Program
All Presentations (pdf)
Monday
8:15 Brent Means
10:10 James J. Gusek
12:40 Jonathan M. Dietz
2:15 Kimberly R. Weaver
4:00 Brent Means
Tuesday
8:45 Robert Kleinmann
9:15 Brent Means
9:30 James J. Gusek
10:00 Glenn C. Miller
10:30 Linda Ann Figueroa
12:40 Art Rose
1:10 Charles A. Cravotta III
1:40 Danielle M C Huminicki
2:50 Bernard Aube
3:20 Timothy K. Tsukamoto
3:50 Bradley R. Shultz
4:20 Kimberly R. Weaver
Wednesday
8:00 Linda Ann Figueroa
8:30 John Senko
9:00 Song Jin
10:10 Jonathan M. Dietz
10:40 Daryle H. Fish
12:40 John Chermak
1:10 Griff Wyatt
1:40 Dan Mueller
2:50 Sean C. Muller
3:20 Jack Adams
3:50 Roger Bason
3:50 Mark B. Carew
Thursday
8:00 Rep. John E. Peterson
8:30 Scott Sibley
9:00 Charles A. Cravotta III
9:30 Michael R. Silsbee
10:30 Lykourgos
Iordanidis
11:00 Mark Conedera
11:30 Barry Scheetz
1:25 William Benusa
1:55 Mike Sawayda
2:25 Susan J. Tewalt
3:25 Robert S. Hedin
3:55 Chad J. Penn
4:25 Ron Neufeld
Thursday 9:00 Charles A. Cravotta III, Ph.D., P.G., Hydrologist/Geochemist, USGS
Relations among pH, sulfate, and metals concentrations in Anthracite and Bituminous coal-mine discharges, Pennsylvania
Author(s)
Charles
A. Cravotta III, Ph.D., P.G., Hydrologist/Geochemist
U.S. Geological Survey, Water Resources Division
215 Limekiln Road
New Cumberland, PA 17070
717-730-6963
cravotta@usgs.gov
Abstract
Water-quality data for discharges from 140 abandoned underground mines
in the bituminous and anthracite coalfields of Pennsylvania illustrate
relations among pH, sulfate, and dissolved metal concentrations. The
pH for the 140 samples ranged from 2.7 to 7.3; with two modes at pH 2.5
to 4 (acidic) and pH 6 to 7 (near neutral). Although the pH distribution
was similar for the bituminous and anthracite discharges, the bituminous
discharges had smaller median flow rates and greater concentrations of
sulfate, iron, aluminum, and various other metals than anthracite discharges
with the same pH values. The observed relations between the pH and metals
concentrations can be attributed to (1) dilution of acidic water by alkaline
ground water; (2) solubility control of aluminum, iron, manganese, barium,
and lead by hydroxide, sulfate, and/or carbonate minerals; (3) adsorption
control of arsenic and selenium; and (4) formation of aqueous complexes
between dissolved metals and sulfate ions. The formation of aluminum-sulfate
complexes can account for 10 to 100 times greater concentrations of dissolved
aluminum in bituminous discharges compared to anthracite discharges at
similar pH. The complexes add to the total dissolved aluminum concentration
at pH of equilibrium with aluminum hydroxide or hydroxysulfate minerals.
In contrast, bituminous discharges have lower lead and barium concentrations
than anthracite discharges indicating elevated sulfate concentration
decreases solubility of these metals. These general relations and processes
as described for underground abandoned mine discharges are applicable
to the understanding of drainage from surface coal mines and metal mines
and of reactions during acidity titrations and treatment of mine drainage.
Table 1: Composition of discharges from abandoned coal mines in Pennsylvania,
1999
[median(minimum;maximum)]
Coalfield & number of samples |
Flow Rate |
pH |
Oxygen |
Sulfate |
Iron |
Manganese |
Alumnum |
(m3/min) |
(mg/L) |
||||||
Anthracite |
N=41 |
3.84 |
5.1 |
1.9 |
260 |
15 |
2.9 |
0.28 |
(0.01;132) |
(3.0;6.3) |
(0.3;11.1) |
(34;1300) |
(0.046;312) |
(0.019;19) |
(0.007;
26) |
|
Bituminous N =99 |
0.75 |
5.2 |
0.6 |
580 |
43 |
2.3 |
1.5 |
(0.01; 16.7) |
(2.7;7.3) |
(0.2;11.5) |
(120;2000) |
(0.16;512) |
(0.12;74) |
(0.008;
108) |
|
Coalfield & number
of samples |
Arsenic |
Selenium |
Yttrium |
Barium |
Lead |
Nickel |
Zinc |
(mg/L) |
|||||||
Anthracite N=41 |
0.62 |
0.4 |
2.9 |
18 |
0.68 |
83 |
130 |
(<0.03;15) |
(<0.2;3.9) |
(0.18;44) |
(13;31) |
(<0.1;11) |
-19,620 |
(3.0;1000) |
|
Bituminous N =99 |
2 |
0.6 |
15 |
13 |
0.1 |
90 |
140 |
(0.1; 64) |
(<0.2;7.6) |
(0.11;530) |
(2.0;39) |
(<0.1;4.6) |
(2.6;3200) |
(0.6;10,000) |
|
Biography
Dr. "Chuck" Cravotta is a research hydrologist at the U.S.
Geological Survey Pennsylvania Water Sciences Center and adjunct Assistant
Professor of Environmental Engineering at Penn State Harrisburg. He received
his B.A. in Environmental Sciences from the University of Virginia and
his M.S. and Ph.D. in Geochemistry and Mineralogy from the Pennsylvania
State University. His research emphasizes field and laboratory applications
of geochemical and hydrological methods for the characterization and
treatment of drainage from coal mines.