440/l-76/059a
II
Development for
Final Effluent
New
for the
MINERAL MINING AND
PROCESSING INDUSTRY
Point
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
JUNE 1976
-------
DEVELOPMENT DOCUMENT
for
INTERIM FINAL
EFFLUENT LIMITATIONS GUIDELINES
and
STANDARDS OF PERFORMANCE
MINERAL MINING AND PROCESSING INDUSTRY
Russell E. Train
Admini strator
Andrew W. Breidenbacn* Ph.D.
Assistant Administrator for
Water and Hazardous Materials
Eckardt C, Beck
Deputy Assistant Administrator for
Water Planning and Standards
Ernst P. Hall
Acting Director, Effluent Guidelines Division
Michael W. Kosakowski
Project Officer
June 1976
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, B.C. 20460
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ABSTRACT
This document presents the findings of an extensive study of the
mineral mining and processing industry for the prupose of
developing effluent limitations guidelines for existing point
sources and standards of performance and pretreatment standards
for new sources, to implement Sections 301, 304, 306 and 307 of
the Federal Water Pollution Control Act, as amended (33 U.S.C.
1551, 131U, and 1316, 86 Stat. 816 et. seg.) (the "Act").
Effluent limitations guidelines contained herein set forth the
degree of effluent reduction attainable through the application
of the best practicable control technology currently available
(BPCTCA) and the degree of effluent reduction attainable through
the application of the best available technology economically
achievable (BATEA) which must be achieved by existing point
sources by July 1, 1977 and July 1, 1983, respectively. The
standards of performance (NSPS) and pretreatment standards for
new sources contained herein set forth the degree of effluent
reduction which are achievable through the application of the
best available demonstrated control technology, processes,
operating methods, or other alternatives.
Supporting data and rationale for development of the proposed
effluent limitations guidelines and standards of performance are
contained in this report.
11
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CONTENTS
Section
Abstract
I Conclusions
II Recommendations
III Introduction
IV Industry Categorization
V Water Use and Waste Characterization
VI Selection of Pollutant Parameters
VII Control and Treatment Technology
VIII Cost, Energy and Non-Water Quality Aspects
IX Effluent Reduction Attainable Through the
Application of the Best Practicable
Control Technology Currently Available
X Effluent Reduction Attainable Through the
Application of the Best Available
Technology Economically Achievable
XI New Source Performance Standards and
Pretreatment Standards
XII Acknowledgements
XIII References
XIV Glossary
1
1
3
7
79
83
219
229
295
385
407
413
419
421
425
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FIGURES
Figure
1 Dimension Stone Distribution 14
2 Crushed Stone Distribution 18
3 Sand and Gravel Distribution 22
4 Industrial Sand Deposits 27
5 Gypsum and Asbestos Operations 33
6 Lightweight Aggregates, Mica and Sericite 33
Operations
7 Barite Processing Plants 43
8 Fluorspar Processing Plants 46
9 Potash Deposits 47
10 Borate Operations 47
11 Lithium, Calcium and Magnesium 48
12 Rock Salt Mines and wells 48
13 Phosphate Mining and Processing Locations 55
14 Sulfur Deposts 55
15 Supply-Demand Relationships for Clays 62
16 Dimension stone Mining and Processing 87
17 Crushed Stone Mining and Processing 91
18 Sand and Gravel Mining and Processing 97
19 Industrial Sand Mining and Processing 104
20 Gypsum Mining and Processing 109
21 Bituminous Limestone Mining and Processing, 112
Oil Impregnated Diatomite Mining and Processing,
and Gilsonite Mining and Processing
22 Asbestos Mining and Processing 114
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23 Wollastonite Mining and Processing 116
24 Perlite Mining and Processing, Pumice Mining and 118
Processing, and Vermiculite Mining and Processing
25 Mica Mining and Processing 121
26 Barite Mining and Processing 126
27 Fluorspar Mining and Processing 131
28 Minerals Recovery from Searles Lake, 137
Minerals Recovery at Great Salt Lake, and
Lithium Salt Recovery Natural Brine,
Silver Peak Operations
29 Borate Mining and Processing 141
30 Potassium Chloride Mining and Processing From 144
Sylvinite Ore, Langbeinite Mining and Processing,
and Potash Recovery by Solution Mining of Sylvinite
31 Trona Ore Processing by the Monohydrate 148
Process and Trona Ore Processing by the
Sesguicarbonate Process
32 Sodium Sulfate from Brine Wells 152
33 Rock Salt Mining and Processing 154
34 Phosphate Mining and Processing 157
35 Sulfur Mining and Processing (Frasch Process) 163
36 Mineral Pigments Mining and Processing 167
37 Spodumene Mining and Processing (Flotation 169
Process)
38 Bentonite Mining and Processing 173
39 Fire Clay Mining and Processing 175
40 Fuller's Earth Mining and Processing 177
41 Kaolin Mining and Processing - 180
42 Ball Mining and Processing 183
43 Feldspar Mining and Processing 185
44 Kyanite Mining and Processing 189
VI
-------
45 Magnesite Mining and Processing 192
46 Shale Mining and Processing 195
47 Aplite Mining and Processing 197
48 Talc, Steatite, Soapstone and Pyrophyllite 200
Mining and Processing
49 Talc Mining and Processing 202
50 Pyrophyllite Mining and Processing (Heavy 204
Media Separation)
51 Garnet Mining and Processing 207
52 Tripoli Mining and Processing 209
53 Diatomite Mining and Processing 211
54 Graphite Mining and Processing 214
55 Jade Mining and Processing 216
56 Novaculite Mining and Processing 218
57 Normal Distribution of Log TSS for a Phosphate 269
Slime Pond Discharge
58 Bleedwater Treating Plant 278
vii
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TABLES
Table Page
1 Recommended Limits and standards 4
2 Data Base 10
3 Production and Employment 12
1 Dimension stone by Use and Kind of Stone 15
5 Size Distribution of Crushed Stone Plants 17
6 Uses of Crushed Stone 21
7 Size Distribution of Sand and Gravel Plants 24
8 Uses of Sand and Gravel 26
9 Uses of Industrial Sand 28
10 Industry Categorization 80
11 Dimension Stone Water Use 89
12 Settling Pond Performance Stone, Sand and 236
Gravel Operations
13 Fluorspar Mine Dewatering Data 265
14 Sulfur Facilities, Comparison of Discharges 276
15 Dimension Stone Treatment Costs 300
16 Crushed Stone (Wet Process) Treatment Costs 302
17 Construction Sand and Gravel (Wet Process) 305
Treatment costs
18 Industrial Sand (Wet Process) Treatment Costs 312
19 Industrial sand (Acid and Alkaline Process) 314
Treatment Costs
20 Industrial Sand (HF Flotation) Treatment Costs 315
21 Gilsonite Treatment Costs 320
22 Vermiculite Treatment Costs 333
23 Mica Treatment Costs 325
IX
-------
24 Barite (Wet Process) Treatment Costs 330
25 Barite (Flotation Process) Treatment Costs 333
26 Fluorspar (HMS Process) Treatment Costs 335
27 Fluorspar (Flotation Process) Treatment Costs 337
28 Borates Treatment Costs 339
29 Potash (Carlsbad Operations) Treatment Costs 341
30 Potash (Moab Operations) Treatment Costs 342
31 Trona Treatment Costs 344
32 Rock Salt Treatment Costs 348
33 Phosphate Rock (Eastern) Treatment Costs 351
34 Phosphate Rock (Western) Treatment Costs 353
35 Sulfur (Anhydrite) Treatment Costs 355
36 Sulfur (On-Shore Salt Dome) Treatment Costs 357
37 Sulfur (Off-Shore Salt Dome) Treatment Costs 359
38 Mineral Pigments Treatment costs 361
39 Lithium Minerals Treatment Costs 363
40 Attapulgite Treatment Costs 365
41 Montmorillonite Treatment Costs 366
42 Montmorillonite Mine Water Treatment Costs 367
43 Wet Process Kaolin Treatment Costs 370
44 Ball Clay Treatment Costs 372
45 Wet Process Feldspar Treatment Costs 374
46 Kyanite Treatment Costs 377
47 Wet Process Talc Minerals Treatment Costs 381
48 Conversion Table 432
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SECTION I
CONCLUSIONS
This study included the non-metallic minerals given in the
following list with the corresponding Standard Industrial
Classification (SIC) code.
Dimension Stone
Crushed Stone (1422, 1423, 1429)
Construction Sand and Gravel (1442)
Industrial Sand (1446)
Gypsum (1492)
Asphaltic Minerals (1499)
a. Bituminous Limestone
b. Oil Impregnated Diatomite
c. Gilsonite
Asbestos and Wollastonite (1499)
Lightweight Aggregate Minerals (1499)
a. Perlite
b. Pumice
c. Vermiculite
Mica and Sericite (1499)
Barite (1472)
Fluorspar (1473)
Salines from Brine Lakes (1474)
Borates (1474)
Potash (1474)
Trona Ore (1474)
Phosphate Rock (1475)
Rock Salt (1476)
Sulfur (Frasch) (1477)
Mineral Pigments (1479)
Lithium Minerals (1479)
Sodium Sulfate (1474)
Bentonite (1452)
Fire Clay (1453)
Fuller's Earth (1454)
A. Attapulgite
B. Montmorillonite
Kaolin and Ball Clay (1455)
Feldspar (1459)
Kyanite (1459)
Magnesite (Naturally Occurring) (1459)
Shale and other Clay Minerals (1459)
A. Shale
B. Aplite
Talc, Soapstone, Pyrophyllite, and Steatite (1496)
Natural Abrasives (1499)
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A. Garnet
B. Tripoli
Diatomite (1499)
Graphite (1499)
Miscellaneous Non Metallic Minerals (1U99)
A. Jade
B. Novaculite
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SECTION II
R ECOMMENDATIONS
The recommended effluent limitations are listed in Table 1. The
parameter pH should be maintained between 6.0 and 9.0 units at
all times.
The pretreatment standards will not limit compatible pollutants
such as total suspended solids or pH, unless there is a problem
regulated by 40 CFR 128. Limitations for incompatible pollutants
are recommended to be the same as for best practicable control
technology currently available (for existing sources) and for new
source performance standards (for new sources).
The limitations for the following subcategories are either
promulgated or proposed at this time:
crushed stone (process and mine dewatering)
construction sand and gravel (process and mine dewatering)
industrial sand (process and mine dewatering)
gypsum (no scrubbers)
asphaltic minerals
asbestos and wollastonite
phosphate rock (process and mine dewatering)
barite (dry)
fluorspar (dry)
salines from brine lakes
borax
potash
sodium sulfate
Frasch sulfur (anhydrite)
bentonite
magnesite
diatomite
jade
novaculite
tripoli (dry)
graphite (process and mine)
All other limitations are in draft form only.
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TABLE 1
Recommended Limits and Standards
The following apply to process waste water except where noted.
Subcategory
BPCTCA
max. avg. of 30
consecutive days
max. for
any one day
Dimension stone
Mine dewateMng
Crushed stone
Mine dewaterlng
Construction Sand and Gravel
Mine dewaterlng
Industrial Sand
Dry processing,
Wet processing. &
Non HF flotation
HF flotation
No
discharge
TSS
No di scharge
TSS
No d1scharge
TSS
30 mg/1
30 mg/1
30 mg/1
BATEA and NSPS
max. avg. of 30 max. for
consecutive days any one day
No discharge
TSS 30 mg/1
NO discharge
TSS 30 mg/1
No discharge
TSS 30 mg/1
No discharge
TSS 0.023 kg/Kkg TSS 0.046 kg/kKg
No discharge
No discharge
F 0.003 kg/kkg
Mine debater ing
Gypsum
Dry &
Heavy Media Separation
Wet Scrubbers
Mine dewatering
Bituminous limestone,
011 - impregnated diatomite, &
Gl1soni te
Asbestos. Woliostonite
Mine dewaterlng
Perlite. Pumice, Vermlcultte
& Expanded lightweight aggregates
Mine dewaterlng
M1ca & Sericlte
Dry processing.
Wet processing &
Wet processing and
general clay recovery
Wet processing and
Ceramic grade clay
recovery
Mine dewaterlng
Ban te
Dry
Wet « Flotation
Tai1 ings pond
storm overflow
Mine dewaterlng
(acid)
Mine dewaterlng
(non acid)
F 0.006 kg/kkfl
TSS 30 mg/1
No d1scharge
No discharge
TSS 30 mg/1
No discharge
No discharge
TSS 30 mg/1
No discharge
TSS 30 mg/l
TSS 30 mg/1
No discharge
No discharge
TSS 30 mg/1
No discharge
No discharge
TSS 30 mg/1
No discharge
TSS 30 mg/1
No di scharge
No discharge
TSS 1.5 kg/kkg
TSS 3.0 kg/kkQ
TSS 30 mg/1
TSS 1.5 kg/kkg
TSS 3.0 kg/kkg
TSS 30 mg/J
No d1scharge
No discharge
TSS 30 mg/1
TSS 35 mg/1 TSS 70 mg/1
Total Fe 3.5 mg/1 Total Fe 7.0 mg/1
TSS 35 mg/1
No discharge
No discharge
TSS 30 mg/1
TSS 35 mg/1
Total F« 3.5 mg/1
TSS 70 mg/1
Tolal Fe 7.0 mg/1
TSS 35 mg/1
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FIuorspar
Heavy Media Separation
& Drying and Palletizing
Flotation TSS
F 0
Mine Drainage
Salines from Brine Lakes**
Borax
Potash
Trona (process waste water &
mine debater 1ng)
Sodi urn Sulfate
Rock Salt (process waste water &
mine dewatertngj TSS 0.02 kg/kkg
Sa1t pile runoff
Phosphate ROCK
Flotation unit process
No discharge
0.6 kg/kkg TSS 1.2 kg/kkg
2 Kg/kkg F 0.4 kg/kkfl
TSS 30 mg/J
No d1scharge
No di scharge
No discharge
No discharge
No di scharge
TSS 0.04 kg/kkg
and mine dewaterlng TSS
Other unit processes
Sulfur (Frasch)
fcnhydri te
Salt domes(land and TSS
marsh operations
we 11 bleed water )
Land avallable SI
Land avallabf11ty S 5
)imi tat tons
Wei 1 seal water
Mineral Pigments
Mine dewaterlng
Lithium***
Tailings dam seepage &
storm overflow
Mine dewatering
Bentoni te
Mine dewaterlng
Fire clay
Non-Acid mine dewaterlng
Acid Mine dewaterlng
Attapulgite
Mine dewaterlng
Montmor11Ion1te
Mine dewaterlng
Kaol1n
Dry processing
Wet processing
30 mg/1 TSS 60 mg/1
No discharge
No discharge
50 mg/1* TSS 100 mg/1*
mg/1
mg/1
No
No
No
No
TSS 35 mg/1
Total Fe 3.5
No
No
No
Turbidity 50
TSS 45 mg/1
Zn 0.25 mg/1
Turbidity 50
Mine dewaterlng iui-uiuii.y -
(ore slurry pumped) TSS 45 mg/1
Mine dewatertng
(ore dry transported)
S 2 mg/1
S 10 mg/1
discharge
TSS 30 mg/1
d1scharge
TSS 50 mg/1
TSS 35 mg/1
discharge
TSS 35 mg/1
di scharge
TSS 35 mg/1
TSS 70 mg/1
mg/1 Total Fe 7 mg/1
di scharge
TSS 35 mg/1
di scharge
TSS 35 mg/1
di scharge
JTU Turbldi ty 100 JTU
TSS 90 mg/1
Zn 0.50 mg/1
JTu Turbidity 100 JTU
TSS 90 mg/1
TSS 35 mg/1
No discharge
TSS 0.6 kg/kkg TSS 1.2 kg/kkg
F 0.1 kg/kkg F 0.2 kg/kkg
TSS 30 mg/1
No discharge
No discharge
No discharge
No discharge
No discharge
TSS 0.002 kg/kkg TSS 0.004 kg/kKg
No discharge
TSS 30 mg/1 TSS 60 mg/1
No discharge
TSS 30 mg/1*
S 1 mg/1
S 1 mg/1
TSS 60 mg/1*
S 2
S 2
mg/1
mg/1
TSS 30 mg/1* TSS 60 mg/1*
S 1 mg/1 S 2 mg/1
No discharge
TSS 30 mg/1
NO discharge
TSS 50 mg/1
TSS 35 mg/1
No discharge
TSS 35 mg/1
No discharge
TSS 35 mg/1
TSS 35 mg/1 TSS 70 mg/1
Total Fe 3.5 mg/1 Total Fe 7 mg/t
No discharge
TSS 35 mg/1
No discharge
TSS 35 mg/1
No discharge
Turbldi ty 50 JTU
TSS 45 mg/1
Zn 0.25 mg/1
Turbidity 50 JTU
TSS 45 mg/1
Turbtdlty 100 JTU
TSS 90 mg/1
Zn 0.50 mg/1
Turbidity 100 JTU
TSS 90 mg/1
TSS 35 mg/1
-------
Ball Clay
Dry processing
Wet processing
Mine dewaterlng
Feldspar
Non-Flotation plants
Flotation plants***
Mine dewaterlng
Kyanite
Mine dewatertng
Mageslte
Shale and Common Clay
Mine dewatering
Apllte
Mine dewaterlng
Talc. Steatite. Soapstone
Dry processing &
Washing plants
Flotation and HMS
plants
Mine dewatertng
Garnet
TrIpoli
Mine dewaterlng
01 atornite
Mine dewatermg
Graphite (process and
Mine dewaterlng)
Jade
Novacul1te
No discharge
No di scharge
TSS 35 mg/1
No d1scharge
TSS 0.6 kg/kkg TSS 1.2 kg/kkg
f 0.175 kg/kkg F 0.35 kg/kkg
TSS 30 mg/1
No di scharge
TSS 35 mg/1
No discharge
No discharge
TSS 35 mg/1
No discharge
TSS 35 mg/1
and Pyropnyl1ite
No discharge
No discharge
No discharge
TSS 35
mg/1
No discharge
TSS 0.6 kg/kkg TSS 1.2 kg/kkg
f 0.13 kg/kkg F 0.26 kg/kkg
TSS 30 mg/1
No discharge
TSS 35 mg/1
No discharge
No discharge
TSS 35 mg/1
No discharge
TSS 35 mg/1
No discharge
TSS 0.5 kg/kkg
TSS 1.0 kg/kkg
TSS 0.3 kg/kkg
TSS 30 mg/1
TSS 30 mg/! TSS 60 mg/1
No discharge
TSS 30 mg/1
No discharge
TSS 30 mg/1
TSS 10 mg/1 TSS 20 mg/1
Total Fe 1 mg/1 Total Fe 2 mg/)
No discharge
No discharge
TSS 0.6 kg/kkg
TSS 30 mg/1
TSS 60 mg/1
TSS 30 mg/1
No discharge
TSS 30 mg/1
No discharge
TSS 30 mg/1
TSS 10 mg/1 TSS 20 mg/1
Total Fe 1 mg/1 Total Fe 2 mg/1
No discharge
No discharge
pH 6-9 for all subcategories
No discharge - No discharge of process waste water pollutants
kg/kkg - kg of Pollutant/kkg of product
* standard is to apply as net 1f oxidation ditches are used and Intake Is from the same navigable
water as the discharge.
** standards are to be applied as net 1? discharge 1s to the sam« navigable water as brine Intake
*** kg of pollutant/kkg of ore processed
BPCTCA - best practicable control technology currently available
BATEA - best available technology economically achievable
NSPS - new source performance standard
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SECTION III
INTRODUCTION
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 waters
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 304(b) of the Act. Section
301(b) also reguires 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) of 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,
operating methods and other alternatives. The regulations
proposed herein set forth effluent limitations guidelines
pursuant to Section 304(b) of the Act for the minerals for the
construction industry segment of the mineral mining and
processing industry point source category. 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 Administrator published in the Federal Register
of January 16, 1973 (38 F.R. 1624), a list of 27 source
-------
categories. Publication of an amended list on October 16, 1975
in the Federal Register constituted 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 products covered in this report are listed below with their
SIC designations:
Dimension stone (1411)
Crushed stone (1422, 1423, 1429, 1499)
Construction sand and gravel (1442)
Industrial sand (1446)
Gypsum (1492)
Asphaltic Minerals (1499)
Asbestos and Wollastonite (1499)
Lightweight Aggregates (1499)
Mica and Sericite (1499)
Barite (1472 and 3295)
Fluorspar (1473 and 3295)
Salines from Brine Lakes (1974)
Borax (1474)
Potash (1474)
Trona Ore (1474)
Phosphate Rock (1475)
Rock Salt (1476)
Sulfur (1477)
Mineral Pigments (1479)
Lithium Minerals (1479)
Sodium Sulfate (1474)
Bentonite (1452)
Fire Clay (1453)
Fuller's Earth (1454)
Kaolin and Ball Clay (1455)
Feldspar (1459)
Kyanite (1459)
Magnesite (1459)
Shale and other clay minerals, N.E.C. (1459)
Talc, Soapstone and Pyrophyllite (1496)
Natural abrasives (1499)
Diatomite mining (1499)
Graphite (1499)
Miscellaneous non-metallic minerals,
N.E.C. (1499)
Some of the above minerals which are processed only (SIC 3295)
are also included.
-------
The data for identification and analyses were derived from a
number of sources. These sources included EPA research
information, published literature, qualified technical
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. Table 2
summarizes the data base for the various subcategories in this
volume. The 1972 production and employment figures in Table 3
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.
DIMENSION STONE (SIC 1411)
Rock which has been specially cut or shaped for use in buildings,
monuments, memorial and gravestones, curbing, or other
construction or special uses is called dimension stone. Large
quarry blocks suitable for cutting to specific dimensions are
also classified as dimension stone. The principal dimension
stones are granite, marble, limestone, slate, and sandstone.
Less common are diorite, basalt, mica schist, quartzite, diabase
and others.
Terminology in the dimension stone industry is somewhat ambiguous
and frequently does not correspond to the same terms used in
mineralogical rock descriptions. Dimension granites include not
only true granite, but many other types of igneous and
metamorphic rocks such as quartz diorites, syenites, quartz
porphyries, gabbros, schists, and gneisses. Dimension marble may
be used as a term to describe not only true marbles, which are
metamorphosed limestones, but also any limestone that will take a
hicrh polish. Many other rocks such as serpentines, onyx,
travertines, and some granites are frequently called marble by
the dimension stone industry. Hard cemented sandstones are
sometimes called quartzite although they do not specifically meet
the mineralogical definition.
Many of the States possess dimension stone of one kind or other,
and many have one or more producing operations. However, only a
few have significant operations. These are as follows:
Granite - Minnesota
Georgi a
Vermont
Massachusetts
South Dakota
Marble - Georgia
Vermont
Minnesota (dolomite)
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TABLE 2
DATA BASE
Subcategory
No.
Plants
Dimension Stone 194
Crushed Stone
Dry 3,200
Wet 1,600
Flotation 8
Shell Dredging 50
Construction Sand
Gravel
Dry 750
Wet A,250
Dredging (on-land) 50
Dredging (on-board) 100
Industrial Sand
Dry 20
Wet 130
Flotation (Acid & 17
Alkaline)
Flotation (HF) 1
Gypsum
Dry 73
Wet Scrubbing 5
HMS 2
Asphaltic Minerals
Bituminous Limestone 2
Oil Impreg.Diatomite 1
Gilsonite 1
Asbestos
Dry 4
Wet 1
Wollastonite 1
Lightweight Aggregates
Perlite 13
Pumice 7
Vermiculite 2
Mica & Sericite
Dry 7
Wet 3
Wet Beneficiation 7
Barite
Dry 9
Wet 14
Flotation 4
Fluorspar
HMS 6
Flotation 6
Drying and 2
Pelletizing
No Plants
Visited
20
5
26
2
4
0
46
8
3
0
3
4
1
5
1
1
0
1
1
2
1
1
4
2
2
5
2
5
4
7
3
4
4
1
Data
Available
20
52
130
3
4
50
100
15
25
5
10
10
1
54
8
2
2
1
1
4
1
1
4
7
2
7
3
7
8
14
4
6
5
2
Sampled
5
*
9
1
0
*
15
0
0
*
2
2
1
2
1
*
*
*
1
1
*
*
*
*
*
*
*
*
*
1
*
2
*
10
-------
Salines from
Brine Lakes
Borax
Potash
Trona Ore
Phosphate Rock
Eastern
Western
Koc* «alt
Sulfur
Anhydrite
On-Shore
Off-Shore
Mineral
Pigments
Lithium
Minerals
Sodium
Sulfate
Bentonite
Fire Clay
Fuller's Earth
Attapulgite
Montmor .
Kaolin
Dry
Wet
Ball Clay
Feldspar
Wet
Dry
Kyanite
Magnesite
Shale and Common
Clay
Aplite
Talc Minerals
Dry
Washing
EMS, Flotation
Natural Abrasives
Garnet
Tripoli
Diatomite
Graphite
Misc. Minerals
Jade
Novaculite
1
5
4
22
6
21
2
9
2
11
2
6
37
81
10
4
37 total
12
5
2
3
1
129
2
27
2
4
3
4
9
1
est. 10
1
1
4
2
21
6
11
1
7
1
3
2
2
2
9
4
3
4
6
4
5
2
2
1
10
2
12
1
4
2
2
3
1
1
1
Total
11,019
312
1
5
4
20.
6
15
2
9
1
3
2
9
5
3
4
7
4
5
2
2
1
20
20
2
4
2
4
3
1
1
1
735
3
a
3
5
1
2
3
*
0
0
5
*
*
*
0
*
77
*There is no discharge of process waste water in the subcategories
under normal operating conditions.
11
-------
TABLE 3
Production and Employment
SIC Code Product
1411 Dimension stone-limestone
1411 Dimension stone-granite
1411 Dimension stone-other*
1422 Crushed & broken stone-
limestone
1423 Crushed & broken stone
granite
1429 Crushed & broken stone NEC
1499 Crushed & broken stone shell
1442 Construction sand & gravel
1446 Industrial sand
1492 Gypsum
1499 Bituminous limestone
1499 Oil-impregnated diatomite
1499 Gilsonite
1499 Asbestos
1499 Wollastonite
1499 Perlite
1499 Pumice
1499 Vermiculite
1499 Mica
1472 Barite
1473 Fluorspar
1474 Borates
1474 Potash (K2) equiv.
1474 Soda Ash "(trona only)
1474 Sodium sulfate
1475 Phosphates
1476 Salt (mined only)
1477 Sulfur (Frasch)
1479 Mineral pigments
1479 Lithium minerals
1452 Bentonite
1453 Fire clay
1454 Fuller's earth
1455 Kaolin
1455 Ball clay
1459 Feldspar
1459 Kyanite
1459 Magnesite
1459 Aplite
1459 Crude common clay
1496 Talc
1496 Soapstone
1496 Pyrophyllite
1499 Abrasives
Garnet
Tripoli
1499 Diatomite
1499 Graphite
1499 Jade
1499 Novaculite
*Sandstone, marble, et al
**Includes ball clay
1272 Production
tOte-Kfcg 1000 tons
542
357
559
542,400
95,900
113,000
19,000
650,000
27,120
11,200
1 ,770
109
45
120
63
589
3,460
306
145
822
228
1,020
^,410
2,920
636
37,000
12,920
7,300
63
Withheld
2,150
3,250
896
4,810
612
664
Est. 108
Withheld
190
41 ,840
1,004
17
80
522
Withheld
.107
Withheld
598
394
616
598,000
106,000
124,600
20,900
717,000
29,999
12,330
1,950
120
50
132
70
649
3,810
337
160
906
251
1,120
2,660
3,220
701
40,800
14,200
8,040
70
2,767
3,581
988
5,318
675
732
Est. 120
210
46,127
19
88
576
.118
Employment
2,000 combined
SIC 1411
29,400
4,500
7,400
Unknown
30,300
4,400
2,900
Unknown
Unknown
Unknown
400
70
100
525
225
75
1,025
270
1,800
1,200
1,070
100
4,200
2,800
2,900
Unknown
approx. 250
900
500
1,200
3,900**
450
165
Unknown
Unknown
2,600
950
Unknown
Unknown
500
54
Unknown
15
12
-------
Limestone - Indiana
- Wisconsin
Slate - Vermont
New York
Virginia
Pennsylvania
Sandstone,- Pennsylvania
Quartz, and Ohio
Quartzite New York
Figure 1 gives the U. S. production on a state basis for granite,
limestone, sandstone, quartz and quartzite which are the
principal stones quarried as shown in Table 4. There are less
than 500 dimension stone mininq activities in the U.S. Present
production methods for dimension stone ranqe from the inefficient
and antiquated to the technologically modern. Quarrying methods
include the use of various combinations of wire saws, jet
torches, channeling machines, drilling machines, wedges, and
broaching tools. The choice of equipment mix depends on the type
of dimension stone, size and shape of deposit, production
capacity, labor costs, financial factors, and management
attitudes.
Blasting with a low level explosive, such as black powder, is
occasionally done. Blocks cut from the face are sawed or split
into smaller blocks for ease in transportation and handling. The
blocks are taken to processing facilities, often located at the
quarry site, for final cutting and finishing operations. Stone
finishing equipment includes: (a)gang saws (similar to large hack
saws) used with water alone or water with silicon carbide (SiC)
abrasive added, and recently, with industrial diamond cutting
edges; (b)wire saws used with water alone, or with water and
quartz sand, or water with SiC; (c)diamond saws; (d)profile
grinders; (e)guillotine cutters; (f)pneumatic actuated cutting
tools (chisels); (g)sand blasting and shot peening; and
(h) polishing mills.
CRUSHED STONE (SIC 1422, 1423 and 1429)
This stone category pertains to rock which has been reduced in
size after mininq to meet various consumer requirements. As with
dimension stone, the terminology used by the crushed stone
producing and consuming industries is not consistent with
mineralogical definitions. Usually all of the coarser grained
igneous rocks are called granite. The term traprock pertains to
all dense, dark, and fine-grained igneous rocks. Quartzite may
describe any siliceous-cemented sandstone whether or not it meets
the strict mineralogical description. Approximately three-
fourths of all crushed stone is limestone.
13
-------
FIGURE 1
DIMENSION STONE DISTRIBUTION
DIKENStOMM, C
1972- 1000 uliort tone
* Producing States (total • 214) Data from: Minerals Yearbook- 1972,
National Total - 621.2 Vol. I, Table 5, p. 1164
DIMENSIONAL LIMESTONE
* Producing States (Total * 54.8) Data from: Minerals Yearbook
National Total - 411.1 (excluding P.R.) 1972, Vol,,I, Table 6,p. 1164
DIMENSIONAL SANDSTONE,
QUARTZ, QUARTZITE
* ProducinR States (Total - 22.3) Dnta from: Minerals Yearbook-1072
National Total - 230.7 Vol.I, Table 7, p.l
14
-------
TABLE 4
DIMENSION STONE BY USE AND KIND OF STONE
(1972)
Kind of stone end use
GRANITE
1000 short tctus
Kind of stone and use
continued
Dressed:
1000 short tons
Rough :
Architectural
Construction
Monumental
Other rough stone
Dressed :
Cut
Sawed
House stone veneer
Construction
Monumental
Cvirbing
Flagging
Paving blocks
Other dressed stone
Total
Value ($1000)
LIMESTONE AKD DOLOMITE
Rough :
Architectural
Construction
Flagging
Other roufth stone
Dressed:
Cut
Saved
House stone veneer
Construction
Flagging
Other dressed stone
Total
Value ($1000)
MARBLE
Rough i Architectural
Dressed:
Cut
Sawed
Kouda stone veneer
Construction and Monumental
Total
Value ($1000)
SANDSTONE, QUAKTZ & QUARTZITE
Rough:
Architectural
Coniitructiun
Flucglng
Other rough stone
46
54
287
__
—
14
6
10
33
130
—
—
42
621
42,641
175
56
18
1
49
30
68
12
2
1
411
14,378
9
21
S
9
27
71
16. 541
42
74
18
1
Cut
Curbing
Sawed
House stone veneer
Flagging
Other uses not listed
Total
Value ($1000)
SLATE
Roofing slate
Mlllstock:
Structural and sanitary
Blackboards, etc.
Billinrd table tops
Total
Flagging
Other uses not listed
Total
Value ($1000)
OTHER STONE
Rough :
Architectural
Construction
Dressed:
Cut
Construction
Flagging
Structural and sanitary purpose*
Total
Value ($1000)
TOTAL STONE
Rough I
Architectural
Construction
Monumental
Flagging
Other rough stone
Uroseed:
Cut
Saved
House stone veneer
Construction
Roofing (slate)
Millstock (elate)
Monumental
Curbing
Flogging
Other UBCO not lilted
Total
Value ($1000)
21
—
_~
27
17
32
231
7,684
12
14
1
4
19
36
14
80
7,404
U
43
2
4
66
1,964
286
239
287
36
2
117
65
no
32
12
19
65
130
61
31
1,490
90,763
Minerals Y
-------
Riprap is large irregular stone used chiefly in river and harbor
work and to protect highway embankments. Fluxing stone is
limestone, usually 4 to 6 inches in cross section, which is used
to form slag in blast furnaces and other metallurgical processes.
Terrazzo is sized material, usually marble or limestone, which is
mixed with cement for pouring floors and is smoothed to expose
the chips after the floor has hardened. Some guartzose rock is
also used for flux. Stucco dash consists of white or brightly
colored stone, 1/8 to 3/8 inches in size, for use in stucco
facing. Ground limestone is used to significantly reduce the
acidity of soils.
The crushed stone industry is widespread and varied in size of
facilities and types of material produced. The size of
individual firms varies from small independent producers with
single facilities to large diversified corporations with 50 or
more crushed stone facilities as well as other important
interests. Facility capacities range from less than 22,700
kkg/yr (25,000 tons/yr) to about 13.6 million kkg/yr (15 million
tons/yr). As Table 5 shows only about 5.2 percent of the
commercial facilities are of a 816,000 kkg (900,000 ton) capacity
or larger, but these account for 39.5 percent of the total
output. At the other extreme, facilities of less than 22,700 kkg
(25,000 ton) annual capacity made up 33.3 percent of the total
number but produce only 1.3 percent of the national total.
Geographically, the facilities are widespread with all States
reporting production. In general, stone output of the individual
States correlates with population and industrial activity as
shown by Figure 2. This is true because of the large cost of
shipment in relation to the value of the crushed stone.
Most crushed and broken stone is presently mined from open
guarries, but in many areas underground mining is becoming more
frequent. Surface mining equipment varies with the type of
stone, the production capacity needed, size and shape of
deposits, estimated life of the operation, location of the
deposit with respect to urban centers, and other important
factors. Ordinarily, drilling is done with tricone rotary
drills, long-hole percussion drills including "down the hole"
models, and churn drills. Blasting in smaller operations may
still be done with dynamite, but in most sizable operations
ammonium nitrate-fuel oil mixtures (AN/FO) are used, which are
much lower in cost. Secondary breakage increasingly is done with
mechanical equipment such as drop hammers to minimize blasting in
urban and residential areas.
Underground operations are becoming more common as the advantages
of such facilities are increasingly recognized by the producers.
Underground mines can be operated on a year-round, uninterrupted
basis; do not require extensive removal of overburden; do not
produce much if any waste requiring subsequent disposal; require
little surface area which becomes of importance in areas of high
16
-------
TABLE 5
SIZE DISTRIBUTION OF CRUSHED STONE PLANTS*
ANNUAL PRODUCTION
TONS
NUMBER OF
QUARRIES
TOTAL ANNUAL
PRODUCTION
1000 TONS
PERCENT
OF TOTAL
25,000
50,000
75,000
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
< 25,000
- 49,999
- 74,999
- 99,999
- 199,999
- 299,999
- 399,999
- 499,999
- 599,999
- 699,999
- 799,999
- 899,999
> 900,000
1,600
600
339
253
634
308
233
182
126
98
76
51
248
13,603
24,221
20,485
21,941
90,974
75,868
80,946
80,956
68,903
62,730
56,694
42,718
418,502
1.3
2.3
1.9
2.1
8.6
7.2
7.6
7.7
6.5
5.9
5.4
4.0
39.5
TOTAL
4,808
1,058,541
100,0
U.S. Deaprtment of the Interior
Bureau of Mines
Division of Nonmetallic Minerals
1973
17
-------
FIGURE 2
CRUSHED STONE DISTRIBUTION
CRUSHED GRANITE
1972/1,000.000 short tons
* Other producing States (tota.1 • 13.9)
National Total - 106.3
Dat» From: Minerals Yearbook - 1972. Vol. I
Table 11. p. 1168
CRUSHED LIMESTONE
AND DOLOMITE
1972/1.000.000 short tons
*• Total stone - crushed * dimensional
* Other producing States (total • 8.2)
National total (excluding P.ft. i territories) • 663.3
'Pacific Islands • .9
Data From: Mineral Yearbook - 1972. Vol. I
Table 13, p. 1170
18
-------
land cost and finally, greatly reduce the problems of
environmental disturbance and those of rehabilitation of
mined-out areas. An additional benefit from underground
operations, as evidenced in the Kansas City area, is the value of
the underground storage space created by the mine - in many cases
the sale or rental of the space produces revenue exceeding that
from the removal of the stone.
Loading and hauling equipment has grown larger as increasing
demand for stone has made higher production capacities necessary.
Track-mounted equipment is still used extensively but pneumatic-
tire-mounted hauling equipment is predominant.
Crushing and screening facilities have become larger and more
efficient, and extensive use is made of belt conveyors for
transfer of material from the pits to the loading-out areas.
Bucket elevators are used for lifting up steep inclines. Primary
crushing is often done at or near the pit, usually by jaw
crushers or gyratories, but impact crushers and special types may
be used for nonabrasive stone, and for stone which tends to clog
the conventional crushers. For secondary crushing a variety of
equipment is used depending on facility size, rock type, and
other factors. Cone crushers and gyratories are the most common
types. Impact types including hammer mills are often used where
stone is not too abrasive. For fine grinding to produce stone
sand, rod mills predominate.
For screening, inclined vibrating types are commonly used in
permanent installations, while horizontal screens, because they
require less space, are used extensively in portable facilities.
For screening large sizes of crushed stone, heavy punched steel
plates are used, while woven wire screens are used for smaller
material down to about one-eighth of an inch. Air and hydraulic
separation and classifying equipment is ordinarily used for the
minus 1/8 inch material.
Storage of finished crushed stone is usually done in open areas
except for the small quantities that go to the load-out bins. In
the larger and more efficient facilities the stone is drawn out
from tunnels under the storage piles, and the eguipment is
designed to blend any desired mixture of sizes that may be
needed.
Oyster shells, being made of very pure calcium carbonate, are
dredged for use in the manufacture of lime and cement. The
industry is large and active along the Gulf Coast, especially at
New Orleans, Lake Charles, Houston, Freeport, and Corpus Christi.
In Florida, oyster shell was recovered from fossil beds offshore
on both Atlantic and Gulf coasts. Production in 1957 amounted to
1,364,000 kkg (1,503,964 tons), used principally for road metal
and a small amount as poultry grit. This figure included
coquina, a cemented shell rock of recent but not modern
19
-------
geological time, which is dredged for the manufacture of cement
near Bunnell in Flagler County. It is used widely on lightly
traveled sand roads along the east coast. Clam shells used to be
dredged from fresh water streams in midwestern states for the
manufacture of buttons, but the developments in the plastics
industry have impacted heavily. Table 6 gives a breakdown of the
end uses of crushed stone. The majority of crushed stone is used
in road base, cement and concrete.
CONSTRUCTION SAND AND GRAVEL (SIC 1442)
Sand and gravel are products of the weathering of rocks and thus
consist predominantly of silica but often contain varying amounts
of other minerals such as iron oxides, mica and feldspar. The
term sand is used to describe material whose grain size lies
within the range of 0.065 and 2 mm and which consists primarily
of silica but may also include fine particles of any rocks,
minerals and slags. Gravel consists of naturally occurring rock
particles larger than about 4 mm but less than 64 mm in diameter.
Although silica usually predominates in gravel, varying amounts
of other rock constituents such as mica, shale, and feldspar are
often present. Silt is a term used to describe material finer
than sand, while cobbles and boulders are larger than gravel.
The term "granules" describes material in the 2 to 4 mm size
range. The descriptive terms and the size ranges are somewhat
arbitrary although standards have to some extent been accepted.
For most applications of sand and gravel there are specifications
for size, physical characteristics, and chemical composition.
For construction uses, the specifications depend on the type of
construction (concrete or bituminuous roads, dams, and buildings)
the geographic area, architectural standards, climate, and the
type and guality of sand and gravel available.
In summary for the glaciated areas in the northern States, and
for a hundred miles or more south of the limit of glacial
intrusion, the principal sand and gravel resources consist of
various types of outwash glacial deposits and glacial till.
Marine terraces, both ancient and recent are major sand and
gravel sources in the Atlantic and Gulf Coastal Plains. River
deposits are the most important sand and gravel sources in
several of the Southeastern and South Central States. Abundant
sand and gravel resources exist in the mountainous areas and the
drainage from the mountains has created deposits at considerable
distances from the initial sources. Great Plains sand and gravel
resources consist mainly of stream-worked material from existing
sediments. On the West Coast, deposits consist of alluvial fans,
river deposits, terraces, beaches, and dunes. Figure 3 shows the
production and facility distribution for the United States.
20
-------
TABLf 6
USES OF CRUSHED. STONE
Kind of Mtonc d roadstone 3,281
Cement and lire nianufatture 5,67^
Other uses 5,98«
Total 16, «0
Value ($1000) 29,571
TRAPROCK
Agricultural purposes ******
Concrete aggregate (coarse) 6,643
Bituminous aggregate 11,469
Macadam aggret'.tjte 1,438
Dense graded road base stone 19,361
Surface treatment aggregate 5,341
Unspecified construction aggregate and roadstono 23,811
Riprap and jc'tty stone 3,673
Railr id bailout 2,332
Filter stone 117
Manufactured fine aggregate (stone sand) 231
Fill 1.686
Other uses 3,966
Total 80,462
Value ($1000) 170,823
OTHER STONE
Concrete aggregate (cjarse) 1,159
Bituminous aggregate 2,202
Macadam aggregate 278
Dense graded raod base stone 3,051
Surface treatment aggregate 591
Unspecified construction aggregate and roadstone 2,911
Riprap and jetty stone 1,738
Railroad ballast —
Mineral filJers, extenders and whiting
Fill 578
Other uses 1,789
Total U.298
Value ($1000) 24,442
TOTAL STONE
Agricultural purposes 23,393
Concrete aggregate (coarse) 133,473
Bituminous Aggregate 82,560
Macadam aggregate 33,110
iJenoe graded road base stone 210,013
Surface treatment a£xregate 51,943
Unspecified construction aggregate and roadstonc 113,406
Riprap and jetty stone 24,560
Railioad ballast 18,021
Filter stone 636
Manufactured tine aggregate (stone sand) 5,869
Terrazzo and exposed aggregate 402
Cement r.anul.ic turc 108,857
Lime iranufacturc 30,051
Dead-burned dolomite 1,670
Fertoalllcon 1,257
Flux stone 25,830
Ketrnctory stone 605
Chemical stone for alkali worko 4,199
Special uiiea and products 1,071
Mineral tillers, extenders and whiting 4,423
Fill 6,630
CJfiBB 2,718
Expanded ulatc 1,270
Other IKJCB 31,394
Total 922,361
Value- ($1()',0) 1,592,569
Htnoraln Yr>ai lii-nlt
H'ji ,>«u nf Mint'n
J','72, U.S. Uriuitiuvnt
l.h«' Interior
21
-------
FIGURE 3
SAND AND GRAVEL DISTRIBUTION
PRODUCTION
1972/1,000,000 short tons
Nation*! Tot*l (excluding P.R.) • 913.2
Data From: Minerals Yearbook - 1972, Vol. t
Table 3. o. 1111-1112
Bureau of Mines
Data From: Minerals Yearbook - 1972
Vol II
Bureau of Mines
22
-------
The crushed stone and sand and gravel industries, on the basis of
tonaqe are the largest nonfuel mineral industries. Because of
their widespread occurrence and the necessity for producing sand
and gravel near the point of use, there are more than 5,000 firms
engaged in commercial sand and gravel output, with no single firm
being large enough to dominate the industry. Facility sizes
range from very small producers of pit-run material to highly
automated permanent installations capable of supplying as much as
3.6 million kkg (<* million tons) yearly of closely graded and
processed products; the average commercial facility capacity is
about 108,000 kkg/yr (120,000 tons/yr). As seen from Table 7
about 40 percent of all commercial facilities are of less than
22,600 kkg (25,000 tons) capacity, but together these account for
only 4 percent of the total commercial production. At the other
extreme, commercial operations with production capacities of more
than 907,000 kkg (1 million tons) account for less than 1 percent
of the total number of facilities and for 12 to 15 percent of the
commercial production.
Geographically the sand and gravel industry is concentrated in
the large rapidly expanding urban areas and on a transitory
basis, in areas where highways, dams, and other large-scale
public and private works are under construction. Three-fourths
of the total domestic output of sand and gravel is by commercial
firms, and one-fourth by Government-and-contractor operations.
California leads in total sand and gravel production with a 1972
output more than double that of any other State. Production for
the State in 1968 was 113 million kkg (125 million tons), or 1H
percent of the national total. Three of the 10 largest producing
firms are located in California. The next five producing States
with respect to total output all border on the Great Lakes, where
ample resources, urban and industrial growth, and low-cost lake
transportation are all favorable factors.
Mining equipment used varies from small, simple units such as
tractor-mounted high-loaders and dump trucks to sophisticated
mining systems involving large power shovels, draglines,
bucket-wheel excavators, belt conveyors and other components.
Sand and gravel is also dredged from river and lake bottoms rich
in such deposits.
Processing may consist of simple washing to remove clay and silt
and screening to produce two or more products, or it may involve
more complex heavy medium separation of slate and other
lightweight impurities and complex screening and crushing
equipment designed to produce the optimum mix of salable sand and
gravel sizes. Conveyor belts, bucket elevators, and other
transfer equipment are used extensively. Ball milling is often
required for production of small-size fractions of sand.
Permanent installations are built where large deposits are to be
operated for many years. Semiportable units are used in many
23
-------
TABLE 7
Size Distribution of Sand and Gravel Plants
Production
Thousand Percent
Annual Production
(short tons)
Less than 25,000
25,000 to 50,000
50,000 to 100,000
100,000 to 200,000
200,000 to 300,000
300,000 to 400,000
400,000 to 500,000
500,000 to 600,000
600,000 to 700,000
700,000 to 800,000
800,000 to 900,000
900,000 to 1,000,000
1,000,000 and over
Plants
Number
1,630
850
957
849
400
217
134
79
71
56
26
27
88
short
tons
17,541
30,508
68,788
121,304
97,088
75,157
59,757
42,924
46,036
41,860
22,310
25,666
136,850
of
total
2.2
3.9
8.8
15.4
12.4
9.6
7.6
5.5
5.9
5.3
2.8
3.3
17.3
Total
5,384
785,788
100.0
Minerals Yearbook, 1972, U.S. Department of the Interior,
Bureau of Mines, Vol I, page 1120
-------
pits which have an intermediate working life. Several such units
can be tied together to obtain large initial production capacity
or to add capacity as needed. In areas where large deposits are
not available, use is made of mobile screening facilities, which
can be quickly moved from one deposit to another without undue
interruption or loss of production. Table 8 breaks down the end
uses of sand and gravel.
INDUSTRIAL SAND (SIC 1446)
Industrial sands includes those types of silica raw materials
that have been segregated and refined by natural processes into
nearly monomineralic deposits and hence, by virtue of their high
degree of purity, have become the sources of commodities having
special and somewhat restricted commercial uses. In some
instances, these raw materials occur in nature as unconsolidated
quartzose sand or gravel and can be exploited and used with very
little preparation and expense. More often, they occur as
sandstone, conglomerate quartzite, quartz mica schist, or massive
igneous quartz which must be crushed, washed, screened, and
sometimes chemically treated before commodities of suitable
composition and texture can be successfully prepared. Industrial
silica used for abrasive purposes falls into three main
categories: (a) blasting sand; (b) glass-grinding sand; and (c)
stonesawing and rubbing sand. Figure 4 locates the domestic
industrial sand deposits. Table 9 gives the breakdown of the
uses of industrial sand.
Blasting sand is a sound closely-sized quartz sand which, when
propelled at high velocity by air, water, or controlled
centrifugal force, is effective for such uses as cleaning metal
castings, removing paint and rust, or renovating stone veneer.
The chief sources of blasting sands are in Ohio, Illinois,
Pennsylvania, West Virginia, New Jersey, California, Wisconsin,
South Carolina, Georgia, Florida, and Idaho.
Glass-grinding sand is clean, sound, fine to medium-grained
silica sand, free from foreign material and properly sized for
either rough grinding or semifinal grinding of plate glass. Raw
materials suitable for processing into these commodities comprise
deposits of clean, sound sand, sandstone, and quartzite. As this
commodity is expensive to transport sources of this material
nearest to sheet and plate glass facilities are the first to be
exploited.
Stonesawing and rubbing sand is relatively pure, sound, well-
sorted, coarse-grained, siliceous material free from flats and
fines. It is used for sawing and rough-grinding dimension stone.
Neither textural nor quality specifications are rigorous on this
type of material as long as it is high in free silica and no
clay, mica, or soft rock fragments are present. Chert tailings,
known as chats in certain mining districts, are used successfully
25
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Table 8
Uses of Sand and Gravel
Use Quantity
1000 kkg 1000 short tons
Building
Sand 170,329 187,794
Gravel 139,001 153,25A
Paving
Sand 119,182 131,402
Gravel 254,104 280,159
Fill
Sand 44,050 48,567
Gravel 39,416 43,458
Railroad Ballast
Sand 948 1,045
Gravel 2,022 2,229
Other
Sand 8,685 9,575
Gravel 11,682 12,880
Total 789,419 870,363
Value ($1000) 1,069,374
Value ($/Quantity) 1.35 1.23
Minerals Yearbook, 1972, U.S. Department of the Interior
Bureau of Mines
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FIGURE 4
INDUSTRIAL SAND DEPOSITS
From Glass Sand and Abrasives chart-pg.184
The National Atlas of The USA
USGS-1970
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Table 9
Uses of Industrial Sand
Use
Quantity
1000 kkg 1000 short tons
Value
$/kkg $/ton
Unground
Glass
Molding
Grinding and polishing
Blast sand
Fire or furnace
Engine (RR)
Filtration
Oil Hydrofrac
Other
Ground Sand
Total
9821
6822
238
972
638
545
212
256
3187
4092
26784
10828
7522
262
1072
703
601
234
282
3514
4512
29530
4.20
3.64
3.08
6.46
3.52
2.54
5.53
4.18
3.73
3.81
3.30
2.79
5.86
3.19
2.30
5.02
3.79
3.38
5.26
4.20
4.77
3.81
Minerals Yearbook, 1972, U.S. Department of the Interior,
Bureau of Mines
28
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in some regions as stonesawing and rubbing sand. River terrace
sand, and glacial moraine materials, which have been washed and
screened to remove oversize and fines, are often employed.
Several important marble and granite producing districts are
quite remote from sources of clean silica sand and are forced to
adapt to less efficient sawing and grinding materials.
Glass-melting and chemical sands are quartz sands of such high
purity that they are essentially monomineralic; permissible trace
impurities vary according to use. Grain shape is not a critical
factor, but size frequency distribution can vary only between
narrow limits. Appropriate source materials are more restricted
than for any other industrial silica commodity group. Because
the required products must be of superlative purity and
consequently are the most difficult and expensive to prepare,
they command higher prices and can be economically shipped
greater distances than nearly any other class of special sand.
To qualify as a commodity in this field the product must be a
chemically pure quartz sand essentially free of inclusions,
coatings, stains, or detrital minerals. Delivery to the customer
in this highly refined state must be guaranteed and continuing
uniformity must be maintained. At the present time the principal
supply of raw materials for these commodities comes from two
geological formations. The Oriskany quartzite of Lower Devonian
aqe occurs as steeply dippinq beds in the Appalachian Highlands.
Production, in order of importance, is centered in West Virqinia,
Pennsylvania, and Virginia. The St. Peter sandstone of Lower
Ordovician age occurs as flatlying beds in the Interior Plains
and Hiqhlands and is exploited in Illinois, Missouri, and
Arkansas.
Metallurgical pebble is clean graded silica in gravel sizes that
is low in iron and alumina. It is used chiefly as a component in
the preparation of silicon alloys or as a flux in the preparation
of elemental phosphorus. A quartzite or quartz gravel to qualify
as a silica raw material must meet rigorous chemical
specifications. Metallurgical gravel is no exception, and in the
production of silicon alloys, purity is paramount. Such alloys
as calcium-silicon, ferrosilicon, silicon-chrome, silicon copper,
silicomanganese, and silicon-titanium are the principal products
prepared from this material. The better deposits of
metallurgical grade pebble occur principally as conglomerate beds
of Pennsylvanian age, and as gravelly remnants of old river
terraces developed from late Tertiary to Recent times. The
significant producing area is in the Sharon conglomerate member
of the Pottsville formation in Ohio. Silica pebble from the
Sewanee conglomerate is produced in Tennessee for alloy and flux
use. Past production for metallurgical use has come from the
Olean conglomerate member of the Pottsville formation in New
York, and the Sharon conglomerate member of the Pottsville
formation in Pennsylvania. Production from terrace gravels is
done in North Carolina, Alabama, South Carolina, and Florida in
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roughly decreasing order of economic importance. Marginal
deposits of coarse quartzose gravel occur in Kentucky. Terrace
deposits of vein guartz gravel in California have supplied
excellent material for ferrosilicon use.
Industrial silica used principally for its refractory properties
in the steel and foundry business is of several types: core sand,
furnace-bottom sand, ganister mix, naturally bonded molding sand,
processed molding sand, refractory pebble, and runner sand. A
foundry sand used in contact with molten metal must possess a
high degree of refractoriness; that is, it must resist sintering
which would lead to subsequent adhesion and penetration at the
metal-sand interface. To be used successfully as a mold or a
core into which or around which molten metal is cast, it also
must be highly permeable. This allows the escape of steam and
gases generated by action of the hot metal upon binders and
additives in the mold or core materials. Such a sand must have
sufficient strength under compression, shear, and tension to
retain its molded form not only in the green state at room
temperature, but also after drying and baking, and later at the
elevated temperatures induced by pouring. Finally, it must be
durable and resist deterioration and breakdown after repeated
use.
Core sand is washed and graded silica sand low in clay substance
and of a high permeability, suitable for core-making in ferrous
and nonferrous foundry practice. Furnace bottom sand is unwashed
and partially aggregated silica sand suitable for lining and
patching open hearth and electric steel furnaces which utilize an
acid process. The term fire sand is often employed but is
gradually going out of use. As for core sands, source materials
for this commodity are guartz sands and sandstones which occur
within reasonable shipping distances of steelmaking centers.
Chief production centers are in Illinois, Ohio, Michigan, West
Virginia, Pennsylvania, and New Jersey.
Ganister mix is a self-bonding, ramming mixture composed of
varying proportions of crushed guartzose rock or guartz pebble
and plastic fire clay, suitable for lining, patching, or daubing
hot metal vessels and certain types of furnaces. It is variously
referred to as Semi-silica or Cupola daub. As in molding sands,
there are two broad classes of materials used for this purpose.
One is a naturally-occuring mixture of quartz sand and refractory
clay, and the other is a prepared mixture of quartz in pebble,
granule, or sand sizes bonded by a clay to give it plasticity.
Naturally occuring ganister mix is exploited in two areas in
California and one in Illinois. The California material contains
roughly 75 percent quartz sand between 50 and 200 mesh; the
remaining portion is a refractory clay. However, the bulk of
this commodity is produced in the East and Midwest where the
foundry and steel business is centered. A large volume is
produced from pebbly phases of the Sharon conglomerate in Ohio.
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The Veria sandstone of Mississippian age is crushed and pellet-
ized for this purpose in Ohio. In Pennsylvania it is prepared
from the Chickies quartzite of Lower Cambrian age, although some
comes from a pebbly phase of the Oriskany. In Massachusetts, a
post-Carboniferous hydrothermal quartz is used and in Wisconsin,
production comes from the Pre-Cambrian Baraboo quartzite.
Naturally bonded molding sand is crude silica sand containing
sufficient indigenous clay to make it suitable for molding
ferrous or non-ferrous castings. Natural molding sands are
produced in New York, New Jersey, and Ohio. Coarse-grained
naturally bonded molding sand with a high permeability suitable
for steel castings is produced to some extent wherever the local
demand exists. Large tonnages are mined from the Connoquenessing
and Homewood sandstone members of the Pottsville formation in
Pennsylvania, the St. Peter sandstone in Illinois, and the
Dresbach sandstone of Upper Cambrian age in Wisconsin. Processed
molding sand is washed and graded quartz sand which, when
combined with appropriate bonding agents in the foundry, is
suitable for use for cores and molds in ferrous and nonferrous
foundries. The source materials which account for the major
tonnage of processed molding sand are primarily from the St.
Peter formation in Illinois and Missouri, the Oriskany quartzite
in Pennsylvania and West Virginia, the basal Pottsville in Ohio
and Pennsylvania, and the Tertiary sands in New Jersey.
Refractory pebble is clean graded silica in gravel sizes, low in
iron and alumina, used as a raw material for superduty acid
refractories. With few exceptions, bedded conglomerate and
terrace gravel furnish the bulk of the raw material. Silica
pebble from the Sharon conglomerate in Ohio and the Mansfield
formation in Indiana are utilized. Significant production comes
from a coarse phase of the Oriskany in Pennsylvania as well as
from deposits of Bryn Mawr gravel in Maryland. Potential
resources of conglomerate and terrace gravel of present marginal
quality occur in other areas of the United States. Other
quartzitic formations are currently utilized for superduty
refractory work. Notable production comes from the Baraboo
quartzite in Wisconsin, the Weisner quartzite in Alabama, and
from quartzite beds in the Oro Grande series of sediments in
California.
Runner sand is a crude coarse-grained silica sand, moderately
high in natural clay bond, used to line runners and dams on the
casting floor of blast furnaces. Runner sand is also used in the
casting of pig iron. The term Casthouse sand also is used in the
steel industry. Coal-washing sand is a washed and graded quartz
sand of constant specific gravity used in a flotation process for
cleaning anthracite and bituminous coal. Filter media consist of
washed and graded quartzose gravel and sand produced under close
textural control for removal of turbidity and bacteria from
municipal and industrial water supply systems.
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Hydraulic-fracturing sand is a sound, rounded, light-colored
quartz sand free of aggregated particles. It possesses high
uniformity in specified size ranges which, when immersed in a
suitable carrier and pumped under great pressure into a
formation, increases fluid production by generating greater
effective permeability. It is commonly referred to as Sandfrac
sand in the trade.
GYPSUM (SIC 1492)
Gypsum is a hydrated calcium sulfate (CaSOjJ»2HJ2O) generally found
as a sedimentary bed associated with limestone, dolomite, shale
or clay in strata deposited from early Paleozoic to recent ages.
Most deposits of gypsum and anhydrite (CaSOJt) are considered to
be chemical precipitates formed from saturated marine waters.
Deposits are found over thousands of square miles with
thicknesses approaching 549 meters (1800 feet), example the
Castle anhydrite of Texas and New Mexico. Field evidence
indicates that most deposits were originally anhydrite which was
subsequently converted by surface hydration to gypsum.
Commercial gypsum deposits are found in many states with the
leading producers being California, Iowa, Nevada, New York, Texas
and Michigan and lesser amounts being produced in Colorado, and
Oklahoma. Figure 5 shows the domestic locations of gypsum. The
ore is mined underground and from open pits with the latter being
the more general method because of lower costs. In 1958, 44 of
the 62 mining operations were open pits, while three of the
remainder were combinations of open pit and underground mines.
In quarrying operations, stripping of the overburden is usually
accomplished with drag lines or with tractors. Quarry drilling
methods vary with local conditions; blasting is accomplished with
low-speed, low density explosives. The fragmented ore is loaded
with power shovels onto trucks or rail cars for transport to the
processing facility. Generally, the primary crushing is done at
the quarry site. Second-stage crushing is usually accomplished
with gyratory units, and final crushing almost invariably by
hammermills. The common unit for grinding raw gypsum is the
air-swept roller mill. Ground gypsum is usually termed "land
plaster" in the industry, because either sacked or in bulk, it is
sold for agricultural purposes.
In recent years, a trend has started towards the beneficiation of
low-grade gypsum deposits where strategic location has made this
economically feasible. The heavy-media method has been
introduced in two Ohio facilities; screening and air separation
have been employed for improving purity in a limited number of
other operations. The tonnage of gypsum thus beneficiated is
still a small part of the total output.
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FIGURE 5
GYPSUM AND ASBESTOS OPERATIONS
GYPSUM
• ASBESTOS
FIGURE 6
LIGHTWEIGHT AGGREGATES, MICA AND SERICITE OPERATIONS
AAtA*
MICA AND SERICITE
PERLITE
PUMICE
VERMICULITE
33
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Most crushed gypsum is calcined to the hemi-hydrate stage by one
of six different methods - kettles, rotary calciners,
hoilow-flight screw conveyers, impact grinding and calcining
mills, autoclaves, and beehive ovens. The calcined gypsum is
used for various types of plasters, board and block, preformed
gypsum tile, partition tile, and roof plank. By far the largest
use of calcined gypsum (stucco) is for the manufacture of board
products. Gypsum board is a sandwich of gypsum between two
layers of specially prepared paper. It is manufactured in large
machines that mix stucco with water, foam and other ingredients
and then pour this mixture upon a moving, continuous sheet of
special heavy paper. Under "master rolls" the board is formed
with the bottom paper receiving the wet slurry and another
continually moving sheet of paper being placed on top. This
sandwich is then compacted, cut, and dried.
ASPHALTIC MINERALS
The bitumens are defined as mixtures of hydrocarbons of natural
or pyrogenous origin or combinations of both, frequently
accompanied by their derivatives, which may be gaseous, liquid,
semisolid or solid and which are completely soluble in carbon
disulfide. Oil shale and like materials which are mined for
their energy content are not covered by this subcategory.
The principal bituminous materials of commercial interest are:
(1) Native asphalts, solid or semisolid, associated with mineral
matter such as Trinidad Lake asphalt. Selenitza, Boeton and
Iraq asphalts.
(2) Native Asphaltites, such as gilsonite, grahamite and glance
pitch, conspicuous by their hardness, brittleness and
comparatively high softening point.
(3) Asphaltic bitumens obtained from non-asphaltic and asphaltic
crude petroleum by distillation, blowing with air and the
cracking of residual oils.
(4) Asphaltic pyrobitumens of which wurtzilite and elaterite are
of chief interest industrially as they depolymerize upon
heating, becoming fusible and soluble in contrast to their
original properties in these respects.
(5) Mineral waxes, such as ozokerite, characterized by their high
crystallizable paraffine content.
There are several large deposits of bituminous sand, sandstone
and limestone in various parts of the world but those of most
commercial importance are located in the United States and
Europe. Commercial deposits of bituminous limestone or sandstone
in the United States are found in Texas, Oklahoma, Louisiana,
Utah, Arkansas, California, and Alabama. The bitumen content in
these deposits range from 4 to 14 percent. Some of the sandstone
in California has a 15 percent content of bitumens, and a deposit
in Oklahoma contains as high as 18 percent. The Uvalde County,
34
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Texas deposit is a conglomerate containing 10 to 20 percent of
hard bitumen in limestone which must be mixed with a softer
petroleum bitumen and an aggregate to produce a satisfactory
paving mixture. Commercially, rock asphalt in this country is
used almost exclusively for the paving of streets and highways.
Rock asphalt is mined from open quarries by blasting and is
reduced to fines in a. series of crushers and then pulverized in
roller mills to the size of sand grains varying from 200 mesh to
inch in size.
Gilsonite, originally known as uintaite is found in the Uintah
basin in Utah and Colorado. Gilsonite is a hard, brittle, native
bitumen with a variable but high softening point. It occurs in
almost vertical fissures in rock varying in composition from
sandstone to shale. The veins vary in width from 0.025 to 6.7
meters (1 in to 22 ft) and in length from a few kilometers to as
much as U8 km (30 mi) . The depth varies from a few meters to
over 460 m (1500 ft) . Mining difficulties, such as the creation
of a very fine dust which in recent years resulted in two or
three serious explosions, and the finding of new uses for
gilsonite necessitated one company to supplement the conventional
pick- and- shovel method by the hydraulic system. However, on
some properties the mining is still done by hand labor,
compressed air picks, etc.
Grahamite occurs in many localities in the United States and in
various countries throughout the world but never in large
amounts . The original deposit was discovered in West Virginia
but has long been exhausted. Deposits in Oklahoma were exploited
to a great extent for years but little is now mined in commercial
quantities. The material differs from gilsonite and glance pitch
having a much higher specific gravity and fixed carbon, and does
not melt readily but intumesces on heating.
Glance pitch was first reported on the island of Barbados. The
material is intermediate between gilsonite and grahamite. It has
a specific gravity at 15.6°C of 1.09 to 1.15, a softening point
(ring and ball) of 135° to 20U<>C and fixed carbon of 20 to 30
percent.
Wurtzilite, sometimes referred to as elaterite, is one of the
asphaltic pyrobitumens and is distinguished by its hardness and
infusibility. It is found in Uintah County, Utah, in vertical
veins varying from 2.5 cm to 63.5 cm (1 in to 25 in) in width and
from a few hundred meters to 1.8 km (3 miles) in length. It is
used in the manufacture of paints, varnishes, as an extender in
hard rubber compounds, and various weatherproof ing and insulating
compounds .
Ozokerite is a solid waxlike bitumen the principal supply of
which is found in the Carpathian mountains in Galicia. A small
amount of it is also found in Rumania, Russia and the state of
35
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Utah. The hydrocarbons of which it is composed are solids,
resembling paraffin scale and resulted from evaporation and
decomposition of paraffinaceous petroleum. It occurs in either a
pure state or it may be mixed with sandstone or other mineral
matter. The material is mined by hand and selected to separate
any material containing extraneous matter. Ozokerite when
refined by heating to about 182°C (360°F), treated with sulfuric
acid, washed with alkali and filtered through fuller's earth is
called "ceresine."
ASBESTOS (SIC 1499)
Asbestos is a broad term that is applied to a number of fibrous
mineral silicates which are incombustible and which, by suitable
mechanical processing, can be separated into fibers of various
lengths and thicknesses. There are generally six varieties of
asbestos that are recognized: the finely fibrous form of
serpentine known as chrysotile and five members of the amphibole
group, i.e., amosite, anthophyllite, crocidolite, tremolite, and
actinolite. Chrysotile, which presently constitutes 93 percent
of current world production, has the empirical formula
3MgO. 2SiO_2.2H2!O and in the largest number of cases is derived
from deposits whose host rocks are ultrabasic in composition.
The bulk of chrysotile production comes from three principal
areas: the Eastern Townships of Quebec in Canada, the Bajenova
District in the Urals of USSR and from South Central Africa. The
ore-body of greatest known content in the United States is found
in the serpentine formation of Northern Vermont which is part of
the Appalachian belt extending into Quebec. Figure 5 shows the
domestic asbestos operations.
In North America the methods of asbestos mining are (1) open
quarries, (2) open pits with glory holes, (3) shrinkage stoping,
and (U) block caving; the tendency is toward more underground
mining. In guarrying, the present trend is to work high benches
up to 46 meters (150 feet) high and blast down 91,000 kkg
(100,000 tons) or more of rock at a shot. An interesting feature
of asbestos mining is that no wood may be used for any purpose
unless it is protected, because it is impossible to separate wood
fiber from asbestos in processing. Since the fiber recovery
averages only 5 to 6 percent of the rock mined, very large
tonnages must be handled. A capacity of 910 kkg/day (1,000
tons/day) is about the minimum for profitable operation.
Milling methods vary in detail, but they are nearly all identical
in principle. The objects of processing are to recover as much
of the original fiber as possible, free from dirt and adhering
rock; to expand and fluff up the fiber; to handle the ore as
gently as possible to minimize the reduction in fiber length by
attrition; and to grade the fibers into different length groups
best suited to use reguirements. The general method in use is
(1) coarse crushing in jaw or gyratory crushers, sometimes in two
36
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stages, to 3.8 to 5.1 cm (1-1/2 to 2 in); (2) drying to 1 percent
or less moisture in rotary or vertical inclined-plane driers; (3)
secondary crushing in short head cone crushers, gyratories, or
hammer mills; (H) screening, usually in flat shaking or gyratory
screens; (5) fine-crushing and fiberizing in stages, each stage
followed by screening, during which air suction above the screens
effects separation of the fiber from the rock; (6) collection of
the fiber in cyclone separators, which also remove the dust; (7)
grading of fibers in punched-plate trommel screens; (8) blending
of products to make specification grades; and (9) bagging for
shipment.
Fiberizing or opening up the bundles of fiber (step 5) is done in
a special type of beater or impact mill designed to free the
fiber from the rock and fluff up the fiber without reduction in
fiber length. The screening operations are perhaps the most
critical. The air in the exhaust hoods over each screen must be
so adjusted that only the properly fiberized material will be
lifted, leaving the rock and unopened fiber bundles for further
fiberizing. The air system uses 20 to 25 percent of the total
power consumed in a process facility.
WOLLASTONITE (SIC 1499)
Wollastonite is a naturally occurring, fibrous calcium silicate,
CaSiOj, which is found in metamorphic rocks in New York and
California, as well as several foreign locations. In the U.S.
the mineral is mined only in New York. The material is useful as
a ceramic raw material, as a filler for plastics and asphalt
products, as a filler and an extender for paints, and in welding
rod coatings. Due to its fibrous, non-combustible nature,
wollastonite is also being considered as a possible substitute
for asbestos in a number of product situations in which asbestos
is objectionable. Wollastonite ore is mined by underground room
and pillar methods and trucked to the processing facility. The
ore is crushed in three stages, screened, dried, purified of
garnet and other ferro-magnesium impurities via high-intensity
magnetic separation and then ground to the desired product size.
LIGHT WEIGHT AGGREGATE MINERALS (SIC 1499)
PERLITE
Perlite is a natural glassy rhyolitic rock that is essentially a
metastable amorphous aluminum silicate. It has an abundance of
spherical or convolute cracks which cause it to break into small
pearl-like masses usually less than a centimeter in diameter that
were formed by the rapid cooling of acidic lavas. Since natural
geological processes tend to work towards devitrification by
progressive recrystallization and loss of water, most useful
deposits of vitrified lava will be in recent lava flows of
Tertiary or Quarternary age. Thus, most of the significant
37
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deposits of perlite in the United States are found in the Western
states where active volcanism was recent enough that the perlite
deposits are preserved. At the present time, the most important
commercial deposit is in New Mexico.
Mining operations are open pit in locations chosen so that little
overburden removal is required and where topographic factors are
favorable for drainage and haulage of the crude ore. The ore is
mined by loosening the perlite with a ripper and picked up with a
pan scraper. In some cases fragmentation is accomplished by
blasting followed by a power shovel loading.
Milling proceeds in a jaw crusher and secondary roll crusher with
the normal screening operations. The sized ore, after removal of
fines which constitute roughly 25 percent of the process facility
feed, is dried in a rotary kiln to a residual moisture content
below 1 percent and sent to storage for subsequent shipment to
final processors.
The commercial uses of perlite depend upon the properties of
expanded perlite. When rapidly heated to 850-1100°C the glassy
nature of the natural material, coupled with the inclusion of
considerable moisture, results in the rapid evolution of steam
within the softened glass, causing an explosive expansion of the
individual fragments and producing a frothy mass having 15 to 20
times the bulk of original material. The term perlite is applied
to both the crude ore and the expanded product. Approximately 70
percent of consumption is as an aggregate for plaster, concrete
and for prefabricated insulating board wherein the perlite
inclusion results in an increase in the fireproof rating as well
as a significant reduction in weight. The fact that perlite is
relatively chemically inert, is relatively incompressible and has
a large surface area to volume ratio, makes it useful as an
important filter-aid material in the treatment of industrial
water and in the beverage, food and pharmaceutical processing
industry. Figure 6 locates the domestic perlite operations.
PUMICE
Pumice is a rhyolitic (the volcanic equivalent of a granite)
glassy rock of igneous origin in which expanded gas bubbles have
distended the magma to form a highly vesicular material.
Pumicite has the same origin, chemical composition and glassy
structure as pumice, but during formation the pumicite was blown
into small particles. Hence the distinction is largely one of
particle size in that pumicite has a particle size of less than 4
mm in diameter. Commercial usage has resulted in the generic
term pumice being applied to all of the various rocks of volcanic
ash origin. The chemical composition of pumice varies from 72
percent silica, 14 percent alumina and H percent combined
calcium, magnesium and iron oxides for the most acidic types to
approximately 45 percent silica, 16 percent alumina, and 30
38
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percent combined calcium, magnesium, and iron oxides for the most
basic types.
The distribution of pumice is world wide, but due to metamorphism
only those areas of relatively recent volcanism yield pumice
deposits of commercial importance. One great belt of significant
deposits borders the Pacific Ocean; the other trends generally
from the Mediterranean Sea to the Himalayas and thence to the
East Indies where it intersects the first belt. The largest
producers within the United States are found in California and
Idaho.
Mining operations are currently by open pit methods with the
overburden removed by standard earth moving equipment. Since
most commercial deposits of pumice are unconsolidated,
bulldozers, pan scrapers, draglines or power shovels can be used
without prior fragmentation. When pumice is used for railroad
ballast or road construction, the processing consists of simple
crushing and screening. Preparation for aggregate usually
follows a similar procedure but with somewhat more involved
sizing to conform to rigorous specifications. Occasionally, the
ore requires drying in rotary dryers either before or after
crushing. Pumice prepared for abrasive use requires additional
grinding followed by sizing via screening or air classification.
The domestic pumice operations are located in Figure 6.
VERMICULITE
Vermiculite is the generic name applied to a family of hydrated-
ferro-magnesium-aluminum silicates which, in the natural state
readily split like mica into their laminaie which are soft,
pliable, and inelastic. Vermiculite deposits are generally
associated with ultrabasic igneous host rocks such as pyroxenite
or serpentine from which the vermiculite seems to have been
formed by hydrothermal activity. Biotite and phlogopite mica,
which frequently occur with vermiculite, are considered to have a
similar origin. When heated rapidly, to temperatures of the
order of 1050-1100°C, vermiculite exfoliates by expanding at
right angles to the cleavage into long wormlike pieces with an
increase in bulk of from 8 to 12 times. The term vermiculite is
applied both to the unexpanded mineral and to the commercial
expanded product.
The bulk of domestically mined vermiculite comes either from the
extensive deposit at Libby, Montana or from the group of deposits
near Enoree, South Carolina. Mining operations are by open pit
with removal of alluvial overburden accomplished by
tractor-driven scrapers. The ore can be dug directly by power
shovel or dragline excavator. Dikes or barren host rock require
fragmentation by drilling and blasting prior to removal. Ore
beneficiation is accomplished by wet processing operations using
hammer mills, rod mills, rake classifiers, froth flotation.
39
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cyclones, and screens. Centrifuges and rotary driers are used to
remove excess moisture following beneficiation. Exfoliation is
carried out in vertical furnaces wherein the crude, sized
vermiculite is top fed and maintained at temperatures from
900-1100°C for a to 8 seconds. The expanded product is removed
by suction fans and passed through a classifier system to collect
the product and to remove excessive fines. Figure 6 locates the
domestic vermiculite operations.
MICA (SIC 1199)
Mica is a group name for a number of complex hydrous potassium
aluminum silicate minerals differing in chemical compositions and
in physical properties, but which are all characterized by
excellent basal cleavage that facilitates splitting into thin,
tough, flexible, elastic sheets. There are four principal types
of mica named for the most common mineral in each type -
muscovite, phlogopite, biotite and lepidolite with muscovite
(potassium mica) being commercially the most important. Mica for
commercial reasons is broken down into two broad classifications:
sheet mica which consists of relatively flat sheets occurring in
natural books or runs, and flake and scrap mica which includes
all other forms.
Muscovite sheet mica is recovered only from pegmatite deposits
where books or runs of mica occur sporadically as crystals which
are approximately tabular hexagons ranging from a few centimeters
to several meters in maximum dimension. Mica generally occurs as
flakes of small particle size in many rocks. In addition, the
mica content of some schists and kaolins is sufficiently high to
justify recovery as scrap mica.
Domestic mica mining has been confined mainly to pegmatites in a
few well-defined areas of the country. The largest area extends
from central Virginia southward through western North and South
Carolina and east-central Alabama. A second area lies
discontinuously in the New England States, where New Hampshire,
Connecticut, and Maine each possess mica bearing pegmatites. A
third region comprises districts in the Black Hills of South
Dakota and in Colorado, Idaho, and New Mexico. Additional
sources of flake mica have been made available through the
development of technology to extract small particle mica from
schists and other host rocks. Deposits containing such mica are
available throughout the U.S.
Sheet mica mines are usually small-scale operations. Open pit
mining is used when economically feasible, but many mica bearing
pegmatites are mined by underground methods. During mining, care
must be taken to avoid drilling through good mica crystals. Only
a few holes are shot at one time to avoid the destruction of the
available mica sheet. Presently there is no significant quantity
of sheet mica mined in the U.S. Larger scale guarrying methods
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are used to develop deposits for the extraction of
small-particle-size mica and other co-product minerals.
Flake mica that is recovered from pegmatites, schist, or other
rock is obtained by crushing and screening the host rock and
additional beneficiation by flotation methods in order to remove
mica and other co-product minerals. Then it is fed to an
oil-fired rotary dryer. The dryer discharge goes to a screen
from which the fines are either wasted or saved for further
recovery.
Raw material for ground mica is obtained from sheet mica
processing operations, from crushing and processing of schists,
or as a co-product of kaolin or feldspar production. Buhr mills,
rodmills, or high-speed hammer mills have been used for
dry-grinding mica. An air separator returns any oversize
material for additional grinding and discharges the fines to a
screening operation. The various sized fractions are bagged for
marketing. The ground mica yield from beneficiated scrap runs 95
to 96 percent.
"Micronized" mica is produced in a special type of dry-grinding
machine, called a Micronizer. This ultrafine material is
produced in a disintegrator that has no moving parts but uses
jets of high-pressure superheated steam or air to reduce the mica
to micron sizes. This type of mica is produced in particle size
ranges of 10 to 20 microns and 5 to 10 microns.
Wet-ground mica is produced in chaser-type mills to preserve the
sheen or luster of the mica. This consists of cylindrical steel
tank that is lined with wooden blocks laid with the end grain up.
Wooden rollers are generally used, which revolve at a slow rate
of 15 to 30 revolutions per minute. Scrap goes to the mill,
where water is added slowly to form a thick paste. When the bulk
of the mica has been ground to the desired size, the charge is
washed from the process facility into settling bins where gritty
impurities sink. The ground mica overflows to a settling tank
and is dewatered by centrifuging and steam drying. The final
product is obtained by screening on enclosed multiple-deck
vibrating screens, stored and then bagged for shipment. Figure 6
locates the domestic mica and sericite operations.
BARITE (SIC 1472 S 3295)
Barite, which is also called barytes, tiff, cawk or heavy spar,
is almost pure barium sulfate and is the chief source of barium
and its compounds. Barite deposits are widely distributed
throughout the world, and can be classified into three main
types: (a) vein and cavity filling deposits; (b) bedded deposits;
and (c) residual deposits.
41
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(a) Vein and cavity-filling deposits are those in which the
barite and associated minerals occur along fault lines,
bedding planes, breccia zones and solution channels. Barite
deposits in the Mountain Pass district of California are of
this variety.
(b) Bedded deposits are those in which the barite is restricted
to certain beds or a seguence of beds in sedimentary rocks.
The major commercial deposits in Arkansas, Missouri,
California and Nevada are bedded deposits.
(c) Residual deposits occur in unconsolidated material that are
formed by the weathering of pre-existing deposits. Such
deposits are abundant in Missouri, Tennessee, Georgia,
Virginia and Alabama where the barite is commonly found in a
residuum of limestone and dolomites.
Mining methods used in the barite industry vary with the type and
size of deposit and type of product made. Figure 7 displays the
barite processing facilities in the United States. Residual
barite in clay is dug with power shovels from open pits
(Missouri, Tennessee, Georgia). Stripping is practiced when
overburden is heavy, and the barite is then removed by dragline,
tractors, scrapers, or power shovel. Overburden in Missouri is
rarely over 0.6 or 0.9 meters (2 or 3 feet), but in Georgia it
may range from 3 to 15 meters (10 to 50 feet). Hydraulic mining
has been used at times in Georgia where overburden has been
heavy, where troublesome limestone pinnacles have been
encountered, or where tailing ponds have been reclaimed. Barite
veins or beds are mined underground (Nevada, Tennessee, and
Arkansas). Massive barite is blasted from open guarries with
little or no subseguent sorting or beneficiation (Nevada).
Methods used in the beneficiation of barite depend both on the
nature of the ore and on the type of product to be made. For the
largest use, well-drilling mud, the only requirements are small
particle size (325 mesh) , chemical inactivity, and high specific
gravity. White color is not essential, and purity is not
important in many cases.
The essential features of the milling of residual barite in clay
(Missouri, Georgia, and Tennessee, in part) include washing to
remove the clay, hand picking to save lump barite, jigging to
separate coarse concentrates, and tabling to recover fine con-
centrates. Further refinements may include magnetic separation
to remove iron from concentrate fines and froth flotation to save
the very finest barite. In Missouri, where the ore is so soft
that crushing is unnecessary and individual deposits tend to be
small, simple and inexpensive facilities that can be easily
dismantled and moved are common. Missouri mills may consist
essentially of only a double log washer, trommel, and jigs, but
there are a few large mills. Hard, vein barite is usually pure
-------
FIGURE 7
BARITE PROCESSING PLANTS
LO
Data From: Industrial and Chemical Mineral
Chart - p. 184
The National Atlas of the USA
USGS - 1970
-------
enough to be shipped without beneficiation except hand sorting.
In Georgia, the ore is hard and usually must be crushed to free
the barite from the gangue; facilities tend to be large with
several stages of crushing, screening, jigging and tabling.
The development of froth flotation methods have made deposits,
such as those of Arkansas and Georgia, commercially valuable and
have greatly increased recovery possibilities from other
deposits. The Arkansas ore is particularly difficult to treat,
since the barite is finely divided and so intimately mixed with
the impurities that grinding to 325 mesh is necessary for
complete liberation of the component minerals. The ground ore is
then treated by froth flotation. Concentrates are filtered and
dried in rotary kilns at temperatures high enough to destroy
organic reagents that might interfere with use in drilling muds.
In Georgia, flotation is being used to recover barite fines from
washer tailings..
The methods used in grinding barite depend upon the nature of the
product to be ground and upon the use for which the ground barite
is to be sold. If white color is not important, as for
well-drilling mud and off-color filler uses, iron grinding
surfaces may be used. Where the color is naturally a good white
and bleaching is not required, grinding is done with iron-free
grinding surfaces, such as a dry pebble mill in closed circuit
with an air separator.
The principal use of barite in the United States is as a
weighting agent for drilling muds used in the oil industry. In
addition, ground barite is used in the manufacture of glass and
as a heavy filler in a number of products where additional weight
is desirable.
FLUORSPAR (SIC 1U73)
Fluorine is derived from the mineral fluorite, commonly known as
fluorspar. Steadily increasing quantities are required in steel
production where fluorite is useful as a slag thinner; in
aluminum production, where cryolite is necessary to dissolve
alumina for the electrolytic cells; and in ceramics, where
fluorite is a flux and opacifier. Fluorine demand is strong for
an important group of fluorocarbon chemicals which are formulated
into refrigerants, plastics, solvents, aerosols, and many other
industrial products.
In the Illinois-Kentucky district fluorspar occurs as veins in
limestone, shale, and sandstone along faults ranging in thickness
from a mere film to a width of more than 9 meters (30 feet) and
in extensive flat-lying replacement-type deposits in limestone.
Residual deposits, resulting from weathering of fluorite-bearing
veins, are also fairly common in the district and often indicate
the presence of vein deposits at greater depth.
-------
In the western States, fluorspar occurs under a wide variety of
conditions such as fillings in fractures and shear zones forming
more or less well-defined veins and as replacements in the
country rock. Much occurs in igneous formations. Figure 8
depicts the locations of barite processing facilities in the
United States.
Mining is done by shafts, drifts, and open cuts with the mines
ranging in size from small operations using mostly hand-operated
equipment to large fully mechanized mines. Top slicing, cut-and-
fill, shrinkage, and open stoping are among the mining methods
commonly used. Bedded deposits are usually worked by a room-and-
pillar system. Some of the large mines are extensively
mechanized, using diesel-powered hauling and loading equipment.
The crude ore requires beneficiation to yield a finished product.
Processing techniques range from rather simple methods, such as
hand sorting, washing, screening and gravity separation by jigs
and tables, to sink-float and froth-flotation processes. The
flotation process permits.recovery of the lead, zinc, and barite
minerals often associated with the fluorspar ores. Flotation is
used where a product of fine particle size is desired, such as
ceramic- and acid-grade fluorspar. The heavy-medium or sink-
float process is usually employed where a coarse product, such as
metallurgical-grade gravel is desired.
SALINES FROM EFINF. LAKES (SIC 1474)
A number of the potash, soda and borate minerals are produced
from the brines of Western lakes that have evaporated over long
periods of time to a high concentration of minerals. The
significant commercial exploitation of these lake brines is at
Searles Lake in California and the Great Salt Lake in Utah. Two
facilities are operated at Searles Lake that employ a complex
series of evaporation steps to recover minerals and, in some
instances, produce other derived products such as bromine and
boric acid. The process sequence is called the "Trona Process",
which should not be confused with trona ore (natural sodium
carbonate) mining that takes place in Sweetwater County, Wyoming.
One facility utilizes an evaporative process at the Great Salt
Lake to produce sodium sulfate, salt, potassium sulfate, and
bittern liquors. Figure 9 shows the potash deposits in the
United States including brine recovery. Figure 10 shows all of
the borate deposits. Figure 11 shows the calcium and magnesium
brine locations.
BORATES (SIC 1474)
While boron is not an extremely rare element, few commercially
attractive deposits of boron minerals are known. It is estimated
that about half of the commercial world boron reserves, estimated
at about 65 million kkg (72 million tons), are in southern
45
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FIGURE 8
FLUORSPAR PROCESSING PLANTS
From Industrial and Chemical Minerals chart-pg.184
The National Atlas of The USA
USGS-1970
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FIGURE 9
POTASH DEPOSITS
»-Mines
• -Wells
-Surface brim-
From Salines chart-pg.181
The National Atlas of The USA
USGS-1970
FIGURE 10
BORATE OPERATIONS
From Saline1; rh.nt-m.181
The National Ail.r. of The USA
USGS-1970
47
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FIGURE 11
LITHIUM, CALCIUM AND MAGNESIUM
• Lithium
• Cal d urn conipniuuK (Hr1 ne)
* Magnesium comp.(Brine)
From Salines Chart-pg.181
The National Atlas of The USA
USGS-1970
FIGURE 12
ROCK SALT MINES AND WELLS
From S,ilinc r.h.irt-pq.181
The Njtion.il /Ulas of The USA.
USfiS-19/0
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California as bedded deposits of borax (sodium borate) and
colemanite (calcium borate), or occur as solutions of boron
minerals in Searles Lake brines. Figure 10 shows the location of
the United States operations. The United States is the largest
producer of boron, supplying 71 percent of the world demand in
1968, and also the largest consumer, requiring about 36 percent
of the world output.
Many minerals contain boron, but only a few are commercially
valuable as a source of boron. The principal boron minerals are
borax (tincal) , Na.2B4p7«10H.2O; kernite (rasorite) , NalBOpV^tHttO;
colemanite (borocalcite) , Ca_2B6OJM«5H2O; ulexite
(boronatrocalcite) , CaNaBj3O9«8H2O; priceite (pandermite) ,
5CaO«6B203«9H20; boracite (stassfurtite) , Mg7Cl2B16O.30; and
sassolite (natural boric acid), H_3BOJ. The sodium borate
minerals borax and kernite (rasorite) constitute the bulk of
production in the United States. A small quantity of colemanite
and ulexite is also mined.
The borate deposit in the Kramer district of California is a
large, irregular mass of bedded crystalline sodium borate ranging
from 24 to about 305 meters (80 to 1,000 feet) in thickness.
Borax, locally called tincal, and kernite are the principal
minerals. Shale beds containing colemanite and ulexite lie
directly over and under the sodium borate body.
One company mines the ore by open-pit methods. It is blended and
crushed to produce a minus 1.9 centimeters (3/4 inch) feed of
nearly constant boric oxide (B.2O_3) content. Weak borax liquor
from the refinery is mixed with the crushed ore and heated nearly
to boiling point in steam-jacketed tanks to dissolve the borax.
The concentrated borax liquor is processed in a series of
thickeners, filtered and pumped to vacuum crystallizers. One of
the crystallizers produces borax pentahydrate, and the other
produces borax decahydrate.
Sodium borates are also extracted from Searles Lake brines by a
company whose primary products are soda ash, salt cake, and
potash. Searles Lake is a dry lake covering about 88 square km
(34 square miles) in San Bernardino County, California. Brines
pumped from beneath the crystallized surface of the lake are
processed by carbonation, evaporation, and crystallization
procedures, producing an array of products including boron
compounds.
Ferroboron is a boron iron alloy containing 0.2 to 24 percent
boron, and is marketed in various grain sizes. Boric oxide is a
hard, brittle, colorless solid resembling glass. It is marketed
in powder or granular forms.
49
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Borax (Naj2B4Q7»10H2O) , the most commonly known boron compound, is
normally marketed with 99.5 percent purity. It is also available
in technical, U.S.P., and special-quality grades. In addition to
the decahydrate, the pentahydrate (Na2BUO_7«5H2O) and anhydrous
forms are sold. The various grades are available in crystalline,
granular, or powder forms. Boric acid (R3BQ3) is a colorless,
odorless, crystalline solid sold in technical, U.S.P., and
special quality grades. It is available in crystalline,
granular, or powder forms.
Boron compounds are mined in a remote desert area where tailings
and waste dumps do not encroach on residential, industrial, or
farm land. Atmospheric pollution is not a problem, although some
processing odors and dust are produced.
POTASH (SIC 147U)
The term "potash" was derived from the residues, pot ashes,
originally obtained by evaporating in iron pots solutions leached
from wood ashes. The present worldwide meaning of potash is
twofold. When used as a noun, it represents K20 equivalent, and
when used as an adjective, it means potassium compounds or
potassium-bearing materials. Sylvinite, the major ore for
producing potash, comes from underground mines in New Mexico,
Canada and Europe, and is a mineralogical mixture of sylvite
(KC1) and halite (NaCl) .
Domestic sources for potassium are of two types: brines and
bedded deposits. Currently 84 percent of domestic production
comes from the bedded deposits in southeastern New Mexico near
Carlsbad. The higher grade (20 to 25 percent K2O) commercial ore
in this area is nearing depletion and most of the seven producing
firms are estimated to have only a 6- to 10-year supply. U. S.
production reached a peak output in 1966 and has since declined.
Figure 9 shows the locations of the domestic deposits.
In the conventional shaft-type mining operations, large con-
tinuous mining machines are used in both the New Mexico and
Canadian mines. Poom-and-pillar mining methods are used in New
Mexico with a first-run extraction of about 65 percent while in
the deeper Canadian mines the first-run extraction is in the
order of 35 percent. On the second pass in the New Mexico mines
at least 55 percent of the remining potash is recovered by
"pillar robbing" for a total extraction of about 83 percent of
ore body. As much as 90 percent recovery has been claimed for
some operations. Pillar robbing is not practiced in Canada and
because of the greater mine depth it is not likely to be with
present technology.
50
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Two basic methods of ore treatment, flotation and fractional
crystallization, are used both in the Carlsbad area and in Canada
to recover sylvite from the ore. In general, the crushed ore is
mixed with a brine saturated with both sodium and potassium
chlorides and deslimed to remove most of the clay impurities.
The pulp is conditioned with an amine flotation reagent and sent
to flotation cells where the sylvite is separated from the
halite, the principal impurity. The halite fraction is repulped
and pumped to the tailings areas; the sylvite concentrate is
dried, sized, and shipped or sent to storage.
Fractional crystallization is based on the specific difference in
the solubility-temperature relationships of sodium chloride and
potassium chloride in saturated solution. Crushed ore is mixed
with hot, saturated sodium chloride brine, which selectively
dissolves the potassium chloride. The brine is then cooled
causing the potassium chloride to crystallize as a 99 percent
pure product.
Langbeinite is separated from halite, its principal impurity, by
the selective solution of the halite. The flotation process is
also used to separate langbeinite from sylvite.
Potassium compounds are recovered from brines, including brines
from solution mining, by evaporation and fractional
crystallization. The sodium salts in Searles Lake brines are
separated in triple-effect evaporators, leaving a hot liguor rich
in potash and borax. Rapid cooling of the sodium-free solution
under vacuum causes the potassium salts to crystallize. The
crystals of potassium salts are then removed by settling and
centrif uging.
About 8 t percent of the domestic potash is produced in a
square km (55-square mile) area 21 km (15 miles) east of
Carlsbad, New Mexico. There are eight refineries in this
district, each requiring large tailing disposal areas consisting
largely of sodium chloride salt; consequently, areas covered with
this waste are incapable of supporting any plant growth. The
operation near Moab, Utah, is similarly located, but extreme care
is exercised to prevent pollution of the nearby Colorado River.
The brine operation in Utah requires large evaporating pans
covering many acres of the land surface. The process involved
here involves evaporation of Great Salt Lake waters first to
recover common salt (NaCl) and then potassium sulfate. Residual
brines, containing mostly magnesium and lithium salts are
returned to the lake.
51
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TRONA (SIC 1474)
Trona (Na2CC31SlaHC03»2H2O) is the most common sodium carbonate
mineral found in nature. It crystallizes when carbon dioxide gas
is bubbled through solutions having a concentration of sodium
carbonate greater than 9 percent. Carbonation of less
concentrated solutions precipitates sodium bicarbonate. The
largest known deposit of relatively pure trona in the United
States was discovered in southwest Wyoming in 1938 while drilling
for oil near Green River. The deposit is relatively free of
chlorides and sulfates and contains 5 to 10 percent insoluble
matter and constitutes the only mineable quantity of this
material. It is also the world's largest natural source of
sodium carbonate (soda ash).,
Trona is a sedimentary deposit precipitated in the bottom of the
ancient Eocene Lake Gosiute. Subsequent deposits of oil shale,
siltstone and sandstone covered the trona, and the beds that are
mined 240 to 460 meters (800 to 1500 feet) below the surface.
Approximately 25 different trcna-bearing beds lie buried at
depths of 130 to 1100 meters (440 to 3500 feet).
Trona ore mining is carried out near Green River, Wyoming by four
corporations. Only three have soda ash refining facilities on
site at the present time. The increasing industrial use of soda
ash, together with the phasing out of obsolete and controversial
synthetic soda ash facilities in the East has caused a great
spurt of growth in the trona ore industry from the early 1960's.
The mineable resources of trona in this area have been estimated
to be 45 billion kkg (50 billion short tons).
SODIUM SULFATE
Natural sodium sulfate is derived from the brines of Searles Lake
in California, certain underground brines in Texas, and dry lake
brines in Wyoming. Sodium sulfate is also derived as a
by-product from rayon production, which requires that caustic
solutions used in processing cellulose fiber be neutralized with
sulfuric acid. Other sources of by-product sodium sulfate
include the chemical processes that produce hydrochloric acid,
cellophane, boric acid, lithium carbonate, phenol, and formic
acid.
The natural sodium sulfate is produced by six facilities in
California, Utah, and Texas. Three facilities in California
produce 74 percent of the natural product.
ROCK SALT (SIC 1476)
Sodium chloride, or salt, is the chief source of all forms of
sodium. Salt is produced on a large scale from bedded and
dome-type underground deposits and by evaporating lake and sea
52
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brines. Increasing quantities of two commercially important
sodium compounds, sodium carbonate (soda ash) and sodium sulfate
(salt cake), are produced from natural deposits of these
compounds, although salt is still the main source of both.
Bedded salt deposits are formed when a body of sea water becomes
isolated from the circulating ocean currents by a reef, sandbar,
or other means, and under suitably dry and warm climatic
conditions evaporation proceeds until the salts are partially or
entirely deposited. With continuous or periodic influx of sea
water to replace evaporation, large deposits of salt have been
built up in some instances to several thousand meters in
thickness. Deposits of this type have also been called lagoonal.
During the Permian geologic age two famous salt deposits of the
lagoonal type were laid down, one in northern Germany and the
other in eastern New Mexico. A second large bedded deposit in
the United States is the Silurian salt deposit, which underlies
Michigan, New York, Pennsylvania, Ohio, and West Virginia. it
was formed in much the same manner as the Permian beds by the
evaporation of a large inland sea which became separated from the
ocean and gradually evaporated.
Playa deposits were formed by the leaching of surrounding
sediments with water, which subsequently drained into a
landlocked area and evaporated, leaving the salts. The
composition of the brines and salt beds of these deposits
generally does not resemble that of sea water; playa deposits of
California and Nevada also contain sodium carbonate, sodium
sulfate, potash and boron.
Salt domes are large vertical structures of salt, resulting from
the deformation of deeply buried salt beds by great pressure.
The plastic nature of halite under high temperature and pressure
and its low density, compared with that of the surrounding rock,
permited deeply buried sedimentary deposits to be forced upward
through zones of weakness in the overlying rocks, forming
vertical columns or domes of salt extending several thousand
meters in height and cross section. If the bedded deposit at the
base of the dome is sufficiently large, the salt columns may rise
to the surface. There are reportedly 300 salt domes in the Gulf
coast area from Alabama to Mexico.
Rock salt is mined on a large scale in Michigan, Texas, New York,
Louisiana, Ohio, Utah, New Mexico, and Kansas, with
room-and-pillar the principal mining method. Rooms vary in size
depending on the thickness of the seam and other factors. In one
mine an undercutter cuts a slot 3 meters (10 feet) deep at the
base of the wall, which is then drilled and blasted. About 0.2
kg of dynamite per kkg of salt is required. The broken salt is
transported by various mechanical means such as loaders, trucks,
and belt conveyors to the underground crushing area. The salt
may be processed through a number of crushing and screening
53
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stages prior to being hoisted to the surface where the final
sizing and preparation for shipment or further use is carried
out.
About 57 percent of the U.S. salt output is produced by
introducing water into a cavity in the salt deposits and removing
the brine. This procedure is relatively simple and has
particular advantage when the salt is to be used as a brine as,
for example, in chemical uses such as soda ash and caustic
manufacture. Holes are drilled through the overburden into the
deposit and cased with iron pipe. Water is introduced into the
deposit through a smaller pipe inside the casing. A nearly
saturated brine is formed in the cavity at the foot of the pipe.
This brine is pumped or airlifted through the annular space
between the pipes. Figure 12 shows the locations of current rock
salt operations in the United States.
PHOSPHATE ROCK (SIC 1475)
The term "phosphate rock" includes phosphatized limestones,
sandstones, shales, and igneous rocks which do not have a
definite chemical composition. The major phosphorus minerals of
most phosphate rock are in the apatite group and can be
represented by the generalized formula Ca5_(POj»).3 - (F, Cl, OH).
'The (F, Cl, OH) radical may be all fluorine, chlorine, or
hydroxyl ions or any combination thereof. The (POJI) radical can
be partly replaced by small quantities of VOjt, AsOj*, SiOjJl, SOU,
and CO3. Also, small quantities of calcium may be replaced by
elements such as magnesium, manganese, strontium, lead, sodium,
uranium, cerium, and yttrium. The major impurities include iron
as limonite, clay, aluminum, fluorine, and silica as quartz sand.
Phosphate rock occurs as nodular phosphates, residual weathered
phosphatic limestones, vein phosphates, and consolidated and
unconsolidated phosphatic sediments. The best known of the
apatite minerals, fluorapatite is widely distributed. Relatively
small deposits of fluorapatite occur in many parts of the world.
The domestic deposits that are currently being exploited are
indicated in Figure 13.
Phosphate ore is mined by open pit methods in all four producing
areas: Florida, North Carolina, Tennessee, and the Western
States. In the Florida land-pebble deposits, the overburden is
stripped and the ore mined by large electric dragline excavators
equipped with buckets, with capacities up to 123 cubic meters (U9
cubic yards). The ore is slurried and pumped to the washing
facility, in some instances several miles from the mine. In the
Tennessee field and the open pit mines in the western field, the
ore is mined by smaller dragline excavators, scrapers or shovels
and trucked to the facilities. In North Carolina a 180 cubic
meter (72 cubic yard) dragline is used for stripping, and the ore
is then hydraulically transported to the washer.
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FIGURE 13
PHOSPHATE MINING AND PROCESSING LOCATIONS
From Industrial and Chemical
Minerals chart-pg.184.
The National Atlas of The USA
USGS-1970
FIGURE 14
SULFUR DEPOSITS
From Industrial and Chemical Minerals chart-
p.|.1R4
The flit! .nal Atlas of The USA
uses-rim
55
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Washing is accomplished by sizing screens, log washers, various
types of classifiers, and mills to disintegrate the large clay
balls. The fine slime, usually minus 150 mesh, is discarded. In
the Florida land-pebble field, the plus 14 mesh material is dried
amd marketed as high-grade rock or sometimes blended with the
fine granular material (minus 1U, plus 150 mesh) that has been
treated in flotation cells, spirals, cones or tables. Losses in
washing and flotation operations, which range from UO percent of
the phosphorus in the Florida operations to more than 50 percent
in some Tennessee areas, occur in the form of slimes containing U
to 6 percent solids. These slimes are discharged into settling
ponds, where initial settling occurs, and substantial quantities
of relatively clear water is returned to the mining and washing
operations.
Some of the western field phosphate rock production is of
suitable grade as it comes from the mine. Siliceous phosphate
ore and mixtures of phosphate rock and clay minerals are amenable
to benefication, and in 1968 three companies in the western field
were beneficiating part of their production. Two flotation
facilities and several washing facilities were in operation in
1968.
Several environmental problems are associated with the phosphorus
and phosphate industry. In the southeastern states mining and
processing of phosphate rock is located close to developed and
expanding urban areas. In the Florida land-pebble district the
phosphate matrix (ore) underlies 1.2 to 18 meters (4 to 60 feet)
of overburden consisting mostly of sand and clay requiring the
use of large draglines to remove the overburden. The major
mining companies, together and individually, have embarked upon a
continuing program of reclamation of mined-out areas and are
planning mining operations to provide easier and more economical
methods of reclamation. Many thousands of acres of land have
been reclaimed since the program started.
The Florida phosphate rock washing operations, because of the
nature of the material, produces large quantities of a slurry of
verv fine clay and phosphate minerals called slimes. This is a
waste product and must be contained in slime ponds that cover
large areas since many years of settling are required before
these pond areas can be reclaimed. Much research effort has been
expended by both government and industry to solve this problem
which is not only an environmental one but also one of
conservation since about 33 percent of the phosphorus values are
wasted. Some progress has been made and old slime ponds are now
being reclaimed for recreational, agricultural, and other uses.
The greatest problems of this nature exist in central Florida but
similar situations prevail in northern Florida and Tennessee.
56
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SULFUR (SIC 1477)
Elemental sulfur is found in many localities generally in
solfataras and gypsum-type deposits. By far, most of the world's
supply of sulfur comes from the gypsum-type deposits where it
occurs as either crystalline or amorphous sulfur in sedimentary
rocks in close association with gypsum and limestone. The origin
of such deposits has been variously attributed to geochemical
processes involving the reduction of calcium sulfate by carbon or
methane followed by oxygenation of the resulting hydrogen
sulfide; or to biochemical processes involving the reduction of
sulfate to sulfide by various microorganisms.
The major domestic sources of sulfur are associated with the Gulf
Coast salt domes which characteristically are circular or oval in
cross-section with the sulfur-bearing cap rock occurring at
depths of less than 900 meters (3000 feet). The diameter of the
domes may vary from 0.8 to 8 km (0.5 to 5 miles) with a dry,
compact, coarsely crystalline salt column below the cap rock.
Most of the elemental sulfur is found in the limestone or
carbonate zone of the cap rock with a horizon which may vary from
nearly zero to several hundred meters in thickness having sulfur
content which.may range from traces to more than 40 percent.
The sulfur formations in West Texas are in porous zones of gently
dipping dolomitic limestone, silty shale, anhydride and gypsum.
The sulfur deposits are low grade and the layers that contain
sulfur are thin. Depths of the sulfur deposits range from 200 to
460 meters (700 to 1,500 feet). Surface exposures of sulfur in
porous gypsum and anhydrite are distributed over a rectangular
area about 64 km long and 48 km wide (40 miles long and 30 miles
wide) in both Culberson and Reeves counties.
Mining of sulfur is accomplished by the Frasch or hot water
process. In the Frasch process, the sulfur is melted underground
by pumping super heated water in to the formation. The molten
sulfur is then raised to the surface through the drill pipe and
stored in liquid form in steam-heated tanks. In most
installations, the liguid sulfur is pumped directly into heated
and insulated ships or barges that can transport the sulfur in
liguid form. Approximately 15 percent of the total sulfur
produced in the U.S. is metered and pumped to storage vats for
cooling and solidifying before it is sold in dry form.
Sulfur has widespread use in the manufacturing of fertilizers,
paper, rubber, petroleum products, chemicals, plastics, steel,
paints and other commodities, with the fertilizer industry
consuming approximately 50 percent of the total U.S. sulfur
production. The locations of the United States sulfur deposits
are shown in Figure 14.
57
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MINERAL PIGMENTS
The mineral pigments consist of three general groups:
(1) Those consisting mostly of iron oxides such as hematite and
limonite.
(2) Those containing large amounts of clay or noncoloring matter,
such as ocher, sienna, umber and colored shales.
(3) Those whose color is not due to iron oxide such as Vandyke
brown, graphite and terre-verte.
Since the coloring power of the natural yellow, red, and brown
mineral pigments is due principally to the content and condition
of iron oxide, the occurrence of mineral pigments in many
instances is closely allied to that of the iron ores. Pigment
materials and iron ores often are mined in the same localities,
and iron ores are used at times for mineral pigments of the red
and brown varieties. The iron oxides are almost universally
distributed.
Replacement or precipitation deposits are the principal sources
of limonite and ocherous minerals. They have been deposited in
cavities by ground waters charged with iron salts removed from
the weathering of impure limestone, sandstones, and shales,
especially when pyrite was an accessory mineral. The most
important deposits are found usually in the fractured and faulted
zones of rocks of all ages, including the Cambrian quartzites of
Georgia, the Paleozoic limestones and quartzites of Pennsylvania,
and the unconsolidated Tertiary clays, sands, manganese ores, and
lignites of Vermont.
In Virginia, deposits of residual limonite occur in two belts,
one extending along the west slope of the Blue Ridge from Warren
to Roanoke County and the other along the east side of the New
River-Cripple Creek district, Pulaski County, and near the
boundary of Wythe and Carroll Counties. The latter deposits are
associated with Cambrian quartzites. The deposits in Pulaski
County have produced ochers of high iron content somewhat similar
in analyses and properties to the Georgia ocher.
The chief production of earth pigments in the United States in
recent years has come from Pennsylvania, Virginia, Illinois,
Minnesota, Georgia, California, and New York. In Pennsylvania,
ocher is mined both by opencut methods and shafts, and in Georgia
by opencut methods. In most deposits the pockety character of
the ore and the uncertain market for the product do not justify
elaborate equipment.
The soft, claylike pigments are treated by comparatively simple
washing processes, followed by dehydration and pulverization.
Log washers and blungers are used for dispersion; trough, cone,
and bowl classifiers separate the sand from the fine suspension.
58
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A portion of the water is removed in settling tanks and the
remainder is extracted by filter presses and rotary driers.
Hammer type pulverizers reduce the pigment to powder for packing
and shipment and a final air separation may be interposed for the
better grades.
LITHIUM MINERALS (SIC 1479)
Spodumene, petalite, lepidolite, and ainblygonite are the minerals
from which lithium is derived. Brines are another source of
lithium. Domestic spodumene is recovered by mechanical mining
and milling processes, and either an acid or an alkali method is
used to extract lithium compounds from the spodumene ore.
Lithium minerals have been mined from pegmatite depostis by open
pit and underground methods. Other minerals such as beryl,
columbite, feldspar, mica, pollucite, quartz, and tantalite are
often extracted and recovered as coproducts in the mining
process.
In North Carolina spodumene is recovered from the pegmatite ore
by crushing, screening, grinding, and flotation, and lithium
compounds are recovered from spodumene concentrates by an acid or
an alkali treatment. In the method employing acid, spodumene is
changed from the alpha form to the beta form by calcining at
982°C (1,800°F). Next it is added to sulfuric acid and the
mixture is heated until lithium sulfate is formed. The sulfate
is then leached from the mass, neutralized with limestone, and
filtered. Soda ash is added to the sulfate solution in order to
precipitate lithium carbonate from which most of the other
compound forms are prepared. In the alkali treatment, spodumene
is stage-calcined with powdered limestone and hydrolyzed with
steam to produce a water-soluble lithium oxide. This can be
easily recovered and converted to the desired lithium compound.
Certain natural brines are also a source of lithium. At Searles
Lake, California, brine (0.033 percent lithium chloride) is first
concentrated in evaporators causing several salts to precipitate,
including dilithium sodium phosphate, sodium chloride, and a
mixture of other sodium salts. Through a combined
leach-flotation process the lithium compound is recovered as
crystals and then fed to a chemical facility to be converted to
lithium carbonate. The brines at Silver Peak, Nevada (0.244
percent LiCl) are concentrated to a LiCl content of 6 percent by
solar evaporation. This concentrate is then pumped to a nearby
mill where a soda ash process changes the chloride to solid
lithium carbonate. Lithium metal is produced by the electrolysis
of lithium chloride. Figure 11 shows the domestic lithium
deposits.
59
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CLAYS
Clays and other ceramic and refractory materials differ primarily
because of varyinq crystal structure, presence of significant
non-clay materials, variable ratios 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 problem 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 AlJ2O3Si Si8O22(OH) 4• (\H2O.
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 pined 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
60
-------
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, fullerfs 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 (i.e. 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. The supply-demand
relationships for clays in 1968 are shown in Figure 15.
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
by weathering, drying, grinding, sizing, and granulation.
The principal uses of bentonites are for 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 montmorillonite 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 exchange of
iron and magnesium. The placement of the relatively large
61
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WORLD PRODUCTION
•/ 350,000
1
Oiher
Nortl* Amertco
*/ 12.767
South Amtrlco
-V 12.000
USSR.
1/55,000
Wo$t Germany
-S/25,000
Jopon
«/ 28,000
France
«/!6,000
Other Asia
«/ 37,000
Africa
.1/10,000
Holy
J/ 17.000
Gttor Coy^'rlei
i/ 61, 000
1
Unit ft d States
5T.233
United King(fcff
S/ 16,000
Unitt:
KEY
Thousand «^o
'
— i
n
^ i
— i
rt lo
Kaolin
4.201
Ball clay
630
Firs cl«»
8,054
Btntonlt*
2.436
Fullari eortli
922
Olh«r elay«
40,939
Import], kaolin
75
Imports, ball
IS
ImpcrH.oilttr
4
r>*
l^i^BI
•—^m
, U.S.t«»pl» . U.S.dtmand
37,529 ^^ 59,810
Exports
1,320
i/ Esllmau
SIC Standard Industrial Classification
„
ractorlii
i
u
!
Structure! clay product
23,636
Hydraulic ctmint
11,264
Cipandedthaltand
clay
(SIC3II3I
9.280
Iron ond ttcel
isienin
2,400
.Jonferrout mtloll
ISICJli. 33411
1.125
Clots
IS 1C Jtll-Jtlll
477
Paper mtllt
ISIC3IIII
1.800
ISIC313SI
650
Psiteryond related
products
tsicstt) '
494
Drilling mud
If 1C I >S)I
520
Iron ore
410
Older
3.714
Figure 1 5
Supply-Demand Relationships for Clays, 1968.
-------
sodium and calcium ions between the silica and alumina sheets in
the basic montmorillonite lattice structure are responsible for
the important property of swelling in water. Sodium bentonite is
principally mined 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 refrac-
toriness or on the intended usage for refractories; hence they
are also called refratory clays, and stoneware clay for such
items as crocks, jugs, and jars. Their most notable property is
their high fusion point. 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 burley 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 properties of the clays and of products made from
them. In general the higher the alumina content is, 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. Fire clays are processed by crushing, calcining
and final blending.
FULLER'S EARTH (SIC IH5H)
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
requirements 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,
beverages, 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 troad 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 kaolinic clays. 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
63
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quantities of montmorillonite and organic material. They are
usually much finer grained than kaolins due to their sedimentary
origin and 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 properties, which are much the same as those for kaolin.
The prinicpal use for ball clay is in whitewares (i.e. china).
MISCELLANEOUS CLAYS
Miscellaneous clays 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
characteristics of the products. 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.
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 are orthoclase or
microcline (both K2O«Aj.2O3»6Siq2) , albite (Na20«Al2O.3«6SiO.2) , and
anorthite (CaO»Al_2O_3«2SiOji!) . 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, 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 prominent that feldspathic sands
are considered under industrial sands.
Nepheline syenite is a feldspathic, igneous reck which contains
little or no free silica, but does contain nepheline
(KjJO«3Na_2O»4Al2q3»9Si(D2). The valuable properties of nepheline
are the same 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
this is the only mining of this material in the U.S. 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 the overburden ratio will permit and land use
conflicts are not 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
65
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sequence continues with acid circuit flotation in three stages,
each staqe preceded fcy desliming and conditioning. In the first
flotation step an amine collector floats off mica, and the second
uses sulfonated oils to separate iron bearing minerals. The
third step floats the feldspar with another amine collector,
leaving behind a residue that consists chiefly of quartz.
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
A1203_.SiO_2. Dumortierite contains boron, and topaz contains
fluorine, both of which vaporize during the conversion to mullite
(3Al203.2Si02) .
With the exception of the production of a small amount of
by-product kyanite and 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. 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 and kyanite
concentrates started in 1968. The principal end uses for kyanite
are iron and steel, primary nonferrous metals, secondary non-
ferrous metals, boilers and glass.
MAGNESITE (SIC 1459)
Magnesium is the eighth most plentiful element in the earth and,
in its many forms, comprises 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 magnesium 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. It is the third most abundant element dissolved in
sea water, averaging 0.13 percent magnesium by weight.
66
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Extraction of magnesium from sea water is so closely associated
with the manufacture of refractories that it is discussed in the
clay and gypsum products point source category.
Dolomite is the double carbonate of magnesium and calcium, and is
a sedimentary rock commonly interbedded with limestone, extending
over large areas of the United States. Most dolomites probably
result from the 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 occur 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 mag-
nesite 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 13
centimeter (5 inch) size. It is further crushed to minus 6.U
centimeters (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).
67
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When the source of magnesia is sea water or
waters are treated with calcined dolomite or
oyster shell by calcining, to precipitate
magnesium hydroxide. The magnesium hydroxide
to remove water, after which it is conveyed to
to temperatures that may be as high as 1850°C
calcined product contains approximately 97
principal uses for magnesium compounds follow:
well brine, the
lime obtained from
the magnesium as
slurry is filtered
rotary kilns fired
(3,360°F). The
percent MgO. The
Compound and grade
Magnesium oxide:
Refractory grades
Caustic-calcined
Use
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 (SIC 1459)
68
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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. The
mining of shales depends on the nature of the specific deposit
and on the amount and nature of the overburden. While some
deposits are mined underground, the majority of shale deposits
are worked as open guarries.
Shales and common clays are used interchangeably in the
manufacture ' of formed and fired ceramic products and are
freguently mixed prior to processing for optimization of product
properties. Ceramic products consume about 70 percent of the
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 with a density of 960-1800 kg/m3 (60-110 lb/ft.3).
Probably 20 to 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 primarily achieves particle size reduction
and removal of all but a very small fraction of iron bearing
minerals. Aplite 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 or blasting.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE (SIC 1496)
The mineral talc is a soft, hydrous magnesium silicate,
3MgO«4SiO.2«H2;O. The talc of highest purity is derived from
sedimentary magnesiuir carbonate rocks; less pure talc from ultra
basic igneous rocks.
Steatite has been used to designate a grade of industrial talc
that is especially pure and is suitable for making electronic
insulators. Block steatite 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
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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
Al2q3*4Si02«H20. It is principally found in North Carlina.
Wonderstone is a term applied to a massive block pyrophyllite
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, Cali-
fornia, 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 the pyrophyllite
statistics.
The facility size breakdown is as follows:
Numbers of Production
Facilities tons/yr
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 methods. Underground operations are usually entirely
within the ore body and thus reguire timber supports that must be
carefully placed because of the slippery nature of the ore.
Mechanization of underground mines has become common in recent
years, especially in North Carolina and California where the ore
body ranges in thickness from 3 to 4.6 meters (10 to 15 ft) and
dips 12 to 19 degrees from horizontal. In those mines where the
ore body suffers vein dips of greater than 20 degrees, complex
switchbacks 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.H by 3.0 meters (U by 8 by 10 ft) which
are cut into slices by gang saws with blades spaced about 7.6 cm
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(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 is done 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 guartzite pebbles as a grinding medium. These mills
are ordinarily in closed circuit with air separators but
sometimes are used as batch grinders, especially if reduction to
finer particle sizes is required.
Talc and pyrophyllite are amenable to processing in an additional
microgrinding apparatus. Microgrinding or micronizing is also
done in fluid systems with subsequent air drying of the product.
The principal end uses for talc and its related minerals are
ceramics, paint, roofing, insecticides, paper, refractories,
rubber and toilet preparations.
NATURAL ABRASIVES (SIC 1«»99)
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. Of
interest here are the natural abrasive minerals cleamorid,
corundum, emery, pumice, tripoli and garnet. Of lesser
importance are feldspar, calcined clays, chalk and silica in its
many forms such as sandstones, sand, flint and diatomite.
Abrasive sand is covered in industrial sand.
CORUNDUM
Corundum is a mineral with the composition A.12O3 that was
crystallized in a hexagonal form 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 imported corundum per year (1968 data), and further
consideration will be dropped.
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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 downturn in demand for
emery resulting from the increasing competition with such arti-
ficial abrasives as A1J2CX3 and Sic. Production is estimated to be
11,000 kkg/yr (10.000 tons/yr). Emery is not considered further
in this report because it is not economically significant and no
environmental problems are 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 occur in the Seneca,
Missouri area and in southern Illinois. The Missouri ore
resembles tripolite and was incorrectly named tripoli. This name
has persisted for the ore from the Missouri-Oklahoma field. The
material from the southern Illinois area is often refered to as
"amorphous" or "soft" silica. In both cases the ore contains 97
to 99 percent Si02 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 shallow overburden of approximately 2 meters
(six ft) in thickness coupled with tripoli beds ranging from 0.6
to 4.3m (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 (C.25 to 0.50 in); the silica
is fine ground in tube mills using flint linings and flint
pebbles in a closed circuit system with bowl classifiers. The
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resulting sized product is thickened, dried and packed for
shipment.
Tripoli is primarily used as an abrasive or as a constituent of
abrasive materials polishing and buffing 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, and pipe
coatings. Total U. S. production of tripoli in 1971 was of the
order of 68,000 kkg, some 70 percent of which was used as an
abrasive, the remainder as filler.
GARNET
Garnet is an orthosilicate having the general formula
3RO«XJ2OJ«3Si02 where the bivalent element R may be calcium,
magnesium, ferrous iron or manganese; the trivalent element X,
aluminum, ferric ircn or chromium, rarely titanium; further, the
silicon is occasionally replaced by titanium.
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 metamorphic
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 slivery
grain shape, a feature of particular importance in the coated
abrasive field.
The New York mine is worked by open guarry methods. The ore is
guarried 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
foot 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.
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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 and the remainder for sand blasting
and miscellaneous uses.
DIATOMITE (SIC 1499)
Diatomite is a 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 microscopic plants. 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. Commercially useful deposits
of diatomite show SiO2 concentrations ranging from a low of 86
percent (Nevada) to a high of 90.75 percent (Lompoc, California)
for the United States producers; the Si
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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 million
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 the
later tertiary of the Pleistocene age (less than 12 million years
old) .
Currently, the only significant production of diatomite within
the U.S. is in the western states, with California the leading
producer, followed fcy 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 reguires 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 usually without the necessity of previous
fragmentation by drilling or blasting.
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. oaghouse 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 80 to 260 kg/m3 (5 to 16
lbs/ft3) for ground diatomite. The processed material has
dimensional stability to temperatures of the order of 400° C.
The principal end uses for diatomite are thermal insulation,
industrial and municipal water treatment, and food, beverage and
pharmaceutical processing.
GRAPHITE (SIC 1499)
Natural graphite is the mineral form of elemental carbon, crys-
tallized predominately in the hexagonal system and found in
silicate minerals of varying kind and percentage. The three
principal types of natural occurrence of graphite are classified
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as lump, amorphous and crystalline flake, 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 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 meta-
morphism of coalbeds by nearby intrusions. Although the purity
of amorphous graphite depends on the purity of the coalbeds from
which it was derived, it is usually associated with sandstones,
shales, slates and limestones and contains accessory minerals
such as guartz, clays and iron sulfides.
Flake graphite, which is believed to have been formed by meta-
morphism 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 a 5,5 m (18 ft)
bench pan. The ore is hard and tough and thus reguires 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
guartz and other sharp gangue materials, thus rapidly reducing
the flake size. However, if the flake can be removed from most
of the guartz and other sharp minerals soon enough, subseguent
grinding will usually reduce the size of the remaining gangue
with little further reduction in the size of the flake. Impact
grinding or ball milling 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 guartz, mica, and other gangue
minerals inadvertently become smeared with fine graphite, making
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them floatable and 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 layer of mica between outer layers of graphite
making it next to impossible to obtain a high grade product by
flotation.
MISCELLANEOUS NON-METALLIC MINERALS
(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 (NaAlSi2:oj>) contains varying amounts of iron, calcium
and magnesium is found only in Asia. Nephrite is a tough compact
variety of the mineral tremolite (Ca2Mg5Si8O.22(OH) 2) which is an
end member of an isomorphous series wherein iron may replace
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 guarried, 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 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 guite 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 2,940 kkg (3,240 tons) with a value of
$670,000. This production is neither economically nor
environmentally significant and will not be treated further in
this report.
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SECTION IV
INDUSTRY CATEGORIZATION
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 10 lists the subcagegories in this
report.
Manufacturing Processes
Each commodity can be further sutcategorized into three very
general classes - dry crushing and grinding, wet crushing and
grinding (shaping), and crushing and beneficiation (including
flotation, heavy media, et al). Each of these processes is
described in detail in Section V of this report. The type of
manufacturing process can significantly affect the amount and
type of pollutants generated and their treatability. It can
therefore be a basis for further subcategorization. Water from
the mine, such as mine pumpout and runoff, is considered
separately from process water unless the two are technically or
economically inseparable.
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, differencies in ore grades do
not generally affect the ability to achieve the effluent
limitations. In cases where it does, different processes are
used, and subcategorization is better applied by process type as
described in the above 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. 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 previously, pure
products usually result from different beneficiation processes,
and subcategorization is better applied there.
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TABLE 10
Industry Categorization
Commodity
Dimension Stone
Crushed stone
Construction
Sand and Gravel
Industrial Sand
Gypscji
Asphaltle Minerals
Asbestos and
Wollastonlte
Lightweight
Aggregates
Mica sad Sericite
SIC Codu
1422. 1423,
1429, 1499
1442
1446
1492
1499
1499
1499
1499
Barite
Fluorspar
Salines from
Brine Lakes
Borax
Potash
Trona
Sodlua Sulfate
Bock Salt
Phosphate Rock
Sulfur (Frasch)
Mineral Figments
Lithium Minerals
Bentonite
Fire Clay
Fuller's Earth
Kaolin
Ball Clay
Feldspar
Kyanlte
Magnetite
Shale & Common
Clay, NEC
Talc Minerals Croup
Natural Abrasives
Dlatomlte
Graphite
Misc. Minerals.
Not Elsewhere
Classified
1472. 3295
1473, 3295
various
1474
1474
1474
1474
1476
1475
1477
1479
1479
1452
1453
1454
1455
1455
1459
1459
1459
1459
1496
1499
1499
1499
1499
Subcategory
No further aubcategorizatlon
Dry
Wet
Flotation
Dry
Wet
Dredging, on-land processing
Dredge water plant intake vater
Dry
Wet
Flotation (acid and alkali)
Flotation (HF)
Dry
Dry, wet scrubbers
EMS
Bituminous limestone
Oil impregnated diatonlte
Silaonlte
Asbestos, Dry
Asbestos, Wet
Kollastonite
Ferllte
Pumice
Vermiculice
Dry
Wet
Wet beneficlatlon
either no clay CT
general purpose
clay by-product
Wet beneficlation
cer. gr. by-product
Dry
Wet
Flotation
Heavy media separation
notation
Drying and pelletl^lng
No further subcategorization
No further subcategorization
No further subcategorization
No further subcategorizatioa
No further subcategorization
No further subcategorization
Flotation units
Non-flotation units
Anhydrite
On-shore
Off-shore
No further subcategorization
No further subcategorization
No further subcategorization
No further subcategorization
Attapulglte
Montnorillonlte
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 subcacegorization
No further aubcategorlzation
Shale and common clay
Apllte
Talc minerals group, dry process
Talc minerals Group, ore mining
& washing
Talc minerals group, ore mining,
heavy media and flotation
Garnet
Tripoli
No further subcategorization
No further subcategorization
Jad*
Novocul Ite
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Facility Size
For this segment of the industry, information was obtained from
more than 600 different mineral mining sites. Capacity varied
from as little as 1 to 12,500 kkq/day. Setting standards based
on kg pollutant ioer kkg of production minimizes the differences
in facility sizes. The economic impact on facility size is
addressed in the economic analysis study.
Facility Age
The newest facility studied was less than a year old and the
oldest was 150 years old. There is no correlation between
facility age and the ability to treat process waste water to
acceptable levels of pollutants. Also the eguipment in the
oldest facilities either operates on the same principle or is
identical to eguipment used in modern facilities. Therefore,
facility age was not an acceptable criterion for categorization.
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SECTION V
WATER USE ANE WASTE CHARACTERIZATION
Waste water originates in the mineral mining and processing
industry from the following sources.
(1) Non-contact cooling water
(2) Process generated water - wash water
transport water
scrubber water
process and product consumed water
miscellaneous water
(3) Auxiliary process water
(H) Storm and ground water - mine dewatering
mine runoff
plant runoff
Non-contact cooling water is defined as 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. The largest use of non-contact
cooling water is for the cooling of crusher bearings, dryers,
pumps and air compressors.
Process generated waste water is defined as that water which, in
the mineral processing operations such as crushing, washing, and
benefication, comes into direct contact with any raw material,
intermediate product, by-product or product used in or resulting
from the process. Examples of process generated waste water
follow. Insignificant guantities of contact cooling water are
used in this segment of the mineral mining industry. When used,
it usually either evaporates or remains with the product. Wash
water is used to remove fines and for washing of crushed stone,
sand and gravel. Water is widely used in the mineral mining
industry to transport ore between various process steps. Water
is used to move crude ore from mine to mill, from crushers to
grinding mills and to transport tailings to final retention
ponds. Particularly in dry processing wet scrubbers are used for
air pollution control. These scrubbers are primarily used on
dryers, grinding mills, screens, conveyors and packaging
equipment. Product consumed water is often evaporated or shipped
with the product as a slurry or wet filter cake. Miscellaneous
water uses vary widely among the facilities with general usage
for floor washing and cleanup. The general practice is to
discharge such streams without treatment or combine them 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
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stockpiles. This water is usually low volume and is either
evaporated or adsorbed on the ore.
Auxiliary process water is defined as that used for processes
necessary for the manufacture of a product but not contacting the
process materials, for example influent water treatment.
Auxiliary process water includes blowdowns from cooling towers,
boilers and water treatment. The volume of water used for these
purposes in this industry is minimal.
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 be
contaminated. Storm water and runoff can also become
contaminated at the processing site from storage piles, process
eguipment and dusts that are emitted during processing. Plant
runoff that does not co-mingle with process waste water is not
process waste water. This includes storage pile runoff.
The quantity of water usage ranges from 0 to 726,400,000 I/day
(191,900,000 gal/day). In general, the facilities using very
large quantities of water use it for heavy media separation,
flotation, wet scrubbing and non-contact cooling.
DIMENSION STONE (SIC 1411)
The quarrying of dimension stone can be accomplished using one of
six primary techniques. some can be used singly; most are used
in various combinations. These techniques, their principal
combinations, and their areas of use, are discussed as follows:
(1) Drilling, with or without broaching, is done dry or wet. On
occasion, shallow drilling of holes a few centimeters apart is
the prelude to insertion of explosive charges, or to insertion of
wedges, or wedges with two especially shaped iron strips
("plugs-and-feathers"). On other occasions, drilling deeper
holes, followed by removal of stone between holes (broaching) is
the primary means of stone cutting. Drilling is either dry or
wet with water serving to suppress dust, to wash away stone chips
from the working zone, and to keep the drills cool and prolong
the cutting edge. Drilling to some extent is necessary in
virtually all dimension stone quarrying.
(2) Channel machines are simple, long, semi-automated,
multiple-head chisels. They are electrically or steam
powered (with the steam generating unit an integral part of
each machine), and are primarily used on limestone along with
other technigues. The machines are always used with water,
primarily to remove stone chips which are formed by machine
action.
-------
(3) Wire saving is another technique requiring the use of water.
Generally, a slurry of hard sand or silicon carbide in water
is used in connection with the saw. The use of wire saws is
probably not justified in small quarries, as the initial
setup is time consuming and costly. However, the use of wire
saws permits decreased effort later at the saw facility, and
will result in decreased loss of stone. Wire saws are used
chiefly on granite and limestone.
(4) Low level explosives, particularly black powder, are used in
the quarrying of slate, marble, and mica schist.
(5) Jet piercing is used primarily with granite in the dimension
stone industry. This technique is based on the use of high
velocity jet flames to cut channels. It involves the
combustion of fuel oil fed under pressure through a nozzle to
attain jet flames of over 2600°C (5000°F). A stream of water
joins the flame and the combined effect is spalling and
disintegration of the rock into fragments which are blown out
of the immediate zone.
(6) Splitting techniques of one sort or another seem to be used
in the quarry on nearly all dimension stones. Splitting
always requires the initial spaced drilling of holes in the
stone, usually along a straight line, and following the
"rift" of the stone if it is well defined. Simple wedges, or
"plugs-and-feathers" are inserted in the holes and a workman
then forces splitting by driving in the wedges with a sledge
hammer. This technique appears crude, but with a skilled
workman good cuts can be made.
After a large block of stone is freed, it is either hoisted on to
a truck which drives from the floor of the quarry to the
facility, or the block is removed from the quarry by means of a
derrick, and then loaded on a truck.
Most dimension stone processing facilities are located at or
close to the quarry. On occasion, centrally located facilities
serve two or more quarries (facilities 3029, 3038, 3053, 3007,
3051). To a much lesser extent, one quarry can serve two or more
processors (facilities 330U and 3305). Also in a well defined,
specialized producing area such as Barre, Vermont, two large
quarriers, who are also stone processors, sell blocks and/or
slabs to approximately 50 processors. However, the most common
situation is that in which the processor has his own quarry. In
this study, no situation was seen in which a quarry was operated
without an accompanying processing facility.
In dimension stone processing, the first step is to saw the
blocks into slabs. The initial sawing is accomplished using gang
saws (large hack saws), wire saws, or occasionally, rotating
diamond saws. All saw systems use considerable water for cooling
85
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and particle removal, but this water is usually recycled.
Generally, the saw facility is operated at the same physical
location as the finishing facility, and without any conscious
demarkation or separation, but in a few cases the saw facility is
either at a separate location (facilities 303U and 3051), is not
associated with any finishing operations (facilities 3008, 3010
and 5600), or is separately housed and operated but at the same
location (facilities 3007 and 3001).
After the initial sawing of blocks to slabs of predetermined
thickeness, finishing operations are initiated. The finishing
operations used on the stone are varied and are a function of the
properties of the stone itself, or are equally affected by
characteristics of the end product. For example, after sawing,
slate is hand split without further processing if used for
structural stone, but is hand split, trimmed, and punched if
processed into shingles, and it is hand split and trimmed if
processed into flagstone. Slate is rarely polished, as the rough
effect of hand splitting is desirable. Mica schist and sandstone
are generally only sawed, since they are used primarily for
external structural stone. Limestone cannot be polished, but it
can be shaped, sculptured and machined for a variety of
functional and/or primarily decorative purposes. Granite and
marble are also multi-purposed stones and can take a high polish.
Thus polishing eguipment and supplies, and water usage, are
important considerations for these two large categories of stone.
Dolomitic limestone can be polished, but not to the same degree
as granite or marble. Generally most of this stone is used
primarily for internal or external structural pieces, veneer,
sill stone, and rubble stone. A schematic flow sheet for
dimension stone quarrying and processing is given in Figure 16.
Extremely large quantities of stone are quarried in the dimension
stone industry, and yields of good quality stone are quite low
and variable, from 15 percent to 65 percent and with 0.5 to 5.7
kkg of waste stone per kkg of product. The lowest yields are
characteristic of the stones which are generally highly polished
and therefore require the most perfection (granite and marble).
Low yields (18 percent) also occur in slate due to large
quantities of extraneous rock. Most of the losses occur at the
quarry but some unavoidable losses also occur in the saw
facilities and finishing facilities.
Some quarries require no water: mica schist, dolomitic limestone,
slate and sandstone, (facilities 5600, 3017, 3018, 3053, 3039,
3040), as do some marble, travertine marble, and granite
(facilities 3051, 3034, 3001, 3029). Ground or rain waters do
accumulate in these quarries. Most limestone and some granite
quarries do use water for sawing or channel cutting, (facilities
3038, 330U, 3305, 3306, 3007, 3008, 3009, 3010) therefore, ground
and rain water is retained, and other sources of water may also
be tapped for makeup. This water is continuously recycled into
86
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__WATER_
\ OPTIONAL)"
QUARRY
*S*
1 _____ J
oo
MAKE-UP
WATER
RECYCLE
SAW PLANT
W
POND OR
ABANDONED
QUARRY
MAKE-UP
WATER
RECYCLE
FINISHING
PLANT
• PRODUCT
SETTLING
PONDS
DIMENSION
FIGURE 16
STONE MINING
AND PROCESSING
-------
the quarry sump and is rarely discharged. Water is also used in
wet drilling, but this quantity is small.
All saw facilities use water and the general practice is to
recycle after settling most of the suspended solids. The raw
waste load of TSS from saw facilities can be significant. The
same is true of untreated effluents from finishing facilities.
In many cases, the saw facilities and the finishing facilities
are under the same roof, in which case the water effluents are
combined.
In Table 11, water use data are presented for dimension stone
facilities having reliable data available. Combined saw facility
and finishing facility raw water effluents vary from 4,340 to
43,400 1/Wcg of product (1,040 to 10,400 gal/ton). Water usage
varies due to varying stone processes, water availability, and
facility attitudes t>n water usage.
The quality of intake water used in dimension stone processing
appears to be immaterial. For the most part, river, creek, well,
abandoned quarry, or lake water is used without pretreatment.
Occasionally pretreatment in the form of prior elementary
screening or filtration is performed (facilities 3018, 3051), and
in only two instances is city water used (facility 3007, 3029) as
part of the makeup water.
88
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TABLE 11
Dimension Stone Water Use
Stone and
Plant
Mica Schist
5600
Slate
3053
Dolomitic
Limestone
3039
3040
Limestone
3007
3009
3010*
Granite
3001
3029
3038
Marble
3051
3304
3305
3306
Makeup Water
1/kkg of
stone processed
(gal/ton)
20 (5)
450 (110)
1,250 (300)
13,000 (3100)
540 (130)
unknown
unknown
unknown
840 (200)
1,600 (390)
100,000 (24,000)
590 (140)
unknown
1,300 (300)
Water Use,
processed
Saw Plant
4,460
unknown
unknown
unknown
16,600
unknown
9,800
7,350
unknown
unknown
100,000
unknown
unknown
unknown
1/kkg of stone
(gal/1000 Ib)
Finish Plant
none
unknown
unknown
unknown
1,600
unknown
7,360
unknown
unknown
unknown
unknown
unknown
unknown
Combined
4,460
4,550
unknown
13,000
18,200
6,030
9,800
14,700
3,900
43,400
unknown
5,940
39,800**
6,500
* No finishing plant
** Primarily a saw plant which ships slabs to 3304 for finishing.
89
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CRUSHED STONE (SIC 1U22, 1423, 1429)
Three basic methods of extraction are practiced: (1) removal of
raw material from an open face quarry; (2) removal of raw material
from an underground mine (approximately 5 percent of total
crushed stone production) ; and (3) shell dredging, mainly from
coastal waterways (approximately 1 percent of total crushed stone
production) . Once the raw material is extracted, the methods of
processing are similar, consisting of crushing, screening,
washing, sizing, and stockpiling. For approximately 0.2 percent
of total crushed stone production, flotation techniques are
employed to obtain a calcite (CaCO_3) product. The industry was
divided into the following subcategories:
(1) Dry process
(2) Wet process
(3) Flotation process
Shell dredging
These facilities contacted are located in 38 states in all areas
of the nation representing various levels of yearly production
and facility age. Production figures range from 36,000
1,180,000 kkg/yr (40,000-1,300,000 tons/yr) and facility ages
vary from less than one year to over 150 years old. Figure 17
shows the different methods of processing.
DRY PROCESS
Most crushed stone is mined from guarries. After removal of the
overburden, drilling and blasting techniques are employed to
loosen the raw material. The resulting quarry is characterized
by steep, almost vertical walls, and may be several hundred
meters deep. Excavation is normally done on a number of
horizontal levels, termed benches, located at various depths. in
most cases, front-end loaders and/or power shovels are utilized
to load the raw material into trucks which in turn transport it
to the processing facility. In some cases, however, the raw
material is moved to the facility by a conveyor belt system
perhaps preceded by a primary crusher. Another variation is the
use of portable processing facilities which can be situated near
the blasting site, on one of the quarry benches or on the floor
of the quarry. In this situation, the finished product is
trucked from the quarry to the stockpile area. Specific methods
vary with the nature and location of the deposit.
No distinction is made between permanent facilities and portable
facilities since the individual operations therein are basically
identical. At the processing facility, the raw material passes
through screening and crushing operations prior to the final
sizing and stockpiling. Customer demands for various product
grades determine the number and position of the screens and
crushers. No process water is used in the crushing and screening
90
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FIGURE 17
PSOOUCT
PIT PUMPOUT
CRUSHED STONE MINING AND PROCESSING
(DRY)
PIT
PUMPOUT
OOOCT
EFFLUENT RECYCLE
CRUSHED STONE MIN'IWS AND PROCESSING
(WET)
CONDITIONERS
FROTHERS 1
WATER | WATER j WATER VENT
QUARRY
j Ml 1 t
— — fj CRiJSHif.'O
JsCRrCNING
OR
' I V/CT
I ''
-_
FLOTATION
j- 1 WET
MILLING
(. | j 1
PITP,,..=>
-------
of dry process crushed stone. Many operators dewater their
quarries because of ground water, rain, or surface runoff.
Approximately half of the quarries studied dewater their quarries
either on an intermittent or continual basis. Incidental water
uses include non-contact cooling water for cooling crusher
bearings and water used for dust suppression, which is adsorbed
onto the product and does not result in a discharge.
CRUSHED STONE, WET PROCESS
Excavation and transportation of crushed stone for wet processing
are identical to those for dry processing. Wet processing is the
same as dry processing with the exception that water is added to
the system for washing the stone. This is normally done by
adding spray bars to the final screening operation after
crushing. In many cases, not all of the product is washed, and a
separate washing facility or tower is incorporated which receives
only the material to be washed. This separate system will
normally only include a set of screens for sizing which are
equipped with spray bars. In the portable processing facility, a
portable wash facility can also be incorporated to satisfy the
demands for a washed material. At facility 5662, the finished
product from the dry facility is fed into a separate unit
consisting of a logwasher and screens equipped with spray bars.
Incidental water is used for non-contact cooling and/or dust
suppression. Use varies widely as the following shows:
Facility
1001
1002
1003
1004
1021
1022
1023
1039
1040
1212
1213
1215
1221
1974
5640
Hater Use
1/kkg of product fgal/1000 Ib)
Non-contact Cooling Dust Suppression
None
None
None
None
None
8
Unknown
None
None
None
None
290
None
17
None
None
None
None
None
500
None
16
Unknown
13
None
None
8
None
60
None
Water necessary for the washing operations is drawn from any one
or combination of the following sources: quarries, wells,
rivers, company owned ponds, and settling ponds. There is no set
quantity of water necessary for washing crushed stone as the
amount required is dependent upon the deposit from which the raw
92
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material is extracted. A deposit associated with a higher
percentage of fine material will require a larger volume of water
to remove impurities than one with a lower percentage of fines.
A second factor affecting the amount of washwater is the degree
of crushing involved. The amount of undesirable fines increases
with the number of crushing operations, and consequently a
greater the volume of water is necessary to wash the finer grades
of material.
Washwater
Percent of 1/kkg of
Facility washed material product (gal/tony
5663 8 40 (10)
5640 15 670 (160)
1439 40 1050 (250)
1219 50 1250 (300)
1004 100 330 (80)
1003 100 690 (165)
Less than 10 percent of all crushed limestone operators dry their
product. Approximately 5 percent of these operators employ a wet
scrubber in conjunction with the dryer as a means of air
pollution control. Facility 1217 uses a rotary dryer for
approximately 30-40 percent of the total production time. The
wet scrubber associated with this dryer utilizes water at the
rate of 2,600 1/kkg of dried product (690 gal/ton).
The quantity of raw waste varies as shown by the tabulation as
follows:
Facility Paw Waste Facility Raw waste
Load, kg/kkg Load, kg/kkg
of Product of Product
1001 40 1212 270
1002 50 1213 30
1003 40 1215 10
1004 150 1221 130
1021 80 1974 22
1023 20 5640 10
1039 20 5664 180
CRUSHED STONE, FLOTATION PROCESS
Marble or other carbonaceous rock is transported from the quarry
to the processing facility where it is crushed, screened or wet
milled and fed to flotation cells. Impurities are removed in the
overflow and the product is collected from the underflow. It is
further wet milled to achieve a more uniform particle size,
dried, and shipped.
93
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The water use for the three facilities is outlined as follows.
There are considerable variations in process and mine pumpout
waters,
1/kkg of product (gal/ton)
Type 1975 3069 1021
process 151,000 1,900 2,570
(36,000) (1,170) (610)
cooling 22,700 850 -----
(5,400) (200)
dust control 1,510 1,400
(360) (335)
boiler 6,600
(1,580)
mine unknown none 16,000
pumpout (3,800)
Facility 1975 also employs some of this process water to wash
other materials.
Process raw wastes consist of clays and fines separated during
the initial washing operations and iron minerals, silicates,
mica, and graphite separated by flotation.
kg/kkg jof product (lfc/1000 Ib)
waste 1975 3069
clays and 1,000 unknown
fines
flotation 50-100 50-100
wastes
(solids)
In addition to the above, the flotation reagents added (organic
amines, fatty acids and pine oils) are also wasted. The
quantities of these materials are estimated to range from 0.1 to
1.0 kg/kkg of material.
SHELL DREDGING
Shell dredging is the hydraulic mining of semi-fossil oyster and
clam shells which are buried in alluvial estuarine sediments.
Extraction is carried out using floating, hydraulic suction
dredges which operate in open bays and sounds, usually several
miles from shore. This activity is conducted along the coastal
Gulf of Mexico and to a lesser extent along the Atlantic coast.
-------
Shell dredges are self-contained and support an average crew of
12 men working 12 hours/day in two shifts.
All processing is done on board the dredge and consists of
washing and screening the shells before loading them on
tow-barges for transport to shore. Shell is a major source of
calcium carbonate along the Gulf Coast states and is used for
construction aggregate and Portland cement manufacturing. Shell
dredging and on-board processing is regulated under section
of the Act, Permits for Dredged or Fill Material.
95
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CONSTRUCTION SAND AND GRAVEL (SIC 14U2)
Three basic methods of sand and gravel extraction are practiced:
(1)dry pit mining above the water table; (2)wet pit mining by a
dragline or barge-mounted dredging equipment both above and below
the water table; and (3)dredging from public waterways, including
lakes, rivers, and estuaries. Once the raw material is
extracted, the methods of processing are similar for all cases,
typically consisting of sand and gravel separation, screening,
crushing, sizing, and stockpiling. The industry was divided into
dry process, wet process and dredging with on-land processing.
The facilities contacted are located in 22 states in all regions
of the nation representing production levels from 10,800 kkg/yr
(12,000 tons/yr) to over 1,800,000 kkg/yr (2,000,000 tons/yr).
Facility ages varied from less than a year old to more than 50
years old. Figure 18 shows the different methods of processing.
DRY PROCESS
After removal of the overburden, the raw material is extracted
via front-end loader, power shovel or scraper and conveyed to the
processing unit by conveyor belts or trucks. At the processing
facility, the sand is separated from the gravel via inclined
vibrating screens. The larger sizes are used as product or
crushed and re-sized. The degree of crushing and sizing is
highly dependent on the needs of the user.
No water is used in the dry processing of sand and gravel. Mine
pumpout may occur during periods of rainfall or, in the cases of
portable or intermittent operations, prior to the initial
start-up. Most pumpout occurs when the water level reaches a
predetermined height in a pit or low-area sump. Incidental water
uses may include non-contact cooling water for crusher bearings
and water for dust suppression. This latter water either remains
with the product or evaporates.
WET PROCESS
Sand and gravel operations reguiring extraction from a wet pit or
guarry typically use a dragline or a hydraulic dredge to excavate
the material. The hydraulic dredge conveys the raw material as a
wet slurry to the processing facility. After removal of the
overburden, the raw material from a dry pit or guarry is
extracted via front-end loader, power shovel or scraper, and
conveyed to the processing facility on conveyor belts or in haul
trucks.
Water in this subcategory is used to wash the clay or other
impurities from the sand and gravel. State, local, and Federal
specifications for construction aggregates reguire the removal of
clay fines and other impurities. The sand and gravel deposits
96
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FIGURE 18
VO
SUARIY
J
IFfiTNn
•nuw
0
"A!?" *"E"
SEFASATE __ 1
__«,
L
,
\VET
CLASSIFICATION
1 . i
PO.NDS AUD/Oa TKiCKEMERS
.own.
nooucr
SAND AND GRAVEL Mlf.'lNG AND PROCESSING
(DRY)
KTTUMG JUO *»
uivr WATER
»«UVCL MWOUCT
» SMO f
SAND AND GRAVEL MINIMG AND P30CESSIN6
(WET)
I"'
ftW»WLrf™T"*"|
IZE
CftUSM
SCREEN
1
1
I
1
1
1
1
TOW
BARGE
WET
PHCCESSIHO
PLANT
1 ___ -. ____ SMOOL ____ |
SAND AND GRAVEL UXUNB AND PROCESSING
(HMS)
SAND Ai4D GRAVEL MINI.VS AfJD
(DREDGING WITH CN-LAND PROCESSING)
-------
surveyed during this study ranged from 5 to 30 percent clay
content. Facility processing includes washing, screening, and
otherwise classifying to size, crushing of oversize, and the
removal of impurities. Impurities which are
suspendable in water (e.g., clays) generally are washed out
satisfactorily. A typical wet processing facility would consist
of the following elements:
(1) A hopper, or equivalent, receives material transported from
the deposit. Generally, this hopper will be covered with a
"grizzly" of parallel bars to screen out rocks too large to be
handled by the facility.
(2) A scalping screen separates oversize material from the
smaller marketable sizes.
(3) The material passing through the scalping screen is fed to a
battery of screens, either vibrating or revolving, the number,
size, and arrangement of which will depend on the number of sizes
to be made. Water from sprays is applied throughout the
screening operation.
From these screens the different sizes of gravel are
discharged into bins or onto conveyors to stockpiles, or in some
cases, to crushers and other screens for further processing. The
sand fraction passes to classifying and dewatering equipment and
from there to bins and stockpiles. Classifiers are troughs in
which sand particles will settle at different points according to
their weight. The largest and heaviest particles will settle
first. The finest will overflow the classifier and be wasted.
Screens are used to separate the sand from the gravel and to size
sand larger than 20 mesh. Finer sizes of sand are produced by
classification equipment.
A small number of facilities must remove deleterious particles
occurring in the deposit prior to washing and screening.
Particles considered undesirable are soft fragments, thin and
friable particles, shale, argillaceous sandstones and limes,
porous and unsound cherts, coated particles, coal, lignite and
other low density impurities. Heavy-media separation
(sink- float) is used for the separation of materials based on
differing specific gravities. The process consists of floating
the lightweight material from a heavy "liquid" which is formed by
suspension of finely ground heavy ferromagnetic materials such as
magnetite and/or ferrosilicon in water. The "floated" impurities
and the "sink" product (sand and gravel) are passed over separate
screens where the magnetite and/or ferrosilicon are removed by
magnetic separation and recycled. The impurities are usually
disposed of in nearby pits while the product is transported to
the facility for routine washing and sizing.
98
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Process water includes water used to separate, wash, and classify
sand and gravel. Incidental water is used for non-contact
cooling and dust suppression. Water used for sand and gravel
separation enters a rotary scrubber or is sprayed via spray bars
onto a vibratory inclined screen to separate the sand and the
clay from the gravel. The sand slurry is further processed via
hydraulic classification where additional water is usually added.
As the source of the raw material constantly changes, so does the
raw waste load and the amount of water required to remove these
wastes. The following tabulates process water use at selected
facilities:
Facility 1/kkg of gal/ton
product
1006 2500 600
1012 9400 2250
1055 3400 820
1391 1430 340
5630 1460 350
5656 750 180
5666 7400 1800
5681 2000 480
Facilities 1012 and 5666 have markedly higher hydraulic loads
than the others because they use hydraulic suction line dredges.
Raw wastes consist of clays, fine mesh sands (usually less than
150 mesh), and other impurities. Oversize material is usually
crushed to size and processed. The amounts of these wastes are
variable, depending on the nature of the raw material (i.e.,
percent of clay content) and degree of processing at the
facility. Facility 1981, using heavy-media separation prior to
wet processing, floats out 150 kg/kkg of the total raw material
fed to the facility. The following lists the rate of raw waste
generation at several other facilities:
Facility kg/kkg of raw material (lb/1000 Ib)
1006 140
1007 480
1055 50
1056 250
1391 80
3091 110
DREDGING WITH ON-LAND PROCESSING
The raw material is extracted from rivers and estuaries using a
floating, movable dredge which excavates the bottom sand and
gravel deposit by cne of the following general methods: a suction
dredge with or without cutter-heads, a clamshell bucket, or a
99
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bucket ladder dredge. After the sand and gravel is brought
on-board, primary sizing and/or crushing is accomplished with
vibrating or rotary screens, and cone or gyratory crushers with
oversize boulders being returned to the water. The general
practice in this subcategory is to load a tow-barge which is tied
alongside the dredge. The barge is transported to a land-based
processing facility where the material is processed similar to
that described for wet processing of sand and gravel. The degree
of sand and gravel processing on-board the dredge is dependent on
the nature of the deposit and customer demands for aggregate.
Dredges 1010, 1052 and 1051 extract the raw material via
clamshell or bucket ladder, remove oversize boulders, size, and
primary crush on-board. Dredges 1046 and 1048 extract via
clamshell, but have no on-board crushing or sizing. The
extracted material for all the above-mentioned dredges is pre-
dominantly gravel. This gravel must undergo numerous crushing
and sizing steps on land to manufacture a sand product which is
absent in the deposit.
Dredges 1011 and 1009 excavate the deposit with cutter-head
suction line dredges since the deposit is dominated by sand and
small gravel. Dredge 1011 pumps all the raw material to an
on-land processing facility. Dredge 1009, due to the lack of
demand for sand at its location, separates the sand and gravel
on-board the dredge with the sand fraction being returned to the
river. The gravel is loaded onto tow barges and transported to a
land facility where it is wet processed. The dredges in this
subcategory vary widely in capital investment and size. Dredge
1046 consists of a floating power shovel powered by a diesel
engine which digs the deposit and loads it onto a tow barge. A
shovel operator and a few deck hands are on-board during the
excavation which is usually only an eight-hour shift. Dredge
1009 is much larger and sophisticated since it requires partial
on-board separation of sand and gravel. This dredge is manned by
a twelve-man crew per shift, with complete crew live-in guarters
and attendant facilities. This dredge operates 24 hours/day.
Water use at the land facilities is similar to wet processing
subcategory facilities. Process water is used to separate, wash,
and classify sand and gravel. Incidental water includes
non-contact cooling and dust suppression. Water used for dust
suppression averages 15 1/kkg (3.8 gal/ton) of gravel processed.
Water use at the dredge depends on the excavation method. Some
clamshell and ladder bucket dredges do not use process water
because there is no on-board washing. Suction line dredges bring
up the raw material as a slurry, remove the aggregate, and return
the water to the river. Water use at land facilities is variable
depending on the raw material and degree of processing as shown
below:
100
-------
Facility 1/kkq gal/ton
of feed
1009 2200 530
1010 1400 340
1046 1000 240
1048 3440 825
1051 1300 320
1052 1500 360
Raw wastes consist of oversize or unusable material which is
discarded at the dredge and undersize waste fines (-150 mesh)
which are handled at the land-based processing facility. The
amount of waste material is variable depending on the deposit and
degree of processing. On the average, 25 percent of the dredged
material is returned to the river. Waste fines at land
facilities average 10 percent. The following tabulates waste
loads at selected operations:
At Dredge At Land Facility
kg/kkg of feed kg/kkg of feed
Dredge (lb/1000 Ib) (Ib/lOOO Ib)
1009 460 100
1010 none 400
1011 none 150
1046 none 110
1048 none 120
1051 250 60
1052 180 120
The clay content of dredged sand and gravel, usually averaging
less than 5 percent, is less than that of land deposits due to
the natural rinsing action of the river. Unsaleable sand fines
resulting from crushing of gravel to produce a manufactured sand
represent the major waste load at the land facilities.
DREDGING WITH ON-BOARD PROCESSING
The raw material is extracted from rivers and estuaries using a
floating, movable dredge which excavates the bottom sand and
gravel deposit by one of the following general methods: a
suction dredge with or without cutter-heads, a clamshell bucket,
or a bucket ladder dredge. After the sand and gravel is brought
on-board, complete material processing similar to that described
in the wet process subcategory, occurs prior to the loading of
101
-------
tow-barqes with the sized sand and gravel. Typical on-board
processing includes: screening, crushing of oversize, washing,
sand classification with hydraulic classifying tanks, gravel
sizing, and product loading. Numerous variations to this process
are demonstrated by the dredges visited. Dredges 1017 and 1247
use a rotary scrubter to separate the sand and gravel which has
been excavated from land pits, hauled to the lagoon where the
dredge floats, and fed into a hopper ahead of the rotary
scrubber. Dredge 1008 excavates with a revolving cutter head
suction line in a deposit dominated by sand. The sand is
separated from the gravel and deposited into the river channel
without processing. Only the gravel is washed, sized, and loaded
for product as there is little demand for sand at this location.
Dredge 1050 employs bucket ladders, rough separates sand from
gravel, sizes the gravel crushing the oversize, and removes
deleterious materials from the gravel by employing heavy media
separation (HMS) . HMS media (magnetite/ferrous silica) is
recovered, and returned to the process. Float waste is
discharged into the river. Dredge 1049, a slack-line bucket
ladder dredge normally works a river channel. However, during
certain periods of the year it moves into a lagoon where water
monitors "knock down" a shoreline sand and gravel deposit into
the lagoon in front of the buckets. All of the dredges pump
river water for washing and sand classification. Periods of
operation are widespread for the dredges visited. Dredge 1008
operates all year, 24 hours per day (two-12 hour shifts). Dredge
1049 operates two 8 hour shifts for 10 months. Dredging for sand
and gravel in navigable waters is regulated under section 404 of
the Act.
102
-------
INDUSTRIAL SAND (SIC U46)
The three basic methods of extraction are:
(1) Mining of sand from open pits;
(2) Mining of sandstone from quarries; and
(3) hydraulic dredging from wet pits.
Once the raw material is extracted, the basic operations involved
in the production of all types of industrial sand are
classification and removal of impurities. The amount of
impurities in the raw material is dependent upon the percentage
of silica in the deposit. The subsequent level of technology
involved in the removal of these impurities depends on the
desired grade of product. Glass sand, for example, requires a
higher degree of purity than does foundry sand. The industry was
divided into the following subcategories:
(1) Dry Process
(2) Wet Process
(3) Flotation Process
Two of the wet process facilities also use flotation on a small
percentage of their finished product, and are included in the
flotation process subcategory. Production, in the facilities
contacted, ranges from 32,600 - 1,360,000 kkg/yr (36,000 -
1,500,000 tons/yr) and facility ages vary from less than one year
to 60 years. Figure 19 shows the different types of processing.
DRY PROCESS
Approximately 10 percent of the industrial sand operations fall
into this subcategory, characterized by the absence of process
water for sand classification and fceneficiation. Typically, dry
processing of industrial sand is limited to scalping or screening
of sand grains which have been extracted from a beach deposit or
crushed from sandstone. Facilities 1106 and 1107 mine a beach
sand which has been classified into grain sizes by natural wind
action. Sand, of a specific grain size, is trucked to the
facility where it is dried and cooled, and coarse grain is
scalped and stored. Processing of beach sand which is excavated
at differing distances from the shoreline, enables the facility
to process a number of grain sizes which can be blended to meet
customer specifications.
Facilities 1109 and 1110 quarry a sandstone, crush, dry, and
screen the sand prior to sale as a foundry sand. Facility 1108
is able to crush, dry, and screen a sandstone of high enough
purity to be used for glassmaking. Most of the facilities use a
dust collection system at the dryer to meet air pollution
requirements. Dust collection systems are both dry (cyclones and
103
-------
FIGURE 19
SANDSTONE
CUM^Y
OUST
COLLCCTISN
(Y,'£T AND DRY)
1
DRY
SCREEN
I
WASTE
FINES
WASTE
FINES
INDUSTRIAL SAND P/!r!iN3 AND PROCESSING
(DRY)
SCREEN
SOLID
DESLIMINO
4NO
DEWATERING
1
1
THICKENER
OR
CLARirltR
.ri
PRODUCT
I I SS5J2™ SETTLING PON-D *
• PRODUCT
INDUSTRIAL SAND MINING AND PROCESSING
(WET)
HF FLOTATION PROCESS-HF-
ALKALINE FLOTATION PROCESS- CAUSTIC -
JFLOTiTlO^ ASENTS,
J F^DThE^S, COKDITICMERS
ALL PROCESSES<
I SUUFUR1C ACID
VEMT
LAGCCNS AND/OR THICKENERS
•PRODUCT
to FELDSPAR
CO-PRODUCT
INDUSTRIAL SAND MINING AND PROCESSING
(FLOTATION FhOCESScS)
104
-------
baqhouses in facilities 1106, 1109 and 1110) or wet (wet
scrubbers in facilities 1107 and 1108).
No water is used to wash and classify sand in this subcategory.
Facilities 1108 and 1107 use a wet dust collection system at the
dryer. Water flows for these two wet scrubbers are shown below:
Wet Scrubber Water Use Facility 1107 Facility 1108
total flow, 1/min 9460 (2500) 115 (30)
(gal/min)
amount recirculated, 9390 (2480) 0
1/min (gal/min)
amount discharged 0 115 (30)
1/min (gal/min)
amount makeup, 1/min 76 (20) 115 (30)
(gal/min)
Although the five facilities surveyed in this subcategory did not
use non-contact cooling water, it may be used in other
facilities.
WET PROCESS
Mining methods vary with the facilities in this subcategory.
Facility 3066 scoops the sand off the beach, while facility 1989
hydraulically mines the raw material from an open pit. Facility
1019 mines sandstone from a quarry. At this facility water is
used as the transport medium and also for processing. Facility
1019 dry crushes the raw material prior to adding water. An
initial screening is usually employed by most facilities
consisting of a system of scalpers, trommels and/or classifiers
where extraneous rocks, wood, clays, and other matter is removed.
Facility 1102 wet mills the sand to produce a finer grade of
material. At all facilities water is filtered off, and the sand
is then dried, cooled, and screened. Facility 3066 magnetically
separates iron from the dried product. The finished product is
then stored to await shipment. Facility 3066 mines a feldspathic
sand. This, however, does not require any different method of
processing.
There is no predetermined quantity of water necessary for washing
industrial sands as the amount required is dependent upon the
impurities in the deposit. Typical amounts of process water
range from 170 to 12,000 1/kkg product.
FLOTATION PROCESS
Within this subcategory, three flotation techniques are used:
105
-------
(1) Acid flotation to effect removal of iron oxide and ilmenite
impurities,
(2) Alkaline flotation to remove aluminate bearing materials, and
(3) Hydrofluoric acid flotation for removal of feldspar.
In acid flotation, sand or quartzite is crushed, and milled into
a fine material which is washed to separate adhering clay-like
materials. The washed sand is slurried with water and conveyed
to the flotation cells. Sulfuric acid, frothers and conditioning
agents are added and the silica is separated from iron-bearing
impurities. The reagents include sulfonated oils, terpenes and
heavy alcohols in amounts of up to 0.5 kg/kkg of product. In the
flotation cells, the silica is depressed and sinks, and the iron-
bearing impurities are "floated" away. The purified silica is
recovered, dried and stockpiled. The overflow containing the
impurities is sent to the wastewater treatment system.
In alkaline flotation, the process is very similar to that
described above with the following difference: before the
slurried, washed sand is fed to the flotation cell, it is
pretreated with acid. In the cell, it is treated with alkaline
solution (aqueous caustic, soda ash or sodium silicate), frothers
and conditioners. The pH is generally maintained at about 8.5
(versus about 2 in acid flotation). Otherwise, the process is
the same as for acid flotation. Materials removed or "floated"
by alkaline flotation are aluminates and zirconates.
In hydrofluoric acid flotation operations, after the raw sand has
been freed of clays by various washing operations, it is
subjected to a preliminary acid flotation of the type described
above. The underflow from this step is then fed to a second
flotation circuit in which hydrofluoric acid and terpene oils are
added along with conditioning agents to float feldspar. The
underflow from this second flotation operation is collected,
dewatered and dried. The overflow, containing feldspar, is
generally sent to the waste water treatment system.
Facility water uses are shown as follows. Most of the water is
recycled. The unrecycled water for the alkaline and HF processes
is used for the flotation steps. For the acid flotation at least
two facilities (1101 and 1980) have achieved total recycle.
Facility 1019 impounds process discharge as wet sludge. Facility
1103 returns process waste water to the same wet pit where the
raw material is extracted, adding make-up water for losses due to
evaporation.
106
-------
Facility
Process
Recycle
Process
Discharge
Scrubber
(recycle)
Total
1101
1/kkg of product
1019 1980 1103 5691
25,400 2,580 23,200 27,300 8,400
none* none 6,830 5,250
none
none
none
50
(10)
none none
5980
24,200
914
none
25,400 2,930 23,250 34,130 13,650 25,700
* As impounded wet sludge
Process raw wastes from all three flotation processes consist of
muds separated in the initial washing operations, iron oxides
separated magnetically and materials separated by flotation. The
amounts of wastes are given as follows.
Amount kg/kkq of raw material (lb/1000 Ib)
Waste
Source
1101 1019
1980
1103 5691
5980
Clays Washing
Flotation Flotation
tailings
Iron Magnetic
oxides separation
Acid & Flotation
flotation
agents*
Fluorides HF Flota-
(as HF) tion tailings
10
50
none
530
20
none
48
60
12
36
140
none
0.055
3
17
none
165
135
34
0.3
none none
none
none
none
0.45
* Generally flotation agents consist of oils and petroleum
sulfonates and in some cases, minor amounts of amines.
107
-------
GYPSUM
Although some underground mining of gypsum is practiced,
guarrying is the dominant method of extraction. The general
procedure for gypsum processing includes crushing, screening, and
processing. An air-swept roller mill is most commonly used. Two
facilities use heavy media separation for beneficiation of a
low-grade gypsum ore prior to processing. Ninety percent of all
gypsum ore is calcined into gypsum products including wall board,
lath, building plasters and tile. The remaining 10 percent is
used as land plaster for agricultural purposes and in cement.
The manufacture of gypsum products is not covered in this report.
The cutoff out point between gypsum processing and gypsum
products is just prior to calcination.
Thirty-six companies mined crude gypsum at 65 mines in 21 states
in 1972. Five major companies operate 32 mines from which over
75 percent of the total crude gypsum is produced. Based on 5
facility visits and 36 facility contacts (63% of the total), the
industry was divided into the following sutcategories:
(1) Dry
(2) Wet scrubbing
(3) Heavy media separation
The facilities studied were in all regions of the nation
representing various levels of yearly production and age. The
different methods of processing are shown in Figure 20.
DRY PROCESS
Underground mining is carried out in most mines by the room-and-
pillar method, using trackless mining equipment. In guarrying,
stripping is accomplished both with draglines and tractors.
Quarry drilling methods are adapted to meet local conditions.
Low-density, slow-speed explosives are employed in blasting.
Loading is commonly done with diesel or electric shovels.
Transportation may be by truck or rail from quarry to facility.
Primary crushing is done at most guarries using gyratory and jaw
crushers and impact mills. Secondary crushing is usually
accomplished by gyratory units, and final crushing almost
exclusively by hammermills. The common unit for grinding raw
gypsum is the air-swept roller mill. Ground gypsum is usually
termed "land plaster" since in this form it is sacked or sold as
bulk for agricultural purposes.
No process water is used in the mining, crushing, or grinding of
gypsum. However, mine or quarry pumpout is necessary in a number
of facilities. Pumpout is not related to a production unit of
gypsum, and the flow is independent of facility processing
capacities. Most pumpouts are controlled with a pit or low-area
sump which discharges when the water level reaches a certain
108
-------
FIGURE 20
VENT
t
DRY
DUST
COLLECTOR
A
MINE
OR
QUARRY
PRIMARY
AND
SECONDARY
CRUSMWC
GRINDING
i
PIT PUWPOUT
1
• PRODUCT
GYPSUM MINING AND PROCESSING
(DRY)
RECYCLE
WATER
HCCYCLE
WATER
RECYCLE
WATER
SCREEN
AND
WASH
1
POS'D
1
1
SUMP
tflTAtfY
VEDiA
SEPARATION
' I
WASH
I ,
1i
MiDIA
RECOVERY
•PRODUCT
RECYCLE
TO FACCESS
GYPSUM MINING Afs'D PROCESSING
(HM3)
109
-------
height. Incidental water use includes non-contact cooling water
for crusher bearings.
WET SCRUBBING
Since the completion of the contractor's study, all gypsum
processing facilities have either changed to dry dust collection
systems or employ total containment/recycle systems.
HEAVY MEDIA SEPARATION
Two facilities at the same general location beneficiate crude
gypsum ore using heavy media separation (HMS) prior to
processing. Both facilities follow the same process which
includes quarrying, primary and secondary crushing, screening and
washing, heavy media separation, washing, processing of float
gypsum ore and stockpiling of sink dolomitic limestone.
Magnetite and ferrous silica are used in both facilities as the
separation media, with complete recirculation of the media or
pulp.
Facility 1100 uses 1270 1/kkg (305 gal/ton) of ore processed in
heavy media separation screening and washing which accounts for
all process water. Additional water includes quarry pumpout.
During periods of heavy rainfall, a discharge of up to 189,000
I/day (50,000 GPD) of quarry sump water may occur. As is typical
with quarry pumpout, discharge is controlled by a sump, located
at the low end of the quarry. Facility 1100 does not use non-
contact cooling water for gypsum teneficiation.
110
-------
ASPHALTIC MINERALS (SIC 1U99)
This category of materials encompasses three basic types of
materials produced by three different processes: bituminous
limestone which is dry quarried; oil impregnated diatomite
produced by dry methods; and gilsonite and other bituminous
shales produced by wet processes. The processing of these
minerals are depicted in Figure 21.
BITUMINOUS LIMESTONE
Bituminous limestone is dry surface mined, crushed, screened and
shipped as product.
OIL IMPREGNATED DIATOMITE
This material is produced at only one site (facility 5510). Oil
impregnated diatomite is surface mined, crushed, screened and
then calcined (burned) to free it of oil. The calcined material
is then ground and prepared for sale. The only process water
usage is a wet scrubber used to treat the vent gases from the
calcination step. The scrubber waters are recycled.
GILSONITE
Gilsonite is mined underground. The ore is conveyed to the
surface as a slurry and separated into a gilsonite slurry and
sand, which is discarded as a solid waste. The gilsonite slurry
is screen separated to recover product. Further processing by
centrifuge and froth flotation recover additional material.
These solids are then dried and shipped as product. Water use at
facility 5511 is given below. A considerable amount of intake
water is used for non-process purposes (i.e., drinking and
irrigation). All process and mine pumpout waters are currently
discharged.
1/kkg of product (gal/ton)
intake 5,700 (1,400)
process 3,400 (820)
mine pumpout U70 - 1,800 (110-U30)
drinking and
irrigation 2,300 (550)
111
-------
FIGURE 21
SIPrACE
i;
-------
ASBESTOS AND WOLLASTONITE
ASBESTOS (SIC 1U99)
Processing of asbestos ore principally involves repeated
crushing, fiberizing, screening, and air separation. Five
facilities mine and process asbestos in the United States, four
process by dry methods the fifth by wet methods. Figure 22 shows
the different methods of processing.
ASBESTOS, DJRY PROCESS
Asbestos ore is usually extracted from an open pit or quarry. At
three facilities the fiber-bearing rock is removed from an open
pit. At facility 1061 the ore is simply "plowed", allowed to
air-dry, and the coarse fraction is screened out from the mill
feed. After quarrying, the asbestos ore containing approximately
15% moisture is crushed, dried in a rotary dryer, crushed, and
then sent to a series of shaker screens where the asbestos fibers
are separated from the rock and air classified according to
length into a series of grades. The collection of fibers from
the shaker screens is accomplished with cyclones, which also aid
in dust control. Asbestos processing involves fiber
classification based on length, and as such, the raw waste loads
consist of both oversize rock and undersize asbestos fibers which
are unusable due to their length (referred to as "shorts"). At
facility 1061 28 percent of the asbestos ore is rejected as
oversize waste. At the processing facility another 65 percent of
the feed are unusable asbestos fiber wastes which must be
disposed of.
No process water is used for the dry processing of asbestos at
any of the four facilities in this subcategory. Facility 3052
must continuously dewater the quarry of rain and ground water
that accumulates. The flow is from 380 1/min to 2270 1/min (100
to 600 gal/min)depending on rainfall. The quantity of discharge
is not related to production rate of asbestos. Facility 1061
uses water for dust suppression which is sprayed onto the dry
asbestos tailings to facilitate conveying of tailings to a waste
pile. The water absorbed in this manner amounts to 17 1/kkg of
tailings (U gal/ton) .
113
-------
FIGURE 22
QUARRY I— s>
PRIMARY
CRUSHER
PUVPOUT CVER3IZE
WASTE
—OS
DRY
DUST
COLLECTOR
I
DRY
DUST
COLLECTOR
L. . T r
DRY
SECONDARY SCREEN
^^ Cr.UCHER ^^ omtfcN
— c>
GRADE
WATER cJ
WASTE
FINES
PRODUCT
ASBESTOS MINING AND PROCESSING
(DRY)
VENT
WASTE DUMP
• PRODUCT
ESPECIAL PRODUCT
ASBESTOS MINING AMD PROCESSING
(WET)
111*
-------
ASBESTOS, WET PROCESS
The only facility in this sufccategory, facility 1060, mines the
asbestos ore from a quarry located approximately 50 miles from
the processing facility. The ore is "plowed" in horizontal
benches, allowed to air-dry, screened and transported to the
facility for processing. Processing consists of screening, wet
crushing, fiber classification, filtering, and drying. Process
water is used for wet processing and classifying of asbestos
fibers. Facility 1060 uses 4,300 1/kkg (1,025 gal/ton) of
asbestos milled. Approximately 4 percent of the water is
incorporated into the end product which is a filter cake of
asbestos fibers (5Q% moisture by weight). Eight percent is lost
in the tailings disposal. Sixty eight percent is recirculated
back into the process, and 20 percent is eventually discharged
from the facility. The following tabulates estimated process
water use at facility 1060:
1/kkg gal/ton
of feed of feed
process water 4,300 1,025
water lost with product 150 36
water lost in tailings 350 8U
water recirculated 2,900 700
water discharged to
settling pond 860 205
This facility is unable to recirculate the water from the
settling pond because of earlier chemical treatment given the
water in the course of production of a special asbestos grade.
The recirculation of this effluent would affect the guality of
the special product. In addition to process water, facility 1060
uses 2,100 1/kkg of feed (500 gal/ton) of non-contact cooling
water, none of which is recirculated.
WOLLASTONITE (SIC 1499)
There is only one producer of wollastonite in the U.S. (facility
3070). Wollastonite ore is mined by underground room and pillar
methods, and is trucked to the processing facility. Processing
is dry and consists of 3 stage crushing with drying following
primary crushing. After screening, various sizes are fed to
high-intensity magnetic separators to remove garnet and other
ferro-magnetic impurities. The purified wollastonite is then
ground in pebble or attrition mills to the desired product sizes.
A general process diagram is given in Figure 23. Municipal water
serves as the source for the sanitary and non-contact cooling
water used in the facility. This amounts to 235 1/kkg of product
(56 gal/ton) .
115
-------
MINE
— o
CRUSH
AND
SCREEN
DRY
CRUSH
AND
SCREEN
MAGNETIC
SEPARATORS
_
MILL
AND
CLASSIFY
PRODUCT
WASTEPILE
FIGURE 23
Yi/OLLASTONlTE MINING AND PROCESSING
-------
LIGHTWEIGHT AGGREGATE MINERALS (SIC 1499)
PERLITE
New Mexico produces 87 percent of the U.S. crude perlite. Three
of four major perlite producers in New Mexico were inspected.
All U.S. perlite facilities are in the same geographic region,
and the processes are all dry. All the operations are open pit
quarries using either front-end loaders or blasting to remove the
ore from the quarry. The ore is then hauled by truck to the
mills for processing. There the ore is crushed, dried, graded
(sized), and stored for shipping. A general process diagram is
given in Figure 24.
Perlite is expanded into lightweight aggregate for use as
construction aggregate, insulation material, and filter medium.
Expansion of perlite is done by injection of sized crude ore into
a gas- or oil-fired furnace above 760°C (1,400°F). The desired
temperature is the point at which the specific perlite being
processed begins to soften to a plastic state and allows the
entrapped water to be released as steam. This rapidly expands
the perlite particles. Horizontal rotary and vertical furnaces
are commonly used for expanding perlite. In either case, there
is no process water involved. Horizontal rotary furnaces
occasionally require non-contact cooling water for bearings.
Facility 5500 does dewater the quarry when water accumulates, but
this water is evaporated on land.
The oversize materials, processing and baghouse fines are hauled
to the mine areas and land-disposed. There is work being done by
facilities 5501 and 5503 to reclaim further product grades from
the waste fines. Facility 5501 is investigating the use of water
to make pellets designed to make land-disposal of fines easier
and more efficient.
PUMICE
Pumice is surface mined in open pit operations. The material is
then crushed, screened, and shipped for use as either aggregate,
cleaning powder or abrasive. A process flowsheet is given in
Figure 24. At most operations, no water is employed. This is
true for facilities 1702, 1703, 1704, 5665, 5667 and 5669. At
facility 1701 a small amount of water (10.55 1/kkg product) is
used for dust control purposes, but this is absorbed by the
product and not discharged. At facility 1705 a wet scrubber is
used for dust control purposes.
117
-------
FIGURE 24
VENT
PRODUCT
RODUCT
PERLITE MINING AND PROCESSING
SURFACE
MINING
pmoucr
PUMICE MININ3 AND PROCESSING
OPEN
PIT
MINE
GRIN'D,
\WS.H
AND
CCREEN
MAKE-UP WATER S»
•r
FLOTATION
RECYCLE
i
.
DRY
1 ,
RECYOE 1
SCREEN
RECYCLE
PCNDS
VEfvMiCULITC MINING AND PROCESSING
118
-------
VERMICULITE
The mininq of vermiculite at facility 5506 is conducted by bench
quarrying using power shovels and loaders. Occasionally blasting
is necessary to break up irregularly occurring dikes of syenite.
Trucks then haul the ore to the process facility. The
vermiculite is concentrated by a series of operations based on
mechanical screening and flotation, a new process replacing one
more dependent on mechanical separations. Sizer screens split
the raw ore into coarse and fine fractions. The fines are
washed, screened, and floated. After another screening the
product is dewatered, dried and sent to the screening facility at
another location. The coarse fraction is re-screened and the
fines from this screening are hydraulically classified. Coarse
fractions from screening and classification are sent to a wet
rod-processing operation and recycled. The coarsest fraction
from the hydraulic classification becomes tailings. The fines
from hydraulic classification are screened, floated, re-screened
and sent to join the other process stream at the dewatering
stage.
The mining of vermiculite at facility 5507 is conducted by open
pit mining using scrapers and bulldozers to strip off the
overburden. The ore is then hauled to the facility on dump
trailer-tractor haul units. The overburden and sidewall waste is
returned to the mine pit when it is reclaimed. The vermiculite
ore is fed into the process facility where it is ground and
deslimed. The vermiculite is then sent to flotation. After
flotation, the product is dried, screened, and sent to storage
for eventual shipping. Figure 2<* is a flow diagram showing the
mininq and processing of vermiculite.
Facility 5507 uses surface springs and runoff as source and
make-up water. At facility 5506, water from 2 local creeks
provides both source and make-up water for the vermiculite
operations. In dry weather a nearby river becomes the make-up
water source. A well on the property provides sanitary and
boiler water. Since the only water loss is through evaporation
during drying operations and some unknown amount is lost through
seepage from the ponds to ground water, the net amount of make-up
water reflects this loss. There is also some water loss in
processing.
At facility 5506 waste is generated from the two thickening
operations, from boiler water bleed, and from the washdown stream
that is applied at the coarse tails-solids discharge point.
(This is used to avoid pumping a wet slurry of highly abrasive
pyroxenite coarse solids.) At facility 5507, there is one waste
stream from the desliming, flotation and drying operations. This
stream consists of mineral solids, principally silicates such as
actinolite, feldspar, guartz, and minor amounts of tremolite,
talc, and magnetite (1,600 kq/kkg product).
119
-------
MICA AND SERICITE (SIC 1499)
Mica and sericite are mined in open pits using conventional
surface mining techniques. Sixteen significant U.S. facilities
producing flake, scrap or ground mica were identified in this
study. Six of these facilities are dry grinding facilities
processing either mica obtained from company-owned mines or
purchased mica from an outside supplier. Three facilities are
wet grinding facilities, and seven are wet mica beneficiation
facilities utilizing froth flotation and/or spirals,
hydroclassifiers and wet screening techniques to recover mica.
Additionally there are four known sericite producers in the U.S.
Three of these companies surface mine the crude ore for brick
facilities and a fourth company has a dry grinding facility and
sells the sericite after processing. Figure 25 shows the various
methods of processing.
DRY GRINDING OF MICA AND SERICITE
Dry grinding facilities are of two types, those which process ore
obtained directly from the mine and others which process
beneficiated scrap and flake mica. The ore from the mine is
processed through coarse and fine screens before processing. The
wastes generated from the two screening operations consist of
rocks, boulders, etc., which are bulldozed into stockpiles. The
crude ore is next fragmented, dried and sent to a hammer mill.
In those facilities which process scrap and flake mica, the feed
is sent directly into the hammer mill or into a pulverizer. In
both types of facilities, the milled product is passed through a
series of vibrating screens to separate various sizes of product
for bagging. The waste material from the screening operations
consists of quartz and schist pebbles.
In some facilities either the screened ore or the scrap and flake
mica is processed in a fluid energy process facility. The ground
product, in these facilities, is next classified in a closed
circuit air classifier to yield various grades of products. Dry
grinding facilities utilize baghouse collectors for air pollution
control. The dust is reclaimed from these collectors and
marketed.
WET GRINDING OF MICA AND SERICITE
In a typical wet grinding facility, scrap and flake mica is batch
milled in a water slurry. The mica rich concentrate from the
process facility is decanted, dried, screened, and then bagged.
The mica product from these facilities is primarily used by the
paint, rubber, and plastic industries. The tailings from the
process facility are dewatered to remove the sand. The effluents
emanating from the decanting and dewatering operations constitute
the waste stream from the facility. At one facility visited the
scrap and flake mica is processed in a fluid energy process
120
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FIGURE 25
LEGEND:
SCRAP AW IMC KKt
MICA MINING AND PROCESSING
fDRY)
SCRAP MICA—*.
WATCT
WHTEK-
GRjr.'O'N'S
W.LLS
RIFFLE
LAUNCcR
1
UICA
PTOOUCT
WATER RECYCLED
TO GRINDING KILLS
MICA MINING AND PROCESSING
(V/ET)
rionrioN
SPt-AL
CENTRIFUGE
tMCA MINING AND PKOCS'SSING
(FLOTATION Cn SPIRAL SEPARATION)
121
-------
facility using steam. The waste streams emanating from the
boiler operations are sludge generated from the conventional
water softening process, filter backwash, and boiler blowdown
wastes.
Facilities 2059 and 2055 consume water at 4,900 and 12,500 1/kkg
product (1,300 and 3,000 gal/ton), respectively. At facility
2055, about 80 percent of the water used in the process is
make-up water, the remainder is recycled water from the decanting
and dewatering operations. At facility 2059 makeup water is
1,500 1/kkg of product (360 gallons/ton); the remainder is
recycled from the settling pond.
WET BENEFICIATION PROCESS OF MICA AND SERICITE
These ores contain approximately 5 to 15 percent mica. At the
beneficiation facility, the soft weathered material from the
stockpiles is hydraulically sluiced into the processing units.
The recovery of mica from the ore reguires two major steps,
first, the coarse flakes are recovered by spirals and/or trommel
screens and second, fine mica is recovered by froth flotation.
Five of the seven facilities discussed below use a combination of
spiral classifiers and flotation techniques and the remaining two
facilities use only spirals to recover the mica from the crude
ore. Beneficiation includes crushing, screening, classification,
and processing. The larger mica flakes are then separated from
the waste sands in spiral classifiers. The fine sand and clays
are deslimed, conditioned and sent to the flotation section for
mica recovery. In facilities using only spirals, the underflow
is screened to recover flaked mica. In both types of facilities,
the mica concentrate or the flake mica is centrifuged, dried, and
ground.
Although all flotation facilities use the same general processing
steps, in some facilities, tailings are processed to recover
additional by-products. Facility 2050 processes the classifier
waste stream to produce clays for use by the brick industry and
also processes the mica flotation tailings to recover feldspar.
Facilities 2052 and 2057 process the classifier waste to recover
a high grade clay for use by the ceramics industry.
The water used in these facilities is dependent upon the quantity
and type of clay material in the crude ore. These facilities
consume water at 69,500 to 656,000 1/kkg (16,700 to
157,000 gal/ton) of product. The hydraulic loads of these
facilities are summarized as follows:
122
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Process Water Used
Facility
2050
2051
2052
2053
205U
2057
2058
Facility
1/kkg of product
95,200
240,000
125,000
110,000
69,500
143,000
656,000
Other Water Consumption
gal /ton
22,800
57,600
30,000
26,400
16,700
34,000
157,000
1/kkq of product (gal/ton)
process discharge loss due evaporation.
percolation and
spills
2050
2051
2052
2053
2054
2057
2058
none
none
75,200 (18,000)
none
69,500 (16,7CO)
86,000 (20,600)
none
negligible
negligible
50,600 (12,100)
80 (20)
57,000 (13,700)
The raw waste load in these facilities consists of mill tailings,
thickener overflow, and wastes from the various dewatering units.
In some facilities, waste water from wet scrubbing operations is
used for dust control purposes. The raw waste loads for these
facilities are given as follows:
123
-------
Clay, slimes, mica fines and sand wastes
Facility kg/kkg of product (lb/1000 Ibl
2050 600
2051 14,400
2052 2,600
2053 4,000
2054 4,700
2057 2,900
2058 6,300
124
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BARITE (SIC 1472)
There are twenty-seven significant U.S. facilities producing
either barite ore or ground barite. Nine of these facilities are
dry grinding operations, fourteen use log washing and jigging
methods to prepare the ore for grinding and four are wet
flotation facilities using froth flotation technigues for the
beneficiation of the washed and/or jigged ore. Figure 26 depicts
the different types of processing.
BARITE (DRY PROCESS)
The methods used in grinding barite depend upon the nature and
condition of the ore to be ground and upon the application for
which the mineral is to be sold. In a dry grinding mill, the ore
from stockpiles is batched in ore bins. In most facilities the
ore is soft and crushing is not necessary prior to the milling
operation. In other cases, the ore is hard and must be crushed
before grinding to free barite from the gangue material. After
milling, the ground ore passes through a cyclone and a vibrating
screen before being pumped into the product silos. From here it
is either pumped to bulk hopper cars or to the bagging facility.
The only waste is dust from baghouse collectors which is handled
as a dry solid. No water is used in dry grinding facilities.
There is no pumping of mine water in this subcategory.
BARITE - WET PROCESS (LOG WASHING AND JIGGING OPERATIONS)
The wet processing facilities use washers or jigs to remove the
clay from the barite ore. The mined ore is soft and is passed
through a breaker and then fed to a log washer. The washed ore
is next screened in a trommel circuit, dewatered and then jigged
to separate gravel from the barite product.
In facility 2013, the ore is first processed on a trommel screen
to separate the fines (-3/4" material). The +1 1/2" material is
then crushed and the resulting -1" barite product is sent to the
stockpile. The +3/1 to 1 1/2" material is processed by jigging
to separate gravel from the barite product.
In all these facilities, barite is mined in dry open pits. In
most facilities, the clay strata is excavated by power shovel or
dragline and hauled to the washing facility by dump trucks. In
facility 2013, the barite and the waste (chert) is separated in
the pit by a dozer, the ore is then dried in place, and the fines
are separated by means of a trommel. Several caterpillar dozers
with rippers are used to excavate and push the ore into piles to
be loaded and hauled to the crusher at the processing facility.
The quantity of the clay, sand and gravel, and rock in the ores
mined in these facilities varies from location to location. The
pure barite amounts to 3-7 percent by weight of the material
125
-------
FIGURE 26
ORE
ORE-
1
Cr'_
. CRUSHING J 0':
CIRCUIT
c
SOI 10
ViASTE
MAXE-U1
F
BREAKER — «• ^5^
SOLID WASTE WASTE
TO
STTTI 1KB POND
r"-';
wz _ _ |
"'" *l ccr-v/
i-f.TOR (/ \VLYC?
r»i -
't
,,-,V',:,D J
rEBSLE Cl CYCLOME
an 'IT ""^ -
""" SCREEN
BARITE MINING AND PROCESSING
(DRY GRINDING PROCESS)
> WATER AND RECYCLED WATER
ROM THE TAILINGS POND
• ,
; ;
~* ™CREENL — °EWATER -* J1GS
, ~l
SOLID WASTE WASTE [_
SETTLING POND
BULK
>7C/DJCT
< . ._ r> EULK
^ PR50UCT
Vll VF PRDDUCT
r'f.C.'.E.T LOAD N3
1
DUST
COLLECTOR
\
V/ATcR TO
SETTLING PONO
-««| DrAATER j to 6RAV
WATER
TO
SETTUNC PONO
ORE-
BARITE MINING AND PROCESSING
(V;ET PROCESS)
WATER y»ATW
AND
Vr'ASH
JIG
J
rfLl
SOLID SLII.-E ORA.'EL SLIME
WASTE SALVA5E TO SALVAfS
WASTE
STEAM WATER
K«"ENTS \
flLTKATE
>. BARiTE
PROOUST
FLOTATION
SECTION
1
TWCXENINS
CIRCUIT
FILTER,
DRY
ANO
COOL
— PRO^T
TAIL1NI5S PONS
BAFxITE MNING ANO PROCESSING
(FLOTATION PROCESS)
126
-------
mined. Some waste material is removed at the mine site without
use of water.
The quantity of the water used in these facilities depends upon
the quality of the ore and the type of the waste material
associated with the ore as qiven as follows:
water consumption in 1/kkq
of product (gal/ton)
barite recovery sanitary and
Facility from feed (%} process water misc. usage
2011 63 62,600 (15,000) 650 (150)
2012 63 110,200 (33,600)
2013 77 7,200 (1,725)
2015 5.7 162,700 (39,000)
2016 4.8 239,400 (57,400)
2017 3.3 291,300 (69,800) 12,380 (3,270)
2018 3.9 246,500 (59,100) 8,382 (2,215)
2020 54 62,600 (15,000) 650 (150)
2046 63 140,200 (33,600)
The exceptional facility in the above table is 2013. This
facility uses water at an average of only 7,200 1/kkg product
(1,725 qal/ton) because only 30-40 percent of the ore qoes
through jigging. The majority of the barite at this facility is
dry ground. In facilities 2012, 2013 and 2046, the process water
volumes given include the water used for sanitary purposes. In
all facilities, the process water is recycled. Makeup water may
be required in some of these facilities.
The process raw wastes in this subcategory consist of the mill
tailings from the washing and jigging circuits. These clay and
sand wastes range from 230 to 970 kg per kkg of feed.
BARITE (FLOTATION PROCESS)
Processing in these facilities consists of crushing the ore to
free it from the gangue material, washing the barite ore to
remove the clay, jigging the washed ore to separate the gravel,
grinding, and beneficiation by froth flotation to recover barite
concentrates. The concentrates are then filtered and dried.
Drying is at temperatures high enough to destroy the organic
reagent used in the flotation. The dried product is then cooled
and bagged for shipment. At facility 2019, two separate
flotation circuits are used to recover barite fines from the log
washer and jig tailings. In facility 2014, the ore from the mine
is free from clays and sands, and this facility processes its ore
without a washing and jigging operation.
127
-------
The ma-jor process raw waste emanating from these facilities is
the flotation mill tailings. The solids in the raw waste stream
was reported to be an average of 24,750 mg/1 and maximum of
50,000 mg/1 for facility 2019. The quantities of the wastes are
given as follows:
Facility
Mill tailings
Washdown water
from mill
Spent brine from
water softening
operation
I/day (gal/day)
2010
530,000
(140,000)
265,000
(70,000)
2014
660,000
(173,500)
110,000
(29,000)
19,000
(5,000)
2019
4,730,000
(1,250,000)
unknown
Facility 2010 consumes water at an average of 45,000 1/kkg
product (10,800 gal/ton) on a total recycle basis. This includes
about 1,655 1/kkg product used for non-contact cooling, boiler
feed and sanitary purposes. Most of the process water used in
this facility, 13,025,000 I/day (3.44 mgd), is recycled back to
the facility from the thickening operations. At facility 2014,
well water is used both in the flotation circuit and for the
milling operation. This facility consumes 2,500 1/kkg of product
(595 gal/ton). Approximately 35 percent of this water is
recycled from the thickening operations. The flotation tailings
and some overflow from the thickener are sent to the tailings
pond. At facility 2019 untreated river water is used as process
water. This facility consumes an average of 33,700 1/kkg of
product (8,900 gal/ton) on a once through basis. The hydraulic
load of these facilities are given as follows:
128
-------
Facility
Makeup water
Recycled water
Process consumed
Non-contact
cooling
Sanitary
Boiler feed
I/day (gal/day)
2010
2,725,000 max.
(720,000 max.)
13,025,000
(3,440,000)
15,750,000
(4,160,000)
530,000
(140,000)
37,900
(10,000)
37,900
(10,000)
Brine & back flush
Srinse water used
in water softening
Misc. housekeeping
2014
792,000
(208,980)
427,000
(112,520)
872,000
(230,000)
218,000
(57,500)
19,000
(5,000)
110,000
(29,000)
2019
4,731,000
(1,250,000)
4,731,000
(1,250,000)
129
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FLUORSPAR (SIC It73)
There are fifteen significant facilities in the U.S. producing
either fluorspar concentrates and/or finished acid grade and
metallurgical grade fluorspar products. Six of these facilities
are wet heavy media separation (HMS) facilities, producing both a
finished product (metallurgical gravel) and upgraded and
preconcentrated feed for flotation. Five facilities use froth
flotation for the production of fluorspar alone or with barite,
zinc, or lead; three are fluorspar drying facilities drying
imported filter cakes in kilns or air driers, and one is a
fluorspar pelletizing facility, where spar filter cake is pressed
to pellets, dried and shipped. Figure 27 shows the different
methods of processing.
FLUORSPAR - HEAVY MEDIA SEPARATION (HMS) OPERATIONS
An HMS facility may serve two purposes. First, it upgrades and
preconcentrates the ore to yield an enriched flotation feed.
Second, it produces a metallurgical grade gravel. The ore is
crushed to proper size in the crushing circuit, then washed and
drained on vibrating screens to eliminate as many fines as
possible. The oversize material from this operation is recycled
back to the screen. The undersize is sent into a spiral
classifier for recovery of a portion of the flotation facility
feed. The HMS cone feed consists of the middle size particles
resulting from the screening operation. The separatory cone
contains a suspension of finely ground ferro-silicon and/or
magnetite in water, maintained at a predetermined specific
gravity. The light fraction (HMS tailings) floats and is
continuously removed by overflowing a weir. The heavy particles
(flotation feed) sink and are continuously removed by an airlift.
The float overflow and sink airlift discharge go to drainage
screens where 95 percent of the medium carried with the float and
sink drains through the screen, is magnetically separated from
the slimes, and is returned to the circuit. The float and sink
products are passed over dewatering screens and the water is
pumped back to the facility.
Water consumption in these facilities ranges from 96 to 2700
1/kkg of feed to the facility (650-2300 gal/ton of feed). The
hydraulic loads for the HMS facility were not known in two of the
facilities (2008 and 2009) because the HMS and flotation
facilities are located at the same site. They are operated as a
combined unit and water consumption values were available for the
combined operation. The hydraulic loads for the remaining
facilities are given as follows:
130
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FIGURE 27
FLOTATION
FEED
CRUSHING
AND
RECYCU
WATER
CRUSHING FOfi
AN3 RECYCLE
RECYCLE
LEGEND:
OVfRjIZE
UNOERSIZE
FLUORSPAR MINING "AND PROCESSING
(HMS PROCESS)
PROOOCT
ZINC BY-PRODUCT
WATER
FOR
RECOVERY
FLUORSPAR IWNING AND PROCESSING
(FLOTATION PROCESS)
131
-------
Water Consumption 1/kkq of feed (gal/ton)
Facility 2004 2005 2006 2007
9,600 2,710 3,670 5,550
(2,300) (650) (880) (1,330)
Raw wastes in this subcategory consist primarily of slimes from
fines separation. At five of the facilities in this subcategory
(facilities 2004, 2005, 2006, 2008 and 2009), there is no waste
discharge from the HMS process. The water used in these
facilities is recycled back through closed circuit impoundments.
At facility 2007 the raw waste, consisting of the classifier
overflow is discharged into a settling pond prior to discharge.
The average value of the raw slime waste for facility 2007 is 340
kg/kkg of product.
FLUORSPAR-FLOTATION OPERATIONS
There are currently five fluorspar flotation mills in operation
in the U.S. Three of these operations are discussed below. A
fourth facility is in the startup stage and operating at
30-40 percent of design capacity.
In froth flotation facilities, fluorspar and other valuable
minerals are recovered leaving the gangue minerals as mill
tailings. Facility 2000 recovers fluorspar, zinc and lead
sulfides. Facility 2003 recovers fluorspar only. At facilities
2000 and 2001, lead and zinc sulfides are floated ahead of
fluorspar using appropriate reagents as aerofloats, depressants
and frothers. At facility 2000, barite is floated from the
fluorspar rougher flotation tailings.
In all these facilities, steam is added to enhance the selec-
tivity of the operation. The various grades of concentrates
produced are then stored in thickeners until filtered. Barite,
lead sulfide, and zinc sulfide concentrates are sold in filter
cake form. The fluorspar concentrates are dried in rotary kilns.
The dried concentrates are then shipped. At facility 2001, a
portion of the fluorspar filter cake is sent to the pellet
facility where it is mixed, pressed into pellets, dried and
stored.
The ores have different physical characteristics and require
different quantities of process water. A maximum of 20 percent
of the process water is recycled from the thickeners. The
remainder is discharged into a ponding system. The hydraulic
loads for these facilities are:
132
-------
1/dav fmgd)
Process
Boiler feed
Non-contact cooling
Dust control
Sanitary uses
Process waste
Water recycled or
evaporated
facility water use
process waste
2000
1,700,000
(0.45)
30,000
(0.008)
38,000
(0.010)
120,000
(0.032)
4,000
(0.001)
1,515,000
(0.40)
377,000
(0.103)
2001
3,425,000
(0.905)
54,000
(0.014)
2,500
(0.0008)
3,260,000
(0.865)
196,500
(0.055)
2003
1,090,000
(0.288)
54,500
(0.014)
1/kkg of product (cral/ton)
11,900
(2,860)
9,540
(2,290)
20,200
(4,840)
19,100
(4,580)
1,144,500
(0.302)
21,030
(5,040)
0
The process raw wastes in this sutcategory consist of the
tailings from the flotation sections. At facilities 2000 and
2001, the tailings contain 14 to 18 percent solids, which consist
of 4-5 percent CaF2, 20-25 percent CaCO3, 25-30 percent SiO2, and
the remainder is primarily shale and clay. The average values of
the raw wastes are:
kg/kkg of product
2000 2001
flotation tailings
1,800
2,000
(Ib/lOOO Ib)
2003
2,000
FLUORSPAR (DRYING AND PELLETIZING OPERATIONS)
There are presently three fluorspar drying facilities in the U.S.
In these facilities imported filter cakes are dried and sold.
The filter cake has about 9-10 percent moisture which is dried in
kilns or in air driers. Two of these facilities have no
discharge. They use baghouse collectors for dust control. The
third drying facility is located at the same site as the
company's hydrofluoric acid facility. This drying facility has
an effluent from the wet scrubber on the drier, which is treated
in the gypsum pond along with the acid facility effluent. The
133
-------
combined effluent stream has teen covered under the Inorganic
Chemical Manufacturing category.
There are two pelletizing facilities in the U.S. One of these
operations has been discussed previously under flotation
(facility 2001). A second facility manufactures fluorspar
pellets only. At this facility fluorspar filter cake is mixed
with some additives, pressed into pellets, dried and stored. No
pollutants are generated at this facility site.
MINE DISCHARGE IN FIUCRSPAR OPERATIONS
There are presently seven fluorspar active mines in the U.S. Six
of these mines are underground operations (2088, 2089, 2090,
2091, 2092 and 2093) and one is a dry open-pit mine (2091).
Additionally, there are three underground mines in the
development stage (2085, 2086, 2087) with no current production
and five other mines with no production but are dewatered (2080,
2081, 2082, 2083 and 208U).
Mine 2080 is used as an emergency escape shaft, air shaft, and
also to help dewater mine 2088. There are no discharge waters
pumped from either mines 2081 and 2087. What water there is in
these mines drains underground and eventually enters mine 2083.
It has keen estimated that mine 2085 will have a discharge volume
in the vicinity of 3,800,000 I/day (1 mgd). The present
discharge is only a small fraction of the anticipated volume of
water from this mine. At mines 2091 and 2093, about 62 and
UO percent, respectively, of the mine discharge water is used at
the mills. The remaining drainage is then discharged.
134
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SALINES PROM ERIN! LAKES (SIC 14710
The extraction of several mineral products from lake brines is
carried out at three major U.S. locations: Searles Lake,
California; Silver Peak, Nevada; and the Great Salt Lake, Utah.
The operations at these locations are integrated and the water
and waste handling cannot be readily attributed to the separate
products. The facilities at Searles Lake operate what is called
the "Trona Process", not to be confused with the trona ore mining
in Sweetwater County, Wyoming, discussed elsewhere. This complex
process produces many products based on the brine constituents.
The process operated at the Great Salt Lake produces a smaller
number of products. However, the waste handling and disposal
techniques at all locations are quite similar.
SEARLES LAKE OPERATIONS
Several minerals such as borax, lithium salts, salt cake, natural
soda ash and potash are produced from the brine of Searles Lake,
California, by a series of processing steps involving evaporation
of the brine in stages with selective precipitation of specific
ingredients. The recovery processes and raw material are unique
to this location. These processes are carried out in a desert
area adjacent to Searles Lake, a large residual evaporate salt
body filled with saline brines. About 14 percent of the U.S.
potash production is from this source, TH percent of the U.S.
natural sodium sulfate, 17 percent of the U. S. borax, and 12
percent of the natural soda ash.
At facility 5872, the brines are the raw material and are pumped
into the processing facilities where the valuable constituents
are separated and recovered. The residual brines, salts and end
liquors including various added process waters are returned to
the lake to maintain the saline brine volume and to permit
continued extraction of the valuable constituents in the return
water. There is no discharge as the recycle liquors are actually
the medium for obtaining the raw material for the processes.
Total brine flow into the facility is about 33,600,000 I/day
(9,0 mgd) with about one quarter being lost by evaporation. The
total recycle back to the salt body is the same volume, including
added process waters.
For potash production at Searles Lake, a cyclic evaporation-
crystallization process is used in which about 16,350,000 I/day
(1.32 mgd) of saline brine are evaporated to dryness. The brine,
plus recycle mother liquor, is concentrated in triple effect
steam evaporators to produce a hot concentrated liguor high in
potassium chloride and borax. As the concentration proceeds,
large amounts of salt (NaCl) and burkeite (Na2CO.3, Na2!SOtt) are
crystallized and separated. The former is returned to the salt
body and the latter, which also contains dilithium sodium
phosphate is transported to another process for separation into
135
-------
soda ash (Na2icq3) , salt cake (Na2SO4) , phosphoric acid and
lithium carbonate. The hot concentrated liquor is cooled rapidly
in vacuum crystallizers and potassium chloride is filtered from
the resulting slurry. Most of the potassium chloride is dried
and packaged while a portion is refined and/or converted into
potassium sulfate. The cool liquor, depleted in potassium
chloride, is held in a second set of crystaliizers to allow the
more slowly crystallizing borax to separate and be filtered away
from the final mother liquor which is recycled to the
evaporation-concentration step to complete the process cycle.
The borax, combined with borax solids from the separate
carbonation-refrigeration process, is purified by
recrystallization, dried, and packaged. A process flow sheet is
given in Figure 28.
The wastes from the basic evaporation-crystallization process,
including the processes for potassium chloride, borax, soda ash,
and salt cake, are weak brines made up of process waters, waste
salts and end liquors. These are returned to the salt body in an
amount essentially equal to the feed rate to the process—about
16,350,000 I/day (U.32 mgd). The recycle liquors enter both the
upper and lower structures of the salt body. In the case of the
carbonation-refrigeration system, the entire brine stream,
depleted in sodium carbonate and borax, is recycled to the salt
body to continue the solution mining. The overall water usage
for the two facilities is about 33,6CO,OOC I/day (8.88 mgd) of
Searles Lake brine with about one-third of this volume of fresh
water used for washing operations.
GREAT SALT LAKE RECOVERY OPERATIONS
At the present time four mineral products are produced at this
location: sodium chloride, sodium sulfate, potassium sulfate and
bittern liquors. Recovery of pure lithium and magnesium salts is
being planned for the future. About 20 percent of the U.S.
natural sodium sulfate comes from this location.
Brine from the north arm of Great Salt Lake is pumped into a
series of evaporation ponds. Partial evaporation occurs
selectively precipitating out sodium chloride. The residual
brine is pumped to a second series of ponds for further
evaporation and the precipitated salts are harvested.
In the second series of ponds, further evaporation of the brine
occurs to precipitate sodium sulfate. The concentrated residual
brine is pumped to a third series of ponds and the sodium sulfate
is harvested. In the third series of ponds, further evaporation
occurs effecting precipitation of potassium sulfate. The
residual brine is then pumped to a fourth series of ponds for
bittern recovery and the potassium sulfate is harvested.
136
-------
A- I 01 «— '
1
WA1U LIOVJC*
i — r
KKY-.TAILIZC
FMER
], . ,, j^
_,
J WT01/J1
" ] j
_^ liuiR r~" PU" • -• -
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uram t»o«iM— » r . .,.
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i t
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MINERALS RECOVERY FROM SEAF.LES LAKE
CHEAT
SALT
LAKE WASHOUT
ESir.E W4TER
1 :
U.\TCJ_J». m— inivrn •_>. PARTIAL '_
»ATES— •• DISSOLVES •» EVApCPAT|ON j-
EVAPORATION EVAPORATION ._, EVAPORATION
POiO
WWTEHOT
3 ^ PONDS PON-OS
1
WATER
- 1
V.'ASHiNS
DRYING
1
ER TO LA*E
i
| EVAPORATION ._ „.
j POfiDS
WCTER
1
*
RASKINS
DRYING
LIQUOR
TO fOND
BITTERN
PR03UCT
PRODUCT
f, Ma. SO,
^ PRODUCT
WASTE V;ATER
TO LAKE
MINERALS RECOVERY AT GREAT SALT LAKE
UJ« LIKE SOM ASH VENT
'ROM WLJ.5 ° Ev';PCRA7IOr
r _t REACTION __ SSCOKOMVr
i PCJ.D "~*" EVAPORATION — "*
1 i
"l'0"1? S'JCIDS
(SOLID VOCTE) (Norl, KCI)
TO STOl ACE
RE*Sr?R FIH^R LITHWM
FILTER DRY PRODUCT11
,L,
(SOL'O W«TE)
LIQCOR
LITHIUM SALT FCCOVERY
NATURAL CHINE, SILVER PEAK OPERATIONS
137
-------
The harvested raw salts are treated in the following manners
prior to shipment:
(a) Sodium chloride is washed with fresh water, dried, and
packaged.
(b) sodium sulfate is treated in the same manner as sodium
chloride.
(c) Potassium sulfate is dissolved in fresh water, recrystallized
from solution, dried, and packaged.
The washwaters from the sodium sulfate and chloride purifications
and waste water from the recrystallization of potassium sulfate
are discharged to the Great Salt Lake. A process flowsheet is
given in Figure 28. There is also some discharge due to yearly
washout of the evaporation ponds with fresh water. These are all
returned to the Great Salt Lake.
Eleven million liters per day (2.9 mgd) of waste water arises
from two sources: washing of the recovered sodium chlorides and
sulfate, and recrystallization of recovered potassium sulfate.
The waste water from these operations contains these three sub-
stances as constituents along with minor amounts of materials
present in lake trine bitterns (i.e., magnesium salts). Since
the waste water constituents are similar to the lake brine, these
wastes are discharged without treatment back to the Great Salt
Lake. The compositions of the intake brine and effluent wash
water are, in terms of mg/1:
lake brine facility discharge
sodium 96,800 33,450
magnesium 49,600 99,840
chloride 160,000 78,000
sulfate 1U,500 55,500
TSS 1945 703
SILVER PEAK, NEVADA, OPERATIONS
This facility manufactures lithium carbonate. Brine containing
lithium salts is pumped to the surface to form a man-made brine
lake. This consists of a series of evaporation ponds for
preliminary concentration. After this step, the brine is then
treated with lime to precipitate magnesium salts as the
hydroxide. The magnesium hydroxide is recovered periodically
from the ponds as a precipitant.
The treated brine is then further concentrated by evaporation to
partially precipitate sodium and potassium salts. These are
periodically harvested from the ponds and stored for future
processing to recover potash values. The concentrated brine is
again reacted with soda ash, and the precipitated lithium
carbonate is filtered, dried, and packaged. The spent brine is
138
-------
returned to the preliminary evaporation ponds for mixing with
fresh material. A process flowsheet is given in Figure 28.
Facility water consists of brine from an underground source and
fresh water used for washout purposes. All of this water is
evaporated during the process and all of the wastes produced as
solids.
1/kkg of product (gal/ton)
Process brine 1,500,000 (360,000)
Process washout water 36,800 (8,500)
139
-------
BORAX (SIC 1474)
The whole U.S. production of borax is carried out in the desert
areas of California by two processes: the mining of borax ore
and the Trona process. This latter process is discussed in
detail in the section on salines from brine lakes. The mining of
ore accounts for about three-fourths of the estimated U.S.
production of borax. The facility discussed herein is the only
U.S. producer by this method.
Borax is prepared by extraction from a dry mined ore which is an
impure form of sodium tetraborate decahydrate (borax). The ore
is crushed, dissolved in water (mother liguor), and the solution
is fed to a thickener where the insolubles are removed and the
waste is sent to percolation- proof evaporation ponds. The borax
solution is piped to crystallizers and then to a centrifuge,
where solid borax is recovered. The borax is dried, screened and
packaged and the mother liquor recycled to the dissolvers. A
process flow diagram is given in Figure 29.
Fresh water consumption at the facility amounts to 2,840 1/kkg
(680 gal/ton). An additional 835 1/kkg (200 gal/ton) enters via
the ore. Most of the cooling water is recycled and all the
process waste water is sent to evaporation ponds.
140
-------
WATER
RECYCLE MOTHER LIQUOR
WATER
VENT
BORAX
PRE
CRUSHER
»K«£3»
1 J
DiSSOLVER
-— {*»
THICKENER
1
!
=—»££•
CRYSTALLIZER
H
CENTRIFUGE
— e*
\
DRYING
AND
SCREENING
WASTE VWTER
• PRODUCT
FIGURE 29
BORATE MiNING AND PROCESSING
-------
POTASH (SIC 117U)
Potash is produced in four different geographical areas by four
different processing methods. These methods are:
(1) Dry mining of sylvinite ores is followed by flotation or
selective crystallization to recover potash as potassium
chloride from the sylvinite and dry mining of langbeinite
ores is followed by leaching to recover potash as langveinite
from the ores. A portion of the leached langbeinite, usually
fines from product screening, is reacted in solution with
potassium chloride to produce potassium sulfate and magnesium
chloride. The latter is either recovered as a co-product or
discarded as a waste. These are the processes employed in
the Carlsbad, New Mexico, area operations.
(2) Solution mining of Searles Lake brines is followed by several
partial evaporation and selective crystallization steps to
recover potash as KC1. During the several process steps, 12
other mineral products are also recovered. This is discussed
earlier.
(3) Solution mining is performed from Utah sylvinite deposits.
This method is used to recover potash as a brine, which is
then evaporated. The solids are separated by flotation to
recover potassium chloride. The sodium chloride is a solid
waste.
(<») Evaporation of Great Salt Lake brines is similar to the
Searles Lake operation in that the brine is evaporated in
steps to selectively recover sodium chloride and sulfate and
potassium sulfate. The latter product is purified by
recrystallization. All of the wastes from this process which
consist of unrecovered salts are returned to the lake. This
is also discussed earlier.
CARLSBAD OEPRATIONS
There are two processes employed in the six Carlsbad area
facilities which account for about 8H percent of the U.S. pro-
duction of potash. One is used for recovery of potassium
chloride and the other for processing langbeinite ores.
Sylvinite ore is a combination of potassium and sodium chlorides.
The ore is mined, crushed, screened and wet ground in brine. The
ore is separated from clay impurities in a desliming process.
The clay impurities are fed to a gravity separator which removes
some of the sodium chloride precipitated from the leach brine and
the insolubles for disposal as waste. After desliming, the ore
is prepared for a flotation process, where potassium and sodium
chlorides are separated. The tailings slurry and the potassium
chloride slurry are centrifuged, and the brines are returned to
the process circuit. These tailings are then wasted, and the
142
-------
sylvite product is dried, sized and shipped or stored. A process
flowsheet is given in Figure 30. Langbeinite is a natural
sulfate of potassium and magnesium, K2Mq2 (SO4)_3, and is
intermixed with sodium chloride. This ore is mined, crushed, and
the sodium chloride is removed ty leaching with water. The
resulting langbeinite slurry is centrifuged with the brine being
wasted and the langbeinite dried, sized, shipped or stored.
A portion of the langbeinite, usually the fines from sizing, are
reacted in solution with potassium chloride to form potassium
sulfate. Partial evaporation of a portion of the liquors is used
to increase recovery. The remaining liquor from the evaporation
step is either wasted to an evaporation pond or evaporated to
dryness to recover magnesium chloride as a co-product. The
disposition of the waste liquor is determined by the saleability
of the magnesium chloride co-product and the cost of water to the
facility. The potassium sulfate slurry from the reaction section
is centrifuged with the liquor returned to the facility circuit,
and the resulting potassium sulfate product is dried, sized,
shipped or stored. A simplified process flowsheet is given in
Figure 30.
All six facilities at Carlsbad processing sylvinite ore are
described above. Two process langbeinite only. One facility
processes langbeinite ore in addition to sylvinite. In that
case, the ore is dry mined, crushed and cold leached to remove
sodium and potassium chlorides. The material is then washed free
of clays, recovered, dried and packaged.
Water use at sylvinite ore processing facilities is shown as
follows:
1/kkg of product (gal/ton)
Facility 5838 5843
input:
fresh water 6,420 (1,540) 1,750 (421)
brine not known 3,160 (760)
use:
process contact 34,600 (8,300) 11,900 (2,900)
cooling 0 0
boiler feed 0 205 (50)
consumption:
process waste 6,420 (1,540) 4,710 (1,130)
boiler blowdown 0 205 (50)
143
-------
FIGURE 30
t
c.-.,.-;:
BPWE PrO'C
V'ATEft
1
!
j *
i j KS.V;;:
| SEFAr'ATE
" i
C&" '^3 SLi"r~
TO tA-iTE TO
LE
FLCT'.riorj
CHi
»
M1C/*I *5
j J
'
FLOTATIDr;
OR WASTE
TO RECYOE
LEGEND:
AUCRIMTC
ROUTES
VENT
t
1
'•
TA'L.''.'3S
VVAjTE
A'.D
ERlfiE
POTASSIUM CHLORIDE MINING AND PROCESSING FROM SYLVIN1TE ORE
POTASSIUM _.
CHLORIDE ^
WTER i>
OISSOLVER
,
FILTRATION
LA.M6BEINITE ORE —
1
V«STI
— e»
MUD
i
s
i
REACTOR
BRINE LIOUOR RECYCLE
SOL'D WASTE
V
\
MAGNESIUM
CLARIFIER e^CHLORiCE
CO-PRODUCT
'APCR
EVAPORATOR
I
1
PARTIAL POTASSIUM
EVAPORATION ° rwaxi
LANGBEWTE MIKirJG A\'D PROCESSING
WATER ">ATCT
'i J
SYLViNITE
DEPOSIT
EVAFORAIiCM
PON'CS
FLOTATION
SEPARATION
DRYING
7
SCDH"^ CftC'lCE
SOLID »ASTE
POTASSIUM
» CHLOR.OE
r-!ODUCT
POTASH RECOVERY BY SOLUTION MINING OF SYLVINITE
144
-------
Water use at langbeinite ore processing facilities is shown
as follows:
1/kkg of product (gal/ton)
Facility 5813 5822
input:
fresh water 8,360 (2,000) 4,800 (1,200)
use:
leaching and washing 5,000 (1,200) 4,800 (1,200)
cooling 30,000 (7,200) 0
consumption:
process evaporation 0-1,670 (400) 0
process waste 0-1,670 (400) 4,800 (1,200)
cooling water evapora- 6,700 (1,600) 0
tion
For sylvinite ore processing, the raw wastes consist largely of
sodium chloride and insoluble impurities (silica, alumina, etc.)
present in the ore. In langbeinite processing the wastes are
insolubles and magnesium chloride. A comparison of the raw
wastes of two sylvinite facilities (facilities 5838 and 5843)
with langbeinite raw wastes (facilities 5813 and 5822) is given
below. Differences in ore grades account for differences in the
clay and salt wastes:
kg/kkg of product (lb/1000 Ib)
Facility 5838 5843
wastes:
clays 75 235
NaCl (solid) 3,750 2,500
NaCl (brine) 1,400 1,000
KCl (brine) 75 318
MgSQ4 640 75
K2SO4 440 0
Facility 5813 5822
A small percentage of the wastes of facility 5838 is sold.
Part of the magnesium chloride from langbeinite processing is
periodically recovered for sale and part of the remaining
brine solution is recycled as process water.
These brines contain about 33 percent solids.
The wastes consist of muds from the ore dissolution and the
wasted brines.
The latter brine can sometimes be used for MgCl2 production
if high grade, low sodium content langbeinite ore is used.
The composition of the brines after K2SO4 recovery is:
145
-------
potassium
sodium
magnesium
chloride
sulfate
water
3.29%
1.3%
5.7%
18.5%
U.9%
66.7%
UTAH OPERATIONS
Solution mining of sylvinite is practiced at two facilities in
Utah. The sylvinite (NaCl, KCl) is solution mined, and the
resulting saturated brine drawn to the surface is evaporated to
dryness in large surface ponds. The dried recovered material is
then harvested from the ponds and separated by flotation into
sodium and potassium chlorides. The sodium chloride tailings are
discarded as a waste and the recovered potassium chloride is then
dried and packaged. A process flowsheet is given in Figure 30.
Fresh water is used for process purposes at facility 5998 in the
following amounts: 10,600,000 I/day (2.8 mgd) and 11,700 1/kkg
(2,8CO gal/ton). Water is used first in the flotation circuit
and then in the solution mining. The resulting brine from these
operations is evaporated and then processed in the flotation
unit. There is no discharge of process water.
146
-------
TRONA (SIC 114714)
All U.S. mining of trona ore (impure sodium sesquicarbonate) is
carried out. in Sweetwater County, Wyoming, in the vicinity of
Green Fiver. The deposits are worked at four facilities. Three
mine trona ore and process it to the pure sodium carbonate (soda
ash). One of these three facilities also produces other sodium
salts using soda ash as a raw material. The fourth facility has
only mining operations at this time, but plans to build a soda
ash processing facility on the site in the near future. The 1973
production of soda ash from these deposits amounted to 3,100,000
kkg (3,400,000 tons). This corresponds to about 5,800,000 kkg of
trona ore mined (6,500,000 tons).
The facility data contained herein are current except for
facilities 5962 and 5976 which are appropriate to the 1971 period
when the discharge permit applications were processed. The trona
ore mining rate in 1971 was approximately 4,000,000 kkg/yr
(4,UOO,000 tons/yr). Rapid expansion in capacity of these
facilities has been taking place in recent years and continues at
this time. Since the mining and ore processing operations are
integrated at these facilities, they are covered as a whole by
this analysis. All four facilities are represented in the data.
The trona deposits lie well beneath the surface of this arid
region and are worked by room and pillar mining or longwall
mining at depths of 240 to 460 m (800 to 1500 ft). The broken
ore is transported to the surface and stockpiled for further
processing. The mining is a dry operation except for leakage
from overlying strata through which the mine shafts were sunk or
from underlying strata under pressure. All four facilities
experience such mine leakage.
The on-site refining process for trona ore consists of its
conversion to the pure sodium carbonate, called "soda ash". The
processing includes the removal of insoluble impurities through
crushing, dissolving and separation, removal of organic
impurities through carbon absorption, removal of excess carbon
dioxide and water by calcining and drying to soda ash. Two
variations of the process are used, the "sesquicarbonate" process
and the "monohydrate" process. At present all three soda ash
refineries use the monohydrate process. One also uses the
sesquicarbonate process. General process flow diagrams of both
processes are shown in Figure 31 with the raw materials and
principal products material balances given in units of kg/kkq
soda ash product.
These processes both require large quantities of process and
cooling water for efficient operation, but the arid climate in
this area (average annual precipitation of 7 to 8 inches) allows
for disposal of waste water through evaporation in ponds.
147
-------
FIGURE 31
WVB» »ftT» INTAKE -* PR|C.' ™TE>
riLTwR
VENT
SCRUBBER
CH
PRECPITATOR
. '~' 1
STCCKP'LE — •• CRUSH — * CALjC'*'r —
1*
M.\S AND PLANT
i
RU::OFF 1
WA7ES VAKE-U> VWSTER
r
MUDS
D:3SOLVE,
CLAftlFY
AND
F.L7ER
c~i-
AO^rris
I£0-J-'O _S~~
1
„„ ... L
CON'EN^E
wiERWPca -TOC-LI:
A"r |
HASN--S23S-C
1
1
1
1
L^- SPENT CAi2CN
| MO FtlCS AI3
1
V'AJW VENT
SCRUE3ER
PRECIPITATOR
anHrucE^^E,
EVAPCSATON PCMJS |
TRONA ORE PROCESSING
BY THE MONOHYDRATE PROCESS
BOO-1320
TRONA CKE~~""1
.1000 SMA
ASHPHOOXT
TRCMA CRE FROCE?S!KG
BY THE SZSQUICARBONAVE PROCESS
-------
Raw wastes from these operations come from three sources: mine
pumpout water, surface runoff and ground water, and ore
processing water. The wastes in the mine and surface water are
principally saline materials (dissolved solids) and suspended
solids. The ore processing raw wastes are principally the
impurities present in the trona ore plus some unrecovered sodium
carbonates, carbon, filter aids, and treatment chemicals as well
as any minerals entering with the makeup water. The average mine
pumpout at these facilities ranges from less than 19 to
1,110 1/min (5 to 500 gpm).
waste materials 5962 5976
(mg/1)
dissolved solids 74,300 11,500
suspended solids 369 40
COD 346 2.1
ammonia 8.1
fluoride 11
lead 0.023
chloride 1,050
sulfate 655
High ground water levels during the March through August period
give a seasonal water flow in the 5962 facility containing 2,160
kg/day (4,750 Ib/day) of total solids, principally dissolved
solids. This particular ground water problem apparently does not
exist at the other facilities. Rainwater and snow runoff
discharges are highly variable and also contain saline dissolved
solids and suspended solids.
Unlike the foregoing wastes, the ore processing wastes are
principally related to the production rate and, hence, are given
on the basis of a unit weight of ore:
waste material kg/kkg of ore (Ib/lCOO Ib)
ore insolubles (shale and shortite) 100-140
iron sulfide (FeS) 0-1
sodium carbonate 60-130
spent carbon and
filter aids (e.g., diatomaceous
earth, perlite) 0.5-2
The composition of the mill tailings water flow from facility
5933 to the evaporation ponds, is:
total dissolved solids: 15,000 mg/1
total suspended solids: 2,000 mg/1
total volatile solids: 2,500 mg/1
chloride: 3,400 mg/1
149
-------
Water use at the mines having attached refineries is determined
principally by the refining process. The only water associated
with the mines is mine pumpout, dust control water and sewage,
the latter two being rather small.
Relative flow per unit production values for the mine pumpout are
not useful since the flow is not influenced by production rate.
There are three major routes of consumption of the water taken
into these facilities: evaporation in the course of refining via
drying operations and cooling water recycling, discharge of waste
water to evaporation ponds (both process and sanitary), and by
discharge of wastes to waterways. The consumption of water for
the three soda ash refiners via these routes is:
total consumption 106 I/day (mqd) 1/kkg of product
(gal/ton)
average 9.3 2,840 (680)
range of averages 7.08-10.6 2,250 - 3,200
(1.9-2.8) (540-760)
evaporation in processing
average 3.4 (0.9) 1,100 (260)
range of averages 3.0-3.8 940 - 1,200
(0.8-1.0) (230-280)
netflow to evaporation ponds
average 5.8 (1.5) 1,800 (430)
range of averages 4.1-6.8 1,300 - 2,000
(1.1-1.8) (320-490)
discharge
average 23,000 (0.006) 8 (2)
range of averages 0-45,000 (0-0.012) 0-13 (0-3)
A significant variation in the above flows during the course of a
year would be the effect of increase in production rate
occasioned by a facility expansion.
150
-------
SODIUM SULFATE (SALT CAKE)
Sodium sulfate (salt cake) is produced from natural sources in
three different geographical areas by three different processing
methods because of differences in the ores or brines utilized.
Salt cake is also recovered as a by-product of numerous inorganic
chemical industry processes. The three mining processes are:
(a) Recovery from Great Salt Lake brines as part of a stepwise
evaporation process. Sodium chloride and potassium sulfate
are recovered as co-products. This process was discussed in
Salines from Brine Lakes.
(b) Recovery from Searles Lake brines as part of an involved
evaporative series of processes which generate 13 products.
This process was also discussed in Salines from Brine Lakes.
(c) Recovery from West Texas brines by a selective
crystallization process.
There are two facilities mining sodium sulfate from brine wells.
Sodium sulfate natural brines are pumped from wells, settled to
remove suspended muds and then saturated with salt (NaCl). The
brine mixtures are cooled to precipitate sodium sulfate. The
precipitated solids are recovered by filtration and the spent
brine is fed to an evaporation pond as a waste. The recovered
solids are melted, calcined to effect dehydration, cooled and
packaged. A process flowsheet is shown in Figure 32.
151
-------
STEAM VENT
SODIUM
SU1 FATE
E^iNE
WELL
SETTLING
(
!
I '
COOLING
AND
SETTLING
•»»•<>
RLTR4TICN
—CR
DEHYDRATION
r+rtmt*£Sr>
DRYING
.. B» PRODUCT
(ANHYDROUS)
i
LIQUOR
SALT
CAVERN
TO
EVAPORATION
FC.ND
FIGURE 32
SODIUM SULFATE FROM BRINE WELLS
-------
POCK SALT (SIC 1176)
There are approximately 21 producers of rock salt in the United
States. Eleven facilities were visited representing over
90 percent of the salt production. The operations and the type
of waste generated are similar for the entire industry. The
sources of waste and the methods of disposition vary from
facility to facility. This study covers those establishments
engaged in mining, crushing and screening rock salt.
The salt is mined from a salt dome or horizontal beds at various
depths by conventional room and pillar methods. The face of the
material is undercut, drilled and blasted and the broken salt
passed through a multiple stage crushing and screening circuit.
The products normally 1" and smaller are hoisted to the surface
for further screening and sizing and preparation for shipment.
The extent of the final crushing and screening carried out on the
surface varies and in some cases practically all is done
underground. See Figure 33 for a typical process flow diagram.
The waste water from these salt facilities consists primarily of
a salt solution of varying sodium chloride content and comes from
one or more of the following sources:
(1) Wet dust collection in the screening and sizing steps,
(2) Washdown of miscellaneous spills in the operating area and
dissolving of the non-salable fines,
(3) Mine seepage.
Storage pile runoff.
In the mining and processing of rock salt, water consumption is
variable due to the miscellaneous nature of its use. Routine use
is for cooling, boilers (heating) and sanitation with a small
volume consumed in the process for dissolving anti-caking
reagents. Variable volumes are used in dust collection and
washdown of waste salt including non-salable fines from the
operating areas.
153
-------
PRODUCT
POCK SALT
LEGEND:
UNDERCUTTING,
CRSLLIN3
A?.D
BLASTING
MULTIPLE
STAGE
CRUSHING
A?\=D
SCREENING
ALTERNATE OR
CPT.CbAL PROCESS
1
1
1
ui
1
CRUSHING
/•- *:r>
SCREENING
PRODUCT
PREPARATION
AND
PACKAGING
---SS-PRODUCT
UNDERGROUND
SURFACE
FIGURE
33
ROCK SALT MiNIKG AND PROCESSi.NG
-------
PHOSPHATE ROCK (SIC 1U75)
Phosphate ore mining and processing is carried out in four
different regions of the United States. These areas and their
contribution to the total output are Florida, 78%; Western
states, 12%; North Carolina, 5%; and Tennessee, 5%. Eighteen to
twenty different companies with about 25 to 30 operations account
for greater than 95 percent of the output. Data collected
through visits to most of the operating facilities are analyzed
in this section.
Eighty-three percent of the ore is processed by flotation. The
major wastes associated with phosphate production are the slimes
and flotation tailings which consist primarily of clays and
sands. These are separated from the phosphate rock through
various processing techniques such as grinding, screening,
crushing, classification, and finally, desliming or a combination
of desliming and flotation. The method of processing does merit
subcategorization in that economics can preclude the extensive
use of recycled water in flotation processing.
FLOTATION
The flotation operations include all in Florida and North
Carolina and one in Utah. The ore which lies at varying depths
from the surface is mined from open pits by use of draglines and
dumped into pits adjacent to the mining cut. The material is
slurried with the use of high pressure streams of water from
hydraulically operated guns and pumped to the beneficiation
facility where it enters the washer section. This section
separates the pebble phosphate rock from the slurry which is
accomplished by a series of screening, scrubbing and washing
operations. The coarse fraction termed pebble is transferred to
product storage and the fine phosphatic material is collected and
pumped to surge bins for further processing.
The next step in the process is the removal by cyclones of the
-150 mesh fraction referred to as slimes, colloidal clays and
very fine sands, which are pumped to settling ponds. The
oversize material is transferred to the flotation section, where
it is conditioned for the first stage flotation. The floated
material may be stored "as is" or de-oiled, conditioned and
directed to a second stage flotation. The phosphate rock product
is dried and stored. The tailings (sands) from the flotation
steps are discharged as a slurry to mined out areas for land
reclamation.
Facility 1022 is the only Western facility that includes a
flotation step. After the cycloning or desliming step, the
material is fed to a flotation circuit consisting of conditioning
with rougher and cleaner cells. The flotation tailings are
155
-------
combined with slimes and thickened prior to being discharged to
the settling pond.
Facility 4003 differs in processing from the general description
in the first part of the mill operation. The ore feed slurry is
passed through a multiple stage screening step separating the
-14 mesh for flotation and the oversize is discarded. The mine
operation is unigue in that the ore lies some 30 m (100 ft) below
the surface. To maintain a dry pit, it is necessary to
de-pressurize an underlying high yield artesian aquifer. This is
accomplished through use of a series of deep well pumps
surrounding the pit that removes sufficient water to offset the
incoming flow refilling the zone. See Figure 34 for the process
flow diagram of flotation operations.
Almost all water used in the beneficiation of phosphate ore is
for processing purposes. Only minimal volumes are used for
non-contact cooling and sanitary purposes. A typical usage is in
the range of 41,000 1/kkg (10,000 gal/ton) of product with a
considerable variation occurring within the various facilities.
The wide range of water usage may be attributed to the operating
procedures and practices, the weight recovery (product/ton of
ore), the percent of ore feed processed through flotation, the
ore characteristics, and the facility layout and equipment
design.
A comparison of water usage in the various facilities is as
follows:
Facility 10* I/day
4002
4003
4004a
4004b
400 5a
400 5b
4005c
4007
4015
4016
4017
4018
4019a
401 9b
4019c
4020a
4020b
4022
248.1
411.4
205.9
121.9
246.5
107.7
370.9
none
313.0
182.1
726.4
358.2
355.0
573.8
255.9
257.4
174.1
mgd
65.5
108.7
54.4
32.2
65.0
28.5
98
82.7
48.1
191.9
94.6
93.8
151.6
67.6
68
46
1/kkg gal/ton Percent
Recycle
25,800 6200 85
45,300 10,900 60
Not Available 74
Not Available 74
18,100 4300 95
14,200 3400 95
30,600 7300 95
none (mine only) N/A
45,500 10,900 90
31,800 7600 84
91,400 21,900 90
66,600 15,900 N/A
64,300 15,400 N/A
78,000 18,700 N/A
81,100 19,400 N/A
21,300 5,100 80
32,200 7,700 85
11,200 2,700 66
156
-------
FIGURE 34
RECYCLE
\WT6R WATER
1 i
SLIMES
R2/.3VAL
I
T**
1
CONDITIONER, CC'iCH
FLCTAT'ON -|-W DE-OIL — !> PLOT
PROCESSING
EASTERN
•PRODUCT
—^•PRODUCT
SLIMES AND TAILINGS TO SETTLING POND
PHOSPHATE MINING AND PROCESSING
WESTERN
157
-------
The sources of the process water consist primarily of recycle
(from ponds) with additional makeup coming from wells and natural
streams. Generally no additional treatment of the water is
carried out prior to reuse.
The wastes associated with the various facilities and their
quantities follow:
kg/kkg (lb/1000 Ibl of product
Mine Pit Dust Scrubber
Facility Slimes
Tailings
4002
4003
4004a
4004b
4005a
400 5b
4007
4005c
4015
4016
4017
4018
4019a
401 9b
4019c
4020a
4020b
4022
790 1380
370 840
information not available
information not available
1180 900
1160 1290
no (a mine only)
1050 1520
1000 1000
1300 1300
860 2440
770
900
1290
1030
1330
1710
2140
2610
2100
1230
1570
Seepage
yes
yes
yes
yes
yes
yes
runoff only
yes
yes
yes
yes
yes
yes
yes
yes
yes
no
Slurry
no
yes
yes
no
yes
no
no
yes
yes
yes
yes
yes
yes
yes
yes
yes
no
In addition to the slimes and tailings, facility 4003 disposes of
about 120 kg/kkg product as solid waste from the initial stage of
beneficiation.
WASHING
Facilities 4006, 4008 and 4025, located in Tennessee do not
include the flotation step. The processing is complete after the
washing and desliming stages and, in some cases, after a final
filtering of the product. The locations of the mines are usually
some distance from the beneficiation facility and the ore is
brought in dry, as mined, by truck or rail.
The Western producers of phosphate rock contribute about
12 percent of the total U.S. production. All of the major
operations in this geographical area were visited. They
represent four companies and five different operating areas. The
higher net evaporation rate is the major factor responsible for
making it feasible to attain no discharge. Only one Western
plant utilizes a flotation process.
158
-------
The western bedded and inclined ore deposits lie at varying
depths and are mined by open pit methods. The mining methods
generally involve the use of scrapers, rippers and/or drilling
and blasting. The ore is transported to the facility area by
truck or rail where it enters the first stage of beneficiation
which consists of crushing and/or scrubbing. Subseguent sizing
is accomplished through further crushing, grinding and
classification, with the sized feed being directed to the
desliming section for removal of the minus 325 material. These
slimes are discharged either directly to a tailings pond or
through a thickener. The underflow product from the desliming
step is filtered. The filtered material may be further processed
through a drying and/or calcining step prior to shipment. See
Figure 34 for the process flow diagram. Facilities 4024 and 1030
do not beneficiate. The ore is mined and shipped to other
locations for processing.
At all operations where ore beneficiation occurs, the process
water recycle is 65 percent or greater. Most of the remaining
percentage of water is tied into the settled slimes. The
overflow from the settling pond is returned to the process. The
water usage is almost totally for processing (>95 percent) with
only a minimal volume used in other areas of the facility such as
non-contact cooling and sanitary. A comparison of water usage in
each facility is as follows:
1/kkg Makeup
(gal/ton) Percent water
Facility Product Recycle Source
4006 20,400 0
(4,900)
4008 18,400 66
(4,400)
4025 25,500 80
(6,100)
4023 3,500 60 wells
(830)
4029 5,000 66 wells
(1,200)
4031 8,300 75 wells
(2,000)
159
-------
The raw wastes are the slimes from desliming cones. In the
mining area of all facilities the only waste water occurring is
normal surface runoff.
Facility Slimes kg/kkg (lb/1000 Ibi of Product
4006 1000
4008 580
4025 1010
4023 500
U029 U84
4031 580
The disposition of the wastes from these facilities is to
settling ponds. In the operations that have dryers and
calciners, the dust from the scrubber system is discharged to the
slimes waste stream.
160
-------
SULFUR (FRASCH) (SIC 1477)
There are currently thirteen known significant U.S. Frasch sulfur
facilities producing molten sulfur. Two of these facilities are
located in anhydrite deposits and eleven on salt domes. Two of
the salt-dome facilities are offshore operations. Only one of
the offshore facilities is in production. The second facility
will resume operation in 1975. All of these facilities are
designed for a maximum hot water generation capacity. The
sulfur-to-water ratio varies greatly from formation to formation,
from location to location, and from time to time. The latter
occurs because normally as a mine ages, the water to sulphur
ratio increases. Therefore, the quantity of water used in this
industry category is not determined solely by the quantity of
product. More than 85 percent of the sulfur delivered to
domestic markets remains as a liquid, from well to customer.
Liquid shipments are made in heated ships, barges, tank cars and
trucks. Molten sulfur is solidified in vats prior to shipment in
dry form.
ANHYDRITE OPERATIONS
A Frasch installation starts with a borehole drilled by a
conventional rotary rig to the top of cap rock. A steel casing
is then lowered into the borehole. Drilling is then continued
into the sulfur formation. A liner, which has two sets of
perforations, is set from the surface into the sulfur formation.
The first set of perforations is several feet from the bottom and
the second set is about five feet above the first set. A second
pipe, of smaller diameter, is placed inside the liner with the
lower end open and a few inches above the bottom. A ring-shaped
seal is placed around the smaller pipe between the two sets of
perforations to close off the circulation in the annular space of
the two concentric pipes.
Incoming water is treated either by hot lime or the cold
clarification process plus softening, and a portion goes to the
boilers. steam from the boilers is used to superheat the
remaining water. Superheated water, under pressure and at a
temperature of about 163°C (325°F), is pumped down the annular
space between the two pipes, and, during the initial heating
period, dcwn through the sulfur pipe. The hot water flows
through the holes at the bottom into the sulfur-bearing deposit.
As the temperature rises, the sulfur melts. Because the liquid
sulfur is heavier than the water, it sinks to the bottom where it
enters the lower liner perforations. Pumping water down the
sulfur pipe is then discontinued. Following the direction of
least pressure, the liquid sulfur moves up through the small
pipe. Its upward motion is aided by the introduction of
compressed air through a one-inch pipe. After reaching the
surface, the liquid sulfur is collected and pumped into steam-
161
-------
heated tanks or barges for direct shipment to the customer or it
is transported to a shipping center.
In the start up of new and existing wells some hot water will
preceed the upcoming sulfur and this water will be bled, in the
case of estuary operations directly to surface waters. This is
called sealing water. In addition to producing wells,
"bleed-off" wells must be drilled in appropriate locations to
control dome pressure and permit continuous introduction of hot
water.
At facilities located in anhydrite deposits, the "bleed-off"
water is heated and reused in the system. In general, 50 percent
of the process water used in these facilities is recovered. The
remainder is lost in the sulfur-bearing formation. At facilities
located on salt domes, the "bleed-off" water is saline because of
the association of the sulfur deposits with salt domes. The
bleedwater is the major waste water of these facilities, since
the water is too corrosive to reuse.
Removal of large quantities of sulfur from the formation
increases the voids and cavities underground. Subsidence and
resulting compaction eliminate most of these void spaces.
Drilling muds are also used to fill some of the areas already
mined. Some of these facilities mix the sludge generated from
their water softening and treating operation with clay and use it
as a substitute drilling mud. Generalized process diagrams for
mines located in an anhydrite deposit and in salt domes are given
in Figure 35.
The process raw waste consists of the sludge (primarily CaC03)
which originates from the water purification operation. The raw
waste loads are presented as follows:
Waste Material kg/kkg of product fib/1000 Ib)
,at Facility 2020 2095
Water softener 9.6 15.3
sludge
Facility 2020 consumes water at an average of 6,970 1/kkg
(1,670 gal/ton) of product, 50 percent of which is recycled back
to the system and the remainder is lost in the sulfur-bearing
formation. This includes about 5 liters of non-contact cooling
water per kkg (1.3 gal/ton) of product used in their compressor
circuit. Facility 2095 uses on the average 8,470 1/kkg
(2,030 gal/ton) of product. It recovers 10-60 percent of this
water from its bleedwells.
162
-------
TREATMENT
CHEMICALS
SEA WATER
I
o\
u>
i
WATER
0^a'1*' • Tr>r/>i"n]uo _ —^ iwi roc ^ LJ~..
^!CK PLANT
i *
i i
t ' n
" i *
SLOWDOWN SLOWDOWN
1
1
LEGEWD:
*'
HEAT
EXCHANGERS
1
f
SLOWDOWN
""
SULFUR
1 *' UhPOSII
i t
i * '
i
HEATER '
1
i
i
MOLTEN
• SULFUR
PRODUCT
ANHYDRITE DEPOSITS
CONVENTIONAL SALT DOME OPERATION
PROPRIETARY SALT DOME OPERATION
BLEED WATER
TO TREATMENT
AND DISPOSAL
FIGURE 35
SULFUR MINING A&D PROCESSING
(FRASCH PROCESS)
-------
SALT DOME OPERATIONS
The process is the same as that described in Anhydrite
Operations. Raw wastes from these operations come from five
sources:
(a) bleed water,
(b) sludge from water treating and softening operations,
(c) surface runoff,
(d) mining water used in sealing wells, and
(e) miscellaneous sanitary waste, power facility area waste,
cooling water, boiler blowdown, steam traps, and drips and
drains.
The bleedwater from the mines is saline and contains dissolved
solids which have a high content of sulfides. Its guantity and
chemical composition is independent of the sulfur production
rate.
Data on bleedwater follows:
Plant
2021
2022
2023
2024
2025
2026
2027
2028
liters/day
JMGDl
74,000,000
(19.5) (1)
18,000.000
(4.7)
428,000,000
(113.0) (2)
19,000,000
(5.0)
38,000,000
(10.0)
17,000,000
(4.5)
23,000,000
(6.0)
11,500,000
(3.0)
TSS
mg/liter
<5
<5
<5
<5
39
sulfide
mg/liter
600 -
1,000
600 -
1,000
600 -
1,000
600 -
1,000
84
1,050
chloride
mg/liter
38,500
31,500
59,200
14,600
25,400
23,000
(1) Includes 69,400,000 liters per day (18.3 MGD) of seawater
used in final dilution and treatment step.
(2) Includes power plant discharge, sludge from hot lime water
softening process, miscellaneous drips and drains and
401,000,000 liters per day (106 MGD) of seawater used in
final dilution and treatment step.
The sludge from the water treating operations varies in chemical
composition and quantity depending on the type of water used in
164
-------
the process. In some facilities, only drinking water and a small
part of process water is softened and sea water constitutes the
remainder of the process water. In other facilities, fresh water
is used as process water and a portion of the facility water is
softened by hot lime process prior to usage.
Information on runoff was obtained from four facilities. The
runoff values given below are based on a one-inch rain and
100 percent runoff. The average yearly rainfall for these areas
is estimated to be 54 inches. Information on sealing well water
was available for facilities 2021 and 2024. In some facilities
this waste is separate from their tleedwater waste stream and in
others separate from the facilities miscellaneous wastes.
Facility 2021 2024
Flow, I/day (gal/day) 5,700 (1,500) 18,900 (5,000)
pH 7.9 7.5
TSS, mg/1 62 20
Sulfide, mg/1 7.8 57.2
BOD, mg/1 3.3 8.1
COD, mg/1 219 42
The waste stream for facility 2021 includes miscellaneous treated
sanitary waste, drips and drains.
165
-------
MINEEAL PIGMENTS (IRON OXIDES) (SIC 1479)
The category "mineral pigments" might be more directly classified
as "iron oxide pigments" as they are the only natural pigment
mining and processing operations found. The quantity of natural
iron oxide pigments sold by processors in the United States in
1972 was just under 63,500 kkg (70,000 tons).
One minor and two larger processors of natural iron oxide
pigments were contacted. These three companies account for
approximately 20 percent of the total U.S. production.
Iron oxide pigments are mined in open pits using power shovels or
other earth removing equipment. At some locations these
materials are a minor by-product of iron ore mined primarily for
the production of iron and steel. Some overburden may be removed
in mining.
Two processes are used, depending on the source and purity of the
ore. For relatively pure ores, processing consists simply of
crushing and grinding followed by air classification. A drying
step can be included (facility 3019). Facility 3022 and facility
3100 are dry operations. Alternatively, for the less pure ores,
a washing step designed to remove sand and gravel, followed by
dewatering and drying is used (facility 3022). Solid wastes and
waste waters may be generated in this latter process. These
processes are shown in Figure 36.
In the wet processing of iron oxide for pigment, approximately
27,800 1/kkg product of water (6670 gallons/ton) is used
(facility 3022). This process water is obtained from a large
settling pond with no additional treatment. Approximately
95 percent of this water (26,400 1/kkg of product or
6,330 gal/ton) overflows from the rake thickener, and drains to
the settling pond, while the remaining 5 percent (1,400 1/kkg or
about 340 gal/ton) is evaporated on the drum dryer.
166
-------
OVEFS
MINE
CRUSHER
ROTARY
DRYER
f
1 ROLLER
MILL
AIR
CLASSIFICATION
STEAM
•PRODUCT
fc«*5i
S
V\
LOG
WASHER
1 1
OLID
ASTE
RECYCLE
RAKE
THICKENER
i
POND
«
-------
LITHIUM MINERALS (SIC 1479)
There are two producers of lithium minerals, excluding brine
operations, and both sources are from spodumene ore which is
separated from pegmatite ores by flotation. The method of
concentrating the spodumene and the handling of the waste
generated are very similar for both facilities.
The spodumene ore is produced from an open pit using conventional
methods of mining. The ore is sized for flotation by passing
through a multiple stage crushing system and then to a wet
grinding mill in closed circuit with a classification unit. The
excess fines in the ground ore, the major waste component, are
separated through the use of cyclones and discharged to a
settling pond. The coarse fraction is conditioned through the
addition of various reagents and pumped to the flotation circuit
where the spodumene concentrate is produced. This primary
product, dependent upon the end use, is either filtered or dried.
The tailings from the spodumene flotation circuit which consists
primarily of feldspar, mica and guartz are either discharged to
the slimes-tailings pond or further processed into salable
secondary products and/or solid waste. The secondary processing
consists of flotation, classification and desliming. The waste
generated in this phase of the operation is handled similarly to
those in the earlier steps of the process. A generalized diagram
for the mining and processing of spodumene is given in Figure 37.
Reagents used in these facilities are: fatty acids; amines;
hydrofluoric acid; sulfuric acid; and sodium hydroxide and other
anionic collectors. The flocculants used for waste settling are
alum and anionic-cationic polymers.
The two waste streams common to both facilities are the
slimes-tailings from the flotation process and the mine pumpout.
The volume of waste from the process being discharged as a slurry
to the settling pond or stored as dry solids is directly related
to the guantity of secondary products recovered. An additional
waste stream which is unique to facility 4009 arises from the
scrubbing circuit of the low iron process which removes certain
impurities from a portion of the spodumene concentrate product.
Information on the wastes from each facility is as follows:
168
-------
SPCD'JMENE
ORE {OPEN
PIT MINING)
CRUSHING'
AND
GRINDING
SLIMES
REMOVAL
LEGEND:
ALTERNATE OR
OPTIONAL PROCESS
-«s
SPODUMENE
FLOTATION
BY-PRODUCT
FLOTATION
AND
CLASSIFICATION
SLIMES-TAILINGS TO SETTLING POND
(OVERFLOW RECYCLED TO PROCESS )
WASTE
FILTER
T
I
±
SPODUMENE
CONCENTRATE
PRODUCT
DRYER
MAGNETIC
SEPARATION
i
t
LOW IRON
PROCESSING
SPODUMENE
-CONCENTRATE
PRODUCT
• BY-PRODUCT
CERAMIC
SPCDUMENE
PRODUCT
LOW IRON
*SPODU:/EN
PRODUCT
SPODUMENE
(
FIGURE
MINING
AMD PROCESSING
PROCESS)
-------
Facility 4001
Waste Material
Slimes
Tailings
Mine water
Facility 1009
Waste Material
Slimes & tailings
Mine water
Scrubber slurry
Source
flotation
dewatering
mine pit
Source
flotation
mine pit
Low iron
process
kcr/kkg of feed
(Ibs/lOOO Ib)
100
unknown
(intermittent, unknown)
kg/kkg of feed
(lbs/1000 Ib)
620
568,000 I/day
(0.15 mgd) est.
95,000 I/day
(0.025 mgd) est.
At both facilities the process water recycle is 90 percent or
greater. With the exception of the above mentioned scrubber
slurry, the process waters are discharged to a settling pond
where a major part of the overflow is returned for re-use. A
breakdown of water use at each facility follows.
Facility UP01
1. Water Usage
Process
Non-contact
cooling
Total
1/kkg
of ore
{gal/ton)
12,500 (3,000)
250 ( 60)
12,750 (3,060)
Water
Source Recycle
a) Settling 95
pond overflow
b) Mine pumpout
c) Well
Well 100
2. Water Recycled 12,100 (2,900)
170
-------
Facility 4009
1. Water Usage
Process
Non-contact
cooling
Boiler
Sanitary
Total
1/kkg
of ore
(gal/ton)
26,900 (6,450)
1) 380 (90)
2) 270 (60)
40 (10)
190 (50)
27,780 (6,660)
Water
Source
Recycle
a) Settling 90
pond overflow
b) Creek
a) Settling 90
pond overflow
b) Creek
Municipal 0
Municipal
2. Water Recycled 24,600 (5,900)
171
-------
EENTONITE (SIC 1452)
Bentonite is mined in dry, open pit quarries. After the
overburden is stripped off, the fcentonite 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 38.
There is no water used in the mining or processing of bentonite.
Solid waste is generated in the mining of bentonite in the form
of overburden, which must be removed to reach the bentonite
deposit. Solid waste is also generated in the processing of
bentonite as dust from drying, crushing, and other facility
operations.
172
-------
CO
CRUSHER
„_. , , ., VFNT
! i t
I
OPEN PIT !
QUARRY ""*"'cu
DRYER
1
i
SCREENS
ID 1701 1 Mil 1 to STORAGE
88 ROLL M|LL •* BINS
4 A
i 1
i i
i i
i
_j
PRODUCT
FIGURE 38
BENTONITE MINING AND PROCESSING
-------
FIRE CLAY (SIC 1453)
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. Fire clay is obtained from open
pits using bulldozers and front-end loaders. 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 3017) 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 39.
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 the frequency of rainfall and the
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 into the
clay pits. No process water is used. The solid waste generated
in fire clay mining is overburden which is used as fill to
eventually reclaim mined-out areas.
-------
OPEN
PIT
T
CRUSH
H
SCREEN
REFRACTORY
OPERATIONS
•^PRODUCT
CALCINE
PRODUCT
l_
PRODUCT
FIGURE 39
FIRE CLAY MINING AND PROCESSING
-------
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.
ATTAPULGITE
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 40.
No water is used in the mining, but rain and ground water do
collect in the pits, particularly during the rainy season.
Untreated creek water serves as make-up for facilities 3058 and
3060. Water is used by facility 3058 for cooling, pug milling,
and during periodic overload for waste fines slurrying. 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. Typical flows are:
1/kkq of product
(gal/ton)
3058 3060
Intake:
Make-up ft60 (110) unknown
Use:
cooling 184 (44) unknown
waste disposal 230 (55) 345-515
and dust collection (82-122)
pug mill 46 (11) 42 (10)
Discharge:
cooling water none unknown
process discharge none none
evaporation 230 (55) 42 (10)
176
-------
FIGURE 40
OPEN
PITS
warra—
CRUSHING
SCREENING
i
PUS _
MILL
HA.cR »
VENT
SCRUBBERS
i
,-, ROTARY
DRYERS
A
1
1
1
1
1
MILLS
POND
NOTE
SCREENS
R — *"•!
r
PONQ
i
EFFLUENT
EFFLUENT
> ALTERNATE PTOCESS W3UTES
•/
J
TJ
FULLER'S EARTH MINING AND PROCESSING
(ATTAPULGITE)
• PRODUCT
PRODUCT
PIT
CRUSHING
DRYER AND COOLER
LEGEND:
ALTERNATE AIR
POLLUTION TREATMENTS
CLAY SU'OGE
TO MINE
> PRODUCT
DUST AND FINES TO MINE
FULLER'S EARTH MINING AND PROCESSING
(MONTMORILLONITE)
177
-------
MONTMORILLONITE
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 40.
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 of water, except in
the case of facility 3073 which uses this water as scrubber water
makeup. The estimated flow is up to 1110 I/day (300 gpd).
Water is used in processing only in dust scrubbers. Typical
flows are:
1/kkq product (gal/ton)
Facility 3059 3072 3073 3323
Dust Scrubbers 1,930 («»60) 500 (120) 1U3 (34) 3,650 (876)
Discharge none 150 (36) none
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.
178
-------
KAOLIN (SIC 1455)
DRY PROCESS
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 into refractory
products. Processing at facility 3036 consists of grinding,
drying, classification and storage. A general dry process
diagram is given in Figure 41. 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. There is no waste generated in the mining of
the kaolin other than overburden, and in the processing, solid
waste is generated from classification.
WET PROCESS
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 prior to pumping
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
(70% solids) in tank cars. A general wet process diagram is
given in Figure 41.
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 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:
1/kkg product (gal/ton)
3024 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)
179
-------
FIGURE 41
TRUCK
DRYING
AND
CLASSIFICATION
• PRODUCT TO SHIPPING
— -^TO ON-SITE REFRACTORY
MANUFACTURING
SOLID
WASTE
EFFLUENT
DRY KAOLIN MINING AND PROCESSING
FOR GENERAL PURPOSE USE
WATER
ZINC
HYDROSULFITE
OEOR{TT,NO _^ «£*$
CLASSIFICATION | TCRf$=
WATERBORNE
TAILINGS TO
SETTLING PCND
OR BY-PROOUCT
RECOVERY
ING
'R _ . -n PIITR
AL T^ FILTR
ENT I
LIME 1»
1
ATION
POND
EFFLUENT
1
KAOLIN
i
BULK
SLURRY
•PRODUCT
70%
SLURRY
PRODUCT
WET KAOLIN MINING AND PROCESSING
FOR HIGH GRADE PRODUCT
180
-------
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 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 originates from the bleaching
operations. The raw waste loads at these two facilities are:
Waste Material
zinc
dissolved solids
suspended solids
kg/kko product (lb/1000 Ibl
3024 3025
0.37
8
35
0.5
10
100
The dissolved solids are principally sulfates and sulfites and
the suspended solids are ore fines and sand.
181
-------
BALL CLAY (SIC 1455)
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 42.
There is no water used in ball clay mining. However, when rain
and ground water collects in the mine there is an intermittent
discharge. There is usually some diking around the mine to
prevent run-off from flowing in. In ball clay processing, two of
the facilities visited use a completely dry process. The others
produce a slurry product using water for blunging and for wet
scrubbers. Well water serves as the source for the facilities
which use water in their processing. Typical flows are:
1/kkg of product (gal/ton)
5684 5685 5689
Blunging unknown 42 (10) none
Scrubber 88 (21) 1,080 4,300
(260) (1,030)
Water used in blunging operations is either consumed in the
product and or evaporated. 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.
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 rotary 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.
182
-------
HOT
AIR
PITS
SHRED
H
STOCKPILE
1 HAMMER
MILL
CYCLONES
,f
— »
BAG
HOUSE
t
PARATOR
1
1
LEGEND:
CO
OJ
> ALTERNATE PROCESS ROUTES
ROTARY
DRYER
WATER
SCRUBBERS
CHEMICALS -
WATER-
BLUN6ER
POND
SCREEN
SOLID WASTE
(LIGNITE, SAND)
EFFLUENT
BAGGED
PRODUCT
BULK
PRODUCT
to SLURRY
PRODUCT
FIGURE 42
BALL CLAY MINiNG AND PROCESSING
-------
FELDSPAR
Feldspar mining and/or processing has been sub-categorized as
follows: flotation processing and non-flotation (dry crushing and
classification). Feldspathic sands are included in the
Industrials Sands sutcategory.
FFiDSPAR - FLOTATION
This subcategory of feldspar mining and processing is charac-
terized by dry operations at the mine and wet processing in the
facility. 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.
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 done at the facility, but sometimes at the mine
(Facility 3068). Subsequent steps for all wet processing
facilities vary in detail, but the basic flow sheet, as given in
Figure 43, 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 3068). 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. 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 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.
184
-------
FIGURE 43
QUARRY
/»« KiUPpJC
BALL
MILLS
AIR
CLASSIFICATION
•PRODUCT
FELDSPAR MINING AND PROCESSING
(DRY)
WATER
WATER
FLOTATION
AGENTS
1 1
CLASSIFICATION,
CONDITIONING,
AND
FLOTATION
(3 REPETITIONS)
IRON
SOLID
WASTE
PRODUCT
PRODUCT
BY-PRODUCT
MICA FROM
-*.FRST FLOAT
WASTE
SLURRIES
TO
PONO
•BY-PRODUCT
SAND FROM
THIRD FLOAT
FELDSPAR MINING AND PROCESSING
(WET)
185
-------
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
Mining operations at the open pits result in overburden of
varying depth. The overburden is used for 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
processed fib/1000 lb>
facility ore tailings and slimes fluoride
3026 270 0.22
3054 U10 0.2U
3065 260 0.20
3067 530 est. 0.25
3069 350 est. 0.25
FELDSPAR - NON-FLOTATION
This subcategory of feldspar mining and processing is charac-
terized 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
186
-------
approximately 8.5 percent of total U.S. feldspar production.
However, there are two important elements of difference between
these two operations. 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.
Underground mining is done 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 that 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.
At the two facilities the ore processing operations are virtually
identical. They consist of crushing, ball milling, air
classification, and storage prior to shipping. Product grading
is performed by air classification. A schematic flow sheet is
shown in Figure 43.
At the mine 3032, 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 for
processing at the mine. At Facility 3064, no water is used at
the mine. 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.
At Facility 3032, there are no mine wastes generated, and only a
small quantity of high-silica solid wastes result from the
facility, and the material is used as land fill. At Facility
3064, the rejects from hand picking are used as mine fill. There
is very little waste at the facility.
187
-------
KYANITE
Kyanite is produced in the U.S. from 3 open pit minesr 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.
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 desliming,
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 4*».
Water is used in kyanite processing in flotation, classification,
and slurry transport of ore solids. This process water amounts
to:
1/kkq of kyanite (gal/ton)
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.
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.
waste material kg/kkg of kvanite (lb/1000
facility 3015 tailings 2.500
facility 3028 tailings 5,700
188
-------
00
10
WATER
WATER . RECYCLE w;
j rn
CLASS
-» COND
FLO
FLOTATION
REAGENTS
*T.ER j VENT
IFICATION, MAGNETIC
ITIONING, » DRYING — — •• grpADATiON
fATION StPARATIOIN
UNDERFLOW
TAILINGS SCA
i ' f
TO WASTE
POND
* KYANITE
'
to ROTARY fc MULLITE
KILN rnUUUv* 1
LPINGS
RGURE ^
KYANITE MINING AND PROCESSING
-------
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.
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/U
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 tc two Herreshoff furnaces. By controlling the
amount of CO2 liberated from the magnesite a caustic 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.
190
-------
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 process 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 tagged 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 HO percent
solids is impounded in the facility. A simplified flow diagram
for this facility is given in Figure 15.
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°P). 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:
191
-------
ORE
CRUSHERS
10
po
1 i
5%
FINES
TO
WASTE
15%
TO
KILN
-»»
x5C
<-30
-*»
CRUSHER
%
%
CRUSHERS
ROD MILLS
AND
CLASSIFIERS
t
„,
1 OVERFLOW
RECYCLED
WATER
I
HEAVY
MEDIA
SEPARATION
PLANT
SOLID
WASTE
FLOTATION
AGENT
i
ROUGHER
AND
CLEANER
CELLS
i RECYCLE
TAILINGS
THICKENER
VENT
t
BAG
HOUSE
T 1
DRYING,
CONCENTRATE VACUUM ^Slir6"
THICKENER h" *H F.LTERS — gjgjjj^
1 1 croccwiMn
FILTRATE
MAGNESIA
PRODUCT
MAKE-UP WATER
UNDERFLOW
40% SOLIDS
TO SETTLING POND
FIGURE 45
MAGNESITE MINING AND PROCESSING
-------
water consumption 1/dav (gal/day)
process water to refine the
product 163rOOO (43,000)
road dust control 227,000 (60,000)
sanitary 11r360 ( 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)
The raw waste from this facility consists of the underflow from
the tailings thickeners and it includes about 40 percent
suspended solids amounting to 590,000 kg/day (1,300,000 Ib/day).
193
-------
SHALE AND COMMON CLAY
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 the 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 and common
clay are mined in open pits using rippers, scrapers, bulldozers,
and front-end loaders. Blasting is needed to loosen very hard
shale deposits. The ore 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 46. Solid waste is
generated in 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.
There is no water used in shale or common clay 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.
-------
COARSE
to
in
SHALE 1 J PRIMARY
PIT (I CRUSHER
1
GRIND
SCREEN
PRODUCTS
PIT
PUMPOUT
FIGURE 46
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. 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 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. 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 100X 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. There is no mine
pumpout at facility 3016 and any surface water which accumulates
drains naturally to a nearby river.
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
47 depicting both processes. This water totals 1,230,000 I/day
(324,000 gpd) with no recycle. There is occasional mine pumpout.
1/kkq product (gal/ton)
process use; 3016 3020
scrubber or dust 3,600 (870) 5,900 (1,420)
control
crush, screen, 12,700 (3,040) 0
classify
net discharge (less approx. 0 5,900 (1,420)
mine pumpout)
mine pumpout 0 not given
make-up water not given 5,900 (1,420)
intake
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.
196
-------
LEGEND:
DRY PROCESS
WET PROCESS
WATER-
SCRUBBERS
DUST, FINES
to
t I
' 1
i i
i
SCREENING -to CYCLONE •
1
, CRUSHING . CLASSIFY
SCREENING ^^* CLASSIFY
MAGNETIC
SEPARATION
1
VENT
t
DRYING
---to CLASSIFY -— ^ AND
SCREENING
i»_J
!
1 *
IRON SANDS
TO LANDFILL
OR 8EACH SAND
I
POND
I
,L
, APLITE
PRODUCT
, AP'JTE
PRODUCT
POND
FIGURE 47
APLITE MINING AND PROCESSING
EFFLUENT
-------
kq/kkq
Waste kkq/vear product
Materials (ton/vrl (lb/1000 Ib)
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 solid wastes come from the magnetic separation step at
facility 3020.
198
-------
TALC, STEATITE, SOAPSTCNE 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. Four are wet crude
ore beneficiation facilities, three using froth flotation and one
heavy media separation techniques.
DRY GRINDING
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. The ore, containing less than
12% moisture is 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 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 U8.
There is no water used in dry grinding 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. 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. Even though these
facilities do not use water in their process, some of them do
have mine water discharge from their underground mine workings.
LOG WASHING AND WET SCREENING
At log washing facility 2031 and wet screening facility 2035,
water is used to wash fines from the crushed ore. In both
facilities, 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.
199
-------
FIGURE 48
TALC ORE-
JAW WET
AUD ___,„ «*T „
CRUSHERS BIN *
r
• HNS „_„ — '
CRUSHING _ S?L COA
PEBBLE
KILL
GR.t.-^ING
CluCUIT
«e5
fJD t>r;YING ~~"^ c0^, VATtRiAL
CIRCUIT SILOS __,
STEAM
OR
COMPRESSED
AIR
FLUID
ENERGY
GRINDING — •^'WUCTt
CIRCUIT
DRY
COLLECTOR
^PRODUCT
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE MINING AND PROCESSING
(DRY)
ORE-
W&TER-
LOS
WASHER
VIBRATING
SCREEN
SCREW
CLASSIFIER
OVERSIZE TO
STOCKPILE
AND MILLING
(FINES
KYDROCLONE
SLIMES TO
SETTLING POND
••PRODUCT
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE MINING AND PROCESSING
(LOG WASHING PROCESS)
CRUDE ORE
—tt] CRUSHEl
TAILINGS TO FOND
OUCT
SLIMES CVC'ISIIE
TO PONO TO DUMP
TALC, STEATITE, SOAPSTONE AND PYRCPHYLLITE MINING AND PROCESSING
(WET SCREENING PROCESS)
200
-------
At facility 203ft 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 2C35, 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 203ft and 2035 are given in Figure ft8.
Both facilities are supplied by water wells on their property.
Essentially all water used is process water. Facility 203ft 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).
The raw waste from facility 203ft 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.
FLOTATION AND HEAVY MEDIA SEPARATION
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 feeds a rake thickener which raises the
solids content of the flotation product from 10 to 35 percent.
The product from the 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 ft9.
201
-------
FIGURE 49
TALC ORE •
CRUSHING 1
DRYir-'G, .— * CO
1
FLOTATION
WATER | REAGCNTS
V | 7
1
1
_—- __ I
P'
DISTF
A
CONCE'
TA
T^L-__
•3UTOR DISTRIBUTOR THICKENER
TRATlrlG FL5IA,'LON FILTER
;LES CELLS
1
If < '
TAILINGS BASIN
LEGEND:
i i
"\
ALTERNATE PROCESSES
CLARIFICATION
BASINS
EFFLUENT
TALC MINING AND PROCESSING
{FLOTATION FRGCtaS)
CRUDE ORE1
•PRODUCT
LIME
TO SETTLING POND
TALC MINING AND PROCESSING
(IMPURE ORE)
202
-------
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.
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
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
49. 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 2044 consumes on the average 1/kkg
(1,305 gal/ton) total product.
Facility 2044 uses heavy media separation (HMS) technique for the
beneficiation 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 btfore further crushing and screening
operations; the plus 5.1 cm (2 in) fraction is crushed, screened
and sized. The minus 3 to plus 20 mesh material resulting from
the final screening operation is sent to the HMS unit 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 11 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 50. The hydraulic load of these
facilities is summarized as follows:
Consumption I/day (gal/day)
at Facility No. 20\31 2032 2033 2044
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)
In facilities 2031 and 2032, the raw waste consists of the mill
tailings emanating from the flotation step. In facility 2033, in
203
-------
ORE
AIR
rR g,
PRIMARY
CRUSHER
1
DRYER
1
WET
SCRUBBER
1
SETTLING
POND
CRUSHING
AND
SCREENING
.
f
PEBBLE
MILLS
AIR
CLASSIFIER
WATER
I
HEAVY
MEDIA
PLANT
r
SCREENING
AND
SCREW
CLASSIFIERS
(
CRUSHING
SCREENING
T
EFFLUENT
PYROPHYLLITE
PRODUCT
WET SAND
BY-PRODUCT
ANDALUSiTE
BY-PRODUCT
PYROPHILLITE
BY-PRODUCT
WASTE
TO SETTLING POND
FIGURE 5n
PYROPHYLLITE MINING AND PROCESSING
(HEAVY MEDIA SEPARATION)
-------
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 kg/kkq of flotation product (lb/1000 Ib)
at Facility No. 2031 2032 2033 2044
TSS 1800 1200-1750 800 26
205
-------
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. The two
garnet operations studied are in widely differing geographic
locations, and so the garnet deposits differ, one being mountain
schists (3071), and the other an alluvial deposit (3037).
Facility 3071 mines by open pit methods with standard drilling
and blasting eguipment. 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
dewatared 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 drc.gline 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 where the heavier garnet is
separated from all impurities except for 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 51 gives the general flow diagram for these operations.
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.
At facility 3071, water is collected from natural run-off and
mine drainage into surface reservoirs, and 24,600 1/kkg (5,900
gal/ton) of product is used in both the heavy media and flotation
units. This process water amounts to approximately 380-760 1/min
(100-200 gpm) of which half is recycled. Effluent flow varies
206
-------
QUARRY
WATER-
PO
o
T RECYCLE
TRUMBLE
ARC
LARGE
STONES
FOR
FILL
WATER-
JIG
SETTLING
POND
i
rLU!
WATER•
COARSEs
CRUSHING
HEAVY
MEDSA
PLANT
I A <- RECYCLE
i P
DEWATERING
SCREEN
WATER
COARSE TAILINGS
SOLD AS ROAD GRAVEL
FLOTATION
DRYING
RECYCLE
THICKENER
SETTLING
PONDS
EFFLUENT
EFFLUENT
FIGURE 51
GARNET MINING AND PROCESSING
MILLING
AND
SCREENING
h-
PRODUCT
-------
seasonally from a springtime maximum of 570 1/min (150 gpm) to a
minimum in summer and fall.
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.
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.
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 52. At one facility only a special grade tripoli (a minor
portion of the production, value approximately $250,000/year) is
made by a unigue process using wet-milling and scrubbing.
There is no watpr used in mining, nor is there any ground water
or rain water accumulation in the mines. The standard process is
a completely dry process. 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.
208
-------
ro
o
MINE
CRUSH
SCREEN
DRY
MILL
BAG
HOUSES
1
CYCLONES
I
AIR
CLASSIFY
PRODUCT
RGURE 52
TRIPOLI MINING AND PROCESSING
BY THE 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.
After the overburden is removed from the diatomite strata by
power-driven shovels, scrapers and bulldozers, the crude diato-
mite is dug from the ground and loaded onto trucks. Facilities
5501 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. These processes are diagrammed in Figure 53.
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.
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.
210
-------
LEGEND:
WATER
RECYCLE (
pnwn
POND
WATER
MINE
CRUSH
GENERAL PROCESS FLOW
> ALTERNATE PROCESS
I ROUTES
SCRUBBERS
—i—
VENT
BAG HOUSE
T DUST J
BINS
•*» PRODUCT
DRY
AIR CLASSIFY
REAGENT
ROD MILL
l_.
•1
I
i
CALCINE
CLASSIFY
•PRODUCT
•PRODUCT
WATER
CYCLONE
TRAPS
PUG MILL
I
I
WASTE TO LAND DISPOSAL
RGURE 53
DIATOMITE MINING AND PROCESSING
-------
1/kkg ore processed
(gallon/ton)
5500 5505 5501
Intake:
make-up water 2,800 880 3,800
(670) (210) (910)
Use:
dust collection 2,670 8,700 3,800
and waste disposal (640) (2,090) (910)
bearing coolinq 125-160 (30-38)
Consumption:
evaporation 2,800 880 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.
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 facility
5504 and 5-6 percent solids as a slurry from scrubber operations
at facility 5505.
waste material kq/kkg ore (lb/1000 Ib)
Facility 5500, oversize, 200
dust fines
Facility 5504, sand, rock, 175
heavy diatoms
Facility 5505, dust 45
fines (slurry)
212
-------
GRAPHITE
There is one producer of natural graphite in the United States.
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 54.
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.
water consumption 1/metrie tons of product
(gal/ton)
total intake 159,000 (38,000)
process waste discharge 107,000 (26,000)
consumed (process, non-
contact cooling, sani- 52,000 (12,000)
tation)
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) and an intermittent seepage from the
mine. The flotation reagents used in this process are alcohols
and pine oils.
213
-------
GRAPHITE ORE
LIME WATE
1 I
MAKE-UP
WATER REAGENTS WATER
GRINDING
AND
CLASSIFICATION
ro
I MINE
-• at
u
t-'-
I ------ 1
SEEPAGE
=AGE
LIME
TREAT
TAILINGS
SUMP
^-
TAII IM
TAILINGS
POND
I
PLANT EFFLUENT
FIGURE 54
GRAPHITE MINING AND PROCESSING
PRODUCT
PRODUCT
-------
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.
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 into gems and 47 percent is
processed into floor and table tiles, grave markers, and
artifacts. A general process diagram is given in Figure 55.
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. Approximately 50 percent of
the rock taken each year from the guarry is unusable or
unavoidably wasted in processing, amounting to 26.7 kkg/yr (29.5
tons/yr). There is no mine pumpout associated with this
operation.
215
-------
ro
•-•
Ol
QUARRY
w/
w
GF
'ATER SiC
1 i
WIRE
SAW
WATER
AND
POLISHING
OIL WATER SiC AGENTS
U II L.
tf^ RECYCLE
DIAMOND
SAW
1 |
r
SETTLING
TANK
1
SETTLING
TANK
1 J 1
ATER TAILINGS TAILINGS
TO TO TO
JOt'ND LANDFILL LANDFILL
* * r
i i
^RE
AG
PO
PRODUCT
RECYCLE POLISHING
AGENTS TO EXTENT
FIGURE 55
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. Processing
consists 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 of 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 jdiaqram is given in Figure 56.
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 7,300-14,500 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.
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. However, a new facility dust scrubber will be installed
with recycle of both water and fines.
217
-------
VENT
DRY
MIX
SPECIALTY
PRODUCTS
t
oo
QUARRY
poi icucp
unuoncn
rtRYFR
ur\ i en
' AIR
CLASSIFY
PEBBLE
MILL
RGURE 56
NOVACULITE MINING AND PROCESSING
-------
SECTION VI
SELECTION OF POLLUTANT PARAMETERS
Total suspended solids, dissolved solids, sulfide, iron, zinc,
fluoride and pH were found to be the major waste water pollutant
parameters. The rationale for inclusion of these parameters are
discussed as follows.
DISSOLVED SOLIDS
Total dissolved solids are a gross measure of the amount of
soluble pollutants in the waste water. It is an important
parameter in drinking water supplies and water used for
irrigation. Dissolved solids are found in significant quantities
in rock salt, brine and trona operations. In natural waters the
dissolved solids consist mainly of carbonates, chlorides,
sulfates, phosphates, and possibly nitrates of calcium,
magnesium, sodium and potassium, with traces of iron, manganese
and other substances.
Some communities in the United States and in other countries use
water supplies containing 2,000 to 1,000 mg/liter of dissolved
salts, when no better water is available. Such waters are not
palatable, may not quench thirst, and may have a laxative action
on new users. Waters containing more than 1,000 mg/liter of
total salts are generally considered unfit for human use,
although in hot climates such higher salt concentrations can be
tolerated whereas they could not be in temperate climates.
Waters containing 5,000 mg/liter or more are reported to be
bitter and act as bladder and intestinal irritants. It is
generally agreed that the salt concentration of good, palatable
water should not exceed 500 mg/liter.
Limiting concentrations of dissolved solids for fresh-water fish
may range from 5,000 to 10,000 mg/liter, according to species and
prior acclimatization. Some fish are adapted to living in more
saline waters, and a few species of fresh-water forms have been
found in natural waters with a salt concentration of 15,000 to
20,000 mg/liter. Fish can slowly become acclimatized to higher
salinities, but fish in waters of low salinity cannot survive
sudden exposure to high salinities, such as those resulting from
discharges of oil-well brines. Dissolved solids may influence
the toxicity of heavy metals and organic compounds to fish and
other aquatic life, primarily because of the antagonistic effect
of hardness on metals. Water with total dissolved solids over
500 mg/liter water has little or no value for irrigation.
Dissolved solids in industrial waters can cause foaming in
boilers and cause interference with cleanness, color, or taste of
219
-------
many finished products. High concentrations of dissolved solids
also tend to accelerate corrosion.
Dissolved solids are only regulated in cases where no discharge
of pollutants is specified. This is usually by means of solar
evaporation, total recycle or covered storage facilities.
Reduction of TDS by other means such as ion exchange is judged to
be economically infeasible.
FLUORIDE
Fluorine is the most reactive of the nonmetals and is never found
free in nature. It is a constituent of fluorite or fluorspar,
calcium fluoride, cryolite, and sodium aluminum fluoride. Due to
their origins, fluorides in high concentrations are not a common
constituent of natural surface waters; however, they may occur in
hazardous concentrations in ground waters.
Fluoride can be found in plating rinses and in glass etching
rinse waters. Fluorides are also used as a flux in the
manufacture of steel, for preserving wood and mucilages, as a
disinfectant and in insecticides.
Fluorides in sufficient quantities are toxic to humans with doses
of 250 to U50 mg giving severe symptoms and 1.0 grams causing
death. A concentration of 0.5 g/kg of body weight has been
reported as a fatal dosage.
There are numerous articles describing the effects of fluoride-
bearing waters on dental enamel cf 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 4 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. The recommended maximum levels of
fluoride in public water supply sources range from 1.4 to 2.U
mg/1.
Fluorides may be harmful in certain industries, particularly
those involved in the production of food, beverages,
pharmaceutical, and medicines. Fluorides found in irrigation
waters in high concentrations (up to 360 mg/1) have caused damage
to certain plants exposed to these waters. 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
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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 the industrial sand, fluorspar and feldspar
subcategories.
PH
Although not a specific pollutant, pH is related to the acidity
or alkalinity of a waste water stream. It is not a linear or
direct measure of either, however, it may properly be used as a
surrogate to control both excess acidity and excess alkalinity in
water. The term pH is used to describe the hydrogen ion
hydroxyl ion balance in water. Technically, pH is the hydrogen
ion concentration or activity present in a given solution. pH
numbers are the negative logarithim of the hydrogen ion
concentration. A pH of 7 generally indicates neutrality or a
balance between free hydrogen and free hydroxyl ions. Solutions
with a pH above 7 indicate that the solution is alkaline, while a
pH below 7 indicate that the solution is acid.
Knowledge of the pH of water or waste water is useful in
determining necessary measures for corrosion control, pollution
control, and disinfection. Waters with a pH below 6.0 are
corrosive to water works structures, distribution lines, and
household plumbing fixtures and such corrosion can add
constituents to drinking water such as iron, copper, zinc,
cadmium, and lead. Low pH waters not only tend to dissolve
metals from structures and fixtures but also tend to redissolve
or leach metals from sludges and bottom sediments. The hydrogen
ion concentration can affect the "taste" of the water and at a
low pH, water tastes "sour".
Extremes of pH or rapid pH changes can exert stress conditions or
kill aquatic life outright. Even moderate changes from
"acceptable" criteria limits of pH are deleterious to some
species. The relative toxicity to aguatic life of many materials
is increased by changes in the water pH. For example,
metalocyanide complexes can increase a thousand-fold in toxicity
with a drop of 1.5 pH units. Similarly, the toxicity of ammonia
is a function of pH. The bactericidal effect of chlorine in most
cases is less as the pH increases, and it is economically
advantageous to keep the pH close to 7.
TOTAL SUSPENDED SOLIDS
Suspended solids include both organic and inorganic materials.
The inorganic compounds include sand, silt, and clay. The
organic fraction includes such materials as grease, oil, tar, and
animal and vegetable waste products. These solids may settle out
rapidly and bottom deposits are often a mixture of both organic
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and inorganic solids. Solids may be suspended in water for a
time, and then settle to the bed of the stream or lake. These
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 plants.
Suspended solids in water interfere with many industrial
processes, cause foaming in boilers and incrustations on
equipment exposed to such water, especially as the temperature
rises. They are undesirable in process water used in the
manufacture of steel, in the textile industry, in laundries, in
dyeing and in cooling systems.
Solids in suspension are aesthetically displeasing. When they
settle to form sludge deposits on the stream or lake bed, they
are often damaging to the life in water. 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 nature,
solids use a portion or all of the dissolved oxygen available in
the area. Organic materials also serve as a food source for
sludgeworms and associated organisms.
Disregarding any toxic effect attributable to substances leached
out by water, suspended solids may kill fish and shellfish by
causing abrasive injuries and by clogging the gills and
respiratory passages of various aquatic fauna. Indirectly,
suspended solids are inimical to aquatic life because they screen
out light, and they promote and maintain the development of
noxious conditions through oxygen depletion. This results in the
killing of fish and fish food organisms. Suspended solids also
reduce the recreational value of the water.
Total suspended solids are the single most important pollutant
parameter found in the mineral mining and processing industry.
TURBIDITY
Turbidity of water is related to the amount of suspended and
colloidal matter contained in the water. It affects the
clearness and penetration of light. The degree of turbidity is
only an expression of one effect of suspended solids upon the
character of the water. Turbidity can reduce the effecteveness
of chlorination and can result in difficulties in meeting BOD and
suspended solids limitations. Turbidity is an indirect measure
of suspended solids.
SULFIDES
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Sulfides may be present in significant amounts in the wastewater
from the manufacture of rock salt and sulfur facilities.
Concentrations in the range of 1.0 to 25.0 mg/1 of sulfides may
be lethal in 1 to 3 days to a variety of fresh water fish.
IRON (Fe)
Iron is an abundant metal found in the earth's crust. The most
common iron ore is hematite from which iron is obtained by
reduction with carbon. Other forms of commercial ores are
magnetite and taconite. Pure iron is not often found in
commercial use, but it is usally alloyed with other metals and
minerals, the most common being carbon.
Iron is the basic element in the production of steel and steel
alloys. Iron with carbon is used for casting of major parts of
machines and it can be machined, cast, formed, and welded.
Ferrous iron is used in paints, while powdered iron can be
sintered and used in powder metallurgy. Iron compounds are also
used to precipitate other metals and undesirable minerals from
industrial waste water streams.
Iron is chemically reactive and corrodes rapidly in the presence
of moist air and at elevated temperatures. In water and in the
presence of oxygen, the resulting products of iron corrosion may
be pollutants in water. Natural pollution occurs from the
leaching of soluble iron salts from soil and rocks and is
increased by industrial waste water from pickling baths and other
solutions containing iron salts.
Corrosion products of iron in water cause staining of porcelain
fixtures, and ferric iron combines with the tannin to produce a
dark violet color. The presence of excessive iron in water
discourages cows from drinking and, thus, reduces milk
production. High concentrations of ferric and ferrous ions in
water kill most fish introduced to the solution within a few
hours. The killing action is attributed to coatings of iron
hydroxide precipitates on the gills. Iron oxidizing bacteria are
dependent on iron in water for growth. These bacteria form
slimes that can affect the esthetic values of bodies of water and
cause stoppage of flows in pipes.
Iron is an essential nutrient and micronutrient for all forms of
growth. Drinking water standards in the U. S. have set a
recommended limit of 0.3 mg/1 of iron in domestic water supplies
based not on the physiological considerations, but rather on
aesthetic and taste considerations of iron in water.
ZINC
Occurring abundantly in rocks and ores, zinc is readily refined
into a stable pure metal and is used extensively as a metal, an
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alloy, and a plating material. In addition, zinc salts are also
used in paint pigments, dyes, and insecticides. Many of these
salts (for example, zinc chloride and zinc sulfate) are highly
soluble in water; hence, it is expected that zinc might occur in
many industrial wastes. On the other hand, some zinc salts (zinc
carbonate, zinc oxide, zinc sulfide) are insoluble in water and,
consequently, it is expected that some zinc will precipitate and
be removed readily in many natural waters.
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 the 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 may die as long as 48 hours after
the removal. The presence of copper in water may increase the
toxicity of zinc to aquatic organisms, while the presence of
calcium or hardness may decrease the relative toxicity. A
complex relationship exists between zinc concentrations,
dissolved oxygen, pH, temperature, and calcium and magnesium
concentrations. Prediction of harmful effects has been less than
reliable and controlled studies have not been extensively
documented.
Concentrations of zinc in excess of 5 mg/1 in public water supply
sources cause an undesirable taste which persists through
conventional treatment. Zinc can have an adverse effect on man
and animals at high concentrations. Observed values for the
distribution of zinc in ocean waters varies widely. The major
concern with zinc compounds in marine waters is not one of actute
lethal effects, but rather one of the long term sublethal effects
of the metallic compounds and complexes. From the point of view
of accute lethal effects, invertebrate marine animals seem to be
the most sensitive organisms tested. A variety of freshwater
plants tested manifested harmful symptoms at concentrations of 10
mg/1. Zinc sulfate has also been found to be lethal to many
plants and it could impair agricultural uses of the water.
SIGNIFICANCE AND RATIONALE FOR REJECTION OF POLLUTION PARAMETERS
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;
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(3) treatment does not "practicably" reduce the parameter; and
(U) simultaneous reduction is achieved with another parameter
which is limited.
TOXIC MATERIALS
Although arsenic, antimony, barium, boron, cadmium, chromium,
copper, cyanide ion, manganese, mercury, nickel, lead, selenium,
and tin are harmful pollutants, they were not found in
significant quantities.
TEMPERATURE
Excess thermal load, even in non-contact cooling water, has not
been found to be a significant problem in this segment of the
mineral mining and processing industry.
ASBESTOS
"Asbestos" is a generic term for a number of fire-resistant
hydrated silicates that, when crushed or processed, separate into
flexible fibers made up of fibrils noted for their great tensile
strength. Although there are many asbestos minerals, only five
are of commercial importance. Chrysotile, a tubular serpertine
mineral, accounts for 95 percent of the world's production. The
others, all amphiboles, are amosite, crocidolite, anthophyllite,
and tremolite. The asbestos minerals differ in their metallic
elemental content, range of fiber diameters, flexibility or
hardness, tensile strength, surface properties, and other
attributes that determine their industrial uses and may affect
their respirability, deposition, retention, translocation, and
biologic reactivity. Serpentine asbestos is a magnesium silicate
the fibers of which are strong and flexible so that spinning is
possible with the longer fibers. Amphibole asbestos includes
various silicates of magnesium, iron, calcium, and sodium. The
fibers are generally brittle and cannot be spun but are more
resistant to chemicals and to heat than serpentine asbestos.
Chrysoltile 3MgG«2SiOJ2»2H.2O
Anthophyllite (FeMg) *SiO.3»H2O
Amosite (ferroanthophyllite)
Crocidolite NaFe* (SiOj) 2«FeSiO.3«HjO
Tremolite Ca2Mg5Si8O22(OH> 2
All epidemiologic studies that appear to indicate differences in
pathogenicity among types of asbestos are flawed by their lack of
guantitative data on cumulative exposures, fiber characteristics,
and the presence of cofactors. The different types, therefore.
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cannot be graded as to relative risk with respect to asbestosis.
Fiber size is critically important in determining respirability,
deposition, retention, and clearance from the pulmonary tract and
is probably an important determinant of the site and nature of
biologic action. Little is known about the movement of the
fibers within the human body, including their potential for entry
through the gastrointestinal tract. There is evidence though
that bundles of fibrils may be broken down within the body to
individual fibrils. Effluent standards on asbestos in water are
not regulated at this time pending additional health effect data.
RADIATION AND RADIOACTIVITY
Exposure to ionizing radiation at levels substantially above that
of general background levels can be harmful to living organisms.
Such exposure may cause adverse somatic effects such as cancer
and life shortening as well as genetic damage. At environmental
levels that may result from releases by industries processing
materials containing natural radionuclides, the existence of such
adverse effects has not been verified. Nevertheless, it is
generally agreed that the prudent public health policy is to
assume a non-threshold health effect response to radiation
exposure. Furthermore, a linear response curve is generally
assumed which enables the statistical estimate of risk from
observed values at higher exposures to radiation through to zero
exposure.
The half-life of the particular radionuclides released to the
environment by an industry is extremely important in determining
the significance of such releases. Once released to the
biosphere, radionuclides with long half-lives can persist for
hundreds and thousands of years. This fact coupled with their
possible buildup in the environment can lead to their being a
source of potential population exposure for many hundreds of
years. Therefore, in order to minimize the potential impact of
these radionuclides, they must be excluded from the biosphere as
much as possible.
Facilities and animals that incorporate radioactivity through the
biological cycle can pose a health hazard to man through the food
chain. Facilities and animals, to be of significance in the
cycling of radionuclides in the aquatic environment must
assimilate the radionuclide, retain it, be eaten by another
organism, and be digestible. However, even if an organism is not
eaten before it dies, the radionuclide will remain in the
biosphere continuing as a potential source of exposure.
Aguatic life may assimilate radionuclides from materials present
in the water, sediment, and biota. Humans can assimilate
radioactivity through many different pathways. Among them are
drinking contaminated water, and eating fish and shellfish that
have radionuclides incorporated in them. Where fish or other
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fresh or maring products that may accumulate radioactive
materials are used as food by humans, the concentrations of the
radionuelides in the water must be restricted to provide
assurance that the total intake of radionuclides from all sources
will not exceed recommended levels.
RADIUM 226
Radium 226 is a member of the uranium decay series. It has a
half-life of 1620 .years. This radionuclidese is naturally
present in soils throughout the United States in concentrations
ranging from 0.15 to 2.8 picocuries per gram. It is also
naturally present in ground waters and surface streams in varying
concentrations. Radium 226 is present in minerals in the earth's
crust. Generally, minerals contain varying concentrations of
radium 226 and its decay products depending upon geological
methods of deposition and leaching action over the years. The
human body may incorporate radium in bone tissue in lieu of
calcium. Some facilities and animals concentrate radium which
can significantly impact the food chain.
As a result of its long half-life, radium 226 which was present
in minerals extracted from the earth may persist in the biosphere
for many years after introduction through effluents or wastes.
Therefore, because of its radiological conseguences,
concentrations of this radionuclide need to be restricted to
minimize potential exposure to humans.
Relatively low concentrations of radioactivity and radium 226
were found in the treated effluent for the phosphate industry.
Since the treatment is specific for suspended solids and not
radium and since removal of TSS results in removal of the latter,
only TSS will be regulated.
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SECTION VII
CONTROL ANE TREATMENT TECHNOLOGY
Waste water pollutants from the mining of minerals for the con-
struction industry 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 whenever space requirements or economics do not
preclude utilization.
In a few instances dissolved substances such as fluorides, acids,
alkalies, and chemical additives from ore processing 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 pollutants found in this
industry are complicated by several factors:
(1) the large volumes of waste water involved for many of the
processing operations,
(2) the variable waste water quantities 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,
(tt) geographical location: e.g., waste water can be handled
differently in dry isolated locations than in industrialized
wet climates.
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 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 uncommon that any noncontact cooling water, is involved in
minerals mining and processing. There are a number of areas,
however, where control is very important.
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Separation and Control of Waste water
In these industries waste water may be separated into different
categories:
(1) Mine dewatering. For many mines this is the only effluent.
Usually it is low in suspended solids, but may contain
dissolved minerals.
(2) Process water. This is water involved in transporting,
classifying, washing, beneficiating, and separating ores and
other mined materials. This water usually contains heavy
loads of suspended solids and possibly some dissolved
materials.
(3) Rain water runoff. Since mineral mining operations often
involve large surface areas, the rain water that falls on the
mine and process facility property constitutes a ma-jor
portion of the overall waste water load leaving the property.
This water 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 dewatering is 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
dewatering water or flow off the land independently as non-point
discharges.
Degradation of the mine water quality may be caused by combining
the wastewater streams for treatment at one location. A negative
effect results because water with low pollutant loading (often
the mine water) 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.
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:
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(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
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 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.
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. 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 dis-
charged from a pit area, since that water is prevented from
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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 solubili-
zation 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.
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
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determine if excessive water is likely to 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 rocf from rock formations 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 overlying rocks, as well
as joint separation far above the mine 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; (H) 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 groundwater system and then
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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.
SUSPENDED SOLIDS REMOVAL
The treatment technologies available for removing suspended
solids from minerals mining and processing waste water are
numerous and varied, but a relatively small number are widely
used. The following shows the approximate breakdown of usage for
the various techniques:
percent of treatment
facilities
removal technique using technology
settling ponds (unlined) 95-97
settling ponds (lined) <1
chemical flocculation 2-5
(usually with ponds)
thickeners and clarifiers 2-5
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:
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(1) Solids removal. Solids settle to the bottom and the clear
water overflow is much reduced in suspended solids content.
(2) Equa1i z a ti on and water storage capacity. The clear
supernatant water layer serves as a reservoir for reuse or
for controlled discharge.
(3) 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 suspended
solids, 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 settled material and the
following ones providing final polishing to reach a desired
suspended solids level. As the ponds fill with solids they can
be dredged to remove these solids or they may be left filled and
new ponds provided. 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 range from small
pits, natural depressions and swamp areas to engineered thousand
acre structures with m-.ssive retaining dams and legislated
construction design. The performance of these ponds can vary
from excellent to poor, depending on character of the suspended
particles, and pond size and configuration.
In general the current experience in this industry segment with
settling ponds shows reduction to 50 mg/1 or less, but for some
waste waters the discharge may still contain up to 150 mg/1 of
TSS. Performance data of some settling ponds found in the
dimension stone, crushed stone, construction sand and gravel, and
industrial sand subcategories is given in Table 12. Eighteen of
these 20 facility samples show greater than 95 percent reduction
of TSS by ponding. There appear to be no correlations within a
sampled subcategory due to differences in quality of intake
water, mined product, or processing. Laboratory settling data
collected on samples of the process waste water pond from six of
the sand and gravel facilities contained in the above data show
that under controlled conditions they can be settled within
24 hours to a range of 20-450 mg/1 of suspended solids, and, with
the addition of commercial coagulant can be settled to a range of
10-60 mg/1 in the same time period. These laboratory data are
consistent with the pond performance measured above.
235
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Plant
Table 12
Settling Pond Performance
Stone, Sand and Gravel Operations
TSS
(mg/1) Percent
Influent Effluent Reduction
Treatment,
Chemical
Dimension Stone
3001 1,808
3003 3,406
3007 2,178
Crushed Stone
1001
1003
1004
1021
(2 ponds)
1039
1053
Construction
Sand and Gravel
37
34
80
1391
12,700
Industrial Sand
1019 2,014
1101 427
1102 2,160
D - Dredge
A - Main Plant
B - Auxiliary Plant
18
56
56
66
97.95
99
96.3
99.86
97.22
86.88
96.94
none
FeCl_3, sodium
bicarbonate
none
1,054
7,68
5,710
7,206
772
10,013
21,760
8
8
12
28
3
14
56
99.24
99.92
99.79
99.61
99.61
99.86
99.74
none
none
none
none
none
none
none
1017 (D)
1044
1083 (A)
1083 (B)
1129
1247 (D)
5,712
5,114
20,660
8,863
4,660
93
51
154
47
32
44
29
99.12
96.99
99.77
99.64
99.06
68.82
floci
none
none
none
none
floe.
agent
none
none
none
flocculating
236
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In this industry, settling is usually a prelude to recycle of
water for washinq purposes. The level of suspended solids
commonly viewed as acceptable in recycled water used for
construction materials washing is 200 mg/1 and higher. Every
facility in the above sample achieved this level with values
ranging from 3 to 151 mg/1. Thus the TSS levels obtained after
settling in ponds are apparently under present practices
adequate for recycling purposes for these subcategories.
Much of the poor performance exhibited by the settling ponds
employed by the 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
rate 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 effectively
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
circuiting. The first can be avoided by constructing a series of
ponds as mentioned above. Frequent dredging of 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 by use of a weir.
Frequent dreding or insertion of baffles will also minimize
channelling. The EPA report "Waste Water Treatment Studies in
Aggregate and Concrete Production" in detail lists the procedure
one should follow in designing and building settling ponds.
FLOCCULATIO1S1
Flocculating agents increase the efficiency of settling
facilities. 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, thereby allowing the particles to
attract each other and agglomerate. Polymeric types function by
physically trapping 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.
237
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Agqlomeration, 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.
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
liguid in the other.
Clarifiers differ from thickeners primarily in their basic
purpose. Clarifiers are used with the main purpose of producing
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. Less land space is reguired, since these devices are
much more efficient in settling capacity than ponds. Influences
of rainfall are much less than for ponds. If desired the
clarifiers and thickeners can even be covered. Since the
external construction of clarifiers and thickeners consist of
concrete or steel tanks, ground seepage and rain water runoff
influences do not exist.
On the other hand, clarifiers and thickeners suffer some distinct
disadvantages as compared with ponds. They have more mechanical
parts and maintenance. They have only limited storage capacity
for either clarified water or settled solids. The internal
sweeps and agitators in thickeners and clarifiers reguire more
power and energy for operation than ponds.
Clarifiers and thickeners are usually used when sufficient land
for ponds is not available or is very expensive. They are found
in the phosphate and industrial sand subcategories.
238
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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
other 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. They are used in the phosphate
subcategory to dewater sand tailings and in the sand and gravel
subcategory to recover sand fines normally wasted.
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.
CENTRIFUGES
Centrifuges are not 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.
SCREENS
Screens are widely used in minerals mining and 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
239
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product. Screens are not economically practical for removing the
smaller suspended particles.
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
Unlike suspended solids which need to be removed from minerals
mining and processing waste waters, 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.
Acids and alkaline materials are examples of dissolved materials
modified in this way. Most removal of dissolved solids is
accomplished by chemical precipitation. An example of this is
given below, the removal of fluoride by liming:
2F- + Ca(OH)2 ^ CaF2 + 2OH~
With the exception of pH adjustment, chemical treatments are not
common in this industrial segment.
NEUTRALIZATION
Some of the waterborne wastes of this study, 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.
240
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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. An example of pH control being used for
precipitating undesired pollutants are:
(1) Fe+3 + 30H- ^ Fe(OH)_3
(2) Mn+2 + 20H- £ Mn(OH)j2
(3) Zn+2 + 20H- £ Zn(OH)2
(4) Pb+2 + 2 (OH)- £ Pb(OH)j2
(5) Cu+2 + 20H- # Cu(OH)^.
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 trivalent
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 wastes to make them less
troublesome. In general waste materials requiring
oxidation-reduction trea< ments are not encountered in these
industries.
Pre ci pi ta ti on s
The reaction of two soluble chemicals to produce insoluble or
precipitated products is the basis for removing many pollutants.
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. The following are examples of
precipitation reactions used for waste water treatment:
241
-------
(1) S04 = + Ca(OH)_2 # CaSOj* + 2OH-
(2) 2F- + Ca(OH).2 * CaF2 + 20H~
(3) Zn++ + NajCOJ # ZnC03 + 2Na+
EXAMPLES OF WASTE WATER TREATMENT
The following text discusses how these technologies are employed
by the subcategories covered in this document and the effluent
quality.
DIMENSION STONE
The single important water effluent parameter for this industry
is suspended solids. In dimension stone processing facilities,
water is only occassionally recycled. The following summarizes
waste treatment practices.
Stone
Mica Schist
Slate
Dolomitic
Limestone
Limestone
Granite
Marble
Facility
5600
3017
3018
3053
3039
3040
3007
3008
3009
3010
3001
3029
3038
3002
3003
3034
3051
3304
3305
3306
Waste Water Treatment
settling
100X recycle
none
settling
settling
settling
settling
settling, 100% recycle
settling
settling, 100% recycle
settling
settling
flocculants, settling,
10031 recycle
settling
settling
settling
none
settling
settling
settling, polymer, alum
At facility 3038 chemical treatment, solids separation via a
raked tank with filtration of tank underflow, plus total recycle
of tank overflow is practiced. This is necessary since the
facility hydraulic load would otherwise overwhelm the small
adjacent river. Furthermore, the facility has a proprietary
process for separating silicon carbide particles from other
solids for evential reuse. Since granite facilities are the only
users of silicon carbide, non-granite processors could not obtain
any cost benefits from this Sic recovery practice.
242
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Disposition of quarry and facility waste stone is more a function
of state requirements than of any other factor. Thus, waste
stone and settling pond solids are conscientiously used to refill
and reclaim quarries where the state has strict reclamation laws.
Corporate policy regarding disposition of solid wastes is the
second most important factor, and type and yield of stone is the
least important factor. Thus, where both state and corporate
policy are lenient, solid wastes are accumulated in large piles
near the quarry (facilities 3017, 3053, and to some extent 3051).
In addition to refilling abandoned quarries, some facilities make
real efforts to convert waste stone to usable rubble stone
(facilities 3034, 30UO), crushed stone (facilities 3051, 3038,
3018), or rip rap (facilities 3051, 3039). Successful efforts to
convert low grade stone to low priced products are seen only in
the marble, granite, and dolomitic limestone industries.
Pit pumpout does occur as a seasonal factor at some locations,
but suspended solids have generally been found to be less than 25
mg/1. The quality of mine water can be attributed more to stone
type than to any other factor. For example, granite quarry
pumpout at facility 3001 is 25 mg/1 TSS. However, limestone,
marble, and dolomitic limestone quarry water is generally very
clear and much lower in suspended solids.
Several analyses of treated effluents available are as follows:
Facility 3007 7.8 pH
7.1 mg/1 TSS (range 0-24.5)
Facility 3304 <10 JTU
Facility 3305 <100 mg/1 total solids
<5 mg/1 TSS
<1 BOD
Facility 3306 <1 JTU
Facility 3002 600 mg/1 TSS
Facility 3003 34 mg/1 TSS
Facility 3001 Water including runoff from 2
quarries
1 mg/1 TSS
4 mg/1 TSS
Finishing Facility-37 mg/1 TSS
Facility 5600 Quarry - 7 mg/1 TSS
Facility 3051 Quarry - 7 mg/1 TSS
Facility-1658 mg/1 TSS
Second Facility-4008 mg/1 TSS
CRUSHED STONE (WET PROCESSING)
In all of the facilities contacted, the effluent from the washing
operation is sent through a settling pond system prior to
discharge. This system generally consists of at least two
243
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settling ponds in series designed to reduce the suspended solids
in the final discharge. At facility 1439 the suspended solids
concentration entering the first settling pond is 7000-8000 mg/1
which is reduced to a level of 15-20 mg/1 after flowing through
the two ponds. Facility 3027 reports its settling pond system
reduces the total suspended solid level in the facility washwater
by 95 percent.
In some instances (facility 1222), flocculating agents are added
to the waste stream from the wash facility prior to entering the
first settling pond to expedite the settling of the fine
particles. Mechanical equipment may be used in conjunction with
a settling pond system in an effort to reduce the amount of
solids entering the first pond. At facility 1040, the waste
water from the washing operation flows through a dewatering screw
which reportedly removes 50 percent of the solid material which
represents a salvageable product. The waste water flows from the
screw into the first settling pond.
Facility 1039 has an even more effective method for treating
waste water from the washing operation. As with facility 1040,
the waste water flows into a dewatering screw. Just prior to
this step, however, facility 1039 injects a flocculating agent
into the waste water which leads to a higher salvage rate.
Of the facilities contacted that wash crushed stone, 33 percent
do not discharge their wash water. Many of the remaining
facilities recycle a portion of their waste water after
treatment. It should be noted that evaporation and percolation
have a tendency to reduce the flow rate of the final discharge in
many instances. The main concern with the final effluent of a
wet crushed stone operation is the level of suspended solids.
This may vary greatly depending on the deposit, the degree of
crushing, and the treatment methods employed.
The waste water from the wet scrubber in facility 1217 is sent to
the first of two settling ponds in series. After flowing through
both ponds, the water is recycled back to the scrubber with no
discharge. Effluent data from some of the facilities that do
discharge wash water after treatment by settling ponds are:
facility effluent
1004 Flow - 8.7 x 10*
I/day (2.30 mgd)
pH - 7.5
Turbidity - 16 FTU
1053 Flow - 1.8 x 10»
I/day (0.48 mgd)
pH - 8.4
Turbidity - 18 FTU
source
treated discharge composed
of wash water (4%) and
pit pumpout (96%)
wash water after treatment
244
-------
1218 Flow - 6.2 x 10* wash water after treat-
1/day (1.64 mgd) men-t then combined with
TSS - 20 mq/1 pit pumpout
Of the facilities contacted the following are achieving total
recycle of process generated waste water:
1002 1003 1039 1040 1062 1063
1064 1065 1066 1067 1068 1070
1071 1072 1079 1090 1161 1212
1220 1223 1439 3027 5663
The following facilities use a common pond for process waste
water and mine water. These facilities recycle much of this
combined pond water but discharge the remainder.
effluent
facility TSS mg/1
1001 8
1023 34
1219 2
1222
1226
1227
1228
5662 9
5664 40, 42
Many treatment ponds experience ground seepage. Facility 1974 is
an example of a facility achieving no discharge because of
seepage.
Many of the operators in this sutcategory must periodically clean
their settling ponds of the fines which have settled out from
wash water. A clamshell bucket is often used to accomplish this
task. The fines recovered are sometimes in the form of a
saleable product (facility 1215) while in most instances these
fines are a waste material. In this instance, the material is
either stockpiled or used as landfill (facilities 1053 and 1212).
The guantity of waste materials entering the pond varies for each
operator and the processes involved. Facility 1002 reports that
the washwater entering the settling ponds contains 4-5 percent
waste fines. The frequency of pond cleaning depends not only on
the processes involved but also on the size of the pond.
Facility 1217 must clean its settling ponds once per month, the
recovered material serving as landfill. The disposal of these
fines presents problems for many operators.
245
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CRUSHED STONE (MINE DEWATERING)
Pit pumpout may either be discharged directly with no treatment
(facility 1039), discharged following treatment (facilities 1020
and 5640), or discharged with the treated effluent from the
washing operation (facility 1001). In the latter case, the
guarry water may be combined with the untreated facility effluent
and then flow through a settling pond system prior to discharge
(facility 5662). The quarry water may instead join the
semi-treated effluent as flow to the second of two settling ponds
(facility 1213). There are many variations to the handling of
pit pumpout.
Mine dewatering data from several facilities of this subcategory
are:
facility TSS mg/1
1001
1003
1004
1020
1021
1022
1023
1039
1040
1214
1215
1219
1224
3319
3320
3321
5660
5661
5663
5664
3
7
12
(1)
1,
15
34
7
25
<1,
(1)
2
10-
1,
17,
5,
32,
1,
15,
14
0
1
42.
5r(2)l
1, 6, 1, 12, 2
2,3
42, (2) 28
30
1, 1, 1, 2, 4, 5, 5, 5, 9, 11, 15,
21, 35, 38, 38, 55, 64
9, 9, 10, 11, 14, 15, 19, 27, 28,
35, 65, 103, 128
2, 2, 2, 3, 3, 4, 4, 5, 6, 7, 9, 14,
17, 20, 21, 22, 22, 26, 45, 51, 67
(1) first pit
(2) second pit
CRUSHED STONE (FLOTATION)
At facility 1975, all waste water is combined and fed to a series
of settling lagoons to remove suspended materials. The water is
then recycled back to other washing operations with the exception
of about 5 percent which is lost by percolation and evaporation
246
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from the
water.
ponds. This loss is made up by the addition of fresh
At facility 3069 a considerable portion of the waste water is
also recycled. The individual waste streams are sent to settling
tanks for removal of suspended solids. From these, about 70
percent of the process water and all of the cooling and boiler
water is recycled. The remainder is released to settling ponds
for further removal of suspended solids prior to discharge.
At facility 1021, lagooning is also used for removal of suspended
solids. No recycle is practiced.
For facilities 3069 and 1021 the effluents are listed as follows
along with corresponding intake water compositions. In the case
of facility 1021 the data presented are analytical measurements
made by the contractor.
TSS
(mg/1)
BOD
(mg/1)
COD
(mg/1)
sulfate
(mg/1)
turbi-
intake
water
(3069)
1.0
1.0
3.5
10
effluent
(3069)
10
intake
water effluent
(1021) (1021)
<2.0
13
19
dity (FTU)
chloride 3.8
(mg/1)
total
solids
(mg/1)
32
4.1
128
50 20
464
154
At Facility 1044, only non-contact cooling water is discharged.
The pH of facility 1007 effluent ranges from 6.0-8.0, and the
significant parameters are:
Flow, 1/kkg of product (gal/ton) 625
TSS, mg/1 55
TSS, kg/kkg of product (1 lb/1000 Ib) 0.034
(150)
247
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SAND AND GRAVEL
The predominant method of treating process waste water is to
remove sand fines and clay impurities by mechanical dewatering
devices and settling basins or ponds. Removal of -200 mesh sand
and clay fines is much more difficult and requires settling times
that are usually not achievable with mechanical equipment. Some
facilities use settling aids to hasten the settling process. The
best facilities in this subcategory are able to recycle the
clarified water back to the process. Water with a total
suspended solids content less than 200 mg/1 is generally clean
enough to reuse in the process. The following tabulates data
from facilities which recirculate their process water resulting
in no discharge of process waste water:
Input
^Facility TSS (mg/1)
1055
unknown
1235
1391
1555
3049
5617
5631
5674
unknown
4,550
15,000
5,000
unknown
unknown
unknown
Treatment
spiral classi-
fiers, 4-hectares
(10-acre) settling
basin
Output
TSS fmq/1)
25
mechanical thick- 54
eners, settling
ponds
mechanical thick- 32
eners, cyclones,
2-hectares (5-acre)
settling basin
cyclones, 14-hectares 35
(35-acre) settling
basin
cyclones, vacuum 30
disc filter, 2-hectares
(5-acre) settling pond
with polymer floe
dewatering screws, unknown
settling ponds
dewatering screws, unknown
10-hectares (25-acre)
settling pond
dewatering screws, unknown
0.8-hectare (2-acre)
settling pond
248
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Facilities 1012 and 5666 are hydraulic dredging facilities.
Slurry from these facilities is sent to a settling basin to
remove waste fines and clays. The decant from the settling basin
is returned to the wet pit to maintain a constant water level for
the dredge resulting in no discharge of process water to
navigable waters. Facilities 3339 and 3340 likewise achieve no
discharge.
Lack of land to a major extent will impact the degree to which a
facility is able to treat its process waste water. Many
operations are able to use worked-out sand and gravel pits as
settling basins. Some have available land for impoundment
construction. The following lists the suspended solids
concentration of treated waste water effluents from facilities
discharging:
Facility Treatment TSS, mg/1
1006 dewatering screw, 55
settling ponds
1011 dewatering screw, 154
settling pond
1056 settling ponds 25
1083 dewatering screw, 47
settling ponds
1129 dewatering screw, 44
settling ponds
5630 dewatering screw, 2, 3, 4
settling ponds
Facility 1981, using heavy-media separation, recovers the
magnetite and/or ferrosilicon pulp, magnetically separates the
media from the tailings, and returns the media to the process.
Separation tailings from the magnetic separator are discharged to
settling basins and mixed with process water.
Pit pumpout and non-contact cooling water are usually discharged
without treatment. Facilities 1006 and 5630 discharge pit
pumpout water through the same settling ponds which handle
process water. Facility 1044 discharges non-contact cooling
water through the same settling ponds used for treating process
water. Dust suppression water is adsorbed on the product and
evaporated.
Half the facilities visited are presently recirculating their
process water resulting in no discharge. Those facilities
recirculating all process generated waste water include:
1007 1059 1206 1391 1235
1013 1084 1207 1555 5617
1014 1200 1208 1629 3341
1048 1201 1230 3049
249
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1055 1202 1233 5622
1056 1203 1234 5631
1057 1204 1236 5656
1058 1205 1250 5674
The following facilities achieve no discharge to navigable
waters by perculation:
1231 1232 5666 5681
The following facilities previously mentioned as recycling all
process generated waste waters . declared that significant
perculation occurs in their ponds:
1057 1058 1233 1234 5656
Facilities 1005, 1012, 5670 dredge closed ponds on their property
and discharge all process waste waters back to the pond being
dredged. Only very large rainfalls would cause a discharge from
these ponds to navigable waters. Facility 3342 discharges pit
water (never exceeding 21 mg/1 TSS) in order to maintain the pond
level.
The rest discharge process water. Characteristics of some
discharges are:
Flow TSS
1/kkg of product kg/kkg of product
Facility (gal/tonl (lb/1000 lb)
1006 2500 (600) 0.14
1044 1670 (400) 0.26
1056 1750 (420) 0.04
1083 1040 (250) 0.05
1129 1150 (275) 0.05
5630 1170 (290) 0.006
Solid wastes (fines and oversize) are disposed of in nearby pits
or worked-out areas or sold. Clay fines which normally are not
removed by mechanical equipment settle out and are routinely
cleaned out of the settling pond. Facilities 1391 and 1629
remove clay fines from the primary settling pond, allow them to
drain to approximately 20 percent moisture content, truck the
wastes to a landfill site, and spread them out to enhance drying.
SAND AND GRAVEL (DREBGING-ON LAND PROCESSING)
At dredge 1009, there is no treatment of the sand slurry
discharged to the river. Removal of waste fines at land
facilities with spiral classifiers, cyclones, mechanical
thickeners, or rake classifiers and settling basins, is the
method of process waste water treatment. These are similar to
250
-------
methods used in the wet processing subcategory. Facilities 1046,
1048, 1051 and 1052, by utilizing mechanical devices and settling
basins, recirculate all process water thereby achieving no
discharge. The following is a list of treatment methods, raw
waste loads, and treated waste water suspended solids for these
operations:
Paw Waste Load,
Facility TSS (mg/1)
Treated Recycle
Water,
TSS (mg/1)
275
Treatment
1046 8,500 dewatering
screw, cyclone,
drag classi-
fier, settling
basin
1048 10,000 dewatering 50
screw,
cyclones,
settling basins
1051 9,000 dewatering 300
screw, drag
classifier,
settling basin
1052 7,500 dewatering 200
screw, drag
classifier,
settling basin
with flocculants
Availability of land for settling basins influences the method of
process water treatment. Many operations use worked-out sand and
gravel pits as settling basins (Facility 1048) or have land
available for impoundment. Facility 1010 is not able to
recirculate under current conditions due to lack of space for
settling basins. Land availability is not a problem at
facilities 1011 and 1009. Sand fines (+200 mesh) are removed
with mechanical devices and conveyed to disposal areas. Clay
fines and that portion of the silica fines smaller than 200 mesh,
which settle out in a settling basin, are periodically dredged
and stockpiled. Facility 1051 spends approximately 120 days a
year dredging waste fines out the primary settling pond. These
fines are hauled to a landfill area. Non-contact cooling water
is typically discharged into the same settling basins used for
treating process water. Dust suppression water is adsorbed onto
the product and evaporates. Effluent parameters at facilities
1010 and 1009 are:
251
-------
TSS TSS, kq/kkq of product
Facility mg/1 (lb/1000 Ib)
1010 16,000 22
1009 50 0.10
INDUSTRIAL SAND (DRY)
Scrubber water at facility 1107 is treated in a settling pond
where suspended solids are settled and the clarified decant is
returned to the scrubber, resulting in no discharge. Facility
1108 discharges wet scrubber water without any treatment at
166,000 I/day (43,000 gpd) and 33,000 mg/1 TSS. Solid waste
(oversize and sand fines) at all of the facilities is landfilled.
INDUSTRIAL SAND (WET)
Under normal conditions facilities 1019, 1989, and 3066 are able
to recirculate all process water by using clarifiers and pond the
sludge. During periods of heavy rainfall, area runoff into the
containment ponds cause a temporary discharge. Facility 1102
discharges process water, including wet scrubber water, after
treatment in settling ponds. The treatment methods used by the
facilities are shown as follows:
Facility Treatment
1019 thickener, clarifier, settling
pond, recycle
1102 cyclone, thickener and floccu-
lant, settling ponds
1989 settling pond and recycle
3066 settling pond and recycle
INDUSTRIAL SAND (FLOTATION)
At the acid flotation facilities, facilities 1101, 1019, 1980,
and 1103, all process wash and flotation waste waters are fed to
settling lagoons in which muds and other suspended materials are
settled out. The water is then recycled to the process.
Facilities 1101 and 1980 are presently producing products of a
specific grade which allows them to totally recycle all their
process water. In two other facilities, facilities 1019 and
1103, all facility waste waters leave the operations either as
part of a wet sludge which is land disposed or through
252
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percolation from the settling ponds. There is no point source
discharge from any of the acid flotation operations.
At the alkaline flotation facility 5691, the washwaters are
combined and fed to a series of settling lagoons to remove
suspended materials and then partially recycled. Alum is used as
a flocculating agent to assist in settling of suspended
materials, and the pH is adjusted prior to either recirculation
or discharge.
At facility 5980, the only facility found that uses HF flotation,
all waste waters are combined and fed to a thickener to remove
suspended materials. The overflow containing 93.2 percent of the
water is recycled to the process. The underflow containing less
than 7 percent of the water is fed to a settling lagoon for
removal of suspended solids prior to discharge. The pH is also
adjusted prior tc discharge. Fluoride ion concentration in the
settled effluent ranges from 1.5 to 5.0 mg/1. The composition of
the intake and final effluent waters for the alkaline flotation
facility 5691, and the HF flotation facility 5980 are presented
as follows.
Pollutants Facility 5691 Facility 5980
(mq/1) Intake Effluent Intake Effluent
pH 7.8 5.0 7.6 7.0-7.8
TDS 209 192
TSS 5 4 10 5,47
Sulfate 9 38 285 27-330
Oil and Grease <1.0 <1.0
Iron 0.1 0.06
Nitrate 23 0-9
Chloride 62 57-76
Fluoride 0.8 1.8,6.6
Phenols Not detectable
GYPSUM
Mine or quarry pumpout is generally discharged without treatment.
Most facilities discharge non-contact cooling water without
treatment. Effluent data for some facilities discharging mine or
guarry water are given as follows:
253
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facility
1041
1042
1110
1112
1997
1999
flow, 10*
I/day (mgd)
4.4 (1.17)
6.4 (1.70)
.19 (0.05)
5.1 (1.35)
0.68 (0.18)
6.5 (1.71)
6
4
60
14
5
24
7.7
7.8
7.8
8.1
7.9
7.4
Non-contact, cooling water discharge from these facilities is
given below:
facility
1041
1042
1112
1997
1999
flowfl/kkg of
product (gal/ton)
none
246 (59)
none
250 (60)
4.5 (1)
not known
6
130
not known
7.9
5
Land plaster dust collected in cyclones is either recycled to the
process or hauled away and landfilled.
All process water used for heavy media separation at facility
1100 and the one other facility in this subcategory is re-
circulated through settling basins, an underground mine settling
sump, and returned to the separation
discharge of process waste water.
HMS media (magnetite/ferrous silica)
in the separation process.
circuit, resulting in no
In the recycle circuit, the
is reclaimed and is reused
Part of the waste rock from the HMS is sold as road aggregate,
with the remainder being landfilled in old worked-out sections of
the guarry. Waste fines at facility 1100 settle out in the
primary settling basin and must be periodically dredged. This
waste is hauled to the guarry and deposited.
BITUMINOUS LIMESTONE
No water is used in these operations hence there is no effluent.
OIL IMPREGNATED DIATOMITE
All scrubber water at facility 5510 is completely recycled; hence
there is no process waste water discharge.
GILSONITE
The compositions of the intake water, the discharged facility
process water and the mine pumpout water are listed below. There
254
-------
is a considerable concentration of suspended solids in the mine
pumpout water. These discharges are currently being eliminated.
The process and mine pumpout waters currently discharged at
facility 5511 will soon be employed on site for other purposes.
Concentration (mq/1)
intake effluent mine pumpout
Suspended solids
BOD
PH
TDS
Turbidity
Arsenic
Barium
Cadmium
Chloride
Sulfate
33
35
7.7
401
17
43
8.2
2949
<0.001
0.15
363
ASBESTOS
3375
12
7.9 - 8
620
70 JTU
0.01
<0.01
0.004
8.8
195
Facility 3052 treats the quarry pumpout discharge with sulfuric
acid (approximately 0.02 mg/1 of effluent) to lower the pH of the
highly alkaline ground water that collects in the quarry. The
following tabulates the analytical data for this discharge:
flow, I/day (mgd)
TSS, mg/1
Fe, mg/1
PH
asbestos (fibers/liter)
545,000-3,270,000 (0.144-0.864)
2.0
0.15
8.4-8.7
1.0 - 1.8 x 10*
At all facilities, both at the mine and facility site, there
exists the potential of rainwater runoff contamination from
asbestos waste tailings. Facility 1061 has constructed diversion
ditches, berms, and check dams to divert and hold area runoff
from the waste tailing pile. Due to soil conditions, water that
collects in the check dams eventually percolates into the soil
thereby resulting in no discharge to surface waters.
At the wet processing facility the process water discharge is
treated in settling/percolation ponds. Suspended asbestos fibers
settle out in the primary settling pond prior to decanting the
clarified effluent to the secondary settling/percolation pond.
Facility 1060 does not discharge to surface waters. Non-contact
cooling water is not treated prior to discharge. Runoff from
asbestos tailings at the facility and the quarry is controlled
with diversion ditches, berms, and check dams. All facility
drainage is diverted to the settling/percolation ponds. Data on
the waste stream to the percolation pond includes the following:
255
-------
Intake Discharge to
Well Water Percolation Pond
flow, 1/kkg feed (gal/ton) unknown 856 (205)
total solids, mg/1 313 1,160
pH 7.5 7.8
magnesium, mg/1 14 48
sodium, mg/1 44 345
chloride, mg/1 19 104
nickel, mg/1 0.02 0.1
Asbestos fiber tailings are stockpiled near the facility where
the water is drained into the settling/percolation ponds. After
some drying, the tailings are transported and landfilled near the
facility in dry arroyos or canyons. .-„ Check dams are constructed
at the lower end of these filled-in areas.
The primary settling pond must be periodically dredged to remove
suspended solids (primarily asbestos fibers). This is done with
a power shovel, and the wastes are piled alongside the pond,
allowed to dry, and landfilled.
WOLLASTONITE
Non-contact cooling water is discharged with no treatment to a
nearby river. There is no process waste water.
PERLITE
There is no water used.
PUMICE
At all facilities except facility 1705, there is no waste water
to be treated. At facility 1705, the scrubber water is
discharged to a settling pond for removal of suspended materials
prior to final discharge. Facility 1705 operates on an
intermittent basis, and no information is available on the
composition of its discharge. This facility produces less than
0.1 percent of U.S. pumice.
VERMICULITE
Both vermiculite operations have no discharge of waste waters.
At facility 5506, the waste stream is pumped to a series of three
settling ponds in which the solids are impounded, the water is
clarified using aluminum sulfate as a flocculant, and the clear
water is recycled to the process facility. The only water escape
from this operation is due to evaporation and seepage from the
pond into ground water. The overburden and sidewall waste is
returned to the mine upon reclamation.
256
-------
At facility 5507, the waste streams are pumped to a tailings pond
for settling of solids from which the clear water underflows by
seepage to a reservoir for process water to the process facility.
Local lumbering operations are capable of drastically altering
water runoff in the watersheds around the mine. This requires
by-pass streams around the ponding system.
MICA AND SERICITE (WET GRINDING)
At facility 2055, the raw waste stream is collected in surge
tanks and about 20 percent of the decanted water is recycled to
the process. The remainder is pumped to a nearby facility for
treatment. The treatment consists of adding polymer,
clarification and filtration. The filter cake is stockpiled and
the filtrate discharged. At facility 2059, the waste stream
flows to settling tanks. The underflow from the - settling tanks
is sent back to the process for mica recovery. The overflow goes
into a 0.8 hectare (2 acre) pond for settling. .The decanted
water from this pond is recycled to the process. However, during
heavy rainfall, the settling pond overflows.
MICA (WET BENEFICIATION)
In facilities 2050, 2051, 2053, and 2058 the wastes are treated
by settling in ponds, and the supernatant from the last pond is
recycled to the facility. The sizes of the ponds used at each
facility are given as follows.
Facility hectares acres
2050 7.3 18
2051 3.2 8
2053 0.8, 1.6, 2.8 2, 4, 7
2058 8.1 20
During normal operations there is no discharge from ponds 2050
and 2051. However, these ponds discharge during exceptionally
heavy rainfalls (4" rain/24 hours). The only discharge at
facility 2058 is the drainage from the sand stockpiles which
flows into a 0.4 hectare (1-acre) pond and discharges.
At facility 2054 waste water is treated in a 1.2 hectare (3-acre)
pond. This facility
plans to convert
the water flow system of this operation to a closed circuit "no
discharge" process by the addition of thickening and filtration
equipment.
At facilities 2052 and 2057 the waste water is treated in a
series of ponds and the overflow from the last pond is treated by
lime for pH adjustment prior to discharge. Facility 2052 has
three ponds of 1.2, 1.6, and 3.6 hectares (3, 4, and 9 acres.
257
-------
respectively) in size. In addition to mica, these two facilities
produce clay for use by ceramic industries. According to
responsible company officials, these two facilities cannot
operate on a total water recycle basis. The amine reagent used
in flotation circuits is detrimental to the clay products as it
affects their viscosity and plasticity. The significant
constituents in the effluent from these facilities are given
below:
facility
2052
2054
2057
6-9
400
4.3
6.5
pH before lime
treatment 4.2
pH after lime treatment 6.5
TSS, mg/1 20
TSS, kg/kkg 1.5 <1.3
settleable solids,
ml/liter <0.1 <0.1 <0.1
BARITE (WET)
The waste water streams are combined and sent to settling ponds
and the reclaimed water from the ponds is recycled to the washing
facilities. At facilities 2012 and 2046, the overflow from the
settling pond percolates through gravel piles amassed around the
settling pond, and enters clarification ponds. The supernatant
water from the clarification pond is then recycled to the
facilities for reuse. Also, in these facilities (2012 and 2046),
there are several small ponds created around the main impoundment
area to catch any accidental overflow from the clarification
ponds. Besides ponding, facilities 2015 and 2016 also use
coagulation and flocculation to treat their process waste water.
A summary of the treatment systems for the barite facilities in
this subcategory follows:
Facility Discharge
2011
2012
Source
2013
2015
2016
Intermittent* Mill tailings,
runoff
Intermittent* Well water
from clear
water pond
None from Mill tailings
tailings pond
None
Intermittent*
Mill tailings
Mill tailings,
runoff
Intermittent* Mill tailings.
Treatment
Pond recycle,
18 ha (45 ac)
Pond 8 ha
(20 ac)
Pond, 36 ha
(90 ac)
Clarification
Pond, recycle
Pond, recycle
Pond, coagulation
Flocculation,
recycle
Pond, coagulation
258
-------
2017 Intermittent*
2018 Intermittent*
2020 Intermittent*
from clear
water pond
None from
settling pond
20U6 Intermittent*
; from clear
pond
None from
tailings pond
2112 None
runoff
Mill tailings,
runoff
Mill tailings,
runoff
Well water
Mill tailings
Well water
Mill tailings
Slime Pond
Flocculat ion r
recycle
Pond, recycle
Pond, recycle
Pond 2U ha
(60 ac)
Pond, 2 ha
(6 ac)
Pond, 12 ha
(30 ac)
clarification
Pond, recycle
Pond recycle
*Indicates overflow due to heavy rainfall.
In normal circumstances, there is no effluent discharge from any
of these facilities. During heavy rains six facilities (2011,
2015, 2016, 2017, 2018 and 2020) have an overflow from the
impoundment area. Facilities 2012 and 2046 have no overflow from
their tailings impoundment area. However, during heavy rainfall,
they do have overflow from clear water ponds. Due to its
geographical location, facility 2013 has no pond overflow. The
amounts of these intermittent discharges are not known. Data
concerning tailings pond effluent after heavy rainfall was
obtained from one facility. The significant constituents in this
effluent are reported as follows:
Facility
PH
TSS, mg/1
Total barium,
mg/1
Iron, mg/1
Lead, mg/1
2011
Daily Avg. - Max.
6.0
15
0.1
0.04
0.03
- 8.0
32
- 0.5
- 0.09
- 0.10
BARITE (FLOTATION)
Wastewater is treated by clarification and either recycled or
discharged. A summary of the treatment systems is given as
follows:
259
-------
Facility Discharge
Source
Treatment
2010 Intermittent
Intermittent
2011 None
None
2019 Intermittent
Mill tailings
Runoff, spills,
washdown water
Mill tailings
Washdown water
Mill tailings
Pond, recycle
Pond
Pond, evapora-
tion and seepage
Pond, evapora-
tion and seepage
Pond
1 Indicates overflow due to heavy rainfall
2 Overflow by facility to maintain pond level
Facility 2010 has two ponds with a total capacity of 16 hectares
(40 acres) to handle the process waste water. The flotation
tailings are pumped into one of the ponds and the clear water is
pumped to the other pond. The mill tailings water is in closed
circuit, with occasional overflow from the tailings pond. This
overflow depends upon the amount of surface water runoff from
rainfall and the amount of evaporation from this pond. The
overflow varies from 0 to 760 1/min (0 to 200 gpm). At times,
there is no overflow from this pond for a year or more. The
clear water pond catches the surface runoff water, spills from
the thickener, water from use of hoses, clear water used in the
laboratory, etc. This pond has also an intermittent discharge
varying from 0 to 380 1/min (0-100 gpm). The significant
constituents in these effluent streams are as follows:
Waste
Material
Tailings Pond
Daily Average
Max. Cone.
(mg/1)
Amount
kg/day (Ib/day)
Clear Water Pond
Daily Average
Max. Cone.
(mg/1)
TSS
IDS
Ammonia
Cadmium
Chromium
Iron, total
Lead, total
Manganese,
total
Nickel, total
Zinc, total
3-5
800-1271
<0.1-0.1
0.004-0.008
0.200-0.400
0.030-0.060
0.020-0.080
0.002-0.008
0.030-0.070
0.005-0.010
1.8
467
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
(3.5)
(934)
(D
fi'j
(1)
(D
(1)
(1)
(1)
3-6
1000-1815
5-35
0.100-0.120
0.030-0.070
0.040-0.090
0.004-0.008
0.030-0.070
0.030-0.090
260
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At facility 2014, there are no effluent discharges from the
property. The mill tailings and the spent brine from the water
softening system are pumped into the tailings settling pond and
the washdown of the floors is pumped to a separate pond. These
ponds eventually dry by evaporation and seepage. This facility
has no problem in terms of pond overflow due to its geographical
location.
At facility 2019, process waste water is collected into a large
pipe which crosses under the nearby river into a 40 hectare
(100 acre) pond. The pond water pH is maintained at about 7.2 by
application of lime. An overflow is necessary from this pond to
maintain a constant pond elevation. The discharge from this pond
is intermittent. Of the 4,731,000 I/day (1.25 mgd) input to the
pond, there is an estimated 3,785,000 I/day (1.0 mgd) percolation
through the pond berm. The pond berm is built primarily of river
bottom sands. On a regular discharge basis (9 hours a day and 4
1/2 days per week operation), the effluent discharge from this
facility would be 9*6,000 I/day (250,000 gal/day). This pond is
seven years old and has an estimated life cycle of
eighteen years. When overflow to the river is desired, lime and
ferric chloride are used to decrease suspended solids. It has
been reported that the average TSS concentration in this effluent
is 250 mg/1.
BAPITE (MINE DEWATERING)
There is one underground mine in this category at facility 2010.
The other mining operations are in dry open pits. The
underground mine workings intercept numerous ground water
sources. The water from this mine is directed through ditches
and culverts to sumps in the mine. The sumps serve as
sedimentation vessels and suction for centrifugal pumps which
discharge this water to the upper level sump. This mine water is
neutralized with lime (CaO) by a continuously monitored automated
system for pH adjustment and sent to a pond for gravity settling
prior to discharge into a nearby creek. The discharge from this
mine is estimated to be 897,000 I/day (237,000 gal/day).
The raw waste from the mine has a pH of about 3.0. The pH is
raised to 6-9 by addition of lime and then pumped into a pond for
gravity settling. There are currently two ponds, and a third
pond is under construction to treat the mine discharge.
Presently one of these ponds is in use and the other one is being
excavated and cleaned so that it will be ready for use when the
first pond is filled.
The significant constituents in this effluent are reported to be
as follows:
261
-------
Parameter
New
Facility Pond
Data Design
Verification
Sampling
PH
Acidity
Hardness
TDS
TSS
SO4
Fe, total
Fer dissolved
Al
Pb
Mn
Ni
Zn
23
2.6
0.6
0.06
1.3
0.05
0.01
25
0.5
0.1
0.1
0.5
0.05
0.1
2.6
ao«»
3920
4348
1167
1515
225
177
13.8
>0.2
156
1.52
2.1
The facility stated that the verification data reflect new acid
seepage from adjoining property. The column "new pond design
"represents the company's design criteria for building the third
pond.
FLUORSPAR (HMS)
At four facilities (2004, 2005, 2006 and 2008) process water from
the thickener is pumped to either a holding pond or reservoir,
and then back to the facility on a total recycle basis. At
facility 2009, there are four ponds to treat the HMS tailings.
Three of these ponds are always in use. The idle pond is allowed
to dry and is then harvested for settled fluorspar fines. There
is no discharge from this facility. At facility 2007 the HMS
tailings enter a 1.8 hectare (U.5 acre) pond which has eight days
of retention capacity. The water from this pond is then
discharged. The significant constituents in the effluent from
facility 2007 is given as follows:
Waste Components
Fluoride
TSS
Lead
Zinc
PH
kg/kkg of product
(lb/1000 Ib)
3.0
10.0
0.015
0.09
7.8
FLUORSPAR
,04
,13
,0002
.0012
(FLOTATION)
262
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The waste water of the facilities in this subcategory is treated
in settling and clarification ponds. At facility 2000, the mill
tailings are pumped into a 7 hectare (17 acre) settling pond for
gravity settling. The overflow from the settling pond flows into
three successive clarification ponds of 2.8, 1.6, and
2.U hectares (7, U, and 6 acres, respectively). The effluent of
the third clarification pond is discharged. Settling in the
third clarification pond is hindered by the presence of carp and
shad which stir up the sediments. Experiments are in progress
using a flocculant in the influent line of the second
clarification pond to reduce the total suspended solids in the
effluent. These clarification ponds are situated below the flood
stage level of the nearby river, and during flood seasons, the
water from the river backs into the ponds. Some mixing does
occur but when flood waters recede, but it is claimed that most
of the sludge remains in the ponds.
At facility 2001, the tailings from the fluorspar rougher
flotation cells, are pumped into a settling pond from which the
overflow is discharged. Facility 2001 has a new H hectare
(10 acre) clarification pond with a capacity of approximately
106 million liters (28 million gallons). The effluent from the
first settling pond will be pumped to the new clarification pond.
A flocculant will be added to the influent of the new pond in
quantities sufficient to settle the suspended solids to meet the
state specifications (TSS 15 mg/1). A portion of the water from
the clarification pond (approximately 20 percent) will be
recycled to the processing facility and the remainder which
cannot te recycled will be discharged.
Total recycle operation has been attempted on an experimental
basis by one of these operations for a period of eight months,
without success. The failure of this system has been attributed
to the complexity of chemical buildups due to the numerous
reagents used in the various flotation circuits.
The non-contact cooling water and the boiler blowdowns are
discharged at facility 2001 without treatment. Facility 2000
includes these wastes in the process waste water treatment
system. Facility 2003 mines an ore which is different from the
ores processed in the other two facilities. This facility
produces only fluorspar. The tailings from the mill go to two
settling ponds in series. The overflow from the second settling
pond is sent to the heavy media facility, and there is no
discharge. A new pond is being constructed at facility 2003.
Effluents reported by facilities 2000 and 2001 for their current
operation and anticipated performance are:
263
-------
concentration (mg/1)
2000 2001
Current Antici- Current Antici-
operation pated operation pated
PH
TSS
Fluoride
7.2
500
5.1
TSS
Fluoride
no change 8.2
30-60 1,800
5.1 9.8
no change
15-20
9.8
kg/kkg of product (lb/1000 Ib)
2000 2001
Current Antici- Current
operation pated
Antici-
operation pated
i».8 0.29-0.57 3U. H 0.29-0.38
0.05 0.05 0.19 0.19
Additional sampling are by concentration (mg/1)
pH
Alkalinity
Hardness
TSS
TDS
F
Fe (total)
Cd
cr
Cu
Pb
Mn
Zn
FLJUORSPAR (MINE DEWATERING)
Presently at only three mines the effluent stream is discharged
with any treatment (2085, 2091 and 2092). Only effluent from
mine 2091 passes through a very small pond, 0.1 hectare
(1/4 acre), prior to being discharged into a creek. Table 13
summarizes the effluent quality of several mine dewatering
operations. Hydrogen sulfide concentrations up to 0.37 mg/1 have
been detected in the effluent, of mine 2085. It has been reported
that the H2S content in the effluent has been steadily decreasing
since an H2S pocket was encountered.
SALINES (ERINE LAKES)
264
-------
TABLE 13
FLUORSPAR MINE DEWATERING DATA
2085
settling
r\i
cr»
en
mg/1
PH
Alkalinity
Hardness
Cl
TSS
TDS
S04
F
Fe
Pb
Mn
Zn
2080
8.1
38
469
1.4
.03
0.7
2081
10
697
35
2.4
1.0
0.1
0.16
0.03
2082
7.1
8
400
1.4
.02
.08
2083
7.6
224
336
35
2-12
478
107
1.3
0.05
< 0.2
0.05
0.76
mine
7.6
276
1600
185
15
3417
480
0.66
< 0.2
0.05
< 0.01
pond
7.4
216
1600
162
29
1753
575
2.75
0.26
<0.2
0.62
2086
245
12
1.7
.05
.03
0.34
2088
7.7
20
1078
2.3
.03
0.54
2089
8.1
864
221
48
122-135
583
61
1.4
2.0
< 0.2
0.11
0.06
2090
7.7
4-69
536
56
2.3
0.05
< 0.2
0.01
0.5
2091
7.2
10
3.2
.05
0.9
0.2
mine
7.9
210
235
23
53
379
38
1.33
< 0.2
0.18
0.17
poi
8.0
197
222
17
20
364
32
1.6
0.50
< 0.2
0.18
0.08
-------
As the evaporation-crystallization process involves only recovery
of salts from natural saline brines, with the addition of only
process water, the only wastes are depleted brines and end
liquors which are returned to the salt body without treatment.
BORAX
Present treatment consists of percolation-proof evaporation ponds
with no discharge.
POTASH
All waste streams from the sylvinite facilities are disposed of
in evaporation ponds with no discharge. At the langbeinite
facilities 20-30 percent of the cooling water is evaporated. All
the process waste water from the langbeinite purification
facilities are fed to evaporation ponds with no discharge. All
known deposits of sylvinite and langbeinite ore in the U.S. are
located in arid regions.
TRONA
Process waste waters go to tailings separation ponds to settle
out the rapidly settling suspended materials and then to the
final disposal ponds which serve as evaporation ponds. Where
process water discharge takes place (at present only facility
5933), the overflow is from these latter ponds. Facility 5933
has plans to eliminate this discharge. The ground water and
runoff waters are also led to collection ponds where settling and
large amounts of evaporation take place. The excess of these
flows at the 5962 and 5976 facilities is discharged.
Evaporation of the saline waste waters from these facilities
takes place principally in the summer months since the ponds
freeze in the winter. The net evaporation averaged over the year
apparently requires an acre of pond surface for each 2,000 to
4,000 gal/day (equivalent to 19,000 to 37,000 I/day per hectare)
based on present performance.
There is no discharge from facility 5999. Facility 5976 only
mines ore and discharges only mine water. The facility 5962
discharge is only ground and runoff waters. The waste
constituents after treatment of the discharge at 5933 were at the
time of permit application:
266
-------
mg/1
kg/day (Ib/dav)
total solids 9,000
dissolved solids 8,300
suspended solids 700
860 (1,900)
793 (1,750)
67 (150)
SODIUM SULFATE
There are no discharges due to total evaporation at the arid
locations involved.
ROCK SALT
Generally there is no treatment of the miscellaneous saline waste
water associated with the mining, crushing and sizing of rock
salt. Some of the facilities have settling ponds. Facility 4028
is unique in that the mine shaft passes through an impure brine
aquifer and entraps hydrogen sulfide gas. The seepage from this
brine stream around the shaft is contained by entrapment rings.
The solution is filtered, chemically treated and re-injected into
a well to the aquifer.
The effluents from these facilities consist primarily of waste
water from the dust collectors, miscellaneous washdown of
operating areas, and mine seepage. The compositions of some of
the facility effluents expressed in mg/1 are as follows:
Facility
4013 4,(
4026
4027 !
4033
4034 (001) 306,000
(002b) 522,000 138,000
Volume
I/day gal/day
,000
,000
,000
,000
,000
1,080,000
40,000
132,000
20,200
81,000
TDS
mg/1
4,660
30,900
—
30,200
53,000 -
112,000
TSS pH
mq/1
trace*
72 7.5
150 6.5
trace**
470 - 8.5-9.0
319,000 - 1,870
323,000 4,750
7.6
* due to dilution
** runoff only, remainder of waste re-injected to well.
The suspended solids content in the process water discharges from
facilities 4013, 4026, and 4027 range up to 0.02 kg/kkg of
product. At least one of these facilities discharges an average
of as little as 0.002 kg/kkg of product.
267
-------
PHOSPHATE
Some facilities use well water for pump seal water (>2000 gpm)
claiming that this is necessary in order to protect the seals.
Others, facility U015 for example, use recycled slime pond water
with no problems. Some facilities also claim that well water is
necessary for air scrubbers on dryers in order to prevent nozzle
plugging and utilize the cooler temperature of the well water to
increase scrubber efficiency. Other facilities also recycle this
with no apparent difficulty. Facility U018 recycles this water
through a small pond that treats no other wastes.
The treatment of the process waste streams consists of gravity
settling through an extensive use of ponds. The slimes which are
common to all phosphate ore beneficiation processes, although
differing in characteristics, are the major waste problem with
respect to disposition. The slimes at 3-5 percent solids either
flow by gravity via open ditch with necessary lift stations or
are pumped directly to the settling ponds. The pond overflow is
one of the primary sources of the recycle process water. Those
facilities that include flotation discharge sand tailings at
20-30 percent solids to a mined out area. Settling occurs
rapidly with a part or all of the water returned to recycle and
the solids used in land reclamation. The pond sizes are guite
large, 160 hectares (400 acres) being typical. A single process
facility will have several such ponds created from mined areas.
Because the slimes have such a great water content, they will
occupy more space than the ore. Hence dams need to be built in
order to obtain more volume. Because of past slime pond dam
breaks, the construction of these dams is rigorously overseen in
the state of Florida. The treatment of the mine pit seepage and
dust scrubber slurries are handled similarly to the other waste
streams. Facility U003 discharqes some of the mine pumpou-t.
Effluents are intermittently or continuously discharged from one
or more settling areas by all of the beneficiation facilities.
Volumes of effluents are related to: (1) % recycle; (2) frequency
of rainfall; (3) surface runoff; and, (H) available settling pond
acreage. The pH of the effluents from these facilities range
from 6.2 to 9.1 with over 70 percent of the averages between 7
and 8.
Sufficient data was available from the Florida phosphate and
processing facilities to use statistical methods. For a given
plant normal and logarithmic normal distributions were tested on
the individual daily values for TSS and the monthly averages for
TSS. It was found that a three parameter logarithmic normal
distribution best fit the data. Figure 57 plots log TSS (mg/1)
versus probability for one facility. At higher values of Tau,
the TSS values fit a straight line determined by a least squares
program very well.
268
-------
FIGURE 57
Normal Distribution of Log TSS
for a Phosphate Slime Pond Discharge
2%
PERCFNTA'CC
40 !)0 CO
269
-------
The following data summarize the results of the statistical
analyses:
PHOSPHATE EFFLUENT QUALITY
TSS, mg/1
Lonq
Term
Average
4002
4004A(1)
4004A(2)
40048(1)
4004B(2)
4004B(3)
400 5A
4005B(1)
4005B(2)
4005C(1)
4005C(2)
4005C(3)
4015(1)
4015(2)
4015(3)
4016
4018
4019A
4019B
4019C
4020A
4020B
9.2
9.7
11.3
13.5
3.5
2.5
18.1
18.7
16.0
13.2
15.0
28.2
15.8
46.5
14.9
7.4
158
7.0
5.6
6.3
2.8
5.5
Monthly 99
Percentile
38.6
17. 4
70.3
7.3
8.1
35.5
28.7
25.7
29.4
20.7
190.8
17,5
798
17.3
24.5
36.2
6.8
7.0
Observed
Maximum
Monthly
Average
26
14
-
53
6
5
29
25
22
23
-
-
18
109
-
13
453
13
18
17
5
6
Daily 99
Percen-
tile
220
50.7
47.3
68.5
16. 1
8.5
59.8
56.4
38
44.6
75.9
116.1
39
303
24.0
20.2
1334
43.1
33.3
54.0
21.1
12.3
Observed
Daily
Maximum
64
50
30
103
12
10
75
67
35
47
55
105
36
181
20
17
1072
41
43
14
12
Some caution must be exercised when reviewing the data. For
instance some of the data noted are weekly composites and it can
be expected that the daily variability will be somewhat higher.
Some of the analyses, on the other hand, were performed on less
than 12 data points. This was the case for some monthly data.
In other cases poor sampling techniques were employed by the
facilities, and some data were not analyzed because of facility
admissions of improper sampling. In other cases high TSS values
resulted from erosion of the earthen discharge ditches or the
inclusion of untreated facility and road surface runoff.
270
-------
In addition to TSS, the slimes from beneficiation and facility
effluents contain radium 226 resulting from the presence of
uranium in the ores. Typical radium 226 concentrations in slimes
and effluents are presented in the following table:
Radium 226 Concentrations (pCi/liter)
Slime Discharge
Facility dissolved undis- g/liter
Effluent Discharge
discharge dissolved undis-
solved
point
solved
1*005
U015
4016
4017
0.82
4.8
2.0
0.60
10.2
1074
97.6
37.7
*82
0.48
*86
14.8
3.2
3.85
A-4*
K-4*
K-8*
002*
003*
001*
001
0.66
0.52
0.68
0.02
0.34
2.2
0.24
0.26
0.28
0.28
0.56
1.1
0.74
0.74
*4 hour composite sample
The concentration of total radium 226
related to the concentration of TSS.
appears to be directly
The treatment of the process waste stream for the Western
operations consists typically of flocculation and gravity
settling with some facilities having a thickening stage prior to
ponding. The slimes consist primarily of fine clays and sands.
At facility 4022, the flotation tailings (primarily sands) are
combined with the slimes with treatment common to the other
operations. The waste slurries vary in percent solids from 5 to
15. Generally a flocculating agent is added before pumping to a
thickener or directly to a settling pond where the solids settle
out rapidly.
Of the six facilities surveyed, only facility 4022 currently has
a discharge. Some part of the overflow and seepage from the
settling pond flows into a small retention basin which
occasionally discharges. This facility received a discharge
permit stipulating no discharge and intends to have complete
recycle and/or impoundment of process water.
SULFUR (FRASCH - ANHYDRITE)
There are no process waste waters emanating from these
facilities. The only waste from these facilities is sludge which
originates from the water purification operation, and it is sent
to a thickener where as much water as possible is reclaimed for
271
-------
recycling back to the system. At facility 20 2C approximately
90 percent of the thickener sludge is used as an additive to the
mud that is injected into the ore body in order to improve the
thermal and hydrologic efficiency of the mine. The remaining
10 percent is pumped into a settling pond for evaporation. At
facility 2095, the entire thickener sludge is used as drilling
mud.
SULFUR (FRASCH - SALT DOME)
The major waste from the sulfur mines is the bleedwater from the
formation. Due to the nature of the mining operation, it is not
possible to significantly reduce the quantity of the bleedwater
produced. Large aeration ponds are considered to be the best
technology available for treating the water from the bleed wells.
However, due to the scarcity of land space for ponds near some of
these mines, each facility uses a unique treating system to
reduce the hydrogen sulfide and suspended solid concentrations in
the bleedwater effluent streams.
There are four waste streams at facility 2021. Outfalls #1
(power facility effluent), #2 (sludge from the domestic water
treating facility), and #5 (water from sealing wells,
miscellaneous sanitary waste and drips and drains) are disposed
of in a seawater bay leading into the Gulf without any treatment.
Outfall #3 (bleedwater) is first flashed into a large open top
tank which causes reduction in hydrogen sulfide concentrations.
After a short residence in the tank, this effluent is mixed with
seawater to effect further oxidation of the hydrogen sulfides to
sulfates and to dilute it before discharge. A flash stripping
and oxidation system was chosen for this facility primarily
because of a new procedure of up-flank bleeding which precluded
the continued use of the existing treatment reservoir.
The location of mine 2022, some 9.6 to 11.2 km (6 to 7 miles)
offshore in the Gulf, does not lend itself to the conventional
aeration reservoir. Mechanical aeration systems are considered
undesirable by this company due to the large quantities of
gaseous hydrogen sulfide that would be released to the atmosphere
and come in contact with personnel on the platform. Some
quantities of dissolved hydrogen sulfide are swept out of the
solution through gaseous evolution of carbon dioxide and methane
present in the formation water. Additionally, oxidation of
sulfides occurs through the reaction with the dissolved oxygen in
the seawater by using a diffuser system. The results of water
sampling, since the mine began operations, have shown an absence
of sulfides within 150 m (500 ft) of the discharge points.
Because conventional treatment systems (ponds) cannot be used and
because relocation is impossible, situations such as this will be
regulated in a separate subcategory.
272
-------
Presently* there is only one major waste stream at facility 2023.
However, there are 6 other discharge points from this facility
primarily for rainwater runoffs. This mine has three pumping
stations in the field for rain water runoffs which are newly
designated discharge points. In addition, there are 3 discharge
points installed to cover rainwater runoffs and the drips and
drains from the levee system around the power facility. This
levee system has been built to improve the housekeeping in the
power facility area. The bleedwater from the mine is aerated in
one of three small reservoirs, located in the field area, prior
to pumping to the main treatment reservoir which is about
10 hectares (25 acres) in size. Here the water is sprayed to
reduce hydrogen sulfide concentrations. It is then impounded for
3-4 days where further aeration occurs. Finally, it is mixed
with pumped-in seawater at a ratio of 20 to 1 in a 1830 meter
(6000-foot), man-made canal to oxidize any remaining sulfides to
sulfates prior to discharge. Power facility wastes are also
piped into the canal where temperatures are eguilibrated and
solids are settled. Oxidation is effecting sulfide removal in
this ditch rather than just dilution as evidenced by the avearage
reduction of sulfide from 107 mg/1 to less than 0.1 mg/1 before
and after mixing with the seawater. A spray system was chosen
for aeration in this facility due to the lack of suitable land
space for the construction of a large conventional reservoir.
Four discharge streams emanate from facility 2024. Discharges f1
and #3, the power facility discharges and mining water from
sealing wells, respectively, discharge into a river without
treatment. Discharge t2, the bleedwater, flows by gravity
through a ditch into a >b hectare (125 acre) reservoir where
oxidation of hydrogen sulfide is accomplished. The effluent
residence time in this reservoir is about 15 to 18 days. The
treated bleedwater flows into a swift flowing tributary of a
river just before it enters tidal waters. All sewage effluents
entering into discharge #4, which is primarily rain runoff, are
treated through a septic tank system prior to discharge.
At mine 2025 the bleedwater flows to a small settling basin from
where it is routed through a mixing zone. Sulfurous acid and
deposition inhibitor are added to the bleedwater in this mixing
zone and then the waste water is routed to packed towers for
hydrogen sulfide removal. In the packed towers, the bleedwater
flows counter current to cooled boiler flue gas. The treated
bleedwater is next aerated and sent to a 10 hectare (25 acre)
settling basin. The overflow from the settling basin flows
through two 10-12 hectare (25 to 30 acre) clarification ponds,
prior to discharge into the tidal section of a river through a 35
km (22 mile) long disposal canal. The effluents from the water
softening and treating operations are discharged into an earthen
pond to settle the solids and the sludge. The supernatant water
from this pond is discharged into a river. The solids are mixed
with some clay and used as substitute drilling mud. Rainfall
273
-------
runoffs, boiler blowdown and other facility area wastes are
discharged without treatment. The sanitary waste is treated in a
septic tank system and then discharged into oxidation ponds. The
overflows from these ponds are discharged into a river.
In mine 2026, the bleedwater is treated in a series of three
ponds for settling and oxidation. Pond #1 is about 1U hectares
(35 acres) and ponds f2 and #3 are about 52 hectares (130 acres)
each on size. The overflow from pond #1 flows through a 3.2 km
(2 mile) ditch into pond #2. The overflow from the third pond is
discharged into a river. Part of the rainfall runoff, a small
part of the, boiler blowdown (the continuous blowdown is returned
to the mine water system), zeolite softener regeneration water,
pump gland water, and washwater are sent into a nearby lake
without treatment. The blowdown from the hot process softening
system and clarifier system is discharged to pits where the
excess supernatant is discharged with the remaining rainfall
runoffs into the creek. The settled solids are used as drilling
mud. The sanitary waste of this mine is treated in a septic tank
system and reused in the mine water system.
At mine 2027 the bleedwater treatment process used consists of
contacting the waste water from the bleedwells with sulfurous
acid with provisions for adequate mixing followed with sufficient
retention time. Sulfurous acid is made both by burning liquid
sulfur or from hydrogen sulfide originating from the bleedwater.
In this process, the soluble sulfides in the bleedwater are
converted to elemental sulfur and oxidized sulfur products in a
series of reaction vessels. The excess acid is next neutralized
with lime and the insoluble sulfur is removed by sedimentation.
The effluent thus treated passes through five basins in series
having a total retention capacity of about one day. The overflow
from the last basin is discharged into a salt water canal which
flows into the tidal section of a river. The waste stream from
the water clarification operation is discharged into an earthen
pond to settle the solids and the sludge. The supernatant water
from this pond is mixed with boiler blowdown waste and other
waste streams prior to discharge into the salt water canal.
Rainfall runoffs are sent into the canal without any treatment.
The sanitary waste of this mine is treated in a septic tank
system and then discharged into a disposal field.
In mine 2028, the water from the bleedwells is sent into two
separate tanks from where it flows through 2tt km (15 miles) of
underground piping into a ditch about 5 km (3 miles) in length.
From there it flows into a 325 hectare (800 acres) pond for
oxidation and settling. Treated effluent from this pond is
discharged 60 days per year into a ditch. This is because the
canal water, while subject to tidal influence, is selectively
used for irrigation supply water. The waste stream from the
water clarifier and zeolite softening operation is discharged
into an earthen pond to settle the solids and the sludge. The
274
-------
supernatant water from this pond is intermittently pumped out
into a creek. The solids are mixed with some clay and used as
drilling mud. Boiler blowdown water, facility area wastes and
rainfall runoffs are sent into a nearby creek. The sanitary
waste of this mine is treated in a septic tank system and then
discharged in a disposal field.
The rainfall runoffs, boiler blowdowns, waste resulting from the
water softening and treating operations, facility area wastes are
sent into receiving waterways without any treatment. Therefore,
the composition of these streams are as given in the raw waste
load section. Table 14 compares the discharges from these
facilities. Alternate forms of sulfur treatment are discussed in
the following paragraphs.
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 trivalent
form with sulfur dioxide or bisulfites. Sulfides can be oxidized
with air to relatively innocuous sulfates. The oxidation
reactions for a number of sulfur compounds pertinent to the
sulfur industry are discussed below.
Inorganic Sulfur Compounds
Inorganic sulfur compounds range from the very harmful hydrogen
sulfide to the relatively innocuous sulfate salts such as sodium
sulfate. Intermediate oxidation products include sulfides,
thiosulfates, hydrosulfites, and sulfites. Oxidation of sulfur
compounds is accomplished with air, hydrogen peroxide, chlorine,
amoung others.
(1) Sulfides
Sulfides are readily oxidizable with air to thiosulfate.
Thiosulfates are less harmful than sulfides (of the order of 1000
to 1) .
2HS- + 20.2 ? S20J # + H20
The reaction goes to 90-95 percent completion.
(2) Thiosulfates
Thiosulfates are difficult to oxidize further with air (21).
They can be oxidized to sulfates with powerful oxidizing agents
such as chlorine or peroxides. However, the Frasch sulfur
industry has experienced oxidation of sulfides with air to
elemental sulfur and oxidation of thiosulfides to sulfates.
275
-------
TABLE 14
SULFUR FACILITIES
COMPARISON OF DISCHARGES
ro
Plant
Age
Location
Total Discharge, 106
I/day 3
Tctci Discharge 10
Vkkg
Bleeawater discharge,
106 I/day
Bleedwafer discharge,
TO3 1/kkg
Pollutants (in total
discharge)
TSS, mg/i
TSS, kg/kkg
Suifide, mg/ 1
Suifide, kg/kkg
TSS (seawater contribution
omitted) kg/kkg 4.8
2021
14
La*
74
180
4.6
11.2
57
10.3
16
2.9
2023
41
La*
428
260
27
16.4
33
8.6
0.4
0.1
2024
21
La
19
6.9
19
6.9
95
0.7
51
0.4
2025
45
Tx
38
12.1
38
12.1
30
0.4
nil
nil
2026
26
Tx
17
20
17
20
20
0.4
nil
nil
2027
22
Tx
23
20.5
23
20.5
5
0.1
nil
nil
2028
17
Tx
11.5
21.5
11.5
21.5
40
0.9
nil
nil
2029
28
Tx
8.7
11.8
8.7
11.8
50
0.6
not de-
tected
2097
6
Tx
11.5
22.1
11.5
22.1
30
0.7
2
0.04
0.3
0.7
0.4
0.4 0.1
0.9 0.6
0.7
* Bayou
-------
(3) Hydrosulfites
Hydrosulfit.es can also be oxidized by such oxidizing agents and
perhaps with catalyzed air oxidation.
Sulfites
Sulfites are readily oxidized with air to sulfates at a
90-99 percent completion level. Chlorine and peroxides are also
effective.
Salt dome sulfur producers have large quantities of bleedwater to
treat and dispose of. This presents two problems: removal of
sulfides and disposal of the remaining brine. Since there is
currently no practical or economical means of removing the salt
from the brine, it must be disposed of either in brackish or salt
water, or impounded and discharged intermittently during
specified times.
Removal of sulfides prior to discharge of the brine is also a
major treatment problem. There are two types of bleedwater
treatment facilities found in this industry for removal of
sulfides. Examples of each are given in Figure 58. ^
In treatment type 1 the bleedwater is air lifted to a small
settling basin and then sent to a mixing zone where sulfurous
acid and deposition inhibitor are added. The bleedwater is then
sent to packed towers for removal of hydrogen sulfide. In the
packed towers the bleedwater flows countercurrent to cooled
boiler flue gas. The treated bleedwater is then aerated and sent
to a series of settling and clarification ponds prior to
discharge. This method is effective for removal of sulfides in
the bleedwater.
In treatment type 2 the bleedwater is mixed with sulfurous acid
which is generated by burning liquid sulfur or from hydrogen
sulfide originating from the bleedwater. In this process the
soluble sulfides in the bleedwater are converted to elemental
sulfur and oxidized sulfur products in a series of reaction
vessels. Excess acid is then neutralized with lime. The
insoluble sulfur is removed by sedimentation, and the treated
effluent is then sent to a series of basins prior to discharge.
This method is very effective for removal of sulfides.
SULFUR (FRASCH - OFFSHORE)
At the one off-shore salt dome sulfur facility currently
operating, the bleedwater is discharged without treatment through
a diffuser system. The treatment technologies used by on-shore
salt dome facilities, ponding and bleedwater treatment facilities
are not considered feasible here due to non-availability of land
and space restrictions on a platform.
277
-------
FIGURE 58
SUUFUROUS
ACID
OPPOSITION
IKHI9ITOR
AIR LIFTED ^ SETTLING 1 T
BLEEOWATER " BASIN nxf* PIPE
RAW WATER »•
BCiLER
FLUE *»
GAS
FLUE GAS FLUE CAS
TO STACK TO STACK
1 t
PACKED PACKED
TC.YE33 Tokens
l Ik
ECONOMIZER
i
TO PROCESS
FOR >'",£ \VATER
., AERAT09S '. » SETTLING
» AERATORS — *• BA3iMS
WASTE WATER
DISCHARGE
BLEEDWXTER TREATING PLANT
TYPE I
WATER
LIQUID
SULFUR
BURNERS
BLEECWATER-t»
BLEEDWATER TREATING PLANT
TYPE 2
278
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PIGMENTS
In the wet processing of iron oxide pigments, water overflow from
the rake thickener drains to a large settling pond. It is then
recycled to the process with no further treatment. At facility
3022 the waste water is discharged to a 41 hectare (100 acres)
settling pond which is also used for effluent from a barite
operation. The discharge from the large pond is mainly
attributable to the barite operations.
LITHIUM
The treatment of the process waste stream consists of
flocculation and gravity settling. The slimes and flotation
tailings are primarily alkali aluminum silicates and quartz. A
flocculating agent is added and the slurry is pumped to settling
ponds, and the major part of the overflow is returned to the
facility for re-use. The mine water which is pumped
intermittently is both discharged and recycled to the process
water circuit. An additional waste stream which is unique to
facility 4009 arises from the scrubbing circuit of the low-iron
process which removes certain impurities from the spodumene
concentrate product. This stream is currently being impounded
for future treatment prior to being discharged.
For facility 4009 the point of measurement of the discharge
encompasses significant flow from two streams which pass through
the property and serve as an intake water source to the facility.
The significant dilution by stream water makes it impossible to
assess the effluent quality directly. Effluent data are as
follows:
Facility 4001 Facility 4009
Mine Mill Mine Mill
Flow I/day 0.57 7.9
mgd 0.15 2.088
pH 6.1-7.9 7.0-7.5
TSS, mg/1 14 41 256 336
667
10 13 14
14 15 18
25
Facility 4001 is currently constructing an impoundment and will
recycle all process waste water. Facility 4009 is essentially
achieving no discharge. Discharge does occur as seepage from the
tailings dam and as overflow from the tailings pond during heavy
rainfall.
279
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The mine water at mine 4001 was observed by the project officer
to be very muddy, possibly requiring use of flocculants.
BENTONITE
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. Mine dewatering was not found.
FIRE CLAY
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
3087
3300
3301
3302
3303
3307
33C8
3309
3310
3332
3333
3334
3335
3336
3337
3338
Treatment
Pond
Lime & Pond
lime, combined
with other
waste streams
None
None
None
None
None
Pond
Pond
None
None
None
None
None
None
None
None
PH
7.25
6.5
4.0
6.0-6.9
6.9
8.3
7.0
9.2
5.0
4.2
3.0
—
--
--
—
—
--
2.6-3.0
TSS
mg/1
3
26.4,62
45
4
2
30
1
5
16
16
30
10
45
27,144
37
15
253-392
Total
Fe
mg/1
20
80
—
--
--
—
—
—
530- 1
ATTAPULGITE
280
-------
Bearing cooling water at facility 3060 is discharged with no
treatment while water used in pugging and kiln cooling is
evaporated in the process. 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, and 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 micro-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.
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. Data of the mine dewatering discharges
follow.
Mine _pj TSS. mq/1
3058 6.8 17
3060 7.5 19
MONTMORILLONITE
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)J2), 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
can present a greater problem for montmorillonite producers than
for attapulgite producers, due to the very slow settling rate of
some of the suspended clay. Accumulated rain and ground water is
pumped to abandoned pits for settling to the extent possible and
is then discharged. At facility 3073 the pit water is used as
makeup for the scrubber water.
281
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Data on mine dewatering follows.
Mine pH TSS,mg/1
3059 4.5-5.5 200-400
3323 3.8-4.4 2 U.33 6.3 6.3
6.7 8 8 9 9.5
10.3 12.33 16 18
24 33 42 52
258
3324 6-9 25.7 26 30 37
53 137 436
3325 7-8 0.67 1.67 2 3
4.33 5.5 8 11
12 18 21.3 60
The high value of 258 mg/1 TSS at mine 3323 occurred during a 6.6
cm (2.6 in) rainfall. However, the mine was not being dewatered.
In June 1975, the representatives of a flocculant manufacturer
conducted a . study of the mine dewatering quality at plant 3059.
By use of a flocculant, TSS was reduced from 285 to 15 mg/1 and
turbidity from 580 to 11 JTU. The flocculant manufacturer's
representatives were confident that a full scale system would
also produce significant reduction of TSS. Flocculation tests
were also conducted at mine 3324. With a cationic
polyelectrolyte 50 mg/1 TSS was achieved. With supplemental alum
10 mg/1 TSS was achieved.
KAOLIN (DRY)
The solid waste generated is land-disposed on-site. There is no
process effluent discharged.
KAOLIN (WET)
The facilities treat the process waste water ponds with lime to
adjust pH and remove excess zinc which is used as a bleaching
agent. This treatment effects a 99.8X 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 unusually high
turbidities to decrease before resuming a discharge.
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.
282
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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 of the
best fitting distribution (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 <43
3025 24.5 83 62.5
3314 58.2 202
3315(1) 32.9 140 113.7
3315(2) 32.7 76.7
Long term TSS data was not available. What TSS values were
available were correlated with the corresponding turbidity values
as follows:
TSS, mg/1
Facility 50 JTU (NTU) 100 JTU (NTU)
3024 45 90
3025 35 70
3315 50 100
Two interesting items were noted in additional data collected at
the request of EFA at facility 3315. Approximately one-half of
the total suspended solids were of a volatile nature confirming
the company's concern that aquatic growth in part was
contributing to the suspended solids. This is expected, since
organic reagents are used in kaclin processing and the treatment
ponds are situated in swampy areas having an abundance of plant
growth. The second point is that only about one-half of the
turbidity was removed after waste water samples were filtered in
the determination of TSS. This indicated that the kaolin and
possibly the volatile solids are sub-micron in size and are not
necessarily measured by TSS alone.
KAOLIN (MINE DEWATEPING)
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.
283
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The following mine drainage concentrations were measured.
Mine TSS, mg/1 JTU
3074 10
3080 10
3081 10
3311 22
3312 7.4
3313 41
3316 95.2* 44.6*
3317 232*
3318 79.5*
*daily maximum achieved in 99 percent of samples
Mine 3316, 3317 and 3318 blunge the ore at the mine site and add
a dispersant such as sodium tripolyphosphate to the slurry to
facilitate pumping the ore to the process plant. It is this
dispersant that causes the relatively high values.
BALL CLAY
Mine pumpout is discharged either after settling in a pond or
sump or without any treatment. Data are as follows:
Mine TSSj mg/1
3326 0 23143
3327 48
3328 0 312
3329 0
3330 53
3331 15 200
5684 146
The extreme variability of the effluent guality is due to the
presence of colloidal clays, as observed by the project officer
after a substantial rainfall.
Scrubber water at these facilities is sent to settling ponds. La
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.
284
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The amounts of process wastes discharged by these facilities are
calculated to be:
facility
5684
5685
discharge,
1/kkg of product
(gal/ton)
88 (21)
1,080 (260)
TSS. kq/kkq
of product
(lb/1000 Ib)
0.0001
0.43
5689
834 (1,030)
0.17
TSS
mcr/1
400
2970
82
1016
1054
10046
49
107
4
TDS
mg/1
240
1047
236
511
433
3216
153
164
273
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.
FELDSPAR (FLOTATION)
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):
waste water into system
discharge from system
TSS
3,790
21
Fluoride
14
1.3
285
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The process water effluents after treatment at these
facilities have the following quality characteristics:
five
facility
3026
3054
3065
3067
3068
6.5-6.8
6.8
10.8*
7.5-8.0
7-8
TSS
mq/1
21
45
349
35
40-150
Fluoride
mq/1
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.
facility
3026
3054
3065
3067
3068
ore processed basis
flow. TSS.
1/kkg kg/kkg
(gal/tonl (lb/1000 Ifci
14,600
(3,500)
12r500
(3,000)
11,000
(2,640)
6,500
(1,560)
18,600
(4,460)
0.31
0.56
1.1
0.23
0.7-2.8
fluoride,
kg/kkg
(lb/1000 Ibi
0.12
0. 18
0.25
0.22
0.6
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. Facility 3026 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 to reduce fluoride by binding it into the
sediment. The effectiveness of the treatment at 3026 to reduce
suspended solids is comparable to that at facilities 3054 and
3067.
286
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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.
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 (NON-FLOTATION)
Waste water is spilled on the ground (Facility 3032) or is
evaporated during crushing and milling operations (Facility
3064). There is no waste water treatment at either facility,
since there is no discharge.
KYANITE
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 with no loss through
pond seepage.
There is normally no discharge of process water from facility
3015. The only time pond overflow has occurred 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 the 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.
MAGNESITE
The waste stream at the one magnesite facility is the underflow
of the tailings thickener which contains large quantities of
solid wastes. Make-up water is added to transport these wastes
to the tailings pond. The estimated area of this pond is 15
hectares (37 acres). The estimated evaporation at this area is
21 cm/yr (51 in/yr) and the annual rainfall is 2.4 cm/yr (6
in/yr). The waste water is lost about 40 percent by evaporation
and about 60 percent by percolation. No 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-offs, were visible.
287
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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.
SHALE AND COMMON CLAY
There is no waste water treatment necessary for shale and common
clay 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.
APLITE
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 619 mg/1
average, and 1000 mg/1 for any one day. Actual settling pond
water analyses have not been made. 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.
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.
TALC MINERALS
(LOG WASHING AND WET SCREENING)
The waste streams emanating from the washing operations are sent
to 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. There is no discharge from these properties.
TALC (MINE DEWATERING)
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 basins and seals for centrifugal
pumps which discharge this water to upper level sumps or to the
288
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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:
TSS
7.5-8.3 4, 9
2037
2038
2039
2040
2041
2012
2043
7.8
8.1
7.0-7.8
7.2-8.5
8.7
7.8
3
4
1, 3
15
28
9
7.6
I/day
(gal/day)
545,000
(144,000)
878,000
(232,00(5)
1,920,000
(507,000)
1,900,000
(507,000)
1,100,000
(300,000)
49,200
(13,000)
496,000
(131,000)
76,000
(20,000)
Disposition
Pumped to a
swamp
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
TALC (FLOTATION AND HMS)
At facility 2031, the 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 a 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 34,000,000 liters (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 is sent back to the mill
and the remainder is discharged to a brook near the property.
Iri 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,
289
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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
r>rim?.TT' «*«>»-tling pc^2 and is discharged! i. *ro 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 acre). 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, it has been estimated that the present settling pond
will be filled within two years' time. This company has leased a
new piece of property for the creation of a future pond.
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 ponds. The
significant constituents in these streams are reported to be as
follows:
Waste Material
Facility Number 2032 2033 2014
PH
TSS, mg/1
7.2-8.5
<20(26)*
5.6
80 (8)*
7.0
100
*Contractor verification
The average amounts of TSS discharged in these effluents were
calculated from the above data to be:
facility kg/kkg (lb/1000 lb>
product
2032 <0.34
2033 0.29
204U 0.50
GARNET
Facility 3037 recycles untreated pit water used in screening
operations, and sends water from jigging operations to a settling
pond before discharge. 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
290
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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 arising from flotation underflow at facility 3071 is
discharged- ^he pH is maintained at 7. The suspended solids
content averaged 25 mg/1.
DIATOMITE
All waste water generated in diatomite preparation at
facility 5500 is evaporated. There is no process water, cooling,
or mine pumpout discharge. 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. 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.
GRAPHITE
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 added 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.
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:
291
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facility
average
mq/1
Flow I/day
(gal/day)
total solids 750
TSS
Volatile
Solids
Mn
Total Fe
BOD
COD
PH
10
0.1
0.1
9
20
7.3-8.5
24 hr.
maximum
mq/1
1,160,000
(300,000)
1600
20
10
0.5
2
15
20
6.8
State Standards
monthly
average
mq/1
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 from the acid
mine drainage treatment more than that normally expected from a
well designed pond.
JADE
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 lawn where it
evaporates and/or seeps into the ground. Solid wastes in the
form of tailings which collect in settling tanks are eventually
land-disposed as fill.
NOVACULITE
Water from the scrubber is sent to a settling tank and clear
water is recycled to the scrubber, cooling water is discharged
onto the lawn with no treatment.
PRETREATMENT TECHNOLOGY
Most minerals operations have waste water containing only
suspended solids. Suspended solids is a compatible pollution
parameter for publicly-owned treatment works. However, most of
292
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these mining and processing operations are located in isolated
regions and have no access to these treatment facilities. No
instances of discharge to publicly-owned treatment facilities
were found in the industry. In the relatively few instances
where dissolved materials are a problem, pH control and some
reduction of hazardous constituents such as fluoride would be
required. Lime treatment is usually sufficient to accomplish
this. Sulfides would require air oxidation or other chemical
treatment,
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. Some impact on air quality occurs with
sulfide wastes generated in sulfur production. However, the
isolated locations of sulfur facilities and selection of
treatment is usually sufficient to eliminate any problem. There
is also radiation from phosphate ores and wastes. The
concentration of radionuclides is low in materials involved with
phosphate mining and beneficiating operations. "Nevertheless,
significant quantities of radionuclides may be stored or
redistributed, because of the large volumes of slimes tailings
and other solid wastes.
Large amounts of solid waste in the form of both solids and
sludges are formed as a result of suspended solids removal from
waste waters as well as chemical treatments for neutralization
and precipitation. 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. 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 40, Chapter 1; Part 241) may be used as guidance for
acceptable land disposal technigues.
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
293
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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. Since these
industries generally have sufficient space and earth-moving
capabilities, they manage it with greater ease than most other
industries.
For the best practicable control technology currently available
the added annual energy requirements are estimated to be 555
million kw-hours. Much of this added energy requirement is
attributed to wet processing of crushed stone, phosphate rock and
sulfur (on-shore salt dome).
29U
-------
SECTION VIII
COST, ENERGY, WASTE REDUCTION BENEFITS AND NON-WATER
ASPECTS OF TREATMENT AND CONTROL TECHNOLOGIES
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.
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. 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.
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
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.
295
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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.
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:
Uniform Annual Disbursement =P i (1+i)nth 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-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 the 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.
(4) 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.
296
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(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,i»70/hectare ($1,000/acre) .
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 equal the total costs for treatment and
disposal. 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.
All facility costs are estimated for representative facilities
rather than for any actual facility. Representative facilities
are defined to have a size 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. 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.
Costs are developed for various types and levels of technology:
Minimum (or basic level^. That level of technology which is
egualled 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) .
B,C,D,E Levels - 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 not included unless
otherwise specified.
(2) Water treatment, cooling tower and boiler blowdown discharges
are not included unless otherwise specified.
(3) The specific removal of dissolved solids is not included.
(U) Mine dewatering treatments and costs are generally considered
separately from process water treatment and costs. Mine
297
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dewaterinq 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.
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.
298
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INDIVIDUAL MINERAL WASTE WATER TREATMENT AND
DISPOSAL COSTS
DIMENSION STONE
Of the sixteen facilities inspected, thirteen use settling ponds
for removal of suspended solids from waste water, two had no
treatment and the other facility uses a raked settling tank.
Approximately one-third of these facilities have total recycle
after settling. Pond settling and recycle costs are given in
Table 15. Since pond cost is the major investment involved, cost
for settling without recycling is similar. There was no
discernible correlation between facility age and treatment
technology or costs. Facility sizes ranged from 2,720 to
64,100 kkg/yr (3,000 to 70,650 tons/yr). Since pond costs vary
significantly with size in the less than one acre category,
capital costs may be estimated to be directly proportional to the
0.8 exponential of size and directly proportional for operating
expenses. Waste water treatment cost details for the typical
facility values at Level C are shown below. Level B costs are
similar except for recycle eguipment.
Production: 18,000 kkg/yr (20,000 tons/yr)
8 hr/day; 250 days/yr
Water Use and Waste Characteristics:
4,170 1/kkg (1,000 gal/ton) of product
2% of product in effluent stream
5,000 mg/1 ?SS in raw effluent
360 kkg/yr (400 tons/yr) waste, dry basis
280 cu. m. (10,000 cu. ft.) wet sludge per year
1,300 kg solids per cu. m. sludge (80 Ib/cu. ft.)
Treatment: Recycle of wash water after passing through
a one acre settling pond
Cost Rational:
Pond cost $10,000/acre
Total pipe cost $1/inch diam/linear ft.
Total pump cost $100/HP
Power costs $0.02/kwh
Maintenance 5% of capital
Taxes and insurance 2% of capital
Capital recovery factor 0.1627
299
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TABLE 15
DNENSIQN STONE TROTENT COSTS
PLANT SIZE
187000
PLANT AGE 50 YEARS
KKG
PER YEAR OF Product
PLANT LOCATION "ear population center
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/ KKG product
WASTE LOAD PARAMETERS
(kg/ kkg of product )
Suspended Solids
• .
RAW
WASTE
LOAD
20
LEVEL
A
(MIN)
0
0
0
0
0
0
20
B
10,000
1,600
900
200
2,800
0.16
0.8
C
13,600
2,200
950
400
3,550
0.20
0
D
•
E
LEVEL DESCRIPTION:
A — direct discharge
B — settling, discharge
C — settling plus recycle
All costs are cumulative.
300
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CRUSHED STONE
DRY PROCESS
An estimated seventy percent of the crushed granite and limestone
facilities use no process water.
WET PROCESS
A typical wet crushed stone operation is assumed to produce
180,000 kkg/yr (200,000 tons/yr), half of which is washed, and
half is dry processed. The assumed wash water usage is
1,COO 1/kkg (2UO gal/ton), and the assumed waste content is 6% of
the raw material. The cost data are presented in Table 16.
Levels B and C involve simple settling, discharge, or recycle.
The waste water is passed through a one acre settling pond and
discharged or recycled back to the facility. The pond is dredged
periodically and the sludge is deposited on site.
Level D involves settling with flocculants and recycle. The
waste water is treated with a flocculant and passed through a one
acre settling pond. The effluent is then recycled. It is rare
that a flocculant would be needed to produce an effluent quality
acceptable for recycle in a crushed stone operation.
Level B
Pond Cost $10,000
Pumps and piping 4,500
Power 1,000
Pond cleaning 6,000
Taxes and insurance UOO
Level C
Total pond cost $10,000
Total pump and piping cost 9,000
Annual capital recovery 3,100
Power 2,000
Pond cleaning 6,000
Taxes and insurance 100
Level D
Additional capital flocculant equipment $ 3,500
Additional annual capital 600
Annual chemical cost 1,000
301
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TABLE 16
CRUSHED STONE (WET PROCESS) TRE/TOIT COSTS
PLANT SIZE 180,000
PLANT AGE 40 YEARS
KKG
PER YEAR OF Crushed Stone
PLANT LOCATION rural location near population center
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/ KKG product
WASTE LOAD PARAMETERS
(kg/ kkg of product )
Suspended Solids
RAW
WASTE
LOAD
60
.
LEVEL
A
(WIN)
0
0
0
0
0
0
60
B
14,500
2,400
6,400
'1 ,000
9,800
0.054
0.2
C
19,000
3,100
6,400
2,000
11,500
0.064
0
D
22,500
3,700
7,400
2,000
13,100
0.073
0
E
LEVEL DESCRIPTION:
A — direct discharge
B — settling pond, discharge
C — settling pond, recycle
D — flocculant, settling pond, recycle
All costs are cumulative.
302
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Granite fines settle somewhat slower than limestone fines. As a
result, recirculation granite ponds generally run about 50%
larger than those of limestone for the same capacity facility.
The amount of waste in the effluent is largely dependent on the
type of product. Six percent waste solids was chosen as an
average value. The range of wastes is 2 to 12 percent. The cost
to treat per ton of product is approximately proportional to
percent waste. The amount of stone washed in any given year
varies with the demand for a washed product. The capital costs
for treatment are more readily absorbed when a large portion of
the stone is washed. Capital costs are estimated to be directly
proportional to the 0.9 power of size and operating expenses are
proportional to size.
There are an estimated 1600 facilities in this category
producting an estimated 140 million kkg (150 million tons) of
washed stone along with 140 million kkg (150 million tons) of dry
processed stone annually. An estimated 500 of these 1600
facilities are presently on complete recycle. The remaining 1100
facilities produce approximately 91 million kkg/yr (100 million
tons/yr) of stone, 50% of which is washed. The average cost
increase per ton for the wet process crushed stone industry would
be $0.048/kkg ($0.044/ton) to convert to recycle. The capital
expenditure for the same is estimated to be $10,000,000.
FLOTATION PPOCESS
There are an estimated eight facilities in this subcategory, with
a combined estimated annual production of 450,000 kkg (500,000
tons). The process is identical to that of wet crushed stone,
except for an additional flotation step, using an additional 5%
of process water. The wash water can be recycled as in wet
processing, but the flotation water cannot be directly recycled
due to the complex chemical processes involved. The two waste
streams can be combined; however, and be recycled in the washing
process. The flotation process would require fresh input. The
treatment used is settling ponds and recycle. Assuming a 5% loss
(equivalent to the input from flotation) from the combined
effects of percolation and evaporation, discharge would be
eliminated under normal conditions. It is estimated that two of
the eight facilities in this sufccategory are presently recycling
their wast^e water. The remaining six could achieve recycle with
total capital cost of $200,000.
303
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CONSTRUCTION SAND AND GRAVEL
DRY PROCESS
A typical dry process sand and gravel facility produces
450,000 kkg/yr (500,000 tons/yr) of construction sand and gravel.
There is no process water use, no non-contact cooling water and
usually no pit pumpout. Since there is no water use or waste
water generated, treatment is not required. Pit pumpout is
required at some facilities during periods of high rainfall.
Some facilities also have a non-contact cooling water discharge.
The pit pumpout in some of these cases is settled in a sump or
pond. Age, location, and production have no consistent effect on
waste waters from facilities in this subcategory, or on costs to
treat them. There are an estimated 750 facilities in this
subcategory representing a production of 129 x 106 kkg/yr
(143 x 1C6 tons/yr) .
WET PROCESS
The average production rate of facilities in this subcategory is
130,000 kkg/yr (143,000 tons/yr). Median facility size is
approximately ^27,000 kkg/yr (250,000 tons/yr). This is selected
as representative for facility size. The assumptions used in
costing are that: 10 percent of raw material is in the waste
stream (68,000 mg/1), 11,400 1/min (3,000 gal/min) is used for
washing, and all particles down to 200 mesh (74 micron) are
recovered for sale by screw classifier cyclones, etc. The costs
are listed in Table 17.
Level B: 5.6 acre settling pond and discharge of effluent.
Pond cost $28,000
Pump cost 2,000
Pipe cost 3,000
Annual power 300
Taxes and insurance 800
Maintenance 800
Level C: 5.6 acre settling pond followed by recycle of waste
water.
Total pond cost $28,000
Total pump cost 3,000
Total pipe cost 6,000
Power 600
Taxes and insurance 1,000
Maintenance 1,000
304
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TABL£17
CONSTRUCTION SAND AND GRAVEL (WET PROCESS)
TREATMT COSTS
PLANT SIZE 227,000
PUNT AGE 5 YEARS
KKG
PER YEAR OF product
PLANT LOCATION near population center
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/ KKO product
WASTE LOAD PARAMETERS
(kg/ biro of product )
-"*
Suspended Solids
RAW
WASTE
LOAD
TOO
LEVEL
A
(WIN)
0
0
0
0
C
0
TOO
B
33,000
5,400
1,600
300
7,300
0.03
0.4
C
37,000
6,000
2,000
600
8,600
0.04
0
D
40,000
5,200
21,000
600
26,800
0.12
0
E
50,000
8,100
29,200
400
37,700
0.17
0
F
180,000
29,200
41,400
600
71,200
0.31
0
•
G
21,600
2,600
28,100
400
31,100
0.14
0
LEVEL DESCRIPTION:
All costs are cumulative,
A — direct dischorge
B — settling, dischorge
C — settling, recycle
D — two silt removal ponds, settling pond, recycle
E — flocculont, mechanical thickener and recycle. Transportation of sludge to disposal basin.
F ~ flocculant, inclined plate settlers, and recycle effluent. Transport sludge to disposal basin.
G— flocculant, settling basin, recycle
305
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Level D: Two silt removal ponds of O.OU ha (0.1 acre) each are
used alternately prior to the main settling pond of 5.6 acres.
The life of the main pond is greatly increased as most of the
solids are removed in the primary ponds. One small pond is
dredged while the other is in use. The sludge is deposited on
site.
Total pond cost $30,000
Annual pond cost 3,600
Total pump and piping 10,000
Annual pump and piping 1,600
Annual dredging and
sludge disposal 20,000
Power 600
Taxes and insurance 1,000
Level E: A mechanical thickener is used along with a
flocculating agent to produce an effluent of 250 mg/1 for
recycle. The underflow sludge is transported to a 1 acre sludge
disposal basin at a cost of $1.1/kkg ($l/ton)
Total thickener cost $ 18,500
Sludge disposal basin cost 20,000
Polymer feed system cost 1,600
Pump and piping 9,700
Annual sludge transportation 25,000
Annual chemical cost 2,200
Annual power 400
Maintenance 1,000
Taxes and insurance 1,000
Level _F: Inclined plate settlers are used to produce an effluent
of 250 mg/1 which is recycled back to the process. A coagulant
is added prior to the settlers to increase settling rate. The
underflow sludge is transported to a •* acre settling basin at a
cost of one dollar per ton of solids. It should be noted that no
case of an inclined plate settler successfully treating a sand
and gravel waste was found. The advantage of this system is the
small area required.
Inclined plate settler cost $150,000
Pumping and piping 10,000
Sludge disposal basin 20,000
Sludge transportation 25,000
Chemical 2,000
Maintenance 7,200
Taxes and insurance 7,200
Power 600
306
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Level G: Flocculant added, 1 acre settling pond is used for
treatment, and effluent is recycled to the process. The sludge
is dredged and deposited on site at a cost of $0.55/kkg
($0.50/ton).
Total pond cost $ 10,000
Polymer mixing unit 1,600
Pump and piping 10,000
Chemical cost 2,200
Dredging 25,000
Power 400
Taxes and insurance 900
The production rate in this subcategory varies from 10,900 to
1,800,00 kkg/yr (12,000 to 2,000,000 tons/yr). The waste volume
and water flow vary proportionately with production. As a
result, the necessary settling area varies proportionately with
production. The necessary pond capacity also varies
proportionately with sludge volume, and thus production.
Pumping, piping and power costs may also be considered to be
roughly proportional to water flow, and production. Thus, the
capital costs for Levels B, C, D, and G are estimated to be
directly proportional to the 0.9 power of size. Operating costs
not related to capital are approximately directly proportional to
size. Levels E and F use eguipment for clarification rather than
ponds. Capital costs for them should be directly proportional to
the power of 0.7 to size. Operating costs not based on
capitalization are approximately directly proportional to size.
A facility having a waste content other than ten percent should
reguire a proportionately different water usage. The settling
area required to obtain recyclable effluent should be
proportional to waste content. Dredging and pumping are also
proportional to waste content. Thus the treatment cost per ton
of product should vary roughly proportionately with waste
content. Waste content can vary from less than 5% to 30%.
A canyon or hillside can greatly reduce the cost of pond
building. Also, a wet land can increase the cost of building a
pond.
A suspended solids average particle size greater than the one
shown would mean a proportionately smaller settling area would be
need to produce recyclable effluent. A smaller particle size
could be countered with the use of a flocculant, if necessary.
An increase in settling rate would require a proportionately
smaller settling area. A settling rate increase due to the use
of coagulant of 100 times was assumed, based on laboratory tests
and industry supplied information.
307
-------
There are an estimated 4,250 facilities in the wet processing
subcategory, producing 519 million kkg/yr (573 million tons/yr).
Of these, an estimated 50% (2,125 facilities) are presently recy-
cling their effluent. Another estimated 25% (1,063 facilities)
have no discharge under normal conditions due to evaporation
and/or percolation in settling ponds. The remaining 25%
(1,063 facilities) presently have a discharge. It is estimated
that 90% of the facilities having a discharge (956 facilities)
presently have a ponding system. These latter facilities could
in most cases convert their ponds to a recycle system by
installing pumps and pipe, with the use in some cases of a
coagulant.
Thus the facilities in this sutcategory without present ponding
systems are estimated to be 2.5% (107 facilities). Almost all of
these facilities could install treatment options C, D, or G,
which are the least expensive. Options E or F would only be
reguired in an urban environment where sufficient settling area
is not available on site.
The 956 facilities with settling pond discharges produce an
estimated 152 million kkg/yr (168 million tons/yr). The
installation of a pump and piping system, and the addition of a
flocculant would result in a total annual cost per ton of
$0.02/kkg ($0.018/ton), or the total capital expenditure reguired
represents about 7.4 million dollars.
The 107 facilities which are presently discharging without
treatment produce an estimated 16 million kkg/yr (18 million
tons/yr). The facilities not having any ponds could achieve
recycle for a capital cost of 1.7 million dollars. It is assumed
that these facilities may achieve recycle for an average
annualized cost of $0.11/kkg ($0.10/ton). It should be noted
that a small fraction of these 107 facilities have no land for
settling ponds, and that no sand and gravel facility utilizing
options E or F (no ponds) to achieve recycle was found.
The entire subcategory of wet processed sand and gravel could
eliminate discharge of process effluent for a total capital
expense of about 10 million dollars. The average cost of
production would rise $0.019/kkg ($0.017/ton).
RIVEP DREDGING, ON-LAND PROCESS
A production of 360,000 kkg/yr (400,000 tons/yr) was assumed.
The same treatment options apply as in wet process facility.
Costs of waste water treatment for the typical facility can be
derived from these presented in Table 17 by applying the
appropriate size factors. Factors affect treatment and costs in
the same manner as described for wet processing.
308
-------
There are an estimated fifty river dredging operations with on-
land processing, producing 13,300,000 kkg/yr (16,700,000 tons/yr)
of sand and gravel. An estimated 50% of the facilities producing
50% of the volume have no point source discharge at this time.
It is estimated that twenty-two of the remaining twenty-five
facilities have settling ponds at the present time. Recycle
should be achievable with the aid of a flocculant for an
increased production cost of $0.02/kkg ($0.018/ton). The total
capital cost for the subcategory is estimated to be $1,500,000.
The average increase in production costs would be $0.011/kkg
($0.01/ton).
309
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INDUSTRIAL SAND
DRY PROCESSING
Approximately 10 percent of the industrial sand operations fall
into this subcategory. The only water involved comes from dust
collectors used by some facilities. Of the five dry process
facilities surveyed, two have such scrubbers - one without
treatment and the other with pond settling and complete recycle.
Treatment is by addition of 5 mg/1 flocculating agent and recycle
through a one acre settling pond.
Assumptions:
167,000 I/day (44,000 GPD) scrubber water
5 days/week; 8 hours/day
flocculant cost - $1/lb
piping cost - $1/inch diam/linear foot
pump cost - $1/HP/yr
power cost - $.02/kwh
pond cost - $10,000/acre
TSS in raw waste - 30,000 mg/1
pond cleaning - $0.5/ton of sludge
Capital Costs:
pond $10,000
piping and pump 3,000
polymer mixing unit 1,500
total capital 14,500
annual capital
recovery 2,360
Operating Costs:
pond cleaning $ 700
power 150
chemical 50
maintenance 725
taxes and insurance 290
total annual operating 1,700
total annual recycle
costs $4,000
WET PROCESS
The wet process uses washing and screening operations are similar
to those for construction sand and gravel. Treatment of the
waste water is also the same. By use of ponds, thickeners and
clarifiers, three out of the four wet process facilities studied
310
-------
have no discharge of process water. Table 18 summarizes the
costs for two treatment technologies.
Level_A: 39 acre settling pond, discharge effluent
pond cost $60,000
pump cost 3,000
piping cost 6,000
Level B
Capital Costs
settling pond area 39 acres
pond cost $60,000
pump costs 6,000
piping costs 13,500
total capital $79,500
Annual Investment Costs
pond costs (20 yr life 3 10JK interest) = $7000
pump costs (5 yr life a 10ft interest) = 1500
piping costs (10 yr life 9105S interest) = 2200
total $10,700
Operating Costs
maintenance costs 3 2% of capital = $1600
power cost 9 $.02 per kwh = 2000
taxes and insurance cb 2% of
capital = 1600
total $5200
Leyel^C
Capital Costs
settling pond area - 39 acres
pond costs - $60,000
polymer feed system - 5,000
thickener - 60,000
pump costs - 15,000
piping costs - 15,000
total $155,000
total annual capital costs (10 years 3 10%) = $25,200
311
-------
TABLJE18
INDUSTRIAL SAND (WET PROCESS) TREATOT COSTS
PLANT SIZE 180,000
PLANT AGE 10 YEARS
KKG
PER YEAR OF product
PLANT LOCATION near population center
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/ KKG product
WASTE LOAD PARAMETERS
(kg/ WCT of product )
Suspended Solids
f
RAW
WASTE
LOAD
35
LEVEL.
A
(MIN)
69,000
8,000
2,800
1,000
11,800
0.07
0.7
B
79,500
10,700
3,200
2,000
15,900
0.09
0
C
155,000
25,200
21,900
2,000
49,100
0.26
0
D
E
LEV/EL DESCRIPTION:
All costs are cumulative.
A — settle,discharge
B — settle, recycle
C — mechanical thickener with coagulant, overflow is recycled to process. Underflow
is passed through a settling basin. Effluent from the settling basin is also recycled
to process.
312
-------
Operating Costs
chemicals $11,000
maintenance a 5%
of capital 7,800
power 2,000
taxes and insurance
9 2% of capital 3,100
total $23,900
The facilities surveyed for this sufccategory have ages from one
to 20 years. There is no discernable correlation of treatment
costs with facility age. Production capacities range from 54,000
to 900,000 kkg/yr (60,000 to 1,000,000 tons/yr). Treatment
technology Levels ft and B, involving pond costs, should show
slight unit cost variation (0.9 power). Level C technology with
a mechanical thickener as well as a pond are estimated to be
directly proportional to the 0.7 exponent of size. Operating
costs other than taxes, insurance and annualized capital costs
are estimated to be directly proportional to size.
ACID AND ALKALINE FLOTATION
There are three types of flotation processes used for removing
impurities from industrial sands:
(1) Acid flotation to effect removal of iron oxide and ilmenite
impurities,
(2) Alkaline flotation to remove aluminate bearing materials, and
(3) Hydrofluoric acid flotation for removal of feldspar.
These three flotation processes have been subdivided into two
subcategories; (1) acid and alkaline flotation and
(2) hydrofluoric acid flotation. Sufccategory (1) is discussed in
this subsection and subcategory (2) in the following subsection.
Four surveyed acid flotation facilities have no effluent
discharge. One alkaline flotation facility has effluent waste
water similar in composition to the intake stream. Recycle costs
for acid and alkaline flotation waste water are given in Table
19.
Cost Basis For Table 19:
(1) production - 180,000 kkg/yr (200,000 tons/yr)
(2) the process waste water is treated with lime, pumped to a
holding pond and recirculated back to the facility. The
holding pond is one-half acre and is cleaned once every ten
years.
313
-------
TABLE 19
INDUSTRIAL SAND (ACID AND ALKALINE PROCESS)
TREATMENT COSTS
PLANT SIZE 180,000
PLANT AGE 30 YEARS
KKG
PER YEAR.OF product
PLANT LOCATION southeastern U.S.
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/ KKG product
WASTE LOAD PARAMETERS
(kg/ kk§ of product )
Suspended Solids •
•
RAW
WASTE
LOAD
100
LEVEL
A
(MIN)
115,000
1 8,700
19,000
1,000
38,700
0.22
0.4
B
135,000
22,000
21,200
2,000
45,200
0.25
0
C
-
D
•
E
LEVEL DESCRIPTION:
A — neutralize, settle, discharge
B — neutralize, settle, recycle
All costs are cumulative,
314
-------
Capital Costs
lime storage and feed system - $75,000
reaction tank - U0,000
pumps and piping - 20^000
Total $ 135,000
annualized capital cost (10 yr life a 10%) $22,000
Operating Costs
chemical costs - $11,000
maintenance a 5% of capital - 7,300
power - 2,000
taxes and insurance a 2%
of capital - 2,900
total $23,200
Surveyed facilities in this subcategory ranged in age from one to
60 years. There was no discernable correlation between treatment
costs and facility age.
Facilities in this subcategory range between 19,000 to
1,360,000 kkg/yr (54,000 to 1,500,000 tons/yr). Costs/acre of
small ponds change significantly with size. Also, the chemical
treatment facilities costs are estimated to be directly
proportional to the 0.6 power of size. Taken together, capital
costs are estimated to be directly proportional to the 0,7
exponent of size. Operating costs, except for taxes, insurance
and other capital related factors may be expected to be directly
proportional to size.
HF FLOTATION
Unlike the acid and alkaline flotation processes where total
recycle is either presently utilized or believed to be feasible,
waste water from the HF flotation process is of guestionable
quality for total recycle. Estimated costs for partial recycle
are given in Table 20. Only one such facility is known.
Cost Basis For Tatle 20:
(1) production: 180,000 kkg/yr (200,000 tons/yr)
(2) all waste waters are fed to a thickener to remove suspended
materials. The overflow containing 90 percent of the water is
recycled to the process, the underflow is fed to a settling pond
for removal of solid wastes and pH adjustment prior to discharge.
315
-------
TABLE 20
INDUSTRIAL SAND OF FLOTATION) TREATMENT COSTS
PLANT SIZE 180,000
PLANT AGE - YEARS
KKG
PLANT LOCATION
PER YEAR .OF product
•
California
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/ YYQ product
WASTE LOAD PARAMETERS
(kg/ kkS of product )
Suspended Solids
Fluoride
RAW
WASTE
LOAD
135
0.45
LEVEL
A
(MIN)
120,000
19,500
21,400
2,000
42,900
0.23
0.044
0.005
•
B
200,000
32,500
21,400
2,000
55,900
0.31
0
0
C
-
* *
D
•
E
LEVEL DESCRIPTION: .
A — 90% of wastewater removed in thickener and recycled to process. Underflow from
thickener fed to settling pond for removal of tailings and pH adjustment prior to
discharge.
B — segregate HF waste water, pond and evaporate; recycle other water after ponding.
All costs are cumulative.
316
-------
Capital Costs
pond - 1/2 acre x 10 ft depth 3 $20,000/acre = $ 10,000
lime storage and feed system = 30,000
thickener = 60,000
pump costs = 5,000
piping costs = 15,000
total $120,000
annualized investment costs (10 yr life a 10% interest)
$120,000 x .1629 = $19,500
Operating Costs
maintenance 9 5% of capital
chemicals, lime 9 $20/ton
power 3 $.0 2/kwh
taxes and insurance a 2%
of capital
total
$6,000
11,000
2,000
2,400
$23,400
317
-------
GYPSUM
Gypsum is mined at sixty-five sites in the United States. An
estimated 57 of these facilities use no contact water in their
process. Two known facilities use heavy media separation and
washing to beneficiate the crude gypsum ore, which results in a
process effluent.
DRY PROCESS
There is no contact process water in this category, thus there
are no waste water treatment costs.
WET SCRUBBERS
Since the contractor's study, no plant in this subcategory
discharges process waste water.
HEAVY MEDIA SEPARATION
Both facilities presently recycle process waste water after
settling pond treatment. In one of the facilities an abandoned
mine is utilized as the settling pond. Capital investment for
the system is estimated to be $15,000. Annual operating cost is
estimated to be $10,000. Total annualized recycle costs are
estimated to be $12,500. This results in a recycle cost of
$0.05/kkg of gypsum produced ($0.0457ton).
MINE DRAINAGE
In all of the subcategories some facilities find it necessary to
pump out their guarries because of rainwater collection. No
facility is presently treating its mine pumpout water other than
what clarification occurs in a sump, and the average effluents
are all below 25 mg/1. Insofar as it is known there is no cost
to treat the pit pumpout.
318
-------
ASPHALTIC MINERALS
Of the asphaltic minerals, bituminous limestone, oil-impregnated
diatomite and gilsonite, only gilsonite operations currently have
any discharge to surface water. For gilsonite, present mine
water drainage treatment consists of pond settling of suspended
solids prior to discharge. Process water is discharged
untreated. Costs for present treatment are an estimated
$0.08/kkg of gilsonite produced ($0.07/ton). Completion of
treatment facilities currently under construction will result in
no discharge of waste water from the property at a cost of
$1. 10/kkg ($1/ton) of gilsonite produced. The cost estimates are
given in Table 21. The only gilsonite facility is located in
Utah. All costs are specific for this facility.
Level A
Capital Costs
pond cost, S/hectare ($/acre): 24,700 (10,000)
settling pond area, hectares (acres): 0.8 (2)
pump, piping, ditching: $5,000
Operating andMaintenance Costs
taken as 2% of capital costs
Level B
Capital Costs
pond costs - same as Level A
sand filters - $150,000
pumps and piping - 40,000
electrical and
instrumentation 25,000
roads, fences, landscaping - 15,000
Operating and Maintenance Costs
labor - 1/2 man a $10,000/yr $ 5,000
maintenance labor and materials
9 H% of investment 10,000
power 3 $.01/kw-hr 500
taxes and insurance
3 2% of investment 5,000
319
-------
TABL£21
GILSONITE TREATOT COSTS
PLANT SIZE 45,450
PLANT AGE 50 YEARS
KKG
PLANT LOCATION
PER YEAR OF Gilsonite
Utah
INVESTED CAPITAL COSTS'.. '$
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 G M (EXCLUDING
POWER AND ENERGY)
AN,', 'UAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG Gilsonite
WASTE LOAD PARAMETERS
Mine Pumpout:
Suspended Solids,mg/liter
BOD, mg/liter
Process Wafer:
Suspended Solids, mg/Iitei
BOD, mg/liter
RA\V
WASTE
LOAD
LEVEL
A
(MIN)
25,000
2,940
500
200
3,640
0.08
3,375
12
17
43
B
250,000
29,400
20,000
500
49,900
1.10
0
0
0
0
c
-
D
E
•
DESCRIPTION:
A — pond settling of suspended solids in mine pumpout; no treatment of process water
(present minimum).
B — combining of mine pumpour and process water followed by pond settling, filtration
and partial recycle. Discharge from recycle to be used. for on-property irrigation.
320
-------
ASBESTOS AND WOLLASTONITE
Asbestos is mined and processed at five locations in the U.S.,
two in California, and one each in Vermont, Arizona and North
Carolina. One facility in California uses wet processing while
the remaining four facilities use a dry process. There is also
one wollastonite dry facility which has no process water. The
wet process facility discharges twenty percent of the process
water 155,200 I/day (41,000 gal/day) to two
percolation/evaporation ponds. The ponds total less than one
half acre in size. The total capital investment for the
percolation ponds was estimated to be $2,000. Annual operating
and maintenance is estimated to be $1,000. The total annualized
cost is estimated to be $1,325 for the percolation/evaporation
ponds. One pond serves as an overflow for the other, therefore,
surface water discharge almost never occurs. The ponds are
dredged once annually.
Sixty-eight percent of the water in the wet process facility is
recycled via a three acre settling pond. A natural depression is
utilized for the pond, and dredging has not been necessary. The
water recirculated amounts to 529,900 I/day (140,000 gal/day).
Annualized cost for the recirculation system is estimated to be
$2,500. The remaining twelve percent of the process water is
retained in the product and tailings. Total annualized water
treatment costs for wet processing of asbestos are estimated to
be $3,825, which results in a cost of $0.09/kkg of asbestos
produced ($0.08/ton).
All five operations Accumulate waste asbestos tailings at both
facility and the mining site. These tailings are subject to
rainwater runoff. At two sites dams have been built to collect
rainwater and create evaporation/percolation ponds. The total
capital investment at each site is estimated to be $500,
Operating and maintenance costs for these dams are considered to
be negligible. Natural canyons were utilized in both cases to
create the ponds. One facility because of its geological
location must discharge water collected in its mine. The
alkaline grcundwater in the area requires the water to be treated
by addition of 0.02 mg/1 sulfuric acid before discharge. The
pumping costs for this operation are considered to be part of the
production process. The chemical costs are less than $100/yr.
The estimated capital cost for total impoundment of mine water to
eliminate the discharge is $15,000.
321
-------
LIGHTWEIGHT AGGREGATE MINERALS
PERLITE
All U.S. perlite facilities are in southwestern U.S. and the
processes are all dry. Since there is no water used, there is no
waste water generated, or water treatment required. One
investigated mine does dewater the quarry when water accumulates,
but this water is evaporated on land at estimated cost of $0.01
to $0.05/kkg (or ton) of perlite produced.
PUMICE
At most facilities, there are no waterborne wastes as no water is
employed. At one facility there is scrubber water from a dust
control installation. The scrubber water is sent to a settling
pond prior to discharge. Because of the relatively small amount
of water involved and the large production volume of pumice per
day, treatment costs for this one facility are roughly estimated
as less than $0.05/kkg (or ton) of pumice produced at that
facility.
VERMICULITE
Two facilities represent almost all of the total U.S. production.
Both of these facilities currently achieve no discharge of
pollutants ty means of recycle, pond evaporation and percolation.
Detailed costs for a typical facility are given in Table 22. The
ages of the two facilities are 18 and UO years. Age is not a
cost variance factor. One facility is located in Montana and the
other in South Carolina. In spite of their different
geographical location, both are able to achieve no discharge of
pollutants by the same general means and at roughly equivalent
costs. Facility sizes range from 109,000 to 209,000 kkg/yr
(120,000 to 230,000 tons/yr). Since pond costs per acre are
virtually constant in the size range involved, waste water
treatment costs may be considered directly proportional to
facility size and therefore invariant on a cost/ton of product
basis. Capital and operating costs were taken from industry
reported values. The basis of these values is shown as follows:
Assumptions:
Production:
Process Water Use:
Treatment:
Capital Cost:
Operating Costs:
Annual Capital
Recovery:
157,000 kkg/yr (175,000 tons/yr)
8,350 1/kkg (2,000 gal/ton)
settling ponds and recycle of
process water
$325,000
$ 45,000/yr
$ 52,900
322
-------
TABLE 22
VERMICULITt TREATrBTT COSTS
PLANT SIZE
160,000
KKG
PER YEAR OF product
PLANT AGE 30 YEARS
PLANT LOCATION Montana or South Carolina
INVESTED CAPITAL CQSTS:. $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 8. M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POV/ER
TOTAL ANNUAL COSTS
9
COST/ KKG product
WASTE LOAD PARAMETERS
(kg/ vvi» of product )
"
Suspended Solids
RAW
WASTE
LOAD
1,600
LEVEL
A
(WIN)
325,000
52,900
40,000
5,000
97,900
0.62
0
B
•
C
•
D
.
E
LEVEL DESCRIPTION:,
A — recycle, evaporation and percolation.
All costs are cumulative.
323
-------
MICA
There are seven significant wet mica beneficiation facilities in
the U.S., seven dry grinding facilities processing beneficiated
mica, and three wet grinding facilities. There are also several
western U.S. operations using dry surface mining. They have some
mine water drainage. Treatment for this mine water is estimated
as $0. 19/kkg ($0.2/ton) (based on a 1/2 acre pond 3> $10,000/acre
and operating costs of $750/yr).
WET BENEFICIATION PLANTS
Eastern U.S. beneficiation facilities start with matrices of
approximately 10 percent mica and 90 percent clay, sand, and
feldspar combinations. Much of the non-mica material is
converted to saleable products, but there is still a heavy
portion which must be stockpiled or collected in pond bottoms.
The variable nature of the ore, or matrix, leads to several
significant treatment/cost considerations. Treatment costs and
effluent quality differ from facility to facility. Additional
saleable products reduce the cost impact of the overall treatment
systems developed. Solids disposal costs are often a major
portion of the overall treatment costs, particularly if they have
to be hauled off the property.
All of these factors can change the overall treatment costs per
unit of product of Table 23 by at least a factor of two in either
direction. The known ages for four of the seven facilities range
from 18 to 37 years. There is no significant treatment cost
variance due to this range. The sizes range from 13,600 to
34,500 kkg/yr (1,500 to 3,800 tons/yr). The unit costs given are
meant to be representative over this size range on a unit
production basis.
Treatment Level A - Pond settling of process wastes (minimum
treatment)
(1) Production rate - 16,400 kkg/yr (18,000 ton/yr)
(2) Solid wastes ponded - 34,200 kkg/yr (38,000 ton/yr)
(3) Solid waste stockpiled - 45,000 kkg/yr (50,000 ton/yr)
(4) Pond size - 4 hectares (10 acres)
(5) Effluent quality
(a) suspended solids - 20-50 mg/1
(b) pH - 6-9
(6) Waste water effluent - 5.7 x 10* I/day (1.5 mgd)
324
-------
TABLE 23
MICA TREATMENT COSTS
PLANT SIZE 16,360
PLANT AGE 27 YEARS
KKG
PLANT LOCATION
PER YEAR.OF Mica
South eastern 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 ft
y
COST/ KKG Mica
WASTE LOAD PARAMETERS
(kg/ kkg of Mica )
Suspended Solids
pH
RAW
WASTE
LOAD
2,100
—
LEVEL
A
(WIN)
150,000
17,600
50,000
2,000
69,600
4.3
2.5-6
6-9
B
275,000
32,300
64,500
3,000
99,800
6.1
1.2-2.5
6-9
C
300,000
35,200
68,000
5,000
108,200
6.6
0
-
D
245,000
39,900
74,400
5,000
119,300
7.3
1.2-2.5
6-9
E
245,000
39,900
74,400
5,000
119,300
7.3
0
-
LEVEL DESCRIPTION:
All costs are cumulative
A — minimum level ponding
B — extended ponding and chemical treatment
C — closed cycle pond system (no discharge)
D — mechanical thickener and filter
E — closed cycle thickener and filter-system (no discharge)
325
-------
Capital Costs
Ponds = $100,000
Pumps and piping = 35,000
Miscellaneous constructions = 15,000
Total = $150,000
Assume 20 yr life and 10% interest
capital recovery factor = .1171
Annual investment costs = $17,610/yr
Operating Costs
Solid wastes handling a $0.30/ton = $15,000
Pond cleaning 3 $0.50/ton = 19,000
Maintenance = 10,000
Power = 2,000
Labor = 3,000
Taxes and insurance 3 2% of
capital = 3,000
Total $52,000
Treatment Level B - Pond settling of process wastes and
chemical treatment
The basis is the same as for Level A, except
(1) Pond size - 8 hectares (20 acres)
(2) Chemical treatments - lime, acid and
flocculating agents used as needed
(3) Effluent quality
(a) suspended solids - 10-20 mg/1
(b) pH - 6-9
Capital Costs
Ponds = $200,000
Pumps and piping = 50,000
Miscellaneous construction = 25,000
Total $275,000
Annual investment costs = $32,285/yr
326
-------
Operating Costs
Solid wastes handling a $0.30/ton = $15,000
Fond cleaning 3 $0.50/ton = 19,000
Maintenance = 15,000
Chemicals = 5,000
Power = 3,000
Labor (tnisc) - 5,000
Taxes and insurance 8 2%
of capital = 5,, 500
Total $67,500
Treatment Level C - Total recycle of process water using
pond system
Basis: Same as Level B except no discharge
Capital Costs
Ponds = $200,000
Pumps and piping = 75,000
Miscellaneous construction = 25,00.0
Total $300,000
Annual investment costs - $35,220
Operating Costs
Solids wastes handling d> $0.30/ton = $15,000
Fond cleaning 8 $0.50/ton = 19,000
Maintenance * 20,000
Chemicals = 5,000
Power = 5,000
Labor = 3,000
Taxes and insurance 9 2% of
capital * 6,000
Total $73,000
Treatment Level D - Thickener plus filter removal of suspended
solids. Generally pond systems are the preferred system for
removing suspended solids from waste water. In some instances,
however, when the land for ponds is not available or there are
other reasons for compactness, mechanical thickeners, clarifiers,
and filters are used. The basis is the same as for Level B,
except no pond is reguired.
Capital Costs
Thickener - 15 meter (50 ft.) diameter = $150,000
Filter system installed = 35,000
Pumps, tanks, piping, collection = 50,000
Conveyor = 5,000
327
-------
Building = 5,000
Total $245,000
At 10 yr life and 109S interest rate
Capital recovery factor = .1627
Annual investment costs = $39,862
Operating Costs
Solids wastes handling 8 $0.30/ton = $26,400
Maintenance = 20,000
Chemicals = 20,000
Power = 5,000
Labor = 3,000
Taxes and insurance a 2%
of capital = 5,000
Total $79,400
Treatment Level E - Thickener and filter removal of suspended
solids and recycle to eliminate discharge. The basis is the same
as for Level D, complete recycle of treated wastes.
Capital Costs
The same as for Level D - pumping and piping to surface
water discharge taken to be the same as for recycle
piping and pumping.
Operating Costs
The same as for Level D
Total annual costs = $119,300
DRY GRINDING PLANTS
There are no discharges from this subcategory.
WET GRINDING PLANTS
Of the three facilities involved, one sends its small amount of
waste water to nearby waste treatment facilities of much larger
volume, the second has no waterborne waste due to the nature of
its process and the third uses a settling pond to remove
suspended solids prior to water recycle. Total costs for waste
water treatment from this third operation are estimated as
$2.60/kkg of wet ground mica produced ($2.30/ton). A capital
investment of $65,000 is reguired.
328
-------
BARITE
Of the -twenty-seven known significant U.S. facilities producing
barite ore or ground barite, nine facilities use dry grinding
operations, fourteen use log washing and jigging methods to
prepare the ore for grinding, and four use froth flotation
techniques.
DRY GRINDING OPERATION
There is no water used in dry grinding facilities, therefore
there are no treatment costs.
WASHING OPERATIONS
The ratio of barite product to wastes vary greatly with ore
quality, but in all cases there is a large amount of solid waste
for disposal. Only about 3 to 7 percent by weight of the ore is
product. The remainder consists of rock and gravel, which are
separated and recovered at the facility, and mud and clay
tailings, which are sent as slurry to large settling and storage
ponds.
In Missouri, where most of the washing operations are located,
tailings ponds are commonly constructed by damming deep valleys.
It is customary in log washing operations to build the initial
pond by conventional earthmoving methods before the facility
opens so that process water can be recycled. Afterwards the rock
and gravel gangue are used by the facility to build up the dam on
dikes to increase the pond capacity. This procedure provides a
use for the gangue and also provides for storage of more clay and
mud tailings. The clay and mud are used to seal the rock and
gravel additions. All facilities totally recycle process water
except during periods of heavy rainfall when intermittent
discharges occur. A washing facility located in Nevada also uses
tailings ponds with total recycle of waste water and no discharge
at any time. The dry climate and the scarcity of water are the
factors determining the feasibility of such operation. In
Table 24 are estimated costs for treatment.
Operations in dry climates (e.g. Nevada) would be expected to
have treatment costs similar to Level A, even at no discharge
level. All facilities are currently at Level A or C. Some
facilities use Level B treatment partially. The necessity and
extent of such treatment depends on quality of water presently
discharged. Level C is not achievable in unfavorable terrain.
With favorable local terrain zero discharge of process water is
achievable. Known ages range from less than 1 to 19 years. Age
was not found to be a significant factor in cost variance. Both
geographical location and local terrain are significant factors
in treatment costs. Western operations in dry climates can
achieve no discharge at all times at a cost significantly below
329
-------
TABLE 24
BARI7E (WET PROCESS) TREATMT COSTS
PLANT SIZE I8'OQQ
PLANT AGE n YEARS
KKG
PER YEAR -OF
PLANT LOCATION Missouri or Nevada
INVESTED CAPITAL COSTS: $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS; $
ANNUAL 0 G M (EXCLUDING
POWER AMD ENERGY)
ANNUAL ENEHGY AND POY/ER
TOTAL ANNUAL COSTS $
COST/ KKG Borite
WASTE LOAD PARAMETERS
(mg/ liter)
Suspended solids
fron
Leod
pH
RAW
WASTE
LOAD
LEVEL
A
(MIN)
180,000
21,150
10,000
10,000
41,150
2.26
(5-327*
0.04-8.4*
X 03 -2.0*
6-9*
B
260,000
30,500
16,400
10,000
56,900
3.13
25*
1.0*
0.1*
6-9*
C
265,000
31,100
13,600
11,000
55,700
3.06
0
0
0
_.
D
E
LFVEL DESCRIPTION' *on>Y discharged during peri pa's of heavy rainfall
A. Complete recycle except in times of heavy rainfall
B . A plus treatment of all discharged water with lime and floccubnts
C. Complete recycle - no discharge at al! times (ability to achieve this level
depends on local terrain - not all plants are capable of attaining zero discharge)
All costs are cumulative.
330
-------
eastern operations. Costs vary significantly with local
watersheds, elevations, and availability of suitable terrain for
pond construction. Nine facilities in this subcategory have
production rates ranging from 11,000 to 182,000 kkg/yr (12,100 to
200,000 tons/yr). The representative facility is 18,000 kkg/yr
(20,000 tons/yr). Eight of the nine facilities have less than
30,000 kkg/yr production (33,000 tons/yr). The single large
facility in this subcategory that was investigated is the western
facility for which costs have been discussed earlier in this
section. For the eight eastern facilities, the capital costs are
estimated to be directly proportional to the 0.9 exponential of
size over this range/ and directly proportional for operating
costs other than taxes, insurance and capital recovery.
Capital Costs
Pond cost, $/hectare ($/acre)
(a) tailings ponds:
(b) clarification ponds:
12,350
7,400
(5,000)
(3,000)
Pond areas, hectares (acres)
(a) tailings ponds: 8.1
(b) clarification ponds: 8.1
Pumps and pipes: $50,000
Operating and Maintenance Costs
Power unit cost:
Pond maintenance:
Pump and piping maintenance:
Taxes and insurance:
Plocculants:
Lime:
FLOTATION OPERATIONS
(20)
(20)
$100/HP-yr
2% of pond investment
6X of non-pond investment
2% of total investment
$2.20/kg ($1.00/lb)
$22/kkg ($20/ton)
Flotation is used on either fceneficiated low grade ore or
high-grade ore which is relatively free of sands, clays, and
rocks. Therefore, they produce significantly less solid wastes
(tailings) than washing operations, and consequently less cost
for waste treatment.
Wastewater treatment is similar to that previously described for
washing operations: pond settling and storage of tailings
followed by recycle. Of the three facilities investigated in
this category two are in the east and one in the west. The
western facility achieves no discharge; the two eastern
facilities do not.
331
-------
Costs for the barite flotation process are given in Table 25.
Level A is currently achieved in the Nevada facility. Levels B
and C represent technology used ty present eastern operations.
Level D is for projected no discharge at eastern operations. At
eastern operations ability and costs to achieve no discharge
depend on local terrain. costs developed are for cases where
favorable terrain makes achievement of no discharge possible.
Ages for the three facilities ranged from 10 to 58 years. Age
was not found to be a significant cost variance factor. Both
geographical location and local terrain are significant cost
variance factors. western operations are able to achieve no
discharge at treatment costs below those for intermittent
discharge from eastern facilities. No known eastern facility
currently achieves no discharge. The flotation facilities range
from 33,600 to 91,000 kkg/yr (37,000 to 100,000 tons/yr). The
representative facility is 70,000 kkg/yr (77,000 tons/yr).
Treatment costs are essentially proportional to size in this
range.
Capi tal Costs
Tailings pond cost, $/hectare ($/acre): 7,400 (3,000)
Pond area, hectares (acres) : 20 (50)
Pumps and piping: $50,000
Chemical treatment facilities: $50,000
Operating and Maintenance costs
Pond maintenance: 2% of pond investment
Taxes and insurance: 2% of total investment
Power - $100/HP-yr
Treatment Chemicals
Lime: $22/kkg ($20/ton)
Flocculating agent: $2.20/kg ($1/lb)
MINE DRAINAGE
The mining of barite is a dry operation and the only water
normally involved is from pit or mine drainage resulting from
rainfall and/or ground seepage. Most mines do not have any
discharge. Rainwater in open pits is usually allowed to
evaporate. One known mine, however, has over 1.9 x 106 I/day
(0.5 mgd) of acidic ground seepage and rainwater runoff. Lime
neutralization and pond settling of suspended solids of this mine
drainage costs an approximate $2 per kkg of barite produced
($1.8/ton). Most of this cost is for lime and flocculating
agents.
332
-------
TABLE 25
BARITE (FLOTATION PROCESS) TREATOT COSTS
PLANT SIZE
70,000
PLANT AGE 33 YEARS
KKG
PER YEAR OF Bar5te
PLANT LOCATiON Missouri, Nevada, Georgia
INVESTED CAPITAL COSTS'. $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING Ah'D MAINTENANCE
COSTS: $
ANNUAL 0 £'; M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND PO\VER
TOTAL ANNUAL COSTS $
COST/ KKn Barite
WASTE LOAD PARAMETERS
(mg/liter)
Suspended Solids
phi
Rft.W
WASTE
LOAD
:50,000
-
LEVEL
A
(WIN)
150,000
17,600
6,000
10,000
33,600
0.49
0
-
(mm)
200,000
23,480
7,000
15,000
45,480
0.67
3-250
6-9
C
250,000
31,600
12,000
15,000
58,600
0.86
25
6-9
D
310,000
36,400
11,400
15,000
62,800
0.92
0
-
E
LEVEL DESCRIPTION:
7T. ~PoncF sefrling oi solids plus recycle of wafer to process; no discharge (western operation)
B. Pond settling of solids plus recycle of water to process; intermittent discharge; no chemical
treatment for discharged water
C. B plus chemical treatment with lime and/or flocculating agent to adjust pH end reduce
suspended solids
D. B plus additional pond capacity for total impoundment (requires favorable local terrain)
333
-------
FLUOFSPAR
Beneficiation of mined fluorspar ore is accomplished by heavy
media separations and/or flotation operations. Although these
technologies are used separately in some instances, generally
beneficiation facilities employ both techniques.
HEAVY MEDIA SEPARATIONS
The primary purpose of heavy media separations is to provide an
upgraded and preconcentrated feed for flotation facilities. Five
of the six heavy media operations have no waste water discharge.
The sixth facility uses a pond to remove suspended solids then
discharges to surface water. Wastewater treatment costs are
given in Table 26. Level A technology is achieved by all
facilities. Level B is currently achieved by 5 of the 6.
Ages for this subcategory range from 1 to 30 years. Age was not
found to be a significant factor in cost variance. Facilities
are located in the Illinois-Kentucky area and southwestern U.S.
There are facilities with no process effluents in both locations.
Location is not a significant factor in cost variance. The
facilities having heavy media facilities range from 5,900 to
81,800 kkg/yr (6,500 to 90,000 tons/yr) production. The
representative facility is 40,000 kkg/yr (45,000 tons/yr). Since
thickeners are the major capital investment, capital costs are
estimated to be directly proportional to the 0.7 exponential of
size. Operating costs other than taxes, insurance and capital
recovery are estimated to be directly proportional to size.
Capital Costs
Pond cost, $/hectare ($/acre): 7,400 (3,000)
Pond size, hectares (acres): 4 (10)
Pumps and piping costs: $20,000
Thickeners: $50,000
Operating and Maintenance Costs
Pond maintenance: ' 2% of pond investment
Pumps and piping maintenance: 6% of investment
Pond cleaning: 15,000 ton/yr 3) $.35/ton
Power: $100/HP-yr
FLOTATION SEPARATIONS
Wastewater from flotation processes are more difficult and costly
to treat and dispose of than those from heavy media separation.
The bulk of the solid wastes from the ore are discharged from the
flotation process. Flotation chemicals probably interfere with
settling of suspended solids and fluoride contents are higher
than in the heavy media process.
334
-------
TABLE 26
FUJORSPAR (HMS PROCESS) TREATMENT COSTS
PLANT SIZE
40,000
KKG
PER YEAR/OF fluorspar
PLANT AGE 8 YEARS PLANT LOCATION M?dwest
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/ K^G fluorspar
WASTE LOAD PARAMETERS
(kg/ kkg of fluorspar )
Suspended solids
Dissolved Fluoride
Lead
Zinc
pH
RAW
WASTE
LOAD
340
0.04
«
-
-
LEVEL
A
(MIN)
50,000
5,850
7,050
2,500
15,400
0.38
0.13
0.04
0.0002
0.0012
6-9
B
70,000
8,200
8,250
5,000
21,450
0.52
0
0
0
0
0
c
D
E
X
LEVEL DE
A. Spiral classifier followed by small pond with discharge
B. Thickener plus total recycle
All costs are cumulative.
335
-------
Cost estimates for waste water treatment from a representative
flotation facility are given in Table 27. Level A is typical of
Kentucky-Illinois area waste water treatment. Level B represents
costs for planned future treatment for these operations. Level C
represents treatment technology used for municipal water, but not
currently used for any fluorspar waste water.
In the fluorspar flotation category facility ages range from 1 to
35 years. Age has not been found to be a significant factor in
cost variance of treatment options. Both geographical location
and local terrain are significant cost variance factors. Dry
climate western operations can achieve no discharge at lower
costs than midwestern operations can meet normal suspended solids
levels in their discharges. Facility sizes range from 13,600 to
63,600 kkg/yr (15,000 to 70,000 tons/yr). The representative
facility size is 40,000 kkg/yr (45,000 tons/yr). The capital
costs are estimated to be directly proportional to the 0.9
exponential of size over this range and directly proportional for
operating costs other than taxes, insurance, and capital
recovery.
Capital costs
Pond cost, $/hectare ($/acre): 12,350 (5,000)
Pond size, hectares (acres): 10 (25)
Operating and Maintenance Costs
Labor: $5.00/hr
Power: $100/HP-yr
Taxes and insurance: 2% of investment
Flocculating chemicals: $2.20/kg ($1/lb)
Lime: $22/kkg ($20/ton)
Alum: $55/kkg ($50/ton)
FLUORSPAR DRYING AND PELLETIZING PLANTS
There are three significant fluorspar drying facilities. Two of
these facilities are dry operations. The third has a wet
scrubber but treats the effluent as part of HF production wastes.
Pelletizing facilities are also dry operations.
MINE DRAINAGE
Fluorspar mines often have significant drainage. Normally the
fluoride content is 3 mg/1 or less and suspended solids are low.
Even when higher concentrations of suspended solids are present,
settling in ponds is reported to be rapid, cost for removing
these solids are estimated to be $0.01 to $0.05 per kkg or ton of
fluorspar produced.
336
-------
TABLE 27
FLUORSPAR (FLOTATION PROCESS) TREATOJT COSTS
PLANT SIZE 40,000
KKG
PER YEAR OF fluorspar
PLANT AGE l5 YEARS PLANT LOCATION Midwest
INVESTED CAPITAL COSTS: $
TOTAL
t
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: - $
ANNUAL 0 Q M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ Yy of Producl-
WASTE LOAD PARAMETERS
(kg/ KKG of Product )
Suspended solids
Dissolved fluoride
RAW
WASTE
LOAD
2,000
0.05-0.2
LEVEL'
A
(MIN)
130,000
15,300
24,600
8,000
47,900
1.20
5-35
0,05-0.2
B
135,000
21 ,700
53,700
10,000
85,400
2.14
0.3-0.6
0.05-0.2
C
185,000
21 ,700
69,700
10,000
101 ,400
2.54
0.2-0,4
0.05-0.1
•
D
E
LEVEL DESCRIPTION
A - pond settling and discharge
B - A plus treatment with flocculants
C - A plus alum treatment
All costs are cumulative.
337
-------
SALINES FROM ERINE LAKES
The extraction of several mineral products from lake brines is
carried out at two major U.S. locations: Searles Lake in
California and the Great Salt Lake in Nevada. Also lithium
carbonate is extracted at Silver Peak, Nevada. The only wastes
are depleted brines which are returned to the brine sources.
There is no discharge of waste water and no treatment costs.
BORATES
The entire U.S. production of borax is carried out in the desert
areas of California by two processes: the mining and extraction
of borax ore and the trona process. The latter is covered in the
section on salines from lake brines. The trona process has no
waste water treatment or treatment costs since all residual
brines are returned to the source. The mining and extraction
process accounts for about three-fourths of the estimated U.S.
production of borax. All waste water is evaporated in ponds at
this facility. There is no discharge to surface water. Costs
for the ponding treatment and disposal are given in Table 28.
Since there is only one facility, minimum treatment and no
discharge treatment costs are identical.
Capital Costs
Pond cost, $/hectare ($/acre): 20,000 (8,000)
Pond area, hectares (acres): 100 (250) •
Pumps and piping: $500,000
Operating and Maintenance Costs
Pond maintenance: 255 of pond investment
Pump and piping maintenance: 6% of pump and piping investment
Power: $100/HP-yr
Taxes and insurance: 2% of total investment
338
-------
TABLE 28
BORAHS TREATOTT COSTS
PLANT SIZE 1/000,000
KKG
PER YEAR/OF Borates
PLANT AGE I7 YEARS PLANT LOCATION
INVESTED CAPITAL COSTS! $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERAflNG AND MAINTENANCE
COSTS: $
ANNUAL 0 Q M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG Borates
WASTE LOAD PARAMETERS
(kg/ ^0 of Borates )
"
Solid wastes (insol.)
Soluble wastes
RAY/
WASTE
LOAD
800
2.5
LEVEL
A
(M1N)
>,500,000
293,500
120,000
30,000
443,500
0.44
0
0
B
C
D
E
LEVEL D£SCff/PT/O.v;
A - evaporation of all wastewator in ponds.
All costs are cumulative.
339
-------
POTASH
Potash is produced in four different locations by four different
processes, all of which are in dry climate areas of the western
U.S. Two processes, involving lake brines, have no waste water.
All residual brines are returned to the lake. There are no
treatment costs. The third process (Carlsbad Operations), dry
mining followed by wet processing to separate potash from sodium
chloride and other wastes, utilizes evaporation ponds for
attaining no discharge or waste water. Treatment costs are given
in Table 29. The fourth process (Moab Operations) involves
solution mining followed by wet separations. This process also
has no discharge of waste water. Treatment costs are given in
Table 30.
Age is not a cost variance factor. All facilities are located in
dry western geographical locations. Location is not a
significant factor on costs. Known facility sizes range from
450,000 to 665,000 kkg/yr (500,000 to 730,000 tons/yr) for
Carlsbad Operations. There is only one facility in the Moab
Operations category. There is no significant cost variance
factor with size for the Moab or Carlsbad Operations
subcategories.
Cost Basis for Table 29
Capital Costs
Pond cost, {/hectare ($/acre): 2,470 (1,000)
Evaporation pond area, hectares (acres) : 121 (300)
Pumps and piping: $100,000
Operating and Maintenance Costg
Maintenance, taxes and insurance: H% of investment
Power: $100/HP-yr
Cost Basis for Table 30
Capital Costs
Dam for canyon: $100,000
Pumps and piping: $250,000
Operating and Maintenance Costs
Labor: $10,000
Maintenance: Q% of investment
Taxes and insurance: 2% of investment
Power: $100/HP-yr
340
-------
TABLE 29
POTASH (CARLSBAD OPERATIONS) TREATMENT COSTS
PLANT SIZE
PLANT AGE
500,000
KKG
30
YEARS
PLANT LOCATION
PER YEAR
New Mexico
Potash
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/ KKG P°tash
WASTE LCAD PARAMETERS
(kg/ kke of Potash )
Sodium chloride
Clays
Magnesium sulfate
Potassium sulfate
Potassium chloride*
RAW
WASTE
LOAD
0-3750
15-235
0-640
0-440
0-318
LEVEL
A
(MIN)
400,000
47,000
8,000
71,000
0.14
0
0
0
0
0
B
C
D
E
LEVEL DCSCftJPT/0/y:
A - Evaporation ponds
*cisDr7ne
All costs are cumulative.
341
-------
TABLE 30
POTASH (MOAB OPERATIONS) TREATOT COSTS
PLANT SiZE 20°'°00
KKG
PLANT AGE
10
YEARS
PLANT LOCATION
PER YEAR OF Potash
Utah
INVESTED CAPITAL COSTS! $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND f/AINTENANCE
COSTS: $
ANNUAL 0 8, M "(EXCLUDING
POV/ER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
$
COST/ KKG potash
WASTE LOAD PARAMETERS
(Kg/ vu-. of potash) )
Sodium chloride
•
RAW
WASTE
LOAD
640
LEVEL'
A
(MIN)
350,000
56,950
45,000
5,000
106,950
0.53
0
B
C
D
E
LEVEL DESCRIPTION:
A - Holding pond plus on-land evaporation
All costs are cumulative.
342
-------
TRONA
All U.S. mining of trona ore is in the vicinity of Green River,
Wyoming. There are four mining facilities, three of which also
process ore to pure sodium carbonate (soda ash). The fourth
facility has only mining operations at this time. Wastewater
from these operations come from mine drainage, ground water and
process water.
PROCESS WATER
Of the three processing facilities, two have no discharge of
process water and one does. Plans are under way at this one
facility to eliminate process water discharge. Table 31 gives
cost estimates for both treatment levels for the hypothetical
representative facility.
The ages of the three processing facilities range from 6 to
27 years. Age was not found to be a significant factor in cost
variance. All facilities are located in sparsely populated areas
close to Green River, Wyoming. Geographical location is not a
significant cost variance factor. Local terrain variations are a
factor. Some desired or existing pond locations give seepage and
percolation problems; others do not. The costs to control
seepage or percolation in an area with unfavorable underlying
strata can be considerably more than the original installation
cost of a pond in an area with no seepage problems. The costs
are valid for locations with minor pond seepage problems, which
at present is the typical case. For locations with bad seepage
problems, the costs of an interceptor trench to an impermeable
strata plus back-pumping should be added. Based on 1973 soda ash
production figures, the three processing facilities are
approximately of the same size. All of these facilities are
substantially increasing their output over a period of time.
Size is not a significant factor in cost variance from facility-
to-facility.
Capital Costs
Pond cost, S/hectare ($/acre): 7,400 (3,000)
Pond area, hectares (acres)
Level A: 162 (400)
Level B: 271 (670)
Pumps and piping
Level A: $300,000
Level B: $400,000
Operating and Maintenance Costs
Pond maintenance: 2% of pond investment
Pump and piping maintenance: 6% of pond investment
3U3
-------
TABLE 31
TRDNA TREATMT COSTS
PLANT SIZE 1,000,000
PLANT AGE 15 YEARS
KKG
PLANT LOCATION
PER YEAR -OF Soda Ash
Wyoming
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/ KKG soda ash
WASTE LOAD PARAMETERS
(Kg/ kke of soda ash }
Suspended Solids
Dissolved Solids
RAW
WASTE
LOAD
5
35
LEVEL
A
(MIN)
1,500,000
176,100
102,000
80,000
358,100
0.36
0.005
0.06
B
2,400,000
282,100
1 60,000
100,000
542,000
0.54
0
0
C
D
E
All costs are cumulative.
A
B
Evaporation ponds with small discharge
Evaporation ponds with no discharge
344
-------
Taxes and insurance: H% of total investment
Power: $100/HP-yr
MINE DRAINAGE
All of the four mines have some drainage. The average flow mines
is 0.64 x 10* I/day (0.17 mgd). This is approximately 10 percent
of average process water and is estimated on this basis to cost
$0.01 to $0.05 per kkg or ton of soda ash produced for ponding
and evaporative treatment. One facility currently has an
unusually high mine pumpout volume, 1.8 x 10* I/day (0.43 mgd).
The costs to contain and evaporate this amount are
proportionately higher.
GROUND WATER AND RUNOFF WATER
Ground water and runoff water are also led to collection ponds
where settling and substantial evaporation take place. On the
basis of known information no meaningful cost estimate can be
made, since the amounts are extremely variable and, nevertheless,
small compared to the process water volume.
345
-------
SODIUM SULFATE
Sodium sulfate is produced from natural sources in three
different geographical areas by three different processes:
(1) Recovery from the Great Salt Lake;
(2) Recovery from Searles Lake brines;
(3) Recovery from west Texas brines.
Processes (1) and (2) have no waste water treatment or treatment
costs. All residual brines are returned to the lakes. Process
(3) has waste water which is percolated and evaporated in
existing mud flat lakes. There is no treatment. The waste water
flows to the mud lake by gravity. Costs are almost negligible
(estimated as $0.01 to $0.05 per kkg or ton of sodium sulfate
produced) .
346
-------
ROCK SALT
This study covers those facilities primarily engaged in mining,
crushing and screening rock salt. Some of these facilities also
have evaporation operations with a common effluent. The waste
water from mining, crushing and screening operations consists
primarily of a solution of varying sodium chloride content which
comes from one or more of the following sources:
(1) wet dust collection in the screening and sizing step;
(2) washdown of miscellaneous spills in the operating area and
dissolving of the non-saleable fines;
(3) seepage from mine shafts.
runoff from salt piles
Wastewater volumes are usually fairly small, less than
500,000 I/day (130,000 gal/day), and are handled in various ways,
including well injection and surface disposal. Well injection
costs for minewater drainage are estimated to be in the range of
$0.01 to $0.05 per kkg or short ton of salt produced. Surface
disposal is costed in Table 32. Most often there is no treatment
of the miscellaneous saline waste water associated with this
subcategory. Some facilities use settling ponds to remove
suspended solids prior to discharge. In the event that land is
not available for ponds, costs for alternate technology using
clarifiers instead of ponds are given in Level C. Age, location,
and size are not significant factors in cost variance.
Capital Costs
Pond cost, $/hectare ($/acre) : 49,000 (20,000)
Pond size, hectares (acres): 0.2 (0.5)
Pumps and piping cost: $5,000
Clarifier: $35,000
Operating and Maintenance
Pond maintenance: 2% of pond investment
Pump and piping maintenance: 10% of pump and piping
investment
Power: $100/HP-yr
Taxes and insurance: 2% of total investment.
For alternative D, an actively used storage silo of 100,000
tons capacity is assumed.
347
-------
TABLE 32
ROCK SALT TREATIW COSTS
PLANT SIZE
1,000,000
PLANT AGE 30 YEARS
KKG
PER YEAR --OF salt
PLANT LOCATION Eastern United States
INVESTED CAPITAL COSTS! $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 a M (EXCLUDING
POV.'F.R AND ENERGY)
ANNUAL ENERGY AND PO\VER
TOTAL ANNUAL COSTS $
COST/ KKG sa|f
WASTE LOAD PARAMETERS
(kg/ vkp of salt )
Suspended solids
Dissolved solids
RAW
WASTE
LOAD
0-0.9
LEVEL
A
(WIN)
0
0
0
0
0
0
0-0.9
B
15,000
1,760
700
500
2,960
<0.01
0.009
C
50,000
8,150
3,000
3,000
13,150
0.01
0.009
D
523,000
85,300
23,000
2,000
110,300
11
0
E
••
LEVEL D:;SCR/PTJO;V:
All costs are cumulative.
A — No wastewater treatment
B — Pond settling of suspended solids followed by discharge
C — Clarifier removal of suspended solids followed by discharge
D- Salt storage pile structures
348
-------
PHOSPHATE ROCK
Phosphate ore is mined in four different regions of the U.S.:
Florida: 78% of production
North Carolina: 5% of production
Tennesse: 5% of production
Western States: 12% of production
For purposes of costs the above production may be separated into
two groups: eastern operations and western operations.
EASTERN OPERATIONS
The beneficiation of phosphate ore involves large volumes of
waste water. In addition, there are large quantities of solid
wastes. Baw wastes, sand, and small particle sized slimes in the
process raw wastes exceed the guantity of phosphate product.
Essentially two waste water streams come from the process: sand
tailings stream and a slimes stream. The sand tailings settle
rapidly for use in land reclamation. The water from this stream
can then be recycled. Slimes, on the other hand, settle fairly
rapidly but only compact to 10-20 percent solids. This mud ties
up massive volumes of water in large retention ponds. Most of
the process waste water treatment costs are also tied up in the
construction of massive dams and dikes around these ponds. All
mine and beneficiating facilities practice complex water control
and reuse. The extent of control and reuse depends on many
factors, including:
(1) topography
(2) mine-beneficiating facility waste pond layouts
(3) age of facilities
(H) fresh water availability
(5) regulations
(6) level of technology employed
(7) cost.
Most water discharges are intermittent; heavy during the wet
season (3-6 months/yr), slight or non-existent during dry seasons
(6-9 months/yr). Water discharged during the wet season due to
insufficient storage capacity could be used during the dry
season, if enough empty pond space is available.
Since water control fundamentally involves storage and transport
(pumping) operations, by construction of additional storage pond
and piping and pumping facilities almost any degree of process
waste water control may be achieved up to and including closed
cycle. No discharge of process water involves two premises:
(1) Only process water is contained. Mine drainage is isolated
and used as feed water or treated (if needed) and discharged
349
-------
separately. Rainwater runoff is also treated separately, if
needed.
(2) Evaporation-rainfall imbalances are more than counterbalanced
by water losses in slime ponds. Slime ponds are essentially
water accumulation ponds where water is removed from recycle
by holdup in the slimes.
All costs are for treatment and storage of suspended solids.
There is no treatment applied specifically for fluorides or
phosphates although existing treatment will result in a degree of
removal of these pollutants. Table 33 gives costs for three
levels of treatment technology. All facilities use Level A
technology, and most use some degree of Level B technology.
Level C technology is currently not used. All discharged wastes
are expressed in concentrations, since the volume of waste water
discharges from the facilities vary widely depending on age,
terrain, local rainfall, and water control practice. Most
facilities currently achieve less than 30 mg/1 suspended solids
as a monthly average at Level A. Those that do not would be
expected to have the additional expenditures of Level B to reach
30 mg/1 suspended solids.
Facilities representing the eastern phosphate rock subcategory
range in age from 3 to 37 years. Age was not found to be
significant factor in cost variance. Operations are located in
Florida, North Carolina and Tennessee. Pond construction is
different in Tennessee, which is hilly, than in flat areas such
as Florida and North Carolina. Flat area facilities have diked
ponds while in Tennessee facilities use dammed valleys. A
comparison indicates that construction costs are approximately
the same for both areas and location is not a significant factor
in cost variance. The facilities in the eastern grouping range
in size from 46,300 to 4,090,000 kkg/yr (51,000 to
4,500,000 tons/yr). The representative facility is
2,000,000 kkg/yr (2,200,000 tons/yr). Capital costs are
estimated to be directly proportional to the 0.9 exponent of size
and directly proportional for operating costs other than taxes,
insurance and capital recovery.
Capital Costs
Pond cost, $/hectare ($/acre): 17,300 (7,000)
Pond area, hectares (acres): 400 (1,000)
Pumps and piping: $1,000,000
350
-------
TABLE 33
PHOSPHATE ROCK (EASTERN) TREATOJT COSTS
PLANT SIZE 2,000,000 KKG PER YEAR-OF product
PLANT AGE 15 YEARS PLANT LOCATION Florida-North Carolina-Tennessee
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/ product
W\STE LOAD PARAMETERS
(mg/liter)
Suspended Solids
Dissolved Fluoride
Phosphorus (total)
RAY/
\VASTE
LOAD
LEVEL
A
(MIN)
8,000,000
804,000
360,000
240,000
1,404,000
0.70
3-560
2*
4*
B
8,650,000
910,000
389,000
300,000
1,599,000
0.80
<30
2*
4*
C
1 2,000,000
1,560,000
429,000
335,000
2,324,000
1.16
0
0
0
D
E
.
/ R/H n,^r:r?/PT/.O.V * Estimated average values.
A — Pond treatment of slimes and sand tailings
B — A plus improved process water segreation
C — Pond treatment plus impoundment of all process water
All costs are cumulative.
351
-------
Operating and Maintenance Costs
Labor and maintenance: 2.516 of total investment
Taxes and insurance: 2% of total investment
Power: $100/HR-yr
WESTERN OPERATIONS
Because of the favorable rainfall-evaporation balance existing
for western phosphate mines and processing facilities, all
facilities are either at the no discharge level or can be brought
to this level. Of six operating areas, five have no discharge.
Table 3H gives cost of waste water treatment technology for
western operations.
The six western operations range in age from 6 to 27 years. Age
was not found to be a significant cost variance factor. Ail
facilities in this sufccategory are located in Idaho, Wyoming and
Utah. Location is not a significant cost variance factor.
Facilities in this subcategory range in size from 296,000 to
909,000 kkg/yr (326,000 to 1,000.000 tons/yr). The
representative facility is 500,000 kkg/yr (550,000 tons/yr).
Over this range of sizes, capital costs can be estimated to be
directly proportional to the exponent of 0.9 to size, and
operating costs other than capital recovery, taxes and insurance
are approximately directly proportional to size.
Capital Costs
Pond costs, $/hectare ($/acre): 1,900 (2,000)
Pond size , hectares (acres): 100 (250)
Thickener: $200,000
Pumps and piping: $150,000
Operating and Maintenance Costs
Labor and maintenance: 2.5% of investment
Power: $100/HP-yr
Taxes and insurance: 2% of investment
MINE DRAINAGE
The high water table plus the heavy seasonal rainfall in most of
the eastern mining areas usually causes the mining pits to
collect water. Whenever feasible, mine drainage is used for
slurrying phosphate matrix to the beneficiation process. When
this is not possible, drainage can be pumped into other mined out
pits. Mine drainage involves primarily on-property water
control. Any that is may be expected to be treated as waste
water. Treatment costs are roughly estimated at $0.01 to
$0.05 per kkg or ton of product.
352
-------
TABLED
PHOSPHATE ROCK (WESTERN) TREATFBfT COSTS
PLANT SIZE
500,000
PLANT AGE 10 YEARS
KKG
PER YEAR "OF product
PLANT LOCATION Idaho-Utah
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
9
COST/ ££Q product
WASTE LOAD PARAMETERS
(kg/ kkS of product }
,._ Suspended solids _ ..
Fluoride (as ion)
Phosphorus (total)
RAW
WASTE
LOAD
1700
-
-
LEVEL
A
(MIN)
850,000
93,500
38,500
50,000
182,000
0.36
<0.05
< 0.001
< 0.001
B
1,250,000
140,500
56,500
75,000
272,000
0.54
0
0
0
C
D
E
.
LEVEL
A — Thickener plus evaporation ponds; discharge of residual to surface water
B — • Level A plus additional evaporation ponds to give no discharge.
All costs are cumulative.
' 353
-------
SULFUR (FRASCH PROCESS)
There are two sutcategories of sulfur mining:
(1) anhydrite deposit mining;
(2) on-shore salt dome mining;
ANHYDRITE DEPOSIT MINING
The following is a comparison of waste water from mining of
sulfur from anhydrite deposits to that from mining of salt dome
deposits:
(1) The porous structure of anhydrite deposits absorbs more of
the injected water and reduces the amount of bleedwater.
(2) Since the anhydrite deposits are not filled with salt,
bleedwater is lower in dissolved solids than the average for
salt dome bleedwater. Anhydrite mines recycle this
bleedwater to the formation.
(3) The location of anhydrite mines is in western Texas where the
dry climate makes it possible to evaporate waste water. Salt
dome mines are in Louisiana and east Texas which have more
rainfall.
Treatment and cost options are developed in Table 35 for complete
recycle of anhydrite deposit mining bleedwater. Since both
anhydrite deposit mines are now accomplishing this level, the
costs also represent minimum level treatment technology. Most of
the costs are for water treatment chemicals for the recycled
bleedwater.
The anhydrite deposit mining subcategory consists of two
facilities, 5 and 7 years of age. Age is not a significant cost
variance factor. Both facilities are located in western Texas.
Location is therefore not a significant cost variance factor.
Based on water treatment costs supplied by both facilities, size
in existing facilities is not a significant cost variance factor.
Capital Costs
Water treatment installations: $300,000
Thickeners and evaporation ponds: $100,000
Pumps and piping: $150,000
Operating and Maintenance Costs
Bleedwater volume, I/day (mgd): 18.9 x 106 (5.0)
Bleedwater treatment, $/1,000 liters (gallons): $0.09 ($0.35)
The energy and power costs were supplied by facility 2020
354
-------
TABLE 35
SULFUR (ANHYDRITE) TREATTBH COSTS
PLANT SIZE 1,000,000
PLANT AGE 6 YEARS
KKG
PLANT LOCATION
PER YEAR OF sulfur
Western Texas
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/ KKG sulfur
V/ASTE LOAD PARAMETERS
(kg/ kkg of sulfur )
Water softener sludge
Suspended solids
Dissolved solids
RAW
WASTE
LOAD
12.5
-
2ino-
43.?
LEVEL
A
(WIN)
550,000
90,000
705,000
30,000
825,000
0.83
0
0
B
C
D
E
LEVEL DESCRIPTION:
A — Recycle of all bleedwater, use of on-site evaporative disposal of water
.,, softener sludges.
All costs are cumulative.
355
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ON-SHORE SALT DCME MINING
There are nine facilities in the U.S. producing sulfur from on-
shore salt dome operations. The wide variability of bleedwater
quantity per ton of sulfur produced has been taken into account
by expressing all pollutants in terms of concentration rather
than weight units. Cost analyses for on-shore salt dome sulfur
facilities are given in Table 36. Several companies are using
(or have used) Level A technology, at least one uses Level B as
part of their treatment, one uses Level C, five use Level D, one
uses Level E, one Level F and no one currently uses Level G.
Level G is included to show the costs for complete oxidation of
all sulfides, in the bleedwater to sulfates.
The on-shore salt dome sulfur mining subcategory consists of 9
facilities ranging in age from 6 to 45 years. Age is not a
significant cost variance factor. All facilities are located in
eastern Texas and Louisiana. Geographical location is a
significant cost variance factor only in that lengthy ditches (up
to 37 km or 22 miles) often had to be dug to get the bleedwater
discharge to suitable surface water. All facilities now have
such outlets. New facilities in this subcategory would have to
make such provisions, guite likely at major expense. The nine
facilities in this subcategory range from 150,000 to
1,270,000 kkg/yr (165,000 to 1,400,000 tons/yr). The
representative facility is 500,000 kkg/yr (550,000 tons/yr). The
capital costs over this size range are estimated to be directly
proportional to the 0.8 exponential of size for process equipment
treatment facilities such as Levels C and F, 0.9 exponential for
mixed facilities such as Level E and directly proportional to
size for Level D pond treatment. Operating costs other than
taxes, insurance and capital recovery are estimated to be
directly proportional to size.
The costs are assumed to be directly proportional to the
bleedwater volume per unit of production. Exclusive of sea water
dilution, the range of relative bleedwater volumes found was
6,900 to 22,100 1/kkg (1,700 to 5,300 gal/ton).
Capital costs for Levels C through F were taken from industry
supplied values and adjusted for size. Level G is based on
500 mg/1 of sulfides in 18.9 x 10* I/day (5 mgd of bleedwater).
Operating and maintenance costs for Levels C through F were taken
from industry supplied values. The chlorine costs for Level G
are $110/kkg ($100/ton).
OFF-SHORE SALT DCME MINING
There is only one operational off-shore salt dome facility.
Bleedwater is directly discharged without treatment into the Gulf
of Mexico. Dissolved methane gas occurring naturally in the
bleedwater provides initial turbulent mixing of bleedwater and
356
-------
TABLE 36
SULFUR (ON-SHORE SALT DOME) TREA7MT COSTS
PLANT SIZE
500,000
PLANT AGE 26 YEARS
KKG
PER YEAR -OF sulfur
PLANT LOCATION Louisiona-East Texas
„
INVESTED CAPITAL COSTS:
. . . _ _ S
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: . $
ANNUAL 0 a M (EXCLUDING
POV/ER AND ENERGY)
ANNUAL ENERGY AND POY.'ER
TOTAL ANNUAL COSTS $
COST/ KKG sulfur
V.'ASTE LOAD PARAMETERS
Sulfide, ma/lifer
Suspended solids, mg/litcr
RA',7
Y.'ASTE
LOAD
600-
IOC.CL
<50
LEVEL . ^
A
(MINI)
50,000
5,870
2,500
1,000
9,370
0.02
500
<50
B
50,000
5,870
5,000
20,000
30,870
0.06
200-400
<50
C
1,540,000
250,000
145,000
10,000
405,500
0.81
<1
<50
D
3,200,000
375,700
1 02,000
10,000
488,400
0.98
< 1
<50
E F
1 ,500,000 3,000,000
176,000 • 488,000
300,000
100,000
570,000
1.15
' •
<1
<50
415,000
25,000
928,000
1.86
•
<1
30
G
20,000
3,200
3,400,000
1,000
3,404,000
6.80
i
j
0
<50
LEVEL .Ei'
A — Flashing of hydrogen sulfide from bleedwater
B — Spray aeration
C — Flue gas skipping reaction plus ponding
D — Large oxidation and settling ponds
E — Acrolion in small ponds followed by mixing of partially treated bteedwator with
10-20 times its volume* of oxygen-containing water
F — Cnomicol treatment \vilh sulfuious acid
G— Chemical treatment with chlorine
357
-------
sea water. Dissolved oxygen in the sea water reacts with the
sulfides present. Current practice and two additional treatment
technologies and their estimated costs are given in Table 37.
Level A represents present technology; Level B is piping of all
bleedwater to shore (10 miles away) followed by on-shore ponding
treatment; Level C is off-shore chemical treatment of sulfides
with chlorine. Level B is predicated on right-of-way and land
availability, which has yet to be established, for pipeline and
pond construction. Level C technology is not currently utilized
in any existing sulfur production facility.
Capital Costs
Pumps and piping:
Land cost, $/hectare ($/acre):
Land area, hectares (acres):
Pond cost, $/hectare, ($/acre):
Dilution pumping station:
New off-shore platforms:
Pumps and piping:
Chemical treatment facilities:
Construction overhead:
Operating and Maintenance Costs
$10,200,000
12,300 (50,000)
40 (100)
6,200 (2,500)
$520,000
$4,200,000
$2,200,000
$200,000
20% of direct costs
Labor and maintenance: Q% of investment
Power: $100/HP-hr
Chlorine, dollars/kkg (dollars/ton): 110 (100)
Taxes and insurance: 2% of investment costs
358
-------
TABU 37
SULFUR (OFF-SHORE SALT DOME) TREATMT COSTS
PLANT SIZE
1,000,000
PLANT AGE 14 YEARS
KKG
PLANT LOCATION
PER YEAR -OF sulfur
Off-Shore Louisiana
INVESTED CAPITAL COSTS! $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 & W (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG sulfur
WASTE LOAD PARAMETERS
(kg/ tto ^f sulfur )
Suspended Solids
Su! fides
RAW
WASTE
LOAD
0.3
5.5
LEVEL
A
(M!N)
0
0
0
0
0
0
0.3
5.5
B
13/50,000
2,237,000
1,385,000
200,000
3,822,000
3.82
0.2
0.03
C
7,920,000
1,288/500
6,21 2,000
100,000
7,600,600
7.60
0.2
0.03
D
E
LEVEL . P
A — Use of oxygen in seawater to oxidize sulfides
B — All bleea'wafer pumped to shore followed by on-shore ponding and mixing
with ambient water to oxidize sulfides
C — Off-shore chemical oxidation of sulfides with chlorine
All costs are cumulative.
359
-------
MINEPAL PIGMENTS (IRON OXIDE PIGMENTS)
One of two processes are used depending on the source and purity
of the ore. For relatively pure ores, processing consists simply
of crushing and grinding followed by air classification. This is
a dry process which uses no water and has no treatment costs.
Alternatively, for less pure ores, a washing step designed to
remove sand and gravel, followed by dewatering and drying is
used. This process has waste water treatment costs. Table 38
gives cost estimates for waste water treatment for this wet
process.
The one facility found using the wet process has an age of
50 years. Age is not believed to be a significant factor for
cost variance. Location was not found to be a significant factor
for cost variance. Only one facility was found using the wet
process. Size is not believed to be a significant factor for
cost variance.
Capital Costs
Pond cost, $/hectare ($/acre) : 24,700 (10,000)
Settling pond area, hectares (acres): 0.40 (1)
Pumps and piping: $5,000
Operating and Maintenance Costs
Maintenance: 14% of investment
Power: $100/HP-yr
Taxes and insurance: 2% of investment
360
-------
MINERAL
TABLE 38
TREATMT COSTS
PLANT SIZE ' 3,000
PLANT AGE 50 YEARS
KKG
PLANT LOCATION
PER YEAR.OF product
Eastern United States
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/ KKG product
WASTE LOAD PARAMETERS
(|;g/ kkS of product }
Suspended Solids
RAW
WASTE
LOAD
—
LEVEL
A
(WIN)
15,000
1,750
900
500
3,250
1.08
2.3
B
20,000
2,530
1,200
1,000
4,550
1.52
0
C
D
E
-
LEVEL DESCRIPTION:
A — Pond settling and discharge
B — Pond settling and total recycle
All costs are cumulative.
361
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LITHIUM MINERALS
There are only two facilities mining and processing spodumene ore
in the U.S. At both facilities the process water recycle is
90 percent or greater. The remainder is discharged. Large
volumes of solid wastes are inherent to the process. These
wastes are stored and/or disposed of by a combination of the
following means:
(1) Landfill or land storage of solids;
(2) Storage of settled solids in ponds;
(3) Processing and recovery as salable by-products; and
(4) A small portion is discharged to surface water as suspended
or dissolved materials.
The two facilities differ as to the above options employed.
Processing and recovery or by-prcducts also introduces new wastes
into the waste water that are not present otherwise. Therefore,
the treatment technologies and costs developed in Table 39
represent the best estimate of composite values for both
facilities. Level A represents present performance and Level B
future performance. Level B is based mainly on projected
installations for which the two facilities have supplied
technology and cost information. Age was not found to be a
significant factor in cost variance. Both facilities are located
in North Carolina.
Capital Costs
Pond costs, $/hectare {$/acre) : v 7,i»00 (3,000)
Pond area, hectares (acres): 50 (125)
Pumps and piping: $100,000
Operating and Maintenance Costs
Pond maintenance: 2% of invested pond capital
Non-pond maintenance: 6% of invested non-pond capital
Labor cost: $10,000/man-yr
Power: $100/HP-yr
Chemical: $lOO,000/yr
MINE DRAINAGE
Mine drainage is less than 10 percent of the total waste water
volume and is now partially treated with the process waste water.
Approximate estimates for treating any necessary residual mine
drainage water are $0.01 to 0.05/kkg of product produced.
362
-------
TABLE 39
LITHIUM MINERALS TREATO1T
PLANT AGE 15 YEARS
PLANT LOCATION
North Carolina
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/ KKG _££0.cjjntrgte
WASTE LOAD PARAMETERS
spodumene
(fcQ/ Vke of ^concentrate
Suspended Solids
RAW
WASTE
LOAD
100-
620
LEVEL
A
(MiN)
475,000
77,300
133,000
10,000
220,300
4.90
0.9
B
725,000
128,000
212,000
15,000
340,000
7.56
0.9
C
D
E
LEVEL DESCRIPTION:
A — Ponding of wasiewafer to remove suspended solids plus recycle of
process wasrewater
B — Level A plus segregation and treatment of additional wastewater streams plus
recycle of all process wastewater
All costs are cumulative.
363
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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 for non-acid mine drainage. 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 $0.17 to $0.28/kkg of
montmorillonite produced, see Table 42. Process and air scrubber
waste water treatment costs are summarized in Tables 40 and 41.
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.
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 (24,000 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 capital costs are estimated to be directly proportional to
the 0.9 exponential of size and directly proportional for
operating costs other than tcixes, insurance and capital recovery.
Cost Basis for Table 40
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: $0.0l/kwh
364
-------
TABLED
ATTAPULGITt TREAT1OT COSTS
PLANT SIZE
200,000
PLANT AGE 60 YEARS
KKG PER YEAR OF Attapulgite
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/ KKG
WASTE LOAD PARAMETERS
kg/ kkg
TSS
PH
RAW
WASTE
LOAD
LEVEL
A
(MIN)
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
39,100
300
50,500
0.23
0
_
D
E
LEVEL DESCRIPTION:
A — pond settling
B — A plus flocculating agents
C —• B plus recycle to process
All costs are cumulative.
365
-------
TABLE 41
IWITORILLONITC TREATMENT COSTS
PLANT SIZE
182,000
KKG
PLANT AGE 10 YEARS
PLANT LOCATION
PER YEAR OF Montmorlllonite
Georgia _
INVESTED CAPITAL COSTS'. $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 S M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG Mp^pmoft\\etnitt
WASTE LOAD PARAMETERS
(kg/kkg of monttnQrillJr
TSS
pH
RAW
WASTE
LOAD
ite)
LEVEL
A
(WIN)
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
All costs are cumulative.
366
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TABLED
fOTDRILLJONITE MINE WATER TFOTENT COSTS
PLANT SIZE
182,000
PLANT AGE 70 YEARS
KKR
PLANT LOCATION
PER YEAR OF Montmorillonfte
Georgia ^^
-
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/ KKG Montmorillonite
WASTE LOAD PARAMETERS
TSS, mg/liJ-er
RAW
WASTE
LOAD
LEVEL
A
(WIN)
0
0
0
0
0
0
20u—
5,000
B
60,000
15,800
12,300
3,000
32,300
0.17
zuu-
2,000
C
62,000
16,300
32,300
3,000
51,800
0.28
<50
D
E
LEVEL DESCRIPTION:
A — no treafmenf
B ~ pond setHing
C ~ B plus flocculaUng agents
All costs are cumulative.
367
-------
Labor rate assumed: $10,000/yr
Cost Basis for Table 41
Capital Costs
Pond cost, $/hectare (S/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: $10,000/yr
368
-------
KAOLIN
Kaolin 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 compounds 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 Table 13
for wet process kaolin.
The kaolin wet process subcategory consists of two facilities
having ages of 29 and 37 years. Age is not a cost variance
factor. The wet process kaolin operations are only located in
Georgia, hence not a variance. 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 directly proportional to the 0.9
exponential of size, and operating costs other than taxes,
insurance, and capital recovery are estimated to be directly
proportional to size.
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: $20,000/yr
Treatment chemicals
Lime: S22/kkg ($20/ton)
Flocculating agent: $2.2/kg ($1/lb)
Energy unit cost: $0.01/kwh
Maintenance: $10,000-11,000/yr
369
-------
TABLE 45
WET PROCESS KftOLIN TREATMT COSTS
PLANT SIZE 450,000
PLANT AGE 30 YEARS
KKG
PER YEAR OF Kaolin
PLANT LOCATION Georgia-South r.
ma
INVESTED CAPITAL COSTS: $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 a M (EXCLUDING
POV/ER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG of Kaolin
WASTE LOAD PARAMETERS
mg/1
TS5
Dissolved zinc
pH
RAW
WASTE
LOAD
1000C
100
LEVEL
A
(MIN)
447,000
49,200
85,000
5,000
139,200
0.31
50
0.25
6-9
B
463,000
51,800
112,000
5,000
168,800
0.38
25
0.25
6-9
C
487,000
55,600
90,000
5,000
152,200
0.34
0
0
—
D
E
LEVEL DESCRIPTION:
All costs are cumulative.
A — pond settling with lime treatment
B — A plus flocculating agents
C — pond settling and recycle 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.)
370
-------
BAIL CLAY
Those ball clay producers without wet air scrubbers do not have a
discharge, and no costs are presented. The costs for producers
using wet scrubbers are presented in Table 44. From the data
presented in Section VII and from the observations of the project
officer, the use of flocculants for the mine dewatering waste
water may be necessary. These costs are also presented in Table
44.
The ball clay subcategory has a range of facility ages from 15 to
56 years. A.ge has not been found to be a significant factor on
costs. Bali clay operations are located in the
Kentucky-Tennessee rural areas and hence location is not a
significant cost variance factor. 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.
Capital Costs Land 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: $20,000/yr
Treatment chemicals
Lime: $22/kkg ($20/ton) Flocculating agent: $2.2/kg
Maintenance: $10,000-1 1rOOO/yr
371
-------
TABLED
BALL CLAY TRETOff COSTS
PLANT SIZE
75,000
KKG
PER YEAR OF Ball Clay
PLANT AGE 30 YEARS
PLANT LOCATION Kentucky-Tennessee Region
INVESTED CAPITAL COSTS! $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 a M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AMD POWER
TOTAL ANNUAL COSTS $
COST/ k kg of Ball Clay
WASTE LOAD PARAMETERS
(kg/kkji of ball clay )
TS-S
pH
RAW
WASTE
LOAD
LEVEL
A
(WIN)
89,000
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
11,100
15,000
1,100
27,200
0.36
0
-
D
E
LEVEL DESCRIPTION:
All costs are cumulative.
A — pond settling
B — A plus flocculaHng agent
C — closed cycle operation (satisfactory only for scrubbers and cooling water)
372
-------
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 effluent and no waste water
treatment costs. Therefore, the only sufccategory 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. The waste
water pollutants are 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 45 for both
suspended solids and fluoride reductions. Successive treatments
for reducing suspended solids and fluorides are shown.
The 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. 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.
The feldspar wet process subcategory consists of 6 facilities
ranging in age from 3 to 26 years. Age is not a significant cost
variance factor because of similar raw waste loads. The feldspar
wet processing operations are located in southeastern and
northeastern states in rural areas. Other than hilly terrain
which has been accounted for, location has not been found to be a
significant cost variance factor. 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.
373
-------
TABLE'S
WET PROCESS FELDSPAR TREATCNT COSTS
PLANT SIZE 90,900
PLANT AGE 10 YEARS
KKG
PLANT LOCATION
PER YEAR OF Feldspar
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/ KKG Feldspar
WASTE LOAD PARAMETERS
(kg/ kkg of ore )
Suspended Solids
Fluoride
pH
RAW
WASTE
LOAD
2|%
0.22-
n.9
-------
Cost is estimated for capital directly proportional to the 0.9
power of size for treatments based on ponds and the 0.7th power
for treatments based on thickeners. Operating costs other than
taxest insurance and capital recovery are approximately directly
proportional to size.
Capital Costs
Pond cost, $/hectare ($/acre): 30,600 (12,500)
Settling pond area, hectares (acres): 0.1-0.8 (1-2)
Thickeners, filters, clarifiers: 0-$50,000
Solids handling eguipment: $40,000-50,000
Chemical metering equipment: 0-$50,OOQ
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
375
-------
KYANITE
Kyanite is produced at three locations. Two of the three
facilities have complete recycle of process water using settling
ponds. A summary of treatment technology costs is given in Table
46. 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 kkg of product.
The three facilities of this sufccategory range in age between 10
and 30 years. There is no significant treatment cost variance
due to this range. These facilities are in two southeastern
states in rural locations; location is not a significant cost
variance factor. 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 isr costs are approximately directly proportional to size.
Capital Costs
Pond cost, $/hectare ($/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: $1«,600/yr
Pipes: $3,300/yr
Energy unit cost: $0.01/kwh
Pumps: $1,200/yr
Labor: $3,000/yr
Maintenance: $16,900/yr
376
-------
TABU 16
TREATMENT COSTS
PLANT SIZE
45,000
PLANT AGE 15 YEARS
KKG
PER YEAR OF Kyanite
PLANT LOCATION South eastern U.S.
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/ KKG Of Kyanite
WASTE LOAD PARAMETERS
(kg/ kkg
Tailings
TSS-
pH
RAW
WASTE
LOAD
5500
LEVEL
A
(M1N)
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
All costs are cumulative.
Note: Most of the above cost at A level (65-70%) is the cost of removal and disposal
of solids from ponds,
377
-------
MAGNESITE
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-pereolation 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 the 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.
Shale and common clay 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. 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 ty location. 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 produced at two facilities in the U.S. One facility
with a dry process uses wet scrubbers. The waste water is ponded
to remove suspended solids and then discharged. Waste water
treatment costs were calculated to be $O.U8/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:
capital: $9,000
annual capital recovery:$1,470
annual operating and maintenance, excluding power and energy:
$630
annual power and energy: $1,300
total annual cost:$3,400
378
-------
Aplite is produced by two facilities which are 17 and U1 years
old. Age has not been found to be a significant cost variance
factor. Both aplite facilities are located in Virginia and,
therefore, location is not a significant cost variance factor.
The 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.
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 0 & M cost: $1,900/yr
Maintenance:$4,500-16,500/yr
379
-------
TALC MINERALS GROUP
Suspended solids are the 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. Mines and processing facilities may
be either wet or dry. Dry operations have no treatment costs.
Mine Water
Pain 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 $1.38/kkg talc produced. The large figure
represents extremely small mines that would be mined in
conjunction with other larger mines by a company.
Wet processes are conducted in both the eastern and western U.S.
Waste water from Eastern wet processes comes from process
operations and/or scrubber water. The usual method of treating
the effluent is to adjust pH by the addition of lime, followed by
pond settling. Treatment options, costs and resultant effluent
quality are summarized in Table 47. Facilities not requiring
lime treatment would have somewhat lower costs than those given.
Wet process facilities in the Western 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. The required evaporation pond size in this
case is similar to that needed for good settling pond
performance.
Facilities in the talc minerals group range from 2 to 70 years of
age. However, the heavy media separation and flotation
subcategory consists of only three facilities of 10 to 30 years
of age. This is not a significant treatment cost variance
factor. 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. 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 can be estimated to be directly proportional
to the exponent of 0.8 to size, and operating costs other than
capital recovery, taxes and insurance are approximately
proportional to size.
Capital Costs
Land cost, $/hectare ($/acre): 24,500 (10,000)
380
-------
TABLE 47
WET PR3CESS TALC MINERALS TREATMENT COSTS
PLANT SIZE
45,000
KKG
PER YEAR OF tafc minerals
PLANT AGE 25 YEARS
PLANT LOCATION Eastern 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/ kkg of products
WASTE LOAD PARAMETERS
{kg/ kk§ of products )
TSS
pH
RAW
WASTE
LOAD
800 to
1800
LEVEL
A
(WIN)
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
All costs are cumulative.
381
-------
Mine pumpout, settling pond area, hectares (acres):
up to 0«t» (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
382
-------
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 kkg 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
There are three garnet producers ranging in age from 40 to
50 years. Age has not been found to be a significant cost
variance factor. 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. The garnet producers range in size from
5,100 kkg/yr to an estimated 86,200 kkg/yr (5,600-95,000
tons/yr). The differences in size are so great that there is no
representative facility for this sufccategory. Due to process and
size differences, treatment costs must be calculated on an
individual basis.
383
-------
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. 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 tetter facilities. All facilities are currently employing
settling and neutralization.
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 that represents 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 watering of 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.
384
-------
SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH THE
APPLICATION OF THE
BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE
The effluent limitations which must be achieved by July 1, 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 minerals for the
construction industry, this level of technology was based on the
average of the test existing performance by facilities of various
sizes, ages, and processes within each of the industry's
subcategories. 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) select manufacturing process controls;
(b) recycle and alternative uses of water; and
(c) recovery and/or reuse of some waste water constituents.
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).
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. Storage pile and plant area runoff are not
process generated waste water and are considered separately. All
process generated waste water effluents are limited to the pH
range of 6.0 to 9.0 unless otherwise specified.
385
-------
Where sufficient data was available a statistical analysis of the
data was performed to determine a monthly and a daily maximum. A
detailed analysis of the daily TSS maximum and the monthly TSS
maximum at a 99 percent level of confidence for phosphate slime
ponds and kaolin ponds indicates that a TSS ratio of the maximum
monthly average to the long term average of 2.0 is representative
of settling pond treatment systems and of the daily maximum to
the long term average of 4.0. It is judged that these ratios are
also valid for the other parameters controlled in this category.
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.
This approach was not used for most subcategories of mine
dewatering. Instead the data within each subcategory was
individually assessed.
Non-contact cooling water is only occasionally used in this
industry. No adverse environmental impact has been found for
such discharges. Therefore, no effluent limitation of
non-contact cooling water is recommended until general guidelines
are issued covering this. In the interim water guality imposed
limitations can meet with any existing problems.
A mine is an area of land, surface or underground, actively used
for or resulting from the extraction of a mineral from natural
depostis. Mine drainage is any water drained, pumped or siphoned
from a mine. Mine dewatering waste water is that portion of mine
drainage that is pumped, drained or otherwise removed through the
direct action of the mine operator in order that the mining
operation may continue. Pit pumpage of ground water, seepage and
precipitation or surface runoff entering the active mine workings
is an example of mine dewatering. The pH of mine dewatering
discharges are limited to between 6.6 to 9.0. This pH range is
not meant to suspercede state water quality criteria for
receiving waters naturally have a pH outside of the 6.0 to 9.0
range. Discharges of non-process water such as mine water with a
pH less than 6.0 may be discharged at a lower pH only if this pH
is within the EPA approved state water quality criteria for pH
for the receiving stream. This situation can arise in swamps.
Untreated overflow may be discharged from process waste water or
mine dewatering impoundments without limitation if the
impoundments are designed, constructed and operated to treat all
process generated waste water or mine drainage and surface runoff
into the impoundments resulting from a 10-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 the limit
specified as representing the best practicable control technology
currently available. To preclude unfavorable water balance
conditions resulting from precipitation and runoff in connection
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with tailing impoundments, diversion ditching should be
constructed to prevent natural drainage or runoff from mingling
with process waste water or mine dewatering waste water,
WASTE WATER GUIDELINES AND LIMITATIONS
DIMENSION STONE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This is
alternative C, ponding and recycle of process water. At least
four facilities (3008, 3010, 3017, 3018) representing all the
major types of stone presently achieve no discharge of process
generated waste water.
Mine dewatering shall not exceed 30 mg/1 TSS at any time. This
quality of water is currently attained by dimension stone
quarries as indicated by the data in Section VII. Furthermore,
this quality of water is attained by crushed stone quarries which
although nearly identical to dimension stone quarries are dirtier
because of constant truck haulage. In any case where the water
would exceed the limit, pit pumpout could be temporarily ceased
until the water clears. Alternately flocculatants could be used
on an intermittent basis or a settling pond could be
inexpensively built. Poor quarry practice such as allowing muddy
surface drainage to enter the quarry or frequent movement of
equipment through flooded areas are the only expected causes of
the limit being exceeded.
CRUSHED STONE (DRY)
Best practicable control technology currently available is no
discharge of process generated generated waste water pollutants
because no process water is used.
CRUSHED STONE (WET)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants.
This technology represents alternatives C and, if necessary D.
To implement this technology at facilities not already using the
recommended control techniques would require the installation of
pumps and associated recycle equipment and possible expansion of
treatment pond facilities. Approximately one third of the
facilities studied presently use the recommended technology.
CRUSHED STONE (FLOTATION PROCESS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. Facility
1975 is currently meeting this requirement. Facility 3069 is
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recycling about 70 percent of the process water to the washing
mills. At facilities not totally recycling, flotation cell water
can be recycled as wash water. Excess flotation cell water can
be used as cooling water make-up and for dust control purposes
which can consume large quantities of water.
CRUSHED STONE (MINE DEWATERING)
Mine dewatering shall not exceed 30 mg/1 TSS at any time. This
quality of water is currently attained by most crushed stone
quarries as indicated by the data in Section VII. In cases where
this limitation is exceeded, the causes can be attributed to the
following. The settling area is often a small mined depression
on the quarry floor referred to as a sump. It is almost never
designed to efficiently remove suspended solids, and this could
be too small for sufficient settling time. Most often the pump
inlet is not placed in this sump to allow for maximum settling
time. These deficiencies are usually compensated by the
excellent purity of the ground water and the inert nature of the
hard rock versus clay material. Intrusion of muddy surface
drainage into the quarry and constant equipment traffic in
flooded areas are poor practices that will overload the sump.
However, temporary halting pit pumpout to allow the water to
clear, use of flocculants on an intermittent basis, or
construction of an inexpensive settling pond will also cure muddy
quarry water problems.
CONSTRUCTION SAND AND GRAVEL (DRY)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process water is used.
CONSTRUCTION SAND AND GRAVEL (WET)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This can
be economically achieved by use of alternatives C, D or G which
involve the ponding and/or recycle of all process waste water.
More than half the subcategory is presently achieving no
discharge.
This subcategory includes the dredging of non-navigable waters
that are closed (wet pits), that is ponds entirely owned or
leased from the pond owner. These frequently are flooded dry
pits. Process water should fce recycled to these pits.
Overflow from these wet pits caused by rainfall and ground water
infiltration is classified as mine dewatering. Runoff from areas
outside the mine and plant should be excluded from the pit.
CONSTURCTION SANE AND GRAVEL
(MINE DEWATERING)
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Mine dewatering shall not exceed 30 mg/1 TSS at any time. Except
for emergency pumpinq after flooding, mine dewatering is unusual
in this sufccateqory. Pits experiencing ground water flooding are
usually allowed to fill and the deposit is dredged. This is in
contrast tc stone quarries where dreding is not possible for hard
rock. In cases where it might be practiced, a sump arrangement
like that for stone quaries would not be satisfactory and a well
designed settling pond would be necessary. This is because sand
deposits frequently contain clay. If good mining techniques are
practiced a relatively constant raw waste load should result and
pond upsets should not occur. The limitation if not then
attained can be met by use of flocculants. This technology is
being successfully practiced in many subcategories including sand
and gravel process water, crushed stone and clays. In some cases
mine water is treated in the process waste water pond system.
This practice is allowed if the process facility uses recycled
water.
CONSTRUCTION SAND AND GRAVEL (DREDGING WITH LAND PROCESSING)
This subcategory covers dredging in navigable waters. The best
practicable control technology currently available is no
discharge of process generated waste water pollutants from the
land based operations where the process water intake does not
originate from the dredge pump. This limit can be achieved by
ponding and/or recycle of all non-dredge pumped process waste
water. More than half this sufccategory has achieved this level
of technology for on-land treatment. No limits are proposed for
dredge pumpage water pending further investigation of this
subcategory. Discharges from dredges are covered under section
404 of the Act, "Permits for Dredged or Fill Material."
INDUSTRIAL SAND (DRY PROCESS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the recycle of air pollution control scrubber
water after flocculation and settling. There is no water used in
the processing of this mineral. This technology is employed by
at least one facility (1107) in this subcategory.
INDUSTRIAL SAND (WET PROCESS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology (alternative B or C) involves settling of suspended
solids by means of mechanical equipment and/or ponds and complete
recycle of process water. Three (1019, 1989 and 3066) of the
four facilities surveyed presently utilize the recommended
technologies.
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INDUSTRIAL SAND (ACID AND ALKALI FLOTATION PROCESS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology (alternative B) involves the settling of suspended
solids in ponds using flocculants where necessary, adjustment of
pH where necessary and/or recycle of process water. Four (1101,
1103, 1019 and 1980) of the five facilities studied are currently
meeting the recommended limitation by utilizing these
technologies.
INDUSTRIAL SAND (HF FLOTATION PROCESS)
The best practicable control technology currently available is:
Effluent Limitation
kg/kkg
Effluent (Ib/lOOO Ib) of product
Characteristic Monthly Average Daily Maximum
TSS 0.023 O.OU6
fluoride 0.003 0.006
The above limitations were based on the average performance of
the only facility (5980) in this subcategory. A maximum 914
1/kkg discharge flow was used as reported by the company. A TSS
of 25 mg/1 and F of 3.5 mg/1 were used for the monthly average.
This technology (alternative A) involves thickening, ponding to
settle suspended solids, pH adjustment and partial recycle of
process water.
INDUSTRIAL SAND (MINE DEWATERING)
Industrial sand mining is essentially identical to that for sand
and gravel. Hence the same limitation is required: TSS shall
not exceed 30 mg/1 at any time.
GYPSUM (DRY)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process water is used. The one facility using a wet air scrubber
currently recycles this water.
GYPSUM (HEAVY MEDIA SEPARATION)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the recovery of the heavy media, settling of
suspended solids, and total recycle of process water. This
technology is used at both facilities in this subcategory.
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GYPSUM (MINE DEWATERING)
Mine debatering shall not exceed 30 mq/1 TSS at any time. The
data in Section VII shows that most mines can achieve this
limitation. Little or no treatment is practiced. Gypsum mining
is very similar to crushed stone mining.
ASPHALTIC MINERALS (BITUMINOUS LIMESTONE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process waste water is used.
ASPHALTIC MINERALS (OIL IMPREGNATED DIATOMITE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. The
technology involves the recycle of scrubber water. There is no
water used in the processing of this material. The one facility
in this subcategory (5510) presently uses the recommended
technology.
ASPHALTIC MINERALS (GILSONITE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology (alternative B) involves ponding, settling and partial
recycle of water. There is only one facility (5511) in this
subcategory and it presently uses the recommended technologies.
ASBESTOS (DRY PROCESS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
water is used in the process.
ASBESTOS (WET)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. The
technology involves the total impoundment of all process waste
waters. The techniques described are currently used by the only
facility (1060) in this subcategory.
ASBESTOS (MINE DEWATERING)
Mine dewatering shall not exceed 30 mg/1 TSS at any time. Only
one facility is known to be dewatering at the present time, and
the data in Section VII indicates that it can achieve the
limitation. No problem is anticipated if other cases arise
because of the hard rock nature of the deposit.
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WOLLASTCNITE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process water is used. Mine dewatering shall not exceed 30 mg/1
TSS at any time. There is no known mine dewatering, but because
of the hard rock nature of the deposit, there should be no
problem of achieving the limitation.
LIGHTWEIGHT AGGREGATE MINERALS (PERLITE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process water is used. Mine dewatering shall not exceed 30 mg/1
TSS at any time. Mine dewatering was not encountered, but it is
not expected to present a problem since colloidal clays are not
present.
LIGHTWEIGHT AGGREGATE MINERALS (PUMICE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process water is used. Mine dewatering shall not exceed 30 mg/1
TSS at any time. Mine dewatering was not encountered, but it is
not expected to present a problem since colloidal clays are not
present.
LIGHTWEIGHT AGGREGATE MINERALS (VERMICULITE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology (alternative A) involves the ponding to settle
suspended solids, clarification with flocculants if needed, and
recycle of water to process. The two major facilities producing
vermiculite (5506 and 5507) presently use the recommended
technologies. Mine dewatering shall not exceed 30 mg/1 TSS at
any time. Mine dewatering was not encountered, but it is not
expected to present a problem since colloidal clays are not
present.
MICA AND SERICITE (DRY PROCESS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process water is used.
MICA (WET GRINDING PROCESS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the settling of suspended solids and recycle
of clarified water. One of the three facilities in this
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subcategory (2059) utilizes the recommended technologies.
Another (2055) recycles part of the process waste water.
MICA (WET EENEFICIATION PROCESS, EITHER NON-CLAY OR
GENERAL PURPOSE CLAY BY-PRODUCT)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the settling of suspended solids in ponds and
recycle of process water (alternative C or E). Four of the five
facilities in this subcategory (2050, 2051, 2053 and 2058) are
presently using the recommended technologies. The fifth (2054)
was in the process of converting to total recycle at the time of
the study.
MICA (WET EENEFICIATION PROCESS, CERAMIC GRADE CLAY BY-PRODUCT)
The best practicable control technology currently available is:
Effluent Limitation
kg/kkg of product (lb/1000 Ib)
Effluent Characteristic Monthly Average Daily Maximum
TSS 1.5 3.0
The best available technology economically achievable is also no
discharge of process generated waste water pollutants. The above
limitations are based on the performance of two facilities (2052
and 2057). The technology (alternative B or D) involves settling
of suspended solids in ponds and lime treatment for pH adjustment
prior to discharge.
MICA AND SERECITE (MINE DEWATERING)
Mine dewatering shall not exceed 30 mg/1 TSS at any time. One
facility dewaters the mine into the process waste water pond in
which flocculant is added. This water is planned to be
completely recycled back to the plant (2054). Other mine
dewatering is not known. In the event of mine dewatering, this
water can be treated with flocculants on an intermittent basis to
the above limitation.
BARITE (DRY PRODUCTION SUECATEGORY
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because no
process water is used.
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BARITE (WET-LOG WASHING AND JIGGING AND FLOTATION)
The best practicable control technology currently available is no
discharge of process waste water pollutants. There is no
discharge of process waste water pollutants during normal
operating conditions. This technology (alternative B for washing
and C for flotation) involves the containment of process waste
water, settling of suspended solids, and recycle of process water
during normal operating conditions. Where there is a discharge
during periods of heavy rainfall, settling of suspended solids by
ponding, flocculation, coagulation or other methods may be
necessary. Tailings pond storm overflow shall not exceed 30 mg/1
TSS. Four facilities in these sufccategories in the same net
precipitation geographical location are currently achieving this
limitation.
BARITE (MINE DEWATERING)
Non acidic mine dewatering shall not exceed 35 mg/1 TSS. The
following limits apply to acid mine dewatering:
Effluent Limitation
mq/1
Effluent Characteristic Monthly Average Daily Maximum
TSS 35 70
Total Fe 3.5 7.0
Mine dewatering is rarely practiced in barite mining. Where the
mine water is non-acidic the limitation can be met by the
intermittenent use of flocculants. There is one underground mine
experiencing acid mine drainage.
FLUORSPAR (HMS)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology (alternative B) involves the impoundment of process
water and total recycle. Five of the six facilities (2004, 2005,
2006, 2008 and 2009) studied are presently utilizing the
recommended technologies (alternative B) .
FLUOPSPAB (FLOTATION)
The best practicable control technology currently available is:
Effluent Limitation
kg/kkg of product (lbs/1000 Ib)
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.6 1.2
dissolved fluoride 0.2 O.t
39*
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The above limitations are based on the anticipated performance of
treatment systems currently being installed at two facilities
(facilities 2000 and 2001). They represent concentrations of
approximately 50 mg/1 for TSS and 20 mg/1 for F. This technology
(alternative B) involves the ponding in series and flocculation
to reduce suspended solids and fluoride prior to discharge. An
alternative technology is ponding and evaporation where possible.
To implement this technology at facilities not already using the
recommended control techniques would require the installation of
ponds in series and flocculant addition facilities. Two
facilities are presently installing the recommended technologies.
FLUORSPAR (DRYING AND PELLETIZING)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants because
there is no process water.
MINE DEWATERING
Mine dewatering shall meet 30 mg/1 TSS as a daily maximum. This
level is achieved by most mines as indicated by the data in
Section VII. Settling ponds will be required by those operations
that do not meet the limitations.
SALINES FROM BRINE LAKES (SEARLES LAKE)
The best practicable control technology currently available is no
net discharge of process waste water pollutants. These
operations return the dep .eted brines and liquor to the brine
source with no additional pollutants. The two facilities in this
production subcategory are presently using the recommended
control technologies.
SALINES FROM BRINE LAKES (GREAT SALT LAKE)
The best practicable control technology currently available is no
net discharge of process waste water pollutants. The only
operation meets this requirement by the return of depleted brines
and liquor to the lakes with no additional pollutants.
SALINES FROM BRINE LAKES (SILVER PEAK)
The best practicable control technology currently available is no
net discharge of process waste water pollutants. This involves
the return of depleted brines and liquor to the brine source.
The only facility in this production subcategory is presently
using the recommended control technology, and there is no
discharge to navigable waters.
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BORAX
The best practicable control technology currently available is no
discharge of process waste water pollutants. This technology
(alternative A) involves the use of lined evaporation ponds. The
only facility in this subcategory presently uses the recommended
technology.
POTASH
The best practicable control technology currently available is no
discharge of process waste water pollutants. This technology
(alternative A) involves the use of evaporation ponds to contain
process water. All facilities in this subcategory are presently
using the recommended technology.
TRONA
The best practicable control technology currently available is no
discharge of process waste water and mine dewatering pollutants.
This technology (alternative E) involves the total impoundment
and evaporation of all process waste water and mine water. All
facilities either plan to or currently use this technology to
dispose of waste water.
SODIUM SULFATE (BBINE WELL)
The best practicable control technology currently available is no
discharge of process waste water pollutants. This technology
involves the total impoundment and evaporation of all process
waste water. The two facilities representing this production
subcategory are presently using the recommended control
technologies.
ROCK SALT
The best practicable control technology currently available is:
Effluent Limitation
kg/kkg of product
(lb/1000 Ib)
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.02 0.04
The above limitations are based on the performance currently
achieved by at least three facilities. Mine dewatering is
included in the above limitations. This technology (alternative
B or C) is the control of casual water with good water management
practices and settling where required. To implement this
technology at facilities not already using the recommended
control technigues would reguire better water management
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practices and the installation of adequate settling facilities
where required.
PHOSPHATE ROCK
The best practicable control technology currently available is:
Effluent Limitation
Effluent Monthly Average Daily Maximum
Characteristic
TSS 30 mg/1 60 mg/1
These limits apply to the quantity of water used in the flotation
circuits which cannot be economically recycled, mine water,
rainfall and runoff. These latter two water sources necessitate
using a concentration rather than a mass unit because they are
production independent. These limitations represent alternative
B.
There shall be no discharge of process generated waste water from
floor washdowns, slurry transport water, equipment washing, ore
desliming water, pump seal water, and air emission scrubber
water. This can fce achieved by total recycle. However, since it
could be physically and economically prohibitive to separate
these waters from flotation cell water and mine water, this
condition can be met by using recycled water and using fresh
water only as necessary to maintain a water balance.
The above limitations were based on the performance achieved at
most of existing slime ponds as shown in Section VII. A
statistical analysis was performed by fitting a three parameter
log normal distribution to the data. Once the optimum value for
Tau was found, the distribution was then extrapolated to
determine the level of treatment presently achievable at a
confidence level of 99 percent for the daily and average monthly
values of TSS. It was judged that the average of all these
values could not be used since the factors controlling the
variability of effluent quality for the slime pond are beyond the
practical control of the facility operator. These factors
include wind, temperature, and aquatic growth and activity. This
last point is demonstrated by the fact that volatile suspended
solids comprised the majority of the TSS of the final effluents.
The limitations reflect the degree of treatment achievable by
properly constructed and maintained slime ponds. Some of the
facilities not achieving the limits had insufficient data to be
reliable (less than 12 data points). The two worst discharges
were observed by the project officer to suffer considerable
erosion of the earthen discharge ditch walls at points prior to
the sample points. Other problems noted were incorrect sampling
locations and procedures. At one facility the sample point
included all untreated facility runoff in addition to the pond
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discharge. At another the sampler consistently stirred up
sediment in the pipe bottom, and consequently the reported levels
of TSS were incorrectly high. With proper operation all process
ponds can achieve the standards 100 percent of the time.
If unpredictable pond or process upsets do occur, the present use
of decant towers by the industry allows the facility operator to
cease the discharge for a sufficient length of time in order that
the suspended solids settle and be in compliance with the
discharge limitations.
Fluoride and phosphorus will not be regulated for the following
reasons. First the existing treatments are operated to remove
only suspended solids. The levels of fluoride appear to be
related in part to the well water used in the flotation process.
In addition the present fluoride concentrations are far below the
practicable level of teatment used by related industries. It is
expected that a significant portion of the phosphorus is in the
form of a suspended solid and that removal of TSS will effect
removal of phosphorus.
Although observed concentrations of radium 226 in effluents are
generally below 3 pCi/1, the potential exists for effluent
concentrations of this radionuclide to substantially increase.
These increases are brought about primarily by higher suspended
solid levels than allowed in the effluent or the introduction of
acid to slime or effluents. All facilities sampled currently
meet this radium 226 level. Therefore, this parameter will not
be regulated at this time.
Most of the Florida, North Carolina and Tennessee facilities on
which the gui "elines were based are presently achieving the
recommended limitations using these technologies. All Western
operations do or will shortly recycle all such waters.
SULFUR (FRASCH PROCESS, ANHYDRITE)
The best practicable control technology currently available is no
discharge of process waste water pollutants. Mine dewatering is
included in the above limitations. This technology involves the
chemical treatment and recycle of process water. Both facilities
in this subcategory are using these technologies.
SULFUP (FRASCH PROCESS, SALT DOME OPERATIONS)
The best practicable control technology currently available is:
Effluent Limitation
Effluent mg/1
Characteristic Monthly Average Daily Maximum
TSS 50 100
sulfide 1 2
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The above limitations are based on the current performance
(alternative C, C, E or F) of the 9 facilities in this
subcategory. The quantity of water used in this subcategory is
independent of the quantity of product. Therefore, effluent
limitations based on quantity of pollutant per unit of production
are not practical. Mine dewatering (bleed water) is included in
the above limitations.
For facilities located in marshes that have insufficient land to
build large enough oxidation ponds to achieve the above numbers
the following limits apply.
Effluent Limitation
mq/1.
Effluent Monthly Daily
Charac teristjc Average Maximum
TSS 50 100
Sulfide 5 10
This technology involves oxidation of sulfides and the use of
ponds to reduce suspended solids. If oxidation ditches are used
by adding water to utilize its dissolved oxygen content, the TSS
limits are to be applied on a net basis. Six of the nine
facilities are presently using the recommended technologies.
Well seal water is not regulated at this time. It will be
required by the best available technology economically achievable
to be incorporated into the bleed water treatment system.
SULFUR (FRASCH PROCESS - OFF-SHORE SALT DOME OPERATIONS)
No limits on off-shore operations are proposed at this time
pending further investigation. Off-shore operations are defined
as those open water operations sufficiently distant from land
that the well bleed water wastes cannot be pumped ashore due to
economic infeasiblity for aeration pond treatment,
MINERAL PIGMENTS (IRON OXIDES)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the ponding and recycle of process waste
water. This technology (alternative B) is presently being
demonstrated by at least one major processor using process water.
This facility (3022) uses a large pond common to the treatment of
waste water from another larger production volume product and the
discharge from the pond is attributable to the larger volume
product. Two of the three facilities studied use no process
water. This technology involves the ponding and recycle of
process water when used. Mine dewatering should not exceed 30
mq/1 TSS based on the data from other subcategories.
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LITHIUM MINEBALS (SPODUMENE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants
(alternative A). There are only two spodumene facilities in
operation. Facility U009 currently operates on total recycle.
There is some dam seepage and heavy storm overflow. Facility
4001 is constructing an impoundment to achieve total recycle.
Tailings dam seepage and tailings pond storm overflow shall not
exceed 50 mg/1 TSS. This is to be measured at the point of
discharge. The process waste water limitations apply to the
recovery of other minerals in the spodumene ore.
Mine dewatering shall not exceed 35 mg/1 TSS at any time. The
mine water at the two mines appears to contain colloidal clay
which will require periodic use of flocculants. Treatment to
this level is successfully demonstrated by other subcategories
including coal and fuller* s earth.
BENTONITE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants, because no
process water is used. Mine dewatering shall not exceed 35 mg/1
TSS at any time. No mine dewatering was found in this study.
Where mine dewatering does occur the use of settling ponds or
careful pumping of mine water to avoid turbulence is necessary.
As noted in Section III the difference between bentonite and
fullers' eartv is more of commercial use than geological
significance. Thus the technologies used for fullers* earth are
also applicable. The use of flocculants on an intermittent basis
will be necessary if colloidal clays are present.
FIRE CLAY
The best practicable control technology currently available is
no discharge of process generated waste water pollutants since no
process water is used. Mine dewatering for non-acidic waters
shall not exceed 35 mg/1 TSS at any time. The data indicates
that many mines can meet the limitation without treatment or
additional treatment. In those cases where the limitation is
exceeded the use of flocculants on an intermittent basis will be
necessary. This technology has been successfully demonstrated in
many other subcategories including fullers' earth. Acid mine
drainage must meet the following limitations:
Effluent Characteristic
Monthly Average Daily Maximum
TSS, mgl 35 70
UOO
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Total Fe, mg/1 3.5 7.0
These limitations reflect the technology employed by the coal
category. The limitations are directly applicable because fire
clay is frequently associated with coal.
FULLER'S EARTH (ATTAPULGITE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
condition is currently met by four facilities (3058, 3060, 3C88
and 3089). This technology (alternative C) involves the 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. Mine dewatering shall not exceed 35 mg/1 at any
time. The data in Section VII indicates that this can be
achieved by current practice.
FULLER'S EARTH (MONTMORILLONITE)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. Two
facilities studied (3059-3073) presently use the recommended
technology. Mine dewatering shall not exceed 35 mg/1 TSS at any
time. The data in Section VII indicates that montmorillonite
mines will have to occassionally use flocculation to meet the
limitation (alternative C). Mine 3059 has successfully
demonstrated flocculation and removal of TSS to very low levels
for one of the highest concentrations of TSS in mine water that
was allowed extensive time to settle. Successful use of
flocculants at coal and other clay mines further demonstrate the
technical feasibility.
KAOLIN (DFY PROCESSING)
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.
KAOLIN (WET PROCESSING)
The best practicable control technology currently available is:
Effluent Limitation
Effluent Characteristic Monthly Average Daily Maximum
TSS, mg/1 <*5 90
Turbidity, JTU or FTU 50 100
Zinc, mg/1 0.25 0.50
The above limitations were based on a statistical analysis of the
performance attainable by the two facilities (3021 and 3025). In
401
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addition other Georgia kaolin producers have claimed that these
limits are achievable. The technology involved (alternative B)
is pH adjustment and flocculation. Some facilities flocculate
first at a low pH and then pH adjust. Zinc precipitation by lime
addition is necessary where zinc compounds are used to bleach the
kaolin.
KAOLIN (MINE DEWATERING)
Mine dewatering from mines not pumping the ore as a slurry to the
processing facility shall not exceed 35 mg/1 TSS at any time.
The data in Section VII indicates that this is currently being
achieved.
The following limits apply to mine dewatering from mines pumping
the ore as a slurry to the processing facility.
Effluent Limitation
Effluent Characteristic Monthly Average Daily Maximum
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.
BALL CLAY (WET PROCESSING)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology (alternative C) involves 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 and recycle.
BAIL CLAY (DPY 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, the best practicable control technology currently
available is no discharge of process generated waste water
pollutants.
BALL CLAY (MINE DEWATERING)
Mine dewatering shall not exceed 35 mg/1 TSS at any time. The
data is Section VII indicates that the intermittent use of
flocculants will be necessary to achieve the limitations. This
technology is practiced in other subcategories.
FELDSPAR (FLOTATION)
402
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The best practicable control technology currently available is;
Effluent Limitation
kq/kkq (lb/1000 Ib) of ore processed
Effluent Characteristic Monthly Average Daily Maximum
TSS
Fluoride
0.60
0.175
1.2
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. This technology
(alternative C) involves the recycle of part of the process waste
water for washing purposes, then neutralization and settling 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. A concentration of UO mg/1 F can be achieved
for this waste stream. This waste stream can then be combined
with the remaining 75 percent of the non-HF contaminated water.
FELDSPAR (NON-FLOTATION)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology is the natural evaporation of dust control water used
in the process. This is the only water used in the process.
FELDSPAR (MINE DEWATERING)
Mine dewatering shall not exceed 30 mg/1 TSS at any time.
Feldspar mining is a hard rock operation and the suspended solids
appear to settle rapidly as for crushed stone operations. Mine
runoff rather than dewatering is the normal method of water
escape.
KYANITE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the recycle of process water from settling
ponds. Facility 3015 is currently achieving the limitation.
Facility 3028 operates on total recycle. However, excessive
runoff results in periodic discharges. This can be rectified by
exclusion of excess runoff from the process waste water pond.
Mine dewatering shall not exceed 35 mg/1 TSS at any time. Mine
dewatering was not practiced at the mines inspected.
403
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MAGNESITE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves 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
The best practicable control technology currently available is no
discharge of process generated waste water pollutants, since no
water is used. Mine dewatering shall meet 35 mg/1 TSS at all
times. This technology involves settling or the use of
flocculants on an intermittent basis.
APLITE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the ponding of process waste water to settle
solids and recycle of water. This technology is currently
employed at facility 3016. Mine dewatering shall not exceed 35
mg/1 TSS at any time. Mine dewatering was not practiced at the
mines inspected.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE (DRY PROCESS)
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)
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the total impoundment or recycle of process
waste water. All facilities in this subcategory currently employ
the recommended control technology.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE (HEAVY MEDIA
AND FLOTATION)
The best practicable control technology currently available is:
Effluent Limitation
kg/Kkg (lb/1000 Ib) of product
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.5 1.0
404
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The above limitations were based on the performance achievable by
three facilities (2032, 2033 and 20M4) and a fourth facility
(2031) achieving no discharge of process waste water. This
technolocry (alternative A) involves pH adjustment of the
flotation tailings, gravity settling and clarification. All
facilities in this subcategory are presently using the
recommended technologies.
TALC, STEATITE, SOAPSTONE, FYROPHYYLLITE (MINE DEWATERING)
Mine dewatering shall not exceed 30 mg/1 TSS at any time. The
above limitations are based on the data from 8 mines given in
Section VII.
GARNET
The best practicable control technology currently available is:
Effluent Characteristic
Effluent Limitation
Monthly Average Daily Maximum
TSS, mg/1
30
60
This technology involves pH adjustment, where necessary, and
settling of suspended solids. The two facilities accounting for
over 80 percent of the U.S. production are presently using the
recommended technologies.
TRIPOLI
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. No
process waste water is used in the dry processes. One operation
uses a small guantity of water for dust collection. This water
is treated with a flocculant and settled. This water should be
of suitable quality to recycle. Alternately dry dust collection
technigues can be employed.
Mine dewatering shall not exceed 30 mg/1 TSS at any time.
Tripoli mine dewatering was not found in this study. Tripoli is
not associated with colloidal clays; hence the limitations should
be able to be achieved by settling.
DIATOMITE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the use of evaporation ponds and/or recycle
of process water. Three facilities (550U, 5505 and 5500) of this
subcategory representing approximately half the U.S. production
utilize this recommended technology.
U05
-------
Mine dewatering shall not exceed 30 mg/1 TSS at any time. Mine
dewatering was not found in this study. Diatomite is not
associated with colloidal clays; hence the limitations should be
able to be achieved by settling.
GRAPHITE
The best practicable control technology currently available is:
Effluent Limitation
Effluent Characteristic Monthly Average Daily Maximum
TSS, mg/1 10 20
Total Iron, mg/1 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 dewatering are included.
Concentration was used because of the variable flow of mine
water. This technology involves neutralization of mine water and
pond settling of both mine and process waste water.
JADE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the settling and evaporation of the small
volume (less than 100 gallons per day) of waste water. The only
major U.S. jade production facility presently employs these
techniques. The mine is only infrequently operated, in fact only
a few days in the last three years. Mine pumpout is therefore
not regulated.
NOVACULITE
The best practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology involves the total recycle of process scrubber water.
There is only one facility in the U.S. It is presently using
this technology. Mine dewatering is not practiced.
406
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SECTION X
EFFLUENT SEDUCTION ATTAINABLE THROUGH THE
APPLICATION OF THE BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE
The effluent limitations which must be achieved by July 1, 1983
are based on the degree of effluent reduction attainable through
the application of the best available technology economically
achievable. For the mining of minerals for the construction
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.
The following factors were taken into consideration in
determining the best available technology economically
achievable:
(1) the age of the equipment and facilities involved;
(2) the process employed;
(3) the engineering aspects of the application of various types
of control techniques;
(U) process changes;
(5) the 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, the 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
(2) water conservation
(3) waste stream segregation
(1) water reuse
(5) cascading water uses
(6) by-product recovery
(7) reuse of waste water constituents
(8) waste treatment
(9) good housekeeping
(10) preventive maintenance
(11) quality control (raw material, product, effluent)
(12) monitoring and alarm systems.
407
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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.
The reguirements for mine dewatering waste water are the same as
for the best practicable control technology currently available.
The pH limitation for all process generated and mine dewatering
waste waters is to be between 6.0 and 9.0.
Untreated overflow may be discharged from process waste water or
mine dewatering impoundments without limitation if the
impoundments are designed, constructed and operated to treat all
process generated waste water or mine drainage and surface runoff
into the impoundments resulting from a 10-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 the
limitation specified as representing the best available
technology economically achievable. 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 dewatering waste water.
The following industry subcategories were reguired to achieve no
discharge of process generated waste water pollutants to
navigable waters based on the best practicable control technology
currently available:
dimension stone
crushed stone (dry)
crushed stone (wet)
crushed stone (flotation)
construction sand and gravel (dry)
construction sand and gravel (wet)
construction sand and gravel (dredging with land
processing)
industrial sand (dry)
industrial sand (wet)
industrial sand (acid and alkaline flotation)
gypsum
bituminous limestone
oil impregnated diatomite
U08
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gilsonite
asbestos
wollastonite
perlite
pumice
vermiculite
mica and sericite (dry)
mica (wet, grinding)
mica (wet beneficiation, either no clay or
general purpose clay by-product)
barite (dry)
fluorspar (HMS)
borax
potash
trona
sodium sulfate
sulfur (anhydrite)
mineral pigments
bentonite
fire clay
fuller's earth (montmorillonite and attapulgite)
kaolin (general purpose grade)
ball clay
feldspar (non-flotation)
kyanite
magnesite
shale and common clay
aplite
talc group (dry process)
talc group (washing process)
tripoli
diatomite
jade
novaculite
The same limitations are recommended as the best available
technology economically achievable.
INDUSTRIAL SAND (HF FLOTATION)
The best available technology economically achievable is no
discharge of process generated waste water pollutants. This
technology (alternative B) involves thickening, ponding to settle
suspended solids, pH adjustment and total recycle of process
water after segregation and total impoundment of the HF-
containing segment of the process waste stream. This facility is
located in an arid region and should be able to totally impound
the HF-containing portion of its waste stream and recycle the
remainder.
U09
-------
MICA (WET BENEFICIATICN PROCESS, CERAMIC GRADE
CLAY BY-PRODUCT)
The best available technology economically achievable is the same
as the best practicable control technology currently available.
BARITE-WET (LOG WASHING, JIGGING AND FLOTATION)
The best available technology economically achievable is the same
as the best practicable control technology currently available.
FLUORSPAR (FLOTATION)
The best available technology economically achievable is the same
as the best practicable control technology currently available.
SALINES FROM BRINE LAKES
The best available technology economically achievable is the same
as the best practicable control technology currently available.
ROCK SALT
The best available technology economically achievable is:
Effluent Limitation
kg/kkg of product
(lbs/1000 Ib)
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.002 O.OOU
(Process and Mine Water)
Salt storage
Pile Runoff No discharge
The above limitations are based on the performance of at least
one facility. This technology involves the use of drum filters,
clarifiers or settling ponds to reduce suspended solids. Salt
storage pile contaminated runoff can be eliminated by building
storage silos and cones or by covering less freguently used piles
with plastic or other fabric.
PHOSPHATE ROCK
The best available technology economically achievable is the same
as the best practicable control technology currently available.
SULFUR (FRASCH PROCESS, SALT DOME OPERATIONS)
The best available technology economically achievable is:
U10
-------
Effluent
Characteristic
TSS
sulfide
Effluent Limitation
mg/1
Monthly Average Daily Maximum
30
1
60
2
The above
of the 9
subcategory
Therefore,
per unit
bleed water
the above
settling to
sulfides.
utilize its
applied on
limitations are based on the current performance of 5
facilities. The quantity of water used in this
is independent of the quantity of product.
effluent limitations based on quantity of pollutant
of production are not practical. Mine dewatering both
and seal water for this sufccategory is included in
limitations. The practiced technology is improved
reduce suspended solids and aeration to eliminate
If oxidation ditches are used by adding water to
dissolved oxygen content, the TSS limits are to be
a net basis.
SULFUR (FRASCH PROCESS - OFF SHORE SALT DOME OPERATIONS)
No limitations are proposed at this time pending further
investigation.
LITHIUM MINERALS (SPODUMENE)
The best available technology economically achievable is the same
as the best practicable control technology currently available.
KAOLIN (WET PROCESSING)
The best available technology economically achievable is the
same as the best practicable control technology currently
available.
FELDSPAR (FLOTATION)
The best available technology economically achievable is:
Effluent Limitation
Effluent
Characteristic
TSS
Fluoride
kg/kkg (1b/1000 Ib) ore processed
Monthly Average Daily Maximum
0.6
0.13
1.2
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
411
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represent the best available technology economically achievable.
This technology (alternative C) involves the recycle of 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. 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 eguipment or ponds.
TALC MINERALS GROUP (HEAVY MEDIA AND FLOTATION)
The best available technology economically achievable is:
Effluent Limitation
Effluent kg/kkg (lb/1000 Ib) of product
Characteristic Monthly Average Daily Maximum
TSS 0.3 0.6
The above limitations were based on performance of one facility
(2032) plus one facility achieving no discharge of process water
(2031). The best available technology economically achievable
for the processing of talc minerals by the ore mining, heavy
media and/or flotation process is the same as the 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. Two of the
four facilities in this subcategory are presently achieving this
level of effluent reduction using the recommended treatment
technologies.
GARNET
The best available technology economically achievable is the same
as the best practicable control technology currently available.
GRAPHITE
The best available technology economically achievable is the same
as the best practicable control technology currently available.
-------
SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
AND PRETREATMENT STANDARDS
This level of technology is to te 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 the 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 consider how the
level of effluent may be reduced by changing the production
process itself. Alternative processes, operating methods of
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 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 made of whether the introduction
of such pollutants into the treatment facility should be
completely prohibited.
-------
Untreated overflow may be discharged from process waste water or
mine dewatering impoundments without limitation if the
impoundments are designed, constructed and operated to treat all
process generated waste water or mine drainage and surface runoff
into the impoundments resulting from a 10-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 the
limitation specified as the new source performance standard. 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
dewatering waste water.
The mine dewatering limitations are the same as for the best
practicable control technology currently available. The pH
limitation for all process generated and mine dewatering waste
waters is to be between 6.0 and 9.0.
The following industry subcategories were required to achieve no
discharge of process generated waste water pollutants to
navigable waters based on the best practicable control technology
currently available:
dimension stone
crushed stone (dry)
crushed stone (wet)
crushed stone (flotation)
construction sand and gravel (dry)
construction sand and gravel (wet)
construction sand and gravel (land processing)
industrial sand (dry)
industrial sand (wet)
industrial sand (acid and alkaline flotation)
gypsum
bituminous limestone
oil impregnated diatomite
gilsonite
asbestos
wollastonite
perlite
pumice
vermiculite
mica and sericite (dry)
mica (wet, grinding)
mica (wet beneficiation, either no clay or
general purpose clay by-product)
barite (dry)
fluorspar (HMS)
borax
potash
-------
trona
sodium sulfate
sulfur (anhydrite)
mineral pigments
bentonite
fire clay
fuller's earth (montmorillonite and attapulgite)
kaolin (dry process)
ball clay
feldspar (non-flotation)
kyanite
maqnesite
shale and common clay
aplite
talc group (dry process)
talc group (washing process)
tripoli
dia tomi te
•jade
novaculite
The same limitations guidelines including those for mine
dewatering are recommended as the new source performance
standards.
The following sutcategory was reguired to achieve no discharge of
process generated waste water pollutants to navigable waters
based on best available technology economically achievable:
industrial sand (HF flotation process)
The same limitations are recommended as the new source
performance standards.
MICA (WET BENEFICIATION. CERAMIC
GRADE CLAY EY-PRODUCT)
The same as the best available technology economically
achievable.
BARITE (WET AND FLOTATION)
The same as the best practicable control technology currently
available.
SALINES FRCM EPINE LAKES
The same as the best practicable control technology currently
available.
415
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FLUORSPAR (FLOTATION)
The same as the best available technology economically
achievable.
PHOSPHATE POCK
The same as the best available technology economically
achievable.
ROCK SALT
The same as the best available technology economically
achievable.
SULFUR (FRASCH PROCESS SALT DOME)
The same as the best available technology economically
achievable.
SULFUR (FRASCH PROCESS-OFF SHORE SALT DOME OPERATIONS)
No limitations are proposed at this time pending furether
investigation.
LITHIUM MINERALS
The same as the best practicable control technology currently
available.
KAOLIN (WET PROCESS)
The same as the best practicable control technology currently
available.
FELDSPAR (FLOTATION)
The same as the best available technology economically
achievable.
TALC GROUP (HEAVY MEDIA AND FLOATION PROCESS)
The same as the best available technology economically achievable
GARNET
The same as the best practicable control technology currently
available.
416
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GRAPHITE
The same as the best practicable control technology currently
available.
PRETREATMENT STANDARDS
Recommended pretreatment guidelines for discharge of process
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:
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 to a substantial degree. The
term "incompatible pollutant" means any pollutant which is not a
compatible pollutant as defined above. A major contributing
industry is an industrial user of the publicly owned treatment
works that: 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 guality of effluent from that treatment works.
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;
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
417
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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.
The following are recommended for Pretreatment Guidelines for a
major contributing industry:
a. No pretreatment required for removal of compatible pollutants
biochemical oxygen demand, suspended solids (unless
hazardous), pH, and fecal coliform bacteria;
b. Pollutants such as chemical oxygen demand, total organic
carton, 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 the best practicable control
technology currently available recommendations for existing
sources and the new source performance standards for new
sources;
c. Limitation on dissolved solids is not recommended except in
cases of water quality violations.
d. Incompatible pollutants shall meet the limitations
representing the best practicable control technology
currently available for existing sources and the new source
performance standards for new sources.
418
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SECTION XII
AC KNOWLEDGEMENTS
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 Office, directed the day-to-day work on
the program.
Mr. Michael W. Kosakowski was the EPA Project Officer. Mr, Allen
Cywin, Director, Effluent Guidelines Division, Mr. Ernst P.
Hall, Jr., Assistant Director, Effluent Guidelines Division, and
Mr. Harold B. Coughlin, Branch Chief, Effluent Guidelines
Division, offered many helpful suggestions during the program.
Mr. Ralph Lorenzetti assisted in many facility inspections.
Acknowledgement and appreciation is also given to Linda Rose and
Darlene Miller of the word processing/editorial assistant staff
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
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
New York state Department of Environmental Conservation
419
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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 qave 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
Mr. J. Boyer, Chemical Engineer
420
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SECTION XIII
REFERENCES
1. Agnello, L., "Kaolin", Industrial and Engineering Chemistry,
Vol. 52, No. 5, May 1960, pp. 370-376.
2. "American Ceramic Society Bulletin," Vol. 53, No. 1, January
1974, Columbus, Ohio.
3. Arndt, P.H., "The Shell Dredging Industry of the Gulf Coast
Region," U.S. Department of the Interior, 1971.
4. Bates, R.L., Geology of the Industrial Rocks a,n_d Minerals,
Dover Publications, Inc., New York, 1969.
5. Beeghly, J.H., "Water Quality and the Sand and Gravel
Industry," 37th Annual Meeting Ohio Sand and Gravel
Association, 1971.
6. Black and Veatch, Consulting Engineers, "Process Design
Manual for Phosphorus Removal," U.S. EPA Program 17010 GNP
Contract 14-12-936, October, 1971.
7. Boruff, C.S., "Removal of Fluorides from Drinking Waters,"
Industrial and Engineering Chemistry, Vol. 26, No. 1, January
1934, pp. 69-71.
8. Brooks, R.G., "Dewatering of Solids," 57th Annual Convention
National crushed Stone Association, 1974.
9. Brown, W.E., U.S. Patent 2,761,835, September 1956.
10. Brown, W.E., and Gracobine, C.R., U.S. Patent 2,761,841,
September 1956.
11. "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.
12. "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.
13. Davison, E.K., "Present Status of Water Pollution Control
Laws and Regulations," 57th Annual Convention National Sand
and Gravel Association, 1973.
421
-------
14. Day, R.W., "The Hydrocyclone in Process and Pollution
Control," Chemical Engineering Progress, Vol. 69, No. 9,
1973, pp. 67-72.
15. "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.
16. "Engineering and Mining Journal," McGraw-Hill, October 1974.
17. Groom, F., "Vacuum Filtration - An Alternative to the Use of
Large Settling Ponds in Sand and Gravel Production," National
Sand and Gravel Association Circular No. 117.
18. Haden, W., Jr. and Schwint, I., "Attapulgite, Its Properties
and Applications," Industrial and Engineering Chemistry,
Vol. 59, No. 9, September 1967, pp. 57-69.
19. Huffstuter, K.K. and Slack, A.V., Phosphoric Acid, Vol. 1,
Part 2, Marcel Dekker, Inc., N.Y., 1968.
20. "Indiana Limestone Handbook," Indiana Limestone Institute of
America, Inc., January 1973, Bedford, Indiana.
21. Krenkel, P.A., "Principles of Sedimentation and Coagulation
As Applied to the Clarification of Sand and Gravel Process
Water," National Sand and Gravel Association Circular
No. 118.
22. Levine, S., "Liguid/Solids Separation Via Wet
Classification," Rock Products, September 1972, pp. 84-95.
23. Little, A.D., "Economic Impact Analysis of New Source Air
Quality Standards on the Crushed Stone Industry," EPA Draft
Report, 1974.
24. Llewellyn, C.M., "The Use of Flocculants in the James River
Estuary," Lone Star Industries.
25. Llewellyn, C.M., "Maintenance of Closed Circuit Water
Systems," National Crushed Stone Association Meeting,
Charlotte, N.C., 1973.
26. Locke, S.R., Ozal, M.A., Gray, J., Jackson, R.E. and
Preis, A., "Study to Determine the Feasibility of an
Experiment to Transfer Technology to the Crushed Stone
Industry," Martin Marietta Laboratories, NSF Contract C826,
1974.
27. Maier, F.J., "Defluoridation of Municipal Water Supplies,"
Journal AWWA, August 1953, pp. 879-888.
422
-------
28. May, E.B., "Environmental Effects of Hydraulic Dredging in
Estuaries," Alabama Marine Resources Bulletin No. 9, April
1973, pp. 1-85.
29. McNeal, W., and Nielsen, G., "International Directory of
Mining and Mineral Processing Operations," J2/MJ, McGraw-Hill,
1973-1974.
30. "Minerals Yearbook, Metals, Minerals, and Fuels, Vol. 1,"
U.S. Department of the Interior, U.S. Government Printing
Office, Washington, D.C., 1971, 1972.
31. "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 1971.
32. "Modern Mineral Processing Flowsheets," Denver Equipment
Company, 2nd Ed., Denver, Colorado.
33. Monroe, R.G., "Wastewater Treatment Studies in Aggregate and
Concrete Production," EPA Technology Series EPA-R2-73-003,
1973.
34. Newport, B.D. and Moyer, J.E., "State-of-the-Art: Sand and
Gravel Industry," EPA Technology Series EPA-660/2-74-066,
1974.
35. Oleszkiewicz, J.A. and Krenkel, P.A., "Effects of Sand and
Gravel Dredging in the Ohio River," Vanderbilt University
Technical Report No. 29, 1972.
36. Patton, T.C., "Silica, Microcrystalline," Pigment Handbook
Vol. J, J. Wiley and Sons, Inc., 1973, pp. 157-159.
37. Popper, H., Modern Engineering Cost Technigues, McGraw-Hill,
New York, 1970.
38. "Phosphorus Derived Chemicals," U.S. EPA, EPA-440/1-74-006-a,
Washington, D.C., January, 1974.
39. Price, W.L., "Dravo Dredge No. 16," National Sand and Gravel
Association Circular No. 82, 1960.
40. "Product Directory of the Refractories Industry in the U.S.,"
The Refractories Institute, Pittsburgh, Pa. 1972.
41. "Radiochemical Pollution from Phosphate Rock Mining and
Milling," National Field Investigations Center, Denver, EPA,
Denver, Colorado, December, 1973.
423
-------
42. Resource Consultants, Inc., Engineering Report, "Wastewater
Treatment for Dixie Sand and Gravel Co.," Chattanooga, Tenn.,
1972.
43. Robertson, J.L., "Washer/Classifier System Solves Clay
Problem at Sand and Gravel Facility," Rock Products, March
1973, pp. 50-53.
44. Slabaugh, W.H. and Culbertsen, J.L., J. Phys. Chem.,55, 744,
1951.
45. Smith, C.A., "Pollution Control Through Waste Fines
Recovery," National Sand and Gravel Association Circular
No. 110.
46. State Directories of the Mineral Mining Industry from 36 of
50 States.
47. Trauffer, W.E., "New Vermont Talc Facility Makes High-Grade
Flotation Product for Special Uses," Pit and Quarry,December
1964, pp. 72-74, 101.
48. Walker, S., "Production of Sand and Gravel," J. Amer.
Concrete Inst.. Vol. 26, No. 2, 1954, pp. 165-178.
49. "Water Quality Criteria 1972," National Academy of Sciences
and National Academy of Engineering for the Environmental
Protection Agency, Washington, D.C. 1972 (U.S. Government
Printing Office, Stock No. 5501-00520).
50. Williams, F.J., Nezmayko, M. and Weintsitt, D.J., J. Phys.
Chem., 57, 8, 1953.
424
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SECTION XIV
GLOSSARY
Aquifer - an underground stratum that yields water.
Baghouse - chamber in which exit gases are filtered through
membranes (bags) 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.
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.
Collector - a heteropolar compound chosen for its ability to
adsorb selectively in froth flotation and render the
adsorbing surface relatively hydrophobic.
425
-------
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. Fock 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 guarry blasting.
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.
U26
-------
Drill, rotary - various types of drill machines that rotate a
rigid, tubular string of rods to which is attached a bit for
cutting rock tc 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 resulting in 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, 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, wh( reas 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.
HMS - Heavy Media Separation
Hydraulic Mining - mining by washing sand and dirt away with
water which leaves the desired mineral.
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.
427
-------
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.
Jigging - process used to separate coarse materials in the ore by
means of differences in specific gravity in a water medium.
JTU - Jackson Turbidity Unit
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.
mgd - million gallons per day
Mill, ball - a rotating horizontal cylinder in which non-metallic
materials are ground using various types of grinding media
such as guartz 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.
Mill, hammer - 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.
428
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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.
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.
429
-------
Shuttle-car - a vehicle which transports raw materials from
loading machines in trackless areas of a mine to the main
transportation system.
SIC - Standard Industrial Classification (code).
Sink-float - processes that separate particles of different sizes
or composition on the basis cf specific gravity.
Skip - a guided steel hoppit used in vertical or inclined shafts
for hoisting mineral.
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.
Stacker - a conveyor adapted to piling or stacking bulk materials
or objects.
Stope - an excavation from which ore has been excavated in a
series of steps.
Stripping ratio - the ratio of the amount of spoil that must be
removed to the 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.
TDS - total dissolved solids.
Thickener - an apparatus for reducing the proportion of water in
a pulp.
TSS - total suspended solids.
430
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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.
431
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TABLE
CO
ro
Multiply (English Units)
ENGLISH UNIT ABBREVIATION
METRIC UNITS
CONVERSION TABLE
by To obtain (Metric units)
CONVERSION ABBREVIATION METRIC UNIT
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
oc
ac ft
BTU
BTU/lb
cfm
cfs
cu ft
cu ft
cu in
F°
ft
gal
gpm
hp
in
in Hg
Ib
mgd
mi
ps'g
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)*
0.3048
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 cat
kg cal/kg
cu m/roin
cu m/min
cu m
1
cu cm
oc
m
1
I/sec
lew
cm
atm
kg
cu m/doy
km
atm
sq m
sq cm
kkg
m
hectares
cubic meters
kilogram - calories
kilogram calories/kilogram
cubic meters/ minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
killowotrs
centimeters
atmospheres
kilograms
cubfc meters/day
kilometer
atmospheres (absolute)
square meters
square centimeters
metric tons (1000 kilograms)
meters
'Actual conversion, not o multiplier
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