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Lateral drains were constructed as discussed under the Stability Analysis <br />Section in Lambert and Associates report dated November 10, 2003. Lateral <br />drains consist of a toe drain and bench drains as show on Figure 4 of Lambert's <br />report. Bench drains will be constructed on 50 -foot vertical centers or at any <br />damp spots encountered in the coal mine waste disposal area founding. See <br />Figure 2 for the layout of the lateral 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. <br />See the detail on Figure 1 which shows how the lateral drains will be isolated <br />from the rock under - drains. <br />The run -off and collection ditches are shown on Figure 2. 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 -F4, and D -1721 are; 1) lined with riprap to ensure they <br />are stable; 2) constructed off the fill and; 3) designed to safely pass the run -off <br />from the 100 -year, 24 -hour precipitation event. Upon completion of the gob pile, <br />the East Diversion and West Diversion Ditch #2 will be lined with the rip rap. <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 <br />pile, a bench configuration will be maintained at the contact point between the <br />coal mine waste and the natural ground surface. Thus, run -off from above the <br />pile and below the upper diversion ditches will be directed to the east and west <br />collection ditches by the temporary benches. The temporary benches will be <br />configured the same as the permanent benches. <br />See Appendix B for detailed design information of the run -off and collection <br />ditches. <br />TR -76 - 9 - 11/12 <br />