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Water Control Measures <br />Rule 4.09.1(13) requires that an appropriate underdrain be installed if seeps, springs <br />or waterways, natural or manmade, are in the coal waste disposal footprint area. A <br />June 2013 inspection of the site found that seepage from the Fire Mountain Canal <br />had surfaced in the upper diversion ditch. Wet areas were also noted below the <br />upper diversion ditch. The seepage did not cause any perceptible flow. The design <br />of a rock subdrainage system is detailed below. <br />During a July 2015 inspection of the site, another seep from the Fire Mountain Canal <br />was discovered north of the East Drying area. Much like the seep discovered in <br />2013, there is no perceptible flow. Currently, gob placement south of the seep is for <br />drying purposes only. A subdrainage system will be installed as the drying area is <br />cleaned out and prior to final gob placement. The design of the rock subdraiange <br />system is the same as West Underdrain and is detailed below. <br />The run-off and collection ditches are shown on Map 21. Run-off from the <br />benches will be directed to the east and west to collection ditches. The east and <br />west collection ditches D -J11 and D -J9 are; 1) lined with riprap where necessary <br />to ensure they are stable; 2) constructed off the fill and; 3) designed to safely <br />pass the run-off from the 100 -year, 24-hour precipitation event. <br />See Appendix B for detailed design information of the run-off and collection <br />ditches. <br />As noted previously, there will be two configurations in the permit; an operations <br />configuration and a full build out configuration: The full build out configuration will <br />be included at the end of Appendix B beginning on page XX. The Operations <br />configuration is the current configuration and will be revised as needed to reflect <br />the changing in field conditions. <br />Sedimentation Pond <br />Sediment Pond J was modified so it will contain the additional run-off from the <br />coal mine refuse disposal area. The sediment pond and the general drainage <br />plan for the waste disposal site were prepared by Tammerin Kae Stover -Bishop, <br />Colorado Professional Engineer, No. 43402. See Map 22-J. <br />Volume XI <br />TR -105 - 5 - 09/15 <br />