United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/PS7-80-128 Oct. 1980
Project Summary
Water Infiltration Control to
Achieve Mine Water Pollution
Control—The Dents Run
Watershed Demonstration
Project
Jonathan G. Herrmann
One of the most severe mine drainge
problems encountered in the
Appalachian coal fields is the
discharge of highly acidic and iron-
bearing drainage from abandoned
underground mines. This problem is
aggravated by surface water
frequently draining into both active
and abandoned mines and exposed
auger holes. This water then reacts
with pyritic material in the roof and
floor of underground mines and forms
acid mine drainage, a diluted form of
sulfuric acid and ferrous sulfate. Since
many abandoned underground mines
were either sloped so that water
would gravity-drain from the mine
workings or have since intercepted
workings at higher elevations, the
contaminated mine water eventually
finds its way to a surface discharge
point.
In 1971, the Environmental
Protection Agency, Office of
Research and Development, awarded
a grant for a mine drainage
demonstration project on the Dents
Run Watershed. The grant was
awarded to the State of West Virginia,
Department of Natural Resources.
The state, in turn, contracted with the
Cyrus Wm. Rice Division of IMUS
Corporation in that year to conduct
the project feasibility study and
subsequent reclamation design and
monitoring program. Actual
reclamation of the Watershed
occurred in 1973 and the project was
completed following post-construc-
tion water quality monitoring in 1976.
The objective of the Dents Run
Watershed Demonstration Project
was to demonstrate the effectiveness
of surface mined land reclamation
measures in establishing surface
water infiltration control to prevent or
reduce pollution from acid mine
drainage. The Dents Run Watershed,
located in Monongalia County, West
Virginia, was replete with unreclaimed
surface mines, drift mines, auger
mines, refuse dumps, spoil banks, and
borehole discharges; all of which were
determined to be significant
generators of acid mine drainage.
The project was initiated with a
comprehensive field investigation of
the Watershed to locate and
characterize each mine site and
underground mine opening. Based on
this information and detailed analyses
of regional geologic conditions and
past mining history, areas of
suspected high infiltration were
identified. Site-specific reclamation
plans and specifications were then
prepared; these plans were designed
primarily to increase surface water
runoff and reduce infiltration of
surface drainage into underground
mine workings through unreclaimed
surface mines.
Over 40 hectares of surface mines
were reclaimed during this project and
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nearly 100 percent of the pollutional
drainage in the Dents Run Watershed
was eliminated through the
cooperative efforts of government
and industry. Virtually all of the mine
drainage from the active workings of
the cooperating industry. Consolida-
tion Coal Company, was treated to
acceptable water quality standards at
the Sears and Loar Treatment Plants
before discharge. The project report
defines the approach taken in the
reclamation effort, describes each
mine site and associated reclamation
activities, outlines monitoring
strategies, and analyzes the overall
effectiveness of the project.
This publication is a summary of the
complete project report, which can be
purchased from the National
Technical Information Service (see
box on last page).
Introduction
According to 1978 estimates, West
Virginia is the second largest coal
producing state, following Kentucky,
with atotal productionof 82 milliontons
of coal. Historically, West Virginia has
been one of the leading coal producing
states in the nation As a result of this
extensive mining activity, acid mine
drainage has been a significant problem
in the northern portion of the state
where the interaction of local geologic
and hydrologic conditions generally
produces severely polluted drainage
from both surface and underground
mining operations.
The Dents Run Watershed
Demonstration Project was designed to
address this problem The project was
conducted under the auspices of the
Environmental Protection Agency as
specified in the provisions of the Water
Quality Improvement Act of 1970, PL
91-224. The Act included a subsection
entitled "Area Acid and Other Mine
Water Pollution Control Demonstra-
tions." This subsection became Section
14 of the Federal Water Pollution
Control Act, as amended Section 14
provides for the demonstration of
techniques for mine drainage pollution
control and directs that the
Environmental Protection Agency shall
require such feasibility studies as
necessary in selecting watersheds for
the purpose of demonstration projects.
Such feasibility studies are to aid the
Environmental Protection Agency in
selecting not only the mine drainage
pollution control method(s), but also the
watershed or drainage area for such
application The Act requires that the
Environmental Protection Agency give
preference to areas which will have the
greatest public value and uses.
The Dents Run Watershed is located
in Monongalia County, West Virginia,
and is part of the Monongahela River
Basin. As a minimum, reclamation work
in the Watershed was to be performed
in accordance with applicable State and
Federal regulations In addition to this
general requirement, however, special
or innovative reclamation and
abatement techniques were to be
employed in areas of suspected high
infiltration in order to reduce drainage
into both abandoned and active
underground mine workings. It was
believed that this approach . could
reduce water infiltration by as much as
50 percent.
The terrain of the eastern part of the
Watershed can generally be described
as rugged and the western portion, as
rolling. The elevation of the highest
peak in the Watershed is approximately
488 meters, while the valley floor in the
vicinity of Laurel Point is 291 meters
high with a base of 253 meters at the
mouth of Dents Run. Located in the
Allegheny Mountains section, the
Watershed is part of the Appalachia
Plateau's physiographic province. The
mountain tops are forested, while the
valley sides and bottom are open
grassland and farmland Dents Run
flows from west to east and enters the
Monongahela River at the city of
Granville, which is due west of the city
of Morgantown
The most prominent and commercial-
ly developed coals in the Watershed are
the Pittsburgh, Redstone, Sewickley,
and Waynesburg seams. These coal
seams outcrop along the valley sides
beginning at the mouth of Dents Run
near Granville The lowest of these is
the Pittsburgh seam. The Redstone
seam is approximately 107 to 114
meters above the Pittsburgh seam The
Pittsburgh seam and all others above it
dip to the west. The elevation of the
Pittsburgh seam is 107 meters below
the valley floor at this point. A typical
cross-section of the Watershed is
depicted in Figure 1
Surface mining of the Pittsburgh,
Redstone, and Sewickley seams was
confined largely to the eastern end of
the Dents Run Watershed, and was
substantially completed prior to 1952.
Additional surface mining of these
seams took place between 1960 ar
1966. Surface mining of the Wayne
burg outcrop has been practiced ne
the hilltops throughout the Watersh(
since 1 966. The only drift mining not<
in the Waynesburg seam occurs c
isolated tracts in the extreme westei
portions of the Watershed, although tr
Pittsburgh, Redstone, and th
Sewickley seams have been drift mint
extensively in the eastern end of th
Watershed for many years.
Most of the unreclaimed surfat
disturbance occurs in the eastei
portion of the Watershed Water th,
entered the subsurface water system £
a result of numerous drift mine mte
ceptions located in the unreclaime
areas eventually drained into tr
Pittsburgh seam The original premis
of the project was that surface reclam;
tion techniques could be employed i
backfill the surface mine pits, cover th
exposed seam, and seal the expose
drift mine entries or interceptions i
order to reduce the surface water enti
into the subsurface water system. Th
intercepted runoff would then b
channeled to the normal surfac
drainage courses in the Watershed
Technical Approach
At the onset of this project, th
Consolidation Coal Company operate
six boreholes which discharged water t
the Dents Run Watershed (see Figur
2) Five of the six boreholes discharge
water Irom active or inactive under
ground mine workings within th
Pittsburgh coal seam. These pump
were located within the mines, two c
these, the Valotto and the Laurel Poim
were constant discharge pumps Th
Hess, Six-Right, and Loar pumps wer
float-controlled. Surface wate
intercepted by abandoned unreclaime
mining operations in the eastern portio
of the Watershed drained to the Hes
discharge point and then continued 01
to Laurel Point The Laurel Pom
pumping facilities handled a smal
port ion of this drainage while the exces;
continued on to either the Loar or Six
Right discharge points. The Snide
borehole discharged water from thi
Sewickley coal seam and the pump wa:
float-controlled.
As previously stated, the objective o
this comprehensive mine drainag*
abatement program was to demonstraK
the effective reduction of pollution frort
acid mine drainage through surfact
water infiltration control This was to b|
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Tributary to
Dents Run
, Snider Borehole
Discharge
Waynesburg Coal
Dents Run Near
Monitor Station
Note
- Vertical Exaggeration = 15
-Coal Dips 2% to the West
Tributary to Dents Run Near
Mess Borehold Discharge
Tributary to Dents Run Near
Sewickley /Monitor Station No 2
Coal
Redstone Coal
Pittsburgh Coal
Section I
Dents Run near,
Monitor Station
Number 1
Monongahela
_ River I
Figure 1. Typical cross section Dents Run Watershed
2000 0 2000 4000 6000
Scale in Feet
'igure 2. Borehole locations.
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accomplished by selectively employing
specialized reclamation techniques at
those abandoned surface mines
identified as contributing significantly
to infiltration
The first and most important step in
such an effort was determining where
interconnections existed between
underground workings and the surface.
This investigative analysis was initiated
early in the study and continued
throughout the fall and winter of 1 971.
Each surfce mine area, underground
mine opening, and refuse bank was
located and evaluated as to its pollution
potential or its potential to contribute to
the underground mine water volume. A
priority listing was then developed for
the work to be performed Priority I sites
referred to those areas which
contributed significant amounts of
drainage to the underground mine
workings, while Priority II sites were
those which contributed directly to
stream pollution as a result of surface
water runoff Priority III sites were those
areas which contributed to aesthetic
pollution; this includes all of the areas
within the Watershed which were not
included in the first or second priority
listing.
Reclamation work performed as a
result of this study was primarily of the
contour and pasture-type backfills
(Figures 3A and 3B) depending upon the
condition of the highwall at each site
The pasture-type backfill was used in
areas where the highwall was relatively
sound and the contour backfill was used
where the highwall was highly
fractured In each case, the backfills
were compacted in order to prevent
excessive infiltration into the inter-
cepted deep mine workings and auger
holes.
Several of the surface mines
contained water impoundments in
portions of the unreclaimed pit. When
the reclamation work required draining
these impoundments, portable
treatment facilities were employed to
provide adequate treatment of the
impounded water prior to discharge to a
receiving stream.
Conventional heavy construction
equipment was used.in the regrading of
the surface mines; conventional farm
equipment was used in the surface
preparation; and seeding, mulch, and
fertilizer were applied by hydroseeder
Compaction of the backfill in the area of
auger mined highwalls was done using
a conventional 55-ton roller used in
highway construction AmmimumoflO
4
passes were made with the roller. The
reclamation specifications calledforthe
placement of impervious material in
maximum 61 -m3 lifts in the area from
the base of the highwall, a minimum of
6 meters vertically, and at leasts meters
above any auger holes or mine
openings. Where impervious material
was not available, the contractor used
the best material available.
An important part of a demonstration
project of this nature is documentation
of the effectiveness of the control
measures being employed In this
project, the quality and quantity of
natural stream flows and borehole
discharges in the Watershed were
monitored. It was felt that this approach
would show both the reduction of acid
mine drainage as evidenced by Consoli-
dation Coal's reduced pumping rates,
and the increase in stream quality due
to the increase in natural surface water
runoff
To this end, a network of seven
stream-monitoring stations was
installed to record transient qualitative
and quantitative effects. These monitor-
ing stations were designed to continu-
ously record pH, conductivity, andflow
Initially, grab samples were collected on
a weekly basis at each monitoring
station. These samples were analyzed
for pH, total iron, sulfate, turbidity, total
Original Ground Slope
acidity, alkalinity, and conductivit
Samples were also collected at month
intervals at both the stream momtorin
stations and borehole discharge
These samples were analyzed fc
alkalinity, total acidity, conductivity, pi-
turbidity, calcium, magnesium, sulfati
total iron, ferrous iron, total solid;
suspended solids, dissolved solid;
settleable solids, aluminum, an
manganese. Due to the relativ
inaccessibility and sporadic operation <
the borehole discharge pumps, accural
pumping data was only available for th
Snider and Six-Right borehol
discharges
In conjunction with the aforemer
tioned comprehensive reclamatio
effort, Consolidation Coal Compar
constructed two mine dramge trea
ment plants to treat discharges from th
boreholes These facilities are describe
below
The Loar Treatment Plant
The Loar discharge and the Laur
Point discharge were combined unde
ground and an acid mine drainac
treatment plant was constructed at th
Loar site. This plant consisted of
conventional hydrated lime neutralizj
tion—aeration system and impoum
ment for settling and sludge storag
Backfilled Ground Slope
Figure 3A. Typical contour backfill
.Or/
Figure 3B. Typical pasture backfill
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The plant was designed for a flow of 637
liters/second, contains a dam 24 m
high and 259 m long, and impounds an
area of approximately 5 3 ha with a
capacity of 25 x 108 liters It was
designed for a 25-year life. This plant,
activated in October 1 973, hasoperated
satisfactorily since startup with no
major problems Recent water quality
data reported as part of federal water
quality monitoring program has shown
compliance with all applicable water
quality standards Table 1 showstypical
water quality data before and after
treatment, as analyzed and reported by
Consolidation Coal Company
Table 1. Water Quality at Loar
Treatment Plant.
Before Component After
27
3170 mg/l
860 mg/l
0
pH
Acidity
Iron
Alkalinity
8.2
0
< 2 mg/l
> Acidity
The Sears Treatment Plant
The Hess, Six-Right and Valotto
discharges were pumped underground
to the Sewickley seam where they were
combined with the water discharging
from the Snider borehole and treated
near the Snider site The Sears facility
consisted of a conventional hydrated
lime neutralization—aeration system
and an impoundment for settling and
sludge storage The plant was designed
for a flow of 252 liters/second, contains
an earthen dam 34 m high and 329 m
long, and impounds an area of
approximately 15 ha with a capacity of
1 89 x 109 liters It was designed with a
25-year life. This plant was activated in
September 1974. The discharge from
this plant is also reported to be m
compliance with all applicable water
quality standards Table 2 showstypical
water quality data before and after
treatment as analyzed and reported by
Consolidation Coal Company
Table 2. Water Quality at Sears
Treatment Plant.
Before Component After
3.3
250 mg/l
217 mg/l
0
pH
Acidity
Iron
Alkalinity
7.3
0
< 2 mg/l
> Acidity
Conclusions
As a result of this cooperative effort of
government and industry (Consolida-
tion Coal Company), nearly all of the
mine drainage pollution which was
discharging to the Dents Run
Watershed at the outset of the project
was controlled. As evidenced in Tables
1 and 2, a 99-percent reduction in the
level of acidity and iron concentrations
contributed to Dents Run was realized
This was accomplished through the
previously described reclamation
activities as well as the design and
construction of two mine drainage
treatment facilities by Consolidation
Coal Company
Surface reclamation techniques
employed during the project appeared to
have reduced the volume of drainage,
although flow monitoring data was not
sufficiently detailed to substantiate this
suspicion Weirs constructed to accom-
modate continuous stream flow
measurements were extremely costly
and a constant source of problems due
tosiltation andfloodmg Parshallflumes
are much more suitable to this type of
application because sediment is less
likely to be trapped in the control section
of the flume and cause flooding and
inaccurate stream flow measurements
Since stream flow measurements
through the wetrs could not be
accurately made, the pumping
rates from the Snider and Loar bore-
holes were used in assessing the
effectiveness of the project in reducing
surface water infiltration At the onset
of the study, the Hess, Loar, Six-Right,
and Laurel Point boreholes discharged
water from the Pittsburgh coal seam
and the Snider borehole discharged
water from the Sewickley seam This
system was later changed so that Hess,
Six-Right, and Valotto, discharges were
pumped underground into the
Sewickley seam, which was then
dewatered through the Snider borehole
The Loar and Laurel Point waters were
combined and discharged through the
Loar borehole The overall Watershed
pumping rates would reflect the total
volume of water infiltrating the Dents
Run Watershed provided that no water
was transferred from this area to
another drainage basin. Assuming this
to be correct, the decrease in the volume
of water discharged from the Sewickley
seam in 1972 and 1974 was
Borehole 1972 1974
Snider 4.54x106 m3 3.31x106 m3
The years 1972 and 1974 were
chosen for study since the rainfall for
those two years is approximately the
same (see Figure 4) and reclamation of
the Watershed occurred between those
two years This resulted m a discharge
reduction of 4 54x1 O6 m3 - 3 31x106 m3
= 1 23x106 m3
The percent reduction for this period
was 1 23x106 m3 - 4 54x106 m3 x 1 00 =
27 percent
When the pumping rates recorded at
Loar borehole were considered, the
following discharges were calculated
Borehole 1972
1974
Snider 4 54 x 106 m3 3 31 x 106 m3
Borehole 1972 1974
Snider 4 54 x 106 m3 3 31 x 1 O6 m3
Loar 38 x 106 m3 12 x 106 m3
TOTAL 4 92 x 106 m3 3 43 x 1 O6 m3
This resulted m a discharge of 4 92 x
1 O6 m3 - 3 43 x 106 mj = 1 49 x 106 m3
The percent reduction for this period
was 1 49 x 106 m3 - 4 92 x 1 O6 m3 x 1 00
= 30 percent
Although this percentage figure is
short of the potential 50 percent
reduction believed possible at the onset
a
Key:
60
50
40
"6 n
14
"12
-w
~ —
30\8
Tfi
20\-
10
l_
"2
<^
$
y
|
I
$
—
•7^
x
v
l~1 Pumpage
M Precipi-
L-^ tation
<0
OJ
•+J
2^
IbU
100
^50
1971 1972 1973 1974
Figure 4.
5
Borehole pumpage vs
precipitation
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of this project, it nevertheless repre-
sents a very significant total volume of
water - 4,100 mVday - from the
combined discharges of the Snider and
Loar boreholes.
Over 40 hectares of orphaned surface
mined land were regraded and revege-
tated during this project. Unfortunately,
inadequate post-reclamation mainten-
ance has resulted in sparse vegetative
cover and development of erosion
gullies.
Recommendations
Reclamation projects of this nature
should incorporate a routine
maintenance program to assure the
continued success of vegetative cover
and minimize degradation of the site by
erosion and/or sedimentation Also,
access to reclamation sites should be
controlled to prevent degradation of the
site by dumping of trash and debris,
grazing of livestock, and/or disruption
of water drainage systems by rutting
from vehicular traffic
State and Federal reclamation
agencies should develop inventories of
the mine sites where selective
reclamation techniques (such as those
demonstrated in this study) can be
employed to reduce infiltration into
underground mine workings. By so
doing, the responsible government
regulatory agency could work with
cooperating mine operators to modify
reclamation practices in order to obtain
maximum benefit on ongoing
reclamation efforts
This Project Summary was authored by Jonathan G. Herrmann, who was also
the EPA Project Officer (see below)
The complete report, entitled "Water Infiltration Control to Achieve Mine Water
Pollution Control—The Dents Run Watershed Demonstration Project" was
authoredbyJ. D. Robinsof Robins andAssociates for Hittman Associates, Inc.,
Lexington, KY 40511
The complete report (Order No. PB 80 217748, Cost: $ 12.00, subject to. change)
will be available from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone- 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
> US GOVERNMENT PRINTING OFFICE 1981 -757-064/02E9
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