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As explained in Section 2.04.7, the Bowie No. 2 Mine was experiencing an <br />inflow of approximately 700 gpm. Recent mine water quality analysis are <br />shown above in section 2.05.6(3)(a)(iv). For the purposes of this PHC a <br />worst case mine inflow/discharge of 1,000 gpm from Outfall 006 is utilized. <br />Flow from outfall 006 need only travel a short distance to enter a highway <br />culvert and join the North Fork of the Gunnison River. See Map 41, Mine <br />Discharge Pipe Alignment. The heavily vegetated water course from Outfall <br />006 to the highway culvert will eliminate the possibility of sediment entering <br />the North Fork of the Gunnison River due to erosion. Since the mine <br />discharge will mix with the River water in a relatively short distance, there are <br />no lands, river banks, structures, alluvial valley floors or prime farm land on <br />either side of State Highway 133 that potentially may be adversely affected <br />by the mine water discharge quantity or quality. <br />The average TDS and total recoverable Manganese measurements at the <br />upstream North Fork of the Gunnison River monitoring station for the <br />baseline period (2007 AHR) are 130 and 0.015 mg/I respectively. The <br />average iron measurement at the upstream North Fork of the Gunnison River <br />monitoring station for the baseline period (2007 AHR) is 0.09 mg/I. The <br />following table presents the estimated affect the average mine water quality <br />(page 2.05-70i) will have on the quality of water in the North Fork of the <br />Gunnison River at low flow: <br />PHC North Fork of the Gunnison River <br />Flow Flow TDS Manganese Iron <br />Gpm cfs mg/I Trec. mg/I Trec, mg/I <br />North Fork 11,220 25 130 0.015 0.09 <br />Mine Discharge 1,000 2.2 2,838 0.037 2.43 <br />Combined Flow 12,2201 27.21 3521 0.017 0.28 <br />Based upon the above calculations, the mine discharge into the North Fork <br />of the Gunnison River will not have a measurable impact on total recoverable <br />manganese or total recoverable iron in the river. TDS values in the river <br />would increase under rare low flow conditions. <br />The pH of the North Fork of the Gunnison River varies from 7.5 to 8.8 <br />according to the 2007 AHR. The average pH of the mine discharge water is <br />8.4. Therefore, the mine discharge water should not adversely affect the pH <br />in the North Fork of the Gunnison River. See the following table for addition <br />PHC analysis. <br />PR -14 2.05-117 03/14 <br />