2013-09-27_REVISION - M1979094HR (3)

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i n �a 2�. . ' TT, ac `yd. 13.94 ac qA44c G,4 Figure 8. Aerial Photograph Showing Sub - Basins N -A, N -B, N -C, N -H, and N -1 Reporting to Valley Floor South of Soil Stockpile and Planned Open Pit Waste Rock Pile 4.2 Sub - Basins and Stormwater Routing on the JD -7 Mine Site Twelve sub - basins were delineated covering disturbed or reclaimed areas of the JD -7 Mine site. The sub - basins were delineated according to how run -off flows to individual conveyance structures (culverts or ditches) or to segments of individual drainage structures that receive increasing runoff along their length. The sub - basins contributing runoff to the site are shown in Figure 10 and listed in Table 11. Table 11. Sub - Basins Within the JD -7 Mine Permit Area Sub -Basin Area Area Type Description / Type (ft) (acres) D -1 3,582,810 82.25 Disturbed Open pit D -2 36,530 0.84 Disturbed South of access road EE17 to culvert CV2 D -3 814,950 18.71 Disturbed South of access road EE17 to culvert CV2 D -4 153,010 3.51 Disturbed South of access road EE17 to culvert CV3 D -5 37,690 0.87 Disturbed North of open pit to culvert CV 1 D -6 104,090 2.39 Disturbed Mine yard area D -7 950,630 21.82 Disturbed East portion of open pit waste rock pile D -8 279,790 6.42 Disturbed Southeast portion of open pit waste rock pile D -9 607,030 13.94 Disturbed Southwest portion of open pit waste rock pile D -10 1,179,200 27.07 Disturbed Northwest portion of open pit waste rock pile D -16 67,290 1.55 Disturbed Underground- waste -rock pile and wastewater treatment ponds D -17 18,540 0.43 Disturbed Small southwest portion of underground- waste -rock pile Sub -basin D -1 encompasses the existing 82.25 acre JD -7 open pit and was modeled with a curve number of 80, representing sagebrush with grass understory in poor hydrologic condition. The open pit is self - draining, and stormwater runoff from the pit walls and floor flows northwest toward an ephemeral pond on 4149A.130926 Whetstone Associates