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4 - <br /> Provide for construction and maintenance of siltation structures at <br /> culvert inlets and switchback ditch outlets (similar to BAT ponds <br /> at Arctic Circle) . Where warranted and where access and terrain <br /> allow, provide for construction and maintenance of larger siltation <br /> basins or sediment ponds , which would be designed and maintained to <br /> provide sufficient settling time for water to meet applicable <br /> settleable or suspended solids limits prior to discharge . <br /> Locations where large siltation basins or sediment pones should be <br /> considerec include the following: <br /> Existing BAT ponds below Mine 1 . <br /> - Bowl shaped erosional ''blow out" on Drainage B-5 at approximate <br /> Sta. 30 + 00 on Road B. <br /> Drainage below B-3 culvert outlet, adjacent to the small area <br /> exemption bench south of the Rock tunnel area. <br /> Meadow below F-3 curve adjacent to Mine 3 lower bin pad . Drainage <br /> from RC-4 ditch outlet could be routed through a pond at this <br /> location. <br /> Lower end of long meadow on Road F. Pond would treat drainage from <br /> a significant segment of road and road related erosion. Pond site <br /> is adjacent to road curve just above proposed culvert F-3N. <br /> Problem: Excessive erosion or sedimentation from road cuts and fills (see <br /> NOV C-=1-018) <br /> Contributing factors : <br /> - Steep slopes , unstable soils <br /> - unsatisfactory vegetation <br /> - Improper drainage <br /> - Slope instability (lower road F) <br /> - Berm material pushed over downslope <br /> Possible approaches : <br /> - Revege:ate slopes amenable to seeding. <br /> - Construct siltation structures where feasible. <br /> - Ccnstruc: and maintain straw bale dikes or silt fence along base of <br /> any r'oac fill slopes which drain directly into a water course with <br /> no vegetative buffer between fill and stream. <br /> - Reduce and revegetate over-steepened fill slope crests . <br /> - Avoid pushing berm material over outslope. <br /> - Develop stabilization/reclamation plan based on geotechnical <br /> evalua:ion of Road F landslide . <br /> Problem: Maintenanceireclamation of Licht use roads serving ancillary <br /> facilities ane monitoring locations . <br /> A number of poorly maintained light use roads exist within the <br /> permit area. A11 such roads which are currently used or which have <br /> been used by Mid-Continent since 1977 need to be documented within <br /> the permit and depicted on aocrooriate permit maps . Drainage <br /> c:nz-cl , maintenance and reciamation plans for such roads and <br />