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o
/A newsletter about soil, sediment, and ground-water characterization and remediation technologies
Issue 37
This issue o/Technology News and Trends highlights innovative approaches to remediate
and reclaim former mining sites and larger areas impacted by abandoned mining sites.
Environmental problems associated with mine-scarred lands include revegetation difficul-
ties, waste piles or dumps contributing to metal-loading in surface water, and acid mine
drainage (AMD) deteriorating regional surface and ground water quality.
Passive Systems Treat AMD While Allowing Recovery of Metal Oxides
A public-private partnership is installing a
series of passive treatment systems to treat
AMD from abandoned surface and
underground coal mines in western
Pennsylvania. Since 1994, the Slippery
Rock Watershed Coalition has constructed
16 systems annually treating over 750
million gallons of AMD. Each system
typically employs a sequence of natural
gradient-driven treatment steps involving
settling ponds, vertical-flow ponds
containing limestone and organic material
such as compost, and constructed
wetlands to treat surface water that is
diverted from (and later returned to)
mining-impacted streams. Under the state's
Growing Greener Program, academic
volunteers and the Pennsylvania
Department of Environmental Protection
(PA DEP) have noted significant
improvements in water quality of receiving
streams as well as a return offish in about
11 miles of headwaters streams as a result
of AMD treatment. Sale of metal oxides
reclaimed from the treatment systems helps
cover maintenance costs for existing
systems and is anticipated to help install
new systems addressing other abandoned
discharges in the region.
PADEP investigations in 1998 indicated that
mine drainage into Seaton Creek, a major
headwaters tributary, contributed 42% of
the acid load and 49% and 41% of the iron
and aluminum loadings, respectively, to
Slippery Rock Creek. The findings focused
cleanup efforts on Seaton Creek at a 40-
year-old, 100-acre surface mine known as
the De Sale Restoration Area. The target
area for metal oxides recovery at this mine
comprises an unnamed tributary with pH
averaging 3.1 and acidity (the amount of
base needed to neutralize a volume of water)
of 100-450 mg/L. Metal concentrations in
surface water range from 10 to 80 mg/L
total iron, 20-80 mg/L total manganese, and
5-15 mg/L total aluminum. Stream flow
ranges seasonally from 10 to 500 gpm.
Remedy construction included installation
of a 16-ft-wide by 3-ft-high instream dam
with 6-in and 8-in intake pipes allowing
diversion of up to 700 gpm under the natural
gradient into the treatment system. The
entire stream (except during occasional
storm events) is diverted into an 8,000-ft2
forebay to settle solids and debris. Upon
exiting the forebay, water passively flows
to two flushable vertical-flow ponds
operating in parallel to neutralize acidity,
raise pH, and remove metals. Each 20,000-
ft2 pond contains 2,200 tons of limestone
aggregate overlain by a 0.5 -ft layer of spent
mushroom compost. Iron oxides precipitate
at low pH above the compost as water
percolates down through the component.
Two tiers of perforated plastic pipe within
the aggregate of each vertical-flow pond
collect and transfer water to a 0.2-acre, 5-
ft-deep settling pond. A riprap-lined spillway
allows water to then pass to a 1.5-acre, free-
[continued on page 2]
July 2008
Contents
Passive Systems
TreatAMD While
Allowing Recovery of
Metal Oxides
pagel
Ecological Approach
Used to Remediate
Former Mining Site page 3
Interagency Study
Examines Impacts
of Mine Spoil Types
on Reforestation
Efforts
Upcoming
Conferences
page 4
page6
CLU-IN Resources
CLU-IN provides an online
"issue area" to help stake-
holders clean up and reclaim
Mining Sites (http://
cluin.org/issues/). Resources
include a link to EPA's
Abandoned Mine Land
webpage, which contains
site-specific case studies,
technical information on
geochemistry, characteriza-
tion, and remediation, and
research reports on unique
aspects such as metals
loading and attenuation.
Recycled/Recycl abl e
Printed with Soy/Canola Ink on paper thai
contains at least 50% recycled fiber
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[continued from page 1]
flowing, aerobic, constructed wetland to
precipitate amorphous iron hydroxides at
circumneutral pH (Figure 1). Upon
exiting the wetlands, water enters a
horizontal-flow limestone bed containing
2,900 tons of limestone aggregate that
removes manganese and provides an
alkalinity boost for additional buffering
capacity do wnstreamTreated water finally
discharges througha 10-inpipe into arock-
lined channel that returns flow to the
watercourse at a location approximately
1,000 feet below the intake.
The treatment system was constructed
over six weeks in June-July 2000.
Limestone (90% CaCO3) aggregate was
obtained from a local quarry three miles
distant at a material and delivery cost of
$12/ton. Spent mushroom compost was
obtained from an agricultural producer
based 12 miles away, at a material and
delivery cost of $10/yd3.
The system currently neutralizes
approximately 180 pounds of acid
discharge each day. Daily reduction rates
for metals average 20 pounds of iron, 8
pounds of aluminum, and 25 pounds of
manganese. Monitoring of surface water
re-entering the stream after treatment
typically shows a pH of 6-7 with total iron
and aluminum concentrations less than 2
mg/L and manganese concentrations at
least 50% lower than intake levels.
Sampling of treated surface water in
Spring 2008 indicated pH 6.7, alkalinity
60 mg/L, acidity -33 mg/L, dissolved iron
0.1 mg/L, dissolved aluminum 0.1 mg/L,
and dissolved manganese 14 mg/L. These
results represent 100% neutralization of the
acid discharge and 99%, 99%, and 70%
reductions of iron, aluminum, and
manganese concentrations, respectively.
Efforts to recover manganese oxide from
the horizontal-flow limestone bed began last
fall. Recovery equipment for dewatering,
separation, and handling of manganese-
bearing material included a 21-metric-ton
excavator equipped with a "flip screen"
attachment to screen materials, a gasoline-
powered water pump, and 1-yd3 bulk
storage containers. About 30 tons of
recovered material currently is stockpiled
offsite, and an estimated 20 tons of material
remain for future recovery. Additional
drying and screening can be conducted
before reuse, depending on user needs.
Preliminary laboratory results indicate the
unprocessed, recovered material consists
of approximately 25% manganese oxide
with the remainder constituting primarily
quartz, limestone, and water.
A large-scale effort to recover the iron oxide
precipitating at low pH is planned for later
this summer. Recovery will employ a small
excavator to remove an estimated 200 yd3
of material collected in the existing vertical-
flow ponds. In order to provide continuous
treatment, the process directs all raw water
to one pond while recovering iron oxide
precipitate from the other and vice versa.
Recovered iron oxide will be used as
pigments for bricks, concrete, and
ceramics. Commercially available material
of similar quality currently is sold in the
area for about $0.50 to $1 per pound.
The non-profit Stream Restoration, Inc.
assists the Slippery Rock Watershed
Coalition in coordinating treatment
system installation and maintenance. The
partnership relies on field assistance from
Grove City College, Westminster
College, and Slippery Rock University
students, mining companies, local
residents, and other youth or service
organizations. Recovered manganese
and iron oxides have been used by local
artists as colorants in ceramic glazes,
and future markets are anticipated to
include manufacture of "green"
products such as tile and paint.
Since 2005, the PA DEP has awarded
over $4 million in innovative technology
grants to develop cost-effective
industrial applications helping to treat the
state's estimated 23 billion gallons of
AMD from active and abandoned coal
mines. Other innovative strategies
explored under the Growing Greener
initiative include self-flushing limestone
systems, steel slag as treatment media,
and optimization and combination of
passive treatment systems providing
added value to site cleanup.
Contributed by Scott Roberts,
Deputy Secretary of the Office of
Mineral Resources, PA DEP
(jayroberts&state.pa.us or 717-783-
5338), Margaret Dunn, Slippery Rock
Watershed Coalition, and Cliff
Denholm, Stream Restoration, Inc.
(sri&streamrestorationinc. org or
724-776-0161)
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Ecological Approach Used to Remediate Former Mining Site
Cleanup of the inactive Burlington
Mine site in Boulder County, CO, was
initiated in 2003 as a voluntary cleanup
overseen by the Colorado Department
of Public Health and Environment
(CDPHE) pursuant to the Colorado
Voluntary Cleanup Redevelopment Act
of 1994. An ecological approach was
used to improve downstream water
quality, reduce surface- and ground-
water interaction with contaminated
materials, and limit potential for
subsidence. Activities included the
filling and mounding of subsidence pits,
realignment of intermittent tributaries,
management of surface-water runoff,
and revegetation of barren areas.
The 11-acre property was used by
several companies from 1920 to 1973
to produce fluorspar (calcium fluoride),
an active ingredient of fluorinated
compounds commonly needed for
water fluoridation and ceramic
manufacturing. In the 30 years prior
to cleanup, the site experienced
significant and increasing subsidence.
Site investigations in 1999 indicated
acidic and metals contamination in
waste rock onsite and in the adjacent
surface-water drainage. Geotechnical
investigations indicated a 12- to 15-
foot layer of alluvium overlying
bedrock at a depth of 25 feet below
ground surface. Ground water is
encountered at a depth of 8-10 feet.
Field preparation began with
consolidation of 25,000 yd3 of acid-
generating waste rock and closure of
three onsite adits and shafts. Activities
then focused on addressing three
subsidence pits that provided direct
paths for flow of contaminated material
from the subsurface mine workings to
surface and ground water. Of particular
concern was a 1/3-acre pit that
intercepted intermittent drainage from
Balarat Gulch in the Lefthand Canyon
watershed. Approximately 17,000 yd3
of uncontaminated or neutralized onsite
soil was used to backfill the pits.
Sufficient material was added to create a
minimum 2% slope for discouraging
infiltration and promoting runoff. In
anticipation of the backfill settling, the
area was over-mounded 4 feet.
Significant water interactions associated
with Balarat Gulch were addressed by
constructing a 500-ft diversion channel
to realign drainage away from mine
workings. The design used a step-pool
configuration typical of high-gradient
alpine streams, whereby system stability
relies on closely spaced, low-profile
drop structures (i.e., elevation
reductions) to dissipate flow energy.
Construction of the channel bed in this
way helped to more closely imitate
natural channel form and function,
incorporate naturalizing elements, and
create aquatic and riparian habitat.
Three-dimensional mining maps were
used to identify the channel's optimal
centerline location and inversions. The
channel design accommodated sizing
and configuration sufficient to contain
the design discharge of 264 cfs, which
is 120% of a 100-year storm event. In
an upper reach of the diversion channel,
where realignment required a sharp bend
away from the historic surface-water
path, a PVC liner was installed to fully
confine water and reduce potential for
piping failure behind a constructed 10-
ft-wide, 2-ft-high boulder wall. Two
lower reaches of the channel were left
unlined to allow hillslope ground water
to access the new channel rather than
flowing beneath it and potentially
accessing the mine workings below.
The Balarat Gulch diversion channel
required excavation at a steep (2:1-2.5:1
horizontal :vertical) 1/2-acre sideslope. To
prevent erosion, the slope was stabilized
with a native seed mix including mountain
mahogany (Cercocarpus montanus) and
bitterbrush (Purshia tridentata) shrubs
suited for optimal establishment on
bedrock face microniches. Following
seeding, the slope surface was amended
with Biosol® prior to installing a
biodegradable woven-coconut coir
erosion control fabric.
A primary alluvial water control
structure extending to bedrock was
installed at the top of the diversion
channel to address subsurface flow.
The engineered structure comprises a
75-ft-long, 25-ft-deep impermeable
liner and curtain drain consisting of
prefabricated drainage panels with
perforated PVC pipe threaded through
bottom sleeves. The impermeable
lining intercepts alluvial water and
forces it into the curtain drain
system. Localized ground water and
surface water not intercepted by the
primary control system are captured
in a secondary, downstream
"scavenger" drain.
Revegetation focused on stabilizing the
site, promoting evapotranspiration,
and preventing precipitation and
subsurface infiltration. Preparations
required surface application of
agricultural lime to neutralize acid
generation potential of the waste rock.
Approximately 15 tons of lime were
applied per 1,000 tons of waste rock
throughout the backfilled areas. These
areas were covered with 12-18 inches
of native subsoil and topdressed with
"type A" commercial compost at a rate
of 60 tons per acre. This created a
physical barrier to precipitation reaching
the waste rock and provided a suitable
medium for plant growth. A seed mix
of native grasses, wildflowers, and
shrubs was broadcast seeded at a rate
of 240 pure live seed (PLS) per square
foot. Shrub and tree plantings included
over 220 riparian species such as thinleaf
[continued on page 4]
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[continued from page 3]
alder (Alnus incana), 150 upland shrub
species such as wax currant (Ribes
cereum), and 20 ponderosa pine trees
(Pinus ponderosa).
A mobile bed of soil and rock gradations
in the natural channel was used to allow
mobilization by low-intensity storms, as
in a natural, dynamic system. Material
mobility results in natural scour and
deposition cycles capable of forming
localized pools or overly wide water
flow. The mobile bed is underlain by a
resistive, grouted riprap layer providing
vertical protection against channel
lowering. To replicate native
conditions, natural rock and boulders
were given preference over concrete
during construction of the bed and bank
treatments. Creating small notches in
the tops of the drop structures in an
alternating alignment encouraged
development of low-flow channels with
increased sinuosity.
After 12 months of remedy operation,
corrective measures were required to
address unanticipated drainage along
the hillslope of Balarat Gulch. Deep rills
had developed under the erosion control
fabric due to interception of several
small drainages and a ground-water
seep caused by remedial excavation; in
some areas, the fabric was stretched
to failure by underlying erosion. Woody
material was installed where possible to
reroute flows and serve as supplemental
breaks to drainage flows, and a
subsurface drain system was installed
to collect and route seep water around
the vulnerable hillslope to more stable,
vegetated areas. Large rills were
regraded to the extent possible and
erosion control fabric was re-installed
in problem areas.
Wildlife protection methods included
installation of Bird Balls™ recommended
by the U.S. Fish and Wildlife Service to
prevent waterfowl from landing or
residing in a pond receiving constant
discharge from underlying mine tunnel.
After three growing seasons, vegetative
coverage is as low as 5% (in sections
of the steep 2:1 hillslope), but as high as
85% in other areas (Figure 2). Complete
revegetation is expected to require 10-
20 years. CDPHE estimates a total
cleanup project cost of $1.5 million, or
about $140,000 per acre.
Contributed by Angus Campbell,
CDPHE (angus. campbell&state. co.us
or 303-692-2000) and James Cow art
and Julie Ash, Walsh Environmental
Scientists and Engineers, LLC
(jcowart(q)M>alshenv. com,
jeash&walshenv.com or 303-443-
3282)
Interagency Study Examines Impacts of Mine Spoil Types on Reforestation Efforts
The University of Kentucky, in
cooperation with the U.S. Department
of Interior (DOI) Office of Surface
Mining, the Kentucky Department of
Natural Resources, and the coal
industry has initiated a research
program to examine reforestation
techniques on surface mined lands.
Research plots were established on the
Bent Mountain surface mine in Pike
County, KY, forthe purpose of evaluating
the influence of three different loose-
graded spoil types on tree performance,
water quality, and hydrology.
Historically, reforestation was used to
reclaim sites impacted by surface
mining in the Eastern U.S. The passage
of the Surface Mining Control and
Reclamation Act of 1977 required that
mined lands be returned to their
approximate original contour (AOC).
Spoil compaction involved in
reconstructing sites to the AOC often
hinders reforestation efforts,
contributing to a decline in the
amount, diversity, and productivity of
forestland in coal-producing areas.
Compacted soil and inappropriate
geochemical characteristics often lead
to high seedling mortality, slow plant
[continued on page 5]
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[continued from page 4]
growth, accelerated erosion, and
deteriorated quality of receiving
streams.
Previous research on mined lands has
shown that loosely graded topsoil,
weathered sandstone, and other non-
toxic topsoil substitutes are suitable
growing media for establishing native
hardwood forests in Appalachia (Figure
3). Research is now helping to evaluate
media other than topsoil and the
influence of loose-grading techniques.
The Bent Mountain surface mine covers
a total of more than 1,000 acres,
including 150 acres of reforestation
research areas. University of Kentucky
researchers constructed one-acre test
plots to evaluate three on-site spoil types:
(1) predominately brown weathered
sandstone (brown); (2) predominately
gray un-weathered sandstone (gray); and
(3) mixed weathered and un-weathered
sandstones and shale material (mixed).
Prior to placement of the spoil in each
plot, a system of drain pipes and tipping
buckets was installed on a stable mine
surface to capture and measure
infiltrated water that percolated through
the spoil. Six to eight feet of the
respective spoil material was end
dumped from a truck on top of the
drainage system in each plot. Four tree
species (white oak, yellow poplar, red
oak and green ash) were planted into
the loose spoils at a rate of 800 per acre.
Physical and chemical characteristics
of the spoils indicated that the brown
Figure 3. University of Kentucky
studies at the Starfire surface mine of
eastern Kentucky in 1996 showed that
yellow poplar (Liriodendron tulipifera)
showed increased survivability when
soil compaction was minimized through
one or two bulldozer "strike-off"
passes and reduced machinery traffic.
spoil type exhibited a higher productivity
potential than the gray and mixed spoil
types due to a finer soil texture, higher
cation exchange capacity, higher
phosphorous concentration, and a pH
more suitable for native hardwood trees.
After three years, the gray spoil type had
an overall higher mean tree seedling
survival (88%) than the brown spoil
(86%) and mixed spoil (81%), but no
significant differences in survival were
observed among spoil types. The brown
sandstone plots however, showed
significantly more growth in height and
diameter than the gray and mixed plots.
Mean tree volume index was 230, 80,
and 40 cm3 for the brown, mixed and
gray, respectively.
Results showed that loose-graded
spoil exhibited low discharge volumes
to surface water, small peak
discharges, and long durations of
discharge. Storm flow characteristics
and mean runoff curve numbers were
similar to that of an unmined reference
forested watershed. Surface water
interception and storage is expected
to increase as the forest matures,
thereby further reducing discharge
volumes and peak discharges.
Electrical conductivity (EC), as an
indicator of water quality and ionic
strength, decreased by 75% in the
gray and mixed spoil types, while
concentrations in the brown
remained steady. After three years,
EC levels for all spoil types were
below 500 uS/cm-a reported
threshold level for mayflies
(Ephemeroptera), a pollution indicator
species for headwater streams of the
Central Appalachian Mountains.
Study results indicated that topsoil
substitutes can be used effectively as
growth media for native vegetation
when combined with field techniques
for loose grading and minimized
surface compaction. Strategies relying
on these techniques are being
incorporated into a regional watershed
restoration design that incorporates
landscape modification, stream
restoration/creation, and reforestation at
a head-of-hollow fill in eastern Kentucky.
Contributed by Patrick Angel, Ph.D,
DOI Office of Surface Mining
Reclamation and Enforcement
(pangel&.osmre. gov or 606-309-
4159) and Chris Barton, Ph.D
(barton&uky.edu or 859-257-2099)
and Carmen Agouridis Ph.D
(cagourid&bae.uky.edu or 859-257-
3000), University of Kentucky
Graded Spoil: DUncompacted • Loosely Compacted D Conventional
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£
350
300
250
200
150
100
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1997 1998 1999 2000 2001 2002 2003 2004 2005
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Solid Waste and
Emergency Response
(5203P)
EPA 542-N-08-004
July 2008
Issue No. 37
United States
Environmental Protection Agency
National Service Center for Environmental Publications
P.O. Box 42419
Cincinnati, OH 45242
Presorted Standard
Postage and Fees Paid
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Permit No. G-35
Official Business
Penalty for Private Use $300
Upcoming Conferences
The U.S. EPA and National Ground Water Association (NGWA) joint
Remediation of Abandoned Mine Lands Conference will be held October 2-
3, 2008, in Denver, CO. The agenda includes detailed discussion of
characterization, source controls, treatment technologies, and reuse/reclamation
strategies. More information and registration for this event is available from
the NGWA at http://www.ngwa.org/development/conferences.aspx.
The U.S. EPA and federal partners such as the Agency for Toxic Substances
and Disease Registry, National Institute of Health, and Department of
Energy will sponsor the International Environmental Nanotechnology
Conference: Applications and Implications on October 7-9, 2008, in
Chicago, IL. Presentations will address nanotechnology applications for
remediation of environmental contaminants, implications of releasing
manufactured nanoparticles in the environment, and pollution control and
nano-enabled sensing. Registration and a detailed agenda are available online
at http://emsus.com/nanotechconf/index.htm.
The Groundwater Resources Association of California (GRAC) will convene
its Emerging Contaminants 2008 Symposium on November 19-20, 2008,
in San Jose, CA. Topics will include nanomaterials, pesticides/herbicides,
Pharmaceuticals, phthalates, and flame/fire retardants. For more information,
visit GRAC online at http://www.grac.org/contaminants.asp.
Contact Us
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Technology News and Trends
welcomes readers' comments
and contributions. Address
correspondence to:
John Quander
Office of Superfund Remediation
and Technology Innovation
(5203P)
U.S. Environmental Protection Agency
Ariel Rios Building
1200 Pennsylvania Ave, NW
Washington, DC 20460
Phone:703-603-7198
Fax:703-603-9135
EPA is publishing this newsletter as a means of disseminating useful information regarding innovative and alternative treatment techniques and
technologies. The Agency does not endorse specific technology vendors.
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