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<br />EXHIBIT 7, ITEM 14, PART O <br />SECTION 16 POND DITCH EXTENSION <br />The location of the Section 16 Pond is presented on Map 41. This analysis was originally <br />completed as the Section 16 Side collector ditch was lengthened for mining activities associated <br />with the Section 16 Pit extension under TR-65. The collector ditch was lengthened a second <br />time under TR-71 to direct additional areas to the Section 16 Pond. The profiles of the <br />associated ditches are presented on Map 33A. Channel design of these drainage channels is <br />provided in Exhibit 7, Item 14. Exhibit 7, Item 140, Figure 1 shows the breakdown of drainage <br />areas and hydrologic conditions for this ditch and sediment pond, and Figure 2 provides a <br />diagram of the structures and networking. Longer term, the Section 16 Pit extension area will be <br />mined under the South Taylor mine plan, and associated hydrologic design for those facilities are <br />presented in Exhibit 7, Item 20. <br />The following pages present the results of a single SEDCAD run under the worst case hydrologic <br />conditions during mining for the 10 year, 24 hour design storm. This design event generated <br />about 80 . cfs of peak runoff and a total runoff volume of about 6.6 acre-feet under these <br />conditions. The 25 year, 24 hour design event is also provided behind the ten year analysis. <br />This analysis is provided to verify that the storm event can be safely passed through the <br />emergency spillway. This larger event produced a total runoff volume of about 10.3 acre feet <br />and results in a flow depth of 0.73 feet through the emergency spillway. <br />Volume 2E contains several other SEDCAD runs for the Section 16 Pond for the postmining <br />case, including a case using the 100 year event for spillway adequacy. <br />Exh. 7-140-1 Revision Date: 7/07/08 <br />Revision No.: TR-71 <br />