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• 2.05.6 <br />• <br />poor. Following is a summary field conductivity measurements (umhos/cm) for the <br />period 1997 and 1998. <br /> AW-1 AW-2 AW-3 <br />Min 4000 Dry 2400 <br />Max 9300 Dry 3600 <br />Average 6667 Dry 2933 <br />Coal Pile Leachate' 810 <br />AW-4 810 <br />AW-5 810 <br />AW-6 <br />Min 4300 4300 4100 <br />Max 5700 6800 4900 <br />Average 4900 5878 4456 <br />Gob Pile LeachateZ 4263 4263 4263 <br />Based on a combined ten (10) gallon per minute flow rate through the coal stockpile <br />and gob pile, the potential impact to the North Fork of the Gunnison River that may <br />result from alluvial ground water migration should be virtually non-existent. The <br />conductivity of the alluvial well water is actually greater than the predicted leachate <br />that could impact the wells. The predicted gob pile leachate (5.3 gpm) has an <br />average iron concentration of 332 ppm and average manganese concentration of <br />7.5 ppm. The following table presents the impact gob pile leachate would have if <br />it flowed into the river at the rate of 5.3 gallons per minute. There are no <br />corresponding values available for coal pile leachate. For the purposes of this <br />analysis, it will be assumed the coal pile leachate has the same characteristics as <br />the B-Seam floor coal at the Bear No. 3 Mine, 9 ppm iron and 1 ppm manganese, <br />(ref. Bear Permit, Vol. 1, page 2.04-24a) The iron and manganese values for the <br />river are obtained from the Bowie No. 2 Mine, 1998 annual hydrologic report, <br />average from lower monitoring point. <br />1 Predicted based on conductivity measurement from a coal sample. <br />• Z Predicted based on conductivity measurements from samples of roof, floor and <br />interburden. <br />PR-O6 <br />2.05 - 75 - <br />08/01 <br />IiP~RovEO <br />/~/5 /O L <br />