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Alluvial Valley Floor Findings with Regard to Material Damage to Water Quality and <br />Quantity <br />As mentioned previously, the Munger Mine will be developed into portions of four drainage <br />basins. The surface disturbance will occur only within Munger Canyon and East Salt Creek. <br />The greatest potential for diminution of water quality and quantity would be attributable to <br />the area of surface disturbance. <br />The surface disturbance in Munger Canyon proposed in the initial five-year permit will be <br />comprised of the mine bench, the waste disposal pile and haul roads leading to the portal <br />area. These disturbances will affect approximately 35 acres. The surface disturbance along <br />and adjacent to East Salt Creek consists of the Central facilities area, coal processing waste <br />pile, conveyor system and interconnecting access road which will increase the disturbed area <br />to 122 acres. <br />With respect to surface water quality, a portion of the operation is required to be contained <br />within a sedimentation system. Runoff from the mine bench, central facilities area and the <br />two waste disposal piles will be routed through sediment ponds. These areas present the <br />greatest potential for affecting water quality because of the exposure of subsurface materials <br />and the high level of activity associated with these areas. <br />Total suspended sediment concentrations will be minimized by passing water from disturbed <br />areas through sediment ponds which are designed to remove and contain suspended solids. <br />Total dissolved solids concentrations will slightly increase as a result of runoff from the <br />disturbed areas. In all probability, the runoff from most storm events will not result in <br />discharge from the ponds and, therefore, will not affect the total dissolved solids <br />concentration in the receiving stream. <br />If a portion of the operation situated in Munger Canyon experienced a storm requiring <br />discharge from the ponds, the total dissolved solids concentration would probably be diluted <br />by water from undisturbed areas in the natural channel. The disturbed area (35 acres) <br />accounts for approximately seven-tenths of a percent of the drainage area (5,085 acres) of <br />Munger Canyon. This relationship provides a rough estimate of the extent to which dilution <br />would occur. Furthermore, the disturbed area in Munger Canyon comprises five-hundredths <br />of one percent of the total drainage area of East Salt Creek above the confluence with <br />Munger Canyon (67,288 acres). Further dilution would, therefore, occur by the time the <br />runoff from the disturbed area reaches the alluvial valley floor. A similar relationship occurs <br />for the portion of the operation situated along the East Salt Creek drainage. The disturbed <br />area (43.4 acres) accounts for approximately six-hundredths of one percent of the total <br />drainage area of East Salt Creek below the confluence with Munger Canyon (72,373 acres). <br />Of the 35 acres to be disturbed by the portion of the operation situated in Munger Canyon, <br />approximately 8.4 acres is required to be controlled by sedimentation ponds or small area <br />exemption sedimentation controls. The rest of the disturbance will consist of the haul road. <br />The amount of area essentially removed from the drainage of Munger Canyon due to <br />41