UNITED STATES
            WASHINGTON, D.C. 20460

This report is issued under Section 304(e)(2)(B) °f Public Law 92-500.
This Section provides:

         "The Administrator, after consultation with appro-
         priate Federal and State agencies and other inter-
         ested persons, shall issue to appropriate Federal
         agencies, the States, water pollution control agen-
         cies, and agencies designated under section 208 of
         this Act, within one year after the effective date of
         this subsection (and from time to time thereafter)
         information including ... (2) processes, procedures,
         and methods to control pollution resulting from —

         (B) mining activities, including runoff and siltation
         from new, currently operating, and abandoned sur-
         face and underground mines; ..."

This report, prepared under contract by the firm of Skelly and Loy,
Engineers-Consultants, Harrisburg, Pennsylvania, and Penn Environ-
mental Consultants, Inc.,  Pittsburgh,  Pennsylvania, for the Environ-
mental Protection Agency, provides general information on alternative
control measures.  It is intended to provide sufficient brief descriptive
information on such measures to guide the reader in the tentative
selection of alternative measures to be applied in specific cases.  The
details of application and methods of construction of each method must
be ascertained on a case-by-case basis by qualified professionals in
the mining and water pollution control fields.
                                  Rusjsell E. Train


October 1973
                       CONTROL POLLUTION FROM
                            MINING ACTIVITIES
                  U. S.  Environmental Protection Agency
                        Washington,  D. C.  20460
                 For sale by the Superintendent of Documents, U.S. Government Printing Office
                             Washington, D.C. 20402 - Price $3.40


         This report was prepared by Skelly and Loy, Engineers-
Consultants, Harrisburg, Pennsylvania, and Penn Environmental Con-
sultants, Inc.,  Pittsburgh, Pennsylvania (Contract No. 68-01-1830;
report submitted to the Office of Air and Water Programs, Water
Quality and  Non-Point Source Control Division).

         The Project Officer for EPA was Edgar A. Pash.  The
assistance and cooperation received from representatives of all Fed-
eral,  State,  and local agencies is gratefully acknowledged.


         This report provides information on processes,  procedures,
and methods to control pollution resulting from mining activities.  The
control methods included in this report are identified and described by
way of brief text,  generalized illustrations, and unit cost indications
where possible.  An extensive bibliography is appended with appro-
priate referencing in the description of each pollution  control method.

         This publication has been prepared to be a general overview of
available pollution control techniques.  Coverage of mining activities
for this purpose is not all-inclusive; activities not covered include
solution mining, milling operations, and coal washing operations.  It
does not provide the degree of detail that would be needed for this re-
port to be used alone as a pollution control or abatement  reference.
It is intended that this report will point the direction for further de-
tailed inquiry by State and local government agencies  and other parties
attempting to devise solutions to mining pollution situations.

         The described techniques should be considered as potential
alternatives for specific mining pollution problems.  The applicability
and effectiveness  of identified alternatives for  specific problems must
be determined on  an individual basis.  The applicability of any method
or combination of methods will depend upon many factors including
climatic, geologic,  engineering, economic, land use and aesthetic
considerations. The usual case will be that a combination of techni-
ques will be required to effect the  elimination or reduction of the dis-
charge of pollutants from  mining sources.

         The control measures described are conceivably applicable
to mining sources of pollutants regardless of whether those sources
are categorized as "point" or "non-point" sources. Point sources of
pollution are usually defined as those utilizing  any discernible,  con-
fined and discrete conveyance including any pipe,  ditch, channel, con-
duit, etc.  Non-point sources are defined, by inference,  as those dif-
fuse sources not confined  or conveyed in these ways, such as runoff
and seepage.  Abandoned, natural, and certain other sources not amen-

able to discharge regulation may be defined as non-point.  No distinc-
tion in applicability between point and non-point sources is made for
the control measures included in this report.

         The control measures and pertinent experience citations
selected for inclusion  result largely  from studies and pollution control
technology development that have occurred in association with coal
mining pollution problems in the eastern U.S. The regional emphasis
reflected herein is due to the greater availability and quantity of in-
formation from the East; and the short time available for preparation
of this report. Care should be taken in attempts to extend the results
of pollution control applications to regional situations that differ signif-
icantly from those described.

         Cost data are shown where appropriate to  indicate a broad
range of costs for individual control  measures. Any use of quoted
costs should be limited to gross estimation for planning purposes.


 I.   Introduction ,.	   1

 II.   Mining and Water Pollution	*«»...,..«.   4

III.   Mine Water Pollution Control	„	   8

IV,   The Manual - Water Pollution Control Methods  .	13

                       Surface Mining   	15

         1.0  Pollution Control Planning for Future Surface Mining  17

                 1.1   Method Discussion	19

         2.0  Controlled Mining Procedures	23

                 2.1   Method Discussion	25
                 2.2   Overburden Segregation	26
                 2.3   Mineral Barriers or Low Wall Barriers. . •  30
                 2.4   Longwall Strip Mining	33
                 2.5   Modified Block Cut or Pit Storage	35
                 2.6   Head-of-Hollow Fill	38
                 2.7   Bo>rCut Mining	42
                 2.8   Area Mining	46
                 2.9   Auger Mining  	49
                 2.10  Controlled Mineral Extraction	51

         3.0  Water Infiltration Control	53

                 3.1   Method Discussion	55
                 3.2   Reducing Surface Water Infiltration.  ....  57
                 3.3   Reducing Ground  or Mine Water
                       Influx	61
                 3.4   Water Diversion	63
                 3.5   Underdrains	67
                                - v -

4.0   Handling Pollution Forming Materials	    69

        4.1   Method Discussion	    71
        4.2   Use As Construction Material	    74
        4.3   Secondary Extraction	    77
        4.4   Relocation	    79
        4.5   Flooding	    82
        4.6   Underground Mine Backfilling	    84

5.0   Waste Water Control	    87

        5.1   Method Discussion	    89
        5.2   Reuse of Discharge	    90
        5.3   Evaporation  Ponds	    93
        5.4   Spray Irrigation	    96
        5.5   Subsurface Waste Injection	    98
        5.6   Regulated Discharge	   101
        5.7   Rerouting	   103
        5.8   Mineral Recovery	   105

6.0   Regrading	   107

        6.1   Method Discussion	   109
        6.2   Contour	   112
        6.3   Terrace	   114
        6.4   Swale	   116
        6.5   Area   	   120
        6.6   Open Pit	   122
        6.7   Hydraulic	   125
        6.8   Dredging	   127
        6.9   Auger	   129
        6.10  Highwall Reduction	   132
        6.11  Slope Reduction	   134
        6.12  Alkaline Regrading	   138
        6.13  Slurry Trenching	   140

7.0   Erosion Control	   143

        7.1   Method Discussion	   145

         7.2   Diversion	148
         7.3   Runoff Control	150
         7.4   Channel Protection	154
         7.5   Settling	156

 8.0  Revegetation	159

         8.1   Method Discussion	161
         8.2   Topsoil Replacement	  .  164
         8.3   Surface Preparation	166
         8.4   Soil Supplements	168
         8.5   Species Selection	172
         8.6   Planting Techniques	175
         8.7   Arid Areas	178
         8.8   Alpine Areas	182

               Underground Mining	183

 9.0  Controlled Mining Procedures   	185

         9.1   Method Discussion	187
         9.2   Preplanned Flooding	188
         9.3   Roof Fracture Control	192
         9.4   Controlled Mineral Extraction	195
         9.5   Controlled Atmosphere Mining	196
         9.6   Daylighting	198

10.0  Water Infiltration Control	201

        10.1   Method Discussion	203
        10.2   Increasing Surface Runoff	205
        10.3   Regrading Surface Mines	207
        10.4   Sealing Boreholes and Fracture
               Zones	2O9
        10.5   Interception of Aquifers	211

11.0  Waste Water Control	215

        11.1   Method Discussion	217
        11.2   Drainage Tunnels	218

12.0  Mine Sealing	221

        12.1   Method Discussion	223
        12.2   Double Bulkhead Seals	228
        12.3   Gunite Seals	231
        12.4   Single Bulkhead Seals	234
        12.5   Grout Curtains	238
        12.6   Clay Seals	  241
        12.7   Permeable Aggregate Seals	243
        12.8   Grout Bag Seals .	  246
        12.9   Regulated Flow  Seals	248
        12.10  Subsidence Sealing	250
        12.11  Dry Seals	251
        12.12  Roof Collapse	253
        12.13  Air Seals  	255
        12.14  Gel Material Seals	257
        12.15  Coal Mine Shaft Seals	258

               Treatment	261

13.0  Neutralization Processes	265

        13.1   Method Discussion	267

14.0  Neutralization With Limestone	271

        14.1   Method Discussion	273
        14.2   Treatment With Pulverized
               Limestone	276
        14.3   Treatment With Crushed Lime-
               stone Rock	284
                       - vm -

15.0  Neutralization With Lime	287

        15.1   Method Discussion	289
        15.2   Conventional Lime Neutralization
               Process	290
        15.3   High Density Sludge Process	296
        15.4   Combination Limestone - Lime
               Treatment Process	298
        15.5   Stream Neutralization	301

16.0  Sludge Disposal	303

        16.1   Method Discussion	305
        16.2   Large Settling Impoundments	306
        16.3   Air Drying	307
        16.4   Deep Mine Disposal	308
        16.5   Porous Drying Beds	309
        16.6   Vacuum Filtration	310
        16.7   Land Disposal   	311

17.0  Evaporation Processes   	313

        17.1   Method Discussion	315

18.0  Reverse Osmosis   	319

        18.1   Method Discussion	321
        18.2   Reverse Osmosis Process	323
        18.3   Neutrolosis Process	327

19.0  Electrodialysis	329

        19.1   Method Discussion	331

20.0  Ion Exchange Processes   	333

        20.1   Method Discussion	335
        20.2   Sul-Bisul Process	338
        20.3   Desal and Modified Desal Processes.  . .  341

               20.4  Two Resin System	345

       21.0   Freezing (Crystallization)	347

               21.1   Method Discussion	349

       22.0   Iron Oxidation   	351

               22.1   Method Discussion	353
               22.2  Aeration Methods	354
               22.3  Electrochemical Oxidation	357
               22.4  Ozone Oxidation	359

 V.  Glossary	361

VI.  Bibliography	367

                           I.  INTRODUCTION
         Mining of the various minerals which are natural resources
of the United States has been occurring in ever increasing magnitude
for the past 150 years.  This mining has resulted in significant water
quality deterioration within, and downstream from,  the mining regions.
Drainage from thousands of active and inactive mines has produced
chemical and physical pollution of both ground and surface waters .

         Lands adjacent to this water pollution have  been reduced in
economic value and potential use.  This water quality and land de-
gradation has severely restricted social-economic development of
many mining regions.

         Water pollution in drainage from mines occurs when dis-
solved, suspended,  or other solid mineral wastes and debris enter
receiving streams or encounter  fihe ground water system.  Mine
drainage includes water flowing from surface or underground mines
by gravity or by pumping,and runoff or seepage from mine lands or
mine wastes.  This pollution may be physical (sediments) or chem-
ical (acid,  etc.) and is frequently harmful to aquatic or other life.

         Water pollution from mining activities detrimentally affects
potential water uses in all forms:  municipal,  industrial, agricultural,
recreational,  navigational, private  development, and governmental.

         Mine drainage pollution is  similar to industrial waste pol-
lution, but is different in that mine  wastes,  or inactive mines that dis-
charge pollution,  are not the result of an industrial by-product.  Mine
drainage is  an indefinitely continuing, on-going source of pollution
that will continue  to pollute long after completion of mining,unless
control measures are effected.

         There are two primary types of pollution control—at-source
abatement (prevention of formation of the pollutants) and treatment of
the mine drainage.

         Pollution control technology applicable to mining activities
(including new, currently operating, and abandoned surface and under-
ground mines) has developed rapidly in recent years.  Much addition-
al research and demonstration should be pursued with respect to tech-
nology for mine drainage control.  However, many control methods
are presently available whose feasibility and practicability have been
subjected to varying degrees of demonstration and subsequent evalu-

         This report was produced to provide information that iden-
tifies and evaluates available technology for control of water pollution
from mining activities.  Information is provided herein on techniques
of at-source water pollution control applicable to the  mining industry,
whose practicability and feasibility have been demonstrated, or
strongly indicated, by the results of research.  Information is pro-
vided on chemical/physical mine water treatment methods, techniques
of water control or hydrologic  modification,  mine refuse disposal,
site  rehabilitation involving surface stabilization and  revegetation,
and measures that may inhibit or prevent the formation of pollutants
in mine water.

         Information is included on special problems  pertaining to
mine drainage pollution control.  The range of applicability of each
method is described and evaluated, with available (appropriate) cost
data provided wherever possible.

         The project encompassed pollution control methods for mining
in all the states. It included mining for organic materials (coal,
lignite, peat), gems (precious stones), heavy metals  and other metal-
lic minerals (gold, silver, lead, zinc, iron, copper,  and many others),
and earth minerals (talc, gypsum, limestone, dolomite, sandstone,
sand, nitrate, phosphate, and others). All mineable  materials are
referred to as "mineral" throughout this report.

         This manual is not intended for use as a comprehensive hand-
book on how to control pollution from mining activities.  Rather,  it is
intended to acquaint the reader with the many techniques now available
for use, and to guide him to the appropriate reference or references
for specific, detailed, comprehensive information on how to apply a
                                 — 2 —

particular technique.

         The manual is divided into three major components:  1) Sur-
face Mining; 2) Underground Mining; and 3) Treatment.  The sections
describing the various control methods are numbered sequentially
through each major component to facilitate use of the manual.

         Pollution control techniques are described, evaluated, limi-
tations and/or usefulness described, cost data for each technique de-
tailed, where appropriate or possible, and special problems defined.

         Previous demonstrations of techniques are explained in some
instances, and data relative to these demonstrations presented or
referenced.  Conditions and range  of applicability are defined where
possible (particular techniques that could be used for different sources
and types of mining than originally intended).

         Some pollution control problems  for which abatement tech-
niques have not yet been developed were uncovered by the study.  Addi-
tional  research has been recommended if appropriate, or suggestions
are made for using abatement techniques for other forms of pollution
control that may apply.

         The depth of the investigation was limited to an extensive
collection of data available  on the subject (published and unpublished),
interviews with experts on mining pollution control, and extrapolation
of experience  from as many agencies  as possible within the time and
resource framework available.
                                - 3 -

         The relationship between mining and water pollution is well-
known. Mining disturbs the earth and disequilibrates natural systems.
The resulting physical and chemical environmental changes often result
in water pollution. Most types of mining generate some form of water
pollution.  There are two major forms of water pollution — physical
and chemical.  Physical pollution is the increased erosion caused by
land disturbance,  resulting in increased sediment load.  Chemical
pollution is caused by exposing minerals to oxidation or leaching,  re-
sulting in undesirable concentrations of dissolved materials.

         Many miles of the  nation's waterways are degraded by mine
originated pollution.  The combined impact of physical and chemical
pollution from mining is large.  Ground water systems have also been
polluted by mining, but the  full impact is as yet unknown.  The magni-
tude of the problem is just recently being recognized by the general
public, as the present and future projected demand for clean water is
beginning to surpass the more readily available supplies.

         There are two general types of mining — surface and  under-
ground.  Surface mining is performed without going underground, or
more simply, to mine without having a roof of mineral.  There are
several forms of surface mining  — strip,  open pit, dredging and hy-
draulic.   Strip mining is accomplished when a large amount of over-
lying material is removed to expose an underlying deposit for extrac-
tion.  Open pit mining is quite similar to strip mining; the distinction
being that open pit has little overburden. Most of the material removed
during open pit mining is mineral, whereas most of the material re-
moved during strip mining is overburden or waste. The configuration
of each type of mine is also different.  Strip mining leaves an open
cut and large amounts of spoil; open pit mining results in a large open
hole with  only minimal spoil.

         Most strip mining  is performed to obtain coal, which is clas-
sified as a mineral in this report.  Open pit mining is performed for
various minerals, and many open pit mines are quarries where stone
                                - 4

for building products is mined.  Nearly all minerals have at one time
or another been removed by open pit methods, the most notable of
which are the huge open pit copper mines.

         Dredging recovers minerals from underwater.  Dredging is
confined to alluvial and sometimes colluvial deposits.  Gravel accounts
for the majority of dredging production.  Dredging has had widespread
use in the gold mining industry.  The mineral is either removed from
an existing body of water or stream, or an artificial impoundment is

         Hydraulic mining is performed by directing a jet of high
velocity water at an unconsolidated deposit.  It is used almost exclu-
sively for gold recovery.  The water-borne sediment is then passed
through a sluice box or other recovery mechanism.

         These forms of surface mining almost always result in silta-
tion, unless there is an impoundment to settle out the solids.  Any
disturbance of the land surface usually increases erodability of the
materials, and increased erosion occurs.  Chemical pollution occurs
where mining results in an increased rate of any pollution forming

         Surface mining is accounting for increased mineral produc-
tion each year.  This trend is expected to continue until near-surface
mineral reserves are depleted.  Building products were always re-
moved by surface mining methods.  Other minerals were more com-
monly mined by underground methods.  The advent of huge earth-
moving equipment, and increased costs of underground mining, have
caused the increased production by surface mining.

         Underground mines result in little surface disturbance   and
subsequently cause only minor physical pollution.  Surface rock dumps,
mine waste piles, and tailings  piles associated with underground  mines
do contribute significantly to siltation problems.  These piles are par-
ticularly vulnerable to erosion because of siting  (often in, or adjacent
to waterways), their common inability to support vegetation, and their
fine grained nature.  Though not completely documented, it is reason-
ably safe to say that underground mines are responsible for far more
                                - 5 -

chemical pollution than are surface mines.  Undermined areas may
eventually subside after mining has ceased  due to deterioration and
collapse of artificial or natural supports left in the mine workings.
Should subsidence occur  in developed areas, buildings, roads,  and
other man-made structures can be severely damaged.  Subsidence in
undeveloped areas can create fault-like scarps and sinkholes that can
result in diversion of natural surface drainages and  create hazardous
conditions for wildlife and livestock.

         The current status (active or abandoned) of a mine is impor-
tant in water pollution control.  The  vast majority of polluting mines
are abandoned.  Most water pollution problems come from these aban-
doned mines.  Active mines will not  be significant sources of pollution
after federal and state discharge requirements are fully implemented.

         Chemical pollution occurs when a water leachable mineral is
exposed  so that increased water leaching occurs,  or the mineral is
exposed  to increased oxidation, which in turn results in increased
leaching of pollutants.  The exposure of water leachable pollutants does
occur, but the majority of chemical pollution is generated via increased

         Several unusual forms of pollution occur that do not fit the
previous discussion.  Uranium mill tailings are radioactive, and are
washed or windblown into the water system where they continue to de-
cay, releasing radioactivity.  Chemical pollution can also result from
physical pollution.  This occurs where leachable materials are eroded
and dissolve after entering the water system or where erosion exposes
material to increased oxidation.

         Most chemical pollution results from oxidation of sulfide
minerals.  The  sulfides are relatively insoluble until oxidized.  Oxi-
dation results in acidity and the release of metals and sulfate to the
water system.   Acidity and metals are the primary pollutants that kill
aquatic biota. Acidities are detrimental because they cause  deteriora-
tion of water systems and water related facilities. Concentrations of
metals found in  mine drainage are often harmful or toxic to life.

         These sulfide minerals are  usually in a state of relatively

slow oxidation prior to mining. The oxygen access to these minerals
is very limited because of inundation by the water table or relatively
slow oxygen diffusion rates into the earth.  The sulfide minerals are
slowly oxidizing at their outcrop or through the small amount of oxygen
diffusing under ground.  The ground water  usually contains small con-
centrations (0 to 10 mg/l) of dissolved oxygen that allow a  very slow
oxidation of sulfides prior to mining.  Mining suddenly exposes large
quantities of sulfides to direct contact with oxygen and oxidation pro-
ceeds rapidly. Water pollution results.  Unfortunately, sulfides occur
with many of the minerals mined, and many of the metals are mined
as sulfides.

         Many mine slopes are unstable, causing failure (landslides),
and consequent deposition of sediments in valleys and stream channels,
erosion of newly exposed surfaces,  and damage to buildings and timber.
                                - 7 -

         Mine water pollution control is a relatively new field.
Mine water pollution abatement projects have been undertaken since the
turn of the century, but these early attempts were generally unsuccess-
ful.  A  concentrated research and  demonstration effort began in
earnest in the 1960's. Many new techniques were demonstrated with
varying degrees of success. The technology is still crude and largely
unavailable for large scope cleanup operations, particularly with  re-
spect to  deep mine discharges.  Many of the techniques in use today
are still somewhat theoretical.  Thorough documentation of their  ef-
fectiveness and applicability is not available.

         Mine water pollution control is generally achieved by chang-
ing the conditions responsible  for pollution production or by treating
the discharge. The following "Manual" portion of this report contains
descriptions,  evaluations, costs, and references for individual tech-
niques that can be used to control water pollution from mining.  Al-
though the techniques are listed  individually, very few are intended for
use as a complete abatement plan.  Combinations of several, techniques
are usually required to form a complete abatement plan.   For instance,
any type of regrading of a surface disturbance should be accompanied
by revegetation and possibly water diversion.

         Rarely is a single abatement technique a complete solution
for a mine drainage problem.  The  set of conditions occurring at  any
particular mine can be considered as being  unique to that specific
mine site.  Each technique used must be designed for each mine site,
considering the particular conditions of the  site.  A thorough physical
inventory and evaluation of each mine site should be undertaken before
an abatement plan  is formulated. The ultimate source and cause  of
the pollution should be known.  An abatement plan should be formulated
to specifically attack the cause of pollution for each mine site.  Formu-
lation of an abatement plan should only be done by individuals knowledge-
able in mine drainage control.  Many techniques  are available for use
in controlling pollution at many mines.  Different techniques will  have
different levels of effectiveness  and different costs.  Detailed engi-
                               -  8  -

neering is required for application of most of the techniques to a pai—
ticular mine site. Effectiveness of the technique will be dependent on
the manner In which the technique Is designed and constructed.

         Effective control techniques are not yet available for many
mine drainage problems.  Many of the deep mine discharges cannot be
controlled with available at-source  abatement techniques.  Drainage
treatment is then the only solution for many of these discharges.

         The Manual  is divided into three components:  1) Surface
Mining; 2) Underground Mining; and 3)  Treatment. The first two
major components deal with at-source techniques.  These are tech-
niques that can be utilized at the mine site. They generally Involve
a single capital expense and low or  zero operating and maintenance
costs. Some of the at-source techniques are exceptions, and require
continued maintenance and operation. The drainage treatment deals
with methods of treating discharge water to remove undesirable con-
stituents .

         Each technique Is evaluated to some degree.  Many of the eval-
uations are subjective and are based on the opinion of the report authors,
Evaluation of the effectiveness of a  technique is extremely difficult be-
cause of the  Interplay of numerous variables. Some techniques have
been field studied, but the published data is often insufficient for use
as a basis for a sound evaluation.  The reader will also have to make
his own evaluation of the probable effectiveness of any technique to be
used in a given situation.

         The techniques are grouped into broad method categories ac-
cording to general types of usage.  These categories tend to overlap
because the techniques do not all fit neatly into a category.  Effective
use of this manual requires that the reader be familiar with all of the
techniques.  This familiarity will allow the reader to evaluate all
available techniques applicable to a particular mine pollution problem.
More specific and detailed information can usually be obtained for each
technique from the listed references.

         After each technique is described and evaluated, the  refer-
ences that apply to that technique  are listed by arable numerals. The
                               — 9  —

specific references are then listed numerically and described in the
back of the manual. This was done to avoid the large amount of rep-
etition  that would  have been necessary to describe each reference
with each technique discussion.

         Cost data  is presented for the techniques when available.
These costs are intended to be used as an indication of possible price
ranges  and to give  the reader a rough idea of the  cost differential be-
tween techniques.  The costs of mine reclamation are extremely vari-
able and are entirely dependent on prevailing site conditions  and de-
gree of adaption of the technique to the site.  The project designer
will be  very  influential  in the project cost. Two designers can accom-
plish the same water pollution control goal for a particular situation
at widely varying costs. Strip mine regrading has  a relatively pre-
dictable cost, yet it can vary from $1,200 per hectare ($500 per acre)
for an area strip mine in nearly flat terrain to $12,300 per hectare
($5,000 per acre) in the Pennsylvania anthracite  coal region.  Simi-
lar and sometimes greater cost variations occur  with most of the
techniques discussed.  Reliable cost estimates can  only be made after
a detailed project evaluation.

         Special legal considerations pertaining to the techniques are
discussed in the technique or method sections.  There are general
legal considerations that apply to most of the techniques. The most
important question is the assignment or assumption of legal  liability
for polluting discharges. Responsibility for water pollution control
for active and future mines will be borne by the miner under new Federal-
State discharge requirements for the period of mine activity. However,
responsibility is unclear for presently active and future mines after
abandonment. Responsibility for currently abandoned mines will have
to be assigned or assumed by some party.  It would be  most difficult
to assign responsibility to present landowners because  of the high costs
of reclamation and small land improvement benefits. The original
mining  was done in a legal manner (at the time) and past operators
and owners would not be legally liable.   It is possible that the respon-
sibility for abandoned mine water pollution control would have to be
assumed  by the state or federal government.

         Acquisition of access rights must be obtained for construction
                               - 10 -

of abatement projects.  Access can be obtained by outright purchase,
gift, use of eminent domain, consent liens, lease, or simple access
agreements.  Mineral and water rights acquisition may also be re-
quired.  Some abatement techniques such as strip mine regrading and
underground mine flooding make future mineral extraction more diffi-
cult and sometimes unfeasible.  Mineral rights owners may have to be
compensated for their losses.   The mineral remaining in waste piles
may be considered as valuable property that may yield a profit in the
future. The question of ownership is difficult to establish between the
mine operator (or operators, as is often the case), the mineral rights
owner, and the surface owner.

         Multiple purpose abatement,  particularly with respect to sur-
face mine reclamation,can be an effective tool.  Benefits  other than
water pollution control can help offset construction costs  and increase
project justification. Surface mined lands can be returned to a useful
purpose for agriculture, silviculture, game food  areas, parks, golf
courses, airports, developments,  industrial sites, and scenic areas.
                               - 11 -


       - 13 -


   - 15 -


                  1 . 0
                 - 17 -


                      1.1  METHOD DISCUSSION
         Water pollution has been an integral part of most mining op-
erations in the past.  Most mine planners had designed their mining op-
erations with little or no regard for prevention of water pollution.  The
main planning element was always the economics of mineral recovery.
Quite often the cheapest means of mineral recovery resulted in the
largest water pollution problems.

         Recent water pollution laws have introduced a new economic
element - water pollution control costs - to be considered in mine plan-
ning.  Water pollution control costs can be extremely  high.  Foresighted
planning can minimize these costs and provide better water pollution

         Effective pollution control preplanning can eliminate pollution
from active mines  and minimize pollution that may occur after comple-
tion of mining.  Presently available technology can practically elimin-
ate water pollution by treatment of the mine water.  Use of water treat-
ment during mining has no effect on the levels of water pollution after
treatment ceases and the mine is abandoned.  Therefore, this section
of the report deals with preplanning  to reduce water pollution, both
present and future, by using at-source control techniques.

         Proper planning of mining and pollution control techniques
should follow the concept of a complete, comprehensive reclamation
plan.  This plan should have control  measures designed for all phases
of mining from initiation through completion.   Preplanning involves
acquiring complete information concerning the future mine site, defining
the reasons why mining could cause pollution from the site, and deter-
mination of available techniques to prevent or minimize formation or
transportation of pollutants.  Location of haulage and access roads and
other mine related facilities should be included in preplanning  .for
water pollution control.

         Mine site  planning is the primary step  in establishing any new
mining area and is the key to a successful, non-polluting  and  economical
                                - 19 -

mining operation.  Site characteristics should be carefully explored.
Site hydrology  is  important  because water is the major transport
mechanism.  If water influx to the mine area can be controlled, then
pollution can be controlled.  The future mine can be planned so that
water inflow (both surface and ground water) is minimized.  A surface
mine should be sited to prevent interception of runoff from adjacent
areas, either by avoidance of surface water flow channels or by con-
struction of diversion systems.

        Knowledge of availability and location of suitable material for
revegetation should be gathered.  The mining plan can be oriented to-
ward segregation and stockpiling of this material for later reclamation
efforts.  The location and extent of pollution-forming materials should
be known.  This permits  preparation of a mining plan that will handle
these materials in  a manner least conducive to formation of pollution.
The chemical and physical nature of the overburden should be carefully
explored so the various materials can be handled according to  their
pollution-forming potential.  There should be sufficient non-polluting
materials present to form the upper layer of the regraded surface upon
completion of mining. The amount of pollution-forming materials in the
overburden should  be small enough to permit effective burial during re-
clamation.  Mining in areas of toxic or pollution-forming overburden
should be limited to operations where demonstrated, effective, and
approved control measures will be implemented.   Samples of the over-
burden materials can be gathered by the use of core borings, test pits,
and soil sampling techniques.  These materials should be laboratory
tested to determine their revegetative and pollution-forming capacities
prior to mining.

        It is inevitable that some pollution-forming materials  will  be
exposed to possible leaching during most surface mining operations.
This exposure time can be minimized through the use of concurrent re-
clamation techniques.  Erosion of exposed material is a problem that
can be controlled by planning sediment ponds, diversionary measures,
compaction,  covering, or revegetation.

         Local geology and ground water flow patterns should be ana-
lyzed prior to mining.. Core borings,  exploratory pits, and topographic
mapping can reveal local geologic conditions that could increase water
                                - 20 -

pollution problems.  Mining in ground water discharge and recharge
areas should be avoided or special water handling measures included
in the mining plan.  Ground water can be intercepted by various tech-
niques to  reduce the amount of water reaching pollution^forming ma-
terials.  Knowledge of ground water levels can be useful in design of
open pit mines. Some  mines can be excavated below the water table
so they will partially flood upon completion of mining.  The open pit
can be designed to serve as a water collection and settling facility
during mining  and after completion of mining.

         Local soil and slope stability factors should be analyzed to
determine if special precautionary measures should be taken.  Some
soils are  highly erodible requiring rigorous erosion control measures.
Some geologic formations weather rapidly upon exposure to air and
water, become unstable, and are subject to sliding  and flowing.

         Physiographic considerations are also important. Special
mining techniques, such as modified block cut, parallel fill,  and slope
reduction,should be utilized in steep terrains to prevent massive land-
slides of spoil material.

        The methods to be used for overburden segregation and han-
dling should be developed prior to initiation of mining. Soil material,  pol-
lution-forming material and non-pollution-forming material should be
segregated during mining.  Planned removal  and replacement  of these
materials can eliminate costly excessive handling.  The  regrading  plan
should be integrated with the mining plan to reduce  costs and increase
effectiveness of the subsequent reclamation.

         Past mining and drilling history should be  investigated. Loca-
tions of underground mines and underground mine water pools should
be known.  Surface mine breakthrough into underground  mines can
cause the release of large quantities of impounded water, or provide
a means of entry for water and air to the underground mines.

         Local environmental conditions should be considered in surface
mine siting.  Some environments are extremely delicate and reclama-
tion techniques are not  very effective.  It  is difficult to revegetate sur-
face mined lands in arid, semiarid , alpine and tundra areas.  An  area
                               - 21 -

that is not revegetated after mining is subject to long term ravages of
wind and water erosion. Specialized mining techniques should be used
in areas of delicate environmental  balance.  Choice of plant species
for revegetation should carefully consider adaptability to local environ-
mental conditions.

         Types of information to be used in surface mine planning may

         1)  United States Geological Survey topographic maps.
         2)  Aerial and spectral imagery photographs and photo-
            grammetric mapping.
         3)  Soils maps.
         4)  Geologic, hydrologic,  and structure maps.
         5)  Mine maps for  adjacent underground mines.
         6)  Core borings with chemical and physical analyses.
         7)  Precipitation records.
         8)  Drainage areas tributary to a  mine site.
         9)  Analyses of surface and ground water flow.
        10)  Well (oil, gas,  water)  logs.

         Surface mine  preplanning  can greatly minimize the amount of
water pollution which will come from a mine.  However, in many cases
pollution will still result from exposure of pollutiorrforming materials
and inability of control mechanisms to completely prevent water from
entering a mine area.  Preplanning of collection and treatment systems
can result in effective pollution  control at  reduced costs.

         9,  10, 28, 42, 43, 49, 50, 61, 62,  69, 70, 72, 121, 128, 142,
 151,  153, 154, 177,  187
                                 - 22 -

      -23 -


                     2.1  METHOD DISCUSSION
         Certain mining procedures provide better control of water pol-
lution than other techniques.  This section of the report is devoted to
several of these techniques that are in use today.  These are not merely
regrading or reclamation techniques but are,in fact, mining techniques.
These mining techniques are not complete reclamation plans, but rather
methods of control that must be supplemented by additional techniques
in order to arrive at a complete  reclamation plan.

         The technique discussions that follow are intended to show
how each technique can be best utilized to accomplish an objective at
any mine site. All of the techniques will not apply to any one mine site.
The use of any technique will have to be adapted to the particular mine
                                - 25 -

                  2.2 OVERBURDEN SEGREGATION
         Overburden that must be removed to expose a mineral is sel-
dom homogeneous.  This overburden is usually a mixture of soil and
rock that has varying physical and chemical properties.  From a water
pollution standpoint there are three classes of overburden material:  1)
soil (material conducive to plant life); 2) clean fill; and 3) pollution-form-
ing material. The purpose of segregating overburden is  to keep these
three classes of material separated during mining so they can be effec-
tively utilized during later regrading.

         Spoil segregation was rarely practiced by miners in the past
because it was cheaper to pile all material together.  Reclamation of
these old abandoned mines is difficult, because good soil is lost and
pollution-forming materials occur throughout the spoil.

         Most of the water pollution from surface mines  (other than ero-
sion)  occurs as a direct result of exposing pollutiornforming materials
to oxidation.  These same materials are often covered by a ground water
table  and are isolated from free air oxygen prior to mining.  As such,
they do not have the opportunity to produce significant quantities of pol-
lution.  These materials are exposed during mining and  begin to oxidize,
forming water soluble salts.    These materials will continue to pro-
duce pollution as long as they are exposed near the surface of the  mine.
These pollution-forming materials can be returned  to conditions simi-
lar to pre-mining  by means of deep burial in the regraded material.
Burial helps to eliminate this free air contact and curtails oxidation.
Burial also improves the chances that the material will be inundated by
ground water, which will positively eliminate free air contact.

         One of the primary purposes of overburden segregation is to
stockpile  soil for later establishment of vegetation. Soil from all  sur-
face mine sites should be removed, stockpiled and  temporarily vege-
tated. This soil can then be spread over a mine surface on completion
                                -26 -

of grading.  An effective vegetative cover is often difficult to establish
in the absence of soil. Graded spoil material is often of coarse texture,
usually stony, and will not function to retain water at the surface, as re-
quired for a good vegetative cover.  Spoil is often a pollution-forming
material which can further inhibit vegetative growth.  Spoil material
can be dark colored and absorb sufficient solar energy to prevent vege-
tative establishment due  to high temperatures.  Most of these problems
can be eliminated by restoration of the original soil.
             Original  Ground  Surface
           Stockpiled  Spoil   Material

                    Topsoil   Stockpile,

Temporary  Vegetation
                    -Pit  Floor
         Although the illustration indicates downslope stockpiling of top-
soil and spoil, this practice is not really desirable. The stockpiled top-
soil can only remain buried for a limited time or it will lose its ability
to enhance vegetative growth.

         Segregation of pollution-forming materials prevents these ma-
terials from being  mixed throughout the regraded surface.  It also iso-
lates these materials for later burial during reclamation. A layer of
clean fill is first placed in a strip cut during regrading,  followed by
placement of pollution-forming material.  The remainder of the clean
fill is then compacted over the pollution-forming  material.  Stockpiled
soil is spread evenly over the entire surface and immediately planted
with seed to form a dense ground cover,  such as grasses and legumes.
                               - 27 -

         Overburden segregation has been successfully utilized many
times in the coal fields of eastern United States.

         Overburden segregation, when utilized with regrading and re-
vegetation, is believed to be one of the most successful methods of con-
trolling water pollution from surface mines.  This technique is appli-
cable only to active  mining operations where it is still possible to per-
form segregation.  It has only limited usefulness  in old abandoned sur-
face mines where the spoil material is a mixture  of various types of
overburden material.

         There are three basic limitations to this technique.  First,
there may not be sufficient material conducive to  growth to save.  Al-
ternate means of surface enhancement for vegetation should then be
considered.  The soil should be saved, even if there are only limited
amounts available.  Second, respreading topsoil may not be sufficient
for establishment of vegetation.  This is common in arid climates,
and additional measures will be required. The third limitation is cost.
Overburden segregation is an added mining expense. However, if ma-
terial handling is well planned, the additional expense can be minimized.
A miner operating in a competitive market may not have sufficient prof-
it  margins to allow for overburden segregation if other miners are not
using this technique. Therefore, overburden segregation may have to
be regulated by law  to prevent inequities in the mining industry.
         Costs of using this technique are borne by the mining industry
and passed along by increased price of the mineral mined. The
amount of increased mineral price is difficult to establish and will de-
pend upon how overburden is handled at each mine.  Good preplanning
to eliminate excessive materials handling can reduce this cost to a
minimal value.  Costs will also vary in accordance with the amount
                                - 28 -

of different overburden types present, terrain, geometry of the mine
site, mining  method, and equipment available.  The cost of using this
technique will have to be developed on an individual mine basis.

         Costs cannot be determined from past applications of this
technique because it is used in conjunction with other techniques.
Costs of this technique have never been isolated from costs of the en-
tire mining operation.
        33, 42, 43, 56, 61, 62, 69, 146, 151,  197,  198,  199

        Mineral barriers are portions of the mineral and/or overbur-
den that are left in place during mining.  These barriers are common
in the coal industry. Approximately a 9 meter (30 feet) width of coal
outcrop is left in place during contour strip mining.  The basic function
of this "low wall" barrier is to provide a natural seal along the outcrop.
This seal  helps retain surface and mine water within the mine during
the  mining operation. After mining the barrier helps to confine ground
water within regraded mine spoil.
•Original Ground Surface
                                                      Stockpi led
                                                      Spoil  Material
                             Temporary Vegetation
                                Low  Wall
                                Barrier x
   •Mineral Seam
                        Pit  Floor
                     CROSS   SECTION   OF
                    LOW    WALL   BARRIER
                            Figure  2.3-1
        Mineral barriers are also left between surface mines and ad-
jacent deep mines to prevent free passage of water between the mines.

        Mineral barriers appear applicable to the dredge mining in-
dustry.  A barrier could be left between the dredging operation and an
                              - 30 -

adjacent stream or body of water in order to contain large amounts of
sediment often generated from the mined area.

         Mineral barriers are probably useful in any surface mining
operation where there is a need to prevent the influx of water to a mine
or to contain water within a mine.
         Low wall barriers are applicable to most types of contour min-
ing.  However, they function best when mining has been performed to
the rise of a mineral seam.  Flow of ground water is toward the barrier
in this instance.

         Effectiveness of a barrier depends on integrity of the barrier
and relationship between the barrier and local hydrologic conditions.
For instance, barriers are not as effective on steeply inclined coal
seams as on flat lying coals.  A barrier often helps form a ground
water dam that will inundate a portion of a reclaimed surface mine.
The extent of flooding and water control can only be determined on an
individual application basis.  A degree of variability should be allowed
in the application of the  barriers.  A hydraulic evaluation should be made
at each mine to determine the type and extent of barrier to be utilized.

         Mineral barriers can be effective in flooding selected portions
of a mine site.  Pollutiornforming materials can be buried in these
flooded zones.

         Consideration should be given to preserving the integrity of a
barrier during and after mining.  One small breach in a low point of a
barrier can render an entire barrier ineffective.

         The barrier should be utilized in the context of a reclamation
plan that includes other  elements of control such as regrading, re-
vegetation,  and water diversion.
                               _ 31 _

        Cost of this technique is borne by the mining industry, miner-
al owner, and mineral consumer.  Unfortunately, a low wall barrier
utilized in contour coal mining contains the most easily extractable
mineral in the mine.  Leaving mineral in place costs the miner and
mineral rights owner profit that would have been gained from removal
of this mineral.   It increases  cost to the consumer because the miner-
al in the barrier would have been the cheapest to mine. The minerals
remaining in low wall barriers are not likely to be mined in the future
because of their geographic distribution over large areas.
        33, 61 , 126
                              - 32 -

                   2.4 LONGWALL STRIP MINING
         This concept is an adaptation of longwall underground mining.
It is being investigated for mining of seam-type mineral deposits such
as coal.  This method is being researched as an alternative to strip
mining.   Longwall mining removes coal without removing overburden.
A vertical trench is cut into a hill perpendicular to the coal outcrop,
then automatic mining equipment is  inserted in this trench and progress-
es through the coal seam in a direction parallel to the outcrop.  Coal
is cut by  machine and transported to the outcrop with a conveyor belt.
             -TOP OF SANDSTONE
             V  (EXPOSED) ' -
                      LONGWALL  STRIPPING SYSTEM
                             Figure  2.4-1
                                 - 33 -

The mine roof is held up by hydraulic jacks that progress forward with
the cutting equipment, allowing the roof to collapse behind the miner.
This type of mining does not leave void spaces as in an underground
mine.   It does not disturb the overlying material as in strip mining
and  could provide a high percentage of coal recovery.  Equipment is
controlled remotely keeping people out of the danger areas.
         There is little surface disturbance required for the use of this
technique, and most problems of strip mining are eliminated.  Com-
plete collapse of the mine roof after extraction may also eliminate
many water pollution problems associated with oxygen in underground

         Relatively flat, or very gently rolling, coal beds are required
for longwall strip mining.  It is likely that this type of mining will dis-
rupt local ground water conditions because of roof collapse.

         While this technique is discussed as being possible, feasibility
has not yet been established. The procedure is being evaluated eco-
nomically and environmentally by the  Environmental Protection Agency
with an actual demonstration project.   Longwall strip mining shows
promise of being a feasible mining method that will have a smaller
environmental  impact than other common mining  methods.

         In view of limited application to date, its use must be considered
         Costs are not yet available.
         61,  128,  137

                                 - 34 -

         This method was developed as an alternative to standard con-
tour strip mining methods to facilitate contour regrading, minimize
overburden handling, and contain spoil within the mined areas.  Con-
tour strip mining is usually accomplished by throwing  spoil off the
bench onto the area downslope from the mine.  This downslope material
is subject to landsliding and rapid erosion.  The downslope  material
must be brought back up to the mine site if contour regrading is required
upon cessation of mining.  Disturbed land area and the areas requiring
revegetation are much larger than the mined areas when the spoil is
cast downslope.

         In modified block cut mining only the material from the first
box cut is deposited in adjacent low areas, such as a saddle in the
ridge line, or at the head of a hollow.  Remaining spoil is then placed
in the mined portions of the bench.  Mining is accomplished in the
following manner.

         An initial cut is made from a crop line into the hillside to the
maximum highwall depth desired, and suitably cast in  a low area, or
placed in a suitable head of hollow fill area.  This cut  is usually three
times wider than each succeeding cut in order to  accommodate spoil
material from succeeding operations.  After removal of the mineral
vein from the open block, spoil material from the succeeding cut is
backfilled into the previous cut,  proceeding in one or both directions
from the initial cut.  This step simultaneously opens resource recovery
and provides the first step  in strip mine  reclamation.  After completion
of each cut, a void is left near the highwall where pollutant-forming ma-
terials encountered during  mining can be placed.   In this way, these ma-
terials can be directly buried  using acceptable coverings prior to final
regrading operations. When mining is completed, the entire mine is
regraded to resemble original contour with a minimum amount of earth
                                 - 35 -

         Cut I
     Highwall —••

Diagram  A
                                         Spoil  Bank
                                         Spoil  Backfill
                                         Outcrop Barrier
                                               Cut 2-V-

             Diagram  B
            Diagram  D
                                               Cut  3
Diagram   E
        Cut  5
             Diogram  F
                      MODIFIED   BLOCK   CUT
                             Figure  2.5-1
                                - 36 -
                          Adapted  from drawing
                          in  reference No. 69

         This technique appears to be a good technique to reduce en-
vironmental damage of contour surface mining in mountainous terrains.
Present experience with the method has been limited to terrain slopes
of less than 20° and  average highwall heights of 18 meters (60 feet).
It is expected this technique will prove feasible in even steeper terrain.

         There are definite advantages to a mineral industry in that
most of the overburden is handled only once, and grading and revegeta-
tion areas are reduced.  The technique is environmentally sound be-
cause of concurrent  reclamation,  the small disturbed area, use of con-
tour regrading,  and  confinement of most of the spoil to a mined area.

         The basic limitation of the technique is the problem of where
to place material from the first cut of overburden.  The amount of open
highwall needed for auger mining is limited, and could hinder auger
recovery of highwall reserves.
         It appears this mining method is no more expensive than any
other method where contour regrading is required, and could prove to
be less costly.

         The Mears Coal Company,  Pennsylvania has produced coal for
$7.30/tonne ($6.60/ton) delivered at the coal preparation plant, in an
area with a 20° slope.
        61, 69, 142
                               -37 -

                    2.6 HEAD-OF-HOLLOW FILL
         Head-of-holtow filling is often used with other methods of sui—
face mine restoration.  This is because this technique is essentially an
overburden storage method.  Basically, overburden material from ad-
jacent contour or mountaintop mines is placed in narrow, steep-sided
hollows.  The material should be properly placed in compacted layers
of 1.2 to 2.4 meters (4 to 8 feet) and graded so that surface drainage
is possible.  The natural ground should  always be cleared of woody
vegetation and drain (rock) should always be constructed where natural
drains exist or may have existed except in areas where inundation oc-
curred.  This permits ground water and natural percolation to exit fill
areas without saturating the fill.  This reduces potential landslide and
erosion problems.  Normally the face of the fill is terrace graded to
provide drainage to undisturbed lands.
         This technique of fill, or spoil material deposition,  should be
limited to relatively narrow, steep-sided ravines that can be adequately
filled and graded. Consideration must be given to the total number of
acres in the watershed above the proposed head-of-hollow fill as well
as the drainage, slope stability, and prospective land use. Revegetation
should proceed as soon as the various steps are completed (along with
the other erosion control techniques) to prevent erosion and siltation.
If all overburden from a surface mining operation is used or placed in
the fill, possible remaining exposure of the unreclaimed bench and
highwall could cause pollutional problems from sedimentation or chemi-
cal reaction.

         The technique can be utilized as a waste dump for overburden
                                - 38 -

          Strip  Mine Bench
                                       Ground  Surface


                                 Lateral Drain
                            Rock Filled
                            Natural  Drainway
                  CROSS   SECTION  OF
                         Figure  2.6-1
                           - 39 -
                                          Adapted from  drawing
                                          in reference No. 61

from terrace benches resulting from contour mining, or for removal of
entire  mountaintops (daylighting), where mineral recovery is partially
complete.  It may provide a means of cleaning up islands of land left
with no access, resulting from incomplete prior mining.   It can reduce
landslide potential and allow for full recovery of one or more mineral

         Effectiveness of the technique depends on good design and con-
struction of drainage facilities.  Special emphasis is required on water
management during fill and grading operations. If the installation is to
be permanent,  or is on a steep slope, fill benching techniques and per-
manent tile drains should be utilized to prevent slope failure.  These
practices will help fill stability and reduce associated pollutional prob-
lem.     Use of this method often results in creation of flat-lying land
in mountainous areas  that may help economic  development.

         A disadvantage of this method is that it leaves behind a large
amount of disturbed land.  Spoil is removed from a mined area and
thus increases the total  amount of disturbed area.  Some spoil or soil
should remain  on the mine site for subsequent revegetation.

         Undei—drainage containing high  concentrations of pollutants
sometimes results and may require treatment to meet pollution control
         Cost of head-of-hollow filling will depend on the method of min-
ing it supplements.  Such factors as haul distances, site preparation
and equipment used, must be taken into account at each proposed site.
Costs could be reduced in some applications where box cut or modified
block cut mining methods are used, due to a consequent reduction in
material to be discarded outside the mine bench.  No specific costs are
given since this technique is part of a mining procedure.
                                - 40

                                 41 -

                       2.7  BOX-CUT MINING
         The box-cut method utilizing only one cut is essentially a nor-
mal form of contour strip mining which leaves an undisturbed bench
over a low wall.  Overburden is discarded downslope, using an accept-
able slope control technique and eventually regraded, usually to a re-
verse terrace plan.

         The box-cut using two (2) cuts is a refinement of the contour
mining procedure.  Initially, vegetation is removed and suitable top-
soil overburden material stockpiled.  Remaining overburden is removed
to a pre-determined elevation and cast downslope.  The box-cut opera-
tion then begins nearest the exposed highwall with this overburden cast
on the bench  over the low wall  barrier.  The mineral is extracted from
the first cut opening.  A second cut is then made toward the low wall
barrier with  the spoil material cast into the first cut trench.  After
completion of mining the remaining second cut overburden is regraded.
         Use of this technique as a water pollution control procedure is
questionable.   Unless some very careful planning is done and operations
carefully controlled, further problems may develop.  The method is
generally applicable to surface mining on rolling to moderately steep
terrain,  and may be applied to multiple-seam vein resource recovery.
However, steep slope conditions could severely limit the application,
especially when the spoil angla of repose is closely aligned with natural
ground slope.  If suitable head-of-hollow disposal were possible,  indis-
crtminant downslope casting of overburden or spoil could be partially
or completely eliminated.
                               -42  -

  Diversion  Ditch


     Solid  Bench-^
Fill  _
Bench  \
Mineral  Seam
               Original  Ground  Surface-

                         IST  STEP
                                 Toe of
 •Diversion Ditch
                      X"'.-«'A_Spoil from

                      ;.->;:-i/:^ lit  Pit
                 Original Ground  Surface

                         2ND  STEP
             BOX-CUT  MINING  (2  CUTS)

                         Figure  2.7-1
                            - 43 -
                                              Reference  No.  61

•Diversion  Ditch

                                  Excess  Spoil  from
                                   st  a 2nd  Pits
Spoil from
       Mineral  Seam
                  Original  Ground Surface
                                                Toe  of
-Diversion  Ditch
                 Original Ground Surface

                         4TH   STEP
                                    Reverse Terrace  Slope

                                           \.   Toe of
             BOX-CUT  MINING   (2  CUTS)
                         Figure  2.7-2
                                       Reference  No. 61

         The problem of preventing slide conditions, spoil erosion,and
resultant stream sedimentation,is present in any downslope spoil dis-
posal technique.  The higher and often better grade portion of the spoil
is cast downslope,  leaving the materials with higher pollution potential
on the bench.  Reverse terrace grading  induces infiltration to these
toxic materials,  causing a pollution problem.  Because of this, the
technique may have little use as a water pollutant abatement technique.
However, the technique is conducive to  auxiliary mining methods such
as auger or longwall  procedures.

         Regrading is an essential part  of reclamation.  In this tech-
nique, backfilling, which often results in a reverse terrace, is done with
poorer material.  This limitation could  be overcome somewhat, if soil
segregation is practiced, topsoil put back as a  final cover, and properly
vegetated.  Spoil segregation may be rather difficult to accomplish us-
ing this mining method.  Other reclamation  procedures will also be  re-
quired, such as water and erosion control.  Reverse terrace regrading
is often used to  reclaim box-cut mining, and is usually a poor abatement
         This is a relatively inexpensive mining technique.  Costs are
not given for mining techniques.  Costs will vary according to the min-
ing plan and local factors at each mine site.
                               -45 -

                        2.8  AREA MINING
        Area mining is generally used in relatively flat terrain where
mineral seams are roughly parallel to land surface.  As its name im-
plies, area mining involves removal of large blocks of minerals (where-
as contour mining removes narrow bands of mineral). Area mining has
been used almost exclusively for coal, but could be utilized for any min-
eral in seams whose geometry is similar to coal.
                         AREA    MINING
                           Figure 2.8-1
                                                   Reference No. 166
                              -46 -

        An area mine is usually started with a box-cut, or trench, ex-
tending to the limits of the property or vein deposit, with a concomitant
parallel spoil bank.  Spoil material from each successive parallel cut
or trench is placed in the preceding trench. The last cut or trench is
bounded by overburden material on one side and an undisturbed highwall
on the other.
         Area mining is presented as a water pollution control tech-
nique because it has fewer associated problems than contour mining.
Area mining is generally performed in gently rolling or flat-lying ter-
rain.  Surface water velocities are low around the mine because of
gentle slopes.  Many area mines, especially where there is no outcrop,
have little or no surface water discharge.  Erosion may be heavy on the
mine site, but a large portion of the sedimentation occurs within the
mine,  and never reaches external surface flow channels.  Spoil land-
slides are rare in area mining, because the spoil is usually contained
within a relatively flat-lying  mined area.   Regrading area-mined lands
is usually less expensive than regrading contour-mined lands.

         Area mining has a greater potential for ground water pollution
than does contour mining.

         Overburden segregation, water diversion,  regrading and re-
vegetation are necessary in conjunction with area mining to eliminate
water pollution, improve aesthetics,  and return  land to useful func-
tions.  Generally, regraded  area-mined lands could be used for agri-
culture, silviculture, recreation and development purposes.  If water
quality is acceptable from an active area mine, the pond that may be
allowed to form in the final cut could  remain and possibly be used for
recreational or other purposes.

         Area mining will likely be used extensively in development of
western coal fields.  Revegetation has been extremely difficult to se-
cure in these arid and serniarid regions, and this problem should be
solved before large scale area mining is conducted in the west.
                               -47  -

         This is a mining technique and not a reclamation technique.
Costs of reclamation are an integral portion of the total mining opera-
                                -48 -

                         2.9 AUGER MINING
         This mining method is used to recover coal behind a highwall
of a surface mine.  Large augers are driven horizontally about 60
meters (200 feet) into a coal seam.  Coal is recovered in a manner
similar to wood chips from a drill bit.  Successive parallel holes are
driven into the coal seam until the operation becomes unfeasible.  The
strip  mine is then backfilled over the auger hole openings.  Recovery
is often less than 40%.
         Auger mining is usually used to extract additional coal from a
completed surface mine. Use of auger mining must be carefully con-
trolled to prevent penetration into adjacent deep  mines.  Special com-
paction procedures should be employed when backfilling auger holes.
Augering creates, in effect,  many small deep mines.  If the auger
operation is carried out in acid producing seams of coal (where the
seam rises from the outcrop) with a resulting acid water discharge,
problems of adequate sealing will occur.

         If auger mining is performed properly and extreme care exer-
cised during and after augering,  pollution can be minimized.  Compacted
and revegetated fill over the  auger holes may help prevent influx of
free air  oxygen to the holes.   Lack of free air oxygen will then prevent
formation of pollutants after  oxygen present in the holes has been con-
sumed.  Barometric fluctuations may still cause entry of free air
oxygen to covered,  deep auger holes, and proper design of auger plugs
is necessary.
                               - 49 -

        This is a mining technique and not a reclamation technique.
Therefore, costs are not presented.
        61, 135
                               - 50 -

         This procedure is based on the fact that pollution-forming ma-
terials are not evenly distributed throughout a mineral seam.  This
phenomenon is particularly evident with coal. Of the many coal seams
occurring in a given area, only a few are usually pollution forming.
Lateral  variabilities  also occur in particular coal  seams.  A specific
coal seam may be acid in one area and alkaline in adjacent areas.

         Water quality and core boring sampling in polluted watersheds
often indicates that pollution is not evenly distributed, but is concen-
trated in localized areas.  A small portion of a watershed is generally
responsible for a majority of the pollution.

         This technique requires use of extensive water quality sam-
pling to determine "hot" areas of the mineral seams.  Location and
mapping of areas or mineral seams with high pollution potential can  be
a valuable control tool.  Stringent water pollution control measures  can
be utilized in  areas of known high pollution potential.

         Controlled mineral extraction is sometimes used for total min-
eral extraction,  or "daylighting" an area by mining all salable minerals
during one massive mining and reclamation operation.
         Much future mine water pollution can be controlled or reduced
by not mining or by strictly regulating mining in known high pollution
potential areas.  It may be possible to avoid mining minerals where high
pollution potential exists.  Conversely, there may be reserves of mine-
able minerals in low  pollution potential areas where mining could be
                                - 51 -

         The first step toward utilization of this procedure is establish-
ment of a water quality sampling program. This is followed by data
analysis leading to identification and mapping of high pollution potential
areas.  These maps should not consider aerial extent alone, and should
include data on a particular mineral seam. These maps could be devel-
oped for each individual mineral seam.
        This is a regulatory technique.  Consequently, costs are not
        148, 198, 199, 200, 207, 208
                                - 52

       3 . 0
    -53 -


                     3.1  METHOD DISCUSSION
         Most of the water pollution stemming from surface mine wastes
is caused by surface water erosion and pollutant leaching due to water
infiltration.  Virtually all surface mine wastes consist of loose materials
which are extremely permeable and easily eroded.  Generally, erosion
is easier to control than infiltration.  A comprehensive discussion of
erosion control is included in the Erosion Control section of this manual.

         Unlike erosion, the source of infiltration is not always readily
defined, and control is usually  more complex.   Infiltration  can result
from natural subsurface water  movements, waters escaping from adja-
cent underground mines, or downward percolation of surface waters and
direct rainfall.

         Control of surface infiltration involves either isolation of waste
material from the water supply or decreasing surface permeability.
Methods of disposing of mine wastes are discussed in the "Handling Pol-
lution-Forming Materials" section of this manual.  Generally, it is not
feasible to remove the large amounts of waste material generated by
mining operations.  Also, the waste material may be needed as back-
fill material for regrading.  Under these conditions, if infiltrating water
is causing formation of pollutants, abatement will require on-site control
of infiltration.

         Controlling water infiltration from rainfall and subsurface
sources can be accomplished by placing impervious barriers on or
around the waste material, establishing a vegetative cover, or construct-
ing underdrains.  Impervious barriers, constructed of clay, concrete,
asphalt, latex, plastic, or formed by special processes such as carbon-
ate bonding,  can prevent water from reaching the waste material.

         A dense vegetative cover may in some  instances decrease in-
filtration.  However, the reverse is more  often the case.  Vegetation
tends to reduce the velocity of water, thereby inducing infiltration.  A
vegetative cover will build up a soil profile, which tends to increase the
surface retention of water.  This water is  available for evaporation and

can result in a net decrease in the amount of water entering underlying
materials.  Vegetation also utilizes large quantities of water in its life
processes (again decreasing the amount of water that will reach the under-
lying material).  The net effect of vegetation is probably an increase in
infiltration, and is therefore not discussed in this section.  Vegetation,
however, is one of the most effective water pollution control techniques
(for reasons other than reducing infiltration).  Methods and techniques
for establishing a vegetative cover are included in the "Establishing a
Vegetative Cover" section of the manual.

         When infiltration is caused by interception of surface flow, it
will usually be beneficial to divert the flow.  One  or more of the tech-
niques discussed in the Erosion Control section of this manual  may be
employed for this purpose.

         Underdrains are often used to control water infiltration after
it has entered the waste material.  By offering a quick escape route,
contact time between water and any pollution-forming material  contained
in the waste is reduced.  Also, water flow paths through pollution-form-
ing materials are shortened.  The possibility of a fluctuating water
table is eliminated.  Underdrain discharges should be monitored to
determine any pollutant pickup that may occur.

         A number of techniques are described in the following section
which can be used to control water infiltration in different situations.
In some cases, the use of any infiltration control may prove to be in-
effective or too costly.  In these situations it  may be more viable to use
one or more of the techniques discussed in the Mine Waste Water Con-
trol section of the manual.

         Devices installed to control water infiltration may require long
term  maintenance.   This especially applies to diversion and drains.
                                - 56 -

        This technique involves reducing surface permeability of pol-
lution-forming materials.  This can be achieved by placement of imper-
vious materials such as concrete, soil cement, asphalt,  rubber, plastic,
latex and clay.  This effect can also be achieved by surface compaction
and by chemical surface treatment (such as carbonate bonding).

        Concrete and asphalt are applied in a layer on the pollution-
forming material to form a water tight seal.  The remaining  materials
may be left exposed, or may be covered with soil, depending upon the
material and future land  use.
         Original  Ground Surface

                        Backfilled Grade  Surface
                                  •Clean Spoil ft  Topsoil
                                          Clean  Spoil
      TO  BURIED
       Figure  3.2-1
                              -57 -

         Compaction of the existing surface materials will decrease in-
filtration to some degree.  Degree of success will depend on the physical
nature of the material and equipment utilized for compaction.

         Latex soil sealant is applied as a dry compound at a predeter-
mined depth in existing surface material.  The latex compound reacts
with infiltrating ground water to form a thin, impermeable film, or
layer, at a desired depth.

         Carbonate bonding is a physio-chemical application to an exist-
ing surface which produces a cement-like product.  The procedure in-
volves roto-tilling lime hydrate and water into the material, followed
by installation of plastic perforated pipes.  The pipes distribute pure
carbon dioxide gas through the lime hydrate-waste material mixture,
converting the lime hydrate into a hard carbonate material which acts
as a surface sealant.
         Asphalt and concrete are excellent sealants, but are expensive.
The only presently economically feasible way to use these sealants is
in multipurpose  reclamation such as constructing parking lots, build-
ings,  airport runways and roads over pollution-forming materials.  They
are too expensive for use as a. single purpose water pollution control
method. Use of pollution-forming materials in highway road base con-
struction to eliminate surface water infiltration is a technique being re-

         Use of rubber and plastic as  coverings has been accomplished
experimentally.  They are extremely  prone to damage when exposed,
and do not appear feasible without an extensive maintenance program.
Attempts have been made to  cover them with soil, but the equipment used
to place the soil usually damages the covering.  A soil cover on these
materials is not very stable  and tends to erode and slide.  The soil cov-
erings would also vegetate, which could result in root damage to the seals.

         Compaction is one of the cheapest techniques, but unfortunately
                                -58 -

most mine wastes cannot be compacted sufficiently (without use of other
techniques) to significantly control water pollution.

         Carbonate bonding is essentially in the experimental stages.
However, it shows promise of being a viable sealing technique.  Further
experimentation in practical situations should be performed before ex-
tensive use of the technique.

         Use of latex as a soil sealant proved ineffective in a demonstra-
tion project in Clearfield County, Pennsylvania.

         Clay appears to be the best practical sealant material.  It is  one
of the least expensive and yet most maintenance free.  Clay is compacted
over the pollution-forming material, and should be covered with soil to
prevent desiccation, failure, and subsequent erosion.  Feasibility of clay
as a sealer usually depends on local availability of clay.

         Pollution-forming materials should be graded into the smallest
 practical area prior to sealing.

         All of these sealants are subject to failure, either chemical
 or physical, and will require some maintenance.
         Costs for this technique can vary widely due to the nature of
 the sealant materials.  Individual costs are dependent on such
 factors as volume of material required, thickness and area of appli-
 cation, labor, material and equipment costs.  Clay may cost $2.30 to
 $7.80 per cubic meter ($1 .75 to  $6.OO per cubic yard) including instal-
 lation. Concrete costs $39 or more per cubic meter ($30 per cubic
 yard), and 5 to 7.5 centimeter thick (2" to 3") gunite applications  cost
 from $19 to $22 per square meter ($1  .75 to $2.00 per square foot).
 Asphalt Installation may range in cost from $2.40 to $6.00 per square
 meter ($2.00 to $5.00  per square yard).   Carbonate bonding costs
                                - 59 -

range from $0.95 to $3.00 per square meter ($0.80 to $2.50 per
square yard) depending on the desired application method.   Latex,
rubber and plastics are still largely experimental and, as such, have
no definite established unit costs.(They are,  however, rather expensive
and are suitable for only small areas.  For reference and estimating,
a cost for rubber ranges from $5.40 to $10.75 per square meter
($0.50 to $1 .00 per square foot) installed,  and plastic may be about
one-third  the cost of rubber, depending on  the selected thickness.
         13, 19, 22, 44, 97, 111 , 168
                              -60 -

         Pollution caused by passage of ground or mine water through
pollution-forming materials can be eliminated or reduced by imperme-
able barriers.  Materials such as clay, concrete, or concrete block
walls are placed between the water source and the pollution-forming

         An impermeable liner can be placed against the highwall of a
surface mine to prevent the influx of ground water.  This application is
seldom used except where there are auger holes that require sealing,
or the surface mine has broken into an underground mine working.
Underground mine openings encountered during stripping  are often
sealed with clay or concrete block walls.
                      -Original Ground Surface
                                    Backfilled Ground Surface
                                      Impermeable Material
                      CROSS SECTION OF A CLAY LINER
                               Figure  3.3-1
                                - 61 -

         Use of impermeable barriers to stop flow of ground water has
not had sufficient usage or documentation to judge its effectiveness.
Theoretically it should be effective,  but its use would be limited to spec-
ific problem areas because of cost.

         Clay liners placed against the highwalls of strip mines appear
to be effective in controlling pollution from auger holes.  They also hold
promise for sealing underground mines under low water pressure con-
ditions .
         Because of the high variability of technique application,  only
unit prices are shown.  Clay ranges from $2.30 to $7.80 per cubic
meter ($1.75 to $6.00 per cubic yard) including installation and depend-
ing on source and haul distance.  Concrete,  in place,  costs approxi-
mately $39 per cubic  meter ($30 per cubic yard) depending on area
labor and materials cost.

         Site preparation will involve additional costs, depending on
present site conditions.
         44,  47, 70, 111, 135
                                - 62 -

                      3.4  WATER DIVERSION
         Water diversion involves collection of water before it enters
the mine area, and then conveying it around a mine site.  This proce-
dure decreases erosion,  reduces pollution and reduces water treatment
costs by reducing the volume of water that needs to be treated.

         Ditches, flumes, pipes, trench drains and dikes are all com-
monly used for water diversion.  Ditches are usually excavated upslope
of the surface mine to collect and convey the water.  Flumes and pipes
are used to carry water down steep  slopes or across regraded areas.
Riprap and dumped rock are sometimes used to reduce water velocity
in the conveyance system.

         Water diversion can also occur within a surface mine.  Drain-
ways at the bottom of a highwall are helpful,in many cases, to convey
entering ground water from the mine prior to its contact with pollution-
forming materials.

         Ground waters can be diverted by pumping water from the flow
path area prior to entrance to the mine.  In some instances, it may be
cheaper to drill holes  and pump ground water away than to treat the
water after it passes through a mine.

         Surface water diversion could be applied to many large valley
fill bony piles in  the east and tailings piles in the west.  Many of these
waste piles were built across valleys (natural watercourses) causing
streams to pass through the pollution—forming materials.  This water
can be diverted around or conveyed  through the waste material.
                                - 63 -

                               Compacted Fill To Prevent
                               Ponding At Toe
0 r i g in a I.. Qr.o.u n.dl Surf acis
                        *-C Diversion
                   CROSS   SECTION  OF
                                          Top Of Spoil

 Toe Of
              Terrace —v Slope      ..^issSSS^^
                     CROSS  SECTION OF
                         Figure 3.4-1      Adapted from National
                                         Coal Board,Great Britian
                           - 64 -

     -Diversion  Ditch
                               Spoil  Bank

                                         Outlet -fei-^-^-J
                                             Pipe  or  other
                                             Drainage Structure
BaqkfiUed_ Bench V_ In)et ^G-^_^^==
^^y^^^- Original Ground  Surface ^ ^^
                                                        Riprap   Ditch
                       WATER  DIVERSION
                            Figure 3.4-2
                               - 65 -
Adapted  from drawing
in reference No.  166

         Surface water diversion is an effective technique for reducing
water pollution.  It can be applied to almost any surface mine or mine
waste pile.

         A water diversion system should be properly designed to ac-
commodate expected volumes and water velocities.  If the capacity of
a ditch is exceeded,water can erode the sides and render the ditch use-
less for  any amount of rainfall.

         In many instances, diversion can be accomplished at a lesser
cost than would be required to treat an equal volume of  water.
         Costs of various items to effectively handle water are outlined
in Erosion Control,  Diversion, Section 7.2.
         34,  56,  115, 166
                               _ 66 _

                         3.5  UNDERDRAINS
         Underdrains of rock or perforated pipe can be placed below pol-
lution^forming materials to quickly discharge infiltrating water.  These
devices shorten the flow path and  residence time of water in the waste
materials.  Underdrains are designed to provide zones of high perme-
ability to collect and transport water from the bottom of the piles.  A
common method of construction is to use trenches filled with rock.

         Underdrains should prove effective for use with bony storage
areas and large tailings accumulations.  They are best suited for in-
stallation prior to creation of the  pile.  They can also be installed in
existing  piles, although the cost is higher.
         These drains have been tried on western tailings piles, but
their effectiveness has not been documented.  They are recommended
for use with the head-of-hollow mining technique. The concept is theo-
retically sound and will probably be demonstrated in the near future.

         There are certain limitations to use of underdrains. They
should not be used where inundation has occurred, because they will
drain the pile and cause an adverse effect.  They should only be used
in piles where the water table is fluctuating, and flow is in direct re-
sponse to rainfall. Care must be taken during design to preclude the
possibility of fines clogging the completed underdrain installation.

         Underdrains could be considered for use any time a new pile
is to be created.  All springs and seep areas that will  be covered with
pollution-forming materials should have this water conveyed  from the
                                - 67 -

area.  The flow from underdrains should be monitored for quality deter-
minations because such flows are generally of poorer quality than re-
ceiving waters.
        Costs are extremely variable and should be developed for the
particular usage.  The price range for these drains should be approxi-
mately $5.00 to  $33.00 per lineal meter ($1.50 to $10.00 per lineal
foot) depending on the type and size used.
                                - 68 -

     4 . 0
    - 69 -


                       4.1  METHOD DISCUSSION
         The pollution-forming materials discussed here are particular
wastes generated by mining operations and discarded on the land sur-
face. These materials are exposed to oxidation, weathering, erosion
and leaching. They are typically "sluggers", meaning they discharge
large quantities of pollution for short durations during and after rain-
fall, unless there is continuous leaching by intercepted surface flow.

         There are many techniques  available to control pollution from
these materials. Four of these techniques are discussed in this section
but many of the  other surface mining control techniques can also be uti-
lized in conjunction with these four.   Water infiltration control tech-
niques are generally applicable. Special revegetationtechniques should
be employed (such as spreading soil) because these materials are often
toxic to plant life.  Certain ore milling processes introduce highly un-
desirable substances into the waste.   Covering with soil and vegetation
is one of the best techniques for controlling water pollution from mine
wastes.  This method is discussed in the revegetation section of this

         Most of the reclamation of pollution-forming materials to date
has been either  removal for burial or regrading, revegetation and
water diversion in-situ.  These have met with varying degrees of suc-
cess .  Effectiveness  is difficult to document because  of the highly var-
iable nature of the discharge.  Extensive before and after water samp-
ling would have  to be performed at several reclamation sites to docu-
ment effectiveness.

         Attempts at revegetating uranium tailings in the Utah-Colorado
area have been  successful to varying degrees. Uranium piles have to
be stabilized to prevent erosion from carrying radioactive material to
nearby streams.  Uranium piles are often in arid to  semiarid  regions
and require irrigation for vegetative growth. Irrigation of uranium piles,
however, may cause leaching of radium into the regional water system.
Riprap is used to stabilize one uranium pile in an area where rainfall is
low and  vegetation has not been established.
                                - 71 -

         Many techniques have been attempted with coal waste piles in
eastern coal fields.  Water diversion, removal  for burial,  regrading,
covering with soil and impermeable materials,  and direct planting after
roto-tilling limestone  into the surface,have all been successfully demon-
strated .

         Waste slimes of the southern phosphate industry are a parti-
cular problem, because they cannot be dewatered economically. The
volume of waste slime is  often larger than the size of open  pit mines,
requiring use of holding ponds for disposal of the excess.  The slime
is incompetent and will not support weight.  It is also toxic and will not
support vegetation.  Attempts have been made to utilize the slime for
irrigation or for derivation of secondary products.  These attempts
have not been successful as yet.  The only technique reported to show
any promise is to  mix the slime with sand overburden genereited during
mining.  This reportedly increases competency of the slime to a point
where it will support development.

         These mine wastes create serious water pollution problems
throughout the country.  These wastes are reported to be the source of
more water pollution than mines in western United States.  The tailings
are indiscriminately scattered about the land  surface and often occur in
low points where they intercept surface drainage.

         There is  an urgent need for demonstration of some of the tech-
niques in this  report and  development of new techniques for control of
water pollution from abandoned mine wastes.

         There are special legal problems associated with  mine wastes.
Most of the wastes contain residues of the mineral mined,  and small
amounts of other valuable minerals.  These wastes may become valuable
when technology and mineral markets advance to where  secondary re-
covery is feasible.  As such,  many of these piles have a certain, diffi-
cult-to-define value and may be treated as personal property.  Owner-
ship of the wastes is sometimes  in question.  The material was origi-
nally deposited as a discard,  and ownership  may or may not  pass from
the miner to the surface owner.  This has not been established legally,
and the miner may have a legitimate claim to ownership .  Many mine
                               - 72

waste piles were developed over long periods of time with contrioutions
from different miners. This, of course, further confuses the owner-
ship question.  Ownership should be established or other legal provi-
sions made before removal of a waste pile.

        Waste piles should be examined for mineral content prior to
implementation of water pollution control procedures.  There may be
sufficient recoverable mineral present to significantly offset the cost
of control measures .  Secondary recovery could turn a water pollution
problem into an economic benefit.
                               -73 -

        This is a multiple purpose technique that eliminates a water
pollution problem and results in a building product.  Control of water
pollution is extremely costly and can often be offset if waste material
can be utilized as a salable product.

        One promising technique is utilization of mine wastes for road-
bed subgrades.  Should this prove  feasible, a large amount of existing
mine wastes can  probably be utilized in highway construction in the
mining areas.
                         Paved  Roadway
To Level Above
Surface Water Or-
Flood Of Record,
                         _Rock Embankment
                          Graded Material
                            Figure  4.2-1
                              -74 -

         Experiments have shown that copper mill tailings are useful
in making brick.

         The Appalachian Regional Commission is presently funding
research within the Monongahela River Basin that may develop uses
for coal  mine wastes .
         Use of mine wastes In construction materials is in the theo-
retical/experimental stage.  Several uses may be developed In the near
future. Research and demonstration is definitely required.  Physical/
chemical properties of various mine wastes will have to be explored to
determine further uses.

         Use of mine waste as fill in the center of a road base should
hydraulically isolate  pollution forming  materials.  A paved highway
surface will prevent infiltration of water from above, and rock under-
dralns will keep a ground water level from rising Into the waste.
Physical properties of the mine wastes comprise a  basic limitation.
Wastes may require blending or mixing with other materials. Legal
problems concerning  ownership and acquisition of mine waste will
have to be solved.

        This technique has good potential to help solve the nation's
mine waste problem.  Possibilities  of utilizing government subsidies
to encourage private sector development to produce construction ma-
terials from mine waste piles should be explored.
         Costs incurred by such variable factors as accessibility, haul
distance, type of material, and local labor and equipment rates have to
                                - 75 -

be considered to develop a representative cost for this technique.

         For estimating purposes, a rate of $1.10 to $2.20 per tonne
($1.00 to $2.00 per ton) would be reasonable since construction ma-
terial, such as crushed stone, is generally available for about $2.20
to $3.30 per tonne ($2.00 to $3.00 per ton).
        30, 86, 94, 110, 113,  123,  181,  183
                               -76 -

                     4.3  SECONDARY EXTRACTION
         This technique involves reprocessing mine wastes for second-
ary  extraction of salable minerals.  Most mine wastes contain re-
sidual amounts of the original mineral mined, and usually small amounts
of other valuable minerals.  Extraction of these minerals was either
impossible or economically unfeasible during the original mining oper-
ation. Milling processes have advanced to a point where less pure ores
can be processed.  Mineral economics have also changed, and it may
now be feasible to reprocess some of these mine wastes.

         There are large quantities of coal in many  coal refuse piles
existing  in eastern coal fields.  Hard rock mine tailings in the west
contain significant quantities of heavy metals.  There are two general
methods  of secondary recovery. Wastes can  be transported to active
milling sites and refined using modern techniques, and hard-rock wastes
can be leached in-situ.  Acid is the most common leaching agent.  It can
be sprayed over the pile, then collected  and conveyed to a treatment
facility for recovery.  Normal rainfall can leach large quantities of
valuable  mineral from wastes.
        The value of this technique is purely a matter of technology
and economics.  If secondary recovery can be accomplished economi-
cally, then private industry will eliminate many waste piles. Secon-
dary recovery will probably see widespread use in the future as miner-
als become scarce and mining becomes more difficult.  Advancements
in technology of low grade ore refinement will also boost future use of
secondary recovery.  Western hard rock mine tailings will probably be
a significant area of extensive secondary recovery.
                                -77 -

        Wastes generated during secondary recovery will also be pol-
lution forming, and will have to be disposed in a manner that will con-
trol pollution.

        Secondary recovery from copper and uranium mill tailings is
presently underway.
        Costs cannot be presented. There would have to be a separate
economic  evaluation of each tailings pile to determine feasibility of
secondary recovery.
         14, 39, 94, 110
                               -78 -

                         4.4  RELOCATION
        This technique comprises removal of mine wastes to a more
suitable hydrologic location.  First consideration should be given to
handling the material in place using water infiltration control, regrad-
ing, erosion control, and revegetation techniques.  If the water pollu-
          Originol Ground  Surface
                        Backfilled Ground  Surface
            ; « *;%*;:: *: >: ? s*: >" {^
                                          Impermeable Material
                                          0.9 Meter  (31) Min.
                     >raded Material
                     0.9 Meter (31) Min.
                    CROSS   SECTION  OF
                         Figure  4.4-1
                             -79 -

tion cannot be abated in place, the materials could be relocated, pre-
ferably to a burial location. The basic goal of this technique is to re-
duce contact with oxygen and leaching water, and to stabilize the ma-
terial .
         Direct burial in nearby surface mines is applicable to many
mine waste piles, particularly in the east.  Burial sites are not often
available for hard-rock mine tailings in the west.  Pollution from these
tailings will have to be controlled in place or the tailings relocated to
more suitable locations.

         This technique is generally utilized in conjunction with strip
mine grading where pollution-forming materials are buried and subse-
quently covered at the base of the cut.   This technique has been used
extensively in eastern mining areas to bury acid-producing coal refuse
and acidic  overburden.

         Feasibility of this technique depends on the amount and type of
material to be disposed, the nature of the material, whether it includes
large rocks or debris that may require  special handling, and haulage
distance.  The material must be placed in a favorable hydrologic setting,
where  contact with oxygen and leaching  waters  will be reduced.  The
technique should be  accompanied by other reclamation procedures such
as water infiltration control,  erosion control,  revegetation, and re-
grading.  Pollutant  materials that have  been in place for any extended
length of time may have undergone some degree of natural settling and
consolidation,  thus  making that material much more difficult to remove
from its present site.  Need for burial site acquisition and preparation
is also a factor that may limit use of the technique.  The availability of
suitable cover material could be a limitation.

         A major problem could develop from unsuccessful relocation:
the materials could  continue to produce pollution in their new environ-
ment.  In this case, the site of the water pollution problem has merely
                                -80 -

been moved to a new location, and control has not been accomplished.

         There may be legal problems with landowners who do not want
pollution-forming material transported over or placed on their land,
even if it is adequately handled and buried.  Ownership disputes con-
cerning the pollution-forming material could arise,  particularly if it
has some re-extraction potential now or in the foreseeable future. This
could become a complicated problem, as most mines have changed
ownership many times, with each owner contributing refuse or ma-
terial to the same pile.  This specific situation has  occurred in the
eastern bituminous coal-mining  regions, with regard to bony coal re-
fuse piles.
         Costs for this abatement technique are variable, and depend
on the factors mentioned in the preceding discussion. A general cost
figure for use of this technique is $1 .30/cubic meter ($1 .00/cubic
yard) for haulage and burial and $0.65/cubic meter ($0.50/cubic yard)
for covering the material.  Additional burial site preparation such as
clearing and grubbing, could cost as  much as $742 to $1,235/hectare
($300 to $500/acre).
         2, 9, 22,  44,  111,  112, 146, 149, 181
                               - 81 -

                             4.5  FLOODING
         This technique eliminates oxidation of pollution-forming ma-
terials by inundation which prevents contact with free air oxygen. This
is applicable to most mine wastes,  except those that do not require
oxidation for increased solubility.  The principal chemical pollution
resulting from mining is caused by oxidation of sulfides.  Oxidation
greatly increases solubility, allowing water to leach pollutants.  In-
undation of these types of materials eliminates free air oxygen contact,
greatly reducing oxidation, causing these materials to remain in a
relatively insoluble state.

         Flooding can be  accomplished by transporting the material to
an impoundment or to a burial site that will be inundated.  Dams could
be constructed in  areas of large amounts of waste after consolidating
the waste in the area to be flooded.
         This technique has not been adequately demonstrated to deter-
mine feasibility, but is theoretically sound and could have future use.
Flooding would likely be most applicable for multipurpose use.  Dams
could be created to control water pollution from surface mines if there
were other justifications such as flood control or recreation.

         Initial flooding would release significant quantities of water
pollution until the easily-soluble ions  were leached.  Pollution-forming
materials should remain flooded.  A fluctuating water level in pollution-
forming materials would generate significant quantities of water pollu-
tion. The impoundment would have to be properly  designed to insure
success.  Special legal problems, such as ownership of waste materials,
                                - 82 -

and water rights infringement could arise.  Use of this technique should
be governed by a cost and effectiveness evaluation of this technique
versus other available control techniques.
       Costs would have to be developed on an individual application
                                -83 -

         Underground mine backfilling is a method of disposing of mine
and mill wastes in an underground mine versus deposition on land sui—
face.  This will help to control surface subsidence, mine collapse,  and
reduce water pollution by reducing oxygen contact and stopping erosion.
This practice could free large areas of land now utilized as surface
storage areas for more useful purposes.  Miners have used this method
as an aid to recover pillars, control rock bursts  and roof collapse, and
stoping operations.  Some mine waste is incompetent,,  Cyclone
separators are then used to separate sand and heavies from slime.
Slime is deposited on the surface and the heavy fraction is conveyed
back into the mine.
         The degree of water pollution control resulting from underground
mine backfilling has not been demonstrated.  Use of this technique will
eliminate surface erosion problems occurring at tailings piles.  Oxida-
tion should be reduced, especially if wastes are placed in portions of a
mine that will be flooded after completion of mining.

         This technique should be particularly effective in semiarid
and arid regions  in underground mines that will not discharge.  Under-
ground mine backfilling could be  an  aid in controlling water pollution
from underground mines.  It should help  raise water levels and reduce
the amount of oxygen diffusion through underground mine voids.

         Use of cyclone separators is questionable from a water pollu-
tion control standpoint.  The slurry of fines discharged on land surfaces
                                  84 -

is likely to contain pollution-forming materials,  and will probably be
easily erodable.  These fines could also be unstable due to lack of
larger particulates and could result in landsliding.

         This technique is not universally applicable,  and its use will
be limited by geometry of the underground mine, method of mining, and
physical nature of the waste material.
         It has been estimated that hydraulic placement using available
refuse can be accomplished for about 5% of the cost of mining.  Solid
placement was estimated at 11% of the cost of mining. These costs
would be significantly higher for mines utilizing low grade ores where
most of the volume of material mined is waste.

         The cost of underground mine placement of available refuse
by hydraulic means has been estimated at $0.65 per tonne ($0.59 per
ton). Normal surface disposal of preparation plant waste costs approxi-
mately $0.30 per tonne ($0.27 per ton). Therefore,  underground mine
disposal costs an additional $0.35 per tonne ($0.32 per ton) or about
double the cost of conventional surface disposal techniques. These esti-
mates are based on a hypothetical western Pennsylvania bituminous coal
mine producing 1.1 million tonnes per year (1 million tons per year).
Ref. 176.
         94,  95,  138,  175,  176,  177, 178
                                - 85 -


   5 .0
  - 87 -


                       5.1  METHOD DISCUSSION
        This section discusses techniques used to handle polluted mine
waters by using methods other than chemical treatment, which are dis-
cussed in other sections of the manual.  Techniques described in this
section are applicable to surface and underground mines. Source of the
discharge is  usually not pertinent to use of the technique.

        These techniques are applicable when at-source control tech-
niques are ineffective  or economically unfeasible.   Choice of any water
pollution control technique should be based on the cheapest method that
achieves desired results.  At-source control techniques will reduce,
but will seldom eliminate, pollution from active mines.  Waste water
control techniques or treatment processes are then required to control
remaining pollution.  At-source techniques such as diversion,  infiltra-
tion control,  erosion control and revegetation should be employed where
applicable in conjunction with waste water control to reduce volumes of
water and subsequent pollution.

        These techniques are presented as alternatives to treatment,
which can sometimes be prohibitively expensive.  These techniques
are generally more applicable to active  mining  operations than to aban-
doned mines  because they require continuous operation.  Evaporation
ponds are appropriate to abandoned mines if they are periodically main-
                               - 89 -

                       5.2 REUSE OF DISCHARGE
         This is an effective waste water pollution control technique.
It is often called closed system mining, because water generated during
mining and milling is not discharged.  Water is used in the  milling
operation, passed through a settling pond or clarifier, then returned
to the milling operation.  Water pumped from the mine site is fed into
the  system.

         Large quantities of water are needed in milling and cleaning
operations.  The water is often polluted after passing through the mine
or mill and should not be discharged.  In many cases this water can be
reused with a minimum amount of treatment.

         Basic elements of closed circuit mine systems  are:  1) a col-
lection and conveyance system from the mine to the holding pond; 2)  a
pumping and conveyance system to deliver water from the  holding pond
to the mill; 3)  a conveyance system from the mill to the tailings pond;
4)  pumping and conveyance from the tailings pond to the holding pond
(treatment may be required in this system).  A sump area in an active
deep mine can be  utilized as a holding  pond.  Adjacent inactive deep
mines could  be utilized as a tailings pond.
         Reuse of discharge is especially applicable in a low rainfall
region where available water is at a premium.  In high rainfall areas
of the east, there is often more mine water than can be utilized.

         Water quality is a severe limitation.  Most suspended solids
can be eliminated in settling ponds, but chemical constituents  can render
                               - 90 -

To Preparation
Plant or Return
to Mine  Site




"WTfn lof 	
—TLUJ lei 	









• \
  ~^_  	Overflow^.	|	1	
        Treatment Plant
      Settling Pond
Mine Water
         Discharge to Stream
                                             Top Water Level
                                Inlet placed at down hill end to
                                encourage deposition of coarse
                                particles and improve strength
                                of deposit at  A against main

                REUSE  OF   DISCHARGE
                         Figure 5.2-1
                            - 91  -
                                          Adapted from  National
                                          Coal Board .Great Britian

water unfit for milling use.  Chemically degraded water is not accep-
table for use in some ore refinement processes.  The water can be
used as long as possible until its quality is such that it must be disposed
or treated.  This rejected water can be disposed by evaporation, spray
irrigation or deep well  injection.

         A closed circuit mining/milling system must have capacity to
store large quantities of water during peak flow periods.  Underground
mines are not as quickly affected by heavy periods of rainfall as are
surface mines. Some of this effect can be reduced by using water
diversion techniques  around a mine area.  A storage system of proper
capacity can be designed using knowledge of local weather extremes
and water needs of the operation.

         One advantage of non-discharging, closed circuit, mining
operations is that a discharge permit is not required.

         This technique may be particularly useful in hydraulic mining.
The sediment load could be settled out in large ponds and the water re-
used for further mining.  This would be expensive, but it might  be a
way to satisfy discharge limitations on settleable solids In water quality
         Costs would have to be developed on an individual application
         2, 7, 9, 16, 17, 28, 34,  38, 97, 116, 122, 138, 151, 155
                                - 92 -

                      5.3  EVAPORATION PONDS
         Large holding ponds may be used to prevent discharge of pol-
luted water by means of evaporation.  Mine discharge can be collected
and conveyed to a large holding pond or series of holding ponds.  The
system should be designed to provide that all mine water is lost to the
atmosphere through evaporation, and no discharge occurs.  The bottom
of the pond should be lined where impoundment materials are perme-
able.  Clay liners may be useful because of their ability to adsorb pol-
lutant-forming chemicals,  such as arsenic compounds.
                                     -—Surface  Mine Discharge
                 Retention Basin
                                                  Return Line
         Discharge Control
                                          Pump Line
                              Outflow Channel

                                         Receiving Stream
                          EVAPORATION  POND
                              Figure 5.3-1
                                - 93 -

         The system must be designed for capacity flow during periods
 of high rainfall and tow evaporation rates.  Low evaporation rates in
 winter will have to be considered.  The amount of water to be evaporated
 could be reduced by using diversionary measures.  Settled solids will
 have to be removed from the pond periodically in order to maintain pro-
 per capacity.
         Evaporation ponds could be a good water pollution control
 technique, but their use as a sole water pollution control device is re-
 stricted to arid or semiarid  regions.  Rainfall must be less than evap-
 oration rates to facilitate operation.  The system must also  be capa-
 ble of handling short term adverse conditions of high rainfall and low
 evaporation  rates to be fully  effective.

         Oversize holding ponds could be used at a mine site to induce
 partial evaporation loss of water, which would  decrease the volume
 requiring chemical treatment.

         Design of an evaporation system would  require detailed investi-
gation of mine hydraulics and local weather conditions.  Careful design
would also be required  to prevent leakage from the ponds  that would
pollute ground water.  Any impoundment structure should be  equipped
with emergency,  noneroding overflow spillways  to prevent the devasta-
tion that would accompany a breach of the impoundment sides.

         Requirement of periodic maintenance is a limitation of the use
of evaporation ponds.  Often a pit, whether lined or not, must be ac-
companied by monitoring wells to check seepage.

         This technique appears viable theoretically, and  warrants
further research and demonstration.
                                - 94 -

         The cost of grading and compacting pond dikes ranges from
$0.45 to $0.85 per cubic meter ($0.35 to $0.65 per cubic yard).  Lin-
ing costs depend on materials used, availability and area covered.
Clay liners, for example, can be placed for approximately $2.30 to
$7.80 per cubic meter ($1.75 to  $6.00 per cubic yard)  including  ma-
terial and installation.
        2, 7, 9,  16,  17, 28, 34, 38, 116, 138, 151
                                - 95 -

                       5.4 SPRAY IRRIGATION
         Spray irrigation can be used as an effective mine water dis-
posal technique.  Mine water is collected and distributed over a large
land area.  This technique will find most use in irrigating regraded
surface mined lands in arid and semiarid  regions.  The water must
not be toxic to vegetation and must not contain excessive concentrations
of sodium or soluble salts that will result in long-term soil  or spoil
degradation.  Treatment may be required to eliminate these elements.
         Spray irrigation has been used for disposal of treated sewage
water, but it has not had application in mine water pollution control.
There are many problems involved in its use, but they will eventually
be overcome.  Use of the technique should be carefully regulated to
prevent ground and surface water pollution.

         The technique could likely be used with polluted water if ap-
plication rates do not exceed vegetative and evaporation losses.  Soil
and ground water analysis should be routinely performed at spraying
areas.  Buildup of pollutant-forming elements would require periodic
relocation to new spray sites.  This technique could be used to establish
vegetation in low rainfall  areas.   However, the amount of discharge
from low rainfall areas will be small,  and may not justify use of the

         The references listed with this technique should be consulted
for further information on system design and function.  These papers
also detail precautionary measures to prevent pollution from spray
                                - 96 -

        Costs will have to be developed for each application of this
        122, 125, 150, 169, 181,  196
                             - 97 -

         Subsurface waste injection is a means of disposing of liquid
wastes in underground reservoirs.  Vertical boreholes are drilled and
cased to permeable zones.  Liquids are introduced  by gravity feed  or
by pumping.

         Reservoir investigations are required prior to selection of a
disposal site.  An acceptable aquifer must be well below potable water
zones.  It must be confined by aquitards to prevent  migration of the
waste to potential water supply aquifers or to the surface.  Feasibility
test borings, water levels, and pumping tests  are used to determine
aquifer characteristics and suitability for disposal.

         Subsurface waste injection has been widely practiced in the
oil fields of Texas and Louisiana.  Chemical processing, pharmaceutical
and heavy metals industries have been using this method with increas-
ing frequency.  New discharge regulations may encourage future use of
this technique,which may be cheaper than  chemical  treatment of waste.

         Well casings should be cemented in place to prevent vertical
migration of the waste.  Casing material should be  corrosion resistant.
         The environmental impact of subsurface injection has not been
fully explored.  It can be a dangerous technique that merely transfers
a surface water pollution problem to a potential ground water pollution
problem. Very few aquifers are sufficiently contained to insure against
migration.  Many aquifers may have already been breached by explora-
                               - 98 -

tory boreholes.  The possibility exists that a storage aquifer could be
needed as a future water supply as water demands increase.

         The potential disposal aquifer should be thoroughly evaluated
to insure against ground water pollution.  Boreholes and casings should
be adequately designed to guard against failure, which could result in
pollution of water supply aquifers.

         The disposal system  must be properly designed to insure that
it functions effectively.  A disposal aquifer must have sufficient perme-
ability to accept the amount of flow required.  Suspended solids must
be removed to prevent clogging of the aquifer,  thus decreasing  its
permeability.  The chemical nature of an aquifer should be analyzed
with respect to the waste. Chemical reactions involving precipitates
could clog  an aquifer.  For example:  slightly acidic, high iron solu-
tions should not be disposed into a carbonate aquifer, because precipi-
tated ferric hydroxide could clog the pores, unless the discharge is to
a large solution opening.

         Abatement  of ground water pollution is much more difficult
than abatement of surface water pollution.  Severe ground water pollu-
tion is a problem future generations could  inherit from subsurface waste
injection.  There may be little renovation of waste in a ground water

         There is very little legislation controlling subsurface waste in-
jection.  Adequate protective legislation should be proposed and enacted.
         A rule of thumb for drilling costs would be about $1 .30 per
centimeter diameter per meter of well ($1 per inch of diameter per
foot of depth).   Deeper wells will cost much more. Cementing the cas-
ing will be an additional expense.  If the waste is corrosive to the
standard steel casings,  then additional expenses will be incurred for
noncorrosive casing.   Costs of related facilities such as holding ponds,
                               - 99 -

piping and pumps will have to be determined for each application.
         100, 209
                               - 100 -

                    5.6 REGULATED DISCHARGE
         This technique is based on the variable nature of surface water
quality and quantity.  Water quality of streams is continually changing
and their volume of flow is highly variable. Most streams have an as-
similative capacity so that they can receive a certain amount of mine
waste without adverse effects.  The amount of material a stream is
capable of assimilating is highly variable,  depending on flow and water
quality.  In  cases where the pollution would be discharged in any event,
it would  be beneficial to control the effects with  this technique.

         Mines, particularly deep mines, have less variation in their
flow and discharge pollutants throughout the year.  A receiving stream
may not  be capable of assimilating large quantities of pollution during
low-flow periods, yet mines continue to discharge.  Some streams are
capable of assimilating the mine discharges for  all but short periods
during the year.   However,  it is these periods when fish kills can occur.

         This technique requires releasing mine water only in amounts
that the receiving stream  is capable of assimilating at any given time.

         The system is comprised of holding ponds capable of storing
large quantities of mine water during periods of low assimilative ca-
pacity.   The ponds are drained during periods when the stream is cap-
able of accepting the waste water.

         The technique could be effectively utilized with flood control
dams on polluted streams.  These dams could store flow when down-
stream reaches of the river are not capable of accepting water for re-
lease during more appropriate periods.  Installation of a strategic dam
on a polluted stream in an otherwise marginal water quality river
system could be capable of controlling adverse pollution effects in  an
entire river system.
                                - 101 -

         The discharge would have to be continuously regulated, based
on continuous water quality measurements and flow monitoring of the
receiving stream.
         The concept of purposeful discharge of polluted water to a re-
ceiving stream seems to be a negative approach.  However, the tech-
nique may be attractive in areas (particularly with respect to  abandoned
mines) where other abatement is ineffective or unfeasible.

         A complete hydrologic evaluation of the area would be required
for design of this system.  Variabilities of water quality and flow in the
receiving stream would have to be well documented.  The storage fa-
cility would have to contain sufficient capacity to  hold the largest quanti-
ty of water expected.  A computer program could be developed to handle
the mass of data and  establish the design parameters.

         It should be  emphasized that dilution effect achieved  through
regulation of discharges is not a substitute for adequate treatment.
Use of this concept should be regarded strictly as an interim  measure.
         Costs are not available.
         2, 4, 7, 8, 37, 47, 66, 97, 112,  116, 138, 169
                                - 102 -

                            5.7  REROUTING
        This technique involves collection of mine waste water and
conveying it to more suitable discharge points. Mine water can be
conveyed from one watershed to another, more suitable watershed,
by use of drainage tunnels as explained in  the Underground Mining -
Waste Water Control section.

        This technique can be applied where mine water is polluting
upper reaches of a watershed but where lower reaches are largely un-
affected.  Mine water can be collected at a point of discharge for piping
or channeling to a downstream point, where  it can be assimilated with-
out adverse affects.

        This technique can be effective where a particularly desirable
body of water is being polluted.  Upstream discharges could be col-
lected and conveyed past  an impoundment or other desirable stretch
of water and discharged back into a stream.

        This technique was applied with notable success at Cold Stream
Dam, Phlllpsburg, Pennsylvania.  This impoundment was being polluted
by several upstream deep mine discharges.  The  discharges are essen-
tially uncontrollable and, at any rate, funds  were not available for a-
batement.  Fortunately, the discharges are all on the same side of the
stream. Water quality upstream of the discharges Is good. A diver-
sion ditch was constructed along the side of the valley to collect and
convey the discharges around the impoundment. This diversion ditch
discharges to the stream directly below the dam.  No pollution was
abated, but the impoundment was returned to usefulness.  It is present-
ly used for swimming and it is on the Pennsylvania Fish Commission's
approved trout stocking list. The stream  itself is incurably polluted
by abandoned mine discharges  below the dam, and is tributary to Mo-
shannon Creek, another grossly polluted stream.
                               - 103 -

         This technique is designed for interim use where presently
incurable water problems exist,  particularly from abandoned mines.
The water problems may be presently incurable either for reasons of
lack of developed technology or lack of funds to effect the cure.
         Though this technique does not abate pollution, it can signifi-
cantly reduce adverse affects of pollution.  In many easels, this tech-
nique can be effective and cost less than available at-source control
techniques of questionable effectiveness.

         This technique could be used successfully in many areas.  Re-
routing should be considered as a viable tool for use in water pollution
control planning.  Its use, however,  should be intended as an interim
measure pending funds availability or suitable at-source abatement
         Costs are not available and would have to be developed for
each situation.  It is expected that costs of rerouting can often be less
than use of other techniques.
                                - 104 -

                      5.8  MINERAL RECOVERY
         This technique involves the recovery of valuable minerals,
particularly heavy metals,  by chemical treatment of existing mine dis-
charges.  Heavy metals are precipitated by neutralization.
         This technique is theoretical and there are no known applica-
tions.  Many mine discharges have high concentrations of valuable
minerals.  Economic evaluations would have to be performed to deter-
mine if a recovery plant would be profitable.  This technique could be
utilized to  offset the cost of treatment plants constructed by govern-
ment agencies.  Much research and demonstration would be required
to develop  this technique.
         14, TREATMENT Section of this REPORT,
                               - 105 -


     6 . 0
   - 107 -


                       6.1  METHOD DISCUSSION
         Regrading, as applied to surface mining, is mass movement
of earth to achieve a more desirable land configuration.

         Surface mining usually involves removal of large amounts of
overburden in order to expose a mineral.  Historically, this overburden
was commonly placed  in the handiest location, at the angle of repose of
the material,  with little thought given to future regrading. The result
has often been large open pits, large ugly, unstable  spoil piles, heavy
erosion, landsliding and water pollution.

         New  mining laws are requiring that this spoil be placed
back in the mine pit and regraded to a desirable shape.  There is waste
material at all surface mining operations, and some sort of beneficial
regrading can be performed after mining.

         This  section discusses various types of regrading available
for use on surface mined lands.  The techniques vary only according
to the geometry of the final land surface.  Regrading is the most essen-
tial part of surface mine reclamation.   It cannot be considered a total
reclamation technique.  It must be used in conjunction with other tech-
niques described in this manual.

         The purpose of regrading is manifold:

         1)  aesthetic improvement of the land surface
         2)  returning the land to usefulness
         3)  providing  a suitable base for revegetation
         4)  burial of pollution-forming materials
         5)  reduce erosion
         6)  eliminate  landsliding
         7)  encourage  natural drainage
         8)  eliminate  ponding
         9)  eliminate  hazards, such as high cliffs,
            deep pits and deep ponds
        10)  control water pollution
                               - 109 -

         Regradlng at an active mining operation is an entirely different
matter than regrading abandoned mines.  Regrading should be required
of all active surface mines.  A regrading plan can be developed during
the preplanning stage, and mining can proceed in a manner conducive
to regrading requirements.  Spoil can be placed initially so that regrad-
ing is simplified,  such as Modified Block Cut Mining.

         Regrading is often more difficult in old abandoned surface mines
because the spoil was placed without considering future regrading.
Contour strip mines in steep terrain create special problems where
spoil was thrown over the outslope and is difficult to regrade.  It is
difficult to achieve a suitable surface for revegetation  on abandoned
mines  because spoil segregation was rarely practiced. The  soil is
generally lost,and pollution-producing  materials are well mixed through-
out the spoil.

         Regrading should be performed in conjunction with:

         1)  spoil segregation
         2)  burial of pollution-forming materials
         3)  spreading soil if available
         4)  construction of water diversion facilities
         5)  sealing of underground mine openings or auger
            holes  in the  highwall
         6)  soil supplementation and revegetation

         In some forms of mining such as open  pit or quarrying, there
is little overburden to regrade.  However,  the mine could be reshaped
to reduce pollution and soil could be spread and  revegetated.

         Choice of a regrading technique will depend upon many variables,
such as:

         1)  funds  available
         2)  future land use
         3)  degree of water pollution control required
         4)  terrain
         5)  geometry of the spoil with relation to geometry
            of the mine
                               - 110 -

         6)  amount of spoil
         7)  highwall height and length
         8)  legislative requirements
         9)  leasing stipulations

         Costs of regrading techniques are quite variable.  The report
Analysis of Pollution Control Costs written for the Appalachian Region-
al Commission by Michael Baker,  Jr.,  Inc. is a good cost reference.
Regrading costs are usually based on the amount of earth to be moved.
The cost per cubic meter is also highly variable and depends on local
conditions.  Approximate cost ranges are given where appropriate.
Costs are also dependent upon the agency performing the work. An
active miner can place spoil piles so that regarding is simplified, and
he has the necessary equipment immediately available at the site.  Re-
grading in conjunction with active mining is much cheaper than regrad-
ing abandoned mines.

         Effectiveness of regrading is dependent on the effectiveness of
other techniques applied in conjunction with regrading.  Each grading
project should be designed using sound water pollution control princi-
ples.  The mine should be evaluated with regard to  basic causes of
water pollution.  A regrading plan should be designed to correct any
deficiencies.  Effectiveness of a regrading project is often indicated
by vegetative cover and runoff characteristics.  Actual effectiveness
hinges on the amount of water pollution reduction.

         Legal problems often arise in regrading abandoned mines.
There is often mineral remaining behind a highwall that was not eco-
nomically extractable at the time of mining.  This mineral may be
economically mineable in the future.   Regrading usually makes re-
maining mineral more difficult to extract.  Mineral rights owners
often balk at permitting regrading operations at abandoned mine sites
for this reason.

         Extensive documentation of relative effectiveness of various
regrading methods does not exist.  An adequate foundation of data to
compare effectiveness of one technique with another is needed.  Com-
parisons of regrading techniques effectiveness are primarily based on
theory and some demonstration projects, but have not been proven.
                               - 111 -

                            6.2  CONTOUR
        This technique involves regrading a mine to a shape that close-
ly resembles original land contour. It is generally one of the most
favored regrading techniques because  it returns the  land as closely as
possible to its pre-mining state.  This technique is also favored be-
cause all spoil is placed back into the  mine   resulting in less  disturbed
area, and usually less water pollution.  Contour regrading facilitates
deep burial of pollution-forming material.  It reduces erosion due to
reduction  in size of disturbed areas.
            Original Ground  Surface
          Diversion  Ditch
                               ^Xr- Backfilled Ground  Surface
                         Pit  Floor
                       CROSS   SECTION  OF
                  TYPICAL  CONTOUR   BACKFILL
                             Figure 6.2-1
                                               Adapted  from  drawing
                                               in reference  No. 61
                               - 112 -

         Contour regrading appears to be one of the best methods of
water pollution control for surface-mined lands.  It is also one of the
most expensive, because of the large volume of spoil to be moved.  It
can be facilitated through use of mining techniques such as the modified
block cut.

         Contour regrading is difficult at abandoned strip mines in
steep terrain.  It is difficult and expensive to move downslope spoil
back upslope onto the bench.

         Contour regrading is limited to areas where sufficient spoil
exists to achieve original contour.  It is not applicable for  mining recla-
mation where there  is a  large volume of mineral in relation to the
volume of overburden, as in open  pit or quarry mining.

         Contour regrading is believed to be a most effective and aes-
thetically pleasing regrading technique.
         Contour regrading will generally cost between $1240 and
$6180 per hectare ($500 to $2500 per acre).

         9,  33, 60, 61, 70, 145, 146, 148, 149, 166, 173
                               - 113 -

                           6.3  TERRACE
        Terrace and pasture regrading are similar in appearance and
provide similar degrees of pollution control. They are discussed to-
gether in this section. Terrace regrading creates a gently sloping
bench over a strip mine cut and results in a steep outslope beyond the
mined area.
        •Diversion Ditch
               )riginol Ground   Surface
                        •Backfilled Ground Surface

                               Slope Away From Highwall

               CROSS  SECTION   OF
                       Figure  6.3-1
                                            Adapted from  drawing
                                            in reference No.  61
                            - 114 -

         Terrace regrading generally involves less earthmoving than
contour grading, but more than swale regrading.  It is useful in areas
where the need for flat land is dictated by the potential future land use.
It has been used principally in steep terrains where contour regrading
is very difficult.

         This technique has been used frequently.  However, its water
pollution control abilities are often less then desirable.  Steep slopes
at the highwall and at the outslope tend to encourage erosion.  The
steep outslopes of spoil material are often subject to landsliding.  The
gently sloping bench, on the other hand, does not encourage quick run-
off and causes increased infiltration.  Spoil is not confined to the mined
area as in contour regrading, resulting in a larger disturbed area.  The
larger the disturbed area, the greater the erosion potential.  Stockpiled
topsoil must be spread thinner because of the larger disturbed area.
Revegetation will be more costly because of the larger area, and is
often difficult on the unstable  steep slope areas.

         Erosion and landsliding  can be reduced by compaction and re-
vegetation of the steep slopes.
         Terrace regrading costs range from $500 to $4,940 per
hectare ($200 to $2,000 per acre).
         9, 33, 60, 61, 126, 135, 145, 146, 148, 149, 166, 173
                                - 115 -

                             6.4 SWALE
        Swale regrading is used to describe various similar techniques
that result in similar land configuration.  Included with this discussion
are:  1) Georgia V-Ditch; 2)  Swallow Tail; 3) Reverse Terrace; and
4) rounding of spoil  piles.  Swale  regrading is used to minimize earth-
work in contour strip mine regrading.  A smaller amount of spoil is
moved from the low wall to the highwall (compared with contour and
terrace regrading techniques).  Much of the spoil is left: in its present
position.  Grading is performed to create positively draining swales
that collect and convey water from the mine.  Grading is also performed
to cover the mineral seam and pit floor, and to reduce steep spoil slopes,

            -Diversion  Ditch

            •Original  Ground Surface
                                                    Ground  Surface
                     CROSS  SECTION  OF
                 TYPICAL   SWALE   BACKFILL
                           Figure 6.4-1
                                                Adapted from drawing
                                                in reference  No.  6L
                              - 116 -

        Older applications of this technique such as "rounding of spoil
piles and covering the coal seams" were mainly ineffective.  Newer
techniques utilizing  more extensive grading, sound engineering design,
and dependence on corrollary abatement techniques are much more ef-
fective .

        The purpose of this technique is to minimize reclamation costs
while providing water pollution control.  Swale regrading is not as aes-
thetically pleasing as contour regrading.  Upper portions of a highwall
are left exposed,  and a regraded surface is generally uneven.
     ^Original  Ground  Surface
          -Diversion Ditch
                                      Backfilled  Ground Surface
                     CROSS   SECTION
                           Figure 6.4-2

 Adapted from drawing
 in  reference No. 61
                              - 117 -

         Swale regrading usually conveys runoff from a mined area
faster than other techniques.  Slopes are generally steeper, and the
low points, or swales, if properly located,  collect rainfall quickly and
concentrate it in a flow channel where less infiltration will occur than
if this water was distributed over a wider area.

         Effectiveness of swale regrading is dependent on establishing
a dense ground cover of grasses, legumes and shrubs.  Its  effective-
ness is further controlled by 1) proper location of swales; 2) correctly
designed swale gradients  capable of conveying water; 3) water diversion
ditches; 4) elimination of impoundments and; 5) burial of pollution-form-
ing materials.
              -Original Ground Surface
                 -Diversion Ditch
                           Backfilled  Ground  Surface
                                           Original  Ground
                          CROSS  SECTION  OF
                               Figure 6.4-3
Adapted from drawing
in reference  No. 9
                                - 118 -

        Costs of swale grade average $500 to $3,700 per hectare ($200
to $1,500 per acre).
        9, 60, 61, 72, 135, 145,  146, 148, 149, 166,  173, 179, 181
                              - 119 -

                                6.5 AREA
         Area mining often results in large disturbed areas that re-
semble gigantic washboards.  The mined area is composed of ridges
and valleys of spoil material.  The final cut is usually left open and
often contains a pond bounded by a highwall.

         Contour regrading of area mines is a relatively simple matter
by comparison with reclamation of contour mines.  Existing spoil
ridges are pushed into adjacent low areas until the entire mine is
smooth, and resembles the initial  land shape. These slopes are often
gentle, and erosion is controlled by establishment of a vegetation cover.
The surface should be graded to provide for positive drainage, and pol-
lutiornforming  materials should be buried during regrading. The dis-
posal of spoils must be conducted with equal regard for vegetation and
shallow aquifers.

         Surface coal mining in western United States has been pri-
marily accomplished by the area method.  Regrading is less expensive
in terms of cost per ton of coal produced in the west because of low
overburden to coal ratios. Regrading to a suitable land form can be
more difficult in the west due to large amounts of coal extracted and
subsequent lack of fill material.
        Area mine regrading and subsequent revegetation has proven
effective in Illinois coal fields.  It can return the land to a configuration
useful for agriculture,  silviculture, development and recreation.

        Effectiveness is  dependent on establishment of vegetation and
runoff characteristics of the regraded surface.
                               - 120 -


         Costs generally fall In the range of $1240 to $4940 per hec-
tare ($500 to $2000 per acre).
         56, 61, 72, 166, 179
                                - 121 -

                           6.6  OPEN PIT
         Open pit mining is a major form of surface mining.  It can be
differentiated from strip mining by the relatively small amount of over-
burden removed in relation to the total amount of mineral deposit  removed.
Strip mining usually requires removal of large amounts of overburden
to recover a relatively small amount of mineral.

         Open pit mining is used extensively to recover minerals that
occur  in massive, usually near-surface deposits such as copper,  hema-
tite, taconite, and phosphate.  Most open pit mining is done for the re-
moval  of building products such as stone, sand, gravel and clay.  These
open pit mines are generally termed quarries,  and  can be found near most
population centers throughout the  country.

         Open pit mining begins by stripping off the soil and overburden
to expose the deposit.  The mineral is then removed and is transported
to a processing area.  In the case of building materials, there is little
waste  material after processing.  Processing of ores, such as phos-
phate and copper, produces tremendous amounts of waste material.

         Open pit mines generally present fewer water pollution problems
than the other forms of surface mining. There is some chemical  pollu-
tion associated with ore mining, such as the copper and iron industries.
As a general rule,  open pit mining results in physical pollution (sedi-
ment)  rather than chemical. Open pit mining often  results in a large
enclosed hole in the earth.  These pits will sometimes fill with water,
however, seldom have a surface discharge.  As such,  most abandoned
open pit mines are not sources of water pollution.  Active open pit
mines  are more likely to be sources of pollution because of the necessity
for pumping accumulated water from the pit. It is expected that these
active  mines will not be pollution  sources after implementation of Fed-
eral and State discharge requirements.
                               - 122

         Although most open pit mines do not have a surface discharge,
it is likely that most of them act as ground water recharge basins. The
pits collect some surface runoff and direct rainfall. If the pit does not
have a discharge, then this water is being lost to the atmosphere via
evaporation and/or to  the ground water reservoir.  Ground water pollu-
tion is likely to occur  in cases of contaminated pit water. The nature
and extent of ground water pollution from open pit mines is largely

         There are some documented cases of reclamation of abandoned
open pit mines.   These cases were primarily where reclamation was
performed to return the mine to a higher than original land-use category,
which produced a profit to the landowner.  The pits are usually left open
and the removed  overburden is abandoned wherever it was stockpiled.
Revegetation has been primarily voluntary.

         There are several reclamation and abatement techniques that
can be used to control water pollution from open pit mines.  Water di-
version ditches can be used where surface  runoff is entering the mine.
The disturbed area around the mine can usually be graded and planted
to reduce erosion.  Milling wastes can often be placed back into the pit
for regrading and revegetation. Soil can often be stockpiled at the be-
ginning of mining and subsequently regraded around the disturbed area
for establishment of vegetation and control of erosion.  General regrad-
ing  of the pit is sometimes applicable. Regrading can be utilized to
stabilize steep slopes  or to sculpt the area into a more usable form.
The pit could also be developed so that it would fill with water after
abandonment. This would be particularly useful for controlling chemi-
cal  pollution resulting from oxidation.  Impoundments in the pit are also
useful  as settling basins to reduce sediment discharge. Water passing
over erodable material could be directed into the pit impoundment prior
to discharge.
         Some degree of reclamation can be performed at most open pit
                                - 123 -

mines. Stockpiling of soil would be applicable in most instances.  Wa-
ter pollution problems from tailings piles associated with open pit mines
can often be alleviated by grading the tailings into the pit.  This would
probably require that ore reduction be performed in close proximity to
the pit. It would also  require the use of a mine development plan that
would allow placement of the waste concurrent with mining.  This is not
possible in all cases.  The amount of earthwork involved in returning
the tailings to the pit would be very expensive in many operations, such
as the large open pit copper mines. Regrading is also limited when
mining hematite and building products, where most of the material is
removed from the mine site.

        There is a wide variability among open pit mining operations
and associated pollution problems.  As such, there are no general rules
of thumb that can be used to control pollution.  The mines must be treated
as individual cases. The water pollution impact should be determined
for each site. Water pollution control techniques could then be prescribed
for each mine site to correct or alleviate the problems of that particular
         General costs are not available and depend on the requirements
of the individual mine.
        10, 15, 86, 112
                               - 124 -

                           6.7 HYDRAULIC
         Hydraulic mining is performed by the application of a high
velocity stream of water against an unconsolidated alluvial or colluvial
deposit. The water is used to break up and wash away the unconsolidated
deposit. The resulting mixture of water and sediment is then passed
through a flume to recover gold.  Hydraulic mining is used primarily
for gold mining in Alaska, but its usage may spread if gold prices re-
main high.

         The water quality impact of hydraulic mining is severe.  It
leaves a scarred landscape composed of unstable embankments of uncon-
solidated material.  It also discharges a tremendous sediment load into
the receiving stream.

         The post-mining landscape could be regraded into a more stable
and suitable shape for erosion control.  Revegetation would also aid in
reducing erosion.  The types  of materials mined by hydraulic methods
are highly erodible and some  type of stabilization is required.

        Sediment catchment  basins should be used for future hydraulic
mining operations.  These basins will fill quickly and should then be re-
graded and revegetated.  Use of settling basins would likely require a
continuous effort to regrade filled ponds and create new ponds.
         Reclamation of hydraulic-mined areas has not been well docu-
mented,  and it is doubtful if significant restoration has been attempted.
Reclamation is required if the sediment loads from hydraulic-mined
lands are to be reduced.  Standard regrading and reclamation practices
                               - 125 -

would apply. Species for revegetation would have to be selected for the
climate of the mined area.  Revegetation may be difficult in some of the
primary hydraulic-mined areas in Alaska because of climatic extremes
and a relatively fragile environment.
         Costs are not available.
                               - 126 -

                             6.8  DREDGING
         Dredge mining is a surface-mining method that involves the
removal of ore or gravel  from under water.  Mining  is usually per-
formed from floating dredges using mechanical or suction recovery.
Dredging is performed at an existing body of water, or performed on
land from an artifically created pond by excavating below the water

         Dredging operations for the  removal of building products,
such as sand and gravel,  usually result in a water-filled pit.  Regrading
Is only required for any disturbed land above  the water table.

         Dredging is also used for the recovery of precious metals,
particularly gold.  The small amounts of metal are removed  and most
of the material is then disposed near the mine site.  These large  a-
mounts of material should be regraded and revegetated, unless they
are disposed below water level.

         Grading can be accomplished during  the mining operation.
Dikes can be constructed  to isolate the operation from adjacent streams
or lakes in order to contain the large sediment loads within the mined
         Documentation of dredge mine reclamation could not be found,
but specific instances of reclamation were reported.  The mined area
can be regraded around impoundments, thereby returning the area to
recreational usage.
                               - 127 -

         Costs are not available, and are dependent on the physical
characteristics of the mined area.
         174, 202, 203
                               - 128 -

                          6.9  AUGER
        Auger mining is performed by drilling large holes, up to 2.3
meters (7 feet) in diameter, into the face of a coal seam.  It is usually
performed from the bench of a contour strip mine to produce coal
from behind the highwall where further strip mining is uneconomical.

         -Original Ground  Surface

             Diversion Ditch
                                                Original Ground
          Compacted  Impermeable"

         CROSS   SECTION  OF
              Figure 6.9-1
                                               Reference No. 135
                             - 129 -

         Auger holes must be sealed after mining to stop drainage or
to reduce contact with free air oxygen.  Many techniques have been
utilized to control pollution from auger-mined areas.  Sealing indi-
vidual auger holes with various types of impermeable material has been
attempted.  These are described in the Underground Mining - Mine
Sealing section of this report.

         Auger mine sealing is  also accomplished by grading  earth a-
gainst the exposed holes and the highwall.  Construction of a clay liner
against the highwall is an effective sealing technique.  Less costly
methods using compaction of a spoil barrier or simply regrading a
strip mine over the  auger holes have been employed.

         Choice of method is partly dependent on the dip of the coal
seam.  This will determine the amount of water pressure that will
ultimately be exerted at the seal.  Complete inundation of the augered
area is desirable.  However, this  is often impractical or economically
unfeasible.   Regrading techniques serve to partially (and sometimes
completely) flood the holes,  and decrease oxygen availability.

         A clay liner can be constructed by compacting layers of clay
against the face of the highwall, beginning from a slot excavated in the
underclay.  The layers should be  relatively thin, 0.3 to 0.6 meters
(1 to 2 feet), in order to be effective. The layer is placed and then
compacted with rollers or by passage of heavy equipment. Compaction
tends to force the clay into the auger holes and into cracks in the high-
wall, causing a tight seal.  Acquisition of clay is often pronibitively
expensive, and the least permeable material on-site is genereilly used
to form the liner.  This can be effective If on—site material contains
a high percentage of clay and a low percentage of rock.
         There has not been sufficient documentation to provide a basis
for comparison of the various regrading sealing techniques.  Clay liner
should be the most effective, followed by compaction of on-site materials,
The least effective technique would be standard strip mine backfilling.
                                - 130 -

         Problems occur in areas where auger mines have broken Into
the downdip side of adjacent deep mines.  Sealing of auger holes in this
instance could cause extensive inundation, and produce large water
pressures on the seals.  If the water has  no alternate route and con-
tinues to build up pressure, the seals will be breached and seepage
will occur.  Physical blowouts  are minimized if the strip mine is
backfilled over the sealed auger holes. Leakage caused by excessive
heads of water does not signify lack of success: any inundation that
occurs can result in at least partial control of pollution.
         Costs of constructing clay liners may be $2.30 to $7.80 per
cubic meter ($1 .75 to $6.00 per cubic yard).  Other abatement costs
depend on the requirements of the specific mine.
         61 , 67, 135
                               - 131 -

                         6.10  HIGHWALL REDUCTION
          Highwall reduction is not a singular pollution control technique.
It  is often used in conjunction with regrading and total reclamation.  The
last cut of a strip mining operation usually leaves  a vertical or near
vertical face consisting of in-place overburden.  The top edge or lip of
the highwall can be removed by grading or blasting.  This  material can
then serve as fill  in the cut.  The angled  slope reduces the hazard  of an
exposed cliff and falling  rock, and can improve aesthetics.
                                      Original Ground Surfaces
                           Angled Blosthole-^.
                    Ground  Surface
                  Spoil Material


                                             '-Mineral Seam
                               45° BLAST  METHOD
                                     Original Ground Surface
                           Vertical Blastholes-
                     Ground Surface
                    Spoil Material
                               25° BLAST  METHOD
                                                  Mineral Seam
                              HIGHWALL  REDUCTION
                                   Figure 6IO-I      Adapted from drawings
                                                 in reference No 60
                                    - 132 -

        This technique is only applicable for use with grading plans,
such as swale or terrace, where the highwall is exposed.

        Highwall reduction is also applicable to quarries and open pit
mines.  It can be used to help return the land to usefulness, eliminate
cliffs, and provide fill for the pit.
         The main function of highwall reduction is to increase safety
and improve aesthetics.  It has only limited use in water pollution con-
trol.  Slope  reduction will  increase stability and decrease erosion
from a highwall composed of unstable materials.  It can also provide
fill, but  availability of fill material is not usually  a problem.

         Its erosion control values may also be limited.  Most high-
walls are composed of fractured rock which spalls off the face during
periods of freeze and thaw.  Exposed rock seldom produces  sediment
unless the rock is easily weathered.  Sandstones with easily weathered
matrices occasionally occur and can cause erosion problems.  High-
wall reduction and subsequent revegetation can control sediment pro-
duction from erosion-prone highwalls.
         Costs for this technique are variable due to the variation in
desired final angle of the highwall, and the amount of additional re-
grading that may be needed.  The cost will range from $27 to $44 per
linear meter ($25 to $40 per yard) along the highwall.
         60,  61
                                - 133 -

                        6.11  SLOPE REDUCTION
         This technique  is used to stabilize and reclaim downslope
spoil material resulting from contour strip mining in steep terrain.
Its purpose is to render the slope more resistant to erosion and
sliding.  There  are two  (2) generally accepted techniques of slope re-
duction;  one called the "7° Storage Angle" and the other known as the
"Parallel Fill".

         The 7°  storage angle essentially limits the lower half of the
downslope to a maximum angle  of 7  greater than the angle of original
ground slope. The parallel fill differs only slightly. It provides for
the material to be stored parallel to the original  ground line, and is
built up in compacted layers, usually about 0.9 meter (3 feet) deep.
The  depth and angle of spoil  material is determined by soil conditions
of the existing slope and type of spoil material.   Both techniques dis-
tribute the overburden over larger than normal areas.

         Slope reduction is not limited to the outslopes of contour strip
mines.   It can be used to reduce the slope of any oversteepened spoil
pile. It  may be particularly effective for use on  steep spoil and tailings
slopes occurring at many western mines.

         Slope reduction must be accompanied by revegetatiori to be
effective  in pollution and erosion control.  Riprap or chemical (mainly
petroleum derivitives) stabilization can be substituted for revegetation
in arid climates where vegetation is difficult to establish and where land
use  considerations would allow.
         Slope reduction has proven to be an effective tool in stabilizing
                                  134 -

        -2nd  Cut Highwall
           -Temporary  Diversion  Ditch
               1st  Cut  Highwall
            1st Cut Spoil
         Original  Ground Surface
         7° Maximum  Storage Angle
                     1ST  STEP
 -Diversion Ditch
      2nd  Cut  Highwall
                          2nd  Cut  Spoil
             Original  Ground  Surface-

                     2ND STEP
   -Diversion Ditch
             -Final  Grading
             Original Ground Surface
                     3RD STEP

                 Figure  6.11-1
                         - 135 -            Reference No. 61

      2nd  Cut  Highwall
         -Temporary Diversion Ditch
               1st  Cut Highwall

                                    Ist   Cut Spoil
    Diversion  Ditch


              Final Grading
                                                     Angle of

Original  Ground  Surface
                      1ST   STEP
    Diversion  Ditch

       2nd  Cut  Highwall
                       2nd  Cut  Spoil
M i n e ra I  Sea m                   •"'>^i.- -.'

              Original  Ground Surface
                      2 ND  STEP
                                                  Toe of
             Original  Ground Surface-

                      3RD  STEP
                       Figure 6.11-2
                          - 136 -              Reference No. 61

steep spoil slopes and reducing erosion. It provides a stable base for

         Slope reduction results in a larger than usual disturbed area
and increased revegetation costs.  It is not as effective as contour re-
grading, but it is far less  expensive and is often the only practical
method of reclaiming abandoned contour strip mines in steep terrain.

         Slope reduction may not eliminate landsliding in extreme cases
of spoil instability and steep terrain.  Rapid erosion will occur on the
steep slopes unless vegetation is established concurrent with regrading.
Establishing trees alone is not sufficient to control erosion.   Planting
should include grasses and legumes.  Contour plowing and terraces
would also be helpful in controlling erosion and establishing vegetation.
         Costs are highly variable and are dependent on individual
mine conditions.  Cost will be less if slope reduction is accomplished
during mining rather than after the mine is abandoned.

         Costs can be expected to range from $500 to $4950 per hec-
tare ($200 to $2000 per acre).
         9, 61,  189
                               - 137 -

                    6.12 ALKALINE REGRADING
         This is a very specialized form of regrading that has limited
use.  This technique will be demonstrated by the EPA in the Elk Creek
Watershed, West Virginia.  This technique will be discussed for its
particular use in Elk Creek.  The same type of situation where this
technique would be applicable will undoubtedly  occur in other localities.

         This technique is not a true surface mine water control tech-
nique, but rather uses surface mine regrading to control underground
mine discharges.

         There has been extensive surface and underground mining on
the Redstone and Pittsburgh coals in the Elk Creek Watershed., The
Redstone coal is usually 10 to 15 meters (30 to 40 feet) above the Pitts-
burgh.  Most of the interval between seams is  composed of a low perme-
ability soft claystone with a thin lens (maximum thickness about 1 meter)
(3 feet) of limestone.  The underground discharges are normally acidic
because mine water does not have access to the limestone for neutral-
ization.  Surface mining breaks up the soft claystone and limestone, dis-
tributing limestone throughout the spoil, which makes it available for
neutralization.  The effect of the distribution of limestone was noticed
during a field view of the watershed.  Four-year old water quality data
showed a large acid discharge from an underground mine.  The outcrop
of the underground mine had been subsequently strip-mined and terrace
regraded.  The  underground mine discharge was passing through the
regraded soil material and was found to be alkaline.  Turbidity from
precipitating ferric hydroxide indicated that neturalization had recently
occurred.  Several other strip mine discharges were found to have
similar conditions.

         Regrading of strip mine spoil caused the underground mine
discharge to flow through spoil material resulting in neutralization from
the disseminated limestone.
                                - 138 -

         This technique  is scheduled for demonstration by the EPA at
several sites  in the Elk  Creek Watershed.  Before and after water
quality sampling will determine degree of effectiveness.  This tech-
nique would appear to be applicable for similar conditions in other
areas.  A hydrogeologic study would be required to determine  appli-

         Slurry trenching (the next technique description) is to be uti-
lized in conjunction with an alkaline regrading demonstration to achieve
wider distribution and longer retention time of acid water in the alkaline
         The costs for alkaline regrading are the same as for terrace
backfilling, which ranges between $500 and $4940 per hectare ($200
and $2000 per acre).
         9, 40
                                - 139 -

                       6.13  SLURRY TRENCHING
         Slurry trenching  is primarily a waste water control technique.
However, it is to be used with a regraded surface mine, and is to be
demonstrated with alkaline regrading techniques.

         A slurry trench is a narrow vertical trench excavated in un-
consolidated  materials.  The vertical trench walls are maintained by
filling the trench with a bentonite clay and water slurry,,  The excava-
tion may be accomplished  with a backhoe, clam shell, dragline or
connecting drill holes.  The slurry material is backfilled with the pre-
viously excavated material (if it is of the proper grain size distribution).
The resultant backfill mixed with bentonite forms a relatively imperme-
able ground water dam.

         The technique has not yet been used in mine  drainage; control.
Its  primary use has been for dewatering building foundations and for
ground water cut-off trenches below dams placed on unconsolidated  ma-
terials .

         The slurry trench will be demonstrated by the EPA in conjunc-
tion with alkaline regrading in the Elk Creek Watershed, West Virginia.
It will be placed in regraded spoil and keyed into the underclay to form
a ground water dam. The placement and top level of  the trench will be care-
fully controlled to cause acid underground mine water to rise in the alka-
line spoil. The flow path through the spoil and the retention time will
be increased, causing increased neutralization.  Rise in water level at
the discharge point will also cause the  water level to  rise in the under-
ground mine, reducing acid production.

         This technique should have further application.  It could  be used
to flood underground mines where the down dip outcrop has been stripped
away  and the rise within the mine is small.  The amount of  inundation
would be limited to the elevation of the top of the trench.  This would
                               - 140 -

be controlled by geometry of the strip mine spoil as related to the
attitude of the underground mine.

         Present indications are that the height of the trench should
be limited to 10 meters (33 feet).

         This technique may have application for raising ground water
levels in pollution-forming  materials, particularly valley fill tailings
         This technique will be evaluated in the Elk Creek Demon-
stration  project.  Its effectiveness as an impermeable barrier has
been well documented by numerous  construction projects (not related
to mine water pollution control).
         Costs of slurry trenching are expected to range from $16.00
to $43.OO per square meter ($1 .50 to $4.00 per square foot).
         40,  210
                                - 141


   7 . 0
 - 143 -


                     7.1  METHOD DISCUSSION
         Sedimentation is defined as the erosion, transport,and deposi-
tion of material by water and wind.   Erosion occurs naturally as  part
of the weathering cycle, and is greatly accelerated by mining  activities.
Physical disturbance of soil and  rock exposes  materials to erosion
mechanisms and increases  credibility.  Moving water is responsible
for most erosion from mined areas. However, wind erosion may be a
significant transport mechanism, particularly in arid regions. Wind
will transport fine-grained  materials over wide areas, and occasionally
directly to bodies  of water.  This widely scattered material will enter
the surface flow network during periods of surface runoff.

         The need for erosion control became  apparent long ago.   The
science of erosion  control has advanced significantly.  Extensive re-
search has been performed by the Departments of Agriculture and In-
terior of the Federal Government and by universities.  The EPA  publi-
cation "Guidelines  for Erosion and Sediment Control Planning and Im-
plementation" (EPA-R2-72-015)  contains an excellent discussion  of
erosion and erosion control techniques.

         This report is not  intended to be a complete treatise  on the sub-
ject of erosion control.  It is only intended to present specific erosion
control  techniques  that  have had  widespread use in the mining industry.

         Erosion control procedures used in the mining industry are not
as sophisticated nor as expensive as the techniques employed  in urban
and highway construction.  The large amounts of disturbed land and
limited  budgets of reclamation agencies generally preclude use of all
but the most elementary and low cost techniques.  Revegetation,  the
simplest and most  effective erosion control mechanism,  has  not even
received widespread use.  Unfortunately, erosion control for  most sur-
face mines in the past has been the planting of a few seedling  trees on
an improperly prepared and sometimes toxic surface.

         Erosion and sediment control and mine water chemical pollu-
tion control sometimes are in conflict.   Erosion control calls for de-
                                - 145 -

crease of water velocities.  However,  this factor can increase infiltra-
tion.   If the underlying material contains water-leachable pollutants,
infiltration should be discouraged.  Mine water pollution control calls
for rather rapid surface water runoff and  reduced infiltration.  Rapid
runoff should only be encouraged to the extent that erosion does not
occur. Where chemical pollution can occur, a good balance must be
achieved between sediment and chemical pollution control.  The princi-
pal pollutant from many mines is sediment.  In this case water pollu-
tion control is  entirely erosion and sediment control.

         Erosion control is accomplished  by several basic methods.
One of these is isolation of erodible  material from  moving water.  This
is accomplished by diversionary channelization, and covering proce-
dures .

         Reduction of velocity of water flowing over erodible material
is also effective.  This is  accomplished by various  means,  including
slope control,  revegetation and construction of flow impediments
(mulches, scarification, dikes, contour plowing, and dumped rock).

         Decreasing credibility of the material is another method.
This can be accomplished  by compaction,  chemical stabilizers, burial
of erosion prone materials,  and revegetation.

         If erosion prevention methods do not achieve desired effective-
ness,  suspended material  can be removed from the transport medium.
This is usually accomplished by construction of a collection and con-
veyance system leading to an impoundment.  The pond is constructed
to provide water with sufficient detention time under quiescent (or re-
duced  velocity) conditions  to settle out suspended materials.  Systems
whereby water is spread out over a flat or rough textured area have
proven effective in causing sediment deposition.  Wind fences are cap-
able of reducing wind velocities to at least partially cause wind-borne
sediment to be deposited.

         Preventive techniques are often insufficient to curtail erosion
from active surface mines.  Settling ponds are usually needed.  The
most efficient erosion control systems combine settling ponds with
preventive measures such as diversion and/or revegetation.
                                - 146 -

         The choice of erosion and sediment control techniques should
be made during mine preplanning, and should  consider local conditions,
including credibility of disturbed material, topography, rainfall, rela-
tionship of surface flow channels, drainage area tributary to the mine,
site hydraulics, and settleability of transported material.

         Erosion and sediment control should  be an essential part of
surface mining and reclamation  planning.  It is  not intended as a com-
plete abatement plan. It should  be used in conjunction with other abate-
ment techniques such as regrading, controlled mining, water infiltration
control, handling of pollution-forming materials, and waste water con-

         Legal considerations influence erosion control planning.  Local,
state,  and federal laws often regulate the infringement on stream chan-
nels, allowable water velocities, impoundment construction, and dis-
charge limits of settleable solids.  Increasing sediment amounts and
water velocities in downstream flow paths can cause downstream prob-
lems.  Failure of water impoundments can result  in loss  of life and
massive damages as evidenced in the pond failure in Buffalo Creek,
West Virginia in February 1972.

         Costs of erosion and sediment control are extremely variable
and will need to be developed for individual installations.   Local physio-
graphic, weather and soil conditions will  cause  extreme variations in
control costs.
                                - 147 -

                           7.2 DIVERSION
         Diversion is the process of collecting and channeling water
before it reaches erodible materials.  This is usually accomplished by
excavation of ditches along the high end of a mine or wherever signifi-
cant amounts of water will drain to the mine.   Water is collected before
it reaches a disturbed area and conveyed around or through the area to
a receiving stream.  Topographic maps are useful in locating diversion
and conveyance ditches. Size and gradients of the ditches are designed
to carry expected flows estimated by knowledge of historic storm inten-
sities and drainage areas. Storm intensity data can be obtained from
the National Weather Service, local weather services, State; Highway
Departments, and the Soil Conservation Service.  Flow computation
procedures can be obtained from these same agencies.  Flurnes, cul-
verts, riprap,  and various forms of matting can be used  in channels
conveying water down steep slopes to prevent erosion. Dikes can be
used in the same manner as ditches.  They are often used together when
material excavated from a ditch is used to form a downslope  dike.

         Diversion can be  employed within the mine to collect and con-
vey incoming ground water prior to contact with erodible material.
         In most cases, diversion is an economical form of erosion con-
trol.  It is not meant to function as a complete erosion control, but as
an integral part of an erosion control plan.  It is less expensive than
constructing settling ponds and repair of erosional damage.  Surface
flow can be effectively gathered and conveyed from the site before con-
tacting erodible material.
                               - 148 -

         Diversion ditches cost from $1 .30 to $3.90 per cubic meter
($1 .00 to $3.00 per cubic yard).  Dikes range from $0.45 to $0.85 per
cubic meter ($0.35 to $0.65 per cubic yard).  A 91 .5 centimeter (36
inch) /£ section of bitumized fibre pipe averages $32.80 per linear
meter ($10.00 per linear foot) in place.  A 45.7 centimeter (18 inch)
corrugated metal pipe is $26.00 per linear meter ($8.00 per linear
foot) in place. Concrete costs approximately $39 per cubic meter
($30 per  cubic yard) in place. Asphalt paving ranges from $2.40 to
$6.00 per square meter ($2.00 to $5.00 per square yard) In  place.
Dumped rock costs from $2.60 to $7.80 per cubic meter ($2.00 to
$6.00 per cubic yard) and riprap ranges from $13.00 to $34.00 per
cubic meter ($10.00 to $25.00 per cubic yard).  Jute matting costs
$0.70 to  $2.40 per square meter ($0.60 to $2.00 per square yard).
         22, 34, 61, 115, 119, 166,  179
                               - 149 -

                       7.3 RUNOFF CONTROL
         The section on Diversion was primarily concerned with tech-
niques directed toward preventing water from entering a mined area.
Runoff control  is the use of various techniques to handle water after it
reaches the mine site. Runoff control, as used  in this context, is
meant to imply control of erosion caused by water flowing over a mined
area.  Unfortunately,  runoff control and pollution control are sometimes
conflicting. Pollution  control of chemical contaminants from mine
spoils and wastes often involves reducing the amount of infiltrating
water.  Runoff control usually results in increased infiltration. The
basic causes and degree of pollution should be examined at each mine
to determine if use of  runoff control measures will result in increased
chemical pollution.  Water pollution in some mines is caused by sedi-
ment and not by chemical changes.  In these instances, runoff control
measures can be utilized without causing the adverse effects of chemi-
cal pollution.

         Runoff control can also reduce chemical pollution:   the mine
surface is stabilized,  preventing erosion from exposing new material
to oxidation.  Runoff control is  instrumental in helping to establish
vegetation, decrease erosion, and  increase infiltration to root sys-
tems. In this fashion, runoff control  helps to decrease chemical pollu-

         There are many runoff control techniques available for use on
surface mined lands.  Choice of technique will likely be a question of
economics. Some of  the techniques may be prohibitively expensive be-
cause of the large amount of disturbed area involved and limited fund
availability.  The many techniques of runoff control are not discussed
in detail in this report.  Erosion control is a science of itself and num-
erous agencies and institutions  are conducting research, demonstrating
techniques, and producing literature on the subject.
                               - 150 -

         Establishment of vegetation is probably the most effective,
cheapest, most universally applicable of all the runoff control techni-
ques.  Revegetation of surface mined lands is discussed in Section 8
of this report.

         Mulching can be used for runoff control.  However, it is often
a temporary measure. It is commonly used to facilitate germination
and early growth of vegetation. The mulch decreases erosion of a seed-
ed area, tends to hold water near the surface of a mine and, in the case
of organic mulches, adds nutrients to the soil. Mulches are also used
to temporarily reduce erosion in areas where other erosion control mea-
sures will be utilized at a later date.  The function of a mulch is to pro-
tect the surface from the impact of raindrops and reduce the velocity
of water on the land surface.  The most common mulch is straw,  which
is used quite extensively for revegetation.  Straw is the cheapest and
most readily available mulch. Wood fiber mulches made from shredded
trees are being used more extensively as a replacement for straw.  Both
of these mulches can be applied by hand spreading, by large shredders
and blowers,  or hydraulically.  In areas with high winds and low mois-
ture, the mulch can be held in place with hemp or wire nets.  This is
quite expensive and will have only limited use. Artificially produced
mulches are also available, as described in reference 115. Mulches
must be selected to fit the climatic conditions where they will be used.

         Slope reduction is effective in helping to achieve runoff control.
Steep slope areas are graded to gentler angles to reduce water velocity.

         Riprap has been used in western areas to reduce erosion where
vegetation cannot be established.  Riprap is expensive and would only be
practical for extreme slopes, and arid areas, where revegetation is very

         Terracing of embankments such as described in the Head-of-
Hollow Fill  section of this report  is effective.  This is especially appli-
cable in areas containing tailings piles where steep and unstable slopes
cannot be avoided.  A series of terraces can  be cut in an embankment to
intermittently reduce water velocities on steep slopes.  A series of par-
allel diversion ditches excavated in a configuration nearly parallel to
surface contours is an adaptation  of this technique.  The diversion ditches
collect moving water at regular intervals along a slope,  and the water
is subsequently conveyed out of the disturbed area and discharged where
erosion cannot occur.
                                - 151 -

         Surface scarification is an effective runoff control technique.
It is accomplished by creating a series of closely spaced ridges roughly
parallel to the contour lines.  The  ridges reduce water velocity and
cause part of the sediment load to settle out in the adjacent lows.  Scar-
ification is performed by contour plowing, furrow grading, contour disc-
ing, or any other means of abrading the surface parallel to contour.  This
can be performed in the most rudimentary fashion by having machinery
travel  the area parallel to contour.  The wheel or tract scars then act
as the  ridges and valleys.  Scarification is temporary, and should be
used in conjunction with revegetation.  The beneficial effects of scarifi-
cation  are short lived,  because the ridges tend to erode and the valleys
fill with sediment.  Scarification serves to help establish vegetation and
control erosion until the vegetation is established. Scarification further
serves to concentrate water in the low spots. This is helpful for establish-
ing vegetation in arid areas.

         Runoff control can be achieved by the use of surface stabilizers.
There  are many of these products marketed. They are usually applied
by spraying a liquid over the surface.  This stabilizer reduces erodibility
of the surface.  They are often expensive and temporary,  and are sub-
ject to weathering and physical damage.
         Costs for the various items necessary for vegetation are out-
lined in more detail in Section 8.0, Revegetation. Mulching (hay)
approximate average cost is $100 per hectare ($ 40 per acre).

         Contour plowing should range from $0.80 to $1 ,60 per meter
($0.75 to $1 .50 per yard), depending on terrain.  Costs for slope re-
duction and terracing of embankments are highly variable and depen-
dent on individual mine conditions.  Costs can be expected to range
from $500  to $4940 per hectare ($200 to $2000 per acre).

         Chemical stabilization varies from $120 to $1,000 per hectare
($50 to $400 per acre).  Diversion ditches and riprap costs are given
                               - 152 -

in Section 7.2, Diversion.
         34, 37, 42, 47, 53, 56, 92, 108, 115, 119, 134,  171
                              - 153 -

                    7.4 CHANNEL PROTECTION
         Various techniques can be used to control erosion in channels.
Most of these involve placement of a protective liner such as riprap,
concrete, jute matting, or dumped rock in the channel to reduce water
velocities and/or protect the underlying material.  Cross channel dikes
or energy dissipators are also used for channel protection by reducing
water velocities.  Flumes are often used to prevent erosion of channels.

         Dumped rock, riprap and jute matting are the cheapest and
most widely used channel protectors.

         These techniques are used for channels through a mined area
and to protect the waste piles from nearby streams.  Riprap and dikes
have  been employed to protect mine tailings piles from adjacent streams,
        All of the above-mentioned techniques have been proven effec-
tive.  Choice of technique is governed by water velocity and installation
cost.   It must be recognized that indiscriminate use of erosion control
techniques for channels can be harmful to existing aquatic biota.  This
factor should be given careful consideration during design.
         Costs for energy dissipators are quite variable and depend on
                               - 154 -

type and size of dissipator desired.  Other channel protection costs
are defined in Section 7.2, Diversion.
         34, 53,  56,  115,  119, 162
                              - 155 -

                           7.5  SETTLING
         Settling is used to trap sediments being transported in runoff.
Techniques described in other sections of this report discuss erosion
prevention.  It is extremely difficult to control erosion from active sur-
face mines because of the large amount of disturbed earth involved and
the continuing mining activity.  Erosion and sediment control measures
such as diversion and revegetation should be employed to reduce erosion
and sediment transport. Solids settling systems should  be incorporated
to remove sediments from most surface mining operations. Water
collection and conveyance systems are usually installed to carry water
to settling ponds.  Settling  occurs because of the decrease in water
velocity.  This lowers the competency of water to carry  suspended ma-
terial.  Size of a settling pond must be determined  from the amount of
flow anticipated and the time required for the suspended  material to
settle.  Proper residence time must be provided to ensure effectiveness.

         Snow fences have also been used to settle windblown  material.
Snow fences  were used on old uranium piles, but success was question-

         Settling can also be achieved without use of impoundments.
Distribution systems will reduce water velocity and depth,  allowing sus-
pended material to settle.   A  distributary is formed by distributing a
discharge over a large area.  The area should have a gentle slope and a
rough textured surface.  Effectiveness of a distributary system was
documented in "Effects of Placer  Mining on Water in Alaska."   (Ref.
No.  174).
                                - 156 -


         Properly designed settling systems are often adequate to re-
duce settleable solids to acceptable levels.  Flocculation systems are
required where settling alone will not achieve proper results.  Use of
settling ponds and flocculation is described in "Preventing the Sedi-
mentation of Streams in a Pacific Northwest Coal Surface Mine" (Ref.
No. 109.)

         Effectiveness of settling systems is based on settling velocities
of the material in suspension. A settling system must be designed so
there is sufficient residence time to allow a desired  amount of solids to
settle.  Residence time is controlled by amount of flow and capacity of
the impoundment.

         High flow conditions should be considered in impoundment de-
        Costs of settling ponds vary with type, size, and location.
Snow fence costs average approximately $3.30 per linear meter ($1 .00
per linear foot).

         2, 7, 9, 16, 17, 28, 32, 34, 38,  115,  116,  119,  138,  151,  174
                               - 157 -


       8 . 0
     - 159 -


                     8.1  METHOD DISCUSSION
         The revegetation techniques described in this section are used
to encourage establishment of a vegetative cover on disturbed lands.
Surface-mined lands are often hostile to vegetation.  Voluntary revege-
tation does not generally occur to a satisfactory degree for many
years, if at all.

         Revegetation is  one of the most effective pollution control
methods for surface mined lands.  If properly established  it will pro-
vide effective erosion control, and contribute significantly to chemical
pollution control.  Revegetation results in aesthetic improvement, and
often returns land to agricultural,  recreational, or silvicultural use-
fulness .

         A dense ground  cover stabilizes the surface with its root sys-
tem and reduces velocity of surface  runoff. A dense ground cover de-
posits yearly crops of organic matter on the surface and  can virtually
eliminate erosion.  A soil profile begins to form, followed by a com-
plete soil ecosystem. This soil profile acts as an oxygen barrier in
that the oxygen is utilized by soil bacteria.  The amount of oxgyen
reaching underlying pollution-forming materials is reduced.   This in
turn reduces oxidation, which  is responsible for most of  the pollution.

         A soil profile tends to act as a sponge that retains water near
the surface. The mine spoil materials are often permeable  and allow
water to infiltrate quickly. Little water remains near the surface.
Water held  near the surface by a soil profile is important.  It acts as
a surface coolant because it will evaporate from the surface. This de-
creases surface temperatures and enhances vegetative growth.  Water
evaporated from the surface is water that will not pass through under-
lying  potential pollution-forming materials.

         Vegetation also  utilizes large quantities of water in its life
processes and transpires it back to the atmosphere,  again reducing the
amount of water reaching underlying materials.  However, vegetation
does not necessarily reduce the amount of water reaching underlying
                                 - 161 -

materials, since certain types of vegetation increase infiltration.

         Difficulties encountered in reestablishing  vegetation on sur-
face-mined land result from disturbance of the area and inability to re-
store the area to its pre-mining condition.  Loss of the soil zone is a
major hindrance to revegetation and, therefore, topsoil stockpiling is
encouraged.  The natural hydrology of the area is grossly disturbed, and
this accounts for most of the revegetation problems in arid and semi-
arid regions.  Mining often results in steep, unstable slopes, which are
extremely hard  to vegetate. The surface condition of a mine  is often a
limiting factor for vegetation.   The surface is often toxic with high con-
centrations of salts,  metals and acid.  Chemical conditions may inhibit
or completely prohibit growth.  The surface is often rough-textured and
has little soil  or fine material to act as a medium for root development.
Many of the stony mine surfaces are often highly permeable,  and retain
little water near the surface (which is needed for plant growth).  Dark-
colored materials on the surface absorb large amounts of solar energy,
resulting in elevated  surface temperatures that discourage growth.  Nu-
trient levels are usually low and sometimes are insufficient to support
plant life.

         Too often, a number of these adverse conditions will occur at
one site.  Revegetation techniques are designed to reduce the effects of
these conditions or develop species tolerant to these conditions.

         Revegetation can be an entire pollution control plan in some
instances, but generally it must be an integral part of more comprehen-
sive plans that incorporate  regrading, diversion and overburden segre-
gation .

         Past revegetation efforts were primarily concerned with planting
trees. This is now believed to be inadequate, and any tree planting should
be accompanied by establishment of dense ground covers  of grasses and
legumes. Trees are not effective in erosion control for many years after
planting.  They  are slow to form soil profiles and do not provide effective
chemical pollution control until long after planting.  Wildlife grazing
(over-grazing) on revegetated  lands can also be a problem.
                                - 162 -

        The following sections present the various techniques that can
be used in revegetation.
                                - 163 -

                     8.2  TOPSOIL REPLACEMENT
        The best medium for plant growth at almost all surface mine
sites  is the topsoil that originally covered the area. Past mining
practices have largely ignored the presence of the soil, and mining
started without regard to stockpiling and saving the soil.  The soil
was subsequently mixed with the spoil or placed in the bottom of spoil
piles  where it was not available during regradtng.  Revegetation is usu-
ally successful when the original topsoil  is spread over the surface of
the mine after regrading the spoil.
         Topsoil stockpiling historically was not performed because of
the additional cost of scraping it from the site, stockpiling it, and pro-
tecting it from erosion. Multiple handling can be reduced by pre-mine
planning of spoil placement location and sequence of final grading

         Soil stockpiling is relatively simple when the reclamation plan
calls for contour regrading.  The soil is merely scraped downhill to
the low wall and covered with the spoil piles.  The spoil is regraded
upward during reclamation and the last  material encountered in the
bottom of the  pile  is the soil, which can then be spread over the surface,

         The soil can also be scraped upward initially, and deposited as
a dike on the highwall.  This will serve as a diversion ditch.  Any soil
left exposed should be temporarily revegetated to protect it from ero-
sion during the life of the active  mine.

         The soil should be considered as a valuable natural resource
                               - 164 -

and should not be wasted during mining.

        Topsoil can also be imported to the mine site for revegetation,
This is expensive and  is not practical in most instances.  The topsoil
borrow area could also be an environmental scar.
         Costs of soil stockpiling could only be developed through a
comparative analysis of mining, using this technique versus mining
without stockpiling soil.

         Costs of soil stockpiling could be developed from standard
cost manuals.  However, this would not reflect the true cost to the
miner, because he would have to remove the soil during  mining.  The
true cost, therefore, would be the difference between the optional
methods  of handling  the soil.  The cost would also vary according to
distance  moved, thickness of layer to be stockpiled, and terrain.
         211,  212
                                - 165 -

                   8.3  SURFACE PREPARATION
         The regraded surface of most spoils is not adequate to support
a good vegetative cover.  This section describes techniques that can be
utilized to enhance a regraded surface for vegetative growth.

         The surface texture is important, especially when grasses and
legumes are to be planted.  The mine surface should be raked, if prac-
ticable, to remove as much rock as possible and to decrease the average
grain size of the remaining material.

         Materials toxic to plant life should be buried during regrading,
and should not appear on or near the final surface.

         Dark-colored shaly materials should also be buried and not
appear on the final surface.  Dark-colored materials have also been suc-
cessfully mixed with light materals and supported vegetation.  These
materials are responsible for high surface temperatures caused by solar

         Compacted surfaces are not conducive to plant growth; they
should be scarified by discing, plowing or roto-tilling prior to seeding.
         The adverse effects of non-prepared surfaces are well docu-
mented throughout agricultural literature.  Unfortunately, sound agri-
cultural practices were too often ignored during surface mine revege-
tation accomplished in the past.
                               - 166 -

        Costs are not meaningful except on an individual application
basis. Costs will be entirely dependent upon the conditions of the mine
         56, 80, 145, 146, 149, 151, 170
                               - 167 -

                      8.4  SOIL SUPPLEMENTS
         Soil supplements are often required for establishment of a
good vegetative cover on surface-mined lands and refuses piles. These
surfaces are generally deficient in nutrients and should be supplemented
with applications of fertilizer.  Mine spoils are often acidic, and occa-
sionally basic.  Lime or acid must be added to adjust the pH into the
tolerance range for the species to be planted.   Fertilization is usually
required in semiarid and arid climates.  It may be necessary to apply
additional limestone to revegetated areas for some time to  offset con-
tinued acid generation and coating of previously applied calcareous ma-

         The amount  and type of fertilizers and pH  adjusters needed can
be determined  by soil analysis of the regraded  surface.  Soil tests
should be accompanied by pot and field trials.

         Other soil supplements are undergoing research and experi-
mentation.  Fly ash is a waste product of coal-fired boilers and resem-
bles soil in certain physical and chemical properties.  It is often alka-
line,  contains some plant nutrients, and possesses moisture retaining
and soil conditioning  capabilities.  Its main function is that of  an alka-
linity source and a soil conditioner.  Fly ash disposal hcis always been
a problem.  Use of fly ash on mine surfaces is promising because most
fly ash is generated in or near the coal fields.   The varying quality,
particularly with respect to pH, is a problem.   Fly ash is not  a com-
plete revegetation soil supplement by itself.  Fertilizer  and lime are
also required.  Doubts have been expressed relative to the  pollution po-
tentials of fly ash.  It may contain leachable pollutants.  Future re-
search, demonstration and monitoring  of fly ash supplements will prob-
ably develop  its potential use.

         Use of large quantities of limestone screenings applied to a
regraded surface mine is to be demonstrated as a source of long term
                                - 168 -

alkalinity for acidic spoils.  Acidic spoils generally continue to pro-
duce acidity as oxidation continues.  Use of lime for direct planting upon
these spoils is effective, but may provide only short term alkalinity.
The lime is usually used up  after several years and the spoil may re-
turn to its acidic condition.  Limestone screenings are of larger par-
ticle size and should continue to produce alkalinity on a decreasing
basis for many years, after which a vegetative cover should be well
established. Use of large quantities of limestone should also add
alkalinity to the receiving streams as well as neutralizing the spoil.
Limestone screenings are much cheaper than lime, providing larger
quantities of alkalinity for the same cost.  Application rates varying
between  99 and 494 tonnes per hectare (40 and 200 tons per acre) are
to be demonstrated in the near future in Pennsylvania and Maryland.

         Use of digested sewage sludge has good possibilities as a
soil supplement to replace fertilizer and to alleviate the problem of
disposal of the sludge.   Digested sewage sludge application requires in-
corporation of liquid or  dry  sewage sludges  into mine spoils or refuse.
Liquid sludge applications require large holding ponds or tank trucks,
from which the sludge is pumped and sprayed over the ground, allowed
to dry and disced  into the underlying material.  Dry sludge requires
use of various dry-spreading machinery before the material is disced.
Besides  supplying various nutrients, sewage sludge can reduce acidity
and/or alkalinity, and effectively increase soil absorption and moisture
retention capability.

         Rates of  application would be a function of vegetation species
and climate.

          Use of any soil supplement Is governed by a number of variables
 Before using a supplement an analysis of its characteristics and the spoil
 characteristics must be made.

          Standard commercial fertilizers are available almost every-
 whe re.
                                - 169

         Limestone, digested sewage sludge, and fly ash are all limited
by their availability and chemical composition.  Unlike commercial fer-
tilizers, the chemical composition of these materials may vary greatly,
depending on how and where they are produced.  Therefore, a nearby
supply of these supplements may be useless if it does not contain the
nutrients or pH adjusters that are deficient in the area of intended ap-
plication.  Fly ash,  digested sewage sludge, and limestone screenings
are all waste products of other  processes.  They are usually inexpen-
sive and may even be free in some cases. The major expense  related
to any of these wastes, is the cost of transporting and applying the ma-
terial to the mine area.  Application of liquid digested sewage sludge
can be quite costly,  due to the need for special spray and holding de-
vices .

         Uniform application is  required to effect complete and even
revegetation.  Also, incorporation of other procedures such as re-
grading, erosion control, soil stabilization, planting techniques, and
proper species selection must be considered for each situation to in-
sure a successful vegetative cover.

         When large amounts  of certain  chemical nutrients are utilized,
it may be necessary to institute nutrient controls to  prevent chemical
pollution of adjacent waterways. Nutrient controls may consist of proper
selection of vegetation to absorb certain chemicals,  or the construction
of berms and retention basins where runoff can be collected and sampled,
then either  discharged or pumped back to the spoil.

        One or more supplements can be utilized to  create
a soil condition conducive to vegetation on most mine spoil or refuse.
However, an analysis  of some spoils may indicate the  need for such
extensive supplementation and related controls that it would be econo-
mically unfeasible.  In this case,  topsoil application to support vege-
tation may be a viable alternative.

         Use of soil supplements should be determined by the require-
ments of the species to be planted,  analysis of present soil conditions,
requirements to adjust present soil conditions to desirable levels for
the species, and analysis of the particular supplement.
                                - 170 -

         Costs are affected by requirements of the species to be
planted and the nature of the soil.  Costs can be  reduced by selecting
species that require less adjustment of present soil conditions.  If
the spoil is acidic It Is best to use  a species that Is acid-tolerant.

         The average cost for fertilizer application is $120 per hectare
($50 per acre).

         The general range for limestone screenings is $1 .10 to
$4.50 per tonne ($1 .00 to $4.00 per ton) depending on transportation

         Lime application  averages $150 per hectare ($60 per acre)
depending on spoil acidities.

         Cost data Is not available  for digested sewage sludge; but,
because it  is a waste product,  it is reasonable to assume the acquisi-
tion costs will be nominal  or zero.  Costs will vary according to
haulage distance and handling characteristics of  a particular sludge.

         Fly ash is generally available free from the site or at a nom-
inal cost of $0.30 to $1 .70 per tonne ($0.25 to $1 .50 per ton).  Appli-
cation costs are again dependent upon haulage distance.

         Haulage rates can be estimated using a  figure of $0.07
per tonne  per kilometer ($0.10 per ton per mile).  Costs should In-
clude acquisition, haulage, spreading, and mixing  (discing) if required.
         1, 3, 27, 36, 62, 124, 145, 147, 149, 154
                              - 171 -

                     8.5  SPECIES SELECTION
         Careful consideration should be given to selection of the species
to be planted on surface-mined lands.  Species should be selected on the
basis of a land use plan which is based upon the degree of pollution  con-
trol to be achieved,  and the site environment.  As  previously described,
a dense ground cover of grasses and legumes is  preferable to tree seed-
lings from a pollution control standpoint.  There are ma.ny species  and
varieties of grasses and legumes to choose from.  Trees and shrubs
can be planted along with the grass cover.  Trees are often needed  in
areas of poor slope stability to help control landsliding.

         The intended future use of the land is an important considera-
tion with respect to species selection.  It may be preferable to return
surface-mined lands to high use categories, such as agriculture, if the
land has the potential for growing these crops.   In  many cases,  the
spoil potential is so  low that the choice is  limited to finding any species
that will grow.

         Many strip  mines are in rural and mountainous areas.  Terrain,
climate and soil conditions often limit future agricultural usages.  These
lands can be planted as game food areas by addition of game food species.
Desirable and adaptable tree species can be planted for later harvesting
of wood products.  Surface-mined lands may have potential as pasture
area if the land management conditions are feasible.

         Environmental conditions,  particularly  climate, are important
considerations in selecting species.  It is  best to choose species that
are native to the area, and particularly species that have been success-
fully established on nearby mines with similar climate and spoil con-
ditions.  Importation of alien species should be carefully considered,
based on their demonstrated ability to withstand  climates similar to
the mined areas.
                                - 172 -

         Choice of vegetation should be based on all of the preceding
considerations.  It may be best to first consider the species for which
the least surface preparation and supplementation will be required.  A
list of desirable species can be made and cost and effectiveness values
can be determined.  Land values before and after vegetation should be
considered in the selection.  In most Instances, except where specific
agricultural crops are desired,  It would be best to plant several com-
patible species to insure success in case  of failure of any one species.
A plot of land left unattended will succumb to plant succession where
species dominance and typical associations of species will change as
the vegetation evolves through each successive stage.

         Introduced plant species may have to be metal-tolerant.  Intro-
duced plants may have to be maintained for several years by fertiliza-
tion and  irrigation until  native vegetation invades and reestablish
         Success of the vegetation will depend on the ability of the
 species to provide a dense ground cover.  The best matching of species
 to the site conditions and climate is usually preferable.  Major use of
 soil supplements to suit a particularly desirable species Is not recom-
 mended unless a maintenance program Is established to maintain these
 conditions.  For instance, to attempt to grow a species that is intoler-
 ant of acidic conditions on  acid spoils  would  require regular applications
 of neutralizers.

         It is beyond the scope of this  report to present the various
 species,  their range of adaptability, their pollution control attributes,
 and their soil requirements.  Some of this work has already been per-
 formed and can be found in the vast storehouse of agricultural litera-
 ture.  Consultation with an agronomist would be helpful in species
                                - 173 -


         Costs are highly variable and depend on the individual cost of
the following items:

         1)  necessary surface preparation
         2)  soil supplements
         3)  seed or seedlings acquisition
         4)  planting
         5)  maintenance; such as additional soil supplements
            or irrigation

         Costs should be justified from pollution control considerations
and future land use potential.
         56, 213, 214, 215
                               - 174 -

                    8.6  PLANTING TECHNIQUES
         Seeds and/or transplants are the two methods used to initiate
a vegetative cover.  Transplants are seeds which have already germin-
ated and are mature enough to be  moved from one area and planted in
another.  In either case proper distribution is necessary to effect
a good growth, and can be accomplished by a number of available plant-
ing techniques.  Seeding can generally be performed by either broad-
casting or drilling.

         Broadcasting is scattering  seed  directly on the surface without
subsequent soil coverage.  Both manual and mechanical means can be
employed to distribute seed.  However, manual applications are rare
and only feasible for small areas.  Mechanical application can be pei—
formed by dropping the seed from aircraft, blowing it over an area by
a fan-created airstream, metering it from ground roving spreaders,
and by mixing it with a liquid for hydraulic dispersal.

         Drilling is classified as any process which deposits seed into
an artifically-formed surface depression  and subsequently covers the
seed with soil material. A variety of machines are available to perform
this operation, however, they are all generally alike.  Each machine
provides a cutting or compaction device to create a depression.  Immed-
iately following this is a device which drops the seed.  Finally an attached
rake or drag pulls soil  material into the depression.

         Planting seedlings requires that their root systems be buried.
Machines such as augers and seed drills  may be used to create holes,
and some machine adaptations will even place and cover the plant.  How-
ever, usually seedlings are placed and covered manually.  Under cer-
tain conditions special planting procedures may have to be used. Ex-
periments with tubelings and supplemental root transplants to  establish
dryland vegetation are being  conducted by the Montana Agriculture Ex-
periment Station.
                               - 175 -

         Tubelings are plant seedlings nursery-developed in two-ply
paper cores 0.6 meters (two feet) in length, 6.35 centimeters (2%. inches)
in diameter, and reinforced with a 1.25 centimeter (/^ inch) square mesh
plastic sleeve.  When the root system develops and extends from the
tube, the tubeling is placed in  an augered hole in the field, sealed around
the top,  and abandoned.

         Supplemental root transplanting requires removal of a pair of
interconnected seedlings.  The top of one seedling is  pruned off, leaving
two root systems connected to the unpruned seedling.  The horizontally-
connected root systems are then planted in a vertical attitudes with one
down in deep soil moisture and the other in the upper, drier, surface soil,
         Broadcast seeding is the least expensive procedure for estab-
lishing a vegetative cover,  and is particularly useful for large areas.
Use of either broadcasting or drilling for seed application will depend on
type of terrain, seed species and weather conditions.

         Dry broadcasting is not effective in high winds or during intense
rainfalls.  These conditions curtail effective dissemination of seed par-
ticles and erode seeds lying on the surface, creating an uneven distribu-
tion.  A hard or compacted surface material will amplify the erosion pro-
blem.  This technique effects a wide dispersion.  Therefore, it cannot
be used to apply species in rows or other selective patterns.  This is an
excellent seeding technique under favorable conditions.  Broadcasting
effects a rapid and relatively inexpensive seed distribution especially
applicable to large areas.

         Drilling requires use of land roving machines and is greatly
restricted by steep slopes and rough terrain.  This technique is slower,
more expensive and does not provide the extensive coverage that is ob-
tained from broadcasting.  Essentially this technique is best suited for
relatively even terrain over a small surface area.  The confined seed
distribution renders it especially useful for planting agricultural seeds.
                               - 176 -

         Transplanting is best for initiating a rapid vegetation.  Both
seedlings and seed provide established root systems to stabilize the soil
and create a surface cover which dissipates the energy of wind and rain.
This is the most expensive planting technique due to plant costs and be-
cause manual labor is often necessary for planting.  The expense of
transplanting makes it more feasible for small areas or for surfaces
which will not promote seed  germination.

         Hydraulic or  hydroseeding accompanied by hydro-mulching is
receiving widespread use. This method will help keep the seeds in
place, reducing the effects of wind and water erosion.  This technique
can be used in almost  any terrain as  long as all points are accessible
within range of the sprayer.   Hydroseeding is advantageous in that it
can plant large areas quickly, combining fertilizer,  lime, seed, mulch
and moisture in one application.

         Choice of planting technique will be dependent on species selec-
tion.  Some  seeds must be buried to  germinate.   Some plants will not
germinate and will have to be planted as seedlings.  Grasses and legumes
are generally acceptable for hydroseeding.
         Broadcast seeding generally averages $500 to $1200 per hec-
tare ($200 to $500 per acre),  including materials,  equipment and labor.
Planting tree seedlings costs  about $0.06 per tree, depending
on size and type .

         Hydroseeding varies from $500 to $2000 per hectare ($200 to
$800 per acre),  including materials, equipment, and labor.
         56, 80
                               - 177 -

                           8.7 ARID AREAS
         Revegetation of arid and semiarid  areas deserves special con-
sideration because of the extreme difficulty in establishing vegetation.
Lack of rainfall, coupled with effects of surface disturbance creates a
condition hostile to growth.  Experimentation and demonstration pro-
jects are presently being conducted to solve the problem.  Three general
techniques have been explored: moisture retention;  irrigation; and use
of tubelings.

         These techniques are being developed for use on abandoned
mined lands.  It is expected that revegetation would  be easier on newly
mined lands if better mining and planned reclamation techniques were
employed during mining.   Regrading and overburden segregation should
prove helpful.

         Moisture retention utilizes entrapment,  concentration and pre-
servation of water within  a soil structure to support vegetation.  This
may be obtained by utilizing pits, snow fences,  mulches,  deep chiseling,
gouging, offset listering,  dozer basins, and condensation traps.

         Pits are depressions created to collect and maintain storm
water runoff.  They are designed to collect and concentrate water, pro-
viding pockets of moisture for plant growth.

         Snow fences can be utilized to collect wind-blown snow in or
adjacent to revegetation areas.  When the drifted snow melts,  moisture
is released to infiltrate the soil.  Snow fences  reduce the sublimation
losses of the snowfall.

         Mulching is application of various soil covers, such as wood
chips, straw, hay or other suitable material, to promote collection and
retention of moisture.  A mulch blanket creates a resistance to sur-
face water runoff which facilitates infiltration and, because it is a cover,
                                  178 -

moisture loss through evaporation is reduced.  Mulching also creates
a resistance to wind and water erosion.

        Deep chiseling is cutting of parallel slots, 15 to 20 centimeters
(6 to 7 inches) deep, in compacted soils.  Generally, large agricultural
chisels, or other cutting instruments,  are towed behind a suitable vehicle
in a direction perpendicular to that of surface runoff.  The resultant
slots and loose soil impede runoff and  increase infiltration.

        Terracing is  the channeling or embanking of constructions
across the sloping lands on or approximately on contour lines at specif-
ic intervals.

        Gouging is the creation of many small surface depressions
approximately 25 centimeters (10 inches) deep,  46 centimeters (18
inches) wide and 64 centimeters (25 inches) long,  usually with  a back-
hoe to enhance collection, retention, and concentration of runoff.

        Offset listering is excavation  of a series of shallow trenches.
This technique is generally accomplished with a bulldozer or other
suitable earth mover,  and functions similarly to gouging and deep chisel-

        Dozer basins are large depressions in the soil designed to  ac-
complish the same effect as the above  three techniques. The basins
are normally created by the tilted blade of a bulldozer about 0.9 meter
(3 feet) deep, 7.6 meter  (25 feet) long and at intervals of 9 meters
(30  feet).

        Condensation traps are plastic coverings designed to collect
and distribute moisture to plant seedlings.  A deep planting basin is
excavated and a stock  seedling implanted in the center.  The basin is
covered with a plastic sheet which is heeled in around the basin's outer
edges to contain air.   After cutting  an  opening through which the seed-
ling may protrude, the sheet is weighted in the center with rocks, creat-
ing  a taut funnel configuration.  Thus,  condensate collecting on the
underside of the plastic can trickle down to the seedling root system.

        Irrigation is artifical addition of water to areas with inadequate
                                - 179 -

natural water supplies for the purpose of establishing vegetation.

         Pipes and/or ditches are used to transfer water from a supply
such as a pond, stream, river, well, lake, or holding tank to dry areas.
Movement from the supply to the dry area can be created by gravitational
flow and/or pumping, depending on their differences in elevation.  In any
case, the final total area distribution is executed by networks of ditches
or spray pipes.

         The primary prerequisite for any irrigation system is a suffi-
cient supply of water of acceptable quality and an effective distribution
network.  Ideally,  the supply will be close to and at a higher elevation
than the distribution area.  These conditions will promote use of short-
er and less expensive ditch or pipe transfer systems, and provide a
gravitational flow. This eliminates pumps, which require continouous
power and maintenance.  However,  no matter how favorable the supply,
other factors  must be considered.  Ditches in permeable materials will
require an impervious lining to prevent water loss.  The amount of
water introduced onto the vegetation will have to be constantly controlled
to satisfy the  vegetative requirements. Irrigation of mine wastes which
contain water-reactive pollutants must cease immediately  after the vege-
tation is established to preclude continuous pollutant leaching.

         Obtaining water rights may be especially difficult in the arid
and  semiarid  regions of the country where this technique is used.
         Use of moisture retention techniques is experimental, and fur-
ther development will be necessary.  Evaluations of the various techni-
ques are contained in the articles referenced at the end of this section.

         Water availability is generally low in areas that could use ir-
rigation.  Irrigation could cause pollution problems if used on materials
that contain water-leachable pollutants.  Irrigation would, seemingly,
only be practical where it could be used  intermittantly  during peak plant
                                - 180 -

demand and low rainfall periods for the initial establishment of vegeta-
tion.  If it could be used for initial establishment, then be discontinued
after vegetation has taken root, it may be feasible.  Continuous irriga-
tion would be practical only if a marketable crop could be produced to
offset the cost.

         Techniques of large scale revegetation of disturbed lands in
arid and semiarid regions have not been documented.
         Costs are not presented because of the developmental nature
and variability of local conditions for these techniques.
         39, 80,  108,  115, 122, 134, 150
                                - 181 -

                         8.8 ALPINE AREAS
         Revegetation of alpine areas is given special consideration be-
cause of the difficulties involved, and lack of knowledge for making these
sensitive ecosystems suitable for revegetation.  A study of mine re-
clamation in alpine terrains is to be accomplished by EPA Region VIII,
headquarters in Denver, Colorado.

         Knowledge of alpine revegetation may be gained during con-
struction of the Trans-Alaska Oil Pipeline.
         There are no demonstrated techniques for revegetating
alpine mine areas.  Any future mining in these areas will probably re-
main unvegetated for long periods of time.
                               - 182 -

     - 183 -


      9 . 0
     - 185 -


                     9.1  METHOD DISCUSSION
         Many water pollution problems can be avoided by use of water
control preplanning for future mining operations.  Water producing zones
such as faults, fracture zones and aquifers should be identified by photo-
interpretation, field geology, and core borings.  Special provisions can
be included in the initial mining plan to avoid these zones.  A mine open-
ing can be sited so that there is a good area for deposit of tailings piles,
and for location of treatment facilities.  Progression of mining can be
planned to allow for backfilling of waste materials.  Mine openings can
be situated so that there will either be complete inundation or zero dis-
charge on completion of mining.  Planned flooding of the mine will indi-
cate the location of the points of highest hydrostatic pressure that will
occur.  Mineral barriers of sufficient size to withstand this head  of
water can be allowed to remain in place to permit flooding.
         The techniques described in this section are all control methods
that can be incorporated with active underground mines.  Most of the
techniques are aimed at preventing water pollution after mining is com-
pleted. The water pollution generated during mining can be treated to
present effluent standards, but under existing requirements, treatment
is unlikely to occur after completion of mining.  All of these techniques
increase the cost of mining.

         Daylighting of underground mines is also presented in this
section.  It is not a controlled mining method, but it is a means of con-
trolling water pollution from underground mines, and as such is in-
cluded in this section.
                                - 187 -

                    9.2 PREPLANNED FLOODING
         Most pollution forming materials require oxidation for increased
solubility. The sulfides which are responsible for most pollution are
relatively insoluble and inert until oxidized.  Underground mining pro-
vides a source of oxygen to these minerals, which have only limited oxygen
contact prior to mining.  If a mine contains air after abandonment, then
the minerals will continue to oxidize.  Flooding of a mined zone is the
only practical method of eliminating  the oxygen source under present tech-
nology.  Elimination  of free air atmosphere greatly  reduces oxidation.
Ground water entering a mine will have a small amount of dissolved
oxygen: on the order  of 0 to  10 mg/l. This supply is insufficient to sus-
tain any significant amount of pollution formation.  Flooding is not al-
ways the best solution, because some minerals will  be dissolved under
acidic conditions,  which are likely to occur during flooding.

         Free air  oxygen is  not always required for  oxidation.  For ex-
ample, pyrite can be oxidized by ferric ions.  The extent of this type of
reaction is unknown.  Most literature sources seem to indicate the elimin-
ation of free air oxygen will eliminate a large portion of pollution pro-
duction. This means that oxidation is insignificant without the presence
of free air oxygen.

         Underground mines can be developed so  that either flooding or
zero discharge will occur after completion of mining.  This merely re-
quires positioning the openings at the highest elevation and developing
the mine in a downward direction. The openings  do  not always have to
be in the highest position if sealing is planned. The elevation difference
between the openings and the highest elevation of  a mine should be held
to a minimum to insure effective operation of the seal.   The seal  and
the rock in the seal area should be capable of withstanding the  maximum
attainable water pressure.

         Study of local hydrogeological  conditions may reveal that the
                                - 188 -

         Pumping  Required
         During Mining
Underground  Mine
    Water Level
                   Water Level
           Underground  Mine
             DOWNDIP   MINE - AFTER   MINING
                 PREPLANNED  FLOODING
                        Figure 9.2-1
                           - 189 -
             Adapted from drawing
             in reference No. I2I

mine could never be fully flooded.  In these cases, discharge can be
minimized by locating the mine opening above the highest attainable
post mining water level.

         Flooding cannot occur unless an entire mine area is capable
of withstanding imposed water pressure.  Consideration must be given
to the fact that the seal area may not be the weak point.  The down dip
outcrop area, and points where mining approached the land surface,
are potential weak spots.  These areas could physically fail  under  high
water pressures.

         Failure is not the only problem.  The rock units may have
enough permeability that a significant discharge will occur under the in-
creased head.  Sufficient mineral barriers  should remain along the perim-
eter of a  mine to insure flooding.  Consideration should always be giv-
en relative to closeness of approach to the land surface at any given area.
Mineral barriers should also remain between adjacent underground mines
to prevent interflow from  compounding problems.

         This system basically utilizes down dip mining with appropriate
mineral barriers in place.
         Most underground mines were developed to the rise of the mineral
wherever there was a choice of going to the rise or to the dip.  This was
done to facilitate gravity drainage from the mine.  It also allowed full
mine cars to exit the mine under gravity influence, and the empty cars
were then hauled uphill. The majority of abandoned underground coal
mines  in the eastern United States were developed  to the rise.  These
mines  are large sources of pollution and they are extremely difficult to
seal.   If downdip mining had been  practiced, along  with judicious use of
mineral barriers, a large portion of the acid mine  drainage problem we
now face would never have occurred.

         Use of this technique will entail additional costs for underground
                              - 190 -

mining.  Water will collect in low spots and will have to be pumped
from the mine.  Pumping costs will vary greatly.  They can be prohibi-
tive at times, as evidenced by the decline of underground mining in the
Pennsylvania Anthracite Field.  Leaving mineral barriers in place will
cause additional costs because the barriers consist of non-recoverable
         Costs are not presented because of the highly variable nature
of individual mines.   Many mines are presently operating under these
type conditions and would not experience cost increases.

         19,  53, 65, 117, 121, 140, 145, 146, 149, 167, 186
                               - 191 -

                  9.3  ROOF FRACTURE CONTROL
         Most of the water entering many underground mines passes
vertically through the mine roof from overlying strata.  The original
source of this water is  infiltrating rainfall.  Collapse of a mine roof is
sometimes responsible for increased vertical flow, particularly in coal
mines.   Horizontal permeability is characteristically rnuch greater
than vertical permeability in the rock units overlying coal mines.
These rock units generally have well developed joint systems.   These
joint systems tend to cause vertical flow,  except for intercalated beds
of shale  and clay that tend to inhibit vertical flow.  Roof collapse causes
widespread fracturing in the strata around a mine roof, and subsequent
joint separation far above the roof.  These opened joints can tap over-
lying perched aquifers and provide flow paths to the mine. Roof col-
lapse in  shallow mines  will often cause surface subsidence.  Subsidence
fissures collect and then funnel surface runoff directly to the mine.

         Roof collapse is directly responsible for a large portion of the
drainage from many underground mines.  This source of water can be
substantially reduced by using mining procedures that ameliorate the
severity of roof collapse.

         Fracturing of overlying strata can be reduced by employing one
or a combination of the following:

         1)  pillars
         2)  roof support
         3)  limiting the width of openings  in which caving
            will occur
         4)  backfilling  of voids with  materials.

         Pillar mining is accomplished by partial extraction of the  min-
eral resource, leaving  the remaining mineral to support the overburden.
Also, the geometry or shape of an opening can increase stability of a
                               - 192 -

mine roof.  Circular voids reduce stress concentrations that occur at
corners of rectangular voids where shear failures usually develop.
Timbers and roof bolts add additional support.  By limiting the width of
openings, the vertical extent of roof rock fracturing can be controlled.
This should reduce the vertical extent of joint opening, and therefore
reduce the vertical extent of aquifer interception.

         Backfilling consists of filling mine voids with waste  rock  and
other materials to aid in supporting overlying strata.   It is a common
procedure in countries with more limited coal resources. Mine voids
can be filled by solid stowing or by hydraulic stowing.  Hydraulic back-
filling is conducted in some underground metal mines in the western
states, and has also been used in areas with inadequate pillar support
in the anthracite region of eastern Pennsylvania.
         Mining without caving is not feasible for those types of mining
operations, such as block caving, which require caving of roof rock.
However, when mining without caving is applicable, major sources of
water can be excluded from the mine environment.  However, careful
consideration must be given before limiting the  extraction of scarce
mineral resources.

         Controlling fracturing by limiting void  width is best applicable
to linear sedimentary mineral deposits such as  coal.  Methods used to
extract massive tabular mineral deposits do not readily lend themselves
to small void opening workings.  The geologic setting  may provide an-
other restriction to application of this technique.  If there is little verti-
cal separation between the mine and overlying aquifers or the surface,
it is usually difficult to prevent fracturing into these water sources.

         Backfilling used in conjunction with controlled void  width could
be an effective method for preventing interception of overlying water
sources. Backfilling  is limited by availability of suitable backfill ma-
terial,  and the costs and handling problems of transporting the wastes
                                - 193 -

back into the mines.  Some waste materials are structurally incompetent
and will provide little support.  Cyclone separaters have been used in
several hard rock mines in the western states to increase competency.
The cyclone separates sand and heavy fractions from the slime.  The
sand and heavys are used for backfilling, and the slime is then placed in
tailings ponds.
         A mining company would incur profit losses as a result of par-
tial extraction.  The amount of loss will depend on the type and amount
of mineral left as support.  Savings in treatment and pumping  costs can
partially alleviate profit losses.

         Under some circumstances, backfill material costs may be
prohibitive, but it is possible that industrial or municipcd solid wastes
may be available at no cost.  Backfilling  by solid stowing may  cost as
much as 11 percent of the cost of production, while hydraulic stowing
costs could be about 5 percent of the cost of production.  In both cases
it is less costly to backfill during active mining than after  completion
of mining.
          94, 95, 138, 175, 176, 177
                               - 194 -

         Use of this technique is the same as discussed in detail in Con-
trolled Mineral Extraction,  Section 2.10,  in the Surface Mining division
of this  report.

         The central theme  of this method is to shift emphasis from
mining in areas which have  a high probability for causing pollution, to
areas where pollution is unlikely to occur.  Again, it should be under-
stood that pollution potential usually varies greatly, even within small
areas.  Use of this method assumes that advances in technology will
provide for future removal of minerals from high pollution potential
areas,  with less environmental harm than would occur today.
         Effective use of this method would require water quality sur-
veys, core boring analyses, and/or review of existing data to define the
high pollution potential areas.  The state of Ohio is presently engaged
in such a program.
         148,  198, 207,  208
                               - 195 -

         This technique  is similar to mine inundation in that free air
oxygen is eliminated from an underground mine. Pollution production
is reduced through the reduction of oxygen, as explained in Section
9.2 of this manual.

         A feasibility study was made for the Federal Water Pollution
Control Administration by Cyrus Wm.  Rice Division, NUS Corporation
in 1970.   This is a very complex mining method that involves replace-
ment of normal mine atmosphere with an oxygen free, non-combustible
gas.  The mine workers must wear complex life support and commun-
ications systems.
         This system is reported to be feasible.  A pilot scale demon-
stration will develop better feasibility data.  The feasibility report  in-
dicates this system will increase mine safety and  health factors.  This
report should be consulted if additional  information is desired.

         Water pollution control continues only as  long as the oxygen
free atmosphere is maintained.  The mine will revert to normal pollu-
tion production conditions when mining is completed,  unless the oxygen
free atmosphere is maintained.  This is unlikely.  More conventional
means, such as sealing, will probably be utilized to control pollution
after abandonment.  The beneficial affects occur only during mining
activities.  Therefore, the criterion for use of this technique for pui—
poses of water pollution control is economic, based on the cost differ-
ential between using this technique or creating the mine water discharge.
                                - 196 -

         The feasibility study report estimates that capital costs would
increase 12% and that operating costs would remain the same.  An in-
crease in production cost could occur through the use of this technique.
                                - 197 -

                         9.6  DAYLIGHTING
         Daylighting is performed by completely stripping out under-
ground mines. This method is presently in the research and demon-
stration stage. A feasibility study conducted for the EPA indicates
that it is feasible, and a demonstration project is scheduled,,

         Daylighting is carried out similar to strip mining,  and all sur-
face mining pollution control techniques apply.  This technique sub-
stitutes a regraded strip mine for an underground  mine;. Care must be
exercised to ensure that the strip mine does not create  more; pollution
than the old underground mine.
         There are two general prerequisites necessary to make this
technique feasible.  There should be sufficient marketable mineral to
offset some of the cost of overburden removal,  and the  underground
mine should be a documented pollution source.

         To satisfy the first requirement, a complete resource evalua-
tion  should be performed to determine the amount and quality of re-
maining mineral.  The total value of recoverable mineral should be
determined for the mine site.  Costs should then be developed for the
daylighting operation, including mineral and surface rights acquisition.
The  mineral removal costs may exceed the marketing returns.  This
cost differential may then have to be justified from a water pollution
control standpoint in order for the daylighting to be feasible.  Daylight-
ing for many of the deeper mines will not be feasible.

         Use of mine maps to determine recoverable reserves should
                               - 198 -

require the maps to be authenticated. Secondary and tertiary mining
operations often were conducted to recover much of the resource left
from the first stage of mining.  These later operations were not always
         The feasibility of this technique is closely related to produc-
tion cost, and since production cost is similar to that for active surface
mines,  it is recommended that active surface mine operators be con-
sulted during economic evaluation.
                                199 -


    - 201 -


                       10.1 METHOD DISCUSS ION
         These techniques are designed to reduce the amount of water
entering underground mines, and subsequently reducing the amount of
drainage exiting the mine.  These techniques can often be advantageously
employed by  active miners  to  decrease the volume of water that needs
to be  handled  and treated.

         Use of these techniques for abandoned mine water pollution
control is based on the premise that a decrease in the amount of flow
exiting the mine will result in a decrease in the total pollution load.
The pollution  load is the actual weight of specific pollutants passing a
point  within a specified time period.  The load is calculated  by multi-
plying pollution concentration  in the water by the amount of flow,  using
appropriate conversion factors.   Loads are commonly expressed in
the unit kilograms per day (pounds per day).

         In order for this technique to be  useful in pollution control,
the resultant decrease in flow must not be accompanied by a  propor-
tionate increase in pollution concentration.  If such  a trade-off should
occur, the pollution load could remain essentially the same.  This trade-
off is not an entirely unlikely possibility.

         Coal mine drainage will be used  as an example of how this could
occur. Coalmine drainage pollutants result from the oxidation ofpyrite.
Oxygen and water are  required for this oxidation reaction in a non-
flooded mine.  The relative  humidity in an underground coal mine is
usually at or near saturation (100% relative humidity).  Mine walls are
normally damp.  Water required for the pollution forming reaction is
almost always available.  Flushing of the oxidation  sites is not even re-
quired.  Salts resulting from  oxidation are hygroscopic, meaning that
they will draw water from the atmospheric humidity.  The salts will
weep  downward from the accumulated humidity,  exposing the reaction
sites  to further oxidation. The point of this discussion  is that the a-
vailability of oxygen is the oxidation rate  controlling factor, and the
amount of water flowing through the  mine does not control the oxidation
rate.   Pollution production may be constant within the mine regardless
                                - 203

of the flow of water through the mine.  Decreasing flow may result in
increased pollution concentrations.

        Therefore it is possible that decreasing mine drainage could
have little or no effect in controlling pollution.  Decreased flow may
result in decreased water pollution  if the amount of drainage is reduced
sufficiently to prevent pollution transportation from the mine.  In this
case, decreases  in water pollution coming out to the surface could also
result in increases in ground water pollution.

        The techniques discussed in the following sections  can be used
to decrease the amount of water flowing through underground mines.
Choice of technique and extent  of its use will depend on hydrologic con-
ditions in the area and cost effectiveness of the technique.  These tech-
niques are not universally applicable.  Some mines are already receiving
minimal infiltration, and further decreases may be difficult to obtain.

        Infiltration generally occurs as a result of rainfall recharge to
the ground water reservoir. Water can enter from below, or laterally
through the mineral or adjacent rock units.  Rock fracture zones and
faults have strong influence on ground water flow patterns.  They often
collect and convey large quantities of water.  Infiltration can usually be
reduced by avoiding these zones during mining.
                               - 204 -

                 10.2  INCREASING SURFACE RUNOFF
        Water infiltration can be decreased by increasing surface
water runoff.  This technique involves elimination of depressions
and grading the surface to increase water velocities.  Subsidence
depressions often collect and convey large quantities of surface water
to underground mines.  The  amount of water collected  depends on
size of drainage area tributary to the depression, and annual rainfall
and runoff rate.  Subsidence holes in stream channels  can cause en-
tire streams to enter underlying underground mines.  Uneven sur-
faces caused by agricultural, logging or other  surface  activities can
cause increased infiltration.

        Surface runoff can be increased by grading an overlying area
to a smoother, better draining configuration.  Surface depressions
can be filled in and even lined with clay.  Stream channels can be
flumed, reconstructed with impermeable liners, or diverted around
waterless areas.  Channel stability under increased flows must be assured.

        Use of latex as  a soil sealant was demonstrated  as  a means
of decreasing infiltration. It was found to be generally ineffective as
well as expensive .
         Surface water runoff can be increased.  Effectiveness of any
particular application will depend on site hydrology.  Site evaluations
are necessary to determine the amount of infiltration caused by cor-
rectable situations.  Flow measurements can be made to determine
the amount of excess infiltration by comparison with similar adjacent
non-mined or undisturbed areas.
                               - 205 -

        This technique is effective where water is lost in a stream
channel.  Large volumes  of water can often be prevented from entering
underground mines at relatively low cost. The capacity of a flume or
reconstructed channel will have to be large enough to handle heavy rain-
falls.  Local hydrologic data detailing maximum runoff volumes for any
storm over the normal frequency ranges  is usually available.
        Costs are variable, and can only be determined for each
separate area.  Stream rechannelling and fluming costs are detailed
in Section 7.2, Diversion.
         145, 168
                               - 206 -

                   10.3 REGRADING SURFACE MINES
        Surface mines are often responsible for collecting and convey-
ing large quantities of surface water to adjacent or underlying under-
ground mines.  Non-regraded surface mines often collect water in an
open pit where no surface exit point is available.  Many abandoned under-
ground mine outcrop areas have been contour stripped.  These surface
mines often intercepted underground mine workings, providing a direct
hydrologic connection.  The surface mine does not have to intercept
underground mine workings in order to increase infiltration.  Surface
mines on the updip side of underground mines collect water and allow
it to enter a permeable coal seam.  It then flows along the coal
seam to underground  mines. Overlying surface mines that collect and
entrap water can also be significant sources of infiltration.  These sui—
face mines facilitate entry of surface runoff to the ground water system,
which eventually works its way into an underground  mine.

        Hydrogeologic studies can be performed to determine the nature
and extent of infiltration caused by surface mines.   Drainage areas above
surface mines can be determined and flows  calculated.

        A regrading  operation is then designed to conduct flow around
a surface  mine by diversion (and by flumes  if necessary),  and to in-
crease surface runoff.  The regrading operation is the same as discussed
in the Surface Mining division of this manual. Contour regrading
may be preferred in this instance,  because  of its good drainage char-
        Surface mine regrading to prevent infiltration of surface water
                               - 207 -

to underground mines is presently underway In the Dents Run Water-
shed, West Virginia. Reduction  in underground mine flow has already
been reported. The EPA feasibility report for the Dents Run Watershed
is a good source for further information concerning use of this tech-

        Effectiveness of this technique will depend on the amount of
water being entrapped by the surface mine and the effectiveness of the
reclamation work.
        Costs are the same as strip mine contour regrading,  plus di-
version and revegetatton.
                               - 208 -

         Boreholes and fracture zones act as water conduits to under-
ground mines.  They are usually vertical, or near vertical, and tap
overlying aquifers.  They collect and transport ground water.

         Boreholes are commonly present around underground mines
and usually remain from earlier mineral exploration efforts. These
boreholes can be located and plugged to prevent passage of water.  Con-
crete can be inserted hydraulically to form a seal.  Boreholes can be
easily sealed from below in an active underground mine.  Difficulty can
be encountered if sealing has to be performed from the surface.
Abandoned holes are often  difficult to locate on the surface,  and  many
times they will be blocked  by debris.

         Fracture zones are often major conduits of water.  They
increase vertical movement of water and can cause large lateral move-
ments.  Fracture  zones are usually vertically oriented planar type
features.  Their location can be plotted by experienced personnel using
aerial photography.  Permeability of these zones can be reduced by
drilling and grouting.  Holes are  drilled into the zone and grout is in-
serted hydraulically.  Care must be taken to ensure that the boreholes
are located in the  fracture zone at the point of grouting. There are
various types of grout available,  however, concrete is commonly used.
         Boreholes can be successfully sealed.  The seal should be lo-
cated well above the roof of a mine to guard against roof collapse from
additional water pressure.

         Fracture zone sealing in underground mines is theoretically
                               - 209 -

possible,  but documentation of successful applications was not found.
         The cost for sealing a borehole should range from $100 to
$1200 per hole perhaps averaging $600 per hole depending on the size,
depth and condition of the hole.  Grouting generally ranges from $80
to $260 per linear meter ($25 to $80 per linear foot) of grout curtain,
depending on depth of holes, difficulty of drilling, and amount of grout
         9,  54
                              - 210 -

                  10.5  INTERCEPTION OF AQUIFERS
        This technique takes advantage of the natural geologic and
hydrologic systems surrounding a mined area.  It involves use of bore-
holes, casing,  and pumps to transfer water from one point to another
in order to reduce water flow into an underground mine.  The tech-
niques are theoretical and will require  development and demonstration
to establish feasibility.

        A complete hydrogeologic site evaluation of a mined area to
determine aquifer characteristics and water flow systems is required
prior to implementation.  Most underground mines receive water from
overlying aquifers.  Several techniques can be employed to tap these
aquifers and reduce the amount of water entering a mine. Overlying
aquifers can be drilled and the water pumped to the surface. Boreholes
can also be drilled through aquifers, passing through an underground
mine and  into underlying aquifers. The borehole must be cased through
the mined zone (it collects water from the overlying  aquifer, passes it
through the mine zone for discharge to an underlying aquifer).  The
underlying aquifer must be capable of accepting the anticipated flow.

        A variation on this technique is to drill  holes to the under-
ground mine, case the last zone from the deep mine  opening up into
the roof.  The boreholes are then connected by pipes and the water
carried outside the mine.  The uncased portion of the borehole collects
water from overlying aquifers and passes  it into the  piping system for
conveyance out of the mine, never contacting pollution forming materials,

        Boreholes, pumps and piping systems can also be used to con-
vey acid mine drainage to a nearby alkaline aquifer,  or alkaline under-
ground mine, to encourage mixing, neutralization and settling of pre-
cipitates .
                               - 211 -

 Wells ~
                                             Ground  Water  Level

                                                  Ground  Surface

I*- Casing
                                        Confining Bed
                                        Underground  Mine
                                        Confining  Bed
       JL Deep    II   Aquifer
      ^   fj  ~>~~ - ^ -^ J< ^^
         M     '       j       —^
                                                Free  Water
                                              /" Surface

                                            ~ ^— rr r  , ,   V
                 Free Water /-Ground
                 Surface^/    Surface
                       Mine  Drainage
                           Seepage Face'
                         Figure 10.5-1
                                              Adapted  from drawing
                            - 212 -           in  reference No. I2I

 Well Points
          Ground Surface
             Original Ground
             ".Water  LeveJ
p Free
 ;:j Water
 in Surface
                        Underground  Mine

        Well  Points
           Original  Ground.
              Water Level
      I      i

                               Underground  Mine
                              r- in  Regional
                             t \ Ground - Water  Discharge

" "MC M!	
                        ...  H.
                  Source   Bed
                      Figure 10.5-2
                                         Adapted from drawing
                        - 213 -          in reference No. I2I

         Use of these systems is highly technical. Therefore, aground
water geologist should be consulted to perform site evaluation, deter-
mine feasibility,  and design the system.

         These techniques are not universally applicable, and will work
only under favorable circumstances.  System design will be variable,
depending on local hydrogeologic factors.
        Costs can only be developed on an individual application basis,
                               - 214 -

     - 215 -


                       11.1  METHOD DISCUSSION
         The techniques available for waste water control are identical
with the techniques discussed under this same heading (Section 5.0) in
the Surface Mining division of this report.

         One different technique—construction of drainage tunnels—is
discussed in this section.
                               - 217 -

                       11.2  DRAINAGE TUNNELS
         Drainage tunnels have been constructed in western hard rock
mines and eastern anthracite and bituminous coal mines.  They are
purposely driven to dewater mining complexes by means of gravity
flow. Existing drainage tunnels sometimes originate in a watershed
adjacent to the mined watershed.  Tunnels are driven from a low point
upwards at a slight angle to intercept the lowermost mine workings.
They are usually constructed when mining  is impeded by water prob-
lems. Drainage tunnels are often connected to many mines, and serve
as a common gravity drain, permitting mining to continue  to lower

         The drainage tunnels are normally a pollution  source, because
they interconnect many workings over a large elevation differential.
They are difficult,  if not impossible, to seal and they make it difficult
or impossible to seal individual mines.

         Drainage tunnels can be used in water pollution control in
special  instances, where it would be necessary to collect and treat dis-
charges from many mines within a mining  complex.
        A drainage tunnel could be driven to collect the combined dis-
charges of many mines in order to consolidate the flow for treatment at
one point.

        A study would be necessary to be sure installation  of a tunnel
would do more good than harm. Use of a tunnel would be based on eco-
nomics.  A tunnel could be employed where it would be cheaper than
                               - 218 -

using conventional surface collection devices.

         A variation of the tunnel concept would be to break into a
deep mine to cause the discharge to exit at a point more advantageous
for treatment plant installation.
         Costs are variable and must be developed on an individual
application basis.
                               - 219 -


 - 221 -


                     12.1  METHOD DISCUSSION
         Mine sealing is usually employed to promote inundation of
underground mine workings to reduce oxidation of pyritic materials.
Seals have also been used to prevent the entrance of air or water to
the underground mine.

         Mine sealing for purposes of inundation  involves construction
of a physical barrier in a mine opening to prevent passage of water.  A
barrier must be designed to withstand the maximum expected pressure
(head) of water that will be  exerted against it.  Sealing underground
mines is somewhat analogous to creating a surface water impoundment:
a major portion of the dam  structure would already be in place and the
seal merely closes the opening.  Engineering considerations are also
similar to these for surface impoundment design.  The entire dam struc-
ture must be capable of withstanding exerted pressure, and leakage rates
must be determined. Underground mine seals have seldom been success-
ful due to lack of consideration of leakage rates and weak points.  Seals
can be designed to withstand a large amount of pressure, but the seal is
only a small part of the impoundment structure.  The perimeter of the
mine forms most of the impoundment, and often  it  is not capable of with-
standing any significant amount of pressure.

         The first step in mine sealing  is to obtain and analyze all
pertinent available site data including:

         1)  Geology
         2)  Mine Maps
         3)  Locations of Sink Holes
         4)  Hydrologic Data
         5)  Rock Hydraulic Characteristics
         6)  Borehole Logs
         7)  Location of Strip Mines
         8)  Outcrop Lines
         9)  Mineral Structure Contours
        10)  Aerial Photogrammetric Mapping
                               - 223 -

Sealing feasibility and practical limits of inundation are then deter-
mined.  Limits of the expected mine pool are plotted on a mine map.
Areas where water pressure will be exerted are then delineated, in-
cluding the expected pressure to be exerted for each area.  Hydraulic
evaluation of all pressure areas is required to determine if existing
barriers are capable of withstanding the applied pressure.  Areas
deemed incapable of withstanding the anticipated applied pressure
must be evaluated further.  This evaluation is to determine whether
additional measures, such as grouting, would be successful  in ren-
dering the areas capable of withstanding expected water pressure.  If
the required work is technologically or economically not practical,
the desired  mine  pool level will have to be lowered, or the sealing
program abandoned.

        As previously stated, mine seals can be designed to hold
reasonable heads of water. Mine  sealing problems generally occur
from natural weak spots such as the outcrop, fractures  and subsidence.
The mineral and natural rock systems around underground mined areas
usually become more permeable due to the nature of the rock and the dis-
turbance caused by mining.

        The outcrop area normally is the weakest link In an under-
ground impoundment.  The mineral outcrop is generally of non-uniform
thickness.   Mining approached very close to the outcrop in some areas,
resulting in very little material remaining to withstand any water pres-
sure. Surface mined crop areas are seldom capable of withstanding
significant water pressure.  Mine roof collapse in a flooded  zone will
provide highly permeable zones, allowing water to escape, thus pre-
venting extensive flooding.  Physical failure of outcrop areas will
sometimes occur, but more often  the increased pressure results in
seepage through the  permeable zones, preventing significant cimounts
of water level increase. Water can also be lost through the  mine

        The second step in mine sealing is to determine the ability of
the natural system to withstand water pressure.  The ability of a natu-
ral barrier  to withstand pressure  can be increased by use of grouting
and sealing  subsidence holes.  The practicality of implementing these
procedures  will have to be evaluated.
                              - 224 -

         Unfortunately, precise data is seldom available for evaluation
of mine conditions.  The engineer designing the system may have in-
adequate knowledge of how the natural system will react. The  hydro-
logic characteristics of mined areas are highly complex and variable
from mine to mine.  The natural response of the area to changes in
hydrostatic pressure is even more complex,  and is difficult to  approx-
imate without voluminous amounts  of data and computer analysis.
Mine sealing decisions and design are therefore judgmental projects
that should involve personnel that are expert in mine and ground water

         A mine seal can be constructed in  many ways, using many
different types  of material. Any material capable of withstanding water
pressure has theoretical application.  A mine seal must have internal
strength capable of withstanding the water pressure, and it must be
tied into the floor, roof, and sides of a  mine opening.  Sufficient in-
ternal strength is  easily obtained.   Physically anchoring the seals to the
mine opening is much more difficult.  Many mine seals leak around
their edges due to poor anchoring.

         The natural  rock and mineral surrounding the seal area is
usually fractured, fissured, uneven and unstable.  Leakage occurs
through this permeable zone because of the inability of most seals to
penetrate surrounding materials.  Most mine seals are incapable of
providing effective sealing between the top of the seal and the roof
rock.  Extensive grouting directly around the seal area can help to
tie the seal into the surrounding rock and reduce perimeter leakage.
Grouting should occur very close (within 1 meter) to the sides of
the seal and directly  into the overlying roof to insure effective  grout
penetration.  Curtain grouting extending outward along the outcrop
from the seal is usually employed with most mine  seals where  appre-
ciable heads are expected.  This serves to  decrease permeability and
reduce the amount of leakage that is bypassing the seal.

         Seal failure has also occurred due to its being constructed  in
moving water.  Water flow should be stopped prior to placement of a
seal, especially when using liquid or alkaline sealants such as  grout,
concrete or gel.
                              - 225 -

Flow can be stopped by pumping an existing mine pool (if one is present)
or by construction of an impounding dike and piping system behind the
seal area.

         Mine sealing can be a very dangerous operation.  T'he ultimate
water level behind the seal is seldom controlled, and excessive water
pressures  can build up, resulting in a mine seal or outcrop failure.
Sudden release of large quantities of water can have devastating down-
stream effects.  Subsequent flooding can and has caused loss of life
and massive property damages.  Release of large quantities of polluted
water can also result in far-reaching downstream fish  kills,

         Excessive increase in water pressure can  be prevented through
use of boreholes drilled into a mine pool area from above. Boreholes
are drilled from a surface elevation equal to the maximum permissible
mine pool elevation.  Boreholes should be cased and protected  to insure
that they remain open.  When the  mine pool reaches the maximum ele-
vation, the boreholes begin to flow and thus prevent further water level
increase.  Boreholes must be of sufficient size and distribution to be
capable of  transmitting the greatest expected inflow to  the mine pool
without allowing further water level rises.  This is a natural, gravity
operating system that does not require supervision.

         A mine pool drawdown system should  also  be installed during
mine sealing. This usually consists of a pipe constructed through the
mine seal which has a manually operated valve.   When the valve is
opened,  water can flow through the seal,  lowering the pool elevation
to its original pre-sealing level.  This is mainly a safety device, but
it could be used to drain a mine pool if future mineral extraction should
be desired in a flooded  area without destroying the seal.

         Special legal considerations are involved in mine sealing.
Adjacent mineral extraction  is often difficult or  impossible after seal-
ing.  Mineral rights owners may have valid damage claims.  The extent
of damage  is often difficult to establish and could lead to prolonged
legal disputes. Mine sealing in arid and semi-arid regions could in-
fringe on the water rights of downstream users.  Mine water,, even
though of marginal quality, is a valuable resource in some areas.
                               - 226 -

        Many of the sealing techniques described in the sections fol-
lowing have not had notable success in mine water control.  In most
cases the  lack of success is not due to failure of the seal itself.  The
lack of success is more often attributable to the manner of placement
and lack of proper consideration for the natural system.
                               - 227 -

                    12.2 DOUBLE BULKHEAD SEALS
        The technique involves placement of two retaining bulkheads
in a mine opening followed by placement of a seal in the space between
the bulkheads. Bulkheads can be placed from a mine portal,  if it is
open and accessible, or through vertical boreholes from above.  Grout
or concrete is then placed between the bulkheads via pipes through the
front bulkhead, if accessible,  or from vertical boreholes.
                           E»i*ling Ground
                       CROSS  SECTION   OF
                    DOUBLE  BULKHEAD  SEAL
                             Figure I2.2-I
                                          Adapted from Drawing
                                          in reference No. 54
                                - 228 -

         Two types of double bulkhead mine seals have recently been
successfully demonstrated.  In Inaccessible mine entryways a grouted
seal has been used, and for accessible mines quick setting concrete
seals have proven effective.

         Grouted double bulkhead seals have been recently constructed
at Moraine State Park,  Pennsylvania, under the state's "Operation
Scarlift" reclamation program. This method utilized dry, coarse
aggregate for front and rear bulkheads placed through drillholes. The
bulkheads were then grouted to form solid front and rear seals.  Water
was pumped  out of the center cavity between the two bulkheads  by new-
ly placed drill holes. Concrete was poured into the space  between the
two bulkheads.  These same mine seals have also been successfully
installed without grouting the retaining bulkheads.

         Use of double bulkhead seals for accessible mine entries has
been attempted only a few times, primarily by the Halliburton Company
under  contract to the EPA. A quick-setting slurry consisting of water,
cement, bentonite and sodium silicate was  used to construct the two
bulkheads.  The void between the bulkheads was filled with a special
light concrete composed of portland cement, fly ash, bentonite  and
water, pumped through a grout pipe.  In another case, this void was
filled with pneumatically pumped limestone aggregate, which was then
grouted with light concrete.
         These seals have been successfully demonstrated and appear
capable of withstanding relatively large amounts of water pressure.
The maximum pressure exerted has been limited to 10.7 meters (35
feet) of head.  However, these seals should be capable of greater pres-
sures as installation procedures  improve.

         Grout curtains are required for total effectiveness.  Seal
leakages generally occur  through the bottom and around the sides of
a seal.   It is difficult to get a good seal at the mine roof because of
slumping.  The perimeter of a seal should be well grouted.  Special
grouting procedures are explained  in Section 12.5.
                               - 229 -

         Double bulkhead seals without curtain grouting range in cost
from  $7,500 to $15,000 per seal.  These seals have cost as nnuch as
$50,000 in certain instances.

         Quick-setting double bulkhead seals in accessible entry mines
average $9,500 per seal without curtain grouting.
        9, 31, 54, 140
                               - 230 -

                         12.3  GUNITE SEALS
         This technique involves use of gunite, a pneumatically-placed
low slump concrete, to rapidly and effectively seal mine openings.  Gun-
ite is projected by an air jet directly into place and,  by proper adjust-
ment of the mix and nozzle, will stand vertically eliminating the need for
forms. An area is selected for the  seal within sound or reasonably
sound zones and the roof, sides and floor are shaped so that the space
will  be a form for a tapered gunite "plug" and to provide clean surfaces
against which to construct the seal.   A wood bulkhead is constructed of
the inner limit of the seal to support the initial placement of gunite.
The  seal is then constructed by placing successive thin layers of gunite.
Care must be taken to remove "rebound" from the floor as construction
progresses to avoid a permeable zone in that area.

         A seal constructed by this process completely fills the opening
in which it is placed and should provide an effective seal, particularly
if an expansive type cement is used.  Since the seal is pneumatically
placed against the perimeter of the opening (which has been first shaped
and cleaned) and  since the shape of the seal is  such that it becomes
tighter as the pressure against it increases without relying on flexural
characteristics,  it should be particularly effective in sealing against
higher hydraulic  heads.

         A gunite underground mine seal will be demonstrated in the
Cherry Creek Watershed by the State of Maryland and the Appalachian
Regional Commission in the near future.
         This technique shows promise of being an excellent underground
mine seal.  The seal forms a good bond with the mine opening.  How-
ever, grout curtains are still deemed necessary.
                               - 231 -

                                              Limits of Seal
                                                    Sldewall -
                                        ~. '•  ' .'. Present Sldewotl -^. * '••.• '•
                                      • f. -•" '-,  .  *,..--*:•• 4 '-«:.•
                                        v*  .•.   •.•'•   -
                                        'A'     .    'A   .- '   .  .
                                       ' •  . •• '• A .'  •'.  . .  ft • • /  ft •'•.•.
 • . 4  '
                                       ,  •' i :  .*  •••'*  '•>'  * '••  .
                                       'ft  :^ - ; t Present S/atwa//-<  • 4 •
-Wood    S
                                           Limits  of  Seal
                                                              .     !
                                                   'Rock Roof^    I
  i-. ... .	fT~^^ ~
 \.i .-,*.'<  . y  >*
-  . • i_.  ^   4  ^jPresent Floor  ' t
•» *..'•"'),'•/ /\°'"* ^"/'"y A • • j,
                                                                                     Cut floor, celling and walls to
                                                                                     outline shown and Install
                                                                                     pneumatically placed concrete
                                              ~ Clay Floor ~-
              SECTION  "A-A"

             Figure   12.3-1
                                                     - 232 -

         Costs will generally average $260 per cubic meter ($200 per
cubic yard) of gunite installation.  (Excavation, cleaning, and shoring
in the mine opening will entail additional expense.  A complete gunite
seal in a standard mine opening is estimated to cost $13,000.
                               - 233 -

                    12.4 SINGLE BULKHEAD SEALS
         Single bulkhead mine seals are generally composed of a grouted
aggregate bulkhead.  They can be constructed of other materials,  such
as masonry block.   The seals are placed remotely by using boreholes
from above, or constructed directly in the opening, if accessible.  Ex-
ploratory and observation boreholes are used for remote installation to
determine the size  and condition of the opening,  and to locate the best
sealing location.
                                              Header Timber


                                              Ground Surface
                              CROSS  SECTION  OF
                             SINGLE BULKHEAD  SEAL
                                  Figure I2.4-I
                                              Adapted from drawing
                                              in reference No I35
                                 - 234 -

         An aggregate bulkhead is placed either through vertical bore-
holes or directly from the mine opening. The aggregate is then grouted,
using a quick-setting slurry composed of water,  cement, bentonite and
sodium silicate.  The slurry is introduced either through pipes inserted
into the mine opening or vertically through boreholes from above. The
aggregate usually slumps away from the mine roof during grouting, and
additional grout must be added.  Curtain grouting is usually needed to tie
the seal to the surrounding rock and mineral.
                                Ground Surface
               1.9cm to 3.8cm   Less than
               (%" to \Vz")   0.95cmW
                           CROSS  SECTION OF
                                Figure 12.4-2

                                         Reference No. 65
                                - 235 -



                     Ground Surface
                                             Drill Holes For
                                             Injection of Slurry
                                                   Mine Void, Side View
                                    Side View
                                             Isometric View of Mine Void
                                             Showing 2B Stone & Holes
                                             For Line Grouting

                                   Figure 12 4-3     Adapted from drawing
                                                  in Renn. Dept of  Environ-
                                                  mental Resources Contract
                                                  No. SL 151-IA
          Single bulkhead seals utilizing a concrete block wall have also
been used.  These walls are highly susceptible to damage  and could not

be used where high water pressures are expected.
                                     - 236 -

         The grouted aggregate single bulkhead seal has been success-
fully demonstrated.  Some of these seals were unsuccessful, but this
was possibly due to poor anchoring with the existing rock and mineral
or incomplete grouting of the aggregate.  These seals should be used
where the expected water pressure will be low. The double bulkhead
seal is better for high pressure.

         The concrete block seal has only limited usefulness, under low
head conditions.  Long term  effectiveness of a concrete block wall is
questionable.  A concrete block wall seal can be strengthened and pro-
tected from weathering if earth is backfilled against it.
         Accessible entry aggregate seals cost approximately $3,500

         Remotely placed aggregate seals cost about $2,100 each.

         Concrete block wall seals cost in the range of $1400 to
$6000 each.
        54, 65, 135, 140
                               - 237 -

                       12.5 GROUT CURTAINS
         Grout curtains are used in conjunction with other types of mine
sealing to reduce permeability around a mine seal and other seepage
areas.  Grouting is only applicable where void areas are small.

         Grout is commonly used around, and extending away from, mine
seals.  It tends to fill voids between a mine seal and the mine entryway,
and to decrease permeability in adjacent rock.  This will reduce seepage
bypassing a seal area.   The grout is generally pressure injected from
boreholes placed on 3 meter (10 foot) centers.  Pressure forces the
liquid grout from the borehole  into permeable zones of the rock units.
The grout sets or solidifies in  small voids and greatly decreases perme-
ability.  Effectiveness of grouting is difficult to determine during the
operation.  There is no way of knowing where it  is going and where it is
collecting.  The three  meter center spacing  is somewhat arbitrary: the
spacing should be sufficient to  ensure the entire  space between  holes re-
ceives grout.

         Grout curtains can also be placed in areas of permeable or
weak outcrops during mine sealing.  This serves to decrease; leakage
rates and strengthens the outcrop to decrease failure possibilities.
         Grout curtains have been successfully utilized many times.  The
success of grout curtains in leak areas has not been documented by be-
fore and after flow recording, but it is said to be effective.

         Efficiency of grout curtains is dependent on the; manner of in-
jection.  Effectiveness may be increased by use  of packers to grout
                               - 238 -

                                     Grout Curtain  Holes 75cm (3") dia. on
                                     Alignment  Parallel  To 8 Approx.
                                     Halfway  Between  Front and Rear
                                     Bulkhead  Drill Holes. Minimum
                                     Of  15.2 M(50') On Both Sides  of the
                                     Mine Entry.
"and/or Pump
 Drill Hole
 Location To Be
 Determined  In
               Distance  Between  Front  And Rear
               Bulkhead  Alignment Range 6.1 M to
               76M (20'to 25') As Directed By Engineer
        Jnjection Hole  ft
         Curtain Grouting
                                                       TO PORTAL
  Figure 12.5-1
                                          BULKHEAD  SEAL
                                           Adapted from  drawing
                                           in  reference  No. 54
                            -, 239 -

individual zones, instead of attempting to grout the entire hole atone time.

         Grout effectiveness can be further enhanced by varying the vis-
cosity at the mixer.  The viscosity is increased in permeable zones and
areas with larger voids. The machine operator can tell when viscosity
changes are required by observing flow rates.

         Grouting is more effective if aggregate is placed in large voids
encountered during drilling.

         Grouting will also be more effective if the first grout holes are
placed within 1 meter (3 feet) of the seal.  Grout holes should be drilled
into the seal from above.  Contact of a mine seal with the roof and sides
of a mine opening is a weak spot where  leakage commonly occurs.  Ex-
tensive grouting  in these areas will improve effectiveness of a seal.

         If there is a possibility of a leak in the bottom  of a mine seal,
the holes drilled into the top of the seal  should continue on through for
grouting the bottom of the seal.  The bottom of a  concrete seal is  likely
to leak if it  is placed in moving acid water.  Flowing acid water can
dissolve cement, leaving behind porous  sand and  aggregate.  Remotely
placed double bulkhead seals may leak at the bottom. Slumping of the
front and rear retaining piles of aggregate may introduce aggregate in-
to the bottom of the center void.  The concrete center plug material
may be unable to flow into this aggregate, leaving a  permeable zone.
         Grouting curtains generally cost in the range of $80 to $260
per meter ($25 to $80 per linear foot) of curtain.
         9, 54
                                - 240 -

                           12.6 CLAY SEALS
         Clay can be used to form a hydraulic underground mine seal
where low water pressure  is expected.  The mine opening is first cleaned
of debris and loose rock.    Clay is then compacted into the opening to
form a seal.  A good quality plastic clay should be used to ensure im-
permeability, and to enable the clay to flow into cracks and voids along
the walls and  roof of the seal area.  Hand placement and compaction
would probably yield a better anchor between the plug and the seal area.
Earth should be backfilled  and compacted around the mine opening and
over the seal  to hold it in place and prevent the clay from flowing under
                       -Original Ground  Surface

                          • Diversion Ditch
                                     Backfilled Ground Surface
                              CROSS  SECTION  OF
                                  Figure I2.6-I

                                         Adapted from drawing in
                                         reference No. 135
                                  - 241 -

         This should prove to be an effective and inexpensive mine seal-
ing technique for low water pressure installations.  The mine opening
has to be accessible in order to use a clay plug.  Effectiveness of the
seal will depend on quality of the clay, manner of placement, and physi-
cal condition of the seal area. Clay seals may be capable of withstand-
ing 10 meters (approximately 30 feet) of head of water under ideal con-
         Costs will depend on availability of suitable clay, its acquisition,
and transportation costs.  Costs will also vary in response to difficulty
in preparing the seal area, and the installation. Costs will generally
range from $1,200 to $4,000 per seal.
         9, 54, 135, 147
                               - 242 -

                12.7  PERMEABLE AGGREGATE SEAL
         Permeable aggregate underground mine sealing involves use of
ungrouted alkaline aggregate material that will neutralize acid water
passing through it.  This causes formation  of precipitates,  which pro-
gressively clog the pores in the aggregate.   Theoretically,  the pre-
cipitate continues to form and  clog all of the pores in the aggregate,
until the permeable aggregate  seal actually becomes a solid,  single
bulkhead seal of aggregate and precipitate material.
                                  Ground Surface
                              CROSS  SECTION  OF
                                  Figure I2.7-I
                                         Adapted from drawing
                                         in reference No 65
                                 - 243 -

         An example of this technique is use of limestone aggregate to
seal underground coal mines that discharge acid mine drainage.  Here
the acid water is neutralized during its flow through a limestone aggre-
gate plug, causing iron hydroxide and calcium sulfate to precipitate,
filling the pores of the aggregate and producing a solid bulkhead type

         Limestone aggregate seals were demonstrated by the EPA in
West Virginia.
         The seals helped attain various degrees of mine inundation.  A
1 .8 meter (6 feet) head of water was reported behind one seal.  The seals
continued to leak, meaning that precipitates have not completely clogged
the pores, or the precipitates are unable to withstand the water pres-
sure.  Increases in pH and alkalinity, and decreases in acidity of the
discharge, showed the neutralizing ability of the seal.  The neutrali-
zation is only temporary and is expected to decrease as the limestone
aggregate becomes coated with precipitate.  The long term value of
this type of seal would be due to its capabilities to withstand water
pressure and cause inundation. Its long term capabilities in this re-
spect have not yet been demonstrated.

         Slumping of the aggregate,  causing an opening at the mine
roof, has been a problem.  Grouting of the opening  may help solve
this problem.
         Costs incurred by the Halliburton Company in two acid mine
drainage related experimental applications were $3,048 and $8,463
per seal.  Michael Baker's report suggests use of an average cost
                                 244 -

estimate of $7,500 per seal. Costs of other mineral industry appli-
cations of the technique would be determined largely by the aggregate
materials used.
        9, 65, 140
                               - 245 -

                       12.8 GROUT BAG SEALS
         This method of underground mine sealing involves placement
of expendable grout containers to seal accessible mine openings.  Seals
are constructed by a vertical series of cement grout slurry filled nylon
or cotton bags, which decrease in length from bottom  to top of the entry-
way.   The container placed on the floor of the entryway is 6.1 meters
(20 feet) long, with other dimensions matching those of the mine itself.
The container is positioned in the mine and filled with slurry, which
causes it to conform to the shape of the mine opening.  As  each container
hardens, a new, shorter one is placed above it and filled with slurry.
This process is repeated until the top container, measuring about 3.1
meters (10 feet) in length, has been positioned and filled.
                                              Jrotn Piptf
                                              with Cap or
                              CROSS SECTION OF
                           EXPENDABLE GROUT  RETAINER
                            UNDERGROUND  MINE SEAL
                                  Figure I28-I
                                          Adapted from drowmg
                                          in reference No. 65
                                  - 246 -

        A grout bag seal was unsuccessfully demonstrated near Coal ton,
West Virginia. Leakage occurred around the contact between the bags
and the mine entryway.  Leakage increased as erosion widened the gaps.
The grout bags will not conform well to an uneven surface and will not
penetrate the many cracks and fissures.  Efficiency may be increased by
means of concrete grouting around the seal.

        Other mine sealing techniques such as gunite or double bulkhead
seals appear to be more  efficient.
         Costs for one experimental installation were $3,300 per
         9, 65,  140
                               - 247 -

                    12.9  REGULATED FLOW SEALS
         This technique is designed for use with treatment plants in
order to maintain flow at a constant level from underground mines.
The seal is used to back up excess flow within a mine during peak
flow periods  where complete mine inundation is impractical and treat-
ment is required.  This technique is  theoretical; its use has not been

         Underground mine flow rates are variable and depend on the
response characteristics of individual mines to seasonal rainfall vari-
ations.   Near surface mines usually  have sporadic (flashy) flow vol-
umes,  indicating short response times.  Treatment plants are nor-
mally designed to handle the largest  expected flows when complete
treatment is  needed. The treatment plant's capacity is then usually
much larger  than the average flow from the mine.   Extra costs are
involved in constructing a treatment  plant to handle large flows.  These
extra costs may be eliminated by  constructing a mine seal which in-
cludes a pipe network to the plant. The mine pool will rise and fall
with seasonal variations in rainfall,  but the treatment  plant will con-
tinue to accept average flow.  This technique would also allow the
treatment plant to cease operations during  repairs without allowing
discharges of polluted water.
         Feasibility of this technique depends on the economic differ-
ential between savings in treatment plant installation and operation,
and costs of mine seal installation. The mine must be capable of
being sealed, and the pool capacity should be sufficient to impound
water during periods of maximum  rainfall.
                               - 248 -

         Costs must be developed on an individual application basis.
                               - 249 -

                     12.10  SUBSIDENCE SEALING
        Mine subsidence holes can be active leak areas after a mine
sealing program.  Sink holes that are lower in surface elevation than
the mine pool elevation are possible leak zones. These areas can be
sealed using  clay, concrete, or by grouting.

        Documented cases of subsidence sealing to prevent leakage
from below are unknown.  However, subsidence  holes have been
sealed to prevent surface waters from entering deep mines.

        The  subsidence holes should  be cleaned of soil and surface
debris with a backhoe or similar device. The underlying fractured
rock can be grouted if necessary.  Clay can then be compacted into
the depression.  Concrete would probably be more applicable than
clay if high water pressures are expected.
        Documented cases are unknown.  These seals would be cap-
able of withstanding various amounts of water pressure,  depending on
the manner of installation and the soil and rock condition.
                              - 250 -

                           12.11  DRY SEALS
         A dry seal is an underground mine seal constructed by grading
earth over a mine opening, or constructing bulkheads consisting of
clay or block walls.

         Dry seals are not meant to be used in mine openings discharg-
ing water. Their function is to prevent entrance of water and air Into
a mine.  They have been used extensively in conjunction with air sealing
programs.  They should not be used where any significant amount of
water pressure is likely.
        These seals have only limited usefulness in water pollution
control. Air sealing does not appear to be effective, therefore use of
dry seals  in conjunction with an air sealing program is not effective.

        They do have application in instances where surface water is
entering an underground mine opening. A dry seal can be used to keep
the surface water out of the mine.

         Dry seal costs range from $100 to $500 for regradlng, $1,200
to $1,500 for clay bulkheads,  and $2,200 to $5,100 for masonry bulk-
heads .
                              - 251 -


                        12.12  ROOF COLLAPSE
        This technique is to be demonstrated by the EPA in the Elk
Creek Watershed, West Virginia.  It is not meant to be used as a pri-
mary mine sealing technique.  It has limited use under special situ-
ations.  The  purpose of roof collapse in Elk Creek is to partially in-
undate underground mine workings, and to partially neutralize  acidic
underground  mine waters.  It will be used on a Pittsburgh coal seam
underground  mine that has a non-acidic clay stone (soap stone) roof
containing stringers of limestone.  The limestone  is locked into the
roof material and is not presently available for neutralization.  Ex-
plosive collapse of the roof will bring some of the  limestone  into con-
tact with acidic underground mine waters.  The physical characteris-
tics of the clay stone are such that it will also restrict the flow of under-
ground mine  water,  causing impoundment, and some acid forming strata
inundation.  Mine roof collapse is only a partial control technique,  and
it will be used in conjunction with alkaline strip  mine  regrading (Sec-
tion 6.12) and slurry trenching (Section 6.13).

        Accurate mine maps, or a test boring program, are neces-
sary to determine the best placement of explosives.  Boreholes are
drilled to a pre-determined height above the mine  roof.  Explosives
are set in the boreholes. The holes are then plugged to direct energy
in a downward direction.
         This technique is only capable of a minimum amount of flood-
ing, and should be accompanied by other water pollution control bene-
fits such as the above-mentioned neutralization.  Its use is limited to
areas where mine roof materials are capable of obstructing flow.
                               - 253 -

Use with a blocky sandstone or shale roof would not be helpful  in re-
stricting mine flow because of the permeable nature of these materials,
Roof collapse should never be used where roof materials are pollution
forming, as commonly occurs in coal mines.  Normal care in  use of
explosives is necessary to prevent damage to structures.  There
should not be any structures overlying or adjacent to the work  areas.
        Costs are as yet unknown and will depend on the number and
size of boreholes required, cost of explosives, setting charges and
sealing boreholes.
                               - 254 -

                                12.13  AIR SEALS
          Air seals are structures placed  In discharging underground
mine openings that permit water to exit from a mine without allowing
air to enter.  The non-discharging openings in the mine are also
sealed by other conventional dry sealing techniques to prevent entry
of air.  Drill holes  in the mined area are also plugged.
                                    Into firm rock
                                 /, — Concrete
                                   •• — Acid Resistant Coating
                                        •To Design Height and Size

                                 AIR   SEAL
                                Figure  I2.I3-I
                                           Handbook of Pollution Control
                                           Costs in Mine Drainage Manag-
                                           ement, U.S. Dept. of Interior,
                                           Federal Water Pollution Control
                                           Administration, I966.
                                   - 255 -

         An air sealing program is designed to prevent influx of free
air oxygen into an underground mine.  Free aLr oxygen is ressponsible
for most of the pyrite oxidation,  which is responsible for acid mine
drainage.  Elimination of free air oxygen is, therefore, the most
desirable method of underground mine water pollution, abatement.

         Many air seals were placed in eastern  coal mines  in the  1930's,
Several air seals  have been placed more recently.

         The seals are constructed of  various materials, but their
operation is based on the same principle employed by using traps in
plumbing systems.
         There has not been much documentation of the effectiveness of
older air seals.  Many of these seals have been destroyed, and many of
the remaining seals are discharging large quantities  of pollution.  There
is no documentation showing the newer seals to be effective.

         It is reasonable to conclude that air seals are not effective for
two reasons.  The underground mines have numerous air passages such
as surface mines, boreholes, joints, fissures and mine subsidence
cracks that allow passage of air into and out of underground mines.
Changes in atmospheric pressure outside the mine causes a pressure
gradient, resulting in air flow into and out of the underground mine.
        Costs generally range from $3,100 to $5,000 per seal.
                              - 256 -

                      12.14 GEL MATERIAL SEALS
         The technique Involves use of commercially available grouts
with a cheap filler material to remotely seal mine voids through bore-
holes without benefit of retaining bulkheads.  The only attempt to use
a gel material as a mine sealing agent was made in a high flow mine
entryway, and failed.  This mine sealing attempt did indicate that use
of gel for sealing low flow and dry mine entrys may be possible.
         The cost of the gel materials proved to be greater than ori-
ginally estimated.  The cost of this seal  is not competitive with other
sealing techniques.  This technique has not proved feasible for use.
         The costs of the gel material alone is estimated at $9,000 per
seal. The sealing operation would add considerably to the total cost.
                               - 257 -

                     12.15  COAL MINE SHAFT SEALS
          A shaft is a vertical or near vertical entryway to an under-
ground coal mine. The presence of a shaft implies that there is no coal
outcrop in the vicinity.  Lack of an outcrop usually increases the prob-
ability of success of a sealing program.
                 Original Ground /
                     CiirfnrA	'
                     Surface -
                  (Approx. 30'Thick)
                  (Appro*. 2' Thick)_

                  (Approx 10'Thick)

                  (Approx. 2'Thick)~
                                               Misc. Fill
Bentomte, Shale 8 Clay


Concrete Plug


Misc. Fill
                           CROSS SECTION OF SHAFT SEAL
                                     Figure I2.I5-I
                                    - 258 -

         Discharging mine shafts are common in eastern coal fields.
Coal mine shaft sealing is generally more successful than drift or slope
sealing.  Rock around the seal is less likely to leak because of low
vertical permeability in the undisturbed coal strata.  Shaft seals are
theoretically able to withstand much more pressure than outcrop seals,
and large amounts of mine inundation can be accomplished.  The degree
of success  of a shaft seal is partially dependent on depth of the mineral
below the surface.  Very deep underground mines can be successfully
sealed.  Leakage is more likely from shallow  underground mines.  A
complete hydrogeologic evaluation is required to determine the feasi-
bility of shaft sealing.

         The shaft is first opened and cleared  of debris. A suitable
sealing zone within the shaft,  such as a sandstone bed,  is selected for
sealing.  Any flow from the shaft is stopped by pumping the mine pool.
Miscellaneous fill is placed in the shaft up to the sealing level.  The
seal of clay and/or concrete is then placed. The shaft should be back-
filled to the surface.
         Shaft seals have been placed,  but documentation of their effec-
tiveness could not be found.  This technique should be highly effective
in underground mine  inundation when used under favorable mine condi-
         The cost will be highly variable,  depending on site conditions,
condition of the shaft, size of the shaft and any auxiliary work required.
                                - 259 -

         Shaft seals will generally range in price from $7,000 to
$25,000 per seal based on estimated shaft seal costs in the Muddy Run
Watershed, Clearfield County, Pennsylvania.
                               - 260 -

    - 261 -


         Many minerals and ores are obtained by mining.  Usually,
these minerals are associated with inorganic (metallic) sulfides, which
are broadly classified as pyrites.  Some ores that are mined for the
recovery of metals such as lead, zinc, silver, and molybdenum are
sulfides themselves.  In other instances, the pyrites may be intei—
mixed in the ore or mineral, or located adjacent to the deposit.

         In general, exposure of pyrites and other inorganic sulfides
to the atmosphere results in their oxidation to a sulfate salt.  The
dissolution of these salts into ground or surface waters results in a
varying degradation of water quality. These sulfate compounds usu-
ally impart acidity to the water, and as the drainage becomes more
acid, most of the associated elements and compounds become
more soluble.  The most common ions associated with mine drainage
are iron (ferrous and ferric forms), aluminum, calcium, magnesium,
manganese, copper, zinc, lead, cadmium, nickel, arsenic, silver,
chloride, fluoride, sulfate,  phosphate, radioactive materials and
others.  The presence and concentrations of any Ion In mine drainage
will vary with the mineral or ore being mined, the geographical lo-
cation, the hydrological season, etc. This variation can even be
significant within different areas of the same mine.

         Mine drainage can be treated by combinations of various chem-
ical and physical processes  to produce a water of  almost any desired
quality.  Most often, mine drainage  is treated to remove those chem-
ical compounds  considered to be pollutants to the aquatic life or other
uses of the receiving stream.  In some locations,  mine drainage Is
being treated for use as public and industrial water supplies where it
is the only source of water available .
                               - 263 -


        - 265 -


                       13.1  METHOD DISCUSSION
        When mine drainage is acid, the acidity can be neutralized by
addition of an alkaline material. By properly selecting the alkaline
agent, many metals (cations) can be  removed during neutralization as
insoluble hydroxides.  Anions such as phosphates, fluorides and
sulfates can also be removed by calcium alkalis  using this insolubility

                             Alkali  Selection

        Several alkaline materials are available for neutralizing acid
mine  drainage.  These include lime, hydrated lime, limestone, caustic
soda, soda ash and others.  The choice of alkali may depend on its cost,
reactivity, availability, volume of sludge produced, ease of handling
and desired effluent quality.

        Recent studies have optimized analytical, bench-scale, and
pilot plant methods for evaluation of  alkalis and  treatment processes.
A cost comparison of several alkalis is presented  in Table 13.1-1 .

                             TABLE 13.1-1

                                    Basicitya   Costb    $/Tonne of
                                     Factor    $/Afonne     Basicity

Quick Lime
   (Calcium Oxide)                   1.786     $25.35       $14.19

Hydrated Lime
   (Calcium Hydroxide)              1.351      27.56         20.40

Limestone, Rock
   (Calcium Carbonate)              1.000       8.82         8.82
                               - 267 -

                                   Basicltya    Cost      $/Tonne of
                                     Factor    $/Tonne     Basicity

Limestone, Dust
   (Calcium Carbonate)               1.000      $11.02      $11.02

   (Calcium-Magnesium Carbonate)   0.543       25.90°      47.70°

Mag ne site
   (Magnesium Carbonate)            1.186       27.56       23.24

Caustic Soda
   (Sodium Hydroxide, 50%)          1 .250       83.77       67.02

Soda Ash
   (Sodium Carbonate, 50%)          0.943       39.68       42.08

Ammonium Hydroxide                1.429       71.65       50.14

        a.  Grams of calcium carbonate (CaCO~) equivalent
            per gram of alkaline agent.

        b.  F.O.B. costs to Pittsburgh, Pennsylvania, June,

        c.  Estimated costs, material as such is not generally
The available alkalinity in each material is defined by its calcium car-
bonate equivalent.  This can be used with the material's cost to calcu-
late an equivalent cost per tonne of calcium carbonate content. If a
material is not 100% efficient;  i.e., if it must be added in excess, then
its cost will be proportionately higher.

         Practically any alkaline material can be used to remove or
neutralize acidity.  Since most mine drainage treatment facilities
                               - 268 -

must treat large volumes of water, cost and effluent quality are usual-
ly the most important factors. As a  result, lime, hydrated lime and
limestone are the  more commonly used alkalis.

         The concentrations of heavy metals in aqueous solution can
usually be  reduced by precipitation as insoluble hydroxides. The pH at
which this  precipitation occurs is different for each metal.  Typical pH
values from one study are presented  in Figure 13.1-1.  Precipitation
as the  insoluble hydroxides  will generally remove these metals to con-
centrations of one mg/1 or less.  In the case of amphoteric metals, such
as zinc and aluminum, the metal will resolubilize if the solution be-
comes too  alkaline.  This may present a problem if more than one metal
is to be removed from solution.













SJ2 Ft3 A? P£2 C^2 2? Nf2 Ft2 Cf M?
                   OF  METAL  IONS  AS HYDROXIDES
                              Figure 13.1-I
                               - 269 -

                            Iron Removal

         The choice of neutralizing agent becomes important if ferrous
iron is present in the drainage.  Ferrous iron does not reach minimum
insolubility as the hydroxide,  unless the pH is above  9.5.  Ferric iron,
however, can be essentially removed as a hydroxide  at a pH of about
5.0.  Ferrous iron can be oxidized to the ferric form, but this too is
pH dependent, and the solution pH should be 7.0 or higher for  the re-
action to proceed quickly. Aeration is  required to provide an  excess  of
oxygen in the system for this oxidation  reaction.

         Alkaline materials such as lime, soda ash and caustic soda
can easily neutralize the acidity and raise the pH to a level where fer-
rous iron oxidation can be accomplished. When using limestone, car-
bonic acid is formed in the neutralization reaction, and this suppresses
the  solution pH to a point  where the ferrous iron oxidation is slow.
Vigorous aeration can be  used to drive  off the carbon dioxide,  but this
does not greatly improve  the process.  Overall, limestone is  impracti-
cal  for use in neutralizing mine drainage containing substantial concen-
trations  of ferrous iron.

         When ferrous iron  is present in mine drainage that is alkaline,
the  oxidation and removal as ferric hydroxide will occur naturally.
Large settling ponds with detentions of  several days  have been used
for  this purpose.

         The processes and methods available for the oxidation and
 removal of iron from mine drainage are discussed in Section 22.0
 of this manual.
          11,  12, 75, 93, 131, 144, 190
                               - 270 -

      - 271 -


                       14.1  METHOD DISCUSSION
         Limestone is a general term applied to a family of rocks com-
posed primarily of calcium carbonate or combinations of calcium and
magnesium carbonates. Since  limestone is an inexpensive material,
it is often considered for use in neutralizing acidic wastewaters.
Early investigations employing  limestone for neutralization of acid
mine drainage, found that the limestone surface quickly coated with
iron, rendering it unreactive.  Recent studies into the problems as-
sociated with mine drainage treatment have developed techniques for
optimum utilization of limestone.

         For neutralizing acidic wastes, limestones can be rated by
their calcium carbonate or calcium oxide equivalent content.  It has
been found that limestones containing appreciable amounts of  dolomite
(magnesium carbonate) react very slowly. The neutralizing efficiency
of limestone increases with higher calcium oxide and lower magnesium
oxide content.  Calcites, therefore,  are more effective than either colo-
mites °r magnesites. Size of the limestone particle also has an ef-
fect on neutralization, with the  smaller sized particles reacting at a
faster rate.

         Overall efficiency of any system using limestone to neutralize
acid mine drainage depends  primarily on the concentration and  ionic
form of any iron present.  As mine drainage is formed, iron  is in the
ferrous form and cannot be completely removed as a hydroxide  pre-
cipitate unless  the pH is greater than 9.5. Ferrous iron can  be oxi-
dized to the ferric form, which is more insoluble, and will precipitate
as the hydroxide in a 5.5 to 7.0 pH range. Oxidation of ferrous iron is
greatly dependent  on the pH  of the solution. The oxidation is  slow at pH's
between 4.0 and 6.0, moderate in the 6.0 to 8.0 range,  and proceeds
rapidly at the higher pH's.

         If the drainage contains iron in the ferrous form, it will be
difficult to treat with limestone.  Limestone will effectively neutralize
mineral acidity, but forms carbonic acid in the process. This limits
the solution's pH to about 6.5.  At this point, ferrous iron is  soluble
                                - 273 -

and does not rapidly oxidize, so little is removed.  Aeration of the
drainage will expel carbon dioxide and increase oxidation.  As the
oxidation  reaction occurs, additional acid is formed and the; pH of the
drainage will decrease. As a result, additional amounts of limestone
must be added to accomplish complete neutralization and iron removal.
Therefore, limestone treatment of mine drainage containing high con-
centrations of ferrous iron is impractical.

        Limestone can be used effectively to treat mine drainage that
contains mostly ferric iron.  One problem is that the limestone will
coat with  a film of calcium and  iron sulfate which will slow, and  even-
tually stop, the  reaction.  If the iron and acidity concentrations are low,
stationary limestone beds or pulverized limestone can be used.  For
acid drainages containing significant amounts of iron, a means to keep
the limestone free of this coating is necessary. Processes using agi-
tation for pulverized limestone and rotating tumblers for crushed lime-
stone rock are discussed in the next two sections of this manual.

        Limestone has several advantages over other alkaline agents.
The sludge produced in the treatment process has been found to be more
dense in that it settles more rapidly and occupies a smaller volume.
The limestone feed rate is not as sensitive as with other alkalis; i.e.,
an overfeed of limestone will not drastically affect the pH of the treated
water.  Also, limestone is easier to handle than other alkaline materials,

        Disadvantages in using limestone center around its slow re-
activity.  Since  the reaction rates are slower,  longer detention times
are required in the treatment units.  As a result, excessive limestone
is used  and the cost for neutralization is usually more than when  using
lime.  Limestone gives poor results when treating acid mine drainage
containing ferrous iron in concentrations above 100 mg/l.

        Very few actual operating systems have  been installed that use
limestone for the treatment of acid mine drainage.  As a result,  the
only construction and operating costs that are available, are estimates
from studies to  be discussed.   The estimated construction costs from
one study are in line with those presented for lime neutralization.

        Actual  and projected operating costs have been found to  vary
                               - 274 -

greatly.  The quality of the drainage,  presence of ferrous iron,  effi-
ciency of the mixing and aeration systems, and delivered cost of lime-
stone all influence the chemical operating costs.  On an equalized
limestone price of $6.60 per tonne ($6.00 per ton),  limestone costs
have been reported to vary from 1 .0 to 2.6 cents per thousand cubic
meters treated per mg/l of acidity (4-10  cents per million gallons
treated per mg/l of acidity) for drainages containing mostly ferric
iron, and from 1 .32 to 2.11 cents (5-8 cents) for drainages  containing
mostly ferrous iron. Generally, ferric iron waters are more easily
treated than those containing ferrous iron and the chemical costs will
be lower.
         11, 12, 18, 25, 74, 75,  77,  81, 89, 114, 144
                               - 275 -

        Two studies have been completed on the use of pulverized lime-
stone for treating acid mine drainage.  In both cases, the work was per-
formed in pilot sized units and full scale  plants have never been con-
structed.  The purpose of these studies was to determine if limestone
would effectively treat acid mine drainage, containing ferrous iron in
one study and  ferric in the other,  while producing an acceptable ef-
fluent.  Costs were then determined for comparison with other pro-
cesses .  Both processes are essentially the same and each is discussed

                      FWQA Norton Field Site Study

        The Federal Water Quality Administration studied the treat-
ment of acid mine drainage at their Norton, West Virginia Mine Drain-
age Field Site which had an average quality of:

                     pH            =3.0
                    Acidity (hot)   =  1200 mg/1
                     Iron, total     =  1OO mg/1
                     Iron, Ferrous -  25 mg/1

        The mine drainage was introduced into a reactor vessel equip-
ped with a flash mixer.  Limestone was used both  in a dry form (rock
dust < 50 mesh), and as a slurry.  The treated drainage  was then set-
tled for about four hours.  Figure 14 .2-1 is a flow sheet  of this pilot
         There was essentially no difference  in overall results by using
limestone in a slurry rather than as dry rock dust. Aeration of the
                                - 276 -

solution following limestone addition had no overall effect.  However,
using a slurry and aerating the neutralized drainage both have a signi-
ficant effect on the reaction or detention times required. This should
be taken into consideration in the design of any treatment facility. With-
out aeration, the pH of the mine drainage treated with limestone had
not stabilized after 4 days.

         Limestone treatment produces a dense, rapidly settling, sludge.
The sludge was found to contain a considerable amount of unused lime-
stone, which is a waste of the alkalinity purchased.  It was recommend-
ed that recirculatlon of the sludge to the reactor be provided  In a full
size facility In order to reduce the  amount of limestone needed for

         From this study  it was concluded that limestone can effectively
produce an effluent with a pH of 6.5 and an iron concentration of about
2.0 mg/l.  Sulfates were reduced to the calcium sulfate solubility,
which is about 1000 mg/l  as SO4.
                    SCHEMATIC  FLOW DIAGRAM
                    FWQA PILOT  PLANT  SYSTEM
                        NORTON  FIELD  SITE
                             Figure I4.2-I
                               - 277 -

                   BCR Limestone Treatment Process

        Bituminous Coal Research, Inc.  conducted an extensive pilot
scale study on the treatment of acid mine  drainage  containing mostly
ferrous iron with pulverized limestone.  Their studies were performed
on acid mine drainage having an average quality of:
                   Acidity, mg/l (CaCOg)
                   Ferrous iron, mg/l
                   Ferric  iron, mg/l
                   Sulfate, mg/l
4.6 - 5.6
        Experimental work was conducted in a pilot facility consisting
of the units shown on the flowsheet, Figure 14.2-2.  From this,  it was
recommended that the  individual units be designed to provide minimum
detentions of 12 hours  in the Equalization and Settling  basins, and one
hour each in the Reactor and Aeration units.
                  SLUD4E- BE-CIBCULATIOKI
                           FLOW  DIAGRAM
                          BCR   LIMESTONE
                        TREATMENT PROCESS
                             Figure  14.2-2
                               - 278 -

         The study concluded that acid mine drainage containing ferrous
iron in concentrations up to 100 mg/l could be treated with pulverized
limestone to produce an acceptable effluent.  Limestone having a high
calcium  content and pulverized to a size of 200 mesh and smaller is
most ideal and should be pre-mixed for slurry feed. Sludge recircula-
tion produced a more dense sludge and nearly complete use of the avail-
able alkalinity.   Vigorous aeration was required to drive off the carbon
dioxide formed in the neutralization reaction and to oxidize the ferrous
iron. Detention times in the aeration unit are excessively large when
compared to treatment with other alkalis.
         This study presented construction cost estimates for facilities
to treat flows of 378.5, 3785, 15140, and 26,495  cu.m./d(0.1, 1.0,
4.0 and 7.0 mgd).  These cost estimates assumed that land was avail-
able with level topography so a gravity flow system could be developed.
The aeration and settling basins would  be of earthen construction and
clay is on site for  lining these units.  A separate dewatering basin would
be provided for the sludge removed from the settling basins.  Duplicate
units are not provided, but the system  is well  equipped and  is automated
as much as practical.

         The construction and operational cost estimates are summarized
in Tables 14.2-1 and 14.2-2. The construction costs are in line with
those presented for the conventional lime neutralization process discussed
in Section 15.2. These costs estimates were made in June 1971, when
the ENR construction cost Index was about 1575.
         12, 55, 75
                               - 279 -

                          TABLE 14.2-1
1.  Structures
2.  Control Building
3.  Equipment
4.  Piping
5.  Electrical
6.  Control Equipment
7.  Other
8.  Contingencies
9.  Engineering
    Total Capital Costs
    Cost/Unit Capacity, $/m3
1 .  Structures
2.  Control Building
3.  Equipment
4.  Piping
5.  Electrical
6.  Control Equipment
7.  Other
8.  Contingencies
9.  Engineering
    Total Capital Costs
    Cost/Unit Capacity,
 378.5 m3/day*
  (0.1 MGD)

   $ 29,610
   $ 344.19

15,140 ms/day**
   (4.0 MGD)
 3785 m3/day*
  (1.0 MGD)


   $  93.00

26,495 m3/day*
   (7.0 MGD)
$327, 9OO
$ 43.52
$ 51.38
                              - 280 -

*   Theoretical design quality of coal mine drainage:
    Acidity as CaCO3 = 1000 mg/l,  Ferrous Iron = 500 mg/l, and
    Ferric Iron = 0 mg/l

**  Actual Coal Mine Drainage Tested with Average Quality of:
    Acidity as CaCOg =190 mg/l, Ferrous Iron = 90 mg/l, Ferric
    I ron = 0 mg/l
                              - 281 -

                           TABLE 14.2-2
Coagulant Aid
Sludge Disposal
Direct Operating Cost
Capital Cost Amortized***
Total Operating Cost
Coagulant Aid
Sludge Disposal
Direct Operating Cost
Capital Cost Amortized***
Total Operating Cost
(0 . 1 mgd)
(4.0 mgd)
(1 .0 mgd)
(7.0 mgd)
1 .32
                              - 282 -

*   Theoretical design quality of coal mine drainage:
    Acidity as CaCO3 = 1000 mg/l, Ferrous Iron = 500 mg/l, and
    Ferric Iron = 0 mg/l

**  Actual Coal Mine Drainage Tested with Average Quality of:
    Acidity as CaCOg =190 mg/l, Ferrous Iron = 90 mg/l, Ferric
    Iron =0 mg/l

*** Capital costs are amortized for 20 years at 6% interest. Con-
    tingencies are 1% of the estimated construction costs.
                              - 283 -

         Crushed limestone rock has been successfully used to treat
acid mine drainage discharged from two Pennsylvania coal mines.  Ro-
tating drums partially filled with the  rock are used to prevent the coat-
ing of calcium and iron sulfates on the limestone surfaces.  In both
cases, the iron present was mostly in the ferric form.
         The U.S. Bureau of Mines began to study the neutralization
of acid mine drainage in 1966.   From this, a process was developed
and an operating facility installed in 1967-68 that treats a flow of about
18.93 1/s (300 gpm) having a quality of:

                   pH                        2.8
                   Acidity, mg/1  (CaCO3)    1700
                   Ferrous iron,  mg/1         36
                   Total iron,  mg/l           360
                   Sulfate, mg/1             3900

         The treatment facilities consist of an 11,355 cubic rneter (3.0
million gallon) holding basin; a 0.914 meter (3'-0") diameter by 7.32
meter (24'-0") long tube mill driven by an 11 .2 kW  (15 Hp) variable-
speed motor; 227 cubic meter (60,000 gallon) earthen aeration basin
equipped with a surface aerator and air sparging system, and a  132.5
cubic meter (35,000 gallon) settling basin.  A flowsheet for this pro-
cess is shown on Figure 14.3-1.

         The tube milt was used to produce a limestone slurry.  Tests
were conducted to optimize the limestone size, rotation speed and water
                               - 284 -

flow through the tube mill.  It was concluded that 0.39 cm x 1.18 cm
(1" x 3") limestone rocks, and a small flow of water at a high rotation
speed of 2.62 rad/s (25 rpm) produced high dissolution rates of lime-
stone into  the slurry.  The slurry was then mixed with the mine drain-
age in SL long trough before entering an aeration basin for oxidation of
the ferrous iron.  This was followed by a settling basin for removal of
the precipitated solids.  The facility produced a treated water with a
pH of about 7.0, and a total iron content of less than 7 mg/1.
                                       LIMESTONE FEED
                                                        MINE DRAINAGE
                                   FOR LIMESTONE
                              BLOWER FOR
                              AIR SPARGER
                                    fTT~> iTy. TT v-x -T
                                  SEDIME NTAT ION  POND ~
                                                  DISCHARGE" TO STREAM
                          FLOW DIAGRAM
                  AFTER U.S. BUREAU OF  MINES (114)
                            Figure  14.3-1
                                - 285 -

         The limestone cost in treating water by this facility was $0.03
per thousand cubic meters ($0.115 per million gallons) treated per mg/l
of acidity, based on a delivered cost of $6.60 per tonne ($6.00 per ton).
Construction cost estimates for treating  a wide range of flows and quality
were presented by the Bureau in a subsequent study; however, these
estimates seem out of line when compared to costs reported elsewhere.
For  this reason,  they are not presented  here.
         25, 114
                               - 286 -

        - 287 -


                      15.1  METHOD DISCUSSION
         Lime has been used for many years by industry to neutralize
acid waste waters and remove heavy metals as insoluble hydroxides.
Lime is available in a variety of forms,  but two are the most useful.
Quicklime is produced by calcining (burning) limestone at high tempera-
ture.  It is composed almost entirely of calcium oxide (88%) and has to
be slaked into a slurry of hydrated lime for use. The slaking process
produces considerable heat and must be carefully controlled to obtain
maximum reactivity.

         Hydrated lime is a  dry powder obtained by treating quicklime
with water.  It costs about the same as quicklime and is ready to use;
i.e., it can be easily mixed  with water to form a solution or slurry.
This form of lime is most often used for the neutralization  of acidic
wastes, including acid mine drainage.

         Lime is readily available, relatively simple to use, and consist-
ently neutralizes the acidity and removes the iron and other metals pre-
sent in  mine drainage  at a reasonable, if not the least cost.  For these
reasons,  lime is used in most of the estimated 300 plants now in exist-
ency that treat mine drainage.  There  are disadvantages associated with
using lime; these include, an increase in the hardness of the treated
water,  problems with  scale  (gypsum) formation on plant equipment, the
possibility of over-treatment resulting in high discharge pH's, and the
difficulties in dewatering or  disposal of the large volumes of sludge that
are produced.
         9, 68
                               - 289 -

         In the lime neutralization process, there are four basic steps
that are commonly employed to effectively treat mine drainage.  First
the drainage is neutralized with lime, usually in a slurry form, by vigor-
ous mixing for one to two minutes.  Neutralization is immediate,  and the
drainage is  then aerated for a  15 to 30 minute period to oxidize ferrous
iron to the ferric form.  Following this,  the drainage is settled in either
mechanical  clarifiers, or  large earthen settling basins  for removal of the
solids formed by the process.   The treated water is discharged and the
final step involves disposal of  the sludge produced in the clarification
operation.  General methods available for sludge disposal are  discussed
in Section 16.0.
         In the conventional lime neutralization process, each of these
four operations follows in normal sequence, i.e., neutralization (mixing),
aeration, settling,  and sludge disposal.  Flow is once-through and grav-
ity systems are usually employed.  A flowsheet for the typical system
is shown on Figure 15.2-1 .

         To simplify the controls  needed in the system and to minimize
operator attendance,  a constant flow with only small variations in quality
is desirable.  To accomplish this, the mine drainage is collected in
large holding or equalization basins.  From these,  it either flows by
gravity or is pumped to the treatment facilities.  Since most mines are
in rural areas, both the holding and settling basins  are usually surface
impoundments  of earthen construction.
                               - 290 -

                               SLURRY SYSTEM
                   SLUDGE REQUIRING
                           Figure 15.2-1
         Many factors affect the costs associated with the treatment of
mine drainage.  Construction costs are affected by the capacity of the
plant, the availability of land with acceptable topography, site acces-
sibility, availability of electricity, and method selected for sludge dis-
posal.   While many plants use this conventional process, actual cost
data is  not readily available.  Construction costs from documented case
histories have been used to develop the  curve presented  in Figure 15.2-2,
                               - 291 -

                   Smaller  Capacity Plant

          Figure  15.2-2

            - 292 -

         Operating costs vary significantly, and are affected by the
drainage quality (chemical requirements), pumping needs,  chemical and
power costs, labor needs, and sludge disposal.  The costs  for sludge
disposal can be as much as 50% of the total operating cost,  and the
methods available for this are discussed in Section 16.0.  Actual and
estimated operating  costs for several plants are tabulated in Tables
15.2-1 and 15.2-2.  Operating costs vary from 3 to 12 cents per thou-
sand cubic meters (11 to 45 cents per million gallons) treated per  mg/1
of acidity, but are generally in the range of 4 to 7 (15 to 27) cents.
         9, 45,  46, 64, 68, 82, 98, 101, 163
                              - 293 -

                           TABLE 15.2-1
                   SUMMARY OF CAPITAL COSTS
 1 .  Bethlehem Mines Co.
    No. 58-A
 2.  Bethlehem Mines Co.
    No. 58-B
 3.  Young & Son
 4.  Morea Strip
 5.  Blue Coal Corp.
    Loomis  No.  4
 6.  Duquesne Light Co.
    Warwick No. 3
 7.  West Virginia Univer-
    sity School of Mines
    Mine No.  1
 8.  Duquesne Light Co.
    Warwick No. 2
 9.  Commonwealth of Pa.
    Slippery Rock Creek
    Treatment Plant
    Rausch Creek Mine
    Drainage Plant

10.  Mountaineer Coal Co.
                                                CAPITAL COSTS
                            Design     Total
                           Flow Rate   Acidity
                           M3/Day     mg/l
908    4,080   $  347,200  $382.38
 1,136     8,150
1 1 , 446
  423,200   372.53

  229,900   337.59

  657,400    43.42

1,094,000    50.18

  229,700   101.14
  750,000    65.53
                1,747,380    46.17
  120,000    44.04
                              - 294 -

                          TABLE 15.2-2
                                               OPERATING COST
 1.  Bethlehem Mines Co,
    No. 58-A
 2.  Bethlehem Mines Co,
    No. 58-B
 3.  Young & Son
 4.  Morea Strip

Blue Coal Corp.
Loomis No.  4
Duquesne Light Co.
Warwick No. 3
West Virginia Univei—
sity School of Mines
Mine No.  1
Duquesne Light Co.
Warwick No. 2
Commonwealth of Pa.
Slippery Rock Creek
Treatment Plant
Rausch Creek Mine
Drainage Plant
Mountaineer Coal Co.
rlow Rate
2 1 , 802
1 1 , 446
$ 95,250
mg/1 acidi


                              - 295 -

         The Bethlehem Steel Corporation reported development of the
High-Density Sludge Process in 1970.  This process uses lime for
neutralization and produces a very dense sludge of much less volume
than the conventional lime neutralization process (Section 15.2).  The
process is based on a high sludge recirculation rate within the system
with a 20 to 30:1  ratio of solids recirculated to solids removed  consid-
ered optimum.  The sludge is returned to a reactor vessel where the
lime slurry is added.  This point of alkali  introduction to the system is
important.  The slurry is then mixed with  the acid mine drainage in a
neutralization reactor where aeration is provided for oxidation  of fer-
rous iron.   Removal of the systems' solids is accomplished  in a mech-
anical thickener.  The process flow sheet is shown in Figure 15.3-1.
         The higher sludge solids was found to vary with the ferrous to
ferric iron ratio in the raw acid mine drainage.  Sludge densities of up
to 50% solids were obtained as the ferrous iron content approached
100%.  On a high ferric iron drainage, a sludge density approaching
20% solids was obtained.  These  can be compared to sludge densities
of 2 to 6% that are normally produced in the conventional limes neutral-
ization process.
         Cost information for the High-Density Sludge Process is not
                               - 296 -

available.  Capital costs can be expected to be about the same, or slight-
ly higher than for treatment by conventional means.  A demonstration
plant constructed in 1967 treated  a maximum flow of 50.5 1/sec (800
GPM).  The total cost of the plant including modifications and changes
was $350,000.   A substantial cost savings for sludge disposal will be
realized by using this system.





                                           WASTE SLUDGE
                                            1%  SOLIDS




1 	 1
                                                           . WASTE SLUDGE
                                                           15-40% SOLIDS
                             Figure 15.3-1
         See Section 15.2 on Lime Neutralization.
                               - 297 -

         The Environmental Protection Agency has investigated a two-
stage neutralization process using limestone and lime at their Mine
Drainage Field Site at Norton, West Virginia.  It had been found that
limestone is highly reactive in neutralization tests at low pH's, but be-
comes relatively inefficient at pH's  above 6.0 due to inherent problems
with the formation of carbonic acid and oxidation of ferrous iron.
         Limestone has advantages over lime in raw material cost and
it produces a more dense sludge of lesser volume.

         The study was conducted on acid mine drainage containing iron
in the ferric form.  Tests on the combination process were conducted
in a pilot-scale plant and compared to treatment by lime and limestone
separately. This study concluded that the best results are obtained by
using limestone to neutralize the drainage to a pH of 4.0,  and then us-
ing  lime to achieve any desired final pH.  Reaction times of 20 to 30
minutes are required for efficient utilization of limestone and 10 to 15
minutes for lime. This combination process produced a sludge volume
one-half that produced when using lime alone, with a solids content
five times more dense.  This volume of sludge, however, was slightly
more than that produced by using limestone alone. All three materials
produced a treated water of similar quality.
                               - 298 -

         The investigators of this combination process feel that it has
a "tremendous economic potential for cost reductions  in acid mine
drainage treatment." Additional equipment for the combination process
consists of bulk storage, feeding, slurry mixing and reactor (large mix-
ing vessel) facilities.  These should not increase the capital cost of the
treatment plant by more than 25%.

         Operating costs of the combination process are based on lime-
stone and hydrated lime costs of $6.61  and $19.84 per tonne ($6.00 and
$18.00 per ton) respectively.  Estimated chemical  costs for neutraliza-
tion of acid mine drainage are compared to neutralization with either
lime or limestone alone in Table 15.4-1.
                           TABLE 15.4-1

                       Typical Chemical Costs
                 Cents/3.785 M3 (Cents/1000 gallons)

                        Lime    Limestone    Limestone - Lime
          Final pH       Only       Only       Cost   % Savings

       6.5              2.61        —         1.94     25.7%
       6.5               —        3.44       2.37     31.1%

       9.0  (ferric)     3.13        —         2.46     21.3%
       9.0  (ferrous)    4.43        —         3.77     14.9%
         The acid mine drainage used had an average quality of:

                    pH                    2.8
                    Acidity, as CaCos     430 mg/1
                    Iron, total             92
                              - 299 -

         This process also reflects cost savings for the treatment of
drainages containing more acidity or ferrous iron. When ferrous iron
is present, limestone is not practical to use, but a cost comparison
for lime and  the combination limestone - lime process is presented in
the preceding Table.
                               - 300 -

                  15.5 STREAM NEUTRALIZATION
         The Pennsylvania Department of Environmental Resources has
constructed an automatically operated hydrated lime neutralization sys-
tem for treatment of streams affected by acid mine drainage.  The sys-
tem is applied to streams which are mildly acid but contain very little
iron,  aluminum, manganese or other compounds that will precipitate  as
insoluble compounds.

         The system as shown in Figure 15.5-1, consists of a lime
storage bin with a variable speed feeder.  Stream flows are measured
by a float behind a weir, and flow and upstream pH both control the lime
feed rate.  Lime is introduced dry behind the weir and an electric mixer
and baffles insure rapid dissolving.
         These plants have operated with little problem and have re-
turned several streams to a quality that supports aquatic life.
        The several plants installed by Pennsylvania have capital costs
ranging from $40,000 to $54,000 and have treated flows ranging from
568 to 21,764 cubic meters a day (0.15 to 5.75 mgd).  Operating costs
have ranged from $300 to $741  a month, or  1.5 cents a cubic meter
($0.0573/1000 gallons) in periods of low flow to 0.18 cents a cubic meter
($0.0068/1000 gallons) in periods of high flow.
                               - 301 -

                                BAFFLES -
                           Figure 15.5-1
                             - 302 -

   - 303 -


                     16.1  METHOD DISCUSSION
         Neutralization of acid mine drainage with any of a variety of
alkalis,  results in production of substantial quantities of sludge contain-
ing insoluble precipitates and unreacted solids.  The sludge is usually
very voluminous, containing from one to five percent dry solids by
weight, which presents a considerable volume for disposal. Those
methods that are currently used or proposed for use in sludge disposal
are discussed herein.

         A significant  portion of the operation costs of any treatment
system will be for sludge disposal.  Cost data for disposal of these
sludges is not available.  As a guide, one study presented costs for the
disposal of sewage sludges.  These costs do not provide for sludge con-
ditioning or ultimate disposal, nor are they directly comparable to mine
drainage sludges. These are presented in Table 16.1-1 and should be
used only to compare one method to another.
                           TABLE 16.1-1
            System                   Capital & Operating Costs
                                             $/Dry Tonne

                                      Average          Range

       Lagooning                         $ 2            $ 1 -  5
       Sand Bed Drying                   —              3-20
       Vacuum Filtration                  15              8-50
       Heat Drying                        35             25 - 40
        12, 23, 74,  82
                               - 305 -

         Lagooning of wet sludge is the most commonly used method of
disposal. At times, land conditions permit construction of enormous
settling ponds.  These may have the capacity to store settled sludge
for several years or, perhaps, for the life of the mine drainage treat-
ment facility.   Usually the damming of entire valleys or use of open
cuts in strip mines are required to develop these large settling ponds.
Construction and land costs must be considered in using this method of
sludge disposal.
         93, 107
                               - 306 -

                          16.3 AIR DRYING
         Another method of sludge disposal involves use of two or more
settling basins for removal of the precipitated solids.  When a basin's
sludge storage capacity becomes filled,  it is taken out of service and
the clear water above the sludge level is drained.  The sludge is then
air dried for several weeks, depending upon weather conditions.  This
drying method reduces the sludge volume considerably and it can then
be removed for final disposal.

         A variation of this sludge disposal method is use of sludge dry-
ing lagoons separate from the settling basins.  Sludge is pumped from
a settling basin on a frequent basis into  a separate air drying lagoon
for dewatering as discussed above.
         32, 102, 120
                               - 307 -

                     16.4 DEEP MINE DISPOSAL
         Wet or dry sludge has been effectively disposed of in abandoned
sections of deep mines.  This method is applicable if the iron in the
sludge is all in the ferric form.  Since ferric iron is soluble at a pH of
less than 4.0, any drainage from the proposed section of mine to be used
must have a pH above 4.0, or it will be affected by re-dissolving iron
from the sludge.  Solids such as calcium sulfate will also dissolve in
mine water,  thus  raising the total dissolved solids.
         58, 68, 93, 126
                               - 308 -

                    16.5  POROUS DRYING BEDS
         Drying beds for dewatering the sludge produced by neutraliza-
tion are usually constructed of a 0.3 to 0.6 meter (12-24 inches) thick-
ness of a porous media such as slag, limestone, sand and gravel or
other available material.  Underdrains of perforated pipe are used to
remove water percolating through the sludge layer.  Wet sludge is
pumped onto the bed and dries  by evaporation. Covered beds can pro-
vide rapid drying within several days.  Accumulations of sludge of 0.45
meters (18 inches) have been reported.  Porous drying beds may pro-
vide a feasible sludge dewatering means in systems where the volume
produced is not excessively large.
         23, 32, 91 , 102, 194
                              - 309 -

                     16.6 VACUUM FILTRATION
         Revolving-drum vacuum filters are commonly used to dewater
various types of waste water sludges.   It has been found that sludge
produced from neutralization of mine drainage cannot be dewatered on
a cloth covered filter due to its high compressibility.  Use of a precoat
rotary filter provided better results with a diatomite precoat media.

         Actual operating experience on dewatering by vacuum filtration
is very limited and additional demonstration worked is needed.  Sludge
cakes of 30% to 45% solids have been projected.
         32, 90, 91 ,  194
                                 310 -

                        16.7  LAND DISPOSAL
         The ultimate disposal of dewatered sludge from mine drainage
treatment poses a considerable problem.  This material has poor
stability and above grade disposal should not be considered.  Many of
the constituents in the sludge are soluble in water.  A site should be
selected where contamination  of either surface or subsurface waters
can be prevented. Disposal within abandoned deep mines seems the
most satisfactory where conditions permit.  Burying the sludge in a
landfill type operation has been proposed but there are no records of
such practice.
                              - 311 -


      - 313 -


                      17.1  METHOD DISCUSSION
         Evaporation processes are commercial methods of distilling
saline or brackish waters, including mine drainage, to produce a high
quality water suitable for potable or industrial uses.  There are three
different processes in use for producing potable water by evaporation.
These include:  (1) multi-stage flash evaporation (MSF); (2) multi-
effect long tube evaporation (ME-LTV); and (3) vapor compression (VC).

         A study by the  Westinghouse Electric Corporation  concluded
that the multi-stage flash evaporation (MSF) process could be applied
to a mine drainage source to produce potable water at an economical
cost.   The MSF process is based on the fact that water boils  at lower
temperatures as it is subjected to progressively lower pressures. The
feed water is heated (93°C) and introduced into a chamber where the
pressure is reduced and causes a "flash" of some water into vapor.
The vapor rises in the chamber, condenses on tubes, and is collected
in a separator as product water. Dissolved solids remain in  the feed
water which is termed "brine." The brine flows into a second chamber
where the pressure is lower than the first, and additional vapor flashes.
This process is repeated several times.  As the brine leaves the final
chamber, it is used to heat the incoming feed water.
         Expensive alloys must be used for construction of any process
equipment that will contact acid  mine drainage to prevent corrosion
problems.  As the drainage concentrates in the process, the calcium
sulfate (gypsum) concentration increases and a potential scaling pro-
blem exists.  The brine requires a disposal method that will prevent
                              -315 -

water pollution problems.  The product water produced by this process
will contain less than 50 mg/l of total dissolved solids.  This quality is
much better than is generally needed.

         Following their studies, Westinghouse was awarded a contract
by the Commonwealth of Pennsylvania to design an MSF system to pro-
duce 18,925 cu.m./day (5.0 mgd) of potable water for the Wilkes-
Barre area.  The plant was to have been constructed in conjunction with
a public utility steam producer.  Steam was to be obtained from that
source at a cost much less than could be produced independently.

         Plans to construct the MSF plant were abandoned when it was
found that it would be necessary to produce  steam, with temporary oil-
fired boilers for the first two years, at excessive operating costs.  Also,
the Pennsylvania Department of Environmental Resources rejected the
Westinghouse plan for disposal of the brine  by storage in plastic-lined
         Capital and operating costs from the Westinghouse design for
the 18,925 cu.m./day (5 mgd) Wilkes-Barre plant are presented in
Tables 17.1-1 and 17.1-2.  The operating costs in Table 17.1-2 do
not include capital cost amortization or disposal of the brine and solid
residues.  It is believed that these capital  cost estimates are low,
which was another reason why the plans for construction of this plant
were abandoned.
         37, 105, 106, 185, 186
                                -316 -

                          TABLE 17.1-1
           18,925 M3/DAY (5.0 MGD) OF MINE DRAINAGE*
             ITEM                            ESTIMATED COST

1.  Plant Construction
        Major Equipment                          $6,509,124
        Site Development                            567,000
        Equipment Erection                          914,760
        Piping                                       655,200
        Electrical & Instruments                      654,827
        Buildings, Painting, etc.                      441,000

                           Sub-total               $9,741,911

2.  Other  Facilities

        AMD Pumping System                     $  597,996
        Cooling Tower                               432,180
        Temporary Boilers                        1,007,760
        Product Water Post-Treatment                 63,000
        Engineering                                1,023,041
        Start-up Expenses                           214,200

                           Sub-total               $3,338,177

        Estimated Total Plant Cost               $13,080,088

        *Westinghouse Electric Corporation, 1971
                               - 317 -

                           TABLE 17.1-2
          18,925 M3/DAY (5.0 MGD) OF MINE DRAINAGE  *
                                  ESTIMATED OPERATING COST
                                     WITH PURCHASED STEAM
                                    ANNUAL    CENTS/3.785 M3**
Labor, direct
Labor, indirect
Total Estimated  Operating Cost
$  505,050

                                   ESTIMATED OPERATING COST
                                WITH ON-SITE STEAM PRODUCTION

                                    ANNUAL    CENTS/3.785 M3**
Labor, direct
Labor, indirect
Total Estimated  Operating Cost

 33. O

        * Westinghouse Electric Corporation, 1971
       ** Equal to Cents/1000 gal.
                              -318  -

   -319 -


                     18.1  METHOD DISCUSSION
         Natural osmosis occurs when two solutions of different con-
centration but in a common solvent are separated by a permeable mem-
brane.  If the membrane is permeable by the solvent and not the solute,
then the solvent will flow from the dilute solution into the more concen-
trated solution until an equilibrium of equal  concentration is established.
In the reverse osmosis process, the direction of solvent flow is reversed
by the application of pressure to the  more concentrated solution.  As a
result, the concentrated solution's strength  increases  and this is termed
the solute or brine.   The solvent or permeate is the product from the

        The development of reverse osmosis membranes has been sig-
nificant during the last decade.  There are three types of reverse osmo-
sis systems commercially available; they are the hollow fiber, spiral-
wound,  tubular and membranes (Figures 18.1-1, 18.1-2, 18.1-3).  Mem-
brane construction centers around the use of cellulose acetate.
                      FLOW SCREEN
                                                 EPOXY TUBE
                     HOLLOW  FIBER  MODULE
                            Figure  I8.I-I
                               - 321 -

                                                            FEED FLOW
                       SPIRAL  WOUND   MEMBRANE
                                Figure 18.1-2
                          POROUS FIBER GLASS
                          tuees IN  SERIET—
                              Figure  18.1-3
                                  -322 -

                 18.2 REVERSE OSMOSIS PROCESS
         The reverse osmosis process has been studied for use in treat-
ing acid  mine drainage by the Federal Government. Studies were con-
ducted using  the spiral wound, tubular, and hollow fiber membranes
in 37.85  cubic meter per day (10,000 gpd) test units.  Mine drainage was
first filtered to remove suspended solids and then processed through the
test units at 600 psi operating pressures.  Brine from the units was par-
tially recycled to increase the feed water dissolved solids concentration
and increase the product water output.  The flowsheet for this system is
shown in Figure 18.2-1 .
                            Figure 18.2-I
                               - 323 -

         These studies demonstrated that the reverse osmosis process
is highly effective in removing nearly all of the dissolved solids in acid
mine drainage.  Recoveries of 80% to 90% of the feed water volumes
were obtained.

         Problems with membrane module fouling occurred from calcium
sulfate formation but this could be flushed from the units by operating
at lower pressures for a short period.  Iron fouling occurred in one test
but was prevented in later studies by lowering the pH of the feed water
to less than 3.0. Acid mine drainages containing both ferric and fei—
rous iron forms were successfully processed.  Mine drainage contain-
ing high concentrations of dissolved solids including sulfates, caused
operating problems with excess calcium sulfate formation and could not
be processed.  Biological oxidation of ferrous iron was prevented by
ultraviolet disinfection. There was no advantage to first treating the
raw water to remove the iron, acidity, and other parameters.

         Product water from the unit usually contained less than 70 mg/1
of dissolved solids.   Typical quality of the product water is given  in
Table 18.2-1.

         Water of this quality; however, is not acceptable for potable
uses due to its pH, acidity, iron and manganese content.  Further treat-
ment by chemical neutralization,  coagulation, filtration and disinfection
would produce a potable quality water.

         The brine or reject water produced when processing acid mine
drainage presents a disposal problem.  In the tests conducted, brine
volume was usually about 10% to 15% of the raw water feed.  This re-
sults in an increase of 8 to 12 times in the concentrations of the various
ions that were present in the  raw water. Methods for disposal of the
brine would include  the Neutralization Processes discussed in Section
13.0, Evaporation Ponds - Section 5.3, Deep Well  Injection - Section
5.5, and the Neutrolosis  Process - Section 18.3.
                                - 324 -

                           TABLE 18.2-1
                                Raw Water        Product Water
        Parameter**              Quality            Quality
    pH                         3.1  - 3.4           4.2 - 4.4
    Specific Conductance        1000  - 2000           17-46
    Acidity                     210  - 460            32 - 46
    Calcium                     125-260           0.4-2.2
    Magnesium                   92-170           0.3-1.4
    Iron, total                    77-110           0.4-1.2
    Iron, ferrous                 61  - 71            0.3 - 1.0
    Aluminum                    12  - 15            0.2 - 1.0
    Manganese                   14-43            0.1-0.5
    Sulfate                     660  - 1340          0.9 - 4.6

         * Synopsis of tests conducted on spiral wound, tubular,
          and hollow fiber membrane systems.

        ** All units are in mg/1, except specific conductance
          (-jj. mhos), and pH.
         Actual costs for treatment of acid mine drainage are not avail-
able.  Numerous studies and demonstration plants have been completed
by the Office of Saline Water on the desalting of brackish and saline
waters.  Cost information available from these sources can be applied
to estimating capital and operating costs for treating acid mine drain-
age.  In the tests conducted on mine drainage, product water output was
about one-third less than the output in processing sea water.  Conse-
                               - 325 -

quently,  the capital cost estimating figures presented here have been
increased 50% to compensate for this.  Capital costs will vary from 18
to 28 cents per liter per day ($0.68 to $1.05/gpd) for a plant capacity
of 3785 cubic meters per day (1.0 mgd).  Operating costs for plants of
this  size will range from 13.2 to 18.5 cents per cubic meter treated
(50 to 70 cents/1000 gals.).  When processing mine drainage,  the cost
for brine disposal and final treatment of the product water must also be
         37, 59,  76, 99, 103, 132, 133, 191, 192, 193
                                 326 -

                    18.3  NEUTROLOSIS PROCESS
         During evaluation of the reverse osmosis process in treating
acid mine drainage, methods were investigated for the economical treat-
ment of the reject water or brine.  This would amount to 10% to 15% of
the volume of raw water processed, and would contain an 8 to 12 times
increase in the concentration of the raw water's dissolved solids.  The
treatment methods considered centered around the neutralization pro-
cesses.  As a result the Neutrolosis Process was developed.

         The Neutrolosis Process consists simply of treating the brine
from the reverse osmosis unit by a conventional neutralization process
(Section 15.2), and returning the clarified treated water to the reverse
osmosis unit's feed stream.  As a result the Neutrolosis Process pro-
duces product water, and sludge.   A flow sheet for this  process is shown
on Figure 18.3-1.

         The mine  drainage treated by this neutrolosis pilot plant con-
tained iron mostly  in the ferric form.  In neutralizing the resulting
brine, the pH was raised to 4.5, at which point most of the iron and
aluminum was removed.  To  control solids formation in the reverse
osmosis unit, the pH is adjusted to less than 4.0.  Therefore,  it is an
advantage to have the treated brine water at a pH as low as possible.
When ferrous iron  is dominant in the raw mine water and the brine,  it
will be necessary to raise the pH much higher for treatment.  Conse-
quently,  additional acid will have to be added to this treated water to
maintain the pH below 4.0 in  the raw water feed stream.  Continued re-
cycle of the treated brine may cause the dissolved solids to increase
to a point where a periodic blowdown may be required.  Dissolved solids
at these levels are  not expected to  have an affect on the  operation of the
reverse osmosis unit.

         The sludge produced by the Neutrolosis Process consists most-
ly of ferric hydroxide and calcium  sulfate.   The sludge volume was about
                               -327 -

1% of the raw water feed volume.
                          Figure  I8.3-I
         There is no cost information available for the construction or
operation of a system using the Neutrolosis Process.  Estimates can
be made using the data presented in Sections 15.2 and 18.1 .
         37, 59, 76, 132, 133, 192
                               - 328 -

         - 329 -


                     19.1 METHOD DISCUSSION
         Electrodialysis is a modern process that can be used to sub-
stantially reduce the dissolved solids in brackish water.  An electro-
dialysis unit consists of a number of narrow compartments separated
by closely spaced membranes.  Each compartment is bound by both
cation and anion membranes as illustrated in Figure 19.1-1 .  Positive
and negative electrodes are located at opposite ends of the unit. The
solution being processed fills the channels between the membranes and
when the electrodes are energized,  the ions in the solution migrate
through the  channels.  Cations pass through the cation membranes and
anions through the anion membranes.  As a result, channels of low
dissolved solids water and brine water are developed.
                         FEED TO   SALINE FEED










^ ! c
x x





* i <
x A

CL? OR 0?


I 	 j_
I — r
^ i <
X *

— @k
^ 1


J© ©,
\v H*






                     CONCENTRATE  PRODUCT WATER

                   ELECTRODIALYSIS STACK
                         Figure 19.1-1
                               - 331  -

         Bench scale studies have been performed on acid mine drain-
age by the Environmental Protection Agency at Norton, West Virginia.
It was found that the cation membranes quickly fouled with ferric iron.
Further tests on mine drainage that had first been treated by coagula-
tion and filtration to remove the iron were successful.

         At this time, insufficient information is available to judge the
reliability or costs of acid mine drainage treatment by electrodialysis.
Essentially no testing has been performed within the past four years
while progress has been made in the development and operation of the
process for producing water of low dissolved solids.
         37, 129, 139
                               -332 -

       20 . 0
       -333 -


                     20.1 METHOD DISCUSSION
         Ion exchange in water treatment can be defined as the revers-
ible interchange of ions between a solid medium and the aqueous solu-
tion.  To be effective, the solid ion exchange medium must contain ions
of its own, be insoluble in water,  and have a porous structure for the
free passage of the water molecules.  Within the solution and the ion-
exchange medium, a charge balance or electroneutrality must be main-
tained; i.e., the number of charges, not the number of ions, must stay
constant.  Ion exchange materials usually have a preference for multi-
valent ions, therefore, they tend to exchange their monovalent ions.
This reaction can  be reversed by increasing the concentration of mono-
valent ions.  Thus, a means exists to regenerate the ion exchange ma-
terial once its capacity to  exchange ions has been depleted.

         The most common ion exchange use is the softening of "hard"
or mineral-bearing water  for domestic or commercial purposes.  The
hardness in water is attributed to its calcium and magnesium content.
Initially, the ion exchange material is charged with monovalent cations,
usually sodium. The hard water is passed through a bed of ion exchange
material and the divalent calcium and magnesium cations are exchanged
for sodium ions.   Ion exchange materials tend to form stable compounds
through this exchange principle. When more than one type of cation is
available, the material will have an affinity for certain ones more than

         The earliest ion exchange materials were either natural or
synthetic zeolites  - mineral produced from mixtures of aluminum salts
and silicates.  In the 1930's plastic materials called resins were devel-
oped which expanded the applications of ion (cation) exchange.  In  1949,
an anion exchange resin was developed which enabled the process to be
used for total demineralization of water.  In the present day technology
of ion exchange, the resins available can be classified as strong-acid
cation, weak-acid cation,  strong-base anion, and weak-base anion types.
The affinity or selectivity for the various ions each type of resin will re-
move is given in Table 20.1-1.
                               - 335 -

                           TABLE 20.1-1
                    TYPICAL ION SELECTIVITY

Strong-Acid Cation
(Sulfonic Acid Type)
Weak-Acid Cation
(Carboxylic Acid Type)

Strong-Base Anion
(Quaternary Ammonium
Type I)

Weak-Base Anion

Ba-H- >  Ag+ >  Pb++ >  Hg++ >  Sr-H- >
Ca++ >  Cu+ >  Ni++ >  Cd++ >  Zn++ >
Fe-H- >  Mg++ >  Mn-H- >  K+ >  Na+ >   H+
 Cu++>   Ca++>  Mg++>  K+
HSO4~>  NO3~>  Br~>  CN~>
              1~>  HCO3~ > OH"
HSO3~>  NO2~>
>   F-
          Br~ >
                          >   F
         In water treatment applications, whether for softening, demin-
eralization or for specific ion removal, the different ion exchange re-
sins are generally used as follows:

         Strong-Ac id Cation Resins:

           Sodium Form - for removal of hardness cations,
           namely calcium and magnesium.
           Hydrogen (acid) Form - for removal of all cations.

         Weak-Acid Cation Resins:

           Hydrogen (acid) Form - for removal of cations asso-
           ciated with alkaline anions.  Hardness cations asso-
           ciated with bicarbonate alkalinity are removed, where-

           as cations associates with chloride or sulfate
           anions are not.

         Strong-Base Anion Resins:

           Strong Base Form - for removal of all anions, al-
           though carbonic acid is formed in total demineral-
           ization.   This can be removed physically be decai —

         Weak-Base Cation Resions:

           Weak Base Form - efficiently removes entire strong
           acid molecules, e.g., hydrochloric acid (HCl)  or
           sulfuric  acid
         Combinations of the available resins have been used in systems
for treatment of different waters for specific purposes.  The applica-
tions of these systems to the treatment of (acid) mine drainage has been
studied mainly to produce potable water where a reduction in the total
dissolved solids is required.  These systems include:  (1) the Desal
process; (2) the Sul-biSul  process;  (3) the Modified Desal process; and
(4) the Two Resin system .   Each of these systems has been studied in
pilot sized laboratory units, and three have been evaluated in the field
in larger capacity systems.  From these investigations it has been con-
cluded that ion exchange processes can be used to demineralize mine
drainage and produce water with a quality acceptable for potable use.
         26, 52, 103, 156, 158, 159, 160
                               - 337 -

                    20.2  SUL-BISUL PROCESS
         The Sul-biSul Process was developed by the Nalco Chemical
Company but is now assigned to the Dow Chemical Company.  The pro-
cess employs a two or three bed system. Cations are removed by a
strong-acid resin in the hydrogen form, or by a combination of weak-
acid and strong-acid resins. A strong-base anion resin operates in the
sulfate to bisulfate cycle and removes both sulfate and hydrogen (acid)
ions during the exchange reaction.  Following this, the effluent water is
decarbonated to remove carbon  dioxide formed in the process.  A flow
diagram for the Sul-biSul Process when used in  a potable water pro-
cess is  shown in Figure 20.2-1 .  Filtration of the Sul-biSul Process
effluent is provided because of State Health Regulations.

ID 2 To





— -*
* 4



                                       TREATED WATER
                                        TO STREAM
                              Figure  20.2-I
                               - 338 -

         Regeneration of the cation exchange bed is accomplished with
either hydrocholoric or sulfuric acid.  The anion bed regeneration pro-
cess is novel; the bisulfate anions are converted back to the sulfate form
by the feed water.  The addition of lime slurry to the regenerant will
speed this part of the process.
         The Sul-biSul Process can be used to demineralize brackish
water containing predominantly sulfate anions. This process will be
used to treat mine drainage to produce potable water.  The process can
be applied to waters with a dissolved solids content of up to 3000 mg/l.
The raw water should have an alkalinity content of about 10 per cent of
the total anion content with a sulfate to chloride ion ratio of at least ten
to one.   The process is especially suited to alkaline waters containing
calcium sulfate such  as those contaminated by mine drainage.

         Limitations to the process center around the anion exchange
resin's low exchange capacity and its inefficient method of regeneration.
The exhausted anion  resin can be regenerated by the raw water itself; <
however, this requires a considerable volume of water and takes a sign-
ificant length of time if the sulfate content is low. The addition of a cheap
alkali such  as lime is reported to improve the regeneration; however, a
recent study showed  poor results. One problem  is the  requirement for
disposal of  this large volume of regenerants.

         The Sul-biSul Process has  been demonstrated as a process
that will demineralize brackish waters containing high sulfate concen-
trations. The process is to be used  at Smith Township, Pennsylvania,
to produce a potable  water from a stream contaminated by mine drain-
age.  The typical raw and finished water quality projected for this plant
is given in Table 20.2-1 .
                                - 339 -

                            TABLE 20.2-1

                                     AVERAGE QUALITY *
        Parameter              Raw Water       Finished Water

  pH                            6.5 - 8.4             8.0
  Alkalinity, mg/1                  76               10 - 30
  Dissolved Solids,  mg/1       1500-2000            300
  Sulfates,  mg/1                400 - 1300          50 - 1OO
  Hardness, mg/1                 1600              < 150
  Chlorides, mg/1                  16                  2
         Cost data for the Sul-biSul Process is limited to the few studies
and one plant that has been constructed.  The Smith Township,  Pennsyl-
vania plant was recently constructed with a capacity to treat 1 893 cubic
meters a day (0.5 mgd) at a capital cost of $828,000.  Operating costs
are not available as there are start-up problems with the continuous ion
exchange units.  Projected operating costs were estimated to be in the
range of 10 to 13 cents per cubic meter (40 to 50 cents per 1000 gallons).
         20, 26, 83, 103,  180,  195
                               - 340 -

         The Desal Process employs a three-bed system consisting of
a weak-base cation resin in the bicarbonate form, a weak-acid cation
resin in the hydrogen form, and another weak-base anion resin, but in
the free base form. In the first bed, anions are removed and replaced
with bicarbonate ions.  Cations are removed  in the second  unit and re-
placed by hydrogen ions. In the third bed, carbonic acid is removed by
hydroxide ions which converts the resin to the bicarbonate  form.  In
practice, when the system is  regenerated, the flow is reversed and the
third bed becomes the first.

         The Desal Process is ideally suited  to saline waters which are
alkaline and  contain little iron. Most metallic salts are converted into
soluble bicarbonates and do not precipitate in the resin  beds; however,
ferric  iron cannot be tolerated.  These salts  must then  be  removed by
coagulation  and sedimentation techniques following this  ion exchange
process.  Regeneration  of the beds  is very efficient.

         The Modified Desal Process is an adaption of the Desal Process
for use in treating acid mine  drainage.  In the Modified Desal Process
only the first step of the Desal Process is employed; i.e., the  use of a
weak base anion resin in the bicarbonate form.  This resin effectively
removes the sulfate anion as  well as any free mineral acidity.  The ef-
fluent water is then aerated to remove carbon dioxide gas, treated with
lime to remove the metallic salts, and filtered as is normally  required
for producing potable water.  Of interest is that the calcium and mag-
nesium are  in the bicarbonate form which enables them to  be removed
as insoluble  compounds  through the lime softening process.  A flow sheet
for the Modified Desal Process appears in Figure 20.3-1 .
                              -341 -

                           ^t\   -       —
              PHILIPSBURG, PENNSYLVANIA (24,136)
                            Figure 20.3-1
         The Desal Process has inherent problems if considered for
treating acid mine drainage.  The economics of the process lie in the
recovery of carbon dioxide for use as a regenerant.  The process also
requires alkaline waters with little iron  content.  The process has been
successfully used to produce potable water where these conditions were
met.  In general, the process is not applicable to the treatment of acid
mine drainage.

         The Modified Desal Process uses the first principle of the
Desal Process, the removal of the sulfate ion by a weak base anion res-
in in the bicarbonate form.  This resin also removes free mineral
acidity.  The presence of iron in the ferric form may present fouling
problems through the formation of insoluble precipitates in the anion
bed.  Product water quality from laboratory tests on the Modified Desal
Process have been summarized and are  presented on Table 20.3-1  .
                                - 342 -

                            TABLE 20.3-1
                     TYPICAL WATER QUALITY
                    MODIFIED DESAL PROCESS

                       Raw Mine         Weak Base          Final
 Parameter*            Drainage          Effluent            Effluent

 pH                      2-4              6-7             8-9
 Alkalinity                 0                 600             25 - 50
 Acidity, free             600                  0                0
 Iron, ferrous             180                100                0
 Iron, total                200                130              <0.1
 Calcium                  180                180             15-25
 Magnesium                30                 30             10-20
 Manganese                 8                  8              <0.05
 Aluminum                  15                  5                0
 Sulfate                  1500                100               75

         *All results expressed in mg/1, except pH.
         Some cost information is available for the Modified Desal Pro-
cess.  These are incomplete estimated costs, although the Common-
wealth of Pennsylvania has undertaken the construction of a potable
water production facility utilizing this process at Hawk Run near Philips-
burg.  This plant has had numerous start-up problems and is not in
operation.   The Hawk  Run plant was designed to treat 1893 cubic meters
a day (0.5 mgd) at a cost of $2,643,000.  Operating costs are not avail-

         A study by the Culligan International Company provided capital
cost estimates for unerected plants as follows:

             Capacity, m3/day          Equipment Costs

               378.5 (0.1 mgd)             $156,000
              1892.5 (0.5 mgd)             $323,000
              3785.0 (1.0 mgd)             $465,000
                               - 343 -

        The chemical costs for producing water by this process were
estimated at 13 cents a cubic meter (48 cents per 1000 gallons).
         20, 24,  83, 103, 127, 136
                                - 344 -

                     20.4  TWO RESIN SYSTEM
         In a study by the Culligan International Company, a standard
two resin system was investigated.  In the first step of this system,
acid mine drainage is passed through a strong-acid cation resin in the
hydrogen form for removal of metallic cations.  The water is then pas-
sed through a weak-base anion resin in the free base (hydroxide) form
for removal of the sulfate anions and the free mineral acidity.  The
demineralized water  is then processed through a standard coagulation-
filtration process for the production of potable water.
         The study cited was a laboratory investigation conducted on
synthetic acid mine drainage.  The system showed reasonable success
although there appeared to be a potential problem with ferrous iron
fouling in the cation bed. Hydrochloric acid was found to be a better
regenerant than sulfuric acid,  but its higher cost (45-60%) and problems
with the  chlorides in the spent solution discounted its  use.  The process
significantly reduced  cations and anions in the two beds, but chemical
coagulation  and filtration are required to reduce the iron and manganese
to levels acceptable for potable use.  Based  on the chemical costs pre-
sented, the  Two Resin Process appears to have higher operating costs
than either the Modified Desal  or Sul-biSul Processes.
         The study conducted by Culligan in which this process was pro-
                               -345 -

posed presented chemical costs of 17 cents per cubic meter (63 cents
per 1000 gallons).  This did not include the chemical costs  required
for treatment of the spent regenerants.  If hydrochloric acid is used to
regenerate the cation unit, the chemical costs would be about 21 cents
per cubic meter (78 cents per 1000 gallons).
         83, 156, 158,  160
                               -346  -

          - 347 -


                      21.1  METHOD DISCUSSION
         As mineralized water freezes,  relatively fresh water ice
crystals are formed, and the dissolved impurities have a tendency to
remain in solution and  concentrate.  When the ice formed in this pro-
cess is separated, washed and melted, fresh water is produced. This
freezing process can be accomplished by two techniques:  the  freeze
method; or the gas hydration method.  Applied Science Laboratories,
Inc. conducted a study  of freezing techniques in  1971  which considered
the effects of oxidation, reduction   in  ion concentrations,  rates of
freezing,  effects of  storage and other  significant parameters.  Reduc-
tions of more  than 85% of the various metal and  acid  components were
noted with little or no oxidation of ferrous iron.   A flow diagram for the
freezing process investigated in this study is presented on Figure 21.1-1
                     MOTHER LIQ.UOR
                               ACID MINE WATER
                              (6OOP.P.M.TOTAL IRON)
                                   PARTIAL FREEZING

I ...

                                  PARTIAL MELTING
                     FIRST MELT
                    PRODUCT WATER
                                    UNMELTED ICE
                                       I PARTIAL MELTING
                             SECOND MELT
                            PRODUCT WATER

                          COMEHNED PRODUCT WATER
                           60P.P.M. TOTAL IRON
                        OF ACID  MINE  DRAINAGE
                               Figure  2I.I-I
                                  - 349 -

         Considerable studies have been conducted on the purification of
brackish water by freezing.  Very little has been accomplished on the
treatment of mine drainage by this process.  A distinct energy advantage
exists with this process because freezing (heat of fusion) requires approx-
imately 1/6 of the energy required by the heat of vaporization.  The
freezing process appears to be technically feasible for mine drainage
treatment but to date the method has not been demonstrated.
        At this time,  insufficient information exists on the economics
of the freezing technique for mine drainage treatment.  In 1966 Schroeder
and Marchello estimated the costs of treating mine drainage by direct
freezing as follows:
            WATER COSTS PER 3.78 m3 (1000 GALLONS)
           m /D            MGD            Direct Freezing

             378.5            0.1                $3.10
           3,785              1.0                $1.32
          37,850              10                  $0.85
         378,500            100                  $0.68
         5, 71 , 139
                               - 350 -

    22 . 0
    -351 -


                     22.1  METHOD DISCUSSION
         Many minerals that are mined occur with or adjacent to other
minerals known as pyrites or iron sulfides. The exposure of these
iron sulfides to the atmosphere and  moisture causes them to oxidize to
an iron salt, namely ferrous sulfate.  These salts then dissolve into
ground or surface waters forming mine drainage.  If there is an over-
bundance of these salts and little alkalinity available in the water, the
mine drainage will be acid.  Iron present in the mine drainage is as
serious a pollutant as the acidity. The iron compounds coat the bottom
of streams, leaving them uninhabitable for aquatic life.

         As mine drainage is formed, iron is first present in the fer-
rous form.  This form  of iron is very soluble but will precipitate as a
hydroxide as the water  becomes alkaline.  Minimum solubility occurs
in a pH range of 9.3 to 12.0.

         As the water becomes alkaline, ferrous iron will oxidize to the
ferric form.  This oxidation is dependent on the pH of the water, and is
very slow at pH's less than 4.0, slow in the range of 4.0 to 6.0,  moderate
in the 6.0 to 8.0 range, and proceeds quickly above this point.   Ferric
iron Ls much less soluble than ferrous iron, and will precipitate as the
hydroxide at a pH of 5.0 with  minimum solubility at a pH of 8.0.

         In a mine drainage treatment system, such  as any of the chem-
ical neutralization processes,  it is most advantageous to oxidize any
ferrous iron present to the ferric form so it can be removed as an in-
soluble hydroxide at near-neutral pH's.  A number of methods are
available to accomplish this oxidation process, and these  are discussed
in the following sections .
                                - 353 -

                        22.2  AERATION METHODS
          Ferrous iron in mine drainage can be oxidized to the ferric
 form in the presence of oxygen.  This oxidation is pH dependent with
 the reaction proceedingly rapidly at pH's above 8.0.  In chemical
 neutralization systems, this pH requirement can be maintained
 through the addition of a suitable alkali.  The oxidation of iron then
 becomes dependent on the availability of oxygen.  The oxidation  of
 ferrous iron occurs through the reaction:

          4 FeSO4 + O2 + 10 H2O-»>4 Fe(OH)3 + 4 H2SO4.

In this reaction, the theoretical requirement  for oxidation is one part
of oxygen for seven parts of ferrous iron.

         Oxygen has a low solubility in water.  For the oxidation  re-
action to proceed as quickly as possible, oxygen must be intermixed
with the water.  Vigorous aeration is the simplest method to accomp-
lish this.  It has been found that the oxidation reaction can be accomp-
lished within a 15  to 30 minute period under the proper conditions of
pH and excess oxygen.
         The aeration of water to accomplish oxidation of ferrous iron
 is accomplished by either diffused or mechanical aeration equipment.
 This equipment is usually mounted  in tanks with a depth of 3.05 to 4.57
 meters (10 to 15 feet).  The efficiency of oxygen transfer  in the process
 can be calculated from many factors involved in the design of the unit.
 Efficiencies of 10% for diffused aeration, and 1 .5  kg of oxygen per kilo-
 watt-hour (2.5 Ibs. oxygen per horsepower-hour) are presented as
                                - 354 -

average design factors.  For a diffused aeration system, one kilo-
gram of ferrous iron (2.2 pounds) will require about 5.5 cubic meters
( 196 cubic feet) of air to accomplish the complete oxidation.  For
mechanical aeration, a system containing one kilogram (2.2 pounds)
per hour of ferrous iron would require a 0.11 kilowatt (0.15 horsepower)
unit to accomplish this oxidation.
         The capital costs involved in an aeration system consist of
the aeration basin, which is usually of earthen or concrete construc-
tion, and the mechanical equipment involved; e.g., blowers, diffusers,
turbine units, etc. Capital costs are available from a number of
sources, but these vary considerably.  One source published in  1967
seems to provide the best guide for estimating purposes, and  capital
costs as a function of plant capacity are presented in Figure 22.2-1 .

         Operating costs are a function of the power consumption of
the equipment and the maintenance required which should be minimal.
Operating costs will vary from 10% to 20% of the total  plant operating
         29,  57, 71, 81, 114, 143, 144, 162
                               - 355 -

SI lo1

                      CAPITAL COST ESTIMATE

                       AERATION EQUIPMENT


                       PLANT CAPACITY (29)

                            Figure 22.2-1
                           - 356 -

         The oxidation of ferrous iron to the ferrous form is an electro-
chemical reaction following established chemical and physical princi-
pals.  The Tyco Laboratories, Inc. conducted a study using this method
to oxidize ferrous iron under the acid conditions encountered in normal
field conditions.

         The oxidation studies were conducted, in a batch reactor on
synthetic acid mine drainage with a pH = 2.7  and concentrations of fei—
rous iron varying from 2 x 10~2|\/\ to 5 x "\Q~4-M in 0.02M sulfuric acid
solutions.  Carbon was selected  as the anode, and type 316 stainless
steel as  the cathode.   Ferrous iron was successfully oxidized at 95%
levels  at 0.8 Volt.

         The method was then studied for use in various reactor con-
figurations for field application.   A packed bed reactor system was de-
signed to determine capital and operating cost requirements.

         The use of electrochemical means to oxidize ferrous iron was
deemed successful and economical by the investigators. Oxidation of
 > 95% of the ferrous iron was achieved under acid conditions.  With
this  accomplished, it is  then possible to achieve final neutralization of
the acidity and precipitation of ferric iron in  the drainage by using lime-
stone in  the conventional manner.
         Modular electrical oxidation cells were used in estimating capi-
tal and operating costs for this process.  Each of these units was esti-
mated to cost $20,200 with a capacity to treat 22.7 cubic meters (6000
                               - 357 -

gallons) an hour at the 95% conversion level.  For a 25 year life at
interest rate, this amounts to a capacity cost of 0.69 cents per cubic
meter (2.7 cents per 1000 gallons) treated.

        Operating costs, including equipment depreciation, were esti
mated and found to be very comparable to conventional neutralization
processes with hydrated lime.
         57, 164
                               - 358 -

                       22.4 OZONE OXIDATION
         A study has been conducted by the Brookhaven National Labora-
tory of the U.S.  Atomic Energy Commission on the use of ozone to oxidize
ferrous iron to the ferric form.  Ozone production was considered using
electrical discharge, isotopic radiation and chemonuclear methods.  Both
on-site and central ozone production facilities were considered in pre-
paring cost estimates for comparison to other processes.  Following
oxidation of ferrous iron by this method,  limestone would be used for
final neutralization of the acidity present in acid mine drainage.
         The study concluded that ozone could be used to oxidize ferrous
iron under acidic conditions to the ferric form.  The process control is
much simpler than with present aeration methods.  The electric dis-
charge method of ozone production gave the highest costs for on-site
ozone production;  however, this method is the only one for which pro-
duction equipment is presently available.
         Cost estimates were presented for the ozone-limestone system
with comparison to a conventional treatment system using lime and forced-
air aeration to accomplish the iron oxidation.  For a 3785 cubic meter per
day (1 .0 mgd) plant,  capital costs of $350,000 for the lime-air system
and $280,000 for the  on-site electrical discharge ozone-limestone facil-
ities were presented.  Operating costs were comparable at 4.5 cents per
                                - 359 -

cubic meter (17 cents per 1000 gallons) treated.
                                - 360 -

                           V.  GLOSSARY
Abatement (Mine Drainage Usage) - The lessening of pollution effects
of mine drainage.

Aeration - The act of exposing to the action of air, such as, to mix or
charge with air.

Alkaline - Having the qualities of a base; i.e.,  a pH  above 7.0.

Alluvial - Describes earth material that has  recently (geologic time
scale) been deposited by moving water.

Angle of Repose - The angle which the sloping face of a bank of loose
earth, or gravel, or other material makes with the horizontal.

Anions - An ion that moves, or that would move, toward an  anode.
Negative ion.

Aquifer - Stratum or zone below the surface of the earth capable of pro-
ducing water as from a well.

Auger - Any drilling device in which the cuttings are mechanically and
continuously removed from borehole without the use  of fluids.

BCR - Abbreviation for Bituminous Coal Research, Inc., Monroeville,

Backfilling - The transfer of previously moved material back  into an  ex-
cavation such as a mine, ditch, or against a constructed object.

Bench - A level layer of earth or rock adjacent to a  surface mine site.

Bentonite - A clay formed from the decomposition of volcanic ash. Also
has great ability to absorb and adsorb water and to swell accordingly.

Bony - Rock that has a high carbon content - usually refers  to dark
colored coal mining waste material.
                               - 361 -

 Bulkhead Seal - See illustration in Section 12.2.

Cation - An ion that moves, or that would move, toward a. cathode.
Positive ion.

Clarifier - A device for removing suspended solids.

Clay Seal - A barrier constructed of impermeable clay that stops the
flow of water.

Cohesive Soil - A soil that when unconfined has considerable strength
when aii—dried and significant cohesion when submerged.

 Colluvial - Describes gravity deposits of loose and incoherent mater-
 ial at the foot of slopes.

Daylighting - A term to define the procedure of exposing an entire under-
ground  mined area to remove all of the mineral underlying the surface.

Deep Mine - An underground mine.

Deep Well - A deep boring used for the disposal of waste materials  to
the underground strata to avoid  contamination of higher ground waters.

Dissolved Solids - The difference between the total and suspended solids
in water.

Dredging - The removal of material normally submerged in a body of

Drift - A deep mine entry driven directly into a horizontal or near hori-
zontal mineral seam or vein when it outcrops or is exposed at the ground

ENR - Abbreviation for Engineering News Record.

Ecosystem - A total organic community in a defined area or time frame.

Effluent - Any water flowing out of the ground or from an enclosure to
the surface flow network.
                               - 362 -

 Erosion - Processes whereby solids are removed from their original
 location on the land surface by hydraulic or wind action.

 Evapo-transpiration - A collective term meaning the loss of water to
 the atmoshpere from both evaporation and transpiration by vegetation.

 Flume - An open channel or conduit on a prepared grade.

 Ground Water Table (or Level) - Upper surface of the underground zone
 of saturation.

 Grout - A fluid mixture of cement, sand (or other additives) and water
 that can be poured or pumped easily.

 Grout Curtain - Is created by inserting materials (usually cement) into
 rock units through boreholes to decrease their permeability.

 Highwall - The exposed vertical or near vertical wall associated with a
 strip or area surface mine.

 Homogeneous - Consisting throughout of identical or closely similar ma-
 terial whose proportions and properties do not vary.

 Hydraulics - That branch of science or engineering which treats of water
 or other fluid in motion.

 Hydrology - The science that relates to the water systems of the earth.

 Hydroseeding - Dissemination of seed hydraulically in a water medium.

 Impervious - Impenetrable.  Does not allow fluid   flow.

 Infiltration - Water entering the ground water system through the land

 Leaching - The solution of the soluble fraction of  a material by flowing

 MSF Process - Abbreviation for Multi-stage Flash Evaporation Process.
                                - 363 -

rng/1 - Abbreviation for milligrams per liter, which is a weight to volume
ratio commonly used in water quality analysis.  It expresses the weight
in milligrams of a substance occurring in one liter of liquid.

Mulching - The addition of materials (usually organic) to the land sur-
face to curtail  erosion or retain soil moisture.
Neutralization - The process of adding an acid or alkaline material to
waste water to adjust its pH  to a neutral position.

Open Pit Mines - Mining facilities where the ratio of overburden to min-
eral is small.

Outcrop - The surface exposure of bedrock or strata.

Overburden - Nonsalable material that overlies a mineable mineral.

Oxidation - The removal of electrons from  an ion or atom.

Permeability - The measure of the capacity for transmitting a fluid
through the substance.

pH - The negative logarithm  to the base ten of the hydrogen ion activity.
pH 7 is considered neutral.  Above 7 is basic - below 7 is acidic.

Photogrammetrics — The process of creating topographical mapping from
stereo aerial photographs.

Pollution - Environmental  degradation from man's activities.

Portal - The surface entrance to an underground mine.

Reclamation - The procedures by which a disturbed area can be reworked
to make it productive, useful or aesthetically pleasing.

Reg r ad ing - The movement of earth over a  surface or depression to
change the shape of the land  surface.

Riprap - Rough stone of various sizes placed compactly or irregularly
to prevent erosion.
                                - 364 -

Runoff - That part of precipitation that flows over the land surface from
the area upon which it falls.

Scarification - Decreasing the smoothness of the land surface.

Sediment - Solid  material settled from suspension in a liquid medium.

Sludge - The precipitant or settled material from a wastewater.

Sludge Density - A measure of the weight of solids  contained in the
sludge in relation to total weight.

Spoil Material - The waste material removed from a mine facility that
is not considered  useful product.

Stratigraphy - The science of formation, composition, sequence and
correlation of stratified rocks.

Strip Mine - A surface mine where the overburden is removed to expose
the mineable material.  Implies that there  is a large amount of over-
burden with respect to the amount of mineable material.

Subdrain - A pervious backfilled trench containing a pipe or stone for
the purpose of intercepting ground water or seepage.

Subsidence - The surface  depression over  an underground mine that has
been created by subsurface caving.

Surface Mine - A mine facility that is generally conducted from the  land
surface.  It does not have  a mineral  roof.

Suspended Solids - Sediment which is  in suspension in water but which
will physically settle out  under quiescent  conditions (as differentiated
from  dissolved material).

Tailings - Mineral refuse from a milling operation  usually deposited
from  a water medium .

Terracing - The act of creating horizontal  or near horizontal benches.
                               - 365 -

Transpiration - The normal loss of water vapor to the atmosphere from

Underdraln - See subdrain.

Watershed - Surface region or area contributing to the; supply of a
stream  or lake; drainage area, drainage basin, catchment area.

Weathering - Action of the weather elements in altering the color, tex-
ture, composition,  or form of exposed objects.
                               - 366 -

                        VI. BIBLIOGRAPHY
1. Adams,  L. M., Capp,  J. P., Gitlmore, D. W., Coal Mine Spoil
   and Refuse Bank Reclamation with Powerplant Fly-Ash (1972), 3rd
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2. Alger, G. R. and Baillod, C. R., Mine Tailings Disposal Basins
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3. Amos,  D. F., and Wright,  J. D., The Effect of Fly Ash on Soil
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8. Baillod, C. Robert, Alger, George R. ,  and Santeford, Henry S.,
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9. Baker, Michael Jr., Inc.,  Analysis of Pollution Control Costs,
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    Appalachian Regional Commission, 1666 Connecticut Avenue, N.W.,
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                               - 368 -

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25.  Calhoun, F. P., Treatment of Mine Drainage With Limestone (1968),
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26.  Calmon,  Calvin, Modern Ion Exchange Technology (April/May,
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                              - 369 -

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30.  Charmbury,  H. B., and Maneval,  D. R., The Utilization of In-
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46.  Draper, J. C., Mine Drainage Treatment Experience (1972),
                               - 371 -

     Fourth Symposium on Coal Mine Drainage Research,  Mellon In-
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47.  Driver, Charles H., Hrutfiord, Bjorn P., Spyridakis, Demetrios
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     mental Protection Agency,  Technology Series EPA-R2-73-140.
                               -372 -

55.  Ford, C. T., and Boyer, J. F., Treatment of Ferrous Acid
     Mine Drainage with Activated Carbon (1973),  Office of Research
     and Monitoring, U.  S. Environmental Protection Agency Tech-
     nology Series EPA-R2-73-150.

56.  Frawley, Margaret L., Surface Mined Areas:  Control and Recla-
     mation of Environmental Damage (1971) (a bibliography), U. S.
     Department of the Interior, Office  of Library Services, Biblio-
     graphy Series No.  37.

57.  Gaines, Lewis, et.  al., Electrochemical Oxidation of Acid Mine
     Waters (April 1972), Fourth Symposium on Coal Mine Drainage
     Research, Preprints, Pittsburgh,  Pennsylvania.

58.  Goddard, R. R., Mine Water Treatment — Frick District (1970),
     Mining Congress Journal,  56,  No.  3 (pp. 36-40).

59.  Gulf Environmental Systems Company,  Acid Mine Waste Treat-
     ment Using Reverse Osmosis (1971), U. S. Environmental Pro-
     tection Agency, Water Quality Office, Water Pollution Control Re-
     search Series 14010 DYG.

60.  Griffith, F.  E., Magnuson, M. O., Kirmball,  R. L., Demonstra-
     tion and Evaluation of Five Methods of Secondary Backfilling of
     Strip Mine Areas (1966), U. S.  Department of the Interior,
     Bureau of Mines, Report of Investigations No. 6772.

61.  Grim,  Elmore C. and Hill, Ronald D.,  Surface Mining Methods
     and Techniques  (1972), Mine Drainage Pollution Control Activities,
     National Environmental Research Center, U. S. Environmental
     Protection Agency,  Cincinnati, Ohio.

62.  Grube, Walter E., Jr., Smith,  Richard Meriwether, Singh,
     Rabinas N. , Sobek, Andrew A. , Characterization of Coal Ovei—
     burden Materials and Minerals in Advance of Surface Mining,
     College of Agriculture and Forestry, West Virginia University.

63.  Gwin, Dobson and Foreman, Incorporated, Evaluation of Pollution
     Abatement Procedures in the Moraine State Park, Butler County,
                               -373 -

     Pennsylvania (1971), U. S. Environmental Protection Agency,
     Technology Series 14010 DSC.

64.  Haines, G. F., and Kostenbader, P. D., High Density Sludge
     Process for Treating Acid Mine Drainage (1970),  3rd Symposium
     on Coal Mine Drainage Research, Pittsburgh, Pennsylvania.

65.  Halliburton Company, Duncan, Oklahoma, New Mine Sealing
     Techniques for Water Pollution Abatement (1970), Office of
     Monitoring and Research, U. S. Environmental Protection
     Agency Research Series 14010 DMO.

66.  Hardaway,  John, Mercury, Zinc, Cooper, Arsenic,  Selenium and
     Cyanide Content of Selected Waters and Sediment along White-
     wood Creek, the Belle Fourche River and the Cheyenne River of
     Western South Dakota (1973), Technical Support E3ranch, Sur-
     veillance and Analysis Division,  U. S.  Environmental Protection
     Agency Region VIII, Denver,  Colorado.

67.  Manser, Julia  Butler, Providing  a Solution (1972)., 3rd Mineral
     Waste Utilization Symposium.

68.  Heine,  W. H., and Giovannitti, E. F., Treatment of Mine Drain-
     age  by  Industry in Pennsylvania (1968), 2nd Mid-Atlantic Industrial
     Waste Conference, Philadelphia,  Pennsylvania.

69.  Heine,  W. N., and Gukert, W. E. , A New Method of Surface Coal
     Mining  in Steep Terrain (1972), Paper  presented to Research and
     Applied Technology Symposium on Mined Land Reclamation.

70.  Hill, Ronald D., Control and Prevention of Mine Drainage (1972),
     Battelle Conference.

71.  Hill, Ronald D., Mine Drainage Treatment, State of the Art and
     Research Needs, U. S. Department of  the Interior, Federal Water
     Pollution Control Administration, December 1968.

72.  Hill, Ronald D., Restoration of a Terrestial Environment - The
     Surface Mine,  U. S. Environmental Protection Agency, Mine
                               -374 -

     Drainage Pollution Control Activities.

73.  Hill, Ronald D., and Martin, John F.,  Elkins Mine Drainage Pol-
     lution Control Demonstration Project — An Update (1972), 4th
     Symposium on Coal Mine Drainage Research, Mellon Institute,
     Pittsburgh, Pennsylvania.

74.  Hill, Ronald D., and Wilmoth, Roger,  Limestone Treatment of
     Acid Mine Drainage (1970), U. S. Environmental Protection Agency
     Publication 1401O.

75.  Hill, R. D., and Wilmoth, R. C.,  Neutralization of High Ferric
     Iron Acid Mine Drainage (1970),  Federal Water Quality Admini-
     stration Research Series 14010 ETV.

76.  Hill, R. D., Wilmoth, R. C. and Scott, R. B.,  Neutrolosis
     Treatment of Acid Mine Drainage,  Paper Presented at the 26th
     Annual Purdue Industrial Waste Conference, Lafayette, Indiana,
     May 4-6, 1971.

77.  Hoak, R. D., Lewis, O. J.,  and Hodge, W. W., Treatment of
     Spent Pickle Liquors with Limestone and Lime (1945),  Industrial
     Engineering and Chemistry,  Vol. 37, No. 6.

78.  Hodder, Richard L., Surface Mined Land Reclamation  Research
     in Eastern Montana (1973), Research and Applied Technology
     Symposium on Mined-Land Reclamation.

79.  Hodder, R. L., Sindelar, B. W. ,  Buchholz, J., and Ryerson,
     D.  E., Coal Mine Land Reclamation Research Progress Report
     (1972), Montana Agricultural Experiment Station.

80.  Hodder, R. L., Surface Mined Land Reclamation Research in
     Eastern Montana (1973), Paper presented to Research and Applied
     Technology Symposium on Mined Land  Reclamation.

81.  Holland, C. T.,  Berkshire,  R.  C., and Golden, D. F., An Ex-
     perimental Investigation of the Treatment of Acid Mine Water
     Containing High Concentrations of Ferrous Iron  with Limestone
                              - 375 -

     (1970), 3rd Symposium on Coal Mine Drainage Research,  Mellon
     Institute, Pittsburgh,  Pennsylvania.

82.  Holland, C. T., Corsaro, J. L., and Ladish, D. J.,  Fractors in
     the Design of an Acid Mine Drainage Treatment Plant (1968),  2nd
     Symposium on Coal Mine Drainage Research, Mellon Institute,
     Pittsburgh, Pennsylvania.

83.  Holmes, J. and Kreusch, E., Acid Mine Drainage Treatment by
     Ion Exchange  (November 1972),  U. S. Environmental Protection
     Agency, Environmental Protection Technology Series  EPA-R2-
     72-056, Washington, D. C.

84.  Hopkins, Thomas C., Western Maryland Mine Drainage; Survey,
     Maryland Department of Water Resources, Water Quality Division.

85.  H. R. B.-Singer Inc.,  Science Park, State College,  Pennsylvania,
     Detection of Abandoned Underground Coal Mines  By Geophysical
     Methods (1971), U. S. Environmental Protection Agency,  Research
     Series 14010  EHN.

86.  International Minerals and Chemical Corp., Skokie, Illionis,
     Utilization of  Phosphate Slime (1971), Office of Research and
     Monitoring, U.  S. Environmental Protection Agency Research
     Series 14050  EPU.

87.  Island Creek Coal Company, Holden, West Virginia and Cyrus Wm.,
     Rice  Division, NUS Corp., Pittsburgh,  Pennsylvania, Feasibility
     Study of Mining Coal in an Oxygen Free Atmosphere (1972), Office
     of Research and Monitoring, U. S. Environmental Protection
     Agency, Research Series 14010 DZM.

88.  Jackson, Jesse  Jr., Total Utilization of Fly Ash (1972), 3rd
     Mineral Waste Utilization Symposium.

89.  Jacobs, H.  L.,  Acid Neutralization (1947), Chemical Engineering
     Process, Vol. No. 43, No. 5.

90.  Johns-Manville  Products Corporation, Rotary Pre-Coat Filtration
                              - 376 -

     of Sludge from Acid Mine Drainage Neutralization (1971), U. S.
     Environmental Protection Agency, Water Pollution Control Re-
     search Series 14010 DII.

91.  Jones, Donald C.,  Getting the Facts at Hollywood, Pennsylvania
     (1970), Coal Mining and Processing, 7. (8) pp. 18-33.

92.  Jones, J. L., Jr., Arminger, W. H., and Hungate, G. C.,  Seed
     Ledges Improve Stabilization of Outer Slopes on Mine Spoil (1973),
     Research and Applied Technology Symposium on Mined Lands

93.  Jukkola, W. H., Steinman, H. E. , and Young,  E. F., Coal  Mine
     Drainage Treatment (1968), 2nd Symposium on Coal Mine Drain-
     age Research, Mellon Institute, Pittsburgh, Pennsylvania.

94.  Kenehan, Charles B., and Flint, Einar P., Bureau of Mines Re-
     search Programs on Recycling and Disposal of Mineral-,  Metal-,
     and Energy Based Solid Waste (1971),  U. S. Department of Inter-
     ior, Bureau of Mines Information Circular 8529.

95.  Kenehan, Charles B., Kaplan, R. S.,  Dunham, J. T., and
     Linnehan, D. G., Bureau of Mines Research Programs on Re-
     cycling and Disposal of Mineral-, Metal-, and Energy-Based
     Wastes (1973), U. S. Department of Interior, Bureau  of Mines
     Information Circular 8595.

96.  Kennedy, James L., Sodium Hydroxide Treatment of Acid Mine
     Drainage, U. S. Environmental Protection Agency, National
     Research Center.

97.  U.S. Department of the Interior, Water Quality Management Pro-
     blems in Arid Regions (1969), Water Research Center, Federal
     Water Quality Administration,  Ada, Oklahoma,  U.S. Environ-
     mental Protection Agency Research Series 13030 DYY.

98.  Kosowski, Z. V., and Henderson, R.  M., Design of Mine Drainage
     Treatment Plant at Mountaineer Coal Company (1968), 2nd Sym-
     posium on Coal Mine Drainage Research,  Mellon Institute,  Pitts-
     burgh,  Pennsylvania.
                               - 377 -

 99.  Kremen, S.  S. etal, Reverse Osmosis Field Testing on Acid
      Mine Waters at Norton, West Virginia (1970), Office of Saline
      Water Report GA-9921, Gulf General Atomic, Inc.

100.  Kuo, C.  H., Pressure Behavior in Subsurface Disposal of Liquid
      Industrial Waste (1972), Journal Water Pollution Control Federa-
      tion, Dec.

101.  Lisanti,  A. F., Zabban, Walter, and Maneval,  D. R., Techni-
      cal and Economic  Experience in the Operation of the Slippery
      Rock Creek Mine Water Treatment Plant (1972), 4th Symposium
      on Coal Mine Drainage Research, Mellon Institute,  Pittsburgh,

102.  Lovell, Harold L., The Control and Properties of Sludge Pro-
      duced from the Treatment of Coal Mine Drainage Water by Neu-
      tralization Processes (1970), 3rd Symposium on Coal Mine
      Drainage Research, Mellon Institute, Pittsburgh, Pennsylvania.

103.  Lynch, Maurice A., Jr., and Mintz, Milton S., Membrane and
      Ion-Exchange Processes — A Review (1972), Journal American
      Water Works Assoc. 64 (11) pp. 711-19.

104.  Maneval, David R., The Little Scrubgrass Creek AMD Plant
      (1968), Coal Mining and Processing 5_ (9) pp. 28-32.

105.  Maneval, D. R., and Lemezis,  Sylvester, Multi-Stage Flash
      Evaporation  System for the Purification of Acid Mine Drainage
      (1970), Society of Mining Engineers, AIME Fall Meeting, Pre-
      print 70-B-303, St. Louis, Missouri.

106.  Maneval, D. R. , and Lemezis,  Sylvester, Multi-Stage Flash
      Evaporation  System for the Purification of Acid Mine Drainage
      (1972), Society of Mining Engineers, AIME, Transactions 252,
      March, pp. 42-45.

107.  Mason, Richard H., Twofold Attack on the Drainage Problem
      (1972), Coal Mining and Processing 9 (10), October, pp. 44-48.
                               - 378 -

108. May, Morton and Lang, Robert, Reclamation of Strip Mine Spoil
     Banks in Wyoming (1971),  University of Wyoming Agricultural
     Experiment Station Research, Journal 51.

109. McCarthy, Richard E., Preventing the Sedimentation of Streams
     in a Pacific Northwest Coal Surface Mine (1973), Research and
     Applied Technology Symposium on Mined-Land Reclamation.

110. McCrea,  D. H., and Cinquegrane, G. J., Leister, R.  J.,  and
     Forney, A. J., Evaluation of Solid Mineral Wastes for Removal
     of Sulfur from Flue Gases (1972), 3rd Mineral Waste Utilization

111. Means Building and Construction Cost Data,  31st Annual Edition

112. Michigan Technological University,  Houghton, Michigan,  Storage
     and Disposal of Wastes Resulting from the Concentration  of Low
     Grade Iron Ore (1972), U. S. Environmental Protection Agency,
     Project No. 14010 FVD.

113. Mighdoll, M.  S., Leadership for Recycling: Economic and En-
     vironmental Priorities (1972), 3rd Mineral Wastes Utilization

114. Mihok, E. A., et al, Mine Water Research — The Limestone
     Neutralization Process (1968), U. S.  Department of  Interior,
     Bureau of Mines Information Circular, Report of Investigation

115. Mills, Thomas C., Baker, Burton C., Hittman Assoc., Inc.  and
     Maryland Department of Water Resources, Guidelines for Ero-
     sion and Sediment Control Planning and Implementation (1972),
     Office of Research and Monitoring, U.S.  Environmental Pro-
     tection Agency Research Series R2-72-015.

116. Missouri Basin Engineering Health Council,  Cheyenne, Wyoming,
     Waste Treatment Lagoons — State of the Art (1971), U. S. En-
     vironmental Protection Agency Research Series 17090  EHX.
                               - 379 -

117. Monogahela River Mine Drainage Remedial Project and the Ad-
     visory Work Group, Handbook of Pollution Control Costs in Mine
     Drainage Management (1966), U. S. Department of Interior,
     Federal Water Pollution Control Administration.

118. Montana Department of Natural Resources and Conservation,
     Coal Development in Eastern Montana — A Situation Report of
     the Montana Coal Task Force (1973), Helena, Montana.

119. National Association of Counties Research Foundation, Washing-
     ton, D. C., Urban Soil Erosion and Sediment Control (1970),
     U.S.  Environmental Protection Agency Research Series 15030

120. Nickeson,  Floyd H.,  Republic Steel Counteracts Acid Mine
     Drainage (1970), Coal Mining and Processing I (9), September,
     pp. 36-38.

121. Parizek, R. R., and Tarr, E.  G., Mine Drainage Pollution Pre-
     vention and Abatement Using Hydrogeological and Geochemical
     Systems (1972), 4th Symposium on Coal Mine Drainage Research.,
     Mellon Institute, Pittsburgh, Pennsylvania.

122. Parizek, R. R., Jacobs, L. T., Sopper, W. E., Myers, E.A.,
     Davis, D.  E., Farrel,  M. A., and Nesbitt,  J. B., Wastewater
     Renovation and Conservation,Administrative  Committee on Re-
     search,  Penn State University Study No. 23.

123. Pettibone,  Howard C.,  and Kealy, C. Dan,  Engineering Proper-
     ties and Utilization Examples of Mine Tailings (1972), 3rd Min-
     eral Waste Utilization Symposium.

124. Peterson,  J.  R.,  and Gschwind,  J.,  Amelioration of Coal Mine
     Spoils with Digested Sewage Sludge (1973), Research and Applied
     Technology Symposium on Mined-Land  Reclamation.

125. Pennsylvania Department of Environmental Resources., Spray
     Irrigation Manual  —• A guide to Site Selection and System Design
     (1972), Bureau of Water Quality Management Publication No.  31.
                              -380 -

126.  Pennsylvania Department of Health, Division of Sanitary Engi-
      neering, Mine Drainage Manual (1966),  Publication No. 12, 2nd

127.  Pollio, Frank and Kunin, Robert, Ion Exchange Processes for
      the Reclamation of Acid Mine Drainage Waters (March 1967),
      Environmental Science & Technology, J_ (3).

128.  Potomac Engineering and Surveying,  Petersburg,  West Virginia,
      Feasibility Study of a New Surface Mining Method (1972), Pollu-
      tion Control Analysis Section, U.S.  Environmental Protection
      Agency Project No. 68-01-0763.

129.  Powell, J.  H.,  and Vickland, H.  I., Preliminary  Evaluation of
      the Electrodialysis Process for Treatment of Acid Mine Drainage
      Waters (1968),  Final Report to the Office of Saline Water, Con-
      tract 14-01-0001-1187,  Unpublished.

130.  Reid,  G. W. , and Streebin, L. E. , University of  Oklahoma,
      State of the Art Evaluation  of Petroleum and Coal Wastes (1970),
      U. S. Environmental Protection Agency Research Series 12050

131 .  Results of studies performed by Penn Environmental Consultants,
      Pittsburgh, Pennsylvania.

132.  Rex Chainbelt,  Inc., Reverse Osmosis  Demineralization of Acid
      Mine Drainage (1972), Office of Research  and Monitoring, Water
      Pollution Control Research Series 14010 FQR, U.S. Environ-
      mental Protection Agency.

133.  Rex Chainbelt,  Inc., Treatment of Acid Mine Drainage by Reverse
      Osmosis (1970), Federal Water Quality Administration, Water
      Pollution Control Research Series 14010 DYK.

134.  Riley, Charles  V.,  Furrow Grading-Key to Successful Reclama-
      tion (1973), Research and Applied Technology Symposium on
      Mined-Land Reclamation.
                               -381  -

135.  Robins, John D.,  and Zaval, Frank J., Water Infiltration Con-
      trol to Achieve Mine Water Pollution Control (1973),  Office of
      Research and Monitoring Research Series R2-73-142 (14010
      HHG), U. S. Environmental Protection Agency.

136.  Rose, John L., Treatment of Acid Drainage by Ion Exchange
      Process,  3rd Symposium on Coal Mine Drainage Research -
      Preprints, Mellon Institute,  Pittsburgh, Pennsylvania, May

137.  Saperstein, L. W., Short Course on Longwall Mining,
      Penn State University,  State College, Pennsylvania.

138.  Sceva, Jack E., Water Quality Consideration for the Metal Min-
      ing Industry in the Pacific Northwest (unpublished), U.  S. En-
      vironmental Protection Agency Region 10, Seattle, Washington.

139.  Schroeder, W. C., et al,  Study and Analysis of the Application
      of Saline Water Conversion Processes to Acid Mine Waters
      (1966), Office of Saline Water, Progress Report No. 199.

140.  Scott, Robert B., Evaluation of Bulkhead Seals (1972), Office of
      Research and Monitoring,  National Environmental Research
      Center, Rivesville, West Virginia.

141.  Scott, Robert B., Hill,  Ronald D., and Wilmoth, Roger C., Cost
      of Reclamation and Mine Drainage Abatement  —  Elkins Demon-
      stration Project (1970),  Water Quality Office,  U. S.  Environ-
      mental Protection Agency, Robert A. Taft Research Center,
      Cincinnati,  Ohio.

142.  Secor, E. S., and Saperstein, L. W. , Improved Reclamation
      Potential with the  Block Cut Method of Contour Stripping  (1973),
      Presented to Research and Applied Technology Symposium on
      Mined-Land Reclamation.

143.  Selmeczi, Joseph G., Design of Oxidation Systems For Mine
      Water Discharges, Fourth Symposium on Coal Mine Drainage
      Research, Pittsburgh, Pennsylvania, April 1972.
                               -382 -

144.  Singer, P. C., and Stumm, W.,  Oxygenation of Ferrous Iron
      (1969), Federal Water Pollution Control Admininstration Re-
      search Series 14010.

145.  Skelly and Loy, Engineers and Consultants, Alder Run Water-
      shed,  Acid Mine Drainage Pollution Abatement Project,  Pennsy-
      lvania Department of Environmental Resources.

146.  Skelly and Loy, and Baker-Wibberley and Assoc., Inc., Cas-
      selman River, Cherry Creek, Northern Youghiogheny River
      Mine Drainage Pollution Water Survey (1973),  Department of
      Natural Resources,  State of Maryland.

147.  Skelly and Loy/Zollman Associates, Inc., Harrisburg,  Pennsyl-
      vania and Baltimore, Maryland, Preparation of Plans and
      Specifications For Pollution Abatement Activities in Cherry
      Creek Watershed, Maryland, Appalachian Regional Commission
      Contract No. 73-35/RPC 767.

148.  Skelly and Loy, Engineers and Consultants, Clearfield Creek
      and Moshannon Creek, Mine Drainage Pollution Abatement Pro-
      ject (1973), Pennsylvania Department of Environmental Re-

149.  Skelly and Loy, Engineers and Consultants, Muddy Run Watei—
      shed,  Mine Drainage Pollution Abatement Project (1971), Pen-
      nsylvania Department of Environmental Resources.

150.  Skogerboe, Gaylord V., Colorado State University, Ft.  Collins,
      Colorado,  and Law,  J.  P.,  Kerr, Roberts., F.W.Q.A., Ada,
      Oklahoma, Research Needs for Irrigation Return Flow Quality
      Control (1971), U. S.  Environmental Protection Agency  Research
      Series 13030.

151.  Soil Conservation Service,  South Building, 14th and Independence
      Avenue, S. W., Washington, D. C., 20250.

152.  Stanley Consultants,  Feasibility Study - Upper Meander Creek
      Mine Drainage Abatement Project (1971), U. S. Environmental
                              -383 -

     Protection Agency, Research Series 14010 HBQ.

153. State of Maryland, Department of Water Resources, Deer Park
     Daylighting Project, U.S. Environmental Protection Agency
     Project No. 801353.

154. Sutton, Paul, Establishment of Vegetation on Toxic Coal Mine
     Spoils (1973), Research and Applied Technology Symposium on
     Mined-Land Reclamation.

155. The American Metals Climax Inc.,  Climax Molybdenum Mine,
     Climax, Colorado.

156. The Dow Chemical Company, Anion Resin - Hydrogen Cycle,
     Idea± Exchange 2 (4), (October,  1972).

157. The Dow Chemical Company, Basic Demineralization,  Ideai
     Exchange 2_ (1), (January, 1972).

158. The Dow Chemical Company, Cation Resin-Hydrogen Cycle,
     Idea ± Exchange 2_ (2), (April,  1972).

159. The Dow Chemical Company, Fundamentals of Ion  Exchctnge,
     Idea- Exchange _!_ (1), (January,  1971).

160. The Dow Chemical Company, Weak Acid Cation Resins, Ideal
     Exchange 2_ (3), (July, 1972).

161, The Ohio  State University Research Foundation, Acid Mine
     Drainage  Formation and Abatement (1971), U. S. Environmental
     Protection Agency Research Series 14010 FPR.

162. Truax-Traer Coal Company, Control of Mine Drainage for Coal
     Mine  Mineral Wastes (1971), U. S. Environmental Protection
     Agency Research Series 14010 DDH.

163. Tybout, R. A., A Cost-Benefit Analysis of Mine Drainage (1968),
     2nd Symposium on Coal Mine Drainage Research,  Mellon Insti-
     tute,  Pittsburgh, Pennsylvania.
                               - 384 -

164.  Tyco Laboratories, Inc., Electrochemical Treatment of Acid
      Mine Waters,  Environmental Protection Agency, Water Pollution
      Control Research Series 14010 FNQ 02/72.

165.  U. S. Department of the Interior, A Story of Operation Backfill
      (1964), U. S. Government Printing  Office, Washington, D. C.

166.  U. S. Department of the Interior, Study of Strip and Surface
      Mining in Appalachia (1966), Interim Report to the Appalachian
      Regional Commission.

167.  Underwater Storage, Inc. and Silver Swartz, Ltd., Washington,
      D. C., Control of Pollution by Underwater Storage (1969), U.  S.
      Environmental Protection Agency Research Series 11020 DWF.

168.  Uniroyal Inc., Use of Latex as a Soil Sealant to Control Acid
      Mine Drainage (1972), U. S.  Environmental Protection Agency
      Research Series 14010 EFK.

169.  U. S. Army, Corps of Engineers, Wastewater Management by
      Disposal on the Land (1972), Coal Regions Research and Engi-
      neering  Laboratory Special Report 121 .

170.  U. S. Department of Agriculture, Soil Conservation Service,
      South Building, 14th and Independence Avenue, S.  W., Washing-
      ton, D. C., 20250.

171.  U. S. Department of Health,  Education and Welfare, Disposition
      and Control of Uranium Mill Tailings Piles in the Colorado River
      Basin (1966), Federal Water Pollution Control Administration,
      Region VIII,  Denver, Colorado.

172.  U.S. Department of the Interior, Bureau  of Mines, Mineral Facts
      and Problems,Bulletin 630 (1972), U.S. Government Printing
      Office,  Washington, D. C.

173.  U.S. Department of the Interior, Cost Analysis of Model  Mines
      for Strip Mining Coal in the United States  (1972),  U. S. Govern-
                                - 385 -

     ment Printing Office, Washington,  D. C.

174. U.  S. Department of the Interior,  Effects of Placer Mining on
     Water Quality in Alaska (1969), Federal Water Pollution Control
     Administration,Northwest Region.

175. U.  S. Department of the Interior,  Final Environmental State-
     ment, Demonstration-Hydraulic Backfilling of Mine Voids in
     Scranton,  Pennsylvania, FES  72-11.

176. U.  S. Department of the Interior, Mine Subsidence-Extent and
     Cost of Control  in a Selected Area (1971), Bureau of Mines In-
     formation Circular 8507,  U.S. Government Printing Office,
     Washington,  D.  C.

177. U.S. Department of the Interior, Methods and Costs of Coal Re-
     fuse Disposal and Reclamation (1973), Bureau of Mines, Informa-
     tion Circular 8576,  U.S. Government Printing Office, Washing-
     ton, D. C.

178. U.S. Department of the Interior,  Pennsylvania AnthrcLcite Refuse-
     A Survey of  Solid Waste from  Mining and Preparation, Bureau of
     Mines, Information  Circular 8409, U. S.  Government Printing
     Office, Washington, D. C.

179. U.  S. Department of the Interior,  Surface Mining and Our En-
     vironment (1967),  U. S. Government Printing Office, Washington,
     D.  C.

180. U.  S. Department of the Interior,  Sul-biSul Ion Exchange Pro-
     cess = Field Evaluation on Brackish Waters (may 1969), Office of
     Saline Water, Progress Report No. 446.

181 . University of Maryland School of Law, Legal Problems of Coal
     Mine Reclamation (1972), U.S. Environmental Protection Agency
     Research Series 14010 FZU.

182. Utah State University Foundation,  Logan, Utah,  Characteristics
     and Pollution Problems of irrigation Return Flow (1970), U. S.
                               -386 -

      Environmental Protection Agency Research Series  13030.

183.  Vasan, Srini,  Utilization of Florida Phosphate Slimes (1972),
      3rd Mineral Waste Utilization Symposium.

184.  Virginia Water Resources Research Center, Research Program
      1972 - 1973, Virginia Polytechnic Institute and State University,
      Blacksburg, Virginia.

185.  Westinghouse Electric Corp., Water Province Department,
      Summary Report of Phase I of the Feasibility Study of Applica-
      tion of Flash Distillation Process for Treatment of  Acid Mine
      Drainage Water (1965),  Report to Pennsylvania Department of
      Mines and Mineral Industries.

186.  Westinghouse Electric Corp., Wilkes-Barre Demineralization
      Plant — Cost of Water Report (1971), Report to Pennsylvania
      Department of Environmental Resources.

187.  West Virginia  University, Morgantown, West Virginia, Under-
      ground Coal Mining Methods to Abate Water Pollution (1970), U.
      S.  Environmental Protection Agency Research Series 14010 FKK.

188.  Weyerhauser Company, Silva Fiber Specifications, Tacomo,
      Washington, 98401 .

189.  Williams, George P., Jr., Changed Spoil Dump Slope Increases
      Stability on Contour Strip Mines (1973), Research and Applied
      Technology Symposium  on Mined-Land Reclamation.

190.  Wilmoth, Roger C.,  Scott, Robert B.,  and Hill,  Ronald  D. ,
      Combination Limestone-Lime Treatment of Acid Mine Drainage
      (1972), 4th Symposium on Coal  Mine Drainage Research,  Mellon
      Institute, Pittsburgh, Pennsylvania.

191.  Wilmoth, Roger C.,  Hill, Ronald P., Mine Drainage  Pollution
      Control  by Reverse Osmosis (1972), American Institute of Mining,
      Metallurgical and Petroleum Engineers.
                                - 387 -

192. Wilmoth R. C., Mason, D. G., and Gupta, M., Treatment of
     Ferrous Iron Acid Mine Drainage by Reverse Osmosis (1972),
     4th Symposium on Coal Mine Drainage Research,  Mellon Insti-
     tute, Pittsburgh, Pennsylvania.

193. Witmer, Fred  E., Reusing Waste Water by Desalination (1973),
     Environmental Science and Technology, 7 (4), pp. 314-318.

194. Yen, S. and Jenkins, C. R.,  Disposal of Sludge from Acid Mine
     Water Neutralization (1971), Journal Water Pollution Control
     Federation, 53_ No. 4, pp.  679-688.

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199. Sandoval,  F.  M., J. J. Bond, J. F. Power, and W. O. Willis,
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210.  ICOS Corporation of America, 3 The I. C.O.S. Company in the
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