United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
EPA-600/7-81-022
March 1981
Research and Development
vvEPA
User's Manual for
Premining Planning of
Eastern Surface
Coal Mining
Volume 5
Mine Drainage
Management and
Monitoring
Interagency
Energy/Environment
R&D Program
Report
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EPA 600/7-81-022
March 1981
USER'S MANUAL FOR PREMINING PLANNING OF
EASTERN SURFACE COAL MINING
Volume 5: Mine Drainage Management and Monitoring
by
Harold L. Lovell, Richard Parizek
Donald Forsberg, Deborah Richardson, Arlene Weiner
Department of Mineral Engineering
and Department of Geosciences
The Pennsylvania State University
University Park, Pennsylvania 16802
Grant No. R803882
Project Officer
John F. Martin
Energy Pollution Control Division
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
ii
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution
control methods be used. The Industrial Environmental Research Laboratory-
Cincinnati (lERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and economically.
This volume is the fifth in a series of six reports designed to provide
the surface coal mining industry and its regulators with a comprehensive
review of the best available methods for extracting this valuable mineral
resource while protecting the fragile environment. This report aims to
provide a technical background on which to establish pragmatic guidelines
for directing decisions regarding water quality management in surface mining.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
iii
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ABSTRACT
This volume is the fifth in a series of six reports designed to provide
the surface coal mining industry and its regulators with a comprehensive
review of the best available methods for extracting coal while protecting the
fragile environment. Recommendations for selecting and designing mining
systems were based on a review and critical evaluation of the methods re-
ported in the literature and applied in the field. The six-volume report
examines the surface mining of coal in the Eastern United States and sets
guidelines for developing, evaluating, and selecting mining and reclamation
plans that will be the least detrimental to the environment. The scope of
the study was to consider the geological and hydrological settings before
mining as basic inputs to premining planning, and to develop guidelines for
assessing alternatives in the areas of surface mine engineering, water man-
agement, and mine land planning.
Volume 5 is concerned with mine drainage management and monitoring.
The objective of the report is to provide a technical background on which to
establish pragmatic guidelines for making decisions regarding water quality
management in surface mining. This report is divided into four major areas
of concentration. The first area provides a general overview of the problem
of mine drainage control and the nature of mine drainage water. The second
area presents a review of techniques commonly used for drainage abatement
and water quality control in surface mining. The third area examines a
number of experimental techniques currently being considered as having some
potential for controlling mine drainage water. The fourth area reviews the
various aspects of the monitoring programs.
This report was submitted in fulfillment of Grant No. R803882 by the
Department of Mineral Engineering and the Department of Geosciences of The
Pennsylvania State University under the sponsorship of the U.S. Environmental
Protection Agency. The report covers the period July 1, 1975, to May 30,
1978, and work was completed as of June 1, 1978.
iv
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CONTENTS
Foreword
Abstract ............................... 1V.
Figures ............................... vl
Tables ................................ *
Abbreviations ............................
Acknowledgments ...........................
Project Staff ............................
1. Introduction ........................ -~
Contact of waters with disturbed mineral surfaces ... 2
Length of treatment .................. 2
Cost considerations ..................
Site characteristics .................. ^
Transportation, storage, and coal preparation ..... 5
2. Summary and Conclusions ................... 9
Steps in premining planning .............. °
Approaches to water quality control .......... 10
Basic elements of water quality control ........ 12
3. Overview of the Mine Drainage Control Problem ........ 13
Relationship of geographical trends to water
quality management .................. 13
Origin and quality of water encountered in surface
mining ........................ 1"
Legal aspects of mine drainage control ......... 27
4. Common Approaches to Mine Drainage Abatement and Water
Quality Control ...................... 39
Control of water movement as related to water quality . . 39
Mine drainage control actions based on the nature of
the overburden .................... 57
Utilization of settling ponds ............. 66
Treatment of waters associated with surface mining ... 78
5. Experimental Techniques for Treating Surface Mine Waters . . 95
Overview ........................ 95
Physical/chemical plant processes ........... 95
Chemical field methods ......... . ....... 96
Physical field methods
6. Monitoring Programs
Introduction
Monitoring wells .................... 12'
Soil water ....................... I28
Long-term changes in precipitation ........... 132
References .............................. 139
Glossary ............................... I50
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FIGURES
Number Page
1 Rock boulders at toe of valley fill area grading to
sedimentation basin 3
2 Valley fill showing water discharge rock core 3
3 Haulroad culverts discharging surface waters at high
velocities 6
4 Diversion ditch sump along haulroad showing use of
standpipe 6
5 Coal preparation plant slimes being dewatered in surface
mine operations 7
6 Coal preparation plant refuse slimes being built in
surface mine 8
7 Distribution of U. S. bituminous coals by
geological province and sulfur
content 14
8 Continuous erosion from a reclaimed surface coal mining
operation 17
9 Aquifer drainage from highwall of Pennsylvania surface
coal mine 22
10 Fields of stability for solid and dissolved forms of iron ... 23
11 Fields of stability for solid and dissolved forms of
manganese 24
12 Areas of moisture surplus and deficiency in the United
States and the basis of water rights in various states ... 30
13 Use of riprap in waterways to dissipate flow energies and
protect channels 41
vi
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FIGURES (Continued)
Number Page
14 Use of riprap in waterways to dissipate flow energies and
protect channels, and use of half-round metal pipes and
concrete structures to divert surface runoff across
surface mines ........................ 41
15 Slope reduction measures using sloped benches, reverse
benches, and concave slopes ................. 43
16 Diversion ditches placed below coal crop to control surface
runoff, groundwater runoff, and siltation .......... 44
17 Spray application of chemical sealant on side/bottom
surfaces of a coal settling basin .............. 46
18 Ponding areas resulting from incompletely restored backfill
procedures ......................... 47
19 Average annual evaporation (inches) from shallow
lakes ............................ 53
20 The use of recharge wells and clay cutoff barriers to
control drawdown within aquifers adjacent to surface mines
and to reduce inflow, pumpage, and treatment requirements . . 55
21 Sheet piles and grout cutoff curtains used in unconsolidated
overburden deposits to maintain groundwater levels during
and following mining .................... 56
22 Plot of pH through time for the treatment site ........ 67
23 Plot of sulfate concentration through time for the
treatment site ....................... 68
24 Plot of acidity through time for the treatment site ...... 69
25 Plot of alkalinity through time for the treatment site .... 70
26 Plot of sulfate load through time for the treatment site ... 71
27 Fresh water samples in jars ready for testing ......... 75
28 Settling rate measurements of flocculated suspended
solids ........................... 76
29 Settling rate curve used in studying the application of
flocculants ......................... 77
vii
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FIGURES (Continued)
Number Page
30 Flocculated surface waters after clarification from
surface mining operation in the State of Washington 79
31 TraDet hopper and slime used to neutralize mine drainage
in surface coal mines 82
32 Hopper and metering device for introducing hydrated lime into
coal mine drainage 83
33 Ponded mine drainage designed to cultivate the growth of
iron-oxidizing bacteria as a water treatment operation ... 85
34 Solid/fluid settling basins to remove sludge from lime-
treated surface mine drainage 87
35 Effect of dilution on the pH of mine waters when mixed
with bicarbonate-free water with a pH of 7 88
36 The combined effects on mine water pH of dilution and
buffering by mixing with bicarbonate solutions of six
different concentrations 90
37 Limestone and calcareous shale placed on top of acid-producing
strata to impede acidic reactions 92
38 Glacial drift overburden is placed upon bed rock spoil:
the unleached Z5 horizon impedes acid reactions
within underlying rock spoil deposits 93
39 Thin, blocky limestone beds crushed to increase surface area
and placed above acid-producing mine spoil and coal plant
preparation wastes 94
40 Natural abatement of acid mine drainage where acidic
groundwaters come into contact with calcareous soils .... 98
41 Application of acid mine drainage to calcareous soils
by spray irrigation and flooding methods 99
42 Comparison of pH for acid mine water and Guernsey and Rayne
column effluents 101
43 Total acidity or alkalinity of acid mine drainage and
Guernsey and Rayne soil column effluents ... 101
44 Aluminum content of acid mine water and Rayne soil
column effluents 103
viii
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FIGURES (Continued)
Number Page
45 Manganese content of acid mine water and Rayne soil
column effluents 104
46 Zinc content of acid mine water and Guernsey and Rayne
soil column effluents 105
47 Copper content of acid mine water and Guernsey and
Rayne soil column effluents 105
48 Potassium content of acid mine drainage and Guernsey
and Rayne soil column effluents 107
49 Calcium content of acid mine drainage and Guernsey and
Rayne soil column effluents 107
50 Barren, acid-producing spoil that fails to support
vegetation and revegetation of the same spoil
following treatment by sewage sludge 109
51 Reclaimed surface mine with vegetated area and contouring
to provide safe pond slopes for large animals 119
52 Connector wells used to reduce inflow of groundwater to
surface mines 120
53 Alkaline groundwater contained in deep aquifers underlying
acid-mine-drainage-producing mines lacking other
sources of alkalinity 124
54 Monitoring well placed above groundwater flow channels
containing mine drainage 129
55 Monitoring wells placed below groundwater flow channels
containing mine drainage 130
56- Fracture zones causing mine drainage to bypass monitoring
wells
57 Pressure-vacuum lysimeters used to obtain water within
the zone of aeration above the water table 133
58 Predicted pH of precipitation over the eastern United States
during the period 1955-56 136
59 Predicted pH of precipitation over the eastern United States
during the period 1965-66 137
IX
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TABLES
Number Page
1 Summary of Composite 1.60 Specific Gravity Product
Analysis, by Region , 15
2 Effluent Limitations Under Title 40, Part 434, of the
Clean Water Act of 1977 (Coal Mining Point Sources) 27
3 Summary of Water Rights for the Appalachian Region 31
4 Summary of Water Rights for the Eastern Interior Region .... 34
5 Summary of Water Rights in the Western Interior Region .... 35
6 Monthly and Annual Evapotranspiration in Inches of Water
Over Hadley Creek Basin, Illinois, 1956-58 49
7 Monthly and Annual Evapotranspiration in Inches of Water
Over Panther Creek Basin, Illinois, 1951-52 and 1956 .... 50
8 Monthly and Annual Evapotranspiration in Inches of Water
Over Goose Creek Basin, Illinois, 1955-58 51
9 Selected Chemical Properties of Rayne and Guernsey Soils . . . 102
10 Average Concentrations of Constituents in the Sewage
Effluent and Sludge Used in the Pennsylvania State
Demonstration Project 110
11 Fertilizer Equivalents of Effluent and Sludge Treatments . . . 110
12 Tree Seedling Survival Rates Ill
13 Average Height Growth of Surviving Tree Seedlings Ill
14 Average Effluent Concentrations of pH, Fe, and Al 112
15 Average Effluent Concentrations of P, NO -N, Org-N, K, Ca,
Mg, Na and Mn 112
16 Grain-Size Distribution for Three Codes of Valentine Limestone
Provided by the Marblehead Limestone Company 115
17 Chemical Water Quality Data Obtained Above and Below the
Limestone Barrier 117
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ABBREVIATIONS
APHA — American Public Health Association
ASTM — American Society for Testing and Materials
atm — atmosphere
cfs — cubic feet per second
cm — centimeter
Eh — oxidation potential
EPA — U.S. Environmental Protection Agency
FHA — Federal Highway Administration
ft -- foot
h — hour
in — inch
kg — kilogram
km — kilometer
H — liter
a/sec — liters per second
m — meter
NCA — National Coal Association
NWC — National Water Commission
Pa — Pennsylvania
PennDOT — Pennsylvania Department of Transportation
PSU — The Pennsylvania State University
s — second
USBM — U.S. Bureau of Mines
XI
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ACKNOWLEDGMENTS
This report was prepared for the U.S. Environmental Protection Agency,
Energy Pollution Control Division, Industrial Environmental Research
Laboratory, Cincinnati, Ohio. Special thanks are extended to Mr. John F.
Martin, who served as project officer.
The materials presented here represent a joint effort by the Department
of Mineral Engineering and the Department of Geosciences of the College of
Earth and Mineral Sciences, The Pennsylvania State University. The work
performed in the preparation of this report was under the direction of
Dr. H. Lovell of the Mineral Engineering Department, who provided the overall
structure of the report. He was assisted by Mr. D. Forsberg, Ms. D.
Richardson, and Ms. A. Weiner, graduate assistants in Mineral Engineering.
The efforts of the Geosciences group were directed by Dr. R. R. Parizek, who
was assisted by Ms. J. Herman, research assistant in Geosciences. Mr. M. Clar,
research assistant in Mining Engineering, acted as project coordinator and
assisted in integrating the efforts of the two groups and editing of the
final report.
Financial support for the completion aspects of the work performed by
the Geosciences group was provided by the Mineral Conservation Section,
The Pennsylvania State University. Principal funding was provided by EPA
Grant No. R803882.
xii
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PROJECT STAFF
The materials contained in the manual were prepared by an interdepart-
mental and interdisciplinary group of the College of Earth and Mineral
Sciences of The Pennsylvania State University. Overall management for the
project was provided by the Department of Mineral Engineering. The project
staff was comprised of the following personnel:
Dr. R. V. Ramani
Professor of Mining Engineering
Dr. L. W. Saperstein
Professor of Mining Engineering
Dr. H. L. Lovell
Professor of Mining Engineering
Dr. R. R. Parizek
Professor of Geology
Dr. C. G. Knight
Associate Professor of Geography
Dr. R. Stefanko
Professor of Mining Engineering
Prof. R. L. Frantz
Professor of Mining Engineering
M. L. Clar
Research Assistant in Mining
Engineering
L. B. Phelps
Instructor in Mining Engineering
C. J. Bise
Instructor in Mining Engineering
P. J. Duhaime
Graduate Assistant in Geography
D. Forsberg
Graduate Assistant in Mining
Engineering
- Project Manager and Co-Principal In-
vestigator (Surface Mining Engineering,
Land Use Planning, Mine Planning)
- Co-Principal Investigator (Federal
and State Laws and Regulations, Land
Use Management)
- Co-Principal Investigator
(Water Quality Management)
- Faculty Associate
(Geology and Hydrology)
- Faculty Associate
(Land Use Management)
- Faculty Associate
(Project Consultant)
- Faculty Associate
(Project Consultant)
- In-House Project Co-ordinator
- Surface Mine Engineering
- Surface Mine Engineering
- Land Use Management
- Water Quality Management
xiii
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K. W. Grubaugh - Laws and Regulations
Graduate Assistant in Mining
Engineering
C. Murray - Mining Engineering
Graduate Assistant in Mining
Engineering
D. Richardson - Water Quality Management
Graduate Assistant in Mining
Engineering
J. Sgambat - Geology
Graduate Assistant in Geology
A. Weiner - Water Quality Management
Graduate Assistant in Mining
Engineering
xiv
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SECTION 1
INTRODUCTION
Volume 5 Is part of a six-volume series of reports designed to provide
the surface coal mining industry and its regulators with a comprehensive re-
view of the best available arid least environmentally detrimental methods for
extracting coal. This volume is concerned with the water quality management
aspects of surface coal mining practice in the Eastern United States. The
specific study region is defined in Volume I, the executive summary. The
objective of this report is to provide a technical background on which to
establish pragmatic guidelines for making decisions regarding water quality
management in surface mining. Related aspects concerned with water volume
are considered separately in Volume 4, Mine Hydrology. Because it is very
difficult to separate the qualitative and quantitative aspects of water
resources management, some degree of overlapping exists between Volumes 4
and 5 of this manual. Consequently, the user is advised to refer to these
two volumes jointly.
The estimated amount of coal recoverable in the United States by surface
mining* has increased through the years (U.S. Bureau of Mines, 1971), pri-
marily because of the availability of larger equipment (Haley, 1974). How-
ever, the potential advantages of economic coal recovery using larger
stripping ratios are accompanied by additional economic and technical con-
siderations, especially environmental problems. Firmer mining regulations
regarding water effluents for point sources (Coal Mining Operating Regu-
lations, 1976) and recently developed nonpoint source philosophy (U.S.
Environmental Protection Agency, 1976) have better defined these problems.
Water quality aspects of surface mining frequently become complex and chal-
lenging, creating problems that potentially supersede those of direct control
of the overburden and surface reclamation.
The extent of permissible water degradation occasioned by surface mining
is defined by law (Coal Mining Operating Regulations, 1976; Coal Mining
Effluent Guidelines and Standards, 1977; and U.S. Environmental Protection
Agency, 1976). Though the goal may be to cause no change in water quality as
a result of surface mining, temporary and minimal water quality degradation
may be unavoidable if these critical energy resources are to be exploited for
current societal demands. The achievement of the control technically pos-
sible, like most environmental problems, results in increased direct costs;
but if water degradation were to continue unchecked, indirect reclamation
*The 1974 reserve base was 173 billion tons (Averitt, 1975; Dupree, et al.,
1976), but it represented less than 30 percent of the total coal reserves
when expressed on a calorific basis.
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costs could be even greater. Accordingly, optimal economic water quality
control must be attained, or the cost of deriving energy from coal will work
to the disadvantage of the individual and the nation. This report reviews
man's technological capability and the economic implications of managing
water quality during surface mining using procedures that coordinate pollu-
tion control with the engineering aspects of coal mining.
This volume is divided into four main areas: (1) an overview of the
mine drainage control problem, (2) common techniques used for drainage abate-
ment and water quality control, (3) experimental drainage abatement tech-
niques, and (4) monitoring. A few of the basic considerations that must be
part of any mine drainage control program are discussed briefly in this
section.
CONTACT OF WATERS WITH DISTURBED MINERAL SURFACES
The modification (usually quality degradation) of prevailing water
quality by surface mining results from the dispersion, reaction, and solution
of mineral components by the water as a consequence of the disruption of sur-
face and near-surface strata equilibria by the mining process. Prevention of
water quality degradation must be based on measures to avoid or minimize con-
tact of the waters with the disturbed mineral surfaces. Only trace levels of
grease, oils, debris, or explosive residuals are, unavoidably, added to the
waters directly from the mechanical operations.
LENGTH OF TREATMENT
Situations exist where adequate water quality control can be achieved
only by continuous water treatment before release to surface streams. These
actions may be necessary over long periods of time and should be avoided and/
or minimized, if possible.
COST CONSIDERATIONS
The water quality control cost levels are generally higher in the
Eastern United States for several reasons. Seams are thinner, and the ratio
of acreage disturbed to coal recovered is greater. There is a tendency to
have overburden that is more highly acidic in the East, a condition that
enhances the degradation of water quality. In addition, the more abundant
precipitation accelerates acid reactions, and the population density of this
area justifies the protection of water sources from physical and chemical
damage.
Traditional surface mine operations have tended to ignore control of
water quality or viewed it as an expensive nuisance. The cost of providing
for adequate treatment of mine waters should be considered in the initial
mining feasibility study. Special techniques may be necessary in certain
instances (such as compaction of overburden and placement of rock barriers
for erosion control, Figures 1 and 2) that greatly increase project costs.
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Figure 1. Rock boulders at toe of valley fill area
grading to sedimentation basin. Concrete
spillway from basin provides for high
water levels.
Figure 2. Valley fill showing water discharge rock core,
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Premining plans must go beyond the requirements of the permit applications to
coordinate the control of potential water pollution with the development of
mining systems. Inadequate premining environmental planning and failure to
take appropriate actions during mining can lead to intolerable treatment
costs, environmental degradation, long-term treatment requirements, and even
legal actions.
SITE CHARACTERISTICS
Topography
The surface mining practices in the study area have been classified
(Skelly and Loy, 1975) into three groups based on regional topography:
(1) Steep slopes with contour mining along the outcrop. These locations may
be least vulnerable to water quality changes, but most susceptible to silta-
tion problems (Hittman Associates, 1976). (2) Rolling terrain with modified
area and multiple-cut contour mining. Since these operations occur below
hill crowns and interrupt aquifer-groundwater tables, they can be conducive
to larger water flows and quality changes. (3) Flat terrain with thick
overburden and box-cut area mining. The depth of these cuts commonly dis-
rupts large, more regional aquifers, implicating large volumes of slow-moving
groundwaters. The mineralogy and geochemistry of the strata (pyrite vs.
alkaline minerals) subsequently become critical factors in water quality
changes. The potential for water quality change is great.
Geology
Consideration must be given to the local geology (Caruccio and Ferris,
1974; see also Volume 4 of this report, Mine Hydrology), including
stratigraphy, mineralogy, groundwater pollution potential, and flow levels.
Detailed mapping should be conducted to establish topography, subsurface and
surface water flows, and lineament-fracture traces and other water-con-
trolling structures. Plans must be established in advance for surface water
control, water pollution prevention and treatment techniques, and backfilling
and surface reclamation procedures.
Site exploration relies heavily on coal outcrop observations and docu-
mented regional geology. Specific drilling data collection procedures vary
from scattered and random drill holes to detailed grid patterns. Unfor-
tunately, the acquisition of water level, flow rate, and quality data during
these drilling operations is not common; nor is detailed evaluation of cores
for strata identification and water pollution potential. Core samples should
be examined for pyrite and alkalinity characterization, as well as for other
measures indicative of water pollution potential. These core samples often
are the only data source for planning coal beneficiation operations, in-
cluding estimation of quantities and characteristics of refuse reject. These
data provide a useful guide for water quality management. Geophysical
logging techniques such as gamma-gamma density logs, natural gamma ray logs,
neutron logs, and resistivity have only recently been introduced into coal
site exploration and offer potentially powerful contributions. Exploration
samples should be subject to topsoil evaluation, which is critical in
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reclamation and revegetation. These concerns extend to edaphology and the
nature of the soils and their fertility. Such data become helpful in the
planning of topsoil replacement following its temporary storage. Current
soil reference sources that should be consulted for details include Taylor
and Ashcroft, 1972; Brady, 1974; Tisdale and Nelson, 1975; Jackson, 1970;
and Black, 1965. Aerial remote sensing can be used to establish the lo-
cations of concentrated soils and groundwater flows, regions of increased
permeability, and significant hydraulic head changes within structures
revealed by lineaments and fracture traces (Lovell and Gunnet, 1974; see
also Volume 3 of this report, Geology of Eastern. Coalfields, and Volume 4,
Mine Hydrology).
TRANSPORTATION, STORAGE AND COAL PREPARATION
Related coal mining activities such as transportation, storage of min-
eral products, and coal preparation can contribute to water pollution
problems. A detailed discussion of these associated problems is beyond the
scope of the report, but general considerations will be presented.
Transportation of surface-mined coals is not normally a major problem
with respect to water quality. If special haul roads are constructed, these
roads must be properly designed to collect surface runoff and release it
without causing environmental degradation. Frequently, culverts carrying
surface runoff in high-slope areas release their flow directly at lower
elevations at high velocities (Figure 3). Such discharges should be
released via check sumps at lower velocities to prevent erosion (Figure 4).
Pipeline transport of coal is not currently applied in the study region,
but it may become important. Careful control of water quality is necessary
in this process, as is the definition of the surface water or groundwater
supply sources that can sustain these prolonged water demands and the dis-
posal or use of this water at the point of discharge.
The storage of surface-mined coal poses special problems in water
quality management, especially those related to surface runoff. The avail-
ability of water resources for the study region is discussed in Volume 3
of this series, Geology of Eastern Coalfields. Occasionally in surface
mining, bin or silo storage is practised which offers the greatest pro-
tection against degradation of water by drainage from mined coal. Primary
control procedures for stockpiled coal involve diversion of water from the
stockpile and collection of surface runoff waters around the storage area
and their direction to settling basins for sedimentation and chemical
treatment, if necessary. Potential water infiltration to the subsurface
under a coal storage pile should not be ignored, as such infiltration can
serve as a diffuse source of pollution.
Effluents from coal preparation facilities and ancillary areas are
strictly regulated by current effluent guidelines (Coal Mining Effluent
Guidelines and Standards, 1977) limiting iron, manganese, and total sus-
pended solid concentrations and the pH of the water. These requirements may
necessitate the construction of treatment facilities or the design of a
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Figure 3. Haulroad culverts discharging surface waters at high velocities.
Figure 4. Diversion ditch sump along haulroad showing use of standpipe.
6
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closed-circuit water system. Burial of coal refuse from the preparation
plant with the overburden during backfilling should be accomplished in
accordance with good water quality management practices to minimize the
potential for water pollution (National Coal Association, 1974). The
handling of preparation plant slime flows is sometimes coordinated with
surface mine refuse disposal (Figure 5 and 6). Volume 4 stresses that the
disposal of these wastes frequently results in a pollution problem from
mines that lacked sources of alkalinity and that might otherwise have pro-
duced acceptable water quality. Care should be exercised when selecting
mine disposal sites to exploit natural treatment processes where possible.
The proximity of suitable refuse disposal sites should also be factored
into the site location process for preparation plants.
Figure 5. Coal preparation plant slimes being
dewatered in surface mine operations,
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Figure 6. Coal preparation plant refuse slimes
being built in surface mine.
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SECTION 2
SUMMARY AND CONCLUSIONS
Since the quality of water discharged from surface mining is regulated,
its control must become part of the planning process and is especially
critical in the preparation of permit applications. Water quality control
procedures should be coordinated with the development and application of the
mining system and with final reclamation procedures. The technological
approaches vary widely geographically, especially with the terrain and its
near-surface characteristics.
Various mine restoration and mine drainage pollution abatement measures
can be adopted to reduce or eliminate mine drainage originating within sur-
face mines located in the eastern coal region watersheds. These should be
selected with several factors considered. Mine drainage can be collected
and treated during active mining. For selected mines, treatment may be
required for a period in the future to eliminate pollutants that may persist
following mine restoration. The hydrogeological and geochemical setting
should be understood for the mining region where an abatement procedure is to
be adopted to assess the magnitude of the problem expected during and fol-
lowing mining. Such knowledge will greatly increase the probability that the
restoration program will have the intended benefits. Also, areas and methods
should be selected for treatment where the maximum benefits can be achieved
at the lowest cost. As pollution abatement measures become more complex,
they will increase in cost. However, the long-term environmental costs to
society may prove to be lower with the use of these initially more involved
and costly abatement measures, since mine drainage pollution may continue
long after mining and restoration are complete. Mine drainage runoff fol-
lowing mining may not be a point source of pollution, as was the case during
mining; but it may appear as a more difficult to handle, diffuse source
(i.e., scattered seepages and diffuse groundwater pollution).
STEPS IN PREMINING PLANNING
Planning for mine drainage control begins with accumulation of proper
data during exploration, usually from drilling data, sample collection
(strata and water), and aerial sensing. In addition to actual mining and
area reclamation, attention must be given to coal, overburden, preparation
plant, and transportation (especially haul roads); to the storage of mined
coal; to coal preparation refuse disposal; and to economic relationships.
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The phytogenic origin of coals over long periods of time has created a
heterogeneity that requires specific engineering for each mining site.
Accordingly, detailed coal and associated strata characteristics must be
established.
The water encountered in surface mining originates from precipitation
and is usually of the highest quality. The form and quantity of water
reaching the earth's surface is distributed between surface runoff and that
which moves underground near the surface. The ratio of the water distri-
bution becomes a critical parameter and demands appropriate consideration of
prevailing meteorological patterns. There is seldom significant change in
quality of surface waters beyond their ability to cause erosion and carry
sediment to the prevailing watershed drainage system. It is the control of
flow rates that becomes critical.
In contrast, those waters that reach the subsurface serve as a con-
tinuing lixiviant, dissolving various levels of contacted strata or enhancing
chemical reactions that result in the formation of water soluble substances.
Accordingly, it is necessary to establish underground flow patterns and rates
as well as the components of strata (not just coal seam components) that are
potentially water soluble. The parameters of concern are the quality of the
percolating waters, the solubility of individual minerals, and the rates of
solution. The concern relates not only to man's mining activities that
denude and disturb the near surface, but to the numerous natural phenomena
that prevail in these complex systems.
Those mineralogical components of greatest interest that control the
solution process include carbonates, sulfides (especially pyrite), and
silicates (as regards alumina and silica release). There are numerous minor
and trace substances (manganese, cadmium, zinc, etc.) that require special
consideration.
Pyrite (FeS2) is perhaps the most critical component. Despite its
relative insolubility, it is capable of being oxidized (with air, water, and
bacteria) to form highly water soluble sulfates that are especially dele-
terious to water quality. The parameters controlling pyrite oxidation
include grain-size distribution/concentration, pyrite-water-oxygen contact
potential, the crystalline nature of the pyrite, and various physical-
chemical parameters such as water quality, the oxidation potential Eh,
temperature, and flow rates. It has been shown that certain autotrophic
bacteria also play an important role in pyrite oxidation.
Government regulations (State and Federal) have been developed, culminating
in the Coal Mining Operating Regulations (1976), The Coal Mining Effluent
Guidelines (1977), and the Surface Mining Control and Reclamation Act (1977).
APPROACHES TO WATER QUALITY CONTROL
The approaches to water quality control in surface mining involve the
control of water movement, the nature of the overburden, the control of
10
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conditions with water pollution potential during active mining, the utili-
zation of settling ponds, the treatment of waters, when necessary, to meet
effluent standards, and the development of water storage areas as an
alternative to direct release.
Control of Water Movement
The control of water movement may involve surface flow control and/or
strata dewatering. The objective is to divert surface flows from the dis-
turbed areas and to control those surface waters that reach the surface
mine. Premining evaluation of these flows and of their quality is critical
and should include establishment of regions of higher water permeability.
Actual strata dewatering appears to offer a viable, low-cost alternative,
but it has not been adequately demonstrated to date. Surface waters should
be controlled and directed to settling basins for possible treatment and/or
sediment removal.
Nature of the Overburden
The characteristics of the overburden should be established to deter-
mine the potential for water quality degradation from soluble components.
Such data, usually obtained from core samples, result from chemical and
mineralogical analyses of the strata and from analyses of water leached
through the strata. Though standard tests for the latter analyses do not
exist, they provide some useful guidelines. The leaching tests do not
establish oxidation rate levels for pyrite. Overburden characterization
does establish the presence of topsoil (for replacement) and potentially
toxic strata that usually require segregation and selective replacement.
The relative amounts of these overburden classes will establish handling
and disposal procedures and some general mining costs.
Replacement of potentially toxic spoil requires the selection of lo-
cations that will either provide the least possible water contact (to
minimize sulfide oxidation and water mineralization) or the greatest neu-
tralization (because of the presence of alkaline soil and groundwater).
Control of Potentially Polluting Conditions
Mining procedures should minimize the amount of silt and coal fines
introduced into waters encountered in the open pit. These effects minimize
silt removal and water treatment requirements.
Utilization of Settling Ponds
Any waters that develop in the open cut should be pumped out promptly
and transported (by pipe or ditch) to the settling basins. Flocculant use
may be necessary to enhance silt and sludge settling rates. Flocculants
require detailed attention for most effective use.
11
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Water Treatment to Meet Effluent Standards
Water quality degradation may be minimized by the addition of alkaline
reagents (hydrated lime, limestone, or bag house lime) to water in the open
pit; otherwise, more complex treatment measures may be required. Oxidation
of soluble ferrous iron seldom is necessary during water treatment in
surface mining. Portability of equipment to control alkali additions in
water from surface mining sometimes favors use of more expensive reagents
such as soda ash or caustic soda. Reliable, controlled addition of solid
hydrated lime may be difficult to attain. Proper mixing of the solid
reagents must be accomplished, or their effects will be minimal.
Monitoring treated waters to ensure effluent quality should be incor-
porated into premining planning. Procedures and equipment are available.
Maintenance of all water quality control measures is important.
Water Storage
Often topography and/or postmining land use may suggest development of
lakes, ponds, or water storage areas. Such procedures have the potential
for enhancing land use levels and providing needed water supplies.
BASIC ELEMENTS OF WATER QUALITY CONTROL
The basic elements of water quality control for premining planning are
as follows:
1. Acquisition of necessary data regarding:
a. Surface water flows, elevations, vegetative covers, and
surface water quality.
b. Meteorological data (including a 10-year return frequency
and a 24-hour duration precipitation event).
c. Underground water flows, locations, levels, and quality.
d. Strata characterization from surface to several feet
below the lowest coal seam to be mined (especially
permeability and sulfide-carbonate presence).
2. Development of a plan to divert water from area to be disturbed
by mining.
3. Collection and handling of surface waters and groundwaters from
active mining area.
4. Collection of all area waters for sediment and quality control
before effluent release.
5. Design of mining plan from the exploration through reclamation
phases to control water quality most efficiently and economically.
The plan should take into account slopes and erosion.
12
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SECTION 3
OVERVIEW OF THE MINE
DRAINAGE CONTROL PROBLEM
RELATIONSHIP OF GEOGRAPHICAL TRENDS TO WATER QUALITY MANAGEMENT
Of the two principal coal-forming periods in North America, the one that
occurred in the central and western states was much later than that in the
eastern and southeastern states. The coals on opposite sides of the con-
tinent were thus derived from plants of very different types, since consid-
erable evolution occurred in the 150 million years between the Carboniferous
and the Cretaceous periods. Moreover, for any geological age, coals were
deposited in a number of distinct basins in different parts of the country
where they experienced distinctly different geological histories. For these
reasons, the coals from the several major deposits have different properties.
Of particular importance to water quality management are the various sulfur
contents of coals, as shown in Figure 7. This figure shows the known U.S.
bituminous reserves as of January 1965, classified by geological province
and sulfur content. The presentation shows clearly the predominance of low-
sulfur coals in Colorado, New Mexico, Texas, Utah, and Wyoming, and large
reserves of medium- or high-sulfur coals in the Illinois-Indiana region and
in Missouri, Kansas, and western Kentucky (Haley, 1974).
On a geographical basis, the bituminous coals of northern Appalachia
tend, in situ (as opposed to prepared coals), to average about three percent
total sulfur. By contrast, the southern Appalachian coals are decidedly
lower in sulfur content (approximately one percent). Further to the west,
the coals of the interior province increase in total sulfur content, fre-
quently exceeding five percent in Iowa (U.S. Bureau of Mines, 1976). With
many exceptions, these in situ total sulfur levels reflect the pyrite content
of the coal and associated strata (Lovell, 1975) as related to the geological
history of the coals (Williams, 1960; Caruccio, 1972). This is also evident
in prepared coals of the several regions (Deurbrouck, 1972), as illustrated
in Table 1 (Cavallero, et al., 1976).
The U.S. Bureau of Mines Information Circular 8301 (Walker and Hartner,
1966) gives information on the distribution of pyritic and organic forms of
sulfur in a large number of coals from most states of the Union. In low-
sulfur coals (<0.6 percent), most of the sulfur (>70 percent) is in the
organic form. In coals of higher sulfur content, the proportions of organic
and pyritic sulfur are roughly equal, although in some cases there is excess
pyritic sulfur.
13
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SULFUR CONTENT
< 1%
1.1-3.0%
>3.0%
0.0
Province I Province 2a Province 2b
( Pennsylvania , (Illinois,Indiana) (Missouri,Kansas,
Ohio.Tennessee, Western,Kentucky)
Alabama,Virginia,
West Virginia,
Eastern Kentucky)
Province 4
(Colorado,
New Mexico,
Texas,Utah,
Wyoming)
Figure 7. Distribution of U.S. bituminous coals by geological
province and sulfur content.
14
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TABLE 1. SUMMARY OF COMPOSITE 1.60 SPECIFIC GRAVITY PRODUCT ANALYSIS, BY REGION*
Cumulative analysis of float 1.60 product
Region
Northern
Appalachia
Southern
Appalachia
Alabama
Eastern Midwest
Btu
recovery
(%)
92.5
96.1
96.4
94.9
Ash
(%)
8.0
5.1
5.8
7.5
Pyritic
sulfur
(%)
0.85
0.19
0.49
1.03
Total
sulfur
(%)
1.86
0.91
1.16
2.74
so2f
(lb/
million
Btu)
2.7
1.3
1.7
4.2
Calorific
contentt
(Btu/lb)
13,766
14,197
14,264
13,138
S02 removal
erficiency
required*
(
-------
Potential water quality changes related to coal characteristics and
surface mining are closely correlated with pyrite content and alkaline-
mineral content of the coal and associated strata, which are quite different
throughout the study region. In eastern coals of the Pennsylvanian age, the
confining strata range from more than 50 percent limestone beds in Missouri
to less than five percent at the eastern edge, where interbedded sandstone
and shale members predominate (Koppe, 1975). More detailed discussion of
the occurrence of coal and carbonates is presented in Volume 3 of this
study, Geology of Eastern Coalfields.
ORIGIN AND QUALITY OF WATER ENCOUNTERED IN SURFACE MINING
All water reaching a mine site originates from precipitation as rain,
snow, or ice, either by gravity flow along the surface of the earth or via
percolation through the near-surface strata. The initial quality of this
water is characteristically excellent since it has passed through phase
changes. The impurities that are later acquired include airborne solids,
reacted water soluble gases, and possibly low vapor pressure liquids.
Several sources are available for precipitation water quality data, such
as the U.S. Geological Survey (Schneider, 1968) and the Geographical Sur-
vey for several states. The solubilization of contaminants in precipi-
tation commonly results in water quality changes, especially pH and
conductivity. The extent of these changes has large, regional geographical
implications reflecting land use (urban, forest, industrial, etc.).
Meteorological Factors
The quality of precipitation, its fluctuating levels, form, frequency,
and magnitude are the meteorological factors that influence water en-
countered in surface mining. These factors partially depend on terrain,
land use, and proximity to major water bodies. Basically, the quantity of
water to be considered in surface mining is a function of precipitation
levels (Hebley and Braley, 1955), whereas the rate at which the water
reaches the mine area is modified by elevations, surface cover, soils, and
the geologic and hydrologic systems involved. Generalized meteorological
data for the study region are available in the publications of the National
Weather Service, National Oceanic and Atmospheric Administration, U.S.
Department of Commerce. Three publications in particular are of interest:
the daily weather reports, the climatological reports, and the daily
synpotic weather maps.
These meteorological factors join the geological and phytogenic vari-
ables to establish the movement of precipitated waters into two major
categories: (1) surface runoff, and (2) percolating groundwater. The
water distribution between these categories has major impact on environmental
water control in mining. In each case, aspects of flow rate and mineral
contact, which are partially subject to man's manipulation, offer the basis
for water management.
16
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The Nature of Surface Runoff Waters
Various topographical, geological, hydrological, physical, chemical,
and biotic factors interact with precipitation levels to establish the
quantity and quality of water entering a mine area. The surface runoff
rate is subject to the limited natural control offered by \egetation, and in
man-disturbed areas it is partially directed by collection ditches to prevent
undesired erosion, sedimentation, distribution, and quality deterioration.
Vegetation of the surface offers the greatest control response to
runoff rates. It acts as a water storage mechanism to slow runoff rates
but permits continued flow over longer time frames. The clearing of a
portion of a forested region before surface mining interrupts a natural sur-
face water distribution format, and unless the changed flow is properly
controlled, it can result in severe, short-term area water loading and quality
degradation (Figure 8). These actions lead to erosion, stream siltation,
localized flooding, interference with the mining operations, and long-range
water quality problems. A heavy rain can lead to severe siltation within a
very few minutes from haulroads, overburden, and topsoil storage areas.
Preferably, siltation control basins should be established before clearing
operations begin. Detailed design considerations for erosion control can be
found in Erosion and Sediment (Hittman Associates, 1976).
The quality of water runoff from vegetated areas generally shows minimal
change, although a washing effect of surface dust coatings as well as vege-
tation liquids and gases can change water quality. These surface waters may
have increased levels of dissolved carbon dioxide, which can enhance the
solubility of any carbonate strata contacted and thus increase its alkalinity.
Figure 8. Continuous erosion from a reclaimed
surface coal mining operation.
17
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The quantity of water absorbed by vegetation (whether directly or in-
directly through the soil) is significant since it will be utilized in the
plant metabolism and transpired in part to the atmosphere, thus decreasing
the amount of water that would remain in the soil water and groundwater
systems.
Water reaching the surface of the earth, whether directly or indirectly
from vegetation, will flow or accumulate in response to its rate of release.
The rate of this flow is a function of the nature of the surface of the
earth, especially elevation variations. At greater flow rates, the energy
of flow will have the capability of moving surface particulate matter from
one place to another. Particle size, density, and compaction are the major
controlling factors in this movement. These surface flows vary greatly in
velocity. Levels of erosion usually increase with flow velocity. With a
twofold velocity increase, particles of 64-fold mass will be moved, and 32-
fold more material will be carried (Buckman and Brady, 1972). These values
are suggestions that relate to Stokes' Law and the Newton-Rittinger equation
as adapted to sluices and enclosed conduits. Stokes' Law and the Newton-
Rittinger equation enable the calculation of the terminal velocity of
settling particles. This velocity is a function of the particle size distri-
bution and fluid velocity and viscosity.
Basic surface water flow, which is from higher to lower elevations,
eventually forms a streamlet that reaches existing permanent streams. It
is the period of time between the first water contact with the surface of the
earth and its arrival at a stream that becomes critical in these studies.
Because surface mining disturbs the surface and removes vegetation, it will
tend to shorten this time frame, thus enhancing the movement of large
quantities of particulate matter and increasing solids dissolution by the
water flow. These two basic considerations are important in the control of
water pollution from surface runoff.
The Nature of Percolating Groundwater
Water that infiltrates the ground surface will continue to move to lower
levels at different rates, effectively forming an underground reservoir,
where it may flow laterally or vertically. In some geohydrological settings,
the attitude and sequence of strata may create an artesian aquifer. The
nature of the underground movement of water, including its depth, is pri-
marily a function of its geohydrological setting. This water may be
discharged as a free-flowing spring, or it may seep, be consumed by plants,
or be pumped from the earth by man. The distance of underground water move-
ment can be extensive (miles), but it is controlled by the surface elevation
and permeability of the geologic formations and related hydraulic boundary
conditions (see Volume IV of this series, Mine Hydrology). Accordingly, the
interactions are not limited to the mine site.
Rate of Infiltration—
Many parameters determine the rate at which water will infiltrate into
the strata: soil texture and structure, vegetal cover, biologic residual
structures, moisture content of the soil, physical condition of the surface,
water quality and temperature, etc. (Thornbury, 1969; Taylor and Ashcroft,
18
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1972). Infiltration capacity decreases exponentially in time from a maximum
to a slower constant rate approaching a saturated condition. The saturation
and infiltration rates may be modified by swelling of clay particles. Sur-
face runoff increases when precipitation intensity exceeds infiltration
capacity, unless there is a localized geological discontinuity.
Various surface discontinuities such as faults, zones of fracture con-
centrations underlying lineaments and fracture traces, and joints represent
localized regions of enhanced strata permeability and subsurface flow.
Changes in localized groundwater flow systems caused by surface mining pose
great difficulties in surface mine water control. The original near subsur-
face aquifer system is disturbed, and a new system will eventually be estab-
lished upon completion of the mine restoration. The replaced system is
characteristically more porous and homogeneous, despite compaction efforts.
It is the time frame of contact and the interactions of the groundwater
with the subsurface strata that constitute the major considerations of water
quality control in mining. This most critical factor concerns the effects
of water movement and subsequent changes in water quality that occur during
and after mining and that would not have otherwise occurred.
Natural Beneficiation—
Naturally occurring phenomena that change surface mine water quality are
termed "natural beneficiation." The effects of these phenomena can be uti-
lized as water quality control measures (Lachman and Lovell, 1970). Natural
beneficiation may involve the diversion of surface or groundwaters, or it may
achieve the mixing of alkaline and acidic waters from several sources. Such
mixing may result in dilution, dissolution of solids, or reactions between
water components to improve quality, form insoluble substances, or result in
physical absorption of certain water components on other surfaces.
Mineral Solubility—
The quality of groundwater is primarily controlled by (1) solubility of
minerals and transportation of insoluble substances contacted by the waters
on the surface, (2) the solution of minerals and organic matter contacted by
the soil water and groundwater, and (3) the quality of precipitation that may
enhance the solution of some carbonate materials. In addition to direct dis-
solution of minerals or their components, chemical reactions may occur among
the water, air, and biotic population that can alter mineral composition and
result in greater water solubilities. Potential also exists for ion exchange
activity among percolating waters, soil components, and various minerals,
which can cause changes in water quality. Thus the mineralogy of coal-
bearing and associated strata is important in determining potential water
pollution problems. Once a groundwater has achieved a characteristic compo-
sition from mineral solubilization, its capacity as a lixiviant may be
enhanced, increasing the potential for further reaction when mixed with any
other groundwater or contacting other strata.
Carbonates—The most water soluble mineral components commonly encoun-
tered in coal measures are the carbonates, which add calcium, magnesium,
carbonate, and bicarbonate ions to the waters, generally raising the pH, the
19
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alkalinity, and the buffering capacity. Some vegetation may introduce carbon
dioxide and/or natural organic acids into the water, which may lower its pH
but at the same time increase its ability to dissolve carbonates.
Commonly, water that contacts coal strata or coal products (such as in a
preparation plant) will dissolve small concentrations of mineral and coal
components (humic acids, for example). But this process has negligible ef-
fects on water quality other than increasing its total dissolved solids and
conductivity (Lovell and Reese, 1965). However, these dissolved solids may
increase the lixiviant characteristics of the percolating waters to dissolve
carbonates, clays, etc. Alkaline water may decrease the undesirable pollut-
ant loading by reducing the tendency for pyrite oxidation directly (Barnes
and Romberger, 1968) or by inhibiting bacterial activity (Lorenz and Tarpley,
1963).
Pyrite — The most obvious source of coal mine drainage pollution is the
mineral pyrite, which occurs in varying amounts in all coal measures. An-
other iron sulfide mineral, marcasite, is usually considered a less signifi-
cant source because of its less frequent occurrence in coal-bearing strata.
Pyrrhotite and troilite (FeS) are rare in coal measures.
Various other iron or sulfate minerals such as melanterite,
coquimbite, Fe2(S04)3»9H20; halotrichite, FeAl2 (804)4 «22H20; capiopite, (Fe, Mg)
Fe^(SO^)6(OH)2*20H20; alunogenite, A12(SO^)3' 18H20; gypsum, CaSC^^I^O; and
siderite, FeC03 are generally believed to be of secondary origin and are
usually present at insignificant levels in coal measures.
Coals also contain sulfur in the organic form, originating with the
parent vegetal coal source. These substances do not contribute to coal mine
drainage formation or water pollution.
There does seem to be a direct relationship between the pyritic sulfur
level of coal and existing water pollution levels, but there are many extra-
neous factors that create deviations. Before significant pollution levels
are attained, the pyrite must be oxidized to water soluble substances. Thus
the rate of this oxidation becomes critical.
Frequently, the existence of pyrite concentrations in strata above or
below a coal seam is ignored as a pollution source, though they may be the
major offending source. Pyrite may also be found in limestone, sandstone,
and shale associated with coal seams (Hanna and Brant, 1971; Newhouse, 1927),
where it commonly occurs in distinct bands or lenses at very high concen-
trations .
Factors Affecting Pyrite Oxidation and Solubilization. Among those
factors affecting the ease of pyrite oxidation and solubilization are size
(Caruccio, 1970), distribution and concentration of pyrite grains, ease
of contact between pyrite grains and water, pyrite/water contact time,
surface area of pyrite particles, crystallinity of pyrite, and purity of
pyrite grains (Caruccio, 1972).
20
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Water quality factors impinging on pyrite oxidation and solubilization
include pH, Eh, ionic strength, and concentrations of dissolved oxygen,
acidity, alkalinity, carbonate, bicarbonate (Caruccio, 1968), total dissolved
solids, ferrous iron, and ferric iron. Physical factors include temperature,
water flow rates, extent of agitation, aeration, pressure, presence of sedi-
ment, minor soluble components (Hem, 1960), densitj' variations, and depth of
flows and channels. There are also pronounced effects from autotrophic bacteria.
In natural waters with pH levels above 4.8, soluble ferric species
seldom exceed 0.01 mg/£ unless complex ions are present. Colloidal ferric
hydroxide is common to surface waters, even when they appear quite clear.
Reactions Resulting in Pyrite Solubilization. The chemical reactions
commonly cited to describe the formation of coal mine drainage are:
a. FeS2 + 3 02 >-
b. 2 FeSO. + 1/2 00 + H0SO. >-
4 224 ^tj^
c. FeS2 + Fe2(S04)3 + 8 H20 >• 3 FeS04 + 2 H2S04 + 12 H
d. 2 SO,, + 0_ *• 2 S0»
e.
f .
g. Fe2(S04)3 + 3 H20 - >• Fe^ + 3
The initial step involves the oxidation of pyrite to several water
soluble components, and thus the limiting factors are those variables that
control this oxidation reaction. Obviously, the water solubility of these
reactant and product substances is critical to the problem. Solubility
levels are detailed as follows:
_5
FeS? ....... 4.9 x 10 g/fc (Handbook of Chemistry and
Physics, 1952)
FeS04 ....... 2.08 x 1Q2 g/4 (20°C) (Linke, 1965)
FeO(Fe(OH) ) • • • 1.5 x 10~5 moles/£ (25 °C) (Linke, 1965)
[equivalent to 2.43 x 10 g/&]
Fe 0 (Fe(OH) ) • • 3.4 x 10~10 moles/£ (20°C) (Linke, 1965)
[equivalent to 9.08 x 10~8 g/£]
FeC03 72 g/£ (18°C - 1 atmosphere C02) (Linke, 1965)
Fe(SO,)_ Occurs in several phases (Linke, 1965):
Fe203 • 2.5 S03 • 7 H20
Fe203 ' 3 S03 -9 H20
Fe.O, - 4 S03 -9 H20
Fe203 • 3 S03 «8 H20
(Solubility ranges from 0.3 to 205 g/£ for Fe2(
and from 35.5 to 568 g/A for S03.)
21
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These and related reactions proceed at widely varying rates and in
varying orders, developing for each location some type of equilibrium as es-
tablished by the prevailing physical, chemical, and meteorological conditions.
However, the typically unsteady state conditions above and below ground
create a most complex system. It has been suggested that pyrite serves as a
catalyst for the oxidation of sulfur dioxide and the sulfite ion (Reaction d).
Reaction g results in a deposition of hydrous iron oxide but allows
sulfate species to remain in solution. The hydrous iron oxides coating
stream bottoms and streaking coal and other strata are indicators that coal
mine drainage was formed (Figure 9). Detailed study of these precipitated
deposits (Whitemore, 1973), often termed "yellowboy," has been made. Field
stability diagrams (Hem, 1970) show the stable equilibrium forms of iron
(Figure 10) and manganese (Figure 11) at various combinations of Eh and pH
in the environment.
Crystallization pressures of secondary minerals are thought to perpetu-
ate acid production by mechanical destruction of the pyrite-containing strata.
Although effective pressures encountered in practice generally range between 0.1
and 0.01 times theoretical crystallization pressures, these are often sufficient
to disrupt rocks containing reactive pyrite (Koppe, 1975; Winkler and Singer,
1972).
Figure 9. Aquifer drainage from highwall of Pennsylvania surface coal mine.
22
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WATER OXIDIZED
Fe(OH)?
WATER REDUCED
8 10 12 14
-0.80-
0
Figure 10. Fields of stability for solid
and dissolved forms of iron
(Hem, 1970).
-------
I 1 1 1
WATER OXIDIZED
tfATER REDUCED
-0.80
12 14
PH
Figure 11. Fields of stability for solid and
dissolved forms of manganese (Hem, 1970).
24
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Oxygen can reach the pyrite surface either in the gaseous phase or
dissolved in percolating groundwater. Even in dry mines and strata, pyrite
oxidation can occur, since any air circulation will carry water in the
gaseous state as humidity.
The item of concern after formation of water soluble products from
pyrites is their rate of entry into the effluent streams after contacting
the mineral surfaces. This rate depends on (1) flushing by a rising water
table, (2) water percolation through open channels and pores, and (3) the
diffusion of saturated solutions as a result of lowered vapor pressure.
Smith and Shumate (1970) have suggested that the development of some
ferric ion in chemical mine drainage (CMD) favors higher rates of pyrite
oxidation by Reaction c.
Contact of alkaline groundwaters with surface-oxidized pyrite may form
ferrous bicarbonate and basic ferric sulfates. Although such waters may
tend to minimize further pyrite oxidation, they frequently achieve a net
acidity before discharge from the mine.
Pyrite Oxidation. Since the oxygen diffusion rate (Smith and Shumate,
1970) in water is much slower than in air (x 10"^), it is assumed that vapor
state transportation of oxygen generally prevails. Upon contact of oxygen
at the pyrite surface, a reaction site is formed. The oxygen concentration
gradient in a particular stratum depends on (1) strata porosity (void volume
and its continuity), (2) exposed pyrite surface area/unit volume of strata,
and (3) order of pyrite oxidation reaction. The oxygen diffusion mechanism
will define the location of the pyrite reactive sites as they are exposed to
vapor and not submerged under more than 0.25 in. of water.
The rate of pyrite chemical oxidation may be limited either by the
reaction rate itself or by the reactant (oxygen) transport rate. In environ-
ments of less than two percent 02, the rate is first order and predominantly
chemical (Smith and Shumate, 1970). The depth of reaction (pyrite oxidation)
into the strata depends on oxygen diffusion (and thus really depends on
strata porosity).
Silica—Silica is found in most groundwater up to about 30 mg/£ (and
occasionally to 100 mg/£), varying with rock type and temperature. Various
clay minerals, residual quartz, or feldspars are common sources of silica.
Generally, solubility of silica is very low; but above pH 9.0, it may in-
crease rapidly (Davis and DeWiest, 1966). Undesirable interactions may occur
between dissolved silica and aluminum species.
Aluminum—Among the mineral solution strata reactions, conditions may
occur that favor extensive solubility of aluminum, presumably from clays or
shales. Aluminum is probably the most important of the metallic cations
found in coal mine drainage other than iron, as it creates acidic responses
in solution similar to iron ion species, and it can also create difficulties
during coal mine drainage treatment. Aluminum has seldom been described as
an obnoxious component of coal mine drainage, although it can be quite toxic
to some plants. The availability of aluminum in groundwaters is related to
25
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cation exchange capacity of the soils and strata as well as pH, ionic
strength, and the occurrence of soluble ions in the water (Brady, 1974;
Tisdale and Nelson, 1975). Aluminum is an unusual contaminant of groundwater
unless the pH is low (4.0), when it may occur as Al (OH,)~. When dissolved
silica occurs in groundwater, the polymerization of aluminum hydroxide pro-
ceeds in a unique fashion. For waters whose pH is below 4, aluminum solu-
bility has been estimated from the solubility product for gibbsite (Al(OH).,),
which is soluble in sulfuric acid. Gibbsite, though not common to coal
measures, is a likely alteration product of kaolinite (a common coal measure
clay mineral) by silica solubility.
Manganese—Manganese found in coal mine drainage may originate either
from isomorphic substitution in iron sulfides or trace levels of manganese
minerals in the coal strata as pyrolusite (MnO£), psilomelane (MnO-Mn02'2H20),
rhodochrosite (MnCC>3), or even manganite (M^C^-I^O). It is not unexpected
for some form of manganese to occur in coal measures, since this element
is essential in plant metabolism as a minor nutrient. The oxidation of Mn
and subsequent precipitation of Mn02 increases with pH and surface area.
Bacteria are also known to influence the rates of manganese oxidation.
i 2
Manganese is normally present in coal drainage waters as the Mn ion,
whose solubility increases as the pH falls below 7.0. The ion pair MnS04 has
been reported in waters containing high sulfate concentrations and may exist
in coal mine drainage. Manganese is difficult to remove from waters to
levels below the 1 mg/£ unless a high pH is maintained. The Eh/pH diagram
of Mn (Figure 11) illustrates these aspects (Hem, 1970).
Trace metals—Other elements in very low concentrations, such as ,
chromium, zinc, and cadmium, are not uncommon in coal mine drainage and are
considered acutely toxic. Studies of such occurrences have been increasing
in frequency (Rao and Gluskoter, 1973; Ruch, et al., 1973). No extensive
studies have been made regarding their removal by treatment processes, but
there has been regulatory consideration for the establishment of effluent
standards.
Mineral solubilization by autotrophic soil bacteria—There is little
doubt that autotrophic bacteria, specifically Thiobacillus ferrooxidans
and similar genera (Buchanan and Gibbons, 1974), play a major role in both
the oxidation of pyrite and of solubilized ferrous sulfate (Reactions a and
b) (Lorenz and Tarpley, 1963). These organisms utilize iron and sulfur in
their metabolism, and since they are aerobic, they draw their oxygen from
the air as well as use airborne carbon dioxide as a carbon source. They
grow optimally at pH levels near 3.0, whereas other species may metabolize
at higher pH values. They are relatively common soil bacteria, and they
frequently reach population densities exceeding 10 cells/ml.
26
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LEGAL ASPECTS OF MINE DRAINAGE CONTROL
Government Regulations
The legal status and government regulation (Federal and State) of water
pollution in general and that associated with coal mining ranges from the
Sanderson case in 1886 (Wright and Bauman, 1943) to the recently promulgated
(April, 1977) EPA guidelines (Coal Mining Guidelines and Standards, 1977)
and the Bureau of Land Management Coal Mining Operating Regulations (1976).
The effluent limitations under the Clean Water Act of 1977 (P.L. 95-217), Title
40, Part 434 (Coal Mining Point Sources) for best practical control technology
currently available are shown in Table 2. Effluent guidelines are also man-
dated under the Surface Mining Control and Reclamation Act of 1977 (P.L. 95-87).
Exceptions provide for the 10-year, 24-hr precipitation event and for
drainage from surface mines that have been returned to final contour, pro-
viding such drainage has not been comingled with untreated mine drainage
that is subject to limitations.
These effluent guidelines also include the proposals for best available
technology economically achievable, subject to future promulgation.
The national pollutant discharge elimination system (NPDES) (Schaffer,
1975) established a pollution elimination goal from point sources for
navigable waters by July 1983, which charges the EPA with protection and
maintenance of water quality. This goal is to be achieved by a national
TABLE 2. EFFLUENT LIMITATIONS UNDER TITLE 40, PART 434, OF THE
CLEAN WATER ACT OF 1977 (COAL MINING POINT SOURCES)
„ . -, Daily average
Item Daily maximum on j
over 30 days
Subpart C, Section 434.30 -
434.32 (Acid or Ferruginous
Mine Drainage):
Iron, total (mg/£) 7.0 3.5
Manganese, total (mg/£) 4.0 2.0
TSS (mg/JO 70.0 35.0
pH 6.0-9.0
Subpart D, Section 434.40 -
434.42 (Alkaline Mine Drainage):
Iron, total (mg/£) 7.0 3.5
TSS (mg/£) 70.0 35.0
pH 6.0 - 9.0
27
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permit system (NFS) and stream quality standards (P.L. 87-88, 1961), in
conjunction with State regulations (Commonwealth of Pennsylvania, 1937).
Available guidelines for the coal industry (Coal Mining Effluent Guidelines
and Standards, 1977) cover only best practical control technology currently
available. Yet to be released by EPA are guidelines for best available
technology economically achievable and toxic pollutants, new source per-
formance standards, pretreatment standards, and the identification of control
measures and practices to eliminate the discharge of pollutants. The per-
mits, granted for periods up to five years, cover deep and surface coal mines
and preparation plants. They may incorporate special provisions, self-
monitoring requirements (in conjunction with State requirements) for pH,
concentrations of iron, acidity, and suspended solids, and effluent limi-
tations (daily average and maximum)—all based on the industry guidelines,
including modes of sampling and analysis. Permit time limits are usually
associated with release of State reclamation bonds. Any State may impose
additional or stricter regulations, which then become a Federal requirement
of the permit.
According to the Permanent Regulatory program of the Surface Coal Mining
and Reclamation Operations under the Surface Mining Control and Reclamation
Act of 1977 (P.L. 95-87, Title 30, Chapter VII, Subchapter K, Section 816.42X
all drainage from the area disturbed by surface mining, including disturbed
areas that have been graded, seeded or planted, shall be passed through a
sedimentation pond or a series of sediment ponds before leaving the permit
area. Sedimentation ponds and other treatment facilities shall be maintained
until the disturbed area has been restored and the revegetation requirements
are met and the quality of the untreated drainage from the disturbed area
meets the applicable State and Federal water quality standards requirements
for the receiving streams.
A bypass provision may be developed for a major precipitation event (to
6 hr after the event), and thus regulations are excluded during that period.
The discharger must be able to prove that such an event occurred if
questioned.
Other Legal Considerations
Conflicts over water rights are usually resolved in common law courts
using the property system and the doctrine of nuisance. A water right is a
property right and is entitled to the same extent of protection as other
forms of property. A water right is a usufructuary right to the flow and
use of water. The water is generally considered to remain common property
until it has actually been diverted from its natural course and reduced to
private possession by means of artificial devices (Thomas, 1955).
The law of water^rights embraces two diametrically opposed doctrines
and numerous modifications and combinations of those doctrines (Thomas,
1955). In many states, water rights are based on ownership of land con-
tiguous to a stream or other source, or overlying a groundwater reservoir
(land ownership rights); the right does not depend on putting the water to
use, and thus it is not lost by nonuse. However, in some States, water
rights are based entirely on appropriations and actual use of water that has
28
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been declared to belong to the public (approprlative rights). Such rights
are based on priority in time, and they may be forfeited if the water is
allowed to go unused for a specified period. But ownership of land is not
essential. In the remaining states, both these doctrines or modifications
thereof are accepted, and each applies to certain classes of water or to
certain conditions of development. Figure 12 shows areas of the United
States with moisture surplus and deficiency and indicates the basis of water
rights in various states (Thomas, 1955). As the map indicates, the Appala-
chian and eastern interior coal basins fall strictly under the riparian
doctrine or land ownership basis of water rights, whereas the western in-
terior basin employs a combination of appropriative and land ownership rights.
A summary of water rights and their legal consequences for the States that
make up the Appalachian^region and the eastern and western interior regions
is provided in Tables 3 through 5 (National Water Commission, 1973).
Riparian Rights—
Under the concept of riparian rights, the owner of land adjacent to a
stream (riparian land) is entitled to receive the full natural flow of the
water without change in quality or quantity. No upstream owner may materi-
ally decrease or increase the natural flow of a stream to the disadvantage of
a downstream owner. A number of modifications have been made to this doc-
trine over the years to permit reasonable use of waters. The major modifica-
tions as presented by Linsley et al. (1968) are listed as follows:
1. Reasonable Use - A man's right to use water on his own land must be
restricted to a reasonable use in view of the similar rights of
others. Reasonableness of use is usually determined by such
factors as area, character of the land, importance of the use, and
possible injury to other riparian uses.
2. Correlative Rights - Wherever landowners have rights in a common
water supply that is insufficient for all, each is to receive a fair
and just proportion.
Other important aspects of riparian rights include:
1. An upstream proprietor may always use as much water as he needs for
domestic use and for watering domestic stock. Such use is con-
sidered an ordinary or natural use.
2. Irrigation water used for mining facilities or watering of
commercial herds of stock is an artificial use.
3. Riparian rights can be lost by upstream adverse use that ripens
into a prescriptive right at the end of the period specified under
the statute of limitations.
4. If a parcel of riparian land is divided, any section not adjacent
to the stream loses its riparian status unless the right is
specifically preserved in the conveyance.
5. Riparian rights do not attach to land outside of the stream basin,
even though such land is contiguous to riparian land in the basin.
Appropriative Rights—
The basic concept of the doctrine of appropriation, or Colorado doctrine,
is that the landowner has no inherent right to use water from sources upon,
29
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APPROPRIATE
AND
LAND
OWNERSHIP
RIGHTS | L.
RIGHTS
Areas of deficiency
Figure 12. Areas of moisture surplus and deficiency in the United States and the basis of water rights
in various States (Thomas, 1955).
-------
TABLE 3. SUMMARY OF WATER RIGHTS FOR THE APPALACHIAN REGION*
State
Extent of existing law
t
Comments
Ohio
Pennsylvania
Limited to water quality
control, water use plan-
ning, the regulation of
dam construction, and
drilling of water wells.
Permit system to control
water use by public water
and power supply agencies
and has a number of stat-
utes designed to protect
navigation, to improve
water quality and to con-
serve and use water in
accordance with balanced
water planning.
State has no statutory procedure governing the acquisition,
distribution, or transfer of water rights. Conflicts are re-
solved by the courts in private litigation on a case-by-case
basis and judged by the principle of reasonable use. Primar-
ily rights of usage are for domestic purposes and municipal-
ities in Ohio situated on a natural stream, and considered
riparian proprietors may supply water to all of its inhabitants.
The Water Pollution Control Board is responsible for issuing
discharge permits.
Little State administrative control in the areas of water
rights. Riparian water rights and uses are not administered but
are subject to certain regulations, such as water quality
standards and navigational controls. Conflicts are settled
in the courts, and relief is rewarded in the way of an injunc-
tion to prevent interference with the land owner's water
right or money damages for unlawful injury or impairment to
water rights or uses.
In 1971, the Department of Environmental Resources was formed,
and it has responsibility for water resources, outdoor recre-
ation, and water pollution. It also implements the PA Clean
Stream Act based on a permit system, can call for payment by
a water user "in lieu of"cleaning the user's discharge if the
State feels the funds would serve the public welfare more.
(Continued)
* Source: Adapted and modified from National Water Commission, 1973.
t All water rights doctrines used are riparian.
-------
TABLE 3. (Continued)
State
Extent of existing law
Comments
Maryland
West Virginia
Based on a permit system
which (1) permits for the
rights to appropriate or
use both surface & ground-
water and (2) permits for
construction of reser-
voirs, dams and waterway
obstructions.
Very limited; there has
not been extended treat-
ment by either courts or
legislation.
Virginia
Regulation is largely
confined to navigation,
fisheries, shellfish,
and flood control.
State operates under 1934 legislation setting up permit system.
The Department of Water Resources controls State permit system.
1970 law repealed old water pollution laws and expressly pre-
served the right of riparian owners to suppress nuisances or
to abate pollution in equity or under common or statutory
law. The Act also made it unlawful to pollute State waters.
Violators may have a hearing or have to submit a report, and
they can be sued.
Most problems in the past have centered around the disposition
of excess water rather than conflicts over use of existing
supply. Where conflicts have arisen, the courts have adopted
the reasonable use doctrine of riparian water rights. Al-
though there is very little State administrative control over
water rights, there is a Division of Water Resources that
takes inventories of resources, formulates comprehensive
plans and makes recommendations for protection.
West Virginia Water Pollution Control Act states that it is
public policy to maintain reasonable standards of purity & quality.
Problems have been increasing because of the competition of
water in the coastal plain. A need for some kind of regula-
tory or permit system has been identified. Disputes are
settled in the courts on a case-by-case basis (under
reasonable use doctrine).
1970 Water Control law regulates water quality through State
Water Control Board.
(Continued)
-------
TABLE 3. (Continued)
State
Extent of existing law
Comments
Kentucky
Tennessee
u>
UJ
Alabama
In 1966, the legislature
passed! legislation that
provides for a limited
amount of State adminis-
trative control over the
utilization and alloca-
tion of the waters of
the State. All other
rights are riparian and
subject to reasonable use.
General lack of legis-
lation on water rights.
Legislation has been
confined to drainage
and pollution problems.
Conflicts are solved in the courts on a case-by-case basis.
There is a State Water Pollution Control Commission which
oversees and issues permits to discharge wastes of other
matter into State water. It also has emergency powers to
protect the public health.
Tennessee courts apply reasonable use doctrine of riparian
rights and the reasonable use principle. There is virtually
no State administration of water rights. There is a Water
Quality Control Board that regulates water quality and pol-
lution by the issuance of permits.
Water use conflicts are regulated in private litigations
by reasonable use doctrine. There are no State administra-
tive units to regulate use, but State Water Improvement
Commission controls water quality and pollution; flood
plains are also regulated.
-------
TABLE 4. SUMMARY OF WATER RIGHTS FOR THE EASTERN INTERIOR REGION*
State
Extent of existing law
Comments
Illinois
Indiana
u>
Kentucky
There are some statutes in
Illinois regulating the man-
ner in which water may be
used. However, there is no
comprehensive legislative
effort to provide State ad-
ministrative control over
water use or rights.
Law has developed slowly and
is not extensive.
In 1966, the legislature
passed legislation that pro-
vides for limited State
control over the use and
allocation of waters. All
other rights are riparian
and subject to reasonable
use
Water rights are incidental to ownership of land abutting a
stream apart from statutory regulations and control over
water quality by a couple of State agencies. The rights of
the riparian land owner extend to quality as well as quantity;
conflicts are decided on the principle of reasonable use.
Indiana law is not fully defined but seems to be based on the
reasonable use doctrine of riparian rights. In recent years,
the legislature has enacted legislation for the control of
water pollution and has adopted limited administrative con-
trols relating to the right to use surface and groundwater.
The Dept. of Conservation controls groundwater withdrawals
and the Flood Control and Water Resources Commission regu-
lates surface water. In 1955 the legislature declared surface
water to be public waters and controlled by the State.
Conflicts are solved on a case-by-case basis. There is a
State Water Pollution Control Commission that issues permits
to discharge wastes into State waters and exercises emergency
powers to protect public health.
* Source: Adapted and modified from National Water Commission, 1973.
t All water rights doctrines used are riparian.
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TABLE 5. SUMMARY OF WATER RIGHTS IN THE WESTERN INTERIOR REGION*
State
Water rights
doctrine used
Ripar-
ian
Appro-
priation
Extent of existing law
Comments
Missouri
Kansas
u>
Ln
There is little deci-
sional law relating to
groundwater. However,
the same rules that
govern underground
streams also govern
surface water.
Unallocated water is
subject to appropria-
tion, but all prior
rights - whether ap-
propriation or ripar-
ian - are preserved
and protected. Gen-
eral administration
of water rights is
under State control
and legislation.
There is no statutory regulation governing the ac-
quisition, administration, or distribution of water.
Conflicts over water rights constitute a judicial
decision area based on the riparian doctrine. In
1961, the State stepped toward water resource plan-
ning by creating a Water Resources Board. This is a
comprehensive planning board. Pollution is regu-
lated by the Water Pollution Board, which carries
out enforcement procedures against violators.
General administration of water resources is with
Division of Water Resources. A right can be
initiated only by filing application with the chief
engineer. In conflicts, domestic uses are privi-
leged. A Water Quality Control Act is administered
by the State Board of Health. The Water Resource
Board provides for comprehensive water resource
planning.
(continued)
*Source: Adapted and modified from National Water Commission, 1973.
-------
TABLE 5. (Continued)
State
Water rights
doctrine used
Ripar-
ian
Appro-
priation
Extent of existing law
Comments
Oklahoma
X
X State is basically ap-
propriative, but ripar-
ian rights still exist.
Statutes provide for
administrative control
and regulation of
State waters.
u>
Arkansas
Law is not extensive
except for law on
diffused surface
water and water on
watercourse.
Oklahoma Water Resources Board developed State Water
plans to insure best resource planning. State is
divided into water districts. To initiate a water
right, one must file an application with this board.
Anyone having a right to use, but impaired from that
use, may file suit in district court.
Water quality is regulated by Water Pollution Con-
trol Act administered by the Water Rights Board.
Appropriation rights may be obtained through the
Water Rights Board, pursuant to the relevant statu-
tory procedures, and riparian rights for domestic
use may be acquired by acquiring riparian land.
Riparian doctrine is followed except for the alloca-
tion and distribution of surplus water.
Conflicts are resolved in the courts, but more
State regulation could come about in the future.
Water quality is regulated by the State Soil and
Water Conservation Commission
-------
contiguous to, or underlying his land, but that rights to these sources are
based on priority in time of beneficial use and may be lost after the use
ceases (Thomas, 1955). In common usage, an appropriator is one who takes
exclusive possession of an article that has been recognized as common property
or that has been owned by others. Depending on the reactions of the true
owner, the courts may consider this act to be unlawful and criminal, or they
may legitimize it by reason of either long-continued adverse use or the
owner's consent.
The appropriation doctrine provides for acquiring rights to the use of
water by diverting it to beneficial use in accord with procedures that are
set forth in State statutes or acknowledged by the courts. Appropriated
water may be used on lands away from the stream as well as on lands adjoining
the stream. The earliest appropriator in point of time has the exclusive
right to the use of water to the extent of his appropriation without reduction
of quantity or deterioration of quality whenever the water is naturally
available. Each subsequent appropriator has like priority over all appro-
priation later in time than his own. Appropriations are for a definite
quantity of water and are valid as long as the right is exercised. Appropri-
ations may be made only for beneficial and reasonable uses.
Drainage Law—
The laws applicable to the disposal of storm runoff waters are also of
concern to mining operations. These laws apply to modification of natural
surface drainage patterns, and to date they have been applied principally to
urbanizing areas. However, inasmuch as surface mining operations can sub-
stantially alter the existing surface drainage patterns and consequently the
total volume of storm runoff for a given watershed, drainage law becomes a
concern of the mining engineer.
Two basic legal approaches have found widespread use in the United
States, namely, the Roman civil law and the common-enemy rule (Linsley et al.,
1968). The following list indicates the rule that is followed in various
states:
Roman civil law: Common-enemy rule;
Alabama Arkansas
Georgia Indiana
Illinois Kansas
Iowa Missouri
Kentucky Nebraska
Maryland Oklahoma
Michigan South Carolina
North Carolina Tennessee
Ohio Virginia
Pennsylvania West Virginia
Roman civil law specifies that the owner of high land (dominant owner)
may discharge his drainage water onto lower land through natural depressions
and channels without obstruction by the lower or servient owner. The dominant
owner can improve and speed up the flow of surface water by constructing
drainage conveyances such as ditches or by making improvements to existing
37
-------
channels. However, he may not carry water across a drainage divide and dis-
charge it on land that would not have received the water naturally, nor may
he locate the outlet of his drainage system at a point other than the natural
outlet of the area. On the other hand, the servient owner can do nothing to
prevent drainage from entering his property from above.
The basic principle underlying the common-enemy rule is that water is a
common enemy of all, and any landowner may protect himself from water flowing
onto his land from a higher elevation. According to this approach, a dominant
landowner may not construct drainage works that result in damage to the
property of a servient owner. Thus a drainage easement must be secured from
the servient owner to discharge surface runoff through his property. The
servient owner is allowed to construct dikes or other works to prevent the
flow of surface water onto his property.
Both of these legal approaches to drainage practice place the responsi-
bility for damages on any person or organization altering the natural stream
pattern of an area or creating an obstacle that blocks the flow of a natural
stream.
38
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SECTION 4
COMMON APPROACHES TO MINE DRAINAGE ABATEMENT AND WATER QUALITY CONTROL
CONTROL OF WATER MOVEMENT
In surface mining, the prevention and control of water quality degra-
dation and any necessary treatment of mine drainage require premining
planning, diversionary actions during site and mine preparation, constant
monitoring and action during mining, and water movement control during
backfilling and surface reclamation operations. The control of water move-
ment may involve any one or a combination of three basic water management
approaches, which include: (1) surface flow control, (2) soil water control,
and (3) strata dewatering. The objective of these management tools is
simply to divert the flow of waters from the mine area and thus, through
isolation, to reduce the opportunity for water quality deterioration. Pre-
mining evaluation of these water flows and qualities is critical, including
establishment of regions of higher water permeability.
The water management approaches discussed in this section are presented
because they appear to be applicable under many hydrogeological and geo-
chemical circumstances. But because not all have been adopted by the industry,
published documentation of costs and benefits are not always available.
Actual strata dewatering and, particularly, the control of potable and
polluted mine waters using largely mechanical schemes (i.e., connector wells
and disposal wells) have not been adequately demonstrated in the mining
applications to date.
Control of Water Movement as Related to Water Quality
The source of waters and their flow contacting coal-related strata have
been discussed in Volume 4, Mine Hydrology. The initial concern is to
establish before mining (1) the potential amounts arid sources of waters
(precipitation, surface runoff, and interception of aquifers), (2) flow
direction, and (3) characteristics (such as quality) that may be encountered
during mining. These variables must be correlated with localized conditions
to suggest potential factors indicative of water quality degradation. Pre-
vious mining history of the immediate area should be established to indicate
potential interception of abandoned deep mines and/or auger mining channels
or other natural conditions that could affect water quality. Detailed
drilling may be necessary.
The first consideration is the control of surface water flow by diver-
sion ditches around and within the disturbed site. Special diversion is
often helpful above and around the designed highwall. Surface streams may
39
-------
be encountered (sometimes only with seasonal flow) for which it may be
necessary actually to divert a stream channel. Such streams must be eval-
uated for regions of high bottom infiltration potential because they may be
a source for recharging underground aquifers and may thus have the potential
for introducing large volumes of water into the active pit during mining.
These zones of high permeability may be related to major concentrations of
fractures, joints, faults, or outcrops. The use of stereo aerial photographs
and detailed local geological data and maps are invaluable in establishing
these conditions. In controlling such regions of high streambed infiltra-
tion, stream channel liners, wooden sluice boxes, and canals may be used.
Regardless of the technique, the objective is to bridge the streamflow over
or around the permeable zone to minimize groundwater recharge and flow from
the stream.
Surface Flow Control
Various schemes have been adopted over the years to reduce surface
water inflow to active mines and thereby improve working conditions and
reduce pumping and treatment requirements. The initial objective is to
divert as much surface water as possible from the disturbed area by means
of diversion ditches and water flow channels that utilize the existing nat-
ural topography. On occasion, streams may have to be temporarily diverted
with new channels or pipes.
The active area of disturbance should be kept minimal, and the period
of time before reclamation and revegetation should be kept as short as pos-
sible. Working time should be coordinated with the local growing season as
much as possible.
Highwall diversion ditches are used throughout the mining region to
intercept sheet runoff and runoff in gullies and small streams. These
structures are often left intact following mine restoration, hence they
continue to divert excessive runoff from backfilled areas. Not uncommonly,
however, diversion ditches may become silted with time, breached by erosion,
or filled with ice packs in winter, thereby reducing their effectiveness.
Rarely are provisions made to maintain these structures following back-
filling. In addition, such ditches may be undersized and hence unable to
handle longer-term siltation and erosion problems. On the other hand, ditch
design to protect against the six-hour, 100-year flood may be excessive
and may in fact cause more problems than it was intended to solve. Large
diversion ditches can cause serious erosion situations and flooding problems.
Recently, more emphasis is being placed on erosion and sediment control
in surface mining, and more conservative design and construction practices
are being called for to minimize erosion and siltation during and- following
mining (see for example, Hittman Associates, 1976). Stone-riprap-lined
diversion ditches and protected channels constructed across backfilled areas
are now in use in some mining districts, as are concrete structures used to
check flow velocities and half-round concrete, metal, and bituminous fiber
pipes (Figures 13 and 14). Many innovations are possible for reducing sheet
erosion and hence sedimentation derived from strip mines. However, conflicts
will arise that must be considered in premining planning. Backfill slopes
40
-------
Figure
13.
Clearfield County, PA)
Figure
14.
41
-------
may be designed to reduce runoff, and hence erosion and siltation (Figure 15).
Any restoration design and structure that provides detention storage to
surface runoff, shallow close depression, terraces, dikes, ditches, etc.,
or that reduces the surface slope, will tend to have a direct benefit in
reducing erosion and siltation. Where the channels and/or beds of these
structures are permeable, they will increase the infiltration and recharge
rate and can be designed to intercept and recharge nearly all surface runoff.
Such design can have the desirable effects of adding to groundwater recharge
and storage, reducing flood peaks in nearby streams, and increasing baseflow
of mine seeps and nearby springs and streams. Where acid-producing spoils
are involved, however, this design may greatly enhance the volume and pol-
lution load contained in mine drainage long after backfilling has been
completed, and thus negative effects may result.
A range in possible problem types should be considered in mine planning.
Flexibility should be allowed in selecting optimal restoration techniques.
A technique designed to promote surface runoff and reduce infiltration and
recharge, for example, may help to reduce chemical pollution problems
associated with mining only to increase the suspended solids (sediment)
problem. A combination of remedial measures can be adopted to address such
conflicts. For example, structures can be provided to channel water across
sloping backfill deposits to promote maximum runoff; at the same time, sedi-
ment basins, detention storage structures, etc. can be provided beyond or
along the lower edge of the mine to control siltation. In fact, mine
restoration can be accomplished in stages from the top of upland spoil
regions to the base of the slope and/or near the coal crop. Sediment traps
can be provided by leaving partly backfilled areas along the lower slope
until upland surfaces are largely stabilized by vegetation. Two to three
years may be required to establish a suitable sod. By this scheme, the
lower slopes would be restored last to establish the final continuity of
slope. Current mining practice in hilly regions, however, often requires
that the lower outer slopes first disturbed by mining be backfilled following
a routine schedule specified in mine permits and restored as mining pro-
gresses in the upslope direction. This approach promotes runoff, erosion,
and siltation along lower restored slopes that cannot always be controlled
by diversion ditches and small siltation basins. Commonly, no sediment
control facilities are provided along the base of these slopes.
Some mining permits in more hilly mining regions require diversion
ditches be placed below the coal crop to intercept surface runoff, sediment,
and poor quality mine drainage that may flow through, above, or below a
coal crop barrier (Figure 16), Many of the same problems must be considered
when designing these structures as for highwall diversion ditches, with the
added problem that sheet erosion from a single storm following backfilling
can completely fill such a sediment trap or cause it to be breached. Under
these circumstances, ditches will fail to intercept water and sediment
intended to be conveyed to siltation basins or water treatment facilities.
The position of these diversion ditches with respect to the groundwater
flow systems and stratigraphic sequences must also be considered on a mine-
by-mine basis. A ditch located in a recharge area in a highly permeable
bed rock and/or overburden soil deposits, for example, can leak and fail to
42
-------
^Diversion
gdike
Figure 15.
Slope reduction
reverse benches
1976).
measures using sloped benches,
and concave _slopes (Hittman,
43
-------
Ground
Discharge
Area
Diversion Ditch
water
•V'o^^YS-^^^
Diversion Ditch
Figure 16. Diversion ditches placed below coal crop to control
surface runoff, groundwater runoff, and siltation.
(a) Ditch is in a groundwater recharge area and fails
to collect polluted groundwater for downslope routing
and treatment, (b) Ditch is in groundwater discharge
area below the groundwater flow channels containing
acidic drainage. Acidic drainage can be channeled
to points of treatment and will protect downslope water
supplies and water resources.
44
-------
convey mine water to the intended poinlt
diversion structure may provide little
and water resources and to adjacent
within deeper groundwater flow systems
example, may bypass the diversion ditch
regional groundwater sinks or discharge
and tributaries at lower elevations.
of treatment (Figure 16). Such a
if any protection to downslope land
prjoperty owners. Pollutants contained
and derived from nearby mines, for
entirely and be discharged to
areas located along master streams
be
high
Water directed around the disturbed
turbed area, and water pumped from the
by an adequate-sized pipe or stabilized
further sediment. These waters must
vent the discharge of unacceptably
use of flocculants may be essential tc
quality of these collected waters does
have to be treated to achieve proper
levels. It usually is desirable to
quality separately from waters with o;
treatment will result in requirements
treatment will be more efficient and
Most commonly, poor quality water is
area, water collected from the dis-
open mine cut should be transferred
channels to prevent additions of
directed to settling ponds to pre-
suspended solids or turbidity. The
reducing sediment loads. If the
not meet effluent guidelines, it may
'., alkalinity, manganese, and iron
waters of unacceptable chemical
a high sediment loading. Separate
for multiple treatment basins, but
quantities of reagents may be decreased.
ielated to open-pit locations.
tieat
nly
debris
Usually permanent or semipermanent
to receive all collected waters and tc
These basins must be of adequate size
as well as separation of floating
distance from the receiving stream to
The basins should be constructed with
bottoms. Usually, clay bottoms are
require the use of liners or chemical
problems during sediment removal opers
Details of erosion and sediment
been developed elsewhere (Hittman Assc
Control of Soil Water
Some surface mines in mining
more decades, and still spoil banks
special attempt was made in early minijng
overburden deposits above bed rock
were often mixed with fragmented shale
bed rock in a random manner. The
has increased over the years as shale,
up by mechanical weathering; but the
deposits is still very low when compai|ed
banks observed have a very high
high coefficient of permeability compared
and bed rock disturbed by mining. Al]
infiltration of surface water, which
settling basins can be established
establish a common discharge point.
and must provide for sediment removal
They must be located a sufficient
preclude flooding during high water.
adequate stability and impervious
adequate, although some situations may
sealants (Figure 17). Liners pose
tions.
control planning in surface mining have
ciates, 1976),
districts
have been abandoned for two or
only sparsely revegetated. No
to replace topsoil or unconsolidated
materials. Rather, these materials
siltstone, sandstone, and fireclay
of fine-grained matrix material
siltstone, and clay blocks have broken
nfoisture-holding capacity of these
to the original soil. Many spoil
capacity, high porosity, and
with the original overburden spoil
of the above factors favor the rapid
nlaximizes mine drainage formation as it
are
spcil
percentage
infiltration
-------
Figure 17. Spray application of chemical sealant on side/
bottom surfaces of a coal settling basin.
facilitates groundwater recharge. Backfill procedures that result in in-
complete restoration produce closed surface depressions that also favor
ponding areas and greatly increase infiltration to spoil banks (Figure 18).
A regrading program will help to eliminate depressions and ponding
areas, and it could help to promote more runoff by overland flow, partic-
ularly along steeper slopes. However, the coarse-textured nature of most
bed-rock-derived spoil deposits and their high permeability characteristics
should favor rapid internal drainage and groundwater recharge for years to
come'until a less permeable surface soil is formed. Infiltration and
recharge may be less where thicker glacial drift overburden sediments are
placed above bed rock spoil deposits. However, even here, recharge can be
greatly increased within hummocky spoil deposits over that of initial
premining conditions.
The transpiration losses of soil moisture from sparsely vegetated,
abandoned spoil banks will be far less than for the original vegetation cover.
46
-------
Figure 18. Ponding areas res
backfill proceduies
ulting from incompletely restored
-------
Evergreens and other trees that survived initial transplanting in acid spoil
banks are still relatively small and widely scattered in many areas, despite
their 10 to 30 years of age. Their root systems are restricted as well.
Ground cover between trees is still essentially sparse to nonexistent in some
strip mine areas lacking a soil cover. Poor survival of vegetation and slow
adjustment to some mined areas most likely reflect the acid nature of the
spoil banks and their poor moisture-holding capacity.
The evapotranspiration losses of soil moisture have not been measured
or calculated for these bare spoil materials under the range of climatic
conditions experienced in the eastern coal mine district; but values are ex-
pected to be very low, generally less than 12.7 to 24.4 cm (5 to 10 in.) per
year. Interception and evaporation losses from vegetation is still trivial
in most areas and will not increase until the area is revegetated on an
extensive basis. Some spoil banks abandoned nearly 30 years ago show no
transpiration losses of soil moisture. In time, however, evapotranspiration
consumption of precipitation should begin to approach initial conditions as
a lush vegetation cover is reestablished. The significance of reduced inflow
of water and pollution reduction from mine spoil deposits has not been
established in the literature adequately to make a firm statement about the
total benefits that should be expected by restoration of vegetation. But
reduced inflow of soil water to disturbed land should result in a reduced
volume of mine drainage and, it is hoped, a reduced pollution load.
Soil moisture evapotranspiration losses have been measured near State
College, Pennsylvania, and have been found to range from 63.5 to 71.12 cm
(25 to 28 in.) of annual precipitation. Several hydrologic budget studies
have been completed in central Illinois, and evapotranspiration losses were
found to vary from year to year, as expected (Tables 6, 7, and 8). Illinois
is a slightly warmer region with a lower annual precipitation than Pennsyl-
vania and mixed woodland and farmland vegetation. Although it has not been
established that a reduction in soil moisture (and hence in groundwater
recharge) will result in a reduced pollution load from spoil banks, it is
reasonable to expect that this will be the case. The shallow soil zone may
also act as a partial oxygen sink or sump through the decay of organic
matter and plant root respiration. It has not been shown that this oxygen
uptake mechanism will, in fact, significantly reduce the oxidation rate.
Regrading of abandoned acid spoil banks will not be sufficient to
establish a cover crop of trees or grasses unless other more costly steps
are also taken. Namely, lime or limestone and fertilizer may be required
to promote early and rapid growth. Municipal sewage sludges and effluents
can also serve this same role. Benefits are derived from their water content,
nutrient content, often favorable alkalinity, and the fact that they stimu-
late rapid plant growth.
Left to themselves, acid spoil banks may require 25 to 30 or more years
before evapotranspiration losses increase to 10 to 15 in. (25 to 38 cm) per
year. This goal could be achieved within a 2- to 3-year period with the use
of fertilizer, lime or limestone, sewage effluents and sludges, and seeding
of grass combined with trees. A topsoil dressing would only hasten the revegeta-
tion process. Ultimately, the evapotranspiration rate may be increased to 20 to
48
-------
TABLE 6. MONTHLY AND ANNUAL EVA
OVER HADLEY CREEK BASI
Month 1956
Fiontn E^ , - —
s g s
Jan.
Feb.
Mar. —
Apr. 0.12
May 0.08
June 0.11
July 0.10
Aug. 0.08
Sept. 0.06
Oct. 0.03
Nov. neg.T
Dec. neg.
Annual
Total 23. 8(
*Source: Schicht and Walton, 1961.
tET = soil water and surface water e
s
ET = groundwater evapotranspiration
ET = total evapotranspiration
^Negligible.
POTRANSPIRATION IN INCHES OF WATER
S, 1956-58*
1957 1958
ET ET ET ET ET
g s g
neg. neg.
neg. neg.
neg. neg.
0.09 0.11
0.11 — 0.17
0.23 0.14
0.18 0.14
0.12 0.33
0.08 0.18
0.07
neg.
neg.
1 0.08 24.68
rapo transp ira t ion
t9
-------
TABLE 7. MONTHLY AND ANNUAL EVAPOTRANSPIRATION IN INCHES OF WATER
OVER PANTHER CREEK BASIN, 1951-52, and 1956*
Month
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Annual
Total
1951
ET t ET ET
s g
neg.f
neg.
neg.
0.08
0.27
0.18
0.05
0.34
0.23
0.04
neg.
neg.
23.52 1.19 24.71
1952
ET ET ET
s g
neg.
neg.
neg.
0.13
0.43
0.18
0.47
0 .33
0 . 28
0.19
neg.
neg.
21.93 2.01 23.94
1956
ET ET
s g
neg.
neg.
neg .
0.06
0.11
0 . 12
0.13
0.14
0 . 12
0.06
neg.
neg.
18.01 0.74
ET
18.75
^Source: Schicht and Walton, 1961.
tET = soil water and surface water evapotranspiration
s
ET = groundwater evapotranspiration
o
ET = total evapotranspiration
'I Negligible.
50
-------
TABLE 8. MONTHLY AND ANNUAL EV
OVER GOOSE CREEK BASI
Month
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Annual
Total
*Source
tET =
s
ET =
g
ET =
1955 1956
ETt ET ET ET ET
s g s g
neg.T neg.
neg. neg.
neg. 0.26
0.33 0.55
0.64 0.64
0.66 0.28
0.64 0.24
0.28 0.13
0.10 0.13
0.01 0.03
neg. neg.
neg. neg.
23.10 2.66 25.76 22.09 2.26
: Schicht and Walton, 1961.
soil water and surface water e
groundwater evapotranspiration
total evapotranspiration
^Negligible.
&POTRANSPIRATION IN
N, 1955-58*
INCHES OF WATER
1957
ET ET ET
s g
neg.
neg.
neg.
neg.
0.26
1.04
0.78
0.62
0.40
0.10
neg.
neg.
24.35 21.10 3.20
vapotranspiration
51
1958
ET ET ET ET
s g
neg.
neg.
0.30
1.01
1.16
0.13
0.31
0.66
1.23
24.30
-------
25 in. (50.8 to 63.5 cm) of water per year (Ohio, Pennsylvania, West Virginia
region), which should greatly reduce the pollution load derived from the
region. The remaining pollution load following this revegetation effort may
still greatly exceed the premining condition for many years to come. Other
corrective action will have to be taken to bring about further pollution
abatement.
Figure 19 is offered for planning purposes. It shows the potential
evaporation of surface water from lakes across the United States, based on
computed and measured amounts. The total potential evapotranspiration from
surface, soil water and groundwater sources will differ from the figure shown.
During some seasons of the year, soil moisture deficits may result that
reduce actual evapotranspiration losses below the potential.
Strata Dewatering
Groundwater control for mine excavations may be accomplished either by
dewatering the open pit after the water has come in contact with the highwall
and mine spoil deposits, or by intercepting the water as groundwater within
soil or rock below or adjacent to the mine. Dewatering in advance of inflow
to the open pit has the advantage of eliminating the need to treat the water
where acid reactions are inevitable and water quality standards must be met
in the receiving body of water. For economic reasons, only the most impor-
tant water-yielding deposits might be dewatered adjacent to the mine, as the
objective is to reduce the inflow as much as possible, not to eliminate it
entirely no matter what the cost.
Dewatering to prevent slope failures within unconsolidated overburden
deposits may prove useful where mines are located close to highways, streams,
lakes, buildings, etc. (Terzaghi and Peck, 1967; Coates and Yu, 1977).
However, reductions in pore-water pressures are intended to increase the
shearing resistance of the deposits, not necessarily to reduce water inflows
and water treatment requirements significantly.
Important water-bearing deposits that will contribute significant
volumes of water to mines should be delineated in advance, and their aquifer
and confining bed properties should be determined by appropriate pumping
test procedures. Water level fluctuations should be determined on a sea-
sonal basis along with the proximity of the mine to streams, lakes, and
marshes. Water level changes within surface water bodies also should be
assessed. These water level changes may be entirely natural and not caused
by mining, as often believed or claimed by adjacent landowners; rather they
may be related to seasonal changes or droughts.
Dewatering for pollution control need not be as demanding as dewatering
to aid foundation construction or to protect structures and slopes. Some
pumping will always be required from open pits placed below the water table,
but this can be relatively minor for mines located in poorly permeable
strata. Uncontrolled surface runoff and direct precipitation also must be
pumped on an intermittent basis. An assessment of flood potential would be
52
-------
Figure 19. Average annual evaporation (inches) from shallow lakes
(From U.S. National Weather Service).
-------
appropriate where mines are to be placed on flood plains of streams and
rivers. Flood protection embankments may be desirable when frequent floods
are possible (see Volume 4, Mine Hydrology).
Any unexpected large increase in groundwater flows encountered during
mining will go into temporary storage within the mine pit. Pumps can be
added to control this water as needed. Provisions can be made to intercept
this water within aquifers before it becomes polluted in the mine environ-
ment. However, some estimate will be required in advance to determine the
number and spacing of wells that might be required to reduce groundwater
inflow. This process will include determining the power requirement during
the period of dewatering and selecting the number, spacing, diameter and
depth of wells, casing and screen requirements, and pump size. The potential
cost advantage of intercepting this water as groundwater compared with the
cost of pumping and treating it as mine water should be determined. Pub-
lished literature shows that a considerable range in treatment cost is
possible, depending on water quality encountered and treatment requirements
that must be met. Aquifer dewatering to control high quality water or to
reduce turbidity within mine water may not be justified.
The rate of spread of cones of pumping depression is dictated by a num-
ber of variables, as discussed in Volume 4. These variables include items
such as coefficient of storage and transmissivity of the aquifer, the aquifer
thickness, width and length, the thickness and permeability of confining beds,
the head differences between source beds and aquifers being dewatered, the
pumping rate of individual wells, and the number and spacing of dewatering
wells. The goal in aquifer dewatering is to reduce the potentiometric
surface to or below the level of the mine floor within aquifers that underlie
the mine where groundwater movement is upward, or to reduce the hydraulic
gradient and saturated thickness within aquifers exposed along the highwall.
As an alternative, it may be desirable to control or maintain water
levels within important aquifers adjacent to the mine that are being used for
municipal, irrigation, or industrial purposes. Hydrogeological analyses
similar to those mentioned above would be required if recharge wells were to
be used to create cones of impressions (water level buildups) in the water
table or potentiometric surface, or if sheet piles, grout curtains, or clay
barriers were being considered to impede flow within the aquifer near the
mine highwall (Figures 20 and 21). A line of recharge wells (Figure 20) can
be used to maintain the water levels and yield of nearby production wells.
This system can be used during mining. A clay cutoff barrier (Figure 20) can
prevent excessive loss of groundwaters to the surface mine during and fol-
lowing mining. This system can be used to control groundwater flow and
maintain heads during and following mining. Placement of the clay barrier
against the aquifer exposed along the highwall (Figure 20) can prevent
groundwater losses to highly permeable mine spoil deposits. Sheet piles and
grout cutoff curtains (Figure 21) can be used in unconsolidated overburden
deposits to maintain groundwater levels during and following mining. Thus a
balance can be achieved between maximum coal extraction and conservation by
preserving aquifers and protecting water supplies throughout the mining
process.
54
-------
Confining Bed. ~-^r~
Production
Well
Figure 20. The use of recharge wells
to control drawdown with! i
and to reduce Inflow, pum
that in c, the clay cutof
exposed along the highwal
highly permeable mine spo
(a) and clay cutoff barriers (b and c)
aquifers adjacent to surface mines
jage, and treatment requirements. (Note
barrier is placed against the aquifer
. to prevent groundwater losses to
ul deposits.)
-------
Sheet Piles
(e)
Figure 21. Sheet piles (d) and grout cutoff curtains (e) used in
unconsolidated overburden deposits to maintain ground-
water levels during and following mining. (Note that
sheet piles can be recovered from this situation, where
groundwater levels will recover if backfilled with
less permeable spoil deposits and hydraulic closure is
insured for the mine spoil and aquifer.)
56
-------
The magnitude of the dewatering
length of time it must be continued
depending on the rate at which water
aquifers adjacent to the mine, the fUow
recharge rates. These sources of
dewatering wells.
water
rec uired
procedures
Hydrogeological factors identica
water resource evaluation work can be
possible, hydrogeologic variables
uated using field pumping test
and rock rather than those that rely
cores and drilling cuttings. For
a cone of pumping depression will s
volume of aquifer and confining bed
hydraulics theory, have been demonstrated
hydraulic properties in place on
one compares the radius and volume of
jected to laboratory analyses.
1 to those considered in routine ground-
used for these evaluations. Where
in the analysis should be eval-
that sample large masses of soil
solely on laboratory tests conducted on
both the radius of influence that
to during a pumping test, and the
njaterial that is being evaluated by well
The benefits of determining
: sample sizes should be obvious when
NX, BX, or AX cores typically sub-
example,
pread
The concept of strata dewatering
is developed further in Section 5,
Surface Mine Waters, which discusses
potable water and to dispose of pollu
as a tool in water quality management
Experimental Techniques for Treating
the use of connector wells to control
ted groundwater.
MINE DRAINAGE CONTROL ACTIONS BASED CN THE NATURE OF THE OVERBURDEN
In addition to minimizing the
the other pertinent factor in mine
overburden strata and, in some
important criteria are the presence
those that are convertible to a water
Of greatest concern is the pyrite
strata, and strata permeability
cern is the establishment of the wate|r
strata. Such evaluations are most
a number of Investigations (Emrich,
settings
of
content,
1966;
Establishment of Water Pollution Potential
Evaluation of the water pollution
by considering several groups of data
mineralogical
project that would be required and
greatly from project to project.
can be removed from storage within
rate within these aquifers, and their
must be overcome or balanced out by
drainage
introduction of water into the mine area,
control is the nature of the
the strata under the coal. The
minerals that are water soluble and
soluble form by supplemental reactions.
the occurrence of calcareous
(previously discussed). The immediate con-
pollution potential of the surrounding
cojmplex, but they have been approached by
Lovell et al., 1970).
potential of a stratum can be achieved
data from the strata
easurements of in situ strata
Detailed chemical and
Physical data, especially on n
porosity and permeability
Chemical data on the quality of the waters found during core
drilling and in surface runoff
Data derived from direct laboratory
strata capability to modify waiter
57
and field simulations of
quality.
-------
Chemical and Mineralogical Evaluation of Strata for Water Quality Modifi-
cation Potential—
Selection of strata for testing can probably best be made from drill
samples, preferably cores that have not been comminuted. Each strata should
be identified geologically and mineralogically, depths measured, and samples
stored by chosen interval. Often the drill samples resulting from the ex-
ploratory program (designed for coal seam location and reserve evaluation)
can be utilized. The number of cores selected is site specific, but care
should be taken to include all strata from the surface to several feet below
the lowest coal seam to be mined. Strata variations throughout the mine area
should also be considered. The drill holes frequently provide a measure of
water table levels, including potential capability of water sampling for
analysis. The tests to be made on each strata section should include:
- Mineralogical identification with at least semiquantitative indica-
tion. Commonly this can be accomplished through manual examination
by a skilled mineralogist, supplemented by microscopic and even
x-ray diffraction analysis. Special attention should be given to
identification of sulfide and carbonate (or other alkaline) minerals.
- Chemical analysis for total sulfur, carbonate, and acidity-
alkalinity. In some situations, it may be helpful to perform a
complete chemical inorganic analysis to establish compound format
as limestone, dolomite, existing forms of sulfur (as sulfate, sulfide,
and organic) and forms of iron (as sulfide, sulfate, carbonate,
silicate, etc.). Some strata may show evidence of heavy metal
mineralization, in which case semiquantitative spectrochemical analy-
sis should be made for trace constituents such as manganese, zinc,
cadmium, copper, nickel, etc. There may be regions and/or strata
where evaluation for acute toxic substances at very low levels may
require the use of atomic absorption, neutron activation, or
microprobe procedures (as for arsenic, fluoride, beryllium, mercury,
etc.).
- Special tests, such as the identification of pyrite in a given strata.
It can be most helpful to carry out pyrite grain size and pyrite
crystal format distributions (Caruccio, 1973). In these studies, it
is helpful to relate pyrite occurrence to its mineral associations
and apparent access to water and oxygen. There are no standard
procedures for such studies, and they remain essentially research
approaches. The techniques used for microscopic reflective petro-
graphic measurements are usually applicable to pyrite (ASTM, 1974),
while examinations of thin sections (Mansfield and Spackman, 1965) or
the use of electron microscopy may be justified in some situations.
Establishment of Physical Data on Strata Porosity and Permeability—
Physical data on strata porosity and permeability must be combined with
broader scale hydrologic and geologic data giving evidence of water table
levels, strata permeability, and water flow potential in joints, fracture
zones, and faults (Lovell and Gunnet, 1974, and Volume 4 of this series,
Mine Hydrology).
58
-------
Chemical Data on Natural Waters Assoc
Samples of either groundwater or
area to be disturbed should be analyz
linity, iron (ferrous, feric, total),
bicarbonate, hydroxyl, and conductivi
(American Public Health Association,
sulfate component should be considere 1
should be correlated with its origin.
water sample should be further evalua
could be associated with carbonic aci 1
would have no bearing on water qualit
presence of alkaline components woulc
dation, the existence of alkalinity,
conductivity level can be interpreted
solids, and as a lixiviant factor for
.ated with the Strata—
surface water, or both, taken from the
:d for temperature, pH, acidity, alka-
iluminum, sulfate, manganese, carbonate,
:y, by means of accepted procedures
.975). The presence of any acidic or
as a potential pollution source and
The presence of acidity in a surface
:ed to establish whether the component
or with natural organic acids that
degradation from mining causes. The
indicate a resistance to pyrite oxi-
ind a potential buffering capacity. The
as an indication of total dissolved
percolating waters.
Data Derived from Direct Laboratory a
bility to Modify Water Quality—
Despite various attempts to prov
measurement of water quality degradat
strata, the extensive number of vari
have not led to any generally accepted
procedures have been published by the
1966) to provide a basis for estimating
drainage for permit application.
id Field Simulations of Strata Capa-
Lde direct laboratory and field data for
on potential by various coal-related
)les, and especially the time factor,
procedure. The most conspicuous
Commonwealth of Pennsylvania (Emrich,
quality and quantity of coal mine
Procedures developed by Braley (
are typical. They involve leaching t
to a few months. The tests are of
introduction of oxygen to the reactioi
do not incorporate many field conditi
solubility of pyrite.
Another attempt to simulate the
proposed by Goodwin and Emrich (Emrici
soxhlet extraction that permitted the
water contacting the sample.
proposed
Lovell et al. (1970) have
of limited value because they are
the multifarious variables that affec
and bring about their solution. The
lution potential of coal strata must
geological data of the samples.
aspects; (1) the existence in the st
time of sampling and analysis, and (2
sulfide minerals in situ and under ac
occurring
The presence of naturally
composite status of material that ha;
that results in acidic or alkaline wa
distilled water that shows alkalinity
L949, 1960) and varied by Hall (1963)
sample with distilled water for 24 h
limited significance because (1) the
sites is minimal, and (2) the tests
ins that are found to enhance the
ollution potential of the strata was
1965, 1966) utilizing a modified
introduction of air into the distilled
that these types of evaluations are
unable to relate, maintain, and correlate
t the oxidation of pyrite-coal materials
suggest that any test of the water pol-
je backed by detailed mineralogical and
Furthermore, any such test must involve two
cata of water soluble materials at the
a measure of the oxidation rate of
tive mining conditions.
soluble components would represent a
oxidized or has by nature a composition
ters. Thus a simple leaching test with
or slight acidity would imply that with
59
-------
in situ conditions over recent geologic time: (1) there is little or no
acidic material present in the strata, (2) if any pyritic material is present
there has been little tendency to oxidize, or (3) there is a basic alkalinity
in the strata that has neutralized any existing oxidation products. These
data must be confirmed by detailed strata study, as previously described.
In an effort to make such a test as intensive as possible, a represen-
tative sample of the concerned strata is air dried and crushed to minus 60
mesh or finer. One gram of this sample is mixed with 200 ml freshly boiled,
deionized, distilled water at room termperature for 24 h. The leach mixture
is filtered and the filtrate analyzed for pH, acidity, alkalinity, iron
(ferrous and ferric), sulfate, and conductivity.
A finely ground sample must be used to provide the greatest opportunity
for all soluble material to dissolve. The use of larger particle sizes, as
proposed by others, is biased by making only the limited surface area of a
larger-sized particle available for solution, which will tend to ignore the
overall composition of the strata. The excessive ratio of water to strata
is desirable for achieving the greatest solubility of sparingly soluble
components. The use of specially prepared leaching water is essential to
avoid bias that may develop from the presence of carbonic acid or other
trace components in other types of test waters that could enter the system
from the laboratory air environment. A blank sample of the leach water
should be maintained in the same environment as that during the test, since
water of this quality will absorb carbon dioxide and other acidic gases
common to the laboratory rapidly and give incorrect responses.
The second factor that must be involved in any test of coal strata
pollution potential is some measure of the rate of oxidation of the in situ
components within the test sample. Lovell did preliminary studies of such
an approach, although the results are not published and should be extended.
The test procedure devised sought to establish those conditions that would
provide maximum and rapid oxidation and solubilization of any pyrite con-
tained in the test sample.
The test stratum was crushed to minus 1/4 in. top size and supported in
a glass column. The sample was subject to a continuous spray of the test
lixiviant at a constant rate selected to achieve a constant wetted surface
of all the test particles without column flooding for 24 h. The support
column was left open for free contact to the atmosphere. The system effluent
was collected and sampled at hourly intervals. The leachate was analyzed
for pH, acidity, alkalinity, iron (ferrous and ferric), sulfate, conduc-
tivity, aluminum, calcium, and manganese.
The test lixiviant contained a known standardized synthetic mixture of
ferrous and ferric sulfates to maintain a pH of about 3.0. It also included
a known culture of Thiobacillus ferrooxidans, whose cell count was estab-
lished. Such a solution is a strong lixiviant for pyrite. The final test
data were evaluated to establish a maximum rate of pyrite solubility and
correlated with known data of the test specimens such as pyrite content,
particle size, and format.
60
-------
Another approach, based solely on knowledge of the pyrite content of a
strata sample, is suggested by Smith et al. (1974) and relates closely to
standard soil analysis and classification procedures. This procedure mea-
sures the maximum amount of acidity that might be produced from a coal
stratum by pyrite oxidation without regard to associated environmental ef-
fects. The importance of these effects was discussed in previous sections.
Drainage Control Approaches Using Overburden Segregation
Overburden may include three types of materials: (1) topsoil and ma-
terials conducive to plant growth, (2) clean, nonpolluting material, and (3)
known pollution-forming material. Segregation of these three overburden
materials allows for the most effective planning to prevent long-range pol-
lution and to foster rapid formation of permanent vegetative cover.
Although the location for temporary storage of overburden is basically
determined by economics and by the mining system, care must be given to pile
stability as related to erosion, precipitation, absorption, and overburden
solubilization. When timing and climate make it feasible, a temporary
vegetative cover of the overburden is highly desirable. Surface drainage
from such piles must be collected for treatment and sediment removal—
especially materials that have high pollution-forming potential. In addition
to vegetation of the overburden, other techniques to control runoff include
the use of impervious barriers on or around the waste material. Such bar-
riers may include clay, concrete, asphalt, latex (Tolsman and Johnson,
1973), plastics, or the so-called carbonate bonding (Skelly and Loy, 1973).
Asphalt and concrete are costly. Rubber and plastic are often expensive,
fragile, and generally less than satisfactory. The use of underdrains re-
duces the path of percolating water and leads it from the overburden. The
protective procedures are most commonly applied to stored topsoil and to high
pyrite-containing material rather than to the gross bulk of the overburden.
The most effective preventive control of water quality degradation involves
the rapid replacement and compaction of overburden combined with the con-
struction of diversion ditches to channel surface runoff.
Recently, several manufacturers have made available synthetic polymer,
small-mesh fabrics that can be used in haulroads and drainage construction to
distribute loading, increase stability, and prevent reduction of designed
channel water flows. The potential uses of this material in surface mining
need further evaluation, particularly under field conditions.
Other considerations of overburden storage involve geographical trouble
spots that should be avoided or that involve development of special measures.
Examples are groundwater discharge or recharge areas and locations that are
close to steep slopes.
Topsoils should be segregated and stored at a control location that will
minimize transportation distances for storage and final distribution. They
should be stored to minimize erosion and yet to provide adequate acces-
sibility. In some regions, inadequate topsoil is available, and additional
materials must be secured (occasionally from long distances at substantial
costs). Various types of waste byproducts have been helpfully added to
61
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stored topsoils to increase fertility. Among such substances are sewage
sludge, agricultural wastes from food processing, millorginite, fly ash, and
bag house lime. The presence of toxic components in these additives must be
considered.
As previously discussed, the vegetative cover also serves to control
levels of runoff, percolation, and erosion. In the replacement of these
materials, a knowledge of the groundwater levels and directions of flow that
can be anticipated after reclamation is especially helpful. Compaction is
essential during backfilling and can be very effective in minimizing perco-
lation and groundwater recharge. Soft clays are most effective and usually
available, although in some regions they may have to be transported some
distance to the mine site.
After initial cuts while opening a surface mine, the clean overburden
is preferably placed directly by the dragline, front-end loader, or by
truck haul to final backfill locations. This pattern prevents multihandling
associated with intermediate storage and allows immediate layering and
compaction. Such procedures minimize the development of sedimentation and
contact with water. In some surface mining systems, it may be necessary to
separate large boulders (two ft or more) for placement over or in water
courses to prevent erosion. The use of such boulders are helpful in the toe
or head of hollow fills (see Figure 1).
The segregation of material with high acid-producing potential, the
selective placement of it in non-water-flow areas, and controlled compaction
can help to minimize water degradation. The use of clay or other impervious
barrier covers on top of degrading material during backfilling will limit
the amount of water contacting the material. Opinions vary regarding final
placement of these materials: Some require placement along an unbroken low-
wall barrier, while others prefer that it be placed along a final highwall.
Under any circumstances, the material should be placed at locations that will
minimize potential contact with groundwater. Recommended, but not actual
practice, is to layer such toxic material with a base (such as limestone,
hydrated lime, or bag house lime) during compaction to minimize potential
pyrite oxidation. Toxic strata segregation is required in Pennsylvania and
practised in other regions (southwest Missouri, for example). This same
procedure can also be applied in developing refuse disposal areas. Toxic
material should be covered by a layer of limestone aggregate to avoid
armoring of limestone fragments with iron precipitates and thereby rendering
them inactive for neutralization.
Minimizing Oxidation Conditions
Oxygen (from air) and oxidizing bacteria play a critical role in oxi-
dizing pyrite to water soluble compounds that change water quality. All
water quality control planning during surface mining should center on mini-
mizing the introduction of oxygen into potential contacting waters and in
minimizing favorable conditions for chemical pyrite oxidation and autotrophic
bacteria growth. There are some unusual situations in which deliberate
growth of these bacteria is sought to encourage oxidation and hydrolysis of
water soluble ferric iron.
62
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Recommended techniques for avoiding introduction of oxygen include:
1. Avoid water movement that will cause turbulence or splashing.
2. Minimize contact between water/air interfaces.
3. Design strip pits so that water will flow to a collection sump to
permit its controlled removal from the active mining area. This
may involve the following procedures:
a. Elevation control
b. Development of ditches or water flow channels (these may be
unacceptably costly to develop)
c. Development of channels near the highwall (since water most
commonly originates from the highwall)
d. Avoid sump collection areas that are traversed by moving equip-
ment or that require mine water to percolate through mine spoil
deposits
e. Minimize the size and number of water collection sumps
f. Keep collection sumps drained continuously — do not allow
working pit to collect large volumes of water.
Often, the underground water entering a strip pit via the highwall is of
acceptable quality but is subsequently degraded by further contact with
pyrite. It is generally advisable to introduce lime (hydrated or bag house)
into the pit sump to keep these waters highly alkaline. Such procedures
definitely inhibit pyrite oxidation and are especially helpful in warm
weather, when the high alkaline conditions tend to limit the metabolic pro-
cesses of autotrophic bacteria.
Limestone Treatment of Strip Mine Spoil
Background—
Alkalinity can be added to the system in advance of acid formation to
provide a long-term, if not permanent, solution to the pollution problem de-
rived from strip mine spoils. Limestone quarry waste can be used because it
has a wide range of grain sizes that will insure a large surface area for
reaction. The coarser-grain sizes should be retained near the land surface
to provide a prolonged source of calcite to acid-forming reaction sites.
Quarry waste frequently is less expensive than coarse-grained, screened stone,
and it constitutes a little used byproduct of quarry operations. Most plants
that operate lime kilns also produce significant volumes of stack dust, par-
ticularly where air pollution facilities have been provided. Bag house dust
or flue dust may contain 40 to 60 percent active lime; the remainder is lime-
stone in the fine-grained size.
Parizek and Tarr (1972) and Parizek (1973) explain that limestone should
have many beneficial effects when applied as a top dressing to reclaimed mine
spoil:
1. Limestone should help to neutralize acid water being produced onsite
and precipitate iron and other mineral matter within the spoil
banks, thus eliminating "yellowboy" and other precipitates before
they reach surface water bodies.
63
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2. Soil water should be buffered when exposed to limestone. This
should increase the alkalinity of soil and groundwater and retard or
even eventually eliminate the acid-forming reactions by retarding
the growth of Thiobacillus ferrooxidans, Ferrobacillus ferrooxidans,
Thiobacillus thiooxidans, and other catalytic iron-reducing bacteria.
3. The increased soil pH should favor the rapid regrowth of vegetation,
particularly if fertilizer is added at the time the area is reseeded.
4. The increased plant growth in time (2 to 3 years) should greatly
increase CCL production resulting from plant root respiration and
decaying organic matter derived from annual "dieback" or organic
litter.
5. The increased C02 pressure developed within the organically enriched
soil zone will significantly increase the alkalinity derived from
limestone when compared to the alkalinity produced from bare lime-
stone aggregate exposed to rainfall. The buffer capacity of this
soil water should be increased by nearly three orders of magnitude,
which should be of consequence in abating acid mine drainage or
retarding acid-forming reactions.
Significant results have been documented at a demonstration site under
study in central Pennsylvania (Waddell, et al., 1979; Waddell, 1978). The
long-term benefits of applying a limestone dressing to thick, highly acid-
producing strip mine spoil still have not been adequately researched and
documented, but the study by Waddell et al. (1979) is highly encouraging.
The neutralization process should reach a maximum within a few years
after a lush growth of vegetation is established. This may be achieved in
several ways. Both trees and grasses should be used to establish a dense and
continuous ground cover. Moisture and fertilizer will be required to promote
optimum growth. Both are contained in sewage sludge, which is available from
many communities adjacent to strip mine areas. Liquid sludge can be sprayed
from a central holding pond (temporary plastic-lined basin) on one or more
occasions. A single 2-in (5 cm) application early in the growing season
will be beneficial, but several other applications the same season will speed
the growth process significantly and insure a high degree of survival during
succeeding years. Water contained in the sludge also will aid germination
and early growth. Less accessible areas on steep slopes, etc. also can be
treated using a spray irrigation application method.
Solid sludge may be used as a substitute, but it will have to be spread
by other means, and it may not be as easy to apply to steeper slopes. Dry
sludge costs more, since sewage treatment plant operators are apt to want to
recover dewatering costs by charging for the sludge.
Sewage sludges are superior to commercial fertilizers in that they are
readily available, their disposal constitutes a second environmental problem,
they will greatly aid in mine drainage abatement projects, and they should be
cheaper than commercial fertilizers. Unfortunately, sludge may not always
be available in large enough volumes close to every strip mine.
Limestone quarry waste is preferable to lime because it is cheaper,
available at many limestone quarries, frequently has few other uses, tends to
64
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accumulate at quarry sites, is coarser-grained than lime, and should remain
in soils for many years to come. Agricultural lime, on the other hand, will
be consumed in time and can filter into coarse-grained, highly porous spoil
banks and be lost to the neutralization reaction. Lime and limestone stack
dust or bag house dust may be considered along with quarry waste where
available.
Field Studies—
A demonstration study funded by the Federal Highway Administration to
evaluate the full benefits of this restoration and abatement procedure was
recently completed in Pennsylvania (Parizek, 1971; Waddell, 1978; Waddell
et al., 1979). The limestone surface application method of abating acid
drainage was investigated for spoil and embankment deposits disturbed by
construction of Interstate 80 across part of the Allegheny Front in Centre
County, Pennsylvania. This highway required extensive cut-and-fill opera-
tions through pyrite-bearing strata of Mississippian Age and coal- and pyrite-
bearing strata of Pennsylvanian Age to the west. These cuts and fills
resulted in the production of acidic drainage and pollution problems in
springs and Jonathan Run, a small tributary stream crossed by the interstate
highway. Officials of the Pennsylvania Department of Transportation (Penn
DOT) and Federal Highway Administration (FHA) realized that this situation
could occur throughout much of western Pennsylvania and other States. Hence
they supported the demonstration study in hopes that the techniques involved
might prove useful for reducing or eliminating the production of acidic
drainage at the demonstration site and elsewhere. A proposal to demonstrate
the utility of this important abatement procedure on strip mine spoil had
been turned down previously by State and Federal pollution control agencies
and was long overdue for field evaluation and documentation.
Acid reactions were shown to result within highway embankment valley
fill deposits 20 to 60 m (66 to 197 ft) and approximately 150 m (492 ft)
wide. Excavation waste dumps resulting from extensive highway cuts were also
disposed of in the valley of Jonathan Run. These ranged from 10 to 15 m (32
to 49 ft) high and 30 to 90 m (98 to 295 ft) wide. Other regions of the
valley were filled with 3 m (10 ft) of spoil and used for equipment storage,
repairs, etc. during construction. Following construction, water quality
changes were noted in springs draining into Jonathan Run and in a downstream
recreation lake. Springs whose watersheds were located above the highway-
derived spoil deposits remained good in quality except where influenced by a
nearby coal storage yard.
The demonstration called for both a control site and treatment site so
that the benefits of the treatment could be isolated from seasonal changes in
water quality. Flow systems involved were rather complex and involved sur-
face water that infiltrated the highway spoil, groundwater that was recharged
below and adjacent to the spoil, some of the same groundwater that was
discharged into springs and Jonathan Run, which flowed over and through
spoil deposits.
Water samples were taken for a year before treatment and following ap-
plication of limestone, limeplant flue dust, fertilizer, seed, saw dust and
straw mulch in May 1974. Poor plant survival required reseeding followed
65
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by 6 months of additional monitoring with a vigorous grass cover. The
sampling program terminated on December 30, 1977, or 2 years and 7 months
later.
The study concluded that the fluxes of acidity and sulfate, and thus the
production of acid at the treatment site, decreased by a factor of four after
the treatment was applied (see Figures 22 through 26). The flux of sulfate
at the treatment site has not been above 25,000 kg/day since November 1974,
when the pH reached about 5.5 (See Figure 26). The pH has not increased
above this level, except for random variation around the mean, since that
time (Figure 22).
The pH may be controlled by two counteracting reactions. One is the
neutralization of acid by water that has passed through the treatment layer.
The other is the production of acid, with the reaction rate controlled by the
abiotic oxidation of ferrous iron. As water of pH 6.0 or higher entered the
fill material from the treatment material, the rapid, abiotic production of
acid lowered the pH, resulting in lower reaction rates as the pH decreased.
Eventually the pH will be low enough that, if bacterial catalysis has not
become important, the production of acid will be too slow to exhaust the
buffer capacity of the waters unless the residence time of bicarbonate-
enriched soil and groundwater is very long. The maintenance of the pH at
5.5 at the site since January 1975 suggests that the pH at which bacterial
catalysis becomes important was somewhere below 5.5. Except for one measure-
ment, the lowest pH measured at the site since January 1974 has been about
5.2. The low pH measured could be in error, or it could indicate that the
pH dropped below the point at which bacterial catalysis becomes important.
If this second possibility were the case, the sample should have contained
higher concentrations of sulfate than samples with pH greater than 5.2. But
this was not the case. It appears that the pH at which bacterial catalysis
becomes important is below 5.2. At pH 5.2, the oxidation rate is too slow to
produce enough acid to deplete the buffer capacity of the water during the
time the water remains in the fill material (Waddell, et al., 1979).
The authors of the report concluded that because of the similarity
between the hydrologic and chemical settings in the study area and in many
strip mines, this abatement technique has very good potential for reducing
the production of acid from both active and abandoned strip mines, or any-
where that pyrite-bearing strata are disturbed. Its use is especially
promising where earthmoving equipment is already available at the site and
where sources of waste limeplant flue dust and limestone fragments can be
found nearby.
UTILIZATION OF SETTLING PONDS
Overview
The development of sediment (fine soil particles) and its release from
the surface mine site have great potential for stream degradation and must be
controlled during clearing and grubbing from roadways, spoil piles, and
active mine areas, and during reclamation. During clearing and grubbing the
66
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6.0
5.0
ffl
a.
4.0
3.0
1973 1974
1975 1976
Year
1977 1978
Figure 22. Plot of pH through time for the treatment site (Waddell, et al., 1979)
-------
o>
400.0
60
e
CO
300.0
200.0
100.0
0.0
1973 1974
1975 1976
Year
1977
1978
Figure 23. Plot of sulfate concentration through time for the treatment site
(Waddell, et al., 1979).
-------
ON
300.0
200.0
o
u
cd
o
00
s
S 100.0
0.0
+ + "
1973 1974 1975 1976 1977
Year
1978
Figure 24. Plot of acidity through time for the treatment site
(Waddell, et al., 1979).
-------
6.0 1
4.0
O
H
M
2.0
0.0
1973
1974
1975
Year
1976
1977
Figure 25. Plot of alkalinity through time for the treatment site
(Waddell, et al., 1979) .
-------
0.15e+08
0.10e+08
T3
00
O
GO
0.50e+07 —
0.OOe+00
1973
1974
1975 1976
Year
1977
1978
Figure 26. Plot of sulfate load through time for the treatment site
(Waddell, et al., 1979).
-------
concerns are area perimeter control, erosion on steep slopes, minimization of
the time soil is exposed, improper soil overburden storage, and the reduction
of soil infiltration rates. Roadways contribute to sediment through poor
location, improper construction (including drainage structures such as paved
chutes), inadequate maintenance, lack of cut stabilization, and improper
safety berms. During overburden storage and active mining, the parameters
include drainage access to the streams, distance to the stream, and develop-
ment of fills. Reclamation requires proper grading and stabilization, re-
establishment of drainways and aquifers, and structural stability.
The implementation of sediment contro-1 procedures must include engi-
neering for the specific site, keeping disturbed areas small and exposed for
a minimal time, and application of appropriate soil erosion and sediment con-
trol techniques. Sediment must be kept within the mining site. The control
factors include water flow characteristics (velocity and turbulence) and
particle characteristics (size, shape and density). Control techniques
include vegetative buffers, sediment traps, sediment basins, and the use of
coagulants (metal salts, metal hydroxides, and synthetic polymers). Though
these systems control suspended particles., they also tend to provide addi-
tional opportunity to introduce dissolved solids to the water system, causing
degradation in water quality.
To prevent the development of erosion channels during initial vegetative
growth and to achieve stable slopes and drainage ways, some planning (usually
involving mulches) is necessary. The initial use of grasses and legumes is
favored because of the more rapid cover development, but trees may be
planted subsequently if desired. Frequent monitoring of revegetated areas
may be necessary for months to observe any development of erosion or water
seepage. Should these conditions develop, followup corrective action may be
necessary. There are many interrelated aspects that must be optimized to
achieve an acceptable result. The development of seepage months after
backfilling frequently poses the most difficult problems and may even require
extended water treatment.
Transportation of Water from the Active Mining Pit to the Settling Pond
The generally preferred technique is to maintain water from an active
pit under positive control by pumping rather than by gravity flow. To flow
by gravity, the low wall, which serves as a barrier, must be broken. In
some States (Pennsylvania for example) the low-wall barrier must remain in-
tact to meet regulations, and thus water must be pumped. This is not a
consistent requirement, nor is it fully accepted. Some mine operators object
to the substantial loss of coal remaining in the low-wall barrier. However,
frequently such deposits are highly oxidized and the coal is of inferior
quality. Such coal barriers may tend to be water permeable unless deliber-
ately sealed internally with clay. But, highly compactable and poorly
permeable clay may not be readily available in the region. In the case of
mountain top removal system, the Federal law requires that an outcrop barrier
of sufficient width, consisting of the toe of the lowest coal seam, and its
associated overburden are retained to prevent slides and erosion. However,
72
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the regulatory authority may permit an exemption to the retention of the coal
barrier requirement under certain conditions (P.L. 95-87, Title 30, Chapter
VII, Subchapter K, Section 824.11).
Once outside the mine cut area, the water is transported to the treatment
and/or settling location. This is usually accomplished by flexible hose,
flexible or rigid pipe (usually plastic, but aluminum, steel, or terra cotta
can be used) or trench ditches. When conduits are used, they offer versa-
tility of movement and can readily be transported about the mining area by
pick-up truck. **
Ditches usually should follow natural contours and may be constructed
by backhoe. In some situations, solid rock may be encountered during channel
construction, which may require the use of small (but expensive) explosive
charges. Care must be taken that the trench is impervious and will not allow
the drainage to infiltrate the soil or rock surface. The development of
erosion and introduction of further sediment from the ditches are also of
concern. If this possibility exists, it may be necessary to line the ditch
or to use a conduit. The ditch may be lined with plastic sheeting (about
6-mil or heavier), which is a versatile procedure and relatively inexpensive.
These linings will prevent percolation and prevent erosion. They may be
moved to other locations for reuse. The location and design of these ditches
should take into consideration whether or not it is desirable to introduce
oxygen into the water. This determination becomes part of the design for
chemical treatment, if necessary. Closed piping minimizes introduction of
oxygen into the water, but care must be taken to prevent pipe scaling or
sanding.
Design Considerations for Settling Ponds
Design details for sedimentation ponds have been described elsewhere in
the literature (Hittman Associates, 1976). Some general considerations are
presented here.
Water must be transported to sedimentation ponds to allow solids to
settle. These ponds must be adequate in number and have the capacity and
design to meet suspended solids and turbidity regulations in their effluent.
Thickeners or clarifiers are seldom practical in surface mining operations
because of their high cost and the permanent nature of such installations.
Where applicable, however, such devices generally will achieve superior
results to settling basins. Typically, the sedimentation ponds are located
below the low wall at a location that will be adequate to serve during the
life of the mine. In some cases, the ponds have been located above the
highwall or advancing wall to collect and control surface runoff. This
technique may permit reduced pumping distances and results in the removal of
the ponds during subsequent mining cuts. Among the design aspects of settling
ponds can be a discharge standpipe covered with a screen to trap floating
material. The ponds must be designed to permit periodic removal of silt. In
some cases, it may be better to allow silt to accumulate until the pond is
nearly filled (reducing retention time). At that point, the pond is removed
from service and replaced with a newly constructed pond. The new pond may be
merely an extension of the original pond, or it may be placed at a more
73
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strategic location. The old pond is allowed to dry (by evaporation), it is
completely backfilled, and the surface is revegetated. Complete drying of
the silt is essential since premature backfilling can push the high-moisture-
content fines over the pond sides and possibly result in the introduction of
sediment to the stream. This drying process may take months.
Flocculants and other reagents may have to be introduced to pond influent
to achieve proper settling.
Frequently coal fines, oil, and other debris such as wood will float on
the pond surface and may be discharged with the effluent. This can be
avoided or minimized by the distribution of straw on the pond surface. The
straw will trap the floating material and collect near the discharge area.
The straw can be periodically removed, discarded (buried or burned), and
replaced. The floating straw will remain effective until it becomes water-
logged and tends to sink. Replacement cycles may extend from several days
to weeks.
Use of Flocculants in Settling Ponds
Most sediment resulting from surface runoff in disturbed mine areas con-
tains clay minerals that are characteristically very fine in size (near
colloidal). Their settling behavior would normally be very slow, but these
rates are further decreased (often to the point of near permanent turbidity)
by virtue of negative surface charges. Various surfactant reagents, gen-
erally termed flocculants, can modify these surface charges and permit
particles to agglomerate, forming settleable floes. These reagents vary from
highly soluble, ionizable inorganic salts (such as iron and aluminum chloride)
to starches, glues, and synthetic organic polymers.
Three procedures are required in the use of these reagents: (1) Estab-
lishment of the proper reagent, (2) determination of dosage, and (3) develop-
ment of appropriate procedures to prepare the reagents and apply them
routinely.
Procedures one and two are established empirically by jar tests (Allied
Chemical Corporation, 1975; American Cyanamide, 1973; Anis, 1974; U.S.
Environmental Protection Agency, 1973). The fresh water test sample (Figure
27) is treated with varying concentrations of reagent (0.01 to 100 mg/&) over
a range of adjusted pH values at ambient field temperatures and mixed (slow
stirring is preferable to shaking). The sample is allowed to stand quietly,
and settling rate measurements are taken (Figure 28) and recorded. The
reagents showing the highest settling rates are retested under more carefully
detailed conditions to establish optimum performance. Typically, an inter-
face time curve is plotted as shown in Figure 29.
The preparation of the reagent at appropriate concentrations and mixing
it to attain the critical concentration (according to the manufacturer's
specification) establish the effectiveness of the response. Character-
istically, the dilute reagent solution (0.1 percent or lower) is further
diluted with the water to be treated and then slowly added. The rate of
application is a product of the quantity of water being pumped in per unit of
74
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Figure 27. Fresh water samples in jars,
ready for testing.
75
-------
.V ,* ^X , «,£. „ ,
* , v •>
Figure 28. Settling rate measurements of flocculated suspended solids.
76
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VOLUME OF SETTLED SOLIDS mis.
H-
OQ
C
i-i
(D
VO
tD
(B
*d
13
M
H-
O
OQ
rt rt
H- CD
O
a o
O H
Ml <
tD
Ml
M C
O CD
O fD
O CL
0> 3
rt co
co rt
OQ
-------
time and the desired concentration needed in the water, as determined by,the
jar test. Flocculants can be added by pumping the predetermined concentra-
tion of flocculant solution at the determined rate. The water then proceeds
through a slow flocculation mixer, allowing the floes to form.
The synthetic reagents are long-chained, high molecular weight sub-
stances that are deactivated by high-speed mixing, a long period of mixing
(> 2 min), or a sudden stop in mixing (Morrow, 1974). Mixing of the reagent
with the water to be treated can effectively be accomplished by running the
water through a baffled spillway (McCarthy, 1973). Proper mixing has been
found to be the most important factor affecting the flocculation process.
The treated water is then directed to a settling basin or clarifier for
solid/fluid separation.
These reagents are designed to increase settling rates, and they
generally do not enhance compaction of the settled solids. Detailed appli-
cation of Cyanamid Super Floe 330 to surface drainage containing clays from
coal mining has been detailed (McCarthy, 1973) and is illustrated in
Figure 30.
TREATMENT OF WATERS ASSOCIATED WITH SURFACE MINING
Several approaches can be taken to the treatment of waters collected in
pit areas. The initial decision involves establishment of water quality by
regular monitoring (when feasible) for pH, acidity, iron, and manganese. If
treatment is necessary, there are two basic options: (1) Treatment within
the mining pit, or (2) treatment after removal of the water from the pit.
The former technique, although seldom used, offers many advantages. Pri-
marily, it reduces the amount of pollutant formation by keeping the waters
in an alkaline state. This approach limits any existing unsatisfactory water
quality to that entering the mine, and that quality is frequently satisfac-
tory. This procedure also minimizes pump corrosion.
Minimizing the Introduction of Coal Fines and Silt into Waters During Mining
Techniques should be developed to minimize the amount of coal fines that
is introduced into the water in collection areas. Often the amount of coal
fines introduced into the water is increased if the water is allowed to flow
or accumulate in pit areas used as haulways and traversed with trucks or
other equipment. Where possible, sump areas should be located away from
equipment activity. Sections of drainage ditches traversed by equipment
should be replaced with buried pipe. Once created, settling ponds may be
employed to remove silt and coal fines from water pumped from open mining
cuts. The use of flocculants may also become necessary if concentrations of
clay particles are high. Preventive measures are more desirable than the
construction of settling ponds and the use of flocculants, which may result
in increased total costs.
78
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Figure 30. Flocculated surface waters after clarification from
surface mining operation in the State of Washington.
79
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Water Treatment in the Open Cut
Water quality control in the pit is accomplished by the introduction of
hydrated lime into the water. After chemical reaction, the formation of
sludges and their separation do not pose a problem, since all waters dis-
charged from surface mines must pass through settling basins for sediment
control. The lime may be introduced to the pit water as a slurry or by
dusting the surface using appropriate equipment. In any case, it is the
mixing and solubilization of the lime that become a major concern, since the
water depths in surface mine sumps and cuts are usually (or should be) too
shallow to permit the use of mechanical mixers. Some mixing can be achieved
by intentionally locating the water collection area so it will be traversed
by trucks or other moving equipment. This procedure, however, tends to intro-
duce excessive coal fines and silts into the water. The most satisfactory
procedure is to cycle the collected sump water through a pump, which insures
optimum mixing and efficient use of the lime employed. Such a system permits
the introduction of the alkali by broadcasting over the collection area,
spraying an alkali slurry into the water, or by attaching a small line from
the suction end of the pump to a supply of lime slurry. With this latter
method, the pump serves to introduce the lime slurry and circulate the water
(Grim and Hill, 1974). Another approach is to fill a drum with an alkali
(usually soda ash pellets) and cycle the incoming or sump water through the
reagent. Although effective, this system requires frequent attention and is
subject to neglect.
Another reagent that has seen little use offers great potential—bag
house lime (also known as hot lime or kiln dust). This waste is a byproduct
of limestone calcination that is collected to prevent air pollution. It may
amount to several percent of the daily kiln production, and it constitutes
a disposal problem in itself. In some lime kiln operations, this dust is
buried or pumped underground to the limestone mine or rejected into an
abandoned quarry. Chemically, the composition of this dust may vary widely,
but typically it includes several lime components and ash from the coal fired
during limestone calcination. The basicity components are usually about 60
percent calcium carbonate, 30 percent Ca(OH)2, and 10 percent calcium oxide.
This byproduct is usually available at handling cost ($2.00 per ton). The
economic feasibility of its use depends primarily on transportation costs
from the lime operation to the surface mine, which is strictly a function of
distance. These waste products are of extremely fine sizes (70 percent are
minus 200 mesh), which increase their effectiveness but require bulk
transportation by enclosed carrier. The use of rock dust from pulverized
limestone can be helpful, especially because of its long-term responses. The
rate of response may be limiting.
Treatment of Water after Removal from the Open Cut
Treatment techniques for mine water of unacceptable quality developed
during surface mining utilize the same principles and concepts as applied to
waters from deep mines and abandoned mine sources (Lovell, 1973, Bhatt,
1973b). Because the distrubed area where the water originates is a temporary
and changing location, planning must proceed in accord with equipment
80
-------
portability. Only final settling ponds can be viewed as having any degree
of permanence in most of these systems.
Based on anticipated water flow rates and water quality, the basic unit
operations that are normally incorporated in the mine water treatment process
include:
1. Collection of water and transport to treatment site
2. Neutralization
3. Iron oxidation, if necessary
4. Addition of flocculants, if necessary
5. Solid/fluid separation
6. Controlled release of treated water
7. Disposal of recovered sludge
Most of the engineering concerns methods of reagent introduction,
reagent mixture with the water, and settling pond design. The most commonly
used reagents are hydrated lime, soda ash, and sodium hydroxide. Seldom
does the level of reagent consumption permit bulk reagent purchase and
storage. Thus higher reagent costs and higher labor requirements result from
the use of bagged reagents. Availability of electric power in a surface mine
may be limited, so gasoline-powered generators and hydraulically activated
devices are commonplace. The availability of electrical service is a
convenience and cost advantage both for the treatment facility and for col-
lection pumps.
The use of soda ash briquettes (Kalb, 1975) (see Figure 31) is most
realistic, whereas hydrated lime often creates feeding problems because of
material flow stoppage (hang up from moisture absorption). The briquettes
are loaded in self-feeding, covered hoppers that permit the water flow to
pass through a sluice containing the reagent. Although a commercial device
is available, they may be inexpensively constructed from plywood. The water
quality and flow control the necessary retention time and briquette acces-
sibility. The slow-dissolving briquettes will maintain the pH at the ac-
ceptable levels above 6.0. The labor requirements to ensure continuous and
adequate treatment with briquettes are minimal.
The use of hydrated lime is constrained by portable mechanisms for
metering of solids. Any reagent is most effectively used as a slurry or
solution. Various water-powered devices have been used with small hoppers to
dispense hydrated lime directly into a sluice or ditch carrying mine efflu-
ent. They tend to be unreliable, however, since the reagent absorbs water
and is not introduced uniformly, and it is usually inadequately mixed with
the water. Attempts to house such devices, even with the use of heaters or
heat lamps, are not much more responsive. Figure 32 illustrates such
devices as they are applied in a Maryland operation. More complex devices,
such as the Shirley Mix-0-Meter, provide slurrying and reliable metering
capability to introduce the reagent, but then require a power source. Lime
slurry can also be added to the mine water at the suction end of the pump
used to transport water to the settling ponds, as described in the preceding
section.
81
-------
Figure 31. TraDet hopper and sluice used to
neutralize mine drainage in
surface coal mines.
82
-------
00
Figure 32. Hopper and metering device for introducing hydrated lime into coal mine drainage.
-------
The use of sodium hydroxide, despite its disadvantages (it is costly,
hazardous, and difficult to store), has special advantages in the treatment
of waters in surface mining. Its -advantages are based on the versatility it
derives from its distribution as a concentrated solution. Accordingly, it
may be continuously pumped for accurate dosage control from drums at remote
locations. The advantages, disadvantages, and use of the reagent have been
detailed (Lovell, 1973).
Limestone tends to be unsatisfactory in water treatment under most
conditions experienced in surface mining (Lovell, 1973). Limestone is
frequently cited as being less reactive than hydroxide reagents. This con-
straint is related to limestone's limited solubility and the development of
carbonate-bicarbonate equilibria rather than chemical reactivity. Such
systems often show a limiting pH less than 6.0. However, by adequate system
design to permit removal of carbon dioxide, higher pH levels can be main-
tained. Drainage water containing ferrous ions may be inadequately responsive
when treated with limestone due to solubility products constraints of
ferrous hydroxide. Limestone use requires the construction of a reaction
vessel, such as a rotary drum or flash mixer, to provide continuous mixing of
the limestone with the water. This step not only increases the neutralization
capability of the limestone, but abrasion also removes surface coatings on
the limestone that result from the neutralization reactions. The liberal use
of this least expensive reagent is frequently helpful during several stages
of reclamation, in lining waterways, and even in active pit operations.
Treatment of mine drainage by a combination limestone-lime process has
been shown to offer several advantages over limestone treatment (Wilmoth and
Kennedy, 1976). However, the limitations cited above for the use of lime-
stone still apply.
The need to oxidize ferrous iron as a water treatment step is seldom
experienced in surface mining, although the same principles are applicable as
described elsewhere (Lovell, 1973). Attempts to pond water from active cuts
and cultivate the growth of iron oxidizing bacteria have been reported in
Pennsylvania (see Figure 33). Other techniques attempt to incorporate air
into the water. This goal may be accomplished by creating turbulent flow
through the use of a baffled spillway.
Sludge disposal following alkali treatment also involves the same control
measures previously described (Lovell, 1973). The main factors are adequate
retention time, sludge removal, and final disposal. Figure 34 shows settling
ponds separating ferruginous sludges after lime treatment in an abandoned
Pennsylvania surface mine.
The most critical requirement in surface coal mine drainage treatment
is proper monitoring of the clarified effluent. Beyond the interim grab
samples required by regulating agencies, continuous monitoring is generally
not practiced. Continuous pH monitoring is relatively inexpensive and
reliable, equipment is available, and little maintenance is required. Con-
tinuous pH monitoring provides reliable indications for adequate effluent
quality, since proper pH levels can be related to laboratory grab sample data
84
-------
Figure 33. Ponded mine drainage
designed to cultivate
the growth of iron-
oxidizing bacteria as
a water treatment operation.
85
-------
for alkalinity and dissolved iron. It is also feasible to monitor continu-
ously for suspended solids (or turbi'dity) and for conductivity as a measure
of total dissolved solids.
Alarms can be provided in the continuous monitoring systems that alert
any tendency toward inadequate effluent quality. Further safeguards can be
introduced by the inclusion of a discharge control valve that will close on
a pH signal to prevent the discharge of unacceptable effluents.
Carbonate Rocks Added to Acid Water
The three important reactions in the neutralization process were re-
ported by Barnes and Romberger (1968):
+ 2+
H + CaCO -*• Ca + HCO
log (K250) = +2.0 (1)
H+
log (K250) = +6.4 (2)
03 -»• H20 + C02(g)
log (K250) = +1.5 (3)
The secondary reactions given in equations 2 and 3 take place only below
a pH of about 6.4, but reaction 1 can proceed at every pH up to a point
slightly above pH 8, where solid CaC03 is stable with the solution in
equilibrium at normal atmospheric pressure (pressure of C09 about 10~^'^ atm) .
These reactions would apply in cases where limestone fragments penetrate
the spoil bank and enter standing groundwater near the base of the spoil. In
time, insoluble ferric hydroxide would be precipated out on the surface of
limestone particles. This armoring effect slows further reaction of the
calcium carbonate with the acid, and the neutralization reaction should slow
or might even stop after a short time.
Role of Dilution—
The pH of acid water can be raised both by simple dilution and by
buffering when it is mixed with water containing various concentrations of
86
-------
Figure 34. Solid/fluid settling basins to remove
sludge from lime-treated surface mine
drainage.
87
-------
HCCL . Figure 35 shows the pH change as a function of dilution when the
diluent is free of bicarbonate and has a pH of 7, which might be the case for
rainwater.
The equation for the curves at low initial pH (linear segments of the
curves) is:
PH2 =
+ log (X)
(4)
where pH is given for the two waters, and X is the ratio of the final to
initial volume of water (Barnes and Romberger, 1968).
For example, if 1,000 volumes of water at pH 3 are diluted to a final
volume of 100,000 volumes, X is 100, and the final pH would be 5. The curves
for higher initial pH are complicated by the contribution of H+ by the di-
luent .
Role of Neutralization—
Water containing bicarbonate is much more efficient in neutralizing acid
water than bicarbonate-free water; much less diluent is necessary for neutral-
ization to take place. Equations 5 and 6 are involved (Barnes and Romberger,
1968).
Figure 36 presents a series of diagrams showing for different concentra-
tions of bicarbonate in the diluent the initial and final pH relations as a
function of dilution. Three equations describe these curves:
1.100
o
i-
1.10
LI
0 ppm HCOJ
INITIAL pH
456
FINAL pH
Figure 35.
Effect of dilution on the pH of mine waters
when mixed with bicarbonate-free water with
a pH of 7 (Barnes and Romberger, 1968) .
88
-------
(MH+) final = [
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The final effluent may contain quantities of sulfate (over 250 mg/Jl) ,
suspended solids (5 mg/£, unless it accumulates within the waste rock),
magnesium (125 mg/£ as CaCOo), and total dissolved solids (500 mg/£)(Biesecker
and George, 1966; Hem, I960). Any dilution by ground and surface water soon
will bring the quality of treated water up to acceptable concentrations. Any
neutralization that can be achieved onsite will be an improvement.
These chemical mechanisms can be exploited by the selective placement of
alkaline-producing soil and rock above acid-forming minerals. Such strategy
requires that a mineralogical and geochemical profile be established for the
soil and rock overburden deposits to plan the mining process and select proper
equipment. Calcareous glacial till, loess, outwash, etc. may be stripped
separately from acid-producing bed rock strata. Where glacial drift blankets
bed rock spoil following mining, little or no acid and iron drainage problems
result. However, such may not be the case where spoil deposits are mixed
during the mining process and carbonate rock fragments are not abundant. The
surface area of unconsolidated overburden soils is far greater than that of
fragmented bed rock, hence calcareous shale and thin limestone beds should be
selectively stripped and placed where they will have the greatest benefit in
the backfill (Figures 37 and 38). Often large blocks of marine and fresh-
water limestone are contained in mine spoil. Thin beds of limestone typically
break along bedding and joint planes or part along solution-enlarged openings.
Often these are coated with iron hydroxides and probably are limited in their
bicarbonate-producing potential.
Blocky limestone might be selectively stripped and crushed, and the
aggregate carefully placed near the top of mine spoil to improve the ground-
water quality where acid reactions are inevitable (Figure 39). This added
step taken during mining could go a long way toward reducing mining and post-
mining acid drainage problems.
91
-------
Plant Preparation Wastes
Figure 37. Limestone and calcareous shale placed on top of acid-producing
strata to impede acidic reactions. Top soil restoration
promotes rapid revegetation and productive use of reclaimed
lands.
92
-------
Bedrock Surface^
Acidic
•Leached
Drift
Plant Preparation Wastes
Figure 38. Glacial drift overburden is placed upon bed rock
spoil: the unleached Z5 horizon impedes acid
reactions within underlying rock spoil deposits.
Topsoil is reclaimed to stimulate plant growth
and retain oxygen migration.
93
-------
vo
-C-
Coal Preparation Wastes
Figure 39. Thin, blocky limestone beds crushed to increase surface area and placed above acid-
producing mine spoil and coal plant preparation wastes. Note: No calcareous shale
unit is present in this example.
-------
SECTION 5
EXPERIMENTAL TECHNIQUES FOR TREATING SURFACE MINE WATERS
OVERVIEW
Significant progress has been achieved by numerous researchers experi-
menting with new methods of treating and controlling surface mine waters.
This section presents a brief review of these recent accomplishments. The
discussion that follows organizes current research efforts into three major
groupings: physical/chemical plant processes, chemical field methods, and
physical field methods.
PHYSICAL/CHEMICAL PLANT PROCESSES
Recently, more sophisticated techniques have been applied to physical/
chemical plant processes for the treatment of mine drainage waters. The
treated water is of a near potable quality, and in some instances it has been
used as part of municipal supplies (Kunin, 1974). The processes require much
more elaborate installations than needed for treatment by neutralization, but
in some instances they may be applicable. Two of these processes, ion
exchange and reverse osmosis, are briefly discussed below.
Ion Exchange
The ion exchange process removes the objectionable metal salts and
hydroxides from the mine water by replacement with ions from an ion exchange
resin. As the resin becomes exhausted, replacement capability decreases, and
regeneration of the resin is necessary.
Various forms of ion exchange processes can be used to remove constit-
uents from mine drainage. Either alone or in combination with neutralization,
softening, and aeration, ion exchange can produce water of high quality
suitable for either domestic or industrial use. Indications are that the
sludges and other residues produced by this process may be more amenable to
disposal than those produced by neutralization (Bhatt, 1973a'and b).
Two major limitations exist to the application of this process: (1) The
process requires sophisticated portable equipment that requires continued
maintenance by trained personnel; and (2) the relatively high cost of the
regeneration chemicals makes the process uneconomical compared with
alternative processes after the total solids level exceeds 500 to 1000 mg/&
(Bhatt, 1973a and b).
95
-------
Two criteria can be used in selecting ion exchange processes for the
treatment of mine drainage (Bhatt, 1973a and b):
1. Ability to convert the contaminating soluble ions present in mine
drainage into insoluble forms.
2. Ability to utilize low-cost chemicals as regenerants or to develop
process sequences that allow for the recovery and reuse of the
regenerant.
Reverse Osmosis
The nearly complete removal of metal salts from mine drainage is accom-
plished in reverse osmosis by the movement of the water through a semiperme-
able membrane leaving a concentrated solution of salts. The equipment
involved in this process is extremely elaborate, and many problems have been
encountered when treating acid mine drainage (Blackshaw, 1974). The major
disadvantages of this process include (Bhatt, 1973a and b).
1. Acid mine drainage treatment and brine disposal are costly.
2. Reverse osmosis by itself does not eliminate acid mine drainage
water.
3. Membranes foul and consequently require periodic replacements.
4. Operation with acid solutions required for. the prevention of
scaling makes it necessary to construct the plant of corrosion-
resistant materials that significantly increase capital cost
requirements.
5. Prefiltration of acid mine drainage is required for feed to a
reverse osmosis process unit.
The only reported principal advantage of reverse osmosis for acid mine
drainage treatment is the recovery of nearly potable water as a byproduct
(Bhatt, 1973a and b).
CHEMICAL FIELD METHODS
Three methods are reported under this grouping. They include the use
of soil as a renovation medium, the application of sewage sludge and efflu-
ents, and the use of limestone barriers.
Soil as a Renovation Medium
Calcareous Soils—
Soil leached of carbonate minerals (calcite and dolomite) will not pro-
vide a buffer capacity to acid mine drainage, as outlined previously. Most
residual and transported soil deposits that make up the A and B soil horizons
have been leached of carbonates in humid regions. Calcium carbonate, gypsum,
and other soluble salts can be enriched within the B-Horizon of soils forming
in arid and semi-arid regions, but these occurrences should be rare within
the eastern mining districts.
96
-------
"Soil" by the engineering definition (i.e., any naturally occurring
aggregate of material that can be disaggregated by gentle mechanical means
such as stirring in water) can contain important .reserves of carbonate min-
erals located below the zone of leaching. Loess, glacial till, outwash sand
and gravel, and lacustrine deposits typically are calcareous below the zone
of leaching. These deposits can be identified during prospecting, and
selectively stripped and placed during mining, provided that their presence
and value in neutralizing acid reactions are recognized in premining planning
studies. They can be more effective in offsetting acid reactions than
artificially applied crushed limestone because of the vast surface area that
spoil particles afford compared with crushed aggregate. Glacial deposits,
derived in part from the erosion and transport of calcareous bed rock, typi-
cally contain calcareous minerals in all grain-size fractions and are common
as silt- and clay-size particles.
These soils should be identified and characterized in premining planning
studies and included where possible in mine restoration plans so that they
will give the maximum benefits in offsetting acid reactions or abating acid
mine drainage where formed. The slow leakage and migration of acid mine
drainage into soils of this type can result in long-term treatment benefits
that may not have been anticipated (Figure 40).
Calcareous soils might be exploited in a number of ways. The most
advantageous use of these soils should be as a top dressing on acid-producing
bed rock, where there should be pronounced suppression of the acid-forming
chemical reactions, as explained previously.
If acid mine drainage has been produced and then comes in contact with
calcareous soils naturally or is applied to the soil by deliberate flooding
or spray irrigation (Figure 41), it will only be a matter of time before the
neutralization potential of the soil is consumed and the pollution front
continues to migrate within the soil water and groundwater flow systems.
If surface treatment procedure is adopted, lime application would be re-
quired to maintain a favorable treatment soil environment. A pH adjustment
would result, but the byproduct water would (1) increase in total hardness,
(2) contain sulfates (a byproduct of the acid-forming reactions) unless it
were precipitated as the mineral gypsum, and (3) have a high specific
conductance.
Noncalcareous Soils—
Caution should be exercised when applying highly acidic water to soil and
rock where neutralization reactions are not likely to occur. Many trace
elements and heavy metals can be leached from natural soil and rock deposits
at low pH values. These elements, previously present in trace amounts in soil
water and groundwater, could increase dramatically and seriously contribute
to the total pollution problem. The interaction of acid water with clays,
feldspar, and related minerals can account for partial renovation of acid mine
drainage, which should cause the pollution front to lag behind the actual
groundwater and soil water flow rate.
97
-------
VO
00
Figure 40. Natural abatement of acid mine drainage where acidic
groundwaters come into contact with calcareous soils.
-------
Spray Irrigation
/ V
alcareous silt, sand,
loess, till, etc.
Infiltration Lagoons
1
Calcareous silt, sand,
loess, till, etc.
Figure 41. Application of acid mine drainage to calcareous soils by
spray irrigation (a) and flooding methods (b).
99
-------
Little work has been done to assess the soil's renovation potential for
acid mine drainage. Recent laboratory field experiments at The Pennsylvania
State University show that benefits are possible under some circumstances.
Beers, et al. (1974) tested initial soil columns in the laboratory
through which mine drainage was leached. Rayne and Guernsey soils were
selected to construct 102-cm (40-in ) soil profile columns. These soils are
found extensively in coal-producing regions of Pennsylvania, Ohio, West
Virginia, and Kentucky. Once a week for 42 weeks, 13 cm (5 in ) of acid mine
drainage was added to the columns and leachate samples were tested for a
range in constituents typically found in acid mine drainage.
Table 9 shows selected chemical properties of these two soils. Mine
water showed Increases in pH after it percolated through both soil columns
(Figures 42 and 43). The pH of water applied ranged from 2.6 to 2.8, and
the percolate rose to approximately 4.0 for the Rayne soil and 8.1 for the
Guernsey soil. The researchers conclude that the high effluent pH for the
Guernsey treatment was due primarily to the neutralization of acid by lime-
stone material in the Guernsey subsoil (Table 9). The Rayne soil was not
calcareous but had a near neutral pH within its surface horizon (Table 9).
Both soil columns show the residual effects of agricultural lime applications
during past farming activities to a depth of 23 cm (9 in ). Beers et al.
(1974) conclude that the increase in pH for the Rayne treatment is probably
due to the interaction of the acidity in the water with the ions on the or-
ganic and inorganic exchange complex as well as direct reaction with soil
material. Residual limestone particles in the surface horizons of both soils
may have contributed to the neutralization of acidity in the initial leaching.
They suggest that an equilibrium condition was established during the study
in which the pH was dependent on the soil type. Neutralization capacity
remained constant for the Guernsey soil, whereas it showed a slight decrease
for the Rayne soil after 419 cm (165 in ) of acid water was applied.
The Rayne effluent contained filterable acidity throughout the leaching
study, which increased after the addition of 419 cm (165 in ) of acid water;
whereas the Guernsey effluent showed filterable acidity only during the first
half of the experiment (Figure 43). This response, they conclude, probably
resulted from the saturation of the exchange complex with hydrogen and
aluminum ions, which caused a reduction in the ability of the soil to remove
these acidic ions from solution. The Rayne soil was acidic and must have
relied on cation exchange and hydrolysis reactions to neutralize acidity, and
to a lesser extent on neutralization by limestone fragments (Beers et al.,
1974).
It is important to note that aluminum, manganese, zinc, copper, potassium
and magnesium also were reduced within the soil columns to varying degrees.
The Guernsey soil decreased aluminum content 100 percent throughout the study,
and the Rayne soil showed a significant but varying reduction (Figure 44).
Aluminum increased as the fiterable acidity increased during the 33 weeks or
after application of 419 cm (165 in ) of mine drainage. Thus aluminum solu-
bility increases with soil acidity. For the initially favorable pH Rayne
soil, aluminum reduction is accounted for by absorption on the exchange
100
-------
•s
U>
•5
MG/L CaC03 EQUIVALENT
(B
£3
&.
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ALKALINITY TOTAL ACIDITY
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-------
TABLE 9. SELECTED CHEMICAL PROPERTIES OF RAYNE AND GUERNSEY SOILS*
o
NJ
Soil horizon
and lab no . t
Ap (56-2-1)
B21 (56-2-2)
B22t (56-2-3)
B23 (56-2-4)
B24 (56-2-5)
Depth
(in.)
0-9
9-17
17-26
26-38
38-51
pH
6.1
5.4
4.9
4.8
4.8
Exchangeable cations (meq/lOOg)
Al
0.3
1.2
5.9
6.5
6.5
Ca
9.0
4.7
2.7
1.9
1.3
Mg
0.3
0.1
0.1
0.1
0.1
Na
Rayne
0.06
0.06
0.04
0.04
0.05
K
0.34
0.19
0.21
0.21
0.35
Organic
carbon (%)
1
0
0
0
0
.83
.37
.18
.05
.05
Base
sat. (%)
44.6
21.7
18.2
12.8
10.3
CaC03
equiv. (%)
1.4
0.0
0.0
0.0
0.0
Guernsey
Ap (63-6-1)
B21t (63-6-2)
B22t (63-6-3)
B23t (63-6-4)
B24gt (63-6-5)
Cl (63-6-6)
0-9
9-18
18-23
23-27
27-33
33-40
6.2
4.9
4.2
5.5
6.7
7.4
0.1
3.8
3.5
0.0
0.0
0.0
11.4
9.5
12.7
23.8
26.0
30.8
0.7
0.9
1.1
1.4
1.1
0.7
0.20
0.20
0.20
0.20
0.20
0.20
0.30
0.05
0.40
0.40
0.30
0.20
1
0
0
0
0
0
.84
.14
.11
.12
.18
.13
59.2
39.4
50.7
71.9
100.0
100.0
1.5
0.0
0.0
2.0
5.0
8.8
*Source: Beers et al., 1974.
tPennsylvania State University Soil Characterization Laboratory number.
-------
o _
O _
10 ^
^ ° -
i= CJ ^
13
< O,
t i
1 1 1 1 1 1 1 I I
0 25 50 75 100 125 150 175 200 225
ACID MINE WATER APPLIED (INCHES)
Figure 44. Aluminum content of acid mine water and Rayne soil column
effluents (Source: Beers et al., 1974).
complex until exchange positions become saturated with aluminum ions, whereas
with the higher pH Guernsey soil, aluminum was completely removed as aluminum
hydroxide precipitates (Beers et al., 1974).
Iron concentrations ranged from 150 to 350 mg/S, in the 533 cm (210 in )
of applied mine drainage, but no iron appeared in the percolate. Iron is very
sensitive to pH and Eh conditions, and the researchers report that the soil
columns were aerated enough to oxidize ferrous iron to the ferric state within
the pH ranges encountered (Rayne, pH 4 and Guernsey, pH 8). Iron would have
precipitated as Fe(OH)o or absorbed on exchange sites (Beers et al., 1974).
The role of available oxygen in reducing the ferrous iron content of acid mine
drainage can be appreciated by tracing the migration of mine water within
stream channels. Fe(OH)o precipitates within the streambed reveal a reduction
in dissolved iron. Yellowboy accumulations within spring pools and ground-
water seepage areas also show that oxygen is available to oxidize and
precipitate ferric iron at the groundwater/atmospheric interface.
Manganese removal was similar to that of aluminum. It is also dependent
on pH and Eh, and it is influenced by the availability of carbonate anions
(Krauskopf, 1967). Beers et al. (1974) report that the higher the soil pH
and oxidizing state, the greater the tendency for manganese to precipitate as
a hydroxide (possibly a carbonate) as well as to be absorbed on the exchange
sites (Figure 45). The more acidic Rayne soil removed manganese by absorption
on exchange sites until they become saturated after 152 cm (60 in ) of mine
drainage was applied to the 102-cm (40-in ) long soil columns. After 254 cm
(100 in ) was applied, the manganese content of the Rayne percolate was higher
103
-------
o
in
-> ° _
_J *
o
S o _
UJ "°
Ul
Z__
^J
tn C«J
oJ
RAYNE
ACID MINE WATER
"I 1 1 1 1 1 1 1 1
25 50 75 100 125 150 175 200 225
ACID MINE WATER APPLIED ( INCHES)
Figure 45. Manganese content of acid mine water and Rayne soil
column effluents (Source: Beers et al., 1974).
than that of the applied mine water, which indicates that as the pH fell,
manganese was being stripped from the soil column (Beers et al., 1974)
(Figure 45). This result illustrates an important concept: metals may be
leached from soil and rock by soil water and groundwater flow systems under
low pH conditions even at somewhat remote distances from the mine site.
Zinc removal was similar to that of manganese and is also pH dependent
for the Rayne soil. Zinc concentration declined in the Rayne effluent until
absorption sites were filled; then it increased rapidly and exceeded initial
values in the mine water, revealing that it was being leached from the soil
column as pH values began to decline. The more alkaline Guernsey soil removed
zinc at a fairly steady rate throughout the experiment (Figure 46), probably
as a carbonate or hydroxide precipitate (Krauskopf, 1967; Beers et al., 1974).
Copper content of the effluent from the alkaline Guernsey soil was lower
than that of the applied mine water (100 percent removal), whereas the copper
concentration for the Rayne effluent was nearly twice as great. Removal
rates for copper are also pH dependent. Copper will precipitate as a car-
bonate or hydroxide at high pH (Krauskopf, 1972). Beers et al. (1974) con-
clude that both copper precipitation and possibly absorption reduce copper
concentrations in higher pH Guernsey soils (pH around 8); but copper was
extracted from the Rayne soil which had a pH range of about 4 during the
experiment (Figure 47).
104
-------
ro -]
OJ -
O
2
N
0 25 50 75 100 125 150 175 200 225
ACID MINE WATER APPLIED (INCHES)
Figure 46. Zinc content of acid mine water and Guernsey and Rayne
soil column effluents (Source: Beers et al., 1974).
to
d
in
O
id
— to
CE O
UJ
o o
CJ
q
o
\
ACID MINE WATER
GUERNSEY
T
T
T
1
-i r—i 1 r
25 50 75 100 125 150 175 200 225
ACID MINE WATER APPLIED (INCHES)
Figure 47. Copper content of acid mine water and Guernsey and Rayne
soil column effluents (Source: Beers et al., 1974).
105
-------
Beers et al. (1974) found that the potassium content of the acid water
was decreased by the Guernsey soil for all acid mine water applications,
whereas it was decreased only slightly or not at all by the Rayne soil during
the first three quarters of the study. Later in the study, the potassium
content of Rayne effluent exceeded that of the applied mine water, indicating
that potassium was being leached from the soil. The Rayne soil absorbed less
than the Guernsey because of its smaller cation exchange capacity and greater
competition of H+ and Al for these exchange sites (Figure 48).
Magnesium was retained by both soils at first, but at decreasing rates.
The trend continued for the Rayne soil after 318 cm (125 in ) of mine water
had been applied, whereas the Guernsey soil showed a greater magnesium content
later in the study. By the time 457 cm (180 in ) had been applied, both soils
lost their magnesium retention capacity.
Calcium concentrations also increased in both effluents with time, until
they exceeded applied concentrations (Figure 49). This suggests that calcium
ions were being replaced by hydrogen as well as other ions from the exchange
complex and by a dissolution of CaCO~ from the Guernsey soils (Beers et al.,
1974).
These studies together with other field observations and theory reveal
that natural soil and rock materials can cause a lag in the migration of
dissolved mineral constituents derived from acid mine drainage. The magnitude
of the lag depends on the physical and chemical properties of the soil and
rock involved. In general, the higher the soil pH, the greater is the
tendency for these constituents to be retained within soil and rock. Absorp-
tion processes in general will provide less protection against pollution than
precipitation reactions, because the exchange sites are finite. Once these
sites are filled, pollutants will continue to migrate within the exchange
media. Furthermore, as the soil pH drops, some constituents absorbed pre-
viously can be leached from the exchange media and others stripped from soil
and rock particles for the first time and enriched within the water in con-
centrations greater than before. Precipitation reactions, on the other hand,
can account for the prolonged attenuation of pollutants as precipitates
accumulate in soil and rock. But again, favorable pH and Eh conditions must
be maintained to sustain these reactions and prevent the redissolution of
these precipitates. Application of lime would be required to maintain soil
pH conditions if soils are to be routinely flooded or irrigated as a means of
treating acid mine drainage.
Application of Sewage Sludge and Effluents
Sewage sludge and effluents are alternative sources of nutrients that
provide both organic matter and moisture if used in the liquid form. Demon-
stration studies at The Pennsylvania State University, Fulton County,
Illinois, and elsewhere reveal that repeated applications of sewage sludge
over at least one growing season will greatly stimulate plant growth,
including grasses, evergreens, and deciduous trees.
Prior attempts at revegetating highly acid spoils in Pennsylvania,
Maryland, West Virginia and other selected mining areas in the eastern
district have been unsuccessful because of high acidity, toxic levels of iron,
106
-------
H-
OP
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rt H-
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en d.
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ro a.
I-i
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fD fD
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VO &<
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CALCIUM (MG/L)
•t> ro
§01
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201
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13
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ro
01
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POTASSIUM (MG/L)
2345
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aluminum, and manganese, low moisture content, and extremely high summer sur-
face temperatures (Sopper et al., 1970). These investigators conclude that
treatment with sewage effluent and liquid digested sludge will ameliorate
these conditions (see Figure 50). The slightly alkaline, nutrient-enriched
wastewater can leach acids and toxicants below plant root depth and provide
organic colloids to detoxify the soluble iron, aluminum, and manganese.
Wastewater and sludge also provide the necessary moisture for vegetation sur-
vival and growth. Evaporational cooling also reduces lethal surface temper-
atures of mine spoil, which helps plants gain a roothold in an otherwise
hostile environment.
Table 10 gives the average concentrations of constituents in the sewage
effluent and sludge used during the first 2 years of the Penn State Univ.
demonstration project. Soils used in large bin experiments were extremely
acid (pH 2.0 to 3.0) and remained barren despite 23 years of exposure and
several attempts at revegetation (Sopper et al., 1970). Table 11 shows the
wastewater and sludge irrigation schedule used in their study and the
fertilizer equivalents applied through effluent and sludge treatments.
Tree seedlings were selected according to types that might be used in
mine reforestation work, and these showed a high percentage of survival fol-
lowing 24 weeks of weekly sludge and effluent applications (Table 12) . Growth
of surviving seedlings was noteworthy following a single growing season and
irrigation schedule (Table 13). Grass and legume growth response were also
highly significant. No seedlings in control boxes survived the 2-year study,
whereas a lush growth was obtained for samples receiving a combined applica-
tion of 5 cm (2 in ) of effluent and 5 cm (2 in ) of sludge on a weekly basis.
These demonstration studies also revealed that effluent samples obtained
1.2 m (3.5 ft ) below the spoil surface showed improvement in quality when
compared to control plots (Tables 14 and 15). Sopper et al. (1970) indicate
that the pH of percolate obtained in control boxes receiving natural rainfall
ranged from 2.2 to 3.8 before irrigation treatment, which was well below the
toxic range. During 24 weeks of irrigation, pH increased to 4.06, whereas
other Ions (K, Ca, Mg, Na, Zn, Cu and B) remained higher in the control bins
than in the treated bins. The higher concentrations appear to be the result
of solubilization of native rock by the high acidity of soil water in the
control bins. Irrigation with effluents and sludge leached and diluted the
native salts, and the solubilities of the manganese, iron, aluminum, copper,
and zinc were suppressed by the dual action of the effluent and sludge
alkalinity and the humic precipitation of organic sludge colloids (Sopper
et al., 1970).
These and more recent findings indicate that more toxic mine spoil can
be revegetated, and thereby benefit water quality, by using land applications
of municipal sewage effluent and sludge. The long-term water quality benefits
that may result after effluent and sludge applications are terminated are not as
well documented. However, interception, evapotranspiration, and oxygen uptake
in the shallow root zone will all be increased following revegetation, and
side benefits of water quality improvement are anticipated. This latter
point needs more detailed verification through actual field demonstrations.
108
-------
Figure 50. Barren, acid-producing spoil that fails to support
vegetation (top), and revegetation of the same spoil
following treatment by sewage sludge (bottom) .
Palzo Project, Southern Illinois.
109
-------
TABLE 10. AVERAGE CONCENTRATIONS OF CONSTITUENTS IN THE SEWAGE EFFLUENT
AND SLUDGE USED IN THE PENNSYLVANIA STATE DEMONSTRATION PROJECT*
Constituent
pH
Org-Nt
N03-N
P
K
Ca
Mg
Na
Mn
Fe
Al
Cu
Zn
B
Dry solids
Sewage effluent
(ing /*)
7.2
34.4
6.1
13.7
34.9
16.0
35.2
0.04
0.50
0.90
0.17
0.11
0.36
Sludge
7.6
932
12 5 #
79.6
136.5
33.8
33.8
1.30
14.80
57.5
1.40
1.80
0.40
3200
^Source: Sopper et al., 1970.
tIncludes NH^-N.
^Soluble orthophosphate.
#Total phosphorus.
TABLE 11. FERTILIZER EQUIVALENTS OF EFFLUENT AND SLUDGE TREATMENTS*
2,
1
2
2
in.
in.
in.
in.
Treatment
effluent
effluent and 1 in.
effluent and 2 in.
sludge
Amount
applied
(Ib/acre)
2,000
sludge 9,980
sludge 12,469
11,429
Fertilizer
N
19
46
64
66.5
equivalent
P2o5
6
13
17.6
18.4
(Ib/acre)
K20
8
6
8
7
*Source: Sopper et al., 1970.
Footnote: 1 Ib = 0.373 kilograms.
1 acre = 0.405 hectares.
110
-------
TABLE 12. TREE SEEDLING SURVIVAL RATES* (IN %)
Species
Japanese larch
White spruce
Norway spruce
White pine
European alder
Hybrid poplar
Black locust
Mean (1% sig.)
Control
0
0
0
0
0
0
0
Oa
Treatments
2E
2.5
40
35
62.5
37.5
10
65
36c
1E+1S
0
10
2.5
20
37.5
2.5
82.5
22bc
2E+2S
0
7.5
2.5
12.5
27.5
10
85
21bc
2S
0
0
2.5
0
2.5
10
67.5
llab
Mean
(5% Sig.)
0.5at
11. Sab
8. Sab
19b
21b
6. Sab
60c
*Source: Sopper et al., 1970.
tDuncan's mean separation.
Note: E = Municipal sewage effluent.
S = Municipal sewage sludge.
TABLE 13. AVERAGE HEIGHT GROWTH OF SURVIVING TREE SEEDLINGS* (IN INCHES)
Species
Japanese larch
White pine
Norway spruce
White spruce
European alder
Hybrid poplar
Black locust
Mean
Control
Ot
0
0
0
0
0
0
0
Treatments
2E
0
2.0
2.1
2.2
6.0
13.8
4.3
4.0
1E+1S
0
1.4
2.0
2.1
3.5
0
12.8
3.1
2E+2S
0
3.0
1.9
1.7
2.7
14.4
13.7
5.3
2S
0
0
2.3
0
1.6
11.1
9.9
3.6
*Source: Sopper et al., 1970
tNo surviving seedlings.
Ill
-------
TABLE 14. AVERAGE EFFLUENT CONCENTRATIONS OF pH, Fe, and Al* (mg/jl)
Treatment
Control
2E
1E+1S
2E+2S
2S
A
2.20
2.58
2.43
2.75
2.80
pHt
B
2.18a
2.61bc
2.44ab
4.06d
2.86c
Fet
A
1162+
147
446+
67
117
B
126+
21
61
2
29
Alt
A
477
275
544
165
355
B
248+
57
79
3
61
*Source: Sopper et al., 1970.
tA is pretreatment period; B is treatment period.
^A is average for first 8 weeks and B is average for third 8 weeks.
Note: E = Municipal sewage effluent.
S = Municipal sewage sludge.
TABLE 15. AVERAGE EFFLUENT CONCENTRATIONS OF P, NO -N, Org-N, K, Ca,
Mg, Na, and Mn* (mg/£) 3
Treatment
Control
2E
1E+1S
2E+2S
2S
P
0.029
0.086
0.126
0.149
0.160
N03-N
<1.0
4.8
14.4
50.4
41.1
Org-Nt
7.6
47.8
105.6
105.7
K
108.7
20.4
22.9
18.8
27.3
Ca
44.9
16.7
31.5
41.3
60.5
Mg
115.8
32.8
65.8
31.5
72.0
Na
0.5
15.4
13.2
18.7
18.1
Mn
50.4
15.4
26.8
9.6
29.4
*Sopper et al., 1970.
tIncludes annomiacal nitrogen.
112
-------
In more arid regions, the benefits of sewage effluent and sludge treat-
ment may be less permanent once the application of sludge and/or effluent is
terminated. Capillary effects within the soil can cause the migration of
acidic soil moisture back to the land surface, and a slow reversal in benefits
probably will occur as the buffering capacity of this shallow treatment zone
is depleted.
Some short-term improvements in water quality should be expected from
the application of alkaline sewage sludge to spoil banks. However, the main
impact of using limited amounts of sewage sludge, either in liquid or dried
form, will result from the increased plant responses and evapotranspiration
losses of surface and soil moisture. Other soil additives, namely a dis-
seminated mixture of limestone and mulch, should be considered to bring about
maximum and prolonged beneficial results in abating pollution from strip mine
spoils.
Use of Limestone Barriers
Water quality can be improved within springs and streams using limestone
barriers placed within the spring or creek. Rather ideal field conditions
must be met for this mine drainage pollution abatement technique to apply.
The barrier should contain rather pure limestone that will react with acidic
drainage, and grain sizes should be selected to provide a high surface area
and at the same time allow for sufficient leakage to preclude erosion of the
leaky barrier by flood flows. Furthermore, dissolved iron concentrations
must be relatively low to preclude the armoring of limestone fragments in the
barrier by iron precipitates.
Theoretical calculations by Pearson and McDonald (1975) previously
showed that the pH adjustments that can be achieved within the barriers
depend on many factors, including:
1. Grain size and purity of barrier material used.
2. Velocity of flow through the barrier, or contact time between
the limestone and acidic drainage.
3. Iron content of water being neutralized.
Study of the theory involved (which must still be tested under various
streamflow and water quality conditions to determine its full utility) shows
that a buffer capacity can be added to the stream directly to raise the pH
and reduce the acidity flux of surface water directed through the barrier.
A major constraint to the application of this abatement method is posed
by the infiltration capacity of the barrier. A high permeability will result
in rapid throughflow and limited treatment. Finer-grained barrier deposits
can result in the frequent plugging of the barrier face and frequent over-
topping of the barrier by flood waters, again with little benefit of treat-
ment. Sediment, organic matter, and precipitates in suspension will quickly
form a filter cake on the upstream face of the barrier, thereby reducing its
effectiveness. The method appears to apply best to constant flows of rather
favorable quality. Thus excess flood waters may have to be passed around the
113
-------
barrier, or the structure may have to be placed so as to tap and treat a
portion of the base flow following siltation and iron removal.
Equations 5 through 8 of this report show that the pH of acid water can
be raised by simple dilution and buffering when it is mixed with water con-
taining bicarbonate. Bicarbonate-enriched water is more efficient in
neutralizing acidic water than a simple mixing of bicarbonate-free water with
acid water of a lower pH (equation 4).
Pure calcite (CaCO.,) could be expected to raise the pH of pure rain
water to 8.3 given a prolonged contact time. However, this represents a
laboratory idealization that rarely can be met under field circumstances.
Construction of a Test Barrier—
Spring 004 on Jonathan Run, Centre County, Pennsylvania, was selected
for a brief field experiment using the limestone barrier method. This spring
was being monitored for water quality responses resulting from a limestone/
limeplant flue dust method of acid drainage reduction described previously
(Waddell et al., 1979).
Various codes of crushed limestone aggregate (Table 16) supplied by
Marblehead Limestone Company, Pleasant Gap, Pennsylvania, were subjected to
laboratory permeability tests by Herman (1977) to select an aggregate of fine
grain size but of sufficient permeability to accommodate a portion of or all
of Spring 004 flows. Several years of gaging record were available and
guided the selection of the aggregate.
A 20-ton, Code 72 Valentine limestone barrier was first placed below
the spring on May 20, 1977; but the permeability and cross-sectional area of
the barrier were insufficient to allow the full discharge of the spring to
flow through the barrier. Erosion of barrier deposits during construction
increased the length of deposit through which flow had to take place. A
clay dike had to be built to force the water through the barrier. Because of
budget constraints, insufficient clay was available to raise this dike to the
necessary level. A significant portion of the flow topped the dike, bypassed
the barrier, and hence was not neutralized.
On May 29, 1977, an additional 20 tons of Valentine limestone were
added to the barrier, and the dike was raised to increase the upstream pool
elevation and hydraulic gradient within the barrier. Eventually this barrier
was also breached by high flows. Ideal conditions will be achieved when the
entire water flow from Spring 004 passes through the limestone barrier and
only peak flows are allowed to bypass it. Some leakage from the original
pool floor and sides has probably occurred and bypassed the barrier as well.
But a more serious problem has resulted from selection of a too fine grain
size. As spring flow increased, some water bypassed the barrier by entering
a spillway in the dike provided to protect the dike and barrier against ero-
sion by flood waters. Eventually, the barrier was again topped, despite
repeated attempts to repair the barrier. A more elaborate design and con-
struction project should eliminate this difficulty.
114
-------
TABLE 16. GRAIN-SIZE DISTRIBUTION FOR THREE CODES OF VALENTINE
LIMESTONE PROVIDED BY THE MARBLEHEAD LIMESTONE COMPANY*
Code of limestone
Code 55 Stone
(3/8" x 0")
Code 60 stone
(1/4" x 0")
Code 72 stone
(1/4" x 20 mesh)
Screen
Number
3/8"
#4
#8
#16
#30
#50
#100
#200
1/4"
1/8"
#8
#16
#20
#30
#50
#100
#200
1/4"
#4
#6
#8
#12
#16
#20
size
Inch
0.375
0.185
0.093
0.046
0.023
0.012
0.006
0.003
0.250
0.125
0.093
0.046
0.033
0.023
0.012
0.006
0.003
0.250
0.185
0.131
0.093
0.065
0.046
0.033
Passing
%
98.94
70.48
44.43
26.79
16.52
10.26
5.97
1.35
99.58
77.99
65.25
36.65
26.34
21.90
11.13
5.61
1.16
96.68
92.63
85.64
66.63
38.56
16.61
5.74
* From J. Herman in Waddell et al., 1979.
115
-------
The erosion problem became more serious as time passed and as suspended
organic matter filtered out on the upstream face of the barrier, thereby
reducing its infiltration rate and permeability. Only a few tenths-of-meter
separated the barrier from the spring outlet. An algae mat also developed on
the face of the barrier, further reducing its permeability. A favorable
infiltration rate probably can be maintained by increasing the grain size, and
hence the permeability, of the barrier. This project can be done in stages
so that the upper section of the barrier is most permeable, with the lower
section containing the finer-grained aggregate. Flood flows should be
accommodated in this way by the barrier, and low flows should be channeled
through the finer-grained portions of the barrier (Waddell &t al., 1979).
Early chemical data obtained above and below the barrier were encouraging
and revealed that a very favorable rise in pH and bicarbonate was being
achieved by the barrier gravels selected (Table 17). Their high surface area,
purity, and the prolonged contact time with the water are beneficial to the
neutralization reactions.
Immediate results were determined by J. Herman (1977). The pH was
measured the same day the barrier was constructed. For water just above the
barrier, pH was 4.90, and for water flowing out of the toe of the barrier,
pH was 7.75. Water sampling was done at sites in the stream above and below
the barrier at different points 1 and 2 weeks after the barrier was con-
structed (see Table 17).
Field demonstrations are justified for this instream pollution abatement
technique. It may be difficult to treat major streams using this procedure,
but at least it may be possible to channel portions of streams through such
barriers to allow reduction of iron and sediment.
PHYSICAL FIELD METHODS
Three methods are reported under this grouping: the development of water
storage areas in lieu of direct release, the use of connector wells to control
potable groundwater, and the use of connector wells to dispose of polluted
groundwater.
Development of Water Storage Areas in Lieu of Direct Release
In some situations, the development of permanent water storage areas may
be preferred over the direct release of the mine waters to the watershed
during reclamation. These conditions must become part of the original mine
plan and be approved by the appropriate government regulatory bodies with the
consent of the landowner. The objectives normally incorporate the creation
of recreational lakes, planned community developments (including golf
courses), or water sources for agricultural purposes (cattle, irrigation,
etc.).
The conditions favorable to such planning include the availability of an
adequate water source (quantity and quality), appropriate geohydrological
conditions (water table levels), and natural terrain features (especially
116
-------
TABLE 17. CHEMICAL WATER QUALITY DATA OBTAINED ABOVE AND
BELOW THE LIMESTONE BARRIER*
Sampling time and site
PH
Specific
conductivity
(micromhos)
Bicarbonate
(ing/ A)
Average from weekly readings for
April:
021
022
023
024
One week
021
022
023
024
Two weeks
021
022
023
024
: the spring
: stream, where head
of barrier is now
: stream, where toe
of barrier is now
: stream, where it
flows into the lake
after the barrier:
after the barrier:
4.77
4.90
5.07
4.95
4.44
7.74
4.39
5.00
4.92
7.87
4.45
155
162
164
159
150
250
163
138
149
253
-~ —
2.24
0.75
2.99
1.12
2.24
1.12
59.36
0
* From J. Herman in Waddell et al, 1979.
117
-------
elevation). In general, the available water quality must be satisfactory or
provision must be made for continuous treatment. The ponding of waters may
reduce degradation of water quality through reduced exposure to mineral
surfaces, strata coverage, reduced oxygen availability, the presence of
calcareous strata, or controlled water quality planning.
Among the planning requirements are a detailed knowledge of the local
terrain, geology, geohydrology, stratigraphy, water quality, and limnology,
as previously described. Provision must be made to ensure the water-holding
capacity of the ponded area; evidence must be presented that the water quality
can be satisfactorily maintained; provision must be made for the 10-year,
24-h precipitation event (including spillways, provision against localized
erosion, and maintenance of terrain stability) and physical stability must
be provided for any man-made dam structure.
Several permanent water storage areas have been developed, and others
are planned. In Somerset County, Pennsylvania, a newly initiated coal sur-
face mine operation is destined to become an elaborately planned housing
development, centering around a large, freshwater lake fed by surface and
underground water sources encompassing the disturbed area. In Oklahoma coal
mining districts, where precipitation levels are low, reclaimed areas are
planned to develop small, shallow ponds to provide drinking water for cattle.
The slopes are stabilized, vegetated to control erosion, and contoured to
provide safe access for large animals (Figure 51).
Other documented examples are: (1) The Elcampton project in Clearfield
County, Pennsylvania, where a large pond holds drainage from an abandoned
surface mine to observe and hopefully improve water quality (little change
has been reported), and (2) The Sheban project (perhaps the most publicized
effort) in eastern Ohio in 1965 (Hall, 1965). In the latter project,
permeability occurred through the impacted spoil, producing unacceptable ef-
fluents. Over the years, the effluent quality has improved, but the
approach, without modification, would not meet current regulations. Other
studies are documented by Riley (1965) and Campbell et al. (1965).
Use of Connector Wells to Control Groundwater
Applications—
Connector wells or gravity wells (Parizek, 1971; Parizek and Tarr, 1972;
Parizek, 1974) could be used to reduce the volume of water that comes into
contact with rocks disturbed by mining in several ways. Connector wells have
their best potential, under favorable conditions, in controlling leakage
into deep mines. They may also be used in strip mining regions_under
restricted conditions to reduce the amount of groundwater that enters strip
mine spoil and auger holes from highwalls, unmined coal, and truncated
aquifers (Figure 52). Where strip mines collar hill sides or are located
in recharged areas, but uplands are still intact and are underlaid by pro-
ductive aquifers that are located above the coal bed, connector wells should
be beneficial in diverting groundwater from spoil banks before it becomes
contaminated (Figure 52) . The connector well concept is predicated on the
assumption that a significant reduction in water entering either deep mines
or spoil banks will result in a reduction in the volume of mine drainage
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Hf ^&_ /• "'Jjf^ ,*&, tysir? S. •( ^ *~- *A^ r .$• •s'Jr ^ ^
Figure 51. Reclaimed surface mine with vegetated area and
contouring to provide safe pond slopes for large
animals.
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Connector
Wells
Aquifer 1.-.
, Mine Spoi
Confining
Bed
Potentiometric Surface../
Aquifer 2
Aquifer 2
Figure 52.
1 = Original water table configuration
2 = Final water table configuration
Connector wells used to reduce inflow of
groundwater to surface mines.
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produced and a reduction in the total pollution load contained in the
drainage. This is the principal objective of the demonstration project
designed by Parizek (1974)—namely, to document the extent to which the pol-
lution load will be reduced by the use of gravity connector wells. A
feasibility study has been conducted by Schubert (1978) that shows
the amount of groundwater that might be intercepted by connector wells
under one set of hydrogeological conditions in central Pennsylvania.
For a connector well method to be effective, several hydrogeologic re-
quirements must be satisfied:
1. A relatively productive aquifer should underlie a hilltop or upland
that has not been completely strip mined. This may be sandstone,
siltstone, or even the remaining coal bed, outwash sand and gravel,
or other unconsolidated deposits. Or if other coal seams in the
hilltop have been mined, mine water should be of good quality and
connector wells should be used to prevent groundwater inflow to
strip mines lower on the slope that are likely to produce mine
drainage of poor quality.
2. The upper aquifer should still contain an appreciable quantity of
groundwater despite the strip mine developed around or along the
hill, and groundwater should discharge from the aquifer through
the highwall to the strip mine environment. This need not be true
for many strip mines in the eastern coalfields where the truncated
aquifer may be essentially dewatered.
3. A deep sandstone or rather permeable aquifer should underlie the
hill that has a potentiometric surface that is lower in elevation
than that of the overlying aquifer.
4. Zones of fracture concentration within bed rock revealed by
fracture traces and lineaments should be recognizable within the
upland. Intersecting zones of fracture concentration should be used
to locate gravity connector wells with maximum yields and with
maximum recharge rates. Only a few highly efficient wells will be
required to drain potable water from the overlying aquifers compared
to the number that might be required if drilling were done on a grid.
5. The quality of groundwater for the shallow source bed and deep
aquifer should be compatible to prevent the plugging of the well
bore and aquifer by iron and/or other precipitates.
6. The coal remaining beneath the upland aquifer should not be slated
for mining in the near future unless the benefits derived from the
connector wells exceed the costs.
Desirable aspects of this abatement scheme are that (1) the dewatering
system will work by gravity for an indefinite period, (2) it salvages potable
groundwater than can be reclaimed for later use either from the shallow
source bed or deep aquifer being recharged, and (3) the method should be
relatively inexpensive under appropriate field conditions. Aquifers con-
taining potable groundwater should not be polluted by this abatement tech-
nique, provided that connector wells are properly designed (Parizek and Tarr,
1972; Parizek, 1974).
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Evaluation Technique—
The presence of relatively productive aquifers beneath hilltops must be
established for each mine within a given watershed. Isolated hilltops and
uplands not likely to be stripped in the future but already stripped along
the crop can be examined for their stratigraphy, structure, aquifer potential,
etc. If highwalls are no longer available for study, fracture trace mapping,
test drilling, and pumping test programs can be conducted to define the hydro-
geologic setting. One to two test holes per mine site may be all that are
required to evaluate the suitability of the method.
The presence and favorable head relationship for the deep aquifer system
should be established during the same drilling program. Water samples can be
obtained from both aquifers to establish their chemical compatibility. If
precipitation reactions are inevitable near the well bore, maintenance and
rehabilitation costs may prove to be excessive in order to maintain favorable
recharge rates for the lower aquifer.
The use of connector wells to control potable groundwater should be
applicable within some watersheds, where it will provide at least some local
relief. But the method will be limited in use to unmined and mined upland
settings where it is difficult to prevent groundwater contact with spoil
deposits using other techniques, and where highwall seepage volumes are
appreciable. Grading and channeling to promote runoff across mined out and
restored intervals from these uplands will help to reduce the pollution
load, but these practices alone will not eliminate groundwater flow to spoil
deposits. A line of connector wells placed parallel to the former highwall,
on the other hand, may prove to be a highly effective pollution abatement
procedure.
Use of Connector Wells to Dispose of Polluted Groundwater
Applications—
Aquifers beneath strip mines and possible deep mines in selected water-
sheds have been polluted by coal mine drainage in a number of locations.
Hillside discharges of acid mine drainage located below mined-out coal beds
and controlled by zones of fracture concentration, stratigraphic sequence,
and colluvial and alluvial confining beds and polluted flowing wells reveal
that this is the case. An alternative connector well abatement scheme to
reduce pollution within selected upland tributaries is possible.
Polluted water contained within aquifers beneath mines might be
drained by gravity into deep confined aquifers that provide avenues for
regional groundwater movement and within aquifer neutralization. This abate-
ment procedure should be considered only if one of the following criteria is
met:
1. The deep aquifers are confined and contain brines or other poor
quality water and hence will not be adversely polluted in the
process;
2. The deep aquifers contain sufficient alkalinity to neutralize
acid mine water intentionally recharged to the aquifers;
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3. The deep aquifers are already extensively polluted by mine drainage
beneath the watershed, but groundwater flow is such as to favor
the subsurface transport of this drainage to adjacent regions where
alkalinity is available to bring about complete neutralization.
Neutralization should be complete before this mine water is again
discharged to land surface along major river valleys. By this
scheme, the aquifer system may be used as a "pipeline" for trans-
mitting polluted mine drainage to points of treatment within the
aquifer or to polluted aquifers where it is desirable to maintain
or re-establish water quality in the smaller watershed to protect
an existing public water supply or other important water use. The
following example is offered to illustrate the concept.
Example—
The mountaintop Burgoon Sandstone is believed to underlie Licking Creek
watershed in Clarion County, Pennsylvania. It is the shallowest possible
candidate aquifer that could be used in such a scheme. However, water quality
conditions have not yet been adequately defined for this aquifer system to
establish which of the three possibilities listed above might apply. Pre-
liminary data collected by U.S. Geological Survey personnel working in the
Clarion River drainage basin suggest that portions of this aquifer system
indeed contain brine or brackish groundwater and some alkalinity. Alkalinity
may be derived from the overlying Vanport limestone and calcareous shales
where they are well developed and where groundwater flows through these
calcareous deposits and into the deep sandstone (Figure 53). The alkalinity
source may be located either in Licking Creek or in adjacent watersheds. In
either case, neutralization of mine drainage should result within the deep
aquifer system as long as the two waters are mixed before being discharged to
the Clarion River. Neutralization reactions accompanying groundwater flow
result in hard, sulfate-enriched waters with favorable pH. Iron may precipi-
tate out on joint and mineral grain surfaces.
Of the three cases listed above, items 2 and 3 are more likely to apply
for the Licking Creek region. The principal benefit would be a reduction in
the pollution load of Licking Creek, a tributary of the Clarion River. How-
ever, for this hypothetical example, no public water supplies are developed
from Licking Creek; hence more general water quality improvements resulting
within the creek may not justify the possible pollution damage that may be
caused within portions of the local deep aquifer system using such a con-
nector well system.
This abatement scheme differs from the one where water is made to bypass
the mine environment, in that acid mine drainage already produced would be
fed by gravity into underlying aquifers either for storage or treatment
(Figure 53). The prolonged success of the method would be insured if
neutralization could be relied on within the aquifer rather than around the
connector well bore. Iron would have to be kept in solution during the
drainage and recharge process until alkaline and acid water were mixed within
the confined aquifer some distance from the connector well. Natural alka-
linity and buffer capacity contained within a segment of the flow system may
be added to the deep aquifer somewhat distant from the connector well
locations.
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N3
"5
fc^S
Acidic Mine Spoil
Mr \
Acidic Drainage
/ / '* t
.Acidtc Drainage
Li mestone,Calcareo us .'Shale
Alkaline Ground Water ..
Flow Lines
Figure 53. Alkaline groundwater contained in deep aquifers underlying acid-mine-
drainage-producing mines lacking other sources of alkalinity.
-------
Byproducts of acid neutralization (SO,, etc.) would still be maintained
in solution and eventually be discharged from the aquifer system; but acidity,
iron, and other mineral species precipitated as a result of the neutralization
process would be retained within the aquifer. If carefully programmed in
advance, long-term reduction of aquifer permeabilities might be insignificant,
but a significant and long-term water quality improvement might be achieved
within selected watersheds where no other pollution abatement procedure is
economically feasible.
Evaluation Technique—
To exploit such deep flow systems, the aquifer system would have to be
investigated in some detail to establish regional patterns of flow and
regional water quality variations within the deep aquifer. Both a productive
sandstone beneath the strip mine (the source bed containing acid mine drain-
age) and a deep aquifer must be present, and both must have favorable head
and yield characteristics, as were required for the other system described
above. Water qualities must be compatible at least near the connector wells
to avoid the rapid plugging of the borehole-aquifer interface by iron and
other precipitates. And ideally, the deep aquifer should contain alkaline
groundwater entrained within the flow system from an adjacent region, or
derived locally from the deep aquifer. Alkalinity may be derived either from
well-developed limestone, calcareous shales and glacial drift located above
the deep aquifer in its recharge area, or from calcareous rocks, located
below the deep aquifer where the direction of groundwater flow is upward'.
A regional groundwater study would be required to define such hydro-
logical and geochemical systems. The aquifer thickness, distribution,
potentiometric surfaces, and water quality would have to be established within
and beyond the bounds of individual mines and tributary watersheds. A care-
fully designed test drilling program might also be required to define aquifer
hydraulic properties and reliable head and groundwater quality data.
The benefits of this untested, natural abatement system could be far-
reaching if the pollution load could be removed at favorable locations within
selected watersheds on a permanent basis and at minimal costs. Byproducts
of neutralization would be stored and disposed of in deep aquifers, natural
sources of alkalinity would be exploited, and gravity would serve as the
power supply! Deep well injection of acid mine drainage as a means of
ultimate disposal appears to have severe limitations. The method is not
likely to win widespread support, either by the mining industry or by
regulatory agencies.
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SECTION 6
MONITORING PROGRAMS
INTRODUCTION
Monitoring is required during all phases of mine planning, mining, and
restoration. It can include measurements of seasonal changes in groundwater
levels, streamflow, and water quality in wells and springs that might be im-
pacted by mining. Erosion, siltation, changes in water levels, etc. can be
monitored during site exploration studies, during mining, and following
mining. Observation of anomalous behavior of elements of natural systems will
reveal the parts of these systems that are incompletely understood. This may
justify an expanded exploration program, additional theoretical analyses, or
more careful observation.
Abrupt changes in groundwater levels, changes in pumping rates needed to
control water, spring and tributary streamflow, and water quality changes
should be noted to distinguish perturbations induced by mining from naturally
occurring seasonal changes in the system. These changes follow seasonal
patterns that are part of a background that must be isolated from impacts on
these systems induced by mining. Appropriate detailed records collected by
qualified individuals will be useful in protecting mining companies and
adjacent landowners alike from litigation. These records will allow for re-
investigation and better definition of elements of the system that do not
appear to behave according to initial forecasts. Forecast models thereby can
be modified and actual field conditions more adequately defined.
Post-mining monitoring will be resisted by the industry if it feels it
will be damaged by long-term, adverse changes in the system shown to be
induced by surface mining. However, irrelevant aspects of mining laws that
have no bearing on local field circumstances but are required by State
and Federal laws can be logically fought when facts are available. Also, the
benefits of many mine restoration projects, acid forecasts, erosion forecasts,
drawdown forecasts, etc. can be studied and field documented. These data can
guide the planning, engineering, and regulation of new mines that will be
more' in harmony with local circumstances. This can be of benefit to all in
the long run and is the only way that an understanding will be gained of the
workings of geochemical and hydrogeological systems stressed by surface mining
under variable geological, topographical, geochemical, climatic, and mining
conditions.
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MONITORING WELLS
Selected exploratory borings should be retained for observing water level
and water quality changes with season of the year, for noting drawdown fol-
lowing the start of mining, for checking water level responses following back-
filling, etc. In many cases, these first-noted changes in water levels or
quality can be compared with predicted or computed water level and quality
changes determined by analytical or modeling means to see if predicted
responses agree with observed responses. Modification in assumed values for
recharge, permeability, storage, vertical leakages, etc. can be made in the
forecast models so that new water level decline forecasts will be in better
agreement with what was observed.
Several State mining laws currently require that all coal test holes be
plugged or backfilled immediately following exploration. This backfill
requirement is counterproductive to hydrogeological and geochemical monitoring
needs and to possible followup hydrogeological investigations. All holes are
to be plugged, when in fact, selected borings should be left open to monitor
water level changes, conduct pumping tests, observe drawdowns and water
quality changes, etc. The value of open test holes should be recognized by
regulatory agencies and factored into the design and implementation of mining
regulations as well as into mine planning. However, the intent to use these
boreholes should be followed up with early action or backfilled if considered
of no further value.
Flow net methods of analysis to determine regional or average coefficient
of transmissivity values for highwall deposits, for example, can be used to
verify permeability data obtained by pumping test or core-testing methods.
These tests require the stress of regional cones of pumping depression to
acquire suitable data. Also, predicted drawdown values using various analyt-
ical methods (i.e., electrical analog models and/or digital models) can be
compared with water-level declines actually observed during mining in selected
observation wells. Often these comparisons will demand that adjustments be
made in estimated values of recharge, coefficients of storage, transmissivity,
coefficients of vertical permeability, and other similar hydraulic parameters.
Such water-level observation stations can be fitted with continuous water
level recorders that require servicing only at monthly intervals or that can
be measured on a spot basis at biweekly or monthly intervals using steel
tapes or water level probes. It will prove useful to have such observation
wells located in important aquifers undergoing development and located between
points of water use and the strip mine where mining is planned, in close
proximity to public, industrial, and private surface water and groundwater
supplies.
Other groundwater monitoring points may prove useful at other locations
when establishing the impact that mines are having on groundwater quality in
the down-gradient direction of water flow. The quality of mine water actually
produced during mining and following surface restoration may be compared with
premine forecasts of this quality. Such comparisons will prove useful to
regulatory agencies and mining companies alike. For the latter, claims of
water quality damage caused by mining can be compared with actual water qual-
ity produced within groundwater flow systems adjacent to the mine. Often the
127
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first analysis ever conducted on groundwater supplies is done after a mine
has been put into operation. Any departure in groundwater quality from ideal,
whether natural or man-induced, tends to be blamed on the mine. This problem
is best resolved by sampling wells and springs in advance of mining and over
a long enough period (6 to 12 months) to define seasonal trends adequately.
Knowledge of groundwater flow systems within the vicinity of surface mines
will be required when selecting sites and designing these monitoring wells.
At present, most monitoring tends to be confined to obvious surface discharge
points related to surface mines and largely ignores the groundwater component
of mine discharge that may move laterally or vertically from the mine within
soil water and groundwater flow systems. It should be clear that a single
monitoring well may be adequate for some mines and entirely inadequate under
other circumstances. Monitoring wells should be designed to suit the special
circumstances encountered on a mine-by-mine basis.
Figures 54, 55, and 56 show common situations in which monitoring wells
fail to detect water quality changes resulting from surface mining. The map
view in each figure shows that the direction of groundwater flow is toward
monitoring wells placed to intercept mine drainage. However, the cross-
sectional views show that flow channels containing groundwater influenced by
mining either escape above or below the open end (water-producing part) of
the well and hence remain undetected. A simple flow system is shown in each
case above, when in actual effect, the stratigraphic sequences for coal mea-
sures are far more complicated and will cause complex refractions of flow-
lines as they travel from beds with one hydraulic conductivity to the next.
A single highly conductive or poorly conductive bed only a few meters (or
feet) thick can cause an abrupt alteration in the direction of groundwater
flow. As a general rule, the position of the mine within a groundwater flow
system should be approximately understood—that is, a recharge area, discharge
area, or region where groundwater flow is essentially horizontal. Also, sur-
face mines can alter this flow system, as explained in an earlier chapter.
These factors should be considered when planning monitoring systems.
Zones of fracture concentrations must also be considered when selecting
monitoring well sites completed in bed rock. The more permeable channelways
in rock can cause polluted water to bypass monitoring wells (Figure 56),
concentrate along zones of fracture concentration, and travel through the rock
at a higher velocity when compared to mine water flow in adjacent, less
permeable strata. Mine drainage will follow irregular channel ways in the
general direction of the regional groundwater flow, but it will follow zones
of fracture concentration diagonal to the regional flow pattern.
SOIL WATER
Monitoring of soil water quality poses more difficulty than groundwater.
Soil water is in a state of tension and will not migrate into open boreholes
under the influence of gravity. Benefits of mine restoration using sewage
and sludge applications, limestone aggregates, etc. can be determined by
monitoring shallow groundwater within wells, piezometers, springs and seeps,
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Monitoring Wells
Map View
(b)
Figure 54. Monitoring well placed above groundwater flow channels con-
taining mine drainage. Note that flow lines are refracted by
changes in rock permeability. In the map view, monitoring wells
would appear to be properly located to intercept mine drainage
contained in flow channels. (Modified from Parizek, 1973).
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Monitoring Wells
Map View
Figure 55. Monitoring wells placed below groundwater flow channels
containing mine drainage. In the map view, monitoring
wells would appear to be properly located. (Modified
from R. R. Parizek, 1973).
130
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Direction of
Regional Ground
Map Views
(b)
V Fracture-
Zones
Monitoring
Wells
Direction of
Regional Ground- ,
Water Flow
-Water Supply Well
or Spring
Figure 56. Fracture zones causing mine drainage to bypass monitoring
wells. (Modified from R. R. Parizek, 1973).
131
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mine discharge locations, etc. Soil water monitoring may be desirable at
shallow depths in unsaturated soil and rock to determine early changes in
soil water quality resulting from a particular land treatment practice.
Pressure-vacuum lysimeters (suction lysimeters) appear to be best adapted
for obtaining soil water samples of reasonable size (Figure 57). The bene-
fits and limitations of suction and pan lysimeters are given by Parizek and
Lane (1970), along with suggestions for their installation. These devices
can extract water under a state of tension, provided that there is (1) a
hydraulic connection between capillary-sized openings in the unglazed
porcelain tip of the device, and (2) soil backfilled around the point and
soil or rock. The devices should be located within or below the soil water
column to be sampled, because gravitation water will be derived from infil-
tration of surface water above the sample station in most cases. Lateral
flow of soil water will occur under some field settings, which can result in
the bypassing of soil water above or below a lysimeter. Nested or stacked
lysimeters (3 to 4 per borehole) will reduce the chance of bypassing and
allow for water quality change determination with depth or distance of travel.
Pressure-vacuum lysimeters will provide water samples even when submerged
within groundwater and no matter how coarse-textured the mine spoil. This
will not be true for unsaturated spoil deposits, which require the presence
of fine, capillary-sized pores immediately in contact with the porous porce-
lain tip of the sampler.
LONG-TERM CHANGES IN PRECIPITATION
Some adjustments in hydrologic budget values will be required when
planning surface mines adjacent to existing and proposed power generating
plants that rely on evaporative cooling to dissipate waste heat. Large-scale
"energy parks" of the future that may contain mine mouth coal-fired plants
together with nuclear-powered generating plants can place a significant
daily consumptive draft on local and regional water resources.
The delays and costs of clearing four or five smaller power plants
through environmental review procedures might prove greater than the time and
money spent to win approval for a single 20,000-megawatt plant. C. Hosier
(personal communication, 1976) indicates that the waste heat dissipation
might approach the 40,000-megawatt range for such large-scale energy parks.
This could require a 14,158-1/sec (500-cfs) made-up-demand for cooling water
dissipated to the atmosphere. Such a 45.5-billion I/day (10-billion gallon/
day) consumptive demand can be made up using larger rivers and the Great
Lakes of the more humid eastern United States.
Hosier points out that waste heat in this amount will produce convective
patterns that will have important effects on downwind weather conditions.
Precipitation increases of approximately 127 mm (5 in ) would be possible 32
to 40 km (20 to 25 miles) downwind, especially during the summer months!
This together with increased cloud cover, fog, etc. will suppress evapotrans-
piration, increase infiltration, groundwater recharge, and surface runoff.
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To
Vacuum
Pump
Flask
Rubber
Stopper"
Plastic
Pipe
1.9'O.D.
Any Length
Porous
Ceramic
Cup
Capillary Tube
Rubber Tubing
Clomp
-Copper Tubing
(a)
Plastic Tube
and Clomp
(b)
Super-Sil
Porous Cup -=r
6" Hole-
Bentomfe-
Discharge
Tube
Sample
Bottle
Figure 57. Pressure-vacuum lysimeters used to obtain water within the
zone of aeration above the water table. (Source:
Parizek and Lane, 1970).
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A 102- to 152-mm (4- to 6-in ) annual increase in precipitation would greatly
increase the volume of mine drainage produced at active and abandoned coal
mines during both the growing and nongrowing seasons.
Elevated plumes 1,524 to 2,134 m (5,000 to 7,000 ft) high on cold
mornings could be visible to ground observers 161 km (100 miles) away.
Lightning and ha_il_ _f requencies should increase downwind, and precipitation
should become more mineralized. These and related problems, Hosier indicates,
could be minimized or eliminated by scattering more plants in the 500-megawatt
capacity.
Salts and dissolved mineral matter from cooling water pose other problems
because these will accumulate in the atmosphere and be returned by precipita-
tion. Surface water impacted by acid mine drainage and used for evaporative
cooling would add to this problem. Hosier estimated that fresh river water
might deliver approximately 112 to 336 kb/hectare (100 to 300 Ib/acre) of
salt through precipitation fallout. Sea water used for cooling, by contrast,
might return up to 1.121 kb/hectare (1,000 Ib/acre) of salt near the plant.
Still other longer-term trends in precipitation require attention because
of their impact on mine drainage water quality. Acid precipitation (acid
rainfall) in Scandinavian countries (where this phenomenon is considered a
critical environmental problem) and in the northeastern United States and
southeastern Canada is ascribed to increased combustion of fossil fuels by
man, which relates large quantities of sulfur oxides and nitrogen oxides to
the atmosphere. Harr and Coffey (1975) point out that sulfur dioxide and
hydrogen sulfide are oxidized and hydrolyzed in the atmosphere to sulfuric
acid at varying rates, depending on environmental conditions. Various
nitrogen oxides are likewise transformed into nitric acid. These acids may
be neutralized by alkaline substances also present in the atmosphere, such as
calcite or dolomite dust particles, or they will ultimately fall to the land
and water surfaces with precipitation. Neutralization may occur here, pro-
vided that sources of alkalinity are available within soil water, groundwater,
streams and lakes, soils or rock strata. If these upland watersheds, streams,
and lakes lack a buffering capacity, they in turn will become acidic in
time with various longer-term environmental difficulties.
Of special concern to mine planning is the possible development of acid
and related pollution problems in strip mines that may be induced by acid
rain but are attributed to mining. Pollution abatement measures may thus be
required by the mining industry, when in fact, some costs should be shared by
the segments of society that generate and use energy.
A related problem could develop from the combined effects of mining and
the' decreased pH of precipitation. For example, bacteria have been shown to
be important in catalyzing acid reactions by accelerating the pyrite oxidation
process. Iron-oxidizing bacteria (Thiobacillus ferrooxidans, Ferrobacillus
ferrooxidans) and sulfide-oxidizing bacteria (Thiobacillus thiooxidans) have
been found in great quantities in mine drainage. Singer and Stumm (1970)
state that abiotic oxidation of ferrous iron to ferric iron proceeds very
slowly where pH is less than 4.0; the presence of iron-oxidizing bacteria
accelerates this reaction by a factor greater than 106. Some mine spoils are
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only mildly acid reactive and do not require special water treatment
facilities during and following mining for waters to meet local standards.
But a drop in soil and groundwater pH as a result of acid precipitation com-
bined with pyrite oxidation could bring about a reduction in pH approaching
optimum values for stimulating these bacteria. The rates of future acid
reactions could thus be greatly accelerated. In other words, mine spoils
producing water of favorable or tolerable quality may begin to produce acid
reactions at an accelerating rate in the future, partly for external reasons.
If indeed such a mechanism is possible and current trends in precipita-
tion pH continue, a new dimension of water quality problems may be thrust
on both the mining industry and regulatory agencies.
Recent declines of trout and salmon stocks in streams and lakes of
Sweden, Norway, and Finland have been attributed to inorganic acids derived
from man's activities in northern Europe (Bolin, 1971; Jensen and Snekvik,
1972; Oden and Ahl, 1973).
Similarly, fallout of inorganic acids in rain and snow has been reported
to have severely affected aquatic vegetation and fish populations in numerous
southern Ontario lakes located on the igneous and metamorphic rocks that
make up the Canadian shield (Overrein, 1972; Gorham and Gordon, 1963; and
Beamish, 1974).
Harr and Coffey (1975) summarize the variety of environmental influences
acid rain can have on the environmental setting in the long term. These
changes have been slow in coming and have only recently been accelerated by
man's activities. Impacts can be to limnology and aquatic biology, vegeta-
tion, soil leaching and weathering, forests and soils, biotic components of
soils, and health.
Data on pH of rainfall in the eastern United States appears to be scant
before 1962 (Gambell and Fisher, 1966; Likens and Borman,1974), and the case
for increased acidity of precipitation is not as well documented as for
Scandinavian'countries (Bolin, 1971; Oden, S., 1968; Oden and Ahl, 1973;
Lundholm, 1970; and Reiquam, 1970). However, Cogbell and Likens (1974),
employing chemical data published by others, made predictions of pH values
for the northeastern United States for the periods 1955-56 and 1965-66
(Figures 58 and 59).
The most striking feature their plots reveal is the size of the area in
1955-56 that had a pH of less than 5.6 (Figure 58). In fact, a large region
in the northeast had average pH values below 4.52. These predictions (many
values were not based on actual observations) suggest that acid precipitation
was prevalent over most of the eastern United States by 1955-56. Their
1965-66 predictions (Figure 59) show a similar pattern, but with an increased
land area receiving precipitation having a pH of less than 5.6, including
extensive areas to the northwest and southwest that fall within coalfields
of the Michigan Basin, Illinois Basin, and central Appalachian region. These
and other authors conclude that the exponential increase in consumption of
fossil fuels and mineral deposits since the advent of the industrial
135
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IOO ZOO 3OO
Figure 58. Predicted pH of precipitation over the eastern United States
during the period 1955-56, based on chemical data of Junge
(1958) and Junge and Werby (1958). (From Cogbell and Likens,
1974).
136
-------
5.S3
100 ZOO 3OO
Figure 59. Predicted pH of precipitation over the eastern United States
during the period 1965-66, based on chemical data of Lodge
et al., (1958) and Gambell and Fisher (1966). (From Cogbell
and Likens, 1974).
137
-------
revolution has altered geochemical cycles and modified atmospheric chemistry
in the heavily industrial North Temperate Zone. This trend is bound to
continue.
Precipitation with low pH values may become an important factor in
regions of North America other than in the Shield regions of Ontario and
New York (areas influenced by surface mining, for example). Soils and sur-
face streams and lakes that lack a natural buffer capacity might be expected
to show a steady decline in pH as a result of decreased precipitation pH.
Fortunately, vast regions of North America contain a buffer capacity in
shallow soil, bed rock, surface water, and groundwater. The acid precipi-
tation problem is likely to have its earliest impact where acid spoil is
already causing mine drainage pollution problems. Here, it could accelerate
the rate of acid production and counteract the benefits of mine restoration
attempts.
138
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REFERENCES
Allied Chemical Corporation, Procedure for Determining Alum Dosage, J. Water
and Sewage Works, 122:R-192, 1975.
American Cyanamide Company, Cyanamide Superfloc Flocculants for the Mining
Industry, New York, 22 pp., 1973.
American Public Health Association, Standard Methods for the Examination of
Water and Waste Water, 14th Ed., New York, 1,193 pp., 1975.
Anis, M., Optimum Values for Operational Variables in Turbidity Removal,
J. Water and Sewage Works, 121:66-69, 1974.
1974 Annual Book of ASTM Standards, Part 26, Designation D2797-72: Prepara-
tion of Coal Sample for Microscopic Analysis by Reflected Light,
Designation D2798-72: Microscopic Determination of the Reflectance of
the Organic Components in a Polished Specimen of Coal, ASTM,
Washington, D.C.
Averitt, P., Coal Resources of the United States, January 1, 1974, U.S.
Geological Survey Bulletin 1412, 131 pp., 1974.
Barnes, H. L. and S. B. Romberger, Chemical Aspects of Acid Mine Drainage,
J. Water Pollution Control, 40(3):371-384, 1968.
Beamish, R. J., Loss of Fish Populations from Unexploited Remote Lakes in
Ontario , Canada, as a Consequence of Atmospheric Fallout of Acid,
Water Research (in press), 1974.
Beers, W. F., E. J. Ciolkosz, and L. T. Kardos, Soil as a Medium for the
Renovation of Acid Mine Drainage Water, National Coal Association,
Bituminous Coal Research Inc., Fifth Symp. in Coal Mine Drainage Res.
Reprints, Louisville, Kentucky, pp. 160-171, 1974.
Bhatt, H. B., Analysis of Pollution Control Costs, Contract No. 72-87/RPC-713,
Appalachian Regional Commission, Washington, D.C., 113 pp., 1973a.
Bhatt, H. B., Economics of Coal Mine Drainage Treatment, Proc. of Seminar
on Design of Coal Mine Drainage Treatment Facilities, The Pennsylvania
State University, University Park, Pennsylvania, 113 pp., 1973b.
Biesecker, J. E. and J. R. George, "Stream Quality in Appalachia as Related
to Coal-Mine Drainage, 1965," U.S. Geol. Survey Circular 526, U.S. Gov.
Printing Office, Washington, D.C., 27 pp., 1966.
139
-------
Black, C. A., Ed., Methods of Soil Analysis, Parts 1 and 2, American Society
of Agronomy, Madison, Wisconsin, 1,572 pp., 1965.
Blackshaw, G. L., Pilot Plant Treatment of AMD by Reverse Osmosis Based
Techniques, Fifth Symposium on Coal Mine Drainage Research, NCA/BCR,
Louisville, Kentucky, pp. 312-330, 1974.
Bolin, B., Ed., Air Pollution Across National Boundaries; The Impact on the
Environment of Sulfur in Air and Precipitation, Sweden's Case Study for
the United Nations Conference on the Human Environment, Kungl.
Boktrycheriet, P.A. Norstedt et Soner, Stockholm, Sweden, 96 pp., 1971.
Brady, N. C., The Nature and Properties of Soils, 8th Ed., MacMillan
Publishing Company, New York, 639 pp., 1974.
Braley, S. A., Annual Summary Report of Commonwealth of Pennsylvania Depart-
ment of Health, Industrial Fellowship No. B.3, Mellon Institute,
Pittsburgh, Pennsylvania, 1949.
Braley, S. A., Special Report on the Oxidation of Pyrite Conglomerate: Coal,
Research Project No.370-6, Adivsory Committee on the Ohio River Valley
Water Sanitation Commission, 8 pp., 1960.
Buchanan, R. E. and N. E. Gibbons, Eds., Bergey's Manual of Determinative
Bacteriology, 8th Ed., Williams and Wilkins, Inc., Baltimore, Maryland,
1,246 pp., 1974.
Buckman, H. D., and N. C. Brady, The Nature and Properties of Soil, 7th Ed.,
MacMillan Company, New York, 653 pp., 1972.
Campbell, R. S., 0. T. Lind, G. L. Harp, W. T. Ceiling, and J. E. Letter,
Water Pollution Studies in Acid Strip-Mine Lakes: Changes in Water
Quality and Community Structure Associated with Aging, Symposium on
Acid Mine Drainage Research, Mellon Institute, Pittsburgh, Pennsylvania,
pp. 188-198, 1965.
Caruccio, F. T., An Evaluation of Factors Affecting Acid Mine Drainage
Production and the Groundwater Interactions in Selected Areas of
Western Pennsylvania, Second Symposium on Coal Mine Drainage Research,
Mellon Institute, Pittsburgh, Pennsylvania, pp. 107-151, 1968.
Caruccio, F. T., The Quantification of Reactive Pyrite by Grain Sizes, Third
Symposium on Coal Mine Drainage Research, Mellon Institute, Pittsburgh,
Pennsylvania, pp. 123-131, 1970.
Caruccio, F. T., Trace Element Distribution in Reactive and Inert Pyrite,
Fourth Symposium on Coal Mine Drainage Research, Mellon Institute,
Pittsburgh, Pennsylvania, pp. 48-53, 1972.
Caruccio, F. T., Estimating the Acid Potential of Coal Mine Refuse, The
Ecology of Resource Degradation and Renewal, Blackwell Scientific Pub.,
London, England, pp. 197-205, 1973.
140
-------
Caruccio, F. T. and J. C. Ferris, Paleoenvironment - Prediction of Acid Mine
Drainage Problems, Fifth Symposium on Coal Mine Drainage Research,
NCA/BCR, Louisville, Kentucky, pp. 5-10, 1974.
Caruccio, F. T. and R. R. Parizek, An Evaluation of Factors Influencing Acid
Mine Drainage Production from Various Strata of the Allegheny Group and
the Ground-Water Interactions in Selected Areas of Western Pennsylvania,
SR 65, The Pennsylvania State University, University Park, Pennsylvania,
Coal Research Section, Spec. Research Dept., 213 pp., 1967.
Cavallero, J. A., M. T. Johnston, and A. W. Deurbrouck, Sulfur Reduction
Potential of the Coals of the United States, Report of Investigation
8118, U. S. Bureau of Mines, Washington, D. C., 323 pp., 1976.
Clark, C. W., Oxidation of Coal Mine Pyrites, J. Sanitary Engineering,
92:127-144, 1966.
Coal Mining Effluent Guidelines and Standards, Federal Register, Vol. 42,
No. 80, April 26, 1977, pp. 21380-21390, 1977.
Coal Mining Operating Regulations, Federal Register, Vol. 41, No. 96,
May 17, 1976, pp. 20251-20273, and Vol. 41., No. 94, May 13, 1976,
pp. 19832-19843, 1976.
Coates, D. F. and Y. S. Yu, Pit Slope Manual, Waste Embankments, Canada
Centre for Mineral and Energy Technology, CANMET Report 77-1, Ottawa,
Canada, 137 pp., 1977.
Cogbell, C. V. and G. F. Likens, Acid Precipitation in the Northwestern
United States, Water Resources Research (in press), 1974.
Commonwealth of Pennsylvania Code, PL 1987 (June 1937 as amended), Title 25,
Rules and Regulations Part I., Department of Environmental Resources,
Subpart C, Protection of Natural Resources, Article II Water Resources,
Chapter 93, Water Quality Criteria, pp< 157-194.46, 1937.
Davis, N. S. and R. J. M. DeWiest, Hydrology, John Wiley and Sons, New York,
461 pp., 1966.
Deurbrouck, A. W., Sulfur Reduction Potential of the Coals of the United
States, Report of Investigation 7633, U. S. Bureau of Mines, Washington,
D.C., 289 pp., 1972.
Dupree, W., H. Enzer, S. Miller, and D. Hillier, Energy Perspectives 2.,
U.S. Department of the Interior, Washington, D.C., 244 pp., 1976.
Emrich, G. H., Effects of Coal Mining on Groundwater, SME Fall Meeting,
Rock Mt. Mine Conf., Phoenix, Arixona, AIME-Preprint 65-F-311, 1965.
141
-------
Emrich, G. H., Factors Involved in Estimating Quality and Quantity of Mine
Drainage, Tests for Evaluating the Quality of Mine Drainage
Characteristics of Coal Seams, Mine Drainage Technical Bulletin No. 2.,
Pennsylvania Department of Health, Harrisburg, Pennsylvania, 49 pp.,
1966.
Gambell, A. W. and D. W. Fisher, Chemical Composition of Rainfall in
Eastern North Carolina and Southeastern Virginia, Water Supply Paper
1535-K, U.S. Geological Survey, U. S. Gov. Printing Office, Washington,
D.C., 1966.
Given, P. H., Notes from Short Course on Coal Characteristics and Coal
Conversion Processes, The Pennsylvania State University, University
Park, Pennsylvania, 1974.
Gorham, F. and A. G. Gordon, Some Effects of Smelter Fumes Upon Aquatic
Vegetation near Sudbury, Ontario, Canada, J. Bot., 41:371-378, 1963.
Grim, E. C. and R. D. Hill, Environmental Protection in the Surface Mining of
Coal, EPA-607/2-74-093, U. S. Environmental Protection Agency,
Cincinnati, Ohio, 276 pp., 1974.
Haley, W. A., Changing Methods and Equipment Use in Appalachian Surface Coal
Mining, Second Research and Applied Technology Symposium on Mined-Land
Reclamation, Louisville, Kentucky, pp. 193-203, 1974.
Hall, E. P., The Sheban Project, Symposium on Acid Mine Drainage Research,
Mellon Institute, Pittsburgh, Pennsylvania, pp. 145-160, 1963.
Handbook of Chemistry and Physics, 34th Ed., Chemical Rubber Publishing
Company, New York, 2,950 pp., 1952.
Hanna, G. P., Jr. and R. A. Brandt, Stratigraphic Relations to Acid Water
Production, Unpublished Report, Water Resources Center, The Ohio State
University, Columbus, Ohio, 17 pp., 1971.
Harr, T. E. and P. E. Coffey, Acid Precipitation in New York State, Tech.
Paper No. 43, New York State Department of Environmental Conservation,
Albany, New York, 52 pp., 1975.
Hebley, H. F. and S. A. Braley, Coal Industry Report, Proceedings of 1954
Pennsylvania Clean Streams Conference, Bulletin 146, pp. 20-24, 1955.
Hem, J. D., Complexes of Ferrous Iron with Tannic Acid; Chemistry of Iron
in Natural Water, Water Supply Paper 1459-D, U. S. Geological Survey,
U.S. Gov. Printing Office, Washington, D.C., pp. 75-94, 1960.
Hem, J. D., Study and Interpretation of the Chemical Characteristics of
Natural Water, Water Supply Paper No. 1473, U.S. Geological Survey,
U.S. Gov. Printing Office, Washington, D.C., 363 pp., 1970.
142
"T
-------
Herman, J., A Limestone Barrier Used as a Technique to Neutralize an Acidic
Stream at Snowshoe Summit Lodge, Geological Sciences 319, Independent
Research, Paper Submitted May 23, 1977, to R. R. Parizek, Instructor,
The Pennsylvania State University, University Park, Pennsylvania,
15 pp., 1977.
Hittman Associates, Inc., Erosion and Sediment Control: Surface Mining in the
Eastern United States, Vols. 1 and 2, EPA-625/3-76-006, U.S.
Environmental Protection Agency, Cincinnati, Ohio, 1976.
Hosier, C. L., personal communication, Dean, College of Earth and Mineral
Sciences, The Pennsylvania State University, University Park,
Pennsylvania, 1976.
Jackson, M. L., Soil Chemical Analysis, University of Wisconsin, Madison,
Wisconsin, 495 pp., 1970.
Jensen, K. W. apd E. Snekvik, Low pH Levels Wipe Out Salmon and Trout
Populations in Southernmost Norway, Anbio, 223-225, 1972.
Jones, D. C., J & L Initiates AMD Control with Lime Slurry Pilot Plant,
J. Coal Mining and Processing, 4(7):32-35, 1967.
Junge, C. E., The Distribution of Ammonia and Nitrate in Rainwater Over The
United States, Amer. Geophys. Union Trans., 39:241-248, 1958.
Junge, C. E. and R. T. Werby, The Concentration of Chloride, Sodium,
Potassium, Calcium and Sulfate in Raimrater Over the United States,
J. Meteor., 15:417-425, 1958.
Kalb, W., Application of Soda Ash in the Treatment of Coal Mine Drainage
from Surface Mines, Short Course Notes on Controlling Water Pollution
in Coal Mining, The Pennsylvania State University, University Park,
Pennsylvania, 1975 (Equipment available from: The TraDet Company,
930 Kinnear Road, Columbus, Ohio).
Koppe, E. R., Short Course Notes on Controlling Water Pollution in Coal
Mining, The Pennsylvania State University, University Park, Pennsylvania,
1975.
Krauskopf, K. G., Introduction to Geochemistry, McGraw-Hill, New York, 1967.
Krauskopf, K. G., Geochemistry of Micronutrients In R. D. Dinaver (Ed.),
Micronutrients in Agriculture, Soil Society of America, Madison,
Wisconsin, 1972.
P
Kunin, R., The Use of AMBERLITE Ion .Exchange Resins in Treating Acid Mine
Waters of Philipsburg, Pennsylvania, Fifth Symposium on Coal Mine
Drainage Research, Louisville, Kentucky, NCA/BCR, pp. 302-311, 1974.
143
-------
Lachman, R. and H. L. Lovell, An Investigation of the Natural Beneficiation
of Coal Mine Drainage, Special Report 76, The Pennsylvania State
University to the Commonwealth of Pennsylvania, University Park,
Pennsylvania, 187 pp., 1970.
Likens, G. F. and F. H. Borman, A Serious Acid Rain: Environmental Problem,
Science, V. 184, p. 1176-1179, 1974.
Linke, W. F., Solubilities of Inorganic and Metal Organic Compounds, Vol. 2,
American Chemical Society, Washington, D.C., 1,914 pp., 1965.
Linsley, R. K., Jr., M. A. Kohler and J. L. Paulhus, Hydrology for Engineers,
McGraw-Hill, New York, 482 pp., 1968.
Lodge, J. P., Jr., K. C. Hill, J. B. Pate, E. Lorange, E. Basbergill,
W. Lazrus, and A. L. Swanson, Chemistry of United States Precipitation,
National Center for Atmospheric Research, Boulder, Colorado, 66 pp.,
1968.
Lorenz, W. C. and E. C. Tarpley, Oxidation of Coal Mine Pyrites, Report of
Investigation 6247, U. S. Bureau of Mines, Washington, D.C., 28 pp.,
1963.
Lovell, H. L. and R. D. Reese, A Study of Reactions Between Coal and Coal
Mine Drainage, Special Report 54, The Pennsylvania State University to
the Commonwealth of Pennsylvania, University Park, Pennsylvania,
179 pp., 1965.
Lovell, H. L., M. L. Miskovsky, P. T. Luckie, and T. S. Spicer, Regarding the
Water Pollution Potential from Coal Refuse Piles, Fifth Middle Atlantic
Regional Meeting, American Chemical Society, 15 pp., 1970.
Lovell, H. L., An Appraisal of Neutralization Processes to Treat Coal Mine
Drainage, EPA 670/2-73-093, U. S. Environmental Protection Agency,
Cincinnati, Ohio, 347 pp., 1973.
Lovell, H. L. and J. Gunnett, Hydrogeological Influences in Preventive
Control of Mine Drainage from Deep Coal Mining, Special Report 100, The
Pennsylvania State University to the Commonwealth of Pennsylvania,
University Park, Pennsylvania, 89 pp., 1974.
Lovell, H. L., Coal Preparation Section of Final Report on the U. S.
Department of Commerce, Commerce Technical Advisory Board, Independence
Blueprint, NTIS-COM-75-10500, National Technical Information Service,
Washington, D.C., 70 pp., 1975.
Lundholm, B., Interactions Between Oceans and Terrestrial Ecosystems,
In. S. F. Singer (Ed.), Global Effects of Environmental Pollution,
Springer-Verlag, New York, 1970.
144
-------
Mansfield, S. P., and W. Spackman, Petrographic Composition and Sulfur
Content of Selected Pennsylvania Bituminous Coal Seams, Special Report
50, The Pennsylvania State University to the Commonwealth of
Pennsylvania, University Park, Pennsylvania, 178 pp., 1965.
McCarthy, R. R., Preventing the Sedimentation of Streams in a Pacific
Northwest Coal Surface Mine, First Research and Applied Technology
Symposium on Mined Land Reclamation, NCA/BCR, Pittsburgh, Pennsylvania,
pp. 277-286, 1973.
Morrow, J. J. and E. G. Rausch, Colloid Destabilization with Cationic
Polyelectrolytes as Affected by Velocity Gradients, J. American Water
Works Association, 66:646-653, 1974.
National Coal Association, First Symposium on Mine and Preparation Plant
Refuse Disposal, NCA/BCR, Louisville, Kentucky, 275 pp., 1974.
National Water Commission, Water Rights for the Appalachian Region, R. L.
Dewanup and D. Jensen, Eds., A Summary Digest of State Water Laws,
Washington, D.C., 1973.
Newhouse, W. H., Some Forms of Iron Sulfide Occurring in Coal and Other
Sedimentary Rocks, J. Geology, 35(1):75-83, 1927.
Oden, S., The Acidification of Air and Precipitation and Its Consequences
on the Natural Environment, Bull. No. 1-1, Tr-1177, S. W. National
S. A. Res. Council, Ecology Committee, Translation Consultants Limited,
Arlington, Virginia, p. 86, 1968.
Oden, S. and T. Ahl, The Acidification of Scandivanian Waters, Transla. Ser.
No. 2535, Fish Res. Board, F. W. Inst., Winnipeg, Manitoba, Canada,
33 pp., 1973.
Overrein, L. N., Sulfur Pollution Patterns: Observed Leaching of Calcium
in Forest Soil Determined, Ambio., pp. 145-147, 1972.
Parizek, R. R., "Prevention of Coal Mine Drainage Formation by Well
Dewatering," College of Earth and Mineral Sciences, Experiment Station,
Special Research Report SR-82, The Pennsylvania State University,
University Park, Pennsylvania, 1971.
Parizek, R. R., Cause of Acid Mine Drainage in Jonathan Run, Centre County,
Pennsylvania, Report to Miller Kistler Lee and Campbell, Attorneys,
State College, Pennsylvania, 1971.
Parizek, R. R., Site Selection Criteria for Wastewater Disposal - Soils and
Hydrogeologic Considerations, pp. 95-147, In: W. E. Sopper and
L. T. Kardos, Eds., Recycling Treated Municipal Wastewater and Sludge
Through Forest and Cropland, The Pennsylvania State University Press,
University Park, Pennsylvania, 479 pp., 1973.
145
-------
Parizek, R. R., Connector Well Coal Mine Drainage Pollution Abatement
Demonstration, Service Contract EER-BO-A, Connector Well Demonstration
Project, U. S. Environmental Protection Agency, and Pennsylvania
Department of Environmental Resources, Harrisburg, Pennsylvania, 1974.
Parizek, R. R. and B. E. Lane, Soil-Water Sampling Using Pan and Deep
Pressure-Vacuum Lysimeters, Hydrology, 11:1-21, 1970.
Parizek, R. R. and E. Tarr, Mine Drainage Pollution Prevention and Abatement
Using Hydrogeological and Geochemical Systems, Fourth Symp. on Coal Mine
Drainage Research, Mellon Institute, NCA/BCR, Pittsburgh, Pennsylvania,
1972.
Pearson, F. H. and A. J. MacDonald, Neutralization of Acidic Waters by
Crushed Limestone, The Pennsylvania State University, University Park,
Pennsylvania, Publ. No. 79, Inst. for Res. on Land and Water Res.,
157 pp., 1974.
Pearson, F. H. and A. J. McDonald, Limestone Barriers to Neutralize Acidic
Streams, Use of Crushed Limestone to Neutralize Acid Waters, J. Env.
Eng. Division, lOl(EIE)-.139-158,1975.
Rao, C. P. and H. I. Gluskoter, Occurrence and Distribution of Minerals
in Illinois Coals, Illinois Geological Survey Circular 476, Urbana,
Illinois, 56 pp., 1973.
Reiquam, H., European Interest in Acidic Precipitation, pp. 289-292, In:
R. J. Englemann and W. G. N. Slinn (Eds.), Precipitation Scavenging,
Symposium Series 22, U.S. Atmoic Energy Commission, Oak Ridge,
Tennessee, 1970.
Riley, C. V., Limnology of Acid Mine Water Impoundments, Proceedings of
Symposium on Acid Mine Drainage Research, Mellon Institute, Pittsburgh,
Pennsylvania, pp. 175-167, 1965.
Robertson, C. E. and J. D. Hem, Solubility of Aluminum in the Presence of
Hydroxide, Fluoride, and Sulfate, Water-Supply Paper 1827-C, U.S.
Gov. Printing Office, Washington, D.C., 37 pp., 1969.
Ruch, R. R., J. J. Gluskoter, and N. F. Shimp, Occurrence and Distribution
of Potentially Volatile Trace Elements in Coal, Environmental Geology
Note No. 61, Illinois Geological Survey, Urbana, Illinois, 43 pp.,
1973.
Schdffer, R. B., The National Pollutant Discharge Elimination System and the
Coal Industry, Proceedings of Third Symposium on Surface Mining and
Reclamation, NCA/BCR, Louisville, Kentucky, pp. 2-6, 1975.
Schicht, R. J. and W. C. Walton, "Hydraulic Budget for Three Small Watersheds
in Illinois," Illinois State Water Survey Report, Report of Investiga-
tion 40, 1961.
146
-------
Schneider, W. J., Water Data for Metropolitan Areas, Water Supply Paper
1871, U.S. Geological Survey, U.S. Gov. Printing Office, Washington,
D.C., 397 pp., 1968.
Silverman, M. P., Mechanism of Bacterial Pyrite Oxidation, J. Bacteriol.,
94(4):1046-1051, 1967.
Singer, P.C. and W. Stumm, Acidic Mine Drainage: The Rate-Determining
Steps, Science, 167:1121-1123, 1970.
Skelly and Loy, Inc., Processes, Procedures and Methods to Control Pollution
from Mining Activities, EPA 430 9-93-011, U.S. Environmental Protection
Agency, Cincinnati, Ohio, 59 pp., 1973.
Skelly and Loy, Inc., Economic Engineering Analysis of the U.S. Surface
Coal Mines and Effective Land Reclamation, USBM Contract Report
S0241049, U.S. Department of the Interior, Washington, D.C., 580 pp.,
1975.
Smith, E. E., and K. S. Shumate, Sulfide to Sulfate Reaction-Mechanisms,
EPA-14010, FPS 02/70, U.S. Environmental Protection Agency, Cincinnati,
Ohio, 115 pp., 1970.
Smith, R. M., W. E. Grube, T. Arkle, and A. Sobek, Mine Spoil Potentials
for Soil and Water Ouality, EPA-670/2-74-070, U.S. Environmental
Protection Agency, Cincinnati, Ohio, 319 pp., 1974.
Sopper, W. E., J. A. Dickerson, C. F. Hunt, and L. T. Kardos, Revegetation of
Strip Mine Spoil Banks Through Irrigation With Municipal Sewage Effluent
and Sludge, Reprint Series No. 20, Institute for Research in Land and
Water Resources, The Pennsylvania State University, University Park,
Pennsylvania, pp. 6-11, 1970.
Taylor, S. A. and G. L. Ashcroft, Physical Edaphology, W. H. Freeman and
Company, San Francisco, California, 533 pp., 1972.
Terzaghi, K., and R. B. Peck, Soil Mechanics and Engineering Practice,
John Wiley and Sons, New York, 1967.
Thomas, H. E. , "Water Rights in Areas of Ground Water Mining," Geological
Survey Circular 347, U.S.D.I., Washington, D.C., 1955.
Thornbury, W. D., Principles of Geomorphology, 2nd Ed., John Wiley & Sons,
Inc., New York, 594 pp., 1969.
Tisdale, S. L. and W. L. Nelson, Soil Fertility and Fertilizers, MacMillan
Publishing Company, New York, 694 pp., 1975.
Tolsman, J. and A. N. Johnson, Uniroyal Inc., The Use of Latex as A Soil
Sealant to Control AMD, EPA 14010 EFK 06/72, U.S. Environmental
Protection Agency, Cincinnati, Ohio, 347 pp., 1973.
147
-------
U.S. Bureau of Mines, Strippable Reserves of Bituminous Coal and Lignite in
the United States, U.S. Bureau of Mines Information Circular 8531, U.S.
Department of the Interior, Washington, D.C., 148 pp., 1971.
U.S. Bureau of Mines, Demonstrated Coal Reserve Basis of the United States
on January 1, 1974, Mineral Industries Surveys, Coal - Bituminous and
Lignite, Annual, 66 pp., 1976.
U.S. Department of Commerce, National Oceanic and Atmospheric Administration,
National Weather Service, Climatological Reports.
U.S. Department of Commerce, National Oceanic and Atmospheric Administration,
National Weather Service, Daily Snypotic Weather Maps.
U.S. Environmental Protection Agency, Coagulant Aids for Water Treatment,
American Water Works Assn., 65:663-664, 1973.
U.S. Environmental Protection Agency, An Approach to State and Areawide 208
Planning for Control of Current and Abandoned Nonpoint Sources of Water
Pollution, Draft Report, 104 pp., 1976.
Waddell, R. K., Evaluation of a Surficial Application of Limestone and Flue
Dust in the Abatement of Acidic Drainage: Jonathan Run Drainage Basin
at Interstate 80, Centre County, Pennsylvania, Unpublished Ph.D.
Dissertation, Dept. of Ecosciences, The Pennsylvania State University,
University Park, Pennsylvania, 301 pp., 1978.
Waddell, R. K., Jr., R. R. Parizek, and D. R. Buss, Surficial Application of
Limestone and Lime Plant Flue Dust in the Abatement of Acidic Drainage:
Jonathan Run Drainage Basin at Interstate 80, Centre County, Pennsyl-
vania, Final Report, Federal Highway Administration and Pennsylvania
Department of Transportation, Harrisburg,Pennsylvania and Baltimore,
Maryland, 1979.
Walker, F. E. and F. E. Hartner, Forms of Sulfur in U.S. Coals, U.S. Bureau
of Mines Information Circular 8301, U. S. Department of the Interior,
Washington, D.C., 51 pp., 1966.
Wedephal, K. H., Geochemistry, Holt, Rhinehart, and Winston, New York,
231 pp., 1971.
Whitemore, D. 0., The Chemistry and Mineralogy of Ferric Oxyhydroxide
Precipitated in Sulfate Solutions, Ph.D. Thesis, The Pennsylvania State
University, University Park, Pennsylvania, 159 pp., 1973.
Williams, E. G. , Marine and Fresh Water Fossilferous Beds in the Pottsville
and Allegheny Groups of Western Pennsylvania, J. Paleontology,
34(5):908-922, 1960.
Williams, E. G. and M. L. Keith, Relationship Between Sulfur in Coals and the
Occurrence of Marine Reef Beds, Economic Geology, 58:720-729, 1963.
148
-------
Wilmoth, R. D. and J. L. Kennedy, Combination Limestone-Lime Treatment on Acid
Mine Drainage, Proceedings of Seventh Symposium on Coal Mine Drainage
Research, NCA/BCR, Louisville, Kentucky, 37 pp., 1976.
Winkler, E. M. and P. C. Singer, Crystalline Pressure on Salts in Stone and
Concrete, Bull. Geol. Soc. Amer. 83(11):3509-3513, 1972.
Wright, C. C. and H. Bauman, Pollution of Rivers and Streams in Pennsylvania,
Report 13, Mineral Industries Experiment Station (Now College of Earth
and Mineral Sciences), University Park, Pennsylvania, M-25-B-III(A),
125 pp., 1943.
149
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GLOSSARY
Acidic overburden - strata overlying a coal seam that, when contacted by
water, has the potential for making it acidic.
Alkaline overburden - strata overlying a coal seam that, when contacted by
water, has the potential for making it alkaline.
Aquifer - a stratum or zone below the surface of the earth capable of
storing, transporting, or producing water, as from a well.
Attrition - an autogeneous process that maintains surfaces of solids clean
and free of foreign substances, such as reaction products. It results
from frictional action upon contact of two particles.
Autotrophic - needing only inorganic compounds for nutrition.
Basicity - the available alkalinity in a material that may be used in a
neutralization process.
Biochemical oxidation - a process in which substances such as pyrite and
ferrous sulfate are oxidized to a higher oxidation state by some
mechanism in which the metabolic life process predominates.
Calcined - subjected to very high temperatures that change the composition of
a material (such as calcined lime, which is prepared by the heating of
limestone and the subsequent removal of carbon dioxide).
Cation exchange reaction - the replacement of undesirable cation or anion
components in coal mine drainage by more acceptable soluble ions by
solubility principles.
Coal mine drainage (CMP) - water transferred from a coal mine environment.
Such waters usually have enhanced dissolved solids and poor quality.
Effluent - a liquid, solid, or gaseous product or waste leaving a treatment
process or system.
Feed or raw water - water entering a treatment process or system. This term
is usually applied to those waters entering the first stage of a
treatment system.
Flocculant - a surfactant reagent that enhances the agglomeration of very
fine particles to settleable floes.
150
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Heterotrophic - obtaining nourishment primarily from organic matter.
Influent - a material stream (liquid, solid, or gaseous) entering a treatment
process.
Leaching - a solution process whereby the desired metal is recovered directly
from the ore. Leaching can occur in situ or in specially prepared dumps.
Lineament - significant lines of landscapes that reveal the hidden archi-
tecture of the rock basement. Such areas typically have greater water
permeability than the adjacent terrain.
Lixiviant - a solution enhancing the solubility of certain or all components
of a material.
Mineralized waters - waters that contain soluble mineral substances acquired
by the water when passing through strata of the earth.
Neutralization - a chemical reaction or process that decreases the hydrogen
ion content of coal mine drainage.
Neutralization equivalent - the quantity of chemical needed to react com-
pletely and without excess in a neutralization reaction. The quantity
is consistent with that defined stoichiometrically by a balanced
chemical equation.
Phytogenetic - of plant origin.
Polluted water - waters containing substances that are inimical to normal
utilization and that are not indigenous to most waters. The term used
is not restricted to biological contamination.
Reactivity - the extent of response, usually chemical, between two or more
materials.
Settleability - an arbitrary concept for the behavior of solids in a fluid
which seeks to describe a variety of settling characteristics.
Slaking - a hydration process that converts calcined lime to hydrated lime.
Sludge - a thick, aqueous suspension of sparingly soluble materials that
are usually (but not necessarily) composed of valueless waste substances.
Slurry - a dilute aqueous suspension of a sparingly insoluble material.
Toxic material - material in the overburden that contributes poisonous
components to the environment.
Yellowboy process - a conventional method of treating coal mine drainage by
the addition of hydrated lime, followed by oxidation of ferrous iron
by air and the separation of insoluble impurities by sedimentation.
151 ir US GOVERNMENT PRINTING OFFICE 1981-757-064/0304
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