Transcript Slide 1

Treatment of Richard Mine
Acid Mine Drainage Project
2010 West Virginia Mine Drainage
Task Force Symposium
Morgantown, West Virginia
March 31, 2010
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Introduction
– GAI was retained by the West Virginia Conservation
Agency, Monongahela Conservation District with the
US Department of Interior, Natural Resources
Conservation Service as a review agency to perform
this project:
+ WVCA – Mike Sykes
+ NRCS – TJ Burr, P.E.
+ GAI Consultants, Inc. – James Hemme, P.E., L.R.S.
+ GAI Consultants, Inc. – Charles Straley, P.E., P.S.
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Richard Mine Location/Background
+ Originates from the abandoned
underground coal mine in the
Lower Freeport Coal located
near Morgantown, West Virginia
in the Deckers Creek
Watershed
+ Deckers Creek is a tributary of
the Monongahela River.
+ The primary discharge is
located in the community of
Richard, near the Intersection of
Interstate 68 and State Route 7,
southeast of Morgantown.
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Richard Mine Location/Background
Source
Date
Discharge
(gpm)
pH
Acidity
Conc.
(mg/L)
Load
(lb/day)
Al
Conc.
(mg/L)
Load
(lb/day)
Fe
Conc.
(mg/L)
Load
(lb/day)
Fe3+(%)
Mn
Conc.
(mg/L)
Load
(lb/day)
NRCS
10/23/1997
150
2.9
628
1132
84
151
147
265
17%
3.2
6
11/21/1997
6/25/1999
7/15/1999
8/17/1999
9/23/1999
150
135
136
122
138
3.1
3.59
3.55
3.6
3.63
818
1020
1210
1140
1250
1475
1658
1978
1674
2076
46
95
88
78
61
83
155
143
115
101
171
114
201
205
209
308
185
329
301
346
15%
Stewart
and
Skousen
3.7
4.3
4.3
4.3
3.9
7
7
7
6
6
10/25/1999
120
3.95
1145
1657
62
90
193
279
3.9
6
11/20/1999
101
3.96
1024
1243
68
83
218
265
4.5
5
12/21/1999
1/31/2000
2/24/2000
3/31/2000
4/25/2000
5/24/2000
6/21/2000
7/26/2000
8/24/2000
9/20/2000
98
135
4.07
4.15
3.97
3.89
3.66
4.2
3.48
3.58
3.89
3.97
998
1040
618
881
885
650
930
917
1017
1297
1178
1683
60
62
60
55
80
82
72
82
71
63
71
100
200
182
115
96
148
190
176
172
178
167
236
294
3.9
3.6
3.1
2.7
3.5
4.5
3.7
3.8
3.9
3.6
5
6
10/29/2001
10/3/2001
WVDEP
5/6/2003
6/6/2005
Mack
1/13/2006
and
2/1/2006
Skousen
2/10/2006
2/17/2006
3/16/2006
4/2/2006
4/14/2006
GAI
6/15/2006
Mininum
Maximum
Average
214
78
76
68
73
57
60
200
68
57
57
48
68
46
95
68
615
406
282
332
308
71
615
226
Christ
122
123
572
233
336
224
310
260
735
NM
794
754
594
412
576
377
98
794
305
4.1
4.2
4.2
3.9
3.77
NM
3.7
3.95
4.2
4.3
4.3
3.79
2.9
4.3
4
1289
1313
4468
2605
4105
3491
930
2391
791
866
3224
595
1861
922
8132
673
NO LAB DATA RECEIVED
799
7229
810
5774
965
4771
826
5709
667
3018
595
1132
1297
8132
907
3005
81
119
567
202
286
170
257
227
503
233
204
180
174
151
156
164
140
147
136
179
96
233
171
140
220
1304
493
719
448
600
678
544
1332
1484
998
727
940
810
140
1484
570
12%
4%
36%
-
4%
36%
0
4
5
31
10
16
10
5
5.1
3.4
3.7
10.2
3.3
13
3.57
2.91
3.12
2.84
3.2
2.7
10.2
4
32
21
15
20
14
4
90
15
13
11
90
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Richard Mine Location/Background
+ The Richard Mine delivers the single greatest AMD contribution to
Deckers Creek in its entire length. It loads Deckers Creek with
Aluminum, Iron and Manganese at rates of 59,000, 143,000 and
3,200 lbs/yr, respectively.
+ The primary discharge from the Richard Mine contributes a relatively
small amount of flow compared to the flow in Deckers Creek.
+ Measurements of the flow from the Richard Mine range from 0.22 to
1.77 cfs with an average less than 0.7 cfs, whereas estimates for the
flow of Deckers Creek under the bridge at Dellslow, just upstream of
the Richard Mine discharge, range from 1.9 to 119 cfs
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Richard Mine Location/Background
+ The aluminum and the ferric
iron contributed by the
primary discharge rapidly
precipitate in the stream bed
as a result of the oxidation
reactions.
+ The heavy multicolored
precipitates are responsible
for diminishing aquatic
habitat and limiting stream
uses in this reach.
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Richard Mine Location/Background
+ The abrupt change in
appearance in Deckers Creek
at its confluence with the
primary discharge for Richard
Mine is evidence of the
dramatic change in the
streams chemistry.
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Project Goals
+ The goal of the Project is to
implement a solution that will
result in improved water quality
in Deckers Creek and possibly
allow it to be suitable for
sustaining warm water fish and
other aquatic life.
+ By analyzing the AMD
associated with the primary
discharge, it is then possible to
develop a comprehensive list
of alternatives to potentially
mitigate the AMD problem.
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Evaluation Report
+ Comprises of a compilation of data from the review as well as an
+
evaluation/ assessment of the data for completeness and
application to the Project.
The purpose of the Project is to identify treatment alternatives for
the AMD problem, and to design a construction project to
potentially reduce / eliminate the AMD contaminated water from
entering Deckers Creek or to improve the water quality of the
AMD so that it does not degrade the water quality in Deckers
Creek.
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Geologic Setting
+ The geology of the Deckers
Creek watershed is part of the
Pennsylvanian Period, namely
the Monongahela, Conemaugh,
and Pottsville Groups and the
Allegheny Formation.
+ The dominant rock types include
sandstone, siltstone, shale,
limestone, and coal.
+ The mined coal interval is the
Upper Freeport Coal.
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Geologic Setting
+ The primary discharge is located 1-1/2 miles southeast of the
+
+
+
+
+
Connelsville Uniontown Syncline.
The rock dips to the northwest at approximately 565 feet per mile.
The Upper Freeport coal in the Richard Mine is only four feet high and
lies at a relatively steep slope of approximately 8 percent.
The Upper Freeport Coal seam is the topmost strata of the Allegheny
Formation of the Pennsylvania System.
The overlying strata in the Conemaugh Group contains several massive
sandstones and some shales.
Limestone or alkaline-bearing rock units are not generally found within
50 meters above the Upper Freeport Coal in this area.
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Mining Discussion
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Hydraulics and Hydrology
+ A hydrology and hydraulics evaluation of the mine area was
+
+
performed in order to characterize potential inflow and outflow
points.
The intent of this evaluation is to provide insight into the possible
source(s) of water infiltrating the mine and locations of discharge
other than the primary discharge. Having an understanding of
where the water within the mine originates and culminates allows
for a better comprehension of the impacts of the water.
The Upper Freeport Coal seam outcrops along the eastern and
southern portion of the mine workings and is significantly below
drainage as the mine workings progress to the West.
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Hydraulics and Hydrology
+ On the western edge of the mine workings, the coal seam is at
+
+
approximate elevation of 700 to 750 feet which is approximately
300 to 400 feet below the ground surface.
The water elevation of Cheat Lake is approximately 870 feet and
the Monongahela River is at approximate elevation 814 feet.
These elevations are lower than the closest portion of the mine
workings. Therefore, it is unlikely that they have any effect on
the mine drainage.
A portion (approximately one-half of the mine workings area) has
a local dip to the South. Thus, a mine discharge occurs along
the southern edge of the mine workings (i.e., at the primary
discharge).
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Hydraulics and Hydrology
+ “Rules of thumb” are often used to assess the reasonableness of
+
+
+
the yield relationship.
Typically, the anticipated range of values would be from 0.25
gallon/minute/mine acre to 2.0 gallon/minute/mine acre in high
flow situations.
The area of the Richard Mine and associated documented
adjacent mining encompasses approximately 2,200 acres.
Utilizing the 0.25 gpm/acre flow value, it could be anticipated that
the flow rate in the mine from infiltration would be 550 gpm.
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Hydraulics and Hydrology
+ The primary discharge constitutes over 90% - 95% of the flow
+
+
+
from the Richard Mine (based upon visual observations of the
mining limits).
The range of flow from the primary discharge is 98 gpm to 794
gpm.
The anticipated infiltration rate compared to the primary
discharge flow rates confirms the previous assessment that the
surface waters overlying the Richard Mine are not contributing to
the flow from the mine.
The flow from the Richard Mine is well within the range of the
anticipated flow from infiltration.
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Water Quality Analysis
+ Characterization of the primary discharge from the Richard Mine
+
+
+
is critical.
The mine water at the seal is in an anoxic state with only a
limited concentration of dissolved oxygen, making it amenable to
some form of amelioration by sulfate reducing bacterial, were the
flow much smaller and area available.
This characteristic also is amenable to pumping the mine pool to
prevent a gravity discharge.
Pumping the pool is preferable to collecting the flow after
discharge in that it minimizes the dissolved oxygen in the
associated pipes and reduces maintenance.
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Treatment Alternatives
+ A cursory review of a partial list of treatment technologies
+
+
permits the evaluation of the adequacy of the data.
A detailed analysis of the technologies / alternatives was
conducted during subsequent phases of the Project.
A bench scale test was conducted to provide additional data
pertaining to the primary discharge.
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Conclusions
+ The intentions of the “Evaluation Report” were to compile the
+
+
available data into a concise source, provide some insight to the
possibility of treatment of the AMD from the Richard Mine, and
evaluate the adequacy of the data.
Due to the lack of subsurface information on the Richard Mine,
more detailed studies would need to be conducted, including but
not limited to, mine pool elevation investigation and actual coal
elevation and dip studies.
The flow rate of the primary discharge and other discharges
should be monitored on a consistent basis to determine
which of the data is representative of the discharge.
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Conclusions
+ The combination of the evaluation report and the bench scale
+
testing provides the basis needed to conduct an alternative
analysis for the potential reduction / elimination of the AMD
discharge from the Richard Mine.
The next phase of the project ,“Compilation of AMD Treatment
Alternatives,” will provide the detailed information required for a
determination of options for treatment of the AMD from the
Richard Mine.
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Flow Monitoring Study
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General Location Map
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Flow Rate vs. pH
Richard Mine 2008
Hi-lighted areas signify poor data due to equipment issues
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Flow Rate vs. Temp.
Richard Mine 2008
Hi-lighted area shows inaccurate data as the probe was exposed to air
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Flow vs Rain Gage 1
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Flow vs Rain Gage 2
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Flow vs Morgantown Locks and Dam Gage
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Flow vs Morgantown Airport Rainfall Gage
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Flow vs Average Rainfall (4 gages)
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Rainfall Comparison
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Rainfall Comparison
+ June and July spike in precipitation
June 4th – 0.47” of rain followed by June 5th with 1.40”
June 14th – 0.72” followed by June 15th with 1.40”
July 4th – 1.0” followed by July 5th with 2.27”
July 21st – 0.83” followed by 0.72”,1.13” and 0.70” on 22nd to 24th.
+ Precipitation spike with no increase in flow.
Runoff?
Evapotranspiration?
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Infiltration Discussion
+ The 1900 acre footprint consists of:
800 acres of Woodland in Good Condition
900 acres of Meadow, Pasture or Open Space
200 acres of Residential Development (1/2 acre lots)
+
+
+
+
Surface Topography: 4% to 25% slopes – Headwater Area
Steep Cliffs on East and South Side
Geologic Fault to the North
Dip to the Northwest
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Infiltration Discussion
+ Approximately a 40/60 split of Type B and Type C Soils on the
surface above the mine.
+ Type B – Silt/clay/sandy loams or silty sands that have moderate
runoff potential and moderate infiltration. Typically more than 6
feet to bedrock in this region
+ Type C – Sandy or silty clays that have high runoff potential and
low infiltration rates. Typically bedrock is less than 6 feet below
the surface in this region.
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General Mine Data
+ Footprint of Mine = 1900 acres +/- (2.96 square miles)
+ Draining Toward Primary Outlet = 1500 acres +/- (2.34 sq. mi.)
+ Footprint of Mine Pool = 800 acres +/- (1.25 sq. mi.)
+ Volume of Mine Pool = 782 million gallons +/+ Volume per Foot of Elevation = 4.8 million gallons +/+ Average Slope of Mine Floor = 8-10% (est from mapping)
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Discussion of Flow Rates for 2008
+ Average = 401 gallons per minute or 0.89 cubic feet/second
+ Minimum = 167 gpm (Nov 11) or 0.37 cubic feet/second
+ Maximum = 662 gpm (Feb 15) or 1.48 cubic feet/second
General Rule of Thumb for Base Flow from Infiltration has been
0.25 gpm/acre to 2.0 gpm/acre.
Average Flow = 401 gpm/1500 acres = 0.26 gpm/acre
Minimum Flow = 0.11 gpm/acre
Maximum Flow = 0.44 gpm/acre
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Extrapolations from 2008 Data
 Average Flow Rate = 401 gallons per minute
Yearly Volume = 401 gpm x 60min/hr x 24 hr/day x 365 days/ yr
= 210,765,600 gallons per year
 Rainfall (Avg. of 4 stations) = 44.78 inches
Volume to Rainfall Ratio = 210,765,600 gallons / 44.78 inches
= 4,706,690 gallons per inch of rainfall
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Extrapolations from 2008 Data
 Mine Surface Area = 1500 acres
Unit Area per Inch = 4,706,690 gallons/inch / 1500 acres
= 3138 gallons/inch/acre (3630 gal/in/ac is 100% infiltration)
= (for the year 85% infiltration/evapotranspiration, 15% runoff)
 Average Rainfall = 43 inches
Yearly Unit Area Production = 3138 gal/ac/in x 43 inches
= 134,934 gallons/acre/year
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Questions/Comments
Thank You!