PA-670/2-74-009
:ebruary 1974
Environmental Protection Technology Series
Analysis of Pollution Control Costs
Office of Research and
U.S. Environmental Protectio
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
1. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology to repair or prevent environmental
degradation from point and non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval does
not signify that the contents necessarily reflect the views
and policies of the Environmental Protection Agency, nor does
mention of trade names or commercial products constitute
endorsement or recommendation for use.
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EPA-670/2-7^-009
February
ANALYSIS OP POLLUTION CONTROL COSTS
By
Frank • J. Doyle
Harasiddhiprasad G. Bhatt and
John R. Rapp
ARC Contract No. 72-87/RPC-713
Project lUOlO HQ.C
Program Element IBBO^O
Project Coordinator
Dr. David R. Maneval
Appalachian Regional Commission
1666 Connecticut Avenue
Washington, D.C. 20235
Prepared for
APPALACHIAN REGIONAL COMMISSION
WASHINGTON, D.C. 20235
and
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. EjmROIMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 2C&60
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 • Price $3.20
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ABSTRACT
This report fulfills requirements for an effective, workable handbook on
pollution control costs and factors effecting these costs for the Monon-
gahela River Basin. The information in the report is based on the latest
technological developments and cost analyses of recent reclamation projects.
Although the report was developed for the Mbnongahela River Basin study,
the cost estimates and supporting data should prove useful for all of
Appalachia and other areas with similar topography, mine drainage pollution
problems and mining history.
Specific areas covered by the report are surface mines, refuse piles, mine
sealing, mine drainage treatment, air pollution control, solid waste hand-
ling and disposal, abandoned automobiles, and erosion and sedimentation
control.
This report was submitted in partial fulfillment of Project number lUoiO HQC
under Appalachian Regional Commission Contract Number 72-87/RPC-713 by
Michael Baker, Jr., Inc., Beaver, Pennsylvania 15009, under the cooperative
sponsorship of the Appalachian Regional Commission and the U.S. Environmental
Protection Agency. Work was completed as of February 1973-
ii
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CONTENTS
Abstract
Executive Summary
Introduction
Part A - Abatement of Coal Mine Drainage Pollution and Mining
Related Problems
I Strip Mine and Refuse Bank Backfilling and Grading
II Revegetation of Lands Disturbed by Coal Mining
III Mine Sealing
IV Stream Diverson
V Treatment of Mine Drainage
VI Other Mine Drainage Abatement Procedures
VII Refuse Bank and Mine Fires
VIII Mine Subsidence Control
Part B - Abatement of Pollution from Sources Other Than
Coal Mining
I Cost Estimate for Air Pollution Control Equipment
II Solid Waste Handling and Disposal Costs
III Abandoned Automobile Removal Costs
IV Erosion and Sedimentation Control Costs
V Industrial Wastes "Orphan" and Other Environmental
Problems in the Public Sector
Addendum
Acknowledgment s
Page
ii
V
1
13
43
57
109
115
319
329
345
359
385
401
409
419
427
437
iii
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EXECUTIVE SUMMARY
At the Monongahela Enforcement Conference convened in Pittsburgh,
Pennsylvania in August, 1971, the Appalachian Regional Commission was
charged with the task of developing a comprehensive environmental improve-
ment program for the Monongahela River Basin. As part of this responsibil-
ity, the Commission must determine as accurately as possible the costs of
various remedial programs which it recommends. An effective, workable
handbook on pollution control costs and factors effecting these costs based on
the latest technological developments and cost analyses of recent reclamation
projects is needed to perform this function.
This study performed by Michael Baker, Jr. , Inc. under ARC Con-
tract No. 72-87/RPC-713 titled "Analysis of Pollution Control Costs" provides
the data which will enable the Appalachian Regional Commission to estimate
costs of pollution abatement in the Monongahela River Basin. Although this
publication was developed for the Monongahela River Basin study, the cost
estimates and supporting data should prove useful for all of Appalachia and
other areas with similar topography, mine drainage pollution problems and
mining history. The unit price cost estimates are based on the best available
information and are suitable for budget estimates and preliminary planning,
but they do not replace the detailed cost estimate required in producing con-
tract plans and specifications.
The subject matter is separated into two parts. Part A, Abatement
of Coal Mine Drainage Pollution and Mining Related Problems, contains:
1. Strip Mine and Refuse Bank Backfilling and Grading, 2. Revegetation of
Lands Disturbed by Coal Mining, 3. Mine Sealing, 4. Stream Diversion,
5. Treatment of Mine Drainage, 6. Other Mine Drainage Abatement Proced-
ures, 7. Refuse Bank and Mine Fires and 8. Mine Subsidence Control. Part
B, Abatement of Pollution from Sources Other Than Coal Mining, contains:
1. Cost Estimates for Air Pollution Control Equipment, 2. Solid Waste Hand-
ling and Disposal Costs, 3. Abandoned Automobile Removal Costs, 4. Erosion
and Sedimentation Control Costs and 5. Industrial Wastes "Orphan" and Other
Environmental Problems in the Public Sector. An "Addendum" reports on recent
publications noted after completion of the main body of the report. The report
contains about 275 references to important publications on pollution abatement
and nearly 200 tables and text figures.
Unit Costs for Mine Drainage Abatement
Significant unit costs for mine drainage abatement recommended for
use in remedial program planning for the Monongahela River Basin are:
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Surface Mine and Refuse Bank Reclamation
1. Strip Mine Backfilling and Grading
2. Refuse Bank Contouring and Grading
3. Soil Cover for Graded Refuse Bank
4. Refuse Bank Removal and Burial
5. Soil Cover at Burial Site
6. Clearing and Grubbing
7. Re vegetation
Mine Sealing
$l,250/Acre
$l,000/Acre
$2,500/Acre
$ 1.00/C. Y.
$ 0.50/Yd.2
$ 300/Acre
$350 to $ 400/Acre
3.
4.
5.
6.
7.
Hydraulic Seals for Accessible Mines
a) Halliburton Type Seals (Chemical grout
and aggregates including remedial grout-
ing, but no grout curtain)
b) Reinforced Concrete Seal including
100 L.F. of grout curtain $15,000
Hydraulic Seals for Inaccessible Mines
a) Grouted Double Bulkhead Seal
including 100 L.F. of grout curtain
b) Grouted Single Bulkhead Seal including
100 L. F. of grout curtain
Limestone Barrier Mine Seal (Permeable Plug)
Air Seal (Masonry)
Dry Seal (Clay)
Dry Seal (Masonry)
Grout Curtain $40
$10,000/Each
to $20, 000/Each
$21, 000/Each
$ 5, 000/Each
$ 7, 500/Each
$ 5, 000/Each
$ 1, 500/Each
$ 3, 500/Each
to $ 80/L. F.
Stream Diversion
Treatment of Mine Drainage
$
20/L.F.
The design of mine drainage treatment plants is in its infancy. The
capital and operating costs of existing treatment plants may not be an indica-
tion of future treatment costs because most of the actual cost data developed
to date is based on lime neutralization. A great deal of effort has been ex-
pended in the last few years by government agencies and industry in develop-
ing processes for treatment of mine drainage other than lime neutralization
which has several disadvantages including the production of large volumes of
sludge and the addition of hardness to the effluent. The mine drainage treat-
ment processes which show promise are: 1) limestone neutralization, 2) com-
bination lime-limestone neutralization, 3) ion exchange, 4) biochemical oxi-
dation followed by limestone neutralization, and 5) reverse osmosis. Several
treatment plants are now in operation using the first four processes. A re-
duction in capital and operating costs should occur as progress is made in
design and methods of operation.
VI
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It is difficult to recommend capital and operating cost formulas for use
in developing overall cost estimates for mine drainage treatment in the Mon-
ongahela River Basin. It is necessary to not only predict inflationary trends,
but also the effect a technological development or breakthrough would have on
costs. Based on the mine drainage treatment data in this report, Gibbs & Hill,
Inc. proposed using the following capital cost formula and operating cost in
their study for the Appalachian Regional Commission:
Installed Capital Cost $ = 350, 000 Q°- 72
Where Q is flow expressed in MGD
Operating Cost 20£/1,000 gallons treated
The capital cost is developed from U. S. Bureau of Mines cost curves
for limestone treatment plants, whereas, operating cost is based on using hy-
drated lime as a neutralizing agent.
Unit Costs for Mining Related Problems^
Extinguishment of Coal Refuse Bank Fires
The following formula based on project costs tabulated in this report,
where refuse was sluiced into a lagoon using a water cannon, is being used by
Gibbs & Hill, Inc. in their study for the Appalachian Regional Commission:
$ = 1.1 V Where V is volume in million cu. yds.
Mine Subsidence Control
Fly Ash Injection Methods $75, 000/Acre
Grouted Aggregate Pier Method $85, 000/Acre
The report contains the results of an extensive study of pollution con-
trol project cost data. A thorough search was made of the literature, and it
is believed most of the significant recent publications were reviewed. Signifi-
cant pollution control cost figures in older publications were updated using the
Engineering News-Record Cost Index. Comparisons were made of the estimated
costs of construction with actual "as built" project costs and factors causing
errors have been identified. Meetings were held with many individuals in gov-
ernment and industry and their cooperation in supplying unpublished information
used in this study is gratefully acknowledged.
VII
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INTRODUCTION
TABLE OF CONTENTS
Page No.
Purpose and Scope of Report 3
Format of Report 5
Monongahela River Basin Pollution Studies 5
References 8
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INTRODUCTION
Purpose and Scope of Report
In 1971, the Environmental Protection Agency reconvened in Pittsburgh,
Pennsylvania an interstate water pollution control conference on the Monongahela
River Basin( 1 > 2). The purpose of the conference was to adopt new standards at
both the state and federal levels to curb mine drainage pollution, to recommend
a mine drainage abatement program and to discuss the results of studies on mine
drainage pollution within the basin completed since the first conference was held
in 1963(3>4'5).
The conferees, consisting of representatives from the states of West
Virginia, Pennsylvania and Maryland, the Ohio River Valley Water Sanitation
Commission (ORSANCO) and the Federal Government, recognizing that aband-
oned mine drainage pollution in the Monongahela River Basin is primarily a
regional problem, requested the Appalachian Regional Commission to direct
and coordinate with the Environmental Protection Agency and other appropriate
agencies the abatement program recommended by the state and interstate con-
The Appalachian Regional Commission is charged with the task of devel-
oping a comprehensive environmental improvement program for the Monongahela
River Basin. As part of this responsibility, the Commission must determine as
accurately as possible the costs of various remedial programs which it recom-
mends. An effective, workable handbook on pollution control costs and factors
effecting these costs is needed to perform this function. The Appalachian Reg-
ional Commission engaged Michael Baker, Jr. , Inc. to perform the pollution
control cost study under ARC Contract No. 72-87/RPC -713 titled "Analysis of
Pollution Control Costs. "
This report provides data which will enable the Appalachian Regional
Commission to estimate costs of abating mine drainage and other environmental
problems in the Monongahela River Basin. In order to produce an effective,
workable handbook, it is necessary to accumulate and analyze available project
cost data on pollution control on a region-wide basis and translate it into a form
from which projections for costs of future work can be estimated. For this
assignment, Michael Baker, Jr., Inc. was required to perform the following
tasks:
1. Collect, become familiar with, analyze and evaluate currently available
literature on costs of mine drainage pollution abatement. Existing publi-
cations^, 8) on mine drainage pollution control costs were developed using
data prior to 1966, but more effective work has been accomplished in this
field since 1966 than in all the previous years.
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2. At meetings with State, Federal and private individuals or through other
analysis gather relevant data and then analyze recent (since 1966) mining
area restoration projects in Appalachia to determine the costs of recla-
mation.
3. Compare the estimated costs of construction with actual "as built" project
costs to furnish initial insight into the problem of accurately projecting
construction costs.
4. Identify factors causing errors in cost estimates.
5. Using appropriate factors, update pollution control cost figures in the lit-
erature prior to 1970 where updating would be reliable and of current use-
f ulne s s .
6. Prepare a handbook setting forth unit costs for abatement of coal mine
drainage pollution and mining related problems. The handbook should in-
clude figures for the latest technological developments or processes in-
cluding those utilized immediately prior to the reporting.
7. Prepare analyses of presently available abatement techniques and determine
average unit costs for abatement of pollution from sources other than coal
mining. This part of the project merely asked for the best estimates of
costs from the best data presently available for the following environmental
deterrent categories: a) air pollution, b) solid wastes, c) abandoned auto-
mobiles, d) erosion and sedimentation, and e) industrial wastes "orphan"
and other environmental problems in the public sector.
Although this publication is concerned mainly with an analysis of pollution
control costs applicable for use in developing a comprehensive environmental im-
provement program for the Monongahela River Basin, the cost estimates and sup-
porting data should prove useful for all of Appalachia and other areas with similar
topography, mine drainage pollution problems and mining history. Emphasis was
placed on reclamation project cost data from areas within or adjacent to the Mon-
ongahela River Basin. But since Pennsylvania, followed by Vest Virginia, are
the leaders in mine drainage pollution abatement, the project cost data from these
states would include most of the significant data on mine drainage abatement in
the United States. Maryland, Ohio, Kentucky and Tennessee have recently passed
stringent mining regulations and have active mine drainage abatement programs,
but there is only a limited amount of information available from these states at
present.
The unit price cost estimates in this publication are based on the best
available information and are suitable for budget estimates and preliminary plan-
ning, but are not intended to replace the need for a detailed cost estimate re-
quired in producing contract plans and specifications.
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Format of Report
The report has been divided into two main categories, "Abatement of
Coal Mine Drainage Pollution and Mining Related Problems" and "Abatement
of Pollution From Sources Other Than Coal Mining. " Each category contains
sections dealing with individual environmental problems within that category.
For convenience and easy reference, there is a general "Table of Contents"
at the beginning of the report and each section has a detailed "Table of Con-
tents" which lists tables and figures found in the section. An "Addendum"
was necessary to report on recent publications noted after completion of the
appropriate section.
Monongahela River Basin Pollution Studies
The Monongahela River Basin overlies one of the most valuable and ex-
tensively developed deposits of bituminous coal in the world. Coal mining,
coking and iron and steel manufacturing have made this district world famous(°).
The basin lies entirely in the Appalachian Plateau Province and is characterized
by rugged topography with narrow stream valleys. The drainage basin comprises
a total of 7, 340 square miles of which 57 percent is in West Virginia, 38 percent
in Pennsylvania and 5 percent in Maryland. Stream flow in the basin is regulated
to some extent by a network of multiple purpose dams and reservoirs in the head-
waters. The lower Monongahela River passes through one of the most densely
developed industrial areas in the nation.
The mine drainage inventory completed by the Environmental Protection
Agency(l»2) documented the belief that the Monongahela River Basin is more
intensely polluted by mine drainage than any other major drainage basin in the
United States. The total net acid load from all coal mining sites was over one
million pounds per day and the iron load more than 300, 000 pounds per day.
This data did not reflect the additional pollution of other chemicals or sediment
which are found in mine drainage as a result of industrial and urban develop-
ment, timbering, farming and other activities within the basin. Less than 18
percent depletion of the original bituminous coal resources has resulted in this
vast mine drainage pollution problem.
If we assume that drainage from combination underground-surface mines
originates primarily from underground sites, the inactive underground mines
would be responsible for about 55 percent of the net acid load and 54 percent of
the iron. Active mining sites (8 percent of the total inventoried) contributed 35
percent of the total net acid load and 40 percent of the iron. Approximately ZO
percent of the total sources inventoried contribute 85 percent of the net acid
load.
The Environmental Protection Agency' •"•» *•> estimated the total cost for
"at source" abatement of mine drainage and water treatment range from $218
million to $656 million for a ZO year period. Garvey(lO) believes the high fig-
ure is much too low and should be in the neighborhood of two billion dollars.
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The damaging environmental effects of mine drainage pollution in the
Monongahela River Basin has been a topic of discussion for over 60 years' »
Since at least the 1920's, mining activity along the Monongahela River has been
causing increasing problems for public water works located on the river(13).
The first comprehensive approach to mine drainage control in the drainage basin
was initiated in the 1930's by Federal and State governments through relief ad-
ministration programs such as Works Progress Administration, Federal Emer-
gency Relief Administration and Civil Works Administration^). Much of this
work consisted of the construction of air seals at abandoned mines. In 1938,
Hodge(14) concluded from his studies that air sealing of abandoned mines, di-
version of water from mines, and the construction of large flood control dams
were the best methods for assuring the maintenance of satisfactory stream con-
ditions for public water supplies, industrial uses and recreational activities.
The U. S. Public Health Service^' came to a similar conclusion in 1942. Their
study indicated there was a significant reduction in acid mine drainage as a re-
sult of the air sealing program, but chemical neutralization of mine drainage
was not economically feasible. Madison^ ' in a paper presented before the
American Chemical Society in 1950, stressed the significant amounts of organic
pollution carried by the Monongahela River and indicated that as effective mine
drainage controls are developed, the need for sewage treatment plants will in-
crease.
In the 1960's as a result of pollution studies by the U. S. Public Health
Service^) and others, the Federal Government became increasingly aware that
a serious interstate pollution problem was occurring in the Monongahela River
Basin. The Secretary of Health, Education and Welfare called an Interstate
Water Pollution Control Conference which was held in Pittsburgh, Pennsylvania
in December, 1963. The conferees established a Technical Committee to ex-
plore the means of abating pollution caused by coal mine drainage. The Com-
mittee established a project called the Monongahela River Mine Drainage Re-
medial Project and set up headquarters in Wheeling, West Virginia in 1964.
The Project was charged with making a study to determine sources, types and
amounts of pollution from coal mines, and the means and costs for abating such
pollution. The actual work of locating, sampling and describing the sources of
mine drainage began in 1965 and continued through 1968. Interim reports were
published by the Federal Water Pollution Control Administration' 1') and
Pash(18' 19) between 1968 and 1970. During this period, Ward and Wilmoth(20)
of the U. S. Geological Survey made a study of the effects of mine drainage on
the groundwater hydrology of the Monongahela River Basin. The final report
of the Monongahela River Mine Drainage Remedial Project was made public
by the Environmental Protection Agency(l< 2) at the second conference held in
Pittsburgh, Pennsylvania in August, 1971. The Advisory Work Group of the
Project was responsible for the first handbook on mine drainage pollution con-
trol costs(7).
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The activities of the Ohio River Valley Water Sanitation Commission'^)
since its beginning in 1948 in reducing pollution, especially mine drainage, in
the Monongahela River Basin should not be overlooked. This organization was
responsible for early interstate cooperation and studies on the fundamental
principles of acid mine drainage formation and methods of control'^ '. Based
on ORSANCO studies, Clark(^2) in 1964, analyzed the water quality trends in
the Monongahela River Basin during the past 50 years.
The extent of pollution in the Monongahela River Basin is discussed in
several studies on mine drainage pollution in Appalachia. Biesecker and Georg
of the U. S. Geological Survey made the first major regional stream quality
reconnaissance of Appalachian in 1965 and reported that the severity of mine
drainage pollution was substantially greater in the more heavily mined northern
third of the Appalachian region which includes the Monongahela River Basin.
The Federal Water Pollution Control Administration(24, 27) ^n their 1967 report,
revised 1969, came to a similar conclusion. The Appalachian Regional Com-
mission under the Appalachian Regional Development Act published a series of
reports in 1969 on acid mine drainage in Appalachia(8> 25-30)_
The Mine Drainage Abstracts prepared by Bituminous Coal Research,
Inc. (31) an(j their Coal Mine Drainage Library has facilitated the study of mine
drainage pollution and methods of control in the Monongahela River Basin. The
library, established in 1961, is sponsored by the Coal Industry Advisory Com-
mittee to ORSANCO. The preparation of the mine drainage abstracts is sup-
ported by the Pennsylvania Department of Environmental Resources. References
in the text of the report include the code designation used by Bituminous Coal
Research, Inc. in their bibliography, ex. (BCR 71-39).
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REFERENCES
1. U. S. Environmental Protection Agency, 1971, Mine Drainage Report to
Conferees: Enforcement Conf. , Pittsburgh, 22 p. (BCR 71-39)
2. U. S. Environmental Protection Agency, 1971, Summary Report, Monon-
gahela River Mine Drainage Remedial Project: Enforcement Conf. ,
Pittsburgh, 235 p. (BCR 71-40)
3. Sidio, A. D. and Mackenthun, K. M. , 1963, Report on Pollution of the
Interstate Waters of the Monongahela River System: U.S. Public Health
Service (BCR 63-24)
4. Shaw, J. R. , 1963, Statement; Chairman, ORSANCO, Conf. of Pollution
of Monongahela River and Its Tributaries, Pittsburgh, 30 p. (BCR 63-115)
5. Wilbar, C. L. , 1963, Water Pollution Control in the Monongahela River
Basin; Pa. Dept. Health, Div. Sanitary Eng. , Publ. No. 6, 86 p.
(BCR 63-23)
6. State and Interstate Conferees, 1971, Recommendations - Monongahela
Enforcement Conference: Pittsburgh, 2 p. (BCR 71-43)
7. Hyland, John, Project Director, 1966, Handbook of Pollution Control Costs
in Mine Drainage Management: Federal Water Pollution Control Adm. ,
prepared by Monongahela River Mine Drainage Remedial Project, 54 p.
(BCR 66-118)
8. Cyrus Wm. Rice and Co. , 1969, Engineering Economic Study of Mine
Drainage Control Techniques, Appendix B to Acid Mine Drainage in Appa-
lachia: Rept. to Appalachian Regional Comm. , 281 p. (BCR 69-79)
9. Lyon, W. A., 1971, Water Quality Management in the Monongahela River
Basin: Pa. Dept. Environ. Resources, Bur. Sanitary Eng. , Publ. No. 29,
102 p. (BCR 71-41)
10. Garvey, J. R. , 1971, Statement: Enforcement Conf., Monongahela River
and Its Tributaries, Pittsburgh, 2 p. (BCR 71-42)
11. Trax, E. C. , 1910, The Acid Waters of Western Pennsylvania: Eng. Record,
62_, 371-2 (BCR 10-1)
12. Roberts, T. P., 1912, Acids in Rivers and Mills. With Special Reference
to the Monongahela: Professional Memoirs, 4_, 501-4 (BCR 10-16)
13. Morgan, L. S. , 1931, Acidity and Hardness Difficulties at Monongahela
River Plants: Eng. News-Record, 106, 850 (BCR 30-17)
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14. Hodge, W. W., 1938, Effect of Coal Mine Drainage on West Virginia
Rivers and Water Supplies: W. Va. Univ. Bull. No. 18, _38_ (BCR 30-43)
15. U. S. Public Health Service, 1942, Ohio River Pollution Survey, Final
Report to the Ohio River Committee, Supplement "C", Acid Mine Drain-
age Studies: Office of Stream Sanitation, 68 p. (BCR 40-11)
16. Madison, K. M. , 1950, Pollution in the Allegheny, Monongahela and Ohio
Rivers in Allegheny County, Pennsylvania: Am. Chem. Soc. , 188th Nat.
Meet., Chicago (BCR 50-26)
17. Federal Water Pollution Control Administration, 1968, Stream Pollution
by Coal Mine Drainage, Upper Ohio River Basin: Ohio Basin Region,
Wheeling Field Station, Work Doc. No. 21 (BCR 68-64)
18. Pash, E. A., 1969, The Coal Mine Drainage Problem in Northern West
Virginia: Soil Conserv. Soc. Am., W. Va. Chapter, Ann. Meet.,
Jacksons Mill, 11 p. (BCR 69-57)
19. Pash, E. A., 1970, The Coal Mine Drainage Problem in Southwestern
Pennsylvania: Spring Geogr. Conf. Environ. Pollut. , Calif. State Coll.,
California, Pa., 13 p. (BCR 70-45)
20. Ward, P. E. and Wilmoth, B. M. , 1968, Ground-Water Hydrology of the
Monongahela River Basin in West Virginia: W. Va. Geol. Econ. Surv. ,
River Basin Bull. 1, 59 p. (BCR 68-173)
21. Ohio River Valley Water Sanitation Committee, 1964, Principles and
Guide to Practices in the Control of Acid Mine-Drainage: Coal Industry
Advisory Committee, 30 p. (BCR 64-28)
22. Clark, C. S. , 1964, Mine Acid Formation and Mine Acid Pollution Con-
trol: Proc. 5th Ann. Sym. on Ind. Waste Control, Frostburg State College,
Maryland, p. 50-73 (BCR 64-50)
23. Biesecker, J. E. and George, J. R. , 1966, Stream Quality in Appalachia
as Related to Coal-Mine Drainage, 1965: U. S. Geol. Surv. Circ. 526,
27 p. (BCR 66-18)
24. Federal Water Pollution Control Administration, 1967, Stream Pollution
by Coal Mine Drainage in Appalachia: 279 p. (BCR 67-182)
25. Appalachian Regional Commission, 1969, Acid Mine Drainage in Appala-
chia: Rept. to President, 126 p. (BCR 69-77)
26. Whitman, I. L. , Nehman, G. I., and Qasim, S. R. , 1969, The Impact of
Mine-Drainage Pollution on Industrial Water Users in Appalachia, Appendix
A to Acid Mine Drainage in Appalachia: Rept. to Appalachian Regional
Comm. , 253 p. (BCR 69-78)
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27. U. S. Army Corps of Engineers, 1969, The Incidence _and Formation of
Mine Drainage Pollution, Appendix C to Acid Mine Drainage in Appalachia:
Rept. to Appalachian Regional Comm. , 411 p. (BCR 69-80)
28. The Fantus Co., 1969, The Impacts of Mine Drainage Pollution on Location
Decisions of Manufacturing Industry in Appalachia, Appendix D to Acid Mine
Drainage in Appalachia: Rept. to Appalachian Regional Comm. , 304 p.
(BCR 69-81)
29. Robert R. Nathan Assoc. , Inc., 1969, Mine Drainage Pollution and Recre-
ation in Appalachia, Appendix E to Acid Mine Drainage in Appalachia:
Rept. to Appalachian Regional Comm. , 114 p. (BCR 69-82)
30. Katz, Max, 1969, The Biological and Ecological Effects of Acid Mine
Drainage with Particular Emphasis to the Waters of the Appalachian
Region, Appendix F to Acid Mine Drainage in Appalachia: Rept. to
Appalachian Regional Comm. , 65 p. (BCR 69-83)
31. Bituminous Coal Research, Inc., 1965, Mine Drainage Abstracts, A Bib-
liography: Annual Supplements, Sponsored by Coal Industry Advisory
Committee and Pennsylvania Department of Environmental Resources
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PART A
ABATEMENT OF COAL MINE DRAINAGE POLLUTION
AND MINING RELATED PROBLEMS
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STRIP MINE AND REFUSE BANK
BACKFILLING AND GRADING
TABLE OF CONTENTS
Page No.
Introduction 15
Cost Analysis 16
Access Roads 22
Clearing and Grubbing 22
Strip Mine Backfilling and Grading 28
Refuse Bank Contouring and Grading 32
Strip Mine and Refuse Bank Sealants 34
Summary 34
References 39
LIST OF TABLES
1. Strip Mine Reclamation Projects - Variables Affecting
Backfilling and Grading Costs 23
2. Coal Refuse Bank Reclamation Projects - Variables
Affecting Grading and Removal Costs 25
3. Clearing and Grubbing Cost Analysis 27
4. Strip Mine Backfilling and Grading Cost Analysis 30
5. Refuse Pile Contouring and Grading Cost Analysis 33
6. Strip Mine and Refuse Bank Sealant Cost Analysis 35
7. Summary of Cost Estimates - Strip Mine and Refuse
Bank Reclamation 36
LIST OF FIGURES
1. Contour Backfill 17
2. Pasture Backfill 18
3. Reverse Terrace Backfill 19
4. Swallow-Tail Backfill 20
5. Refuse Pile - Grading and Contouring 21
6. Strip Mine Backfilling and Grading Cost Analysis 29
-13-
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-------
STRIP MINE AND REFUSE BANK
BACKFILLING AND GRADING
Introduction
Since the primary purpose of this section is a cost analysis of strip
mine and refuse bank backfilling and grading, a discussion of the extent of
coal mining and its impact on the Monongahela River Basin is omitted. The
extent of acid mine drainage pollution in the Monongahela River Basin caused
by strip mining and refuse banks is discussed in recent publications by the
Environmental Protection Agency' »', U. S. Army Corps of Engineers^ ' r
and Lyon' ).
According to the U. S. Army Corps of Engineers Report' '"", 1969,
the objectives of basic strip mine and refuse bank reclamation are 1) water
quality through proper drainage, 2) the covering of toxic materials, and 3)
the revegetation of affected areas. This definition does not imply restora-
tion to approximate original contour and is primarily concerned with the con-
trol of acid mine drainage and siltation of receiving streams. Udall(^), U.S.
Department of Interior^ ' and Sullivan!?) suggest the inclusion of restoration
of reclaimed lands and water courses to productive uses compatible with ad-
jacent areas and restoration of pre-mining aesthetic values as additional
objectives for sound reclamation programs.
Prevention of acid mine drainage by burial of acid producing materials
and backfilling is based on the principle that in the absence of oxygen, the oxi-
dation of pyritic material is significantly reduced or prevented (Singer and
Stumm(8), NUS Corporation^9), Smith and Shumate^1*), Truax-Traer Coal
Company(H), Wilson, et al.(12)). Grube, et al.(13) and Caruccio and Pari-
zek(^) conclude that reduced acid mine drainage formation can be obtained
by segregating acid producing materials from spoil overburden and burying
these materials with clay or other impervious materials at the base of a back-
fill. Proper backfilling and grading of spoil material not only decreases the
volume of water flow through acid producing areas, but also reduces contact
time as implied by Hill(^).
The two major types of strip mine backfilling procedures in current
use in the Monongahela River Basin and surrounding areas are contour and
terrace methods. Several modifications of these two methods are employed
to meet the requirements of particular geographic and topographic conditions
and type of mining operation. A description of other backfilling methods is
presented in Krause(l6).
*This report was prepared by the U. S. Army Corps of Engineers for the
Appalachian Regional Commission. The majority of the report consists
of material previously published by FWPCA and the U. S. Bureau of Mines
in 1967-68. The FWPCA publication was revised for this report.
-15-
-------
Contour backfilling consists of moving spoil material back into the
pits and grading to approximately the original contour with an absence of
possible water collection depressions (Figure 1). This type of backfill is
generally restricted to slopes of 10° to 15° or less because of problems
resulting in increased erosion and subsequent siltation of receiving waters
as pointed out by Cyrus Wm. Rice and Company^?). Contour backfilling
has been recommended on the majority of Pennsylvania reclamation projects
but is of limited use on most reclamation projects in West Virginia because
of slope limitations in the West Virginia part of the Monongahela River Basin.
Terrace backfills involve the grading of spoil to form a "modified
bench" gently sloping either toward or from the highwall area. Sufficient
grading is required to insure adequate burial of acid producing substances
and usually includes outslope and highwall slope limitations. Highly frac-
tured highwalls should be "topped" to avoid possible safety and drainage
interference problems (Hill'*")). Particular attention should be given to
proper backfilling techniques on the "outslope" areas to reduce the possi-
bility of landslides.
There are several variations of terrace backfills of which pasture
backfill (Figure 2), reverse terrace backfill (Figure 3) and swallow-tail
backfill (Figure 4) are the most common. These variations are primarily
designed to divert or reduce the volume of surface and ground water flow
through potential acid producing areas in the backfilled spoil (Bullard(19))t
The backfilling and grading of deep mine refuse piles usually re-
quires some type of physical sealing to reduce the volume of acid mine
drainage. The most commonly used sealants are soil and clay, but bitum-
inous products and possibly plastics could be used if economically feasible.
Adequate precautions should be taken to avoid possible degradation of bor-
row areas.
Grading of refuse is performed in such a manner as to limit erosion
and the formation of water collection depressions (Figure 5). Compaction
of refuse may be necessary to reduce percolation of water through the acid
producing materials. In some areas, slope characteristics will necessitate
removal of refuse as the only feasible method of reclamation. Removal of
refuse banks is probably most feasible when performed in conjunction with
adjacent strip mine reclamation projects. The refuse can be placed in the
bottom of strip pits prior to backfilling.
Cost Analysis
The cost data presentation is limited to an analysis of the costs
for recent abandoned strip mine and refuse bank reclamation projects
in the Monongahela River Basin and surrounding areas. Although this
limitation significantly reduces the amount of available data that can be
used, it does minimize the errors that can be introduced by variables
in geographic location, the differences in topography, on site physical
-16-
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-21-
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and chemical characteristics, methods of mining, and the inequalities
in bond forfeiture reclamation projects from one area to another. To
better facilitate cost estimation, cost analyses have been divided into sev-
eral major categories. Since some projects, depending on physical and chemi-
cal conditions present, will not require all aspects of the reclamation program,
it will be possible to delete those parts not applicable. Administrative, engi-
neering and post-reclamation evaluation costs as well as cost of mine seals,
water diversion, spoil neutralization and revegetation have been omitted from
this section. It will, therefore, be necessary to review other sections of the
report to arrive at the total strip mine or refuse pile reclamation cost esti-
mate.
It is recommended that a uniform method of reporting data be developed
and adopted by state and federal agencies involved in reclamation programs.
This not only would make future reclamation cost estimates more meaningful,
but would also increase the efficiency of data retrieval and enhance the possi-
bility of computerization of data. The variables that should be considered in
reporting strip mine and refuse bank reclamation project data are presented
in Tables 1 and 2. These variables should also be considered in the planning
stage in order to obtain a more meaningful estimate of reclamation costs.
Access Roads - Very little information exists on access road construc-
tion costs for strip mine and refuse bank reclamation. In most instances, this
cost has been included in the backfilling and grading costs. From the limited
information available, it appears the construction costs for access roads in-
cluding clearing and grubbing, ranges from $2.50 to $3, 00 a lineal foot. An
increase in the cost of construction can be expected if culverts or other drain-
age structures are needed.
Clearing and Grubbing - The costs of clearing and grubbing range from
$33.54 to $700.. 00 per acre with a mean of $218.77 per acre. Forty three re-
cent reclamation projects were reviewed and only seven included sufficient
data to permit an estimation of clearing and grubbing costs. A summary of
this data is presented in Table 3. The costs reported by McNay(20) for clear-
ing and grubbing at Moraine State Park, Pennsylvania are based on work time
and the average operating cost of a D-7 Dozer and do not represent actual
recorded values.
The higher costs per acre for clearing and grubbing can be attributed
to density of growth and a requirement on some projects to cut pulpwood for
the landowner (Scott, et al.' '); slope of terrain and weather conditions
(McNay(20)); the amount of partially buried timber encountered (Griffith, et
al. (22)); and the amount of scrap and solid waste present (Jones( '). The
overall reclamation cost may be reduced if brush and trees are chipped and
used as mulch instead of burying and burning.
-22-
-------
TABLE 1
STRIP MINE RECLAMATION PROJECTS
VARIABLES AFFECTING BACKFILLING AND GRADING COSTS
1. Geographic location
2. Topographic setting (Original, pre-reclamation and final ground slopes)
3. Type of strip mine
a) Area b) Contour c) Area-contour d) Other
4. Coal seams mined and thickness
5. Inclination of coal seams in back of highwall
a) Dip b) Rise C) Horizontal
6. Condition of coal seams in back of highwall
a) Not mined b) Auger mined c) Drift mined (Entries opened or caved)
d) Mine workings exposed by stripping operation
7. The probable hydraulic head that could develop if coal in back of highwall
was mined
8, Strip mine area information
A. Length, width and area (acres) covered by spoil before reclamation
B. Highwall height (maximum and average height)
C. Highwall length
D. Number of cuts
E. Total area affected during reclamation in acres (including area above
highwall and outside outs lopes)
F. Volume of spoil to be moved (cubic yards)
G. Average haul distance for backfilling and grading
H. Texture of spoil
I. Amount of large rock and material requiring special handling (mining
timbers, machinery and debris, junked cars, and other solid waste)
J. Amount and reactivity of pyritic material (mineralogy and mode of
occurrence, e.g., finely dispersed; single crystals or crysta] aggre-
gates; coatings on joint surfaces; in form of lenses, layers or nodules;
"sulfur balls"; pyritic shales; etc.)
K. Clearing and grubbing requirements
9. Type of backfill
a) Contour b) Pasture-reverse slope c) Swallowtail
d) Head of hollow e) Submergence f) Other
10. Physical sealants for covering toxic material
a) None b) Clay c) Bituminous material c) Plastic material
e) Other
11. Compaction desired
a) None b) Only toxic materials c) All spoil material with exception
of upper layer (1 to 3 feet)
-23-
-------
TABLE 1 (continued)
12. Accessibility factors
A. Right-of-way problems
B. Ingress and egress construction (include clearing and grubbing for
access and post-construction revegetation)
C. Other factors affecting access
13. Surface and subsurface ownership of strip mined area. Also ownership
of properties for ingress and egress.
a) Public b) Private c) In process of being acquired or lien placed on
property d) Abandoned e) Temporary easement f) Other
14. Time of year reclamation performed
15. Weather conditions during reclamation period(s)
16. General contractor and subcontractors
17. Types of construction equipment used and equipment records if available
18. Source of project funding
19. Productive use to be made of reclaimed land
20. General observations and recommendations
A. Difficulties in writing an effective bid proposal
B. Contractual problems during construction
C. Unanticipated problems requiring change orders
D. Recommendations and possible solutions that could in future projects
avoid the difficulties encountered in A, B and C
21. Evaluation of the overall success or failure of the project (one, two and
five years later)
A. Percent of pollution reduction (acid mine drainage and siltation)
B. Cost per pound of acid reduction
C. Effectiveness of soil treatment if any
D. Growth and survival of vegetation
E. Aesthetic evaluation
-24-
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TABLE 2
COAL REFUSE BANK RECLAMATION PROJECTS
VARIABLES AFFECTING GRADING AND REMOVAL COSTS
1. Geographic location
2. Topographic setting (Original, pre-reclamation and final ground slopes)
3. Coal refuse bank area information
A. Length, width and area (acres) before reclamation
B. Height of refuse bank (maximum and average height)
C. Total area to be affected during reclamation in acres (including
areas outside perimeter of refuse bank and burial sites)
D. Volume of refuse to be graded or removed (cubic yards)
E. Average haul distance for grading
F. Average haul distance to burial site(s)
G. Texture of refuse
H. Amount of large rock and material requiring special handling (mining
timbers, machinery and debris, junked cars, and other solid waste)
See Item 8.C
I. Amount and reactivity of pyritic material (mineralogy and mode of
occurrence, e.g., finely dispersed; single crystals of crystal aggre-
gates; coatings on joint surfaces; in form of lenses, layers or nodules;
"sulfur balls"; pyritic shales; etc.)
J. Clearing and grubbing requirements
4. Method of refuse bank construction
a) Tippler form b) Layer piling c) Layer piling with clay d) Other
5. Coal seam that was deep mined and its characteristics
6. Type of roof and bottom rock in the deep mine
7. History of refuse bank
A. Years during which refuse bank was being constructed and last year
of placement of refuse on bank (Mining methods have changed over
the years and the composition of banks are variable depending on
mining method, coal seam mined, type of roof and bottom rock, and
age of bank)
B. Has refuse bank ever been on fire or is part of refuse bank burning
now?
C. Has refuse bank been cleaned for waste coal?
8. If refuse bank is burning
A. Volume of burning refuse (cubic yards)
B. Special procedures or methods of handling burning refuse
C. Number and size of large lumps of fused ash requiring special
handling
9. Reclaimable resources that can offset cost of reclamation
a) Coal b) Red dog c) Other
10. Type of reclamation
a) Grading b) Grading and sealing c) Other
-25-
-------
TABLE 2 (continued)
11. Physical sealants for covering toxic material
a) None b) Clay c) Bituminous material d) Plastic material e) Other
12, If clay is used as a sealant
A. Size of borrow area and volume of material needed for sealing (cubic yards)
B. Location, accessibility, and distance from borrow area to refuse bank
C. Clearing and grubbing requirements at borrow area
D. Revegetation requirements at borrow area
13, Compaction desired
a) None b) All of refuse material with exception of upper layer (1 to 3 feet)
c) All of the refuse material and all but upper layer of clay covering (1 to 3
feet d) Other
14, Accessibility factors
A. Right-of-way problems
B. Ingress and egress construction (include clearing and grubbing for
access and post-construction revegetation)
C. Other factors affecting access
IS. Ownership of refuse bank and surface area. Also ownership of properties
for ingress, egress and borrow areas.
a) Public b) Private c) In process of being acquired or lien placed on
property d) Abandoned e) Temporary easement f) Other
16, Time of year reclamation performed
17. Weather conditions during reclamation period(s)
18, General contractor and subcontractors
19. Types of construction equipment used and equipment records if available
20. Source of project funding
21, Productive use to be made of reclaimed land
22, General observations and recommendations
A. Difficulties in writing an effective bid proposal
B. Contractual problems during construction
C. Unanticipated problems requiring change orders
D. Recommendations and possible solutions that could in future projects
avoid the difficulties encountered in A, B and C.
23. Evaluation of the overall success or failure of the project (one, two and
five years later)
A. Percent of pollution reduction (acid mine drainage and sillation)
B. Cost per pound of acid reduction
C. Effectiveness of soil treatment if any
D. Growth and survival of vegetation
E. Aesthetic evaluation
-26-
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-27-
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Strip Mine Backfilling and Grading - The strip mine backfilling and
grading costs used in preparing the cost analysis are presented in Table 4.
For all methods of backfilling and grading, the costs per acre range from
$211. 57 to $2, 007. 00 and the mean cost is $859. 78 per acre.
The cost of contour-type backfilling and grading ranged from $472.00
to $1,520.00 per acre and the mean is $922.66. Table 4 indicates that ter-
race-type reclamation methods, which include the pasture reverse slope and
swallowtail methods, are about 43 percent lower in cost per acre compared
to the contour-type. The average cost for terrace-type backfilling and grad-
ing is $525. 98 per acre and costs range from $211.57 to $918.00 per acre.
Combination contour-terrace reclamation methods ranged from $472. 00 to
$2, 007. 00 per acre and the mean is $1, 263. 84.
A review of the projects show there is no relationship between the
number of acres reclaimed and the backfilling and grading costs per acre
for any of the reclamation methods. A definite relationship does exist for
the contour-type reclamation method between the volume of spoil per unit
area and the cost per unit volume of backfilling and grading (Figure 6).
The mathematical expression for this relationship is
-1.82760
y = 760.2 x
or
log y = -1.82760 log x +2.88094
where y is the cost per unit volume (cents/cubic yard) and x is the total vol-
ume of spoil to be moved per unit area (cubic yards/acre).
Because of the lack of data on volume for the majority of terrace-
type reclamation projects that were reviewed, the relationship between cost
per unit volume and total volume of spoil per unit area to be moved can only
be inferred. If it is assumed that differences in cost per cubic yard are pro-
portioned to differences in cost per acre when comparing costs of contour and
terrace-type reclamation methods, it would be possible to use the same re-
lationship developed for the contour reclamation method by reducing total cost
by an appropriate cost differential factor. Using the cost per unit area data
presented in Table 4, it appears the cost of the terrace-type reclamation
method is about 57 percent of the contour-type. This value compares favor-
ably with figures presented by Cyrus Wm. Rice and Company'-*- ' / in their 1969
report to the Appalachian Regional Commission in which cost estimates for
terrace reclamation methods were 53 percent of the contour-type.
Using the 57 percent differential as a reducing factor, the following
inferred mathematical expression for terrace-type backfilling and grading costs
is possible.
-28-
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-1.82760
y = 433.3 x
or
log y = -1.82760 log x +2.63679
Again, y is the cost per unit volume (cents/cubic yard) and x is the
total volume of spoil to be moved per unit area (cubic yards/acre). Because
of the limited data used in formulating this expression, it should only be used
for a rough approximation of terrace-type backfilling and grading costs.
The amount of spoil that has to be moved during reclamation is the
principal factor in the differences in backfilling and grading costs per unit
area. In the cost analysis made by Cyrus Wm. Rice and Co.( ', it was es-
timated that the contour reclamation method required movement of 75 per-
cent of the total spoil present while the terrace-type method required move-
ment of only 25 to 40 percent of the total spoil. Other factors responsible
for greater costs for the contour method are the increased amount of buried
timbers encountered (Griffith, et al.' ') and a longer average haul distance
(Oldham(25)).
Increased overall backfilling and grading costs as compared to pre-
reclamation estimates can be attributed to several factors. McNay^^/ reports
that costs were greater because of frozen ground conditions, the number of
sandstone slabs larger than one cubic yard, and the spoil texture. Scott,
et al.'2!) lists separation of toxic materials, adverse weather conditions, and
highwall "topping" as the factors which increased backfilling and grading costs.
A possible cost offset which may be employed during certain strip mine
reclamation operations, where the highwall area has been mined, is recovery
of coal. Proponents of this method of cost offset usually concur that it is gen-
erally restricted to areas of shallow mine cover where there has been limited
underground mining because of the expense of separating coal from collapsed
mine workings. However, it is the contention of some individuals that even
though this procedure may be inefficient from the standpoint of coal recovered
vs. cost of recovery, it may be economical when considering savings on mine
seals and mine drainage treatment costs. An individual site would have to be
studied before a conclusion could be made as to whether this method would re-
sult in an overall cost reduction.
Refuse Bank Contouring and Grading - The majority of refuse bank rec-
lamation projects have been performed in conjuction with strip mine and sub-
sidence area backfilling operations. Because of the ambiguity and incomplete-
ness of records for many of the refuse bank reclamation projects, only those
projects permitting a somewhat reliable cost analysis of contouring and grading
costs are summarized in Table 5. It must be emphasized that these costs only
reflect the cost of contouring and grading of refuse and do not include the cost
of access road construction, clearing and grubbing, sealants, water diversion
and revegetation.
-32-
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Based on Table 5, the cost of contouring and grading ranged from.
$100. 00 to $3, 000. 00 per acre and the mean is $1, 008. 54. The cubic yard
cost ranges from $0.333 to $1.00 and the average cost is $0.758 cubic yard.
Only one of the projects reviewed, SL 109-1C in Indiana County, Pennsylvania,
involved the removal and deposition of refuse. During one phase of the pro-
ject, 47, 500 cubic yards were removed at any average cost of $0.944 cubic
yard. This cost per cubic yard is approximately three times the average cost
reported by Daniels on and White(2?) for refuse disposal at two active coal
mines in Kentucky and Alabama. The difference in cost probably can be attrib-
uted to haul distances, use of on-site equipment and the advantage of removal
at an active site.
Future reclamation projects involving removal of refuse could be com-
bined with refuse utilization where economically feasible. Refuse material has
been crushed for secondary coal recovery, for base materials for roadways and
parking areas, and for production of anti-skid material and cement (Greenlee
and Spicer(28)). Production of brick (Environmental Science and Technology^)),
carbonate bonding of refuse for roadway use and as a sealant, and sulfur re-
covery (Black, Sivalls and Bryson, Inc. (30, 31)) have been demonstrated and
may possibly be economical uses for coal mine refuse.
Strip Mine and Refuse Bank Sealants - The cost of borrow and spreading
of sealants over toxic material during strip mine and refuse bank reclamation
ranged from $0.26 to $2.00 per cubic yard and the mean was $0.406 based on
the data presented in Table 6. All but one of the projects reviewed employed
soil as a sealant. The soil material was used to cover the toxic material to re-
duce infiltration of water and to promote revegetation. The soil was approved
run of the bank material and can be loosely classified as "topsoil. " The high
cost of $2.00 per cubic yard on Project SL 111-1 can be attributed to an unbal-
anced bid and it should be noted only a total of 5, 000 cubic yards was needed for
the project. The only project that employed a sealant classified as clay had a
cost of $1.75 per cubic yard. There does not appear to be a relationship be-
tween cost of sealant and borrow area distance for the projects reviewed, but
haul distances were less than one mile.
Little data exists for sealants other than "clay" and soil. The MSA Re-
search Corp. (32) in 197! conducted studies on several possible sealants for
sealing toxic material in strip mines and refuse banks. The sealants included
polyethylene sheeting, urethane foam, linseed oil, polyvinyl chloride cacooning
and fly ash. Only polyethylene sheeting and urethane foam were effective in
reducing water percolation. The cost of polyethylene sheeting was estimated
at $4, 356. 00 per acre and urethane foam at $10, 018. 00 per acre. The life ex-
pectancy of the sheeting is three to five years according to Kamal'-^ ). The
costs do not include contouring and grading. It is highly improbable that these
sealants can be economically applied in reclamation projects at the present time.
Summary - The cost estimates were made using data from recent aban-
doned strip mine and refuse bank reclamation projects in the Monongahela River
Basin and surrounding area. Table 7 is a summary of the cost estimates.
-34-
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Based on analysis of strip mine backfilling and grading costs for pro-
jects in both Pennsylvania and West Virginia, it appears updated (1972) costs
would be about:
Contour type $l,000/acre
Terrace type 600/acre
An analysis using only Pennsylvania projects, which included contour
and combination contour-terrace methods, indicates the average cost per acre
is a little over $1,200. The strip mine backfilling and grading costs were
much lower for West Virginia projects, but no information was available for
any of the West Virginia projects on volume of material moved per acre and
cost/cubic yard.
Since Federal and State reclamation requirements are becoming more
stringent, and since West Virginia reclamation requirements prior to passage
of new surface mining reclamation regulations in 1971 were not as strict as
Pennsylvania's, a cost of $l,250/acre is estimated for strip mine backfilling
and grading in the Monongahela River Basin.
This cost estimate of $l,250/acre is for backfilling and grading old
abandoned operations in which the spoil material is mixed. Although it is
difficult to separate actual stripping costs from reclamation costs for active
operations meeting State and proposed Federal reclamation regulations, it is
the opinion of individuals in the coal mining industry that complete reclama-
tion including revegetation cost can be accomplished for $200 to $300/acre
above actual stripping cost, if the work is performed at the time of stripping.
Accomplishing this work at such a low cost requires pre-planning and proper
development of the strip mine operation. The acidic materials must be sep-
arated and buried during stripping, the backfilling performed as stripping
progresses and the top soil stockpiled for later covering of the completed op-
eration, all this work being performed with on-site equipment used in the
stripping operation.
This estimated cost for active operations conducted in accordance with
the above methods and procedures does not imply that bond forfeiture require-
ments are adequate or inadequate. A poorly planned stripping operation in
which the operator goes bankrupt or forfeits his bond can conceivably cost as
much to reclaim as an old abandoned strip mine.
There is very little reliable information available on the cost of refuse
bank contouring and grading. Therefore, based on limited information and dis-
cussions with individuals familiar with this work, a cost of $1, 000/acre is
estimated. This cost estimate would not include a soil cover. Covering the
graded refuse with soil should cost about $2, 500/acre ($0. 50/cubic yard).
-37-
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Refuse bank removal and burial is another item on which there is very
little reliable information, probably because much of this work to date has
been performed in conjunction with strip mine reclamation and costs are not
separated. Major factors effecting a cost estimate for this work are haul dis-
tance, volume of material to be moved, volume of large rock and material
requiring special handling, and compaction requirements at burial site (see
Table 2 for other factors).
For general planning purposes in the Monongahela River Basin, a cost
estimate of $1.00/cubic yard should be used for refuse bank removal and burial.
Where specific site information is available, cost estimates should be based on
recognized construction estimating practices, taking into consideration haul
distances, hourly wage and equipment rates, site accessibility and other known
factors that would affect removal and burial costs. Soil covering at the burial
site should be estimated at $0. 50/cubic yard, i.e., $0. 50/square yard of cover.
An average cost of $300/acre for clearing and grubbing is satisfactory
for estimates in the Monongahela River Basin, but all sites will not require this
item. Most of the refuse banks, culm ponds and some highly acidic strip mines
should be more or less barren.
-38-
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REFERENCES
1. Environmental Protection Agency, 1971, Summary Report, Monongahela
River Mine Drainage Remedial Project: Enforcement Conf. , Pittsburgh,
235 p. (BCR 71-40)
2. Environmental Protection Agency, 1971, Mine Drainage Report to Con-
ferees: Enforcement Conf., Monongahela River & Its Tributaries, Pitts-
burgh, 22 p. (BCR 71-39)
3. U. S. Army Corps of Engineers, 1969, The Incidence and Formation of
Mine Drainage Pollution, Appendix C to Acid Mine Drainage in Appalachia:
Rept. to Appalachian Regional Comm. , 411 p. (BCR 69-80)
4. Lyon, Walter A., 1971, Water Quality Management in the Monongahela
River Basin: Pa. Dept. Environmental Resources, Bur. Sanitary Eng.
Publ. No. 29, 102 p. (BCR 71-41)
5. Udall, S. L. , 1966, Study of Strip and Surface Mining in Appalachia, An
Interim Report to the Appalachian Regional Commission: U.S. Dept. of
Interior, 78 p. (BCR 66-59)
6. U.S. Dept. of Interior, 1967, Surface Mining and Our Environment, Special
Report to the Nation: 124 p. (BCR 67-82)
7. Sullivan, G. D. , 1967, Current Research Trends in Mined-Land Conser-
vation and Utilization: Am. Inst. Mining Eng. Preprint No. 67F65, 18 p.
(BCR 67-11)
8. Singer, P. C. and Stumm, W. , 1969, Oxygenation of Ferrous Iron, The
Rate Determining Step in the Formation of Acidic Mine Drainage: Fed.
Water Quality Adm., Res. Ser. DAST 28, 216 p. (BCR 69-64)
9. NUS Corporation, 1971, The Effects of Various Gas Atmospheres on the
Oxidation of Coal Mine Pyrites: Environmental Protection Agency, Water
Quality Office, Res. Ser. 14010 ECC 08/71, 140 p. (BCR 71-
10. Smith, E. E. and Shumate, K. S. , 1970, A Study of the Sulfide to Sulfate
Reaction Mechanism as it Relates to the Formation of Acid Mine Waters:
Fed. Water Quality Adm. , Res. Ser. 14010 FPS 02/70, 115 p. (BCR 70-3)
11. Truax-Traer Coal Company, 1971, Control of Mine Drainage from Coal
Mine Mineral Waste: Environmental Protection Agency, Water Quality
Office, Res. Ser. 14010 DDH 08/71, 148 p. (BCR 71-69)
12. Wilson, L. W. , Matthews, N. J. and Stump, J. L. , 1970, Underground
Coal Mining Methods to Abate Water Pollution: Environmental Protection
Agency, Water Quality Office, Res. Ser. 14010 FKK 12/70, 50 p. (BCR
70-120)
-39-
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13. Grube, W. E. , Jr., et al. , 1971, Mine Spoil Potentials for Water Quality
and Controlled Erosion: Environmental Protection Agency, Water Quality
Office, Res. Ser. 14010 EJE 12/71 (BCR 71-72)
14. Caruccio, F. T. and Parizek, R. R., 1967, An Evaluation of Factors In-
fluencing Acid Mine Drainage Production from Various Strata of the Alle-
gheny Group and the Ground Water Interactions in Selected Areas of Western
Pennsylvania: Pa. State Univ. Spec. Res. Rept. SR-65, 213 p. (BCR 67-87)
15. Hill, Ronald D., 1969, Reclamation and Revegetation of 640 Acres of Sur-
face Mines, Elkins, West Virginia; Intern. Sym. Ecology Revegetation of
Drastically Disturbed Areas, University Park, Pa., by Pa. State Univ.,
47 p. (BCR 69-53)
16. Krause, R. R., 1972, Mining and Reclamation Techniques to Control Mine
Drainage; Fourth Sym. Coal Mine Drainage Res. Preprints, Pittsburgh,
p. 425-30 (BCR 72-
17. Cyrus Wm. Rice and Co., 1969, Engineering Economic Study of Mine
Drainage Control Techniques. Appendix B to Acid Mine Drainage in
Appalachia; Rept. to Appalachian Regional Comm., 28 p. (BCR 69-79)
18. Hill, Ronald D., 1971, Restoration of a Terrestrial Environment - The
Surface Mine: Bull. Assoc. Southeastern Biologists, JJ3(3)p. 107-16
(See BCR 71-11)
19. Bullard, W. E., 1965, Acid Mine Drainage Pollution Control Demonstra-
tion Program Uses of Experimental Watersheds; Intern. Assoc. Scientific
Hydrology Sym. , Budapest, p. 190-200 (BCR 65-68)
20. McNay, L. M. , 1970, Surface Mine Reclamation, Moraine State Park,
Pennsylvania: U.S. Bur. Mines, Inf. Circ. 8456, 28 p. (BCR 70-52)
21. Scott, R. B., Hill, R. D. , and Wilmoth, R. C. , 1970, Cost of Reclama-
tion and Mine Drainage Abatement - Elkins Demonstration Project: Am.
Inst. Mining Eng. , SME Fall Meet. , St. Louis, Preprint No. 70AG349,
22 p. (BCR 70-70)
22. Griffith, F. E. , Magnuson, M. O. and Kimball, R. L., 1966, Demonstra-
tion and Evaluation of Five Methods of Secondary Backfilling of Strip-
Mine Areas: U. S. Bur. Mines Rept. Invest. 6772, 17 p. (BCR 66-159)
23. Jones, Robert, 1972, Personal Communication: Jones and Brague Mining
Company, Blossburg, Pa.
24. Grim, Elmore, C. , 1972, Personal Communication: Unpublished informa-
tion compiled by Mr. Grim, Surface Mining Specialist, Environmental
Protection Agency, National Environmental Research Center, Cincinnati
-40-
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25. Oldham, F. S. , 1972, Personal Communication: Director, Bureau of
Planning and Developmental Research, Pennsylvania Department of
Environmental Resources
26. Molinski, A. E. , 1972, Personal Communication; Unpublished infor-
mation compiled by Mr. Molinski, District Engineer, Office of Engineer-
ing and Construction, Pennsylvania Department of Environmental Resources,
Ebensburg Office
27. Danielson, V. A. and White, D. H., 1969, Waste Disposal Costs at Two
Coal Mines in Kentucky and Alabama: U. S. Bur. Mines Inf. Circ. 8406,
27 p. (No BCR No.)
28. Greenlee, J. K. and Spicer, T. S., 1971, Crushing Anthracite Refuse:
Pa. State Univ. Spec. Res. Kept. SR-87, 67 p. (No BCR No.)
29. Environmental Science and Technology, 1972, Tekology Process Turns
Garbage into Building Materials; _6_ (6), p. 502-03
30. Black, Sivalls and Bryson, Inc., 1971, Carbonate Bonding of Coal Refuse;
Environmental Protection Agency, Water Quality Office, Res. Ser. 14010
FOA 02/71, 44 p. (BCR 71-
31. Black, Sivalls and Bryson, Inc., 1971, Study of Sulfur Recovery from
Coal Refuse: Environmental Protection Agency, Water Quality Office,
Res. Ser. 14010 FYY 09/71, 67 p. (BCR 71-
32. MSA Research Corp., 1971, Mine Refuse Pile Coverings to Reduce Water
Percolation; Sum. Rept. to Pa. Dept. of Environ. Resources, 32 p.
(BCR 71-8)
33. Kamal, MusaR., ed., 1967, Weather ability of Plastic Materials: Inter-
science Publishers
-41-
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REVEGETATION OF LANDS DISTURBED BY COAL MINING
TABLE OF CONTENTS
Page No.
Introduction 45
Cost Analysis 45
Use of Soil Tests and Factors Affecting Reclamation Decisions 48
Green Thumb Program 53
References 54
LIST OF TABLES
1. Variables Affecting Revegetation Costs 46
2. Cost Analysis for Revegetation 50
LIST OF FIGURES
1. Soil Test Report - Pennsylvania State University 49
-43-
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REVEGETATION OF LANDS DISTURBED BY COAL MINING
Introduction
To insure the success of strip mine and refuse bank reclamation pro-
jects adequate vegetation cover must be established (U.S. Department of
Agriculture' *•>). Revegetation of areas disturbed by coal mining prior to 1940
consisted almost entirely of tree planting (U.S. Department of Interior' ').
However, it has been demonstrated from past reclamation experience that an
easily established ground cover (grasses and legumes) is needed for erosion
control and initial surface stabilization (Struthers and Vimmerstedt'^'). The
most logical approach to revegetation appears to be the methods outlined by
Hill''*/ in which a ground cover is rapidly established followed by overplanting
with trees.
Low pH is the most common factor responsible for the failure of re-
vegetation on strip mines and refuse banks (Czapowskyj and McQuilkin(^);
Mellinger(6) and Smith, et al. (7)). The Truax-Traer Coal Company(S) and
Tyner and Smith(9) found that repeated applications of lime were necessary
to enable the establishment of a ground cover. Capp and Adams(lO) report
similar results with the application of fly ash to increase buffering capacity
of spoils. However, Magnuson and Kimball( •'••'•) conclude that application of
lime on spoils having an initial pH above 4. 5 is not likely to increase sur-
vival rate. Other factors responsible for revegetation failures are salt tox-
icities (Bergl-^); Berg and Vogel(^3); Beyer and Hutnikf^'*) ancj Coleman,
et al.'")), nutrient deficiencies (Cummins, et al.^0); Hart and Byrnes(17)
and Struthers( ^), soil temperatures and moisture content (Maguire(19) and
Marx and Bryam^/). A detailed description of adverse factors affecting the
revegetation of strip mines and refuse banks is presented in a publication by
Nicholas and Hutnik(21).
Since soil characteristics can vary considerably from one reclamation
site to the next (Sullivan(22))( it is unlikely that uniform planting recommen-
dations can be developed. However, soil mapping of spoils to obtain repre-
sentative samples as suggested by Limstrom and Merz'"', Paton, et al. (24)
and Grube, et al.(") can supply the information needed to develop planting
recommendations at specific sites. Krause(^") recommends greenhouse tests
of various spoils to get more specific information on the capability of the mat-
erials to produce and sustain vegetation. Grube, et al.(25) concurs and rec-
ommends independent soil analysis prior to soil treatment, fertilizing and
seeding.
Cost Analysis
To facilitate future cost estimates for revegetation, it is recommended
that a standard format be developed for reporting costs. A listing of the vari-
ables that can affect revegetation costs in strip mine and refuse bank reclama-
tion is presented in Table 1. In Table 1, soil treatment, seeding and mulching
-45-
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TABLE 1
VARIABLES AFFECTING REVEGETATION COSTS*
LANDS DISTURBED BY COAL MINING
1. Soils Analysis (Based on soil mapping to obtain representative samples)
A. pH Soil
B. pH Buffer**
C. Soil Nutrient Level (P, K, Ca and Mg)
D. Moisture Content
E. Drainage Characteristics of Soil
F. Organic Content
G, Toxic Salts
H. Other Factors
2. Greenhouse Analysis (Using proposed soil treatment, seeding mixtures
and mulching)
3. Recommended Soil Treatment (Methods, applications, rates, year and
months)
A. Lime or Ground Limestone (tons/acre)
B. Fertilizer (Ibs. of N-P2O5-K2O/acre)
4. Recommended Vegetation (Planting methods, species or varieties, rates,
year and months)
A. Ground Cover
1. Grasses (Ibs./acre)
2. Legumes (Ibs./acre)
B. Trees and Shrubs, seedling or saplings (number/acre)
C. Special Wildlife or Ornamental Plantings (description and number/
acre)
5. Recommended Mulching (None, one or more of the following)
A. Hay or Straw (tons/acre)
B. Wood Cellulose Fiber (Ibs. /acre)
C. Hardwood Bark (cubic yards/acre)
D. Chipped Brush and Trees from Clearing and Grubbing (cubic yards/
acre)
E. Other Mulch
6. Vegetation Survival Analysis (1, 2, 3 years or a longer period following
initial planting)
A, Percent of Ground Cover (including survival of individual varieties
of grasses and legumes)
-46-
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TABLE 1 (Continued)
B. Percent of Trees and/or Shrubs (including survival of individual
species or varieties)
C. Size of Surviving Trees and/or Shrubs (below average, average,
above average for age of each species or variety)
D. Reasons for Poor Survival of Specific Grasses, Legumes, Trees
and Shrubs (non-adaptive to soil conditions, climatic factors, com-
petition from other species or other factors)
7. Volunteer Vegetation (1, 2, 3 years or a longer period following initial
planting)
A. Grasses (species or varieties and percent of ground cover)
B. Weeds, Wildflowers and Other Plants (species and percent of ground
cover)
C. Trees and Shrubs (species, size and percent of cover)
8. Subsequent Recommended Soil Treatment
A. Same Information as Item 3
9. Subsequent Recommended Vegetation
A. Same Information as Item 4
10. Soils Analysis (1, 2, 3 years or a longer period following initial planting)
A. Same Information as Item 1
B. Weathering Characteristics of Soil
#These variables are in addition to those factors listed in Tables 1 and 2 of
the section titled "Strip Mine and Refuse Bank Backfilling and Grading".
**Used to determine lime requirement and to calculate the milli-equivalents
of hydrogen ions per 100 gm soil (me H"*~ per 100 gm soil). The second
value is used in calculation of the cation exchange capacity (CEC).
-47-
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are treated as separate operations, but in actual practice one, two or all
three of the operations may be combined into one operation, as in the ex-
ample of hydroseeding. Also even when these operations are combined or
performed separately, the total requirements for soil treatment, seeding
and mulching may not be applied at the same time. As an example, seed
and one half of the fertilizer requirement may be hydroseeded in one appli-
cation in the spring and the remainder of the fertilizer applied in the fall.
In preparing this section, only information from recent strip mine
and refuse bank reclamation projects in the Monongahela River Basin and
surrounding area was used. Table 2 presents a tabulation of revegetation
costs for these projects. Revegetation costs ranged from $90 to $500 per
acre and the mean cost was $278.56. A wide variety of soil treatment and
planting methods is represented on this table and variable degrees of reveg-
etation success is reported. Generally, figures are presented as lump sums
or cost per acre. Where possible, the application rates of limestone and
fertilizer are included. Because of the limited sample size and a lack of
information on initial soils analysis, no conclusions can be made on cost of
planting various species or varieties of grass, legumes, trees and shrubs
or possible relationships between area, spoil pH and revegetation costs.
A further difficulty in evaluating revegetation costs even when only
recent projects are used in the analysis, is that knowledge concerning re-
vegetation of lands disturbed by coal mining has increased so rapidly in the
last year or two that it is doubtful the same vegetation procedures would be
used on many of these projects today.
Based on a review of selected revegetation projects, either planned
in the near future or completed, it is estimated that revegetation costs per
acre should be between $350 and $400 depending upon soil treatment require-
ments, the type of revegetation and the use of mulch.
Use of Soil Tests and Factors Affecting Reclamation Decisions
Figure 1 shows an agricultural soil test report for a strip mine area
in Elk County, Pennsylvania made by Pennsylvania State University for
Michael Baker, Jr., Inc.' '). The area strip mined is approximately 15
acres. Three samples were submitted for soils analysis and each sample
was a composite of at least 15 samples collected throughout a portion of the
strip mine and quartered down to about a 1/2 pint size. The test results of
the samples are comparable and Figure 1 is representative of soil conditions,
The area was more or less graded after strip mining, but there are
no trees and it is barren except for occasional poverty grass, ferns and an
annual sage. Intermittent acid seepage occurs at several places and during
rainfall ponding occurs in some areas. Only minor grading is required in
areas gullied by erosion and to improve drainage. The strip mine is sur-
rounded by densely wooded land. The objective of reclamation, in this case,
-48-
-------
08/25/70
OATf
4533
LAI NO.
72874
SEklAlNO.
a iu u ±\.£j i
ELK
COUNTY
ACRES
7CC
FIELD
SOtl |
. SOIL TEST REPORT FOR:
MICHAEL BAKER JR INC
P 0 BOX 111
ROCHESTER PA
15074
THE PENNSYLVANIA STATE UNIVERSITY
SOIL & FORAGE TESTING LABORATORY
COLLEGE OF AGRICULTURE
UNIVERSITY PARK, PENNSYLVANIA 16802
• LABORATORY RESULTS;
3.9
pH
SOU.
5.4
PH
BUFFER
4
r
(Ita/A)
0.10
if
0.5
«9
(«|pr1Ng«.)
0.7
Co
17.4
CK
0.5
K
3.4
Me
% Saturation
4.3
Co
OTHER:
• SOIL NUTRIENT LEVELS:
PHOSPHORUS (P)
POTASSIUM (K)
CALCIUM (Ca)
MAGNESIUM (Mg)
LOW
MEDIUM
HIGH
EXCESSIVE
• LIMESTONE AND FERTILIZER RECOMMENDATIONS FOR ft SIDING OF LEGUME C'R
LEGUME-GRASS MIXTURE.
CALCULATED NUTRIENT REQUIREMENT IS 20-211-420 PER ACRE.
***FERT ILIZER-WORK IN DEEPLY 180 LBS OF PHOSPHATE PLUS 360 LBS CF POTASH
PER ACRE.
***FERTILIZER - DRILL 20-40-40 PER ACRE. BAND PLACE IF POSSIBLE.
***LIMESTONE-APPLY 14000 POUNDS OF STANDARD GROUND LIMESTONE CR
EQUIVALENT PER ACRE.
APPLY 240 LBS OF MAGNESIUM PER ACRE. IF RECOMMENDED AMOUNT WAS
APPLIED WITHIN THE LAST 12 MONTHS* NO ADDITIONAL MAGNESIUM IS NEEDED NOW.
SEE LEAFLET ST-2.
FOR OTHER CROPS, SEE LEAFLET ST-2, FERTILIZER TABLEt COLUMN 1
FERTILIZER APPLIED.
-49-
TOTAL COST/ACRE.
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-51-
-------
is to improve soil conditions so that a volunteer tree cover can be established.
This can best be accomplished by improving soil pH and establishing a ground
cover of grass and legume (creeping red fescue and birdsfoot trefoil).
The lime recommendation of 7 tons per acre shown on the Soil Test
Report will adjust the soil pH to 7. 0 In strip mine reclamation, a soil pH
adjustment of 6. 0 to 6. 5 should be sufficient, depending on the intended use
of the land. Therefore, in this example, an application of 6 tons of ground
limestone per acre was recommended. It was further recommended that one
half of the ground limestone requirement be spread and incorporated into the
soil to a minimum depth of 4 inches in the fall preceding spring planting so
the limestone would have time to react with the acid soil. One cause of seed-
ing failure is soil acidity, and failure may occur even though sufficient ground
limestone is applied at seeding time because the limestone does not have
enough time to react with the acid soil before germination.
Of significance in Figure 1 is the magnesium requirement of 240 Ibs.
per acre. In some areas soils are highly deficient in magnesium and this
requirement is often overlooked when it can be met with little or no additional
cost during revegetation. If the local limestone source produces a high cal-
cium limestone, the magnesium requirement can be met by blending one ton
of imported high magnesium, limestone per acre with local limestone. This
is probably the cheapest way but other magnesium materials such as Magox,
GranuMag and Alcan Magnesia can be used to satisfy this requirement.
The calculated nutrient requirement shown on Figure 1 is the amount
of nitrogen, phosphate and potash (N-P2O5-K2O) calculated by a standard
formula needed to support the yield goal of a crop, taking into consideration
the nutrients available in the soil and the requirements to maintain nutrient
level in the soil (Hinish, et al. ' '). Since this calculated nutrient require-
ment is for top agricultural production, the fertilizer amount can be reduced
by 1/4 to 1/3 for reclamation of lands disturbed by coal mining unless the
intended use is agricultural or grazing.
In most revegetation projects to date, fertilizers of the home garden
variety such as 10-10-10 and 5-10-10 have been used. These N-P2O5-K2O
standard ratios* of 1-1-1 and 1-2-2 do not appear to be indicative of nutrient
levels of "soil" found at many strip mine and refuse bank areas based on soil
test reports. A 1-4-4 standard ratio appears to be more applicable. In Fig-
ure 1, the calculated nutrient requirement of 20-211-420 can be satisfied by
using a 6-24-24 custom mix, therefore, 50-200-200 Ibs. N-P2O5-K2O was
recommended. Although the potash requirement is twice that of phosphate,
the latter is more significant since there is no crop yield and removal index
*At the request of the fertilizer industry, many states have agreed to restrict
fertilizer recommendations to a minimum of ratios . The calculated nutrient
requirement is adjusted to the "best fit" of one of twelve standard fertilizer
ratios .
-52-
-------
values for potash do not have to be considered. This is not the only recom-
mendation that would satisfy nutrient requirements. As an example a 5-10-10
or a 10-10-10 fertilizer could have been used along with 20 or 46% super phos-
phate. In addition to satisfying nutrient requirements, recommendations should
be based on cost and availability of fertilizer mixtures.
Bulk deliveries in tank trucks of blended fertilizer mixtures should be
considered because equivalent nutrient values can be obtained with a reduction
in trucking and material costs.
Green Thumb Program
Substantial savings in revegetation and in clearing and grubbing costs
may result if advantage is taken of the Green Thumb program' '. Green
Thumb is an Operation Mainstream program sponsored by the National Farm-
ers Union and funded by the U. S. Department of Labor. The program pro-
vides community improvement jobs for men 55 and older with farm or rural
backgrounds.
Crews of Green Thumbers are assigned to projects at the request of
local nonprofit organizations, both public and private. Local sponsors supply
materials, equipment and supervision in return for the manpower needed for
a particular project. There is no red tape, no bookkeeping and no cash con-
tributions. The crews remain on the Green Thumb payroll and all agreements
are informal.
The program was started in 1966 and many crews are working in Appa-
lachia. They have worked at developing state parks, highway beautification
and development of roadside parks.
In the Monongahela river Basin, the program is presently operating in
Pennsylvania. For information contact:
Pennsylvania Farmers Union Green Thumb
240 N. 3rd Street, Room 1106
Payne-Shoemaker Building
Harrisburg, Pennsylvania 17100
Requests for expanding Green Thumb into states where there is now no
program should be addressed to:
U. S. Department of Labor
Manpower Administration
Division of Work Experience
1741 Rhode Island Avenue, N. W.
Washington, D. C. 20210
-53-
-------
REFERENCES
1. U. S. Dept. of Agriculture, 1968, Restoring Surface Mined Land: Misc.
Publ. No. 1082, 18 p. (BCR 68-162)
2. U. S. Dept. Of Interior, 1967, Surface Mining and Our Environment, A
Special Report to the Nation: 124 p. (BCR 67-82)
3. Struthers, P. H. and Vimmerstedt, J. P., 1965, Advances in Strip Mine
Reclamation: Ohio Rept. on Res. and Development, jj£(l), p. 8-9
(BCR 65-26)
4. Hill, Ronald D. , 1969, Reclamation and Revegetation of 640 Acres of Sur-
face Mines, Elkins, West Virginia: Int. Sym. Ecology Revegetation of
Drastically Disturbed Areas, University Park, Pa. State Univ., 47 p.
(BCR 69-53)
5. Czapowskyj, M. M. and McQuilkin, W. E. , 1966, Survival and Early
Growth of Planted Forest Trees on Strip-Mine Spoils in the Anthracite
Region: U.S. Forest Service, Res. Paper NE-46, 29 p. (No BCR No.)
6. Mellinger, R. H. , I960, Results of Revegetation of Strip Mine Spoil by
Soil Conservation Districts in West Virginia: W. Va. Univ. Agr. Exp.
Sta. Bull. No. 540, 18 p. (No BCR No. )
7. Smith, R. M. , Tryon, E. H. and Tyner, E. H. , 1971, Soil Development
on Mine Spoil: W. Va. Univ. Agr. Exp. Sta. Bull. 640T, 47 p. (No BCR
No. )
8. Truax-Traer Coal Company, 1971, Control of Mine Drainage from Coal
Mine Mineral Wastes: Environmental Protection Agency, Water Quality
Office, Res. Ser. 14010 DDK 08/71, 148 p. (BCR 71-69)
9. Tyner, E. H. and Smith, R. M. , 1945, The Reclamation of the Strip-
Mined Coal Lands of West Virginia with Forage Species: Soil Sci. Soc.
Am. Proc. _10_, p. 429-36 (No BCR No.)
10. Capp, J. P. and Adams, L. M. , 1971, Reclamation of Coal Mine Waters
and Strip Spoil with Fly Ash: Am. Chem. Soc. Div. Fuel. Chem. Preprints
_l_5 (2), p. 26-37 (BCR 71-31)
11. Magnuson, M. O. and Kimball, R. L., 1968, Revegetation Studies at Three
Strip-Mine Sites in North-Central Pennsylvania: U. S. Bur. Mines Rept.
Inv. 7075, 8 p. (No BCR No.)
12. Berg, W. A., 1965, Plant-Toxic Chemicals in Acid Spoils: Coal Mine
Spoil Reclamation Sym. Proc., Pa. State Univ., p. 91-93 (No BCR No.)
-54-
-------
13. Berg, W. A. and Vogel, W. G., 1971, Aluminum and Manganese Toxicities
of Plants Grown in Acid Coal Mine Spoils:
14. Beyer, L. E. and Hutnik, R. J. , 1969, Acid and Aluminum Toxicity as
Related to Strip-Mine Spoil Banks In Western Pennsylvania: Pa. State
Univ., Spec. Res. Rept. SR-72, 94 p. (BCR 69-34)
15. Coleman, N. T. , Kamprath, E. J. , and Weed, S. B. , 1958, Liming:
Advance. Agron. 10, p. 475-522
16. Cummins, D. G. , Plass, W. T. and Gentry, C. E. , 1965, Chemical and
Physical Properties of Spoil Banks in Eastern Kentucky Coal Fields: U. S.
Forest Service, Res. Rept. CS-17, lip. (No BCR No. )
17. Hart, G. and Byrnes, W. R., I960, Trees for Strip-Mined Lands, A
Report on 10-Year Survival and Growth of Trees Planted on Coal-Stripped
Lands in Pennsylvania's Bituminous Region: U. S. Forest Service, 136 p.
(No BCR No.)
18. Struthers, P. H. , 1964, Chemical Weathering of Strip-Mine Spoils: Ohio
Jour. Sci. 64 (2), p. 125-31 (BCR 64-34)
19. Maguire, W. P., 1955, Radiation, Surface Temperature, and Seedling
Survival: Forest Sci. j_, p. 277-85
20. Marx, D. H. and Bryan, W. C. , 1971, Influence of Ectomycorrhizae on
Survival and Growth of Aseptic Seedlings of Loblolly Pine at High Tem-
peratures: Forest Sci. 17, p. 37-41
21. Nicholes, A. K. and Hutnik, R. J. , 1971, Ectomycorrhizal Establishment
and Seedling Response on Variously Treated Deep-Mine Coal Refuse: Pa.
State Univ., Spec. Res. Report SR-89, 121 p. (No BCR No.)
22. Sullivan, D. C,, 1967, Current Research Trends in Mined-Land Conser-
vation and Utilization: Am. Inst. Mining Eng. Preprint No. 67F65, 18 p.
(BCR 67-11)
23. Limstrom, G. A. and Marz, R. W. , 1949, Rehabilitation of Lands Stripped
for Coal in Ohio: U. S. Forest Service, Central States Forest Exp. Sta.
Tech. Paper No. 113, 41 p. (BCR 40-56)
24. Paton, R. R. , et al. , Tree Planting Guide for the Reclamation of Strip
Mine Lands in Ohio: Ohio Reclamation Assoc. , Tech. Bull. No. 70-1,
21 p. (BCR 70-40)
-55-
-------
25. Grube, W. E. , Jr., et al. , 1971, Mine Spoil Potentials for Water Quality
Controlled Erosion: Environmental Protection Agency, Water Quality
Office, Res. Ser. 14010 EJE 12/71, 206 p. (BCR 71-72)
26. Krause, R. R., 1972, Mining and Reclamation Techniques to Control
Mine Drainage; Fourth Sym. Coal Mine Drainage Res. Preprints, Pitts-
burgh, p. 425-30 (BCR 72-
27. Scott, R. B., Hill, R. D. and Wilmoth, R. C. , 1970, Cost of Reclamation
and Mine Drainage Abatement - Elkins Demonstration Project: Am. Inst.
Mining Eng. , Soc. Mining Eng. Fall Meeting, St. Louis, Preprint No.
70-AG-349, 22 p. (BCR 70-70)
28. Grim, Elmore C., 1972, Personal Communication Compiled by Mr. Grim,
Surface Mining Specialist, Environmental Protection Agency, National
Research Center, Cincinnati
29. Michael Baker, Jr., Inc., 1970, Acid Mine Drainage Survey - East Branch
Clarion River Watershed, Elk and McKean Counties: Rept. to Pa. Dept.
Mines Mineral Ind. , Project SL-108, 379 p. (BCR 70-113)
30. Hinish, W. W. , Heddleson, M. R. and Eakin, J. H., Jr., , Soil
Testing Handbook: Pa. State Univ., College of Agruculture, 30 p., forms,
written for County Agricultural Extension Agents
31. Appalachia, 1972, Green Thumb in Appalachia Provides Employment for
the Elderly: 5. (5), p. 1-6.
-56-
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MINE SEALING
TABLE OF CONTENTS
Page No.
Introduction 61
Hydraulic Mine Seals 63
Grouted Double Bulkhead Seal 65
Grouted Single Bulkhead Seals and Curtain Grouting 71
Review of Unit Bid Prices for Three Hydraulic Mine
Sealing Projects 76
Hydraulic Sealing of Accessible Mine Headings 80
Quick Setting Double Bulkhead Seal (No. 1) 80
Quick Setting Double Bulkhead Seal (No. 2) 82
Quick Setting Single Bulkhead Seal 82
Expandable Grout Retainer Seal 86
Grouted Limestone Aggregate Seal 89
Reinforced Concrete Hydraulic Seal 89
Summary of Costs for Sealing Accessible Mine Openings 94
Estimated Cost for Grouted Double Bulkhead Seal 95
Factors Affecting Cost of Hydraulic Mine Seals 95
Limestone Barrier Mine Seals (Permeable Plug) 96
Dry Mine Seals 99
Air Mine Seals 100
Summary of Costs for Dry and Air Mine Seals 105
References 106
-57-
-------
LIST OF TABLES
Page No.
1. Cost Tabulation - Deep Mine Seals, Moraine State Park 68
2. Cost Tabulation - Deep Mine Seals, Slippery Rock Creek 70
3. Cost Tabulation - Pressure Curtain Grouting,
Thomas Mills Area 75
4. Unit Bid Prices - Deep Mine Seals, Moraine State Park 77
5. Unit Bid Prices - Deep Mine Seals, Slippery Rock Creek 78
6. Unit Bid Prices - Pressure Curtain Grouting and Reclamation,
Thomas Mills Area 79
7. Cost Data - Grouted Aggregate Seals, Harrison County,
West Virginia 91
LIST OF FIGURES
1. Isometric Drawing of Grouted Double Bulkhead Seal 66
2. Construction Drawing of Grouted Double Bulkhead Seal 67
3. Plan View - Portion of Thomas Mills Mine Area 72
4. Design of Single Bulkhead Mine Seal 73
5. Quick Setting Double Bulkhead Seal - Mine No. 62-008 81
6. Quick Setting Double Bulkhead Seal - Mine No. RT5-2 83
7. Plan View of Remedial Construction - Mine No. RT5-2 84
8. Quick Setting Single Bulkhead Seal - Mine No. 62-008 85
9. Expendable Grout Retainer Seal - Mine No. 14-042A 87
10. Expendable Grout Retainer Seal Following Remedial
Work - Mine No. 14-042A 88
11. Grouted Limestone Aggregate Seal - Mine No. 40-016 90
12. Plan View of Reinforced Concrete Hydraulic Seal -
Essen Mine No. 2 92
-58-
-------
Page No.
13. Section of Reinforced Concrete Hydraulic Seal -
Essen Mine No. 2 93
14. Limestone Barrier Mine Seal (Permeable Plug) -
Mine No. RT5-2 98
15. General Arrangement of an Air Seal 102
16. Average Monthly Total Acidity and Flow Rate of the
Mine Effluent - Air Sealed Mine in Pennsylvania 104
-59-
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-------
MINE SEALING
INTRODUCTION
Mine sealing has been defined as the closure of mine entries, drifts,
slopes, shafts, subsidence holes, fractures and other openings into under-
ground mines with clay, earth, rock, timber, concrete blocks, brick, steel,
concrete, fly ash, grout and other suitable materials (Foreman^•*•)),
/
Mine seals can be classified into three general types based on function
and method of construction which to a certain extent is the result of geohydro-
logical conditions. The three types and their functions are:
1. Dry Seal - The function of a dry seal is to prevent air and water from
entering the mine. This type of seal is constructed at openings which do
not have a discharge or the discharge is so slight there is little danger
of a hydraulic head developing.
2. Air Seal - An air seal is designed to exclude air from entering a mine but
it permits the normal water flow from the mine to be discharged. The air
seal is designed with a water trap and the principle is similar to the way
water traps in sinks and drains function.
3. Hydraulic Seal - A hydraulic seal is constructed at a mine with a discharge
to prevent water flow from the mine. A hydraulic head is created which
floods the mine and air is excluded by inundation.
Although acid mine drainage discharges from deep mines has been a
significant pollution problem for over a century, any mine sealing work prior
to the 1930's generally was performed as a safety precaution and not to reduce
acid discharges. The concept of sealing coal mines as a means of reducing
acidity was the subject of discussion in several technical papers in the 1920's
and early 1930's. The U.S. Bureau of Mines performed much of the early re-
search and an experimental mine sealing program was started in 1932 in which
three mines were sealed with a water trap designed to exclude air from enter-
ing the mine but permitting the normal flow of water at the discharge (Air Seals).
An analysis of water samples collected from the mines over a period of a year
indicated a decrease in acidity of the discharges.
A large mine sealing program was started in Pennsylvania and West
Virginia in 1933 as a result of these studies. The mine sealing work was per-
formed under the Works Progress Administration and the Civil Works Admini-
stration. The effectiveness of the programs in reducing acid discharges has
been questioned by some, but Maize' ' indicates acid discharges were reduced
in some Pennsylvania streams to the extent that fish life appeared and the water
could be used for industrial and domestic purposes. The U.S. Public Health
Service^) estimated a 28 percent reduction in acid loading in the Ohio River as
as result of the abandoned mine sealing programs. However, the work performed
-61-
-------
in many areas was not adequate to exclude air from the underground workings
and some mine seals failed after several years. In other areas, the acid
water found new discharge openings.
Pennsylvania in 1935 passed The Bituminous Mining Law, Act No. 55,
which provided for sealing of abandoned mines by the Pennsylvania Department
of Mines. Section 1 of the Act stated "That it shall be the duty of each and
every owner, operator, or lessee of any abandoned bituminous coal mine or
abandoned working, which is discharging polluted water which flows into any
of the streams or rivers of this Commonwealth, or which is in danger of being
set afire, to shoot down, or cause to be shot down, or otherwise seal, or cause
to be sealed, the entries and air shafts of such abandoned coal mine or working
for the purpose of cutting off the supply of air from the abandoned mine or work-
ing. " Mine sealing was continued under this Act by the Pennsylvania Department
of Mines until 1947 when a law was passed by the State Legislature establishing
a Mine Sealing Bureau within the Department of Mines. Over 2.5 million dollars
was appropriated for mine sealing under this program between 1947 and 1949.
The first mine sealing performed by the new Bureau was in the watershed
of the Casselman River, a tributary of the Youghiogheny River. According to
Maize^) this stream was highly polluted with acid mine drainage, but five years
later the Casselman River was alkaline and supported fish. Maize also states
that water analyses of the Youghiogheny River in 1937 at a point just before it
enters the MonongahelaRiver showed the stream was carrying 870 tons of acid
per day. In 1950 a water sample taken at the same place indicated the acid load
to be 185 tons per day. As a result of this reduction in acid, the City of
McKeesport again began taking its domestic water supply from the Youghiogheny
River(^)> The mine sealing work under the program consisted of dry and air
seals, filling of cracks, subsidence areas, slopes and shafts, and also a limited
amount of drainage diversion.
The very encouraging results obtained with dry and air seals in the Cassel-
man River watershed and other areas in Pennsylvania as reported by Maize^'
contrasts sharply with the negative results reported by others, such as the recent
Elkins, West Virginia demonstration project' ' and the study by BraleyV^' reported
in 1962. Braley indicated air sealing did not substantially reduce the oxygen con-
tent of the mine atmosphere and implied that mine sealing of abandoned drift mines
above drainage is ineffective in reducing the quantity of acid discharged. No
study has been made to determine why air sealing methods appear to be effective
in some areas and not in others. A study of this type may be rewarding because
air seals are less expensive to construct than hydraulic seals. It may be difficult
to interpret results of a study of this type because active mining operations con-
tinue to the present in many of the watersheds where air seals were constructed
and it appears the amount of acid discharged has increased yearly because of
this later mining. The Casselman River watershed is an example of an area
where the effects of an active air and dry mine sealing program was negated by
later mining operations.
-62-
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Mine sealing research continued in the 1950's and 1960's with studies
being made by Bituminous Coal Research, Inc., Mellon Institute, U.S. Bureau
of Mines and several universities and State agencies. The Ohio River Valley
Sanitation Commission (ORSANCO) adopted Resolution No. 5-60 in I960, amen-
ded 1963, which in part stated "Upon discontinuance of operations of any mine
all practicable mine-closing measures consistent with safety requirements,
shall be employed to minimize the formation and discharge of acid mine-drainage"
The coal industry in the Ohio River watershed is required to carry out provisions
of ORSANCO Resolution 5-60. An explanation of the measures approved in the
Resolution was published in 1964\") and it was recommended where practical
hydraulic mine seals should be constructed because mine sealing is not effective
in preventing acid mine drainage unless the coal seam and other acid producing
strata and materials are submerged.
Until recently most seals constructed at mine portals were air seals.
New developments in mine sealing techniques including methods of hydraulic
sealing are a result of increased interest in the field of environmental control.
From 1966 through 1969, the Halliburton Company' ' had a contract with the
Federal Water Pollution Control Administration, now Environmental Protection
Agency, to develop and field test new concepts for watertight or hydraulic seals.
Moebs and Krickovic(^) reported in 1970 on a U.S. Bureau of Mines air sealing
project of an above drainage coal mine. A comparison of the chemical analyses
of the mine effluent during the two year, seven month period before sealing and
during the two year, eight month period after sealing showed that the acid load
had been reduced.
Since 1969 most of the seals constructed at deep mine portals in Pennsyl-
vania have been hydraulic mine seals. Grouted double bulkhead seals were de-
veloped in Pennsylvania for the Moraine State Park and Slippery Rock Creek
projects and a grouted single bulkhead seal was designed for the Thomas Mills
mine area. This extensive hydraulic mine sealing effort is part of "Operation
Scarlift, " Pennsylvania's 500 million dollar bond issue for a Land and Water
Conservation and Reclamation Fund.
HYDRAULIC MINE SEALS
The objective of hydraulic or watertight mine seals is to exclude air
from the mine by flooding mine workings. Watertight bulkheads in mine open-
ings must be capable of withstanding the maximum anticipated hydrostatic head.
Installation of hydraulic mine seals includes sealing of all drifts, slopes, shafts,
subsidence areas and adjacent strata that can affect the integrity of the water-
tight seal.
Properly designed and constructed hydraulic mine seals will reduce the
rate at which oxygen is supplied for pyrite oxidation in the mines. Theoretically,
by flooding the mine with water, atmospheric oxygen will not be available for
acid producing chemical reactions. Oxygen, however, can be supplied at a re-
duced rate through the following mechanisms:
-63-
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1. Water percolating downward through the overlying strata contains dissolved
oxygen, usually 10 to 14 mg/1.
2. Groundwater containing dissolved oxygen may move through the mine en-
vironment.
3. Oxygen in void spaces above the water table may dissolve and diffuse down-
ward to react with pyrite in the mine environment.
Any or all of these mechanisms can operate to yield acid mine waters
within sealed mines or in unsealed abandoned mines advanced down dip which
are now flooded. However, since less oxygen is available for chemical re-
actions, less acid should be produced in a given time. In some cases sufficient
carbonate minerals may be present in the mine environment to neutralize the
smaller amount of acid produced or alkaline groundwater flow through the mine
environment may result in neutralization of acid.
Hydraulic mine sealing construction methods are divided into two general
classifications:
1. Accessible Hydraulic Mine Sealing - The mine openings are open from the
portal to the construction area or can be opened with minor effort. The
seals are constructed from within the mines. This type of sealing has the
advantage of visual inspection during construction and should afford a great-
er degree of success.
2. Inaccessible Hydraulic Mine Sealing - The mine openings are caved at the
portal and cannot be reopened for mine sealing unless there is a large ex-
penditure for preparation and safety. In this case, mine sealing must be
accomplished from above ground by drilling holes for placement of bulkhead
materials and for grouting techniques. Since there is no opportunity for
visual inspection other than a borehole camera, exploratory and obser-
vation borings may be required.
A substantial number of abandoned mines within the Monongahela River
Basin can be classified as inaccessible. Abandoned mines can be expected to
have fracturing of adjacent strata due to the lack of mine support and relief
stresses. The strata adjacent to the mine usually has to be grouted to insure
a watertight seal.
Within the last few years, several methods of constructing hydraulic
seals have been tested and other designs are proposed for future projects.
With the exception of the grouted double bulkhead seal, which has been used
extensively in Pennsylvania on the Moraine State Park and Slippery Rock Creek
projects, most hydraulic seal methods have only been tested experimentally on
demonstration projects.
-64-
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The following hydraulic mine sealing methods are discussed:
Inaccessible Hydraulic Mine Sealing Methods
1. Grouted double bulkhead seal,
2. Grouted single bulkhead seal.
Accessible Hydraulic Mine Sealing Methods
1. Quick setting double bulkhead seal.
2. Quick setting single bulkhead seal.
3. Expendible grout retainer seal.
4. Grouted (horizontally) aggregate seal.
5. Reinforced concrete seal.
Grouted Double Bulkhead Seal
The grouted double bulkhead method of sealing inaccessible mines was
developed for use at Moraine State Park, Butler County, Pennsylvania. This
project was one of the first to be constructed under "Operation Scarlift, "
Pennsylvania's 500 million dollar bond issue for a Land and Water Conservation
and Reclamation Fund.
A total of 69 hydraulic seals were installed in drift mines which were
advanced up dip. It is the most extensive use of this type of seal to date. The
design of the double bulkhead hydraulic seal is shown on Figures 1 and 2.
The engineering survey of the Moraine State Park Watershed Area rec-
ommended hydraulic sealing of 60 mines at an estimated cost of $15, 000 per
seal (Gwin Engineers, Inc.v')). A contract was awarded in 1969 for sealing
53 of these mines. While work was in progress, the Pennsylvania Department
of Mines and Mineral Industries, now Department of Environmental Resources,
recommended the sealing of an additional 20 mines. It was later discovered,
through exploratory drilling, that some of the depressions were natural and not
caved mine headings, therefore, only 69 mine seals were constructed. Curtain
grouting of adjacent strata was extended a minimum of 50 feet on both sides of
a mine entry.
Table 1 is a cost tabulation showing estimated contract quantities for
various items of construction, unit bid prices, actual quantities required, and
actual cost. The unit cost for Item 1, Mine Sealing, includes all the work needed
for construction of grouted double bulkhead seals, such as placing front and rear
coarse aggregate bulkheads, grouting of bulkheads, pumping of water from cavity
between bulkheads and grouting of center plug.
-65-
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-66-
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FIGURE 2
Bulkhead Drill Holes 6"dia on 30'Centers
With Alignment Across The Main Entry. Drill
Holes To Be Extended Into Coal Ribs As Shown.
Observation
a/or Pump
Drill
Hole 6"dia
Core Drill Hotes As-
Directed By The Engineer
Injection Holes For Center Plug Area,Location And
Number of Holes Dependent on Conditions.This
Drawing Shows The Win. Number of Holes.
Additional Holes May Be Required.
Grout Curtain Holes 3"dia.0n 10'Centers On
Alignment Parallel To SApprox.Halfway Between
Front and Rear Bukhead Drill Hotes. Minimum Of
50'0n Both Sides Of The Mine Entry.
/Observation And/or
Pump Drill Hole
Location To Be
Determined In Field
PLAN
Distance Between Front And Rear Bulkhead Alignment
_Range20'to25'As Directed By The Engineer
/CoreDrill Hole And
Injection Hole
Alignment
'REAR
COURSE
CONCRETE
CENTER i., PLUG
AGGREGATE
FRONT i
COURSE UlAGGREGATE
PROFILE
CONSTRUCTION DRAWING OF GROUTED DOUBLE BULKHEAD SEAL
After Foreman, 1970
(10)
-67-
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-68-
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An analysis of the cost tabulation in Table 1 shows that based on estimated
quantities and unit bid prices the average estimated cost per seal is $15,Z39.04
for 73 seals. Using the original base bid for 53 seals, the average estimated
cost per seal is $16, 364. 15. The actual cost per seal for the 69 completed seals
was $19,588.73. The cost per seal includes curtain grouting and air shaft seal-
ing. Air shaft sealing was a minor item, but curtain grouting was a major factor
in increasing the cost per mine seal and the actual quantities shown on Table 1
greatly exceed the original estimates.
The costs of individual seals ranged from $8, 300 to $58, 000. The esti-
mating of quantities of materials for inaccessible mine sealing is difficult, par-
ticularly the quantities needed for curtain grouting. In most cases, the existing
subsurface conditions cannot be determined with any degree of certainty for
quantity estimates unless there is an extensive and costly subsurface investiga-
tion. The cost of this investigation would only add to the overall cost of recla-
mation. A limite.d subsurface investigation is necessary, though, to obtain
information on the probable hydrostatic head and the general character of the
rock to be grouted. Grouting estimates should be on the conservative side.
Curtain grouting, Item 3 in Table 1, represented 60.6 percent of the
total cost of the Moraine State Park Project and it is estimated the cost per
lineal foot of grout curtain was $80. 00.
Curtain Grouting Costs - Item 3
Estimated
Contract Cost Actual Costs
Item3 $517,750.00 $819,745.60
% Total Cost 46.5 60.6
Cost L.F. /Drilled 7.33 8.17
Cost L.F. /Curtain 51.76 80.00 (Estimate)
The grouted double bulkhead mine sealing program at Moraine State Park
was successful in reducing acid discharges. The reduction in pounds of acid was
estimated to be 76 percent in December, 1969 and continued observation accord-
ing to Foreman! H) indicates the reduction in pounds of acid is 68 percent as of
January, 1972.
The second most extensive hydraulic mine sealing project to date has
been sealing of abandoned drift mines in the Argentine and Whiskerville areas
in Slippery Rock Creek drainage basin(H). The project is currently nearing
completion and it is one of Pennsylvania's many "Operation Scar lift" projects.
The cost tabulation for this project is presented in Table 2.
-69-
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-70-
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The design of the double bulkhead hydraulic seals is the same as those
constructed at Moraine State Park except that grouting of aggregate bulkheads
before placement of the center plug was deleted from the contract. This change
order was the result of a law suit brought by Layne-New York Company, Inc. ,
for alleged damages arising out of patent infringement. Layne-New York Com-
pany, Inc. (^2) is claiming sole ownership in United States Patent No. 3,469,405
of the concept covering design and placement by grouting methods of double bulk-
head seals. The Commonwealth of Pennsylvania is challenging this claim. Al-
though, it is believed the law suit had no affect on the bid prices for this project,
it is difficult to determine what affect it will have on future bids for this type seal.
The physiography and geology in the Argentine and Whiskerville area and
in the Moraine State Park area are similar. Bidding was based on an estimated
34 mine seals. Only 29 mine headings were believed to require sealing, but an
additional five were estimated in case others were found during construction.
Actually, only 24 seals were constructed because five of the locations were proved
by exploratory drilling to be natural depressions and not caved headings. Even
though less seals are being constructed, actual project cost will approach esti-
mated total cost because curtain grouting quantities are higher than estimated.
Final cost figures are not available, but it is estimated the average cost
per seal, including curtain grouting, will be $18, 330. 00, or 32. 8% over the con-
tract estimated cost. The cost per individual seal will be dependent upon the ex-
tent of required curtain grouting. It is estimated the minimum cost per seal will
be approximately $7, 500 and the maximum cost $40, 000.
Grouted Single Bulkhead Seals and Curtain Grouting
Mine sealing and curtain grouting work is currently being performed in
the Thomas Mills Mine Area, Somerset County, Pennsylvania (Operation Scar-
lift Project, No. SL 151-1). This project is under the supervision of the Penn-
sylvania Department of Environmental Resources and a plan of part of the mine
area is shown in Figure 3.
The work in progress involves placement of a continuous grout curtain,
2,200 feet in length, with construction of single grouted aggregate bulkhead bar-
riers or seals whenever mine rooms or passage ways are encountered.
The design of this type seal is shown on Figure 4. The barriers are
being constructed by injecting Pennsylvania Department of Transportation
Specification 2B coarse aggregate into bore holes spaced on two foot centers.
The aggregate is spread by mechanical methods such as tamping, vibrating a
and/or flushing until a cone of material is built up to the headwall of the mine.
The barriers are then pressure grouted, through metal pipes extending into
the aggregate, using a cement fly ash slurry or a cement fly ash slurry with
bentonite or AM 9 admixture to form the hydraulic seal.
-71-
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FIGURE 3
PLAN VIEW
PORTION OF THOMAS MILLS MINE AREA
Somerset County, Pennsylvonio
Source1 Pennsylvania Department of Environmental Resources^
Scale: I" = 100'
•72-
-------
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-73-
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The cost tabulation of unit prices is presented in Table 3 and it is
anticipated the contract price will be exceeded, perhaps greatly, because
more mine voids are being encountered than originally expected. The voids
will require additional grouted aggregate mine seals. The nonavailability
of sufficiently detailed mine maps is considered the main factor in under-
estimating material quantities. Also of significance, is the fact that unit
prices for cement, fly ash and bentonite admixture are substantially above
engineering estimates. The unit price for these items includes material
cost, transportation, storage, and labor associated with the mixing and
grouting operations. The unit cost of $9. 00/ton for fly ash appears reason-
able considering prices for other similar projects and indicates an under-
estimate by the engineer. The unit price for concrete at $10.00/sack and
bentonite at $1.00/lb. appears very high.
By applying contract unit prices to a mine void five (5) feet in height,
twelve (12) feet in width, and at a depth of 50 feet, the approximate cost for
construction of a grouted seal would be $2, 100 as follows:
Item Quantity Unit Price Cost
Drill holes (8)
Cement for grouting
Fly ash for grouting
424 L.F.
35 Sacks
3.9 Tons
Bentonite for grouting 200 Ibs.
#2B Stone
30 Tons
$ 2.10
10.00
9.00
1. 00
9.75
Total
Call
$ 890.40
350.00
351. 00
200. 00
292.50
$2, 083. 90
$2, 100.00
If the strata is curtain grouted for 50 feet on both sides of the seal, the
approximate cost would be $2, 000 as follows:
Item
Drill holes (10)
Curtain grouting
materials
Quantity Unit Price Cost
530 L.F. $ 2. 10 $1, 113.00
(assume same quantities 901. 00
as above, except 2B Stone)
Total
$2,014.00
Increasing the above costs by 10% to cover mobilization and demobili-
zation, the total cost, including curtain grouting, should be about $4, 500.
-74-
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price will be exceede
-75-
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Review of Unit Bid Prices for Three Hydraulic Mine Sealing Projects
Tables 4, 5 and 6 show the unit prices bid by contractors on the
following projects:
1. Moraine State Park, Butler County, Pennsylvania
Operation Scar lift Project SL 105-3
2. Slippery Rock Creek, Argentine and Whiskerville Areas,
Butler County, Pennsylvania
Operation Scarlift Project SL 110-1BD
3. Thomas Mills Area, Somerset County, Pennsylvania
Operation Scarlift Project SL 151-1
The range in unit bid prices, particularly grouting materials, indi-
cates this could be a major factor in cost overruns. For example: fly ash -
$9. 00 to $96. 00/ton; bentonite - $0. 10 to $1. 50/lb. ; No. 2 Stone - $6. 00 to
$24. 00/ton; sand - $5. 80 to $50. 00/ton and cement - $3. 00 to $10. 00/sack.
When larger quantities of material are used than anticipated in design, and
the unit bid price for the item is high, large cost overruns are bound to occur.
It is suggested that in preparing bid proposals, maximum quantities be esti-
mated. This would, to a certain extent, prevent contractors from capitaliz-
ing on the fact that quantities are underestimated.
Contractors are in business to make money, and a contractor in order
to survive must take advantage of every opportunity to make a legitimate pro-
fit, even a very large one, if he is to offset projects which showed a loss or
only a marginal profit. An experienced contractor many times can tell when
quantities are underestimated and he will balance his unit price bids to make
the most profit and at the same time attempt to come up with an overall low
bid for the project. State and federal agencies on occasion are guilty of the
practice of underestimating the cost of a project, either because of false op-
timism and the desire to get a project started, or because of an intentional
underestimate in order to get a project approved within a limited budget,
knowing full well that additional funds will be appropriated at a later date to
complete the project.
-76-
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-79-
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Hydraulic Sealing of Accessible Mine Headings
The work performed in hydraulic sealing of accessible mine headings
is limited. The Halliburton CompanyC?) under contract to the Environmental
Protection Agency has developed several methods and techniques for hydraulic
sealing of accessible mines. The demonstration projects were performed at
mine openings in Harrison County, West Virginia from 1967 to 1969. The fol-
lowing is a description of some of the hydraulic seals constructed under this
program.
Quick Setting Double Bulkhead Seal
Mine No. 62-008, Opening No. 5
As a result of a series of laboratory and field tests on the applicability
of quick setting slurries, this site was chosen for construction of a quick set-
ting double bulkhead seal. A drawing of a section through the seal is presented
in Figure 5.
The slurry used for construction of the bulkhead was a blend of two sep-
arate slurries which were mixed immediately before being pumped into the mine.
The blended slurry consisted of equal parts of the following:
Slurry No. 1 Slurry No. 2
Water 870 gallons Water 1,050 gallons
Cement 180 sacks Bentonite 700 pounds
Sodium Silicate 350 gallons
The void between the bulkheads was filled by pumping Halliburton
LIGHT Cement, through a grout pipe. This grouting material is a blend of
65% portland cement, 35% fly ash and 6% bentonite with 9.9 gallons of water
per bulk cubic foot of dry material, or 61 parts cement, 26 parts fly ash,
5.2 parts bentonite and 82.5 parts water by weight.
The mine sealing is considered to be completely successful as all
flow from the mine at this heading was stopped. The construction cost of
the seal was $9, 449. 00 based on the following breakdown of costs:
Item Cost
Site Preparation $ 894.00
Grouting Materials 3, 872. 00
Equipment and Operators 4, 683. 00
Total $9,449.00
-80-
-------
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Quick Setting Double Bulkhead Seal
Mine RT 5-2, Seal No. 1
The construction details of this mine sealing project are shown in Fig-
ures 6 and 7. A quick setting slurry was used for construction of the bulkheads
as in Mine No. 62-008. After construction of the rear bulkhead, a center plug
was constructed by pneumatic placement of limestone aggregate. This aggre-
gate was grouted with a cement-fly ash-bentonite mixture (Halliburton LIGHT
Cement) after placement of the front bulkhead. Grouting of the mixture was con-
tinuous until a fill-up was obtained to within a few inches of the roof. At that
time, leaks appeared around the top corners of the front bulkhead, so the slurry
was altered by adding shredded cellophane, sawdust and shredded cane fiber.
This material successfully closed the leaks.
The total construction cost for the seal, including the site preparation
cost of $1, 079. 00, was $9, 463. 00 for materials and equipment.
The purpose of the project was to develop methods of remote grouting
application for use in mine drifts having high water discharge rates. The water
flow from the mine opening prior to construction of the seal was in excess of 50
gallons per minute. The seal appears to be effective in preventing water flow
from the opening, but when the head of water impounded behind the seal increased,
the pressure caused a substantial leakage from an unknown adjacent opening.
Remedial work on the second opening, Seal No. 2, was accomplished by con-
structing a bulkhead of graded aggregate and agricultural lime; this work is dis-
cussed under "Limestone Barrier Mine Sealing."
Quick Setting Single Bulkhead Seal
Mine No. 62-008, Opening No. 4
The single bulkhead seal was constructed using the same slurry mixture
as used in constructing the double bulkhead seal at Opening No. 5 of the same
mine. Figure 8 is a drawing of a section through the bulkhead. The mine seal-
ing appears to be successful since only a slight seepage occurred with a hy-
draulic head of 54.4 inches. The total construction cost was $3,564.00 as fol-
lows:
Item Cost
Site Preparation $ 647.00
Grouting Materials 1,165.00
Equipment and Operators 1, 752. 00
Total $3,564.00
-82-
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PLAN
/
• FRONT
BULKHEAD,
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REAR
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SECTION A-A
CONSTRUCTION DETAIL
SEAL NO. I - MINE NO. RT5-2
FIGURE 6
From Halliburton Co.
(7)
-83-
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Expendable Grout Retainer Seal
Mine No. 14-042A
An abandoned mine near Clarksburg, West Virginia was selected for
application of a mine seal because of its remote location, small but easily
accessible area and highly acid discharge. The seal was constructed by
placing successive layers of expandable nylon and cotton cloth grout retain-
ers and filling them with a cement grout slurry to conform to the shape of
the opening. Figure 9 is a drawing of the seal showing the installation and
mine configuration.
After the mine seal was installed, a reduction of 92 percent in the
discharge was observed, but cumulative leakage from small leaks in the coal
surfaces around the seal amounted to about 1.5 gallons per minute. Grout-
ing around the grout retainers with Halliburton PWG grout fluid, an acryla-
mide monomeric solution, reduced the leakage to 0.33 gallons per minute.
Grouting was discontinued because it appeared the remaining leakage was
coming from coal fractures several feet from the seal.
An attempt was made to further reduce the leakage by injecting a
gelling agent into the mine behind the seal. The gelling material would flow
into leakage points from inside the mine. The gelling material consisted of
bentonite, shredded cane fiber (Fibertex) and fresh water. At the start of
this remedial work the flow rate from the mine was 0.40 gallons per minute.
A total of 41, 200 gallons of gelled fluid was pumped into the mine over a four
day period utilizing 30, 000 pounds of Wyoming bentonite and 295 pounds of
Fibertex. Figure 10 is a schematic drawing of the mine to show the condition
following remedial work.
The flow rate at completion was 0.55 gallons per minute, an increase
of 0. 15 gallons over the initial rate. The leakage has continued to average
0. 5 gallons per minute since treatment, therefore, the treatment did not
accomplish desired results.
Construction costs were not available for the grout retainer seal and
Halliburton PWG grout fluid treatment 14). The following construction costs
were incurred for remedial work using the gelling material for treatment:
Item Cost
Access Rights $ 300. 00
Materials and Equipment 2,771.00
Site Restoration 279.00
Total $3,350.00
-86-
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Grouted Limestone Aggregate Seal
Mine No. 40-016. 2 Openings
This small abandoned mine south of Clarksburg, West Virginia had a
moderately acid discharge and the flow from the mine ranged from 7 to 150
gallons per minute. Two drifts were sealed by pneumatically placing lime-
stone aggregate in the openings and then grouting the aggregate with a cement
grout. A cross-section of the installation showing construction details is pre-
sented in Figure 11. Sealing reduced the flow by 85 percent, but leakage
occurred through and around the seal.
Remedial grouting was performed using other grout slurries in an
attempt to reduce the flow further. Essentially there was little reduction in
flow as a result of the remedial work. The grout slurries used in the remedial
grouting were:
1. A grout slurry consisting of preblended 50% Portland cement and 50% fly
ash by volume, with 18% salt and 0.4% Halad-9. Halad-9 is a Halliburton
additive to prevent water being lost into permeable formations due to ap-
plied pressure. This grout slurry was chosen because of low water loss
and good expansive characteristics. The grout slurry was mixed at a
weight of 14.5 pounds per gallon using impounded mine water.
2. Halliburton's DOC slurry which consists of cement particles surrounded
by a hydrocarbon base fluid incorporating a surface-active agent, or ker-
osene, cement and a dispersant type surfactant. These materials are
mixed to form a slurry that remains inactive unless contacted by water.
The slurry will absorb water like a sponge to cause a hard dense set.
3. The cement-fly ash mixture used in No. 1 with the addition of Flocele, a
shredded cellophane, as a plugging material.
The cost figures for construction of the two limestone aggregate seals
and later remedial grouting are presented in Table 7. The total cost was
estimated to be $17, 696. 00 for two seals or $8, 848. 00 per seal.
Reinforced Concrete Hydraulic Seal
Figures 12 and 13 show a proposed design for a reinforced concrete
hydraulic seal. The seal was designed by the Ebensburg Office of the Penn-
sylvania Department of Environmental Resources'*") and is to be constructed
at the Essen No. 2 Mine, Chartiers Creek Watershed, Allegheny County,
Pennsylvania, as part of Operation Scarlift Project SL 102-6. Construction
of this type of seal requires excavation of a hitch within the mine heading to
firmly anchor the seal. In addition to the hitch, mine timbering and the con-
struction of form walls are necessary. Pressure curtain grouting will be
extended a minimum of 50 feet on both sides of the mine entry. The grout
curtain holes drilled from the surface will be on ten (10) foot centers on
alignment with the seal.
-89-
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TABLE 7
COST.DATA
Grouted Limestone Aggregate Seals
Mine No. 40-016, Two Openings
Harrison County, West Virginia
Cleaning
Aggregate
Placement
Aggregate
Grouting
Additional
Remedial Grouting
Work
Equip. Rental
Labor @ $5.00/Hr. 24 Hours
Total
Equip. Rental
Material @ $3. 30/Ton 300 Tons
Labor @ $5.00/Hr. 128 Hours
Total
Equip. Rental
Material
Labor @ $5. 00/Hr. 144 Hours
Total
Equip. , Materials
and Labor
Site Preparation and
Restoration
Total
Total Cost for 2 Openings
Cost per Opening
$ 267.00
120.00
$ 387.00
$ 3, 060.00
990.00
640.00
$ 4,690. 00
$ 1,322.00
3,260. 00
720. 00
$ 5,302.00
*$ 6,007. 00
1,310.00
$ 7,317.00
$17,696.00
$ 8,848.00
*Drilling and preparation of grout holes accounted for $1, 468. 00 of this
cost.
Source: Halliburton Co.(7) and Wenzel(15)
-91-
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The project has not gone out for bids as yet and engineers estimates
were not available. However, the total cost, including construction of a
minimum of 100 feet of grout curtain, should be between $15, 000 to $20, 000.
Summary of Costs for Sealing Accessible Mine Openings
The following list summarizes available recent information on actual
and anticipated costs for sealing accessible mine openings including remedial
grouting costs.
Type of Hydraulic Seal Location Total Cost
Quick Setting Doable Harrison County, $ 9,449.00
Bulkhead Seal - Mine 62-008 West Virginia
Quick Setting Double Harrison County, $ 9,463.00
Bulkhead Seal - Mine RT5-2 West Virginia
Quick Setting Single Harrison County, $ 3,564.00
Bulkhead Seal - Mine 62-008 West Virginia
Expendible Grout Retainer Harrison County, $18, 000. 00
Seal - Mine 14-042A West Virginia (Estimated)
Grouted Aggregate Seals Harrison County, $ 8, 848. OO/
(Two Seals) Mine 40-016 West Virginia seal
Reinforced Concrete Seal Allegheny County, $15, 000. 00 to
Essen No. 2 Mine Pennsylvania $20,000.00
The cost of sealing accessible mine openings varies greatly and de-
pends on site conditions and type of seal proposed. The work performed by
Halliburton Company was experimental and in most cases was not effective
in completely sealing a mine. It appears successful mine sealing requires
curtain grouting because the rock above and to either side of the mine open-
ing is usually fractured allowing flow from the sealed mine.
Using one of the Halliburton methods of seal construction, drift mines
probably can be sealed at an average cost of $10,000 including remedial
grouting, if a small flow from the mine can be tolerated. How long these
seals will be effective is not known and it is possible substantial flows may
occur from openings in a few years.
A more permanent, water tight seal such as the one proposed by the
Pennsylvania Department of Environmental Resources for Essen Mine No. 2
could cost as much as the average grouted double bulkhead seal installed at
inaccessible mine entries in Moraine State Park and Slippery Rock Creek.
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Estimated Cost for Grouted Doable Bulkhead Seal
The following is a tabulation of average unit and quantity costs for con-
struction of grouted double bulkhead seals at abandoned mines based on costs
for the 93 seals installed at Moraine State Park and Slippery Rock Creek.
Unit
Item Unit Price Quantity Cost
1. Mine Sealing Seal $8,000.00 1 $ 8,000.00
2. Observation Drill Holes
a) Drilling 6" Holes L. F. 4.00 80 320.00
b) Casing Left in Place L. F. 3.20 40 128.00
3. Curtain Grouting
a) Drilling 3" Min. Holes L. F. 2.50 1,700 4,250.00
b) Cement for Grouting Sacks 5.70 900 5,130.00
c) Fly ash for Grouting Tons 15.00 75 1,500.00
d) Sand for Grouting Tons 20.00 1 20.00
e) Admixture for Grouting Sacks 4.00 3 12.00
f) Pressure Testing Hours 20.00 8 160.00
4. Mobilization & Demobilization L.S. 1,000.00 1 1, OOP. 00
Total Cost per Seal $20,520.00
Based on this tabulation, an estimated cost of $21, 000 per seal should
be used when applied to the Monongahela River Basin to allow for increased
construction costs.
Factors Affecting Cost of Hydraulic Mine Seals
Important factors that can affect the cost of hydraulic mine sealing
projects are:
1. Condition of portal
2. Degree of fracturing in rock adjacent to portal
3. Thickness of overburden above mine roof
4. Width of barrier between outcrop and mine workings
5. General character of rock along outcrop
6. The maximum hydraulic head that can develop after mine sealing
7. The availability of accurate mine maps
8. Accessibility of project area and haul distances
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9. Site preparation
10. Type of seal to be constructed
11. Availability and costs of materials, equipment and labor
LIMESTONE BARRIER MINE SEALING (PERMEABLE PLUG)
The principle involved in design of a permeable plug of graded lime-
stone aggregate is in-place treatment of acid mine drainage as it passes
through the plug. The aggregate must be so graded that acid mine water flow-
ing through the plug has sufficient retention time to be partially or completely
neutralized. As acid water reacts with the limestone, iron hydroxide and
possibly calcium sulfate are precipitated and eventually the aggregate void
spaces are filled. The final result is a solid plug which seals ths mine.
It is difficult to classify a permeable plug seal because of its assumed
changing characteristics. If the plug performs according to design assumptions,
there is an initial reduction in volume of discharge and an improvement in
quality of the mine water which is discharged. At this stage it cannot be com-
pared with an air seal because air can enter the mine through aggregate void
spaces, and in addition, mine water is being treated. As precipitates form,
there should be further reductions in mine water discharges. Theoretically,
the end result is a hydraulic seal.
Research and development for design of a permeable plug was performed
by the Halliburton Company^ ' under contract to the Environmental Protection
Agency. Extensive laboratory tests and research followed by field tests indi-
cated this type of seal showed promise. Two drift mines in Harrison County,
West Virginia were sealed with permeable plugs as part of this study.
Mine No. 62-008, Opening No. 3
This mine near Clarksburg, West Virginia had a flow of about 3 gallons
per minute, a pH of 3 and on acidity of 300 mg/1. Placement of AASHO No. 8
aggregate was performed pneumatically. The completed seal filled the mine
entry for a length of 36 feet at the base and 25 feet at roof contact. The drift
measured 52 inches by 1Z feet. A total of 67 tons of limestone aggregate was
emplaced. The construction cost was $3, 048.00 as follows:
Item Cost
Site Preparation $ 756.00
Materials 237.00
Equipment and Operators 2, 055. 00
Total $3,048.00
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Monitoring of the water flowing through the limestone plug showed a.
reduction in acidity to 112 mg/1 and an increase in pH (6.3 to 6.9), but there
was no reduction in flow from the mine.
Mine No. RT5-2, Opening No. 2
The second permeable plug was constructed at Opening No. 2 of Mine
RT5-2. This opening was discovered after Opening No. 1 had been success-
fully sealed with a quick setting double bulkhead seal. The opening was filled
with AASHO No. 8 crushed limestone blended with approximately 15% agricul-
tural lime. The aggregate was pneumatically placed against a roof fall and
165 tons of material was emplaced. The pneumatic placement was hampered
by the extreme amount of dust created when the limestone was blown into the
mine drift. In order to combat this problem, the ratio of lime dust was later
reduced to 10% and a pump was used to spray a jet of water. This helped to
some degree, but the dust problem was still bad.
The upper portion of the limestone plug was grouted using approximately
100 cubic feet of Halliburton LIGHT Cement slurry. This was done to insure
a seal along the roof section. Figure 14 presents a section view of the seal
and Figure 7 is a plan view showing the relationship of Openings No. 1 and No.
2. A retaining wall was built in front of the opening with a 90 degree weir to
measure flow rate. The graded aggregate seal was constructed at a cost of
$8,463.00.
Item Cost
Site Preparation $3,447.00
Materials 1,696.00
Equipment and Operators 3, 320. 00
Total $8,463.00
The cost was higher than the previous seal of this type because of ex-
cessive excavation required to prepare the opening, the extra materials re-
quired for grouting the upper section and a corresponding increase in the
necessary equipment.
Monitoring of the completed installation showed the initial flow of 25
gallons per minute with a head of 3. 3 feet of impounded water diminshed to
a flow of 3.6 gallons per minute with a head of 5.44 feet in about 24 days.
Analyses made of the mine water discharge before and after installation of
the seal indicate a. marked improvement in water quality.
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Before Sealing After Sealing
pH 2.9 to 3.2 5.6 to 6. 3
Acidity 512 to 765 mg/1 0 to 102 mg/1
Iron 104 to 282 mg/1 36 to 57 mg/1
Sulfate 868 to 1, 152 mg/1 780 to 940 mg/1
It is difficult to estimate an average unit cost for this type of seal be-
cause only two have been constructed as part of a demonstration project. A
unit cost per mine seal of $7, 500. 00 is recommended for estimating purposes
in the Monongahela River Basin.
DRY MINE SEALS
An effective mine sealing program requires the sealing of all openings
and surface areas which permit passage of air and water into the mine. If a
mine has an acid discharge at one or more openings, dry seals are used in
conjunction with air, hydraulic or permeable plug seals to seal the openings
which do not have a discharge. In the case of a hydraulic seal, the hydro-
static head that is developed should not cause significant hydrostatic pressure
in the area of a dry seal.
Dry sealing can be defined as the complete closure of mine drifts,
slopes, shafts, subsidence areas, fractures and other openings with imper-
meable material or structures at locations where there will be very little or
no hydrostatic pressure. Dry mine seals can be of concrete block or mas-
onry construction or openings can be filled with clay, concrete or other suit-
able materials. This type of sealing is generally confined to openings on the
"high" side of the mine where the body of the mine workings lie to the dip.
The cost of a dry seal can vary greatly and the cost will depend on the
opening to be sealed, its extent, condition and accessibility and the material
used in construction. Drifts, shafts, subsidence areas and surface areas with
fractures that allow passage of air and percolation of water into the mine may
only require a fill or a covering of impervious material. Although the cost of
this work could be measured on a cubic yard basis, the work is usually per-
formed for a lump sum fee for the job, i.e. , so many areas to be sealed. An
example would be the dry mine sealing performed at Moraine State Park in
conjunction with the hydraulic sealing program. This work involved the seal-
ing of a total of 23 air shafts, drifts and other openings scattered throughout
the area using available clay and other suitable materials. The lump sum fee
was $28, 000 or an average cost per seal of $1, 217. This cost also included
soil treatment and seeding of sealed areas.
reports that 450 subsidence holes were filled and 101 seals con-
structed as part of the Elkins Demonstration Project in West Virginia. A
total of 41 openings were sealed with clay, but cost data was recorded for only
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two areas containing a total of 16 openings. The costs are based on the rental
of equipment. The cost data for the 16 compacted clay seals as presented in
Scott, et al.(17) is:
Cu. Yds. Average
Work No. of Compacted Total Cost per Cu. Yd./ Cost/
Area Seals Backfill Cost Seal Seal Cu. Yd.
1-9 10 10,490 $ 9,500 $ 950 1,049 $0.91
10 _6_ 11,670 $14, 160 $2,360 1,945 $1.21
16 22,160 $23,660 $1,479 1,381 $1.07
The cost per cubic yard of material for Work Area 10 was higher be-
cause the haulage distance from the borrow area was greater.
The cost of a masonry dry mine seal will depend on several factors,
such as: 1) accessibility of the mine, 2) condition of the mine opening, 3)
method of construction, 4) the volume of materials required including nec-
essary timber, and 5) other items pertinent to seal construction. Recent costs
are available for two projects where masonry dry seals were installed.
As part of the Elkins Demonstration Project' ', a total of 43 masonry
dry seals were constructed. Seal construction consisted of a single solid wall
of two courses of fly ash blocks and the seals were coated on both sides with
urethane foam. Mine openings were timbered to keep the weight of the roof
off the seals. The average cost per seal was $2,210 and costs per individual
seal ranged from $1, 358 to $6, 376.
Seven masonry dry seals were installed at a mine site northeast of Pitts-
burgh in 1966 under the direction of the U.S. Bureau of Mines(°). The seals
were erected on concrete footers and hitched 12" into ribs and roof. The seals
were of double-wall, cored concrete block construction with 25 percent of the
cement replaced by fly ash. A 2" space between the courses was filled with
urethane foam. Urethane foam was also used to coat the inby and outby faces
of the seals and to fill the hitch spaces. The average cost per seal was $5, 089.
AIR MINE SEALS
Air mine sealing remains a controversial water pollution abatement
measure. At some abandoned mine sites, air sealing has resulted in a signifi-
cant reduction in acidity of the discharge, but at other mine sites there has been
very little or no reduction in acidity in spite of an extensive air sealing program.
It appears that the thickness and competence of the overburden above the mine
are important factors in the success or failure of an air sealing project. As
pointed out by Hill(^), air sealing was not successful at Elkins because a reduc-
tion in acidity cannot be expected in sealing a large complex mine with a ten-
dency for subsidence. Moebs and Krickovic^ ', on the other hand, were
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successful in reducing the acidity of a discharge from a mine that had a com-
petent rock overburden and only one subsidence depression, whereas at Elkins,
450 subsidence holes had to be filled.
Conventional air sealing entails the closing of all openings to the mine
with impermeable material or structures, except that an air trap is placed in
one or more of the lower seals. Air sealing requires a comprehensive pro-
gram of engineering which may be difficult and expensive under adverse con-
ditions, with no guarantee of total success^°). It is the opinion of Moebs and
Krickovio") that abandoned mines above drainage which are discharging acid
water should be evaluated as individual projects and if the geological conditions
are favorable, they should be air sealed and have water diverted from them to
the fullest extent practicable.
The method of construction of air seals at Elkins, West Virginia was
essentially the same as for masonry dry seals, except that air seals had two
or three walls. One of the walls was solid, except for two blocks being re-
moved from the base. The outer wall was constructed to a higher elevation
than the opening in the inner wall in order to form a water trap that would pre-
vent air from entering the mine. A total of 1Z air seals were installed and the
average cost was $4,076 per seal. Costs per individual seal ranged from
$3,128 to $5,032.
The U.S. Bureau of Mines project' ' sealed a small, abandoned, highly
acid drainage drift about 40 miles northeast of Pittsburgh. The mine is repre-
sentative of those which are responsible for about 35 percent of the stream
pollution in the coal regions of Appalachia. The following topographic and
geologic conditions made the mine favorable for air sealing:
1. The mine was overlain by competent siltstone and sandstone.
2. The overburden was 100 to 200 feet thick over more than 50 percent of the
area above the mine.
3. Mine roof conditions were very good.
4. Most of the pyritic sulfur from which acid is formed occurs in the bottom
portion of the coal bed and in the top layer of the underclay.
In addition to the installation of the seven masonry dry seals at this mine,
one masonry air seal of similar construction was installed along with the two
barriers to form the air traps. The entry width was 22 feet and the height was
5 feet. Figure 15 shows the general arrangement of an air seal. The cost of
the air seal was $14, 800.
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The total cost for sealing and related work and reclamation was $57,420
on this project and is itemized as follows:
Seals and related work:
Timber, treated (24, 390 bd ft) $ 5, 146
Urethane foam, 2, 000-lb (755 sq ft) 3,510
Masonry blocks (2, 002) 524
Pipe (167 ft) 528
Concrete (28 cu yd) 504
Miscellaneous 288
Total material $10,500
Equipment, including operator 8, 960
Labor (5,000 man-hours) 30,OOP
Total $49,460
Sealing 2 strip pits (3 acres), 1 surface subsidence
depression, and 1 caved entry $ 7, 000
Grading access roads and portal areas 960
Total $57,420
Of the $49,460 for seals, 61 percent was spent for labor, 21 percent
for materials, and 18 percent for equipment. Equipment costs were chiefly
related to excavation and cleanup of the entries in which seals were constructed
and to grading for drainage and stability around the portals. The significant
quantities and costs of materials used were as follows:
Material Unit Quantity Cost
Urethane foam per seal Ib. 222 $390
Timbering per sealed entry bd. ft. 3, 060 340
Masonry blocks per seal each 222 58
Concrete footers per seal cu. yd. 2.8 54
As a result of the mine sealing the acid load was reduced an average of
12 tons per year. The mean total acidity for a 2 year, 7 month period before
sealing was 514 rag/1 and for a 2 year, 8 month period after sealing it was 211
mg/1, an improvement in quality of 303 mg/1. The average monthly maximum
total acidity after-sealing was 247 mg/1, which is well below the minimum of
331 mg/1 before sealing. Figure 16 shows the average monthly total acidity
and flow rate of the mine effluent before and after sealing.
A somewhat lower volume of effluent after mine sealing indicates the
quantity of water directly entering the mine from the surface through entries
was less.
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-104-
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There is no doubt air sealing was effective in reducing acidity and
effluent volume, but it is interesting to conjecture what degree of abatement
would have occurred, if after dry sealing the mine, a permeable plug of
limestone aggregate was installed instead of an air seal. A demonstration
project utilizing the permeable plug principle at a small abandoned mine with
similar topography and geology may be rewarding.
SUMMARY OF COSTS FOR DRY AND AIR SEALS
The following tabulation summarizes available recent cost data for
dry and air mine sealing:
No. of Aver. Cost Range
Type of Seal Project Seals per Seal in Cost
Dry Seal (Clay) Moraine S. P. 23 $ 1,217
Elkins 16 1,479
Dry Seal (Masonry) Elkins 43 $ 2,210 $1, 358-$6, 376
Bur. Mines 17 5, 089
Air Seal (Masonry) Elkins 12 $4,076 $3, 128-$5, 032
Bur. Mines 1 * 14, 800
*The entry was 22 feet wide.
For general estimating purposes in the Monongahela River Basin it is
suggested that the following average costs per seal be used:
Dry Seal (Clay) $1,500
Dry Seal (Masonry) $3,500
Air Seal (Masonry) $5,000
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REFERENCES
1. Foreman, John W., 1971, Deep Mine Sealing: Acid Mine Drainage Work-
shop, Athens, Ohio by Ohio Univ., 27 p. (BCR 71-47)
2. Maize, Richard, 1952, History and Progress Made in Mine Sealing to
Reduce the Flow of Acid Mine Water into the Streams of this Common-
wealth: Presented at Coal Mining Institute, Pittsburgh, December, 1952,
11 p. 12 figs. (BCR 52-31)
3. U.S. Public Health Service, 1942, Ohio River Pollution Survey, Final
Report to the Ohio River Committee, Supplement "C", Acid Mine Drainage
Studies: Office of Stream Sanitation, 68 p. (BCR 40-11)
4. Hill, Ronald D. , 1970, Elkins Mine Drainage Pollution Control Demon-
stration Project: Third Symp. Coal Mine Drainage Res. Preprints,
Pittsburgh, p. 284-303 (BCR 70-24)
5. Braley, S. A., 1962, Special Report on an Evaluation of Mj.ne Sealing:
Coal Industry Advisory Committee to the Ohio River Valley Sanitation
Commission, Mellon Institute, Res. Proj. No. 370-8, 33 p., 32 tables
and figs. (BCR 62-10)
6. Ohio River Valley Water Sanitation Commission, 1964, Principles and
Guide to Practices in the Control of Acid Mine-Drainage: Coal Industry
Advisory Committee, 30 p. (BCR 64-28)
7. Halliburton Company, 1970, New Mine Sealing Techniques for Water
Pollution Abatement: Federal Water Quality Adm. , Res. Ser. 14010
DMO 03/70, 163 p. (BCR 70-82)
8. Moebs, N. N. and Krickovic, S. , 1970, Air-Sealing Coal Mines to Reduce
Water Pollution: U.S. Bur. Mines Rept. Inv. 7354, 33 p. (BCR 70-1)
9. Gwin Engineers, Inc., 1968, Moraine State Park Watershed Area, Butler
County: Rept. to Pa. Dept. Mines Mineral Ind. , Mine Drainage Project
MD-8A, 109 p. (BCR 68-92)
10. Foreman, John W. , 1970, Evaluation of Pollution Abatement Procedures
in Moraine State Park: Third Symp. Coal Mine Drainage Res. Preprints,
Pittsburgh, p. 304-33 (BCR 70-25)
11. Foreman, John W. , 1972, Evaluation of Mine Sealing in Butler County,
Pennsylvania: Fourth Symp. Coal Mine Drainage Res. Preprints, Pitts-
burgh, p. 83-95 (BCR 72- )
12. Reinhold, R. H. , 1969, Mine Water Barrier: U.S. Pat. 3,469,405
(Sept. 30, 1969) to Layne-New York Co., Inc. 4 p. (BCR 69-58)
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13. Pennsylvania Department of Environmental Resources, 1972, Bid Form
and Special Requirements, Pressure Curtain Grouting and Reclamation,
Thomas Mills, Conemaugh Township, Somerset County, Pennsylvania:
Issued July 11, 1972, Contract No. SL 151-1A
14. Baker, A. A., 1967, Feasibility Study on the Application of Various
Grouting Agents, Techniques and Methods to the Abatement of Mine
Drainage Pollution, Part II - Selection and Recommendation of Twenty
Mine Sites: Halliburton Co., Rept. to Federal Water Quality Adm. ,
Monongahela River Mine Drainage Remedial Project, 286 p. (BCR 67-193)
15. Wenzel, R. W. , 1968, Feasibility Study on the Application of Various
Grouting Agents, Techniques and Methods to the Abatement of Mine
Drainage Pollution, Part IV - Additional Laboratory and Field Tests for
Evaluating and Improving Methods for Abating Mine Drainage Pollution:
Halliburton Co. , Rept. to Federal Water Pollution Control Adm. , Monon-
gahela River Mine Drainage Remedial Project, 236 p. (BCR 68-156)
16. Molinski, A. E. , 1972, Personal Communication: Source - Drawing No.
102, approved April 21, 1971 by Mr. Molinski, Chief Engineer, Ebensburg
Office, Pennsylvania Department of Environmental Resources
17. Scott, R. B., Hill, R. D. and Wilmoth, R. C., 1970, Cost of Reclamation
and Mine Drainage Abatement - Elkins Demonstration Project: U. S.
Environmental Protection Agency, Water Quality Office, Res. Ser.
14010 --- 10/70, 27 p. , revision of Paper 70-AG-349, Soc. Mining Eng.
Meeting, St. Louis, October 21-23, 1970. (BCR 70-70)
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STREAM DIVERSION
TABLE OF CONTENTS
Page No.
Introduction HI
Cost of Stream Diversion HI
References 113
LIST OF TABLES
1. Stream Diversion Costs for Operation Scarlift Projects H2
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STREAM DIVERSION
Introduction
Water diversion is frequently utilized in active surface and deep mine
operations to ease the physical and financial burden of pumping large quantities
of water. In surface mining operations the most commonly used method is to
construct a ditch on the uphill (highwall) side of the open cut. Other methods
used in surface mining are 1) diversion of streams into new channels to pre-
vent seepage into or flooding of the work area, and 2) construction of trenches
or installation of pipes at the downhill side of the open cut to remove water as
quickly as possible. Preventing the infiltration of surface waters into deep
mine workings is much more complicated, but can be accomplished to a cer-
tain extent by diversion of stream channels or the lining of stream channels
with impervious materials where they cross over deep mine workings.
When water comes in contact with oxidized sulfuritic materials, acid
mine waters are produced. A considerable quantity of acid mine drainage can
be prevented by diverting stream waters from sources of acid pollution. This
is particularly true when the water course upstream of the pollution source is
relatively unpolluted.
If the stream flow cannot be diverted into a new channel because of
topographic limitations, it is usually feasible to reconstruct the channel so
that the flow will be more efficient, thereby reducing contact time with the
acid material. The channel can be lined with impervious material and in
cases where there is seepage or flow into a deep mine it can be prevented by
sealing the mine opening with clay or other suitable materials.
Cost of Stream Diversion
This section of the report is concerned with the cost of preventing acid
mine drainage pollution by diverting stream flow away from surface and deep
mines which are pollution sources. Only three stream diversion projects were
found among the many projects performed by the Commonwealth of Pennsylvania
under the Operation Scarlift Project program. The projects were in different
areas of Pennsylvania, have significant lengths of channel construction and the
volumes of excavation appear to be representative of what can be expected in
this type of project. The cost per lineal foot of channel ranged from $12.00 to
a high of $27.00 including all supplemental costs. Table 1 presents the per-
tinent data on these projects.
The cost experience in mine related stream diversion projects is limited,
but there is, however, a large amount of applicable experience available in con-
struction of channel changes for streams in connection with highway projects.
This cost information is difficult to isolate because equipment needs are not
separated in the mass contracts. It is estimated, however, that the costs
should approximate the following:
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Soil and shale excavation - $0.80/C.Y.
Premium for rock excavation - $0. 50/C. Y.
Equipment costs -$0. 35/C.Y.
In addition to these costs, the channel slopes whould be seeded with a
grass-legume mixture at an estimated cost of $450 per acre of slope area.
For the Monongahela River Basin a cost estimate of $20.00/L.F. will
allow for increased construction costs, channel slope grading, soil treatment
and seeding.
TABLE 1
STREAM DIVERSION COSTS FOR OPERATION SCARLIFT PROJECTS
Project No. SL 102-1-1 SL 135-1 SL 143-1
Location Chartiers Creek Catawissa Creek Alder Run
Allegheny County Luzerne County Clearfield County
Length (L.F. ) 4,200 1,720 4,000
Avg. Depth (Ft.) 5 10 5
Excavation
Quantity (C.Y.) 11,000 17,300 107,000
Unit Price (C.Y.) $1.50 $2.60 $0.61
Total Cost $65,100 $30,500 $108,000
Cost per L.F. $15.50 $12.00 $27.00
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REFERENCES
1. Pennsylvania Department of Environmental Resources, 1972, Infor-
mation in Files of Office of Engineering and Construction: Harrisburg.
2. Michael Baker, Jr., Inc., 1972, Recent Cost Estimates for Highway
Channel Changes: Highway Division, Beaver, Pennsylvania.
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TREATMENT OF MINE DRAINAGE
TABLE OF CONTENTS
Page No.
Chemistry and Classification of Mine Drainage 125
Neutralization .
Principle of Neutralization 128
Neutralizing Agents 128
Chemistry of Lime Neutralization 131
Chemistry of Limestone Neutralization 131
Neutralization of Mine Drainage with
High Ferrous Iron Content 136
BCR Limestone Treatment Process 137
U.S. Bureau of Mines Limestone Treatment Process 157
Combination Lime stone -Lime Treatment Process 177
Combination Lime -Limestone Neutralization with
Rotary Precoat Filtration for Sludge Dewatering 181
Electrochemical Oxidation Followed by Limestone
Neutralization 189
Biochemical Oxidation Followed by Limestone
Neutralization 198
Ozone Oxidation Followed by Limestone Neutralization 206
Neutralization of Mine Drainage with High Ferric
Iron Content 222
Mine Drainage Treatment Using Hydrated Lime 224
Flash Distillation Process 256
Ion Exchange Processes 261
Reverse Osmosis Process 269
Submerged Coal Refuse Combustion Process 295
Freezing (Crystallization) Process 303
Electrodialysis Process 307
Foam Separation (Fractionation) Process 309
Neutradesulfating Process 310
References 312
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LIST OF TABLES
Page No.
1. Classification of Mine Drainage 127
2. List of Neutralizing Agents Suggested for Acid Mine
Drainage Treatment 129
3. Basis of Estimated Costs of Limestone Treatment, Various
Size Treatment Plants - BCR Process 144
4. Estimate of Capital Cost for Limestone Treatment Plant,
South Greensburg Coal Mine Drainage - BCR Process 145
5. Auxiliary Equipment Costs - U.S. Bureau of Mine Lime-
stone Treatment Process 162
Limestone Treatment Cost Estimates - U.S. Bureau of
Mines Process
6. 100, 000 GPD Plant Capacity 163
7. 300,000 GPD Plant Capacity 164
8. 500, 000 GPD Plant Capacity 165
9. 1, 500, 000 GPD Plant Capacity 166
10. 2 Million GPD Plant Capacity 167
11. 6 Million GPD Plant Capacity 168
12. Lime stone-Lime vs. Lime at 5 GPM
EPA - Norton, West Virginia 179
13. Estimated Capital Costs for Various Size Plants Using
Increased Efficiency Limes tone-Lime Process
Johns-Manville Products Corporation 184
14. Estimated Operating Costs for Various Size Plants Using
Increased Efficiency Lime stone-Lime Process
Johns-Manville Products Corporation. 185
15. Plant Investments, Electrochemical Oxidation Method
Tyco Laboratories, Inc. 194
-116-
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Page No,
16. Estimated Operating Expenses for Direct Electrochemical
Oxidation Treatment Plants - Tyco Laboratories, Inc. 195
17. Typical Operating Characteristics of Pilot Scale Biochemical
Oxidation and Limestone Neutralization Process 201
Ozone Oxidation Followed by Limestone Neutralization -
Brookhaven National Laboratory
18. AMD Plant Cost 210
19. AMD Treatment Plant Operating Costs 211
20. AMD Treatment Total Operating Costs 212
21. Ozone Generated in 40 Ton/Day Plant,
Shipped to AMD Site 213
22. Ozone Generated in 200 Ton/Day Plant,
Shipped to AMD Site 214
23. Total Investment Costs for AMD Treatment Using
On-Site Ozone with Recycled Oxygen Feed 215
24, Comparison of AMD Total Treatment Costs 216
25, Cost Breakdown for Total AMD Treatment of
Pennsylvania AMD Streams 221
26. Cost of Brine Disposal in Evaporation Ponds 228
27. Estimated Costs of Deep Well Disposal 228
28. Acid Mine Drainage Treatment Plant Capital Expenditures -
Operation Yellowboy Projects 230
29. Annual Operating Costs - Operation Yellowboy Projects 231
30. Total Annual Unit Costs - Operation Yellowboy Projects 232
31. Estimated Costs of Neutralizing Highly Acid Mine Water
Using Hydrated Lime 233
32. Estimated Costs of Neutralizing Moderately Acid Mine
Water Using Hydrated Lime 233
-117-
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Page No.
33. Estimated Costs of Neutralizing Weak Acid Mine
Water Using Hydrated Lime 235
34. Treatment Plant Operating Data, Slippery Rock Creek
North Branch - 1971 242
35. Little Scrubgrass Creek Lime Treatment Plant
Monthly Operating Expenses 250
Multiple Stage Flash Distillation Acid Mine Drainage
Treatment Plant - Westinghouse Electric Corporation
36. Cost Estimate 258
37. Summary of Operating Costs 259
38. Interim Operating Costs 260
39. Summary of Operating Data and Design Water Quality -
Ion Exchange Treatment Plant, Philipsburg, Pa. 266
40. Reverse Osmosis Capital Costs - Summary of Reference
Conditions Used as a Basis for Tables 41, 42, 43, 45, 46,
47, 48, 49, 50, 51 274
Estimated Capital Costs for Reverse Osmosis Process
41. for Cases Cited in Table 40 275
42. with Lime Neutralization for Brine Disposal 276
43. with Deep Well Brine Disposal 277
44. Estimated Capital Costs vs. Capacity for Reverse
Osmosis Process with Deep Well Brine Disposal 278
45. Estimated Operating Costs for Reverse Osmosis Process
for Cases Cited in Tables 40 and 41 279
Estimated Operating Costs for Reverse Osmosis Process
with Lime Neutralization for Brine Disposal
46. in Dollars Per Thousand Gallons of AMD Treated
Using Hydrated Lime 280
-118-
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Page No.
47. in Dollars Per Thousand Gallons of Product Water
Using Hydrated Lime 280
48. in Dollars Per Thousand Gallons of AMD Treated
Using Limestone 281
49. in Dollars Per Thousand Gallons of Product Water
Using Limestone 281
Estimated Operating Costs for Reverse Osmosis Process
with Deep Well Brine Disposal
50. in Dollars Per Thousand Gallons of AMD Treated 282
51. in Dollars Per Thousand Gallons of Product Water 282
52. Estimated Operating Costs vs. Capacity for Reverse
Osmosis Process with Deep Well Brine Disposal 283
53. Typical Raw Water Quality Characteristics of
Mocanaqua Discharge, Pennsylvania 289
54. Comparison of Water Production Capabilities -
Reverse Osmosis Treatment, Mocanaqua, Pa. 290
55. Relative Cost - Reverse Osmosis Treatment,
Mocanaqua, Pa. 290
56. Major Cost Items for 0.75 MGD Reverse Osmosis
Treatment Plant - Rex Chainbelt, Inc. 293
Two-Stage Coal Refuse Combustion Process
57. Acid Mine Drainage Compositions Used in Study 299
58. Ultimate Analysis of Coal Refuse 299
59. Capital Investment for Various Size Acid Mine
Drainage Treatment Plants 300
60. Determination of Break-Even Price of Water -
5 MGD Acid Mine Drainage Treatment Plant 301
61. Summary of Crystallization Costs Using Kittanning Run,
Pennsylvania, Water as Feed 306
62. Electrodialysis Treatment Plant Costs Using Kittanning
Run, Pennsylvania, Water as Feed 308
-119-
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LIST OF FIGURES
Page No.
1. Solubility of Aluminum, Iron and Manganese in Acid
Mine Drainage at Various pH's 132
2. Solubility of Iron 133
3. Iron (II) Oxidation Rate at pH 2-1 134
4. Flow Diagram of Conceptual Limestone Treatment Process 138
Estimate of Capital Costs vs. Plant Capacity - BCR
Limestone Treatment with Sludge Dewatering
5. Total Capital Costs 146
6. Aeration Tank and Aerators, Reactor Tank and Mixers,
and Holding Lagoon 147
7. Sludge Dewatering Basin, Settling Basin Sludge Pumps,
Sludge Recirculating Pumps and Waste Sludge Pumps 148
8. Settling Basin, Control Building, Sludge Pump Well,
Chemical Feed Equipment and Control Equipment 149
9. Mechanical Piping and Electrical 150
10. Estimate of Operating vs. Plant Capacity - BCR
Limestone Treatment with Sludge Dewatering 151
11. Estimated Chemical Costs - BCR Limestone Treatment
Process 152
Estimated Costs (Cents/Thousand Gallons) - BCR Limestone
Treatment with Sludge Dewatering
12. Total Costs 153
13. Labor, Power and Maintenance and Repairs 154
14. Sludge Disposal and Capital Costs 155
15. Estimated Sludge Accumulation in One Year from BCR
Limestone Treatment Process 156
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Page No.
16. Flowsheet of Mine Water Treatment Process -
U.S. Bureau of Mines 157
Estimated Capital Costs vs. Plant Capacity for Limestone
Treatment Plant - U.S. Bureau of Mines
17. Iron as Fe++ = 50 PPM 169
18. Iron as Fe++ = 100 PPM 170
19. Iron as Fe++ = 500 PPM 171
20. Iron as Fe++ = 1000 PPM 172
Annual Operating Costs vs. Plant Capacity for
Limestone Treatment - U.S. Bureau of Mines
21. Iron as Fe++ = 50 PPM 173
22. Iron as Fe++ = 100 PPM 174
23. Iron as Fe++ = 500 PPM 175
24. Iron as Fe++ = 1000 PPM 176
25. Lime/Limestone Cost Ratio and Process Cost Reduction
Norton Mine Drainage Field Site, West Virginia 180
26. Flowsheet - Lime stone-Lime Neutralization with Rotary
Precoat Filtration of Sludge, Johns-Manville Products
Corporation 182
Estimated Capital Costs for Various Size Plants Using
Increased Efficiency Lime stone-Lime Process, Rotary
Precoat Filtration for Sludge Dewatering - Johns -
Manville Products Corporation
27. Total Capital Costs 186
28. Individual Capital Components 187
29. Estimated Operating Costs for Various Size Plants Using
Increased Efficiency Limes tone-Lime Process, Rotary
Precoat Filtration for Sludge Dewatering - Johns-Manville
Products Corporation 188
-121-
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Page No.
30. Oxidation Unit for Treating 6, 000 gal. /hr. ,
Electrochemical Oxidation Followed by Limestone
Neutralization - Tyco Laboratories, Inc. 190
31. Estimated Capital Costs vs. Plant Capacity for
Electrochemical Oxidation and Limestone Neutra-
lization Treatment - Tyco Laboratories, Inc. 196
32. Estimated Annual Operating Costs vs. Plant Capacity
for Electrochemical Oxidation and Limestone Neutra-
lization Treatment - Tyco Laboratories, Inc. 197
33. Flow Diagram of Complete Biochemical Oxidation
and Limestone Neutralization Process 199
34. Dimensioned Sketch of Experimental Pilot Scale
Biochemical Oxidation and Limestone Neutralization
Plant for Acid Mine Drainage Treatment 200
35. Flowsheet - Biochemical Iron Oxidation Limestone
Treatment Process, Hollywood, Pennsylvania 205
36. AMD Oxidation and Neutralization Process System,
Ozone Oxidation Followed by Limestone Neutralization
- Brookhaven National Laboratory 207
37. Total AMD Treatment Costs Using Ozone Electric
Discharge Ozonizers - Brookhaven National Laboratory 217
38. Total AMD Treatment Cost Using Electric-Discharge
Ozone - Brookhaven National Laboratory 218
39. Total AMD Treatment Cost Using Chemonuclear Ozone -
Brookhaven National Laboratory 219
40. Total Plant Investment Cost for AMD Treatment Using
On-Site Electric Discharge Ozone - Brookhaven National
Laboratory 220
41. Flow Diagram, HDS Demonstration Plant at Mine 32 -
Bethlehem Steel Corporation 227
42. Capital Cost vs. Plant Capacity - Hydrated Lime
Treatment Plant with Sludge Disposal 234
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Page No.
43. Total Capital Cost Vs. Plant Capacity - Hydrated
Lime Treatment Plant without Sludge Disposal 235
44. Total Operating Cost (Including Capital Costs ) -
Hydrated Lime Treatment 236
45. Duquesne Light Company Warwick Mine Portal No. 2
Mine Water Treatment Plant Flow Sheet 238
46. Effect of the Closing of the Michigan Limestone Co.
Plant at Boyers in December 1957 on Water Quality
in Slippery Rock Creek 241
47. Flow Diagram - Slippery Rock Creek Mine Drainage
Treatment Plant 244
48. Mountaineer Coal Co. , Williams Mine, Levi Moore
Discharge - Flow Diagram 246
49. Schematic Diagram - Little Scrubgrass Treatment Plant 249
50. Flow Diagram of Rausch Creek Treatment Plant 252
51. Flow Schematic - Altoona Mine Drainage Treatment Plant 254
52. Mixmeter Model 65AE - Typical Installation Arrangement 255
53. Low Temperature MSF Evaporator Process for Treat-
ment of AMD (Selective Recovery of Dissolved Minerals) 257
54. Schematic of Proposed Treatment Plant,
Philipsburg, Pennsylvania 265
55. Flow Diagram - Flow Type Ion Exchange Units,
Smith Township, Pennsylvania 268
56. Operating Cost vs. Plant Capacity - Reverse Osmosis
+ Brine Disposal (Product Water) 284
57. Operating Cost vs. Plant Capacity - Reverse Osmosis
with and without Brine Disposal (AMD Treated) 285
58. Capital Cost of Reverse Osmosis Plant with Brine
Disposal vs. Plant Capacity (Product Water) 286
-123-
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Page No.
59, Capital Cost of Reverse Osmosis Plant with Brine
Disposal vs. Plant Capacity (AMD Treated) 287
60. Flow Sheet Used for Cost Estimated, 0.75 MGD
Reverse Osmosis Acid Mine Drainage Treatment
Plant - Rex Chainbelt, Inc. 292
61. Flow Chart-Acid Mine Water Treatment Process
Using Two-Stage Coal Refuse Combustion Process
- Black, Sivalls & Bryson, Inc. 296
62. Effect of Plant Capacity on Capital Investment -
Two-Stage Coal Refuse Combustion Process 302
63. Flow Diagram for Partial Freezing of Acid Mine
Water - Applied Science Laboratories 304
64. Schematic for AMD Neutradesulfating -
Catlytic, Inc. 311
-124-
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TREATMENT OF MINE DRAINAGE
In the last few years, the technology of mine drainage treatment has
been reviewed in a number of publications. An excellent review is "Mine
Drainage Treatment, State of the Art and Research Needs" by Ronald D.
Hill.' ' Most of the discussion in the first part of this section, particularly
on mine drainage chemistry and the classification of mine drainage, was
taken verbatim from Hill's publication.
CHEMISTRY AND CLASSIFICATION OF MINE DRAINAGE
The type of drainage produced by a particular mine is dependent upon
the product mined and the nature of the surrounding geologic formation. In
the case of coal mining, it is dependent upon the amount of sulfides present;
the spatial distribution of these sulfides; the crystallinity of the pyrite; the
size of the individual sulfide particles; the presence of bacteria associated
with acid mine drainage; and the magnitude of the fluctuation of the water
level within the mine, if the workings are below drainage. In addition, the
presence or absence of calcium in the sulfide aggregates seems to have some
effect upon the rate of sulfide oxidation and decomposition.
Wide variations exist in the chemical characteristics of mine drain-
age and some mine waters are decidedly acid whereas others are fairly alk-
aline. Generally, acid mine drainage can be said to have a low pH, net
acidity (acidity greater than alkalinity), high iron (iron II and/or iron III),
high sulfates and significant amounts of aluminum, manganese, calcium and
magnesium. Alkaline mine drainage generally can be said to have a pH near
or greater than neutrality, net alkalinity, high sulfate, significant calcium,
magnesium and manganese, and low aluminum. Corbett and Growitz^ ' re-
ported that the zinc, cadmium, beryllium, copper, silver, nickel, cobalt,
lead, chromium, vanadium, barium and strontium concentrations of coal
mine drainage were less than 1 mg/1. Analyses of mine drainage samples
collected in West Virginia and Pennsylvania by personnel from the Environ-
mental Protection Agency revealed concentration of similar magnitude.
Although the exact mechanism is not fully understood, acid mine
drainage results from the oxidation of pyrite (FeS?) as illustrated in Equa-
tion (1):
2 FeS2 + 2 H2O + 7 02 — 2 FeSO4 + 2 H2SC>4 (1)
Subsequent oxidation of ferrous sulfate produces a ferric sulfate:
4 FeSO4 + 2 H2SO4 + C>2 --2 Fe2(SO4)3 + 2 H2O (2)
The reaction may then proceed to form a ferric hydroxide or basic
ferric sulfate:
-125-
-------
Fe2(S04)3 + 6 H2O — — 2 Fe(OH)3 J + 3 H2SO4 (3)
) + 2 H20 -- -2 Fe(OH)(SO4) + H2SO4 (4)
Pyrite oxidation also occurs due to ferric iron as illustrated in equa-
tion (5):
14 Fe+++ + FeS2 + 8 H2O — — 15 Fe + f f 2 SO4= + 16 H+ (5)
By either mechanism, an acid water is produced and the pH is lower-
ed. At low pH's many metallic ions in the mine, for example aluminum and
manganese, become more soluble and enter into the mine discharge.
Mine drainage is a complex solution varying in quality from seam to
seam, mine to mine, and even within the same mine. The water quality
from mines low in pyrite may be alkaline and closely resemble ground water.
Often mines produce water high in ferrous iron and acidity, indicating that
reactions (1) and/or (5) are occurring. The discharge may have high ferric
iron and acidity concentration, indicating that reactions (2) and (3) are occur-
ring. The discharge may also have been partially neutralized within the
mines thus reducing the acidity level.
Although there is no "typical" mine drainage, waters discharging
from mines can be divided into four general classes as shown in Table 1.
The wide variations in mine drainage characteristics indicate that a
number of treatment methods may be applicable. The best method for any one
site will depend on the quality of the mine discharge and the ultimate use of the
water. Treatment to meet stream water standards will be different from that
needed to meet domestic and industrial water use standards.
The following mine drainage treatment methods are discussed:
1. Neutralization
a) Acid mine water with high ferric iron content
b) Acid mine water with high ferrous iron content
Methods of oxidizing ferrous ion to ferric ion will also be discussed.
2. Flash Distillation
3. Ion Exchange
4. Reverse Osmosis
5. Submerged Coal Refuse Combustion Process
-126-
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6. Freezing
7. Electrodialysis
8. Foam Separation
9. Neutradesulfating Process
NEUTRALIZATION
Principle of Neutralization - In ;he neutralization process an alkali is mixed
with acid mine waters to neutralize the acid and to precipitate the contamin-
ating metal salts, which can then be separated by sedimentation and/or fil-
tration. The metal salts commonly found in acid mine drainage are separated
because they are less soluble at neutral or higher pH's than at lower pH's.
Neutralizing Agents - The list of neutralizing agents suggested for acid mine
drainage is presented in Table 2. While most neutralization work to date has
utilized lime and limestone, other agents may be used successfully in some
situations.
The choice of an alkaline agent should be based on the following con-
siderations:
a) Cost of Agent - The cheapest agent capable of fulfilling the require-
ments should be used.
b) Availability of Agent - Availability is partially reflected in cost.
The availability of certain alkaline materials, such as a by-product
of another industry, may not be available over a long term.
c) Basicity Factor - The amoant of alkali per unit weight of material
varies among different alkaline agents. Basicity factor is defined
as the grams of calcium carbonate equivalent per gram of alkaline
agent. The basicity factor is a useful tool in comparing the cost
of alkaline agents. The basicity factors for some commonly used
alkaline agents are given in Table 2.
d) Reaction Time - The reaction rates of alkaline agents vary over a
considerable range and are important factors in the size of mixing
tanks, etc.
e) Sludge Characteristic - The settling rate and properties of the sludge
are important factors in the design of settling tanks and lagoons, and
in the disposal of the sludge.
-128-
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TABLE 2
LIST OF NEUTRALIZING AGENTS
SUGGESTED FOR ACID MINE DRAINAGE TREATMENT
Neutralizing Agents
Calcium Oxide (Quick Lime)
Calcium Hydroxide (Hydrated Lime)
Calcium Carbonate (Limestone)
Calcium Magnesium Carbonate (Dolomite)
Magnesium Oxide
Magnesium Hydroxide
Sodium Hydroxide (Caustic Soda)
Sodium Carbonate (Soda Ash)
Sodium Sulfide
Potassium Hydroxide
Potassium Permanganate
Ammonia
Ammonium Hydroxide
Trisodium Phosphate
CaO
Ca(OH)2
CaCO,
(Ca-Mg)CO3
MgO
Mg(OH)2
NaOH
Na2CO3
Na2S
KOH
KMnO4
NH3
NH4OH
Na3P04
Basicity Factor
1.78
1.35
1.00
1.09*
2.48
1.72
1.25
0.94
#*
0.89
##
2.94
1.43
0.92
#Grams of Calcium Carbonate (CaCO3) equivalent per gram of agent.
##Basicity factor will vary depending on cations present in the acid mine
drainage.
Revised from Hill,
-129-
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After treatment with calcium alkalis, the effluent has a higher hard-
ness, may have a sulfate concentration up to 2, 000 ppm, and may contain
significant amounts of suspended solids depending on the solids separation
technique. To the extent that acidity is removed and the soluble iron con-
centration reduced, neutralization with calcium based alkalis is successful.
The use of sodium based alkalis, such as soda ash and caustic soda,
will effect a removal of acidity and iron. However, these alkalis are sub-
stantially more expensive to use. There is a major technical difference
though, since sodium sulfate is a highly soluble salt, there is no reduction
in sulfate content. The insoluble materials are iron and aluminum hydrox-
ides and oxides and the volume of precipitates is less since sulfates are not
removed from solution. The use of sodium based alkalis, however, does
no!; add to effluent hardness as in the case of calcium based alkalis.
Many other alkaline materials could be used to neutralize acid mine
drainage, but because of higher costs without commensurate advantages,
these materials have not been used in other than laboratory experiments or
small scale demonstration projects.
Coal mine drainage with a low pH, net acidity and dissolved iron can
be neutralized with alkalis such as hydrated lime, limestone, caustic soda
and soda ash. The neutralization process removes acidity and reduces the
soluble iron concentration. The efficiency of the neutralization process de-
pends on the alkali used, methods of application and the characteristics of the
mine drainage.
The use of calcium alkalis, such as lime, hydrated lime and limestone
will remove sulfate ions if the solubility product of calcium sulfate is exceed-
ed. If neutralization is accompanied by aeration or other methods of oxidation,
soluble iron salts will be removed as insoluble hydrated iron oxides. Thus,
effluent solutions from such neutralization processes generally have no acid-
ity or slight alkalinity, contain low concentrations of soluble iron, and have
reduced sulfate concentrations if the original sulfate concentration exceeded
about 2,000 ppm as calcium sulfate. Soluble aluminum salts are also re-
moved from solution as precipitates of aluminum hydroxide.
Neutralization historically has been applied to Class I and II mine
drainage (Table 1). Unslaked lime, hydrated lime and more recently lime-
stone have been more widely used for neutralization, primarily because of
lower costs.
Although neutralization and oxidation processes remove acidity and
iron salts from acid mine drainage, significant technical problems exist in
separating the precipitated solids. The sludge produced is characteristically
difficult to filter and dewater. Sludge disposal is a serious consideration,
since it is a pollutional waste. Disposal methods now in use include lagooning
and disposal in abandoned dry mines. Accurate sludge handling and disposal
-130-
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costs have not been detailed well in the literature, although much information
is available regarding the methods of sludge disposal and the factors involved
in the consideration of each of these methods.
Chemistry of Lime Neutralization
Quick lime (CaO) and hydrated lime (Ca(OH)2) have been used in the
treatment of acid mine drainage. These limes may be either high-calcium
or high-magnesium (dolomitic). The reactions of lime with acid mine drain-
age are illustrated in equations (6) through (10).
CaO + H2O—— Ca(OH)2 (6)
Ca(OH)2 + H2SO4 -CaS04 + 2 H2O (7)
3 Ca(OH)2 + A12(SO4)3 —3 CaSO4 + 2 A1(OH)3 (8)
Ca(OH)2 + FeSO4 Fe(OH)2 + CaSO4 (9)
3 Ca(OH)2 + Fe2(S04)3 —2 Fe(OH)3 + 3 CaSO4 (10)
In addition to increasing the pH and decreasing the acidity, lime treat-
ment will remove many of the metallic salts. Figures 1 and 2 show the solu-
bility of aluminum, iron and manganese at various pH's. Aluminum and
manganese will precipitate if the proper pH level is reached. Calcium sulfate
will increase the hardness of the water until its maximum solubility is reached
(approximately 2, 000 rng/1), then it will precipitate. Ferrous hydroxide has
a low solubility, which decreases as the pH increases. Ferric hydroxide is
even less soluble and its solubility decreases at higher pH's. The oxidation
of ferrous iron results in a decrease of the pH, which may result in an in-
crease of the iron concentration because of the higher solubility of iron at
lower pH's.
The addition of an alkaline agent will result in the conversion of ferrous
sulfate to ferrous hydroxide and increase in pH. At the higher pH iron II will
oxidize rapidly (Figure 3) to form insoluble ferric hydroxide. Holland, et el.' ',
used lime in treating a mine discharge with high acidity and iron concentrations
and found that a. pH of 10.5 was needed to assure complete iron removal.
Chemistry of Limestone Neutralization
When iron sulfate salts are dissolved in a wa^.er medium the compounds
undergo hydrolysis reactions to liberate the hydrogen ion. Hydrolysis is de-
fined as a reaction of an ion with water to form an associated species plus H+
or OH . The general equation for a cationic hydrolysis is:
-131-
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FIGURE I
SOLUBILITY OF ALUMINUM, IRON AND MANGANESE
IN ACID MINE DRAINAGE AT VARIOUS pH's
Sample Source:
Deep Mine.Elkins.W.Va.
From Hill,
-220
0
10 12 14
-13Z-
-------
FIGURE 2
SOLUBILITY OF IRON
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I
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10
I
12
After O'Melia and Stumm, I967(82)
-133-
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FIGURE 3
1
-2
o
o
-1 -3
-4
-5
Stumm-Lee Law
K1'
•d log fFe (1)1
dt
Singer- Stumm
Modification
2345
PH
IRON (II) OXIDATION RATE AT pH 2-7
After Singer and Stumm, 1968
From Hill, 1968<1)
(83)
-134-
-------
M+ + H20 ZHir MOH + H+ (11)
In the case of iron salts the reactions would be:
For ferrous iron
Fe+2 + ELO ^ITZ FeOH+ + H and (12)
C*i
FeOH+ + H20 Z^n Fe(OH)2 + H+ (13)
The net reaction would be
Fe+ + 2 H2O ^=±T Fe(OH)2 + 2 H+ (14)
For ferric iron
Fe+3 + H20 I^= Fe(OH)+2 + H+ (15)
Fe(OH)+2 + H2O TT~^ Fe(OH)2+ + H+ (16)
Fe(OH)2+ + H2O^=^Fe(OH)3 + H+ (17)
The net reaction being
Fe+3 + 3 H2O . ' Fe(OH)3 + 3 H+ (18)
These are equilibrium reactions and will go to completion (i.e. com-
pletely hydrolyzed) only if the hydrogen ion is pulled out of the equilibrium.
This can be accomplished by neutralizing the hydrogen ion. with a base.
Calcium carbonate in an acidic medium will undergo a reaction to
form lime and carbon dioxide according to the equation:
CaCO3 + H2O — "- CaO + H2CO3
_ _ (19)
where H2CO3 ^~~" H2O + CO2
The lime will react with the hydrogen ion of the acid to neutralize it
and form water plus the calcium salt of the acid.
CaO + 2 H+ - — Ca++ + H2O (20)
For the case of ferric sulfate, the reactions would be
3 CaO + 2 H+ + SO4~ - — CaSO4 + H2O (21)
+++ = + - — e
(22)
2 Fe + 3 SO4= + 6 H + 6 OH" - — 2 Fe(OH), I
I _ ^
+6 H+ + 3 S0"
-135-
-------
The reaction of calcium carbonate with acidic water to form calcium
oxide, as an intermediate product, occurs at approximately pH 7 or lower.
As the CaO reacts with free hydrogen ions (Equation 21), a resultant increase
in .hydroxal ions occurs.* This in turn results in attachment of a sufficient
number of hydroxal ions (OH ions) to the ferric iron for precipitation of fer-
ric hydroxide to occur, as indicated in Equation 22. In this reaction hydroxal
ions are removed from solution by precipitation, and therefore, free hydrogen
ions are released. These additional hydrogen ions are then neutralized accord-
ing to Equation 21. The reaction of ferric iron in the above equations to form
ferric hydroxide is essentially complete at pH 3.5.
In the case of mine waters high in ferrous iron, the addition of an alkali
will precipitate all iron directly as ferrous hydroxide, Fe(OH)2, only if a pH
of 8.5 to 9.5 is reached. Since C&CO% is practically insoluble in neutral solu-
tions, precipitation of ferrous iron by addition of limestone (CaCO^) will not
occur. If lime instead of CaCO3 is used then the pH will rise to about 10 and
all of the ferrous iron will precipitate.
It is obvious from the above chemistry, that ferrous iron must be oxi-
dized to ferric iron with the formation of free acid before calcium carbonate
can react to neutralize the mine water and precipitate all iron.
*In all aqueous solutions any decrease in hydrogen ion concen-
tration must result in an increase in the hydroxal ion concen-
tration since the product of the two is a constant.
Neutralization of Mine Drainage with High Ferrous Iron Content
Extensive work has been accomplished in neutralization of acid mine
drainage with high ferrous iron content. The following methods will be ex-
plored for their feasibility and cost:
1. BCR limestone treatment process.
2. U.S. Bureau of Mines limestone treatment process.
3. Combination lime stone-lime treatment process.
4. Combination lime-lime stone neutralization with rotary precoat filtration
for sludge dewatering.
5. Electrochemical oxidation followed by limestone neutralization.
6. Ozone oxidation followed by limestone neutralization.
7. Biochemical oxidation followed by limestone neutralization.
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BCR Limestone Treatment Process
As a result of extensive bench-scale tests, Bituminous Coal Research,
Inc. ' ' ', has developed a process whereby coal mine drainage containing
ferrous iron can be treated with limestone. The process results in complete
neutralization of acidity and removal of iron to acceptable limits.
The BCR limestone treatment process consists of the following unit
operations in sequence: a) Mine drainage holding or equalization, b) adding
pulverized limestone and mixing, c) aerating, d) slurry recirculation to the
mixing area, e) sludge settling, and f) sludge dewatering and disposal.
A general concept of the limestone neutralization process is shown in
Figure 4, The individual parts of the total system are: a) holding tank, b)
pulverized limestone storage tank, c) limestone feeder, d) limestone reactor,
e) aerator, f) settling tank, g) optional sludge recirculation, h) optional oxi-
dation catalyst, and i) optional coagulant aid.
Advantages of Using Limestone
1. Lower costs per unit weight of chemical reagent necessary to
neutralize the same quantity and quality of coal mine drainage.
2. Fewer safety problems in handling a less reactive reagent.
3. A less harmful effect on the body of water receiving the effluent
in case of accidental overtreatment.
4. A reduction in sludge volume and an increase in sludge solids
content. The volume of sludge from limestone treatment can
be as little as one-fifth of that obtained in lime treatment, and
the solids content can be almost 15 times greater. The re-
duction in sludge volume allows for the use of smaller settling
basins, and this may be sufficient reason for selecting lime-
stone treatment over lime in areas where space is at a premium.
Disadvantages of Using Limestone
1. The major disadvantage of the process is the slow rate of oxida-
tion of ferrous iron at the relatively low pH attainable with lime-
stone. Long detention time and, consequently, large tanks are
required for mixing the mine water with limestone and for aerating
until most of the ferrous iron has been oxidized. This results in
higher costs, inefficient mixing, diffusion of oxygen, and sparging
of carbon dioxide.
-137-
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FIGURE 4
Sludge
Recirculation
(Optional)
Coal
Mine
Water
Holding
Tank
Limestone
Reactor
D
Aerator
E
Settling
Tank F
Pulverized
Limestone
Storage
Tank
Limestone
Feeder
C
Oxidation
Catalyst H
(Optional)
Coagulant Aid j
(Optional)
Treated Water
To
Receiving Stream
Sludge To
Disposal
FLOW DIAGRAM OF
CONCEPTUAL LIMESTONE TREATMENT PROCESS
From Bituminous Coal Research, Inc. , 1971
(5)
-138-
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2. The production of fine particles in the effluent which do not settle
rapidly may require coagulant aids for their removal.
3. The availability of finely divided limestone of the desired quality.
To be used in the treatment process, the particle size of the limestone
should be at least 74 microns (200 mesh) and preferably smaller. In addition,
the limestone should approach pure calcium carbonate in composition with as
low a content of magnesium as possible. Magnesites are the least effective
neutralizing agents, followed closely by dolomitic limestones.
Coal mine waters containing ferrous iron in quantities as great as 5, 000
mg/1 present particular problems in treatment which have not been solved.
Treatment of such mine waters results in precipitation of calcium sulfate (gyp-
sum) during treatment with resultant scaling problems on tanks, pipes, mixers,
aerators, and pumps. Also, the volume of sludge would be greater than the
volume of treated water obtained. These two problems are inherent in both
limestone and lime treatment.
The laboratory studies demonstrated feasibility of the limestone treat-
ment process using laboratory-scale pilot plant apparatus, delineated the in-
dividual operations and sequence of operations necessary for adequate treatment,
and established basic information pertinent to engineering design of full-scale
treatment plants. Based on the results of these studies, experimental results
were related to engineering design of full-scale treatment plants. For these
engineering evaluations, flows of 0.1, 1.0, and 7.0 million gallons per day
(mgd) were chosen and data developed for construction and operation of plants
to treat discharges having these flows. The EPA Class I mine drainage was
chosen as the quality of mine water to be used in the evaluations, because that
type of mine drainage would present the greatest problems in treatment.
The following three cases of the Class I mine drainage were used to
develop the flow schematics, unit designs, and material balances:
Case A; Acidity, mg/1 (as CaCO3) 1,000
Ferrous iron, mg/1 500
Ferric iron, mg/1 0
Aluminum, mg/1 0
Sulfate, mg/1 1, 000
Case B: Acidity, mg/1 (as CaCO3) 8,000
Ferrous iron, mg/1 5, 000
Ferric iron, mg/1 0
Aluminum, mg/1 500
Sulfate, mg/1 10, 000
-139-
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Case C: Acidity, mg/1 (as CaCO3) 15,000
Ferrous iron, mg/1 10,000
Ferric iron, mg/1 0
Aluminum, mg/1 2, 000
Sulfate, mg/1 20, 000
In addition to the Class I mine drainage, a discharge from the South
Greensburg, Pennsylvania area was used in the laboratory studies and for
the engineering evaluation. The estimated flow of this discharge was 4.0
mgd and the water had the following average quality:
Case D: Acidity, mg/1 (as CaCO3) 190
Ferrous iron, mg/1 90
Ferric iron, mg/1 0
Aluminum, mg/1 8
Sulfate, mg/i 1,200
Cost Evaluation of the Process - The development of cost data for
construction and operation of full-scale mine drainage treatment plants to
treat Class I coal mine drainage is difficult because of the wide range of
flow and quality conditions included in Class I. Furthermore, treatment
plant costs will vary based on the availability of suitable land, soil condi-
tions, and topography of the site. For the cost analysis, it has been assum-
ed that suitable land is available to construct the treatment plant units, the
topography of the proposed plant site is relatively level, the proposed site
does not have a high water table, the depth to bedrock at the proposed site
is a minimum of 10 feet, and soil at the proposed site contains a high clay
content. In addition, it has been assumed the proposed holding basin could
be constructed with a water surface elevation sufficient to produce a gravity
flow condition through the plant complex; therefore, the only pumping re-
quirements would be for recirculation and wasting of sludge.
The treatment facility designed to treat coal mine drainage contain-
ing ferrous iron and using limestone as the neutralizing agent, consists of
the following unit operations, in flow-through sequence: a) holding or equali-
zation lagoon; b) reactor tank; c) aeration tank; d) settling basin, and e)
sludge dewater basin.
The cost evaluation has been based upon the sequence of treatment
units as outlined and the plant operation procedures and assumptions as des-
cribed. The coal mine drainage is conveyed to an earthen holding lagoon
providing a 12 hour retention for the mine water. The holding lagoon design
has a two (2) foot freeboard and 1:1 sidewall slopes with riprap on the upper
sidewalls. To permit monitoring and sampling of the holding basin overflow,
ai open concrete flume connects between the holding basin and reactor tank.
The pulverized limestone and recirculated sludge is added to the reactor
tank and mixed with coal mine drainage for a period of 60 minutes. Rein-
forced concrete reactor tanks are used in order to eliminate the erosion
-140-
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problems caused by mixing action in earthen basins. The reactor tanks are
constructed with vertical walls and a four (4) foot freeboard.
Effluent from the reactor tank flows to an aeration tank where mixing,
aeration and sparging of carbon dioxide are accomplished by mechanical sur-
face aerators. The aeration tanks are sized for a 60 minute detention period
for the total flow rate to the unit. The aeration tanks are constructed of re-
inforced concrete and the aerators are mechanical surface aeration units
which ensure continuous mixing. The aerator is secured with guy wires or
supported by structural steel members spanning the tank walls.
The aeration tank effluent flows into the settling basin, providing a 12
hour detention period based upon the flow rate to the settling basin. The set-
tling basin is provided with an influent distribution trough and weir and de-
signed to minimize the possibility of short circuiting. The earthen basins are
constructed of well compacted clay-type soil to reduce leakage. In addition,
the earthen settling basins are constructed with a minimum of two (2) feet
freeboard, a minimum inside wall slope of 2:1 and riprap on the upper sidewalls
to prevent erosion by the surface wave action. An open channel to the re-
ceiving stream permits visual observation and continuous pH monitoring of the
treated effluent. The sludge from the settling basin is pumped from the set-
tling basin to the sludge pump well.
The sludge removal system has been designed to use portable floating
surface pumps secured to the basin crest by guy wires. Recirculated sludge
is pumped at a rate equal to the plant influent to the reactor tank. The re-
mainder of the settled solids is pumped by the waste sludge pumps to the earth-
en sludge dewatering basins for additional concentration and disposal. All
pumping systems include a standby pumping unit to be used during maintenance
or breakdown.
The construction costs for sludge dewatering facilities are based on
the assumption that basins can be located adjacent to the treatment complex
and do not reflect costs of pumping sludge through a long pipeline. The
supernatant from the dewatering basin is discharged to the receiving stream.
A concrete sump, with pumps and appurtenances to pump the concentrated
sludge from the dewatering basin, provides a means for transfer of the sludge
to tank trucks for ultimate disposal. The dewatering basins have a capacity
to hold a three (3) month sludge accumulation.
The design of the limestone treatment process units is based on single
unit operation and does not reflect the capital costs if duplicate units are re-
quired.
Facilities for a minimum of four (4) days storage of bulk pulverized
limestone is provided at the plant site. It is assumed limestone will be de-
livered to the plant site by pneumatic unloading trucks. The limestone storage
bins are equipped with level indicators, limestone feeders, and dust collectors.
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The limestone feeders are installed in duplicate to reduce the possibility of
plant shutdown due to mechanical equipment failure and to permit routine
maintenance on the equipment. This equipment should be located near the
reactor tank in order to reduce distance of conveying limestone.
A control building is required at the plant site to house the plant ser-
vices, administration facilities, and chemical feed systems. The plant ser-
vices and administration section of the control building should contain 1 ) an
office for the plant operator; 2) a central control panel from which the treat-
ment plant operations would be monitored; 3) laboratory facilities for water
quality analysis and chemical dosage controls; 4) main motor control center,
and 5) maintenance shop. The chemical feed equipment section of the con-
trol building contains the limestone and coagulant aid feed equipment.
A paved access roadway should be constructed to the plant site to en-
sure delivery of the chemicals to the plant during all weather conditions.
The operation and control of the proposed mine drainage treatment
complex is based upon the flow rate and acidity concentration of the specific
mine drainage discharge to be treated. The holding basin effluent flow should
be continuously and automatically metered. Acidity concentration at this point
in the process must be manually sampled and analyzed to determine the quan-
tity of limestone feed. In addition, the pH should be continuously and auto-
matically monitored by pH probes located between the aeration tank and settling
basin and in the treated water discharge channel. The recirculated sludge
flow shoald be automatically regulated by the plant influent flow rate at the
ratio of 1:1.
The following assumptions are made for the purpose of completing
plant design data and material balances:
1, The limestone requirement is twice the stoichiometric amount based on
acidity.
2. A recirculated sludge to mine drainage feed ratio of 1:1 is required.
(Actually, a 1:1 ratio of slurry to coal mine drainage. )
3. Twenty five percent of the limestone feed remains unreacted in the sludge.
4. All but 7 mg/1 of the initial iron present is precipitated in the sludge as
ferric hydroxide.
5. All of the initial aluminum is precipitated in the sludge as aluminum
hydroxide.
6. Calcium sulfate (gypsum) is not precipitated in the sludge.
7. The sludge solids content is five percent.
-142-
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8. The sludge specific gravity is 1.05.
The cost parameters on which Bituminous Coal Research, Inc. based
their costs of limestone treatment are given in Table 3. The costs are up-
dated using Engineering News-Record (ENR) Construction Cost Index. It is
assumed the cost index was 1575 when BCR made their cost estimates (June,
1971) and the updated costs are based on the estimated April, 1972 ENR cost
index of 1700. The updated cost estimates are plotted in the form of cost
carves (Figures 5 to 15).
Table 4 presents an estimate of capital cost for a limestone treatment
plant to treat South Greensburg coal mine drainage at a 4. 0 mgd flow rate.
The total capital cost of the plant based on June, 1971 prices is estimated at
$658,960. Using the April, 1972 ENR cost index, the total capital cost of the
plant is $711, 000.
Figures 6 through 9 give the estimated costs for various plant facilities
based on plant capacity and chemical characteristics 01 the mine drainage to be
treated. The cost of site clearing, final grading, access roads, engineering and
contingencies should be added to arrive at the total plant costs which are indi-
cated in Figure 5.
The operating costs for plants of various capacities and chemical char-
acteristics of mine drainage to be treated are indicated on Figure 10. Figures
11 through 14 give cost estimates for various elements of plant operation and
Figure 15 is an estimate of sludge accumulation for one year for various size
plants with differing chemical characteristics of mine drainage. The costs of
coagulant aids, if needed, and contingencies should be added to obtain the esti-
mated total operation cost of the treatment plant.
The BCR limestone process should be studied on a larger scale since
bench scale studies have not sufficiently defined the following:
1. The mixing requirements in the reactor tank
2. The cost of grinding coarse limestone versus the use of pulverized lime-
stone
3. The use of mechanical aerators
4. The sludge recirculation ratio in an equilibrium condition and the effect
of sludge properties such as solids content, alkalinity, etc. on process
efficiency
5. The effect on treatment plant systems in treating coal mine drainage having
sulfate concentrations of up to 20, 000 mg/1 with resultant precipitation of
gypsum
6. The effect of coagulant aids on settling properties and on recycled sludge
7. The effect of more concentrated coal mine drainage on sludge volume.
-143-
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TABLE 3
BASIS FOR ESTIMATED COSTS OF LIMESTONE TREATMENT
VARIOUS SIZE TREATMENT PLANTS
1. Capital Costs
The capital costs are amortized for twenty (20) years at six (6) percent
interest.
2. Labor
a. 0. 1 MGD Treatment Plant:
1 Operator $ 7, 500. 00
1 Part Time Laborer 3, 003. 00
$10,500.00
b. 1.0 MGD Treatment Plant:
1 Operator $ 8, 000. 00
1 Laborer 6,000.00
$14,000.00
c. 7.0 MGD Treatment Plant:
1 Operator $10, 000.00
2 Laborers 15,OOP.00
$25,000.00
d. 4. 0 MGD Treatment Plant:
1 Operator $10,000.00
1 Laborer 7,5_OQ.Oj)
$17,500.00
3. Limestone
(Pulverized limestone delivered to plant site by bulk trucks.)
0 to 10 tons/yr - $7. 00 per ton
10 to 20 tons/yr - $6.50 per ton
Greater than 20 tons/yr - $6.00 per ton
4. Coagulant Aid
$2.00 per pound
5. Powe r
a. 0. 1 MGD Treatment Plant: $85. 00 per horsepower per year
b. 1.0 MGD Treatment Plant: $80.00 per horsepower per year
c. 4.0 MGD Treatment Plant: $80.00 per horsepower per year
d. 7.0 MGD Treatment Plant: $75.00 per horsepower per year
6. Maintenance and Repairs
a. 0. 1 MGD Treatment Plant: $ 3,000 per year
b. 1.0 MGD Treatment Plant: $ 5, 000 per year
c. 4.0 MGD Treatment Plant: $ 8, 000 per year
d. 7. 0 MGD Treatment Plant: $10, 000 per year
7. Contingencies
One percent of construction costs
8. Sludge Disposal Cost
$10.00 per 1,000 gallons
-144-
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TABLE 4
ESTIMATE OF CAPITAL COST FOR LIMESTONE TREATMENT PLANT
SOUTH GREENS BURG COAL MINE DRAINAGE
4.0 MGD FLOW RATE
1. Site Preparation
a. Clearing & Grubbing $ 500.00
2. Structures
a. Holding Lagoon 76,000.00
b. Reactor Tank 43, ZOO. 00
c. Aeration Tank 43,200.00
d. Settling Basin 118,500.03
e. Sludge Dewatering Basin 35,000.00
f. Sludge Pump Well 12,000.00
3. Control Building 48,000.00
4. Mechanical Equipment
a. Mixers 25,500.00
b. Aerators 31,000.00
c. Sludge Recirculation Pumps 11,250.00
d. Waste Sludge Pumps 1,950.00
e. Settling Basin Sludge Pumps 11,250.00
5. Chemical Feed Equipment 6,000.00
6. Mechanical Piping 40,000.00
7. Control Equipment 24,000.00
8. Access Roadway 2,500.00
9. Final Grading 6,000.00
10. Electrical 30,000.00
11. Contingencies 56,150.00
12. Engineering 36, 960. 00
TOTAL CAPITAL COSTS $658, 960. 00
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FIGURE 5
ESTIMATE OF CAPITAL COSTS Vs. PLANT CAPACITY
BCR LIMESTONE TREATMENT W/SLUDGE DEWATERING
EPA.WQO, CLASS I COAL MINE DRAINAGE (REF5)
0.1
02
0 3 O.4 05
10 2O
CAPACITY-MGD
30 40 5.0
-146-
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FIGURE 6
ESTIMATE OF CAPITAL COSTS Vs. PLANT CAPACITY
BCR LIMESTONE TREATMENT W/SLUDGE DEWATERING
EPA,WQO,CLASS I COAL MINE DRAINAGE (REF. 5)
1000
O.I 0.2 0.3 0.4 0.5 1.0 2.0 3.0 4.0 5.0 10.0
CAPACITY-MGD
-147-
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FIGURE 7
ESTIMATE OF CAPITAL COSTS Vs. PLANT CAPACITY
BCR LIMESTONE TREATMENT W/SLUDGE DEWATERING
EPA.WQO.CLASS I COAL MINE DRAINAGE (REF5)
10,000!
5,000
4,000
3,000'
SLUDGE REtitoULATING
CASE A
WASTE SLUDGE PUMPS ( CASE B
CASE C
01 02 03 04 05 1.0 20 30 40 50
CAPACITY-MGD
-148-
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FIGURE 8
ESTIMATE OF CAPITAL COSTS Vs. PLANT CAPACITY
BCR LIMESTONE TREATMENT W/SLUDGE DEWATERING
EPA,WQO,CLASS I COAL MINE DRAINAGE (REE5)
1,000
i) (2) (3) SETTLING BASIN
41 CONTROL BUILDING
5) (6) (7) SLUDGE PUMP WELL
®,(D,® CHEMICAL FEED EQUIPMENT
CONTROL EQUIPMENT
I 1 ._! 1 .1 I
0.2
0.3 0.4 0.5 1.0 2.0
CAPACITY-MGD
3.0 4.0 5O
10.0
-149-
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FIGURE 9
ESTIMATE OF CAPITAL COSTS Vs. PLANT CAPACITY
BCR LIMESTONE TREATMENT W/SLUDGE DEWATERING
EPA.WQO.CLASS I COAL MINE DRAINAGE (REF5)
1,000
500
400
300
200
CO
cc
100
CO
Q
50
co 40
O
X 30
co
O
O
2
0.
o
20
10
-MECHANICAL PIPING:CASE
O.I 0.2 0.3 04 0.5 1.0 2.0 3.0 4.0 5.0 10.0
CAPACITY-MGD
-150-
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10.0
O.I
FIGURE 10
ESTIMATE OF OPERATING COSTS Vs. PLANT CAPACITY
BCR LIMESTONE TREATMENT W/SLUDGE DEWATERING
EPA.WQO.CLASS I COAL MINE DRAINAGE (REF5)
0.1
0.2 03 04 05
3.0 4O 5.0
10.0
CAPACITY-MGD
-151-
-------
I
8
_l -I
999
o o o
^t.
O Z> "" <
< O CO QL
o
o
8
s
s
ii
s§
uj
UJ
or
o
m
-152-
-------
FIGURE 12
ESTIMATED COSTS (CENTS/THOUSAND GALLONS)
BCR LIMESTONE TREATMENT W/SLUDGE DEWATERING
EPA,WQO,CLASS I COALMINE DRAINAGE(REF5)
500
400
1S\f\
ER TREATED
5 i_J
u.
O
g 50
0 40
•J
4 30
0
z
COST-CENTS/THOUS/!
— ro ex -fc 01 o c
1
• •
=K
i^iH
cc
)S
CAS
*f\
c
E C
C Q
ASE
T
0
F
" —
LIMESTC
— —
)NE
«==
——
•—
•~m
0.1
1.0
CAPACITY-MGD
10.0
-153-
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FIGURE 13
ESTIMATED COSTS (CENTS/THOUSAND GALLONS)
BCR LIMESTONE TREATMENT OF
EPA,WQO,CLASS I COALMINE DRAINAGE (REF.5)
100.0
POWER-CASE B
POWER-
0.1
02
0.3 040.5 ID 2.0
CAPACITY-MGD
3.0 4.0 5.0
-154-
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FIGURE 14
ESTIMATED COSTS (CENTS/THOUSAND GALLONS)
BCR LIMESTONE TREATMENT OF
EPA.WQO, CLASS I COAL MINE DRAINAGE (REF5)
1000
500
400
300
Q
£ 200
Q:
I-
2] 100
O
CO 50
3 40
_l
% 30
< 20
CO
CO 10
O
8
4
3
2-
CASE B
;ASE c-
SLUDGE DISPOSAL COSTS
CAPITAL COST
I
0.1 02 0.3 0.4 0.5 1.0 20 30 4.0 5.0 100
CAPACITY-MGD
-155-
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FIGURE 15
ipoo
LJ
Lu
LU
O
5
LU
LU
Q
O
O
§
§
300
100
10
1.0
ESTIMATED SLUDGE ACCUMULATION IN ONE YEAR
FROM BCR LIMESTONE TREATMENT OF
EPA.WQO,CLASS I COAL MINE DRAINAGE (REF5)
/
O.I 02 0.3 04 05 1.0 2.0
CAPACITY-MGD
3.0 4.0 5.0
10.0
-156-
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U. S. Bureau of Mines Limes tone _T r e atment Pro cess
The U. S. Bureau of Mines initiated an effort in 1966 to develop a
low-cost practical neutralization process for treatment of acid mine water.
The emphasis was on using limestone as the neutralizing agent because of
its low cost and availability. As a result of their effort ' ' '• » '• ', a
limestone neutralization process was developed to treat mine water of any
quality and preliminary plant design and total cost estimates were develop-
ed.
The general process for treatment of acid mine water effluent con-
sists of limestone neutralization, aeration, solids settling, and sludge con-
centration. Figure 16 is a flow sheet of the mine water treatment process.
From mine
Sludge settling
and
storage ponds—/
Automatic k—'
control fcH
Treated
effluent
FIGURE 16
FLOWSHEET OF MINE WATER TREATMENT PROCESS
After Mihok, 197()(8)
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Mihok^ ' describes the process as follows:
Gravity flow in this plant design is utilized throughout the treatment
from holding pond to ultimate effluent discharge. Mine water flows from the
holding pond through pipes and flumes and is mixed with limestone slurry
generated in an autogenous tube mill or grinder. The resulting mixture enters
the primary section of the aeration pond where air is applied to remove CC>2
formed from the neutralization of free acidity. As the mixture flows into the
main section of the aeration pond, additional limestone slurry is added to
neutralize the remaining acidity formed by oxidation and precipitation of iron.
Air sparging is continued at a reduced rate through the main section of the
aerating pond. The neutralized mixture flows from the pond through flumes
to settling ponds designed to provide sufficient time for the suspended solids
to settle to the bottom of the pond. The clarified effluent is discharged into
a stream or river.
The two settling ponds are designed to hold 10 years of solids accumu-
lation. When the sludge level in the pond approaches within 5 feet of the upper-
most water level, solids settling is conducted in the other pond. Water in the
first pond is drawn off and the sludge is air dried and allowed to remain in
place. When the second pond fills with sludge, the neutralized water is divert-
ed to the first pond which is air dried and settling continues uninterrupted.
Design Criteria and Costs - Design criteria and costs are given for a
wide range of volumes and quality of mine water. Volumes range from 100, 000
gpd to 6 million gpd, acidity from 100 to 5, 000 ppm, ferrous iron from 50 to
1, 500 ppm, and neutralized water suspended solids from 250 to 8,000 ppm.
Suspended solids concentrations typically consist of calcium sulfate, hydrated
metal oxides, silica, unused limestone, and inerts.
Since design criteria and treatment methods affect the cost of construc-
tion and operation of a treatment plant, a discussion of important factors affect-
ing costs follows:
a) Holding Pond - The holding pond capacity is at least three times the
anticipated maximum daily mine water flow. This additional volume provides
safeguards to prevent untreated or inadequately treated water from discharging
into streams or rivers in the event of unforeseen increase of acid mine drain-
age flow and temporary shutdown of neutralizing facilities. It will minimize
fluctuations in raw water feed composition and reduce ferrous iron concentra-
tions.
b) Neutralization Treatment - The limestone autogenous tube mill and
aeration equipment is designed to treat continuously a 25 percent excess of the
anticipated maximum daily mine water acid and ferrous iron load. Process
control is maintained by raw mine water feed regulation. Normal operation
consists of maximum production of limestone for neutralization of total acidity
so that depletion of feed takes place at rated design capacity. When a minimal
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level of acid mine water in the pond is reached, the tube mill shuts down and
is reactivated when sufficient water volume has accumulated.
c) Limestone Storage and Processing - Limestone storage and pro-
cessing capacity is based on the maximum daily total acidity to be treated.
Storage bins are designed to hold at least a five (5) day supply of limestone.
A feeder mechanism is included to meet maximum daily limestone require-
ments. The autogenous grinder provides limestone slurry containing particles
of which 99 percent pass through a 400-mesh screen. A consistent uniform
slurry is produced when the tube mill operates under constant feed and grind-
ing speed coaditioiis.
The storage bin and feeder costs, including installation, have been
obtained from manufacturers of these items.
d) Aeration - Aeration performs three functions in limestone treat-
ment of acid mine drainage; it mixes the reactants, removes CO£ formed
from CaCC>3 reaction with acid, and supplies oxygen for ferrous iron oxida-
tioa. MihokW believes that this can best be accomplished by diffused air or
air sparging.
The design of the aeration system is based on winter operating condi-
tions (air and water temperature 0° to 10° C) when the lowest reaction rates
and highest concentrations of ferrous iron prevail. The volume of acid mine
water, ferrous iron concentration, and oxidation rate under these conditions
dictate the size of the pond and bhe volume of air to be supplied. Disregarding
catalytic oxidation, ferrous iron oxidation rates at pH range of 6. 5 to 7. 5 and
10° C for various concentrations used in this design are as follows:
1
1
2
Fe++
concentrate
50 '
100
250
500
, 000
, 500
, 000
Oxidation
rate,
ppm per min
r 3
4
5
6
7.5
10
12.5
Based on results of the pilot plant and laboratory tests, these rates
can be achieved with air rate volumes approximately double the water volume
flow rate for a. period of up to a five (5) minute detention time in the primary
section of the aeration unit. Subsequent air, at rates approximately equal to
the water volume flow rate, is supplied in the secondary or main section of
the aeration unit. A centrifugal blower delivers air at four (4) psi pressure
at rated capacity through a PVC pipe equipped with diffuser nozzels or orifices
mounted near the bottom of the aeration pond.
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Centrifugal blower, motor, and piping costs have been obtained from
manufacturers and total costs including installation have been estimated.
e) Sludge Settling and Concentration Ponds - Suspended solids are sep-
arated from the treated water by means of duplicate settling ponds. The al-
ternate use of the pond provides for sludge concentration and solids storage in
situ. At least a 24 hour settling time is maintained at all times. Capacity is
based on the volume occupied by air-dried solids accumulated over a period of
10 years. An average bulk density of dried solids of 50 Ibs./cu. ft. has been
used to determine the settling pond capacity. A ton of dried sludge cake con-
taining up to 50 percent moisture occupies the volume of approximately 300
gallons of water.
f) Excavation - Pond construction costs depend on many factors but
ultimately are expressed in terms of cost per cubic yard of earth handled.
The capacity of the pond in gallons equated in terms of cubic yards determines
the relative amount of work that must be performed. An estimate of one dollar
($1.00) per cubic yard for excavation was used in determining construction
costs for holding, aeration, and sludge settling ponds. Aeration pond costs
also include an additional $1.00 per square foot for concrete slab lining of
the side walls.
g) Water Transport, Flow Control, and Measurement - Mine water is
transported by means of open flumes throughout the process, except for water
discharged from the holding pond which flows through PVC pipes. Piping and
valves are incorporated in the system for a distance of 200 feet from pond to
neutralizer. Open, half round, corrugated galvanized pipe flumes carry the
water through the rest of the process. Weirs for measuring water flow are
located ahead of the neutralizer and at the effluent discharge from the settling
pond. Automatic controls are used to regulate the mine water feed instead of
regulating the neutralizing agent feed, because generation of limestone fines
can be controlled more efficiently and economically with constant-speed grind-
ing.
Hydraulic requirements dictate the size of valves, piping, etc., and
the cost of these items was obtained from manufacturers. Included in the total
cost of water transport and control are labor and installation estimates.
h) Limestone Fines Generation at Tube Mill - For limestone require-
ments of up to 10 tons per day, the cost of limestone fines generation is related
to the cost of the pilot plant tube mill designed and constructed by the Bureau
of Mines. Tube mill cost estimates for greater than 10 tons per day capacities
have been obtained from grinding mill manufacturers.
i) Auxiliary Equipment Costs - Included in this item are pH meters,
turbidity meters, and process controls. The cost of these items were obtained
from the manufacturers. Table 5 gives the estimated costs of these items for
treatment plants of various capacities.
-160-
-------
j) Other Factors Affecting Costs - The costs of land acquisition, site
improvement and pumping water from the mine can be highly variable. It is
assumed for this cost estimate that sufficient land is available and mine water
is discharging into the holding or equalization pond. It also has been assumed
that electric power is available at the site.
k) Capital Costs - The total treatment plant capital costs include all
construction costs plus an allowance of 25 percent to cover contingencies.
1) Fixed Costs - Included in the annual operating costs is a. fixed charge
of 10 percent of the total capital costs. It is expected that the useful life of the
plant equipment will be greater than 10 years, but the ponds storage capacity
sets this 10 year limit. The plant life can be extended by removing the solids
from the pond.
m) Operating Costs -
1. Limestone - The cost of limestone (containing about 75 percent
CaCOo) has been set at $2. 00 per ton f. o. b. for these calcula-
tions .
2. Labor - Labor costs are based on $10, 000 per man-year.
3. Powe r - The power cost is based on a 1 cent per kilowatt -hour
rate, with continuous consumption 24 hours per day and 365
days per year.
4. Maintenance - Yearly maintenance costs, including tube mill
liner replacement, are estimated at 10 percent of tube mill
capital costs.
The detailed breakdown of estimated capital and operating costs for
limestone treatment plants of various capacities used in the U. S. Bureau of
Mines publication "Mine Water Research - Plant Design and Cost Estimates
for Limestone Treatment, " 1970, by Mihok ' ' is shown on Tables 6 through
11. The cost estimates presented in these tables were made in 1969. It is
assumed that the ENR construction cost index was 1305 (December, 1969)
when these estimates were made. The estimated costs were updated using an
ENR construction cost index of 1700 (April, 1972), and the updated costs were
plotted as cost curves on Figures 17 through 24.
A preliminary study conducted by the U. S. Bureau of Mines indicates
the aeration step might be supplanted by a catalytic oxidation step prior to
neutralization. Extremely rapid ferrous iron oxidation rates have been attain-
ed with the use of granular activated carbon. With all the iron in the raw mine
water converted to the ferric state, neutralization equilibrium can be quickly
established and subsequent aeration is unnecessary. Promising aspects of the
catalytic oxidation process are nonrecurring expense and long operational life
-161-
-------
of the activated carbon. Therefore, further reduction of mine water treat-
ment costs and greater simplicity and control of neutralization are possible.
Bituminous Coal Research, Inc.* ' in their studies also indicated that
activated carbon is an effective catalyst and reduces the time required for
ferrous iron oxidation to about 60 minutes. However, the short duration (about
24 cycles) for which this activity is maintained requires more frequent regen-
eration of the activated carbon making the process economically unattractive.
TABLE 5
AUXILIARY EQUIPMENT COSTS
Auxiliarv equipment
Piping, valves, etc....
pH meter. ...... ° . <> . . .
Electricity. . 0 .........
Weir and flumes .......
Automatic controls ....
Building .............
Total Cost ....
Plant capacity --gpd
100, 000
$ 1,000
1, 500
1, 500
1, 000
1,500
4, 500
1, 500
$12, 500
300. 000
$ 1,500
1, 500
1, 500
1, 000
1, 500
4, 500
1, 500
$13, 000
500, 000
$ 2, 000
1, 500
1, 500
3, 000
3,000
5, 000
2, 000
$18, 000
1, 500, 000
$ 3,500
1, 500
1,500
3, 000
3, 000
5, 000
2, 000
$19, 500
2. dOO.OOO
$ 5, 000
1, 500
1, 500
6, 000
4,500
6, 000
2, 500
$27, 000
6, 000.000
$ 8, 000
1, 500
1,500
o, 000
4, 500
6, 000
2,500
$30, 000
-162-
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-168-
-------
FIGURE 17
ESTIMATED CAPITAL COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TREATMENT PLANT-US. BUREAU OF MINES (REF8)
IRON AS Fe+*=50 PPM
EXTRAPOLATED CURVE
ICH
QI
02
03 04 0.5
10 20
CAPACITY-MGD
30 40 50
100
-169-
-------
FIGURE 18
ESTIMATED CAPITAL COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TREATMENT PLANT-U.S. BUREAU OF MINES (REF 8)
IRON AS Fe-1"1^ 100 PPM
EXTRAPOLATED CURVE
0 20
CAPACITY -MGD
30 40 50
100
-170-
-------
ipoo-
20-
IOJ
FIGURE 19
ESTIMATED CAPITAL COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TREATMENT PLANT-US BUREAU OF MINES (REF8)
IRON AS Fe++=500PPM
EXTRAPOLATED CURVE
O.I
0.2
0.3 0.4 0.5
1.0
CAPACITY-MGD
2.0
3.0 4.0 5.0
10.0
-171-
-------
10
FIGURE 20
ESTIMATED CAPITAL COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TREATMENT PLANT-US. BUREAU OF MINES (REF8)
IRON AS Fe++=1000PPM
Ql
20 30 40 50
10.0
CAPACITY-MGD
-172-
-------
FIGURE 21
ANNUAL OPERATING COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TREATMENT-U.S. BUREAU OF MINES (REF8)
IRON AS FE++=50 PPM
70r
60-
co
EXTRAPOLATED CURVE
0.2
0.3 0.4 0.5
1.0 2.0
CAPACITY-MGD
30 40 50
10.0
-173-
-------
FIGURE 22
ANNUAL OPERATING COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TREATMENT-U.S. BUREAU OF MINES (REF8)
IRON AS FE++ = IOOPPM
70r
60r
EXTRAPOLATED CURVE
0.2 0.3 0.4 0.5 1.0 2.0 3.0 4.0 5.0
CAPACITY-MGD
10.0
-174-
-------
FIGURE 23
ANNUAL OPERATING COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TREATMENT-U.S. BUREAU OF MINES (REF 8)
IRON AS FE++=500PPM
70r
60-
co
O
EXTRAPOLATED CURVE
0.2
0.3 0.4 05
1.0 2.0
CAPACITY-MGD
30 4.0 5.0
10.0
-175-
-------
FIGURE 24
ANNUAL OPERATING COSTS Vs. PLANT CAPACITY
FOR LIMESTONE TRE AT MEN T-U.S. BUREAU OF MINES (REF 8)
IRON AS FE++=1000 PPM
70r
60-
-------
Combination Limestone - Lime Treatment Process
The major disadvantages of using limestone as a neutralizing agent in
treating acid mine drainage are:
1. The relatively inefficient reaction rate, which in many cases,
makes lime more economical to use, and
2. The pH's in excess of 7 which are necessary for rapid oxidation
of ferrous iron are not produced.
Thus, in spite of recent work to increase the reaction efficiency of
limestone, it can only effectively compete with lime when treating ferric iron
mine drainage or mine drainage in which the ferrous iron can be cheaply oxi-
dized to ferric iron by biological oxidation or other methods prior to lime-
stone neutralization.
The logical step would be to combine the limestone and lime processes.
Since limestone is highly reactive at low pH's, it should be added first to the
acid mine drainage. Lime being highly reactive to pH 9 and higher, should be
used to "polish" the limestone treated water. In this manner, combination
limestone - lime treatment enables both limestone and lime to be employed as
neutralizing agents in their most efficient ranges of reactivity. The lower
cost of limestone and the improvement in sludge characteristics as a result
of using this material are advantages which should lead to an overall cost re-
duction when both limestone and lime are employed in neutralizing acid mine
water.
This approach was investigated by the Environmental Protection Agency^ '
at the Norton Mine Drainage Field Site, Norton, West Virginia. The mine drain-
age used in the batch scale studies and in the later pilot plant operation was from
a heavily polluted stream in which it is estimated that 90 percent of the flow is
from abandoned mines; about 70 percent of the pollution flows directly out of
underground mines. The mine drainage has the following significant chemical
characteristics:
Mean
pH 2.5 to 3.4 2.8*
Acidity 134 to 640 mg/1 430 mg/1
Calcium 18 to 170 mg/1 106 mg/1
Magnesium 21 to 120 mg/1 35 mg/1
Aluminum 18 to 69 mg/1 33 mg/1
Sulfate 76 to 1200 mg/1 590 mg/1
Total Iron 14 to 170 mg/1 92 mg/1
*Median Value
Virtually all the iron present in this mine drainage was in the ferric
state.
-177-
-------
In order to obtain the smallest particle size commercially available,
the "rock dust" form of limestone was used. The cost of the limestone was
$6 per ton and lime was $18 per ton.
The combination limes tone-lime treatment provided greater than 25
percent reduction in material cost for treatment to pH 6.5 of the Norton acid
mine drainage as compared to straight lime or limestone treatment. In add-
ition to the materials cost advantage, combination treatment produced a
sludge whose solids contents were up to five times higher than sludge produced
by lime neutralization, though not as high as sludge from limestone neutrali-
zation. The volume of sludge produced by combination treatment was roughly
one-third that of lime treatment and slightly less than limestone sludge volume.
Although the study was performed on ferric iron water, the combination
limestone-lime treatment should be applicable to virtually all acid mine drain-
age situations. Whether or not an economic advantage can be realized is a
matter which can only be determined by evaluating each individual site and its
required process parameter. The variables which must be considered are:
1. Raw material costs of "rock dust" limestone and hydrated lime.
2. Effectiveness of limestone in acid mine drainage treatment
(composition of limestone).
3. Reaction time.
4. Treatment pH
To determine the effects of raw material costs for lime and limestone
on process economics, the data on Table 12 was chosen by Wilmoth, et. al. ^ '
as an example. Both the lime and limestone raw material costs were varied
and the cost reduction calculated. Their plot of the resulting data is shown on
Figure 25. When the lime /lime stone raw material cost ratio is less than
1.8:1, the cost advantage of combination treatment over lime treatment no
longer exists. As the lime/limes tone ratio increased, so did the advantage
of combination, treatment.
In an example, they assumed the water treated in Table 12 was all fer-
rous iron mine drainage and a pH in the range of 9. 0 would be required for
efficient oxidation by aeration. In this example, roughly 20 percent more lime
would be required (verified by titration tests) to affect the pH increase from
6.4 to 9.0. Thus, side 2 in Table 12 would require an additional 0.727 Ibs./
1, 000 gallons of lime (20% of 3.634) for a total of 4. 361. The amount of lime-
stone required by side 1 would not change but the amount of lime would be
increased by the same 0. 727 pounds to 2, 078 Ibs. /I, 000 gallons of water. The
cost reduction due to combination treatment would decrease to 21.4 percent
(lime/limestone raw material cost ratio of 3:1 when limestone = 0. 30/lb. and
lime = 0.90/lb.)
-178-
-------
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-179-
-------
If 70 percent more lime were required to increase the pH from 6.4
to 9. 0, then the cost advantage of combination treatment over lime would
decrease to 15. 1 percent (lime/limestone raw material cost ratio of 3:1).
The combination treatment appears to offer nearly as great an eco-
nomical advantage in ferrous iron situations as in ferric ones. Although
combination treatment requires a higher initial investment in equipment, it
appears the advantage realized in reagent cost reduction can quickly offset
this increased initial expenditure.
2.000
- 1.500
CO
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0.500
FIGURE 25
LIME/LIMESTONE COST RATIO AND PROCESS COST REDUCTION
Z
ui
u
50%
Z
o
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38%
30%
25%
13%
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(-24%)
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LIME/LIMESTONE RAW MATERIAL COST RATIO
u
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After Wilmoth,et al., 1972
(u)
-180-
-------
Combination Lime-Limestone Neutralization with Rotary Precoat Filtration
for Sludge Dewatering
The combination lime-limestone neutralization process was employed
M 9 1 "2 \ J
by Davis, et, al. , I ' ' in conjunction with rotary precoat filtration for de-
watering the sludge produced from neutralization of mine drainage. Pilot
plant operation was performed at five sites. A schematic flow-diagram of the
process used at Hollywood, Penisylvania, the fourth site, is shown in Figure
26. The raw water was obtained from the pump well of the Proctor 2 pumping
station feeding the Hollywood, Pennsylvania experimental mine drainage treat-
ment facility. The chemical characteristics of the mine drainage treated at
this site are: pH - 3. 0, total iron - 653 mg/1, ferrous iron - 445 mg/1, total
acidity - 1, 560 mg/1 and total solids - 4, 110 mg/1.
The pilot plant treatment system was fabricated from the following
equipment:
1. U.S. Bureau of Mines' four foot diameter by 24 foot long tube mill' ' which
was used to produce a fine limestone slurry from one-half to two inch rock.
2. The Pennsylvania Department of Environmental Resources' Operation Yellow-
boy Trailer. This trailer contains a variable capacity feed pump, a 50 gallon
flash mixer with agitator and screw feeder, a. 1,200 gallon agitated aerator
tank with a 17 cfm blower-sprayer unit, a 1, 000 gallon thickener, and a
variable speed sludge recycle/discharge pump.
3. A Johns-Manville rotary vacuum precoat filter (6 inch face and 36 inch
diameter) with a variable speed drum drive, variable speed knife advance
and 30 and 50 percent submergence ports in the filter bowl.
(13'
The conclusions reached as a result of this investigation1 '
were:
1. The sedimentation and filtration unit processes were found to be the major
factors contributing to treatment costs for systems using chemical neutra-
lization followed by solids concentration and dewatering via rotary vacuum
precoat filtration.
2. The optimum economic system design for a given chemical process can
be found by optimizing the individual unit processes with the exception of
the sedimentation and filtration processes. Due to the interaction between
these processes, they should be considered as a single-unit process in
optimizing the design of the system.
3. The use of polyelectrolytes appeared to offer an economic means of in-
creasing sludge concentration, thereby reducing the sludge volume and the
respective filtration costs.
-181-
-------
CO
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-18Z-
-------
4. The presence of unreacted limestone appeared to enhance the settleability
and filterability of the sludge.
5. Chemical neutralization with a combination of limestone and lime offers a
definite cost advantage over lime alone and operational advantages over
limestone alone.
6. Production of fine limestone slurry by attrition of rock in a wet mill on-
site appeared to be the most economical method for feeding limestone.
7. Optimum conditions for operation of the rotary vacuum filter are a drum
speed on one revolution per minute, 30 percent submergence, a CELITE 501*
precoat and a knife advance of 0. 001 inches per drum revolution.
*A proprietory diatomaceous earth filter.
Cost estimates based on the system shown in Figure 26 are presented
in Tables 13 and 14. These cost estimates were computed from values found
in the literature and updated to 1970 economics by use of the Marshall and
Stevens Equipment Cost Index. For this study, it is assumed the updated cost
estimates were equivalent to an ENR Cost Index of 1425 (1970) and they are
further updated to reflect an ENR Cost Index of 1700 (April, 1972). The 1972
cost estimates were plotted and the resulting curves are shown on Figures 27,
28 and 29.
-183-
-------
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-184-
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FIGURE 27
ESTIMATED CAPITAL COSTS FOR VARIOUS SIZE PLANTS
USING INCREASED EFFICIENCY LIMESTONE-LIME PROCESS (REF12)
ROTARY PRECOAT FILTRATION FOR SLUDGE DEWATERING
FOR MINE DRAINAGE CHARACTERISTICS SEE TEXT
60
5.5
5.0
4.5
4.0
o
-------
FIGURE 28
ESTIMATED CAPITAL COSTS FOR VARIOUS SIZE PLANT COMPONENTS
USING INCREASED EFFICIENCY LIMESTONE-LIME PROCESS(REF12)
ROTARY PRECOAT FILTRATION FOR SLUDGE DEWATERING
FOR MINE DRAINAGE CHARACTERISTICS SEE TEXT
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§ ROTARY PRECOAT FILTER
INSTALLATION AND PIPING
CONTINGENCIES AND ENGINEERING
" (4) THICKENER AND SLUDGE PUMPING
_ © SLUDGE DISPOSAL
© INSTRUMENTATION
(?) LIMESTONE STORAGE BIN, FEEDER a REACTOR
® LIME STORAGE BIN,FEEDER a REACTOR
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JD RAW FEED PUMP
0.5
1.5
2.0 2.5 3.0 3.5
CAPACITY MGD
-187-
4.0 4.5 5.0
-------
FIGURE 29
ESTIMATED OPERATING COSTS FOR VARIOUS SIZE PLANTS
USING INCREASED EFFICIENCY LIMESTONE-LIME PROCESS(REF 12)
ROTARY PRECOAT FILTRATION FOR SLUDGE DEWATERING
FOR MINE DRAINAGE CHARACTERISTICS SEE TEXT
1.2
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CHEMICALS
CAPITAL AMMORTIZED
3 4
PLANT SIZE-MGD
-188-
-------
Electrochemical Oxidation Followed by Limestone Neutralization
Tyco Laboratories, supported by the Environmental Protection Agency,
has developed an electrochemical oxidation process to oxidize ferrous iron be-
fore subjecting the mine drainage to limestone neutralization, Gaines, et. al,
1972'-*-'*' -*>. The logic being.that unlike most waste liquids, the high acid con-
tent of acid mine drainage produces a material of reasonable ionic conductivity.
In addition to accomplishing the desired oxidation, electrolytic hydrogen is pro-
duced as a by-product. At high AMD treatment rates, the recovery of this
hydrogen can produce a significant cost savings for the overall treatment process.
Basic Electrochemical Parameters - An acid mine water can contain on
the average 500 mg/1 of Fe^+ and 1, 000 mg/1 H+. Also present are variable
amounts of aluminum, calcium and manganese. As such, AMD is an electroly-
tically conducting solution and is capable of being treated electrochemically
without resort to additional additives. The pertinent electrochemical reaction
Fe2 +—- Fe3+ + e"
is carried out at an inert (nonconsumable) anode. Concurrently, on an inert
cathode, the reaction
H4" + e" -1/2 H2
will result in the removal of 1 mole of acid (and the generation of 1/2 mole of
hydrogen gas) for every mole of iron that is oxidized.
Carbon anodes, formed from a packed bed of activated carbon (4 x 10
mesh granules), were employed since carbon is inexpensive, readily available
in a variety of forms, resistant to chemical attack, and has a wide potential
range over which it is electrochemically stable (i.e. does not evolve QZ, 1^2 or
dissolve). As a cathode, 316 stainless steel perforated sheet was used since
this readily available material is highly resistant to corrosion in dilute sulfuric
acid solutions. The perforations in the cathode sheet allow the generated hydr-
gen bubbles to leave the reactor without obstructing electrode area.
Reactor Configuration - Treatment of 6, 000 gal. /hr. of AMD containing
500 mg/1 Fe^+ is considered as the base design of the packed bed reactor. The
ferrous concentration is to be reduced to five percent (5%) of its original value.
The proposed reactor configuration developed from experimental data
is outlined in Figure 30. The reactor is constructed in two series-connected
vertical tanks, each 8 feet high by 3 feet wide. Each tank is partitioned by
perforated stainless steel sheet into 35 flow channels, 1 inch wide, each treat-
ing 170 gal. /hr. of AMD. Each unit would thus be about 5 feet long for a total
reactor volume of 240 cu. ft.
-189-
-------
8 FT.
UNTREATED
1 AMD GENERATED
HYDROGEN
CATHODE
.PACKED BED ANODE
'" WIDE
-OXIDIZED AMD
(TO NEUTRALIZATION)
FIGURE 30
Oxidation Unit for Treating 6,000 gal./hr.
of 500 mg/1 Fe* + AMD
From: Gaines, et al. , 19?z(14)
-190-
-------
Devices capable of treating more than 6, 000 gal. /hr. of AMD would be
simple multiples of the proposed design. Thus the oxidation reactor for a large
AMD treatment plant operating at a peak process flow of 1, 000, 000 gal. /day
would occupy approximately 1,650 cu, ft.
Capital Costs - The capital cost analysis for a 6, 000 gal. /hr. , 95% con-
version, oxidation reactor are as follows:
Reactor
Stainless steel tank $10,000 Vendor Quote
Carbon bed @ 0.50/lb. 2,100
Other 1,400
13,500
Installation and start-up costs 6, 700
Total Cost $20,200
Net Capital Cost: 2.6^/1,000 gal. treated (25 yr. life, 4-1/2% interest
charge)
Due to the modular nature of electrochemical devices, the capital charge
of 2.6^/1,000 gal. is generally applicable to all situations where a conversion
of 95% is desired. The capital costs for conversion of 90% and 99%, i.e., for
initial Fe concentrations of 50 mg/1 and 1, 000 mg/1 treated to final ferrous
content of 5 mg/1 are:
Conversion, Capital Charge,
OOP gal.
90 1.9
95 2.6
99 3.8
Not included in the capital charges are the initial costs associated with
the AC -DC rectifying and control circuits required for the operation of the oxi-
dation reactor. These costs are sensitive to both AMD flow rate and initial
Fe concentration, as well as the desired conversion.
In addition to the capital charges described above, the only other cost
peculiar to the direct oxidation concept is the power cost associated with the
oxidation reaction. Labor and maintenance charges are not significant. The
electrochemical treatment step requires no operating labor and is easily con-
structed in a failsafe configuration.
The cost of the electrochemical oxidation step is compensated by cost
reductions in other parts of the treatment scheme. These cost reductions
accrue from the elimination of aeration equipment, the use of cheaper lime-
stone rather than lime to precipitate iron, and a reduction in equipment size
and disposal problems due to the denser more rapidly settling sludge produced
by the limestone treatment.
-191-
-------
The clarifier and/or settling pond requirements for limestone treat-
ment of ferric mine water, containing less than 5 mg/1 Fe^ + were estimated.
Primary settling, performed in a conventional clarifier-settler with a 1 hour
residence time, would discharge 10% of the total stream flow to a settling
pond/storage basin for final compaction and disposal. The use of a primary
clarifier, by reducing the sludge volume and increasing its solids content to
6 to 10% by weight, facilitates sludge disposal in shallow lagoons or abandoned
mine shafts. The costs associated with the final storage volume required are,
of course, dependent on the initial acidity and iron content of the AMD.
AMD Treatment Plant Design and Economics - Since AMD varies widely
in composition as well as flow rate, three flows and three ferrous iron concen-
trations were selected by Tyco Laboratories in order to represent a variety of
possible situations.
AMD Compositions and Flow Rates
Flow Rate, Fe2 + Concentration, Total Acidity
gal, /day ______ S3&/I __ _ mg/1
250,000 1,000 2,000
1,000,000 500 1,000
6,000,000 50 500
The basic treatment scheme proposed was the same in all cases. Under
the conservative assumption that no ferrous iron will precipitate during lime-
stone treatment, the oxidation reactor was designed for a final maximum Fe
concentration of 5 mg/1. Since the flow of mine drainage will vary to some ex-
tent, even on a daily basis, a holding pond with a controlled output was provided.
For plants with a low flow rate, the holding pond would also be used for AMD
storage, thereby reducing labor charges since continuous plant operation would
not be necessary.
Limestone slurry would be produced by loading a tumbling mill with bulk
limestone and providing a flow of water to give the slurry concentration desired.
Limestone containing 75% CaCC>3 costing $5 /ton F.O.B. was used as a basis for
estimating equipment size and operating costs.
The AMD from the holding pond is fed to the electrochemical oxidation
reactor. Following oxidation, the limestone slurry is added to the ferric mine
water in a simple neutralization reactor. In the absence of ferrous iron, the
precipitation is rapid and in a form favorable to rapid settling. A primary clari-
fier is used to separate the rapidly settling dilute sludge (about 10% of the total
stream flow) from the iron free supernate. The underflow from the primary
clarifier is sent to settling lagoons for final compaction and storage.
-192-
-------
The investment costs for the AMD treatment plants are listed in Table
15. Sizing of the process equipment was based on operating times of 8 hr. /day
for the 250, 000 gal. /day rate, 16 hr. /day at the 1, 000, 000 gal. /day rate, and
continuous operation at 6, 000, 000 gal. /day. Holding pond capacities were ad-
justed to provide a 30 hour retention volume. Process stream flows are thus
41, 600 gal. /hr. , 104, 000 gal. /hr. and 250, 000 gal. /hr. , respectively. The
capital costs associated with final sludge disposal are considered by Tyco Lab-
oratories to be too variable to be included without reference to a specific lo-
cation, this investment requirement is not included in the analysis.
The estimated operating expenses (exclusive of final sludge costs) are
shown in Table 16. For 500 mg/1 Fe2+, the operating costs range from 20£/
1, 000 gal. at 6, 000, 000 gal. /day to 55£/l, 000 gal. at 250, 000 gal. /day. Tyco
Laboratories found that comparable figures for current approaches to AMD
treatment were not readily available. In the one case where operating data was
available(16), a lime cost alone of 13^/1, 000 gal. was reported for a plant treat-
ing about 3, 000, 000 gal. /day of 200 mg/1 Fe2+, 700 mg/1 H+ AMD. They found
reported values for total treatment costs (including capital charges) range from
to $2/1,000 gal. treated.
The data in Tables 15 and 16 were updated to reflect prices in April,
1972 (from an ENR Construction Cost Index of 1575 to 1700). The updated
costs were plotted and the resulting cost curves are shown in Figures 31 and
32.
Credits for hydrogen production can only be estimated. Treatment of
1, 000 gal. of AMD containing 500 mg/1 Fe2 + will result in the generation of
15 cu. ft. of hydrogen. Optimized electrolytic hydrogen plants can produce
H2 at about 30^/100 cu. ft. Shipping charges will range from 20£ to $1/100
cu. ft. depending on distance and method. If the by-product hydrogen can be
sold at a credit (after collection and packaging costs) of 40^/100 cu. ft., the
credit to the treatment process would be 6£/l, 000 gal. of AMD treated. At
AMD flow rates of 6, 000, 000 gal. /day, this by-product return would repre-
sent a savings of 30% on total treatment costs. For streams containing 1,000
mg/1 Fe2"^, the savings approach 50% of total costs.
Although the cost of electrochemical oxidation of ferrous iron followed
by neutralization appears attractive, it must be understood that these are esti-
mates developed from bench scale experiments with no supporting data from
full scale operations.
-193-
-------
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TABLE 16
ESTIMATED OPERATING EXPENSES FOR
DIRECT ELECTROCHEMICAL OXIDATION TREATMENT PLANTS,
, 000 GAL.*
Flow Rate, Gal. /Day
Fe2+, mg/1
Acidity, mg/1
Treatment Power, 5 V
Plant Power
Limestone
Labor + Overhead
Depreciation
Total Costs
250, 000
50 500 1000
500 1000 2000
0.5 5.3 11
333
248
16 16 16
15 27 34
37 55 72
1, 000,000
50 500 1000
500 1000 2000
0.5 5.3 11
333
248
888
8.2 16 19
22 36 49
6,000,000
50 500 1000
500 1000 2000
0.5 5.3 11
333
248
222
367
11 20 31
Basis: Power at 1^/KWhr.
Depreciation at 10% of investment
Limestone at $6.67/ton (10% of basis)
Labor + overhead at $5/hr.
Plant On-Stream 8, 12 and 24 hours/day respectively
*Lime treatment range 20£ to $2/1,000 gal.
After Tyco Laboratories, Inc., 1972(15)
-195-
-------
FIGURE 31
ESTIMATED CAPITAL COSTS Vs. PLANT CAPACITY
FOR ELECTROCHEMICAL OXIDATION AND LIMESTONE NEUTRALIZATION TREATMENT
AFTER TYCO LABORATORIES, INC (REF 15 )
100
O.I
0.2
0.3 04 0.5
1.0 2.0
CAPACITY-MGD
4.0 5.0
10.0
-196-
-------
FIGURE 32
ESTIMATED ANNUAL OPERATING COSTS Vs. PLANT CAPACITY
FOR ELECTROCHEMICAL OXIDATION AND LIMESTONE NEUTRALIZATION TREATMENT
AFTER TYCO LABORATORIES,INC.(REF. 15 )
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-197-
-------
Biochemical Oxidation Followed by Limestone Neutralization
The existence of certain bacteria, commonly known as the acidophilic
iron bacteria, that specialize in the oxidation of ferrous to ferric iron at low
pH values has been known for years (^). In fact, these micro-organisms have
been isolated from many mine discharge waters.
Acidophilic iron bacteria are autotrophic (do not require organic sub-
stances for growth) and are classified as the Thiobacillus-Ferrobacillus group.
These bacteria utilize carbon dioxide as their source of carbon and oxidize
ferrous iron to the ferric state in order to obtain energy to drive their cell
machinery. In addition to carbon dioxide, oxygen and ferrous iron, these or-
ganisms also require lesser quantities of nitrogen and phosphorous and trace
amounts of other minerals ( •"•").
demonstrated that this microbial catalytic activity can be
economically utilized to satisfactorily prepare ferrous acid mine drainage
water for limestone treatment. His studies indicated that complete treatment
of an acid mine drainage could be achieved by preliminary biochemical oxi-
dation to convert ferrous salts to ferric, followed by neutralization with lime-
stone. A pilot plant was constructed in Great Britain to demonstrate the whole
process. A flow diagram of the plant is shown in Figure 33 and a dimensioned
sketch in Figure 34. The plant includes biochemical oxidation reactors, a new
upflow expanded bed limestone reactor, a sedimentation vessel, and a sludge
filter. The typical operating characteristics are summarized in Table 17.
Glover's patented process employs recirculation of active sludge con-
taining an active biological culture of acidophilic bacteria and in this respect
is similar to the activated sludge treatment of municipal sewage and certain
industrial wastes. On the pilot scale, it was possible to find sufficient de-
posited sludge in the mine drainage feed tank and in the limestone reactor
pump feed tank to start the biochemical reactors at a high rate. On the large
scale, it should be possible to start a plant by agitating the deposits in the
feed channels of the acid mine drainage and by driving the suspension forward
into the process where it would be retained' "'.
The neutralized drainage discharged from the limestone reactors was
foand to have relatively poor initial settling characteristics. Lime settling did
not occur and it was necessary to design sedimentation basins on a basis of
retention time for coagulation. Retention for four hours without any special
flocculating equipment or reagents produced a supernate having a suspended
solids content of less than 20 rng/1 which would be adequate to meet most re-
quired standards for discharges to inland watercourses in Great Britain. The
supernate contained most of the manganous salts which had been present in
the original mine drainage although some of the manganese had been absorbed
by the limestone neutralized sludge (Table 17).
-198-
-------
FIGURE 33
Flow Diagram of Complete Biochemical Oxidation
and Limestone Neutralization Process
Acid Mine
Drainage
Air
Limestone
Grit
Biochemical
Oxidation
,
—
Sedimentation
Treated
Effluent
Active
Sludge
After Glover, 1967(I9)
Cake To
Waste
-199-
-------
FIGURE 34
Acid Mine
Drainage
Air Supply
Main, 8gal./min., 5lb/in2
Air Lift,0.5tol.3gal./min.
Meterings
Pump Oxidizing Reactors
0 to l.3gal./min. 3x26.4 gal.
Active Sludge
•LT^ Recovery 39.6 gal.
Rest level of
Limestone
Float
Switch
-Attritor
-Sludge Rake
Purified
Effluent
Pump Feed Feed Pump
Tank approx.2IOgal. 5gal./min
f 6lbs./in.2
Two Limestone Grit
Reactors,IOft. high
6in I.D.
Dimensioned sketch of experimental pilot
scale biochemical oxidation and limestone
neutralization plant for acid mine drainage
treatment. The volume proportions of the
unit items of equipment are not necessarily
in the optimum ratio.
Volumes converted to U.S. gallons from
liters and imperial gallons.
After Glover, 1967 09)
Clarifier/Thickener
I2OO gal. approx.
Filter
Cake
Rotary Vacuum
Drum Filter
I ft.2Active Area
Not To Scale
-200-
-------
TABLE 17
TYPICAL OPERATING CHARACTERISTICS OF PILOT SCALE
BIOCHEMICAL OXIDATION AND LIMESTONE NEUTRALIZATION PROCESS
(COMPONENTS IN SOLUTION UNLESS OTHERWISE SPECIFIED)
Parameter
pH value
Ferrous mg/1 Fe
Ferric og/l Fe
Aluminium QgA Al
Manganese mg/1 Un
Calcium mg/1 Ca
Magnesium mg/1 Mg
Sodium mg/1 Na
Potassium mg/1 K
Sulphate mg/lSO,
Chloride mg/1 Cl
Silica mg/1 Si02
Carbon dioxide mg/1 C02
Combined Nitrogen mg/1 N
Arsenic mg/1 As
Total solids (dissolved)
mg/1
Suspended solids mg/1
Plow rate, max 0°C 1/min
Flow rate, max 10 C
1/min
Flow rate, max 20°C
1/min .
Influent
3.0
100-300
100-300
20-50
20
200
150
100
15
1500-2000
40
30
200
1-3
<0.02
2500
0-10,000
0.5
(cont)
2
(cont)
5
(cont)
After
oxida-
tion
and
Sedimen-
;ation
2.8
< 5
200-600
20
20
-
-
-
-
-
-
1
-
-
-
10
M
—
•.
After
Neutra-
lisation
5.8-6.5
< 5
0
0
16
-
-
-
-
-
-
-
-
-
-
-
1000
18
(int)
18
(int)
18
(int)
TJater
Phase
after
Second
Sedimen-
tation
6.0-6.5
< 1
0
0
11
-
-
-
-
-
-
-
-
-
-
-
<20
18
(int)
18
(int)
18
(int)
Sludge
Phase
after
Second
Sedimen-
tation
_
-
-
-
-
-
-
-
-
-
-
-
-
9-12J8
0.005
(cont)
0.02
(cont)
0.05
(cont)
Sludge
Phase
after
filtra-
tion
—
-
2(05 (dry
cake)
•••
-
-
-
-
-
-
-
-
-
-
-
-
45$
..
•w
_
After Glover,
-201-
-------
After consolidation for a few days, the sludge from the neutralization
process had a relative volume of about one percent (1%) of the volume of mine
drainage processed, and a solids content of 9 to 12 percent. This was a con-
siderable improvement compared to the sludge accumulation from lime treat-
ment of the same acid mine drainage which had a relative volume of about ten
percent (10%) and a solids content of about one percent (1%). The tenfold re-
duction in the volume of sludge produced is considered to be the main advantage
of the biochemical oxidation/limestone neutralization process.
The filtration rate of the sludge averaged 7 gal. /ft. /hr. From this
data it was calculated that vacuum filters of a total filtration area 250 ft.
operating 10 hr. /day, 7 days/week, would be sufficient to dewater the sludge
produced by biochemical oxidation/limestone neutralization 01 1, 000, 000 gal. /
day of acid mine drainage containing about 300 mg/1 of dissolved irom '».
The lower limit of acidity of an acid mine drainage which can be treated
by this process is determined by the pH value of the drainage after it has been
oxidized. The pH value of the drainage as discharged from the mining oper-
ation may be an insufficient guide since, for example, ferrous sulfate solutions
containing hundreds of mg/1 of iron are stable at almost neutral pH values.
The process should be applicable to mine drainages which contain at least 10
to 20 mg/1 of dissolved iron and a total acidity of 25 mg/1 (CaCO^) or more.
The upper limit of acidity which can be treated by the process would be
determined by the sulfate tolerance of the limestone process. It would prob-
ably be safe to assume that the upper limit will be 5, 000 mg/1 804, but it is
possible that higher limits may be acceptable due to the effect of the attritors( *9)
Higher limits would be possible if the reaction temperature was less than 15° C.
The extreme temperature limits for the complete process are expected
to be 0° C to 35° C, with a preferred working range of 5° C to 25° C. Tem-
peratures up to 30° C would increase the activity of the biochemical oxidation
stage, but temperatures down to 5° C would raise the sulfate tolerance of the
limestone stage.
The inability of the process to remove manganese salts from an acid
mine drainage is a distinct disadvantage which would be more acute at some
sites than others. In general, manganese salts are as much a pollutant as are
ferrous salts, although manganese salts do not produce such an obvious dis-
coloration of the stream bed.
The physical limitations of Glover's process are: 1) the mine drainage
must be at least slightly acidic, but not seriously contaminated with acidity,
2) the temperature must not be extreme, and 3) the manganous salt content
should not be excessive.
-202-
-------
A cost estimate was made by Glover'^' for treatment of an acid mine
drainage discharge from a shallow underground coal mine. The discharge
having a peak flow rate of 840, 000 gal. /day*, a maximum consecutive period
of 21 days at peak flow, and an average flow rate of 240, 000 gal. /day*. The
quality of the influent, effluent and cake from the biochemical limestone pro-
cess are as shown in Table 17. The quality of products from the lime process
are as near as possible similar.
**Estimated Costs $ I/Year Lime Process Biochemical/ Limes tone Process
Highest Probable
Capital $332,575 $154,760
Operating 53,000 31,005
Lowest Possible
Capital 52,470 31,138
Operating 58,035 33,920
*Converted from imperial to U. S. gallons
**Converted from British Pounds - One Pound Sterling = U.S. $2.65
It is evident the process, based on the above cost estimate, would have
a distinct cost advantage over the lime treatment process at the particular de-
gree of contamination represented by the sample mine drainage. It is expected
the cost advantage would increase as the mine drainage became less contamin-
ated since the lime process becomes progressively more difficult to operate
with the less contaminated mine waters. Conversely, the lime process in-
creases in efficiency as the degree of contamination rises. The break point
at which the lime process becomes cheaper than the biochemical limestone
process is not known, but it may be above the upper limit for the sulfate con-
tent of the biochemical limestone process, in which event it could conceivably
be cheaper to dilute the acid mine drainage to bring it within range of the bio-
chemical limestone process, although this would increase the load of dissolved
calcium salts discharged from the process.
As a generalization, it may be concluded that the biochemical limestone
process will find its application in the purification of the less contaminated acid
mine drainage, and that the conventional lime process will be more applicable
to the most highly contaminated acid mine drainages. The two processes are
thus to some extent complementary rather than competitive' ''.
Continental Oil Company* °' conducted studies to determine the abilities
of acidophilic bacteria to oxidize ferrous iron or to convert sulfate to hydrogen
sulfide and reached conclusions similar to that of Glover. They also found that
series multistaging of microbial oxidation vessels offers operational efficiency
over a single oxidation vessel. However, attempts of Continental to go from a
1-1/2 gallon bench size microbial oxidation system to a 1, 000 gallon pilot plant
oxidation vessel were not successful. As a result of their experiments, they
also found that although sulfate-reducing bacteria are present in acid mine drain-
age water, they will not grow or produce E^S at pH values below 5. 5.
-203-
-------
Lovelr ' conducted studies at the Pennsylvania State University Ex-
perimental Mine Drainage Research Facility, Hollywood, Pennsylvania, and
effectively treated waters containing up to 100 mg/1 iron II in a limestone
system without a separate iron oxidation step. Waters containing between
100 and 500 mg/1 iron II were successfully oxidized biochemically to levels
well below 100 mg/1 iron II and subsequently they responded satisfactorily to
the limestone reaction.
A bacterial strain, designated "Z, " was cultured from Hollywood waters
and utilized in these studies. It was presumed to be Ferrobacillus ferrooxidans.
Advantages in initiating the biochemical oxidation system were experienced
from inoculation with laboratory cultures, but continued introduction of inocu-
lant need not be maintained. Similarly, the addition of bacterial nutrients was
helpful to initiate growth but need not be continued. A bacterial culture at a
minimum level of 10" cells /ml appeared necessary and was maintained for the
study.
At Hollywood, Lowell\ employed an oxidation reactor in the form of
a trickling filter similar in design to a conventional sewage trickling filter
(Figure 35). It was filled with inert, minus four inch (-4") argillite to a depth
of five (5) feet. Hydraulic loading rates to this reactor were maintained at
levels up to 0. 16 GPM/square foot. There were no power or labor require-
ments for this operation which is an obvious advantage. A disadvantage to
using a stone -filled trickling filter is that it is liable to get plugged with sludge
build up; experimental work on plastic filter media with high void ratio is ex-
pected to solve this problem. A rotary tube mill is utilized as the limestone
reactor and the water retention time in the reactor was slightly over two min-
utes. Reactor power requirements ranged between 0.5 and 1.2 cents/ 1000
gallons with power priced at 1.7 cents /KWH. The rotary reactor was contin-
uously charged with limestone. The most satisfactory limestone appeared to
be a quarry waste which was relatively soft and degradable. Effluent from
the limestone reactor goes to an upflow clarifier. Frequently limestone sludges
with solids content as high as 15 percent by weight were obtained. Porous bot-
tom sludge drying beds dry this sludge to one -fourth of its original volume,
95 percent of the drying taking place in the first 48 hours. Similarly, the dry
solids rate of limestone sludges from precoat vacuum filtration ranged from
300-1, 200 Ibs. /ft. 2/24 hours. At 25 - 50 percent moisture in contrast to
30 - 40 Ibs. /ft. 2/24 hours obtained with lime-produced sludges. Detailed cost
estimates have not been developed for these facilities.
-204-
-------
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-205-
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Ozone Oxidation Followed by Limestone Neutralization
An engineering design and economic study to evaluate the feasibility
of ozone oxidation and limestone neutralization of acid mine drainage was
performed by Seller, Waide and Steinberg' ^' at Brookhaven National Lab-
oratory. The chemistry of using ozone for oxidation in low pH solutions is
expressed by the following equations:
(1) Oxidation
2 Fe+2 + 03 + 2 H + ^1 2 Fe+3 + H2O + O2
(2) Hydrolysis
Fe + 3 + 3
(3) Neutralization
3 H++ 3 OH" T~*" 3 H2O
Because acid mine waters range widely in flow rate and composition,
three flows and ferrous iron compositions were selected for the study which
generally encompass the conditions at typical acid mine drainage sites. The
acid mine drainage flow rates chosen are 250, 000, 1, 000, 000 and 6, 000, 000
gallons per day, containing ferrous iron contents of 50,300 and 1,000 parts
per million. The Fe+2 and total acidity used for the study are summarized
below. For simplicity, any acid resulting from the hydrolysis of metal ions
other than iron was ignored.
Fe+2 Cone, ppm p_H Total Acidjmg/l CaCOs)
1,000 2.5 1,900
300 2.5 650
50 2.5 200
Figure 36 shows the acid mine drainage oxidation neutralization pro-
cess system using ozone for oxidation of ferrous iron. The ozone is pro-
duced as a mixture containing 1.7 percent by weight of ozone (1% by volume)
in a gaseous oxygen stream. It is supplied to the oxidizing contactor, and
after reacting with the AMD, is recycled to ths ozone production unit. A
turbine type mixer is used in the oxidizing vessel as the contact device.
Ozone requirements for the various cases on which the study was based
are as follows:
-206-
-------
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-207-
-------
Ozone Requirements for AMD Streams
Ibs. /day Ozone
AMD Stream Flow-gal. /day
Fe Cone, -ppm 250.000 1,000,000 6,000,000
50 52 208 1,248
300 312 1,248 7,488
1,000 1,040 4,160 24,960
The ozone requirements are based on the sto.ichiom.etry of the oxida-
tion reaction:
2 Fe+2 + O3 + 2 H+—— 2 Fe+3 + H2O + O2
The following methods of ozone production were examined in the study
for their economic feasibility.
1. Electric discharge in oxygen.
2. Electric discharge in air.
3. Chemonuclear (Fission Fragment)
4. Isotopic sources (Gamma)
Tables 18 through 24 present the cost estimates worked out by Seller
et al.'"), which are plotted in the form of cost curves in Figures 37 through
40.
Beller et al. ', also worked out the investment cost necessary to
treat the entire acid mine drainage of southwestern Pennsylvania, estimated
at 486, 000, 000 gal. /day. The cost of $182, 000, 000 is based on the use of
a 200-ton per day central chemonuclear ozone plant. The investment cost in-
cludes ozone storage and shipment facilities and AMD treatment equipment
at each of the approximately 2, 160 sites in the region. Each site was assumed
capable of handling an average flow of 250, 000 gallons per day. A central
electric discharge plant would require an investment of about $191, 000, 000.
Table 25 gives this cost breakdown.
The cost estimates in this study were made about March, 1970 (U.S.
Average ENR Construction Cost Index 1314). They should be multiplied by
a factor of (1700/1314) = 1.3 to arrive at the ENR Construction Cost Index of
April, 1972.
The study consisted of an analysis of available methods of ozone pro-
duction and theoretical assumptions of acid mine drainage oxidation by ozone.
The conclusions reached in the study were not verified by actual laboratory
-208-
-------
or plant scale tests. Therefore, the cost estimates arrived at as a result of
the study, provide at the best, an indication of the probable costs should ozone
oxidation materialize as a proven and tested method for acid mine drainage
treatment.
-209-
-------
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-210-
-------
TABLE 19
AMD TREATMENT PLANT OPERATING COSTS* - C/IOOO GAL.
AMD F3.0W 666
Gal./Day 0.25 X 10 1 X 10 6 X 10
Fe++, ppm. J50 300 1000 J50 300 1000 J30_ 300 1000
Depreciation
f> 1.3% 5.1 5.2 5.2 3.8 4.0 4.3 3.2 3.4 3.6
Power @
8 mil.Kw-Hr 3.2 3.3 3.5 3.2 3.3 3.5 3.2 3.3 3.5
Limestone
@ $5/Ton 0.5 1.6 4.4 0.5 1.6 4.4 0.5 1.6 4.4
TOTAL 8.8 10.1 13.1 7.5 8.9 12.2 6.9 8.3 11.5
*Not including ozone.
After Beller et al, (23)
-211-
-------
TABLE 20
AMD TREATMENT TOTAL OPERATING COST
fr/1000 Gal.
AMD FLOW, GPD
Fe , ppm
0.25 X 10
1.0 X 10
6.0 X 10
50 300 1000 50 300 1000 50 300 1000
OZONE GENERATED ON SITE-ELECTRIC DISCHARGE OZONIZERS
A. ONCE-THROUGH AIR FEED. 7.25 KW-Hr/lb
OZONE
AMD PLANT
TOTAL
OZONE
AMD PLANT
TOTAL
OZONE
AMD PLANT
TOTAL
OZONE
AMD PLANT
TOTAL
3.6 20.1
8.8 10.1
12.4 30.2
61.1
13.1
3.4 18.1
7.5 8.9
55.0
12.2
2.8 16.0
6.9 8.3
74.3 10.9 27.0 67.2 9.7 24.3
B. ONCE-THROUGH AIR FEED, 9.75 KW-Hr/lb
4.2 24.8
8.8 10.1
13.0 34.9
75.3
13.1
4.2 22.2
7.5 8.9
88.4 11.7 31.1
67.9
12 ; 2
80.1 10.6 27.9
3.7 19.6
6.9 8.3
C. OXYGEN FEED WITH RECYCLE, 3.75 KW-Hr/lb
4.9 21.2
8.8 10.1
13.7 31.3
56.5
13.1
3.7 16.5
7.5 8.9
69.6 11.2 25.4
45.7 2.7 12.6
12.2 6.9 8.3
57.9 9.6 20.9
D. OXYGEN FEED WITH RECYCLE. 5.0 KW-Hr/lb
5.5 24.1
8.8 10.1
14.3 34.2
65.2
13.1
4.3 19.1
7.5 8.9
52.9
12.2
3.2 14.5
6.9 8.3
78.3 11.8 28.0 65.1 10.1 22.8
51.7
11.5
63.2
62.5
11 ._5
74.0
35.8
11.5
47.3
42.1
11.5
53.6
After Beller, et al, (23)
-212-
-------
TABLE 21
OZONE GENERATED IN 40 TON/DAY CENTRAL PLANT, SHIPPED TO AMD SITE
e/1000 Gal.
AMD FLOW, GPD
++. ppm
Fe
0.25 X
50 300
A. ELECTRIC DISCHARGE
1. 5
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2. 6
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
io6
1.
1000 50
OZONIZERS,
MIL./KW-Hr POWER
1.2 7.0
8.8 10.1
0.9 5.4
2.0 2.0
12.9 24.5
23.
13.
14.
2.
52.
MIL./KW-Hr POWER
1.5 8.0
8.8 10.1
0.9 5.4
2.0 2.0
13.2 25.5
B. CHEMONUCLEAR OZONE
1. G
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2. G
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
= 15, E = 0.
1.0 5.8
8.8 10.1
0.9 5.4
2.0 2.0
12.7 23.3
= 10, E = 0.
1.3 6.8
8.8 10.1
0.9 5.4
2.0 2.0
13.0 24.3
26.
13.
14.
2.
55.
COST
3 1.
1 7.
0 0.
0 1.
4 10.
COST
0 1.
1 7.
0 0.
0 1.
1 10.
2
5
9
0
6
5
5
9
0
9
, RECYCLED 0
20
19.
13.
14.
2.
48.
20
22.
13.
14.
2.
51.
5 1.
1 7.
0 0.
0 1.
6 10.
5 1.
1 7.
0 0.
0 1.
6 10.
0
5
9
0
4
3
5
9
0
7
0 X
300
io6
1000
RECYCLED
7.0
8.9
5.4
1.0
22.3
8.0
8.9
5.4
1.0
23.3
5.8
8.9
5.4
1.0
21.1
6.8
8.9
5.4
1.0
22.1
23.
12.
14.
1.
50.
26.
12.
14.
1.
53.
19.
12.
14.
1.
46.
22.
12.
14.
1.
49.
0.,
3
2
0
0
5
0
2
0
0
2
5
2
0
0
7
5
2
0
0
7
1
6
0
0
9
1
6
0
0
9
1
6
0
0
9
1
6
0
0
9
6
50
5
.2
.9
.9
.5
.5
.5
.9
.9
.5
.8
.0
.9
.9
.5
.3
.3
.9
.9
.5
.6
.0 X
300
io6
1000
KW-Hr/lb
7.0
8.3
5.4
0.5
21.2
8.0
8.3
5.4
0.5
22.2
5.8
8.3
5.4
0.5
20.0
6.8
8.3
5.4
0.5
21.0
23.3
11.5
14.0
0.5
49.3
26.0
11.5
14.0
0.5
52.0
19.5
11.5
14.0
0.5
45.5
22.5
11.5
14.0
0.5
48.5
After Beller et al, (23)
-213-
-------
TABLE 22
OZONE GENERATED IN 200 TON/DAY CENTRAL PLANT. SHIPPED TO AMD SITE
C/1000 Gal.
AMD FLOW, GPD
Pe , ppm
0.25 X
50 300
A. ELECTRIC DISCHARGE
1.
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2.
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
106
1000
1.
50
OZONIZERS,
5 MIL./KW-HR POWER
1.1 6.4
8.8 10.1
0.9 5.4
2.0 2.0
12.8 23.9
21.
13.
14.
2.
50.
6 MIL./KW-HR POWER
1.2 7.2
8.8 10.1
0.9 5.4
2.0 2.0
12.9 24.7
B. CHEMONUCLEAR OZONE
1.
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2.
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
G = 15, E = 0
0.7 4.1
8.8 10.1
0.9 5.4
2.0 2.0
12.4 21.6
G = 10, E = 0
0.9 5.2
8.8 10.1
0.9 5.4
2.0 2.0
12.6 22.7
24.
13.
14.
2.
53.
0 X 10
300
6
1000
RECYCLED
0^,
6.
50
, 5
0 X 10
300
6
1000
KW-Hr/lb
COST
3
1
0
0
4
1.1
7.5
0.9
1.0
10.5
6.4
8.9
5.4
1.0
21. .7
21
12
14
1
48
.3
.2
.0
.0
.5
1.
6.
0.
0.
9.
1
9
9
5
4
6.4
8.3
5.4
0.5
20.6
21.3
11.5
14.0
0.5
47.3
COST
0
1
0
0
1
1.2
7.5
0.9
1.0
10.6
7.2
8.9
5.4
1.0
22.5
24
12
14
1
51
.0
.2
.0
.0
.2
1.
6.
0.
0.
9.
2
9
9
5
5
7.2
8.3
5.4
0.5
21.4
24.0
11.5
14.0
0.5
50.0
, RECYCLED 0.
.20
13.
13.
14.
2.
42.
.20
17.
13.
14.
2.
46.
7
1
0
0
8
3
1
0
0
4
0.7
7.5
0.9
1.0
10.1
0.9
7.5
0.9
1.0
10.3
i
4.1
8.9
5.4
1.0
19.4
5.2
8.9
5.4
1.0
20.5
13
12
14
1
40
17
12
14
1
44
.7
.2
.0
.0
.9
.3
.2
.0
.0
.5
0.
6.
0.
0.
9.
0.
6.
0.
0.
9.
7
9
9
5
0
9
9
9
5
2
4.1
8.3
5.4
0.5
18.3
5.2
8.3
5.4
0.5
19.4
13.7
11.5
14.0
0.5
39.7
17.3
11.5
14.0
0.5
43.3
After Beller et al, (23)
-214-
-------
TABLE 23
TOTAL INVESTMENT COSTS FOR AMD TREATMENT
USING ON-SITE OZONE WITH RECYCLED OXYGEN FEED
5.0 KWH/LB OZONE
COSTS IN THOUSANDS OF DOLLARS
AMD FLOW,
GAL. /DAY
Fe+2 CONC'N
ppm
OZONE PLANT
AMD PLANT
TOTAL $
250,
50
14
52
66
000
300
60
53
113
1
1000 50
190 40
53 156
243 196
,000,
300
220
163
383
000
1000
530
175
705
IP.
220
790
1010
6,000,
300
810
830
1640
000
1000
2130
855
2985
After Seller et al, (23)
-215-
-------
TABLE 24
COMPARISON OF AMD TOTAL TREATMENT COSTS
COSTS IN CENTS PER 3000 GAL.
AMD FLOW - GAL. PER PAY
0.25 X 106 1.0 X 106 6.0 X 1Q6
Fe''"1' CONTENT-ppm .50 300 1000 £0 300 1000 j>0 300 1000
1. ELECTRIC DISCHARGE WITH RECYCLED OXYGEN FEED, ON-SITE OZONE GENERATION
@> 3.75 Kwh/lb. 14 31 70 11 25 58 10 21 47
@ 5.00 Kwh/lb. 14 34 78 12 28 65 10 23 54
2. ELECTRIC DISCHARGE WITH ONCE-THROUGH AIR FEED. ON SITE OZONE GENERATION
g> 7.25 Kwh/lb. 12 30 74 11 27 67 10 24 63
@ 9.25 Kwh/lb. 13 35 88 12 31 80 11 28 74
CENTRAL OZONE PLANTS WITH DISTRIBUTION SYSTEMS
3. ELECTRIC DISCHARGE. 40 TON/DAY OZONE
@ 5 mil/Kwh power 13 24 52 11 22 50 10 21 49
g> 6 mil " " 13 26 55 11 23 53 10 22 52
4. ELECTRIC DISCHARGE, 200 TON/DftY OZONE
@ 5 mil/Kwh power 13 24 50 10 22 48 9 21 47
@ 6 mil/ " " 13 25 53 11 23 51 9 21 50
5. CHEMONUCLEAR, 40 TON/DAY OZONE
G=10. E=0.20 13 24 52 11 22 50 10 21 48
G=15. E=0.20 13 23 49 10 21 47 9 20 45
6. CHEHONUCLEAR, 200 TON/DAY OZONE
6=10. E=0.20 13 23 46 10 21 44 9 19 43
6=15, E=0.20 12 22 43 10 19 41 9 18 40
After Beller et al, (23)
-216-
-------
FIGURE 37
80
70
60
50
40
*
< 30
o
8 20
I '0
fe °
O
O
H
5 90
2
£ 80
60
50
40
30
20
10
0
ON-SITE OZONE GENERATION
RECYCLED OXYGEN FEED
0.25 x I06GPD
1.0 xlO GPD J
6.0 x!06GPD J
3.75 KW-HR/LB
5.0 KW-HR/LB
ON-SITE OZONE GENERATION
ONCE-THROUGH AIR FEED
xlO GPD
HR/LB
HR/LB
I
I
200 400 600 800 1000
Fe*+ CONTENT-ppm
TOTAL AMD TREATMENT COSTS USING OZONE
ELECTRIC DISCHARGE OZONIZERS
After Seller et al, (23)
-217-
-------
FIGURE 38
UJ
h;
S
on
i
<
60
50
40
< 30
o
8 20
o
^ 10
i
h-
co
o
o
60
50
40
30
20
10
0.25-j 6
1.0 UlOGPD
6.0 J
___
°'Z5\
1.0
J
1.0 lO GPD.
6.0
OZONE CAPACITY-40TON/DAY
6MIL/KW-HR POWER
5MIL/KW-HR POWER
xlO GPD
OZONE CAPACITY-200 TON/DAY
-6MIL/KW-HR POWER
-5MIL/KW-HR POWER
1
j_
0 200 400 600 800 1000
Fe++CONTENT-ppm
TOTAL AMD TREATMENT COST USING ELECTRIC-DISCHARGE OZONE
CENTRAL PLANT OZONE GENERATION.SHIPPED TO AMD SITE
5KW-HR/LB 0, POWER CONSUMPTION
After Beller et al, (23)
-218-
-------
FIGURE 39
O
O
o
-------
FIGURE 40
3000
2800
200
RECYCLED OXYGEN FEED
5.0 KWH/LB OZONE
6x I0 GAL/DAY AMD
I x I06 GAL/DAY AMD
0.25 x I06 GAL/DAY AMD
200 400 600 800
Fe++ CONTENT - ppm
1000
TOTAL PLANT INVESTMENT COST FOR AMD TREATMENT
USING ON-SITE ELECTRIC DISCHARGE OZONE
After Seller et al, (23)
-220-
-------
TABLE 25
COST, BREAKDOWN FOR TOTAL AMD TREATMENT
OF PENNSYLVANIA AMD STREAMS
486 MILLION GALLONS PER DAY
Investment Costs - Million Dollars
Central Central On-Site
Chemo- Elec. Elec.
nuclear Disch. Disch.
Ozone Plants
AMD Neutrali-
zation*
Total Investment
26.0
156.0
182.0
Operating
Central
Chemo-
nuclear
Depreciation-7.3% 9.1
Nucl. Fuel Cycle 0.9
Labor 2 . 1
Power
Maintenance
Purchased Oxygen
Distribution
Limestone
Total Operating
Costs
3.9
0.1
0.8
1.2
18.1
34.8
156.0
190.8
Costs -
99.5
113.0
212.5
C/1000 Gal.
Central On-Site
Elec. Elec.
Disch
9.6
2.1
6.3
0.1
0.8
1.2
20.1
Disch.
10.6
1.0
7.2
1.0
5.4
1.2
26.4
Annual Operating
Costs $26.4x10 $29.3x10 $38.5x10
*
Assumes 2,160 AMD treatment sites with average flow
rates of 250,000 gpd.
After Beller et al, (23)
-221-
-------
Neutralization of Mine Drainage with High Ferric Iron Content
Neutralization of mine drainage with high ferric iron content can be
accomplished more easily and at less cost compared to treatment of mine
drainage high in ferrous iron. Equipment, chemicals and methods necessary
for oxidation of ferrous iron can be eliminated with consequent reduction in
cost and simplification of treatment.
Wilmoth and Hill' ' conducted continuous flow and batch test studies
utilizing lime, limestone and soda ash to treat acid mine drainage having a
high ferric/ferrous ratio. Some of their conclusions and recommendations
were:
1. Chemical costs for treating by the three methods were: soda ash - 0.049
cents, limestone - 0.010 cents, and lime - 0.005 cents per mg/1 acidity
per 1,000 gallons. These costs updated to April, 1972, using the ENR
Construction Cost Index, would be respectively: 0.075 cents, 0.015 cents
and 0.0075 cents per mg/1 acidity per 1, 000 gallons.
2. Lime is a very reactive material and the neutralization reaction goes to
completion in less than half an hour. The limestone reaction requires 24
to 48 hours to go to completion and therefore, requires a long detention
time before discharge, however, aeration will reduce the detention time
to one comparable to lime.
3. The limestone reaction is not very sensitive quantitatively, i.e., small
changes in limestone feed rate or water quality do not cause large changes
in product water quality so the accuracy with which constituents are fed
into the reactor need not be controlled with the precision required by lime.
Accidental overtreatment is not the pollution problem with limestone that
it would be with lime.
4. Lime is capable of attaining high pH's which may be necessary in so.tne
cases for desired water quality, whereas with limestone, pH's above 7.0
are very difficult to attain.
5. All three neutralizing agents were capable of treating the high ferric acid
mine drainage. Lime costs were half that of limestone for treating the
same acid mine drainage because of the low utilization of limestone. How-
ever, the characteristics of the limestone sludge were superior; it occupied
approximately two-thirds of the volume of lime sludge and had a higher
solids content. The limestone sludge also had a large residual alkalinity
which would be beneficial when disposed into an acid environment (although
this residual alkalinity is expensive and of questionable value to the treat-
ment process).
-222-
-------
6. Studies should be made to develop methods of increasing the efficiency
of limestone as a neutralization agent in acid mine drainage treatment
because of the lower initial cost and low sludge volume. Studies should
be made on:
a) Sludge return to take advantage of the residual alkalinity within the
sludge.
b) Increasing the detention time in the reactor to allow more limestone
to go into solution.
c) Increasing the shearing action in the reactor to break the calcium
sulfate and iron coating of the limestone.
d) Combination lime stone-lime to utilize the strong points of each, i. e,
limestone for low pH's to around pH 5 (the most efficient portion of
the limestone curve) and then the use of lime to further increase the
pH.
e) Developing methods to produce a rapid settling and dense sludge,
e.g., the use of coagulating aids.
Calhoun^ ' in discussing the design and operation of a limestone treat-
ment plant for the Rochester & Pittsburgh Coal Company, Indiana, Pennsyl-
vania, expressed the opinion that the limestone treatment method should always
be investigated prior to installation of a permanent treatment plant because
some types of mine drainage can be treated with a limestone system. The
reasons given are: 1) most economical, 2) a lesser volume of sludge for dis-
posal, and 3) there is no danger of overtreatment. He also said, it appears
a combination limestone-lime treatment method would be most economical
for treatment of a difficult water with a high ferrous iron content. These
statements are in agreement with the studies of Wilmoth and Hill.
At the Rochester & Pittsburgh Coal Company treatment site the mine
drainage has the following average characteristics: pH - 3. 1, acidity - 350
mg/1, iron - 56 mg/1 (less than 10% in the ferrous state), dissolved solids -
1,600 mg/1, and a volume of 150/gpm.
The treatment facility consists essentially of a rotating drum as a re-
actor to tumble the limestone and a settling pond. The average quality of the
effluent from the settling pond in 1967 was: pH - 6.9, alkalinity - 18 mg/1,
and iron -1.4 mg/1.
It is estimated capital costs for new equipment for the treatment plant
would be close to $20, 000. Actual costs were somewhat lower because second
hand equipment was utilized. Operating costs, including limestone, power,
maintenance and labor was estimated to be about 6^/1,000 gal. treated (esca-
lated to 1972 price levels it would be about 10^/1,000 gal. treated).
-223-
-------
Mine Drainage Treatment Using Hydrated Lime
In 1970, Heine and Giovannitti^ ' said, "The science and technology
of mine drainage treatment is in its infancy in the United States with the most
significant recent advancements occurring in Pennsylvania." This is still the
case two years later. Mine drainage technology is undergoing a period of rapid
growth. The pace of research and development is so rapid, that some treat-
ment plants can be said to be obsolete before they go into operation.
There are now probably close to three hundred plants treating mine
drainage. Most of these plants are in Pennsylvania and many of them have
been in operation for less than three years. The majority of the treatment
plants use lime as the neutralizing agent. In the next few years, this dom-
ination by lime neutralization could conceivably change as the results of re-
cent limestone and lime stone-lime treatment technology are put into effect.
In estimating costs for mine drainage treatment, it should be recog-
nized that much of the actual cost data developed to date is based on lime
neutralization. Because of the newness of mine drainage treatment technology
the capital and operating costs of existing treatment plants may not be an indi-
cation of future costs in mine drainage treatment. It is obvious when one re-
views recent research and development that if the information was available
at the time many of the existing plants were planned, the design and operation
would be considerably different. Although most of the lime neutralization
plants in operation today are effectively treating acid mine drainage at costs
that are relatively economical, they are at best primitive examples of mine
drainage treatment in the dawn of a developing technology. Further econo-
mies can accrue from more efficient operation and design as a result of the
progress being made in mine drainage treatment technology.
Hydrated Lime Process - Basically this process involves four steps
in treating acid mine drainage.
1. Neutralization which entails the conversion of
a) Sulfuric acid to calcium sulfate
Ca(OH)2 + H2SO4 *-CaSO4 + 2 H2O
b) Ferrous sulfate to ferrous hydroxide and calcium sulfate
Ca(OH)2 + FeSO4 *-Fe(OH)2 + CaSO4
2. Aeration - The oxidation of ferrous hydroxide to ferric hydroxide
O2 + 4 Fe(OH)2 + H20 *-4 Fe(OH)3
3. Clarification - Thickening
-224-
-------
4. Sludge Dewatering and Disposal
The advantages of lime treatment are: 1) removal of acidity, 2) re-
moval of iron and aluminum salts, 3) reduction in sulfate ion concentration,
4) relative simplicity and control, and 5) ready availability of lime.
The disadvantages are: 1) addition of hardness to effluent, 2) gypsum
scale on plant equipment and possibly in effluent, 3) difficulty in sludge hand-
ling and dewatering, 4) volume of sludge production and disposal, and 5)
possibility of overtreatment with detrimental effects.
Engineering Cost Factors - The following engineering cost factors
should be considered in estimating costs of lime treatment facilities.
1. Treatment Plant Capacity - The capital cost of a plant is determined by
its construction cost which to some extent is affected by the acidity and
iron content of mine drainage to be treated. The operating costs are more
affected by the acidity and iron content than by the plant size.
2. Lime Storage Facilities - These facilities depend for their sizing on acid-
ity characteristics as well as the volume of mine drainage to be treated.
3. Mixing and Aeration - The purpose of mixing is two fold: 1) it must dis-
perse the solid hydrated lime in mine water and 2) it must produce tur-
bulence of high intensity around the hydrated lime particles in order to
promote a mass transfer between the two phases. Dorr-Oliver, Inc.
reports(27» 28) tnat with a separate flash mixing operation, a detention
time of one minute was found sufficient to ensure neutralization.
4. Aeration - "Operation Yellowboy" data^"' indicates a detention time of
about 30 minutes with efficient aeration equipment is sufficient.
5. Settling and/or Thickening - Sludges formed in lime treatment are typi-
cally slow in settling from solution. In this respect, lime treatment is
at a disadvantage in comparison with limestone treatment, which pro-
duces a more rapidly settling sludge of less volume. "Operation Yellow-
boy"^ ') used a thickener to separate the iron oxide-gypsum sludge
mixture, and subsequent centrifugation as a sludge dewatering process.
Also, according to "Operation Yellowboy" data, settling and thickening
may represent a significant cost in capital plant expenditures.
The sludge volume typically produced in lime treatment represents a
high percentage of the influent volume and the solids content ranges
from 1 to 10%. The solids contentdoes increase with time. Polymeric
flocculants improve the settling characteristics of sludge, but they do
not increase the solids concentration.
-225-
-------
Kostenbader and Haines^ ' ' report the development of a high-density
sludge (HDS) process which, in addition to the usual lime treatment pro-
cess, involves recycling a controlled volume of the settled sludge and
mixing the recycled sludge with lime slurry in a reaction tank prior to
the neutralization and separation steps. Figure 41 shows the flow dia-
gram of the HDS process. Depending mainly on the oxidation state of
iron in the mine water, the sludges produced can contain 15 to 40% solids.
The HDS process is claimed to be inherently well-suited for treating acid
mine drainage with high ferrous/ferric iron ratios.
If land space is available, lagoons could be used for sludge settling as an
alternative to mechanical thickening. Two or more lagoons or basins
could be used, and after sludge settling, the supernatant may be removed
by pumping, or the sludge may be allowed to dry in the lagoon.
6. Sludge Dewatering - The "Operation Yellowboy" projects employed various
dewatering techniques, including centrifugation and filtration. A drum
filter process increased solids concentrations from initial ranges of 0.9
to 5 percent to final solids concentrations of 21 to 27 percent.
Rotary precoat filtration, centrifugation, pressure filtration, freezing,
cycloning, CC>2 pretreatment, and other methods of sludge densification
and dewatering have also been studied^ > ^ '.
7. Sludge Disposal - The disposal of sludge is a major problem in mine drain-
age treatment. Holland et al. (^), estimated costs of disposing of sludge in
lagoons. These estimates show costs may amount to 13 to 15 percent of
the total annual plant operating costs for treating highly acid mine drainage,
11 to 13 percent for moderately acid discharges and 7.5 to 10 percent for
weakly acid discharges. Holland points out that the cost could be higher
because the cost of sludge disposal in lagoons is markedly affected by land
availability, soil type, underlying rock, ground water, etc. He also sug-
gests the possibility of using nearby abandoned mines for sludge disposal.
Where possible, sludge should be pumped to abandoned mines. Deep in-
jection wells cannot be used where the subsurface geology is unfavorable
and it is questionable whether this method is practical for acid mine drain-
age sludge disposal. Evaporation ponds are not functional in areas where
annual rainfall exceeds annual evaporation. Rinne(^ ' provides costs for
evaporation ponds and for deep well disposal of brine (Tables 26 and 27).
Steinman^35' reports that at the Thompson Mine Drainage Treatment Plant
of Jones and Laughlin's Vesta Shannopin Coal Division, it was found more
economical to truck the sludge rather than acquire land and construct a
large sludge lagoon. Dean(3°) describes methods of sludge disposal in
detail. Osman et al. (^'), investigated mine drainage sludge utilization.
Their research covered: 1) additives used in the building materials in-
dustry, 2) recovery of iron, 3) the application of gypsum technology to
the sulfate portion of the sludge, and 4) separation of the major chemical
components. They found that manufacture of synthetic light-weight aggre-
-226-
-------
UJ
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TABLE 26
COST OF BRINE DISPOSAL IN EVAPORATION PONDS
(Assuming PVC Liner at $0. 30 per sq. ft. )
1. 0 MGD Brine
Arkansas Gallup, Midland,
City, Ark. N.M. Texas
Net Avg. Annual Pond Evapo- 14 30 40
ration (inch)
Pond Area (acres) 960 468 343
Pond Construction Cost 15.27 7.34 5.38
($ x 106)
Total Annual Operation Cost 1.73 0.84 0.62
($/yr. x 106)
Cost per 1, 000 gals, of brine $5.20 2.50 1.92
90% recovery of feed 0.52 0.25 0.19
($/l, 000 gallons)
fresh water
TABLE 27
ESTIMATED COSTS OF DEEP WELL DISPOSAL
Arkansas City Midland Ft. Morgan
Prod. Vol. (MGD) 7.0 5.0 3.0
Brine Vol. (MGD) 1.27 0.8 1.0
Well Construe. Cost($xl06) 0.195 0.157 0.787
Total Cap. Cost ($ x 106) 0.258 0.401 1.775
Total Annual Cost ($/yr. x 106) 0.063 0.120 0.384
Product Water Bases
Total Unit Cap. Cost 0.369 0.080 0.591
($/gal./day)
Total Unit Oper. Cost 0.025 0.066 0.35
($/l, 000 gallons)
After Rinne, 1970(34)
Costs not updated to 1972.
-228-
-------
gates and structural bricks utilizing small percentages of sludge was
technically feasible and recovery of iron was also generally successful.
The high-iron content sludge (alkaline) can be pallatized and used directly
as a blast furnace feed after dewatering. The high-sulfate sludge (acid),
when pre-reduced at high temperature to decompose the calcium sulfate,
can be agglomerated into a blast furnace feed. Additional research is
needed before these results can be considered commercially attractive.
"Operation Yellowboy" projects^27'28> 29» 38'39), Holland, et al. (3) and
Selmeczi' 0' provide useful design information for lime neutralization
treatment plants.
Tables 28, 29 and 30 give the actual costs of five "Operation Yellowboy"
projects. Tables 31, 32 and 33 give the estimated costs using hydrated
lime as taken from the work of Holland, et al.'-5). These costs were up-
dated to April, 1972 price levels using the ENR Construction Cost Index
and plotted as cost curves in Figures 42, 43 and 44.
-229-
-------
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TABLE 31
Estimated Costs of Neutralizing Highly Acid Mine Water Using Hydrated Lime
(All Costs in Cents per 1000 Gallons of Water Treated)
Plant
Capacity
Gallons /Day
300,000
900, 000
2,700,000
8, 100,000
Labor
10
5
2.5
2
Lime
28
26
25.5
25.5
Plant Cost
Except
Sludge
Disposal
9.5
8.5
7.25
7.25
Sludge
Disposal
Cost
8
7
7.75*
7.50*
Repair
4
3
2.5
2.5
Misc.
3
3
3
3
Total
62.5
52.5
48.5
47.75
Accumulation of
Sludge in
One-Year
Acre-Feet
9.8
30. 1
91.0
273.0
Acidity 2800 - 4000
Iron 900 - 1200
Bag Lime $24,00/Ton
Bulk Lime $22.00/Ton
TABLE 32
Estimated Costs of Neutralizing Moderately Acid Mine Water Using Hydrated Lime
(All Costs in Cents per 1000 Gallons of Water Treated)
Plant
Capacity
Gallons /Day
300,000
900,000
2,700,000
8, 100,000
Labor
8
4
2
1.6
Lime
12.9
11.5
11
11
Plant Cost
Except
Sludge
Disposal
9.5
8.5
7.75
7.25
Sludge
Disposal
Cost
4
3.5 *
3.75*
3.75*
Repair
3
2.5
2
2
Misc.
3
3
3
3
Total
34.8
33.0
29.5
28.6
Accumulation of
Sludge in
One-Year
Acre-Feet
4.9
15.4
45.5
136.5
Acidity around 1400 PPM
Iron around 600 - 700 PPM
Bag Lime $24.00/Ton
Bulk Lime $22.00/Ton
TABLE 33
Estimated Costs of Neutralizing Weak Acid Mine Water Using Hydrated Lime
(All Coats in Cents per 1000 Gallons of Water Treated)
Plant
Capacity
Gallons /Day
300, 000
900,000
2,700,000
8, 100, 000
Labor
6
3
1.8
1
Lime
6.1
5.7
5.5
5.5
Plant Cost
Except
Sludge
Disposal
8.5
7.5
6.75
6.5
Sludge
Disposal
Cost
2
1.8
1.9*
1.9*
Repair
2.5
2
1.5
1.5
Misc.
2.5
2.5
2.5
2.5
Total
27.60
22.50
19.95
18.90
Accumulation of
Sludge in
One-Year
Acre-Feet
2.8
7.7
23.1
68.6
Acidity around 600 - 700,
Iron 322,
Bag Lime $24. 00/Ton
Bulk Lime $22. 00/Ton
After Holland, et al <3'
*These costs allow for excavating some hard rock.
-233-
-------
FIGURE 42
CAPITAL COST Vs. PLANT CAPACITY
HYDRATED LIME TREATMENT PLANT WITH SLUDGE DISPOSAL
REFERENCES^ 29 a 41
01
IOO
-234-
-------
FIGURE 43
TOTAL CAPITAL COST Vs. PLANT CAPACITY
HYDRATED LIME TREATMENT PLANT
(WITHOUT SLUDGE DISPOSAL) REF 3
O.I
0.2 0.3 0.4 0.5
1.0 2
CAPACITY-MGD
345
10
-235-
-------
FIGURE 44
TOTAL OPERATING COST (Including Capital Costs)
HYDRATED LIME TREATMENT (REF 3 )
100-r
3O-
_J
CP
o
Z 2.0-
_L
LIRON-PPM
ACIDITY-PPM
•HIGHLY ACIDIC
MODERATELY ACIDIC
WEAKLY ACIDIC
50
4O - ---
900-1200
600-700
322
2800-4800
1400
600-700
/— HIGHLY ACIDIC (WITH SLUDGE DISPOSAL)
2— HIGHLY ACIDIC (WITHOUT SLUDGE DISPOSAL)
J- MODERATELY ACIDIC (WITH SLUDGE DISPOSAL) j
4 -MODERATELY ACIDIC (WITHOUT SLUDGE DISPOSAL)
5 —WEAKLY ACIDIC (WITH SLUDGE DISPOSAL)
6 - WEAKLY ACIDIC (WITHOUT SLUDGE DISPOSAL)
1.0
CAPACITY-MGD
100
-236-
-------
Cost of Lime Neutralization of Mine Drainage - Mine drainage is a
complex waste which varies in quality, quantity and inherent characteristics
from mine to mine and even within the same mine from place to place and
with time. The cost of treating mine drainage, therefore, will vary with
the quantity of drainage requiring treatment, the initial quality and the de-
sired final quality, and other factors, such as, availability of land for the
treatment plant and methods of sludge disposal.
More than two hundred mine drainage treatment plants are presently
in operation in Pennsylvania alone and many of the plants are operated by
captive coal companies. Because coal mining is a highly competitive indus-
try, most companies have shown reluctance to supply information on their
treatment costs for use in this study. Treatment costs are available for
some plants built for the Commonwealth of Pennsylvania and a few cost fig-
ures are available in the literature on mine drainage treatment for plants
operated by coal companies.
Since little actual cost data is available, a case history approach will
be used in describing selected lime neutralization plants, their characteris-
tics and costs, in order to get an idea of the present cost of mine drainage
treatment by lime neutralization. The case histories are as follows:
1. Duquesne Light Company, Warwick Mine No. 2
In 1969i the Duquesne Light Company began operating a 3 MGD mine
drainage treatment plant at the Warwick Mine No. Z, Greene County,
Pennsylvania. Figure 45 is a flow sheet for this plant. According to
Draper' ', mine drainage discharges from this Pittsburgh Seam mine
were consolidated to the area of lowest seam elevation and all mining in
this area was completed so that it could act as a natural sump.
Draper describes the plant operation as follows:
Three deep well turbine pumps with a capacity of about 4,400 gpm
were installed from the surface through boreholes into the area. The
raw mine water is discharged from the mine pumps into a flume, which
conducts it to a four million gallon raw water equilization pond. To pre-
vent leakage of raw water into the ground or into the nearby stream,
this pond was lined with over three feet of a compacted special imper-
vious clay trucked from some distance. The mine water is pumped from
the equalization pond into the reaction and aeration tank where it is re-
tained some ZO minutes.
Lime is delivered to the plant lime bin in pneumatic tank trucks of
approximately 2Z to*is capacity. When the pH control probe signals for
lime, the rotary and screw feeders under the bin start to feed lime into
the lime slurry tank, the water pump starts to put water into the same
tank and the lime slurry pump starts to pump milk of lime from the tank
-Z37-
-------
DUQUESNE LIGHT COMPANY
WARWICK MINE PORTAL NO. 2
MINE WATER TREATMENT PLANT
FLOW SHEET
PNEUMATIC TRUCK UNLOADING
SPLITTER BOX
OVERFLOW MIN6 pgups
RAW WATER J—1
PUMPS, ?L"ME-fl
EQUALIZATION
POND
UNDERFLOW TO
ABANDONED MINE
PRESENT PLANT
2100 gpm
After Draper, 1972
FIGURE 45
(42)
-238-
-------
into the mine water as it enters the reaction and aeration tank. When the
pH of the water rises to the preset level, the control shuts off both lime
feeders and both pumps.
The limed and aerated mine water discharges into a flume, passes by
the pH control probe and is discharged into the center well of the 200 foot
diameter earthen wall thickener. The overflow from this thickener is col-
lected in a trough near the periphery and conducted in a flume either di-
rectly to the stream or to a polishing pond, which will retain the water for
some 12 hours before discharging it to the stream. The underflow of the
thickener is pumped to a shaft or one of several boreholes for disposal in
an abandoned mine in the Sewickley Seam. The discharge from this seam
percolates to the Pittsburgh Seam, which is 100 feet below and from which
the raw water is pumped.
The total cost of the plant in 1969 was $582, 000 including the polishing
pond which was installed in December, 19&9. For the purpose of deriving
cost, a life of 10 years was assumed. The annual operating costs are about
19£ per thousand gallons. The mine drainage treated in 1971 had an aver-
age chemical analysis of: pH - 4.20, acidity - 1, 557 mg/1, and total iron -
573 mg/1 (Fe+2 - 424 mg/1).
The low cost of the plant operation can be attributed to: 1) sludge dis-
posal in abandoned mines, 2) completely automated operation of the plant
eliminating most of the labor costs and, 3) favorable topography and ground
conditions permitting construction of earthen walled tanks and ponds thus
eliminating costly construction of tanks of concrete or other structurally
strong walls.
2. Slippery Rock Creek Mine Drainage Treatment Plant
Probably the most interesting studies made to date on the effect of acid
mine drainage on an entire watershed, are those studies made for Slippery
Rock Creek. In addition to construction of a mine drainage treatment plant,
as a result of these studies, mine sealing and strip mine reclamation pro-
jects were completed. The latter projects are discussed in the appropriate
sections of this report.
In 1963, the basin was chosen by the Pennsylvania Department of Health,
Division of Sanitary Engineering (now Pennsylvania Department of Environ-
mental Resources, Bureau of Water Quality Management) for its first in-
tensive mine drainage study of a large watershed''*^). One of the reasons
for choosing Slippery Rock Creek was the complete change in water quality
that occurred downstream within months after the closing of a limestone
processing plant. Although the large number of mines in the watershed
had an adverse effect on stream quality, particularly in the headwaters
which were extensively mined, the highly alkaline discharge of waste water
from the limestone plant effectively neutralized the stream's acid load,
-239-
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making it alkaline downstream of the limestone plant discharge. Figure
46 shows the effect that closing the limestone processing plant had on
Slippery Rock Creek water quality.
In July, 1964, a high runoff occurring as a result of heavy rainfall
caused a serious fish kill in Slippery Rock Creek. The acid condition of
the stream during and immediately following the runoff was the direct
cause of death of fish and other aquatic life. Approximately two million
fish were killed over the entire length of the stream. It was concluded
that the slugs of acid responsible for the fish kill were flushed out of
swamps and impoundments in the extensively mined headwaters of North
Branch Slippery Rock Creek and that acid mine discharges from other
sources contributed to and prolonged the acid condition of the stream^ '.
Drainage from Slippery Rock Creek normally has a high natural alka-
linity because much of the watershed is underlain by 20 or more feet of
Vanport Limestone, a high calcium limestone. This availability of CaCC>3
is responsible for the chemical character of the mine drainage which is
weakly acidic in spite of the extensive mining which has occurred in parts
of the watershed. The mine drainage has a pH of around 4, acidities of
less than 100 mg/1, a low iron content, a manganese concentration equal
to or greater than iron, and a relatively high solids content when compared
to other water quality parameters. The mine drainage can be classified
as Class II and some of the tributaries may have Class III mine drainage
(Table 1).
The mine drainage treatment plant is located near the headwaters of
North Branch Slippery Rock Creek, which is in turn the headwaters for
Slippery Rock Creek drainage area, a watershed of some 400 square miles.
Tributaries which comprise less than 25 percent of the total watershed are
responsible for mine drainage pollution in the main stream, and the bulk of
this acid load is from the headwaters. More than 83 percent of the acid
mine drainage originates in abandoned mine workings.
The treatment plant is designed not only to improve the water quality of
the headwaters of North Branch Slippery Rock Creek, but also to minimize
the effect of acidity contributed by acid tributaries at some distance down-
stream. Table 34 showing treatment plant operating data for 1971 has a
tabulation of pH ranges in the stream below the treatment plant.
To accomplish the objective of making North Branch Slippery Rock Creek
a clean stream, it was necessary to neutralize all the acid mine drainage
and in addition, to remove all the insoluble by-products of that neutraliza-
tion. According to Lisanti, et al. (44>, the treatment of a major portion of
a stream watershed of three square miles and the removal of settleable
solids was not done before this undertaking.
-240-
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FIGURE 46
EFFECT OF THE CLOSING OF THE MICHIGAN LIMESTONE CO. PLANT
AT BOYERS IN DECEMBER 1957 ON WATER QUALITY IN
SLIPPERY ROCK CREEK
r 80T
60--
40--
20--
E
>s
0
KEY:
I. April 4,1951
2. May 11, 1955
3. February 25,1958
4. March 18,1963
5. June 17,1963
-20--
-40--
-60--
--80--
5
Above Limestone
Plant
Station 4 Boyers
I Mile Downstream
From Limestone Plant
Station 5 West of Boyers
5 Miles Downstream
From Limestone Plant
Station 7 Bovard
After Pennsylvania Department of Health, Division of Sanitary
Engineering, 1965(43)
-241-
-------
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-242-
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The flows, acidity, iron and manganese concentrations in the stream
may vary considerably with intensity of rainfall, therefore, average fig-
ures in design have little meaning. The peak flow of the stream is in the
order of 1, 550 MGD. The treatment plant objective is satisfied if 6, 000
Ib. /day of acidity is neutralized and as much as 50, 000 Ib. /day of solids
is removed from the neutralized water. The peak design flow rate was
set at 10 MGD and a median flow rate of 3 MGD was the basis of design
for the treatment plant. An average lime use of 1, 900 Ibs. /day was
estimated.
A flow diagram of the plant is shown in Figure 47 and the principal unit
processes are as follows:
a) Flow Diversion - A concrete dam to divert the peak design flow to the
plant. The dam, spillway and downstream channel are designed to take
peak stream flow, i«e., 3,450 cfs.
b) Equalization - A 2 million gallon impoundment lagoon serves to lessen
shock loads to the plant.
c) Neutralization - The stream flows by gravity to a well agitated tank
where lime slurry is automatically added under pH control. A back-
up pH and lime feed system is provided at the clarifiers center wall
for emergency use. Dry hydrated lime delivered in tank trucks is
made into a 30 to 35 percent by weight slurry by pneumatically un-
loading and mixing it with water in a storage tank provided with a
turbine mixer. The specific gravity of the slurry is controlled in a
dilution tank and fed to the treatment tank by means of proportioning
weirs.
d) Waste water Pumping - The head loss through the plant made it neces-
sary to lift stream water. This is accomplished with screw pumps
because they are essentially surge-free, will handle highly variant
flow rates, have non-clogging characteristics, and have an efficiency
of about 85 percent which remains relatively constant regardless of
variations in volume. The pumps are located between the flash mix
neutralization tank and the clarifier.
e) Clarification - A 75 ft, diameter, solids-contact type clarifier is used
which is capable of handling the varying loading and settling rates. A
200, 000 gallon lagoon is provided for emergency use.
f) Solids Handling - A 30 ft. diameter thickener is provided.to reduce the
water content of the clarifier sludge and to temporarily store the sludge.
The thickened sludge is pumped to one of two sludge lagoons, each
150,000 gallons, for further dewatering and storage.
-243-
-------
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g) Miscellaneous - Also included in the plant are: a polymeric flocculant
feeding system; filtration of treatment plant effluent for potable water
use; process water system which uses the plant effluent without further
treatment; compressed air system; and a sanitary sewage treatment
system.
The plant is manned by two operators during the day shift, usually one
during the second shift, and is unattended during the night shift, operating,
therefore, completely automatically.
Construction of the plant was completed in December, 1969 and the total
cost was $750, 000. Engineering costs were $53, 000. The annual operating
cost is about $51,000 (chemicals - $5,000, electricity - $7,000, wages -
$34,000, telephone and alarm services - $1,500, and the balance for mis-
cellaneous items.
3. Mountaineer Coal Company Mine Drainage Treatment Plant
Kosowski and Henderson* ' reported some of the design features and
capital expenditures for a mine drainage treatment plant at the Mountain-
eer Coal Company operation in Harrison County, West Virginia, The mine
drainage is an alkaline type discharge containing substantial amounts of
dissolved iron. A typical analysis of the influent is: pH - 6.5, alkalinity -
252 mg/1 and iron - 109 mg/1.
The treatment plant is designed to treat 0.72 MGD of mine drainage on
a 24 hour basis. A schematic flow sheet is presented in Figure 48. The
steep mountainous terrain in the immediate vicinity of the discharge to-
gether with other natural and man made obstacles, limited the available
land for a treatment plant to a single tract of land approximately 100 feet
below and 2, 000 feet away from the discharge.
The design features of the treatment plant are as follows:
a) The mine drainage flows from the Levi Moore borehole discharge in an
open ditch to a 300, 000 gallon earthen holding pond. The Georgia V-type
ditch is approximately 1,450 feet long, 16 feet wide and has a fall of 1/2
percent. The ditch also serves as an access road to the discharge pump.
b) From the holding pond, the mine drainage flows by gravity through a 10
inch pipe, down the side of the mountain, across a railroad track, and
across a creek, a total length of 520 feet to the treatment building.
c) At the treatment building the mine drainage is mixed with a lime slurry
prepared from bulk hydrated lime. The lime system is a standard unit
consisting of a pneumatic bulk lime storage bin of 30 ton capacity, a bin
shaker, screw feeder, lime slurry tank with mixer and a flash mix tank
with mixer.
-245-
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LEVI MOORE
PUMP
500 GPM
SETTLING LAGOONS
SLUDGE TRANSFER
SYSTEM
BINGAMON CREEK
""•^B"
SLUDGE LAGOON
MOUNTAINEER COAL CO. - WILLIAMS MINE
LEVI MOORE DISCHARGE
FIGURE 48
From Kosowski and Henderson, 1968* '
-246-
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d) The treated drainage then flows into an earthen aeration lagoon of about
100, 000 gallon capacity. Aeration is accomplished by spraying the water
into the air using a floating surface aerator.
e) The water then flows into two earthen settling lagoons arranged in series
where the insoluble iron compounds drop to the bottom of the lagoon while
the clear treated water overflows into the creek. The settling lagoons
have a combined capacity of almost 3 million gallons.
f) Flocculating chambers of reinforced concrete construction were built into
the inlet of each of the settling lagoons. The mechanical flocculator is a
standard unit, equipped with one five-blade flocculating turbine with sta-
bilizing ring and powered with a 1. 5 HP motor with variable speed drive.
Only one flocculator is used since it is physically moved from one settling
lagoon to the other. According to Kosowski and Henderson^ ', this is
a unique feature of the treatment plant design and probably the first of its
kind in the mine drainage field. The flocculating units are expected to re-
duce significantly the retention time, therefore, huge lagoons are not
needed to provide retention time for precipitation of iron compounds as
under normal circumstances.
g) A concrete sludge sump, with sludge pumps and piping was installed be-
tween the two settling lagoons to permit draining the contents and pump-
ing the sludge into a sludge lagoon.
h) Transfer of treated water from the treatment building to the aeration
lagoon, through the two settling lagoons and into the creek is by open
flared concrete flumes.
Another unique feature of this treatment plant is the installation of a com-
plete bulk lime system, even though the water is not acidic. The lime sys-
tem is used to obtain basic information on a large-scale treatment plant under
a variety of actual operating conditions and seasonal fluctuations.
The treatment facilities are capable of discharging treated mine drainage
containing no more than 10 mg/1 of iron, 30 mg/1 of aluminum, 200 mg/1 of
suspended solids and having a pH of 5. 5 to 8. 5.
The estimated capital expenditures at the Levi Moore treatment facilities
are $120, 000. A breakdown of these expenditures are:
a) Excavation and Grading $23, 000
b) Mechanical Equipment including Electrical 13, 000
c) Concrete, Piling, Erection of Steel and Bridge 59,000
d) Piping 6, 000
e) Sludge Pump and Piping 15, 000
f) Contingencies 4, OOP
Total $120,000
-247-
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4. Little Scrubgrass Creek Lime Treatment Plant
Based on the results obtained from research using the lime neutraliza-
tion technique with the "Operation Yellowboy" trailer, the Pennsylvania
Department of Mines and Mineral Industries (now part of the Pennsylvania
Department of Environmental Resources) decided that from a technical and
economic viewpoint, it would be most effective if neutralization of "low iron"
streams was accomplished using a fully automated neutralization process
(46,47).
A prototype treatment plant was designed and installed on Little Scrub-
grass Creek, Venango County, Pennsylvania. The plant did not include
any facility for liquid solid separation and this type of installation may
only be used in those cases where iron, aluminum, manganese and other
precipitable salts are present in low or insignificant quantities. There
does not appear to be a limit to the acid content of the mine water which
can be treated by the plant. It may be possible to operate a plant of this
type at sites where the stream velocity is such that any precipitates which
might form would be carried away and dispersed and would not create any
appreciable sedimentation or siltation problems.
The treatment plant operated 24 hours per day, 365 days per year and
treated the entire flow of Little Scrubgrass Creek. A schematic diagram
of the plant is shown on Figure 49. A float mechanism suspended from the
treatment plant into the creek rises and falls with the flow of the water be-
neath the plant. The stream flow is highly variable, but the quality of the
water remains nearly constant, therefore, the float mechanism needs only
to feed a quantity of lime directly proportional to the quantity of water flow
beneath the plant.
Similar plants were later constructed on other streams in Pennsylvania.
The capital costs have ranged from $40, 000 to $54, 000 depending on site
conditions and the specific requirements of the mine drainage.
The Little Scrubgrass Creek mine drainage has an iron content of approxi-r
mately 1 mg/1 and an average acidity of 68 mg/1. Neutralization is the only
treatment required of this stream. Aeration and dewatering were not war-
ranted. Costs for treating 1, 000 gallons of this specific water by lime
neutralization varied between $0.0068 (high flow) and $0.0573 (low flow).
Table 35 gives the monthly operating expenses for high and low flows.
-248-
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FIGURE 49
SCHEMATIC DIAGRAM
LITTLE SCRUBGRASS TREATMENT PLANT
VENANGO COUNTY, PENNSYLVANIA
Filter
Manhole
Line for
pneumatic
loading
From Charmbury, et al., 1968
(46)
-249-
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TABLE 35
LITTLE SCRUBGRASS CREEK LIME TREATMENT PLANT
Monthly Operating Expenses
Low Flow* High Flow**
Lime (Tons @ $15.65/Ton) $116.46 $557.50
Electricity 12.35 18.00
Man Hours 160.00 160.00
Repairs 5.50 5.50
Total $300.31 $741.00
*Summer-Fall Low Flow
**Winter-Spring High Flow
-250-
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5. Rausch Creek Mine Drainage Treatment Plant
A report submitted by the Anthracite Research and Development Com-
pany'^9) to the Pennsylvania Department of Environmental Resoruces in-
dicated there are 28 active mining operations on the east and west branches
of Rausch Creek together with six abandoned workings on the west branch
and an overflow from a mine pool on the east branch contributing to mine
drainage pollution of the stream.
A treatment plant was designed to treat the entire flow of Rausch Creek
located in Schuylkill County, Pennsylvania and construction is nearing com-
pletion. Figure 50 is a flow sheet of the treatment plant. Operators of
active mines contributing mine drainage to Rausch Creek are required to
pay a fee for operating expenses of the treatment plant.
The plant is designed for a flow of 10 MGD with a hydraulic capacity of
20 MGD and is provided with flash mixing, aeration, flocculation and clari-
fication, and thickening and polishing lagoons. Flows larger than 20 MGD
are automatically bypassed to Polishing Lagoon No. 1. In the event of such
large flows, facilities have been provided for addition of sodium hydroxide
to the polishing lagoon. Also the large holding capacity of the lagoons should
be able to absorb excess flows without any appreciable change in alkalinity
of the effluent. Provision has been made for trucking the sludge for final
disposal. The total construction cost of the project is $1,747,380 and engi-
neering design costs amount to an additional $314, 700. Since the plant has
not gone into operation yet, no operating costs are available(50).
6. Altoona Mine Drainage Treatment Plant
The treatment plant was designed by Gwin, Dobson & Foreman, Inc. ,
to eliminate acid mine drainage contamination of the area west of Altoona,
Pennsylvania and to improve the supply of potable water to the Altoona
Water System^51).
The major sources of potable water for the City of Altoona are located
in drainage areas west of the city. One stream, Kittanning Run is bypassed
because it is highly contaminated with acid mine drainage. Glen White Run
is contaminated to a lesser extent and is used for water supply. Sugar Run
was formerly used as a supply of potable water, but it is now highly con-
taminated by acid mine drainage. Two other drainage areas, Mill Run and
Homer's Gap, are not affected by mine drainage. A general summary of
water quality parameters of the streams is as follows:
-251-
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Acidity Iron Manganese
pH mg/1 rag/I mg/1
Glen White Run 3.8 60 5.5 3.3
Kittanning Run 2.9 420 70.0 11.0
Sugar Run 3.5 140 12.0 2.0
Mill Run 7.1 0 0.2 0.0
On the basis of laboratory and field investigations, it was decided that
these flows could be neutralized with a combination of lime treatment,
mixing, aeration and sedimentation. Additional studies were carried out
to determine the most feasible means of further treatment to render the
water potable for use in the Altoona Water System. The studies indicated
that a lime-soda process be used as it provided more flexibility and is more
adaptable to changing conditions which might occur. The combined water
treatment plant is under construction and has separate facilities for neu-
tralization and for softening and filtering a water supply. Neutralization
facilities are designed for a capacity of 15 MGD and the softening and fil-
tration portion is designed for a capacity of 7 MGD. A schematic flow
diagram is shown in Figure 51. Sludge will be disposed of in abandoned
deep mines.
The total construction cost of the project as contracted will be about
$4, 590, 000. Engineering design and supervision costs are about $172, 000.
The operating costs for the treatment plant, excluding capital ammortiza-
tion, are expected to be about $156, OOO^50).
7. Shirley Machine Company "Mixmeter"
A package slurry making and discharging plant is available in several
models with the trade name "Mixmeter" from the Shirley Machine Com-
pany, a Division of Tasa Corporation, Pittsburgh, Pennsylvania^ '. The
plant comes complete with pH recordings and controlling instruments. A
typical installation arrangement of one of the models is shown in Figure
52.
The Mixmeter provides continuous variable feed under automatic con-
trol and is capable of feeding 500 to 3, 000 Ibs. /hr. of hydrated lime in
slurry form with 20 percent solids. Plants with higher feed capabilities
have been designed and are available on order. The Mixmeter system
monitors the result of treatment downstream of the treatment plant, re-
lays a signal to the Mixmeter which responds to maintain the desired pH
of the effluent. In this concept the pH (a specific and constant pH) of the
treated effluent is the object of the treatment process. It automatically
compensates for volume and quality of the influent and the quality of neu-
tralizing agent being used.
Coal operators and other industrial sites in Pennsylvania, West Vir-
ginia and Ohio with acid pollution problems have a number of these plants
in operation.
-253-
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-254-
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Continuously Recording Controller
Charging Tank
Slurry Feed Hose
Raw Water
Suction Hose
Sump
Plan View
Continuously Recording Controller
pH Sensor
Charging Tank
Jfl
Water Line
End View
FIGURE 52
MIXMETER MODEL 65AE - TYPICAL INSTALLATION ARRANGEMENT
From Shirley Machine Company, Information Manual, 1972* '
-255-
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FLASH DISTILLATION PROCESS
Flash distillation is a vaporization and condensation process. The
feed in liquid state is heated to the vaporization point in an enclosed chamber
and subsequently flashed, in a series of chambers or columns, operated at
successively low pressures and temperatures (Figure 53). The basic process
has been utilized for years by the chemical industry for the processing of
petroleum, organic chemicals, and inorganic chemicals. The principal items
of equipment include evaporators, deaerators, air ejectors, heat exchangers,
pumps, air compressors and stream generating systems.
Within the last five years, the process has been investigated, evaluated
and used for processing saline and brackish waters for production of potable
water for domestic use. Recently the process has been investigated as a method
for the treatment of acid mine waters and at the same time for the production of
high quality potable water.
The basic idea of a concentrating evaporator is to reduce the volume of
contaminant ions by removing the H^O as vapor and leaving all the contaminants
behind. Drastic reduction in volume of material to be disposed of is the chief
benefit of this method, with the production of ultrapure water being a close sec-
ond.
Westinghouse Electric Corporation under a contract with the Coal Re-
search Board, Commonwealth of Pennsylvania, evaluated the flash distillation
process for treating of acid mine water(^'> 54, ", 56)< Preliminary tests were
made with a small scale pilot plant to determine the optimum operating condi-
tions and to assess the engineering and economics of the process as applied to
acid mine water. The data obtained from these tests were used to design a 5
MGD treatment plant. Capital investment and operating costs were estimated
for the plant based on the data from the pilot plant operation (Tables 36, 37,
and 38).
The operating costs in Tables 37 and 38 do not include capital cost
amortization and cost of sludge disposal. The demineralization plant was
scheduled to be completed about January, 1973. Since the new U.G.I, steam
plant was not scheduled to be completed until at least June, 1975, it would
have been necessary to operate the flash distillation plant for at least two years
on temporary oil-fired boilers.
The disposal of solid wastes from the Westinghouse Plant posed many
problems. Each day of full operation would yield about 150 tons of residue
which would be extremely caustic. Plans called for the disposal of this mat-
erial in a plastic-lined pit at the plant site but because of the chemical com-
position of the plant residue, the Pennsylvania Department of Environmental
Resources felt contamination of the groundwater could occur if the plastic
lining failed.
Because of projected excessive operating costs and questions about en-
vironmental impact, plans to construct a plant have been abandoned.
-256-
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Cooling Water
Product Water
<10 PPM
IDS)
1st Stage Heat
Rejection Unit
1st Stage Heat
Recovery Unit
2nd Stage Heat
Recovery Unit
2nd Stage Heat
Rejection Unit
1st Stage Recycle
Feed Heater
Steam
Ik k
* *
FeS04 Recovery
or Feed to
Wet Chemical
Recovery Unit
2nd Stage Recycle steam
(FeSO.-7
4"H2rj)
for
\izer/
>
i
-------
TABLE 36
MULTIPLE STAGE FLASH DISTILLATION
ACID MINE DRAINAGE TREATMENT PLANT
Cost Estimate
(1971)
1. Principal Items of Equipment
Evap. & Brine Heater $ 6,024,000.00
Air Ejector 10,000.00
Pumps and Drivers 425, 124. 00
Misc. Tanks 50,000.00
Crystalizer
Evap. Field Erection 567,000.00
2. Process Facilities
Site Development 567,000.00
Piping 655,200.00
Electrical 459,527.00
Instruments 195,300.00
Insulation 126,000.00
Painting 50,400.00
Building 264, 600. 00
Equipment Erection 347, 760. 00
3. Other Plant Costs
Engineering (Purchases) 577,041.00
Interest During Construction
Start-Up Expenses 214,200.00
Engineering W 446, 000. 00
4. Other Facilities
AMD Pumping System 597, 996. 00
Cooling Tower 432,180.00
Temporary Boiler (s) 1,007,760.00
Prod. Water Post-Treat 63,000.00
Sludge Disposal 6, 300. 00
Plant Cost Total 13,086,388.00
5. Operation and Maintenance 447, 000. 00
6. Plant + Operational Cost 13,533,388.00
7. Contingency on Prototype Plant 666,612.00
8. Grand Total Plant + Operation for 1st Year $14, 200, 000. 00
After Westinghouse Electric Corp.,
-258-
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TABLE 37
SUMMARY OF OPERATING COSTS
Plant Capacity = 1, 750, 000 KGAL/year
1971 Engineering Cost Estimate
Yearly Cost/1000 Gal.
Direct Operating Costs
1. Steam Cost $ 505,050.00 28.
2. Electric Cost 344,064.00 19.
3. Maintenance 69,600.00 4.
4. Oper. Labor/Supv. 93,600.00 5.
Subtotal $1,012,314.00 58.
Indirect Operating Costs
1. General and Administrative
Payroll $ 28,080.00 1.
2. Payroll Extras for Op. Labor 12,500.00 .
Subtotal $ 40,580.00 2.3£
Total $1,052,894.00 60. 3£
"Interim Cost of Water" is presented in Table 38. This cost can be anticipated
until operation with the U.G.I, plant commences.
After Westinghouse Electric Corp. ,
-259-
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TABLE 38
INTERIM OPERATING COSTS
1971 Interim Cost Estimate
Yearly Cents/1000 Gal.
Direct Operating Costs
1. Steam Cost $3,968,800.00 226.
2. Electric Cost 602,760.00 34.
3. Maintenance 75,000.00 4.
4. Operating Labor and
Supervision 126,880.00 7.
Subtotal $4,773,440.00 272.
Indirect Operating Costs
1. General and Administrative Costs $ 125,000.00 7. l
2. Payroll Extra for Operating Labor 17,472.00 1.0
Subtotal $ 142,472.00 8. l£
Total $4,915,912.00 280.7^
$2.81
After Westinghouse Electric Corp., 1971 '
-260-
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ION EXCHANGE PROCESSES
The basic process for the treatment of acid mine water by ion exchange
(deionization) consists of the reaction of metal salts and hydroxides in water
with specific anionic and cationic resins.
Various forms of ion exchange processes can be used to remove un-
desirable constituents 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. There is an
indication that the sludges and other residues produced by this process may
be more amenable to disposal than those produced by neutralization.
Burns and Roe, Inc. , in a proposal to the Pennsylvania Department
of Environmental Resources'-5 ' >, describe the two fundamental reactions in-
volved in the ion exchange process. They can be expressed by the following
equilibrium equations:
cl + Rfc2+ = c2+ + RX'C^
AX- + R2+A2~ = A2~ +RZ+AI"
Where C^ , C2 are cations of different species
A,", A ~ are anions of different species
R!~, RO are cationic and anionic exchange materials.
The normal sequence in the treatment of industrial waters by the ion
exchange process is to pass the flow first through a cation exchanger and then
through an anion exchanger. If softening is the desired objective, the following
reaction applies:
Ca++ Ca++
Mg++ Mg++
2 Na
After the resin is exhausted; i.e., all of the exchange sites have been
used, it is regenerated with concentrated salt solution as follows:
Ca++
l +2 Na+— ++ >+Na2R1
Mg Mg J
The calcium and magnesium ions are contained in the waste regenerant
as the chlorides. The treated water contains sodium ions and all of the anions
originally present.
-261-
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Applied to mine drainage, the softening reaction has several limitations.
The process removes none of the anions, specifically, sulfates, and the waste
regenerant contains the same cations, still in soluble, albeit more concentrated,
form. A third limitation is that the ion exchange reactions involving iron and
manganese cations may not be as easily reversible as those involving calcium
and magnesium. Finally, the total waste problem is actually aggravated by the
load represented by the regenerant.
If_ the conventional demineralization process is utilized, the reactions
are as follows:
2 Na
Ca
Mg
Fe
Mn
Al
SO4
2 Na
Ca
Mg
Mn
Al
H2S04
2HC1
2 H2O
H2S04 S04
>+ 2 R2OH -R2 <^
2 HC1 J [ C12
The regeneration reactions are as follows:
2 Na
Ca
Mg
Fe
Mn
HS0
SO,
C12
+ 2 NaOH
2 Na
Ca
- Mg
Fe
Mn
2 Na
SO
SO,
R(OH)2
The limitations of the normal demineralization sequence are the same
as those of the softening process, plus the relatively high cost of the regener-
ation chemicals, which makes the process uneconomical as compared to alter-
nate processes as soon as the total solids level exceeds 500-1,000 mg/1.
The criteria used in selecting ion exchange processes for the treatment
of mine drainage are therefore the following:
1. To convert the contaminating soluble ions present in mine drainage
into insoluble forms.
2. To achieve this conversion either utilizing low cost chemicals as
regenerants or to develop process sequences which allow for the
recovery and reuse of the regenerant.
-262-
-------
A promising process for treatment of acid mine drainage wastes was
described by Pollio and Kunin'^°'*. The principal process steps are expressed
in these reactions:
Treatment:
M (SO4) + 2 RHCO3 -R2SO4 + M(HCO3)2
Regeneration:
R2SO4 + 2 NH4OH 2 ROH + (NH4)2SO4
2 ROH + 2 H2CO3 *• 2 RHCO3 + 2 H2O
The ion exchange process is followed with aeration and coagulation with
lime to precipitate iron, manganese and aluminum and to reduce calcium and
magnesium hardness.
The advantage of this process is that most of the metallic sulfates are
converted into soluble bicarbonates which pass through the resin bed without
forming precipitates. The insoluble salts then are formed downstream in the
aerator and softener and are removed by coagulation and sedimentation. The
regenerants used in this process are ammonia and carbon dioxide, both of
which are relatively low cost bulk chemicals. Furthermore, the process ap-
pears to be suited to either regenerant recovery and reuse or the development
of marketable by-products from the spent regenerant. The process therefore
has the potential of meeting the objectives of elimination of pollution and of the
ultimate disposal of the waste products.
Another promising ion exchange process for treatment of acid mine
drainage waters takes advantage of sulfate-bisulfate equilibria and is currently
being explored for processing brackish waters. This process** uses 1) a strong
acid cation exchange resin, and 2) a strong base anion exchange resin which
operates on the sulfate-bisulfate cycle.
The fundamentals of this process are as follows: In the first step, the
water is contacted with a strongly acidic ion exchange resin, converting the
salts to their corresponding free acids. These are passed through the sulfate
form of a strong anion exchanger. The divalent sulfate counter ions remove
hydrogen ions from the water and are converted to the monovalent bisulfate
ion. This frees half the anion exchange sites for absorption of anions from
solution. The water is thereby effectively demineralized. For example, a
solution of ferrous sulfate passed through the resin acids will react as follows:
*Desal Process^
**Sul-biSUL process1
-263-
-------
Cation Exchanger
FeSO4 + 2 RH .^ * R2Fe + H2SO4
Anion Exchanger
H2SO4 + RzSO4 «. 2 RHSO4
Regeneration is a simple process. The anion resin is regenerated with
water, or water made slightly alkaline with lime, which, because of its higher
pH, reverses the sulfate bisulfate reaction:
H20
2 RHSO4 - - RzSO4 + H2SO4
The liberated acid is partially recovered using it to regenerate the
cation resin.
R2Fe + H2SO4 - «- 2 RH + FeSO4
The regenerant chemicals are inexpensive; i.e., sulfuric acid and
lime. This process is reportedly more efficient at higher salt concentrations,
and it could be very economical if the natural acidity of mine waters could be
used as a source of regeneration acid. It seems possible that this process
could be more economical than bicarbonate cycle processes for certain acid
mine drainage waters. Therefore, the choice of ion exchange process would
depend on the concentration and composition of the acid mine drainage water
to be processed.
Burns and Roe, Inc.^'» "', designed an ion exchange treatment plant to
treat acid mine drainage at Hawk Run near Philipsburg, Pennsylvania. The plant
utilizes the "Modified desal process"® developed by Rohm and Haas Company,
Philadelphia, to remove mineral acidity. This is followed by aeration, softening,
and filtration to remove iron, other metals and hardness to produce water meet-
ing the U.S. Public Health Service standards for drinking water. A schematic
flow diagram of the treatment plant is shown on Figure 54. Burns and Roe, Inc.' '
gives a summary of operating data and the design water quality as shown in
Table 39.
The estimated construction cost of the plant is about $2,485,000 including
engineering design costs.
Chester Engineers^*' °*> designed a 0.5 MGD ion exchange treatment
plant for Smith Township about 20 miles west of Pittsburgh. The capital costs
of the plant is borne solely by the Commonwealth of Pennsylvania and the Smith
Township Municipal Authority in conjunction with the Smith Township Supervisors
will operate and maintain the plant.
-264-
-------
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TABLE 39
SUMMARY OF OPERATING DATA AND DESIGN WATER QUALITY
Summary of Operating Data
Nominal Plant Capacity, Normal Operating Conditions 500, 000 GPD
AMD Water Treated 684, 000 GPD
In-Plant Use and Waste 64, 000 GPD
Treated Water Produced 620, 000 GPD
Maximum Output of Ion Exchange Resin When Supplied
with AMD Water of Design Conditions 820, 000 GPD
Chemical and Fuel Requirements
Ammonia (5% Makeup) 160 Lb. /Day
Carbon Dioxide 6, 180 Lb. /Day
Lime 6,430 Lb. /Day
Fuel Oil 350 GPD
Waste Products (Dry Basis) 19, 160 Lb. /Day
Design Water Quality
Sulfate
Hardness
Total Iron
pH
Total Solids
AMD Feed
1, 000 mg/1
550 mg/1
250 mg/1
3 - 4
1,000 mg/1
Product
50
70
0.3
8.5
300
mg/1
mg/1
mg/1
mg/1
-266-
-------
The water in Dinsmore Reservoir, the source of potable water for the
Township, is alkaline but contains more than 1, 000 mg/1 of sulfates, largely
calcium sulfate, and several hundred mg/1 of carbonates. Mine drainage from
strip mines within the area flows through limestone and calcareous shales.
This results in the production of a calcium sulfate near -neutral water product
as the acidity and iron is removed. A typical analysis of raw water in the res-
ervoir would indicate a pH of 6.5 to 8.4, sulfates from 400 to over 1, 300 mg/1,
and total dissolved solids of 1, 500 to 2, 000 mg/1.
Prior to the installation of the ion exchange treatment plant, raw water
was treated by coagulation to remove turbidity, some soda lime softening fol-
lowed by filtration and chlorination. Hardness was only partially removed by
this treatment and the high total dissolved solids discouraged industrial use.
Water treatment costs using the lime and soda ash process was about 0.50£/
1, 000 gal. and it is believed that water treatment costs using the new ion ex-
change process will be brought down to 0.20^/1, 000 g
The ion exchange process for the treatment plant is based on
technology of the Dow Chemical Company and on a resin handling system devel-
oped by Chemical Separations, Inc. It employs two ion exchange steps and an
intricate method for regenerating and transporting ion exchange resins. Figure
55 is a flow diagram of the process. A product water with a pH of 8 to 9, a
dissolved solids concentration of less than 500 mg/1, and a total hardness of
150 mg/1 should result from treatment. The total capital cost of the project
including engineering design is estimated at $730,000.
The Culligan International Company'"^) made an extensive study for the
Environmental Protection Agency on treatment of mine drainage using ion ex-
change processes. They studied two complete processes in detail for production
of potable water. One process, the utilization of a strong acid cation exchanger
(H+ form) with a weak base anion exchanger (free base form) is a conventional
ion exchange process which has never been applied to the treatment of mine
drainage. The process utilizing a weak base anion in the bicarbonate form with
lime treatment had been studied before. Their study compared the two pro-
cesses. It is demonstrated that these processes are capable of producing a
potable effluent from acid mine drainage and that the chemical costs are about
the same. Wastes from the conventional ion exchange process will contain acid
materials while the bicarbonate form-weak base process does not. Three plant
sizes for each process are being designed for production of 0.1, 0.5 and 1,0
MGD of potable water so that a comparison can be made of each of the two pro-
cesses.
-267-
-------
-268-
-------
REVERSE OSMOSIS PROCESS
A concise definition of the fundamentals of reverse osmosis is included
in "Treatment of Acid Mine Drainage by Reverse Osmosis, " a study by Rex
Chainbelt, Inc. for the Environmental Protection Agency^ '.
"Osmosis occurs if two solutions of different concentrations in the
same solvent are separated from one another by a membrane. If the mem-
brane is semipermeable, i.e., permeable to the solvent and not to the solute,
solvent flow occurs from the more dilute to the more concentrated solution.
This solvent flow continues until the two solutions are of equal concentration
or the pressure on the more concentrated side of the membrane rise to a value
called the osmotic pressure. If a pressure in excess of the osmotic pressure
is applied to the more concentrated side of the membrane, the solvent can be
caused to flow into the more dilute solution. This is termed reverse osmosis."
Golomb and Besik' "°) describe five broad categories of osmotic mem-
brane modules as follows:
Tubular Units - There are several design concepts of tubular modules
on the market. Their chief advantage over other systems is that they can
handle liquids containing suspended particles or dissolved substances likely to
precipitate out as the feed solution becomes more concentrated. In the tubular
unit, provision is made for maintaining a good flushing action throughout the
system during operation. As the solution becomes more concentrated, it is
often possible to prevent fouling or plugging of the membrane simply by ad-
justing the proper hydrodynamlc conditions. This is an easy operation in
tubular systems, but hardly possible in others. Nevertheless, there are also
some disadvantages: 1) the large number of connectors with the resulting ex-
pense in making and assembling the array; 2) the small membrane surface
area/unit volume ratio; 3) the necessity for enclosing the tube exteriors to
protect the purity of the permeate; and 4) the expensiveness of the support
media.
Spiral-Wound Units - Developed by Gulf General Atomic Co. , the spiral-
wound unit consists of a "sandwich" arrangement consisting of two layers of
membrane, with a porous backing material at the center, at one end of which
is a perforated plastic pipe. The edges of the membrane are sealed, with the
porous backing material inside the resulting envelope, which with suitable mesh
spacers is rolled spirally around the central pipe. The whole is placed inside
a cylindrical pressure container, thus completing the modular unit. Typically,
several modules can be placed in series. The feed liquid flows axially, and as
water permeates the membrane it flows through the porous backing material to
the central pipe which acts as collector for the product water. The concentrated
solution continues to flow axially through the roll, emerging at the mesh spacer
gaps at the other end.
-269-
-------
A principal advantage of this design is that it has a high membrane
surface area/unit volume ratio compared with the tubular configuration.
Disadvantages in comparison with tubular units are: 1) severe problems in
handling high-solids feed; 2) short feed flow paths; 3) high pressure losses;
and 4) difficulty in recirculating concentrate.
Plate and Frame Units - The plate and frame concept, the earliest
design of RO unit, has an obvious similarity to the filter press, and provides
a convenient solution to the pressure-containing problem. A system of this
type has been developed by Aerojet-General Corp. It is particularly attrac-
tive for small, low-pressure plants.
The membrane is supported on a flat circular plate, and plates are
stacked on top of each other. Product water emerges at the edge of the plates
in the smaller units; in the larger units (over 1, 000 gpd* capacity) product
water is channelled to a central shaft. Feed and product liquid streams are
kept separate by O-ring seals. Turbulent flow of the feedstream. is induced
by means of baffles located near the membrane surfaces.
The following disadvantages can be ascribed to the plate and frame
design: 1) expensive to install and maintain (labor costs); 2) distribution and
short circuiting problems; 3) narrow flow channels; 4) multiple membrane
handling, which increases the probability of failure; and 5) low surface area/
unit volume ratio. Notwithstanding these limitations, large numbers of com-
plete units have been used for water purification on a scale up to 40, 000 gpd.
Plate and Frame (Ultrafiltration) Units - Dorr-Oliver, Inc. has devel-
oped a somewhat unique ultrafiltration module, less costly and easier to main-
tain than other devices now available in regard to membrane replacement. The
membrane is supplied in the form of replaceable cartridges, which are inserted
into a polyester/fiberglass molded rectangular shell-and-cover arrangement.
The unit has typical operating pressures of 10-50 psi. The Dorr-Oliver unit
utilizes high flux, non-cellulosic anisotropic membranes, developed by the
Amicon Corp., and tailor-made for retention of large molecules and colloids.
These membranes are well-suited to operation under more strongly acidic or
alkaline conditions than the cellulosic membranes can withstand, and also at
higher temperatures. Currently, this system is being developed for industrial
and domestic wastewater purification.
Hollow-Fiber Units - A somewhat novel approach to RO equipment is
being pursued by the DuPont Co. and by Dow Chemical Co. , who have pioneered
the use of fine hollow fibers as osmotic membranes.
Modules based on this concept contain an astronomically large number
of hollow filaments, ca. 50/* o.d. and 25^, i.d., assembled into a cylindrical
bundle, the open ends of which have been potted into a plug of resin serving as
*Gallons of Permeate per Day
-270-
-------
a header. This bundle is inserted into a cylindrical shell which serves as
a pressure vessel. Pressurized liquid is pumped into the shell side of the
assembly, permeate being collected from the ends of the hollow fiber bundle.
These units contain an enormous membrane surface area/unit volume ratio,
so that high intrinsic membrane permeabilities (in terms of gfd) are unim-
portant. Present systems are designed primarily for water demineralization.
Dow's fibers are spun from cellulose acetate; DuPont's from nylon and other
polymers.
Advantages of the hollow fiber configuration are: 1) enormous surface
area/unit volume ratio; and 2) the hollow fibers withstand the high operating
pressures required for RO and eliminate the need for space-consuming porous
support media essential to other module designs.
The disadvantage of this configuration is that it is not applicable where
an appreciable level of suspended solids is present in the feed solution. Fil-
tration is necessary to prevent clogging of the fiber bundle.
The DuPont hollow-fiber unit, based on nylon fibers, is operational in
the pH range 1.5 - 12.0, as compared with the recommended pH range 3-8
for modules utilizing cellulose acetate membranes.
A reverse osmosis plant for treating acid mine waters would consist of
a raw water intake, pumps, and filters for removal of particulate matter from
the raw water. Filter effluent passes to the reverse osmosis pressure vessel
and is exposed to the membrane cells. The concentrated brine after completing
its circuit through the reverse osmosis unit passes to a collection pond or tank
for disposal by deep well injection or by a lime neutralization process. Product
water is collected and held in storage tanks for ultimate utilization.
A plate and frame type reverse osmosis unit was briefly operated on
acid mine waters at two mines near Kittanning, Pennsylvania in 1965, by Gulf
General Atomic, Inc.' ' under the sponsorship of the Office of Saline Water in
cooperation with the Bureau of Mines. The spiral-wound configuration was then
extensively tested by Gulf General Atomic, Inc.^ ' at the Environmental Pro-
tection Agency mine drainage treatment laboratory in Norton, West Virginia.
These tests showed utilization of reverse osmosis with acid mine drainage feed
was feasible and that the product water was of potable quality. On the basis of
the test results, it was reasonable to conclude the process would be most appli-
cable for Class I acid mine waters which are highly acidic and have low pH's,
and that Class III mine waters which contain no iron and are alkaline would be
suitable.
The principal advantage of reverse osmosis for acid mine drainage treat-
ment is the recovery of potable water as a byproduct.
-271-
-------
Disadvantages are: 1) high cost of acid mine drainage treatment and
brine disposal; 2) reverse osmosis by itself does not eliminate acid mine
drainage water; 3) fouling of membranes with consequent necessity of periodic
replacements; 4) operation with the acid solutions required for the prevention
of scaling makes it necessary to construct the plant of corrosion resistant
materials which significantly increase capital cost requirements; and 5) pre-
filtration of acid mine drainage is required for feed to a reverse osmosis
process unit.
Cyrus Wm. Rice and Company in their report to the Appalachian Reg-
ional Commission^*/ developed tabulated costs and plots based on the studies
of Keilin(69) and Schroeder, et al.C^O). Tables 40 to 52 and Figures 56 to 59
show the tabulated costs and cost curves as worked out by this company. No
attempt has been made to update these cost figures for the present study be-
cause of rapid technological developments in the reverse osmosis field with
resulting reductions in the cost of RO units.
Cyrus Wm. Rice and Companyl'*!) list the elements of capital and op-
erating costs which must be considered in design, construction and operation
of reverse osmosis treatment plants.
Elements of Capital Cost
1. Principal Items of Equipment
a) Reverse Osmosis Cells
b) Filters
c) Pumps
d) Pressure Vessels
2. Process Facility Costs
a) Site Development
b) Piping
c) Electrical
d) Instruments
e) Buildings
f) Others
3. Other Plant Costs
a) Contingencies
b) Engineering
c) Interest during construction
d) Startup expense
e) Cost of Site
-272-
-------
4. Other Facilities Costs
a) Raw Water Intake
b) Product Water Storage
c) Deep well or lime neutralization
facilities for brine disposal
Elements of Operating Costs
(Excluding Taxes and Insurance)
1. Reverse Osmosis Processing
a) Power
b) Membrane Replacement
c) Operating Supplies
d) Operating and Maintenance Labor
e) G & A and Overhead
f) Fixed Charges
(Amortization and Interest)
2. Lime Neutralization Brine Disposal
a) Hydrated Lime
b) Limestone
3. Deep Well Brine Disposal
-Z73-
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TABLE 42
ESTIMATED CAPITAL COSTS FOR REVERSE OSMOSIS PROCESS WITH
LIME NEUTRALIZATION FOR BRINE DISPOSAL IN THOUSANDS OF
DOLLARS (FOR A AND B SERIES CASES CITED IN TABLES 40 & 41)
Total RO plant
(Items I-IV, Table B)
Total Capital Cost
for Lime Neutralization
Facility^
Total
A-.l A-l A-10 B-.l B-l
B-10
162 917 6600 261 1485 10,690
200 240 480 200 290 1,000
362 1157 7080 461 1775 11,690
Note:
5. Costs obtained from curves developed by Cyrus Wm. Rice & Co. , 1969
From Cyrus Wm. Rice & Co.,
(41)
-276-
-------
TABLE 43
ESTIMATED CAPITAL COSTS FOR REVERSE OSMOSIS PROCESS
WITH DEEP WELL BRINE DISPOSAL IN THOUSANDS OF DOLLARS
Special Case-A^ Special Case-B7
Total RO plant
(from plotted data) 560 416
Total Capital Cost
of Deep Well Brine
Disposal Facility 600 600
Total 1160 1015
Note:
Special Case A is based upon data obtained from as follows:
TDS = 1500 ppm, well depth = 4000 feet, total cost basis =
$150/ft., injection pressure = 700 psi, injection flow = 100 gpm.
Data developed on the foregoing is as follows: AMD treated =
720, 000 GPD (from 1500 ppm inlet solids and 100 GPM disposal
flow), product flow = 575, 000 GPD, Total well cost = $600, 000.
Special Case B is based upon data in 6 above with the exception:
TDS = 5000 ppm. Data developed on the foregoing is as follows:
AMD treated = 358, 000 GPD (from 5000 ppm inlet solids and 100
GPM disposal flow), Product flow = 214, 000 GPD, Total well
cost = $600,000.
From Cyrus Wm. Rice & Co.,
-277-
-------
TABLE 44
ESTIMATED CAPITAL COSTS VS. CAPACITY FOR
REVERSE OSMOSIS PROCESS WITH DEEP WELL BRINE DISPOSAL
(FromSchroeder, et al. , 1966(70) )
Product Flow
in gpd Capital Cost
100,000 $248,000
1,000,000 $1,407,000
10,000,000 $10,120,000
Total Dissolved Solids in Feed - 1638 ppm
From Cyrus Wm. Rice & Co.,
-278-
-------
E 45
OR REVERSE OSMOSIS PROCESS
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TABLE 46
ESTIMATED OPERATING COSTS FOR REVERSE OSMOSIS PROCESS
WITH LIME NEUTRALIZATION FOR BRINE DISPOSAL IN
DOLLARS PER THOUSAND GALLONS OF AMD TREATED
(FOR CASES CITED IN TABLES 40 & 42 USING HYDRATED LIME)
A-.. 1 A-l A-10 B-. 1 B-l B-10
Sub-Total
(Table A) .785 .137 .080 .618 .122 .078
Neutralization
Operating Costs .182 .180 .161 .605 .595 .500
Fixed Charges .507 .162 .099 .484 .186 .123
Total 1.474 .479 .340 1.707 .903 .701
TABLE 47
ESTIMATED OPERATING COSTS FOR REVERSE OSMOSIS PROCESS
WITH LIME NEUTRALIZATION FOR BRINE DISPOSAL IN
DOLLARS PER THOUSAND GALLONS OF PRODUCT WATER
(FOR CASES CITED IN TABLES 40 & 42 USING HYDRATED LIME)
A-. 1 A-l A-10 B-. 1 B-l B-10
Total 1.840 .599 .425 2.856 1.510 1.171
From Cyrus Wm. Rice & Co., 1969^ l'
-280-
-------
TABLE 48
ESTIMATED OPERATING COSTS FOR REVERSE OSMOSIS PROCESS
WITH LIME NEUTRALIZATION FOR BRINE DISPOSAL IN
DOLLARS PER THOUSAND GALLONS OF AMD TREATED
(FOR CASES CITED IN TABLES 40 & 42 USING LIMESTONE)
A-. 1 A-l A-10 B-.l B-l B-10
Sub-Total
(Table A) .785 .137 .080 .618 .122 .078
Neutralization
Operating Costs .140 .139 .121 .312 .305 .230
Fixed Charges .507 .162 .099 .484 .186 .123
Total 1.432 .438 .300 1.414 .613 .431
TABLE 49
ESTIMATED OPERATING COSTS FOR REVERSE OSMOSIS PROCESS
WITH LIME NEUTRALIZATION FOR BRINE DISPOSAL IN
DOLLARS PER THOUSAND GALLONS OF PRODUCT WATER
(FOR CASES CITED IN TABLES 40 & 42 USING LIMESTONE)
A-.l A-l A-10 B-.l B-l B-10
Total 1.791 .548 .375 2.360 1.023 .720
From Cyrus Wm. Rice & Co.,
-281-
-------
TABLE 50
ESTIMATED OPERATING COSTS FOR REVERSE OSMOSIS PROCESS
WITH DEEP WELL BRINE DISPOSAL IN
DOLLARS PER THOUSAND GALLONS OF AMD TREATED
(FOR SPECIAL CASES A & B IN TABLE 42)
Special Case A Special Case B
Power (@ $.007/kw-hr)14 .063 .069
Membrane replacement . 006 . 009
Operating supplies . 005 . 007
Operating and maintenance
labor .095 .190
G and A and overhead . 030 . 067
Well maintenance .025 .051
Fixed Charges .282 .497
Total .506 .890
TABLE 51
ESTIMATED OPERATING COSTS FOR REVERSE OSMOSIS PROCESS
WITH DEEP WELL BRINE DISPOSAL IN
DOLLARS PER THOUSAND GALLONS OF PRODUCT WATER
Special Case A, / Special Case Bj
Total .634 1.49
Note:
14. Deep well injection pump power added to reverse osmosis power.
15. Based upon $6, 000/year maintenance estimated by
16. Product flow = 575, 000 GPD
17. Product flow = 214, 000 GPD
From Cyrus Wm. Rice fe Co.,
-282-
-------
TABLE 52
ESTIMATED OPERATING COSTS VS. CAPACITY FOR
REVERSE OSMOSIS PROCESS WITH DEEP WELL BRINE DISPOSAL IN
DOLLARS PER THOUSAND GALLONS OF PRODUCT WATER
(FROMSCHROEDER, et al., 1966(70))
Product Flow
in gpd Cost
100,000 $2.57
1,000,000 $1.09
10,000,000 $0.77
Total Dissolved Solids in Feed - 1638 ppm
From Cyrus Wm. Rice & Co.,
-283-
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Studies were conducted by Rex Chainbelt, Inc. and the Environmental
Protection Agency(°^» ' *• '^» '3) with tubular, hollow fiber and spiral-wound
systems of reverse osmosis and the following conclusions were reached:
1. Under proper operating conditions, reverse osmosis can be used to treat
ferrous iron acid mine drainage without major iron and calcium sulfate
fouling problems.
2. Flux declines observed during optimized flow schemes were tolerable for
all three units but the spiral wound and hollow fiber were slightly superior
in flux stability.
3. Although salt rejections were near 99 percent for all three units, product
water would still need further treatment for iron and manganese removal
and pH adjustment before potable standards could be met.
4. An intolerable flux decline rate was observed for the tubular system when
high salt passage (1.5 percent) membranes were utilized, while lower salt
passage (0.4 percent) membranes had significantly improved flux stability.
5. Oxidation of ferrous iron by bacteria can be inhibited by ultraviolet disin-
fection and/or by lowering the pH to 2.9 by acid injection.
6. Water recovery was limited to slightly above 75 percent due to calcium
sulfate precipitation which occurred when brine CaSO^ molar solubility
product values were in the range 35-50 x 10~5.
7. No observable loss in membrane salt rejection capability occurred during
a six-mo nth study.
8. The tubular system had significantly lower productivity and higher initial
cost as compared to the hollow fiber and spiral-wound system in this
application.
Table 53 shows the typical raw water quality characteristics of the
Mocanaqua discharge at Mocanaqua, Pennsylvania, where the three systems
of reverse osmosis were evaluated. Tables 54 and 55 compare the water
production capabilities and relative cost of the three reverse osmosis systems.
-288-
-------
TABLE 53
TYPICAL RAW WATER QUALITY CHARACTERISTICS OF
MOCANAQUA DISCHARGE
pH
Conductance
Acidity
Calcium
Magnesium
Total Iron
Ferrous Iron
Aluminum
Sulfate
Manganese
Silica
TDS
Dissolved Oxygen
Temperature
3.4
1100 Mmhos/cm.
230 mg/1 as CaCO3
120 mg/1
90 mg/1
80 mg/1
68 mg/1
11 mg/1
800 mg/1
15 mg/1
10 mg/1
1200 mg/1
< 1 mg/1
54° F.
-289-
-------
TABLE 54
Comparison af Uater Production Capaoilities
System
Spiral Wound
(Phasp I)
Spiral Wound
(Phase II)
hollow Fiber
(Phase II)
Tubular
(Phase II)
Pressure
Vessel
Volume
ft3
1.13
1.13
0.65
0.63
Enclosed
Membrane
ftraa ft2
150
166
1500
16.9
Memarana
Packing
Density
ft2/ft3
133
165
2308
26. 6
Aug. Flux
GF^O S
77° F &
(.00 psi
net
(19.28 @ 600)
12.86
12.31
2.1.6
(15.60 @ 600)
10.1.0
Total Vssael
Flux pe."1 Day
Gal/Day
® 77" F &
1*00 psi net
(2892 *S 600)
1929
2290
3720
(26<4 e 600)
Output psr Cubic Foot
of Vassal Volume
per day @ 77°F
& COO psi net
(2559 S 600)
1707
2026
5723
(1.18 S 600)
176 | 280
8
i
per Win. @ 77"F
S tOQ psi nei;
(1.76 & 600)
1.19
l.<4l
3.97
(0.29 8 600)
0.19
TABLE 55
Relative Cost
System
Spiral Uound
Phase I
Spiral Wound
Phase II
Hollow Fiber
Phase II
Tubular Phase II
Cost for One
Pressure Vessel
and Membrane
» 850.(11)
1 850.(11)
J100D.(1Z)
J 2SS.(13)
Obseruea Output (Gal. per
Vessel per day @ 77° F
X Indicated Net Pressure)
2892 e 600
2290 8 UOO
3720 9 <.00
261* @ 600
Initial Cost
per Unit Out-
put (^al/day)
80.29
$0.37
$0.27
$1.00
From Wilmoth, et al. , 1972(73)
-290-
-------
In a report for the Environmental Protection Agency, Rex Chainbelt,
Inc.(' ) worked out cost estimates for a 0.75 MOD reverse osmosis acid mine
drainage treatment plant. Figure 60 shows the flow sheet used for the cost
estimates. The following assumptions were made to arrive at costs:
1. Hollow fiber RO modules are utilized.
2. RO product water capacity is 0.75 MGD,
3. Chemical additive costs are based on field testing results.
4. Diatomaceous earth filtration is utilized.
5. No costs for buildings or land are included.
6. The product water from the plant meets USPHS standards.
7. No costs are included for disposal of residuals.
8. Operating manpower includes a plant manager and a three man crew.
(Total salary and administrative costs - $50,000 per year.)
9. Power costs are 1.0^/kwh.
10. Chemical additives include acid, diatomaceous earth, lime, chlorine,
flushing chemicals for RO membranes, potassium permanganate.
11. RO module life is four years - replacement cost is 28£/gpd capacity.
12. The brine treatment system is of concrete construction with high speed
floating aerators.
13. The product water treatment system utilizes a portion of the sedimen-
tation tank overflow for neutralization and potassium permanganate for
manganese oxidation, followed by filtration and chlorination.
Table 56 shows the major cost items for the treatment system. The
cost estimates were based on vendor quotations or purchase prices at the time
the report'^) was written. Advancement in reverse osmosis technology is
likely to bring about price reductions in RO equipment. Also it must be con-
sidered that two tasks are being performed, i.e. , treatment of acid mine
drainage and production of potable water.
-291-
-------
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TABLE 56
MAJOR COST ITEMS FOR 0.75 MGD
REVERSE OSMOSIS TREATMENT PLANT
1. CAPITAL COSTS
A. Pretreatment
Filtration (diatomaceous earth)
pH Control
Disinfection $ 29, 000
B. RO System
Modules
Pumps and Plumbing
Instrumentation $385,000
C. Brine Treatment System
Aeration Unit (high-speed surface aerator)
Sedimentation Unit
Chemical Feeders and Controls $ 58, 000
D. RQ Product Water Treatment
Iron and Manganese Removal
Final Filtration
Chlorination $31, OOP
Total Capital Cost $503, 000
Amortized @ 6% - 20 years, = 15^/1,000 gallons of
Product Water
II. OPERATING COSTS IN £/l, 000 GALLONS OF PRODUCT WATER
A. Chemical Additives 4.8
B. RO Modules 17.4
C. Power 7.0
D. Maintenance-Materials 2.0
E. Operating Manpower 17.3
Total 48.5
After Rex Chainbelt, Inc., 1972(72)
-293-
-------
Gulf Environmental Systems Company performed studies(^) to evalu-
ate the reverse osmosis process for treating acid mine drainage with high
ferric iron content. They found it possible to attain water recoveries of 80
to 90 percent. Environmental Protection Agency personnel carried out neu-
tralization and decantation operations followed by recycling of the super-
natant through the reverse osmosis unit. This resulted in effective 98 per-
cent water recovery based on feed volume, with maintenance of excellent
quality in the recovered permeate water. This process combining reverse
osmosis and neutralization has been termed "neutrolosis" by Hill, et al.
-294-
-------
SUBMERGED COAL REFUSE COMBUSTION PROCESS
Black, Sivalls and Bryson, Inc. '' ' performed engineering, laboratory
and economic studies on a two-stage coal refuse combustion process for the
treatment of acid mine water. The process utilizes coal refuse as fuel to gen-
erate steam for the conversion of acid mine water to potable water. Energy
for steam generation to operator evaporators for distillation or to drive pumps
for reverse osmosis, is derived from a two-stage coal refuse combustion pro-
cess. In the first stage of combustion, high-sulfur coal refuse or similar
low-cost fuel is dissolved in a molten iron bath. In the second stage of com-
bustion the fuel carbon is burned with air at the surface of the iron bath, gen-
erating hot carbon monoxide which can be further burned to release additional
heat in a boiler.
Two-stage combustion makes it possible to use high sulfur bearing fuels
without polluting the air. Fuel sulfur is trapped in the iron from which it is re-
moved via a lime-bearing slag in the form of calcium sulfide, without generating
sulfur oxides. Sulfur is also recovered from the reduction of the sulfate content
of the acid mine water. Sulfates contained in the sludge generated by distillation
or reverse osmosis units are dried and added to the combustor as part of the
slag. Sulfur is extracted from the calcium sulfide in the slag by treating the
hot slag with steam and air to recover elemental sulfur.
The recovery of sulfur from the acid mine water and the fuel, coupled
with the utilization of coal refuse as a fuel, provides the economic incentive for
treatment of acid mine water using this process.
Figure 61 presents a flow chart of the process. The dotted lines on the
flow chart indicate the acid mine water may or may not be partially neutralized.
Partial neutralization will be required for concentrated acid mine water to pre-
vent excessive corrosion of the flash distillation equipment, but for moderately
concentrated acid mine water the process economics are more attractive without
neutralization. Referring to Figure 61, if neutralization is required, acid mine
water is introduced into a neutralizer (1) where it is contacted with finely divided
limestone to partially neutralize the acid mine water to a pH of 3 or more. The
limestone used for partial neutralization reduces the amount of flux introduced
into the dryer (4) for use in combustor (5). The neutralized water which con-
tains suspended solids is pumped to a flash distillation unit (7) to produce potable
water and a concentrated brine slurry which is subsequently fed to the rotary
kiln dryer (4). If acid mine water is not neutralized, it is fed directly into the
distillation unit.
The rotary kiln dryer serves three functions: 1) to dry the concentrated
brine slurry from the distillation unit, 2) to calcine dolomitic limestone to pro-
duce lime and magnesia for use as flux in the combustor, and 3) to preheat the
portion of the desulfurized spent slag from the desulfurization unit. The con-
tents of the dryer are fed to the combustor (5) to minimize the quantity of dolo-
mitic limestone required in the process.
-295-
-------
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The combustor is a refractory-lined steel vessel that contains molten
iron. Coal or coal refuse is pneumatically injected beneath the surface of the
iron bath where the carbon is dissolved to free its sulfur for ultimate reaction
with the flux floating on the molten iron surface. Air is then injected slightly
below the surface of the bath and reacts with carbon to produce a carbon mon-
oxide rich offgas. Heat generated during the combustion of the coal provides
the necessary heat of reaction to reduce calcium sulfate contained in the dryer
solids to calcium sulfide. In addition, the combustor provides the energy re-
quired to produce iron from iron compounds contained in the dryer solids and
pyrite contained in the coal. Molten elemental iron is continuously removed
from the combustor. Slag containing calcium oxide, magnesium oxide, ash
and calcium sulfide is continuously removed from the combustor and sent to
the slag desulfurization unit (8) where it is contacted with steam and air to
produce a sulfur-rich gas. Elemental sulfur is condensed out of this gas and
sent to storage.
Desulfurized spent slag exiting the desulfurization unit is divided into
two streams which proceed to the dryer, and to a spent slag storage pile.
Spent slag consists of a dry mixture of silica, alumina, magnesium hydroxide
and calcium hydroxide.
Carbon monoxide rich offgas generated in the combustor is used to
supply energy for operation of auxiliary equipment. A large fraction of the
combustor offgas is sent to the waste heat boiler (10) which provides high
pressure steam for the steam turbine-air compressors (15) and the exiting
low pressure steam for the flash distillation unit. Steam generated in the
waste heat boiler undergoes a pressure reduction through the steam-turbine
air compressors before entering the distillation unit. In the study, steam
from the waste heat boiler was assumed to enter the distillation unit directly.
Steam turbine air compressors are used to generate pressurized air for com-
bustion and coal pneumatic conveying. Combustor offgas is also used to pro-
vide the energy requirements for air preheating (13), for drying and calcining
the dryer contents, and drying the incoming coal (14).
Laboratory experimentation was conducted on those areas which could
profoundly affect the process. Engineering studies show that the process has
potential for supplying inexpensive energy for distillation and permits the re-
covery of sulfur so that distilled water is economically produced. Depending
upon the acid mine water composition and a sulfur selling price ($20 to $30/
ton) the break-even price of water for a 5 MGD plant varies between $0.42 and
$0. 16/1, 000 gallons when a 14 percent capital interest charge is used.
Table 57 shows the acid mine water compositions used in the studies
and Table 58 gives an analysis of the coal refuse selected as representative of
a high sulfur coal. Table 59 shows the capital investment needed for various
sizes of treatment plants using the two-stage coal refuse combustion process.
The break-even price or the cost per 1, 000 gallons of product water for a 5
MGD plant is shown in Table 60. Figure 62 indicates that the capital invest-
ment is not a linear function of plant capacity and economies can be realized
-297-
-------
by using higher plant capacities. This infers that the plant should be located
at a large source of acid mine drainage provided coal refuse is located in the
vicinity. All costs are based on mid-1970 prices.
-298-
-------
TABLE 57
ACID MINE DRAINAGE COMPOSITIONS USED IN STUDY
OF TWO -STAGE COAL REFUSE COMBUSTION PROCESS
Moderately
Dilute (ppm) Concentrated (ppm)
Acidity (as ppm CaCOj) 400 1,200
Sulfate 1,061 3,183
Total Iron 200 600
Calcium (as Ca) 80 240
Aluminum (as Al) 5 15
Magnesium (as Mg) 24 72
TABLE 58
ULTIMATE ANALYSIS OF COAL REFUSE
(% By Weight)
Carbon 40.6
Hydrogen 2.9
Oxygen 3. 7
Nitrogen 0.7
Sulfur 10.0
Moisture 3. 0
Ash 39.3
From: Black, Sivalls, & Bryson, Inc.,
-299-
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-300-
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TABLE 60
DETERMINATION OF BREAK-EVEN PRICE OF WATER**
5 MGD ACID MINE DRAINAGE TREATMENT PLANT
USING TWO-STAGE COAL REFUSE COMBUSTION PROCESS
Investment Cost $8,100,000
Potable Water Production 4, 975, 000 GPD
Daily Production Cost
Capital Interest Charge*, (14%) 3, 150
Flux, 1105 Tons @ $2/ton 2,210
Coal Refuse, 1427 Tons @ $0. 25/ton 357
Labor 300
Maintenance, 3% of Investment 675
$ 6,692
Daily Production Credits (not including potable water credit)
Sulfur, 126 tons @ $25/ton $ 3, 150
Iron, 60 tons @ $20/ton 1,200
Slag, 1082 tons @ $. 5/ton 541
$ 4,891
Operating Revenue (not including potable water credit) (1,801)
Break-even Price of Water $1, 801 x 1, OOP = $0. 36/1000
4,975,000 of water
Potable Water Credit $ 1,801
Operating Revenue 0
^Capital Interest Charge = $8, 100, 000 x . 14/360 days
##Assume: 1) Moderately concentrated acid mine drainage, 2) eight (8)
percent sulfur refuse, and 3) a heat rate of 3.25 million BTU
per 1, 000 gallons of acid mine drainage.
-301-
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FIGURE 62
0)
E
tn
o>
>
c
Q.
O
O
I2r
10
* 8
Q
c
o
0
0
2 4 6 8 10
AMW Plant Capacity, Million Gallons per Day
EFFECT OF PLANT CAPACITY ON CAPITAL INVESTMENT
TWO STAGE COAL REFUSE COMBUSTION PROCESS
From: Black, Sivalls, & Bryson, Inc., 1971
(76)
-302-
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FREEZING (CRYSTALLIZATION) PROCESS
Hill, 1968* ' discusses the principles of crystallization treatment and
says crystallization processes have a distinct energy advantage over many
other methods of demineralization because the freezing (heat of fusion) of
water only requires 144 btu per pound of water, or less than one-sixth of the
heat of vaporization. In his opinion, two methods of crystallization appeared
applicable to the treatment of mine drainage, i.e. the freezing method and the
gas hydration method, although, these techniques had not been tested on actual
mine drainage. He points out that the immediate research need in the area of
crystallization is a study to determine if the more troublesome ions found in
mine drainage, such as ferrous iron, ferric iron, sulfate, calcium, aluminum,
magnesium and manganese can be removed efficiently and economically.
Applied Science Laboratories, Inc.'' ') under contract to the Environ-
mental Protection Agency performed a series of over 50 batch experiments in
a study of the freezing process in 1970. In these experiments four-liter quan-
tities of acid mine water were subjected to partial freezing to the extent of up
to 50 percent conversion to ice. After partial freezing, the ice and unfrozen
water (mother liquor) were separated. The ice was melted and these melts
(product water) were found to have a reduction of metal and acid components
of 85 to 90 percent. In experiments in which both ferrous iron and total iron
were determined, the product water had about the same ratio of ferrous iron
to total iron as the original acid mine water, so it appears there is little oxi-
dation of ferrous iron during the partial freezing. Difficulties with analytical
results prevented a firm conclusion as to the reduction of sulfate.
Similar percent reductions of metal ions occurred in freezing experi-
ments using acid mine water that had been treated with lime. Reduction in
hardness of the lime-treated water was nearly 100 percent, but the pH remained
substantially unchanged.
As a result of these experiments, Applied Science Laboratories, Inc.,
proposed a partial freezing process described in Figure 63 consisting of the
following three steps:
1. The mineralized water is refrigerated to convert a considerable fraction
of it into ice.
2. As much as possible of the mother liquor is drained off the ice, almost all
the salts remain in the mother liquor.
3. The ice is melted to produce product water.
Partial freezing as a crystallization process appears to be technically
feasible for treatment of mine drainage, but studies have not advanced beyond
laboratory batch tests. It is yet to be proven that this method would be appli-
cable to mine drainage treatment in large scale studies, i.e. , technically or
economically feasible.
-303-
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FIGURE 63
MOTHER LIQUOR
ACID MINE WATER
(600 p.p.m.total iron)
PARTIAL FREEZING
I
ICE
(wet with mother liquor)
RINSE OR WASH WITH
LIMITED VOLUME OF
PURE WATER
FIRST MELT
PRODUCT WATER
WASHED OR RINSED
ICE
FIRST
PARTIAL MELTING
UNMELTED ICE
WASH WATER
OR
RINSE WATER
SECOND
PARTIAL MELTING
SECOND MELT
PRODUCT WATER
UNMELTED ICE
THIRD MELT
PRODUCT WATER
COMBINED PRODUCT WATER
(60 p.p.m. total iron)
FLOW DIAGRAM FOR PARTIAL FREEZING
OF ACID MINE WATER
From: Applied Science Laboratories, Inc., 1971
(77)
-304-
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The Office of Saline Water has been studying the separation of salts
from water by crystallization for a number of years, but these studies are
concerned with treatment of brackish water and not mine drainage. Several
pilot plants are in operation. Schroeder, et al.V'"), in 1966 wrote a report
for the Office of Saline Water in which they analyzed the application of saline
water conversion processes to acid mine waters. They estimated the cost
of treating mine drainage from Kittanning Run, Pennsylvania by vacuum
freezing, secondary refrigerants (N-Butane) and the hydrate process. These
costs for plant investment and operation are calculations only, based on the
assumption that the desalinization data are applicable to acid mine drainage.
The capital and operating costs are presented in Table 61 and they have not
been updated since it is felt that updating these costs would serve no purpose.
-305-
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TABLE 61
SUMMARY OF CRYSTALLIZATION COSTS
USING KIT TANNING RUN, PENNSYLVANIA,
WATER AS FEED
Capital Costs
Plant Capacity
(millions of
gal. /day)
0.1
1.0
10
100
Production
(millions of
gal. /day)
0. 1
1.0
10
100
Direct
Freezing
$ 434,900
2,219,000
12,945, 000
81,608,000
Operating
(dollars per 1,
Direct
Freezing
3.10
1.32
0.85
0.68
Secondary
Refrigerant
$ 456,800
2, 198,000
11, 970, 000
70, 362, 000
Costs
000 gallons)
Secondary
Refrigerant
3.18
1.34
0.85
0.67
Hydrate
Process
$ 465,900
2,273, 000
12, 572, 000
74, 940, 000
Hydrate
Process
3.23
1.38
0.89
0.71
Note: (1) Plants operate at a load factor of unity
(2) Product water is about 400-500 mg/1 total dissolved solids
After Schroeder, et al. , 1966(70)
-306-
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ELECTRODIALYSIS PROCESS
Considerable work has been accomplished by the Office of Saline Water
in using electrodialysis for production of fresh water from brackish water.
The electrodialysis process, like the reverse osmosis process, utilizes mem-
branes, however, electricity is the driving force in electrodialysis.
An electrodialysis unit would consist of a number of narrow compart-
ments separated by closely spaced membranes. Each compartment is bound
by a cation and an anion membrane which are permeable to positive and nega-
tive ions respectively. A positive electrode is located at one end of this "stack"
and a negative electrode is located at the other end. The intermediate channels
between each pair of membranes is filled with the solution to be processed.
When the electrodes are energized, thereby causing an electric current to pass
through the solution and the stack of membranes, the ions contained in solution
migrate through the various channels. Cations migrate through the cation mem-
branes and anions through the anion membranes. Considering a group of three
channels separated by two membranes (one anion permeable and one cation per-
meable), it can be seen that the cations and anions migrate from the center
channel through the respective membranes enclosing the channel reducing the
concentration of salts in this center compartment. Since the entire stack of
membranes consists of alternate anion and cation elements, a succession of
fresh water and brine channels is found to exist' '.
The principle energy requirement of the electrodialysis process is elec-
trical energy to the electrodes in the stack. Energy is also used for pumping
the feedwater through the system. The total electric energy required is a func-
tion of the salt reduction which must be accomplished in producing fresh water.
An electrodialysis plant for treatment of acid mine drainage would consist of
1) a coagulation-filtration pretreatment processing unit to reduce iron, mangan-
ese, and suspended solids concentrations and to adjust pH, 2) a circulating pump,
3) electrodialysis unit, 4) product water recovery and storage system, and 5)
provisions for brine
Bench scale studies of electrodialysis for mine drainage treatment were
performed by the Environmental Protection Agency at Norton, West Virginia, in
cooperation with the Office of Saline Water^ '. When used on water receiving
no pretreatment, the cathode cell quickly became fouled with iron. In those
cases where the mine drainage was pretreated by lime neutralization for iron
removal, the unit operated satisfactorily.
Schroeder, et al. ' calculated capital and operating costs for various
size treatment plants in their 1966 analysis of the application of saline water
conversion processes to acid mine drainage treatment. It should be pointed out
that these costs are assumptions based on the application of a process effective
in saline water conversion, but not tested for acid mine drainage treatment.
Table 62 presents these capital and operating costs which are not updated for
this study.
-307-
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TABLE 62
ELECTRODIALYSIS TREATMENT PLANT
USING KIT TANNING RUN, PENNSYLVANIA
WATER AS FEED
Plant Capacity
(Millions of
Gal. /Day)
0. 1
1.0
10.
100.
Capital
Cost
$ 249, 000
1, 309, 000
8, 760,000
65,709,000
Operating Costs
($/l, 000 Gallons)
2.52
1.01
0.68
0.58
Note: 1) Plants operate at a load factor of unity.
2) Product water is about 400-500 mg/1 total dissolved solids.
After Schroeder, et al. , 1966(70)
-308-
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FOAM SEPARATION (FRACTIONATION) PROCESS
Foam separation (fractionation) is based on the phenomenon of surface
activity which results from the ability of certain solutes (surfactants) to re-
duce the surface free energy of their solutions, and therefore the total free
energy of the system, by accumulating at an interface. Surface activity as it
relates to foam separation process is described using the concept of Gibbs
surface excess^'''.
In practice, foam separation consists of passing bubbles through a solu-
tion of surface active solute(s) with the aim to adsorb the solute(s) onto the gas -
liquid interfaces and to remove these surfaces intact as foam, thus effecting a
separation. Further, by coadsorption of non-surface active with surface active
solutes, the former can be separated from solution with the latter. This is the
case in the treatment of acid mine drainage''"I
Horizons Incorporated^"^), conducted laboratory studies of continuous
flow foam separation to determine the optimum operating conditions of maxi-
mum extraction of dissolved metal cations (Fe, Ca, Mg, Mn and Al) from acid
mine drainage. Continuous flow foaming experiments were conducted in a 6 inch
diameter glass column capable of liquid flow rates of 3 to 12 gallons per hour.
The approach to foam separation taken was the production of persistent foams
which allowed protracted foam drainage to reduce liquid carry-over in the foam.
The effects of pH, chelate addition, surfactant type and concentration, air sparg-
ing rate, metal concentration and foam drainage were investigated in relation to
metal extraction.
The low extraction capacity of foam separation (fractionation) makes the
process unattractive for the treatment of acid mine drainage.
-309-
-------
NEUTRADESULFATING PROCESS
This process essentially involves 1) neutralization of mine drainage
feed and precipitation of iron and aluminum using soda ash or sodium bicar-
bonate as the neutralizing agent and 2) treatment of the effluent which is now
free from iron and aluminum by an ion exchange system to remove sulfate.
The resin is loaded in the barium form, and the barium sulfate precipitate is
removed. Catalytic, Incorporated^*) conducted laboratory studies on acid
mine drainage and developed the conceptual neutradesulfating process shown
in Figure 64.
The advantages claimed for the process are:
1. A substantial reduction in the concentration of major pollutants in the
acid mine water. Virtually a complete removal of iron and aluminum
and a large reduction in sulfate content.
2. Sludge disposal is at a minimum.
3. Operating costs for labor are low.
4. Almost all of the chemicals produced are reused in the process.
5. Production of a high-purity water.
However, as reported by Catalytic, Inc. , based on the projected or
scaled up technology, the treatment cost for a 1 MGD plant would be $2.69/
1, 000 gallons of treated water based on a 30 year payback period at 4, 6%.
The total capital investment was estimated at 4.96 million dollars and rep-
resents about 35% of the unit cost or $0.94/1, 000 gallons.
Because of the high projected cost of acid mine drainage treatment by
this method, the project was terminated.
-310-
-------
1
f^
5
1
^ r\ ^
O ^> ifi
05 —
c ^ ^
-311-
-------
REFERENCES
1. Hill, Ronald D. , 1968, Mine Drainage Treatment - State of the Art and
Research Needs: Fed. Water Pollut. Coiitr. Adm. , Mine Drainage
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-------
13. Davis, D. W. , Brown, T. S. and Long, B. W. , 1972, De water ing
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17. Wakeman, S. A. and Joffe, J. S. , 1922, Microorganisms Concerned
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-313-
-------
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-314-
-------
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-315-
-------
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-316-
-------
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(No BCR No. )
62. ZabbanW., Fithian T. and Maneval, D. R., 1972, The Coal Mine
Drainage Problem - Conversion to Potable Water by Ion Exchange:
Am. Water Works Ass. Ann. Conf. , Chicago, 31 p. , 3 fig. (BCR 72-
63. Bowen, D.H.M. (Managing Ed. ), 1971, Ion Exchangers Sweeten Acid
Water: Environ. Sci. Technol. _5 (1), p. 24-5 (BCR 71-1)
64. Holmes, Jim and Schmidt, Ken, 1972, Ion Exchange Treatment of Acid
Mine Drainage: Fourth Sym. Coal Mine Drainage Res. Preprints,
Pittsburgh, p. 179-200 (BCR 72-
65. Rex Chainbelt, Inc., 1970, Treatment of Acid Mine Drainage by Reverse
Osmosis: Fed. Water Quality Adm. , Res. Ser. 14010 DYK 03/70, 35 p.
(BCR 70-53)
66. Golomb, A. and Besik, F. , 1970, Reverse Osmosis for Wastewater
Treatment: Ind. Water Eng. ( ), p. 16-19, (No BCR NoT)
67. Reidinger, A. B., and Schultz J. , 1966, Acid Mine Water Reverse
Osmosis Tests at Kittanning, Pennsylvania, Final Report: Office Saline
Water, Rept. GA-7019 (No BCR No.)
68. Kreman, S. S. , Nusbaum, Isadore, Riedinger, A. B. , 1970, The Rec-
lamation of Acid Mine Water by Reverse Osmosis: Third Sym. Coal
Mine Drainage Res. Preprints, Pittsburgh, p. 241-66 (BCR 70-21)
69. Keilin, B., 1966, The Fundamentals of Reverse Osmosis: Proc. Sym.
Membrane Processes for Ind. (No BCR No.)
70. Schroeder, W. C., et al. , 1966, Study and Analysis of the Application
of Saline Water Conversion Processes to Acid Mine Waters: Office
Saline Water, Progr. Rept. No. 199, 65 p. (BCR 66-101)
71. Mason, D. G. , 1970, Treatment of Acid Mine Drainage by Reverse Os-
mosis : Third Sym. Coal Mine Drainage Res. Preprints, Pittsburgh,
p. 227-40 (BCR 70-20)
72. Rex Chainbelt, Inc. , 1972, Reverse Osmosis Demineralization of Acid
Mine Drainage: Environmental Protection Agency, Water Quality Office,
Res. Ser. 14010 FQR 03/72, 109 p. (BCR 72-
-317-
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73. Wilmoth, R. C. , Mason, D. G. , and Gupta, M. , 1972, Treatment of
Ferrous Iron Acid Mine Drainage by Reverse Osmosis: Fourth Sym.
Coal Mine Drainage Res. Preprints, Pittsburgh, p. 115-56 (BCR 72-
74. Gulf Environmental Systems Co., 1971, Acid Mine Waste Treatment
Using Reverse Osmosis: Environmental Protection Agency, Water
Quality Office, Res. Ser. 14010 DYG 08/71, 84 p. (BCR 71-34)
75. Hill, R. D., Wilmoth, R. C. and Scott, R. B., 1971, Neutrolosis Treat-
ment of Acid Mine Drainage: 26th Ann. Purdue Ind. Waste Conf. ,
Lafayette, Ind., 13 p. (BCR 71-17)
76. Black, Sivalls & Bryson, Inc., 1971, Evaluation of a New Acid Mine
Drainage Treatment Process: Environmental Protection Agency, Water
Quality Office, Res. Ser. 14010 DYI 02/71, 155 p. (BCR 71-25)
77. Applied Science Laboratories, Inc., 1971, Purification of Mine Water
by Freezing: Environmental Protection Agency, Water Quality Office,
Res. Ser. 14010 DRZ 02/71, 61 p. (BCR 71-4)
78. Powell, J. H. and Vicklund, H. I., 1968, Preliminary Evaluation of the
Electrodialysis Process for Treatment of Acid Mine Drainage Waters:
Final Report to Office of Saline Water, Contract 14-01-0001-1187, un-
published, April, 1968 (No BCR No.)
79. Hanson, Peter J. , 1972, Foam Separation of Metals from Acid Mine
Drainage: Fourth Sym. Coal Mine Drainage Res. Preprints, Pittsburgh,
p. 157-78 (BCR 72-
80. Horizons, Inc., 1971, Foam Separation of Acid Mine Drainage: Environ-
mental Protection Agency, Water Quality Office, Res. Ser. 14010 FUI
10/71, 55 p. (BCR 71-
81. Catalytic, Inc., 1971, Neutradesulfating Treatment Process for Acid
Mine Drainage: Environmental Protection Agency, Water Quality Office,
Res. Ser. 14010 DYH 12/71. 102 p. (BCR 71-
82. O'Melia, C. R. and Stumm, W. , 1967, Aggregation of Silicon Dispersion
by Iron (III): Jour. Colloid and Interface Sci. , 23 ( ), p.
No BCR No. )
83. Singer, P. C. and Stumm, W. , 1968, Kinetics of the Oxidation of Ferrous
Iron: Second Symposium Coal Mine Drainage Res. Preprints, Pittsburgh,
p. 12-34 (BCR 68-2)
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OTHER MINE DRAINAGE ABATEMENT PROCEDURES
Table of Contents
Page No.
Limestone Barriers Across Streams 321
Insitu Precipitation of Ferric Hydroxide 323
Spoil Pile Neutralization 323
Deep Mine Water Diversion 324
Insitu Neutralization of Acid Mine Water by Injecting Fly Ash
into Deep Mines 325
References 327
-319-
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OTHER MINE DRAINAGE ABATEMENT PROCEDURES
Limestone Barriers Across Streams
It has long been known that acid mine waters flowing through a lime-
stone terrain become neutralized. The construction of limestone barriers
across streams is an attempt to create similar environmental conditions in
alkaline poor stream basins.
This method of stream neutralization was tried on Sandy Run in Vin-
ton County, Ohio in the early 1950's^). Sandy Run is an acid stream feeding
Lake Hops, a center for extensive water-oriented recreation. A low dam was
constructed across Sandy Run and the upstream side of the structure filled with
granular limestone. The path of natural stream flow was directed through the
limestone bed. The limestone was initially effective in raising the pH of the
water, but in less than one month, a heavy rain and resulting high stream flow
largely covered the limestone bed with sand and reduced its effectiveness.
The sedimentation problem grew progressively worse so that within six months,
it was necessary to move the limestone from behind the dam to the stream bed
below the structure. Again, an initial improvement in water quality was noted
at normal stream flow rates. As before, this improvement gradually dimin-
ished as sediment accumulated in the voids of the limestone bed. The project
was abandoned.
Recently, under Operation Scarlift Project SL 121, a series of six
limestone barriers were constructed across Trough Creek in Huntingdon County,
Pennsylvania. The project was designed by Africa Engineering Associates, Inc.
for the Pennsylvania Department of Environmental Resources and the cost of
construction was funded by a grant from the U. S. Environmental Protection
Agency(2).
The barriers were constructed of coarse limestone aggregate having a
high calcium-low magnesium carbonate composition. The aggregate is held in
place by a blanket of heavy stone riprap on the upstream and downstream sides
of the limestone barrier. Riprap was also placed along the stream banks for
erosion control. The total cost of construction was $191,270.00 and engineering
design costs were $22, 198.00, Contract items and costs are as follows:
-321-
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Unit
Item Quantity Unit Price Cost
Site Clearing Job L.S. --- $ 15,000.00
Excavation and Disposal 9,306 C.Y. $ 2.40 $ 22,334.40
Rolled Embankment 1,109 C.Y. $ 1.80 $ 1,996.20
Furnishing and Placing
Riprap Creek Bank Linings 552 S.Y. $12.00 $ 6,624.00
Furnishing and Placing
Grouted Stone Riprap 798 S.Y. $18.00 $ 14,364.00
Furnishing and Placing
Concrete Masonry 153 C.Y. $80.00 $ 12,280.00
Furnishing and Placing
Rock Fills 1,552 C.Y. $12.00 $ 18,624.00
Furnishing and Placing
Limestone Media 3,336 C.Y. $24.00 $ 80,064.00
Other Misc. Items --- --- --- $ 19,983.40
Total Cost $191,270.00
The average cost for a limestone barrier on this project was $31, 878. 33.
The limestone barriers are still undergoing evaluation for their effectiveness in
neutralizing the acid flow. It appears remedial construction will be necessary
because of erosion and siltation of the barriers and it is possible this problem
may occur annually.
Major factors affecting costs on projects of this nature are:
1. Accessibility of project area.
2. Time of construction.
3. Complexity of design.
4. Availability of riprap materials.
5. Haulage distance of suitable crushed limestone.
6. Nature of stream bottom.
7. Frequency and magnitude of stream flooding.
8. Stream water quality.
9. Degree of neutralization desired.
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Insitu Precipitation of Ferric Hydroxide
Laboratory studies performed by the Parsons-Jurden Corporation^)
indicated insitu neutralization of mine water with the resulting precipitation
of sludge would be effective in mine sealing. Water slurries of alkaline re-
actants such as limestone or fly ash if injected directly into the water in a
mine would form a sludge. The sludge formed should eventually fill the mine
and effectively seal it. The advantage of filling with sludge, is that sludge is
a balking type precipitate, taking up more volume than that occupied by the
unreacted material used to treat the mine water.
In 1968 the Parsons-Jurden Corporation received a contract from the
Pennsylvania Department of Mines and Mineral Industries, now the Department
of Environmental Resources, for mine sealing by insitu precipitation of ferric
hydroxide. The actual work performed consisted of the construction of rubble
barriers within three mine headings of the inactive Driscoll No. 4 mine near
Vintondale, Pennsylvania. The barriers were constructed of available mat-
erials from within the mine and injection pipes extended through the barriers
to the interior of the mine. A lime slurry was injected into the mine to neu-
tralize the mine water and precipitate iron hydroxide. Clogging of the rubble
barriers with iron hydroxide did not occur and the project was abandoned.
The mine drainage effluent was alkaline during pumping operations,
but whenever the injection of lime slurry was stopped the effluent became
acidic. The reasons for the failure of sludge to form have not been docu-
mented, but it appears the alkaline effluent did not precipitate iron hydrox-
ide until after it left the mine. Cost figures are not available, but it is esti-
mated the total project cost exceeded $Z50, 000.
Spoil Pile Neutralization
Spoil pile neutralization by drilling and grouting a pulverized limestone -
lime slurry has recently been completed near Toms Run in Clarion County,
Pennsylvania. This work was performed for the Pennsylvania Department of
Environmental Resources under Operation Scarlift Project SL 165(4).
If mine refuse is grouted with powdered limestone and lime, an alkaline
reserve should be available for neutralization of the acid salts produced by
pyrite oxidation. In addition to this effect, pyrite may become sealed from the
air when surrounded by the grout slurry. A third mechanism may also operate
to reduce the amount of pyrite undergoing chemical reaction; the sudden change
in pH of the spoil material may decrease the activity of iron oxidizing bacteria.
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The costs for this project are as follows:
Unit
Description Price Quantity Cost
1. Slurry Injection Holes $ 1.00/Each 453. $ 453.00
2. Driving Grout Sleeves 0.50/L. F. 9,778. 4,889.00
3. Pulverized Limestone 11.45/L.F. 5,234.4 59,933.88
4. Hydrated Lime 35.00/L.F. 504.13 17,644.55
5. Flume Drains 3.25/L.F. 1,400. 4, 550. 00
Total Cost $87,407.43
Pollution abatement using this method would have the advantage of pro-
ducing immediate and significant results. There is some doubt, however, as
to the lasting effect of this type treatment.
The main factors affecting costs of spoil pile neutralization are:
1. Accessibility of the project area.
2. Unit Costs of materials.
3. Haulage distance for materials.
4. Number of drill holes required.
5. Degree of abatement desired.
Deep Mine Water Diversion
Mine water diversion work is in progress at the Ernest Mine Complex,
Operation Scarlift Project No. SL 107-4, in Indiana County, Pennsylvania^).
The purpose of the project is to divert mine drainage flows from various lo-
cations in the mine to a central point where a water treatment plant will be
constructed in the future.
In order to achieve this goal, it is necessary in several areas of the ex-
tensive mine workings to impound water to a design elevation so that mine waters
can flow over drainage divides or humps within the mine to the central treatment
location. The necessary work includes sealing of numerous shafts, drifts and
boreholes, the placement of an 18 inch mine water transfer pipe within the mine,
removal of a mine barrier, installation of permanent valves and concrete struc-
tures as well as other items.
The original contract estimate for this diversion work was $266, 815,
however, a total of five change orders to date have increased the total estimated
cost to $333,790 and additional change orders may be necessary. Some reasons
for the additional cost are as follows and they provide an insight into the types of
problems that can be expected in deep mine water diversion:
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1. Additional boreholes were discovered during exploratory shaft excavation
and they required sealing.
2. Dewatering of some areas was not practical and the 18 inch transfer pipe
had to be installed under water in these areas.
3. Two mine dams were found to be unsatisfactory and additional work was
required.
4. A subsidence cave-in developed during construction which required re-
moval of material and support to prevent a total collapse which would
have damaged the 18 inch transfer pipe.
5. The sealing of some parts of the mine created hydraulic heads which
caused boreholes and nearby water wells to develop artesian flow. These
boreholes and water wells will have to be sealed.
6. Some contract items, such as calipering and reaming of boreholes, appear
to be unnecessary and may have added to the project cost.
Insitu Neutralization of Acid Mine Water by Injecting Fly Ash into Deep Mines
The Duquesne Light Company is sluicing alkaline fly ash from the Col-
fax power station into an abandoned section of the Harwick Mine. The mine
and power station, both owned by Duquesne Light Company, are about 14 miles
northeast of Pittsburgh. The idea of this unique system was conceived, in part
at least, because of space limitations for fly ash disposal at the adjacent site
for the new Cheswick plant under construction. The Harwick Mine will be com-
pletely worked out about the time the new power station goes into service.
The engineering study for Cheswick plant indicated there were distinct
economic advantages in disposing of fly ash into the Harwick Mine. Cost of
removal of fly ash to a landfill area is 80 - 90^/ton. Capital investment pro-
posals for conventional ash disposal varied from $500, 000 to over $1, 000, 000
and annual operation and maintenance cost was estimated at $Z50, 000.
Cost estimates for the proposed fly ash disposal system, including mine
modifications, pumps, an electrical substation and the necessary controls, were
less than the amounts for conventional fly ash disposal methods. Savings for the
new Cheswick plant are estimated at $700/day, after allowances for mine de-
watering costs.
In addition to treatment of acid mine water, deep mine disposal of fly
ash has the distinct added advantage of eliminating completely the air pollution
problems associated with landfill disposal.
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The disposal system using both fly ash and bottom ash from the Colfax
plant has operated for 18 months, with only minor problems (as of December,
1968). The ash is pumped as a slurry through a borehole into the mine. Dams
have been constructed in the mine to form a large sedimentation basin to settle
the fly ash out of the mine water.
The water quality characteristics of the effluent have been well within
the quality limits prescribed by the Pennsylvania Sanitary Water Board. The
amount of water pumped from the ash disposal basin has averaged over 2
million gallons/day. In the 18 months the ash disposal system has been in
operation, the suspended particulate content of the effluent has never approached
the permissible maximum of 200 mg/1; the highest observed value was 97 mg/1.
Average values for water quality characteristics are: pH - 7.2, Fe -2.5 mg/1
and suspended solids - 9.4 mg/1.
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REFERENCES
1. Stanley Consultants, 1969, Lake Hope Acid Mine Drainage Abatement
Program: Rept. to Ohio Dept. Natural Resources, 38 p. (BCR 69-31)
2. Pennsylvania Department of Environmental Resources, 1972, Informa-
tion in Files: Ebensburg District Office
3. Jones, J. B. and Ruggeri, S. , 1969, Abatement of Pollution from Aban-
doned Coal Mines by Means of In-Situ Precipitation Techniques: ACS
Div. Fuel Chem. Preprints _13_ (2), p. 116-19 (BCR 69-14)
4. Molinski, A. E. , 1972, Personal Communication: Ebensburg District
Office, Pa. Dept. of Environmental Resources
5. Love, L. R. and Whirl, S. F. , 1969, Fly Ash Disposal in a Deep Mine:
Coal Mining and Processing 6_ (3), p. 50-53 (BCR 69-99)
-327-
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REFUSE BANK AND MINE FIRES
TABLE OF CONTENTS
Page No.
Introduction 331
National Surveys of Burning Refuse Banks 331
Ignition of Refuse Banks 332
Methods of Controlling and Extinguishing Fires 332
Prevention of Coal Refuse Bank Fires 333
Prevention of Deep Mine Fires and Explosions 334
Cost Figures for Refuse Bank and Mine Fire Projects 335
References 342
LIST OF TABLES
1. Appalachian Mine Fire Control Projects 336
2. Refuse Bank and Stripping Fires 342
-329-
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_REFUSE BANK AND MINE FIRES
Introduction
Our present day environmentally oriented society is constantly on the
alert for new ways and means to combat all forms of pollution. In the Appa-
lachian region, a recurring and everpresent source of pollution has been the
sulfur-emitting, smoldering coal waste banks and deep mine fires. The popu-
lation has been able, only in recent years, to make their voices heard regard-
ing the detrimental effects of these fires and urge that measures be taken to
eliminate this source of pollution.
The deep mine fires are usually extinguished or brought under control
in a relatively short period of time, only if they associated with actively pro-
ducing coal properties, fires in abandoned mines have been allowed to burn
unattended, but not unnoticed for decades.
Coal refuse or waste banks have never seemed to warrant the attention
of the deep mine fires, even though they are a public nuisance and an environ-
mental hazard.
Over the many years these fires have existed, sporadic attempts have
been made by coal companies, municipal and other governmental bodies to
control them. It was not until the establishment of the Appalachian Regional
Commission which was created by the Appalachian Regional Development Act
of 1965 that sufficient funds were made available to put forth a concentrated
effort to combat refuse bank and mine fires. This effort is not only helping
to reduce pollution, but is protecting a valuable national resource.
National Surveys of Burning Refuse Banks
In 1963, the U.S. Bureau of Mines, through a cooperative agreement
with the Public Health Service, Department of Health, Education and Welfare,
conducted the first nationwide reconnaissance survey of burning coal refuse
banks. This survey noted 495 burning coal refuse banks in the United States^ ' '.
Another survey conducted in late 1968 and early 1969 noted 292 burning
coal refuse banks in 13 of the 26 coal-producing states. This total includes only
refuse banks that were determined to be smoldering or buring through visual
indications such as flames or "fire glow, " thermal waves above the refuse bank,
smoke, fumes, or a combination of these conditions. Seven states in the Appala-
chian region accounted for 264 burning banks, or 90 percent of the total. States
that had reported burning refuse banks in the past, but in which none were known
to be burning in 1969, include Alaska, Indiana, Iowa, New Mexico, Tennessee
and Wyoming(2).
-331-
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Coal refuse fires have proven to be extremely hazardous to the environ-
ment and its inhabitants. At least 55 persons have lost their lives as a result
of burning banks. The health and safety of nearby residents, particularly child-
ren and elderly persons, is threatened as a result of the impairment of air
quality caused by the airborne pollution generated by burning waste banks. Veg-
etation and building materials are also severely damaged or destroyed when the
gases are heavily concentrated in an area nearby these sulfur-emitting banks' '.
Ignition of Refuse Banks
Ignition of a refuse bank can be initiated in several ways. A recent
U.S. Bureau of Mines report outlines the following possible sources of com-
bustion (Maneval'l));
1. Spontaneous ignition
a. Sufficient air must enter the refuse dump to oxidize the coal and
other combustible materials.
b. Air must be insufficient in quantity to carry away the heat generated
during the oxidation, thus permitting the heat to accumulate.
2. Careless burning of trash on or near the bank.
3. Forest fires
4. Camp fires left burning
5. Intentional ignition to create residue which may be used for road base
materials.
Spontaneous combustion is a common cause of coal refuse fires. Sixty-
six (66) percent of the 292 refuse banks found burning in 1968 are believed to
have started by heat generated within the pile. This phenomenon results from
the flow of air through combustible refuse material and consequent oxidation.
When sufficient oxidation occurs, heat is generated, and the combustible com-
ponents in the pile ignite' '.
Methods of Controlling and Extinguishing Fires
Federal and State governments have undertaken research projects to
control and extinguish coal waste bank and deep mine fires. Various techniques
have been tried, some of which are listed as follows:
-332-
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Coal Refuse Bank FiresH)
1. Accelerated Combustion and Quenching
2. Isolation
3. Foam Covering
4. Vermiculite and Sodium Bicarbonate Injection and Coating
5. Injection of Fine Mineral Matter
6. Mine Drainage Sludge Injection
7. The Use of Anti-Oxidants
8. Saturation Through Serpentine Canals
9. Ponding Technique (Rice Paddy)
10. Cooling and Dilution
11. Blanketing with Clay and Cement Waste
12. Blanketing - Quarry Wastes
13. Use of Explosives Followed by Quenching
14. Hydraulic Jets (Water Cannon Technique)
15. Water Sprays
Deep Mine Fires
1. Dry Fly Ash Injection with Surface Seals
2. Isolation Plug Barrier and Surface Seal
3. Fly Ash Injection (Wet and Dry)
4. Sand Flushing (including sand barriers)
5. Trenching and Sand Barrier
6. Underground Dam with Water Flooding
7. Smothering with Isolation Seal
Prevention of Coal Refuse Bank Fires
discusses the problems associated with coal refuse disposal
and indicates refuse bank fires can be prevented if more attention is directed
toward: 1) Site selection and preparation, 2) Refuse bank design, and 3) Site
reclamation and abandonment. The following factors and requirements are
important when considering these items of refuse disposal planning:
1 . Site Selection and Preparation
a. Terrain suitable for intended type and quantity of refuse disposal
b. Geologic investigation of site
c. Evaluation of drainage in area
d. Source of non-combustible material nearby
e. Clearing of all combustible material from the site
f. Adequately seal off all coal outcroppings
2. Refuse Bank Design
a. Slope of terrain and foundation materials
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b. Site drainage
c. Compaction methods (soil mechanics principles employed)
d. Control of material segregation, sizing and grading
e. Outside slope sealing
3. Site Reclamation and Abandonment
a. Bank properly graded, compacted and sealed
b. Final layer of non-combustible material placed over bank
c. Establish vegetative cover
d. Fencing and signing
e. Periodic inspection or regular patrols
Prevention of Deep Mine Fires and Explosions(3)
«
The down-time of a mine as a result of a fire or explosion can be long
and the cost of recovery and reconditioning can be extremely high. Some com-
panies have been forced into bankruptcy as a result of such disasters. Every
individual working in a coal mine should be educated as to the cause and pre-
ventative measures designed to prevent disasters. They must see that the
measures are adequate, are maintained, and are enforced.
With the advent of mine mechanization, changes in mining methods and
transportation have been revolutionary and the use of electricity has multiplied
many times. Electric power sources must be effectively controlled at all times,
because a mine environment is not favorably suited to electrical installations -
saturated atmospheres, dust, in suspension, roof falls, poor lighting, restricted
areas, constant jarring of unit-mounted sensitive control or detecting equip-
ment, shock waves from blasting, abrasive use and makeshift repairs, all of
which complicate the electrical, operational and maintenance problems.
Deep mine fires may be initiated in may ways, the following is a list of
possible causes of ignition:
1. Rock falls knocking down bare electrical conductors.
2. Faulty tracks and rolling stock triggering energized trolley wires into
igniting dust or other combustiles as the result of wrecks.
3. Arcs and sparks from trolley skids or wheels.
4. Overloaded power cables and conductors.
5. Failure to properly maintain permissible electrical equipment.
6. Conveyor belt fires, often due to stuck rollers.
7. Sparks from continuous mining machines cutting through pyrite inclusions.
8. Mishandling of explosives used for production blasting.
9. Smoking or open lights in gassy mines.
10. Welding operations not properly conducted.
11. Spontaneous combustion due to poor housekeeping and inadequate ventilation.
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The majority of the above causes can be eliminated through compliance
with the existing Federal and State mining laws, in addition to a company or
mine owner following a regular strict inspection and maintenance program per-
formed by reliable and capable personnel.
Cost Figures for Refuse Bank and Mine Fire Projects
Since the majority of the efforts directed toward the extinguishment and
control of refuse bank and deep mine fires has taken place in the Pennsylvania
anthracite and bituminous coal regions, the cost figures for bank and mine fire
abatement projects presented in this section are from Pennsylvania projects.
Table 1 is a compilation of information on nine (9) mine fire extinguish-
ment projects performed in the bituminous region of Pennsylvania. The un-
published data obtained from the U.S. Bureau of MinesV'*) presents information
on project and unit costs, and the method of extinguishing the fire is indicated.
Data on nine (9) refuse bank and stripping fires was obtained from the
Pennsylvania Department of Environmental Resources'^' ") for the anthracite
region of Pennsylvania. This information is presented in Table 2 and includes
project and unit costs, method of extinguishment and other pertinent data.
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TABLE 1
APPALACHIAN MINE FIRE CONTROL PROJECTS*4)
(U.S. Bureau of Mines - Pittsburgh, Pennsylvania)
Pennsylvania - Bituminous
PROJECT NO. 9 January, 1972
Upper Whyel, Sewickley Township, Westmoreland County, Pennsylvania
Method: Dry Fly Ash Injection - Surface Seal - Emergency Drainage -
Erosion Prevention
(Contractor - Dragan & Son)
Unit Cost
$ 21.00/hr.
3. 15/ft.
2.00/ton
21.50/hr.
23.90/ton
100.00/ton
1.00/lb.
1.00/bale
Project Costs
Remove Vegetation
Angle Dozer 2,082 hrs.
Vertical Boreholes 1, 142 ft.
Loading, Transporting and 29.09 tons
Discharging Fly Ash
Dragline 408-1/2 hrs,
Agricultural Limestone 20.45 tons
10-6-4 Fertilizer 5 tons
Grass Seed 500 Ibs.
Hay or Straw 700 bales
16 Percent (Supervision-Administration-
Engineering)
$ 5, 000.00
43,722.00
3, 597. 30
58. 18
8,782.75
409.00
500.00
500.00
700.00
$63, 269.23
10,123^08
$73,392.31
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TABLE 1 (continued)
PROJECT NO. 10 September, 1970
Carpentertown, Mt. Pleasant Township, Westmoreland County,
Pennsylvania
Method: Backfilling and Erosion Prevention
(Contractor: Yelinek & Smail, Inc. )
Unit Cost Project Costs
$13.75/hr.
5.00/hr.
7. 00/ton
70. 00/ton
40.00/100#
unit
0.75/bale
Angle Dozer
Laborer
Limestone
Fertilizer
Grass Seed
Hay or Straw
16 Percent/Administration &
806 hrs.
16 hrs.
16 tons
4 tons
4 100# units
300 bjales
Engineering
$10,276.50
80,00
113.00
280. 00
160.00
225,00
$11, 133. 50
1, 781.36
$12,914.06
PROJECT NO. 11 August, 1968
Lloydsville, Unity Township, Westmoreland County, Pennsylvania
Method - Dry Ash Injection Method
(Contractor - Dragan & Son)
Unit Cost Project Costs
$ 1.25/ft. Drilling Boreholes 6,449ft, $ 8,061.25
20.00/ft. Casings 123ft. 2,460,00
2.80/ton Fly Ash 6,237. 54 tons 17,465. 12
Total Cost Including Labor, Fertilizer,
Seed, Lime, etc.
(Including 16 Percent for Administration) $ 5, 234. 16
$38,600.13
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TABLE 1 (continued)
PROJECT NO. 17 December, 1970
Near Pennsylvania Turnpike - Plum and Monroeville Boroughs,
Allegheny County, Pennsylvania
Method: Fly Ash Injection and Revegetation
(Contractor: Dragan & Son)
Unit Cost
$ 3.70/ft.
20.00/unit
25.00/unit
1.50/ton
5. 00/ton
10. 00/ton
50.00/100#
unit
Drilling
Casing with Caps
Holes)
Casing Adapters
Fly Ash
Top Soil
Limestone
Grass Seed
Laborers
Project Costs
3, 546 ft.
(Inject.
31 units
1 unit
78. 33 tons
70 tons
1/5 ton
1-100# unit
220 hrs.
$13, 120. 20
620.00
25. 00
117.50
350.00
2.00
50. 00
1, 100. 00
$15,384.70
24 Percent Allowance for Administration
and Engineering 3, 692. 33
$19,077.03
PROJECT NO. 18 March, 1970
Peters Creek, Jefferson Borough, Allegheny County, Pennsylvania
Method: Surface Seal and Isolation Plug Barrier
(Contractor: Dragan & Son)
Unit Cost Project Costs
$ 4.00/hr. Laborer 748 hrs. $ 2,992.00
9. 00/hr. Dragline 256 hrs. 2,304.00
16. 00/hr. Straight Blade Dozer 1,068 hrs. 17,088.00
17.00/hr. Angle Blade Dozer 2, 583 hrs. 43,911.00
2.00/ft. Drilling 6" Boreholes 819ft. 1, 638.00
16 Percent Administration - Engineering -
Planning and Direction $12, 133. 28
Total Cost (Including Fertilizer, Seed, Lime,
Dynamite, etc.) $87,966.28
-338-
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TABLE 1 (continued)
PROJECT NO. 20
September, 1970
City of Monongahela, Washington County, Pennsylvania
Method: Removal of Vegetation - Installation of Surface Seal -
Injection of Fly Ash - Prevention of Erosion
(Contractor: Dragan &c Son)
Unit Cost
$16.80/hr.
12.00/hr.
5. 00/hr.
4.00/hr.
1.60/ft.
1.60/ft.
2. 00/ton
4. 00/ton
8. 00/hr.
Project Costs
Dozer
Hi-Lift
Chain Saws
Laborers
6" Vertical Boreholes
6" Angle Boreholes
Fly Ash
Top Soil
Truck
1,079-1/2 hrs. $18, 351.50
404 hrs.
1,092 hrs.
1,720 hrs.
13,784 ft.
418 ft.
2,284.075 tons
304 tons
412 hrs.
4
5
6
22
4
1
3
848.
460.
880.
054.
668.
568.
216.
296.
00
00
00
40
80
15
00
00
Misc. (Fertilizer,
Casing, etc. )
Seed Limestone,
24 Percent Allowance for Supervision
and Administration
,209. 10
16, 370. 18
$84,579.28
-339-
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TABLE 1 (continued)
PROJECT NO. 33 August, 1969
Ken Ridge Drive, Kennedy Township, Allegheny County, Pennsylvania
Method: Dry Fly Ash Injection - Fly Ash Slurry - Revegetation
(Contractor: Construction Methods , Inc.)
Unit Cost Project Costs
$18.00/hr. Hi-Lift Z36hrs. $4,248.00
5.60/hr. Laborers 202-1/2 hrs. 1,113.75
0.95/ft.
10. 00/unit
15. 00/unit
1.85/ton
0.50/lb.
3.00/ton
10.00/hr.
20.00/hr.
6" Boreholes
Basings w/caps
(injection holes)
Casing Adapters
Fly Ash
Grass Seed
Top Soil
High Pressure Slurry Pump
Challenge Truck Mixer
Misc.
24 Percent Administration and
6, 822 ft.
34
2
297.25 hrs.
250 Ibs.
325 tons
110 hrs.
170 hrs.
Engineering
6,480.90
340. 00
30.00
549.91
125. 00
975. 00
1, 100. 00
3, 400. 00
$18, 371. 56
4,409. 17
$22, 780. 73
PROJECT NO. 38 December, 1970
Peferman's Corners, Penn Hills Township, Allegheny County,
Pennsylvania
Method: Fly Ash Injection (Wet and Dry) - Revegetation
(Contractor: Allied Asphalt Company, Inc. )
Unit Cost Project Costs
$1.25/ft. Vertical Boreholes 9,530ft. $11,912.50
1.25/ft. Angle Boreholes 1,322ft. 1,652.50
2.00/ton Dry Fly Ash 340. 81 tons 681.63
6.50/C.Y. Fly Ash - Water Slurry 5.968.85C.Y. 38,797.50
Misc. Costs plus
24 Percent Allowance - Supervision and
Administration $34, 671. 77
$87, 715.90
-340-
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TABLE 1 (continued)
PROJECT NO. 39 January, 1972
Upper Tyrone Township, Fayette County, Pennsylvania
Method: Fly Ash Injection - Revegetation
Contractor: Allied Asphalt Company, Inc. )
Unit Cost
$24.00/hr.
15.00/hr.
7.00/hr.
1.00/ft.
20. 00/unit
20.00/unit
2.35/ton
6. 00/ton
18.00/ton
80. 00/ton
3.00/ft.
50.00/100#
unit
12.00/C. Y.
Project Costs
Dozer (D8)
Dozer (Tractor)
Laborers
6" Boreholes
Casing w/caps
(injection holes)
Casings w/caps
(inspection holes)
Fly Ash
Top Soil
Limestone
Fertilizer
3" Boreholes
Grass Seed
Wet Fly Ash
8 hrs.
96-1/2 hrs.
2,040 hrs.
15,418 ft.
34
4,444.86 tons
204.75 tons
3-1/2 tons
3-1/4 tons
620 ft.
3-1/2 100#
units
1,961.45 C.Y.
24 Percent Supervision and Administration
$ 192.00
1,447.50
14,280.00
15,418.00
680.00
60. 00
10,445.42
1, 228.50
63. 00
260.00
1, 860. 00
175.00
23, 537.40
$69,646.82
16,715.24
$86,362.06
-341-
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*Mt. Carmel (Project SL 304)
8, 000, 000 cu. yds. @ $1.28 per c.y. This figure includes drilling,
blasting, loading, hauling, spreading, quenching, backfill, mobili-
zation and demobilization.
A coal credit of $4. 50 to $4. 75 per ton was allowed for approximately
360, 000 tons of coal, (deduct)
**Kehley Run (Shenandoah) Project SL 309
1,100, 000 cu. yds. refuse and spoil material @ $1. 65/c. y.
4,300,000cu. yds. consolidated & solid material @ $1. 65/c. y.
2, 600, 000 cu. yds. backfill @ $0. 50/c. y.
14" pipeline and deep well pump installation (including power costs) $70, 000
85, 000 cu. yds. of clay seal @ $3. 20/c.y.
40,000cu. yds. of deep mine flushing @ $3. 60/c. y.
2,400 linear ft. 6" diameter boreholes @ $9. 00/foot
600, 000 tons coal credit @ $4. 35/ton (deduct)
***Baker Bank (Scranton) U.S. Bureau of Mines Demonstration Project
Bank contained an estimated 3. 5 million cubic yards of refuse, the section
of the bank used for the demonstration project contained an estimated 1. 1
million cubic yards. Two techniques were employed: 1) Quenching and
sluicing the hot material with available mine water, then bulldozing the
cooled refuse into an adjacent strip pit; 2) Quenching the hot refuse with
water cannons and a sprinkler system, a bulldozer was then used to rip
the quenched material and a tractor-scraper transported, spread and com-
pacted the extinguished material.
For technique No. 1 the cost was $0.66/c.y., costs for technique No. 2
were $0. 44/c. y.
-343-
-------
REFERENCES
1. Maneval, David R., 1969, Recent Advances in Extinguishment of Burning
Coal Refuse Banks for Air Pollution Reduction: Proc. Am. Chem. Soc.
_U (2) 27-41
2f McNay, Lewis M. , 1971, Coal Refuse Fires, An Environmental Hazard:
U.S. Bur. Mines Inf. Circ. 8515, 50 p.
3. Dougherty, John J. , 1969, Control of Mine Fires: West Virginia Univ. ,
Mining Extension Serv. Publ. , 89 p.
4. Magnuson, Malcolm O., 1972, Personal Communication: Project Coord-
inator, Mine Fire Control, U.S. Bur. Mines, Pittsburgh
5. Deyens, Willis, 1972, Personal Communication: Pa. Dept. Environ-
mental Resources, Wilkes Barre District Office
6. Yaccino, Michael, 1972. Personal Communication: Pa. Dept. Environ-
mental Resources, Pottsville District Office
7. Dierks, H. A., et al. , 1971, Three Mine Fire Control Projects in North-
eastern Pennsylvania: U.S. Bur. Mines Inf. Circ. 8524, 53 p.
-344-
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MINE SUBSIDENCE CONTROL
TABLE OF CONTENTS
^ Page No.
Introduction 347
Pressure Grouting of Mine Voids 347
Construction of Concrete Piers 348
Drilled Caissons 348
Grouted Aggregate Piers 348
Fly Ash Injection Method 349
Flushing Coal Mine Refuse 351
Controlled Mine Subsidence 353
References 355
LIST OF TABLES
1. Mine Stabilization Projects Using Fly Ash, Pennsylvania 350
2. Mine Stabilization Projects Utilizing Coal Mine Refuse, Northern
Anthracite Field, Pennsylvania 352
-345-
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-------
MINE SUBSIDENCE CONTROL
Introduction
The prevention and limitation of subsidence caused by underground
mining is an art which is rapidly becoming an exact science as recent appli-
cation and observation technology for controlling the damaging effects of
surface subsidence are put into effect. Most of the really significant tech-
nological developments have occurred in Pennsylvania as a result of the
funding available under the Operation Scarlift Program which permitted rapid
development of the needed technology.
Surface subsidence as a result of coal mining has been a problem in
the United States for over one hundred years, and in 1864, hydraulic stowing
was "invented" in the anthracite region of Pennsylvania to control subsidence'•*•).
Numerous papers have been published on mine subsidence, but probably one
of the most useful to the engineer is a recently reprinted publication (1972)
by the British Institution of Civil Engineers titled "Report on Mining Subsi-
dence"^). This report prepared by the Mining Subsidence Committee of the
Institution in 1959 discusses the types of subsidence movements and the
effects of mining subsidence on the stability and durability of all types of civil
engineering works and structures on or near the surface. It recommends
precautionary measures to be taken and methods of construction for structures,
bridges, roads and public utilities in areas where subsidence is or can be a
problem. An extensive bibliography of pertinent publications is included.
To satisfy the ever increasing demand for energy, more and more
land is being undermined to obtain coal, a prime energy source. As the
areal extent of undermined land increases along with a growing population
which is expanding into areas that were formerly mined or now being mined,
the necessity for effective control of mine subsidence becomes a pressing
need.
Several methods of subsidence control are discussed in this section
of the report. In recent years, the Commonwealth of Pennsylvania and the
U. S. Bureau of Mines have developed a great deal of experience in pneu-
matic and hydraulic injection of fly ash and prepared coal mine refuse into
mine voids for ground stabilization. Other methods such as drilled caissons
and grouted aggregate piers have been used in areas where heavy or valuable
structures are constructed on undermined land.
Pressure Grouting of Mine Voids
Pressure grouting of mine voids and the roof rock with cement grout
has been technically feasible for many years. The drawbacks have been sev-
eral, most notably, the high unit cost of the medium and the almost impossible
task of accurately estimating the grout take and thereby the total project cost.
If cost is not a factor, pressure grouting is the most positive stabilization
procedure, particularly with the addition of modern inspection tools such as
the borehole camera and television.
-347-
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Construction of Concrete Piers
A relatively simple technique, the construction of concrete piers
within the mine void is somewhat less expensive than pressure grouting,
but, has many important limitations on its applicability. Among these are
the need for a relatively competent roof strata and, most important, access
to the void to permit standard construction procedures to be carried out in
the dry.
Drilled Caissons
Drilled piers (caissons) have been utilized to support structures over
mine voids by drilling from the surface into the mine floor at the location of
the building column, placing shells, and then, filling the shells with concrete.
After the concrete has set, the structure can be framed in normal fashion. It
is necessary, however, that the floor be constructed as a structural floor,
supported on grade beams between the piers, since only the column points
are dependably supported. The average cost for a 30-inch drilled pier, in
medium hard rock, is about $40.00 per lineal foot, including all supplemental
costs. The unit cost of these units appears to be high, however, the available
bearing capacity is subject to so many factors controllable in design that almost
any conceivable load can be supported by varying the characteristics of each
caisson within a relatively narrow range. The drilled caisson is becoming
a standard method of supporting high and valuable loads over mines within
a 50 foot depth. It is believed that further development of the controlled
fly ash flushing method will soon lead toward package projects wherein both
structural and ground loads can be supported by a combination of drilled
piers and fly ash backfill of voids.
Grouted Aggregate Piers
The grouted aggregate pier method of mine void stablization is prob-
ably the most efficient technique yet devised for construction of valuable
structures on undermined land. The process has been applied sufficiently
often that considerable expertise has been developed, along with the efficient
observation and application tools. In this method six inch borings are made
to the floor of the void. Gravel or slag is placed in the mine void and spread
with the assistance of compressed air into a truncated conical form until
the top surface of the truncated cone achieves a minimum diameter of six
feet against the roof of the mine. The aggregate cone and the rock over the
void are then pressure grouted to an approximate diameter of six feet. The
grouted aggregate piers are normally spaced on 25 foot centers throughout
the area of concern, although the spacing can sometimes be increased to as
much as 40 feet depending on mine void conditions and the proposed use of
the property' '.
-348-
-------
Estimated unit costs for the grouted aggregate pier method are:
Drilling (6 inch diameter hole) $ 2.75 L.F.
Casing (6 inch O.D.) ' 1.50 L.F.
Photography (For job planning and control) 175.00/Day
Grouted Aggregate Pier 700. 00 to 1, 000. 00 Ea.
When it is considered that approximately 75 piers per acre are required
under standard conditions, it can be seen that this process is not cheap. It does,
however, provide a method of almost guaranteed stability that is well within the
cost structure of almost any significant development, particularly since location
may be an important factor in the economic consideration of a project site. Granted
the importance of location, then the approximate cost of $75, 000 per acre for
grouted aggregate piers becomes an easily handled item in the overall cost-benefit
ratio of the project.
Fly Ash Injection Method
The stabilization of mine voids by pneumatic injection of fly ash or hydraulic
injection of a fly ash slurry is a process employed by the Pennsylvania Department
of Environmental Resources to the level of a "Standard Specification" type of work.
Significant cost reductions have occurred in this method as contractors have gained
experience in equipment usage and the cost factors involved. The present overall
cost of fly ash injection is estimated at $4. 20 per cubic yard. This cost includes
all supplemental costs and offers, potentially, a low cost approach to stabilization,
particularly since the application cost is not apparently a function of depth with the
exception of the cost of borings.
There are several minor questionable features to the system, principally,
the surface supporting capacity of pneumatically injected fly ash is somewhat con-
jectural. The take at any particular site is difficult to predict and finally there
is some question as to whether the supply of fly ash is adequate within the areas
of need. This could result in increased overall costs because of transportation
costs. It would be desirable to see experimental projects carried out to deter-
mine the consolidation properties of the fly ash after being placed in a mine.
This information could provide reassurance that fly ash is the ultimate mine void
stabilizer that so many believe. If so, this method could be applied in place of other
methods which are much more expensive, but have been shown to offer stability
under heavy imposed loads.
Table 1 is a tabulation of recent fly ash injection mine stabilization pro-
jects performed under Pennsylvania's Operation Scarlift Program. The projects
cover a period from 1968 to 1971 and are arranged in order of decreasing cost
per acre of stabilization. When project location, areal extent of stabilization,
depth and thickness of void is considered, it is apparent that no cost trend can
be developed from the information presented in the table. The best unit cost esti-
mates for fly ash injection obtained from individuals familiar with this method
ranged from $4.00 to $4.50 per cubic yard. Allowance must be made for extra
deep borings, difficult site conditions, haulage distances and other factors which
could increase costs(4).
-349-
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-350-
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Flushing Coal Mine Refuse
A number of mine stabilization projects have been completed in the
Northern Anthracite Field of Pennsylvania using anthracite breaker refuse
crushed to minus one-half inch as the fill material^). The cost of the pro-
jects were borne jointly by Federal and State government and were part of
a program called "Operation Backfill. " The work consisted of the filling of
mine voids by the application of the "controlled flushing" and "blind flushing"
techniques. Table 2 presents cost data and volumes of coal refuse utilised
in 14 of these projects.
Quantities of various "pay items" used for Project ASP-1, the Pine
Brook Mine Project at Scranton, Pennsylvania were as follows:
Cubic yards placed by controlled flushing 491,955
Cubic yards placed by blind flushing 7, 956
Linear feet six (6) inch diameter boreholes 12, 053
Linear feet six (6) inch O.D. casing pipe 4, 885
Linear feet 12 inch diameter boreholes 396
Linear feet 12 inch O.D. casing pipe 173
Linear feet 28 inch diameter boreholes 202
Linear feet 28 inch O.D. casing pipe 220
This project was started in 1966 and completed in 1968. "Pay items"
are those which the Contractor submitted unit prices in his bidding proposal
and they are the only items for which payment was made. The price con-
tracted for per cubic yard of flushing included all costs for the crushing plant,
preparation of flush material, haulage, labor and materials incident to actual
placement underground. The price per foot of drilling the flushing boreholes
includes all labor and materials incidental thereto, likewise the installation of
casing pipe. Cost of installing hoisting equipment, headframes, fan, etc.,
is included in the unit price of the large diameter boreholes. Therefore, the
total amount paid for the entire project is the sum of the amounts obtained by
multiplying each of the few quantities bid on a unit price basis in the contract(5).
This was mostly a "controlled flushing" project and the cost on a per
cubic yard basis was $1.75. Project ASP-2, completed on the other side of
Scranton, the Morse School Project, had a cost of $3. 65 on a cubic yard basis.
Approximately 70 percent of the flushing on this project was "blind flushing"
which accounted for a much greater borehole footage, over 200, 000 linear feet
of borehole.
Another, newer method of backfilling abandoned mine workings is the
so-called Dowell System("), a slurry hydraulic injection process. In this sys-
tem locally available permeable materials, usually mine wastes, are crushed
and then pumped through a central borehole under pressure until the void is
filled. The method has several advantages, it results in removal of unsightly
surface wastes and require-s only one injection point which makes the process,
-351-
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TABLE 2
MINE STABILIZATION PROJECTS
UTILIZING COAL MINE REFUSE
NORTHERN ANTHRACITE FIELD, PENNSYLVANIA
Project No.
NRD-3
NR-32
NR-32A
NR-33
NR-34
NR-37
NR-39
NR-46
NR-55
NR-56
NR-10
PH&S-2
ASP-1
ASP-2
Location
Pitts ton
Scranton
Scranton
Scranton
Scranton
Scranton
Scranton
Scranton
Scranton
Scranton
Pitts ton
Scranton
Scranton
Scranton
Volume Filled
(Cubic Yards)
271,122
50,008
23,985
49,613
169,392
92,680
54,931
61,977
399,368
10,181
70,348
291,077
491,911
259,306
Total
Cost
$239,974
82,372
35,187
74,780
240,165
130,531
75,274
85,975
445,431
23,753
146,884
364,293
858,865
946,474
Cost Per
Cubic Yard
$0.89
1.65
1.47
1.51
1.42
1.41
1.37
1.39
1.12
2.33
2.09
1.25
1.75
3.65
-352-
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aesthetically, far more acceptable than other methods. On the other hand, the
process requires such extensive physical plant and pumping time that the appli-
cation cost appears high, even with the advantage of cost free materials. One
project, at Rock Springs, Wyoming, was completed with injection of 20,000
cubic yards of sandy waste at a cost of $8. 65 per cubic yard. Another project
is being performed at Scranton, Pennsylvania. This project will involve about
300, 000 cubic yards of anthracite mine waste and application costs are esti-
mated at $5.60 per cubic yard of, again, cost free material. The process is
not inexpensive, it does, however, seem to have a very real place in urban
areas and in other areas where disruption from multiple injection points has
high economic importance.
Controlled Mine Subsidence
For many years little was known about the nature of ground movement
and subsidence calculations were therefore very approximate. But in recent
years, affected areas have been carefully measured and observed and the
principles of ground movement cause by extraction of stratified deposits are
now more fully understood.
There is a new mining technique that was brought to this country from
Germany during the last decade and has only recently been put to use in bitum-
inous coal mines(7). This technique uses a special machine, known as a long-
wall miner, which removes all of the coal as the machine advances through
the seam; a set of automatic advancing jacks holds up the mine roof immediately
behind and parallel with the cutting bits. As the operation moves farther along
the coal deposit, the jacks are also moved, leaving behind a completely mined-
out area. The surface over this area settles, but because 100 percent of the
coal has been removed, the settling or subsidence is uniform.
Uniform subsidence seldom causes damage to any surface structures
which lie directly and entirely above the mining operation. The damage occurs
where there are variations in the degree of subsidence. Where, for example,
one part of a house stays at the same level and the rest of the house drops sev-
eral inches. Traditional mining techniques, with their coal pillars interspersed
throughout the post-mining cavity, can and do cause this variable subsidence;
the long-wall miner does not. In virtually all cases where the long-wall method
has been used, little or no damage to surface structures has been reported,
although there are frequently cases where wells run dry because of the fractur-
ing of aquifers caused by subsidence.
Formulas have been worked out to determine how much subsidence will
occur as the result of a given long-wall mining operation. If a six foot thick
coal seam lying 100 feet beneath the surface is removed, for example, the
overlying surface will sink six inches; if the seam is thinner or lies deeper,
the subsidence will be less.
-353-
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Since there will be a drop-off of the land surface at the perimeter of
each long-wall mining operation, care must be taken to plan the operation so
that there is no surface structure sitting athwart this perimeter. For this
reason, the new mining method is most suitable in areas which are rural and
where the coal deposits occur in large blocks.
Only a brief mention has been made of pillar mining in previous para-
graphs. In room and pillar mining, it is not possible to predict the develop-
ment of subsidence, since there is such a great variety of pillar sizes and
depths. Pillars may fail after years have elapsed, the amount of movement
depending on the room space available into which they can crush. Or the
pillars may be forced into a soft floor such as fireclay. This will result in
a lowering of the surface just as though the pillars had been crushed and spread.
Where the floor is soft the limiting factors are the thickness of the soft floor
stratum and the space available in the rooms into which the pillars can be forced.
In general it has been found that the smallest safe dimension for pillars is about
one-tenth the depth of the coal seam.
- 354-
-------
REFERENCES
1. Spicer, T. S. , 1971, Pennsylvania Anthracite Refuse, A Summary of a
Literature Survey on Utilization and Disposal; Pa. State Univ. Spec.
Res. Report SR-79, 43 p.
2. Institution of Civil Engineers, 1959, Report on Mining Subsidence: Mining
Subsidence Committee, Great Britain, 52 p.
3. Sturges, F. C. and Clark, J. H. , 1970, Fly Ash - The Answer to Mine
Subsidence Protection; Coal Mining and Processing, ( ), p.
4. Pennsylvania Department of Environmental Resources, 1972, Information
in Files of Office of Engineering and Construction: Harrisburg
5. Charmbury, H. B. , Smith, G. E. and Maneval, D. R. , 1968, Subsidence
Control in the Anthracite Fields of Pennsylvania: ASCE Ann. Meet, and
Nat. Meet. Structural Eng. , Pittsburgh, 22 p.
6. U. S. Bureau of Mines, 1972, Final Environmental Impact Statement,
Demonstration - Hydraulic Backfilling of Mine .Voids, Scranton, Penn-
sylvania: May 15, 1972, 93 p. including Appendix.
7. Maneval, David R. , 1972, Coal Mining Vs. Environment, A Reconciliation
in Pennsylvania: Appalachia, ^(4), p. 10-40.
-355-
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-------
PART B
ABATEMENT OF POLLUTION FROM SOURCES
OTHER THAN COAL MINING
-357-
-------
-------
COST ESTIMATES FOR AIR POLLUTION CONTROL EQUIPMENT
TABLE OF CONTENTS
Page No.
Introduction 361
Classes of Air Pollution Control Equipment 361
Cost Estimates for Pollution Control 362
Incinerator Emissions and Control of Odors 364
Stacks for Air Pollution Control 364
References 384
LIST OF TABLES
1. National Ambient Air Quality Standards 365
2. Typical Incinerator Emissions Compared to Open Burning 366
3. Pollution Control Costs for 50,000 ACFM Units - 1972 367
4. Installation Costs as a Percentage of Purchase Costs for
Four Generic Types of Control Devices - 1968 367
5. Annual Maintenance Cost Factors for Four Generic Types
of Control Devices in 1967-68 372
6. Approximate Characteristics of Dust and Mist Collection
Equipment 373
7. Industrial Process and Control Summary 374
8. Advantages and Disadvantages of Collection Devices 375
9. Actual Costs for Air Pollution Control Equipment in
Pennsylvania, 1971-1972 377
10. Fuel Cost Comparison for Control of Odors 383
-359-
-------
LIST OF FIGURES
Page No.
1. Gas Cleaning Systems Cost Flow Diagram 366
2. Estimated 1967-68 Purchase Costs for Fabric Filters 368
3. Estimated 1967-68 Purchase Costs for Wet Scrubbers 369
4. Estimated 1967-68 Purchase Costs for Electrostatic
Precipitators 370
5. Estimated 1967-68 Purchase Costs for Mechanical
Collectors 371
-360-
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COST ESTIMATES FOR AIR POLLUTION CONTROL EQUIPMENT
Cost estimates performed without the benefit of design or technical
specifications are nebulous at best. Stricter emission standards and rapidly
changing technology in the field of air pollution control have brought into play
far too many variables to enable accurate predictions. The year data was
compiled is very important, since equipment, material and labor costs have
risen each year. The data used in this section of the report ranges from
less than a year to four years in age. However, before a cost comparison
was made for a fixed size unit, costs were updated to a July, 1972 base using
"Marshall and Stevens Index" as published in Chemical Engineering Magazine.
The volume of gas to be cleaned is the single most important factor
in determining the cost of an air pollution control device and the removal
efficiencies for contaminants are paramount in deciding which type of equip-
ment is to be used. The unit selected must be able to produce an effluent
capable of meeting the National Ambient Air Quality Standards established
by the Environmental Protection Agency (Table 1).
Two other factors affecting equipment costs are system design and
process control. Their importance cannot be overemphasized. A poor de-
sign will increase emissions or amounts of exhaust gas to be treated, thus
making cleaning more difficult and more expensive. Improper operation of
the best design possible will result in the same outcome.
Figure 1 summarizes the most important factors affecting the final
net cost of an air pollution control system.
Classes of Air Pollution Control Equipment
Four classes of pollution control equipment are analyzed as well as
odor control devices which are considered separately. They are as follows:
1. Mechanical Collectors - This type of collector is used for removal of
particUlate emissions only. They rely on gravity, particle inertia or
centrifugal force to effect removals. The types of units included in
this category are: 1) settling chambers, 2) inertial separators and 3)
cyclones. Efficiencies depend heavily upon the particle characteristics,
removal percentages decreasing rapidly with decreasing particle size.
These units are most effective in collecting particles ten microns in
size or larger. Efficiencies can vary from 20-90 percent. Overall,
mechanical collectors are the least expensive equipment to purchase
and operate. However, low removal efficiency and large space re-
quirements make this equipment undesirable as a single unit installr
ation. Generally, they are used in series with other kinds of units as
a pretreatment stage. Contaminants are collected in a dust bin, further
disposal being to a landfill or similar area.
-361-
-------
2. Wet Scrubbers - This class of devices uses a liquid, usually water, to aid
in the removal of contaminants. They are effective in removing gas and
vapor phase pollutants as well as particulates. The units are effective at
high temperature and are not significantly affected by particle size or load-
ings. Efficiencies for particles ranging in size from submicron to ten
microns vary from 80-99.5 percent. According to Cross(^), scrubbers
are the most widely used control equipment and have been recommended as
the only economical and effective control device for moderately sized in-
cinerators (less than 1, 000 Ib. /hr. capacity). Sulfur dioxide can also be
controlled with scrubbers. The disadvantage of wet collectors include
corrosion problems, wastewater disposal, contamination of the exhaust
gas by liquid entrainment, freezing in cold weather and visibility of water
vapors from stacks during certain weather conditions. Costs vary with
respect to the amount of pressure drop through the unit, the construction
materials and the unit size.
3. Electrostatic Precipitators - This type of device employs the principle of
particle ionization by a discharge electrode and then entrapment by a col-
lecting plate consisting of a grounded electrode. They are most effective
with particles ranging from one to ten microns. Efficiencies start at 60
percent and can exceed 99.5 percent. A mechanical collector generally
precedes a precipitator because large particles can cause damage to the
discharge electrodes. Agglomerates of particles are formed and these
are collected below the grounded electrodes. Disposal to a landfill or a
similar site is easily accomplished. Unit capacities can be as high as
three million cubic feet per minute (CFM), pressures can approach 150
pounds per square inch of gas (PSIG) and gas temperatures can be as high
as 1,200° F. Electrical power is consumed at the rate of 50 to 500 watts
per 1, 000 CFM. Electrical costs in Western Pennsylvania are between
$0.01 and $0.02 per kilowatt hour for units of 50,000 CFM capacity.
4. Filters - In this type of unit an exhaust gas is passed through a porous
structure. The units operate effectively on all sizes of particles, effici-
ency being determined by the type of filtering material used. Removal
values can approach 99.99 percent in some instances. This type of unit
is particularly valuable when the contaminant can be recycled for use
elsewhere. Temperatures usually must be kept below 550° F, however,
this limitation is a function of filter material properties. The filter mat-
erial or fabric is subject to chemical attack and collection efficiency is
affected by humidity. Unit costs vary with the type of shaker (used to clean
filter material), the reuseability of filter material, unit size and the amount
of pressure drop.
Cost Estimates for Pollution Control
Table 3 is a tabulation of cost estimates for the four classes of pollution
control equipment based on a 50, 000 actual cubic feet per minute (ACFM) unit
with average to high efficiency. The results are in dollar cost for purchase and
-362-
-------
installation of the unit per 1, 000 ACFM size. An "average" unit is assumed.
Capital costs would be affected by special design factors, unusual installation
problems, a requirement for very high efficiencies, construction with other
than steel and other variables. The cost estimates in Table 3 are for a fixed
size unit. Variations in cost relative to size for each class of equipment are
shown in Figures 2 through 5.
Table 4 from Ernst & Ernst(^) presents installation costs as a per-
centage of capitalized purchase cost. When capitalized purchase costs are
added to the capitalized installation cost, the sum is the annual capital cost.
Table 5, also from this publication, is based on information from several
sources which suggests maintenance costs can be approximated by using the
cost factors in the table. Local labor cost and price conditions can cause
wide departures from the factors shown and should be used when available.
Table 6, reproduced from Stern(^) shows relative cost and character-
istics of dust and mist collection equipment. A summary of important indus-
tries, their pollutant sources, particulate pollutants, and air cleaning techni-
ques is presented in Table 7. Table 8 lists advantages and disadvantages for
each of the general types of collection devices. Tables 7 and 8 were repro-
duced from Kerbec(^).
Actual 1971-72 capital and operating costs, design data, and other
pertinent information for air pollution control equipment is presented in Table
9. This unpublished information covering various industries was obtained
from Mr. Douglas Lesher, Pennsylvania Department of Environmental Re-
sources^).
presents data on expenditures for air pollution control by 330
firms in various industries for 1967. The cost figures are five years old and
air quality standards and equipment design have changed considerably since
then. On the average, each firm spent:
Capital Equipment Costs $88,400
Installation Costs 53,200
Operating Costs 46,550
The breakdown in operating costs and percent of total for each item
Power, fuel and water $19,840 43%
Materials and spare parts 5,100 10-11%
Maintenance and labor 7, 100 15-16%
Collected waste disposal 14, 510 31%
$46,550
-363-
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Incinerator Emissions and Control of Odors
Emissions from incinerators are not constant in character or amount.
The amounts and kinds of emissions will vary with the character of the mat-
erial being burned. Incinerators are capable of producing all six of the cate-
gories of pollutants recognized by the Environmental Protection Agency.
Table 2 shows typical amounts of incinerator emissions, and as a basis of
reference, they are compared with open burning. Odor can also be a prob-
lem in incineration, especially when the material incinerated has a high
organic content, a condition to be expected in municipal waste incineration.
The control of odors from organic sources is usually accomplished by
heating the exhaust gas to 1400° F for a period of 0.5 second. For practical
purposes, three types of equipment are available to achieve odor control.
1. Afterburner
2. Afterburner with Energy Recovery
3. Thermal Regenerative System
A fuel cost comparison was presented by Mueller'") to show the sig-
nificance of thermal energy and system exhaust temperature (Table 10).
Stacks for Air Pollution Control
Stacks are air pollution control equipment since their purpose is to
1) reduce temperatures of exhaust gases, 2) increase the dispersion of con-
taminents to achieve lower ground concentrations, and 3) reduce sulfur di-
oxide concentrations. According to First'"), current estimating practice for
construction costs of tall stacks is $1, 000 per foot for the first 600 feet and
$2, 500 for each additional foot.
-364-
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TABLE 1
NATIONAL AMBIENT AIR QUALITY STANDARDS
ENVIRONMENTAL PROTECTION AGENCY
PRIMARY STANDARDS - are to protect public health.
SECONDARY STANDARDS - are to protect against effects on soil,
water, vegetation, materials, animals, weather, visibility and
personal comfort and well-being.
I. SULFUR OXIDES - primarily from the combustion of sulfur
containing fossil fuels.
PRIMARY - 80 micrograms/cubic meter (0.03 ppm) annual
arithmetic mean.
- 365 micrograms/cubic meter (0.14 ppm) as a maximum
24 hour concentration not to be exceeded more than
once a. year.
SECONDARY - 60 micrograms/cubic meter (0.02 ppm) annual
arithmetic mean.
- 260 micrograms/cubic meter (0.1 ppm) maximum
24 hours concentration not to be exceeded more
than once a year.
- 1300 micrograms/cubic meter (0.5 ppm) as a
maximum three hour concentration not to be
exceeded more than once a year.
II. PARTICULATE MATTER - Industrial processes or human activity.
PRIMARY - 75 micrograms/cubic meter annual geometric mean.
- 260 micrograms/cubic meter as a maximum 24 hour
concentration not to be exceeded more than once
a year.
SECONDARY - 60 micrograms/cubic meter annual geometric mean.
- 150 micrograms/cubic meter as a maximum 24 hour
concentration not to be exceeded more than once
a year.
III. CARBON MONOXIDE - by product of incomplete burning of carbon
containing fuels.
PRIMARY/SECONDARY - 10 milligrams/cubic meter (9 ppm) maximum
eight hour concentration not to be ex-
ceeded more than once a year.
- 40 milligrams/cubic meter (35 ppm) maxi-
mum one hour concentration not to be
exceeded more than once a year.
IV. PHOTOCHEMICAL OXIDANTS - chief source is when hydrocarbons
and nitrogen oxides are exposed to sunlight.
PRIMAKY/SECONDATjY - 160 micrograns/cubic meter (0.08 ppm)
as aTriaximuirT'oneThour concentration not to be exceeded
more than once a year.
V. HYDROCARBONS - Processing, marketing and use of petroleum
products.
PRIMARY/SECONDARY - 160 microqrams/cubic meter (0.24 ppm)
aca~iiiaxin"ulvrTFiree hour concentration ( 6 to 9 AM) not to
be exceeded more than once a year.
VI. NITROGEN OXIDFS - originate from high temperature combustion
processes.
P_RIf-^RY/Sj;cOFD^!-!Y - 100 miciograms/cubic meter (0.05 ppm)
annual aritnraetic inean.
-------
FIGURE 1
Operation and operational
variables Influencing
control costs
Gas Cleaning System
factors influencing
control costs
Cost areas determining
the net cost of control
GAS CLEANING SYSTEMS COST FLOW DIAGRAM
Source: Ernst & Ernst,
TABLE 2
TYPICAL INCINERATOR EMISSIONS COMPARED TO OPEN BURNING
Incinerator Emissions Open Burning Emissions
Type of Emission Pounds/Ton Refuse Fired Pounds/Ton Refuse Fired
Particulate
SO^
X
CO
HC
NOX
Photochemical
30
1.5
1
1.5
2
NA
16
1
85
30
6
NA
Source: Engdahl, 1968(2)
-366-
-------
TABLE 3
POLLUTION CONTROL COSTS FOR 50, 000 ACFM UNITS*
(DOLLARS/1, 000 ACFM)
Purchase Cost
Installation Cost
Total Capital Cost
Annual Operating Cost
EFFICIENCIES
Mechanical
Separators
194
97
291
17
50-90%
Electrostatic
Precipitators
814
570
1, 384
ZO
98-99+%
i Filters 5
544
440
984
60**
98-99+%
scrubbers
556
526
1, 082
46
95+%
*From various sources, Updated to July, 1972 using Marshall and Stevens
Index
**Variable depending on type of filter media used.
TABLE 4
INSTALLATION COSTS AS A PERCENTAGE OF PURCHASE COSTS
FOR FOUR GENERIC TYPES OF CONTROL DEVICES - 1968
Generic Low
Type Percent
Mechanical Collector
Wet Scrubber
Electrostatic Precipitator
Fabric Filter
40
50
35
75
Mean
Percent
50
100
70
80
High
Percent
100
200
100
100
Extreme High
Percent
400
400
400
400
Reproduced from: Ernst & Ernst,
-367-
-------
FIGURE 2
ESTIMATED 1967-68 PURCHASE COSTS FOR FABRIC FILTERS
(LOG SCALES)
600
400
300
200
PURCHASE COST
( $ X I03 )
200 400 600 BOO 1000
GAS VOLUME THROUGH COLLECTOR
(ACFM X I03)
PURCHASE COST (AMOUNT CHARGED BY MANUFACTURER)
• CAPITALIZED PURCHASE COST (62/3 % DEPRECIATION + 6 2/3 %
ADDITIONAL CHARGES TO CAPITAL), EXCLUDING INSTALLATION
Reproduced From: Ernst & Ernst, 1968^)
-368-
-------
FIGURE 3
ESTIMATED 1967-68 PURCHASE COSTS FOR WET SCRUBBERS
(LOG SCALES)
PURCHASE COST
( $ X 103 )
6 8 10
20
40 60 60 100
£00
400 600 800 1000
GAS VOLUME THROUGH COLLECTOR
(ACFM X 105)
PURCHASE COST (AMOUNT CHARGED BY MANUFACTURER)
CAPITALIZED PURCHASE COST (62/3% DEPRECIATION + 6 2/3 % ADDITIONAL
CHARGES TO CAPITAL), EXCLUDING INSTALLATION
Reproduced From: Ernst & Ernst, 1968^)
-369-
-------
FIGURE 4
ESTIMATED 1967-68 PURCHASE COSTS
FOR ELECTROSTATIC PRECIPITATORS
(LOG SCALES)
PURCHASE COST
( $X I03
40 60 80 100
200
400 600 800 1000
GAS VOLUME THROUGH COLLECTOR
(ACFM X 1C3)
PURCHASE COST (AMOUNT CHARGED BY MANUFACTURER)
' CAPITALIZED PURCHASE COST (6 Z/3 % DEPRECIATION + 6 2/3 %
ADDITIONAL CHARGES TO CAPITAL), EXCLUDING WSTALLATION
Reproduced From: Ernst & Ernst, 1968(1I
-370-
-------
FIGURE 5
ESTIMATED 1967-68 PURCHASE COSTS FOR MECHANICAL COLLECTORS
(LOG SCALES)
PURCHASE COST
( $ X I03 )
10
20
60 60 100
200
400 600 800 1000
GAS VOLUME THROUGH COLLECTOR
(ACFM X I03)
PURCHASE COST (AMOUNT CHARGED BY MANUFACTURER)
' CAPITALIZED PURCHASE COST (6 2/3 % DEPRECIATION + 6 2/3 %
ADDITIONAL CHARGES TO CAPITAL), EXCLUDIN6 INSTALLATION
Reproduced From: Ernst & Ernst, 1968(1)
-371-
-------
TABLE 5
ANNUAL MAINTENANCE COST FACTORS FOR FOUR GENERIC
TYPES OF CONTROL DEVICES IN 1967-1968
Generic Type
Mechanical Collectors
Wet Scrubbers
Electrostatic Precipitators
Fabric Filters
Low
0.005
0. 02
0.01
0.02
Cost ($/ACFM)
Mean
0.015
0.04
0.02
0.05
High
0.025
0.06
0.03
0.08
Reproduced From: Ernst & Ernst, 1968(1)
-372-
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REFERENCES
1. Ernst & Ernst, 1968, A Rapid Cost Estimating Method for Air Pollution
Control Equipment: Rept. to U.S. Public Health Service, Contract No.
PH 86-68-37, 41 p.
2. Engdahl, Richard B., 1968, Stationary Combustion Sources: Chapter 32
in Air Pollution, Vol. Ill, ed. Stern, Arthur C., New York, Academic
Press, 866 p.
3. Cross, Frank L. , Jr., 1972, Planning Incineration Without Air Pollution;
Pollution Engineering 4_ (4), p. 48-49
4. Stern, Arthur C., 1968, Efficiency, Application and Selection of Collectors:
in Air Pollution. Vol. Ill, Ed. Stern, Arthur C., New York, Academic Press,
866 p.
5. Kerbec, Matthew J. , 1971, Your Government and the Environment, An
Annual Reference: Vol. I, Arlington, Va., Output Systems Corp.
6. Lesher, Douglas, 1972, Personal Communication; Unpublished data com-
piled by Pennsylvania Department of Environmental Resources, Harrisburg
7. Lund, Herbert F., 1971, Industrial Pollution Control Handbook: New York,
McGraw-Hill
8. Mueller, James H., 1971, Cost Comparison for Burning Fumes and Odors;
Pollution Engineering _3 (6), p. 18-20
9. First, Melvin W., 1968, Process and System Control: in Air Pollution,
Vol. Ill, ed. Stern, Arthur C. , New York, Academic Press, 866 p.
-384-
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SOLID WASTES HANDLING AND DISPOSAL COSTS
TABLE OF CONTENTS
Page No.
Collection and Transportation 387
Disposal Methods 388
Open and Covered Dumping 389
Sanitary Landfills 389
Incineration 390
Composting 394
Experimental Solid Waste Disposal and Recovery Techniques 396
Pyrolysis 396
Biological Fractionation 396
Recycling 396
References 398
LIST OF TABLES
1. Cost of Compacted Waste Transported in Containers -
Vermont 388
2. Principal Components of a Municipal Incinerator and
Costs - New York City 392
LIST OF FIGURES
1. Sanitary Landfill Operating Costs 391
2. Capital Costs of Municipal Incinerators 393
3. Capital Costs of Compost Systems 395
4. Operating Costs for Compost Systems 395
-385-
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SOLID WASTES HANDLING AND DISPOSAL COSTS
The primary purpose of this section is to analyze presently available
solid waste handling and disposal techniques and determine unit costs for each
such technique discussed. The study is intended to provide information neces-
sary to evaluate the cost of solid waste management remedial programs in the
Monongahela River Basin. Although many of the cost analyses given are de-
veloped for areas other than the Monongahela River Basin, the capital and
operating cost figures are applicable to the region with the exception of land
acquisition requirements and labor costs which may be unique to the particular
area reported.
Solid waste management involves the following elements: collection and
transportation, processing and ultimate disposal.
Collection and Transportation
In urban and suburban areas, the most common methods of collection
include municipal collection, contract with a private firm and private col-
lection service. In any case, refuse is normally collected in a compactor
truck which transports the wastes to either the processing and disposal site
or to a central transfer station. Toftner and Clark' ' recommend the use of
transfer stations and size reduction techniques to reduce costs when long hauls
are necessary or when large areas are serviced. Another study by Kramer^)
suggests the use of transfer stations if the disposal facility is more than ten
miles from the collection area. Kramer lists advantages of transfer stations
as: 1) reduced cost of transportation; 2) more efficient use of collector trucks;
3) modest capital cost; and 4) reduced vehicle requirement. The capital costs
for such a station including one tractor and two trailers is given as $1, 620 per
ton per day capacity. Estimated operating costs for a 15 mile haul using a
transfer station are given as $0. 17 to $0.27 per ton-mile while the cost of
packer truck hauling over the same distance is estimated as $0. 18 to $0.40
per ton-mile.
In rural areas, collection and disposal are more difficult and more
costly than in urban and suburban areas. Inadequate collection services in
rural areas lead to unsightly dumping or open burning of refuse. In areas
of Pennsylvania infrequent or nonexistant collection services have led to the
infestation of the State with over 2,600 roadside dumps and allowance of open
burning of domestic refuse in many municipalities (Toftner and Clark^ ').
Andres and Cope'^) recommend a system of containerized storage and trans-
fer for rural areas. The stated goal is to eliminate several existing dumps
by promoting individual refuse disposal in 8 to 40 cubic yard containers placed
at central locations and transfer of the containerized waste to a single cen-
trally located sanitary landfill weekly. The annual cost per ton including
amortization for containers and transfer to landfills was estimated to range
from $13. 63 to $17. 89 as compared to a $17. 39 annual cost for operation and
maintenance of individual community modified sanitary landfills. A similar
-387-
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study was conducted in Vermont (Cacioppi, et al. ^ '). Costs were estimated
on the basis of the number of cubic yards of compacted waste transported to
sites various distances from the collection point in 35 cubic yard containers.
Compactor and container leasing costs were estimated at $235 per month, and
the charge for disposal at $25 per container. An average of one hour travel
time for 30 miles and a time of one-half hour for unloading was assumed. On
the basis of 500 pounds per cubic yard compacted, a cost per container load
is given. For this study the costs have been converted to a cost per ton of
compacted waste. The data is reproduced in Table 1.
TABLE 1
Container Site
Distance from
Disposal Site
(Miles)
3
6
9
12
15
18
21
24
27
30
Cost/Ton
Times Per
1
10.23
10.43
10.64
10.85
11.05
11.26
11.47
11.67
11.87
12.08
@ 8.75 Ton per
Container
Week Containers Emptied
2 3
6.67
6.88
7.09
7.29
7.50
7.71
7.98
8. 11
8.32
8.53
5.64
5.88
6.05
6.26
6.48
6.67
6.88
7.08
7.29
7.49
Source: Solid Waste Section, Environmental Protection Division
Agency of Environmental Conservation, State of Vermont
in Cacioppi et al., 1970(4)
The data may be extrapolated to greater distances at a rate of $0. 07
per ton-mile. The report states that the containerization system is highly
suitable for rural areas and small communities and is sanitary, flexible and
economic.
Disposal Methods
The conventional solid waste disposal methods include open dumping,
sanitary landfill, incineration and composting. Some advanced disposal and
recovery or recycling techniques are also known, such as pyrolysis, biologi-
cal fractionation, and various separation processes; however, most of these
techniques are still in the experimental stage.
-388-
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Open and Covered Dumping
Open dumping is the most common method of solid waste disposal in
some areas of the United States, although it is by far the least desirable
method. No direct cost figures are available for open dumping; however, the
intangible costs of unsanitary conditions, ground and surface water pollution,
air pollution, insect and rodent problems, and aesthetic degradation may be
associated with this method.
Covered dumping is similar to open dumping except that the refuse is
periodically covered with soil. The disadvantages of covered dumping are
the same as those mentioned for open dumping. Vermont has estimated costs
for closing and sealing dumping sites to be $8, 000 per acre (Cacioppi, et al.' ').
Sanitary Landfills
Sanitary landfill techniques are the most practical and economical
methods of solid waste disposal in many areas. Two basic methods of sani-
tary landfill exist, trench fill and area fill. The area landfill involves the
filling of large low-lying areas with cells of refuse compacted and covered
with soil at regular intervals. The trench method involves excavation of
trenches, filling with refuse and recovering the trenches with soil. The soil
cover should be two feet deep over the refuse cells (Golueke(^)). The refuse
layers should not exceed five to six feet in depth and should be compacted be-
fore being covered.
In several areas of the anthracite and bituminous coal regions of Appa-
lachia, abandoned strip mines are used for sanitary landfills. The use of
strip mines not only solves local solid waste disposal problems, but may also
lead to restoration of the strip mine areas. Emrich and Landon(") investigated
five strip mine landfill sites in Western Pennsylvania. They found little or no
ground or surface water pollution where care is taken to avoid permeable or
fractured rock.
For either the area fill or trench fill method equipment requirements
range from a single crawler tractor with dozer blade or bullclaw attachment
for smaller operations to one bulldozer, compacting equipment, water trucks
and earth movers for larger sanitary landfills. One bulldozer of the 4, 700
pound gross weight size will handle 250 tons of solid waste per day (Golueke^)).
Sanitary landfill costs will depend on the population served, size of the
landfill, and the equipment required. Initial investments are variable depend-
ing on the price of the property acquired. The initial land costs may be par-
tially or completely offset by restoration of the completed landfill for develop-
ment purposes. Operating costs are more definable, and several costs of
operation are given in the literature. Kramer(^) gives operating costs of $1.65
to $2. 10 per ton for a 300 acre site handling 96, 000 to 150, 000 tons per year.
In Vermont, sanitary landfill operation costs are estimated to range from
-389-
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$0.60 to $3.00 per ton depending on the amount of waste to be disposed (Cacioppi,
et al. v'*) Ralph Stone and Company^'' gives costs of $1.50 per ton for sanitary
landfill disposal. Sorg and Hickman(°) have stated that wages account for 40 to
50 percent of costs; equipment, 30 percent; and cover material, administration
and overhead, 20 percent. Operating costs developed by Sorg and Hickman are
presented in Figure 1.
Incineration
Modern incineration involves controlled burning of solid wastes in a
closed vessel at high temperatures. The solid waste may be batch fed or con-
tinuously fed onto agitating grates where primary combustion occurs. Ashes
and noncombustables are fed into hoppers for disposal. The smoke, exhaust
gases and fly ash are directed into a secondary combustion chamber where they
are burned at temperatures of 1,500 to 1, 800 degrees F (Flower(9)). The gases
then flow through settling chambers for removal of heavy particulates and then
through various gas cleaning devices to the exhaust stack.
Incineration reduces the volume of waste to be disposed of to 10 to 30
percent of its original volume (Engdahl(lO)). ^he residues may be landfilled
directly or separated by mechanical and/or magnetic devices for recovery of
ferrous metals and glass. Gilbertson and Black'*M have found landfill or ash
residues to cost approximately $1.00 per ton.
Gouleke(S) has listed equipment needed for incineration of municipal
solid waste. A storage pit or hopper holding an amount equal to 24 hours of
burning capacity is needed for receiving and storing refuse. A bridge crane,
a charging hopper, a feeding and drying stoker and a burning stoker are needed
for charging the incinerator. The incinerator should have primary and second-
ary combustion chambers lined with refractory materials and various gas clean-
ing chambers, flues and dampers. Ash hoppers and conveyors must be provided
for removal of residues. Various instrumentation for temperature measure-
ment, draft gaging and stack gas monitoring should also be provided. Finally,
a landfill site is necessary for disposal of the incinerator residues.
Michaels^ ' in 1956 reported the capital costs of municipal incinerators
to range from $3, 000 to $4, 000 per ton of 24 hour capacity with buildings account-
ing for 40 to 76 percent, furnaces and auxilary equipment accounting for 18 to
24 percent and stacks accounting for 4.5 to 11 percent of the total capital cost.
More recently, Cacioppi, et al., 1970(4) reported capital costs to range from
$8, 000 to $11, 000 per ton of 24 hour capacity.
Greeley(13) listed the capital costs of municipal incinerators for New
York City by component. These unit capital costs are reproduced in Table 2.
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FIGURE I
SANITARY LANDFILL OPERATING COSTS
4.00
3.00
o
g 2.00
CL
O
o
1.00
0
100,000 200,000 300,000 400,000 500,000
TONS PER YEAR
Reproduced From "Sanitary Landfill Facts"
Thomas J. Sorg and H. Lanier Hickman, Jr 1970
PHS Publication No. 1792
-391-
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TABLE 2
PRINCIPAL COMPONENTS OF A MUNICIPAL
INCINERATOR AND COSTS
Unit Cost Per Ton
Item Of Rated Capacity
Scales, roadways, dumping rail and enclosing wall $ 100
Storage bin 200
Cranes 225
Flues and fly ash removal facilities 400
Chimneys 300
Furnaces 1,200
Inside Flues 85
Building and enclosure 1,415
Miscellaneous 75_
Total $4, 000
Source: Greeley, S. A., "Background of Design Criteria for Municipal
Incinerators - The Designer's View," JAPCA 6(3)133-9, 1956.
Further, Drobny, et al.(14) give total capital costs of various sizes of
municipal incinerators based on conventional engineering estimating factors.
A portion of their data is reproduced in Figure 2 for construction of inciner-
ators with conventional refractory and no waste heat recovery.
Operating costs for municipal incinerators are highly variable and
primarily related to the size capacity of the units and the percent of capacity
use per day. Several authors have reported operating costs for municipal
incinerators. Rogusv-'1-') reporting on large incinerators of approximately
1, 000 ton per day capacity in New York found costs to vary from $4.78 per
ton for older plants to $2. 39 per ton for newer design plants. Gilbertson and
Black(H) found operating costs to average $3.00 per ton in the Washington,
D. C. area. The Committe on Refuse Disposal, APWA(16) reported unit costs
for municipal incineration in six major U.S. cities to range from $2.28 to
$6.49 per ton on a 1959 base. A unit cost of $8.53 per ton including the cost
of disposal of ash and inerts was estimated for incineration by the City of
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co
cc
8
J 7
fe 6
co
3 5
8
Q_
<
O
0
FIGURE 2
CAPITAL COSTS OF MUNICIPAL INCINERATORS
200
400
600
800
1000
1200
CAPACITY-TONS PER DAY
From Drobny, N. L et a I. Recovery and Utilization of Municipal Waste US. EPA 1971
-393-
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Santa Clara, California (Ralph Stone and Company^''). Golueke^ ' found incin-
eration costs to vary from $4.00 to $12.00 excluding pollution control devices
in the Oakland, California area. Unit costs estimated by Kramer(^) ranged
from $6.50 to $8.40 per ton for two 300 ton per day capacity incinerators for
Clark County, Ohio. Costs for incineration in the state of Vermont were esti-
mated to range from $7. 00 to $11. 00 per ton (Cacioppi, et al. (4)).
Composting
Composting, presently more common to Europe than to the United States,
is a biological digestion process whereby the organic components of refuse are
degraded into a humus-like product. The process involves the screening of
refuse to remove nonorganic materials and biological oxidation of the remaining
organics for a period of two to five weeks. The cured compost may be used as
a soil conditioner, but because its nutrient content is low, it does not make a
good fertilizer.
In the United States composting has not been too attractive because it is
not economically competitive with other disposal methods and because no major
United States markets have yet developed for compost. Additionally, since the
bulk of solid waste is produced in large urban areas and compost would be util-
ized in rural areas, the transportation costs to move large volumes long dis-
tances would often be prohibitive.
Estimated costs for composting operations in Vermont were estimated
to average as high as $8. 00 per ton. A composting demonstration plant in
Gainesville, Florida had operating costs of $6.25 per ton. Goleuke^ ' gives
estimated operating costs for composting of $7.00 to $8.50 per ton to serve a
population equivalent of 100,000. Kramer' ' estimates compost costs to range
from $7. 00 to $8. 00 per ton of solid waste. Engdahl^10) reported on pilot
studies on composting municipal garbage at San Diego, California. Costs of
operation excluding administration, overhead and capital amortization ranged
from $1.56 per ton where no grinding or other preparation occurred to $20.48
per ton where the garbage was course ground and straw was added. The report
further states that grinding accounted for 30 to 60 percent of the total cost per
ton.
Drobny, etal. (14) reported on the operation of six privately owned
compost operations. Estimates of the capital and operating costs of the sys-
tems have been summarized based on operation of a 25 ton per day pilot plant
in Altoona, Pennsylvania and Houston, Texas. These costs are illustrated
graphically in Figures 3 and 4 for various capacity plants. Operating costs
include payroll, utilities and supplies and administration. The reasons for
the large range of operating costs are not clear.
Composting in Europe was reported by Hart(l?). He found European
refuse more amenable to composting by virtue of its composition. Compost-
ing costs were reported as $2.00 per metric ton or $1.80 per short ton.
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OW
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Experimental Solid Waste Disposal and Recovery Techniques
There are a number of experimental techniques for solid waste process-
ing now in the research and pilot study stages. Most of these processes now
under development are oriented toward the recovery of some economically use-
ful component of solid waste for reprocessing or reuse.
A few of the existing solid waste processes may be modified for recovery
of salvageable materials; however, the economics have not been thoroughly de-
fined at this time. The U.S. Bureau of Mines has been the most active organi-
zation in developing these recovery methods. A Bureau of Mines pilot plant
erected in 1967 has successfully separated metallic iron, non-ferrous metal,
glass and ash tailings from incinerator residues (Davis(18)). The plant has an
operating cost of $2. 00 per ton of residue processed and produces $10 to $12 in
recoverable products per ton of residue, KenahanU9) reports. Drobny, et al.
discusses similar recovery systems applicable to compost operations.
Pyrolysis
Pyrolysis, or destructive distillation, is a process of heating a material
to about 1, 500 degrees F without air to break down the organics into component
parts. The process was originally developed by the U.S. Bureau of Mines for
coal and coke research; however, the process is now finding limited applications
in the solid waste field for the production and recovery of tars, fuel gases and
liquids, alcohols, acetic acid, charcoal ash and other organic chemicals (Sanner,
et al. '^)). Drobny, et al. (*-^i has estimated the net operating costs to be about
$5.70 per ton of refuse; however, because of the retort residence time require-
ment of 23 hours, the process appears unprofitable on a large scale.
Biological Fractionation
Biofractionation involves the processing of organic components of solid
wastes in a manner similar to aerobic digestion to produce a solid residue with
nutrient value for animal feed. The system is highly experimental and costs
now average over $40 per ton of refuse processed (Golueke'-3').
Recycling
The ultimate solution to solid waste disposal problems will be utilization.
Several community groups and some commercial organizations are salvaging
metals, glass, and paper by voluntary sorting the components of solid waste.
To date, the majority of operations recycling municipal refuse have been on a
very limited scale. However, the role of the organizations in acting as a cata-
lyst to bring about changes in attitudes toward waste in general has been of
great value.
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Since the majority of organizations involved in recycling use volunteer
labor, no cost estimates are available. Methods of economically separating
and concentrating urban refuse must be developed before large scale applica-
tions of this method are possible. Central storage areas must be developed
and minimum daily supplies to recovery industries must be insured (Clark'^•"•').
Conversion of solid wastes into only a few marketable products critically limits
the number of markets which can be reached and increases the possibilities of
oversupply. Gentile(^2) stated, "It is important to combine the element of
'separation' and 'salvage' into a complete conversion system in order to develop
a greater variety of by-products and distribute the resultant items and raw mat-
erial to the most diversified markets possible."
Even though the recycling of urban refuse may be uneconomical in itself
at the present time, it may be economically attractive when considering the total
cost to the consumer for producing and discarding a particular product. Not
only are the natural resources used in the production and disposal of a product
utilized, but new natural resources must be developed and utilized to replace
the discarded product. When considering reclamation costs, possible devaluation
of affected lands and decrease in aesthetic value, a net savings may be incurred
from recycling of a majority of urban refuse. A national effort will have to be
exerted, however, before the true economic advantages of recycling can be fully
realized.
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REFERENCES
1. Toftner, R. O. and Clark, R. M. , 1971, Intergovernmental Approaches
to Solid Waste Management: U.S. Environ. Prot. Ag. , Solid Waste Mgt.
Office, Rept. No SW-47ts, 18 p.
2. Kramer, R. J. , 1969, Solid Waste Survey Prepared for Clark County -
Springfield Regional Planning: U.S. Dept. Housing Urban Developm.
Report No. P-239, 78 p.
3. Andres, D. R. and Cope, F. W. , 1970, Solid Waste Transfer and Dis-
posal for Rural Areas: California Vector Views, IT_ (7), 67-76.
4. Cacioppi, J. T. , et al. , 1970, Report of the Governor's Task Force -
Solid Waste Management in Vermont: State of Vermont, 75 p.
5. Golueke, C. G. , 1971, Comprehensive Studies of Solid Waste Manage-
ment: 3rd Ann. Rept. U. S. Environ. Prot. Ag., Solid Waste Mgt. Office,
201 p. also 1st and 2nd Ann. Repts., U.S. Public Health Serv. Publ. No.
2039 (1970), 245 p.
6. Emrich, G. H. and Landon, R. A., 1971, Investigation of the Effects of
Sanitary Landfills in Coal Strip Mines on Ground Water Quality: Pa. Dept.
Environ. Resources, Bur. Water Quality Mgt. Publ. No. 30, 39 p.
7. Ralph Stone and Co. , 1968, Solid Wastes Landfill Stabilization, An Interim
Report: U.S. Dept. Health, Educ., Welf. , Grant No. DO l-UI-00018, 120 p.
8. Sorg, T. J. and Hickman, H. L. , 1970, Sanitary Landfill Facts: U.S.
Public Health Serv. Publ. No. 1792, 30 p.
9. Flower, F. B., 1969, Combustion and Heat: Dept. Environ. Sci. , State
of New Jersey, 15 p.
10. Engdahl, R. B., 1969, Solid Waste Processing, A State-of-the-Art Report
on Unit Operations and Processes: U.S. Public Health Serv. Publ. No.
1856, 72 p.
11. Gilbertson, W. E. and Black, R. J. , 1966, A National Solid Waste Program
is Created: Compost Sci. _6_ (3), 4-7.
12. Michaels, A., 1956, Design Criteria for Municipal Incinerators: Jour. Air
Poll. Control Assoc. _6 (3), 139-43.
13. Greeley, S. A., 1956, Background of Design Criteria for Municipal Incin-
erators - The Designers View: Jour. Air Poll. Control Assoc. 6_ (3),
133-39.
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14. Drobny, N. L. , Hull, H. E. and Testin, R. F. , 1971, Recovery and
Utilization of Municipal Solid Waste: U.S. Environ. Prot. Ag. , Solid
Waste Mgt. Office Publ. No. SW-lOc, 118 p.
15. Rogus, C. A., 1965, Sanitary Fills and Incinerators: American City
£0(3), 114-15.
16. Committee on Refuse Disposal, APWA, 1966, Municipal Refuse Disposal:
Public Administration Service, Chicago.
17. Hart, S. A., 1967, Solid Waste Management in Germany, Report of the
U.S. Solid Waste Team Visit, June 25 - July 8. 1967: U.S. Public Health
Serv. Publ. No. 1812, 18 p.
18. Davis, F. F., 1972, A New Resource Opportunity - Urban Ore: California
Geology 2_5_ (5), 99-112.
19. Kenahan, C. B., 1971, Solid Waste, Resources Out of Place: Environ.
Sci. Tech. _5_ (7), 594-600.
20. Sanner, W. S. , et al., 1970, Conversion of Municipal and Industrial Refuse
into Useful Materials by Pyrolysis: U.S. Bur. Mines Rept. Inv. 7428, 14 p.
21. Clark, T. D. , 1971, Economic Realities of Reclaiming Natural Resources
in Solid Waste: in Inst. Environ. Sci. Ann. Tech. Meet. Proc., Los Angeles,
p. 39-43.
22. Gentile, P., 1964, Resources for the Future and Industrial Conversion: in
Proc., Nat. Conf. Solid Waste Res., Chicago, Dec. 2-4, 1963, Am. Public
Works Assoc., p. 187-90.
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ABANDONED AUTOMOBILE REMOVAL COSTS
TABLE OF CONTENTS
Page No.
Introduction 403
Proposed Federal Legislation 403
Other Abandoned Automobile Recycling Recommendations 404
The Need for a Comprehensive Field Survey 405
Costs of Retrieving Abandoned Automobiles 405
References 407
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ABANDONED AUTOMOBILE REMOVAL COSTS
Introduction
According to the National Industrial Pollution Control Council^ ',
approximately 21% of the automobiles produced in the United States since
1959 are either abandoned or in automobile graveyards. The wide use of
the basic oxygen furnace in the steel industry is the major factor respon-
sible for this accumulation of unused automobile scrap (Dean, et al.* ').
The oxygen furnace is limited to an initial charge of 26 percent scrap com-
pared to 48 percent in the open hearth process. As a result, the market
value of ferrous scrap has decreased proportionately. Although the chief
component by weight of the average automobile is steel and iron (95%),
other metals present in recoverable amounts are lead (1%), copper (1%),
aluminum (1%) and zinc (2%) as reported by the Bureau of Solid Waste Man-
agement'-^ and Dean and Sterner'**),
Besides being a serious waste of natural resources (Shapiro(^)),
unused automobile scrap is responsible for health and safety problems and
environmental degradation (Dean("'). Environmental damage not only occurs
as a result of the physical presence of an unused automobile, but also be-
cause of the increased amount of ore, coal, limestone, and other raw mat-
erials necessary to replace the metals discarded. Even though automobile pro-
duction requires 20 percent of the steel produced and imported by this country
(Javits'''), reprocessed automobile scrap accounts for only nine percent
of total scrap utilized (Ralph Stone and Company(°)).
The recycling of rubber used in automobile production, approxi-
mately 60 percent of the total U.S. production, has presented similar prob-
lems. The primary deterrent to rubber product reuse in the form of auto-
mobile tires has been storage and shipping costs (Hassell(9), Pettigrew and,
Roniger(10)).
Proposed Federal Legislation
Proposed federal legislation that could alleviate future problems
associated with abandoned automobiles and automobile graveyards was
recommended in 1970 by Javits^11) and Gurney(12) in Senate Bills S4204
and S4197 respectively.
Senate Bill 4204 proposes the use of a "disposal deposit" on all new
automobiles. This deposit would be transferrable and refunded at the time
the automobile is deposited at an authorized scrap center. If the car was
illegally abandoned, a public agency or authorized scrap dealer would re-
move the vehicle and collect the disposal fee. This bill is also designed
to decrease the number and size of junk car lots since a dealer would not
receive the disposal deposit until the automobile is actually sent to a re-
processing center. Except for initial organizational expenses, the program
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should be self-financing. This abatement method possibly could be applied to
other items such as tractors, industrial equipment, refrigerators and other
househould appliances.
Senate Bill 4197 proposes financial aid to states and would allot funds
based on motor vehicle registration in the state. The additional revenues
provided to salvage operators in the form of a "bounty payment" would be an
incentive to scrap any unusable automobile.
A similar system is already in operation in Maryland where licensed
scrap processors receives $10 for each car certified as actually reused as
scrap (Leib^-*)). Another method involves collection and accumulation of
abandoned automobiles by municipal agencies with aid of state funds (Karr(14))«
Other Abandoned Automobile Recycling Recommendations
Other recommendations designed to make automobile scrap recycling
economically attractive are:
1. A uniform title clearance procedure which will make abandoned automobile
reprocessing easier.
2. Restrictions on the importation of iron ore and steel to encourage the use
of scrap.
3. Financial incentives to automobile reprocessors in the form of guaranteed
loans and tax write-offs.
4. Manipulation of freight rates to favor scrap reuse.
5. Federally controlled stockpiling of scrap to limit fluctuations in market
demand and scrap availability.
6. Development of recycling districts with reprocessing centers.
7. Elimination of "built in" obsolescence in the automobile industry.
8. Development of more efficient methods of nonmetallic waste separation in
abandoned automobile reprocessing.
9. Acceleration and expansion of research devoted to the increased use of
automobile scrap.
10. Initiation of legislation prohibiting abandonment of vehicles and restrictions
on ownership of wrecked, nonoperating or discarded vehicles as outlined
in the "Model Ordinance" prepared by the National Institute of Municipal
Law Officers(15).
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The Need for a Comprehensive Field Survey
A comprehensive field survey is necessary to insure the success of an
abandoned vehicle collection program. Information from such a survey should
include type of automobile, general condition, amount of surrounding rubble,
and if possible, the owner of the land on which the vehicle is located. Location
is probably best facilitated by assigning the vehicle a number and marking it
on an appropriate map.
Many surveys have been performed utilizing community service organi-
zations such as the Boy Scouts of America, YMCA and other groups. Some-
times local and state agencies can be utilized in the compilation of abandoned
automobile data. West Virginia used the state police to locate and obtain re-
lease of discarded vehicles. In some communities, it may be possible to have
"phone-in" campaigns such as in Michigan where citizens were informed of the
program through the local news media as reported by General Motors Corpor-
ation!16).
ChaseV !7) mentioned a bounty system where students were given a $1
reward for each automobile reported and accompanied by a certificate of re-
lease. Some commonly accepted title clearance procedures must be developed
before a program such as this could be applied on a large scale. Another pos-
sible method that may be economically feasible in locating abandoned automo-
biles is aerial reconnaissance. Two people is all that is necessary to complete
such a survey and large areas can be viewed in a relatively short period of time.
Cost of Retrieving Abandoned Automobiles
After an adequate survey has been prepared and certificate of release or
title clearance is accomplished, actual removal of discarded vehicles will be
possible. In the West Virginia program, the National Guard were used to re-
trieve vehicles. Reported costs were $40 per automobile, but it was estimated
this cost would be 50 percent less if the program was conducted when weather
conditions were more favorable (Gandee' ').
In a cleanup campaign in Columbia County, New York, the County Health
Department collected 12, 000 automobiles at a unit cost of $1.67. In programs
conducted by the Vermont Motor Vehicle Department 13, 151 vehicles were col-
lected at an average cost of $10 per car. Both projects used trucks to pick up
vehicles. Automobiles were deposited in a central collection area where sal-
vage operators disposed of the accumulated scrap.
Steen' ') reported that the Tennessee Valley Authority has developed a
feasible method of collecting derelict vehicles in rural areas. The focal point
of this method according to Steen'^0) is the use of a modified truck which re-
quire only one man to pick up, deliver, and deposit a vehicle with or without
wheels. A summary of the results of this program based on available infor-
mation is as follows:
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Location
Anderson Co., N.C.
LoudonCo., Tenn.
Towns Co. , Georgia
Murphy, N. C.
TOTALS
Number of
Automobiles
Total Expenditures Unit Cost
1,577
$4,183.59
450.00
1,450.00
736.36
$6,819.95
$4.32
The average reported unit cost of $4.32 per vehicle compares favor-
able with the estimate of $4. 50 made by the TVA during initial stages of the
program.
Little data exists concerning the cost of vehicle retrieval labor, im-
poundment, and subcontractor cost breakdown. Rothman(^) estimates the
total cost of disposing of abandoned automobiles in New York City is $40 to
$60 per vehicle. In areas where impoundment is not necessary, automobiles
may be removed by licensed processors free of charge.
Better cost estimates will be possible when a standard format is de-
veloped for reporting results of an abandoned automobile removal program.
The information form should include descriptions of:
1. Field Survey Methods
2. Advertisement Methods
3. Removal Techniques (including equipment, average haul distance, con-
dition of abandoned automobiles, source of labor and other pertinent
factors)
4. Storage Facilities
5. Final Disposition of Scrap
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REFERENCES
1. National Industrial Pollution Control Council, 1970, Junk Car Disposal:
U.S. Dept. Comm. , 54 p.
2. Dean, K. C. , Chindgren, C. J. and Valdez, E. G. , 1972, Innovations
in Recycling Automobile Scrap: U.S. Bur. Mines, 1Z p.
3. Bureau of Solid Waste Management, 1970, The Automobile Cycle: An
Environmental and Resource Reclamation Problem: Publ. No. SW-80,
46 p.
4. Dean, K. C. and Sterner, J. W. , 1969! Dismantling a Typical Junk
Automobile to Produce Quality Scrap: U.S. Bur. Mines Rept. Inv. 7350,
17 p.
5. Shapiro, I. D., 1964, The Scrap Processor's Role in Auto Salvage: Proc.
Nat. Conf. Auto Salvage Inst. of Scrap Iron and Steel, p. Dl-6
6. Dean, K. C., 1967, Bureau of Mines Research for Utilizing Automobile
Scrap: Hearings before the Committe on Public Works, U.S. Senate,
416 p.
7. Javits, J. K. , 1970, Disposal of Junked and Abandoned Motor Vehicles:
Hearings of the Subcommittee on Air and Water Pollution before the
Committee on Public Works, U.S. Senate, 416 p.
8. Ralph Stone and Company, 1969, Copper Content in Vehicular Scrap:
U.S. Bur. Mines, 43 p.
9. Hassell, E. W. , 1970, The Automobile Wrecking/Dismantling Industry:
U.S. Dept. Comm., Office Business Programs, 93 p.
10. Pettigrew, R. J. and Roninger, R. H. , 1971, Rubber Reuse and Solid
Waste Management, Part I: U.S. Environ. Prot, Ag. , Solid Waste Mgt.
Office Publ. No. SW-ZZC, 1ZO p.
11. Javits, J. K. , 1970, The Motor Vehicle Disposal Act: U.S. Senate Bill
S4204
12. Gurney, E. J. , 1970, The Motor Vehicle Disposal Assistance Act: U.S.
Senate Bill S4197
13. Leib, P., 1971, Junk Cars - Mines of Valuable Metal: Appalachia _5 (2),
1-13
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14. Karr, R. K. , 1972, Vermont Shows the Way with Junk Vehicle Program.;
Public Works 103 (5), 104-5
15. National Institute of Municipal Law Officers, 1967, Model Ordinance on
Abandoned, Wrecked, Dismantled or Discarded Vehicles; Wash., B.C.,
4 p.
16. General Motors Corporation, 1971, How to Harvest Abandoned Cars;
Detroit, 19 p.
17. Chase, P., 1972, Personal Communication; Michigan Dept. of Corrections
18. Gandee, J. , 1972, Personal Communication: West Virginia Dept. of High-
ways
19. Steen, R. J., 1972, Try a Tilt-Bed Truck to Solve the Junk Car Problem;
American City 87_ (3), 123-27
20. Steen, R. J, , 1972, Personal Communication: Tennessee Valley Authority,
Knoxville, Tennessee-
21. Rothman, N. , 1972, Personal Communication: New York Dept. of Sani-
tation
22. Management Technology, Inc., 1970. Automobile Scrapping Processes
and Needs for Maryland; U.S. Public Health Serv. Publ. No. 2027, 64 p.
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EROSION AND SEDIMENTATION CONTROL COSTS
TABLE OF CONTENTS
Page No.
Introduction 411
Prevention and Control of Erosion and Sedimentation 412
Cost of Erosion and Sediment Control Structures 414
References 417
LIST OF TABLES
1. Variables Affecting Erosion and Sediment Control Costs 415
2. Summary of Sediment Collection Facility Construction Costs 416
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EROSION AND SEDIMENTATION CONTROL COSTS
Introduction
Sediment is the greatest single pollutant of streams, lakes, ponds and
reservoirs. Sediment lowers the quality of water for municipal and industrial
uses and for boating, fishing, swimming, and other water based recreation; it
increases the wear on equipment, such as turbines, pumps and sprinkler irri-
gation systems. Sediment carries with it pesticides, phosphates and other
chemical pollutants(1).
Each year more than a million acres of land in the United States are con-
verted from agricultural use to urban use. Studies show that erosion on land
going into use for highways, houses, shopping centers and other commercial
or residential uses is about 10 times greater than on land in cultivated row crops,
200 times greater than on land in pasture and 2, 000 times greater than on land
in timber. The nationwide damage caused annually by sediment has been esti-
mated at more than $500 million. Much sediment comes from agricultural land,
but the amount contributed by land undergoing urban development is high in pro-
portion to the acreage(l).
Severe sediment problems occur when covering vegetation is removed
in construction areas, when the flow regime in channels is altered by realign-
ment or by increased or decreased flow, or when fill, buildings, or bridges
obstruct the natural flowway(^). Sediment movement and deposition are part
of the natural environment, but the average sediment yield from the landscape
and the condition of stream channels tend to change with the advancing forms
of man's land-use activity. A major problem is that the scientist or engineer,
because of his relatively narrow field of investigation, cannot always completely
envision the less desirable effects of his work and communicate alternative sol-
utions to the public(2). Recent publications, Powell, et al. (3), West Virginia
Department of Natural Resources^), Pennsylvania Department of Environmental
Resources(5), and Soil Conservation Service^/ indicate that governmental ag-
encies are becoming very much concerned with damages caused to the environ-
ment by erosion and sedimentation.
Urbanization tends to increase both the flood volume and the flood peak
as pointed out by Leopold(^) in his study summarizing existing knowledge of the
effects of urbanization on hydrologic factors. Much of the erosion occurs during
the construction period, but areas below a construction site may erode more
after construction is completed because of the rapid runoff from impervious
pavement, parking lots, or compacted soil. Increased runoff erodes stream
banks and channels and causes flooding below the construction site.
Surface mining activities are responsible for serious erosion and sedi-
mentation problems in some areas because of the highly erodable nature of
spoil banks(^) and the usual sparseness of vegetation as compared to "undis-
turbed" areas(8). In other areas, timbering operations, with attendant logging
and haul roads and removal of a forest canopy which causes increased runoff,
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can be the most damaging environmental problem, particularly downstream of
the operation. The major source of sedimentation pollution in some areas is
the "right-of-way" for a powerline, pipeline or other utility.
Prevention and Control of Erosion and Sedimentation
As with most stream pollutants, sediment can best be prevented at the
source, i.e. , control erosion and runoff at or near the area undergoing urbani-
zation, deforestation or surface mining. Temporary or emergency "back-up"
precautions can be employed using sedimentation and storage collection struc-
tures. The structures must be designed to insure there is no danger of failure
which could cause downstream damage. On large projects, a comprehensive
survey must be performed to evaluate geologic, hydrologic and engineering
design considerations. This survey is necessary to insure that the structure
will provide adequate sediment and storage capacity and be of safe design.
Since urbanization and other land uses tend to increase flood volume
and the flood peak, provision for flood storage upstream will decrease flood
peaks and sedimentation yield and compensate for the increased flow caused
by land use. Reservoir storage installed on a river reduces the magnitude of
peak discharge by spreading the flow over a longer time period. Channels
themselves provide temporary storage and act as if they were small reser-
voirs. Overbank flooding on the flat flood plain is a way that natural rivers
provide temporary storage and thus decrease flood peaks downstream.
Flood storage for urban areas can take many forms including the fol-
lowing(°):
1. Drop inlet boxes at street gutter inlets.
2. Street-side swales instead of paved gutters and curbs.
3. Check dams, ungated, built in headwater swales.
4. Storage volumes in basements of large buildings receiving water from
roofs or gutters and emptying into natural streams or swales.
5. Off channel storage volumes such as artificial ponds, fountains or tanks.
6. Small reservoirs in stream channels such as those built for farm ponds.
The following factors determine the amount of erosion that occurs in
an area:
1. Soil types
2. Slope of the terrain
3. Rainfall intensity
4. Infiltration capacity of the soils
5. Amount and kind of vegetation
6. Construction methods
-412-
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Erosion and sedimentation can be controlled effectively, and at reason-
able cost, if certain principles are followed in the use and treatment of land.
1. Know the soil characteristics, geology, hydrology and topography of the
area. Information on soils can be found in the Soil Conservation Service
(SCS) soil survey report of the area. If there is no report, information
may be available in the "open files" of the SCS District Office or the Agri-
cultural Extension Service. Soil surveys describe the characteristics and
properties of each kind of soil in the area - its texture, slope, depth,
erodibility, permeability, degree of wetness, presence of impervious or
porous layers and other information useful in construction. The soils
information found in these reports, though very useful for an understanding
of soils problems, is general in nature. It does not replace the need for
professional assistance in the design of structures where failure would
cause loss of life and property damage.
2. Have a site development plan that includes provisions for control of run-
off, erosion and sedimentation and reclamation of areas disturbed by the
land use.
3. Do not grade or strip more land than needed for immediate use. In this
way, soil is left bare for the shortest period of time. This calls for de-
veloping large tracts in small workable units. In the case of strip mining
and timbering operations, reclamation of disturbed areas should be per-
formed concurrently with development.
4. In construction projects, keep grading at a minimum and remove only un-
desirable trees wherever possible. Protect critical areas with mulch or
temporary cover crops and with mechanical methods such as diversions
and prepared outlets.
5. Reduce velocity and control the flow of runoff by detaining runoff on the
site to trap sediment by constructing sediment basins. Consideration
should be given to offsite measures that may be needed to prevent dam-
age to downstream land and property by either erosion or sediment.
6. During construction use soils that are suitable to the development.
7. Establish permanent vegetation and install erosion control structures as
soon as possible.
-413-
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Cost of Erosion and Sediment Control Structures
Normally no two erosion or sediment control structures are alike.
Each facility has to be individually designed to suit site conditions and to
satisfy hydrological requirements. Therefore, no standard cost estimate
per unit of watershed or other commonly accepted method of basing cost on
unit area is practical without first considering site conditions and hydrologi-
cal requirements. Some of the variables that affect construction costs for
these structures are presented in Table 1.
Most of the reported costs for erosion and sediment control in Penn-
sylvania and West Virginia were for structures constructed in conjunction
with highway projects. These structures are usually designed for a limited
life and require frequent dredging or cleaning out to maintain operating
efficiency. The unit cost estimates reported by the highway departments are
presented in Table 2. The design of these structures conforms to design re-
quirements given in publications by West Virginia Department of Natural
Resources^), Soil Conservation Serviced) and Pennsylvania Department of
Forests and Waters(l°).
On small projects, the largest cost may be mobilization of equipment.
It may, therefore, be advantageous to perform reclamation on a watershed
basis so as to reduce individual mobilization costs and possibly the number
of structures required.
-414-
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TABLE 1
VARIABLES AFFECTING EROSION AND SEDIMENT CONTROL COSTS
I. Type of Installation
A. Dams - Embankment, rpckfill, concrete, log and pole/brush or
other type of dam structure
B. Ponds - Excavated, natural or embankment
C, Diversions - Channel, ditch or other methods
D. Riprap for slope, shore or channel protection
E. Other types of installations
2. Size of Installation Required
3. Hydrological Requirements - Design Flood
4. Design Life of Installation
5. Site Preparation
A. Access roads
B. Clearing and grubbing
C. Water diversion and dewatering
D. Other site preparation requirements
6. Availability and Haul Distances for Construction Materials
7. Building Code Specifications, Inspection Fees, Performance Bond
Requirements and Legal Requirements
8. Post Construction Reclamation
-415-
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TABLE 2
SUMMARY OF SEDIMENT COLLECTION FACILITY CONSTRUCTION COSTS
Structure Type Unit Cost
Excavated Dams or Ponds C.Y. $7 - $8
Embankment Dams C.Y. $4 - $6
Stone Check Dams Ft.2 $10 - $30
Log and Pole/Brush Dams Dam $150
Riprap
Dumped C.Y. $5.50 -$6.75
Placed C.Y. $12 - $16
Diversion Ditches (2' Deep x 6' Wide) L.F. $l-$2.75
Sand Bags Bag $2.50
Maintenance
Sediment Dredging C.Y. $5 - $7
Hauling .... First Mile C.Y. $.55 -$.70
.... Each Additional Mile C.Y. $.20-$. 25
-416-
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REFERENCES
1. Soil Conservation Service, 1970, Controlling Erosion on Construction
Sites: Agriculture Information Bull. 347, 32 p.
2. Guy, Harold P. , 1970, Sediment Problems in Urban Areas: U.S. Geol.
Survey Circ. 601-E, 8 p.
3. Powell, M. D., Winter, W. C. and Bodwitch, W. P., 1970, Community
Action Guidebook for Soil Erosion and Sediment Control: Nat. Assoc.
Counties Res. Foundation, Wash., D. C. , 64 p.
4. West Virginia Department of Natural Resources, 1972, Drainage Handbook
for Surface Mining; Div. Reclamation, prepared by Div. Planning and
Development in cooperation with Soil Conservation Service, 65 p.
5. Pennsylvania Department of Environmental Resources, 1972, Implemen-
tation Plan and Regulations Dealing With Erosion and Sedimentation Con-
trol: Adopted by the Environmental Quality Board, September 21, 1972,
7 p.
6. Leopold, Luna B. , 1968, Hydrology for Urban Land Planning - A Guidebook
on the Hydrologic Effects of Urban Land Use: U.S. Geol. Surv. Circ. 554,
18 p.
7. Adams, L. M. , Capp, J. P. and Eisentrout, E. , 1971, Reclamation of
Acidic Coal - Mine Spoil with Fly Ash: U. S. Bur. Mines Rept. Inv. 7504,
29 p.
8. Bramble, W. C. and Ashley, R. H. , 1955, Natural Revegetation of Spoil
Banks in Central Pennsylvania: Ecology _36.(3), p. 417-23.
9. Soil Conservation Service, 1969, Engineering Standard - Debris Basin:
Technical Guide No. 350, 11 p.
10. Pennsylvania Department of Forest and Waters, 1968, Bridges. Walls,
Fills, Channel Changes. Etc.: Water and Power Resources Board,
Form FWWR-23, 23 p.
-417-
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INDUSTRIAL WASTES "ORPHAN" AND OTHER
ENVIRONMENTAL PROBLEMS IN THE PUBLIC SECTOR
TABLE OF CONTENTS
Page No.
Introduction 421
Types of Solid Wastes 421
Cost Analysis and Methods of Disposal 422
References 425
LIST OF TABLES
1. Ash Collection and Utilization in the United States - 1971 423
-419-
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INDUSTRIAL WASTES "ORPHAN" AND OTHER
ENVIRONMENTAL PROBLEMS IN THE PUBLIC SECTOR
Introduction
This section is concerned with accumulations of solid wastes other than
municipal, abandoned automobiles, and earth materials from the coal mining
industry. Further, the solid wastes are abandoned and are now a public re-
sponsibility; they may be more a public nuisance than a source of air or water
pollution; and one can reasonably expect to find these wastes in the Monongahela
River Basin. The solid waste accumulations are from manufacturing, mining,
timbering, transportation and other abandoned activities of man in the Monon-
gahela River Basin.
Many of the wastes have littered the landscape and stream beds for
a long period of time, a hundred years or more, although, the volume of solid
waste has increased rapidly in the last 50 years. The solid wastes fall into
three main categories of materials:
1. Materials of metal manufacture which can be classified as scrap metal.
2. Wood product materials including timbering and manufacture.
3. Soil and rock type materials including brick, coke breeze, fly ash, slag
and other materials resulting from production and manufacture.
Types of Solid Wastes
Other than coal mine refuse, abandoned automobiles and municipal
wastes, there is very little information on the types, characteristics and
quantities of abandoned industrial and other solid wastes that can be found in
the Monongahela River Basin. The following list is based on a knowledge of
the history of industrial development within the area and, for each industry or
activity the type or solid wastes that can be expected are given.
1. Coke Making Industry - Coke breeze, beehive ovens, abandoned buildings,
track and other metal equipment associated with coke manufacture.
2. Coal Fired Power Plants - Fly ash, bottom ash, boiler slag, abandoned
buildings and metal plant equipment.
3. Coal Processing Plants and Other Mining Equipment - Tipples, hoists,
engines, pumps, track, mine cars, scales, abandoned buildings and other
wood and metal equipment.
4. Railroad Industry - Abandoned track, ties, signalling equipment, water
towers, bridges and other wood and metal equipment.
5. Glass Industry - Slag, cullet, buildings and equipment.
-421-
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6. Pottery and Stoneware Manufacture - Broken crockery, refractories,
platermolds, abandoned buildings and equipment.
7. Brick Manufacture - Broken brick, molds, ovens, plant and equipment.
8. Foundries - Stone furnaces, refractories, waste products and metal
working equipment.
9. Chemical Industry - Plant wastes, abandoned buildings and equipment.
10. Forest Products Industry - Slashings and bark from timbering operations,
and sawdust, sawmill slabs and scrap wood from sawmill operations.
11. Petroleum Industry - Abandoned pumps, feeder lines, pipe, derricks
and other equipment from oil and gas production. Wastes, trash, spent
catalysts, scrap lumber and dense sludges from refinery operations.
12. River Navigation - Abandoned piers, wharfs, buildings, barges, boats
• and other wood and metal equipment.
13. Metal Smelting and Refining - Slag, obsolete or abandoned plant and equip-
ment, residues from refining iron, lead, zinc, aluminum and other metals.
14. Demolition Contractors - Refuse, concrete, brick, lumber and scrap
metal usually in piles.
Cost Analysis and Methods of Disposal
An in depth survey has not been made on location and quantities of solid
wastes discussed in this section, but it appears, that for many of these wastes,
the methods of disposal and costs discussed in the section "Solid Wastes Hand-
ling and Disposal Costs" could be used for estimating purposes.
Most of the scrap metal would be iron and steel and could have salvage
value, the value depending on tonnage and size of pieces at a specific location.
Scrap metal dealers may be willing to salvage this material if permission is
granted by property owners.
There is no information on abandoned chemical wastes in the Monon-
gahela River Basin. It may be hazardous to disturb chemical wastes and each
occurrance of this type material will have to be investigated prior to disposal
to prevent water pollution and handling problems.
Fly ash, bottom ash and boiler slag does have limited use and old dis-
posal areas are being worked for construction materials and other uses. Table
1 based on a publication by Sikes and Kolbeck^) tabulates ash collection and
utilization in the United States in 1971. The percent of ash utilization has risen
from 12. 1 in 1966 to 20. 1 in 1971.
-422-
-------
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-423-
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Disposal of much of the solid waste can best be handled at the local
level. A community action program designed to clean up the local environ-
ment would remove many of these public nuisances. If approached, scrap
dealers and property owners may be more than willing to cooperate in dis-
posing of solid wastes littering the landscape. Clean up programs similar
to those initiated for removal of abandoned automobiles may be effective.
Most of the solid wastes are not sources of air and water pollution, there-
fore, the part played by the Appalachian Regional Commission should be to
encourage community action programs.
-424-
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REFERENCES
1. Sikes, P. G. and Kilbeck, H. J. , 1972, Disposal and Utilization of Power
Plant Ash in a Metropolitan Environment: Am. Soc. Civil Eng. Ann. and
Nat. Environ. Eng. Meet., Oct. 16-22, Meeting Preprint 1849, 30 p.
2. Gibbs & Hill, 1972, Preliminary Tabulation of Collected Data: prepared
for Appalachian Regional Commission as part of study "Development of
an Overall Economic /Environmental Plan for the Monongahela River
Basin"
-425-
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ADDENDUM
-427-
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ADDENDUM
TABLE OF CONTENTS
Page No.
Air Pollution Control and Wastewater Treatment 431
Erosion and Sedimentation Control 433
Strip Mine and Refuse Bank Reclamation 434
References 436
-429-
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-------
ADDENDUM
Air Pollution Control and Wastewater Treatment
Because of increasingly stringent SO2 emission regulations and a limited
reserve of low cost, low sulfur fuels, a SOX removal process operated in an
efficient and economic manner is urgently needed. A new process designed to
control atmospheric pollution in industries with the recovery of useful products
has been developed by Lin(l) in the laboratory.
The new SO removal system is described briefly as follows:
The combustion gases from the furnace containing SC>2i SO^ and suspend-
ed solid particles are passed through a dust collector for removal of fly ash.
The flue gas containing SO is then passed.through a catalytic oxidation converter
X
to oxidize SO2 into 803. The flue gas then goes to a lime reactor where lime is
purposely fed in excess of the amount required for complete conversion of 803 to
CaSO4. Since the flue gas from the catalytic oxidation converter contains mois-
ture, the following reactions take place:
S03 (g) + H20 (g) ^H2S04 (g)
H2S04 (g) + CaO (s) ^CaS04 (s) + H2O (g)
803 is a very reactive gas and may also combine directly with CaO to
form CaSO4:
SO3 (g) + CaO (s) 5==CaSO4 (s)
Dust particles in the gas discharged from the lime reactor are further
separated by a dust collector and the effluent will be substantially free from dust
and SOX. Nearly 100 percent SO3removal has been achieved in the laboratory.
The reacted lime particles are discharged from the lime reactor into a powder
processing unit. After treatment, a new product is released from the unit which
has been named "Linfans. "
The important feature of this process is that the reactions in the lime
reactor are between gaseous and solid reactants, accompanied by a molecular
diffusion in the solid reactant. Since the reactant (CaO) added to the system is
in a solid form, the rate of application needed may not be high and can easily
be controlled.
Laboratory investigation has shown the solid product, Linfans, contain-
ing anhydrous CaSO4 and unspent lime has the following uses:
1. It can be combined with fly ash for production of construction materials.
2. Used for flooring plaster and hard finish plaster.
-431-
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3. Used in wastewater treatment for acid neutralization and for phosphate
and turbidity removal.
A series of laboratory experiments were performed to compare Lin-
fans produced from different SOX removal systems with high calcium lime in
regard to sludge volume produced in neutralization of acid solutions. The
tests were conducted on one percent (1%) by volume sulfuric acid solutions.
In all cases, Linfans produced the least sludge volume. The percentage of
sludge volume produced from neutralization was dependent on the percent of
unspent lime in Linfans. The percent of unspent lime should be neither ex-
tremely high or low.
The sludges from neutralization of acid solutions by high calcium lime
have poor compaction characteristics which are attributed to the typical acic-
ular shape of the crystals that are formed. By contrast, the CaSC>4 crystals
from neutralization by unspent lime in Linfans are in rhombic form. It is
believed the insoluble anhydrous CaSC^ in Linfans serves as nuclei for accel-
erated growth of CaSO^ particles. This results in higher settling velocities,
a considerable reduction in sludge volume and a shorter retention time in a
sedimentation tank. Therefore, it is indicated that sludge handling and dis-
posal problems can be greatly minimized if Linfans is used.
It must be emphasized the information given in the publication by Lin(l)
indicates a limited amount of laboratory testing has been performed. It appears
a great deal more laboratory testing will have to be accomplished before pilot
studies can be considered.
Linfans possibly can be used in treatment of wastewater from pickling
processes used in basic steel making, metal working and plating. It is not
known whether Linfans would be suitable for treatment of acid mine drainage.
The laboratory experiments were performed using strong sulfuric acid solu-
tions (over 18, 000 mg/1 of H^SO,^) and there were no interfering metallic ions.
This sulfate concentration exceeds that of most mine drainage discharges.
Calcium sulfate (CaSO4) is not normally a precipitate in sludge from mine
drainage treatment because sulfate ions are removed only when the solubility
product of calcium sulfate is reached (about ZOOO mg/1 CaSO^). It appears
Linfans would add additional hardness to the mine drainage effluent and cause
gypsum scale on plant equipment and possibly in the effluent. The possibility
of seeding high sulfate mine drainage to promote larger crystal growth and
therefore dense sludge should be investigated.
Quicklime (CaO) does not react rapidly and efficiently with acids to
neutralize them. It must first hydrate (convert to Ca(OH)2) before it reacts
readily and efficiently. There are hazards connected with the use of quick-
lime. It is a very caustic irritant to human skin, eyes and mucuous mem-
branes. A quantity of quicklime suddenly dumped into an influent can cause
a steam explosion.
-432-
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Erosion and Sedimentation Control
Two recent publications, one by Thronson(2) and the other by Becker
and Mills(3) contain a wealth of information on erosion and sedimentation con-
trol.
Thronson comes to the conclusion the cost of effective erosion and sedi-
ment control is probably minimal and that the principal problem lies in achiev-
ing effective administrative control and enforcement by concerned agencies
involved in erosion and sediment control programs. It is extremely difficult
to obtain reliable information regarding the cost of temporary erosion and
sediment control used only during construction. Normally the costs are hidden
in unit costs for excavation and compaction, pipe and other equipment. It is
difficult to define the temporary and permanent portion of a facility. Tempor-
ary erosion and sediment control for highways with average construction costs
of $1, 000, 000 per mile were estimated at $10, 000 to $15, 000 per mile. The
cost for control in housing developments was given as $40 per lot by engineer-
ing and geologic consultants and $100 per lot by developers.
A basin-wide task force, which includes representatives from all con-
cerned organizations within the basin, probably has the best chance of develop-
ing and carrying out a successful control program. Trained manpower can be
made available by utilizing specific qualified personnel such as geologists,
hydrologists, agronomists, engineers, planners, lawyers and managers from
the various participating groups within the task force. The crucial element of
a sedimentation control program is the enforcement of adopted standards.
The publication by Becker and Mills presents a comprehensive approach
to the problem of erosion and sediment control from beginning of project plan-
ning to completion of construction. The "Guidelines" is designed and intended
for use by both technical and lay personnel. It provides:
1. A description of how a preliminary site evaluation determines what poten-
tial sediment and erosion control problems exist at a site being considered
for development.
2. Guidance for the planning of an effective sediment and erosion control
plan.
3. Procedures for the implementation of that plan during operations.
Technical information on 42 sediment and erosion control products,
practices, and techniques is contained in four appendices.
-433-
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Strip Mine and Refuse Bank Reclamation
Heine and Nickeson(4) recommend the use of substantially increased
quantities of limestone in reclaiming old strip mines in alkalinity-poor water-
sheds. The cost of limestone is essentially defrayed by limiting backfilling
to the degree necessary to improve surface runoff and reduce erosion.
Studies have shown there is less probability of success in backfilling
and planting old strip mines than in reclamation of current active operations.
This is principally due to the mixture of acid materials and tops oil in the spoil.
The problem is further complicated by the stony nature of old spoils. Spoil
segregation and burial of acid materials are no longer possible and there are
no concentrations of "soil type" material. The stony material forming the top
layer after reclamation of an old strip mine will be of the same general chemi-
cal composition as the old surface and be as permeable (to both air and water)
as it was prior to grading. Since there is little soil type material in the top
layer, it is difficult to establish a dense ground cover. Trees are the only
vegetation that can be readily established and they do not rapidly form a soil
profile. The surface of many reforested strip mines planted with trees as
long as 30 years ago are almost as stony as the surface of a new unreclaimed
strip mine.
Many old strip mines have developed excellent tree growths on some
portions of the disturbed areas while other portions remain "hot" and devoid
of vegetation. An important practical advantage to "limestone reclamation"
is that areas with well established tree growth can be left undisturbed except
for application of lime, fertilizer and seed to accelerate vegetation growth.
In the Alder Run and Muddy Run watersheds, Clearfield County, Penn-
sylvania, Heine and Nickeson recommended the use of quarry limestone (Class
2RC). It is an aggregate of particle sizes ranging from dust to 3/4 inch. They
recommend an average layer of one inch thickness be spread over the entire
strip mine (approximately 200 tons per acre). In practice the limestone will
not be evenly distributed, but will be spread thicker in areas of thick spoil and
maximum recharge. The limestone is spread at the completion of grading and
disked into the top layer of the spoil.
The presence of this relatively fine grained material will decrease the
stoniness of the top layer, making it more acceptable for grass growth. The
top layer will be alkaline for many years, allowing grasses to become well
established and a soil profile to develop.
The cost of quarry limestone (Class 2RC) was given as $1. 15 per ton
by bulk, $2.80 delivered, for the Alder Run and Muddy Run projects.
The U. S. Bureau of Mines(^» °) has demonstrated the use of fly ash in
strip mine and refuse bank reclamation. The addition of large quantities of fly
ash (150 to 800 tons per acre) will not only dilute the surface materials and
-434-
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neutralize acids, but produce physical changes in the material that will en-
hance plant survival and growth. The bulk density of the mixture is decreased,
thereby increasing pore volume, moisture availability, and air capacity, hence
improving conditions for root penetration and growth.
Fly ash resembles soil in certain physical and chemical properties and
it is mostly in the silt size range. Beside often being alkaline, it contains plant
nutrients and possesses moisture-retaining and soil conditioning capabilities.
Analyses indicate fly ash contains many trace elements essential to plant growth.
The use of fly ash in reclamation of strip mine and refuse banks helps
solve the fly ash disposal problem. According to Sikes and Kolbeckl') more
than 27, 000, 000 tons of fly ash were produced in 1971 by power plants and less
than 12 percent was utilized. Fly ash can be obtained from power plants at no
cost in many areas. The only costs attributed to using fly ash would be hauling
the fly ash from the power plant site to the reclamation area and those associ-
ated with spreading and disking.
-435-
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REFERENCES
1. Lin, Ping-Wha, 1972, Air Pollution Control and Wastewater Treatment
in One Unique Process: ASCE Ann. and Nat. Environ. Eng. Meet. ,
Oct. 16-22, Preprint 1786, 23 p.
2. Thronson, R. E. , 1972, Control of Erosion and Sediment Deposition from
Construction of Highways and Land Development: U.S. Environmental
Protection Agency, Office of Water Programs, 50 p.
3. Becker, B. C. and Mills, T. R. , 1972, Guidelines for Erosion and Sedi-
ment Control Planning and Implementation: U.S. Environmental Protec-
tion Agency, Office of Research and Monitoring, EPA-R2-72-015, prepared
by Hittman Assoc. , Inc. for Maryland Department of Water Resources, 228 p.
4. Heine, W. N. and Nickeson, T. L. , 1971, Concept Paper on the Proposed
Use of Limestone in Strip Mine Reclamation: p. 227-36 in Skelly and Loy,
Muddy Run Mine Drainage Pollution Abatement Project, Operation Scarlift
SL 155: Rept. to Pa. Dept. Environ. Resources, 239 p.
5. Adams, L. M. , Capp, J. P. and Gillmore, D. W. , 1972, Coal Mine Spoil
and Refuse Bank Reclamation with Powerplant Fly Ash: Third Mineral
Waste Utilization Symposium, March 14-16, Chicago, 7 p.
6. Adams, L. M. , Capp, J. P. and Eisentrout, E. , 1971, Reclamation of
Acidic Coal-Mine Spoil with Fly Ash: U.S. Bur. Mines Rept. Inv. 7504,
29 p.
7. Sikes, P. G. and Kolbeck, H. J. , 1972, Disposal and Utilization of Power
Plant Ash in a Metropolitan Environment: ASCE Ann. and Nat. Environ.
Eng. Meet., Oct. 16-22, Preprint 1849, 30 p.
-436-
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ACKNOWLEDGMENTS
The purpose of this publication is to provide data •which will enable the
Appalachian Regional Commission to estimate costs of pollution abatement
in the Monongahela River Basin. In order to perform this function, the
Appalachian Regional Commission needed an effective, workable handbook on
pollution control costs and factors effecting these costs.
This study was performed by Michael Baker, Jr., Inc., for the Appalachian
Regional Commission under ARC Contract No. 72-87/RPC-713 titled "Analysis
of Pollution Control Costs." Support came from the U.S. Environmental
Protection Agency under Grant 1^010 HQC.
The cooperation of many individuals in government and in private industry
in supplying information used in the study is gratefully acknowledged.
Special credit must be given to James F. Boyer and Virginia E. Gleason of
Bituminous Coal Research, Inc.; Ronald D. Hill and Elmore C. Grim of the
U.S. Environmental Protection Agency; Clifford H. McConnell, Fred S. Oldham,
Alexander E. Molinski, Michael D. Yaccino, Willis R. Devens, Robert Buhrman
and Donald Fowler of the Pennsylvania Department of Environmental Resources;
Dr. H. B. Charmbury and Dr. Harold L. Lovell of Pennsylvania State University;
Benjamin C. Green of the West Virginia Department of Natural Resources;
Malcolm 0. Magnuson, Edward A. Mihok and Robert J. Evans of the U.S. Bureau
of Mines: Dr. Gerald L. Barthauer and Jerry L. Lombardo of Consolidation
Coal Co., Herbert E. Steinman of Jones £ Laughlin Steel Corp.; John C. Draper
of Duquesne Light Co.; John W. Foreman of Gwin, Dobson and Foreman, Inc.;
Franklin H. Mohney of Pennsylvania Coal Mining Association; and Stephen
McCann of Western Pennsylvania Coal Operators Association.
The study was performed by the Geotechnical Engineering Department and
Bionomics Studies Group of Michael Baker, Jr., Inc.
4U.S. GOVERNMENT PRINTING OFFICE: 1974 546-317/32Z 1-3 14-37
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SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
1, Report No.
w
S. Report Daw Feb. , 197^
6.
8, Performing Organization
BAKER-ARK- 73-04
Analysis of Pollution Control Costs
Frank J. Doyle, Harasiddhiprasad G. Bhatt,
and John R. Rapp
Michael Baker, Jr. , Inc.
4301 Dutch Ridge Road
Beaver, Pennsylvania 15009
12. sp-y -w<,g organisation Appalachian Regional Conwaitsion and U.S.
-.._,' -i •<- Environmental Protection Agency Report
Number EPA-6?0/2-7^-009, February
1^010 HQC
72-87/RPC-713
, ;.•„ df Report su
Proteebion
Agency
In August, 1971, the Environmental Protection Agency convened the Mononga-
hela Enforcement Conference in Pittsburgh, Pennsylvania. At this meeting the
Appalachian Regional Commission was assigned the task of developing a comprehen-
sive environmental improvement program for the Monongahela River Basin. The
study is one of several performed for the Commission as part of this assignment and
provides data which will enable it to estimate costs of pollution abatement in the
Monongahela River Basin.
The report fulfills requirements for an effective, workable handbook on pol-
lution control costs and factors effecting these costs. The information in the report
is based on the latest technological developments and cost analyses of recent reclama-
tion projects.
Although the report was developed for the Monongahela River Basin study,
the cost estimates and supporting data should prove useful for all of Appalachia and
other areas with similar topography, mine drainage pollution problems and mining
history.
*Coal mine drainage abatement and treatment, *Refuse bank and mine fires,
*Mine subsidence control, *Abatement of pollution from sources other than coal
mining, surface mines, coal refuse banks, mine sealing, mine drainage treatment,
air pollution, solid waste, erosion and sedimentation control, abandoned automobiles
# Pollution control costs, *Monongahela River Basin (Pennsylvania,
West Virginia and Maryland)
19, Security Class.
(Report)
.'0, Secunty Ct .>,
21. No, of
vii,p«6
22. Price
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINQTON, O.C. 20240
Frank J. Doyle
Michael Baker, Jr. , Inc.
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