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

Water Quality Changes Water Quality Changes Over Time inOver Time in

Above-Drainage Above-Drainage Upper Freeport and Upper Freeport and

PittsburghPittsburgh Coal Mines Coal Mines in West Virginia in West Virginia

Ben Mack, Jeff Skousen, Ben Mack, Jeff Skousen, Louis McDonald, and Dorothy VesperLouis McDonald, and Dorothy Vesper

West Virginia UniversityWest Virginia University

- Major pollutant- Major pollutant

- Pyritic rocks- Pyritic rocks

Mine type

Above-drainage vs. Below-drainage

Younger (1997)Younger (1997)

Below-drainage - 10 - 40 yearsBelow-drainage - 10 - 40 years- Type 1 - initial flush of mine - - Type 1 - initial flush of mine -

first 10 years after mine closurefirst 10 years after mine closure- Type 2 - continued pyrite - Type 2 - continued pyrite

oxidationoxidation

• Below – drainage mines Below – drainage mines - 25 years between samples- 25 years between samples- pH from 3.0 to 6.1- pH from 3.0 to 6.1

• Above – drainage mines Above – drainage mines - 25 years between samples- 25 years between samples- pH from 3.0 to 3.5- pH from 3.0 to 3.5

Lambert and Dzombak, 2000

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

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

Historic samplingHistoric sampling1968 - EPA - 555 sites1968 - EPA - 555 sites1980 - WV DNR - 20 sites1980 - WV DNR - 20 sites2000 - WVU - 40 sites 2000 - WVU - 40 sites 2006 - WVU - 40 sites2006 - WVU - 40 sitesGraphs of acidity vs. time for 6 Graphs of acidity vs. time for 6

Pittsburgh and 34 Upper Freeport Pittsburgh and 34 Upper Freeport (UF) sites(UF) sites

Acidity collection

Compare to T&T #2Compare to T&T #2

- Closed in 1996- Closed in 1996

- Different decay rate?- Different decay rate?

Sites n 1968-1980 1980-2000 2000-2006 1968-2006

Pittsburgh 6 -83% -58% 87% -74%

0500

100015002000250030003500400045005000

1960 1970 1980 1990 2000 2010

Year

Aci

dity

(mg/

L as

CaC

O3)

Cheat 2

Cheat 5

Cheat PA 1

Lynn 1

Lynn 2

Lynn 3

Sites n 1968-1980 1980-2000 2000-2006 1968-2006

UF > 1600 12 -58% -44% 10% -81%

UF 600-1599 10 -43% -35% 5% -79%

UF 0-599 11 -23% -4% -42% -70%

Increasing UF 1 44% 47% -31% 46%

0500

10001500200025003000350040004500

1960 1970 1980 1990 2000 2010

Year

Aci

dity

(mg/

L as

CaC

O3)

Muddy 6

Muddy 9

Fickey 1

Bull 1

Martin 2

Muddy 11

Fickey 9

Bull 2

Glade 5

Glade 1

Fickey 7

Glade 4

0200400600800

100012001400160018002000

1960 1970 1980 1990 2000 2010

Year

Aci

dit

y (m

g/L

as

CaC

O3)

Fickey 8

Greens 3

Cheat 6

Muddy 10

Bull 5

Fickey 6

Greens 1

Middle 1

Glade 3

Bull 3

Sites n 1968-1980 1980-2000 2000-2006 1968-2006

UF > 1600 12 -58% -44% 10% -81%

UF 600-1599 10 -43% -35% 5% -79%UF 0-599 11 -23% -4% -42% -70%

Increasing UF 1 44% 47% -31% 46%

Sites n 1968-1980 1980-2000 2000-2006 1968-2006

UF > 1600 12 -58% -44% 10% -81%

UF 600-1599 10 -43% -35% 5% -79%

UF 0-599 11 -23% -4% -42% -70%Increasing UF 1 44% 47% -31% 46%

050

100150200250300350400450500550600650700

1960 1970 1980 1990 2000 2010

Year

Aci

dit

y (m

g/L

as

CaC

O3)

Muddy 2-1

Muddy 2-2

Muddy 2-3

Muddy 2-4

Muddy 7

Fickey 5

Martin 3

Glade 2

Muddy 3

Muddy 5

Greens 2

Sites n 1968-1980 1980-2000 2000-2006 1968-2006

UF > 1600 12 -58% -44% 10% -81%

UF 600-1599 10 -43% -35% 5% -79%

UF 0-599 11 -23% -4% -42% -70%

Increasing UF 1 44% 47% -31% 46%

050

100150200250300350400450500550

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

Aci

dit

y (m

g/L

as

CaC

O3)

Bull 4

Groups n 1968 1980 2000 2006

---------mg/L as CaCO3-------

Pittsburgh 6 2398 574 412 447

UF 34 1351 598 379 265

Group n 1968-1980 1980-2000 2000-2006 1968-2006

Pitts. 6 -6.3% -1.4% 1.4% -2.1%

UF 34 -4.6% -1.8% -5.0% -2.1%

% decrease of acidity per year

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

0 10 20 30 40 50 60 70 80 90 100 110

C/C

0 fo

r aci

dity

Time since closure (yrs)

0.02 rate of exp. decay

0.05 rate of exp. decay

0.10 rate of exp. decay

% of initial concentration

vs. time

(exponential decay)

Exponential decay:

C/C0=e-kt

C/C0=e-.02t

C/C0=e-.05t

C/C0=e-.10t

Pitts. exp. decay constant (k) = -0.044Pitts. exp. decay constant (k) = -0.044 Estimated initial acidity = 9,113 mg/L as Estimated initial acidity = 9,113 mg/L as

CaCOCaCO3 3 (3.86 relative acidity)(3.86 relative acidity)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 10 20 30 40 50 60 70 80 90 100 110

Time since closure (yrs)

C/C

68 f

or

acid

ity

-0.02 rate of exp. decay-0.044 rate of exp. decay-0.10 rate of exp. decayPitts2% dashed4.4% dashed10% dashed

2006 sampling

1968 Sampling

UF exp. decay constant (k) = -0.054UF exp. decay constant (k) = -0.054 Estimated initial acidity = 5,413 mg/L as Estimated initial acidity = 5,413 mg/L as

CaCOCaCO3 3 (4.01 relative acidity)(4.01 relative acidity)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0 10 20 30 40 50 60 70 80 90 100 110

Time since closure (yrs)

C/C

68 f

or

acid

ity

-0.02 rate of exp. decay-0.054 rate of exp. decay-0.10 rate of exp. decayUF2% dashed5.4% dashed10 dashed

Acidity at time of closure = 1,128 mg/L as Acidity at time of closure = 1,128 mg/L as CaCOCaCO33

T&T exp. decay constant (k) = -0.104T&T exp. decay constant (k) = -0.104 Increased decay rate due to first flush Increased decay rate due to first flush

0

0.2

0.4

0.6

0.8

1

1.2

0 10 20 30 40 50 60 70 80 90 100 110

Time since closure (years)

C/C

96 o

f ac

idit

y-0.02 rate of exp. decay

-0.05 rate of exp. decay

-0.10 rate of exp. decay

-0.104 rate of exp. decay

T&T acidity

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

Pitts. minesPitts. mines- Pitts. decay rate constant = -0.044- Pitts. decay rate constant = -0.044- Estimated initial acidity = 9,113 mg/L - Estimated initial acidity = 9,113 mg/L as CaCOas CaCO3 3 (3.86 relative acidity)(3.86 relative acidity)

UF minesUF mines- UF decay rate constant = -0.054- UF decay rate constant = -0.054- Estimated initial acidity = 5,211 mg/L - Estimated initial acidity = 5,211 mg/L as CaCOas CaCO3 3 (4.01 relative acidity)(4.01 relative acidity)

T&T #2T&T #2

- T&T decay rate constant = -0.104- T&T decay rate constant = -0.104

- Increased decay rate due to - Increased decay rate due to

first flushfirst flush

Questions?