EPA 440/1 -75/059d
Development Document for
Interim Final Effluent Limitations Guidelines
and New Source Performance Standards
for the
CLAY, CERAMIC, REFRACTORY
AND MISCELLANEOUS MINERALS
VOL. Ill
MINERAL MINING AND
PROCESSING INDUSTRY
Point Source Category
4fc
M(
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
OCTOBER 1975
-------
DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES
and
STANDARDS OF PERFORMANCE
MINERAL MINING AND PROCESSING INDUSTRY
VOLUME III
Clay, ceramic. Refractory and Miscellaneous Minerals
Russell E. Train
Administrator
Andrew W. Breidenbach, Pn.u.
Actina Assistant Administrator for
Water and Hazardous Materials
Eckardt C. Beck
Deputy Assistant Administrator for
Water Planning and Standards
Allen Cywin
Director, Effluent Guidelines Division
Michael W. Kosakowski
Project Officer
October 1975
Effluent Guidelines Division
Office Of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
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CONTENTS
Section
I Conclusions
II Recommendations 3
III Introduction 5
IV Industry Categorization 39
V Water Use and Waste. Characterization 43
VI Selection of Pollutant Parameters 121
VII Control and Treatment Technology 131
VIII Cost, Energy and Non-Water Quality Aspects 163
IX Effluent Reduction Attainable Through the 191
Application of the Best Practicable Control
Technology Currently Available
X Effluent Reduction Attainable Through the 205
Application of the Best Available Technology
Economically Achievable
XI New Source Performance Standards and Pretreatment 211
Standards
XII Acknowledgements 217
XIII References 219
XIV Glossary 221
ill
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LIST OF FIGURES
Figure_No. N
1 Supply-Demand Relationships for Clays - 1968 15
2 Supply-Demand Relationships for Feldspar - 1968 20
3 Production and Uses of Kyanite and Related 22
Minerals
t» Production and Uses of Talc Minerals 28
5 Domestic Consumption of Diatomite 34
6 fapply-Demand Relationships for Graphite -1968 37
7 Bentonite Mining and Processing 47
8 Fire clay Mining and Processing 50
9 Attapulgite Mining and Processing 53
10 Montmorillonite Mining and Processing 56
11 Kaolin (dry) Mining and Processing 59
12 Kaolin (wet) Mining and Processing 61
13 Ball Clay Mining and Processing 65
14 Feldspar (wet) Mining and Processing 69
15 Feldspar (dry) Mining and Processing 75
16 Kyanite Mining and Processing 77
17 Magnesite Mining and Processing 81
18 Shale Mining and Processing 84
19 Aplite Mining and Processing 86
20 Talc (dry) Mining and Processing 90
21 Talc (log washing) Mining and Processing 92
22 Talc (wet screening) Mining and Processing 93
23 Talc (flotation) Mining and Processing 96
24 Talc (impure ore) Mining and Processing 98
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25 Pyrophyllite (heavy media) Mining and Processing 99
26 Garnet Mining and Processing 103
27 Tripoli Mining and Processing 107
28 Diatomite Mining and Processing 109
29 Graphite Mining and Processing 113
30 Jade Mining and Processing 117
31 Novaculite Mining and Processing 119
Yi
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LIST OF TABLES
Table_No.
1 Recommended Limitations for the Clay, 4
Ceramic, Refractory, and Miscellaneous
Minerals Segment of the Mineral Mining
and Processing Industry
2 Data Base 9
3 1972 Production and Employment Figures 14
for Minerals in this Segment
H Industry Categorization 41
5 Settling Characteristics of Suspended 134
Solids
6 Comments on Treatment Technologies used 160
in this Industry
i*
7 Present Capital Investment and Energy 165
Consumption of Wastewater Treatment
Facilities
8 Cost for Representative 171
Attapulgite Facility
9 Cost for Representative 172
Montmorillonite Facility
10 Cost for Representative 173
Montmorillonite Mine Water
11 Cost for Representative 176
wet Process Kaolin Facility
12 Cost for Representative 177
Ball Clay Facility
13 Cost for Representative 180
Wet Process Feldspar Facility
14 Cost for Representative 183
Kyanite Facility
15 Cost for Representative 187
Wet Process Talc Minerals Facility
16 Conversion Table 228
vii
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SECTION I
CONCLUSIONS
For purposes of establishing effluent limitations guidelines
and standards of performance, and for ease of presentation,
the mineral mining industry has been divided into .three
segments to be published in three volumes: minerals for the
construction industry: minerals for the chemical and
fertilizer industries; and clay, ceramic, refractory and
miscellaneous minerals. This division reflects the end use
of the mineral after mining and beneficiation. In this
volume covering clay, ceramic, refractory, and miscellaneous
minerals, the 21 minerals are grouped into 17 production
subcategories for reasons explained in Section IV.
Based on the application of best practicable technology
currently available, 11 of the 17 production subcategories
under study can be operated with no discharge of process
generated waste water pollutants to navigable waters. With
the best available technology economically achievable, 12 of
the 17 production subcategories can be operated with no
discharge of process generated waste water pollutants to
navigable waters. No discharge of process generated waste
water pollutants to navigable waters is achievable as a new
source performance standard for all production subcategories
except kaolin (wet) , feldspar (wet) , talc minerals
(flotation), garnet, and graphite. Mine drainage and
contaminated plant runoff are considered separately for each
subcategory.
This study included 21 clay, ceramic, and refractory
minerals of Standard Industrial Classification (SIC)
categories 1452, 1453, 1454, 1459, 1496, and 1499 with
significant waste discharge potential as listed below with
the corresponding SIC code.
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1. Berrtonite (1452)
2. Fire Clay (1453)
3. Fuller's Earth
A. Attapulgite
B. Montmorillonite
4. Kaolin and Ball Clay (1455)
5. Feldspar {1459}
6. Kyanite (1459)
7. Magnesite (Naturally Occurring) (1459)
8. Shale and other Clay Minerals (1459)
A. Shale
B, Aplite
9. Talc, Soapstone, Pyrophyllite, and Steatite (1496)
10. Natural Abrasives (1499)
A. Garnet
B, Tripoli
11. Diatomite (1499)
12. Graphite (1499)
13. Miscellaneous Non Metallic Minerals (1499)
A. Jade
B. Novaculite
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SECTION II
RECOMMENDATIONS
The recommended effluent limitations guidelines and the
suggested technologies are listed in Table 1. pH should be
maintained between 6.0 and 9.0 units at all times.
The pretreatment limitations will not limit total suspended
solids, unless there is a problem of sewer plugging, in
which case 40 CFR 128.131 (c) applies. Limitations for
parameters other than TSS are recommended to be the same for
existing sources as best practicable control technology
currently available and for new sources as new source
performance standards.
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RecDtnniui.dcxl Limits and RtutuUirds for the- Mineral Mlnir.f, raid rroccBtitm* Jr.
The following apply to process wnstt* water except where no'ed
Subcategory
Unntonite,
FJro clay,
MontKorillonite ,
Att.ipulglte
Kyanlcc,
Mnr,iic-sitc,
Shale.,
ApHte,
Tripo) J (dry procrsfslns) ,
Matoinit",
Jnde 6,
Kovnculite
Mine drainage
(non-Reid)
Mine drainage
(acid)
Kaolin
Dry processing
W(?t processing
Mine drainage
(ore £lm L'y pulped)
Mini; drainage
(oia dry transporter
Ball Clay
Dry processing
Vet processing
Hir.e drainage
(non-acid)
Mine dralnngn
(acid)
Feldnpar
BPCTCA
nax. ftvg, of 30
consecutive days
No difjchrt
TSS 35 tsg/1
Els Fe 0.3 mg/1
No dlscha
Turbidity 50 JTU
TSS 45 \> /I
Zn 0.25 r,»c/l
Turbidity 50 JTU
TSS 45 mg/1
a;
Ho discli.".
TSS 0,17 ku/kkg
TSS 35 tsg/l
Die FE 0.3 icg/;.
max. for
cny oue day
rge
TSS 35 rag/1**
,
TSS 70 mg/1
Dis Fe 0.6 ran/1
rp,c
Turbidity ICO JTU
TSS 90 mg/1
Zn 0.5C Kg/1
Turl>ldtf.y 100 JTU
TSS 90 RIR/]
TSS 35 mg/1
I'RO
TbS 0.34 kg/tskf;
TSS 35 ng/1
TSS 70 ir.g/1
131s Fe 0,6 tne/1
tiun-Flotu.'.ion (/iaiitd No dischnvge
Flotation pltitts*
Mine drainage
TSS 0,6 kfj'fkf.
f 0.175 kg/kkg
TSS 1.2 kg/V-kj;
F 0,33 kg/UkR
TSS 35 rag/1
BATLA and "iSfS
ffiax. avg. oi 30 Rtax. for
conseculivd days flity O:;K day
No discharge
TSS 35 mg/I
TSS 35 mg /I TSS 70 !"g/l
Bis Fe 0,3 mg/1 Ills "c 0.6 mg/1
Ho discharge
Turbid'lly 50 JTU Turbidity 100 JTli
1SS 45 KB/1 TSS 90 r;g/l
7,n 0,25 nig/1 'S.a. 0,50 raf»/l
Turbidity 50 JIV Turtldlty IOC JTU
TSS 45 1.13/1 TSS 90 mg/1
TSS 35 rag/!
Ro discharge
No dischnrgo
TSS 35 mg/1
TES 35 rrg/1 TSS 70 pg/1
Dig l"e 0.3 ug/1 Dis Fc 0.6 mg/1
No discharge
TSS 0,6 kn/k".;g TSS 1,2 kg/kkg
F 0,13 kc/kl;g F 0,26 kg/kkf,
TSS 35 tag/1
T«lc, Steatite, Soapstono and PyrojihylHte
Dry processing &
Washing plants
Flotation and HMS
plants
Hine drainage
Garnet
HiUE drainage
Graphite (process and
mine drainage
No discharge
TSS 0.3 kg/J;kg
TSS 0.4 kfi/kkg
TSS 10 r,ig/l
Total Fe 1 tng/1
TSS 1.0 fcg/kkg
TSS 35 mg/1
TSS 0.8 kg/kkg
TSS 35 mg/1
TSS 20 mg/1
Tftal Fe 2 tn^/l
rSS 0.3 kfc/kkg 7SS 0.6 kg/kkg
TSS 35 ui[',/l
TSS 0.25 kg/kkg TSS -0.5 kg/kkg'
TSS 35 tag/1
TSS 10 Blg/1 TSS 20 ir.g/1
Total Fe 1 mg/1 Total Fe 2 mg/1
pH 6-9 £ar all subc
Ko diurluii'^t: ^ )lc> discht'trgi' of procrris waste water pollutants
kfj/kl'fi - kf, of polJ-iJt,-int /I'.kg of prorlwcc
*kp of |jOllutant/ki:^ of ore processed
BPCTCA - Bent practJcfiblc control fcchnolojjy curiently availoblc
BATEA •• Btst available technology octnonically Achievable
NSl'S - Nov source i»cu-fn! trance sLcinclard.
Dla - UJasolvcd
**Ho TSS limit (HPCTtA) vecorJncndod for ir.ontmorillon.ttc Bine
«t this eime.
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SECTION III
INTRODUCTION
PURPOSE AND AUTHORITY
The United States Environmental Protection Agency (EPA) is
charged under the Federal Water Pollution Control Act
Amendments of 1972 with establishing effluent limitations
which must be achieved by point sources of discharge into
the navigable water of the United States.
Section 301(b) of the Act requires the achievement by not
later than July 1, 1977, of effluent limitations for point
sources, other than publicly owned treatment works, which
are based on the application of the best practicable control
technology currently available as defined by the
Administrator pursuant to Section 301(b) of the Act.
Section 301(b) also requires the achievement by not later
than July 1, 1983, of effluent limitations for point
sources, other than publicly owned treatment works, which
are based on the application of the best available
technology economically achievable which will result in
reasonable further progress toward the national goal of
eliminating the discharge of all pollutants, as determined
in accordance with regulations issued by the Administrator
pursuant to Section 304 (b) to the Act. Section 306 of the
Act requires the achievement by new sources of a Federal
standard of performance providing for the control of the
discharge of pollutants which reflects the greatest degree
of effluent reduction which the Administrator determines to
be achievable through the application of the best available
demonstrated control technology, processes, operating
methods, or other alternatives, including, where
practicable, a standard permitting no discharge of
pollutants. Section 304 (b) of the Act requires the
Administrator to publish within one year of enactment of the
Act, regulations providing guidelines for effluent
limitations setting forth the degree of effluent reduction
attainable through the application of the best practicable
control technology currently available and the degree of
effluent reduction attainable through the application of the
best control measures and practices achievable including
treatment techniques, process and procedure innovations,
operation methods and other alternatives. The regulations
proposed herein set forth effluent limitations guidelines
pursuant to Section 304(b) of the Act for the clay, ceramic,
refractory and miscellaneous minerals segment of the mineral
mining and processing industry point source category.
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Section 306 of the Act requires the Administrator, within
one year after a category of sources is included in a list
published pursuant to Section 306 (b) (1) (A) of the Act, to
propose regulations establishing Federal standards of
performances for new sources within such categories. The
Administration published in the Federal Register of January
16, 1973 (38 F.R. 1624), a list of 27 source categories.
Publication of an amended list will constitute announcement
of the Administrator's intention of establishing, under
Section 306, standards of performance applicable to new
sources within the mineral mining and processing industry.
The list will be amended when proposed regulations for the
mineral mining and processing industry are published in the
§£§i Register.
SUMMARY OF METHODS
The effluent limitations guidelines and standards of per-
formance proposed herein were developed in a series of sys-
tematic tasks. The Mineral Mining and Processing Industry
was first studied to determine whether separate limitations
and standards are appropriate for different segments within
a point source category. Development of reasonable industry
categories and subcategories, and establishment of effluent
guidelines and treatment standards requires a sound
understanding and knowledge of the mineral mining and
processing industry, the processes involved, waste water
generation and characteristics, and capabilities of existing
control and treatment methods.
This report describes the results obtained from application
of the above approach to the mining of clay, ceramic,
refractory, and miscellaneous minerals segment of the
mineral mining and processing industry. Thus, the survey
and testing covered a wide range of processes, products, and
types of wastes.
The products covered in this report are listed below with
their Sic designations:
a. Bentonite (1452)
b. Fire Clay (1453)
c. Fuller's Earth (1454)
d. Kaolin and Ball Clay (1455)
e. Feldspar (1459)
f. Kyanite (1459)
g. Magnesite (1459)
h. Shale and other clay minerals, N.E.C. (1459)
i. Talc, Soapstone and Pyrophyllite (1496)
j. Natural abrasives (1499)
k. Diatomite mining (1499)
1. Graphite (1499)
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m. Miscellaneous Non-metallic minerals,
N.E.C. (1499)
Any of the above minerals which are processed only (3295)
are also included.
categorization and Waste Load Characterization
The effluent limitation guidelines and standards of perform-
ance proposed herein were developed in the following manner.
The point source category was first categorized for the
purpose of determining whether separate limitations and
standards are appropriate for different segments within a
point source category. Such subcategorization was based
upon raw material used, product produced, manufacturing
process employed, and other factors. The raw wastes
characteristics for each subcategory were then identified.
This included an analysis of (1) the source and volume of
water used in the process employed and the sources of waste
and waste waters in the facility; and (2) the constituents
of all waste waters including harmful constituents and other
constituents which result in degradation of the receiving
water. The pollutants of waste waters which should be
subject to effluent limitations guidelines and standards of
performance were identified.
Treatment and Control Technologies
The full range of control and treatment technologies
existing within each subcategory was identified. This
included an identification of each control and treatment
technology, including both in facility and end of process
technologies, which are existent or capable of being
designed for each subcategory. It also included an
identification of the amount of pollutants (including
thermal) and the characteristics of pollutants resulting
from the application of each of the treatment and control
technologies. The problems, limitations and reliability of
each treatment and control technology were also identified.
In addition, the non water quality environmental impact,
such as the effects of the application of such technologies
upon other pollution problems, including air, solid waste,
noise and radiation were also identified. The energy
requirements of each of the control and treatment
technologies were identified as well as the cost of the
application of such technologies.
Data Base
The data for identification and analyses were derived from a
number of sources. These sources included EPA research
information, published literature, qualified technical
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consultation, on site visits and interviews at numerous
mining and processing facilities throughout the U.S.,
interviews and meetings with various trade associations, and
interviews and meetings with various regional offices of the
EPA. All references used in developing the guidelines for
effluent limitations and standards of performance for new
sources reported herein are included in Section XIII of this
report. Table 2 summarizes the data base for the various
subcategories sutdied in this volume.
Facility Selection
The following selection criteria were developed and used for
the selection of facilities.
Qischajrcje ef flU§Qt_ quantities
Facilities with low effluent quantities or the ultimate of
no discharge of process waste water pollutants were
preferred. This minimal discharge may be due to reuse of
water, raw material recovery and recycling, or to use of
evaporation. The significant criterion was minimal waste
added to effluent streams per weight of product
manufactured. The amounts of wastes considered here were
those added to waters taken into the facility and then
discharged. If different processes are used by industry to
achieve this low level of pollution further
subcategorization was considered.
The efficiency of land use was considered.
Air E2llutipn and solid waste control
Exemplary facilities must possess overall effective air and
solid waste pollution control where relevant in addition to
water pollution control technology. Care was taken to
insure that all facilities chosen have minimal discharges
into the environment and that these sites do not exchange
one form of pollution for another of the same or greater
magnitude.
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TABLE 2
DATA BASE
Subcategory
Bentonite
Fire Clay
Fuller's
Earth
At-tapulgite
Montmor.
Kaolin Dry
Kaolin Wet
Ball Clay
Feldspar
Wet
Dry
Kyanite
Magnesite
Shale and
Common Clay
Aplite
Talc Minerals
Dry
Washing
HMS,
Flotation
Natural Abrasives
Garnet
Tripoli
Diatomite
Graphite
Misc. Minerals
Jade
Novaculite
No. Plants
37
81
10
4
37 total
12
5
2
129
2
27
2
3
4
Q
1
No. Plants
Data
Visited Available
2
9
est,
1
10
2
2
3
1
1
1
2
9
4
O
J
4
6
4
5
2
2
1
10
2
12
1
5
3
4
7
4
5
2
o
1
20
2
20
2
2
4
3
1
1
1
Verification
Sampling
*
*
2
3
*
0
0
5
*
*
*
0
*
*
0
*
A
Total
est. 384
70
94
15
*There is no discharge of process waste water in the subcategories
under normal operating conditions.
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Effluent -treatment methods a.n.d their effect ivgn.es.s
The facilities selected have in use the best currently
available treatment methods, operating controls, and
operational reliability; Treatment methods considered
included basic process modifications which significantly
reduce effluent loads as well as conventional treatment
methods.
Facility, facilities
All facilities chosen had all the facilities normally
associated with the production of the specific product (s) in
question. Typical facilities generally were facilities
which have all their normal process steps carried out on
site,
Facility maQageinegt philosophy
Facilities were preferred whose management insists upon
effective equipment maintenance and good housekeeping
practices. These qualities are best identified by a high
operational factor and facility cleanliness,
Geographic location
Factors which were considered include facilities operating
in close proximity to sensitive vegetation or in densely
populated areas, other factors such as land availability,
rainfall, and differences in state and local standards were
also considered in so far as those locations with strict
standards usually result in exemplary facility performance.
Raw materials
Differences in raw materials purities were given strong con-
sideration in cases where the amounts of wastes are strongly
influenced by the purity of raw materials used. Several
facilities using different grades of raw materials were
considered for those minerals for which raw material purity
is a determining factor in waste control.
o£ processes
On the basis that all of the above criteria are met,
consideration was given to installations having a
multiplicity of manufacturing processes. However, for
sampling purposes, the complex facilities chosen were those
for which the wastes could be clearly traced through the
various treatment steps.
10
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Production
On the basis that other criteria are equal, consideration
was given to the degree of production rate scheduled on
water pollution sensitive equipment.
Product purity
For cases in which purity requirements play a major role in
determining the amounts of wastes to be treated and the
degree of water recycling possible, different product grades
were considered for subcategorization.
GENERAL DESCRIPTION OF INDUSTRY BY PRODUCT
Clays and other ceramic and refractory materials differ
primarily because of varying crystal structure, presence of
significant non-clay materials, variable rations of alumina
and silica, and variable degrees of hydration and hardness.
This industry, together with ore mining and coal mining,
differs significantly from the process industries for which
effluent limitation guidelines have previously been
developed. The industry is characterized by an extremely
variable raw waste load, depending almost entirely upon the
characteristics of the natural deposit. The prevalent
pollutant poblem is suspended solids, which vary
significantly in quantity and treatability.
For the purpose of this section we will define clay as a
naturally occurring, fine-grained material whose composition
is based on one or more clay minerals and contains
impurities. The basic formula is A12O3SiO3.xH2O. Important
impurities are iron, calcium, magnesium, potassium, and
sodium which can either be located interstitially in the
hydrous aluminum silicate matrix or can replace elements in
the clay minerals. As it may be imagined there is a
infinite mixture of clay minerals and impurities, and a
solution for nomenclature would seem insurmountable. The
problem is solved somewhat haphazardly by classifying a clay
according to its principal clay mineral (kaolin-kaolinite),
by its commercial use (fire clay and fullerfs earth) or by
its properties (plastic clay). Much clay, however, is
called just common clay. Some of the principal clay
minerals are kaolinite, montmorillonite, attapulgite, and
illite.
Kaolinite consists of alternating layers of silica
tetrahedral sheets and alumina octahedral sheets.
Imperfections and differences in orientation within this
stacking will lead to differences in the kaolinite mineral.
Each unit within the montmorillonite stack is composed of
two silica tetrahedral sheets sandwiching a alumina
11
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octaheldral sheet. Because of the unbalanced forces between
sucessive units, polar molecules such as water can enter
and distribute the changes. This accounts for the swelling
properties of montmorillonite bearing clays. The presence
of sodium, calcium, magnesium and iron between units will
also affect the degree of swelling.
The unit structure of attapulgite is comprised of two silica
chains liked by octahedral groups of hydroxyls and oxygens
containing aluminum and magnesium. The emperical formula is
(Mg,Al)5 SiBQ2
The unit structure of illite resembles that of
montmorillonite except that aluminum ions replace some of
the silicon ions. The resultant charge imbalance is
neutralized by the inclusion of potassium ions between
units.
Most clays are mined from open pits, using modern surface
mining equipment such as draglines, power shovels, scraper
loaders, and shale planers. A few clay pits are operated
using crude hand mining methods. A small number of clay
mines (principally underclays in coal mining areas) are
underground operations employing mechanized room and pillar
methods. Truck haulage from the pits to processing
facilities is most common, but other methods involve use of
rail transport, conveyor belts, and pipelines in the case of
kaolin. Recovery is near 100 percent of the minable beds in
open pit mines, and perhaps 75 percent in the underground
operations. The waste to clay ratio is highest for kaolin
(about 7:1) and lowest for miscellaneous clay (about
0.25:1) .
Processing of clays ranges from very simple and inexpensive
crushing and screening for some common clays to very
elaborate and expensive methods necessary to produce paper
coating clays and high quality filler clays for use in
rubber, paint, and other products. Waste material from
processing consists mostly of quartz, mica, feldspar, and
iron minerals.
Clays are classified into six groups by the Bureau of Mines,
kaolin, ball clay, fire clay, bentonite, fuller's earth, and
miscellaneous clay. Halloysite is included under kaolin in
Bureau of Mines statistical reports. Specifications of
clays are based on the method of preparation (crude, air
separated, water washed, delaminated, air dried, spray
dried, calcined, slip, pulp, slurry, or water suspension) ,
in addition to specific physical and chemical properties.
12
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The 1972 production and employment figures for the clay,
ceramic, refractory and miscellaneous minerals industries
were derived either from the Bureau of the Census (U.S.
Department of Commerce) publications or the Commodity Data
Summaries (1974) Appendix I to Mining and Minerals Policy,
Bureau of Mines, U.S. Department of the Interior. These
figures are tabulated in Table 3.
BENTONITE (SIC 1452)
Bentonites are fine-grained clays containing at least 85
percent montmorillonite. The swelling type has a high
sodium ion concentration which causes a material increase in
volume when the clay is wetted with water, whereas the
nonswelling types usually contain high calcium ion
concentrations. Standard grades of swelling bentonite
increase from 15 to 20 times their dry volume on exposure to
water. Specifications are based on pertinent physical and
chemical tests, particularly those relating to particle size
and swelling index. Bentonite clays are processed using the
following processes: weathering, drying, grinding, sizing,
and granulation. The supply-demand relationships for
bentonite and other clays for 1968 are shown in Figure 1.
The principal uses of bentonites are drilling muds, catalyst
manufacture, decolorizing agents, and foundry use. However
the properties within the bentonite group vary such that a
single deposit cannot serve all the above mentioned
functions. Because of the high montmoillonite content
bentonites are an important raw material in producing
fuller's earth. The distinction between these two clays is
not clearly defined except by end usage.
The bentonites found in the United states were deposited in
the Cretaceous age as fine air-borne volcanic ash.
Advancing salt water seas and groundwater had resulted in
cationic exchangead addition of iron and magnesium. The
placement of the relatively large sodium and calcium ions
between the silica and alumina sheets in the basic
montimorillonite lattice structure are responsible for the
important property of swelling in water. Sodium bentonite
is principally mines in Wyoming while calcium bentonite is
found in many states, but principally Texas, Mississippi and
Arizona.
FIRE CLAY (SIC 1453)
The terms "fire clays" and "stoneware clays" are based on
refractoriness or on the intended usage (fire clay
indicating potential use for refractories (hence they are
also called refratory clays), and stoneware clay indicating
use for such items as crocks, jugs, and jars). Their most
13
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TABLE 3
1972 U.S. Production and Employment Figures For Clay,
Ceramic, Refractory, and Miscellaneous Minerals
1452
1455
1455
1459
1459
1459
1459
1459
1496
1496
1496
1499
1499
1499
1499
1499
* includes
Product
Bentonite
Fire clay
Fuller's
Earth
Kaolin
Ball clay
Feldspar
Kyanite
Magnesite
Aplite
Crude common
Clay
Talc
Soapstone
Pyrophyllite
Abrasives
Garnet
Tripoli
Diatomite
Graphite
Jade
Novaculite
ball clay
Production
kkq L (tgnglL
2,150,000
(2,767,000)
3,250,000
(3,581,000)
896,000
(988,000)
4,810,000
(5,318,000)
612,000
(675,000)
664,000
(732,000)
Est. 108,000
(Est. 120,000)
Withheld
190,000
(210,000)
41,840,000
(46,127,000)
1,004,000
17,200
(19,000)
80,000
(88,000)
522,000
(576,000)
Withheld
107
(118)
Withheld
Employinent
900
500
1,200
3,900*
450
165
Unknown
Unknown
2,600
950
Unknown
Unknown
500
54
Unknown
15
14
-------
WORLD PRODUCTION
«/ 350.000
KEY
Unitf. Thoujona short lonj
J/ e«llmol»
S|C Standard tnduilrlal Clo >n Itcs'io
U.S. Kippl j , J.S.iOfnom)
37,529 33,810
Enpor;»
I.SZO
Iron and sti«f
I (.125
I Gloit
2 (~1 tf't^if-Jiiit
.u i I <7T
Paper
I FOOA- »oni3s
6 SO
iron cfe
Isictollf
410
J
OlftBf
1,714
Figure 1. Supply-Demand Relationships for Clays, 1968.
-------
notable property is their high fusion points. Fire clays
are principally kaolinitic containing other clay minerals
and impurities such as quartz. Included under the general
term fire clay are the diaspore, burley, and hurley flint
clays. Fire clays are usually plastic in nature and are
often referred to as plastic clays, but flint clays are
exceedingly hard due to their high content of kaolinite.
The fired colors of fire clays range from reds to buffs and
grays. Specifications are based on pertinent physical and
chemical tests of the clays, and of products made from them.
In general the higher the alumina content the higher the
fusion point. Impurities such as lime and iron lower the
fusion point. Fire clays are mined principally in Missouri,
Illinois, Indiana, Kentucky, Ohio, West Virginia,
Pennsylvania and Maryland. The fire clays are processed by
crushing, calcining and final blending.
FULLER'S EARTH (SIC 1U54)
The term "fuller's earth" is derived from the first major
use of the material, which was for cleaning wool by fullers.
Fuller's earths are essentially montmorillonite or
attapulgite for which the specifications are based on the
physical and chemical tests of the products. As previously
mentioned the distinction between fuller's earth and
bentonite is in the commercial usage. Major uses are for
decolorizing oils, edible fluids, and cat litter. The
fuller's earth clays are processed by blunging, extruding,
drying, crushing, grinding and finally sizing according to
the requirements of its eventual use.
KAOLIN AND BALL CLAY (SIC 1455)
Kaolin is the name applied to the broad class of clays
chiefly comprised of the mineral kaolinite. Although the
various kaolin clays do differ in chemical and physical
properties the main reason for distinction has been
commercial usage. Both fire clay and ball clay are kaolin
clays. That portion of the kaolin clays term kaolin is
mined in South Carolina and Georgia and is used as fillers
and pigments. Ball clays consist principally of kaolinite,
but have a higher silica to alumina ratio than is found in
most kaolins in addition to larger quantities of mineral
impurities, the presence of minor quantities of
montmorillonite and, often, much organic material. They are
usually much finer grained than kaolins due to their
sedimentary origin and, in general set the standards for
plasticity of clays. Ball clays are mined in western
Kentucky, western Tennessee and New Jersey. Specifications
for ball clays are based on methods of preparation (crude,
shredded, air floated) and pertinent physical and chemical
16
-------
tests, which are much the same as those for kaolin. The
prinicpal use for ball clay is in whitewares (e.g. china).
MISCELLANEOUS CLAYS
The last Bureau of Mines category of clays, is the
miscellaneous clay category. Miscellaneous clay may contain
some kaolinite and montmorillonite, but usually illite
predominates, particularly in the shales. There are no
specific recognized grades based on preparation, and very
little based on usage, although such a clay may sometimes be
referred to as common, brick, sewer pipe, or tile clay.
Specifications are based on the physical and chemical tests
of the products.
Most of the environmental disturbance related to clay mining
and processing is concerned with miscellaneous clays, which
are used mostly for making heavy clay construction products,
lightweight aggregates, and cement. The environmental
considerations are significant, not because the waste
products from clay mining are particularly offensive, but
because of the large number of operations and the necessity
for locating them in or near heavily populated consumption
centers. The principal environmental factors involved are
dust, noise, and unsightly or incongruous appearance.
Inadequate long range area planning has often contributed to
the environmental disturbance in the past, but the growing
awareness of the need for orderly development of area
resources should result in improvements in the future.
Environmental disturbances in kaolin mining and processing
are of major concern in central Georgia, where most of the
high quality filler grades are produced. Although the clay
mining for the most part is not in areas of high population
density, the mined areas are extensive, and large amounts of
materials are generated. On occasion, flash floods may dump
significant quantities of clay wastes into local streams,
and although the wastes are not reactive, temporary
overloading of the streams might be harmful to some types of
marine life. Steps are being taken to alleviate the
undesirable conditions by rapid rehabilitation of mined
areas and by using the waste materials as fill.
FELDSPAR (SIC 1459)
Feldspar is a general term used to designate a group of
closely related minerals, especially abundant in igneous
rocks and consisting essentially of aluminum silicates in
combination with varying proportions of potassium, sodium,
and calcium. The feldspars are the most abundant minerals
in the crust of the earth. The principal feldspar species
17
-------
are orthoclase or microcline (both K20«A12O3«6siO2) , albite
(Na20«Al£03«6Si02), and anorthite (CaO«Al2O3«2SiO2).
Specimens of feldspar closely approaching the ideal
compositions are seldom encountered in nature, however, and
nearly all potash feldspars contain significant proportions
of soda. Albite and anorthite are really the theoretical
end members of a continuous compositional series known as
the plagioclase feldspars, none of which, moreover, is
ordinarily without at least a minor amount of potash.
originally, only the high potash feldspars were regarded as
desirable for most industrial purposes. At present,
however, in many applications the potash and the soda
varieties, as well as mixtures of the two, are considered to
be about equally acceptable. Perthite is the name given to
material consisting of orthoclase or microcline, the
crystals of which are intergrown to a variable degree with
crystals of albite. Most of the feldspar of commerce can be
classified correctly as perthite. Anorthite and the
plagioclase feldspars are of limited commercial importance.
Until a few decades ago virtually all the feldspar employed
in industry was material occurring in pegmatite deposits as
massive crystals pure enough to require no treatment other
than hand cobbing to bring it to usable grade. More
recently, however, stimulated by the often unfavorable
location of the richer pegmatite deposits relative to
markets and by the prospect of eventual exhaustion of such
sources, technological advances have created a situation in
which more than 90 percent of the total current domestic
supply is extracted from such feldspar bearing rocks as
alaskite and from beach sands. A large part of the material
obtained from beach sands is in the form of feldspar silica
mixtures that can be used, with little or no additional
processing, as furnace feed ingredients in the manufacture
of glass. In fact, this use is so prominant that
feldspathic sands are considered in volume II of this
document under industrial sands.
Nepheline syenite is a feldspathic, igneous rock which
contains little or no free silica, but does contain
nepheline (K2O«3Na2O«lA12O3«9SiO2). The valuable properties
of nepheline are the same type as those of feldspar,
therefore, nepheline syenite, being a mixture of the two, is
a desirable ingredient of glass, whiteware and ceramic
glazes and enamels. A high quality nepheline syenite is
mined in Ontario, Canada, and is being imported into the
U.S. in ever increasing quantities for ceramics manufacture.
Deposits of the mineral exist in the U.S. in Arkansas, New
Jersey, and Montana, but mining occurs only in Arkansas,
just outside of Little Rock. There, the mineral is mined in
open pits as a secondary product to crushed rock. Since
18
-------
this is the only mining of this material in the U.S. and
posses few if any environmental problems, it will not be
considered further.
Rocks that are high in feldspar and low in iron and that
have been mined for the feldspar content have received
special names, for instance aplite (found near Piney River,
Virginia), alaskite (found near Spruce Pine, North Caroline)
and perthite. The major feldspar producing states are North
Carolina, Calfironia, the New England states, Colorado and
South Dakota.
Feldspar and feldspathic materials in general are mined by
various systems depending upon the nature of the deposits
being exploited. Because underground operations entail
higher costs, as long as overburden ratio will permit and
unless land use conflicts are a decisive factor, most
feldspathic rocks will continue to be quarried by open pit
procedures using drills and explosives. Feldspathic sand
deposits are mined by dragline excavators.
High grade, selectively mined feldspar from coarse
structured pegmatites can be crushed in jaw crushers and
rolls and then subjected to dry milling in flint lined
pebble mills.
Feldspar ores of the alaskite type are mostly beneficiated
by froth flotation processes. The customary procedure
begins with primary and secondary comminution and fine
grinding in jaw crushers, cone crushers, and rod mills,
respectively. The sequence continues with acid circuit
flotation in three stages, each stage preceded by desliming
and conditioning. The first flotation step depends on an
amine collector to float off and remove mica, and the second
uses sulfonated oils to separate iron bearing minerals. The
third step floats the iron- and mica free feldspar with
another amine collector, leaving behind a residue that
consists chiefly of quartz.
The supply demand relationships for feldspar in 1968 are
shown in Figure 2.
KYANITE (SIC 1459)
Kyanite and the related minerals andalusite,
sillimanite, dumortierite, and topaz are natural
aluminum silicates which can be converted by heating to
mullite, a stable refractory raw material with some
interstitial glass also being formed. Kyanite, and alusite
and sillinanite have the basic formula Al2O3.SiO2-
Dumortierite contains boron, and topaz contains fluorine,
19
-------
WOBLO PRODUCTION
2,128
i
I ™~~~
Conado
10
jlndyjtf j Jloetu
1 12/31/68
I/ SO
fVlo» Clnii
—rj ISICllM
1°
?.oa
Ktr
J/ Ejtimolt
UNIT! Thautand fon{ IOAI
SIC! Standard intfutlrial clooldcollos
Figure 2.
Supply-Demand Relationships for Feldspar, 1968
20
-------
both of which vaporize during the conversion to mullite
(3A12O3. 2SiO2) .
With exception of the production of a small amount of by
product kyanite sillimanite from Florida heavy mineral
operations, the bulk of domestic kyanite production is
derived from two mining operations in Virginia, operated by
the same company, and one in Georgia. The mining and
process methods used by these producers are basically the
same. Mines are open pits in which the hard rock must be
blasted loose. The ore is hauled to the nearby facilities
in trucks where the ore is crushed and then reduced in
rodmills. Three stage flotation is used to obtain a kyanite
concentrate. This product is further treated by magnetic
separation to remove most of the magnetic iron in a high
iron fraction which is wasted. Some of the concentrate is
marketed as raw kyanite, while the balance is further ground
and/or calcined to produce mullite.
Florida beach sand deposits are worked primarily for zircon
and titanium minerals, but the tailings from the zircon
recovery units contain appreciable quantities of sillimanite
and kyanite, which can be recovered by flotation and
magnetic separations. Production and marketing of Florida
sillimanite kyanite concentrates started in 1968.
The kyanite producers are located in areas of low population
density, and since the waste minerals generated by mining
and processing of kyanite ore are relatively inert, and
settle rapidly, they present no appreciable environmental
problem. The land area involved in kyanite operations is
not extensive.
The production and uses of kyanite and related minerals are
shown in Figure 3.
MAGNESITE (SIC 1459)
Magnesium is the eighth most plentiful element in the earth
and, in its many forms, makes up about 2.06 percent of the
earth's crust. Although it is found in 60 or more minerals,
only four, dolomite, magnesite, brucite, and olivine, are
used commercially to produce its compounds. Currently
dolomite is the only domestic ore used as principal raw
material for producing magnesium metal. Sea water and
brines are also principal sources of magnesium, which is the
third most abundant element dissolved in sea water,
averaging 0.13 percent magnesium by weight. Extraction of
magnesium from sea water is so closely associated with the
manufacture of refractories that it will be discussed in the
clay and gypsum products category.
21
-------
WORLD PRODUCTION
.t/ 340
I
stockpile t>aEnr>c« 5
US supply
J/ KO
5
Eio
—4 -71
KEY
KyoniJa
Jy Synthetic mulllla
SIC Stond'jrd Industrial
Unit: TSousand ificfl lent
-1'
~
-t
-t
~i
-i
iroa snj site)
fi/C )3!>l
y so
P'imory noiifsrrouS
rnilij Is
f J/c jsj/tjajfj
A/ '5
Sfcc.nJo'yrciierraui
ir.!lolj
C:X-f JJ
-------
Dolomite, the double carbonate of magnesium and calcium and
a sedimentary rock commonly interbedded with limestone,
extends over large areas of the United States. Most
dolomites are probably the result of replacement of calcium
by magnesium in preexisting limestone beds. Magnesite, the
natural form of magnesium carbonate, is found in bedded
deposits, as deposits in veins, pockets, and shear zones in
ferro-magnesium rocks, and as replacement bodies in
limestone and dolomite. Significant deposits occur in
Nevada, California, and Washington. Brucite, the natural
form of magnesium hydroxide, is found in crystalline
limestone and as a decomposition product of magnesium
silicates associated with serpentine, dolomite, magnesite,
and chromite. Olivine, or chrystolite, is a magnesium iron
silicate usually found in association with other igneous
rocks such as basalt and gabbro. It is the principal
constituent of a rock known as dunite. Commercial deposits
are in Washington, North Carolina, and Georgia.
Evaporites are deposits formed by precipitation of salts
from saline solutions. They are found both on the surface
and underground. The Carlsbad, New Mexico, and the Great
Salt Lake evaporite deposits are sources of magnesium
compounds. The only significant commercial source of
magnesium compounds from well brines is in Michigan,
although brines are known to occur in many other areas.
This form of mining is included in the clay, gypsum,
ceramics and refractory products report since it is closely
related to refractories manufacturing.
Selective open-pit mining methods are being used to mine
magnesite at Gabbs, Nevada. This facility is the only known
U.S. facility that produces magnesia from naturally
occurring magnesite ore.
Magnestie and brucite ore are delivered from the mines to
gyratory or jaw crushers where it is reduced to a minus 5
inch size. It is further crushed to minus 2.5 inches and
conveyed to storage piles. Magnesite ore is either used
directly or beneficiated by heavy media separation or froth
flotation. Refractory magnesia is produced by blending,
grinding and briquetting various grades of magnesite with
certain additives to provide the desirable refractory
product. The deadburning takes place in rotary kilns which
develop temperatures in the range of 1490-1760°C (2700 to
3200°F) .
When the source of magnesia is sea water or well brine, the
waters are treated with calcined dolomite or lime obtained
from oyster shell by calcining, to precipitate the magnesium
as magnesium hydroxide. The magnesium hydroxide slurry is
filtered to remove water, after which it is conveyed to
23
-------
rotary kilns fired to temperatures that may be as high as
1850°C (3,360°F). The calcined product contains
approximately 97 percent MgO.
The principal uses for magnesium compounds follow:
Compound and grade Use
Magnesium oxide:
Refractory grades
Caustic-calcined
U.S.P. and technical
grades
Precipitated magnesium
carbonate
Magnesium hydroxide
Magnesium chloride
Basic refractories.
Cement, rayon, fertilizer,
insulation, magnesium metal,
rubber, fluxes, refractories,
chemical processing and manu-
facturing, uranium processing,
paper processing.
Rayon, rubber (filler and
catalyst), refractories, medi-
cines, uranium processing,
fertilizer, electrical insula-
tion, neoprene compounds and
other chemicals, cement.
Insulation, rubber, pigments
and paint, glass, ink, ceramics,
chemicals, fertilizers.
Sugar refining, magnesium oxide,
Pharmaceuticals.
Magnesium metal, cement, ceramics,
textiles, paper, chemicals.
Basic refractories used in metallurgical furnaces are
produced from magnesium oxide and accounted for over 80
percent ot total domestic demand for magnesium in 1968.
Technological advances in steel production required higher
temperatures which were met by refractories manufactured
from high purity magnesia capable of withstanding
temperatures above 1930°C (3,500°F).
SHALE AND OTHER CLAY MINERALS N.E.C. ( SIC 1459)
-------
SHALES
Shale is a soft laminated sedimentary rock in which the
constituent particles are predominantly of the clay grade.
Just as clay possesses varying properties and uses, the same
can be said of shale. Thus, the word shale does not connote
a single mineral, inasmuch as the properties of a given
shale are largely dependent on the properties of the
originating clay species.
Mining of shales depends on the nature of the specific
deposit and on the amount and nature of the overburden.
Some deposits are mined underground, however, the majority
of shale deposits are worked as open quarries.
Shales and common clays are used interchangeably in the
manufacture of formed and fired ceramic products and are
frequently mixed prior to processing for optimization of
product properties. This type of product consumes about 70
percent of shale production. Certain impure shales (and
clays) have the property of expanding to a cellular mass
when rapidly heated to 1000 - 1300°C. On sudden cooling,
the melt forms a porous slag like material which is screened
to produce a lightweight concrete aggregate (60-110lb/ft.3).
Probably 20 25 percent of the total market for shale goes
into aggregate production.
APLITE
Aplite is a granitic rock of variable composition with a
high proportion of soda or lime soda feldspar. It is
therefore useful as a raw material for the manufacture of
container glass. Processing of the ore is primarily for the
purpose of obtaining sufficient particle size reduction and
for removing all but a very small fraction of iron bearing
minerals.
Aplite of sufficient quality is produced in the U.S. from
only two mines, both in Virginia (Nelson County and Hanover
County). The aplite rock in Hanover County has been
decomposed so completely that it is mined without resort to
drilling and/or blasting.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE (SIC 1496)
The mineral talc is a soft, hydrous magnesium silicate,
3MgO»USiO2»HjO. The talc of highest purity is derived from
sedimentary magnesium carbonate rocks; less pure talc from
ultra basic igneous rocks.
25
-------
Steatite has been used to designate a grade of industrial
talc that is especially pure and is suitable for making
electronic insulators. Block steatite talc is a massive
form of talc that can be readily machined, has a uniform low
shrinkage in all directions, has a low absorption when fired
at high temperature, and gives proper electrical resistance
values after firing. Phosphate bonded talc which is
approximately equivalent to natural block can be
manufactured in any desired amount. French chalk is a soft,
massive variety of talc used for marking cloth.
Soapstones refer to the sub steatite, massive varieties of
talc and mixtures of magnesium silicates which with few
exceptions have a slippery feeling and can be carved by
hand.
Pyrophyllite is a hydrous aluminum silicate similar to talc
in properties and in most applications, and its formula is
A12.Oj«4SiO2»HjO. It is principally found in North Carlina.
Wonderstone is a term applied to a massive block pyro-
phyllite from the Republic of South Africa. The uses of
pyrophyllite include wall tile, refractories, paints,
wallboard, insecticides, soap, textiles, cosmetics, rubber,
composition battery boxes and welding rod coatings.
During 1968 talc was produced from 52 mines in Alabama,
California, Georgia, Maryland, Montana, Nevada, New York,
North Carolina, Texas, and Vermont. Soapstone was produced
from 13 mines in Arkansas, California, Maryland, Nevada,
Oregon, Virginia, and Washington. Pyrophyllite was produced
from 10 mines in California and North Carolina. Sericite
schist, closely resembling pyrophyllite in physical and
chemical properties, was produced in Pennsylvania and
included with pyrophyllite statistics.
The facility size breakdown is as follows:
Numbers of Production
Facilitigs tons/Y£
6 < 1,000
22 1,000 - 10,000
20 10,000 - 100,000
3 100,000 - 1,000,000
Slightly more than half of the industrial talc is mined
underground and the rest is quarried as is soapstone and
pyrophyllite. Small quantities of block talc also are
removed by surface method. Underground operations are
usually entirely within the ore body and thus require timber
supports that must be carefully placed in talc operations
because of the slippery nature of the ore.
26
-------
Mechanization of underground mines has become common in
recent years, especially in North Carolina and California
where the ore body ranges in thickness from 10 to 15 feet
and dips 12 to 19 degrees from horizontal. In those mines
where the ore body suffers vein dips of greater than 20
degrees, complex switch backs are introduced to provide the
gentle slopes needed for easier truck haulage of the ore.
At one quarry in Virginia, soapstone for decorative facing
is mined in large blocks approximately 1.2 by 2.U by 3.0 m
(4 by 8 by 10 ft) which are cut into slices by gang saws
with blades spaced about 7.6 cm (3 in) apart. In the mining
of block talc of crayon grade, a minimum of explosive is
used to avoid shattering the ore; extraction of the blocks
being accomplished with hand equipment to obtain sizes as
large as possible.
When mining ore of different grades within the same deposit,
selective mining and hand sorting must be used. Operations
of the mill and mine are coordinated, and when a certain
specification is to be produced at the mill, the desired
grade of ore is obtained at the mine. This type of mining
and/or hand sorting is commonly used for assuring the proper
quality of the output of crude talc group minerals.
Roller mills, in closed circuit with air separators, are the
most satisfactory for fine grinding (100 to 325 mesh) of
soft talcs or pyrophyllites. For more abrasive varieties,
such as New York talc and North Carolina ceramic grade
pyrophyllite, grinding to 100 to 325 mesh is effected in
quartzite or silex lined pebble mills, with quartzite
pebbles as a grinding medium. These mills are ordinarily in
closed circuit with air separators but some times are used
as batch grinders, especially if reduction to finer particle
sizes is required.
Talc and pyrophyllite are amenable to processing in an addi-
tional microgrinding apparatus. Microgrinding or
micronizing is also done in fluid system with subsequent air
drying of the product.
The production and uses of talc, soapstone and pyrophyllite
are shown in Figure U.
NATURAL ABRASIVES (SIC 1499)
Abrasives consist of materials of extreme hardness that are
used to shape other materials by grinding or abrading
action. Such materials may be classified as either natural
or synthetic (manufactured). Of interest here are the
natural abrasive minerals which include cleamorid, corundum,
emery, pumice, tripoli and garnet. Of lesser importance,
other natural abrasives include feldspar, calcined clays.
27
-------
CC
WORLD PRODUCTION
4,738
1
I
Jcpcn
1,833
U.S.S.R.
£/ 408
IS4
i
United States
958
F^c ncs
.2/232
*/\zl
Cur.cda
78
0 , •, _ _
5 Imports 1
_ji-'«j- K i U^m<.
24 r i
i
jj
I
JL|
i
~ I industrv n?osks 1
iGS
Ceromic*
21
3Z69)
248
Industry stocks
12/31/68
161
! /1 / S 3 f
V 13!
U.S.demand
886
KEY
*Lt Estlmote
SIC Slandcrd IndastricJ Classification
Units: Thousand short tons
Paint
IS 1C 285II
I 70
Roofing
(SIC295Z)
65
Insecticides
(SIC 2879)
69
Paper
(SIC 26£U
39
Refractories
ISIC 3Z35)
34
RuOber
(SIC306SJ
Toilef preparations
(SIC2844}
35
Other
182
Figure 4.
Supply-Demand Relationships for Talc, Soapstone, and Pyrophyllite, 1968
-------
chalk and silica in its many forms such as sandstones, sand,
flint and diatomite.
CORUNDUM
Corundum is a mineral with the composition A1203
crystallized in the hexagonal system which was formed by
igneous and metamorphic processes.
Abrasive grade corundum has not been mined in the United
States for more than 60 years. There is no significant
environmental problem posed by the processing of some 2,360
kkg of corundum per year (1968 data); and further
consideration will be dropped.
EMERY
Emery consists of an intimate admixture of corundum with
magnetite or hematite, and spinel.
The major domestic use of emery involves its incorporation
into aggregates as a rough ground product for use as heavy
duty non skid flooring and for skid resistant highways.
Additional quantities (25 percent of total consumption) are
used in general abrasive applications.
Recent statistics show the continuing down turn in demand
for emery resulting from the increasing competition with
such artificial abrasives as A12OJ and SIC. Production is
estimated to be 11,000 kkg/yr (10,000 tons/yr). Emery was
not considered further in this report because it was not
deemed economically significant and no environmental
problems were noted.
TRIPOLI
Tripoli is the generic name applied to a number of fine
grained, lightweight, friable, minutely porous, forms of
decomposed siliceous rock, presumably derived from siliceous
limestones or calcareous cherts. Tripoli is often confused,
in both the trade and technical literature, with tripolite,
a diatomaceous earth (diatomite), found in Tripoli, North
Africa.
The two major working deposits of tripoli are those in the
Seneca, Missouri area and in southern Illinois. The
Missouri ore resembles tripolite and was incorrectly named
tripoli. The name has persisted and now has definite
physical and trade association with the ore from the
Missouri Oklahoma field. The material from the southern
Illinois area is often refered to as "amorphous11 or "soft"
silica. In both cases the ore contains 97 to 99 percent
29
-------
S1OI2 with minor additions of alumina, iron, lime, soda and
potash. The rottenstone obtained from Pennsylvania is of
higher density and has a composition approximately 60
percent silica, 18 percent alumina, 9 percent iron oxides, 8
percent alkalies and the remainder lime and magnesia.
Tripoli mining involves two different processes depending on
the nature of the ore and of the overburden. In the
Missouri Oklahoma area, the small overburden of
approximately six feet in thickness coupled with tripoli
beds ranging from 0.6 to 1.3m (2 to 14 ft) in thickness,
lends itself to open pit mining. The tripoli is first hand
sorted for texture and color, then piled in open sheds to
air dry (the native ore is saturated with water) for three
to six months. The dried material is subsequenly crushed
with hammer mills and rolls.
In the southern Illinois field, due to the terrain and the
heavy overburden, underground mining using a modified room-
and-pillar method is practiced. The resulting ore is
commonly wet milled after crushing to 0.63 to 1.27 cm (0.25
to 0.50 in) sizing, the silica is fine ground in tube mills
using flint linings and flint pebbles in a closed circuit
system with bowl classifiers. The resulting accurately
si2ed product is thickened, dried and packed for shipment.
Tripoli is primarily used as an abrasive or as a constituent
of abrasive materials for such uses as polishing and buffing
of such materials as copper, aluminum, brass and zinc. In
addition, the pulverized product is widely used as the
abrasive element in scouring soaps and powders, in polishes
for the metal working trades and as a mild mechanical
cleaner in washing powders for fabrics. The pure white
product from southern Illinois, when finely ground, is
widely used as a filler in paint. The other colors of
tripoli are often used as fillers in the manufacture of
linoleum, phonograph records, pipe coatings and so forth.
Total U. S. production of tripoli in 1971 was of the order
of 68,000 kkg, some 70 percent of which was used as
abrasive, the remainder as filler.
GARNET
Garnet is an orthosilicate having the general formula
3BO«X2O3»3SiO2 where the bivalent element R may be calcium,
magnesium, ferrous iron or manganese; the trivalent element
x, aluminum, ferric iron or chromium, rarely titanium;
further, the silicon is occasionally replaced by titanium.
30
-------
The members of the garnet group of minerals are common
accessory minerals in a large variety of rocks, particularly
in gneisses and schists. They are also found in contact
metamorpnic deposits, in crystalline limestones; pegmatites;
and in serpentines. Although garnet deposits are located in
almost every state of the United states and in many foreign
countries, practically the entire world production comes
from New York and Idaho. The Adirondack deposit consists of
an alamandite garnet having incipient lamellar parting
planes which cause it to break under pressure into thin
chisel edge plates. Even when crushed to very fine size
this material still retains this sharp silvery grain shape—
—a feature of particular importance in the coated abrasive
field.
The New York mine is a surface site worked by open quarry
methods. The ore is quarried in benches about 10.7 m (35
ft) in height, trucked to the mill and dumped on a pan
conveyor feeding a 61 - 91 cm (2U x 36 in) jaw crusher. The
secondary crusher which is a standard 4 feet Symonds cone is
in closed circuit with a 1-1/2 inch screen. The minus 3.8
cm (1 1/2 in) material is screened on a 10 mesh screen. The
oversize from the screen goes to a heavy media separation
facility while the undersize is classified and concentrated
on jigs. The very fine material is treated by flotation.
The combined concentrates, which have a garnet content of
about 98 percent, are then crushed, sized and heat treated.
It has been found that heat treatment, to about 700 to 800°
C will improve the hardness, toughness, fracture properties
and color of the treated garnets.
The only other significant production of garnets in the
United States is situated on Emerald Creek in Benewah
County, Idaho. This deposit is an alluvial deposit of
alamandite garnets caused by the erosion of soft mica
schists in which the garnets have a maximum grain size of
about 4.8 mm (3/16 in). The garnet bearing gravel is mined
by drag line, concentrated on trommels and jigs then crushed
and screened into various sizes. This garnet is used mainly
for sandblasting and as filtration media.
Approximately 45 percent of the garnet marketed is used in
the manufacture of abrasive coated papers, about 35 percent
in the glass and optical industries with the remainder for
sand blasting and miscellaneous uses.
DIATOMITE (SIC 1499)
Diatomite is siliceous rock of sedimentary origin which may
vary in the degree of consolidation but which consists
mainly of the fossilized remains of the protective silica
shells formed by diatoms, single celled non flowering
31
-------
microscopic facilities. The size, shape and structure of
the individual fossils and their mass packing
characteristics result in microscopic porous material of low
specific gravity.
There are numerous sediments which contain diatom residues,
admixed with substantial amounts of other materials
including clays, carbonates or silica; these materials are
classified as diatomaceous silts, shales or mudstones; they
are not properly diatomite, a designation restricted to
material of such quality that it is suitable for commercial
uses. The terms diatomaceous earth and kieselgur are
synonymous with diatomite; the terms infusorial earth and
tripolite are considered obsolete.
Diatomaceous silica is the most appropriate designation of
the principal component of diatomite; that is, the substance
of the fossil silica shell is the major constituent of
beneficiated diatomite of processed diatomaceous products.
Commercially useful deposits of diatomite show Si02 concen-
tration ranging from a low of 86percent (Nevada) to a high
of 90.75 percent (Lompoc, California) for the United States
producers; the SiO£ content of foreign sources is somewhat
lower. The remainder consists of alumina, iron oxide,
titanium oxide, and lesser quantities of phosphate,
magnesia, and the alkali metal oxides. In addition, there
is usually some residual organic matter as indicated by
ignition losses which are typically of the order of 4 to 5
percent.
The formation of diatomite sediments was dependent upon the
existence of the proper environmental conditions over an
adequate period of time to permit a significant accumulation
of the skeletal remains. These conditions include a
plentiful supply of nutrients and dissolved silica for
colony growth and the existence of relatively quiescent
physical conditions such as exist in protected marine
estuaries or in large inland lakes. In addition, it is
necessary that these conditions existed in relatively recent
times in order that subsequent metamorphic processes would
not have altered the diatomite to the rather more indurated
materials such as porcelanite and the opaline cherts.
The upper tertiary period was the period of maximum diatom
growth and subsequent deposit formation. The great beds
near Lompoc, California are upper Miocene and lower Pliocene
(about 20 x 10* years old); formations of similar origin and
age occur along the California coast line from north of San
Francisco to south of San Diego. Most of the dry lake
deposits of California, Nevada, Oregon and Washington are of
freshwater origin formed in later tertiary of Pleistocene
(less than 12 x 10* years old.)
32
-------
Currently, the only significant production of diatomite
within the U.S. is in the western states, with California
the leading producer, followed by Nevada, Oregon and
Washington. Commonly, beds of ordinary sedimentary rocks
such as shales, sandstones, or limestone overlie and
underlie the diatomite beds, thus the first step in mining
requires the removal of the overburden (which ranges from
zero to about 15 times the thickness of the diatomite bed)
by ordinary earth moving machinery. The ore is ordinarily
dug by power shovels without the necessity of previous
fragmentation by drilling or blasting although such
operations may be carried out.
Initial processing of the ore involves size reduction by a
primary crusher followed by further size reduction and
drying (some diatomite ores contain up to 60 percent water)
in a blower hammer mill combination with a pneumatic feed
and discharge system. The suspended particles in the hot
gases pass through a series of cyclones and a baghouse where
they are separated into appropriate particle size groups.
The uses of diatomite result from the size (from 10 to
greater than 500 microns in diameter), shape (generally
spiny structure of intricate geometry) and the packing
characteristics of the diatom shells. Since physical
contact between the individual fossil shells is chiefly at
the outer points of the irregular surfaces, the resulting
compact material is microscopically porous with an apparent
density of only 5 to 16 pounds per cubic foot for ground
diatomite. The processed material has dimensional stability
to temperatures of the order of 400° C. The domestic
consumption of diatomite is shown in Figure 5.
GRAPHITE (SIC 1499)
Natural graphite is the mineral form of elemental carbon,
crystallized predominately in the hexagonal system, found in
silicate minerals of varying kind and percentage. The three
principal types of natural occurrence of graphite are
classified as lump, amorphous and crystalline flake; a
classification based on major differences in geologic origin
and occurrence.
Lump graphite occurs as fissure filled veins wherein the
graphite is typically massive with particle size ranging
from extremely fine grains to coarse, platy intergrowths or
fibrous to acicular aggregates. The origin of vein type
deposits is believed to be either hydrothermal or
pneumatolytic since there is no apparent relationship
between the veins and the host rock. A variety of minerals
generally in the form of isolated pockets or grains, occur
33
-------
J/ /, 7* 30
; (j. s. s./e.
ITALY
& 3-52
-70
(J.S.
Mey:
SJ
r~
237
/-.' A !
I
SZ.3
Figure 5. Supply-Demand Relationships for Dictcrrme, 1968
-------
with graphite, including feldspar, quartz, mica, pyroxene,
zircon, rutile, apatite and iron sulfides.
Amorphous graphite, which is fine grained, soft, dull black,
earthy looking and ususally somewhat porous, is formed by
metamorphism of coalbeds by nearby intrusions. Although the
purity of amorphous graphite depends on the purity of
coalbeds from which it was derived, it is usually associated
with sandstones, shales, slates and limestones and contains
accessory minerals such as quartz, clays and iron sulfides.
Flake graphite, which is believed to have been formed by
metamorphism from sedimentary carbon inclusions within the
host rocks, commonly occurs disseminated in regionally
metamorphosed sedimentary rocks such as gneisses, schists
and marbles.
The only domestic producer is located near Burnet, Texas
and, mines the flake graphite by open pit methods utilizing
an 5.5 m (18 ft) bench pan. The ore is hard and tough and
thus requires much secondary blasting. The broken ore is
hauled by motor trucks to the mill.
Because of the premium placed upon the mesh size of flake
graphite, the problem in milling is one of grinding to free
the graphite without reducing the flake size excessively;
this is difficult because during grinding, the graphite
flakes are cut by quartz and other sharp gangue materials,
thus rapidly reducing the flake size. However, if the flake
can be removed from most of the quartz and other sharp
minerals soon enough, subsequent grinding will usually
reduce the size of the remaining gangue, with little further
reduction in the size of the flake. Impact grinding or
essentially pure flake in a ball mill reduces flake size
rather slowly, the grinding characteristics of flake
graphite under these conditions being similar to those of
mica.
Graphite floats readily and does not require a collector;
hence, flotation has become the accepted method for
beneficiating disseminated ores. Although high recoveries
are common, concentrates with acceptable graphitic carbon
content are difficult to attain and indeed with some ores
impossible. The chief problem lies with the depression of
the gangue minerals since relatively pure grains of quartz,
mica, and other gangue minerals inadvertently become smeared
with fine graphite, making them floatable resulting in the
necessity for repeated cleaning of the concentrates to
attain high grade products. Regrinding a rougher
concentrate reduces the number of cleanings needed. Much of
the natural flake either has a siliceous skeleton (which can
be observed when the carbon is burned) or is composed of a
35
-------
layer of mica between outer layers of graphite making it
next to impossible to obtain a high grade product by
flotation. The supply demand relationships for 1968 are
shown at Figure 6,
MISCELLANEOUS NON-METALLIC MINERALS, N.E.C.
(SIC 1499)
JADE
The term jade is applied primarily to the two minerals
jadeite and nephrite, both minerals being exceedingly tough
with color varying from white to green. Jadeite, which is a
sodium aluminum silicate (NaAlSi2O6) contains varying
amounts of iron, calcium and magnesium is found only in
Asia. Nephrite is a tough compact variety of the mineral
tremolite (Ca2Mg5Si8O.2_2 (OH) 2) which is an end member of an
isomorphous series where in iron may replace the magnesium.
In the U.S. production of jade minerals is centered in
Wyoming, California and Alaska.
NOVACULITE
Novaculite is a generic name for massive and extensive
geologic formations of hard, compact, homogenous,
microcrystalline silica located in the vicinity of Hot
Springs, Arkansas. There are three strata of novaculite
lower, middle, and upper. The upper strata is not compacted
and is a highly friable ore which is quarried, crushed,
dried and air classified prior to packaging. Chief uses are
as filler in plastics, pigment in paints, and as a micron
sized metal polishing agent.
WHETSTONE
Whetstones, and other sharpening stones, are probably
produced in small volume across the U.S. wherever deposits
of very hard silaceous rock occur. However, the largest
center of sharpening stone manufacture is in the Hot
Springs, Arkansas, area. This area has extensive out-
cropping deposits of very hard and quite pure silica, called
"Novaculite", which are mined and processed into whetstones.
Most of the mining and processing is done on a very small
scale by individuals or very small companies.
The total production in 1972 of all special silica stone
products (grinding pebbles, grindstones, oilstones, tube-
mill liners, and whetstones) was only 2,910 kkg (3,240
tons), with a value of $670,000. This production and value
is neither economically nor environmentally significant and
will not be treated further in this report.
36
-------
V.'CS-D
UJ
W"X;CO L—55.'SO-.J :^50'1i j fTnc^Xy ~n- !
71.7JO I
S'.C S-lanscfi btfutlrial
yniJ: 3ho-r tans
Gcv: Stocv.piic aaiar.ee. ,43,653
(A) Mcfejasy crySicJIiic flake...... 25,829
iilifie fit.£:.„.„ 7, 206
EC! Ceylo-i Q.TSf&hous Ji.mp "5,
CO) Ct
Figure 6. Supply-Demand Relationships for Nahira! Graphife, 1968
-------
-------
SECTION IV
INDUSTRY CATEGORIZATION
INTRODUCTION
In the development of effluent limitations guidelines and
recommended standards of performance for new sources in a
particular industry, consideration should be given to
whether the industry can be treated as a whole in the
establishment of uniform and equitable guidelines for the
entire industry or whether there are sufficient differences
within the industry to justify its division into categories.
For this segment of the mineral mining and processing
industry, which includes 21 mineral types, the following
factors were considered as possible justifications for
industry categorization and subcategorization:
1) manufacturing processes;
2) raw materials
3) pollutants in effluent waste waters;
H) product purity;
5) water use volume;
6) facility size;
7) facility age; and
8) facility location.
INDUSTRY CATEGORIZATION
The first categorization step was to segment the mineral
mining and processing industry according to product use.
Thus, Volume I is "Mining of Minerals for the Construction
Industry," Volume II is "Mining of Minerals for the Chemical
and Fertilizer Industries," and this volume. Volume III, is
"Mining of Clay, Ceramic, Refractory and Miscellaneous
Minerals."
The reason for this division is twofold. First, the
industries in each volume generally have the same waste
water treatment problems. Secondly, this division results
in development documents that are not so big that the reader
39
-------
may really forget earlier points as he reads from section to
section,
The first cut in subcategorization was made on a commodity
basis. This was necessary because of the large number of
commodities and in order to avoid insufficient study of any
one area. Furthermore, the economics of each commodity
differs and an individual assessment is necessary to insure
that the economic impact is not a limiting factor in
establishing effluent treatment technologies. Table 4 lists
the 17 subcategories in this report.
FACTORS CONSIDERED
Manufacturing Processes
Each commodity can be further subcategori2ed into three very
general classes - dry crushing and grinding, wet crushing
and grinding (shaping), and crushing and beneficiation
(including flotation, heavy media, et cetera, where such
differences exist. Each of these processes is described in
detail in Section V of this report, including process flow
diagrams pertinent to the specific facilities using the
process.
Raw Materials
The raw materials used are principally ores, which vary
across this segment of the industry and also vary within a
given deposit,. Despite these variations, differences in ore
grades do not generally affect the ability to achieve the
effluent limitations. In cases where it does, different
processes are used, as is the case for feldspar and
subcategorization is better applied by process type as
described in the preceeding paragraph.
Product Purity
The mineral extraction processes covered in this report
yield products which vary in purity from what would be
considered a chemical technical grade to an essentially
analytical reagent quality. Product purity was not
considered to be a viable criterion for categorization of
the industry. Pure product manufacture usually generates
more waste than the production of lower grades of material,
and thus could be a basis for subcategorization. As is the
case for variation of ore grade discussed under raw
materials above, pure products usually result from different
beneficiation processes, and subcategorization is applied
more advantageously there.
40
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TABLE 4
Commodity
Bentonite
Fire clay
Fuller's earth
Kaolin and ball
clay
Industry
SIC Code SubcategoicY
Feldspar
Kyanite
Magnesite
Shale 6 Common
Clay, NEC
Talc Minerals
Group
1452
1453
1454
1455
1459
1459
1459
1459
1496
Natural Abrasives
Diatomite
Graphite
Misc. Minerals,
Not elsewhere
classified
1499
1499
1499
1499
No further subeategorization
No further subeategorization
Attapulgite
MontmorilIonite
Dry Kaolin Mining
and Processing
Kaolin Mining and
Wet Processing for
High-Grade Product
Ball Clay - Dry
Processing
Ball Clay - Wet
Processing
Feldspar Wet
Processing
Feldspar Dry
Processing
No further subeategorization
No further subeategorization
Shale
Aplite
Talc Minerals Group,
Dry Process
Talc Minerals Group,
Ore Mining & Washing
Talc Minerals Group,
Ore Mining, Heavy Media
and Flotation
Garnet
Tripoli
No further subeategorization
No further subeategorization
Jade
Novaculite
41
-------
Facility Size
For this segment of the industry, information was obtained
from more than 90 different mineral mining sites. Capacity
varied from as little as 2 to 6,800 kkg/day. The variance
of this factor was so great that facility size was not felt
to be useful in categorizing this segment of the industry.
Furthermore setting standards based on pounds pollutant per
ton production minimizes the differences in facility sizes.
The economic impact on plant size will be addressed in
another study.
Facility Age
The newest facility studied was less than a year old and the
oldest was 90 years old. There is no correlation between
facility age and the ability to treat process waste water to
acceptable levels of pollutants. Also the equipment in the
oldest facilities either operates on the same principle or
is identical to equipment used in modern facilities.
Therefore, facility age was not an acceptable criterion for
categorization.
Facility Location
The locations of the more than 90 mineral mining and
processing sites studied are in twenty states spread from
coast to coast and north to south. Some facilities are
located in arid regions of the country, allowing the use of
evaporation ponds and surface disposal on the facility site.
Other facilities are located near raw material mineral
deposits which are highly localized in certain areas of the
country. In general the principal factor within facility
location affecting effluent quantity or quality is the
amount of precipitation and evaporation. Appropriate
consideration of these factors was taken where applicable,
most notably mine pumpout and storm runoff.
42
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SECTION V
WATER USE AND WASTE CHARACTERIZATION
INTRODUCTION
This section discusses the specific water uses in the clay,
ceramic, refractory, and miscellaneous minerals segment of
the mineral mining and processing industry, and the amounts
of process waste materials contained in these waters. The
process water raw waste loads are given in terms of
kilograms per metric ton of either product produced or ore
processed. The specific water uses and amounts are given in
terms of liters per metric ton of product produced or ore
mined. For each of the facilities contacted in this study.
The treatments used by the mining and processing facilities
studied are specifically described and the amount and type
of water borne waste effluent after treatment is
characterized.
The verification sampling data measured at specific
facilities for each subcategory is included in this report
where industry data and data from other sources is lacking.
SPECIFIC WATER USES
Waste water originates in the mineral mining and processing
industry from the following sources.
(1) Non-contact cooling water
(2) Process generated waste water
wash water
transport water
scrubber water
process and product consumed water
miscellaneous water
(3) Auxiliary processes water
(U) Storm and ground water - mine water
storm runoff
Non-contact cooling water is that cooling water which does
not come into direct contact with any raw material, inter-
mediate product, by-product or product used in or resulting
from the process or any process water. Such water will be
regulated by general limitations applicable to all
industries.
43
-------
Process generated waste water is that water which, in the
mineral processing operations such as crushing, washing
beneficiation, comes into direct contact with any raw
material, intermediate product, by-product or product used
in or resulting from the process.
Auxiliary process water is that used for processes necessary
for the manufacture of a product but not contacting the
process materials. For example, water treatment
regeneration is an auxiliary process. Such water will be
regulated by general limitations applicable to all
industries.
The quantity of water usage for facilities in the clayf
ceramic, refractory and miscellaneous minerals segment of
the mineral mining and processing industry generally ranges
from zero to 2,200,000 I/day (0 to 580,000 gal/day). In
general, the facilities using very large quantities of water
use it for heavy media separation and flotation processes
and, in some cases, wet scrubbing and non-contact cooling.
Non-Contact cooling Water
The largest use of non-contact cooling water in this segment
of the mineral mining industry is for the cooling of
equipment, such as kilns, pumps and air compressors.
Contact cooling Water
Insignificant quantities of contact cooling water is used in
this segment of the mineral mining industry. When used, it
usually either evaporates immediately or remains with the
product.
Wash water
This water is process water because it comes into direct
contact with either the raw material, reactants or products.
Examples are ore washing to remove fines and filter cake
washing. Waste effluents can arise from these washing
sources, due to the fact that the resultant solution or
suspension may contain impurities or may be too dilute a
solution to reuse or recover.
Transport Water
Water is widely used in the mineral mining industry to
transport ore to and between various process steps. water
is used to move crude ore from mine to facility, from
crushers to grinding mills and to transport tailings to
final retention ponds. Transport water is process water.
44
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Scrubber Water
Particularly in the dry processing of many of the minerals
in this industry, wet scrubbers are used for air pollution
control. These scrubbers are primarily used on dryers,
grinding mills, screens, conveyors and packaging equipment.
Scrubber water is process water.
Process and Product Consumed Water
Process water is primarily used in this industry during
blunging, pug milling, wet screening, log washing, heavy
media separation and flotation unit processes. The largest
volume of water is used in the latter two processes.
Product consumed water is often evaporated or shipped with
the product as a slurry or wet filter cake.
Miscellaneous Water
These water uses vary widely among the facilities with
general usage for floor washing and cleanup, safety showers
and eye wash stations and sanitary uses. The resultant
streams are either not contaminated or only slightly
contaminated with wastes. The general practice is to
discharge such streams without treatment or combine with
process water prior to treatment.
Another miscellaneous water use in this industry involves
the use of sprays to control dust at crushers, conveyor
transfer points, discharge chutes and stockpiles. This
water is usually low volume and is either evaporated or
absorbed in the ore. The water uses so described are
process waters.
Auxiliary Processes Water
Auxiliary process water include blowdowns from cooling
towers, boilers and water treatment. The volume of water
used for these purposes in this industry is minimal.
However, when they are present, they usually are highly
concentrated in waste materials.
Storm and Ground Water
Water will enter the mine area from three natural sources
direct precipitation, storm runoff and ground water
intrusion. Water contacting the exposed ore or disturbed
overburden will become contaminated.
Storm water and runoff can also become contaminated at the
processing site from storage piles, process equipment and
dusts that are emitted during processing.
45
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— a
PROCESS WASTE CHARACTERIZATION
The mineral products are discussed in the Standard
Industrial Classification Code numerical sequence in this
section. For each mineral product the following information
is given:
a short description of the processes at the
facilities studied and pertinent flow diagrams;
— raw waste load data per unit weight of product
or raw material processed;
— water consumption data per unit weight of product
or raw material processed;
— specific facility waste effluents found and the
post-process treatments used to produce them.
BENTONITE (SIC 1452)
Process Description
Bentonite is mined in dry, open pit quarries. After the
overburden is stripped off, the bentonite ore is removed
from the pit using bulldozers, front end loaders, and/or pan
scrapers. The ore is hauled by truck to the processing
facility. There, the bentonite is crushed, if necessary,
dried, sent to a roll mill, stored, and shipped, either
packaged or in bulk.
Dust generated in drying, crushing, and other facility
operations is collected using cyclones and bags. In
facility 3030 this dust is returned to storage bins for
shipping. A general process flowsheet is given in Figure 7.
Raw Waste Load
Waste is generated in the mining of bentonite in the form of
overburden, which must be removed to reach the bentonite
deposit. Waste is also generated in the processing of
bentonite as dust from drying, crushing, and other facility
operations.
Water Use
There is no water used in the mining or processing of
bentonite.
46
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OPEN PiT
QUARRY
CRUSHER
VENT
DRYER
ROLL MILL
STORAGE
BINS
SCREENS
I
_J
PRODUCT
FIGURE 7.
BENTONITE MINING AND PROCESSING
-------
Waste Water Treatment,
Since there is no water used in bentonite mining or
processing, no waste water is generated.
Effluent and Disposal
There is no discharge of any waste water from bentonite
operations. The solid overburden removed to uncover the
bentonite deposit is returned to mined-out pits for land
disposal and eventual land reclamation. Dust collected from
processing operations is either returned to storage bins as
product or it is land-dumped.
48
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FIRE CLAY (SIC 1H53)
Fire clay is principally kaolinite but usually contains
other minerals such as diaspore, boehmite, gibbsite and
illite. It can also be a ball clay, a bauxitic clay, or a
shale. Its main use is in refractory production and only
the mining is covered here. Due to the similarity in all
types of clay mining, this section will also serve for
common clay mining and processing
Process Description
Fire clay is obtained from open pits using bulldozers and
front-end loaders for removal of the clay. Blasting is
occasionally necessary for removal of the hard flint clay.
The clay is then transported by truck to the facility for
processing. This processing includes crushing, screening,
and other specialized steps, for example, calcination.
There is at least one case (facility 30U7) where the clay is
shipped without processing. However, most of the fire clay
mined is used near the mine site for producing refractories.
A general process diagram is given in Figure 8.
Raw Waste Load
The solid waste generated in fire clay mining is overburden
which is used as fill to eventually reclaim mined-out areas.
Mine pumpout is the only other waste in this subcategory.
water Use
There is no water used in fire clay mining. However, due to
rainfall and ground water seepage, there can be water which
accumulates in the pits and must be removed. Mine pumpout
is intermittent depending on frequency of rainfall and
geographic location. Flow rates are not generally
available. In many cases the facilities provide protective
earthen dams and ditches to prevent intrusion of external
storm runoff in the clay pits. No process water is used in
the mine.
Waste Water Treatment
There is no process waste water. In some cases, settling
ponds are employed to reduce the amount of suspended solids
in the mine pumpout before discharge. Usually, mine pumpout
is discharged to a nearby body of water, to a watershed, or
is evaporated on-land.
49
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1
OPEN
PIT
CRUSH
SPRFFM
REFRACTORY
OPERATIONS
•PRODUCT
Cn
O
CALCINE
PRODUCT
PRODUCT
FIGURE 8.
FIRE CLAY MINING AND PROCESSING
-------
Effluent and Disposal
There is no discharge of process waste waters. Mine pumpout
is discharged either after settling or with no treatment.
The effluent quality of mine pumpout at a few mines are as
follows:
Mine
3083
3084
Treatment
Pond
Lime 6 Pond
pH
7.25
6.5
TSS
mg/1
3
26.4
Total
Fe
mg/1
3087
3300
lime, combined
with other
waste streams
None
6.0-6.9
3301
3302
None
None
6.9
8.3
2
30
3303
3307
None
None
7.0
9.2
1
5
3308
3309
Pond
Pond
5.0
4.2
16
20
80
3310
None
3.0
16
51
-------
FULLER'S EARTH (SIC 1454)
Fuller's Earth is a clay, usually high in magnesia, which
has decolorizing and absorptive properties. Production from
the region that includes Decatur County, Georgia, and
Gadsden County, Florida, is composed predominantly of the
distinct clay mineral attapulgite. Most of the Fuller's
Earth occurring in the other areas of the U.S. contains
primarily montmorillonite. Six facilities, representing
83 percent of the total U.S. production of Fuller's Earth,
provided the data for this section.
ATTAPULGITE
Process Description
Attapulgite is mined from open pits, with removal of
overburden using scrapers and draglines. The clay is also
removed using scrapers and draglines and is trucked to the
facility for processing. Processing consists of crushing
and grinding, screening and air classification, pug milling
(optional), and a heat treatment that may vary from simple
evaporation of excess water to thermal alteration of crystal
structure. A general process diagram is given in Figure 9.
Raw Waste Load
Dusts and fines are generated from drying and screening
operations at facility 3060. This slurried waste is sent to
worked-out pits which serve as settling ponds, in the last
year the ponds have been enlarged and modified to allow for
complete recycle of this waste water. The ponds have not
yet totally filled,however the company anticipates no
problems. There is no discharge at this time of process
water. At facility 3058 waste is generated from screening
operations as fines which until presently were slurried and
pumped to a settling pond. With the installation of new
reconstituting equipment these fines are recycled and there
is no discharge of process water. The settling pond however
is maintained in event of breakdown or the excessive
generation of fines. Facility 3088 also has installed
recycle ponds recently and anticipates no trouble. Facility
3089 uses a dry inicro-pulsair system for air pollution
control, therefore there is no discharge of process water.
According to the company they are within state air pollution
requirements.
52
-------
Ul
u>
WftTER & SCRUBBERS KiLN
OPEN t
PITS
WATER—
VENT T
! 1
CRUSHING ROTAW
9 AND W riOYPR<;
SCREENING DRYtHb
f ,*
1 «
1 I
1
PUG _j
MSLL — — —
f
I 1
_____ g
1
1 H
— ©^ MILLS *«— >lM SCREENS
n
1
WCTER BS|
?
? POND
POND " I
&
LEGEND:
--}.
1 EFFLUENT
1
EFFLUENT
.TEftNATE RJCX^SS ROUTES
FIGURE 9.
FULLER'S EARTH AND
(ATTAPULGITE)
-------
Water Use
No water is used in the mining , but rain and ground water do
collect in the pits, particularly during the rainy season.
This type of clay settles rapidly and mine pumpout is
generally clear except when overburden gets into the water.
Only one company, 3089, uses settling ponds for treatment of
dry weather mine pump-out. No company attempts to treat wet
weather mine pump-out or surface runoff. Untreated creek
water serves as source and make-up for facilities 3058 and
3060. Water is used by facility 3058 for cooling, pug
milling, and during periodic overload for waste fines
s lurrying. This slurrying has not occurred since
installation of a fines reconstitution system. However it
is maintained as a back-up system. Facility 3060 also uses
water for cooling and pug milling, and, in addition, uses
water in dust scrubbers for air pollution control. There is
no recycle of process water at either facility, all being
evaporated, sent to ponds, and/or eventually discharged.
Typical flows are:
1/kkg of_produgt
3058 3060
Intake:
Make-up 460 (110) total unknown
includes average
intermittent needs
Use:
cooling 184 (44) unknown amount
waste disposal 230 (55) 345-515
and dust collection intermittent (82-122)
pug mill 46 (11) 42 (10)
Consumption:
cooling water
discharge none unknown
process discharge none none
evaporation 230 (55) 42 (10)
Total 460 (110) unknown
Waste water Treatment
Mine pumpout at facilities 3060 and 3058 is discharged
without treatment. Facility 3089 uses two settling ponds in
series to treat mine pumpout, however they do not attempt to
treat wet weather mine pumpout. Bearing cooling water at
facility 3060 is pumped directly back to the creek, with no
-------
treatment, while water used in pugging and kiln cooling is
evaporated in the process. Scrubber waters are directed to
settling ponds before recycle to the scrubber. At facility
3058 cooling and pug mill water is evaporated in the
process.
Effluent and Disposal
Facilities 3060 and 3088 at the present time have recycle
ponds. However, due to evaporation and possibly seepage
little or no actual recycling is occurring at this time.
Facilities 3058 and 3087 use dry air pollution equipment and
fines reconstituters; therefore they have no discharge.
MONTMORILLONITE
Montmorillonite wastes present more of a settling problem in
water than attapulgite wastes. The information presented
below is based on 3 of 4 facilities in this subcategory.
This represents over 80 percent of the U.S. montmorillonite
production.
Process Description
Montmorillonite is mined from open pits. Overburden is
removed by scrapers and/or draglines, and the clay is
draglined and loaded onto trucks for transport to the
facility. Processing consists of crushing, drying, milling,
screening, and, for a portion of the clay, a final drying
prior to packaging and shipping. A general process diagram
is given in Figure 10.
Raw Waste Load
Solid waste generated in mining montmorillonite is
overburden which is used as fill to reclaim worked-out pits.
Waste is generated in processing as dust and fines from
milling, screening, and drying operations. The dust and
fines which are gathered in bag collectors from drying
operations are hauled, along with milling and screening
fines, back to the pits as fill. Slurry from scrubbers is
sent to a settling pond with the muds being returned to
worked-out pits after recycling the water. There are no
data available on the amount of these solid wastes.
Water Use
There is no water used in the mining operations. However,
rain water and ground water collect in the pits forming a
murky colloidal suspension of the clay. This water is
pumped to worked-out pits where it settles to the extent
possible and is discharged intermittently to a nearby body
55
-------
Ul
PIT
CRUSHING
-qs
DRYER AND COOLER
WATER•
LEGEND;
ALTERNATE AIR
POLLUTION TREATMENTS
SCRUBBERS
I
RECYCLE !
POND
CLAY SLUDGE
TO MINE
MILL
AND
SCREEN
CYCLONES
—&J
BAG
COLLECTORS
t
DUST AND FINES TO MINE
.$»
ROTARY
DRYER
AND
COOLER
•PRODUCT
FIGURE 10.
FULLER'S EARTH MIMING AND PROCESSING
(MONTOORiLUDMTE)
-------
of water, except in the case of facility 3073 which uses
this water as scrubber water makeup. The estimated flow is
up to 1140 I/day (300 gpd).
Water is used in processing only in dust scrubbers. Typical
flows are:
l^lSlSi-Br.Qduct jgal/ton^
Facility 3059 3072 3073
Intake 1,930 (460) 500 (120) 143 (34)
Use:
Dust Scrubbers 1,930 (460) 500 (120) 143 (34)
Consumption:
Discharge none 150 (36) none
Evaporation plus
Landfill of Solid 1,930 (460) 350 (84) 143 (34)
Wastes
Facilities 3059 and 3073 recycle essentially 100 percent of
the scrubber water.
Waste Water Treatment
Facilities 3059 and 3073 recycle essentially 100 percent of
the scrubber water, while facility 3072 recycles only about
70 percent. Scrubber water must be kept neutral because
sulfate values in the clay become concentrated, making the
water acidic and corrosive. Facilities 3059 and 3073 use
ammonia to neutralize recycle scrubber water, forming
ammonium sulfate. Facility 3072 uses lime (Ca(OH)2), which
precipitates as calcium sulfate in the settling pond. To
keep the scrubber recycle system working, some water
containing a build-up of calcium sulfate is discharged to a
nearby creek. However, facility 3072 intends to recycle all
scrubber water by mid-1975. Mine pumpout presents a greater
problem for montmorillonite producers than for attapulgite
producers, due to the very slow settling rate of the
suspended clay. Accumulated rain and ground water is pumped
to abandoned pits for settling to the extent possible and is
then discharged. A mine pumpout sample from facility 3059
(Versar data) had a TSS of 215 mg/1. At facility 3073 the
pit water is used as makeup for the scrubber water.
Effluent and Disposal
There is no process discharge from facilities 3059 and 3073.
Facility 3072 discharges a small amount of scrubber water
after settling and lime treatment. This effluent contains
0.2 percent suspended solids and has a pH of 8. This
effluent corresponds to an average TSS of 0.3 kg/kkg
product. The settling pond muds at all three facilities are
landfilled in worked-out pits.
57
-------
KAOLIN (SIC 1455)
Kaolin is produced in mines in 17 states with Georgia
accounting for the bulk (75%) of the U.S. production. Six
kaolin mines and facilities distributed between eastern and
western U.S. were contacted representing 48 percent of the
total kaolin production in the U.S. Facilities were found
having different water usages, so two subcategories are
established for kaolin processing; wet for high grade
product, and dry, tor general purpose use.
DRY PROCESS
Process Description
The clay is mined in open pits using shovels, caterpillars,
carry-alls and pan scrapers. Trucks haul the kaolin to the
facility for processing. At facilities 3035, 3062, 3063 the
clay is crushed, screened, and used for processing to
refractory products. Processing at facility 3036 consists
of grinding, drying, classification and storage. A general
dry process diagram is given in Figure 11.
Raw Waste Load
There is no waste generated in the mining of the kaolin
other than overburden, and in the processing, solid waste is
generated from classification. No data is available on the
amount of this waste.
Water Use
There is no water used in the mining or processing of kaolin
at these four facilities. There is rainwater and ground
water which accumulates in the pits and must be pumped out.
The quantity of this mine pumpout is unknown.
Waste Water Treatment
There is no process waste water generated at any of the four
facilities, but the mine pumpout is normally sent through a
series of small settling ponds before discharge.
Effluent and Disposal
The solid waste generated is land-disposed on-site. There
is no process effluent discharged. The mine pumpout is, in
most instances, sent through a series of settling ponds to
reduce the suspended solids.
58
-------
,TRUCK
Ut
\D
OPEN PIT
DRYING
AND
CLASSIFICATION
Lp-^ RAINWATER
I GROUND WATER
t 1
SETTLING
PONDS
SOI
WA<
f
JO
3TE
• PRODUCT TO SHIPPING
*TO ON-SITE REFRACTORY
MANUFACTURING
EFFLUENT
FIGURE n
DRY KAOLIN MINING AND PROCESSING
FOR GENERAL PURPOSE USE
-------
WET PROCESS
Process Description
Sixty percent of the U.S. production of kaolin is by this
general process.
Mining of kaolin is an open pit operation using draglines or
pan scrapers. The clay is then trucked to the facility or,
in the case of facility 3025, some preliminary processing is
performed near the mine site including blunging or pug
milling, degritting, screening and slurrying to pump the
clay to the main processing facility. Subsequent operations
are hydroseparation and classification, chemical treatment
(principally bleaching with zinc hydrosulfite), filtration,
and drying (via tunnel dryer, rotary dryer or spray dryer).
For special properties, other steps can be taken such as
magnetic separation, delamination or attrition (facility
3024). Also, facility 3025 ships part of the kaolin product
as slurry (705J solids) in tank cars. A general wet process
diagram is given in Figure 12.
Raw Waste Load
Waste is generated in kaolin mining as overburden which is
stripped off to expose the kaolin deposit.
In the processing, waste is generated as underflow from
hydroseparators and centrifuges (facility 3024), and sand
and muds from filtration and separation operations. Zinc
ion is carried through to waste water from the bleaching
operations. The raw waste loads at these two facilities
are:
kg/kkg_groduct_Jlb/1000 lb)_
Waste_Material 3024 3025~
zinc 0.37 0.5
dissolved solids 8 10
suspended solids 35 100
The dissolved solids are principally sulfates and sulfites
and the suspended solids are ore fines and sand.
Water Use
Water is used in wet processing of kaolin for pug milling,
blunging, cooling, and slurrying. At facility 3024, water
is obtained from deep wells, all of which is chlorinated and
most of which is used as facility process water with no
60
-------
WATER
OPEN
PIT
PIT
PUMPOUT
ZINC
HYDROSULF1TE
BLUNGING
AND/OR
PUG MILLING
DEGRiTTING
AND
CLASSIFICATION
1
BLEACHING
AND/OR
CKEMiCAL
TREATMENT
*
FILTRATION
WATESBORN'E
TAILINGS TO
SETTLING POND
OR BY-PRODUCT
RECOVERY
I I
LIME - 6>
POND
EFFLUENT
PRODUCT
KAOLIN
1
BULK
SLURRY
70%
SLURRY
PRODUCT
FIGURE 12.
PROCESSING
FOR HIGH GRADE PRODUCT
WET KAOLIN MINING AND
-------
recycle. Facility 3025 has a company-owned ground water
system as a source and also incoming slurry provides some
water to the process none of which is recycled. Typical
water flows are:
3025
water intake 4,250 (1,020) 4,290 (1030)
process waste water 3,400 (810) 4,000 (960)
water evaporated, etc. 850 (210) 290 (70)
These facilities do not recycle their process water but
discharge it after treatment. Recycle of this water is
claimed to interfere with the chemical treatment.
Waste Water Treatment
Open pit mining of kaolin does not utilize any water.
However, when rainwater and ground water accumulate in the
pits it must be pumped out and discharged. Usually this
pumpout is discharged without treatment, but, in at least
one case, pH adjustment is necessary prior to discharge.
The facilities treat the ponds with lime to adjust pH and
remove excess zinc which has been introduced as a bleaching
agent. This treatment effects a 99.89J removal of zinc,
99. 9 % removal of suspended solids, and 80% removal of
dissolved solids.
These facilities are considering the use of sodium
hydrosulfite as bleach to eliminate the zinc waste.
Facilities with large ponds and a high freeboard have the
capability of discontinuing discharge for one or more days
to allow unusual high turbidities to decrease before
resuming a discharge.
Effluent and Disposal
solid wastes generated in kaolin mining and wet processing
are land-disposed with overburden being returned to
mined-out pits, and dust, fines, and other solids to
settling ponds.
Waste waters are in all cases sent to ponds where the solids
settle out and the water is discharged after lime treatment.
A statistical analysis was performed on five Georgia kaolin
treatment systems. Based on a 99 percent confidence level
62
-------
on the better fitting distribution of normal and logarithmic
normal the following turbidities were achieved.
Facility Turbidity, JTU or NTU
long term daily monthly
average maximum average
maximum
3024 26.4 48.2
-------
BALL CLAY (SIC 1455)
Ball clay is a plastic, white-firing clay used principally
for bonding in ceramic ware. Four ball clay producers
representing 40 percent of total U.S. ball clay production
provided data for this section. There are twelve facilities
in this category.
Process Description
After overburden is removed, the clay is mined using
front-end loaders and/or draglines. The clay is then loaded
onto trucks for transfer to the processing facility.
Processing consists of shredding, milling, air separation
and bagging for shipping. Facilities 5684 and 5685 have
additional processing steps including blunging, screening,
and tank storage for sale of the clay in slurry form, and
rotary drying directly from the stockpile for a dry
unprocessed ball clay. A general process diagram is given
in Figure 13.
Raw Waste Load
Ball clay mining generates a large amount of overburden
which is returned to worked-out pits for land reclamation.
The processing of ball clay generates dust and fines from
milling and air separation operations. These fines are
gathered in baghouses and returned to the process as
product. At the facilities where slurrying and rorary
drying are done, there are additional process wastes
generated. Blunging and screening the clay for slurry
product generates lignite and sand solid wastes after
dewatering. The drying operation uses wet scrubbers which
result in a slurry of dust and water sent to a settling
pond. There are no data available on the amount of wastes
generated in producing the slurry or the dry product, but
the waste materials are limited to fines of low solubility
minerals.
Water Use
There is no water used in ball clay mining, however, when
rain and ground water collects in the mine, there is an
intermittent discharge. Mine pumpout is either discharged
without treatment, or pumped to a settling pond before
discharge to a nearby body of water. There is usually some
diking around the mine to prevent run-off from flowing in.
There are no flow rates or water quality data available on
mine pumpout.
64
-------
PiTS
-i-
SHRED
STOCKPILE
HC
Al
«
)T
R
i
HAMMER
MiLL
CYCLONES
i
I
___*
BAG
HOUSE
I
i
AIR SEPARATOR
i
LEGEND:
ALTERNATE PROCESS ROUTES
CHEMICALS B»-
WATER 1
BLUNGER
SCREEN
SOLID VWSTE
(LIGNITE, SAND)
ROTARY
DRYER
WATER
SCRUBBERS
BAGGED
PRODUCT
BULK
PRODUCT
^ SLURRY
^^ PRODUCT
EFFLUENT
FIGURE 13.
BALL CLAY MINING AMD PROCESSING
-------
In ball clay processing, two of the facilities visited use a
completely dry process. The others produce a slurry product
using water for blunging, a product dried directly from the
stockpile with water used for wet scrubbers, and/or the dry
process product. Well water serves as the source for the
facilities which use water in their processing. Typical
flows are:
5680.
Intake total 1,130 4,300
unknown (270) (1,030)
Use:
Blunging unknown 42 (10) none
Scrubber 88 (21) 1,080 4,300
(260) (1,030)
Water used in blunging operations is consumed both as
product and evaporated from water material. Scrubber water
is impounded in settling ponds and eventually discharged.
Facilities 5685 and 5689 use water scrubbers for both dust
collection from the rotary driers and for in-facility dust
collection. Facility 5684 has only the former.
Waste Water Treatment
Mine pumpout is discharged either after settling in a pond
or sump or without any treatment.
Scrubber water at these facilities is sent to settling
ponds. In addition, facilities 5684 and 5689 treat the
scrubber water with a flocculating agent which improves
settling of suspended solids in the pond. Facility 5689 has
three ponds of a total of 1.0 hectare (2.5 acres) area.
Effluent and Disposal
There are no data available on the quality of the
intermittent mine pumpout from any of the ball clay
producers visited.
Effluent discharged from the settling pond at facility 5685
has the following parameters: a pH of 6.4 and TSS of
400 mg/1. Total suspended solids at facility 5689 averages
less than 40 mg/1. No data are available on effluent from
facility 5684.
66
-------
The amounts of process wastes discharged by these facilities
are calculated to be:
discharge,
l/kkg_of_Broduct kg/kkg of product
Ilb/1000_lbJ_
5684 88 (21)
5685 1,080 (260) 0.13
5689 834 (1,030) 0.17
There are two significant types of operations in ball clay
manufacture insofar as water use is concerned: those having
wet scrubbers, which have a waste water discharge, and those
without wet scrubbers, which have no process waste water.
There is a discrepancy in discharge flow rates since not all
the production lines in each facility have wet scrubbers.
Baghouses are also employed by this industry.
Insofar as facilities having scrubbers is concerned,
facility 5689 is exemplary in its treatment, discharging a
low concentration of TSS and a moderate total amount.
67
-------
FELDSPAR
Feldspar mining and/or processing has been sub-categorized
as follows:
(1) flotation - dry quarries - flotation processing
(2) non-flotation - dry quarries - dry crushing and classi-
fication
Feldspathic sands are included in the Industrials Sands
category in Volume I of this report.
FELDSPAR - FLOTATION
This subcategory of feldspar mining and processing is
characterized by dry operations at the mine and wet
processing in the facility. This is the most important
subcategory of feldspar, since about 73 percent of the total
tonnage of feldspar sold or used in 1972 was produced by
this process.
Wet processing is carried out in five facilities owned by
three companies. Data was obtained from all five of these
facilities (3026, 3054, 3065, 3067, and 3068). A sixth
facility is now coming into production and will replace one
of the above five facilities in 1975.
Process Description
At all five facilities, mining techniques are quite similar:
after overburden is removed, the ore is 'drilled and blasted,
followed by loading of ore onto trucks by means of power
shovels, draglines, or front end loaders for transport to
the facility. In some cases, additional break-up of ore is
accomplished at the mine by drop-balling. No water is used
in mining at any location.
The first step in processing the ore is crushing which is
generally accomplished at the facility, but may be
accomplished at the mine (Facility 3068). Subsequent steps
for all wet processing facilities vary in detail, but rhe
basic flow sheet, as given in Figure 14, contains all the
fundamentals of these facilities.
By-products from flotation include mica, which may be
further processed for sale (Facilities 3054, 3065, 3067, and
3068), and quartz or sand (Facilities 3026, 3054, and 3066).
At Facilities 3065 and 3067, a portion of the total flow to
the third flotation step is diverted to dewatering, drying,
guiding, etc., and is sold as a feldspathic sand.
68
-------
WATER
QUARRY
CRUSHER
AND
MILLS
WASHER
OR
SCRUBBER
vo
WATER
FLOTATION
AGENTS
CLASSIFICATION,
CCMDITiONiNG,
FLOTATION!
(3 REPETITIONS )
I
IRON
SOLID
WASTE
WASTE
SLURRIES
TO
POND
VENT
DEWATERiNG
AND
DRYING
9
WASTE
WATER
FIGURE 14.
FELDSPAR MINING AMD PROCESSING
(WET)
BALL
MILL
MAGNETIC
SEPARATION I
J
•PRODUCT
PRODUCT
BY -PRCCU3T
M!CA FX-OV,
-a»FiRST FLOAT
• BY-PRODUCT
SAi^O FRG.M
THIRD FLOAT
-------
Raw Waste Loads
Mining operations at the open pits result in overburden of
varying depth. The overburden is applied to land
reclamation of nearby worked-out mining areas.
Waste recovery and handling at the processing facilities is
a major consideration, as large tonnages are involved.
Waste varies from a low of 26 percent of mined ore at
Facility 3065 to a high of 53 percent at Facility 3067. The
latter value is considerably larger due to the fact that
this facility does not sell the sand from its feldspar
flotation. Most of the other facilities are able to sell
all or part of their by-product sand. Typical flotation
reagants used in this production subcategory contain
hydrofluoric acid, sulfuric acid, sulfonic acid, frothers,
amines and oils.
The raw waste data calculated from information supplied by
these facilities are:
kg/kkg_of_ore
procgssed^Ilb/1Q Q 0 _lb^
facility ore tailings and slimes fluoride
3026 270 0.22
3054 410 0.2U
3065 260 0.20
3067 530 est. 0.25
3068 350 est. 0.25
These raw wastes are generally settled in ponds or sent to
thickeners. The bulk of the solids and adsorbed organics
would then be separated from the liquid containing dissolved
fluoride and some suspended solids.
Water Use
Water is not used in the quarrying of feldspar. There is
occasional drainage from the mine, but pumpout is not
generally practiced.
Wet processing of feldspar does result in the use of quite
significant amounts of water. At the facilities visited,
water was obtained from a nearby lake, creek, or river and
used without any pre-treatment. Recycle of water is
minimal, varying from zero at several facilities to a
maximum of about 17 percent at Facility 3026. The primary
70
-------
reason for little or no water recycle is the possible build-
up of undesirable soluble organics and fluoride ion in the
flotation steps. However, some water is recycled in some
facilities to the initial washing and crushing steps, and
some recycle of water in the fluoride flotation step is
practiced at facility 3026.
Total water use at these facilities varies from 7,000 to
22,200 1/kkg of ore processed (1,680 to 5,300 gal/ton).
Most of the process water used in these facilities is
discharged. Some water is lost in tailings and drying.
This is of the order of 1 percent of the water use at
facility 3065.
The use of the process water in the flotation steps amounts
to at least one-half of the total water use. The water used
in the fluoride reagent flotation step ranges from 10 to
25 percent of the total flow depending on local practice and
sand-to-feldspar ratio. Only two of these five facilities
use any significant recycling of water. These are:
facility 3026 - 17 percent of intake (on the
average)
facility 3067 - 10 percent of intake
Waste Water Treatment
Treatment at three facilities (3054, 3065, 3068) consists of
pumping combined facility effluents into clarifiers, with
polymer added to aid in flocculation. Both polymer and lime
are added at one facility (3065). At the other two
facilities, (3026, 3067) there are two settling ponds in
series, with one facility adding alum (3026).
Measurements by EPA's contractor on the performance of the
treatment system at facility 3026, consisting of two ponds
in series and alum treatment, showed the following
reductions in concentration (mg/1):
TSS Fluoride
waste water into system 3,790 14
discharge from system 21 1.3
Effluents and Disposal
The process water effluents after treatment at these five
facilities have the following average quality
characteristics:
71
-------
facility p.H
3026 6.5-6.8 21* 8
3054 6.8 45 15*
3065 10.8* 349 23*
3067 7.5-8.0 35* 34*
3068 7-8 40-150 32
The asterisked values are Versar measurements in lieu of
facility-furnished data not available. Facility 3065 adds
lime to the treatment, which accounts for the higher than
average pH.
The average amounts of the suspended solids and fluoride
pollutants present in these waste effluent streams
calculated from the above values are given in the following
table together with the relative effluent flows.
2r.s_p_rocessed_ basis
" ~
1/kka
facility Igai/tonL iIb/l°PJLIbl -Ol2/1000_lbl
3026 14,600 0.31 0.12
(3,500)
3054 12,500 0.56 0.18
(3,000)
3065 11,000 1.1 0.25
(2,640)
3067 6,500 0.23 0.22
(1,560)
3068 18,600 0.7-2.8 0.6
(4,460)
The higher than average suspended solids content of the
effluents from 3065 and 3068 is caused by a froth carrying
mica through the thickerners to the discharges. Therefore,
the waste treatment systems in these two facilities are not
performing in an exemplary fashion. Facility 3026 is
exemplary in regard -to the levels of discharge of both
suspended solids and fluoride. The fluoride content of the
discharge is almost one-half of the raw waste load, whereas
the other facilities discharge nearly all the fluoride raw
waste. This facility uses alum to coagulate suspended
solids, which may be the cause of the reduction in fluoride.
Alum has been found in municipal water treatment studies
(references 4 and 12) to reduce fluoride by binding into the
sediment. The effectiveness of the treatment at 3026 to
72
-------
reduce suspended solids is comparable to that at facilities
3051 and 3067. All three of these facilities have exemplary
suspended solids discharge levels for this subcategory.
The treatment at facility 3054 results in little or no
reduction of fluoride, but good reduction of suspended
solids. Nothing known about this treatment system would
lead to an expectation of fluoride reduction.
The treatment at facility 3067 apparently accomplishes no
reduction of fluoride, but its suspended solids discharge is
significantly lower than average in both amount and
concentration.
Based on these conclusions, facility 3026 is exemplary in
regard to both suspended solids and fluoride discharges. In
addition, facilities 3054 and 3067 exhibit exemplary
reduction of suspended solids only.
Solid wastes are transported back to the mines as reclaiming
fill, although these wastes are sometimes allowed to
accumulate at the facility for long periods before removal.
FELDSPAR - NOW-FLOTATION
This subcategory of feldspar mining and processing is
characterized by completely dry operations at both the mine
and the facility. Only two such facilities were found to
exist in the U.S. and both were visited. Together they
represent approximately 8.5 percent of total U.S. feldspar
production. However, there are two important elements of
difference between these two operations as follows:
All of facility 3032 production of feldspar is sold for use
as an abrasive in scouring powder. At facility 3064, the
high quality orthoclase (potassium aluminum silicate) is
primarily sold to manufacturers of electrical porcelains and
ceramics.
Process Description
Underground mining is accomplished at Facility 3032 on an
intermittent, as-needed, basis using drilling and blasting
techniques. A very small amount of water is used for dust
control during drilling. At Facility 3064, the techniques
are similar, except mining is in an open pit and is carried
on for 2-3 shifts/day and 5-6 days/week depending on product
demand. Hand picking is accomplished prior to truck
transport of ore to the facility.
73
-------
At the two facilities ore processing operations are
virtually identical. They consist of crushing, ball
milling, air classification, and storage prior to shipping.
Product: grading is a function of air classification
operation. A schematic flow sheet is shown in Figure 15.
Raw Waste Loads
At Facility 3032, there are no mine wastes generated, and
only a small quantity of high-silica solids emanate from the
facility. The quantity of waste is unknown, and the
material is used as land fill. At Facility 3064, rejects
from hand picking are used as mine fill. There is very
little waste at the facility.
Water Use
At the Facility 3032 mine, water is used to suppress dust
while drilling. It is spilled on the ground and is readily
absorbed; volume is only about 230 I/day (about 60 gpd). No
water is used in facility processing at the mine. At
Facility 3064, no water is used at the mine. Facility water
is used at a daily rate of <1,900 I/day (500 gpd) to
suppress dust in the crushers. No pre-treatment is applied
to water used at either facility.
Waste water Treatment
Any waste water is spilled on the ground (Facility 3032) or
is evaporated off during crushing and milling operations
(Facility 3064). There is no waste water treatment at
either facility.
Effluents and Disposal
There are no effluents from either mine or facility
locations.
74
-------
QUARRY
I^DI ICUCDC
UKUontKo
BALL
MILLS
AIR
CLASSIFICATION
•PRODUCT
FIGURE 15.
FELDSPAR MINING AND PROCESSING
(DRY)
-------
KYANITE
Kyanite is produced in the U.S. from 3 open pit. mines, two
in Virginia and one in Georgia. In this study two of these
three mines were visited, one in Virginia, and one in
Georgia, representing approximately 75 percent of the U.S.
production of kyanite.
Process Description
Kyanite is mined in dry open quarries, using blasting to
free the ore. Power shovels are used to load the ore onto
trucks which then haul the ore to the processing facility.
Processing consists of crushing and milling, classification
and deslirning, flotation to remove impurities, drying, and
magnetic separation. Part of the kyanite is converted to
mullite via high temperature firing at 15UO°-1650°C (2800-
3000°F) in a rotary kiln. A general process diagram is
given in Figure 16.
Raw Waste Load
wastes are generated in the processing of the kyanite, in
classification, flotation and magnetic separation
operations. These wastes consist of pyrite tailings, quartz
tailings, flotation reagents, muds, sand and iron scalpings.
These wastes are greater than 50 percent of the total mined
material.
l£3/!£kg_of_kv.anite_Jlb/1000_lb
facility 3015 tailings 2,500
facility 3028 tailings 5,700
Water Use
Water is used in kyanite processing in flotation,
classification, and slurry transport of ore solids. This
process water amounts to:
76
-------
WATER
QUARRY
• i
CRUSHING
WATER
RECYCLE ,.,,
1YJ
!
i
FLOTATION
REAGENTS
™ 1 VENT
CLASSIFICATION, uArMr-nr
FLOTATION SEPARATIO^
UNDERFLOW
TAILINGS SCfl
™ WASTE
POND
m ^^ KYANITI
' " '" "" "" •• PRODUCT
1
fc ROTARY fc MULLITI
KILN PRODuC
LPINGS
FIGURE 16.
KYANITE MINING AND PROCESSING
-------
facility 3015 29,200 (7,000)
facility 3028 87,600 (21,000)
The process water is recycled, and any losses due to
evaporation and pond seepage are replaced with make-up
water. Make-up water for facility 3028 is used at a rate of
4,200,000 I/day (0.288 mgd) and facility 3015 obtains
make-up water from run-off draining into the settling pond
and also from an artesian well.
Waste Water Treatment
Process water used in the several beneficiation steps is
sent to settling ponds from which clear water is recycled to
the process. There is total recycle of the process water
that is not lost through evaporation and pond seepage.
Effluent and Disposal
There is no deliberate discharge of process water from
facility 3015. The only time pond overflow has occurred at
facility 3015 was after an unusually heavy rainfall.
Facility 3028 has occasional pond overflow, usually
occurring in October and November.
The solid waste generated in kyanite processing is
land-disposed after removal from settling ponds. An
analysis of pond water at facility 3015 showed low values
for BOD5 (2 mg/1) and oil and grease (4 mg/1). Total
suspended solids were 11 mg/1 and total metals 3.9 mg/1,
with iron being the principal metal. No analyses were
available on the occasional overflow at facility 3028.
78
-------
MAGNESITE
There is only one known U.S. facility that produces magnesia
from naturally occurring magnesite ore. This facility,
facility 2063, mines and beneficiates magnesite ore from
which caustic and dead burned magnesia are produced. The
present facility consists of open pit mines, heavy media
separation (HMS) and a flotation facility.
Process Description
All mining operations are accomplished by the open pit
method. The deposit is chemically variable, due to the
interlaid horizons of dolomite and magnesite, and megascopic
identification of the ore is difficult. The company has
devised a selective quality control system to obtain the
various grades of ore required by the processing facilities.
The pit is designed with walls inclined at 60°, with 6 m (20
ft) catch benches every 15 m (50 ft) of vertical height.
The crude ore is loaded by front end loaders and shovels and
then trucked to the primary crusher. The quarry is located
favorably so that there is about 2 km (1.25 mi) distance to
the primary crusher. About 2260 kkg/day (2500 tons/day) of
ore are crushed in the mill for direct firing and
beneficiation. There is about 5 percent waste at the
initial crushing operation which results from a benefication
step. The remainder of the crusher product is further
processed thru crushing, sizing and beneficiating
operations.
The flow of material through the facility, for direct
firing, follows two major circuits: (1) the dead burned
magnesite circuit, and (2) the light burned magnesite
circuit. In the dead burned magnesite circuit, the ore is
crushed to minus 1.9 cm (3/4 in) in a cone crusher. The raw
materials are dry ground in two ball mills that are in
closed circuit with an air classifier. The minus 65 mesh
product from the classifier is transported by air slides to
the blending silos. From the silos the dry material is fed
to pug mills where water and binding materials are added.
From the pug mills the material is briquetted, dried, and
stored in feed tanks ahead of rotary kilns. The oil or
natural gas fired kilns convert the magnesite into dense
magnesium clinker of various chemical constituents,
depending upon the characteristics desired in the product.
After leaving the kiln, the clinker is cooled by an air
quenched rotary or grate type coolers, crushed to desired
sizes, and stored in large storage silos for shipment.
In the light burned magnesite circuit, minus 1.9 cm (3/4 in)
magnesite is fed to two Herreshoff furnaces. By controlling
the amount of liberated CO2 from the magnesite a caustic
79
-------
oxide is produced from these furnaces. The magnesium oxide
is cooled and ground in a ball mill into a variety of grades
and sizes, and is either bagged or shipped in bulk.
Magnesite is beneficiated at facility 2063 by either heavy
media separation (HMS) and/or froth flotation methods. In
the HMS facility, the feed is crushed to the proper size,
screened, washed and drained on a vibratory screen to
eliminate the fines as much as possible. The screened feed
is fed to the separating cone which contains a suspension of
finely ground ferro-silicon and/or magnetite in water,
maintained at a predetermined specific gravity. The light
fraction floats and is continuously removed by overflowing a
weir. The heavy particles sink and are continuously removed
by an airlift.
The float weir overflow and sink airlift discharge go to a
drainage screen where 90 percent of the medium carried with
the float and sink drains through the screen and is returned
to the separatory cone. The "float" product passes from the
drainage section of the screen to the washing section where
the fines are completely removed by water sprays. The solid
wastes from the wet screening operations contain -0.95 to
+3.8 cm (-3/8 to +1-1/2in) material which is primarily used
for the construction of settling pond contour. The fines
from the spray screen operations, along with the "sink" from
the separating cone, are sent into the product thickener.
In the flotation facility, the feed is crushed, milled, and
classified and then sent into the cyclone clarifier. Make-
up water, along with the process recycled water, is
introduced into the cyclone classifier. The oversize from
the classifier is ground in a ball mill and recycled back to
the cyclone. The cyclone product is distributed to the
rougher flotation and the floated product is then routed to
cleaner cells which operate in series. The flotation
concentrate is then sent into the product thickener. The
underflow from this thickener is filtered, dried, calcined,
burned, crushed, screened and bagged for shipment.
The tailings from the flotation operation and the filtrate
constitute the waste streams of these facilities and are
sent into the tailings thickener for water recovery. The
overflows from either thickener are recycled back to
process. The underflow from the tailings thickener
containing about 40 percent solids is impounded in the
facility. A simplified flow diagram for this facility is
given in Figure 17.
Raw Waste Loads
The raw waste from this facility consists of the underflow
from the tailings thickeners and it includes about
80
-------
ORE
J_
CRUSHERS
00
0/0
FINES
TO
WftSTE
15%
TO
KILN
x50'
-30
RECYCLED
WATER
HEfl/Y
CRU5HFR — — rin MEDIA
LKUoMUt — • €» SEPARATION
PLAMT
I )/o -a
SOLID
WASTE
FLOTATION
AGENT
>% 1
MAKE-UP WATER
UNDERFLOW
40% SOLIDS
TO SETTLING POND
FIGURE 17
MAGNESITE MINING AND PROCESSING
VENT
BAG
HOUSE
CRUSHERS
ROD MILLS
AND
CLASSIFIERS
'
1 L_
OVERFLOW
»
ROUGHER
AND
CLEANER
CELLS
!
— — ®s
1?
CONCENTRATE
THICKENER
RECYCLE
TAILS^GS
THICKENER
_j
ICffll , - , - i - r--i -- -
VACUUM
FILTERS
1
FILTRATE
DRY NG,
CALC1 v';M3,
BUH?' IN 3,
CRUSHING,
SCrtEENING
KACf.'ESfA
PRODUCT
-------
40 percent suspended solids amounting to 590,000 kg/day
(1,300,000 Ib/day) .
Facility Water Use
This facility's fresh water system is serviced by eight
wells. All wells except one are hot water wells, 50 to 70°c
(121° to 160°F) . The total mill intake water is 2,200,000
I/day (580,000 gal/day), 88 percent of which is cooled prior
to usage. The hydraulic load of this facility is given
below:
.,
process "water ™o~ref ine the
product 163,000 (U3,000)
road dust control 227,000 (60,000)
sanitary 11,360 ( 3,000)
tailing pond evaporation 492,000 (130,000)
tailing pond percolation 757,000 (200,000)
evaporation in water sprays,
Baker coolers & cooling towers 545,000 (144,000)
No process waste waters are discharged out of the property
at this facility. There is no mine water pumpout at this
facility.
Waste Water Treatment.
The waste stream at this facility is the underflow of the
tailings thickener which contains large quantities of solid
wastes. To aid the flow, make-up water is added to this
waste stream and then discharged into the tailings pond.
The estimated area of this pond is 15 hectares (37 acres) .
The estimated evaporation at this area is 21 cm/yr (54
in/yr) and the annual rainfall is 2.4 cm/yr (6 in/yr) . The
waste water is, therefore, lost about 40 percent by
evaporation and about 60 percent by percolation. No stream
discharge from the mill is visible in any of the small
washes in the vicinity of the tailings pond, and also, no
green vegetative patches, that would indicate the presence
of near surface run-off s, were visible. The tailings pond
is located at the upper end of an alluvial fan. This
material is both coarse and angular and has a rapid perco-
lation rate. This could account for the lack of run-off and
the total recharge of the basin.
Effluent
As all process waters at facility 2063 are either recycled
or lost by evaporation and percolation, there is no process
water effluent discharge out of this property.
82
-------
SHALE
Shale is a consolidated sedimentary rock composed chiefly of
clay minerals, occurring in varying degrees of hardness.
Shales and common clays are for the most part used by the
producer in fabricating or manufacturing structural clay
products (SIC 3200) so only shale mining and processing is
discussed here. Less than 10 percent of total clay and
shale output is sold outright. Therefore, for practical
purposes, nearly all such mining is captive to ceramic or
refractory manufactures. Shale is mined in open pits using
rippers, scrapers, bulldozers, and front-end loaders for
removal of the shale from the pit. Blasting is needed to
loosen very hard shale deposits. The shale is then loaded
on trucks or rail cars for transport to the facility.
There, primary crushing, grinding, screening, and other
operations are used in the manufacture of many different
structural clay products. A general process diagram is
given in Figure 18. Solid waste is generated in shale
mining as overburden which is used as fill to reclaim
mined-out pits. Since ceramic processing is not covered, no
processing waste is accounted for.
Water Use
There is no water used in shale mining, however, due to
rainfall and ground water seepage, there can be water which
accumulates in the mines and must be removed. Mine pumpout
is intermittent depending on rainfall frequency and
geographic location. In many cases, facilities will build
small earthen dams or ditches around the pit to prevent
inflow of rainwater. Also shale is, in most cases, so hard
that run off water will not pickup significant suspended
solids. Flow rates are not generally available for mine
pumpout.
Waste Water Treatment
There is no waste water treatment necessary for shale mining
and processing since there is no process water used. When
there is rainfall or ground water accumulation, this water
is generally pumped out and discharged to abandoned pits or
streams.
Effluent and Disposal
Mine pumpout is discharged without treatment. There is no
other effluent.
83
-------
COARSE
oo
*«
SHALE
p|T
PRIMARY
CRUSHER
GRIND
SCREEN
1
PIT
PUMPOUT
PRODUCTS
FIGURE 18.
SHALE MINING AND PROCESSING
-------
APLITE
Aplite is found in quantity in the U.S. only in Virginia and
is mined and processed by only two facilities, both of which
are discussed below.
Process Description
The deposit mined by facility 3016 is relatively soft and
the ore can be removed with bulldozers, scrapers, and
graders, while that mined by facility 3020 requires blasting
to loosen from the quarry. The ore is then loaded on trucks
and hauled to the processing facility.
Facility 3016 employs a wet process consisting of wet
crushing and grinding, screening, removal of mica and heavy
minerals via a series of wet classifiers, dewatering and
drying, magnetic separation and final storage prior to
shipping.
Facility 3020 processing is dry, consisting of crushing and
drying, more crushing, screening, magnetic separation and
storage for shipping. However, water is used for wet
scrubbing to control air pollution. A process flow diagram
is given in Figure 19 depicting both processes.
Raw Waste Load
Mining waste is overburden and mine pumpout. The processing
wastes are dusts and fines from air classification, iron
bearing sands from magnetic separation, and tailings and
heavy minerals from wet classification operations. The
latter wastes obviously do not occur at the dry facility.
Materials ton/r]_ iib/100()_!b.l_
facility 3016 tailings and 136,000 1,000
(wet) heavy minerals (150,000)
and fines
facility 3020 dust and fines 9,600 175
(dry) (10,600)
Other, non-waterbome wastes come from the magnetic
separation step at facility 3020.
85
-------
00
LEGEND.
— DRY
PWITFCC
— WET PROCESS
— .»
PRI
UFO
t
!
•i
i
i
i
i
ICUUU
joMirji
FN
J
I
j
SCREENING
i
i
1
1
A
P|L
t
avikio
UK i ii'tv?
— .fie
CYCLONE
1
1
t
W«TrP _ ,*»_
t
CRl
CPC
OOP
—
JSH
EEh
NG
1 i » t ^
cpoi iRprrpc
§
t r\ i
CLASSIFY -
-*
^<>
4.O
DUST, FINES
QiCY
Oir 1
VENT
DRYii'JG
AND
SCREENING
.
MAGNETiC
SEPARATION
f ! !
i
i
i
i
• *
1 & IRON SANDS
1
T TO LANDFILL
- -y flp; ITF
"^ PRODUCT
.^.flp- A?L!TE
PRODUCT
£ | OR BEACH SAND £
...If, . H
POND
1
|
POND
[
FIGURE 19.
APLITE MINING AND PROCESSING
EFFLUENT
-------
Water Use
Water is used at facility 3020 (dry process) only for wet
scrubbers which cut down on airborne dust and fines. This
water totals 1,230,000 I/day (321,000 gpd) with no recycle.
There is occasional mine pumpout.
Water is used at facility 3016 for crushing, screening and
classifying at a rate of 38,000,000 I/day (10,000,000 gpd)
which is essentially 100% recycled. Dust control requires
about 1,890,000 I/day (500,000 gpd) of water which is also
recycled. Any make-up water needed due to evaporation
losses comes from the river. The amount was not disclosed.
There is no mine pumpout at facility 3016 and any surface
water which accumulates drains to a nearby river.
The facility water use in this industry can be summarized:
process use;
scrubber or dust
control
crush, screen,
classify
net discharge (less
mine pumpout)
mine pumpout
make-up water
intake
1/kkg product
3016
3,600 (870)
12,700 (3,010)
approx. 0
0
not given
3020
5,900 (1,420)
0
5,900 (1,120)
not given
5,900 (1,420)
Waste Water Treatment
The waste water generated in these aplite operations is sent
to tailings ponds where solids are allowed to settle. The
scrubber water from facility 3020 is discharged after
settling while the occasional mine pumpout is discharged
without settling. The water from the wet process facility
3016 is essentially 100% recycled to the process. Every few
years, when the pond level becomes excessive, facility 3016
discharges from the pond to a river. When this occurs, the
pond is treated with alum to lower suspended solids levels
in the discharge. Likewise, when suspended solids levels
are excessive for recycle purposes, the pond is also treated
with alum. There is no other water loss from facility 3016
except for evaporation and pond seepage.
87
-------
Effluent and Disposal
Facility 3020 discharges effluent arising from wet scrubber
operations to a creek after allowing settling of suspended
solids in a series of ponds. Aplite clays represent a
settling problem in that a portion of the clays settles out
rapidly but another portion stays in suspension for a long
time, imparting a milky appearance to the effluent. The
occasional mine pumpout due to rainfall is discharged
without treatment.
Facility 3016 recycles water from the settling ponds to the
process with only infrequent discharge to a nearby river
when pond levels become excessive (every 2 to 3 years).
This discharge is state regulated only on suspended solids
at 649 mg/1 average, and 1000 mg/1 for any one day. Actual
settling pond warer analyses have not been made.
The solid wastes generated in these processes are
land-disposed, either in ponds or as land-fill, with iron
bearing sands being sold as beach sand.
88
-------
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE
There are 33 known facilities in the U.S. producing talc,
steatite, soapstone and pyrophyllite. Twenty-seven of these
facilities use dry grinding operations, producing ground
products, two utilize log washing and wet screening
operations producing either crude talc or ground talc and
four are wet crude ore beneficiation facilities, three using
froth flotation and one heavy media separation techniques.
Process Description of Dry Grinding Operations
In a dry grinding mill, the ore is batched in ore bins and
held until a representative ore sample is analyzed by the
laboratory. Each batch is then assigned to a separate ore
silo, and subsequently dried and crushed in a crushing
circuit. The ore, containing less than 12X moisture is
reclaimed from these storage silos and sent to fine dry
grinding circuits in the mill. In the pebble mill (Hardinge
circuit), which includes mechanical air separators in closed
circuit, the ore is ground to minus 200 mesh rock powder.
Part of the grades produced by this circuit are used
principally by the ceramic industry; the remainder is used
as feed to other grinding or classifying circuits. In a few
facilities, some of this powder is introduced into the fluid
energy mill to manufacture a series of minus 325 mesh
products for the paint industry.
Following grinding operations, the finished grades are
pumped, in dry state, to product bulk storage silos. The
product is reclaimed from these silos, as needed, and either
pumped to bulk hopper cars or to the bagging facility where
it is packed in bags for shipment. A generalized process
diagram for a dry grinding mill is given in Figure 20.
There is no water used in dry grinding facilities;
therefore, there is no generation of water-borne pollutants
by these facilities. Bag housed collectors are used
throughout this industry for dust control. The fluid energy
mills use steam. The steam generated in boilers is used in
process and vented to atmosphere after being passed through
a baghouse dust collector to remove dust product from the
steam. The waste streams emanating from the boiler
operations originate from conventional hot or cold lime
softening process and/or zeolite softening operations,
filter backwash, and boiler blowdown wastes which are
addressed under general water guidelines in Section IX of
this report.
Even though these facilities do not use water in their
process, some of them do have mine water discharge from
their underground mine workings.
89
-------
TALC ORE"
JAY/
AND
CONE
CRUSHERS
WET
ORE
BIN
FINE
CRUSHING
AND DRYING
CIRCUIT
DRY
ORE
SILOS
PEBBLE
MILL
GRINDING
CIRCUIT
COARSE ->
MATERIAL
•^PRODUCT
STEAM
OR
COMPRESSED
AIR
vo
o
FLUID
ENERGY
GRINDING
CIRCUIT
i
DRY
COLLECTOR
"RODUCTS
•PRODUCT
FIGURE 20.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE MINING AND PROCESSING
(DRY)
-------
Process Description of Log Washing and Wet Screening
At log washing facility 2034 and wet screening
facility 2035, the water is used to wash fines from the
crushed ore. In either facility, the washed product is next
screened, sorted and classified. The product from the
classifier is either shipped as is or it is further
processed in a dry grinding mill to various grades of
finished product.
At facility 2034 wash water is sent into a hydroclone system
for product recovery. The slimes from the hydroclone are
then discharged into a settling pond for evaporation and
drying. At facility 2035, the wash water, which carries the
fines, is sent directly into a settling pond.
The wet facilities in this subcategory are operational on a
six-month per year basis. During freezing weather, these
facilities are shut down. Stockpiles of the wet facility
products are accumulated in summer and used as source of
feed in the dry grinding facility in winter. Simplified
diagrams for facilities 2034 and 2035 are given in Figures
21 and 22 respectively.
Raw Waste Loads
The raw waste from facility 2034 consists of the slimes from
the hydroclone operation, that of facility 2035 is the
tailings emanating from the wet screening operation and the
slimes from the classifiers. Neither company keeps records
on the quantity of the wastes, since no water is discharged.
Facility Water Use
Both facilities are supplied by water wells on their
property. Essentially all water used is process water.
Facility 2034 has a water intake of 182,000 I/day
(48,000 gal/day) and facility 2035 has a water intake of
363,000 I/day (96,000 gal/day).
Waste Water Treatment
The waste streams emanating from the washing operations are
sent into settling ponds. The ponds are dried by
evaporation and seepage. In facility 2035, when the ponds
are filled with solids, they are harvested for reprocessing
into saleable products.
Effluent
There is no discharge out of these properties.
91
-------
to
ORE
WATER
LOG
WASHER
VIBRATING
SCREEN
OVERSIZE TO
STOCKPILE
AND MILLiNG
SCREW
CLASSIFIER
- FINES
HYDROCLONE
?
SLIMES TO
SETTLING FCfCD
-«> PRODUCT
FIGURE 21.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE MINING AND PROCESSING
(LOG WASHING PROCESS)
-------
CRUDE ORE -—CJ
VO
OJ
WATER
WET
SCREENING
CLASSIFICATION
TAILINGS TO POND
SORTING
SLIMES OVERSIZE
TO POND TO DUMP
STOCKPILES
AND
MILLS
PRODUCT
FIGURE 22.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE MINING AND PROCESSING
(WET SCREENING PROCESS)
-------
Mine Water Discharge
Underground mine workings intercept numerous ground water
sources. The water from each underground mine is directed
through ditches and culverts to sumps at each mine level.
The sumps serve as sedimentation vessels and suctions for
centrifugal pumps which discharge this water to upper level
sumps or to the.surface. In some mines, a small portion of
the pump discharge is diverted for use as drill wash water
and pump seal water; the remainder is discharged into a
receiving waterway. The disposition and quantities of mine
discharges are given as follows:
Liguid
I/day"
2037
2038
2039
2040
2041
2042
2043
ES ID9/1
8.3 4, 9
7.8
8.1
7.2-8.5 15
8.7
7.8
7.6
28
1,020,000
(270,000)
878,000
(232,000)
1,900,000
(507,000)
1,100,000
(300,000)
49,200
(13,000)
496,000
(131,000)
76,000
(20,000)
Pumped to a
swamp
Pumped to a
swamp
Open ditch
Settling basin
than to a brook
Settling basin
then to a brook
Settling basin
then to a brook
Settling basin
then to a river
Mine Water Treatment
In mines 2040, 2041, 2042 and 2043, the water from each mine
is directed through ditches and culverts to sumps at each
mine level. The sumps serve as sedimentation vessels and
suctions for centrifugal pumps which discharge this water to
upper level settling basins. The overflows from these
basins are discharged into a receiving stream. The
remaining mines employ no surface settling basins. The
water from the underground sump is directly discharged into
a receiving ditch, waterway or mine without further
settling.
94
-------
Effluent Composition
No information was available on mines 2037 and 2038. The
significant constituents, however, in the remaining mine
effluents are reported to be as follows:
Waste Material
Mine Number 2036 2039
TSS, mg/1 9 3 <20
Iron, mg/1 0.08 0.05
pH min-max 7,5-7.8 7.0-7.3 7.2-8.5
Process Description of Flotation and Heavy Media Separation
Facilities
All four facilities in this subcategory use either flotation
or heavy media separation techniques for upgrading the
product. In two of the facilities (2031 and 2032) the ore
is crushed, screened, classified and milled and then taken
by a bucket elevator to a storage bin in the flotation
section. From there it is fed to a conditioner along with
well and recycled water. The conditioner feeds special
processing equipment, which then sends the slurry to a pulp
distributor. In facility 2031, the distributor splits the
conditioner discharge over three concentrating tables from
which the concentrates, the gangue material, are sent to the
tailings pond. The talc middlings from the tables are then
pumped to the flotation machines. However, in facility
2032, the distributor discharges directly into rougher
flotation machines. A reagent is added directly into the
cells and the floated product next goes to cleaning cells.
The final float concentrate feads a rake thickener which
raises the solids content of the flotation product from 10
to 35 percent. The product from thickener is next filtered
on a rotary vacuum filter and water from the filter flows
back into the thickener. The filter cake is then dried and
the finished product is sent into storage bins. The
flotation tailings, along with thickener overflow, are sent
to the tailings pond. A simplified flow diagram is given in
Figure 23.
Facility 2033 processes ores which contain mostly clay and
it employs somewhat different processing steps. In this
facility, the ore is scrubbed with the addition of liquid
caustic to raise the pH, so as to suspend the red clay. The
scrubbed ore is next milled and sent through thickening,
flotation and tabling. The product from the concentrating
tables is acid treated to dissolve iron oxides and other
possible impurities. Acid treated material is next passed
through the product thickener, the underflow from which
contains the finished product. The thickener underflow is
95
-------
TALC ORE
CRUSHiNG,
DSYIN'G,
GRihiDJNG
—
WATER
I
CONDITIONER
*
1
1
[
-W
1
I
!
PL'LP
DISTRIBUTOR
AND
CONCENTRATING
TA3LES
1
I
-*
FLOTATION
REAGENTS
J
DiSTRSSUTOR
AND
FLOTATION
CELLS
1
^
THICKENER
AND
FILTER
1
-
DRYER
•PRODUCT
I I
LEGEND:
ALTERNATE PROCESSES
i
TAILINGS BASIN
CLARIFICATION
EASiNS
T
EFFLUENT
FIGURE 23.
TALC MINING AND PROCESSING
(FLOTATION PROCESS)
-------
filtered, dried, ground and bagged. The waste streams
consist of the flotation tailings, the overflow from the
primary thickener and the filtrate. A generalized flow
diagram is given in Figure 24.
Facility 2044 uses heavy media separation (HMS) technique
for rhe benef iciation of a portion of their product. At
this facility, the ore is crushed in a jaw crusher and
sorted. The minus 2 inch material is dried before further
crushing and screening operations whereas the plus 5.1 cm (2
in) fraction is crushed, screened and sized as recovered
from the primary crushing stage. The minus 3 to plus 20
mesh material resulting from the final screening operation
is sent to HMS facility for the rejection of high silica
grains. The minus 20 mesh fraction is next separated into
two sizes by air classification.
Facility 2044 uses a wet scrubber on their #1 drier for dust
control. On drier #2 (product drier) a baghouse is used and
the dust recovered is marketed. A simplified process flow
diagram for this facility is given in Figure 25.
Raw Waste Loads
In facilities 2031 and 2032, the raw waste consists of the
mill tailings emanating from the flotation step. In
facility 2033, in addition to the mill tailings, the waste
contains the primary thickener overflow and the filtrate
from the product filtering operation. In facility 2044 the
raw waste stream is the composite of the HMS tailings and
the process waste stream from the scrubber. The average
values given are listed as follows:
Waste Material JS9/lS}£eLof_fi°£ation_p^oduct__{lb/1000
N 2031 ~ 204
TSS 1800 1200-1750 800 26
Facility Water Use
The flotation mill at facility 2031 consumes water, on the
average, 25,400 1/kkg (6,070 gal/ton) of product. This
includes 200 1/kkg product of non-contact cooling water
(48 gal/ton) which is used in cooling the bearings of their
crushers.
Facility 2032 consumes 17,200 1/kkg (4150 gal/ton) product;
40 percent of which may be recycled back to process, after
clarification. Recycled water is used in conditioners and
as coolant in compressor circuits and for several other
miscellaneous needs.
97
-------
CRUDE CRE«
LIOUiD
CA'JSTIC
WATER
AND
REAGENTS
TAILINGS
SULFUROUS
ACID
1
BALL WILL. ! »
THiCKENER j
f 20%
CONDITIONER
i
m
t
*3>
FLOTATION
CELLS
RECYCLE 1 «
V*
LiWE f£r<
-<.
*
TABLES
r
SUMP
-*
FILTERS '
'1
DRYER,
GRINDER,
BAGGER
-PRODU'
TO SETTLING POND
RGURE 24.
TALC MINING AND PROCESSING
(IMPURE ORE)
-------
VJ5
WATER B>
PRIMARY
CRUSHER
1
DRYER
1
WET
SCRUBBER
I
SETTLING
POND
1
CRUSHING
AND
SCREENING
1
|
PEBBLE
MILLS
AIR
CLASS
IF1ER
-^ PYROPHYLLITI
| PRODUCT
WATER
A
HEAVY
MEDIA
PLANT
\
?
SCREENING
AKD
SCREW
CLASSIFIERS
CRUSHING
SCREENING
WET SAND
BY-PRODUCT
ANDALUSiTE
— " BY-PRODUCT
^ PYROPHILLITE
** BY-PRODUCT
EFFLUENT
WASTE
TO SETTLING POND
FIGURE 25.
PYROPHYLLITE MINING AND PROCESSING
(HEAVY MEDIA SEPARATION)
-------
Facility 2033 consumes 16,800 1/kkg (4000 gal/ton) product;
20 percent of which is recycled back to process from the
primary thickener operation. Facility 2041 consumes on the
average 1/kkg (1,305 gal/ton) total product. The hydraulic
load of these facilities is summarized as follows:
Consumption
at Facility No. 2031 2032 2033 2034
Process 730,000 2,200,000 757,000 1,135,000
consumed (192,000) (583,000) (200,000) (300,000)
Non-contact 37,000 --- 54,000 ---
cooling (9,600) (14,000)
Facility Waste Treatment
At facility 2031, th?. mill tailings are pumped into one of
the three available settling ponds. The overflow from these
settling ponds enters by gravity into a common clarification
pond. There is no point discharge from this clarification
pond. The tailings remain in the settling ponds and are
dried by natural evaporation and seepage.
At facility 2032, the mill tailings are pumped uphill
through 3000 feet of pipe to a pond of 34,000,000 1
(9,000,000 gal) in capacity for gravity settling. The
overflow from this pond is treated in a series of four
settling lagoons. Approximately 40 percent of the last
lagoon overflow may be sent back to the mill and the
remainder is discharged to a brook near the property.
In facility 2033, the filtrate, with a pH of 3.5-4.0, the
flotation tailings with a pH of 10-10.5 and the primary
thickener overflow are combined, and the resulting stream,
having a pH of 4.5-5.5, is sent to a small sump in the
facility for treating. The effluent pH is adjusted by lime
addition to a 6.5-7.5 level prior to discharge into the
settling pond. The lime is added by metered pumping and the
pH is controlled manually. The effluent from the treating
sump is routed to one end of a "U" shaped primary settling
pond and is discharged into a secondary or back-up pond.
The total active pond area is about 0.8 hectare (2 acres).
The clarification pond occupies about 0.3 hectare
(0.75 acres) . The back-up pond (clarification pond)
discharges to an open ditch running into a nearby creek.
The non-contact cooling water in facilities 2031 and 2033 is
discharged without treatment. Facility 2044 uses a 1.6
hectare (4 acres) settling pond to treat the waste water;
the overflow from this pond is discharged into the river.
It has been estimated that the present settling pond will be
100
-------
filled within two years' time. This company has leased a
new piece of property for the creation of a future pond.
Effluent Composition
As all process water at facility 2031 is impounded and lost
by evaporation, there is no process water effluent out of
this property. Facility 2035 a washing facility also has no
discharge.
At facilities 2032, 2033, and 2044, the effluent consists of
the overflow from their clarification or settling pond. The
significant constituents in these streams are reported to be
as follows:
Waste_Materia^
2032 ___________ 2033 2044
pH 7.2-8.5 5.6 7.0
TSS, mg/1 <20(26)* 80 (8)** 100
*Contractor verification
**More recent data by contractor
The average amounts of TSS discharged in these effluents
were calculated from the above data to be:
product
2032 <0.34
2033 0.29
2044 0.50
Exemplary performance of waste water treatment was attained
by facilities 2032 and 2044. Also facility 2031 is a
special case in that it has no discharge by virtue of
evaporation and seepage of all waste water.
101
-------
NATURAL ABRASIVES
Garnet and tripoli are the major natural abrasives mined in
the U.S. Other minor products, e.g. emery and special
silica-stone products, are of such low volume production
(2,500-3,000 kkg/yr) as to be economically insignificant and
pose no significant environmental problems. They will not
be considered further,
GARNET
Garnet is mined in the U.S. almost solely for use as an
abrasive material. Two garnet abrasive producers,
representing more than 80 percent of the total U.S.
production, provided the data for this section. There are 4
facilities in the U, S. producing garnet, one of which
produces it only as a by-product.
Process Description
The two garnet operations studied are in widely differing
geographic locations, and so the garnet deposits differ, one
being a mountain schists (3071), and the other an alluvial
deposit (3037).
Facility 3071 mines by open pit methods with standard
drilling and blasting equipment. The ore is trucked to a
primary crushing facility and from there conveyed to the
mill where additional crushing and screening occurs. The
screening produces the coarse feed to the heavy-media
section and a fine feed for flotation.
The heavy-media section produces a coarse tailing which is
dewatered and stocked, a garnet concentrate, and a middling
which is reground and sent to flotation. The garnet
concentrate is then dewatered, filtered/ and dried.
Facility 3037 mines shallow open pits, stripping off
overburden, then using a dragline to feed the garnet-bearing
earth to a trumble (heavy rotary screen). Large stones are
recovered and used for road building or to refill The pits.
The smaller stones are trucked to a jigging operation, also
in the field, where the heavier garnet is separated from all
impurities except some of the high density kyanite. The raw
garnet is -then trucked to the mill. There the raw garnet is
dried, screened, milled, screened and packaged. Figure 26
gives the general flow diagram for these operations.
102
-------
WATER —p»
COARSE
QUARRY
CRUSHiNG
HEAVY
f.'.EDIA
PLANT
WATER-
.RECYCLE
TRUM1LE
LAHGE
STQK'ES
FOR
FILL
WATER-
JIG
SETTLING
POND
EFFLUENT
A • RECYCLE
DEIWERSNG
SCREEN
WATER
COARSE TASLIMGS I
SOLD AS ROAD GRAVEL A
DRYING
FLOTATION
RECYCLE
THICKENER
SETTLING
PONDS
EFFLUENT
FIGURE 26.
GARNET MINING AMD PROCESSING
•PRODUC
SCREENING
-------
Raw Waste Load
Solid waste is generated in garnet mining as overburden
which is used for reclaiming worked-out pits. Large stones
recovered from in-the-field screening operations at facility
3037 are also used to refill pits or for road building.
In the processing of the garnet ore, solid waste in the form
of coarse tailings is generated from the heavy-media
facility at facility 3071. These tailings are stocked and
sold as road gravel. The flotation underflow at facility
3071 consisting, of waste fines, flotation reagents and water
is first treated to stabilize the pH and then is sent to a
series of tailings ponds. In these ponds, the solids settle
and are removed intermittently by a dragline and used as
landfill.
The categories of raw wastes generated at these facilities
are therefore:
3037 3071
large stones and yes yes
coarse tailings
flotation fines and no yes
reagents
fine tailings yes no
Water Use
Untreated surface water is pumped to the pits at facility
3037 for initial washing and screening operations and for
make-up. This pit water.is recycled and none is discharged
except as ground water. Surface water is also used for the
jigging operation, but is discharged after passage through a
settling pond. No data is available regarding the quantity
of water used in these operations.
At facility 3071, water is collected from natural run-off
and mine drainage into surface reservoirs, and it is used in
both the heavy media facility and in flotation. This
process water amounts to approximately 380-760 1/min
(100-200 gpm) and is about 50 percent recycled.
Effluent flow varies seasonally from a springtime maximum of
570 1/min (150 gpm) to a minimum in summer and fall.
104
-------
The summarized average water flow data given below is based
on 50 percent recycle at facility 3071:
3037
washing and screening amount not known none
heavy media separation
and flotation none 24,600 (5,900)
jigging amount not known none
discharge of wastes. jigging water only 12,300 (3,000)
Waste Water Treatment
Facility 3037 recycles untreated pit water used in screening
operations, and sends water from jigging operations to a
settling pond before discharging it back into the creek.
Waste water from flotation underflow at facility 3071 is
first treated with caustic to stabilize the 'pH which was
acidified from flotation reagents. Then the underflow is
sent to a series of tailings ponds. The solids settle out
into the ponds and the final effluent is discharged. Water
from the dewatering screen is recycled to the heavy media
facility.
Effluent and Disposal
Effluent arising from flotation underflow at facility 3071
is discharged. The pH is maintained at 7. The suspended
solids content averaged 25 mg/1.
Effluent from jigging operations at facility 3037 is
discharged after passage through a settling pond.
105
-------
TRIPOLI
Tripoli encompasses a group of fine-grained, porous, silica
materials which have similar properties and uses. These
include tripoli, amorphous silica and rottenstone. All four
producers of tripoli provided the data for this section.
Process Description
Amorphous silica (tripoli) is normally mined from
underground mines using conventional room-and-pillar
•techniques. There is at least one open-pit mine (5688) .
Trucks drive into the mines where they are loaded using
front-end loaders. The ore is then transported to the
facility for processing. Processing consists of crushing,
screening, drying, milling, classifying, storage, and
packing for shipping. A general process diagram is given in
Figure 27. At one facility only a special grade tripoli (a
minor portion of the production, value approximately
$250,000/year) is made by a unique process using wet-milling
and scrubbing.
Raw Waste Load
Both facilities report no significant waste in processing.
Any dust generated in screening, drying, or milling
operations is gathered in cyclones and dust collectors and
returned to the process as product.
Mining generates a small amount of dirt which is piled
outside the mine and gravel which is used to build roads in
the mining areas. The product itself is of a very pure
grade so no other mining wastes are generated.
Water Use
There is no water used in mining, nor is there any ground
water or rain water accumulation in the mines.
The standard process is a completely dry process.
106
-------
BAG
HOUSES
CYCLONES
MINE
j
CRUSH
I
AIR
CLASSIFY
PRODUCT
FIGURE 27.
TRIPOLI
BY THE
MINING
AND PROCESSING
STANDARD PROCESS
-------
DIATOMITE MINING
There are nine diatomite mining and processing facilities in
the U.S. The data from three are included in this section.
These three facilities produce roughly one-half of the U.S.
production of this material.
Process Description
After the overburden is removed from the diatomite strata by
power-driven shovels, scrapers and bulldozers, the crude
diatomite is dug from the ground and loaded onto trucks.
Facilities 5504 and 5505 haul the crude diatomite directly
to the mills for processing. At facility 5500 the trucks
carry the crude diatomite to vertical storage shafts placed
in the formation at locations above a tunnel system. These
shafts have gates through which the crude diatomite is fed
to an electrical rail system for transportation to the
primary crushers.
At facility 5500, after primary crushing, blending, and
distribution, the material moves to different powder mill
units. For "natural" or uncalcined powders, crude diatomite
is crushed and then milled and dried simultaneously in a
current of heated air. The dried powder is sent through
separators to remove waste material and is further divided
into coarse and fine fractions. These powders are then
ready for packaging. For calcined powders, high temperature
rotary kilns are continuously employed. After classifying,
these powders are collected and packaged. To produce
flux-calcined powders, particles are sintered together into
microscopic clusters, then classified, collected and bagged.
At facilities 5504 and 5505, the ore is crushed, dried,
separated and classified, collected, and stored in bins for
shipping. Some of the diatomite is calcined at facility
5505 for a particular product. Diagrams for these processes
are given in Figure 28.
One facility surface-quarries an oil-impregnated diatomite,
which is crushed, screened, and calcined to drive off the
oil. The diatomite is then cooled, ground, and packaged.
In the future, the material will be heated and the oil
vaporized and recovered as a petroleum product.
Raw Waste Load
Wastes from these operations consist of the oversize waste
fraction from the classifiers and of fines collected in dust
control equipment. The amount is estimated to be 20 percent
of the mined material at facility 5500, 16-19 percent at
108
-------
*
VENT
WATER »
o
vc
MINE
-»a
CRUSH
LEGEND:
GENERAL PROCESS FLOW
ALTERNATE PROCESS
ROUTES
SCRUBBERS
I
BAG HOUSE
&
•BB
DRY
DUST
BINS
J
•^PRODUCT
AIR CLASSIFY
REAGENT
ROD MILL
| I
CALCINE
CLASSIFY
•PRODUCT
•PRODUCT
t
WATER
I
CYCLONE
TRAPS
I
MILL
T
1
LANE
WASTE TO LAND DISPOSAL
FIGURE 28.
D1ATOMITE MINING AND PROCESSING
-------
facility 5504 and 5-6 percent, solids as a slurry from
scrubber operations at facility 5505.
Facility 5500, oversize, 200
dust fines
Facility 5504, sand, rock, 175
heavy diatoms
Facility 5505, dust 45
fines (slurry)
Water Use
Water is used by facility 5500 in the principal process for
dust collection and for preparing the waste oversize
material for land disposal. In addition, a small amount of
bearing cooling water is used. Water is used in the process
at facility 5505 only in scrubbers used to cut down on dust
fines in processing, which is recycled from settling ponds
to the process. The only loss occurs through evaporation
with make-up water added to the system. Water is used in
the process at facility 5504 to slurry wastes to a closed
pond. This water evaporates and/or percolates into the
ground. As yet there is no recycle from -the settling pond.
l/kkg_or e_B roces s ed
Jgallgn/ton).
5500 5505™ 5504
Intake;
make-up water 2f800 880 3,800
(670) (210) (910)
Use:
dust collection 2,670 8,700 3,800
and waste disposal (640J (2,090) (910)
bearing cooling 125-160 (30-38) ---- ----
Consumption :
evaporation 2,800 B80 3,800
(pond and process) (670) (210) (910)
The much lower consumption of water at 5505 is due to the
use of recycling from the settling pond to the scrubbers.
110
-------
Waste Water Treatment
All waste water generated in diatomite preparation at
facility 5500 is evaporated on the land. Facilities 5504
and 5505 send waste water to settling ponds with water being
recycled to the process at facility 5505 and evaporated and
percolated to ground water at facility 5504.
Effluent and Disposal
The only waste water at facility 5500 is land-evaporated
on-site. There is no process water, cooling, or mine
pumpout discharge.
At facilities 5504 and 5505, the waste water from scrubbers
and waste fines slurrying is sent to settling ponds. At
facility 5505, the water is decanted and recycled to the
process, while facility 5504 currently impounds the water in
a closed pond and the water evaporates and/or percolates
into the ground. But in late 1974 a pump is being installed
to enable facility 5504 to decant and recycle the water from
the pond to the process. Thus, all of these diatomite
operations have no discharge of any waste water.
The oversize fraction and dust fines waste is land-dumped
on-site at facility 5500. The solids content of this
land-disposed waste is silica (diatomite) in the amount of
about 300,000 mg/1.
The waste slurries from facilities 5504 and 5505 consisting
of scrubber fines and dust are land-disposed with the solids
settling into ponds. The solids content of these slurries
is 24,000 mg/1 for facility 5505 and 146,000 mg/1 for
facility 5504.
Ill
-------
GRAPHITE
There is one producer of natural graphite in the United
States and data from this operation is presented in the
following sections.
Process Description
The graphite ore is produced from an open pit using
conventional mining methods of benching* breakage and
removal. The ore is properly sized for flotation by passing
through a 3-stage dry crushing and sizing system and then to
a wet grinding circuit consisting of a rod mill in closed
circuit with a classifier. Lime is added in the rod mill to
adjust pH for optimum flotation. The classifier discharge
is pumped to the flotation circuit where water additions are
made and various reagents added at different points in the
process flow. The graphite concentrate is floated,
thickened, filtered and dried. The underflow or waste
tailings from the cells are discharged as a slurry to a
settling pond. The process flow diagram for the facility is
shown in Figure 29.
Raw waste Loads
There are three sources of waste associated with the
facility operation. They are the tailings from the
flotation circuit, (36,000 kg/kkg product low pH seepage
water from the tailings pond (19,000 1/kkg product (4,500
gal/ton) under normal operating and weather conditions, and
an intermittent seepage from the mine. The flotation
reagents used in this process are alcohols and pine oils.
Water Use
The source of the intake water is almost totally from a
lake. The exceptions are that the drinking water is taken
from a well and a minimal volume for emergency or back-up
for the process comes from an impoundment of an intermittent
flowing creek. Some recycling of water takes place through
the reuse of thickener overflow, filtrate from the filter
operation and non-contact cooling water from compressors and
vacuum pumps.
112
-------
GRAPHITE ORE-
CRUSHING
AND
SCREENING
LIME WATE
1 1
MAKE-UP
WATER REAGENTS WATER
GRINDING
AND
CLASSIFICATION
( SEEPAGE
| MINE ! 2
| PITS |
I I
LIME
TREAT
FLOTATION
TAILINGS
SUMP
- TAILINGS
TAILINGS
POND
C2a
DRYER
RLTRATE
GRINDING
PRODOC
PRODUC
PLANT EFFLUENT
FIGURE 29.
GRAPHITE MINING AND PROCESSING
-------
total intake 159,000 (38,000)
process waste discharge 107,000 (26,000)
consumed (process, non-
contact cooling, sani- 52,000 (12,000)
ta-tion)
Waste water Treatment
The waste streams associated with the operation are
flotation tailings and seepage water. The tailings slurry
at about 20 percent solids and at a near neutral pH
(adjustment made for optimum flotation) is discharged to a
partially lined 8 hectare (20 acre) settling pond. The
solids settle rapidly and the overflow is discharged. The
seepage water from the tailings pond, mine and extraneous
surface waters are collected through the use of an extensive
network of ditches, dams and sumps. The collected waste
waters are pumped to a treatment facility where lime is
addad to neutralize the acidity and precipitate iron. The
neutralized water is pumped to the tailings pond where the
iron floe is deposited. The acid condition of the pond
seepage results from the extended contact of water with the
tailings which dissolve some part of the contained iron
pyrites.
Effluent
There is one effluent stream from this operation which is
the overflow from the tailings pond. It is discharged into
a stream that flows into the lake that serves as the intake
water source for the facility. The effluent composition
falls within the limits established by the Texas State Water
Quality Board for the following parameters: flow; pH; total
suspended solids; volatile solids; BOD; COD; manganese and
iron. Facility measurements compared to the state
limitations are:
114
-------
State Standards
Flow I/day
(gal/day)
total solids
TSS
Volatile
Solids
Mn
Total Fe
BOD
COD
PH
facility
average
mg/1
750
10
1
0.1
0,1
9
20
7.3-8.5
24 hr.
maximum
1,160,000
(300,000)
1600
20
10
0.5
2
15
20
6.8
monthly
average
1,820,000
(480,000)
1380
10
0.2
-
1
10
15
7.5
This facility has no problem meeting this requirement
because of a unique situation where the large volume of
tailings entering the pond assists the settling of suspended
solids more than that normally expected from a well designed
pond.
115
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JADE
The jade industry in the U.S. is very small. One facility
representing 55 percent of total U.S. jade production
provided the data for this section.
Process Description
The jade is mined in an open pit quarry, with rock being
obtained by pneumatic drilling and wedging of large angular
blocks. No explosives are used on the jade itself, only on
the surrounding host rock. The rock is then trucked to the
facility for processing. There the rock is sawed, sanded,
polished and packaged for shipping. Of the material
processed only a small amount (3 percent) is processed to
gems and 17 percent is processed to floor and table tiles,
grave markers, and artifacts. A general process diagram is
given in Figure 30.
Raw Waste Load
Approximately 50 percent of the rock taken each year from
the quarry is unusable or unavoidably wasted in processing,
amounting to 29.5 ton/yr). There is no mine pumpout
associated with this operation.
Water Use
Well water is used in the process for the wire saw, sanding,
and polishing operations. This water use amounts to
190 I/day (50 gpd) of which none is recycled.
Waste Water Treatment
Waste waters generated from the wire saw, sanding, and
polishing operations, are sent to settling tanks where the
tailings settle out and the water is discharged onto the
facility lawn where it evaporates and/or seeps into the
ground. There is no other water treatment employed. Solid
wastes in the form of tailings which collect in settling
tanks are eventually land-disposed as fill.
116
-------
QUARRY
WATER
AND
POLISHING
fATER
t
4
SiC OIL WATER SiC AGENTS
1 L- \ \ L.
r 1
WIRE
t SAW
i
1
|~" RECYCLE
DIAMOND
SAW
r i
| SETTLING
TANK
I
i
V
'ATER
TO
ROUND
TAIL
T
LAND
SETTLING
TANK
1 JL J~"
t t V
i V
^\RE
AG
PC
I
:N3S TAILINGS
0 TO
FILL LANDFILL
PRODUCT
RECYCLE POLISHING
AGENTS TO EXTENT
POSSIBLE
FIGURE 30.
JADE MINING AND PROCESSING
-------
NOVACULITE
Novaculite, a generic name for large geologic formations of
pure, microcrystalline silica, is mined only in Arkansas by
one facility. Open quarries are mined by drilling and
blasting, with a front-end loader loading trucks for
transport to covered storage at the facility. Since the
quarry is worked for only about 2 weeks per year, mining is
contracted out. Facility processing consists essentially of
crushing, drying, air classification and bagging. Normally
silica will not require drying but novaculite is hydrophilic
and will absorb water up to 9 parts per 100 ore. Part of
the air classifier product is diverted to a batch mixer,
where organics are reacted with the silica for specialty
products. A general process diagram is given in Figure 31.
Raw waste Load
Wastes generated in the mining of novaculite remain in the
quarry as reclaiming fill, and processing generates only
scrubber fines which are settled in a holding tank and
eventually used for land-fill. There is no data available
on the amount of this material. However, a new facility
dust scrubber will be installed with recycle of both water
and fines.
Water Use
No water is used in novaculite mining and the quarry is so
constructed that no water accumulates. Total water usage at
the facility for bearing cooling and the dust scrubber
totals approximately 18,900 I/day (5,000 gpd) of city water.
Of this total amount 7,300-1U,500 I/day (1,900-3,800 gpd) is
used for bearing cooling and an equivalent amount is used as
make-up water to the dust scrubber.
Waste Water Treatment
Water from the scrubber is sent to a settling tank and clear
water is recycled to the scrubber. cooling water is
discharged onto the facility lawn with no treatment.
Effluent and Disposal
Dust from the scrubber is currently land-disposed. However,
with the installment of a new dust scrubber both the water
and muds will be recycled to the process. Scrubber water is
recycled to the process after settling out of solids in a
tank. Cooling water is discharged onto the lawn at the
facility and it either seeps into the ground or evaporates.
118
-------
QUARRY
VENT
CRUSHER
DRYER
\-r^ A1R
***** CLASSIFY
PEBBLE
MILL
DRY
MIX
SPECIALTY
PRODUCTS
PRODUCT
RGURE rj.
NOVACULITE MINING AND PROCESSING
-------
-------
SECTION VI
SELECTION OF POLLUTANT PARAMETERS
INTRODUCTION
The waste water constituents of pollution significance for
this segment of the mineral mining and processing industry
are based upon those parameters which have been identified
in the untreated wastes from each subcategory of this study.
The waste water constituents are further divided into those
that have been selected as pollutants of significance with
the rationale for their selection, and those that are not
deemed significant with the rationale for their rejection.
The basis for selection of the significant pollutant para-
meters was:
(1) toxicity to humans, animals, fish and aquatic organisms;
(2) substances causing dissolved oxygen depletion in
streams;
(3) soluble constituents that result in undesirable tastes
and odors in water supplies;
(4) substances that result in eutrophication and stimulate
undesirable algae growth;
(5) substances that produce unsightly conditions in
receiving water; and
(6) substances that result in sludge deposits in streams.
SIGNIFICANCE AND RATIONALE FOR SELECTION OF POLLUTION
PARAMETERS
Biochemical Oxygen Demand (BOD)
Biochemical oxygen demand (BOD) is a measure of the oxygen
consuming capabilities of organic matter. The BOD does not
in itself cause direct harm to a water system, but it does
exert an indirect effect by depressing the oxygen content of
the water. Sewage and other organic effluents during their
processes of decomposition exert a BOD, which can have a
catastrophic effect on the ecosystem by depleting the oxygen
supply. Conditions are reached frequently where all of the
oxygen is used and the continuing decay process causes the
production of noxious gases such as hydrogen sulfide and
methane. Water with a high BOD indicates the presence of
decomposing organic matter and subsequent high bacterial
counts that degrade its quality and potential uses.
121
-------
Dissolved oxygen (DO) is a water quality constituent that,
in appropriate concentrations, is essential not only to keep
organisms living but also to sustain species reproduction,
vigor, and the development of populations. Organisms
undergo stress at reduced DO concentrations that make them
less competitive and able to sustain their species within
the aquatic environment. For example, reduced DO
concentrations have been shown to interfere with fish
population through delayed hatching of eggs, reduced size
and vigor of embryos, production of deformities in young,
interference with food digestion, acceleration of blood
clotting, decreased tolerance to certain toxicants, reduced
food efficiency and growth rate, and reduced maximum
sustained swimming speed. Fish food organisms are likewise
affected adversely in conditions with suppressed DO. Since
all aerobic aquatic organisms need a certain amount of
oxygen, the consequences of total lack of dissolved oxygen
due to a high BOD can kill all inhabitants of the affected
area.
If a high BOD is present, the quality of the water is
usually visually degraded by the presence of decomposing
materials and algae blooms due to the uptake of degraded
materials that form the foodstuffs of the algal populations.
BOD was not a major contribution to pollution in this
industry.
Fluorides
As the most reactive non-metal, fluorine is never found free
in nature but as a constituent of fluorite or fluorspar,
calcium fluoride, in sedimentary rocks and also of cryolite,
sodium aluminum fluoride, in igneous rocks. Owing to their
origin only in certain types of rocks and only in a few
regions, fluorides in high concentrations are not a common
constituent of natural surface waters, but they may occur in
detrimental concentrations in ground waters.
Fluorides are used as insecticides, for disinfecting brewery
apparatus, as a flux in the manufacture of steel, for
preserving wood and mucilages, for the manufacture of glass
and enamels, in chemical industries, for water treatment,
and for other uses.
Fluorides in sufficient quantity are toxic to humans, with
doses of 250 to 450 mg giving severe symptoms or causing
death.
122
-------
There are numerous articles describing the effects of
fluoride- bearing waters on dental enamel of children; these
studies lead to the generalization that water containing
less than 0.9 to 1.0 mg/1 of fluoride will seldom cause
mottled enamel in children, and for adults, concentrations
less than 3 or U mg/1 are not likely to cause endemic
cumulative fluorosis and skeletal effects. Abundant
literature is also available describing the advantages of
maintaining 0.8 to 1.5 mg/1 of fluoride ion in drinking
water to aid in the reduction of dental decay, especially
among children.
Chronic fluoride poisoning of livestock has been observed in
areas where water contained 10 to 15 mg/1 fluoride.
Concentrations of 30-50 mg/1 of fluoride in the total ration
of dairy cows is considered the upper safe limit. Fluoride
from waters apparently does not accumulate in soft tissue to
a significant degree and it is transferred to a very small
extent into the milk and to a somewhat greater degree into
eggs. Data for fresh water indicate that fluorides are
toxic to fish at concentrations higher than 1.5 mg/1.
Fluoride is found in one industry in this segment, feldspar
mining by the wet process.
Iron
Iron is considered to be a highly objectional constituent in
public water supplies, the permissible criterion has been
set at 0.3 mg/1. Iron is found in significant quantities in
graphite mining and other categories.
Manganese
Manganese in various dissolved forms may be present in
significant amounts in the waste water from the mining of
graphite. A permissible criterion of 0.05 mg/1 has been
proposed for public waters.
Oil and Grease
Oil and grease exhibit an oxygen demand. Oil emulsions may
adhere to the gills of fish or coat and destroy algae or
other plankton. Deposition of oil in the bottom sediments
can serve to exhibit normal benthic growths, thus
interrupting the aquatic food chain. Soluble and emulsified
material ingested by fish may taint the flavor of the fish
flesh. Water soluble components may exert toxic action on
fish. Floating oil may reduce the re-aeration of the water
surface and in conjunction with emulsified oil may interfere
with photosynthesis. Water insoluble components damage the
plumage and costs of water animals and fowls, oil and
grease in a water can result in the formation of
123
-------
objectionable surface slicks preventing the full aesthetic
enjoyment of the water. Oil spills can damage the surface
of boats and can destroy the aesthetic characteristics of
beaches and shorelines.
Acidity and Alkalinity
Acidity and alkalinity are reciprocal terms. Acidity is
produced by substances that yield hydrogen ions upon
hydrolysis and alkalinity is produced by substances that
yield hydroxyl ions. The terms "total acidity" and "total
alkalinity" are often used to express the buffering capacity
of a solution. Acidity in natural waters is caused by
carbon dioxide, mineral acids, weakly dissociated acids, and
the salts of strong acids and weak bases. Alkalinity is
caused by strong bases and the salts of strong alkalies and
weak acids.
The term pH is a logarithmic expression of the concentration
of hydrogen ions. At a pH of 7, the hydrogen and hydroxyl
ion concentrations are essentially equal and the water is
neutral. Lower pH values indicate acidity while higher
values indicate alkalinity. The relationship between pH and
acidity and alkalinity is not necessarily linear or direct.
Waters with a pH below 6.0 are corrosive to water works
structures, distribution lines, and household plumbing
fixtures and can thus add such constituents to drinking
water as iron, copper, zinc, cadmium and lead. The hydrogen
ion concentration can affect the "taste" of the water. At a
low pH water tastes "sour". The bactericidal effect of
chlorine is weakened as the pH increases, and it is
advantageous to keep the pH close to 7. This is very
significant for providing safe drinking water.
Extremes of pH or rapid pH changes can exert stress
conditions or kill aquatic life outright. Dead fish,
associated algal blooms, and foul stenches are aesthetic
liabilities of any waterway. Even moderate changes from
"acceptable11 criteria limits of pH are deleterious to some
species. The relative toxicity to aquatic life of many
materials is increased by changes in the water pH.
Metalocyanide complexes can increase a thousand-fold in
toxicity with a drop of 1.5 pH units. The availability of
many nutrient substances varies with the alkalinity and
acidity. Ammonia is more lethal with a higher pH.
The lacrimal fluid of the human eye has a pH of
approximately 7.0 and a deviation of 0.1 pH unit from the
norm may result in eye irritation for the swimmer.
Appreciable irritation will cause severe pain.
124
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Total Suspended Solids
Suspended solids include both organic and inorganic
materials. The inorganic components include sand, silt, and
clay. The organic fraction includes such materials as
grease, oil, tar, animal and vegetable fats, various fibers,
sawdust, hair and various materials from sewers. These
solids may settle out rapidly and bottom deposits are often
a mixture of both organic and inorganic solids. They
adversely affect fisheries by covering the bottom of the
stream or lake with a blanket of material that destroys the
fish-food bottom fauna or the spawning ground of fish.
Deposits containing organic materials may deplete bottom
oxygen supplies and produce hydrogen sulfide, carbon
dioxide, methane, and other noxious gases.
In raw water sources for domestic use, state and regional
agencies generally specify that suspended solids in streams
shall not be present in sufficient concentration to be
objectionable or to interfere with normal treatment
processes. Suspended solids in water may interfere with
many industrial processes, and cause foaming in boilers, or
encrustations on equipment exposed to water, especially as
the temperature rises. Suspended solids are undesirable in
water for textile industries; paper and pulp; beverages;
dairy products; laundries; dyeing; photography; cooling
systems, and power facilities. Suspended particles also
serve as a transport mechanism for pesticides and other
substances which are readily sorbed into or onto clay
particles.
Solids may be suspended in water for a time, and then settle
to the bed of the stream or lake. These settleable solids
discharged with man's wastes may be inert, slowly
biodegradable materials, or rapidly decomposable substances.
While in suspension, they increase the turbidity of the
water, reduce light penetration and impair the
photosynthetic activity of aquatic facilities.
Solids in suspension are aesthetically displeasing. When
they settle to form sludge deposits on the stream or lake
bed, they are often much more damaging to the life in water,
and they retain the capacity to displease the senses.
Solids, when transformed to sludge deposits, may do a
variety of damaging things, including blanketing the stream
or lake bed and thereby destroying the living spaces for
those benthic organisms that would otherwise occupy the
habitat. When of an organic and therefore decomposable
nature, solids use a portion or all of the dissolved oxygen
available in the area. Organic materials also serve as a
seemingly inexhaustible food source for sludgeworms and
associated organisms.
125
-------
Turbidity is principally a measure of the light absorbing
properties of suspended solids. It is frequently used as a
substitute method of quickly estimating the total suspended
solids when the concentration is relatively low. Total
suspended solids are the single most important pollutant
parameter found in this segment of the mineral mining and
processing industry.
Zinc
Occurring abundantly in rocks and ores, zinc is readily
refined into a stable pure metal and is used extensively for
qalvanizing, in alloys, for electrical purposes, in printing
plates, for dye- manufacture and for dyeing processes, and
for many other industrial purposes. Zinc salts are used in
paint pigments, cosmetics, Pharmaceuticals, dyes,
insecticides, and other products too numerous to list
herein. Many of these salts (e.g., zinc chloride and zinc
sulfate) are highly soluble in water; hence it is to be
expected that some zinc might be found in natural waters.
On the other hand, some zinc salts (zinc carbonate, zinc
oxide, zinc sulfide) are insoluble in water and consequently
it is to be expected that some zinc will precipitate and be
removed readily in most natural waters.
In zinc mining areas, zinc has been found in waters in
concentrations as high as 50 mg/1 and in effluents from
metal-plating works and small-arms ammunition facilities it
may occur in significant concentrations. In most surface
and ground waters, it is present only in trace amounts.
There is some evidence that zinc ions are adsorbed strongly
and permanently on silt, resulting in inactivation of the
zinc.
Concentrations of zinc in excess of 5 mg/1 in raw water used
for drinking water supplies cause an undesirable taste which
persists through conventional treatment. Zinc can have an
adverse effect on man and animals at high concentrations.
In soft water, concentrations of zinc ranging from 0.1 to
1.0 mg/1 have been reported to be lethal to fish. Zinc is
thought to exert its toxic action by forming insoluble
compounds with the mucous that covers the gills, by damage
to the gill epithelium, or possibly by acting as an internal
poison. The sensitivity of fish to zinc varies with
species, age and condition, as well as with the physical and
chemical characteristics of the water. Some acclimatization
to the presence of zinc is possible. It has also been
observed that the effects of zinc poisoning may not become
apparent immediately, so that fish removed from
zinc-contaminated to zinc-free water (after U-6 hours of
exposure to zinc) may die 48 hours later. The presence of
126
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copper in water may increase the toxicity of zinc to aquatic
organisms, but the presence of calcium or hardness may
decrease the relative toxicity.
Observed values for the distribution of zinc in ocean waters
vary widely. The major concern with zinc compounds in
marine waters is not one of acute toxicity, but rather of
the long-term sub-lethal effects of the metallic compounds
and complexes. From an acute toxicity point of view,
invertebrate marine animals seem to be the most sensitive
organisms tested. The growth of the sea urchin, for
example, has been retarded by as little as 30 mu/1 of zinc.
Zinc sulfate has also been found to be lethal to many
facilities, and it could impair agricultural uses. Zinc is
found in the effluent from one process in this industry,
high-grade kaolin.
SIGNIFICANCE AND RATIONAL FOR REJECTION
PARAMETERS
OF
POLLUTION
A number of pollution parameters besides those selected were
considered, but were rejected for one or several of the
following reasons:
1) insufficient data on facility effluents;
2) not usually present in quantities sufficient to cause
water quality degradation;
3) treatment does not "practicably" reduce the parameter;
and
4) simultaneous reduction is achieved with another
parameter which is limited.
Toxic Materials
Although arsenic, antimony, barium, boron, cadmium,
chromium, copper, cyanide ion, mercury, nickel, lead,
selenium, and tin are harmful pollutants, they were not
found to be present in quantities sufficient to cause water
quality degradation.
Dissolved Solids
The cations A1+3, Ca+2, Mg+2, K+ and Na+, the anion Cl~ and
the radical groups CO3~2, NO3-, NO2-, phosphates, and
silicates are commonly found in all natural water bodies.
Process water, mine water and storm runoff will accumulate
quantities of the above constituents both in the form of
suspended and dissolved solids. Limiting suspended solids
and dissolved solids, where they pose a problem, is a more
practicable approach to limiting these specific ions.
127
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Temperature
Temperature is one of the most important and influential
water quality characteristics. Temperature determines those
species that may be present; it activates the hatching of
young, regulates their activity, and stimulates or
suppresses their growth and development; it attracts, and
may kill when the water becomes too hot or becomes chilled
too suddenly. colder water generally suppresses
development. Warmer water generally accelerates activity
and may be a primary cause of aquatic facility nuisances
when other environmental factors are suitable.
Temperature is a prime regulator of natural processes within
the water environment. It governs physiological functions
in organisms and, acting directly or indirectly in
combination with other water quality constituents, it
affects aquatic life with each change. These effects
include chemical reaction rates, enzymatic functions,
molecular movements, and molecular exchanges between
membranes within and between the physiological systems and
the organs of an animal.
Chemical reaction rates vary with temperature and generally
increase as the temperature is increased. The solubility of
gases in water varies with temperature. Dissolved oxygen is
decreased by the decay or decomposition of dissolved organic
substances and the decay rate increases as the temperature
of the water increases reaching a maximum at about 30°C
(86°F). The temperature of stream water, even during
summer, is below the optimum for pollution-associated
bacteria. Increasing the water temperature increases the
bacterial multiplication rate when the environment is
favorable and the food supply is abundant.
Reproduction cycles may be changed significantly by
increased temperature because this function takes place
under restricted temperature ranges. Spawning may not occur
at all because temperatures are too high. Thus, a fish
population may exist in a heated area only by continued
immigration. Disregarding the decreased reproductive
potential, water temperatures need not reach lethal levels
to decimate a species. Temperatures that favor competitors,
predators, parasites, and disease can destroy a species at
levels far below those that are lethal.
Fish food organisms are altered severely when temperatures
approach or exceed 90°F. Predominant algal species change,
primary production is decreased, and bottom associated
organisms may be depleted or altered drastically in numbers
and distribution. Increased water temperatures may cause
128
-------
aquatic facility nuisances when other environmental factors
are favorable.
Synergistic actions of pollutants are more severe at higher
water temperatures. Given amounts of domestic sewage,
refinery wastes, oils, tars, insecticides, detergents, and
fertilizers more rapidly deplete oxygen in water at higher
temperatures, and the respective » toxicities are likewise
increased.
When water temperatures increase, the predominant algal
species may change from diatoms to green algae, and finally
at high temperatures to blue-green algae, because of species
temperature preferentials. Blue-green algae can cause
serious odor problems. The number and distribution of
benthic organisms decreases as water temperatures increase
above 90°F, which is close to the tolerance limit for the
population. This could seriously affect certain fish that
depend on benthic organisms as a food source.
The cost of fish being attracted to heated water in winter
months may be considerable, due to fish mortalities that may
result when the fish return to the cooler water.
Rising temperatures stimulate the decomposition of sludge,
formation of sludge gas, multiplication of saprophytic
bacteria and fungi (particularly in the presence of organic
wastes), and the consumption of oxygen by putrefactive
processes, thus affecting the esthetic value of a water
course.
In general, marine water temperatures do not change as
rapidly or range as widely as those of freshwaters. Marine
and estuarine fishes, therefore, are less tolerant of
temperature variation. Although this limited tolerance is
greater in estuarine than in open water marine species,
temperature changes are more important to those fishes in
estuaries and bays than to those in open marine areas,
because of the nursery and replenishment functions of the
estuary that can be adversely affected by extreme
temperature changes.
Excess thermal load, even in non-contact cooling water, has
not been and is not expected to be a significant problem in
this segment of the mineral mining and processing industry.
129
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-------
SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
INTRODUCTION
Water-borne wastes from the mining of clay, ceramic,
refractory and miscellaneous minerals consist primarily of
suspended solids. These are usually composed of chemically
inert and very insoluble sand, clay or rock particles.
Treatment technology is well developed for removing such
particles from waste water and is readily applicable when-
ever space requirements or economics do not preclude uti-
lization.
In a few instances dissolved substances such as fluorides,
metal salts, acids, alkalies, chemical additives from ore
processing and organic materials may also be involved.
Where they are present, dissolved material concentrations
are usually low. Treatment technology for the dissolved
solids is also well-known, but may often be limited by the
large volumes of waste water involved and the cost of such
large scale operations.
The control and treatment of the usually simple water-borne
wastes found in the mineral mining and processing industry
are complicated by several factors:
(1) the large volumes of waste water involved for many of
the mining operations,
(2) variable waste water amount and composition from day to
day, as influenced by rainfall and other surface and
underground water contributions,
(3) differences in waste water compositions arising from ore
or raw material variability,
(4) geographical location: e.g., waste water can be handled
differently in dry isolated locations than in
industrialized wet climates.
Each of these points are discussed in the following
sections.
131
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PROBLEM POLLUTANTS
Three significant waste water problem areas have been found
in these industries:
(1) High suspended solids levels in discharged waste waters
caused in some cases by formation of colloidal clay sus-
pensions which are difficult to settle. This problem is
encountered in several segments of the industry;
(2) In at least one subcategory of this industry problems
are encountered with water-borne fluoride wastes;
(3) In the bleaching of some clay products, zinc
hydrosulfite is sometimes employed. The use of this
material invariably leads to a waste water discharge
containing zinc salts.
Below are given brief discussions of each of these problem
areas.
The principal pollutant encountered in this segment of the
minerals mining industry has been found to be suspended
solids which arise from two sources:
(1) underground or surface mine pumpouts;
(2) processing washwaters and scrubber waters.
Mine water pumpout was found to be intermittent in nature
and to be characterized by TSS loadings of from a few to
several thousand mg/1 of suspended solids prior to settling.
Installation of settling areas for such waters generally has
the effect reducing TSS loadings to less than 20 mg/1 for
most materials. It should be pointed out that mine pumpout
waters from montmorillonite clay mining facilities appear to
be an exception to the above statement. This type of clay
forms colloidal suspensions in waste water that are very
difficult to settle. These colloidal suspensions can be
flocculated by addition of soluble calcium salts at
concentrations of about 100 milliequivalents of calcium salt
per 100 grams of suspended montmorillonite (1,2). For other
clays which settle more readily, flocculation occurs
generally at lower concentrations of added calcium salt.
This approach apparently has yet to be tried in the
industry. Other approaches mentioned in the literature,
such as treatment of clays with alkyl ammonium salts (3,4)
are not likely to be applicable to this situation because
their use would cause worse environmental problems than
those already present.
132
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Process water discharge is encountered in several of the
product subcategories. For readily settleable materials,
settling lagoons were found to be effective in reducing
suspended solids loadings to less than 20 mg/1 in most
instances. For a few of the clay materials, such as
montmorillonite and fire clays, pond effluent concentrations
after simple settling tend to be at least an order of
magnitude higher in TSS. For one specific case with a
montmorillonite facility, scrubber waste waters were found
with a TSS loading of 25,000 mg/1 before settling. After
settling with a retention time of less than five days in a
small lagoon, TSS loadings of about 2,000 mg/1 were still
present. Table 5 shows the settling characteristics of some
of the materials treated in this volume. Application of
available flocculation and clarification technology is
needed in this area.
The processing of feldspar ores involves a flotation step in
which hydrofluoric acid is added. This gives rise to an
acidic fluoride bearing waste water stream which, prior to
treatment, can contain 50 mg/1 fluoride ion. At present,
treatment of such waste waters has been only partially
practiced. current fluoride effluent concentrations at
feldspar producing facilities range from 8 to about 40 mg/1.
This is another area where improved treatment technology is
needed.
In the bleaching of kaolin, solutions of zinc hydrosulfite
are generally employed. This gives rise to waste waters
containing 25 mg/1 zinc ion prior to treatment. Technology
already in use in the pigments and inorganic chemicals
industries is available to reduce effluent levels to less
than 25 mg/1. This will be discussed later in this section.
CONTROL PRACTICES
Control practices such as selection of raw materials, good
housekeeping, minimizing leaks and spills, in-process
changes, and segregation of process waste water streams are
not as important in the minerals mining industry as they are
in more process-oriented manufacturing operations. Raw
materials are fixed by the composition of the ore available;
good housekeeping and small leaks and spills have little
influence on the waste loads; and it is rare that any
non-contact water, such as cooling water, is involved in
minerals and mining processes.
There are a number of areas, however, where control is very
important. These include:
133
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Table 5
Settling Character rstfes of Some Suspended Materials
u,
Product
FJre Cloy
Montmorf I lonf re
Kaolin
Ball Cloy
Feldspar
Talc
Stream
mine
seepage,
runoff, &
cooling
scrubber
pit
pumpout
plant
raw
effluent
scrubber
scrubbers
plant
raw
effluent
mine
pumpout
Plant
3087
3072
3073
3024
5685
5689
3026
2041,
2042,
2043,
2044
Input to Pond
(mg/Hter)
unknown
25,000
unknown
10,300
includes sand
unknown
unknown
3,800
200
Retention Time,
Condition
0.25 hour
soda ash added
4.1 days,
lime added
variable
unknown,
lime added
1-2 months.
simple settling
1 month,
flocculant,
3 ponds
unknown,
alum added,
2 ponds
unknown
Outflow
(mg/liter)
45
2,000
215
6
400
40
21
<20
-------
(1) waste water containment:
(2) separation and control of mine water, process water,
and rain water
(3) monitoring of waste streams.
Containment
The majority of waste water treatment and control facilities
in the minerals and mining industry use one or more settling
ponds. often the word "pond" is an euphemism for swamp,
gully, or other low spot which will collect water. In times
of heavy rainfall these "ponds" often and the settled solids
may be swept out. In many other cases, the identity of the
pond may be maintained during rainfall but its function as a
settling pond is significantly impaired by the large amount
of water flowing through it. In addition to rainfall and
flooding conditions, waste containment in ponds can be
troubled with seepage through the ground around and beneath
the pond, escape through pot holes, faults and fissures
below the water surface and physical failure of pond dams
and dikes.
In most instances satisfactory pond performance can be
achieved by proper design. In instances where preliminary
laboratory tests indicate that insufficient land is
available to achieve satisfactory suspended solids removal,
alternative treatment methods can be utilized: thickeners,
clarifiers, tube and lamella separators, filters,
hydrocyclones, and centrifuges.
Separation and control of Waste water
In these industries waste water may be separated into three
different categories:
(1) MiQ§ drainage water. For many mines this is the only
water ""effluent?Usually it is low in suspended solids,
but may contain dissolved minerals.
(2) Process water* This is water involved in transporting,
classllying7~wasning, beneficimting, and separating ores
and other mined materials. when present in minerals
mining operations this water usually contains heavy
loads of suspended solids and possibly some dissolved
materials.
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(3) Rain water runoff. Since minerals mining operations
often involve large surface areas, the rain water that
falls on the mine or mine property surface constitutes a
major portion of the overall waste water load leaving
the property. This runoff entrains minerals, silt,
sand, clay, organic matter and other suspended solids.
The relative amounts and compositions of the above waste
water streams differ from one mining category to another and
the separation, control and treatment techniques differ for
each.
Process water and mine drainage are normally controlled and
contained by pumping or gravity flow through pipes,
channels, ditches and ponds. Rain water runoff, on the
other hand, is often uncontrolled and may contaminate
process and mine drainage water. Rain water runoff also
increases suspended solid material in rivers, streams,
creeks or other surface water used for process water supply.
Control technology, as discussed in this report, includes
techniques and practices employed before, during, and after
the actual mining or processing operation to reduce or
eliminate adverse environmental effects resulting from the
discharge of mine or process facility waste water,
Effective pollution-control planning can reduce pollutant
contributions from active mining and processing sites and
can also minimize post-operational pollution potential.
Because pollution potential may not cease with closure of a
mine or process facility, control measures also refer to
methods practiced after an operation has terminated
production of ore or concentrated product. The presence of
pits, storage areas for spoil (non-ore material, or waste) ,
tailing ponds, disturbed areas, and other results or effects
of mining or processing operations necessitates integrated
plans for reclamation, stabilization, and control to return
the affected areas to a condition at least fully capable of
supporting the uses which it was capable of supporting prior
to any mining and to achieve a stability not posing any
threat of water diminution, or pollution and to minimize
potential hazards associated with closed operations.
Mining Techniques
Mining techniques can effectively reduce amounts of
pollutants coming from a mine area by containment within the
mine area or by reducing their formation. These techniques
can be combined with careful reclamation planning and
implementation to provide maximum at-source pollution
control.
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Several techniques have been implemented to reduce
environmental degradation during strip-mining operations.
Utilization of the box-cut technique in moderate- and
shallow-slope contour mining has increased recently because
more stringent environmental controls are being implemented.
A box cut is simply a contour strip mine in which a low-wall
barrier is maintained. Spoil may be piled on the low wall
side. This technique significantly reduces the amount of
water discharged from a pit area, since that water is
prevented from seeping through spoil banks. The problems of
preventing slides, spoil erosion, and resulting stream
sedimentation are still present, however.
Block-cut mining was developed to facilitate regrading,
minimize overburden handling, and contain spoil within
mining areas. In block-cut mining, contour stripping is
typically accomplished by throwing spoil from the bench onto
downslope areas. This downslope material can slump or
rapidly erode and must be moved upslope to the mine site if
contour regrading is desired. The land area affected by
contour strip mining is substantially larger than the area
from which the ores are extracted. When using block-cut
mining, only material from the first cut is deposited in
adjacent low areas. Remaining spoil is then placed in mined
portions of the bench. Spoil handling is restricted to the
actual pit area for all areas but the first cut, which
significantly reduces the area disturbed.
Pollution-control technology in underground mining is
largely restricted to at-source methods of reducing water
influx into mine workings. Infiltration from strata
surrounding the workings is the primary source of water, and
this water reacts with air and sulfide minerals within the
mines to create acid pH conditions and, thus, to increase
the potential for solubilization of metals. Underground
mines are, therefore, faced with problems of water handling
and mine-drainage treatment. Open-pit mines, on the other
hand, receive both direct rainfall and runoff contributions,
as well as infiltrated water from intercepted strata.
Infiltration in underground mines generally results from
rainfall recharge of a ground-water reservoir. Rock
fracture zones, joints, and faults have a strong influence
on ground-water flow patterns since they can collect and
convey large volumes of water. These zones and faults can
intersect any portion of an underground mine and permit easy
access of ground water. In some mines, infiltration can
result in huge volumes of water that must be handled and
treated. Pumping can be a major part of the mining
operation in terms of equipment and expense—particularly,
in mines which do not discharge by gravity.
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Water-infiltration control techniques, designed to reduce
the amount of water entering the workings, are extremely
important in underground mines located in or adjacent to
water-bearing strata. These techniques are often employed
in such mines to decrease the volume of water requiring
handling and treatment, to make the mine workable, and to
control energy costs associated with dewatering. The
techniques include pressure grouting of fissures which are
entry points for water into the mine. New polymer-based
grouting materials have been developed which should improve
the effectiveness of such grouting procedures. In severe
cases, pilot holes can be drilled ahead of actual mining
areas to determine if excessive water is likely to r be
encountered. When water is encountered, a small pilot hole
can be easily filled by pressure grouting, and mining
activity may be directed toward non-water-contributing areas
in the formation. The feasibility of such control is a
function of the structure of the ore body, the type of
surrounding rock, and the characteristics of ground water in
the area.
Decreased water volume, however, does not necessarily mean
that waste water pollutant loading will also decrease. In
underground mines, oxygen, in the presence of humidity,
interacts with minerals on the mine walls and floor to
permit pollutant formation e.g., acid mine water, while
water flowing through the mine transports pollutants to the
outside. If the volume of this water is decreased but the
volume of pollutants remains unchanged, the resultant
smaller discharge will contain increased pollutant
concentrations, but approximately the same pollutant load.
Rapid pumpout of the mine can, however, reduce the contact
time and significantly reduce the formation of pollutants.
Reduction of mine discharge volume can reduce water handling
costs. In cases of acid mine drainage, for example, the
same amounts of neutralizing agents will be required because
pollutant loads will remain unchanged. The volume of mine
water to be treated, however, will be reduced significantly,
together with the size of the necessary treatment and
settling facilities. This cost reduction, along with cost
savings which can be attributed to decreased pumping volumes
(hence, smaller pumps, lower energy requirements, and
smaller treatment facilities), makes use of water
infiltration-control techniques highly desirable.
Water entering underground mines may pass vertically through
the mine roof from rock formation above. These rock units
may have well-developed joint systems (fractures along which
no movement occurs), which tend to facilitate vertical flow.
Roof collapses can also cause widespread fracturing in over-
lying rocks, as well as joint separation far above the mine
138
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roof. Opened joints may channel flow from overlying
aquifers (water-bearing rocks), a flooded mine above, or
even from the surface.
Fracturing of overlying strata is reduced by employing any
or all of several methods: (1) Increasing pillar size; (2)
Increasing support of the roof; (3) Limiting the number of
mine entries and reducing mine entry widths; (4) Backfilling
of the mined areas with waste material.
Surface mines are often responsible for collecting and
conveying large quantities of surface water to adjacent or
underlying underground mines. Ungraded surface mines often
collect water in open pits when no surface discharge point
is available. That water may subsequently enter the ground-
water system and then percolate into an underground mine.
The influx of water to underground mines from either active
or abandoned surface mines can be significantly reduced
through implementation of a well-designed reclamation plan.
The only actual underground mining technique developed
specifically for pollution control is preplanned flooding.
This technique is primarily one of mine design, in which a
mine is planned from its inception for post-operation
flooding or zero discharge. In drift mines and shallow
slope or shaft mines, this is generally achieved by working
the mine with the dip of the rock (inclination of the rock
to the horizontal) and pumping out the water which collects
in the shafts. Upon completion of mining activities, the
mine is allowed to flood naturally, eliminating the
possibility of acid formation caused by the contact between
sulfide minerals and oxygen. Discharges, if any, from a
flooded mine should contain a much lower pollutant
concentration. A flooded mine may also be sealed.
Surface-Water Control
Pollution-control technology related to mining areas, ore-
beneficiation facilites, and waste-disposal sites is
generally designed for prevention of pollution of surface
waters (i.e., streams, impoundments, and surface runoff).
Prior planning for waste disposal is a prime control method.
Disposal sites should be isolated from surface flows and
impoundments to prevent or minimize pollution potential. In
addition, several techniques are practiced to prevent water
pollution:
(1) Construction of a clay or other type of liner
beneath the planned waste disposal area to prevent
infiltration of surface water (precipitation) or
water contained in the waste into the ground-water
system.
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(2) Compaction of waste material to reduce
infiltration.
(3) Maintenance of uniformly sized refuse to enhance
good compaction (which may require additional
crushing).
(U) Construction of a clay liner over the material to
minimize infiltration. This is usually succeeded
by placement of topsoil and seeding to establish a
vegetative cover for erosion protection and runoff
control.
(5) Excavation of diversion ditches surrounding the
refuse disposal site to exclude surface runoff from
the area. These ditches can also be used to
collect seepage from refuse piles, with subsequent
treatment, if necessary.
Surface runoff in the immediate area of beneficiation
facilities presents another potential pollution problem.
Runoff from haul roads, areas near conveyors, and ore
storage piles is a potential source of pollutant loading to
nearby surface waters. Several current industry practices
to control this pollution are:
(1) Construction of ditches surrounding storage areas
to divert surface runoff and collect seepage that
does occur.
(2) Establishment of a vegetative cover of grasses in
areas of potential sheet wash and erosion to
stabilize the material, to control erosion and
sedimentation, and to improve the aesthetic aspects
of the area.
(3) Installation of hard surfaces on haul roads,
beneath conveyors, etc., with proper slopes to
direct drainage to a sump. Collected waters may be
pumped to an existing treatment facility for
treatment.
Another potential problem associated with construction of
tailing-pond treatment systems is the use of existing
valleys and natural drainage areas for impoundment of mine
water or process facility process waste water. The capacity
of these impoundment systems freguently is not large enough
to prevent high discharge flow rates—particularly, during
the late winter and early spring months. The use of
ditches, flumes, pipes, trench drains, and dikes will assist
in preventing runoff caused by snowmelt, rainfall, or
streams from entering impoundments. Very often, this runoff
140
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flow is the only factor preventing attainment of zero
discharge. Diversion of natural runoff from impoundment
treatment systems, or construction of these facilities in
locations which do not obstruct natural drainage, is
therefore, desirable.
Ditches may be constructed upslope from the impoundment to
prevent water from entering it. These ditches also convey
water away and reduce the total volume of water which must
be treated. This may result in decreased treatment costs,
which could offset the costs of diversion.
Sea££3a£i9.Q Q£ Combination of Mine and Process Facility.
Wastewaters
A widely adopted control practice in the ore mining and
dressing industry is the use of mine water as a source of
process water. In many areas, this is a highly desirable
practice, because it serves as a water-conservation measure.
Waste constituents may thus be concentrated into one waste
stream for treatment. In other cases, however, this
practice results in the necessity for discharge from a
process facility-water impoundment system because, even with
recycle of part of the process water, a net positive water
balance results.
At several sites visited as part of this study, degradation
of the mine water quality is caused by combining the waste-
water streams for treatment at. one location. A negative
effect results because water with low pollutant loading
serves to dilute water of higher pollutant loading. This
often results in decreased water-treatment efficiency
because concentrated waste streams can often be treated more
effectively than dilute waste streams. The mine water in
these cases may be treated by relatively simple methods;
while the volume of waste water treated in the process
facility impoundment system will be reduced, this water will
be treated with increased efficiency.
There are also locations where the use of mine water as
process water has resulted in an improvement in the ultimate
effluent. Choice of the options to segregate or combine
waste water treatment for mines and process facilities must
be made on an individual basis, taking into account the
character of the waste water to be treated (at both the mine
and the process facility), the water balance in the
mine/process facility system, local climate, and topography.
The ability of a particular operation to meet zero or
reduced effluent levels may be dependent upon this decision
at each location.
Reqrading
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Surface mining may often require removal of large amounts of
overburden to expose the ores to be exploited. Regrading
involves mass movement of material following ore extraction
to achieve a more desirable land configuration. Reasons for
regrading strip mined land are:
(1) aesthetic improvement of land surface
(2) returning usefulness to land
(3) providing a suitable base for revegetation
(4) burying pollution-forming materials, e.g. heavy metals
(5) reducing erosion and subsequent sedimentation
(6) eliminating landsliding
(7) encouraging natural drainage
(8) eliminating ponding
(9) eliminating hazards such as high cliffs and deep pits
(10) controlling water pollution
Contour regrading is currently the required reclamation
technique for many of the nationsfs active contour and area.
surface mines. This technique involves regrading a mine to
approximate original land contour. It is generally one of
the most favored and aesthetically pleasing regrading tech-
niques because the land is returned to its approximate pre-
mined state. This technique is also favored because nearly
all spoil is placed back in the pit, eliminating
oversteepened downslope spoil banks and reducing the size of
erodable reclaimed area. Contour regrading facilitates deep
burial of pollution-forming materials and minimizes contact
time between regraded spoil and surface runoff, thereby
reducing erosion and pollution formation.
However, there are also several disadvantages to contour
regrading that must be considered. In area and contour
stripping, there may be other forms of reclamation that
provide land configurations and slopes better suited to the
intended uses of the land. This can be particularly true
with steepslope contour strips, where large, high walls and
steep final spoil slopes limit application of contour
regrading. Mining is, therefore, frequently prohibited in
such areas, although there may be other regrading techniques
that could be effectively utilized. In addition, where
extremely thick ore bodies are mined beneath shallow
overburden, there may not be sufficient spoil material
remaining to return the land to the original contour.
There are several other reclamation techniques of varying
effectiveness which have been utilized in both active and
abandoned mines. These techniques include terrace, swalef
swallow-tail, and Georgia V-ditch, several of which are
quite similar in nature. In employing these techniques, the
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upper high-wall por-tion is frequently left, exposed or
backfilled at a steep angle, with the spoil outslope
remaining somewhat steeper than the original contour. In
all cases, a terrace of some form remains where the original
bench was located, and there are provisions for rapidly
channeling runoff from the spoil area. Such terraces may
permit more effective utilization of surface-mined land in
many cases.
Disposal of excess spoil material is frequently a problem
where contour backfilling is not practiced. However, the
same problem can also occur, although less commonly, where
contour regrading is in use. Some types of overburden rock-
particularly, tightly packed sandstones—substantially
expand in volume when they are blasted and moved. As a
result, there may be a large volume of spoil material that
cannot be returned to the pit area, even when contour
backfilling is employed. To solve this problem, head-of-
hollow fill has been used for overburden storage. The extra
overburden is placed in narrow, steep-sided hollows in
compacted layers 1.2 to 2.4 meters (4 to 8 feet) thick and
graded to control surface drainage.
In this regrading and spoil storage technique, natural
ground is cleared of woody vegetation, and rock drains are
constructed where natural drains exist, except in areas
where inundation has occurred. This permits ground water
and natural percolation to leave fill areas without
saturating the fill, thereby reducing potential landslide
and erosion problems. Normally, the face of the fill is
terrace graded to minimize erosion of the steep outslope
area.
This technique of fill or spoil material deposition has been
limited to relatively narrow, steep-sided ravines that can
be adequately filled and graded. Design considerations
include the total number of acres in the watershed above a
proposed head-of-hollow fill, as well as the drainage, slope
stability, and prospective land use. Revegetation usually
proceeds as soon as erosion and sil«tation protection have
been completed. This technique is avoided in areas wnere
under-drainage materials contain high concentrations of
pollutants, since the resultant drainage would require
treatment to meet pollution-control requirements.
lEQsign Control
Although regrading is the most essential part of surface-
mine reclamation, it cannot be considered a total
reclamation technique. There are many other facets of
surface-mine reclamation that are equally important in
achieving successful reclamation. The effectivenesses of
143
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regrading and other control techniques are interdependent.
Failure of any phase could severly reduce the effectiveness
of an entire reclamation project.
The most important auxiliary reclamation procedures employed
at regraded surface mines or refuse areas are water
diversion and erosion and runoff control. Water diversion
involves collection of water before it enters a mine area
and conveyance of that water around the mine site, as
discussed previously. This procedure decreases erosion and
pollution formation. Ditches are usually excavated upslope
from a mine site to collect and convey water. Flumes and
pipes are used to carry water down steep slopes or across
regraded areas. Riprap and dumped rock are sometimes used
to reduce water velocity in the conveyance system.
Diversion and conveyance systems are designed to accommodate
predicted water volumes and velocities. If the capacity of
a ditch is exceeded, water erodes the sides and renders the
ditch ineffective.
Water diversion is also employed as an actual part of the
mining procedure. Drainways at the bases of high walls
intercept and divert discharging ground water prior to its
contact with pollution-forming materials. In some
instances, ground water above the mine site is pumped out
before it enters the mine area, where it would become
polluted and require treatment. Soil erosion is
significantly reduced on regraded areas by controlling the
course of surface-water runoff, using interception channels
constructed on the regraded surface.
Water that reaches a mine site, such as direct rainfall, can
cause serious erosion, sedimentation, and pollution
problems. Runoff-control techniques are available to
effectively deal with this water, but these techniques may
conflict with pollution-control measures. Control of
chemical pollutants forming at a mine frequently involves
reduction of water infiltration, while runoff controls to
prevent erosion usually increase infiltration, which can
subsequently increase pollutant formation.
There are a large number of techniques in use for
controlling runoff, with highly variable costs and degrees
of effectiveness. Mulching is sometimes used as a. temporary
measure which protects the runoff surface from raindrop
impacts and reduces tha velocity of surface runoff.
Velocity reduction is a critical facet of runoff control.
This is accomplished through slope reduction by terracing or
grading; revegetation; or use of flow impediments such as
dikes, contour plowing, and dumped rock. Surface
144
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stabilizers have been utilized on the surface to temporarily
reduce erodability of the material itself, but expense has
restricted use of such materials in the past.
Establishment of good vegetative cover on a mine area is
probably the most effective method of controlling runoff and
erosion. A critical factor in mine revegetation is the
quality of the soil or spoil material on the surface of a
regraded mine. There are several methods by which the
nature of this material has been controlled. Topsoil
segregation during stripping is mandatory in many states.
This permits topsoil to be replaced on a regraded surface
prior to revegetation. However, in many forested, steep-
sloped areas, there is little or no topsoil on the
undisturbed land surface. In such areas, overburden
material is segregated in a manner that will allow the most
toxic materials to be placed at the base of the regraded
mine, and the best spoil material is placed on the mine
surface.
Vegetative cover provides effective erosion control; contri-
butes significantly to chemical pollution control; results
in aesthetic improvement; and can return land to
agricultural, recreational, or silvicultural usefulness. A
dense ground cover stabilizes the surface (with its root
system), reduces velocity of surface runoff, helps build
humus on the surface, and can virtually eliminate erosion.
A soil profile begins to form, followed by a complete soil
ecosystem. This soil profile acts as an oxygen barrier,
reducing the amount of oxygen reaching underlying materials.
This, in turn, reduces oxidation, which is a major
contributing factor to pollutant formation.
The soil profile also tends to act as a sponge that retains
water near the surface, as opposed to the original loose
spoil (which allowed rapid infiltration). This water
evaporates from the mine surface, cooling it and enhancing
vegetative growth. Evaporated water also bypasses toxic
materials underlying the soil, decreasing pollution
production. The vegetation itself also utilizes large
quantities of water in its life processes and transpires it
back to the atmosphere, again reducing the amount of water
reaching underlying materials.
Establishment of an adequate vegetative cover at a mine site
is dependent on a number of'related factors. The regraded
surface of many spoils cannot support a good vegetative
cover without supplemental treatment. The surface texture
is often too irregular, requiring the use of raking to
145
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remove as much rock as possible and -to decrease the average
grain size of -the remaining material. Materials toxic to
plant life, usually buried during regrading, generally do
not appear on or near the final graded surface. If the
surface is compacted, it is usually loosened by discing,
plowing, or roto-tilling prior to seeding in order to
enhance plant growth.
Soil supplements are often required to establish a good
vegetativte cover on surface-mined lands and refuse piles,
which are generally deficient in nutrients. Mine spoils are
often acidic, and lime must be added to adjust the pH to the
tolerance range of the species to be planted. It may be
necessary to apply additional neutralizing material to
revegetated areas for some time to offset continued
pollutant generation.
several potentially effective soil supplements are currently
undergoing research and experimentation. Flyash is a waste
product of coal-fired boilers and resembles soil with
respect to certain physical and chemical properties. Flyash
is often alkaline, contains some plant nutrients, and
possesses moisture retaining and soil-conditioning
capabilities. Its main function is that of an alkalinity
source and a soil conditioner, although it must usually be
augmented with lime and fertilizers. However, flyash can
vary drastically in quality—particularly, with respect to
pH—and may contain leachable materials capable of producing
water pollution. Future research, demonstration, and
monitoring of flyash supplements will probably develop the
potential use of such materials.
Limestone screenings are also an effective long-term neutra-
lizing agent for acidic spoils. Such spoils generally
continue to produce acidity as oxidation continues, use of
lime for direct planting upon these surfaces is effective,
but it provides only short-term alkalinity. The lime is
usually consumed after several years, and the spoil may
return to its acidic condition. Limestone screenings are of
larger particle size and should continue to produce
alkalinity on a decreasing scale for many years, after which
a vegetative cover should be well-established. Use of large
quantities of limestone should also add alkalinity to
receiving streams. These screenings are often cheaper than
lime, providing larger quantities of alkalinity for the same
cost. Such applications of limestone are currently being
demonstrated in several areas.
Use of digested sewage sludge as a soil supplement also has
good possibilities for replacing fertilizer and
simultaneously alleviating the problem of sludge disposal.
Sewage sludge is currently being utilized for revegetation
146
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in strip-mined areas of Ohio. Besides supplying various
nutrients, sewage sludge can reduce acidity cr alkalinity
and effectively increase soil absorption and moisture-
retention capabilities. Digested sewage sludge can be
.applied in liquid or dry form and must be incorporated into
the spoil surface. Liquid sludge applications require large
holding ponds or tank trucks, from which sludge is pumped
and sprayed over the ground, allowed to dry, and disced in-i-o
the underlying material. Dry sludge application requires
dryspreading machinery and must be followed by discing.
Limestone, digested sewage sludge, and flyash are all
limited by their availabilities and chemical compositions.
Unlike commercial fertilizers, the chemical compositions 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 application. Flyash, digested sewage sludge, and
limestone screenings are all waste products of other
processes and are, therefore, usually inexpensive. The
major expense related to utilization of any of these wastes
is the cost of transporting and applying the material to the
mine area. Application may be quite costly and must be
uniform to effect complete and even revegetation.
When such large amounts of certain chemical nutrients are
utilized, it may also be necessary to institute controls to
prevent chemical pollution of adjacent waterways. Nutrient
controls may consist of preselection of vegetation to absorb
certain chemicals, or of construction of berms and retention
basins in which runoff can be collected and sampled, after
which it can be discharged or pumped back to the spoil. The
specific soil supplements and application rates employed are
selected to provide the best possible conditions for the
vegetative species that are to be planted.
Careful consideration should be given to species selection
in surface-mine reclamation. Species are selected according
to some land-use plan, based upon the degree of pollution
control to be achieved ana the site environment. A dense
ground cover of grasses and legumes is generally planted, in
addition to tree seedlings, to rapidly check erosion and
siltation. Trees are frequently planted in areas of poor
slope stability to help control landsliding. Intended
future use of the land is an important consideration with
respect to species selection. Reclaimed surface-mined lands
are occasionally returned to high-use categories, such as
agriculture, if the land has potential for growing crops.
However, when toxic spoils are encountered, agricultural
potential is greatly reduced, and only a few species will
grow.
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Environmental conditions—particularly, climate—are
important in species selection. Usually, specie? are
planted that are native to an area—particularly, species
that have been successfully established on nearby mine areas
with similar climate and spoil conditions.
Revegetation of arid and semi-arid areas involves special
consideration because of the extreme difficulty of
establishing vegetation. Lack of rainfall and effects of
surface disturbance create hostile growth conditions.
Because mining in arid regions has only recently been
initiated on a large scale, there is no standard
revegstation technology. Experimentation and demonstration
projects exploring two general revegetation techniques—
moisture retention and irrigation--are currently being
conducted to solve this problem.
Moisture retention utilizes entrapment, concentration, and
preservation of water within a soil structure to support
vegetation. This may be obtained utilizing snow fences,
mulches, pits, and other methods.
Irrigation can be achieved by pumping or by gravity, through
either pipes or ditches. This technique can be extremely
expensive, and acquisition of water rights may present a
major problem. Use of thesa arid-climate revegetation
techniques in conjunction with careful overburden
segregation and regrading should permit return of arid mined
areas to their natural states.
IxElQIltign, 5§¥§i°E!D§Qt• §J2<§ Pilot-Scale Operations
Exploration activities commonly employ drilling, blasting,
excavation, tunneling, and other techniques to discover,
locate, or define the extent of an ore body. These
activities vary from small-scale (such ag a single drill
hole) to large scale (such as excavation of an open pit or
outcrop face). Such activities frequently contribute to the
pollutant loading in waste water emanating from the site.
Since available facilities (such as power sources) and ready
accessibility of special equipment and supplies often are
limited, sophisticated treatment is often not possible. In
cases where exploration activity is being carried out, the
scale of such operations is such that primary water-quality
problems involve the presence of increased suspended-solid
loads and potentially severe pH changes. Ponds should be
provided for settling and retention of waste water, drilling
fluids, or runoff from the site. Simple, accurate field
tests for pH can be made, with subsequent pH adjustment by
addition of lime (or other neutralizing agents).
148
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Protection of receiving waters will thus be accomplished,
with the possible additional benefits of removal of metals
from solution—either in connection with solids removal or
by precipitation from solution.
Development operations frequently are large-scale, compared
to exploration activities, because they are intended to
extend already known or currently exploited resources.
Because these operations are associated with facilities and
equipment already in existence, it is necessary to plan
development activities to minimize pollution potential, and
to use existing mine or process facility treatment and
control methods and facilities. These operations should,
therefore, be subject to limitations equivalent to existing
operations with respect to effluent treatment and control.
Pilot-scale operations often involve small to relatively
large mining and beneficlarion facilities even though they
may not be currently operating at full capacity or are in
the process of development to full-scale. Planning of such
operations should be undertaken with treatment and control
of waste water in mind to ensure that effluent limitation
guidelines and standards of performance for the category or
subcategory will be met. Although total loadings from such
operations and facilites are not at the levels expected from
normal operating conditions, the compositions of wastes and
the concentrations of waste water parameters are likely to
be similar. Therefore, implementation of recommended
treatment and control technologies must be accomplished.
Mine and Process Facility, Closure
Mine Closure .(Underground),. Unless well-planned and well-
designed abatement techniques are implemented, an
underground mine can be a permanent source of water
pollution.
Responsibility for the prevention of any adverse
environmental impacts from the temporary or permanent
closure of a deep mine should rest solely and permanently
with the mine operator. This constitutes a substantial
burden; therefore, it behooves the operator to make use of
the best technology available for dealing with pollution
problems associated with mine closure. The two techniques
most frequently utilized in deep-mine pollution abatement
are treatment and mine sealing. Treatment technology is
well defined and is generally capable of producing
acceptable mine effluent quality. If the mine operator
chooses this course, he is faced with the prospect of costly
permanent treatment of each mine discharge.
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Mine sealing is an attractive alternative to the prospects
of perpetual treatment. Mine sealing requires the mine
operator to consider barrier and ceiling-support design from
the perspectives of strength, mine safety, their ability to
withstand high water pressure, and their utility for
retarding groundwater seepage. In the case of new mines,
these considerations should be included in the mine design
to cover the eventual mine closure. In the case of existing
mines, these considerations should be evaluated for existing
mine barriers and ceiling supports, and the future mine plan
should be adjusted to include these considerations if mine
sealing is to be employed at mine closure.
Sealing eliminates the mine discharge and inundates the mine
workings, thereby reducing or terminating the production of
pollutants. However, the possibility of the failure of mine
seals or outcrop barriers increases with time as the sealed
mine workings gradually became inundated by ground water and
the hydraulic head increases. Depending upon the rate of
ground-water influx and the size of the mined area, complete
inundation of a sealed mine may require several decades.
Consequently, the maximum anticipated hydraulic head on the
mine seals may not be realized for that length of time. In
addition, seepage through, or failure of, the barrier or
mine seal could occur at any time. Therefore, the mine
operator should be required to permanently maintain the
seals, or to provide treatment in the event of seepage or
failure.
Mine Closure .(Surface).. The objectives of proper
reclamation" management of closed surface mines and
associated workings are to (1) restore the affected lands to
a condition at least fully capable of supporting the uses
which they were capable of supporting prior to any mining,
and (2) achieve a stability which does not pose any threat
to public health, safety, or water pollution. With proper
planning and management during mining activities, it is
often possible to minimize, the amount of land disturbed or
excavated at any one time. In preparation for the day the
operation may cease, a reclamation schedule for restoration
of existing affected areas, as well as those which will be
affected, should be specified. The use of a planned
methodology such as this will return the workings to their
premined condition at a faster rate, as well as possibly
reduce the ultimate costs to the operator.
To accomplish the objectives of the desired reclamation
goals, it is mandatory that the surface-mine operator
regrade and revegetate the disturbed area during, or upon
completion of, mining. The final regraded surface
configuration is dependent upon the ultimate land use of the
specific site, and control practices described in this
150
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report, car. be incorporated into -the regrading plan to
minimize erosion and sedimentation. The operator should
establish a diverse and permanent vegetative cover and a
plant succession at least equal in extent, of cover to the
natural vegetation of the area. To assure compliance with
these requirements and permanence of vegetative cover, the
operator should be held responsible for successful revege-
tation and effluent water quality for a period of five full
years after the last year of augmented seeding. In areas of
the country where the annual average precipitation is 64 cm
(26 in.) or less, the operator's assumption of
responsibility and liability should ex-tend for a period of
ten full years after the last year of augmented seeding,
fertilization, irrigation, or effluent treatment.
Br.o.c.§§§ Utility. Ci2§H££- As with closed mines, a
beneficiation facility's potential contributions to water
pollution do not cease upon shutdown of the facility.
Tailing ponds, waste or refuse piles, haulage areas,
workings, dumps, storage areas, and processing and shipping
areas often present serious problems with respect to
contributions to water pollution. Among the most important
are tailing ponds, waste piles, and dump areas. Failure of
tailing ponds can have catastrophic consequences, with
respect to both immediate safety and water quality.
To protect against catastrophic occurrences, tailing ponds
should be designed to accommodate, without overflow, an
abnormal storm which is observed every 25 years. Since no
waste water is contributed from the processing of ores (the
facility being closed) , the ponds will gradually become
dewatered by evaporation or by percolation into the
subsurface. The structural integrity of the tailing-pond
walls should be periodically examined and, if necessary,
repairs made. Seeding and vegetation can assist in
stabilizing the walls, prevent erosion and sedimentation,
lessen the probability of structural failure, and improve
the aesthetics of the area.
Refuse, waste, and tailing piles should be recontoured and
revegetated to return the topography as near as possible to
the condition it was in before the activity. Techniques
employed in surface-mine regrading and revegetation should
be utilized. Where process facilities are located adjacent
to mine workings, the mines can be refilled with tailings.
Care should be taken to minimize disruption of local
drainage and to ensure that erosion and sedimentation will
not result. Maintenance of such refuse or waste piles and
tailing-disposal areas should be performed for at least five
years after the last year of regrading and augmented
seeding. In areas of the country where the annual average
precipitation is 6U cm (26 in.) or l^ss, the operator *s
151
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assumption of responsibility should extend for a period of
ten full years after the last year of augmented seeding,
fertilization, irrigation, or effluent treatment.
Monitoring
Since most waste water discharges from these industries
contain suspended solids as the principal pollutant, complex
water analyses are not usually required. On the other hand,
many of "these industries today do little or no monitoring on
waste water discharges. In order to obtain meaningful
knowledge and control of their waste water quality, many
mines and minerals processing facilities need to institute
routine monitoring measurements of the few pertinent waste
parameters.
SUSPENDED SOLIDS REMOVAL
The treatment technologies available for removing suspended
solids from minerals and mining waste water are numerous and
varied, but a relatively small number are used widely. The
following shows the approximate breakdown of usage for the
various techniques:
percent_of_treatment_facidities
removal_technigue usinc[_technology_
settling ponds (unlined) 95-97
settling ponds (lined) <1
chemical flocculation (usually 2-5
with ponds)
thickeners and clarifiers 1-2
hydrocyclones <1
tube and lamella settlers <1
screens <1
filters <1
centrifuges <1
Settling Ponds
As shown above, the predominant treatment technique for
removal of suspended solids involves one or more settling
ponds. Settling ponds are versatile in that they perform
several waste-oriented functions including:
(1) Solids removal. Solids settle to the bottom and the
clear water overflow is much reduced in suspended solids
content.
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(2) Equalization and water storage capacity. The clear
supernatant water layer serves as a reservoir for reuse
or for controlled discharge.
P) Solid waste storage. The settled solids are provided
with long term storage.
This versatility, ease of construction and relatively low
cost, explains the wide application of settling ponds as
compared to other technologies. The performance of these
ponds depends primarily on the settling characteristics of
the solids suspended, the flow rate through the pond and the
pond size. Settling ponds can be used over a wide range of
suspended solids levels. Often a series of ponds is used,
with the first collecting the heavy load of easily
settleable material and the following ones providing final
polishing to reach a desired final suspended level. As the
ponds fill with settled solids they can be either dredged to
remove these solids or left filled and new ponds
constructed. The choice often depends on whether land for
additional new ponds is available. When suspended solids
levels are low and ponds large, settled solids build up so
slowly that neither dredging nor pond abandonment is
necessary, at least not for a period of many years.
Settling ponds used in the minerals industry run the gamut
from small pits, natural depressions and swamp areas to
engineered thousand acre structures with massive retaining
dams and legislated construction design. The performance of
these ponds varies from excellent to poor, depending on
character of the suspended particles, and pond size and
configuration. In general the suspended solids levels from
the final pond can be reduced to 10 to 30 mg/1. Waste
waters containing significant amounts of hydrophilic
colloids, such as montmorillonite, are especially difficult
to clarify.
Much of the poor performance exhibited by the settling ponds
employed by -che minerals industry is due to the lack of
understating of settling techniques. This is demonstrated
by the construction of ponds without prior determination of
settling rare and detention time. In some cases series of
ponds have been claimed to demonstrate a company's
mindfullness of environmental control when in fact all the
component ponds are so poorly constructed and maintained
that they could be replaced by one pond with less surface
area than the total of the series.
The chief problems experienced by settling ponds are rapid
fill-up, insufficient retention time and the closely related
short ciruciting. The first can be avoided by constructing
a series of ponds as mentioned above. Frequent dredging of
153
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the first if needed will reduce the need to dredge the
remaining ponds. The solution to the second involves
additional pond volume or use of flocculants. The third
problem, however, is almost always overlooked. Short
circuiting is simply the formation of currents or water
channels from pond influent to effluent whereby whole areas
of the pond are not utilized. The principles of clarifier
construction apply here. The object is to achieve a uniform
plug flow from pond influent to effluent. This can be
achieved by proper inlet-outlet construction that forces
water to be uniformly distributed at those points, such as
a weir. Frequent dreding or insertion of baffles will also
minimize channelling. The EPA report "Waste water Treatment
Studies in Aggregate and Concrete Production" (reference 25)
in detail lists the procedure one should follow in designing
and building settling ponds.
Clarifiers and Thickeners
An alternative method of removing suspended solids is the
use of Clarifiers or thickeners which are essentially tanks
with internal baffles, compartments, sweeps and other
directing and segregating mechanisms to provide efficient
concentration and removal of suspended solids in one
effluent stream and clarified liquid in the other.
Clarifiers differ from thickeners primarily in their basic
purpose. Clarifiers are used when the main purpose is to
produce a clear overflow with the solids content of the
sludge underflow being of secondary importance. Thickeners,
on the other hand, have the basic purpose of producing a
high solids underflow with the character of the clarified
overflow being of secondary importance. Thickeners are also
usually smaller in size but more massively constructed for a
given throughput. Clarifiers and thickeners have a number
of distinct advantages over ponds:
(1) Less land space is required. Area-for-area these
devices are much more efficient in settling capacity
than ponds .
(2) Influences of rainfall are much less than for ponds. If
desired the Clarifiers and thickeners can even be
covered.
(3) Since the external construction of Clarifiers and
thickeners consists of concrete or steel tanks ground
seepage and rain water runoff influences do not exist.
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On the other hand, clarifiers and thickeners suffer some
distinct disadvantages as compared with ponds:
(1) They have more mechanical parts and maintenance.
(2) They have only limited storage capacity for either
clarified water or settled solids.
(3) The internal sweeps and agitators in thickeners and
clarifiers require more power and energy for operation
Clarifiers and thickeners are usually used when sufficient
land for ponds is not available or is very expensive.
Hydrocyclones
While hydrocyclones are widely used in the separation, clas-
sification and recovery operations involved in minerals
processing, they are used only infrequently for waste water
treatment. Even the smallest diameter units available
(stream velocity and centrifugal separation forces both
increase as the diameter decreases) are ineffective when
particle size is less than 25-50 microns. Larger particle
sizes are relatively easy to settle by means of small ponds,
thickeners or clarifiers or other gravity principle settling
devices. It is the smaller suspended particles that are the
most difficult to remove and it is these that can not be
removed by hydrocyclones but may be handled by ponds or
other settling technology. Also hydrocyclones are of
doubtful effectiveness when flocculating agents are used to
increase settling rates.
Hydrocyclones are used as scalping units to recover small
sand or o-ther mineral particles in the 25 to 200 micron
range, particularly if the recovered material can be sold as
product. In this regard hydrocyclones may be considered as
converting part of the waste load to useful product as well
as providing the first step of waste water treatment. Where
land availability is a problem a bank of hydrocyclones may
serve in place of a primary settling pond.
Tube and Lamella Settlers
Tube and lamella settlers require less land area than
clarifiers and thickeners. These compact units, which
increase gravity settling efficiency by means of closely
packed inclined tubes and plates, can be used for either
scalping or waste water polishing operations depending on
throughput and design.
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Centrifuges
Centrifuges are not widely used for minerals mining waste
water treatment. Present industrial-type centrifuges are
relatively expensive and not particularly suited for this
purpose. Future use of centrifuges will depend on
regulations, land space availability and the development of
specialized units suitable for minerals mining operations.
Flocculation
Flocculating agents increase the efficiency of settling
facilities and they are of two general types: ionic and
polymeric. The ionic types such as alum, ferrous sulfate
and ferric chloride function by neutralizing the repelling
double layer ionic charges around the suspended particles
and thereby allowing the particles to attract each other and
agglomerate. Polymeric types function by forming physical
bridges from one particle to another and thereby
agglomerating the particles. Flocculating agents are most
commonly used after the larger, more readily settled,
particles (and loads) have been removed by a settling pond,
hydrocyclone or other such scalping treatment.
Agglomeration, or flocculation, can then be achieved with
less reagent and less settling load on the polishing pond or
clarifier.
Flocculation agents can be used with minor modifications and
additions to existing treatment systems, but the costs for
the flocculating chemicals are often significant. Ionic
types are used in 10 to 100 mg/1 concentrations in the waste
water while the higher priced polymeric types are effective
in the 2 to 20 mg/1 concentrations. Flocculants have been
used by several segments within the minerals industry with
varying degrees of success. The use of flocculants
particularly for the hard to settle solids is more of an art
than a science, since it is frequently necessary to try
several flocculants at varying concentrations.
Screens
Screens are widely used in minerals and mining processing
operations for separations, classifications and
beneficiations. They are similar to hydrocyclones in that
they are restricted to removing the larger (<50-100 micron)
particle size suspended solids of the waste water, which can
then often be sold as useful product. Screens are not
practical for removing the smaller suspended particles.
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Filtration
Filtration is accomplished by passing the waste water stream
through solids-retaining screens, cloths, or particulates
such as sand, gravel, coal or diatomaceous earth using
gravity, pressure or vacuum as the driving force.
Filtration is versatile in that it can be used to remove a
wide range of suspended particle sizes. The large volumes
of many waste water streams found in minerals mining
operations require large filters. The cost of these units
and their relative complexity, compared to settling ponds,
has restricted their use to a few industry segments
committed to complex waste water treatment.
DISSOLVED MATERIAL TREATMENTS
Dissolved materials are a problem only in scattered
instances in the industries covered herein. Treatments for
dissolved materials are based on either modifying or
removing the undesired materials. Modification techniques
include chemical treatments such as neutralization and
oxidation-reduction reactions. Acids, alkaline materials,
sulfides and other toxic or hazardous materials are examples
of dissolved materials modified in this way. Most removal
of dissolved solids is accomplished by chemical
precipitation. Techniques such as ion exchange, carbon
adsorption, reverse osmosis and evaporation are rarely used
in the minerals mining industry. Chemical treatments for
abatement of water-borne wastes are common. Included in
this overall category are neutralization, pH control,
oxidation-reduction reactions, coagulations, and
precipitations.
Neutralization
Some of the waste waters of this srudy, often including mine
drainage water, are either acidic or alkaline. Before
disposal to surface water or other medium excess acidity or
alkalinity needs to be controlled to the range of pH 6 to 9.
The most common method is to treat acidic streams with
alkaline materials such as limestone, lime, soda ash, or
sodium hydroxide. Alkaline streams are treated with acids
such as sulfuric. Whenever possible, advantage is taken of
the availability of acidic waste streams to neutralize basic
waste streams and vice versa. Neutralization often produces
suspended solids which must be removed prior to waste water
disposal.
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pH Control
The control of pH may be equivalent to neutralization if the
control point is at or close to pH 7. Sometimes chemical
addition to waste streams is designed to maintain a pH level
on either the acidic or basic side for purposes of
controlling solubility. Examples of pH control being used
for precipitating undesired pollutants are:
(1) Fe+a + 3OH- = Fe(OH)3
(2) Mn+z + 2OH- = Mn (OH) 2. = MnO2 + 2H+ + 4e~
(3) Zn+2 + 20H- = Zn (OH) 2
(4) Pb+z + 2 (OH)- = Pb(OH)2
(5) Cu * 20H- = Cu(OH)2-
Reaction (1) is used for removal of iron contaminants.
Reaction (2) is used for removing manganese from manganese-
containing water-borne wastes. Reactions (3), (4), and (5)
are used on waste water containing copper, lead, and zinc
salts.
Oxidation-Reduction Reactions
The modification or destruction of many hazardous wastes is
accomplished by chemical oxidation or reduction reactions.
Hexavalent chromium is reduced to the less hazardous triva-
lent form with sulfur dioxide or bisulfites. Sulfides, with
large COD values, can be oxidized with air to relatively
innocuous sulfates. These examples and many others are
basic to the modification of inorganic chemical water-borne
wastes to make them less troublesome. In general waste
materials requiring oxidation- reduction treatments are not
encountered in these industries.
Precipitations
The reaction of two soluble chemicals to produce insoluble
or precipitated products is the basis for removing many
undesired water-borne wastes. The use of this technique
varies from lime treatments to precipitate sulfates,
fluorides, hydroxides and carbonates to sodium sulfide
precipitations of copper, lead and other toxic heavy metals.
Precipitation reactions are particularly responsible for
heavy suspended solids loads. These suspended solids are
removed by settling ponds, clarifiers and thickeners,
filters, and centrifuges.
158
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The following are examples of precipitation reactions used
for waste water treatment:
(1) S04= + Ca(OH)2 = CaSOjl + 2OH-
(2) 2F- + Ca(OH)2 = CaF2 + 2OH~
(3) Zn++ + Na2CO3 = ZnCO3 + Na+
SUMMARY OF TREATMENT TECHNOLOGY APPLICATIONS, LIMITATIONS
AND RELIABILITY
Table 6 summarizes comments on the various treatment
technologies as they are utilized for the minerals and
mining industry. Estimates of the efficiency with which the
treatments remove suspended or dissolved solids from waste
water, given in Table 6 need to be interpreted in the
following context. These values will obviously not be valid
for all circumstances, concentrations or materials, but they
should provide a general guideline for treatment performance
capabilities. Several comments may be made concerning the
values:
(1) At high concentrations and optimum conditions, all
treatments can achieve 99 percent or better removal of
the desired material;
(2) At low concentrations, the removal efficiency drops off.
(3) Minimum concentration ranges achievable will not hold in
every case. For example, pond settling of some
suspended solids might not achieve less than the
100 mg/1 level. This is not typical, however, since
many such pond settling treatments can achieve 10 to
20 mg/1 without difficulty. Failure to achieve the
minimum concentration levels listed usually means that
either the wrong treatment methods have been selected or
that an additional treatment step is necessary (such as
a second pond or filtration) .
PRETREATMENT TECHNOLOGY
Mineral mining operations are usually conducted in
relatively isolated regions where there is no access to
publicly-owned activated sludge or trickling filter waste
water treatment facilities. In areas where publicly-owned
facilities could be used, pretreatment would often be
required to reduce the heavy suspended solids load. In the
relatively few instances where dissolved materials are
serious, pH control and some reduction of hazardous cons-
tituents such as fluorides and heavy metals would be
159
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Table 6. Summary of Technology, Applications, Limitations & Reliability
w«t.
Wottr
Const! tuonti
MWi
i
1
Solid,
TMta*.
(l)Pond
{•tiling
(7) Ckrlfltr
(3) Hydrc-
tycfonet
(•fl Tuba and
la**Ha
Sottlin
(5)ScnMn
(o)lolory
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Nlrm
(7) Solid twl
(QUoTond
PrtBuro
(9)C«lrldg.
ond Condi.
Flrlm
PO)Sondond
M«flo
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(1) KUulroll-
kolFofl ond
pH Control
(7) Pftetptfa-
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Ui.d for oil
pa/ttd« tim
famoval of vnoll.r
porticlo ll'««
lumval of lo>B«
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Mainly far iludaM
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luipandod lolfdi
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and othar high
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conctntratlon
rong.
Mainly for polic-
ing filtrotlom of
•uipflndcd saiidi
Mainly Tor polTrfw
ing flltrotioni of
iuip«nd«d loll^fl
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»0-»9
tO-99
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SM,
90-99
40-99
90-99
30-W
50-W
79
50-99
Concen-
tration
wn
5-200
5-1000
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-
10-100
2-10
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unall
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Molrt.o-
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lUqulrnl
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nonlnal
mall
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nominal
nomlnaE
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undl
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itmitlv«
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nominaE
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nominal
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nominal
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"""
160
-------
required. Lime treatment will usually be sufficient for
reductions of both categories.
NON-WATER QUALITY ENVIRONMENTAL ASPECTS, INCLUDING ENERGY
REQUIREMENTS
The effects of these treatment and control technologies on
air pollution, noise pollution, and radiation are usually
small and not of any significance. Large amounts of solid
waste in the form of both solids and sludges are formed as a
result of all suspended solids operations as well as
chemical treatments for neutralization, and precipitations.
Easy-to-handle, relatively dry solids are usually left in
settling ponds or dredged out periodically and dumped onto
the land. Since mineral mining properties are usually
large, space for such dumping is often available. Sludges
and difficultly settled solids are most often left in the
settling pond, but may in some instances be landfilled.
For those waste materials considered to be non-hazardous
where land disposal is the choice for disposal, practices
similar to proper sanitary landfill technology may be
followed. The principles set forth in the EPA's Land
Disposal of Solid Wastes Guidelines (CFR Title UO, Chapter
1; Part 241) may be used as guidance for acceptable land
disposal techniques.
For those waste materials considered to be hazardous,
disposal will require special precautions. In order to
ensure long-term protection of public health and the
environment, special preparation and pretreatment may be
required prior to disposal. If land disposal is to be
practiced, these sites must not allow movement of pollutants
such as fluoride and radium-226 to either ground or surface
water. Sites should be selected that have natural soil and
geological conditions to prevent such contamination or, if
such conditions do not exist, artificial means (e.g.,
liners) must be provided to ensure long-term protection of
the environment from hazardous materials. Where
appropriate, the location of solid hazardous materials
disposal sites should be permanently recorded in the
appropriate office of the legal jurisdiction in which the
site is located. In summary, the solid wastes and sludges
from the mineral mining industry waste water treatments are
very large in quantity, but the industry, having sufficient
space and earth-moving capabilities, manages it with greater
ease than could most other industries.
For the best practicable control technology currently
available the added annual energy requirements are estimated
at 1.6 x 108 kcal. This would increase the present energy
161
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use for pollution control in this industxy by less than one
percent.
162
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SECTION VIII
1N ERG Yx WASTE, REDUCTION BENEFITS ..AND NON-WATER, ASPECTS
OF'TREATMENT AND CONTROL TECHNOLOGIES
SUMMARY
The clay, ceramic, refractory and miscellaneous minerals
segment of the mineral mining and processing industry is
characterized by individuality of facilities. Unlike
manufacturing operations, where raw materials for the
process may be selected and controlled as to purity and
uniformity, mining and minerals processing operations are
themselves largely controlled by the purity and uniformity
of the ores or raw materials involved. Operations have to
be located, at or near the mineral deposits. This lack of
control over raw material quality and location, coupled with
the fact that both mines and ore beneficiation processes may
have waste water effluents, leads to several basic treatment
costing differences from those for manufacturing operations:
(1) In order to achieve reasonable homogeneity,
industries have to be segregated into subcategories
such as wet mines, dry mines, dry processes and one
or more wet processes.
(2) Solid waste loads vary widely depending on ore
composition.
(3) Types of water-borne waste vary with ore and
process. Processes are modified according to ore
composition.
(<4) Treatment costs often vary widely depending on
character of pollutants involved. The most
widespread example is particle size and composition
variation of suspended solids. Deposits with large
particle sized wastes have high settling rates
while small or colloidal suspended particles are
slow and difficult to settle, requiring large
ponds, thickeners, flocculating treatments, other
devices for removing suspended solids in many
cases.
In general, facility size and age have little influence on
the type of waste effluent. The amounts and costs for their
treatment and disposal are readily scaled from facility size
and are not greatly affected by facility age.
163
-------
Geographical location is important. Mines and processing
facilities located in dry western areas rarely require major
waste water treatment or have subsequent disposal problems.
Terrain and land availability are also significant factors
affecting treatment technology and costs. Lack of
sufficient flat space for settling ponds often forces
utilization of mechanical thickeners, clarifiers, or
settlers. On the other hand, advantage is often taken of
valleys, hills, swamps, gullies and other natural
configurations to provide low cost pond and solid waste
disposal facilities.
In view of the large number of mines and beneficiation
facilities and the significant variables listed above, costs
have been developed for representative mines and processing
facilities rather than specific exemplary facilities that
may have advantageous geographical, terrain or ore
composition.
A summary of cost and energy information for the present
level of waste water treatment technology for this segment
is given in Table 7. Present capital investment for waste
water treatment in the clay, ceramic, refractory and
miscellaneous minerals segment is estimated at $7,500,000.
COST REFERENCES AND RATIONALE
Cost information contained in this report was assembled
directly from industry, from waste treatment and disposal
contractors, engineering firms, equipment suppliers,
government sources, and published literature. Whenever
possible, costs are taken from actual installations,
engineering estimates for projected facilities as supplied
by contributing companies, or from waste treatment and
disposal contractors quoted prices. In the absence of such
information, cost estimates have been developed insofar as
possible from facility-supplied costs for similar waste
treatments and disposal for other facilities or industries.
Interest Costs and Equity Financing Charges
Capital investment estimates for this study have been based
on 10 percent cost of capital, representing a composite
number for interest paid or return on investment required.
Time Basis for Costs
All cost estimates are based on August 1972 prices and when
necessary have been adjusted to this basis using the
chemical engineering facility cost index.
164
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TABLE 7
CAPITAL INVESTMENTS AND ENERGY CONSUMPTION OF PRESENT WASTEWATER
TREATMENT FACILITIES
Capital Spent
Subcategory Dollars
Present Energy
Use -
KcalxlCT
Total Annual
Costs -$/kkg
Produtjgd
Bentonite
Fire Clay
Attapulgite )
Montmorillonite)
Kaolin (dry process)
Kaolin (wet process)
Ball Clay
Feldspar (dry process)
Feldspar (flotation)
Kyanite
Magnesite
Shale
Aplite
Talc minerals (dry)
Talc minerals (wet
washing)
Talc minerals (heavy
media flotation)
Abrasives, Garnet
Abrasives, Tripoli
Diatomite
Graphite
Jade
Novaculite
TOTAL
335,000
450,000
370,000
500,000
<100,000
1,000
negligible
7,500,000
No Waste Water
No Waste Water
$ 330,000
2,670,000
335,000
1,000,000
375,000
300,000
695,000
180
No Waste Water
6,875
825
No Waste Water
4,950
830
small
No Waste Water
2,230
No Waste Water
0.22
0.29
0.26
1.65
2.83
0.19
0.69
1,670
1.09
2,500 1.09
1,250 5.88
No Waste Water (except one scrubber)
small 0.27
small $20-25
negligible negligible
negligible negligible
21,300
165
-------
Useful Service Life
The useful service life of treatment and disposal equipment
varies depending on the nature of the equipment and process
involved, its usage pattern, maintenance care and numerous
other factors. Individual companies may apply service lives
based on their actual experience for internal amortization.
Internal Revenue Service provides guidelines for tax
purposes which are intended to approximate average
experience. Based on discussions with industry and
condensed IRS guideline information, the following useful
service life values have been used:
(1) General process equipment 10 years
(2) Ponds, lined and unlined 20 years
(3) Trucks, bulldozers, loaders
and other such materials
handling and transporting
equipment. 5 years
Depreciation
The economic value of treatment and disposal equipment and
facilities decreases over its service life. At the end of
the useful life, it is usually assumed that the salvage or
recovery value becomes zero. For IRS tax purposes or
internal depreciation provisions, straight line, or
accelerated write-off schedules may be used. straight line
depreciation was used solely in this report.
Capital Costs
Capital costs are defined as all front-end out-of-pocket
expenditures for providing ' treatment/disposal facilities.
These costs include costs for research and development
necessary to establish the process, land costs when
applicable, equipment, construction and installation,
buildings, services, engineering, special start-up costs and
contractor profits and contingencies.
Annual Capital Costs
Most if not all of the capital costs are accrued during the
year or two prior to actual use of the facility. This
present worth sum can be converted to equivalent uniform
annual disbursements by utilizing the Capital Recovery
Factor Method:
166
-------
Uniform Annual Disbursement = P i (1 + ilnth power
(1 + i)nth power - 1
Where P = present value (capital expenditure), i =
interest rate, %/100, n = useful life in years
The capital recovery factor equation above may be
rewritten as:
Uniform Annual Disbursement = P (CR - i% - n)
Where (CR - i% - n) is the Capital Recovery Factor for
i% interest taken over "n" years useful life.
Land Costs
Land-destined solid wastes require removal of land from
other economic use. The amount of land so tied up will
depend on the treatment/disposal method employed and the
amount of wastes involved. Although land is non-depreciable
according to IRS regulations, there are numerous instances
where the market value of tn»e land for land-destined wastes
has been significantly reduced permanently, or actually
becomes unsuitable for future use due to the nature of the
stored waste. The general criteria applied to costing land
are as follows:
(1) If land requirements for on-site treatment/disposal are
not significant, no cost allowance is applied.
(2) Where on-site land requirements are significant and the
storage or disposal of wastes- does not affect the
ultimate market value of the land, cost estimates
include only interest on invested money.
(3) For significant on-site land requirements where the
ultimate market value and/or availability of the land
has been seriously reduced, cost estimates include both
capital depreciation and interest on invested money.
(U) off-site treatment/disposal land requirements and costs
are not considered directly. It is assumed that land
costs are included in the overall contractor's fees
along with its other expenses and profit.
(5) In view of the extreme variability of land costs,
adjustments have been made for individual industry
situations. In general, isolated, plentiful land has
been costed at $2,<»70/hectare ($1,000/acre) .
Operating Expenses
Annual costs of operating the treatment/disposal facilities
include labor, supervision, materials, maintenance, taxes,
insurance and power and energy. Operating costs combined
with annualized capital costs give the total costs for
167
-------
treatment and disposal operations. No interest cost was
included for operating (working) capital. Since working
capital might be assumed to be one sixth to one third of
.annual operating costs (excluding depreciation) , about
1-2 percent of total operating costs might be involved.
This is considered to be well within the accuracy of the
estimates.
Rationale for Representative Facilities
All facility costs are estimated for representative
facilities rather than for any actual facility.
Representative facilities are defined to have a siza and age
agreed upon by a substantial fraction of the manufacturers
in the subcategory producing the given mineral, or, in the
absence of such a consensus, the arithmetic average of
production size and age for all facilities. Location is
selected to represent the industry as closely as possibly.
For instance, if all facilities are in northeastern U.S.,
typical location is noted as "northeastern states". If
locations are widely scattered around the U.S., typical
location would be not specified geographically. If two
facilities exist, one on the west coast and one on the east
cost, • typical location would be M1 east coast - 1 west
coast". It should be noted that the unit costs to treat and
dispose of hazardous wastes at any given facility may be
considerably higher or lower than the representative
facility because of individual circumstances.
Definition of Levels of Treatment and Control
Costs are developed for various types and levels of
technology:
MiniiTtuin Jor basic levelj_ is that level of technology which
is equalled or exceeded by most or all of the involved
facilities. Usually money for this treatment level has
already been spent (in the case of capital investment) or is
being spent (in the case of operating and overall costs) .
lxCj.DAE --- Levels are successively greater degrees of
treatment with respect to critical pollutant parameters.
Two or more alternative treatments are developed when
applicable.
Rationale for Pollutant Considerations
(1) All non-contact cooling water is exempted from treatment
(and treatment costs) provided that it is not
contaminated by process water and no harmful pollutants
are introduced.
168
-------
(2) Water treatment, cooling tower and boiler blowdown
discharges are not treated provided they are not
contaminated by process water and contain no harmful
pollutants.
(3) Removal of dissolved solids, other than harmful
pollutants, is not included because of high cost
factors.
(4) Mine drainage treatments and costs are considered
separately from process water treatment and costs. Mine
drainage costs are estimated for all mineral categories
for which such costs are a significant factor.
(5) All solid waste disposal costs are included as part of
the cost development .
Cost Variances
The effects of age, location, and size on costs for
treatment and control have been considered and are detailed
in subsequent sections for each specific subcategory.
INDUSTRY STATISTICS
Following are summarized the estimated 1972 selling prices
for the individual minerals covered in this report. These
values were taken from minerals industry yearbooks and
Bureau of Census publications.
Bentonite 11.70 10.60
Fire Clay 9.00 8.15
Fuller's Earth 25.50 23.00
Kaolin 28.40 25.75
Ball Clay 17.65 16.00
Feldspar 22-28 24-31
Kyanite 70.50 64.00
Magnesite 165 150
Shale 6 Misc. Clay 1.76 1.60
Aplite not known
Talc Minerals 34 31
Abrasives, Garnet 114 103
Abrasives, Tripoli 10 9
Diatomite 72 65
Graphite withheld
Jade 22,000 20,000
after cutting
Novaculite 66 60
169
-------
INDIVIDUAL WASTE WATER TREATMENT
COSTS
BENTONITE
There is no waste water from the processing of bentonite.
Therefore, there is no treatment cost involved.
FIRE CLAY
The only waste water from mining and processing of fire clay
is mine water discharge. Treatment costs for settling
suspended solids in mine water are estimated at
$0.01-0.05/kkg of produced fire clay. Since there is no
process water discharge in the production of fire clay,
there are no costs for process waste water treatment.
FULLER'S EARTH
Fuller's earth was divided into two subcategories
attapulgite and montmorillonite. Suspended solids in
attapulgite mine drainage and process water generally settle
rapidly. Suspended solids in montmorillonite mine drainage
and process water are more difficult to settle.
Estimates of treatment costs for mine water, including use
of flocculating agents to settle montmorillonite wastes,
range from JO.17 to $0.28/kkg of montmorillonite produced,
s=e Table 10.
process and air scrubber waste water treatment costs are
summarized in Tables 8 and 9.
Cost Variance
Age
In the montmorillonite subcategory, there are three
facilities ranging in age from 3 to 18 years. Age is not a
significant factor in cost variance.
There are four facilities representing the attapulgite
subcategory ranging in age from 20 to 90 years. Age is not
a significant factor in cost variance.
Location
All the facilities in the montmorillonite subcategory are
located in Georgia and, thus, location is not a significant
factor in cost variance.
The attapulgite facilities are located in Georgia and
Florida, in close proximity and therefore, location is not a
significant factor in cost variance.
170
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COST
TABLE 8
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUBCATE60RY Attapulgite (Process Water Only)
PLANT SIZE 200,000
METRIC TONS PER YEAR OF Attapulgite
PLANT AGE 60 YEARS
PLANT LOCATION
Georgia-North Florida Region
INVESTED CAPITAL COSTS!
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 8 M {EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/ METRIC TON Attopulqite
WASTE LOAD PARAMETERS
(kg /metric ton of )
TSS
PH
RAW
WASTE
LOAD
LEVEL
A
(MINI
71 , 000
8,400
37,400
200
46,000
0.21
0.01-0.02
6-9
B
77,000
9,300
39,800
200
49,300
0.22
0.01
6-9
C
95,000
11,100
39, 1 00
300
50,500
0.23
0
_
D
E
LEVEL DESCRIPTION:.
A — pond settling
B — A plus flocculating agents
C — B plus recycle to process
171
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COST
TABLE 9
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUBCATEGORY Montmorillonite (Process Wafer Only)
PLANT SIZE
182,000
PLANT AGE 10 YEARS
METRIC TONS PER YEAR OF Montmorlllonite
Georgia
PLANT LOCATION
INVESTED CAPITAL COSTS!
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 a M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/METRIC TON Moftfomnrillonfff
WASTE LOAD PARAMETERS
(kg/metric ton of montmorilldr
TSS
PH
RAW
WASTE
LOAD
He)
LEVEL
A
(MIN)
60,000
7,000
30,900
200
38,100
0.21
0.3
6-9
B
65,000
7,900
32,900
200
41,000
0.22
0.05
6-9
C
80,000
9,400
32,300
300
43,000
0.24
0
-
D
E
LEVEL DESCRIPTION:
A — pond settling of scrubber water
B — A plus flocculating agents
C — B plus recycle to process
172
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COST
TABLE 10
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUBCATEGORY Montmorillonite (Mine Wgter Only)
PLANT SIZE 182,000 METRIC TONS PER YEAR OF Montmorillonite
PLANT AGE 10 YEARS
PLANT LOCATION Georgia
INVESTED CAPITAL COSTS'.
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 & M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/METRIC TONMontmoriilomte
WASTE LOAD PARAMETERS
(kq /metric ton of )
TSS, mg/liter
RAW
WASTE
LOAD
LEVEL
A
(MIN)
0
0
0
0
0
0
200—
5,000
B
60,000
15,800
12,300
3,000
32,300
0.17
2uO—
2,000
c
62,000
16,300
32,300
3,000
51,800
0.28
<50
D
E
LEVEL DESCRIPTION
A — no treatment
B — pond settling
C — B plus flocculating agents
173
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Size
The facilities in the montmorillonite subcategory range from
13,600 to 207,000 kg/yr (15,000-228,000 ton/yr) '. The
representative facility is 182,000 kkg/yr (200,000 ton/yr).
The attapulgite facilities range from 21,800 kkg/yr (2*4,000
ton/yr) and 227,000 kkg/yr (250,000 ton/yr). The
representative facility is 200,000 kkg/yr (220,000 ton/yr).
In both these subcategories the cost variance with size is
estimated to be a 0.9 exponential function for capital and
its related annual costs, and directly proportional for
operating costs other than taxes, insurance and capital
recovery.
Cost Basis for Table 8.
Capital Costs
Pond cost, $/hectare ($/acre): 24,700 (10,000)
Mine pumpout settling pond area, hectares (acres):0.1 (0.25)
Process Settling pond area, hectares (acres):2 (5)
Pumps and pipes: $10,000
Operating and Maintenance Costs
Energy unit cost: $0.01/kwh
Labor rate assumed; $10,000/yr
Cost Basis for Table 9.
Capital Costs
Pond cost, I/hectare ($/acre):2U,700 (10,000)
Mine pumpout settling pond hectares (acres):0.1 (0.25)
Process settling pond area, hectares (acres):2 (5)
Pumps and pipes: $10,000
Operating and Maintenance Costs
Treatment chemicals
Flocculating agent: $1.50/kg ($0.70/lb)
Energy unit cost: $0.01/kwh
Labor rate assumed: $!0,OCO/yr
174
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KAOLIN AND BALL CLAY
Kaolin and ball clay mining and processing operations differ
widely as to their waste water effluents. All treatments
involve settling ponds for their basic technology. Dry
mines need no treatment or treatment expenditures. Wet
mines (from rain water and ground seepage) use settling
ponds to reduce suspended solids. These settling ponds are
small and cost an estimated $0.01-$0.06/kkg of clay product.
Processing facilities may be either wet or dry. Dry
facilities have no treatment or treatment costs. Wet
processing facilities have process waste water from two
primary sources: scrubber water from air pollution
facilities, and process water that may contain zinc compound
from a product bleaching operation.
Scrubber and process water need to be treated to reduce
suspended solids and zinc compounds. costs for reduction
are summarized in Tables 11 and 12 for wet process kaolin
and ball clay, respectively.
Cost Variance
Age
The kaolin wet process subcategory consists of two
facilities having ages of 29 and 37 years. Age is not a
cost variance factor.
The ball clay subcategory has a range of facility ages from
15 to 56 years. Age has not been found to be a significant
factor on costs.
Location
The wet process kaolin operations are only located in
Georgia, hence not a variance.
Ball clay operations are located in the Kentucky-Tennessee
rural areas and hence location is not a significant cost
variance factor.
Size
The two wet process kaolin facilities are 300,000 and
600,000 kkg/yr (330,000 and 650,000 ton/yr) size. The
representative facility is 450,000 kkg/yr (500,000 ton/yr).
Capital costs over this size range are estimated to be a 0.9
exponential function of size, and operating costs other than
taxes, insurance, and capital recovery are estimated to be
proportional to size.
175
-------
COST
SUBCATEGORY Wet Process Kaolin
TABLE 11
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
PLANT SIZE 450,000
PLANT AGE 30 YEARS
METRIC TONS PER YEAR OF Kaolin
PLANT LOCATION Georgia-South Carolina
INVESTED CAPITAL COSTS.'
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 8 M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/METRIC TON of Kaolin
WASTE LOAD PARAMETERS
(ka /metric ton of Kaolin )
TS5
Dissolved zinc
PH
RAW
WASTE
LOAD
35-100
0.4
LEVEL
A
(MIN)
447,000
49,200
85,000
5,000
1 39, 200
0.31
0.02-0.2
0.001
6-9
B
463,000
51,800
112,000
5,000
168,800
0.38
<0.1
0.001
6-9
C
487,000
55,600
90,000
5,000
152,200
0.34
0
0
—
D
E
LEVEL DESCRIPTION:
A — pond settling with lime treatment
B — A plus flocculating agents
C — pond settling and recycfe to process (This should be satisfactory for cases where
only cooling water and scrubber water are present. Process water will build up
dissolved solids, requiring a purge.)
176
-------
COST
TABLE 12
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUBCATEGORY Boll Clay
PLANT SIZE 75,000
PLANT AGE 30 YEARS
METRIC TONS PER YEAR OF Ball Clay
PLANT LOCATION Kentucky-Tennessee Region
INVESTED CAPITAL COSTS:
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 G M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/ METRIC TON of Ball Clay
WASTE LOAD PARAMETERS
(kg /metric Ion of ball clay )
TS-S
pH
RAW
WASTE
LOAD
LEVEL
A
(M1N)
39,000
9,800
14,000
800
24,600
0.33
0.4-2.0
6-9
B
92,000
10,300
19,000
800
30,100
0.40
0.2
6-9
C
97,000
1 1 , 1 00
15,000
1,100
27,200
0.36
0
-
D
E
LEVEL DESCRIPTION:
A — pond settling
B — A plus flocculating agent
C — closed cycle operation (satisfactory only for scrubbers and cooling water)
L77
-------
The ball clay facilities range from 3,000 to 113,000 kkg/yr
(3,300 to 125,000 ton/yr)„ The representative facility is
68,000 kkg/yr (75,000 ton/yr). Capital cost and operating
cost variance factors for size are the same as for wet
process kaolin above.
Cost Basis for Table 11
Capital Costs
Pond cost, $/hectare ($/acre):12,350 (5,000)
Settling pond area, hectares (acres):20 (50)
Pumps and pipes: $25,000
Chemical metering equipment*. $10,000
Operating and Maintenance Costs
Pond dredging: $20,QOO/yr
Treatment chemicals
Lime: $22/kkg (120/ton)
Flocculating agent: $2.2/kg ($1/lb)
Energy unit cost: $0.01/kwh
Maintenance: $10,000-11,000/yr
cost Basis for Table 12
Capital costs
Land cost, S/hectare ($/acre): 12,350 (5,000)
Settling pond area, hectares (acres): 20 (50)
Pumps and pipes: f25,000
Chemical metering equipment: $10,000
Qperating and Maintenance Costs
Pond dredging: ?2Q,000/yr
Treatment chemicals
Lime: $22/kkg ($20/ton)
Flocculating agent: $2.2/kg ($1/lb)
Maintenance: $10,000-11,000/yr
178
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FELDSPAR
Feldspar may be produced as the sole product, as the main
product with by-product sand and mica, or as a co-product of
processes for producing mica. Co-product production
processes will be discussed under mica. Dry processes (in
western U.S.) where feldspar is the sole product have no
water effluent and no waste water treatment costs.
Therefore, the only subcategory involving major treatment
and cost is wet beneficiation of feldspar ore.
After initial scalpings with screens, hydrocyclones or other
such devices to remove the large particle sizes, the smaller
particle sizes are removed by (1) settling ponds or
(2) mechanical thickeners, clarifiers and filters. Often
the method selected depends on the amount and type of land
available for treatment facilities. Where sufficient flat
land is available ponds are usually preferred.
Unfortunately, most of the industry is located in hill
country and flat land is not available. Therefore,
thickeners and filters are often used. Waste water from the
feldspar beneficiation involves as primary pollutants
suspended solids and fluorides. There is also a solid waste
disposal problem for ore components such as mud, clays and
some types of sand, some of which have to be landfilled.
Fluoride pollutants come from the hydrofluoric acid
flotation reagent.
Treatment and cost options are developed in Table 13 for
both suspended solids and fluoride reductions. Successive
treatments for reducing suspended solids and fluorides are
shown.
Reduction of fluoride ion level to less than 10 mg/1 can be
accomplished through segregation and separate treatment of
fluoride-containing streams. This approach is already
planned by at least one producer, and is a good example of
in-process modification to reduce pollutant levels. A
modest reduction of fluoride of less than 50 percent is
presently achieved at only one facility with alum treatment
that has been installed for the purpose of flocculating
suspended solids.
Cost Variance
Age
The feldspar wet process subcategory consists of 6
facilities raiding in age from 3 to 26 years. Age is not a
significant cost variance factor because of similar raw
waste loads..
Location
179
-------
COST
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUB CATEGORY Feldspar, Wer Process
PLANT SIZE 90,900 METRIC TONS PER YEAR OF Feldspar
PLANT AGE 10 YEARS PLANT LOCATION Eastern U.S.
INVESTED CAPITAL COSTS-
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 6 M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/METRIC TON Feldspar
WASTE LOAD PARAMETERS
(kg /metric ton of ore )
Suspended Solids
Fluoride
pH
RAW
WASTE
LOAD
26fen
0.22-
0.95
—
LEVEL
A
(MIN)
115,000
18,700
107,500
2,000
128,200
1.41
0.6
0.2
6-9
B
260,000
42,100
132,500
2,000
176,600
1.95
0.3
0.1
6-9
C
375,000
60,800
157,500
2,000
220,300
2.42
0.3
0.03
6-9
D
185,000
30,100
118,500
4,000
152,600
1.68
0.3-3
0.2
6-9
E
415,000
70,800
156,500
6,000
233,300
2.56
0.1-0.3
0.03
6-9
LEVEL DESCRIPTION:
A — settling pond for suspended solids removal, no fluoride treatment.
B — larger settling ponds plus internal recycle of some fluoride-containing water plus
flocculation agents.
C — B plus segregation and separate lime treatment of Fluoride water.
D — present treatment by thickeners and filters plus lime treatment for fluoride.
E — D plus segregation and separate lime treatment of fluoride water plus improved
suspended solids treatment by clarifier installation.
-------
The feldspar wet processing operations are located in
southeastern and northeastern states in rural areas.
Location has not been found to be a significant cost
variance factor.
Size
The feldspar wet processing operations range in size from
45,700 to 154,000 kkg/yr (50,400-170,000 ton/yr). The
representative- facility is 90,900 kkg/yr (100,000 ton/yr).
The range of capital costs for treatment is $36,800 to
$250,000, and the range of annual operating costs is $18,400
to $165,000 as reported by the feldspar wet process
producers.
The variance of cost with size is estimated to be for
capital: exponent of 0.9 for treatments based on ponds,
exponent of 0.7 for treatments based on thickeners.
Operating costs other than taxes, insurance and capital
recovery are approximately proportional to size.
Cost Basis for Table 13
Capital Costs
Pond cost, $/hectare ($/acre): 30,600 (12,500)
Settling pond area, hectares (acres): 0.4-0.8 (1-2)
Thickeners, filters, clarifiers: 0-$50,000
Solids handling equipment: $40,000-50,000
Chemical metering equipment: 0-$50,000
Operating and Maintenance Costs
Other solid waste disposal costs: 0-$0.5/ton
Treatment chemicals: $10,000-25,000/yr
Energy unit cost: $0.01/kwh
Monitoring: 0-$15,000/yr
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KYANITE
Kyanite is produced at three locations. Two of the threa
facilities have complete recycle of process water after
passing through settling ponds. A summary of treatment-
technology costs is given in Table 14. Approximately
two-thirds of the cost comes from solid wastes removal from
the settling pond and land disposal. Depending on solid
waste load, costs could vary from approximately $1 to $4 per
metric ton of product.
Cost Variance
Age
The three facilities of this subcategory range in age
between 10 and 30 years. There is no significant treatment
cost variance due to this range.
Location
These facilities are in two southeastern states in rural
locations, not a significant cost variance factor.
Size
The sizes range from 16,000 to 45,000 kkg/yr (18,000 to
50,000 ton/yr). The costs given are meant to be
representative over this size range on a unit production
basis, that is, costs are roughly proportional to size.
Cost Basis for Kyanite Category
Capital Costs
Pond cost, S/hectare (S/acre): 12,300 (5,000)
Settling pond area, hectares (acres):10 (25)
Pipes: $28,000
Pumps: $4,400
Operating and Maintenance Costs
Pond dredging and solids waste hauling: $82,500/yr
Pond: $14,600/yr
Pipes: $3,300/yr
Energy unit cost: '10.01/kwh
Pumps: $1,200/yr
Labor: $3,000/yr
Maintenance: $16,900/yr
is:
-------
COST
SUBC ATEGORY Kyanite
PLANT SIZE 45,000
TABLE 14
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
PLANT AGE 15
METRIC TONS PER YEAR OF Kyanite
PLANT LOCATION Southeastern U.S.
INVESTED CAPITAL COSTS!
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 Q M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/ METRIC TON of Kyanite
WASTE LOAD PARAMETERS
(ka /metric ton of )
Tailings
TSS-
pH
RAW
WASTE
LOAD
5500
LEVEL
A
(MIN)
80,000
9,700
75,000
1,000
85,700
1.90
3
6-9
B
157,400
19,100
108,100
1,400
128,600
2.83
0
-
C
D
E
LEVEL DESCRIPTION:
A — pond settling
B — A plus recycle
Note: Most of the above cost at A level (65-70%) is the cost of removal and disposal
of solids from ponds.
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iMAGNESITE
There is only one known U.S. facility that produces magnesia
from naturally occurring magnesite ore. This facility is
located in a dry western climate and has no discharge to
surface water by virtue of a combination
evaporation-percolation pond. Capital costs for this
treatment are $300,000 with operation/maintenance costs of
$15,000/yr plus annual capital investment costs of $35,220.
SHALE AND COMMON CLAY
No water is used in either mining or processing of shale and
common clay. The only water involved is occasional mine
drainage from rain or ground water. In most cases runoff
does not pick up significant suspended solids. Any needed
treatment costs would be expected to fall in the range of
$0.01 to $0.05/kkg shale produced.
Cost Variance
Age
Shale facilities range from 8 to 80 years in age. This is
not a significant variance factor for the costs to treat
mine water since the eqiupment is similar.
Location
Shale facilities having significant mine water are located
through the eastern half of the U.S. The volume of mine
water is the only significant cost factor influenced by
location.
Size
Shale facilities range from 700 to 250,000 kkg/yr (770 to
270,000 ton/yr). Size is not a cost variance factor, since
the mine pumpout is unrelated to production rate.
APLITE
Aplite is dry mined produced at two facilities in the U.S.
One facility with a dry process uses wet scrubbers the
discharge from which is ponded to remove suspended solids
and then discharged. Waste water treatment costs were
calculated to be $0.4S/kkg product. The second processing
facility uses a wet classification process and a
significantly higher water usage per ton of product than the
first facility. Except for a pond pumpout every one to two
years, this facility is on complete recycle. The total
treatment costs per kkg of product is $0.78. The estimated
costs to bring the "dry process" facility to a condition of
total recycle of its scrubber water are:
184
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capital: $9,000
annual capital recovery:$1,<*70
annual operating and maintenance, excluding power and
energy: $630
annual power and energy: $1,300
total annual cost:$3,400
Cost Variance
Age
Aplite is produced by two facilities which are 17 and 41
years old. Age has not been found to be a significant cost
variance factor.
Location
Both aplite facilities are located in Virginia and,
therefore, location is not a significant cost variance
factor.
Size
The aplite facilities are 54,400 kkg/yr (60,000 ton/yr) and
136,000 kkg/yr (150,000 ton/yr). The costs per unit
production are applicable for only the facilities specified.
Cost Basis for Aplite category
Capital Costs
Pond cost, $/hectare ($/acre): 12,300-24,500
(5,000-10,000)
Settling pond area, hectares (acres): 5.5-32 (14-80)
Recycle equipment: $9,000
Operating and Maintenance Costs
Treatment chemical costs: $3,500/yr
Energy unit cost: $0.01/kwh
Recycle Q & M cost: $1,900/yr
Maintenance:$4,500-16» 500/yr
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TALC MINERALS GROUP
Suspended solids are the only major pollutant involved in
the waste water from this category. In some wet processing
operations pH control through addition of acid and alkalies
is practiced. Neutralization of the final waste water may
be needed to bring the pH into the 6-9 range. Both mines
and processing facilities may be either wet or dry. Dry
operations have no treatment costs.
Mine Water
Rain water and ground water seepage often make it necessary
to pumpout mine water. The only treatment normally needed
for this water is settling ponds for suspended solids.
Ponds are usually small, one acre or less, costs for this
treatment are in the range of $0.01 to 200 kkg talc
produced, the large figure representing small mines.
Wet Processes
Wet processes are conducted in both the eastern and western
U.S.
Eastern Operations
Waste water from wet processes comes from process operations
and/or scrubber water. The usual method of treating the
effluent is to adjust pH by addition of lime, followed by
pond settling.
Treatment options, costs and resultant effluent quality are
summarized in Table 15. Facilities not requiring lime
treatment would have somewhat lower costs than those given.
Western Operations
Wet process facilities in the western part of the U.S. are
mostly located in arid regions and can achieve no discharge
through evaporation. costs for these evaporation pond
systems were estimated to be the same cost as Level B of
Table 15. The required evaporation pond size in this case
is similar to that needed for good settling pond
performance.
Cost Variance
Age
Facilities in the talc minerals group range from 2 to 70
years of age. However, the heavy media separation and
flotation subcategory with a discharge consists of only
186
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COST
TABLE 15
FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUBCATEGORY Talc Minerals, Ore Mining, Heavy Madia and Flotation
PLANT SIZE 45,000
PLANT AGE 25 YEARS
METRIC TONS PER YEAR OF talc minerals
PLANT LOCATION Eastern U.S.
INVESTED CAPITAL COSTS'.
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 & M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/METRIC TON of products
WASTE LOAD PARAMETERS
(kg /metric ton of products )
TSS
pH
RAW
WASTE
LOAD
800 to
1800
LEVEL
A
(MIN)
100,000
11,700
27,000
2,000
40,700
0.89
0.3-1.3
6-9
B
150,000
17,600
34,000
3,000
54,600
1.09
0.3
6-9
C
D
E
LEVEL DESCRIPTION:
A — lime treatment and pond settling
B — A plus additional pond settling
187
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three facilities of 10 to 30 years of age. This is not a
significant treatment cost variance factor.
Location
The heavy media separation and flotation subcategory
facilities are located in rural areas of the eastern U.S.
This location spread is a minor cost variance factor.
Size
Talc minerals facilities range in size from 12,000 to
300,000 kkg/yr (13,000 to 330,000 ton/yr). The heavy media
separation and flotation subcategory facilities range from
12,000 to 236,000 kkg/yr (13,000 to 260,000 ton/yr). The
representative facility size selected is 45,000 kkg/yr
(50,000 ton/yr). Over this range of sizes, capital costs
variance can be estimated by an exponent of 0.8 to size, and
operating costs other than capital recovery, taxes and
insurance are approximately proportional to size.
Cost Basis for Table 15.
Capital Costs
Land cost, $/hectare ($/acre): 24,500 (10,000)
Mine pumpout, settling pond area, hectares (acres):
up to 0.4 (up to 1)
Process settling pond area, hectares (acres): 2 (5)
Pumps and pipes: $15,000
Chemical treatment equipment: $35,000
Operating and Maintenance costs
Treatment chemicals
Lime: $22/kkg ($20/ton)
Energy cost: $1,000-2,000/yr
Maintenance: $5,000/yr
Labor: $3,000-10,000/yr
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GARNET
There are three garnet producers in the U.S., two in Idaho
and one in New York State. Two basic types of processing
are used: (1) wet washing and classifying of the ore, and
(2) heavy media and froth flotation. Washing and
classifying facilities have already incurred estimated waste
water treatment costs of $0.16 per metric ton of garnet
produced. Heavy media and flotation process waste water
treatment estimated costs already incurred are significantly
higher, $5 to $10/kkg of product.
The quantity and quality of discharge at the Idaho
facilities are not known by the manufacturer. Sampling was
precluded by seasonal halting of operations. The hydraulic
load per ton of product at the Idaho operations is believed
to be higher than at the New York operation studied. The
costs to reduce the amount of suspended solids in these
discharges to that of the New York operation are estimated
to be:
capital: $100,000
annual operating costs: $30,000
Cost Variance
Age
There are three garnet producers ranging in age from 10 to
50 years. Age has not been found to be a significant cost
variance factor.
Location
Two of the garnet producers are located in Idaho and one in
New York State. The regional deposits differ widely making
different ore processes necessary. Due to this difference
in processes, there is no representative facility in this
subcategory. Treatment costs must be calculated on an
individual basis.
Size
The garnet producers range in size from 5,100 kkg/yr to an
estimated 86,200 kkg/yr (5,600 ton/yr to an estimated
95,000 ton/yr). The differences in size are so great that
there is no representative facility for this subcategory.
Due to process and size differences, treatment costs must be
calculated on an individual basis.
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TRIPOLI
There are several tripoli producers in the United States.
The production is dry both at the facilities and the mines.
One small facility has installed a wet scrubber.
Cost Variance
There is only one facility in this subcategory that has any
process waste water. This is only from a special process
producing 10 percent of that facility's production.
Therefore, there are no cost variances due to age, location
or size.
DIATOMITE
Diatomite is mined and processed in the western U.S. Both
mining and processing are practically dry operations.
Evaporation ponds are used for waste disposal in all cases.
The selected technology of partial recycle and chemical
treatment is practiced at the better facilities. All
facilities are currently employing settling and neutra-
lization.
GRAPHITE
There is only one producer of natural graphite in the United
States. For this mine and processing facility, mine
drainage, settling pond seepage and process water are
treated for suspended solids, iron removal and pH level.
The pH level and iron precipitation are controlled by lime
addition. The precipitated iron and other suspended solids
are removed in the settling pond and the treated waste water
discharged. Present treatment costs are approximately $20-
25/kkg graphite produced.
JADE
The jade industry is very small and involves very little
waste water. One facility representing 55 percent of the
total U.S. production has only 190 I/day (50 gpd) of waste
water. Suspended solids are settled in a small tank
followed by discharge to the company lawn. Treatment costs
are considered negligible.
NOVACULITE
There is only one novaculite producer in the United States.
Processing is a dry operation resulting in no discharge. A
dust scrubber is utilized and the water is recycled after
passing through a settling tank. Both present treatment
costs and proposed recycle costs are negligible.
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SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH THE
APPLICATION OF THE
BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE
INTRODUCTION
The effluent limitations which must be achieved by July I,
1977, are based on the degree of effluent reduction
attainable through the application of the best practicable
control technology currently available. For the mining of
clay, ceramic, refractory, and miscellaneous materials, this
level of technology was based on the average of the best
existing performance by facilities of various sizes, ages,
and processes within each of the industry's subcategories.
In Section IV, this segment of the minerals mining and
processing industry was divided into 17 major categories
based on similarities of process. Several of these major
categories have been further subcategorized and, for reasons
explained in Section IV, each subcategory will be treated
separately for the recommendation of effluent limitations
guidelines and standards of performance.
Best practicable control technology currently available
emphasizes treatment facilities at the end of a
manufacturing process but also includes the control
technology within the process itself when it is considered
to be normal practice within an industry. Examples of waste
management techniques which were considered normal practice
within these industries are:
a) manufacturing process controls;
b) recycle and alternative uses of water; and
c) recovery and/or resue of some waste water constitutents.
Consideration was also given to:
a) the total cost of application of technology in relation
to the effluent reduction benefits to be achieved from
such application;
b) the size and age of equipment and facilities involved;
c) the process employed;
d) the engineering aspects of the application of various
types of control techniques;
e) process changes; and
f) non-water quality environmental impact (including energy
requirements).
191
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The following is a discussion of the best practicable
control technology currently available for each of the
chemical subcategories, and the proposed limitations on the
pollutants in their effluents.
GENERAL WATER GUIDELINES
process Water
process water is defined as any water contacting the ore,
processing chemicals, intermediate products, by-products or
products of a process including contact cooling water. All
process water effluents are limited to the pH range of 6.0
to 9.0 unless otherwise specified.
Process generated waste water is defined as any water which
in the mineral processing operations such as crushing,
washing and beneficiation, comes into direct contact with
any raw material, intermediate product, by-product or
product used in or resulting from the process.
Where sufficient data was available a statistical analysis
of the data was performed to determine a monthly and a daily
maximum. In most subcategories, where there is an allowable
discharge, an achievable monthly maximum was determined from
the data available.
A detailed analysis of the ratio of daily TSS to monthly TSS
maximum at a 99 percent level of confidence for large
phosphate slime ponds indicate that a TSS ratio of 2.0 is
representative of a large settling pond treatment system,
and this ratio was used where there was insufficient data to
predict a daily maximum directly.
A ratio of 2.0 was also used for parameters other than TSS.
It is judged that this is an adequate ratio since the
•treatment systems for F, Zn and Fe for instance, have
controllable variables, such as pH and amount of lime
addition. This is in contrast to a pond treating only TSS
which has few if any operator controllable variables.
Cooling Water
In the minerals mining and processing industry, cooling and
process waters are sometimes mixed prior to treatment and
discharge. In other situtations, cooling water is
discharged separately. Based on the application of best
practicable technology currently available, the
recommendations for the discharge of such cooling water are
as follows.
192
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An allowed discharge of all non-contact cooling waters
provided that the following conditions are met:
(a) Thermal pollution be in accordance with EPA standards.
Excessive thermal rise in once through non-contact
cooling water in the mineral mining industry has not
been a significant problem.
(b) All non-contact cooling waters should be monitored to
detect leaks of pollutants from the process. Provisions
should be made for treatment to the standards
established for process waste water discharges prior to
release in the event of such leaks.
(c) No untreated process waters be added to the cooling
waters prior to discharge.
The above non-contact cooling water recommendations should
be considered as interim, since this type of water plus
blowdowns from water treatment, boilers and cooling towers
will be regulated by EPA as a separate category.
Mine Drainage
Mine drainage is any water drained, pumped or siphoned from
a mine.
Storm Water Runoff
Untreated overflow may be discharged from process waste
water or mine drainage impoundments without limitation if
the impoundments are designed, constructed and operated to
contain all process generated waste water or mine drainage
and surface runoff into the impoundments resulting from a 10
year 2*4 hour precipitation event as established by the
National Climatic Center, National Oceanic and Atmospheric
Administration for the locality in which such impoundments
are located. To preclude unfavorable water balance
conditions resulting from precipitation and runoff in
connection with tailing impoundments, diversion ditching
should be constructed to prevent natural drainage or runoff
from mingling with process waste water or mine drainage.
193
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PROCESS WASTE WATER GUIDELINES AND LIMITATIONS
BENTONITE
There is no control technology needed for the processing of
bentonite, because no water is used in the process. Hence
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Ef fluent_L.imitation
Characteristic
TSS 35 mg/1
FIRE CLAY
The best practicable control technology currently available
is no discharge of process generated waste water pollutants
since no process water is used.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Eff j.uent_LimitatiOQ
Characteristic Daily_Maximum
TSS 35 mg/1
FULLER'S EARTH - ATTAPULGITE
Based upon the information contained in Sections ill through
VIII, a determination has been made that the degree o,f
effluent reduction attainable through the application of the
best practicable control technology currently available is:
no discharge of process generated waste water pollutants.
This condition is currently met by four facilities.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Ef fluent_Lijnitation
Characteristic Daiiy__Maximum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of Fuller's Earth (attapulgite) is
no discharge of process waste water. This is currently
achieved by four facilities. To implement this technology
194
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at facilities not already using the recommended control
techniques would require use of dry air pollution control
equipment and reuse of waste fines or recycle of fines
slurry and scrubber water after settling and pH adjustment.
FULLER'S EARTH - MONTMORILLONITE
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
Best practicable control technology currently available for
the mining and processing of Fuller's Earth-Montmorillonite
is recycle of all process scrubber water. To implement this
technology at facilities not already using the recommended
control techniques would require the installation of pumps
and associated recycle equipment. Two of the three
facilities studied presently use the recommended technology.
KAOLIN - DRY PROCESSING
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
This is feasible since no process waste water is used.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Ef fj.uent Ef_f_luent_Limitation
Characteristic DaiiY_Maximum
TSS 35 mg/1
KAOLIN MINING - WET PROCESSING
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is:
Effluent .Limitation
£ Monthly Average Daily Maximum
TSS, mg/1 U5 90
Turbidity, JTU or FTU 50 100
Zinc, mg/1 0.25 0.50
195
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The above limitations were based on the performance
attainable by the two facilities (3024 and 3025), see
Section V. In addition other Georgia kaolin producers have
claimed that these limits are achievable.
From the data in Section V the following limits apply to
mine drainage from mines not pumping the ore as a slurry to
the processing facility and process contaminated runoff.
Effluent Eff lu§nt_L.imitatign
Characteristic Daily Maximum
TSS 35 mg/1
From the data in Section V the following limits apply to
mine dewatering from mines pumping the ore as a slurry to
the processing facility.
Effly§nt_Limitatign
Eff_luent_Characteristic M°nthlY_Ayerage 5.§iiY._Maximuffl
TSS, mg/1 45 90
Turbidity, JTU or FTU 50 100
The use of clay dispersants in the slurry necessitates the
use of flocculants and clarification in larger ponds than
would be needed if the ore were transported by dry means.
Best practicable control technology currently available for
the wet mining and processing of kaolin for high grade
product is lime treatment to precipitate zinc followed by
pond settling to reduce suspended solids. To implement this
technology at facilities not already using the recommended
control techniques would require the installation of lime
treatment facilities and settling ponds.
The recommended technologies are presently being used by at
least 4 facilities.
BALL CLAY - WET PROCESSING
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is:
Effluent_Limitatign
Eff luent_Char act eristic Monthly__Ayerage DailY_Maximum
TSS 0.17 0.34
196
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The above limitations were based on the performance
demonstrated at facility 5689 which employs wet scrubbers
for dust collection. Other facilities have no wet scrubbers
and hence no process waste water.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluejit Effluent Limitation
Characteristic Daily Maximum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of ball clay is either the use of
dry bag collection techniques for dust control or, where wet
scrubbers are employed, the use of settling ponds to reduce
suspended solids in the effluent. To implement this
technology at facilities not already using the recommended
control techniques would require either the installation of
dry bag collectors or settling ponds. All of the facilities
contacted use either one or the other of the recommended
technologies.
BALL CLAY-DRY PROCESSING
Where ball clay is processed without the use of wet
scrubbers for air emissions control there is no need to
discharge process waste water since it is either evaporated
or goes to the product. Hence, best practicable control
technology currently available is no discharge of process
generated waste water pollutants.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent,Limitation
Characteristic Daily,Maximum
TSS 35 mg/1
FELDSPAR - FLOTATION
Based upon the information contained in Sections ill through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is:
Effluent_Limitation
kg/kkg_j[lb/10^0~lbl._gf_ore
Eff luent Characteristic Monthly__ Aver age Da ily_ Maximum
197
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TSS 0.60 1.2
Fluoride 0.175 0.35
The above limitations were based on the performance achieved
by three exemplary facilities for TSS (3026, 305U and 3067)
and one of these three (3026) for fluoride reduction. The
fluoride can be achieved by treatment with lime of the HF
flotation process waste water only to 40 mg/1. This waste
stream can then be combined with the remaining 75 percent of
the non-HF contaminated water.
From the data in Section V the following limits for mine
drainage are achievable.
Ef^luent_i,ig\itation
Daily Maximum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of feldspar by the wet process is
to recycle part of the process waste water for washing
purposes, then neutralize and settle the remaining waste
water to reduce the suspended solids. In addition, fluoride
reduction can be accomplished by chemical treatment of waste
water from the flotation circuit and/or partial recycle of
the fluoride containing portion of the flotation circuit.
To implement this technology at facilities not already using
the recommended control techniques would reguire
installation of piping and pumps for recycle of water and
installation of neutralization, chemical treatment and
settling equipment or ponds. The selected technology of
partial recycle and chemical treatment is practiced at the
better facilities. All facilities are currently employing
settling and neutralization.
FELDSPAR-NON-FLOTATION
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
This technology for the processing of feldspar by the dry
process is natural evaporation of dust control water used in
the process. This is the only water used in the process.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent Limitation
Characteristic Daily_Maximum
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TSS 35 mg/1
KYANITE
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent Limitation
Characteristic DaiiY_Maximum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of kyanite by the standard process
is recycle of process water from settling ponds. To
implement this technology at facilities not already using
the recommended control techniques would require
installation of suitable impoundments and recycle where
required.
One of the three facilities in this production subcategory
is currently employing the recommended technologies.
MAGNESITE
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
Best practicable control technology currently available for
the manufacture of magnesia (MgO) from naturally occurring
magnesite is either impoundment or recycle of process waste
water. There is one facility in the U.S. and this facility
currently uses the recommended technology.
SHALE AND COMMON CLAY
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants,
since no water is used.
199
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From the data in section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent, Limitation
Characteristic Daily Max imum
TSS 35 mg/1
APLITE
Based upon the information contained in Sections III through
VIII , a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Characteristic D a i ly Max im urn
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of aplite is ponding of process
waste water to settle solids and recycle of water. To
implement this technology at facilities not already using
the recommended control techniques would require
installation of water recycle equipment.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE, DRY PROCESS
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants
because no process water is used.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE, WASHING PROCESS
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
Best practicable control technology currently available for
the mining of talc minerals by the ore mining and washing
processes is total impoundment or recycle of process waste
water. All facilities in this production subcategory
currently employ the recommended control technology.
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TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE, HEAVY MEDIA
AND FLOTATION
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is:
Ef fluent _ Limit at ion
Ef f_luent_Characteristic Monthly._Average Daily_Maximum
TSS 0.5 1.0
The above limitations were based on the performance
achievable by three facilities (2032, 2033 and 2044) and a
fourth facility (2031) achieving no discharge of process
waste water.
Best, practicable control technology currently available for
the processing of talc minerals by heavy media process is pH
adjustment of the flotation tailings, gravity settling and
clarification. To implement this technology at facilities
not already using the recommended control techniques would
require the installation of pH monitoring and adjustment
equipment and the installation of settling and/or
clarification ponds. All facilities in this subcategory are
presently using the recommended technologies.
TALC, STEATITE, SOAPSTONE, PYROPHYYLLITE, MINE DRAINAGE
AND PROCESS CONTAMINATED RUNOFF
Based upon information contained in section V, a
determination has been made that the degree of effluent
attainble through the application of the best practicable
control technology currently available is:
Ef f lueQt_Limitation
paily__Maximum
TSS 30 mg/1
The above limitations are based on the effluent quality from
7 mines.
GARNET
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent attainable through the application of the best
practicable control technology currently available is:
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EfflufQt Limitation
kg/!slsg_ilb/iQOOlibL
Efflugnt^Charactgristic isn^ElY-Ayerage
TSS 0.4 0.8
The above limitations were based on an estimated average
process waste water discharge of 12,500 1/kkg
(3,000 gal/ton) product and an estimated TSS level of
30 mg/1. In the two facilities studied, mine water is used
as process water.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent Lj.mj.tatj.on
mum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of garnet is pH adjustment, where
necessary, and settling of suspended solids. To implement
this technology at facilities not already using the
recommended control techniques would require the
installation of pH adjustment equipment, where necessary,
and construction of settling ponds. The two facilities
accounting for over 80 percent of the U.S. production are
presently using the recommended technologies.
TRIPOLI
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants
from dry processes, since no process waste water is used.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Ef iuent_Limitati2D
Characteristic
TSS 35 mg/1
DIATOMITE
Based upon the information contained in Sections III through
VIII , a determination has been made that the degree of
effluent reduction attainable through the application of the
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best practicable control technology currently available is
no discharge of process generated waste water pollutants.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent Limitation
Characteristic Daily Maximum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of diatomite by the standard
process is use of evaporation ponds and/or recycle of
process water. To implement this technology at facilities
not already using the recommended control techniques would
require the construction of impoundments and/or recycling
equipment. Three facilities (5501, 5505 and 5500) of this
subcategory representing approximately half the U.S.
production utilize this recommended technology.
GRAPHITE
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is:
Effluent ^Limitation
mg/1
EffluentCharacterstic
TSS 10 20
Total Iron 1 2
The above average limitations were based on the performance
achievable by the single facility in this subcategory. Both
process waste water and mine drainage are included.
Concentration was used because of the variable flow of mine
seepage.
Best practicable control technology currently available for
the mining and processing of graphite is neutralization of
mine seepage and pond settling. There is only one facility
in the U.S., and this facility currently uses the
recommended technology.
JADE
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Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
From the data in section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent Limitation
Characteristic Daily_Maximum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of jade is settling and
evaporation of the small volume of waste water. To
implement this technology at facilities not already using
the recommended control techniques would require
installation of a settling tank and appropriate evaporation
facilities. The only major U.S. jade production facility
presently employs these techniques.
NOVACULITE
Based upon the information contained in Sections III through
VIII, a determination has been made that the degree of
effluent reduction attainable through the application of the
best practicable control technology currently available is
no discharge of process generated waste water pollutants.
From the data in Section V the following limits for mine
drainage and process contaminated runoff are achievable.
Effluent Effluent_Limitation
QhSESStSEiStic Daily Maximum
TSS 35 mg/1
Best practicable control technology currently available for
the mining and processing of novaculite by the quarrying
process is total recycle of process scrubber water. There
is only one facility in the U.S. It is presently using this
technology.
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SECTION X
EFFLUENT REDUCTION ATTAINABLE THROUGH THE
APPLICATION OF THE BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE
INTRODUCTION
The effluent limitations which must be achieved by July 1,
1983 are based on the degree of effluent reduction attain-
able through the application of the best available
technology economically achievable. For the mining clay,
ceramic, refractory and miscellaneous minerals industry,
this level of technology was based on the very best control
and treatment technology employed by a specific point source
within each of the industry's subcategories, or where it is
readily transferable from one industry process to another.
In Section IV, this segment of the mineral mining and
processing industry was divided into 17 major categories
based on similarities of process. Several of those major
categories have been further subcategorized and, for reasons
explained in Section IV, each subcategory will be treated
separately for the recommendation of effluent limitations
guidelines and standards of performance.
The following factors were taken into consideration in
determining the best available technology economically
achievable:
(1) the age of equipment and facilities involved;
(2) the process employed;
(3) the engineering aspects of the application of various
types of control techniques;
(4) process changes;
(5) cost of achieving the effluent reduction resulting from
application of BATEA; and
(6) non-water quality environmental impact (including energy
requirements).
In contrast to the best practicable technology currently
available, best available technology economically achievable
assesses the availability in all cases of in-process
controls as well as control or additional treatment
techniques employed at the end of a production process.
In-process control options available which were considered
in establishing these control and treatment technologies
include the following:
(1) alternative water uses
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(2) water conservation
(3) waste stream segregation
(U) water reuse
(5) cascading water uses
(6) by-product recovery
(7) reuse of waste water constituents
(8) waste treatment
(9) good housekeeping
(tO) preventive maintenance
(11) quality control (raw material, product, effluent)
(12) monitoring and alarm systems.
Those facility processes and control technologies which at
the pilot facility, semi-works, or other level, have
demonstrated both technological performances and economic
viability at a level sufficient to reasonably justify
investing in such facilities were also considered in
assessing the best available technology economically
achievable. Although economic factors are considered in
this development, the costs for this level of control are
intended to be for the top-of-the-line of current technology
subject to limitations imposed by economic and engineering
feasibility. However, this technology may necessitate some
industrially sponsored development work prior to its
application.
Based upon the information contained in Sections III through
IX of this report, the following determinations were made on
the degree of effluent reduction attainable with the appli-
cation of the best available control technology economically
achievable in the various subcategories of the inorganic
chemical industry.
GENERAL WATER GUIDELINES
Storm Water Runoff
Untreated overflow may be discharged from process waste
water or mine drainage impoundments without limitation if
the impoundments are designed, constructed and operated to
contain all process generated waste water or mine drainage
and surface runoff into the impoundments resulting from a 25
year 24 hour precipitation event as established by the
National Climatic Center, National Oceanic and Atmospheric
Administration for the locality in which such impoundments
are located. To preclude unfavorable water balance
conditions resulting from precipitation and runoff in
connection with tailing impoundments, diversion ditching
should be constructed to prevent natural drainage or runoff
from mingling with process waste water or mine drainage.
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PROCESS WASTEWATER GUIDELINES AND LIMITATIONS
NO DISCHARGE GROUP
The following industry subcategories are required to achieve
no discharge of process generated waste water pollutants to
navigable waters based on best practicable control
technology currently available:
bentonite
fire clay
fuller's earth (montmorillonite and attapulgite)
kaolin (general purpose grade)
ball clay (dry process)
feldspar (non-flotation)
kyanite
magnesite
shale
aplite
talc group (dry process)
talc group (washing process)
tripoli
diatomite
jade
novaculite
Best available technology economically achievable is also no
discharge of process waste water pollutants for these
subcategories.
KAOLIN - WET PROCESSING
Based upon the information contained in Sections III through
IX, a determination has been made that the deqree of
effluent reduction attainable through the application of the
best available technology economically achievable is the
same as for the best practicable control technology
currently available.
Best available technology economically achievable for the
mining and processing of ball clay is the use of dry bag
collectors where possible or recycle of wet scrubber where
wet scrubbers are used. To implement this technology at
facilities not already using the recommended control
techniques would require the installation of settling ponds
or equipment and flocculation plus piping and pumps for
recycle of scrubber water where used. Settling of suspended
solids and recycle of scrubber water is currently practiced
in other portions of this industry.
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FELDSPAR - - FLOTATION
Based upon the information contained in Sections III through
IX, a determination has been made that the degree of
effluent reduction attainable through the application of the
best available technology economically achievable is:
EffluentLimitation
Effluent &2Zfcki_Jlb/1000_lb£_gr e_ grocessed
Characteristic M.2D.^illY_Ay.§r.ii9§ Qaily_ Maximum
TSS 0.6 1.2
Fluoride 0.13 0.26
The above limitation for fluoride is based on an improvement
in exemplary facility performance by lime treatment to
reduce fluorides to 30 mg/1 in the HF contaminated
segregated waste water. The limitation on suspended solids
for best practicable control technology currently available
is deemed also to represent best available technology
economically achievable.
Best available technology economically achievable for the
mining and processing of feldspar by the wet process is to
recycle part of the process waste water for washing
purposes, neutralization to pH 9 with lime to reduce soluble
fluoride and settling to remove suspended solids. To
implement this technology at facilities not already using
the recommended control techniques would require
installation of piping and pumps for recycle of water, lime
feeding and neutralization equipment and settling equipment
or ponds. The selected technology of partial recycle is
currently practiced at two facilities. Three facilities are
currently using lime treatment to adjust pH and can readily
adopt this technology to reduce soluble fluoride. All
facilities are using settling equipment or ponds.
TALC MINERALS GROUP, HEAVY MEDIA AND FLOTATION
Based upon the information contained in sections III through
IX, a determination has been made that the degree of
effluent reduction attainable through the application of the
best available technology economically achievable is:
Effluent Limitation
iifiyent kg/k&3_!lb/1000_lbj_
Characteristic Monthly._Ayerage Dai ly_ axjmuin
TSS 0.3 0.6
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The above limitations were based on performance of one
facility (2032) plus one facility achieving no discharge of
process water (2031) .
Best available technology economically achievable for the
mining and processing of talc minerals by the ore mining,
heavy media and/or flotation process is the same as for best
practicable control technology currently available plus
additional settling or in one case, conversion from wet
scrubbing to a dry collection method to control air
pollution. To implement this technology at facilities not
already using the recommended control techniques would
require installation of additional ponds or installation of
dry dust collectors. Two of the four facilities in this
subcategory are presently achieving this level of effluent
reduction using the recommended treatment technologies.
GARNET
Based upon the information contained in Sections III through
IX, a determination has been made that the degree of
effluent reduction attainable through the application of the
best available technology economically achievable is:
Ef flu§nt_Limitatign
Effluent kq/kkq j[lb/1000_lb) product
Mgnthly._Ave_rage Daily_ Maximum
TSS 0.25 0.5
The above limitations were based on an estimated average
process waste water discharge of 12,500 1/kkg (3,000
gal/ton) and an estimated TSS level of 20 mg/1.
Best available technology economically achievable for the
mining and processing of garnet is pH adjustment to achieve
pH 6 to 9, settling of suspended solids, and sand bed
filtration where necessary. To implement this technology at
facilities not already using the recommended control
techniques would require the installation of pH
neutralization equipment, settling ponds, and sand bed
filter equipment.
Two facilities accounting for over 80 percent of the U.S.
production presently use a portion of the recommended
technologies and technology exists for further removal of
suspended solids.
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GRAPHITE
Based upon the information contained in Sections III through
IX, a determination has been made that the degree of
effluent reduction attainable through the application of the
best available technology economically achievable is the
same as that recommended for best practicable control
technology currently available because no proven technology
option exists to reduce the pollutants further.
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SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
AND PRETREATMENT STANDARDS
INTRODUCTION
This level of technology is to be achieved by new sources.
The term "new source" is defined in the Act to mean "any
source, the construction of which is commenced after the
publication of proposed regulations prescribing a standard
of performance". This technology is evaluated by adding to
the consideration underlying the identification of best
available technology economically achievable, a
determination of what higher levels of pollution control are
available through the use of improved production processes
and/or treatment techniques. Thus, in addition to
considering the best in-facility and end-of-process control
technology, new source performance standards are how the
level of effluent may be reduced by changing the production
process itself. Alternative processes, operating methods or
other alternatives were considered. However, the end result
of the analysis identifies effluent standards which reflect
levels of control achievable through the use of improved
production processes (as well as control technology), rather
than prescribing a particular type of process or technology
which must be employed.
The following factors were considered with respect to
production processes which were analyzed in assessing the
best demonstrated control technology currently available for
new sources:
a) the type of process employed and process changes;
b) operating methods;
c) batch as opposed to continuous operations;
d) use of alternative raw materials and mixes of raw
materials;
e) use of dry rather than wet processes (including
substitution of recoverable solvents from water); and
f) recovery of pollutants as by-products.
In addition to the effluent limitations covering discharges
directly into waterways, the constituents of the effluent
discharge from a facility within the industrial category
which would interfere with, pass through, or otherwise be
incompatible with a well designed and operated publicly
owned activated sludge or trickling filter waste water
treatment facility were identified. A determination was
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made of whether the introduction of such pollutants into the
treatment facility should be completely prohibited.
GENERAL WATER GUIDELINES
The process water, cooling water and blowdown guidelines for
new sources are identical to those based on best available
technology economically achievable.
PROCESS WATER GUIDELINES
Based upon the information contained in Sections III through
X of this report, the following determinations were made on
the degree of effluent reduction attainable with the
application of new source standards for the various
subcategories of -the clay, ceramic, refractory, and
miscellaneous minerals segment of the mineral mining and
processing industry.
Storm Water Runoff
Untreated overflow may be discharged from process waste
water or mine drainage impoundments without limitation if
the impoundments are designed, constructed and operated to
contain all process generated waste water or mine drainage
and surface runoff into the impoundments resulting from a 25
year 24 hour precipitation event as established by the
National Climatic Center, National Oceanic and Atmospheric
Administration for the locality in which such impoundments
are located. To preclude unfavorable water balance
conditions resulting from precipitation and runoff in
connection with tailing impoundments, diversion ditching
should be constructed to prevent natural drainage or runoff
from mingling with process waste water or mine drainage.
The following industry subcategories were required to
achieve no discharge of process generated waste water
pollutants to navigable waters based on best available
technology economically achievable:
bentonite
fire clay
fuller's earth (montmorillonite and attapulgite)
kaolin (dry process)
ball clay
feldspar (non-flotation)
kyanite
magnesite
shale
aplite
talc group (dry process)
talc group (ore mining and washing process)
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tripoli
diatomite
jade
novaculite
The same limitations guidelines are recommended as new
source performance standards.
The following industry subcategories are required to achieve
specific effluent limitations as given in the following
paragraphs.
KAOLIN (WET PROCESS)
Same as best available technology economically achievable.
FELDSPAR (FLOTATION)
Same as best available technology economically achievable.
TALC GROUP (HEAVY MEDIA AND FLOATION PROCESS)
Same as best available technology economically achievable
GARNET
Same as best available -technology economically achievable
GRAPHITE
Same as best available technology economically achievable
PRETREATMENT STANDARDS
Recommended pretreatment guidelines for discharge of
facility waste water into public treatment works conform in
general with EPA Pretreatment Standards for Municipal Sewer
Works as published in the July 19, 1973 Federal Register and
"Title 40 - Protection of the Environment, Chapter 1
Environmental Protection Agency, Subchapter D - Water
Programs - Part 128 - Pretreatment Standards" a subsequent
EPA publication. The following definitions conform to these
publications:
Compatible Pollutant
The term "compatible pollutant" means biochemical oxygen
demand, suspended solids, pH and fecal coliform bacteria,
plus additional pollutants identified in the NPDES permit if
the publicly owned treatment works was designed to treat
such pollutants, and, in fact, does remove such pollutants
213
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to a substantial degree. Examples of such additional
pollutants may include:
chemical oxygen demand
total organic carbon
phosphorus and phosphorus compounds
nitrogen and nitrogen compounds
fats, oils, and greases of animal or vegetable
origin except as defined below in
Prohibited Wastes.
Incompatible Pollutant
The term "incompatible pollutant" means any pollutant which
is not a compatible pollutant as defined above.
Joint Treatment Works
Publicly owned treatment works for both non-industrial and
industrial waste water.
Major Contributing Industry
A major contributing industry is an industrial user of the
publicly owned treatment works if it: has a flow of 50,000
gallons or more per average work day; has a flow greater
than five percent of the flow carried by the municipal
system receiving the waste; has in its waste, a toxic
pollutant in toxic amounts as defined in standards issued
under Section 307 (a) of the Act; or is found by the permit
issuance authority, in connection with the issuance of an
NPDES permit to the publicly owned treatment works receiving
the waste, to have significant impact, either singly or in
combination with other contributing industries, on that
treatment works or upon the quality of effluent from that
treatment works.
Pretreatment
Treatment of waste waters from sources before introduction
into the joint treatment works.
Prohibited Wastes
No waste introduced into a publicly owned treatment works
shall interfere with the operation or performance of the
works. Specifically, the following wastes shall not be
introduced into the publicly owned treatment works:
a. Wastes which create a fire or explosion hazard in the
publicly owned treatment works;
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b. Wastes which will cause corrosive structural damage to
treatment works, but in no case wastes with a pH lower
than 5.0, unless the works are designed to accommodate
such wastes;
c. Solid or viscous wastes in amounts which would cause
obstruction to the flow in sewers, or other interference
with the proper operation of the publicly owned
treatment works, and
d. Wastes at a flow rate and/or pollutant discharge rate
which is excessive over relatively short time periods so
that there is a treatment process upset and subsequent
loss of treatment efficiency.
Recommended Pretreatment Guidelines for Existing Sources
In accordance with the preceding Pretreatment Standards for
Municipal Sewer Works, the following are recommended for
Pretreatment Guidelines for the waste water effluents:
a. No pretreatment required for removal of compatible
pollutants - biochemical oxygen demand, suspended solids
(unless hazardous) pH and fecal coliform bacteria. The
principal pollutant in the mineral industry is suspended
solids.
b. Suspended solids containing hazardous pollutants such as
heavy metals, cyanides and chromates should be
restricted to those quantities recommended for the best
practicable control technology currently available for
existing sources and new source performance standards
for new sources.
c. Pollutants such as chemical oxygen demand, total organic
carbon, phosphorus and phosphorus compounds, nitrogen
and nitrogen compounds and fats, oils and greases need
not be removed provided the publicly owned treatment
works was designed to treat such pollutants and will
accept them. Otherwise levels should be at or below the
best practicable control technology currently available
for existing sources and new source performance
standards for new sources.
d. Limitation on dissolved solids is not recommended except
in cases of water quality violations.
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SECTION XII
ACKNOWLEDGEMENTS
The preparation of this report was accomplished through the
efforts of the staff of General Technologies Division,
Versar, Inc., Springfield, Virginia, under the overall
direction of Dr. Robert G. Shaver, Vice President. Mr.
Robert C. Smith, Jr., Chief Engineer, Project Officer,
directed the day-to-day work on the program.
Mr. Michael W. Kosakowski was the Project Officer. Mr.
Allen Cywin, Director, Effluent Guidelines Division, Mr.
Ernst P. Hall, Jr., Assistant Director, Effluent Guidelines
Division, and Mr. Harold B. Coughlin, Chief, Guidelines
Implementation Branch, offered many helpful suggestions
during the program. Mr. Ralph Lorenzetti assisted with many
facility inspections.
Acknowledgement and appreciation is also given to Linda Rose
and Darlene Miller (word processors) of the Effluent
Guidelines Division and the secretarial staff of the General
Technologies Division of Versar, Inc., for their efforts in
the typing of drafts, necessary revisions, and final
preparation of the effluent guidelines document.
Appreciation is extended to the following trade associations
and state and federal agencies for assistance and
cooperation rendered to us in this program:
American Mining Congress
Asbestos Information Association, Washington, D.C.
Barre Granite Association
Brick Institute of America
Building Stone Institute
Fertilizer Institute
Florida Limerock Institute, Inc.
Florida Phosphate Council
Georgia Association of Mineral Processing Industries
Gypsum Association
Indiana Limestone Institute
Louisiana Fish and Wildlife Commission
Louisiana Water Pollution Control Board
Marble Institute of America
National Clay Pipe Institute
National Crushed Stone Association
National Industrial Sand Association
National Limestone Institute
National Sand and Gravel Association
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New York State Department of Environmental Conservation
North Carolina Minerals Association
North Carolina sand. Gravel and Crushed Stone Association
Portland Cement Association
Refractories Institute
Salt Institute
State of Indiana Geological Survey
Texas Water Quality Board
U.S. Bureau of Mines
U.S. Fish and Wildlife service, Lacrosse, Wisconsin
Vermont Department of Water Resources
Appreciation is also extended to the many mineral mining and
producing companies who gave us invaluable assistance and
cooperation in this program.
Also, our appreciation is extended to the individuals of the
staff of General Technologies Division of Versar, Inc., for
their assistance during this program. Specifically, our
thanks to:
Dr. R. L. Durfee, Senior Chemical Engineer
Mr. D. H. Sargent, Senior Chemical Engineer
Mr. E. F. Abrams, Chief Engineer
Mr. L. C. McCandless, Senior Chemical Engineer
Dr. L. C. Parker, Senior Chemical Engineer
Mr. E. F. Rissman, Environmental Scientist
Mr. J. C. Walker, Chemical Engineer
Mrs. G. Contos, Chemical Engineer
Mr. M. W. Slimak, Environmental Scientist
Dr. I. Frankel, chemical Engineer
Mr. M. DeFries, Chemical Engineer
Ms. C. V. Fong, Chemist
Mrs. D. K. Guinan, Chemist
Mr. J. G. Casana, Environmental Engineer
Mr. R. C. Green, Environmental Scientist
Mr. R. S. Wetzel, Environmental Engineer
Ms. M.A. Connole, Biological Scientist
Ms. M. Smith, Analytical Chemist
Mr. M. C. Calhoun, Field Engineer
Mr. D. McNeese, Field Engineer
Mr. E. Hoban, Field Engineer
Mr. P. Nowacek, Field Engineer
Mr. B. Ryan, Field Engineer
Mr. R. Freed, Field Engineer
Mr. N. O. Johnson, Consultant
Mr. F. Shay, Consultant
Dr. L. W. Ross, Chemical Engineer
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SECTION XIII
REFERENCES
1. Agnello, L.f "Kaolin", industrial and
Chemistry, Vol. 52, No. 5, May 1960, pp7~370-376.
2. "American Ceramic Society Bulletin," Vol. 53, No. 1,
January 1974, Columbus, Ohio.
3. Bates, R. L., Geology, of the Industrial Rocks and
Minerals, Dover Publications, Inc., New York, 1969. "~
4. Boruff, C.S., "Removal of Fluorides from Drinking
Waters," Industrial and Engineering Chemistry,, Vol. 26,
No. 1, January T?347 pp. 69-71.
5. Brown, W.E., U.S. Patent 2,761,835, September 1956.
6. Brown, W.E., and Gracobine, C.R., U.S. Patent 2,761,841,
September 1956.
7. "Census of Minerals Industries", 1972, Bureau of the
Census, U.S. Department of Commerce, U.S. Government
Printing Office, Washington, D.C. MIC72(P)-14A-1
through MIC72 (P)-14E-4.
8. "Commodity Data Summaries, 1974, Appendix I To Mining
and Minerals Policy," Bureau of Mines, U.S., Department
of the Interior, U.S. Government Printing Office,
Washington, D.C.
9. "Dictionary of Mining, Mineral, and Related Terms,"
Bureau of Mines, U.S. Department of the Interior, U.S.
Government Printing Office, Washington, D.C., 1968.
10. "Engineering and Mining Journal," McGraw-Hill, October
1974. 1974.
11. Haden, W., Jr., and Schwint, I., "Attapulgite, Its
Properties and Applications," Ifidustrial and Engineering
Chemistry^ Vol. 59, No. 9, September T967, pp.~57-69.~
12. Maier, F.J., "Defluoridation of Municipal Water
Supplies," Journal AWWA, August 1953, pp. 879-888.
13. McNeal, W., and Nielsen, G., "International Directory of
Mining and Mineral Processing Operations," E/MJ,
McGraw-Hill, 1973-1974.
219
-------
14. "Minerals Yearbook, Metals, Minerals, and Fuels,
Vol. 1," U.S. Department of the Interior, U.S.
Government Printing Office, Washington, D.C., 1971,
1972.
15. "Mining Engineering, Publication of the Society of
Mining Engineers of AIME, Annual Review for 1973;"
Vol. 25, No. 1, January 1973; Vol. 26, No. 3, March 1974
through Vol. 26, No. 8, August 1974.
16. "Modern Mineral Processing Flowsheets," Denver Equipment
Company, 2nd Ed., Denver, Colorado
17. Patton, T.C., "Silica, Microcrystalline, "
Handbook Voli_1x J. Wiley and Sons, Inc., 1973,
pp. ~T 57- 15 97
18. Popper, H., Modern Engineering Cost Techniques,
McGraw-Hill, New York, 1970.
19. "Product Directory of the Refractories Industry in the
U.S.," The Refractories Institute, Pittsburgh, Pa. 1972.
20. Slabaugh, W.H., and Culbertsen, J.L., J._ Phys^ Chem..,
55, 744, 1951.
21. State Directories of the Mineral Mining Industry from 36
of 50 States.
22. Trauffer, W.E., "New Vermont Talc Facility Makes
High-Grade Flotation Product for Special Uses," Pit and
Quarry, December 1964, pp. 72-74, 101.
23. Williams, F.J., Nezmayko, M. , and Weintsitt, D.J., $J.
Phys. Chem.A 57X 8r 1953..
24. "Standard Industrial Classification Manual", Executive
Office of the President, Office of Management and
Budget, U. S, Government Printing Office, 1972.
220
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SECTION XIV
GLOSSARY
Aeration - the introduction of air into the pulp in a
flotation cell in order to form air bubbles.
Aquifer - an underground stratum that yields water.
Baghouse - chamber in which exit gases are filtered through
membranes (baqs) which arrest solids.
Bench - a ledge, which, in open pit mines and quarries,
forms a single level of operation above which mineral or
waste materials are excavated from a contiguous bank or
bench face.
Berm - a horizontal shelf built for the purpose of
strengthening and increasing the stability of a slope or
to catch or arrest slope slough material; berm is
sometimes used as a synonym for bench.
Blunge - to mix thoroughly.
Burden - valueless material overlying the ore.
Cell, cleaner - secondary cells for the retreatment of the
concentrate from primary cells.
Cell, rougher - flotation cells in which the bulk of the
gangue is removed from the ore.
Clarifier - a centrifuge, settling tank, or other device,
for separating suspended solid matter from a liquid.
Classifier, air - an appliance for approximately sizing
crushed minerals or ores employing currents of air.
Classifier, rake - a mechanical classifier utilizing
reciprocal rakes on an inclined plane to separate coarse
from fine material contained in a water pulp.
Classifier, spiral - a classifier for separating fine-size
solids from coarser solids in a wet pulp consisting of
an interrupted-flight screw conveyor, operating in an
inclined trough.
221
-------
Collector - a heteropolar compound chosen for its ability to
adsorb selectively in froth flotation and render the
adsorbing surface relatively hydrophobic.
Conditioner - an apparatus in which the surfaces of the
mineral species present in a pulp are treated with
appropriate chemicals to influence their reaction during
aeration.
Crusher, cone - a machine for reducing the size of materials
by means of a truncated cone revolving on its vertical
axis within an outer chamber, the anular space between
the outer chamber and cone being tapered.
Crusher, gyratory - a primary crusher consisting of a
vertical spindle, the foot of which is mounted in an
eccentric bearing within a conical shell. The top
carries a conical crushing head revolving eccentrically
in a conical maw.
Crusher, jaw - a primary crusher designed to reduce the size
of materials by impact or crushing between a fixed plate
and an oscillating plate or between two oscillating
plates, forming a tapered jaw.
Crusher, roll - a reduction crusher consisting of a heavy
frame on which two rolls are mounted; the rolls are
driven so that they rotate toward one another. Rock is
fed in from above and nipped between the moving rolls,
crushed, and discharged below.
Depressant - a chemical which causes substances to sink
through a froth, in froth flotation.
Dispersant - a substance (as a polyphosphate) for promoting
the formation and stabilization of a dispersion of one
substance in another.
Dragline - a type of excavating equipment which employs a
rope-hung bucket to dig up and collect the material.
Dredge, bucket - a two-pontooned dredge from which are
suspended buckets which excavate material at the bottom
of the pond and deposit it in concentrating devices on
the dredge decks.
Dredge, suction - a centrifugal pump mounted on a barge.
Drill, churn - a drilling rig utilizing a blunt-edged chisel
bit suspended from a cable for putting down vertical
holes in exploration and quarry blasting.
222
-------
Drill, diamond - a drilling machine with a rotating, hollow,
diamond-studded bit that cuts a circular channel around
a core which when recovered provides a columnar sample
of the rock penetrated.
Drill, rotary - various types of drill machines that rotate
a rigid, tubular string of rods to which is attached a
bit for cutting rock to produce boreholes.
Dryer, flash - an appliance in which the moist material is
fed into a column of upward-flowing hot gases with
moisture removal being virtually instantaneous.
Dryer, fluidized bed - a cool dryer which depends on a mass
of particles being fluidized by passing a stream of hot
air through it. As a result of the fluidization,
intense turbulence is created in the mass including a
rapid drying action.
Dryer, rotary - a dryer in the shape of an inclined rotating
tube used to dry loose material as it rolls through.
Electrostatic separator - a vessel fitted with positively
and negatively charged conductors used for extracting
dust from flue gas or for separating mineral dust from
gangues.
Filter, pressure - a machine utilizing pressure to increase
the removal rate of solids from tailings.
Filter, vacuum - a filter in which the air beneath the
filtering material is exhausted to hasten the process.
Flocculant - an agent that induces or promotes gathering of
suspended particles into aggregations.
Flotation - the method of mineral separation in which a
froth created in water by a variety of reagents floats
some finely crushed minerals, whereas other minerals
sink.
Frother - substances used in flotation to make air bubbles
sufficiently permanent, principally by reducing surface
tension.
Grizzly - a device for the coarse screening or scalping of
bulk materials.
Hydraulic Mining - mining by washing sand and dirt away with
water which leaves the desired mineral.
223
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Hydrocyclone - a cyclone separator in which a spray of water
is used.
Hydroclassifier - a machine which uses an upward current of
water -to remove fine particles from coarser material.
Humphrey spiral - a concentrating device which exploits
differential densities of mixed sands by a combination
of sluicing and centrifugal action. The ore pulp
gravitates down through a stationary spiral trough with
five turns. Heavy particles stay on the inside and the
lightest ones climb to the outside.
Jumbo - a drill carriage on which several drills are
mounted.
Kiln, rotary - a kiln in the form of a long cylinder,
usually inclined, and slowly rotated about its axis; the
kiln is fired by a burner set axially at its lower end.
Kiln, tunnel - a long tunnel-shaped furnace through which
ware is generally moved on cars, passing progressively
through zones in which the temperature is maintained for
preheating, firing and cooling.
Launder - a chute or trough for conveying powdered ore, or
for carrying water to or from the crushing apparatus.
Log washer - a slightly slanting trough in which revolves a
thick shaft or log, earring blades obliquely set to the
axis. Ore is fed in at the lower end, water at the
upper. The blades slowly convey the lumps of ore upward
against the current, while any adhering clay is
gradually disintegrated and floated out the lower end.
Magnetic separator - a device used to separate magnetic from
less magnetic or nonmagnetic materials.
Mill, ball - a rotating horizontal cylinder in which
non-metallic materials are ground using various types of
grinding media such as quartz pebbles, porcelain balls,
etc.
Mill, buhr - a stone disk mill, with an upper horizontal
disk rotating above a fixed lower one.
Mill, chaser - a cylindrical steel tank lined with wooden
rollers revolving 15-30 times a minute.
224
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Mill, hanuner - an impact mill consisting of a rotor, fitted
with movable hammers, that is revolved rapidly in a
vertical plane within a closely fitting steel casing.
Mill, pebble - horizontally mounted cylindrical mill,
charged with flints or selected lumps of ore or rock.
Mill, rod - a mill for fine grinding, somewhat similar to a
ball mill, but employing long steel rods instead of
balls to effect the grinding.
Mill, roller - a fine grinding mill having vertical rollers
running in a circular enclosure with a stone or iron
base.
Neutralization - making neutral or inert, as by the addition
of an alkali or an acid solution.
Outcrop - the part of a rock formation that appears at the
surface of the ground or deposits that are so near to
the surface as to be found easily by digging.
Overburden - material of any nature, consolidated or
unconsolidated, that overlies a deposit of useful
materials, ores, etc.
Permeability - capacity for transmitting a fluid.
Raise - an inclined opening driven upward from a level to
connect with the level above or to explore the ground
for a limited distance above one level.
Reserve - known ore bodies that may be worked at some future
time.
Ripper - a tractor accessory used to loosen compacted soils
and soft rocks for scraper loading.
Room and Pillar - a system of mining in which the
distinguishing feature is the winning of 50 percent or
more of the ore in the first working. The ore is mined
in rooms separated by narrow ribs (pillars); the ore in
the pillars is won by subsequent working in which the
roof is caved in successive blocks.
Scraper - a tractor-driven surface vehicle the bottom of
which is fitted with a cutting blade which when lowered
is dragged through the soil.
225
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Scrubber, dust - special apparatus used to remove dust from
air by washing.
Scrubber, ore - device in which coarse and sticky ore is
washed free of adherent material, or mildly
disintegrated.
Shuttle-car - a vehicle which transports raw materials from
loading machines in trackless areas of a mine to the
main transportation system.
Skip - a guided steel hoppit used in vertical or inclined
shafts for hoisting mineral.
SIC - standard industrial classification, see reference 2U.
Sink-float - processes that separate particles of different
sizes or composition on the basis of specific gravity.
Stacker - a conveyor adapted to piling or stacking bulk
materials or objects.
Slimes - extremely fine particles derived from ore,
associated rock, clay or altered rock.
Sluice - to cause water to flow at high velocities for
wastage, for purposes of excavation, ejecting debris,
etc.
Slurry - pulp not thick enough to consolidate as a sludge
but sufficiently dewatered to flow viscously.
Stope - an excavation from which ore has been excavated in a
series of steps.
Stripping ratio - the unit amount of spoil that must be
removed to gain access to a similar unit amount of ore
or mineral material.
Sump - any excavation in a mine for the collection of water
for pumping.
Table, air - a vibrating, porous table using air currents to
effect gravity concentration of sands.
Table, wet - a concentration process whereby a separation of
minerals is effected by flowing a pulp across a riffled
plane surface inclined slightly from the horizontal,
differentially shaken in the direction of the long axis
and washed with an even flow of water at right angles to
the direction of motion.
226
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Thickener - an apparatus for reducing the proportion of
water in a pulp.
TSS - Total suspended solids.
Waste - the barren rock in a mine or the part of the ore
deposit that is too low in grade to be of economic value
at the time.
Weir - an obstruction placed across a stream for the purpose
of channeling the water through a notch or an opening in
the weir itself.
Wire saw - a saw consisting of one- and three-strand wire
cables, running over pulleys as a belt. When fed by a
slurry of sand and water and held against rock by
tension, it cuts a narrow channel by abrasion.
227
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Multiply (English Units)
ENGLISH UNIT ABBREVIATION
TABLE 16
METRIC UNITS
CONVERSION TABLE
by To obtain (Metric units)
CONVERSION ABBREVIATION METRIC UNIT
K>
ro
00
B-
c
•JS
c
0
<•
&
a
x:
£
P!
y.
H
T
I
7.
H
1
O
''I
?•.
CT
O
r
^
§
acre
acre - feet
British Thermal Unit
British Thermal Unit/
pound
cubic feet/minute
cubic feet/second
cubic feet
cubic feet
cubic inches
degree Fahrenheit
feet
gallon
gallon/minute
horsepower
inches
inches of mercury
pounds
million gallons/day
mile
pound/square inch
(gauge)
square feet
square inches
tons (short)
yard
ac
ac ft
BTU
BTU/lb
cfni
cfs
cu ft
cu ft
cu in
F°
ft
ga!
gpm
hp
in
in Hg
Ib
mgd
mi
psig
sq ft
sq in
t
y
0.405
1233.5
0.252
0.555
0,028
1.7
0.028
28.32
16.39
0.555 (°F-32)*
0.3043
3.785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.609
(0.06805 psig +1)*
0.0929
6.452
0.907
0.9144
ha
cu m
kg cal
kg ca I/ kg
cu m/m?n
cu m/min
cu m
!
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu rr/day
km
arm
sq m
sq cm
kkg
m
hectares
cubic meters
kilogram - calories
kilogram caicries/kiiogram
cubic me tars/mi n Lite
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
kiilowatts
centimeters
atmospheres
kilograms
cubic rr.eters/day
kilometar
atmospheres (absolute)
square meters
square centimeters
metric tons (1000 kilograms)
meters
*Actual conversion, nor a multiplier
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