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DIVERSION. OF THE THREE PONDS AT THE MINE SITE , TWO ARE <br /> UTILIZED FOR RUNOFF CONTROL (003 & 004 ) AND THE THIRD (002) <br /> IS USED ONLY FOR THE TREATMENT OF MINE WATER. RUNOFF FROM <br /> THE PARKING LOT, STORAGE YARD AND ALL AREAS WEST OF THE <br /> SLOPE EXCAVATION, TRESTLE , AND SILO FLOWS TO POND 003 WHICH <br /> IS LOCATED TO THE NORTH OF THE MINE SITE . RUNOFF FROM THE <br /> SLOPE EXCAVATION . SPOIL DUMPS AND ALL AREAS EAST OF THE <br /> TRESTLE AND SILO, IS CHANNELED INTO POND 004 WHICH IS <br /> LOCATED NORTH EAST OF THE MINE SITE . THE RUNOFF FROM THE <br /> RAILROAD YARDS IS ALSO CHANNELED TO THESE PONDS . WATER FROM <br /> THE SEWAGE TREATMENT PLANT, OF HIGH ENOUGH QUALITY FOR <br /> DIRECT DISCHARGE . FLOWS THROUGH POND 004 . NPDES DISCHARGE <br /> POINTS O02, 003, AND 004 CORRESPOND WITH THE POND NUMBER <br /> DESIGNATIONS FOR EASY IDENTIFICATION. <br /> TABLES 3 AND 4 LIST AND DESCRIBE ALL DRAINAGE AREAS AND <br /> CHANNELS RESPECTIVELY. SETTLEMENT TIMES IN THE PONDS IS <br /> CONTROLLED BY PERFORRATED DRAINAGE RISERS AS WELL AS <br /> MANUALLY OPERATED STOP-GATES AT THE DISCHARGE BOXES . <br /> BECAUSE OF THE MANUALLY CONTROLLED DISCHARGES SHORT- <br /> CIRCUITING OF RUNOFF CAN BE ELIMINATED AND THE ENTIRE RUNOFF <br /> LOAD SUFFICIENTLY SETTLED PRIOR TO DISCHARGE. THE EMERGENCY <br /> SPILLWAYS WILL HAVE MORE THAN ONE FOOT OF FREEBOARD WHEN <br /> PASSING THE PEAK FLOWS OF THE DITCHES FEFDING THE PONDS . <br /> THEY WILL ALSO PASS THE RUNOFF FROM A 25YR-24HR STORM EVENT <br /> WITH AN EVEN GREATER FREEBOARD. THE POND DISCHARGE POINTS <br /> HAVE CONCRETE BOX STRUCTURES AND RIP-RAP DISPERSION BASINS <br /> 6 <br />