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the coal mine waste disposal area founding. See Figure 2 for the layout of the lateral <br />drains. No damp spots were encountered. <br />The lateral drains are not in hydraulic communication with the rock under -drains, <br />since they might inadvertently permit the infiltration [Rule 4.09.1(13)] of water. See <br />the detail on Figure 1 which shows how the lateral drains will be isolated from the <br />rock under -drains. <br />The run-off and collection ditches are shown on Figure 2. Run-off from the benches <br />will be directed to the east and west to collection ditches. The east and west <br />collection ditches D -F4, and D -F14 are; 1) lined with riprap to ensure they are stable; <br />2) constructed off the fill and; 3) designed to safely pass the run-off from the 100 - <br />year, 24-hour precipitation event. <br />Upon approval of TR -89, the East Diversion ditch will be re -located higher up on the <br />hillside. The new diversion channel could be constructed in a stair -stepped <br />configuration and the construction will be in phases as the elevation advances up the <br />hillside. Before gob is placed in the current east diversion ditch, a new channel will <br />be cut above the level of the first gob placement elevation. As the gob placement <br />advances, a new diversion ditch will be cut above the anticipated gob level. At all <br />times, a diversion channel will be in place above the level of the gob. <br />Temporary upper diversion ditches and the east and west collection ditches were <br />constructed prior to placement of coal mine waste. During construction of the pile, a <br />bench configuration will be maintained at the contact point between the coal mine <br />waste and the natural ground surface. Thus, run-off from above the pile and below <br />the upper diversion ditches will be directed to the east and west collection ditches by <br />the temporary benches. The temporary benches will be configured the same as the <br />permanent benches. <br />Runoff from the TR -98 borrow areas will be either directed to Pond F (Borrow area <br />1), or, to a silt fence or waddle (borrow area #2). Sedimentation control will not be <br />required until prior to the disturbance is created by the borrow areas. Please see <br />Figure 2 for sedimentation control details. <br />See Appendix B for detailed design information of the run-off and collection ditches. <br />TR -98 _10- 04/15 <br />