WATER POLLUTION CONTROL RESEARCH SERIES • 14010 FKK 12/70
  Underground Coal Mining Methods
       to Abate Water Pollution
ENVIRONMENTAL PROTECTION AGENCY • WATER QUALITY OFFICE

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       WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe
the results and progress in the control and abatement
of pollution in our Nation's waters.  They provide a
central source of information on the research, develop-
ment, and demonstration activities in the Environmental
Protection Agency, Water Quality Office, through inhouse
research and grants and contracts with Federal, State,
and local agencies, research institutions, and industrial
organizations.

Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Head, Project Reports
System, Office of Research and Development, Environmental
Protection Agency, Water Quality Office, Washington, D.C.
20242.

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Underground Coal Mining Methods to  Abate  Water  Pollution:


             A State of the Art Literature Review
                          Coal Research Bureau
                        West Virginia University
                     Morgantown, West Virginia  26506
                                for the
                      ENVIRONMENTAL PROTECTION AGENCY
                           Project No.  14010 FKK
                                December  1970
       For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price 60 cents
                               Stock Number 5601-0094

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                   EPA Review Notice

This report has been reviewed by the Water Quality
Office, EPA, and approved for publication.  Approval
does not signify that the contents necessarily
reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names
or commercial products constitute endorsement or
recommendation for use.

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                               ABSTRACT
This review includes published information about the abatement of harm-
ful drainage from underground coal mines.  Although much has been written
on mine water management, very little literature is available on the
specific area of mining to prevent the formation of acid water.  The
references included in this report, which involve mining engineering and
mining oriented hydrology studies, span that period of time when water
quantity rather than quality was the major consideration.

Physical approaches to the problem of preventing water entry into coal
mines, as a means to broaden water improvement techniques beyond removal
and treatment, have only recently been undertaken.  Some new approaches
to this problem are (a) land management to control surface and sub-
surface diversion, (b) the skillful and favorable exploitation of water
carrying strata, and  (c) implementation and innovation of mining methods
and techniques which are conducive to improved water quality.

Chemical approaches being considered or presently under investigation
involve (a) the use of underground silica gel solutions to prevent the
formation of acid mine water, (b) the experimental use of an inert gas
atmosphere in active mines to prevent acid water formation and (c) the
search for new and the refinement of existing grouting agents.

This report is submitted in partial fulfillment of the requirements of
Project No. 14010 FKK under the sponsorship of the Water Quality Office,
Environmental Protection Agency and the Coal Research Bureau of West
Virginia University.
                                  iii

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                                 CONTENTS




Section                                                         Page
  I  CONCLUSIONS                                                 1




 II  RECOMMENDATIONS                                             3




III  INTRODUCTION                                                5




 IV  GROUND WATER HYDROLOGY                                      9




            Ground Water Occurrence




            Water Movement and Mining




            Water Entrance Into Mines




            Geocheraical Studies




  V  MINE WATER MANAGEMENT                                      17




            Preventing Water Entry




            Preventing Acid Water From Forming




            Underground Disposal of Acid Water




 VI  MINE CLOSING                                               29




            Mine Seals




            Inert Gas




VII  UNIQUE METHODS                                             35




            Inert Gas




            Revised Mining Methods




VIII RESEARCH NEEDS                                             39




  IX ACKNOWLEDGMENTS                                            41




   X REFERENCES                                                 43




  XI GLOSSARY                                                   49

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                                 FIGURES




                                                              PAGE





 1  COAL FIELDS OF UNITED STATES                                6




 2  GENERALIZED DIAGRAM OF GROUND WATER OCCURRENCE             10




 3  DIAGRAM SHOWING PERCHED WATER TABLE                        H




 4  GROUND WATER CONE OF DEPRESSION                            12




 5  GROUND WATER MOVEMENT                                      14




 6  DIAGRAM SHOWING WATER RING                                 19




 7  SURFACE SUBSIDENCE SINGLE HOLE                             20




 8  SUBSIDENCE AFTER COMPACTION AND REGRADING                  20




 9  SUBSIDENCE HOLE                                            21




10  GROUND MOVEMENT AROUND AN EXCAVATION                       22




11  COST COMPARISON OF THREE DRAINAGE PLANS                     24




12  GENERAL LITHOLOGY OF DISPOSAL WELL                         27




13  WET MINE SEAL                                              30




14  EXPENDABLE GROUT RETAINERS                                 31




15  AGGREGATE PLUG DETAIL                                      33




16  AQUIFER DEWATERING SYSTEM                                  36

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                                SECTION I

                               CONCLUSIONS

1.  Mine drainage constitutes surface or ground water which flows from
mines or mine sites and is usually characterized by concentrations of
acidity or alkalinity.

2.  The regional geology controlling the ground water flow pattern in
conjunction with the life cycle mining plan can serve as a basis for
making decisions about quality of water that can be expected to be
encountered.

3.  In regard to the prevention and control of acid water formation in
underground coal mines, much is left undone in research and education:

    (A)  Very little literature is available on this specific subject
    although much has been written on water management in underground
    mines.

    (B)  Little or nothing is contained in the text books and curricula
    used in mining departments at colleges and universities with the
    result that educational offerings may be seriously deficient in
    these areas.

4.  Prohibiting water entry into underground coal mines is the best
method of preventing water pollution.  Since this is not possible
as mining operations are extended, preventing water or oxygen from
contacting acid producing material may offer the next best alternative.

5.  More emphasis is needed during the mine planning stage on steps to
prevent water pollution.  Such life cycle considerations as type of
mining, sequence of development and spatial configuration as well
as the elements of the drainage network and final network organization
and extent must be considered.

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                              SECTION II

                             RECOMMENDATIONS

1.  Mining to prevent and control underground acid formation should begin
    with education imparted through:

    (A) Course work at mining schools to teach prospective engineers.

    (B) Training of engineers presently employed in the mining industry
        through appropriate mining extension courses.

2.  Considerable need exists to devote more attention to:

    (A) Hydrogeologic studies of mining areas to enhance the
        planning of new mines and the abatement program of
        exis ting mines.

    (B) Additional research to explore methods of dewatering the
        strata associated with mining areas.

    (C) Further effort to develop sealants for preventing contact
        between water or oxygen and the acid producing material
        associated with the coal seam.

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                              SECTION III

                             INTRODUCTION

The production of harmful pollutants from coal mines and/or from coal
and associated strata has been a recognizable fact in the United States
for over two hundred and seventy years.  In 1698, Gabriel Thomas
observed (1) that the colored water flowing from streams in this country
was similar to that which flowed from the coal mines in Wales.  Hence,
water pollutants such as acid x^ere being produced before any known coal
mines were operating in this country.  The coal mining industry has con-
tributed to the increase of pollution by exposing large amounts of sulfide
materials that enable the reaction of water, oxygen and sulfur containing
materials to form acid.

A map of the United States coal fields can be seen on Figure 1.  The
anthracite regions of Pennsylvania, although small when compared to
the total reserves, have produced some of the country's major water
problems.  The map indicates the extent of bituminous reserves of the
Appalachian and midwest regions.  Also evident are the bituminous, sub-
bituminous and lignite coal reserves in the west which have recently come
into greater demand.  Acid mine pollution is encountered in numerous
states, but the major problem is found in the Ohio, Susquehanna, and
Potomac River basins. (2)

Most coal beds contain some sulfur which may be in the inorganic, sulfate,
or sulfide form, and thus have the potential to produce sulfuric acid.
However, much of the strata that overlays the coal beds also contains
acid neutralizing materials.  Therefore, the amount of acid prbduced
depends upon the amount of both acid and alkali materials that dissolve
in the water in any given mine.

The common sources of sulfurous material in the seam or surrounding rock are
generally called sulfur balls or "nigger heads" by the miners.  Sulfur
balls that have been observed^) seem to be equally divided between
those containing sulphuritic iron capable of producing sulfuric acid
upon oxidation and those that are primarily calcium carbonate.  It has
been observed in many instances that two types of water, acid and alka-
line, are being produced in the same mine.  A study of the geological strata
and a survey of subsidence, faults and sulfur balls will usually give some
indication of why this happens.
The reaction of pyrite (FeS2) with oxygen and water to form ferrous
sulfate (FeS04) an<^ sulfuric acid (l^SO^) by a series of complex chemical
interactions is well documented but not well understood. v^,5;   However,
it is well known that the reactions to form the acid cannot occur unless
all three constituents are present.  Since pyrite is inherent in most coal
seams and air is needed to sustain the miner, the most logical answer is
to eliminate water infiltration into the mine, or to remove it from the
mine before acids can form.

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                                                   Anthrocite




                                                   Bituminous




                                                   Subbituminous




                                                   Lignite & Brown Coal
Fig. I-  Coal Fields  of the  United States.

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The most common method of eliminating water infiltration has been seal-
ing abandoned mines with cement or concrete block.  Much success has also
been accomplished where the mine was flooded with water preventing oxygen
from contacting the pyrite.  Those seals which have been placed above the
water table have had minimal success, because the strata usually breaths
and permits the oxygen supply to replenish.  Thus, current methods of
using wet seals will not stop pollution entirely, but may, in many cases,
be of some help.

This report encompasses a literature survey of acid mine water abatement
measures and mining hydrology.  Mine water management is examined from
the aspects of preventing water entry, preventing formation of acidic
waters, underground water treatment, and water removal.  Sealing methods
and unique methods in deep mines are also discussed.  Those areas where
further research efforts might be applied are noted in the section on
research needs.

This state of the art report completes the goal of Phase I of a project
for investigating methods that can be utilized for the reduction of harm-
ful drainage from underground coal mines.  Phase II of the program will
involve on-site mine visitations to evaluate those practices and techniques
which are currently employed, although not necessarily published, in under-
ground coal mines for the prevention or reduction of harmful mine drainage.
Phase III of the program will be an evaluation and publication of
information obtained during Phase II of the program.

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                              SECTION IV

                         GROUND WATER HYDROLOGY

Underground and strip mining' ' ' produce different hydrologic environ-
ments.  Many underground mines are below the zone that is completely
saturated with water and the mine openings may cause new and continuous
contact between sulfurous material and water which flows from the saturated
zone to the workings.  Strip mines are usually above the zone of continuous
saturation and contact between sulfurous material and water is generally
restricted to periods of precipitation.  A full appreciation of the
problem of water pollution caused by drainage from deep mines requires
a basic understanding of occurrences and movement of water in the ground
and the modes of ground water entrance into mining areas.


                         Ground Water Occurrence

The most important factor in ground water occurrence is the surface and
sub-surface geology.  ' '  '  '     Over most of the earth a zone filled
with both air and water (the zone of aeration) overlies a zone completely
filled with water (the zone of saturation).  The surface between these
two zones is the water table and in general the water table conforms to
the ground surface topography, (see figure 2).  Underground geologic
formations may, however, alter this general rule.  When water flows
through a specific geologic formation bound above and below by impermeable
strata, the formation is termed a confined aquifer and the water is termed
artesian water.  Formations that allow water to flow freely and seek its
own level, in response to precipitation and discharge changes, are termed
unconfined aquifers.

A special case of unconfined ground water, termed a perched water table,
is a saturated zone located above the main body of ground water and
separated from it by a zone of impermeable strata, (see figure 3).
Strata that will not transmit the flow of water and has no storage
capacity is termed an aquiclude^-'-' (see figure 2).
                        Water Movement and Mining

The movement of ground water is usually'  >'  from topographic high
elevations to topographic lows, but mining presents a specific set of
circumstances in relation to ground water movement, (see figure 4 for
graphic illustration).

                "When a shaft is sunk below the natural x^ater table
                in rock that is reasonably permeable and homogeneous,
                pumping immediately begins to drain water out of the
                pores and crevices in the rock.  As pumping continues.
                the water level is artificially depressed and assumes
                much the shape that a stretched membrane would have
                if one were to punch it downward with a stick. That

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                                                               RECHARG E
                                           OUTCROP OF  \  IMPERMEABLE  STRATA
                                              "PIEZOMETRIC SURFACE'
                                          WATER FROM ARTESIAN WELLS RISE
                                          TO THIS LEVEL
    WATER  TABLE
                                   ZONE OF AERATION
                                   ZONE OF  SATURATION
                       CONFINED  AQUIFER  (SANDSTONE)
                            IMPERMEABLE  STRATA
Fig.2- Generalized  Diagram Showing The Water Table, Zones of Aeration  and  Saturation, Confined
       and  Unconfined Aquifers, an Aquiclude and an Artesian Water System.

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                     GROUND  SURFACE-
           ZONE     OF    AERATION
  V^-:vrv;'V-::V:f-;v::/i'^j'V>V" PERCHED' '•<:'•.'"".:•':<;•',•:.....
 j;~-.-•::••:<••; -:-"L-•.••/•»•.-.•? :'.?••..,• WATER  TABLE :•:-.-•.-.;.-.Jr4y.\^'.t.--
              ZONE  OF  IMPERMEABLE  STRATA
                     DRY      ZONE
 WATER  TABLE—-^
 .--• v. •*."-"•. 'j V7-V; •."••".V-" ;•"•.•"'-" !'•••". •• -"•. " •'*. • -', •' ':•' -:. '."•  "'
'/'•'•" '• ".' .'• -MAIN / B'ODY'. .'dF--"GROUND' -'.WATER +••• '.' .'">  C .•••"•••'.•"•
x  _  • •'>.-• ^ .•  f LI -.".',-  •••*•••-•'•„'."•.'• '•-.  .• .'  »  ' '   -.*....

 Fig.-3 - Diagram Showing Perched Water Table. After Linsley (12)
        is  to say, the water table has  the shape of a flat
        inverted cone with its apex  at  the shaft.  This is
        known as the cone of water-table  depression or the
        cone of unwatering.  Although in  terms  of strict
        geometry it is not a true cone, since its sides,
        viewed in cross section, are not  straight lines but
        curves which steepen toward  the shaft.   The flow of
        water into the shaft is heaviest  when pumping begins,
        but if sinking is stopped it gradually lessens and
        after some months becomes virtually constant.
        Accordingly, the cone of unwatering assumes a shape
        which is practically stable  as  the flow of water
        into the shaft reaches a state  of equilibrium
        with supply of water entering  the aquifer and
        percolating through it.  If  shaft-sinking is resumed,
        the process is repeated; the new  cone is deeper
        and requires a higher rate of  pumping to keep it
        drained.

        If  a drift is extended from  the bottom of the
        shaft, the cone of unwatering  is  no longer a
        symmetrical cone; what was formerly the point of
        the cone is elongated into a horizontal line, the
        water table sloping upward from it at both sides
        and at the ends.  If closely spaced crosscuts are
        driven from the drifts,  the  cone  assumes somewhat
        the form of a bathtub with flat-sloping sides.  If
        upper levels are now driven  from  the shaft they will
                            11

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                                                      CONE OF UNWATERING
                                                     AFTER SHAFT SINKING
WATER  TABLE BEFORE SHAFT SINKING
                                                                  CONE Of
                                                               UNWATERING
                                                               AFTER  ENTRY
                                                              DEVELOPMENT
                                    MAIN ENTRIES
        Fig.4-Diagram Showing Development of the Cone of Unwatering
               (Cone of Depression) As Mine Shaft  and Entries  are Developed.
                encounter little water until they are out  far  enough
                to reach the sides of the cone; then they  will begin
                to tap the water reservoir, but unless  they  extend for
                long distances they will not materially lessen the flow
                that enters the deepest workings."(15)

The creation of the cone of unwatering by shaft sinking provides  arti-
ficial topographic highs and lows and allows for the flow  of water into
the mine when the shaft is sunk through water-bearing strata.

Core drilling'16,17,18) ±s a means of detecting water bearing  strata,
measuring water level and water movement and is increasingly recognized
as a necessity for determining the economics of mining.  Water levels
and movement can be studied by plotting the core drilling  data on water
level contour maps, water level change maps and well hydrographs. (16)

One study(19) included the drilling of 28 bore holes and  the use  of 137
other private and public wells to determine the effect  of  deep mining
                                      12

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on ground water movement.  This data was correlated with information
gathered from seasonal and areal distribution of precipitation and
concluded that:

(A)  No two mines should be expected to be alike in environment, hydro-
     logy, source of pollution or treatment.

(B)  Mining can affect speed, course and quality of water moving through
     the mining area.

(C)  Mining accelerated the natural flow and hydrogeologic conditions
     already existing in the area basins.

(D)  Water under pressure, as a result of flow through strata located
     at elevations above the mine workings, can enter the mine from
     all directions including the floor (see figure 5).

(E)  The chemistry of the ground water depends primarily on the
     composition of the minerals with which it comes in contact.

(F)  Water samples collected at different depths varied widely in
     quality.  Waters at shallow depths were less mineralized than
     those taken at great depths.

(G)  Base flow (ground water contribution to stream flow) of acid
     waters was attributed to storage and slow release of deep and
     strip mine waters in the ground.  The percentage of mine drainage
     to total surface water drainage is greatest during periods of little
     or no precipitation.

(H)  Inter-basin movement of drainage across normal ground water divides
     is produced by the effects of mining.
                        Water Entrance Into Mines

During the construction or later development of many mines, water may be
encountered in various quantities due to local conditions.  Some mines(21,22)
are dry, whereas in others the weight of water to be removed is many
times that of the coal raised to the surface.

     (13 23)
Water   '    may enter mine workings in several ways:

(A)  From water bearing strata that is in contact with coal seams.

(B)  By entering shallow mines from the surface.

(C)  By entering through faults and fractures in coal seams
     and adjacent strata.

(D)  By entering active sections from abandoned workings.
                                        13

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                                             f
COAL  UNDERCLAY
                 A                                       B
        Fig.5- Diagram Showing Idealized Movement of Ground-Water to a
               Mine Entry.  From  Ward  B Wilmoth.  (20)
Water Bearing Strata
                                          (13)
Many of the rock beds associated with coal      are water  impervious;
however, sandstone beds in contact  with  coal  seams may be very porous
and transmit many thousands of gallons of water depending on  the  depth
at which the porous beds are encountered.  The  deeper the location(12,22,24)
of water bearing strata the less capacity the rocks have  to transmit
water due to the increasing pressure of  the overlying strata.
Water in Shallow Mines

Strata near the surface will have different hydrologic  characteristics
than strata at depth and it is  possible that shallow  mines will  encounter
more water than deep mines.

                "It is comparatively easy  for water to  per-
                colate to a certain varying depth as  a  consequence
                of the porosity of the surface rocks  which are in
                process of disintegration  by various  natural
                agencies.  Moreover, the rocks at limited depths
                are not subject to any great pressure and there
                                   14

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                is little tendency to close up fissures and cracks
                once formed.  At depths of less than 100 yards, seams
                are generally found very wet to work and storm water
                percolates rapidly into the workings.  In these
                pits a marked difference is found between the
                quantity of water pumped in summer and in winter.
                These effects are emphasized if the beds outcrop
                in the vicinity of the mine."(13)
Water Entrance Through Fractures
               / o c 0 A '?7^
Earth fractures   '  '   , such as faults, joint systems in rocks,
and fractures caused by surface subsidence allow water to enter under-
ground mines in various quantities.

Many faults,'-^) especially those that follow the strike of rock and
coal beds, can act as main drainage lines and can yield large quantities
of water when tapped by mine workings.

Joints in rock strata    , formed by deformation of the strata, increase
the porosity of otherwise impervious rock beds and may transmit water
from overlying aquifers into mine workings.

                         (13 21 27)
Many studies and reports   '   'on water drainage from mines
indicate that mine roof fracturing and resulting surface subsidence
after removal of mine roof supports, such as pillars and blocks, is one
primary cause of water entrance into deep mines.  Advance warning of
fractures in the vicinity of the mining area is reported^  '  ' to be
best discovered by core drilling and construction of sub-surface struc-
ture maps.
Water from Abandoned Workings

Besides earth fractures and strata that transmit water, abandoned
workings(13) that are broken into from active sections can cause large
quantities of water to enter a mine.  The(17) possiblity of guarding
against this by carrying a long drill hole ahead of the working face,
when it is known that abandoned workings are near, has been proposed.
                           Geochemical Studies

Geochemical and stratigraphic studies of the distribution of sulfur and
pyrite in relation to coal beds have received considerable attention.
A study's) that included a review of water analysis records on file
at the Pennsylvania Department of Health, Division of Sanitary
Engineering, was made of drainage from several coal beds and associated
strata.  The conclusion of this study is that there are variations in
the composition of water discharged from various coal seams and that
there are regional variations in water composition within single coal seams,
                                      15

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                         (29,30,31,32)
Other geochemlcal studies              have been  conducted using specific
coal seams to determine the distribution  and  depositional environments
of sulfur and pyrite within coal seams.

The results of these studies have shown that  it is possible to account
for variations in drainage  quality within a coal  seam when the deposi-
tional environment of  the coal seam  and surrounding rock beds is known.
                                   16

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                                SECTION V

                         MINE WATER MANAGEMENT

In the past, mine management has been concerned with removing water from
active mining sections primarily because it hampered the movement of
mining equipment and aggravated the working condition of the miners.
Pumping water to sumps and gravity drainage by ditching have proven
successful in mines for minimizing section down time due to water
influx.  However, with the advent of more strict pollution laws the
mining engineer must now be concerned with keeping water out of the
section and also with preventing it from causing pollution.  A review
of the handbooks and textbooks used in the mining engineering curricula
reveals that little has been written concerning acid mine water prevention
or control in underground coal mines.  Additionally, the review of
the curricula of mining schools indicates they are not teaching the
engineering students the necessary techniques of mine water management
as they relate to the abatement of mine water pollution.
                        Preventing Water Entry

The best way to reduce water problems is to prevent water from
entering the mine, either by surface diversion or by underground
diversion.  The prevention of water entry is not an easy job nor
one which conforms to a set formula.  Due to the sequence of mining,
topography, strata, and climate, it is difficult to predict the exact
mining conditions to be encountered.  Subsidence holes and faults
increase the amount of water entering the mine, while close bonded
rocks of high strength minimize seepage from overlying strata.

Subsidence which influences the inflow of water occurs only if the
depth is relatively shallow (less than a few hundred feet).  However,
there are exceptions to this general rule due to the varying structure
of the overlying rock and the general direction in which water flows
over the subsided area.  If the surrounding terrain drains into a
subsided area, this could greatly influence the amount of water
infiltration.

An examination of more than 250 mines in 1928 showed that the
average rate of infiltration for all the mines came to approximately
1,100 gallons per acre per day. (33)

Parizek stated at the 1970 SME Fall Meeting that a more recent survey
estimates the quantity of water leaking from the roof of underground
mines to be approximately 670 gallons per acre per day.'^4)  These
surveys indicate a range in the amount of penetration and it must be
understood that these rates of infiltration may vary within any
particular mine.
                                   17

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Surface Diversion

Surface diversion is an important aspect to consider when dealing with
the problem of water in coal mines.   The use of diversion ditches and
water rings (see Figure 6)  can greatly decrease the water and ice
problem encountered around  shafts.  Surface drains  and waterways or
flumes should be properly arranged to prevent waterlogging of the
surface beds.

Seepage can sometimes be eliminated by lining the old drainage
channels with concrete or bituminous coatings.  A more permanent
improvement, however, is to relocate the channel to non-caving or
impervious ground.(35)  in  many instances where coal has been
worked to the proximity of  an outcrop, the amount of water that
can infiltrate as a result  of surface drainage will increase.

The Coal Industry Advisory  Committee of ORSANCO has published case
histories of mining practices(36) used to prevent or abate water
infiltration into mines.  Two cases dealing with water entry due
to subsidence holes were designated No. la-12 and la-13, both of
which deal with the Lower Kittanning coal seam in eastern West
Virginia.  The first case history involved an underground room and
pillar operation where a subsided area, overlying a caved section that
had been mined and abandoned, intercepted and diverted normal surface
runoff into the mine.  To reduce the total volume of mine discharge,  the
entire area, consisting of  nearly an acre, was cleared.  The weathered
material was removed from within individual subsidence holes down to  bed
rock.  The holes were then backfilled in 12 to 24 inch layers.  Special
precaution was taken to restore the original contour of the surrounding
area.  The water problem was successfully curbed.  Although it was
impossible to determine at  that location, the control measure probably
prevented the entrance of air into the mine (see figures 7 and 8).
Under similar conditions, the vegetation should be  restored with a
combination of bushes, crown vetch and trees.

The second case history, No. la-13 reports on the success of using a
water barrier compound for  the sealing of individual surface subsidence
holes.  The subsidence was  located in a wooded area with rocky terrain
which did not allow for sufficient clearing and backfilling (see figure
9).  A sheet of 3/32 inch butyl compound was placed in the cleaned-out
hole and covered with compacted clay and dirt originally removed
from the hole.  Special care was taken to cover an  area large enough
to prevent water from getting under the butyl sheet and forming a
trench to the original subsidence hole.

Since subsidence holes allow large amounts of water to infiltrate into
the seam below, every precaution should be taken to prevent or cover  these
holes.  It has been observed(37) that any excavation made in the mine
releases the pressure above and allows the strata to flow in toward
the excavation from all directions (see figure 10).
                                    18

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                        DRAINAGE
                         PI PE
    GROUND
    SURFACE
Fig.6-  Idealized Cross  Section of Coal Mine Shaft Showing Application of a
        Water  Ring.
                                   19

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Fig.7-Surface  Subsidence  Single Hole. (36)
 Fig. 8—Subsidence After Compaction  and
        Regrading. (36)
              20

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Fig. 9- Subsidence Hole.   ( Cose History No.  la-13. From Coal Industry
        Advisory  Committee)  (36)

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                                                           SURFACE
             -                      --
           . V   i   \  X   XT/    /    /   /   /
                                        '   /   /  /   '
\\\\  \   \

   \\^  \   \  \
     \  \\  \  '
       \  \   \ v  ^  EXCAVATION
                                    jf \
                                  x      ^
          Fig.lO- Characteristic Lines of Ground Movement
                  Around an Excavation.   (After Grand) (37)
Underground Diversion

It is not generally possible  to  totally prevent water from entering a
coal producing area;  therefore,  some means of underground diversion
must be considered.

In the course of mining,  attention should alsqsbe given to prevention
of crack formation under  streams and rivers.      Sufficient coal
can be left in those areas  to prevent  the formation of cracks to the
surface.  This usually means  permanent support of the overburden and
will require leaving from 30  to  60 percent of the coal at depths up to
400 feet.  Since cracks to  the surface are not usually formed at depths
greater than 400 feet for beds up to 6 feet thick, many deep mines do not
have this particular problem  and complete extraction of the coal can be
carried out without undue trouble from surface water.(39)

When extracting progresses  near  the boundry line a sizable barrier should
be left, particularly if  the  seam is dipping away from the outcrop.  Under
such a situation, ground  water will have a tendency to infiltrate into
the coal seam and follow  the  dip. Sufficient barriers should also be
left when mining adjacent to  abandoned workings which might possibly
be inundated with water. (35,40)   -j^g width of barriers to abate such
water movement will depend  on several  factors such as angle of dip of
the seam, the vegetation  on or near the outcrop, and the adjacent
strata.  All factors should be considered separately for each mine and
possibly for each section of  the mine.
                                   22

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grouting

Another method of underground diversion is grouting.  In 1891 Albert
Francois(^1) developed a method of sealing a shaft below the permanent
water level by injecting a cementing agent into the strata under pressure,
This grout was found to set and displace the surplus water.  Cement
worked well in voids and in fissured or fractured ground, but the
process was ineffective in porous rock such as sandstone.  It has been
established experimentally that the width of voids in a formation must
be at least three times the diameter of the grout particle in order
to obtain effective penetration.(42)

The process of using a combination of cementation and silication helped
to improve the effectiveness of the grouts.  The chemicals employed in
the process are aluminum sulfate and sodium silicate, used in dilute
solutions with a gelatinous precipitate of aluminate silicate. (^5)  ^e
new combination process proved highly satisfactory for reduction of
porosity: and also proved advantageous because it formed a lubricant
which coated the sides of the fissures and thereby facilitated the
passage of cement.

The application or injection of the grouts could be used in shaft
sinking to cut the infiltration of water or to stop it completely.
The use of such agents, although widely accepted in other mining
operations, should be investigated to determine economic and engineering
feasibility for application in coal mining.
                    Preventing Acid Water From Forming

Under most conditions it is neither possible nor practical to keep
all water from entering a mine and contacting acid producing con-
stituents of the seam and surrounding strata.  The methods which may
be used  to prevent or minimize acid water formation are water removal
and treatment of acid forming materials.
Water Removal

The rapid removal of water infiltrating into a mine is most important in
preventing  the  formation of acid water.  Numerous studies by the Bureau
of Mines,v43,44,45) have been made of the anthracite region where removal
has been long recognized as a major problem.  The anthracite region
covers about 480 square miles and straddles two drainage basins—the
Susquehanna and the Delaware, although the major acid water problems have
centered around the Susquehanna basin.

Research was undertaken to develop a method for economic removal of
water pools in  the inundated reserves of the eastern field.  Methods
suggested were:(43,46) (a) the use of a drainage tunnel, (b) a central
underground pumping plant, and (c) a deep well pumping plant.  A comparison
                                    23

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                                    Pumping
                                     main-
                                    tenance,      Carrying
                         Initial    etc., 13       charge,       Total
                          Cost       years        3_ percent      Cost

Plan A, drainage       $1,999,000    Nil         $445,000     $2,444,000
tunnel

Plan B, Underground       830,000    $780,000      184,000      1,794,000
pumping plant

Plan C, deep-well         577,000     689,000      125,000      1,391,000
pumping plant

Note:  These are 1941 dollars and are presented  merely  to provide  an order
       of magnitude comparison

    Fig.II -Comparison of Costs for Three Drainage Plans.   (USBM

            Bulletin 491, 1950) (46)


of costs for the proposed plans are  shown in Figure 11.  These costs, while
obsolete, are presented as order of  magnitude  estimates  only.

A 1941 report expressed the concern  of the  operators who were faced with  the
rising cost of pumping mine water in order  to  maintain  mining operations.
Underground water pools, some of which contained several billion gallons,
were generally created by the inflow from adjacent mines which had inadequate
barrier pillars, and also from the mines which were idle during periods of
economic depression in the industry.   The industry was,  and still  is, trying
to control the problem by using central mine pumping stations equipped
with centrifugal pumps.(45)  Deep well pumps give satisfactory
operating results and are used increasingly when and where conditions are
favorable.  In comparison with bituminous fields, the problems in  the
anthracite region were and are different.   The work done in the anthracite
region was concerned with quantity more so  than  with the water quality.
The anthracite coal mining operators now find  themselves handling  a
problem which is mainly concerned with the  quality of the water.


Treatment of Acid Forming Materials

If the entry of water cannot be avoided, it may  be possible to prevent
the air-water-pyrite contact by the  use of  silica gel and, to a degree,
rock dusting of the exposed pyrite.


Sealants. Because of the needed reaction between pyrite, oxygen and water
to form sulphuric acid in underground coal  mines, it is believed  that  the
development of sealants, to prevent  the oxidation of pyrite as well as
                                   24

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to prevent contact with ground water, will greatly reduce the formation
of acid water.^  '

One such substance for the prevention of acid mine drainage water is  a
sodium silicate solution.

The use of sodium silicate to prevent the formation of acid mine drainage
was discussed^8) at the Third Symposium on Coal Mine Drainage Research
and the following two applications were emphasized both of which depend
upon saturating the strata in which the contaminating materials are
formed:

A.  The acidification of sodium silicate solutions resulting in the
    formation of stable, structurally strong gels.  Once formed,
    such a gel could modify hydrologic patterns and exclude water
    from contact with the pyrite precursor and thus either prevent
    leakage from the strata or inhibit formation of the contaminants.

B.  Alternately,, the precipitation of ferrous (or ferric)  silicate
    on the surface of individual pyrite, rocks, or soil particles
    to form an effective seal, insulating each entity from water.

The use of sodium silicate solutions has been tried only experimentally
on gob or refuse piles as an Environmental Protection Agency (EPA)  research
project.  The project, thus far, has shown only a potential value for
silica gel application and more field experimentation is needed before
its full value is known.  The solution, if proven successful,  could be
used underground and injected into the floor and roof or coated on the
ribs to abate the formation of pollutants.
Rock dusting.  Rock dust is used in all underground coal mines  to help
allay fine coal dust and prevent the propagation of an explosion.
Nothing can be found in the literature on the use of rock dust  under-
ground to treat acid mine water.  Rock dust is mentioned here simply
because it is an alkali substance (crushed limestone)  and can,  to some
degree, neutralize acid water flowing through the mine.  Its effective-
ness, however, is limited.  Rock dust will in some instances react with
ferric iron compounds but the pH is not high enough for it to react with
ferrous iron compounds.  Therefore, its neutralization potential is very
small and usually will not affect the discharge of acid water from
underground coal mines.


                   Underground Disposal of Acid Water

Recently, because of the attention surface waste disposal has received,
the use of porous underground strata for disposal sites has become attractive
to many industries.   The use of disposal wells for acid mine water by  the
coal industry in Pennsylvania was the object of a study conducted by
Pennsylvania State University, College of Mineral Industries, Department


                                   25

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of Mining.^9'50)  The study concluded that the use of disposal wells for
acid mine water is technically possible and the cost would probably
range from $0.20 to $0.75 per thousand gallons of disposed water.

Although the process is reported as feasible, opposition has been raised
by many state governments(->l,52) and the Environmental Protection Agency
of the Federal Government.  The basis for this opposition arose from
the results of experiments with deep well disposal systems at various
locations in the country.

One experiment^51) was undertaken by the United States Army at the Rocky
Mountain Arsenal, ten miles northeast of Denver.  The well was completed
in September, 1961, to a depth of 12,045 feet and the casing was cemented
in place to a depth of 11,975 feet to protect more shallow fresh water
aquifers.  A total of 165 million gallons of liquid waste was injected
into the well at an average rate of 200 gpm and 500 psi from March, 1962
till February, 1966.  Shortly after the disposal operation began, a series
of earthquakes were recorded in the Denver area and between April, 1962
and August, 1967, a total of 1,514 shallow depth earthquakes occurred.

Studies(53,54,55) macje of the incident have concluded that the earthquakes
were a product of reduced friction between layers of underground strata
and along fault zones set up by the injection of waste liquids into the
arsenal well.

An experiment^  ' that resulted in pollution of surface water was conducted
by the Hammermill Paper Company in Erie, Pennsylvania.  The waste liquids
were disposed of in a 1,610 foot well under pressures of up to 1300 psi
over a period of four years.  On April 14, 1968 the well top blew off
allowing two million gallons of the waste to flow into Lake Erie before
it was capped three weeks later.  Corrosion of a casing joint was given
as the reason for failure of the well.

An experimental drilling and disposal program was undertaken in southwestern
Pennsylvania with a test well at the No. 58 mine of the Bethlehem Mines
Corporation, a subsidiary of the Bethlehem Steel Corporation.  Cores of
the proposed area differed greatly in many aspects from those recorded
at three nearby gas wells.  The general lithplogy of the zone was quite
complex, but could be approximated and is shown in figure 12.  After
recording the logs, there was a general feeling that the well was not as
favorable as had been expected.  The sandstone in the proposed disposal
area was relatively thin and had a low porosity -

Although other factors also proved disadvantageous, it was felt that
in view of the investment, the project should proceed with fresh
water injection tests.  The experimental well ran into numerous other
difficulties and a decision to halt operations was finally reached when
the pumping pressure reached 2,000 psi to simulate an injection of 150
gallons of acid mine water per minute into the well.
                                 26

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    Depth From Surface (feet)               Rock Description

          1302 - 1314                     Shale
          1314 - 1365                     First Salt Sand*
          1365 - 1428                     Shale and Siltstone
          1428 - 1518                     Second Salt Sand**
          1518 - 1547                     Shale with Minor Coal
          1547 - 1565                     Maxton Sand***
          1565 - 1588                     Shale and Clays tone
  *Interbedded shale, siltstone, claystone and minor sandstone (16 feet)
 **Approximately 64 feet of sandstone with minor shale and siltstone.
***Entire interval sandstone.
   Fig. 12-General  Lithology  of Cored Interior of Disposal Well. (57)
Although Bethlehem's main purpose was to evaluate sub-surface disposal
as a means of abating acid mine pollution, the investigation was halted
before any acid mine water could be injected, and the amount of water
pumped into the zone was not sufficient to determine the long term effect
of this process. -Additional information about this project is available
through the Coal Research Board of Pennsylvania. (->6)

The lack of knowledge of the complex geologic structures underlying much
of the Appalachian coal fields and the potential pollutional effects that
could result from deep well injection is the chief concern of those state
and Federal agencies opposing this method of disposal of waste acid
drainage.
                                    27

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                               SECTION VI

                              MINE CLOSING

Mine closing methods should be carefully considered.   If not properly
sealed, an abandoned mine may continue to produce acid water.   Since
60 to 90 percent of the total acid discharged from all coal mines  is
from abandoned mines,(->°) some states require that provisions  for  seal-
ing be contained in the mining permit application.  Closing an operation
to prevent harmful mine drainage into nearby runs and streams  is  a
subject of much concern to states as a result of continuing problems
from long abandoned mines which were improperly closed.
                               Mine Seals

                    ( 59")
It has been reported*-  ' that abandoned mines sealed by natural cave-
ins produced less acid drainage than mines in the same locality that
remained open.  It was concluded that sealing of abandoned mines to
exclude air would help prevent stream pollution.

Determining whether the mine level is above or below the water table
will greatly influence the effectiveness of the seal.  It has been
observed("0) that effluents from mines above the water table do not
show as good a water quality as those taken from mines which are beloxj
the water table and are inundated.  One of the methods for abating pollution
in the thirties^  ' was construction of a large number of wet and dry seals.
Although the seals were of some aid, most have now deterioriated and overall
they have proved to be relatively ineffective.'"^'   It may be that the mines
were too close to the surface and they may have contained many voids,
faults, and subsidence holes which permitted air and water entry.
Deterioriation of the cement is another reason that many of the older
seals are now ineffective.

A typical wet seal consists ordinarily of concrete about 3 feet thick,
extending into the ribs approximately 3 feet, and set deep enough into
the floor to strike solid rock, which usually varies in depth from 18
to 36 inches.   '  The seals are generally flat or concave and have a
short section of pipe to release excess water pressure or provide
continual drainage.  A wet mine seal and its installation requirements
for a controlled flow are represented in figure 13.  The effectiveness
of sealing could be enhanced if the seals would be placed further back
in the opening where the surrounding rock would be stronger and therefore
better for anchoring the seal.

An in-depth study by the Halliburton Company for the EPA, which included
laboratory and field tests, was undertaken.  This study considered all
phases of mine sealing.(63)  one test examined the use of expendable
grout retainers (figure 14), which are collapsable fabric bags.  They
are placed in the entry and filled with a grout slurry.  The flexibility
of the bag eliminates the time for building concrete forms and also
                                    29

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OUTCROP
                             INTO FIRM ROCK
                    — PLA N-
                             NTO FIRM ROCK
                           • 1_—_^TV SHALE (ROOF)  -__^:
                              ACID RESISTANT  COATING
                                    TO  DESIGN HEIGHT a SIZE
                              ^_T-_T~ SHALE _n_n_r
               - ELEVATION-

 Fig. 13- Wet  Mine Seal  With  Controlled Flow.   (Handbook
          of Pollution Control Costs in Mint Drainage
          Management, F.W. RC.A.) (64)
                    30

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                                                                                   MINE OPENING
                                                                                   OR TUNNEL
                                                    EXPENDABLE GROUT RETAINERS
SAMPLING  OR
GROUTING TUBE
              FILLER SPOUTS
   Fig.  14-  Expendable Grout  Retainers.  (63)

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eliminates the requirement for personnel to enter the mine to prepare
the ribs, roof, and floor.  The retainers may also be permeable as a
means to permit a bond between the (a)  retainer fabric and surroundings
and (b)  successive retainers.

Another abatement method examined by Halliburton to close drift mine
openings involved using inflatable bags or packers located closely
adjacent to each other along an entry so as to provide pneumatic forms
between which grouting could be placed and permitted to harden to form
bulkheads.  Sealing is achieved when two sets of these bulkheads are
completed at sufficient distance from each other so as to permit intro-
duction of ample quantities of cement as a means to provide a substantial
plug.

The use of ground aggregate proved to be more feasible in areas where
the closeness of timbers and other permanent construction excluded the
use of expandable retainers.

Another investigation by Halliburton employed a plug consisting of
grouting as well as aggregate material of various grades or sizes
pneumatically discharged near the roof of a mine at the desired
location (see figure 15).  This plug was constructed as follows.   First,
the mine roof, floor, and ribs were cleared of extraneous material to
obtain a complete bond between the surface and the plug.  Second, a
bulkhead was deposited consisting of 3/4 to 1 1/2 inch graded limestone
30 feet back from the face of the opening.  The bulkhead extended from
wall to wall and from floor to roof, with a longitudinal base width
of approximately 14 feet and a top width of 2 feet.   Third, minus 3/8
inch aggregate was deposited on the face of the bulkhead to form a
barrier for the grout.  Fourth, 3/4 to 1 1/2 inch grouted aggregate
was then deposited in the center section.  Fifth, a layer of approximately
one foot of minus 3/8 inch aggregate was placed over this to form an
impermeable barrier.  Finally, twelve inches of 3/4 to 1 1/2 inch aggregate
was then deposited to form a protective cover and to bring the plug to its
final length of 34 feet.  Due to leakage of grout through the front and  rear
bulkheads, a flake cellophane material was added to the grout slurry
to act as a bridge in more permeable sections.  This proved to be effective
in stopping leakage.  Some drainage was also encountered from a bottom
pipe but could have been avoided had a quick-setting chemical been used
as a grouting agent.  It was concluded that this method could be used
to successfully close any drift mine opening without regard to posts
or other obstructions.
                               Inert Gas

The concept of using an inert gas to prevent oxidation of pyrite in
inactive coal mines has been known for many years.   Documentation exists
to show(°5) that a substantial reduction in the acid formed by pyrite
in contact with water can be obtained when the amount of oxygen in the
atmosphere is controlled, and that no acid is formed in an atmosphere
consisting of 100 percent nitrogen or another inert gas.  If the oxygen
could be reduced to 0.4 percent or lower,  the amount of acidity developed


                                    32

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                                    •j-"to l-j'Aqqregote    Minus |-"Aqqreqote
toly Aggregate
UJ
                    7'±
                                         AA J i
                                         (f£\kl«* ^ «••'••'v-.>l
                                         L'^J \»   »»•«.-;,> -- .^
                                                   •v-^fei-
                                                                       Grouted

                                                                   "X-5~
-------
by the water and pyrite could be reduced approximately 97 percent over
that occurring in air.

An inert gas atmosphere xrould be difficult to maintain due to the breath-
ing that results from changing barometric pressure.   A mine inhales  when
the barometric pressure is rising and will exhale as the pressure falls.
Supplying an inert atmosphere to a deep mine must therefore be at a  rate
high enough to keep up with the inhalation requirements associated with the
maximum rate of atmospheric pressure change.  The choice of atmosphere
is limited economically; nitrogen which costs approximately 60 cents per
1000 cubic feet would be very costly for even a small mine.  For this
reason alternative inert gas considerations led to the use of exhaust
gases from an internal combustion engine.

With support from the EPA, a program was begun by the Pennsylvania Department
of Mines and Mineral Industries to determine the applicability of introduc-
ing inert gas into abandoned deep mines.  Initial work to determine  major
leaks in abandoned mines has shown the leakage rate  is related to the
length of outcrop.  Although much work is involved in determining the
leakage rate of inert gas, the potential for water quality improvement
appears to more than offset this disadvantage.

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                              SECTION VII

                             UNIQUE METHODS

Ever since the problem of mine pollutant waters has been under considera-
tion, different mining methods have been investigated to abate the pollution
problem.

Two such methods which have been reported are inert gas operation and
revised mining methods.
                               Inert Gas

Under a grant from EPA, a program^65) has been initiated to determine the
applicability of an inert gas operation in an active deep coal mine.
Island Creek Coal Co., the grantee, is responsible for developing a
feasible mining method for mining coal in an inert atmosphere using
space age technology.

The mine, referred to as the "Buck Rogers Mine," is to be designed to allow
use of an all nitrogen, a nitrogen plus methane, or an all methane atmosphere,
The use of an inert atmosphere will permit the recovery of methane gas that
is released from the coal strata during mining operations.  A large gassy
mine is capable of producing up to 16 million cubic feet of methane a day.
The recovery of methane gas can enhance the economic feasibility of this
program.

There are many factors which are yet to be tested and many problems yet to
be solved in such an operation; the life support system, extraction and
transportation of coal, shafts and communication.  If the inert gas
mining method is perfected, and proves to be economical, it could solve
three basic problems associated with mining: (a) removal of all or most
of the oxygen to prevent fires and explosions, (b) prevention of oxidation
of pyrite to form acid water, and (c) removal of men from exposure
to dust, thus preventing miners pneumoconiosis.

It is anticipated that an experimental mine will go into production in
the mid-seventies at which time the feasibility of such an operation
will be determined.
                         Revised Mining Methods

Often it is possible to design a mine such that the workings advance to
the rise, giving an assist to haulage, drainage and sectionalizing
the location of the water.  A method in dipping seams is to work
room panels down dip from strike entries on advance, and up dip on
retreat.(66)  Hence, the dip areas are worked before extensive mining
occurs and such areas may be used as a primary or as a secondary sump
for gathering local water.
                                   35

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                              LIMESTONE
I.I  i. i~r
                                         SHALE
                         S ATY D STON E
                         •* ' • .1 '' \ ** •'' ' '.

                                           A 0 U I PER. •' '  '.
              '•.•: DEWATERING
                                                          LIMESTONE
                                    MINE
                                   ENTRY
       Fig. 16- Aquifer Dewatering System.
Another conceivable method^  ' to reduce water inflow which employs
hydrogeologic features involves the tapping of overhead aquifers and
draining of some of the water before it can seep into the mining
area.  The aquifer could conceivably be tapped from either the surface,
or in the mine, depending upon the depth of the coal seam and the aquifer.
If tapped from the mine, the water could be removed through a pipe system
to the outside or be retained for use in the mining operations.  Such  a
system is illustrated in figure 16.  If the aquifer is dewatered from
above, the pumping stations would be located on the surface which would
require additional capital investment and operating costs.

It is also possible to control extraction of coal in certain areas within
mines in .order to reduce infiltration of ground water.  Pillars and barriers
can be left in place if there is some possibility of intercepting large
volumes of water.  At outcrop lines and areas adjacent to worked out
inundated mines, the barriers should be of more than sufficient size to
keep water out while coal is being removed and to keep water in after
mining has been completed.' ''

Little engineering information is available to the mining engineer concern-
ing mining methods to prevent acid water formation.  Such information  would
be helpful in the mine planning stage where decisions are made as to
type of mining, size of pillars and type of equipment.  Most mining
textbooks, now obsolete, and handbooks consider only the problem of acid
                                   36

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water insofar as detrimental corrosion to pipes and pumps is concerned
since this subject represented the major acid water problem of a few
years ago.  However, nothing is mentioned on the critical subject of
water pollution from acid mine water.
                                     37

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                              SECTION VIII

                             RESEARCH NEEDS

This report was limited to a search of available literature on under-
ground methods to combat acid water pollution.  From this reviexj it
is evident that very little work has been done in this specific area.
It is also evident that there are specific areas of mining engineering
and mining related hydrology and geology that need further research efforts
to solve the many water problems.  They are:

(A)  Composition, variation and availability for oxidation
     of sulfur in strata.

(B)  Rate of oxidation of sulfuritic materials.

(C)  In situ limestone and its influence on underground
     acid drainage.

(D)  Structural, stratigraphic and hydrologic character of old
     mining areas as a basis to make decisions about adjacent new
     mining areas.

(E)  Operational changes in mining methods to prevent pollution.

(F)  Sealants for underground coating to exclude water from contact
     with pyrite to inhibit formation of the contaminants.  Such a
     program has been initiated on refuse piles.

The prime purpose of this report is to investigate those practices
which have been used to regulate or control water accumulation and
prevent harmful mine drainage.  A supplemental purpose is to indicate
those areas which need further research to prevent underground mine
water pollution.
                                   39

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                               SECTION IX

                             ACKNOWLEDGMENTS

The study reported herein was performed by the Coal Research  Bureau,
School of Mines, West Virginia University, via a grant  from the
Environmental Protection Agency.   Mr.  Joseph Leonard, Director,  Coal
Research Bureau, is the grant and project director for  the  contract.
The report was authored by Mr. Larry W. Wilson,  Mr.  Noah Matthews  and
Mr. James L. Stump.

Appreciation is due to Mr. Leonard G.  Nyland for his preliminary help in
gathering information for this report.  Grateful acknowledgment  is
also extended to Mr. Charles Cockrell, Assistant Director,  Coal
Research Bureau, for preliminary reading of this manuscript and  for
providing helpful suggestions.

Finally, the overall guidance provided by Mr. Ernst Hall and  Mr.
John J. Mulhern, the Grant Project Officer, is acknowledged with
sincere thanks.
                                      41

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                               SECTION X

                               REFERENCES

 1.   Eavenson,  H.  H.,  The First Century and A Quarter  of  the American
     Coal Industry, Waverly Press,  Baltimore,  Maryland,  (1942).

 2.   Forges, R., Van  Der Berg,  L.  A.  and Ballinger,  D. G.,  "Re-assessing
     an Old Problem,"  Journal of Sanitary  Engineering, pp 69-70  (February,
     1966) .

 3.   Braley, S. A., "Acid Drainage from Coal Mines," Mining Engineering,
     p 4 (August,  1951).

 4.   Kim, A. G., "An  Experimental Study of Ferrous Iron Oxidation in
     Acid Mine Water."  Presented Second Symposium on  Coal  Mine
     Drainage Research,  Mellon Institute,  Pittsburgh,  Pennslvania,
     pp 40-45 (May 14-15, 1968).

 5.   Stauffer,  T.  E.  and Louell, H. L., "The Oxidation of Iron II -
     Relationship to  Coal Mine Drainage Treatment,"  Pennsylvania
     State University Special Research Report SR-69  prepared for
     the Coal Research Board of the Commonwealth of  Pennsylvania;
     University Park,  Pennsylvania, November 1,  1968.

 6.   Biesecker, J. E.  and George,  J.  R., "Stream Quality  in Appalachia
     As Related to Coal Mine Drainage," U. S.  Geological Survey
     Circular 526, p  3 (1966)-

 7.   Hanna, George P-  and Brant, Russell A., "Stratigraphy  Relations to
     Acid Mine Water  Production."  Presented at  the  17th Annual Purdue
     Industrial Waste Conference,  Purdue University, West Lafayette,
     Indiana, May 3,  1962.

 8.   Davis, Stanley N. and DeWiest, R. J.  M.,  Hydrogeology, John Wiley
     and Sons,  Inc.,  New York,  New York, (1966).

 9.   Meinzer, Oscar E.,  "Outline of Ground-Water Hydrology," U. S.
     Geological Survey,  Water Supply Paper 494,  (1923).

10.   Kazmann, Raphael B., Modern Hydrology. Harper and Row, New York,
     New York,  (1965).

11.   Heath, Ralph C.  and Trainer,  Frank W., Introduction  to Ground-Water
     Hydrology, John Wiley and Sons,  Inc., New York, New York,  (1968).

12.   Linsley, Ray K.,  Jr.; Kohler, Max A.; and Paulhus, Joseph L. H.,
     Applied Hydrology,  McGraw-Hill,  Inc., New York, (1949).

13.   Sinclair,  John,  Water in Mines and Mine Pumps,  Sir Isaac Pitman and
     Sons, Ltd., London, (1958).
                                       43

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14.  Thompson,  D.  R.  and Emrich,  Crover H.,  "Hydrogeologic Considerations
     for Sealing Coal Mines,"  Pennsylvania Department of Health, Bureau
     of Sanitary Engineering Publication  23, pp 1-8  (August, 1969).

15.  McKinstry, Hugh  Exton, Mining  Geology,  Prentice - Hall, Inc., New
     York,  New  York,  pp 518-544  (1948).

16.  Simpson, Thomas  A., "Geologic  and Hydrologic Studies in the Birmingham
     Red-Iron-Ore District  of  Alabama," U. S. Geological Survey Professional
     Paper 47B-C,  (1965).

17.  Krickovic, Stephen, "Acid Mine Drainage Pollution Control-Approach
     to Solution," Mining Congress  Journal,  52, No.  12, pp 64-67
     (December, 1966).

18.  Jeffords,  R.  M., "Some Features of the  Mine-Water Problem in the
     Bituminous Coal  Mines," U.  S.  Geological Survey Open-File Report,
     (1948).

19.  Gallaher,  John T., "Geology, Hydrology  and Water Quality of the
     Combined Roaring Creek and  Grassy Run Watersheds, Randolph
     County West Virginia," unpublished U. S. Geological Survey
     report to  FWPCA  (now EPA).

20.  Ward,  Porter E.  and Wilmoth, Benton  M., "Ground-Water Hydrology of
     the Monongahela  River  Basin in West  Virginia,"  U. S. Geological
     Survey in  Cooperation  with  the West  Virginia Geological and Economic
     Survey, River Basin Bulletin 1, pp 13-18 (1968).

21.  Statham, I. C. F. , Coal-Mining, English University Press, Ltd,,
     London.

22.  Ash, S. H.; Dirks, H.  A.; and  Mitler, P. S., "Mine Flood Prevention
     and Control," U. S. Bureau  of  Mines  Bulletin 562, (1957).

23.  Hanna, George P-, Jr.  and others, "Acid Mine Drainage Research
     Potentialities," Journal  Water Pollution Control Federation,
     (March, 1963).

24.  Spencer, Edgar W., Geology:  A Survey of Earth  Sciences, Thomas Y.
     Crowell Co.,  New York, pp 330-335 (1965).

25.  Moebs, Noel N.,  "Mine  Air Sealing:   A Progress  Report," Second Symposium
     on Coal Mine Drainage  Research, Mellon  Institute, Pittsburgh, Pennsylvania,
     pp 255-264 (May, 1968).

26.  Jones, Donald G., and  Hunt,  Joseph W.,  Coal Mining, Volume II,
     Pennsylvania State University, State College, Pennyslvania,  (1949).

27.  Mason, E., Practical Coal Mining for Miners, Volume I, Virtue and
     Company, Ltd., Holborn, E.  C., London,  (1951).
                                      44

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28.  Emrich, Grover H., and Thompson, D.  R.,  "Some Characteristics  of
     Drainage from Deep Bituminous Mines  in Western Pennsylvania,"
     Second Symposium on Coal Mine Drainage Research,  Mellon Institute,
     Pittsburgh, Pennsylvania, pp 190-222 (May,  1968).

29.  Barnes, Ivan and Clarke, F.  E., "Geochemistry of  Ground Water  in
     Mine Drainage Problems," U.  S. Geological Survey  Professional
     Paper 473-A, (1964).

30.  Reidenour, David; Williams,  Eugene G. ; and Dutcher,  Russell R., "The
     Relationship between Paleotopography and Sulfur Distribution in
     Some Coals of Western Pennsylvania," Economic Geology,  62, (1967).

31.  Check, Robert, and Donaldson, Alan,  "Sulfur Facies of  the Upper
     Freeport Coal of North Western Preston County West Virginia,"
     Geological Society of America, Preconvention Field Trip Manual,
     West Virginia Geological and Economic  Survey,  pp 279-307
     (November, 1969).

32.  Hidalgo, Robert, "Sulfur-Clay Mineral  Relations in Coal," Geological
     Society of America, Preconvention Field  Trip Manual, West Virginia
     Geological and Economic Survey, pp 309-320  (November,  1969).

33.  Crichton, Andrew, B., "Disposal of Drainage from  Coal  Mines,"
     Transactions of the American Society of  Civil Engineers, 92,
     pp 1332-1337 (1928).

34.  Parizek, R., "Prevention of  Coal Mine  Drainage Problems by Well
     Dewatering," Paper presented at 1970 Society of Mining Engineers
     Meeting, St. Louis, Missouri, (October,  1970).

35.  Dierks, H. A., "Mine Water Problems  of the  Pennsylvania Anthracite
     Region," Mining Engineering, (October, 1957).

36.  Control of Acid Mine Drainage, Compiled  by  Coal Industry Advisory
     Committee, Ohio River Valley Water Sanitation Commission, Cincinnati,
     Ohio, (March, 1964).

37.  "Principles of Subsidence Engineering,"  National  Coal  Board, Production
     Department Information Bulletin 63/240,  (1963).

38.  McGlothlin, Charles, W., Jr., "Mining Hydrology of the Monongahela
     River Basin of West Virginia," unpublished  Masters Thesis, West
     Virginia University School of Mines, Morgantown, West  Virginia,
     (April, 1968).

39.  Holland, Charles T., "Some Aspects of  Stream Pollution Control from
     Acid Mine Drainage," Proceedings of  the  1968 West Virginia Coal Mining
     Institute, pp 190-203 (1968).

40.  "Mine Drainage and Acid Water Treatment," Coal Age,  pp 163-164
     (July, 1970).
                                    45

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41.  York, Lionel,  "Grouting by  Cementation," Mining Congress Journal,
     pp 51-55 (January,  1962).

42.  Cunningham,  L.  J.,  "The Use of  Chemicals in Mine Grouting," presented
     at 63rd Annual Meeting, Canadian Institute of Mining and Metallurgy>
     Quebec, p 8 (March, 1961).

43.  Ash, S. H.;  "Water  Problem  in the Pennsylvania Anthracite Mining
     Region," U.  S.  Bureau of Mines  Information Circular 7175, p 11
     (June, 1941).

44.  Lesser, William H., "Deep-Well  Pumps  and Shaft Pumps in Anthracite
     Mines of Pennsylvania," U.  S. Bureau  of Mines Report of Investigations
     4656, (March,  1950).

45.  Lorenz, Walter C.,  "Progress in Controlling Acid Mine Water:  A
     Literature Review," U.  S. Bureau of Mines Information Circular,
     (1962).

46.  Ash, S. H.,  and others, "Inundated Anthracite Reserves:  Eastern
     Middle Field of Pennsylvania,"  U. S.  Bureau of Mines Bulletin
     491, (1950).

47.  "Underground Coal Mining in the United States," TRW Systems Group,
     prepared for the Office of  Science and Technology.

48.  Walitt, Arthur; Jasinski, Raymond; and Keiln, Bertram, "Silicate
     Treatment of Coal Mine Refuse Piles," paper presented before
     Third Symposium on  Coal Mine Drainage Research, Mellon Institute,
     Pittsburgh,  Pennsylvania, p 180 (May, 1970).

49.  Stefanko, Robert; Linden, Karl  Vender; and Tilton, James G.,
     Subsurface Disposal of Acid Mine Water by Injection Wells,
     Pennsylvania State  University Special Research Report SR-52
     prepared for the Coal Research  Board  of the Commonwealth of
     Pennsylvania,  (August,  1965).

50.  Stefanko, Robert; Linden, Karl  Vender; and Tilton, James G.,
     "Potential Injection Well Strata for  Acid Mine Disposal in
     Pennsylvania," Pennsylvania State University Special Research
     Report SR-66 prepared for  the Coal Research Board of the
     Commonwealth of Pennsylvania, (October, 1967).

51.  Piper, Arthur M.,  "Disposal of  Liquid Wastes by Injection Underground-
     Neither Myth Nor Millennium," U. S. Geological Survey Circular 631,
     (1969).

52.  Cleary, Edward J.  and Warner, Don L., "Perspective on the Regulation
     of Underground Injection of Wastewaters," An appraisal sponsored by
     the Ohio River Valley Water Sanitation Commission December  1, 1969.

53.  Major, M. W.,  and Simon, R. B., "A Seismic Study of the Denver  (Derby)
     Earthquakes," Colorado School of Mines Quarterly, 63, No. 1,  (1968).
                                   46

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54.  Evans, D. M.,  "The Denver Area Earthquakes  and  the Rocky Mountain
     Arsenal Disposal Well," The Mountain Geologist,  63, No. 1,  (1966).

55.  Healy, J. W.  and others, "The Denver Earthquakes," Science, 161,
     No. 3848, (1968).

56.  Stefanko, Robert; Linden, Karl Vender;  and  Tilton, James G.,
     "Development and Testing of an Injection Well for the Subsurface
     Disposal of Acid Mine Water," Pennsylvania  State University Special
     Research Report SR-60 prepared for the  Coal Research Board of the
     Commonwealth of Pennsylvania, (February, 1967).

57.  Stefanko, Robert, Subsurface Disposal of Mine Water, Preprint No.
     69-AIME-10, Society of Mining Engineers of  AIME.

58.  Raleigh, Jr.,  "Acid Drainage Curbs Are  Here," Coal Age, 65, No. 4,
     pp 80-84 (April, 1960).

59.  Leitch, R. D., and Yant, W. P., "Sealing Old Workings," Coal Age, 35,
     No. 2, pp 78-80 (February, 1930).

60.  Braley, S. W. , "Acid Mine Drainage," reprint from Mechanization, 18,
     (1954).

61.  Braley, S. A., "An Evaluation of Mine Sealing,"  Coal Industry Advisory
     Committee to the Ohio River Valley Water Sanitation Commission,
     Research Project No. 370-8, (February,  1962).

62.  Braley, S. A., "Special Summary Report  on Mine  Acid Control," Common-
     wealth of Pennsylvania, Department of Health, Industrial Fellowship
     No. 326B-6, (August, 1952).

63.  "Feasibility Study on the Application of Various Grouting Agents
     Techniques and Methods to the Abatement of  Mine Drainage Pollution,"
     Halliburton Company prepared for Federal Water  Quality Administration,
     Parts 1, 2, 3 and 4, (May, 1968).

64.  "Handbook of Pollution Control Costs in Mine Drainage Management,"
     U. S. Department of Interior, FWPCA, (December,  1966).

65.  Rice, J. K., "The Use of Inert Gas to Eliminate Acid Production by
     Abandoned and Active Deep Mines,"   Third Symposium on Coal Mine
     Drainage Research, Mellon Institute, Pittsburgh, Pennsylvania,
     pp 169-180 (May, 1970).

66.  "Mine Drainage Methods and Water Handling Equipment," Coal Age,  71,
     No. 8, (August, 1966).

67.  Birch, Joseph J., "Application of  Mine  Drainage Control Methods,"
     Second Symposium on Coal Mine Drainage  Research, Mellon Institute,
     p 134  (May 14-15, 1968).
                                    47

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                               SECTION XI

                                GLOSSARY

Acid - A substance containing hydrogen which may be replaced by metals
       with the formation of salts.

Alkaline - Having the qualities of a base.

Aquifer - A formation, or a group of formations, that is water bearing
          and water transmitting.

Artesian - Refers to ground water under sufficient hydrostatic head
           to rise above the aquifer containing it.

Barrier Pillar - A solid block or rib of coal, etc.,  left unworked
                 between two collieries or mines for security against
                 accidents arising from an influx of water.

Borehole - A hole made with a drill, auger, or other tools for
           exploring strata in search of minerals, for water
           supply, for blasting purposes, for providing
           the position of old workings or faults, or for
           releasing accumulations of gas or water.

Contour - A line drawn through points of equal value on a map or
          diagram, most commonly points of equal elevation on a map.

Core Drill - A mechanism designed to rotate and cause an annular -
             shaped rock - cutting bit to penetrate rock formations,
             produce cylindrical cores of the formations penetrated,
             and lift such cores to the surface, where they may be
             collected and examined.

Dip - The angle at which a bed, stratum, or vein is inclined from
      the horizontal.

Gob Pile - A pile or heap of mine refuse on the surface.

Grouting - The act or process of injecting a coarse kind of plaster
           or cement into a crevice of a rock, usually through a
           borehole.

Hydrograph - A graph to show the level, flow, or velocity of water
             in a river or channel at all seasons of the year.

Hydrology - The science dealing with water standing or flowing on or
            beneath the surface of the earth.

Outcrop - The part of a rock formation that appears at the surface of
          the ground.  It includes those deposits that are so near to
          the surface as to be found easily by digging.
                                   49

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Overburden - Material of any nature,  consolidated or unconsolidated,  that
             overlies a deposit of useful materials,  ores  or coal.

Pyrite - Iron disulfide, FeS25 contains 46.7 percent iron,  53.3 percent
         sulfur.

Room and Pillar - A system of mining  in which the coal or  ore is mined
                  in rooms separated  by narrow ribs  or pillars.

Silica Gel - Porous material consisting of pure silicon dioxide. Used
             as a dehumidifying and a dehydrating agent.

Strike - The direction or bearing of  a horizontal line in  the plane of
         an inclined stratum that is  perpendicular to the  direction
         of the dip.

Subsidence - The lowering of the strata, including the surface,  due to
             underground excavat ions.

Topography - The physical features of a district or  region,  such as are
             represented on maps, taken collectively;  especially, the
             relief and contour of the land.
                                   50

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      Acce.xsion Number
                              Stibjecf Field & Group
                                                  SELECTED  WATER RESOURCES  ABSTRACTS
                                                        INPUT TRANSACTION FORM
      Organization


            Coal  Research Bureau, West Virginia University
      Title
              Underground Coal Mining Methods  to Abate  Water Pollution:
              Art  Literature Review
                                    A  State of the
   10
      Authors)
           Wilson,  Larry W.
           Matthews,  Noah J.
           Stump, James  L.
16
    Project Designation
21
              EPA Project No. 14010FKK
    Note
   22
       Citation
   23
       Descriptors (Starred First)
         *Acid Mine Water,  *Grouting Agents, *Hydrogeology,  *Water Management
   25
       Identifiers (Starred First)
       *Inert Gas, *Land  Management, *Silica Gel
   27
       Abstract
         This report is  a  review of published information  concerning the abatement of harmful
drainage from underground  coal mines.  Although much has been written on mine water
management, very little  literature is available on the specific  area of preventing the
formation of acid water.   The  references used in this report include mining engineering
and hydrology studies  and  spans the period of time when water quantity rather than quality
was the major consideration.

Physical approaches to the problem of interdicting water entry into  coal mines, beyond
removal and treatment, have only recently been undertaken.  Some new approaches to this
problem are (a) land management for surface and sub-surface water  diversion, (b) the
exploitation of water  carrying strata, and (c) new mining  methods.

Chemical approaches to abatement include (a)  the use of silica gel solutions underground
to prevent acid formation,  (b)  the use of inert gas in active mines  and (c) the use of
new and the refinement of  known grouting agents.
  Abstractor
                                 Institution
   WR: 102 (REV. JULY 1969)
   WRSI C
           SEND TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
                  U.S. DEPARTMENT OF THE INTERIOR
                  WASHINGTON, D. C. 20240
                                                                                  * GPO: 1969-359-339

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