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2.05.6 <br />Leachate from the refuse piles and coal stockpile could also degrade the <br />water quality of the river. The existing refuse piles, southern refuse pile and <br />the coal pile will encompass 2.7, 30.6, 15.8 and 4.9 acres at full capacity <br />respectively. Based on the Upper B-Seam geochemical analysis presented <br />in Volume III, Exhibit 6, the average conductivity of the roof, interburden and <br />floor samples is 1190 and coal is 505 umhos/cm. According to Section <br />2.04.8 the average annual rainfall in the area is 18.5 inches. If all of this <br />rainfall percolated through the piles during the year, the equivalent flow <br />would be 51.6 gallons per minute. In its Cumulative Hydrologic Impact Study <br />for the North Fork of the Gunnison dated September 25, 1992, the DRMS <br />assumed infiltration through a refuse pile is the result of snowmelt and it was <br />estimated 2.8 inches per year would infiltrate during a 60 day period. The <br />equivalent flow for this assumption over the 54.0 acre piles is 50.5 gallons <br />per minute over the 60 day period. The two different leachate production <br />estimates produce similar equivalent flow values. <br />Alluvial wells were installed to monitor groundwater contamination. AW-1, <br />AW-2 and AW-3 are near the coal stockpile. AW-4, AW-5 and AW-6 are <br />near the gob pile No. 1. AW-15, AW-16 and AW-17 are below Gob Pile No. <br />2. The water quality in the wells is poor to good. Following is a summary of <br />baseline conductivity measurements (umhos/cm) for the alluvial wells <br />obtained from the Annual Hydrology Reports. <br />L' <br />TR-54 <br />2.05 - 74 12/08 <br />APPRovED <br />~~,~a~ <br />