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reclaimed mine on surface water quality. Seneca Coal Company's predictions <br />of the magnitude of these impacts is discussed below. <br />Sediment Loading <br />All runoff from azeas disturbed during the life of mine will pass through one <br />of Five sedimentation ponds prior to leaving the permit area. Discharges from <br />the ponds will be required to meet NPDES effluent limits, and should, <br />therefore, not contribute additional suspended solids to stream flows neaz the <br />permit area. <br />Following reestablishment of drainage channels and vegetation during <br />reclamation, more runoff from the mine azea will occur. However, sediment <br />loads in that runoff should be no larger than those currently coming from the <br />permit area. <br />Quantity of Surface Flows <br />The largest peak flow recorded in Armand Draw during baseline data <br />collection was 0.585 cfs. The presence of a sediment pond in Armand Draw <br />will attenuate peak flows in that drainage during mining. After mining, flows <br />in Armand Draw will increase due to establishment of spoil springs and <br />additional runofffrom the reclaimed azea. Spoil springs are projected to add <br />approximately 0.073 cfs of base flow to Armand Draw. <br />Spoil springs in Armand Draw and the Pond 11 drainage will add year-round <br />base flow to Grassy Creek. These spoil spring contributions are projected to <br />increase mean flows during irrigation season (June 1-September 30) in <br />Grassy Creek from 0.25 to 0.37 cubic feet per second downstream from the <br />Yoast Mine. <br />Spoil springs aze projected to add approximately 0.159 cfs of base flow to <br />Sage Creek during irrigation season (June 1 -September 30). These spoil <br />spring contributions aze projected to increase mean flows during the irrigation <br />season in Sage Creek from 0.259 to 0.418 cfs. <br />Yoast Mine 29 February 28, 2006 <br />