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• EXECUTIVE SUMMARY & ENGINEER'S CERTIFICATION <br />Exhibit 66 was prepared to update the Mine Water Control Plan at West Elk Mine to reflect the <br />construction of a new sedimentation pond (Pond MB-5E) and associated work on ditches and <br />culverts necessary to direct water to the new pond. Pond MB-5E will replace MB-5, and will <br />serve the drainage areas that formerly reported to Ponds MB-1 (to be converted to freshwater <br />storage, FW-2), MB-2R (to be filled/decommissioned), and MB-5 (to be expanded/replaced by <br />MB-5E). This exhibit updates the one produced in November 2008 to reevaluate the September <br />1993 Mine Water Control Plan. The 2008 revision presented an updated SEDCAD+ analysis of <br />the mine's surface water collection and treatment system, based on field inspections of the <br />existing ditches and culverts, and also reflected proposed repairs to be constructed from Fall <br />2008 through Summer 2009. The analysis was based on previous analyses provided by West <br />Elk Mine, and field confirmation of site conditions. Survey information from the previous design <br />analyses was accepted, but not checked. <br />The current analysis includes the watersheds and drainage networks reporting to Ponds MB-3 <br />and MB-5E, and the two cleanwater diversions at MB-5E. Ponds MB-1, MB-2R, and MB-5 are <br />no longer part of the Mine Water Control Plan, and related materials should be removed from all <br />current copies of the plan. Materials submitted in 2008 remain current for Ponds NSSA, RPE, <br />and SG-1; cleanwater diversion outfalls not located at MB-5E; and outfalls to natural drainages <br />within Sylvester Gulch. Updated site maps and drainage network diagrams for MB-3 and MB- <br />5E are included. No changes have been made to existing previously approved Small Area <br />Exemption demonstrations, or to Pond MB-4. <br />With consideration to applicable drainage principles and generally accepted engineering <br />• standards and procedures, the analysis submitted provides for the drainage and stormwater <br />flow from the subject site areas to be in accordance with applicable requirements, and to the <br />best of my knowledge, represents good standard engineering practice. The drawings presented <br />herein are for permitting purposes only (not for construction). <br />Peter E. Kowalewski, PE <br />