GROUP II,
Development Document for
interim Final Effluent Limitations Guidelines
and New Source Performance Standards
for the
COAL MINING
Point Source Category
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
OCTOBER 1975
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DEVELOPMENT DOCUMENT
for
INTERIM FINAL EFFLUENT
LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
for the
COAL MINING
POINT SOURCE CATEGORY
Russell Train
Administrator
Andrew W. Breidenbach, Ph.D.
Acting Assistant Administrator for
Water and Hazardous Materials
Allen Cywin
Director, Effluent Guidelines Division
Baldwin M. Jarrett
Project Officer
October 1975
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
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ABSTRACT
This document presents findings of an exhaustive study of
the coal mining and coal preparation industries for the
purpose of developing effluent limitations guidelines and
standards of performance for new sources to enable
implementation of Sections 304, 306, and 307 of the Federal
Water Pollution Control Act Amendments of 1972.
Effluent limitations guidelines contained herein set forth
the degree of reduction of pollutants in effluents
achievable by application of the "best practicable control
technology currently available" and the "best available
technology economically achievable." These standards must be
attained by existing point sources by July 1, 1977 and July
1, 1983, respectively, standards of performance for new
sources contained herein set forth the degree of reduction
of pollutants in effluents which is achievable through
application of the "best available demonstrated control
technology, processes, operating methods, or other
alt erna tives."
This report details findings, conclusions, and recommenda-
tions on control and treatment technology relating to waste
water from coal mines and coal preparation plants.
Supporting data and rationale for development of the
proposed effluent limitations and standards of performance
are contained herein.
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Contents
Section Page
I CONCLUSIONS 1
II RECOMMENDATIONS 5
III INTRODUCTION 9
Purpose 9
Summary of Methods used for 10
Development of Effluent Limitations
Guidelines and Standards of
Performance
Description of American Coal Fields 13
Description of Facets of the Coal 28
Industry
Coal Mining 28
Coal Mining Services or Coal 35
Preparation
IV INDUSTRY CATEGORIZATION 47
V WASTE CHARACTERIZATION 51
VI SELECTION OP POLLUTANT PARAMETERS 61
Constituents Evaluated 61
Guidelines Parameter Selection 61
Criteria
Major Parameters - Rationale for 61
Selection or Rejection
VII CONTROL AND TREATMENT TECHNOLOGY 73
Control Technology 73
Treatment Technology
VIII COST, ENERGY AND NON-WATER QUALITY 173
ASPECTS
Mine Drainage Treatment 173
Preparation Plant Water Reciruclation
IX BEST PRACTICABLE CONTROL TECHNOLOGY 18?
CURRENTLY AVAILABLE, GUIDELINES AND
LIMITATIONS •
X BEST AVAILABLE TECHNOLOGY ECONOMICALLY 209
, ACHIEVABLE, GUIDELINES AND LIMITATIONS
XI NEW SOURCE PERFORMANCE STANDARDS AND 215
PHETREK1MENT STANDARDS
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XII ACKNOWLEDGEMENTS 219
XIII BIBLIOGRAPHY 229
XIV GLOSSARY 243
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List of Figures
Figure Page
1 Coal Deposits in the United States 16
2 Anthracite and Lignite Coal Deposits 17
3 Bituminoius and Subbituminous coal Deposits 17
1 Contour Stripping 34
5 Area Mining with Successive Replacement 36
6 Stage 1 - Coal Preparation Plant 39
7 Stage 2 - Coal Preparation Plant 41
8 Stage 3 - Coarse Coal Preparation Plant 43
9 Stage 3 - Fine Coal Preparation Plant 44
10 Stage 3 - Coal slime Preparation Plant 45
11 Cross Section of Box Cut 74
12 Block-Gut 76
13 Ctoss Section of Non-Contour Regrading 78
14 Typical Head-of-Hollow Fill 79
15 Cross Sections - Typical Head-of-Hoilow Fill 80
16 Water Diversion and Erosion Control 83
(Contour Regrading)
17 Borehole and Fracture Sealing 91
18 Water Infiltration Through Unregraded 91
Surface Mine
19 Preplanned Flooding 92
Schematic Diagrams for Treatment Facilities
20 Mine A-l 101
21 Mine A-2
vi 1
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22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
Mine A- 3
Mine A- 4
Mine B-2
Mine D-3
Mine D-4
Mine E-6
Mine F-2
Mine K-6
Mine K-7
Mine D-l
Mine D-5
Mine J-2
Mine J-3
Mine F-8
Mine D-6
Mine N-6
Mine 0-5
Mine W-2
107
HO
U3
116
119
122
125
128
134
13I
147
150
153
157
160
l63
166
flO Construction cost vs. Capacity - Acid Mine 180
Drainage Treatment Plants
1 89
Ql Historical Data - Monthly Total Iron -
Treatment Plant A-l (1969 - 1971)
H2 Historical Data - Monthly pH - 190
Treatment Plant A-l (1969 - 1971)
13 Historical Data - Monthly Total Iron - 191
Treatment Plant A-l (1972 - 197i»)
HH Historical Data - Monthly pH - 192
vi 11
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Treatment Plant A-l (1972 - 197U)
US Historical Data - Monthly Total Iron - 193
Treatment Plant A-3 (1969 - 1971)
U 6 Historical Data - Monthly pH -
Treatment Plant A-3 (1969 - 1971)
*7 Historical Data - Monthly Total Iron
Treatment Plant A-3 (1972 - 197U)
U 8 Historical Data - Monthly pH - 196
Treatment Plant A-3 (1972 -
9 Historical Data - Daily Total Iron - 197
Treatment Plant K-7 (1973 - 197U)
±x
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List of Tables
Table Page
1 Raw Wine Drainage Characteristics - Underground 56
Mines - Alkaline
2 Raw Mine Drainage Characteristics - Underground 57
Mines - Acid or Ferruginous
3 Raw Mine Drainage Characteristics - Surface Mines - 58
Acid or Ferruginous
4 Raw Mine Drainage Characteristics - Surface Mines - 59
Alkaline
5 Raw Waste Characteristics - Coal Preparation 60
Plant Effluent
6 Potential Constituents of Coal Industry 61a
Waste water
7 Analytical Data - Mine Code A-l 102
8 Analytical Data - Mine Code A-2 105
9 Analytical Data - Mine Code A-3 108
10 Analytical Data - Mine code A-* HI
11 Analytical Data - Mine Code B-2 H4
12 Analytical Data - Mine code D-3 117
13 Analytical Data - Mine Code D-* 120
14 Analytical Data - Mine Code E-6 123
15 Analytical Data - Mine Code F-2 126
16 Analytical Data - Mine Code K-6 I2g
17 Analytical Data - Mine Code K-7 132
18 Analytical Data - Mine code D-l
19 Analytical Data - Mine Code D-5 138
xi
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20 Analytical Data - Mine Code J-2 148
21 Analytical Data - Mine Code J-3 151
22 Analytical Data - Mine Code F-8 154
23 Analytical Data - Mine Code D-6 158
24 Analytical Data - Mine Code N-6 !5l
25 Analytical Data - Mine Code U-5 164
26 Analytical Data - Mine Code W-2 167
27 Water Effluent Treatment Costs - Coal Mining
Industry - Acid Mine Drainage Treatment
Plants
28 Water Effluent Treatment Costs - Coal Mining
Industry - Acid Mine Drainage Treatment
Plants
29 Water Effluent Treatment Costs - coal Mining
Industry - Acid Mine Drainage Treatment
Plants
30 Typical Construction Costs - Acid Mine
Drainage Treatment Plants
31 Coal Preparation Plant Water Circuit
Closure Cost
32 Winter-Spring (1975) Analytical Data 201
33 22 Best Plants (1974) Analytical Data 202
34 Effluent Levels Achievable Through Application 207
of the Best Practicable Control Technology
Currently Available
35 Effluent Levels Attainable Through Application 212
of the best Available Technology Economically
Achievable
36 New Source Performance Standards 21
37 Conversions Table - English to Metric
247
xll
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SECTION I
ODNCLUSICNS
Based on the findings of this study, the following conclu-
sions have been made:
The ooal industry point source category was divided into two
subcategories - ooal production and ooal preparation - for
the purpose of establishing effluent limitations and
standards of performance.
Pollutant parameters whose concentrations most frequently
exceed acceptable levels in waste water from coal production
facilities are: acidity, total iron, dissolved iron,
manganese,, aluminum, nickel, zinc/ total dissolved solids,
total suspended solids, sulfates, ammonia, fluorides, and
strontium.
Concentrations of fluoride, strontium, ammonia, and sulfate,
although occasionally above accepted standards, are not
normally high enough to have deleterious effects. In
addition, the cost of technology for reduction of these
constituents in the concentrations observed is not
considered feasible. Total dissolved solids pose a similar
problem as the cost of the technology does not warrent the
reduction obtained.
Pollutant parameters whose concentrations most frequently
exceed acceptable levels in waste water from the coal
preparation subcategory of the industry include: total
iron, dissolved iron, total dissolved solids, total
suspended solids, and sulfates.
Subcategorization of the coal production portion of the
industry is limited to differentiation between acid or
ferruginous drainage and alkaline drainage, which in turn
reflects local or regional coal and overburden conditions;
and is directly related to the treatment technology
required. Alkaline drainage is most frequently found in the
Interior and Western coal fields and is generally
characterized only by total dissolved and suspended solids
in excess of acceptable levels. Acid or ferruginous
drainage, typically found in Northern Appalachia, exhibits
high concentrations of all critical parameters defined in
this report (see Section VI),
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Generally, water quality analyses indicated no significant
differences between untreated waste water from surface and
underground mining operations in similar geologic settings.
Several parameters namely total and dissolved iron and total
suspended solids did vary within the classes of mine
drainage, however, this is believed to be the result of
precipitation patterns. (heavy rainfall on surface mines).
The most serious water related mining problem associated
with development of western coal fields appears to be
disruption of aquifers resulting in lowered water tables and
well levels.
The coal production segment of the industry has already
developed technology to solve its most serious waste water
problem: neutralization of acidity with concurrent reduction
of other pollutants to safe concentrations. This is usually
achieved with lime neutralization followed by aeration and
sedimentation.
Other reagents occasionally utilized by the coal industry
for neutralization include limestone, caustic soda, soda
ash, and anhydrous ammonia. Anhydrous ammonia can result in
eutrophication of receiving waters if used for prolonged
time periods or relatively high mine drainage volumes.
Mine drainage neutralization treatment plants can
successfully control acidity, iron, manganese, aluminum,
nickel, zinc, and total suspended solids.
While neutralization successfully controls most acid mine
drainage pollutant parameters, final effluents frequently
contain suspended solids in excess of those exhibited by
unneutralized settling pond effluent (alkaline mine
drainage). This occurs for two reasons: 1) physical
addition of solids (neutralizing agents) during the
treatment process; and 2) the increased pH resulting from
the neutralization process initiates precipitation of
previously dissolved constituents.
Operating costs of mine drainage neutralization plants are a
function of the volume treated. As a result, operating
costs were found to vary from 3 to 10 cents per thousand
liters (11 to t*0 cents per thousand gallons) .
Neutralization plant construction costs were found to have
an inverse relationship to the volume of drainage being
treated. All plants must provide the same essential
equipment including lime storage, feeders, control
facilities, and housing regardless of the flow encountered.
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Associated facilities such as aeration basins and settling
ponds have a proportional increase in cost with an increase
in flow. Settling ponds construction cost for alkaline mine
drainage have a direct relationship to flow or volume
treated.
The coal production portion of the industry has also
controlled a second serious waste water problem - the
presence of excessive total suspended solids in both
alkaline drainage and acid or ferruginous drainage - through
utilization of settling basins and coagulants prior to the
discharge of mine waters. The concentrations of suspended
solids in the final effluent can be further reduced through
deep bed, mixed media filtration. Although such filtration
techniques have not been demonstrated in the coal industry,
the technology has been used extensively in other industries
for removal of total suspended solids.
The only adverse nonwater quality environmental factors
associated with treatment of waste waters from the coal
industry are occasional monopolization of otherwise pro-
ductive land for treatment facility siting and disposal of
solid waste (sludge) generated during the treatment process.
Routine maintenance and cleaning of sedimentation basins is
essential to efficient operation. Accumulated sludge can
actually increase effluent suspended solids concentrations
above influent concentrations, particularly in surface
mining operations during periods of heavy rainfall.
Sedimentation ponds installed for "polishing11 otherwise
acceptable drainage can result in increased total suspended
solids loadings as a result of carry-over of algae blooms in
the final effluent, such basins are not installed unless
warranted by degraded water quality, or for flow
equalization.
Control of waste water pollution from surface mines is
successfully achieved by implementation of effective mining,
regrading, water diversion, erosion control, soil
supplementation and revegetation techniques. These control
techniques may be augmented with treatment techniques
including neutralization plants or sedimentation basins
during mining and reclamation.
Infiltration control can occasionally reduce the volume of
waste water discharged from active underground mines and is
achieved by implementation of mine roof fracture control
including the design of the mine's pillars and barriers,
sealing of boreholes and fracture zones, and backfilling of
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overlying abandoned surface mines. Concentration of
pollutants is also significantly reduced by limiting the
contact time of the waste water within the mine workings,
control of waste water pollution on closure of underground
mines can be affected with proper mine sealing.
Through a combination of efficient plant design, inprocess
controls and end-of-process treatment, coal preparation
plants can utilize a closed-water circuit and, therefore,
achieve zero discharge of waste water. This was
demonstrated at the majority of the coal preparation plants
visited during this study.
Waste water from coal preparation plant ancillary areas,
including coal storage areas and refuse storage areas, is
controlled and treated with techniques similar to techniques
employed by surface mines.
Dust presents a temporary nonwater environmental problem
during mining and reclamation,in western coal fields. The
impact of this temporary aspect is reduced by the fact that
most western mine developments are in sparsely populated
regions. Dust problems also occur in Eastern and Interior
coal fields where dust occasionally blows from trucks and
railroad cars.
Waste loads from coal production are unrelated, or only
indirectly related, to production quantities. Therefore
effluent limitations are expressed in terms of concentration
rather than units of production.
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SECTION II
RECOMMENDATIONS
Extensive study of all existing methods for the treatment of
coal industry waste water indicates that the best
practicable control technology currently available is in
widespread use by the coal industry.
Based upon the information obtained in the study and
presented in this report, the following effluent limitations
guidelines are recommended for the major categories of the
coal industry. Since data analyzed during this study
indicated no significant differences in each of the raw mine
drainage categories, bituminous and lignite mining and
anthracite mining categories are combined, as are bituminous
and lignite mining services and anthracite mining services.
Separate standards are proposed for suspended solids
limitations in alkaline mine drainages since lower
concentrations can be achieved in unneutralized alkaline
drainages.
EFFLUENT LEVELS ACHIEVABLE THROUGH APPLICATION OF THE
BEST PRACTICABLE CONTROL TECHNOLOGY CURREWHY AVAILABLE
Parameter
Bituminous, Lignite, and Anthracite
Mining Set-vices
Bituminous, Lignite, and
Anthracite Mining
Coal Preparation
Plant
Coal Storage,
Refuse Storage
and Coal Prep-
aration Plant
Ancillary Area
Acid or Ferrugi-
nous Mine-Drainage
Alkaline Mine
Drainage
30 Day Daily 30 Day * Daily * 30 Day * Daily * 30 Day.* Daily *
Average Maximum Average Kairauro Average Maximum Average Maximum
PH
IROM, TOTAL
DISSOLVED IROM
ALUMINUM,.TOTAL
MANGANESE, TOTAL
NICKEL, TOTAL
ZINC, TOTAL
TOTAL SUSPENDED
SOLIDS
t.
o
Q
u
2
o-
u
I/I
s.
2
s .
VI
*/»
o
o
t.
V-
0
01
a
•5
VI
5
Si
6-9
3,5
0.30
2.0
2,0
0,20
0.20
35
6-9
7.0
0,60
4;0
4,0
0,40
0.40
70
6-9
3.5
0.30
,2.0
2.0
0.20
0.20
35
6-9 6-9
7,0
4.0
4.0
3.5
0.60 0.30
2.0
2.0
0.40 0.20
6-9
7.D
0.60
4.0
4.0
0.40
0-.40 0,20 0.40
70 25 50
*A11 values except pH in rag/1.
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BAT effluent limitations are based on iirpletnentation of the
best control or treatment technology orployed by a specif ic
point source, or readily transferable from one industry
process to another. Although economically achievable
technology does not exist for significant reduction of
additional pollutant parameters, design refinements and
better control of the treatment operation can result in
lower ooncentrations of those parameters controlled with BET
technology. Also, the state-of-the-art has been developed
and is in use in other industries for further reduction of
suspended solids concentrations. Based upon the information
presented in this report, a determination has been made that
the reduction of pollutants attainable through application
of the best available control technology economically
achievable is presented below.
EFFLUENT LEVELS ATTAINABLE THROUGH APPLICATION OF THE
BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
Parameter
Bituminous, Lignite, and Anthracite
Mining Services
Bituminous, Lignite, and
Anthracite Mining
Coal Preparation
Plant
Coal Storage,
R^/use Storage
and Coal Prep-
aration Plant
Ancillary Araa
Acid or Ferrugi-
nous Mine Drainage
Alkaline Mine
Drainage
30 Day Daily 30 Day * Daily * 30 Dey * ' Daily * 30 Day * Daily *
Average Maximum Average Maximum Average Maximum Average Kaxisnrai
PH
IROIJ, TOTAL
DISSOLVED IfiOS
ALUMISUH, TOTAL
KANGAKESE, TOTAL
81CKR. TOTAL
u
o
v.
o.
ej
a
o
0
E1
6-9
3.0
0.30
2.0
2.0
0.20
6-9.
3.5
0.60
4.0
4.0
0.40
6-9
3.0
0,30
2.0
2.0
0.20
6-9 6-9
3.5 3.0
0.60 0.30
4.0
4.0
2.Q
2.0
0.40 0.20
6-9
3.5
0.60
4.0
4.0
O.AO
ZINC, TOTAL
TOTAL SUSPENDED
SOLIDS
0.20 -0.40 0.20 0.4D 0.20 0.10
20 40 20 40 20 40
*A11 values except pH 1n rag/1,
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The filtration technology upon which BUT suspended solids
limitations were based has not been applied in a coal
industry operation, thus its adaptabilityt suitability, and
economics have not yet been fully demonstrated. It is
recommended that New Source Performance Standards for the
coal industry be the same as those identified for BAT,
except for suspended solids which shall be the same as for
BPT-
Parameter
SOURCE PERFORMANCE STANDARDS
, lignite, and Anthracite
Mining Services
Bituminous, Lignite, and
Anthracite Mining
Coal Preparation
Plant
Coal Storage,
Refuse Storage
and Coal Prep-
aration Plant
Ancillary Area
Acid or Ferrugi-
nous Mi/IB Drainage
Alkaline Hine
Drainage
30 Day Dally 30 Day * Daily * 30 .Day * Daily *. 30 Day * Daily *
Average • Maximum Average Maximum Averege- • Maximum" Average Maximum
pH
IflOH, TOWL
DISSOLVED IRON .
ALlffilKUK, .TOTAL
MAKSANESE, TOTAL
NICKELt TOTAL
ZINC, TOTAL
TOTAL SUSPENDED
SOLIDS
(.
Of
5:
Vt
ra
u
o
(X
4-
e>
&
ff
o
u
S
t,
01
a
**
u
Ck
o
01
l>
w
*f"
5
&
6-9
3.0
0:30'
2.0
2.0
0.20
0.20
35
6-9
3.5
o.so
4.0
4.0
0.40
0.40
70
6-9
3,0
0.30
2.0
2.0
0,20
0.20
35
6-9 6-9
3.S 3.0
0,60 0.30
4.0
2.0
4.0 2.0
0.40 0.20
6-9
3.S
0.60
4.0
4.0
0.40
0.40 0.20 0,40
70 25 50
*A11 values except pH in ng/1,
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In order to assure maximum efficiency and continual
operation, it is recommended that adequate safeguards be
incorporated at critical locations throughout each mine
drainage treatment plant. These safeguards should consist
of automatically pH-adjusted feed controls and effluent
monitors equipped with emergency alarms and shutdown
features. Turbidity meters should continually monitor
settling pond effluent drainage to reduce the possibility of
accidental discharge of excessive concentrations of
suspended solids. Such instrumentation requires attention
to plant maintenance to assure effective operation.
An inventory should be maintained of critical or hard to
locate parts, and emergency auxiliary units should be
readily available. Storage should be provided for adequate
supplies of raw materials (neutralizing reagents), and
alternative sources of supply should be identified.
Operating schedules should include adequate time for
preventive maintenance, including routine cleaning of sludge
ponds and basins, to insure adequate detention and to
prevent carryover of accumulated solids.
8
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SECTION III
INTRODUCTION
PURPOSE
The Federal Water Pollution Control Act Amendments of 1972
require the United States Environmental Protection Agency to
establish effluent limitations which must be achieved by
point sources of discharge into the navigable waters, or
tributaries of navigable waters of the United States.
Specifically, Section 301 (b) of the Act requires achieve-
ment by not later than July 1, 1977, of effluent limitations
for point sources, other than publicly owned treatment
works, which are based on implementation of the "best
practicable control technology currently available" as
defined by the administrator pursuant to Section 304 (b) of
the Act. Section 301 (b) further requires achievement by
not later than July 1, 1983, of effluent limitations for
point sources which are based on application of the "best
available technology economically achievable". This will
result in further progress toward the National goal of
eliminating discharge of all pollutants. Section 306 of the
Act requires achievement by new sources of control of
discharge reflecting the application of the "best available
demonstrated control technology, processes, operating
methods, or other alternatives, including, where
practicable, a standard permitting no discharge of
pollutants."
Within one year of enactment, the Administrator is required
by Section 301 (b) of the Act to promulgate regulations
providing guidelines for effluent limitations setting forth:
1. The degree of effluent reduction attainable through
application of the best practicable control
technology currently available.
2. The degree of effluent reduction attainable through
application of the best control measures and
practices achievable (including treatment
techniques, process and procedure innovations,
operation methods, and other alternatives).
The regulations proposed herein set forth effluent
limitation guidelines pursuant to Section 30H (b) of the Act
for coal industry point sources in anthracite mining and
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mining services and bituminous and lignite mining and- mining
services.
Section 306 of the Act requires the Administrator, within
one year after a category of sources is included in a list
published pursuant to section 306 (b) (1) (A) of the Act, to
propose regulations establishing Federal standards of
performance for new sources within such categories. The
Administrator published, in the Federal Register of January
16, 1973 (38FR 16 21) a list of 27 source categories.
Publication of an amended list will constitute announcement
of the Administrator's intention of establishing under
Section 306 standards of performance applicable to new
sources within the coal mining industry. The list will be
amended when interim final regulations for the coal mining
industry are published in the Federal Register.
The guidelines in this document identify in terms of
chemical, physical, and biological characteristics of
pollutants, the level of pollutant reduction attainable
through application of the best practicable control
technology currently available. The guidelines also
consider a number of other factors, such as the costs of
achieving the proposed effluent limitations and nonwater
quality environmental impacts (including energy
requirements) resulting from application of such
technologies.
SUMMARY OF METHODS USED FOR DEVELOPMENT OF EFFLUENT
LIMITATIONS GUIDELINES AMD STANDARDS OF PERFORMANCE
The effluent limitations guidelines and standards of
performance proposed herein were developed in a series of
systematic tasks. The Coal Industry was first studied to
determine whether separate limitations and standards are
appropriate for different segments within the point source
category. Development-of reasonable industry categories and
subcategories, and establishment of effluent guidelines and
standards requires a sound understanding and knowledge of
the Coal Industry, the processes involved, waste water
generation and characteristics, and capabilities of existing
control and treatment methods.
Initial categorizations and subcategorizations were based on
the suggested Standard Industrial Classification Groups
(SIC) which categorize the mining and preparation segments
of the industry and on such factors as type of mining
operation (surface mine/underground minej, geographic
location, size of operation, and rank of coal mined
(anthracite/bituminous/lignite).
10
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On-site visits and interviews were made at selected surface
mines, underground mines, and coal preparation plants
throughout the United states to gather new data and to
confirm and supplement compiled data. All factors
potentially influencing industry subcategorization were
represented at the selected sites. Detailed information on
production, water use, waste water control practices, and
waste water treatment practices was obtained. Flow diagrams
were prepared indicating the course of waste water streams.
Control and treatment plant design and cost data were
compiled. Raw and treated waste water streams were sampled
and analyzed and historical effluent quality data was
obtained wherever possible. Duplicate samples were analyzed
by the National Coal Association to confirm the analytical
results.
Raw waste characteristics were then identified for each
category or subcategory. This included an analysis of all
constituents of waste waters which may be expected in coal
mining or preparation plant waste water.
Each of these constituents found to be present was initially
evaluated against maximum concentrations recommended for
agriculture and livestock, public water supply, and aquatic
life and wildlife. Based on this evaluation constituents
which should be subject to effluent limitations and
standards of performance were identified.
Raw waste characterization was based on a detailed analysis
of samples collected during this study and historical
effluent quality data supplied by the coal industry and
Federal and State regulatory agencies.
Based on a critical review of the waste water
characteristics of the initial industry subcategories, it
was determined that there are generally two types of
untreated waste water for the mining segment of the industry
- alkaline, and acid or ferruginous - determined largely by
regional and local geologic conditions and not by mine size
or type of mine. Water quality within a particular class
(acid or ferruginous/alkaline) is reasonably uniform, and
the class of raw mine drainage determines the treatment
technology required. For the most part, the quality of
discharge effluent from acid mine drainage treatment plants
did not exceed the standards initially established for
reference. The quality of untreated alkaline mine drainage
was found to be commonly superior to effluent quality from
acid mine drainage treatment plants.
11
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It was therefore determined that the initial industry
subcategorization was not warranted and categorization was
based on SIC Code and the two classes of raw mine drainage.
It was also determined after review of coal preparation
plant visits and review of information supplied by the
industry that the existing practice and standard of the
industry was closed water circuits in the wet cleaning of
coal in coal preparation plants. This practice obtains no
discharge of pollutants for the actual cleaning of coal.
Waste water from coal preparation plant yards, coal stock
piles, and refuse disposal areas was either treated in the
same treatment facility as the mine drainage, or was treated
in a separate facility using similar techniques and methods
as used for the mine drainage from the mine served by the
preparation plant.
It was therefore determined that the mining services
category (coal preparation plants) should be subcategorized
as to the actual coal cleaning process itself (coal
preparation) and ancillary areas (coal stock piles, refuse
disposal areas, and coal preparation plant yards).
The full range of control and treatment technologies util-
ized within the major SIC industry categories was
identified. The problems, limitations and reliability of
each treatment and control technology and the required time,
cost, and energy requirements of implementing each
technology were also identified. In addition, this report
addresses all nonwater quality environmental effects of
application of such technologies upon other pollution
problems, including air, solid waste, noise and radiation.
All data was then evaluated to determine what levels of
treatment constituted "best practicable control technology
currently available," "best available technology
economically achievable,11 and "best demonstrated control
technology, processes, operating methods, or other
alternatives." Several factors were considered in
identifying such technologies. These included the
application costs of the various technologies in relation to
the effluent reduction benefits to be achieved through such
application, engineering aspects of the application of
various types of control techniques or process changes, and
nonwater quality environmental impact.
The data and effluent limitation guideline recommendations
presented in this report were developed based upon an
exhaustive review and evaluation of raw waste water and
12
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treated effluent sample data, available literature, and
visits to more than two hundred individual mine sites or
coal preparation facilities in twenty-two coal producing
states. The recommended effluent limitation guidelines
represent an analysis of these facilities, and a detailed
analysis of seven selected AMD treatment facilities and six
surface mine settling basins for 90 consecutive days to
verify historical data.
DESCRIPTION OF AMERICAN COAL FIELDS
The process of coal formation entails the accumulation and
compaction of organic materials beneath layers of sediments.
Such materials can accumulate in either fresh water or
marine environments, particularly where water levels are
subject to fluctuation and subsequent sediment influx. The
degree of compaction plays an extremely important role in
the classification of coals by rank. Coals are classified
according to relative percentages of fixed carbon, moisture
and volatile matter. Depending on the specific classifica-
tion system, this categorization can be general or extremely
detailed. Four general categories are discussed.
Minimal compaction of accumulated organic materials results
in formation of peat, which is not considered to be a type
of coal. The first major stage of compaction of peat
produces lignite, the lowest coal rank. The following
average characteristics are typical of lignite: 1) 30 per-
cent fixed carbon; 2) 25 percent volatiles; 3) US percent
moisture; and H) 6500 BTUs.
Compaction of lignite produces a higher rank of coal (sub-
bituminous) , which is still considered to be low quality.
Average characteristics of subbituminous coal are: 1) 12
percent fixed carbon; 2) 34 percent volatile matter; 3) 23
percent moisture content; and 4) 9700 BTUs.
Bituminous coal is produced by the continued increase of
pressure and compaction on the organic materials. Bitum-
inous coal as described here encompasses a large majority of
all coal mined today. Characteristics of bituminous coal
vary widely, and this rank can consequently be extensively
subcategorized. The range of general characteristics for
bituminous coal are: 1) 47 to 85 percent fixed carbon; 2)
22 to 41 percent volatiles; 3) 3 to 12 percent moisture;
and 4) 9,700 to 15,000 BTUs.
The highest coal rank - anthracite, requires extreme amounts
of heat and compaction for formation. The extremes required
seldom occur in nature and, as a result, anthracite coal is
13
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not common. Locally or regionally-confined areas of intense
folding or igneous intrusion, where they occur in coal-
bearing strata, may result in the development of anthracite
coal. General characteristics of anthracite coal follow: 1)
greater than 85 percent fixed carbon; 2) less than 3
percent moisture; 3) less than 12 percent volatile matter;
and 4) 12,000 to 15,000 BTUs.
Sulfur content is another important constituent of coal,
although it fluctuates greatly and cannot be related to coal
rank. The fluctuations in sulfur content are attributable
to variations in environmental conditions at the time of
deposition, accumulation and initial compaction of the
organic material. Sulfur content is discussed in greater
detail in the description of each coal producing region.
Coal rank, geologic occurrence, estimated reserves, general
mining procedures and economic conditions for the various
American coal-producing regions and provinces are discussed
in detail in the following section. Figure 1 illustrates
the location of major coal deposits in the United States.
Anthracite Coal
Although not a major fuel source for today's energy produc-
tion, anthracite coal has been historically significant in
the economic and industrial growth of the United States.
The United States is completely self-sufficient in
anthracite, with nearly all coal reserves and production
centered in Northeastern Pennsylvania (see Figure 2). The
coal lies within four individual fields - the northern,
eastern-middle, western-middle, and southern - located in
the Valley and Ridge Province of the Appalachian Highlands.
These coal fields cover a total of 1240 square kilometers
(^80 square miles) and each consists of one or more small,
U-shaped basins trending northeast-southwest between
adjacent ridges.
The basins or synclines are structural in nature, resulting
from downfolding of the rock units and coal seams. The
extent or degree of this downfolding is directly related to
the depths below the surface at which the coal seams lie -
as deep as 1800 meters (6000 ft) in the southern field where
folds are extremely tight.
The northern coal field encompasses the Scranton and Wilkes-
Barre region and underlies Lackawanna and Wyoming Valleys.
Coal reserves occur in a curved, canoe-shaped syncline with
a flat bottom and steep sides outcropping along the mountain
ridges. There are 18 workable seams lying at depths up to
H
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640 meters (2,100 ft), and the bulk of this field's reserves
can only be recovered by underground mining techniques. The
northern field has been extensively mined with
interconnecting workings that are largely inundated today.
As a result, the threat of massive water handling problems
due to seepage or flow from adjacent abandoned mines
prohibits economic extraction by deep mining of any of this
field's reserves. All current production in this field is
from bank recovery and strip mining operations, which do not
have prohibitively high pumping and mine drainage treatment
costs.
The eastern-middle field is centered around the Hazleton
area and consists of numerous long, narrow, east-west
trending coal basins. Mined portions of this field
generally lie above drainage along mountain ridges and are
gravity drained by specially driven tunnels. Total
stratigraphic thickness of the coal bearing formation in
this field is approximately 610 meters (2000 ft). The major
coal seam. Mammoth, ranges in thickness from 9 to 15 meters
(30 to 50 ft) and is one of Pennsylvania's most economically
important anthracite seams.
The western-middle anthracite field encompasses the Mahanoy-
Shamokin region and contains the same major seams found in
the eastern-middle field. All coal seams in the western-
middle field are contained stratigraphically within 760
meters (2,500 ft) of rock. Seams are flat-lying in some
areas and steeply pitching in others. Coal seams in the
Shenandoah and Mahanoy basins, including the Mammoth, are
folded over upon themselves, doubling the thickness of
mineable coal and locally achieving thicknesses of 60 meters
(200 ft). Coal basins in this field are almost totally
beneath natural drainage channels. Consequently, the
abandoned mines are inundated and mine pool overflows
account for most of the mine drainage pollution.
The southern field is the largest of the four coal fields
with an area of 520 square kilometers (200 square miles).
This field is extremely long, extending from the Lehigh
River valley westward almost to the Susquehanna River. The
26 workable coal seams in the southern field lie within a
670 meter (2200 ft) rock section. Coal seams dip very
steeply to depths of nearly 1800 meters (6000 ft)* Deep
mine workings in the southern field occupy positions both
above and below natural drainage. Consequently, mine drain-
age emanates from both mine pool overflows and drainage
tunnels.
15
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en
LEGEND
COAl DEPOSITS
SCATTERED COAL DIPOSITS
Adapted from illustration
in KEYSTONE COAL COAL DfPOSITS IN THI UNITED STATES
INDUSTRY MANUAUI974) tWAL W*rW»ll» IN Ifll UfMMtU dIAICd
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LEGEND
Anthracite
Lignite
Scattered
Lignite
ANTHRACITE a LIGNITE COAL DEPOSITS
Figure 2
LEGEND
• Bituminous
Subbltumlnwt
BITUMINOUS ft SUBBITUMINOUS COAL DEPOSITS
Figure 3
Mooted from illustration
fn KEYSTONE COAL
INDUSTRY MANIML{!974)
17
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Coal mining operations were present in nearly all of the
major anthracite fields by the early 1800fs. The use of
shaft mining for extraction of deep-lying coal was first
employed in these anthracite fields, and by 1870, total
annual anthracite production by deep mine methods alone was
about 13 million kkg (14 million tons). By the turn of the
century, there was a four-fold increase in total production,
still primarily by deep mine methods. World War I saw total
annual production reach a high of 91 million kkg (100
million tons), with a rapid post-war decline until about
1930. Anthracite production then remained stable at 50
million kkg (55 million tons) annually until 1948. During
this time strip mining gained importance, and production
from surface mines reached a high of nearly 10 million kkg
(11 million tons) in 1944.
Both surface and deep mine production of anthracite coal
have steadily decreased since the 1940's, although produc-
tion per square mile of coal field remains at least three
times greater than that for bituminous mining. The Pennsyl-
vania Department of Environmental Resources reported a total
anthracite production of 8,4 million kkg (9.25 million tons)
for 1970, and an annual production decline of about 10
percent annually in subsequent years. In 1973, anthracite
production was estimated at 5.8 million kkg (6.U million
tons) from 37 surface and underground mines and 10 secondary
recovery operations. At that time, underground, surface and
bank, mining accounted for approximately 0.6, 3.1 and 2.1
million kkg (0.7, 3.4 and 2.3 million tons), respectively.
Preliminary production figures for 1974 show, however, that
despite the energy crisis and increasing demand for fossil
fuels, anthracite production continues to decline. These
figures show an increase of 6.9 percent in bituminous coal
production and a decrease of 14.8 percent in anthracite coal
production. Consumer demand for anthracite from public
utilities and the iron and steel industry is limited, rela-
tive to the bituminous industry. As a result of these
factors, anthracite production is not expected to increase
greatly in the near future. In addition, production
increases are limited by labor shortages, lack of investment
incentive, high mining costs, lack of easily mineable coal
and environmental considerations. Although a great number
of problems affect the anthracite mining industry, the
increased demand for cleaner burning fuels could revitalize
the industry.
Total estimated coal reserves as of January, 1970, for the
four anthracite fields, were about 15 billion kkg (14
billion tons). Recoverable anthracite reserves, those seams
18
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oyer 0,6 meters (2 ft) thick, were estimated at 7 billion
kkg (8 billion tons). This figure indicates that 23 percent
of Pennsylvania's total recoverable coal reserves lie within
3 percent of its coal land.
Bituminous Coal, Subbituminous Coal and Lignite
Bituminous coal has been the major source of the Nation's
energy for the past three centuries. Production and
utilization of this resource has always been vitally linked
to the economic and industrial growth of the nation and, as
a result, trends in soft coal production have closely par-
alleled trends in nationwide industrial activity.
Bituminous coal, until recent years, was the only soft coal
product that was mined on a major scale. Its production has
peaked during each major war in the last century - World War
I, World War II, and the Korean Conflict - with an all-time
high of 572 million kkg (630 million tons) in 1947.
Production has also generally declined following each of
those periods, recovering only gradually. Since 1947
bituminous production has climbed at a fairly steady rate,
but has remained below 544 million kkg (600 million tons)
annually, except for one year.
The slow recovery of the coal industry to World War II pro-
duction levels has been in part caused by rapid, extensive
changes in consumer utilization of coal between 1947 and the
mid 1960's. During this period, the railroads converted
from coal-fired to diesel locomotives and much of the domes-
tic heating market converted from coal to oil or gas. These
demand declines were partially offset, however, by steadily
increasing use of coal in electrical generating plants.
Demand for low sulfur coal has increased substantially with
increasing concerns for cleaner stack emissions from gener-
ating stations. Low sulfur subbituminous and lignite coal
production is rapidly expanding to meet these needs.
Although these materials have lower heating capabilities
than higher grade bituminous, large deposits of low sulfur
material can be mined and sold to distant markets at costs
competitive with higher grade low sulfur bituminous coal,
which is much less common. Since deposits in several of the
major producing areas contain bituminous coal, subbituminous
coal, and lignite, all are "discussed together in the
following description of the Nation's major coal producing
regions.
Appalachian Basin. The Appalachian or Main Bituminous Coal
Basin is the easternmost, and currently most important, coal
producing region in the United States. The basin extends
from North-central Pennsylvania through portions of Ohio,
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Maryland, West Virginia, Virginia, Eastern Kentucky,
Tennessee, and Northern Alabama. This bituminous coal
producing region consists of a major, elongated depositional
basin containing a series of local, parallel, northeast
southwest trending synclinal basins, occasionally offset by
faulting.
The southern two thirds of the basin lies higher and has
been more severely eroded than the northern section. As a
result, many of the younger, stratigraphically higher seams
were eroded away, and only the older, deeper coal remains.
The younger, uneroded seams are generally limited to the
north-central portion of the basin, lying in West Virginia
and small adjacent portions of surrounding states. These
younger seams are thicker and of above-average quality.
The thickest strata in the basin lie along its eastern edge,
while the percentage of limestone and calcareous overburden
material increases to the west and south. These trends are
directly related to the depositional history of the strata
in the basin. The exposed land surface, which was the
source of sediments and coal-producing organic material, lay
to the east of the inland sea in which the materials were
deposited; and the deeper, marine portions of that sea were
located to the south and west. These trends are also
closely related to the pollution production potentials of
the coal strata. Many of the coal seams in the basin are
high sulfur and constantly produce acid during and after
mining. The limestone and calcareous units, where they are
present, have the ability to neutralize a substantial
portion of the acid produced. As a result, there is
generally a less serious acid mine drainage pollution
problem in western and southern portions of the basin.
Broad regional variations within, the basin have been an
important factor in determining trends of coal extraction
and resultant mine drainage patterns. Most major coal for-
mations outcrop, at least intermittently, around the rim of
the basin and lie at great depth at its center. Mining was
initiated along coal outcrops, particularly in thicker seams
in the northern portion of the basin - the Pennsylvania,
West Virginia, Ohio region. Here, surface mining has been
an extremely important extraction technique, since seams are
thick and relatively shallow. Farther south in the basin,
coal seams generally follow the basin's dip and lie at
greater depths, necessitating slope or drift mining to
maximize coal extraction. The bulk of Appalachian Basin
coal resources lie at depth in or near its center. As a
result, many newly opened or planned mines are being
designed with shaft entrances to reach deeper seams.
20
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The number of coal seams present in any single portion of
the Main Bituminous Basin is determined by local
depositional, structural and erosional conditions and, as a
result, is highly variable. Much of the basin has a large
number of seams, but many of those are local, discontinuous,
or too thin to mine. There are generally about 5 to 10
commercially mineable seams in any portion of the basin.
For example. Southeastern Ohio has over 50 identified coal
seams, but only about 11 of those are commercially mineable.
Coal quality also varies considerably according to the
original depositional environment. Quality of a single seam
can change quite drastically between geographic areas, and
different coal seams may be even more dissimilar. Sulfur
content of Appalachian coals ranges from 0.2% to 10%, and
all other important parameters have equally large ranges.
One of the most important and valuable coal deposits in the
Nation is the Pittsburgh seam, which underlies approximately
15,500 square kilometers (6000 square miles) in the north-
central portion of the Main Bituminous Basin. This coal is
characterized by a consistent average thickness of 2 meters
(6 ft) and high quality. It was extremely important during
the development of the early American steel industry.
Total coal reserves in the Appalachian Basin have been
estimated at 238 billion kkg (262 billion tons), most of
which is bituminous coal. This reserve figure is second
only to that of the Western Region - the Northern Great
Plains and Rocky Mountain Provinces - where vast untapped
lignite deposits in North Dakota increase the total reserves
to 787 billion kkg (868 billion tons).
Since this basin has been the primary source of American
bituminous coal for many years, trends in national coal
production have been those evidenced in Appalachia. Produc-
tion declined following the Korean War and has slowly and
steadily climbed since then. Recently passed environmental
restrictions and more strictly enforced safety laws have
significantly increased production costs, and, along with
labor disputes, have slightly depressed production in the
past few years. Bituminous coal production in this region
far surpassed that from any other coal-producing region, but
still decreased from 351 to 3*0 million kkg (387 to 375
million tons) between 1972 and 1973.
Interior Region. The Interior Coal Region consists of two
major basins - the Eastern and western - that underlie all
or part of nine states. The coal seams in this province
contain relatively high percentages of sulfur, but acid mine
waters are not as common as in the Appalachian Basin.
21
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Limestones and other calcareous rock units overlying coal-
bearing strata produce naturally alkaline surface waters and
neutralize any acid formed around the pyritic coal. Thus
mine effluents are often of acceptable quality in many
respects.
The Eastern Interior Coal Basin is a single, large basin
which underlies flat or gently rolling farmlands in
Illinois, Western Indiana, and Western Kentucky. Rock units
are relatively flat-lying throughout much of the basin, but
are found along the Ohio River in several overturned,
severely faulted folds. The basin locally contains as many
as 35 different bituminous seams, but only about eight high
volatile, high sulfur seams are major coal producers. BTU
content of the coals generally increases to the Southeast,
but ash and sulfur are unsystematically variable throughout
this field. Many of the economically important seams here
are shallow, and a substantial portion of this basin's coal
production is from large area-type surface mines utilizing
high capacity stripping equipment.
The Western Interior Coal Basin is substantially larger than
the eastern, extending from North-central Iowa southward
through portions of Nebraska, Missouri, Kansas, Oklahoma and
Arkansas. Coal seams in this basin are predominantly
bituminous with high sulfur, moisture, and ash content, and
have been correlated with seams found in the Eastern
Interior Basin. In addition to these bituminous seams,
there is also a small pocket of anthracite coal found in
Arkansas.
Characteristics of coal and overburden material in the
Western Basin show significant geographical variation. Coal
seams in Iowa are generally thin, lenticular and
discontinuous, andr as a result, mining operations are small
and mobile. Much of the northern portion of the basin is
overlain by glacial drift, which locally reaches depths of
150 meters (500 ft). Farther south, in Kansas, coals are
flat-lying and persistent with little faulting, but are
often too deeply buried to economically mine. The number of
seams identified in this portion of the basin exceeds 50,
but only seven are economically important. Overburden
thicknesses decrease eastward in the basin, and much of the
coal produced in Missouri can be surface mined. Area mining
techniques and large strip mining equipment make the mines
in this region highly productive. The interior Region has
been actively mined for many years and, as a result,
production trends have been closely aligned with those
observed in the Main Bituminous Basin. The conflicting
needs of recently passed clean air requirements and the
22
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energy crisis have caused coal production to fluctuate in
recent years, with a net production decline in this
province. Production totaled 140 million kkg (154 million
tons) in 1972 and dropped to 134 million kkg (148 million
tons) in 1973. Western Interior operations, which are
predominantly surface mines, showed an increase from 8.4 to
8.6 million kkg (9.25 to 9.5 million tons) during that
period. Production from the Eastern Interior Basin, however
declined from 132 to 126 million kkg (145 to 139 million
tons) .
The Interior Province contains an estimated 238 billion kkg
(262 billion tons) of coal reserves, and will certainly be
an extremely important factor in future coal production. As
energy and fossil fuel demands continue to increase,
production is expected to show a corresponding increase.
Western Region. The Western Region of the American coal
field consists of three coal provinces - Northern Great
Plains, Rocky Mountain, and pacific Coast - underlying eight
western states. These provinces are discussed in detail
below.
The Northern Great Plains Province consists of a vast
expanse of lignite and subbituminous coal deposits extending
into portions of Montana, Wyoming and North Dakota. This
coal province contains by far the largest coal reserve in
the Nation. Strata are generally flat-lying, with steepened
dips only along mountain flanks. The lignite fields are
defined or subdivided according to type of overburden
material above the mineral deposits - glacial drift in the
north and poorly consolidated, fine-grained, nonglacial
materials farther south. Due to the relatively recent
deposition of these lignite and subbituminous beds and the
lack of subsequent tectonic disturbance (folding or
faulting), the rank of Northern Great Plains Province coals
increases with depth of burial, which is in turn determined
by age of the deposits. Sulfur contents are one percent or
less and ash values are correspondingly low.
The Montana and Wyoming portions of this province contain
more subbituminous coal than lignite. Seam thicknesses
average 6.1 meters (20 ft), occasionally exceeding 30 meters
{100 ft)f and many of the deposits have unconsolidated
overburden. Surface mining is therefore relatively
inexpensive. The low rank and heating capabilities of the
coal or lignite are effectively countered by the low costs
at which that coal can be produced. Nearly all lignite
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currently produced is used for electrical generation, but
future intended uses for this material include gasification.
The Rocky Mountain Coal Province consists of a large number
of relatively small coal basins underlying portions of
Arizona, New Mexico, Colorado, Utah, Wyoming and Montana.
Coals in the northern and central portions of this province
occur in broad, asymetric, synclinal folds lying between or
paralleling various ranges of the Rocky Mountains. The coal
seams here are relatively flat-lying and deep in central
portions of the province, with steeper dips along basin
flanks. In several instances, coal deposits have been
warped upward by the regional tectonics that have formed the
mountains. As a result, many of the seams in the central
portion, particularly in Colorado and Utah, have steep dips,
severely limiting the amount of strippable coal.
Many of the seams in the southern portion of the province
are not persistent, extending only eight to
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mines, is the 1969 Federal Coal Mine Health and Safety Act.
In 1969 the average kkg per man day for deep coal mines was
14.7 kkg/man (15.6 tons/man). In 1973 this dropped to 10.2
kkg/man (11.2 tons/man) with a corresponding increase in
production cost. A marked increase in capital costs for
equipment and cost of materials to meet the 1969 Act has
also been experienced. These increased costs resulted in
mine closures which are continuing even with the increased
realization per ton of coal, and have discouraged the
opening of small independent mines which can not absorb the
increased costs. Since World War II the Nation's ' 50 top-
producing companies have increased their share of national
coal production from 42 percent to 69 percent. In 1972 the
top 15 companies produced 51* of the bituminous tonnage. In
1972, 80 percent of all underground coal production was from
mines with annual tonnages exceeding 181,400 KKG (200,000
tons). In 1973, 95 percent of total surface mined coal was
from mines producing more than 90,700 KKG (100,000 tons)
annually, and 70 percent was from mines producing over
181,400 KKG (200,000 tons) annually. This trend will
apparently continue in the future/ as small mining companies
are gradually forced to close due to more stringent environ-
mental and safety restrictions.
Coal is recognized as a major source of energy to meet the
nation's increasing demand for energy.
A recent study by the National Academy of Engineering (NAE)
concludes that, if the coal industry is to double production
by 1985 to meet increased energy demands, it must:
1. Develop 140 new 1,814,000 kkg/yr. (2,000,000-ton-per-
year) underground mines in the eastern states.
2. Open 30 new 1,614,000 kkg/yr. (2,000,000-ton-per-year)
surface mines in the eastern states and 100 new 4,535,000
kkg/yr. (5,000,000-ton-per-year) mines in the western
states.
3. Recruit and train 80,000 new coal miners in the eastern
states and 45,000 coal miners in the western states.
U. Manufacture 140 new 25.2 cu m (100-cubic-yard) shovels
and draglines.
5. Build 2,400 new continuous mining machines.
Also of interest are the NAE study's projections for
expansion in the transportation area to haul a doubled coal
output by 1985. They would entail the following:
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1. Construction of 60 new 1,81«,000 kkg/yr. (2f000,000-ton-
per-year) eastern rail-barge systems of 161 km to 805 km
(100 to 500 miles) each.
2. Construction of 70 new 2,721,000 kkg/yr (3,000,000-ton-
per-year) western rail-barge systems of 1609 km to 1931 km
(1,000 to 1,200 miles) each.
3. Building of four new 22,675,000 kkg/yr (25,000,000-ton-
per-year) slurry pipelines of 1609 km (1,000 milesy each.
1. Installation of two new 70,000,000 cum (2,500,000,000-
cubic-feet-per-day) gas pipe lines of 1609 km (1,000 miles)
each to transport synthetic gas from coal.
5. Manufacture of 8,000 new railroad locomotives and
150,000 new gondola and hopper cars.
This last point is particularly important because the poor
financial condition of the country's railroads will limit
their ability to provide sufficient rolling stock (coal
cars) to move the needed quantity of coal from the mines to
the point of consumption.
DESCRIPTIONS OF FACETS OF THE COAL INDUSTRY
As the major SIC categories imply, the coal Industry can be
divided into two segments - coal mining and coal mining
services (coal cleaning or preparation). Each of these
categories is discussed in detail in the following section.
COAL MINING
Mining Techniques
Coal mines are classified according to the methods utilized
to extract coal. Methods selected to mine a coal seam in
any specific area depend on a number of physical and
economic factors: 1) thickness, continuity and quality of
the coal seam; 2) depth of coal; 3) roof rock and
overburden conditions; 4) local hydrologic conditions as
they relate to water handling requirements; 5) topography
and climate; 6) coal market economics; 7) availability and
suitability of equipment; 8) health and safety
considerations; and 9) any environmental restrictions which
could affect the mine.
Surface or strip mining is employed where the coal is close
enough to the land surface to enable the overburden (the
rock material above the coal) to be removed and later
28
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attributable to the low ash and sulfur contents and the ease
with which much of the coal can be rained. With increased
demand for low sulfur power generating coal to decrease
stack emissions, the subbituminous and lignite mining
portions of the coal industry have mushroomed in recent
years. Between 1972 and 1973 the following production
increases were noted for the Western Region: 1) Pacific
Coast Province - 2.4 to 3.4 million kkg (2.6 to 3.7 Billion
tons), 2} Rocky Mountain Province 29.1 to 33.7 million kkg
(32.4 to 37.2 million tons), and 3) Northern Great Plains
Province - 42.8 to 49.5 million kkg (47.2 to 5*.6 million
tons). For the sane basic reasons, the Western Region is
also expected to show the greatest future production
increases. The most comprehensive coal exploration and mine
development programs are currently in-, progress here, and
this region contains an extremely large reserve - an
estimated 793 billion kfcg (874 billion tone). These
characteristics combine to make the Western Region a
potential future leader in American coal production.
Future production Tr grids . There are a number of factors
that will be extremely important in determining future
production trends of the coal industry. The energy crisis
has produced a steady, dramatic increase in demand for coal,
which in turn provides a strong incentive to increase
production. The value of a ton of coal has significantly
increased to the point where previously uneconomic or
marginal coal deposits can now be profitably extracted and
marketed. However, increased demands for coal and avail-
ability of economically mineable coal have not inspired
increased production as they should have. These factors are
tempered by several other important considerations which
have actually reduced production slightly.
Environmental aspects of coal utilization iww* aweefttly
become critical in de-termini ng current mining trends, and
will continue to gain importance in th« future. Stringent
clean air restrictions have been imposed on coal-burning
electric generating plants, which used 90 percent of all
coal produced in 1973. Most of these plants are located in
the eastern United states, near major population and
industrial centers, an& the coal they burn is almost
exclusively high-sulfur Appalachian Basin bituminous coal.
Equipment has been developed to reduce the undesirable
emissions caused by burning high-sulfur coal, but the
technology has not yet been fully perfected and ecpiipm^Tit is
costly. At present, a financially feasible alternative to
installation of this emission equipment is Btilizatioa of
low-sulfur «4tttffi3l £oal or lignite. This 00*1 ill -Q£
25
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rank and commonly has a lower BTD value than eastern
bituminous coal, meaning that more lower rank material must
be burned to obtain the same amount of heat. These low rank
bituminous coals and lignite deposits are found in the
western coal fields, where seams are thicker, overburden is
thinner, and water problems are minimal. As a result, the
coal can be more easily mined, shipped east, and sold at
prices that are competitive with those for Appalachian high-
sulfur coal. Western coal fields have been experiencing a
rapid mining expansion, which should continue for some
years. As these western fields achieve full production,
annual tonnages for national surface mining of coal should
increase significantly.
One of the major deterrents to expansion of the coal
industry is availability of transport for the coal to the
consumer. The present transportation system, particulary
railroad systems, are operating at capacity. Alternatives
suggested for railroad transportation include slurry pipe
lines, mine mouth power plants, and mine mouth gasification
and liquification plants.
The immediate demand for coal is not expected to greatly
increase the percentage of coal produced from underground
mines. Many active deep mines are already operating at
maximum potential, with no practical way to increase
production. The reserves of coal that can be extracted
utilizing current underground mining technology at
competitive costs is relatively small when compared to the
total deep mine reserve. Large scale percent increases in
underground mine production can only occur if the technology
is perfected to enable economic, safe extraction of deeper
lying coal seams which comprise the bulk of this country's
reserves. If these technological breakthroughs occur,
underground mine production can be expected to increase
substantially not only on an annual basis, but also on the
percent extracted by underground methods.
Economic considerations have also had an important role in
establishing a trend toward the prominence of larger mines
and mining companies. Environmental restrictions and
regulations on surface mines have increased production and
capital costs substantially. It is frequently impossible
for smaller mining operations to comply. As a result, small
operations are becoming scarce, because their owners are
forced by economic conditions to close. Larger companies
are more capable of absorbing these production costs.
A major effect on the productivity of individual deep mines,
which has reflected in the number of mines and size of
26
-------
replaced or regraded while still realizing a profit from the
coal sale. Extraction of coal with large augers, which can
be accomplished without removing overburden material, is
also occasionally utilized at surface mines. Where the coal
is too deep to permit profitable strip mining, underground
mining techniques are utilized. These major methods of
extracting coal are discussed in detail in the following
pages.
It should be noted that regardless of the method of mining,
water use is generally limited to dust suppression, and in
the United states is not used as an integral part of any
major'mining technique. Water removal is required as it is
a nuisance and hinderance to mining. As such, mine
dewatering and handling is a required part of the mining
plan at most coal mines, and, as such, mine drainage is
considered a waste water for the coal production segment of
the industry.
tlnderxiround Mining. Underground mines are developed by
driving entryways into a coal seam and are classified
according to the manner in which the seam is entered. Drift
mines enter the coal at an outcrop, the point at which the
coal seam is exposed on the land surface. Drifts are the
cheapest method of access to underground mines, where
conditions are suited, and provide horizontal or nearly
horizontal access to the mine workings. Slope mines are
found where the coal is at an intermediate depth or where
the coal outcrop condition is unsatisfactory or unsafe for
drift entry. Slope mines employ an inclined slope entry
driven to the coal from the land surface above. Slope entry
use allows the coal to be entered from above while permit-
ting continuous haulage of coal from the workings up the
slope , to the surface. Shaft mines are utilized where the
coal lies too far below the surface to outcrop. The shaft
itself is a vertical entry driven tos a coal seam from the
land surface above. Access to the workings and mined coal
must then be transported via elevators in the mine's shaft
or shafts.
The method of entry employed to gain access to a coal seam
can be extremely important in development of an underground
mine. Drift entries must be driven from the coal outcrop,
regardless of where the remaining extractable coal lies.
Slope entry locations are also restricted with relation to
the remainder of a proposed mine by the thickness of
overburden, A shaft entry can be located to facilitate
entry and coal haulage while minimizing any anticipated
problems. However, the cost of a shaft is directly related
to the depth of the shaft.
29
-------
The mining techniques employed in the mines themselves are
not dependent on the type of entryway in use, and are fairly
uniform in all underground mines. Most American coal mines
utilize room and pillar extraction. Main tunnels, or
headings, are first driven from points of entry. From these
main headings, secondary headings are driven
perpendicularly. configuration of crossheadings, or
crosscuts, must be carefully planned to permit adequate
ventilation, support of headings, drainage of the workings,
and to facilitate coal haulage, Blocks of coal are then
extracted in some systematic pattern along both sides of the
headings, and pillars of intact coal are left between the
mined out rooms to support the mine roof and prevent surface
subsidence above the workings, configurations of rooms and
pillars are designed to consider roof conditions, equipment
utilized, depth of the seam and other physical factors.
Room and pillar mining permits extraction of 40 to 60
percent of the coal in the mine, with the remainder left in
the form of pillars.
Room and pillar mining is also effectively employed in
extraction of very steeply dipping anthracite coal seams in
northeastern Pennsylvania. In these mines, terminology
differs but the technique is quite similar. The primary
change required for steep dip mining is in the type of
haulage employed, particularly from the coal face. Suffi-
ciently steep workings are able to rely solely on gravity
for haulage from the face to some collection point. Where
other special haulage plans or equipment are required,
mining costs may increase significantly, .but the general
mining system is still adaptable for use under these
circumstances.
There are two predominant coal extraction procedures
currently employed in American underground bituminous coal
mines - conventional and continuous mining. Conventional
mining consists of a repeated series of steps used to
simultaneously advance a series of rooms. The procedure
rotates a set of mining equipment from one room to another
so that each piece of equipment in the set, or mine "unit™,
is always working somewhere. In this manner, no men or
equipment in the unit sit idle waiting for their step of the
procedure.
The sequence of events that lead to extraction of coal and
advancement of the room is: 1) undercutting or overcutting
the coal seam with a mechanized "cutter" as required to
permit expansion of the coal upon blasting while minimizing
damage to the roof rock; 2) horizontally drilling the coal
at predetermined intervals to enable placement of explosives
30
-------
and blasting; 3) breakage of the coal by either explosives
or high pressure air; 4) loading coal onto haulage vehicles
or conveyor belts; and 5) roof bolting or timbering to
support overburden material where the coal has been removed.
Conventional mining as described above is gradually being
replaced by continous mining equipment. A "continous miner"
is a single mechanized unit which breaks or cuts coal
directly from the coal face and loads it onto haulage
vehicles or belts. This eliminates equipment and operating
personnel.for cutting, drilling, and blasting. Secondary
coal haulage from a coal face can be accomplished by rubber
tired electric shuttle cars or by small conveyor systems.
Primary haulage from these secondary systems to mine portals
is generally accomplished by specially designed electric
rail equipment or by conveyor systems.
Initial development in an underground mine may leave as much
as 60 percent of the coal in pillars. Following development
of entries, it is often possible to safely remove some of
those pillars as the machinery retreats from an area of the
mine, when pillars are "pulled" coal recovery for the mine
significantly increases. However, resultant roof collapse
and fracturing can greatly increase overburden permeability,
facilitating mine water infiltration and subsequently
increasing mine drainage problems. This is particularly
true when operating under shallow cover or overburden.
Another deep mining technique, longwall mining, is
relatively new to the American mining industry, although it
is extensively used in Europe. An advantage of this
technique is that it permits increased recovery of coal.
Coal is extracted along a single "face" which is much longer
than those used in room and pillar mining. The longwall can
range from 30 to 200 meters (100 to 700 feet) in width and
up to 2,000 meters (6,600 feet) in length.
Longwall mining equipment consists of hydraulic roof
supports, traveling coal cutter, conveyors and power supply.
Parallel headings of variable length are driven into the
coal and a crossheading is driven between them at their
maximum length. Equipment is installed in this third
heading and working of the new face is initiated. Cutters
move along the face and the cut coal falls onto a chain
conveyor which parallels the face. Roof supports advance
with the longwall face, restricting the size of the working
area adjacent to the face, but permitting controlled roof
collapse as the longwall progresses. Longwall mining
-------
generally increases percent of recovery over room and pillar
methods.
Front this brief description, it. is obvious there is a wide
range of mine types and equipment that can fee utilized for
coal extraction. Equipment and techniques
employed at a particular mine are largely dependent on the
physical and economic conditions at that site. Since these
factor* are subject to wide local variations, each existing
or propoe*
-------
The sequence of operations, that occurs in a typical surface
mining operation is the mine site is cleared of trees and
brush, overburden is vertically drilled from the surface,
explosive charges - generally ammonium nitrate - are placed
and the overburden is blasted or "shot". This sufficiently
fractures the overburden material to permit its removal by
earth moving equipment such as draglines, shovels or
scrapers. Removal of this overburden generally takes the
greatest amount of time and frequently requires the largest
equipment. Specific sizes and types of equipment utilized
vary according to conditions at each mine, with bucket
capacities of the largest shovels and draglines currently
exceeding 150 cubic meters (200 cubic yards).
Following removal of the overburden material, coal is loaded
onto haulage trucks or conveyors for transport. Spoil
backfilling follows coal extraction, and can be done with
draglines, shovels, dozers, or scrapers depending on the
conditions of the material and the amount that must be
moved. The backfilled spoil is then regraded and seeded to
establish vegetative growth and minimize erosion.
There are two general categories of strip mines which are
defined largely by topography of the mined area - contour
and area. The sequence of strip mining operations described
above is utilized in both types of mines. Contour strip
mining (see Figure 4) is most common where coal deposits
occur in rolling or hilly country, and is widely employed in
Pennsylvania, West Virginia, Virginia, Maryland, Ohio^
Eastern Kentucky, Tennessee and Alabama. In contour
stripping, an initial cut is made along a hillside, at the
point where the coal outcrops, or is exposed at the land
surface. Successive cuts are made into the hill until it
becomes uneconomical to remove further overburden. In this
manner, the strip cuts follow the contour of the coal
outcrop around the hillside, generally resulting in a long,
sinuous band of strip mined land around an entire hill.
Contour strip mining results in a bench or shelf on the
hillside where the coal has been removed, bordered on the
inside by a highwall and on the outer, downslope side by the
piled spoil material. Prior to recent passage of strict
mining regulations, much of this spoil material remained on
the natural slope below the bench, creating a spoil outslope
much steeper than the natural land slope. Such
unconsolidated spoil banks can create severe erosion and
landslide problems.
The area strip mining technique , is used extensively in
relatively flat-lying lands of the Midwest and West, Area
stripping, as the name implies, affects large blocks of
33
-------
Bench
Bsflssftstf
. •'. ¥ -j^< H> •'<: .3^<".* ^ *>.'~i.(..-. '. ". *,.s ^. e TV 4.* . i
••• •^i/*-'/''va'A.'j')1 ,*i* 7"^V Mr* v" > «*.J'i"-"-,<-'*?"''*7',*H''**'i'<"^"<.*-''""*v
%»-,*.,.• '<««x»*»VLvrt'-.'<•" *;••'.•«;?-<,..v.'«v-i> '" ::*"•-.'.*- •
CONTOUR STRIPPING
Figure 4
-------
land, rather than the sinuous bands of contour stripping.
The first cut in an area mine is generally made to the
limits of the property to be mined. Coal is extracted from
this cut and mining proceeds in a series of cuts, parallel
to the first and adjacent to one another. Spoil from each
new cut is placed in an adjacent completed cut, from which
the coal has been removed. Thus the final cut in an area
mine is the only one with either an exposed highwall or open
cut, ridges. Until recently, the last cut was frequently
developed into a large lake. However, with stricter
reclamation laws, area mines must also be entirely regraded
to approximate original contour. Figure 5 illustrates the
sequence of operations in an area mine with concurrent
regrading.
Auger mining is most commonly associated with contour strip
mining, and is thus largely confined to eastern coal fields.
Augering is one of the least expensive methods of extracting
coal, but is limited to horizontal and shallowly dipping
seams where easily accessible outcrops or highwalls exist.
Large augers drill horizontally into a coal seam from the
outcrop or the base of the highwall, after the overburden
becomes too thick to remove economically. Auger heads range
from 41 to 213 centimeters {16 to 84 inches) in diameter and
can penetrate more than 60 meters (200 ft) into the coal.
Depending upon the thickness of the coal and spacing of the
holes, auger mining can recover 50 to 80% of the coal.
Generally overburden collapses into the empty holes.
COAL MINING SERVICES OR COAL PREPARATION
Coal cleaning has progressed from early hand picking
practices for removal of gross refuse material to present
technology capable of mechanically processing coal fines and
slimes, permitting greater recovery of selected
compositions. These technological advances were introduced
with mechanization of the mines and were stimulated by more
stringent market quality requirements and increased coal
production rates. Approximately
-------
CO
CFJ
iOHglnal Ground
! Surface 5^S^S=^
AREA MINING WITH SUCCESSIVE REPLACEMENT
Figure 5
Adapted from drawing in
STUDY OF STRIP AND
SURFACE MINING IN
APPALACHIA (1966)
-------
metallurgical coal. This is because the coke industry has
the most stringent standards of all major coal consuming
industries. Detailed preparation provides a uniform product
with reduced sulfur and ash content important to coke plant,
blast furnace, and foundry-cupola operations. Although
utility coal must have relatively uniform size, economic
benefits accrued from extensive cleaning have not been
sufficient to offset additional preparation costs. However,
more complete cleaning of utility coal may be required with
increased enforcement of sulfur dioxide emission limitations
for power generating plants. Responsibility for controlling
stack emissions will be placed on electric and mining
companies. Generating stations will eventually be required
to install scrubbers or similar equipment for sulfur removal
from gases, and the mining companies will be forced to
supply a cleaner, lower sulfur coal.
Coal Preparation Plants
Three general stages or extent of coal cleaning are
practiced within the coal mining industry. Coal preparation
plants are individually grouped in these stages according to
degree of cleaning and unit operations. Transportation of
raw coal from a mine site to a preparation plant, and
transportation of clean coal and refuse from the plant are
unit operations common to all stages of preparation. These
transport operations do not enhance coal quality or affect
the cleaning processes. Thus, coal and refuse
transportation procedures and environmental controls are not
delineated in the analysis of each stage of preparation.
Stage I:. Crushing and Sizing - Basic Cleaninf. This stage
of coal cleaning is basic and involves only crushing and
sizing. Preparation plants grouped in this stage always
perform primary crushing, and in many instances secondary
crushing is also employed to effect further size control.
The two major objectives in Stage 1 preparation are: 1) a
reduction of raw coal to uniform market sizes; and 2) seg-
regation of refuse material which usually appears as reject
from the first screening. Since these goals are
accomplished with removal of only large refuse material.
Stage 1 cleaning plants achieve maximum calorific recovery
(approximately 95 percent clean coal) but minimal
improvement in ash and sulfur contents.
Equipment used in this cleaning process is common to all
stages of preparation. A variety of comminution units are
employed, including single and double roll crushers, rotary
breakers, hammer mill and ring crushers, and pick breakers.
37
-------
Rotary breakers (Bradford breakers) serve a dual function by
breaking coal to a predetermined top size and removing
refuse and trap iron. Thus, this particular comminution
unit receives wide use throughout the coal industry.
Screens are usually employed in conjunction with crushers to
provide additional segregation or sizing of coal. Moving
and stationary screens are available to accomplish desired
sizing. The most common screens are punched plate and woven
wire vibrating screens.
Flow paths of coal and refuse within a typical Stage 1 prep-
aration plant are shown in Figure 6. This flow diagram
illustrates the location of standard and optional equipment
in an entire cleaning system.
A water circuit is not included in plant design because
Stage 1 preparation is usually a dry process. Lack of plant
process water limits water pollution potential to surface
runoff near the plant and from refuse disposal areas.
Stage 2:. Hydraulic Separation Standard Cleaning. Stage 2
coal preparation is a standard system that provides a clean
coal product usually for the utility coal market. This
process typically incorporates comminution and sizing to
about 8 to 10 centimeters (3 to H inches) top size, and
optional by-pass of minus 1 centimeter (3/8 inch) material.
Coal cleaning is usually accomplished by jigs using a
pulsating fluid flow inducing particle stratification via
alternate expansion and compaction of a bed of raw coal. A
density segregation is effected with dense impurities in
bottom layers and clean coal in upper layers of the particle
bed. A primary objective of Stage 2 preparation is removal
of liberated mineral matter by cleaning at high gravity.
This provides a uniform product with reduced ash and sulfur
content. Coal preparation plants employing this system
accrue a high calorific recovery with some inherent loss of
combustible material (80 percent clean coal recovery).
Fine coal is usually not cleaned and is directly blended
with coarse clean coal. However, Stage 2 preparation plants
can be modified to include a fine coal circuit for cleaning
minus 1 centimeter (3/8 inch) material. Cleaning of fine
coal involves either wet or dry processing and provides
additional quality control.
A very limited number of fine coal cleaning circuits utilize
air cleaning tables. A thermal dryer may be incorporated to
reduce moisture in advance of air cleaning because excessive
moisture can lower the efficiency of air cleaning processes.
38
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Deep or Surface
Mine Area
Trash
Removal
(optional)
Storage
bptioran
"V
Rotl Crusher
{optional additional \
v size control '
QJ
Barge
Unit Train
Consumer
Truck
STAGE I-COAL PREPARATION PLANT
Figure 6
39
-------
Most fine coal cleaning circuits employ shaking tables,
hydrocyclonesf or heavy media cyclones for cleaning fines,
and extreme fines are by-passed to refuse or blended with
coarse coal. Mechanical drying (centrifuge) is usually
required with wet cleaning of fine coal. Thermal drjf^rs are
vised for fine clean coal only when necessary.
Unit operations in a Stage 2 preparation plant are: Primary
crushing; sizing; gravity separation of coarse coal; dewa-
tering of clean coal and refuse; and removal of fines from
process waters. The following equipment is frequently
employed to perform individual unit operations: single or
double roll crushers and vibrating screens for comminution
and sizing; jigs for gravity separation; vibrating screens
for dewatering; and drag tanks and thickeners or settling
ponds to remove coal fines.
Material transfer and equipment locations for a Stage 2
preparation plant are shown in Figure 7. Since Stage 2 coal
preparation utilizes wet processing, degradation of process
water will undoubtedly occur. Suspended solids are the
greatest pollutant, and inclusion of a fine coal cleaning
circuit intensifies this problem. closed water circuits
with either thickeners or settling ponds to remove fines
will ameliorate most of the water pollution problems.
A majority of Stage 2 preparation plants surveyed during
•this study had closed water circuits. In addition, pH
control was occcasionally used to limit acid concentration.
This usually involves addition of lime to make-up water.
Stage _3: Dense Medium Separation - Complete Cleaning. Coal
preparation plants grouped in Stage 3 provide complete and
sophisticated coal cleaning. Most metallurgical coal is
subject to this detailed preparation, resulting in a
superior quality, uniform product having reduced ash and
sulfur to meet prescribed specifications. Sized raw coal is
cleaned in a Stage 3 preparation plant by immersing it in a
fluid acting at a density intermediately between clean coal
and reject. This produces a stratification of material
according to specific gravity. Magnetite is the most common
dense media employed for cleaning coal, although sand is
still occasionally used.
These processes are predicated on a size reduction to attain
the maximum liberation (freeing of particles) that can be
economically justified. The resultant increase of fine
particles requires additional processes to achieve maximum
coal recovery (approximately 70 percent), meet moisture
specification for tfce clean coal, and to close the water
40
-------
Raw Coal
Breaker
(optional)
Refuse
Disposal
Fine
Coal
Storage
Primary
Crusher
Air Tobies
T*
Refuse
Disposal
ShaKing Table,
H.M. Cyclone
or
Hydro-Cyclone
ewatennq
Screens
Clean
Coarse
Cool
Storage
Clean,
Dry,
Fine
Coal
Storage
Sieve Bin,
Classifier
or
Cyclone
To Refuse Disposal
Thickener
Settling Pond
LEGEND
* • •
- Route of Fine Coa I
Route of Fine Coal
of Refuse
•-Route of Fresh Make-up Wafer
• -Route of Dirty process Water
• -Route of Clean Process Water
1111111111%-Route of Coarse Coal
STAGE 2-COAL PREPARATION PLANT
Figure 7
41
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circuit. Major unit operations involved in the complexities
of stage 3 preparation are: comminutions sizing; gravity
separation; secondary separation; dewataring; heavy media
recovery; and water control.
Equipment used in Stage 3 preparation plants varies
according to product requirements and individual operator
preferences based on raw coal characteristics. Comminution
is primary crushing usually by a single roll crusher and
secondary crushing using a double roll crusher. Material
from the crushers is screened with topsize 3.8 to 1.9
centimeters (1 1/2 to 3/4 inches) going to coarse coal
cleaning and undersize to fine coal and slimes cleaning.
Coarse coal separation is generally accomplished with heavy
media vessels (1.35 - 1.05 gravities), and fine coal
separation by heavy media cyclones (1.32 - l.ftS gravities) .
Slimes cleaning usually involves hydrocyclones and froth
flotation cells.
Clean coarse coal and refuse from heavy media vessels are
dewatered on drain and rinse screens. Dewatering of the
fine coal and refuse from heavy media cyclones includes
sieve bends and centrifuges as well as drain and rinse
screens. Proper dewatering of slimes usually requires
filtering and thermal drying. Thermal dryers are also
occasionally employed to dewater fine coal from centrifuges.
Since magnetite is a common heavy media used for coal sepa-
ration, recovery and reuse of media is an economic
necessity. The last process in a Stage 3 cleaning plant is
removal of particulate matter from process waters by
thickeners (sometimes settling ponds) prior to recycling.
Figures 8, 9, and 10 depict a typical stage 3 coal prepara-
tion plant for coarse, fine, and coal slime recovery.
Most Stage 3 preparation plants have closed water circuits
using thickeners to maintain acceptable loads of suspended
solids in recycled water. Froth flotation commonly utilizes
pH control because both product quality and recovery can be
affected. Lime is often added to make-up water to maintain
a pH between 6.0 and 7.5. Treatment of small quantities of
make-up water is less costly than treatment of larger
quantities of water not recycled.
42
-------
Raw CoaI
• Trash
Removal
iinnuniinnnj
*
Secondary
Crusher
Primary
Crusher
Make-up
Water
Storage
|Medium Sump] 5
Heavy Medio Vessel
.__JL
FINl COAL
•(See Figure No.9)!
Drain-Rinse
Screens
*
, COAL SH ME
• PREPARATION
(See Figure No. I0)i
I— _ „ ^— _H.— __, _. ^^_. _ _ ^_
LEGEND
To
Refuse
Disposal
{Medium ThicKener] **
A
Magnetic Separator]
*+
Route of Fine Coal
Route of Coarse Coal
Route of Refuse
Route of Heavy Media Slurry
^-Optional Route-Smk-Roat+Media
»>- Route of Sink- Float+Media
» -Route of Magnetite
- Route of Dirty Process Water
- Route of Clean Process Wafer
- Route of Fr e sh Make -up Water
STAGE 3-COARSE COAL PREPARATION PLANT
Figure 6
43
-------
BS Rom Deslimtng Scr
(See Figure No. 8)
Make-up
Water
Storage
Heavy Media ,~
Cyclone «**
t
To Refuse
Disposal
»
^JMagnetic Separator!
To Desliming Screen
(See Figure No,8)
LEGEND
— — —*- Route of Sink- Float -t-Mtdta
»*«»»«>-Routeof Magnetite
^-Route of Dirty ProcetiWater
••-Route of Clean Process Wrier
Route of Fine Cool •
ii^-Opt'ionat Route of Fine Coal
• • • •
-------
(Hydro
'5£P*
i
i
i
|^--r \Sieve/ "1
1 MS/ |
^ ™^**- Route af Coal Slime
r
terp? t ,,,,,,, ,^
! .
r? ^ 1
Dfsposol
-------
-------
SECTION IV
INDUSTRY CATEGORIZATION
The development of effluent limitation guidelines can best
be realized by categorizing the industry into groups for
which separate effluent limitations and new source per-
formance standards should be developed. This categorization
should represent groups that have significantly different
water pollution potentials or treatment problems.
In order to accomplish this task, initial coal industry
categorization was based on four important characteristics:
1) rank of coal mined; 2) geographic location; 3) type of
mine; and U) size of mine. Categorization by rank of coal
mined was based upon the following previously established
Standard Industrial Classification (Sicy groups:
SIC 1111 Anthracite Mining
SIC 1112 Anthracite Mining Services
Sic 1211 Bituminous Coal and Lignite Mining
SIC 1213 Bituminous coal and Lignite Mining Services
Bituminous and lignite mining was further subcategorized by
geographic region, which was originally believed necessary,
because of anticipated variations in raw mine drainage.
These variations in mine discharges are determined by such
factors as climate and chemical characteristics of the coal
and overburden.
Anthracite, bituminous and lignite mining were
subcategorized by mine type and size. underground and
surface mining operations were differentiated because of the
obvious gross differences in mining techniques. These
differences could result in significant variations in raw
mine drainage. Mine size was also deemed important because
economic considerations, particularly capital and operating
costs of treatment facilities, could prohibit smaller
operations from complying with proposed effluent
limitations.
For the purpose of developing effluent limitation guidelines
the term coal mine means an active area of land, and all
property placed upon, under or above the surface of such
land, used in or resulting from the work of extracting coal
from its natural deposits by any means or method including
secondary recovery of coal from refuse or other storage
-------
piles derived from the mining, cleaning, or preparation of
coal.
A coal operation is considered as one mine if the pits are:
owned by the same company, supervised by the same
superintendent, and located in the same county.
The term mine drainage means any water drained, pumped or
siphoned from a coal mine.
The preliminary industry categorization resulted in the
following breakdown:
I. Anthracite Mining - Pennsylvania only
A. Surface Mines
Large - greater than 136,000 KKG
(150,000 tons) per year
2. Small - less than 136,000 KKG
(150,000 tons) per year
B. underground Mines
1. Large - greater than 136,000 KKG
(150,000 tons) per year
2. Small - less than 136,000 KKG
(150,000 tons) per year
II. Anthracite Mining Services (Preparation Plants)
III. Bituminous coal and Lignite Mining
A. Eastern and Interior Area - Pennsylvania, Ohio,
Maryland, Virginia, West Virginia, Kentucky,
Tennessee, Alabama, Illinois, Indiana, Iowa,
Missouri, Kansas, Oklahoma, Arkansas
1. Surface Mines
a. Large - greater than 136,000 KKG
(-150,000 tons) per year
b. small - less than 136,000 KKG
(150,000 tons) per year
2. Underground Mines
a. Large - greater than 136,000 KKG
(150,000 tons) per year
b. small - less than 136,000 KKG
(150,000 tons) per year
B. Western Area - Montana, North Dakota, South
Dakota, Wyoming, Utah, Colorado, Arizona, New
Mexico, Washington, Alaska.
1. Surface Mines
a. Large - greater than 136,000 KKG
(150,000 tons) per year
b. Small - less than 136,000 KKG
(150,000 tons) per year
48
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2. Underground Mines
a. Large - greater than 136,000 KKG
(150,000 tons) per year
b. Small - less than 136,000 KKG
(150,000 tons) per year
IV. Bituminous and Lignite Mining Services
(Preparation Plants)
One of the initial goals of this study was determination of
the validity of this categorization. The primary source of
data utilized for this evaluation was information obtained
during the study's sampling program and mine visits. This
information was supplemented with data obtained through
personal interviews, literature review, and historical
effluent quality data supplied by the coal industry and
regulatory agencies.
Based upon an exhaustive data review, the preliminary
industry categorization was substantially altered.
The data review revealed there are generally two distinct
classes of raw mine drainage - Acid or Ferruginous and
Alkaline - determined by regional and local geologic
conditions. Raw mine drainage is defined as acid or
ferruginous raw mine drainage if the untreated mine drainage
has either a pH of less than 6 or a total iron of more than
10 mg/liter. Raw mine drainage is defined as alkaline raw
mine drainage if the untreated raw mine drainage has a pH of
more than 6 and with a total iron of less than 10 mg/liter.
It was determined that rank of coal
(anthracite/bituminous/lignite), type of mine
(surface/underground), and mine size did not significantly
affect the categorization of mines by these two raw mine
drainage classes.
Categorization by rank of coal has been maintained, since it
is defined by the SIC classes that apply to the coal
industry. However, mine size and type were dropped from
consideration, and a revised industry categorization was
developed.
This revised industry categorization consisted of the Sic
classes and two large regions, determined by the
predominance of Acid or Ferruginous raw mine drainage.
Region I, states or areas characterized by Acid or
Ferruginous raw mine drainage is comprised of Maryland,
Pennsylvania, Ohio, and northern West Virginia. Isolated
mines or areas in Western Kentucky and along the Illinois-
49
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Indiana border also exhibit acid or ferruginous raw mine
drainage. Region II includes all the remaining coal
producing areas which exhibit predominantly Alkaline raw
mine drainage.
Statistical analysis of all raw mine drainage obtained
during the field program substantiated the revised
categorization based on the chemical characteristics of the
raw mine drainage. Based on this information, it was
determined there was no need for further industry
categorization of the coal mining segment of the industry
other than by raw mine drainage characteristics.
Mining services were evaluated as to the process waste water
from the coal cleaning process itself-coal preparation plant
waste water. Drainage, or waste water, from a preparation
plant's yards, coal storage areas, and refuse disposal areas
was evaluated separately as, coal preparation plant
ancillary area waste water.
REVISED INDUSTRY CATEGORIZATION
I Anthracite Mining, Bituminous Coal and
Lignite Mining
A. Acid or Ferruginous Raw Mine Drainage
B. Alkaline Raw Mine Drainage
II Anthracite Mining Services, Bituminous and
Lignite Mining Services
A. Coal Preparation Plant Waste Water
B. Coal Preparation Plant Ancillary Area waste Water
50
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SECTION V
WASTE CHARACTERIZATION
The nature and quantity of pollutants discharged in waste
water from surface and underground coal mining operations
,and coal preparation facilities varies significantly
throughout the United States. The waste water situation
evident in the mining segment of the coal industry is unlike
that encountered in most other industries. Usually, most
industries utilize water in the specific processes they
employ. This water frequently becomes contaminated during
the process and must be treated prior to discharge. In
contrast, water is not utilized in the actual mining of coal
in the U.S. at the present time except for dust allaying and
fire protection. Waste water handling and management is
required in most coal mining methods or systems to insure
the continuance of the mining operation and to improve the
efficiency of the mining operation. Water enters mines via
precipitation, groundwater infiltration, and surface runoff
where it can become polluted by contact with materials in
the coal, overburden material and mine bottom. This waste
water is discharged from the mine as mine drainage which may
require treatment before it can enter into navigable water.
The waste water from coal mining operations is unrelated, or
only indirectly related, to production quantities.
Therefore, raw waste loadings are expressed in terms of
concentration rather than units of production.
In addition to handling and treating mine drainage during
actual coal loading or coal production, coal mine operators
are faced with the same burden during idle periods. Waste
water handling problems are generally insignificant during
initial start-up of a new underground mining operation.
However, these problems continue to grow as the mine is
expanded and developed and, unless control technology is
employed may continue indefinitely as a pollution source
after coal production has ceased. Surface mines can be
somewhat more predictable in their production of waste water
pollutants. Waste water handling within a surface mine can
be fairly uniform throughout the life of the mine. It is
highly dependent upon precipitation patterns and control
technology employed, i.e.: use of diversion ditches, burial
of toxic materials, and concurrent reclamation. Without the
use of control measures at surface mines the problems of
waste water pollution would also grow and continue
indefinitely after coal production has ceased.
51
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In light, of the fact that waste water pollution does not
necessarily stop with mine closure, a decision must be made
as to the point at which a mine operator has fulfilled his
obligations and responsibilities for waste water control and
treatment at a particular mine site. This point will be
discussed in detail in Section VII - Control and Treatment
Technology.
The chemical characteristics of raw mine drainage is
determined by local and regional geology of the coal and
associated overburden. Raw mine drainage ranges from
grossly polluted to drinking water quality. Depending on
hydrologic conditions, water handling volumes at a mine can
vary from zero to millions of cubic meters per day within a
geographic area, coal field or even from adjacent mines.
Due to these widely varying waste water characteristics, it
was necessary to accumulate data over* the broadest possible
base. Effluent quality data presented for each industry
category includes minimum, maximum and average values.
These were derived from historical effluent data supplied by
the coal industry, various regulatory and research bodies,
and from effluent samples collected and analyzed during this
study.
There has been an extensive amount of historical data
generated in the past 15 years on waste water quality from
surface and underground coal mines and coal preparation
plants. The principal pollutants that characterize mine
drainage have, as a result, been known for many years.
Consequently, most water quality studies have limited the
spectrum of their investigations and analyses to those few
key parameters.
The waste water sampling program conducted during this study
had two primary purposes. First the program was designed to
compensate for the wide diversity of geologic, hydrologic
and mining conditions in the major producing coal fields by
obtaining representative waste water data for every coal-
producing state. Second, the scope of the waste water
analyses was expanded to include not only the previously
established group of important paramenters, but all elements
which could be present in mine drainage. The resultant list
of potential mine drainage pollutants for which analyses
were performed is included in Table 6, Section VI.
Waste water analysis data obtained during the study as well
as the historical data, indicated the following constituents
commonly increased in concentrations over background water
quality levels: acidity, total iron, dissolved iron.
52
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manganese, aluminum, nickel, zinc, total suspended solids,
total dissolved solids, sulfates, ammonia, fluoride and
strontium,
Data evaluation also revealed that there \were only minor
differences in the chemical characteristics of raw mine
drainage from surface and underground mines in similar
geologic settings.
Major differences were observed between the two classes of
raw mine drainage which are generally representative of
geographic areas. These differences reflect the nature of
the coal and overburden material and are unrelated to mine
type or size. To illustrate these differences, the raw mine
drainage data utilized in this study for waste
characterization is presented in Tables 1, 2, 3 and ft. This
data represents all untreated mine drainage samples
collected and analyzed during the initial study conducted in
the summer and fall of 1971.
Evaluation of all waste water sample data from mines
revealed that there were four basic types of effluent based
on water analysis: 1J acid mine drainage - untreated mine
drainage characterized as acid with high iron
concentrations, definitely requiring neutralization and
sedimentation treatment; 2) discharge effluent - untreated
mine drainage of generally acceptable quality, i.e., not
requiring neutralization or sedimentation; 3) sediment-
bearing effluent -mine drainage which has passed through
settling ponds or basins without a neutralization treatment;
a*»3 *) treated mine drainage - mine drainage which has been
neutralized and passed through a sedimentation process.
Means and standard deviations were computed and assessed for
treated, discharge, and sediment-bearing samples, in order
to evaluate the need for regional variations in effluent
limitations, additional statistical analyses were performed.
The analysis data for treated mine drainage indicated that,
for the most part, waste water treatment techniques
currently employed by the coal mining industry are capable
of reducing the concentrations of constituents of raw mine
drainage which are considered harmful to aquatic organisms
or are objectionable as to taste, odor, or color to
acceptable levels.
The data also indicated that discharge effluent and
sediment-bearing effluent quality was commonly superior to
the quality of treated .mine drainage from the most efficient
treatment plants, regardless of region. Based on this
53
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information, it. was determined that there was no need for
further waste categorization of the coal mining segment
other than by raw mine drainage characteristics, which are
in turn related to the type of treatment that is required.
The raw waste characteristics of coal preparation plant
process water are highly dependent upon the particular
process or recovery technique utilized in the operation.
Since process techniques generally require an alkaline media
for efficient and economic operation, process water does not
dissolve significant quantities of the constituents present
in raw coal. The principal pollutant present in coal
preparation plant process water is suspended solids. In
plants utilizing froth flotation (Stage 3 Preparation
Plants) for recovery of coal fines (-28 mesh) , process water
typically contains less total suspended solids than plants
which do not recover coal fines. Analyses of raw water
slurry (untreated process water from the wet cleaning of
coal) from several typical preparation facilities that do
not employ froth flotation are summarized in Table 5.
It is important to note that of the more than 180 coal
preparation facilities utilizing wet cleaning processes
investigated during this study (either through site visits
or industry supplied data) , over 60% in varying terrain and
geographic locations had or reported closed water circuits.
Of the plants visited which did not use closed water
circuits virtually all employed some form of treatment for
solids removal prior to discharge.
The waste characteristics of waste water from coal storage,
refuse storage and coal preparation plant ancillary areas is
characterized as being generally similar to the raw mine
drainage at the mine served by the preparation plant.
Geologic and geographic setting of the mine and the nature
of the coal mined affect the characteristics of these waste
waters.
For the most part water usage and discharges from coal
preparation facilities are similar to other industrial
processes, i.e., water is used in the process, and upon
plant shut-down water usage (and resultant discharge) is
eliminated.
Drainage from a preparation plant's refuse disposal area is
similar to a surface mine in that this waste water from a
refuse disposal area can continue to pollute after the
preparation plant is shut down or closed. Like a surface
mine, waste water handling volumes for a preparation plant1s
refuse disposal area is highly dependent on precipitation
54
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patterns. Control technology employed to control pollution
after shut down are similar to those employed at a surface
mine to control pollution after the mine is closed.
Based on these considerations and the industry
categorization the following waste characterization was
established;
Waste Characterization
a •
I Anthracite Mining, Bituminous Coal and
Lignite Mining
A. Acid or Ferruginous Raw Mine Drainage
1, Treated Mine Drainage
B. Alkaline Raw Mine Drainage
1. Discharge Effluent
2. sediment-bearing Effluent
II Anthracite Mining services. Bituminous Coal
and Lignite Mining services
A. Coal Preparation Plant Waste Water
B. Coal Storage, Refuse storage, and Coal
Preparation Plant Ancillary Waste Water
55
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TABLE 1
RAW MINE DRAINAGE CHARACTERISTICS
ALKALINE
- UNDERGROUND MINES
Parameters
pH
Alkalinity
Total Iron
Dissolved Iron
Manganese
Aluminum
Sine
Nickel
TDS
TSS
Hardness
Sulfate
Ammonia
Minimum
(mg/1)
6.6
22
0.03
0.01
0.01
0.01
0.01
0.01
418
1
52
10
0.02
Maximum
(mg/1)
8.5
1,8*0
9.10
0.95
0.41
0.60
0.30
0.02
22,658
76
1,520
1,370
4.00
Mean
(mg/1)
7.9
469
1.54
0.25
0.08
0.13
0.06
0.01
2,702
26
455
495
0.94
Std. Dev.
_
451
2.52
0.33
o.ii
0.12
0.07
0.002
5,034
23
445
426
1.17
56
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TABLE 2
RAW MINE DRAINAGE CHARACTERISTICS - UNDERGROUND MINES
ACID OR FERRUGINOUS
Parameters
pH
Alkalinity
Total iron
Dissolved Iron
Manganese
Aluminum
Zinc
Nickel
TDS
TSS
Hardness
Sulfate
Ammonia
Minimum
2.1
0
0.24
0.05
0.04
0.10
0.02
0.01
12
1
142
300
00
Maximum
(mg/1)
8.2
720
9,300
5,000
92
533
12.7
5.59
15,572
1,740
5,000
9,711
57
Mean
-------
TABLE 3
RAW MINE DRAINAGE CHARACTERISTICS
ALKALINE
- SURFACE MINES
Parameter
Minimum
(mg/1)
Maximum
(mg/1)
Mean
Std. Dev.
pH 6.2
Alkalinity 30
Total Iron 0.02
Dissolved Iron 0,01
Manganese 0.01
Aluminum 0.10
Zinc 0 -. 01
Nicfcel 0.01
TDS 152
TSS 1
Hardness 76
Sulfate 42
Ammonia 0.04
8.2
860
6.70
2.7
6.8
0.85
0.59
0.18
8,358
684
2,900
3,700
36
7.7
313
0.78
0.15
0.61
0.20
0.14
0.02
2,867
96
1,290
1,297
4.19
183
1.87
0.52
1.40
0.22
0.16
. 0.04
2,057
215
857
1,136
6.88
58
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TABLE 4
RAW MINE DRAINAGE CHARACTERISTICS - SURFACE MINES
ACID OR FERRUGINOUS
Parameter
pH
Alkalinity
Total Iron
Dissolved Iron
Manganese
Aluminum
Zinc
Nickel
TDS
TSS
Hardness
Sulfate
Ammonia
Minimum
(mg/1)
2.6
0
0.08
0.01
0.29
0.10
0.06
0.01
120
4
24
22
0.53
Maximum
(mg/1)
7.7
184
440
440
127
271
7.7
5
8f870
15,878
5,400
3,860
22
Mean
(mg/1)
3.6
5
52.01
50.1
45.11
71.2
1.71
0.71
4,060
549
1,944
1,842
6.48
Std. Dev.
32
101
102.4
42.28
79.34
1.71
1.05
3,060
2,713
1,380
1,290
4.70
59
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TABLE 5
RAW WASTE CHARACTERISTICS - COM. PREPARATION
PLANT PROCESS WATER
parameters
Minimum
(mg/1)
Maximum
(mg/1)
Mean
Std. Dev,
ph
Alkalinity
Total Iron
Dissolved Iron
Manganese •
Aluminum
Zinc
Nickel
TDS
TSS
Hardness
Sulfat.es
Ammonia
7.3
62
0,03
0
0.3
0.1
0.01
0,01
636
2,698
1,280
979
0
8.1
402
187
6.4
t.21
29
2.6
0.5i»
2,240
156,(VOO
1,800
1,029
U
7.7
160
«»7.8
0.92
1.67
10,62
0.56
0.15
1,433
62,448
1,540
1,004
2.01
96.07
59.39
2.09
1.14
11.17
0.89
0.19
543.9
8,372
260
25
1.53
60
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SECTION VI
SELECTIPN OF POLLUTANT PARAMETERS
CONSTITUENTS EVALUATED
As previously mentioned in Section V, the water quality
investigation preceding development of effluent guideline
recommendations covered a wide range of potential
pollutants. The study was initiated with a compilation of
chemical constituents which could be found in coal or its
overburden material. A complete list of analyses performed
on each water sample collected is presented in Table 6. The
analytical procedures used are in accordance with the
procedures published in the Federal Register, Vol. 38,
number 199, October 16, 1973.
GUIDELINE PARAMETER SELECTION CRITERIA
Selection of parameters for the purpose of developing
effluent limitation guidelines was based primarily on the
following criteria:
a. Constituents which are frequently present in mine
drainage in concentrations deleterious to aquatic
organisms.
b. Technology exists for the reduction or removal of
the pollutants in question.
c. Research data indicating that excessive concen-
trations of specific constituents are capable of
disrupting an aquatic ecosystem.
MAJOR PARAMETERS - RATIONALE FOR SELECTION OR REJECTION
Evaluation of all available effluent analysis data indicated
that the concentrations of certain mine drainage
constituents were consistently greater than the
concentrations considered deleterious to aquatic organisms
or the concentration capable of disrupting an aquatic
ecosystem.
The following were identified as the major pollutant
constituents in coal mine drainage.
Acidity Aluminum
Total Iron Nickel
61
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TABLE 6
POTMTIAL J:QHSTITOTENTS OF COAL
Majo r Cons 1 1 ruent s - To tal Minor Copstituenta -Total
Acidity Arsenic
Alkalinity Barium
Aluminum Cadmium
Boron Chromium
Calcium Copper
Chlorides Cyanide
Dissolved Solids Lead
Fluorides Mercury
Hardness Molybedenum
Iron Selenium
Magnesium
Manganese
Nickel. . .
Potassium
Silicon
Sbdiun
Strontium
Sulfatjes
Suspended Solids
Zinc
Ma4.or ConatituentB - Dissolved Minor Constituents - Pi a solved
Aluminum Arsenic
Boron Barium
Calcium Cadmium
Iron Chromium
Magnesium Copper
Manganese Lead
Hickel Mercury
Silicon Molybdenum
Strontium Selenium
Zinc
Additional Analyses
Acidity, net
Acidity, pH&
Ammonia
Color
Ferrous Iron
Oils*
P«
Specific Conductance
Turbidity
* Preparation Plants Only
-------
Dissolved Iron Zinc
Manganese Total Suspended Solids
sulfates Total Dissolved solids
Ammonia Fluorides
strontium
The major pollutant constituents identified in effluent
drainage from coal preparation plants are:
Acidity Total Suspended Solids
Total Iron Total Dissolved solids
Dissolved Iron Fluorides
Ammonia Sulfates
The parameters selected for establishing effluent limitation
guidelines and standards of performance for the coal
industry are presented, with the rationale for their
selection, in the following discussion.
PH, Acidity and Alkalinity
Acidity and alkalinity are reciprocal terms. Acidity is
produced by substances that yield hydrogen ions upon
hydrolysis and alkalinity is produced by substances that
yield hydroxyl ions. The terms "total acidity" and "total
alkalinity" are often used to express the buffering capacity
of a solution. Acidity in natural waters is caused by
carbon dioxide, mineral acids, weakly dissociated acids, and
the salts of strong acids and weak bases. Alkalinity is
caused by strong bases and the salts of strong alkalies and
weak acids.
The term pH is a logarithinic expression of the concentration
of hydrogen ions. At a pH of 7, the hydrogen and hydroxyl
ion concentrations are essentially equal and the water is
neutral. Lower pH values indicate acidity while higher
values indicate alkalinity. The relationship between pH and
acidity or alkalinity is not necessarily linear or direct.
Waters with a pH below 6.0 are corrosive to water works
structures, distribution lines, and household plumbing
fixtures and can thus add such constituents to drinking
water as iron, copper, zinc, cadmium and lead. The hydrogen
ion concentration can affect the "taste" of the water. At a
low pH water tastes "sour". The bactericidal effect of
chlorine is weakened as the pH increases, and i£ is
advantageous to keep the pH close to 7. This is very
significant for providing safe drinking water.
62
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Extremes of pH or rapid pH changes can exert stress
conditions or kill aquatic life! outright. Dead fish,
associated algal blooms, and foul stenches are aesthetic
liabilities of any waterway. Even moderate changes from
"acceptable" criteria limits of pH are deleterious to some
species. The relative toxicity to aquatic life of many
materials is increased by changes in the water pH.
Metalocyanide complexes can increase a thousand-fold in
toxicity with a drop of 1.5 pH units. The availability of
many nutrient substances varies with the alkalinity and
acidity. Ammonia is more lethal with a higher pfl.
The lacrimal fluid 6f the human eye has a pH of
approximately 7.0 and a deviation of 0.1 pH unit from the
norm may result in eye irritation for the swimmer,
Appreciable irritation will cause severe pain.
Due to the significant impact of low pH's and high acidities
on receiving streams and the fact that these parameters can
be easily controlled, effluent limitations have been
proposed for fchis parameter.
Total and Dissolved iron
Iron is one of the major pollutants of coal mine drainage,
and is frequently found in coal preparation plant drainage
in objectionable concentrations. Precipitated iron, in the
form of ferric hydroxide or ferric sulfate, blankets stream
bottoms, destroying aquatic life and aesthetically degrading
those streams. Both dissolved and suspended iron can pre-
cipitate on the gills of fish and can eventually accumulate
to lethal concentrations. Industrial and municipal water
supplies are affected by objectionable taste, staining, and
encrustation resulting from iron deposition.
Natural waters may be polluted by iron-bearing industrial
wastes such as those from pickling operations and by the
leaching of soluble iron salts from soil and rocks, e.g.
acid-mine drainage and iron-bearing ground water.
Although many of the ferric and ferrous salts such as the
chlorides are highly soluble in water, the ferrous ions are
readily oxidized in natural surface waters to the ferric
condition an<3 form insoluble hydroxides. These precipitates
tend to agglomerate, flocculate, and settle or be absorbed
on surfacesj hence, the concentration of iron in well
aerated waters is seldom high. In ground water, the pH may
be such that high concentrations of iron remain in solution.
63
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Iron la trace amounts is essential for nutrition. Indeed,
larger quantities of iron are taken for therapeutic
purposes. The daily nutritional requirement is 1 to 2 mg,
and most diets contain 7 to 35 mg per day, with an average
of 16.
Instead of physiological reasons, therefore, the limit is
based on esthetic and taste considerations, Iron and
manganese tend to pecipitate as hydroxides and stain laundry
and porcelain fixtures. It has also been reported that
ferric iron combines with the tannin in tea to produce a
dark violet color.
The taste threshold of iron in water has been given as 0.1
and 0.2 mg/1 of iron from ferrous sulfate and ferrous
chloride respectively. It has also been reported that
ferrous iron imparts a taste at 0.1 mg/1 and ferric iron at
0.2 mg/1.
Iron is an essential constituent of animal diets, but
animals are sensitive to changes in iron conentration. Cows
will not drink enough water if it is high in iron* and
consequently, milk production is affected.
Most of the references dealing with this beneficial use are
expressed in terms of specific iron salts. When iron is
added to water in the form of chlorides, sulfates, or
nitrates, the salt dissociates but the resulting ferrous or
ferric ions combine with hydroxyl ions to form precipitates.
Hence, very little of the iron remains in solution; but if
the dosage is sufficient and the water is not strongly
buffered, the addition of a soluble iron salt may lower the
pH of the water to a toxic level. Furthermore, the
deposition of iron hydroxides on the gills of fish may cause
an irritation and blocking of the respiratory channels.
Finally, heavy precipitates of ferric hydroxide may smother
fish eggs. When testing the effects of wastes from nail-
making plants on trout, stickleback, and perch with wastes
containing concentrations of chloride, hydrogen, ferric and
ferrous ions, concentrations of 1000 mg/1 of these mixed
salts killed most fish within a few hours, hardy stickleback
were not killed until five hours exposure to 2500 mg/1.
Much of the killing action was attributed to coatings of
iron oxide or hydroxide precipitates on the gills. The
toxicity of rion and iron salts depends on whether the iron
is present in the ferrous or ferric state and whether it is
in solution or suspension.
Crenothrix, Gallionella, and other iron bacteria utilize
iron as a source of energy and store it in their microbial
-------
protoplasm. They may accumulate in wells, treatment plants,
pipelines, anil othet water works structures; or they may
pass into the distribution system and cause customer
complaints. Trouble with this organism is experienced
frequently when the iron exceeds 0.2 mg/1.
Total and dissolved iron parameters can be relatively easily
controlled, since the same neutralization processes that
control acidity and pH cause iron to precipitate from
solution. As a result of these several factors, guidelines
have been developed for the limitation of total and
dissolved iron concentrations.
Total Suspended Solids
Suspended solids include both organic and inorganic
materials. The inorganic components include sand, 'Silt, and
clay. The organic fraction includes such materials as
grease, oil, tar, animal and vegetable fats, various fibers,
sawdust, hair, and various materials from sewers. These
solids may settle out rapidly and bottom deposits are often
a mixture of both organic and inorganic solids. They
adversely affect fisheries by covering the bottom of the
stream or lake with a blanket of material that destroys the
fish-food bottom fauna or the spawning ground of fish.
Deposits containing organic materials may deplete bottom
oxygen supplies and produce hydrogen sulfide, carbon
dioxide, methane, and other noxious gases.
In raw water sources for domestic use, state and regional
agencies generally specify that suspended solids in streams
shall not be present in sufficient concentration to be
objectionable or to interfere with normal treatment
processes. Suspended solids in water may interfere with
many industrial processes, and cause foaming in boilers, or
encrustations on equipment exposed to water, especially as
the temperature rises. Suspended solids are undesirable in
water for textile industries; paper and pulp; beverages;
dairy products; laundries; dyeing; photography; cooling
systems, and power plants. Suspended particles also serve
as a transport mechanism for pesticides and other substances
which are readily sorbed into or onto clay particles.
Solids may be suspended in water for a time, and then settle
to the bed of the stream or lake* These settleable solids
discharged with man's wastes may be inert, slowly
biodegradable materials, or rapidly decomposable substances.
While in suspension, they increase the turbidity of the
water, reduce light penetration and impair the
photosynthetic activity of aquatic plants.
65
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Solids in suspension are aesthetically displeasing. When
they settle to form deposits on the stream or lake bed, they
are often much more damaging to the life in water, and they
retain the capacity to displease the senses. Solids, when
transformed to sludge deposits, may do a variety of damaging
things, including blanketing the stream or lake bed and
thereby destroying the living spaces for those benthic
organisms that would otherwise occupy the habitat. When an
organic and therefore decomposable nature, solids use a
portion or all of the dissolved oxygen available in the
area. Organic materials also serve as a seemingly
inexhaustible food source for sludgeworms and associated
organisms.
Turbidity is principally a measure of the light absorbing
properties of suspended solids. It is frequently used as a
substitute method of quickly estimating the total suspended
solids when the concentration is relatively low.
As a result of these serious effects on receiving streams,
effluent limitations have been proposed for total suspended
solids in this report.
Manganese
The presence of manganese may interfere with water usage,
since manganese stains materials, especially when the pH is
raised as in laundering, scouring, or other washing
operations. These stains, if not masked by iron, may be
dirty brown, gray or black in color and usually occur in
spots and streaks. Waters containing manganous bicarbonate
cannot be used in the textile industries, in dyeing,
tanning, laundering, or in hosts of other industrial uses.
In the pulp and paper industry, waters containing above 0.05
mg/1 manganese cannot be tolerated except for low-grade
products. Very small amounts of manganese—0.2 to 0.3 mg/1
may form heavy encrustations in piping, while even smaller
amounts may form noticeable black deposits.
Nickel
Elemental nickel seldom occurs in nature, but nickel
compounds are found in many ores and minerals. As a pure
metal it is not a problem in water pollution because it is
not affected by, or soluble in, water. Many nickel salts,
however, are highly soluble in water.
Nickel is extremely toxic to citrus plants. It is found in
many soils in California, generally in insoluble form, but
excessive acidification of such soil may render.it soluble.
66
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causing severe injury to or the death of plants. Many
experiments with plants in solution cultures have shown that
nickel at 0.5 to 1.0 mg/1 Is inhibitory to growth.
Nickel salts can kill fish at very low concentrations. Data
for the fathead minnow show death occurring in the range of
5-H3 mg/1, depending on the alkalinity of the water.
Nickel is present in coastal and open ocean concentrations
in the range of 0,1 - 6.0 ug/1, although the most common
values are 2-3 ug/1. Marine animals contain up to 400
ug/1, and marine plants contain up to 3,000 ug/1. The
lethal limit of nickel to some marine fish has been reported
as low as 0.8 ppm. Concentrations of 13.1 mg/1 have been
reported to cause a 50 percent reduction of the
photosynthetic activity in the giant kelp {Macrocyjstia
•pyrifera) in 96 hours, and a low concentration was found to
kill oyster eggs.
Zinc
Occurring abundantly in rocks and ores, zinc is readily
refined into a stable pure metal and is used ejetensively for
galvanizing, in alloys, for electrical purposes, in printing
plates, for dye-manufacture and for dyeing processes, and
for many other industrial purposes. Zinc salts are used in
paint pigments, cosmetics, pharmaceuticalsr dyes,
insecticides, and other products too numerous to list
herein. Many of these salts {e.g., zinc chloride and zinc
sulfate) are highly soluble in water; hence it is to be
expected that zinc might occur in many industrial wastes.
On the other hand, some tine salts (zinc carbonate, zinc
oxide, zinc sulfide) are insoluble in water and consequently
it is to be expected that some zinc will precipitate and be
removed readily in most natural waters.
i
In zinc-mining areas, zinc has been found in waters in
concentrations as high as 50 mg/1 and in effluents from
metal-plating works and small-arms ammunition plants it may
occur in significant concentrations. In most surface and
ground waters, it is present only in trace amounts. There
is some evidence that zinc ions are adsorbed strongly and
permanently on silt, resulting in inactivation of the zinc.
Concentrations of zinc in excess of 5 mg/1 in raw water used
for drinking water supplies cause an undesirable taste which
persists through conventional treatment. Zinc'can have an
adverse effect on man and animals at high concentrations.
67
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In soft water, concentrations of zinc ranging from 0.1 to
1.0 mg/1 have been reported to be lethal to fish. Zinc is
thought to exert its toxic action by forming insoluble
compounds with the mucous that covers the gills, by damage
to the gill epithelium, or possibly by acting as an internal
poison. The sensitivity of fish to zinc varies with
species, age and condition, as well as with the physical and
chemical characteristics of the water. Some acclimatization
to the presence of zinc is possible. It has also been
observed that the effects of ziric poisoning may not become
apparent immediately, so that fish removed from zinc-
contaminated to zinc-free water (after 4-6 hours of exposure
to zinc) may die 48 hours later. The presence of copper in
water may increase the toxicity of zinc to aquatic
organisms, but the presence of calcium, or hardness may
decrease the relative toxicity.
Observed values for the distribution of zinc in ocean waters
vary widely. The major concern with zinc compounds in
marine waters is not one of acute toxicity, but rather of
the long-term sub-lethal effects of the metallic compounds
and complexes. From an acute toxicity point of view,
invertebrate marine animals seem to be the most sensitive
organisms tested. The growth of the sea urchin, for
example, has been retarded by as little as 30 ug/1 of zinc.
Zinc sulfate has also been found to be lethal to many
plants, and it could impair agricultural uses.
Effluent limitations have been proposed for aluminum,
manganese, nickel and zine because of their presence in raw
mine drainage in quantitites sufficient to seriously degrade
receiving waters. Significant reductions of these
constituents have been demonstrated in exemplary coal mine
drainage treatment plants, where they are achieved in
conjunction with simple acid neutralization.
Several additional parameters were identified in acid mine
drainage and coal preparation plant waste waters in
concentrations in excess of existing water quality
standards, but were not recommended for effluent limitation
guidelines. These parameters and the rationale for their
rejection in guideline establishment, are discussed below:
Total Dissolved solids
In natural waters the dissolved solids consist mainly of
carbonates, chlorides, sulfates, phosphates, and possibly
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nitrates of calcium, magnesium, sodium, and potassium, with
traces of iron, manganese and other substances.
Many communities in the United States and in other countries
use water supplies containing 2000 to 4000 mg/1 of dissolved
salts, when no better water is available, such waters are
not: palatable, may not quench thirst, and may have a
laxative action on new users. Waters containing more than
4000 mg/1 of total salts are generally considered unfit for
human use, although, in hot climates such higher salt
concentrations can be tolerated whereas they could not be in
temperate climates. Waters containing 5000 mg/1 or more are
reported to be bitter and act as bladder and intestinal
irritants. It is generally agreed that the salt
concentration of good, palatable water should not exceed 500
mg/1.
Limiting concentrations of dissolved solids for fresh-water
fish may range from 5,000 to 10,000 mg/1, according to
species and prior acclimatization. Some fish are adapted to
living in more saline waters, and a few species of fresh-
water forms have been found in natural waters with a salt
concentration of 15,000 to 20,000 mg/1. Fish can slowly
become acclimatized to higher salinities, but fish in waters
of low salinity cannot survive sudden exposure to high
salinities, such as those resulting from discharges of oil-
well brines. Dissolved solids may influence the toxicity of
heavy metals and organic compounds to fish and other aquatic
life, primarily because of the antagonistic effect of
hardness on metals.
Waters with total dissolved solids over 500 mg/1 have
decreasing utility as irrigation water. At 5,000 mg/1 water
has little or no value for irrigation.
Dissolved solids in industrial waters can cause foaming in
boilers and cause interference with cleaness, color, or
taste of many finished products. High contents of dissolved
solids also tend to accelerate corrosion.
Specific conductance is a measure of the capacity of water
to convey an electric current. This property is related to
the total concentration pf ionized substances in water and
water temperature. This property is frequently used as a
substitute method of quickly estimating the dissolved solids
concentration.
Although the level of total dissolved solids attributable to
the coal mining industry S9metimes exceeds accepted drinking
water standards, it generally does not approach levels toxic
69
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to plants or animals. In view of this, and the fact that
technology for economic dissolved solids reduction does not
exist, effluent limitations have not been proposed for this
parameter.
Sulfates
Due to overburden characteristics, drainages associated with
coal-producing and coal-processing facilities frequently
contain significant amounts of sulfates. While excessively
high concentrations of sulfates can affect the palatability
of drinking water, the effects on aquatic organisms are
minimal. Sulfates generally undergo little or no reduction
in normal neutralization facilities. For these reasons,
effluent limitations have not been proposed for this
parameter.
Fluorides
As the most reactive non-metal, fluorine is never found free
in nature but as a constituent, of fluorite or fluorspar,
calcium fluoride, in sedimentary rocks and also of cryolite,
sodium aluminum fluoride, in igneous rocks. -Owing to their
origin only in certain types of rocks and only in a few
regions, fluorides in high concentrations are not a common
constituent of natural surface waters, but they may occur in
detrimental concentrations in ground waters.
Fluorides are used as insecticides, for disinfecting brewery
apparatus, as a flux in the manufacture of steel, for
preserving wood and mucilages, for the manufacture of glass
and enamels, in chemical industries, for water treatment,
and for other uses.
Fluorides in sufficient quantity are toxic to humans, with
doses of 250 to t50 mg giving severe symptoms or causing
death.
There are numerous articles describing the effects of
fluoride-bearing waters on dental enamel of children; these
studies lead to the generalization that water containing
less than 0.9 to 1.0 mg/1 of fluoride will seldom cause
mottled enamel in children, and for adults, concentrations
less than 3 or 4 mg/1 are not likely to cause endemic
cumulative fluorosis and skeletal effects. Abundant
literature is also available describing the advantages of
maintaining 0.8 to 1.5 mg/1 of fluoride ion in drinking
water to aid in the reduction of dental decay, especially
among children.
70
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Chronic fluoride poisoning of livestock has been observed in
areas where water contained 10 to 15 mg/1 fluoride.
Concentrations of 30 - 50 mg/1 of fluoride in the total
ration of dairy cows is considered the upper safe limit.
Fluoride from waters apparently does not accumulate in soft
tissue to a significant degree and it is transferred to a
very small extent into the milk and to a somewhat greater
degree into eggs. Data for fresh water indicate that
fluorides are toxic to fish at concentrations higher than
1.5 mg/1.
Samples collected during this study indicate treatment plant
effluents routinely contain concentrations of 1 to 2 mg/1 of
fluorides. Since economic technology does not exist for
further removal at these relatively low levels, effluent
limitations have not been proposed for flourides.
strontium
Strontium is commonly found in drainage from coal mining
operations in concentrations slightly above those
recommended by existing water quality standards. Little
published data is available on toxic effects of strontium
and it is not known to interfere with municipal or
industrial water treatment processes. In addition,
technology has not been developed for economic removal of
strontium at relatively low concentrations. In light of its
apparently minimal impact on receiving stream quality and
the fact that it cannot be removed economically at low
concentrations, effluent limitations have not been proposed
for this constituent.
Ammonia
Ammonia is a common product of the decomposition of organic
matter. Dead and decaying animals and plants along with
human and animal body wastes account for much of the ammonia
entering the aquatic ecosystem. Ammonia exists in its un-
ionized form only at higher pH levels and is the most toxic
in this state. The lower the pH, the more ionized ammonia
is formed and its toxicity decreases. Ammonia, in the
presence of dissolved oxygen, is converted to nitrate (NO3)
by nitrifying bacteria. Nitrite (NO2) , which is an
intermediate product between ammonia and nitrate, sometimes
occurs in quantity when depressed oxygen conditions permit.
Ammonia can exist in several other chemical combinations
including ammonium chloride and other salts.
Nitrates are considered to be among the poisonous
ingredients of mineralized waters, with potassium nitrate
71
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being more poisonous than sodium nitrate. Excess nitrates
cause irritation of the mucous linings of the
gastrointestinal tract and the bladder; the symptoms are
diarrhea and diuresis, and drinking one liter of water
containing 500 mg/1 of nitrate can cause such symptoms.
Infant methemoglobinemia, a disease characterized by certain
specific blood changes and cyanosis, may be caused by high
nitrate concentrations in the water used for preparing
feeding formulae, while it is still impossible to state
precise concentration limits, it has been widely recommended
that water containing more than 10 mg/1 of nitrate nitrogen
(NO3-N) should not be used for infants. Nitrates are also
harmful in fermentation processes and can cause disagreeable
tastes in beer. In most natural water the pH range is such
that ammonium ions- (NHJH-J predominate. In alkaline waters,
however, high concentrations of un-ionized ammonia in
undissociated ammonium hydroxide increase the toxicity of
ammonia solutions. In streams polluted with sewage, up to
one half of the nitrogen in the sewage may be in the form of
free ammonia, and sewage may carry up to 35 mg/1 of total
nitrogen. It has been shown that at a level of 1.0 mg/1 un-
ionized ammonia, the ability of hemoglobin to combine with
oxygen is impaired and fish may suffocate. Evidence
indicates that ammonia exerts a considerable toxic effect on
all aquatic life within a range of less than 1.0 mg/1 to 25
mg/1, depending on the pH and dissolved oxygen level
present. j
Ammonia can add to the problem of eutrophication by
supplying nitrogen through its breakdown products. Some
lakes in warmer climates, and others that are aging quickly
are sometimes limited by the nitrogen available. Any
increase will speed up the plant growth and decay process.
Effluent limitations have not been proposed for ammonia
since the levels observed in coal mine drainage generally do
not warrant further concern. However, this parameter should
be considered as a routine analysis in future sampling
programs because of its sporadic presence in mine drainage.
If high concentrations of ammonia are consistently
identified in future sampling programs its impact on receiv-
ing waters may have to be re-evaluated.
72
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spoil off the bench onto downslope areas. This downslope
spoil material can slump or rapidly erode, and must be moved
upslope to the mine site if contour regrading is required.
The land area affected by contour strip mining is,
therefore, substantially larger than the area from which
coal is actually extracted. In block cut mining only
material from the first cut is deposited in adjacent low
areas. Remaining spoil is then placed in mined portions of
the bench. As a result, spoil handling is restricted to the
actual pit area in all but the first cut, significantly
reducing the area disturbed.
An initial cut is made from a crop line into the hillside to
the maximum highwall depth desired, and spoil is cast in a
suitable low area (see Figure 12). After removal of the
coal, spoil material from the succeeding cut is backfilled
into the previous cut, proceeding in one or both directions
from the initial cut. This simultaneously exposes the coal
for recovery and provides the first step in mine
reclamation. Provision can be made in this mining technique
for burial of toxic materials. On completion of coal
loading, most spoil material has already been replaced in
the pit, and the entire mine can be regraded with minimal
earth handling.
Reqrading. Surface mining usually requires removal of large
amounts of overburden to expose coal. Regrading involves
mass movement of material following coal extraction to
achieve a more desirable land configuration. Reasons for
regrading strip mined land are:
1) control water pollution
2) return usefulness to land
3) provide a suitable base for revegetation
4) bury pollution-forming materials
5) reduce erosion and subsequent sedimentation
6) eliminate landsliding
7) encourage natural drainage
8) eliminate ponding
9) eliminate hazards such as high cliffs and deep
pits
10) aesthetic improvement of land surface
Contour regrading is the current reclamation technique for
many of the Nation's active contour and area surface mines.
This technique involves regrading a mine to approximate
original land contour. It is generally one of the most
favored and aesthetically pleasing regrading techniques
because the land is returned to approximately its pre-mining
75
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-LEGEND.-
E53 Spoil Bank ••
Spoil Backfill
Outcrop Barrier
(As Required)
Cut I
Highwol!
Hilt
Diagram A
Valley
Cut 2
Cut I
Highwol!
Hill
Diagram 8
Valley
Cut 3
Hill
Diagram C
Valley
Hill
Diagram P
Cut 3
Volley
Valley
Hill
Diogrom F
Cut 5
Valley
BLOCK CUT
Figure 12
Adapted from drawing in
"A New Method of Surface „
Coal Mining in Steep Terrain
76
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
CONTROL TECHNOLOGY
Control technology, as discussed in this report, includes
techniques employed before, during and after the actual coal
mining, or coal loading, operation to reduce or eliminate
adverse environmental effects resulting from the discharge
of mine waste water. Effective pollution control
preplanning can reduce pollution formation at active mine
sites and minimize post-mining pollution potential.
Control technology, as discussed in this report, has been
categorized as to control technology as related to surface
mining, underground mining, and coal preparation.
Surface Mining
Surface mine pollution control technology is divided into
two major categories - mining technology (specific mining
techniques) and at-source reclamation technology. Surface
mining techniques can effectively reduce amounts of pollu-
tants exiting a mine either by containing them within the
mine or by reducing their formation. These techniques can
be combined with careful reclamation planning and imple-
mentation to provide maximum at-source pollution control.
Mining Techniques. Several techniques have been implemented
by industry to reduce environmental degradation during
actual stripping operations. Utilization of the box-cut
technique in moderate and shallow slope contour mining has
increased in recent years.
A box-cut is simply a contour strip mine in which a low wall
barrier is maintained (see Figure 11). This mining
technique significantly reduces the amount of waste water
discharged from a pit area, since that waste water can no
longer seep from the pit through spoil banks. However, as
in any downslope disposal technique, the problem of
preventing slide conditions, spoil erosion, and resultant
stream sedimentation is still present.
Block cut mining was developed to keep spoil materials off
the down slope and to facilitate contour regrading, minimize
overburden handling, and contain spoil within mined areas.
Contour stripping is typically accomplished by throwing
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•Original Ground Surface
Highwall
Stockpiled
Spoil Material
Temporary Megetatton
Low Wall
Barrie v
/**
•Coal Seam
Pit FIoo
CROSS SECTION OF BOX CUT
Figure II
-------
state. TMs technique is also favored because nearly all
spoil is placed back in the pit, eliminating steep davnslope
spoil banks and reducing the size of erodable reclaimed
area. Contour regrading facilitates deep burial of
pollution-forming materials and minimzes contact time
between regraded spoil and surface runoff, thereby reducing
pollution formation. Erosion potential, on the other hand,
can be increased by this regrading technique if precautions
are not implemented to avoid long, unbroken sLqpes.
In area and contour stripping there may be other forms of
reclamation that provide land configurations and slopes
better suited to the intended uses of the land. This can be
particularly true with steep-slope contour strips, where
large highwalls and steep final spoil slopes limit
application of contour regrading. Surface mining can be
prohibited in such areas due to difficult reclamation using
contour regrading, although there may be regrading
techniques that could be effectively utilized. In addition,
where extremely thick coal seams are mined beneath shallow
overburden, there may not be sufficient spoil material
remaining to return the land to original contour.
are several other reclamation techniques of varying
effectiveness which have been utilized in both active and
abandoned mines. These techniques include terrace, swale,
swallow-tail, and Georgia V-ditch, several of which are
quite similar in nature. In employing these techniques, the
upper hlghwall portion is frequently left exposed or
backfilled at a steep angle, with the spoil outslope
z?emaining somewhat steeper than original contour (see Figure
13) . In all cases, a terrace of some form remains where the
originally bench was located, and there are provisions for
rapidly channeling runoff from the spoil area. Such
terraces may permit more effective utilization of surface
mined land in many cases.
Disposal of excess spoil material is frequently a problem
where contour backfilling is not practiced. However, the
same problem can also occur, although less ccmmonly, where
contour regrading is in use. Some types of overburden rock,
particularly tightly packed sandstones, substantially expand
in volume when they are blasted and moved. As a result,
there may be a large volume of spoil material that cannot be
returned to the pit area, even when contour backfilling is
employed. To solve this problem, head-of -hollow fill has
been used for overburden storage. OSaa extra overburden is
placed in narrow, steep-sided hollows in compacted layers
].2 to 2.4 rosters (4 to 8 ft) thick and graded to enable
surface drainage (see Figures 14 and 15) .
77
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•Original Ground Surface
'Diversion Difch
•Highwoll
00
Adopted from drawing In
SURFACE MINING METH-
ODS AND TECHNJQUES
(1972)
Backfilled Ground
Surface
Lowwall
Barrier
•Pit Floor Coal Seam"
CROSS SECTION OF NON-CONTOUR REGRADING
Figure 13
-------
Highwall-'
Strip Mine Bench
Fill Area
Crowned
Terraces
PLAN
Crowned
terrace
Original Ground Surface
High wall
Fill
Lateral Drain
Rock Filled
Natural Drain way
CROSS SECTION
TYPICAL HEAD-OF-HOLLOW FILL
Figure 14
Adapted from drawing in
SURFACE MINING METH-
ODS AND TECHNIQUES
(1972)
79
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•'L 1
Coal
-Original Ground Surface
Spoil Storage
i
\
\
X S
SPOIL STORAGE DURING MINING
Backfilled Ground Surf ace
REGRADED AREA AFTER MINING
CROSS SECTION
TYPICAL HEAD-OF-HOLLOW FILL
Figure 15
-------
In this regrading and spoil storage technique, natural
ground is cleared of woody vegetation and rock drains are
constructed where natural drains exist, except in areas
where inundation has occurred. This permits ground water
and natural percolation to exit fill areas without
saturating the fill, thereby reducing potential landslide
and erosion problems. Normally the face of the fill is
terrace graded to minimize erosion of the steep outslope
area.
This technique of fill or spoil material deposition, has
been limited to relatively narrow, steep-sided ravines that
can be adequately filled and graded. Design considerations
include the total number of acres in the watershed above a
proposed head-of-hollow fill, as well as the drainage, slope
stability, and prospective land use. Revegetation usually
proceeds as soon as erosion and siltation protection has
been completed. This technique is avoided in areas where
under-drainage materials contain high concentrations of
pollutants, since resultant drainage would require treatment
to meet pollution control requirements.
Erosion Control. Although regrading is an essential part of
surface mine reclamation, it cannot be considered a total
reclamation technique. There are many other facets of
surface mine reclamation that are equally important in
achieving successful reclamation. The effectiveness of
regrading and other control techniques are interdependent;
Failure of any phase could severely reduce the effectiveness
of an entire reclamation project.
The most important auxiliary reclamation procedures employed
at regraded surface mines or refuse areas are water
diversion and erosion and runoff control. Water diversion
involves collection of water before it enters a mine area
and conveyance of that water around the mine site. Water
diversion is usually included in the mining method, or
system, to protect the mine and increase the efficiency of
mining. This procedure also decreases erosion and pollution
formation. Ditches, flumes, pipes, trench drains and dikes
are all commonly used for water diversion. Ditches are
usually excavated upslope from a mine site to collect and
convey water. Flumes and pipes are used to carry water down
steep slopes or across regraded areas. Riprap and dumped
rock are sometimes used to reduce water velocity in the
conveyance system.
Diversion and conveyance systems are designed to accomodate
predicted water volumes and velocities. If capacity of a
81
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ditch is exceeded, water erodes the sides and renders the
ditch ineffective.
Drainways at the bases of highwalls intercept and divert
discharging ground water. In some instances, ground water
above the mine site is pumped out before it enters the mine
area. Soil erosion is significantly reduced on regraded
areas by controlling the course of surface water runoff,
using interception channels constructed on the regraded
surface {see Figure 16) .
Water that reaches a mine site can cause serious erosion,
sedimentation and pollution problems;**,, Runoff control
techniques are available to effectively deal with this
water, but some of these techniques may conflict with
pollution control measures. Control of pollutants forming
at a mine frequently involves reduction of water
infiltration, while runoff controls to prevent erosion can
produce increased infiltration, which can subsequently
increase pollutant formation.
There are a large number of techniques in use for
controlling runoff, with highly variable costs and degrees
of effectiveness. Mulching is sometimes used as a temporary
runoff and erosion control measure, since it protects the
land surface from raindrop impacts and reduces the velocity
of surface runoff.
Velocity reduction is a critical facet of runoff control.
This is accomplished through slope reduction by either
terracing or grading, revegetation or use of flow
impediments such as scarification, dikes, contour plowing
and dumped rock. Surface stabilizers have been utilized on
the surface to temporarily reduce erodability of the
material itself, but expense has restricted use of such
materials.
Reveqetation. Establishment of good vegetative cover on a
mine area is probably the most effective method of con-
trolling waste water pollution and erosion. A critical
factor in mine revegetation is the quality of the soil or
spoil material on the surface of a regraded mine. There are
several methods by which the nature of this material has
been controlled. Topsoil segregation during stripping is
mandatory in many States. This permits topsoil to be
replaced on a regraded surface prior to revegetation.
However, in many forested, steep-sloped areas there is
little or no topsoil on the undisturbed land surface. In
such areas, overburden material is segregated in a manner
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CO
co
V**?*****
Regraded Spoilt
, _ _, ^
0rigina! Ground " Surface
WATER DIVERSION S EROSION CONTROL
(CONTOUR REGRAD1NG)
Figure 16
Adapted from drawing in
STUDY OF STRIP AND
SURFACE MINING IN
APPALACHIA (1966)
-------
that, will allow the most toxic materials to be placed at. the
base of the regraded mine, and the best spoil material is
placed on the regraded mine surface.
Vegetative cover provides effective erosion control, contri-
butes significantly to chemical pollution control, results
in aesthetic improvement, and can return land to agricul-
tural, recreational, or silvicultural usefulness. A dense
ground cover stabilizes the surface with its root system,
reduces velocity of surface runoff, helps build humus on the
surface and can virtually eliminate erosion. A soil profile
begins to form, followed by a complete soil ecosystem. This
soil profile acts as an oxygen barrier, reducing the amount
of oxygen reaching underlying pollution forming materials.
This in turn reduces oxidation, which is responsible for
most pollution formation.
The soil profile also tends to act as a sponge that retains
water near the surface, as opposed to the original loose
spoil which allowed rapid infiltration. This water
evaporates from the mine surface, cooling it and enhancing
vegetative growth. Evaporated water also bypasses toxic
materials underlying the soil, decreasing pollution
production. The vegetation itself also utilizes large
quantities of water in its life processes, and transpires it
back to the atmosphere, again reducing the amount of water
reaching underlying materials.
Establishment of an adequate vegetative cover at a mine site
is dependent on a number of related factors. The regraded
surface of many spoils cannot support a good vegetative
cover without supplemental treatment. The surface texture
is often too irregular, and may require raking to remove as
much rock as possible, and to decrease the average size of
the remaining material. Materials toxic to plant life are
usually buried during regrading, and generally do not appear
on or near the final graded surface. Dark-colored shaly
materials which cause extremely high surface temperatures
when left exposed, are often mixed with light materials to
enhance vegetative growth. In addition, if the surface is
compacted, it is usually scarified by discing, plowing or
roto-tilling prior to seeding in order to permit maximum
plant growth.
Soil supplements are often required to establish a good
vegetative cover on surface-mined lands and refuse piles,
which are generally deficient in nutrients. Mine spoils are
often acidic, and lime must be added to adjust pH to the
tolerance range of species to be planted. it may be
necessary to apply additional neutralizers to revegetated
84
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minimize erosion and sedimentation. A diverse and permanent
vegetative cover must be established and plant succession at
least equal in extent of cover to the natural vegetation of
the area. To assure compliance with these requirements and
permanence of vegetative cover, the operator should be held
responsible for successful revegetation and waste water
quality for a period of five years after the last year of
augmented seeding, fertilization, irrigation. Or waste water
treatment. In areas of the country where the annual average
precipitation is twenty-six inches or less, the operator's
assumption of responsibility and liability should extend for
a period of ten years after the last year of augmented
seeding, fertilization, irrigation or waste water treatment.
Underground Mining
Pollution control technology in underground mining is
largely restricted to at-source methods of reducing water
influx into mine workings. Infiltration from strata
surrounding the workings is the primary source of water.
This water can react with air and pyrite within the mines to
form acid mine drainage, or the water may only become
polluted with suspended solids. Underground mines are,
therefore, faced with problems of waste water handling, and
mine drainage treatment.
Infiltration generally results from rainfall recharge of a
ground water reservoir. ROck fracture zones and faults have
a strong influence on ground water flow patterns, since they
can collect and convey large volumes of water. These zones
and faults can intersect any portion of an underground mine
and permit easy access of ground water. Infiltration also
results from seepage from adjacent mines in the same seam.
The adjacent mine can be deep or surface and be active or
abandoned. This seepage is through barrier pillars left
between a flooded mine or flooded portion of a mine and the
active deep mine.
In some mines, infiltration can result in huge volumes of
waste water that must be handled, and possibly treated,
every day. Pumping can be a major part of the mining
operation in terms of equipment and expense, particularly in
mines which do not discharge by gravity.
Water infiltration control techniques, designed to reduce
the amount of water entering the workings, are extremely
important in underground mines located in or adjacent to
water-bearing strata. These techniques are often employed
in such mines to decrease the volume of waste water
requiring handling and treatment.
-------
Revegetation of arid and semi-arid areas involves special
consideration because of the extreme difficulty to establish
vegetation. Lack of rainfall and effects of surface distur-
bance create hostile growth conditions. Because mining in
arid regions has only recently been initiated on a large
scale, there is no standard revegetation technology.
Experimentation and demonstration projects exploring two
general revegetation techniques - moisture retention and
irrigation, are currently being conducted to develop this
technology.
Moisture retention utilizes entrapment, concentration and
preservation of water within a soil structure to support
vegetation. This may be obtained utilizing snow fences,
mulches, pits, slot chiseling, gouging, offset listering.
Irrigation can be achieved by pumping or gravity feed
through either pipes or ditches. This technique can be
extremely expensive, and acquisition of water rights may
present a major problem. Use of these arid climate
revegetation techniques in conjunction with careful
overburden segregation and regrading should permit return of
arid mined areas to their natural state.
Mine Closure and Operators Responsibility
Reclamation is recognized as a control technology for
surface mining. A surface mine operator can terminate his
responsibility for mine waste water by employing complete
reclamation.
The desired reclamation goals of regulatory agencies are
usually universal: the restoration of affected lands to a
condition at least fully capable of supporting the uses
which it was capable of supporting prior to any mining, and
achievement of a stability which does not pose any threat of
water diminution or pollution. The point at which this
metamorphosis takes place between unreclaimed and reclaimed
surface mined land is difficult to determine, but must be
considered in establishing a surface mine operator1s term of
responsibility for the quality of waste water from the
mined area.
In order to accomplish the objectives of the desired
reclamation goals, it is mandatory that the surface mine
operator regrade and re vegetate the disturbed area upon
completion of mining. The final regraded surface
configuration is dependent upon the ultimate land use of the
specific site, and control practices described in this
report can be incorporated into the regrading plan to
87
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areas for some time to offset continued pollutant
generation.
Several potentially effective soil supplements are currently
undergoing research and experimentation. Fly ash is a waste
product of coal-fired boilers and resembles soil in certain
physical and chemical properties. Fly ash disposal has
always been a problem, and use of fly ash on regraded
surfaces is promising because most fly ash is generated in
or near the coal fields. It is often alkaline, contains
some plant nutrients, and possesses moisture~retaining and
soilconditioning capabilities. Its main function is that of
an alkalinity source and a soil conditioner, although it
must usually be augmented with lime and fertilizers.
However, fly ash can vary drastically in quality,
particularly with respect to pH, and may contain leachable
materials capable of producing water pollution. Future
research, demonstration and monitoring of fly ash
supplements will probably develop its potential use.
Limestone screenings are also an effective long term neutra-
lizing agent on acidic spoils. Such spoils generally
continue to produce acidity as oxidation continues. Use of
lime for direct planting upon these surfaces is effective,
but provides only short term alkalinity. The lime is
usually consumed after several years, and the spoil may
return to its acidic conditions. Limestone screenings are
of larger particle size and should continue to produce
alkalinity on a decreasing scale for many years, after which
a vegetative cover should be well established. Use of large
quantities of limestone should also add alkalinity to
receiving streams. These screenings are often cheaper than
lime, providing larger quantities of alkalinity for the same
cost. Such applications of limestone are currently being
demonstrated in several areas.
Ose of digested sewage sludge as a soil supplement also has
good possiblities to replace fertilizer and simultaneously
alleviate the problem of sludge disposal. Besides supplying
various nutrients, sewage sludge can reduce acidity or
alkalinity, and effectively increase soil absorption and
moisture retention capabilities. Digested sewage sludge can
be applied in liquid or dry form, and must be incorporated
into the spoil surface. Liquid sludge applications require
large holding ponds or tank trucks from which sludge is
pumped and sprayed over the ground, allowed to dry, and
disced into the underlying material. Dry sludge application
requires dryspreading machinery, and must be followed by
discing.
85
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Limestone, digested sewage sludge, and fly ash are all
limited by their availability and chemical composition.
Unlifce commerical fertilizers, the chemical composition of
these materials may vary greatly, depending on how and where
they are produced. Therefore, a nearby supply of .these
supplements may be useless if it does not contain the nut-
rients or pH adjusters that are deficient in the area of
intended application. Fly ash, digested sewage sludge, and
limestone screenings are all waste products of other
processes, and are therefore usually inexpensive. The major
expense related to utilization of any of these wastes is the
cost of transporting and applying the material to the mine
area. Application may be quite costly, and must be uniform
to affect complete and even revegetation.
When such large amounts of certain chemical nutrients are
utilized it may also be necessary to institute controls to
prevent chemical pollution of adjacent waterways. Nutrient
controls may consist of pre-selection of vegetation to
absorb certain chemicals, or construction of berms and
retention basins where runoff can be collected and sampled,
after which it can be discharged or pumped back to the
spoil. The specific soil supplements and application rates
currently employed are selected to provide the best possible
conditions for the vegetative species that are to be
planted.
Careful consideration is given to species selection in
surface mine reclamation. Species are selected according to
some land use plan, based upon the degree of pollution
control to be achieved and the site environment, A dense.
ground cover of grasses and legumes is generally planted, in
addition to tree seedlings, to rapidly check erosion and
siltation. Trees are frequently planted in areas of poor
slope stability to help control landsliding. Intended
future use of the land is an important consideration with
respect to species selection. Reclaimed surface-mined lands
are occasionally returned to high use categories such as
agriculture, if the land has potential for growing crops.
However, when toxic spoils are encountered, agricultural
potential is greatly reduced and only a few species will
grow.
Environmental conditions, particularly climate, are
important in species selection. Usually, species are
planted that are native to an area, and particularly species
that have been successfully established on nearby mines with
similar climate and spoil conditions.
86
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Decreased waste water volumes, however do not necessarily
mean that pollution loads will also decrease. In
underground coal mines producing acid mine drainage, oxygen,
rather than volume of water flowing through the workings, is
the principal controlling factor in pollutant formation.
High humidity in a mine atmosphere usually contains
sufficient moisture to permit pollutant formation, while
water flowing through the mine merely transports pollutants
from their formation sites on the mine walls and floor. If
the volume of this transporting medium decreases while the
volume of pollutants remains unchanged, the resultant
smaller discharge will have increased pollutant
concentrations and approximately the same pollution load.
Formation of pollutants can be significantly reduced in
intercepted water, however, by reducing the contact time
within the mine.
Reduction in discharge volume can significantly reduce waste
water handling costs. Costs for waste water treatment will
decline even though concentrations may increase. The same
amounts of neutralizing agents will be required since the
pollution loads are basically unchanged. However, the
volume of waste water to be treated will be reduced signifi-
cantly, along with the size of the required treatment or
settling facilities. This cost reduction, along with cost
savings attributable to decreased pumping volumes, makes use
of water infiltration control techniques highly desirable.
Most water entering underground mines passes vertically
through the mine roof from overlying strata. Horizontal
permeability is characteristically much greater than
vertical permeability in rock units overlying coal mines.
These rock units generally have well developed joint
systems, which tend to cause vertical flow. Roof collapse
can also cause widespread fracturing in strata adjacent to
the roof, and subsequent joint separation far above the
roof. These opened joints can tap overlying perched
aquifers, or occasionally a flooded mine above the active
mine. Roof collapse in shallow mines will often cause
surface subsidence, which collects and funnels surface
runoff directly to the mine.
Such fracturing of overlying strata is commonly reduced by
employing any or all of the following:
1) increasing pillar size
2) support of the roof immediate to the coal
3) limiting mine entry widths, or number of entries
H) backfilling of mine voids
89
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These practices, when utilized to their fullest capability,
can assist in controlling mine roof collapse and subsequent
fracturing of overlying strata in deep mines with shallow
cover.
Boreholes and fracture zones, which act as water conduits to
underground mines are also sealed to prevent infiltration.
Boreholes remaining from earlier exploration efforts can be
present at underground mines. These boreholes ^are often
located from the mine and plugged hydraulically with
concrete to prevent passage of water. Difficulties are
encountered when sealing must be performed from the surface,
since abandoned holes are often difficult to locate on the
surface and may be blocked by debris.
Fracture zones, which are usually vertically oriented,
planar type features, are often major conduits of water.
Their locations can be plotted by experienced personnel
using aerial photography. Permeability of these zones is
reduced by drilling and grouting. Figure 17 illustrates the
sealing of boreholes and fracture zones.
Surface mines can be responsible for collecting and
conveying large quantities of surface water to adjacent or
underlying underground mines. Ungraded surface mines often
collect water in open pits where no surface exit point is
available. That water subsequently enters the ground water
system, from which it percolates into underground mine
workings (see Figure 18). A surface mine does not have to
intercept underground mine workings in order to increase
infiltration. Surface mines updip from underground mines
collect water and allow it to enter permeable coal seams.
This water then flows through or near the coal seam into the
mine workings. The influx of water to underground mines
from either active or abandoned surface mines can be
significantly reduced through implementation of a well-
designed reclamation plan.
The only actual underground mining technique developed
specifically for pollution control is preplanned flooding.
The technique is primarily one of mine design, in which a
mine is planned from its inception for post-operation
flooding or zero discharge. In drift mines and shallow
slope or shaft mines this is generally achieved by driving
the mine exclusively to the dip and pumping out all water
that collects in the workings. Upon completion of mining
activities, the workings are allowed to flood naturally,
eliminating the acid-producing pyrite-oxygen contact (see
Figure 19) . This technique should also include the design
of the mine's support and barrier pillars. Discharges, if
90
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BOREHOLE AND FRACTURE SEALING
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fc. ,- I 1 ICOftL SEAMtlBHiHI
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Pumping Required
During Mining
Coal Barrier
Underground Mine
/—Ground Water Level
/ (During Mining)
~ '~^'*^****>»x^ JT~~ Ground
#~Mr«M»..4_2w* Surface
Final Ground Water Level
Coal Barrier
Inundated Underground Mine
Ground Surface
PREPLANNED FLOODING
Figure l9 Adapted from drawing In
MINE DRAINAGE POLLUT-
ION PREVENTION AND
ABATEMENT USING HY-
OROGEOLOGICAL AND
GEOCHEMICAL SYSTEMS
-------
any, from a flooded mine should contain a much lower
pollutant concentration.
MINE CLOSURE AND OPERATORS RESPONSIBILITY
Unless control and treatment technology is implemented, an
underground mine can be a permanent source of water
pollution after mine closure.
Responsibility for the prevention of any adverse
environmental impacts from the temporary or permanent
closure of a deep mine should rest solely and permanently
with the mine operator. This constitutes a substantial
burden, and it therefore behooves the operator to make use
of the best technology available for dealing with pollution
problems associated with mine closure. The two techniques
most frequently utilized in deep mine water pollution
abatement are continuing waste water treatment and mine
sealing. Waste water treatment technology is well defined
and is generally capable of producing acceptable effluent
quality. If the mine operator chooses this course, he is
faced with the prospect of costly permanent treatment of
each mine discharge.
Mine sealing is an attractive alternative to the prospects
of perpetual treatment. Mine sealing requires the mine
operator to consider barrier and pillar design from the
perspective of strength, mine safety, the ability to
withstand high water pressure, and in the role of retarding
ground water seepage. In the case of new mines these
considerations should be included in the mine design to
cover the eventual mine closure. In the case of existing
mines these considerations should be evaluated for existing
mine barriers and pillars, and the future mine plan adjusted
to include these considerations if mine sealing is to be
employed at mine closure.
Sealing eliminates the mine waste water discharge and
inundates the mine workings, thereby reducing or terminating
the production of pollutants. However, the possibility of
the failure of mine seals or outcrop barriers increases with
time as sealed mine workings gradually become inundated by
groundwater and the hydraulic head increases. Depending
upon the rate of groundwater influx and size of the mined
area, complete inundation of a sealed mine may require
several decades. consequently, the maximum anticipated
hydraulic head on the mine seals may not be realized for
that length of time. In addition, seepage through, or
failure of, the coal outcrop barrier or mine seal could
occur at any time. Therefore, it seems reasonable to
93
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require the mine operator to permanently maintain the seals
or provide treatment in the event of significant seepage or
failure of the seals or barriers.
Coal Preparation
Water pollution problems associated with coal cleaning
processes are of two general types: (1) process generated
waste waters and (2) waste water in the vicinity of plant
facilities, coal storage areas, and refuse disposal areas.
Coal preparation pollution technology is therefore divided
into two major categories - process generated waste water
control and treatment and preparation plant ancillary area
waste water control and treatment techniques. With proper
management and planning, water pollution resulting from the
preparation of coal can be minimized. Process generated
waste water treatment and control technologies are dependent
on the coal preparation process employed.
Prgqejss Waste Water Control and Treatment
Fine coal and mineral particles, such as clays, remain
suspended in plant waters resulting in potentially serious
pollution from some coal cleaning facilities, clarification
techniques available for removal of these suspended solids
include thickeners, flocculation, settling, vacuum
filtration and pressure filtration, A typical closed
circuit washery could incorporate thickeners or settling
ponds with the. addition of flocculation reagents to enhance
settling of particulate matter. Coal fines separated from
plant waters can either be blended with clean coal or
transported to a refuse disposal site.
Froth flotation is a unit operation in coal cleaning that
provides separation of fine coal from refuse and fine clay.
Past industry practices limited froth flotation use to
metallurgical grade coals because the additional
preparation costs could not Jbe justified with the low
selling prices of utility coal. Present market conditions
may stimulate more operators to employ froth flotation cells
for recovery of a salable product from coal slimes. The
refuse and fine clays segregated by flotation are then
removed from plant waters via thickeners and filters. This
provides an economic method for effecting water
clarification.
In addition to removal of suspended solids, washery waters
may also require treatment to control chemical parameters.
Such as pH, iron, sulfates, etc. Such treatment when
required, is relatively simple, and is tied to the
94
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maintenance of efficient plant operation, acceptable product
quality, and minimal pollution - related stress on
equipment. Where chemical treatment is required, the most
common practice is addition of lime to make-up waters, but
treatment can also be performed prior to recycle of waters
from settling ponds. As a final resort, process waters may
require circulation through neutralization and treatment
facilities. This particular water control practice is not
common among existing preparation plants, and should only be
considered for extremely poor quality process waters.
Ancillary Rrea Waste Water Control
Pollution control technology related to preparation plant
ancillary areas is generally aimed at prevention of
contamination of surface waters (streams, impoundments and
surface runoff). Solicitous planning of refuse disposal is
a prime control method. Disposal sites are isolated from
surface flows and impoundments to minimize pollution
potential. In addition the following techniques are
practiced to prevent water pollution:
1) Construction of a clay liner beneath the planned
refuse disposal area to prevent infiltration of
surface waters (precipitation) into the groundwater
system,
2) Compaction of refuse to reduce infiltration and
help prevent spontaneous combustion.
3) Maintenance of a uniformly sized refuse to insure
good compaction (may require additional crushing).
ft) Following achievement of the desired refuse depth,
construction of a clay liner over the material to
minimize infiltration. This is usually succeeded
by placement of topsoil and seeding to establish a
vegetative cover for erosion protection.
5J Excavation of diversion ditches surrounding the
refuse disposal site to exclude surface runoff from
the area. Ditches can also be used to collect
runoff and seepage from refuse piles with
subsequent treatment if necessary.
6) Ponds or ditches to protect against overflow in
slurry refuse dams. Slurry refuse disposal
requires safety considerations in addition to
environmental.
95
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As previously indicated, the immediate area surrounding
preparation plant facilities presents another waste water
pollution problem requiring careful planning. Haul roads,
refuse disposal piles, and outside raw and clean coal
storage areas are sources of contamination to near-by
surface waters. The elimination of this contamination and
the maintenance of environmental quality are
responsibilities which must be borne by the coal preparation
plant operator. Several current industry practices to
control this pollution are:
1) Construction of ditches surrounding preparation
facilities to divert surface runoff and collect
seepage that does occur.
2) Installation of a hard surface over the entire area
with proper slopes to direct drainage to a sump.
As is the case in the previous technique, collected
waters are pumped into the preparation plant for
processing.
3) Storage of coal in bins, silos or hoppers with
pavement of haul roads and loading points. Runoff
is collected in trenches.
4) Establishment of a good vegetative cover of grasses
on the surface surrounding preparation facilities
to control erosion and sedimentation and to improve
aesthetics.
Plant Closure and Operators Responsibility
As with coal mines, the waste water pollution from a
preparation plant's refuse storage area does not stop upon
shutdown of the preparation plant. In that reclamation
goals and methods are similar to those for surface coal
mines, the operator should be held responsible for
successful revegetation and waste water quality for a period
of five years after the last year of augmented seeding,
fertilization, irrigation, or waste water treatment. In
areas of the country where the annual average precipitation
is twenty-six inches or less, the operators responsibility
and liability should extend for a period of ten years after
the last year of augmented seeding, fertilization,
irrigation, or waste water treatment.
-------
TREATMENT TECHNOLOGY
As discussed in Section IV, Industry categorization, coal
mines have been grouped into two separate raw mine drainage
categories. The pollutants encountered in these categories
were discussed in Waste Characterization - Section V. The
current treatment technology and industry practice for acid
or ferruginous and alkaline categories is described herein.
Acid or Ferruginous Mine Drainage
Acid or ferruginous mine drainage is most frequently
encountered in the northern Appalachian states. In
Pennsylvania, Ohio, Maryland,"-and northern West Virginia the
raw mine drainage usually contains varying degrees of
mineral acidity with significant concentrations of iron,
aluminum, calcium, manganese, and sulfates, and lesser
amounts of magnesium, nickel, zinc, ammonia, fluorides and
chlorides. Such drainages may also be found in other
localized areas.
Where acid or ferruginous mine drainage is a common problem,
there are generally existing state laws requiring that the
drainage be treated to remove those pollutants considered
harmful to receiving streams. Acid mine drainage treatment
facilities were in operation at 62 of the mining operations
visited and samples were collected of both the influent to
the treatment facility and the effluent from, the treatment
facility. This includes a sampling program at six selected
AMD treatment facilities where influent and effluent samples
were collected for 90 days consecutively.
Treated mine drainage has been established as a separate
class of coal mine effluent for purposes of establishing
limitation guidelines for acid or ferruginous mine drainage.
Treated Mine Drainage
Treatment facilities are now in operation at an estimated
250 mines that have an acid mine drainage. Most of these
are located in the northern Appalachian states. By far,
lime is the predominant alkali used by the industry. In
addition to the common industry practice of using the
conventional lime system, there are several processes in the
pilot or demonstration phase for treating acid mine drainage
that include: limestone-lime treatment, reverse osmosis and
neutrolosis, ion exchange methods, and chemical softening.
Conventional Neutralization
-------
Acid or ferruginous mine drainage is most often treated by a
method that can be called the "conventional lime
neutralization system," utilizing hydrated lime or quick
lime. Other alkalis available and used at some plants
include limestone, soda ash and caustic soda. Treatment
plants usually have facilities for 1) flow equalization, 2)
acidity neutralization, 3) ferrous iron oxidation,, and 1)
solids removal. From plant to plant there can be variations
to this basic system which may exclude the equalization or
oxidation steps, or include methods to enhance solids
removal and minimize sludge volume. In addition, where
neutralization is not required, excessive concentrations of
iron and suspended solids can be reduced by aeration and
sedimentation. A description of the facilities employed in
the conventional lime neutralization process follows.
I • FjLoy Sgual jzation . Surface holding ponds or
underground sumps are frequently employed to equalize
the flow and quality of the acid mine drainage before
treatment. These facilities usually have the capacity
to provide for one or more day's storage in case of
treatment plant shut down. Surface ponds also provide a
constant head for gravity flow through the treatment
plant.
2* Acidity Neutralization. Mineral acidity in raw
mine drainage is neutralized with one of the above
mentioned alkalis. In addition to neutralizing acidity,
these alkalis also enhance the removal of iron,
manganese, and other soluble metals through the
formation of their insoluble hydroxides,
i
3- Iron Oxidation. When iron is present in raw mine
drainage in the ferrous form, usual practice is to
provide aeration facilities for oxidation to the ferric
state. Ferric iron is more insoluble than the ferrous
form at lower pH's, thus the reasoning for the
oxidation step. Some companies however, remove iron as
ferrous hydroxide as the resulting sludge is more dense,
producing less volume for disposal.
*• Solids Removal . As a result of the chemical
treatment process, suspended solids are formed. Both
earthen settling basins and mechanical clarifiers are
used for removal of these suspended solids. Earthen
impoundments with detentions of from one day to as much
as several months are most often used. The detentions
provided usually are more dependent on the sludge
storage capacity desired than for suspended solids
removal.
-------
The manner by which coal operators have approached the
design and construction of conventional neutralization
treatment facilities varies from somewhat sophisticated
plants to simple or rather crude installations. Performance
of many of these facilities varied significantly, but this
was due to operational problems rather than waste treatment
difficulties. Descriptions of several of these treatment
plant installations are included here to provide a more
complete explanation of the conventional neutralization
treatment technology currently in use.
The following mines using conventional naturalization were
visited.
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Mine code A-l
Mine Al is a deep mine located in southwestern Pennsylvania
and operating in the Pittsburgh (bituminous) coal seam.
coal is mined at the rate of 2,963 KKG (3,267 tons) per
shift. Based on the 1973 production of 1,846,652 KKG
(2,036,000 tons), the estimated life of the present reserves
is 42 years.
Treatment is provided for discharge point Al-1 by a
conventional lime neutralization plant that was constructed
in 1968. Raw water is pumped on demand by a 75.7 liter per
second (1,200 gallon per minute) pump to an 11,355 cubic
meter (3 million gallon) holding pond. The water is then
neutralized at the average rate of 1,586 cubic meters per
day (.419 million gallons per day) by mixing with 0.608 KKG
per day (0.67 tons per day) of a hydrated lime slurry. The
lime neutralization process operates one hour on and one
hour off throughout the day. The chemically treated water
flows to a 253,595 liter (67,000 gallons) mechanical
aeration tank, then to an 18.9 meter (62 ft) diameter
thickener before discharging to the adjacent surface stream.
The thickener provides a detention of 16 hours at the
average flow rate. The sludge resulting from the chemical
treatment is removed from the thickener and is pumped to a
30,280 cubic meter (8 million gallon) sludge holding basin.
A schematic diagram of this treatment plant appears in
Figure 20. Average raw and effluent analyses of samples
collected at this treatment plant are presented in Table 7.
100
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FIGUKE 20
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE A-l
22.71 liters per second
RAW HATER
HOLDING POND
FLASH MIX
TAHK
AERATION
TANK
1
LIME
SLURRY
CLARIFIER
EFFLUENT TO CREEK
17.98 liters
per second
T
I 4.73 liters per second
SLUDGE
POND
-------
TABLE 7
Analytical Data - Mine Code A-l
Constituent
Raw Mine Drainage
Point Al-1
Average Quality*
pH 2.9
Alkalinity 0
Specific Conductance 5152
Solids, total dissolved 4662
Solids, suspended 133
Hardness 1093
Iron, total 212
Iron, dissolved 185
Manganese, total 9.17
Aluminum, total 69.3
Zinc, total 0.93
Nickel, total 0.66
Strontium, total 9.10
Sul fates 3043
Chloride 73.7
Fluoride 2,20
Ammonia 9.3
Chromium, total 0.03
Copper, total 0,18
Treated Mine Drainage
Point Al-2
AverageQuality**
7.2
31
5993
4946
94
1710
1.44
0.28
1.09
1.09
0.05
0.01
9.40
2926
124
2.45
2.54
0.02
0.01
*Based on three consecutive 24 hour composite samples.
**Based on two consecutive 24 hour composite samples.
All results expressed in mg/1 except for pH
conductance.
and specific
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, mercury, molybdenum, lead
and selenium, but these were not detected in significant
concentrations .
102
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Mine Code A-2
Mine A2 is a deep mine located in southwestern Pennsylvania
operating in the Pittsburgh (bituminous) coal seam. Coal is
mined at the rate of 2,872 KKG (3,167 tons) per shift.
Based on the 1973 production of 1,567,300 KKG (1,729,000
tons), the estimated life of the present reserves is eight
years. The mine presently has four (4) points of
dewatering, all of which are pumped. Two of these
discharges require treatment. The analytical quality of
treated discharge A-2 is shown in Table 9.
Treatment is provided for discharge point A2-1 by a
conventional lime neutralization plant that was constructed
in 1968, Raw drainage is pumped through a bore hole by a
78.88 liter per second (1,250 gallon per minute) pump
directly to the flash mix tank where it is neutralized by
mixing with 6.35 KKG per day (7 tons per day) of hydrated
lime as a slurry. The chemically treated water flows to a
pre-settling tank and then to a 246,000 liter (65,000
gallon) mechanical aeration tank. The sludge pre-settling
tank requires cleaning every 6 months. The aerated water is
discharged to a 3,030,000 liter (800,000 gallon) primary
settling pond which contains a continuous sludge removal
system. The overflow from this pond enters a 4,542 cubic
meter (1.2 million gallon) secondary settling pond before
discharging to the stream. ^
The sludge resulting from this treatment system is pumped
from the primary settling pond to a 1,022,000 liter (270,000
gallon) holding pond, then pumped directly to a large
dewatering basin encompassing approximately 4.05 hectares
(10 acres). The overflow from this basin is also discharged
to the stream.
A diagram of the treatment sequence is shown in Figure 21.
The analytical data for the treatment facility is shown in
Table 8.
103
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FIGURE 21
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MIME-A-2
»
79.85 liters per second
LIME
SLURRY
PLASH MIX
TANK
AERATION
TANK
*i
. PRIMARY
SETTLING
POND
1
SECONDARY
SETTLING
POND
EFFLUENT TO
CRSElK *
60.56 liters
per second
t
OVERFLOW
TO CREEK
SLUDGE
POND
~ 18.29 liters
*"per second
SLUDGE
TANK
-------
Table 8
Analytical Data - Mine Code A-2
Constituent
Raw Mine Drainage
Point A2-1
Average Quality*..
pH 3.1
Alkalinity 0
Specific Conductance 7103
Solids, total dissolved . 6814
Solids, suspended 59
Hardness 1627
Iron, total 276
Iron, dissolved 276
Manganese, total 11.5
Aluminum, total 58
Zinc, total 1.31
Nickel, total 1.29
Strontium, total 3.47
Sulfates 4031
Chloride 168
Fluoride 1.19
Ammonia 41,7
Copper, total 0.12
Treated Mine Drainage
Point A2-2
Average Quality*
8.4
52
6007
6053
115
2113
1.68
0.04
0.78
0.10
0.02
0.01
5.54
3262
298
1.62
4.05
0.01
*Based on three consecutive 24 hour composite samples.
All results, expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, chromium, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
105
-------
Ming Code A-3
Mine A-3 is the same mine referred to in Mine Code A-2.
Discharge A-3 is the second treated discharge from the mine.
The analytical data for this treatment plant is shown in
Table 9,
The treatment facility for discharge point A3-1 includes
lime neutralization followed by a baffled 7,9i»9 cubic meter
(2.1 million gallon) settling pond. This plant experienced
better settling of the ferrous sludge than the ferric; thus
aeration was eliminated. This plant, constructed in 1969,
treats 102.5 liters per second (1,625 gallons per minute) of
raw water using 5.1 KKG (6 tons) of hydrated lime each day.
Sludge removed daily from the settling pond is pumped to one
of two 7,9^9 cubic meter (2.1 million gallon) ponds. The
settled sludge is concentrated with any overflow discharged
to the stream. Final disposal of the concentrated sludge is
through a bore hole to an abandoned portion of the mine. A
diagram of the treatment sequence is shown in Figure 22,
106
-------
FIGURE22
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE A-3
102.51 liters per second
LIME
SLURRY
FLASH MIX
TANK
SETTLING
POND
EFFLUENT TO CREEK
6 0.8-1
per second
SLUDGE TO UNDERGROUND
26.88 liters per second
SLUDGE
POND
OVERFLOW TO CREEK
14.82 liters
per second
-------
Table 9
analytical Data - Mine Cod© A-3
JRaw Mine Drainage Treated Mine Drainage
Point A3-1 Point A3-2
Constituent Average Quality* '• Average jMality**
pH 3.0 8.9
Alkalinity 0 16
Specific Conductance 3080 2910
Solids, total dissolved 2650 2538
Solids, suspended 73 26
Hardness 880 1120
Iron, total 164 0.35
Iron, dissolved 139 0.01
Manganese, total 3.83 0,07
Aluminum, total 7.9 0.10
2inct total 0.33 0.02
Hickel, total 0,34 0.01
Strontium, total 2.9 2.8
Sulfates 1323 1H32
Chloride 52 99
Fluoride 0.87 0.76
Ammonia 5.8
*Based on three consecutive 23 hour composite samples,
**Based on one 21* hour composite sample.
All results expressed in mg/1 except for pH and specific
conductance,
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead, and selenium, but these were not detected
in significant concentrations.
108
-------
Mine Code A-3
Mine A4 is a deep mine located in southwestern Pennsylvania
operating in the Pittsburgh (bituminous) coal seam. The
mine encompasses 6885 hectares (17,000 acres), of which
6,075 hectares (15,000 acres) remain. Coal is mined at the
rate of 887 KKG (978 tons) per shift with a recovery of
about 70 percent. Based on the 1973 production of 638,528
KKG (704,000 tons), the estimated life of the present
reserves is 67 years.
The mine presently has four (H) points of dewatering, two of
which are pumped to the surface and treated, the analytical
quality of the raw and treated discharge of one of these
points is shown in Table 10. Treatment consists of a
conventional lime neutralization plant that was constructed
in 1973. Raw water is pumped out of the mine at a rate of
105.13 liters per second (1,666 gallons per minute) for 15
hours per day. This drainage is neutralized at an average
rate of 5,451 cubic meters per day (1.44 mgd) by mixing it
with .907 KKG per day (1.0 ton per day) of dry hydrated lime
in the flash mix tank. Ferrous iron is oxidized by natural
aeration in a long trough as the drainage flows to a large
settling basin that has a capacity of 113,550 cubic meters
(30 million gallons). It is expected that the settling
basin has a sludge capacity for four more years before some
other means of disposal will become necessary.
A diagram Of the treatment sequence appears in Figure 23.
109
-------
FIGURE 23
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE A-4
39.43 liters per second
DRY
LIME
FLASH MIX
TANK
SETTLING
POND
EFFLUENT TO CREEK
39.43 liters per second
-------
Table 10
Analytical Data - Mine Code A-4
Constituent
Raw Mine Drainage Treated Mine Drainage
Point A4-1 Point A4-2
Average Quality* Average Quality**
pH 5.8
Alkalinity 81
Specific Conductance 10,268
Solids, total dissolved 8,774
Solids, suspended 397
Hardness 1,487
Iron, total 187
Iron, dissolved 63.7
Manganese, total , 8.13
Aluminum, total 36.4
Zinc, total 0.62
Nickel, total 0.36
Strontium, total 3.35
Sulfates 4,418
Chloride 1,940
Fluoride 0.86
Ammonia 3.19
Boron, total 0.30
Copper, total 0.06
8.0
291
8098
8368
19
1800
0.48
0.01
2.46
0.10
0.03
0.08
4.24
4001
1737
1.28
1.86
0.30
0.01
*Based on one grab sample and two consecutive 24 hour
composite samples.
**Based on three consecutive 24 hour composite samples.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, cadmium, chromium, mercury, molybdenum,
lead and selenium, but these were not detected in
significant concentrations.
Ill
-------
Mine Code B-2
Mine B2 is a large, deep mine located in southwestern
Pennsylvania operating in the Pittsburgh coal seam. The
mine encompasses an area of 2,633 hectares (6,500 acres) of
which 162 hectares (400 acres) remain. The (estimated life
is about ten years. Coal output is 635 KKG (700 tons) per
shift with a recovery of 70 percent. The production rate
for 1973 was 498,850 KKG (550,000 tons).
Raw mine drainage is collected at one central point
underground and is pumped to the surface at a rate of 176.7
liters per second (2,800 gallons per minute) . The
analytical quality of the raw and treated mine drainage is
shown in Table 11. The treatment provided for discharge
point B2-1 includes equalization, lime neutralization,
mechanical aeration, primary settling by a mechanical
clarifier and effluent polishing in a large 8,176 cabic
meters (2.2 million gallon) settling pond. Haw mine
drainage is pumped to the equalization pond at 15,261 cu
m/day and is neutralized with 19 KKG (21 tons) per day of
slaked lime slurry.
A diagram of this treatment sequence appears in Figure 24,
and shows capabilities of sludge recirculation; however, the
plant* s normal operation excludes this as sludge thickening
by recirculation was unsuccessful.
112
-------
FIGURE 24
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE B-2
176.63 liters per second
RAW WATER
HOLDING POND
LIME
SLURRY
AERATION
TANK
POLYMER
FEED
CLARIFIER
POLISHING
POND
I
I
| SLUDGE JTO ;
ABANDONED MINE
EFFLUENT TO
CREEK
151.4 liters
per second
-------
Table 11
Analytical Data - Mine Code B-2
Constituent
Raw Mine Drainage
Point B2-1
Average Quality*
pH 2.7
Alkalinity 0
Specific Conductance 51U5
Solids, total dissolved 6397
Solids, suspended 183
Hardness 1167
Iron, total 112
Iron, dissolved 95
Manganese, total 8.8
Aluminum, total 60
Zinc, total 1.8
Nickel, total 0.79
Strontium, total 1.5
Sulfates 1153
Chloride 9.2
Fluoride 1.05
Ammonia 35
Chromium, total 0.09
Copper, total 0.18
Treated Mine Drainage
Point B2-2
Average Quality* •
6.9
17
4080
21
1920
0.15
0.06
0.17
0.1
0.01
0.01
3.9
1882
17
1.11
2.9
0.01
0.01
*Based on three consecutive 21 hour composite samples.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, mercury, molybdenum, lead
and selenium, but these were not detected in significant
concentrations.
114
-------
Mine Code D-3
Mine D3 is a deep mine located in northern West Virginia
operating in the Pittsburgh (bituminous) coal seam. The
mine encompasses 2,680 hectares (6,618 acres), of which 405
hectares (1,000 acres) remain. Coal is mined at the rate of
907 KKG (1,000 tons) per shift with a recovery of about 55
percent. Based on the 1973 production of 671,963 KKG
(740,863 tons), the estimated life of the present reserves
is 10 years.
The analytical quality of the raw and treated mine drainage
is shown in Table 12. Treatment is provided for discharge
point D3-1 by a conventional lime neutralization plant that
was constructed in 1969. Raw mine drainage is pumped to an
1,893,000 liter (500,000 gallon) holding pond at a rate of
16.U liters per second (260 gallons per minute), and is then
neutralized by mixing with 2.59 KKG per day (2.86 tons per
day) of a hydrated lime slurry. The chemically treated
water is discharged to a 3,603,320 liter (95,200 gallon)
mechanical aeration tank before flowing to two 5,678 cubic
meter (1.5 million gallon) settling ponds operated in
series.
About once every three months, sludge is pumped from the
primary settling basin to the preparation plant refuse
impoundment. A diagram of the treatment sequence appears in
Figure 25.
115
-------
FIGURE 25
SCHEMATIC DIAGRAMFOR TREATMENT FACILITIES AT MINE D-3
18.93 liters per second
RAW WATER
HOLDING POND
FLASH MIX
TANK
LIME
SLURRY
SLUDGE TO
REFUSE PILE
T
AERATION
TANK
PRIMARY
SETTLING BASIN
SECONDARY
SETTLING BASIN
EFFLUENT TO
CREEK
»
16.40 liters
per second
-------
Table 12
Analytical Data - Mine Code p-3
Constituent
Raw Mine Drainage
Point D3-1
Average Quality*
pH 5.9
Alkalinity 22
Specific Conductance 2678
Solids, total dissolved 2319
Solids, suspended 287
Hardness 890
Iron, total 123
Iron, dissolved 55
Manganese, total 3.2
Aluminum, total 15.5
Zinc, total 0.44
Nickel, total 0.39
Strontium, total 2.3
Sulfates 1394
Chloride 28
Fluoride 0.54
Ammonia 3.2
Treated Mine Drainage
Point D3-2
Aver a
-------
Mine code P-H
Mine Dtt is a deep mine located in northern west Virginia
operating in the Pittsburgh (bituminous) coal seam. The
mine encompasses 7081 hectares (17,485 acres) of which
-------
FIGURE 26
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE D-4
4 liters per second
LIME
SLURRY
FLASH MIX
TANK
AERATION
TANK
SETTLING
POND
EFFLUENT TO CREEK
16.4 liters per second
-------
Table 13
Analytical Data - Mine p-4
Acid and Treated Mine Drainage
Constituent
Acid Mine Drainage
Point Dit-1
Average Quality*
pH 2.6
Alkalinity 0
Specific Conductance 11,780
Solids, total dissolved 15,359
Solids, suspended 621
Hardness 1,960
Iron, total 980
Iron, dissolved 970
Manganese, total 21
Aluminum, total 17.4
Zinc, total 7.2
Nickel, total 2.6
Strontium, total 2.6
Sulfates 7,508
Chloride 115
Fluoride 0.22
Ammonia
Treated Mine Drainage
Point OH-2
Average Quality*
6.8
18
6935
6850
192
1580
1.6
0.08
0.9
1.1
0.06
0.01
1.9
3009
1.82
1,2
*Based on three consecutive 24 hour composite samples.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
120
-------
Mine Code E-6
Mine E6 is a deep mine located in central Pennsylvania
operating in the Miller "B" or Lower Kittanning (bituminous)
coal seam. The mine encompasses 2,273 hectares (5,612
acres), of which 358 hectares (884 acres) remain. Coal is
mined at the rate of 735 KKG (810 tons) per shift with a
recovery of about 70 percent. Based on the 1973 production
of 496,143 KKG (517,045 tons), the estimated life of the
present reserve is eight years.
The analytical quality of the two combined and equalized
mine discharge points is shown in Table 14. Treatment is
provided for these combined discharges by a conventional
lime neutralization plant that was constructed in 1969.
Acid mine water is pumped on demand from two sections of the
mine at a rate of 113.6 liters per second (1,800 gallons per
minute) to an 11,355 cubic meter (3 million gallon) holding
pond. The drainage is then neutralized at the average rate
of 4040 cubic meters per day (1.067 million gallons per day)
by mixing with 5.44 KKG per day (6.0 tons per day) of a
hydrated lime slurry. The chemically treated mine drainage
flow to a 94,625 liter (25,000 gallon) mechanical aeration
tank. From here it then splits into two streams; one flows
to a 24.4 meter (80 fee diameter clarifier, and the other to
a 3786 cubic meter (1 million gallon) pond for settling of
the solids. The clarified drainage from both settling
facilities is then discharged directly to the nearby surface
stream. Sludge removed from the clarifier is pumped into
old mine workings through a bore hole. It should be noted
that the settling pond effluent quality was below average
due to short circuiting caused by sludge accumulation.
A diagram of the treatment sequence appears in Figure 27,
while analytical data for this facility is presented in
Table 1U.
121
-------
FIGURE 27
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE E-6
52.57 liters per second
RAW WATER
HOLDING POND
FLASH MIX
TANK
AERATION
TANK
LIME
SLURRY
SETTLING
POND
EFFLUENT TO CREEK
17.41 liters per second
x 5.8
t ~
SLUDGE TO BOREHOLE
5.83 liters per second
CLARIFIER
EFFLUENT TO CREEK
29.33 liters per second
-------
Table 14
Analytical Data - Mine Code E-6
Constituent
Raw Mine Drainage
Point E6-1
Average Quality*
Treated Mine Drainage
Points E6-2, E6-3
Average Quality**
pH 2.7
Alkalinity 0
Specific Conductance 5105
Solids, total dissolved 6337
Solids, suspended 357
Hardness 1740
Iron, total 760a
Iron, dissolved 760
Manganese, total 7.0a
Aluminum, total 66.0a
Zinc, total 2.3a
Nickel, total 0.66a
Strontium, total 0.59a
Sulfates 3478
Chloride 15
Fluoride 1.67
Ammonia 7.Oa
Chromium, total 0.05a
Thickener
8.2
29
3625
4240
11
2590
1.34
0.26
0.55
0.75
0.02
0.05
1.60
2141
13
0.94
5.6
0.07
Pond
4.0
5
3688
4395
258
2520
18.4
12.9
1.7
0.59
0.10
0.14
1.75
2168
11.5
0.64
4.2b
0.01
*Based on two consecutive daily grab samples.
**Based on two consecutive 24-hour composite samples.
a. Based on one grab sample.
b. Based on one 24-hour composite sample. All results
expressed in mg/1 except for pH and specific conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
123
-------
Ming code F^2
Mine P2 is a deep mine located in central Pennsylvania
operating in the Lower Kittanning (bituminous) coal seam.
The mine encompasses 2,289 hectares (5,655 acres), and coal
is mined at the rate of 1,133 KKG (1,21*9 tons) per shift
with a recovery of about 70 percent. Based on the 1973
production of 779,280 KKG (859,184 tons), the estimated life
of the present reserves is 33 years.
Treatment is provided for this discharge point by a
conventional lime neutralization plant that was constructed
in 1967. Raw water is pumped on demand to a 2,120,000 liter
(560,000 gallon) holding pond. Drainage is then neutralized
at the average rate of 3,119 cubic meters per day (.82*
million gallons per day) by mixing with 4.44 KKG per day
(4.9 tons per day) of a hydrated lime slurry. The
chemically treated water is naturally aerated in a short
baffled trough then discharged into one of three settling
basins, each having capacities of 7,192 cubic meters (1.9
million gallons), Each basin is used until a substantial
amount of sludge accumulates, then the flow is directed to
one of the others while the sludge is pumped to one of three
1,115 square meter (12,000 square fee sludge drying ponds.
Additional sludge ponds are to be constructed as needed.
Any overflow from these flows directly to the stream.
A diagram of the treatment sequence appears in Figure 28,
and analytical data is presented in Table 15.
124
-------
FIGURED28^
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE F-2
3_6.._0_8_ liters per second
RAW WATER
HOLDING POND
FLASH MIX
TANK
LIME
SLURRY
SETTLING
POND
SETTLING
POND
SETTLING
POND
EFFLUENT TO CREEK^
,08 liters per second
SLUDGE
POND
SLUDGE
POND
SLUDGE
POND
EFFLUENT TO CREEK
-------
Table 15
Analytical Data - Mine Code F-2
Raw Mine Drainage Treated Mine Drainage
Point F2-l,3 Point F2-H
Constituent Average Quality* Average Quality**
pH 2.5 7.9
Alkalinity 0 30
Specific Conductance 4465 3400
Solids, total dissolved 5433 3636
Solids, suspended 45 8
Hardness 1320 2640
Iron, total 380 1.0
Iron, dissolved 370 0.02
Manganese, total 4.3 0.12
Aluminum, total 54 1.8
Zinc, total 5.4 0.08
Nickel, total 2.0 0.08
Strontium, total 0.76 2.4
Sulfates 2942 2324
Chloride 17 28
Fluoride 0.54 0.58
Ammonia 14.9 6,9
Chromium, total 0.05 0.03
copper, total 0.67 0.01
*Based on two consecutive 24 hour composite samples.
**Based on one 24 hour composite sample.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, mercury, molybdenum, lead,
and selenium, but these were not detected in significant
concentrations.
126
-------
Mine Code K-6
Mine K6 represents a deep mine located in central
Pennsylvania operating in the Lower Kittanning (bituminous)
coal seam. The mine encompasses 24,098 hectares (59,500
acres), of which 9,477 hectares (23,400 acres) remain. Coal
is mined at the rate of 1,938 kkg (2,137 tons) per shift,
with a recovery of about 63 percent. Based on the 1973
production of 1,371,967 kkg (1,512,643 tons), the estimated
life of the present reserves is 60 years.
Treatment is provided for the raw mine drainage by a lime
neutralization plant that was constructed in 1971. Sludge
recycle is employed to reduce the final sludge volume
requiring disposal.
Raw mine drainage is pumped continuously from an underground
sump directly into a carbon dioxide sparging tank at a rate
of 233.5 liters per second (3,700 gallons per minute) during
the weekdays. Over the weekend the flow rate is increased
to 466.9 liters per second (7,400 gallons per minute). The
overflow from the sparging tank enters to a 1,021,950 liter
(27,000 gallon) aeration tank where it is neutralized with a
lime slurry conditioned with recycled sludge. The
chemically treated water then overflows to a 54.9 meter
(180 fee diameter clarifier. Sludge from the clarifier is
recycled back to the lime slurry mix tank at a rate of 31.55
liters per second (500 gallons per minute) while any excess
is pumped to an abandoned section of a deep mine.
A diagram of the treatment sequence appears in Figure 29,
and analytical data is presented in Table 16.
127
-------
FIGURE 29
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE K-6
298.4 liters per second
ro
CD
CARBON DIOXIDE
SPARGING TANK
1
•• ,,„„
r
REACTION
TANK
LIME
SLURRY
SLUDGE RECYCLE
31.54 liters per second
*" 1
1
1
.. t
CLARIFIER
EFFLUENT TO CREEK
247.68 liters per second
I
; SLUDGE TO BOREHOLE
19.18 liters per second
-------
Table 16
Analytical Data - Mine Code K-6
Constituent
Raw Mine Drainage
Point K6-1
Average Quality*
pH 2.9
Alkalinity 0
Specific Conductance 2361
Solids, total dissolved 2367
Solids, suspended 136
Hardness 560
Iron, total 87.8
Iron, dissolved 82.8
Manganese, total 3.15
Aluminum, total 15.3
Sine, total 0.62
Nickel, total 0.46
Strontium, total 0.26
Sulfates 1150
Chloride 12.8
Fluoride 0.44
Ammonia 11.6
Selenium, total 0.04
Treated Mine Drainage
Point K6-2
Average Quality**
7.9
51
2193
2292
5
910
1.7
0,05
0.25
0.70
0.02
0.02
0.67
985
18.5
0.53
2.15
0.08
WkEnd
7.5
96
2258
2222
17
970
7.1*
0.17
3.05
1.0
0.55
0.15
0.70
1100
16.5
0.36
3.0
0.06
*Based on four consecutive 21 hour .composite samples.
**Based on two consecutive 2U hour composite samples.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, and lead, but these were not detected in
significant concentrations.
129
-------
Mine Code K-7
Mine K7 is a deep mine located in central Pennsylvania
operating in the Lower Kittanning coal seam. The mine
totals 5,073 hectares (12,527 acres) of which 790 hectares
(1,950 acres) remain. Based on the 1973 production of
3*12,896 kkg (378,000 tons), the mines estimated life
expectancy is 32 years.
Raw mine drainage collected underground is pumped through a
bore hole to a 3,785 cubic meter (1 million gallon) holding
pond. The drainage is treated by lime neutralization at an
average flew of 332, >» liters per second (5,268 gallons per
minute). sludge recycle is employed to reduce the final
sludge volume requiring disposal. The holding pond overflow
proceeds to a 151,flOO liter (40,000 gallon) reaction tank
where it is neutralized with lime slurry conditioned with
recycled sludge. The lime usage is 13.6 kkg (15 tons) per
day. The neutralized drainage flows into a 57.9 meter (190
ft) diameter clarifier. Sludge from the clarifier is
recycled back to the lime slurry mix tank at a rate of 31.55
liters per second (500 gallons per minute) while any excess
is pumped to an abandoned section of deep mine.
A diagram of the treatment facility appears in Figure 30,
and analytical data appears in Table 17.
130
-------
FIGURE 30
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE K-7
328.6 liters persecond
RAW WATER
HOLDING POND
REACTION
TANK
LIME
SLURRY
SLUDGE RECYCLE
31.54 liters per second
CLARIFIER
EFFLUENT TO CREEK
=275 liters per second
I SLUDGE TO BOREHOLE
-------
Table 17
Analytical Data - Mine Code K-7
Constituent
Raw Mine Drainage
Point K7-1
Average Quality*
pH 2.5
Alkalinity 0
Specific Conductance 2338
Solids, total dissolved 4115
Solids, suspended 69
Hardness 815
Iron, total 802
Iron, dissolved 32
Manganese, total U.25
Aluminum, total 42
Zinc, total 2.0
Nickel, total 1.0
Strontium, total O.ft
Sulfates 1550
Chloride 5
Fluoride 0.38
Ammonia 15
copper, total 0.2
Treated Mine Drainage
Point K7-2
Average Quality*
8.8
35
2103
2837
10
1600
1.8
0.03
0.03
1.0
0,02
0.01
1.95
IftSO
10
0.61
a.3
0.01
*Based on two consecutive 24 hour composite samples.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, chromium, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
132
-------
Mine Code D-l
Mine Dl is a deep mine located in southwestern Pennsylvania
operating in the Pittsburgh (bituminous) coal seam. The
mine encompasses 4050 hectares (10,000 acres) of which 648
hectares (1,600 acres) remain. Coal is mined at the rate of
907 KKG (1,000 tons) per shift, with a recovery of about 78
percent. Based on the 1973 production of 604,733 KKG
(777,7110 tons), the estimated life of the present reserves
is 15 years.
The drainage from Mine Dl does not require neutralization.
Treatment is provided by an aeration/sedimentation process
that was constructed in 1968. The average flow of drainage
passing through the treatment system is 24,603 cubic meters
per day (6,5 million gallons per day). The mine discharge
water is pumped directly to a 2,668,000 liter (705,000
gallon) mechanical aeration tank. Following aeration, a
coagulant aid is added to promote settling. The overflow
from the aeration tank then flows into two 13,250 cubic
meter (3.5 million gallon) settling basins operating in
parallel, before being discharged. Each basin provides a
detention of eight hours at the average flow. Periodically
one of the two settling basins is taken out of operation
while the sludge is pumped to a nearby tailings pond for
final disposal. ;
A schematic diagram of the treatment plant appears in Figure
31. Average raw and effluent analyses of samples collected
at this treatment plant are presented in Table 18.
133
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FIGURE 31
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE D-l
233.9 liters per second
AERATION
TANK,
SETTLING
POND
^ SLUDGE• ^
, 1
SETTLING
POND
EFFLUENT TO CREE
—»
TAILINGS
POND
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Table 18
Analytical Data - Mine Code D-l
Raw Mine Drainage Treated Mine Drainage
Point Dl-1 Point D1-U
Constituent Average Quality* Average .Quality**.
pH 7.7 8.0
Alkalinity 243 607
Specific Conductance 4210 4168
Solids, total dissolved 3744 3134
Solids, suspended 668 164
Hardness 1133 500
Iron, total 69.3 4.37
Iron, dissolved 67.6 0.02
Manganese, total 4.19 1.93
Aluminum, total 0.10 0.10
Zinc, total 0.04 0.04
Nickel, total 0.01 0.01
Strontium, total 3.07 2.36
Sulfates 1726 1322
Chloride 258 340
Fluoride 0.68 0.80
Ammonia 6.0 1.76
*Based on three consecutive daily grab samples.
**Based on three consecutive 24-hour composite samples.
All results expressed in nvg/1 except for pH and specific
conductance,
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
135
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Mine code p-5
Mine D5 is a deep mine located in northern West Virginia
that operates in the Pittsburgh coal seam which is 3.465
meters (88 inches) thick. The exact size of the mine is
unknown but it»s estimated that the mineable coal will
remain for another 20 years1 life. The 1973 coal production
was 641,342 KKG (707,323 tons) but the mine was severely
damaged by a fire in January, 1974 and no coal has been
mined since this date. Projected estimated re-opening of
the mine is sometime in the first quarter of 1975.
The mine has one major point of dewatering pumped at a rate
of 22 liters per second (350 gallons per minute). The
analytical quality of the raw and treated mine drainage are
presented in Table 19. Treatment of the raw mine drainage
consists of sodium hydroxide neutralization, mechanical
aeration, and primary and secondary settling. The two
settling ponds operating in series have capacities of 15,140
cubic meters (4 million gallons) and 5,677 cubic meters (1.5
million gallons) respectively, which provides for a total
theoretical detention of eleven days.
Sludge handling involves cleaning of the primary settling
pond approximately once every three years with final
disposal atop a refuse pile. The treatment facility is
expected to last for the life of the mine. A diagram of
this treatment sequence is shown in Figure 32,
136
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FIGURE 32
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE D-5
22.08 liters per second
1
CAUSTIC
FEED
AERATION-SETTLING
POND
POLISHING
POND
EFFLUENT TO CREEK
22.08 liters per second
SLUDGE TO REFUSE PILE
-------
Table 19
Analytical Data - Mine Code D~5
Raw and Treated Mine Drainage
Constituent
Raw Mine Drainage
Point D5-1
Average Quality*
pH 6.35
Alkalinity 104
Specific conductance 6018
Solids, total dissolved 6348
Solids, suspended 345
Hardness 1420
Iron, total 140
Iron, dissolved 140
Manganese, total 16
Aluminum, total 5.5
Zinc, total 0,24
Nickel, total 0.01
Strontium, total 3.7
Sulfates 3217
Chloride 650
Fluoride 1.2
.Ammonia 7.6
Treated Mine Drainage
Point D5-2
AverageQuality*
7.7
162
6528
6314
24
1390
2.5
0.02
2.8
0.1
0.05
0.01
3.95
3414
625
1.49
3.3
*Based on three consecutive 24 hour composite samples.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and treated mine drainage samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
138
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Other treatment processes.evaluated for possible inclusion
in BPT, BAT, NSPS for acid or ferruginous mine drainage are:
Limestone-Lime Heutralization
Limestone treatment is claimed to have several advantages
over the use of lime; (ly it gives a higher density, lower
volume sludge, (2) it is more economical, (3) it is less
toxic and therefore easier to handle, and, (H) it eliminates
potential pollution by accidental overtreatment. Limestone
however, is rarely used because of two main disadvantages;
first, itfs relatively inefficient rate of reaction results
in lime being more economical and reliable. Secondly,
limestone is usually unable to produce pH's higher than 7.0
which are necessary for rapid ferrous iron oxidation and
precipitation of heavy metals such as aluminum, manganese,
zinc, and nickel.
In an effort to combine the advantages of both limestone and
lime, a combination neutralization process has been
developed to attain a more economical method of acid mine
drainage treatment. This process uses the same unit
operations as the conventional neutralization process with
the exception that the addition of neutralization chemicals
occurs in two stages. Since limestone is highly reactive at
low pH'sr it is added first to the acid mine drainage until
a pH of 5.0 to 5.5 is reached. Lime is then used to
increase the pH to the level desired. In this process, both
limestone and lime are used in their most efficient ranges
of reactivity. Utilization of limestone's lower cost
results in an overall cost reduction of the combination as
compared to either reagent alone. An improvement in sludge
characteristics has also been evidenced in this process.
The resultant sludge contains 6 to 8 percent solids as
compared to 1 to 2 percent solids in lime neutralization
sludge. Treated water quality by both the lime and
limestone-lime processes is comparable.
It is important to note that the combination treatment is
not economically advantageous on all mine waters. A lime to
limestone cost ratio of 1.8/1.0 is the break-even point for
treating acid mine drainage where an economic advantage
would not be achieved by using limestone-lime rather than
with lime alone. As this ratio increases, so does the cost
advantage of the combination limestone-lime treatment.
Reverse Osmosis and Neutrolosis Systems
The use of the reverse osmosis systems for the treatment of
acid mine drainage has been investigated in studies
139
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sponsored by the Environmental Protection Agency.
Recoveries of 50 percent to 75 percent of the feed water
rate have been obtained with most mine drainages tested.
Problems have resulted from membrane module fouling from
suspended matter in the feed water, and chemically from the
formation of calcium sulfate and iron compounds. Suspended
solids can be adequately removed by 20 micron filters;
however, chemical fouling problems usually necessitate lower
recovery rates with blending of the product and feed waters.
Reverse osmosis is not selective to the removal of specific
chemical compounds. The product water will be of low
dissolved solids, usually less than 100 mg/1, but it will
also have a low pH and may contain iron, manganese, and
other parameters in excess of allowable discharge levels.
This may necessitate additional product water treatment.
It is also important to consider the means for disposal of
the brine from a reverse osmosis system. While the volume
may be small, the brine will contain all of the constituents
rejected by the membranes at many times their original
concentrations in the feed water. The Environmental
Protection Agency developed the unique "Neutrolosis
Treatment Process" which incorporates a total package
concept for using reverse osmosis with proper disposal of
the brine and other waste products.
The Neutrolosis Process consists of the basic reverse
osmosis system and lime neutralization facilities for
chemical treatment of the brine. In this manner, many
constitutents such as; iron, manganese, aluminum, and other
metals will be almost totally removed by chemical
precipitation. Other parameters such as calcium, magnesium,
and sulfate will be reduced. The treated water from the
neutralization stage of the system is then recycled to the
R-O feed water stream. Thus, the total system produces only
good quality product water and a sludge.
Costs for treating acid mine drainage by reverse osmosis or
neutrolosis are not readily available. Estimated costs
therefore have been developed based on the application of
reverse osmosis in other fields. Published operating costs
of $0.079 to $0.106 per cubic meter ($0.30 to $0.40 per
thousand gallons) are common for treating brackish waters at
feed recoveries of about 90 percent. These costs are all-
inclusive for manpower, chemicals, power, depreciation, etc.
Since feed recoveries of 90 percent cannot be expected when
treating acid mine drainage additional R-O equipment will be
needed to produce the same volume of product water.
140
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Therefore, operating costs have been increased by 100
percent for estimating purposes.
In addition to the cost of operation of a reverse osmosis
system is the cost for the neutralization facilities for the
brine stream. Operating costs of from $.027 to $.106 per
cubic meter ($0.11 to $0.40 per thousand gallons) were
obtained for the plants discussed in Section VIII. An
operating cost of $.079 per cubic meter ($0.30 per thousand
gallons) will be used here for a low volume-high acidity
drainage. Based on these estimates, total operating costs
of approximately $.27 per cubic meter ($1.10 per thousand
gallons) should be considered.
Lime-Soda Softening
The precipitation method for softening water takes advantage
of the low solubilities of calcium and magnesium compounds
to remove these hardness causing cations from solution.
Calcium is precipitated as calcium carbonate by increasing
the carbonate concentration in a water. Similarly,
magnesium is precipitated by increasing the hydroxide
concentration. While many chemicals can be used to produce
the excess carbonate or hydroxide ion concentrations to
bring about these precipitations, economics has dictated
that the best materials are lime and soda ash.
For applying this treatment to mine drainage or waters
affected by mine drainage, the first four unit processes are
the same as for conventional lime neutralization; that is ,
raw drainage equalization, acidity neutralization with lime
(to pH 10.8), iron oxidation, and solids removal. The
additional unit processes required to complete lime-soda ash
softening are described herein. It is important to point
out that this treatment process does not greatly change the
total dissolved solids of the water; it only replaces the
calcium ion with sodium. Other compounds such as sulfate
are also unaffected.
Softening. Primary effluent water at pH 10.8 will contain
the original non-carbonate calcium hardness, the non-
carbonate calcium hardness formed during lime treatment, the
calcium hardness due to excess lime addition, and some
residual magnesium hardness. Soda ash is then added to
remove nearly all of the calcium hardness by precipitation
as the insoluble carbonate.
Solids Removal. Following soda ash addition, sedimentation
is required to remove the suspended matter formed, which
consists mostly of calcium carbonate.
141
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Recarbonation. The softened effluent is usually
supersaturated with calcium carbonate and carbon dioxide is
added to convert some of the carbonate to bicarbonate. This
lowers the carbonate concentration and pH to a level at
which no further precipitation of calcium carbonate will
occur once the water leaves the plant.
The Pennsylvania Department of Environmental Resources has
constructed a water treatment plant near the city of Altoona
that employs the lime-Soda Process to chemically soften a
water supply affected by acid mine drainage. The plant only
recently was placed in operation and as yet the treated
water is not being discharged into the city's water supply.
Ion Exchange Process
Ion exchange in water treatment is defined as the reversible
interchange of ions between a solid medium and the aqueous
solution. To be effective, the solid ion exchange medium
must contain ions of its own, be insoluble in water, and
have a porous structure for the free passage of water
molecules. Within the solution and the ion exchange medium,
a charge balance or electroneutrality must be maintained;
i.e., the number of charges, not the number of ions, must
stay constant. Ion exchange materials usually have a
preference for multivalent ions; therefore, they tend to
exchange their monovalent ions. This reaction can be
reversed by increasing the concentration of monovalent ions.
Thus, a means exists to regenerate the ion exchange material
once its capacity to exchange ions has been depleted.
In the present day technology of ion exchange, the resins
available can be classified as strong-acid cation, weak-acid
cation, strong-base anion, and weak-base anion types.
Combinations of the available resins have been used in
systems for treatment of different waters for specific
purposes. The applications of these systems to the
treatment of mine drainage has been studied mainly to
produce potable water where a reduction in the total
dissolved solids is required. Processes developed include
the Sul-bisul Process and the Modified Desal Process.
Sul-biSul process- This process employs a two or three bed
system. Cations are removed by a strong acid resin in the
hydrogen form, or by a combination of weak acid and strong
acid resins. Following this, the effluent water is
decarbonated to remove carbon dioxide formed in the process.
Then a strong-base anion resin operates in the sulfate to
bisulfate cycle and removes both sulfate and hydrogen ions
during the exchange reaction. The effluent is filtered
142
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according to Public Health Regulations before use as a
potable water.
Regeneration of the cation exchange bed is accomplished with
either hydrochloric or sulfuric acid. In the regeneration
of the anion bedr bisulfate ions are converted back to the
sulfate form by the feed water. The addition of lime slurry
to the regenerant will speed this part of the process.
The Sul-biSul Process can be used to demineralize brackish
water containing predominantly sulfate anions, It can be
applied to waters with a dissolved solids content of up to
3,000 mg/1. The raw water should have an alkalinity content
of about 10 percent of the total anion content with a
sulfate to chloride anion ratio of at least ten to one.
This water must be sufficiently alkaline and abundant so
that it may be used as a regenerant and then discharged to
the stream. If the raw water cannot be used as the anion
bed regenerant, other alkalis must be employed. When this
is necessary, all tests have indicated that there is a
negative net production of water.
A water treatment plant using this process has been
constructed at Smith Township, Pennsylvania; however,
operational problems with the continuous ion exchange
regeneration equipment have prevented its use.
Modified Desal Process. This process uses a weak base anion
resin in the bicarbonate form to replace sulfate or other
anions, as *well as free mineral acidity. The solution of
metal bicarJoonates is aerated to oxidize ferrous iron to the
ferric form and to purge the carbon dioxide gas. The
effluent is then treated with lime to precipitate metal
hydroxides, settled to remove suspended solids, then
filtered if to be used as a potable supply.
Ammonia is used as the alkaline regenerant to displace
sulfate from the exhausted resin. Lime is used to
precipitate calcium sulfate from the regeneration wastes and
to release the ammonia regenerant for reuse. In this way,
ammonia is recycled in the process. It is possible to
recover the carbon dioxide and lime used in this process by
roasting lime sludge wastes in a kiln. In this manner, the
principal chemicals used in the process can be recovered to
some extent, with only potable water, and an iron hydroxide,
calcium sulfate sludge being the resultant products.
The Modified Desal Process is not limited by total dissolved
solids or pH levels; however, large quantities of carbon
dioxide are required to achieve good resin utilization for
143
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high total dissolved solids or alkaline feed waters. The
process is limited in application to waters containing less
than 2,200 parts per million of sulfate. Another limitation
is that mine waters containing iron in the ferric form may
cause fouling of the anion bed because of precipitation of
ferric hydroxide.
A demonstration plant for treatment of acid mine drainage by
the Modified Desal process has been constructed by the
Pennsylvania Department of Environmental Resources at Hawk
Run near Philipsburg, Pennsylvania. The purpose of this
plant is to provide a drinking water supply. Operating data
for this plant is not available.
Alakline Mine Drainage
Alkaline mine drainage can be encountered in any coal mine
region, but is found infrequently in the northern
Appalachian states as discussed in "Acid or Ferruginous Mine
Drainage.11
Treatment of alkaline mine drainage results in one or two
classes of effluent: discharge effluent or sediment-bearing
effluent.
Discharge Effluent
Mine drainage falling into this classification is alkaline
mine drainage containing low concentrations of metals such
as iron, manganese, or aluminum. In most instances, this
type of effluent meets the local state requirements, for
direct discharge without further treatment.
Some states require that discharges in this type flow
through a settling basin which is to serve for the removal
of any suspended solids and to equalize the flow and quality
of the drainage before discharge into the receiving stream.
There are no apparent benefits for such settling basins
other than to provide for the equalization of effluent
quality if such a variation does occur. One disadvantage
was noted at Mines J2 and J3 where several basins were
observed to have a profound algae growth in the summer
months. This apparently contributed to a higher suspended
solids1 concentration in Mine J-2's effluent than was
present in the raw mine drainage.
Although these settling basins did not effect a removal of
suspended solids, they did provide sufficient natural
aeration to reduce the dissolved iron concentrations, as
144
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noted at Mine F8« Case histories for the mine codes
referenced in this section follow.
145
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Mine Code J-2
Mine J2 is a surface mine located in eastern Kentucky
operating in the Hance (bituminous) coal seam. The mine
encompasses approximately 364.5 hectares (900 acres).
Production for 1973 was 1,507,936 KKG (1,662,553 tons).
The analytical quality of the waste water resulting from
stripping operations is shown in Table 20. This drainage
flows directly to a 26,500 cubic meter (7 million gallon)
pond, constructed in 1970, for treatment by sedimentation
only. The effluent from this basin then discharges to the
nearby surface stream. Every nine months the settling basin
is cleaned by dredging the sludge and trucking it to a
nearby landfill.
During the sampling period significant algae growth was
observed in the pond, probably causing the suspended solids
increase evidenced in Table 20. A diagram of the treatment
sequence appears in Figure 33.
146
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FIGURE 33
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE J-2
*-
•vl
COLLECTION PIT
SURFACE RUNOFF
SETTLING
POND
EFFLUENT TO CREEK
SLUDGE TO LANDFIL
>FILL
-------
Table 20
Analytical Data - Mine Code J-2
Constituent
pH
Alkalinity
Specific Conductance
Solids,, total dissolved
Solids, suspended
Hardness
Iron, total
Iron, dissolved
Manganese, total
Aluminum, total
Zinc, total
Nickel, total
Strontium, total
Sulfates
Chloride
Fluoride
Ammonia
Raw Mine Drainage
Point J2-1
Average Quality
8.2
136
1600
1558
12
820
0.18
0.18
0.19
0.10
0.03
0.07
0.15
664
3.7
0.24
0.3
Discharge Effluent
Point J2-2
Averacre Quality
8.2
138
1630
1610
26
800
0.11
0.01
0.19
0.10
0.01
0.06
0.15
722
3.6
0.24
0.2
All average qualities based on one grab sample.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were jinalyzed for both
total and dissolved concentrations. 'Significant differences
were not measured except where otherwise reported.
The raw and discharge effluent samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
148
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Mine Code J-3
Mine J3 is a ' surface mine located in eastern Kentucky
operating in the Red Springs (bituminous) coal seam. The
mine encompasses approximately 24.3 hectares (60 acres)»
Production for 1973 was 111,251 KKS (155,734 tons).
The analytical quality of the waste water resulting front
stripping operations is shown in Table 21. The majority of
this drainage accumulates in an open pit, before flowing to
three settling basins operated in series. These basins were
constructed in April, 1974 and each has a capacity of
757,000 liters (200,000 gallons).' The effluent from the
final settling basin discharges to the nearby surface
stream. Sludge build-up in these ponds has not yet been a
problem.
Significant algae growth in the pond apparently retarded any
possible suspended solids reduction as evidenced in Table
21. A schematic diagram of the treatment plant is shown in
Figure 31.
149
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FIGURE 34
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE J-3
H
Ul
Q
SURFACE
RUNOFF
SETTLING
POND
SETTLING
POND
SETTLING
POND
EFFLUENT TO
CREEK
-------
Table 21
Analytical Data - Mine J-3
Raw Mine Drainage Discharge Effluent
Point J3-1 Point J3-2
Constituent Average Quality Average Quality
pH 8.1 7.8
Alkalinity 66 64
Specific Conductance 360 360
Solids, total dissolved 300 298
Solids, suspended 16 16
Hardness 19U 186
Iron, total 0.14 0.12
Iron, dissolved 0.09 0.01
Manganese, total 0.10 0.13
Aluminum, total 0.10 0.10
Zinc, total 0.01 0.01
Nickel, total 0.01 0.01
Strontium, total 0.03 0.03
Sulfates 99 93
Chloride 2.3 3.1
Fluoride 0.26 0.15
Ammonia 0.42 O.U7
All average qualities based on one grab sample.
All results expressed in rog/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and discharge effluent samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
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Mine Code F-8
Mine F8 is a deep mine located in central Pennsylvania
operating in both the Lower Freeport and Lower Kittanning
coal seams. Coal production for 1973 was 1,011,293 KKG
(1,114,987 tons}.
Treatment is provided for the mine water by sedimentation
through the use of two settling basins operated in series
that were constructed in 1970. Each basin has a capacity of
42,t\68 cubic meters (1.12 million gallons). The average
flow through the system is 6,170 cubic meters per day (1.63
million gallons per day) resulting in a total detention of
1.37 days. To date, it has not been necessary to remove
sludge from the settling ponds.
It is important to note that although no significant
suspended solids reduction occurred, most of the soluble
ferrous iron in the water was oxidized and settled as the
insoluble ferric form through natural aeration in the
settling ponds. This resulted in meeting the State's
discharge requirements for dissolved iron (0.5 rog/1) and
also lowering the total iron content of the water by
precipitation as ferric hydroxide. Analytical data for
these settling ponds is presented in Table 22, while a
diagram of the treatment sequence is presented in Figure 35.
152
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FIGURE 35
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE F-8
H
<-n
U>
71.28 liters
per second ^
SETTLING
POND
.. k^
SETTLING
POND
EFFLUENT TO CREEK
71.28 liters per secon^
-------
Table 22
Analytical Data - Mine F-8
Raw Mine Drainage Treated Mine Drainage
Point F8-1 Point F8-3
Constituent Average Qua.li.-ty Average Quality
pH 8.1 8.2
Alkalinity 28ft 27ft
Specific Conductance 1215 1195
Solids, total dissolved 872 858
Solids, suspended 18 14
Hardness 112 116
Iron, total 5.0 2.6
Iron, dissolved 1.5 0.0ft
Manganese, total 0.16 0.12
Aluminum, total 0.11 0.10
Zinc, total 0.01 0,006
Nickel, total 0,01 0.01
Strontium, total 0,50 0*57
Sulfates 364 298
chloride 8.4 7.4
Fluoride 0.50 0.18
Ammonia 1.7 2.0
Ferrous Iron 1.9 0-37
All average qualities based on one grab sample.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations, significant differences
were not measured except where otherwise reported.
The raw and treated drainage samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
154
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Se_diment-Bearin
-------
Mine Code p-ja
Mine D6 is a deep mine located in southwestern Pennsylvania
operating in the Pittsburgh (bituminous) coal seam, coal
production for 1973 was 1,896,015 KKQ (2,090,425 tons).
Mine water is pumped to the surface at an average rate of
4,920.5 cubic meters per day (1.3 million gallons per day)
and discharged into two settling basins operating in series.
The first basin has a capacity of 11,357 cubic meters (3
million gallons) and the second basin 946,425 cubic meters
(250 million gallons). The total detention for the two
basins is 195 days. The overflow from the larger basin
discharges to the nearby surface stream.
The settling basins appear to provide very good removals of
suspended solids. Analytical data for the treatment
facility is presented in Table 23, and a diagram of the
treatment sequence is shown in Figure 36.
156
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FIGURE 36
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MIKE D-6
LSI
56.69 liters
per second ^
SETTLING
POND
K.
SETTLING
POND
EFFLUENT TO CREEK
56.59 liters per second
-------
Table 23
Analytical Data - Mine Code D-6
Raw Mine Drainage
Point D6-1
pH 8.2
Alkalinity 705
Specific Conductance 3300
Solids, total dissolved 2191
Solids, suspended 244
Hardness 146
Iron, total 0.28
Iron, dissolved 0.10
Manqanesa, total 0.04
Aluminum, total 0.10
Zinc, total 0.03
Nickel, total 0.01
Strontium, total 1.35
Sulfates 635
Chloride 480
Fluoride 1.54
Ammonia 0.28
Sediment-Bearing Effluent
Point D6-3
8.6
645
3160
2128
22
85
0.16
0.01
0.04
0.10
0.03
0.01
0.87
506
520
1.41
0.59
*Based on two consecutive daily grab samples.
**Based on two consecutive 24-hour composite samples.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and sediment-bearing samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
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Mine Code N-6
Mine N6 is a surface mine located in southwestern
Pennsylvania operating in the Lower Ereeport (bituminous)
coal seam. The mine encompasses approximately 20.2 hectares
(55 acres) with practically all of the area remaining. No
coal was mined in 1973.
The analytical quality of the waste water is shown in Table
2ft. This water flows into a collection sump and is then
pumped into an 852,000 liter (225,000 gallon) settling
basin. The overflow from this first pond flows to a second
850 cubic meter pond, then discharges to the nearby surface
stream, h schematic diagram of this treatment plant appears
in Figure 37.
159
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FIGURE 37
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE N-6
SURFACE
RUNOFF ^
— P
COLLECTION
PIT
i
W'
SETTLING
PIT
SETTLING
PIT
EFFLUENT TO CREEK
— ... .. .. .p.
-------
Table 24
Analytical Data - Mine N-6
Raw Mine Drainage Sediment-Bearing Effluent
Point N6-1 Point N6-2
Constituent Average Quality Average Quality
pH 7.7 7.8
Alkalinity 66 78
Specific Conductance 355 725
Solids, total dissolved 260 682
Solids, suspended 78 12
Hardness 300 600
Iron, total ' - , 0.01 0.01
Iron, dissolved 0.01 0.01
Manganese, total 0.91 0.11
Aluminum, total 0.10 0.10
Zinc, total 0.06 0.33
.Nickel, total 0.01 0.01
Strontium, total 0.30 0.40
Sulfates 68 325
Chloride 6.0 8.7
Fluoride 0.25 0.25
Ammonia 0.75 0.30
All average qualities based on one grab sample.
All results expressed in mg/1 except for, pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and sediment-bearing samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
161
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Mine Code a-5
Mine O5 is a surface mine located in northeastern Wyoming
operating in the Wyodak (sub-bituminous) coal seam. The
total mine encompasses approximately 729 hectares (1,800
acres). Coal is mined at the rate of 2,449 KKG (2,700 tons)
per shift. Based on the 1973 production of 658,482 KKG
(726,000 tons), the estimated life of the present reserves
is 50 years.
The analytical quality of the waste water is shown in Table
25. This water is channeled and pumped where necessary,
into a large collection basin where the suspended solids are
settled before the mine water is discharged. A diagram of
the treatment sequence is shown in Figure 38.
162
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FIGURE 38
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE U-5
MINE SEEPAGE
SETTLING
POND
EFFLUENT TO CREEK
-------
Table 25
Analytical Data - Mine u-5
Constituent
Raw Mine Drainage Sediment-Bearing Effluent
Point 05-1 Point 05-2
Average Quality* Average Quality*
pH 8.0
Alkalinity 440
Specific Conductance 2470
Solids, total dissolved 2238
Solids, suspended 104
Hardness 1140
iron, total 0.47
Iron, dissolved 0.03
Manganese, total 0.10
Aluminum, total 0.50
Zinc, total 0.25
Nickel, total 0.01
Strontium, total 2.2
Sulfates 1087
Chloride 58
Fluoride 0.56
Ammonia 3.2
7.6
414
2970
2742
18
1280
0.20
0.01
0.15
0.20
0.20
0.06
2.6
992
138
0.48
7.2
*Based on one grab sample.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and sediment bearing samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
164
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Mine Code W-2 • .
Mine W-2 is located in southern West Virginia, and has both
surface and deep mining operations in the Powellton
(bituminous) coal seam. Both mines together encompass about
3,443 hectares (8,500 acres), Based on the 1973 production
of 151,200 KKG (166,700 tons) the estimated life of the
present reserves is greater than 300 years.
Mine discharges are pumped into a large 5,980 cubic meter
(1.58 million gallon) settling pond for removal of suspended.
solids before being discharged to the nearby stream. Sludge
removal from this basin is accomplished with a drag line
with burial of the. sediment in a nearby strip pit.
Suspended solids are effectively removed from the drainage
by this sedimentation pond. Analytical data is presented in
Table 26. A diagram of the treatment sequence is shown in
Figure 39.
165
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FIGURE 39
SCHEMATIC DIAGRAM FOR TREATMENT FACILITIES AT MINE W-2
a*
a*
45.29 liters per second
SETTLING
POND
EFFLUENT TO CREEK
45.29 liters per second
| SLUDGE TO STRIP PIT
^""^^™ —^"^^ -MMMMM^W •MMMMM»
-------
Table 26
Analytical Data - Mine Code W-2
Constituent
Raw Mine Drainage
Point W2-1
Average Quality*
PH
Alkalinity
Specific Conductance
Solids, total dissolved
Solids, suspended
Hardness
Iron, total
Iron, dissolved
Manganese, total
Aluminum, total
Zinc, total
Nickel, total
Strontium, total
Sulfates
chloride
Fluoride
Ammonia
7,7
58
570
566
60
289
0.24
0.24
0.13
0.10
0.13
0.01
1.04
223
3.3
0.18
0.09
Sediment-Bearing Effluent
Point W2-2
Average Quality*
7.7
44
530
510
11
246
0.06
0.06
0.12
0.10
0.16
0.01
0.93
193
3.3
0.15
0.06
*Based on one grab sample.
All results expressed in mg/1 except for pH and specific
conductance.
The reported cations listed above were analyzed for both
total and dissolved concentrations. Significant differences
were not measured except where otherwise reported.
The raw and sediment bearing samples were analyzed for
arsenic, barium, boron, cadmium, chromium, copper, mercury,
molybdenum, lead and selenium, but these were not detected
in significant concentrations.
167
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Mine Code W-9
Mine W9 represents a surface mine located in southwestern
Washington operating in the Smith and Big Dirty (sub-
bituminous) coal seams. The total mine encompasses
approximately 4,253 hectares (10,500 acres). Based on the
1973 production of 2,928.700 kkg (3,229,000 tons), the
estimated life of the present reserves is 35 years.
Waste water from mining operations contains 10,000 - 15,000
mg/1 of suspended solids. This water is directed to a
primary settling basin where the majority of the suspended
matter is removed. The effluent from this basin contains
120 - 130 mg/1 suspended solids in the form of colloidal
clays which tend to naturally remain in suspension for
periods often exceeding one week. This water is treated
with a high molecular weight organic anionic
polyelectxolyte, used as a primary coagulant, then allowed
to settle in a secondary basin. As documented in an article
of Mining Congress Journal entitled "Surface Mine Siltation
Control," the suspended solids can be reduced to less than
25 mg/1 (H - 15 Jackson Turbidity Units) in this final
effluent; however, to achieve this quality of water a rather
high dosage (10 mg/1) of polyelectrolyte is required.
Depending upon quantity of rainfall, the two settling basins
provide a detention of 8 to 23 hours for flows averaging up
to 632 liters per second (10,000 gallons per minute).
168
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Pollutant Reductions Achieved by Present Treatment
Technology
Pollutant removals for each of the classes of mine drainage
have been determined by this study. In some instances,
known waste treatment technology from other industries has
been translated for treatment *of certain parameters in mine
drainage. A discussion of the removal efficiencies for the
various treatment methods follows.
pH, Acidityf and Alkalinity. Acid mine drainage contains
mineral acidity in the form of sulfuric acid which occurs by
the oxidation of pyritic iron compounds associated with the
coal seams. This acidity can be totally neutralized by the
addition of an alkali, namely lime, limestone, caustic soda,
soda ash, or anhydrous ammonia. In almost all cases, lime
in either the hydrated, by-product, or quick lime forms is
used by the coal industry for neutralization purposes
because of its availability, ease of handling, and
reliability of results. For those drainages where acidity
is either the main pollutant encountered, or the flow is
relatively small, soda ash and caustic soda have both been
successfully used, as they are simple to apply and react
quickly. Care must be taken not to overfeed these alkalis
to the degree that caustic conditions are created in the
treated effluent.
A pH determination is a control indicator of the efficiency
of the removal of total acidity in acid mine drainage. To
be an effective indicator of the total acidity of a
discharge effluent from a treatment facility there must be
sufficient time allowed for the reaction between the acid
mine drainage and the alkali to go to completion and the pH
to stabilize. This is particularly true when pH
determination is used as an effluent limitation.
Iron. Iron in both the ferrous and ferric forms occurs in
acid or ferruginous mine drainage at significant levels. It
has been demonstrated that iron can be removed as the
insoluble hydroxide by lime neutralization to levels of less
than 2.0 mg/1. It was observed that these removals are
dependent upon an adequate pH level and require effective
sedimentation units. Lime effects better iron removals than
the other alkalis and lower iron concentrations were
apparent as the pH was increased above 7.0. Temperature may
have an effect upon the removal of iron and other metals.
Detention periods in settling basins or thickners were not
observed to be important as long as the minimum detention
was provided. This varies from plant to plant, but at least
two hours detention is necessary.
169
-------
In most plants, ferrous iron is oxidized by aeration once
the alkali has been added to raise the pH of the drainage to
an alkaline condition. This then changes all of the iron to
the ferric form, which can be removed at lower pH»s than
ferrous iron. Mine A3, however, has found it more
advantageous to remove iron as ferrous hydroxide since a
more dense sludge is obtained. This usually requires
somewhat higher pH in the range of 8.5 to 9.5. Mine AU has
demonstrated that iron oxidation is easy to accomplish and
the use of a long, open trough between the lime mix tank
and the settling basin has eliminated the need for
mechanical aeration equipment.
In a few instances, such as Mine Dl, it was found that the
mine drainage was alkaline but contained iron at
unacceptable levels. It was demonstrated here that aeration
and sedimentation with the aid of a coagulant will remove
the iron to an acceptable discharge level.
Manganese. Manganese occurs in most acid or ferruginous
mine drainages from coal mining operations. This cation can
also be removed in the neutralization process as an
insoluble hydroxide. The pH required for removal of
manganese is somewhat higher than that for ferric iron. It
was demonstrated by Mines A2, B2, D3, DU, E6, F2, and K7
that substantial reductions to about 1.0 mg/1 can be
achieved when the pH is raised to 7.5 or higher.
Essentially complete removal cannot be achieved unless the
pH is raised to above 9.0 and closer to a pH of 10.0, as
shown by Mines A3 and K7. It was also demonstrated by Mine
D5 that sodium alkalis do not remove manganese as well as
lime.
Aluminum. The occurrence of aluminum in acid or ferruginous
mine drainage is more varying than either iron or manganese.
In some mines, aluminum concentrations are very high, and in
others it is not present at all. Aluminum was shown to be
very easy to remove as the insoluble hydroxide. Complete
removals were demonstrated at Mines A2, A3, B2, D3, and D5,
where the pH in the neutralization process was controlled at
levels higher than 7.5. It is important to note that
aluminum is an amphoteric metal, which means that it is
soluble in both acid and alkaline forms. Theory indicates
that aluminum should redissolve if the pH is not controlled
to within a close range; however, this effect was not
observed in the plants studied.
Sulfates. sulfates are the basic anion contained in mine
drainage. Sulfate concentrations increased in direct
proportion to the amount of acidity and iron contained in
170
-------
acid or ferruginous mine drainage. Sulfates are not removed
in the neutralization process unless the concentration is
greater than the solubility product for gypsum (calcium
sulfate) formation. This usually occurs at sulfate
concentrations greater than 2,500 mg/1. When sulfates are
in excess of this, then removals can be expected. The
extent of this will depend upon the amount of calcium ion
available for gypsum formation. Since treatment plants are
operated for pH control, there is often an inadequate
availability of calcium ion from the lime being used for
neutralization to achieve maximum sulfate removals.
Gypsum presents problems in the operation of many treatment
plants. Gypsum forms a very hard crystalline scale which
increases in thickness on anything it contacts. Quite
often, tanks, pipes, and mixing equipment can be rendered
totally useless because of gypsum formation. In addition, a
delayed formation of gypsum crystals in the effluent of the
treatment plant can significantly increase the suspended
solids analysis for that discharge. This was a noted
problem in some samples collected during this project.
Where gypsum precipitation is a problem, water samples
should be analyzed within one hour to accurately determine
suspended solids concentrations.
Suspended Solids. The presence of suspended matter in acid
or ferruginous mine drainage is not significantly important
since the commonly applied neutralization process involves
chemical reactions in which insoluble precipitates are
formed. Following this, sedimentation in either earthen
basins, large impoundments, or mechanical clarifiers is
employed to effect very good removals of high suspended
solids as demonstrated by Mines A3, A4, B2, D5, 16, F2, K6,
and K7. Suspended solids removals to less than 30 mg/1 have
been demonstrated. The affect of gypsum formation as'
disucssed under sulfates was noticed at Mines Al, A2, and
Suspended solids removals were also observed in settling
ponds for alkaline mine drainage such as at Mines D6, N6,
and U5.
Pressure or gravity filtration can also be used for the
removal of suspended solids. While these units are not
being used by the coal industry, the application has been
demonstrated elsewhere; namely, iron and steel, metal
finishing, and for effluent polishing of biological systems.
Considering the volumes encountered, high-rate, mixed-media
pressure filters seem most applicable for removing suspended
matter from either the effluent of a conventional lime
171
-------
neutralization system after gravity settling, or a sediment-
bearing discharge. Removals of 25 to 200 mg/1 may be
necessary in flows ranging from 15.78 liters per second (250
gallons per minute) to more than 63.1 liters per second
(1,000 gallons per minute).
Considering the effluent quality required, and the flows and
loadings to be encountered, high rate, mixed-media^ pressure
filters are the most applicable to this waste water
treatment problem. Commonly known as deep bed or in-depth
filtration, the process differs from the usual filtration
techniques in that solids are removed within the filter
media and not on its surface. Higher filtration rates are
desirable since the particles are to be forced into the bed.
The effluent suspended solids concentration from deep bed
filters will be on the order of 10 to 20 mg/1 depending upon
the filter media size and particle diameter of solids
encountered.
Other Parameters. Mine drainage was also observed to
contain other parameters in varying concentrations such as
zinc, nickel, fluoride, calcium, magnesium, and ammonia.
Calcium and magnesium are the metals normally associated
with hardness in water and are not presently considered to
be pollutants. Zinc and nickel were found to occur up to
one or two milligrams per liter. These metals were
essentially completely removed in the neutralization process
as insoluble hydroxides with proper pH control.
Fluoride was found to be present in mine drainage as a
direct affect of coal mining. The concentrations observed
were usually slightly in excess of the recommended limits
for public drinking water supplies. While fluorides can be
removed as insoluble calcium fluoride in a neutralization
process, their level of occurrence was usually below the
solubility for this compound, and removals were not
observed.
Ammonia was also found to be present in acid mine drainage.
This compound was usually reduced several milligrams per
liter by the neutralization process.
172
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SECTION VIII
COST, ENERGY, AND NON-WATER QUALITY ASPECTS
MINE DRAINAGE TREATMENT
Costs
Construction costs for plants treating mine drainage were
obtained from many of the coal companies interviewed during
this study. Most of these treatment facilities were
constructed during the last six years. The construction
costs obtained are generally low when compared to the costs
for similar waste treatment facilities in other industries.
These low costs may be reflected in the use of small, rural
contracting firms for excavation and construction of the
facilities and in the fact that much of the work may have
been performed by the coal companies themselves. These
costs were difficult to obtain for the most part as they
were not maintained as a separate cost account by most of
the firms.
Plants for treating acid mine drainage must all provide the
same essential equipment including lime storage, feeders,
mixers, control facilities, and housing, independent of the
flow encountered. The associated facilities such as raw
water pumps, holding ponds, aerators, aeration basins and
settling ponds or clarifiers may have a cost that varies in
proportion to the plant's design flow. For settling ponds
treating alkaline mine drainage this is not always true, as
the detention provided for sedimentation will vary depending
upon the sludge storage capacity provided. Some plants
provide settling ponds with detentions of from one to three
days while others use large impoundments that provide sludge
storage for several years.
Basis Of Cost Estimates
The more reliable construction costs obtained were adjusted
to September, 1974 costs using the Engineering News Record
(ENR) Construction Cost Index. For determination of annual
capital costs, a straight-line depreciation over fifteen
years was used with an 8 percent annual interest rate.
A complete cost breakdown for several AMD plants including
adjusted (197t) initial investment, capital depreciation,
operating and maintenance, and energy, power and chemicals
173
-------
costs are presented as Water Effluent Treatment Costs,
Tables 27, 28 and 29.
Where initial construction costs for plants treating acid
mine drainage were incomplete, estimates were used for:
1, Land at $2,469 per hectare ($1,000 per acre).
2. Excavation and pond construction at $0.31 per cubic
meter ($1.00 per cubic yard) of total volume.
3. Fencing at $16,«0 per lineal meter ($5.00 per
lineal foot) .
«. Sludge volume at ten percent of plant flow and two
percent solids by weight.
Disposal at $0.026 per thousand liters ($0.10 per
thousand gallons), or $4.25 per cubic meter ($3,25
per cubic yard) of sludge dried to sixty percent
solids.
5. Power usage at $0.025 per kilowatt hour.
6. Operating manpower at $9.00 per hour which includes
overhead and fringes.
The adjusted investment costs were also used in developing
Figure UO where construction cost per unit capacity is
plotted against the design capacity. A breakdown of typical
construction costs for three AMD plants, two of which were
not included in the survey, is presented in Table 30.
Operating costs were also obtained from many of the AMD
plants visited. When available, the cost were obtained for
chemical usage, electricity, sludge disposal and manpower.
These are also presented in Tables 27, 28 and 29.
Alkaline mine drainage frequently use settling basins for
suspended solids removal. A review of those basins
constructed indicates that there is no correlation between
basin capacity and the discharge flow rate; i.e., while a
minimum detention is necessary, the actual size of existing
basins depends more on the physical characteristics of the
area used and the needed volume for sludge storage. As a
minimum, at least one day's detention should be provided.
Based on this, earthen pond construction can be estimated at
$1,05 per cubic meter of capacity ($5.00 per thousand
gallons).
174
-------
The design of a filtration system for either acid mine
drainage or alkaline mine drainage will vary depending upon
the conditions encountered. A simple system would consist
of two settling basins in series preceding the filters. The
secondary pond would serve as the source for both filter
feed (raw water) and backwash water. Following filter
cleaning, the backwash water would be discharged into the
primary settling pond. In such a system, the filtration
system would consist of feed pumps, filters, backwash pumps,
control building and associated piping.
While high-rate filters are very reliable, a minimum of two
units must be provided. Some manufacturers claim filtration
rates up to 13.58 liters per second per square meter (20
gallons per minute per square foot, the commonly used design
rate is 6.79 liters per second per square meter (10 gallons
per minute per square foot) and is used here for estimating
purposes. As an example, a mine drainage of 63.1 liters per
second (1,000 gallons per minute) would require two, 2,11
meter (eight ft) diameter filters. The cost for deep bed
filtration systems in these low design flow ranges can be
estimated at $6.31 to $7.89 per liter per second ($100 to
$125 per gallon per minute) of design capacity. Operating
costs for such systems are low and are estimated to be $5.30
per million liters ($20.00 per million gallons) filtered,
which includes the cost for power. Labor requirements are
minimal with only daily checks of the control system
required.
Energy Requirements . •
As shown on Tables 27, 28 and 29, energy requirements for
the operation of mine drainage treatment facilities can be a
siginificant part of the overall operating cost. This is
attributed mainly to the cost of operating mine dewatering
pumps, which possibly should be considered as a direct
mining cost and not as a mine drainage treatment cost. For
the most part, these costs constitute more than half of the
power demand. Therefore, for future treatment plants to be
constructed as a result of this effluent guidelines program,
the additional power demand at each mine will be small.
Mine dewatering pumps are in operation and additional power
requirements will be for several motors in the treatment
system.
175
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Table 27
WATER EFFLUENT TREATMENT COSTS
COAL MINING INDUSTRY
ACID MINE DRAINAGE TREATMENT PLANTS
Treatment Technology For
Levels I, II, and III as
Exhibited by Plants Identified Treatment Plants for Mines
D4 E6 F2
Investment (Adjusted For
1974 Dollars) $172,OQfi _$453,100 $340,100
Annual Costs:
Capital Costs 8,627 22,729 17,060
Depreciation 11,467 30,206 22,673
Operating & Maintenance 6,570 26,280 9,360
Chemicals 18,000 65,700 62,415
Energy and Power 15,030 12,024 25,716
Total Annual Cost $59,694 $156,939 $137,226
Effluent Quality:
Effluent Constituents
Parameters (Units)* Resulting Effluent Levels
Design flow, cu m/day 5450 4543 3271
Iron, total, mg/1 -2.0 -1.5 -1.0
pH (all 6-9) 6.8 8.2 8.9
Manganese, mg/1 -1.0 -1.0 -0.5
Suspended Solids, mg/1 -200 - 25 - 25
*For raw waste loads, refer to case histories in Section VII.
- Less than
176
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TABLE 28
WATER EFFLUENT TREATMENT COSTS
COAL MINING INDUSTRY
ACID MINE DRAINAGE TREATMENT PLANTS
Treatment Technology For
Levels I, II, and III as
Exhibited by Plants Identified
Investment (Adjusted For
1974 Dollars)
Annual Costs:
Capital Costs
Depr eci at ion
Operating S Maintenance
Chemicals
Energy and Power
Treatment Plants for Mines
K6
$477,200
23,937
31,813
14,600
180,200
9,352
K7
$540,400
27,107
36,027
8,672
164,250
9,1«3
Total Annual Cost
$259,902 $245,199
Effluent Quality:
Effluent Constituents
Parameters (Units)*
Flow, cubic meters/day
pH (All 6-9)
Iron, total, mg/1
Manganese, mg/1
Suspended Solids, mg/1
Resulting Effluent Levels
25,936
8.0
-2.0
-0.5
- 25
28,719
8.8
-2.0
-0.5
- 25
* For raw waste loads, refer to case histories in Section VII,
- Less than
177
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Table 29
TYPICAL CONSTRUCTION COSTS
ACID MINE DRAINAGE TREATMENT PLANTS
FLOW (Cubic Meters Per Day)' 5,450
COSTS
Land
Holding Basin
Control Building
Lime Storage
Lime Feed and Mixer
Aeration Facilities
Settling Basins
Fencing and Roads
Sludge Disposal Equipment
Instruments and
Electrical
Pumps
Other
Total Construction Cost
(1974)
Plant
X Y
5,450
6,540
10,000
—
25,000
17,500
5,000
—
85,000
6,500
— —
12,000
35,000
7.500
10,000
. —
25,000
22,000
16,000
20,000
55,000
8,000
48,000
18,000
35,000
16,000
50,000
12,500
37,000
18,000
6,sao
23,500V
26,500
10,000
68,000*
42,000
33,500
20,000
$203,500 $273,000 $348,000
*Includes $40,000 for a sludge disposal basin with a twenty
year life.
178
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Land Requirements
Since many treatment plants employ earthen settling basins
for the treatment of mine drainage, land requirements can
become very significant. At some plants, such as Mines A2,
A4r D4, and D3, very large settling basins and sludge
storage areas were formed by damming entire valleys. In
most cases, however, treatment plant facilities are confined
to land requirements of less than 10 acres.
Most mine drainage treatment facilities are constructed in
rural areas. The cost of land for these facilities should
not be a significant aspect of the total cost of the plant.
However, several companies reported that they were faced
with paying extremely high costs for rural land when the
local owners learned of the coal companies needs. This can
always be expected in the case of supply and demand.
179
-------
u
H
§
u
CONSTRUCTION COST VS. CAPACITY
ACID MINE DRAINAGE TREATMENT PLANTS
(Costs in 1974 Dollars)
10
10"
103
10:
$10
$100
COST/UNIT CAPACITY
DOLLARS PER CUBIC METERS A DAY
Figure 40
$1,000
180
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Table 30
WATEE EFFLUENT THEATMENT COSTS
COAL MINING INDUSTRY
ACID MINE DRAINAGE TREATMENT PLANTS
Treatment Technology For
Levels Ig II, and III as
Exhibited by Plants Identified
Treatment Plants for Mines
Al A4 D3
$340,800 $193,500 $276,000
Investment (Adjusted For
1971 Dollars)
Annual Costs:
Capital Costs
Depreciation
Operating & Maintenance
Chemicals
Energy and Power
Total Annual Cost $ 81,558 $ 61,376 $ 91,510
17,095
22,720
9,855
7,200
24,688
9,706
12,900
19,710
10,950
8,110
13,844
18,400
9,855
31,200
18,241
Effluent Quality;
Effluent Constituents
Parameters (Units)*
Design flow, cu m/day
pH (All 6-9)
Iron, total, mg/1
Manganese, mg/1
Suspended Solids, mg/1
Resulting Effluent Levels
3816
7,2
-2.0
1.1
-100
5420
8.0
-1.0
-2.5
- 25
2726
7.8
-2.0
-1.0
- 75
* For raw waste loads, refer to case histories in Section VII,
- Less than
181
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Sludge Disposal
For those waste materials considered to be non-hazardous
where land disposal is the choice for disposal, practices
similar to proper sanitary landfill technology may be
followed. The principles set forth in the EPA's Land
Disposal of Solid Wastes Guidelines (CFR Title 1Q, Chapter
1; Part 241) may be used as guidance for acceptable land
disposal techniques.
For those waste materials considered to be hazardous,
disposal will require special precautions. In order to
ensure long-term protection of public health and the
environment, special preparation and pretreatment may be
required prior to disposal. If land disposal is to be
practiced, these sites must not allow movement of pollutants
such as fluoride and radium-226 to either ground or surface
water. Sites should be selected that have natural soil and
geological conditions to prevent such contamination or, if
such conditions do not exist, artificial means (e.g.,
liners) must be provided to ensure long-term protection of
the environment from hazardous materials. Where
appropriate, the location of solid hazardous materials
disposal sites should be permanently recorded in the
appropriate office of the legal jurisdiction in which the
site is located.
The disposal of the sludges produced in the treatment of
acid mine drainage is an increasing problem. The earlier
constructed plants, those from 1967 through 1970, normally
provided facilities which consisted of settling ponds having
the capacity for one or two months storage of sludge. The
procedure, then, was to take the facility out of operation,
and then remove the sludge with front-end loaders. It was
found that this was a very messy and difficult operation.
The more recently constructed plants now provide settling
basins which have capacities of many millions of gallons and
can provide for sludge storage for several years. This
appears to be a good solution to the sludge disposal
problem, providing that suitable land is available for the
construction of these large impoundments.
Another method employed for the disposal of sludge produced
from treating AMD is to provide for the continuous or
intermittent removal from the settling facility for disposal
into portions of active mines. This arrangement has also
been acceptable when abandoned mines are accessible.
Chemically, this should not create a water pollution
problem, even if the sludge contacts acid mine drainage, as
long as the iron is in the ferric form.
182
-------
Availability of Chemicals
As was discussed, neutralization chemicals include lime,
limestone, soda ash, and caustic soda. By far, lime is the
most commonly used neutralizing agent. Limestone, the raw
material is readily available for production of lime;
however, there is presently a tight market for the
availability of lime due to the closing of several plants
for air pollution problems. Soda ash briquettes have also
been commonly used by many mines to neutralize intermittent
acidic discharges, it has been reported that there is a
scarcity of soda ash in this form. If so these mines will
have to resort to other alkalis for treatment. On the
whole, it does not appear that the availability of alkalis
will affect the treatment of mine drainage from active
mines.
PREPARATION PLANT WATER RECIRCUIATION
A majority of the coal preparation plants visited in
conjunction with development of this document have closed
Water circuits. These facilities employ thickeners, filters
or settling ponds to effect most of tLhe necessary water
clarification prior to recirculation. For those existing
plants that do not presently have a closed water circuit,
recycling water from settling basins in many cases will be
the most practical and economic method for conversion to a
closed circuit. Exceptions to this assumption would be
those plants using thickeners with an open water circuit.
These washeries can be converted by adding filters to the
system.
The cost of converting to a recycle system is primarily
dependent on the purchase and installation cost of the water
handling equipment necessary to meet the plants consumption
demands. This may vary considerably from one plant to
another, depending on the type and size of equipment
utilized to process the coal. It would be extremely
difficult and inaccurate to project the cost of implementing
a recycle system considerate of every contingency.
Therefore, Table 31 has been prepared to illustrate the
major expenditures required to deliver a variety of flows
under different hydraulic head conditions. It is assumed
that at least one pond is presently being used in any open
circuit system for clarification prior to discharge and that
this pond will be utilized as a holding basin for a recycle
system* An additional holding pond may be necessary to
allow emergency dewatering of the total plant system. The
particular capacity required for holding basins is dependent
on the total volume of water used by the plant during normal
183
-------
TABLE 31
COAL. PREPARATION PLANT WATER CIRCUIT CLOSURE COSTS
00
Fluid
Delivery
Requirements
63
Uter/ae
1OOO
GPM
198
liter/sec
2500
3PM
316
liter/see
5,000
GPM
631
10,000
GPM
947
liter/sec
15,000
GPM
Head condZ
meters &feet
16m
60«
pom
too*
76m
250'
16TT
50'
QOm
100'
76m
260'
15m
BO'
3Om
100'
76m
250'
15m
50'
30m
too1
78m
aso1
15m
50'
aom
too1
78m
250'
VALVE & PUMP REQUIREMENTS
PUMPS
H.P,
25
4O
100-
50
100
250
100
200
450
150
350
800
250
600
125C
Mo.
Req
1
£
1
g
1
2
1
%
1
2
1
2
1
2
1
2
1
2
1
g
1
2
1
2
1
2
1
2
1
2
Unit
Cost
$ 4,300^
4J9QO
7,525
10,000
11.700
20,509
12.500
23,000
30,000
19,000
34.000
57,5OO
28.600
64,800
73^,000
Total
Coat
$ 4.300
8.600
4,600
QfSOO
7t828
1B,O50
10,OOO
2O.OOO
11 ,700
23,400
2O.50O
41 ,OOO
12.500
25^000
23,000
46,000
30,000
60,000
19,000
38.000
34.000
68,000
57,500
116.000
28,600
B7.2OO
64.500
129.OOO
73,000
146.000
VALVES
TVPe
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
• B
A
B
No.
Req
if
i
X^
• '
Unit
Qoat
Gates =
$480
Checks**
$500
Gates B
$900
Checks=
$1000
$2300
Checks=
$2400
Gates =
$38OO
$4OOO
Gates =
$6725
Checks^
$7OOO
Total
Cost
$ 1,400
3,250
1,400
3,250
1,400
3,250
2. BOO
3. 500
8,800
6,300
2,800
6,500
7.OOO
J6.30JL.
7,000
ie,3oo
^7,000
16,300
11,600
27,OOO
11,600
27,000
11 r800
J7.0QQ_
20.450
47.625
20,450
47.625
9O,4BO
47 „ 625
valve %
pump
Install
P3OO
31 .OOO
63,300
38,000
77,300
32,600
67,000
47,6OO
97,000
71,100
144,000
51 ,080
106FS25
86,980
178,685
95,480
195,625
PIPING REQUIREMENTS
(Based on Average Run of
305 msters or 1000'}
Type
J
£
I
Size
20cm
8"
30 cm
12"
46 cm
18"
61 cm
24"
76 cm
30"
Installation
permeter,ft,
$28.25 per
meter
$3.61 per
foot
$42.40 per
meter
$12.83 par
foot
$88.56 per
meter
$27.09 per
foot
$121.62 per
$37.05 per
foot
$154.16 per
meter
$47 per
foot
a*
f j
$U60
3.00
7.0O
3. SO
7.00
18.00
7.00
14.00
35.00
14.00
28 .00
71.00
21.00
42 .00
106.0
jse'
fiw
•0°°
CLL
m
f*\
|
l
8
5
/•^
•E
5,
i
8
»
•A - 2 Gate Valves & 1 Check Valve
* B - 5 Gate Valves & 2 Check Valves
-------
operation and the precipitation pattern for the geographical
area.
To illustrate the costs presented in Table 31 as they apply
to a given situation, the following example has been
developed.
EXAMPLE
This example is based on a simple Baum Jig cleaning system,
operating three 8 hour shifts each days, 5 day a week.
Plant facilities are located 305 meters (1000 ft) away from
and 31 meters (100 ft) above a settling pond presently used
to retain and treat plant water until it can be discharged.
It is anticipated that this pond alone will sufficiently
serve a recycle circuit.
A sump already in the plant precludes the necessity of an
emergency holding pond system. Presently, the plant is
producing 566 kkg (625 tons) of clean coal each hour and
utilizing process water at the rate of 158 I/sec (2500 gpm).
Assuming the present discharge will be converted to recycle
using a back-up pump in addition to the primary pumpr the
following installation and operating costs can be extracted
from Table 31.
INSTALLATION
Two 100 hp. Pumps 9 $11,700 each = $ 23,400
Five Gate Valves 3 $900 each = a,500
Two Check Valves a $1000 each = 2,000
Build Platform 6 Mount Pumps
B Valves in existing Pond = 1,000
Install 305 meters of 30 cm pipe
at $U2.UO per meter (1000* of 12"
steel pipe
» $12.93 per foot) 129,300
Total Installation - $160,200
OPERATION
1 pump cont. operation for
3-8 hr. shifts - 5 days a week
3 $7.00 per shift = $105,00 Mo.
185
-------
-------
SECTION IX
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
GUIDELINES AND LIMITATIONS
INTRODUCTION
The effluent limitations which must be achieved by July 1,
1977 are to specify the degree of effluent reduction
attainable through the application of the Best Practicable
Control Technology Currently Available. This is generally
based upon the average of the best existing plants of
various sizes, ages, and unit processes within the
industrial category and/or sub-category. Consideration must
also be given to:
a. the total cost of application of technology in
relation to the effluent reduction benefits to be
achieved from such application;
b. the size and age of equipment and facilities
involved;
c. the processes employed;
d. the engineering aspects of the application of
various types of control techniques;
e. process changes;
f. non-water quality environmental impact (including
energy requirements)
Also, Best Practicable control Technology Currently
Available emphasizes treatment facilities at the end of a
manufacturing process, but includes the control technologies
within the process itself, when the latter are considered to
be normal practice within an industry.
A further consideration is the degree of economic and
engineering reliability which must be established for the
technology to be "currently available." As a result of
demonstration projects, pilot plants, and general use, there
must exist a high degree of confidence in the engineering
and economic practicability of the technology at the time of
commencement of construction or installation of the control
facilities.
187
-------
Acid or Ferruginous Mine Drainage.
The effluent limitations suggested in the draft report were
derived after careful analysis and review of effluent water
quality data collected from exemplary plants. This data was
substantiated by historical effluent quality information
supplied by the coal industry and regulatory agencies.
Despite a broad data base in terms of number of facilities
visited, major problems were encountered in establishing
guidelines based only on the initial samples collected. Due
to time restrictions, the initial sampling program was
conducted during the summer months. During this period pit
pumpage and runoff from surface mines is minimal, and
samples of these types of drainage could not always be
obtained. In addition, the operation of acid mine drainage
treatment facilities was alleged to be much better than
during winter and spring. Effluent limitations based solely
upon the data obtained during the summer months would have
been extremely low and possibly could not be achieved by the
exemplary facilities during the winter and spring seasons.
To compensate for this shortcoming, the initial analytical
data and available historical analyses were compared
statistically to develop the suggested effluent limitations.
Historical effluent sample analyses representative of either
daily samples or weekly averages of daily samples, were
available for 12 of the exemplary treatment plants. This
historical data substantiated the information obtained
during the initial sampling program, and indicated that the
concentrations of pollutants in treated mine drainage varies
and was possibly affected by weather conditions. The
initial sample data and the historical information also
indicated that iron removal was improved by adjusting the pH
upward from six. Variations in pH and total iron
concentrations are graphically illustrated for three of
those facilities in Figures 41 through i»9. Total iron was
selected for several reasons: 1) iron is one of the most
commonly analyzed constitutents of mine drainage, thus data
is much more complete for this parameter; 2) iron reduction
is generally representative of the overall effectiveness of
the neutralization process.
These plots show, as did the initial sampling program, that
there are only minimal fluctuations in effluent quality
during the summer months. However, daily fluctuations are
more sporadic and mean concentrations are greater during
fall, winter, and spring months. It should be noted that
these fluctuations of pollutant concentrations may not be
indicative of effectiveness of the treatment process, but
could be reflecting inefficiencies in the operation of
188
-------
00
AO
JAN. FEB. MAR. APR. MAY JUNE JULY AUGl SEPT. OCT. NOV.
HISTORICAL DATA MONTHLY TOTAL IRON - TREATMENT PLANT A-l
Figure 41
DEC.
-------
vQ
O
9-
i
JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV.
HISTORICAL DATA-MONTHLY pH-TREATMENT PLANT A-l .
Figure 42
DEC.
-------
vo
SJ -
JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC.
HISTORICAL DATA MONTHLY TOTAL IRON-TREATMENT PLANT A-1
Figure 43
f
t
ft or
-------
vo
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i f
ij:
3 c
n
5'
1=
JAN.
FEB. MAR. APR, MAY JUNE JULV AUG. SEPI OCI NOV.
HISTORICAL DATA-MONTHLY pH-TREATMENT PLANT A-|
Figure 44
DEC.
-------
VD
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33
srs.
1
p
!
i
S
S'
I
a
i
I
i
a*.
S-
JAN, FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC,
HISTORICAL DATA MONTHLY TOTAL IRON - TREATMENT PLANT A-3
Figure 45
-------
£ ~3 3 =
VO f i o
*• I ' 1
, ^ g E,
s <£
o -f
•a in
If
^J
f f
n
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3-
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*r
JAN.
FEB.
MAR.
APR. MAY JUNE
JULY
AUG. SEPT. OCT. NOV. DEC,
HISTORICAL DATA-MONTHLY pH TREATMENT PLANT A-3
Figure 46
-------
VO
£
I
JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT NOV. DEC.
HISTORICAL DATA MONTHLY TOTAL IRON-TREATMENT PLANT A-3
Figure 47
-------
er>
§
o
1-
i. a
I
y
i
JAN.
FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV.
HISTORICAL DATA-MONTHLY pH-TREATMENT PLANT A-3
Figure 48
DEC.
-------
JAN. FEB. MAR, APR, MAY JUNE JULY AUG. SEPT, OCT NOV.
HISTORICAL DATA DAILY TOTAL IRON - TREATMENT PLANT K-7
Figure 49
DEC.
II'
* ar
-------
individual plants, or maintenance problems at individual
plants. Treatment plants in the same proximity do not show
significant fluctuations during the same time periods.
It was found that mean iron concentrations during these
periods of fluctuations at individual treatment plants were
slightly less than 3.5 mg/1 with maximum concentrations
approaching 9.0 mg/1. Statistical evaluation of this
historical data and comparison with imitial sample data
revealed that the reduction of pollutants during fall,
winter and spring was approximately 1.29 standard deviations
above that attainable during the summer. On this basis, the
suggested 30 day average effluent limitations were computed
for each critical parameter by adding 1.29 standard
deviations to the mean value computed from the initial
sample data. This indicated that 80 percent of the
exemplary treatment plants evaluated in the initial study
should be able to meet the limitations at all times.
This rationale was not, however, utilized to establish the
30 day average limitation proposed for total suspended
solids, because there is a technology available which, when
applied in conjunction with normal settling, can achieve the
suggested suspended solids concentrations, coagulants have
been successfully and economically utilized to remove fine
sediment from mine waste water to consistently achieve
suspended solids concentrations observed during the initial
sampling.
Examination of historical data also revealed that maximum
iron values centered around 7 mg/lf or twice the monthly
average value. To maintain uniformity in the establishment
of daily maximums, the maximum daily guideline limitations
were consistently suggested at twice the thirty-day average
values.
To validate and confirm the conclusions and suggested
effluent limitations established in part from historical
data, a further sampling program was conducted during the
winter and spring of 1975.
The suggested guidelines were initially based on careful
analysis and review of effluent water quality data collected
from exemplary plants. The data was substantiated by
historical effluent quality information supplied by the coal
industry and regulatory agencies. Selection of minesites
for the winter and spring sampling program was made,
whereever possible, from those identified as exemplary
treatment facilities during the initial study period.
Plants were considered on the basis of:
198
-------
1) Plant design;
2) mode of operation, i.e., manual/automatic, safety
features and alarm systems, housekeeping, etc.;
3) stability of plant operation (operational problems)
U) range of operating parameters (pH range, flow rate,
settling time) ;
5) historical data indicating potential problems in
meeting the recommended effluent limits.
Based on this analysis, seven plants were selected for
further evaluation. These plants adequately represent the
complete range of operating parameters and are well
designed, maintained, and operated acid mine drainage
treatment plants. Of the seven acid mine drainage treatment
plants selected for this phase of study, six were included
in the orginal list of "best plants;" the remaining plant
was included because modifications and design improvements
completed after the initial sampling program resulted in
improved performance consistent with that of the exemplary
plants* All seven plants are located within southwestern
Pennsylvania and treat drainage from large underground
mines. While this may appear biased toward this specific
locale, it must be pointed out that Pennsylvania has long
been the leader in acid mine drainage treatment technology
and all are in such proximity as to be jointly affected by
weather conditions. In addition, the larger mines of
southwestern Pennsylvania employ the most sophisticated
technology in practice today and are most conscientious in
their maintenance and operational programs.
The sampling technique utilized at the acid mine drainage
neutralization plants winter-spring sampling program
employed automatic samplers to collect composite samples.
The composite samplers collected aliquots at 15 minute
intervals of the influent and effluent for each treatment
plant evaluated during this supplementary study. Once each
day composited samples were manually collected, prepared for
laboratory analysis (by adding the proper preservatives),
and returned to the laboratory. Duplicate samples were
collected at each site and submitted to Bituminous Coal
Research in Monroeville, Pennsylvania for evaluation and
verification of analyses by the National Coal Association.
All samples were analyzed for those parameters that were
most prevalent in the original study. These parameters are
as follows:
PH
Alkalinity
Total Suspended Solids
Iron, Total
199
-------
Iron, Dissolved
Manganese, Total
Aluminum, Total
Nickel, .Total
Zinc, Total
Sulfate, Total
In order to fully assess the treatment plants ability to
comply with the effluent limitations for 30 day averages, as
well as one day maximums, sampling was conducted at each
site for 90 consecutive days. This relatively long duration
of sampling enabled an assessment of the influences of
temperature and precipitation on treatment plant efficiency
during the winter and spring seasons. Sampling was
initiated at the seven mine drainage neutralization plants
on February 4, 1975 and completed May 5, 1975, a period of
91 days.
All data was correlated to daily U.S. Weather Bureau data
and thoroughly reviewed to determine the influence of
weather conditions on the operation of the treatment
facilities. Unusual variations in effluent quality was also
compared to the survey crews' field reports in order that
some account could be made for these occurrences due to
either maintenance or operational problems. In general, it
was not observed that climatological conditions influenced
the treatment of acid mine drainage. Most effluent
variations observed were directly traced to maintenance or
operational problems.
At one plant, however, which utilized a vary large settling
basin, definite effluent variations were observed that were
influenced by weather and other physical factors.
Specifically, suspended solids concentrations in the
effluent from this facility varied significantly during
periods of ice formation or wind conditions. It is felt
that better effluent quality with regard to suspended solids
could be obtained by more proper selection of the point of
discharge from this settling basin. Variations in the
suspended solids concentrations in the discharge from this
large basin were also influenced by a naturally occurring
phenomenon, in which the pond "turned over" at about the
57th day of sampling. This resulted in a definite color
change in the pond as well as a decrease in effluent
quality.
Several days after periods of heavy precipitation, it was
observed that the volume of drainage treated by plants
increased significantly. This also had some affect on
deterioration of effluent quality at those facilities which
200
-------
employed
periods.
clarifiers or settling basins with short detention
In almost all other instances where a significant increase
in concentration of a chemical parameter was measured, the
cause could be accounted for by some operation or
maintenance problem. This included malfunctioning of pH
measuring equipment which subsequently influenced lime
feeding units, build-up of sludge in the settling basin to
the point that there was a carryover in the effluent or
malfunction of some other related plant equipment.
All analytical data on effluent quality was evaluated
statistically for the seven plants studied during the
winter-spring sampling period and the mean and standard
deviation values were calculated. This data is presented
below, with the values initially obtained on effluent
quality during evaluation of the 22 exemplary acid mine
drainage treatment plants examined during development of the
draft document.
Table 32
Winter-spring (1975) Analytical Data
Sanvgle
Parameter Count
Total Iron 567
Dissolved Iron 517
Manganese 517
Aluminum 517
Zinc 517
Nickel 515
Total Suspended
Solids 555
mg/1
0.03
0.01
0.03
0.01
0
0.01
Maximum
mq/1
31.0
2.1
6.0
1.40
0.18
0.29
973
Standard
Deviation
1.51
0.08
0.90
O.ftl
0.02
0.05
1.81
0.18
1.14
0.51
0.02
0.05
3 a
70.27
201
-------
Table 33
22 Best Plants (1974) Analytical Data
Mine Minimum Maximum
Parameter Count mcr/1 mq/1
Total Iron 22 0.15 7.40
Dissolved Iron 22 0.01 0.49
Manganese 22 0.01 3,05
Aluminum 22 0.01 3.83
Zinc 22 0.01 0.59
Nickel 22 0.01 0.57
Total Suspended
Solids 22 1 192
Standard
Deviation
1.9
0.11
0.91
0.74
0.09
0.06
1.48
0.13
0.85
0,85
0.16
0.12
34
44.92
Based upon the close comparison of the mean and standard
deviations values for each of the parameters between the
twenty^two exemplary plants obtained during the summer and
the supplemental sampling survey, the 30 day average and
single day maximum values are proposed as initially
suggested in the draft development document. Further, the
minimum and maximum values for pH are also proposed as
previously suggested.
It does appear that any claim that the these effluent
limitations cannot be achieved through the winter and spring
is not warrented.
In reviewing the data obtained during this supplemental
sampling project, further observations were made toward the
treatment technology in practice and its efficiency in
removing certain pollutants. Specific comments follow:
Acidity, pH - The control of pH in the treatment plant
is most important and should be monitored on a continuous
basis. It was observed that those plants operating to
produce a discharge effluent near the lower pH limit of 6.0
produced effluents of a poorer quality than those that
operated at 7.0 and above. A pB determination is a control
indicator of the efficiency of the removal of total acidity.
To be an effective indicator of the total acidity of a
discharge effluent from an acid mine drainage treatment
facility time must be allowed for the reaction between the
acid mine drainage and the alkali used in treatment, and
this reaction must be allowed to go to completion and the pH
to stabilize. This is particularly true when pH
determination is used as an effluent limitation.
202
-------
gotal Iron - It. was demonstrated that total iron can
be effectively removed by the treatment technology employed
to within the effluent limitations proposed. For the six
plants where complete data is available, violations of the
recommended daily maximum did not cause the 30 day average
values to exceed the proposed limit. "Operational or
maintenance problems were usually the reason for any total
iron values which were in violation of the daily maximum
value,
pissglyeJL Iron - it ' was observed that there was
little problem with these plants in removing dissolved iron.
All plants achieved effluent concentrations of dissolved
iron consistently within the 30 day average value proposed,
although there were some values which exceeded the proposed
daily maximum concentration. After careful analysis of the
data, it was concluded that any facility exhibiting
satisfactory removal of total iron could likewise effect
satisfactory removal of dissolved iron.
Manganese - It was generally observed that removals
of manganese are affected by the operating pH of the
treatment plant. Only one of the plants exhibited
difficulty in removing manganese to a level within the
recommended 30 day average value. It is theorized that this
occurred because the particular plant adds a very small
amount of alkali (and alkalinity} to the raw mine drainage,
thereby not affecting the manganese at all, or else the long
detention period (50 days} permits hydrolysis of
precipitated manganese hydroxide. In any event, manganese
removals to the proposed levels can be achieved through pH
control.
aiundnumJL_Mic_kel and Zinc - Effective removals of
these metals were observed at all plants. There were no
observed values which exceeded the proposed daily maximum
concentrations for nickel and zinc at any of the plants, and
at only one plant did aluminum values exceed the daily
maximum limit. Consequently, it is concluded that well
operated treatment plants have very little problem in
removal of these parameters.
Suspended Solids - The removal of suspended solids by
different methods of gravity sedimentation in these
treatment plants produced widely varying results. First,
only one plant had suspended solids concentrations which
exceeded the recommended daily maximum. This could be
attributed to either an insufficient detention period in,the
settling basin, or to gypsum solids being formed in the
sample. In addition, this same plant (A-2} together with
203
-------
plant A-1 exhibited difficulty in complying with the
recommended 30 day average concentrations. Problems in
plant A-4 can be traced to an observed condition where this
very large impoundment "turned over" due to thermal
stratification. This caused previously settled solids to
raise to the surface and carry-over in the discharge.
Alkaline Mine Drainage
As stated in Waste Characterization (Section V) discharge
effluent and sediment-bearing effluent from alkaline mine
drainage is commonly superior to the quality of treated mine
drainage from the most effluent treatment plants. Alkaline
mine drainage is characterized as not requiring treatment or
only requiring treatment for suspended solids removal.
While conventional neutralization sucessfully controls most
pollutant parameters associated with acid or ferruginous
mine drainage, treated mine drainage freqeuntly contains
suspended solids in excess of the suspended solids
concentration in sediment-bearing effluent from settling
facilities used for alkaline mine drainage. Conventional
neutralization generally requires the addition of solids as
a neutralizing agent which cause an increase in pH of the
mine drainage initiating precipitation of previously
dissolved constituents. This creates additional solids to
be settle out of the waste water.
The primary pollutant in alkaline mine drainage is susended
solids. As established in this section, acid or ferruginous
mine drainage treatment technology is available which, when
applied in conjunction with normal settling, can achieve the
suspended solids concentrations suggested in the draft
document.
As part of the winter-spring sampling program eight surface
mines in selected locations were sampled to verify
fluctuations in effluent quality due to winter-spring
weather variations.
The rationale for selection of settling basins (alkaline
mine drainage) for evaluation differed from that used for
selection of acid mine drainage treatment plants for several
reasons:
1. Alkaline mine drainage is encountered over an extremely
broad geographical area with widely divergent physical and
climatological conditions (unlike the relatively isolated
acid mine drainage of Northern Appalachia).
204
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2. With the exception of total suspended solids, all
parameters are generally within acceptable limits of the
proposed guidelines.
Because the areal extent of alkaline mine drainage is so
wide, sites were selected in locations which, cumulatively,
were considered to be representative of the many variations
found throughout the United States. Based on this criteria
minesites were selected as follows:
2 Surface Mines in Western Kentucky
2 Surface Mines in Wyoming
2 Surface Mines in West Virginia
2 Surface Mines in Eastern Kentucky
The sampling technique used at the surface minesites
employed the use of grab samples. This was necessitated by
the unavilability of power sources at the remote locations
of the sediment basins serving these minesites. Another
factor considered in the decision to utilize grab sampling
was the fact that, aside from the influences of storms,
alkaline drainage from surface minesites is not as
susceptible to plant malfunctions as are neutralization
facilities. Based on this decision, samples were collected
manually at the discharge from each of the minesites'
settling basins. Wherever possible, samples were also
collected of the influent to the sediment ponds; in several
cases this was not possible because drainage entered the
pond from many individual points and a single sample would
not accurately represent the overall quality of the raw mine
drainage.
In addition to the daily grab samples collected at each of
the surface mine sites, weekly composite samples were
collected at each sample location. This too, was
accomplished manually by taking aliquots at each site over a
seven day peribd throughout the study.
Daily grab samples were analyzed for pH and total suspended
solids, while weekly composite samples were analyzed for all
parameters defined above in the discussion of neutralization
plants included in the winter-spring sampling program. As
with the acid mine drainage treatment plants, the duration
of sampling was 90 consecutive days. However, due to he
divergent locations of the minesites involved, considerable
time was required to implement the Sampling program;
consequently, sampling (was not initiated at all sites
simultaneously. ;
205
-------
Computerization of the supplementary samples from
sedimentation ponds where daily samples consisted of only pH
and total suspended solids were analyzed using a soft-ware
program, whereby the sample statistics were obtained without
extensive mine coding.
Sample statistics on these total suspended solids data
included:
1. Individual mine
2. Mine type (surface and underground) for
alkaline mine drainage
3. All sediment bearing effluent
Q. All treated mine drainage
Each analysis included the maximum, minimum, mean and
standard deviation for these total suspended solids data.
Based upon the initial sampling program and the winter-
spring sampling program the 30 day average and single day
maximum values are proposed as suggested in the draft
document.
Coal Preparation Plants and coal Preparation Plant ancillary
Area
For coal preparation plants, it was demonstrated toy a wide
segment of the industry that total reuse of process water is
feasible. Therefore closed systems, or "zero discharge,"
has been proposed for BPT. Drainage from a preparation
plant's immediate yards, coal storage areas, or refuse
disposal areas must comply with the effluent limitations
recommended for Bituminous, Lignite, and Anthracite Mining.
The effluent limitation guidelines and standards for "Best
Practicable Control Technology Currently Available" are
presented in Table 34.
Waste treatment technology for the coal mining industry does
not require highly sophisticated methods. Effective removal
of pollutants contained in mine waste water has been
demonstrated by the industry. For acid or ferruginous mine
drainage lime neutralization has been adequately
demonstrated as being capable of meeting the effluent
limitations requirements for BPT as listed. Effective
removal of iron, manganese, aluminum, zinc and nickel can be
achieved by maintaining proper pH control. For alkaline
mine drainage, sedimentation, or sedimentation with
coagulation, vill meet the limits recommended. In some few
instances it may be desirable to utilize filtration methods
206
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Parameter
TABLE 34
EFFLUENT LEVELS ACHIEVABLE THROUGH.APPLICATION OF THE
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Bituminous, Lignite-, and Anthracite
Mining Services
Bituminous, Lignite* and
Anthracite Mining
Coal Preparation
Plant
Coal Storage,
Refuse Storage
and Coal Prep-
aration Plant
Ancillary Area
Acid or Ferrugi-
nous Mine Drainage
Alkaline Mine
Drainage
30 Day Daily 30 Day * Daily * 30 Day * Daily * 30 Day * Daily *
Average Maximum Average Maximum Average Maximum Average Maximum
fo
O
IRON, TOTAL
DISSOLVED IRON
ALUMINUM..TOTAL
MANGANESE, TOTAL
NICKEL, TOTAL
ZINC, TOTAL
TOTAL SUSPENDED
SOLIDS
s-
-w
It)
S
O
0.
V-
o
OJ
gl
ra
"o
vt
S
0
s-
w
-t->
5
ffl
01
o
d.
«t-
o
O)
5
1
_g
6-9
3.5
0.30
2.0
2.0
0.20
£1.20
35
§-9
7.0
0.60
4;0
4.0-
0.40
0.40
70
6-9
3.5
0.30
2.0
2.0
0.20
0.20
35
6-9
7.0
6-9
3.5
0.60 0.30
4.0 2.0
4.0 2.0
0.40 0.20
6-9
7.0
0.50
4.0
4.0
0.40
0.40 0,20 0.40
70 25 "50
*A11 values except pH tn mg/1,
-------
for effective suspended solids removal from mine drainage.
It was also demonstrated that those alkaline mine drainages
containing dissolved iron can meet recommended limits by
natural aeration in holding ponds.
These guidelines do not appear to present any particular
problems in implementation. The treatment processes
involved are in use by the industry and difficult
engineering problems are not usually involved in design or
construction. The costs estimated in Section VIII are based
primarily on actual plant data, and generally reflect the
entire range of flows encountered, as presented in Figure
40. The costs given represent the average situation.
208
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SECTION X
BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE,
GUIDELINES AND LIMITATIONS
INTRODUCTION
The effluent limitations which must be achieved by July 1,
1983 are to specify the degree of effluent reduction
attainable through the application of the Best Available
Technology Economically Achievable, Best Available
Technology Economically Achievable is determined by the very
best control and treatment technology employed by a specific
point source within the industry category or by technology
which is readily transferable from another industrial
process.
Consideration must also be given to:
a. the age of the equipment and facilities involved;
b. the process employed;
c. the engineering aspects of the application of
various types of control techniques;
d. process changes;
e. cost of achieving the effluent reduction resulting
from the application of this level of technology;
f. non-water quality environmental impact {including
energy requirements).
Also, Best Available Technology Economically Achievable
assesses the availability of in-process controls as well as
additional treatment at the end of a production process.
In-process control options include water re-use, alternative
water uses, water conservation, by-product recovery, good
housekeeping, and monitor and alarm systems.
A further consideration is the availability of plant
processes and control techniques up to arid including "no
discharge" of pollutants. Costs for this level of control
are to be the top-of-the-line of current technology subject
to engineering and economic feasibility. The Best Available
Technology Economically Achievable may be characterized by
some technical risk with respect to performance and with
209
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respect to certainty of costs. The Best Available
Technology Economically Achievable may necessitate some
industrially sponsored development work prior to its
application.
Best Available Technology Economically Achievable is not
based upon an average of the best performance within an
industrial category, but is to be determined by identifying
the very best control and treatment technology employed by a
specific point source within the industrial category or sub-
category, or where it is readily transferable from one
industry process to another, such technology may be
identified as Best Available Technology Economically
Achievable.
Mine Code K-7 was identified in the draft development
document as the facility exhibiting the very best overall
control and treatment technology for acid or ferruginous
mine drainage. After additional analysis, it was determined
that other mines (namely. Mine Codes A-l, A-ft, and B-2) were-
comparable to mine K-7 in both sophistication of AMD
treatment plant design and efficiency of pollutant
reduction.
As has been mentioned in Section IX, the initial sampling
program conducted during this study did not accurately
represent any possible effects of seasonal variations on
mine drainage treatment facilities. The AMD treatment
facilities included in the winter and spring sampling study
are in the same proximity so as to be equally affected by
weather conditions, and include mine code A-l, A-ft, and B-2.
Mine Code K-7 is not considered to be in the same proximity
as the other mines included in the study. For these
reasons, mine Code K-7 was not included in the winter-spring
sampling program. Mine Codes A-l, A-ft, and B-2 are
recognized as mines exhibiting the very best overall control
and treatment technology.
These mines represent mine drainage treatment facilities
using conventional lime neutralization systems. Settling
basin, mechanical clarifier, or combination of mechanical
clarifier and settling basin are used for suspended solids
removal. All three mines are operated primarily to meet the
effluent requirements of the State of Pennsylvania.
Statistical evaluations of the data generated at these three
mines during the winter and spring sampling program were
performed. This included an evaluation to determine the
maximum .daily concentration of each parameter for each of
the three mines; an evaluation to determine the maximum 30-
-------
day average concentration of each parameter for each of the
three mines; an evaluation to determine the daily maximum
concentration of each parameter at the three mines; and an
evaluation to determine the maximum 30-day average
concentration of each parameter at the three mines.
Best Available Technology Ecnomically Achievable reflects
improved performance at these three mines. The winter-
spring sampling program verified that weather conditions do
not significantly influence the treatment of mine drainage.
Variations in effluent quality were directly attributable to
pH control or maintenance problems which are considered to
be correctable through improved performance at the
individual mine. Those analysis for the days where there
were observed correctable operational problems were not
included in the statistical evaluations.
The effluent limitation guidelines representing BAT for
maximum daily concentrations and 30 day average
concentrations of total iron, dissolved iron, total
aluminum, total manganese, total nickel, and total zinc are
obtainable at any of these three mines 99% of the time with
improved performance related to pH control and improved
maintenance of the mine drainage treatment plant.
Advanced technology for suspended solids reduction has been
demonstrated in the coal industry with flocculant aids and
in other industries such as steel and paper using polishing
filters. Deep bed or in-depth filtration is capable of
achieving effluent suspended solids concentrations on the
order of 10 to 20 mg/1, depending upon the filter media
size, and particle diameter of the solids encountered.
Since this filtration technique has not been demonstrated in
coal industry applications, some leeway is allowed in
establishing BAT suspended solids effluent limitations. BAT
effluent limitation guidelines for suspended solids in the
mining segment of the coal industry is established at 20
mg/1 as a 30-day average value and 10 mg/1 as a daily
maximum value.
The limitation guidelines for "Best Available Technology
Economically Achievable" are presented in Table 35.
It had been considered that Best Available Technology
Economically Achievable could possibly provide for total
dissolved solids control. A study of the available
processes indicates that Reverse Osmosis is the most
applicable. Operating costs for R-o and in particular the
"Neutrolosis Process" were discussed in Section VII and were
estimated at $0.27 per cubic meter ($1.10 per thousand
211
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Parameter
TABLE 35
EFFLUENT LEVELS ATTAINABLE THROUGH APPLICATION OF THE
BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE :
Bituminous, Lignite, and Anthracite
g Services
Coal Storage,
Refuse Storage
• and Coal-Prep-
aration Plant
Ancillary Area
Bituminous, Lignite, and
Anthracite Mfnfng
Coal Preparation
Plant
Acid or Ferrugi-
nous Mine Drainage
Alkaline Mine
Drainage
30 Day Daily 30 Day * Daily * 30 Qiy * Dally * 30 Day * Daily *
Average Maximum Average Maximum Average Maximum Average Maximum
pH
1ROII, TOTAL
DISSOLVED IRON
ALUM MUM,, TOTAL
MANGANESE, TOTAL
NICKEL, TOTAL
ZINC, TOTAL
TOTAL SUSPENDED
«
5«
0
u
£
Q-
<*-
O
-------
gallons) of acid mine drainage treated. For those, mines
that treat acid or ferruginous mine drainage and were
presented as case histories in Section VII, the estimated
operating cost for a Neutrolis system would range from $0,22
to $9.68 per KKG ($0.20 to $8.78 per ton) of coal mined.
The range reflects the age, size and hydrology of the mines.
For mines where drainage volumes are small the operating
cost of a Neutrolosis Process would be low when compared to
the tonnage of coal mined. For those older mines that are
affected by large areas, the volume of mine drainage to be
treated are significantly greater.
The use of reverse osomsis in the treatment of mine drainage
is still in the research stage. while the process shows
some promise, its application has not been successfully
demonstrated at this time. For both technological and
economic reasons, reverse osmosis cannot be recommended as
BAT for the removal of dissolved solids.
Significant recycle or zero discharge is not possible to
obtain for coal mine drainage.
213
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-------
SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
AND PRETREATMENT STANDARDS
INTRODUCTION
The effluent limitations which must be achieved by new
sources, i.e., a sourcer the construction of which is
started after proposal of New Source Performance Standards,
are to reflect the degree of treatment achievable through
application of the best available demonstrated control
technology, processes, operating methods, or other
alternatives. The end result is to identify effluent
standards achievable through the use of improved production
processes (as well as control technology) . A further
determination which must be made for New Source Performance
Standards is whether a standard permitting no discharge of
pollutants is practicable.
Consideration must also be given to:
a. the type of process employed and process changes;
b. operating methods;
c. batch as opposed to continuous operation;
d. use of alternative raw materials and mixes of raw
materials;
e. use of dry rather than wet processes;
f. recovery of pollutants as by-products.
In addition to recommending New Source Performance Standards
and effluent limitations covering discharges into waterways,
constituents of the effluent discharge must be identified
which would interfere with, pass through or otherwise be
incompatible with a well designed and operated publicly
owned treatment plant. A determination must be made as to
whether the introduction of such pollutants into the
treatment plant should be completely prohibited.
It has been determined that technology does exist for
effluent limitations guidelines as proposed for BAT.
However, as previously mentioned, the filtration technology
upon which a portion of BAT suspended solids limitations are
based has not been applied in the coal industry, thus its
215
-------
adaptability, suitability, and economics have not yet been
fully determined. In addition, the degree of reliability
has not been sufficiently demonstrated to merit inclusion in
the consideration of new source performance standards.
The limitation guidelines for "New Source Performance
Standards" are presented in Table 36.
Pretreatment Standards
Wastewaters from the mining industry are not characteristic
of those wastes amenable to treatment by biological
processes. In addition, these wastes are generally not
compatible with sanitary sewage because of their potential
acidic nature, metals content, and large volumes. However,
there are some metalic salts such as aluminum sulfate and
certain ferrous salts which are beneficial to and are used
in waste water treatment at publicly owned treatment
facilities. These metalic salts are commonly used as
coagulants. It has been shown that under controlled
conditions municipal waste water and AMD can be treated
together in "combined treatment." In certain cases AMD may
be an economical source of chemical coagulant, and division
of AMD to "combined treatment" would contribute towards the
abatement of pollution due to AMD.
It is recognized that portions of the Anthracite mining
industry in Pennsylvania have a unique situation in that the
State of Pennsylvania has established ten water sheds which
are affected by mine drainage, and has established a
Pollution Abatement Escrow Fund to build and maintain mine
drainage treatment facilities to treat mine drainage from
active and abandoned mines. Anthracite mining companies
located in these ten water sheds may discharge raw mine
drainage and pay the State of Pennsylvania a fee based on
the tonnage mined. This fee is intended to offset the
operating and maintainence costs of the mine drainage
treatment facilities owned by the State. These state owned
mine drainage treatment* facilities may be considered
publicly owned treatment plants.
216
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TABLE 36
Parameter
Bituminous, Lignite, and Anthracite
Mining Services
Bituminous, Lignite, and
Anthracite Mining
pH
IRON, TOTAL
DISSOLVED IRON
ALUMINUM, TOTAL
MANGANESE, TOTAL
NICKEL, TOTAL
ZINC, TOTAL ,
TOTAL SUSPENDED
SOLIDS
jal Preparation
Plant
3 Day
srage
to
•1-1
rel
Process
M-
o
a
a
u
tn
5
Daily
Maximum
01
•M
ID
5:
in
v>
at
u
o
0
OJ
nj
o
*f—
O
a
Coal Storage,
Refuse Storage
and Coal Prep-
aration Plant
Ancillary Area
30 Day *
Average
6-
3.0
0.30
2.0
2.0
0.20
0.20
35
Daily *
Maximum
6-9
3.5
0.60
4.0
4.0
0.40
0.40
70
Acid or
nous Mine
30 Day *
Average
6-9
3.0
0.30
2.0
2.0
0.20
0.20
35
Ferrugl -
Drainage
Daily *
Maximum'
6-9
3.5
0.60
4.0
4.0
0.40
0.40
70
Alkaline Mine
Drainage
30 Day *
Average
6-9
3.0
,0.30
2.0
2.0
,0.20
0.20
25
Daily
Maximun
6-9
3.5
0.60
4.0
4.0
0.40
0.40
50
*A11 values except pH in rag/1,
-------
-------
SECTION XII
ACKNOWLEDGEMENTS
This document was developed primarily from contractor's
draft reports prepared by Skelly and Loy Engineers and
Consultants. The staff at Skelly and Loy, and at Penn
Environmental Consultants are gratefully acknowledged for
their invaluable assistance in field investigation, water
sample analysis, and the preparation of the draft reports.
Mr. LeRoy D. Loy, Jr. was project manager at Skelly and Loy,
and Mr. Dennis Escher, of Penn Environmental Consultants,
was assistant project manager.
The development of the document and the study supporting the
document was under the supervision and guidance of Mr.
Baldwin M. Jarrett, Project Officer, Effluent Guidelines
Division.
Mr. Allen Cywin, Director, Effluent Guidelines Division, Mr.
Ernst Hall, Assistant Director, Effluent Guidelines
Division, and Mr. Harold Coughlin, Chief, Guidelines
Implementation Branch made invaluable contributions during
the preparation of the document.
Acknowledgement and appreciation is also given to the
editorial assistants, Ms. Darlene Miller and Ms. Linda Rose
for their effort in the preparation of this document.
Appreciation is also given to the secretary, Ms. Laura
Canunarota.
Acknowledgement and appreication is also given to
following organizations, institutions and individuals:
Mining Companies
the
Affinity Mining Company
Altmire Brothers Coal Company
Amax Coal Company
Mr. John Mitchell
Mr. Harold Altmire
Mr. George Hargreaves
Mr. Robert James
Mr. Glenn Kaffenberger
Mr. Jerry Kempf
Mr. Peter Larson
Mr. Alfred M. Lawson
Mr. R. B. Lee
219
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Anaconda Copper
Appolo Fuels Incorporated
Badger Coal Company
Badgett Coal Company
Barbour Coal Company
Barnes & Tucker Company
Bessemer Iron & Coal Company
Bethlehem Steel Corporation
Big Ben Coal Company
Bradford Coal Company
Bridgeview Coal Company
Buffalo Coal Company
C. A. Fisher Coal Company
Carbon Fuel Company
Cedar Coal Company
C. F. & I. Steel Corporation
Mr. John C. Spindler
Mr. T. J. Asher
Mr. Donald Gorman
Mr. junior NewIan
Mr. William Post
Mr. Blane Yeager
Mr. Russell Badgett, Jr.
Mr. Wilson
Mr. Roger Spencer
Mr. Karl Dillon
Mr. M. W. Kearney
Mr. James Smith
Mr. Allen A. Wenturine
Mr. Leroy Carr
Mr. Stephen Alexander
Mr. John P. Billiter
Mr. Thomas P. Conlon
Mr. G. D. Damron
Mr. Bruce E. Duke
Mr. J. L. Gindlesperger
Mr. G. Greer
Mr. David J. Myers
Mr. Garrett Saunders
Mr. A. T. Sosseng
Mr. Richard Stickler
Mr. Lee .Rowland
Mr. Clayton Peters
Mr. Harry Whyel
Mr. Melvin Judy
Mr. Curt Schaffer
Mr. Clarence A. Fisher
Mr. Robert Weaver
Mr. Samuel Quigley
Mr. David Tuckwiller
Mr. A. Pagnotta
220
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Mr. Ed Pearson
Chestnut Ridge Mining Company
Consolidation Coal Company
D 6 L coal Company
Drummond Coal Company
Duguesne Light company
Eagle Coal 8 Dock Company
Ellis Creek Coal 5 Dock Company
Eastern Associated Coal Corp.
Elemar Coal Company
Energy Fuels Corporation
Falcon Coal company
F & D Coal Company, Incorporated
Florence Mining company
Garland Coal & Mining Company
Grays Knob Coal company
Mr. John Peles
Dr. Gm L, Barthauer
Mr. William Bland
Mr, Donald Born
Mr. L. J. Dernoshek
Mr. Steven Halahurich
Mr. Richard A. Htaschka
Mr. James Kantzes
Mr. Jerry Lombardo
Mr. John T. McClure
Mr. Edward Moore
Mr, Bradley Smith
Mr. Richard Schwinabart
Mr. Jack Blankenship
Mr. Jerry Byars
Mr. Bud Long
Mr. John C. Draper
Mr. Roger McHugh
Mr, Thomas pennington
Mr. Reginald Bush
Mr. Marvin Graham
Mr. Stanley Harper
Mr. John T. Higgins
Mr. Kedric Long
Mr. George Mishra
Mr, Reece Slemar
Mr. Robert Adams
Mr. Hillis Everidge
Mr. freeman Saylor
Mr. Robert B. Browning
Mr. Paul Flynn
Mr, Howard Rutherford
Mr. 1« S. Stephens
Mr. Clyde Bennet
221
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Greenwich Collieries
Greenwood Mining Company
Greenwood Stripping Corporation
Grundy Mining company
Gunn-Quealy Coal Company
BarIan Fuel Company
Begins Mining Company
I. C. O.
Indian creek Coal Company
Island Creek Coal company
Jones & Laughlin Steel Corp.
Jude Coal Company
Kaskan Coal Company
Kaiser steel Corporation
Kemmerer Coal company
Kemo Mining Company
Kerry Hears Coal Company
Knife River Coal Mining Company
Mr. John G. Emerich
Mr. James P. Marino
Mr. Bill Valentine
Mr. Frank Voyack
Mr. Andrew Chmel
Mr. Joseph J. Fauzio
Mr. William B. Allison
Mr. James Diamenti
Mr. Herschel Bargo
Mr. Earl Kieffer
Mr. Bro Gordon
Mr. J. B. Parker
Mr. Bliss BlanTcenship
Mr. Rex Blankenship
Mr. Thomas Synder
Mr. Larry Wynn
Mr. H. E, Steinman
Mr. James S. Wasil
Mr. Walter Fall
Mr. George Kaskan
Mr. Lynn Huntsman
Mr. Edward D. Moore
Mr. Louis Engstrom
Mr. Michael zakontnick. Jr.
Mr. Walter Hawkins
Mr. Charles Hears
Mr. Dean Dishon
Mr. Frank Eide
Mr. Thomas A. Gwynn
Mr- A. S. Kane
Mr. H. H. Scherbenski
222
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Xoclier coal company
Lady Jane Collieries Incorporated
LaBosa Fuel company
Lehigh Valley Anthracite
Lone Star Steel
Lovilia Coal Company
Mastellar Coal Company
Mary Ruth Corporation
Mid-continent Coal S Coke Company
Miller-McKnight coal Company
Moran coal company
Mountain Drive Coal Company
M & R Coal company
National Steel Corporation
North American Coal Corporation
Mr. Leon Richter
Mr. Paul D. Hineman
Mr. Charles Merritt
Mr. James LaRosa
Old Ben Coal Company
p. B. s. Coals, Incorporated
Mr. Joseph Pagnotti
Mr. Robert Shober
Mr. James Tedesco
Mr. J. E. Burse
Mr. J. Paul Savage
Mr, Thomas Wignall
Mr. James Watson
Mr. Milford Jenkins
Mr. J. L. Reeves
Mr. J. H. Turner
Mr. Gary McKnighfe
Mr. Donald E. Moran
Mr. James Gibbs
Mr. Lawrence Scott
Mr. William Gadd
Mr. Fred Thicker
Mr. Donald Wills
Mr, Carl Bishop
Mr. c. H. Daub
Mr. Terry Dudley
Mr» Michael Gregory
Mr. Franklin Scott
Mr. Harold Washburn
Mr. C. E, Bailie
Mr. R. E. Flatt
Mr, Lanny Richter
Mr. Walter Von Demfange
Mr. Albright
Mr. Roger Kalaha
Mr. Shirbine
223
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Peabody Coal Company
Peabody Coal Company
Mr. Joseph Whitaker
Mr. Robert Will
Mr. Ziegler
Mr. Ronald Cross
Mr. William Davis
Mr. John Gingrich
Mr. Gene Hendrichs
Mr. Tracy Hendrichs
Mr. James R. Jones
Mr. Thomas Linn
Mr. David G. McDonald
Mr. M. A. McKee
Mr. Ronald Pruett
Mr. Freman Quails
Mr. Wayne Rosso
Mr. Leonard Sautelle
Mr. Harry Yocum
Peter Keiwit Sons1 Mining -Company Mr. Frank Kinney
Mr. J. F. Ratchye
Pittsburgh £ Midway Coal
Mining Company
The Pittston Company
Mr. Charles Atkinson
Mr. J. A. Borders
Mr. Fritz Gottron
Mr. George Hayes
Mr. John C. Willson
Mr. C. R. Montgomery
Premium Coal Company
Queen Anne Coal Company
Rock Creek Mining Company
Pyro Coal Company
Queen Brothers Coal Company
Richland Coal Company
Rochester & Pittsburgh Coal Co.
Rockville Mining Company
Russel Shafer Coal Company
Mr. Robert Swisher
Mr. George Martin
Mr. Robert Queen
Mr. Douglas Blair
Mr. Geroge Kennedy
Mr. J. J. Schaeffer
Mr. Edward Sokal
Mr. Eric Wilson
Mr. Joseph Elliot
Mr. Russel Shafer
224
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Shamrock Coal Company
South-East coal Company
Southern Utah Fuel Company
Surgener's Coal Sales, Incorp.
T. C. H. Coal Company
U. S. Pipe 6 Foundry company
U. S. Steel Corporation
Utah International, Incorporated
Washington irrigation and
Development Company
Western Energy Company
western Hickory Coal Company
West Freedom Mining Corporation
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Arlo Brown
Orville smith
Jack Jenkins
Martinson
Noah Surgener
George E. Neal
Lecil colburn
C. J. Hager
Harold Stacey
John C. Anderson
John W. Boyle
John E. Caffrey
Donald K. Cooper
Herbert Dunsmore
Gregory Ferderber
Robert R. Godard
R. F.: Goudge
Hersch Hayden
M. A.i Holtz
J. A. Kennison
H. E. Kerley
H. E. Ketter
Earl W. Mallick
A. E. Moran
Paul Parfitt
Glen Sides
E. L. Thomas
Paul E. Watson
John E. Young
Leo Hendery
Wayne Sonard
Mr. Richard McCarthy
Mr. Michael Grindy
Mr. W. P. Schmechel
Mr. Martin A. White
Mr. Harold List
Mr. Russell Haller
Mr. John Smith
225
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Westmoreland Coal Company Mr. John Gembach
Mr. Anthony Nevis
Westmoreland Resources Corp. Mr. Ralph E. Moore
Mr. Mathew S. Tudor
White Rock Mining Company Mr. Olaf Shafer
Wyodak Resources Development Mr. Wilford J. Westre
Corporation
Zeigler Coal Company Mr. Coy L. South
Trade organ!zationg
American Mining Congress Mr. Richard C, Beerbower
Mr, Brice O'Brien
Mr. Donald Simpson
Bituminous Coal Research Mr. James F. Boyer, Jr.
Mr. Charles T. Ford
Independent Miners and Mr. Clyde Machemar
Associates
National Coal Association Mr. Joseph W. Mullan
Mr. Robert F. Stauffer
National Independent Coal Assoc. Mr. Louis Hunter
Ohio Mining and Reclamation Assoc.Mr. Neal s. Tostenson
Pennsylvania Coal Mining Assoc. Mr. Franklin H. Mohney
Virginia coal Association Mr. W. Luke Witt
West Virginia Surface Mining and Mr. Daniel Gerkin
Reclamation Association Mr. Ben Lusk
Regulatory Agencies
Atomic Energy commission Dr. Robert L. Spore
Illinois - State of Illinois, Mr. Don Handy
Energy Office, Assistant
226
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Energy Coordinator
Indiana - State of Indiana,
Director, Water Pollution
Control
Kentucky - Dept. of Natural
Resources and Environmental
Protection
MESA (District 7)
Montana - Department of State
Lands, Reclamation Division
North Dakota - North Dakota Dept,
of Health (Director of Water
Supply)
Oklahoma -• Oklahoma Water
Pollution Control
Pennsylvania - Department of
Environmental Resources
Altonna Water Department
Tennessee - Division of Surface
Mining
Tennessee Division of Water
Quality
United States Environmental
Mr. Sam Moore
Mr. Clyde Baldwin
Mr. Kenneth Cobb
Mr. Thomas O. Harris
Mr. William Harris
Mr. William S. Kelly
Mr. Robert Nickel
Mr. Ernest Prewitt
Mr. Kenneth D. Ratliff
Mr. Wensell Sheperd
Mr. Harold Snodgrass
Mr. Robert warrix
Mr. Nevard Wells
Mr. Donald Rheinhardt
Mr. Jerry Spicer
Mr. C. C. McCall
Mr. Roy Koch
Mr. Norman Peterson
Mr. Terry Thurman
Dr. John J. Demchalk
Mr. A. E. Friedrich
Mr. Ernest Giovannitti
Mr. Walter Heine
Mr. Howard A. Luley
Mr. A. E. Molinski
Mr. Mark Roller
Mr. Richard Thompson
Mr* Dave Barr
Mr. Arthur Hope
Mr. Collian Goodlet
Mr. Richard Andrews
227
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Protection Agency
Virginia - Virginia Department
of Reclamation
Virginia Water Control Board
Washington - U. S. Bureau of
Mines (Spokane Mining Research
Center)
Mr. Arthur Chafet
Mr. Elmore Grim
Mr. Gene Harris
Mr. Ronald Hill
Ms. Judith A. Nelson
Mr. John Sceva
Mr. Robert C. Scott
Mr. Robert Scott
Mr. Glen wood D. Sites
Ms. Nancy Speck
Mr. Roger Wilmoth
Mr. William Roller
Mr. Lawrence Owens
Mr. Dallas Sizemore
Mr. Thomas Martin
West Virginia - West Virginia Mr
Department of Natural Resources Mr
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
Mr.
John Ailes
Donald Bailey
Joseph Beymer
Don E. Caldwell
Owen L. Carney
James Gillespie
Benjamin Greene
Robert McCoy
Thomas Methaney
William Raney
Jerry Starcher
Basil Sweeney
Educational Institutions
Colorado State University
Montana state University
Pennsylvania State University
University of Tennessee
West Virginia University
Dr. David McWhortor
Dr. Richard Hodder
Dr. Harold Lovell
Dr. Roger A. Minear
Dr. John R. Moore
Dr. G. Lansing Blackshaw
228
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SECTION XIII
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Dutcher, Russell R., and others. Mine Drainage Part li
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EPA, Wastewater Filtration, Design Consideration, Technology
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Falkie, Dr. Thomas V. "Overview of Underground Refuse
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Ford, C. T., and Boyer, J. F. Treatment of Ferrous Acid
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Frank, V. F. and Gravenstreter, J. P., "Operating Experience
with High-Rate Filters," WPCF Journal, 41, 2, 292,
February, 1969.
Gaines, Lewis, and others. "Electrochemical Oxidation of
Acid Mine Waters," Fourth Symposium on coal Mine
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Gang, Michael W., and Langmuir, Donald. "Controls on Heavy
Metals in Surface and Ground Waters Affected by Coal
Mine Drainage; Clarion River - Redbank Creek Watershed,
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Goddard, R. R. "Mine Water Treatment -- Frick District,"
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Haines, G. F. and Kostenbader, P. D. "High Density Sludge
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232
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ORSANCO, May. 1970.
Hall, Ernst P. "Effluent Limitation Guidelines and
Standards," Fifth Symposium on Coal Mine Drainage
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234
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236
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1974,
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U. S. Department of the Interior. Study of_ Strip and
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U. S. Department of the Interior. Sul-biSul Ion Exchange of
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U- S. Department of the Interior. Surface Mining and Our
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VTN Environmental Sciences. Environmental Analysis for
Decker Coal Company, Mine Decker, Montana. Irvine,
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Van Voast, Wayne A. Hydrologic Effects of S_trjp coal Mining
in Southeastern Montana - Emphasis; One Year of Mining
Near Decker. Butte, Montana: Montana College of
Mineral Science and Technology, 1974.
Wahler, William A. "Coal Refuse Regulations, Standards,
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Preparation Plant Refuse Disposal. Washington: National
Coal Association, 1974.
Wallace, J. T., "Progress Report on Ultra-High Rate
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240
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Westinghouse Electric Corporation. Wi 1 ke s - Bar re Deminer^l-
giant -ii- • Cgst of Water Report , Report to
Pennsylvania "Department of Environmental Resources,
1971.
West Virginia University, Morgan-town, West Virginia.
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wilmoth Roger c. Ajoglication of Reverse osmosis to Acid
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U.S. Government Printing Office, 1973.
Wilmoth, Roger C. jLiniestone and Limestone- Lime-
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Wilmoth, Roger C., and Hill, Donald D. Mine Drainage
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Institute of Mining, Metallurgical and Petroleum
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wilmoth, Roger c. and others. "Treatment of Ferrous Iron
Acid Mine Drainage by Reverse Osmosis," Fourth Symgosium
on Coal Mine Prainage Ses:eafgh. Pittsburgh,
Pennsylvania: Coal Industry Advisory Committee to
QRSANCQ, 1972.
Wilmoth, Roger C. , and others, "Combination Limestone-Lime
Treatment of Acid Mine Drainage," Fourth symposium on
Coal Mj.ne Drainage Research . Pittsburgh, Pennsylvania;'
Coal Industry Advisory Committee to ORSANCO, 1972.
Wykoff, R. 8., "Major Filtration Development at New Steel
Mill,1* Industrial Waste, August, 1970, p, 8-10.
Yeh, S., and Jenkins, C. R. "Disposal of Sludge from Acid
Mine Water neutralization," Journal Water Pol lu t ion
control Federation. Vol. 53, No. fl, (1971), pp. 679-
688.
241
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Zabban, W., and others. "'Conversion of coal-Mine Drainage
to Potable Water by Ion Exchange,11 Journal AWWA. Vol.
64, No. 11, November 1972.
Zaval, F. J., and Robins, J. D. Rev-egetation Augmentation
by Reuse of Treated Active Surface Mine Dra.inaqre - A
Feasibility sttady* D.S. Environmental Protection Agency
Research Series 14010 HNS, 1972.
242
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SECTION XIV
GLOSSARY
AMD - Acid Mine Drainage
Aeration - The act of exposing to the action of air, such
as, to mix or charge with air.
Anion - An ion that moves, or that would move, toward an
anode. Negative ion.
Anticline - A fold that is convex upward. The younger
strata are closest to the axial plane of the fold.
Aquifer - Stratum or zone below the surface of the earth
capable of producing water as from a well.
Auger - Any drilling device in which the cuttings are mech-
anically and continuously removed from the borehole without
the use of fluids.
Backfilling - The transfer of previously moved material back
into an excavation such as a mine or ditch, or against a
constructed object.
Bench - The surface of an excavated area at some point
between the material being mined and the original surface of
the ground on which equipment can set, move or operate. A
working road or base below a highwall as in contour
stripping for coal.
Cation - An ion that moves, or that would move, toward a
cathode. Positive ion.
Clarifier - A device for removing suspended solids.
Coal Preparation Plant - A facility where coal is crushed,
screened, sized, cleaned, dried, or otherwise prepared or
loaded prior to the final handling or sizing in transit to
or at a consuming facility.
Deep Mine - An underground mine.
Dissolved Solids - The difference between the total and
suspended solids in water.
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Drift. - A deep mine entry driven directly into a horizontal
or near horizontal mineral seam or vein when it outcrops or
is exposed at the ground surface.
Ecosystem - A total organic community in a defined area or
time frame.
Erosion - Processes whereby solids are removed from their
original location on the land surface by hydraulic or wind
action•
Flume - An open channel or conduit on a prepared grade.
Ground Water Table (or Level) - Upper surface of the under-
ground zone of saturation.
Grout - A fluid mixture of cement, sand (or other additives)
and water that can be poured or pumped easily.
Grout Curtain - Subsurface zone of greatly decreased permea-
bility created by pressurized insertion through boreholes of
cement or other material into the rock strata.
Highwall - The unexcavated face of exposed overburden and
coal in a surface mine or the face or bank on the uphill
side of a contour strip mine excavation.
Hydrology - The science that relates to the water systems of
the earth.
mq/1 - Abbreviation for milligrams per liter which is a
weight to volume ration commonly used in water quality
analysis. It expresses the weight in milligrams of a
substance occurring in one liter of liquid.
Mulching - The addition of materials (usually organic) to
the land surface to curtail erosion or retain soil moisture.
Neutralization - The process of adding on acid or alkaline
material to waste water to adjust its pH to a neutral
position.
Osmosis - The passage of solvent through a membrane from a
dilute solution into a more concentrated one, the membrane
being permeable to molecules of solvent but not to molecules
of solute.
Outcrop - The surface exposure of a rock of mineral unit.
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Overburden - Nonsalable material -that overlies a mineable
mineral.
Oxidation - The removal of electrons from an ion or atom.
PermeabjJ.ity - The measure of the capacity for transmitting
a fluid through a substance.
pH - The negative logarithm to the base ten of the hydrogen
ion concentration. pH 7 is considered neutral. Above 7 is
basic - below 7 is acidic.
Point source - 'Shy discernible, confined and discrete
conveyance, including but not limited to any pipe, ditch,
channel, tunnel, conduit, well, discrete fissure,
container, rolling stock, concentrated animal feeding
operation, or vessel or other floating craft, from which
pollutants are or may be discharged.
Raw Mine Drainage - Untreated or unprocessed water drained,
pumped or syphoned from a mine.
Reclamation - The procedures toy which a disturbed area can
be reworked to make it productive, useful, or aesthetically
pleasing.
Re_gr§ding - The movement of earth over a surface or depres-
sion to change the shape of the land surface.
Riprap - Rough stone of various sizes placed compactly or
irregularly to prevent erosion.
Runoff - That part of precipitation that flows over the land
surface from the area upon which it falls.
scarification - Decreasing the smoothness of the land
surface.
Sediment - Solid material settled from suspension in a
liguTd "medium. ' . -
Sludge - The precipitant or settled material from a waste-
water,
Sludge Density - A measure of solids contained in the sludge
in relation to total weight.
Scdubilijby Product - The equilibrium constant for the
process of solution of a substance (usually in water). The
higher the value, the more soluble the substance.
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Spoil Material - The waste material removed from a mine
facility that is not considered useful product.
Stratigraphy - The science of formation, composition,
sequence and correlation of stratified rocks.
Subsidence - The surface depression created by caving of the
roof material in an underground mine.
Suspended Solids - Sediment which is in suspension in water
but which will physically settle out under quiescent condi-
tions (as differentiated from dissolved material) .
Syncline - A fold that is concave upward. The younger
strata are closest to the axial plane of the fold.
Tectonic Activity - Deformation of the earth's crust
resulting from vertical and horizontal movement.
\
Terracing - The act of creating horizontal or near
horizontal benches.
Turbidity - Is a measure of the amount of light passing
through a volume of water, which is directly related to the
suspended solids content.
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Table 37
CONVERSION TABLE
MULTIPLY (ENGLISH UNITS) by TO OBTAIN (METRIC UNITS)
ENGLISH UNIT ABBREVIATION CONVERSION ABBREVIATION METRIC UNIT
acres ac
acre-feet acft -l
British Thermal
Units BTU
British Thermal
Units/pound BTU/lb
cubic feet cuft
cubic feet cu fl
cubic feet/minute cfm
cubic feet/second cfs
cubic inches cu in.
cubic yards cu y
degrees Fahrenheit °F
feet ft
flask of mercury (76.5 Ib)
gallons gal
gallons gal
gallons/day gpd
gallons/minute gprn
horsepower hp
inches in.
inches of mercury in. Hg
mfles (statute) mi
million gallons/day mgd
ounces (troy) troy oz
pounds Ib
pounds/square
inch (gauge) psig
pounds/square
inch (gauge) psig
square feet sq ft
square inches sq in.
tons (short) t
tons (long) long t
yards y
1 Actual conversion, not a multiplier
0.405
1 ,233.5
0.252
0.555
0.028
2832
'0.028
1.7
16.39
0.76456
0.555 (OF-32)1
0.3048
34.73 l
0.003785
3.785
0.003785
0.0631
.0.7457
2.54
0.03342
1.609
3,785 !
31.10348
0.454
(0.06805 psig -H)1
5.1715
0.0929
6.452
0.907
1.016
0.9144
ha
cum
kgcal
kg cal/kg
cu m
1
cu m/min
cum/min
cu cm (or cc)
cu m
°C
m
kgHg
cu m
1
cu m/day
I/sec
kW
cm
atm
km
cum/day
g
kg
atm
cmHg
sqm
sqcm
fckg
kkg
m
hectares
cubic meters
kilogram - calories
kilogram calories/kilogram
cubic meters
.liters
cubic meters/minute
cubic meters/minute
cubic centimeters
cubic meters
degrees Celsius
meters
kilograms of mercury
cubic meters
liters
cubic meters/day
liters/second
kilowatts
centimeters
atmospheres
kilometers
cubic meters/day
grams
kilograms
atmospheres (absolute)
centimeters of mercury
square meters
square centimeters
metric tons (1000 kilograms)
metric tons (1000 kilograms)
meters
247
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