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• 2.05.6 <br />poor. Following is a summary field conductivity measurements (umhos/cm) for the <br />period 1997 through 2002. <br /> AW-1 AW-2 AW-3 <br />Min 3840 4030 2160 <br />Max 8610 4030 3370 <br />Average 5658 4030 2701 <br />Coal Pile Leachate' 505 505 505 <br /> AW-4 AW-5 AW-6 <br />Min 3040 4660 3670 <br />Max 9490 6560 5130 <br />Average 4526 5785 4312 <br />Gob Pile Leachate2 1190 1190 1190 <br />Based on a combined 37.8 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 minimal. The conductivity of <br />the alluvial well water is actually greater than the predicted leachate that could <br />impact the wells. The predicted gob pile leachate, based on the Upper B-Seam roof <br />and floor analyses presented in Volume Ill, Tab 6, has an average iron <br />concentration of 26.8 ppm and average manganese concentration of 1.9 ppm. The <br />predicted coal pile leachate based on the Upper B-Seam Coal analyses presented <br />in Volume III, Tab 6, has an average iron concentration of 8.6 ppm iron and average <br />manganese concentration of 0.1 ppm. The iron and manganese values for the river <br />are obtained from the Bowie No. 2 Mine, 2002 annual hydrologic report, average <br />from lower monitoring point. The following table presents the impact gob pile <br />leachate and coal pile would have if it flowed into the river at the rate of 4.4 and 0.6 <br />gallons per minute respectively. <br />Predicted based on conductivity measurement from an Upper B-Seam coal sample. <br />• Z Predicted based on conductivity measurements from Upper B-Seam samples of roof, <br />floor and interburden. <br />TR-30 <br />2.05 - 75 - <br />11 /03 <br />AP/P~RovEp <br />',( _3/0 y <br />