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~, 2:05.6 <br />PHC North Fork of the Gunnsion River <br /> Flow gpm Flow cfs Iron (ppm) Mn (ppm) <br />North Fork 11,220 25 0.21 0.09 <br />Gob Leachate Discharge 46.9 0.11 26.8 1.9 <br />Coal Pile Leachate 4.7 0.01 8.6 0.1 <br />Combined Flow 11,273.6 25.12 0.292 0.095 <br />Based upon the above calculation, if leachate from the gob and coal piles reached <br />the North Fork of the Gunnison River, it will not have a significant impact on the <br />quality.of water in the river. <br />The predicted pH of the gob pile leachate and coal, based on the data presented in <br />Volume III, Tab 6, are 9.2 and 9.3 respectively. The North Fork of the Gunnison <br />River has pH values in the 8.3 range. If the entire 51.6 gpm of leachate entered the <br />River, the pH of the River would increase from 8.3 to 8.304 which is insignificant. <br />Flooded mine workings could also impact the water quality in the area. When the <br />mines are sealed they will slowly fill with water. Although no data for permeability or <br />transmissivity of the saturated portions of the coal bearing member of the Mesaverde <br />Formation are available within the permit area, the experience by others (Brooks, <br />1983) suggests the Mesaverde Formation transmits little water. Therefore, the <br />abandoned mine workings would not be expected to transmit water to the <br />surrounding strata. Based on the above discussion, if the mine workings fill with <br />water and discharge through the portals, the impact on the North Fork of the <br />Gunnison River would be less than or equal to the mine water discharge analysis <br />presented above. <br />• <br />TR-54 2.05 - 751 06/08 <br />A.PFRovED <br />~/l ~~flq <br />