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Water Quality Changes Over Time in Above-Drainage Upper Freeport and Pittsburgh Coal Mines in West Virginia Ben Mack, Jeff Skousen, Louis McDonald, and Dorothy Vesper West Virginia University

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- Major pollutant - Pyritic rocks

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Mine type Above-drainage vs. Below-drainage

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Younger (1997) Below-drainage years Below-drainage years - Type 1 - initial flush of mine - first 10 years after mine closure - Type 2 - continued pyrite oxidation Below – drainage mines Below – drainage mines - 25 years between samples - pH from 3.0 to 6.1

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Above – drainage mines Above – drainage mines - 25 years between samples - pH from 3.0 to 3.5 Lambert and Dzombak, 2000

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Annual % decrease of 2 and 3% from the previous year

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Determine changes in acidity concentrations of 40 above- drainage, underground mines over 38 years using decay rates Determine changes in acidity concentrations of 40 above- drainage, underground mines over 38 years using decay rates

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Historic sampling EPA sites EPA sites WV DNR - 20 sites WV DNR - 20 sites WVU - 40 sites WVU - 40 sites WVU - 40 sites WVU - 40 sites Graphs of acidity vs. time for 6 Pittsburgh and 34 Upper Freeport (UF) sites Graphs of acidity vs. time for 6 Pittsburgh and 34 Upper Freeport (UF) sites

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Acidity collection

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Compare to T&T #2 Compare to T&T #2 - Closed in Different decay rate?

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Sitesn Pittsburgh6-83%-58%87% -74%

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Sitesn UF > %-44%10%-81% UF %-35%5%-79% UF %-4%-42%-70% Increasing UF144%47%-31%46%

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Sitesn UF > %-44%10%-81% UF %-35%5% -79% UF %-4%-42%-70% Increasing UF144%47%-31%46%

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Sitesn UF > %-44%10%-81% UF %-35%5%-79% UF %-4%-42% -70% Increasing UF144%47%-31%46%

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Sitesn UF > %-44%10%-81% UF %-35%5%-79% UF %-4%-42%-70% Increasing UF 144%47%-31% 46%

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Groups n mg/L as CaCO Pittsburgh UF Groupn Pitts %-1.4%1.4% -2.1% UF %-1.8%-5.0% -2.1% % decrease of acidity per year

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% of initial concentration vs. time (exponential decay) Exponential decay: C/C 0 =e -kt C/C 0 =e -.02t C/C 0 =e -.05t C/C 0 =e -.10t

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Pitts. exp. decay constant (k) = Estimated initial acidity = 9,113 mg/L as CaCO 3 (3.86 relative acidity) 2006 sampling 1968 Sampling

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UF exp. decay constant (k) = Estimated initial acidity = 5,413 mg/L as CaCO 3 (4.01 relative acidity)

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Acidity at time of closure = 1,128 mg/L as CaCO 3 T&T exp. decay constant (k) = Increased decay rate due to first flush

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Conclusions Pittsburgh and UF mines showed a 2.1% annual decrease in acidity Pittsburgh and UF mines showed a 2.1% annual decrease in acidity

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Pitts. mines Pitts. mines - Pitts. decay rate constant = Estimated initial acidity = 9,113 mg/L as CaCO 3 (3.86 relative acidity) UF mines UF mines - UF decay rate constant = Estimated initial acidity = 5,211 mg/L as CaCO 3 (4.01 relative acidity)

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T&T #2 T&T #2 - T&T decay rate constant = Increased decay rate due to first flush first flush

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Questions?

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