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Appendix M (i) - Existing Surface Water Control Features <br />• <br />• <br />• <br />The Division has requested through the review process of TR-11 ,that the operator submit <br />design drawings or text and sizing calculations for all ditches, diversions and culvert erosion <br />protection measures for the features which existed prior to mine permitting. <br />DITCHES <br />The ditches along the haul road were installed during mine road construction and have been <br />functioning property for nearly twenty years. These ditches are typically v -shaped along the <br />inside edge of the road. the ditches are between one and three feet deep and have top width of <br />from two to six feet. The bottoms of the ditches are armored with rock and gravel to prevent <br />erosion of the ditch bottom. During the life of the ditches they have functioned properly. The <br />configuration of ditches and the road is as shown below <br />2' to 6' HIGH BERM <br />In conjunction with the ditches, the road surface and berm shown above are available to <br />contain any high flow events that may exceed the capacity of the ditches. <br />EROSION PROTECTION <br />The inlet of each culvert has a sediment trap working in conjunction with the ditches to <br />DRCH CUiSLOPE <br />SHDNANG BENCH <br />USED IN SOME AI2E0.S <br />control contributions of sedimentation that may occur because of water handling on the road. <br />These traps are typically five to twelve feet wide and fifteen to twenty five feet long. The traps <br />have been, modified overtime to increase their effectiveness. The current configuration is a <br />ramp from the inside edge of the road that slopes toward the culvert and is at least two feet <br />below the culvert it its end. This allows any water flowing from the ditch into the trap to stow <br />down enough to drop any coarse sediment that may be entrained within the water flow. The <br />clarified water is then discharged through the culvert, minimizing any chance for culvert <br />plugging. The traps are cleaned as the sediment approaches the bottom of the culvert. My <br />material recovered from the trap is stored on the mine bench along wlth the haul road <br />sloughage material as permitted by the minor revision approved by the Division on May 7,1984. <br />MU VOL. V <br />PAGE-13 <br />12-9-96 <br />