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3. The potential for the pond, if constructed, to adversely affect the stability of the <br />river channel or Highway 110 as a result of the flows associated with the 100-yeaz <br />storm event aze negligible. The 100-yeaz flow is still within the channel based on <br />the Flood Boundary and Floodway Map for this azea. SGC's planned work will <br />not change the capacity of the channel. <br />4. SGC's concurs that grasses may not be the appropriate vegetation for most of the <br />floodplain azea that will be exposed upon removal of the tailings. Therefore SGC <br />modifies its plan to use the "Mountain Mix" exclusively to the use of a mixture of <br />grasses and willow shrubs. The ditch banks and river embankment (where the in <br />place material will support grasses) will be planted with the "Mountain Mix". <br />Throughout the rest of the site, particulazly the pond bank if one is constructed, <br />SGC will transplant 100 willow shrubs. <br />5. The outlet is above the normal high water line and the outlet will be armored with <br />rip-rap material (+18"). The liner will be stopped and anchored within the <br />embankment with the rip-rap material protecting the anchor dirt. <br />6. It is uncertain if the groundwater diverter wall will serve any useful purpose and <br />be constructed. If conditions found do not justify the wall (ie groundwater moving <br />preferentially toward the Tailings Pond No.4 toe drain), it will not be constructed. <br />It is possible that lining the diversion ditch will remove much of the source water <br />observed moving towazds the toe drain. <br />If constructed, the wall will be a type of bentonite-soil mixture placed through in- <br />situ drilling mixing techniques or excavator excavation using bentonite slurry <br />ditch stabilization with soil -bentonite mixing and placement to displace the <br />slurry in the trench without creating voids. <br />Please contact me if the above does not satisfactorily answer the adequacy issues in <br />your letter. <br />Sincerely, <br />Qom` <br />Larry Perino <br />Reclamation Manager <br />2 <br />