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1. History/Background of the Source of the Abandoned Mine Lands Problem:
The Patoka South Fork
Watershed is part of the Patoka River Watershed. The Patoka River stretches
from Orange County, Indiana through Dubois, Pike, and Gibson Counties in
Southwestern Indiana before joining the Wabash River at Mt. Carmel,
Illinois. The drainage of the Patoka River Watershed includes 862 square
miles (551,680) acres in eight counties).
Major coal beds were discovered close to the surface
where the Patoka Valley flattens out about midway in it’s flow. Beginning
in 1836, underground coal mining became a major industry in Pike County. In
the 1920s, surface mining began to replace deep mining. During the next
fifty years, over 20,000 acres of Pike County were surfaced mined and left
abandoned and un-reclaimed, resulting in Acid Mine Drainage (AMD). These
conditions eradicated all fish in long stretches of the Patoka River, and
the entire length of the 17 mile long South Fork Tributary.
The South Fork of the Patoka River Watershed is
considered the most heavily impacted watershed in the State of Indiana. Of
the approximately 52,000 acre watershed, between 60 and 75 percent has been
impacted or impaired. The environmental degredation from AMD has been well
documented by numerous scientific studies. These studies have documented
the loss of fish, aquatic insects, and plants due to inflow of water with
low pH, heavy metals, suspended sediments, and precipitates that coat the
stream bottoms.
In August 1995, a group of concerned citizens joined
with local, state, and federal government representatives to sponsor a
public meeting. The goal of this meeting was to focus attention on the
problems of the Patoka South Fork Watershed., and to investigate what could
be done to improve the terrible conditions of the stream. The outgrowth
from this initial meeting of 125 participants (and seven follow-up meeting)
was the formation of the Patoka South Fork Watershed Steering Committee (PSFWSC).
The Committee is a true partnership of citizens and government agencies
working together towards a common environmental stewardship and improvement
within the watershed.
Initially, the PSFWSC focused upon building a strong
organization by electing officers, adopting by-laws, and establishing
procedures whereby the committee could carry out it's mission. On the basis
of this strong organization, the committee was successful in the
identification and pursuit of funding sources. They retained a full-time
Watershed Coordinator to assist with administration, planning, and location
characterization. The group began investigation of AMD flows into the
tributary. Initial priorities for potential projects were set within the
scope that the committee believed would be challenging, manageable, and
successful. The initial projects were then assigned to individuals as
"volunteer project managers" who agreed to shepherd the project through
investigation, design, and construction.
As the PSFWSC matured, the committee has been able to
successfully complete several AMD improvement projects within the
watershed. These successful projects have garnered media attention and
praise regarding both the employment of innovative techniques and the
partnering of concerned citizens with government agencies and private
industry.
2. Description of the Upper Thompson Run:
The Thompson Run flows from the Northeast area of the
watershed to the South Fork of the Patoka River. This stream carries the
most damaging flow in the entire watershed. The pH is often 3, or below.
The high metal concentrations produce large quantities of precipitates
immediately upon being aerated in a riffle or upon confluence with other
intermittent or perennial streams containing better quality water with some
alkalinity. The result is a continuous tide of precipitates and acid water
which sterilizes both Thompson Run and the South Fork of the Patoka.
The PSFWSC has studied Thompson Run since the
committee's organization in 1995. Generally, the source of the
contamination has been found to be acid seeps flowing to the channel. These
seeps are usually located at the toe of the spoil piles created by previous
mining. This is the case in this particular project. The water chemistry
of these seeps at the headwaters of Thompson Run has proved to be quite
challenging. With aluminum concentrations up to 60 PPM in some cases, any
attempt to use anoxic drains or related technology is doomed to failure.
Therefore, the PSFWSC has called upon several sources to propose a solution.
3. Description of the Plan:
The proposed project embraces a plan developed by the
committee's consultant and two university researchers who are well known in
the field of AMD treatment and prevention - Mr. Jack Nawrot of Southern
Illinois University, and Dr. Paul Ziemkiewicz of West Virginia University.
The plan incorporates a combination of techniques reported in " Nawrot, J.
R. and J.E. Sandusky. 1993. Concentrated Alkaline Recharge Pools for Acid
Seep Abatement: Principles, Design, Construction, and Performance. In
Proceedings NMLRC Symposium, 1993 Coal Res. Center, Nat. Mine Land
Reclamation Center SIUC."
In summary, the plan involves the addition of alkaline
material into three different types of structures. The alkaline material
will then percolate into the groundwater and neutralize the acid producing
material. Subsequently, the groundwater escaping through the seeps will no
longer contain the acidity and the metals so deleterious to the watershed.
By incorporating the three different types of treatment structures, the
PSFWSC will be able to further evaluate the effectiveness of each type,
which will be considered in future projects.
The alkaline material will be supplied by a corporate
partner of the PSFWSC, the AirGas Corporation.
AirGas is able to supply an unlimited amount of calcium
hydroxide suspension by tanker truck. This material is a by-product of the
manufacture of acetylene gas. It is not a hazardous waste. The PSFWSC has
previously been able to use this material in other projects. The use has
generally been limited to summer months as county road-weight restrictions
preclude the delivery during the winter. Since this project will be
accessed by state highway and private roads, it represents a unique
opportunity to make use of this valuable asset during the winter months. A
large portion of this project is the development of an additional access
road to bring the product to the points of application.
Since the project lies behind the Onyx Blackfoot
Landfill, most of the access will be via their existing roads. In addition
to access, this landowner and partner of the PSFWSC has agreed to provide
some durable fill material needed for road construction and to periodically
grade the road to insure all weather access as much as possible.
4. Future Plans:
Additional
work is needed in another branch of the headwaters of Thompson Run.
Additionally, further treatment by in-stream application of alkaline product
followed by a sedimentation/polishing pond is under consideration for the
main channel. The results of this project and any further projects will
continue to be monitored and evaluated in order to be able to transfer the
results to others working in AMD affected watersheds.
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