United States
Environmental Protection
Agency
Office of Water
WH-552
Washington, DC 20460
EPA 440/1 -76/059b
July, 1979
v>EPA
Final
Development Document for Effluent
Limitations Guidelines and Standards
for the
Mineral Mining and Processing Industry
Point Source Category
-------
DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
for the
MINERAL MINING AND PROCESSING
POINT SOURCE CATEGORY
Douglas M. Costle
Administrator
Thomas C. Jorling
Assistant Administrator for
Water and Hazardous Materials
Swep T. Davis
Deputy Assistant Administrator for
Water Planning and Standards
Robert B. Schaffer
Director, Effluent Guidelines Division
Ronald G. Kirby
Project Officer
July 1979
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
-------
ABSTRACT
This document presents the findings of an extensive study of
the mineral mining and processing industry for the purpose
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, 1314, and 1316, 86 Stat. 816 et.
seq.) (the "Act") .
Effluent limitations 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 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
effluent limitations guidelines and standards of performance
are contained in this report.
-------
-------
CONTENTS
Section Page
Abstract i
I Summary 1
II Recommendations 3
III Introduction 9
IV Industry Categorization 85
V Water Use and Waste Characterization 89
VI Selection of Pollutant Parameters 229
VII Control and Treatment Technology 239
VIII Cost, Energy and Non-Water Quality Aspects 311
IX Effluent Reduction Attainable Through the 409
Application of the Best Practicable
Control Technology Currently Available
X Effluent Reduction Attainable Through the 437
Application of the Best Available
Technology Economically Achievable
XI New Source Performance Standards and 443
Pretreatment Standards
XII Acknowledgements 449
XIII References 451
XIV Glossary 455
111
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-------
FIGURES
Figure Page
1 Dimension Stone Distribution 16
2 Crushed Stone Distribution 20
3 Sand and Gravel Distribution 25
4 Industrial Sand Deposits 30
5 Gypsum and Asbestos Operations 36
6 Lightweight Aggregates, Mica and Sericite 36
Operations
7 Barite Processing Plants 47
8 Fluorspar Processing Plants 50
9 Potash Deposits 52
10 Borate Operations 52
11 Lithium, Calcium and Magnesium 53
12 Rock Salt Mines and Wells 53
13 Phosphate Mining and Processing Locations 60
14 Sulfur Deposts 60
15 Supply-Demand Relationships for Clays 67
16 Dimension Stone Mining and Processing 94
17 Crushed Stone Mining and Processing 97
18 Sand and Gravel Mining and Processing 103
19 Industrial Sand Mining and Processing 111
20 Gypsum Mining and Processing 118
21 Bituminous Limestone Mining and Processing, 121
Oil Impregnated Diatomite Mining and Processing,
and Gilsonite Mining and Processing
22 Asbestos Mining and Processing 123
v
-------
23 Wollastonite Mining and Processing 125
24 Perlite Mining and Processing, Pumice Mining and 127
Processing, and Vermiculite Mining and Processing
25 Mica Mining and Processing 131
26 Barite Mining and Processing 136
27 Fluorspar Mining and Processing 141
28 Minerals Recovery from Searles Lake, 147
Minerals Recovery at Great Salt Lake, and
Lithium Salt Recovery Natural Brine,
Silver Peak Operations
29 Borate Mining and Processing 151
30 Potassium Chloride Mining and Processing From 154
Sylvinite Ore, Langbeinite Mining and Processing,
and Potash Recovery by Solution Mining of Sylvinite
31 Trona Ore Processing by the Monohydrate 158
Process and Trona Ore Processing by the
Sesquicarbonate Process
32 Sodium Sulfate from Brine Wells 162
33 Rock Salt Mining and Processing 164
34 Phosphate Mining and Processing 167
35 Sulfur Mining and Processing (Frasch Process) 173
36 Mineral Pigments Mining and Processing 177
37 Spodumene Mining and Processing (Flotation 179
Process)
38 Bentonite Mining and Processing 183
39 Fire Clay Mining and Processing 185
40 Fuller's Earth Mining and Processing 187
41 Kaolin Mining and Processing 190
42 Ball Mining and Processing 193
43 Feldspar Mining and Processing 195
VI
-------
44 Kyanite Mining and Processing 199
45 Magnesite Mining and Processing 212
46 Shale Mining and Processing 205
47 Aplite Mining and Processing 207
48 Talc, Steatite, Soapstone and Pyrophyllite 210
Mining and Processing
49 Talc Mining and Processing 213
50 Pyrophyllite Mining and Processing (Heavy 214
Media Separation)
51 Garnet Mining and Processing 217
52 Tripoli Mining and Processing 219
53 Diatomite Mining and Processing 221
54 Graphite Mining and Processing 224
55 Jade Mining and Processing 226
56 Novaculite Mining and Processing 228
57 Normal Distribution of Log TSS for a Phosphate 284
Slime Pond Discharge
58 Bleedwater Treating Plant 293
VII
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TABLES
Table Page
1 Recommended Limits and Standards 5
2 Data Base 12
3 Production and Employment 14
4 Dimension Stone by Use and Kind of Stone 17
5 Size Distribution of Crushed Stone Plants 19
6 Uses of Crushed Stone 23
7 Size Distribution of Sand and Gravel Plants 26
8 Uses of Sand and Gravel 28
9 Uses of Industrial Sand 31
10 Industry Categorization 86
11 Dimension Stone Water Use 95
12 Settling Pond Performance Stone, Sand and 247
Gravel Operatons
13 Fluorspar Mine Dewatering Data 279
14 Sulfur Facilities, Comparison of Discharges 290
15 Dimension Stone Treatment Costs 316
16 Crushed Stone Treatment Costs 318
17 Construction Sand and Gravel (Wet Process) 324
Treatment Costs
18 Industrial Sand (Wet Process) Treatment Costs 331
19 Industrial Sand (Acid and Alkaline Process) 334
Treatment Costs
20 Industrial Sand (HF Flotation) Treatment Costs 336
21 Gilsonite Treatment Costs 339
22 Vermiculite Treatment costs 342
IX
-------
23 Mica Treatment Costs 344
24 Barite (Wet Process) Treatment Costs 350
25 Barite (Flotation Process) Treatment Costs 353
26 Fluorspar (HMS Process) Treatment Costs 355
27 Fluorspar (Flotation Process) Treatment Costs 357
28 Borates Treatment Costs 360
29 Potash (Carlsbad Operations) Treatment Costs 362
30 Potash (Moab Operations) Treatment Costs 363
31 Trona Treatment Costs 365
32 Rock Salt Treatment Costs 369
33 Phosphate Rock (Eastern) Treatment Costs 372
34 Phosphate Rock (Western) Treatment Costs 374
35 Sulfur (Anhydrite) Treatment Costs 377
36 Sulfur (On-Shore Salt Dome) Treatment Costs 379
37 Sulfur (Off-Shore Salt Dome) Treatment Costs 381
38 Mineral Pigments Treatment Costs 383
39 Lithium Minerals Treatment Costs 385
40 Attapulgite Treatment Costs 387
41 Montmorillonite Treatment Costs 388
42 Montmorillonite Mine Water Treatment Costs 389
43 Wet Process Kaolin Treatment Costs 392
44 Ball Clay Treatment Costs 394
45 Wet Process Feldspar Treatment Costs 396
46 Kyanite Treatment Costs 399
47 Wet Process Talc Minerals Treatment Costs 403
48 Conversion Table 462
x
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SECTION I
SUMMARY
This study included the non-metallic minerals given in the
following list with the corresponding Standard Industrial
Classification (SIC) code.
Dimension Stone (1411)
Crushed Stone (1422, 1423, 1U29)
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 (Prasch) (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)
-------
A. Garnet
B. Tripoli
Diatomite (1499)
Graphite (1499)
Miscellaneous Non Metallic Minerals (1499)
A. Jade
B. Novaculi te
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SECTION II
RECOMMENDATIONS
A summary of the effluent limitations is set forth in Table
-1. •
This development document is issued in support of final
effluent limitations guidelines, based on the best
practicable technology currently available (BPT), for
existing sources in the 'following subcategories of the
mineral mining point source category:
Crushed Stone
Sand and Gravel
Industrial Sand
Phosphate Rock
This development document also incorporates the
documentation which was issued earlier in support of interim
final regulations which were published on October 16, 1975
for the following additional subcategories:
Gypsum Sodium Sulfate
Asphaltic Minerals Frasch Sulfur
Asbestos and Wollastonite Bentonite
Barite Magnesite
Fluorspar Diatomite
Salines Jade
Borax Novaculite
Potash Tripoli
Graphite
Furthermore,this development document incorporates the documentation
which was developed earlier in support of proposed regulations
issued on October 16, 1975 and June 10, 1976 for the following
subcategories:
Crushed Stone Gypsum Potash
Sand and Gravel Asphalt Sodium Sulfate
Industrial Sand Asbestos Frasch Sulfur
Phosphate Rock Barite Bentonite
Fluorspar Magnesite Novaculite
Salines Diatomite Tripoli
Borax Jade Graphite
Finally, this development document sets forth in draft form
the basis for developing at a later date limitations for the
following subcategoriess
-------
Dimension Stone Rock Salt
Lightweight Aggregate Minerals Mineral pigments
Mica and Sericite Lithium Minerals
Salines from Brine Lakes Fine clay
Trona Fuller's Earth
Talc, soapstone,pyrophyllite
and steatite Shale and other clay
Garnet
-------
TABLE 1
Recommended Limits and Standards
The following apply to process waste water except where noted.
Subca.teoory
BPCTCA
max. avg. of 30
consecutive .days
ma*, for
any one day
Dimeris-i'on stone
Mine dewa.tering
Crushed stone TSS 25 mg/1
Mine dewatering TSS 25 mg/1
Construction Sand and Gravel TSS 25 mg/1
No discharge
TSS 30 nig/1
TSS 45 mg/1
TSS 45 mg/1
TSS 45 mg/1
cn
Mine dewatering
Industrial Sand
Dry. processing,
Wet processing, &
Won HF flotation
HF flotation
TSS 25 mg/1
TSS 45 mg/1
Acid Leaching
Mine dewatering
Gypsum
Dry &
Heavy Media Separation
Wet scrubbers
Mine dewatering
Bituminous limestone,
011-impregnated diatomite, &
Gilsphite
Asbestos Wollostonite
Mine dewatering
Perlite, Pumice, Vermiculite
& Expanded 1ightwelght aggregates
Mine dewatering
Mica & Sericite
Dry processing.
Wet processing &
Wet processing and
general clay recovery
Wet. processing and
Ceramic grade clay
recovery
Mine dewatering
Barlte
Dry
Wet & Flotation
Tai1 ings pond
storm overflow
Min-e dewatering
(acid)
Mine dewatering
(non acid)
No d-i scharge
TSS 25 mg/1 TSS 45 mg/1
TSS 0.023 kg/kkg TSS 0.046 kg/kKg
F 0.003 kg/kkg F 0.006 kg/Kkg
No recommendation
TSS 25 mg/1 TSS 45 ma/1
No discharge
No discharge
TSS 30 mg/1
No discharge
No discharge
TSS 30 mg/1
No discharge
TSS 30 mg/1
No discharge
BATEA and NSPS
max. avg. of 30 .max. for
consecutive days any one day
No discharge-
TSS 30 mg/1
TSS 25 mg/1 TSS 45 mg/1
TSS 25 mg/1 TSS 45 mg/1
TSS 25 mg/1 TSS 45 mg/1
TSS 25 mg/1 TSS 45 mg/1
No discharge
TSS 25 mg/1 TSS 45 tng/1
No discharge
No recommendation
TSS 25 mg/1 TSS 45 mg/1
No discharge
No discharge.
TSS 30 tng/1
No discharge
No di scharge
TSS 30 tng/1
No discharge
TSS 30. ing/1
No discharge
TSS 1.5 kg/kkg
TSS 3.0 kg/kkg
TSS 30 mg/1
TSS 1.5 kg/kkg
TSS 3.0 kg/kkg
TSS 30 mg/1
No discharge
No discharge
TSS 30 mg/1
No discharge
No discharge
TSS 30 mg/1
TSS 35 mg/1
Total Fe 3.5 mg/1
TSS 70 mg/1
Total Fe 7.0 mg/1
TSS 35 mg/1
TSS 35 mg/1
Total Fe 3.5 mg/1
TSS 70 mg/1
ToTai Fe 7.0 mg/1
TSS 35 mg/1
-------
Fluorspar
Heavy Media Separation
8 Drying and Palletizing
Flotation TSS
F 0
Mine Drainage
Salines from Brine Lakes**
Borax
Potash
Tnona (process waste water &
mine dewatering)
Sodium Sul fate"
Rock Salt (process waste water
No discharge
0.6 kg/kkg TSS 1.2 kg/kkg
2 kg/kkg F 0.4 kg/kkg
TSS 30 mg/1
No discharge
No discharge
No discharge
No .discharge
No discharge
mine dewatering)
Salt pi1e runoff
Phosphate Rock
and mine dewatering
Sulfur (Frasch)
Anhydri te
Salt domes(land 'and
marsh operations
we)1 bleed water)
Land avallable
Limited Land
available
.Wei 1 seal water
TSS 0.02 kg/Kkg TSS 0.04 kg/kkg
TSS 30 mg/1
TSS 60 mg/1
TSS
No discharge
50 mg/1* TSS 100 mg/1*
mg/1 S 2 mg/1
mg/1 S 10 -mg/1
No
.Mineral Pigments
Mine dewatering
Li thium***
Tailings dam seepage &
storm overflow
Mine dewatering
Bentonite
Mine dewatering
Fire clay
Nbn-Acid mine dewatering
Acid Mine dewatering TSS 35 mg/1
Total Fe 3.5
Attapulgite No
Mine dewatering
Montmori1loni te
Mine dewatering
Kaolin
Dry processing
Wet processing
No
No
No
No
discharge
TSS 30 mg/1
discharge
TSS. 50 mg/1
TSS 35 ma/1
discharge
TSS 35 m9/l
discharge
TSS 35 mg/1
TSS 70 mg/1
mg/1 Total Fe 7 mg/1
discharge
TSS 35 mg/1
discharge
TSS 35 mg/1
No
Turbidi.ty 50
TSS 45 mg/1
Zn 0.25 mg/1
Turbidity 50
(ore slurry pumped) TSS 45 mg/1
Mine dewatering
(ore dry transported)
Wine aewatefing
discharge
JTU Turbidity 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/kkq
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
Np discharge
TSS 30 mg/1
TSS 30 mg/1*
S 1 mg/1
S 2 mg/1
TSS 60 mg/1
TSS 60 mg/U
S 2 mg/1
S 4 mg/1
TSS 30 mg/1.* TSS 6a mg/1*
S 1 mg/1 . 52 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/1
No discharge
TSS 35 mg/1
No discharge
TSS 35 mg/1
No discharge
.Turbidity 50 JTU
TSS 45 mg/1
Zn 0.25 mg/1
Turbidity 50 JTU
TSS 45 mg/1
Turbidity 100 dTU
TSS 90 mg/1
Zn 0.50 mg/1
Turbidity 100 JTU
TSS 90 mg/1
TSS 35 mg/.l
-------
BalV Clay
Dry processing
Wet processing
Mine dewaterlng,
Feldspar
Non-Flotation plants
Flotation plants***
Mine dewatering
Kyanite
Mine dewaterlng
Magesite
Shale and Common Clay
Mine dewatening
Apllte
Mine dewatering
Talc, Steatite, Soapstone
Dry pPocessing &
hashing plants
Flotation and HMS
plants
Mine dewatePtng
Gapnet
Tripoli
Mine dewatering
Diatomite
Mine dewatening
Graphite (process and
Mine dewaterlng)
Jade
Novaculite
No discharge
No discharge
TSS 35 mg/1
No discharge
TSS 0.6 kg/kkg TSS 1 .2 kg/kkg
F 0.175 kg/kkg F 0.35 kg/Xkg
TSS 30 mg/1
No discharge
TSS 35 mg/1
No discharge
No discharge
TSS 35 mg/1
No discharge
TSS 35 mg/1
and Pyrophyl1ite
No discharge
No discharge
No discharge
TS.S 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 nig/1
No discharge
TSS 0.5 kg/kkg
TSS 1.0 kg/kkg
TSS 30 mg/1
TSS 60 mg/1
TSS 0.3 kg/kkg
TSS 0.6 kg/Xkg
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
TSS 30 tng/1
TSS 30 mg/1 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/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 if oxidation ditches are used and intake 1s from the same navigable
water as the discharge.
** standards are to be applied as net if discharge is to the same navigable water as brine Intake
*** kg of pollutant/kkg of ore processed
BPCTCA - best practicaole control technology currently available
BATE* - best available technology economically achievable
NSPS - new source performance standard
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SECTION III
INTRODUCTION
The United States Environmental Protectiori 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 30(1 (b) also requires
the achievement by not later -than July 1, 1983, of effluent
limitations for point sources, other than publicly owned
treatment works, which are based on the application of the
best available technology economically achievable which will
result in reasonable further progress toward the national
goal of eliminating the discharge of all pollutants, as
determined in accordance with regulations issued by the
Administrator pursuant to Section 304 (b) 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 alterna-
tives, 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. 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 16r 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^ 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.
10
-------
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 high polish. Many other
rocks such as serpentines, onyx, travertines, and some
granites are frequently called marble by the dimension stone
industry. Hard cemanted 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
Georgia
Vermont
Massachusetts
South Dakota
11
-------
No.
Subcategory Plants
Dimension Stone 194
Crushed Stone 4800
Dry
Wet
Flotation 8
Shell Dredging 50
Construction Sand
Gravel
Dry 750
Wet 4,250
Dredging (on-land) 50
Dredging (on-board) 100
Industrial Sand
Dry 20
Wet 130
Flotation 17
Add Leaching 3.
• Flotation (HF) 1
Gypsum
Dry 73
Wet Scrubbing 5
HMS 2
Asphaltlc Minerals
Bituminous Limestone 2
Oil Impreg.Dlatomite 1
Gilsonlte 1
Asbestos
Dry 4
Wet 1
Wollastonlte 1
Lightweight Aggregates
Perlite 13
Pumice 7
Vermiculite 2
Mica & Sericite
Dry 7
Wet 3
Wet Beneficiatibn 7
Barite
Dry 9
Wet 14
Flotation 4
Fluorspar
HMS 6
Flotation 6
Drying and 2
Pelletizing
TABLE 2
DATA BASE
Visited
20
5
26
2
4
0
46
8
3
0
3
4
3
1
5
1
1
0
1
1
2
1
1
4
2
2
5
2
5
4
7
3
4
4
1
No Plants
Data
Available
20
52
130
3
4
50
100
15
25
5
10
10
3
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
0
1
2
1
*
*
*
1
1
*
*
*
*
*
*
*
*
*
1
*
2
*
-------
Salines from . 3 3 3 *
Brine Lakes
Borax 1 1 1 *
Potash 5 4 5 *
Trona Ore 4 2 . 4 *
Phosphate Rock
Eaatevtt 22 21 20. 3
HMt«rn 66 6 a
Jtoefc «alt 21 11 15 3
Sulfur
Anhydrite 2 1 2 *
On-Shore 97 95
Off-Shore 2 1 1 1
Mineral 11 3 3 *
Figments
Lithium 22 22
Minerals
Sodium 6 2 2 *
Sulfate
Bentonite 37 2 2 *
Fire Clay 81 9 9 *
Fuller's Earth
Attapulgite 10 4 52
Montmor. 43 33
Kaolin
Dry 4 4 *
Wet 37 total 6 70
Ball Clay 12 4 4 0
Feldspar
Wet 5 5 55
Dry 2 2 2 *
Kyanite 32 2 *
Magnesite 1 1 1 *
Shale and Common 129 10 20 *
Clay
Aplite 2 2 2 *
Talc Minerals
Dry 27 12 20 *
Washing 2 1 2 *
QMS, Flotation 44 4 4
Natural Abrasives
Garnet 3 2 20
Tripoli 42 4 *
Diatomite 93 3 *
Graphite 1 1 1 0
Misc. Minerals
Jade est. 10 1 1 *
Novaculite 11 1 *
Total 11,019 312 735 77
*There is no discharge of process waste water in the subcategories
under normal operating conditions.
13
-------
TABLE 3
Production and Employment
SIC Code Product
1411
1411
1411
1422
1423
1429
1499
1442
1446
1492
1499
1499
1499
1499
1499
1499
1499
1499
1499
1472
1473
1474
1474
1474
1474
1475
1476
1477
1479
1479
1452
1453
1454
1455
1455
1459
1459
1459
1459
1459
1496
1496
1496
1499
1499
1499
1499
1499
Dimension stone-limestone
Dimension stone-granite
Dimension stone-other*
Crushed & broken stone-
limestone
Crushed & broken stone
granite
Crushed & broken stone NEC
Crushed & broken stone shell
Construction sand & gravel
Industrial sand
Gypsum
Bituminous limestone
Oil-impregnated diatomite
Gilsonite
Asbestos
Wollastonite
Perllte
Pumice
Vermiculite
Mica
Barlte
Fluorspar
Borates
Potash (K2) equiv.
Soda Ash Ttrona only)
Sodium sulfate
Phosphates
Salt (mined only)
Sulfur (Frasch)
Mineral pigments
Lithium minerals
Bentoni te
F1re clay
Fuller's earth
Kaolin
Ball clay
Feldspar
Kyanite
Magnesite
Aplite
Crude common clay
Talc
Soapstone
Pyrophyllite
Abrasives
Garnet
Tripoli
Dlatomite
Graphite
Jade
Novaculite
HiBbM 1000 tons
542 598
357 394
559 616
542,400 598,000
95,900 106,000
113,000 124,600
19,000 20,900
650,000 717,000
27,120 29,999
11,200 12,330
1 ,770 1 ,950
109 120
45 50
120 132
63 70
589 649
3,460 3,810
306 337
145 160
822 906
22S 251
1,0*0 1 JtP
Z.,410 2'if$
2,920 3*111
636 Ml
37,000 40,i3&
12,920 14,209
7,300 8,Q4fi
63 n
Withheld
2;1§0 2,767
3,250 3,581
896 988
4,810 5,318
-&]£ ,575
mi 132
Est. 10$ Est* 120
Withheld
190 210
41,840 46,127
1,004
17 19
80 SS
5Z2 576
Withheld
.107 .118
Withheld
Employment
2,000 combined
SIC 1411
29,400
4,500
7,400
Unknown
30,300
4,400
2,900
Unknown
Unknown
Unknown
400
70
300
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
*Sandstone, marble, et al
**Includes ball clay
14
-------
Marble - Georgia
Vermont
Minnesota (dolomite)
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 mining activities in
the U.S. Present production methods for dimension stone
range 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 siter 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.
15
-------
FIGURE 1
DIMENSION STONE DISTRIBUTION
BTOENSIONAL ORAMITF
1972- 10(10 short eons
* Producing States ftqtal - 214) Data fron: Mineral's Yearbook- 1972.
National Total - 621.2 • Vol. I, Table S, p. 1164,
DIMENSIONAL LIMESTONE
1972- 1000 shore eons
* Producing State* (Total • 54.8) Data from: Minerals Yearbook
National Total - 411.1 'excluding P.R.) 1972, Vol,I, Table 6,p. 1164
DIMENSIONAL SANDSTONE.
QUARTZ, QOARTZITE
* Producing States (Total - 22.3) Data fromi Minerals Yearbook-1072
Rational Total - 230.7- Vol.r> Table 7) p.U6S|
16
-------
TABLE 4
DIMENSION STONE BY USE AND KIND OF STONE
1972)
Kind of atone and use
GRANITE
1000 short tons
Kind of stone and use
continued
Dressed:
1000 short tons
Rough :
ArchlTOCtural
Construction
Monumental
Other rough stone
Dressed :
Cut
Sawed
House stone veneei
Construction
Monumental
Curbing
Flagging
Paving blocks
Other dressed stone.
Total
Value ($1006)
LIMESTONE AND DOLOMITE
Rough;
Architectural
Construction
Flagging
Other rough stone
Dressed:
Cut
Sawed
House stone veneer
Construction
Flagging
Other dressed stone
Total
Value ($1000)
MARBLE'
Rough: Architectural
Dressed:
Cut
Sawed
House stone veneer
Construction and Monumental
Total
Value ($1000)
SANDSTONE, QUAKTZ & QUARTZITE •
Rough:
Architectural
Construction
Flagging
Other rough stone
46
54
287
--
«.
14
6
10
33
130
—
«.
42
621
42,641
175
56
18
1
49
•30
6B
12
2
1
411
14,378
9
21
5
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
Kills tock:
Structural and sanitary
Blackboards, etc.
Billiard table tops
Total
Flagging
Other uses not listed
Total
Value ($1000)
OTHER STONE
Rough:
Architectural
Construction
Dressed:
Cut
Construction
Flagging
Structural and sanitary purposes
Total
Value ($1000)
• - ' ,
TOTAL STONE
Rough :
Architectural
Construction
Monumental
Flogging •
Other rough stone
Dressed:
Cut
Saved
House stone -veneer
Construction
Roofing (elate)
HlllBtock (elate)
Monumental
Curbing
Flagging
Other uses not listed ,
Total
Value ($1000)
21
--
—
27
17
32
231
7,684 •
12
14
1
• 4
19
36
14
80
7,404
14
43
2
4
66
1,964
286
239
287
36
,2
117
65
110
32
12
19
65
130
61
31
1,490
90,763
Minerals Yearbook, 1972, U.S. Department of the Interior,
Bureau of Minos
-------
CRUSHED STONE (SIC 1422, 1423 and 1429)
This stone category pertains to rock which has been reduced
in size after mining 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.
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 quartzose 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.
18
-------
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
19
-------
FIGURE 2
CRUSHED STONE DISTRIBUTION
CRUSHED GRANITE
1972/1.000.000 short tons
'Total -106.3
CRUSHED LIMESTONE
AND DOLOMITE
1972/1.000.000 short tons
•* Total stone - crushed S dimensional
* Other producing States (total « 8.2)
National total (excluding P.R. 4 territories) • 663.3
'Pacific Island* « .9
Data From: Mineral Yearbook - 1972. Vol. t
Table 13. p. 1170
20
-------
Most crushed and broken stone is presently mined from open
quarries, 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 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.
21
-------
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 equipment 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 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 nun 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
22
-------
TABLE 6
USES OF CRUSHED. STONE"
Kind of (tone and ua«
CALCAREOUS MARL
quantity
(1000 tcmu)
Agricultural purposes
Cement manufacture' . •
Other uses
.Total
Value ($1000)
. GRANITE
Agricultural purposes
Concrete aggregate (coarse)
Bituni-fnoue aggregate • .< .'
H'jodam aggregate
Donse graded road base stone
Surface treatment aggregate
Unspecified construction aggregate and roadstone
Riprap and jetty stone
' Railroad ballast
Kilter stone -
Fill . •:''..•
Other uses
Total
Value ($1000)
LIMESTONE AM) DOLOMITE
Agricultural purposes
Concrete aggregate (coarse) . ' • . •
Bituminous aggregate
Macadam
Dense graded road base stone
Surface treatment aggregate
Unspecified construction aggregate aad roadatone
Riprap and jetty stone
Railroad ballast
Filter stone
Manufactured fine aggregate (stone sand)
Terrazzo and exposed aggregate
Gem-it manufacture
Lime manufacture
Dead-burned dolomite
Ferrosilicon
Flux stone
Refractory stone
Chemical stone for Alkali Works
Special uses and products
Mineral fillers, extenders, and whiting
Chemicals
Fill
.Glass
' Sugar refining
Other uses
Total
Value ($1000)
MARBLE
Agricultural purposes
Macadam aggregate
Concrete- aggregate (coarse) .
iDense graded road base stone
Unspecified construction aggregate and roadstone
Riprap and jetty stone
Filter stone
Manufactured fine aggregate (stone sand)
Terrazzo and exposed aggregate
Mineral fillers, extenders, and whiting
• Other uses
Total
Value ($1000)
SANDSTONE, QUARTZ, AND QUASTZITE
Concrete aggregate (coarse)
Bituminous aggregate
Hacadam aggregate
Dense graded road base stone
Surface treatment aggregate '
Unspecified construction aggregate and roadatone
Riprap and jetty atone
Railroad balla>t
Filter stone
Manufactured fine aggregate (erone eand)
TerrazEO .and «xpoaed aggregate
133
2,517
2,650
3,598
18,579
16,088
3,966
.37,877
,5,695
10,048
4,036
6,162
97
3,718
106.266
182,930
27,140
100,173
49,977
26,993
139,257
38,704
71,647
12,935
7,250
339
4,752
124
101,304
28,858
1,670
1.030
24,728
395
4,199
876
2,984
635
. 4,243
1,794
560
18,930
671,496
1,090.707
44
83
862
203
1,047
8
2,247
25,005
2.092
1,613
351
8,744
951
3,290
2,213
1,014
52
343
23
Kind of stone «iid vat tjunntity
,']00l> tons)
SANDSTONE, QUARTZ, AHD QUART21TE
(continued) .
Cement and lime manufacture . . ' . 522
Ferroallicon - 227
Flux stone . lilOZ
Refractory stone 211
Abrasives *5
Glass 925
Other uses 3,100
Total . 26,817
Value ($1000) 57,994
SHELL
Concrete aggregate (coarse)
Dense graded road base stone 1,675
Unspecified construction aggregate a,.d roadstone . 3,281
Cement and lime manufacture 5,67^
Other uses 3,98^
Total 16,610
Value ($1000) 29,571
TRAPROCK
Agricultural purposes. . • 444
Concrete aggregate (coarse) 6,643
Bituminous aggregate i 11,469
Macadam aggregate 1,438
Dense graded road base stone 19,361
Surface treatment aggregate 5,341
Unspecified construction aggregate and roadstone ' 23,811-.
Riprap and jetty stone 3^623
Railr id ballast 2,332
Filter atone 117
Manufactured fine aggregate (stone sand) 231
Fill . 1.686 .
Other uses 3,966
Total 80,462
Valuf ($1000) 170,823
•QTHER STONE
Concrete aggregate (coarse) 1,159
Bituminous aggregate 2,202
Macadam aggregate 278
Dense graded mod base stone 3,051
Surface treatment aggregate 591
Unspecified construction aggregate and roadstone 2,911
Riprap and jetty stone 1,738
Railroad ballast . • ~r
Mineral fillers, extenders and whiting —
Fill 578
Other uses 1,789
Total 14,298
Value ($1000) 24,442
TOTAL STONE
Agricultural purposes 23,393
Concrete aggregate (coarse) 133,471
Bituminous Aggregate 82,560
Macadam aggregate 33,110
Dense graded road base stone 210,013
Surface treatment aggregate 51,943
Unspecified construction aggregate and roadotone 113,406
Riprap and jetty stone ' 24,560
Railroad ballast 18,021
Filter atone 636
Manufactured fine aggregate (stone sand) • 5,869
Terrazzo and expoecd aggregate 402
Cement manufacture 108,857
Lime manufacture 30,051
Dead-burned dolomite 1,670
Ferrosilicon . 1,257
Flux atone . 25,830
Refractory 8tone 605
Chemical atone for alkali works, 4,199'
Special uoea and products - 1,071
Mineral fillers, extenders and whiting 4,423
Fill ; 6,630
Mass 2,718
Expanded slate . 1,270
Other luica 31,394
Total ' 922,361
Value ($1000) 1,592,569
Minerals Yearbook, 1972, U.S. Department of. the Interior
Km ran of Mlnn«
23
-------
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 quality 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.
The crushed stone and sand and gravel industries, on the
basis of tonage 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 (4 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 HO 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.
24
-------
FIGURE 3
SAND AND GRAVEL DISTRIBUTION
PRODUCTION,
1972/1,000,000 short tons
National Total (excluding P.ft.) • 913.2
Oat* Fran: Minerals Yearbook - 1972, Vol. I
Tabli.3, p. 1111-1112'
Bureau of HInit
Data From: Minerals Yearbook - 1972
VolII
flureau of Mines
25
-------
TABLE 7
Size Distribution of Sand and Gravel Plants
Total
5,384
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
785,788
100.0
Minerals Yearbook, 1972, U.S. Department of the Interior,
Bureau of Mines, Vol I, page 1120
26
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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 rtotal 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 14 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-lpaders 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 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 sand 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
27
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Table 8
Uses of Sand and Gravel
Use
Quantity
1000 kkg 1000 short tons
Building
Sand
Gravel
Paving
Sand
Gravel
Fill
Sand
Gravel
Railroad Ballast
Sand
Gravel
Other
Sand
Gravel
Total
Value ($1000)
Value X$/Quantity)
170,329
139,001
119,182
254,104
44,050
39,416
948
2,022
8,685
11,682
789,419
1.35
187,794
153,254
131,402
280,159
48,567
43,458
1,045
2,229
9,575
12,880
870,363
1,069,374
1.23
Minerals Yearbook, 1972, U.S. Department of the Interior
Bureau of Mines
28
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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 guartzite, 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 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
29
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FIGURE 4
INDUSTRIAL SAND DEPOSITS
00
o
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 9821
Molding 6822
Grinding and polishing 238
Blast sand 972
Fire or furnace 638
Engine (RR) 545
Filtration 212
Oil Hydrofrac 256
Other 3187
Ground Sand 4092
Total 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
5.26
4.20
3.81
,30
,79
,86
,19
,30
,02
,79
3.38
4.77
3.81
Minerals Yearbook, 1972, U.S. Department of the Interior,
Bureau of Mines
31
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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 age occurs as
steeply dipping beds in the Appalachian Highlands.
Production, in order of importance, is centered in West
Virginia, Pennsylvania, and Virginia. The St. Peter
sandstone of Lower Ordovician age occurs as flatlying beds
in the Interior Plains and Highlands 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 Clean
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 roughly decreasing order of economic importance.
Marginal deposits of coarse quartzose gravel occur in
Kentucky. Terrace deposits of vein quartz gravel in
California have supplied excellent material for ferrosilicon
use.
32
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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
quartz 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 quartzose rock or quartz
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 Mid-
west where the foundry and steel business is centered. A
large volume is produced from pebbly phases of the Sharon
conglomerate in Ohio. The Veria sandstone of Mississippian
33
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age is crushed and pelletized 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. 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 (CaSCW»2H2O) 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 (CaSO4) 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 hammermi11s.
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.
35
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FIGURE 5
GYPSUM AND ASBESTOS OPERATIONS
a I •GYPSUM
• ASBESTOS
FIGURE 6
LIGtfTWEIGKT AGGREGATES, MICA AND SERICITE OPERATES
• MICA AND SERICITE
9 PERLITE
PUMICE
VERMICULITE
36
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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.
Most crushed gypsum is calcined to the hemi-hydrate stage by
one of six different methods - kettles, rotary calciners,
hollow-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, cpnspicuous by their hardness, brittleness
and comparatively high softening point.
(3) Asphaltic bitumens obtained from nbn-asphaltic and
asphaltic crude petroleum by distillation, blowing with
air and the cracking of residual oils.
Asphaltic pyrobitumens of which wurtzilite and elaterite
are of chief interest industrially as they depolymerize
37
-------
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, 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 1/4 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 48 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.
38
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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 204°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 4.8 km
(3 miles) in length. It is used in the manufacture of
paints, varnishes, as an extender in hard rubber compounds,
and various weatherproofing 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 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.2.2H2O 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.
39
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In North America the methods of asbestos mining are (1) open
quarries, (2) open pits with glory holes, (3) shrinkage
stoping, and (4) block caving; the tendency is toward more
underground mining. In quarrying, the present trend is to
work high benches up to H6 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
requirements. The general method in use is (1) coarse
crushing in jaw or gyratory crushers, sometimes in two
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; (4) 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, CaSiO3, 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 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.
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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 percent combined calcium, magnesium, and iron oxides for
the most basic types.
The distribution of pumice is world wide, but due to meta-
morphism 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.
42
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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, 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 4 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.
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MICA (SIC 1499)
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 quarrying methods are used
to develop deposits for the extraction of
small-particle-size mica and other co-product minerals.
44
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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 & 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.
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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 sequence 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 quarries with little or no
subsequent 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 concentrates. 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
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FIGURE 7
BARITE PROCESSING PLANTS
Da$a From: Industrial and Chemical Mineral
Chart,-:p. 184
The National Atlas of the USA
USGS - 1970
-------
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 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 1473)
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 fluoro-
carbon chemicals which are formulated into refrigerants,
plastics, solvents, aerosols, and many other industrial
products.
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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 BRINE 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
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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
-------
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 California as bedded deposits
of borax (sodium borate) and colemanite O30>| and sassolite (natural boric acid) , H3_BO3_.
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 (B2O3J 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.
51
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FIGURE 9
POTASH DEPOSITS
*-Mines
*-Mel Is
-Surface brines
From Salines chart-pg.181
The National Atlas.of The USA
USGS-1970 '. .-
FIGURE 10 •
BORATE OPERATIONS
From Salines ch.irt-pq.181
The National Atl.r, of The USA
USGS-1970
52
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FIGURE 11
LITHIUM, GALCIUM AND MAGNESIUM
• Lithium
• Calcium comnounris(Brine)
x; Magnesium comp.fUrine)
From Salines Chart-pg.181
The National Atlas of The USA
US6S-1970
FIGURE 12
ROCK SALT MINES AND WELLS
Fran Saline chdrt-pg.181
The Nation,!I. Atlas of The US/J
4JSIK-1970
53
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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.
Borax (Na2BfK)7» 10H20) , 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
(Na2_B4p7^5H2O) and anhydrous forms are sold. The various
grades are available in crystalline, granular, or powder
forms. Boric acid (H3BO.3) 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 1474)
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 K2_0
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 K2:O) 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
54
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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. Room-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.
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 Iangbeinite 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
liquor 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 centrifuging.
55
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About 84 percent of the domestic potash is produced in a 142
square km (55-square mile) area 24 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.
TRONA (SIC 1474)
Trona (Na2CO3_NaHCO^«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
world1s 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 trona-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).
56
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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 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
57
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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 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_(PO4)3_ -
58
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(F, Cl, OH). The (F, Cl, OH) radical may be all fluorine,
chlorine, or hydroxyl ions or any combination thereof. The
(PO4J radical can be partly replaced by small quantities of
VO4, AsO4., SiO<^, SO^, 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 conso-
lidated 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 pro-
ducing 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 (49 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.
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 14,
plus 150 mesh) that has been treated in flotation cells,
spirals, cones or tables. Losses in washing and flotation
operations, which range from 40 percent of the phosphorus in
the Florida operations to more than 50 percent in some
Tennessee areas, occur in the form of slimes containing 4 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
59
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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 tmto-jtrlal and Chemical Minerals chart-
P'|.1R4
The National Atlas of The USA
USGS-WO
60
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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 very 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.
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.
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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 liquid sulfur is
pumped directly into heated and insulated ships or barges
that can transport the sulfur in liquid 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.
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.
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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, sandse 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. 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.
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LITHIUM MINERALS (SIC 1479)
Spodumene, petalite, lepidolite, and amblygonite 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 whidtj 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 com-
pound .
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 con-
centrated 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.
CLAYS
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Clays and other ceramic and refractory materials differ
primarily because of varying 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 Al^q3SiO_3.xH2p. Important
impurities are iron, calcium, magnesium, potassium, and
sodium which can either be located interstitially in the
hydrous aluminum silicate matrix or can replace elements in
the clay minerals. As it may be imagined there is a
infinite mixture of clay minerals and impurities, and a
solution for nomenclature would seem insurmountable. The
problem is solved somewhat haphazardly by classifying a clay
according to its principal clay mineral (e.g. kaolin-
kaolinite), by its commercial use (e.g. fire clay and
fuller's earth) or by its properties (e.g. plastic clay).
Much clay, however, is called just common clay. Some of the
principal clay minerals are kaolinite, montmorillonite,
attapulgite, and illite.
Kaolinite consists of alternating layers of silica
tetrahedral sheets and alumina octahedral sheets.
Imperfections and differences in orientation within this
stacking will lead to differences in the kaolinite mineral.
Each unit within the montmorillonite stack is composed of
two silica tetrahedral sheets sandwiching a alumina
octaheldral sheet. Because of the unbalanced forces between
sucessive units, polar molecules such as water can enter
and distribute the charges. This accounts for the swelling
properties of montmorillonite bearing clays. The presence
of sodium, calcium, magnesium and iron between units will
also affect the degree of swelling. The unit structure of
attapulgite is comprised of two silica chains liked by
octahedral groups of hydroxyls and oxygens together with
aluminum and magnesium. The emperical formula is (Mg,Al)I>
S±8O22(QK}il9ilH2p. 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.
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Most clays are mined from open pits, using modern surface
mining equipment such as draglines, power shovels, scraper
loaders, and shale planers. A few clay pits are operated
using crude hand mining methods. A small number of clay
mines (principally underclays in coal mining areas) are
underground operations employing mechanized room and pillar
methods. Truck haulage from the pits to processing
facilities is most common, but other methods involve use of
rail transport, conveyor belts, and pipelines in the case of
kaolin. Recovery is near 100 percent of the minable beds in
open pit mines, and perhaps 75 percent in the underground
operations. The waste to clay ratio is highest for kaolin
(about 7:1) and lowest for miscellaneous clay (about
0.25:1).
Processing of clays ranges from very simple and inexpensive
crushing and screening for some common clays to very
elaborate and expensive methods necessary to produce paper
coating clays and high quality filler clays for use in
rubber, paint, and other products. Waste material from
processing consists mostly of quartz, mica, feldspar, and
iron minerals.
Clays are classified into six groups by the Bureau of Mines,
kaolin, ball clay, fire clay, bentonite, fuller* s earth, and
miscellaneous clay. Halloysite is included under kaolin in
Bureau of Mines statistical reports. Specifications of
clays are based on the method of preparation (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
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cn
WORLD PRODUCTION
«/ 350,000
Other
Norlt> America
12,767
South Am«rlco
12,000
U.S.S.R.
^/55,000
Wfl»I Gorraony
J/25.000
Japa n
«/ 28,000
Francs
«/16,000
Other Asia
•/ 37,000
Africa
i/10,000
Italy
it 17,000
OlnarCouttrlM
a/64,ooo
United Statei
57,235
Kaolin
4.201
Ball clay
630
Fire clay
8,054
B
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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 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
refractoriness 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 1454)
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
fuller1s earth clays are processed by blunging, extruding.
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drying, crushing, grinding and finally sizing according to
the requirements of its eventual use.
KAOLIN AND BALL CLAY (SIC 1455)
Kaolin is the name applied to the broad class of clays
chiefly comprised of the mineral kaolinite. Although the
various kaolin clays do differ in chemical and physical
properties the main reason for distinction has been
commercial usage. Both fire clay and ball clay are 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 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«A12p3.»6SiO_2) , albite
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(NaJ20»Al203_»6SiO.2) , and anorthite (CaO»Al2K)3»2SiO2) .
Specimens of feldspar closely approaching the ideal
compositions are seldom encountered in nature, however, and
nearly all potash feldspars contain significant proportions
of soda. Albite and anorthite are really the theoretical
end members of a continuous compositional series known as
the plagioclase feldspars, none of which, moreover, is
ordinarily without at least a minor amount of potash.
Originally, only the high potash feldspars were regarded as
desirable for most industrial purposes. At present,
however, in many applications the potash and the soda
varieties, as well as mixtures of the two, are considered to
be about equally acceptable. Perthite is the name given to
material consisting of orthoclase or microcline, the
crystals of which are intergrown to a variable degree with
crystals of albite. Most of the feldspar of commerce can be
classified correctly as perthite. Anorthite and the
plagioclase feldspars are of limited commercial importance.
Until a few decades ago virtually all the feldspar employed
in industry was material occurring in pegmatite deposits as
massive crystals pure enough to require no treatment other
than hand cobbing to bring it to usable grade. More
recently, however, stimulated by the often unfavorable
location of the richer pegmatite deposits relative to
markets and by the prospect of eventual exhaustion of such
sources, 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 rock which
contains little or no free silica, but does contain
nepheline (K2O*3Ka2p*HAi2O3»9SiO2) . 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.
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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 sequence continues with acid circuit
flotation in three stages, each stage preceded by 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 Al^OS.SiO^- Dumortierite contains boron, and
topaz contains fluorine, both of which vaporize during the
conversion to mullite (3&12O3.2SiO2).
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
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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
.rines are also principal sources of magnesium. It is the
third most abundant element dissolved in sea water,
averaging 0.13 percent magnesium by weight. Extraction of
magnesium from sea water is so closely associated with the
manufacture of refractories that it 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.
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Evaporites are deposits formed by precipitation of salts
from saline solutions. They are found both on the surface
and underground. The Carlsbad, New Mexico, and the Great
Salt Lake evaporite deposits are sources of magnesium
compounds. The only significant commercial source of
magnesium compounds from well brines is in Michigan,
although brines are known to occur in many other areas.
This form of mining is included in the clay, gypsum,
ceramics and refractory products report since it is closely
related to refractories manufacturing.
Selective open-pit mining methods are being used to mine
magnesite at Gabbs, Nevada. This facility is the only known
U.S. facility that produces magnesia from naturally
occurring magnesite ore.
Magnestie and brucite ore are delivered from the mines to
gyratory or jaw crushers where it is reduced to a minus 13
centimeter (5 inch) size. It is further crushed to minus
6.4 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).
When the source of magnesia is sea water or well brine, the
waters are treated with calcined dolomite or lime obtained
from oyster shell by calcining, to precipitate the magnesium
as magnesium hydroxide. The magnesium hydroxide slurry is
filtered to remove water, after which it is conveyed to
rotary kilns fired to temperatures that may be as high as
1850°C (3,360°F). The calcined product contains
approximately 97 percent MgO. The principal uses for
magnesium compounds follow:
Compound and grade Use
Magnesium oxide:
Refractory grades Basic refractories.
Caustic-calcined Cement, rayon, fertilizer,
insulation, magnesium metal,
rubber, fluxes, refractories,
chemical processing and manu-
facturing, uranium processing,
paper processing.
U.S.P. and technical Rayon, rubber (filler and
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grades
Precipitated magnesium
carbonate
Magnesium hydroxide
Magnesium chloride
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)
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 quarries.
Shales and common clays are used interchangeably in the
manufacture of formed and fired ceramic products arid are
frequently 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/m' (60-110 Ib/ft.'). 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«4SiOj2»H2O. The talc of highest purity is derived from
sedimentary magnesium 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 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
Al^o^«4SiO2*H2O. It is principally found in North Carlina.
Wonderstone is a term applied to a massive block pyro-
phyllite from the Republic of South Africa. The uses of
pyrophyllite include wall tile, refractories, paints,
wallboard, insecticides, soap, textiles, cosmetics, rubber,
composition battery boxes and welding rod coatings.
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During 1968 talc was produced from 52 mines in Alabama,
California, Georgia, Maryland, Montana, Nevada, New York,
North Carolina, Texas, and Vermont. Soapstone was produced
from 13 mines in Arkansas, California, Maryland, Nevada,
Oregon, Virginia, and Washington. Pyrophyllite was produced
from 10 mines in California and North Carolina. sericite
schist, closely resembling pyrophyllite in physical and
chemical properties, was produced in Pennsylvania and
included with 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 require 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 2.4 by 3.0 meters (4 by 8 by 10 ft) which are cut into
slices by gang saws with blades spaced about 7.6 cm (3 in)
apart. In the mining of block talc of crayon grade, a
minimum of explosive is used to avoid shattering the ore;
extraction of the blocks 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.
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Roller mills, in closed circuit with air separators, are the
most satisfactory for fine grinding (100 to 325 mesh) Of
soft talcs or pyrophyllites. For more abrasive varieties,
such as New York talc and North Carolina ceramic grade
pyrophyllite, grinding to 100 to 325 mesh is effected in
quartzite or silex lined pebble mills, with quartzite
pebbles as a grinding medium. These mills are ordinarily in
closed circuit with air separators but sometimes are used as
batch grindersf especially if reduction to finer particle
sizes is required.
Talc and pyrophyllite are amenable to processing in an addi-
tional microgrinding apparatus. Microgrinding or
micronizing is also done in fluid 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 1499)
Abrasives consist of materials of extreme hardness that are
used to shape other materials by grinding or abrading
action. Such materials may be classified as either natural
or synthetic. 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 A12O3_ 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.
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
77
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increasing competition with such artificial abrasives as
A12OJ3 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
SiO2, with minor additions of alumina, iron, lime, soda and
potash. The rpttenstone 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 (0.25
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 resulting sized product is
thickened, dried and packed for shipment.
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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«X2O3_»3SiO2 where the bivalent element R may be calcium,'
magnesium, ferrous iron or manganese; the trivalent element
X, aluminum, ferric iron or chromium, rarely titanium;
further, the silicon is occasionally replaced by titanium.
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 quarry methods. The ore
is quarried in benches about 10.7 m (35 ft) in height,
trucked to the mill and dumped on a pan conveyor feeding a
61 - 91 cm (24 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
79
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improve the hardness, toughness, fracture properties and
color of the treated garnets.
The only other significant production of garnets in the
United States is situated on Emerald Creek in Benewah
County, Idaho. This deposit is an alluvial deposit of
alamandite garnets caused by the erosion of soft mica
schists in which the garnets have a maximum grain size of
about 4.8 mm (3/16 in). The garnet bearing gravel is mined
by drag line, concentrated on trommels and jigs then crushed
and screened into various sizes. This garnet is used mainly
for sandblasting and as filtration media.
Approximately 45 percent of the garnet marketed is used in
the manufacture of abrasive coated papers, about 35 percent
in the glass and optical industries 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 SiO^ concentrations ranging from a low of 86 percent
(Nevada) to a high of 90.75 percent (Lompoc, California) for
the United States producers; the S±O2_ content of foreign
sources is somewhat lower. The remainder consists of
alumina, iron oxide, titanium oxide, and lesser quantities
of phosphate, magnesia, and the alkali metal oxides. In
addition, there is usually some residual organic matter as
indicated by ignition losses which are typically of the
order of 4 to 5 percent.
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The formation of diatomite sediments was dependent upon the
existence of the proper environmental conditions over an
adequate period of time to permit a significant accumulation
of the skeletal remains. These conditions include a
plentiful supply of nutrients and dissolved silica for
colony growth and the existence of relatively quiescent
physical conditions such as exist in protected marine
estuaries or in large inland lakes. In addition, it is
necessary that these conditions existed in relatively recent
times in order that subsequent metamorphic processes would
not have altered the diatomite to the rather more indurated
materials such as porcelanite and the opaline cherts.
The upper tertiary period was the period of maximum diatom
growth and subsequent deposit formation. The great beds
near Lompoc, California are upper Miocene and lower Pliocene
(about 20 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 by Nevada, Oregon and
Washington. Commonly, beds of ordinary sedimentary rocks
such as shales, sandstones, or limestone overlie and
underlie the diatomite beds; thus the first step in mining
requires the removal of the overburden, which ranges from
zero to about 15 times the thickness of the diatomite bed,
by ordinary earth moving machinery- The ore is ordinarily
dug by power shovels 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 baghouse where
they are separated into appropriate particle size groups.
The uses of diatomite result from the size (from 10 to
greater than 500 microns in diameter), shape (generally
spiny structure of intricate geometry) and the packing
characteristics of the diatom shells. Since physical
contact between the individual fossil shells is chiefly at
the outer points of the irregular surfaces, the resulting
compact material is microscopically porous with an apparent
density of only 80 to 260 kg/m3 (5 to 16 Ibs/ft3) for ground
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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,
crystallized 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 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
metamorphism 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 quartz, clays and iron sulfides.
Flake graphite, which is believed to have been formed by
metamorphism from sedimentary carbon inclusions within the
host rocks, commonly occurs disseminated in regionally
metamorphosed sedimentary rocks such as gneisses, schists
and marbles. The only domestic producer is located near
Burnet, Texas and mines the flake graphite by open pit
methods utilizing a 5.5 m (18 ft) bench pan. The ore is
hard and tough and thus requires much secondary blasting.
The broken ore is hauled by motor trucks to the mill.
Because of the premium placed upon the mesh size of flake
graphite, the problem in milling is one of grinding to free
the graphite without reducing the flake size excessively;
this is difficult because during grinding, the graphite
flakes are cut by quartz and other sharp gangue materials,
thus rapidly reducing the flake size. However, if the flake
can be removed from most of the quartz and other sharp
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minerals soon enough, subsequent grinding will usually
reduce the size of the remaining gangue with little further
reduction in the size of the flake. Impact grinding or 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 quartz,
mica, and other gangue minerals inadvertently become smeared
with fine graphite, making 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 1^99)
JADE
The term jade is applied primarily to the two minerals
jadeite and nephrite, both minerals being exceedingly tough
with color varying from white to green. Jadeite, which is a
sodium aluminum silicate (NaAlSi2O6) contains varying
amounts of iron, calcium and magnesium is found only in
Asia. Nephrite is a tough compact variety of the mineral
tremolite (Ca.2Mg5si8O22 (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 quarried, crushed,
dried and air classified prior to packaging. Chief uses are
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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 quite pure silica, called
"Novaculite", which are mined and processed into whetstones.
Most of the mining and processing is done on a very small
scale by individuals or very small companies. The total
production in 1972 of all special silica stone products
(grinding pebbles, grindstones, oilstones, tube-mill liners,
and whetstones) .was only 2,940 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 to avoid insufficient study of any one area.
Furthermore, the economics of each commodity differ 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
subcategories in this report.
Manufacturing Processes
Each commodity can be further subcategorized 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
subcategoriEation. 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
I
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
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TABLE TQ
Industry Gatfegortzatl on
Conaodity
Dimension Stone
Cruahad Stone
Construction
Sand «nd Gravel
Industrial Sand
Cypaca
Asphaltie Mineral*
Asbestos and
Wollastonite
Lightweight
Aggregate*
Hlca and Serlclte
1411
1422.1423,
1429. 1499
1442
1446
1492
1499
1499
1499
1499
Baxlta
Fluorspar
Salinas froa
Brine Lakes
Borax
rotaeh
Trona,
Sodium Sulfate
Bode Salt
Phosphate Bode
Sulfur (Fraaeb)
Mineral Pignents
T-lthlurq Minerals
Bentonite
Tire clay
fuller'a Earth
MO. filay
Feldspar
Kyanlta
Kagaealta
Shale & Coaoon
Clay, HEC
Tale Minerals Group
Natural Abraalvaa
DiatOBite
Graphite
Hlac. Minerals.
Not Claavhere
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
SubcntBgory
Ho further subeategorlsatlon
Dry
Wet
Flotation
Dry
Wet
Dredging, on-land processing
Dredge .wa):er plant Intake wafer
"»rjr tml. Bit FrocMtlnj
:teW Le«di1n»
Flotation' (acid and alkali)
Flotation (BF)
Dry
Dry, wet scrubbera
HKS
Bituminous llaestone
Oil Impregnated dlatowlte
dlleonlte
Asboatos, Dry
Asbeetoe, Vet
Vollastonit*
Parllte
Pusd.ee
VerBieulite
Dry
Wet ' .
Vet beasfleiatlon
either no clay T
general purpose
clay by-product
Vet Banaflclatlon
cor. gr> by-product
Dry
Ret
Flotation
Heavy sodie separation
flotation
Drying and Palletizing
No further subcategorizatlon
Ho further subcatigorizatloa
So further subcategorlzetloo
Kb further subcatagorizatioov .
Ho further subcategorlzation
Bo further aubcategorlzatlon
Flotation units
Non-flotation units
Anhydrite
Oa-shore
Off-ahore
Ho further eubcategorizetion
Bo further aubcategorizatlon
So. further subcategorizatlon
Ho furthar aubeaeegorization
Attapulglte
Kantoorillonite
Dry Kaolin mining and processing
Kaolin mining and vet processing
for high-grade produce
Ball clay - dry processing
Ball clay - vet proeaaaing
Feldspar vet processing
Feldspar dry processing
No furthar subcacegorlgetlon
No further subcocegorizatlon
Shale and comon clay
ApliCe
talc minerals group, dry proceaa
Tale einerale Croup, ore mining
fi washing
Tale minerals group, ore mining,
heavy radio and flotation ,
Garnet
Tripoli
No further subcategcritatlon
Ho further subcacegorlzatlon
Jade
Novocullto
86
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products usually result from different beneficiation
processes, and subcategorization is better applied there.
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 kkg/day. Setting
standards based on kg pollutant per 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 equipment in the
oldest facilities either operates on the same principle or
is identical to equipment used in modern facilities.
Therefore, facility age was not an acceptable criterion for
categorization.
87
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SECTION V
WATER USE AND 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
(U) 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, intermediate 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 quantities 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
89
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miscellaneous water use in this industry involves the use of
sprays to control dust at crushers, conveyor transfer
points, discharge chutes and stockpiles. This water is
usually low volume and is either evaporated or 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 equipment 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.
90
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(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 techniques. The machines are always
used with water, primarily to remove stone chips which
are formed by machine action.
(3) Wire sawing 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
91
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quarry can serve two or more processors (facilities 3304 and
3305). Also in a well defined, specialized producing area
such as Barrer 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 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 3034 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 equipment 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.
92
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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, 3304, 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 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/kkg of product (1,040 to 10,400
gal/ton). Water usage varies due to varying stone
processes, water availability, and facility attitudes on
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.
93
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to
MAKE-UP
WATER
r-WATER -i L RECYCLE
[(OPTIONAL ) | H8
1 I ¥
QUARRY
I
1 *.
1
1
1 1
1 J
SAW PLANT
1
1
POND OR
ABANDONED
QUARRY
MAKE
WA'
\
>UP
"ER
_ RECYCLE
I
FINISHING
PLANT
i
SETTLING
PONDS
FIGURE 16
DIMENSION STONE MhWG AND PROCESSING
-------
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, 1/kkg of stone
processed (gal/1000 Ib)
Saw Plant Finish Plant
4,460
unknown
unknown
unknown
16,600
unknown
9,800
7,350
unknown
unknown
100,000
unknown
unknown
unknown
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.
95
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CRUSHED STONE (SIC 1422, 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
(4) 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 quarries. 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
96
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FIGURE 17
QUARRY
VIBRATOR
FEEDER
•PUMI
PIT PUMPOUT
•PBOOUCT
CRUSHED STONE MINING AND PROCESSING
(DRY)
EFFLUENT RECYCLE
CRUSHED STONE MINING AND PROCESSING
(WET)
CONTIIT10NERS
WATER
OTHERS I
i WATER I
71
WATER
VENT
CRUSHING
SCREENIH3
OR
WET
GRINDING
• WET
MILLING
• .•
•
DRYING
WASTE VOTER
tVASTE WASTE
TO WASTE
TREATMENT
VKTES
CRUSHED STONE MINING AND PROCESSING
(FLOTATION PROCESS)
97
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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 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:
98
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Water Use
1/kkq of product (gal/1000 Ib)
Facility Non-contact Cooling Dust Suppression
1001 None None
1002 None None
1003 None None
1004 None None
1021 None 500
1022 8 None
1023 Unknown 16
1039 None Unknown
1040 None 13
121'2 None None
1213 None None
1215 290 8
1221 None None
1974 17 60
5640 None 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 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 volume of water is necessary to wash the finer
grades of material.
Washwater
Percent of 1/kkg of
Facility washed material product (gal/ton)
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
99
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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
as follows:
tabulation
Facility
1001
1002
1003
1004
1021
1023
1039
Raw Waste
Load, kg/kkq
of Product
40
50
40
150
80
20
20
Facility
1212
1213
1215
1221
1974
5640
5664
Raw Waste
Load, kg/kkg
of Product
270
30
10
130
22
10
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.
The water use for the three facilities is outlined as
follows. There are considerable variations in process and
mine pumpout waters.
Type
process
cooling
dust control
boiler
mxne
pumpout
1/kkg of product
1975 3069
(gal/ton)
151,000
(36,000)
22,700
(5,400)
1,510
(360)
unknown
4,900
(1,170)
850
(200)
1,400
(335)
6,600
(1,580)
none
1021
2,570
(610)
16,000
(3,800)
100
-------
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.
kq/kkcr of product (lb/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 404 of the Act, Permits for Dredged
or Fill Material.
10.1.
-------
CONSTRUCTION SAND AND GRAVEL (SIC 1442)
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 requiring extraction from a wet
pit or quarry 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 quarry is extracted via front-end loader, power
shovel or scraper, and conveyed to the processing facility
on conveyor belts or in haul trucks.
102
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FIGURE 18
o
co
SAND AND GRWEL MINING AND PROCESSING
(DRY)
too man
SAfO) AND GRAVEL MIMKW AND PROCESSING
(WET)
1
1
1
1
1
1
H-
—
1
CRUSH
SCREEN
1
—
"
-«s
TOW
BARGE
—
WET
PROCESSINS
PUNT
TUZNT «AtCT
SAND AKD GRAVEL tSSSHa AND PROCESSING
(HMS)
SAND AND GRAVEL MVSSiS AND
(DRE06ING WITH CN-LANO PROCESSING)
-------
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 require
the removal of clay fines and other impurities. The sand
and gravel deposits 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 impunities.
Impurities which are soluble or 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
larg'e 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.
(4) 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
104
-------
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.
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/kkq 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;
105
-------
Facility kg/kkcr of raw material flb/lOOO 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 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, 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 predominantly 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
106
-------
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 quarters 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;
Facility 1/kkg 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:
107
-------
Dredge
1009
1010
1011
1046
1048
1051
1052
At Dredge
kg/kkg of feed
(lb/1000 Ib)
460
none
none
none
none
250
180
At Land Facility
kg/kkg of feed
(lb/1000 Ib)
100
400
150
110
120
60
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 tow-barges 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 scrubber 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
108
-------
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.
109
-------
INDUSTRIAL SAND (SIC 1446)
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
subcategori es:
(1) Dry Process
(2) Wet Process
(3) Flotation Process
(4) Acid Leaching 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 sufccategory. 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 beneficiation.
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.
110
-------
FIGURE 19
DIC
COLLE
SANDSTONE
QUARRY
BEACH
DEPOSIT
— u,
DRY
r-*-
i
T
;TIOH
ocnY)
.... m.fr SCREEN
WASTE WASTE
FINES FINES
LEGEHD:
ALTERNATE
' ROUTE
INDUSTRIAL SAND MIMIN3 AND PROCESSING
(DRY).
r
WET PIT
A
1
t i
i j
L L
H*
SCREEN
r*
j 1
0J SOLID
WASTE
RECYCLE VOTER
DESLIMING
GEWATERING
1
1
*
THICKENER
OR
CLARIFIES
1
f *
SETTLIHS FONT
CLASSIFYING [— «» PROOUCT
"I "f» 1
1 i
if MILL -J
OI__FU>CCULAT1NS
Mur
INDUSTRIAL SAND MINING'AMD PROCESSING
(WET)
HP FLOTATION PROCESS -HF
ALKAL1KE FLCTATIOH PROCESS-CAUSTIC
FLOTATION AGENTS.
„, '.
'
SULFURIC ACID
WAI
_» FELDSPAR
CO-PRODUCT
IRON-PFA1IH3
SOLID WASTE
INDUSTRIAL SAND MINING AND PROCESSING
(FLOTATION PROCESSES)
m
-------
Wat r
Sand
ro
Magnetic
Sand
Impurities
to stockpile
Vent
Glass
Sand
Silo
To Lagoons
INDUSTRIAL SAND - ACID LEACHING PROCESS
-------
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 baghouses 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.
113
-------
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:
(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.
114
-------
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.
Facility
Process
Recycle
process
Discharge
Scrubber
(recycle)
Total
1101
25,400
none
none
1019
2,580
1/kkq of product
1103
1980
23,200
none* none
none
50
(10)
5691
27,300 8,400
6,830 5,250
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 kq/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.
115
-------
ACID LEACHING PROCESS
The acid leaching or feldspathic sand process is principally
designed for the removal of iron to the levels acceptable to
the glass industry. This process consists of initial
drying, screening for removal of oversize particles, initial
iron removal using five roll high intensity magnetic
separators, followed by wet process acid leaching in special
vessels for complete inundation in a strong hydrochloric
acid or sulfuric acid solution. This is followed by
processing over a vacuum filter for leach solution recovery,
washing, dewatering, and then final drying in a rotary
parallel flow dryer before storage and delivery to the
customers.
The water use at facility 3215 is 13.2 liters/kkg (55
gal/ton) of product. The raw waste load of the wastewaters
from this plant's acid leaching process is given below. The
pH range from 1-2.
kg/kkg (Ib/ton) of product
iron (as Fe203) 1.25 (2.5)
TDS ~~ 8.01 (16.0)
R203 1.96 (3.92)
A12O3. 0.710 (1.42)
116
-------
GYPSUM
Although some underground mining of gypsum is practiced,
quarrying 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)r the industry was divided into the following
subcategories:
(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
quarrying, 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
quarries 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.
117
-------
FIGURE 20
VENT
MINE
QUARRY
*
«T PUKPOUT
PRY
OUST
COLLECTOR
Ji
1
PRIMARY
__» AND
SECONCARY
CRUSHING
GRINDING
f
•PRODUCT
6YPSUM MINING AND PROCESSING
(DRY)
RECYCLE
WATER
RECYCLE
WATER
RECYCLE
WATER
TO PROCESS
GYPSUM MINING AND PROCESSING
(HM3)
» PRODUCT
118
-------
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 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 beneficiation.
119
-------
ASPHALTI.C MINERALS (SIC 1499)
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 470 - 1,800 (110-430)
drinking and
irrigation 2,300 (550)
120
-------
FIGURE 21
SURFACE
1
OVER3USDEM
(SOLID V/ASTE) •
BITUMINOUS LIMESTONE MINING AND PROCESSING
VENT
MAKE-UP WiTER
SURFACE .
MINING
OIL IMPREGNATED DJATOMITE MINING AND PROCESSING
WET
SCRUBBER
SOLIDS
SEPARATOR
SCREEN
COLLECTOR
CENTRIFUGE
-
FLOTATION
1 1
— *
DRYER
PONO
'J'LIb \WSTEI
BCCYCCe
TO PROCESS
GILSONITE MIMING AND PROCESSIN3
121
-*UCT
-------
ASBESTOS AND WOLLASTONITE
ASBESTOS (SIC 1499)
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, DRY 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 15X 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 (4
gal/ton) .
122
-------
FIGURE 22
KM!
WATER—H
WASTE
FINES
PRODUCT
ASBESTOS MINING AND PROCESSING
'DRY)
MAKE-UP
WATER
VEMT
RECYCLE
r
1 CRUSH
QUARRY CJ AMD 1M ^ CLAI
I , SCREEN
SIFY
I i
r
DEWATER
WASTE DUMP
i
FILTER
\
I
POND
FIL
T
VENT
DRY
AS3ESTOS MINING AND PROCESSING
(WET)
123
-------
ASBESTOS, WET PROCESS
The only facility in this subcategory, 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
(50% 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 84
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
quality 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).
124
-------
MINE
[•MMM^jgl
CRUSH
AND
SCREEN
_— Se>
DRY
CRUSH
AND
SCREEN
MAGNETIC
SEPARATORS
MILL
AND
CLASSIFY
PRODUCT
WASTEPILE
ro
en
FIGURE 23
WOLLASTONITE 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 accumulatesg 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.
126
-------
FIGURE 24
VENT
PRODUCT
..EXTONDED
"^PRODUCT
DUST WA TE
FINES FINES
TO TO
LAND LAND
DISPOSAL DISPOSAL
PERL1TE MINING AND PROCESSING
1 SURFACE
MINING
1
SCREENING
AND
CRUSHNS
.PRODUCT
PUMICE MINING AND PROCESSING
MAKE-UP VOTES
VERM1CULITE MINING AND PROCESSING
127
-------
VERMICULITE
The mining 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 24 is a flow diagram showing the mining and proces-
sing 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.
128
-------
flotation and drying operations. This stream consists of
mineral solids, principally silicates such as actinolite,
feldspar, quartz, and minor amounts of tremolite, talc, and
magnetite (1,600 kg/kkg product)»
129
-------
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 bragging. 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
130
-------
FIGURE 25
MINE
LEGEND:
SCREEN
AND
' STORE
BAG
HOUSE
i ,
<
DRY
t
FLAKE AND
SCRAP MICA
*
MILL,
.—&
SCREEN
1 1
J WASTE
FLUID
ENERGY
KILL
_^
«ea
»— e»
CLASSIFY
•O'TROOUCT
-— —B-PTODUCT
i tffPROOUCT
...—^.PRODUCT
SCRAP AND FLAKE KIM
vasTE
MICA MINING AND PROCESSING
(DRY) .
WATER RECYCLED
TO GRINDING 1/ILL3
MICA MINING AND PROCESSING
(WET)
LEGEND;
—— FLsnsraN
— — — SPI.TAL
MICA MINING AND P:\OCESSING
(FLOTATION C',1 SPIRAL SEPARATION 1
131
-------
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 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 requires 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.
132
-------
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:
Process Water Used
Facility
2050
2051
2052
2053
2054
2057
2058
Facility
1/kkq of product
95,200
240,000
•825,000
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 (qal/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 (16,700)
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:
133
-------
Clay, slimes, mica fines and sand wastes
Facility kg/kkg of product (lb/1000 lb)
2050 600
2051 14,400
2052 2,600
2053 4,000
2054 4,700
2057 2,900
2058 6,300
134
-------
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
techniques 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. Prom 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 -4" barite
product is sent to the stockpile. The +3/4 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
135
-------
FIGURE 26
CRUSHING
CIRCUIT
SOLID
VftSTE
BARITE MINING AND PROCESSING
(DRY GRINDING PROCESS)
IUKE-UP WATER AND RECYCLED WATER
FROM THE TAIUNOS PONO
I
PRODUCT
1
BREAKER
-«.
SOUB W4STE
\
LOB
WASHER
-»
WASTE
TO
SFTT1 IKS WHO
I
TROMMEL
SCREEN
SOLD
(TASTE
— <=
DEWATER
—
I
JIGS
4e
iETTUNG POND
BARITE MINING AND PROCESSING
(WET PROCESS)
WATER
TO
SETTU.W3 POW
ORE-
WATER
t
cnusH
AND —
WASH
OLIO SLIWE
ASTE SALVASE
RECYCLED
WATER
9 JIG
GRAVEL SLIM
TO SALX'A
WSSTE
J
1
••£
WATER
MILL,
CLASSIFY,
AND
COHDITION
RECYCLED
TO JIO
STEAM WATER
iKE/-ENTS
1 I' i
, FLOTATION ' THiCK
SECTION ~** CIR(
1 1
TAILM3S KK>
FILTRATE
'1
FILTER,
ENINS _— DRY
:urr ^^ AND
COOL
JIGGED
PRODUCT .
•'PRODUCT
IND CONOmONtNO
BARITE MINI,\'G AND PROCESSING
(FLOTATION PROCESS)
136
-------
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 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 given as follows:
water consumption in 1/kkg
of product (gal/ton)
barite recovery sanitary and
Facility from feed (%> process water misc. usage
2011 63 62,600 (15,000) 650 (150)
2012 63 140,200 (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 gal/ton) because only 30-40 percent of the
ore goes 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
137
-------
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.
The major 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:
I/day (gal/day)
Facility 2010 2014 2019
Mill tailings 530,000 660,000 4,730,000
(140,000) (173*500) (1,250,000)
Washdown water 265,000 110,000
from mill (70,000) (29,000) unknown
Spent brine from 19,000 •
water softening (5,000)
operation
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:
138
-------
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 6 back flush —•
&rinse water used
in water softening
Misc. housekeeping —•
2014
792,000
(208,960)
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)
139
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FLUORSPAR (SIC 1U73)
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:
140
-------
FIGURE 27
CRUDE ORE
WATER
OEWATER1NG
SCREEN
1 i
"1
1
1
I
.
FLOTATION
FEED
CRUSHINS
AND
RECYCLE
WATER
CRUSHING FOR
AND RECYCLE
RECYCLE
FLOTATION
FEED
LEGEND:
OVfRSIZE
UNDERS/ZE
FLUORSPAR .MiNiM-TAND PROCESSING
(HMS PROCESS)
—-*"PROOUCT
ZINC BY-PRODUCT
WATER
FOR
RECOVERY
FLUORSPAR MINING AND PROCESSING
(FLOTATION PROCESS)
141
-------
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
selectivity 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:
142
-------
I/day (mqd)
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
CO. 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 (gal/ton)
11,900
(2,860)
9,540
(2,290)
20,200
(4,840)
19,100
(4,580)
0
1,144,500
(0.302)
21,030
(5,040)
0
The process raw wastes in this subcategory 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 CaFJJ, 20-25 percent CaCO3_,
25-30 percent SiOJ2, and the remainder is primarily shale and
clay. The average values of the raw wastes are:
kq/kkg of product (lb/1000 Ib)
2000 2001 2003
flotation tailings
1,800
2,000
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
143
-------
the acid facility effluent. The combined effluent stream
has been 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 FLUORSPAR 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
(2094). 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 2084).
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 2084 and 2087. What water
there is in these mines drains underground and eventually
enters mine 2083. It has been 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 40 percent, respectively,
of the mine discharge water is used at the mills. The
remaining drainage is then discharged.
144
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SALINES FROM BRINE LAKES (SIC 1474)
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, 74 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 (4.32 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 liquor high in potassium chloride and
145
-------
borax. As the concentration proceeds, large amounts of salt
(NaCl) and burkeite (Na2CX>3, Na2SOJ*) 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 soda ash
(Na2CO.3) , salt cake (Naj2SO£) , 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
crystallizers 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
(4.32 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 33,600,000 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.
146
-------
FIGURE 28
m.r» i
— :RYSTALUIE .
„ MLTtR ""*
...I * ., ,,.
CRYSTALLIZE
flLUR
'
i T t
WASH, nOTAT,™
DISSOLVE ~* FLOTATION
i
CAMM WOWK— *
CARBOHATION
UKK l«Nt-»
(«ura uaiw
M cure mum
_5«3Tt UWM
fMOUCT
VttT
T t
.. ^ FILTER,
^^ YWSH
1 i T T
CRYSTALLIZE ~* FILTER — «« WMII — • OIW — «"MMX HMJUtT
1
T
CRYSTALL'Jt, _,.. H-'-f, .tononnni mMn
. ' FILTER CALCINE p«»c«
MINERALS RECOVERY FROM SEARLES LAKE
WATER
1
WASHING
DRYING
1
« TO LAKE
' 1
1 EVAPORATION .„„ ,, .. ^ BD^N
j PONDS PROOUCT
, - _ ,,.,», fi-"l
WATER mmXT
f
DRY'fNG ' PROOUCT
TO LAKE
MINERALS RECOVERY AT GREAT SALT LAKE
•"NE jri
FROM WELLS W
PRELIMINARY
EVAPORATION
•1
— O
I-'W UME SOU ASH VENT
« ill
REACTION
POND
"*
SECONDARY
EVAPORATION
1 !
-~
REACTOR
AND
FILTER ;
i
-
FILTER
"giOHlj SOCIDS Ml(OH),
(SOLID VUCTE) (NoCI, KCI) (SOLID WASTE)
TO STORAGE
1 - , LIOUOB
LITHIUM
— ^CARBONATE
PROOUCT
LITHIUM SALT RECOVERY
NATURAL BRINE, SILVER PEAK OPERATIONS
147
-------
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.
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 substances as constituents along with
minor amounts of materials present in lake brine 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 14,500 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
148
-------
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 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/kkq of product (gal/ton)
Process brine 1,500,000 (360,000)
Process washout water 36,800 (8,500)
149
-------
BORAX (SIC
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 liquor), 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.
150
-------
WATER
RECYCLE MOTHER LIQUOR
BORAX _ni ;ii&
ORE
1 1
CRUSHER
— f»
DISSOLVER
~~&,
THICKENER
— >
CRYSTALLIZER
_i T_
CENTRIFUGE
—«B
DRYING
AND
SCREENING
en
WASTE WTER
•^•PRODUCT
FIGURE 29
BORATE MINING AND PROCESSING
-------
POTASH (SIC
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.
(4) 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 84 percent of the U.S.
production 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
152
-------
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 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, K2Mgj2 (SOjy.3, and
is intermixed with sodium chloride. This ore is mined,
crushed, and the sodium chloride is removed by 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:
Facility
input:
fresh water
brine
1/kkg of product
5838
(gal/ton)
5843
6,420 (1,540)
not known
1,750 (421)
3,160 (760)
use:
process contact
cooling
boiler feed
consumption:
34,600 (8,300)
0
0
11,900 (2,900)
0
205 (50)
153
-------
FIGURE 30
_ BWIJE RKTCLE
* T ~
| FUOT
I i ,
CRUSH CESUV2
r.Kti — =J AN3
GfiMU SEFARATE
— C'
>TION
\
FLOTATION
.1 I
BKW3 SLWci
TO 'iWSTE TO
OB W»STE
TORECYO£
—a- DEVM
1
TA>L»»S
WASTE . •
AI.'O
craiE
1 '»«rncoucr
lEgEMO;
ROUTB
POTASSIUM CHLORIDE MINING AND" PROCESSING FROM SYLVINITE ORE
POTASSIUM
CHLORIDE ~
UUKMMTEORE
«SSTE tun
'.LANGBBNITE'MINING AND PROCESSING
«»TEB
SYLVINITE
DEPOSIT
EVAPORATION
PONDS
FLOTATION
SEPARATION
DRYING
SODIUM CHLO'tCE
. SOLID WASTE
POTASH RECOVERY BY SOLUTION MINING OF SYLVINITE
154
-------
process waste
boiler blowdown
6,420 (1,540)
0
4,710 (1,130)
205 (50)
Water use at langbeinite ore processing facilities is shown
as follows:
Facility
input:
fresh water
1/kkq of product (gal/ton)
5813 5822
8,360 (2,000)
4,800 (1,200)
use:
leaching and washing
cooling
consumption:
process evaporation
process waste
cooling water evapora-
tion
5,000 (1,200)
30,000 (7,200)
0-1,670 (400)
0-1,670 (400)
6,700 (1,600)
4,800 (1,200)
0
4,800 (1,200)
0
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:
Facility
wastes:
clays
Nad (solid)
NaCl (brine)
KC1 (brine)
MgSO4
K2SO4.
Facility
kg/kkg of product (lb/1000 Ib)
5838 5843
75
3,750
1, 400
75
640
440
5813
235
2,500
1,000
318
75
0
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
155
-------
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 K2SO£ recovery is:
potassium 3.29%
sodium 1.3%
magnesium 5.7%
chloride 18.5%
sulfate H.9%
water 66.1%
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/JcJcg (2,800 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.
156
-------
TRONA (SIC 1474)
All U.S. mining of trona ore (impure sodium sesquicarbonate)
is carried out in Sweetwater County, Wyoming, in the
vicinity of Green River. 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 (4,400,000 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/kkg soda ash product.
157
-------
FIGURE 31
wvomwtn HT»XE-»
PRECIPITAT
FILTER
VENT
STOCKPILE -•
ASEA cssx
,
RUNOFF
WATER
COU-ECTt
PONBS
SCRUBBER
OR
PRcCPfTATOR
1
WISH -•
AST
W£
1
CALUNE
[
— f
1
UUE-IF wren
E. •
DISSOLVE
EETUE.-
CLARIFY
AND
FILTER
JL
Ko-2«)_r*"
MX
I T
VttTEft VAPCR "TO *
WS30N
CAREOM B/'DOTTE.
— l«ww™*-*eRWniiS-
t»N. SPENT CAS9C1
^ AND FtTSS AID
!
EVAPORATION PONDS |
SCRUBSE
PRECIPITA1
CILEII FEED
• ajfIMME-.S|««
R
W
1000 SCO*
r ^ASH necuet
TRONA ORE PROCESSING
BY THE MONOHYDRATE PROCESS
..BOO SOOA
ASHPBOOCT
TRCNA ORE PROCESSING
BY THE SESQUICARBONATE PROCESS
158
-------
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.
Raw wastes frbm 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 1,140 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 con-
taining 2,160 kg/day (4,750 Ib/day) of total solids, prin-
cipally 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 kq/kkcf of ore (lb/1000 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
159
-------
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
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 (mgd) 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)
net flow 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.
160
-------
SODIUM SULPATE (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 step-
wise 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.
161
-------
STEAM VENT
SODIUM
SULFATE
BRiNE
WELL
ro
SETTLING
1
I
COOLING
AND
SETTLING
LIQUOR
TO
EVAPORATION
POND
DEHYDRATION
PRODUCT
(ANHYDROUS)
RGURE 32
SODIUM SULFATE FROM BRINE WELLS
-------
ROCK SALT (SIC 1U76)
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:
(D
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.
(H) 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.
163
-------
ROCK SALT
UNDERGROUND
MiWiWG
LEGEND:
UNDERCUTTING,
DRILLING
AND
BLASTING
MULTIPLE
STAGE
CRUSHING
AND
SCREENING
en
ALTERNATE OR
OPTIONAL PROCESS
UNDERGROUND
11
PRODUCT
CRUSHING
AND
SCREENING
—
PRODUCT
PREPARATION
AND
PACKAGING
--•ffi»PRODUCT
SURFACE
FIGURE 33
ROCK SALT MINING AND PROCESSING
-------
PHOSPHATE ROCK (SIC 1475)
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.
165
-------
Facility 4022 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 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 unique 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
follows:
as
Facility 10^ 1/dav
4002
4003
4004a
4004b
4005a
4005b
4005c
4007
4015
4016
4017
4018
4019a
4019b
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
mqd
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
1/kkq 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
166
-------
FIGURE 34
SCREEN
AND
WASH
MINE
•r .
L*
SCREEK
RECYCLE
WATER
"L *
uj
SLIMES
REMOVAL
f°\_
1
|
1
1
THIC..£NER
CONDITIONER,
FLOTATION
(FKMAFW)
1
TAILK
DISPOSE
,_l_,rr! PlP'-ftll
i ;
WATER
4
CCNCITICNcRj
— 8» FLOTATION
(SECONDARY)
...1: :i
1
GSTO
\L FOND
i
TAILINGS TO
•DISPOSAL POND
r
_J
VENT
FILTcR
AND/OR
DRYER
SUMES TO SETTUTW POND
PHOSPHATE MINING AND PROCESSING
EASTERN
r
CRUSH
J
MINE RECYCLE W4TD
'I *
1
LEGEND:
M.TERNXI
SCRUBBER
re mure
RECYCLE
'' '
? MILL m^a, SLIMES WATER
K<0 ^ REMOVAL |
pfr CLASSIFY K—i ^
J 1 [_ CONDITiOKt
1 FLOTATK3J
1
1
| 1 I
J THICKENER
I ,
1
1
u
RLT
r.
,
r
VENT
f
DRYING
J
ER
'1
u
CALCINING
» PRODUCT
SLIMES AND TAILINS3 TO SETTLING PONB
PHOSPHATE MINING AND PROCESSING
WESTERN
167
-------
4019c
4020a
4020b
4022
255.9
257.4
174.1
67.6
68
46
81,100 19,400
21,300 5,100
32,200 7,700
11,200 2,700
N/A
80
85
66
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
quantities follow:
their
kg/kkg (lb/1000 Ib) of product
Mine Pit Dust Scrubber
Facility Slimes
4002
4003
4004a
4004b
4005a
4005b
4007
4005c
4015
4016
4017
4018
4019a
4019b
4019c
4020a
4020b
4022
790
370
information
information
1180
1160
no (a mine
1050
1000
1300
860
770
900
1290
1030
1330
1710
Tailings
1380
840
not available
not available
900
1290
only)
1520
1000
1300
2440
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.
168
-------
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.
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. Subsequent 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 4030 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 ±s 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:
169
-------
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)
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 Ib) of Product
4006 1000
4008 580
4025 1010
4023 500
4029 484
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.
170
-------
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, down 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.
171
-------
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-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
CaCO3) which originates from the water purification
operation. The raw waste loads are presented as follows:
Waste Material
at Facility
Water softener
sludge
kg/kkg of product (lb/1000 Ib)
2020 2095
9.6
15.3
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.
172
-------
TREATMENT
CHEMICALS
RAW
WATER
oo
SEA WATER
I
LEGEND:
WAI
TREA
PL/5
1
BLOW
TR
TiNG
^NT
ft
1
BOILERS
r ! 1
DOWN BLOVy
1
t
L.
1
^HH
i
DOWN
^
—&*
\
i
HEAT
EXCHANGERS
SULFUR fc
& ^ DtPOSI! —••»•»•
1 i
i |
t
1 * '
?
SLOWDOWN
\
HEATER '•
. -i ^ ^ ^.Li 1
MOLTEN
SULFUR
PRODUCT
ANHYDRITE DEPOSITS
CONVENTIONAL SALT DOME OPERATION
PROPRIETORY SALT DOME OPERATION
BLEED WATER
TO TREATMENT
AND DISPOSAL
R6URE 35
SULFUR MIMING AND 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
quantity 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
(MGD)
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 sulfide chloride
mg/liter mq/liter mq/liter
<5
<5
<5
<5
39
600 -
1,000
600 -
1,000
600 -
1,000
600 -
1,000
84
1,050
38,500
31,500
59,200
14,600
25,400
23,000
(1) Includes 69,400,000 liters per day (18.3 MGD)
seawater used in final dilution and treatment step.
of
(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.
174
-------
The sludge from the water treating operations varies in
chemical composition and quantity depending on the type of
water used in 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
bleedwater 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.
175
-------
MINERAL 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.
176
-------
OVERS
i
CRUSHER
ROTARY
DRYER
ROLLER
MILL
AIR
CLASSIFICATION
MINE
STEAM
DRUM
DRYER
SOLID
WASTE
•PRODUCT
•«» PRODUCT
FIGURE 36
MINERAL PIGMENT MINING AND PROCESSING
-------
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 quartz 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 .wast^e from the process being
discharged as a slurry to the settling pond or stored as dry
solids is directly related to the quantity 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:
178
-------
SPODUMENE
ORE (OPEN «•
PIT MINING)
CRUSHING'
AND
GRINDING
SLIMES
REMOVAL
SPODUMENE
FLOTATION
LEGEND:
ALTERNATE OR
OPTIONAL PROCESS
•<£>
BY-PRODUCT
FLOTATION
AND
CLASSIFICATION
SLIMES-TAILINGS TO SETTLING POND SOLID
(OVERFLOW RECYCLED TO PROCESS ) WASTE
FILTER
SPODUMENE
•CONCENTRATE
PRODUCT
DRYER
SPODUMENE
••^CONCENTRATE
PRODUCT
• BY-PRODUCT
MAGNETIC
SEPARATION
CERAMIC
J3RADE
SPODUMENE
PRODUCT
LOW IRON
PROCESSING
LOW IRON
••OSPODUMENE
PRODUCT
RGURE 37
SPODUMENE MINING AND PROCESSING
(FLOTATION PROCESS)
-------
Facility 4001
Waste Material
Slimes
Tailings
Mine water
Facility 4009
Waste Material
Slimes 6 tailings
Mine water
Scrubber slurry
Source
flotation
dewatering
mine pit
Source
flotation
mine pit
Low iron
process
kg/kkg of feed
(lbs/1000 Ib)
100
unknown
(intermittent, unknown)
kg/kkg of feed
(lbs/1000 lb)
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 4001
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)
180
-------
Facility 4009
1. Water Usage
Process
Non-contact
cooling
Boiler
Sanitary
Total
1/kkcr
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)
181
-------
BENTONITE (SIC 1452)
Bentonite is mined in dry, open pit quarries. After the
overburden is stripped off, the bentonite ore is removed
from the pit using bulldozers, front end loaders, and/or pan
scrapers. The ore is hauled by truck to the processing
facility. There, the bentonite is crushed, if necessary,
dried, sent to a roll mill, stored, and shipped, either
packaged or in bulk. Dust generated in drying, crushing,
and other facility operations is collected using cyclones
and bags. In facility 3030 this dust is returned to storage
bins for shipping. A general process flowsheet is given in
Figure 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.
182
-------
00
CO
CRUSHER
WFMT
OPEN PIT
QUARRY
A
i
i
i
!
l riL
i t
DRYER
1
1
SCREENS
,,| ROLL MILL „ STORAGE
» ROLL MILL M BINS
i A
l 1
__._J i
l
_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
3047) 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.
184
-------
00
Ol
OPEN
PIT
CRUSH
5
I
1.
!
1
SCREEN
1
I
f
CALCINE
REFRACTORY
OPERATIONS
—.—.—. — — ._ — •» PRODUCT
PRODUCT
FIGURE 39
FIRE CLAY MINING AND PROCESSING
-------
FULLER'S EARTH (SIC
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.
ATTAPOLGITE
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/kkg of product
(gal/ton)
3058 3060
Intake:
Make-up 460 (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)
186
-------
FIGURE 40
OPEN -
PITS
VATP)—
CRUSHING
SCREENING
•
-&, PUB _
MILL
«a.iA — » SC
VENT
t
_-; ROTARY
DRYERS
t
8
RUE
^
BE
I
TO
RS
ND
WTEI
1
POND
1
KILN
M
I
j
-i
Lh
EFFLUENT
EFFUSNT
4CfERW7C PRQCC33 ROUTES
FULLER'S EARTH MINING AND PROCESSING
(ATTAPULGITE)
PRODUCT
PRODUCT
. LEGEND:
*LTEfiNATE MR
\
e MR
TREATMENTS
KC
1
""N
f .
1
J.
V
1
BAG
COU.EC1
j
roRS
Mil
SCR
1
' - '" ""H
t r '
EEN . ROTARY
^t. DRYER .-J
• AND
COOLER
CLAY SLUDGE
TO MIME
OUST AND FINES TO MINE
EARTH MINING AND PROCESSING
(MONTMORILLONITE)
187
-------
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 1140 I/day (300 gpd).
Water is used in processing only in dust scrubbers. Typical
flows are:
1/kkg product (gal/ton)
Facility 3059 3072 3073 3323
Dust Scrubbers 1,930 (460) 500 (120) 143 (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.
188
-------
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:
189
-------
FIGURE 41
.TRUCK
DRYING
AND
CLASSIFICATION
SOLID
WASTE
• PRODUCT TO SHIPPING
—»»TO ON-SITE REFRACTORY
MANUFACTURING
EFFLUENT
DRY KAOLIN MINING AND PROCESSING
FOR GENERAL PURPOSE USE
WATER
OPEN
PIT
PIT
FtAIPOUT
ZINC
HYOROSULFITE
DEGRITTING
AND
CLASSIFICATION
I
WATERBORNE
TAILINGS TO
SETTLING POND
OR BY-PRODUCT
RECOVERY
BLEACHING
_,_, AND/OR
T^ CHEMICAL
| TREATMENT
1
L
1
_JL,ME_J
|f
POND
EFFLUENT
KAOLIN
i
BULK
SLURRY ~~
• PRODUCT
70%
SLURRY
PRODUCT
WET KAOLIN MINING AND PROCESSING
FDR HIGH GRADE PRODUCT
190
-------
1/kkq 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)
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:
kg/kkcr product (lb/1000 Ib)
Waste Material 3024 3025
zinc 0.37 0.5
dissolved solids 8 10'
suspended solids 35 100
The dissolved solids are principally sulfates and sulfites
and the suspended solids are ore fines and sand.
191
-------
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/kkq 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.
192
-------
PITS
SHRED
HOT
AIR
CYCLONES
"„*
BAG
HOUSE
i r t
STOCKPILE
HAMMER
MILL
AIR SEPARATOR
1
J-GEND:
UD
> ALTERNATE PROCESS ROUTES
I
ROTARY
DRYER
BAGGED
PRODUCT
BULK
PRODUCT
•i —'WATER
SCRUBBERS
CHEMICALS-
WATER-
BLUNGER
POND
SCREEN
^ SLURRY
PRODUCT
SOLID WASTE
(LIGNITE, SAND)
EFFLUENT
FIGURE 47
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 subcategory.
FELDSPAR - FLOTATION
This subcategory of feldspar mining and processing is
characterized 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
194
-------
FIGURE 43
QUARRY
entiQucoQ
BALL
MILLS
AIR
CLASSIFICATION
B PRODI-IT
FELDSPAR MINING AND PROCESSING
(DRY)
WATER
WASHER
SCRUBBER
WATER
CLAS
CON
FL<
(3REF
\
WA!
SLUR
T
PO
\
IR
SOL
WA!
TE
R1ES
0
ND
FLOTATION
AGENTS
SIFIC/
3ITI»
AND
3TATI
'ETIT
t
IN
ID
>TE
moN,
iiNQ,
ON
IONS)
1
VENT
DEWATERING
DRYINS
WASTE
WATER
BALL
MILL
I
MAGNETIC
SEPARATION
1
•— »• PRODUCT
— S»PRODUOT
BY-PROOUCT
MICA FrtOM
^BY-PROOUCT
SANO FROM
THIRD FLOAT
FELDSPAR MINING AND PROCESSING
(WET)
195
-------
crushing steps, and some recycle of water in the fluoride
flotation step is practiced at facility 3026.
Total water use at these facilities varies from 7,000 to
22,200 1/kkg of ore processed (1,680 to 5,300 gal/ton).
Most of the process water used in these facilities is
discharged. Some water is lost in tailings and drying.
This is of the order of 1 percent of the water use at
facility 3065. The use of the process water in the
flotation steps amounts to at least one-half of the total
water use. The water used in the fluoride reagent flotation
step ranges from 10 to 25 percent of the total flow
depending on local practice and sand-to-feldspar ratio.
Only two of these five facilities use any significant
recycling of water. These are:
facility 3026 - 17 percent of intake (on the
average)
facility 3067 - 10 percent of intake
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:
kq/kkg of ore
processed (lb/1000 Ib)
facility ore tailings and slimes fluoride
3026 270 0.22
3054 410 0.24
3065 260 0.20
3067 530 est. 0.25
3068 350 est. 0.25
196
-------
FELDSPAR - NON-FLOTATION
This subcategory of feldspar mining and processing is
characterized by completely dry operations at both the mine
and the facility. Only two such facilities were found to
exist in the U.S. and both were visited. Together they
represent approximately 8.5 percent of total U.S. feldspar
production. However, there are two important elements of
difference between these two operations. 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.
197
-------
KYANITE
Kyanite is produced in the U.S. from 3 open pit mines„ two
in Virginia and one in Georgia. In this study two of these
three mines were visited, one in Virginia, and one in
Georgia, representing approximately 75 percent of the U.S.
production of kyanite.
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 1540°-1650°C (2800-
3000°P) in a rotary kiln. A general process diagram is
given in Figure 44.
Water is used in kyanite processing in flotation,
classification, and slurry transport of ore solids. This
process water amounts to:
1/kkcr 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 kyanite {lb/1000
facility 3015 tailings 2,500
facility 3028 tailings 5,700
198
-------
10
10
WATER
u/AY^D nEGYCLC ui
QUARRY
1 1
CRUSHING
i
1
CLASS
FLO"
FLOTATION
REAGENTS
n
IFICATION,
TIONING, —
FATION
i
VEKT
.. nuviwr -A. MAGNETIC r-
"* ORYING * SEPARATION
UNDERFLOW 1
TAILir
POND
res 1 SCALPINGS
TO WASTE
KYANTTE
ROTARY fc MULLITE
KILN ^ PRODUCT
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 (3/4 in) in a cone crusher. The raw
materials are dry ground in two ball mills that are in
closed circuit with an air classifier. The minus 65 mesh
product from the classifier is transported by air slides to
the blending silos. From the silos the dry material is fed
to pug mills where water and binding materials are added.
From the pug mills the material is briquetted, dried, and
stored in feed tanks ahead of rotary kilns. The oil or
natural gas fired kilns convert the magnesite into dense
magnesium clinker of various chemical constituents,
depending upon the characteristics desired in the product.
After leaving the kiln, the clinker is cooled by an air
quenched rotary or grate type coolers, crushed to desired
sizes, and stored in large storage silos for shipment.
In the light burned magnesite circuit, minus 1.9 cm (3/4 in)
magnesite is fed to two Herreshoff furnaces. By controlling
the amount of CO2 liberated from the magnesite a caustic
oxide is produced from these furnaces. The magnesium oxide
200
-------
is cooled and ground in a ball mill into a variety of grades
and sizes, and is either bagged or shipped in bulk.
Magnesite is beneficiated at facility 2063 by either heavy
media separation (HMS) and/or froth flotation methods. In
the HMS facility, the feed is crushed to the proper size,
screened, washed and drained on a vibratory screen to
eliminate the fines as much as possible. The screened feed
is fed to the separating cone which contains a suspension of
finely ground ferro-silicon and/or magnetite in water,
maintained at a predetermined specific gravity. The light
fraction floats and is continuously removed by overflowing a
weir. The heavy particles sink and are continuously removed
by an airlift.
The float weir overflow and sink airlift discharge go to a
drainage screen where 90 percent of the medium carried with
the float and sink drains through the screen and is returned
to the separatory cone. The "float" product passes from the
drainage section of the screen to the washing section where
the fines are completely removed by water sprays. The solid
wastes from the wet screening operations contain -0.95 to
+3.8 cm (-3/8 to +1-1/2in) material which is primarily used
for the construction of settling pond contour. The fines
from the spray screen operations,, along with the "sink" from
the separating cone, are sent into the product thickener.
In the flotation facility, the feed is crushed, milled, and
classified and then sent into the cyclone clarifier. Make-
up water, along with the process recycled water, is
introduced into the cyclone classifier. The oversize from
the classifier is ground in a ball mill and recycled back to
the cyclone. The cyclone product is distributed to the
rougher flotation 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 bagged for
shipment.
The tailings from the flotation operation and the filtrate
constitute the waste streams of these facilities and are
sent into the tailings thickener for water recovery. The
overflows from either thickener are recycled back to
process. The underflow from the tailings thickener
containing about 40 percent solids is impounded in the
facility. A simplified flow diagram for this facility is
given in Figure 45.
This facility1s fresh water system is serviced by eight
wells. All wells except one are hot water wells, 50 to 70°c
(121° to 160°F). The total mill intake water is 2,200,000
201
-------
ro
o
ORE.
CRUSHERS
5% 15%
FINES TO
TO KILN
WASTE
RECYCLED
WVTER
1
-»
CRUSHER
HEAVY
MEDIA
SEPARATION
PLANT
<50% |
•* SOLID
WASTE
FLOTATION
AGENT
<30% 1
f i
-^
CRUSHERS
ROD MILLS
AND
CLASSIFIERS
ROUGHER
AND
CLEANER
CELLS
T 1 RECYCLE
i
OVERFLOW
TAILINGS
THICKENER
I
CONCENTRATE _ VACUUM
THICKENER """" FILTERS
FILTRATE
MAKE-UP WATER
UNDERFLOW
^___^^J U1XU&I
40% SOLIDS
TO SETTLING POND
VENT
MAGNESIA;
PRODUCT
FIGURE 45
MAGNESITE MINING AND PROCESSING
-------
I/day (580,000 gal/day), 88 percent of which is cooled prior
to usage. The hydraulic load of this facility is given
below:
water consumption
process water to refine the
product
road dust control
sanitary
tailing pond evaporation
tailing pond percolation
evaporation in water sprays.
I/day {gal/day)
163,000 (43,000)
227,000 (60,000)
11,360 ( 3,000)
492,000 (130,000)
757,000 (200,000)
Baker coolers 6 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).
203
-------
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.
204
-------
ro
o
01
SHALE
PIT
PIT
PUMPOUT
COARSE
1
PRIMARY
CRUSHER
(2RIMTI
uniroU
SCREEN
• PRODUCTS
RGURE 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 100%
recycled. Dust control requires about 1,890,000 I/day
(500,000 gpd) of water which is also recycled. Any make-up
water needed due to evaporation losses comes from the river.
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/kkg 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.
206
-------
LEGEND
DRY PROCESS
WET PROCESS
DRYING
AND
SCREENING
IRON SANDS
TO LANDFILL
OR'SEACH SAND
POND
APLITE
PRODUCT
APLITE
PRODUCT
FIGURE 47
APLITE MINING AND PROCESSING
EFFLUENT
-------
kq/kkq
Waste kkq/year product
Materials (ton/yr) (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.
208
-------
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE
There are 33 known facilities in the U.S. producing talc,
steatite, soapstone and pyrophyllite. Twenty-seven of these
facilities use dry grinding -operations, producing ground
products. Two utilize log washing and wet screening
operations producing either crude talc or ground talc. 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 48.
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 2034 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
209
-------
FIGURE 48
TALC ORE-
JAW wrr
AND WET
CCNE °* °"f * f
CRUSHERS DIN
r
-.FINE — J
CRUSHING -. J™.
HD tttYING "
-------
classifier is either shipped as is or it is further
processed in a dry grinding mill to various grades of
finished product.
At facility 2034 wash water is sent into a hydroclone system
for product recovery. The slimes from the hydroclone are
then discharged into a settling pond for evaporation and
drying. At facility 2035, the wash water, which carries the
fines, is sent directly into a settling pond.
The wet facilities in this subcategory are operational on a
six-month per year basis. During freezing weather, these
facilities are shut down. Stockpiles of the wet facility
products are accumulated in summer and used as source of
feed in the dry grinding facility in winter. Simplified
diagrams for facilities 2034 and 2035 are given in Figure
48.
Both facilities are supplied by water wells on their
property. Essentially all water used is process water.
Facility 2034 has a water intake of 182,000 I/day
(48,000 gal/day) and facility 2035 has a water intake of
363,000 I/day (96,000 gal/day).
The raw waste from facility 2034 consists of the slimes from
the hydroclone operation; that of facility 2035 is the
tailings emanating from the wet screening operation and the
slimes from the classifiers.
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
211
-------
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 49.
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 before 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 #1 drier for dust control. On drier
#2 (product drier) a baghouse is used and the dust recovered
is marketed. A simplified process flow diagram for this
facility is given in Figure 50. The hydraulic load of these
facilities is summarized as follows:
212
-------
FIGURE 49
TALC ORE"
LEGEND:
VWTER
1 1 '
* 1 '
CRUSHING 1 j CTCTR
GRiKL.JG 1 CCNCEN
1 . TAI
t L
l
LP 1
3UTOR l
NO r-**
TRATlrlG 1
*LES i
FLOTATION
REAGENTS
I
DISTRIBUTOR
ANO
FLOTATION
CELLS
1
1
l 1
THICKENER
FILTER
TAILINGS BASIN
!
1
^_
CLARIFICATION
BASINS
•PRODUCT
> ALTERNATE PROCESSES
7
INT
TALC MINING' AND PROCESSING
CRUDE ORE— »
CAUSTB""1 *
SCRUBBER,
BALL MILL,
THICKENER
T 20%
RECYCLE , i
LIME B»
WATER
AND
REAGENTS TAILINGS
1
a rnrjniTiOMFR JU> FLOTATION
1 1 '
SUMP
SULFUROU3
ACID
1
__, CONCENTRATING __. ^SS.J]
-*" TABLES ~* T^!
i
3SAT, DRYER,
:NER, — «• GRINDER,
IRS BAGGER
•PRODUCT
TO SETTCINS PONO
TALC MINING AND PROCESSING
(IMPURE ORE)
213
-------
ORE
AIR
WATER
PRIMARY
CRUSHER
-1
DRYER
J
WET
SCRUBBER
1
SETTLING
POND
1
CRUSHING
AND
SCREENING
'
1
PEBBLE
MILLS
AIR
CLASSIFIER
WATER
\
HEAVY
. MEDIA
PLANT
1
SCREENING
AND
SCREW
CLASSIFIERS
1
._„_ ^ PYROPHYtUTE
"~ PRODUCT
CRUSHING
SCREENING
WET SAND
BY-PRODUCt
__ ANDALUSITE
1 — ' BY-PRODUCT
' -^ PYROPHILLITE
, ** BY-PRODUCT
EFFLUENT
WASTE
TO SETTLING POND
FIGURE 50
PYROPHYLLITE MINING AND PROCESSING
(HEAVY MEDIA SEPARATION)
-------
Consumption I/day (gal/day)
at Facility No. 2031 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 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 kq/kkg of flotation product (lb/1000 Ib)
at Facility No. 2031 2032 2033 2044
TSS 1800 1200-1750 800 26
215
-------
NATURAL ABRASIVES
Garnet and tripbli 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 H
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 equipment. The ore is trucked to a
primary crushing facility and from there conveyed to the
mill where additional crushing and screening occurs. The
screening produces the coarse feed to the heavy-media
section and a fine feed for flotation. The heavy-media
section produces a coarse tailing which is dewatered and
stocked, a garnet concentrate, and a middling which is
reground and sent to flotation. The garnet concentrate is
then dewatered, filtered, and dried.
Facility 3037 mines shallow open pits, stripping off
overburden, then using a dragline to feed the garnet-bearing
earth to a trumble (heavy rotary screen). Large stones are
recovered and used for road building or to refill the pits.
The smaller stones are trucked to a jigging operation 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.
216
-------
WATER -
COARSE\
QUARRY
•*»
HEAVY
MEDiA
PLANT
A <• RECYCLE
JL.
DEWATERING
SCREEN
WATER-
RECYCLE .
TRUMBLE
LARGE
STONES
FOR
FILL
WATER-
JIG
I
1L
SETTLING
POND
I
EFFLUENT
FINESsJ*
WATER
COARSE TAILINGS
SOLD AS ROAD GRAVEL
DRYING
PRODUCT
EFFLUENT
FIGURE 51
GARNET MINING AND PROCESSING
-------
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 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 unique process using wet-milling
and scrubbing.
There is no water used in mining, nor is there any ground
water or rain water accumulation in the mines. The standard
process is a completely dry process. 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.
218
-------
BAG
HOUSES
I
CYCLONES
fs>
MINE
CRUSH
SCREEN
DRY
MILL
I
AIR
CLASSIFY
PRODUCT
FIGURE 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
diatomite is dug from the ground and loaded onto trucks.
Facilities 5504 and 5505 haul the crude diatomite directly
to the mills for processing. At facility 5500 the trucks
carry the crude diatomite to vertical storage shafts placed
in the formation at locations above a tunnel system. These
shafts have gates through which the crude diatomite is fed
to an electrical rail system for transportation to the
primary crushers.
At facility 5500, after primary crushing, blending, and
distribution, the material moves to different powder mill
units. For "natural" or uncalcined powders, crude diatomite
is crushed and then milled and dried simultaneously in a
current of heated air. The dried powder is sent through
separators to remove waste material and is further divided
into coarse and fine fractions. These powders are then
ready for packaging. For calcined powders, high temperature
rotary kilns are continuously employed. After classifying,
these powders are collected and packaged. To produce
flux-calcined powders, particles are sintered together into
microscopic clusters, then classified, collected and bagged.
At facilities 5504 and 5505, the ore is crushed, dried,
separated and classified, collected, and stored in bins for
shipping. Some of the diatomite is calcined at facility
5505 for a particular product. 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
220
-------
WAT£R
RECYCLE |
WATER — »
VENT
BAG HOUSE
T DUST
BINS
PRODUCT
ro
ro
MINE
CRUSH
DRY
AIR CLASSIFY
REAGENT
T
I
I
LEGEND:
GENERAL PROCESS FLOW
' } ALTERNATE PROCESS
[ ROUTES
CLASSIFY
^PRODUCT
—^PRODUCT
WASTE TO LAND DISPOSAL
RGURE 5^
DIATOMITE MINING AND PROCESSING
-------
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.
1/kkcr ore processed
(gallon/ton)
5500 5505 5504
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 cooling 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/kkq ore (lb/1000 Ib)
Facility 5500, oversize, 200
dust fines
Facility 5504, sand, rock, 175
heavy diatoms
Facility 5505, dust 45
fines (slurry)
222
-------
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 I/metric 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.
223
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GRAPHITE ORE
ro
ro
LIME
MAKE-UP
WATER REAGENTS WATER
j SEER4GE
I MINE i 2 .J
i PITS r ~*
i 1
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 quarry 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.
225
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WATER
SiC
QUARRY
-OIL
WATER
SIC
WATER
AND
POLISHING
AGENTS
RECYCLE
WIRE
SAW
DIAMOND
SAW
ro
ro
SETTLING
TANK
I I
1
SETTLING
TANK
i
• PRODUCT
RECYCLE POLISHING
AGENTS TO EXTENT
POSSIBLE
WATER
TO
GROUND
TAILINGS
TO
LANDFILL
TAILINGS
TO
LANDFILL
FIGURE 55
JADE MINING AND PROCESSING
-------
NOVACULITE
Novaculite, a generic name for large geologic formations of
pure, micr©crystalline 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 diagram 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.
227
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ro
ro
CO
VENT
DRY
MIX
SPECIALTY
PRODUCTS
QUARRY
1
CRUSHER
rjRYFR
uni cr\
'
1 *
• AIR
CLASSIFY
PRODUCT
PEBBLE
MILL
FIGURE 56
NOVACUL1TE MSNiNG 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.
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 4,000 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 4,000 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
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boilers and cause interference with cleanness, color, or
taste of 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 450 mg giving severe symptoms and 4.0 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 of children; these
studies lead to the generalization that water containing
less than 0.9 to 1.0 mg/1 of fluoride will seldom cause
mottled enamel in children, and for adults, concentrations
less than 3 or 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 2.4 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
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total ration of dairy cows are considered the upper safe
limit. Fluoride from waters apparently does not accumulate
in soft tissue to a significant degree and it is transferred
to a very small extent into the milk and to a somewhat
greater degree into eggs. Data for fresh water indicate
that fluorides, are toxic to fish at concentrations higher
than 1.5 mg/1.
Fluoride is found in 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 logarithm 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
aquatic 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.
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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 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.
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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
effectiveness of chlorination and can result in difficulties
in meeting BOD and suspended solids limitations. Turbidity
is an indirect measure of suspended solids.
SULFIDES
Sulfides may be present in significant amounts in the waste-
water 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
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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 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
U8 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
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through conventional treatment. Zinc can have an adverse
effect on man and animals at high concentrations. v 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 were studied but were not
found to be significant because of the following reasons:
(1) they are not usually present in quantities sufficient to
cause water quality degradation;
(2) treatment does not "practicably" reduce the parameter;
or
(3) 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 world5s production. The others, all
amphiboles, are ainosite, crocidolite, anthophyllite, and
tremolite. The asbestos minerals differ in their metallic
elemental content, range of fiber diameters, flexibility or
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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.
Chrysotile 3MgO2SiO2^2H£O
Anthophyllite (FeMg) •SiO-3«H2!O
Amosite (ferroanthophyllite)
Crocidolite NaFe*(S±O3) ^•FeSiOl»H2O
Tremolite Ca.2Mg.5Si{3O22 (OH) 2
All epidemiclogic studies that appear to indicate
differences in pathogenicity among types of asbestos are
flawed by their lack of quantitative data on cumulative
exposures, fiber characteristics, and the presence of
cofactors. The different types, therefore, 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.
However, methods which are technically and economically
practicable for most operations for removing asbestos from
effluents are not available.
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 responsd to radiation exposure.
236
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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.
Aquatic 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 fresh or maring products that may
accumulate radioactive materials are used as food by humans,
the concentrations of the radionuclides 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 radionuclide 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
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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
consequences, 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. Although available treatment is specific for
suspended solids and not radium,removal of TSS results in
removal of the latter. Therefore, limitations based on
treatment for TSS rather than specifically for radium 226
are felt to be appropriate at this time.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
Waste water pollutants from the mining of minerals for the
construction 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,
(4) 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 dif-
ferent categories:
(1) Mine dewaterinq. 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 major 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
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storage piles is a potential source of pollutant loading to
nearby surface waters. Several current industry practices
to control this pollution are:
(1) Construction of ditches surrounding Storage areas
to divert surface runoff and collect seepage that
does occur.
(2) Establishment of a vegetative cover of grasses in
areas of potential sheet wash and erosion to
stabilize the material, to control erosion and
sedimentation, and to improve the aesthetic aspects
of the area.
(3) Installation of hard surfaces on haul roads,
beneath conveyors, etc., with proper slopes to
direct drainage to a sump. Collected waters may be
pumped to an existing treatment facility for
treatment.
Another potential problem associated with construction of
tailing-pond treatment systems is the use of existing
valleys and natural drainage areas for impoundment of mine
water or process waste water. The capacity of these
impoundment systems frequently 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.
241
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Utilization of the box-cut technique in moderate- and
shallow-slope contour mining has increased recently because
more stringent environmental controls are being implemented.
A box cut is simply a contour strip mine in which a low-wall
barrier is maintained. Spoil may be piled on the low wall
side. This technique significantly reduces the amount of
water discharged from a pit area, since that water is
prevented from seeping through spoil banks. The problems of
preventing slides, spoil erosion, and resulting stream
sedimentation are still present, however.
Block-cut mining was - developed to facilitate regrading,
minimize overburden handling, and contain spoil within
mining areas. In block-cut mining, contour stripping is
typically accomplished by throwing spoil from the bench onto
downslope areas. This downslope material can slump or
rapidly erode and must be moved upslope to the mine site if
contour regrading is desired. The land area affected by
contour strip mining is substantially larger than the area
from which the ores are extracted. When using block-cut
mining, only material from the first cut is deposited in
adjacent low areas. Remaining spoil is then placed in mined
portions of the bench. Spoil handling is restricted to the
actual pit area for all areas but the first cut, which
significantly reduces the area disturbed.
Pollution-control technology in underground mining is
largely restricted to at-source methods of reducing water
influx into mine workings. Infiltration from strata
surrounding the workings is the primary source of water, and
this water reacts with air and sulfide minerals within the
mines to create acid pH conditions and, thus, to increase
the potential for solubilization of metals. Underground
mines are, therefore, faced with problems of water handling
and mine-drainage treatment. Open-pit mines, on the other
hand, receive both direct rainfall and runoff contributions,
as well as infiltrated water from intercepted strata.
Infiltration in underground mines generally results from
rainfall recharge of a ground-water reservoir. Rock
fracture zones, joints, and faults have a strong influence
on ground-water flow patterns since they can collect and
convey large volumes of water. These zones and faults can
intersect any portion of an underground mine and permit easy
access of ground water. In some mines, infiltration can
result in huge volumes of water that must be handled and
treated. Pumping can be a major part of the mining
operation in terms of equipment and expense—particularly,
in mines which do not discharge by gravity.
242
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Water-infiltration control techniques, designed to reduce
the amount of water entering the workings, are extremely
important in underground mines located in or adjacent to
water-bearing strata. These techniques are often employed
in such mines to decrease the volume of water requiring
handling and treatment, to make the mine workable, and to
control energy costs associated with dewatering. The
techniques include pressure grouting of fissures which are
entry points for water into the mine. New polymer-based
grouting materials have been developed which should improve
the effectiveness of such grouting procedures. In severe
cases, pilot holes can be drilled ahead of actual mining
areas to determine if excessive water is likely to be
encountered. When water is encountered, a small pilot hole
can be easily filled by pressure grouting, and mining
activity may be directed toward non-water-contributing areas
in the formation. The feasibility of such control is a
function of the structure of the ore body, the type of
surrounding rock, and the characteristics of ground water in
the area.
Decreased water volume, however, does not necessarily mean
that waste water pollutant loading will also decrease. In
underground mines oxygen, in the presence of humidity,
interacts with minerals on the mine walls and floor to
permit pollutant formation e.g., acid mine water, while
water flowing through the mine transports pollutants to the
outside. If the volume of this water is decreased but the
volume of pollutants remains unchanged, the resultant
smaller discharge will contain increased pollutant
concentrations, but approximately the same pollutant load.
Rapid pumpout of the mine can, however, reduce the contact
time and significantly reduce the formation of pollutants.
Reduction of mine discharge volume can reduce water handling
costs. In cases of acid mine drainage, for example, the
same amounts of neutralizing agents will be required because
pollutant loads will remain unchanged. The volume of mine
water to be treated, however, will be reduced significantly,
together with the size of the necessary treatment and
settling facilities. This cost reduction, along with cost
savings which can be attributed to decreased pumping volumes
(hence, smaller pumps, lower energy requirements, and
smaller treatment facilities), makes use of water
infiltration-control techniques highly desirable.
Water entering underground mines may pass vertically through
the mine roof from rock 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 over-
243
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lying 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; (4) Backfilling
of the mined areas with waste material.
Surface mines are often responsible for collecting and
conveying large quantities of surface water to adjacent or
underlying underground mines. Ungraded surface mines often
collect water in open pits when no surface discharge point
is available. That water may subsequently enter the ground-
water system and then percolate into an underground mine.
The influx of water to underground mines from either active
or abandoned surface mines can be significantly reduced
through implementation Of a well-designed reclamation plan.
The only actual underground mining technique developed
specifically for pollution control is preplanned flooding.
This technique is primarily one of mine design, in which a
mine is planned from its inception for post-operation
flooding or zero discharge. In drift mines and shallow
slope or shaft mines, this is generally achieved by working
the mine with the dip of the rock (inclination of the rock
to the horizontal) and pumping out the water which collects
in the shafts. Upon completion of mining activities, the
mine is allowed to flood naturally, eliminating the
possibility of acid formation caused by the contact between
sulfide minerals and oxygen. Discharges, if any, from a
flooded mine should contain a much lower pollutant
concentration. A flooded mine may also be sealed.
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 includingi
O) Solids removal. Solids settle to the bottom and the
clear water overflow is much reduced in suspended solids
content.
(2) Equalization 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.
245
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Settling ponds used in the minerals industry range from
small pits, natural depressions and swamp areas to
engineered thousand acre structures with massive retaining
dams and legislated construction design. The performance of
these ponds 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-<*50 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.
In this industry, settling is usually a prelude to recycle
of water for washing 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 154 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
246
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Plant
Table 12
Settling Pond Performance
Stone, Sand and Gravel Operations
TSS
(mg/l) Percent
Influent Effluent Reduction
Dimension Stone
3001 1,808
3003 3,406
3007 2,178
Crushed Stone
1001 1,054
1003 7,680
1004 5,710
1021 7,206
(2 ponds) 772
1039 10,013
1053 21,760
Construction
Sand and Gravel
1017 (D) 5,712
1044 5,114
1083 (A) 20,660
1083 (B) 8,863
1129 4,660
1247 (D) 93
1391 12,700
Industrial Sand
1019 2,014
1101 427
1102 2,160
D - Dredge
A - Main Plant
B - Auxiliary Plant
37
34
80
8
8
12
28
3
14
56
51
154
47
32
44
29
18
56
56
66
97.95
99
96.3
99.24
99.92
99.79
99.61
99.61
99.86
99.74
99.12
96.99
99.77
99.64
99.06
68.82
99.86
97.22
86.88
96.94
Treatment,
Chemical
none
FeC13_, sodium
bicarbonate
none
none
none
none
none
none
none
none
flocculating
none
none
none
none
flocculating
agent
none
none
none
flocculating
247
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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.
FLOCCULATION
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. Agglomeration, or flocculation, can then be
achieved with less reagent and less settling load on the
polishing pond or clarifier.
Flocculation agents can be used with minor modifications and
additions to existing treatment systems, but the costs for
the flocculating chemicals are often significant. Ionic
types are used in 10 to 100 mg/1 concentrations in the waste
water while the higher priced polymeric types are effective
in the 2 to 20 mg/1 concentrations. Flocculants have been
used by several segments within the minerals industry with
varying degrees of success.
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
248
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directing and segregating mechanisms to provide efficient
concentration and removal of suspended solids in one
effluent stream and clarified liquid in the other.
Clarifiers differ from thickeners primarily in their basic
purpose. Clarifiers are used 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 required, 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 require 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.
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
249
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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 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
250
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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.
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[
251
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(2) Mn+2 + 20H- = Mn(OH)_2
(3) Zn+2 + 2OH- = Zn(OH),2
(U) Pb+2 + 2 (OH)~ = Pb(OH)2
(5) Cu+2 + 20H- = CU(OH)2-
Oxidation-Reduction Reactions
The modification or destruction of many hazardous wastes is
accomplished by chemical oxidation or reduction reactions.
Hexavalent chromium is reduced to the less hazardous triva-
lent form with sulfur dioxide or bisulfites. Sulfides, with
large COD values, can be oxidized with air to relatively
innocuous sulfates. These examples and many others are
basic to the modification of inorganic chemical wastes to
make them less troublesome. In general waste materials
requiring oxidation-reduction treatments are not encountered
in these industries.
Precipitations
The reaction of two soluble chemicals to produce insoluble
or precipitated products is the basis for removing many
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:
252
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(1) SO£= + Ca(OH).2 = CaSO4 * 20B-
(2) 2F- + Ca (OH) £ = CaF2 * 2OH~
(3) Zn++ + Na2CO3 = ZnCO_3 '* 2Na*
EXAMPLES OP 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 occasionally 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
100% recycle
none
settling
settling
settling
settling
settling, 100% recycle
settling
settling, 100% recycle
settling
settling
flocculants, settling,
100% 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.
253
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non-granite processors could not obtain any cost benefits
from this SiC recovery practice.
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, 3010), 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
follows:
Facility 3007
Facility 3304
Facility 3305
Facility 3306
Facility 3002
Facility 3003
Facility 3001
Facility 5600
of treated effluents available are as
7.8 pH
7.1 mg/1 TSS (range 0-24.5)
<10 JTU
<100 mg/1 total solids
<5 mg/1 TSS
<1 BOD
<1 JTD
600 mg/1 TSS
34 mg/1 TSS
Water including runoff from 2
quarries
1 mg/1 TSS
4 mg/1 TSS
Finishing Facility-37 mg/1 TSS
Quarry - 7 mg/1 TSS
254
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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 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) e .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 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
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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
1218 Flow - 6.2 x 10*
I/day (1.64 mgd)
TSS - 20 mg/1
source
treated discharge composed
of wash water (4X) and
pit pumpout (96%)
wash water after treatment
wash water after treat-
ment then combined with
pit pumpout
Of the facilities contacted the 'following are practicing
total or partial recycle of process generated waste water:
1001
1002
1003
1023
1039
1040
1062
1063
1064
1161
1212
1217
1220
1222
1227
1228
1250
1439
3027
5662
5612
5663
5664
The types of treatment used and the TSS values for raw and
treated waste are shown below for a number of facilities.
Facility
1001*
1003
1004
1021
1023*
1039
TSS
Treatment System
Settling pond
Raw Waste
1,054z
Treated Effluent
82
Settling pond (with
total recycle) 7,687*
Settling pond
Settling ponds
5,7102
7,064, 1422
7722
Settling pond (with
partial recycle)
Flocculation,de-
watering screw and
122
282
32
34»
256
-------
settling pond (with
total recycle) 10,0132 72
1053 Settling pond
21,7602 562
1218 Settling pond (with
total recycle) 20»
1219* Settling pond (with
partial recycle) 2l
1439 Settling ponds
(with total
recycle) 7,000-8,000* 15-20*
5662* Settling pond
(with partial
recycle) 9»
5664* Settling pond
(with partial
recycle) 40, 42*
1 Company supplied data
2 Contractor verification data
* These facilities use a common pond for treating process waste
water and mine water.
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 subcategory 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 quantity 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.
257
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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 quarry 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 mq/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)
2
10-
1,
17,
5,
32,
1,
15,
14
0
1
42.
5, (2)1
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 MONITORING DATA
NPDES Discharge Monitoring Reports (DMRS) were obtained for
more than 65 plants in the crushed stone subcategory.
Treatment technologies used at these facilities is unknown.
The total number of DMRS was 755, however, only 631 reports
258
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had comparable sampling frequencies: one sample in thirty
days. The average TSS values for these 631 facilities (some
plants have more than one discharge) are given below:
avg. mean/avg. max.
» of DMRS sample type TSS mq/1
575 quarry dewatering 13.1/24.5
115 commingled 28.0/45.3
9 process water 8.8/29.0
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 from the ponds. This loss is
made up by the addition of fresh water.
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.
259
-------
Intake intake
water effluent water effluent
(3069) (3069) (1021) (1021)
TSS 5 10 34
(mg/1)
BOD 1.0 <1.0
(mg/1)
COD 1.0 <1.0 0 4
(mg/1)
sulfate 3.5 <2.0 13 19
(mg/1)
turbi- 10 6 42
dity (FTU)
chloride 3.8 4.1 50 20
(mg/1)
total 32 128 464 154
solids
(mg/1)
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 (150)
TSS, mg/1 55
TSS, kg/kkg of product (1 lb/1000 Ib) 0.034
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:
260
-------
Input
Facility TSS (mq/1)
1055
1235
1391
1555
3049
5617
5631
5674
unknown
unknown
4,550
15,000
5,000
unknown
unknown
unknown
Output
TSS (mg/11
25
Treatment
spiral classi-
fiers , 4-hectare
(10-acre) settling
basin
mechanical thick-
eners, settling
ponds
mechanical thick- 32
eners, cyclones,
2-hectare (5-acre)
settling basin
cyclones, 14-hectare 35
(35-acre) settling
basin
cyclones, vacuum 30
disc filter, 2-hectare
(5-acre) settling pond
with polymer floe
dewatering screws, unknown
settling ponds
dewatering screws, unknown
10-hectare (25-acre)
settling pond
dewatering screws, unknown
0.8-hectare (2-acre)
settling pond
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. So'me 'have available land for
impoundment construction. The following lists the suspended
261
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solids concentration of treated waste water effluents from
facilities discharging:
Facility Treatment TSS, mg/1
1006 dewatering screw, 55
settling ponds
1044 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
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 percolation:
1231 1232 5666 5681
262
-------
The following facilities previously mentioned as recycling
all process generated waste waters declared that significant
perculation occurs in their ponds:
1057 T058 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/kkq of product kq/kkq of product
Facility (gal/ton) (lb/1000 Ibj
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 (DREDGING-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 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:
263
-------
Haw Waste Load,
Facility TSS (mcy/l)
Treated Recycle
Water,
TSS (mcf/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:
Facility
1010
1009
TSS, kg/kkq of product
(lb/1000 Ib)
22
0.10
264
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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 ^s 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 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.
265
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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 to 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
(mcr/1) Intake Effluent Intake Effluent
pH 7.8 5.0 7.6 7.0-7.8
TDS 209 192
TSS 54 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
INDUSTRIAL SAND (ACID LEACHING)
Process water at facility 3215,is treated by neutralization
with slaked limestone and lagooning to settle " part of the
iron. The existing system of settling ponds is an extensive
one; this treatment system contains approximately ten acres
of ponds.
The effluent from the treatment system is combined with the
effluent from the companyfs construction sand plant. The
combined effluents are discharged to surface waters. The
composition of the combined effluent is given below:
kg/kkg (Ib/ton) of product
pH (units)
max. 7.2
min. 6.4
TSS
average 1.01 (2.02)
Iron
266
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average
0.065 (0,13)
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 quarry water are given as follows:
facility
1041
1042
1110
1112
1997
1999
flow, 10*
I/day Cmgd)
4.4 (1.17)
6=4 (1.70)
.19 (0.05)
5.1 (1.35)
0.68 (0.18)
6.5 (1.71)
TSS,
mq/1
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
flow,l/kkg of
product (gal/ton)
none
246 (59)
none
250 (60)
4.5 (1)
TSS
mq/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 circuit,
resulting in no discharge of process waste water. In the
recycle circuit, the HMS media (magnetite/ferrous silica) is
reclaimed and is reused in the separation process.
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 quarry. Waste fines at facility
1100 settle out in the primary settling basin and must be
periodically dredged. This waste is hauled to the quarry
and deposited.
BITUMINOUS LIMESTONE
267
-------
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 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/l>
intake effluent mine pumpout
Suspended solids 33 17 3375
BOD 35 43 12
pH 7.7 8.2 7.9 - 8.1
TDS 401 2949 620
Turbidity -- ~ 70 JTU
Arsenic — — 0.01
Barium — — <0.01
Cadmium — <0.001 0.004
Chloride — 0.15 8.8
Sulfate ~ 363 195
ASBESTOS
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) 545,000-3,270,000 (0.144-0.864)
TSS, mg/1 2.0
Fe, mg/1 0.15
pH 8.4-8.7
asbestos (fibers/liter) 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
268
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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 pondsa Data on the
waste stream to the percolation pond includes the following:
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 1'04
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 along-
side the pond, allowed to dry, and landfilled.
269
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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 D.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.
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
270
-------
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 has suspended its operation
since June, 1974, due to necessary repairs to the pond, and
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, 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:
271
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facility
2052
2054
2057
pH before lime
treatment
.2
6-9
400
4.3
6.5
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
Intermittent* Mill tailings,
runoff
Intermittent* Well water
from clear
water pond
None from Mill tailings
tailings pond
2013 None
2015 Intermittent*
2016 Intermittent*
2017 Intermittent*
2018 Intermittent*
Mill tailings
Mill tailings,
runoff
Mill tailings,
runoff
Mill tailings,
runoff
Mill tailings,
runoff
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
Flocculation,
recycle
Pond, recycle
Pond, recycle
Pond 24 ha
(60 ac)
272
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2020 Intermittent* Well water
from clear
water pond
None from Mill tailings Pond, 2 ha
settling pond (6 ac)
2046 Intermittent* Well water Pond, 12 ha
from clear (30 ac)
pond clarification
None from Mill tailings Pond, recycle
tailings pond
2112 None Slime Pond 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 2011
Daily Aver. - Max.
pH 6.0 - 8.0
TSS, mg/1 15 32
Total barium,
mg/1 0.1 - 0.5
Iron, mg/1 0.04 - 0.09
Lead, mg/1 0.03 - 0.10
BARITE (FLOTATION)
Wastewater is treated by clarification and either recycled
or discharged. A summary of the treatment systems is given
as follows:
273
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Facility Discharge
Source
Treatment
2010 Intermittent »
Intermittent
201« None
None
2019 Intermittent 2
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
* 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 1.8 (3.5)
800-1271 467 (934)
<0.1-0.1 <0.5 1
0.004-0.008 <0.5 1
0.200-0.400 <0.5 1
0.030-0.060 <0.5 (1)
0.020-0.080 <0.5 (1)
0.002-0.008 <0.5 (1)
0.030-0.070 <0.5 (1)
0.005-0.010 <0.5 (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
274
-------
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
HO 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)9 the effluent
discharge from this facility would be 946,000 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.
BARITE (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;
275
-------
Parameter
New
Facility Pond
Data Design
Verification
Sampling
pH
Acidity
Hardness
TDS
TSS
S04.
Fe, total
Fe, 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
404
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 company1 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 (4.5 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 mg/1
Fluoride
TSS
Lead
Zinc
pH
3.0
10.0
0.015
0.09
7.8
kg/kkg of product
{lb/1000 Ib)
0.04
0.13
0.0002
0.0012
276
-------
FLUORSPAR (FLOTATION)
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, 1.6r and 2.4 hectares (7, 4, 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
4 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 be
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.
277
-------
Effluents reported by facilities 2000 and 2001 for their
current operation and anticipated performance are:
concentration (mq/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/kk
-------
TABLE 13
FLUORSPAR MINE DEWATERING DATA
2085 2092
settling settling
mg/1 2080 2081 2082 2083 mine pond 2086 2088 2089 2090 2091 mine pond 2093
pH 8.1 7.1 7.6 7.6 7.4 7.7 8.1 7.7 7.2 7.9 *8.0
Alkalinity 224 276 216 245 864 210 197
Hardness 336 1600 1600 221 235 222
Cl 35 185 162 48 23 17
TSS 38 10 8 2-12 15 29 12 20 122-135 4-69 10 53 20 17
TDS 469 697 400 478 3417 1753 1078 583 536 379 364
S04_ 35 107 480 575 61 56 38 32
F 1.4 2.4 1.4 1.3 2.75 1.7 2.3 1.4 2.3 3.2 1.6
Fe 1.0 0.05 0.66 0.26 .05 2.0 0.05 .05 1.33 0.50 0.9
Pb .03 0.1 .02 < 0.2 <0.2 < 0.2 .03 .03 < 0.2 < 0.2 0.9 < 0.2 < 0.2 0.075
Mi 0.16 0.05 0.05 0.62 0.11 0.01 0.18 0.18 0.1
Zn 0.7 0.03 .08 0.76 <0.01 0.34 0.54 0.06 0.5 0.2 0.17 0.08 0.235
-------
SALINES (BRINE LAKES)
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:
280
-------
mq/1
kg/day (Ib/day)
total solids
dissolved solids
suspended solids
9,000
8,300
700
860
793
67
(1,900)
(1,750)
(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:
Volume
Facility I/day qal/day
4013
4026
4027
4033
4034
(C
4,090,000
150,000
500,000
76,000
(001) 306,000
)02b) 522,000
1,080,000
40,000
132,000
20,200
81,000
138,000
TDS
mg/1
4,660
30,900
. —
30,200
53,000 -
112,000
319,000 -
TSS
mq/1
trace*
72
150
trace**
470 -
1,870
PH
7.5
6.5
- —
8.5-9.0
7.6
323,000 4,750
* due to dilution
** runoff only, remainder of waste re-injected to well.
281
-------
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.
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 4015 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 4018 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 quite 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 4003
discharges some of the mine pumpout.
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,
(4) 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.
282
-------
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.
The following data summarize the results of the statistical
analyses:
PHOSPHATE EFFLUENT QUALITY
TSS, mg/1
Long
Term
Average
Monthly 99
percentile
Observed
Maximum
Monthly
Average
* **
Daily 99
Percen-
tile
*#
Observed
Daily
Maximum
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
*1974-1975 Data
**1975-1976 Data
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
4002
4004A(1)
4004A(2)
4004B(1)
4004B(2)
4004B(3)
4005A(1)
4005A(2)
4005B(1)
4005B(2)
4005C(1)
4005C(2)
4005C(3)
4015(1)
4015(2)
4015(3)
4016
4018
4019A
4019B
4019C
4020A
4020B
9.
9.
11.
13.
3.
2.
18.
'—
18.
16.
13.
15.
28.
15.
46.
14.
7.
158
7*
5.
6.
2.
5.
2
7
3
5
5
5
1
7
0
2
0
2
8
5
9
4
0
6
3
8
5
—
80
8
8
3
2
21
19
13
16
17
19
14
18
34
7
9
26
-
5
4
3
7
.8
r- 2
.3
. 1
.3
.7
.1
.9
.0
.1
.6
.3
.0
.9
.2
.4
.2
.9
.7
.5
26
14
-
53
6
5
29
—
25
22
23
-
-
18
109
- —
13
453
13
18
17
5
6
-
27
16
8
5
4
33
26
27
27
29
26
23
24
91
18
16
137
—
9
9
37
14
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
-
50.4
39.8
12.8
10.7
7.9
51.3
48.4
71.5
41.6
43.0
46.1
74.4
52.4
221
32.8
47.9
-
-
18.6
20.7
68.0
21.3
64
50
30
103
12
10
75
—
67
35
47
55
105
36
181
20
17
1072
41
-
43
14
12
-
44
32
12.0
7
7
49
47
62
41
47
37
70
55
182
24
46
1961
-
15
15
143
28
283
-------
FIGURE 57
Normal Distribution of Log Tss
for a Phosphate Slime Pond Discharge
PERCENTAGE
40 50 60
98%
284
-------
performed on less than 12 data points.
for some monthly data.
This was the case
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.
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-
solved
a/liter
Effluent Discharge
discharge dissolved undis-
point solved
4005
4015
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 appears to be directly
related to the concentration of TSS.
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.
285
-------
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 recycling back to the system. At facility
2020 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
286
-------
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.
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 equilibrated 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.
Pour discharge streams emanate from facility 2024.
Discharges #1 and *3, the power facility discharges and
mining water from sealing wells, respectively, discharge
into a river without treatment. Discharge *2r the
bleedwater, flows by gravity through a ditch into a
50 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.
287
-------
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 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
14 hectares (35 acres) and ponds #2 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
288
-------
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 wateis 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 24 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 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.
289
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iO
CJ
TABLE 14
St&FUR AGILITIES
COMPARISON OF DISCHARGES
Plant
Age
Location
Total Discharge, 10°
I/day 2
Total Discharge 10
Vkkg
Bleedwater discharge,
106 I/day
Bleedwater discharge,
10? Vkkg
Pollutants (in total
discharge)
TSS, rng/i
TSS, kg/kkg
Sulfide, mg/ 1
Suifide, kg/kkg
TSS (seawater contribution
omitted) kg/kkg 4.8 0.3 0.7 0.4 0.4 0.1 0.9 0.6 0.7
* Bayou
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
41.8
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
-------
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.
(II • Sulfides
Sulfides are readily oxidizable with air to thiosulfate.
Thiosulfates are less harmful than sulfides (of the order of
1000 to 1).
2HS- + 202 = S2Q3 - * 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.
(3) Hvdrosulfites
Hydrosulfites can also be oxidized by such oxidizing agents
and perhaps with catalyzed air oxidation.
(4) 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 bleed-
water 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
291
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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.
292
-------
FIGURE 58
SULFUROUS FLUE GAS
ACID TO STACK
i DEPOSITION A
INHIBITOR ]
, I r.
B.EEDWATER" =" BASIN wixfR PIPE
RAW WATER — »•
BOILER
GAS
PACKED
TC'.VERS
t
FLUE GAS
TO STACK
!
PACKED
TOWERS
i
k
ECONOMIZER
_. AERATORS ' to SETTLING
^ *4trt«tuKa "• BASINS
WASTE VOTER
DISCHARGE
TO PROCESS
FOR MINE WATER
BLEEDWER "TREATING PLANT
TYPE I
BUE6DWCTER-C=
WASTE 'TOTER
DISCHARGE
BLEEDWATER TREATING PLANT
TYPE 2
293
-------
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 s
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
294
-------
seepage from the tailings dam and
tailings pond during heavy rainfall.
as overflow from the
The mine water at mine 1001 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. Oust 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
3308
3309
3310
3332
3333
3334
Treatment
Pond
Lime & Pond
lime, combined
with other
waste streams
None
None
None
None
None
Pond
Pond
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
—
—
- —
TSS
mg/1
3
26.4,62
45
4
2
30
1
5
16
16
30
10
45
Total
Fe
mg/1
20
80
—
—
—
295
-------
3335 None r- 27,144
3336 None — 37
3337 None — 15
3338 None 2.6-3.0 253-392 530-1900
ATTAPULGITE
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 pJH TSS, mg/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)2), which
precipitates as calcium sulfate in the settling pond. To
296
-------
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.
Data on mine dewatering follows.
Mine pH TSSgmq/l
3059 4.5-5.5 200-400
3323 3.8-4.4 2 4.33 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.
297
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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 99.8% 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.
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 NTD
long term daily monthly
average maximum average
maximum
3024 26.4 48.2 <43
3025 24.5 83 62.5
3314 5.8.2 202
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 JTD(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 EPA at facility 3315.
Approximately one-half of the total suspended solids were of
a volatile nature confirming the company1s concern that
298
-------
aquatic growth in part was contributing to the suspended
solids. This is expected, since organic reagents are used
in kaolin 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 DEWATERING)
Open pit mining of kaolin does not utilize any water.
However* when rainwater and ground water accumulate in the
pits it must be pumped out and discharged. Usually this
pumpout is discharged without treatment, but, in at least
one case, pH adjustment is necessary prior to discharge.
The 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:
299
-------
TSS,
0
48
0
0
53
15
146
mg/1
23143
312
200
Mine
3326
3327
3328
3329
3330
3331
5684
The extreme variability of the effluent quality 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. In addition, facilities 5684 and 5689 treat the
scrubber water with a flocculating agent which improves
settling of suspended solids in the pond. Facility 5689 has
three ponds of a total of 1.0 hectare (2.5 acres) area.
The amounts of process wastes discharged by these facilities
are calculated to be:
discharge,
1/kkg of product
facility (gal/ton)
5684
5685
88 (21)
1,080 (260)
TSS, kcr/kkg
of product
(lb/1000 Ibl
0.0004
0.43
5689
834 (1,030)
0.17
TSS
mg/1
400
2970
82
1016
1054
10046
49
107
4
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.
300
-------
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
The process water effluents after treatment at these five
facilities have the following quality characteristics:
facility
3026
3054
3065
3067
3068
J2S
6.5-6.8
6.8
10.8*
7.5-8.0
7-8
TSS
mq/1
21
45
349
35
40-150
Fluoride
mg/1
8, i.3
15
23
34
32.
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.
301
-------
ore processed basis
flow, TSS, £lubridef
1/kkq kq/kkq kq/kkqr
facility (gal/ton) (lb/1000 Ib) (lb/1000 lb|
3026 14,600 0.31 0.12
(3f500)
3054 12,500 0.56 0.18
(3,000)
3065 11,000 1.1 0.25
(2,640)
3067 6,500 0.23 0.22
(1,560)
3068 18,600 0.7-2*8 0.6
(4,460)
The higher than average suspended solids content of the
effluents from 3065 and 3068 is caused by a froth carrying
mica through the thickerners to the discharges. 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.
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
c one entration.
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.
302
-------
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 (54 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. The
tailings pond is located at the upper end of an alluvial
fan. This material is both coarse and angular and has a
rapid percolation 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 pit's or streams.
APLITE
30*
-------
Facility 3020 discharges effluent arising from wet scrubber
operations to a creek after allowing settling of suspended
solids in a series of ponds. Aplite clays represent a
settling problem in that a portion of the clays settles out
rapidly but another portion stays in suspension for a long
time, imparting a milky appearance to the effluent. The
occasional mine pumpout due to rainfall is discharged
without treatment.
Facility 3016 recycles water from the settling ponds to the
process with only infrequent discharge to a nearby river
when pond levels become excessive (every 2 to 3 years).
This discharge is state regulated only on suspended solids
at 649 mg/1 average, and 1000 mg/1 for any one day. Actual
settling pond 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 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:
304
-------
7.5-8.3 4, 9
2037
2038
2039
2040
2041
2042
2043
7.8
8.1
7.0-7.8 1, 3
7.2-8.5 15
8.7
7.8
7.6
I/day
(gal/day)
545,000
£144,000)
878,000
(232,000)
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)
TALC (FLOTATION AND HMS)
28
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
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.
In facility 2033 the filtrate with a pH of 3.5-4.0, the
flotation tailings with a pH of 10-10.5 and the primary
thickener overflow are combined, and the resulting stream,
having a pH of 4.5-5.5, is sent to a small sump in the
facility for treating. The effluent pH is adjusted by lime
addition to a 6.5-7.5 level prior to discharge into the
settling pond. The lime is added by metered pumping and the
305
-------
pH is controlled manually. The effluent from the treating
sump is routed to one end of a ".O" shaped primary settling
pond and is discharged into a secondary or back-up pond.
The total active pond area is about 0.8 hectare (2 acres).
The clarification pond occupies about 0.3 hectare
(0.75 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 2044
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 Ib)
product
2032 <0.34
2033 0.29
2044 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 is sent to a series of
306
-------
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. The pH is maintained at 7. The suspended
solids content averaged 25 mg/i.
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.
307
-------
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:
Flow I/day
(gal/day)
total solids
TSS
Volatile
Solids
Mn
Total Fe
BOD
COD
pH
facility
average
mq/1
750
10
1
0.1
0.1
9
20
7.3-8.5
2H 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.
308
-------
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 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.
309
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-------
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.
311
-------
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, 55/100, n = useful life in years
The capital recovery factor equation above may be
rewritten as:
Uniform Annual Disbursement = P(CR - iJS - n)
Where (CR - ±% - n) is the Capital Recovery Factor for
iJS 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.
312
-------
(V) Off-site treatment/disposal land requirements and costs
are not considered directly. It is assumed that land
costs are included in the overall contractor's fees
along with its other expenses and profit.
(5) In view of the extreme variability of land costs,
adjustments have been made for individual industry
situations. In general, isolated, plentiful land has
been costed at $2,470/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
equalled or exceeded by most or all of the involved
facilities. Usually money for this treatment level has
already been spent (in the case of capital investment) or is
being spent (in the case of operating and overall costs).
B,CrD,E Levels - Successively greater degrees of treatment
with respect to critical pollutant parameters. Two or more
alternative treatments are developed when applicable.
313
-------
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.
(4) Mine dewatering treatments and costs are generally
considered separately from process water treatment and
costs. Mine dewatering 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.
314
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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 equipment.
Production:
18,000 kkg/yr (20,000 tons/yr)
8 hr/day; 250 days/yr
Water Use and Waste characteristics:
Treatment:
4,170 1/kkg (1,000 gal/ton) of product
2% of product in effluent stream
5,000 mg/1 TSS 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.)
Recycle of wash water after passing through
a one acre settling pond
Cost Rational:
Pond cost
Total pipe cost
Total pump cost
Power costs
Maintenance
Taxes and insurance
Capital recovery factor 0.1627
$10,000/acre
$1/inch diam/linear ft.
$100/HP
$0.02/kwh
5% of capital
2% of capital
315
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TABLE 15
DIMENSION STONE TREATMENT COSTS
PLANT SIZE
18,000
PLANT AGE 50 YEARS
KKG
PER YEAR OF Product
PLANT LOCATION "e°r 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.
316
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CRUSHED STONE
WET PROCESS
A typical wet crushed stone operation is assumed to produce
180,000 kkg/yr (200,000 tons/yr). The assumed wash water
usage is 1,000 1/kkg (240 gal/ton), and the assumed waste
content is 65» 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 400
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 400
Level D
Additional capital flocculant equipment $ 3,500
Additional annual capital 600
Annual chemical cost 1,000
Granite fines (non-carbonate) settle somewhat slower than
limestone fines (carbonate). 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
317
-------
TABLE 16
CRUSHED STONE (WET PROCESS) TREATIOT COSTS
PLANT SIZE 180,000
PLANT AGE 40 YEARS
KKG
PER YEAR OF Crushed Stone
PLANT LOCATION rural locationnear population center
INVESTED CAPITAL COSTS! •$
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 ft M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG product
WASTE LOAD PARAMETERS
(ka/ kfcg of product )
Suspended Solids
RAW
WASTE
LOAD
60
LEVEL
A
(MIN)
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.
318
-------
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.
MINE DEWATERING
Two typical pumpout rates are assumed for mine dewatering of
crushed stone plants. The cost data are presented in Tables
16A and 16B.
Level A involves enlarging a 1 acre-ft. quarry floor sump to
accomodate a 1 acre-ft, 2-stage sump separated by a
gravel/rock barrier (filter). The quarry is dewatered by
pumping from the second stage with existing pumps and lines
to the surface. Sump berms and filter are constructed from
on-site materials, using earth-moving equipment, etc.,
available from the mining operations. A small amount of new
pipe is needed to relocate the sump pump in the new second
stage sump. Annual cleanout will be required on the new
second stage sump, as well as the old first stage.
Level B involves construction of a settling pond outside the
quarry at surface level and construction of a sump discharge
line to the pond. Berm and dam materials are obtained from
the excavation of the pond. The earth moving equipment is
that used in the mining operation. The settling pond
discharges by gravity. The existing quarry floor sump and
sump pump are used. The existing sump discharge line is
used and additions are made to it.
Level C involves the same new construction as Level B,
except anionic chemical flocculant is added to the sump
discharge to the settling pond.
Level D is the same as Level C, except the pH is adjusted by
chemical addition from pH 5 to pH 7.
BASIS FOR COST
There are 4800 facilities in this category of which 59
percent wash their product. Of those that wash their
product, an estimated 68 percent practice recycle of process
water. Thirteen percent of the facilities do not have mine
water. There are 1920 crushed stone facilities representing
production of 307 million kkg (338 million tons) that are
319
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TABLE 16 A
COST-BENEFIT ANALYSIS FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUBCATEGORY CRUSHED STONE.
PLANT SIZE 1,455
PLANT AGE_
DKf
METRIC TONS PER *a»5 OF c.s.
(1,600
YEARS
PLANT LOCATION 1020
PiaipOUt = 70 GEM
sau aays/yx. operation
63,750 metric tons/yr
INVESTED CAPITAL COSTS'.
TOTAL
ANNUAL CAPITAL RECOVERY-
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 3 M (EXCLUDING .
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/METRIC TON C.S.
WASTE LOAD PARAMETERS
TSS, mq/1
PH
Acidity, mcr/1 CaCOs
RAW
WASTE
LOAD-
200
5.0
190
LEVEL
A
folfttk
1,492
176 ..
1,015
«
1,191
0.003
30
5.0
190 .
B
3,485
411
1,023
»
1,434
0.004
<30
5.0
190
C
15,800
2.419
4,832
11
7,270
0.020
<30
5.0
190
0
24,700
3,867
8,879
22
12,770
0.035
<30
6-9
0
E
LEVEL DESCRIPTION:
A " added 2nd stage suitp, rock filter
B = settling pcnd at surface
C = B + floe treatitent
D = C + pH control
Vll/77
320
-------
COST-1
TABLE 16 B
ANALYSIS FOR A REPRESENTATIVE PLANT
(ALL COSTS ARE CUMULATIVE)
SUBCATEGORY CRUSHED STCME
PLANT SIZE 1.451
DAY
PLANT AGE .
600 GEM puitpout
YEARS
METRIC TONS PER »«a8 OF c.s.
PLANT LOCATION 1022
(1,600 -H?D)
362,750 metric tons/yr
INVESTED CAPITAL COSTS:
TOTAL
•ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS:
ANNUAL 0 a M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
COST/METRIC TON C-S-
WASTE LOAD PARAMETERS
( teq^mBtriootagaofcnoooocxxxx )
TSS, mj/1
PH'
Acidity, ncr/1 CaCOa
RAW
WASTE
LOAD'
200
5.0
190
LEVEL
A
*tttt&
4,654
549
1,125
-
1,674
0.005
30
5.0
190
B
17,455
2,060
1,162
-
3,222
0.009
<30
5.0
190
C
41,200
5,923
6,247
96
12,266
0.034
<30
5.0
190
D
57,680
8,616
13,252
192
22,060
0.061
<30
6-9
0
E
LEVEL DESCRIPTION:
A = 2nd Stage sunp, rock filter added
B = Settling pond at surface
C = B + floe treatment
D = C + pH control
1/11/77
321
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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 no.n-con tact
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 10* kkg/yr
(1«»3 x 10« 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 227,000 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.
323
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TM£ 17
CONSTRUCTION SAND AND GRAVEL (WET PROCESS)
TREAT1W COSTS
PLANT SIZE 227,000
PLANT AGE 5 YEARS
KKG
PER YEAR OF product
PLANT LOCATION "eqr 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/ RKfJ product
WASTE LOAD PARAMETERS
(kg/ VV°- °f Product )
Suspended Solids
RAW
WASTE
LOAD
100
LEVEL
A
(MIN)
0
0
0
0
0
0
100
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
..,. i-.~
LEVEL DESCRIPTION:
All costs are cumulative.
A — direct discharge
B — settling, discharge
C — settling, recycle
D ~ two silt removal ponds, settling pond, recycle
E — flocculant, 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
324
-------
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
Level D: Two silt removal ponds of 0.04 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 4 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
Leyel 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
4 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.
325
-------
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
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 a00
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 equipment 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 require 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.
326
-------
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.
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 recycling 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 subcategory 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 required in an urban environ-
ment 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
required represents about 7.4 million dollars.
The 107 facilities which 4re 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.
327
-------
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).
RIVER,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.
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 50JJ 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).
328
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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 (44r000 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 - $10rOOO/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
329
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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 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 » 1055 interest) = $7000
pump costs (5 yr life a 1056 interest) = 1500
piping costs (10 yr life 3108 interest) = 2200
total $10,700
Operating Costs
maintenance costs 8 2% of capital = $1600
power cost a $.02 per kwh = 2000
taxes and insurance 3 2% of
capital = 1600
total $5200
330
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TABLE 18
INDUSTRIAL SAM) (WET PROCESS) TREAT1OT COSTS
PLANT SIZE 180,000
PLANT AGE *0 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
(Ha/ vVp °f Product )
Suspended Solids
RAW
WASTE
LOAD
35
LEVEL
A
(MIN)
69,000
8,000
£800
1,000
1 1,800
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
LEVEL DESCRIPTION:
All costs are cumulative.
A — settle,dlscharge
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.
331
-------
Level 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 a 1056) = $25,200
Operating Costs
chemicals $11,000
maintenance S 556
of capital 7,800
power 2,000
taxes and insurance
S 2% of capital 3,100
total • $23,900
The facilities surveyed for this subcategory 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 A 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.
332
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These three flotation processes have been subdivided into
two, subcategories; (1) acid and alkaline flotation and
(2) hydrofluoric acid flotation. Subcategory (1) is
discussed in this subsection and subcategory (2) in the
following subsection.
Four surveyed acid flotation facilities havp 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.
Capital Costs
lime storage and feed system - $75,000
reaction tank - 40,000
pumps and piping - 20,000
Total $ 135,000
annualized capital cost (10 yr life a 10ft) $22,000
Operating Costs
chemical costs - $11,000
maintenance 3> 5% of capital - 7,300
power - 2,000
taxes and insurance 3) 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.
333
-------
TABLE 19
INDUSTRIAL SAND (ACID AND ALKHLINE PROCESS)
TREATTeiT COSTS
PLANT SIZE 180,000
KKG
PER YEAR.OF product
PLANT AGE 30 YEARS PLANT LOCATION southeastern U.S.
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 product
WASTE LOAD PARAMETERS
(ka/ kks of product )
Suspended Solids
RAW
WASTE
LOAD
TOO
LEVEL
A
(MIN)
115,000
18,700
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.
334
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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
questionable quality for total recycle. Estimated costs for
partial recycle are given in Table 20, Only one such
facility is known.
Cost Basis For Table 201
(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.
Capital Costs
pond - 1/2 acre x 10 ft depth a $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 8 10% interest)
$120,000 x .1629 = $19,500
Operating Costs
maintenance S 5% of capital = $6,000
chemicals, lime 3> $20/ton = 11,000
power a $.0 2/kwh = 2,000
taxes and insurance 82%
of capital = 2,400
total $23,400
335
-------
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/ YXG product
WASTE LOAD PARAMETERS
(kg/ kkg 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 Jn 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.
336
-------
ACID LEACHING
Treatment cost for this process is not completed at this
time, and no treatment recommendation will be made till
further study is made.
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
($0.045/ton).
MINE DRAINAGE
In all of the subcategories some facilities find it
necessary to pump out their quarries 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.
337
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ASPHALT1C 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 ($1/ton) of gilsonite produced. The cost
estimates are given in Table 21. The only gilsonite
facility is located in Utah. All costs are specific for
this facility.
Level A
Capital Costs
pond cost, ^/hectare ($/acre) : 24,700 (10,000)
settling pond area, hectares (acres): 0.8 (2)
pump, piping, ditching: $5,000
Operating and Maintenance 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
a H% of investment 10,000
power 3 $.01/kw-hr 500
taxes and insurance
8 2% of investment 5,000
338
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TABLE 21
GILSONITE TREAT1W 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 & M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POV/ER
TOTAL ANNUAL COSTS $
COST/ KKG Gilsomte
WASTE LOAD PARAMETERS
Mine Pumpout:
Suspended Sol ids,mg/liter
BOD, mg/liter
Process Water;
Suspended Solids, mg/lifei
BOD, mg/liter
RAW
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
LEVEL DESCRIPTION:
A — pond settling of suspended solids in mine pumpout; no treatment of process water
(present minimum).
B — combining of mine pumpout and process water followed by pond settling, filtration
and partial recycle. Discharge from recycle to be used .for on-property irrigation.
339
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ASBESTOS AND WOLLASTONITE
Asbestos is niined 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 annual!zed 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 groundwater 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.
340
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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 ac-
cumulates, 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 by 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 40 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
341
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TABLE 22
VERMICULITE TREATOTT COSTS
PLANT SIZE 160,000
KKG
PER YEAR OF product
PLANT AGE 30 YEARS PLANT LOCATION Montana or South Carol ma
'INVESTED CAPITAL COSTS: •$
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 a M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POV/ER
TOTAL ANNUAL COSTS
$
COST/ KKG product
WASTE LOAD PARAMETERS
(ka/ vTr °f 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.
342
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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 a
$10,000/acre and operating costs of $750/yr).
WET BENEPICIATION 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.
343
-------
TABLE 23
MICA TOTOENT C
PLANT SIZE 16,360
PLANT AGE27 YEARS
KKG
PLANT LOCATION.
PER YEAR.OF Mica
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 6
9
COST/ KKG Mica
WASTE LOAD PARAMETERS
(ha/ kkg of Mica )
Suspended Solids
PH
RAW
WASTE
LOAD
2,100
~
LEVEL
A
(MIN)
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 cost? 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)
344
-------
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)
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 = .1174
Annual investment costs = $17,610/yr
Operating Costs
Solid wastes handling a $0.30/ton = $15,000
Pond cleaning a $0.50/ton = 19,000
Maintenance = 10,000
Power = 2,000
Labor = 3,000
Taxes and insurance a 2% of
capital = 3,000
Total $52,000
345
-------
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
Operating Costs
Solid wastes handling 3 $0.30/ton - $15,000
Pond cleaning 9 $0.50/ton = 19,000
Maintenance = 15,000
Chemicals v = 5,000
Power = 3,000
Labor (misc) = 5,000
Taxes and insurance a 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 = 25,000
Total $300,000
Annual investment costs = $35,220
346
-------
Operating Costs
Solids wastes handling 3 $0.30/ton = $15,000
Pond 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
required.
Capital Costs
Thickener - 15 meter (50 ft.) diameter = $150,000
Filter system installed = 35,000
Pumps, tanks, piping, collection = 50,000
Conveyor = 5,000
Building = 5,000
Total $245,000
At 10 yr life and 10% interest rate
Capital recovery factor = .1627
Annual investment costs = $39,862
Operating Costs
Solids wastes handling ® $0.30/ton = $26,400
Maintenance = 20,000
Chemicals =20,000
Power = 5,000
Labor = 3,000
Taxes and insurance 92%
of capital = 5,000
Total $79,400
347
-------
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 thia 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 required.
348
-------
BARITE
Of the twenty-seven known significant U.S. facilities
producing barite ore or ground foarite, 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
3U9
-------
TABLE 24
BARI7E (WET PROCESS) TREATTtNT COSTS
PLANT SIZE I8'°°°
KKG
PLANT AGE M YEARS PLANT LOCATION
PER YEAR -OF__
Missouri or Nevada
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 Barite
WASTE LOAD PARAMETERS
(mg/liter)
Suspended solids
Iron
Lead
PH
RAW
WASTE
LOAD
LEVEL
A
(MIN)
180,000
21, 150
10,000
10,000
41,150
2.26
15-327*
0.04-8.4"
3.03-2.0*
6-9*
B
260,000
30,500
16,400
10,000
56,900
3.13
25*
1.0*
O.I*
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 peripds of heavy rainfall
A. Complete recycle except in times of heavy rainfall
B . A plus treatment of all discharged water with lime and flocculants
C. Complete recycle - no discharge at all times (ability to achieve this level
depends on local terrain - not all plants are capable of attaining zero discharge)
All costs are,cumulative.
350
-------
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 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, S/hectare ($/acre)
(a) tailings ponds: 12,350 (5,000)
(b) clarification ponds: 7,400 (3,000)
Pond areas, hectares (acres)
(a) tailings ponds: 8.1 (20)
(b) clarification ponds: 8.1 (20)
Pumps and pipes: $50,000
Operating and Maintenance Costs
Power unit cost: $100/HP-yr
Pond maintenance: 2% of pond investment
Pump and piping maintenance: 6% of non-pond investment
Taxes and insurance: 2% of total investment
Flocculants: $2.20/kg ($1.00/lb)
Lime: $22/kkg ($20/ton)
FLOTATION OPERATIONS
Flotation is used on either beneficiated 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
351
-------
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.
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 by 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.
Capital 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 TO6 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.
352
-------
TABLE 25
BARITC (FU3TATION PROCESS) TREATOTT COSTS
PLANT SIZE
70,000
KKG
PER YEAR OF Barite
PLANT AGE 33 YEARS PLANT LOCATION Missouri, Nevada, Georgia
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/ KTTC Barite
WASTE LOAD PARAMETERS
(mg/liter)
Suspended Solids
PH
RAW
WASTE
LOAD
:50,000
-
LEVEL
A
(MIN)
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:
f^.Pond settling of solfds plus recycle of water 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 adfust pH and reduce
suspended solids
D. B plus additional pond capacity for total impoundment (requires favorable local terrain)
353
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FLUORSPAR
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
354
-------
FLUORSPAR
TABLE 26
PROCESS) TREATMENT COSTS
PLANT SIZE
40,000
KKG PER YEAR/OF fiuorsPar
PLANT AGE 8 YEARS PLANT LOCATION Midwest
INVESTED CAPITAL COSTS! $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 9 M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KK6 fluorspar
WASTE LOAD PARAMETERS
(ka/ kkp of fluorspar )
Suspended solids
Dissolved Fluoride
Lead
Zinc
pH
RAW
WASTE
LOAD
340
0.04
- •
-
-
LEVEL
A
(WIN)
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
LEVEL DESCRIPTION:
A. Spiral classifier followed by small pond with discharge
B. Thickener plus total recycle
All costs are cumulative.
355
-------
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.
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: 255 of investment
Flocculating chemicals: $2.20/kg ($1/lb)
Lime: $22/kkg ($20/ton)
Alum: $55/kkg ($50/ton)
356
-------
TABLE 27
FLUORSPAR (FLOTATION PROCESS) TREATS COSTS
PLANT SIZE 40,000
KKG
PLANT AGE l5 YEARS PLANT LOCATION
PER YEAR OF fluorspar
Midwest
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/ „„ of product
WASTE LOAD PARAMETERS
(kq/ 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
185,000
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
1 0,000
101 ,400
2.54
0.2-0.4
0.05-0.1
D
-.
E
LEVEL DESCRIPTION:
A - pond settling and discharge
B r- A plus treatment with flocculants
C - A plus alum treatment
All costs are cumulative.
357
-------
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.
358
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SALINES FROM BRINE 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: 2% of pond investment
Pump and piping maintenance: 6% of pump and piping investment
Power: $100/HP-yr
Taxes and insurance: 2% of total investment
359
-------
TABLE 28
BORATES TREATTejT COSTS
PLANT SIZE 1,000,000
KKG
PER YEAR/OF Bora*es
PLANT AGE t7 YEARS PLANT LOCATION Cqliforniq
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 Berates
WASTE LOAD PARAMETERS
(ka/' H,» of Berates )
Solid wastes (insol .)
Soluble wastes
RAW
WASTE
LOAD
800
2.5
LEVEL
A
(MIN)
?,500,000
293,500
120,000
30,000
443,500
0.44
0
0
B
C
D
E
LEVEL DESCRIPTION:
A - evaporation of all wastewater in ponds.
All costs are cumulative.
360
-------
POTASH
Potash is produced in four different locations by four dif-
ferent 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 Costs
Maintenance, taxes and insurance: U% 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: 8% of investment
Taxes and insurance: 2% of investment
Power: $ 10 0/HP-yr
361
-------
TABl£29
POTASH (CARLSBAD OPERAtlONS) TREATMENT COSTS
PLANT SIZE
PLANT AGE
500,000
KKG
30
YEARS
PLANT LOCATION
PER YEAR OF_
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 Potash
WASTE LOAD PARAMETERS
(kg/ fcke 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 DESCRIPTION:
A - Evaporation ponds
*as brine
All costs are cumulative.
362
-------
TABLE 30
POTASH (MQAB OPERATIONS) TREATOTT COSTS
PLANT SIZE 200'000
KKG
PLANT AGE
10
YEARS
PLANT LOCATION.
PER YEAR OF Potash
Utah
INVESTED CAPITAL COSTS; $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 S M (EXCLUDING
POV/ER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS
$
COST/ KKG potash
WASTE LOAD PARAMETERS
(kg/ M,C 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-tand evaporation
All costs are cumulative.
363
-------
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, $/hectare ($/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
364
-------
TABLE 31
TRDNA TREATOU COSTS
PLANT SIZE 1,000,000
KKG
PLANT AGE 15 YEARS
PLANT LOCATION
PER YEAR OF Soda Ash
Wyoming
INVESTED CAPITAL COSTS'. $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL o G M (EXCLUDING
POWER AND ENERGY )
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG soda ash
WASTE LOAD PARAMETERS
(Kg/ kkg 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
LEVEL DESCRIPTION:
A — Evaporation ponds with small discharge
B — Evaporation ponds with no discharge
All costs are cumulative.
365
-------
Operating and Maintenance Costs
Pond maintenance: 2% of pond investment
Pump and piping maintenance: 6% of pond investment
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.
366
-------
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) .
367
-------
HOCK 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-1- 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 maintenances 1056 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.
368
-------
TABLE 32
ROCK SALT TREATTBTT 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
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ KKG sa|t
WASTE LOAD PARAMETERS
(kg/ irirp of salt )
Suspended solids
D1s$p1ved solids
RAW
WASTE
LOAD
0-0.9
LEVEL
A
(MIN)
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
87150
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 DESCRIPTION:
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
369
-------
PHOSPHATE ROCK
Phosphate ore is mined in four different regions of the
U.S.:
Florida: 7856 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. Raw wastes, sand, and small particle sized
slimes in the process raw wastes exceed the quantity 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
ma'ssive 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
(4) 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
370
-------
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 separately. Rainwater runoff is also
treated separately, if needed.
(2) Evaporation-rainfall imbalances are more than counter-
balanced 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.
371
-------
TABLE 33
PHOSPHATE ROCK (EASTERN) TREATMENT COSTS
PLANT SIZE 2,000,000
PLANT AGE 15 YEARS
PER YEAR-OF product
PLANT LOCATION Florida-North Carolina-Tennessee
'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/ _ product
WASTE LOAD PARAMETERS
(mg/lirer)
Suspended Solids
Dissolved Fluoride
Phosphorus (total)
RAW
WASTE
LOAD
LEVEL
A
(MIN)
8,000,000
804,000
360,000
240,000
T/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
12,000,000
1,560,000
429,000
335,000
2,324,000
1.16
0
0
0
D
E
LEVEL DESCRIPTION:
* 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.
372
-------
Capital Costs
Pond .cost, $/hectare ($/acre) : 17r300 (7,000)
Pond area, hectares (acres): 400 (1,000)
Pumps and piping: $1,000,000
Operating and Maintenance Costs
Labor and maintenance: 2.5% 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 34 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.
All facilities in this subcategory 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) j 4,900 (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
373
-------
TABLE 34
PHOSPHATE ROCK (WESIERN) TREATOfl" 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 POV/ER
TOTAL ANNUAL COSTS 6
9
COST/ y^ft _ product
WASTE LOAD PARAMETERS
(kg/ ^8 of product )
SuspenHed solids
Fluoride (as Ion)
Phosphorus (fatal)
RAW
WASTE
LOAD
1700
-•
- •
LEVEL
A
(MIN)
850,000
93,500
38,500
50,000
182,000
0.36
<0.05
<0.001
<0j001
B
1,250,000
140,500
56,500
75,000
272/500
0.54
0
0
0
C
D
E
LEVEL DESCRIPTION:
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.
374
-------
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.
375
-------
SULFUR (FRASCH PROCESS)
There are two subcategories 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 bleed-
water .
(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
376
-------
TABl£35
SULFUR (ANHYDRITE) TREATICMT 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
WASTE LOAD PARAMETERS
(kg/ kkg of sulfur }
Wafer softener sludge
Suspended solids
Dissolved solids
RAW
WASTE
LOAD
12.5
-
21 .0-
43.7
LEVEL
A
(MIN)
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.
377
-------
Operating and Maintenance Costs
'-*" :1 — - ™^™-««—• . (
Bleedwater volume, I/day (mgd): 18.9 x 10* (5.0)
Bleedwater treatment, $/1,000 liters (gallons): $0.09 ($0.35)
The energy and power costs were supplied by facility 2020
ON-SHORE SALT DOME 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 techno-
logy, 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, quite 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
378
-------
TABLE 36
SULFUR (ON-SHORE SALT DOPE) TREATMT COSTS
PLANT SIZE
500,000
PLANT AGE 26 YEARS
KKG
PER YEAR OF sulfur
PLANT LOCATION Louisiana-East Texas
INVESTED CAPITAL COSTS:
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 a M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND PO\VER
TOTAL ANNUAL COSTS $
COST/ KKG sulfur
WASTE LOAD PARAMETERS
Sulfide, mo/liter
Suspended solids, mg/litcr
RAW
WASTE
LOAD
600-
IDQ.Q.
<50
LEVEL
A
(WIN)
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
P-81,
/
<1
<50
D
3,200,000
375,700
102,000
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
0
<50
LEVEL DESCRIPTION:
A — Flashing of hydrogen sulfide from bleedwoter
B — Spray aeration
C — Flue gas stripping reaction plus ponding
D — Large oxidation and settling ponds
E — Aeration in small ponds followed by mixing of partially treated.bleedsvater with
10-20 times its volume of oxygen-containing water
F — Chemical treatment with sulfurous acid
G— Chemical treatment with chlorine •
379
-------
through F were taken from industry supplied values. The
chlorine costs for Level G are $110/kkg ($100/ton).
OFF-SHORE SALT DOME 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 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
20/5 of direct costs
Labor and maintenance: 8% of investment
Power: $100/HP-hr
Chlorine, dollars/kkg (dollars/ton): 110 (100)
Taxes and insurance: 2% of investment costs
380
-------
TABLE 37
SULFUR (OFF-SHOE SALT DOE) TREATOTT COSTS
PLANT SIZE
1,000,000
KKG
PER YEAR -OF sulfur
PLANT AGE 14 YEARS PLANT LOCATION Off-Shore Louisiana
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 su|fur
WASTE LOAD PARAMETERS
{kg/ p-p-g nf sulfur )
Suspended Solids
Sul fides
RAW
WASTE
LOAD
0.3
5.5
LEVEL
A
(WIN)
0
0
0
0
0
0
0.3
5.5
B
1 3/50,000
2,237,000
1,385,000
200,000
3,822,000
3.82
0.2
0.03
C
7,920,000
1,288,600
6,212,000
100,000
7,600/500
7.60
0.2
0.03
D
E
•
LEVEL DESCRIPTION:
A — Use of oxygen in seawafer to oxidize sulfides
B — All bleedwater pumped to shore followed by on-shore ponding and mixing
with ambient water to oxidize sul fides
C — Off-shore chemical oxidation of sulfides with chlorine
All costs are cumulative.
381
-------
MINERAL 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: H% of investment
Power: $ 10 0/HP-yr
Taxes and insurance: 2% of investment
382
-------
TABLE 38
MINERAL PIGPENTS TREATOH 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 a M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL COSTS $
COST/ vyG product
WASTE LOAD PARAMETERS
{kg/- kkS of product )
Suspended Solids
RAW
WASTE
LOAD
wm^
LEVEL
A
(MIN)
15,000
1,750
900
500
3,250
1.08
2.3
8
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.
383
-------
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-products 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) : 7,400 (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: $100,000/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.
384
-------
TABLE 39
LITHIUM MIERALS TREATOiT COSTS
PLANT AGE 15 YEARS PLANT LOCATION North Carolina
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 ppncentrate
WASTE LOAD PARAMETERS
spodumene
(kg/ y^e of . concentrate
Suspended Solids
RAW
V/ASTE
LOAD
1R50-
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 PESCR/PT/CW:
A — Ponding of wastewater to remove suspended solids plus recycle of
process wastewater
B — Level A plus segregation and treatment of additional wastewater streams plus
recycle of all process wastewater
All costs are cumulative.
385
-------
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.
PULLER'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 HO 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
taxes, 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)
386
-------
TABLED
ATTOPULGITC TREA71W COSTS
PLANT SIZE 200,000
PLANT AGE 60 YEARS
KKG PER YEAR OF Atrapulgite
PLANT LOCATION
Georgia-North Florida Region
INVESTED CAPITAL COSTS; $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 3 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
OjOl-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 set-fling
B — A plus flocculating agents
C — B plus recycle to process
All costs are cumulative.
387
-------
TABLE 41
ITOTOLLONITE TREATIW COSTS
PLANT SIZE
182,000
KKG
PLANT AGE 10 YEARS
PLANT LOCATION
PER YEAR OF Montmorillonire
Georgia
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 Montomorflloniff
WASTE LOAD PARAMETERS
(kg/kkg of montmoriHo't
TSS
PH
RAW
WASTE
LOAD
ite)
LEVEL
A
(MIN)
60,000
7,000
30,900
200
38,100
0.21
0.3
6-9
B
65,000
7,900
32,900
200
41 ,000
0.22
0.05
6-9
C
80,000
9,400
32,300
300
43,000
0.24
0
-
D
E
LEVEL DESCRIPTION:
A — pond settling of scrubber wafer
B — A plus flocculating agents
C — B plus recycle to process
All costs are cumulative.
388
-------
TABLE 42
IWIHMLLJONITE MINE WATER TREAWNT COSTS
PLANT SIZE
PLANT AGE
1.82,000
YEARS
KKG
PLANT LOCATION
PER YEAR OF Montmorillonite
Georgia
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 Montmorillonite
WASTE LOAD PARAMETERS
TSS, mg/liter
RAW
WASTE
LOAD
LEVEL
A
(MIN)
0
0
0
0
0
0
200—
5rOOO
B
60,000
15,800
12,300
3,000
32,300
0.17
2UU~
2T000
c
62,000
16,300
32,300
3,000
51,800
0.28
<50
D
E
LEVEL DESCRIPTION:
A — no treatment
B — pond settling
C •— B plus flocculating agents
All costs are cumulative.
389
-------
Process Settling pond area, hectares (acres):2 (5)
Pumps and pipes: $10,000
Operating and Maintenance Costs
Energy unit cost: $0.01/kwh
Labor rate assumed: $10,000/yr
Cost Basis for Table 41
Capital Costs
Pond cost, $/hectare ($/acre) :24,700 (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
390
-------
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 43 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: $22/kkg ($20/ton)
Flocculating agent: $2.2/kg ($1/lb)
Energy unit cost: $0.01/kwh
Maintenance: $10,000-11,000/yr
391
-------
TABLED
WET PROCESS KflOLIN TREATTefT COSTS
PLANT SIZE 450,000
PLANT AGE 30 YEARS
I&G
PER YEAR OF Kaolin
PLANT LOCATION Georgia-South Carolina
INVESTED CAPITAL COSTS: $
TOTAL
ANNUAL CAPITAL RECOVERY
OPERATING AND MAINTENANCE
COSTS: $
ANNUAL 0 8 M (EXCLUDING
POWER AND ENERGY)
ANNUAL ENERGY AND POWER
TOTAL ANNUAL -COSTS $
COST/ KKG of Kaolin
WASTE LOAD PARAMETERS
mg/1
TSS
Dissolved zinc
pH
RAW
WASTE
LOAD
1000C
160
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.)
392
-------
BALL CIAY
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 yearso Age has not been found to be a significant
factor on costs. Ball 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 1 ,000/yr
393
-------
TABLED
BALL CLAY TREATMENT 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 AND POWER
TOTAL ANNUAL COSTS $
COST/kkg of Ball Clay
WASTE LOAD PARAMETERS
{ka/kke of ball clay )
TSS
pH
RAW
WASTE
LOAD
LEVEL
A
(MIN)
897000
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 flocculating agent
C — closed cycle operation (satisfactory only for scrubbers and cooling water)
394
-------
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 subcategory involving major treatment and cost is wet
beneficiation of feldspar ore.
After initial scalpings with screens, hydrocyclones or other
such devices to remove the large particle sizes, the smaller
particle sizes are removed by (1) settling ponds or
(2) mechanical thickeners, clarifiers and filters. Often
the method selected depends on the amount and type of land
available for treatment facilities. Where sufficient flat
land is available ponds are usually preferred.
Unfortunately, most of the industry is located in hill
country and flat land is not available. Therefore,
thickeners and filters are often used. 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 15,700 to 154,000 kkg/yr
(50,100-170,000 ton/yr). The representative facility is
90,900 kkg/yr (100,000 ton/yr). The range of capital costs
395
-------
TABLE 45
WET PROCESS FELDSPAR TREATTBTr COSTS
PLANT SIZE 90,900
PLANT AGE TO YEARS
KKG
PLANT LOCATION
PER YEAR OF Feldspar
Eastern U.S.
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 Feldsoar
WASTE LOAD PARAMETERS
(ko/ kkg of ore )
Suspended Solids
Fluoride
pH
RAW
WASTE
LOAD
26fen
0.22-
n . 95
—
LEVEL
A
(MIN)
115,000
18,700
107,500
2,000
128,200
1.41
0.6
0.2
6-9
B
260,000
42,100
132,500
2,000
176,600
1.95
0.3
0.1
6-9
C
375,000
60,800
157,500
2,000
220,300
2.42
0.3
0.03
6-9
D
185,000
30,100
118,500
4,000
152,600
1.68
0.3-3
0.2
6-9
E
415,000
70,800
156,500
6,000
233,300
2.56
0.1-0.3
0.03
6-9
LEVEL DESCRIPTION:
All .costs are cumulative.
A — settling pond for suspended solids removal, no fluoride treatment.
B — larger settling ponds plus internal recycle of some fluoride-containing water plus
flocculation agents.
C — B plus segregation and separate lime treatment of Fluoride water.
D — present treatment by thickeners and filters plus lime treatment for fluoride.
E — D plus segregation and separate lime treatment of fluoride water plus improved
suspended solids treatment by clarifier installation.
396
-------
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.
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 taxes, 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); 0.4-0.8 (1-2)
Thickeners, filters, clarifiers: 0-$50,000
Solids handling equipment: $40,000-50,000
Chemical metering equipment: 0-$50,000
Operating and Maintenance Costs
Other solid waste disposal costs: 0-$0.5/ton
Treatment chemicals: $10,000-25,000/yr
Energy unit cost: $0.01/kwh
Monitoring: 0-$15,000/yr
397
-------
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 subcategory 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 is, 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: $14,600/yr
Pipes: $3,300/yr
Energy unit cost: $0.01/kwh
Pumps: $1,200/yr
Labor: $3,000/yr
Maintenance: $16,900/yr
398
-------
TABLE 46
MITE 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 8 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
(MIN)
80,000
9,700
75,000
1,000
85,700
1.90
3
6-9
B
157,400
19,100
108,100
1 ,400
128,600
2.83
0
-
e
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.
399
-------
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-percolation pond. Capital costs for this
treatment are $300,000 with operation/maintenance costs of
$15,000/yr plus annual capital investment costs of $35,220.
SHALE AND COMMON CLAY
No water is used in either 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 by 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 $0.48/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
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Aplite is produced by two facilities which, are 17 and 41
years old. Age has not been found to be a significant cost
variance factor. Both aplite facilities a-re 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 O 6 M cost: $1,900/yr
Maintenance:$4,500-16,500/yr
401
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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
Rain water and ground water seepage often make it necessary
to pumpout mine water. The only treatment normally needed
for this water is settling ponds for suspended solids.
Ponds are usually small, one acre or less. Costs for this
treatment are in the range of $0.01 to $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
D.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
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TABLE 47
WET PROCESS TALC MINERALS TREATMENT COSTS-
PLANT SIZE 45,000
PLANT AGE 25 YEARS
KKG
PER YEAR OF tofc minerals
PLANT LOCATION Eastern U.S.
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 of products
WASTE LOAD PARAMETERS
(k
-------
than capital recovery, taxes and insurance are approximately
proportional to size.
Capital Costs
Land cost, $/hectare ($/acre): 24,500 (10,000)
Mine pumpout, settling pond area, hectares (acres):
up to O.H (up to 1)
Process settling pond ar:ea, hectares (acres) : 2 (5)
Pumps and pipes: $15,000
Chemical treatment equipment: $35,000
Operating and Maintenance Costs
Treatment chemicals
Lime: $22/kkg ($20/ton)
Energy cost: $1,000-2,000/yr
Maintenance: $5,000/yr
Labor: $3,000-10,000/yr
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GARNET
There are three garnet producers in the U.S., two in Idaho
and one in New York State. Two basic types of processing
are used: (1) wet washing and classifying of the ore, and
(2) heavy media and froth flotation. Washing and
classifying facilities have already incurred estimated waste
water treatment costs of $0.16 per 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 subcategory. Due to process and size differences,
treatment costs must be calculated on an individual basis.
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TRIPOLI
There are several tripoli producers in the United States.
The production is dry both at the facilities and the mines.
One small facility has installed a wet scrubber. There is
only one facility in this subcategory that has any process
waste water. This is only from a special process producing
10 percent of that facility's production. Therefore, there
are no cost variances due to age, location or size.
DIATOMITE
Diatomite is mined and processed in the western U.S. Both
mining and processing are practically dry operations.
Evaporation ponds are used for waste disposal in all cases.
The selected technology of partial .recycle and chemical
treatment is practiced at the better facilities. All
facilities are currently employing settling and neutra-
lization.
GRAPHITE
There is only one producer of natural graphite in the United
States. For this mine and processing facility, mine
drainage, settling pond seepage and process water are
treated for suspended solids, iron removal and pH level.
The pH level and iron precipitation are controlled by lime
addition. The precipitated iron and other suspended solids
are removed in the settling pond and the treated waste water
discharged. Present treatment costs are approximately $20-
25/kkg graphite produced.
JADE
The jade industry is very small and involves very little
waste water. One facility 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.
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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
(CER Title 40, Chapter 1; Part 241) may be used as guidance
for acceptable land disposal techniques.
For those waste materials considered to be hazardous,
disposal will require special precautions. In order to
ensure long-term protection of public health and the
environment, special preparation and pretreatmerit may be
required prior to disposal. If land disposal is to be
practiced, these sites must not allow movement of pollutants
such as fluoride and radium-226 to either ground or surface
water. Sites should be selected that have natural soil and
geological conditions to prevent such contamination or, if
such conditions do not exist, artificial means (e.g.,
liners) must be provided to ensure long-term protection of
the environment from hazardous materials. Where
appropriate, the location of solid hazardous materials
disposal sites should be permanently recorded in the
appropriate office of the legal jurisdiction in which the
site is located. In summary, the solid wastes and sludges
from the mineral mining industry waste water treatments are
very large in quantity. Since these industries generally
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have sufficient space and earth-moving capabilities, they
manage it with greater ease than most other industries.
If the best practicable control technology regulations were
promulgated for every subcategory, the added annual energy
requirements would be approximately 555 million kw-hours.
Much of this added energy requirement would be attributable
to wet processing of crushed stone, phosphate rock and
sulfur (on-shore salt dome).
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SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH THE
APPLICATION OF THE
BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE
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 mineral mining
industry, this level of technology was assessed based on the
average of the best 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.
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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. No effluent limitation of non-contact
cooling presently exists.
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. Pit pumpage of ground water, seepage and
precipitation or surface runoff entering the active mine
workings is an example of mine dewatering. The recommended
pH of mine dewatering discharges is between 6.0 & 9.0. This
pH range, is not to supersede state water quality criteria
for receiving waters with 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
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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.
WASTE WATER GUIDELINES AND LIMITATIONS
DIMENSION STONE
The limitation which can be attained based on 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 limitations which can be achieved are not
more than 30 mg/1 TSS. 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)
The limitation which can be attained based on the 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 limitations set forth below are based on the use of the
best practicable control technology currently available.
Discharge of process generated waste water pollutants from
facilities that recycle waste water for use in processing,
are not to exceed the following limitations.
Effluent Effluent,
Characteri stic Limitations
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Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
Except as provided for in paragraph (1) , there is to be no
discharge of process generated waste water pollutants into
navigable waters.
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.
A survey was conducted by The National Limestone Institute
of their participating members to determine, among other
things, the number of crushed stone facilities that actually
recycle all process generated waste water. Nineteen percent
of the 104 wet processing plants surveyed reported that they
presently meet the requirements of no discharge of process
generated waste water and sixty-eight percent of the wet
processors practice some recycle.
CRUSHED STONE (FLOTATION PROCESS)
The limitations set forth below are based on the best
practicable control technology currently available.
Discharge of process generated waste water pollutants from
facilities that recycle waste water for use in processing,
is not to exceed the following limitations.
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
Except as provided for in paragraph (1), there is to be no
discharge of process generated waste water pollutants into
navigable waters. Facility 1975 is currently meeting this
requirement. Facility 3069 is recycling about 70 percent of
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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 limitations which can be achieved are:
Effluent Effluent
Characterj stic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
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 for 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, temporarily halting pit pumpout to allow the
water to clear, use of flocculants on an intermittent basis,
or construction of a settling pond will cure muddy quarry
water problems.
CONSTRUCTION SAND AND GRAVEL (DRY)
The limitation which can be attained based on 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 limitations set forth below are based on the use of the
best practicable control technology currently available.
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Discharge of process generated waste water pollutants from
facilities that recycle waste water for use in processing,
is not to exceed the following limitations.
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6,0 to 9.0.
Except as provided for in paragraph (1) , there is to be
discharge of process generated waste water pollutants into
navigable waters. 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)f that is ponds entirely
owned or leased from the pond owner. These frequently are
flooded dry pits. Process water should be recycled from
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.
CONSTRUCTION SAND AND GRAVEL
(MINE DEWATERING)
Mine dewatering limitations which can be achieved are:
Effluent Effluent
Characteri stic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
Except for emergency pumping after flooding, mine dewatering
is unusual in this subcategory. Pits experiencing ground
water flooding are usually allowed to fill and the deposit
is dredged. This is in contrast to stone quarries where
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dredging is not possible for hard rock. In cases where it
might be practiced, a sump arrangement like that for stone
quarries 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
limitations set forth below are based on the use of the best
practicable control technology currently available for the
discharge of process water not originating from the dredge
pump.
Discharge of process generated waste water pollutants from
facilities that recycle waste water for use in processing,
are not to exceed the following limitations.
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
Except as provided for in paragraph (1), there is to be no
discharge of process generated waste water pollutants into
navigable waters.
This limit can be achieved by ponding and/or recycle of all
non-dredge pumped process waste water. More than half this
subcategory has achieved this level of technology for
on-land treatment. No limits are recommended 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„«
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INDUSTRIAL SAND (DRY PROCESS)
The limitation which can be attained based on 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 limitations set forth below are based on the use of the
best practicable control technology currently available.
Discharge of process generated waste water pollutants from
facilities that recycle waste water for use in processing,
are not to exceed the following limitations.
Effluent Effluent
Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
Except as provided for in paragraph (1), there is to be no
discharge of process generated waste water pollutants into
navigable waters.
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.
INDUSTRIAL SAND (ACID AND ALKALI FLOTATION PROCESS)
The limitations set forth below are based on the use of the
best practicable control technology currently available.
Discharge of process generated waste water pollutants from
facilities that recycle waste water for use in processing,
is not to exceed the following limitations.
Effluent Effluent
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Characteristic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
Except as provided for in paragraph (1) , there is to be no
discharge of process generated waste water pollutants into
navigable waters.
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 limitations set forth below are based on the use of the best
practicable control technology currently available.
Effluent Limitation
kq/kkg
Effluent (lb/1000 Ib) of product
Characteristic Monthly Average Daily Maximum
TSS 0.023 0.046
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 recommended.
Mine dewatering discharges are not to exceed the following
limitations.
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Effluent Effluent
Character!stic Limitations
Maximum for Average of daily
any one day values for thirty
consecutive days is
not to exceed
TSS 45 mg/1 25 mg/1
pH Within the range of 6.0 to 9.0.
GYPSUM (DRY)
The limitation which can be attained based on 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 limitation which can be attained based on 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.
GYPSUM (MINE DEWATERING)
Mine- dewatering discharge is not to exceed 30 mg/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 limitation which can be attained based on 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 limitation which can be attained based on 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
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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 limitation which can be attained based on 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 limitation which can be attained based on 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 limitation which can be attained based on 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 discharge is not to exceed 30 mg/1 TSS.
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.
WOLLASTONITE
The limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants
because no process water is used. Mine dewatering is not to
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.
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LIGHTWEIGHT AGGREGATE MINERALS (PERLITE)
The limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants
because no process water is used. Mine dewatering is not to
exceeds0 mg/1 TSS. 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 limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants
because no process water is used. Mine dewatering is not to
exceed 30 mg/1 TSS. 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 limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants. This
technology (alternative A) involves 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 is not to exceed
30 mg/1 TSS. 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 limitation which can be attained based on 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 limitation which can be attained based on 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 subcategory (2059) utilizes the recommended
technologies. Another (2055) recycles part of the process
waste water.
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MICA (WET BENEFICIATION PROCESS, EITHER NON-CLAY OR
GENERAL PURPOSE CLAY BY-PRODUCT)
The limitation which can be attained based on the best prac-
ticable 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 BENEFICIATION PROCESS, CERAMIC GRADE CLAY BY-PRODUCT)
The limitation set forth below is based on the use of the
best practicable control technology currently available.
Effluent Limitation
kg/kkg of product (lb/1000 Ib)
Effluent Characteristic Monthly Average Daily Maximum
TSS 1.5 3.0
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 is not to exceed 30 mg/1 TSS. 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 SUBCATEGORY
The limitation which can be attained based on 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 limitation which can be attained based on 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 is not to exceed 30 mg/1 TSS. Four
facilities in these subcategories in the same net
precipitation geographical location are currently achieving
this limitation.
BARITE (MINE DEWATERING)
Non-acidic mine dewatering is not to 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 limitation which can be attained based on 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).
FLUORSPAR (FLOTATION)
The limitation set forth below are based on the use of the
best practicable control technology currently available.
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Effluent. Limitation
kg/kkg of product (lbs/1000 Ibl
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.6 1.2
dissolved fluoride 0.2 0.4
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 limitation which can be attained based on 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 discharge is not to exceed 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 limitation which can be attained based on the best
practicable control technology currently available is no net
discharge of process waste water pollutants. These
operations return the depleted 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 limitation which can be attained based on the best
practicable control technology currently available is no net
discharge of process waste water pollutants. The only
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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 limitation which can be attained based on 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.
BORAX
The limitation which can be attained based on 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 limitation which can be attained based on 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 limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process waste water and mine dewatering
pollutants. This technology (alternative B) 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 (BRINE WELL)
The limitation which can be attained based on 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.
U2H
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ROCK SALT
The limitation set forth below is based on the use of the
best practicable control technology currently available.
Effluent Limitation
kg/kkq of product
(lb/1000 Ib)
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.02 0.04
The above limitation is based on the performance currently
achieved by at least three facilities. Mine dewatering is
included in the above limitation. 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 techniques would require better
water management practices and the installation of adequate
settling facilities where required.
PHOSPHATE ROCK
The limitation set forth below is based on the use of the
best practicable control technology currently available.
Effluent Limitation
Effluent Monthly Average Daily Maximum
Characteristic
TSS 30 mg/1 60 mg/1
The above limitation is 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, age of treatment facility and activity.
This last point is demonstrated by the fact that volatile
suspended solids comprised the majority of the TSS of the
final effluents. Many plants experience high rates of algae
growth in their settling ponds because of the nature of the
intake water, or for other reasons such as the presence of
425
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nitrogen in the waste water (e.g. ammonia is used as a
processing reagent). To prevent contamination of intake
water, some facilities might have to switch sources of
process water (from surface water to ground water). This
change could cause additional environmental problems. 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 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 are not 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
treatment 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 guidelines were based are presently achieving
the recommended limitations using these technologies. All
426
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Western operations do or will shortly recycle all such
waters.
SULFUR (FRASCH PROCESS, ANHYDRITE)
The limitation which can be attained based on 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.
SULFUR (FRASCH PROCESS, SALT DOME OPERATIONS)
The limitations set forth below are based on the use of the
best practicable control technology currently available.
Effluent Limitation
Effluent mg/1
Characteristjc Monthly Average Daily Maximum
TSS 50 100
sulfide 1 2
The above limitations are based on the current performance
(alternative C, D, 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
mcr/1
Effluent Monthly Daily
Characteristic 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
427
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recommended technologies. Well seal water is not regulated
at this time.
SULFUR (FRASCH PROCESS - OFF-SHORE SALT DOME OPERATIONS)
No limits on off-shore operations are recommended 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 limitation which can be attained based on 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 is not to exceed 30 mg/1 TSS based on the
data from other subcategories.
LITHIUM MINERALS (SPODUMENE)
The limitation which can be attained based on 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 4009 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 are
not to 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 is not to exceed 35 mg/1 TSS. 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 fuller1s earth.
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BENTONITE
The limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants,
because no process water is used. Mine dewatering is not to
exceed 35 mg/1 TSS. 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' earth 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 limitation which can be attained based on 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 is not to exceed 35 mg/1 TSS. 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 fuller's
earth. Acid mine drainage must meet the following
limitations:
Effluent Characteristic
Monthly Average Daily Maximum
TSS, mgl 35 70
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 limitation which can be attained based on 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,
3088 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 is not to
429
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exceed 35 mg/1. The data in Section VII indicates that this
can be achieved by current practice.
FULLER'S EARTH (MONTMORILLONITE)
The limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants. Two
facilities studied (3059r3073)presently use the recommended
technology. Mine dewatering is not to exceed 35 mg/1 TSS.
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 CDRY PROCESSING)
The limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants. This
is feasible since no process water is used.
KAOLIN (WET PROCESSING)
The limitations set forth below are based on the use of the
best practicable control technology currently available.
Effluent Limitation
Effluent Characteristic Monthly Average Daily Maximum
TSS, mg/1 45 90
Turbidity, JTU 6r FTD 50 100
Zinc, mg/1 0.25 0.50
The above limitations were based on a statistical analysis
of the performance attainable by two facilities (3024 and
3025). In 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 is not to exceed 35 mg/1 TSS.
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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 H5 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 limitation which can be attained based on 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.
BALL CLAY (DRY PROCESSING)
Where ball clay is processed without the use of wet
scrubbers for air emissions control there is no need to
discharge process waste water since it is either evaporated
or goes to the product. Hence, the limitation which can be
attained based on best practicable control technology
currently available is no discharge of process generated
waste water pollutants.
BALL CLAY (MINE DEWATERING)
Mine dewatering is not to exceed 35 mg/1 TSS.. The data in
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)
The limitations set forth below are based on the use of the
best practicable control technology currently available.
Effluent Limitation
kq/kkg (lb/1000 Ib) of ore processed
Effluent Characteristic Monthly Average Daily Maximum
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TSS 0.60 1.2
Fluoride 0.175 0.35
The above limitations were based on the performance achieved
by three exemplary facilities for TSS (3026, 3054 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 40 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 limitation which can be obtained based on 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 is not to exceed 30 mg/1 TSS. Feldspar
mining is a hard rock operation and the suspended solids
appear to settle rapidly as in crushed stone operations.
Mine runoff rather than dewatering is the normal method of
water escape.
KYANITE
The limitation which can be attained based on 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 is not to exceed
35 mg/1 TSS. Mine dewatering was not practiced at the mines
inspected.
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MAGNESITE
The limitation which can be attained based on 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 limitation which can be attained based on the best
practicable control technology currently available is no
discharge of process generated waste water pollutants, since
no water is used. Mine dewatering is not to exceed 35 mg/1
TSS. This technology involves settling or the use of
flocculants on an intermittent basis.
APLITE
The limitation which can be attained based on 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 is not
to exceed 35 mg/1 TSS. Mine dewatering was not practiced at
the mines inspected.
TALC, STEATITE, SOAPSTONE AND PYROPHYLLITE (DRY PROCESS)
The limitation which can be attained based on 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 limitation which can be attained based on 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)
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The limitation set forth below is based on the use of the
best practicable control technology currently available.
Effluent Limitation
kg/kkg (lb/1000 Ib) of product
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.5 1.0
The above limitation is based on the performance achieved by
three facilities (2032, 2033 and 204U) and a fourth facility
(2031) achieving no discharge of process waste water. This
technology (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, PYROPHYLLITE (MINE DEWATERING)
Mine dewatering is not to exceed 30 mg/1 TSS. This
limitation is based on the data from 8 mines given in
Section VII.
GARNET
The limitations set forth below is based on the use of the
best practicable control technology currently available.
Effluent Limitation
Effluent Characteristic 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 limitation which can be attained based on 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 quantity 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 techniques can be
employed.
13H
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Mine dewatering is not to exceed 30 mg/1 TSS. 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 (5504, 5505 and
5500) of this subcategory representing approximately half
the U.S. production utilize this recommended technology.
Mine dewatering is not to exceed 30 mg/1 TSS. 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 limitations set forth below are based on the use of the
best practicable control technology currently available.
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 limitation which can be attained based on 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.
435
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NOVACULITE
The limitation which can be attained based on 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.
436
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SECTION X
EFFLUENT REDUCTION ATTAINABLE THROUGH THE
APPLICATION OF THE BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE
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;
(4) process changes;
(5) the cost o£ 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
include the following;
(1) alternative water uses
(2) water conservation
(3) waste stream segregation
(4) 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.
437
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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 attainable limitations for mine dewatering waste water
discharges are the same as for the best practicable control
technology currently available. The pH 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 25-
year 24 hour precipitation event (as established by the
National Climatic Center, National Oceanic and Atmospheric
Administration for the locality in which such impoundments
are located) to 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 required to
achieve no discharge of process generated waste water
pollutants to navigable waters based on the application of
the best practicable control technology currently available,
dimension stone
crushed stone (dry)
construction sand and gravel (dry)
industrial sand (dry)
gypsum
bituminous limestone
oil impregnated diatomite
gilsonite
asbestos
wollastonite
438
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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.
The best available technology economically achievable is the
same as the best practicable control technology currently
available for the following subcategories,hence the same
limitations are proposed:
crushed stone (wet)
crushed stone (flotation process)
crushed stone (mine dewatering)
construction sand and gravel (wet)
construction sand and gravel (mine dewatering)
construction sand gravel (dredging with land processing
industrial sand (wet process)
industrial sand (acid and alkali flotation process)
Mica (wet beneficiation process, ceramic grade clay by-product)
barite-wet (log washing, jigging and flotation)
fluorspar (flotation)
439
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salines from brine lakes
phosphate rock.
lithium minerals (spodumene)
kaolin (wet processing)
garnet
graphite
mica (wet beneficiation process, ceramic grade clay by-produc
barite-wet (log washing, jigging and flotation)
fluorspar (flotation)
salines from brine lakes
phosphate rock
lithium minerals (spodumene)
kaolin (wet processing)
garnet
graphite
INDUSTRIAL SAND (HF FLOTATION)
The limitation which can be attained based on 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.
ROCK SALT
The limitations set forth below are based on the use of the
best available technology economically achievable.
Effluent Limitation
kq/kkg of product
(lbs/1000 Ib)
Effluent Characteristic Monthly Average Daily Maximum
TSS 0.002 0.004
(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
440
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covering less frequently used piles with plastic or other
fabric.
SULFUR (PRASCH PROCESS, SALT DOME OPERATIONS)
The limitations set forth below and based on the use of the
best available technology economically achievable.
Effluent Limitation
Effluent mq/1
Characteristic Monthly Average Daily Maximum
TSS 30 60
sulfide 1 2
The above limitations are based on the current performance
of 5 of the 9 facilities. 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 both bleed water and seal water for this
subcategory is included in the above limitations. The
practiced technology is improved settling to reduce
suspended solids and aeration to eliminate sulfides. 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.
The best available technology for operations located in
marshes that have limited land available to build large
oxidation ponds to achieve the above limitations, the
following limitations shall apply.
Effluent Limitation
Effluent mq/1
Characteristic Monthly Average Daily Maximum
TSS 30 60
sulfide 2 4
SULFUR (FRASCH PROCESS— OFF SHORE SALT DOME OPERATIONS)
No limitations are proposed at this time pending further
investigation.
-------
FELDSPAR (FLOTATION)
The limitations set forth below are based on the use of the
best available technology economically achievable.
Effluent Limitation
Effluent kg/kkg (lb/1000 lb| ore processed
Characteristic Monthly Average Daily Maximum
TSS 0.6 1.2
Fluoride 0.13 0.26
The above limitation for fluoride is based on an improvement
in exemplary facility performance by lime treatment to
reduce fluorides to 30 mg/1 in the HF contaminated
segregated waste water. The limitation on suspended solids
for best practicable control technology currently available
is deemed also to represent 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 equipment or ponds.
TALC MINERALS GROUP (HEAVY MEDIA AND FLOTATION)
The limitation set forth below is based on the use of the
best available technology economically achievable.
Effluent Limitation
Effluent kg/kkq (lb/1000 Ib) of product
Characteristic Monthly Average Daily Maximum
TSS 0.3 0.6
The above limitation was based on the performance of one
facility (2032) plus one facility achieving no discharge of
process water (2031)i The best available technology
economically achievable for the processing of talc minerals
by the heavy media 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.
442
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SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
AND PRETREATMENT STANDARDS
Limitations based on this level of technology are to be
achieved by new sources. The term "new source" is defined
in the Act to mean "any source, the construction of which is
commenced after the publication of proposed regulations
prescribing a standard of performance." This technology is
evaluated by adding to the consideration underlying the
identification of 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 25-
year 24 hour . precipitation event (as established by the
National Climatic Center, National Oceanic and Atmospheric
Administration for the locality in which such impoundments
are located) to 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.
Based on the best practicable control technology currently
available, attainable limits for the following industry
subcategories were no discharge of process generated waste
water pollutants to navigable waters.
dimension stone
crushed stone (dry)
crushed stone (flotation)
construction sand and gravel (dry)
construction sand and gravel (land processing)
industrial sand (dry)
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
444
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sodium sulfate
sulfur (anhydrite)
mineral pigments
bentonite
fire clay
fuller1s earth (montmorillonite and attapulgite)
kaolin (dry process)
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 new source performance standard should be the same as the
limitations based on the application of the best practicable
control technology.
INDUSTRIAL SAND (HF flotation Process)
The industrial sand (HF flotation process) subcategory was
required to achieve no discharge of process generated waste
water pollutants to navigable waters based on best available
technology economically achievable. The same limitations
are recommended as the new source performance standard.
The new source performance standards for the subcategories
listed below are to be the same as the limitations based on
the best available technology economically achievable.
crushed stone (wet)
crushed stone (mine dewatering)
construction sand and gravel (wet)
construction sand and gravel (mine dewatering)
construction sand and gravel (dredging with land processing)
industrial sand (wet process)
mica (wet beneficiation process, ceramic grade clay by-product)
barite (wet and flotation)
salines from brine lakes
fluorspar (floatation)
phosphate rock
rock salt
sulfur (Frasch process - salt dome)
lithium minerals (spodumene)
kaolin (wet process)
feldspar (flotation)
talc group (heavy media and flotation process)
HUS
-------
garnet
graphite
SULFUR (FRASCH PROCESS-OFF SHORE SALT DOME OPERATIONS
No limitations are reconunended at this time pending further
investigation.
PRETREATMENT STANDARDS
tf 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 thats
has a flow of 50,000 gallons or more per average work day;
has a flow greater than five percent of the flow carried by
the municipal system receiving the waste; has in its waste,
a toxic pollutant in toxic amounts as defined in standards
issued under Section 307 (a) of the Act; or is found by the
permit issuance authority, in connection with the issuance
of an NPDES permit to the publicly owned treatment works
receiving the waste, to have significant impact, either
singly or in combination with other contributing industries,
on that treatment works or upon the quality of effluent from
that treatment works.
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:
446
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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
fuch wastes;
c. Solid or viscous wastes in amounts which would cause
obstruction to the flow in sewers, or other interference
with the proper operation of the publicly owned
treatment works, and
d. Wastes at a flow rate and/or pollutant discharge rate
which is excessive over relatively short time periods so
that there is a treatment process upset and subsequent
loss of treatment efficiency.
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
carbon, phosphorus and phosphorus compounds, nitrogen
and nitrogen compounds, and fats, oils, and greases,
need not be removed provided the publicly owned
treatment works was designed to treat such pollutants
and will accept them. Otherwise levels should be at 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.
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SECTION XII
ACKNOWLEDGEMENTS
The preparation of this report was accomplished through the
efforts of the staff of General Technologies Division,
Versar, Inc., Springfield, Virginia, under the overall
direction of Dr. Robert G. Shaver, Vice President. Mr.
Robert C. Smith, Jr., Chief Engineer, Project Office,
directed the day-to-day work on the program.
Mr. Michael W. Kosakowski and Mr. Ron Kirby were the EPA
Project Officers. Mr. Robert B. Schaffer, Director,
Effluent Guidelines Division, and Mr. William A. Telliard,
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 Kaye Starr
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
449
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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 gave us invaluable assistance and
cooperation in this program.
Also, our appreciation is extended to the individuals of the
staff of General Technologies Division of Versar, Inc., for
their assistance during this program. Specifically, our
thanks to:
Dr. R. L. Durfee, Senior Chemical Engineer
Mr. D. H. Sargent, Senior Chemical Engineer
Mr. E. F. Abrams, Chief Engineer
Mr. L. C. McCandless, Senior Chemical Engineer
Dr. L. C. Parker, Senior Chemical Engineer
Mr. E. F. Rissman, Environmental Scientist
Mr. J. C. Walker, Chemical Engineer
Mrs. G. Contos, Chemical Engineer
Mr. M. W. Slimak, Environmental Scientist
Dr. I. Frankel, Chemical Engineer
Mr. M. DeFries, Chemical Engineer
Ms. C. V. Fong, Chemist
Mrs. D. K. Guinan, Chemist
Mr. J. G. Casana, Environmental Engineer
Mr. R. C. Green, Environmental Scientist
Mr. R. S. Wetzel, Environmental Engineer
Ms. M.A. Connole, Biological Scientist
Ms. M. Smith, Analytical Chemist
Mr. M. C. Calhoun, Field Engineer
Mr. D. McNeese, Field Engineer
Mr. E. Hoban, Field Engineer
Mr. P. Nowacek, Field Engineer
Mr. B. Ryan, Field Engineer
Mr. R. Freed, Field Engineer
Mr. N. O. Johnson, Consultant
Mr. F. Shay, Consultant
Dr. L. W. Ross, Chemical Engineer
Mr. J. Boyer, Chemical Engineer
450
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SECTION XIII
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451
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452
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40. "Product Directory of the Refractories Industry in the
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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.
454
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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 synonum for bench.
Blunge - to mix thoroughly.
Cell, cleaner - secondary cells for the pretreatment 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 hydrophobia.
Conditioner - an apparatus in which the surfaces of the
mineral species present in a pulp are treated with
455
-------
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 annular space between
the outer chamber and cone being tapered.
Crusher, gyratory - a primary crusher consisting of a
vertical spindle, the foot of which is mounted in an
eccentric bearing within a conical shell. The top
carries a conical crushing head revolving eccentrically
in a conical maw.
Crusher, jaw - a primary crusher designed to reduce the size
of materials by impact or crushing between a fixed plate
and an oscillating plate or between two oscillating
plates, forming a tapered jaw.
Crusher, roll - a reduction crusher consisting of a heavy
frame on which two rolls are mounted; the rolls are
driven so that they rotate toward one another. Rock is
fed in from above and nipped between the moving rolls,
crushed, and discharged below.
Depressant - a chemical which causes substances to sink
through a froth, in froth flotation.
Dispersant - a substance (as a polyphosphate) for promoting
the formation and stabilization of a disperson of one
substance in another.
Dragline - a type of excavating equipment which employs a
rope-hung bucket to dig up and collect the material.
Dredge, bucket - a two-pontooned dredge from which are
suspended buckets which excavate material at the bottom
of the pond and deposit it in concentrating devices on
the dredge decks.
Dredge, suction - a centrifugal pump mounted on a barge.
Drill, churn - a drilling rig utilizing a blunt-edged chisel
bit suspended from a cable for putting down vertical
holes in exploration and quarry blasting.
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.
456
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Drill, rotary - various types of drill machines that rotate
a rigid, tubular string of rods to which is attached a
bit for cutting rock to produce boreholes.
Dryer, flash - an appliance in which the moist material is
fed into a column of upward-flowing hot gases with
moisture removal being virtually instantaneous.
Dryer, fluidized bed - a cool dryer which depends on a mass
of particles being fluidized by passing a stream of hot
air through it. As a result of the fluidization,
intense turbulence is created in the mass 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, whereas other minerals
sink.
Frother - substances used in flotation to make air bubbles
sufficiently permanent, principally by reducing surface
tension.
Grizzly - a device for the coarse screening or scalping of
bulk materials.
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.
457
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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 quartz pebbles, porcelain balls,
etc.
Mill, buhr - a stone disk mill, with an upper horizontal
disk rotating above a fixed lower one.
Mill, chaser - a cylindrical steel tank lined with wooden
rollers revolving 15-30 times a minute.
458
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Mill, hammer - an impact mill consisting of a rotore fitted
with movable hammers„ that is revolved rapidly in a
vertical plane within a closely fitting steel casing.
Mill, pebble - horizontally mounted cylindrical mill,
charged with flints or selected lumps of ore or rock.
Mill, rod - a mill for fine grinding, somewhat similar to a
ball mill, but employing long steel rods instead Of
balls to effect the grinding.
Mill, roller - a fine grinding mill having vertical rollers
running in a circular enclosure with a stone or iron
base.
Neutralization - making neutral or inert, as by the addition
of an alkali or an acid solution.
Outcrop - the part of a rock formation that appears at the
surface of the ground or deposits that are so near to
the surface as to be found easily by digging.
Overburden - material of any nature, consolidated or
unconsolidated, that overlies a deposit of useful
materials, ores, etc.
Permeability - capacity for transmitting a fluid.
Raise - an inclined opening driven upward from a level to
connect with the level above or to explore the ground
for a limited distance above one level.
Reserve - known ore bodies that may be worked at some future
time.
Ripper - a tractor accessory used to loosen compacted soils
and soft rocks for scraper loading.
Room and Pillar - a system of mining in which the
distinguishing feature is the winning of 50 percent or
more of the ore in the first working. The ore is mined
in rooms separated by narrow ribs {pillars); the ore in
the pillars is won by subsequent working in which the
roof is caved in successive blocks.
Scraper - a tractor-driven surface vehicle the bottom of
which is fitted with a cutting blade which when lowered
is dragged through the soil.
Scrubber, dust - special apparatus used to remove dust from
air by washing.
459
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Scrubber, ore - device in which coarse and sticky ore .is
washed free of adherent material, or mildly
disintegrated.
Shuttle-car - a vehicle which transports raw materials from
loading machines in trackless areas of a mine to the
main transportation system.
SIC - Standard Industrial Classification (code)
Sink-float - processes that separate particles of different
sizes or composition on the basis of 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 conveyer 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
460
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Thickener - an apparatus for reducing the proportion of
water in a pulp.
TSS - Total Suspended Solids
Waste - the barren rock in a mine or the part of the ore
deposit that is too low in grade to be of economic value
at the time.
Weir - an obstruction placed across a stream for the purpose
of channeling the water through a notch or an opening in
the weir itself.
Wire saw - a saw consisting of one- and three-strand wire
cables, running over pulleys as a belt. When fed by a
slurry of ~-*nf ter and held against rock by
tension, it :hannel by abrasion.
461
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TABLE 48
en
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
ac
acft
BTU
BTU/lb
cfm
cfe
cuft
cu ft
cu in
Fo
ft
gal
gpm
hp
in
inHg
Ib
mgd
mi
pslg
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 cal
kg cal/kg
cu m/min
cu m/min
cu m
1
cu cm
°C
m
1
I/see
kw
cm
atm
kg
cu m/day
km
atm
sq m
sq cm
kkg
m ,
hectares
cubic meters
kilogram - calories
kilogram calories/kilogran
cubic meters/minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
killowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres (absolute)
square meters
square centimeters
metric tons (1000 kilograr
meters
'Actual conversion/ not a multiplier
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