage from the area above the refuse pile and the crest <br />Br~'.h and face of the pile needs to be diverted in accordance with Rule 4.09.2(7) <br />(See Rule 4.10.3(2)}. This rule requires diversions designed to the 100 year <br />event. Designs and calculations verifying compliance need to be provided. <br />2. The ditch flow velocities indicated on page 45 show 9.1 and 8.2 feet <br />~~ .per second. The designs should indicate what channel lining will be used to <br />handle such a high velocity. Supporting calculations should be included. <br />3. Two "lined ditches" are indicated on map 002 at the southeast and <br />~~ southwest part of the pile. Designs need to be provided for these ditches to <br />indicate how runoff from the terraces will be routed safely down the pile. <br />The designs should consider 100 year event, appropriate riprap size and <br />gradation, filter blanket, capacity, and appropriate discharge point. <br />Structural controls such as culverts should not be used. <br />4. Ditches need to be provided on terraces to safely route drainage off <br />~~~ the pile; designs need to be provided. Flow velocities need to be low enough <br />to prevent scouring but high enough to minimize ponding and siltation. • <br />~~~ 5. Terraces are proposed at 30 feet wide. Rule 4.14.2(2)(a) puts 20 foot <br />wide limitation on terraces unless the applicant can demonstrate a need for <br />wider terraces. Please provide justification for your terrace width. <br />6. Fhe application needs to specify which ditches are to remain as <br />permanent and justify their need. All other ditches need to be removed and <br />their removal costs included in the bond. <br />~ 7. Grades on the very top of the refuse pile should be indicated to show <br />~' whether and how the pile top will drain positively and without erosion of the <br />pile face. <br />8. A perimeter ditch may be needed along portions of the base of the pile <br />to collect runoff and discharges from the terraces. Without a ditch some <br />erosion of the toe of the pile may occur. Please address this concern. <br />9. The construction of the pile will result in increased surface runoff, <br />~ groundwater discharge from the underdrains, and increased drainage area routed <br />~-~' to the proposed 36 inch~l/2 C.M.P. (culvert). The application needs to <br />demonstrate that the half culvert can handle the worst case flow situation. <br />ROADS <br />1. The Division classifies your proposed road as an access road as opposed • <br />to a haulroad which is stated in the application. The reason is that no coal <br />will be hauled on the road, only waste. <br />2. Page 52 of the application states that the road east of the portal may <br />be used as an alternative access to the site. The Division cannot. approve of <br />