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h) All principal spillways will have 2 seep collars installed within the dam which will be at <br />least 2x the pipe diameter. All dam fill will be compacted around the seep collars and <br />principal spillway pipe to 90% of the maximum dry density of the fill material. <br />i) The emergency spillways will be a rip -rap lined trapezoidal channel of 10 feet bottom <br />width and 2:1 sideslopes. <br />k) Attachment 2.05.3(3) -15 demonstrates that the given materials on site have been <br />tested for suitability in constructing pond embankments and that the long term slope safety <br />factors exceed 1.3 in all cases, given the pond design parameters outlined above and in the <br />Attachment. For this reason, no individual slope stability analyses are presented for the <br />ponds. <br />Pit dewatering may occur year round or during portions of a year. The dewatering process <br />will be a sporadic operation - controlled, occurrence depending on various factors which may <br />include the location of the pit inflows, the location of standing water in the pit, or the location <br />within the pit of the overburden and coal removal operations. When pit dewatering is <br />required, the anticipated dewatering rate will be in the range of one to two cubic feet per <br />second or less. Prior to Pond 011 being built, all pit dewatering discharges were directed to <br />Pond 007, which was the main pond for the western portion of the permit area. Direct pit <br />pumping into Pond 011 now occurs. These procedures have been applied for in WFC's <br />NPDES Permit, which is similar to Permit CO- 0000213 for Ponds 007, 008 and 009. The <br />revised NPDES Permit is enclosed in Attachment 2.05.3(3) -18. <br />The mine pit dewatering shifted from Pond 007 to Pond 011 in June 2008. It is anticipated <br />that pit dewatering will then be transferred from Pond 011 to Pond 013 sometime in late <br />2010 or beginning of 2011. Pond 011 is covered under a NPDES Discharge Permit. <br />Pit dewatering will have an insignificant impact on Pond 011. The flow rate of one to two <br />cubic feet per second or less compared to the designed 25 -year, 24 -hour peak inflow rate of <br />33.5 cubic feet per second is not significant. This is demonstrated in detail in Attachment <br />2.05.3(3) 2.05.3(3) -14 POND 11 ENGINEERING AND HYDROLOGIC DESIGN. In addition, <br />pit water high in suspended solids will be allowed to set for a period of time so the solids are <br />allowed to settle out of the water and will remain in the active pit area. <br />Ponds 009, 011, 012, 013, 014, and 015 will be maintained until: <br />(Revised ,tune 2010) 2.05.3(3) -14 <br />