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supplemental/back-up discharge via 4" diameter pipe through the South Portal conveyor entry <br />concrete seal, has been permanently plugged in association with South Portal area final <br />reclamation in 2007/2008. <br />The Division has granted an exemption from the use of sediment ponds for NPDES discharge <br />points 002 and 016 from underground mine workings because sediments are settled out in <br />abandoned underground workings before being discharged into the Colorado River. Additional <br />ponds and treatment facilities are not necessary for these discharge points to meet the effluent <br />limitations of Rule 4.05.2 and applicable State and Federal water quality standards for receiving <br />streams. <br />B. Diversions and Conveyance of Overland Flow <br />All conveyance structures within the permit area are designed and constructed in <br />accordance with Rule 4.05.3. Permanent diversions above coal mine waste banks are <br />designed and constructed in accordance with Rule 4.09.2(7). Table 13-4 of the application <br />lists all diversion and conveyance ditches along with references to the appropriate exhibits <br />for designs and cross sections. Calculations used to design these structures are given in <br />appendix 13-2 of the permit application. A number of permanent channels or channel <br />segments have been constructed or will be constructed following reclamation of temporary <br />sediment and drainage control facilities at various locations. A segment of the Coal Creek <br />permanent diversion is to be re-constructed following reclamation of Pond 6 and Pond 10, <br />and a final reclamation segment of the Coal Gulch permanent diversion is to be constructed <br />following removal of Pond 11. A permanent reconstructed channel segment has been <br />completed at the North Decline Reclaimed area, with the exception that channel berm <br />breaks will be installed prior to final bond release. Several permanent ephemeral channels <br />are to be constructed across the North Portal reclaimed area following removal of the <br />temporary upper diversion ditch and reclamation of Pond 13. Finally, several permanent <br />drainage channels were constructed in association with the South Portal area reclamation <br />grading. <br />C. Stream Channel Diversions <br />Construction of the Cameo Refuse Disposal Areas involved the installation of a permanent <br />ephemeral stream channel diversion along a segment of Coal Canyon in the vicinity of the refuse <br />areas. A total of approximately 600 feet of the Coal Canyon drainage was diverted. <br />The channel segment was originally constructed with four rock drop structures to minimize <br />erosion along the segment. The channel obstructions caused by the drop structure installations <br />were determined by the Division to be inappropriate, due to the potential for high flow to escape <br />the channel. As a result, modified interim and final designs have been approved. The interim <br />channel was constructed by removing the rock structures and grading the channel segment to a <br />uniform gradient in 2002. The final design provides for re-alignment of the upper segment of <br />the channel section to allow installation of a meander in the vicinity of Sediment Pond 6, in <br />conjunction with Pond 6 reclamation. Designs are located in Appendix 13-2 and channel <br />locations and cross sections are shown on Exhibit 51, 52, 53 and 55. Pursuant to TR-42 <br />approved in 2003, the Division approved the installation of a riprap transition zone at a "nick- <br />point" in a lower segment of the Coal Creek channel, in the vicinity of the former Haul Road 2 <br />.Permit Revision No. 4 21 February 3, 2009