Laserfiche WebLink
• 2.05.6 <br />AW -15 has been dry during all monitoring events. <br />The average conductivity at the upstream North Fork of the Gunnison River <br />monitoring station for the baseline period (2008 AHR) is 180 umhos /cm. The <br />following table presents the estimated affect the coal pile and gob pile leachate will <br />have on the quality of water in the North Fork of the Gunnison River at low flow: <br />PHC North Fork of the Gunnison River <br />• <br />• <br />AW -4 <br />AW -5 <br />AW -6 <br />AW -11 <br />AW -12 <br />AW -16 <br />AW -17 <br />Min <br />2900 <br />3100 <br />3300 <br />480 <br />485 <br />740 <br />200 <br />Max <br />5300 <br />6800 <br />5600 <br />1480 <br />760 <br />740 <br />272 <br />Average <br />3786 <br />5464 <br />4555 <br />929 <br />609 <br />740 <br />236 <br />Gob Pile Leachate 2 <br />1190 <br />1190 <br />1190 <br />1190 <br />1190 <br />1190 <br />1190 <br />AW -15 has been dry during all monitoring events. <br />The average conductivity at the upstream North Fork of the Gunnison River <br />monitoring station for the baseline period (2008 AHR) is 180 umhos /cm. The <br />following table presents the estimated affect the coal pile and gob pile leachate will <br />have on the quality of water in the North Fork of the Gunnison River at low flow: <br />PHC North Fork of the Gunnison River <br />• <br />• <br />Based on a combined 55.6 gallon per minute flow rate through the coal stockpile and <br />gob pile, the potential impact to the North Fork of the Gunnison River that may result <br />from alluvial ground water migration is minimal as shown above. Additionally, the <br />actual leachate flow through the gob piles is likely to be minimal considering a curve <br />number in excess of 90 is used to predict surface run -off. The conductivity of the <br />alluvial well water is greater than the predicted leachate that could impact the wells <br />except for AW -16 and AW -17. <br />Predicted based on conductivity measurements from Upper B -Seam samples of roof, <br />floor and interburden. <br />TR -64 2.05-75 09/09 <br />/► PP2ov6b <br />I �- �2- 8/aq <br />Flow gpm <br />Flow (cfs) <br />Conductivity (umhos /cm) <br />North Fork <br />11,220 <br />25.00 <br />180 <br />Gob Leachate Discharge <br />50.9 <br />0.11 <br />1190 <br />Coal Pile Leachate <br />4.7 <br />0.01 <br />505 <br />Combined Flow <br />11,275.6 <br />25.12 <br />184.7 <br />Based on a combined 55.6 gallon per minute flow rate through the coal stockpile and <br />gob pile, the potential impact to the North Fork of the Gunnison River that may result <br />from alluvial ground water migration is minimal as shown above. Additionally, the <br />actual leachate flow through the gob piles is likely to be minimal considering a curve <br />number in excess of 90 is used to predict surface run -off. The conductivity of the <br />alluvial well water is greater than the predicted leachate that could impact the wells <br />except for AW -16 and AW -17. <br />Predicted based on conductivity measurements from Upper B -Seam samples of roof, <br />floor and interburden. <br />TR -64 2.05-75 09/09 <br />/► PP2ov6b <br />I �- �2- 8/aq <br />