EPA-600/2-76-138
May 1976
Environmental Protection Technology Series
COAL PREPARATION ENVIRONMENTAL
ENGINEERING MANUAL
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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RESEARCH REPORT8NG SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental
Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the
views and policy of the Agency, nor does mention of trade
names or commercial products constitute endorsement or
recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-76-138
May 1976
COAL PREPARATION
ENVIRONMENTAL ENGINEERING
MANUAL
by
David C. Nunenkamp
J.J. Davis Associates
7900 Westpark Drive
McLean, Virginia 22101
Contract No. 68-02-1834
Program Element No. EHE623
EPA Project Officer: Mark J. Stutsman
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ACKNOWLEDGMENTS
The author wishes to express his sincere thanks and
appreciation for the support and assistance received from
the many people contacted during the development of this
manual.
Special appreciation for Mr. T. Kelly Janes and Mr.
Mark J. Stutsman of the Environmental Protection Agency's
Control System Laboratories, Clean Fuel Division at the
Research Triangle Park, North Carolina for their patience
and guidance as Technical Project Officers and to
Mr. M. P. Huneycutt and Mr. Fisher A. Fair of the Research
Triangle Park's Contract Management Division for the work
as contract administrators.
In addition, the author wishes to express sincere
thanks to Mr. Daniel R. Walton of J. J. Davis Associates,
Inc. for his contribution of Chapters 9 and 10 on the
storage and transportation of the clean coal and refuse
products and to Mr. James P. Connell, Manager, Mining
Engineering, W. A. Wahler & Associates for the detailed
discussion and graphics of solid coal waste disposal con-
tained within Chapter 13. Their contributions are not
only important, but are in fact an integral part of this
document.
And lastly, the author wishes to thank Mr. Stanley P.
Jacobsen of the U. S. Bureau of Mines' Coal Preparation
and Analysis Group of Bruceton, Pennsylvania, for his
diligent efforts and excellent commentary while serving
as a third party technical editor, without whose efforts
many of the thoughts and concepts discussed in this manual
would not have been brought to their full conclusions.
ii
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TABLE OF CONTENTS
COAL PREPARATION ENVIRONMENTAL
ENGINEERING MANUAL
CHAPTER PAGE
1 INTRODUCTION !
1.1 Background 1
1.2 Purpose 5
1.3 Organization 5
2 THE NATURE OF COAL 9
2.1 Coal and Its Origin . 9
2.2 Properties of Coal 15
2.2.1 Specific Gravity 17
2.2.2 Size Stability and Uniformity 18
2.2.2.1 Friability 19
2.2.2.2 Weathering 19
2.2.3 Grindability 20
2.2.4 Impurities in Coal 21
2.2.4.1 Moisture 21
2.2.4.2 Minerals 22
2.2.4.2.1 Clay and Shale 24
2.2.4.2.2 Sulfur 26
2.3 Coal Reserves 28
3 • OBJECTIVES OF COAL PREPARATION 41
3.1 Background ' 41
3.2 Current Practice 42
3.3 Metallurgical Coke 44
iii
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
OBJECTIVES OF COAL PREPARATION (Continued)
3.4 Steam Coal 45
3.5 Summary 48
4 THE PREPARATION PROCESS 53
4.1 Overview 53
4.2 Preparation Plant Modules 60
•5 PLANT FEED PREPARATION AND RAW COAL STORAGE 69
5.1 Overview 69
5.2 Initial Size Check -69
5.2.1 Fixed ROM Coal Screen 72
5.2.2 Vibrating ROM Coal Screen 72
5.3 Initial Size Reduction 75
5.3.1 Rotary Breaker 78
5.3.2 Other ROM Coal Crushers 80
5.4 Raw Coal Storage 83
5.4.1 Open Storage for Raw Coal 86
5.4.2 Closed Storage for Raw Coal 88
5.4.2.1 Steel Storage Bins 88
5.4.2.2 Concrete Silos 89
6 RAW COAL SIZING 95
6.1 Overview 95
6.2 Notes on Screening 97
6.3 Application 1°7
6.3.1 The Raw Coal Screen 1°7
6.3.2 Pre-Wetting Screens 109
7 RAW COAL SEPARATION 115
7.1 Overview
7.2 Specific Gravity Separation
IV
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TABLE OF CONTENTS
(Continued)
CHAPTER . PAGE
RAW COAL SEPARATION (Continued)
7.3 Methodologies 121
7.3.1 Dense Medium Separation of Coarse Coal 121
7.3.1.1 Magnetite Dense Media Coal 124
Cleaning
7.3.1.2 Sand Cone Dense Media Coal 136
Cleaning
7.3.2 Dense Media Coarse Size Coal Washing 141
Equipment
7.3.3 Hydraulic Separation of Coarse Coal 152
7.3.4 Hydraulic Coarse Coal Cleaning Equipment 161
7.3.5 Separation of Intermediate Size Coal 170
7.3.5.1 Dense Media Cyclones '171
7.3.5.2 Hydrocyclones 176
7.3.5.3 Wet Concentrating Tables 181
7.3.5.4 Fine Coal Launders and Jigs 181
7.3.6 Separation of Fine Size Coal 190
8 PRODUCT DEWATERING AND DRYING 209
8.1 Overview 209
8.2 Methodology 210
8.2.1 Natural Drainage 210
8.2.2 Screens 212
8.2.2.1 Special Purpose Screens for 216
the Heaving Media Process
8.2.2.2 Special Purpose Combination 221
Screens (Intermediate and Fine)
8.2.2.3 Special Purpose Solid Recovery 222
Screens
8.2.2.4 Special Purpose Fixed Screens 227
8.2.3 Centrifugal Dewatering 233
8.2.4 Filtration 242
v
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
PRODUCT DEWATERING AND DRYING (Continued)
8.2.5 Thermal Drying 249
8.3 Thickening Coal and Refuse Slurries 255
8.3.1 Hydraulic Cyclones 257
8.3.2 Classifiers 260
9 CLEAN COAL STORAGE AND HANDLING 275
9.1 Overview 275
9.2 Clean Coal Sotrage 278
9.2.1 Open Storage for Clean Coal 280
9.2.2 Closed Storage for Clean Coal 285
9.3 Clean Coal Handling 287
9.3.1 Unit Train Loading 288
9.3.2 Barge Loading 293
9.3.3 Slurry Pipeline 297
10 REFUSE HANDLING 301
10.1 Overview 301
10.2 Materials Handling 302
10.2.1 Refuse Handling by Aerial Tramway 303
10.2.2 Refuse Handling by Belt Conveyor 303
10.2.3 Vehicular .Haulage Units 305
11 THE COMPLETE PREPARATION PLANT 313
11.1 Overview 313
11.2 The Complete Plant 314
11.2.1 The Coarse Size Coal Circuit 316
11.2.2 The Intermediate Size Coal Cleaning Circuit 320
11.2.3 The Fine Size Coal Cleaning Circuit 323
11.2.4 The Refuse Recovery Circuit 327
11.2.5 Process Quantities 329
11,3 The Economics and Management of Coal Preparation 331
VI
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
THE COMPLETE PREPARATION PLANT (Continued)
11.3.1 Defining Properties of Raw Coal 335
11.3.2 Washability Studies 338
11.3.3 Determining Economical Washing 339
Specific Gravities
11.3.4 Selection of the Process Flowsheet 342
12 POTENTIAL POLLUTANTS 349
12.1 Introduction 349
12.2 Identification of Potential Pollutants 350
12.2.1 Solid Refuse 350
12.2.2 Mine Site and Waste Dump Drainage 356
12.2.3 Air Contaminants 364
12.2.3.1 Aerosols or Particulate 365
Matter
12.2.3.2 Inorganic Gases 368
12.2.4 Noise 371
13 . CONTROL OF POTENTIAL POLLUTANTS 391
13.1 Introduction 391
13.2 Refuse Disposal and Pollution Control 391
Technology
13.2.1 Refuse Disposal Versus Constructed 398
Embankments
13.2.2 Refuse Disposal Site Selection Criteria 404
13.2.2.1 Hydrologic Investigations 407
13.2.2.1.1 Seepage and Pore 413
Pressure
13.2.2.2 Stability Analysis 419
13.2.2.3 Physical Properties of Coarse 420
Coal Refuse
13.2.2.3.1 Grain Size 421
Distribution
VII
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
CONTROL OF POTENTIAL POLLUTANTS (Continued)
13.2.2.3.2 Atterberg Limits 427
13.2.2.3.3 Specific Gravity 427
13.2.2.3.4 Natural Water Content 427
and Dry Density
13.2.2.3.5 Compaction Character- 429
istics
13.2.2.3.6 Permeability 432
13.2.2.3.7 Compressiblity 434
13.2.2.3.8 Shear Strength 434
13.2.2.4 Physical Properties of Fine Coal 437
Refuse
13.2.2.4.1 Grain Size Distri- 438
bution
13.2.2.4.2 Plasticity Charac- 438
teristics
13.2.2.4.3 Specific Gravity 438
13.2.2.4.4 Natural Water Content 438
and Dry Density
13.2.2.4.5 Compaction 441
13.2.2.4.6 Permeability 444
13.2.2.4.7 Compressibility 445
13.2.2.4.8 Shear Strength 446
13.2.2.5 Conclusions Regarding Physical 449
Properties of Coal Refuse Materials
13.2.2.5.1 Unique Characteristics 451
of Coal Refuse
13.2.2.5.2 Conveyance and Placement 452
13.2.3 Types of Refuse Deposits 454
13.2.3.1 Ridge Dump* .454
, 13.2.3.2 Side-Hill Dump 456
13.2.3.3 Cross-Valley Dump 456
viii
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
CONTROL OF POTENTIAL POLLUTANTS (Continued)
13.2.3.4 Valley Fill Dump 457
13.2.3.5 Waste Heap 457
13.2.3.6 Complex Dump 457
13.2.4 Construction Techniques Proposed for 458
Consideration
13.2.4.1 Modification of Existing Deposits 459
13.2.4.1.1 Active Deposits 459
13.2.4.1.2 Inactive Deposits 460
13.2.4.1.3 Abandoned Deposits 460
13.2.4.2 Proposed Deposits 461
13.2.5 Types of Refuse Impoundments 462
13.2.5.1 Cross-Valley Impoundments 463
13.2.5.2 Side-Hill Impoundments 465
.13.2.5.3 Diked Pond 465
13.2.5.4 Incised Pond 466
13.2.6 Construction Techniques 466
13.2.7 Surveillance, Maintenance and Abandonment 471
13.2.7.1 Surveillance 473
13.2.7.2 Embankment Surveillance and 476
Instrumentation
13.2..7.2.1 Surface Monuments 477
13.2.7.2.2 Piezometers 478
13.2.7.2.3 Internal Movement 479
Devices
13.2.7.3 Maintenance 48°
13.2.7.4 Abandonment 481
13.2.8 Embankment Construction Inspection 483
13.2.8.1 Requirements of Plans and 485
Specifications
13i,2.8.2 Verifications of Design Assumptions 485
IX
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
CONTROL OF POTENTIAL POLLUTANTS (Continued)
13.2.8.3 Site Inspector's Functions 486
13.2.8.4 Regulatory Agency 488
13.2.8.4.1 If Method Specifications 490
are Used
13.2.8.4.2 If Performance Specifi- 491
. cations are Used
13.2.8.5 Documentation of Inspection Control 492
Results
13.2.9 Embankment and Impoundment Recognition 493
Summary
13.2.9.1 Conditions Affecting Stability 493
13.2.9.1.1 Loading Area 494
13.2.9.1.2 Toe Area 494
13.2.9.1.3 Materials Area 495
13.2.9.1.4 Foundation Area 496
13.2.9.2 Forms of Instability 497
13.2.9.2.1 Rotational Slips 497
13.2.9.2.2 Surface Slips 497
13.2.9.2.3 Flow-Type Slides 497
13.2.9.2.4 Creep 498
13.2.4.2.5 Back-Sapping 498
13.2.9.3 Factors Affecting Stability 499
13.2.9.3.1 Appearance of the Site 500
13.2.9.3.2 General Embankment 501
Characteristics
. 13.2.9.3.3 Slude Disposal 502
Considerations
13.2.9.3.4 Water as It Relates to 502
Embankment Stability
13.2.9.3.5 Water as It Relates to 503
Flooding
13.2.9.4 Hazards Rating System 504
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
CONTROL OF POTENTIAL POLLUTANTS (Continued)
13.2.10 Control of Mine Drainage from Coal* 507
Refuse Deposits
13.2.11 Closed Water Circuit 613
13.2.11.1 Thickeners and/or Clarifiers 514
13.2.11.2 Impoundment 518
13.2.11.3 Underground Stowage 519
13.2.11.4 Mechanical Dewatering 519
13.2.11.5 Thermal Drying or Self-Incineration 524
13.2.11.6 Chemical Additives 526
13.2.12 Preparation Plant Process Water 527
13.2.13 Coal Waste Disposal Summary 532
13.3 Air Pollution Control , 532
13.3.1 Summary of Proposed Air Quality Standards 534
13.3.1.1 Selection of Pollutants for Control 535
13.3.2 Applying Dust Collection Equipment 536
to the Coal Cleaning Process
13.3.2.1 Exhaust Hoods 539
1303.2.2 Ducts 540
I3a3i,203 Mechanical Collection 54^
Equipment
13.3.3 Specific Applications to the 547
Thermal Drying Process
13.4 Noise Pollution Control 548
13.4.1 Reduction of Preparation 'Plant Noises 553
13.4.2 Control of Plant Noises Intrusion Into 557
Nearby Communities
14 REMOVAL OF CONTAMINANTS FROM COAL 575
14.1 Overview 575
XI
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TABLE OF CONTENTS
(Continued)
CHAPTER PAGE
REMOVAL OF CONTAMINANTS FROM COAL (Continued)
. ,14.2 Washability Studies 580
: 14.2.1 Description of Testing Procedures 582
(Float and Sink Analysis)
14.2.2 Description of Testing Procedures 586
(Total Sulfur and Form of Sulfur)
14.3 Washability Data 592
APPENDICIES 627
Appendix I Glossary of Selected Terms 628
Appendix II Coal-Waste Disposal Inventory Questionnaire 653
Appendix III Washability Curves and the Interpretation 665
of Float-and-Sink Data
Appendix IV Performance Criteria 673
Appendix V Calculation and Plotting of Distribution 679
Curves
Appendix VI Predicting Cleaning Results Using 685
Distribution Curve Data
Appendix VII List of Applicable ASTM Standards 691
Appendix VIII Buying Directory 693
Appendix IX English Metric Conversion Charts 725
Xll
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LIST OF FIGURES !
FIGURE PAGE
1-1 U.S. Supplies and Uses of Coal (Million Tons) 2
Ir2 U.S. Soft Coal Productivity by Mine Type 3
2-1 Some of the Features Affecting the Continuity of 11
Coals
2-2 .Faults 12
2-3 A Clay Vein Interrupting the Coal and Overlying 13
Strata
2-4 Igneous Intrusion 14
2-5 The Coal Fields of the United States 29
2-6 The Coal Fields of the United States 32
3-1 By-Product Coke Oven 45
4-1 The Modern Preparation Plant 55
4-2 Preparation Plant Modules 64
5-1 Plant Feed Module Highlighted 70
5-2 Rotary Breaker 73
5-3 Bar Screens of "Grizzly" 74
5-4 Vibrating ROM Coal Screens 76
5-5 ROM "Bradford" Breaker in a Well-Controlled 79
Environment
5-6 Roll Crusher in Worst Possible 79
Environment
5-7 Cross-Section of Double-Roll Crusher 81
5-8 Crushing Heads 81
5-9 Open Raw and Clean Coal Storage 84
5-10 Enclosed Raw and Clean Coal Storage 84
5-11 Conical Pile and Dead Storage 87
5-12 Conical Pile With Earth Fill to Eliminate Dead 87
Storage
5-13 Details of a Concrete Silo 90
6-1 Product Sizing Module Highlighted 96
6-2 Illustration of Screen Use 98
xiii
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LIST OF FIGURES
(Continued)
FIGURE
6-3 Representation of Screening Action in the
Logitudinal Direction
6-4 Standard Type of Perforated Screen
6-5 Common Types of Profile Rod Screens
6-6 Typical Double-Deck Inclined Vibrating Screen
6-7 Pre-Wet Screening Operation
7-1 • Product Separation Module Highlighted
7-2 Misplaced Material in the Separation Products
7-3 Distribution Curve of Raw Coal to Clean Coal;
Coarse Versus Fine Coal Fractions
7-4 Examples of Coal Cleaning Equipment
7-5 Simplified Typical Dense-Medium Coarse Coal
Washer Flowsheet
7-6 Dense Media Separating Vessel
7-7 Mechanical Coal Removing System
7-8 Middling Product Removal System
7-9 Refuse Removal System
7-10 , Drain and Rinse Screens
7-11 Dense and Dilute Media Sump and Pump
7-12 Magnetite Recovery Unit
7-13 Recovery of Magnetite from Spent Media
7-14 Makeup Water Head Tank
7-15 ' Magnetite Feed and Density Control System
7-16 Magnetite Recovery Circuit
7-17 The Dense Media Chance "Sand Cone"
7-18 McNally Tromp Dense Media Vessel
7-19 , McNally Tromp Three-Product Vessel
7-20 , McNally Lo-Flo Vessel
7-21 DMS Dense Media Coal Washer
7-22 Link-Belt Tank-Type Heavy Media Coal Washer
7-23 Barvoy Heavy Media Vessel
PAGE
101
103
104
105
110
116
118
119
122
127
128
129
129
130
' 130
131
132
132
133
133
135
139
143
144
146
146
148
149
xiv
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LIST OF FIGURES
(Continued)
FIGURE PAGE
7-24 DSM Shallow Bath Vessel 150
7-25 H&P Heavy Media Wash Box 151
7-26 Simulated Results of Stratification Process in 153
a Coal Washing Jig
7-27 Typical Baum-Type Jig 155
7-28 Various Stages in the Stratification Process 158
7-29 McNally Norton Standard Washer I62
7-30 McNally Mogul Washer 163
7-31 McNally Mogul Washer as Observed in a Preparation 164
Plant
7-32 McNally Giant Washer I65
7-33 Baum Jig Cross-Section 166
7-34 Side View Cross-section of Batac Jig 167
7-35 Batac Jig Cross-Section 169
7-36 A Dense Media Cyclone and the Idealized Flow I"72
Pattern Within
7-37 Typical Dense Media Cyclone Circuit 177
7-38 Hydrocyclone Cross-Section and Flow Diagram 179
7-39 Typical Deister Table Installations 184
7-40 Rubber Riffles on a Concentrating Table 185
7-41 A Fully Loaded Table in Good Adjustment 185
7-42 The Distribution of Table Products by Particle 187
Size and Specific Gravity
7-43 Contributing Equipment to the Fine Coal Circuit ' 191
7-44 The Flotation Concept 193
7-45 Coal Laden Froth 194
7-46 Typical Multi-cell Froth Flotation Installation 194
7-47 Floatability as a Function of Particle Size 195
8-1 Product Dewatering Module Highlighted 211
8-2 Natural Drainage Via a Bucket Elevator 213
8-3 Typical Vibrating Screen Installation 213
xv
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LIST OF FIGURES
(Continued)
FIGURE PAGE
8-4 Screens Used in a Typical Heavy Media System 219
8-5 Solid Recovery Screen Applications 224
8-6 Running the Screen Product Uphill 225
8-7 Sieve Bend 228
8-8 Schematic Diagram of a Sieve Bend 229
8-9 Vor-Siv 231
8-10 Centrifugal Force Diagram 234
8-11 Bird Solid Bowl Centrifuge 236
8-12 Perforate Basket Centrifuge 238
8-13 Horizontal Vibrating Basket Centrifuge 240
8-14 Vertical Vibrating Basket Centrifuge 241
8-15 Operational Diagram of a Coal Vacuum Filter 243
8-16 Individual Filter Compartments 244
8-17 Standard Vacuum Filter Installation 244
8*18 Rotary Drum Coal Filter 246
8-19 Filtration Rate Versus Feed Solids 247
8-20 Schematic Diagram of a Typical Fine Coal 249
Filter Circuit
8-21 Typical Thermal Coal Dryer 252
8-22 The Thermal Dryer 256
8-23 Obvious Air Pollution Problems When Unchecked 256
8-24 Hydraulic Cone ; 256
8-25 Typical Hydraulic Cyclone Installation . 262
8-26 A Working Screw Classifier 262
9-1 Storage and Shipping Module Highlighted 276
9-2 Conical Shaped Stockpile 281
9-3 Wedge Shaped Stockpile 283
9-4 Kidney Shaped Stockpile 284
9-5 Steel and Concrete Storage Silos 285
9-6 Monolithic Concrete Bin 286
xvi
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LIST OF FIGURES
(Continued)
FIGURE PAGE
9-7 Flood Loading From Steel Surge Bin 287
9-8 Two-Silo Unit Train Loading System
9-9 Minimal Unit Train Loading Facility
9-10 Maximized Unit Train Loading Facility
9-11 Car Haul System of Unit Train Loading
9-12 Unit Train Loading With Moveable Tripper 292
9-13 Unit Train Being Loaded Out in a Western Mine 294
9-14 Barge Loading with Moveable Tripper
9-15 Various Barge-Loading Facilities
10-1 Continuous Aerial Tramway 304
10-2 Three-roll Idler Conveyor Belt System 305
10-3 Combination Conveyor and Truck Refuse Handling 307
System
11-1 Flowchart for a Complete Preparation Plant 315
11-2 Flowchart for Coarse Size Coal Circuit 317
11-3 Highlights of the Drain and Rinse Process in 317
the Coarse Coal Circuit
11-4 Flowchart for Intermediate Size Coal Circuit 321
11-5 Flowchart for Fine Size Coal Circuit 325
11-6 Refuse Recovery Circuit 328
11-7 Product Quantities 332
11-8 Sensitivity Analysis for Metallurgical Coal 333
11-9 Sensitivity Analysis for Steam Coal 334
11-10 Typical Washability Curves 340
11-11 Determination of Economical Washing Specific 341
Gravities
12-1 Typical Disposal Sites - 358
12-3 Potential Fugitive Emission Sources 366
13-1 "Dump" Disposal Site 401
13-2 Planned Refuse Site 401
xvii
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LIST OF FIGURES
(Continued)
FIGURE PAGE
13-3 Refuse Disposal System Development Flow Chart 405
13-4 Refuse Disposal System Development Flow Chart 406
13-5 Coefficient of Permeability (ft/day) 407
13-6 Gradation Summary, Coarse Coal Refuse 422
13-7 Gradation Summary, Coarse Coal Refuse 424
13-8 Gradation Summary, Coarse Coal Refuse 425
13-9 Gradation Summary, Fresh Coarse Coal Refuse 426
13-10 Atterberg Limits, Coarse Coal Refuse 428
13-11 Natural Moisture Content, Coarse Coal Refuse 430
13-12 In-Place Dry Density, Coarse Coal Refuse 431
13-13 Compressibility Charts, Coarse Coal Refuse 435
13-14 Shear Strength Parameters, Coarse Coal Refuse 436
13-15 Gradation Summary, Fine Coal Refuse 439
13-16 Natural Moisture Content, Fine Coal Refuse 440
13-17 In-Place Dry Density, Fine Coal Refuse 442
13-18 Compaction Charts, Fine-Grained Coal Refuse 443
13-19 Compressibility Charts, Fine Coal Refuse 447
13-20 Shear Strength Parameters, Fine Coal Refuse 448
13-21 Simple Dump Forms 455
13-22 Simple Impoundment Forms 464
13-23 Basic Stability and Hazard Diagram 494
13-24 Thickener Tank Designs 515
13-25 Standard Tunnel Solids Withdrawal System 516
13-26 Impact of Polymer on Solids Recovery 523
13-27 Plant Refuse Removal and Some Optional Methods 533
of Disposal
13-28 A Packed-Bed Scrubber 545
13-29 Typical Impingment Scrubber Design 546
13-30 Venturi Scrubber Shown as Part of a Complete 549
Coal Dryer
xviii
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LIST OF FIGURES
(Continued)
FIGURE
13-31 Maximum Daily Noise Exposure Permitted
By MESA
14-1 Estimated Costs of Sulfur Removal Potential 578
of Different Emission Control Strategies
14-2 Flow Diagram Showing Preparation of Face 584
Samples
14-3 Nomograph Relating Sulfur Content and
Calorific Value in COals to Pounds of SO
Emission Per Million Btu
14-4 The Effect of Crushing to 1 1/2 inch, 3/8 inch
and 14 Mesh Top Size on the Reduction of Ash,
Pyritic Sulfur, Total Sulfur and Pounds S0_
Emission per Million Btu at Various Specific
Gravities of Separation for All U.S. Coals
14-5 Percent of All U.S. Coal Samples Meeting the 615
Current EPA Standard of 1.2 Pounds SO /MM Btu
with no Preparation, Curve a; Compared with
Those Crushed to 1 1/2 inch Top Size at a Btu
Recovery of 90 Percent, Curve b; and Those
Crushed to 14 mesh Top Size at a Btu Recovery
of 50 Percent, Curve c, and Separated
Gravimetrically
xix
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LIST OF TABLES
TABLE PAGE
2-1 Classification of Coals by Rauls 16
2-2 Grindability Indexes of Some American Coals 20
2-3 Minor and Trace Elements in Coal 23
4-1 Preparation Plant Capital and Operating Costs 56
4-2 Comparative Coal Costs for Utility Consumption 61-62
Utilizing Cleaned Coal and Run-of-Mine Coal From
The Same Mine
5-1 Sizes and Capacities of Rotary Breakers 80
5-2 Capacities and Double-Roll Crushers 82
8-1 TPH Capacity of Vibrating Screens 217
Dewatering Presized Coal at 1/4"
8-2 TPH Capacity of Vibrating Screens Dewatering 217
Coarse Presized Coal at 1/2 mm
8-3 TPH Capacity of Vibrating Screens Dewatering 217
Fine Coal at 1/4 mm
8-4 TPH Capacity of Vibrating Screens Dewatering 218
Fine Coal at 1/2 mm
8-5 TPH Capacity of Vibrating Screens Dewatering 218
Fine Coal at 1 mm
8-6 TPH Capacity of Single Deck Low-Head Media 221
Recovery Screens at 1/2 mm
8-7 TPH Capacity of Combination Sizing, Dewatering 222
and Desliming Screens Handling 3/8" x O or
1/4" x O coal
8-8 TPH Capacity of Solids Recovery Screens Receiving 226
Only Fine Coal Feed 1 mm or 1/2 mm x O
8-9 TPH Capacity of Solid Recovery Screens Receiving 226
1/4" x o Coal + Thickened Fine Coal Slurry
8-10 36 Inch Diameter Positive Discharging Perforate 287
Basket Centrifuging Performance
8-11 Typical Performance Data for Vertical Vibrating 239
Basket Centrifuges
8-12 Pressure Versus Disc Filter 245
8-13 Typical Performance of a 14 Inch Diameter 261
Hydraulic Cyclone
xx
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LIST OF TABLES
(Continued)
PAGE
Percent of Coal Samples Meeting EPA Standards 314
of 112 lbs/SC-2 Per m Btu
11-2 Process Quantities for a Typical 1,000 tph 330
Coal Cleaning Plant
11-3 Impact of Near-Gravity Material on the 342
Separation Process
12-1 . Specific Gravity Results for Fine Coal Refuse 351
12-2 Distribution of Particle Sizes in Samples of 354
Underground-Mine Refuse
12-3 Selected Chemical Characterists of Samples 355
of Underground-Mine Refuse
12-4 Criteria for Determining Acid Mine Drainage 351
12-5 Particulate Emission Factors for Thermal Coal 368
Dryer
12-6 Trace Metal Analysis of Particulate Emissions 359
From a Coal Dryer
12-7 Rank Ordering of Equipment in Terms of Noise 372
Source
12-8 Typical Major Equipment List in a Large Processing 375
Plant and Associated Noise Level dB(A)
13-1 Specific Gravity Results for Coarse Coal Refuse 427
13-2 Compaction Characteristics—Coarse Coal Refuse 432
13-3 Specific Gravity Results for Fine Coal Refuse 441
13-4 Possible Consequences of Embankment Failure 505
13-5 Pressure Filter Use Versus Disc Filter Use 520
13-6 Combustion Product Emissions From Well-Controlled 535
Thermal Dryers
•13-7 Fugitive Emissions from Coal Preparation Plants 539
13-8 Permissible Noise Exposures Prescribed by the Walsh-Healy Act
14_1 Summary of the Physical Desulfurization 5gi
Potential of Coals by Region
XXI
-------
LIST OF TABLES
(Continued)
TABLE PAGE
14-2 Typical Washability Data Plus Interpolated 594
Values Provided by U.S. Bureau of Mines
14-3 Screen Analyses of Upper Kittanning - Bed Coal 595
14-4 Chemical and Physical Properties of upper 595
Kittanning - Bed Coal
14-5 Detailed Washability Analysis of Upper 597-600
Kittanning-Bed Coal Showing the Effecto of
Crushing on the Liberation of Pyritic Sulfur
(1 1/2 Inch Top Size)
14-6 Detailed Washability Anaysis of Upper 601-603
Kittanning-Bed Coal Showing the Effect of
Crushing on the Liberation of Pyritic Sulfur
(3/8 Inch Top Size)
14-7 Sample Washability Data From U.S. Bureau 606-607
of Mines RI 8118
14-8 Detailed Washability Data Lower 608
Kittanning-Bed Coal
14-9 Detailed Washability Data Lower 610
Kittanning-Bed Coal
14-10 Detailed Washability Data Lower 611
Kittanning-Bed Coal
xxn
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I. INTRODUCTION
1.1 BACKGROUND
The oil embargo and the sudden awareness of the United
States to the cost of our current dependence upon foreign
energy sources has set this country forth on a project to
obtain energy self-sufficiency by the early 1980's. As a
direct result, the United States requirements for coal in
1985 may be as much as 1.7 billion tons per year. With the
annual production of coal in the early 1970's running
between 575 million to 600 million tons per year, this
estimate indicates that the U. S. production of coal must
triple in about 15 years. More conservative estimates,
some of which were made before the energy crisis and oil
embargo of 1973-74, indicated that the United States
requirements would be about one billion tons per year in
the early 1980's. The published goals for President Ford's
Project Independence (our country's plan to achieve energy
self-sufficiency by 1985) include a requirement for 1.2
billion tons of coal to be produced annually by 1985.
The mere setting of this goal to double or triple coal
production over a 10 year period is not sufficient. A
concerted effort by the entire country, including consumers,
producers, and governmental agencies, must be made in order
to obtain these goals. The projected demands which may be
placed upon the coal industry come at a time when coal
production, and, specifically, productivity have encountered
-------
many setbacks. Coal production in recent years has been
considerably below the projected 1985 demands. In fact
the total tonnage of mechanically cleaned coal in this
country was actually decreasing until 1972, e.g., 335
million tons in 1969 to 271 million tons in 1971. In 1972,
the total tonnage of mechanically cleaned coal increased
for the first time since 1967 to a total of 289 million
tons. Figure 1-1 delineates the U.S. coal production and
related consumption in the period 1950-1974.
U.S. SUPPLIES AND USES OF
COAL
(MILLION TONS)
USES
DOMESTIC PRODUCTION OF BITUMINOUS.
ANTHRACITE. AND LIGNITE
TONS
(MILLIONS)
600
500
400
300
200
100
TRANSPORTATION
HOUSEHOLD
AND
COMMERCIAL
1950
56 58
60 62 64
YEAR
19%
1950 CURRENT
ELECTRICITY
GENERATION
(UTILITIES)
Figure 1-1
U.S. Supplies and Uses of Coal (Million Tons)
While U.S. production of coal fluctuated between 400
and 600 million tons annually since 1950, the productivity
(production per man shift) enjoyed a nearly uninterrupted
rate of increase. This increase in productivity in all
types of mines held true until the enactment of the Coal
2
-------
Mine Health and Safety Act of 1969 which appears to have
reduced the productivity of underground coal mining. Strip
mining has continued to enjoy increases in productivity,
however. Figure 1-2 shows the productivity of U.S. coal
mines from 1910 to 1974.
50
40
TONS/MAN 30
SHIFT
20
10
AUGER
SURFACE
i- UNDERGROUND
1910
'20
60 '70 1980
Figure 1-2
U.S. Soft Coal Productivity by Mine Type
Assuming that the industry is unable to make dramatic
improvements in productivity in existing mines and that
600 million additional tons of coal annually are required
by 1985, then 70% of the projected 1.2 billion annual
tonnage must come from mines not now in existence.
Specifically, enough new mines must be opened to produce
an additional 600 million tons of coal annually over the
next decade, in addition to mines needed to replace those
that are being closed as they are worked out. According
to Dr. John Fallon, then Director of the Federal Energy
Administration, April 7,.1975, in a speech given to the
Institute of Electrical and Electronics Engineers, the
following action will be necessary to achieve the 1985
production levels:
-------
. . Develop 140 new 2 million ton per year Eastern
underground mines,
develop 30 new 2 million ton per year Eastern
surface mines,
develop 100 new 5 million ton per year Western
surface mines,
recruit and train 80 thousand new Eastern coal
miners and
recruit and train 45 thousand new Western coal
miners.
This plan of action is ambitious to say the least.
Disregarding the long-term problems confronting the coal
industry, the short-run obstacles alone are considerable.
To open a new coal mine takes many years lead time; normally
eighteen months are required to develop a new surface mine,
and five to nine years are required to develop a new
underground mine. To achieve an increase in coal production
of 600 million tons per year by 1985 will require that, on
the average, one new underground mine (2 million tons/yr.)
and one new surface mine (5 million tons/yr.) be brought
into production every month for the next ten years. In
contrast, only 13 mines with capacity greater than 2 million
tons per year were brought into production during the
decade of the 1960's.
It is certainly feasible for the industry to open the
new mines and produce the extraction equipment required.
Assuming it can also solve the manpower requirements, the
next step toward increased coal production is coal benefac-
tion equipment and the facilities in which the coal is
cleaned. It will be necessary to design and construct as
many coal preparation plants as new coal mines. The old
philosophy that one need only extract the coal from the
ground and allow the consumer (primarily electric utilities)
-------
to worry about the processing arid consumption of the coal
is being altered rapidly.
With the current emphasis on coal utilization and with
the mounting concerns over the waste disposal practices of
the coal mining industry, it is imperative that individuals
involved with the coal production industry, and specifically
those involved with the monitoring of this industry, have
a basic understanding of the processes and techniques of the
physical cleaning of coal, the known potential pollutants,
and the current practices for control of these pollutants.
1.2 PURPOSE
The purpose of this manual is to provide an introduction
to and assessment of the physical cleaning of coal together
with its environmental impact. Specifically, this manual
covers the general characteristics of the coals found in the
United States, provides an overview of the coal preparation
plant, discusses the major equipment and processes currently
utilized in the physical cleaning of coal, identifies the
primary wastes produced during the coal cleaning operation,
and discusses the techniques of control currently applied to
those wastes. The information contained will provide an
overview of the state-of-the-art of the physical cleaning
of coal, together with an understanding of the environmental
issues and concerns which need to be addressed.
1.3 ORGANIZATION
The manual is organized in such a way that it will
allow the reader to absorb the material he needs without
having to read the entire work. The nature of coal, its
origin, some of its basic properties and the objectives of
physical coal cleaning are discussed in Chapters 2 and 3.
A generalized discussion of the coal preparation
operation, the coal cleaning plant, process modules and
-------
process flow sheets are provided in Chapter 4. Chapters 5
through 10 address the major activities within the coal
preparation plant as defined in Chapter 4.
Chapter 11 reviews the coal preparation plant in total,
providing insight into the quantities of coal, refuse and
transporting media in each of the generalized areas
discussed in Chapters 5 through 10. In addition, the
subject of relative cost for the cleaning of coals of
different sizes at different levels is addressed to assist
the reader in developing or analyzing the cost/benefit
relationship of coal beneficiation.
Chapters 12 and 13 discuss the known waste streams
emanating from the coal cleaning operation as they originate
within the preparation plant and the current practice of
minimizing and controlling those waste streams.
-------
REFERENCES AND/OR ADDITIONAL READING
Bailey, Ralph E., "Coal Industry Overview", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania May 1975
National Coal Association, "Bituminous Coal Facts - 1970"
National Coal Association, "Coal Makes the Difference", 56th National
Coal Association Convention, June 1973
Resource Planning Associates, Inc., "Energy Supply/Demand Alternatives
for the Appalachian Region—Executive Summary", Council for Environ-
mental Quality, Appalachian Regional Commission and the National
Science Foundation, Report EQ-022, March 1975
U.S. Bureau of Mines, "Bituminous Coal and Lignite Shipments from
Coal Producing District by Ranges of Sulfur Content (Calendar Year
1970)", Division of Fossil Fuels, 1973
W.A. Wahler & Associates, "Analysis of Coal Refuse Dam Failure—
Volume I", National Technical Information Service, Springfield,
Virginia, February 1973
Williams, Cyril H., Jr., "Planning, Financing and Installing a New
Deep Mine in the Beckley Coal Bed", Mining Congress Journal,
August 1974
Yancik, Joseph H., "Research to Improve Coal Mining Productivity",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Zitting, Richard T., "Solid Fuels: Their Contribution to Energy
Independence", American Mining Congress Convention, October 1974
-------
THIS PAGE INTENTIONALLY LEFT BLANK
-------
2. THE NATURE OF COAL
2.1 COAL AND ITS ORIGIN
Coal may be defined as a combustible material formed
from accumulations of plant material: trees, (including—
roots, trunks, bark, leaves), bushes, ferns, pollen and
spores. During the time most coal was formed, the air was
very humid. Many of the plants were huge ferns and trees
which died and were replaced time after time for thousands
of years. The growing accumulations of the dead and dying
material in a swamp or bog gradually became rotten soggy
masses commonly referred to as peat.
During the Pennsylvanian Age, 300 million years ago,
the great peat swamps of North America extended over
enormous areas along wide coastal plains. These swamps
provided sufficiently wet conditions to permit exclusion of
air from much of the vegetable materials before decay could
begin and the rapid accumulation of the materials thwarted
bacterial action. In addition, acidity of swamp water
normally prevented bacterial action at a few inches or a
few feet below the water level. As the peat accumulated,
the weight of the top layers compacted the lower layers by
squeezing out large amounts of water.
After a while, large areas of the earth's surface sank
and streams and oceans invaded the swamps carrying salt
water, clay mud and sand. The salt water killed the
remaining plants and the peat accumulations were buried
-------
beneath tons of clay and sand. The burial of the peat by
the sediment accompanied by the physical and chemical
effects associated with the changed environment and by the
loss of water and volatile matter resulted in a change of
color and appearance of the peat; the peat became lignite,
which is the lowest ranked coal.
Successive invasions of the sea and the piling of
layer upon layer of sedimentary material resulted in the
deep burial of the lignite deposits. Deep burial resulted
in a rise in temperature, and the additional pressure
squeezed out more of the retained swamp gases and moisture.
These activities contributed to the process of
"coalification" or the completion of the metamorphosis of
'the plant debris and the formation of bituminous coal.
In some geographic areas and under special circumstances,
still another step occurred in the coalification process.
The layers of coal, together with the underlying and
overlying strata, were subjected to awesome compressive
forces as the great plates of the earth's crust moved and
pushed against each other forming mountainous folds. This
wrinkling of the crust produced high temperatures, and the
coal, thus heated and compressed, changed again; this time
the resulting product is called anthracite.
Many geological factors influence thickness, continuity,
quality and mining conditions of coal. Some geological
features occurred during peat accumulation or shortly
thereafter, others occurred millions of years later. The
.recognition of the nature of these features is important
in the mining operation and ultimately affects the physical
cleaning of the coal. Several of the more common features
that affect coal cleaning are described below.
10
-------
xxxxxxxxxxxxxx xxxxxxxxxxxxx xxxxxxxxx
Glociol drift
Modtrnvolbylin
Gray inol*
Sotfitoni
Unwtlm
Bleat ifcoM
CM
Swffock
Figure 2-1
Some of the Features Affecting the Continuity of Coals
Coal removed by modern stream erosion at A; preglacial
erosions at B; by a stream after coal deposition at C;
and at D, the stream was present throughout the time
of peat accumulation.
Shale partings—streams periodically flood the
peat swamps where the vegetable material accum-
ulates, depositing mud and silt layers that
become bands of slate and siltstone after the
vegetable material is coalified. In general,
the closer the peat beds were to the flooding
stream, the thicker the deposits left and the
more total was the disruption to the bed.
Washouts—after the plant material has been
accumulated and buried by various sediments, it
may be removed by the erosive actions of streams.
This activity is called a washout. Washouts
may occur shortly after deposition of the peat
or after coalification is complete.
Faults—Faults are fractures in the rock sequence
along which the strata on each side of the
fracture appear to have moved in different
directions. The movement may be measured from
inches to miles and in any direction from
horizontal to vertical. Two of the most common
types of faults observed are illustrated below.
11
-------
Where stresses are in opposite directions,
rocks have been pulled apart at the fracture
surface and displacement is as illustrated
for a "normal fault". Where horizontal
compressive forces are responsible for fault-
ing, one block may be shoved over the other
producing a "thrust" or "reverse fault".
Figure 2-2
Faults
With Normal Fault (A) strata above fault have moved down
to those above; with Reverse Fault (B) strata above have
moved up.
Clay veins—irregular, vertical to inclined
tabular masses of clastic material (clay, sand
or silt) that interrupt the coal seam are called
clastic dikes or "clay veins" (see Figure 2-3).
These clay veins may be from a fraction of an
inch to several feet thick and may extend for
some distance into the strata overlying the coal.
They frequently contribute to roof instability
as the coal is mined. The clay veins tend to be
numerous in some areas and commonly intersect
each other. They add to the waste material that
must be removed from the salable coal as well
as creating safety hazards and drainage problems.
Concretions—the coal as well as the associated
rocks commonly contains aggregations of minerals
in spherical, disc-like or irregular forms. They
may be microscopic or several feet across,
although the most commonly observed size is
several inches wide. Mine and roof shales
12
-------
commonly contain concretions made up of Calcite
(CaCo3), Dolomite (CaMg(C03)2), Siderite (FeC03)
and Pyrite (FeS2). The presence of large concre-
tions in mine roof material may have a considerable
effect upon roof stability creating safety hazards
and adding to the waste material. In the coal
headed for a preparation plant, pyritic concretions
are common, ranging from less than an inch to
several feet and are usually referred to as
sulfur balls.
xxxxxxxxxxxxxxxx
Figure 2-3
A Clay Vein Interrupting the Coal and Overlying Strata
13
-------
Igneous Intrusions—in some areas, the coal and
associated strata may have been intruded by once-
molten igneous rocks forcibly injected into the
sedimentary sequence from below. The igneous
rock is commonly seen as a dike which is a nearly
vertical tabular mass cutting across the bedding
of the sediments. Depending on the size of the
igneous mass and its temperature, the coal is
thermally affected, being either advanced in rank
or coked immediately adjacent to the igneous body,
The igneous rocks that occur within a coal seam
are much harder than the coal which may cause
mining problems and contribute to preparation
problems.
xxxxxxxxxx
xxxxxxx xxxx
XXXXXXXXX X/i
XXXXXXXXX
: x x x^x xxxxxxxxx
fx x x x^^^t x x x x x x x
x x x x x x)or x x x x x x
XXXXXXXX X X X X XXX
Figure 2-4
Igneous Intrusion
An igneous dike cuts through a coal bed and spreads
out into a sill at the top of the bed. A thin zone
adjacent to the igneous rock has been thermally
altered to natural coke.
14
-------
2.2 PROPERTIES OF COAL
The material we call coal is classified by a series of
chemical analyses and physical tests which define the coal
in its various stages of metamorphism. Coal increasingly
metamorphoses (responds to pressure and heat) from lignite
and subbituminous ranks through the high-volatile, medium-
volatile, low-volatile bituminous coal ranks to anthracite
and meta-anthracite. Coalification is a gradual process
and the classification of coal by ranks is just an
identification of the various stages of that process and is
based upon such properties as the percentage of fixed carbon,
the percentage of volatile matter, calorific value and the
agglomerating character as shown in Table 2.1. However, the
classification by ranks does little to describe the overall
complexities of the chemical and physical composition of
different coals.
Coal is a very complex material and its chemical
composition varies widely. The principle differences
between coals can be traced to the different plant
assemblages in the original forest, and to the history of
the coal bed since it was formed.
The original peat bogs and coastal swamps were
occasionally subjected to flooding by streams from adjacent
hills. As this happened additional clay and silt were
deposited in the swamp. These additional deposits became
mixed with the plant debris and are responsible for the ash
content of the coal: The muddier the original bog, the
greater the ash content of the coal. As the peat became
buried, other changes occurred. The deeper it was buried,
the greater the compression and heat experienced by the bed.
The greater the compression and heat, the more the volatile
constituents were removed: The more volatiles removed, the
greater the carbon content of the coal.
15
-------
rt
(D
CO
CD
hj
(D
o
i-h
H-
£
in
Class
Fixed Carbon
Limits, %
(Dry Mineral-
Matter-Free
Basis)
Volatile Mat-
ter Limits,
% (Dry, Min-
eral-Matter-
Free Basis)
Group
Equal
or
Greater Less
Than Than
Equal
or
Greater Less
Than Than
Calorific Value
Limits, Btu per
Lb (Moist,"
Mineral-Matter-
Free Basis)
Equal
or
Greater Less
Than Than
Agglomerating
Character
I. Anthracitie
II. Bituminous
III. Subbituminous
IV. Lignitic
1.
O
3.
1.
o
3.
4.
5.
1.
o
3.
1.
o
Meta-anthracite 98
Anthracite 92 98
Sciniaiithracite'' 86 92
Low-volatile bituminous 78 86
coal
Medium-volatile hitumi- 69 78
nous coal
High-volatile A bitu- . . 69
ruinous coal
High-volatile B bitu-
minous coal
High-volatile C bitu-
minous coal
Subbituminous A coal
Subbituminous S coal
Subbituminous C coal
Lignite A
Lignite B
.1
•2 8
8 14
14 22
22 31
31 .. 14,000"
13,000 <<
fll.SOU
\
110,500
10,500
9,500
8,300
6,300
. . 1
. . \- Nonagglomerating
• • J
Conimonlv ag-
14,000
13,000
11,500.
glomerating °
Agglomerating
11,500]
10,500
• r XoiiagElonierating
8,300 1
6,300,1
O
CO
H-
l-h
h1-
O
P
rt
p-
O
O
i-h
n
o
en
tr
I
01
tr
* From: American Society for Testing and Materials, D 388.
"This classification does not include a few coals, principally nonhanded varieties, which have unusual physical and chemical prop-
erties and which come within the limits of fixed carhon or calorific value of the high-volatile bituminous and subbituminous ranks. All
of these coals either contain less than 48% dry, mincral-matter-free fixed carbon or have more than 15,500 moist, mineral-matter-frco
Btu per Ib.
11 Moist n'fors to coal containing its natural inherent moisture but not including visible water on the surface of the coal.
c If agglomerating, classify in low-volatile group of the bituminous class.
''Coals having 69% or more fixed carbon on the dry, mineral-matter-free basis shall be classified according to fixed carbon, regard-
less of calorific value.
'It is recognized that there may be nonagglonierating varieties in these groups of the bituminous class, and there flre not a Mo
exceptions in high-volatiU' C bituminous group.
-------
In order to classify coal, we must be able to
recognize the different classes. This recognition ic
accomplished on the basis of identification of unique
characteristics. The characteristics which permit the
distinction between two specimens of coal are called
properties. The physical properties are concerned with the
characteristics of coal in its natural state, or prior to its
end use as a fuel. For example, the hardness of coal
determines the maintenance cost on coal handling equipment;
the specific gravity of coal determines the coal preparation
techniques used in a cleaning plant as well as the capacity
of coal bins, boats and size of cargo and other coal storage
facilities. The physical properties are, of course,
dependent upon the chemical constituents that make up coal.
The chief physical properties important to coal preparation
are:
Specific Gravity
Size Stability and Uniformity
Friability
Resistance to Weathering
Grindability
Presence of Impurities
The chemical constituents that are important to coal
preparation relate primarily to the impurities in the coal,
i.e., those that are not carbon such as moisture, ash,
pyrite, sulfur, etc.
2.2.1 Specific Gravity
The density of coal is its weight per unit of volume.
The specific gravity of coal is its density referred to the
density of water at 4°C. Various values ranging from 1.23
to 1.72 are recorded in literature for the specific gravity
17
-------
of "pure" coal. The variations are due to differences in
rank, differences in moisture and ash content and differences
in methods used to determine specific gravity. The specific
gravity of clean coal increases with rank and ranges from
lignite to anthracite. Coal of a given rank has a higher
apparent specific gravity when wet than when dry, and
similarly, a change in specific gravity is exhibited with the
change in ash content: Higher ash content gives higher
specific gravity. The most important use of this physical
characteristic is the part that it plays in the cleaning
of coal by wet cleaning methods. The basic principle on
which these operate is that the specific gravity of coals
differs from their associated impurities and that there is
a relationship between the velocity with which the particles
fall in water and their relative densities.
Shale, clay and sandstone, if pure, have a specific
gravity of about 2.6. Carbonaceous shale ranges in specific
gravity from 2.0 to 2.6 depending upon the quantity of
carbonaceous material present. Other impurities such as
gypsum, kaolin and calsite have specific gravities of
2.3o 2.6 and 2.7, respectively, while the specific gravity
of pyrite is about 5.0. Since the specific gravities of
all these impurities are considerably greater than the
specific gravity of coal, these impurities will fall to
the bottom of a container filled with water more rapidly
than coal. If the water is given a pulsating motion by
compressed air, for example, causing the water to move up
and down, the impurities will be kept at the bottom and
the coal at the top where it can be recovered.
2.2.2 Size Stability and Uniformity
Size stability and uniformity of a given coal are
critical to the coal cleaning operation because the cost of
cleaning the coal increases dramatically as the percentage
18
-------
of fine size coal in the preparation plant increases. The
size stability of coal may be expressed as a function of
friability and/or weathering.
2.2.2.1 Friability—The strength of coal is displayed,
among other ways, in its ability to withstand degradation
of size upon handling. The tendency towards breakage during
handling, termed "friability", depends to some extent on the
toughness, elasticity and fracture characteristics as well
as upon strength. The greater the friability of a given
coal, the greater the chance for size degradation, e.g.,
very friable coal will produce a larger percentage of fines
when the coal is fed to a crusher.
Friability normally increases with coal rank (with the
exception of anthracites) reaching a maximum in coals of
the low-volatile group. Coals of somewhat lower rank than
low-volatile are usually relatively non-friable and, hence,
resist degradation in size with its accompanying increase
in the amount of surface exposed to oxidation. With coals
of subbituminous rank, degradation by slacking or weathering
supplements that due to breakage or handling. Anthracites
are compared in friability to the subbituminous coals; both
are harder than bituminous coals and decidedly more
resistant to breakage than the very friable low-volatile
coals. Lignites were found to be the least friable of all
coals.
2.2.2.2 Weathering—Weathering is the tendency of
coals to disintegrate or slack on exposure to weather,
particularly when alternately wetted and dried or subjected
to hot sunshine. Lower ranked coals like lignite slack very
readily; subbituminous coals slack to some extent but less
readily than lignite; and bituminous coals are affected
only slightly by weathering. The size degradation caused
by slacking is expressed as a precentage and termed slack
19
-------
index. Slack indexes of five percent or less characterize
bituminous coals where as the slack indexes for lignite
approach 100 percent.
2.2.3 Grindability
Grindability of coal, or the ease with which it may
be pulverized, is a composite physical property embracing
other specific properties such as hardness, strength,
tenacity and fracture. A general relationship exists between
the grindability of a specific coal and its rank. Coals
that are the easiest to grind are found in the medium-
volatile and low-volatile groups. These coals are
decidedly easier to grind than coal of the high-volatile
bituminous, subbituminous and anthracite ranks. The most
common index of grindability is the Hardgrove grindability
index. Table 2-2 shows the varying grindability of some
Table 2-2
Grindability Indexes of Some American
Coals
Stale
Pennsylvania
Pennsylvania
Pennsylvania
Pennsylvania
West Virginia
West Virginia
West Virpinia
West Virginia
Virginia
Virginia
Virginia
Virginia
Illinois
Illinois
Illinois
Illinois
Kentucky
Kentucky -
Kentucky
Ohio
Ohio
Indiana
Alabama
Utah
Pennsylvania
County
Cambria
Indiana
Washington
Westmoreland
Fayclte
McDowell
Wyoming
Wyoming
Wise
Wise
Dickenson
Buchanan
Sangamon
Williamson
Fulton
Vcrmillion
Pike
Hell
Muhlenburg
Harrison
Belmont
Sullivan
Walker
Carbon
Schuylkill
Red
Lower Kittanning
Lower I-'reeport
Pittsburgh
Upper Freeport
Scwell
Pocahontas No. 3
Powclllon
No. 2 Gas
Morris
Tapgart
Upper Banner
Raven
No. (<
No. 6
No. 5
No. 7
F.lkhorn Nos. 1 & 2
Might Splint
No. 12
No. 8
No. 9
No. V
Black Creek
Castle Gate
Various
llurdgrovc
(Irindahilily
Imlfx
109
92
55
65
86
9ft
58
70
43
62
84
98
55
57
63
56
42
40
55
51
50
55
44
47
38
20
-------
United States coals. The capacity, power input for
pulverizing and repair costs of pulverizers vary with the
grindability index. The higher the index the easier the
coal is to grind.
2.2.4 Impurities in Coal
Coal is not a uniform substance, but rather a mixture
of combustible metamorphosed plant remains that vary in
both physical and chemical composition. The diversity of
the original plant materials and the degree of metamorphism
or coalification that have affected these materials are the
two major reasons for the variety of physical components in
coal. This widely varying composition greatly affects the
preparation characteristics of the coal.
2.2.4.1 Moisture--The percentage of moisture present
in a given coal bed commonly called "bed moisture", is more
or less constant throughout a given mine and is a general
characteristic of the rank of the coal. Bed moisture may
range from a low of 1, 2 or 3 percent in bituminous coal to
a high of 45 percent in lignite. The actual moisture
content of a given coal as it enters a preparation plant or
a steam generator is dependent upon a number of factors in
addition to its bed moisture. The mining methods used to
extract the coal, the storage techniques of both the raw
and the clean coal products, the method of cleaning and
drying of the coal and the method of transporting the coal
to user may all affect the moisture content of a coal.
The moisture in the coal, whether inherent or surface,
can be considered as an impurity from the viewpoint of
utilization. It is, of course, a dilutant in that it reduces
available energy yield of the coal in proportion to the
amount of moisture present and even in excess of this
amount for some uses, especially for coal's largest single
customer—. electric power generation. Not only does moisture
21
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replace potential energy in proportion to the amount present,
but it further robs Btu output because the moisture must be
heated to stack temperatures in the boiler furnace before
it is expelled.
2.2.4.2 Minerals—The mineral impurities occurring
in coal may be classified broadly into those that form ash
and those that contribute sulfur. From the standpoint of
coal cleaning, both the ash-forming and the sulfur-
containing impurities may be subdivided into two classes—
impurities that are structurally a part of the coal and
hence not separable by physical means, and inorganic
impurities that can be eliminated to a greater or lesser
extent by crushing and ordinary cleaning methods. The
relative rate at which the mineral and the organic materials
accumulated in the swamp determines the physical character
and ash content of the product that resulted. If organic
matter predominated, the product formed was coal containing
some inherited impurities. If silt predominated, a
carbonaceous shale was formed. Products intermittent
between these two are classified as bone or boney coal
depending upon the amount of silt incorporated in their
structure.
Coal ash varies greatly in its chemical composition.
It is a mixture of silica (SiC^) and alumina (A^C^) which
came from sand, clay, slate and shale; iron oxide (Fe2C>3)
from pyrite and marcasite; magnesia (MgO) and lime (CaO)
from limestone and gypsum; the alkalis, sodium oxide and
potassium oxide (Na20 and 1^0) ; phosphorus pentoxide (P2C>5) ;
and miscellaneous amounts of trace elements. Table 2-3
shows the important minor and trace elements found in most
coals. Much more detailed listings may be found in the
referenced literature. The residue from these minerals
after the coal has been burned is called ash. The average
22
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Table 2-3
Minor and Trace Elements in Coal
Minor Elements
(about 1% or more, on ash)
Trace Elements
(about 0.1% or less, on ash)
Pollutant;
Sulfur
Nitrogen
Ash-Forming:
Sodium
Potassium
Iron
Calcium
Magnesium
Silica
Alumina
Titanium
Named as Hazardous:
Beryllium
Fluorine
Arsenic-
Selenium
Cadmium
Mercury
Lead
Others Analyzed:
Coal Basis Ash Basis
Boron
Vanadium
Chromium
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Tin
Yttrium
Lanthanum
Uranium
Lithium
Scandium
Manganese
Strontium
Zirconium
Barium
Ytterbium
Bismuth
23
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ash content of the entire thickness of a coal bed is at
least 2 or 3% even for very pure coals, and 10% and more
for coals found in most commercial mines. Coal material
that is too high in ash for ordinary use may be called
bone coal, bituminous shale or black slate.
Some ash-forming impurities are so finely divided and
so intimately mixed with pure coal substances that they may
be considered a structural part of the coal. Impurities
of this type cannot be separated from the coal by physical
preparation. The chief value of determining them quantita-
tively is that they fix a minimum ash content of the cleanest
portion of the raw coal--the so-called true, fixed, normal
or inherent ash content. In the washing processes for
eliminating impurities, the value of inherent ash may be
approached as a limiting minimum to designate the portion
of the ash content of coal that is structurally part of the
coal itself and, therefore, cannot be separated by mechanical
means. Other impurities are interbedded with coal and may
be in thin layers or in thick rock-like deposits. Clay is
the most common substance in banded impurities consisting
mainly of one or more of the three common clay minerals--
kaolinite, illite and montmorillinite.
2.2.4.2.1 Clay and Shale One of the principal
contaminants of raw coal is clay or shale from the roof
and floor or from interbedded partings. Clay presents
major problems to the coal preparation plant. Approximately
95% of the coal cleaned in this country is cleaned using some
type of wet processing. The majority of these wet process
techniques use the difference in density between coal and
its associated impurities as the basis for separating the
coal from the impurities.
The pronounced tendency of clays to disintegrate in
water and to form plastic masses have definite implications
24
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in terms of the design and operation of preparation plants,
i.e., they show up as an additional capital cost in plant
design and as an operational cost on a daily basis. The
direct operational difficulties (cost) associated with the
particle disintegration and the resulting dispersion of
colloidal matter appear in the form:
of contamination to and increased viscosity of
dense-medium suspensions,
difficulties in dewatering and drying of the fine
coal sizes,
difficulties in the filtration of froth-flotation
products and
handling difficulties in the disposal of fine
refuse.
In addition to the items listed above and with specific
reference to the low-ranked lignite and subbituminous coals,
other operational difficulties arise when the lattice
structure of the particular clays associated with these
coals render them susceptible to swelling. These clays may
swell to such a degree that their apparent specific gravity
is altered significantly. This alteration brings the
specific gravity of the clay down to 1.60, very close to that
of the coal itself. As the specific gravity of the clays
approaches that of the coal being washed, several things may
happen. First, the clay becomes extremely difficult to
separate from the coal. Secondly, the apparent density of
the wash-bath is altered significantly allowing slate to be
discharged with the coal at the top of the washer.
(Specifics of the washing operation are addressed in
Chapter 7.)
The problems generated by clay and shales in a washing
plant appear to be related to the rank of the coal. In
anthracite coal, the shale is so well indurated and
25
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compacted that it is called slate and it shows very little
tendency toward particle disintegration. On the other hand,
clay and shale in low-rank coals, such as subbituminous,
.exhibit a maximum amount of particle disintegration and an
amplification of the difficulties discussed.
2.2.4.2.2 Sulfur—Of the minerals found in coal, sulfur
is the most important single element impeding the
utilization of coal as a clean fuel. Many U.S. steam coals
contain high percentages of sulfur which must be reduced as
air pollution regulations become increasingly more stringent.
The reduction of sulfur in coal is a difficult problem
which has long been under study.
Sulfur in coal is reported in detailed chemical
analysis as s.ulfate sulfur, pyritic sulfur and organic
sulfur. The sulfur content of coals varies from 0.1 to
10.0% by weight.
Sulfate sulfur, or that part of the total sulfur that
can be extracted by treatment with hydrochloric acid, is
usually of only minor importance (less than 0.1 weight
percent). The sulfate sulfur occurs in combination with
either calcium or iron and is usually water-soluble,
originating from in situ pyrite oxidation. The amount of
sulfate sulfur in a coal increases rapidly with weathering
as the oxidation of iron sulfides gives rise to ferrous
and ferric sulfates.
The term pyritic (sulfide) sulfur is used to refer to
either of the two dimorphous forms of ferrous disulfide
(FeS2)--pyrite or marcasite. The two minerals have the
same chemical composition, but have different crystalline
forms. Pyrite is isometric (cubic) and marcasite is
orthorhombic. The Victorian brown coals of Australia are
an exception in that marcasite is virtually the only
sulfide material reported.
26
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Microscopic pyrites occur predominantly in coal in
four forms:
1. Veins—generally thin and film-like along the
vertical joints (cleat), but may be up to several
inches wide and contain large pyrite crystals with
well developed crystal faces.
2. Lenses—extremely variable in shape and size but
generally flattened and elongated in cross sections,
ranging in size from a fraction of an inch thick
to several inches in diameter.
3. Nodules or balls—roughly spherical in shape and
from inches to several feet in diameter. These
sulfur balls are usually not pure pyrite but
include one or more of the following—calcite,
siderite, clay minerals and organic matter.
4. Pyritized plant tissue—often included with the
carbonate minerals in a "coal ball", which is a
portion of coal in which the plant material has
undergone replacement by inorganic material
rather than coalification.
Sulfide sulfur occurs as individual particles (0.1
micron to 25 cm. in diameter) disseminated throughout all
coal deposits. Pyrite is a dense mineral (4.5 gm/cc)
compared with bituminous coal (1.30 gm/cc), but like coal
is quite water-insoluble unless oxidized.
The organic sulfur is a part of, and chemically bonded
to, the coal; it cannot be removed unless the chemical bonds
holding it are broken. The amount of organic sulfur present,
therefore, defines the theoretical lowest limit at which a
coal can be cleaned by physical methods. Where organic
sulfur is associated with certain constituents of coal,
gravimetric reductions may be possible; however, organic
sulfur is generally considered to be uniformly distributed
throughout the coal and not amenable to reductions by
conventional mechanical cleaning.
27
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Only the sulfide and sulfate sulfur forms in coal may
be removed by mechanical cleaning. The extent of that
removal, which is possible (10% to 90%) , is primarily a
function of particle size of the pyrite and the nature of
its dissemination. Very small and highly disseminated
pyrite particles are nearly impossible to separate from
coal. The pyrite may be of microscopic size and so
intimately mixed with the coal that it cannot be liberated,
or it may be predominantly coarse and readily released from
the coal when crushed. For a given situation, the removable
sulfur is the total sulfur less the sum of the organic sulfur
and that portion of the finely disseminated pyrite which
cannot be removed.
2.3 COAL RESERVES
Coal is found on every continent of the world,
including Antarctica, although most of the coal deposits are
found in the Northern hemisphere. According to the "Survey
of Energy Resources", World Energy Conferences, coal has
been mined in 70 countries of the world, however, 80% or
more of all identified coal reserves occur in the United
States, the Soviet Union and China.
Due to the many different methods used to estimate
coal reserves, and because available information on coal
varies widely, comparisons of the reserves between or among
countries is very difficult. The United States Bureau of
Mines and the United States Geological Survey data indicates
that the United States has at least one-fifth to one-sixth
of all the coal in the world. Approximately one-eighth of
the land area of the United States is underlain by coal-
bearing strata. These strata occur in at least 37 states.
Figure 2-5 depicts the coal fields of the United States.
28
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4OO *OO M'LCf
L0«-*0'0ttlt b'tummovt
|i Mtdium-OM high- »oioiilf biiummoul
CD Subbiluminout end Itgnilt (untfiff.)
£3 SuMiluminoui
> llOIOttd oceurrtnct o) cool 0f «nhno«n *ii«nt
*— AnNiraeiU S— Bi'w*"inou»
S- Subbilum.nout L- L'tn"»
Figure 2-5
The Coal Fields of the United States
(Source: U.S. Geological Survey)
In addition to indicating the geographic distribution
of coal, Figure 2-5 shows the range of coal ranks within
the United States. Nearly all the bituminous and
anthracite coal is found in the Eastern half of the country.
Although the full range of coal ranks is found in the
Western half of the United States, most Western coal
reserves are sub-bituminous coal or lignite. In most of
the coal-bearing areas shown in Figure 2-5, more than one
coal seam is present (from a few seams to 117 that have
been identified in West Virginia). The individual seams
range in thickness from a fraction of an inch to more than
100 feet. Most of the bituminous coal seams are 20 feet thick
thick or less and most mining has been in seams from 3 to 10
feet thick.
29
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According to;'the 1974 Keystone Coal Industrial Manual,
"The identified and hypothetical reserves of coal in the
United States amounts to some 3,224 billion tons. However,
based on current technology, economics and environmental
regulations, only some 150 billion tons could reasonably be
extracted".
There are three main classes of reserves. They are:
measured, indicated and inferred. They may be described as
follows:
1. Measured (proven) reserves lie within 1/2 mile
of a point of observation and are considered to
be within 20 percent of true tonnage.
2. Indicated (probable) reserves are based on points
of observation approximately 1 mile apart, but not
more than 1 1/2 miles, covering a band 1 1/2 miles
wide surrounding the area of proven reserves.
3. Inferred reserves, in general, lie more than 2
miles from points of observation. Sometimes this
category is broken into strongly inferred reserves,
which are estimated by projections beyond the 4
mile limit. The Bureau of Mines frequently reports
known reserves that represent the sum of measured
and indicated reserves.
In computing the volume of reserves in each of the
thickness categories for each bed, the total thickness of
coal is used, exclusive of partings greater than 3/8 of an
inch thick. Beds or parts of beds made up of alternating
layers of thin coal and partings are omitted if the total
partings exceed one half the total thickness or if the ash
content exceeds 33 percent. Frequently, the distribution of
reserves is also categorized according to thickness of
overburden: 0 to 1,000 feet, 1,000 to 3,000 feet and 3,000
feet to 6,000 feet.
The breakdown of total U.S. coal resources according to
Keystone is as follows:
30
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Billion Tons
Mapped and explored (identified)
0-3,000 ft. overburden 1,581
Unmapped and unexplored (indicated
and probable)
0-3,000 ft. overburden 1,306
3,000-6,000 ft. overburden .... 337
Total 3,224
However, the economically exploitable coal, which is defined
as "material having a thickness of more than 28 inches and
less than 1,000 ft. overburden..." and from identified
reserves, is stated to be less than 260 billion tons. Of
this figure, the United States Bureau of Mines says we will
recover 50% of the underground reserves (105 billion tons)
and 90%+ (45 billion tons) of the surface reserves for a
total of 150 billion tons.
The coal fields of the United States, identified by
regions and type of mining, are shown in Figure 2.6. The
Appalachian Region, which stretches northeastward from
Alabama through Tennessee, Virginia, West Virginia, Ohio
and Pennsylvania, is the largest deposit of high-rank
bituminous coal in the world, and contains most of the
anthracite coal in the United States.
One of the characteristics of the Appalachian Region
coals which enhances their value is their ability to form
coke or agglomerate when heated in the absence of, or with
a limited supply of air. All of the coals are not used for
coke-making, however, because some contain more sulfur than
is desirable for metallurgical-grade coke. We have more
information on the quality of these coals than for those
found in any other region in the country. This is due to
the many analyses of the coals made by Federal and State
agencies in connection with the use of these coals, not
31
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SURFACE MMMG REGIONS
Surfoce mining
region
1. Kentucky
2. West Virginia
3. Virginia
4. Tennessee
2. Indiana
3. Iowa
4. Ohio
Ragk»3
1. Pennsylvania
1. Colorado
2. Montana
3. NawMexico
4. Wyoming
Regions
1. Oklahoma
2. Kansas
3. Missouri
1. North Dakota
UNDERGROUND MMMG REGIONS
Underground mining
regions
1. West Virginia*
2. Pennsylvania
Reg»fi2
1. Mercer County. W. Va.
2. McDowell County. W Va
3. Wyoming County. W. Va.
R*gton3
1. Illinois
2. Indiana
3 Ohio
Region 4
1. Kentucky
2. Tennessee
3. Virginia
Regions
1. Utah
2. Colorado
Region 6
I. Alabama
•Iktn
-------
only for coke-making, but for light, power and heat in the
industrial, commercial and residential sectors of the
economy.
West Virginia ranks second to Illinois in total
bituminous coal reserves, but first in reserves of bituminous
coal among the states in the Appalachian Region.
Approximately 46 percent of West Virginia's reserves are
low-sulfur coals (here defined as 1.6 percent sulfur or
less) and 45 percent are medium-sulfur coals (3 percent or
less), making a total of 91 percent of the reserve having
relatively little sulfur.
West Virginia coals vary so greatly that it is
convenient to separate them as northern and southern coals.
In the North, the Pittsburgh bed produces medium-sulfur
coals, and the upper Freeport and Sewell beds produce low-
sulfur coals that are excellent for steam generation. In
the South, the Lower Kittanning, No. 2 Gas, Peerless, Cedar
Grove and Sewell beds produce some of the finest steam
quality coal mined in the United States. As the sulfur
content of these coals is generally low, only the ash content
needs to be reduced.
In Pennsylvania, large quantities of bituminous coal
are produced for electric utilities. Most of this coal comes
from the Upper and Lower Freeport, Upper and Lower Kittanning
and Pittsburgh coal beds. These are generally medium-sulfur
coals (85 percent of the reserve contains 3 percent or less
sulfur and 35 percent has a sulfur content of no more than
2 percent). The Central Pennsylvania beds, including both
medium and low-volatile coals, generally contain less sulfur
than those in the western part of the state and are upgraded
primarily to reduce the ash content before they are used for
steam generation.
33
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In Ohio the principal coal beds mined are extensions of
Pennsylvania's Pittsburgh, Middle and Lower Kittanning, Upper
and Lower Freeport and Sewickley (Meigs Creek) bed; these
coal beds usually contain medium-ash and high-sulfur. They
are used primarily for steam generation.
Maryland's coals are similar to those of the eastern
portion of the bituminous fields of Pennsylvania, but these
usually have low-sulfur content. In eastern Kentucky and
Virginia, the coals are of low-sulfur content. In Tennessee
and Alabama, the sulfur content of the coal ranges from low
to high.
Of the bituminous deposits, about two-thirds are located
in the states east of the Mississippi River. The coal fields
or deposits in Illinois, Indiana and western Kentucky contain
29 percent of the estimated remaining bituminous coal
reserve, but Illinois alone has the largest bituminous
reserve of all states. Coals in these states are generally
higher in sulfur, especially organic sulfur, with almost 80
percent of the reserved containing more than 3 percent sulfur.
There are, however, several small deposits of low-sulfur
coals in southern Illinois and Indiana where sulfur content
averages 1.5 percent or less.
The Interior Western region contains large deposits
of medium to high-volatile bituminous, which have not been
extensively mined because they are too far from the eastern
centers of population and industry. These deposits extend
across Iowa, Missouri, eastern Nebraska, Kansas and into
Oklahoma, with a related bed in Texas. A smaller area of
low-volatile bituminous and anthracite extends over into
Arkansas.
The small lignite beds in Texas and Arkansas extend
over into Alabama and are properly in the Gulf Province.
34
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They are of only fair quality and few analyses for them are
available. They have been included with the interior western
region in the USBM studies for convenience.
Coals in the Northern Great Plains province comprise
enormous deposits of lignite and subbituminous, which have
scarcely been touched. Lignite is characterized by a high
content of water and ash, and an ash content of alkaline
earths which is significantly higher than other coals.
The western region is defined here, as in the USBM
studies of coals by regions, to include the deposits in the
Rocky Mountain states and a few isolated deposits in the
Pacific Northwest. A southwest sub-region at the Four-
Corners area of Arizona, New Mexico, Utah and Colorado has
been established for washability data collection. The coals
of the western United States are geologically younger than
the eastern coals, and 70% are subbituminous or lignitic
in rank. Although the lower rank western coals are generally
of low-sulfur content and often contain only medium amounts
of ash, they also are of lower calorific value and are
mostly used for steam generation where they can be mined
easily and utilized close to their source. However, in
some recent applications, these coals are being shipped to
eastern steam generators.
On a broad regional level, only the bituminous coals of
South Appalachia and some of the lignites of the West will
directly, or with the best coal cleaning technology, meet the
most strict sulfur emission levels, although there are other
seams with substantial reserves which can comply. The coals
of North Appalachia, as a group, can be prepared to meet some
regional state implementation plans. Overall, the cleaning
of northeastern coals combusted for power generation would
result in 34% sulfur reduction (nearly 3 million tons af
35
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sulfur annually) utilizing current cleaning practice; this
level would be increased to 46% (over 4 million tons
annually) by the application of the best known preparation
technology.
36
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REFERENCES AND/OR ADDITIONAL READING
Allison, Ira S.; Black, R.F.; Dennison, J.M.; Fahnestock, R.K.; &
White, S.M., "Geology: The Science of a Changing Earth" (6th Ed.),
McGraw-Hill Book Company, New York, 1974
Baily, Ralph E., "Coal Industry Overview", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania May 1975
Barlow, James A., "Coal & Coal Mining in West Virginia", Coal Geology
Bulletin No. 2, February 1974
Brobst, Donald A. & Pratt, Walden P. (Editors), "United States
Mineral Resources", Geological Survey Professional Paper 820,
U.S. Government Printing Office, 1973
Clenderring, John A., "Palynological Evidence for a Pennsylvanian Age
Assignment of the Dunkard Group in the Appalachian Basin: Part II",
Coal-Geology Bulletin No. 3, West Virginia Geological & Economic
Survey, December 1974
Corp, Ernest L.,; Schuster, Robert L.; McDonald, Michael W., "Elastic-
Plastic Stability Analysis of Mine-Waste Embankments", U.S. Bureau
of Mines RI 8069
Dopples, Edward C.; Hopkins, M.E. (Editors), "Environments of Coal
Deposition (Special Paper #114)", Geological Society of American
Symposium, Miami Beach, Florida, 1964 (edited in Bouton, Colorado,
1969)
Goodrich, John C., "Computer Mapping of Coal Reserves by Sulfur Level",
Harvard University, Cambridge, Massachusetts, April 1971
Helfinstine, R.J., et al., "Sulfur Reduction of Illinois Coals—
Washability Studies, Phase II", Illinois State Geological Survey,
July 1971
Henderson, G.S.; Andren, A.W.; Harris, W.F.; Reichle, D.E.; Shugart,
H.H.; Van Hook, R.I., "Environmental Assessment of S0_ and Trace
Element Emissions from Coal Utilization", Coal Utilization Symposium-
Focus on SO Emission Control, Louisville, Kentucky, October 1974
Hill, George R., "Clean Fuels from Coal—The OCR Challenge", Mining
Congress Journal, February 1973
Hoffman, L; Truett, J.B.; Aresco, S.J., "An Interpretative Compilation
of EPA Studies Related to Coal Quality and Cleanability", Mitre
Corporation, May 1974 EPA 650/2-74-030
37
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Hoffman, L. et al., "Survey of Coal Availability by Sulfur Content:,
Mitre Corporation, May 1972
Hulett, L.D.; Carter, J.A.; Cook, K.D.; Emery, J.F.; Klein, D.H.;
Lyon, W.S.; Nyssen, G.A.; Fulkerson, W.; Bolton, N.E., "Trace
Element Measurements at the Coal-Fired Allen Steam Plant—Particle
Characterization", Coal Utilization Symposium-Focus on SO Emission
Control, Louisville, Kentucky 1974
Janssen, Raymond E., "Earth Science: A Handbook on the Geology of
West Virginia", Educational Marketers, Inc., Clarksburgh, West
Virginia, 1973
Jimeson, R.M.; Spindt, R.S., "Pollution Control and Energy Needs",
Advances in Chemistry Series, American Chemical Society, Washington,
D.C., 1973
Kennecott Copper Corporation, "Chemical Desulfurization of Coal",
American Mining Congress Coal Convention, May 5-8, 1974
Lawrence, William F.; Cockrell, Charles F.; Muter, Richard, "Power
Plant Emissions Control", Mining Congress Journal, April 1972
Leavitt, Jack M.; Leckenby, Henry F.; Blackwell, John P.; Montgomery,
Thomas L., "Cost Analysis for Development and Implementation of a
Meteorologically Scheduled SO Emission Limitation Program for Use
by Power Plants in Meeting Ambient Air Quality SO Standards",
TVA Air Quality Branch, Marcel Dekker, Inc., 1974
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Lowry, H.H. (Editor), "Chemistry of Coal Utilization", John Wiley &
Sons, Inc., New York, New York, 1963
Magee; Hall; Varga, "Potential Pollutants in Fossil Fuels", Environ-
mental Protection Technology Series, ESSO Research & Engineering
Company, June 1973
Massey, Lester G., "Coal Gassification", Advances in Chemistry Series,
American Chemical Society, Washington, D.C., 1974
Miller, R.E.; Agarwal, J.G.; Petrovic, L.J., "Economic & Technical
Considerations in the Use of Coal as Clean Fuel", American Mining
Congress Convention, May 6-9, 1973
38
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Nandi, S.P.; Walker, P.L., Jr., "Absorption Characteristics of Coals
and Chars", National Technical Information Service, Springfield,
Virginia, April 1972
National Coal Association, "Bituminous Coal Facts - 1970"
National Coal Association, "Coal Makes the Difference", 56th National
Coal Association Convention, June 1973
National Coal Associaiton, "Second Symposium on Coal Utilization",
NCA/BCR Coal Conference and Expo II, October 1975
Nelson, J.B., "The Assessment of the Mineral Species Associated with
Coal", British Coal Utilization Research Association Bulletin 7, 2
1953
Phelps, E.R., "Federal Coal Leasing Policy", American Mining Congress
Convention, October 1974
Resource Planning Associates, Inc., "Energy Supply/Demand Alternatives
for the Appalachian Region—Executive Summary", Council for Environ-
mental Quality, Appalachian Regional Commission and the National
Science Foundation, Report EQ-022, March 1975
Sage, W.L., "Combustion Tests on a Specially Processed Low-Ash, Low-
Sulfur Coal", National Technical Information Service, Springfield,
Virginia, 1964
Schaeffer, Stratton C.; Jones, John W., "Coal Preparation vs. Stack Gas
Scrubbing to Meet S0_ Ends
and Expo II, October 1975
Scrubbing to Meet S0_ Emission Regulations", NCA/BCR Coal Conference
Soderberg, H.E., "Environmental Energy & Economic Considerations in
Particulate Control", American Mining Congress Coal Convention,
May 5-8, 1974
Stacy, w.o.; Walker, P.L., Jr., "Structure and Properties of Various
Coal Chars", Pennsylvania State University, National Technical
Information Service, Springfield, Virginia, September 1972
Tieman, John W., "Chemistry of Coal", Elements of Practical Coal Mining,
Seeley W. Mudd Series, American Institute of Mining, Metallurgical
and Petroleum Engineering, Inc., New York 1968
39
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Tieman, John W., "Geology of Coal", Elements of Practical Coal Mining,
Seeley W. Mudd Series, American Institute of Mining, Metallurgical
and Petroleum Engineering, Inc., New York, 1968
Tompos, E.f "Detailed Investigation of Pyrites Distribution, Taking
Account of the Petrographic Components of Coal, with a View to
Reducing the Pyrites Content in Coking Coal", Hungary, Australian
Coal Conference
U.S. Bureau of Mines, "Bituminous Coal and Lignite Shipments from
Coal Producing District by Ranges of Sulfur Content (Calendar Year
1970)", Division of Fossil Fuels, 1973
U.S. Bureau of Mines, "Clean Energy from Coal Technology", Overview of
Coal/Energy Usage, U.S. Government Printing Office, 1974
U.S. Bureau of Mines, "Coal—Bituminous and Lignite in 1973", Division
of Fossil Fuels, U.S. Department of Interior Mineral Industry
Surveys, January 1975
U.S. Bureau of Mines, "Commodity Data Summaries - 1976"
Volsicky, Z.; Puncmanova, J.; Hosek, V.; Spacek, F., "Bacteriological
Leaching-Out of Finely Intergrown Sulfur in Coal: Method and
Features", Czechoslovakia, Australian Coal Conference
West Virginia Geological & Economic Survey, "Suitability of West
Virginia Coals to Coal Conversion Processes", Coal-Geology Bulletin
No. 1, December 1973
Williams, Cyril H., Jr., "Planning, Financing and Installing a New
Deep Mine in the Beckley Coal Bed", Mining Congress Journal,
August 1974
Yancey, J.F.; Geer, M.R., "Behavior of Clays Associated with Low-Rank
Coals in Coal-Cleaning Processes", U.S. Bureau of Mines Report of
Investigations #5961
Yancey, H.F., "Determination of Shapes of Particles in Coal and Their
Influence on Treatment of Coal by Tables", AIME Translation, 94
Zitting, Richard T., "Solid Fuels: Their Contribution to Energy
Independence", American Mining Congress Convention, October 1974
40
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3. OBJECTIVES OF COAL PREPARATION
3.1 BACKGROUND
Coal often exists in its natural state with many
impurities, i.e., sulfur, clay, rock, shale and other
inorganic materials generally called ash. During the past
decade increasing emphasis has been placed on removing the
impurities, especially those which result in sulfur oxide
emissions upon combustion of the coal.
Historically, in the United States coal preparation
has been utilized only for specific coals destined for
carbonization. The reasons are varied; primarily to reduce
their sulfur content, to provide a specific uniform product,
to enhance salability, and to improve the economic advan-
tages for coal marketing by developing a superior product.
The technological and economic growth of the last 25 years,
the resulting degradation of our Nation's environment and
the introduction of emission standards for air pollution
control (sulfur oxides) have changed this picture
considerably in recent years.
Years ago, in the hand-loading days of our coal
industry, the quality of coal produced was generally
satisfactory (regardless of use) because only the cleanest
seams were mined and the majority of impurities inherent in
mining operations were not loaded out with the coal.
However, productivity per man was very low. Mechanization
improved productivity, but impurities increased to the
41
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extent that some form of cleaning became necessary at many
mines, even those in the cleanest seams. The transformation
from hand-loading to mechanical mining was quite rapid
during the mid 1930's. Tipples and earlier type cleaning
devices became inadequate almost overnight. The quality
of coal was jeopardized again with the adoption of full-
seam mining throughout the industry. Cleaning units were
installed on coarse coal sizes to eliminate the manpower
required for hand picking the coal as it came from the mine.
In addition, due to the marked increase in finer sizes in
the run-of-the-mine coal called "ROM", cleaning units were
installed to pick up the slack in the coal output.
Today with the thinner dirtier seams being mined, the
impurities in the raw coal may be not only from the seam
itself, but also in extraneous material taken in mining
of the roof or floor. With increased mechanization, a
higher proportion of top and bottom material is taken in
mining, which increases the tonnage of reject to be handled.
Also, the effects on mining practice of the coal mine Health
and Safety Act of 1969 have contributed significantly to
the increase in impurities in the ROM coal. For example,
the water sprays on continuous miners used to ally the dust
at the face seem to add significantly to the moisture
content of the raw coal while excessive rock dusting adds
other incombustibles to the ROM coal.
3.2 CURRENT PRACTICE
Coal is providing an increasing share of energy
consumed by stationary sources (utility, industrial,
commercial and residential). Demand for electrical energy,
the shortage of available oil and gas and stagnation of
nuclear power development, have made critical the issue as
to whether energy can be made available, in its desired
forms, to meet future demands without sacrificing the
environment.
42
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Today raw coal is cleaned to remove as much non-
carbonaceous material as is economically feasible in order
to produce a uniform high-quality feedstock for any
desired use. Some of the reasons for coal preparation are:
removal of substantial quantities of sulfur
from coal,
concentration of carbon in the clean coal,
removal of ash,
reduction in concentration of trace elements and
uniform quality of product including ash,
moisture and Btu content.
Coals have highly variable characteristics by seam and
by geographical location. Coals are prepared by size
reduction and sorting, based upon particle size and density,
to create uniform products of high calorific content and
reduced mineral levels; especially sulfur. However, only
the pyritic sulfur fraction of the total sulfur content is
amenable to separation by physical processing. This
limitation of sulfur reduction to the natural organic sulfur
level of a particular coal means that the level of coal
quality improvements attainable is varying, being constrained
by processing objectives, cost, processing technology and
coal characteristics.
The specific ways of preparing coal are of course
determined by its end use. Most of the coal produced in
this country is consumed either by carbonization--to
produce metallurgical and chemical coal—or by combustion--
to raise steam for electric power generation, to obtain
process heat and steam for manufacturing and mining industries
or for space heating. Although many of the same methods
are used in evaluating coals for different uses, the
43
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problems, bodies of knowledge and approaches associated with
carbonization and combustion in each area are sufficiently
dissimilar that coal evaluation in each area merits separate
discussion.
3.3 METALLURGICAL COKE
Another fuel form, metallurgical coke, is almost
universally used in blast furnaces, both in ferrous and
non-ferrous smelting. Coke is the hard, condensed residue
resulting from the slow combustion of bituminous coal in the
absence of air. This process distills and drives off the
volatiles and leaves a high-carbon product, i.e., coke.
During decomposition, the coal mass fuses and swells
and becomes plastic. The volatile substances driven off
during the coking process range from simple gases such as
CO, C02, H20, H2, N2, CH4, H2S, S2 and NH3 to various
complex hydrocarbons and other organic compounds, some
containing nitrogen and sulfur. Gradually the mass
solidifies as the process reaches completion.
The by-product coke oven, as shown in Figure 3-1, is
the primary tool for processing coke in the United States.
The oven is externally heated and allows for the recovery of
the coal gases, coal tar, and other valuable by-products.
Not all coals are suitable for coking purposes and
those that are selected must be carefully prepared before
carbonization to produce a high quality coke. The main
purpose in cleaning coals is to reduce moisture, ash and
sulfur content; however, coal is also prepared to obtain a
uniform product. This is important because coal often
varies in quality in different areas of a mine. By prepar-
ing the coal, a blending of the various qualities can be
achieved to assure a uniform coke with minimum ash and
sulfur content.
44
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When used for metallurgical purposes, the presence of
sulfur compounds in the fuel represents a genuine problem.
For example, in high or vertical furnace processes a
lowering of the sulfur content in coke by 1 percent saves
from 18 to 20 percent of the fuel, considerably increasing
the efficiency of the metallurgical aggregates and
contributing to an improvement in the quality of the metal,
Also, sulfur in coal used for metallurgy is apt to
contaminate the metal. This holds equally true for
several other elements which comprise the ash content of
coal such as phosphorous and arsenic.
Cool charging car
9 Gas main to
by-product plant
Coke
Quenching
cor
Figure 3- 1
By-Product Coke Oven
3.4 STEAM COAL
About two-thirds of the electric energy in the United
States is generated by coal-fired plants. Many of these
plants use high-sulfur coal although increasingly more
stringent Federal, State and local air pollution regulations
45
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have intensified the demand for clean fuels and superior
control devices.
The major problem of coal-burning power plants is
reducing the air pollutants in stack gases. In most of
these plants, a chief pollutant is sulfur dioxide from the
combustion of organic sulfur compounds present in the coal.
Stack gas cleaning systems are expensive to install and
operate, and in some cases would not be needed if most of
the pollutants were removed from the coal prior to
combustion.
The sulfur dioxide standards now applicable to the
power industry include Federal regulations which primarily
relate to new facilities and those imposed by the
individual State Implementation Plans (SIP's). These
regulations apply to steam generating facilities which
were started or modified after August 17, 1971, within 180
days of the time they came on-line. They apply to all
facilities having more than 250 million Btu/hour input
(about 10 tons of coal). Besides the maximum 2 hour average
value of 1.2 pounds S02 per million Btu fired, corresponding
values for particulate matter are 1.0 pound and no greater
than 20% opacity, and for nitrogen oxides, 0.7 pounds per
million Btu fired.
Estimates made in accordance with Project Independence
(the President's plan for the United States to be energy
self-sufficient by 1985) call for the demand of coal to
expand to between 1.2 and 1.7 billion tons per year by
1985. About 94 billion tons of naturally occurring low
sulfur coal can be foreseen as a supply that meets air
quality regulations. The remaining portion will have to be
regulated by using control devices or by coal preparation.
46
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Available methods for controlling sulfur oxide
emissions from stationary combustion sources fall into the;
following major categories:
the physical removal of pyritic sulfur by physical
coal cleaning prior to combustion,
the scrubbing of sulfur oxides from the combustion
flue gas and
the conversion of coal to a clean fuel by such
processes as gasification, liquifaction and
chemical extraction.
Of these methods, physical removal of pyritic sulfur is
the least expensive and the most highly developed method.
The degree of sulfur reduction possible depends upon the
characteristics of the raw coal and its amenability to
sulfur release upon crushing. These characteristics are
unique to specific coals and vary from coal to coal. Until
such time as new coal conversion technology becomes available
and economical, most sulfur oxide emission control will be
affected by physical coal cleaning, flue gas scrubbing or
a combination of both.
Additionally, the use of coal in coal fired plants with
high ash content results in a greater loss of efficiency,
yields a greater amount of ash and leads to greater losses
in the flue gases. Also, the loss of sensible heat and
combustible matter in the ash is. greater and the cost of
drying is correspondingly increased.
With the exception of coal used by some stokers or wet
bottom furnaces, coal used in utility power plants is
normally pulverized. The cost of grinding and the wear and
tear of the pulverizers are disproportionately increased if
the coal has a high ash content because the shale is harder
to grind than the coal. Furthermore, the mineral matter in
the dust entering the combustion chamber must be heated to
the flame temperature without contributing anything to the
47
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heating and the incombustible dust must be discharged from
the furnace. The flue gases generally carry large quantities
of incombustible dust which is either discharged through
the stack or accumulates on the stack walls.
Other than poor design or operation, the quality of the
coal greatly effects the efficiency of the combustor. In
addition to the operational costs and problems, the
increased transportation costs (transporting moisture and
other impurities) and the increased disposal cost of the ash
add considerable emphasis to the merits of clean coal.
3.5 SUMMARY
Coal is used in sintering, pelletizing, zinc retort
smelting, blast furnace smelting and other metallurgical
processes. For these processes, special coals prepared to
rigid specifications are used to get the desired
metallurgical results at lowest cost. By far the largest
s
application is in the form of coke for the iron blast
furnace.
Coal is also becoming the primary fuel for steam
generation for electric utilities. The mechanical coal
cleaning process will allow certain coals to be combusted
without additional sulfur emission controls and in those
situations where such controls are still necessary, prior
coal cleaning helps reduce the emission control costs.
For whatever purpose coal or coke is used, it is to the
advantage of the consumer that the fuel should contain the
minimum amount of ash. Incombustible material in the fuel
reduces its gross calorific value, increases the weight that
must be handled and transported, gives rise to difficulties
of combustion and involves further expense in its disposal.
Also, ash in coal increases the production of smoke and
results in the discharge of fine dust from chimney stacks,
especially from the stacks of pulverized fuel boilers.
48
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It is clear that with an increasing electric load
generated by coal, the emission of S02 into the atmosphere
must be kept at an acceptable level. There have, however,
been difficulties in perfecting SC>2 clean-up systems and
processes. Most estimates indicate that these processes
will not reach widespread commercial usefulness before the
mid-1980"s because of chemical and mechanical problems.
This fact, coupled with the need to meet stringent air
quality standards passed by the Federal Government, provide
the rationale for preparing raw coal to remove as much
pyritic sulfur as possible before firing.
Clean coal's greatest applicability is to:
(1.) installations which are not able to use flue gas
desulfurization, such as industrial boilers of small size,
and (2) existing combustors which require clean coal to
meet State Implementation Plans (SIP's).
49
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REFERENCES AND/OR ADDITIONAL READING
Agarwal, J.C.; Giberti, R.A.; Irminger, P.P.; Petrovic, L.J.; &
Sareen, S.S., "Chemical Desulfurization of Coal", American Mining
Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Allison, Ira S.; Black, R.F.; Dennison, J.J.; Fahnestock, R.K.; &
White, S.M., "Geology: The Science of a Changing Earth" (6th Ed.),
McGraw-Hill Book Company, New York, 1974
Bailey, Ralph E., "Coal Industry Overview", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania May 1975
Barlow, James A., "Coal & Coal Mining in West Virginia", Coal Geology
Bulletin No. 2, February 1974
Battelle-Columbus, "SO Control: Low-Sulfur Coal Still the Best Way",
Power Engineering, November 1973
Brobst, Donald A. & Pratt, Walden P. (Editors), "United States
Mineral Resources", Geological Survey Professional Paper 820,
U.S. Government Printing Office, 1973
Cutler, Stanley, "Emissions from Coal-Fired Power Plants", U.S.
Department of Health, Education and Welfare, 1976
Dopples, Edward C.; Hopkins, M.E. (Editors), "Environments of Coal
Deposition (Special Paper #114)", Geological Society of American
Symposium, Miami Beach, Florida, 1964 (Edited in Bouton, Colorado,
1969)
Engdall, R.B., "A Critical Review of Regulations for the Control of
Sulfur Oxide Emissions", Battelle Columbus Laboratories, APCA
Journal, Vol. 23, #5, May 1973
Environmental Protection Agency, "Air Pollution Technical Publications
of the Environmental Protection Agency, Research Triangle Park, North
Carolina, July 1974
Jimeson, R.M.; Spindt, R.S., "Pollution Control and Energy Needs",
Advances in Chemistry Series, American Chemical Society, Washington,
D.C., 1973
Journal of the Air Pollution Control Association, "Panel Calls Bene-
ficiation-FGD Combination 'Most Economical, Best Ail-Around Choice1",
November, 1975
Lawrence, William F.; Cockrell, Charles F.; Muter, Richard, "Power
Plant Emissions Control", Mining Congress Journal, April 1972
50
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Schaeffer, Stratton C.; Jones, John W., "Coal Preparation vs. Stack Gas
Scrubbing to Meet So Emission Regulations", NCA/BCR Coal Conference
and Expo II, October 1975
Soderberg, H.E., "Environmental Energy & Economic Considerations in
Particulate Control", American Mining Congress Coal Convention,
May 5-8, 1974
51
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THIS PAGE INTENTIONALLY LEFT BLANK
52
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4. THE PREPARATION PROCESS
4.1 OVERVIEW
The coals of the United States have highly variable
characteristics by seam and by geographic location. Since
coals vary so widely, coal cleaning processes are typically
engineered for each coal source and designed with respect
to the use to be made of the coal. There is a considerable
process uniformity among plants, but each plant is usually
individually designed.
Coals are prepared by size reduction and subsequent
particle sorting based upon particle size and density. The
level of coal quality improvements attainable is variable,
being constrained by processing objectives, cost,
processing technology and coal characteristics.
For years, preparation plants were designed to produce
multiple sizes of coal for various customers, such as lump,
egg, stove, stoker and nut sizes. Today, however, plants
are designed to produce only one product of definitive
characteristics for one specific customer. The preparation
plant is designed to remove the non-combustibles from the
coal at the minimum practical operating cost and at the
optimum practical yield. However, the ROM coal is
prepared only to the extent that is necessary to make the
product salable.
The range of coal cleaning processes now being prac-
ticed in the United States may be generalized into four
53
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individual levels of preparation. These levels may be
defined as follows:
Level 1—no preparation, direct utilization of
the run-of-the-mine product.
Level 2—removal of gross non-combustible impuri-
ties, plus control of particle size and promotion
of uniformity (typically 95% material yield and
99% thermal recovery). Little change in sulfur
content.
Level 3—single-stage cleaning allowing little
component liberation. Particle sizes less than
3/8 inch usually are not prepared. 80% material
yield and 95% thermal recovery. Limited ash
and sulfur content.
Level 4—multi-stage cleaning with controlled
pyrite liberation. Usually incorporated
dewatering and thermal drying. 70% material
yield and 90% thermal yield. Maximum ash-sulfur
rejection, and calorific content of product.
Preparation practice for most coals used by electric
utilities lies between levels 2 and 3. The preparation
practices for metallurgical coals are typically level 4.
The relative costs of these different levels are indicated
in Table 4-1. The extent to which a specific coal can be
cleaned is dependent upon the characteristics of the coal
and the sophistication of the preparation process. The
limitations are often both economic and technical.
The technical limitations of the preparation process
relate primarily to the very small component particles
existing in coal. Many of these particles are residual
structures of vegetation and minerals, generally irregular
in shape. The pyrite particles in many coals are less than
1 micron (0.0004 inch) in their longest dimension. Parti-
cles smaller than 50 microns cannot be practically separated
from each other, and separating them is usually inefficient.
Larger particles, or those less homogeneous in composition,
respond more readily to separation.
54
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CLEAN COAL
STORAGE
REFUSE BIN
REFUSE CONVEYOR
PREPARATION
PLANT
TRUCK DUMP
J.J.DAVIS
AS S O C I ATE S
The Modern
Preparation Plant
Figure 4-1
DCN
-------
TABLE 4-1
PREPARATION PLANT CAPITAL AND OPERATING COSTS1
Eastern Bituminous Coal
Design Capacity
Clean Coal
Tons/Yr
3,000,000
2,000,000
1,000,000
Western Subbituminous
Utility Coal2
10,000,000
5,000,000
3,000,000
2,000,000
1,000,000
Cleaning Cost $/Ton5
Level 4
o.so-*
1.744
Level 3
0.45J
0.874
Level 2
$25,200,000
17,500,000
9,000,000
$11,200,000
8,100,000
4,350,000
$3,200,000
2,500,000
1,500,000
6,720,000
3,360,000
2,040,000
1,580,000
1,200,000
0.053
0.174
0.056
0.126
Mid-1974 dollars
Level 4 - Detailed, elaborate facility (75% recovery).
Level 3 - Removal of liberated mineral matter (75% recovery).
Level 2 - Removal of only gross mineral matter (95% recovery).
Only Level 1 or 2 is applicable.
necessary.
Lignite - Level 1 only considered
3. Includes labor, power, maintenance - no amortization or return on
investment. Thermal drying adds about 25% to capital costs and
30% to operating costs.
4. Includes straight line financing at 8% interest, 20 years life and
5% ROI.
5. Eastern Bituminous coal cleaning - three million ton per year.
6. Western Subbituminous coal cleaning - ten million ton per year at
Level 2.
7. The capital costs utilized for cleaning eastern bituminous coals at
Level 4 ranged between $23,000 and $25,000 per ton of raw feed capa-
city per hour. Utilizing the "Best Practice" cited in Table 4-2
would increase this value to about $30,000 per ton of raw feed capa-
city per hour. The value would increase to an estimated $40,000 per
ton hour if the "best Cleaning Technology Available" were developed.
56
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To be separable, impurity-containing particles must
have masses greater than the pure coal particles. The
difficulty in separating small size particles (less than
50 microns) results from their slower response to the
acceleration of gravity than larger particles; they
literally float within the coal. Moreover, since most of
the separation is done in water systems, a further compli-
cation exists in working with small particles in that
removal of the water from them is significantly more
difficult and more costly than removing water from the
larger-sized particles due to the smaller porosity of the
smaller particles or of the combination of particles.
Because of the technical difficulty in separating small
particles, the separation costs increase as the particle
size decreases. The processes which will remove more
pyrite from the coal necessarily utilize smaller particle
sizes and are considerably more costly. Accordingly, coal
cleaned primarily for ash removal is cleaned with as large
a particle size as is practical. It is for this reason
that coal processing plants which were not designed for
sulfur removal often do not function well as pyrite
removers.
The economic limitations of coal preparation are
varied and numerous. Cleaning of coarse coal is relatively
simple and less costly than cleaning of the finer sizes.
The fine coal portion in the raw coal feed has materially
increased as mechanization of mining process has increased,
thus adding considerably to cleaning plant costs. Wet
cleaning units for fine coal are not themselves expensive;
it is the equipment necessary to dewater and dry the product
that adds significantly to the cost. Clarifying the process
water and thermal drying substantially increase plant
capital investment. Yet many modern cleaning plants must
57
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contain this equipment in order to obtain the desired ash,
sulfur and moisture in the product and still recover the
greatest amount of salable coal.
The disposal of waste refuse developed during the coal
cleaning process (CCP) represents an additional cost which
must be attributed to the preparation plant. Sample
capital and operating costs for several coal refuse
disposal operations in Kentucky and Alabama have been
developed. In 1969 dollars, these values were about $0.27
per ton of refuse or $0.09 per ton of salable clean coal.
To that, an additional cost of about $0.01 per ton of
refuse must be added for final disposal site reclamation.
These costs do not incorporate any consideration of land
values.
The cost of refuse disposal depends upon:
Distribution between coarse and fine refuse
sizes: For example, fine refuse poses similar
problems to the disposal of flue gas desulfuri-
zation sludge, and poses even more severe
potential water pollution problems. Coarse
refuse disposal costs about twice that of fine
refuse disposal while the latter may require
greater land area and more complex engineering.
Research continues to develop procedures to
convert the fine refuse to more dense and
manageable form. Labor and maintenance costs
are higher for coarse refuse disposal while
power costs are greater for fine disposal when
they must be pumped away.
Distance from preparation plant to disposal area.
Local topography and land availability for
disposal site construction.
Existing or impending environmental controls.
In addition, coal preparation processes are consumers
of energy—they both utilize it in the processing and lose
some of it in the rejected refuse. Most energy consumed
during coal processing is utilized for one of the following:
58
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to move the coal components through the cleaning
system,
to create new surface area by breaking or
crushing,
to activate equipment to manipulate the particle
separation,
to remove water from the coal and
to operate environmental protection systems.
In general, processing energy requirements increase with
the beneficiation level and decrease as particle size
increases.
Among the factors which may determine the final
delivered cost of coal to an electric generating station
are:
the cost of run-of-the-mine coal at the mine
portal,
the cost of cleaning,
the cost of handling and disposal of preparation
plant refuse,
the level of clean coal yield and thermal
recovery,
the cost of coal storage at the mine, preparation
plant and generation station,
the cost of coal loading at the mine or prepara-
tion plant and unloading at the generating
station and
the transportation costs.
Other economic impacts which must be compared between
use of run-of-the-mine coal and clean coal are:
the pulverization costs (power consumed and plant
maintenance) and
59
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the disposal cost of ash developed during coal
combustion.
The economic implications of coal preparation are presented
in Table 4-2 comparing sample costs for the same coal
burned "as mined" and cleaned. The clean coal, with a
0.6% lower cost, on a weight basis is 5.2% higher cost in
terms of C/MM Btu or mills/KWHr generated. This cost
comparison model neglects several factors which are diffi-
cult to quantify, but would undoubtedly enhance the value
of prepared coal. Among the factors favoring clean coal
are:
greater reliability of power plant performance,
reduced coal handling costs and storage costs,
greater heat-release capabilities—boiler
capacity design,
reduced slag-fouling maintenance in boiler and
heat transfer systems and
reduced quantities of fly-ash for collection.
4.2 PREPARATION PLANT MODULES
The physical cleaning of coal may be categorized into
five general processes'" when examined strictly in relation
to the preparation plant. These are:
plant feed preparation,
raw coal sizing,
raw coal separation,
product dewatering and/or drying and
product storage and shipping.
The sizing, separation and dewatering processes may each
be further broken down into three sub-processes which are
used for coarse, intermediate or fine sized coal,
respectively.
60
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TABLE 4-2
COMPARATIVE COAL COSTS FOR UTILITY CONSUMPTION UTILIZING
CLEANED COAL AND RUN-OF-MINE FROM THE SAME MINE
BASIS: 1 TON CLEANED COAL
Prepared Coal Run-of-Mine Coal
Value at shipping point
$ expression
C/MM Btu
mils/KWhr
Value at Utility (Includes Transportation)
$ expression
C/MM Btu
mils/KWhr
Value as fired (includes coal grinding costs)6
S expression
C/MM Btu
mils/KWhr
Total fuel costs at utility (includes ash disposal)
S expression
C/MM Btu
mils/KWhr
14.46-
52.20
5.35
18.25
65.90
6.76
18.38
66.40
6.80
18.62
67.20
6.89
13.31J
45.30
4.64
17.86
60.70
6.23
18.14
61.70
6.33
18.73
63.70
6.53
Basis for Comparative Cost Calculations
Coal Data
Clean Coal Yield 83.20%
Thermal loss in cleaning 5.85%
Heat Content (Btu/lb)
Run-of-Mine 12,240
Clean Coal 13,850
% increase 13.20
Ash Content (Ht. %)
Run-of-Mine 16.40
Cleaned coal 7.90
% decrease 51.80
61
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TABLE 4-2 (Continued)
COMPARATIVE COAL COSTS FOR UTILITY CONSUMPTION UTILIZING
CLEANED COAL AND RUN-OF-MINE FROM THE SAME MINE
1. Based on Central Pennsylvania low volatile bituminous coal. Assessed
at $14.46/T based on average U.S. selling price for utility coal,
May 1974. This price was equivalent to 65.8C/MM Btu, and represents
an average calorific content of 11,000 Btu/lb SOURCE: Federal
Power Commission Data. Coal News. No. 4226, 1/14/74. National
Coal Association, Washington D.C. It is further assumed for this
example that the figure of $14.46/T includes $1.80/T contribution
to the UMWA Royalty Fund.
2. Assumed cleaning cost $1.50/T of clean coal. A constant moisture
content of run-of-mine and cleaned coal is assumed.
3. Value of run-of-mine coal $9.28/T. 1.20 tons required to prepare
1.00 ton of clean coal. Upon direct sale of the run-of-mine product,
the $1.80/T UMWA Royalty would be added.
4. 1971 U.S. average for coal: 10,252 Btu used to generate 1 KWhr.
5. Assumed shipping cost $3.79/Ton (for 1973). SOURCE: Coal Traffic
Annual, 1974 edition, p. 27. National Coal Association, Washington
D.C. The cost advantages of storage and handling 20% less coal
in cleaned form at the power station have not been included.
6. The grinding of coal for pulverized firing to 70% minus 200 mesh
requires energy consumption which varies with coal hardness.
Hardness is usually expressed as Hardgrove Grindability Index.
A 55 HGI coal uses 7.9 KWhr/T, while a 100 HGI coal uses 4.4 KWhr/T.
For these calculations power was charged at 3 cents per KWhr. The
value for the softer coal was utilized for clean coal while the
harder coal value was used for run-of-mine coal. SOURCE: Private
communication - Mr. Richard Borio. Combustion Engineering, Inc.
Windsor, Conn. February, 1975.
7. Calculations based upon $3.00/Ton for ash disposal at the utility.-
Source of Table: Lovell, Harold L., Sulfur Reduction Technologies
in. Coal by Mechanical Beneficiation (Third Draft),
Pennsylvania State University, March 5, 1975.
62
-------
The preparation plant module diagram, Figure 4.2,
graphically portrays the major module categories. In
addition, this chart shows the main refuse streams at their
points of origin. The individual processes may be defined
in the following manner:
Plant feed preparation—This process is pri-
marily an initial size check, an initial size
reduction and the storage of the raw coal. The
raw coal storage may be either open or closed.
Open storage typically refers to piles of coal
stored upon the ground (usually conical).
Closed storage refers primarily to raw coal
that has been stored in a closed silo, generally
from 2,000 to 5,000 tons capacity. The initial
separation and reduction is normally performed by
a rotary-type breaker which separates ROM only
as being over six inches or under six inches.
Any product that is over six inches and passes
the breaker is directed immediately to the coarse
refuse disposal pile. All other product is
impact reduced by the breaker and fed directly to
the preparation plant or to the storage area.
Raw coal sizing—Raw coal sizing typically
consists of a primary size check and a secondary
size check which separates the coal into coarse,
intermediate or fine sizes. Primary sizing is
usually accomplished by a raw coal screen or a
scalping deck which separates the coal into
coarse or intermediate sizes. The coarse product
is reduced in size as necessary (usually 2" or
1 1/4" x 0), and returned to the sizing operation.
A secondary size check which is either a wet or
dry vibrating screen separates the intermediate
sizes from the fines and directs the product to
module three - raw coal separation.
Raw coal separation—This process works with the
coarse, intermediate or fine sizes, and has
unique separation processes suited to the three
individual size groupings. Most of these proces-
ses are based upon gravity separation of the coal
from the unwanted impurities. After separation,
the products are directed to module four - product
dewatering.
63
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1.
PLANT FEED
PREPARATION
RUN OF MINE STORAGE
3
2.
RAW COAL
SIZING
3.
RAW COAL
SEPARATION
DEWATERING
SHIPPING
2
5.
PRODUCT STORAGE
AND SHIPPING
J.J.DAVIS
ASSOCIATE S
Preparation Plant
Modules
Figure 4-2 I DCN
64
-------
Product dewatering and/or drying—This includes
dewatering and drying of the coarse and inter-
mediate sizes and an individual dewatering,
possibly with a thermal drying process, for the
fines.
Product storage and shipping—This includes
storage, handling and shipping operations and
may take a variety of forms.
The level of detail for any individual module is
variable and directly dependent upon the number and the
degree of complexity of the individual components that
comprise the operating tools. For example, plant feed and
initial product sizing are usually straightforward
operations (operationally and from the potential for
environmental impact and the ease of environmental control)
However, product separation is extremely variable in
regard to the number of possible combinations of equipment,
the influence of the specific coals, refuse or by-product
generation, etc. Therefore, within the product separation
module, the level of detail of module or sub-module
development may be considerable. Each of the process
modules will be discussed in separate chapters.
As with any operation involving man, materials and
machinery, there are a multitude of individual units or
combinations of units available to perform any specific
operation or task. For the purposes of the manual only
those units or combinations of units that are most typical
will be discussed; esoteric units will be discussed only
where their uniqueness or future benefit to the coal
cleaning process merit special attention.
65
-------
REFERENCES AND/OR ADDITIONAL READING
Bituminous Coal Research, Inc., "An Evaluation of Coal Cleaning
Processes and Techniques for Removing Pyritic Sulfur from Fine
Coal", BCR Report L-339, September 1969, BCR Report L-362, February
1970, BCR Report L-404, April 1971, BCR Report L-464, April 1972
Carta, M.; Del Fa, C.; Ciccu, R.; Curreli, L.; Agus, M., "Technical
and Economical Problems Connected with the Dry Cleaning of Raw
Coal and in Particular With Pyrite Removal by Means of Electrical
Separation", Italy, Australian Coal Conference
Coal Age, "Coal Preparation and Unit-Train Loading", July 1972
Coal Age, "The Coming Surge in Coal Preparation", January 1976
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Environmental Protection Agency, "Air Pollution Technical Publications
of the Environmental Protection Agency, Research Triangle Park, North
Carolina, July 1974
Foreman, William E., "Impact of Higher Ecological Costs and Benefits
on Surface Mining", American Mining Congress Coal Show, Detroit,
Michigan, May 1976
Gospodarka, Gornictwa, "Possibilities of Mechanical Preparation Under-
ground", 1956 No. 4
Grimm, Bobby M., "Preparation Plant Corrosion Cost", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
Hill, George R., "Clean Fuels from Coal—The OCR Challenge", Mining
Congress Journal, February 1973
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracity in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Jenkinson, D.C., "Some New Coal Preparation Developments in the United
Kingdom", National Coal Board Bulletin M4-B148
66
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Johakin, J., "Solving the SO Problem—Where We Stand with Application
and Costs", Coal Age, May 1975
Katen, Ken P.; Palowitch, Eugene R., "Shortwall vs Conventional Systems",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May, 1975
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
Kuti, Joe, "Longwall vs. Shortwall Systems", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania, May 1975
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Llewellyn, Robert L., "Coal Preparation", Elements of Practical Coal
.Mining, Seeley W. Mudd Series, American Institute of Mining,
Metallurgical and Petroleum Engineering, Inc., New York, 1968
Lotz, Charles W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Lovell, Harold L., "Sulfur Reduction Technologies in Coal by Mechani-
cal Beneficiation (3d Draft)", Commerce Technical Advisory Board
Panel on SO Control Technologies, March 1975
McNally-Pittsburg Manufacturing Corporation, "Coal Cleaning Plant
Prototype Plant Design Drawings", Department of Health, Education
and Welfare Contract 22-68-59
McNally-Pittsburg Manufacturing Corporation, "Coal Preparation
Manual #572", Extensive Analysis on McNally-Pittsburg Coal Cleaning
Technology
Roberts & Schaefer Company, "Manufacturers Information Booklets",
Chicago, Illinois
Roberts & Schaefer Company, "Design & Cost Analysis Study for Proto-
type Coal Cleaning Plant", August 1969
Roberts & Schaefer Company, "Research Program for the Prototype Coal
Cleaning Plant", January 1973
U.S. Bureau of Mines, "Clean Energy from Coal Technology", Overview
of Coal/Energy Usage, U.S. Government Printing Office, 1974
67
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THIS PAGE INTENTIONALLY LEFT BLANK
68
-------
5. PLANT FEED PREPARATION AND RAW COAL STORAGE
5.1 OVERVIEW
The plant feed preparation and raw coal storage module
consists of an initial size check, initial size reduction
and storage of the raw coal before it is fed to the pre-
paration plant. This module is highlighted in Figure 5-1.
The first step in the coal cleaning process is the
delivery of the run-of-the-mine (ROM) coal to the plant
site. The coal may be delivered in railroad cars from
distant mines, by trucks from the strip pits or by
conveyors or mine cars from the working faces in under-
ground mines. The equipment for raw coal handling starts
underground at the mining headhouse or at the truck dump
at surface mines. For example, some underground mining
sections have surge feeders which are equipped with
breakers to reduce the top size of the coal before it is
discharged onto the conveyor belt or into the mine cars,
and the truck dump itself at some surface mines may serve
to reduce the initial size of the ROM coal either from
impact breakage or crushing by the weight of the coal pile.
We will not address at this point the transportation
of the ROM coal to the plant site; however, it is important
to recognize in the preparation plant design the condition
of the coal as it comes from the mine.
5.2 INITIAL SIZE CHECK
ROM coal may contain very large pieces of rock, wood
or other impurities as well as coal. The method of mining
69
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COARSE
REFUSE
1.
PLANT FEED
PREPARATION
2.
RAW COAL
SIZING
SIZE REDUCTION
2
RUN OF MINE STORAGE
3
PRIMARY
SIZE CHECK
1
INTERMEDIATE
SECONDARY
SIZE CHECK
2
INTERMEDIATE
FINE SIZE
REFUSE
COARSE
REFUSE ^ SEPARATION
1
MIDDLE
REFUSE
COARSE PRODUCT
INTERMEDIATE PRODUCT
FINE SIZE PRODUCT
DEWATERING
2
FINISHED PRODUCT
J.J.DAVIS
ASSOCIATES
MANAGEMENT ENGINEERS
Preparation Plant
Modules
3.
RAW COAL
SEPARATION
4.
PRODUCT
DEWATERING WATER
PRODUCT STORAGE
AND SHIPPING
70
-------
has a major effect upon both the size consist and amount of
impurities found in the ROM coal. Where conventional
mining is still used, there will be a high percentage of
large coal lumps, but very little rock. Where mechanical
full-seam mining is used, large pieces of rock may accom-
pany the coal. However, continuous mining machines tend
to create more coal fines.
When the ROM coal is delivered to the preparation
plant site, it is dumped into a surge bin or surge feeder
which controls the feed through the first process module.
Usually the first piece of equipment actually belonging to
the preparation plant that the ROM coal contacts is the
run-of-the-mine scalper.
The ROM scalper is aptly named. It literally scalps
the large pieces of coal and rock off the top of the ROM
coal feed as shown graphically in Figure 5-2. The purpose
of the scalping screen is to size the ROM coal prior to
the primary, or initial, crushing operation. The scalper
helps reduce wear on the primary crusher by allowing the
finer coal and waste material to bypass the crusher; it
improves belt conveyor life by allowing a bed of fine
material to be placed on the belt prior to the larger
lumps, and it allows for the use of a smaller crusher
because of the reduced tonnage which is being fed to it
(see Figure 5-2).
As noted in Chapter 2, the abrasiveness of coal is a
major problem which must be dealt with during the coal
cleaning operation. By eliminating the quantity of fine
material entering the primary breaker and by providing
an impact bed on the conveyor, the ROM scalping screen
greatly assists in prolonging the life of the equipment
involved in the first module.
71
-------
The ROM scalping screen may be fixed or vibrating.
It is usually installed with a slope between 20 and 35
degrees. The slope of the screen dictates its capacity.
An increase in slope of the screen will increase the
velocity of the material passing over the screen and
hence increase its capacity while reducing its efficiency.
The scalping screen is necessarily of very heavy duty
construction enabling it to handle the large tonnages of
coal and rock involved (up to 1500 tph). The screens are
designed with the length twice the width to allow suffi-
cient time for the majority of the smaller material
(usually 6 inches x 0) to fall through the screen openings
onto the conveyor belt. In some cases, lightweight wire
mesh or canvas type material is installed over the screen
flow to slow the flow and allow more of the smaller material
material to fall through the openings. However, since the
oversize (that material passing over the screen) is crushed,
sizing efficiency is of secondary importance.
5.2.1 Fixed ROM Coal Screen
If the scalping screen is fixed, it is generally
referred to as a bar screen or grizzly. This is the
simplest type of screening device found in the coal
preparation plant. The grizzly consists of equally spaced
parallel bars made of cast or forged alloy steel installed
parallel to the feed flow and inclined about 30 degrees.
The grizzly works well with a relatively dry, non-sticky
ROM coal feed.
5.2.2 Vibrating ROM Coal Screen
If the characteristics of the ROM coal are other than
dry and non-sticky, it is usually necessary to install a
vibrating type ROM coal screen. The vibrating ROM coal
screen is usually installed at 25 degrees of slope, and
72
-------
J.J.DAVIS
ASSOC I ATES
ROTARY BREAKER
Figure 5-2 | DCN
-------
heavy-duty construction handles large
volumes of material
high capacity . . . large openings
step arrangement tumbles large lumps
. . . more efficient separation
sectional construction simplifies
maintenance and replacement
184265
Fabricated, fixed-opening bars . . . flared openings
prevent wedging.
Adjustable-step grizzly deck...open-
ings can be changed in the field. Cast-
manganese grizzly bars.
Stepped-deck arrangement with
fabricated bar construction. Baffle-
plate' simplifies chute design and „ V
installation. jj
Figure 5-3
Bar Screens or "Grizzly"
Source: Allis-Chalmers
-------
has a single, perforated plate deck with an impact section
built into the feed end to absorb the impact of the large
pieces of rock and coal. Skid bars to assist the large
pieces in their journey are usually located at the feed
end of the screen and, in some cases, over the entire
screen deck depending upon the size consist and abrasive-
ness of the ROM coal. The deck openings normally range
from 4 to 8 inches with the norm being 8 inches. The
scalper operates with a relatively large stroke (% inch)
because of the large openings. The %-inch stroke will
generally prevent the sticky clay or wet coal from adhering
to and clogging the screen deck. Figure 5-4 depicts a
large vibrating ROM coal screen.
5.3 INITIAL SIZE REDUCTION
There are two primary objectives in crushing coal.
One is to reduce the run-of-the-mine coal to sizes
suitable for cleaning or further reduction; the other is
to reduce the coal to market size. The second step in the
plant feed preparation and raw coal storage module is the
reduction of the ROM coal to make it suitable for cleaning.
There are many types of crushers available, but for
any particular job one specific type of crusher will
probably perform better than any other. The problem is
to determine the one crusher that will give the desired
product in the capacity required at the lowest cost per
ton. The selection of the proper type of crushing facility
depends in part upon the following considerations:
maximum size of the feed coal,
desired capacity,
desired product size,
friability of the coal,
75
-------
Figure 5-4
Vibrating ROM Coal Screens
-------
presence and percentages of rock, sulfur balls,
clay, etc.,
quality of resulting fines and
moisture content of the feed coal.
The maximum input size, the desired product size and the
capacity desired are all engineering characteristics
which are important to equipment selection and are self-
explanatory. The friability and moisture content of the
coal as well as the presence and percentages of rock,
sulfur balls and clay as important criteria for equipment
selection require further discussion.
The friability of the coal not only contributes to
the existing state of the ROM coal, but also denotes the
ease with which the coal may be further reduced, i.e.,
whether the coal may be easily impact reduced or whether
the coal must be crushed in a roll-type or other type of
crusher.
The presence, nature and quality (usually expressed
in percentages) of impurities play an important role in
equipment selection as well. The size, relative hardness
and percentage of rock and sulfur balls when weighed in
relation to the friability of the coal may eliminate one
type of crusher or another, i.e., the rock may aid in
breaking the coal in a Bradford-type rotary breaker and in
forcing the coal through the perforated plates in the
breaker (see Figure 5-2). On the other hand, if a large
percentage of clay is present, and a Bradford-type breaker
is used, the entire perforated plate surface may soon be
plugged and everything entering the breaker will go
directly to the refuse bin. Likewise, if the moisture
content of the ROM coal feed is too high, the wet fines
may plug the perforated plate in the Bradford-type breaker,
or they could literally jam a roll crusher.
77
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5.3.1 Rotary Breaker
The rotary breaker is a heavy trommel screen having
lifters on the inside. The rotary breaker actually serves
a dual purpose in that it both reduces the size of larger
pieces and removes coarse refuse and tramp iron. The use
of this breaker is specifically confined to ROM coal.
The raw coal feed enters at one end and the undersize
quickly passes through the perforations in the outer shell.
The lifters continually raise both coal and refuse on the
ascending side as the shell revolves. The material slides
off the lifters as it reaches the top and falls down onto
the bottom, which after a few revolutions will consist of
the larger pieces of both coal and refuse. Breaking at
this stage is largely due to impact. As the larger pieces
are broken down to smaller sizes, they pass through the
perforated shell, and only those pieces which are not
sufficiently reduced in size pass through the exit end of
the breaker and report to the refuse bin. It is important
that the ROM coal have a suitable friability index to allow
it to be sufficiently broken, while the refuse must be much
harder so that it is not broken, thus permitting its
discharge from the exit (refuse) end of the breaker.
The rotary breaker has several advantages over other
types of breakers (see Section 5.3.2) such as better dust
control (Figure 5-5 and 5-6) and the effective elimination
of large refuse without the loss of carbon. However, as
noted in Section 5.3, there are several limitations to its
use. For example, if the feed contains sticky clay, the
breaker tends to roll the clay into balls which become
pounded into the shell perforations and which will eventu-
ally plug up the breaker (at which time the breaker must
be stopped and cleaned out, effectively curtailing the
operation of the entire plant).
78
-------
Figure 5-5
ROM "Bradford" Breaker
In A Well-Controlled Environment
-* / •
?
,•!
m
^m&^TK
' •". ' v-'-SKi
Figure 5-6
Roll Crusher In
Worst Possible Environment
79
-------
Table 5-1
Sizes and Capacities of Rotary Breakers
Size
Diam. x
Length, Ft
6 x
7 x
9 x
10.5 x
12 x
8
14
17
19
22
Motor,
Approx
Hp
10
15- 20
40- 50
60- 75
100-150
Capacity
Approx .
Thp
75-
125-
275-
500-
1,000-1
150
250
450
750
,5000
Type
of
Coal
Soft
Soft
Medium
Medium,
or nard
Hard
5.3.2 Other ROM Coal Crushers
If the rotary breaker is not utilized for the primary
size reduction operation, pick breakers, hammermill, ring
crushers, jaw crushers, single- and double-roll crushers
and two-stage crushers are common types of crushers that
have been applied to reduce coal to a smaller size for
cleaning purposes.
The usual alternative, however, is a single- or
double-roll crusher (mostly double-roll in modern plants).
Single- and double-roll crushers are manufactured in
various grades, from light-duty models for processing
straight coal to heavy-duty models for handling large
quantities of rock plus coal. Most models have spring-
release mechanisms which enable the crushers to avoid
failure when metal pieces such as miner cutting teeth,
etc., are encountered in the ROM coal feed. Roll-type
crushers break coal by compression (Figures 5-7, 5-8),
80
-------
Figure 5-7
Cross section of double-roll crusher
Source: The Jeffrey Manufacturing Company
Figure 5-8
Crushing Heads
81
-------
i.e., a tooth penetrates a piece of coal and splits it
into smaller pieces in an action that is similar to that
of driving a wedge. The double-roll crusher has several
major advantages when used for initial size reduction: it
produces a very small amount of fines and it is very
adjustable, allowing it to accomodate the varying nature
of ROM coal.
Table 5-2
Capacities of Double-Roll Crushers
Roll Size
Diam. x
Width, In.
Max. Size
of Feed,
In.
Speed of
Rolls
RPM
Product Size, In.
567*
Min.
Motor
HP
24 x 36 6-16
30 x 48 8-20
tip per Ton Crushed
24 x 36 6-18
30 x 48 8-24
Hp per Ton Crushed
24 x 36 6-20
30 x 48 8-24
Hp per Ton Crushed
Soft Bituminous Coal
130 170 200 270 300 15
115 250 330 400 450 25
1/3 1/6 1/6
Medium Hard Bituminous Coal
130 200 260 290 350 15
115 300 390 460 575 25
1/4 1/8 1/8 1/8
Hard Bituminous Coal
130 220 290 350 450 15
115 375 470 550 700 25
1/6 1/10 1/10 1/10
The other types of crushers mentioned are used occa-
sionally as ROM coal crushers, though typically they are
reserved for fine coal crushing. Detailed discussions
82
-------
concerning these crushers, their applicability and the
engineering of fine coal crushing are in Chapter 7.
5.4 RAW COAL STORAGE
The third and usually the final step in Module One
is the storage of the raw coal. This storage function
has become an increasingly important operation in the new,
larger preparation facilities for several reasons:
To limit interruptions of feedstock to the
preparation plant, i.e., to allow the mine and
the plant to function independently with delays
in one not affecting the operation of the other.
To allow controlled feed to the plant which
improves its efficiency—the plant can usually
operate at a much faster rate than the mine and
the plant should not operate much below its
designed operating level to achieve maximum
beneficiation of the coal.
To facilitate blending of various ROM coals to
assist in evening out chemical and physical
variations which may occur if coal from more than
one mine is processed, or if the plant is
servicing a very large mine where the character-
istics of the coal from various places in the
mine vary considerably.
On the other hand, however, several problems are
encountered when storing coal for extended periods of
time, so that common practice in modern preparation plants
is to store only enough raw coal to feed the preparation
plant for a four to eight hour period, thus eliminating
the major problems. A discussion of coal storage problems
appears in detail in Chapter 9.
Storage of the raw coal is generally classified as
open storage, closed storage or a combination of both.
(Figures 5-9 and 5-10 depict open and enclosed storage
facilities.) The selection of the raw coal storage
facility is dependent upon a number of factors. Factors
of primary importance are:
83
-------
Figure 5-9
Open Raw & Clean Coal Storage
Figure 5-10
Enclosed Raw & Clean Coal Storage
4
-------
the plant location in relationship to the mine(s),
the mode of transport of the ROM coal to the
plant site,
the average weather conditions,
the plant capacity, etc.,
the characteristics of the ROM coal and
the capital investment required.
The plant location in relationship to the mine or
mines and the mode of transport of the ROM coal to the
plant site play an important role not only in determining
whether or not the storage function occurs before the
initial size check and size reduction or afterwards as
depicted in Figure 5-1, but also in determining the method
of storage. For example, if the preparation plant is
some distance from the mine and the primary method of
haulage of the ROM coal is rail car, the ROM coal will
usually be held in the rail cars and processed through
the initial size check and size reduction only as needed
for feedstock. If, on the other hand, the coal is trans-
ported to the plant site by conveyor or truck, it is
obvious that major delays will occur in the mining
operation if some storage is not provided at the plant
site.
The characteristics of the ROM coal, coupled with or
independent of the climatic conditions, may dictate the
storage facility. If, for example, there are strong,
prevailing or persistent winds, as found in some
mountainous areas and some parts of the Midwest, it may be
impossible to store coal in open storage without serious
windage losses and serious air pollution generation in the
form of dust. If the coal is very moist and therefore
not as subject to windage, but the climate is very wet,
85
-------
serious water pollution in the form of acid runoff may be
generated by open, uncontained storage facilities.
If the preparation plant capacity is small, 250 to
600 tons per hour (tph), and if the characteristics of the
ROM coal and/or the climate are not too severe, the
initial capital investment required to build a closed
storage facility may simply be beyond the financial reach
of the potential developer.
5.4.1 Open Storage for Raw Coal
Ground storage piles for raw coal are usually conical
or wedge-shaped. The conical pile is the simplest form of
storage and the one most often selected for raw coal
storage. The conical pile is usually flat bottomed with
coal in the dead storage area as shown in Figure 5-11 or
with an earthfill in the shape of a doughnut (Figure 5-12)
which helps to minimize the dead storage area. The ROM
coal is usually delivered to the pile via a stacker
conveyor which may be equipped with a telescopic chute to
minimize dust generation.
Other than the potential pollution problems, the most
critical factor in ground storage is the recovery of as
much coal as possible with a minimum of expense for
equipment and labor. A simple 15,000 ton conical pile
with one center opening to the conveyor gallery will
deliver only 3,000 tons of coal to the plant (this is
called "live" storage). The other 12,000 tons are "dead"
coal and would have to be bulldozed to the feeder opening
to be recovered. By extending the conveyor tunnel across
the diameter of the pile and providing a multi-feeder
arrangement, 50% to 60% of the coal becomes live storage.
The problems of obtaining maximum, open, live
storage of the raw coal is reduced in a few of the very
86
-------
Figure 5-11
Conical Pile and Dead Storage
14'-0" DIA. CONCRETE
STACKER TUBE
IIO'-O" HIGH FROM
TOP OF TUNNEL
12,500-TON LIVE
STORAGE PILE
4 RECLAIM FEEDERS
CAPACITY—750 TPH EACH
RECLAIM BELT CONVEYOR
CAPACITY—2500 TPH
Figure 5-12
Conical Pile with Earth Fill
to Eliminate Dead Storage
'•
-------
large preparation plants by using wedge-shaped piles
ranging from 25,000 tons to 100,000 tons of total storage.
However, this type of raw coal storage is rare and shall,
therefore, be addressed in detail in Chapter 9 as a clean
coal storage technique.
5.4.2 Closed Storage for Raw Coal
Storing raw coal in enclosed bins provides protection
against the elements, minimizes the potential for airborne
pollutants and provides for near 100% live storage.
Various types of enclosed bins and silos are available.
The majority of the larger capacity bins are cylindrical
in shape and usually are made of steel or concrete.
5.4.2.1 Steel Storage Bins The typical steel raw
coal storage bins have between 1000 and 1500 ton capacities,
although steel bins up to 60 feet in diameter holding
approximately 4000 tons have been built and bins up to 100
feet in diameter with capacities of 10,000 tons have been
proposed. Steel storage bins have sloping bottoms con-
structed of steel plate which makes possible the gravity
withdrawal of all the raw coal contained within. In
preparation facilities that clean coal for more than one
company, the use of several of these steel storage bins
allows for the segregation of the individual property.
In other cases where the coal from varying sections within
a mine or from various mines have significantly different
characteristics, several steel storage bins may be required
to assure proper blending of the coals to obtain a uniform
feedstock for the plant.
Low capacity steel storage bins are less expensive to
construct than similar concrete silos; however, their
capacity per diameter (floor space consumed) and maintenance
problems (especially when corrosive high-sulfur,
88
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high-moisture or highly abrasive coals are handled)
minimize their use in new preparation facilities.
5.4.2.2 Concrete Silos—With the advent of new
concrete construction technology and the increasing size
of raw coal storage facilities (larger than 1500 tons), it
is now more economical (when the costs are expressed in
dollars per ton of storage capacity) to construct storage
facilities of concrete. Additionally, when storage is
expressed in terms of floor space utiliziation, the
concrete silo is usually superior.
A 60 foot diameter steel bin typically has a capacity
of about 4000 tons, while a 70 foot diameter concrete silo
will have a capacity of up to 10,000 tons.
As with the steel bins, the concrete silos provide
nearly 100% live storage of raw coal and excellent protec-
tion from the elements plus they eliminate all the
pollution problems associated with coal storage. The
details of a concrete silo are shown in Figure 5-13.
89
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MANHOLE \ INTAKE OPENING
BAR JOIST
Details of a
Concrete Silo
90
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REFERENCES AND/OR ADDITIONAL READING
Bituminous Coal Research, Inc., "An Evaluation of Coal Cleaning
Processes and Techniques for Removing Pyritic Sulfur from Fine
Coal", BCR Report L-339, September 1969, BCR Report L-362, February
1970, BCR Report L-404, April 1971, BCR Report L-464, April 1972
Charmbury, H.B., "Mineral Preparation Notebook", Pennsylvania State
University
Coal Age, "Coal Preparation and Unit-Train Loading", July 1972
Coal Age, "The Coming Surge in Coal Preparation", January 1976
Coal Age, "U.S. Steel Coal Preparation", Model Mining Issue,
October 1973
Coal Research Bureau, "Underground Coal Mining Methods to Abate
Water Pollution", West Virginia University, 1970
Cooper, Donald K., "Coal Preparation - 1974", Mining Congress Journal,
February 1975
Daub, Charles H., "The Oneida Plant", Mining Congress Journal, July 1974
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Deurbrouck, A.., "Survey of Sulfur Reduction in Appalachian Region
Coals by Stage Crushing", U.S. Bureau of Mines Report of Investi-
gations #8282
Felde, Stuart R., "Large Front-End Loaders in Western Coal", American
Mining Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Flygt Corporation, "Mine Dewatering Submersible Pumps", Brochure, 1975
Foreman, William'E., "Impact of Higher Ecological Costs and Benefits
on Surface Mining", American Mining Congress Coal Show, Detroit,
Michigan, May 1976
Goodridge, Edward R., "Duquesne Light Maximizes Coal Recovery at its
Warwick Plant", Coal Age, November 1974
91
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Ivanov-, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracity in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Jeffrey Mining Machine Co., "Jeffrey Mining Machine Company: Manu-
facturers Information", Columbus, Ohio
Jenkinson, D.C., "Some New Coal Preparation Developments in the United
Kingdom", National Coal Board Bulletin M4-B148
Katen, Ken P.; Palowitch, Eugene R., "Shortwall vs Conventional Systems",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Kester, W.M., "Magnetic Demineralization of Pulverized Coal"
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
Korol, Dionizy, "Influence of Hydraulic Getting on Mechanical Coal
Preparation", Przeglad Gorniczy, Year 12 #12, December 1956
(National Coal Board Translation Section)
Kuti, Joe, "Longwall vs. Shortwall Systems", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania, May 1975
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Llewellyn, Robert L., "Coal Preparation", Elements of Practical Coal
Mining, Seeley W. Mudd Series, American Institute of Mining,
Metallurgical and Petroleum Engineering, Inc., New York, 1968
Lotz, Charles W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Manwaring, L.G., "Coarse Coal Cleaning at Monterey No. 1 Preparation
Plant", Mining Congress Journal, March 1972
McNally-Pittsburg Manufacturing Corporation, "Coal Cleaning Plant
Prototype Plant Design Drawings", Department of Health, Education and
Welfare Contract 22-68-59
McNally-Pittsburg Manufacturing Corporation, "Coal Preparation
Manual #572", Extensive Analysis on McNally Pittsburg Coal Cleaning
Technology
92
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
National Coal Board, "Hydraulic Transport of Coal at Woodend Colliery",
September 1961 . .
Nirtsiyev, "Hydraulic Extraction of Coal in the Donetz Basin Izdatel
'Stvo "NEDRA", Moscow 1969 (Translated by Terraspace)
Nunenkamp, David C., "Survey of Coal Preparation Techniques for
Hydraulically Mined Coal", Published for Terraspace Inc., July 1976
Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
Desulfurization", Chicago, Illinois, October 1965
Protopapas, Panayotis, "A Report in Mineral Processing", Department of
Applied Earth Sciences, Stanford University, 1973
R.M. Wilson Company, Inc., "Mine Productivity Systems and Equipment",
Catalog #288-P
Roberts & Schaefer Company, "Manufacturers Information Booklets",
Chicago, Illinois
Roberts & Schaefer Company, "Design & Cost Analysis Study for Proto-
type Coal Cleaning Plant", August 1969
Roberts & Schaefer Company, "Research Program for the Prototype Coal
Cleaning Plant", January 1973
Stefanko, Robert; Ramani, R.V.; Chopra, Ish Kumar, "The Influence of
Mining Techniques on Size Consist and Washability Characteristics
of Coal", National Technical Information Service, Springfield,
Virginia, August 1973
Tieman, John W., "Chemistry of Coal", Elements of Practical Coal Mining,
Seeley W. Mudd Series, American Institute of Mining, Metallurgical
and Petroleum Engineering, Inc., New York 1968
Wemco Division, "Manufacturer's Catalog", Envirotech Corporation,
Sacramento, California, 1974
93
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THIS PAGE INTENTIONALLY LEFT BLANK
94
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6. RAW COAL SIZING
6.1 OVERVIEW
There are three general reasons for sizing operations
in commercial coal preparation practices today. They are:
to separate raw coal into various sizes to feed
different types of cleaning units,
to assist in the recovery of fines in the
original feed and in the recovery of fines
produced during the processing operations and
to assist in the recovery of solids used to
control the specific gravity in cleaning units.
The raw coal sizing module includes primary and secondary
size separations with the resultant material being raw
coal feed that is distributed to three separate processing
circuits—coarse, intermediate and fine. This module is
i
shown in Figure 6-1.
Most coal cleaning processes require that for maximum
efficiency the coarse and fine sizes be cleaned separately.
Raw coal is separated by size (sized) in a wet or a dry
screening operation with the choice being dependent upon
the method of additional processing. It must be noted,
however, that screens are used many times during the coal
cleaning process and that this section of the manual
addresses only the initial sizing process. An example of
the varying screen uses is given in the following scenario
(numbers refer to details shown in Figure 6-2):
95
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COARSE
REFUSE
UNDER
OVER
1.
PLANT FEED
PREPARATION
SIZE REDUCTION
2
RUN OF MINE STORAGE
3
2.
RAW COAL
SIZING
INTERMEDIATE
SECONDARY
"SIZE CHEC'tC.,
. 2
MIDDLE
REFUSED—^SEPARATION
2
3.
RAW COAL
SEPARATION
PRODUCT WATER
DEWATERING WATER
5.
PRODUCT STORAGE
AND SHIPPING
J.J.DAVIS
ASSOCIATES
MANAGEMENT ENGINEERS
Preparation Plant
Modules
Figure 4-2 I DCN
96
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The run-of-the-mine coal is fed to the scalping screen
with the oversize from the scalper going to a crusher
(1). Material going through the deck of the scalper
is combined with the crusher discharge and fed to a
raw coal sizing screen (2). The fine-size (slack)
coal which goes through the raw coal sizing screen is
either loaded out as a finished product or goes to
module three for further processing (3). The material
over the deck of the raw coal sizing screen is fed to
a prewet screen prior to being fed to the coarse coal
circuit (4). Float material from the coarse coal
circuit is fed to a drain and rise screen which may be
followed by a dewatering screen and additional sizing
screens (5). The sink material from the coarse coal
circuit is fed to a drain and rise screen with the
refuse material being fed either to a dewatering
screen or directly into a refuse bin (6).
6.2 NOTES ON SCREENING
The fundamental function of screening is to pass the
undersized coal particles through the screen surface and to
reject, i.e., pass over the screen surface, the oversized
coal particles. The individual particles should be
brought to the openings of the screen and presented to
those openings at a minimum velocity and in such a manner
that the passage of undersized particles will not be
hindered or prevented by rebound from the edges or walls
of the opening. If every particle of undersized coal could
be brought to the screen openings individually, at substan-
tially zero velocity, in a direction perpendicular to the
plane of the opening, with the center of the particles
projected cross section in line with the center of the
last opening, and if the screening surface had no thickness,
every undersized particle would pass through the Screen.
But tonnage requirements prohibit individual and low
velocity presentation of coal particles, while mechanical
considerations prevent perpendicular presentations of the
particles to the openings and the use of very thin
screening surfaces.
97
-------
vD
CO
J.J.DAVIS
ASSOCIATES
-------
In reality, then, the particles on the screening
surface are crowded and continually interfering with each
other at the openings; they are presented at high speed,
nearly parallel to the screen surface with their most
projected cross section in line with the center of the
openings. As a direct result, many of the undersized
particles are prevented for a considerable time from
passing through the openings either due to their speed of
travel or their angle of attack, and many, in fact, are
rejected entirely as oversized.
Most of the screening principles in past practice have
assumed that the only force operating on a coal particle
on a screen was the vertical component of gravity.
Although in modern screening practics the vertical compo-
nent of gravity is the principle force involved, other
forces are brought into play. This is accomplished by:
sloping the screens so that the horizontal
component of the particle's momentum becomes
the principal force affecting the approach of
the particle to the opening and
by shaking or vibrating the entire screen or its
screening medium in such a way as to contribute
additional forces to the particles. These
forces aid in the stratification of particles
above the screen and influence the angle,
velocity and direction of the particles
approaching the openings. The forces also give
additional energy for the passage of smaller-
than-opening particles or for the rejection for
a later trial at passage of near-size and
larger particles.
Thus, screening is not only a single static process
of particles dropping through an opening under the influ-
ence of gravity, but a dynamic one in which each particle
is aided in reaching a favorable position over, and given
enough force to go through, an opening, or to be rejected
for another try with different orientation at another
opening.
99
-------
In commercial sizing or screening, two basic
processes take place:
stratification—the process or phenomenon
whereby the larger sized particles of coal rise
to the top of the bed being shaken or vibrated
while the smaller sized particles sift through
the voids and find their way to the bottom of
the bed, and
separation—the process of particles presenting
themselves to the openings and being rejected
if larger than the opening or passed through if
smaller.
Stratification of particles helps screening by the
vibration action which forces the finer sizes through the
screen wire while the coarser sizes, rising to the top,
add force to push the small pieces through the opening.
It should be noted that stratification is continually
upset or nonexistent in a rotary type or trommel screen.
This offers some insight for the recognized lesser
efficiency of the rotary screen versus a vibrating screen.
On the other hand, the relative gentleness of shaker
screens effect little stratification and they are conse-
quently fed very thin beds of coal which also accounts for
their relative inefficiency, in the sense of the ability
of equal screening areas of various types to remove the
undersized coal from a given feed.
In the separation process it is important to recognize
that coal particles are of an infinite number of sizes and
shapes, and it is required that the near-sized particles
have the opportunity to present themselves to the opening
in many different positions to insure their passage. The
ratio of feed to a given screen size directly affects this
separation function. Note that for low tonnages (tph of
feed) the efficiency actually increases with increased feed,
This is due to the fact that a bed of oversize coal
100
-------
particles on top of the marginal sized coal particles
prevents the marginal sized particles from bouncing exces-
sively, thereby increasing their number of trials to pass
through the openings. This axiom is true up to a point.
After the optimum is reached, the efficiency rapidly drops
off as the feed increases simply due to the fact that the
screen is not large enough (length vs width vs bed depth)
to allow for the proper stratification which would ensure
the necessary separation.
Figure 6-3 illustrates the stratification and
separation of the coal particles as they move across a
screening surface.
^**PJ
k c
SCREEN LENQTH
Figure 6-3
Representation of Screening
Action in the Longitudinal Direction
In Figure 6-3 the rise between "a" and "b" shows the effect
of stratification taking place. The area "a" to "c" is
often referred to as the area of saturation screening where
particles up to about 75 percent of aperture size are
crowding through the screen deck. In the area from "c" to
"d" the final process of fit and pass or reject takes place.
101
-------
The thickness of the coal bed on the screen deck is
important to develop the ultimate screening efficiency.
The speed of travel of the material on the screen deck
determines the appropriate thickness. In addition, the
slope or inclination of the screen affects not only the
capacity in binding which is a term describing the lodging
of pieces of coal or slate resulting in a decrease in open
area for the particles to pass through the screen, but
determines the rate of travel of the particles across the
screen surface, which determines its thickness, etc.
Among the other factors affecting screening efficiency,
the choice of the proper screening media is extremely
important. In choosing the proper media, consideration
must be given to the desired product size, the load on
the screen and the metal that is most economical for the
particular screening problems encountered.
The types of screening media now most widely used in
coal preparation are:
perforated or punched plate
woven wire cloth and
profile wire screens.
Perforated screens can be obtained in a variety of
opening shapes and sizes in a variety of metals: Mild
steel for normal applications, high carbon steel, A R
steels and other trade alloys for extremely abrasive
applications; and stainless steel and manganese bronze
where corrosion is severe and where smaller openings are
needed. Additionally, rubber, ceramic and synthetic
coating on mild steel plates have proven successful on
many extremely abrasive and corrosive applications. As
Figure 6-4 illustrates, the perforations may be of various
shapes and sizes. Additionally, the openings may be
102
-------
staggered to give the coal particles a better chance to
find an opening through which they may pass.
SQUARE PERFORATIONS
STRAIGHT UNES
• • • v
HEXAGON PERFORATIONS ,
STAGGERED J_
SLOTS
SIDE STAGGER
SLOTS
STRAIGHT UNES
Figure 6-4
Standard Types of Perforated Screen
The percent of open screening area varies directly
with the screening capacity and efficiency, but varies
inversely with the load carrying capacity and the antici-
pated life of the screen. Woven wire cloth generally is
used oh vibrating screens where a maximum percent of open
area is desired. The wire cloth in this application may
be woven with wires of various diameters ranging from .02
inches to 1 inch. As with the perforated plate, special
surfaces of rubber, enamel, etc., may be applied. In
choosing the proper wire cloth, two factors are most
important: sizing accuracy and screen life. The rectangu-
lar and slotted weaves provide more screening capacity
than the square weave and are generally more efficient in
screening coal, but less accurate in sizing. The woven
103
-------
wire cloth is available in all standard mesh openings and
in space openings 1/8" to 10" (mesh denotes the number of
openings per lineal inch and space denotes the actual
dimension of the clear openings).
The final type of screening surface usually
encountered on coal processing screens in the profile rod.
The term profile is applied to this type of screening
medium because the screen surface rods have a definite
profile (cross section). The most common profile rods are
shown in Figure 6-5.
.30"
32 B
Tri-Rod
lite 19°
Ito-Rod
2 to 5*
Grizzly-Rod
Round Rod
Figure 6-5
Common Types of Profile Rod Screens
Today, with the improved metal and design, there are
many sloping vibrating units to choose from. The main
problem is to establish the correct slope angle and screen
area needed to accomplish the desired separation.
Vibrating screens (Figure 6-6) are the mainstay of
today's coal preparation plants. They find application in
all phases of coal processing—from scalping of raw coal
to dewatering of extremely fine sizes of coal or refuse.
The two types most commonly found in preparation plants
104
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6.3 APPLICATION
6.3.1 The Raw Coal Screen
Raw coal separations are made at openings from 3/4"
to 6 mesh with most of the separations occurring in the
range of 3/16" to 5/16".
The raw coal screen is usually a single deck or
double deck, two-bearing, circle-throw, inclined screen.
The purpose of the top deck of the double deck unit is to
relieve the load on the lower deck and to increase the
overall capacity of the screen. Either wet or dry
screening is utilized with the majority of the preparation
plants being designed for wet screening. The duty of the
raw coal screen is to remove fines—normally minus 3/16"
in size—prior to the coarse coal sysle. The fines would
upset the specific gravity of the bath if they were
allowed to enter it, and they may be loaded out as slack
coal or transferred to another part of the plant for
further processing either in the intermediate coal circuit
or in the fine coal circuit. (Refer to Figure 6-1.)
When dry screening raw coal, the surface moisture and
the amount of clay present are important considerations
and must be known. The major effect of these factors is
the plugging of the screen surface with the secondary
effect being the inefficient screening due to fine parti-
cles sticking to the coarse size particles, and riding
over the screens with the oversized materials. The amount
of moisture and clay which will produce binding is
difficult to establish since it varies with the type of
coal, the size of the feed and the screening surfaces used.
Vibrating screens for dry screening raw coal are
selected by using standard screen selection formulae,
except for the Pocohontas seam coals which are sized from
107
-------
a specific table. (These standard screen selection
formulae may be found in The Screening Bible, publication
PM 1.1 of the Allis-Chalmers Crushing and Screening Equip-
ment Division.) Because of the variables in raw coal, it
may be advisable to increase the calculated screen area by
20 percent to insure an acceptable installation.
Pocohontas seam coal is very friable and for this
reason is much finer as it comes from the mine. This
results in a greater amount of undersized particles to be
removed and the screen areas calculated by the general
formulae tend to be misleading. Screens handling Pocohon-
tas coal are selected on the basis of the amount of coal
passing through a square foot of the available screen area
rather than on the total feed to a deck.
If only one separation is required of the raw coal
screen and if the feed has a top size of about 4" to 7",
a single deck screen can be used with wire cloth having
the long dimension of screen openings parallel to the
particle flow. This method has the advantage of using the
larger sizes of coal to scour the cloth in order to
prevent binding and allowing higher moisture coals to be
screen dried. The disadvantages are the inaccurate sizing
obtained with the rectangular opening and the increased
wire cloth damage due to handling large feeds. The
screening capacity of a single decked screen with
rectangular openings in tons per square foot is high, but
the single decked screens must be larger than double deck
screens because the entire load is carried on one deck
instead of being split to two decks. Manufacturer's tables
give the recommended screening surface when dry screening
raw coal on a single deck screen using rectangular openings
with a maximum of 5 percent, surface moisture in the screen
feed. Other tables give the maximum surface moisture
108
-------
permissible in the feed when dry screening raw coal. If
the moisture exceeds these amounts, binding or plugging
will probably occur caused by the fine coal adhering to
the screen wires or by wedge shaped particles lodging in
the openings. Several methods to prevent binding may be
used, including: increasing the amplitude or speed,
changing the screening surface, using drag chains or by
using a heated deck.
6.3.2 Pre-Wetting Screens
The raw coal may be screened either wet or dry
depending upon the ultimate treatment of the fine fractions
of the feed and the moisture content of the feed. If the
feed preparation (raw coal screening) was performed dry,
there may still be some fine coal particles adhering to
the oversized coal. These must be removed so the fine
coal will not interfere with the subsequent processing.
If the surface moisture of the coal is high enough to make
dry screening impractical, wet screening with sprays must
be used. If the coarse coal is to be cleaned by the
heavy media process, it is essential that the coal enter
the vessel at a constant moisture content in order to
maintain the specific gravity of the separating medium.
Screens for wet sizing are selected by using the standard
screen formulae. The pre-wet screening process is shown
in Figure 6-7.
The amount of water used on pre-wetting screens
depends upon the size of the coal and the amount of the
undersized material to be removed. Three to six gallons
per minute (GPM) of spray water per ton at a minimum of
30 psi is recommended for screening on wet screens. In
addition, the feed should enter the screen in a soaked
condition. This is usually accomplished by adding water
109
-------
Figure 6-7
Pre-wet Screening Operation
to feed in the chute ahead of the screen. More water per
ton of coal must be used on the finer separations and on
double decked screens than on larger separations and on
single decked screens. Usually two or more rows of sprays
are used.
Capacity of pre-wetting screens is determined by the
maximum depth of the material on the screen deck that can
be successfully rinsed by water sprays. The maximum
material depth will vary with the feed size since the
smaller sizes are more difficult to rinse. Pre-wetting
screens are usually selected so that the bed depth does
not exceed two or three times the top size of the coal.
Approximately 6 to 8 inches of coal is considered the
maximum depth that can be pre-wetted completely.
no
-------
REFERENCES AND/OR ADDITIONAL READING
Allis-Chalmers, "Screening Machinery", Engineering Bulletin on
Selection of Vibrating Screens
Bituminous Coal Research, Inc., "An Evaluation of Coal Cleaning
Processes and Techniques for Removing Pyritic Sulfur from Fine
Coal", BCR Report L-339, September 1969, BCR Report L-362, February
1970, BCR Report L-404, April 1971, BCR Report L-464, April 1972
Charmbury, H.B., "Mineral Preparation Notebook", Pennsylvania State
University
Coal Age, "Coal Preparation and Unit-Train Loading", July 1972
Coal Age, "The Coming Surge in Coal Preparation", January 1976
Coal Age, "Consol Preparation Confirms Coal Quality", October 1972
Coal Age, "Peabody Pioneers in Coal Handling & Preparation", Model
Mining Issue, October 1971
Coal Age, "U.S. Steel Coal Preparation", Model Mining Issue,
October 1973
Cooper, Donald K., "Coal Preparation - 1974", Mining Congress Journal,
February 1975
Daub, Charles H., "The Oneida Plant", Mining Congress Journal* July 1974
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Deurbrouck, A.W., "Survey of Sulfur Reduction in Appalachian Region
Coals by Stage Crushing", U.S. Bureau of Mines Report of Investi-
gations #8282
Kokunin, A.V.; Onika, D.G., "Hydraulic Underground Mining", Translated
for Branch of Bituminous Coal Research, Division of Bituminous Coal,
U.S. Bureau of Mines
Felde, Stuart R., "Large Front-End Loaders in Western Coal", American
Mining Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
111
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Flygt Corporation, "Mine Dewatering Submersible Pumps", Brochure, 1975
Foreman, William E., "Impact of Higher Ecological Costs and Benefits
on Surface Mining", American Mining Congress Coal Show, Detroit,
Michigan, May 1976
Goodridge, Edward R., "Duquesne Light Maximizes Coal Recovery at its
Warwick Plant", Coal Age, November 1974
Gospodarka, Gornictwa, "Possibilities of Mechanical Preparation
Underground", 1956 No. 4
Humboldt-Wedag, "Manufacturers Brochures", Cologne, Germany
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiaiton of Coal and Anthracity in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Jeffrey Mining Machine Co., "Jeffrey Mining Machine Company: Manu-
facturers Information", Columbus, Ohio
Jenkinson, D.C., "Some New Coal Preparation Developments in the United
Kingdom", National Coal Board Bulletin M4-B148
Johnson Division, UOP Company, "Brochure - 1975"
Kester, W.M., "Magnetic Demineralization of Pulverized Coal"
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
Kollodiy, K.K.; Borodulin, V.A.; Nazarov, P.G., "Processing of Coal
Mined by the Hydraulic Method", Ugol #9, 1974 (Translated by
Terraspace)
Korol, Dionizy, "Influence of Hydraulic Getting on Mechanical Coal
Preparation", Przeglad Gorniczy, Year 12 #12, December 1956
(National Coal Board Translation Section)
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Llewellyn, Robert L., "Coal Preparation", Elements of Practical Coal
Mining, Seeley W. Mudd Series, American Institute of Mining,
Metallurgical and Petroleum Engineering, Inc., New York, 1968
112
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Lotz, Charles W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Lovell, Harold L., "Sulfur Reduction Technologies in Coals by Mechani-
cal Beneficiation (3d Draft)", Commerce Technical Advisory Board
Panel on SO Control Technologies, March 1975
Manwaring, L.G., "Coarse Coal Cleaning at Monterey No. 1 Preparation
Plant", Mining Congress Journal, March 1972
Mathur, S.P., "Hydraulic Mining of Coal", Journal of Mines, Metals and
Fuels, May 1972
McNally-Pittsburg Manufacturing Corporation, "Coal Cleaning Plant
Prototype Plant Design Drawings", Department of Health, Education and
Welfare Contract 22-68-59
McNally-Pittsburg Manufacturing Corporation, "Coal Preparation
Manual #572", Extensive Analysis on McNally Pittsburg Coal Cleaning
Technology
Mengelers, J.; Absil, J.H., "Cleaning Coal to Zero in Heavy Medium
Cyclones", Coal Mining and Processing, May 1976
Nirtsiyev, "Hydraulic Extraction of Coal in the Donetz Basin Izdatel
'Stvo "NEDRA", Moscow 1969 (Translated by Terraspace)
Nunenkamp, David C., "Survey of Coal Preparation Techniques for
Hydraulically Mined Coal", Published for Terraspace Inc., July 1976
Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
Desulfurization", Chicago, Illinois, October 1965
Protopapas, Panayotis, "A Report in Mineral Processing", Department of
Applied Earth Sciences, Stanford University, 1973
Protsenko, I.A., "The Technology of Beneficiation andDewatering of
Coal Mined by the Hydraulic Method", Questions Regarding the Hydraulic
Production of Coal, Trudy VNIIGidrougol, Vol. XI, 1967 (Translated
by Terraspace)
R.M. Wilson Comapny, Inc., "Mine Productivity Systems and Equipment",
Catalog #288-P
Roberts & Schaefer Company Manufacturers Information Booklets",
Chicago, Illinois
113
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Roberts & Schaefer Company, "Design & Cost Analysis Study for Proto-
type Coal Cleaning Plant", August 1969
Roberts & Schaefer Company, "Material Handling and Processing Facilities
for the Mining Industry", 1974
Roberts & Schaefer Company, "Research Program for the Prototype Coal
Cleaning Plant", January 1973
Sal'nikov, V.R., "Experience and Outlook Regarding the Application of
Hydromechanization of Steep Seams in the Kuzbass", UGOL #7, 1973
Schuhmann, Reinhardt, Jr., "Metallurgical Engineering, Vol. I,
Engineering Principle", Addison-Westey Publishing Company, Inc.,
Reading, Massachusetts, 1952, p. 84
Sokaski, M; Sands, P.F.; Geer, M.R., "Use of a Sieve Bend and a
Scalping Deck With a Vibrating Screen in Dewatering and Draining
Dense Medium From Fine Coal", U.S0 Bureau of Mines Report of
Investigations #6311
Stefanko, Robert; Ramani, R.V.; Chopra, Ish Kumar, "The Influence of
Mining Techniques on Size Consist and Washability Characteristics
of Coal", National Technical Information Service, Springfield,
Birginia, August 1973
Tieman, John W., "Chemistry of Coal", Elements of Practical Coal Mining,
Seeley W. Mudd Series, American Institute of Mining, Metallurgical
and Petroleum Engineering, Inc., New York 1968
Tyler, C.E., "Testing Sieves & Their Uses", Combustion Engineering, Inc.
Handbook #53, 1973 Edition
Weraco Division, "Manufacturer's Catalog", Envirotech Corporation,
Sacramento, California, 1974
Yancey, J.F., "Determination of Shapes of Particles in Coal and Their
Influence on Treatment of Coal by Tables", AIME Translation, 94
114
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7. RAW COAL SEPARATION
7.1 OVERVIEW
The overall economics of a coal preparation plant
are governed by a number of interdependent parameters
which individually and collectively affect the final
results. The most significant of these factors is the
amount of salable clean coal, or plant yield. The plant
yield is dependent upon the raw coal separation module.
The raw coal separation module (module #5) highlighted in
Figure 7-1 is defined as those portions of the preparation
plant processes which either mechanically or hydraulically
separate the coal from its associated impurities.
Although by this definition moisture is considered an
impurity, moisture will be specifically eliminated from
discussion under module #3 and addressed in detail as a
separate entity, "Module #4 Product Dewatering and Drying"
in Chapter 8.
Once the theoretical yield for a particular coal has
been determined from washability studies (see Chapter 11),
the optimum return is achieved by approaching this
theoretical yield as nearly as possible in a practical
commercial operation. As indicated in Figure 7-1, raw
coal separation is the largest process module and is
extremely variable in regard to the number of possible
combinations of equipment, the influence of the specific
coals, the refuse/by-product generation, etc. Optimiza-
tion, therefore, depends upon the combination of several
115
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1.
PLANT FEED
PREPARATION
2.
RAW COAL
SIZING
3.
RAW COAL
SEPARATION
0
4.
PRODUCT
DEWATERING WATER
FINE SIZE PRODUCT
5.
PRODUCT STORAGE
AND SHIPPING
J.J.DAVIS
ASSOCIATES
MAfMAI .tMtlNJI F N C • i IM t. t tV S
Preparation Plant
Modules
Figure 4-2 TDON
116
-------
processes to produce the ideal combination of the coarse
and fine coal components which will result in the maximum
yield of clean coal.
7.2 SPECIFIC GRAVITY SEPARATION
In the mechanical coal cleaning process, all of the
commercially acceptable techniques to remove ash, sulfer
and other impurities from the ROM coal are based upon
specific gravity separation of the coal from its associated
impurities with the exception of froth flotation (see
7.3.6). An understanding of the mechanism of specific
gravity separation is essential to an understanding of the
coal cleaning process. An ideal cleaning process is one in
which all coal lighter than a pre-determined density is
recovered in a washed product and all the heavier material
is eliminated in the refuse. There is no mechanical coal
cleaning process that can achieve this goal; however,
some processes approach the goal more closely than others.
The factors affecting the performance of these varying
equipment configurations are discussed in the paragraphs
which follow.
Coal usually of low specific gravity and the associated
impurities of high specific gravity report largely to their
proper product, washed coal and refuse respectively. How-
ever, as the specific gravity of separation is approached,
the portions of misplaced material (that portion of material
reporting to an improper product, coal in refuse or refuse
in coal) increases rapidly. Figure 7-2 illustrates the
impact of misplaced material as the specific gravity of
separation is reached. The lower curve (B) is characteristic
of the relatively sharp separation that can be achieved in
dense-medium cleaning units (see 7.3 Methodologies). The
upper curve (A) is
117
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characteristic of Baum jig cleaning units (see Section 7.3
Methodologies). With either type of cleaning unit, a high
proportion of the near gravity material (the material just
lighter or just heavier than the density of separation)
reports to the wrong product.
BAUM JIG
DENSE MEDIUM VESSEL
,, /CLEAN COAL]
f°\ RAW COAL /
IN THE REFUSE
% REFUSE IN THE
CLEAN COAL
-0.4 -0.2 0.0 +0.2 +0.4 +0.6 +0.8
SPECIFIC GRAVITY DIFFERENCE
(SP. GR. OF SEPARATION-SPECIFIC GRAVITY OF MATERIAL IN THE FEED)
Figure 7-2
Misplaced Material in the Separation Products
The mechanics of the separation process is a complex
physical process and one which to some extent has not been
fully defined. Particle size and shape affect the degree
of separation. The finer sizes of coal are treated less
effectively than the coarser sizes in all cleaning
processes. Figure 7-3 shows the unique distribution curves
for a .particular coal when both the coarse and fine
118
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100
90
80
70
a
UJ
60
4
O
o
4
50
40
u
o
-------
certain types of washers require a rather small range in
the size of the feed they will tolerate. Examples include
the mechanical jig and most classifier-type units. How-
ever, even where the washer is designed to take all coal
from 6" down to 0, some compromise must be made in the
sharpness of separation. Consequently, if tonnage is
fairly high and a sharp separation is desired throughout
the full size range, several separate cleaning systems
must be installed for the coarse and fine fractions, e.g.,
one system for 6" x 3/4", one system for 3/4" x 0" and
one for the ultra-fines, 48-mesh x 0.
Research conducted by the U.S. Bureau of Mines indi-
cates that the shape of the particles also affects the
refuse sizes. The size and shape of a particle as well
as its density determine its path in a moving fluid: flat,
tabluar pieces are considerable more difficult to remove
than are particles of more nearly cubic or spherical shape
due primarily to the media's resistance to the particles
Which must pass through it, and to the fact that a mass of
particles are being processed simultaneously which
interferes with the free movement of particles within
the medium. Other factors influencing the distribution
curve include throughput, the mechanical condition of the
cleaning unit, and the adequacy of the control of the
cleaning unit and the feed rates.
The ideal condition for separation of coal with the
heavier specific gravity refuse is a still bath of the
proper specific gravity. The proper specific gravity may
be achieved through true or artificial solutions, and the
more precisely the specific gravity of the solution is
controlled, the sharper the resulting separation. A
number of systems have been developed to create the actual
or artificial specific gravities needed to effect the
separation which will be discussed in the next section.
120
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7.3 METHODOLOGIES
The methodologies of raw coal separation are varied
and numerous. Figure 7-1 points out that the raw coal
separation module has been broken down into three distinct
process areas: coarse, intermediate and fine size coal
cleaning circuits. One example of each of these areas is
identified in Figure 7-4. For the purposes of this
discussion, each of these categories will be addressed
individually. It must be remembered that in reality there
is considerable" overlap among the systems.
The profitable operation of a coal preparation plant
under today's stringent product standards and ever-rising
labor and equipment costs requires that the preparation
engineer continually strive for maximum recovery of sala-
ble coal. Reliable performance data are a prerequisite to
the design of the new plant or to the expansion of existing
facilities, and they serve as a yardstick with which the
engineer can measure the performance of the plant. Having
such data and a washability analysis of the raw coal, the
preparation engineer can make a rational choice of cleaning
equipment. Utilizing this data, the engineer may address
each of the raw coal fractions (coarse, intermediate and
fine) with the two main tools of coal preparation: Dense
Medium Separation and Hydraulic Separation.
7.3.1 Dense Medium Separation of Coarse Coal
To meet the current product quality requirements,
dense media vessels are cleaning an ever-increasing
percentage of the total clean coal prepared. Today
approximately 40% of the mechanically cleaned coal is
washed through dense media equipment. Dense media cleaning
is based on a rather simple principle. Just as small
pieces of wood float while sand sinks in water, coal will
121
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to
NJ
J.J.DAVIS
ASSOCIATES
Examples of
Coal cleaning
Equipment
Figure 7-4 | DCN
COARSE
SIZE
COH
WASHER
HNE SIZE
COAL WASHER I
p 1 ' IE1HIT F
liifH __J j mi" iiiiinii cms
55*&>rti T T T T T
-------
float while refuse sinks when placed in a medium that has
a specific gravity which is between the specific gravities
of the coal and refuse.
Commercial application of the dense medium process is
a practical extension of the familiar laboratory float-and-
sink test (see Chapter 11), which is used as a standard
for 100% efficiency gravimetric separation. Commercial
plants do not exactly duplicate laboratory float-and-sink
separations for the following reasons: suspensions, rather
than true liquids, usually are used as a separating medium;
the introduction of feed and removal of the float-and-sink
introduce disturbances in the separating medium; agitation,
or upward currents in the vessel, normally is required to
keep the separating medium in suspension; and the practical
need for high throughput does not allow sufficient reten-
tion time for perfectly separating near-gravity material.
Theoretically, any size particle can be treated by
dense medium processes; practically, however, sizes from
6" to V are normally cleaned in the coarse coal circuit.
The benefits of washing finer than V material are usually
offset by the increased medium loss and reduced cleaning
capacity. The ideal separating medium would be a true
liquid having the following properties: low in cost,
miscible with water, capable of adjustment over a wide
range of specific gravities, stable, non-toxic, non-
corrosive and low in viscosity. Although no ideal medium
exists, a variety of dense media have been developed, but
only the suspensions of magnetite and sand have found
widespread commercial application.
A suspension may be defined as any liquid in which
insoluble solids are dispersed and kept in a state of
fluid energy. The stability of suspensions used in coal
preparation range from nearly stable suspensions using
123
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ultra-fine magnetite to highly unstable suspensions of
relatively coarse sand in the Chance process.
The specific gravities of separation for coals range
generally from about 1.35 to 1.90. To achieve this range
of specific gravity while keeping the volumetric concentra-
tion at a reasonable level, it is necessary to either
select high specific gravity solids or to introduce upward
currents in the separating vessel. As the usually accepted
volumetric concentration is between 25 and 45 percent, a
size and specific gravity of the suspended solids must be
selected that will provide for the desired separating
specific gravity while at the same time have the required
medium stability. The coarser the solids, the higher the
settling rate, the lower the viscosity, and the easier it
is to recover the medium; the finer the solids, the lower
the settling rate (hence the greater stability), the
higher the viscosity, and the more difficult it is to
recover the medium. Additionally, the higher the specific
gravity of the suspended solids, the lower the volumetric
concentrations for a given specific gravity. It is,
therefore, possible to select the specific gravity, size
consist and volumetric concentration of the suspended
solids to achieve medium characteristics that provide
overall optimum performance and economy.
Control of density, viscosity and settling rate of a
suspension is necessary for efficient separation of coal
and impurities. A number of excellent discussions of these
properties of a suspension are available (see references).
7.3.1.1 Magnetite Dense Media Coal Cleaning In
general commercial usage, magnetite dense media coal
cleaning is a separation of coal from the ash, pyrite and
other impurities in a suspension of finely divided
124
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magnetite in water in which the coal floats and the
impurities sink. The stability of the suspension of
magnetite in the water is maintained by the fine magnetite
grind, the amount of coal and shale slimes and the general
agitation of the refuse-removal mechanism causing recircu-
lation of the magnetite media.
There is no standard flowsheet for dense medium
cleaning with a magnetite medium. Each plant is tailored
to produce a specified product from a raw coal having
specific washability characteristics. Functionally, the
process involves the following operations:
raw coal pretreatment,
cleaning,
product recovery and
medium recovery.
Raw coal pretreatment—Inasmuch as dense medium
processes cannot process the full size range of
the raw coal, it is necessary to limit the
particle sizes of the raw coal fed to the washer.
Limiting the top size of the coal sent to the
washer is usually accomplished by crushing,
screening or a combination of both and has been
discussed in Chapter 6. The most important raw
coal pretreatment function is the removal of
those sizes too fine for washing by dense medium
processes. If the finer sizes are to be
marketed without further cleaning or if to be
cleaned by dry methods, multideck vibrating
screens using heated screen surfaces are used
extensively. Where the fine sizes are to be
cleaned wet, screening usually is accomplished on
wet multideck vibrating screens or sieve bend
screens. It is imperative that this function is
done at high screen efficiency to prevent a
buildup of fines in the medium circuit which
increases the viscosity of the medium and signi-
ficantly increases the loss of media.
In addition to. presizing, the raw coal must be
wetted before washing. This is accomplished
125
-------
automatically if wet sizing is used or can be
accomplished by spraying the coal with water or
dilute media, or by wetting in a sluice contain-
ing medium prior to its entering the washer.
The surface moisture content of the raw coal
entering the washer is usually between five and
10 percent depending on its size consist. One
of the reasons for wetting the coal is to prevent
"rafting" of particles in the separator; another
reason is the need to feed to the separator a
known and constant amount of water which can be
compensated for by adding high specific gravity
of the dense medium constant.
Washing—The function of the washer is to effect
a separation of the raw feed into a clean coal
product and a refuse; some washers are designed
to produce a middling product in addition to a
clean coal product.
Washers vary widely in design, performance,
capacity and operation to the extent that there
is a washer of the type and capacity available
for any need. Because of the wide variety of
washers, they will be covered later in the
chapter.
Product recovery—The products from the washer
must be separated from the medium and the medium
subsequently recovered. In most cases, the
products flow over a short stationary screen
where the bulk of the medium is removed without
dilution and returned to the medium circulating
system. The products then flow onto a vibrating
draining screen for additional medium recovery
and then onto a vibrating rinsing screen where
sprays of water wash the remaining magnetite
from the products. The screens are made suffi-
ciently long to allow most of the water to drain
from the products (see Chapter 8). The dilute
medium from this operation is sent to the medium
conditioning recovery system.
Medium recovery system—It is the function of the
medium recovery system to recover the magnetite
that is rinsed from the products on the rinse
screen and to remove the nonmagnetic material
from a portion of the main medium circulation
system for viscosity control. The amount of
medium to be diverted from the main dense medium
126
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Magnetic
separators .
Raw cool
feed
D
Prewet
screens
Oversize
Recirculated water
Clarified water
Dilute medium
Dense medium
Undersize
to fine cool
circuit
Float .
| "^ TO fine coal
A circuit or waste
~i I° }
. . .9. -9- Clean cool
Pump
Pump
Simplified, Typical Denso-Medium
Coarse Coal Washer Flowsheet
Source: U.S. Buroau of Mines
RI #71^4
J.J.DAVIS
ASSOC I ATE S
Figure 7-5 I
DCN
-------
circulating system rarely exceeds 10 percent.
The actual amount that needs to be cleaned is a
function of the amount of nonmagnetic fines that
concentrate in the dense medium, due to either
inefficient prescreening or the friability of the
coal being washed.
The basic apparatus of a magnetite dense-medium coal
washing process is illustrated in Figure 7-5. The system
comsists of the following:
1. The separating vessel which is filled with the
suspension of magnetite and water. Figure 7-6.
Figure 7-6
Dense Media Separating Vessel
2. An overflow weir or some means of mechanically
assisting the coal across the surface of the
bath and out the separator. Figure 7-7.
3. When a third product is desired, a middling
removal system. Figure 7-8.
4. A refuse removal system. Figure 7-9.
128
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Figure 7-7
Mechanical Coal Removing System
Figure 7-8
Middling Product Removal System
129
-------
Figure 7-9
Refuse Removal System
5. Drain and rinse screens for removing magnetite
media from clean coal, middlings and refuse
products. Figure 7-10.
Figure 7-10
Drain and Rinse Screens
130
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6. A dense media sump and pump which collects and
drains media from all products and relurns the
media to the separating vessel. Fiqu 7-11.
Figure 7-11
Dense and Dilute Media Sump and Pump
7. A dilute dense media sump and pump which collects
the rinsings from the rinse screens of all
products and sends a message to media recovery
apparatus (see Figure 7-11).
8. A media recovery system is a cleaning system
which densifies and cleans the magnetite from
the associated coal and clay slimes. Figures
7-12 and 7-13.
9. A fresh water supply for rinsing sprays.
Figure 7-14.
10. A magnetite feeding system which adds fresh
magnetite. Figure 7-15.
11. A density control system which maintains a
desired specific gravity in the bath. Figure
7-15.
131
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Figure 7-12
Magnetite Recovery Unit
•
-------
Figure 7-14
Make Up Water Head Tank
5S8F
Ol fi nil
Figure 7-15
Magnetite Feed and Density Control System
133
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The basic operational sequence begins as the sized
feed for the vessel is pre-wet in a stream of circulating
water and is introduced at or below the bath surface.
The coal floats just below the bath surface and flows, or
is mechanically assisted out of the separator with some of
the magnetite medium. The high-ash material, shale and
other impurities sink in the magnetite suspension and are
removed from the bottom of the bath. The coal is drained,
rinsed of media and sized. The refuse is drained and
rinsed.
The drain portion from both products goes to the
dense media sump for direct return to the separator to
maintain the minimum level and stability in the bath. The
diluted media from the rinsing portion of the product
screens is piped to the dilute medium sump where the mag-
netite is thickened. The thickened magnetite is pumped to
a double stage of magnetic separators for further magnetite
concentration and medium cleansing. Overflow water from
the diluted medium sump is returned to the surface as
pre-wet and spray water. Figure 7-16 highlights a typical
magnetite recovery circuit.
The concentrate (thickened) clean magnetite from the
magnetic separator is returned to the separator bath via
the dense medium sump. A portion of water and slimes
removed from the coal and refuse by the magnetite separator
may either be used in the pre-wet screen on the incoming
feed, or may be sent directly to water clarifier-thickeners
where the solids go to a fine coal recovery circuit and
clarified water returns to the spray system.
The capacity of the separators (dense media washers)
is a function of the size constancy of the feed, the
quantity of near-separating gravity material in the feed
and the amount of refuse in the feed. The width of the
134
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Magnetite Recovery Circuit
The patented O.S.M. recovery circuit, used exclu-
sively in this country by Roberts & Schaefcr. is
unique in its ability to keep magnetite losses to a
minimum.
Each of the three main units of the recovery cir-
cuit has a specific function and. when combined
in proper sequence, they produce the most efficient
circuit for the recovery of magnetite.
The cyclone classifier receives the raw dilute
medium and concentrates the large part of the
non-magnetics In the underflow while directing
the major portion of the finely ground magnetite.
whether magnetic or not. to the overflow and
thence into the magnetite thickener.
The magnetic separator receives the underflow
from the cyclone classifier. Magnetics arc recov-
ered and directed to the thickener. Tailings are
diverted (o the fine coal cleaning circuit.
The magnetite thickener receives the cyclone
classifier overflow containing magnetite and mi-
nus 150M (nominally) coal solids, and also the
concentrated magnetite from the separator.
The thickener takes advantage of the self-floc-
culating properties of the magnetite lo anulonu-r
ate it magnetically and is sized to classify at the
same point as the cyclone thickener so as to purge
the system of coal solids.
The overall effect of (he circuit is to purify the
medium at each pass while retaining ihr major
portion of the non-magnetics, and to keep a ready
supply of magnetite in solution in the magnetite
thickener for use in rapid changes of pulp density.
CLASSIFIED IMGMf TIC
AMD NOW MAQHFUC
ueoiuu
CHLUTE MEDIUM
MAKE-UP MEDIUM
TO CLEANING VESSEL
J.J.DAVIS
ASSOCIATES
^Ar^Alil MLMY I Mf.lfgt I «s
Magnetite
Recovery Circuit
Figure 7-16 I DCN
135
-------
bath controls the capacity which ranges from 10 to 15 tons
of coal per hour per foot of bath width in the 1" to IV
size ranges, and from 15 to 25 tons per hour in a 2" to 3"
size range.
The use of magnetite (5.0 specific gravity) permits
practical suspension density ranging up to 2.0 specific
gravity. The lower limits per semi-stable suspension is
about 1.30 specific gravity.
The performance data of various sized fractions of all
the plants studied by the U.S. Bureau of Mines support the
following conclusions:
The recovery efficiency is generally decreased
as the size-fraction values decrease, but with
little correlation to the amount of near-gravity
material present.
The separating specific gravity value increases
as the size fraction value decreases, a normal
characteristic of upward current vessels.
The sharpness of separation criterion seems to
substantiate the generally accepted theory that
sharpness of separation deteriorates when
washing finer material. This can be shown by
the increase of probable error, the imperfection
factor and the error area in the finest sizes.
In general, the actual recovery, ash error and
total misplaced material increase as the particle
size decreases. The increase in total misplaced
material is normally caused by an increase in
the float coal reporting to the refuse.
7.3.1.2 Sand Cone Dense Media Coal Cleaning Sand
cones are used to clean raw coarse coal with specific
gravities below the practical range of Baum jigs, or to
clean coals that are difficult to clean efficiently
because of the amount of near-separating gravity material.
present in the feed. . Although sand cones normally clean
+V coal, they are capable of washing +1/16" coal, but
such use greatly reduces cone capacity.
136
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Sand flotation, as applied to the washing of coal,
means a floating of coal in a fluid mixture of sand and
water in which bone, slate and other refuse will sink. A
mixture of sand and water is maintained in a fluid state by
mechanical agitation and upward currents of water having
low velocity.
The most popular coal cleaning process using a sand
suspension is the Chance Cone process, first patented in
1917. The first anthracite and bituminous coal Chance Cone
plants were installed in 1921 and 1925, respectively.
The feature of the Chance Cone process distinguishing
it from most other dense medium processes is that the sand
particles are of such a size that they settle readily in
water. The process, therefore, requires some method of
maintaining the sand in suspension. This may be accom-
plished by stirring the sand-water mixture and using rising
currents of water of such velocity as to hold the sand in
suspension; the relative importance of each varies
according to whether the specific gravity of the medium is
high or low. In anthracite practice, where the specific
gravity of separation is commonly 1.70 or higher, stirring
is the primary method of keeping the sand and water
uniformly distributed throughout the cone. In bituminous
practice, where separations at 1.50 specific gravity are
common, the rising currents are the primary method.
The Chance sand cone apparatus consists of the
following:
1. a separator cone filled with a fluid mixture of
sand and water,
2. an overflow weir to permit the coal to float
out of the top of the separator,
3. a middlings column when a third product is
desired,
137
-------
4. a classifier column connecting with the base of
the cone,
5. an upward refuse value,
6. a refuse chamber,
7. a lower refuse valve,
8. desanding screens for removing sand and water
from the cone products,
9. a main sand sump to which all sand and water
from the clean coal desanding screen is conveyed,
10. a refuse sand sump to which all sand and water
from the refuse desanding screen is conveyed,
11. a circulating water pump to return water to the
cone agitator nozzles and desanding sprays,
12. a refuse sand pump to return sand and water to
the cone and
13. a manifold through which water for agitation is
supplied to the cone.
Figure 7-17 depicts the Chance Cone process.
The basic operational sequence of the Sand Cone
process begins with the feed to the cone being introduced
at the vessel surface. The coal floats just below the
surface of the fluid mass and flows out of the separator
with some sand and water. The bone, slate and other
refuse sink in the fluid mass and are removed by alternate
opening and closing of the two refuse valves.
The coal is dewatered, desanded and sized simulta-
neously and the refuse material is dewatered and desanded.
Sand and water removed by the desanding screens go to the
sand sumps where the sand settles out. Sand from the
refuse sump is pumped to the main sump and the sand from
the main sump is recirculated to the cone. Overflow water
from the main sand sump is returned to the cone and
138
-------
-Refuse chamber
filling tank
Agitator drive
JTT-
W
Cleaned coal desanding
and sizing screen
Refuse desanding
screen
Refuse sand
sump
Circulating water pump
Refuse sand pump
i A- Refuse {
IB- Sand I
! C- Agitator water i
i D- Feed j
j E- Cool !
I F- Overflow ,
Source: U.S. Bureau of Mines
RI S6606
J.J.DAVIS
ASSOCIATES
v'AfvAttE.s'fc.*^' fc*.;. % t c ^ *i
The Dense Media
Chance "Sand Cone"
Figure 7-17
DCN
-------
desanding sprays by the circulating pump. Fine silt that
settles out in the outer ring of the main sand sump is
drained from the settling tank to a thickener for recovery
of the water and the silt.
Owing to the upward water currents of low velocity in
the sand cones, the large particles are floated at slightly
lower specific gravities than the small particles. This
characteristic of the cone may be either advantageous or
disadvantageous depending upon the washability of the coal
and the market.
Refuse removal is usually effected in a double-gated
refuse chamber, which fills and empties from 20 to 60 times
per hour depending on the quantity of refuse in the feed.
However, one company successfully operates a cone that
continually siphons the refuse product onto a desanding
screen, thus eliminating the refuse chamber.
The feed particles to the separator may range from 8"
to 1/8" in size, however, treating such a wide range would
greatly impair the performance of the cone. When the size
range to be cleaned is wide, it is preferable to size the
feed and to use two separate washers. General practice in
the United States is to feed 4" or 6" top size material
with the bottom size of 3/8" or 1/4" to the separator.
The benefits of washing coal finer than 1/4" in a sand
cone probably are offset by the reduced capacity in
increased sand losses. However, in certain instances coal
is being washed down to 1/1.6" size successfully.
The capacity of the separator depends upon the size
consist of the feed, the quantity of near-separating
gravity material in the feed and the quantity of refuse in
the feed. In general, this capacity is approximately two
tons clean coal per hour per square foot of surface area.
140
-------
Separator capacity may decrease if the feed is too closely
sized or if the feed contains a large percentage of finer
sized particles, excessive near-separating gravity material,
or a large percentage of refuse. The nominal capacities of
10, 12 and 15 foot cones would be 155, 225 and 350 tons of
clean coal per hour when washing 6" x 1/4" bituminous coal
at 1.40 specific gravity.
The upper limit of practical separation specific
gravity is approximately 1.65 using silica sand; the lower
limit is about 1.35 specific gravity.
7.3.2 Dense Media Coarse Size Coal Washing Equipment
There are a number of commercially available dense
media coal washing devices. Only a few of the more
important units will be addressed to give the reader an
idea of the range of equipment and techniques available.
The Tromp process, developed by K. Tromp in Holland,
was the first to employ magnetite commercially as a medium.
The distinctive feature of the Tromp vessel is a bath of
dense medium which increases gradually in density from the
surface downward. All other established processes aim at
keeping the density as uniform as possible in order to make
a sharp separation between the material which floats and
the material which sinks. A common criticism of unstable
media is that it is difficult to maintain the required
uniform density. However, if the variation in density is
controlled to a predetermined gradation as in the Tromp
system, the advantage is gained that, in addition to the
coal floating to the surface of the bath, the middlings and
reject concentrate in the medium at different levels
corresponding to their densities and, thus, the equivalent
of series of float-and-sink separations takes place in one
bath. This is achieved in the two-product bath by admitting
141
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controlled gravity recirculating medium of the same density
through four feed points (headers) across the width of the
bath. Directional baffles direct the medium to four zones
vertically and horizontally. The gradation in medium
settling is controlled by sending a medium to the bath
which will give the correct specific gravity separation at
the cut point where the clean coal scrapers leave the bath.
The same purpose is achieved in the three-product bath for
control of clean coal middlings separation. However, to
control the refuse-middlings separation, medium of a pre-
determined higher gravity is admitted to the bath through
a single point with'its flow directed to the middle of the
bath. The same gradation principle applies.
Three different Tromp vessels are marketed in the
United States by the McNally Pittsburg Manufacturing
Company and serve as the standards for shallow bath
separators, two product separators and three-product
separators.
McNally Tromp Dense Media Vessel—The washing
unit shown in Figure 7-18 consists of a shallow
tank filled with a suspension of relatively
coarse material. The medium is introduced by
four horizontal pipes and distributed in horizon-
tal layers across the feed end of the bath by
baffle plates. It then travels the full length
of the bath, the top layer flowing through the
emission screen at the clean coal exit from the
medium level and finally discharging with the
refuse over the horizontal weir at the opposite
end of the bath. The material to be separated
is likewise distributed horizontally across the
full width of the bath in a uniform layer. This
is usually accomplished by means of a vibrating
screen which serves as a double purpose of
providing uniform distribution across the width
of the bath and removing undersized material
from the feed. The McNally Tromp bath makes a
sharp separation by the use of the McNally Tromp
principle of laminar flow combined with automatic
density regulation. The laminar principle
142
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Figure 7-18
McNally Tromp Dense Media Vessel
provides for continuous, uninterrupted horizontal
flow currents from the feed end to the discharge
end of the bath. This action compensates for any
tendencies of unstable media to settle out across
the entire width of the vessel. By adjusting the
fluid level the float material can be controlled
to keep moving the full distance of the bath in
a suspension layer of specific density. The
automatic density control circuit consists of a
density measuring device and a density recording
controller to maintain the recirculating media
at a constant, preset, specific gravity. A
differential pressure cell is mounted on the side
of the heavy media, recirculating sump to auto-
matically control the level in the sump.
The bath is available in widths from 4 ft. to 10
ft. with capacities up to 475 tons per hour of
raw feed depending upon the size range and the
amount of sink material in the feed.
McNally Tromp Three-Product Dense Media Vessel--
This vessel is designed to separate and clean
three products from a raw coal feed. Therefore,
a high and low gravity separation is obtained
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in a single unit rather than two.
shows this unit.
Figure 7-19
Figure 7-19
McNally Tromp Three-Product Vessel
Source: McNally-Pittsburg Manufacturing Company
McNally Tromp three-product vessel consists of a
shallow tank filled with high and low gravity
media consisting of a suspension of finely
ground magnetite and water. A low gravity medium
is introduced through the four horizontal feeders
and is distributed in horizontal layers across
the feed end of the bath by baffle plates. A
high gravity medium is introduced into the lower
portion of the vessel by a fifth header and
flows in a horizontal layer escaping through the
adjustable underflow gate.
The material to be separated is distributed
horizontally across the full width of the vessel
in a uniform layer. On entering the low gravity
medium the coal floats and is removed by a
scraper conveyor while the middlings and refuse
144
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sink to the high gravity section where the final
separation of the middlings and refuse is made.
The final separation is accomplished by a single
scraper conveyor which carries the middlings
float material on the top flight and the refuse
sink material on the bottom flight.
The laminar principle functions as discussed.
An air lift in the high gravity section accom-
plishes the same function for the high gravity
media. There is a minimum of turbulence in the
baths since the coal, media and conveyors move
en masse in a substantially horizontal direction
except for the refuse faction which settles
vertically. The media density and level circuit
is completely automatic.
McNally Lo-Flo Dense Media Vessel—The Lo-Flo
vessel shown in Figure 7-20 is essentially a
tank filled with heavy media to which coarse
coal is fed uniformly and gently. The operation
of the vessel more closely simulates the actual
laboratory sink-float conditions than any other
production vessel in its capacity and operation.
A single conveyor skims off the float product
and on its return removes the sink product. The
two products exit at opposite ends of the vessel.
The density is controlled automatically either
by bubble tubes, differential pressure (DP)
cells, or nucleonic devices. Operating level in
the vessel is maintained by constant overflow of
the media.
The Lo-Flo density media vessel is available in
widths from 6 ft. to 9 ft. The capacity will
vary with the size range and the amount of sink
material in the raw coal feeds, changes or
adjustments to the vessel which are required for
varying feed characteristics may be quickly and
easily accomplished.
Other types of dense media cleaning units are discussed
in the paragraphs which follow.
The DMS Dense Medium Precision Coal Washer,
shown in Figure 7-21, is manufactured by the
Daniels Company. It is a trough type unit using
a transverse flow where the introduction of raw
145
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Figure 7-20
McNally Lo-Flo Vessel
Source: McNally-Pittsburg Manufacturing Company
Figure 7-21
DMS Dense Media Coal Washer
Source: The Daniels Company
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feed and the discharge of clean coal are trans-
verse to the removal of refuse.
As the presized and prewetted feed enters the
washer, it is forced under the surface of the
bath by a patented submergence baffle. Thus,
the actual separation between float-and-sink
particles takes place well below the.surface of
the medium. Particles lighter than the specific
gravity of the medium rise to the surface and
overflow the weir along with a quantity of dense
media; particles heavier than the specific
gravity sink to the bottom of the bath where
they are removed continuously by a slow-moving
rectangluar flight conveyor.
Approximately 10 percent of the circulating dense
medium enters the washer through a series of
purge ports. This gentle upward current flows
through the bedded refuse moving between the
conveyor flights along the bottom of the vessel,
purging the refuse of coal which might have
become trapped.
The DMS Washer is available is capacities ranging
from 100 tph to what is claimed to be the world's
largest dense medium washbox, featuring a feed
capacity of 800 tph, a refuse removal capacity of
250 tph and a clean coal overflow weir 20 ft.
long.
The Link-Belt tank-type heavy media separator
(see Figure 7-22) is manufactured by the Link-
Belt Company. Prewetted and sized feed enters
the vessel together with dense medium of the
desired specific gravity. The clean coal floats
across the bath and discharges over a weir with
the overflowing medium; the rejects sink to the
bottom of the tank and are removed by means of a
double strand chain-and-flight conveyor.
A greater part of the medium drained from the
clean coal and reject is collected in a medium
sump and is pumped back to the feed inlet sluice;
the remaining medium is fed back to the funnel
shaped bottom of the tank where it is used to
create an upward current in the vessel to prevent
the magnetite from settling.
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REFUSE
DISCHARGE
FLIGHT
FLOATS
DISCHARGE
PADDLE
(OPTIONAL)
Figure 7-22
Link-Belt Tank-Type Heavy Media Coal Washer
The Barvoys vessel, shown in Figure 7-23, is a
deep trough-type vessel. The Barvoys System was
designed originally in Germany for washing soft-
structure coals and employed suspensions of
barytes and clay which approached a true liquid.
As now fabricated and marketed by the Roberts
and Schaefer Company, it is designed to use a
standard magnetite dense medium. The Barvoy
trough-type washer utilizes lifters to remove
the clean coal product out of the bath, thus
reducing the quantity of medium to be recircula-
ted through the unit. The refuse sinks to the
bottom where it leaves the washer via a chain-
and flight conveyor. Because of its down draft
principle of operation, there is a minimum of
degradation and no middling build-up or gravity
fluctuation within this vessel. Capacities up
to 500 tph per vessel are available.
The DSM trough-type vessel, developed by the
Dutch State Mines, is shown in Figure 7-24. It
now is manufactured and distributed in the United
States by the Roberts and Schaefer Company. The
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Source: Roberts & Schaefer Company
J.J.DAVIS
ASSOCIATES
Barvoy Heavy
Media Vessel
Figure 7-23 DCN
-------
Source: Roberts S Schaefer Company
J.J.DAVIS
ASSOC I ATES
DSM Shallow
Bath Vessel
Figure 7-24 DCN
-------
uses a chain-and-flight conveyor for
removal of the float-and-sink products. Vessels
having a capacity up to 360 tph are available.
lleyl and Patterson H&P Heavy Media Washbox for
cleaning coarse coal is shown in Figure 7-25.
Presized raw coal enters one side of the washer
along with a small portion of dense medium. The
float coal flows across the bath and overflows
the clean coal weir with the bulk of the dense
medium. Sink settles to the bottom of the
vessel by means of a chain-and-flight conveyor.
Figure 7-25
H&P Heavy Media Wash Box
Source: Heyl and Patterson, Incorporated
The major portion of the circulating dense medium
enters the vessel via a baffle over the entire
length of the feed side of the vessel where it
discharges near the bottom of the bath. This
flow of medium provides a gentle current which
assists the float coal toward the clean coal
overflow weir. A small portion of the dense
medium is introduced at the bottom of the vessel
to add stability to the suspension and to purge
the sink of trapped float particles.
Dense media washers not specifically addressed include the
miscellaneous manufacturers of the Sand Cone process and
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those that produce the different drum-type vessels, such as
the WEMCO drum separator.
7.3.3 Hydraulic Separation of Coarse Coal
In general commercial usage, the hydraulic separation
of coarse coal is restricted to jigging.
Jigging is a process of particle stratification in
which the particle rearrangement is based upon the differ-
ences in their relative specific gravities and results from
an alternate expansion and compaction of a bed of particles
by a pulsating fluid flow. The particle rearrangement
results in layers of particles which are arranged by
increasing density from top to bottom of the bed. This
response, developed from the many and continuously varying
forces acting upon the particles, is a solid-fluid
separation more related to particle density and less to
particle size.
Jigging is one of the oldest techniques for washing
coal. Jigs have been designed in many forms and they are
still the most common type of coal cleaning device.
Although some jigs have used only air as the separating
medium, practically all jigs today use water as the medium.
The water is actuated by means of pistons or air under
pressure producing the pulsations required for the strati-
fication of the lighter specific gravity coal particles
from the heavier rock or impurities in the raw coal. One
complete upward and downward movement of the water is
called a cycle or revolution. A half cycle is called a
stroke. The relative upward movement of the water through
the screen is called the pulsion stroke; the relative
downward movement of the water through the screen is called
the suction stroke.
152
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The stratification is usually carried out in a rec-
tangular, open-top container, called a jig, in which the
mass of particles (termed a "bed") is supported on a
perforated base through which the water flows in alternating
directions. Following the particle stratification, the
particle bed is physically "cut" at any desired particle
density plane thus creating the desired quality products.
Figure 7-26 graphically simulates the results of the
stratification process and highlights the susceptibility
Figure 7-26
Simulated Results of Stratification Process in
a Coal Washing Jig
of the particle bed to physical cutting at desired particle
density planes.
The mechanics of the jig includes the means for
continuously introducing the raw coal for moving the water
through the coal bed in a controlled manner as well as for
153
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separating and removing the stratified particles from the
system in two or more product groups.
In coal preparation, this highly versatile unit opera-
tion is more preferably applied to a wide size-range of
particles with top sizes up to eight inches than to a
closely-sized fraction. Single jig washers have capacities
from five to greater than 700 tons per hour of feed coal.
The separation results attainable by jigging have favored
this unit operation as optimum for creating a clean coal
product as required by steam coal specifications. Although
the jig is used in preparing coals which are difficult to
separate, its limitations to achieve both quality products
and high recovery are being recognized in comparison with
heavy media-based processes which make sharper separations
from feeds having high "near-gravity" contents. The
accuracy of the densimetric stratification in the upper
portions of the jig bed are less precise and, as in most
mineral preparation unit operations, high recovery and
product quality are interdependent and inverse process.
characteristics.
Jigs are made in three different types differing
mainly in the mechanism for getting the reciprocating
movement of the water relative to the screen:
Plunger Type—in which the movement is caused by
the reciprocating of a plunger moving in a
compartment of the tank.
Basket Type—in which the box containing the bed
is reciprocated in still water.
Air Pulsated Type—in which the tank is built in
a shape of a U tube and the movement of the water
is caused by applying low pressure compressed air
to the closed leg of this U tube and then exhaust-
ing it. , .
154
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The greater number (about 75%) of jigs in use are air
pulsated and are called Baum jigs, named after the original
inventor, Herr Fritz Baum of Germany, who developed it over
75 years ago. In America the Baum jig is built as a multi-
cell series arrangement and since it takes a mixed sized
feed and requires a source of compressed air in addition to
the customary jig accessories, it does not lend itself to
the construction of small units. Consequently, Baum jigs
are the largest of this class of equipment.
The jig box is a U-shaped steel container divided into
several sections as indicated in Figure 7-27. On one side,
longitudinally near the top, is a perforated screen plate
which supports the particle bed and on which the particle
separation is effected. The region below the support screen
and forming the bottom of the U is referred to as the "hutch
compartment". Usually a screw conveyor is located at the
Figure 7-27
Typical Baum-Type Jig
155
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bottom to remove fine particles which .have.passed through
the screen with the flowing water. . ' ;.... .
On the side opposite the screen plate is a chamber
(sometimes referred to as the pulsion chamber) in which the
water pulsations are initiated. In the Baum jig, a sealed
air chamber above the hutch water compartment is fitted
with an air valve which connects to a high pressure air
supply. This valve is actuated mechanically to admit air
•over the hutch compartment forcing water through the
supporting screen base to expand the bed. In another valve
position, the air above the water in the hutch compartment
is allowed to exhaust under the pressure head developed by
the water and particles. In the plunger or "bash" type
unit, a piston-like plunger operating from an eccentric,
forces the water through the perforated screen plate. The
upward movement of the water through the screen from air
pressure or plunger-activated water pressure is referred to
as the "pulsion" stroke while the downward water movement
is termed the "suction" stroke.
To better 'understand the operation, consider first a
single cell. This cell is filled with water until the sur-
face rises almost to the air slide valve connection. The
raw coal to be separated is put on the jig screen,
compressed air is supplied to the slide valve, and the
eccentric shaft started turning over. During half the
stroke of the slide valve compressed air is admitted into
the closed end of the one leg of the cell. This air exerts
its pressure on the surface of the water and forces it down
through this leg, around the turn in the hutch, up the other
leg, through the jig screen and then through the bed of raw
coal. This is the pulsion stroke. At the end of this half
of the valve stroke the compressed air is cut off and
156
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remains cut off during the second half stroke. In the
second half stroke the valve opens a passage for the
release of the compressed air in the closed leg of the
cell and exhausts it to atmosphere. The surface of the
water in the open leg, having been raised above that in
the closed leg by the force of the air, now falls back
downward and tends to equalize with the surface in the
closed leg. This is the suction stroke. This double
stroke of the valve, with the resulting pulsations of the
water, is repeated with each revolution of the shaft.
At this point, without going into the theory of
jigging, it must be accepted that the falling velocity of
coal is less than that of the heavier refuse and, there-
fore, during the pulsion stroke, the coal will rise
farther in the bed than an equivalent particle of refuse.
During the suction stroke the refuse will fall farther than
an equivalent particle of coal. After a sufficient number
of pulsations the purest coal will be concentrated at the
top of the bed while the refuse will be at the bottom on
the jig screen. There will not be any sharp interface
above which there will be coal and below which there will
be refuse. There will be a gradual gradation from the
lightest, purest coal in the top stratum to the heaviest
refuse at the bottom. Figure 7-28 displays the various
stages in the stratification process.
Any quality of clean coal can be removed by scraping
off layer after layer starting from the top. The quality
of the aggregate will become lower and lower as more layers
are added.
The U-shaped container as a whole acts as a passage-
way through which the pulsations from the sealed chamber
are delivered to the materials resting on the screen. The
157
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o
0 .
O e
O ®
o®
fHH
x^/
SETTLING
CLASSIFICATION
ALONE
0
O
6 •
o •
o •
w
ffi\
W
|H|
VW
SETTLING
CLASSIFICATION
PLUS
DIFFERENTIAL
o ^
o f
0 0
o
REVERSE
ACCELERATION
O COAL BY DENSITY
^ REFUSE BY DENSITY
r^o000'
CJ
(j/i/\9>
^mff
COMBINATION OF
ALL THREE
WATER FLOW »-
INITIAL
ACCELERATION
STILL BATH SUCTION PULSION
STROKE STROKE
Figure 7-28
Various Stages in the Stratification Process
jig box is divided vertically into compartments. The
compartments are separated by fixed weirs which control the
flow of the float strata. A compartment is actually a
complete jig in itself including means of separating and
removing the lower particle layers from the screen bed.
Thus, a multi-compartment jig is really a series' of two or
more jigs designed to produce multiple products and
function as a primary separator (remove heavier refuse) and
a secondary operation (produce a quality coal product),
i.e., the float material from one compartment feeds into
the second compartment.
In turn, each compartment is divided into two, three
or four cells. The number of cells is varied according to
the difficulty of separation, each representing a "stage"
of washing. Each cell can be controlled separately as
158
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regards to the pulsations and water introduction. Water is
introduced continuously into each cell to replace that
removed with the products and to fulfill other functions.
The water introduction plays a major role in the jig
operation and its volume is an important control parameter.
The support screen normally has 1/4" aperatures,
although openings as large as 1 1/4" have been reported.
The size of the openings is used as a means of modifying
suction intensity or to offer some control of the fine
particle sizes when the feed is high in flaky impurities.
Within the solids discharge location at one end of
each compartment, the two layers (clean coal and refuse)
are split and a refuse ejector withdraws the bottom layer
(refuse or middling) as it is collected on the screen
plate and drops it into the boot of an elevator adjacent
to the hutch compartment. The elevator with its boot is
built integral with the jig. The adjustment of the refuse
gate height, the refuse withdrawal rate and a float control
determines the refuse separation. The rate of refuse
withdrawal is usually controlled by a float located in the
jig bed. The upper layers containing quality coal pass
over a weir into a delivery sluice for dewatering.
A control (float or other device) is immersed in the
jig bed at a point near the level where the division of
the coal strata from refuse strata occurs. It represents
an automatic control sensor. The float functions as a
hydrometer that measures the specific gravity of the coal-
refuse-water mixture at a selected level in the jig bed.
The measurement is usually made at the peak of the pulsion
stroke. The specific gravity measured is a function of
the refuse level in the jig bed. The float height level
varies with specific gravity of the bed at the set location
159
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and actuates suitable mechanical devices to change the rate
of refuse withdrawal. The floats are subject to a high
wear rate.
Although there is much similarity in plunger and Baum-
jig cycles, there is a significant difference which dis-
tinguishes them. Those aspects of a Baum jig which control
air volume or pressure may be related to the nature of the
strokes in a plunger-type jig. In the pulsion stroke of a
plunger jig, it is doubtful if the mechanical attainment
of the initial rapid impulse desired to lift the bed is
fully adequate or is followed by a sufficient speed
reduction to allow optimum bed opening and direction
reversal of the flow. Too slow a plunger speed may retard
downward bed motions thus reducing efficiency of the
suction stroke. During the suction stroke in a Baum jig,
the water and particle mass is moved solely by gravity;
but control can be exerted by the rate of air release and
water introduction, whereas the configuration of the
eccentric or cam activating the plunger governs in the
mechanical type. It is the control capability of the
"back suction" which is unique in the Baum concept. As
regards densimetric stratification, back suction is always
objectionable as it modifies particle settling rates and
enhances the compact bed formation. Thus, the cycle control
tends to be more versatile and effective in an air-operated
jig, which results in a relatively low capacity per unit
screen area for the plunger jig and also a closer adjust-
ment to attain equivalent separations. The Baum jigging
action is obtained by delivery of a suitable volume of air
at the proper pressure to the air receiver. As air is
admitted on the pulsion stroke of a Baum jig, the air
pressure produces a sharp upward movement of the water,
since water compresses very little. When the incoming air
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is stopped, the air in the pulsion chamber continues to
expand, simultaneously reducing the air pressure. During
this reduction in air pressure, the water movement
decreases and the particle bed opens from the bottom upward.
The air-pulsation principle permits a closer approach to
unhindered stratification between pulses, thus a more
effective cleaning of all sizes. It is the nature and
frequency of the jig cycle which achieves the desired
particle stratification.
7.3.4 Hydraulic Coarse Coal Cleaning Equipment
Generally speaking, the fundamental features of jigs
were known from antiquity onward, but little progress was
made until recent times. The principal features of jig
design that require attention are:
Development of a proper jigging cycle, with
ready adjustments as to length of stroke, dura-
tion and character of cycle.
Even transmission of jigging motion from point of
application to point of utilization of motion.
Use of suitable bed material or ragging, when-
ever a hutch product is secured.
Rapid evacuation of strata and conveyance from
jig.
Design with respect to the relative tonnages of
heavy and light strata.
There are a number of hydraulic jigs commercially
available. Several of these units are addressed in detail.
McNally Norton Standard Washer—This washer as
depicted in Figure 7-29 is a fully automatic unit,
which stays in balance at a pre-determined
specific gravity separation point despite
variations in tonnage or characteristics of the
incoming feed. It is a Baum-type jig using air
to distend the bed intermittantly to effect
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stratification of both coal and refuse on the
limits of specific gravity.
Operation of the washer is simple and positive.
Raw coal is cleaned in two stages. A primary
separation at the feed end of the washer removes
the heavier refuse material. The secondary
compartment divides the coal into a bottom layer
of middlings on which rides a second layer of
quality coal. At the discharge end the two
layers are split, the good coal passing into a
primacy sluice. Middling materials are
discharged separately for rejection or
reprocessing; or they may be delivered as a
second grade of coal.
Figure 7-29
McNally Norton Standard Washer
Source: McNally-Pittsburg Manufacturing Company
A primary advantage of McNally Norton washer is
its ability to handle fluctuating tonnages, and
varying qualities of raw coal feed while deliver-
ing a continuously uniform product. Tonnages
that can be handled by one washer range up to
500 tons per hour.
McNally Mogul Washer—Illustrated in Figure 7-30,
this washer is designed primarily to provide an
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automatic Baum-type jig that can easily handle
flat slabby refuse. Forward flow of the coal and
reject increases capacity in the primary end of
the Mogul washer.
Any stratification made in the first two cells of
the secondary compartment is not distended or
interrupted, but is further stratified in the
remaining two cells, giving a cleaner more
efficient separation. The bed is maintained at
a selected depth by the float mechanism which
varies the opening of the discharge gates to
match the volume of reject in the washer feed.
The evacuating gates are air operated. The gates
consist of multiple pivot fingers. These
discharge gates are equipped with a perforated
stainless steel plate through which the upward
impulses pass from the adjacent washing cell.
The washer is available in capacities up to 600
tph for some coals.
Figure 7-30
McNally Mogul Washer
Source: McNally-Pittsburg Manufacturing Company
163
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Figure 7-31
McNally Mogul Washer as Observed in a Preparation Plant
McNally Giant Washer--The tonnage capacity has
been greatly increased by rearranging the
washing cells. The washer has a total of 180 sq.
ft. of effective washing area, providing 20%
greater washing area, and a tonnage capacity of
750tph. The combined washing compartments are
10 ft. wide. The primary compartment consists
of two cells while the secondary compartment
consists of four cells. Any stratification made
in the first two cells of the secondary compart-
ment is not distended or interrupted, but is
further stratified in the remaining two cells
giving a cleaner, more efficient separation.
This unit is shown in Figure 7-32.
Adjustable positioning of the pistons along the
push rod provides a wide range of adjustment in
the intake and the exhaust interval of each cell.
The various speed drive permits setting the
impulse frequency to suit the separator require-
ments while maintaining positive synchronism of
the impulse to each cell. The impulses to the
primary cells are directly and positively opposed
to those of the secondary cells. Spiral
conveyors for handling the gob material have been
eliminated.
164
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Figure 7-32
McNally Giant Washer
Source: McNally-Pittsburg Manufacturing Company
Batac Jig--To improve the performance and to
obtain greater capacities than available with
standard jigs, recent radical modifications have
been made in the design and operation of this new
jig called the Batac.
In the Batac jig the principle of causing the
pulsations to the raw coal feed in the water
165
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medium is the same as in the Baum jig. However,
the methods of air distribution, the pulsation
action of the air by new type of valves, and the
bed control have been greatly improved and
automated.
In the Baum jig, air under pressure is forced
into a large chamber on one side of the jig
vessel, with the air pulsated by the action of
sliding or rotary valves (see Figure 7-33). This
creates a pulsating and suction action in the jig
water, thereby causing a stratification of the
particles that are to be separated in accordance
with their relative specific gravities;
Distribution of this force beginning on one side
of the jig frequently causes unequal variations
in the jigging action over the width of the jig
bed and, therefore, unequal variations in the
stratification within the bed.
AIR INLET IX "it: t ^
AIR CHAMBER''
WATER PULSATION
SCREEN
Figure 7-33
Baum Jig Cross Section
Air is forced under pressure into an
air chamber on one side of the jig
vessel and is pulsated by action of
sliding or rotary valves.
166
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In the Batac jig, there is no side air chamber.
Rather, it is designed with a series of multiple
air chambers, usually two to a cell, extending
under the jig screen for its full width, thus
providing for a uniform air distribution.
This principle of air distribution originated
in Japan and is used in their Tacub jig. The
Batac, derived from the words Baum and Tacub,
was developed using this principle by Humboldt
Wedag of Germany.
Figures 7-34 and 7-35 illustrate a six-cell
three compartment Batac jig. The heavy specific
gravity material in the coal discharges through
the screen plate perforations and at the end of
AIR EXHAUST
AIR EXHAUST
FEED
PRODUCT
Figure 7-34
Side View Cross Section of Batac Jig
Jig is designed with a series of multiple
air chambers, usually two to a cell,
extending under the jig screen for its
full width so as to provide uniform air
distribution.
167
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the compartments through shale ejectors. Primary
rejects or refuse may be discharged by the bucket
elevator from either the first compartment alone
or, depending upon the quantity of heavy refuse
to be discarded, from both the first and second
compartments.
Secondary rejects may discharge to the second
bucket elevator, either from the second compart-
ment or only from the third compartment. The
secondary rejects may, if the character of the
material warrants, either go to final reject, be
returned back to the jig feed for recirculation,
or may be classed as middlings or secondary
product. The secondary rejects may also be
recleaned in a heavy-media system.
This latter step may be desirable in some very
difficult coals containing a high percentage of
near gravity material or if it is necessary to
clean the coal at a low specific gravity of
separation. This retreatment, if required,
involves only a relatively small tonnage of the
total jig feed.
The standard Baum jig uses either piston or
rotary type of air valves. The Batac jig uses
a flat disc design, which provides a sharp cutoff
of the air input and exhaust. These valves, both
for inlet and outlet of air, can be infinitely
varied as to speed and length of stroke. The
ability to vary the cycle characteristics of the
pulsation and suction is of immense value in
opening and closing of the bed to obtain proper
stratification in the bed as the raw coal
characteristics change in terms of size consist
and/or variable densities.
These air valves are operated from an electronic
solid-state instrument cabinet generally
installed in the plant control center.
The electronic components for controlling the
action of the air valves in the Batac jig (whose
speed is measured in milliseconds) are in
modular slide-in form and, if a malfunction does
occur, they can easily be replaced in a few
moments.
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WATER PULSATION
AIR INLET
'AIR CHAMBER
SECTION A-B
Figure 7-35
Batac Jig Cross Section
Heavy specific gravity material in the
coal discharges through the screen
. plate perforations and at the end of
the compartments through shale ejectors.
For controlling the bed level of the stratified
material in the jig, a number of floats are
installed along the width of the jig in each
compartment. These floats are automatically
controlled by inductive coils which can be set
to measure the various densities of separation.
They trigger hydraulically operated refuse
ejector valves which increase or decrease the
bed level, as required.
In case of a plant stoppage or loss of feed to
the jig, a float mechanism near the feed end of
the jig is used to bypass the jig air used for
pulsation. This prevents a disturbance of the
jig bed and avoids the usual misplaced material
which would otherwise occur if the jig is
operated without raw coal input.
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7.3.5 Separation of Intermediate Size Coal
The current emphasis on cleaning the smaller coal
particles is the result of new mining techniques and
equipment which produce a finer size of ROM coal, a result
of the need to crush coal to further reduce its size prior
to washing to liberate coal-associated impurities such as
pyrite (only through the liberation of these impurities
can an acceptable final product be provided at the maximum
yield), and a result of ever-increasing production costs
which require the maximum recovery of clean salable coal
to justify the existence of the industry. As pointed out
in previous discussions, the cleaning of the smaller coal
sizes is inherently more difficult and the preparation
costs increase with decreasing size.
The differentiation between intermediate and fine
size coal cleaning equipment becomes very complicated and
somewhat arbitrary. On an industry-wide basis, coal
cleaning equipment is classified as either coarse or fine
coal cleaning equipment. However, for the purpose of
clarification this disucssion will divide the "fine" coal
cleaning equipment into intermediate size coal cleaning
and fine size coal cleaning equipment. The intermediate
size coal cleaning equipment addresses primarily 3/4" x 0,
although some of the equipment discussed has top sizes in
the range of IV and other generally address V x 0 coal.
The fine size coal cleaning equipment discussion will be
restricted to the froth flotation of the ultra fine coal
sizes primarily 48-mesh x 0. A complete understanding of
the interdependence and inter-relationships of both inter-
mediate and fine size coal cleaning equipment may be
obtained from a review of the flow charts discussed in
Chapter 11.
170
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The intermediate size coal cleaning equipment may be
classified into four general groups. These are:
dense media cyclones,
hydrocyclones,
wet concentrating tables and
fine coal launder and jigs.
7.3.5.1 Dense Media Cyclones—Generally speaking,
crushing raw coal tends to free particles of good coal
from particles of impurities. However, with the reduction
of particle size below V, the difficulty of gravimetric
separation increases. This is so, because the time
required for any particle to settle in water is dependent
upon its specific gravity and the resistance of the water
to the settling of that particle. The larger the particle,
the faster the sinking rate in proportion to a given fluid
resistance-mass ratio.
Conventional jigs take advantage of this fact with
the impulses and free water to form strata of different
specific gravity material. As particles become smaller,
settling rates are increased. The settling time of fine
particles can be reduced by the application of force to
them. Figure 7-36 depicts a basic dense media cyclone and
the idealized flow pattern within the cyclone.
In a cyclone, this force is brought to bear centrifu-
gally by admitting raw coal and water under pressure into
the cyclone tangentially near the top. The resultant
forces are centrifugal. In a typical cyclone the centrifu-
gal force acting on a particle in the inlet region is
about 20 times greater than the gravitational force in a
static bath. As the feed descends in the conical section
of the cyclone, the centrifugal force is further increased
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and may reach to over 200 times gravity at the apex. At
this point, the cyclone has accomplished a size classifica-
tion of the particles resulting from the fact that under
centrifugal force, the larger particles will travel to the
perimeters of the cyclone and the smaller particles will
remain near the center.
WnhtdCool
/ Feed ml»!
Z Overflow chomber
3 Wo&hed coal outlet
4 Cylindrical section
5 Conical section
6 Replaceable underflow orifice
7 Vortex finder
Fwdl
Wotted Cod
Ritutt
Figure 7-36
A Dense Medium Cyclone and the Idealized Flow Pattern Within
To achieve a gravimetric classification, the water is
made dense by the addition of fine-ground magnetite with
the result that the particles having a higher specific
gravity are forced to the permiter of the cone and passed
out through the apex as refuse, while the particles of
lesser specific gravity remain near the vortex finder and
pass out through the top of the cone as clean coal. In
conventional cyclones, the mass generally is admitted at a
tangent. Gravimetric classification commences in the feed
line and arrives in the cyclone partially separated,
leaving for the cyclone itself only the final gravimetric
separation.
172
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The general flow pattern of the medium in a cyclone,
shown in Figure 7-36 consists of a descending vortex that
originates at the inlet and progresses through the cyclone
to the underflow outlet. As the descending vortex passes
down the cyclone, part of the fluid peels off toward the
center of the cyclone to form an ascending vortex. This
ascending vortex, in turn, surrounds a cylindrical air
core that encircles the entire longitudinal axis of the
cyclone. An additional factor that influences the separa-
tion is the progressive increase in specific gravity of
the medium as it descends toward the apex. This increase
occurs because the centrifugal force also tends to force
the medium particles toward the cyclone wall. Therefore,
they are preferentially caught in the descending vortex
resulting in progressively higher concentrations of medium
particles as the apex is approached. As might be expected,
then, the specific gravity of the medium flowing through
the underflow orifice is higher than the specific gravity
of the circulating medium. Conversely, the specific
gravity of the medium passing through the overflow orifice
is less.
If there is some mystery to cleaning coal by mixing
it in a dense fluid and whirling it around in a cone, it
is understandable. The paths followed by the coal and
impurity particles in a cyclone have been studied by
observation in a glass or clear plastic cyclones and are
still not fully understood. The refuse particles flow to
the wall soon after they enter the cyclone. They are
entrained in the descending vortex and are discharged
through the underflow orifice. The coal particles are also
initially entrained in the descending vortex. Some of
these migrate to the ascending vortex in the upper part of
the cyclone. Curiously, a large number of the coal
173
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particles descend well into the conical part of the
cyclone before they are trapped by the ascending vortex.
This behavior has been explained by postulating a barrier
of high specific gravity that is due to circulating medium
particles in the lower part of the cyclone. When the
descending coal particles reach this zone, they migrate
toward the central air core. They are then caught in the
ascending vortex and pass through the overflow opening.
The existence of a barrier, however, cannot entirely
explain the path of the coal particles because observation
of the coal particles in a glass cyclone using an organic
heavy liquid shows that they behave similarly; that is,
many coal particles descend well into the conical section
before they migrate to the ascending vortex. Clearly, a
heavy liquid is homogeneous and a barrier cannot be present,
yet the separation is very sharp. It is also interesting
to note that the specific gravity of separation is almost
always higher than the specific gravity of the medium when
using either a heavy liquid medium or a magnetite dense
medium.
The dense media cyclone is generally selected for low
specific gravity separations where there are high accumula-
tions of near gravity materials. Both fine and coarse coal
medium systems can be used advantageously and economically
when combined. The top size that any cyclone cleaner
should be fed depends upon the design of the entire coal
washing plant. If a washing plant uses either coarse dense
media or jig washing in combination with a cyclone, the
selection of the cyclone depends upon the point of separa-
tion most economical for the highest recovery of fine and
coarse coals. That point of separation may be anywhere
from V to iy• Generally, it is not economical or
advantageous to go to sizes above V in cyclone washeries
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if both coarse and fines are washed. If a cyclone washer
is to be the only washer installed in the plant, more than
likely the feed size would be approximately IV. This top
size, again, depends upon the individual washability
characteristics of the coal which indicates the proper top
size where a maximum yield will result when obtaining a
predetermined ash content.
A number of factors relate to the proper selection of
cyclones for any given problem. The size and number of
cyclones required for any given situation depends upon the
size of the coal to be treated in the cyclone, the wash
coal recovery expected and the suitability of a particular
bank of cyclones to a particular situation. Cyclones
could be offered in many different sizes to accomodate each
and every problem. However, most manufacturers have found
it practical to offer cyclones in two or three sizes, such
as 18, 20 and 24 inches. The size relates to the inside
diameter of the inlet chamber. Smaller sizes are available.
Larger sizes are being studied. Regardless of the size
most economical and selected for the particular problem,
preparation engineers are capable of designing the entire
circuit to suit each and every application. The normal
design capacity for 20 inch cyclones is approximately 50
tons per hour and for a 24 inch cyclone is approximately
75 tons per hour. The normal refuse design capacity is
about 60% of the cyclone feed capacity. Figure 7-37
depicts a typical dense media cyclone circuit. A media
recovery circuit is depicted in Figure 7-16.
The cyclone is useful for washing coal only when it
is properly integrated into a complete coal washing system
for fine coal. The effectiveness of any cyclone is
critically dependent upon the control of the dense medium
itself and is economically feasible only when the magnetite
175
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used in the dense media can be reused with a minimum of
losses. The largest loss of magnetite in any plant gener-
ally occurs from magnetite adhering to the refuse and to
the clean coal product. Some losses also occur with the
tailings from the magnetic separator. In preparation
plants where large tonnages are concerned, additional
equipment is included in the plant for recovery of very
fine coals (% mm x 0), i.e., flotation cells, filters and
thickeners. Since added equipment is used in these more
complex plants, it is possible to recover magnetite more
efficiently. For example, the tailings from the magnetite
separators may be fed to the froth flotation circuit where
any residual magnetite will report as refuse to the flota-
tion cells. If a magnetic separator is used on the
thickener underflow (flotation tailings) added magnetite
may be recovered. Additionally, in some heavily equipped
plants, the use of a centrifugal dryer on the clean coal
rinsed product may be added. By the addition of a spray
in the centrifuge, more magnetite is rinsed from the clean
coal which reports to the effluent from the centrifuge.
This, in turn, is directed to the flotation cells for
recovery.
7.3.5.2 Hydrocyclones—A hydrocyclone is very similar
in construction to a heavy media cyclone but is less
efficient without the magnetite. Essentially, it is a
cylindro-concial unit with an included apex angle of up to
120°, much greater than the included apex angle of the
dense media cyclone which is around 14°. The hydrocyclone
also has a longer vortex finder than does the dense media
cyclone or the hydraulic or classifying cyclone. Figure
7-38 depicts a cross section view of a typical hydrocyclone
and demonstrates the separation process. The coal and
water slurry is introduced tangentially and under pressure
176
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Source: Roberts s Schaefer Company
J.J.DAVIS
ASSOCIATES
Typical Dense Media
Cyclone Circuit
Figure 7-37 DCN
-------
into the central feed chamber. The cycloidal configuration
of the inlet imparts an initial circular motion to the
slurry and initial centrifugal separation of the particles
begins. As the slurry moves downward into the conical
section, the centrifugal force acting on the particles
increases with the descreasing radii.
Particles of different sizes and specific gravity form
a hindered settling bed in the first conical section (A)
(refer to Figure 7-38), and the separation process takes
place in three separate steps. Light, coarse particles
are prevented from penetrating the lower strata of this
bed by the coarse heavy fractions (middlings and refuse).
As a direct result, the water as it passes from the peri-
phery of the hydrocyclone towards the vortex finder erodes
the top of the stratified bed and removes the light coarse
particles via the central current around the air core and
up the vortex finder.
The remainder of the bed which has not measurably lost
its stratified character is forced into the second conical
section (B) by the mass of new material entering the
hydrocyclone. As indicated, the centrifugal force is
considerably increased and additional stratification and
erosion takes place. As the lighter pure coal particles
are removed, the heavier "middling" coal particles are
exposed. The lighter of these middling particles are swept
up and discharged via the vortex finder. The heavy
middlings that spiral upward in the central current of
departing water may by-pass the orifice of the lower vortex
finder due to their higher specific gravity. Consequently,
the coarse heavy middlings fraction tends to recirculate
to the stratified bed and finally enters the third concial
section (C).
178
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1)1 \(.lf U1M MIC \ !!•:« (II
sKi-AK vi ION sKiji I-:N('!•:
J.J.DAVIS
ASSOCIATES
HYDROCYCLONE
CROSS SECTION &
FLOW DIAGRAM
SOURCE: McNALLY-PITTSBURG
Figure 7 38 DCN
179
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In this last and smaller conical section, the bed is
finally destroyed as coarse particles fan out along the
wall in a single layer, exposing the small particles that
so far have been shielded from the central current. The
central current of departing water in this smallest section
is relatively weak, having spent itself in the preceding
sections. The upward current that remains separates the
small particles from the remainder of the material, with
preference for those of low specific gravity. Thus, the
fine, light particles are finally discharged up through
the vortex finder by a process of elutriation. The fine
and coarse refuse is discharged through the apex.
The specific gravity of separation of a hydrocyclone,
and hence the clean coal ash content, is regulated in
general by varying the dimensions of the discharge orifices.
For example, the clean coal ash content can be reduced by
decreasing the diameter of the vortex finder or increasing
the diameter of the underflow orifice. To achieve the
same result, the length of the vortex finder can be
decreased. Generally, the vortex finder length is not
changed, but the distance that it projects into the
conical section of the cyclone is varied by adding or sub-
tracting shims between a flange on the vortex finder and
the bottom of the overflow chamber. This has the same
effect as changing the length of the vortex finder.
Capacities of the units are affected by the diameter of
the vortex finder and limited by the diameter of the apex.
Generally, a single stage hydrocyclone system can produce
a clean coal essentially free of misplaced refuse; however,
a significant characteristic of the hydrocyclone that
detracts from its performance is that a substantial portion
of the low specific gravity particles report to the refuse
product. Therefore, two-stage treatment is recommended
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and is especially applicable for minus h inch or minus 3/8
inch raw coal. For example, the raw coal is first treated
in a primary hydrocyclone which produces a finished clean
coal product. The refuse is recleaned in a secondary
hydrocyclone. The clean coal from this secondary hydrocyc-
lone joins the clean coal from the primary unit to form
the final clean coal product; the refuse from the secondary
hydrocyclone is the final refuse product.
The separations that are obtained in a hydrocyclone
are not nearly as sharp as those that are characteristic
of the dense medium cyclone. Therefore, the hydrocyclone
is not applicable for difficult-to-clean coals or for
separations at low specific gravities. The hydrocyclone
may be especially applicable for treating minus 28-mesh
coal if the coal is not amenable to flotation. If fine
pyrite is present in the feed, the hydrocyclone is
reported to be superior to flotation for lowering the
sulfur content of the clean coal.
The coarser particles of an easy-to-clean coal with a
top size of % inch or 3/8 inch can be cleaned about as
efficiently in a two-stage hydrocyclone as on a concentrat-
ing table. However, the concentrating table cleans the
finer particles much more efficiently than the hydrocyclone
and, although the hydrocyclone takes up considerably less
floor space than the concentrating table, the large
quantities of water and power required for operation of
the hydrocyclone must be weighed by the preparation
engineer.
7.3.5.3 Wet Concentrating Tables—It is estimated
that 75,000,000 tons of metallurgical coal are cleaned
annually on tables in the United States alone. In recent
years, the trend has been toward cleaning of utility coal
which formerly was burned with little or no preparation in
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electrical power generating plants. Strict regulations
concerning SC>2 emissions have helped to increase the use
of tables to remove pyritic sulfur from raw coal before
the coal is burned.
Many modern coal preparation plants in which tables
are used feature dense media vessels to clean the coarse
fraction and froth flotation to clean the extreme fines.
The 3/8" x 0 or V x 0 raw coal is run across fixed sieves
separating at about 48-mesh, and the V" x 48-mesh fixed
sieve overflow goes to double-deck tables while the 48-mesh
x 0 underflow reports to flotation cells. This is a
simple flow-sheet and produces good results, so long as the
sulfur content of the 48-mesh x 0 fraction is not a problem
(the pyrite will float right along with the coal). This
problem can be overcome by sending the fixed sieve under-
flow to classifying cyclones ahead of the flotation. The
48-mesh x approximately 100-mesh cyclone underflow, which
contains free pyrite down to about 325-mesh, then rejoins
the V x 48-mesh fraction at the table distributor. The
tables will efficiently provide ash reduction through 100-
mesh while simultaneously rejecting free pyrite down to
325^mesh. In the meantime, the -100-mesh classifying
cyclone overflow has gone to flotation with most of the
sulfur already removed.
Today's modern wet concentrating tables are the
natural outgrowth of an evolutionary process that began
years ago. The introduction of suspended, multiple-deck
tables in the late 1950's and early 1960's by the Deister
Concentrator Company has been the latest significant
development in the manufacture of concentrating tables.
This has eliminated to a large extent two of the primary
disadvantages of concentrating tables, namely the need for
large amounts of floor space and the need for massive
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concrete foundation piers and flooring to absorb the impact
of the drive mechanisms. Figure 7-39 depicts the suspen-
ded, multiple-deck tables in their two most common
configurations.
The table employs the principle of flowing a mixture
of coal and water over a series of riffles which are
shaken rapidly to effect a separation of the coal by
particle size and specific gravity. Basically, the table
consists of a pair of steel channels upon which is mounted
a rubber-covered deck and a drive mechanism. The flat,
rhomboid-shaped deck is approximately 17 feet long on the
clean-coal side and 8 feet long on the refuse side. It
is supported in an essentially horizontal plane, but slopes
enough (perpendicular to the motion of the deck) so that
water fed along the upper long side will flow across the
table surface and discharge along the lower clean-coal
side. The deck is attached to a differential motion drive
which gives it a quick return conveying motion, moving
material lying on the table surface away from the drive end.
Attached to the rubber covering on the deck is a
system of rubber riffles tapering toward the refuse end of
the table and parallel to the direction of the conveying
motion. Standard body riffles are approximately \ inch
high at the drive end of the table. Between each set of
three or four body riffles are high (over 1 inch at the
drive end) "pool" riffles. These riffles form dams,
behind which stratification of the bed occurs. Low-density
particles ride over the riffles, reporting to the clean-
coal side- of the table; high-density particles are carried
behind the riffles by the differential-motion drive to the
refuse end of the table (see Figures 7-40 and 7-41).
At one corner of the long diagonal and above the deck
is a feedbox with a slotted bottom to spread the feed onto
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Source: Deister Concentrator Company, Inc.
J.J.DAVIS
A S S O C I ATE S
Typical Deister
Table Installations
Fiqure 7-39 DCN
184
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Figure 7-40
Rubber Riffles on a Concentrating Table
(
Figure 7-41
A Fully Loaded Table in Good Adjustment
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the deck. Beside the feedbox and along that side of the
deck is a trough^ having adjustable gates -through which
the flow of dressing water to the deck is distributed.
Because of the reciprocating action of the table and
the transverse flow of water, the pulp fans out immediately
upon contacting the table surface. The upward slope of
the table toward the refuse end, usually 1/8 to % inch
per foot, and the retaining effect of the pool riffles
cause the slurry to form a pool near the feedbox. In the
pool, the bed of material is several particles deep and
substantially above the standard riffles and becomes the
zone of primary stratification. In this zone the shaking
motion of the deck combined with the cross current of
water stratifies the particles by density, similar to the
action of a jig washer.
Without doubt, the most fundamental principle of the
table is the vertical stratification according to specific
gravity that occurs behind the riffles due to the differ-
ential shaking action of the deck. The particle:; that make
up the feed become arranged so that the finest and heaviest
particles are at the bottom and the coarsest and lightest
particles at the top. The smallest, heaviest particles
are carried out by table movement toward the refuse end at
a faster rate than coarse, heavy particles. The light-
gravity larger pieces ride on the top layer of particles
and flow on down the slope of the deck as a result of the
cross flow of wash water at right angles to the shaking
movement of the table. Since stratification and separation
of particles are not complete as a result of any one
riffle, a series of riffles is used, repeating the cycle
of stratification and hindered settling from riffle to
riffle, obtaining purer refuse products as the particles
fan out and progress forward and downward over the table.
186
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Conversely, the purer, cleaner coal is discharged at the
drive end of the table.
As graphically portrayed in Figure 7-42, successive
samples collected along the side and end of the table,
starting at the head-motion end, show a steady increase in
ash content and a steady decrease in the average particle
size for each individual specific-gravity fraction.
i—DRESSING WATER-i FEED
LOW GRAVITY CLEAN COAL
MIDDLING (HIGH SULFUR COAL)
Q HIGH GRAVITY REFUSE
Figure 7-42
The Distribution of Table Products
by Particle Size and Specific Gravity
187
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Concentrating tables are provided with a number of
adjustments which should be used to obtain the best
possible operation. Among these are: (1) speed, (2)
length of stroke, (3) feed rate, (4) amount and distribu-
tion of wash water, (5) water-to-solids ratio of the feed
pulp, (6) uniformity of feed, (7) riffle design, (8) side
tilt and (9) end elevation. The reciprocation of the deck
usually is 260 to 290 strokes per minute depending on the
characteristics of the raw coal and the feed rate. If
there are high percentages of refuse in the raw coal or if
the feed rate is high, an increase in the frequency is
required.
Closely related to the frequency is the amplitude.
The amplitude and frequency are varied to maintain the
mobility of the bed necessary for stratification while
retaining the coal on the deck long enough for proper
separation. In order to move large quantities of refuse
material along the deck, an amplitude as long as Ik inches
may be required. Conversely, the stroke may be less than
% inch long when coals containing high percentages of
near-gravity material are washed. The amplitude and fre-
quency of the stroke are decreased as the amount of near-
gravity material in the feed increases. A nominal 3/8 inch
to 0 coal would require a stroke amplitude of about 3/4
inch and frequency of 275 strokes per minute. Generally,
a fine feed will require a higher speed and shorter stroke
than a coarse feed.
The cross slope and amount and distribution of
dressing water to the table can be changed easily and
quickly to compensate for minor variations in feed rate
and composition. The cross slope is generally less than
5°, and the dressing water side of the table is higher than
the clean-coal side. The feed dilution (water to solids
188
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ratio) normally used on a table is 2:1. The quantity of
water used in the feed slurry varies, but the normal feed
dilution is 40% solids for a V x 0 size coal feed, and
may drop to 33% solids for 3/4" x 0 coal.
Perhaps the most important of all table adjustments
is the end elevation or the amount of upward inclination
of the deck measured along the line of motion from the
feed end to the discharge end. By creating a moderate
slope that the high specific gravity particles will climb
more readily than will the low specific gravity minerals,
the separation is greatly improved. The high specific
gravity minerals are forced to spread out in a thin, wide
band which allows much sharper cuts to be made between
clean coal, middling and refuse. The correct amount of
end elevation varies with feed size and is greatest for
the coarsest and highest gravity feeds. A nominal 3/8 inch
to 0 feed would require 3 to 4 inches of end elevation.
Table capacity varies with the size consist, the
percentage of reject contained in the feed and the washa-
bility of the table feed. Coarser feeds handle at higher
rates than do finer feeds; and feed rates will be limited
by the percentage of reject above 25%; and as the diffi-
culty of cleaning decreases, feed rates can be increased.
The majority of all installations in bituminous coal are
on 3/8" x 0, or %" x 0 or deslimed fractions of some top
size where, on coals of normal washing characteristics,
capacity per double-deck table is 25 tph feed, i.e., 12%
tph per deck. For 3/4" or %" top size, commonly handled
when cleaning steam fuels, capacity of 30 tph per twin-deck
table can be expected.
7.3.5.4 Fine Coal Launders and Jigs—Standard coal
washing jigs, as discussed in Section 7.3.4, often treat
the total size range of coal and retreatment of the smaller
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coal sizes is usually required. Although the fine coal
washers have nearly died out in this country, Roberts and
Schaefer is reintroducing a "fine coal jig". The Batac
jig was developed by Humboldt Wedag of Germany and incor-
porates features of both the Baum jig and the Japanese
Tacub jig. This jig has been discussed in detail in
Section 7.3.4. The unit is designed to clean primarily 2"
x 0 coal and it is hoped that the finer coal sizes will
not have to be reclaimed as with other types of jigs or
launders. At the moment, less than 6% of the intermediate
coal sizes are effectively cleaned using fine coal launders
or jigs and supporting data on the effectiveness of the
Batac jig is still incomplete.
7.3.6 Separation of Fine Size Coal
As indicated in Chapter 8, other than just pumping
away the black water from the plant, a number of methods
are used to remove the ultra-fine coal and refuse solids
from the recirculating water in a coal preparation facility.
However, only one system is successful in separating only
the salable coal from a -48-mesh size feed—froth flotation.
As noted in various portions of Section 7.3 and in Chapter
8, a number of systems or pieces of equipment either
concentrate or classify the finer sized particles for
feeding to the froth flotation process. Figure 7-43
highlights a number of these entities.
Froth flotation of fine coal is a unique cleaning
process when compared to every other separating system
discussed in that the flotation process does not utilize
the specific gravity difference between coal and refuse to
effect a separation. In fact, the flotation process is
not a physical process at all, but rather a chemical
process that depends upon the selective adhesion of air
bubbles to the coal particles and the simultaneous wetting
or water adhesion to the refuse solids. The adhesion of
190
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J.J.DAVIS
ASSOCIATES
Contributing
Equipment to the
Pine Coal Circuit
-------
the air bubbles to the coal particles causes the coal to
be buoyed up through the rather turbulent and foamy slurry
to the top where they can be removed (usually with wooden
paddles) as a concentrate while the wetted refuse particles
remain with the underflow and are removed to a settling
system. One type of froth flotation cell is depicted in
Figure 7-44. Figure 7-45 depicts the foamy coal-laden
"froth" at the top of a typical flotation cell and Figure
7-46 depicts a typical multi-cell froth flotation installa-
tion.
Froth flotation cells are upright trough type steel
tanks which have a central agitating device to create the
air bubbles. The fine coal slurry, usually from 4 to 12
percent solids, enters at one end in conjunction with a
frother reagent of one kind or another. The treated slurry
flows through several adjoining cells and the frother coal
(coal that is buoyed up) is decanted from the surface at
about 25% solids. The tailings or underflow continue to
migrate to the far end of the multi-cell where they are
removed with the bulk of the water to some type of a
recovery system (usually a static thickener). The concen-
trated coal solids are usually fed to a vacuum filter for
final recovery and subsequent dewatering.
The major factors affecting the flotation of coal
within the froth flotation process are:
particle size,
oxidation and rank of the coal,
pulp density,
pH and water characteristics,
flotation reagents and
equipment
192
-------
UPPER PORTION
OF ROTOR
DRAWS AIR DOWN
THE STANDPIPE
FOR THOROUGH
MIXING WITH PULP
DISPfRSER BREAKS AIR
INTO MINUTE BUBBLES
LARGER FLOTATION
UNITS INCLUDE FALSE
BOTTOM TO AID PULP FLOW
THE FLOTATION CONCEPT
Flotation selectively separates different
minerals by agitation, dispersion and gas
induction. An intimate mixture of air and
mineral-laden liquid is produced by dissemin-
ation of air throughout the liquid. Chemical
reagents are added which selectively form a
water-repellant coating on the mineral
particles to be floated. Millions of tiny bubbles
are created by the air/liquid mixture. The
coated mineral particles adhere to the
bubbles and are carried to the surface where
they are removed by simple displacement.
Frothing reagents increase bubble surface
tension, forming a firm mineral laden froth at
the pulp surface. Minerals which are not to be
floated are wetted and so remain in the pulp.
Either the floated or the depressed minerals
may be the valuable portion.
Source: WEMCO
Flotation is produced in one of two ways.
Many mechanical-pneumatic flotation
machines use external compressors to blow
air through the cells. This produces a turbulent
froth of relatively large bubbles. WEMCO
aeration is induced by a rotor that entrains
air in its vortex. This reduces turbulence to
a minimal level while providing maximum
dispersion of small bubbles.
J.J.DAVIS
ASSOCIATES
The Flotation
Concept
Figure 7-44 I DCN
193
-------
!
,
Figure 7-45
Coal Laden Froth
Figure 7-46
Typical Multi-Cell
Froth Flotation Installation
194
-------
Particle size is important from both mechanical and
economic considerations. As noted, the intermediate size
coal cleaning equipment can usually do a respectable
cleaning job down to 48-mesh. As a general rule, it is
more economical to clean coal by the standard specific
gravity method (Deister tables or dense media cyclones)
than by* froth flotation, down to the minimum sizes these
devices can efficiently handle. Consequently, even though
particles as coarse as 3/16 inch may be floated by froth
flotation, it is generally considered uneconomical. From
the mechanical side, the coarse sizes are more difficult
to handle due to the increased flotation rate (it takes
longer retention time in the flotation unit for the
coarse particles to be buoyed to the surface). The very
fine size coal, say below 150-mesh, is more difficult to
float than the 48 to 150-mesh, but to a lesser extent than
those exceeding 48-mesh in size. Figure 7-47 highlights
the floatability of coal based on particle size.
0)
4-1
&
0)
c
o
•rl
4J
0
FLOTATION RATE CURVE
14 28 48 100 200
Mesh
Figure 7-47
Floatability as a Function
of Particle Size
195
-------
The rank and oxidation of the coal entering the
flotation cells affects their floatability. Generally, low
volatile coals are easier to float than most high volatile
coals. Lignite is the least floatable form of coal. On
the other hand, a highly floatable coal will become diffi-
cult to float if it has become highly oxidized.
The percent of solids in the coal-water slurry (pulp
density) also affects the froth flotation. Pulp densities
may be found between 3 and 20 percent, with an approximate
average of 7 percent. The large variance in pulp density
is due to treating slurries with varying particle sizes.
As a general rule, the coarser the coal particles, the
higher the pulp density, and the finer the coal particles,
the lower the pulp density.
Both the recovery efficiency and the quality of the
froth product are directly affected by the quality of the
water in the coal-water slurry. Coal recovery is the
highest when the pH of the water is between 6 and 7.5.
The ash content in the float coal increases as the pH
value increases; however, the higher the pH value the lower
the percentage of pyrite in the float coal. The amount of
soluble salts in the water affects flotation results, but
little is known of their effect. Colloidal clays or slimes
in the water inhibit the flotation process. The clays or
slimes may be controlled by the proper use of chemical
agents in the flotation cells or by removing them ahead
of the flotation step.
The importance of using the proper amount and kind of
reagents is extremely critical to the flotation process.
There are three general classes of reagents: frothers,
collectors or promoters and modifying agents. The main
purpose of frothers (frothing agents) is to facilitate the
production of a stable froth, i.e., they must create a
196
-------
froth that will sustain itself long enough to buoy up the
coal particles and hold them on the surface until they can
be removed. The only substances which can be frothers are
ones which can change the surface tension of the water.
Examples of frothers are amyl and butyl alcohols, terpinol
and cresols. Kerosene, crude oil and various coal tars
are occasionally used, however, the choice of any frother
depends upon its availability, price and effectiveness on
the particular coal being treated.
The function of the collector or promoter reagent is
to promote contact between the coal particles and the air
bubbles by forming a thin coating over the particles
rendering them water repellent. The collector must be
selective, that is, it must coat only the coal particles;
it must not coat the refuse particles. Most of the collec-
tors used in the flotation of coal are both frothers and
collectors. Examples are MIBC (methyl isobutyl carbinol)
and kerosene. For most coals, a combination frother-
collector is generally all that is needed, including
oxidized or low rank coals.
The largest number of reagents used in the froth
flotation process are generally grouped under the heading
of modifying reagents. Most reagents of the category may
have several functions or varying functions under varying
conditions:
Depressing agents—are used to inhibit the
flotation of unwanted particles by coating them
so they will not attach themselves to the rising
air bubbles. Sodium and potassium cyanides are
effective depressants of zinc and iron sulfide
(pyrite) minerals.
Activating agents—are substances which so alter
the surface of a mineral that it may be filmed by
a collector or frother collector allowing it to
more readily attach itself to the rising air
bubbles.
197
-------
pH regulators—are used to govern the degree of
alkalinity or acidity of the flotation slurry.
Dispersing agents—are used to remove the slimes
or clays by acting as a flocculant, and thus
aiding in their settling within the flotation
cell.
As noted earlier, the removal of ash and pyrite from
the coal-water slurry presents a dichotomy: as removal of
ash increases, the percent of pyrite in the clean coal also
increases. With the increased emphasis upon pyrite removal
and the continuing requirements for a low ash coal, the
U.S. Bureau of Mines has developed under direction of
A. W. Deurbrouck, and patented, a unique two-stage froth
flotation process to remove the pyritic sulfur.
The process consists of a first stage, standard coal
flotation step, in which high ash refuse and coarse or
shale associated pyritic sulfur are removed as tailings.
The first stage coal froth concentrate is then repulped
in fresh water, pH is maintained below 7, and a coal
depressant, a pyrite collector and a frother are added in
a second stage to float any of the pyritic material carried
over into the first stage froth; the second stage underflow
is left as a final clean coal product.
Laboratory and pilot plant flotation tests with coals
from various coal beds throughout the Appalachian region
showed that pyritic sulfur reduction of up to 80% could be
achieved by using this technique.
198
-------
REFERENCES AND/OR ADDITIONAL READING
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Blankenship, R.E., "Operational and Environmental Features of Virginia
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. April 1973
Burdon, R.G.; Booth, R.W.; Mishra, S.K., "Factors Influencing the
Selection of Processes for the Beneficiation of Fine Coal",
Austrailia, Australian Coal Conference
Capes, C.E.; Mcllhinney, A.E.; McKeever, R.E.; Messer, L., "Appli-
cation of Spherical Agglomeration to Coal Preparation", Australian
Coal Conference
Charmbury, H.B., "Mineral Preparation Notebook", Pennsylvania State
University
Coal Age, "Coal Preparation and Unit-Train Loading", July 1972
Coal Age, "The Coming Surge in Coal Preparation", January 1976
Coal Age, "Consol Preparation Confirms Coal Quality", October 1972
Coal Age, "Multi-Stream Coal Cleaning System Promises Help With
Sulfur Problem", January 1976
199
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Coal Age, "Peabody Pioneers in Coal Handling & Preparation", Model
Mining Issue, October 1971
Coal Age, "U.S. Steel Coal Preparation", Model Mining Issue,
October 1973
Cook, L., "Practical Application of Hydraulic Mining at Rahui Buller
Coalfield", Paper 31, Mining Conference, School of Mines & Metallurgy,
University of Otago, May 1953
Cooper, Donald K., "Coal Preparation - 1974", Mining Congress Journal,
February 1975
Dahlstrom, D.A.; Silverblatt, Charles, "Production of Low Moisture
Content Fine Coal Without Thermal Drying", Mining Congress Journal,
December 1973
Daub, Charles H., "The Oneida Plant", Mining Congress Journal, July 1974
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
Dell, C.C.; Jenkins, B.W., "The Leeds Flotation Column", United Kingdom
Australian Coal Conference
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Deurbrouck, A.W.; Palowitch, E.R., "Performance Characteristics of Coal
Washing Equipment, Concentrating Tables", U.S. Bureau of Mines
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Deurbrouck, A..; Hudy, J. JR., "Performance Characteristics of Coal-
Washing Equipment, Dense - Medium Cyclones", U.S. Bureau of Mines
Report of Investigations #7673, 1972
Deurbrouck, A.W., "Performance Characteristics of Coal-Washing Equip-
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Deurbrouck, A.W.; Hudy, John, Jr., "Performance Characteristics of
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200
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Deurbrouck, A.W., Steam as a Coal Dewatering Aid During Vacuum
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Bureau of Mines Report of Investigations #6718, 1966
Deurbrouck, A.W., "Survey of Sulfur Reduction in Appalachian Region
Coals by Stage Crushing", U.S. Bureau of Mines Report of Investi-
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Deurbrouck, A.W., "Washing Fine-Size Coal in a Dense-Medium Cyclone",
U.S. Bureau of Mines Report of Investigations #7982, 1974
Kokunin, A.V.; Onika, D.G., "Hydraulic Underground Mining", Translated
for Branch of Bituminous Coal Research, Division of Bituminous Coal,
U.S. Bureau of Mines
Ellison, William; Heden, Stanley D.; Kominek, Edward G., "System
Reliability and Environmental Impact of SO Processes", Coal Utili-
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October 1974
Environmental Protection Agency, "Air Pollution Technical Publications
of the Environmental Protection Agency, Research Triangle Park, North
Carolina, July 1974
Foreman, William El; Lucas, J. Richard, "Current Status of Hydro-
Cyclone Technology", Mining Congress Journal, December 1972
Foreman, William E., "Impact of Higher Ecological Costs and Benefits
on Surface Mining", American Mining Congress Coal Show, Detroit,
Michigan, May 1976
Geer, M.R.; Yancey, H.F., "Evaluation of Washery Performance", U.S.
Bureau of Mines Report of Investigations #8093, 1962
Goodridge, Edward R., "Duquesne Light Maximizes Coal Recovery at its
Warwick Plant", Coal Age, November 1974
Gospodarka, Gornictwa, "Possibilities of Mechanical Preparation
Underground", 1956 No. 4
Grimm, Bobby M., "Preparation Plant Corrosion Cost", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
Gvozdek, G.; Macura, L., "Hydraulic Mining in Some Deep Pits in
Czechoslovakia", Translated by National Coal Board (A 1683), Uhli
#12, December 1958
201
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Hake, W.D., "Application and Performance of Batac Jig Processing
Fine Coal at Old Ben Mine 26, Sesser, Illinois", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
Hall, A.W.; Martin, J.W.; Stewart, R.F.; Poston, A.M., "Precision
Tests of Neutron Sulfur Meter in Coal Preparation Plants", U.S.
Bureau of Mines Report of Investigations #8038, 1975
Henderson, G.S.; Andren, A.W.; Harris, W.F.; Reichle, D.E.; Shugart,
H.H.; Van Hook, R.I., "Environmental Assessment of SO and Trace
Element Emissions from Coal Utilization", Coal Utilization Symposium-
Focus on SO. Emission Control, Louisville, Kentucky, October 1974
Hudy, J., Jr., "Performance Characteristics of Coal-Washing Equipment",
U.S. Bureau of Mines Report of Investigations #7154, July 1968
Hulett, L.D.; Carter, J.A.; Cook, K.D.; Emery, J.F.; Klein, D.H.;
Lyon, W.S.; Nyssen, G.A.; Fulkerson, W.; Bolton, N.E., "Trace
Element Measurements at the Coal-Fired Allen Steam Plant—Particle
Characterization", Coal Utilization Symposium-Focus on SO Emission
Control, Louisville, Kentucky 1974
Humboldt-Wedag, "Manufacturers Brochures", Cologne, Germany
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Provence Coalfield", France, Australian Coal Conference
Irminger, P.F.; Giberti, R.A., "Desulfurization Technology to Meet
the Power Demand", NCA/BCR Coal Conference and Expo II, October 1975
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracite in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Jeffrey Mining Machine Co., "Jeffrey Mining Machine Company: Manu-
facturers Information", Columbus, Ohio
Jenkinson, D.C., "Some New Coal Preparation Developments in the United
Kingdom", National Coal Board Bulletin M4-B148
Johnson Division, UOP Company, "Brochure - 1975"
Johakin, J., "Solving the SO Problem—Where We Stand with Application
and Costs", Coal Age, May 1975
202
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Kent, James A. (Editor), "Riegel's Handbook of Industrial Enchistry
(7th Ed.)", Van Nostrand Reinhild Publishing Company, New York, 1974
Kester, W.M., "Magnetic Demineralization of Pulverized Coal"
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
Kollodiy, K.K.; Borodulin, V.A.; Nazarov, P.G., "Processing of Coal
Mined by the Hydraulic Method", Ugol #9, 1974 (Translated by
Terraspace)
Korol, Dionizy, "Influence of Hydraulic Getting on Mechanical Coal
Preparation", Przeglad Gorniczy, Year 12 #12, December 1956
(National Coal Board Translation Section)
Kuti, Joe, "Longwall vs. Shortwall Systems", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania, May 1975
Lamella, (Sala of Sweden), "Theory and Design of the Lamella Gravity
Settler", Technical Bulletin #105, May 1975
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Llewellyn, Robert L., "Coal Preparation", Elements of Practical Coal
Mining, Seeley W. Mudd Series, American Institute of Mining,
Metallurgical and Petroleum Engineering, Inc., New York, 1968
Lotz, Charles W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Lowman, Stephen G., "Westmoreland Coal's Bullitt Plant Upgrades Steam
Coal Quality", Coal Age 1973
Lowry, H.H. (Editor), "Chemistry of Coal Utilization", John Wiley &
Sons, Inc., New York, New York, 1963
Lovell, Harold L., "Sulfur Reduction Technologies in Coals by Mechani-
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Manwaring, L.G., "Coarse Coal Cleaning at Monterey No. 1 Preparation
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203
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Markley, R.W.; Cavallaro, J.A., "Efficiency in Cleaning Fine Coal by
Froth Flotation—A Cell by Cell Pilot Plant Evaluation", Mining
Congress Journal, June 1974
Mathur, S.P., "Hydraulic Mining of Coal", Journal of Mines, Metals and
Fuels, May 1972
McNally-Pittsburg Manufacturing Corporation, "Coal Cleaning Plant
Prototype Plant Design Drawings", Department of Health, Education and
Welfare Contract 22-68-59
McNally-Pittsburg Manufacturing Corporation, "Coal Preparation
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Technology
Mengelers, J.; Absil, J.H., "Cleaning Coal to Zero in Heavy Medium
Cyclones", Coal Mining and Processing, May 1976
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Using Concentrated Second-Stage Pulp", U.S. Bureau of Mines Coal
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Bureau of Mines Technical Progress Report #51, February 1972
National Coal Board, "Hydraulic Transport of Coal at Woodend Colliery",
September 1961
Nirtsiyev,"Hydraulic Extraction of Coal in the Donetz Basin Izdatel
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Nunenkamp, David C., "Survey of Coal Preparation Techniques for
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Parkes, David M; Grimley, A.W.T., "Hydraulic Mining of Coal", American
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Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
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204
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Poland, "Beneficiation of Coal Fines by Selective Flocculation",
Australian Coal Conference
Protopapas, Panayotis, "A Report in Mineral Processing", Department of
Applied Earth Sciences, Stanford University, 1973
Protsenko, I.A., "The Technology of Beneficiation and Dewatering of
Coal Mined by the Hydraulic Method", Questions Regarding the Hydraulic
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Roberts & Shaefer Company, "Manufacturers Information Booklets",
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Roberts & Schaefer Company, "Design & Cost Analysis Study for Proto-
type Coal Cleaning Plant'!, August 1969
Roberts & Schaefer Company, "Research Program for the Prototype Coal
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Schuhmann, Reinhardt, Jr., "Metallurgical Engineering, Vol. I,
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205
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Sokaski, M.; Sands, P.P.; Geer, M.R., "Use of a Sieve Bend and a
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Wemco Division, "Manufacturer's Catalog", Envirotech Corporation
Sacramento, California, 1974
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206
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Zimmerman, R.E., "Batac Jig - A New Improved Baum Type Jig for Cleaning
Coarse and Fine Sizes of Coal", American Mining Congress Coal
Convention, May 5-8, 1974
207
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THIS PAGE INTENTIONALLY LEFT BLANK
208
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8. PRODUCT DEWATERING AND DRYING
8.1 OVERVIEW
Removing water from clean coal and refuse products is
a major coal preparation problem, second only to the
removal of pyrite. Excessive moisture in the coal and
refuse leaving the plant is an undesirable impurity for
numerous reasons, i.e., the moisture:
compounds the handling and haulage problems of
the coal and refuse,
increases the transportation costs of the clean
coal and the refuse,
reduces the effective Btu content of the clean
coal,
causes undue absorption of energy during the
combustion process and
renders the coal undesirable for coking.
Clean coal and refuse coming from a wet cleaning unit
are usually accompanied by large volumes of water which
must be removed as the product is sized and the heavy media
removed (if media are used) prior to additional processing.
Provisions for dewatering or for dewatering and drying
clean coal and refuse are, therefore, a necessary part of
wet cleaning plants. Drying of the ROM coal feed may also
be necessary in a dry cleaning plant if the moisture
content of the raw coal is not low enough to permit air
tabling.
209
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The product dewatering and drying module is defined as
all activity relating to removing water from the clean coal
and refuse products. This module is highlighted in Figure
8-1.
8.2 METHODOLOGY
The removal of moisture from coarse size coal is
relatively simple, while the removal of water from 10-mesh
coal or finer is a major problem usually requiring an
individual solution at each cleaning plant.
There are a number of methods that are used in the
dewatering of coal and refuse and in the dewatering and
drying of coal. These dewatering methods may be generally
grouped into five categories:
natural drainage,
screening,
centrifugal dewatering, >
thickening and filtering and
heat drying.
In practice, considerable overlapping of applications occur
among these dewatering techniques.
8.2.1 Natural Drainage
Natural drainage by the use of hoppers and bins has
been practiced for years, but has been largely replaced by
the sizing and dewatering shakers or vibrating screens.
Today, natural drainage is usually practiced only on the
coarse sizes of coal and refuse. The products are gener-
ally delivered to specifically designed bucket elevators
and bins where the surface moisture is allowed to drain
away (see Figure 8-2). Natural drainage is generally rapid
and complete for coal coarser than Jj inch. On the other
210
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COARSE
REFUSE
UNDER
OVER
1.
PLANT FEED
PREPARATION
SIZE REDUCTION
2
RUN OF MINE STORAGE
3
2.
RAW COAL
SIZING
RAW COAL
SEPARATION
4.
PRODUCT
DEWATERIN6 WATER
s.
PRODUCT STORAGE
AND SHIPPING
J.J.DAVIS
ASSOC I ATE S
Preparation Plant
Modules
Figure 4-2 I DCN
211
-------
hand, coal fines and clay particles greatly increase the
necessary time for complete drainage.
Natural drainage is usually used for preliminary
dewatering of the coarse refuse in the modern preparation
plant and is often accomplished by utilizing drainage
conveyors and bucket elevators. In most installations the
conveyors are inclined, and the conveyor speed is timed to
allow the natural drainage or to at least provide a high
degree of dewatering prior to further dewatering by means
of vibrating screens. Where vertical elevation is desired,
perforated bucket elevators are usually employed (see
Figure 8-2).
The natural drainage process by means of conveyors,
bucket elevators and hoppers may reduce the surface mois-
ture content of the coarse coal or refuse to 5 or 6 percent
under normal operating conditions.
8.2.2 Screens
Fixed screens, shaking screens and vibrating screens
are often employed for dewatering coal and refuse.
Screens are a natural choice for the initial dewatering
operation because of their ease of use, their ability to
size the coal simultaneously, their maximum retention of
the particles which insures adequate rinsing for media
recovery and their relative low cost. A typical vibrating
screen installation is shown in Figure 8-3.
Screens are commonly used to dewater coal and refuse
of all sizes. However, when the shaking screen is used
for dewatering coals smaller than 3/8 inch or ^ inch, the
screen capacity decreases so rapidly that an excessive
screen length is required or a number of screens must be
used to dewater any considerable tonnage. The high speed
shaking screens can be successfully used to dewater plus
212
-------
Figure 8-2
Natural Drainage via a Bucket Elevator
Figure 8-3
Typical Vibrating Screen Installation
213
-------
3/4 inch to plus h inch bituminous coals to a final sur-
face moisture of 3%. Normally, however, high speed shakers
are operated so as to give a final surface moisture in the
range of 5 to 10%. The minus 28-mesh material'is generally
removed in this process and must be further dewatered or
sent to the waste dump.
The particle movement and high capacity dewatering
effect of the shaking and vibrating screens are achieved
by high intensity vibrations and by the continuous tumbling
of the product particles on the screen surface owing to
the opposition of the screening surface to their forward
flow. The only difference between the vibrating screens
used for sizing and the vibrating screens used for dewater-
ing is that in the dewatering operation the screens are
used at less steep angles than when used strictly for the
sizing operations. In general, the vibrating screens will
yield higher capacities in dewatering operations than will
shaker screens because greater energy may be imparted
directly to the particles through the increased amplitude
available in the vibrating screen.
The vibrating and shaking screens used in dewatering
coal and refuse may be selected by the use of standard
screen formulas (see Chapter 7), but the surface moisture
of the product requires considerable additional attention
before the final selection process is completed.
As the surface moisture of the coal increases from the
bone dry state, a point is reached where the coal particles
begin to adhere to each other due to the surface tension
of the moisture film. As this point is reached, the fine
particles stick to the oversized particles and begin to
ride over the screen, resulting in poor screen efficiency.
As the surface moisture continues to increase, another
214
-------
point is reached where the damp particles wet the wire on
the screen surface and binding commences. (As the wire
becomes coated with a film of moisture, the fine particles
adhere to them. As the process continues, the screen
apertures are progressively closed off by a blanket of
material until, ultimately, screening ceases.)
The residual surface moisture of coal is usually
considered to be a function of the surface area of the
coal, although many other factors may contribute. If we
assume that the surface moisture is in direct proportion
to the surface area, then the finer sizes having the
greater surface area for a given weight will hold the most
water. For example, the surface moisture of 1% inch x %
inch coal would be lower than the surface moisture of %
inch x 0 coal if measured in comparable environments. How-
ever, the actual surface moisture depends upon the type of
coal, the size distribution of the particles, the effi-
ciency of the preceding screening, the ash content, the
tonnage handled, the retention time on the screen, the
interruptions in the screen surface and whether the product
is from the top or the bottom deck of the screen.
The dewatering screen selections are based on handling
a bed depth of material thin enough to be free draining.
The depth of the product on the screen is a function of the
size of the particles being dewatered since the smaller the
average particle size, the more difficult it is to drain
the bed and, therefore, the thinner the bed must be. (The
presence of the fine coal particles tends to fill the voids
and hold the water.)
Coarse coal may be sized and dewatered on the same
screen, but fine coal is not usually sized at this point
since the primary purpose of the screen is to retain the
salable coal solids while removing the water.
215
-------
When dewatering the fine coal on screens, the openings in
the screen surface are usually very small (\ mm to % mm)
and it is necessary to provide sufficient screen area to
pass the water. Fine coal has a tendency to pack, stratify
or to form a blanket or a cake. Better dewatering can be
obtained if the bed is periodically disturbed. In order
to mix up the bed of coal, cross dams are usually used on
the screen surface. Cross dams force the coal to climb
over the dam, making the bed more porous and permitting the
free drainage of water. On the other hand, some operators
use a water spray to break up the bed of coal or in con-
junction with the cross dams.
The capacity of fine coal dewatering screens is
influenced by the amount of water in the feed. If the
amount of water is too great, the high entrance velocity
resulting will cause the coal to flush down the deck,
reducing the screen area available for dewatering. Under
these conditions the surface moisture of the dewatered
coal will be very high and, under extreme conditions, free
water may be discharged with the coal. In order to prevent
excessive surface moisture of the dewatered product, the
amount of water admitted with the feed must be limited.
Tables 8-1, 8-2, 8-3, 8-4 and 8-5 give the capacity of coal
dewatering screens at various sizes of product and show the
maximum amount of water that can be admitted with the feed.
If the free water with the coal will exceed the amount
indicated, a stationary sieve ahead of the screen must be
used to reduce the incoming water.
8.2.2.1 Special Purpose Screens for the Heavy Media
Process The heavy media process (discussed in detail in
Chapter 7) is a method of cleaning coal based on the diff-
erences in specific gravity between coal and its impurities.
The raw pre-wetted coal is fed to a separatory vessel
216
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Table 8-1
TPH Capacity of Vibrating Screens
Dewatering Presized Coal at V
Scr««n
Width (Ft.!
3
4
5
6
7
8
Maximum Water
with F««d (GPM)
750
1050
1350
1650
1950
2250
Six* of Coal
V V '/
/« * /«
60
84
108
132
156
180
1'/«*'/<
65
91
117
143
170
195
2* '/«
75
105
135
165
195
225
3*'/4
80
112
148
180
215
248
4x'/«
90
126
162
198
234
270
5 ic V,
95
133
171
209
247
285
6*'/a
100
140
180
220
260
300
Table 8-2
TPH Capacity of Vibrating Screens
Dewatering Coarse Presized Coal at ^
mm
Scr«*n
Width (Ft.)
3
4
5
6
7
8
Maximum Water
with F..d (CPM)
350
490
630
770
910
1050
Six* of Coal
V,. x '/„
45
63
81
99
117
135
V, « '/«
50
70
90
110
130
150
1V«x'/,
55
77
99
121
143
165
1 •/,«•/„
60
84
108
132
156
180
2'/« x V.
65
91
117
143
170
195
2V,*'/,.
70
98
126
154
182
210
y*>*\
75
105
135
165
195
225
4*V,
80
112
148
180
215
248
Table 8-3
TPH Capacity of Vibrating Screens
Dewatering Fine Coal at ^ mm
Scr««n
Width (Ft.)
3
4
5
6
7
8
Maximum Water
with F««d (GPM)
170
230
290
350
410
470
Six* of Coal
1x0 V, x 0
35 30
49 42
63 54
77 66
91 78
105 90
V.xO
27
38
50
60
71
82
V,. x 0
25
35
45
55
65
75
'/ixO
22
32
40
49
58
67
VuxO
20
28
36
44
52
60
V.«0
15
21
27
33
39
45
lOMxO
12
17
22
27
32
37
217
-------
Table 8-4
TPH Capacity of Vibrating Screens
Dewatering Fine Coal at % mm
ScrOOII
Width (Ft.)
3
4
5
6
7
8
Maximum Wafer
with F..d (CPM)
275
385
495
605
715
825
Sis* of Coal
t xO
46
65
83
102
120
139
'/,xO
42
59
76
93
110
127
V.xO
37
52
67
83
97
113
'/,. x 0
35
49
63
77
91
105
V4xO
30
42
54
66
78
90
V,.xO
27
38
50
60
71
82
'/, xO
22
32
40
49
58
67
lOMxO
17
24
31
38
45
52
Table 8-5
TPH Capacity of Vibrating Screens
Dewatering Fine Coal at 1 mm
Scroon
Width (Ft.)
3
4
5
6
7
8
Maximum Watar
with Faad (GPM)
550
770
990
1210
1430
1650
Sis* of Coal
1x0
49
68
88
107
127
145
V,xO
45
63
81
99
117
135
V.xO
40
56
72
86
104
120
V,.xO
37
52
67
83
97
113
V«xO
31
45
58
72
85
97
'/..xo
30
42
54
66
78
90
V.xO
25
35
45
55
65
75
lOMxO
20
28
36
44
52
60
containing a suspension of finely ground media (usually
magnetite, Fe304) and water creating a synthetic specific
gravity which is maintained at a point between the specific
gravity of the coal and the specific gravity of the refuse.
This synthetic specific gravity will allow the coal to
float and will permit the refuse to sink.
To help illustrate the screens used in a heavy media
system, Figure 8-4 outlines a typical installation. Ahead
of the heavy media vessel, vibrating screens are used for
pre-wetting the feed and removing the fines. (Refer to
218
-------
dp
J.J.DAVIS
ASSOC I ATES
Screens Used in
a Typical Heavy
Media System
Figure 8-4 [ DCN
OMi
I
Tm - ii»oc>t«
11* CUM COI1
ciciim
J-"»'"«I"-«'i! .11
-------
Figure 8-4.) (1) Pre-wetting the incoming coal controls
the amount of water introduced into the heavy media vessel
and assists in the maintenance of the desired specific
gravity in the vessel. Removing the fine material ahead
of the vessel prevents contamination of the separating
media with fines. Fines have a tendency to remain in
suspension which adversely affects the specific gravity.
Following the heavy media vessel, the sink, float and
middling products (if recovered) are handled separately to
remove the water and to recover the media riding on the
product particles. A media recovery screen (2) drains the
media, washes and then dewaters the coal, middlings or
refuse. In order to perform these three operations, 16
foot or longer screens are usually selected, although in
some installations two shorter screens are used in tandem.
The drain section is usually the first 4 to 6 feet at the
feed end of the screen and the media drained off at this
point may be returned directly to the vessel since it is
of full strength. Following the drain section, the product
is washed using spray water and the media recovered is
concentrated before being returned to the heavy media
system. (3) Approximately 4 to 6 feet of screen length is
used for washing with 1^ to 3 GPM of spray water used per
ton of coal. The remaining length of the screen is used
for dewatering the product.
Media recovery screens are selected on the basis of
the bed depth that can be successfully drained and rinsed.
Table 8-6 shows the capacity of typical media recovery
screens. The tonnages indicated are maximum feed rates for
average media recovery. The values shown in Table 8-6
should be increased by approximately 30% if the media
recovery screen is used for refuse because of the reduced
volume of material per weight (water) and because the
refuse tends to drain more quickly.
220
-------
Table 8-6
TPH Capacity of Single Deck Low-Head Media
Recovery Screens at h mm
Six* of
Scr««n (Ft.)
3x 16
4x 16
5x 16
6x 16
7x 16
8x16
Feed Size
V."xl/amm
16
22
28
35
42
48
7/u"xlOM«»h
25
35
45
55
65
75
'/«" x '//
32
44
57
70
83
95
I"*1//
34
48
61
75
89
102
r//x'//
36
51
65
80
95
110
2"x1//
43
60
78
94
112
130
3"x'/«"
52
73
94
115
136
157
4"x'//
60
85
110
135
170
210
5"xV,"
80
110
140
170
200
230
6"x1//
85
118
151
185
218
250
8.2.2.2 Special Purpose Combination Screens (Inter-
mediate and Fine Size Coal Circuit) In some cases, special
combination sizing, dewatering and desliming screens may
receive the fine coal feed coming from concentrating
(Deister) tables. These screens are usually of the double
deck variety with the top deck arranged to make a separa-
tion at 10-mesh, 1/8 inch, 5/32 inch or 3/16 inch round.
The oversize from the top deck is usually set at ^ mm
separation size and the over product is routed to a
centrifuge prior to going to the heat dryer. The undersize
from the bottom deck is thickened, filtered and recovered
or disposed of in a settling pond.
Horizontal 16 foot screens are usually selected for
this application. Either deck may be the limiting deck
(capacity) depending upon the separation and the analysis
of the feed. Table 8-7 gives the capacities of typical
screens for various operating conditions. At least one
row of sprays is recommended for the top deck to break up
the cake, and at least three rows on the bottom deck.
Blinding and flooding of the bottom deck are typical in
this application and the screens must be watched carefully.)
221
-------
Table 8-7
TPH Capacity of Combination Sizing, Dewatering and
Desliming Screens Handling 3/8 x 0 or 1/4 x 0 Coal
Si so of
Screen (Ft.)
3x16
4x 16
5* 16
6x16
7x16
8x 16
Top Deck
Screen Cloth Opening
.10 x 21/,.©
37
52
67
82
97
110
.125 it 21/,.
41
57
73
90
106
122
.1875x3'/,.
56
78
100
123
145
165
Approx.®
Surface
Moisture (%)
11-17
11-17
11-17
11-17
11-17
11-17
Bottom Deck
Feed
.10x0 '/. xO
19 21
26 30
34 38
41 47
48 55
56 64
'/,.*0
24
33
43
52
62
71
Approx.®
Surface
Moisture (X)
26-32
26-32
26-32
26-32
26-32
26-32
(1) Called 10 mesh by some operators. the overproduct is increased.
(2) Surface moistures depend upon the analysis of the (3) Indicated capacity is only approximate. Use screen
overproduct from the deck and the type of coal. formula for wet screening to determine area re-
Surface moisture will decrease as the top size of quired. Bed depth may be the limiting factor.
8.2.2.3 Special Purpose Solid Recovery Screens All
wet process preparation plants use large quantities of
water which are eventually reused or discarded. This water
contains fine coal or refuse solids which must be removed
if the water is to be reused or discarded. In the past,
coal operators used settling ponds or abandoned mines to
settle the fine coal solids and then either reused the
water or discharged it into streams. Modern practice in
closed circuit preparation plants is to install machinery
for collecting the solids from the plant slurry and re-
using the water. The equipment used to clarify the slurry
normally consists of rakes, spiral or bowl classifiers,
drag tanks, settling cones, centrifuges, cyclones and
filters. A special purpose vibrating screen may be used
as an auxiliary to these solids-recovery units. The screen
(when used) usually follows the thickening unit and pre-
cedes the centrifuge or filtering units. Under certain
222
-------
conditions, solids-recovery screens are used alone and the
underflow from the screen is sufficiently clarified for
reuse in the plant.
Most coals are excellent filtering agents, and this
phenomenon is used in recovering solids on a vibrating
screen. In order to form a deep filtering bed on a solids-
recovery screen, it is necessary to use cross dams or to
run the screen uphill. Figures 8-5 and 8-6 depict typical
solids-recovery screen applications. The thick layer of
coal created on the screen deck acts as its own filter by
trapping further solids introduced with the feed. Solids-
recovery screens usually have openings of \ mm, or the
first section with h nun and the balance with h nun openings.
These screens have heavier deck construction than standard
screens because of the increased load of coal and water
carried on the deck.
Solids-recovery screens can be operated by either
forming a bed with k inch x 0 coal or refuse and then
depositing the slurry on the bed 6 to 8 feet down the
screen or by using the slurry to form the bed and then
recirculating the fines and water that initially pass
through the screen as the second layer on the previously
formed bed. In the latter case, the slurry is usually
sent to a secondary cyclone for thickening before it is
returned to the screen. In order to form a filter bed,
15 to 20% of the solids in the slurry must be larger than
the screen openings and the feed should contain 40 to 60%
solids. Refuse is used as a filter bed if the solids
recovered contain high ash and are to be discarded as ref-
use. Tables 8-8 and 8-9 show capacities of typical solids
recovery screens.
223
-------
Figure 8-5
Solid Recovery Screen Applications
224
-------
J.J.DAVIS
ASSOCIATES
RUNNING THE
SCREEN PRODUCT
UPHILL
Figure 8 6. I DCN
225
-------
Table 8-8
TPH Capacity of Solids Recovery Screens Receiving
Only Fine Coal Feed 1 mm or ^ mm x 0
Six* of
Scr..n (Ft.)
3x 16
4x 16
5x 16
6x 16
7x 16
8x 16
Openings in
Scr..n Surface (MM.)
'/«
V,
V,
'/«
V,
V,
Max. TPH of
1 mm. x 0 Feed
8
12
16
20
24
28
Max. TPH of
Secondary Cyclone
Underflow to Top Bed
V, to 1
1 to IV,
IV, to 2
2 to 2V,
2V, to 3
3 to 3V,
Estimated Surface
Moisture of Cake
22 to 28
22 to 28
22 to 28
22 to 28
22 to 28
22 to 28
Table 8-9
TPH Capacity of Solid Recovery Screens Receiving k" x 0
Coal and Thickened Fine Coal Slurry
Siie of
Screen (Ft.)
3x 16
3x 16
4x 16
4x 16
5x 16
5x 16
6x 16
6x 16
7x 16
7x16
8* 16
8x 16
Openings in
Screen Surface (MM.)
'/<
4' - V, feed end
followed by V«
V,
4' - % feed end
followed by %
'/,
4' - V, feed end
followed by '/«
'/«
4' - V, feed end
followed by %
%
4' - V2 feed end
followed by V,
'/«
4' - V, feed ond
followed by %
Max. TPH
V," x 0 Feed
12
13
16
19
21
24
25
30
30
35
35
40
Max. GPM Water
with Feed
150
200
200
250
250
300
300
350
350
400
400
450
Mux. TPH of
Cyclone Underflow
3V,
3Va
4'4
4V,
6
6
7V,
" 7V,
8V,
8J4
10'
TO
Estimated Surface
Moisture of Cake
20 to 25
18 to 23
20 to 25
18 to 23
20 to 25
.
18 to 23
20 to 25
18 to 23
20 to 25
18 to 23
20 to 25
18 to 23
226
-------
8.2.2.4 Special Purpose Fixed Screens Screens,
particularly those used for fine sizing, dewatering and
recovery of dense media, comprise a significant part of
the cost of coal preparation plants. Their capacity is
low (as indicated in Tables 8-1 through 8-9) in relation
to their floor space requirement. In addition to their
initial cost, screens add proportionately to the building
cost. The use of screens is increasing because of the
increased proportion of the fines in the washery feed and
the present trend toward recovering the finest sizes of
coal. Thus, any improvement in the capacity of screens
contributes substantial reductions in plant capital costs
as well as increasing the throughput capacity of the plant.
The sieve bend is a curved stationary sieve developed
by the Dutch State Mines. Figure 8-7 depicts a typical DSM
sieve bend. The patented design of these units evolved
from development work initiated in the Netherlands during
the early 1950"s. The screens were first used in dewater-
ing and coarse sizing applications. Today, the sieve bend
is usually placed ahead of the vibrating screen in order
to reduce the water load on the screen, although occasion-
ally it is used as the only sizing and dewatering device
for certain operations.
The sieve bend is a truly fixed ^screen having no
vibrating or moving parts. The sieve bend operates without
power if it is positioned at a lower elevation than its
source feed. The fluid action of the feed and the force of
gravity combined with the centrifugal force developed from
its curvilinear shape aid in its operation (see Figure
8-8).
The sieve bend is usually made of Bixby-Zimmer or
Wedgewire screen surface with the openings in the surface
at right angles to the flow of the feed down the screen.
227
-------
Fiaure 8-7
Sieve Bend
Photo courtesy of Dorr-Oliver, Incorporated
DSM Screentm is a registered trademark
of Dorr-Oliver, Incornorated
228
-------
FEED
MOISTURE & FINES
DEWATERED-
PRODUCT
J.J.DAVIS
ASSOCIATES
MANAGEMENT ENQINEERS
SCHEMATIC DIAGRAM
OF A SIEVE BEND
Figure 8-8.
DCN
229
-------
The feed slurry is introduced tangentially to the sieve
bend by the means of a feed box. The feed flows by gravity
down the arc of the surface and is discharged at approxi-
mately a 45 degree angle from the sieve bend. The actual
separation obtained is approximately one-half the opening
size in the surfaces.
The sieve bend is an inefficient device for sizing
and dewatering compared to the vibrating screen. The over-
product will have a considerable amount of free water and
the separation is not exact. The sieve bend will only
function properly within a relatively narrow capacity
range. A sieve bend used in conjunction with a vibrating
screen will give a higher efficiency and will dewater
better than a vibrating screen alone. The sieve bend is
frequently used ahead of the vibrating screen as a replace-
ment for the conventional stationary sieve in the flume in
order to relieve the load on the vibrating screen. For
approximate duplication of dewatering results, a screen .
used in conjunction with the sieve bend can be 2 to 4 feet
shorter than a vibrating screen used alone.
A new type of vortex dewatering sieve which combines
the characteristics found in cyclones, sieve bends,
vibrating screens and cross flow screens has achieved
significant results in several U.S. coal preparation plants
during the last several years. The new dewatering device
is called the Vor-Siv and is manufactured by the Perforated
Metal Divisions of the National Standards Company under
licensing agreement with the Polish Government. The Vor-,
Siv, shown in Figure 8-9, is a cross between a sieve bend
and a centrifuge; it has no moving parts, yet provides
highly efficient centrifugal dewatering action.
Separation of fine-grain solids through the use of the
Vor-Siv is accomplished by the spiraling or vortex flow of
230
-------
SCREEN
i -
W
COLLECTION BOX
FOR EFFLUENT
Source: National Standard Company
DISCHARGE OUTLET FOR
DEWATERED AND CLASSIFIED
MATERIAL
J.J.DAVIS
ASSOC I ATE S
VOR-SIV
Figure 8-9. DCN
-------
a slurry over a stationary inverted cone-shaped wire
screen. The feed is introduced into the Vor-Siv through a
directional nozzle onto a circulating raceway. A certain
minimum head is necessary to accelerate the feed slurry
against the walls of the raceway, causing partial stratifi-
cation of solids away from the associated water. As the
semi-stratified feed stream loses energy, it spills from
the raceway into a conical basket made of radially-slotted
profile wire. The remaining energy in the feed stream
creates a downward spiraling vortex flowing perpendicular
to the slotted openings in the upper three-fourths of the
basket. The solids flow down the screen to a discharge
outlet at the point of the vortex while the liquid with
the undersized particles flows through the fine slits of
the screen. The Vor-Siv is reportedly capable of perform-
ing several tasks such as classifying, desliming, scalping
and dewatering prior to the vibrating screen or centrifuge
process. However, to date, the most common use for the
Vor-Siv has been the dewatering of clean coal prior to
centrifuging.
Comparisons of generally accepted sieve bend and
cross flow screen applications and Vor-Siv applications
are of interest. Sieves and cross-flows with 28-mesh
sizing capability are generally assumed to have a capacity
of about 30 to 40 gpm per square foot of wire surface.
Some applications of sieve bends and cross-flows have been
as low as 20 gpm per square foot of screen area while most
Vor-Sivs are operating in the nominal range of 50 to 55
gpm per square foot. Feed rates on sieve bends of 30 to
40 gpm per minute and Vor-Sivs at 50 to 55 or even 70 gpm
can be expected to produce moisture in high 20 and low 30
percentile. A Vor-Siv at 70 gpm separating at 28-mesh
can reduce moisture to about 28%. Generally 34 to 38
232
-------
percent surface moisture can be expected from sieve bend
and cross-flow screen applications.
- 8.2.3 Centrifugal Dewatering
In a centrifuge, the coal and water are subjected to
a spinning action which usually increases in intensity as
the coal progresses through the machine. The spinning
action, or centrifugal force that is induced tears the
water away from the coal particles and produces a dewatered
coal.
Centrifugal force is widely used when a force greater
than that of gravity is desired for separation of solids
and fluids of different densities, i.e., coal and water.
A centrifugal force is created by moving a mass in a curved
path. The force is exerted in a direction away from the
center or curvature of the path. The centripetal force is
a force applied to the moving mass in the direction toward
the center of the curvature which causes the mass to travel
in a curved path. If these forces are equal, the particle
continues to rotate in the circular path around the center.
If these forces are not equal, the particle passes through
the screen and exits the device as fine size coal. Figure
8-10 graphically depicts the centrifugal force activity
within a horizontal centrifuge.
In addition to the centrifugal force, the initial
impact of the coal particles against the screen surface and
the subsequent impact of the coal against coal plays an
important part in the dewatering process within a centri-
fuge by breaking down the surface tensions between the coal
solids and the water.
The effectiveness of the dewatering action for any
particular machine is governed by the size consist of the
coal feed and the centrifugal force imparted to the water
233
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SLURRY FEED
CENTRIFUGAL FORCE
PERPENDICULAR TO
THE ROTATING AXIS
ROTATING DRUM
SCREEN
LIQUID AND
ULTRA-FINES
DEWATERED COAL SOLIQS
J.J.DAVIS
ASSOCIATES
CENTRIFUGAL
FORCE DIAGRAM
Figure 8-10 DCN
234
-------
on the coal. Fine coal has a larger surface area per unit
weight than coarse coal so its capacity for retaining
moisture is much greater: As the quantity of fines enter-
ing a centrifuge increases, the cake moisture increases.
As the percentage of fines in the slurry feed increases,
longer centrifuging time or increased centrifugal force is
required to maintain a cake or minimum moisture content.
Since the centrifugal force speeds up the separation
of the solids from the liquid, it would seem logical to
design machines for maximum centrifugal force. Pure
centrifugal force is not, however, the only consideration.
While centrifugal force helps solids settle, this same
force is the enemy of solid discharge. Discharging coal
particles becomes more difficult as the centrifugal force
increases. For example, at 3,000 gravities and one ton
per hour solids throughput, the discharge scroll of a
solid bowl centrifuge is in effect pushing 3,000 tons of
coal solids per hour up the drainage duct and consuming a
great deal of energy in the process. Additionally, when
centrifuges are operated in the higher force ranges,
tremendous pressures are set up between the solids and the
centrifuge bowl creating high frictional forces which
combine with the very abrasive characteristics of the coal
causing costly machine wear.
In general, three types of centrifuges are currently
being used in the U.S. to dewater fine bituminous coal.
These include the solid bowl or Bird, the perforated bas-
ket machines and the vibrating basket machines (both
horizontal and vertical axles). These major types are
discussed briefly in the paragraphs that follow:
Solid Bowl Centrifuges, shown in an example in
Figure 8-11. The two principal elements of the
solid bowl centrifuge are the contoured rotating
235
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cn
SOLIDS DISCHARGE
PORTS & PLOWS
WASH
AREA
WASH NOZZLE
SPLASH COMPARTMENT
FEED PORTS
POOL-LEVEL
ADJUSTABLE EFFLUE*>
SOLIDS DISCHARGE
EFFLUENT DISCHARGE
J.J.DAVIS
A 5 S OC I ATE S
j BIRD SOLID BOWL
! CENTRIFUGE
Figure 8-11 I DCN
-------
bowl which is the settling vessel and the convey-
or or scroll which discharges the settled solids.
The bowl has adjustable overflow weirs at its
larger end for the discharge of the effluent.
The solids are discharged at the opposite end
through fixed ports. As the bowl rotates, the
centrifugal force causes the slurry to form an
annular pool, the depth of which is determined by
the adjustment of the effluent weirs. The solids
discharge end of the bowl is reduced in diameter
so that it is not submerged in the pool and thus
forms a drainage deck for dewatering the solids
as they are conveyed across it by the scroll.
The principal advantage of the solid bowl centri-
fuge is that is can be used to dewater very
dilute fine slurries. However, this machine
requires considerable power because it must
accelerate the water load as well as the solids,
and because the scroll must push the solids up
to the discharge ports.
Perforated Centrifuges are shown in Figure 8-12
which depicts a perforated basket centrifuge with
a transport device, and Table 8-10 highlights
typical performance characteristics of perforate
basket centrifuges. These units have two
rotating conical drums. One drum turns inside
the other at a slightly slower speed. The outer
drum or basket is usually made of stainless steel
wire with replaceable screens mounted on its
inner surface. The inner drum or scraper carries
the blades which move the coal downward to the
discharge area. The wet coal enters the machine
Table 8-10
36 In. Diameter Positive Discharge Perforate
Basket Centrifuge Performance
Feed—65 tph, >a x 0"—20% to 35% surface moisture
% Recovery—90% depending upon friability of coal
% Product Moisture—6% surface moisture
Motor Requirements—50 hp, 180 rpm, normal starting torque
Operating Speed Range—550 rpm to 750 rpm
Approximate G Forces Developed—150 to 300
237
-------
: -
U3
0
i
••
.
FEED (SOLIDS AND LIQUIDS)
PERFORATED
SCREEN FOR
REMOVAL
OF LIQUID
END PRODUCT
(SOLIDS)
Source: Centrifugal and Mechanical Industries, Inc.
LIQUID
DRAINED
AWAY FOR
RE-USE OR
DISPOSAL
J.J.DAVIS
ASSOCIATES
MANAGEMENT ENGiNEERS
PERFORATE
BASKET
CENTRIFUGE
Figure 8-12. j DCN
-------
at the top where it falls on the apex of the cone
and the centrifugal force developed by the
rotating cone throws the coal-water mixture
against the screen. The water passes through the
perforations and is collected in an effluent
chamber. The coal is gradually worked to the
bottom by the scraper where it drops out by
gravity.
Vibrating Basket Centrifuges are displayed in
Figures 8-13 and 8-14 which depict perforated
basket vibrating centrifuges. Typical reference
data for these units are shown in Table 8-11.
These vibrating basket centrifuges, whether
horizontal or vertical, are the most common units
being installed in modern preparation plants.
Table 8-11
Typical Performance Data for Vertical
Vibrating Basket Centrifuges
Feed Range - 60 to 150 tph
Sizes Handled IV to 48 Mesh
Horsepower - 25 - 40 hp drive motor,
5 hp Vibration motor
% Recovery - 97% or higher depending upon friability
of coal
Operating Basket Speeds - 200 to 450 rpm
Approximate G forces developed - 25 to 120
Feed Size - V x 28 Mesh
These units differ from other perforated basket
machines in that the rotating basket is vibrated
in such a manner that the coal solids are
expelled from the machine without the use of a
transport device. The slurry feed passes down an
inlet chute where it is gently distributed onto
the inner surface of the screen basket. The
rotating screen basket is kept in axial vibratory
motion by a vibrating unit. The axial vibrations
move the coal solids towards the larger diameter
of the basket. In addition, the vibrating action
keeps the basket opening clear and constantly
loosens up the cake which improves the dewatering
239
-------
COAL WATER SLURRY
(FEED)
ROTATING PERFORATED DRUM
SCREEN FOR REMOVAL OF THE
LIQUID AND ULTRA-FINES
! -
-
HORIZONTAL
VIBRATING BASKET
CENTRIFUGE
LIQUIDS AND ULTRA FINES
DRAINED AWAY FOR RE-USE AND DISPOSAL
Source: McNally-Pittsburq
Figure 8-13. I DCN
-------
PERFORATED SCREEN
FOR REMOVAL OF LIQUID
FEED (SOLIDS AND LIQUIDS)
LIQUID
DRAINED AWAY
FOR RE-USE
OR DISPOSAL
END PRODUCT
(SOLIDS)
END PRODUCT
(SOLIDS)
Source: Centrifugal and Mechanical Industries, Inc.
J.J.DAVIS
ASSOCIATES
ANAliCMENf ENG
VERTICAL VIBRATING
BASKET CENTRIFUGE
Figure 8-14. [ DCN
-------
action of the centrifuge. The dewatered solids
which are thrown out at the large diameter end of
the screen basket fall freely down to the collec-
tion belt. The liquid which is centrifuged out
is ejected at the side. These machines are not
operated at as high a speed as those with
transport devices, therefore the product moisture
is usually higher. However, machine wear is low,
horsepower requirements are less and there is
little or no product degradation.
8.2.4 Filtration
Dewatering by filtration is coming to play a major
role in all wet cleaning plants. The recovery of clean
coal solids and refuse solids from the fine coal circuit
is the primary function of these filters. The filters
process a suspension with a high percentage of coal or
refuse solids and separate the water to produce a compact
wet cake with an approximate surface moisture of 18 to 40
percent, depending upon the size consist of the feed.
Coal and refuse slurries have been successfully
dewatered by both vacuum filters and pressure filters.
The most common filtering system found in the coal pre-
paration plants in this country is the vacuum filter. The
separation of the solids on a vacuum filter is accomplished
by placing a filter surface in the suspension and applying
a suction behind the filter to draw the water and solids to
the filter, thereby retaining the solids on the surface and
drawing the water through. The solids trapped on the fil-
ter (the cake) are slowly rotated approximately 120 degrees
out of the slurry mixture to permit the cake to dry. The
cake is then lifted off the filter surface before the
surface re-enters the suspension by increasing the air
pressure behind the filter to loosen the cake and then
removing the cake from the surface with scrapers.
There are two basic types of vacuum filters in use—
the disc filter and the drum filter. Figure 8-15 depicts
242
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a typcial disc-type filter and its associated activities.
Disc-type filters range in diameters up to 13*5 feet with
as many filter discs as necessary to provide a sufficient
amount of filtering surface. The discs operate in a trough
with some type of agitating device to help keep the solids
in suspension.
CAKE
\
PRYING ZONE
DISCHARGE ZONE
SLURRY FEED
DISCHARGE
HOPPER
SINGLE
SECTION
n V£&#tt-.
li»
OVERFLOW
INDIVIDUAL
TROUGH
Figure 8-15
Operational Diagram of a Coal Vacuum Filter
Figure 8-16 depicts the individual filter compart-
ments for a new disc-type filter and Figure 8-17 shows the
standard disc filter in a preparation plant. The disc-type
filter has several advantages over the drum-type filter:
the disc filters are lower in initial capital cost, require
243
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CAKE
CAKE
m
INDIVIDUAL
TROUGH
VALVE
_ HEAD
FILTRATE
— SLURRY
Figure 8-16
Individual Filter Compartments
Figure 8-17
Standard Vacuuui Filter Installation
244
-------
less floor space per filter capacity and maintenance costs
are less.
The operating principles of drum-type filters are
similar to the disc-type filter except the filter surface
is one long drum of varying lengths and diameters. Figure
8-18 shows a profile of the drum-type filter. The only
advantage to a drum-type filter over the disc-type is that
if a thin filter cake is being produced, the drum-type
will generally permit more complete removal of the filter
cake..
Although pressure filters have found wide acceptance
outside the United States, their extremely high initial
cost and lack of automation has made them unacceptable to
the American coal preparation industry. The pressure fil-
ter produces a relatively dry filter cake and a solid free
effluent (less than 1000 ppm solids). Table 8-12 compares
the relative differences between a pressure filter and a
disc filter producing 30 tons per hour solids from a 30%
solids feed.
Table 8-12
Pressure vs Disc Filter
Feed
Dry Tons Per Hour
Cake Moisture
Capital
Pressure Filter
30% Solids
30
20-23%
$2.4 million
Disc Filter
30% Solids
30
34-40%
$200,000
It is obvious that although the pressure filter
produces a much more desirable cake, the capital cost is
245
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.
-
Rotary Drum
Coal Filter
-------
appreciably higher than a disc filter. The operating
costs are also higher because of the semi-automatic,
cyclical nature of the filter which requires nearly constant
attendance by an operator.
The performance characteristics of any of the filters
discussed above are dependent upon a multitude of varia-
bles, the most important of these are listed and discussed
in the paragraphs that follow:
Filter feed solids concentration—is perhaps the
most important variable to be considered. A
general plot of the dry cake output vs feed
solids concentration is shown in Figure 8-19.
The coal slurry exhibits a sharp incremental
rate increase of filtration rates above 35 per-
cent solids. Above the approximately 58 percent
solids, the transport of coal slurry to the
filter is difficult. Controlling the solids
concentration between the limits of 45 to 55
percent by the use of thickening devices such as
cyclones and classifiers minimizes filter area
requirements and filter operating costs.
zoo
150
0.100
S
50
10 20 30 4O 50
Filter F««d Solids Conctntrolion - Wt %
60
Figure 8-19
Filtration Rate vs Feed Solids
247
-------
Size consists of solids in feed—for the usual
minus 28-mesh clean coal slurry, the general
filtration rate curve shown in Figure 8-19 holds
true. However, as particle size decreases, the
feed solids concentrations at which a sharp
increase in filtration rate occurs decreases,
and there is a decrease in the maximum obtainable
feed solids concentration. However, it has been
established that the minus 200-mesh portion of
the solids have the most significant impact upon
filtration rates. The minus 200-mesh solids
contain a very high percentage of clay or slimes
which reduces the permeability of the cake,
reduces the filtration rate and increases the
cake moisture.
Filter media—contributes to a great extent to
the filtration rate, cake moisture content and
filtrate clarity of the filtering operation. The
three most effective filter media in use in
modern preparation plants are stainless wire
mesh, saran and polyethylene. The filter charac-
teristics of each of these filter media are
similar. They all generally permit the minus
200-mesh particles to pass, have minimum blinding
characteristics and good cake release character-
istics. The primary differences between any one
medium and another relate to initial capital
cost and filter life. Stainless steel wire may
have an initial capital cost of $3.00 plus per
square foot of surface area and a filter life of
up to three years. On the other hand, saran and
polyethylene may have a filter life as short as
three months.
Cake air requirements—are primarily a function
of cycle time and coal particle size. However,
coal cakes of minus 28-mesh particles generally
require an air flow expressed as three cubic
feet of free air per minute per square foot of
area (3 cfm/ft2)-compressible. On minus 28-mesh
coal, at least 22-in. mercury vacuum must be
generated to obtain the minimum cake moistures
and the maximum cake rates—3 cfm/ft2, permits
a vacuum differential of at least 22-in. mercury.
Because coal cakes are essentially non-compressi-
ble, increasing the vacuum differential would
not be economical either in increased solids
recovery or decreased cake moisture control.
248
-------
Figure 8-20 is a schematic diagram of a fine size coal
filter installation and depicts the degree of complexity
of this portion of the fine size coal dewatering and drying
module. The complete description of the entire filtering
circuit is beyond the scope of the presentation; however,
when one considers the cost of operating a filter circuit
vs the recovery of between 50 and 100 tph of solids, it is
not difficult to comprehend the high cost of fine size coal
dewatering.
Figure 8-20
Schematic Diagram of a Typical Fine Coal Filter Circuit
8.2.5 Thermal Drying
As discussed in the other portions of Section 8.2,
surface moisture of the coarse coal product may be removed
by natural drainage and/or screening; however, for the
intermediate and fine size coal and refuse sizes, the
additional step of centrifugation or filtration is usually
required. When a surface moisture of intermediate and
fine sizes of coal is required which goes beyond the
limits of the mechanical devices discussed, the remaining
moisture must be removed by evaporation in some form of a
249
-------
heat dryer. Thermal coal dryers may be grouped into six
basic types. These are:
fluidized bed,
suspension or flash,
multi-louver,
vertical tray and cascade,
continuous carrier or screen and
drum or rotary type.
Coal industry trends in the application of the
preceding types of drying facilities have exhibited:
expanding general application of coal drying (from 32 to
57 million tons between 1958 and 1964) and expanding
specific application of fluidized bed coal drying (from 1
to 38% of all coal dryers between 1958 and 1964). However,
while in 1972 there were 184 preparation plants employing
thermal drying units, in 1973 that number had decreased
to 162. Likewise, the thermally dried tonnage of bituminous
coal and lignite fell from 53 million tons in 1972 to 46
million tons in 1973. Indications are that during 1974
less than 10% of the total production of bituminous coal
and lignite was thermally dried.
In 1973, the distribution of the six types of dryers
discussed was as follows:
fluidized bed (66),
multi-louver (16),
rotary (36),
screen (12),
suspension or flash (31) and
vertical tray and cascade (1),
for a total of 162 thermal drying units.
250
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All industrial coal dryers now in use are the continu-
ous direct contact type which employ convection as a major
means of heat transfer. Thus, hot gases and wet coal are
brought into intimate contact with each other on a continu-
ous gas flow—coal feed basis. The hot gases used for
thermal drying are usually the gaseous combustion effluent
from a coal burner. Sufficient excess air is fed to the
burner to generate an off gas of the optimum temperature
range for coal drying. This gas contains unburned oxygen
and nitrogen from the burner air feed and carbon dioxide
and water vapor as gaseous combustion products. A fan or
blower is used to force the hot gas up through the
fluidized bed-of drying coal. A knowledge of the behavior
of the fluidized coal bed and of the drying properties of
the combustion of gas over a range of temperatures is
necessary for an understanding of thermal coal drying and.
is beyond the scope of this publication. A typical coal
dryer is shown in Figure 8-21.
A multitude of factors affect the performance
capability of a thermal coal dryer: drying temperature,
heat, fuel, inlet temperature, air volume and dryer size.
However, the greatest single factor affecting performance
is temperature. Temperature in the drying zone should
always be as high as safety will permit. When low
temperatures are used, sensible heat losses in the
exhaust gas are usually greatly increased because a high
air flow is needed to deliver the required heat. Moreover,
lower temperature means low thermal efficiency, higher
fuel and power requirements and increased amounts of dust
carryout. Coal drying temperatures vary according to the
type of dryer, coal and drying conditions. For example,
a cloud of minus 200-mesh coal dust containing 32% volatile
matter will ignite at approximately 1,100 degrees
251
-------
The No. 10 Flowdryer includes exceptional features and reveals extensive flexibility of Flowdryer to meet
practically any production requirement or air control standards. Among special features of this unit capabl
of handling 594 tph at 11.6 percent moisture, feed size range of 6 mesh to 0 and achieve 53 tph evaporation
rate are: • an unusually high pressure drop through drying bed, resulting in high velocity drying gases
breaking up and effectively drying filter cake balls; • an oversize furnace with the added volume providing
better mixing of drying gas witfi product, uniform temperature and pressure under drying bed, and longer
furnace life; • a band of high alumina refractories at burner level and super duty refractories in remainder
of the furnace walls for minimal wall erosion; • judicious use of stainless steel for free flow of materials;
and • special high energy scrubbers to meet air pollution control standards. Scrubbers employ stack
testing extensions for sampling emission.
Source:
Figure 8-21
Typical Thermal Coal Dryer
McNally-Pittsburg'Manufacturing Corp.
252
-------
Fahrenheit, while a layer of such dust will ignite at
about 350 degrees Fahrenheit. The ignition temperatures
discussed are above normal coal dryer discharge tempera-
tures and do not take into account the spontaneous heating
of coal which is influenced by particle size, volatility,
mineral matter, moisture and temperature. For example.
bituminous coal which is heated to only 140 to 150 degrees
Fahrenheit can catch on fire..from spontaneous combustion
within hours after being loaded into railroad cars.
There has been much written on the design theory and
operational characteristics of each of the various types
of thermal coal driers—a detailed discussion of the
inner workings of these units is beyond the scope of this
work. However, the following discussion will outline the
functioning of fluidized bed dryers. Basically, the
principle of fluid bed drying is uncomplicated: Air
heated by either a pulverized or stoker-fired coal furnace
is pulled upward through a constriction plate by a
negative pressure suction fan. The heated air passing
through the orifices of the constriction plate creates
extremely high velocity air currents which suspend the
coal above the plate in a buoyant effect and cause the
mass to act like a turbulent liquid. This "liquid"
flows at a relatively even depth from the feed end to the
discharge end of the dryer. In order to overcome the
relatively high pressure drop, most dryers employ two
fans. The intake fan pressurizes the furnace providing
enough pressure to overcome the resistance to and through
the restriction plate. An exhaust fan beyond the primary
dust collector creates a suction, pulling the hot gases
on through the collecting system and out the exhaust
stack. It is assumed that all the drying gases pass
through the dust collector, thereby preventing the loss
253
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of fines through leakage. The coarse dried material
discharges from the dryer through a motorized conveyor-
airlock. The fines which are suspended in the air stream
are collected and usually recombined with the coarse
material at the discharge.
The principle of fluidization as applied to the
drying process has resulted in a thermally efficient method
of moisture removal from the coal solids. The fluidized
coal solids are completely surrounded by hot drying gases
and intimate contact is obtained between the air and the
coal. For every material there is a certain gas flow rate
which will suspend the material so that its particles
become disengaged and can be moved with a small amount of
energy. While drying can be obtained in any phase of
fluidization, the optimum condition is in the mild or
incipient phase of fluidization. Operation at this point
reduces dust loading, yet provides sufficient agitation to
give good air to surface contact.
Air volume is controlled by sensing the amperes of
the induced draft fan motor, and a balance is maintained
by opening and closing the induced draft fan damper. The
temperature is controlled by sensing the exhaust gas
temperature of the dryer and controlling the burning rate
of either the stoker or the pulverizer. The exhaust
t
temperature is the prime controlling point; however,
should the inlet temperature exceed the present high limit,
the control will then switch the inlet temperature control-
ler automatically and turn the air furnace to a low fire.
Should either the furnace or dryer exhaust gas tempera-
tures exceed a pre-set high limit, the drying system will
fail and the following sequence of events will occur: a
visual signal lamp will light up, a warning horn will
sound, the furnace by-pass stack damper will open to
254
-------
by-pass the hot furnace gases to the stack and, to provide
further insurance, a protection damper located between the
air furnace and the dryer will close and isolate the dryer
from the furnace completely—simultaneously a cooling
damper will open to cool down the dryer. A central static
pressure gauge is located in the control panel in the
control room to indicate whether any plug-ups occur at
various points throughout the system.
The feed rate of the dryer is controlled by a surge
bin and variable speed screw feeders. As the rate of surge
varies, level indicators located within the bin sense the
level and increase or decrease the speed of the screw
feeders to maintain balance within the dryer. Most dryers
are designed to automtically handle load fluctuations and
start and stop operations as encountered in normal prepara-
tion plant operations or in emergency shutdowns with a
minimum of operator attention and maximum safety. Figure
8-22 shows a typical thermal dryer installation and
Figure 8-23 highlights potential air pollution problems.
8.3 THICKENING COAL AND REFUSE SLURRIES
As indicated in Section 8.2, Methodologies of Dewater-
ing and Drying the coal and refuse solids, there is usually
considerable underflow from the screening or centrifuging
processes. This underflow contains a percentage of coal
or refuse solids that must be recovered. In addition,
specific elements of the intermediate and fine size coal
cleaning circuits discussed in Chapter 7 create very
dilute slurries of coal or refuse products. In each
instance, these dilute slurries must be thickened before
they can effectively be further processed by filtration or
if coarse enough by centrifugation. Of the devices used
to thicken these slurries in the modern preparation plant,
two merit discussion: hydraulic cyclones and classifiers.
255
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Figure 8-22
The Thermal Dryer
Figure 8-23
Obvious Air Pollution
Problems When Unchecked
256
-------
8.3.1 Hydraulic Cyclones
In addition to the centrifuges discussed in Section
8.2.3, the cyclone thickener uses the principles of centri-
fugal force to thicken or classify coal or refuse solids
and thereby aid in product dewatering. Cyclone thickeners
are essentially hydraulic centrifuges: They are either
used as a secondary dewatering circuit for intermediate
coal sizes or as a primary circuit in dewatering fine size
coal solids.
A cut-away view of a hydraulic cyclone is shown in
Figure 8-24. The cyclone body generally consists of a
short cylindrical section attached to an inverted truncated
conical section. The apex of the conical section is
referred to as the underflow orifice. A central overflow
orifice or vortex finder is fitted to the base of the cone.
Although the complex inner workings of the cyclone are not
fully understood, there is a basic understanding of how the
unit functions. The coal and water mixture enters the
upper part of the cyclone tangentially at a high velocity
through an orifice into the cylindrical section, thereby
creating a centrifugal force field. The heavier particles
move to the outside wall arid slide downward to the apex
of the cone and out the underflow orifice in a thickened
slurry. The lighter particles, having less tendency to
settle at the wall, are forced to the overflow by the
upward velocities at the core of the cyclone. Figure
8-25 depicts the flow patterns within a cyclone.
The cyclone underflow sprays into a collecting trough
and flows by gravity to the secondary dewatering process.
.The overflow, which may or may not need further process-
ing, is controlled by an overflow valve as well as by the
size of the underflow and overflow orifices. Normally
the underflow volume is about 10 percent of the feed
257
-------
258
J.J.DAVIS
ASSOC I ATES
HYDRAULIC CYCLONE
Figure 8-24 I DCN
258
-------
volume. By closing down the overflow valve, back pressure
is applied which forces more material out the underflow;
the result is lower underflow concentrations and higher
recovery of fine solids.
The performance characteristics of cyclone thickeners
vary greatly with the actual and relative diameters of the
upper and lower outlet valves as well as with the diameter
of the inlet orifice. All hydraulic cyclones incorporate
easy adjustment of these dimensions. The nature of the
spigot discharge varies according to operating conditions.
Under normal conditions the discharge is a peripheral
whorl breaking into a spray as it leaves the spigot or
nozzle. Subsequently, air enters the center of the whorl
and discharges through the center of the similar whorl at
the top of the overflow pipe. This air column is generally
accepted as being continuous from bottom to top forming
the core of,the vortex. When the overflow tube projects
to the level of the junction between the cylindrical and
conical section, solids recovery is maximized.
Extensive experimentation has shown that although
throughput with a given feed orifice increases with the
increase in feedline pressure, solids recovery at the
underflow does not increase. This is taken to be because
the decreased time of residence within the cyclone counter-
balances the increase in settlement rate resulting from
the velocity increase. However, if the pressure increase
is accompanied by a reduction in the nozzle area so as to
keep resident time constant, solids recovery is increased.
A decrease in the spigot diameter with no other changes
increases pulp density in the underflow. If this reduction
in diameter is carried too far, the air core is lost and
solids elimination decreases sharply. A decrease in the
259
-------
diameter of the overflow pipe decreases the solids content
of both overflow and nozzle products. Solids in overflow
increase with the solids content of feed.
Cyclone thickeners are available in many sizes. The
size chosen for a particular installation is directly
dependent upon the size consist of the feed. For example,
three inch diameter cyclones are used to process fine
slurries containing particles generally having 8-mesh by
0 size range. The units are normally arranged in banks
containing 22 cones each, with a common manifold in the
one feed line and one overflow line. One bank of the
cyclones will handle a flow of approximately 250 gpm of
slurry at a feed pressure of 40 psi. The top size of
feed to an 8 inch diameter cyclone should be less than
3/16 inch. The standard 8 inch diameter cyclone will
process approximately 110 gpm of slurry at a feed pressure
of 40 psi. The 8 inch diameter cyclones are normally
arranged in banks of two, three or four cones with common
feed and overflow manifolds.
The 14 inch diameter cyclone has a capacity of 325
gpm at a feed pressure of 40 psi and is designed to handle
slurries with particles up to 1/4 inch. They may be
operated as a single unit or connected in parallel to make
up banks. Figure 8-25 displays a bank of 4 cyclones in an
actual preparation plant. Typical performance data on a
14 inch diameter cyclone is shown in Table 8-13.
8.3.2 Classifiers
Classifiers are frequently used in coal preparation
plants to assist in the dewatering of coal and refuse
solids. However, their most typical operation is the pre-
thickening of the refuse solids suspended in the plant water
circuit prior to the thickening or filtering operations.
260
-------
Table 8-13
Typical Performance of a 14-inch Diameter
Hydraulic Cyclone
Application: Thickening of 28 mesh
Feed Pressure: 25 psig Flow:
Size , Microns and Tyler Mc.tli
0- 20 Microns
20- 44 Microns
325-200 Mesh
200-100 Mesh
+ 100 Mesh
Concentration by Weight
Recovery
• Remarks: Above results show typic
sludge screen or vacuum 1
by 0 fine
300 gpm
l-'ecil
27.0%
12.0%
9.0%
15.0%
37.0%
100.0%
10.0%
al 14- in.
liter.
coal slurry.
per cyclone.
Underflow
3.7%
3.0%
5.0%
19.6%
68.7%
100.0%
46.0%
53.5%
cyclone performance
Overflow
53.8%
22.4%
13.5%
9.7%
0.6%
100.0%
5.0%
thickening feed to
This function is primarily a sizing operation of the
solids in suspension. These sizing classifiers do not
require additional water besides that present in the slurry
being treated. They utilize free-settling conditions to
effect sizing as much as possible and are unaffected by
the specific gravity and shape of the particles. The size
at which a separation is made ranges from 20- to 300-mesh.
Sizing classifiers are operated at the dilutions ranging
from a solid content of 3 to 5 percent by weight if sizing
is at the extreme fine end or up to 30 or 35 percent by
weight if sizing is at the coarse end.
There are a variety of classifiers in use, but they
may be grouped into two main types on the basis of the
flow of the slurry: horizontal-current and vertical cur-
rent. The most common type of classifier in use in coal
cleaning plants is the horizontal-current mechanical type
classifier. These types of classifiers generally have
mechanical devices to agitate the slurry and to carry the
settled solids away and are typified by the spiral or
screw classifier, shown in Figure 8-26.
261
-------
Figure 8-25
Typical Hydraulic Cyclone Installation
Figure 8-26
A Working Screw Classifier
262
-------
. Screw clasifiers consist of an inclined, round-
bottom tank with one or two spirals mounted on a through-
shaft parallel to the tank bottom. The spiral structure
effects the necessary agitation in the pool and conveys
the settled solids up the bottom of the tank to the .
discharge lip. The slurry is fed into the classifier with
a minimum head and at pool level to minimize undesirable
agitation. The pool level is maintained by adjusting the
height of the overflow weirs. The overflow drops into a
collection pipe and is usually routed to a thickener. The
underflow may report directly to the refuse belt if
sufficiently dewatered or to a secondary dewatering device.
The amount of water overflowing the weir determines the
size of the separation since the water overflowing the
weir varies with the velocity and vice versa. Additionally,
the speed of the spirals may have an effect on the size of
separation. Speeding up the spirals pulls more material
into suspension and increases the agitation thereby
effecting a separation at a coarser level.
263
-------
REFERENCES AND/OR ADDITIONAL READING
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264
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
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265
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
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Filtration: A Pilot Plant Study", U.S. Department of Interior,
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Coals by Stage Crushing", U.S. Bureau of Mines Report of Investi-
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U.S. Bureau of Mines Report of Investigations #7982, 1974
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Dorr-Oliver, Inc., "Merco Centrifugal Separators", Stamford, Connecti-
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October 1974
Enviro-Clear Co., Inc., "Coal Preparation Plant Clarifier-Thickener",
Bulletin C/ll/72, New York City
266
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Environmental Protection Agency, "Air Pollution Technical Publications
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Fair, Geyer, and Okun, "Water and Waste Water Engineering", Vol. 2,
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Fomenko, T.G.; Kondratenko, A.F.; Perlifonov, A.G., "Thickening of
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1973
Foreman, William El; Lucas, J. Richard, "Current Status of Hydro-
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Continuous-Cell Flotation of Coal: A Lab Study", U.S. Bureau of
Mines Report of Investigations #5989
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Tailing by the Admixture of Crushed Washery Refuse", U.S. Bureau of
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Warwick Plant", Coal Age, November 1974
Gospodarka, Gornictwa, "Possibilities of Mechanical Preparation Under-
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American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May.1975
Grimm, Bobby M., "Preparation Plant Corrosion Cost", American Mining
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Gvozdek, G.; Macura, L., "Hydraulic Mining in Some Deep Pits in
Czechoslovakia", Translated by National Coal Board (A 1683), Uhli
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267
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Hand, John W., "Drying of Western Coal", Mining Congress Journal
May 1976
Haskins, J. William, "The Economical Advantages of Drying Coal Fines
Using Indirect Heat Exchanging", NCA/BCR Coal Conference and Expo
II, October 1975
Henderson, G.S.; Andren, A.W.; Harris, W.F.; Reichle, D.E.; Shugart,
H.H.; Van Hook, R.I., "Environmental Assessment of SO and Trace
Element Emissions from Coal Utilization", Coal Utilization Symposium-
Focus on SO Emission Control, Louisville, Kentucky, October. 1974
Hewitt-Robins, "The Eliptex Dewaterizer", Engineering Bulletin No.
2103.0601X
Hill, Ronald D., "Water Pollution From Coal Mines", Water Pollution
Control Association of Pennsylvania, 45th Annual Conference, 1973
Hudy, J., Jr., "Performance Characteristics of Coal-Washing Equipment",
U.S. Bureau of Mines Report of Investigations #7154, July 1968
Hulett, L.D.; Carter, J.A.; Cook, K.D.; Emery, J.F.; Klein, D.H.;
Lyon, W.S.; Nyssen, G.A.; Fulkerson, W.; Bolton, N.E., "Trace
Element Measurements at the Coal-Fired Allen Steam Plant—Particle
Characterization", Coal Utilization Symposium-Focus on S0« Emission
Control, Louisville, Kentucky 1974
Humboldt-Wedag, "Manufacturers Brochures", Cologne, Germany
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Provence Coalfield", France, Australian Coal Conference
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Jacobsen, P.S.; Kokaski, M.; Geer, M.R., "Performance of a Screw-
Type, Classifier Cyclone Combination", U.S. Bureau of Mines Report
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Jeffrey Mining Machine Co., "Jeffrey Mining Machine Company: Manu-
facturers Information", Columbus, Ohio
Jenkinson, D.C., "Some New Coal Preparation Developments in the United
Kingdom", National Coal Board Bulletin M4-B148
268
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Johnson Divison, UOP Company, "Brochure - 1975"
Jonakin, J., "Solving the SO Problem—Where We Stand with Application
and Costs", Coal Age, May 1975
Kalb, G. William, "The Attainment of Particulate Emission Standards
at Fluidized-Bed Thermal Coal Dryers", American Mining Congress
Coal Show Detroit, Michigan, May 1976
Kent, James A. (Editor), "Riegel's Handbook of Industrial Chemistry
(7th Ed.)", Van Nostrand Reinhild Publishing Company, New York, 1974
Kester, W.M., "Magnetic Demineralization of Pulverized Coal"
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
Kodentsov, A.A.; Kurkin, V.F.; Krasnoyarskiy, L.S.; Papkov, M.N.,
"Dewatering of Coal and Rock, Clarification of Waste Water During
Driving by Hydromechanization", Ugol Ukrainy #11 (Translated by
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Kollbdiy, K.K.; Borodulin, V.A.; Nazarov, P.G., "Processing of Coal
Mined by the Hydraulic Method", Ugol #9, 1974 (translated by
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Korol, Dionizy, "Influence of Hydraulic Getting on Mechanical Coal
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Lamella (Sala of Sweden), "Theory and Design of the Lamella Gravity
Settler", Technical Bulletin #105, May 1975
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
LLewellyn, Robert L., "Coal Preparation", Elements of Practical Coal
Mining, Seeley W. Mudd Series, American Institute of Mining,
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Lotz, Charles W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Lowman, Stephen G., "Westmoreland Coal's Bullitt Plant Upgrades Steam
Coal Quality", Coal Age, 1973
Lowry, H.H. (Editor), "Chemistry of Coal Utilization", John Wiley &
Sons, Inc., New York, New York, 1963
269
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Lovell, Harold L., "Sulfur Reduction Technologies in Coals by Mechani-
cal Beneficiation (3d Draft)", Commerce Technical Advisory Board
Panel on SO Control Technologies, March 1975
Manwaring, L.G., "Coarse Coal Cleaning at Monterey No. 1 Preparation
Plant", Mining Congress Journal, March 1972
Markley, R.W.; Cavallaro, J.A., "Efficiency in Cleaning Fine Coal by
Froth Flotation—A Cell by Cell Pilot Plant Evaluation", Mining
Congress Journal, June 1974
Mathur, S.P., "Hydraulic Mining of Coal", Journal of Mines, Metals and
Fuels, May 1972
McNally-Pittsburg Manufacturing Corporation, "Coal Cleaning Plant
Prototype Plant Design Drawings", Department of Health, Education and
Welfare Contract 22-68-59
McNally-Pittsburg Manufacturing Corporation, "Coal Preparation
Manual #572", Extensive Analysis on McNally Pittsburg Coal Cleaning
Technology
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Cyclones", Coal Mining and Processing, May 1976
Metcalf & Eddy Inc., "Waste Water Engineering, Collection-Treatment-
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Miller, F.; Wilson, E.B., "Coal Dewatering - Some Technical and
Economic Considerations", American Mining Congress Coal Convention,
May 5-8, 1974
Morris, George J., "Reclaiming Coal from Refuse Ponds", American Mining
Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Moss, E.A.; kens, D.J., Jr., "Dewatering of Mine Drainage Sludge",
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National Coal Association, "First Symposium on Mine & Preparation Plant
Refuse Disposal", Coal and the Environment Technical Conference,
October 1974
National Coal Board, "Exploratory Trails in Hydraulic Mining at
Trelewis Drift Mine", September 1961
270'
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
National Coal Board, "Hydraulic Transport of Coal at Woodend Colliery",
September 1961
Nirtsiyev, "Hydraulic Extraction of Coal in the Donetz Basin Izdatel
'Stvo "NEDRA", Moscow 1969 (Translated by Terraspace)
Nunenkamp, David C., "Survey of Coal Preparation Techniques for
Hydraulically Mined Coal", Published for Terraspace Inc., July 1976
Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
Desulfurization", Chicago, Illinois, October 1965
Pritchard, David T., "Closed Circuit Preparation Plants and Silt Ponds",
Mining Congress Journal, November 1974
Protsenko, I.A., "The Technology of Beneficiation and Dewatering of
Coal Mined by the Hydraulic Method", Questions Regarding the Hydraulic
Production of Coal, Trudy VNIIGidrougol, Vol. XI, 1967 (Translated
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type Coal Cleaning Plant", August 1969
Roberts & Schaefer Company, "Material Handling and Processing Facilities
for the Mining Industry", 1974
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Cleaning Plant", January 1973
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Hydromechanization of Steep Seams in the Kuzbass", UGOL #7, 1973
Sands, P.F.; Sokaski, M; Geer, M.R., "Performance of the Hydrocyclone
As a Fine Coal Cleaner", U.S. Bureau of Mines Report of Investigations
#7067, January 1968
271
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Sarkar, G.G.; Konar, B.B.; Sakha, S.; Sinha, A.K., "Demineralization
of Coal by Oil-Agglomeration", Part I: Studies on the Applicability
of the Oil-Agglomeration Technique to Various Coal Benefication
Problems, India, Australian Coal Conference
Schuhmann, Reinhardt, Jr., "Metallurgical Engineering, Vol. I,
Engineering Principle", Addison-Westey Publishing Company, Inc.,
Reading, Massachusetts, 1952, p. 84 • - •
Skinderowicz, F., "Typical Technical Solutions of a Loading Point
During Gravity Hydraulic Transportation of Coal", Waidomosci
Gornicza, Vol. 10 #3, .1959
Sokaski, M; Sands, P.F.; Geer, M.R., "Use of a Sieve Bend and a
Scalping Deck With a Vibrating Screen in Dewatering and Draining
Dense Medium From Fine Coal", U.S. Bureau of Mines Report of
Investigations #6311
Stefanko, Robert; Ramani, R.V.; Chopra, Ish Kumar, "The Influence of
Mining Techniques on Size Consist and Washability Characteristics
of Coal", National Technical Information Service, Springfield,
Virginia, August 1973
Stoev, St.; Krasteva, K., "Coal Preparation by Reverse Stratification",
Bulgaria, Australian Coal Conference
Terchick, A.A.; King, D.T.; Anderson, J.C., "Application and Utili-
zation of the Enviro-Clear Thickener in a U.S. Steel Coal Preparation
Plant", Transactions of the SME, Volume 258, June 1975
Terry Richard L., "Minerals Concentration by Wet Tabling", Minerals
Processing, July/August 1974
Tieman, John W., "Chemistry of Coal", Elements of Practical Coal Mining,
Seeley W. Mudd Series, American Institute of Mining, Metallurgical
and Petroleum Engineering, Inc., New York 1968
Tyler, C.E., "Testing Sieves & Their Uses", Combustion Engineering, Inc.
Handbook #53, 1973 Edition
U.S.S.R., "Intensification of Coal Slurries Treatment and Dewatering
Processes", Australian Coal Conferences
Verschuur, E.; Davis, G.R., "The Shell Pelletizing Separator: Key to
a Novel Process for Dewatering and De-Ashing Slurries of Coal Fines",
Holland, Australian Coal Conference
272
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Warnke, W.E., "Latest Progress in Sulfur, Moisture and Ash Reduction '
Coal Preparation Technology", American Mining Congress Coal
Convention, Detroit, Michigan, May 1976
Wei-Tseng Peng, "The Jet-Cyclo Flotation Cell", The People's Republic
of China, Australian Coal Conference
Wemco Division, "Manufacturer's Catalog", Envirotech Corporation,
Sacramento, California, 1974
Yencey, J.F.: Geer, M.R., "Behavior of Clays Associated with Low-Rank
Coals in Coal-Cleaning Processes", U.S. Bureau of Mines Report of
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Yancey, J.F., "Determination of Shapes of Particles in Coal and Their
Influence on Treatment of Coal by Tables", AIME Translation, 94
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A New Dehydrator", Japan, Australian Coal Conference
273
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THIS PAGE INTENTIONALLY LEFT BLANK
274
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9. CLEAN COAL STORAGE AND HANDLING
9.1 OVERVIEW
The larger handling and producing systems in use
today are dependent on an assured supply of coal of
specific quantities being available at a specific time.
It is no longer feasible to load clean coal at the rate
of production of the coal cleaning plant. Since the
inception of the unit train, clean coal storage, in some
form, has become an economic necessity. Several of the
more important reasons for storing of clean coal are:
to quickly and economically load unit trains,
barges and other intermittent bulk transport
conveyances,
to facilitate the attainment of maximum product
uniformity of shipped clean coal,
to keep clean coal on hand for domestic and
truck trades and
to eliminate the dependency on preparation plant
production.
The relationship of the clean coal storage module to the
preparation plant is highlighted in Figure 9-1.
The reasons for clean coal storage are clear. There
are, however, numerous adverse factors to be considered.
Among them are:
the oxidation and spontaneous combustion of the
coal,
275
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1.
PLANT FEED
PREPARATION
2.
RAW COAL
SIZING
3.
RAW COAL
SEPARATION
4.
PRODUCT
DEWATERING WATER
FINE SIZE PRODUCT
5.
PRODUCT STORAGE
AND SHIPPING
J.J.DAVIS
ASSOC I ATES
'^Ar^A,,l ML'Jt E.NGINEEMS
Preparation Plant
Modules
Figure 4-2 I DCN
276
-------
the alteration of the physical properties of coal
while being stored,
the loss of product due to wind and erosion, and
degradation due to rehandling and
the increased capital cost of handling and stor-
age facilities.
The affinity of a coal stockpile to spontaneously heat
is very difficult to assess. It is, of course, directly
dependent on the amount of oxidation which takes place, but
oxidation, in turn, is dependent on many other factors
such as the rank of the coal (the higher the rank, the less
tendency to oxidize), the size consist of the coal in the
pile, the method by which it is stacked, the temperature
at which the coal is piled, external heat additions, the
amount and size of pyrite present, moisture content,
ventilation conditions in the pile, storage time and the
presence of foreign materials. Because each of these
variables is important, the spontaneous combustion of a
coal stockpile may take place under a certain set of
environmental conditions at one location, while not taking
place at another site with slightly altered conditions or
different coal characteristics.
Coal weathers as it oxidizes in storage. Weathering
or "slacking" as it is sometimes referred to, occurs more
readily in low-rank coals than high-rank coals. It is
defined as the disintegration of the coal on exposure to
the weather, particularly when alternately wetted and dried
or subjected to hot sunshine. This phenomenon is detri-
mental from the utilization standpoint, both in decreases
of heating value and loss of coking properties of the coal.
This factor has substantial bearing on the selection of
storage facilities at the plant, i.e., whether they should
be open or closed, although it has been found that the
277
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oxidation rate decreases with time and generally the loss
in heating value is not as great as once it was thought
to be.
Another consideration as to storage type is the
potential loss of coal product through windage (dust loss)
and erosion. This consideration is dependent on the
geographical location of the proposed storage site and may
be of significant importance.
The impact of any of the above factors may be greatly
reduced by using closed storage facilities such as bins or
silos. Closed storage systems are high capital cost items
and their use is restricted by economics. However, the
time of storage factor is of great importance in determin-
ing the type of storage. It has been found that short-term
storage, if done properly, can usually be of the open type
while a great deal more consideration must be given to
coal which is to be stored for longer periods of time. The
optimum storage of clean coal lies not only in the selec-
tion of the adequate type, but also in the proper construc-
tion and maintenance of the storage facility.
9.2 CLEAN COAL STORAGE
The reasons for storing clean coal have been presented
previously; and the methodologies of clean coal storage
will now be discussed. As a minimum, Jj hour of rated
plant capacity of clean coal is suggested as the minimum
storage necessary to provide a reserve against production
interruptions which would directly impact efficient
transport of the clean coal. It is, however, more common
to store larger quantities of clean coal either in bins
or silos or in ground storage facilities. Bins and silos
may be singular, monolithic storage areas ranging in
capacity from 1,000 tons to 15,000 tons per unit. It is
278
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common to find multiple clusters of bins or silos at a
storage facility. The cluster storage approach provides
flexibility, better reliability and the advantage of being
able to blend the final product mix. Ground storage capa-
city, on the other hand, ranges from a low of about 5,000
tons to a high of 30,000 tons and oftentimes more. Storage
facilities appear in a number of shapes with a multitude
of contributing variables. The use of large singular silos
is becoming more and more popular with increased unit train
loading, and as more economical methods of constructing
the concrete silos are developed, space-saving considera-
tions have also added impetus to the trend toward this
type of storage.
The industry trend is toward increased use of the unit
train concept for removing clean coal from the storage
area. Therefore, plant installations must have storage
facilities amenable to this system. The criteria used in
the decision as to which type of storage will be used at
a particular site include such factors as:
Whether or not the coal has been thermally dried.
There is a natural reluctance to put the coal in
open storage if it has been thermally dried. If
the market calls for a low moisture coal, a
closed storage bin or silo is desirable.
Is dust control critical? If so, a closed bin
or silo is desirable. If dust control is desir-
able but not critical, a standpipe or telescoping
tube in an open stockpile is adequate.
Is the weather such that coal would tend to
freeze in open storage or in rail cars? A
closed bin or silo is often better.
What initial capital is available for investment
in storage facilities?
279
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9.2.1 Open Storage for Clean Coal
Open storage, often called ground storage, is the
least expensive of all storage methods. It simply consists
of storing the clean coal directly on the ground or in
shallow pits in any of several configurations dependent on
the handling system being used.
The most common of the open storage configurations is
the conical-shaped pile. As displayed in Figure 9-2,
this configuration is used in over 60% of coal operations
employing unit train loading. A conical storage pile may
have a flat bottom using either coal in the dead storage
area or earth filled into a doughnut shape to serve as the
dead area. The majority of operators employing conical
pile storage use dead coal as a satisfactory enclosure.
The dead coal also constitutes a reserve for the loader.
Instead of coal, fabricated enclosures may occasionally be
employed. Earth embankments are used in a number of
installations. These embankments may completely enclose
the storage pile, or if terrain permits, may be left open
at strategic points for bulldozing or other methods of
moving to create additional storage. The slope of the
enclosure wall is usually 40 to 45 degrees or approximately
the angle of repose of the coal being handled. Addition-
ally, the storage area may be cut into hillsides using the
natural rock as a partial enclosure.
Concial stockpiles may have varying capacities
depending on the height of the pile and the angle of
repose of the coal. The major disadvantage of this type
of storage is the relatively low ratio of live to dead
storage. Assuming a 45° angle of repose, only about 1/5
of the coal in a conical pile is live coal if the only
recovery opening is in the center of the pile. To avoid
this, several openings may be used extending across the
280
-------
00
Telescopic
Chute
ELEVATION
Telescopic
Chute
Storage
^ft~ ( ' <*JVV~< •
7 -AA A A A A A ^
X A^J ^.
Collecting
Conveyor
-Feeder
SECTION
Ventilation
Pipe
*•
J.J.DAVIS
ASSOCIATES
Conical Shaped
Stockpile
Ficuro 9-2
-------
diameter of the pile. This may increase the live coal
ratio to about 55%.
Buildup of the conical pile usually begins on a pre-
pared, compacted surface. A fixed, cantilevered, stacker
conveyor delivers coal to the pile and is usually equipped
with a telescopic chute or fixed standpipe with multi-level
openings to restrict dust. The pile is situated over the
reclaiming tunnel and necessary feeders which feed onto a
reclaiming conveyor which, in turn, may deliver the product
to a loadout hopper over the track or tracks for unit train
loading.
Another open storage method consists of a long wedge-
shaped pile which is capable of storing from 40,000 to
100,000 tons of clean coal. These wedge-shaped piles are
built with a traveling stacker that operates with a belt
conveyor running parallel to the pile. The conveyor is
generally elevated to about half the height of the pile,
either on an earth fill or on a steel structure. The pile
is built as the movable tripper slowly traverses the length
of the pile. The stacker may have either a fixed or a
hinged boom, the latter serving to practically eliminate
dust problems.
Wedge-shaped piles can either be reclaimed by using
an under-the-pile conveyor system similar to that previous-
ly described for a conical pile, or a stacker/reclaimer
system may be employed for both functions. Both systems
are shown in Figure 9-3. The stacker/reclaimer system is
a more recent innovation, adapted from.strip mining
technology and initially used at power plants, but now
appearing at preparation plants as well. It is quite a
versatile storage method which allows storage on both
sides of the conveyor track.
282
-------
Stacker-Reclaimer
Underground Conveyor Reclaim System
: -
00
Source: McNally-Pittsburg
60 "Grots Conveyor « 45" Long
| S.CT.O
J.J.DAVIS
AS SO C I ATE S
Wedge-shaped
Stockpile
Fiquro
-------
A final type of open storage, frequently found at
power plants and finding increased application in prepara-
tion plants is the kidney-shaped stockpile shown in Figure
9-4.
FeoJtti-
SECTION THRU PILE
PLAN SHOWING FEEDER ARRANGEMENT
Figure 9-4
Kidney-Shaped Stockpile
Source: Coal Preparation, op.cit., p. 15-18
The kidney-shaped stockpile is formed by a stationary
radial stacker with a boom that rotates through an arc and
which raises and lowers as necessary. The stacker may be
either ground or tower mounted. This type of storage has
the major advantage of being able to stock a large supply
of clean coal using a minimum of space and handling. Off-
setting this advantage, however, are the disadvantages of
high capital investment, high maintenance costs and the
need for a more complex reclaiming arrangement to achieve
maximum efficiency.
284
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9.2.2 Closed Storage for Clean Coal
For various reasons, such as to prevent freezing, it
may be desirable to use enclosed storage facilities. When
such a situation exists, bins or silos are generally used.
These storage vessels are predominantly circular in shape
and may be made of either steel or concrete. An example of
a facility employing a combination of both the steel and
concrete type silos is shown in Figure 9-5.
Figure 9-5
Steel and Concrete Storage Silos
Source: FMC Mining Equipment
Both the steel and concrete silos have arrangements to
withdraw coal through the bottom of the silos. These may
be either in the form of a surface conveyor or a buried
conveyor arrangement. A sloped steel plate or treated
earth fill in the bottom of the silos assures total
recovery of the coal by using gravity. Larger diameter
silos or bins 100 feet in diameter, for example, generally
have more than one feeder chute at the bottom as shown
in Figure 9-6.
285
-------
BinFMd
StttlRoof
lOCkf'Dio.
ConcrtU Bin
9000 Tent Copoeity
PLAN SHOWING FEEDER ARRANGEMENT
<-ColltchngB.il
TVTtCAL SECTION THRU ENCLOSED STORAGE BIN
Figure 9-6
Monolithic Concrete Bin
The past trend in the industry was towards a cluster
of smaller (1,500 to 2,000 tons per silo) concrete silos.
These were generally of the precast stave-type silos,
were less expensive than the larger>monolithic bin types
and provided considerable flexibility in blending the final
product. Some recently built unit train facilities employ
as many as five or more silos at a single site. However,
the current trend is to a single larger storage silo as
depicted in Figure 9-6.
Though occasionally used for clean coal storage, the
rectangular-type bin has found only limited application.
However, these bins are used for flood-loading or choke
loading unit train cars from other types of storage
facilities. This type of bin is commonly built at the same
capacity as the hopper cars being loaded. They do vary
in capacity, but the majority of rectangular bins are under
200 ton capacity. A typical installation is shown in
Figure 9-7.
286
-------
Figure 9-7
Flood Loading From Steel Surge Bin
In contrast to open storage facilities, enclosed
storage facilities practically eliminate blowing dust and
windage losses and protect the clean coal from the elements
Additionally, these facilities provide nearly 100% live
storage of clean coal and eliminate all the pollution pro-
blems associated with coal storage.
9.3 CLEAN COAL HANDLING
Most coal handling systems incorporate a storage
arrangement to provide several thousand tons live storage.
This is critical when systems such as the unit train are
being used which require a rather rapid loadout. The
development of the unit train with its attendant economics,
more than any other factor, has contributed to the
widespread construction of storage and high-speed loading
facilities. As this is the most prevalent of today's
systems, primary emphasis will be placed on it during the
287
-------
following discussions. Other systems employ waterborne
loading, as in the use of barge haulage, and slurry pipe-
lines, although this system is not practiced widely as yet,
9.3.1 Unit Train Loading
The unit train has been defined as a complete train
of conventional size and equipment operating on a regu-
larly scheduled cycle movement, with dedicated or private
cars and assigned locomotives, between a single origin and
a single destination. The typical unit train loading
facility in the United States has a load-out, capacity of
3,000 to 3,500 tons per hour, with a maximum to date of
11,000 tons per hour at one installation. Though the
railroads handle larger trains over the road, the largest
usually placed for loading at mines is around 10,000 tons,
with the smallest ranging from 3,000 to 3,500 tons. The
number of cars using a single track loading ranges from
30 or 40 to over 100 cars. Specially designed cars for
unit train service are being used in increasing numbers.
The size of special experimental cars has reached 240 tons.
Single track loading is the general rule. However,
two loading tracks are used in some layouts with a maximum
ranging up to six. With few exceptions, car loading is
done from an overtrack surge'hopper ranging in capacity
from 85 to 300 tons. Flood loading rates may exceed 3,000
tons per hour. Where more than one silo or row pile is
operated, each has its own complement of feeders—in the
case of silos, usually 6 to 8 feeders are strategically
located across the bottom. In one installation located
over a train sized tunnel, only one chute per cone is
required to load at the rate of 6,000 tons per hour.
Another installation, shown in Figure 9-8, utilizes
two adjacent silos with a single pass-through tunnel for
288
-------
loading a 94-car unit train. The cars are 100 tons
capacity and the entire load-out can be accomplished in
under two hours. The locomotive first backs the empty
cars through the tunnel, and when the direction is
reversed, loading commences continuously until the entire
train has been loaded. An operator controls the feed
chute, which serves to contour the load as well as control
dust and constant loading conditions.
Figure 9-8
Two-Silo Unit Train Loading System
289
-------
There are basically three approaches used in the
loading of unit trains: locomotive, car haul and tripper
conveyor. The first system is the fastest, whereby
conventional locomotives move the cars in one pass on one
or more parallel tracks. The surge bin used has a capacity
of around 1 1/2 times that of the railroad cars. As the
cars move under the load point, the loading chute or chutes
can be lowered to permit flood loading and contour control.
Figure 9-9
Minimal Unit Train Loading Facility
The car haul system consists of a reversible double-
drum hoist with haulage ropes leading to dummy cars on the
end of both strings of cars. One string of cars is moved
in one direction and loaded while the other string is
simultaneously moved in the opposite direction. Upon
completion of car loading in one direction, the hoist is
reversed and loading commences in the opposite direction.
290
-------
Figure 9-10
Maximized Unit Train Loading Facility
Loading cars are normally removed and replaced with empties
before the car haul begins in opposite directions to reduce
the load on the hoist.
Figure 9-11
Car Haul System of Unit Train Loading
Source: McNally-Pittsburg
291
-------
The third system is one in which the train remains
stationary while being loaded by a movable tripper running
parallel to the train. Two strings of cars are positioned,
one on each side of the tripper. As the tripper completes
loading of one string it reverses the direction and begins
loading the other string. Meanwhile, the loaded string of
cars is removed and replaced with an empty set.
Figure 9-12
Unit Train Loading With Movable Tripper
Source: McNally-Pittsburg
In a variation of unit train loading, a stacker/re-
claimer can be used to load directly from an open storage
pile onto a conveyor which is discharged by the use of a
movable tripper. A stacker/reclaimer is shown in operation
in Figure 9-3.
A particularly efficient operation at the York Canyon
Mine near Raton, New Mexico, was built by McNally-Pittsburq
292
-------
(Figure 9-13). This system loads 84 gondolas in less than
two hours. As the gondolas pass through a tunnel under-
neath the conical coal stockpile, a hydraulically activated
gate and chute load the 100 ton cars. The system is
estimated to haul 700,000 tons of bituminous coal per
year.
9.3.2 Barge Loading
As with unit train loading, flood loading of barges
involves both silo and ground storage of the coal, usually
in the higher ranges of capacity. For example, 14,000
tons for a single silo and 75,000 tons for a ground storage
facility, fed by a traveling stacker. Loading rates of
5,000 tph will permit loading of 15 barges in less than
5 hours.
Barge loading has enjoyed an increase in popularity
during recent years for several reasons. This is a low-
cost shipping method which is becoming more efficient as
the waterway systems and equipment are improved. There
are numerous varieties of loading systems employed for
barge loading, generally paralleling technologies used for
unit train loading. For example, Figure 9-14 shows barge
loading using a movable tripper with telescoping chute
to control dust loss and load contour characteristics.
Five basic types of barge loading plants are encoun-
tered as follows:
A simple dock from which trucks dump directly
into the barge.
A stationary-chute type which works well where
river fluctuations are not too great and banks
are steep.
An elevating-boom type where the barges moved
back and forth in the river beneath. The
elevating boom allows more loading time if river
293
-------
ro
O
J.J. DAVIS
ASSOCIATES
Unit Train Being
Loaded Out In A
Western Mine
Figure 9-13
DRW
-------
elevations change greatly. This type is advan-
tageous where the river bank is a considerable
distance from the loading channel since the
elevating boom and conveyor belt can be combined
to span the shallow water area adjacent to the
river bank.
Floating-barge type, with the loading boom
mounted on a floating, or spar, barge and
pivoted for easier loading. This unit requires
a steep bank or fill to permit retraction and
extension of the main conveyor with changes in
the water level.
A tripper-conveyor type, in which the barges are
stationary and the loading chute moves back and
forth to load thus eliminating barge shifting
during loading.
Figure 9-14
Barge Loading with Movable Tripper
Source: McNally-Pittsburg
Figure 9-15 depicts three different barge loading facili-
ties. The first, a dock loading facility, the second, an
elevated trans-waterway facility, and the third, a unit-
barge facility.
295
-------
•• «.
-.:'
Figure 9-15
Various Barge Loading Facilitii
296
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9.3.3 Slurry Pipeline
Coal slurry pipelines have been proposed as a low cost
and environmentally sound method of moving coal. Unless
the length of haul exceeds 500 miles, the problems of water
supply, pipeline right of way, dewatering and costs of
facilities cannot be justified. However, one slurry pipe-
line is in continuous successful use in Arizona. On the
other hand, if coal is desulfurized by some physical coal
preparation technique resulting in a finely ground wet
product, a pipeline may be a feasible choice for transport-
ing the coal.
297
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REFERENCES AND/OR ADDITIONAL READING
Bechtel, Inc., "Coal Slurry Pipeline—An Environmental Answer", San
Francisco, California
Blankenship, R.E., "Operational and Environmental Features of Virginia
Pocahontas No. 3 Preparation Plant", Mining Congress Journal,
April 1973
Charmbury, H.B., "Mineral Preparation Notebook", Pennsylvania State
University
Coal Age, "Coal Preparation and Unit-Train Loading", July 1972
Coal Age, "The Coming Surge in Coal Preparation", January 1976
Coal Age, "Consol Preparation Confirms Coal Quality", October 1972
Coal Age, "Peabody Pioneers in Coal Handling & Preparation", Model
Mining Issue, October, 1971
Coal Age, "Rail Transport Dominates...", Mid-May 1975
Coal Age, "U.S. Steel Coal Preparation", Model Mining Issue,
October 1973
Coal Age, "Using Waterways to Ship Coal", July 1974
Consolidation Coal Company, "Conveying a Slurry Through a Pipeline",
British Patent #861-537, February 1961
Cook, L., "Practical Application of Hydraulic Mining at Rahui Buller
Coalfield", Paper 31, Mining Conference, School of Mines & Metallurgy,
University of Otago, May 1953
Cooper, Donald K., "Coal Preparation - 1974", Mining Congress Journal,
February 1975
Dahlstron, D.A.,; Silverblatt, C.E.,"Dewatering of Pipeline Coal",
U.S.A., Australian Coal Conference
Daub, Charles H., "The Oneida Plant", Mining Congress Journal, July 1974
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - S0_ Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
298
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Dokunin, A.V.; Onika, D.G., "Hydraulic Underground Mining", Translated
for Branch of Bituminous Coal Research, Division of Bituminous Coal,
U.S. Bureau of Mines
Goodridge, Edward R., "Duquesne Light Maximizes Coal Recovery at its
Warwick Plant", Coal Age, November 1974
Gospodarka, Gornictwa, "Possibilities of Mechanical Preparation
Underground", 1956 No. 4
Gvpzdek, G.; Macura, L., "Hydraulic Mining in Some' Deep Pits in
Czechoslovaki", " Translated by National Coal Board (A 1683), Uhli
#12, December 1958
Humboldt-Wedag, "Manufacturers Brochures", Cologne, Germany
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Provence Coalfield", France, Australian Coal Conference
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracity in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Jeffrey Mining Machine Co., "Jeffrey Mining Machine Company: Manu-
facturers Information", Columbus, Ohio
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
Korol, Dionizy, "Influence of Hydraulic Getting on Mechanical Coal
Preparation", Przeglad Gorniczy, Year 12 #12, December 1956
(National Coal Board Translation Section)
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Llewellyn, Robert L., "Coal Preparation", Elements of Practical Coal
Mining, Seeley W. Mudd Series, American Institute of Mining,
Metallurgical and Petroleum Engineering, Inc., New York, 1968
Lotz, Charles W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Martinka, Paul D.; Blair, A. Ross, "Western Coal Transportation - A
Challenge", American Mining Congress Convention, October 1974
299
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Roberts & Schaefer Company, "Manufacturers Information Booklets",
Chicago, Illinois
Tieman, John W., "Chemistry of Coal", Elements of Practical Coal Mining,
Seeley W. Mudd Series, American Institute of Mining, Metallurgical
and Petroleum Engineering, Inc., New York 1968
Wemco Division, "Manufacturer's Catalog", Envirotech Corporation,
Sacramento, California, 1974
300
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10. REFUSE HANDLING
10.1 OVERVIEW
Coarse refuse material is transported by a variety of
materials handling systems, singly and in combination with
others. A listing of the systems includes:
aerial tram,
conveyors, both belt and metal pan,
trucks, both end and bottom dump,
side dump mine cars,
scrapers and
bulldozers.
As with mine development refuse, the majority of
operators in the past have transported and deposited coarse
refuse under relatively uncontrolled conditions. Little
or no attention was given to effective compaction or other
density control methods. Water content depended upon that
which came from the plant, along with additions or remov-
als from the dump surface in conjunction with current
weather conditions. Placement, drainage and stability have
usually been a matter of circumstance.
When controlled placement of coarse refuse is in
effect, however, the materials handling system might
include modifications such as intentionally routing the
trucks to all areas of the dump in order to achieve some
301
-------
surface compaction, the utilization of conventional
compactors and rollers, control of placement to achieve
drainage and stability, etc. When this is done, however,
construction control techniques often predominate over the
density or related technical control procedures, resulting
in an improved but not necessarily adequate structure.
The placement of fine size coal refuse is almost
exclusively by hydraulic methods, that is, materials
pumped from the preparation plant to a settling pond.
When the settling pond is the final disposal site for the
fine refuse, control of the placement consists of varying
the location of the discharge of the pipeline since the
coarser particles will settle closer to the discharge
point, and the fine particles further away where the
ponding of the water is occurring. The effect of the
point of discharge, with the resulting segregation, can
be of significant importance to the stability of an im-
poundment. In recent years, incised ponds adjacent to
the preparation plant have been utilized for plant water
clarification, particularly where process equipment such as
thickeners can perform the primary solids removal work.
These ponds are usually of a smaller volume than the con-
ventional refuse embankment impoundments, and must be
cleaned periodically of the settled solids. This method
requires an excavator, such as a dragline or a front end
loader to load the settled materials for haulage to the
final disposal site. The treatment or utilization of
the fine materials at the dump or embankment then depends
upon the method of construction in use at the site.
10.2 MATERIALS HANDLING
With increased emphasis on clean fuels coupled with
technologically sophisticated extraction practices, the
percent of material discarded as refuse per ton of mined
302
-------
materials has increased. Presently more than 20 percent of
the total raw coal production is considered refuse. This
figure is increasing and may reach as high as 40 percent by
1980 according to industry estimates.
10.2.1 Refuse Handling by Aerial Tramway
Aerial tramway handling is widely used in the hilly
Appalachian coal fields. Preparation plants in this
region are commonly situated in the valleys, and the
disposal areas are usually over the top of the adjacent
hills. Aerial tramways are ideal in this application
since many times the slopes are too great for truck dispos-
al methods.
Tramcar sizes vary in capacity from 10 to 90 cu. yds.
and are able to travel at rates of up to 1750 fpm. Tram-
ways seldom are operated at less than 1000 fpm. This type
of system hauls and dumps the refuse at any point below
the track cables. The system is set up so as to be "fail
safe" enabling the tramway to stop in case of any
malfunction.
10.2.2 Refuse Handling by Belt Conveyor
The use of a belt conveyor system for refuse handling
involves the removal of refuse via the belt to a location
adjacent to the disposal area where it is distributed by
truck, scraper loader or stacker units. Bins are used at
the discharge end if the truck or scraper loader distribu-
tion is being used, but these are not necessary when
stacker distribution is being used.
Belt conveyors are able to attain high tonnage rates
over grades which would make wheeled vehicles inefficient.
However, use of belt conveyors should be evaluated
carefully since the cost per ton mile tends to remain
constant no matter how far the belt is extended, whereas
303
-------
COMBINED STORAGE CAPACITY
OF BOTH LEGS
22.000,000 TONS
OPERATING RATE 225 T.PH.
PROFILE
Figure 10-1
Continuous Aerial Tramway
Source: Interstate Equipment Corporation
the cost per ton mile for wheeled vehicles tends to
decrease as the haulage distance increases.
Continuous combination conveyor systems are used at
many installations, consisting primarily of a conveyor
and elevator arrangement. These units operate in one
direction and are able to negotiate slopes in excess of
30 degrees. The carriers range in capacity from 6 to 10
cu. yds. and the tramways are generally operated at speeds
between 400 and 600 fpm.
Belt size is dependent on factors such as desired
refuse removal rate, refuse characteristics (e.g., density
and flowability) and haul profile. Also, various idler
configurations are available. Conventional three-roll
idlers are provided in widths from 18 through 72 inches.
They are commonly spaced at 4 to 5 feet intervals on
channel or truss frames. Figure 10-3 shows a cross section
view of a three-roll idler belt arrangement.
304
-------
Figure 10-2
Three-Roll Idler Conveyor Belt System
A common feature of refuse disposal conveyor belts is
the turned-over or reversed-return run where the belt is
mechanically twisted to prevent the wet, refuse-carrying
side from contacting the return idlers. This provides
advantages such as decreased wear on the return idler
shell, prevents build-up of wet sticky material on the
return idlers and consequent adverse effect on belt
alignment, and prevents deposition of carry-back material
along the beltway.
10.2.3 Vehicular Haulage Units
Trucks and scraper loaders have long been used to
disperse material at the immediate disposal area. Trucks
are also being used increasingly as primary haul units
from the plant to the disposal area, mainly due to the
increased sizes of trucks now available. Three types of
vehicles are suitable for refuse disposal:
rear dump trucks,
side dump trucks and
scraper loaders.
305
-------
Each vehicle type has the advantage of being able to
spread the refuse thinly over the disposal area, a manda-
tory requirement for many of today's disposal areas.
Compaction of the disposal area is facilitated by driving
these vehicles over the area while discharging the loads.
Using haulage units such as trucks for refuse disposal also
provides greater flexibility; for example, dependency on a
single unit, as in conveyor disposal, is greatly reduced
when two or more trucks are used for primary refuse
haulage. The disposal pattern can also be more readily
adjusted to conform to natural contours, to develop
stability or to gradually raise the level of the area
above the existing landscape. Moreover, the capacity of
the system can be increased simply with the addition of
another unit.
To achieve these advantages, a common contemporary
practice is using a combination of truck and belt conveyor
transport for refuse handling. The belt is extended as
far as is economically feasible, many times right to the
disposal site. The belt discharges into a surge bin
which is then used for loading the trucks or scrapers.
Figure 10-4 depicts such a setup.
Another method of refuse handling is through slurry
pipelines. This method has received more emphasis in
recent years as the laws and regulations dealing with
stream pollution have become more stringent. In general,
greater use of hydraulic disposal is made for fine size
refuse than for coarse refuse, primarily because of the
high pressure head necessary to transport the coarse
refuse through long lengths of pipe at steep grades.
306
-------
Figure 10-3
Combination Conveyor
and Truck Refuse Handling System
307
-------
REFERENCES AND/OR ADDITIONAL READING
Bisselle, C.A.; Haus, S.A.; Lubore, S.H.; Scholl, M.M.; & Wilcox, S.L.,
"Strategic Environmental Assessment System: Initial Analysis of
Environmental Residuals", The Mitre Corporation, February 1973
Black Sivalls & Bryson, Inc., "Study of Sulfur Recovery from Coal
Refuse", U.S. Government Printing Office, September 1971
Charmbury, H.B., "Mineral Preparation Notebook", Pennsylvania State
University
Chemical Construction Corporation, "The High Sulfur Combustor - A Study
of Systems for Coal Refuse Processing", New York, New York,
February 1971
Coal Age, "Coal Preparation and Unit-rain Loading", July 1972
Coal Age, "The Coming Surge in Coal Preparation", January 1976
Coal Age, "Consol Preparation Confirms Coal Quality", October 1972
Coal Age, "Peabody Pioneers in Coal Handling & Preparation", Model
Mining Issue, October 1971
Coal Age, "U.S. Steel Coal Preparation", Model Mining Issue,
October 1973
Consolidation Coal Company, "Conveying a Slurry through a Pipeline",
British Patent #861-537, February 1961
Cook. L., "Practical Application of Hydraulic Mining at Rahui Buller
Coalfield", Paper 31, Mining Conference, School of Mines & Metallurgy,
University of Otago, May 1953
Cooper, Donald K., "Coal Preparation - 1974", Mining Congress Journal,
February 19J5
Dahlstron, D.A.; Silverblatt, C.E., "Dewatering of Pipeline Coal",
U.S.A., Australian Coal Conference
D'Appolonia, E., "Engineering Criteria for Coal Waste Disposal", Mining
Congress Journal, October 1973
Daub, Charles H., "The Oneida Plant", Mining Congress Journal, July 1974
Dean, K.C.; Havens, Richard; Glantz, M.W., "Methods and Costs for
Stabilizing Fine-Sized Mineral Wastes", U.S. Bureau of Mines RI 7896
1974
308
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Dokunin, A.V.; Onika, D.G., "Hydraulic Underground Mining", Translated
for Branch of Bituminous Coal Research, Division of Bituminous Coal,
U.S. Bureau of Mines
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Refuse Bank & Mine Fires",
EPA-670/2-74-009, February 1974
Fairhurst, Charles, "European Practice in Underground Stowing of Waste
from Active Coal Mines", First Symposium on Mine and Preparation
Plant Refuse Disposal, Louisville, Kentucky, October 1974
Falkie, Thomas W., "Overview of Underground Refuse Disposal", Coal and
the Environment Technical Conference, October 1975
Goodridge, Edward R., "Duquesne Light Maximizes Coal Recovery at its
Warwick Plant", Coal Age, November 1974
Gospodarka, Gornictwa, "Possibilities of Mechanical Preparation Under-
ground", 1956 No. 4
Gvozdek, G.; Macura, L., "Hydraulic Mining in Some Deep Pits in
Czechoslovakia", Translated by National Coal Board (A 1683), Uhli
#12, December 1958
Huraboldt-Wedag, "Manufacturers Brochures", Cologne, Germany
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Provence Coalfield", France, Australian Coal Conference
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracity in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Jeffrey Mining Machine Co., "Jeffrey Mining Machine Company: Manu-
facturers Information", Columbus, Ohio
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
309
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Knuth, William M., Jr.; Charbury, H. Beecher, "Remote Sensing Techniques
for Analyses of Burning in Coal Refuse Banks", Coal and the Environ-
ment Technical Conference, October 1974
Korol, Dionizy, "Influence of Hydraulic Getting on Mechanical Coal
Preparation", Przeglad Gorniczy, Year 12 #12, December 1956
(National Coal Board Translation Section)
Kosbwski, Z.V., "Control of Mine Drainage from Coal Mine Mineral
Wastes, Phase II - Pollution Abatement & Monitoring", EPA 42-73-230
May 1973
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Leven, P,, "Pumping: A Good Way to Dispose of Coal Plant Refuse",
Coal Mining and Processing, June 1966
Lotz, Charles W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Magnuson, Malcolm 0.; Baker, Eugene C., "State-of-the-Art in
Extinguishing Refuse Pile Fires", Coal and the Environment Technical
Conference, October 1974
Martin, John F., "Quality of Effluents from Coal Refuse Piles", Coal
and the Environment Technical Conference, October 1974
Moulton, Lyle K.; Anderson, David A.; Hussain, S.M.; Seals, Roger K.,
"Coal Mine Refuse: An Engineering Manual", Coal and the Environment
Technical Conference, October 1974
National Coal Association, "First Symposium on Mine & Preparation Plant
Refuse Disposal", Coal and the Environment Technical Conference,
October 1974
Patterson, Richard M., "Closed System Hydraulic Backfilling of Under-
ground Voids", First Symposium on Mine and Preparation Plant Refuse
Disposal. Coal and the Environment Technical Conference, October
1974
Poundstone, William, "Problems in Underground Disposal in Active Mines",
First Symposium on Mine and Preparation Plant Refuse Disposal,
Coal and the Environment Technical Conference, Louisville, Kentucky,
October 1974
310
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Roberts & Schaefer Company, "Manufacturers Information Booklets",
Chicago, Illinois
Scott, Robert B., "Sealing of Coal Refuse Piles", Program Element
1B2040, NERC-USEPA, Cincinnati, Ohio, July, 1973
Shields, Donald H., "Innovations in Tailings Disposal", Coal and the
Environment Technical Conference, October 1974
Wahler, William A., "Coal Refuse Regulations, Standards, Criteria and
Guidelines", Coal and the Environment Technical Conference,
October 1974
Wemco Division, "Manufacturer's Catalog", Envirotech Corporation,
Sacramento, California, 1974
Yusa, M.; Suzuki, H.; Tanaka, S.; Igarashi, C., "Sludge Treatment Using
A New Dehydrator", Japan, Australian Coal Conference
311
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312
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11. THE COMPLETE PREPARATION PLANT
11.1 OVERVIEW
For the purpose of clarity and to ease the understand-
ing of the very complicated and interdependent process of
the physical cleaning of coal, the discussion heretofore
has addressed the individual process modules within the
preparation plant. However, to gain a complete
understanding of the physical coal cleaning process and
its related costs, it is necessary to look at the -
preparation plant as a unitized entity.
As the pressures mount to preserve an acceptable
environment and because the oxides of sulfur (principally
sulfur dioxide (802) that comes from the burning of
sulfur-bearing coal and oil in stationary sources) ranks
second in total quantity of pollutants discharged into
the atmosphere, coupled with the projected significant
increase in the quantity of coal to be consumed annually,
it is readily apparent that a substantial reduction in
the amount of S02 emitted to the atmosphere must be
achieved. Studies conducted by the U.S. Environmental
Protection Agency and the U.S. Bureau of Mines have
indicated that relatively few American coals from the
Eastern and Midwest coal producing areas may be cleaned
to relatively low sulfur levels, i.e., to about one
percent of total sulfur content, by the utilization of the
best available physical coal preparation technology (see
Chapter 4). Table 11-1 shows the percent of samples
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from the four major coal producing areas that will meet
the EPA standard of 1.2 Ibs S02/MBtu.
Table 11-1
Percent of Coal Samples Meeting EPA Standards
of 1.2 lbs/SO2 per MBtu*
Region
Northern Appalachian
Southern Appalachian
Midwest
Western
% Meeting
31
63
4
98
* Based on crushing to pass 14-mesh and cleaning
at a 50% Btu recovery.
As noted in Chapter 4, The Preparation Process, the
range of coal cleaning practices in the United States is
very broad; from no preparation and direct utilization of
run-of-mine product to multi-stage cleaning with controlled
particle size, maximum ash and pyritic sulfur removal,
extensive dewatering including thermal drying, maximum
calorific content and maximum product recovery. It is,
however, anticipated that the majority of new preparation
plants built will approach the maximum designed
capability for ash and pyritic sulfur removal and will,
therefore, fall into Level 4 as defined in Chapter 4. It
is imperative, then, that a discussion of a complete
"unitized" preparation plant address a maximized plant.
11.2 THE COMPLETE PLANT
Figure 11.1 is a flow chart for a typical, modern
preparation plant as defined by Level 4 in Chapter 4.
The
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Flowchart for
a Complete
Preparation Plant
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diagram contains all of the elements of the process modules
defined in Chapter 4 and a majority of the equipment types
discussed in Chapters 5 through 10. Figures 11-2, 11-4
and 11-5 dissect Figure 11-1 and reduce it to the compo-
nents of the coarse, intermediate and fine size coal
cleaning circuits, respectively. By the selective elimina-
tion of first, the fine size coal cleaning circuit and
secondly, the intermediate size coal cleaning circuit, a
more complete understanding may be obtained for preparation
plants falling into Levels 3 and 2, respectively.
11.2.1 The Coarse Size Coal Circuit
Figure 11-2 highlights the coarse size coal circuit.
The run-of-mine coal enters the preparation plant area
at a truck or rail car dump or directly from the mine via
a belt conveyor. The ROM coal is conveyed directly to a
rotary breaker where its top size is reduced to 5 or 6
inches. All material which will not degrade in size to
5 inches or less is eliminated from the system without
further processing and transferred directly to the refuse
bin. The coal and associated impurities which have been
reduced in size to 5 inches or less are conveyed to the
raw coal storage facility (see Chapter 5, Raw Coal Storage
and Handling, for details). The ROM coal is stationary
while in storage. Upon entering the actual preparation
plant, the coal will remain in constant motion until it
completes its circuit and is once again stabilized in the
clean coal storage facility or, if refuse, until it reaches
its final destination in the refuse pile or slurry pond.
When the ROM coal enters the preparation plant from
the raw coal storage facility, it first encounters a raw
coal screen which begins the initial size separation
process. All coal larger than V is transmitted directly
to the pre-wet screen where it is hit with water sprays to
deslime (removal of the small particles sticking to the
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large particles and removal of silt and clays) the coal
and to thoroughly wet it to simplify the dense media
washing process. (See Chapter 6, Product Sizing, for
details.) The ROM coal smaller than %", including
the products carried by the water from the pre-wet screen
enters the intermediate size coal cleaning circuit.
The raw coal passing over the pre-wet screen is
transmitted directly to the Dense Media Separator where
raw coal separation is achieved through a closely con-
trolled specific gravity bath. All product (coal) with a
specific gravity of approximately 1.4 (in this case) floats
or remains in the top of the washer and all product heavier
than the 1.4 specific gravity settles and is removed by the
refuse removal system. (See Chapter 7, Product Separation,
for details.)
The overflow from the dense media washer (float
product) is conveyed directly to a clean coal screen where
the coal is first drained of the excess dense media (usually
magnetite) and then washed with clean spray water to remove
any of the dense media still clinging to the coal. The clean
coal is then dewatered by the vibrating action of the screen.
The refuse product of underflow from the dense media washer
is conveyed directly to a refuse screen where it is first
allowed to drain. The refuse is then washed with spray
water to remove any remaining dense media and finally
dewatered by the vibrating action of the screen and
conveyed directly to the refuse bin. (See Chapter 8,
Product Dewatering and Drying, for details.) The
underflow from the drain portion of both the clean coal
screen and the refuse screen is piped directly to the
dense media sump and returned to the dense media washer.
The underflow from the spray wash area of these screens
is piped to the rinse sump from which it enters the media
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recovery circuit discussed in Figure 7-16. Figure 11-3
illustrates the activities surrounding the clean coal and
refuse screens.
PIMPS
Figure 11-3
Highlights of the Drain and Rinse Process
in the Coarse Coal Circuit
The product (clean coal) from the top deck of the
clean coal screen (coal larger than % inch in this case) is
considered to have been sufficiently dewatered by the
screen, i.e., its surface moisture has been reduced to 10%
or less, and will, therefore, not require further dewaterr
ing. However, the coal larger than IV is usually reduced
to a smaller size before storage. In this example, the coal
oversize on IV screens is conveyed directly to a coal crusher
where its top size is reduced to IV or less. The product
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from the coal crusher is conveyed to the clean coal
storage facility. (See Chapter 9, Clean Coal Storage
and Handling.)
11.2.2 The Intermediate Size Coal Cleaning Circuit
The intermediate size coal cleaning circuit is defined
as that portion of the preparation plant that cleans coal
smaller than 3/4 or 1/2 inch, but generally larger than
48-mesh. As pointed out in Figure 11-4/ which highlights
the intermediate size coal cleaning circuit, the circuit
in this example may be considered as having three
individual points of origin:
the underflow of the raw coal screen,
the underflow of the pre-wet screen and
the product of the second or bottom deck of the
clean coal screen in the coarse coal circuit.
As discussed in earlier chapters and as shown in Figures
11-4 and 11-5, there is considerable overlap of equipment
and functions within the preparation plant. For the purr
pose of clarity, every attempt is made to keep the
discussion confined to the linear flow. It should be kept
in mind that the flow is not always linear and that the
flow may in fact backtrack upon itself and that the
definitive and arbitrary ground rules for describing the
coarse, intermediate and fine size coal circuits are
highly flexible and subject to a multitude of variables
and interpretations.
Referring to Figure 11-4, the underflow from the raw
coal screen contains the majority of the ROM feed stock
that is 3/4" or smaller in size. This underflow slurry
is piped directly to a sieve screen where a separation is
made at 28-mesh. The overflow from the sieve screen
(particles larger than 28-mesh) is transported to the
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J.J.DAVIS
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Flowchart for
Intermediate Size
Coal Circuit
-------
distributors for the concentrating tables. The underflow
from the sieve screen is piped to the hydrocyclone sump
which in this example is considered to be in the fine size
coal cleaning circuit.
A second point of entry to the intermediate size coal
cleaning circuit is the underflow from the pre-wet screen
in the coarse size coal circuit. This underflow contains
the balance of particles smaller than 3/4" or V contained
within the raw coal feed and that which has developed from
size degradation during the initial screening process. The
pre-wet screen underflow product reports directly to the
distributor boxes for the concentrating tables. Refer to
Chapter 6 for details of the product sizing process module.
The distributor boxes which collect the overflow from
the sieve screen and the underflow from the pre-wet screens
evenly distribute the combined products to 20 concentrating
tables where the clean coal is collected as a product along
the long side of the table, and the refuse product is
collected along the short side of the table (see Chapter
7 for details). The refuse product, being a fairly coarse
slurry (28-mesh or larger) is fed to a screw classifier
where the solid product is collected and conveyed to the
refuse bin. The remaining slurry of water and ultra-fine
refuse product is piped to the static thickener for
settling and eventual disposal. The clean coal product,
on the other hand, is fed to a sieve bend to begin its
dewatering and drying cycle. The sieve bend will make a
separation at approximately 28-mesh with the overflow going
to a centrifugal dryer and the underflow reporting to the
fine size coal cleaning circuit.
The third entry point to the intermediate size coal
cleaning circuit in this example is the product of the
second deck of the clean coal screen in the coarse size
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coal circuit. The clean coal product from the bottom deck
of the clean coal screen is conveyed directly to the cen-
trifugal dryers. This product is usually one inch or
smaller in size. As noted, the parameters of the inter-
mediate size coal cleaning circuit generally refer to 3/4"
or V and smaller particles. However, at this point in
the process module the coal has been cleaned within its
appropriate process module and is being combined during
the dewatering and drying process group. As pointed out in
Chapter 8, the percent of surface area increases as the
product size decreases. As the percentage of surface area
increases, the moisture retention per unit weight increases.
The surface moisture of the top deck product of the clean
coal screen has been reduced to 10% or less; however, the
surface moisture of the bottom deck product may be as high
as 30% or more necessitating an additional dewatering and
drying step.
The slurry overflow product (moisture and ultra-fines)
from the individual centrifugal dryers is piped directly
to the effluent sump from which it enters the fine size
coal cleaning circuit. The centrifugal underflow product
as depicted in Figure 8-13 is conveyed to a thermal dryer
for final drying (see Chapter 8 for details). Upon
completion of the thermal drying process, the intermediate
size clean coal product is combined with the coarse size
coal product in the clean coal storage facility.
11.2.3 The Fine Size Coal Cleaning Circuit
Figure 11-5 highlights the fine size coal cleaning
circuit in the exampled preparation plant. For the purpose
of this discussion, the fine size coal cleaning circuit is
defined as that portion of the preparation plant coal
washing circuit that processes coal and refuse products
28-mesh or smaller. It must be noted that all of the
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equipment contained within this description with the
exception of the froth flotation module may be classified
as belonging to the intermediate size cleaning circuit in
a different example, i.e., a metallurgical coal cleaning
plant which produces a low sulfur clean coal product as
well as a high sulfur middlings product.
As may be observed from Figure 11-5, the fine size
coal cleaning circuit feed has three points of origin:
1. the underflow from the initial sieve screen in
the intermediate size coal cleaning circuit,
2. the underflow from the sieve bend screening of the
concentrating tables' clean coal product slurry and
3. the slurry and ultra-fine effluent from the
centrifugal dryers.
In this example, the largest portion of feed stock for the
fine size coal cleaning circuit comes from the underflow
of the initial sieve screens in the intermediate size coal
cleaning circuit. This slurry of coal and refuse flows by
gravity to a hydrocyclone sump on the bottom floor of the
preparation plant where it is pumped to hydrocyclones for
hydraulic product separation as discussed in detail in
Chapter 7. The underflow (refuse) from the large hydro-
cyclones is piped to a screw classifier where it mixes
with the reject product from the concentrating tables and
is subsequently removed to the refuse pile or slurry pond
as previously described or, more typically, this underflow
would be retreated on the tables or in a dense-medium
cyclone. The overflow clean coal product (approximately
65% of the feed solids) is piped to the cyclone sump where
it is collected and pumped to a bank of 10" classifying
cyclones which make a product separation at approximately
48-mesh. Coal particles smaller than 48-mesh are contained
in the overflow. The underflow product is routed directly
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to the vacuum filter for recovery and initial dewatering
(see Chapter 8). The overflow product is piped to a split-
ter box which feeds the froth flotation circuit. (Note:
Flotation circuits typically treat 28-m x 0, 48-m x 0 or
100-ra x 0.)
The second point of origin for the fine size coal
circuit is the underflow from the sieve bend which is the
initial dewatering device for the clean coal product of
the concentrating table module. The third point of origin
for the fine size coal cleaning circuit is the effluent
slurry from the centrifugal dryers. The ultra-fine coal
slurry products of the sieve bend and the centrifugal dryers
are piped to the effluent sump from which they are pumped to
the bank of clean coal classifying cyclones. The overflow
from these cyclones reports to the froth flotation module
and the underflow, 48-mesh or larger, reports to the vacuum
filter module for recovery.
The minus 48-mesh size cyclone overflow products
collected in the splitter box are equally distributed by
the splitter box to the various froth flotation cell groups.
In a single stage froth flotation circuit, the float
product is skimmed off the top of the cells as the clean
coal product and is piped to the vacuum filter for initial
recovery and dewatering. The sink product or refuse efflu-
ent is piped to a static thickener for recovery and dis-
posal. In the U. S. Bureau of Mines two-stage froth
flotation process, the float product is piped to a second
set of froth cells where the sink product (clean coal) is
routed to the vacuum filter module and the float product
(pyrite) joins the sink product (refuse) of the first stage
flotation cells aftd is piped to the static thickener (review
Chapter 8 for details).
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The product recovered by the vacuum filter (described
in Chapter 8) is conveyed to the thermal dryer where it
joins the clean coal product of the intermediate size coal
circuit for final drying. Upon completion of the thermal
drying operation, this combined clean coal product joins
the clean coal from the coarse and intermediate size coal
cleaning circuits in the clean coal storage facility.
11.2.4 The Refuse Recovery Circuit
Figure 11-6 highlights the refuse recovery circuit of
this particular flowsheet. The recovery circuit is broken
down into four major areas:
1. solids recovery—dry,
2. refuse slurry concentration and solids disposal,
3. refuse slurry concentration and slurry disposal
and
4. dust collection and disposal.
The dry solids recovery and disposal is simple and
straightforward. The refuse solids are generated in the
coarse coal circuit (as noted in Section 11.2.1) as reject
material from the rotary breaker and as dewatered solids
from the coarse refuse screen. These solids are conveyed
directly to the refuse bin where they await transport to
the solids disposal area (see Chapter 10, Refuse Handling,
for details).
The refuse slurry and dry solids disposal circuit is
also straightforward. The water and refuse slurry from
both the hydrocyclone module and the concentrating table mod-
ule in the intermediate and fine size coal cleaning circuit
is piped directly to a spiral classifier. The classifier
concentrates the larger solids (plus 28-mesh) and dischar-
ges them to a conveyor system for transport to the refuse
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bin. The moisture carried out of the classifier is
collected via natural drainage during the conveying process
and piped to the static thickener.
The refuse ultra-fines, including the silt and clay
particles generated throughout the coal washing system,
are collected as a slurry underflow from the spiral classi-
fier or as a slurry underflow from the froth flotation
module. This slurry is piped directly to the static
thickener where it is concentrated with the aid of various
flocculants and piped in a highly concentrated slurry form
to the refuse pond. The clarified water overflow from the
static thickener is returned to the plant water system.
In a more sophisticated preparation plant, the thickened
concentrate underflow from the static thickener would be
routed to a refuse recovery vacuum filter and the filtrate
would be conveyed to the refuse bin for later transport
to the waste dump.
The dust collection system in this example consists
only of a dust collector and wet scrubber attached to the
thermal drying module. The slurry generated from the wet
scrubber is piped to the static thickener.
11.2.5 Process Quantities
To comprehend the physical coal cleaning process and
to obtain an overall perspective of the material flow
within the preparation plant, it is imperative that process
quantities expressed in terms of percent of total product
processed be understood. Table 11-2 summarizes the product
quantities found in Figure 11-7 by coarse, intermediate and
fine size coal circuits. These figures are based on a
ROM coal feed of 1000 tons per hour (tph) to a plant
utilizing 7070 gallons per minute (gpm) of process water
with a yield of 697 tph clean coal and 303 tph reject
material.
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o
Table 11-2
Process Quantities For a Typical 1000 tph Coal Cleaning Plant
Note: Reference Figures 11-1, 11-2, 11-4, 11-5 and 11-6
Coarse Size Coal
tph 1 % of Total
Washing Circuit
690 tph 69%
Dewatering Circuit
270 tph 38.7%
870 GPM 12.3%
Process Water
Intermediate Size Coal
tph % of Total
Washing Circuit
210 tph 21%
Dewatering and Drying
226 (From Coarse
Coal Circuit)
137 (From Concen-
trating Tables)
363 tph 52.1%
1860 GPM 26.3%
Process Water
Fine Size Coal
tph % of Total
Washing Circuit
100 tph 10%
Dewatering and Drying
47 (Classifying
Cyclones)
20 (Froth Flotation)
-3 (Dust Loss to
Thermal Dryer)
64 tph 9.2%
4340 GPM 61.4%
Process Water
Tot. tph
1000
697
303
1000
tph
Refuse
tph 1 % of total
Coarse Size
Refuse Recovery
190 tph 62.7%
Intermediate Size
Refuse Recovery
90 tph 29.7%
Fine Size
Refuse Recovery
20 tph 6.6%
Thermal Dryer Dust
3 tph 1.0%
Total Refuse
-------
A review of Table 11-2 shows that the coarse size
coal circuit processed 69% of the total plant feed with a
clean coal yield of 71% or 496 tph. The intermediate size
coal circuit washes 21% of the total plant feed with a
yield of 65% or 137 tph; however, the intermediate size
coal circuit must dewater and dry 52.1% of the total clean
coal yield. The fine size coal circuit washes 10% of the
total plant feed with a yield of 64% or 64 tph and dewaters
and dries 9.2% of the total clean coal yield. Figures
ll-7a, b and c graphically display the relative process
quantities (the thickness of the varying lines represents
the percentage of the total product being processed through
the coarse, intermediate and fine size coal circuits).
11.3 THE ECONOMICS AND MANAGEMENT OF COAL PREPARATION
Other than the general guidelines discussed in Table
4-1, it is beyond this discussion to outline or define
specific costs for the physical cleaning of coal (partic-
ularly in view of today's changing economy). However, a
general discussion of the economic aspects, design and
operational characteristics of coal cleaning plants may be
beneficial.
The overall economics and management of a coal
preparation facility are governed by a number of inter-
dependent parameters which individually and collectively
affect the final performance. A preparation plant's
benefit to the operator, and ultimately to the customer,
is measured through its return on investment. The
sensitivity analysis desplayed in Figure 11-8 and 11-9
shows how the various parameters affect the return on
investment through unfavorable change from planned or
expected values. As illustrated in Figure 11-8, for
metallurgical coals, the selling price negotiated is the
primary and most sensitive variable, followed by the yield,
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r
U)
U)
to
-------
mining costs and transportation. It is clearly indicated
that the ROI is the least sensitive to the coal preparation
plant capital and operating costs (overhead).
c»s[
S!HI«t MICE' TOI -174
Cintll IIVCSTIItlT-ISOII
NIIIIG COST/ UK- SISO
TIMSniMIIOI COST/ 101 'SS.JO
nriD » • >o
0*111(10 CIST/ Til- II. )i
I.O.I. • 11.4%
os to is ;o is
% UNFAVORABLE CHANGE FROM EXPECTED VALUE
Figure 11-8
Sensitivity Analysis for Metallurgical Coal
Source: Birtley Engineering, Salt Lake City, Utah
For energy (steam) coal, the selling price is
determined by heat energy content (x cents per million
Btu's) and is, therefore, not considered as an independent
variable. As Figure 11-9 illustrates, the transportation
333
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of the clean coal product is the major factor affecting the
level of income followed by yield and mining costs. Again,
the operational costs and capital investment are relatively
non-sensitive variables.
"o 5 ID is :e
% UNFAVORABLE CHANGE FROM EXPECTED VALUES
Figure 11-9
Sensitivity Analysis for Steam Coal
Source: Birtley Engineering, Salt Lake City, Utah
Most of the factors considered in Figures 11-8 and
11-9 are fixed and beyond the control of the preparation
334
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plant and, as shown, any change from the expected or
planned values dramatically impacts revenue and R.O.I.
However, one variable—clean coal yield—is to a great
extent controllable within the preparation plant. Once
the theoretical yield for a particular coal has been
determined, the optimum return is achieved by approaching
that recovery level as nearly as possible. Using the
standard case data presented in Figure 11-8 (selling price
of $35/ton for metallurgical coal), a one percent increase
in yield from 75% to 76% for a facility producing 2 million
tons of coal annually would result in a net revenue
increase of $700,000.
The optimization of the clean coal yield is dependent
upon successful design and operation of the preparation
plant. The most important step towards the ultimate
success of the plant is the selection of the flowsheet.
The actual design of the physical structure, the placement
of the equipment, the availability of an adequate water
supply, etc., are ancillary and are usually dependent upon
the process flow selected. In the selection of the flow-
sheet, several questions must be asked. The answers to
these questions must be clearly defined and well documented.
The most important questions are:
What are the properties of the raw coal?
What are the washability characteristics of the
raw coal?
Will further reduction of ash, sulfur or mois-
ture improve either the salability or the
realization?
11.3.1 Defining Properties of Raw Coal
Coals vary considerably in quality; therefore, it is
necessary to determine the properties of a given coal to
effectively evaluate its worth for a specific use.
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Electric utilities pay for coal on its effective heat value
with appropriate credits or penalties if the properties of
given clean coal vary from the established ash, sulfur or
moisture levels. Steel companies judge coal as to its
coking strength, expansion or swelling properties, ash-
sulfur-phosphorous-carbon content and how well it blends
with other coals to make a good coke.
In the establishment of the properties of a given coal
the coal is ordinarily analyzed first as to its "proximate"
or "ultimate" analysis:
Proximate Analysis—is used to determine the
moisture, volatile matter, ash content and fixed
carbon content of a specific coal.
Proximate Analysis, %
Moisture
Fixed Carbon
Volatile Matter
Ash
Total 100.0
The ash and moisture content are important
because they affect the heating value of the coal.
Additionally, the moisture content may influence
the capacity of the pulverizer used in pulverized
coal burning systems and the ash content is a
major contributor to slag in the blast furnace
and will remain in the coke in coking coals. The
volatile matter content reflects coke yield, is
an indicator of coke quality, is indicative of
the ignition temperature of the coal and corre-
lates with the amount of theoretical air need
for combustion and the fineness of pulverization
required for the most effective use of the coal
as a fuel.
Ultimate Analysis—is used to determine the
carbon, hydrogen, oxygen, nitrogen, sulfur and
ash content of a given coal. This analysis is
used in combustion calculations to determine air
requirements, and to obtain material balances
in boiler tests. The amount of sulfur in the
coal determines the air pollution potential and
336
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Ultimate Analysis, %
Carbon '
Hydrogen
Oxygen
Nitrogen
Sulfur
Ash
Total 100.0
the corrosiveness of the combustion products.
Additionally,,the sulfur content of the coal
used in steel making is apt to contaminate the
metal product.
The coal is further analyzed depending upon its end use by
any one or a series of tests as outlined by the following:
Calorific Value—is used to determine the calori-
fic or heating value of the coal expressed in
Btu's per pound of coal. The calorific value is
basic to obtaining heat balances in firing coal
to produce heat or steam and it is usually
specified in contracts for steam coal.
Coal-Ash Fusibility—measures the temperature at
which the coal-ash will soften and become fluid
when heated under prescribed conditions. The
type of burning equipment to be used governs the
desirability of using coals with either low or
high melting ash.
Coal-Ash Composition—is reported as metal oxides
and commonly included analysis for Si02/ Al2C>3,
CaO, MgO, Na20, K2<3 and P2°5 • Tne ash composi-
tion is important in boiler design and operation
and may be used as a guide in determining the
fouling or corrosion characteristics of a coal
or in predicting the ash-softening temperature.
Free-Swelling Index—is used to determine a
relative measure of the caking properties or
free burning quality of a coal. The term caking
refers to the fusion of the coal in a fuel bed
into a large coherent mass that interferes with
the uniform flow of air through the fuel bed and,
therefore, determines the type of burning
equipment to be used.
337
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Hardgrove Grindability Index-^-is a measure of the
hardness of a given coal or the ease with which
it may be pulverized.
Audibert-Arnu Dilatometer and Gieseler Plasto-
meter—tests are used to measure the plastic
properties of a coal which are related to the
viscosity of the fluid coal during the coking
process. The best coking blend contains coals
whose ranges of plasticity approximately
coincide.
11.3.2 Washability Studies
To determine the preparation method and the equipment
which is to be used to clean the coal (flowsheet develop-
ment) washability studies must be conducted to determine
the size and specific gravity distributions of the coal.
All of the coal washing processes discussed in this
presentation with the exception of froth flotation, effect
a separation between the coal and its related impurities
on the basis of the difference in the specific gravity of
their compcinents. Coals vary in the relative amounts of
material of different densities present, and it is this
factor that determines the washability or "upgrading" of
the specific coal. Washability studies, then, are
conducted to determine how much cleaned, salable coal can
be produced at a given specific gravity level and with what
degree of separation difficulty.
The washability studies of the specific coal are made
by testing the coal sample at pre-selected, carefully
controlled specific gravities. The specific gravity
fractions are collected, dried, weighed and analyzed
(generally) for ash and sulfur content. A table is
compiled showing the weight percent of each specific
gravity fraction, together with an analysis of that
fraction. The data are mathematically combined on a
weighted basis into "cumulative float" and "cumulative
338
-------
sink" and these combined data are used to develop the
"washability curves" that are characteristic for that coal.
This testing procedure is commonly termed float-and-sink
analysis, or specific gravity fractionation.
The washability curves shown in Figure 11-10 are
plotted from the data collected during the testing. Five
curves are generally drawn from the data: Specific gravity
(yield), cumulative-float ash, cumulative-sink ash,
elementary ash and +0.10 specific gravity distribution.
The most important of these curves are:
specific-gravity (yield),
cumulative float coal—ash and
plus and minus 0.10 near gravity material
distribution.
The specific-gravity (yield) curve is plotted directly
from the cumulative-percent weight float data and specific-
gravity fractions. This curve indicates the quantity of
clean coal that can be theoretically obtained by washing
at a certain specific gravity. The cumulative-float ash
curve is plotted directly from the cumulative percent
weight float and cumulative percent ash float and shows
the theoretical amount of ash content in a particular
quantity of floated coal. The +0.10 specific-gravity
distribution curve shows the percentage (by weight) of the
coal that lies within plus 0.10 and minus 0.10 specific-
gravity units at any given specific gravity. The plus
and minus 0.10 near-gravity material distribution curve
indicates the ease or difficulty of cleaning the particular
coal being evaluated.
11.3.3 Determining Economical Washing Specific
Gravities
As a general guide for determining the lowest practi-
cal specific gravity to wash a particular coal, especially
339
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100
+0.10 SPECIFIC-
GRAVITY I
IS. DISTRIBUTION
2.2 2.1 2.0 I 1.9 1.8 1.7
CUMULATIVE ASH, FLOAT
10 20 30 40 SO 60 70 60 90 100
CUMULATIVE ASH, SINK, AND ELEMENTARY ASH
Figure 11-10
Typical Washability Curves
when jigs and tables are used, it is oftentimes arbitrarily
designated that the point at which 10 percent of the total
raw coal feed lies within +_0.10 specific gravity of the
separating gravity is the lowest specific gravity at which
it is practical to operate a coal cleaning plant. Most
engineers will, therefore, utilize the +0.10 specific
gravity distribution curve as a starting point in predict-
ing the product that may be expected from a particular
coal. For example, referring to Figure 11-11 and assuming
a separation at 10 percent near-gravity material in the
float product, the following information may be obtained:
340
-------
+ 0.10 SPECIF 1C -
" GRAVITY I
STRI8UTION
100
0 2
I SPECIFIC
ID 12 14 j
ssi/ i i
CUMULATIVE ASH, FLOAT I
B
Figure 11-11
Determination of Economical Washing
Specific Gravities
By projecting downward from the +0.10 specific gravity
curve (Point A), it is determined that the separating
gravity for 10 percent near-gravity material in the float
product will be 1.48 (Point B); the yield or float product
will be 85.5% of the feed (Point C); the ash content of the
float product will be 5.8% (Point D).
A careful review of Figure 11-11 will show that if a
higher specific gravity is chosen at which to effect
separation of the coal and its related impurities, the
total ash content of the coal increases rapidly. If
a lower specific gravity is selected as the washing
gravity, then the percent of near-gravity material in the
341
-------
float product begins to reach totally unacceptable levels
for Baum jigs and tables, as defined in Table 11-3.
Table 11-3
Impact of Near-Gravity Material on the Separation
Process (for Tables and Baum Jigs Particularly;
Not for Dense Medium Processes)
Quantity Within +0.10 Specific
Gravity Range, percent Ease of Separation
0-7 Simple
7-10 Moderately Difficult
10-15 Difficult
15-20 Very Difficult
20-25 Exceedingly Difficult
Above 25 Formidable
11.3.4 Selection of the Process Flowsheet
A very good picture of the make-up of a specific coal
and the expected yield of an acceptable clean coal product
can be obtained from the test data as outlined in Sections
11.3.1, 11.3.2 and 11.3.3. Once the quantity (tons per
hour) of feed to the preparation plant and the size
constituents of the feed stock have been determined, the
test data are utilized to determine the preparation method
or methods. The preparation method combined with the
unique characteristics of the coal determine the equipment
which must be selected to produce an acceptable clean coal
product.
If, for example, the coal to be processed is easily
cleanable (low percent near-gravity material) with a low
sulfur content and fairly strong (does not degrade in size
during processing) and if the size consist of the feed
342
-------
stock is primarily limited to the coarse coal sizes (70-80%
over % in.)/ then probably a very straightforward flowsheet
can be selected. The coarse size of the feed will usually
permit sufficient drying by natural drainage and mechanical
dewatering eliminating the requirement for a thermal dryer.
The low sulfur content will eliminate the need to reduce
the size of the feed stock to liberate the pyrite. Without
a requirement to dramatically reduce the size of the feed
and with a low percentage of fines in the feed, an elabor-
ate and expensive fine coal cleaning system will not be
required.
On the other hand, if the feed has a high percent of
fines (due to the nature of the coal or the mining method)
of if the coal in question has a high sulfur content, then
a very complicated and interrelated flowsheet must be
selected to ensure an adequate yield with a clean coal
product of acceptable ash and total sulfur content.
As noted in Section 11.3, the clean coal yield is the
most sensitive factor in determining success or failure of
a particular coal preparation plant (as related to return
on investment). All of the variable discussed in Chapter 11
may directly affect the clean coal yield, and therefore the
flowsheet required for a particular coal will determine
whether or not that particular coal can economically be
provided to a particular customer.
343
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REFERENCES AND/OR ADDITIONAL READING
Bituminous Coal Research, Inc., "An Evaluation of Coal Cleaning
Processes and Techniques for Removing Pyritic Sulfur from Fine
Coal", BCR Report L-339, September 1969, BCR Report L-362, February
1970, BCR Report L-404, April 1971, BCR Report L-464, April 1972
Black Sivalls & Bryson, Inc., "Study of Sulfur Recovery from Coal
Refuse", U.S. Government Printing Office, September 1971
Blankenship, R.E., "Operational and Environmental Features of Virginia
Pocahontas No. 3 Preparation Plant", Mining Congress Journal,
April 1973
Blankmeister, W.; Bogenschneider, B.; Kubitaz, K.H.; Leininger, D.;
Angerstein, L; Kohling, R., "Optimised Dewatering Below 10 MM",
German, Australian Coal Conference
Boiko, V.A. Parinskiy, O.P., "Equipment for Dewatering of Coal",
Chapter 5 of "Hydraulic Capability for Underground Mining of Coal",
Katalog-Spravochnik, Moscow, 1965 (Translated by Terraspace)
Bowen, James B. & Guiliani, R.L., "The Integrated Occupational Health
Program of the Erie Mining Comany", American Mining Congress
Convention, Las Vegas, Nevada, October 1974
Burdon, R.G.; Booth, R.W.; Mishra, S.K., "Factors Influencing the
Selection of Processes for the Beneficiation of Fine Coal",
Australia, Australian Coal Conference
Chemical Construction Corporation, "The High Sulfur Combustor - A Study
of Systems for Coal Refuse Processing", New York, New York,
February 1971
Coal Age, "Multi-Stream Coal Cleaning System Promises Help With
Sulfur Problem", January 1976
Coal Age, "U.S. Steel Coal Preparation", Model Mining Issue,
October 1973
Cooper, Donald K., "Coal Preparation - 1974", Mining Congress Journal,
February 1975
Daub, Charles H.f "The Oneida Plant", Mining Congress Journal, July 1974
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
344
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Deurbrouck, A.W., "Washing Fine-Size Coal in a Dense-Medium Cyclone",
U.S. Bureau of Mines Report of Investigations #7892, 1974
Ellison, William; Hedsen, Stanley D.; Kominek, Edward G., "System
Reliability and Environmental Impact of SO Processes", Coal Utili-
zation Symposium-Focus on SO Emission Control, Louisville, Kentucky,
October 1974
Environmental Protection Agency, "Air Pollution Technical Publications
of the Environmental Protection Agency, Research Triangle Park, North
Carolina, July 1974
Gayle, J.G.; Smelley, A.G., "Selectivities of Laboratory Flotation and
Float-Sink Separations of Coal", U.S. Bureau of Mines Report of
Investigations #5691, 1960
Goodridge, Edward R., "Duquesne Light Maximizes Coal Recovery at its
Warwick Plant", Coal Age, November 1974
Gregory, M.H., "Problems Associated with Closing Plant Water Circuits",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Grimm, Bobby M., "Preparation Plant Corrosion Cost", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
Hoffman, L.; Truett, J.B.; Aresco, S.J., "An Interpretive Compilation
of EPA Studies Related to Coal Quality and Cleanability", Mitre
Corporation, May 1974 EPA 65012-74-030
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Provence Coalfield", France, Australian Coal Conference
Irminger, P.F.; Giberti, R.A., "Desulfurization Technology to Meet
the Power Demand", NCA/BCR Coal Conference and Expo II, October 1975
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracity in the Ukraine", Ugol Ukrainy
#2, February 1975 (translated by Terraspace)
Jenkinson, D.C., "Some New Coal Preparation Developments in the United
Kingdom", National Coal Board Bulletin M4-B148
345
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Johakin, J., "Solving the SO Problem—Where We Stand with Application
and Costs", Coal Age, May 1975
Keystone, "Coal Preparation Methods in Use @ Mines", pp. 230-240
Kollodiy, K.K.; Borodulin, V.A.; Nazarov, P.G., "Processing of Coal
Mined by the Hydraulic Method", Ugol #9, 1974 (Translated by
Terraspace)
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Mettalurgical and Petroleum Engineers, Inc., 1968
Lowry, H.H. (Editor), "Chemistry of Coal Utilization", John Wiley &
Sons, Inc.., New York, New York, 1963
Martin, John F., "Quality of Effluents from Coal Refuse Piles", Coal
and the Environment Technical Conference, October 1974
Martinka, Paul D.; Blair, A. Ross, "Western Coal Transportation - A
Challenge", American Mining Congress Convention, October 1974
McNally-Pittsburg Manufacturing Corporation, "Coal Cleaning Plant
Prototype Plant Design Drawings", Department of Health, Education
and Welfare Contract 22-68-59
McNally-Pittsburg Manufacturing Corporation,"Coal Preparation
Manual #572", Extensive Analysis on McNally Pittsburg Coal Cleaning
Technology
McNally-Pittsburg Manufacturing Corporation "A Study of Design and
Cost Analysis of a Prototype Coal Cleaning Plant", Department of
Health,Education and Wealfare Contract PH 22-68-59
Miller, F.; Wilson, E.B., "Coal Dewatering - Some Technical and
Economic Considerations", American Mining Congress Coal Convention,
May 5-8, 1974
National Coal Association, "First Symposium on Mine & Preparation Plant
Refuse Disposal", Coal and the Environment Technical Conference,
October 1974
Norton, Gerry1 Symonds, D.F.; Zimmerman, R.E., "Yield Optimization
in Process Plan Economics", AIME Annual Meeting, New York, New York,
February 1975
Nunenkamp, David C., "Survey of Coal Preparation Techniques for
Hydraulically Mined Coal", Published for Terraspace Inc., July 1976
346
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
Desulfurization", Chicago, Illinois, October 1965
Protopapas, Panayotis, "A Report in Mineral Processing", Department of
Applied Earth Sciences, Stanford University, 1973
Roberts & Schaefer Company, "Manufacturers Information Booklets",
Chicago, Illinois
Roberts & Schaefer Company, "Design & Cost Analysis Study for Proto-
type Coal Cleaning Plant", August 1969
Roberts & Schaefer Company, "Research Program for the Prototype Coal
Cleaning Plant", January 1973
Terchick, A.A.; King, D.T.; Anderson, J.C., "Application and Utili-
zation of the Enviro-Clear Thickener in a U.S. Steel Coal Preparation
Plant", Transactions of the SME, Volume 258, June 1975
U.S. Bureau of Mines, "Methods of Analyzing and Testing Coal and Coke",
Bulletin 638, Office of the Director of Coal Research, 1967
Wahler, William A., "Coal Refuse Regulations, Standards, Criteria and
Guidelines", Coal and the Environment Technical Conference,
October 1974
347
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THIS PAGE INTENTIONALLY LEFT BLANK
348
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12. POTENTIAL POLLUTANTS
12.1 INTRODUCTION . . .
The potential pollutants or materials which will have
a deleterious impact on the land, air, water and animal
life in and around coal preparation plants are becoming
increasingly regulated by the individual states and to
some extent by the Federal Government. It is anticipated
that further Federal levels of control will be promulgated.
It is, therefore, imperative that a basic understanding of
the potential pollutants, i.e., source, be developed and
that ultimately a complete understanding of methods or
methodologies for control of such pollutants be achieved
(see Chapter 13).
The deleterious effects to or the negative environ-
mental interactions of coal preparation as it applies to
the land include concerns of land usage, zoning regulations
and coal waste piles and their stability, i.e., how these
factors relate to site selection for the preparation plant
(including transportation access), raw and clean coal
storage facilities and refuse disposal practices.
The air pollution from coal preparation relates
primarily to particulate emissions including fugitive
dust from transportation, such as haul-roads, and from
bulk handling of coal and coal waste products as well as
particulate emissions from thermal drying processes and
from burning refuse piles. There is also additional air
349
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pollution potential in the form of unacceptable, gaseous
emissions from the thermal drying processes and from
burning waste piles.
The potential water pollution from coal cleaning can
affect both surface and ground water sources. The contami-
nants include water-soluble salts principally originating
from the oxidation of pyrites, acids, iron-aluminum-sulfate
ions, trace elements and suspended solids (coal and
minerals) originating from the process water or added to
it during coal cleaning as well as suspended solids from
the runoff of waste piles and the immediate area of the
plant site.
The direct environmental impacts to the animal life
(including the plant work force) other than air and water
revolve primarily around the noise generated by the
transportation of coal and waste and by the individual
process units within the coal cleaning plant.
12.2 IDENTIFICATION OF POTENTIAL POLLUTANTS
12.2.1 Solid Refuse
A study of the geologic foundation of coal is the
first step in understanding the composition of the solid
refuse from the coal cleaning operation. In addition to
the impurities formed in the coal during its deposition,
mineral impurities were carried by the ground water into
the porous layers of fully developed coal seams. The
mining, crushing and washing processes tend to concentrate
many of these impurities in the refuse or gob.
Coal refuse consists primarily of coal, slate, carbon-
aceous and pyritic shales and clay associated with the coal
seam. During the cleaning and preparation process, these
materials are separated from the coal and are then disposed
as spent or refuse materials. The refuse generated in the
350
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preparation plant consists of material ranging from
colloidal size to 12-inch or large maximum particle size.
Prior to the passage of environmental control legislation,
the fine-grained portion was disposed in nearby streams or
rivers, and the coarser materials on refuse piles. Subse-
quent to the implementation of the environmental legislation,
the fine refuse is often pumped as a slurry to a settling
pond where the suspended solids settle or are filtered from
the water. The coarse refuse, which ranges upward in size
from fine sands, is conveyed to the disposal area by trucks,
scrapers, conveyors or aerial tram.
There are several unique characteristics of coal
refuse material. First and most important from a physical
properties standpoint, is the abnormally low specific
gravity of the fine refuse which averages about 1.5 (see
Table 12-1) as compared with an average soil value of 2.65.
As a result of the low specific gravity value, the result-
ing in-place dry density of the fine material, regardless
Table 12-1
Specific Gravity Results for Fine Coal Refuse
Number of Samples
8
15
4
2
1
Average Specific Gravity
Range of Specific Gravity
1.30 - 1.40
1.41 - 1.60
1.61 - 1.80
1.81 - 2.00
2.01 - 2.20
= 1.53
Source: W. A. Wahler and Associates
of its method of disposal, is also very low, with average
values of 50 to 70 pounds per cubic foot. The low density
of the fine wastes can create two deficiencies:
351
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1) at low density, the material cannot adequately
resist the upward flow of water from an
impoundment and, therefore, if placed in the
foundation area without proper ballasting from
heavier materials, it can create serious problems
of internal erosion (piping), and
2) the low density may result in the inability of
the material to mobilize an adequate effective
stress to resist shearing forces.
The coarse coal refuse, on the other hand, generally
possesses a specific gravity more like that of a natural
soil material. The coarse materials, however, contain
flat, plate-like particles typical of slates and shales,
which undergo rapid weathering to clay after the material
has been deposited on the refuse pile. Also, if dumped
in a loose fashion, the coarse coal refuse will have a
high porosity (volume of voids) and tend to ignite by
spontaneous combustion. The burning of the coarse refuse
causes the material to fuse together, thereby resulting
in a net volume reduction and the possible development of
large voids in the materials during the burning process.
Coal refuse and burned refuse, often called red dog, also
tend to weather faster than most other alluvial or
residual soils.
In an effort to build a model of a typical coarse
coal refuse dump, W. H. Davidson of the USDA Forest Service
conducted a physical and chemical analysis of 79 refuse
piles typical of the major seams mined in each inspection
district in Pennsylvania. In all, 304 samples were
collected. Four samples each were taken from 72 piles,
two from weathered refuse in the 0- to 6-inch layer and
two from unweathered refuse at the 24-inch depth. Seven
piles were too small to warrant taking four samples, so
352
-------
only one surface and one deep sample were taken. Each
sample consisted of a composite of material from two holes
about 10 feet apart, and each weighed about 20 pounds.
Samples were placed in labeled paper bags and air dried.
Physical analysis of the samples consisted of
separating the refuse into four size classes: less than
2 mm (soil size)/ 2 mm to 1/4 inch, 1/4 inch to 2 inches,
and over 2 inches. Each sample was then analyzed, by
standard laboratory methods, for the following chemical
properties: pH, total acidity (meg H+/100 gm), conductance
(mmho/cm), sulfates (ppm SO.) and phosphorus (ppm P).
After physical and chemical analysis, the data were
examined for similarities by coal seam or geographic
region. If there were no such similarities, classifica-
tions were attempted by combinations of physical and
chemical characteristics with pH as the primary factor.
Further classification could be made by size composition
(expressed as percentage of soil-size particles), total
acidity, phosphorus and combinations of these factors.
Evaluation of the data obtained from the laboratory
analyses revealed no distinct correlations of either
physical or chemical characteristics with inspection
district, coal seam being mined or even the depth from
which the sample was collected. Thus, no general classifi-
cation can be made. Summaries of the analyses are shown
in Table 12-2 and 12-3. Data from 268 samples were used
in the summaries as the remaining 36 samples were from
piles containing refuse from two or more different coal
seams. Values of pH 'ranged from a low of 2.0 to a high of
9.4. Values in the very high acid ranges were far more
common than in the slightly acid to alkaline ranges. Only
21 samples (7 percent) were pH 6.1 or above. There were 29
353
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(8 percent) in the range pH 4.1 to 6.0, 140 (47 percent)
in the range pH 3.1 to 4.0 and 114 (38 percent) were pH
3.0 or less. The other chemical characteristics showed
the same wide range of variance.
Table 12-2
Distribution of particle Sizes in Samples of
Underground-Mine Refuse (in percent)
Size
>2"
l/4"-2
Z mm
-1/4"
<2 mm
Number of
sampl es
Samp] e
Average
Median
Highest
Lowest
Average
Median
Highest
Lowest
Average
Median
Highest
Lowest
Average
Median
Highest
Lowest
A
7
4
19
0
36
41
54
21
26
24
43
18
31
30
52
16
10
B
4
1
31
0
30
29
84
4
28
26
58
0
37
37
67
1
88
C
5
0
18
0
25
28
37
9
27
30
37
19
44
43
57
33
8
Seam
C'
5
0
34
0
33
27
65
20
27
27
37
14
35
41
49
11
16
0
4
3
17
0
31
32
61
9
30
29
53
19
35
36
67
9
26
E
5
4
30
0
35
33
72
12
27
26
52
6
33
33
62
0
50
Pittsburgh
4
3
20
0
32
33
59
12
28
28
43
17
37
34
63
16
70
Source: W. H. Davidson, USDA Forest Service
Northeastern Forest Experiment Station
Kingston, Pa.
Based on the research done by Mr. Davidson and others,
it is generally concluded that it is not possible to
develop a definitive personality profile of coal waste
disposal dumps. However, it is possible to generalize
about the overall nature of refuse deposits.
Early refuse deposits were relatively small in volume;
however, as mining rates increased, refuse accumulation
354
-------
rates increased. Although mining and coal processing
technology improved with increasing coal production quan-
tities, refuse disposal technology did not keep abreast,
and as a direct result, coal refuse deposits grew to
enormous size without regard to long-term safety or environ-
environmental consequences.
Table 12-3
Selected chemical characteristics of
samples of underground-mine refuse
Seam
Sample
A
B
C
C'
D
E
Pittsburgh
PH
Average
Median
Highest
Lowest
3.1
2.9
4.1
2.6
3.4
3.2
6.8
2.2
3.0
3.1
3.4
2.4
3.5
3.3
4.4
2.6
Exchangeable acidity (meq H
Average
Median
Highest
Lowest
Average
Median
Highest
Lowest
Average
Median
Highest
Lowest
'
j Average
! Median
Highest
Lowest
Number of
samp] es
8.5
5.8
22.2
2.3
0.87
.75
2.23
.22
1,209
657
3,227
235
0.2
.2
1.0
.0
10
9.8
7.0
113.0
.6
1.88
.61
20.20
.12
3,395
1,087
26,575
62
1.3
.9
15.5
.0
88
6.4
4.4
15.6
3.4
Conductance
1.51
.64
5.06
.27
Sulphates
12,097
4,688
50,438
362
Phosphorus
0.6
.7
1.0
.2
8
5.1
4.2
10.5
2.4
(mmho/cm)
0.32
.21
1.30
.10
(ppm S04)
873
788
2,000
235
(ppm P)
1.0
1.0
2.2
.3
16
3.8
3.6
6.1
3.0
/100 g)
6.4
6.7
14.5
2.4
0.31
.22
1.71
.08
739
520
3,037
37
1.8
.3
16.5
.0
26
3.8
3.4
9.4
2.4
8.0
6.5
39.0
.4
1.61
.86
8.57
.12
4,643
1,050
30,150
62
3.1
1.4
16.5
.0
50
3.6
3.1
7.7
2.4
8.8
9.1
33.4
.3
2.30
2.48
6.75
.12
10.953
6,937
30.150
270
6.7
6.1
21.0
.7
70
Source: W. H. Davidson, ibid
The "calm bank", "slate dump", "refuse dump" or
"waste heap" was, in the earliest mining days, simply the
easiest spot for random dumping of unwanted material.
This "spot" may have been adjacent to the preparation
355
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plant, over the nearest hillside or in the nearby stream
bed. Various methods have been employed to transport
material to the waste dump. Each method was developed to
take advantage of the terrain and to apply to the type and
quantity of refuse being produced. In most cases it is
the characteristics of the refuse that dictate disposal
techniques. Disposal, as well as construction, can be
viewed as consisting of two operations—conveyance and
placement. Coarse refuse is conveyed to the disposal site
in a number of ways, including: hauling in trucks over
access roads, in cars on rails, on aerial tram systems, on
conveyor belts and sometimes combinations of more than one
system. At times, coarse refuse is crushed and conveyed
in a slurry with fine refuse in pipelines. Fine refuse
is almost always conveyed in a slurry through pipelines
to a disposal area, normally an impoundment.
The failure to properly allow for and to accordingly
plan and engineer these waste sites has caused many of them
to become environmental hazards. Disposal practices can
be adverse in a number of ways, including: burning coal
refuse dumps which pollute the air, contaminated or acid
water drainage which will degrade a water course, poor
stability characteristics which present a high degree of
hazard to life and property downslope from the waste
deposit and unsightly waste facilities which cannot be
converted to other uses after mining operations have
terminated (without inordinate expenditures) offer a
serious aesthetic blight. Additionally, these waste
deposits usually support little or no vegetation and,
therefore, contribute heavily to airborne dust.
12.2.2 Mine Site and Waste Dump Drainage
The potential for contamination of water supplies,
both surface and ground water, has been recognized in most
356
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mining areas for a considerable time, and some measures to
control degradation of waters have been initiated. Poten-
tially the most hazardous threat involving water—the
sudden failure of a refuse retaining structure, thus
releasing large quantities of contaminants and/or dump
volume of flood water and sludge—has, to a large degree,
been neglected.
The production of harmful water pollutants from coal
mine sites and/or from coal associated strata has been a
recognizable fact in the United States for over two hundred
and seventy years. In 1689, Gabriel Thomas observed that
the colored water flowing from streams in this country was
similar to that which flowed from the coal mines in Wales.
Water pollutants, such as acid, were being produced before
any known coal mines were operating in this country. The
coal mining industry has contributed to the increase of
pollution by exposing large amounts of sulfide materials
that enable the reaction of water, oxygen and sulfur con-
taining materials to form acid.
Mine drainage includes all types of mine water
associated with coal mining operations. Mine drainage
from coal mine sites may be acid, alkaline or neutral,
depending upon the type of rocks or strata the water passes
through, the distance it travels and the time it remains
in contact with soluble minerals. The drainage may contain
a lot of impurities or only a small amount. A substantial
amount of mine drainage is neutral or slightly alkaline
and contains only minor impurities.
The most difficult type of mine drainage to handle is
acid mine drainage. This type of drainage is formed by
the reaction of air and water with sulfide minerals present
in or associated with the coal bed or refuse pile. By far,
357
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Figure 12-1
Typical Disposal Sites
358
-------
the most common acid-producing sulfide mineral is iron sul-
fide, but other sulfide minerals, i.e., copper, zinc or lead
(Cu-S, ZnS or PbS) may be found associated with the deposits.
According to Ronald D. Hill, the exact mechanism of
acid mine drainage formation is not fully understood, it
is generally believed that pyrite (FeS2) is oxidized by
oxygen (Equation 1) or ferric iron (Equation 5) to produce
ferrous sulfate and sulfuric acid.
(1) 2FeS2 + 2H20 + 702 - 2FeS04 + 2H2S04
(pyrite) (ferrous iron +
sulfuric acid)
Subsequent oxidation of ferrous sulfate produces
ferric sulfate:
(2) 4FeS04 + 2H2S04 + 02 - — 2Fe2(S04)3 + 2H20
The reaction may then proceed to form a ferric
hydroxide or basic ferric sulfate and more acid:
(3) Fe2(S04)3 + 6H20 — - — 2Fe(OH)3 I + 3H2SC>4
(4) Fe2(S04)3 + 2H20 - *~ 2Fe (OH) (804) + H2S04
Pyrite oxidation by ferric iron
(5) 14Fe+++ + FeS2 + 8H20 - —15Fe++ + 2S04= + 16H+
A low pH water is produced (pH 2-4.5). At these pH levels,
the heavy metals such as iron, calcium, magnesium, mangan-
ese, copper and zinc are more soluble and enter into the
solution to further pollute the water.
The mining and subsequent washing of coal is not a
prerequisite to the formation of acid mine drainage;
however, coal mining has greatly contributed to the
generation of acid drainage. The contribution of coal
cleaning to acid mine drainage is tremendous and must not
be overlooked, particularly when it may be difficult to
359
-------
classify mine drainage as occurring from an abandoned
underground coal mine or from an abandoned coal refuse
pile.
Historically, the amount of coal refuse generated
annually in the United States has been increasing at an
ever greater rate than the amount of raw coal mined. This
increase has been continuous since 1930, and is due to two
factors: changing mining methods, and increased emphasis
upon clean fuels. With the development of mechanized
mining techniques and equipment, full seam mining was
introduced. Greater quantities of impurities associated
with the coal seam could be excavated with the coal,
transported to the surface and removed before marketing.
While there have been exceptions where the impurities
(refuse, gob) were treated not only with concern for
operating convenience over the life of the plant, but also
with considerations for eventual abandonment, on the whole,
refuse disposal has been rather casual. The result has
been the development of many large, undesigned and often
poorly constructed coal refuse dumps and impoundments
offering an ideal environment for the formation of an
acidic drainage containing many suspended solids, dissolved
iron and other compounds which may enter the streams and
rivers as runoff or seepage. In addition, the continual
exposure to the elements causes erosion which in turn
offers new material for oxidation which produced more
acid, and the resultant environmental contamination cycle.
A full appreciation of the problems of water pollution
caused by acid mine drainage requires a basic understanding
of occurrences and movement of water in the ground and the
modes of ground water entrance into mining areas as well as
the characteristics of the entire cover, adjacent mining
operations, ad infinitum.
360
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The quality of the water affected by acid mine drainage
is variable, but general criteria for the identification
of streams with major mine drainage influence are given in
Table 12-4. Due to the low pH, the dissolved solids
loading may contain significant quantities of iron,
aluminum and other heavy metals depending on mineralogical
composition of the coal/refuse deposit. The most useful
indicator of acid mine drainage presence and concentration
is sulfate. Calcium sulfate, the most common neutraliza-
tion product, is soluble at concentrations usually
encountered in receiving streams. The other materials in
acid mine drainage tend to precipitate or plate out of
solution and are difficult to analyze reliably as the pH
and alkalinity of the receiving water change. Because
sulfates are usually present in receiving streams in low
concentrations and are found in high concentrations in
acid mine drainage, the presence of sulfate gives an
accurate indication of mine drainage presence.
Table 12-4
CRITERIA FOR DETERMINING ACID MINE DRAINAGE
PH
Acidity
Alkalinity
Alkalinity/Acidity
Fe
S04
Total Suspended Solids
Total Dissolved Solids
Less than 6.0
Greater than 3 mg/1
Normally 0
Less than 1.0
Greater than 0.5 mg/1
Greater than 250 mg/1
Greater than 250 mg/1
Greater than 500 mg/1
(After Herricks and Cairns)
361
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The relationship between acid mine drainage intensity
and stream-flow is important. Mine drainage volume and
discharge intensity have been shown to be seasonally
related. The mine drainage volume is dependent oh rainfall
infiltration to underground areas and refuse piles.
Although pyrite oxidation is not appreciably changed by the
amount of water present, the concentration of pyritic
oxidation end products will vary with volume. Because the
infiltration rate is greater during the winter, the
volume of discharges is normally increased from December
through April. Infiltration decreases during the summer
months; thus, mine discharge volumes also decrease.
The major source of acid is pyritic materials located
above normal water levels. When the mine or pile is
flooded by high base flow (i.e., high infiltration rate)
the pyritic oxidation is limited by oxygen transport
relationships in the water reducing overall AMD concentra-
tions. If flow through the mine or pile has been low for
some time, the oxygen-rich atmosphere allows rapid oxida-
tion of pyrite, and large quantities of oxidation products
may be present on unflooded surfaces. As water flow
increases, these oxidation products are put into solution.
The first flush discharges, caused by high flow, may be
highly concentrated.
Superimposed on this pattern of seasonal changes in
base flow and AMD concentration are several concentration
and stream impact relationships. First, because the first
flush discharges may be more concentrated, the assimilative
capacity of the stream may be overloaded from sludge loads.
Second, the capacity of the receiving stream to assimilate
a given acid mine drainage volume and concentration varies
with stream drainage and is particularly related to the
percentage of base flow represented in the receiving stream,
362
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presence of calcareous rocks and several physical factors
such as temperature.
Temperature and seasonal climatic conditions affect
AMD in other ways. The AMD from underground sources or
buried waste piles during the summer months is usually
poorly oxidized because oxygen is limited in the mine
drainage. The oxidation of this mine drainage in the
receiving stream places.a severe oxygen stress on the
receiving stream. Thus a secondary stress occurs due to
the high oxygen demand of the mine drainage which occurs
when water temperatures are generally high, and dissolved
oxygen is low.
A second seasonally related AMD discharge problem
occurs from surface sources. Pyritic materials on gob
piles are well oxidized. During the winter months the
reduced surface temperature reduces oxidation rates, and
temperatures below freezing prevent runoff from the gob
piles. The initial melt carries the oxidation products
into the receiving stream, but the high assimilative capa-
city of the stream due to the normal high stream discharge
reduces its effect. On the other hand, chemical reactions
on the gob piles are increased during the warm summer
months. Rainfall during this period usually occurs as
high intensity storms which flush unvegetated areas rapidly,
v
The accumulation of pyritic oxidation end products make the
initial runoff highly concentrated, and acid mine drainage
sludges precede the increased stream flow.
An additional problem associated with the water
effluents from the coal cleaning operation and waters
draining from the plant site is the quantity of fine
coal and refuse materials carried in suspension. These
waters are characterized by a heavy concentration of
suspended solids and a deep black color. The black color
of the coal fines imparts a characteristic (black-water)
363
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look to the receiving streams. The suspended solids may
settle to the bottom in quiet pools. If the bottom
organisms upon which the fish live are covered by these
fines, then the coal and refuse fines are detrimental to
the water life by destruction of the food supply. In
addition, the settled solids can restrict the natural
development of water life eggs laid at the bottom of the
stream.
12.2.3 Air Contaminants
Literally any substance not normally present in the
atmosphere, or measured there in greater than normal
concentrations, should be considered an air contaminant.
More practically, however, a substance is not labeled as a
contaminant until its presence and concentration produce
or contribute to the production of some deleterious effect.
The factors that contribute to the creation of an air
pollution problem are both natural and man-made. The
natural factors are primarily meteorological, sometimes
geographical and are generally beyond man's sphere of
control, whereas the man-made factors involve the emission
of air contaminants in quantities sufficient to produce
deleterious effect and are within man's sphere of control.
The natural factors that restrict the normal dilution of
contaminant emissions include: temperature inversions,
which prevent diffusion upwards; very low wind speeds,
which do little to move emitted substances away from their
points of origin; and geographic terrain, which causes the
flow to follow certain patterns and to carry from one area
to another whatever the air contains. The man-made factors
involve the contaminant emissions resulting from some
human activity, e.g., coal preparation.
Coal preparation plants were specifically named as
major sources of air pollution in 40 CFR Part 52,
364
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"Prevention of Significant Air Quality Deterioration",
published as proposed in the Federal Register, July 16,
1973. Substances considered air contaminants in and around
coal preparation plants fall into two general classes
based on their physical state and on their chemical
composition. These are:
1) aerosols (particulate matter) and
2) inorganic gases.
12.2.3.1 Aerosols or Particulate Matter Matter
dispersed into the atmosphere may be organic or inorganic
in composition, and in the liquid or solid physical state.
By definition, they must be particles of very small size
or they will not remain dispersed in the atmosphere. Among
the most common aerosol emissions found from the coal
preparation plant site are coal dust, carbon or soot
particles; metallic oxides and salts; acid droplets; and
silicates and other inorganic dusts.
The non-stack or fugitive emissions from the coal
preparation process occur from operations in which the coal
or its waste products are stored, transferred or reacted
as highlighted in Figure 12-3. The ROM coal is transported
(by truck, conveyor or rail car) to the preparation plant.
The transport and the subsequent transfer to a storage
pile or silo are the first opportunities for fugitive coal
and/or road dust emissions. As noted earlier, if the ROM
coal is stored in an open pile, it may be subject to
wind-blown coal losses. If the pile is dry and the
locale is subject to high and frequent winds and pile
working, these losses can be serious. Additionally, unless
outdoor conveyors and transfer points are enclosed and
appropriately controlled, coal being transferred may be a
source of wind-blown coal dust.
365
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U)
CTl
cn
Raw Coal
Transfer
Stacker
Reclaimer
Operation
Gob Pile
Fires
Screener-Dner
Building Venting
Raw Coal
Transfer
Cleaned Coal
Transfer
Cleaned Coal
Transport
J.J.DAVIS
AS S O C I ATE S
Potential Fugitive
Emission Sources
-------
Within the coal cleaning plant, the initial raw coal
sizing operations, prewetting operations, some dewatering
and mechanical drying operations such as centrifugal
drying and the mechanical transportation of the cleaned
coal and refuse products may be sources of fugitive
emissions. The final transfer of the cleaned coal and
refuse products and the storage of those products is also a
significant source of aerosol emissions, particularly if
the local waste pile should ignite through spontaneous
combustion. The final transfer of the cleaned coal to
railroad cars, barges or trucks and the subsequent transfer
to the user is the last primary opportunity for fugitive
emissions from the coal cleaning operation.
In addition to the fugitive aerosol emissions from the
general preparation plant site, the largest single source
for particulate matter dispersement into the atmosphere
is the thermal coal dryer. The emissions from the thermal
dryers include combustion products from the coal fired
furnace, but these quantities are a small fraction of the
particulates entrained by the flue gases passing through
the fluidized bed of intermediate and fine sized coal.
Emission factors for coal thermal dryers are shown in
Table 12-5. The particulates emitted from the coal
composition unit consist primarily of carbon, silica,
alumina and iron oxides in the fly ash as well as trace
quantities of heavy metals. Table 12-6 shows a typical
analysis of the heavy metals content of particulates
emitted from thermal dryers.
The concern about the trace element content primarily
relates to air pollution, but can extend to coal water
drainage and, to a lesser extent, to process waters asso-
ciated with coal preparation plant operations. Despite
growing interest, only limited data are available on these
367
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Table 12-5
Particulate Emission Factors for Thermal Coal Dryer3
Type of dryer
Fluidized bed
Flash
Multilouvered
Uncontrolled emissions'3
Ib/ton kg/MT
20
16
25
10
8
12.5
Emission factors expressed as units per unit weight
of coal dried.
Typical collection efficiencies are: cyclone
collectors (product recovery), 70 percent; multiple
cyclones (product recovery), 85 percent; water
sprays following cyclones, 95 percent; and wet
scrubber following cyclones, 99 to 99.9 percent.
Source: EPA Publication AP-42, 2nd Edition
trace metals. The analytical difficulties in such
determinations can be formidable and limiting due to the
requirements for evaluation at the part-per-billion level.
The range of concentration, quantity and particle
size of atmospheric pariculate emission is dependent upon
the type of combustion unit in which the coal is burned,
the collection device(s) used to reduce particulate
emission from the thermal dryer stack and the ash and sur-
face moisture content of the coal being burned.
12.2.3.2 Inorganic Gases constitute the second major
group of air contaminants found in and around coal prepara-
tion facilities. The inorganic gases generated include
the oxides of nitrogen, the oxides of sulfur (primarily
802) including sulfuric acid, carbon monoxide and water.
All of the inorganic gases are products of the thermal
drying operation or burning coal refuse piles.
368
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Table 12-6
Trace Metal Analysis of Particulate Emissions from a Coal Dryer
Element
Be
Cd
As
V
Mn
Ni
Sb
Cr
Zn
Cu
" Pb
Se
B
F
Li
Ag
Fe
Na
a
Parts per
Concentration
ppmwa
1
50
100
50
50 to 100
20 to 30
50
30
100
30
30
—
. 10
—
10
1
5000
300
million by weight
Element
K
Ca
Si
Mg
Bi
Co
Ge
Mo
Ti
Te
Zr
Ba
Al
Cl"
S04
Sn
Sr
Concentration
ppmwa
1000 to 2000
3000
1.5%
1000
10
10
30
10
500
100
10
200
1.0%
40 to 118
1040 to 3920
50
100
Source: EPA 450/2-74-021a
A number of compounds must be classified as oxides of
nitrogen, but only two, nitric oxide (NO) and nitrogen
dioxide (N02) are important as air contaminants. The first,
nitric oxide, is formed through the direct combination of
nitrogen and oxygen from the air in the intense heat of any
combustion process. The nitric oxide emitted to the
atmosphere through the flue gases is then able, in the
presence of sunlight, to combine with additional oxygen
to form nitrogen dioxide. Usually the concentrations of
nitric oxide in the combustion effluents constitute 90
369
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percent or more of the total nitrogen oxides. Nonetheless,
since every mole of nitric oxide emitted to the atmosphere
has the potential to produce a mole of nitrogen dioxide,
one may not be considered without the other. In fact,
measurement of their concentrations often provides only a
sum of the two reported as the dioxide.
The primary deleterious effects of the oxides of nitrogen
relate to the toxicity of the dioxide (such as damage to the
lungs), its contribution to photochemical smog and its accom-
panying sharp odor. Nitrogen dioxide in concentrations of
approximately 10 ppm over an 8 hour period can produce lung
injury and edema, and in greater concentrations, e.g., 20 to
30 ppm over 8 hours, can produce fatal lung damage.
The air contaminants classified as oxides of sulfur
consist essentially of only two compounds, sulfur dioxide
(802) and sulfur trioxide (SO^). The source of both
compounds is the combination of atmospheric oxygen with the
sulfur in the coal being combusted for the thermal dryers.
The total emitted quantities of the sulfur oxides is
directly related to the sulfur content of the coal, the
type of combustion unit and the amount of excess air used
during the combustion process.
Normally, sulfur dioxide is emitted in much greater
quantities than sulfur trioxide. Sulfur trioxide is usu-
ally only formed under rather unusual conditions and is in
fact normally a finely divided aerosol rather than a gas.
The primary deleterious effects of the sulfur oxides
relate to their toxicity. Both the dioxide and the
trioxide are capable of producing illness and lung injury
at concentrations as low as 5 to 10 ppm. Further, each can
combine with water contained in the flue gases or from the
atmosphere to form toxic acid aerosols that can corrode
370
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metal surfaces and destroy plant life. Sulfur dioxide by
itself also produces a characteristic type of damage to
vegetation. In concentrations as small as 5 ppm, sulfur
dioxide is an irritant to the eyes and the respiratory
system. Both the dioxides and trioxides of sulfur can
combine with particles of soot and other aerosols to
produce contaminants more toxic than either of the contami-
nants alone. The combination of the dioxides and trioxides
with their acid aerosols have also been found to exert a
synergistic effect of their individual toxicities.
12.2.4 Noise
Noise in coal preaparation plants typically results
from numerous simultaneous noise sources. Although the
noise-producing machinery varies with the plant process and
arrangement, the basic noise-generating mechanisms are the
same for many different machines. The machinery found in
coal cleaning plants may be classified in terms of the
basic noise-producing mechanisms, and noise control may be
approached in relation to these mechanisms. The primary
mechanisms are: impacts, fluid flows and structural vibra-
tions. Impacts of coal on coal or coal on steel dominate
in screens, chutes, hammer mills, hoppers and bins; impacts
of steel on steel are responsible for the noise of car
shakeouts and for the gear noise of crushers. Fluid flow
noise emanates from flowers, fans, vacuum pumps, valves and
air blasts. Structural vibrations contribute to the noise
of screen shaking mechanisms, blowers, gear drives, pumps,
centrifugal dryers, conveyors, feeders and the snubbing
tanks of vacuum pumps.
Tables 12-7 and 12-8 present a rank-ordering of
machinery in terms of need for quieting, taking account of
both the noise levels and the worker exposure. All items
371
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Table 12-7
Rank Ordering of Equipment in Terms of Noise Source
RANK
1
2
3
4
5
6
EQUIPMENT
Car Shakeout
Screens
Picking Tables
Blowers, Dryers,
Air Pumps, Fans,
Crushers, Air
Valves, Feeders,
Flighted Convey-
ors , Chutes
Motors , Gear
Drives , Liquid
Pumps , Hoppers
Belted Convey-
ors, Deister
Tables , Flota-
tion Cells, Water
Falls, Rotary
Pumps , Heavy
Media Vessels,
Cyclones
TYPCIAL SOUND
LEVEL AT WORKER
POSITION dB(A)
110-120
95-105
90- 95
90-105
85- 95
75- 85
TYPCIAL
WORKER PROXIMITY
2 Workers, Full-Time
Predominant In-Plant
Noise Source; Many
Workers, Often Near
Full Time
1 Worker, Full Time
Maintenance and
Operational Support
Workers
Maintenance and
Operational Support
Workers
Maintenance and
Operational Support
Workers
Source: Bolt Beranek and Newman, Inc.
372
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Table 12-8
Typical Major Equipment List in a Large Processing Plant
and Associated Noise Level dB(A)
EQUIPMENT
Heavy Media Cyclones
Crushers
Rotary Breaker
Scalping Screens
(Shaker Drive)
Clean Coal Screens
(Shaker Drive)
Refuse Screens
(Shaker Drive)
Centrifugal Dryers
Disk Filters
Vacuum Pumps
Rootes Blowers
Car Shakeout
Conveyors (belt)
Conveyor Drives
Chutes
Fans
Vibrating Feeders
Tappers or Air Blasts
Flotation Cells
Pumps
NUMBER OF UNITS
18
3
1
2
25
1
10
8
8
4
1
10
10
36
2
4
; 10
8
6
TYPCIAL NOISE
LEVEL dB(A)
80
100
100
100
95
100
95
85
95
95
115
80
95
90
95
90
100
75
85
Source: Bolt Beranek and Newman, Inc.
373
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except those in the last group (group 6) must be quieted
if it is desired to provide a plant noise environment that
is below the 8 hour per day allowable 90 dB(a) level.
Most existing statutes governing industrial community
noise prescribe maximum permissible A-weighted levels of
50 dB(a) for nighttime (10 p.m. to 7 a.m.) and 55 to 65
dB(a) for daytime, as measured at the boundaries of
surrounding residential areas. These values assume that
the noise level fluctuates little with time; more stringent
restrictions may apply for fluctuating noise levels. Since
the noises emanating from coal cleaning plants tend to be
essentially non-fluctuating, one may take 50 dB(a) for
nighttime and 60 dB(a) for daytime operation—as measured
at the community boundary nearest the plant—to be reason-
able criteria.
374
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REFERENCES AND/OR ADDITIONAL READING
Akers, David J., Jr.; & Moss, Edward A.; "Dewatering of Mine Drainage
Sludge — Phase II", Office of Research and Monitoring, EPA
R2-73-169, February 1973
Altomare, Philip M., "The Application of the Tall Stack and Meteor-
ology in Air Quality Control of SO ", Coal Utilization Symposium —
Focus on SO Emission Control, Louisville, Kentucky, October, 1974
AMAX Henderson, "An Experiment in"Ecology", Editorial Alert - 1974,
Mountain Empire Publishing Company
American Public Health Association, American Water Works Association &
Water Pollution Control Federation, "Standard Methods for the
Examination of Water and Wastewater" (13th Ed.), APHA, Washington,
D.C., 1971
Anerson, J.C., "Coal Waste Disposal to Eliminate Tailings Ponds",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Atwood, Genevieve, "The Technical and Economic Feasibility of
Underground Disposal Systems", Coal and Environmental Technical
Conference, October 1974
Atwood, Genevieve, "The Technical and Economic Feasibility of
Underground Disposal Systems", First Symposium on Mine and Prepa-
ration Plant Refuse Disposal, Louisville, Kentucky, October 1974
Barnes, H.L. & Romberger, S.B., "Chemical Aspects of Acid Mine Drainage"
Western Research Application Center, University of Southern
California, #CA-67
Battelle-Columbus, "SO Control: Low-Sulfur Coal Still the Best Way",
Power Engineering, November 1973
Bechtel, Inc., "Coal Slurry Pipeline—An Environmental Answer", San
Francisco, California
Benza, Stephen T. & Lyon, Ann E., "The Use of Lime, Limestone and
Other Carbonate Material in the New Coal Era", NCA/BCR Coal
Conference and Expo II, October 1975
Bisselle, C.A.; Haus, S.A.; Lubore, S. H.; Scholl, M.M.; & Wilcox. S.L.,
"Strategic Environmental Assessment System: Initial Analysis of
Environmental Residuals", The Mitre Corporation, February 1973
375
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Black Sivalls & Bryson, Inc., "Study of Sulfur Recovery from Coal
Refuse", U.S. Government Printing Office, September 1971
Bluck, W.V. & Norton, G., "High Intensity Fine Coal Flotation",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Bioko, V.A. Parinskiy, O.P., "Equipment for Dewatering of Coal",
Chapter 5 of "Hydraulic Capability for Underground Mining of Coal",
Katalog-Spravochnik, Moscow, 1965 (Translated by Terraspace)
Bowen, James B. & Builiani, R.L., "The Integrated Occupational Health
Program of the Erie Mining Company", American Mining Congress
Convention, Las Vegas, Nevada, October 1974
Bureau of Water Quality Management, "Air and Water Quality Regulations"
Busch, Richard A; Baker, Ronald R.; Atkins, Lynn A.f "Physical
Property Data on Coal Waste Embankment Materials", U.S. Bureau of
Mines RI 7964, 1974
Capp, John D. & Gillmore, Donal W., "Fly Ash From Coal Burning Power
Plants" An Aid in Revegitating Coal Mine Refuse and Spoil Banks",
Coal and the Environment Technical Conference, October 1974
Capp, John P.; Gilmore, D.W.; Simpson, David G., "Coal Waste Stabili-
zation by Enhanced Water", American Mining Congress Coal Convention,
Pittsburgh, Pennsylvania, May 1975
Carta, M.; Del Fa. C.; Ciccu, R.; Curreli, L.; Agus, M., "Technical
and Economical Problems Connected with the Dry Cleaning of Raw
Coal and in Particular With Pyrite Removal by Means of Electrical
Separation", Italy, Australian Coal Conference
Carter, R.P.; Wilkey, M.L.; Johnson, D.O.; Kennedy, A.S., "Coal
Blending as a Means to Meet Air Emission Standards", NCA/BCR Coal
Conference and Expo II, October 1975
Casali, J.T., "Heat Drying Sludge from Ponds", American Mining Congress
Coal Convention, May 5-8, 1974
Cassady, Jon M., "Obstacle Course for Permits and Approval", American
Mining Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Cavallaro, J.A.; Deurbrouck, A.W.; Baker, A.P., "Physical Desulfuri-
zation of Coal", Alche Symposium Series, Vol. 70, pp. 114-122
376
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Cavallaro, J.A.; Johnston, M.T.; Deurbrouck, A.W., "Sulfur Reduction
Potential of the Coals of the United States", U.S. Bureau of Mines
RI 8118
Chedgy, David G., "Reduction of Environmental Noise Levels at the
Meadow River No. 1 Preparation Plant", American Mining Congress Coal
Show, Detroit, Michigan, May 1976
Chemical Construction Corporation, "The High Sulfur Combustor - A Study
of Systems for Coal Refuse Processing", New York, New York,
February 1971
Chemical Construction Corporation, "The High Sulfur Combustor—Volume I",
National Technical Information Service, Springfield, Virginia,
Feburary 1971
Chironis, Nicholas P., "Results of a Noise Control Program at a New
Coal Preparation Plant", Coal Age, January 1976
Coal Age, "Multi-Stream Coal Cleaning System Promises Help With
Sulfur Problem", January 1976
Coal Research Bureau, "Underground Coal Mining Methods to Abate
Water Pollution", West Virginia University, 1970
Colorado School of Mines, "Removal of Sulfur from Coal by Teatment
with Hydrogen—Phase I", Research and Development Report #77, Interim
Report No. 1
Cook, L., "Practical.Application of Hydraulic Mining at Tahui Buller
Coalfield", Paper 31, Mining Conference, School of Mines & Metallurgy,
University of Otago, May 1953
Cooper, Donald K., "Choosing Closed Circuits for Coal Preparation
Plants", American Mining Congress Coal Show, Detroit, Michigan,
May 1976
Cooper, Donald K., "Coal Preparation - 1974", Mining Congress Journal,
February 1975
Cuffe, Stanley T., et al. "Emissions from Coal-Fired Power Plants",
National Technical Information Service, Springfield, Virginia, 1967
Culp-Culp, "Advanced Waste Water Treatment", Van Norsten, 1971
377
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Cutler, Stanley, "Emissions from Coal-Fired Power Plants", U.S.
Department of Health, Education and Welfare, 1976
Dahlstron, D.A.; Silverblatt, C.E., "Dewatering of Pipeline Coal",
U.S.A., Australian Coal Conference
Dancy, T.E., "Control of Coke Oven Emissions", AISI Yearbook, p. 181,
1970
Danielson, John A. (Editor), "Air Pollution Engineering Manual (2d Ed.)",
U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina, 1973
D'Appolonia, E., "Engineering Criteria for Coal Waste Disposal", Mining
Congress Journal, October 1973
Day, James M., "Current Status of Proposed Federal Waste Disposal Rules",
Mining Congress Journal, June 1974
Dean, K.C.; Havens, Richard; Glantz, M.W., "Methods and Costs for
Stabilizing Fine-Sized Mineral Wastes", U.S. Bureau of Mines RI 7896
1974
Dean, Karl C.; Havens, Richard, "Methods and Costs for Stabilizing
Tailings Ponds", Mining Congress Journal, December 1973
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II ",
Pennsylvania State University, 1963
Decker, Howard W., Jr.; Hoffman, John N., "Dedusting, Dust Collection
and Coal Surface Treatment (Chapter 3)", Coal Preparation, Volume II,
Pennsylvania State University, 1963.
Department of Environmental Resources, "Solid Waste Management", State
of Pennsylvania
Department of Environmental Resources, "Waste Water Treatment Require-
ments"; "Industrial Wastes"; "Special Water Pollution Regulations";
"Erosion Control", State of Pennsylvania
Department of Environmental Resources, "Water Quality Criteria",
State of Pennsylvania
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
.October 1974
378
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Division of American Society Civil Engineering, "Journal of Sanitary
Engineering:
Dokunin, A.V.; Onika, D.G., "Hydraulic Underground Mining", Translated
for Branch of Bituminous Coal Research, Division of Bituminous Coal,
U.S. Bureau of Mines
Doyle, Frank J.; Bhatt, H.G.; Rapp, J.R., "Analysis of Pollution
Control Costs", Report prepared for Appalachian Regional Commission
and Office of Research and Development of the EPA, EPA 670/2-74-009
February 1974
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Analysis of Pollution Control
Costs", EPA 670/2-74-009
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Chemistry & Classification of
Mine Drainage", EPA 670/2-74-009, February 1974
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "National Ambient Air Quality
Standards", EPA 670/2-74-009, February 1974
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Other Mine Drainage Abatement
Procedures", EPA 670/2-74-009, February 1974
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Refuse Bank & Mine Fires",
EPA 670/2-74-009, February 1974
Dunnigan, A.R.; Dennis, R.A., "Control System for a Very Wide Range
pH Effluent Stream"
Durard, John "Permissible Noise Exposure—Walhealey Tables"
Ellison, Richard D.; Almes, Richard G., "Synopsis of Engineering and
Design Manual for Coal Refuse Embankments", Coal and the Environment
Technical Conference, October 1974
Ellison, William; Heden, Stanley D.; Kominek, Edward G., "System
Reliability and Environmental Impact of SO Processes", Coal Utili-
zation Symposium-Focus on SO Emission Control, Louisville, Kentucky,
October 1974
Engdall, R.B., "A Critical Review of Regulations for the Control of
Sulfur Oxide Emissions", Battelle Columbus Laboratories, APCA
Journal, Vol. 23, #5, May 1973
Environmental Analysis, Inc., "Air Quality in Nassau-Suffolk County,
N.Y.", 1972
379
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Environmental Protection Agency, "Air Pollution Emission Factos",
EPA Publications AP-42, April 1973
Environmental Protection Agency, "Air Pollution Technical Publications
of the Environmental Protection Agency, Research Triangle Park, North
Carolina, July 1974
Environmental Protection Agency, "Background Information for Standards
of Performance: Coal Preparation Plants (Volume I: Proposed
Standards)", Emission Standards & Engineering Division, EPA, Research,
Triangle Park, North Carolina, October 1974
Environmental Protection Agency, "Background Information for Standards
of Performance: Coal Preparation Plants (Volume II: Test Data
Summary)", EPA Research Triangle Park, North Carolina, October 1974
Environmental Protection Agency, "Environmental Impact Assessment
Guidelines for Selected New Source Industries"
Environmental Protection Agency, "Municipal Sewage Treatment Standards"
Fair, Geyer, and Okun, "Water and Waste Water Engineering", Vol. 2,
Wiley and Sons, 1968
Fairhurst, Charles, "European Practice in Underground Stowing of Waste
from Active Coal Mines", First Symposium on Mine and Preparation
Plant Refuse Disposal, Louisville, Kentucky, October 1974
Falkie, Thomas W., "Overview of Underground Refuse Disposal", First
Symposium on Mine and Preparation Plant Refuse Disposal, Louisville,
Kentucky, October 1974
Falkie, Thomas W., "Overview of Underground Refuse Disposal", Coal and
the Environment Technical Conference, October 1975
Federal Register, "Mineral Resources - Rules and Regulations", Title
30, Chapter 1, Part 77
Federal Register, "Standards of Performance for New Stationary
Sources (Coal Preparation Plants)1, Volume 39, #207, Part II,
EPA, October 24, 1974
Foreman, William E., "Impact of Higher Ecological Costs and Benefits
on Surface Mining", American Mining Congress Coal Show, Detroit,
Michigan, May 1976
380
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Gayle, J.B.; Eddy, W.H., "Effects of Selected Operating Variables on
Continuous-Cell Flotation of Coal: A Lab Study", U.S. Bureau of
Mines Report of Investigations #5989
Geer, M.R.; Jacobsen, P.S.; Sokasi, M., "Dewatering Coal Flotation
Tailing by the Admixture of Crushed Washery Refuse", U.S. Bureau of
Mines Report of Investigations #7110
Gospodarka, Bornictwa, "Possibilities of Mechanical Preparation Under-
ground", 1956 No. 4
Gregory, M.J., "Problems Associated with Closing Plant Water Circuits",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Greenwald, Edward H., Jr., "A Landscape Architect Looks at Site
Planning and Surface Development of Coal Mining", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
Grim, E.G.; Hill, R.D., "Environmental Protection in Surface Mining
Of Coal", NERC, Cincinnati, Ohio, October 1974, EPA 670/2-74-093
Gvozdek, G.; Macura, L., "Hydraulic Mining in Some Deep Pits in
Czechoslovakia", Translated by National Coal Board (A 1683), Uhli
#12, December 1958
Hall, A.W.; Martin, J.W.; Stewart, R.F.; Poston, A.M., "Precision
Tests of Neutron Sulfur Meter in Coal Preparation Plants", U.S.
Bureau of Mines Report of Investigations #8038, 1975
Hand, John W., "Drying of Western Coal",Mining Congress Journal,
May 1976
Haskins, J. William, "The Economical Advantages of Drying Coal Fines
Using Indirect Heat Exchanging", NCA/BCR Coal Conference and Expo
II, October 1975
Henderson, G.S.; Andren, A.W.; Harris, W.F.; Reichle, D.E.; Shugart,
H.H.; Van Hook, R.I., "Environmental Assessment of SO and Trace
Element Emissions from Coal Utilization", Coal Utilization Symposium-
Focus on SO Emission Control, Louisville, Kentucky, October 1974
Henderson, James, "Environmental Overkill the Natural Resource Impact",
American Mining Congress Convention, October 1974
381
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Hill, Ronal D., "Water Pollution From Coal Mines", Water Pollution
Control Association of Pennsylvania, 45th Annual Conference, 1973
Hoffman, L.;;Truett, J.B.; Aresco, S.J., : An Interpretative Compilation
of EPA Studies Related to Coal Quality & Cleanability", Mitre
Corporation, May 1974 EPA 65012-74-030
Hollinden, Gerald A.; Elder, Henry W., "Worldwide Review of Major
Sulfur Dioxide Removal Processes Applicable to Coal-Fired Utility
Boilers", Coal Utilization Symposium-Focus on SO Emission Control,
Louisville, Kentucky, October 1974
Houle, D.L., "The Effect of Process Design on pH & plon Control",
Eighteenth ISA-AID Symposium, May 3, 1972
Hulett, L.D.; Carter, J.A.; Cook, K.D.; Emery, J.F.; Klein, D.H.;
Lyon, W.S.; Nyssen, G.A.; Fulkerson, W.; Bolton, N.E., "Trace
Element Measurements at the Coal-Fired Allen Steam Plant—Particle
Characterization", COal Utilization Symposium-Focus on SO Emission
Control, Louisville, Kentucky 1974
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Provence Coalfield", France, Australian Coal Conference
Irminger, P.F.; Giberti, R.A., "Desulfurization Technology to Meet
the Power Demand", NCA/BCR Coal Conference and Expo II, October 1975
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracity in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Jimeson, R.M.; Spindt, R.S., "Pollution Control and Energy Needs",
Advances in Chemistry Series, American Chemical Society, Washington,
D.C., 1973
Johakin, J., "Solving the S0» Problem—Where We Stand with Application
and Costs", Coal Age, May 1975
Journal of the Air Pollution Control Association, "Panel Calls Bene-
ficiation-FGD Combination 'Most Economical, Best All-Around Choice"',
November, 1975
Journal of American Water Works Association
Joy Manufacturing Company, "Basic Handbook of Air Pollution Control
Equipment", Western Participation Division, 1975
382
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Kalb, G. William, "The Attainment of Particulate Emission Standards
at Fluidized-Bed Termal Coal Dryers", American Mining Congress
Coal Show, Detroit, Michigan, May 1976
Kalika, Peter W.; Bartlett, Paul T.; Kenson, Robert E.; Yocum, John E.,
"Measurement of Fugitive Emissions", 68th Annual APCA Meeting,
Boston, Massachusetts, June 1975
Kenson, R.E.; Kalika, P.W.; Yocom, J.E., "Fugitive Emissions from
Coal", NCA/BCR Coal Convention and Expo II, October 1975
Kent, James A. (Editor), "Riegel's Handbook of Industrial Chemistry
(7th Ed.)", Van Nostrand Reinhild Publishing Company, New York, 1974
Kilgore, James D., "Physical and Chemical Coal Cleaning for Pollution
Control", Industrial Environmental Research Laboratory, Environmental
Protection Agency, Research Triangle Part, North Carolina
Kodentsov, A.A.; Kurkin, V.F.; Krasnoyarskiy, L.S.; Papkov, M.N.,
"Dewatering of Coal and Rock, Clarification of Waste Water During
Driving by Hydromechanization", Ugol Ukrainy #11 (Translated by
Terraspace)
Krebs Engineers, "Brochure and Letter - June 1975"
LaMantia, Charles R.; Raben, Irwin A., "Some Alternatives for SO
Control", Coal Utilization Symposium-Focus on SO Emission Control,
Louisville, Kentucky, October 1974
Lamonica, J.A., "Noise Levels in Cleaning Plants", Mining Congress
Journal, July 1972
Lawrence, William F.; Cockrell, Charles F.; Muter, Richard, "Power
Plant Emissions Control", Mining Congress Journal, April 1972
Leavitt, Jack M.; Leckenby, Henry F.; Blackwell, John P.; Montgomery,
Thomas L., "Cost Analysis for Development and Implementation of a
Meteorologically Scheduled SO Emission Limitation Program for Use
by Power Plants in Meeting Ambient Air Quality S0_ Standards",
TVA Air Quality Branch, Marcel Dekker, Inc., 1974
Leonare, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Leven, P., "Pumping: A Good Way to Dispose of Coal Plant Refuse",
Coal Mining and Processing, June 1966
383
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Lewis, Clifford J., "Development of a Rotating Stack Gas Scrubber",
NCA/BCR Coal Conference and Expo II, October 1975
Lombardo, J.L., "State-of-the-Art—Acid Mine Drainage Control",
American Mining Congress Mining Convention/Environmental Show,
Denver, Colorado, September 1973
Lowman, Stephen G., "Westmoreland Coal's Bullitt Plant Upgrades Steam
COal Quality", Coal Age, 1973
Lownie H.W. et al., "A Systems Analysis Study of the Integrated Iron
and Steel Industry", EPA Project PH-22-68-65 Report
Lowry, H.H. (Editor), "Chemistry of Coal Utilization", John Wiley &
Sons, Inc., New York, New York, 1963
Lovell, Harold L., "Sulfur Reduction Technologies in Coals by Mechani-
cal Beneficiation (3d Draft)", Commerce Technical Advisory Board
Panel on SO Control Technologies, March 1975
Luckie, Peter T.; Draeger, Ernie A., "The Very Special Considerations
Involved in Thermal Drying of Western Region Coals", Coal Age,
January 1976
Magee, E.M. et al., "Evaluation of Pollution Control in Fossil Fuel
Conversion Processes; Gassification; Sectional: Kopoers-Totzek
Process", EPA Project 69-02-0629
Magee; Hall; Varga, "Potential Pollutants In Fossil Fuels", Environ-
mental Protection Technology Series, ESSO Research & Engineering
Company, June 1973
Magnuson, Malcolm 0.; Baker, Eugene C., "State-of-the-Art in
Extinguishing Refuse Pile Fires", Coal and the Environment Technical
Conference, October 1974
Maneval, David R., "Assessment of Latest Technology in Coal Refuse
Pile Fire Extinguishment", American Mining Congress Coal Show,
Detroit, Michigan, May 1976
Manzual, David R.; Lemezis, Sylvester, "Multistage Flash Evaporation
Systems for the Purification of Acid Mine Drainage", SME/AIME
Translations, Vol. 252
Margolf, Charles W., "Public Information—Industrial Involvement",
American Mining Congress Coal Show, Detroit, Michigan, May 1976
384
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Markley, R.W.; Cavallaro, J.A., "Efficiency in Cleaning Fine Coal by
Froth Flotation—A Cell by Cell Pilot Plant Evaluation", Mining
Congress Journal, June 1974
Martin, John F., "Quality of Effluents from Coal Refuse Piles", Coal
and the Environment Technical Conference, October 1974
Mathur, S.P., "Hydraulic Mining of Coal", Journal of Mines, Metals and
Fuels, May 1972
McCormack, Donald E., "Soil Reconstruction: Selecting Materials for
Surface Placement in Surface-Mine Reclamation", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
McGauey, "Engineering Management of Water Quality", McGraw-Hill, 1968
McNally-Pittsburg Manufacturing Corporation, "Coal Preparation
Manual #572", Extensive Analysis on McNally Pittsburg Coal Cleaning
Technology
McNally-Pittsburg Manufacturing Corporation, "A Study of Design and
Cost Analysis of a Prototype Coal Cleaning Plant", Department of
Health, Education and Welfare Contract PH 22-68-59
Mengelers, J.; Absil, J.H., "Cleaning Coal to Zero in Heavy Medium
Cyclones", Coal Mining and Processing, May 1976
Metcalf & Eddy Inc., "Waste Water Engineering, Collection-Treatment-
Disposal", McGraw-Hill
Meyers, Sheldon, "The Development of Coal Resources and the Environ-
mental Impact Statement", Coal Utilization Symposium-Focus on SO
Emission Control, Louisville, Kentucky, October 1974
Mill, Ronald, "Control & Prevention of Mine Drainage", Battelle
Conference 72, November 1972
Miller, David W., "Toxic Standards for Water Pollution", American
Mining Congress Convention, October 1974
Miller, F.; Wilson, E.B., "Coal Dewatering - Some Technical and
Economic Considerations", American Mining Congress Coal Convention,
May 5-8, 1974
Miller, R.E.; Agarwal, J.G.; Petrovic, L.J., "Economic & Technical
Considerations in the Use of Coal as Clean Fuel", American Mining
Congress Convention, May 6-9, 1973
385
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Montgomery, T.L.; Frey, J.W., "Tall Stacks and Intermittent Control
of SO Emissions TVA Experience and Plans", American Mining Congress
Convention, October 1974
Morris, George J., "Reclaiming Coal from Refusfe Ponds", American Mining
Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Moss, E.Ai; Akens, D.J., Jr., "Dewatering of Mine Drainage Sludge",
EPA R2-73-169, February 1973
Moulton, Lyle K.; Anderson, David A.; Hussain, S.M.; Seals, Roger K.,
"Coal Mine Refuse: An Engineering Manual", Coal and the Environment
Technical Conference, October 1974
Nalapko, I.A.; Shevchenko, I.A.; Manza, P.I., "Industrial Tests of a
Plant Unit for the Extinction and Transportation of Slag and Ash"
Nalco Chemical Company, "Brochure and Letter - 1975"
National Coal Association, "National Ambient Air Quality Standards—
Environmental Protection Agency"
National Coal Association, "Coal Utilization Symposium—Focus on SO
Emission Control", Coal and the Environment Technical Conference
October 1974
National Coal Association, "First Symposium on Mine & Preparation Plant
Refuse Disposal", Coal and the Environment Technical Conference,
October 1974
National Coal Association, "Second Symposium on Coal Utilization",
NCA/BCR Coal Conference and Expo II, October 1975
National Coal Board, "Exploratory Trails in Hydraulic Mining at
Trelewis Drift Mine", September 1961
National Coal Board, "Hydraulic Transport of Coal at Woodend Colliery",
September 1961
Nunenkamp, David C., "Survey of Coal Preparation Techniques for
Hydraulically Mined Coal", Published for Terraspace Inc., July 1976
O'Brien, Brice, "Environmental Protection", Mining Congress Journal,
February 1974
386
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
O'Brien, Ellis J.; Walker, Joseph L., "Environmental and Processing
Innovations—Bullitt Preparation Plant", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania, May 1973
Ottmers, Delbert M.; Phillips, James L.; Sipes, Teresa G., "Factors
Affecting the Application of Flue Gas Desulfurization Systems to
Gas- and Oil-Fired Power Plants Being Converted to Coal-Fired Units",
NCA/BCR Coal Conference and Expo II, October 1975
Padgett, Joseph, "Sulfates—Recent Findings and Policy Implications",
NCA/BCR Coal Conference and Expo II, October 1975
Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
Desulfurization", Chicago, Illinois, October 1965
Peluso, Robert G., "A Federal View of the Coal Waste Disposal Problem",
Mining Congress Journal, January 1974
Peterson, Gerald, "Noise Control in Coal Preparation Plants", Mining
Congress Journal, January 1974
Poland, "Beneficiation of Coal Fines by Selective Flocculation",
Australian Coal Conference
Pollution Engineering Magazine, "Applying Air Pollution Control
Equipment", Environmental Handbook Series
Pollution Engineering Magazine, "Industrial Solid Waste Disposal",
Environmental Handbook Series
Pritchard, David T., "Closed Circuit Preparation Plants and Silt Ponds",
Mining Congress Journal, November 1974
Quig, Robert H., "Chemico Experience for SO Emission Control on Coal-
Fired Boilers", Coal Utilization Symposium—Focus on SO Emission
Control, Louisville, Kentucky, October 1974
Richardson, James.K., "Improving the Public Imaqe of the Mining
Industry", American Mining Congress Convention, October 1974
Roberts & Schaefer Company, "Research Program for the Prototype Coal
Cleaning Plant", January 1973
Rubin, E.S.; MacMichael, F.C., "Impact of Regulations on Coal Conversion
Plants", Environmental Science & Technology, 9, 112, 1975
387
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Sage, W.L., "Combustion Tests on a Specially Processed Low-Ash, Low-
Sulfur Coal", National Technical Information Service, Springfield,
Virginia, 1964
Sableski, Joseph J., Jr.; Sedman, Charles B.; Jones, Larry G.,
"Development of Standards of Performance for New Coal Preparation
Plants", Mining Congress Journal, October 1972
Schaeffer, Stratton C.; Jones, John W., "Coal Preparation vs. Stack Gas
Scrubbing to Meet SO. Emission Regulations", NCA/BCR Coal Conference
and Expo II, October 1975
Scott, R.B.; Hill, R.D.; Wilmoth, R.C., "Cost of Reclamation & Mine
Drainage Abatement, Elkins Demonstration Project", Federal Water
Quality Administration Publication #14010
Seibel, Richard J., "Dust Control at a Transfer Point Using Foam and
Water Sprays", U.S. Bureau of Mines Respirable Dust Program Technical
Progress Report, May 1976
Sittig, Marshall, "Environmental Sources and Emissions Handbook", Noyes
Data Corporation, Park Ridge, New Jersey, 1975
Soderberg, H.E., "Environmental Energy & Economic Considerations in
Particulate Control", American Mining Congress Coal Convention,
May 5-8, 1974
Sorrell, Shawn T., "Establishing Vegetation on Acidic Coal Refuse
Materials Without Use of a Topsoil Cover", Coal and the Environment
Technical Conference, October 1974
Stanin, S. Anthony, "Influence of Coal Waste Disposal Regulations",
American Mining Congress Coal Show, Detroit, Michigan, May 1976
Stefanko, Robert; Ramani, R.V.; Chopra, Ish Kumar, "The Influence of
Mining Techniques on Size Consist and Washability Characteristics
of Coal", National Technical Information Service, Springfield,
Virginia, August 1973
Stoev, St.; Krasteva, K., "Coal Preparation by Reverse Stratification",
Bulgaria, Australian Coal Conference
Terchick, A.A.; King, D.T.; Anderson, J.C./'Application and Utili-
zation of the Enviro-Clear Thickener in a U.S. Steel Coal Preparation
Plant", Transactions of the SME, Volume 258, June 1975
388
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Tempos, E., "Detailed Investigation of Pyrites Distribution, Taking
Account of the Petrographic Components of Coal, with a View to
Reducing the Pyrites Content in Coking Coal", Hungary, Australian
Coal Conference
Tyrea, P.O.; Anderson, M.M., "Pilot Studies in Wet Dust Control",
Mining Congress Journal, September 1973
Ungar, Fax, Patterson, Fox, "Coal Cleaning Plant Noise and Its
Control", Bolt, Beranek & Newman, Inc., U.S. Bureau of Mines
Contract No. H0133027
U.S. Bureau of Mines, "Clean Energy from Coal Technology", Overview of
Coal/Energy Usage, U.S. Government Printing Office, 1974
U.S. Bureau of Mines, "Coal—Bituminous and Lignite in 1973", Division
of Fossil Fuels, U.S. Department of Interior Mineral Industry
Surveys, January 1975
U.S. Bureau of Mines, "Implications of the Water Pollution Control
Act of 1972 for the Mineral Resource Industry: A Survey", Inter-
disciplinary Research Task Force Committee, 1975
Wahler, William A., "Coal Refuse Regulations, Standards, Criteria and
Guidelines", Coal and the Environment Technical Conference,
October 1974
Warnke, W.E., "Latest Progress in Sulfur, Moisture and Ash Reduction
Coal Preparation Technology", American Mining Congress Coal
Convention, Detroit, Michigan, May 1976
Yancey, J.F.; Geer, M.R., "Behavior of Clays Associated with Low-Rank
Coals in Coal-Cleaning Processes", U.S. Bureau of Mines Report of
Investigations #5961
Yenovsky, A.Z.; Remesnilsov, I.D., "Thermomagnetic Method of Concen-
trating and Desulfurizing Coal?
Yusa, M.; Syzuki, H.; Tanaka, S.; Igarashi, C., "Slude Treatment Using
a New Dehydrator", Japan, Australian Coal Conference
389
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13. CONTROL OF POTENTIAL POLLUTANTS
13.1 INTRODUCTION
Each class of pollutant (as identified in Chapter 12,
Potential Pollutants) may include many different compounds,
emanate from several different site sources and contribute
in varying degrees to the overall pollution problem. The
control and/or disposal of each class of pollutants is
equally interrelated even to the point that one control
technique may in itself serve as a primary source for some
other form of pollution.
The largest single source of potential pollutants
from the coal preparation process is the solid refuse.
With the possible exceptions of airborne coal dust and the
particulate and gaseous emissions from the thermal drying
process, and of course noise, solid coal refuse is the
principal source of all pollution emanating from a coal
preparation site. Accordingly, this chapter is broken down
into three general areas:
Refuse disposal and pollution control technology,
Air pollution control and
Noise control. \
13.2 REFUSE DISPOSAL AND POLLUTION CONTROL TECHNOLOGY
The amount of coal refuse generated annually in the
United States has been increasing at an even greater rate
391
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than the amount of raw coal mined. This increase has been
continuous since 1930, and is due to two factors: changing
mining methods and increased emphasis upon clean fuels.
As stated previously in this manual, prior to the
early 1920's, when the mechanization of underground mining
began, only the thicker and more productive seams were
developed; and the coal was mined, picked and loaded under-
ground by hand. During this hand loading process, coal
and refuse were usually separated underground and the
reject materials were permanently stored in worked out
portions of the mine. As a result, with few exceptions,
only marketable coal was transported to the surface.
With the development of mechanized mining techniques
and equipment, full seam mining was introduced. Greater
quantities of impurities associated with the coal seam
were excavated with the coal, transported to the surface
and removed from the coal before marketing. Since this
material has no immediate use, it is usually disposed of
as economically as possible, and in such a manner that the
disposal does not interfere with the overall mining
operations.
The quantity of coal refuse generated in 1969 exceeded
100 million tons for the first time. Estimates are that by
1980 the reject ratio may reach as high as 40% of the total
coal mined; i.e., the total annual amount of coal waste
generated will be in excess of 200 million tons. This
is a conservative estimate, based on a reject ratio
of 40% of the total production of 500 million tons.
However, the dynamics of the production estimates are
very volatile due to the distorted energy situation in
the 1970's, and as noted earlier, current estimates are
that coal production will reach one billion tons per year
shortly before 1985. Such production could mean that the
392
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amount of coal refuse would be as much as 400 million tons
per year.
There are basically three types of refuse material
involved in the disposal process: mine development refuse,
coarse preparation plant refuse and fine preparation plant
refuse. The mine development refuse contributes a rela-
tively minor amount of the total disposal volume but is
significant because of the difference in the materials and
characteristics. Coarse refuse considered herein is a
product of the preparation plant during the cleaning or
benefication of the run-of-mine coal. Coarse refuse is
generally removed by mechanical screening, although hand
picking, heavy medium processes and cyclones are also
utilized for the separating operation. The actual size of
the coarse refuse will vary with the preparation plant
process, but is generally larger than \ inch. Some coal
operations with large amounts of shale partings included in
the coal seam will have coarse refuse in varying amounts
in the +4 inch range.
The term "washing the coal" generally refers to a
heavy medium separation plant, where a differential speci-
fic gravity separation is achieved based upon the creation
of an artificially high specific gravity through the use
of a dense medium. Ground magnetite or sand usually serves
as the heavy medium material. The crushed coal is intro-
duced into a heavy media vessel and the specific gravity of
the contained slurry is controlled to allow the lighter
coal to float to the surface of the vessel. The refuse
fractions (usually the shale and sandstone) are heavier
than the contained coal and settle to the bottom of the
vessel where a mechanical arrangement allows its removal
for reporting to the coarse refuse handling system. Since
the heavy media material is a high cost item, both the
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coarse refuse fractions and the clean coal fractions are
rinsed to remove the finely ground particles adhering to
them. The heavy media material is then removed from the
wash water (using magnetic separation devices in the case
of magnetite) for recycling to the cleaning circuit.
As indicated, the fine refuse is developed at various
points in the coal cleaning process depending on the bene-
fication method utilized. For example, the wash water
from the heavy media recovery system contains fine
particles of coal, silica, shale and other materials and
must be clarified before the water is returned to the plant
process reservoir or released from the plant.
The primary generators of fine coal refuse are:
wet screen processes,
dense media washing systems,
fine coal circuit, i.e., froth flotation and
dewatering systems.
Coarse refuse material is transported by a variety of
materials handling systems, singly and in combination with
others. A listing of the systems would include:
aerial tram,
conveyors, both belt and metal pan,
trucks, both end and bottom dump,
side dump mine cars,
scrappers and
bulldozers.
As with mine development refuse, the majority of operators
in the past have transported and placed coarse refuse under
controlled conditions. Little or no attention was given to
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effective compaction or other inplace density control
methods. Water content depended upon that which came from
the plant, along with additions or deletions from ;the dump
surface in conjunction with current weather conditions.
When controlled placement of coarse refuse is in
effect, the materials handling system might include modifi-
cations such as intentionally routing the trucks to all
areas of the dump in order to achieve some surface
compaction, or the utilization of conventional compactors
and rollers. When this is done, however, Construction
control techniques predominate over the density or related
technical control procedures, resulting in an improved but
not necessarily quality controlled structure.
The placement of fine coal refuse has almost exclu-
sively been through hydraulic methods, that is, a slurry
pumped from the preparation plant to a settling pound.
When the settlement pound is the final disposal site for
the fine refuse, control of the placement consists of
varying the location of the discharge of the pipeline since
the coarser particles will settle closer to the discharge
point and the fine particles will settle further away
where the ponding of water is occurring. The effect of
the point of discharge, with the result in size segregation,
can be of significant importance to the stability of an
impoundment. In recent years, incised ponds adjacent to
the preparation plant have been utilized for plant water
clarification, particularly where process equipment such
as thickeners can perform the primary solids removal work.
These ponds are usually of smaller volume than the
conventional refuse embankment impoundments, and must be
cleaned periodically of the settled solids. This method
requires an excavator, either a drag line or a front end
loader, to load the settled materials onto trucks for
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haulage to the final disposal site. The treatment or
utilization of the fine materials at the dump or embankment
depends upon the method of construction in use at the site.
A disposal site is a geographical location of a past
or present refuse product unit, or units, such as mine or
plant, along with the associated refuse disposal deposits.
A disposal area is part of a site and is that general area
or plot of land which is used for long term storage or
disposal and consists of a dump, or impoundment, or a
combination of dumps and impoundments. The basic differ-
ence between a dump and an impoundment is that, while both
are long term accumulations of mine or plant refuse
materials on or in the earth, a dump is not capable of
impounding liquids and an impoundment is capable of
impounding liquids. An impoundment includes three elements:
the retaining elements such as the embankment, a depres-
sion, etc., and the element of retention capability created
by storage space available to retain liquids' (unused
storage capacity). A disposal site may have more than one
disposal area.
Until recently, coal refuse disposal in the United
States has not been the object of appreciable industry,
government or private interest over the years. The results
of the literature search for this work has indicated the
paucity of materials that exist of the subject. The
textbook and industry reference manuals, while exceedingly
specific on other aspects of the coal preparation disci-
plines, are either lacking completely or woefully deficient
in their coverage and treatment of the refuse disposal
problem. In the early 1950's when most Appalachian states
began to enact and enforce stream pollution control
legislation, the coal preparation plants were faced with
finding an economical method of complying with the new
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laws. Previous to this time, the majority of the plants
had disposed of their coarse refuse on dumps generally
referred to as slate dumps. The plant water was usually
allowed to enter the streams with a minimum of clarifica-
tion. In attempting to find the least expensive way to
clarify the plant waters and sludge which oftentimes
previously had gone directly into the nearest stream, the
coal industry adopted the practice of using coarse mine
refuse to construct impoundments in which water clarifica-
tion could be accomplished. Although the coarse fractions
of the fine refuse were removed by the sedimentation in
the ponds, along with some of the other finer fractions,
the finest material was removed by the process of
filtration as the water seeped through the coarse slate
dump dams. Since the basic objectives of the water
clarifications system thus developed was to filter the
plant water by passing it through their dams, little or
no attempt was made to control the flow of water over or
around the retaining structure. The coarse refuse dumps
which were not useful directly as impoundment embankments
were often converted into filtration structures and were
allowed to continue to grow in size as coal refuse
accumulated.
When the coal refuse dump on the Middle Fork of
Buffalo Creek failed, the coal industry, with assist from
the concerned government and citizens groups, had to take
stock of its solid refuse disposal and water clarification
problems. In the years between February 1972 and February
1975, it is highly probable that more stability investiga-
tion of coal refuse dumps and impoundments were conducted
by engineering personnel than in the entire previous
history of the American coal industry.
The probability of the refuse deposit failures and
the magnitude of the consequences of such failures have
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increased dramatically in recent years as a result of
several factors, the most important of which are:
changing practices in waste water disposal,
finer materials resulting from changing mining
and coal preparation practices,
larger and higher disposal embankments,
more rapid refuse material accumulation resulting
from processing coal from several mines in a
single preparation plant,
more rapid refuse material accumulation resulting
from accelerated mining rates,
degradation of refuse materials due to chemical
alteration, mechanical breakdown and weathering
processes, and
increased habitation of immediately hazardous or
potentially hazardous areas resulting from more
intensive domestic utilization in mine areas,
as well as the increase of mining operations in
inhabited areas.
13.2.1 Refuse Disposal Versus Constructed Embankments
Disposal practices can be environmentally adverse in a
number of ways, including burning coal refuse dumps which
pollute the air, contaminated or acid water drainage which
will degrade a water course, poor stability characteristics
which present a hazard to life and property downslope from
the waste deposit and unsightly waste facilities which
cannot be converted to other uses after mining operations
have terminated, without inordinate expenditure.
The potential for contamination for water supplies,
both surface and ground water, has been recognized in most
mining areas for a considerable time, and some measures
to control degradation of waters are widespread. But the
potentially most hazardous threat involving water—the
sudden failure of a refuse retaining structure, releasing
398
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large quantities of contaminants or a flood of water and
sludge—has to a large degree been neglected.
As a direct result of these factors, disposal of coal
refuse products is now taking a new meaning due to federal
and state safety and environmental regulations. In order
to assure safety and environmentally suitable disposal of
refuse, the dumps and impoundments will have to involve
careful planning, design and- construction as well as
dumping. Where material is deposited on a steep hillside
all of the material to be disposed of will have to be
placed in such a manner as to be stable; the entire deposit
will have to be designed and constructed so that all of
the material placed is stable. Where a long and wide
valley is available for disposal use, it may be possible
to properly construct a relatively small retaining struc-
ture, of carefully placed and compacted refuse material
which will then retain large amounts of material dumped
behind it. Thus, what would usually be a dam if water
were stored behind it can become a retaining structure
where dry material is stored. If site conditions permit
and the project is properly planned, the more expensive
construction can be limited to a small part of the total
disposal effort and the majority of the material can be
dumped with few, if any, stability or environmental
problems.
Dumping is a term that means disposal with little
effort being expended after waste material is removed from
its conveyance, other than perhaps spreading to best
utilize the space reserved for its disposal and to
facilitate transport and dumping of subsequent loads.
Construction, on the other hand, means careful placement,
compaction and material selection so as to develop a
structurally stable unit—stable unto itself or stable as
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a retaining structure to retain or support other material
deposited behind it.
In addition to being required by law, other incentives
for developing properly constructed refuse disposal
facilities exist. Technology exists today from the soil
mechanics and engineering geology fields, as applied in
earth dam design and construction, to properly develop
safe and suitable refuse deposits. This technology only
needs to be applied to mine refuse disposal to construct
environmentally acceptable refuse deposits with minimal
hazards. In addition, considerations such as improved
land use (including upgrading in some cases) may provide
counterbalancing assets which might offset some of the
additional development costs by reducing the potential
liability which would directly reduce insurance costs and
eliminate the possibility of lawsuits while at the same
time reducing maintenance and work interruption costs.
Contrast a "dump disposal" operation (Figure 13-1) with a
planned coal refuse site (Figure 13-2) which is constructed
according to methods and techniques well known to the soil
mechanics and earth dam engineering community—The
planned disposal site has a good appearance and displays
characteristics of planning and management. When the
mining operation terminates, abandonment procedures are
complete and the site will remain environmentally accep-
table. The preplanned site has a very low hazard potential
and, in many cases, is available for other uses including
agriculture and recreation. The properly built refuse
deposit is not susceptible to combustion nor does it
contribute significantly to water supply degradation.
The development of an effective, economic and
environmentally acceptable refuse disposal system cannot
rely upon chance or accidental design. Rather, it must be
400
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Figure L3-1
Specific Gravity Results for Fine Coal Refuse
^
Figure 13-2
Common Characteristics - Coarse Coal Refuse
401
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the result of systematic development and compilation of
data and information utilized in a refined engineering
effort to develop an overall plan to encompass the life of
the disposal facility from original construction through
operation and maintenance to final abandonment.
The basic data required for a decision to open or
reactivate a mine are usually coal seam and coal market
data. If the mining company has the coal reserves avail-
able to meet a given set of market conditions (the physical
and chemical composition of the coal product along with
the basic price information), the approval is given to
prepare an economic and engineering study of the proposed
mining operation. Once a mining method and preparation
plant process, which together satisfy the basic coal seam
and coal market data, have been adopted, initial refuse
production estimates can be made concerning the size
range, the qualities and the quantities of the various
sizes which will be produced. Since the size range of the
refuse material will have a controlling influence on the
type of disposal facility that can be utilized for
effective long term storage, a site availability study
with this as its prime datum should be inititated. For
example, if large amounts of plant water with suspended
solids are to be produced, a large cross-valley impound-
ment may be the best type of disposal facility for this
type of refuse product, but a suitable site for such an
impoundment may not be available.
The site availability study would include
considerations of both underground as well as surface
refuse disposal sites. Modern day land values and the
consequences of environmental impact should not be
overlooked when evaluating underground sites, even though
the engineering and operating restrictions may appear to
402
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be greater. The disposal system capacity requirements
should be treated somewhat separately from the disposal
type selection in order to define what amounts of the
various size ranges might best be adequately handled
together or, conversely, which should be handled separately.
As in the cross-valley site mentioned above for large
volumes of plant water with suspended solids, perhaps
there are also significant quantities of coarse refuse
which if placed in the cross-valley fill area might
utilize too much of the disposal capacity of that site and
would, therefore, be better handled at another site.
The site availability studies should be used as an
interactive feedback to the preparation plant process,
assuming the coal seam and coal market data permit modifi-
cations to the plant flow sheet, through the mining method
selection to consider any feasible alternatives, and back
again to the disposal size and capacity requirements for
another disposal site type selection. This process can
iterate as many times as the project evaluator feels are
economically fruitful, but in most cases, the number of
available sites will serve to govern the number of
evaluations that can be performed.
Once a disposal site (or sites) has been selected and
the type of refuse deposit determined, selection of the
\
materials handling system can proceed. While this may seem
to be primarily an economic analysis to achieve the lowest
combined capital and operating costs, the impact of the
materials handling system on the engineering properties of
the deposited refuse material cannot be overlooked. These
properties can be significantly affected by the selection
of a particular method of materials handling, or by the
particular manner in which a materials handling system is
operated. For example, for many years coal refuse has been
403
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dumped from aerial trams with no recognition of the
potential influence on engineering properties of refuse
materials, such as stratification and permeability, by
the method being used. The addition of bulldozers and
compactors to the handling system in order to develop a
more acceptable end result, may make the aerial tram
system acceptable to a given set of site and operating
conditions, even though the improvement will result in an
addition to the capital and'Operating costs.
The final step in the disposal system requirements
development is an economic consideration of the overall
system configuration. If the economics appear to be
unrealistic or unattainable for a given project, reason
dictates a recycling through the mining method selection
phase to achieve, if possible, an economically acceptable
disposal system. Figures 13-3 and 13-4 are flow charts of
a Refuse Disposal Systems Development Procedure.
13.2.2 Refuse Disposal Site Selection Criteria
Site investigations must consider the effect of refuse
disposal practices on all environmental factors, not only
factors which might be affected by catastrophic embankment
failure. The primary environmental factors to be con-
sidered are water quality, air quality, sedimentation,
erosion, fish and wildlife, forestry and general aesthetics.
These factors should all be considered at an early stage
during the investigation, so that environmentally poor
sites do not receive undue emphasis. It is important that
all of these factors be considered together with equal
weight, at least in the general overview. Unless an over-
all perspective is maintained, there is a tendency to
give one or two environmental factors unbalanced weight at
the expense of others. This environmental perspective must
also include real-world socio-economic factors so that a
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REFUSE DISPOSAL SYSTEM DEVELOPMENT FLOW CHART
DEFINE REFUSE
SIZE RANGE
QUANTITIES
DISPOSAL SYSTEM
CAPACITY
SITE AVAILABILITY
STUDIES
SURFACE
UNDERGROUND
MATERIALS HANDLING
SYSTEMS
CAPACITY
PROCESS
ENGINEERING PROPERTIES
OF REFUSE MATERIALS
DUMP. OR
IMPOUNDMENT DESIGN
MATERIALS
CRITERI
PROCEED
I MINING METHOD L
COAL
SEAM
DATA
PREPARATION PLANT PROCESS
I
1
MARKET
DATA
Figure 13-3
405
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REFUSE DISPOSAL SYSTEM DEVELOPMENT FLOW CHART
SYSTEM REQUIREMENTS
TYPES OF
i. CAPACITY
3. SHE AVAILABILITY
4. lift I LOCATION OF DEPOSIT
9. MATERIALS HANOI INO SYSTEM
BUS 1C
ECONOMIC
CONSIDERATIONS
REGULATORY
AGENCY
(PERMITS. ETC.)
DISPOSAL FACILITY
DESIGN CONSIDERA1IONS
I. SHE CHARACTERISTICS
2. MATERIAL CHARACTERISTICS
3. DESIGN CRITERIA
PRELIMINARY DESIGN ANALYSIS
REFINED
ECONOMIC
CONSIDERATIONS
REGULATORY
AGENCY
(PRELIM. PLANS)
FINAL PLAN DEVELOPMENT
PRELIMINARY LAYOUT
SURFACE REQUIREMENTS
EQUIPMENT REQUIREMENTS
PERSONNEL REQUIREMENTS
COMPARISON OF ALTERNATIVES
FINAL
ECONOMIC
CONSIDERATIONS
NO
VES
FINAL PLAN DEVELOPMENT
S. ADOPTION OF FINAL PLAN
7. FINAL DESIGN ANALYSIS
B. PERSONNEL RESPONSIBILITIES
S. RECORDS ( REPORTIN6 PROGRAM
10. BUDGET OR FUNDING REVIEl
AND ALLOCATION.
NO
YES
CONTINUING STUDIES
OPERATING NEEDS
INSPECTION AND REVIEI
INDICATORS.
MONITORING INDICATORS
COST EFFECTIVENESS
UPDAIEO RECORDS ANO
REPORTING PROGRAM.
Figure 13-4
406
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negative approach is avoided. It is very easy to point out
existing and potential problems without relating them to
the whole picture. A positive and practical approach is
required that may require elements of compromise.
To a large degree, the success or failure of an
existing or proposed refuse embankment is dependent upon
how ground water is controlled. This control applies to
seepage conditions through both the foundation and the
embankment. The introduction of water into and earth or
coal refuse embankment is probably the greatest single
factor influencing the stability of the embankment.
Therefore, investigation of permeability characteristics
of embankment and foundation materials is essential. In
addition, percolation of water through coal refuse mater-
ials often results in degraded water, usually highly acid,
which can pollute waters downstream from the site. If
the dump is burning, seepage water may be thermally
degraded, or even in a gaseous state. Temperature can
affect both seepage rates and the quality of water.
Hydrogeologic investigation should include analysis of
foundation materials, both solids and bedrock, and analysis
of embankment materials. Both hydraulic characteristics
and water quality considerations should be included in
these analyses.
13.2.2.1 Hydrologic Investigations—Hydrology deals
with the quantities, distribution and circulation of
precipitation and water both in the atmosphere and on the
land. Hydrology is the science used to relate the
phenomenon of precipitation to surface runoff. This runoff
must be either impounded or routed past any restriction in
its path or serious erosion or failure could result. The
importance of performing an adequate hydrologic investiga-
tion to evaluate the impact of precipitation on an
407
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impoundment and the possible hazard that could result from
an adverse combination of hydrological factors which could
produce unusually severe flood conditions, therefore,
cannot be overemphasized.
A flood, as defined herein, is any relatively high
flow that overtops the natural or artificial banks in any
reach of stream and consequently constitutes a hazard to
structures which lie along or partially block the natural
drainage path. Where the stream channel is blocked by a
coal refuse disposal structure, high precipitation and
possible overtopping of the structure, resulting in
embankment failure with the consequent release of impounded
water, constitutes a severe hazard. A common mode of
catastrophic failure for many types of earthfill structures
is initial overtopping by stored water resulting from the
lack of adequate flood bypass facilities, such as spillways
or control structures. Once overtopped, an earthfill
structure may fail in minutes.
Flood flows are normally the: result of intensive
precipitation. However, the amount of water that directly
becomes runoff and the speed at which this runoff accumu-
lates and forms a flood peak can vary substantially because
of different terrain conditions. Once the precipitation
reaches the ground, the runoff may be delayed or modified
by such factors as freezing and thawing, vegetal cover,
antecedent precipitation and soil moisture, land use,
infiltration which relates to the type of soil and basin
geometry which relates to the size, shape and slope of the
drainage area. Generally, these factors are relatively
similar for specific regions. However, there can be
substantial differences within a region and care should be
utilized to recognize these differences.
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The climatic conditions which are responsible for the
rainfall and snow can also vary significantly within a
region. Localized storms, as well as large regional
storms, would, in fact, be expected to vary, with nonuni-
form precipitation intensities and durations occurring
simultaneously throughout the entire area. All these
factors, those relating to precipitation and those relating
to ground conditions, must be considered if a realistic
and safe design of a coal refuse deposit which can safely
pass flood flows is to be accomplished. Moreover, all of
these factors are an established part -of ordinary earth dam
design procedures.
In addition to the previous factors, small rural
watersheds, due to overland flow, have different runoff
characteristics than larger ones. Overland flow is that
water which travels over the ground surface to a water-
course and is the dominating factor for small watersheds.
Because of the overland flow factors, small watersheds are
more sensitive to high intensity rainfall of short dura-
tions and to land use. Small watershed are defined as a
watershed of 10 square miles or less. The effects of
channel flow and basin storage suppress these sensitivities
on larger watersheds. The significance of all this is that
a short, intense storm would cause a high, flashy, flood
peak on a small watershed and a lower, though longer
lasting peak on a larger one. This implies that basic
hydrologic data collected by the U.S. Geological Survey
and other agencies on larger streams throughout the country
over a long period of time cannot always be readily
transposed from large, nearby watersheds to smaller ones,
without major modifications being applied to the data.
The same applies for design techniques developed for
impoundments on large watersheds.
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One of the more critical phases of hydrologic planning
relates to the determination of a peak design flood.
Designing for the flood with a recurrence interval of once
in ten years or once in one hundred years, or any other
flow below that which is considered the maximum possible
flood involves a calculated risk because there is always a
chance that a maximum possible storm may occur. Localized
thunderstorms represent a particular threat to a small
watershed. The chance does exist of an extremely intense
storm occurring over a very small area, one square mile
or less, in an area such as the Appalachian region and such
events do occur each year. However, the magnitude of the
localized runoff from such a storm would represent a
relatively rare event for a specific watershed as a whole
and could have a theoretical recurrence interval of a
500 year or even a 1,000 year flood if applied to an
entire large watershed.
The selection of a design frequency must rest on
economic analysis policy decisions and local practice,
after a careful evaluation of the consequences of a failure
are ascertained. As a rule, some risk not associated
with the loss of human life must be accepted. The degree
of risk depends on flood characteristics and potentialities
in the basic and on the extent of development downstream
of the proposed or existing deposit.
Flow frequency analysis is used by engineers as an
aid in the evaluation or design of water-use or control
projects. Such an analysis provides the final solution for
a flow problem in some cases, but in most cases, the
analysis is only one of the steps in an engineering study
in which the project evaluation or design must advance
beyond the scope of flow frequency analysis. In the latter
case, determination of the probable maximum flood is often
required by regulatory agencies.
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A flow frequency analysis consists of a study of past
records of flow, followed by a statistical estimate of
frequencies of future flows. If such records are avail-
able and cover a period of 20 years or more, the flood
flows shown by the records may be analyzed to provide
flood frequency values. Outstanding flood events can be
analyzed to provide runoff factors for use in determining
the probable maximum flood.
Flow records which cover only a few years may not
include any flood of great magnitude and should not be
used without comparing the results with data from nearby,
watersheds which have similar runoff characteristics.
However, analysis of the results may give some or all of
the runoff factors needed to compute the probable maximum
flood.
Statistical analysis of flow records does not provide
reliable estimates of probable maximum flood flows. The
determination of the probable maximum flood should be based
on a study of storm potential, and runoff distribution as
related to the physical characteristics of the watershed.
Generalized charts for estimating probable maximum
precipitation east of the 105° meridian are published in
Technical Report No. 40, U.S. Weather Bureau, Department
of Commerce.
Step by step procedures for computing the probable
maximum flood are presented in Design of Small Dams, Bureau
of Reclamation, Department of the Interior, 1965, p. 19-61.
These procedures cannot usually be applied to small water-
sheds since rainfall and runoff data are often lacking and
bacause of the widely varies physical nature of small
basins.
When basic data is insufficient or lacking, empirical,
or semiempirical methods are used for estimating peak
-------
runoff from small watersheds. Many of these methods are
inadequate for evaluating the hydrologic factors involved
and the results obtained are often unreliable. The better
methods for estimating peaks, when historic and other
hydrologic data are unavailable, are those which correlate
such factors as rainfall intensities, land use, watershed
dimensions, slope and frequency of occurrence which have
been developed and tested for a specific region. Several
of these methods and a brief description are listed below:
1. The U.S. Bureau of Public Roads Method—This
method makes use of a topographic index and a
precipitation index. These indices vary from
place to place, resulting in a series of
relationships, expressed as curves, for different
parts of the United States.
2. The Cook Method—U.S. Soil Conservation Service—
This method uses an empirical relationship
between drainage area and peak flow with modifi-
cations for climate, relief, infiltration,
vegetal cover and surface storage. Charts are
presented for easy application.
3. The Chow Method—relates peak flow to rainfall
excess and has charts for runoff, climatic and
other factors. Developed primarily for
Midwestern areas.
4. Various State Highway Methods—Many states have
developed their own data and methods. Some of
these provide fairly reliable results.
Procedures and references for using these methods are
presented by: Chow, V. T., Handbook of Applied Hydrology,
McGraw-Hill Book Company, New York, 1964, pages 25-16 to
25-25.
Maximum flood peaks do not always represent the most
critical aspect of flood flows. Since the majority of coal
refuse deposits are constructed on small watersheds and are
sensitive to high intensity rainfall of short duration, the
incoming peak flows resulting from such a storm will have a
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high peak flow but the volume of water contained by the
flood will not be exceptionally large because of the short
duration. Another storm with smaller rainfall intensities
but with a much longer duration can produce a larger
volume of water. In situations involving coal refuse
impoundments, various storm conditions should be considered,
13.2.2.1.1 Seepage and Pore Pressure The destructive
power of water is well recorded in the annals of history.
Water moving through soil pores and rock fractures is
capable of exerting forces that can cause massive land-
slides or destroy major engineering works. Seepage theory
has been developed in great detail in many textbooks;
however, discussion relating to practical application of
the theory is available in only a few. As with most
analytical tools available to the engineer, mathematical
theory is the basis of seepage analysis. It is, therefore,
incumbent upon the engineer to develop these parameters
used in the analysis in a way that is consistent with the
theory and accurately reflects the actual conditions.
In performing a seepage analysis, even though the
analysis itself may have a high degree of reliability, the-
result may be greatly in error if the assigned permeability
is in error by a factor of even 100. Since permeability
may change during the life of the structure, and labora-
tory test results can easily differ from field results by
a factor of 1,000, most experienced engineers regard
seepage theory as a means of predicting the general order
of magnitude of problems and to indicate potential problem
areas that require special design consideration. In this
light, it is easily understandable that there exists no
substitute for field observations and periodic surveillance
of earth structures such as coal refuse dumps and
impoundments.
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The need for control of pore water pressure and seepage
in earth structures is well recognized. The forces of
gravity are constantly being exerted downward on all soil
and rock. These same forces act on water in soil voids
and thus seepage forces develop within the soil mass.
Under the proper combination of soil and pore water
conditions, the potential for mass instability can become
great.
Pore water pressure and seepage forces are quite
different; in fact, they are virtually opposite. Pore
water pressure has to do with the motion of the embankment
material, while seepage forces are caused by the motion of
the water through this material.
When an embankment is placed, the lower layers, both
of the foundation and the embankment material, compress
under the load of the material above. The individual
particles do not themselves compress, rather they rearrange
themselves under the force of the weight above. As a
result, compression necessarily leads to a reduction in the
relative amount of empty space (the volume of the so-called
"pores") in the soil.
If the pores contain any water, this reduction in
pore volume may lead to a saturated condition where the
pores are completely filled. Even if the material in the
embankment was not saturated when it was placed, it may
readily become so as it compresses (this compression is
called "consolidation"). Reaching saturation is a critical
condition, due to the incompressibility of water. Once
saturation is reached, no more consolidation can occur
until some of the water has been squeezed out of the
weighted, or loaded, material. In the interim any added
load will literally "float" upon the water in the soil,
creating only water pressure rather than consolidation.
414
-------
This pressure, i.e., the water pressure over and above
that caused by the weight of the water itself, is called
excess pore water pressure.
Excess pore water pressure is serious for several
reasons. First, as long as it exists, say in the bottom
layer of an embankment, the material above that layer is
not exerting its full weight upon the foundation. But the
frictional resistance to' motion over the foundation is a
direct function of how much weight is exerted. If most of
the weight is being carried by the water and is thus
unavailable for frictional resistance, the entire embank-
ment might slide forward propelled by the water impounded
behind it (indeed, some witnesses have spoken of dams
which failed in this way as "opening like a gate on
hinges").
Even when no water is impounded, as when an impound-
ment is under construction or material is simply being
piled up, excess pore water pressure may cause failure
along an including surface because the weight of the
material above is greater than the frictional resistance
along the surface. Such a surface, or "failure plane",
may even form within a homogeneous mass of material,
leading to sudden and catastrophic failure.
It must not be thought that because excess pore water
pressure is a transient phenomenon it is thereby short-
lived. For a fine-grained material such as clay, silt or
fine sized coal, it might take a dozen years for the
excess pore pressure in a consolidating zone to fall by
one half. Total consolidation in clay can often take
a century, at least in theory. It is the great slowness
with which excess pore pressure abates in fine soil that
makes necessary the very flat slopes found on earth dams
built upon such material. These dams must be designed to
415
-------
float on the saturated soil, because it is not economical
to wait for even partial consolidation. However, in the
same terms, the coal refuse disposal area which is to be
developed over a period of years may be able to take
advantage of the partial consolidation which will occur
and use steeper slopes than those found in earth dams,
thus saving land area. Indeed, this partial consolidation
effect apparently accounts for the fact that many existing
mine refuse embankments stand at slopes which are deemed
impossible under conventional earth dam design theory.
The second serious consequence of excess pore water
pressure is that it causes seepage and seepage forces. In
order for the excess water to squeeze out of a consolidat-
ing mass it must flow through the pores of the material,
which causes a frictional force in the direction of flow.
Such forces are called seepage forces.
Seepage forces may be caused by conditions other than
excess pore water pressure due to consolidation; in fact,
they will occur wherever water flows or "seeps" through a
porous medium. Such forces are always present, for
example, in the lower layers and foundation of an embank-
ment, which impounds water, or in the hillside beneath a
perched or hilltop reservoir. Moreover, seepage forces
may act in any direction, depending upon where the water
must flow in order to reach lower pressure. Such
directions may be difficult to predict because the ease of
flow, or "permeability" may vary greatly from one direction
to another at any given spot. In general, however, the
seepage forces in an embankment which is consolidating will
be more or less horizontal and outward from the center.
These forces can be large and can contribute considerably
to the gliding-type failures described above.
416
-------
When impounded water seeps under an embankment, the
seepage forces at the "toe", or downstream edge, will often
be vertical as the water escapes from the ground. This
condition, which can be very serious, may sometimes be
recognized by such things as active seeps, boils or
quicksand near the toe or by a heavy stream flow in dry
weather. If such conditions are observed, action should
be taken at once to either lower the level of the impounded
water or alleviate the excess pore water pressure at the
toe by means of drains, because the toe of an embankment is
particularly critical to its stability.
If a condition of excess pore water pressure is
anticipated or is throught to exist, this can be detected
and monitored by a device called a piezometer. If piezo-
meters are installed when a disposal site is developed and
carefully monitored, they may be used to plan the placement
of material to achieve relatively steep slopes with safety.
Since the soil mass of slopes may contain moisture but
be free of excess pore water pressure and quite stable
because seepage forces have not developed, a knowledge of
internal water force is critical to safe and economic
design. Therefore it follows that adequate stability
anaylsis is contingent upon a thorough understanding of
the internal water conditions of dumps and embankments.
No engineering property of soil materials is more
variable than the coefficient of permeability. The three
areas that influence permeability are: 1) factors associ-
ated with the properties of the water or other permeant,
2) factors associated with the physical properties of the
soil, and 3) chemical effects of the soil-water system.
The following chart (Figure 13-5) by. Cedergren is for
inert soil particles; coal refuse has permeability
characteristics which also vary over at least this wide
a range.
417
-------
GRAVEL-
SAND
SILT
CLAY
f
;
•
^
•
•100.000 —
•1000
-10
•0.1
-0.001
-0.00001
1
RAKGE OVER
10 BILLION
TIKES.
Figure 13-5
Coefficient of Permeability (Ft/Day)
Although the quantity of seepage exiting an earthen
structure is important for dams, it has little consequence
in analysis of dumps and impoundments providing the
discharged water is controlled, i.e., internal soil erosion
(piping) is nonexistent and surface erosion is tolerable.
The crucial elements in a satisfactory stability analysis
are engineering properties of the material involved,
seepage forces, internal static hydrostatic pressure and
the upper boundary or line of saturation. This saturation
boundary is often referred to as the phreatic surface. It
is important to note at this point that a theoretical
seepage analysis may be a futile academic exercise if the
embankment construction technique is not known with reason-
able accuracy, if the operation of the impoundment is at
variance with the analysis, or even if the refuse material
changes as the coal seam characteristics change.
418
-------
The flow of water through a porous medium (soil) may
be represented analytically by the LaPlace Transform. This
transform governs the two-dimensional flow of an incompres-
sible liquid (water) through an incompressible porous
material (soil particles). Graphically the LaPlace
equation may be represented by a set of curves that, taken
as a group, are known as a flow net. The flow net has been
generally accepted as a method of studying pore pressure
and seepage flow, and is widely used for evaluation of
seepage conditions in embankment type structures. For
practical solutions to engineering problems, mathematical
solutions have proven to be unmanageable even with the use
of sophisticated computer programs, but fortunately a
useful flow net can almost always be prepared by a
practiced soils engineer. The development of a useful
flow net, however, demands a knowledge of materials
behavior,as well as of the limitations of the boundary
conditions inherent in the mathematical analysis.
13.2.2.2 Stability Analysis In the last 20 years,
both understanding of soil shear strength by the engineer-
ing profession, and methods of laboratory testing and soil
sampling have been vastly improved. In addition, improved
methods of computations for stability analyses have been
developed. As a result of this progress, and also because
of the great need which exists for an analytical means of
estimating the margin of safety of earth dam embankments
against shear failure, stability analyses have become
firmly established analytical procedures. It must be kept
in mind, however, that nearly all computation procedures
are based on assumptions which are often, of necessity,
gross simplifications of conditions which may actually
exist. Therefore, stability analyses should be considered
primarily of value as a tool to evaluate an embankment's
419
-------
relative stability rather than a procedure which produces
absolute, inflexible numerical results. There is no
substitute for practical experience and the judgment which
it brings. Great caution is required in the interpretation
of the results obtained by stability analysis which have
been tested primarily upon well-compacted, quickly erected
embankment dams. When one uses the absolute numerical
value of the safety factor to justify the acceptability of
a given design, reliance is being placed on several
assumptions, the validity and limitations of which are
often not well understood. But it is easy to show that
small changes in assumed shear strength parameters or pore
water pressure cause appreciable differences in the calcu-
lated results. Therefore, because the specific gravity of
the sludge derived from the separation process is very low
and the average shear strength parameter high, a doubly
difficult problem exists when sludge forms the foundation
for a coarse refuse deposit.
13.2.2.3 Physical Properties of Coarse Coal Refuse
The physical properties results presented herein were
compiled from the test results produced by W. A. Wahler and
Associates in conjunction with research work performed for
the U.S. Bureau of Mines and the Mining Enforcement and
Safety Administration, and investigatory and analytical
work for coal mining companies. Several other references
were reviewed and, where available, appropriate data have
been included. Two references in particular, "Tentative
Design Guide for Mine Waste Embankments in Canada",
prepared for the Mines Branch Mining Research Center, and
"Spoil Heaps and Lagoons", a technical handbook prepared
by the National Coal Board of England, contained specific
test results which have been included for comparative
purposes. Other than the two cited references, and the
420
-------
results from W. A. Wahler and Associates' detailed work
at some ten sites located in West Virginia, it must be
concluded that detailed, publicly available information on
the index and engineering properties of coarse coal refuse
is limited. The data which are presented, however,
represent a cross section of industry practices and are
probably indicative of results that would have been devel-
oped had there been a greater amount of data available for
review.
As mentioned previously, the effect of consolidation,
the influence of degradation (caused by natural weathering)
and accelerated weathering associated with burning refuse
dumps are important areas of needed future research. The
data on the physical properties of coarse coal refuse as
presented herein indicates that a breakdown or degradation
of the coarse coal refuse does occur. However, the data
are inconclusive with regard to the specific influence
that such degradation may have on the material properties
characteristics.
13.2.2.3.1 .Grain Size Distribution This gradation
results for 128 samples of coarse coal refuse are presented
on Figure 13-6 in the form of a range of all samples
tested, a range encompassing 70 percent of all data, and
the arithmetic average. These data represent gradation
results from burning as well as nonburning refuse dumps
which were constructed by aerial tram or random truck
dumping methods. While these data have a rather broad
range, elimination of the upper and lower 15 percentiles
reveals a reasonably narrow range for the remaining 70
percent. The heights of the refuse dumps from which the
data were obtained range from tens to several hundreds of
feet. Similar data on grain-size distribution from the
National Coal Board of England and the Canadian Mining
421
-------
-•
- I
•
HYDROMETER ANALYSIS
T > HE DEADI
:
•-
SIEVE ANALYSIS
U S SI«»0««0 SEHIES . CLEAR SQUAIIE OPEHIUSS
3 -8" 3 4" 1-1-2" 3"
S 50
>
45 KIN 15 KIN 50 DIN. I9MIN. 4 KIN | HIN. 200 100 50 30
o o
OiA«EIE« OF PHIICLE 111
CLAT CLASTIC) TO SILT (»0»-fLA SI I C )
SAND
GRAVEL
K E T
»VE»A6E SRAOATIOH FOR 128 SAMPLES FRON 8 SITES
RANGE ENCOMPASSING 70 PERCENT CONFIDENCE LIMITS
RANSE OF ALL SAMPLES
-------
Research Center are presented on Figures 13-7 and 13-8,
respectively. The data shown on Figures 13-6 through 13-8
indicate the same general band of gradation results.
Sufficient data were not available from these sources to
determine the middle 70 percent distribution of test
results.
The effects of particle breakdown due to weathering
and handling are clearly shown on Figure 13-9, which
presents the average gradation results of "fresh" coal
refuse from three sites, as well as the average gradation
for the 128 samples referenced on Figure 13-6. These
samples were obtained directly from the surface of the
dumps within one day after deposition. When comparing
the average gradation results of all samples with those
of the fresh material, it is observed that the material
when originally deposited on the dumps was classified as
well-graded gravel with more than 60 percent of the
material coarser than the #4 sieve and less than 10 percent
finer than the #200 sieve. The gradation results for the
average of all samples tested, however, indicate that less
than 40 percent of the material is coarser than the #4
sieve and approximately 15 percent of the material is finer
than the #200 sieve. The approximate parallel nature of
the two average gradations shown on Figure 13-9 below the
#4 sieve indicates that the majority of the breakdown is
occurring on the plus #4 particles sizes.
Only 18 gradation results were available for complete-
ly degraded coarse refuse, commonly referred to as red
dog. Although these results are not presented herein, the
average gradation for the 18 samples was almost identical
to that of the average for the 128 samples referenced on
Figure 13-6. These results could be misleading, however,
because sampling and testing of this type of material is
423
-------
•
25 HR. 7 HR.
45 DIN. 15 MIN
100
90 -
1
HYDROMETER ANALYSIS
ii HE it is mss
60 KIN. 19 MIN. 4 MIN.
SIEVE ANALYSIS
U S 51 IKDiRD SERIES
CLE»B SQUIRE OPENINGS
2 50 -
OUKEtER Or URTICLE III II I L L I HE TE R S
CLAY i'i.«svci TO SILT («ON-PL« S I i c )
SAND
GRAVEL
1
K E Y
DATA FROM SPOIL HEAPS AND
LAGOONS NATIONAL COAL
BOARD-TECHNICAL HANDBOOK
ENGLANO-1970.
RANEE FOR 95 PERCENT OF ALL SAMPLE:
RANGE FOR ALL SAMPLES TESTED
-------
-•
•
-
f
-
*
a
23 Nil, 7 HR.
49 KIN I! KIN.
100
HYDROMETER ANALYSIS
Till KADIHII
60 MIN. 19 KIN. 4
SIEVE ANALYSIS
u.l. iTiiDAig id in
JO 30
CLE4I
0'E«i«iS
Q turn ar »»TICLI n IULHITIII
CLAT
TO IILT (non-PUIT i : )
SANO
I coon
MJI
COMII
HAT* FROV TECHNICAL IUUITIN
TIU3 BEMRTKINT OF fNEISY,
IIINII AND MIOHCII OMAIA,
CWAOA 1|72.
KE Y
KINII FOR 8! rixGiNT or ILL IUPLII TIITID
'o» ALL itipi.il TIITID
-------
HYDROMETER ANALYSIS
: •
J
D
..
8
,
t
B
K
B
H<
ri
:
s; so
5 50
S IEVE ANALYSIS
;i f » R SQUfcRE OPENINGS
3'B" 3 4" 1-1-2" 3"
45 DIN 15 KIM 60MIN. 19 KIN. 4 KIN, I KIN. 200 100
Of Pi»7,Ci.c :» m LI
CLAT lH»S-:C) TO SILT (NON-PLIST1C)
SAND
COIISE
GRAVEL
K E T
AVERAGE GRADATION OF FRESH WASTE FROM 3 SITES
RANGE OF GRADATION OF FRESH »ASTE
AVERAGE GRADATION FOR 126 SAMPLE! TAKEN FROM
VARIOUS LOCATIONS AND DEPTHS OF EXISTING
DUMPS OR IMPOUNDMENTS (SEE FlOURE NO. V-l).
-------
extremely difficult. When the burning of a refuse dump
goes unchecked, the coarse refuse sometimes fuses together
into blocky masses with maximum dimensions as great as one
to four meters; other times, the burning produces large
lenses of fine, powdery material.
13.2.2.3.2 .Atterberg Limits The majority of the
coarse refuse material is nonplastic. A total of 17
samples out of some 150 samples tested in the laboratory
exhibited some plasticity and results are presented in
Figure 13-10. The average results indicate a liquid limit
of 30 percent and a plasticity index of less than 10.
13.2.2.3.3 Specific Gravity Specific gravity values
for the'coarse coal refuse vary from about 1.6 to greater
than 2.4, depending upon the composition of the materials.
The specific gravity results for 37 coarse refuse samples
are presented in Table 13-1, below.
Table 13-1
Specific Gravity Results for Coarse Coal Refuse
Number of Samples
3
9
13
4
8
Range of Specific Gravity
1.60 - 1.80
1.81 - 2.00
2.01 - 2.20
2.21 - 2.40
2.40
Average Specific Gravity = 2.14
13.2.2.3.4 Natural Water Content and Dry Density
The natural water content and dry density of coarse coal
refuse depends directly on the method of disposal used and
whether or not the dump is burning. Results for the
in-place water content and dry density obtained from eight
sites in West Virginia are summarized in Figures 13-11 and
427
-------
80
70
60
50
3 30
CH
OH
CL
HH
10
CL
CL-ML
ML
10 20 30
40 SO 00 70 30 90 100 110 120
LIQUID LIMIT (*)
X E Y
RANGE OF UTTERBERC LIMITS FOR 17 SAMPLES.
Source: W.A. Wahler s Associates
Figure 13-10
ATTERBERG LIMITS
COARSE COAL REFUSE
428
-------
13-12, respectively. These data were obtained from both
field density testing and measurements obtained in the
laboratory. The water content results shown in Figure
13-11 indicate a range from 2 percent to 28 percent, with
approximately 90 percent of all data falling between 4
percent and 16 percent. The arithmetic average of the
natural moisture content based on dry weight for the 141
samples tested was 10.4 percent. In-place dry density
results, shown on Figure 13-12, indicate a wide range from
60 to 116 Ib/cu ft (pcf), with about 84 percent of the
results higher than 80 pcf. The arithmetic average of the
137 samples was 90.4 pcf.
As mentioned previously, it is very difficult to
obtain undisturbed samples of burning coal refuse. The
excessively high temperatures associated with this problem
(above 500° F.) makes drilling and sampling of these
materials hazardous. Obviously at these elevated tempera-
tures, all free water is driven off. The natural moisture
content and dry density data presented on Figures 13-11 and
13-12 contain the results of only a few samples obtained
for burning coal refuse. More research regarding the
physical composition and engineering properties of burning
coal refuse is needed.
13.2.2.3.5 Compaction Characteristic; A total of 38
compaction tests were performed on coarse coal refuse in
accordance with ASTM D-1557-70, modified to 20,000 ft-lb/cu
ft compactive energy. The results are presented in Table
13-2.
The compaction test data presented in Table 13-2
indicate a broad range in maximum laboratory densities from
76.2 to 123.7 pcf. A somewhat progressive increase in
maximum laboratory density can be seen when the data are
grouped according to ranges of specific gravity. The major
429
-------
10 12 14 16 18 20
NATURAL MOISTURE CONTENT. *
AVERAGE = 10.71
THE NATURAL MOISTURE CONTENT DATA SHOWN HEREON ARE REPRESENTATIVE
OF 141 SAMPLES OBTAINED AS EITHER IN-PLACE DRY DENSITY OR UNDISTURBED
TUBE SAMPLES FROM B SITES IN WEST VIRGINIA.
W.A. Wahler & Associates
Figure 13-11
NATURAL MOISTURE CONTENT
COARSE COAL REFUSE
430
-------
110
120
DRY DENSITY, pel
AVERAGE = 90.4 pcf
NOTE: THE DRY DENSITY DAT* SHOW HEREON ARE REPRESENTATIVE OF
134 SAMPLES OBTAINED AS EITHER IN-PUCE FIELD DENSITY OR
UNDISTURBED TUBE SAMPLES FROM B SITES IN »EST VIRGINIA.
Source: W.A. Wahler & Associates
IN-PLACE DRY DENSITY
COARSE COAL REFUSE
Figure 13-12
431
-------
factors influencing the scatter of data are the difference
in specific gravity and gradation for the individual
samples tested.
Table 13-2
Compaction Characteristics—Coarse Coal Refuse
Number of
Tests
3
8
13
14
Range of
Specific Gravity
1.75 -
1.81 -
2.01 -
2.21 -
1.80
2.00
2.20
2.63
Laboratory Compacted Optimum Moisture
Maximum Dry Density, pcf Contents, %
Low
76.2
89.9
90.6
92.2
High
95.5
104.4
108.5
123.7
Average
87.7
98.6
102.5
109.4
Low High Average
7.5 19.5
7.5 14.0
6.5 11.5
7.5 15.0
12.6
10.5
9.7
11.7
13.2.2.3.6 Permeability The coefficient of permea-
bility as used by the soils engineer is the superficial
velocity of water as it passes through a soil under a unit
gradient. The value of the coefficient of permeability
reflects the ease with which water will flow through a soil
and must be known in order to calculate the quantity of
flow. The range of permeability reflects the ease with
which water will flow. The range of permeability for soils
is extremely great, varying from greater than 1 cm/sec
(1,000,000 feet/year) for clean gravels to 10~8 cm/sec
(0.01 feet/year) or less for clays.
Approximate values of permeability can be obtained by
field testing procedures. The reliability of the values
obtained depends on the homogeneity of the stratum tested
and on certain restrictions of the mathematical formulas
used. If reasonable care is exercised in adhering to the
recommended procedures (see Hovrslev, 1949, or United
States Bureau of Reclamation Test Method E-18), useful
results can be obtained.
432
-------
Two methods of determining the coefficient of perme-
ability that are used most often in the field are the
infiltration or pumping-in tests and the pumping-out test.
In the first method, water is introduced into a drill hole
or test pit of known dimensions, and the rate of seepage
observed under a fixed or variable head. The second, and
less used method, involves the drawing out of water at a
constant rate from a drill hold and observing the rate of
drawdown on the water table in observation wells placed in
a geometric pattern, usually radially at various distances
from the point of water withdrawal. Interpretation of
test data must be made on the basis of simplified formulas
or flow net analyses with application of proper judgment
regarding geological factors such as channeling, layering
and the anisotropic characteristics of the deposits.
The permeability characteristics of the coarse coal
refuse materials were evaluated by reviewing both field
and laboratory test data. Values of the coefficient of
permeability range between 10~2 and 10~6 cm/sec, with a
typical value of 10~^ cm/sec. Similar permeability data
are presented to the National Coal Board of England
reference for coarse coal refuse with values ranging from
10~2 to 5 x 10~6 cm/sec. The ratio of horizontal to
vertical permeability, which is needed to correctly con-
struct a flow net for a given impoundment, does not seem
/
to vary significantly for the sites investigated. Unlike
compacted material, which usually exhibits a ratio of k^
to kv on the order of 10 to 50, the permeability results
of the corase refuse indicate a ratio of less than 10,
with a majority of the results less than 2. The low ratio
of kn to kv is undoubtedly due to the lack of compaction
and the generally loose nature of most of the impoundments
studied.
433
-------
13.2.2.3.7 Compressibility The compressibility
characteristics of the coarse refuse are difficult to
investigate in the laboratory because of the coarse nature
of the materials. Data from saturated, isotropically
consolidated triaxial tests, as well as one saturated
anisotropically consoldidated triaxial sample, with average
initial densities varying from 85 to 95 pcf, were evaluated
and the results are presented in Figures 13-13 in the form
of axial strain versus maximum effective principal stress
for the sample consolidated under Ko conditions (no lateral
deformation) and volumetric strain versus maximum effective
principal stress for the isotropically consolidated
samples.
A range of volumetric compression of 3 to 6 percent
was observed for the anisotropically consolidated samples
as compared with 9 percent for the isotropically consoli-
dated samples at 100 psi maximum principal effective
stress. This stress corresponds to an embankment height of
about 150 feet. Because of the relatively high permeabi-
lity value of the coarse material, the time delay
associated with the consolidation process is extremely
short. In other words, the straining within a saturated
embankment due to a load application would occur very
rapidly. Additionally, the magnitude of the volumetric
compression is considered to be high when compared to an
average value of less than 3 percent volumetric strain at
100 psi for a well-compacted material with similar
gradation characteristics to that of the coarse coal
refuse.
13.2.2.3.8 Shear Strength Shear strength parameters
of the coarse refuse material were determined from
laboratory triaxial tests performed on 51 samples, and are
presented in Figure 13-14 in the form of shear strength
434
-------
1.5
4.5
7.5
AVERAGE
COMPRESSIBILITY
FROM 128 ISOTROPICALLY
CONSOLIDATED TRIAXIAL
SAMPLES
~r~n mi
RANGE OF DATA
OBSERVED FROM
Ko CONSOLIDATION
ON LABORATORY
FABRICATED AND
UNDISTURBED TUBE
SAMPLES
to too
MAXIMUM PRINCIPAL EFFECTIVE STRESS (f,). pll
1000
Source: W.A. Wahler & Associates
COMPRESSIBILITY CHARACTERISTICS
COARSE COAL REPOSE
Figure 13-13
435
-------
20
NOTE: THE SHEAR STRENGTH PARAMETERS SHOIN HEREON IERE DETERMINED
FROM 32 I CD TRIAXIAL SAMPLES.
-------
versus normal stress for both effective and total stress.
These samples consisted of either laboratory fabricated
or undisturbed tube samples and were tested under ICU test
conditions. The shear strength parameters for the coarse
refuse materials, based on effective stresses, vary from
34° to 41°, with essentially zero cohesion intercept. It
is interesting to note that the dry density of the triaxial
samples varied considerably, and yet the effective stress
friction angle was found to vary less than 7°. The influ-
ence of the scatter in density is more reflected in the
shear strength paramteres based on total stresses, wherein
the friction angle varied from a value less than 15° to
approximately 20° with 7 psi cohesion intercept.
The relatively high values of shear strength of the
coarse refuse materials indicate one very important point.
Since the material is inherently quite strong when
compared to other construction materials, if proper
construction techniques are utilized, a dam or dump made
with these materials, utilizing current earth dam design
standards, can provide a safe, adequate structure.
13.2.2.4 Physical Properties of Fine Coal Refuse
The physical properties of the fine coal refuse materials
similar to those for the coarse materials discussed in
13.2.2.3 were also evaluated for the eight sites in West
Virginia. Unlike the coarse materials, which are conveyed
to the disposal area by aerial tram or dump truck methods,
the fine materials are conveyed to the disposal area in a
slurry. The physical properties of these materials,
particularly in grain-size distribution and resulting
in-place dry density, are significantly influenced by the
location of the discharge line and the distance of flow
before these materials arrive at the settling pond.
437
-------
13.2.2.4.1 Grain-size distribution—The gradation
results for 63 samples of fine coal refuse collected from
eight sites in West Virginia are shown on Figure 13-15.
The results, presented in the form of a range of all
samples tested, a range encompassing 70 percent of all
data, and the arithmetic average, indicate that the fine
coal refuse materials have an average of 45 percent of the
material passing the #200 sieve. The range in percent
passing the #200 sieve varies from approximately 18 percent
to 98 percent, which merely reflects the influence of the
point of discharge and the settling characteristics of
the fine refuse materials.
13.2.2.4.2 Plasticity characteristics—The minus #40
fraction of the fine refuse materials is nonplastic.
Numerous attempts were made to perform Atterberg Limits
testing on the fine refuse materials and although a liquid
limit ranging between 30 and 50 percent was achieved on
some samples, it was not possible to roll threads to 1/8
inch diameter in order to determine the plastic limit and,
therefore, the material must be classified as nonplastic.
13.2.2.4.3 Specific gravity--Specific gravity values
for the fine coal refuse vary from about 1.3 to 2.2,
depending upon the percentage of coal in the material. The
specific gravity results for 30 fine refuse samples are
presented in Table 13-3.
13.2.2.4.4 Natural water content and dry density—
The natural water content and dry density of the fine
refuse materials were determined from both field density
and undisturbed tube samples. Results of the natural water
content for 87 samples are shown on Figure 13-16, in the
form of observed water content versus frequency of occur-
rence. A range in natural water content from 8 to 56
percent was observed, with an average value of 30.9 percent.
430
-------
U)
10
c
I
I-'
U1
HYDROMETER ANALYSIS
25 MR. 7 HR. T1"E 'E""1"
45 KIN, 15 "IN. 60 HIM. 19 HIN. 4 HIM. | >|N. 2
100
90
80
SIEVE ANALYSIS
U.S. STIUCUHO SERIES
100 50
ClEtR SQUARE OPENINGS
3/a" 3/4" 1-1/2" 3"
en
O
c
n
n
ra
s
>
$
3"
M
ro
fr
5>
tn
in
O
n
OI««EIE« OF PHIICLE IK II ILL I HE TC IIS
CLAY (PUSTIC) TO SILT (NON-PIAST 1C)
SAND
GRAVEL
FIRE
KEOIUK I CO>RSE
K E Y
AVERAGE GRADATION FOR 63 SAMPLES
FROM B SITES.
RANGE ENCOMPASSING 70 PERCENT
CONFIDENCE LIMITS.
RANGE OF ALL SAMPLES
-------
Source: W.A. Wahler S Associates
12 IB 20 24 28 32 38 40 44 43 52 58 80
NATURAL MOISTURE CONTENT, X
AVERAGE - 30.9*
NOTE: THE NATURAL MOISTURE CONTENT DATA SHOWN HEREON ARE REPRESENTATIVE
OF 87 SAMPLES OBTAINED AS EITHER IN-PLACE DRY DENSITY OR UNDISTUR8EO
TUBE SAMPLES FROM 3 SITES IN WEST VIRGINIA.
Figure 13-16
NATURAL MOISTURE CONTENT
FINE COAL REFUSt
440
-------
Table 13-3
Specific Gravity Results for Fine Coal Refuse
Number of Samples
8
15
4
2
1
Range of Specific Gravity
1.30 - 1.40
1.41 - 1.60
1.61 - 1.80
1.81 - 2.00
2.01 - 2.20
Average Specific Gravity = 1.53
A total of 78 field dry densities were determined for
the fine refuse materials and the results are presented in
Figure 13-17. The dry density results vary from 44 to 84
pcf with 85 percent of all data ranging between 48 to 68
pcf. The arithmetic average dry density was 55.2 pcf.
Although the density results are exceedingly low for
the fine refuse material, when compared to an average dry
density of 110 to 120 pcf for typical soil materials, the
void ratio of the fine-grain materials indicates a
generally close packing of the individual grains. An
average void ratio, which is a comparison of the volume of
voids to the volume of solids within a given sample, of
0.5 or less is not uncommon.
13.2.2.4.5 Compaction—The moisture density charac-
teristics of the fine refuse materials were determined
from a total of 15 samples compacted in accordance with
ASTM D-1557-70, modified to 2,000 ft-lb/cu ft compactive
energy. The compaction results are presented in Figure
13-18, in the form of maximum compacted laboratory dry
density versus moisture content. The data have been
grouped according to ranges of specific gravity and the
441
-------
20
10
30
40
50 60
DRY DENSITY, pel
70
80
AVERAGE = 55.2 pcf
NOTE: THE DRY DENSITY DATA SHOWN HEREON ARE REPRESENTATIVE OF
78 SAMPLES OBTAINED AS EITHER IN-PLACE FIELD DENSITY OR
UNDISTURBED TUBE SAMPLES FROM 9 SITES IN WEST VIRGINIA.
Source: W.A. Wah.lor K Associates
Figure 13-17
IN-PLACE DRY DENSITY
FINE COAL REFUSE
442
-------
Source: W.A. Wahler & Associates
RANGE OF MAXIMUM
DRY DENSITY FOR
B SAMPLES KITH
SPECIFIC GRAVITY
OF 1.4-1.7.
RANGE OF MAXIMUM
DRY DENSITY FOR
7 SAMPLES WITH
SPECIFIC GRAVITY
OF 1.3-1.4.
10 IS 20
MOISTURE CONTENT. *
NOTE: ALL TESTS PERFORMED IN ACCORDANCE IIIH ASTM 01357-70 MODIFIED
TO 20.000 FM.B/FT3 COMPACT I »E ENERflT.
COMPACTION CHARACTERISTICS
FINE-GRAINED COAL REFUSE
Figure 13-18
443
-------
results indicate that a maximum dry density between 57.5
and 66.5 pcf is achieved for a specific gravity between
1.3 and 1.4 and a range of 74.0 to 81 pcf is achieved
for specific gravity values between 1.41 and 1.70.
When the range of in-place dry density values pre-
viously referenced is compared to the maximum laboratory
densities, it is observed that the ponding methods being
utilized to dispose of the fine refuse materials result in
a relative compaction of approximately 75 to 85 percent;
however, the in-place moisture content is 10 to 20 percent
higher than the optimum moisture contents. If the
fine-grained coal refuse is to be used as a construction
material for water-retaining structures, the material could
be compacted by the use of mechanical compaction equipment
to higher densities than those determined for the in-place
materials. However, regardless of the density to which
the material is compacted, it must be recognized that the
low specific gravity and resulting in-place dry densities
could lead to piping or instability problems if the fine-
grained material is not properly ballasted, or confined,
by the heavier materials. On the other hand, the low
permeability of the fine-grained material will be necessary
to retain water. Most likely some form of zoned structure
will prove to be optimal.
13.2.2.4.6 Permeability—The permeability characteris-
tics of the fine coal refuse materials were determined by
thoroughly reviewing the disposal methods and laboratory
test results. This evaluation indicated that a significant
degree of anisotropy is developed in the fine-grained
refuse materials because of their method of disposal. The
fine-grained materials in the field are found to be highly
lenticular with stratifications varying from fractions of
an inch to several inches in thickness. The finest-grained
444
-------
silts (ML) usually constitute the thinner partings, and
probably reflect variations in inflow of the slurry. The
ML materials exhibit a coefficient of permeability of
about 10~7 cm/sec, whereas the fine- to medium-grained
silty sand (SM) which constitutes the coarser fraction of
the fine-grained material, has a maximum coefficient of
permeability of about 3 x 10~4 cm/sec. The ratio of
horizontal to vertical permeability for the fine refuse
material was found to vary between 15:1 to 100:1, with an
average value of approximately 25:1.
The National Coal Board of England reference indicates
a range in the coefficient of permeability of 10~3 to
5 x 10"^ cm/sec in the horizontal direction, and 10~6 to
7 x 10"^ cm/sec in the vertical direction.
The high degree of anisotropy of permeability values
for the fine refuse materials is extremely important to
recognize when considering the stability characteristics of
refuse impoundments, especially if the fine-grained
materials form the foundation for an overlying coarse
refuse embankment. The reason for the concern is that
the relatively high ratio of horizontal to vertical permea-
bility causes water to flow preferentially in a horizontal
direction through these materials, thereby possibly
transmitting high pore pressures to the toe of the
embankment. The deficiency described above was shown to
be a contributing cause in the 1972 failure of Dam No. 3 on
the Middle Fork of Buffalo Creek in West Virginia.
13.2.2.4.7 Compressibility—The compressibility
characteristics of the fine refuse materials were investi-
gated utilizing triaxial test results. Because of the
extremely low density and nonplastic characteristics of the
fine refuse materials, it is very difficult to prepare
samples for one-dimensional consolidation tests.
445
-------
The results of compressibility from the triaxial
tests are presented on Figure 13-19 in the form of axial
strain versus maximum effective principal stress for
samples consolidated under isotropic, as well as aniso-
tropic test conditions. A range of volumetric compression
of 2 to 4 percent was observed for the anisotropically
consolidated samples, as compared with approximately 6
percent for the isotropically consolidated samples at 100
psi maximum effective principle stress. The initial dry
densities for the above referenced triaxial samples varied
from 52 to 64 pcf. These data indicate that the fine-
grained materials are, in fact, less compressible than the
coarse-grained materials referenced in the previous section,
Again, it should be pointed out that the compressibility
characteristics of the fine-grained material are not
unusually high, and therefore these materials could be
safely used as construction materials if proper construc-
tion techniques and adequate protection against uplift and
piping potentials are incorporated in the design.
13.2.2.4.8 Shear strength—Shear strength parameters
of the fine refuse material were determined from laboratory
triaxial tests performed on 32 samples and are presented in
Figure 13-20 in the form of shear strength versus normal
stress for both effective and total stress. These samples
consisted entirely of undisturbed tube samples and were
tested under ICU test conditions.
The shear strength results presented in Figure 13-20
indicate that the angle of internal friction, based on
effective stresses, ranges from 37 to 40.5 degrees with
little or no indicated cohesion, and that the angle of
internal friction based on total stresses, is approximately
20 degrees with a cohesion intercept varying from 3 to 10
psi. The shear strength results of the fine refuse
446
-------
I -
2 -
4 -
RANGE OF DATA
OBSERVED FROM
Ko CONSOLIDATION
ON UNDISTURBED
TUBE SAMPLES
AVERAGE
COMPRESSIBILITY
FROM 32 ISOTROPICALLY
CONSOLIDATED TRIAXIAL
SAMPLES
MAXIMUM PRINCIPAL EFFECTIVE STRESS (Fj). pil
Source: W.A. Wahler & Associates
COMPRESSIBILITY CHARACTERISTICS
FINE COAL REFUSE
Figure 13-19
447
-------
I
10
O
CO
•33
in
THE SHEA* STREN6TH PARUETERS SHOW HEREON IERE OETERMINEO
FROM SI ICU TRI AXIAL SAMPLES.
-------
materials are remarkably consistent, considering the
range in dry densities tested and obviously reflect the
angularity observed in the fine-grained materials. As
stated previously, the shear strength characteristics of
the fine refuse materials also indicate a range in values
consistent with other construction materials. In
conclusion, although the low specific gravity and corres-
ponding dry unit weight under any conditions of placement
are not desirable physical properties for the fine-grained
materials, it is possible to utilize them for embankment
construction if these materials are properly confined or
ballasted in order to maintain their stability against
liquefaction and piping. Moreover, they may be essential
in construction of impermeable layers or zones for
impoundments.
13.2.2.5 Conclusions Regarding Physical Properties of
Coal Refuse Materials The physical properties of coal
refuse materials, which have been described and summarized
above, indicate that these materials exhibit many
characteristics that can be analyzed using conventional
soil mechanics theory. Although the amount of published
data available for this compilation is relatively small,
those data presented represent a range of physical
properties obtained from a number of different sites which
constitute a cross section of industry-wide practices. As
more sites are examined in detail, the amount of data
regarding the physical properties of coal waste will
increase and, when integrated with these data, will
measurably increase the validity of the conclusions
presented herein.
The coarse refuse material generally has adequate
shear strength, permeability and compressibility character-
istics consistent with other soil or rock construction
449
-------
materials which have been successfully used in the
construction of earth and rockfill dams. It is also
concluded that, using existing conventional earthmoving
and compaction equipment, dams or dumps utilizing coal
refuse as the major construction material can be construc-
ted to similar design standards which currently govern the
construction of earth or'rockfill dams, though there will
no doubt evolve significant differences as coal refuse
engineering develops.
There are several aspects of the material behavior
which require additional research, specifically, the
influence of degradation of these materials caused by
natural weathering or burning, and the effect of long
placement times. Needed research should be directed not
only toward an understanding of the physical aspects of
weathering and the resulting influence of the degradation
on the physical properties of the materials, but also on
the techniques used in the engineering analysis of the
stability and performance of refuse dams or dumps.
The fine-grained coal refuse exhibits unusually low
specific gravities as a result of unrecovered coal which
remains in the refuse slurry. However, these materials
exhibit relatively high shear strength characteristics
when compared to other fine-grained construction materials,
'and therefore, it is possible to utilize these materials
for embankment construction when ballasting or confinement
techniques are employed to maintain their stability against
liquefaction and piping. Indeed, in some ways coal refuse
materials may prove to be attractive as construction
materials in non-mine related engineering construction.
A properly constructed dump or impoundment must be
adequate in two principal ways: long term stability and
environmental acceptability. A stable refuse deposit may
not necessarily be environmentally acceptable. For
450
-------
example, highly acid water may drain in to a stream from
an otherwise "safe" embankment. On the other hand, a waste
deposit cannot be environmentally acceptable without also
having long term stability. A properly constructed refuse
deposit cannot be accomplished solely by good construction
techniques. If careful site selection procedures are not
used, if the concept of how the deposit will be formed and
will perform are not understood and if the design is not
properly carried out, sophisticated construction methods
will be totally wasted.
13.2.2.5.1 Unique characteristics of coal refuse—•
There are several unique characteristics of coal refuse
material. First and most important from a physical
properties standpoint, is the abnormally low specific
gravity of the fine refuse which averages about 1.5 (see
Table 13-3) as compared with an average soil value of 2.65.
As a result of the low specific gravity value, the result-
ing in-place dry density of the fine material, regardless
of its method of disposal, is also very low, with average
values of 50 to 70 pounds per cubic foot. The low density
of the fine wastes can create two deficiencies: 1) at low
density, the material cannot adequately resist the upward
flow of water from an impoundment and, therefore, if placed
in the foundation area without proper ballasting from
heavier materials, it can create serious problems of
internal erosion (piping), and 2) the low density may
result in the inability of the material to mobilize an
adequate effective stress to resist shearing forces. On
the other hand, the low density makes the highly impervious
fine material easy to transport, compared to ordinary soil.
The coarse coal refuse generally possesses a specific
gravity more like that of a natural soil material. The
coarse materials, however, contain flat, plate-like
451
-------
particles typical of slates and shales, which undergo
rapid weathering to clay after the material has been
deposited on the refuse pile. Also, if dumped in a loose
fashion, the coarse coal refuse will have a high porosity
(volume of voids) and tend to ignite by spontaneous
» '
combustion. The burning of the coarse refuse causes the
material to fuse together, thereby resulting in a net
volume reduction and the possible development of large
voids in the materials during the burning process. Coal
refuse and burned refuse, red dog, etc., also tend to
weather faster than most other alluvial or residual soils.
13.2.2.5.2 Conveyance and placement—As discussed
previously, it is the characteristics of the refuse that
often dictate disposal techniques. Disposal, as well as
construction, can be viewed as consisting of two opera-
tions—conveyance and placement. Coarse refuse is ,-
conveyed to the disposal site in a number of ways
including: hauling in trucks over access roads, in cars on
rails or on aerial tram systems, on conveyor belts, and
sometimes combinations of more than one system. At times,
coarse refuse is crushed and conveyed in a slurry with
fine refuse in pipelines. Fine refuse is almost always
conveyed in a slurry through pipelines to a disposal area,
normally an impoundment. All of these conveyance tech-
niques can still be used if they are used in the proper
manner and if other techniques are used in the placement
of at least some of the material so as to construct a
stable deposit.
Final placement of materials in the structural
elements—dams or retaining structures—will differ from
placement by simple dumping. In the dump, spreading will
usually be the only operation, whereas in the constructed
element, spreading, zoning and/or compaction will follow
placement.
452
-------
Placement or dumping of coarse refuse is largely
dictated by the conveyance method, although this is not a
necessary result if economics indicate that a second
handling of the material justifies using two methods to
place material where it is to go, rather than changing
entirely to another method. Truck hauling, which is
probably the most common conveyance method today, is rela-
tively flexible and all forms of dumps and retaining
elements for impoundments, discussed below, can be built
with flat slopes having some compaction with a minimum of
rehandling, if the trucks are carefully routed.
Aerial tram operations in the past have been the
least expensive conveyance method, but rehandling is
necessary to obtain compaction and relatively flat slopes.
Tram dumping is not as flexible as truck dumping, although
suitable embankments can be built with the tram system.
In practice, most aerial tram dumps become cross-valley
inpoundments and many are enormous in size. Aerial tram
operations will lose some of> their economic advantage if
material must be rehandled to construct flatter slopes and
to obtain a degree of compaction, although they can be
used to transport materials to the site for construction
of the retaining structure and to dump material in the
storage area behind the retaining structure if properly
planned as part of the system.
Conveyor belts almost always require rehandling of
the materials. In addition, conveyor systems are
relatively inflexible, although continuing development is
producing more portable systems. With the necessity of
constructing coal refuse embankments with improved stabil-
ity characteristics, relocation of materials may be
necessary for more systems and conveyor systems may come
into greater use.
453
-------
Rail handling systems were relatively common 30 to 50
years ago. They are the least flexible and are seldom used
today on a large scale. Slurry disposal in a reservoir,
where the solids can settle out or the water can be
filtered out through a stable filter-retention structure,
is and will reamin the most economical method of fine
refuse disposal at most plants.
13.2.3 Types of Refuse Deposits
In order to facilitate communication on an organized
basis, a classification system for coal refuse deposits,
as developed by W. A. Wahler and Associates, is included
as part of this manual.
A refuse dump is a permanent or long term accumulation
of mine, mill or plant refuse materials including low grade
coal, development rock and other products left over after
mining and processing of coal. A dump can be on or in
the earth and is not capable of impounding fluids. Dumps
have accumulated on a variety of land forms and assume
various shapes depending upon the original land forms, the
type of material disposed of and the equipment used for
disposal. Figure 13-21 portrays the simple dump forms
discussed.
13.2.3.1 Ridge Dumps -In some cases, coal refuse
materials have been dumped along ridge crests so that the
refuse materials reached their angle of repose on both
sides of the ridge. This type of dump is usually
constructed by dumping from cars off a rail system or by
use of dump trucks. Because the material falls downhill
to its angle of repose, a low margin of safety is devel-
oped; as the deposit grows, local or gross instability can
result, and sooner or later a stability condition
determined by the foundation materials will develop. This
454
-------
SIMPLE DUMP FORMS
TYPE OF DUMP GENERALIZED PLAN CROSS SECTION AB
LONGITUDINAL CROSS
SECTION CO
VALLEY-FILL TYPE I
-A
'-B
a b
CROSS-VALLEY TYPE II
rA1
a/a1 b/b
d e
-B1
SIDE-HILL TYPE III
/•
VIEW *
c d
VIEW
A
RIDGE TYPE IV
a be d
WASTE HEAP TYPE V
b c d
e f gh
\
W.A.WAHUR &ASSOCIAIES
Figure 13-21
455
-------
type of deposit does have certain elements that tend
toward stability because as material is dumped, natural
sorting takes place as the coarser material tends to roll
further, coming to rest near the base of the slope. The
resulting configuration provides stratification of
material parallel with the slopes and reasonable drainage
characteristics that will tend to keep water from building
up in the dump. If instability develops, treatment is
often difficult because usually the material is spread
thinly over a large area and a large amount of material
may need to be moved to improve its stability. This type
of dump is particularly susceptible to both long term
creeping failure and catastrophic failure.
13.2.3.2 Side-hill Dump A side-hill dump is similar
to a ridge dump except the deposit is on one side of a
ridge or hill. This type of dump is often constructed by
dumping off the side of a hill with mine cars or trucks,
although other techniques also are used. Stratification
of materials may also develop, as with the ridge method,
but may not be as pronounced because considerable dumping
may take place on the flat surface that develops at the
top of the deposit and the dump is usually thicker than
the ridge dumps. The side-hill dump is one of the most
common types of dumps. If the dump is unstable and the
mass of material involved is large and if it is located
adjacent to a flowing stream, it can slide across the
drainage course causing water storage behind the failed
portion of the dump with the potential for sudden release
of the stored waters when the "slide" dam is overtopped.
13.2.3.3 Cross-Valley Dump This type of dump, as
the name implies, is built across a valley or stream
course. The deposit is rare because in practice it usually
is capable of impounding liquids and becomes a cross-valley
456
-------
impoundment—which is very common. This type of dump is
usually very coarse-grained; therefore, the rate of
permeability is high and it is prevented from impounding
water because the outflow potential is equal to or greater
than the inflow potential. Without the capability of
impounding liquids, a cross-valley dump is generally a low
hazard deposit, although slopes can be unstable and subject
to sliding. It may also become an impoundment during a
severe storm condition, or if it becomes clogged by silt
and loses its permeability.
13.2.3.4 Valley Fill Dump When a cross-valley dump
or impoundment completely fills a valley and has no
capability of impounding liquids, it becomes a valley fill
dump. Valley fill dumps may be very large volume deposits;
they can be environmentally very acceptable, providing
erosion control measures are adequate. This type of fill
may be the most acceptable dump because it is in a form
that is relatively easily stabilized and abandoned; a large
flat surface can be made available for new uses after
refuse disposal ceases.
13.2.3.5 Waste Heap A waste heap, as the name
suggests, is a pile of refuse and is most often formed
where local terrain is relatively flat. It can be built
with a range of equipment types. Because it lacks the
capability to store liquids during its entire development,
it can be a low hazard type of deposit if its slopes are
adequately flat and graded so as to be stable. Aesthe-
tically, a waste heap could be poor unless extensive
revegetation and landscaping measures are taken.
13.2.3.6 Complex Dump -This category of dump is used
for a deposit that consists of more than one of the basic
shapes such as a complex side-hill cross-valley dump or
one which consists of so many combinations of other types
457
-------
as to defy description with a combination term. Many large
deposits have a very irregular shape and are best described
as "complex". Complex dumps develop when the mode of
operation has changed and disposal techniques are modified
as the dump is enlarged or when a very large amount of
material must be spread over an irregular landscape. Dumps
with a variety of forms may be difficult to analyze in an
engineering sense, because it is very difficult to deter-
mine material properties and distribution and to establish
with certainty which sections are most critical. Thus,
their hazard potential and environmental acceptability may
be difficult to evaluate with a high degree of assurance.
13.2.4 Construction Techniques Proposed for
Consideration
Many new construction techniques will be required to
reduce existing hazards and to minimize hazards at new
disposal sites. The current concern for environmental
effects will place a greater pressure on the coal industry
to develop new and acceptable procedures. In addition, new
engineering practices will have to be developed to deal
with some of the unusual properties of coal refuse. Both
research and active experience must be developed with
emphasis being placed on modification of existing deposits
so that they may be converted to other uses and on the
planning of new sites so that they can be readily abandoned
and permitting new uses of the disposal areas.
Much of the equipment presently used for coal refuse
disposal is adaptable to the application of new techniques.
Some equipment which is not commonly used by the coal
industry should be considered for wider use, including
earth compaction, moisture conditioning and screening
and grading equipment for material size selection.
458
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13.2.4.1 Modification of Existing Deposits
Described below, with an emphasis on construction tech-
niques, are some of the ways that existing deposits can
be made more acceptable. Use of modern engineering
analysis is pre-supposed as essential to modification of
construction practics-.
13.2.4.1.1 Active deposits—Present construction
practices encompass the use of most of the equipment and
procedures needed for modification of inadequate slopes
and graded embankments. For minor slope repairs and
grading, the bulldozer is the most adaptable. However,
bulldozers become inefficient when large quantities of
materials are moved relatively long distances, and
equipment not commonly used on dumps (such as scrapers,
loaders and trucks) but presently used elsewhere on the
mine property should be considered for large dump degrading
operations.
For spreading refuse dumped from trucks or tram lines,
bulldozers are effective, but scrapers should also be
considered. The spreading of refuse into layers should be
encouraged, even though little compaction is achieved,
because the exposure of refuse to air promotes oxidation
and reduced combustion potential upon burial. This is
particularly effective if active disposal areas can be
alternated, thus affording longer exposure. By alternating
disposal areas, equipment can be more easily routed across
embankment surfaces, thus achieving a further degree of
compaction.
Combustion control on an active deposit can begin with
some of the construction techniques described above.
Further, construction equipment is usually present on a
refuse disposal site, and often a widespread fire can be
prevented if the development of hot spots is noted, and
459
-------
immediate sealing and surficial wetting measures are
initiated at a smoldering location on the embankment.
13.2.4..1.2 inactive deposits—Some deposits are
operated on an occasional basis and some are abandoned for
a while to be reused when again convenient. These are
inactive deposits where the operation may begin again at
some unknown time. Full abandonment is not planned, but
operations have been suspended. Maintenance on such
deposits is difficult because they have not been protected
for long term self-maintenance, and yet are not kept up
by daily operation. A proper program of maintenance and
observation will be necessary to keep such deposits in
proper repair.
13.2.4.1.3 Abandoned deposits—Every effort should be
made to find suitable uses for abandoned coal refuse
disposal sites. A number of successful reclamation or
reuse projects are reported each year. Such an effort
will improve the image of the coal industry and in some
cases, may prove profitable to the company. Many old and
burned out refuse piles serve as quarries for red dog,
which is used for many purposes in the mining areas of
Appalachia. Care must be exercised in mining red dog
because several people are killed each year trying to mine
this material by excavating from the downhill toe. Because
the material is relatively stable, they are often able to
mine it until quite a high and steep cut is made. Failure
of the cut often comes suddenly and with lethal results.
Existing abandoned sites may require the construction
of some measures to minimize their hazards and improve
their environmental acceptability. The coal industry has,
for some years, been developing equipment and techniques
for seeding exposed slopes, particularly in strip mining
460
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operations. Many new procedures, some of them fairly
inexpensive, are becoming available through use of soil
chemistry and agronomy, whereby slopes can be graded or
treated with certain materials or chemicals that can
maximize revegetation efforts. Other construction proced-
ures such as rolling of slopes could be used to minimize
erosion. Many new erosion control techniques are presently
t
being developed through research and experimental
demonstrations.
13.2.4.2 Proposed Deposits Construction of new coal
refuse deposits can be most satisfactorily and economically
accomplished through adequate site selection, design and
construction techniques with an emphasis on an overall plan
leading to a suitably abandoned refuse facility. Earth dam
technology provides the basis for constructing zoned refuse
dumps. Since often the only construction material avail-
able is coal refuse, the material can be mechanically
graded so that materials of different gradations are made
available. Grizzlies and screens used in coal processing
can also be used for coal refuse grading. Many operations
use grading techniques for coal processing and, in some
cases, the grading used for processing could be utilized
for refuse disposal if the materials are not remixed prior
to disposal. Refuse dumps could then be constructed by
placing graded zones, internal drains and filters for
better stability characteristics.
Earth dam construction technology also offers
construction control procedures, whereby moisture condi-
tioning and testing procedures are used to determine
whether compaction techniques are effective and the desired
results are being achieved.
If relatively sophisticated techniques for embankment
construction are used, they should be adequately controlled
by surveying techniques that help monitor the position of
461
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the elements of the embankment as it is being constructed.
The performance of the embankment during construction and
later can also be monitored with instrumentation which is
installed during construction. Instrumentation equipment
and devices available include piezometers, surface and
subsurface settlement markers, slope indicators and others
with relatively sophisticated applications.
13.2.5 Types of Refuse Impoundments
An impoundment is a permanent or long term accumula-
tion of mine, mill or plant refuse, on or in the earth,
that is capable of impounding liquid. Impoundments
associated with coal refuse disposal have been used as
settling and filtering facilities and to store fine coal
refuse (sludge/slurry). Other coal refuse impoundments
serve as storage for coal processing plant water. Water
may also be stored without intent to store; this type of
facility is still termed an impoundment. Some impoundments
serve the dual purpose of acting both as settling ponds and
as water storage facilities. Even though a given facility
normally does not store liquids, it is an impoundment if
it has the potential to impound, that is, if during a
flood, water can build up in the retaining portion of the
facility.
The ponds that develop on most tailings deposits
serve multiple functions: to provide for collection and
storage of water in water-short areas, and to provide a
settling pond to remove suspended solids from the tailings
before the water is reclaimed or disposed.
These are the useful aspects of the ponds. There are
also a number of undesirable aspects to them, including the
following: 1) in the event of an embankment failure, the
ponds provide a quantity of liquid to enlarge the volume
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of material flowing downstream, thereby providing greater
erosion and carrying capacity to the material involved;
2) the more water involved in a flowing mass, the further
it can flow; 3) the pond provides a constant source of
water for saturation of the mass of tailings and, in many
cases, at least partial saturation of the containing
embankment. This increases the probability of liquefaction
failure under adverse conditions and lowers the strength
of the embankment below the phreatic surface even under
normal conditions; 4) the disposal capacity of a structure
is reduced by the volume required for the pond; 5) the
consolidation of the materials below the phreatic surface
is reduced due to the buoyant effect of water below the
surface of saturation (phreatic surface); and 6) the pond
provides a source of water that can infiltrate into the
ground, degrading naturally-occurring ground water.
Figure 13-22 displays the simple impoundment forms.
13.2.5.1 Cross Valley Impoundments This type of
impoundment is one of the most common types in regions
with steep terrain. Cross-valley impoundments are often
very large, and are particularly subject to flood hazard
problems because watersheds are often relatively large.
A very large precentage of the cross-valley impoundments
in the Appalachian region were considered inadequate in
1972 from the flood hazard standpoint. Many had inadequate
or no spillways or other flood bypass facilities. A
considerable number could have stored floods of record, but
the impounding element (dam) often would have been
structurally inadequate to store such a large volume of
water and would fail due to application of seepage forces
before it could be overtopped.
Cross-valley impoundments are constructed by several
methods. The most common methods are by dumping from
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TYPE OF IMPOUNDMENT
SIMPLE IMPOUNDMENT FORMS
GENERALIZED PLAN CROSS SECTION AB
LONGITUDINAL CROSS
SECTION CO
CROSS-VALLEY TYPE VII
a/a1 b'b
SIDE-HILL TYPE VII
x"
e (
DIKED POND TYPE
a be.
a1 b1
JIL
INCISED POND TYPE I
a b
u
Figure 13-22
W.A.WAHIER
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aerial tram cars, whereby the deposit rises with an
approximately horizontal or inclined crest across the
entire valley; or dumping by trucks, whereby the crest
level may be highly irregular along its length. Aerial
tram construction does not normally receive compaction of
any sort; truck-dumped fills receive some compaction by
equipment passage, particularly if some effort is made to
vary travel routes, but even this compaction is cosmetic
rather than real unless the lift thickness and moisture
content of the material is controlled and the equipment
haul carefully regulated.
13.2.5.2 Side-Hill Impoundments Another very common
type of impoundment normally used to store sludge is the
side-hill impoundment. Most of these facilities grew over
an older side-hill dump. Although side-hill impoundments
generally have relatively smaller drainage areas and thus
are not subject to. as great a flood threat as cross-valley
impoundments, they are often constructed with too thin and
too steep embankments, and are particularly subject to
piping failures and slope failures. Retaining embankments
for side-hill impoundments are usually constructed by
truck hauling and dumping. Some side-hill embankments and
attendant impoundments grow to enormous size, although
they seldom rival the size of the largest cross-valley
impoundments. One of the bad aspects of this type of
impoundment is that it often keeps a large portion of the
entire deposit saturated, thus lowering the general
stability of the structure, as well as the impoundment area
itself.
13.2.5.3 Diked Pond -Diked ponds are generally
only built where flat topography is available. They are
simply constructed by building a dike around the pond area.
Usually they are best adapted to truck operations. Where
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diked ponds are kept small, they usually do not pose great
hazards, but seldom do they aesthetically fit well into
the environment because of their long exposed dikes.
13.2.5.4 Incised Pond Incised ponds are least
subject to creation of potential hazards because they are
constructed below existing ground levels. Usually material
that is excavated from the pond area is used to construct
dikes. Therefore, in practice, an incised pond often
becomes a'combination of a diked pond and an incised pond.
Obviously, to obtain a large storage volume, a large
quantity of material would need to be excavated and
disposed of elsewhere to matintain a pond in a strictly
incised pond state.
13.2.6 Construction Techniques for Impoundments
Many of the construction techniques used prior to
Buffalo Creek were actually highly innovative and large
volumes of materials were moved at very low cost. The main
problem was that the practices involved only minimal
considerations of environmental adequacy and hazard
mitigation. Sometimes, this consideration could have
been achieved at very low cost and with satisfactory
results if consideration had been given at the proper time
to be effective.
A few valley fill embankments have been constructed
that have reasonably adequate drainage; these facilities
were revegetated and were available for other purposes as
land uses changed. Their hazard potential was usually
very low and confined to a very narrow and low-lying area.
Some operators mix coarse and fine refuse, normally
resulting in solid embankments and obviating the need for
an impoundment. Several variations of mixing operations
have been used. Some operators pipe slurry to a series of
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small ponds, the use of which is alternated so that
drainage takes place from previously used ponds. After
water has drained, the ponds are dipped and the partially
dried slurry trucked to a coarse refuse deposit. Another
method is to thicken and dewater the slurry at the plant.
The coarse and fine refuse are then mixed and carried to
the refuse deposit by truck or aerial tram. Still another
method used to obtain a degree of mixing is to form small
impoundments by excavating and diking on a coarse refuse
dump. Slurry is pumped into these small impoundments and
then covered with coarse refuse when the ponds are full,
thus at least partly mixing the refuse or at least dis-
persing the fine-grained material throughout the mass of .
the dump. Although some "mixing" operations produced high
hazard disposal sites, in general, hazards are considerably
lower at operations where one of the mixing procedures is
used.
A few operators achieve relatively low hazard disposal
dumps and impoundments, although they may be relatively
poor from an environmental standpoint and therefore diffi-
cult to abandon. For example, some construct many small
side-hill dumps rather than one or two large dumps or
impoundments. Although such practice is unsightly, hazards
can be kept to a minimum. Other operators construct very
large flat-sloped and wide-crested embankments that can
safely store very large floods.. Some of the resulting
impoundments have low hazard potentials, but these
facilities have almost always had severe environmental
problems and are most difficult to abandon adequately.
Thus, safety and environmental suitability must be planned
and achieved in concert, rather than as separate objectives
and operations. Unfortunately, just which combinations are
best has yet to be established. Several examples do exist
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where coal refuse deposits were graded to drain properly,
were revegetated, had long term stability and environmental
suitability and were made adequate for other uses.
Unfortunately, prior to the Buffalo Creek disaster, most
coal refuse disposal techniques were inadequate in some
way from the standpoint of hazard minimization as well as
environmental suitability.
Probably the most widespread hazardous practice
involved failure to recognize potential flood hazards;
where coal refuse embankments were constructed across
streams without providing adequate flood bypass facilities.
Disposal of coarse refuse at its angle of repose was
standard practice at most operations. Most embankments
were constructed this way regardless of the mdde of
conveyance or placement, the resulting form of the embank-
ment or the strength of the foundation.
Sometimes, during placement, coarser materials can
be concentrated near the downstream toe of an embankment
with a minimal change in construction procedure. This
should be encouraged, as better drainage characteristics
of the embankment will result and the stronger material
will be at the toe where it will do the most good.
Many coal refuse impoundments are enlarged by pushing
coarse material over the impounded sludge and increasing
the height of the embankment. This procedure may be
desirable if abandonment is close at hand, but such a
construction method must be understood and properly used,
recognizing the characteristics and limitations of the
materials utilized. If the strength characteristics of
the embankment are to be improved, downstream slopes need
to be flattened and weight increased at the toe by con-
struction of buttress fills.
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Often a relatively minor adjustment can be made in
sludge disposal to improve some impoundment's characteris-
tics. Sludge can be discharged near the face of the
embankment. Through natural sorting, the coarsest material
will settle near the embankment, and fines and water will
be driven into the upstream portion of the impoundment.
This procedure is especially to be recommended if the
upstream method of construction is to be used. Using a
multiple discharge system would further increase the
natural sorting process. Where coarse material is lacking,
cyclones can be used at the pond to separate materials on
the basis of size to assure placement of the coarser
material where its favorable structural characteristics
will be most useful and the fine material where it will
not constitute a hazard. Actually, such practices are the
first step in initiating systems whereby sludge is
mechanically sorted and used as a construction material in
a zoned embankment similar to techniques practiced in the
metals mining industry.
Strip mining practices produce some of the finest
rock excavations seen anywhere. This technology is avail-
able to the coal mining industry for construction of cuts
in rock for spillways where flood bypass facilities are
needed.
Even with the best practices and construction
techniques, occasionally an emergency can develop. If an
emergency plan is drawn up before an emergency develops,
construction equipment available on the site can be
effectively rallied to prevent or mitigate a disaster.
For example, if a boil forms on the face of an impoundment
dam or dike, it could develop into an embankment failure
unless quickly arrested and should, therefore, be
considered a serious condition. If equipment operators
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and plant personnel know what is expected, control
measures can be initiated, such as immediate placement of
reverse filters if material is available or placement of
rocky materials if filter materials are unavailable. Use
of piezometers to detect excess pore water pressure will
help prevent emergencies and allow for economical placement,
With careful planning and design, advantage can be
taken of how liquid or semi-liquid sludge relates to the
impounding embankment and sufficient area to avoid
constructing by the upstream method can be provided.
Additionally, starter dikes usually constructed of low
permeability materials can be incorporated into the
remaining embankment so that a high phreatic surface is
not created. Where a high phreatic surface will be created
by an impervious starter dike, the dam must be able to
withstand the pressure or consideration should be given to
deliberately designing and constructing a previous starter
dam which will preclude buildup of a high phreatic surface
in the dam or dump. In either event, the practice must be
to determine what is to be achieved and to achieve that
result rather than to follow a "standard" practice without
understanding its probable performance characteristics.
Many new impoundments can be planned so that spillway
construction costs can be minimized. Spillways can be
constructed at succeeding elevations as impoundments are
brought up. In some cases, disposal sites can be adapted
to a dual spillway concept which incorporates a service
spillway to carry unusual runoff. If the embankment is
properly constructed and can retain the design flood,
drainage ditches with their attendant problems can be
omitted.
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13.2.7 Surveillance, Maintenance and Abandonment
Coal waste dumps and impoundments must be maintained
or they will deteriorate and create safety or environmental
problems. When abandonment is contemplated, the deposits
must be prepared so that they will maintain themselves
in a manner similar to the adjacent natural materials or
they will cause lasting problems for everyone concerned.
It is desirable that the deposits maintain themselves as
compatible as possible with the rest of their environment—
neither degrading faster than the natural material in the
vicinity, nor being grossly more resistant to natural
processes than is the adjacent natural material.
Surveillance by direct and instrumental observation
is necessary to monitor the condition of deposits prior
to abandonment and to assure that maintenance is accom-
plished when needed and to assure that the maintenance is
adequate to control local problems before they develop
into serious matters. Surveillance also can monitor slope
or deposit degradation during operation so as to provide
a basis for estimating the type, nature and rate of
degradation to be used either for design of abandonment
measures or for concluding that abandonment can be made
without undue modification or trouble.
Routine surveillance and maintenance of operating
and inactive deposits is also necessary to detect and
minimize or remove hazards on both dumps and impoundments.
Waste deposits can only be maintained in a safe manner
through systematic and continuous monitoring of the deposit
conditions. A specific surveillance program has proven
to be considerably more effective than undefined haphazard
observation; moreover, only a skilled engineer understands
the mechanics of slope stability.
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Surveillance and maintenance are also required to
detect and prevent air pollution through dust and combus-
tion control and to evaluate and reevaluate construction
and dumping procedures in order to keep them effective,
efficient and economical, as well as keeping the deposits
safe and environmentally suitable.
In summary, the reason for establishment of routine
surveillance and maintenance procedures for coal refuse
deposits is largely to prevent hazardous practices or
conditions from developing or continuing. In other words,
they are preventative measures that, if properly planned,
will achieve the following goals:
prevent development of hazardous operations or
conditions;
control air and/or water pollution;
result in more effective and probably less
expensive refuse disposal (if costs of failures,
emergency repairs or required restructuring of
deposits are considered); and
incorporate, or lead to, an abandonment procedure
that will require little or no maintenance or
surveillance.
A routine maintenance program is required during the
active period of refuse disposal and during the period of
implementation of an abandonment plan. Ideally, after a
deposit is abandoned, no further maintenance is required.
However, in practice, maintenance should taper off as
slopes achieve a stable inclination, vegetative cover is
more permanently established, erosion controlled and the
deposit becomes a stable portion of the environment.
Nonroutine maintenance includes repairs or measures to
rectify unforeseen conditions such as a slope failure or
an outbreak of burning.
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It would be impractical to require an operator to
maintain a maintenance program after abandonment in most
cases. A more practical solution is to require abandonment
procedures that will need little maintenance and will
encourage establishment of other land uses such as home
and commerical sites, recreation, grazing, etc., that will
maintain stable conditions. Title to the land after
abandonment can be transferred to other ownerships and
other uses that should be responsible for the use and
condition of the land. The operator should be responsible
for creating a condition that is attractive to other land
uses.
Even with an enlightened approach to land reuse by
coal companies, a procedure for transferring surveillance
responsibilities to appropriate agencies after abandonment
may be needed. These agencies might include a number of
state agencies, such as: the Soil Conservation Service,
Public Health Service, etc. After an operator declares a
site abandoned and tentative approval is given, surveil-
lance should be continued by the operator long enough to
reasonably judge whether or not the abandonment procedure
is effective. The main point is that some vehicle is
needed to keep a watchful eye, even after abandonment of a
properly constructed refuse deposit.
13.2.7.1 Surveillance Surveillance techniques can be
separated into routine visual inspections and special site
monitoring incorporating instrumentation results and other
sophisticated monitoring techniques. Routine surveillance
should be performed by responsible company personnel, as
well as regulatory agency inspectors, who are familiar with
factors that cause hazardous and environmentally degrading
conditions. The big advantage of coal company inspections
is the day to day familiarity with site conditions as they
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develop. Also, there should be no need for more than
quarterly or bi-annual inspections by agency personnel,
if the facility is properly inspected, documented and
maintained by company personnel.
Special monitoring of a refuse deposit is required
when the deposit has been allowed to develop in an uncon-
trolled manner and/or where signs of instability or
environmental degradation are detected. Where such •
conditions exist, data from instrumentation arrays may be
required to adequately judge the condition of the deposit.
The selection and installation of instruments must be
performed by or under the supervision of a person experi-
enced in the techniques. This type of monitoring may have
a limited duration, if the structure is determined to be
performing satisfactorily and abandonment is complete.
However, other monitoring objectives such as water quality
or internal termperatures might require activities for
indefinite periods. Interpretation of the results of
specialized monitoring data usually requires sophisticated
techniques of analysis. For example, if the purpose of
instrumentation is to determine stability, the study must
be performed by an experienced and competent soils engineer,
Good surveillance and recording techniques can add to
the body of knowledge concerning the performance of
embankments and impoundments. The recorded performance
should be compared to the performance anticipated during
the design and analysis phase. The designer needs to know
how the facility is performing so he can formulate modifi-
cations if necessary. He also needs to protect his
client's investment, as well as his own reputation.
Sometimes embankments do not perform as intended, because
unforeseen difficulties can develop even though the design
was done according to current standards of practice. At
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other times, a facility is not constructed as intended
because of improper procedures which can be honest
mistakes. Further, conditions can change after the
facility is constructed through some natural or man-induced
process. Surveillance provides an element of protection
for everyone involved.
Legislation currently under consideration will most
probably broadly modify the Coal Mine Health and Safety
Law, and it may put abandonment under the proposed Mined
Area Reclamation Act. In any case, the coal companies
will be required, among other things, to perform strict
surveillance procedures on designated coal waste deposits.
Federal legislation has defined the responsibilities
of the Mining Enforcement and Safety Administration (MESA).
These responsibilities were formerly part of the U.S.
Bureau of Mines' activities. This authority, under the
1969 Federal Coal Mine Health and Safety Law charges MESA
with conducting routine surveillance inspections. If
conditions are not considered satisfactory by the District
MESA office, the Technical Support Centers, as well as
outside consultants, can be called upon to furnish
assistance. With this program hopefully hazard mitigation
can be achieved before major hazards can develop.
The 1972 National Dam Safety Act (P.L. 9L-367)
provides for a national dam inventory program to be
administered by the U.S. Corps of Engineers. Under this
porgram all dams, including mine refuse impoundments that
fall under legal definitions of a dam, will be surveyed.
Eventually, regular inspection and surveillance will be
initiated for control of potential hazards under the new
law. This may be accomplished directly by the U.S. Corps
of Engineers, the individual state or MESA.
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Surveillance by regulatory agencies has two basic
objectives: 1) to inspect facility conformance to an
acceptable plan and 2) to inspect facility performance.
An additional objective is to see that documentation of
the history of the deposit is maintained for later
reference if problems develop. Facility performance should
determine the need for changes in routine maintenance
procedures, for remedial work and, of course, for emergency
action if hazardous conditions develop.
13.2.7.2 Embankment Surveillance and Instrumentation
Surveillance as used herein is defined as the routine
visual inspection of a structure's performance as well as
the systematic collection, analysis and interpretation of
data obtained from various types of instruments installed
within a dam to aid in monitoring and evaluating the
performance of a structure. Routine surveillance should be
performed by responsible company personnel, as well as
regulatory agency inspectors who are familiar with factors
that cause hazardous and 'environmentally degrading condi-
tions. The big advantage of company inspections is the
day-to-day familiarity with site conditions as they develop.
Also, there should be no need for more than quarterly or
bi-annual inspections by agency personnel, if the facility
is properly inspected, documented and maintained by company
personnel.
Good surveillance and recording techniques can add to
the body of knowledge concerning the performance of
embankments and impoundments. The recorded performance
should be compared to the performance anticipated during
the design and analysis phase, or with a developed histori-
cal record of structure response. By using the knowledge
gained, a more precise, and hence more economical, design
may often be developed.
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Special monitoring of a tailings or leach dump
deposit is required where it was allowed to develop in an
uncontrolled manner and/or where signs of instability or
environmental degradation are detected. Where such
conditions exist, data from instrumentation arrays may be
required to adequately judge the condition of the deposit.
The selection and installation of instruments must be
performed by or under the supervision of a person experi-
enced in the techniques. Interpretation of the results of
specialized monitoring data usually requires sophisticated
analysis. For example, if the purpose of instrumentation
is to determine stability, the study must be performed by
an experienced, soils engineer.
13.2.7.2.1 Surface Monuments The installation
techniques for a monument included the setting of a 3- or
4-foot long section of rebar into a 12-inch diameter by
12-inch deep concrete collar. This method of installation
is relatively fast and inexpensive. Two men can easily
install 8 to 10 or more monuments in one day.
The total number of surface monuments will vary at
each site depending on the size of each dam and the method
of construction being used. For example, on any dam being
constructed by the upstream method, surface monuments
should be installed on each major bench at the quarter
points (distance between each monument equal to approxi-
mately 25 percent of the total berm length) if the berm
is less than 600 meters in length, the fifth points (20
percent of the total berm length between monuments) if the
berm length is between 600 meters and 1500 meters in
length, or at 300 meter stations if the berm length exceeds
1500 meters. If the dam is being constructed by the
downstream or centerline method however, the installation
of surface monuments cannot be completed until each time
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that a berm has been constructed which usually occurs near
the end of complete construction.
The time interval of readings of surface monuments for
tailings dams being constructed by peripheral discharge
methods can be scheduled to provide a maximum amount of
information. Survey readings should be scheduled such that
three or four sets can be obtained at equal time intervals
during deposition and then at monthly intervals after the
pond has been filled until it is observed that any major
horizontal and vertical movements due to pond filling have
ceased. It is convenient to plot the resulting data on
semi-logarithmic paper (one leg cycle by 70 divisions)
with the time in days from point of first filling as the
abscissa and settlement and/or horizontal movement in
tenths of foot as the ordinate. Long term monitoring data
for each monument should be plotted on an arithmetic grid
with settlement or horizontal movement yjj day of the year.
Significant data regarding the loading history, such as
day of first and final filling of a pond, should be super-
imposed on both graphs referenced above to aid in the
interpretation of resulting data.
13.2.7.2.2 Piezometers -Although open well piezo-
meters are often used in monitoring refuse dams, this
type of piezometer does not respond quickly enough to
changes in pore pressure to be used in tailings dams. The
use of pneumatic piezometers is preferred because of
their more rapid response time.
With regard to locating piezometers in the field, it
is better to select certain areas of the dam as test
sections and concentrate instrumentation efforts rather
than randomly installing a number of instruments throughout
the deposit. The number of test sections required will, of
course, vary depending on the size and type of the
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structure to be instrumented and the method of construction;
however, two test sections having three to six piezometers
each should be considered as a minimum. For tailings, dams
being constructed by the upstream method, a typical pattern
of piezometer location at each test section may consist
of the following:
Existing Tailings Dams—For existing tailings
dams, the piezometers should be installed on a
bench located at less than one-half the height
of the structure. The piezometers should be
placed using a down-hole technique at an approxi-
mate elevation corresponding to the one-third and
two-thirds height of the dam as measured from the
berm elevation to the foundation. This
installation technique should be repeated at
approximately 50-foot height intervals.
New Tailings Dams—The installation technique and
number of piezometers to be used in a new
structure is dependent on the construction method
to be used. For dams using a centerline or
downstream method, it may only be necessary to
install several piezometers in the downstream
half of the embankment in order to determine the
location of the phreatic surface with regard to
the foundation contact or drainage collection
system (if used). For new dams using an'upstream
method, a technique similar to that referenced
above for existing dams should be considered
except that at approximately 50-foot height
intervals, piezometers should be installed at a
depth of 10 and 30 feet in each of two holes
located about 100 and 200 feet inside the crest
of the dam. The above scheme will provide a more
thorough picture of pore pressures acting within
the exterior shell of the dam than that proposed
for existing dams.
13.2.7.2.3 Internal Movement Devices—The installation
of a device such as a slope indicator to monitor internal
movements within a tailings dam or leach dump can provide
valuable information regarding historical trends for a
given construction method. Although the costs associated
with installation and data collection are by no means
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insignificant, serious consideration should be given to
including at least one internal measurement device for
any major structure.
13.2.7.3 Maintenance Maintenance of active refuse
disposal sites is performed to provide reasonable assurance
that elements of a facility are functioning as intended.
This is especially important where modern, cost saving
design practices are used.
Access roads, necessary so that a site can be
approached routinely or during an emergency, are often
neglected. Roads that are difficult to pass over during
good weather can be expected to be impassable during bad
weather.
In the absence of vegetative slope cover, routine
grading and grooming of the deposit's slopes to drain
properly can prevent deep and extensive erosion, which in
itself can trigger a failure. Grading equipment should be
available so that regular grading can be accomplished.
Often no additional equipment to perform such maintenance
is required if careful and proper scheduling of work is
planned. One of the simplest grading techniques that can
minimize erosion on an embankment face is to grade the
crest surface so that water falling or accumulating on the
crest will drain away from the downstream face into the
impoundment.
Drainage ditches, spillways, drain pipes, decant
towers (all water conveyance facilities) need to receive
regular, routine maintenance inspections and periodic
maintenance cleaning to clear or prevent blockage by logs/
vegetation or sliding or eroded materials.
Occasionally, in spite of routine maintenance, exten-
sive erosion, landslides or some other unexpected situation
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may occur. These happenings need not be hazardous in
themselves, if prompt maintenance measures are then
initiated. A catastrophic failure often occurs after a
series of events takes place which is initially caused by
a relatively innocuous event.
Maintenance should be considered an integral part of
an active or even an inactive deposit. However, abandoned
sites cannot be economically maintained forever by a coal
operator. Converting a coal refuse deposit to another use
and conveying responsibility for any continuing maintenance
should be one of the incentives for properly abandoning a
refuse site.
13.2.7.4 Abandonment Perhaps the most difficult task
to properly plan for in advance is abandonment. The pri-
mary reason for this is the difficulty in predicting the
amount, type and rate of disposal, which can all change
rapidly with changes in technology and in economic and
market conditions.
Nevertheless, an abandonment scheme should be for
formulated as an integral part of the refuse deposit design.
The planning will save the coal industry money in several
ways. It establishes long term objectives to achieve and
makes abandonment a part of the overall mining system (with
the advantages of systems analysis); costly modifications
will not be required simply to abandon a site; and the time
required for final abandonment can be greatly reduced below
that which apparently otherwise may be required under
legislation currently under consideration. The latter can
be achieved by planning the growth of the deposit so that
some abandonment procedures, such as the establishment of
vegetation on slopes, can be started immediately on at
least part of the deposit.
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Abandonment of a dump may largely consist of grading the
deposit to drain adequately, and to initiate revegetation
measures for erosion control and aesthetic reasons. Many
new and surprisingly inexpensive techniques to control
erosion and to promote revegetation are under development.
Such measures not only promote good will toward the coal
operator but also can pay large returns in hazard mitiga-
tion.
Impoundments present more difficulties for planned
abandonment because of the large flat surface that may be
wet and inaccessible to equipment. If abandonment is
nearing, the pond surface can be gradually reduced by
grading from the peripheries. The pond surface should be
crowned so that surface runoff water drains toward the
margins of the pond area and is then carried past the
pond and retaining embankment. In some cases, low
permeability soil can be used on the surface to act as a
sealant to reduce both combustion potential and surface
infiltration of water and to provide a better material to
initiate revegetation.
More attention should be given by the industry to use
of the site after abandonment. In the long run, coal
companies may be overlooking valuable benefits that could
more than pay for land reclamation with good land-use
planning. Impoundments can be developed into safe recrea-
tional reservoirs with dump surfaces graded to support
shore side development. Also, some existing side-hill
dumps are large enough to support recreational areas.
Nearby communities may be in need of an impoundment for
water supply storage or, conceivably, for a sewage
treatment lagoon. Thus, in some cases, it may be safer
and offer other advantages to develop a reservoir rather
than to breach an impoundment. In many Appalachian states,
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where flat land is scarce and principally confined to
flood plains, refuse deposit surfaces and strip mine
benches may be excellent areas for home sites and commer-
cial building sites.
13.2.8 Embankment Construction Inspection
Today, more than ever, construction of embankments
requires a team effort. The ever-increasing escalation of
costs, the need for faster scheduling and the changes
occurring in the industry require full cooperation and
understanding among all the parties involved. Successful
production of the work under the traditional process
requires the utmost order and efficiency to obtain the
highest potential benefits. This goal can be reached only
through the understanding that all parties have a mutual
goal and are obligated to cooperate and perform to the best
of their ability in order to produce a satisfactory job.
This is difficult where many people of diverse backgrounds
are involved from beginning to end. Successful construc-
tion requires not only proper planning and design, it also
requires continuous checking, coordination, foresight, good
judgment and coordinated efforts by informed and qualified
individuals to accomplish the desired ends.
Inspection and control of embankment construction is
necessary to assure that the structure is completed in
accordance with design assumptions and requirements as set
forth in the plans and specifications, and to insure that
the construction costs are minimized. Effective execution
of this task requires that each member of the project staff
be aware of his place in the process, including his
responsibilities, authority and proper line of communica-
tion.
The site inspector's responsibilities are necessarily
variable in scope. The inspector must be completely
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familiar with the construction documents before commence-
ment of the work. He should have a close relationship to
the project designers and notify the designer of any
discrepancies observed, and request clarification for all
items not fully understood. The inspector must organize
and maintain a system of construction records such as:
a daily log book and daily report system,
progress reports on a systematic basis,
correspondence file,
payment file,
change order file,
shop drawing and sample submittal file,
substitutions file,
test and inspection results file and
site conference file.
The site inspector may be a full time employee of the
operator if the designer and regulatory agency can be
assured that he has the necessary knowledge, skill and
integrity to perform the inspection duties in a profes-
sional manner. However, an inspector employed by the
designer, who is highly trained and knowledgeable in the
field of construction inspection, would be preferable from
a technical standpoint. The assigned representative must
be given enough authority to make timely decisions on the
part of the operator. The operator should establish a
sufficient allowance in the project budget to provide for
the services of the construction inspector and/or the
construction inspection staff to control construction of
all structural elements of the disposal systems including
the necessary dams and retaining structures (usually made of
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refuse material). Limited.inspection is also needed
to control routine dumping to assure that the planned
operation is followed. Inspection will have to be full
time or part time depending upon the nature of the work
and how critical it is to the performance of the system
when completed.
13.2.8.1 Requirements of Plans and Specifications
The person in charge of performing the work, the inspector
checking the operation, as well as the operator, have the
responsibility to see that plans and specifications are
clear and that these documents are not misinterpreted.
Therefore, a thorough study of the construction documents
will be required by those performing the work and
inspections prior to commencement of construction. Any
errors, inconsistencies or omissions discovered must be
properly dealt with prior to construction, if possible, or
as soon as recognized if construction has commenced.
13.2.8.2 Verifications of Design Assumptions
Inspection and testing are possibly more important for
earth structures than most other works, because of
potentials for errors and deviations in actual materials
properties from those assumed in the design and the
potential seriousness of these deviations. By conducting
inspection and testing during fill placement, it will be
possible to check characteristics of the materials against
those assumed in the design. If the conformance is not
proper, the inspector must inform the person in charge of
the construction so that timely and proper modifications
can be made. If the refuse material from a particular
area will not meet specification requirements, it may be
necessary to seek out another source or possibly continue
placing the same material under a modified design. Any
design modification must be reported to and approved by
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the regulatory agency prior to commencement of the modified
construction work.
13.2.8.3 Site Inspector's Function_ Proper material
gradation is the utmost importance in zoned embankments
impounding sludge and water. Another important aspect is
to continually check material compaction by field density
tests. This will serve the constructor in his efforts to
attain the goal set for material strength and compression.
If such testing should indicate densities below those
assumed in the design, additional compactive effort,
possibly under changed moisture content, or by the use of
different compaction equipment, or a combination thereof,
may be required. If significantly greater densities are
being achieved than anticipated during design, it may be
possible, under certain limited conditions, to reduce
the compactive effort with a resulting savings in construc-
tion cost.
Proper recording of the construction operations and
results achieved will provide a basis for evaluating the
effectiveness and efficiency of the design, equipment and
procedures. The analysis of these evaluations could
result in design modifications, the selection of more
efficient equipment or a change in procedures which could
provide significant economical benefits. These economical
benefits might be realized on the project under construc-
tion and they may also be applicable to similar jobs in
the future.
The importance of a competent construction inspector
cannot be overemphasized. Good inspection can be worth
many times its cost in preventing errors and omissions of
construction that might impair the safety and durability
of the project and interfere with obtaining value for the
money invested. Good inspection demands the results
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needed but also relieves any unnecessary requirement or
impediment to the program that can be eliminated without
adverse results to the program. This means that improved
procedures can be used if they produce results compatible
with the design requirements and specifications.
The construction inspector's basic function is to
assure that the most reasonable compliance possible with
the construction specifications is achieved, consistent
with the design objectives. In addition, he serves as an
extra pair of eyes and should not be satisfied with merely
reporting mistakes in the work after they are made. He
can avoid misunderstandings by continually reviewing the
construction documents and working in conjunction with the
person in charge of construction. He should look ahead
and be fully acquainted with the construction documents
and all phases of the work. He can thus help avoid costly
and time-wasting mistakes and foresee bottlenecks due to
delayed delivery of material or improper scheduling of
the work. By promptly inspecting delivered materials and
observing the preparation and installation, he can prevent
costly tearout, replacement or redoing of the work. In
these and other ways, he can perform a real service to the
operator and designer. He thus becomes an important member
of the team needed to ensure a smooth-running construction
process and a safe and properly constructed project.
The construction inspector must be continually alert
to any condition that could impair the safety or function-
ing of the completed project: modifications to existing
structures, as well as construction of new projects, may
create temporarily oversteepened slopes, may loosen
temporary fills, may block streams, etc., and should
therefore be carefully observed and their potential for
creating a hazard judged.
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Note, however, that the site inspector is not
responsible for and should not, in most instances, under-
take responsibilities that are not a part of his services;
for example:
Telling the constructor how to construct the
work.
Guaranteeing that the work is constructed in
strict compliance with the contract documents.
(This is the responsibility of the constructor.)
Interpreting or ruling on the intent of the
construction documents.
Accepting the work or portions of it. The
designer is responsible for recommending this
to the operator.
Methods of operating equipment, including safety.
This is the constructor's and health and safety
regulatory agency's responsibility.
13.2.8.4 Regulatory Agency The regulatory agency
should receive and review a complete set of plans and
specifications, including corrections and amendments
thereto. These should be evaluated from the standpoint of
adequacy, completeness, construction safety and potential
for creation of future hazards. The approval of the plans
will be based on such review. Approval of the plans and
specifications for construction does not imply that the
completed project will not be disapproved if construction
is not performed in accordance with the plans and
specifications.
The regulatory agency should have its inspection staff
regularly check the construction operations. As a minimum,
the site should be visited when foundations are exposed
and prepared for placement of materials whenever a new
operation commences, and at regular intervals. During
these visits, inspectors should cover the entire site,
paying particular attention to the following:
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foundation conditions and preparation,
unusual site conditions not anticipated in the
design,
construction procedures,
methods of on-site inspection and control,
test frequencies, methods and results,
any hazardous conditions and
rate of progress.
A complete written record should be made of each
inspection and photographs should be taken of critical
items, as well as general site pictures and operations.
If any deficiencies are observed, they must be recorded
and reported to the operator's representative. It is the
operator's responsibility to devise a method of correcting
the deficiency. The regulatory agency must make certain
the deficiencies are corrected, but they cannot infringe
upon the operator's authority by dictating the method of
correction.
The methods of inspection and testing to be applied
during construction will depend to a considerable extent on
the provisions of the specifications. The inspection
techniques will be dictated by the type of specifications--
method specifications or performance specifications.
In Method Specifications, as they are defined herein,
the method of construction is outlined so that the construc-
tor may produce the finished product for the required
services throughout the desired period of time. It
therefore becomes necessary to observe construction to
ensure that the specified method is followed and periodi-
cally test the placed materials as the work progresses.
Obviously, method specifications impose greater burden on
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the designer; the product can only be as good as that
resulting from the specified method of construction. If an
inadequate product results, revised construction techniques
or design revisions will have to be made, as an adequate
product must be produced.
On the other hand, Performance Specifications allow
the constructor to carry out the construction work as he
chooses. However, he must arrive at the required product.
The adequacy of the product can be measured by tests, as
noted under Testing in the following section, similar to
those performed under conditions of method specifications.
13.2.8.4.1 If method specifications are used—
Operations—As the specifications outline the
thickness of material lifts, the number of
passes to be applied to each lift and the type
of compaction equipment to be used for compac-
tion, the inspector will have to check that
the constructor complies with these specifica-
tions. Furthermore, the constructor must use
the specified material type and place material
at the specified moisture content.
The latter may be difficult to comply with due to
weather conditions. Also, the available
materials may be somewhat different from those
anticipated. For these reasons, specifically,
modifications in the plans and specifications
may be required to obtain the desired end
product. The inspector should also assure that
the constructor complies with plans and
specifications as they relate to zoning in an
impoundment facility, the required final grades
and the like.
Testing—The primary tools for evaluating the
degree of compaction are earthwork control tests.
These are usually conducted in the laboratory
and define the maximum dry density and optimum
moisture content for the various laboratory
compaction methods. The optimum moisture
content is the amount of moisture which gives
the maximum density for a given compactive
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effort, or that which requires the least
compactive effort to achieve the highest degree
of compaction.
The test results will assist the inspector or
technicians, as well as the constructor, in
moisture conditioning during construction so
that the minimum compactive effort will suffice
to achieve the required compaction. In addition,
the control tests will serve the purpose of
evaluating whether the required fill compaction
is met. This in turn will indicate whether the
required strength of the placed material is as
specified.
Gradation tests to check actual drainage
characteristics of the materials used are also
required during construction. Some fine-grained
soils must have specific plasticity characteris-
tics. Atterberg Limits testing is generally
performed as a check to confirm these character-
istics.
13.2.8.4.2 If performance specifications are used—
Observations—As the constructor in this case
will not be guided as to how to perform the work,
but rather will have to guarantee that the
product is in compliance with requirements, he
may exercise his own judgment with respect to
construction procedures. The inspection
procedure will take a somewhat different form in
comparison to that required when method specifi-
cations are used. Checking of lift thickness of
the material placed and the number of passes
over each lift with the compaction equipment
will not be required. The inspector will,
however, be required to observe to see that the
general construction procedure is adequate and
that improper materials are not placed.
Extensive testing will, in this case, be required
to evaluate the consistency of the product with
plans and specifications. The tests will
indicate whether or not the product may perform
as anticipated and serve the intended purpose.
If negative results are indicated, removal of
the placed materials and replacement with
adequate materials will be required if material
gradations are improper, or the material would
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need reworking if, for example, moisture
conditioning is improper or compacted densities
are inadequate.
If the constructor consistently cannot produce
the required product by the construction
procedure he follows or other methods he may try,
the designer may be forced to modify the
specifications to a method specification.
However, this should be avoided, if at all
possible. It will be preferable that the
constructor modify his construction procedure
so that the required product can be produced.
Testing—Testing procedure should be similar to
those outlined above. The number of tests
would most likely have to be greater. Hence, a
greater number of technicians should be antici-
pated in comparison to those required when
method specifications are used.
13.2.8.5
It is always necessary to provide written correspondence
among the parties to fulfill the requirements of the
specification documents and/or regulatory agency require-
ments. In addition, the orderly construction of the work
requires distribution of information to many sources, and
this is best done in writing.
Correspondence is achieved through the use of letters,
memoranda, forms, reports, graphs, electronic devices,
etc. It is recommended that adequate documentation be
developed during the construction phase as a good practice
by all the parties. Many types of forms have been
developed, and it can be said that there is a form for any
need. Many organizations, individually or through
collaboration with other organizations, have developed
forms in an effort to standardize, but complete unanimity
as to type, contents, arrangement, etc., is not always
achieved.
On the proper forms, the inspector, having assured
proper compliance with plans and specifications, should
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provide confirmation to the interested parties. The
reports should contain a summary of the construction
procedure followed and the results of all field and
laboratory tests. These reports should be submitted on a
regular schedule to the regulatory agency.
The construction procedure and test results should be
reviewed with the design organization during construction.
This may be advantageous from the standpoint of initiating
timely and beneficial construction revisions to possibly
obtain the required result for less cost.
13.2.9 Embankment and Impoundment Recognition Summary
While it is true that many coal refuse dumps and
impoundments have been standing for considerable periods of
time, this should not be taken as any guarantee that a
given dump or impoundment is not unstable today. A slope
of an embankment may remain relatively undisturbed for
many years even though it is in a metastable condition;
that is, the factor of safety is only slightly greater than
one. Any change in the condition of the slope or its
material constituents can cause a concomitant change in its
stability. Figure 13-23 indicates the four basic elements
of interest in recognizing how changes in slope properties
can create stability hazards.
More detailed discussions of stability are available
elsewhere in this report, and in referenced literature.
The purpose of this section is to present a basic summary
of hazard causes and their recognition.
13.2.9.1 Conditions,, Affecting Stability From the
basic stability diagram (Figure 13-23), it can be seen
that any change in conditions in any one of the four areas
will affect the overall stability characteristics of the
embankment.
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LOADING AREA
(forces causing failure)
MATERIALS
AREA
(Properties affect stability)
forces resisting
failure)
TOE AREA
Figure 13-23
Basic Stability and Hazard Diagram
13.2.9.1.1 Loading area Additional loading can be
due to additional materials placed on the crest for dis-
posal, by heavy vehicles running on or near the crest, or
by the introduction of water due to seepage from ponding
on the upper surface of the embankment.
13.2.9.1.2 Toe area Removal of the material at the
toe, as is often done in excavating red dog products for
domestic and industrial use, can decrease the forces
resisting movement. Any other changes in the toe area
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caused by erosion of the surface, or by wave action from
a pond created immediately downstream, will also affect
this area. The practice of placing final clarification
ponds at the toes of coal refuse embankments (a fairly
common practice) is especially to be discouraged.
Excavation into the natural ground material in the
immediate vicinity of an embankment can also have resultant
effects, regardless of the purpose of the excavation.
13.2.9.1.3 Materials area Steepening of the slope
can be caused by red dog excavations, by road construction
on the face of the embankment or by surface erosion caused
by uncontrolled drainage on the slope face. In the case of
overtopping of an embankment, rapid erosion can take place
with resultant slope steepening.
Burning of the carbonaceous material in a coal refuse
dump or inpoundment can cause a reduction in volume and/or
the density. This may lead to cracking of the embankment
and the opening of seepage paths in to the materials area.
Explosions within burning banks have occurred upon the
introduction of water. However, all of the results of
burning are not adverse, since the shear strength of the
material may be ultimately increased and, where suffi-
ciently high temperatures occur, fusing of siliceous
materials may take place.
If sudden vibratory stresses are applied to the
materials in a relatively loose state, particularly if
they are saturated, a reduction in the effective stress
between the particles can take place, thus reducing the
shear strength. These vibratory stresses may result from
blasting, equipment operating on the dump, mining subsi-
dence, impact of dumped or sliding material and finally
from seismic shocks. In extreme cases, liquefaction of
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the material can result from this type of embankment
loading/ with resultant disastrous failures.
13.2.9.1.4 Foundation area Any increase in the
water level (the phreatic surface) within the foundation
or within the materials area can produce a reduction in
effective shear strength. This increase in water level,
or pore pressure, can be caused by surface water entering
the material, seepage water from the pond behind the
embankment, blockage of diversion culverts under or
within the embankment or the construction of an embankment
over an area with natural springs. Other factors might
include changes in permeability due to subsidence in the
area, filter materials becoming inoperative or ineffective
due to clogging and chemical or weathering changes of the
dump materials. Finally, in extreme temperature zones,
freezing of the downstream face may cause buildup of
seepage water because of the reduction in the permeability
of the exit area.
Piping, wherein material is removed by internal
erosion due to large quantities of water moving through the
foundation of the embankment, can form voids and affect
stability. Cracks due to burning, dump settlement or
areal subsidence can lead to piping failures, as can the
collapse of pipes or culverts within the embankment or
under the foundation area.
Rapid drawdown of the liquid retained behind an
embankment can cause abrupt changes in the seepage forces
involved in the upstream slope. Slopes aginst which
water has been retained for a considerable period will
have usually achieved seepage equilibrium and are more
susceptible to drawdown distress. Drawdown problems are
directly in proportion to the length of time the water
has been impounded and to the rate of drawdown, and
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inversely proportional to the permeability of the slope
materials.
13.2.9.2 Forms of Instability signs of distress or
instability in an embankment are usually related to the
factors discussed in this chapter. Many of the signs have
unique visible characteristics which can aid in reducing
the cause of the distress.
13.2.9.2.1 Rotational slips Movement of material
under unstable conditions within a dump or impoundment
frequently will be an approximate cylindrical or spherical
surface. Other movements may take noncircular forms such
as wedges, depending upon many factors including shear
strength, cohesive and frictional components, foundation
characteristics and stratification of the dumped material.
Rotational slipping usually exhibits tension cracks
at the top of the slope, accompnied by slumping or bulging
of the material near the toe of the slope. If the founda-
tion material is soil, the bulging may take place in the
natural ground beyond the toe. Rotational slips develop
at variable rates, and the signs may be visible for only
a short period of time before failure, or they may be
discernible over long, slow periods of deterioration.
13.2.9.2.2 Surface slips When dumps are constructed
with little or no compaction and the slope material is
essentially at the angle of repose, as is the case with
aerial tram dumping without additional equipment utiliza-
tion, sliding of shallow surface layers may take place in
a manner resembling sheet flow.
13.2.9.2.3 Flow-type slides Some granular refuse
materials may be dumped in a manner that results in a
material which will permit rearrangement of the granular
mass into a more dense state under stress conditions. If
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the material is saturated, the attempt to achieve the more
dense mass may be inhibited by the inability of the water
to escape from the mass rapidly enough, resulting in the
temporary suspension of the material in the water (excess
pore water pressure). The result is an unstable mass
resembling a viscous liquid which will move as a flow
slide.
A rapidly moving stream of water and water-borne
particles may result from intense surface runoff on a
slope, or from large piping volumes of water exiting
the mass. The suspension of solids will have a consistency
near 'that of a heavy mud, and the flows are termed mud
flows.
13.2.9.2.4 Creep When the materials that form an
embankment move at a slow, steady rate down and parallel
to the existing slope, the failure is known as creep.
Since the rate of movement of all the materials on the
slope may not be the same, the slide surface usually
will not remain parallel, but will either form waves
parallel to the crest length (when the upper portion moves
faster than the lower portion), or create tension cracks
parallel to and near the crest (when the lower portion
moves faster than the upper portion). When a slope is in
a metastable condition, a single action, such as cutting
an access road on or near the downstream toe of an
embankment, may initiate a creep failure. Should the
failure accelerate, either a flow-type or deep-seated
slide may develop.
13.2.9.2.5 Back-sapping When the flow of water on
the downstream face of an embankment is intermittent,
either due to piping or surface runoff, a concentrated
area of erosion may be produced which continues to progress
up the slope. Each subsequent movement of material will
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be of increasingly greater areal extent, and the resulting
physical evidence is termed back-sapping. Excavation of-
slope material on a continuing basis, again red dog mining
is a good example, can result in this type of slope
movement.
13.2.9.3 Factors Affecting Stability There are many
factors that can and will affect the stability of an
embankment. The majority of these factors are involved
with water in its various roles, embankment size (height
and other dimensions) and movement. A list of most of
the factors that affect embankment stability follows, and
must be included in any general data form being utilized
for coal refuse disposal evaluations:
size (height, width, volume),
slope steepness,
slumping, sloughing, sliding—is is surficial
or deep-seated?
cracks—are they parallel to embankment crest or
to the stream direction?
burning,
seepage—location, volume, is it carrying solids?
heavy downstream stream flow in dry weather,
elevation ;of free pond water with respect to
embankment features,
sink holes in impounded sludge surface,
boils in downstream toe area,
bank erosion,
embankment vegetation,
methods and location of current refuse disposal,
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abutment conditions—can a slide above the
embankment endanger it?
reservoir and watershed—can a slide (a seiche)
into the reservoir cause overtopping?
vegetation in the watershed,
has mining taken place beneath the area—
embankment, reservoir, etc.
These factors may be considered the most important
ones affecting visible signs of instability. However, they
are not the only factors of which one must be aware. The
following pertain to important factors concerned with more
specific areas such as appearance of the site, embankment
characteristics, sludge disposal procedures and water,
both as they relate to the embankment and to possible
flooding.
13.2.9.3.1 Appearance of the Site In general, it has
been found that the better the physical appearance of the
site and the disposal operation, the safer will be the faci-
lity. However, like most generalities, this is not always
true, and one must be able to distinguish between cosmetic
and real safety practices. For example:
Is the vegetation cleared from the pond and
embankment areas?
Is the disposal of the cleared material properly
controlled?
Is rubbish other than coal refuse being randomly
discarded?
Is the embankment burning?
Is the materials handling equipment in good
condition?
Is the embankment graded? Groomed? Revege-
tated?
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13.2.9.3.2 General Embankment Characteristics The
following items describing the characteristics of the
embankment should be noted by a competent inspector:
Is the embankment active, inactive or abandoned?
Is the embankment being enlarged? At what rate?
How? Where?
Is the material fine or coarse? Does the
material weather from coarse to fine?
Is the material being compacted? How? To what
degree?
How high is the embankment? What is the planned
final height?
How wide is the embankment? What is the top
(crest) width? What is the base width? What
are the slopes?
Is the embankment being raised by the upstream
method? The downstream method? Another method?
Is the embankment burning? Could the introduc-
tion of water cause an explosion? How much has
burned? What percent is red dog?
Is rubbish or other combustibles being deposited
with the refuse?
Are there cracks in the embankment? Where?
Direction of cracking?
Have there been slides on the surface? What
type? What extent?
Does the embankment retain water? Fine sludge?
Is there a pond now?
Is there a diversion pipe in or beneath the
embankment? Is the pipe clear or obstructed?
Can the water level be fully controlled?
Is there seepage present? Where? What volume?
Any coloration? Any solids being transported?
Does seepage pond on the slope?
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What is the embankment foundation? Was it
stripped or grubbed? Was a key trench or any
other barrier included in the foundation?
13.2.9.3.3 Sludge Disposal Considerations The
following items describing the characteristics of the
embankment should be noted by a competent inspector:
At what rate is sludge being deposited?
Continuously? Intermittently? Are there
periods when the pond dries out?
Where is the sludge being deposited? Upstream
or near embankment? Does the sludge deposition
erode the embankment?
What is the relationship between sludge, water
and available storage? How fast is available
storage being filled? Is there adequate
freeboard?
Is there evidence of piping in seepage water?
Are there boils on the face of the embankment?
Are there sink holes on the sludge surface?
13.2.9.3.4 Water as it Relates to Embankment Stability
Many, if not most, of the signs that indicate
embankment distress are associated in some way with either
subsurface or surface water in relation to the retaining
embankment.
The less the difference in elevation between any
seepage water on the downstream face and the
water level in the pond, the greater the cause
for concern. Try to relate how the embankment
has been constructed with the location of any
.seepage and visualize the phreatic line.
Remember that water emerging on the downstream
face may not be free, that is, no apparent
surface flow may be taking place.
On the downstream face are there:
Gross changes in color in a zone or on an
approximately horizontal line?
Vegetation differences in color or amount
in this zone or on this line?
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Variations in surface erosion? (Often
erosion is more pronounced below the zone
of saturation.)
Minor surface slides below the zone of
saturation?
If there is free water visible on the downstream
face:
Identify the point or points where the
water exits.
Estimate the quantity, temperature, quality
and clarity.
If the solids are being carried, estimate
the quantity and source.
Determine if the seepage flows are causing
erosion of the face.
Does the seepage flow pass beyond or is it
ponded on the surface?
Try to relate present or past seepage areas
to corresponding pond levels.
13.2.9.3.5 Water as it Relates to Flooding Since a
major rain storm and the resultant high storm runoff might
substantially increase any hazard associated with the
impoundment, the following factors should be determined:
How is the possible storage volume available?
How much of the possible storage volume is filled
with sludge?
How much of the possible storage volume is filled
with water?
What is the size of the watershed behind the
impoundment? Determine the runoff characteris-
tics of the watershed such as amount of
vegetation, infiltration potential, etc.
Have any provisions been made to carry runoff
around the impoundment? Are there diversion
ditches? Are they functional and maintained?
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Would they be blocked by slides during high
runoff?
Is there a spillway? How was .it constructed:
Open cut? Pipe? What is the relationship of
the spillway size to the estimated storm runoff?
Does the spillway discharge pass over the
embankment so as to erode the downstream slope?
How would a rise in the pond water level affect
the phreatic surface in the embankment? What
effect would such a rise have on the embankment
stability?
13.2.9.4 Hazards Rating System When what appears to
be a potentially disastrous condition at a refuse disposal
site is identified or suspected, an Emergency Hazard Rating
System is useful on which to base a degree of reaction and
to facilitate communication. The setting of a numerical
hazard rating on a site under study, while desirable from
an administrative and field inspector's point of view, is
a difficult, if not impossible, procedure. Since a
single deficiency can be the cause for a site to require
immediate review or action, a combination of minor
deficiencies from several rating elements does not
necessarily best indicate that a site is safe or unsafe.
A simple direct system is best for this purpose, and
an Emergency Hazard Rating System based along the following
lines can be utilized:
I. High Potential for Loss of Life
II. High Potential for Loss of Property
III. Low Potential for Loss of Life or Property
IV. No Potential for Loss of Life or Property
It is also desirable to have a rating system for less
immediate situations. In this context, a more complex
system can be developed. For example, an evaluation
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system can be established based on the physical conditions
of the deposit and the consequences of failure. The
condition rating can be obtained from the results of the
inspector's observations and data from the Basic Data
Forms (see Appendix A), such as size, storage volume,
etc. The consequences of failure ratings can be assessed
from the determination of the characteristics of the area
that could be affected by a failure. Table 13-4 outlines
one possible approach.
Table 13-4
Possible Consequences of Embankment Failure
Consequences of Failure
I. High potential for loss
of life and property
II. High potential for loss
of property
III. Low potential for loss
IV. No potential for loss
Condition
A. Major Deficiencies^
Impoundment
B. Major Deficiencies-
Dump
C. Minor Deficiencies
D. No deficiencies
The priority for review can be determined by combining
the relative importance of each of the two categories shown
in Table 13-4 and placing the combined ratings in descend-
ing order of importance as follows:
1. IA High potential for loss of life and
property; Major Deficiencies—Impoundment
2. IB High potential for loss of life and
property; Major Deficiencies—Dump
3. IIA High potential for loss of property; Major
Deficiencies—Impoundment
505
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4. IIB High potential for loss of property; Major
Deficiencies—Dump
5. 1C High potential for loss of life and
property; Minor Deficiencies
6. IIIA Low potential for loss; Major Deficiencies--
Impoundment
7. IIC High potential for loss of property; Minor
Deficiencies
8. IIIB Low potential for loss; Major Deficiencies-
Dump
9. ID High potential for loss of life and
property; No Deficiencies
10. IIIC Low potential for loss; Major Deficiencies
11. IVA No potential for loss; Major Deficiencies—
Impoundment
12. IID High potential for loss of property; No
Deficiencies
13. IVB No potential for loss; Major Deficiencies—
Dump
14. HID Low potential for loss; No Deficiencies
15. IVC No potential for loss; Minor Deficiencies
16. IVD No potential for loss; No Deficiencies
These ratings, and the basis for them, are not
intended to be stringent or constraining. They cannot be,
due to the nonspecific nature of the contents of the
evaluation. They are only intended as a preliminary
method upon which an order of priority for review of
refuse deposits can be based. A certain degree of flexi-
bility must be allowed because of the many variables
involved.
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13.2.10 Control of Mine Drainage from Coal Refuse
Deposits
As documented in EPA publication EPA-R2-73-230,
Control of Mine Drainage from Coal Mine Mineral Wastes,
Z. V. Kosowski, 1973, with proper planning and diligent
attention to basic details, relatively basic and simple
technology can be applied to the stabilization of most
coal mine mineral waste deposits with the subsequent
control of pollution and with a minimal impact on the
environment. Recognizing that the indicated report was
based on what was accomplished at one site, in one
location under a given set of conditions and that it should
not be construed as applicable to every individual situa-
tion, the following conclusions may be applied as axioms:
1. Acid runoff from refuse piles can be controlled
by covering the mineral wastes with soil,
establishing a vegetative cover and providing
adequate drainage to minimize erosion.
2. No significant differences were observed in acid
formation rates from the three individual test
plots covered with a nominal 1 foot, 2 feet or
3 feet of soil. However, it was more difficult
to uniformly place 1 foot of soil on the steeper
slopes.
3. Slurry lagoons containing the fine coal rejects
can be stabilized and the air pollution problem
controlled by either a vegetative cover estab-
lished directly on the mineral wastes without
soil or by the application of a chemical
stabilizer. Chemical stabilization is only a
temporary measure, and vegetative covers should
be the permanent solution to slurry lagoons.
The primary ojective of the demonstration project
conducted in cooperation with the Midwestern Division of
Consolidation Coal Company was to establish water and air
pollution abatement techniques which would provide an
essentially permanent stabilization, would require a
507
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minimum of maintenance and be aesthetically pleasing. The
basic principle adopted consisted of sealing the coal refuse
with a suitable cover to minimize the movement of water
and air into the refuse, thereby reducing or eliminating
the subsequent formation of acid, siltation, erosion or
fugitive aerosol emissions.
During the course of the project, the primary atten-
tion was directed towards the vegetative covers that could
be established and maintained with conventional agriculture
techniques and machinery. Since the surface of the refuse
disposal site was highly acidic (pH < 3) and could not by
itself support a vegetative cover, a suitable thickness of
clean earth was placed on the graded refuse pile and a
vegetative cover established thereon.
The mechanism of control originally postualted was
as follows:
1. The cover should be sufficiently impermeable to
decrease or stop water movement into the pile.
When this occurs, the products of oxidized
pyrite will not be washed away during periods
of rainfall, and fresh pyrite surfaces will not
be exposed. Further, a vegetative cover can
function as a water-consuming layer through the
principles of evapotranspiration, thus further
reducing the quantity of water entering the
interior of the pile.
2. The cover should be sufficiently impermeable to
oxygen to act as an efficient diffusion barrier.
Since oxygen (and water) must be continuously
present to support the pyrite oxidation reaction,
any material effectively separating the pyrite
from the atmosphere will cause the oxidation
reaction to either slow down or cease completely.
The characteristics of the cover then control the
oxidation reaction. In addition, the cover can
function as an oxygen-consuming layer. A
vegetative cover such as grass may build up
enough organic matter in the soil to support high
rates of aerobic bacterial activity. Such a
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layer can be effective in removing oxygen from
the soil atmosphere before it reaches the zone
of pyrite oxidation.
3. The above phenomena, either singly or in combina-
tion, should reduce the acid formation over a
period of time to negligible quantities.
The question of soil thickness in covering refuse
piles appears to be a controversial one. From a technical
standpoint, it is difficult to justify topsoil cover
greater than one foot thickness on a properly graded refuse
pile with adequate drainage control. Anything greater than
one foot can be regarded as safety factor to camouflage
improper grading and inadequate drainage. Of course, as
the graded slope increases beyond the aforementioned, the
difficulty of applying a nominal one foot of soil cover
increases correspondingly.
When clean earth is to be used to cover a refuse
pile as a prelude to establishing a permanent vegetative
cover, a sufficient number of soil samples should be
taken from the borrow area and analyzed for soil nutrients.
If a substantial depth of soil is to be moved from the
borrow area, core samples to the ultimate depth of the
borrow area should be taken and analyzed. Submitting
samples from surface scrapings can lead to erroneous
results, since rarely will the soil from the surface of a
borrow area find its way on the surface of the covered
refuse pile. The areas to be seeded should be divided
into smaller segments that can be limed, fertilized,
seeded and mulched promptly (e.g., within one or two days)
after the earth cover has been applied. Otherwise heavy
rains inevitably occur that lead to erosion and gulleys
and the necessity of redoing what has already been done.
Regarding specifics of fertilizers, lime requirements and
seed mixtures for grass covers, it is almost impossible to
509
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recommend any specifics because soils, climatology and
ultimate land use vary so widely. Drainage and pH control
of the soil are basic to the establishment of most
vegetative covers. Native grasses with a good past
performance record should be favored. Fertilizer applica-
tion should be made on the basis of the grass seed selected.
It is good practice to include in the grass seed mixture
at least one species of native legumes. A complete and
comprehensive listing of grass seed mixtures with
recommended fertilizer requirements and other valuable
information is available in the Department of Agriculture
"Grass, The Yearbook of Agriculture, 1948", available from
the Superintendent of Documents. Additionally, the benefits
of surface, treatment with an alkali such as limestone, lime,
fly ash or waste alkaline products (prior to covering with
earth) have not been adequately demonstrated. It is
recognized that even if effectively sealed, most refuse
deposits would continue to generate acid for several years.
It is therefore paramount that after sealing and during
establishment of the vegetative cover, the most important
parameter, i.e., the one given the next highest priority,
is erosion and drainage control. Everything else should be
considered as being secondary. Uncontrolled runoff damages
everything. Reducing the velocity and controlling the flow
of runoff can make the greatest single contribution in
ultimately abating pollution from refuse piles. A variety
of measures are available to control runoff. These include
proper grading, subsurface drains, diversion ditches,
terraces and vegetative covers.
It is not possible to lay down any hard and fast
rules as to a specific slope for the grading operations, as
every situation is different. Slopes greater than 1:2
are more difficult (but not impossible) to construct and
maintain with conventional earth-moving equipment.
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Techniques developed in the interstate highway program
and in major construction projects can be directly appli-
cable to refuse pile grading. Equipment such as graders,
tractors, bulldozers and earth-carrying vehicles is readily
available, and improvements in capacity, reliability and
efficiency are continuously being made by the manufacturers.
When the slopes exceed the capability of conventional
earth-moving equipment, a variety of other equipment is
available such as draglines and shovels and, under extreme
conditions, manual labor. Bench terracing is another
practical alternative that may be adopted for extremely
steep and/or long slopes. The top of the pile should be
formed into a dished plateau or bowl. All peaks and
ridges should be graded toward.the low point in the bowl
since this helps to reduce the amount of runoff and surface
water draining along the sides of the pile with a
corresponding reduction of erosion and gullying. Adequate
drainage from the bottom of the dished area is a must and
can best be accomplished by open ditches made and
maintained out of a variety of inexpensive materials—wood
troughs, concrete-lined channels or large-diameter metal or
plastic pipe cut lengthwise and firmly anchored into the
ground. Grass sod should not be overlooked as an effective
alternative. The total cost of grass sod may not be as
high as other alternatives. The collection and treatment
of the drainage will be addressed in Section 13.2.12,
Preparation Plant Process Water. Slurry lagoons, because
of their unique physical and chemical characteristics,
should be treated differently. Grading is usually neither
required nor desired. However, drainage control is
extremely important because of the unstable nature of the
slurry material. Adequate drainage facilities and erosion
control should be provided to reduce the velocity and
control the flow of runoff. Where gulleys already exist,
511
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these can be filled with bales of straw, slurry, clean
earth or other inert fill. When a permanent vegetative
cover is planned, careful attention to opening the dikes
at strategic points must be provided since most slurry
lagoons are completely enclosed during active operations.
This will require the construction and maintenance of
permanent, stable structures at the outlet of the lagoons
to control the runoff and direct it into the nearest stream.
Otherwise, channeling and gullying will take place and
slurry will be deposited in the nearest stream.
The establishment of a permanent grass cover directly
on the slurry lagoons, without the use of topsoil, is a
relatively simple procedure provided a vehicle is obtained
that will traverse the lagoons with a load. The procedure
consists of soil testing, limestone application, fertilizer
addition, grass seed sowing and mulching with straw. For
purposes of establishing grass covers, slurry lagoons can
be classified as free-draining, very poor-grade soils.
Drought-resistant species and legumes native to the area
should be considered for use in any grass seed mixture for
slurry lagoons. Straw is the preferred mulch for both the
refuse pile and the slurry lagoons since the soils are
essentially barren of any humus. Chemical stabilization of
slurry lagoons is only a temporary measure because of
solubility, abradability and nonrenewable nature of the
chemical agent. Because chemical stabilization does
provide almost instantaneous stabilization and dust
suppression, it does present an attractive temporary option.
However, permanent vegetative covers should be the ultimate
solution for slurry lagoons.
512
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13.2.11 Closed Water Circuit
The possibility that regulations will be developed
stating that for "coal preparation plants, zero discharge
systems will be required" have forced the coal industry
to actively pursue 100% closed water circuits. The current
need for more and cleaner energy is in direct conflict with
the goal to completely close the preparation plant water
circuit. To produce a higher quality product (less sulfur
and ash at a respectable Btu recovery), the coal must be
crushed finer and finer to liberate the entrained
impurities. The smaller the coal particles become, the
more complicated the coal washing process becomes. The
direct result is that much greater washing capacities must
be incorporated into the preparation plant which in turn
means an increase in the use of water.
For a typical 1200 ton per hour plant, a waste water
treatment facility that can handle approximately 800 gpm
of slurry containing as much as 75 tph of solids with 75%
of the particles being 200 mesh or finer and with an ash
content in excess of 50% must be available. The problem
in closing a water system of this magnitude is how to treat
the waste material effectively and economically to produce
a product that is 100% acceptable in terms of water effluent
standards while at the same time creating a handleable
solids material.
The techniques of dewatering and drying of the clean
coal and refuse products has been addressed in detail in
Chapter 8; however, the final water clarification problems
begin as the water effluent from the dewatering and drying
process leave the actual process flow. The dilemma in
closing a plant water circuit begins with the thickener
design. Depending upon size consist and ash content, the
engineer has to choose the type of thickener that not only
513
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provides low initial capital investment but also a low
operating cost. The final decision of what type to install
is usually dictated by the projected thickener feed size
consist and quantity of waste water to be processed.
13.2.11.1 Thickeners and/or Clarifiers Thickeners
are usually circular tanks, 40 to 200 feet in diameter.
The slurry is introduced into the thickener at the center.
The clarified overflow is removed at the outside edge of
the top rim of the tank. As the slurry flows from the
center to the rim, the solids settle to the bottom of the
tank, where they are scraped to the center of the tank by
plows. In one type, there is a slowly revolving vertical
shaft in the center of the tank with a number of radial
arms attached to the shaft, parallel to and a short distance
above the tank bottom with vertical plates (plows) set
obliquely to the arm and attached to the bottom of the arm.
The plows direct the settled solids to the center of the
tank where they are removed as tank underflow. Any degree
of removal of solids which can be settled can be attained
in a thickener by the proper correlation of capacity and
dimensions. Figure 13-24 shows a steel tank flat bottom
thickener and a concrete tank sloping bottom thickener.
Most thickeners are installed with some type of arm
lifting device, particularly in applications involving
flotation tailings. The fine clays may occasionally tend
to gel, which retards the flow to the withdrawal point
causing a ring or "donut" formation. If the arms can be
raised and lowered, the ring can usually be broken up.
Also, there is always the possibility of coarse coal enter-
ing the thickener due to flotation cell malfunction or to
a screen break. A lifting device may permit continuous
operation without excessive torque on the mechanism by
lifting out of the coarse settled solids and lowering the
rakes as these solids are removed.
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9TUL rum rur torn*
wl Tank Bottom and Sid*
coKcnm rum SLOPING BOTTCH
~ Dlach.rga Con«
Figure 13-24
Thickener Tank Designs
Feedwells in the tank center are designed to quiet the
incoming flow prior to entry into the tank proper. There
are many designs and modifications which dissipate the high
inlet velocity head by imparting a high degree of small
eddy formation and, preferably, a radially uniform distri-
bution of flow into the tank. A poorly designed feedwell
will result in jets or streaming beneath the feedwell skirt
which can create undue turbulence in the thickener
resulting in an overflow containing unsettled solids.
515
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Pumping systems for withdrawing the underflow have
typically been installed by means of a tunnel system
beneath the thickener. The pump may be located at the
center of the thickener in an enlarged section of the
tunnel, or the pump suction piping may lead through the
tunnel to a pump house adjacent to the tank. Figure 13-25
depicts the standard Tunnel System.
TOP vim
Walkway.
Drive H»d
Con* Scraper
Discharge Cont
WS=f 1 r-
•oQ&i-; i
•"•&^* r-ff-
!^.^a-.
'**• '-I1*
•VV^.%-
Underflow
Discharge
Figure 13-25
Standard Tunnel Solids Withdrawl System
To accelerate the settling of the solids, chemicals
for flocculation are usually added. Many types of
chemicals are used including inorganic types, such as
alum, lime, iron salt and sulfuric acid and organic types
such as pre-gelatinized starch and synthetic organic
polymers.
Another form of separating equipment is the Drag Tank,
which is a relatively long horizontal tank of rectangular
516
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or trapezoidal- cross-section, with one end inclined. The
suspension of solids in water is fed in at the end
opposite the inclined end and the overflow is removed from
the top near the latter end. As the water flows through
the tank, some of the solids settle to the bottom. A flight
conveyor is provided for the removal of the settled solids.
The path of the conveyor is along the horizontal bottom, up
the inclined end, returning over the top and vertically
downward and finally turning and connecting with the hori-
zontal portion. Dewatering takes place after the conveyor
leaves the water and passes up the incline. The amount of
dewatering depends on the length of the incline and the
conveyor speed. The conveyor speed should be approximately
the horizontal velocity of the suspension through the tank.
In passing through a Drag Tank the solids in a feed
suspension settle by an amount which depends upon the time
available for settling and the terminal velocity of the
solids. The time for settling is a function of the cross-
sectional area of the tank, the volume flowing and the
distance between the inlet and overflow.
The EIS clarifier, a high capacity sedimentation
device, built by the Enviro-Clear Company, was introduced
commercially quite recently. Adapted from the sugar beet
processing industry, the EIS clarifier combines the attri-
butes of modern synthetic flocculants with bottom feed of
the effluent into previously formed zone of flocculated
solids. The newly flocculated feed, moving through this
bed, causes additional agglomeration of the floccules
present. In effect, the resident agglomerated solids zone
acts as a filter bed, thus eliminating the free-settling
zone normally present in conventional thickeners. The line
of demarcation between the agglomerated solids and the
effluent is very sharp and hence provides an interface for
517
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control of solids withdrawal. The capacity of this unit
is said to be 8 to 10 times greater than for conventional
thickeners.
* First installation of this thickener was made at the
Grapevine Preparation Plant of U.S. Steel Corporation;
there, a 35 foot in diameter EIS thickener is used to
clarify approximately 3,850 gpm of feed containing an
average of 3.7% solids. The overflow contained approxi-
mately 240 ppm of solids, and the underflow contained
approximately 34% solids. Flocculant was added at the
concentration of 6 ppm.
After determining the thickener design, the engineer
is then faced with the real problemt What is to be done
with the solids being pumped out of the thickener
underflow? The viable alternatives are:
impoundment,
underground stowage,
mechanical dewatering,
thermal drying,
incineration or
chemical mixing.
13.2.11.2 Impoundment The techniques of impoundment
construction and use have been discussed in detail in
Section 13.2.2 through 13.2.9. However, under new laws,
the use of impoundments or slurry ponds is being closely
regulated and the building of slurry ponds has become a
very expensive and time-consuming process, assuming the
operator is fortunate enough to be issued a permit, is
blessed with a certain amount of good dam building material,
has the appropriate land and terrain and has a good report
from the geomechanical analysis of the proposed site. In
518
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mining areas where these favorable conditions exist, an
impoundment is still the least expensive alternative in
closing a water circuit.
Impoundment makes closing a plant water circuit sound
easy, but for those operators not fortunate enough to have
building materials or good lying land readily available,
the project becomes somewhat more complicated and expensive,
particularly where the operator has to dynamite and exca-
vate an area for the impoundment and then line the entire
pond. At this point, the economics become such that other
alternatives of closing a plant circuit must be
investigated.
13.2.11.3 Underground Stowage The second easiest
way to discard the thickener underflow or fine waste is
to pump it back underground. Some operators employ this
process on a limited basis and many are initiating a
pre-planned mining program at newer deep mines to possibly
allow for future pumping of waste slurry into old workings.
Underground stowage necessitates better planning between
the mining and preparation groups in order to insure proper
mine support, barrier pillars and life expectancy of the
void. This system of disposal will lag many years behind
actual mining because entries must be driven to the dip
and all equipment recovered before stowage can proceed.
Along this same line, abandoned mines make an excellent
area in which to pump if the operator is assured of
relatively large number of voids in the mine, is positive
that all the barriers between mines are still intact and
has determined that the stowage area will not become a
source of acid mine drainage or otherwise impact the
ground water.
13.2.11.4 Mechanical Dewatering The accepted methods
of dewatering a thickener underflow fall into the category
519
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of mechanical dewatering which includes filters, centri-
fuges and high speed screening devices. Historically,
each method has had various problems. Disc filters have
been hampered by a poor release and low tonnage when
filtering refuse. This situation has been helped by the
use of different construction materials for filter bags
and the "snap blow" process frequently found in dewatering
other mineral concentrates. Drum filters have been used
on a limited basis in the coal industry. Other industries,
particularly sewage plants, are using the drum filters
with much success on minus 10 micron particles.
Pressure filters have been used in Europe for a number
of years, but have not been installed in this country yet
(U.S. Steel may be in a prototype stage). This type of
filter has been found to produce a relatively dry filter
cake and a solid free effluent. Table 13-5 compares the
important pressure filter elements versus the same elements
in a disc filter needed to produce 30 tons per hour of dry
solids from a 30% solids feed.
Table 13-5
Pressure Filter Use vs Disc Filter Use
Feed
Dry Tons per Hour
Cake Moisture
Capital
Pressure Filter
30% solids
30
20 - 23%
$2.4 million
Disc Filter
30% solids
30
35 - 40%
$200,000
Source: M. J. Gregory, Manager-Preparation
North American Coal Corporation, Powhatan Point, Ohio
520
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It is obvious from Table 13-5 that although the pressure
filter produces a much more desirable cake, the capital
cost is appreciably higher than a disc filter. The operat-
ing costs are also higher because of the semi-automatic
cyclical nature of the filter which requires nearly
constant attendance by an operator.
EIMCO Envirotech is testing a horizontal belt type
vacuum filter with steam as a filter aid. In laboratory
tests, reportedly, they were able to dewater 200 to 400
pounds of feed per hour per square foot of active filter
area to a final moisture content of 7 or 8% on cleaned
coal samples. It is possible that the horizontal belt
type filter may be applied to fine refuse solids.
The conventional BIRD centrifuge has been modified
recently in an attempt to close the preparation plant
water circuit. The solid bowl centrifuge for coal refuse
dewatering has typically been a low tonnage machine whose
effluent usually contains a fair amount of extremely fine
solids which were recirculated to the thickener and
sometimes resulted in a solids buildup. By increasing the
pool depth and moving the solids concurrently, a test model
of the new "H" series centrifuge has proven a solids
recovery in excess of 99.9%. The unit is now available
in 15 and 30 ton per hour sizes (see Figure 8-11).
When handling the refuse material described earlier,
mechanical dewatering devices cannot process as much
tonnage as they could if a cleaner material, i.e., one
with a majority of the suspended solids settled out of
solution, was being dewatered. Both filters and centri-
fuges are affected in a similar manner. To help increase
the capacity of these units, polymeric flocculants are
used to accelerate the settling of the suspended solids.
Polymeric flocculants have a proven ability as dewatering
521
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aids, but are relatively expensive and must, therefore,
be selected and applied carefully. Typically, flocculants
applied to materials analyzing 70% minus 200 mesh producing
filter cakes between 30 and 40% moisture have ranged in
costs from $0.005 to $0.35 per ton of refuse solids
recovered: The higher the ash content of the refuse, the
higher the chemical additive costs. Additionally, as
demonstrated in Figure 13-26, the addition of more and
more polymer does not insure an increase in solids
recovery and an accompanying dryer product from the
dewatering mechanism (in this case a filter). In fact, if
too much polymer is added, the risk of producing a filter
cake that holds more moisture is created and the resulting
cake becomes excessively difficult to handle. Consequently,
it is advisable to operate a thickener at a less than
optimum condition when using polymer in order to compen-
sate for the frequent swings in refuse tonnage being
treated.
Most mechanical dewatering processes involving refuse
material are menaced with one major problem if they
achieve near success in closing the water circuit—the
dewatered material contains a high percentage of moisture
and is usually difficult to handle. The solids are in a
semi-fluid state and cause problems on haul roads and
particularly in disposal areas. Heavy equipment is unable
to maneuver over the material and an attempt to mix coarse
refuse with this material results in the entire refuse pile
becoming unstable. Segregated disposal is also difficult
because the area containing the fine refuse material is
useless for additional dumping or grading until further
dewatering is accomplished by evaporation or natural
runoff, generating unwanted fugitive water emissions.
Because of this problem, further dewatering may be neces-
sary to accomplish the objective of a closed water circuit.
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W
04
O ^
K H
OJN
IB
w
o
u
o
w
$6.00
5.00
4.00
3.00
2.00
1.00
0
5 10 15 20 25 30
PPM SUPERFLOC 214
10 15 20
PPM SUPERFLOC 214
Figure 13-26
Impact of Polymer on Solids Recovery
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13.2.11.5 Thermal Drying or Self-Incineration There
are numerous approaches to dewatering refuse tailings by
thermal methods, all of which require technical and econo-
mic assessment on a case-by-case basis. Both direct heat
and indirect head contact systems have been studied
experimentally. Generally it is felt that neither the
direct nor indirect dryer system has strong potential
application in successfully dewatering fine refuse slurry
as generally both produce a product that though dry, still
lacks characteristics attractive for subsequent handling
and final disposal and because of the tremendous added
capital and operating cost of a secondary thermal dryer and
particulate recovery system. However, North American Coal
Corporation has successfully thermally dried a fine refuse
material containing:
Moisture 29.3%
Dry Solids 70.7%
Ash 35.72%
Heating Value 8,700 Btu/lb.
Total Dry Solids
using the Denver Holo-Flite Conveyor. The unit was
successful in drying the material, but is more economically
feasible drying fine coal than fine refuse.
Thermal approaches to dewatering are available,
however, that are uniquely different than that of just
drying the material. These systems are the fluid-bed
calcining agglomerator and the multiple-hearth incinerator.
Pilot plant tests have indicated that when a mechanically
dewatered refuse slurry of 35 to 45% moisture is introduced
to a multiple-hearth incinerator and ignited, it can
consume itself and generate enough heat to pre-heat and
ignite the incoming feed. According to John Anderson of
U.S. Steel Corporation, solids having over 50% ash and less
524
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I
than 9000 Btu per pound (dry) have successfully burned
autogenously. M. J. Gregory of North American Coal Corpo-
ration found that self-incineration was maintained on a
refuse material containing the following:
Moisture 31.0%
Dry Solids 69.0%
Volatiles 15.0%
Fixed Carbon 34.2%
Ash 51.0%
Heating Value 6,000 Btu/lb.
Total Dry Solids
The multiple-hearth incinerator or roaster has been
utilized in the mineral industry for many years. It
requires only enough oxygen through a very low-velocity
air supply to provide a slightly excess oxygen mixture
for partial carbon combustion and to offset radiation
losses. The product produced is in the form of a highly
stable, non-weathering semi-clinker bearing a size consist
of about 90% 2" x 1/8". Experimental results indicate
that stack emission particulate limits and S02 emission
limits are satisfactorily attainable. Throughput rates on
a wet basis appear to be in the range of 18-24 lbs./ft.2
per hour.
The fluid-bed agglomerator is a modification of a
fluid-bed drying unit in which refuse slurry is injected •
into a previously heated fluidized bed of inert material.
If the refuse slurry contains sufficient Btu's and is
metered in at a balanced rate within a range of about 37
to 44% solids, maintenance of heat availability for
autogenous combustion of the refuse solids can occur on a
steady-state basis without auxiliary fuel needs. As the
system stabilizes and the carbon is consumed, ash pellets
are formed and are released for disposal from the
525
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fluidized bed at a system controlled rate and in a stable,
non-weathering form.
13.2.11.6 Chemical Additives The possibility of
adding chemicals to the waste water slurry which will
produce a residual solid of substantial strength while
allowing the process water to be freed and recirculated to
the plant as makeup water is being investigated by the
Dravo Corporation. It appears from initial investigative
reports that this process may have merit particularly
where mechanical mechanisms cannot handle 100% of the plant
load.
Addition of the solids reagent to a refuse slurry
amenable to the treatment results in a chemical bond
between the slurry solids and the water associated with
the slurry. A cementation reaction occurs with the solids
taking on a set within a relatively short time and develop-
ing an increasing strength. Most of the water combines
reactively with the solids. Following the set time period,
the solids become readily handleable if further transport
is desired or if allowed to remain at the initial location
of deposit, will set progressively harder to the point of
being absolutely stable and non-weathering. This would
permit repetitive disposal-set cycles upon previously
stabilized deposits.
Provided the nature and characteristics of the refuse
solids permit reaction with the reagent (and many coal
refuse slimes do) the treatment requires little capital
expenditure/ however it has been determined that often up
to 10% by weight of reagent must be added to the dry
solids in the slurry to effect results. Furthermore, it
has been determined that the higher the percent solids
concentration of the slurry being treated, the faster and
526
-------
.more successful the set reaction, and the smaller the
•&
percent of reagent that must be added. The minimum solids
*
concentration level for effective cementation appears to be
about 35% with significant improvement in results at 40%
4 »
solids.
13.2.12 Preparation Plant Process Water
The water used in coal preparation operations is
usually obtained from one or more of the following sources:
rivers and streams,
mine water and wells,
public supplies,
captured surface runoff water and
treated water from slurry ponds or collection
ponds for fugitive water effluent from waste
deposits or plant sites
In some instances, coal preparation plants may be located
near a stream in which case the use of this water is highly
advantageous primarily because pumping costs are low and no
treatment is generally required. Waste water from coking
plants located near preparation plants has been used in
some fine coal circuit installations. Other preparation
facilities, located near power plants, may utilize the
water from the power plant cooling circuit—although this
water may be higher in temperature than surrounding rivers
and streams, it is generally less costly and possesses
distinct advantages in several preparation processes.
Usually, clean streams void of contaminants from sewage,
organic matter or acid drainage are acceptable as sources
of water. In most cases, however, the water is obtained
at the lowest cost including any treatment that is neces-
sary.
527
-------
The consumption of water per ton of coal treated in the
individual plant varies over a wide range depending upon
availability of local water, cost of the water, the type of
cleaning process, whether or not the plant water cirucit is
open or closed, the quality of the feed water and the
requirements of effluent treatment prior to release of the
water to a natural drainage system if the plant water
circuit is open. Although appreciable savings of water can
be achieved by the addition of plant water clarification
systems, the amount of water required for coal preparation
has been increasing over the years, particularly due to the
increasing complexity of preparation process.
The water quality has some effect on all the opera-
tions in preparation plants. Changes in water quality
during coal preparation occur as fine coal and mineral
particles, such as clays, become suspended in plant process
waters. These particles vary in size from 28 mesh to
colloidal dimensions. It has generally been agreed upon
by water scientists that particles from 0.1 to 74 microns
determine the properties of water. It has also been deter-
mined that concentrations of solid matter in preparation
plant wash water should be less than 5 percent or between
30 to 110 grams per liter. The primary disadvantages of
using water charged with solids during the coal cleaning
process are:
The solids cause excessive wear, chiefly on
pumps and cyclones by erosion.
The solids may alter the density of the cleaning
process (bath) and may increase the viscosities
of the heavy media used in the separation process.
The solid laden waters do not adequately rinse
the washed products.
The rapid increase of froth flotation has introduced
a new aspect of water treatment requirements. As indicated
528
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in Chapter 7, most cleaning processes in use in preparation
plants do an acceptable job down to 48 mesh. A large
percentage of the 48 mesh to 100 mesh fractions of coal
now produced is being sent to the settling ponds or
recovered in closed water systems as refuse. The trend is
that more operations are resorting to froth flotation to
recover the fine size coal, with the result being that, in
addition to the suspended solids in the process water, the
action of dissolved minerals or salts in various promoting
agents that are added to enhance flotation, flocculation
and filtration significantly effect the properties of the
process water. Also, run-of-mine coal contains varying
amounts of minerals and soluble salts. Some minerals and
salts such as chlorides and sulfates of the alkalais and
alkaline earth metals dissolve easily in water. Under
certain circumstances, the salts will significantly change
the pH of the circulating water. For example, calcite,
aragonite and dolmite are slightly soluble to the extent
of 14 parts per million in pure water at 25° C. The
influence of additional salts present in solution increases
the solubility of carbonates. Thus, sodium cholride in
concentrations of up to 7% by weight can increase the solu-
bility of calcite by 3.8 grams per liter. However, if the
water contains carbon dioxide, or if any additional acid
is present, the carbonate will neutralize the acid to a
value proportional to its concentration. Soluble clays
may also exhibit basic properties. It is conceivable for
pyrite, marcasite and other sulfites that are normally
insoluble in water, to oxidize and to form ferrous sulfate
and sulfuric acid. The oxidation of iron sulfite has
serious effects on pH, normally lowering it to between 2.8
and 5. Iron sulfate is sometimes used as an agent to
promote the action of flocculant electrolites. The
529
-------
addition of salts, through either artificial or natural
means will increase the conductivity of the solution.
A variety of processes, both physical and chemical,
are being used to clarify plant process water, depending
upon the undesirable characteristics of the water. If the
process water consists only of suspended solids, typical of
many cleaning plants, settling ponds or lagoons are
constructed near the active operation. Water is directed
into the ponds and the solids are allowed to settle. The
ponds should be large enough to handle peak flows expected
at the site. The clear effluent is decanted and recycled
back into the cleaning plant, or it is discharged into
the nearest natural drainage facility.
Large ponds can be constructed which can be used for
many years, or several smaller ponds can be constructed
in parallel. If the large pond is used, provisions should
be made to cover the solids in the pond after it is
filled and abandoned, otherwise the dry and fine solids can
be picked up by high winds and create an air pollution
problem. Covering the solids with clean earth, fertilizing
and planting grass is an effective way of completing the
job.
If land space for ponds is not available, thickeners
are generally used. The overflow from the thickener is
usually recycled back into the cleaning plant, but if
sufficiently cleaned, it can be discharged into the streams.
Underflow from the thickener is pumped to a black water
pond for final disposal.
When the process water consists only of suspended
solids and acids, with little or no iron, acid neutraliza-
tion operations can be used with finely ground limestone
(calcium carbonate). However, the reaction product is
530
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gypsum (calcium sulfate) which coats the limestone and
makes it unreactive. Therefore, when using limestone to
neutralize non-iron containing process water or collected
fugitive acid mine drainage, the use of a rotary tub-type
mixer is recommended to grind away the gypsum that sticks
to the limestone. The neutralized water is then directed
to a settling pond or lagoon for solid separation, with
the effluent discharging into the stream or recycled into
the cleaning plant.
If the process water or collected site fugitive water
contains large amounts of dissolved iron, two types of
treatment plants can be used depending upon whether the
water is acid or alkaline. If the water is alkaline, it
is simply aerated (either neutral or forced) in a large
lagoon. Upon aeration, the dissolved iron changes into an
insoluble form called ferric hydroxide, or yellow boy, and
it can be separated from the water in a settling pond.
Although the process itself is simple, high volumes
of iron-containing sludge are formed. The sludge can
present serious disposal problems, particularly in
mountainous areas where land suitable for ponds is scarce.
Under certain favorable conditions, sludge has been pumped
back underground into worked out sections of an active mine
or into properly sealed abandoned mines. The sludge may
also be transferred into worked out strip pits and covered
with spoils and topsoil during the normal reclamation of
surface mining operations.
If the water is acidic, a chemical treatment plant
may be built adjacent to the preparation plant. Hydrated
lime (calcium hydroxide) or quick lime (CaO) is added to
the acid water, followed by a forced aeration. The water
then passes into a pond where sludge settled out to the
bottom and a clear overflow is discharged into the stream
or returned to the plant.
531
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The use of lime generally leaves the water saturated
with dissolved salts which, in many instances, tend to
scale equipment and piping, leading to high maintenance
and repair costs. Other alkali chemicals such as caustic
soda (sodium hydroxide) or soda ash (sodium carbonate) will
decrease scaling but have found only limited application
due to their high cost.
13.2.13 Coal Waste Disposal Summary
As is portrayed in Figure 13-27 and discussed in
detail in Sections 13.2.1 through 13.2.12, there are a
multitude of techniques for handling coal refuse disposal
and its associated pollution problems. The costs of coal
refuse disposal and the associated stabilization of the
refuse deposits will vary widely and will depend upon the
quantity of refuse, the size of the refuse, the availa-
bility and type of disposal site, the amount of potential
pollutants present, the ease of control of the pollutants
and varying meteorological conditions. Every solid refuse
stream or associated water pollution problem is a special
case and must be thoroughly investigated before the
treatment process is selected.
13.3 AIR POLLUTION CONTROL
As stated in Chapter 12, the air pollution from coal
preparation plants relates primarily to particulate
emissions, including fugitive dust from the transportation,
such as haul-roads, and from the bulk handling of coal and
coal waste products as well as the particulate emissions
from the thermal drying processes and from uncontrolled
refuse pile fires. There is also additional air pollution
in the form of gaseous emissions from the thermal drying
processes.
5.32
-------
COARSE
COAL
PLANT
FINE
COAL
PLANT
DEWATERING
SCREENS
Plus 3/8" Refuse
Minus 28 M
3/8" x
28M Refuse
8 Water
DEWATERING SCREENS
OR
PIER
3/8" x 28M Refuse
MINUS 28M
COAL
RECOVERY
Minus 28M
Undersize
Filtrate
Minus 28M Tailings
THICKENING
•-T
Underflow ,
Minus 28M I
I-----*
.1 , ,
FILTERS |
„.-, 1
(Underflow
.Minus 28M
SUMP
'I
I
Plus 28M Refuse
Minus 28M
I
Filter Cake
REFUSE BIN
AT PLANT
I . 1
iMinus 28M
I Refuse Slurry
r_ J. ,
I PUMPS '
L- r - J
rr
Belt Conveyor J
L —
SLURRY
I Aerial Tramway
REFUSE '
| --- J --- '
j DISTRIBUTION BY
' TRUCK OR
I SCRAPER LOADER
«. -1 — -
I
POND
1 ------ 1
1
I
r •—' 1
| HAUL & DISTRIBUTE .
|BY TRUCK OR SCRAPER
. LOADER J
"II I
REFUSE . Clear Water to SOre
_ ^jj | or"~t
-------
13.3.1 Summary of Proposed Air Quality Standards
Standards of performance have been promulgated for new
coal preparation plants. The standard limits emissions of
particulates (including visible emissions) from the
following sources, which are the affected facilities:
Thermal dryers, pneumatic coal cleaning equipment (air
tables), coal processing and conveying equipment (including
breakers and crushers), screening (classifying) equipment,
coal storage, coal transfer points and coal loading facili-
ties.
The standards apply at the point(s) where undiluted
gases are discharged from the air pollution control
system or from the affected facility if no air pollution
control system is utilized. The standards for these
sources would limit particulate emissions to the atmosphere
as follows:
Particulate Matter from Thermal Dryers
1. No more than 0.070 gram per dry standard
cubic meter (0.031 grain per dry standard
cubic foot).
2. Less than 20 percent opacity.
Particulate Matter from Other Affected Facilities
Less than 20 percent opacity.
Most states do not have specific air pollution
limitations for coal preparation plants but rather make
them subject to a general process weight regulation. Three
states do, however, have codes applicable exclusively to
coal preparation plants. The most restrictive is 0.02
gr/dscf for thermal dryers—this regulation does, however,
permit exit concentrations to increase with decreasing
capacity. In addition, all coal producing states have a
general visible emission restriction which limits all
sources to a maximum 20 percent opacity.
534
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13.3.1.1 Selection of Pollutants for Control Emissions
from thermal dryers include combustion products from the
coal-fired furnace, but these quantities of emissions are
a small fraction of the particulates entrained by the flue
gases passing through the fluidized bed of coal. During
testing operations preceding the publication of EPA
450/2-74-021af initial emission samples from thermal dryers
were analyzed for products of combustion and heavy metals.
Table 13-6 presents the results of the analyses of combustion
products. The table permits a comparison with the standards
of performance for coal-fired power plants.
Both NO and S09 emissions were found below the perfor-
X 4b
mance standards required of new coal-fired power plants.
Admittedly, the dryers tested were processing (and using as
fuel) low-sulfur coal. However, only 12 percent of all
thermally dried coal is greater than 2 percent sulfur,
primarily because thermal drying of lower quality coals is
not generally an economically attractive alternative.
Table 13-6
Combustion Product Emissions from
Well-Controlled Thermal Dryers
Coal-Fired
Emission rate Power Plant
Pollutant Concentration, ppm lb/(Btu x 10 ) lb/(Btu x 10 )
NO 40 to 70 0.39 to 0.68
x
SO 0 to 11.2 0 to 0.09
x
HC (as methane) 20 to 100 0.07 to 0.35
CO 50 30
Standards of Performance for Fossil-Fuel-Fired Steam
Generators as Promulgated in 40 CFR 60.40
0.70
1.20
—
Source: EPA Publication EPA 450/2-74-021a
535
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Finally the wet scrubbers used to control particulate
emissions from thermal dryers also appear to control SO-
emissions. The two dryers tested emitted S02 at 0-10
percent of the levels expected, based on firing rate and
fuel sulfur content.
13.3.2 Applying Dust Collection Equipment to the
Coal Cleaning Process
A coal preparation plant has several incentives
besides the law to strive for good dust control, including
the elimination of a nuisance and providing more pleasant
working conditions, the reduction of maintenance cost and
lost time due to unnecessary machine wear, the elimination
of a major safety hazard and the recovery of a salable
product.
Whenever a preparation plant utilizes thermal drying,
dry screening, crushing, transfer points or silo storage,
there should be some type of dust collection equipment to
capture and remove the dust.
The non-stack fugitive emissions from coal utilization
processes occur from operations in which coal or its
products are stored, transferred or reacted. Wind-blown
dust from coal piles is one example of a fugitive emission,
as is smoke from a burning coal waste disposal pile.
Run-of-mine coal is transported (by truck, conveyor or
railroad car) to the preparation plant. This transport
and the subsequent transfer to a storage pile or silo are
the first opportunities for fugitive emissions (coal dust).
Open pile storage can be subject to wind-blown coal
dust losses. If the pile is dry and the locale is subject
to high and frequent winds and pile working, the losses can
be serious. Unless outdoor conveyors and transfer points
are enclosed, coal being transferred to the crushers and
536
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screeners can be a source of wind-blown coal dust. The
final transfer of coal to the rail cars or trucks, and its
subsequent transport to the user, is the last potential source
of fugitive emissions.
There are three principal methods available for the
measurement of fugitive emissions. Each is designed to
sample a specific class of fugitive emission. The methods
and their applications can be summarized as follows:
Quasi-Stack—A duct and fan are fitted to capture
the emissions from a local source. Standard
stack sampling methods are used for analysis.
Point sources such as storage silo leaks,
materials pouring, etc. are readily measured
using this sampling method.
Roof Monitor—A vent or roof monitor used for
venting of a building or enclosure is- used as an
air sample source. Ambient air monitoring
equipment is used to measure the emission flux
through the monitor or vent. Flow measurements
using anemometers can thereby be used to develop
mass emission rates for the building or enclosure.
This is therefore best used for indoor, tightly
enclosed structure fugitive sources.
Upwind-Downwind—A meteorologically based sampling
array is used to determine the emission flux into
and out of an open source. A three-dimensional
network of ambient air samplers upwind and
downwind of the source serves to determine
pollutant concentrations. Knowledge of wind
speed and direction allows determination of the
emission rate. There is a need in many cases
to also run tracer tests and use diffusion
modeling to refine the results. The environmental
impact of outdoor and multipoint complex sources
can be evaluated in this manner.
One of the most important tasks is to match the
fugitive emission source to the sampling methods and control
methods most adaptable to that source. Fugitive sources
most amenable to measurement by the quasi-stack method are
readily controlled by use of a permanent hood and duct.
537
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Those sampled through roof monitors can best be controlled
by treatment of the individual in-plant sources which
produce the emission or, if necessary, the roof monitor
vent air itself. Those outdoor sources for which upwind-
downwind sampling techniques are applicable can be
controlled by such methods as enclosing individual sources
(e.g., transfer points) and ventilating through a control
system, placing operations creating fugitive emissions
in a building, improved maintenance, use of surface active
agents on exposed material piles, planting of vegetative
covering and paving and wetting of dusty plant roadways.
In addition, scheduling of operations to avoid fugitive
emissions could be considered as a method of administra-
tively controlling these emissions. An example would be
to avoid coal reclaiming on those days when wind direction
and speed and surface dryness would maximize fugitive
emissions and their impact on surrounding areas.
Table 13-7 is a matrix of the probable fugitive
emission sources, feasible sampling strategies and potential
control methods for a coal preparation plant. For overall
plant emissions, which will thereby establish its impact
on ambient air quality (stack and fugitive emissions), an
upwind-downwind sampling method is useful. It must be used
with tracers and modeling to serparate the coal dryer stack
emissions from the fugitive emissions. For individual
fugitive emission sources, quasi-stack or upwind-downwind
strategies are the most applicable. Although the upwind-
downwind strategy can be used for individual sources, some
tracer and modeling work must be done to separate individual
source contributions.
538
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Table 13-7
Fugitive Emissions from Coal Preparation Plants
Probable Source
Feasible Sampling
Strategies
Potential Control Methods
Coal Transport to Plant
and from Plant
Coal Storage Piles
Stacker-Reclaimer
Coal Conveyors
Crushing and screening
building
Waste Fines transfer
Waste storage
Cob Pile Fires
TOTAL PLANT
Upwind-Downwind
Upwind-Downwind
Quasi-stack or
Upwind-Downwind
Quasi-stack or
Upwind-Downwind
Roof monitor or
Quasi-stack
Quasi-stack
Upwind-Downwind
Upwind-Downwind
Upwind-Downwind
Cover railcars, trucks or conveyors
Use silos, wet pile, build wlndbreaker
Cover conveyor, hood reclaim wheel
Cover conveyors, hood transfer points
Enclose and treat building vents,
hood transfer points
Cover conveyors, hood transfer points
Use silos, wet pile, build windbreak,
use vegetation cover
Control dumping, dilute waste with
inert s
See individual sources
13.3.2.1 Exhaust hoods The use of exhaust hoods
over dust sources such as transfer points, screens and
crushers is the usual method of keeping the dust out of the
plant air and off the coal product. A minimum exhaust air
velocity of 300 feet per minute over the total opening is
usually effective in preventing the escape of all
objectionable dust. For best results, hoods must be very
carefully designed to utilize the direction of air currents
produced by the flow of coal and movements of machinery.
Since large air volumes are reflected in rather expensive
dust-collecting equipment, it is important to design hoods
having minimum opening and strong air motion close to the
dust source and yet with sufficient clearance for passage
of coal. It cannot be overemphasized that all hoods,
cover plates and air ducts must be arranged for quick and
convenient removal, for easy access to machinery and for
539
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cleaning purposes. In practice, many covers or enclosures
have been removed permanently to save the time required for
removing and replacing them. Air exhausted from hoods
seldom contains the coarser dust particles/ and the dust-
grain loading of this air is usually low. This often
permits the reuse of this dusty air for dedusting coal if
such is practiced.
The desirability of recirculating the dusty air is
apparent when one considers that the air quantities for
exhausting from hoods are considerable.
13.3.2.2 Ducts Air ducts are required for trans-
porting the dust-laden air from hoods or dedusters to the
dust-collecting apparatus. To prevent settlement of coal
dust an air velocity of 3000 feet per minute must be
maintained for all dust sections where settlement is likely
to occur, as in horizontal or slightly inclined sections
and turns.
Ducts must be designed to carry the maximum amount of
air that it is contemplated to use at a selected velocity
and pressure. A material increase or decrease in the air
velocity is sure to cause difficulties, either from dust
settling in the ducts or from insufficient fan and motor
capacity. In doubtful cases a duct larger than required
is preferable, as its area may be reduced by installing
baffles at suitable intervals from the top side of the
duct. Branches must enter the main duct at an angle of
about 30 degrees, but never exceed 45 degrees, preferably
near to the top and in the tapered section of the duct.
The inside of the duct must be smooth and free of
projections. Laps of joints should be in favor of the
air flow.
Bends and elbows are commonly designed with a radius
of not less than twice the diameter of the duct. Wear
540
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from abrasion is very severe on short radius'turns.
Airtight clean-out openings should be provided along the
bottom of the duct where dust might settle and always
where the dust changes directions or a branch enters.
Duct sections should be equipped with airtight joints
readily taken apart, either of the flange type with gaskets
or the removable band type. Ducts must be built of sheets
heavy enough to resist abrasion and also suction pressure
without pulsating. All dust-collecting equipment must be
strong enough and supported sufficiently to be safe if
accidentally filled with dust. Each dust installation has
its own particular problems that must be solved; vibration
from other units is one of them. In extreme cases it may
be necessary to use flexible connections between pipe
sections.
13.3.2.3 Mechanical Collection Equipment The types
of mechanical dust collection equipment may be broadly
grouped into six general classification types:
Gravity Settling Chambers—A gravity settling
chamber is, essentially, a relatively large
compartment into which a dust laden gas stream
enters to have its velocity greatly reduced so
that particles can settle out by the force of
gravity. This means of collection is effective
only for relatively coarse particles, since
the gravity settling rate of fine particles is
extremely low. For example, a coal dust particle
of 100 microns in diameter will settle at a rate
of about 70 feet per minute, a 10 micron particle
will settle at a rate of about one foot per
minute and a one micron particle will settle at
a rate of about 0.01 feet per minute.
Inertial Separators—An inertial separator
utilizes the difference in inertia between a gas
stream and the heavier suspended particles by
effecting a sudden change of direction of the gas
flow stream.
541
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Centrifugal Collectors—Centrifugal or cyclone
collectors employ centrifugal force to separate
the suspended particles from the gas stream. As
with the coal washing equipment of similar design,
the dust laden gas stream enters the cyclone
cylinder tangentially. The resulting centrifugal
force throws the dust particles to the wall of the
cylinder while the gas stream spirals upward to
an inner vortex and is discharged axially through
an outlet port. The dust particles fall downward
into the cone and are removed.
Wet Scrubbers—This term is applied to a wide
variety of equipment using various mechanisms to
bring about contact between dust particles and
water. The objective of wet scrubbers is to
cause the small dust particles to adhere to
larger droplets of water so that the effective
size of the dust particles is greatly increased,
enhancing their separation by mechanical means
such as impingement or inertial separation. To
increase the probability of contact between dust
particles and water in a scrubber, the water is
usually introduced in the form of a fine spray.
As they incoming gas stream and suspended
particles encounter the water droplets, the gas
flows around the droplets but the particles, due
to their greater inertia, tend to impinge on
the droplets.
Fabric Filters—In the fabric filter, the gas
stream with its suspended particles is passed
through a woven fabric at low velocity. The
fibers that comprise the fabric offer obstacles
to the flow and thus intercept the dust particles.
There are two primary types of bag filters, the
tube or bag type and the envelope type. In the
tube type, the individual filters are cylindrical
tubes, usually from five to 12 inches in diameter
and up to 30 feet in length. The individual
filters of the envelope type are cloth forms
stretched over a rectangular frame.
Electrostatic Precipitators—In the electrostatic
precipitator, the dust particles are electrically
charged by means of ionization of the carrier
gas and transported by the electric field to
collecting electrodes. The particles are then
neutralized on the collecting surfaces and removed
for disposal. The major components of an electro-.
542
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static precipitator are: a source of high voltage
current (up to 70,000 volts), an electrode system,
an enclosure to provide a precipitation zone and
a system for removing precipitated dust.
Each of these general categories have advantages or
disadvantages based upon their application to specific
problems. As indicated, the gravity settler is primarily
a large particle size collector. Because of its low
efficiency on fine dusts, the gravity settler is seldom
used for recovery of coal dust except where it can effec-
tively remove coarse, abrasive particles ahead of a more
efficient collector. Likewise, the inertial separator is
very inefficient for separation of small particles and
thus is of little value considering the present day
requirements for dust collection.
On the other hand, the cyclone collector is one of
the most widely used types of collectors in coal preparation
plants, even though the efficiency drops off rapidly at
about the 10 micron size levels. If the incoming gas flow
is increased in a given cyclone, the velocity of the
particles is also increased, thereby improving the separation
capability of the cyclone. However, increased velocity
also results in increased pressure differential and higher
power consumption. Concurrently, the separation force is
inversely proportional to the radius of the cyclone. Thus,
for any given cyclone velocity, a cyclone of smaller radius
\ .
will be more efficient at removing smaller particles than
will a cyclone with a larger radius. Therefore, to achieve
high efficiencies with cyclone collectors, a large number
of small radius cyclones in parallel may be employed
instead of a single large cyclone tube. It must be remem-
bered that within a cyclone, there is always considerable
turbulence because the outer vortex is moving downward,
while the inner vortex is moving upward. This turbulence
543
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causes some of the larger particles to be carried out with
the exhaust gas. There is, therefore, an overlapping in
the size distribution of materials caught and lost in
cyclones.
With wet scrubbers, which include spray chambers,
packed beds, wet cyclones, impingement scrubbers and
orifice or venturi scrubbers amongst their numbers,
practically any degree of efficiency can be attained, even
on sub-micron particles, if sufficient energy is expended
into the system. The necessary energy may be spent either
to create turbulence in the gas stream or to break up the
input water into a large number of small droplets and
propel them at a high velocity into the gas stream; or,
the energy may be expended as a combination of these methods
i
where energy from a motor is used to intimately mix the gas
stream and the water. In a spray chamber system, the gas
stream passes through a water spray that may be cocurrent,
countercurrent or normal to the gas flow with a minimal
energy expenditure; however, recovery efficiency for small
dust particles (those less than a few microns in size) is
also low. In a packed-bed scrubber, the gas stream flows
through a packing material usually concurrently to a stream
of water to achieve contact over a large surface area, but
requires more energy than a spray chamber. A packed scrubber
as depicted in Figure 13-28 can produce high mass and heat
transfer rates along with an ability to handle viscous
liquids and heavy slurries. A two stage scrubber operating
at a pressure drop of 8 to 10 inches of water gauge will
collect 98% of the particles greater than one micron.
In a wet cyclone, the action is similar to that in a
dry cyclone except that a stream of water is sprayed
radially across the gas stream. The fine dust is flushed
to the bottom of the vessel and discharged, and the clean
air is spun through a fixed entrainment separator and
544
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LIQUOR
D/STH/BUTCW
PACKINO
MATERIA
GAS
INLET
ENTRAPMENT
SEPARATOR
LIQUOR
INLET
RETAINING
GRID
STAGE!
SUPPORT
GRID
STAGE I
HUMIDIFICATION
SPRAYS
MAKE-UP
LIQUOR
LIQUOR
OUTLET
Figure 13-28
Surface Aera of Packed-Bed Scrubber
discharged to the atmosphere. In the impingement
collectors, the gas stream impinges upon a reservoir of
water and usually passes through the water to create a
turbulent layer of bubbles, gas and dust, which results in
a large contact area. A typical impingement scrubber
design is shown in Figure 13-29. The gases flow upward
through succeeding impingement plate stages and pass through
a separator stage where the gas velocity is accelerated,
casuing inertial separation of the retained water droplets.
This type of scrubber can remove 97% by weight of particles
above one micron in size with a gas velocity of 500 fpm at
an operating pressure drop of 2 to 3 inches of water
gauge per stage.
545
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CLEAN GAS
OUTLET
IMPINGEMENT
BAFFLE PLATE
STAGES
SPRAYS
DIRTY
INLET
ENTRAPMENT
SEPARATION
STAGE
SCRUBBING
WATER INLET
HUMIDIFICATION
WATER
DIRTY WATER
OUTLET
Figure 13-29
Typical Impingement Scrubber Design
In the so-called "high-energy wet scrubber", of which
the orifice and venturi scrubbers are the prime examples,
the gas stream passes at high velocity through a restricted
opening, at which point water is also introduced. At
the throat of the venturi, the gases, flowing at 12,000 to
18,000 fpm, produce a shearing force on the water stream
which casues the water to atomize into very fine droplets.
Impaction takes place between the dust entrained in the
gas stream and the liquid droplets. As the gas decelerates,
collision continues and agglomeration of the dust laden
water droplets takes place. A venturi-type scrubber
operating in a pressure drop range of 30 to 40 inches water
gauge is capable of an almost quantitative collection of
particles in the size range of 0.2 to 1.0 microns. As
546
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indicated, the general efficiency of wet collectors increases
as the pressure differential across the restriction
increases; however, a higher pressure differential also
means greater energy consumption. As with all wet scrubbers,
the resulting waste water slurry must be dewatered and the
water purified for reuse.
The fabric filter has its application where high
collection efficiency of extremely fine dust particles is
required and where gas temperatures and humidity are
moderate. Although bag houses operate at the highest
collection efficiency levels (99.9+ percent), they also
have serious limitations. For example, bag houses are
probably one of the most expensive solutions and they
usually require the most space for installation. On the
whole, however, bag houses generally require much less
energy to achieve their high-efficiency recovery and do not
have water requirements.
Electrostatic precipitators are excellent for specific
dust collection problems. The precipitators can collect
small particles down to less than one micron in size with
very low energy consumption and it can be built for high
difficulties encountered when using an electrostatic
separator in removing coal dust from air streams are due to
high humidity of the incoming gas and the possibility of
a spark discharge and the resultant explosion hazard.
13.3.3 Specific Applications to the Thermal Drying
Process
The most difficult air pollution problem associated
with the coal cleaning operation is the control of the ther-
mal dryers' emissions. The exhaust air with temperatures
up to 200° F. tnormally contains a great quantity of fine
particulates from the drying process and from the combustion
process and usually has a high moisture content. While a
547
-------
cloth collector would provide the desired cleaning
efficiency at a low pressure drop, the temperature and
moisture would present problems and make its reliability
extremely doubtful.
Years ago, thermal coal dryers, including our present
day fluid bed dryers, utilized only low pressure drop,
medium efficiency collectors. Exit concentrations were
in the range of 0.10 to 0.17 grains/dscf. With the recent
reductions in the allowable discharges from these dryers,
the coal operators have had to switch to a higher degree
of collection efficiency which cannot be met by the low
pressure drop, medium efficiency scrubbers. As a direct
result, the high pressure drop scrubber has emerged as the
only practical method to provide the required clean air.
As shown in Figure 13-30, the initial control device
for thermal dryers is a dry centrifugal collector which
retains up to 95% of the entrained fines and returns them
to the coal product. All secondary emissions control
systems are venturi type wet collectors. The venturi
collector can be fabricated in a number of shapes and
designs with great flexibility of operating pressure drop
and efficiency. This equipment normally requires 6 to 8
gallons of water/1000 cfm and allows recirculation of slurry
water up to 5% solids. The resulting water-dust slurry
is easily fed to the clarifier thickener for recovery.
13.4 NOISE POLLUTION CONTROL
The primary noise-producing mechanisms in coal
cleaning plant equipment are impacts, mechanical vibrations
and aerodynamic and hydrodynamic sources. Of these sources,
impacts are the most prevalent and include impacts of coal
and refuse against steel or vice versa. Mechanical
vibrations that are not the results of impacts occur due
548
-------
Un
i>
c
J.J.DAVIS
ASSOCIATES
Venturi Scrubber
Shown as Part of a
Complete Coal Dryer
Figure 13-30
DCN
-------
to vibrating feeders and screens or unbalanced rotating
equipment. Hydrodynamic or aerodynamic sources occur, in .
pumps/ compressors and values and consist of fluid pulsa-
tions or oscillators.
Two considerations are of importance in relation to
the noise produced by coal cleaning plants:
hearing damage to personnel employed in such
plants and
annoyance to people in communities near such
plants.
The maximum permissible noise exposure of plant personnel
is delineated by the Federal Coal Mine Health and Safety
Act of 1969, where it states that the standards of noise
prescribed under the Walsh-Healy Act shall be applicable
to each coal mine.
The occupational noise exposure portion of the Walsh-
Healy Act delineates the following:
Protection against the effects of noise exposure
shall be provided when the sound levels,
measured on the A scale of a standard sound level
meter at slow response, exceed the permissible
exposure shown in Table 13-8.
Table 13-8
Permissible Noise Exposures Prescribed by
the Walsh-Healy Act
Duration
(hours per day)
Permissible Sound
Level (dBA, slow
response)
8
90.
8
92
4
95
3
97
2
100
l»i
102
1
105
h
110
\ or
less
115
For impulsive or impact noise, the maximum
permissible sound pressure level corresponds
to a measured instantaneous peak value of 140 dB.
550
-------
When employees are subject to sound levels
exceeding these shown in Table 13-8, feasible
administrative or engineering controls shall be
utilized. If such controls fail to reduce the
sound levels to the values listed in the table
(or to lower values) personnel protective
equipment shall be provided and used to reduce
sound levels to the requirements of the table.
If the noise is unsteady and involves maxima that
occur at intervals of one second or less, the
noise is to be considered as steady.
In all cases where the sound levels exceed the
values specified by the Act, a continuing,
effective hearing conservation program must be
admini strered .
The noise dosage a worker recieves is determined by
the ratio of the length of time the worker spends in a
particular noise environment divided by the noise exposure
in that particular environment. If the worker is exposed
to several different sound levels, his total dosage would
be the sum of each of the individual dosages. The
equation for determining the dosage is :
D -
Tl T2 T3 Tn
where C is the actual duration of exposure at a given steady
state noise level and T is the noise exposure limit for
the level present during the time C. According to MESA (the
Mine Enforcement and Safety Administration) regulations, the
total dosage should not exceed unity (one) for any worker
for a full day of work. Figure 13-31 is a graph of time and
noise exposure expressed in hours per day to which a worker
can be exposed to each (A) weighted sound level.
Most existing statutes governing industrial community
noise prescribe maximum permissible A-weighted levels of
50 dB(a) for nighttime (10 p.m. to 7 a.m.) and 55 to 65
dB(a) for daytime, as measured at the boundaries of surroun-
551
-------
.Jl
6
c
4
3
z
>1
(fl
5 -•
in -!
a -i
0 -i
. 4
_]
.1
. 1
U..,—
t
I
- .,_
9
-v
0
1 '
—
\
\
\
!=r
i
--
\
\
— i
s
\
10
4
\
•— -
K>
DA
\
h —
-V
— s
i
\
'X
1
—
-..-
V
s
s
0
—
—
s
s
H
—
—
—
— i
—
Figure 13-31
Maximum Daily Noise Exposure Permitted by MESA
ding residential areas. These values assume that the
noise level fluctuates little with time; more stringent
restrictions may apply for fluctuating noise levels. Since
the noises emanating from coal cleaning plants tend to
be essentially non-fluctuating, one may take 50 dB(a) for
nighttime and 60 dB(a) for daytime operations—as measured
at the community boundary nearest the plant—to be
reasonable criteria.
Noise is defined simply as an unwanted audible sound.
An audible sound is a disturbance or vibration of air
sensed by people or wildlife. Anything that causes air
to vibrate or anything that sets something else in motion
which in turn causes air to vibrate may be considered a
noise source.
552
-------
Sound typically propagates from a source to a receiver,
i.e, to a person or item of equipment whose noise exposure
is of concern, via diverse paths. These paths may be very
complicated, involving not only reflections but also
conversions between vibrations of air and vibrations of
structural components. For example, a noise source in an
enclosure causes the enclosed air to vibrate, the air
vibrations set the enclosure walls into motion, which in
turn produces vibrations of the air outside the enclosure.
Virtually every noise problem may be approached
conceptually in terms of three basic elements:
sources,
paths and
receivers.
Noise control then, in essence, involves reduction of
noise generation by the significant sources, reduction of
the propagation of noise from the sources to the receivers
along defined paths and/or rendering the receivers more
tolerant to the noise. For example, rubber liners may be
used to reduce noise-producing impacts of coal on steel
chutes (reduction of noise generation at the source);
enclosures may be constructed around noisy machinery
(obstructing the noise propagation path); or the amount of
time a worker can spend in a noisy location may be limited
(making the worker more tolerant of a higher noise level
without suffering hearing damage).
13.4.1 Reduction of Preparation Plant Noise
The majority of preparation plant functions are con-
trolled from a central operator's position, with the
operator at some distance from the equipment itself. Few
items of equipment require by their nature immediate
553
-------
physical contact between a worker and the equipment or the
coal being processed. Therefore, noise control enclosures
would not directly impede the coal cleaning process.
However, it is mandatory that preparation plant personnel
see the flow of coal through chutes and screens and across
table decks, thereby complicating the design of close-
fitting enclosures and limiting their utility. In
addition, the maintenance activities of a preparation
plant frequently includes cutting and welding of worn or
damaged parts. Therefore, noise reduction treatment
applied to any surfaces subject to repair by these means
must not impede torch-cutting either by being unsafe or
by being prohibitively expensive to replace. Also, during
routine maintenance of the plant equipment, it is often
times necessary to move large items of equipment. This
means that any noise control enclosure or partitions must
have large doors, be accessible from overhead or be
completely removable. The primary safety concern in any
coal cleaning plant is dust buildup and the resultant fire
and explosion hazard. Thus, fibrous acoustical materials
which tend to retain dust cannot be used without expensive
treatment. Additionally, all noise reducing installations
must be designed for easy cleaning by water hosing.
An effective noise control program must first attack
the noisiest sources. However, only those sources that
contribute to worker exposure are important from the
standpoint of industrial health. For this reason, the
importance of quieting a noise source depends both upon
the noise level and the proximity of the workers.
Table 12-7 presented a rank ordering of machinery,
taking into account noise levels and the proximity of the
workers under normal operating conditions. Although several
sources offer conflicting ranking priorities, it is generally
554
-------
concluded that the most severe hearing damage-risk problem
is associated with the car shakeout operations. The second
most significant problem is associated with vacuum filter
blowers and vacuum filter pumps. The third most significant
noise control problem and the one contributing most to the
structural vibration is associated with the vibrating
screens used in abundance throughout the plant.
The following item by item discussion deals with
specific available noise treatments applicable to various
items of preparation plant machinery and are paraphrased
from Coal Cleaning Plant Noise and Its Control prepared
by E. E. Ungar, et al of Bolt Beranek and Newman, Inc. in
1974 for the U. S. Bureau of Mines.
Car Shakeouts—The pounding of the shakeout
mechanism against the railcar side cannot be
reduced without reducing its efficiency for
unloading the car. Padding of the contacting
surfaces or clamping the shaker to the car sides
would reduce the noise, but also the efficiency
of the unloading operation. The only practical
means for dealing with the noise of shakeouts
consists of providing an enclosure for the
shakeout operator and his helper. The enclosure
must provide at least 40 dB(a) of noise reduction.
Its walls and ceilings need to be built of
massive panels, its door should be self-closing
with airtight rubber seals and its window must
be double-glazed.
Vacuum Blowers and Pumps—The in-plant noise
associated with the vacuum blowers and pumps
comes primarily from the air inlets and discharges.
The noise is typically dominant, pure-tone
(single-frequency) components at frequencies
that correspond to the rotor lobe or fan blade
passage rates and harmonies of those. Noise
control can best be accomplished by means of
mufflers or ducts affixed to the ports. Where
the predominant noise is a single tone at a
fixed frequency, mufflers tuned to this frequency
are quite useful. If the dominant noise consists
of a multitude of pure tones and/or broadband
noise, then a muffler consisting of a long,
555
-------
labyrinthe, acoustically lined duct is required
for muffling purposes.
Screens—The simplest add-on method for reducing
the noise generated by screens consists of
building an enclosure around the screen. Noise
reductions of 10 to 15 dB(a) may be realized
with enclosures that also cover the driving
mechanism. Few such installations are antici-
pated due to projected problems related to screen
maintenance, screen observation difficulties or
enclosure life and safety problems.
Replacement of the steel decks with rubber-coated
or other resilient duct material would reduce
the severity of impacts and the associated noise.
Reductions on the order of 5 to 10 dB(a) may be
expected for the impact-related component of
screen noise, but the total noise reduction would
be only between 2 and 8 dB(a). The performance
and economic advantages and problems of rubber
coated and similar decking are not clear.
Although the initial cost is about three times
_of iL°Jiy_ei^ki°nal decks, the estimated life
^ the "coated screen""deck's"' Tsf'pro jTect'ed" t6"T5e~
between three and five times that of conventional
steel decks.
Reduction of impact severity and the associated
noise may be obtained also by reducing the stroke
and speed of the shaking mechanism. However, the
screens process flow capabilities will be
greatly diminished, making this approach
unacceptable.
Reduction of the noise contributed by the eccentric
weight driving mechanism may be achieved by use
of gearing manufactured to closer tolerances and
tighter bearings. Additionally, covering the
mechanism with a closely fitting enclosure that
is acoustically lined and vibration-isolated
from the case would offer noise reduction
potential up to 10 dB(a); however, the associated
cooling and maintenance problems are not known.
Where the noise is caused by a chattering of the
screen supporting springs against the mounting
pads or screen frame, insertion of a resilient
pad between the spring end and the associated
chattering point may produce a 5 dB(a) reduction.
556
-------
Alternatively, replacement of the springs with
air bags at a considerable expense would yield a
15 dB(a) reduction.
Hoppers/ Bins and Chutes—Impact noise reductions
of about 5 dB(a) can be achieved by lining the
hoppers, bins and chutes with rubber or similar
covering although the availability, wear,
repairability and costs are not known. A widely
employed useful approach consists of placing
welded ledges or similar obstructions to the
material flow on the walls so that a protective
layer of material remains in place to absorb
the impact.
Air Valves and Air Blasts—Water valves are not
a significant noise source. However, air valves
and blasts have significant noise levels. Air
valves like those on Baum jigs tend to be
extremely noisy due to the explosive and hissing
noise associated with the venting process. The
noise control methods for these air valves is
the same as that for vacuum pumps and tends to be
expensive.
The air blasts that are used to aid material
flow in chutes and hoppers generate loud hissing
noises due to the high air exit velocity and the
impingement of the air stream on solid surfaces.
A velocity reduction of 20% should result in
little loss of material moving but may reduce
the noise level by several dB(a).
13.4.2 Control of Plant Noise Intrusion into Nearby
Communities
As in most noise problems, the generally most effective
means for control consist of reducing the noise at its
source. The coal preparation plant noise that reaches
nearby communities typically is due primarily to only a
few items of machinery or equipment that are (a) much
noisier than others, (b) located outside the plant
buildings or near openings (doors or windows) in such
buildings, and/or (c) located near the observation
position. In most practical situations, the offending item(s)
557
-------
can be picked out simply by listening to the noise and by
knowing the operating cycles and closed-in noise character-
istics of the likely problem items.
Once the prime contributors to the observed noise have
been identified, they may be quieted by the various
applicable techniques that have been described in the
previous section.
For items located inside plant buildings near
openings, significant noise reduction can often be obtained
by closing these openings. Where total closure is not
feasible, i.e., because of ventilation or continuous
accessibility requirements, operators may alternatively
provide these openings with mufflers or barriers. Mufflers
would in essence appear like tunnels or ducts extending
from doors or windows, with acoustical lining on their
insides. These tunnels and ducts should be curved or
bent to eliminate all "line-of-sight" communication
between the inside of the building and the outside, and
they should be several times as long as their greatest
cross-sectional dimension.
Barriers consisting of walls or panels placed outside
of the doors and windows should also be placed so as to
eliminate the possibility of line-of-sight contact between
the inside and the outside. These barriers should not be
flat and parallel to the building wall; they will work
better if they are curved or accordion pleated. They do
need to be covered with acoustically absorptive material
on the side nearest the noise source, and they generally
need to be considerably larger than the openings they
protect.
Building walls that are of relatively lightweight
sheet metal and/or plastic present little obstruction to
558
-------
noise. Since most of the noise goes through the walls,
closing off of openings in such walls has no appreciable
effect on the noise reaching nearby communities. In such
cases, the needs to consider quieting of all of the noisy
equipment in the plant and/or improving the plant walls by
adding secondary, preferably heavy, walls outside the ones
that are already there may have to be considered.
Where possible community reaction to noise is a problem,
operators obviously should not reduce the in-plant noise
produced by valves, and by air intakes and exhausts by
ducting these to the exterior of the plant. If such ducting
already exists and if the noise emanating from it may
bother the community, mufflers should be added at the ends
of these ducts.
Walls or earth berms constitute useful means for
protecting communities from plant noise provided, however,
that these are close enough to the noise source and large
enough so that the shortest sound path around these
barriers is longer by a considerable percentage than the
most direct sound path in absence of the barrier. Thus,
impractically large barriers are required to have a
significant effect on communities located at considerable
distance from the plant.
Weather, notably wind, temperature gradients and
humidity also affect the long-range propagation of sound.
Particular combinations of conditions enhance this propa-
gation, others impede it. The operator may always expect
occasions where sound refracted by the atmosphere greatly
reduces the effectiveness of a given barrier installation.
559
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REFERENCES AND/OR ADDITIONAL READING
Akers, David J., Jr.; & Moss, Edward A.; "Dewatering of Mine Drainage
Sludge — Phase II", Office of Research and Monitoring, EPA
R2-73-169, February 1973
Altmare, Philip M., "The Application of the Tall Stack and Meteor-
ology in Air Quality Control of SO ", Coal Utilization Symposium —
Focus on SO Emission Control, Louisville, Kentucky, October, 1974
AMAX Henderson, "An Experiment in Ecology", Editorial Alert - 1974,
Mountain Empire Publishing Company
American Public Health Association, American Water Works Association &
Water Pollution Control Federation, "Standard Methods for the
Examination of Water and Wastewater" (13th Ed.), APHA, Washington,
D.C., 1971
American Society for Testing Materials, "Standard Methods for (1)
Collection of a Gross Sample of Coal, (2) Preparing Coal Samples
for Analysis", Part 19
Anderson, J.C., "Coal Waste Disposal to Eliminate Tailings Ponds",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Atwood, Genevieve, "The Technical and Economic Feasibility of
Underground Disposal Systems", Coal and Environmental Technical
Conference, October 1974
Atwood, Genevieve, "The Technical and Economic Feasibility of
Underground Disposal Systems", First Symposium on Mine and Prepa-
ration Plant Refuse Disposal, Louisville, Kentucky, October 1974
Balzer, J.L.; Urouch, D.B.; Poyser, R.W.; Sowards, W., "A Venture
Into Reclamation", American Mining Congress Convention, October 1974
Barnes, H.L. & Romberger, S.B., "Chemical Aspects of Acid Mine Drain-
age", Western Research Application Center, University of Southern
California, #CA-67
Battelle-Columbus, "SO Control: Low-Sulfur Coal Still the Best Way",
Power Engineering, November 1973
Bechtel, Inc., "Coal Slurry Pipeline—An Environmental Answer", San
Francisco, California
Benza, Stephen T. & Lyon, Anne E., "The Use of Lime, Limestone and
Other Carbonate Material in the New Coal Era", NCA/BCR Coal
Conference and Expo II, October 1975
560
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Bisselle, C.A.; Haus, S.A.; Lubore, S.H.; School, M.M.; S Wilcox, S.L.,
"Strategic Environmental Assessment System: Initial Analysis of
Environmental Residuals", The Mitre Corporation, February 1973
Bituminous Coal Research, Inc., "Glossary - Surface Mining &
Reclamation Technology", October 1974
Black Sivalls & Bryson, Inc.-, "Study of Sulfur Recovery from Coal
Refuse", U.S. Government Printing Office, September 1971
Bluck, W.V. & Norton, G., "High Intensity Fine Coal Flotation",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Bioko, V.A. Parinskiy, O.P., "Equipment for Dewatering of Coal",
Chapter 5 of "Hydraulic Capability for Underground Mining of Coal",
Katalog-Spravochnik, Moscow, 1965 (Translated by Terraspace)
Bowen, James B. & Guiliani, R.L., "The Integrated Occupational Health
Program of the Erie Mining Company", American Mining Congress
Convention, Las Vegas, Nevada, October 1974
Brawner, C.O.; Pentz, D.L.; Campbell, D.B., "Ground Stability in
Surface Coal Mines", American Mining Congress Coal Convention,
Pittsburgh, Pennsylvania, May 1975
Brundage, R. Scott, "Depth of Soil Covering Refuse (GOB) vs Quality
of Vegetation", Coal and the Environment Technical Conference,
October 1974
Bureau of Water Quality Management, "Air and Water Quality Regulations"
Busch, Richard A.; Backer, Ronald R.; Atkins, Lynn A., "Physical
Property Data on Coal Waste Embankment Materials", U.S. Bureau of
Mines RI 7964, 1974
Capp, John P.; Gillraore, D.W.; Simpson, David G., "Coal Waste Stabili-
zation by Enhanced Water", American Mining Congress Coal Convention,
Pittsburgh, Pennsylvania, May 1975
Cassady, Jon M., "Obstacle Course for Permits and Approval", American
Mining Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Chedgy, David G., "Reduction of Environmental Noise Levels at the
Meadow River No. 1 Preparation Plant", American Mining Congress Coal
Show, Detroit, Michigan, May 1976
561
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Chemical Construction Corporation, "The High Sulfur Combustor - A Study
of Systems for Coal Refuse Processing", New York, New York,
February 1971
Chironis, Nicholas P., "Results of a Noise Control Program at a New
Coal Preparation Plant", Coal Age, January 1976
Coal Research Bureau, "Underground Coal Mining Methods to Abate
Water Pollution", West Virginia University, 1970
Consolidation Coal Company, "Conveying a Slurry Through a Pipeline",
British Patent #861-537, February 1961
Cooper, Donal K., "Choosing Closed Circuits for Coal Preparation
Plants", American Mining Congress Coal Show, Detroit, Michigan,
May 1976
Corp, Ernest L.; Schuster, Robert L.; McDonald, Michael W., "Elastic-
Plastic Stability Analysis of Mine-Waste Embankments", U.S. Bureau
of Mines RI 8069
Gulp-Gulp, "Advanced Waste Water Treatment", Van Norsten, 1971
Cutler, Stanley, "Emissions from Coal-Fired Power Plants", U.S.
Department of Health, Education and Welfare, 1976
Dahlstron, D.A.; Silverblatt, C.E., "Dewatering of Pipeline Coal",
U.S.A., Australian Coal Conference
Danielson, John A. (Editor), "Air Pollution Engineering Manual (2d Ed.)",
U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina, 1973
D'Appolonia, E., "Engineering Criteria for Coal Waste Disposal", Mining
Congress Journal, October 1973
Day, James M., "Current Status of Proposed Federal Waste Disposal Rules",
Mining Congress Journal, June 1974
Dean, K.C.; Havens, Richard; Blantz, M.W., "Methods and Costs for
Stabilizing Fine-Sized Mineral Wastes", ULSL Bureau of Mines RI 7896
1974
Dean, Karl, C.; Havens, Richard, "Methods and Costs for Stabilizing
Tailings Ponds", Mining Congress Journal, December 1973
562
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Decker, Howard; Hoffman, J., "Coal Preparation, Volume I & II",
Pennsylvania State University, 1963
Decker, Howard W., Jr.; Hoffman, John N., "Dedusting, Dust Collection
and Coal Surface Treatment (Chapter E}", Coal Preparation, Volume II,
Pennsylvania State University, 1963
Department of Environmental Resources, "Solid Waste Management", State
of Pennsylvania
Department of Environmental Resources, "Waste Water Treatment Require-
ments"; "Industrial Wastes"; "Special Water Pollution Regulations";
"Erosion Control", State of Pennsylvania
Department of Environmental Resources, "Water Quality Criteria",
State of Pennsylvania
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Division of American Society Civil Engineering, "Journal of Sanitary
Engineering"
Dokunin, A.V.; Onika, D.G., "Hydraulic Underground Mining", Translated
for Branch of Bituminous Coal Research, Division of Bituminous Coal,
U.S. Bureau of Mines
Doyle, Frank J.; Bhatt, H.G.; Rapp, J.R., "Analysis of Pollution
Control Costs", Report prepared for Appalachian Regional Commission
and Office of Research and Development of the EPA, EPA 670/2-74-009
February 1974
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Analysis of Pollution Control
Costs", EPA 670/2-74-009
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Chemistry & Classification of
Mine Drainage", EPA 670/2-74-009
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "National Ambient Air Quality
Standards", EPA 670/2-74-009, February 1974
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Other Mine Drainage Abatement
Procedures", EPA 670/2-74-009, February 1974
563
-------
REFERENCES AND/OR ADDITONAL READING
(Continued)
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Refuse Bank & Mine Fires",
EPA 670/2-74-009, February 1974
Dunnigan, A.R.; Dennis, R.A., "Control System for a Very Wide Range
pH Effluent Stream"
Durard, John, "Permissible Noise Exposure—Walhealey Tables"
Ellison, Ricahrd D.; Almes, Richard G., "Synopsis of Engineering and
Design Manual for Coal Refuse Embankments ", Coal and the Environment
Technical Conference, October 1974
Ellison, William; Heden, Stanley D.; Kominek, Edward G., "System
Reliability and Environmental Impact of SO Processes", Coal Utili-
zation Symposium-Focus on SO Emission Control, Louisville, Kentucky,
October 1974
Enviro-Clear Co., Inc., "Coal Preparation Plant Clarifier-Thickener",
Bulletin C/ll/74, New York City
Environmental Analysis, Inc., "Air Quality in Nassau-Suffolk County,
N.Y.", 1972
Environmental Protection Agency, "Air Pollution Emission Factors",
EPA Publication AP-72, April 1973
Environmental Protection Agency, "Air Pollution Technical Publications
of the Environmental Protection Agency, Research Triangle Park, North
Carolina, July 1974
Environmental Protection Agency, "Background Information for Standards
of Performance: Coal Preparation Plants (Volume I: Proposed
Standards)", Emission Standards & Engineering Division, EPA, Research,
Triangle Park, North Carolina, October 1974
Environmental Protection Agency, "Background Information for Standards
of Performance: Coal Preparation Plants (Volume II: Test Data
Summary)", EPA, Research Triangle Park, North Carolina, October 1974
Environmental Protection Agency, "Environmental Impact Assessment
Guidelines for Selected New Source Industries"
Environmental Protection Agency, "Municipal Sewage Treatment Standards
Fair, Geyer, and Okun, "Water and Waste Water Engineering", Vol. 2,
Wiley and Sons, 1968
564
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Fairhurst, Charles, "European Practice in Underground Stowing of Waste
from Active Coal Mines", First Symposium on Mine and Preparation
Plant Refuse Disposal, Louisville, Kentucky, October 1974
Falkie, Thomas W., "Overview of Underground Refuse Disposal", First
Symposium on Mine and Preparation Plant Refuse Disposal, Louisville,
Kentucky, October 1974
Falkie, Thomas W., "Overview of Underground Refuse Disposal", Coal
and the Environment Technical Conference, October 1975
Federal Register, "Mineral Resources - Rules and Regulations", Title
30, Chapter 1, Part 77
Federal Register, "Standards of Performance for New Stationary
Sources (Coal Preparation Plants)", Volume 39, #207, Part II,
EPA, October 24, 1974
Fletcher, J.R.; Schurtz, G.D., "Sulfuric Acid as a Soil Amendment to
Enhance Plant Growth", American Mining Congress Convention,
October 1974
Fomenko, T.G.; Kondratenko, A.F.; Perlifonov, A.G., "Thickening of
Flotation Tailings in a Thickener with a Sludge Packer", UGOL #1,
1973
Foreman, William E.; Lucas, J. Richard, "Current Status of Hydro-
cyclone Technology", Mining Congress Journal, December 1972
Foreman, William E., "Impact of Higher Ecological Costs and Benefits
on Surface Mining", American Mining Congress Coal Show, Detroit,
Michigan, May 1976
Goodridge, Edward R., "Duquesne Light Maximizes Coal Recovery at its
Warwick Plant", Coal Age, November 1974
Gospodarka, Gornictwa, "Possibilities of Mechanical Preparation Under-
ground", 1956 No. 4
Gregory, M.J., "Problems Associated with Closing Plant Water Circuits",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
Greenwald, Edward H., Jr., "A Landscape Architect Looks at Site
Planning and Surface Development of Coal Mining", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
565
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Grim, E.G.; Hill, R.D., "Environmental Protection in Surface Mining
of Coal", NERC, Cincinnati, Ohio, October 1974, EPA 670/2-74-093
Grimm, Bobby M., "Preparation Plant Corrosion Cost", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
Gvozdek, G.; Macura, L., "Hydraulic Mining in Some Deep Pits in
Czechoslovakia", Translated by National Coal Board (A 1683), Uhli
#12, December 1958
Hill, Ronald D., "Water Pollution From Coal Mines", Water Pollution
Control Association of Pennsylvania, 45th Annual Conference, 1973
Hoffman, L.; Truett, J.B.; Aresco, S.J., "An Interpretative Compilation
of EPA Studies Related to Coal Quality & Cleanability", Mitre
Corporation, May 1974, EPA 650/2-74-030
Hoyle, D.L., "The Effect of Process Design on pH & Pion Control",
Eighteenth ISA-AID Symposium, May 3, 1972
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Province Coalfield", France, Australian Coal Conference
Ivanov, P.N.; Kotkin, A.M., "The Main Trends in Development of
Beneficiation of Coal and Anthracite in the Ukraine", Ugol Ukrainy
#2, February 1975 (Translated by Terraspace)
Journal of American Water Works Association
Joy Manufacturing Company, "Basic Handbook of Air Pollution Control
Equipment", Western Participation Division, 1975
Kalb, G. William, "The Attainment of Particulate Emission Standards
at Fluidized-Bed Thermal Coal Dryers", American Mining Congress
Coal Show, Detroit, Michigan, May 1976
Kalika, Peter W.; Bartlett, Paul T.; Kenson, Robert E.; Yocum, John E.,
"Measurement of Fugitive Emissions", 68th Annual APCA Meeting,
Boston, Massachusetts, June 1975
Kenson, R.E.; Kalika, P. W.; Yocom, J.E., "Fugitive Emissions from
Coal", NCA/BCR Coal Convention and Expo II, October 1975
Kent, James A. (Editor), "Riegel's Handbook of Industrial Chemistry
(7th Ed.)", Van Nostrand Reinhild Publishing Company, New York, 1974
566
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Keystone, "Coal Preparation Methods in Use at Mines", pp. 230-240
Kilgore, James D., "Physical and Chemical Coal Cleaning for Pollution
Control", Industrial Environmental Research Laboratory, Environmental
Protection Agency, Research Triangle Park, North Carolina
Knuth, William M., Jr.; Charbury, H. Beecher, "Remote Sensing Techniques
for Analysis of Burning in Coal Refuse Banks", Coal and the Environ-
ment Technical Conference, October 1974
Koch Engineering Company, "Engineering Manual, Wet Scrubbing Systems
for Air Pollution Control", Bulletin KPC2
Kodentsov, A.A.; Kurkin, V.F.; Krasnoyarskiy, L.S.; Papkov, M.N.,
"Dewatering of Coal and Rock, Clarification of Waste Water During
Driving by Hydromechanization", Ugol Ukrainy #11 (Translated by
Terraspace)
Kollodiy, K.K.; Borodulin, V.A.; Nazarov, P.G., "Processing of Coal
Mined by the Hydraulic Method", Ugol #9, 1974 (Translated by
Terraspace)
Korol, Dionizy, "Influence of Hydraulic Getting on Mechanical Coal
Preparation", Przeglad Gorniczy, Year 12 #12, December 1956
(National Coal Board Translation Section)
Kosowski, Z.V., "Control of Mine Drainage from Coal Mine Mineral
Wastes, Phase II - Pollution Abatement & Monitoring", EPA R2-73-230,
May 1973
Krebs Engineers, "Brochure and Letter - June 1975"
Lamonica, J.A., "Noise Levels in Cleaning Plants", Mining Congress
Journal, July 1972
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Leven, P., "Pumping: A Good Way to Dispose of Coal Plant Refuse",
Coal Mining and Processing, June 1966
Lombardo, J.L., "State-of-the-Art—Acid Mine Drainage Control",
American Mining Congress Mining Convention/Environmental Show,
Denver, Colorado, September 1973
567
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Lotz, Charles, W., "Notes on the Cleaning of Bituminous Coal", School
of Mines, West Virginia University, 1960
Lownie, H.W. et al., "A Systems Analysis Study of the Integrated Iron
and Steel Industry", EPA Project PH-22-68-65 Report
Lowry, H.H. (Editor), "Chemistry of Coal Utilization", John Wiley &
Sons, Inc., New York, New York, 1963
Luckie, Peter T.; Draeger, Ernie A., "The Very Special Considerations
Involved in Thermal Drying of Western Region Coals", Coal Age,
January 1976
Lusk, Ben E.; Piper, William L. (W. Va. Surface Mining and Reclamation
Association), "Progress Report—Longwall Stripping", American Mining
Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Magnuson, Malcolm 0., Baker, Eugene C., "State-of-the-Art in
Extinguishing Refuse Pile Fires", Coal and the Environment Technical
Conference, October 1974
Maneval, David R., "Assessment of Latest Technology in Coal Refuse
Pile Fire Extinguishment", American Mining Congress Coal Show,
Detroit, Michigan, May 1976
Manwaring, L.G., "Coarse Coal Cleaning at Monterey No. 1 Preparation
Plant", Mining Congress Journal, March 1972
Manzual, David R.; Lemezis, Sylvester, "Multistage Flash Evaporation
Systems for the Purification of Acid Mine Drainage", SME/AIME
Translations, Vol. 252
Margolf, Charles W., "Public Information—Industrial Involvement"
American Mining Congress Coal Show, Detroit, Michigan, May 1976
Martin, John F., "Quality of Effluents from Coal Refuse Piles", Coal
and the Environment Technical Conference, October 1974
Mathur, S.P., "Hydraulic Mining of Coal", Journal of Mines, Metals and
Fuels, May 1972
McCormack, Donald E., "Soil Reconstruction: Selecting Materials for
Surface Placement in Surface-Mine Reclamation", American Mining
Congress Coal Show, Detroit, Michigan, May 1976
McGauey, "Engineering Management of Water Quality", McGraw-Hill, 1968
568
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Metcalf & Eddy Incu, "Waste Water Engineering, Collection-Tr<->atment-
Disposal", McGraw-Hill
Meyers, Sheldon, "The Development of Coal Resources and the Environ-
mental Impact Statement", Coal Utilization Symposium-Focus on SO
Emission Control, Louisville, Kentucky, October 1974
Mill, Ronald, "Control & Prevention of Mine Drainage", Battelle
Conference 72, November 1972
Miller, F.; Wilson, E.B., "Coal Dewatering - Some Technical and
Economic Considerations", American Mining Congress Coal Convention,
May 5-8, 1974
Mitchell, Donald W.; Murphy, Edwin M., "Case Study of Mine Sealants",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1976
Mooman, H.F.; Zachar, F.R.; Leonard, Joseph W., "Feasibility Study
of a New Surface Mining Method, 'Longwall Stripping1", EPA 670/2-
74-002, February 1974
Moss, E.A.; Akens, D.J., Jr., "Dewatering of Mine Drainage Sludge",
EPA R2-73-169, February 1973
Moulton, Lyle K.; Anderson, David A.; Hussain, S.M.; Seals, Roger K.,
"Coal Mine Refuse: An Engineering Manual", Coal and the Environment
Technical Conference, October 1974
Nalapko, I.A.; Shevchenko, I.A.; Manza, P.I., "Industrial Tests of a
Plant Unit for the Extinction and Transportation of Slag and Ash"
Nalco Chemical Company, "Brochure and Letter - 1975"
Nalco Chemical Company, "Removal of Particulates from Gaseous Emissions",
Oak Brook, Illinois, July 1974
National Coal Association, "National Ambient Air Quality Standards—
Environmental Protection Agency"
National Coal Association, "First Symposium on Mine & Preparation Plant
Refuse Disposal", Coal and the Environment Technical Conference,
October 1974
National Coal Association, "Research and Applied Technology Symposium
Mined-Land Reclamation", National Coal Association Convention,
Pittsburgh, Pennsylvania, March 1973
569
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
National Coal Association, "Third Symposium on Surface Mining and
Reclamation, Volume I", NCA/BCR Coal Conference and Expo II,
October 1975
National Coal Association, "Third Symposium on Surface Mining and
Reclamation, Volume II', NCA/BCR Coal Conference and Expo II,
October 1975
National Coal Board, "Exploratory Trails in Hydraulic Mining at
Trelewis Drift Mine", September 1961
National Coal Board, "Hydraulic Transport of Coal at Woodend Colliery",
September 1961
Nirtsiyev, "Hydraulic Extraction of Coal in the Donetz Basin Izdatel
'Stvo "NEDRA", Moscow 1969 (Translated by Terraspace)
Nunenkamp, David C., "Survey of Coal Preparation Techniques for
Hydraulically Mined Coal", Published for Terraspace Inc., July 1976
O'Brien, Brice, "Environmental Protection", Mining Congress Journal,
February 1974
O'Brien, Ellis J.; Walker, Joseph L., "Environmental and Processing
Innovations—Bullitt Preparation Plant", American Mining Congress
Coal Convention, Pittsburgh, Pennsylvania, May 1973
O'Brien Ellis J.; Sharpeta, Kenneth J., "Water-Only Cyclones; Their
Functions and Performance", Coal Age, January 1976
Okhrimenko, V.A.; Kuprin, A.I.; Ishchuk, I.G., "Baring and Working
Hydromine Fields (Chapter 2}", "Automation of Hydraulic Extraction
(Chapter 11)", Moscow, 1974
Parkes, David M; Grimley, A.W.T., "Hydraulic Mining of Coal", American
Mining Congress Coal Convention, Pittsburgh, Pennsylvania, May 1975
Patterson, Richard M., "Closed System Hydraulic Backfilling of Under-
ground Voids", First Symposium on Mine and Preparation Plant Refuse
Disposal, Coal and the Environment Technical Conference, October 1974
Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
Desulfurization", Chicago, Illinois, October 1965
Peluso, Robert G., "A Federal View of the Coal Waste Disposal Problem",
Mining Congress Journal, January 1974
570
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Peterson, Gerald, "Noise Control in Coal Preparation Plants", Mining
Congress Journal, January 1974
Phelan, J.E., "Applications of Wet Scrubber Additives", EPA & APT
Symposium, San Diego, California, May 1974
Pollution Engineering Magazine, "Applying Air Pollution Control
Equipment", Environmental Handbook Series
Pollution Engineering Magazine, "Industrial Solid Waste Disposal",
Environmental Handbook Series
Poundstone,William, "Problems in Underground Disposal in Active Mines",
First Symposium on Mine and Preparation Plant Refuse. Disposal,
Coal and the Environment Technical Conference, Lousville, Kentucky,
October 1974
Powell, J.R.; Kopp, J.,- Reich, M.; Steinberg, M., "Photodeformation
Measurements of Refuse Pile Structure Movements", Coal and the
Environment Technical Conference, October 1974
Pritchard, David T., "Closed Circuit Preparation Plants and Silt Ponds",
Mining Congress Journal, November 1974
Protopapas, Panayotis, "A Report in Mineral Processing", Department of
Applied Earth Sciences, Stanford University, 1973
Protsenko, I.A., "The Technology of Beneficiation and Dewatering of
Coal Mined by the Hydraulic Method", Questions Regarding the Hydraulic
Production of Coal, Trudy VNIIGidrougol, Vol. XI, 1967 (Translated
by Terraspace)
Reiss, Irvin, "Surface Mining and Interim Land Use", American Mining
Congress Convention, October 1974
Richardson, James K., "Improving the Public Image of the Mining
Industry", American Mining Congress Convention, October 1974
Roberts & Schaefer Company, "Material Handling and Processing Facilities
for the Mining Industry", 1974
Roberts & Schaefer Company, "Research Program for the Prototype Coal
Cleaning Plant, January 1973
Rubin, E.S.; MacMichael, F.C., "Impact of Regulations on Coal Conversion
Plants", Environmental Science & Technology, 9, 112, 1975
571
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Sarkar, G.G.; Konar, B.B.; Sakha, S.; Sinha, A.K., "Demineralization
of Coal by Oil-Agglomeration", Part I: Studies on the Applicability
of the Oil-Agglomeration Technique to Various Coal Beneficiation
Problems, India, Australian Coal Conference
Scott, R.B.; Hill, R.D.; Wilmoth, R.C., "Cost of Reclamation & Mine
Drainage Abatement, Elkins Demonstration Project", Federal Water
Quality Administration Publication #14010
Scott, Robert B., "Sealing of Coal Refuse Piles", Program Element
1B2040, NERC-USEPA, Cincinnati, Ohio, July, 1973
Seibel, Richard J., "Dust Control at a Transfer Point Using Foam and
Water Sprays", U.S. Bureau of Mines Respirable Dust Program Technical
Progress Report, May 1976
Shields, Donald H., "Innovations in Tailings Disposal", Coal and the
Environment Technical Conference, October 1974
Sittig, Marshall, "Environmental Sources and Emissions Handbook",
Data Corporation, Park Ridge, New Jersey, 1975
Skinderowicz, F., "Typical Technical Solutions of a Loading Point
During Gravity Hydraulic Transportation of Coal", Wiadomosci
Gornicza, Vol. 10 #3, 1959
Sorrell, Shawn T., "Establishing Vegetation on Acidic Coal Refuse
Materials Without Use of a Topsoil Cover", Coal and the Environment
Technical Conference, October 1974
Stanin, S. Anthony, "Influence of Coal Waste Disposal Regulations",
American Mining Congress Coal Show, Detroit, Michigan, May 1976
Stefanko, Robert; Ramani, R.V.; Chopra, Ish Kumar, "The Influence of
Mining Techniques on Size Consist and Washability Characteristics
of Coal", National Technical Information Service, Springfield,
Virginia, August 1973
Terchick, A.A.; King, D.T.; Anderson, J.C., "Application and Utiliza-
tion of the Enviro-Clear Thickener in a U.S. Steel Coal Preparation
Plant", Transactions of the SME, Volume 258, June 1975
Tyree, P.O.; Anderson, M.M., "Pilot Studies in Wet Dust Control",
Mining Congress Journal, September 1973
Ungar, Fax, Patterson, Fox, "Coal Cleaning Plant Noise and Its
Control", Bolt, Beranek, & Newman, Inc., U.S. Bureau of Mines
Contract No. H0133027
572
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
U.S. Bureau of Mines, "Implications of the Water Pollution Control
Act of 1972 for the Mineral Resource Industry: A Survey", Inter-
disciplinary Research Task Force Committee, 1975
U.S.S.R., "Intensification of Coal Slurries Treatment and Dewatering
Processes", Australian Coal Conference
Verschuur, E.; Davis, G.R., "The Shell Pelletizing Separator: Key to
a Novel Process for Dewatering and De-Ashing Slurries of Coal Fines",
Holland, Australian Coal Conference
Wahler, William A., "Coal Refuse Regulations, Standards, Criteria and
Guidelines", Coal and the Environment Technical Conference,
October 1974
Wahlquist, Brent T., "Developing Strip Mine Reclamation Plans",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
W. A. Wahler & Associates, "Analysis of Coal Refuse Dam Failure—
Volume I", National Technical Information Service, Springfield,
Virginia, February 1973
W. A. Wahler & Associates, "Analysis of Coal Refuse Dam Failure—
Volume II", National Technical Information Service, Springfield,
Virginia, February 1973
W. A. Wahler & Associates, "Coal Mine Refuse Disposal Practice and
Technology", U.S. Bureau of Mines Contract No. SO 122084,
February 1974
W.A. Wahler s Associates, "Evaluation of Mill Trailings Disposal
Practices and Potential Dam Stability Problems in the Southwestern
United States", U.S. Bureau of Mines Contract No. SO 110520
Warnke, W.E., "Latest Progress in Sulfur, Moisture and Ash Reduction
Coal Preparation Technology", American Mining Congress Coal
Convention, Detroit, Michigan, May 1976
Weber, Walter J., Jr., "Physiochemical Processes for Water Quality
Control", Wiley Interscience, Division of John Wiley & Sons, Inc.,
New York, 1972
Wei-Tseng Peng, "The Jet-Cyclo Flotation Cell", The People's Republic
of China, Australian Coal Conference
573
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Wemco Division, "Manufacturer's Catalog", Envirotech Corporation,
Sacramento, California, 1974
Williams, Cyril H., Jr., "Planning, Financing and Installing a New
Deep Mine in the Beckley Coal Bed", Mining Congress Journal,
August 1974
Yancey, J.F.; Geer, M.R., "Behavior of Clays Associated with Low-Rank
Coals in Coal-Cleaning Processes", U.S. Bureau of Mines Report of
Investigations #5961
Yancey, J.F., "Determination of Shapes of Particles in Coal and Their
Influence on Treatment of Coal by Tables", AIME Translation, 94
Yancik, Joseph H., "Research to Improve Coal Mining Productivity",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1976
Yusa, M.; Suzuki, H.; Tanaka, S.; Igarashi, C., "Sludge Treatment Using
A New Dehydrator", Japan, Australian Coal Conference
574
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14. REMOVAL OF CONTAMINANTS FROM COAL
14.1 OVERVIEW
The combustion of coal results in the formation of
pollutants which include oxides of sulfur and nitrogen,
plus the elemental forms or compounds of beryllium,
chlorine, fluorine, arsenic, selenium, cadmium, mercury,
lead and other potential pollutants. Sulfur oxide,
nitrogen oxide and particulate air pollution emissions from
coal combustion exceeded 28 million metric tons in 1974.
Sulfur dioxide (SO-) is the pollutant of principal
concern. Annual SO^ emissions from coal combustion in
1974 were estimated to be 20.5 million tons. This repre-
sents 65% of the total SO- emissions for that year. On a
national basis the 5.3 million tons of NO emissions from
X
coal combustion represented 24% of the total 1974 NO
A
emissions. Emissions of other potentially hazardous
elements or compounds while not as large may present
environmental or health problems because of their concentra-
tion in process waste streams, concentration in the
environment or effects produced by prolonged exposure at
low concentrations. Coal-fired electric utility plants are
the major source of sulfur oxide air pollution in the
United States today. In 1974 the electric utilities burned
390 million tons of coal with an average sulfur content of
2.2 percent. The amount of coal consumed by electric
575
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utilities is anticipated to reach 500 million tons by 1980
and approximately a billion tons by the year 2000. It is
therefore imperative that sulfur oxide emissions be
controlled.
Only 14% of the 455 U. S. coals tested for physical
cleanability by the U. S. Bureau of Mines are capable of
meeting federal new source performance standards (NSPS) for
steam generators (1.2 Ib S02/10 Btu) as mined. Available
methods for controlling sulfur oxide emissions from
stationary combustion sources fall into the following
major categories:
The physical removal (coal cleaning) of pyritic
sulfur prior to combustion.
The removal of sulfur oxides from the combustion
flue gas.
Conversion of coal to a clean fuel by such
processes as gasification, liquefaction and
chemical extraction.
Physical and chemical coal cleaning processes are capable
of removing major quantities of pollution species (espe-
cially sulfur) prior to coal combustion. As discussed in
Chapter 2, sulfur exists in coal in two principal forms:
organic sulfur, which is bonded to the coal structure, and
inorganic sulfur, generally in the form of pyrite. U. S.
coals vary widely in the relative amounts of organic
and pyritic sulfur. Physical coal cleaning with equipment
normally used for removal of ash and mining residues is
capable of separating coal and pyritic sulfur. Chemical
cleaning is capable of removing both pyritic and organic
sulfur.
Of the 455 U. S. coals tested for cleanability by the
U. S. Bureau of Mines, it has been estimated that for a 1^
inch top size feed if physically cleaned to a 90% Btu
576
-------
recovery, 24% could meet NSPS. Physically cleaned at the
same top size and to the same Btu recovery, 35% are capable
of meeting a standard of 2.0 Ib SO-/10 Btu, while over 60%
*• C
are capable of meeting a standard of 4.0 Ib S09/10 Btu.
* c
Many states have emission standards as high as 4.0 Ib SO-/10
Btu. Thus, there may be a significant application of physical
coal cleaning to meeting state emission regulations.
Chemical coal cleaning is capable of higher levels of
desulfurization. Thus it potentially has a wider range of
applicability. In some instances, depending upon the coal,
the emission regulation and site specific considerations,
it may be the most cost effective method for SO- emission
control. However, for other cases, chemical coal cleaning
may not be competitive with either physical cleaning or
flue gas desulfurization. Figure 14-1 presents the
ranges of estimated costs and the degree of applicability
for different sulfur emission control strategies. As
indicated, of these three methods the physical removal of
pyritic sulfur is potentially the lowest cost and certainly
the most developed method technologically. However, as
stated in Chapter 2, the amount of total sulfur reduction
that may be obtained by physical methods is limited to
that quantity of the total sulfur content that is not
chemically bonded to the coal; i.e., the pyrite and sulfate
sulfur. Organic sulfur comprises from 30 to 70% of the
total sulfur of most coals. Sulfate sulfur content is
usually less than 0.05% and it is an oxidation product that
is readily removed during physical coal cleaning.
As discussed in detail in Chapter 7, the techniques
now widely used on a commerical basis for the removal of
these impurities include jigging, heavy media separation,
water-only cyclones, tabling and flotation. These methods
depend upon differences in physical and chemical properties
of the coal and impurities to achieve separation. Since
577
-------
100
90
80
w 70
o
u
-H 60
-U
tf
•a
a>
4J
-P
w
50
40
30
20
Capital
Operating
Gasification
Liquefaction
Chemical
Reaction
Physical
Coal Cleaning
Chemical
Leaching
60 70
Sulfur Control, %
80
90
100
Figure 14-1
Estimated Costs of Sulfur Removal
Potential of Different Emission Control Strategies
578
-------
1965 the EPA, the U. S. Bureau of Mines, the Bituminous Coal
Research, Inc. and others have cooperatively evaluated these
and other techniques for the selective removal of pyrite
from cpal. Some of the "other" techniques evaluated have
included thermal-magnetic separation, immiscible liquid
separation, selective flocculation, electrokinetic
separation and two-stage froth flotation. Techniques which
rely upon differences in specific gravities of the coal
and pyrite particles have been found to be the most commer-
cially viable for desulfurization. Froth flotation which
depends upon the selective adhesion of air bubbles to the
coal particles has also been found to be a useful commercial
technique.
Because some coals are more amenable than others to
sulfur removal by physical methods, studies have been
performed on U. S. coals to determine pyrite liberation
by size reduction and separation by specific gravity
differentials. The 455 samples tested to date are from
mines which provide more than 70% of the coal used in U. S.
utility boilers. The laboratory float-sink tests performed
in organic liquids of specific gravities ranging from 1.3
to 1.9 and size fractions from a minus 1% inches to a minus
14 mesh provide information on the pyritic sulfur which
can be removed from these coals.
The results of these float-sink or washability studies
indicate that the pyritic sulfur removal generally increases
with reduced coal particle sizes and specific gravities.
Crushing to finer sizes liberates more of the dense mineral
matter from the coal matrix and low media specific gravi-
ties allow more of this dense material to sink. At low
specific gravities a cleaner product is obtained; i.e., ash
ash and pyritic sulfur are decreased. However, this
clean product is obtained at reduced Btu recovery.
579
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Theoretically at very fine sizes a large percentage of the
pyritic sulfur could be released from the coal matrix and
separated without excessive Btu losses. This fact is
extremely important. It implies that to enhance sulfur
removal more of the coal must be crushed and processed
at finer sizes than historically practiced in coal
preparation. This will require modifications to current
processing plant design practices. These design changes
will necessarily incorporate techniques for improved fine
coal separation, dewatering and drying. Modified pollution
control and waste disposal techniques will also be required.
Table 14-1 presents data on the amount of pyritic
sulfur which can be removed from coal samples from six
regions by crushing to a top size of 3/8 inch and by
separation at a specific gravity of 1.6. It is important
to note that the pollutant potentials of the cleaned coals
represented by the data in column 5 are significantly
different. (The term "pollutant potential" is used
since it is assumed that all the sulfur contained in the
cleaned coal is converted and emitted as S02.) For
example the average S02 pollutant potential for the
Northern Appalachian, the Southern Appalachian and the
Eastern Midwest coal region samples are 2.7, 1.3 and 4.2
Ib S02/10 Btu, respectively.
14.2 WASHABILITY STUDIES
A washability analysis is an evaluation of those
physical properties of a coal which determine its
amenability to improvements in quality by cleaning. This
includes stage crushing to release impurities and specific
gravity fractionation to show the quality and quantity of
the cleaned product. A washability study is made by
testing the coal sample at preselected, carefully controlled
specific gravities. This is termed "float-sink" analysis
580
-------
Ul
oo
Table 14-1
Summary of the Physical Desulfurization Potential of Coals by Regionc
Cumulative Analyses of Float 1.60 Product
Percent
No. of
Region Samples
Northern
Appalachian
Southern
Appalachian
Alabama
Eastern
Midwest
Western
Midwest
Western
U.S. Total
227
35
10
95
44
44
455
Btu
Recovery
92
96
96
94
91
97
93
.5
.1
.4
.9
.7
.6
.8
Ash
8.0
5.1
5.8
7.5
8.3
6.3
7.5
Pyritic
Sulfur
0.85
0.19
0.49
1.03
1.80
0.10
0.85
Total
Sulfur
1
0
1
2
3
0
2
.86
.91
.16
.74
.59
.56
.00
Pounds
so2/io6
Btub
2.
1.
1.
4.
5.
0.
3.
7
3
7
2
5
9
0
Calorific
Content,
Btu per
Poundc
13
14
14
13
13
12
13
,766
,197
,264
,138
,209
,779
,530
SO Removal
Efficiency
Required for
NSPSd
in Percent
56
8
29
71
78
None
60
Summary of the composite product analyses for 3/8 inch top size, float-sink tested at 1.6
specific gravity.
Based upon the moisture free Btu value of the float coal and assuming all sulfur is converted
to SO_. Actual emissions will vary dep<
conversion efficiency of sulfur to SO .
to SO_. Actual emissions will vary depending on the as-fired coal moisture content and the
'Moisture free basis.
Values may require adjustment to account for the as-fired coal moisture content and efficiency
of sulfur conversion to SO2. NSPS - Federal New Source Performance Standards for Steam
Generators (1.2 Ib SO2/106 Btu).
Source: U.S.B.M. RI 8118 as modified by James Kilgroe USEPA in a paper entitled
"Physical and Chemical Coal Cleaning for Pollution Control"
-------
or specific gravity separation. Mixtures of organic liquids
are commonly used to obtain the desired specific gravities
of separation. Chemical analyses of the various specific
gravity fractions of the coal are used to compile the
washability data which indicate how well the coal can be
prepared.
14.2.1 Description of Testing Procedures (Float and
Sink Analysis)
The following information is quoted exactly or para-
phrased from the U. S. Bureau of Mines RI 8118 by J. A.
Cavallaro, M. J. Johnston and A. W. Deurbrouck as
published in 1976.
Collection of Samples
Face samples were collected from surface and deep
mines which were producing coal primarily for con-
sumption by electric utilities. In general, an
attempt was made to sample the largest utility coal
producing mines in the United States; therefore, the
455 coal mine samples reported in this publication
represent mines which provide more than 70 percent of
the annual utility coal production.
Face samples were collected according to the
procedure recommended by Fieldner and Selvigl and
Holmes^, except that the dimensions of each sample
cut were expanded to permit 600 pounds of coal to be
taken from the face. Partings and impurities were
not removed from the samples unless otherwise noted.
The face was cleared of loose coal or dirt for a
width of approximately 5 feet. Loose pieces of roof
were also taken down to prevent their falling into
the sample while it was being obtained. Within the
.Fieldner, A.C. & W.A. Selvig. Notes in the Sampling and
Analysis of Coal. Bureau of Mines Technical Paper
586, 1938, 48 pp.
2
Holmes, J. A. The Sampling of Coal in the Mine. Bureau
of Mines Technical Paper 1, 1918, 22 pp.
582
-------
cleaned off area on the face, the coal was cut from
the roof to the floor in a channel one inch deep and
about 3 feet wide to remove any altered or otherwise
inferior coal. The floor was then cleared and smoothed
and a sampling cloth was spread prior to collecting
the sample.
The actual channel sample was cut perpendicular to the
lay of the coalbed, approximately 10 inches deep and
wide enough to provide a sample of 600 pounds. For
example, for a 4-foot-thick coalbed a channel 30.5
inches wide would be collected. The exception to this
rule would be when a strip mine sample is obtained
where the overburden has been removed. In this case,
the depth and width of the channel would be equal.
For example, for the 4-foot-thick bed noted above,
the channel would be 17.5 inches deep by 17.5 inches
wide. The collected sample includes all partings and
other impurities occurring in the channel.
Sample Preparation
The 600 pound channel samples collected in the field
are loaded into steel drums and returned to the coal
preparation laboratory for processing. The sample
preparation procedure is outlined in the flowsheet
shown in Figure 14-2. Each sample to be tested is
air dried and then crushed to 1^ inch top size using
a single roll crusher. The sample is then coned,
long piled and shoveled into four pans, according to
ASTM specifications, and divided into two portions
by combining opposite pans.
One of the 1% inch by 0 portions is processed as is;
the other portion is crushed in a jaw mill to 3/8 inch
top size. This 3/8 inch by 0 material is then
riffled into two portions; one is processed as is
(3/8 inch by 0) and the other is crushed to 14-mesh
top size in a hammer mill and processed.
A head sample is riffled from the 14-mesh by 0 portion
for proximate analysis (moisture, ash, volatile matter
and fixed carbon) and for determination of calorific
value, fusibility of ash, free-swelling index,
Hardgrove grindability index and sulfur forms and
content (pyritic, organic and total). Since the
minus 100-mesh material represents such a small
percentage of the weight of the two coarser size
fractions analyzed, it is removed prior to float-sink
testing and is not presented in this report.
583
-------
Gross sample
crushed to
- inch top size
Long piled and divided
inches XO
Screened
'\^ inches X 100
mesh;
i— 100 mesh X 0
Screened
l£ inches X 0
crushed to
1-inch top size
o
Riffled
X 100 mesh
100 meshXO
crushed to
14-mesh top size
'/'/'//.
\4 mesh X 0
/,/,/, /, //.
Indicates float-sink tested
Figure 14-2
Flow Diagram Showing Preparation of Face Samples
Source: U. S. Bureau of Mines RI 8118
584
-------
The various sized fractions are then float-sink
tested at 1.30, 1.40 and 1.60 specific gravities
using CERTIGRAV, a commercial organic liquid of
standardized specific gravity; the solution tolerance
is ±0.001 specific gravity unit and is monitored
using a spindle .hydrometer. Those samples processed
by Commercial Testing and Engineering Co. were further
float-sink tested at 1.90 specific gravity.
The principle of float and sink testing procedure is
as follows: weighted amounts of the different size fractions
are added gradually and in small quantities to the liquid
of the lowest gravity. The total fraction which floats is
separated from the fraction which sinks. The liquid
absorbed by the coal is eliminated, if necessary, and the
procedure is repeated successively with liquids extending
over the desired range of specific gravities. The fraction
which sinks in the liquid of highest specific gravity is
also obtained. The weight and ash content of each fraction
are determined. The results are expressed as percentages
of the size fraction treated and are calculated also as
weighted percentages of the total sample treated, excluding
the dust. The results are usually set out graphically in
a series of curves.
For the two coarser sizes, the separation is ma.de in
a screen bottom container which is inserted in 10
gallon capacity vessels containing the organic liquid.
The sample is placed in the 1.30 specific gravity bath,
in small quantities to prevent entrapment, and is then
stirred and allowed to separate. The lighter specific
gravity coal fraction is removed from the surface of
the bath with a screen wire strainer; the heavier
specific gravity material settles to the container
bottom which is then raised above the liquid level
to drain. The container with the heavier specific
gravity material is then placed in the 1.40 specific
gravity solution and the process is repeated. This
is continued until the sample is separated into the
desired specific gravity fractions.
For the 14-mesh by 0 size fraction, the separation is
made in glass separatory flasks joined by standard
ground taper joints. After the sample separates, a
585
-------
stopper is passed through the float layer and inserted
into the neck of the separatory funnel. Both products
are filtered; the "floats" are dried and prepared for
analysis, while the "sinks" are reintroduced into
another separatory flask containing a heavier specific
gravity liquid and the float-sink procedure is
continued.
Upon completion of the float-sink testing, the specific
gravity fractions of the three sized samples are
analyzed for ash, pyritic sulfur and total sulfur
content. All chemical analyses are reported on a
moisture-free basis unless otherwise noted. Raw coal
moisture, as presented in the appendix tables, is the
moisture contained in the sample after being air dried
at the coal preparation laboratory. The air dry loss
is not included in the moisture determination. It is
felt that under normal conditions the moisture content
as reported here would closely simulate the moisture
content of the coal burned at the power plant.
Specific gravity separations of fine coal are particu-
larly difficult, especially with coals that are
porous and contain high inherent moisture contents,
because the heavy liquid used can penetrate the pores
and increase the apparent specific gravity of the coal.
This explains the unexpectedly low weight recoveries
noted occasionally for the float 1.30 specific gravity
fraction of the lower rank coal samples crushed to
14-mesh top size.
The float-sink data from the channel samples are not
to be construed as representing the quality of the
product loaded at the mine where the sample was taken,
but rather as indicating the quality of the bed in
that particular geographical location. Float-sink
data are based upon theoretically perfect specific
gravity separations that are approached but not
equalled in commercial practice.
14.2.2 Description of Testing Procedures (Total
Sulfur and Form of Sulfur)
The total sulfur content in a sample of coal may be
determined by any one of three methods according to ASTM
Testing Procedure D 3177-75. The procedures appear in the
following order:
586
-------
Eschka method
Bomb washing method
High-temperature combustion method.
The Eschka method consists of incinerating coal and
coke with Eschka mixture (2 parts of light calcined
magnesium oxide (MgO) and one part of anhydrous sodium
carbonate (Na2CC>3) . After allowing the contents to cool,
the contents are thoroughly washed with hot water; a small
quantity of hydraulic acid is added to make the washed
solution slightly acid and the sulfur is precipitated out
by the addition of a hot 10-percent solution of barium
chloride (BaCl22H20). After cooling and washing, the
filtered precipitate is ashed and weighed. The sulfur
content is calculated as follows:
Sulfur percent in the analysis sample equals:
(A-B) x 13.738
C
where:
A = grams of BaSO^ precipitated,
B = grams of BaSC>4 correction and
C = grams of sample used.
Total sulfur may also be determined in the washings
frora the oxygen bomb calorimeter after the calorimetric
determination. The U. S. Bureau of Mines has found that
the results from this method check closely with those of
the Eschka method. In addition, the bomb-washing methods
save considerable time over the Eschka method and is
therefore primarily used by the U. S. Bureau of Mines Coal
Analysis Laboratory. In this technique, the bomb is fired,
cooled and depressurized as specified. After washing with
distilled water and methyl orange until no acid reaction
is observed, the washings are collected and titrated with
587
-------
standard ammonia solution to obtain the acid correction for
the heating value. After boiling, washing and filtering the
resulting solution, hydrochloric acid is added and the
heated solution is precipitated with barium chloride as
described for the Eschka method. Again the sulfur content
is calculable by the formula:
(Weight of BaS04 - blank) x 13.74 _
Weight of sample
Percentage of Sulfur
Permissible difference of the same sample, same laboratory
follow:
Ultimate
Analysis of
Sulfur, percent
0-2
2-4
Over 4
Permissible differences,
percent
Eschka
Method
0.05
.08
.10
Bomb-
Washing
Method
0.10
.15
.20
In the high-temperature combustion method, a weighed
sample of coal is burned in a tube furnace at a temperature
of 1350° C. in a stream of oxygen. The sulfur oxides and
chlorine formed are absorbed in a hydrogen peroxide (H^O-)
solution yielding hydrochloric (HC1) and sulfuric (H-SO.)
acids. The total acid content is determined by titration
with sodium hydroxide (NaOH), and the amount of sodium
chloride (NaCl) resulting from the titration of the HC1
is converted to NaOH with a solution of mercuric oxycyanide
(Hg(OH)CN). This sodium hydroxide is determined titrimeti-
cally and used to correct the sulfur value which is
equivalent to the amount of H-SO, formed during the
combustion of the coal. The percent of sulfur is calculable
as follows:
588
-------
1.603 (F1(a-a1) -
s =
where :
S = percent sulfur in coal.
a = millilitre of NaOH solution used in
full determination.
a, = millilitre of NaOH solution used in
blank determination.
b = millilitre of H2S04 in full
determination .
b, = millilitre of H2S04 in blank
determination .
F, = normality of NaOH solution.
F- = normality of H_SO. solution.
W = grams of coal taken.
After the total sulfur content in a particular coal
sample has been determined, the three commonly recognized
forms of sulfur in coal (sulfate sulfur, pyritic sulfur
and organic sulfur) may be determined as defined in ASTM
Designation: D 2492-68 (reapproved 1975).
The sulfate sulfur is determined by extracting a
weighed sample of coal with dilute hydrochloric acid
followed by precipitation with barium chloride (BaCl»)
and weighing as barium sulfate. The sulfate sulfur is
soluble in dilute hydrochloric acid; pyritic and organic
sulfur are not. This procedure is summarized in U. S.
Bureau of Mines Bulletin "Methods of Analyzing and Testing
Coal and Coke" :
"Weigh out a 2.0000-gram sample, weighed to
0.1 mg, and place it in a 250-ml beaker. Add
3 ml of 1:3 ethyl alcohol and swirl to wet the
sample. Cover the sample carefully with 50 ml
of hydrochloric acid (1:3). Cover with a watch
glass and place on a hotplate to boil.
589
-------
At the end of 20 minutes, filter the contents
of the beaker, retaining the coal material left
on the filter, after washing six times with cold
water, for the pyritic sulfur determination. To
the filtrate add 10 ml of bromine water and heat
almost to boiling. Add 20 to 25 ml of 1:1 ammo-
nium hydroxide, and let stand on a hotplate for
20 minutes. Filter while hot, discarding the
residue left on the filter after washing five or
six times with hot water. Increase the volume of
the filtrate to 200 ml with distilled water.
Neutralize the filtrate with hydrochloric acid
(2:1) and add an excess of 5 ml, using methyl
orange indicator. Heat the solution to boiling,
add slowly 20 ml of hot 10 percent barium chlor-
ide solution, and allow to stand for several
hours. Filter and wash the precipitate with hot
water until free of chlorides, ignite the filter
paper, and weigh the barium sulfate. The weight
of barium sulfate, in grams, multiplied by 6.868
represents the percentage of sulfur combined as
sulfate in the coal."
Pyritic sulfur is determined by extracting a weighed
sample of coal with dilute nitric acid followed by titri-
metric determination of iron in the extract as a measure
of pyritic sulfur. The extraction process with the use
of nitric acid involves oxidation of ferrous iron to ferric
and sulfide sulfur to sulfate, both of which are soluble in
nitric acid. Because the extraction dissolves sulfate and
pyritic sulfur plus a small amount of organic sulfur, the
dissolved sulfur is not a reliable measure of pyritic sulfur.
Consequently, pyritic sulfur is obtained by determining the
amount of iron combined in the pyritic form which is equal
to the difference between nitric acid and hydrochloric acid-
solution iron.
The sample of coal used for the pyritic sulfur deter-
mination may be a separately weighed sample or the residue
from the hydrochloric acid extraction for sulfate sulfur.
If the residue is used, two acid extractions are carried
590
-------
out on the same sample, the nitric acid treatment being
applied to the coal residue from the hydrochloric acid
extraction for determination of sulfate sulfur. Determina-
tion of iron in the hydrochloric acid extract is unnecessary,
because iron in the nitric acid extract represents pyritic
iron. However, there are certain limitations to the use of
sulfate sulfur residue for determination of pyritic sulfur
in coal: if pyritic iron is high, the large sample required
for determination of small amounts of sulfate sulfur will
contain large quantities of iron and may require dilution;
the determination of pyritic iron cannot be carried out
until both extractions of sulfur have been completed.
According to U. S. Bureau of Mines testing procedures for
pyritic sulfur(Bulletin 533 USBM Office of Coal Research 1967)
"Macerate the coal residue and filter paper from
the hydrochloric acid separation in 100 ml of 25
percent by volume nitric acid and allow to stand,
with occasional stirring for 12 to 24 hours at
room temperature. Filter and discard the coal
residue after washing several times with cold
water. Add 3 ml of concentrated hyrdochloric
acid to the filtrate and evaporate to dryness on
a water bath. Dissolve the residue in 5 ml of
concentrated hydrochloric acid and 25 ml of water.
Pour this acid solution into a 250-ml beaker and
add 25 ml of hot ammonium hydroxide (1:1) making
sure that ammonium hydroxide is in excess. Filter
while hot and wash several times with hot water.
Sulfur in the filtrate is determined by the method
used for sulfate sulfur.
Dissolve the precipitate of ferric hydroxide off
the filter with the least possible quantity of
concentrated hydrochloric acid, added drop by
drop, and wash with small amounts of water. Heat
the acid solution contained in a 250-ml beaker
almost to boiling and add stannous chloride (10
grams of stannous chloride dissolved in 20 ml of
hot concentrated hydrochloric acid and diluted to
200 ml with water) drop by drop from a burette
until the solution is colorless, adding 3 or 4
drops in excess. Cool the solution rapidly and
591
-------
transfer it to a 600-ml beaker containing 250 ml
of cold water. Add 10 ml of a saturated solution
of mercuric chloride, stir the solution thoroughly,
then add 20 ml of titrating solution (144 grams of
manganeous sulfate, 1,040 ml of water, 280 ml of
sulfuric acid, 1.84 specific gravity, and 280 ml
of phosphoric acid, 1.71 specific gravity) and stir
until well mixed. Titrate at once with 0.02 N
potassium permanganate until the faintest pink color
lasts for 10 seconds. The number of milliliters of
0.02 N potassium permanganate used, multiplied by
0.0558, gives the percentage of pyritic iron in the
coal. Comparison is made with the gravimetric
determination of pyritic sulfur, and if the calcu-
lated percentage is lower than that obtained
directly, the calculated value is considered to be
the correct one."
The organic sulfur is determined by subtracting the
sum of the sulfate sulfur and pyritic sulfur from the total
sulfur as determined in accordance with ASTM Method D 3177—
"Test for Total Sulfur in the Analysis Sample of Coal and
Coke."
14.3 WASHABILITY DATA
As discussed in Chapter 11, the determination of the
preparation methods and the equipment needed to clean a
specific coal is determined by washability studies. The
washability study is an analysis or evaluation of the
physical properties of coal which determine its amenability
to improvements in quality by cleaning. The studies include
stage crushing to release trapped impurities and specific
gravity fractionation to show the quality and quantity of
the cleaned product. The washability studies are made by
testing the coal samples at preselected, carefully controlled
specific gravities (float and sink analysis). Detailed
chemical analyses of the various specific gravity fractions
of the coal are used to compile the washability data, e.g.:
592
-------
proximate analysis, ultimate analysis, calorific value, coal
ash composition (see Chapter 11).
Typical washability data is shown in the following
series of figures beginning with Table 14-2 General Wash-
ability data for the Upper Kittanning coal bed. Cumulative
yield, ash, pyritic sulfur and total sulfur contents are
displayed, showing theoretical yields and product quantities
at various specific gravities when samples of coal were
crushed to 1^ inch, 3/8 inch and 14 mesh top sizes. The
interpolated sulfur and yield data shown in the figure were
obtained as part of a computer program used by the U. S.
Bureau of Mines which provided theoretical data that show
at a glance the specific gravity of separation, the yield,
the ash and the pyritic sulfur content to be expected at
any desired total sulfur level.
Much more detailed washability data is available. For
example, Table 14-3 represents a screen analysis of the
Upper Kittanning Coal Bed showing the percent of total
weight, ash content, pyritic sulfur and total sulfur by
individual size fractions within each of two top size
categories as direct percentages and as cumulative percent-
ages. This information provides the data base needed to
analyze the impact of the size fractions on the preparation
plant.
Table 14-4 shows the general physical and chemical
properties of the Upper Kittanning Coal Bed. Tables 14-5
and 14-6 show the detailed washability analysis of the same
bed indicating the effects of stage crushing on the libera-
tion of pyritic sulfur.
The U. S. Bureau of Mines Report of Investigations
RI 8118 entitled Sulfur Reduction Potential of Coals of
the United States, by J. A. Cavallano, M. T. Johnston and
593
-------
Table 14-2
Typical Washability Data Plus Interpolated
Values'Provided by U. S. Bureau of Mines
STATE PA. (BITUMINOUS)
COUNTY CAMBRIA
TOP SIZE 1-1/2
INCHES
COALBED UPPER KITTANNING
3/8 INCH 14
CUMULATIVE fcASHABI
PRODUCT
FLCAT-1.30
FLCAT-1.4C
FLOAT-1.60
TOTAL
YIELD
8.2
70. S
88.4
1CO.C
ASH
1.7
5.6
7.8
11.6
PYRITIC
SULFUR
.04
.30
.77
2. 16
TOTAL
SULFLR
.63
.80
1.32
2.70
YIELD
15.4
73.9
86.7
1CO.O
MESH
LITY DATA, PERCENT
ASH PYRITIC
SULFUR
1.7 .04
5.0 .17
6.8 .35
12.0 2.28
TC TAL
SULFUR
.61
.65
.33
2.80
YIELD
11.0
71.3
88.0
100.0
ASH
1.7
4.2
6.1
11.5
PYRITIC
SULFUR
.03
.13
.21
2.22
TOTAL
SULFUR
.49
.55
.70
2.74
INTERPOLATED SULFUR CATA
TOTAL
SULFUR
.50
1.00
1.5C
2. CO
2.50
S.G. OF
SEP.
1.5C
YIELD
77.6
ASH
6.4
PYRITIC
SULFUR
.54
S.G. OF
SEP.
INTERPOLATED Y
YIELD
50. C
60.0
70. C
80.0
90.0
S.G. OF
SEP.
1.37
1.38
1.4C
1.49
ASH
3.6
4.5
5.5
6.7
PYRITIC
SULFUR
.21
.09
.28
.52
TOTAL
SULFUR
.74
.77
.78
1.C4
s.e. OF
SEP.
1.36
1.38
1.39
1.49
YIELC ASh
IELC CATA
ASH PYRITIC
SULFUR
2.7 .12
3.5 .14
4.5 .13
5.8 .25
PYRITIC
SULFUR
TOTAL
SULFUR
.63
.64
.65
7 *
S.G. OF
SEP.
1.32
S.G. OF
SEP.
1.36
I .38
1.40
1.49
YIELD
23.2
ASH
2.5
3.2
4.1
5.1
ASH
2.2
PYRITIC
SULFUR
.06
.09
.12
.17
PYRITIC
SULFUR
.05
TOTAL
SULFUR
.53
.54
.54
.62
un
SOURCE: RI 7633, "Sulfur Reduction Potential of the Coals of the
of Mines, 1972, by A. W. Deurbrouck.
;tat
Bureau
-------
Table 14-3
Screen Analyses of Upper Kittanning-Bed Coal
Size analysis
1-1/2 Inches Top Size:
Minus 1-1/2-plus 1-inch
Minus 1-plus 3/4-inch
Minus 3/4-plus 1/2-inch
Minus 1/2-plus 3/8-inch
Minus 3/8-plus 1/4-inch
Minus 1/4-inch-plus 28-mesh
Minus 28-plus 48-mesh
Minus 48-plus 100-mesh
Minus 100-plus 200-mesh
Minus 200-mesh
3/8 Inch Top Size :
Minus 3/8-plus 1/4-inch
Minus 1/4-inch plus 28-mesh
Minus 28-plus 48 mesh
Minus 48-plus 100 mesh
Minus 100-plus 200 mesh
Minus 200-mesh
Direct Percent
Weight
6.1
4.8
10.0
6.3
10.4
44.9
5.9
4.4
3.1
4.1
17.1
64.4
6.8
4.7
3.4
3.6
Ash
63.8
44.0
32.8
27.9
24.4
16.1
13.4
14.2
15.0
17.1
38.2
20.0
15.2
16.0
16.6
19.0
Pyritic
Sulfur
2.12
2.13
2.16
2.20
2.34
1.67
1.32
1.40
1.78
1.38
2.44
1.63
1.42
1.76
2.22
2.03
Total
Sulfur
2.20
2.42
2.56
2.72
2.78
2.20
1.88
2.10
2.47
2.10
2.73
2.13
1.94
2.35
2.74
2.47
Cumulative Percent
Weight
6.1
10.9
20.9
27.2
37.6
82.5
88.4
92.8
95.9
100.0
17.1
81.5
88.3
93.0
96.4
100.0
Ash
63.8
55.0
44.4
40.5
36.1
25.2
24.4
23.9
23.6
23.2
38.2
23.8
23.1
22.7
22.5
22.4
Pyritic
Sulfur
2.12
2.12
2.14
2.15
2.70
1.91
1.87
1.85
1.84
1.83
2.44
1.79
1.77
1.77
1.78
1.79
Total
Sulfur
2.20
2.29
2.42
2.49
2.57
2.36
2.33
2.32
2.33
2.32
2.73
2.25
2.23
2.23
2.25
2.26
-------
Table 14-4
Chemical and Physical Properties
of Upper Kittanning-Bed Coal*
Analyses
Raw Coal
Chemical analysis, percent:
Proximate;
Volatile matter
Fixed carbon
Ash
Total
Pyritic sulfur
Total sulfur
15.9
60.6
23.5
100.0
1.77
2.3
Physical analysis:
Hardgrove grindability index
Free swelling index
British Thermal Units
Fusibility of Ash F:
Initial deformation temperature
Softening temperature
Fluid temperature
91
8.5
11710
2480
2570
2680
*Moisture-free basis.
596
-------
Table 14-5
Detailed Washability Analyses of Upper Kittanning-Bed Coal
Showing the Effect of Crushing on the Liberation of Pyritic Sulfur (1-1/2 inches top size)
Product
1-1/2 by 3/8
Float - 1.30
1.35
1.40
1.45
1.50
1.60
1.70
1.80
1.90
2.00
2.20
2.40
2.60
2.80
3.30
Sink - 3.30
Direct Percent
Weight
35.9
4.1
28.9
12.5
7.6
4.4
4.7
1.8
1.0
0.8
0.5
2.5
6.0
7.1
15.9
1.0
1.2
Ash
3.6
6.5
11.9
16.7
20.9
27.0
34.4
42.7
46.7
51.0
67.0
74.8
84.8
90.6
63.9
62.8
Pyritic
Sulfur
.09
.35
1.09
1.71
2.31
3.61
3.27
4.43
6.24
7.14
3.17
2.11
2.45
1.01
25.32
32.50
Total
Sulfur
.72
.89
1.49
2.17
2.84
3.84
3.79
4.77
6.41
7.94
3.49
2.82
2.69
1.05
25.81
32.86
Cumulative Percent
Weight
35.9
4.1
33.0
45.5
53.1
57.5
62.2
64.0
65.0
65.8
66.3
68.8
74.8
81.9
97.8
98.8
100.0
Ash
3.6
6.1
7.9
9.0
9.9
11.2
11.8
12.3
12.7
13.0
15.0
19.7
25.4
36.0
36.3
36.7
Pyritic
Sulfur
.09
.32
.53
.70
.82
1.03
1.10
1.15
1.21
1.25
1.32
1.39
1.48
1.40
1.64
2.02
Total
Sulfur
.72
.86
1.03
1.20
1.32
1.51
1.58
1.62
1.68
1.73
1.79
1.88
1.95
1.80
2.04
2.41
-------
Table 14-5 (continued)
Detailed Washability Analyses of Upper Kittanning-Bed Coal
Showing the Effect of Crushing on the Liberation of Pyritic Sulfur (1-1/2-inches top size)
en
^D
00
Product
28 by 100
Float - 1.30
1.35
1.40
1.45
1.50
1.60
1.70
1.80
1.90
2.00
2.20
2.40
2.60
2.80
3.30
Sink - 3.30
Direct Percent .
Weight
15.7
42.44
26.30
9.31
4.22
2.23
2.17
1.07
.40
.34
.32
.57
.90
.91
6.18
.80
1.84
Ash
1.9
5.2
9.5
13.8
17.9
23.6
30.3
40.1
45.0
52.0
61.3
69.0
77.3
88.0
65.8
64.8
Pyritic
Sulfur
.07
.13
.28
.47
.76
1.26
2.38
4.08
5.02
5.91
5.83
4.11
3.80
1.32
24.68
38.24
Total
Sulfur
.62
.68
.85
1.02
1.31
1.77
2.84
4.54
5.37
6.19
6.12
4.17
3.82
1.33
25.43
40.30
Cumulative Percent
Weight ,
100.0
42.4
68.7
78.1
82.3
84.5
86.7
87.7
88.1
88.5
88.8
89.4
90.3
91.2
97.4
98.2
100.0
Ash
1.9
3.2
3.9
4.4
4.8
5.3
5.6
5.7
5.9
6.0
6.4
7.0
7.7
12.8
13.2
14.2
Pyritic
Sulfur
.07
.09
.12
.13
.15
. .18
.20
.22
.24
.26
.30
.33
.37
.43
.63
1.32
Total
Sulfur
.62
.64
.67
.69
.70
.73
.75
.77
.79
.81
.84
.88
.91
.93
1.13
1.85
-------
Table 14-5 (continued)
Detailed Washability Analyses of Upper Kittanning-Bed Coal
Showing the Effect of Crushing on the Liberation of Pyritic Sulfur (1-1/2-inches top size)
Product
3/8 by 28
Float - 1.30
1.35
1.40
1.45
1.50
1.60
1.70
1.80
1.90
2.00
2.20
2.40
2.60
2.80
3.30
Sink - 3.30
Direct Percent
Weight
48.4
36.2
29.5
7.5
4.0
2.1
3.0
1.1
0.7
0.6
0.5
1.2
1.7
2.0
7.4
1.0
1.5
Ash
3.3
7.0
11.8
16.8
20.9
27.2
33.0
38.9
44.3
48.2
63.2
72.6
79.9
89.8
60.0
63.7
Pyritic
Sulfur
.08
.23
.60
1.11
1.54
3.42
4.09
5.84
7.90
11.42
6.16
4.19
5.17
1.69
32.70
37.72
Total
Sulfur
164
.77
1.13
1.59
2.27
3.90
4.57
6.68
8.44
11.92
6.51
4.46
5.33
1188
33.37
39.58
1 Cumulative Percent
Weight
84.3
36.2
65.7
73.2
77.2
79.3
82.3
83.4
• 84.1
84.7
85.2
86.4
88.1
90.1
97.5
98.5
100.0
Ash
3.3
4.9
5.6
6.2
6.6
7.3
7.7
7.9
8.2
8.4
9.2
10.4
11.9
17.8
18.3
19.0
Pyritic
Sulfur
.08
.14
.19
.24
.27
.39
.43
.48
.53
.60
.67
.74
.84
.90
1.23
1.77
Total
Sulfur
.64
.69
.74
.78
.82
.93
.98
1.03
1.08
1.14
1.22
1.28
1.37
1.41
1.73
2.30
-------
Table 14-5 (continued)
Detailed Washability Analyses of Upper Kittanning-Bed Coal
Showing the Effect of Crushing on the Liberation of Pyritic Sulfur (1-1/2-inches top size)
(71
O
O
Product
1-1/2 by 0
Float - 1.30
1.35
1.40
1.45
1.50
1.60
1.70
1.80
1.90
2.00
2.20
2.40
2.60
2.80
3.30
Sink - 3.30
Minus - 100
Direct Percent
Weight
100.0
25.7
28.8
9.6
5.3
2.9
3.5
1.3
.8
.6
.5
1.6
3.1
3.6
10.3
.9
1.5
3.3
Ash
3.0
6.6
11.5
16.4
20.5
26.8
33.3
40.7
45.4
49.6
65.3
74.0
83.2
90.1
62.2
63.7
16.0
Pyritic
Sulfur
.08
.26
.78
1.34
1.86
3.30
3.48
5.04
6.92
9.24
4.43
2.74
3.22
1.27
28.92
36.27
1.74
Total
Sulfur
.63
.80
1.25
1.81
2.46
3.66
3.97
5.61
7.27
9.82
4.76
3.31
3.43
1.36
29.53
37.73
2.18
Cumulative Percent
Weight
100.0
25.7
54.5
64.1
69.4
72.3
75.8
77.1
77.9
78.5
79.0
80.6
83.7
87.3
97.6
98.5
100.0
-100.0
Ash
3.0
4.9
5.9
6.7
7.3
8.2
8.6
8.9
9.2
9.4
10.5
12.9
15.8
23.6
24.0
24.6
-24.3
Pyritic
Sulfur
.08
.18
•; .27
.35
.41
.54
.59
.64
.69
.74
.81
.88
.98
1.01
1.28
1.79
i71.79
Total
Sulfur
.63
.72
.80
.88
.94
1.07
1.12
1.16
1.21
1.26
1.33
1.40
1.48
1.47
1.74
2.27
-'2.27
I/ These are cumulative values for the float-and-sink plus the minus 100 mesh material.
-------
Table 14-6
Detailed Washability Analyses of Upper Kittanning-Bed Coal
Showing the Effect of Crushing on the Liberation of Pyritic Sulfur (3/8 inch top size)
Product
3/8 by 28
Float - 1.30
1.35
1.40
1.45
1.50
1.60
1.70
1.80
1.90
2.00
2.20
2.40
2.60
2.80
3.30
Sink - 3.30
Direct Percent
Weight
84.5
22.4
33.2
9.4
5.1
2.5
3.6
1.1
0.8
0.6
0.4
1.8
2.7
2.8
11.1
1.0
1.5
Ash
2.7
6.4
11.8
17.0
21.0
27.7
33.8
41.4
47.5
50.6
67.2
74.8
81.0
90.4
62.3
63.2
Pyritic
Sulfur
.06
.19
.57
.96
1.48
2.70
3.62
4.62
6.13
8.78
3.89
2.61
3.33
1.11
26.47
37.52
Total
Sulfur
.58
.68
1.03
1.55
1.91
3.19
4.08
4.80
6.13
9.10
4.11
3.09
3.96
1.33
28.15
38.97
Cumulative Percent
Weight
84.5
22.4
55.6
65.0
70.1
72.6
76.2
77.3
78.1
78.7
79.1
80.9
83.6
86.4
97.5
98.5
100.0
Ash
2.7
4.9
5.9
6.7
7.2
8.1
8.5
8.8
9.1
9.3
10.6
12.7
14.9
23.5
23.9
24.5
Pyritic
Sulfur
• .06
.13
.20
.25
.29
.41
.45
.49
.54
.58
.65
.72
.80
.83
1.10
1.70
Total
. Sulfur
.5.8
.63
.69
.75
.79
.91
.95
.99
1.03
1.07
1.14
1.20
1.29
1.29
1.57
2.13
-------
Table 14-6 (continued)
Detailed Washability Analyses of Upper Kittanning-Bed Coal
Showing the Effect of Crushing on the Liberation of Pyritic Sulfur (3/8 inch top size)
en
o
to
Product
28 by 100
Float - 1.30
1.35
1.40
1.45
1.50
1.60
1.70
1.80
1.90
2.00
2.20
2.40
2.60
2.80
3.30
Sink - 3.30
Direct Percent
Weight
15.5
42.2
25.8
8.7
4.3
2.0
2.3
1.0
0.5
0.4
0.3
0.5
1.6
1.1
6.4
1.0
1.9
Ash
2.0
5.3
9.8
14.5
19.6
24.1
31.4
39.3
46.0
52.2
60.9
72.4
82.0
88.6
67.0
64.8
Pyritic
Sulfur
.05
.14
.29
.53
1.36
1.34
2.46
3.73
4.91
5.45
5.42
2.85
2.69
1.15
22.06
38.87
Total
Sulfur
.61
.73
.91
1.02
1.88
1.77
2.78
4.11
5.02
5.91
5.64
2.98
2.72
1.15
22.13
40.73
Cumulative Percent
Weight
100.0
42.2
68.0
76.7
81.0
83.0
85.3
86.3
86.8
87.2
87.5
88.0
89.6
90.7
97.1
98.1
100.0
Ash
2.0
3.2
3.9
4.5
4.9
5.4
5.7
5.9
6.1
6.2
6.5
7.7
8.6
13.9
14.4
15.4
Pyritic
Sulfur
.05
.08
.10
.12
.15
.19
.21
.23
.25
.27
.30
.35
.38
.43
.65
1.38
Total
Sulfur
.61
.65
.68
.70
.73
.75
.78
.80
.82
.83
.86
.90
.92
.93
1.16
1.91
-------
Table 14-6 (continued)
Detailed Washability Analyses of Upper Kittanning-Bed Coal
Showing the Effect of Crushing on the Liberation of Pyritic Sulfur (3/8 inch top size)
Product
3/8 by 0
Float - 1.30
1.35
1.40
1.45
1.50
1.60
1.70
1.80
1.90
2.00
2.20
2.40
2.60
2.80
3.30
Sink - 3.30
Minus 100
Direct Percent
Weight
100.0
25.4
32.0
9.3
5.0
2.4
3.4
1.1
.8
.6
.4
1.6
2.5
2.5
10.4
1.0
1.6
7.8
Ash
2.5
6.3
11.5
16.6
20.8
27.3
33.4
41.1
47.3
50.8
66.8
74.5
81.0
90.2
63.0
63.4
18.2
Pyritic
Sulfur
.06
.18
.53
.90
1.46
2.56
3.44
4.52
6.00
8.35
3.96
2.63
3.28
1.11
25.77
37.77
2.11
Total
Sulfur
.58
.68
1.01
1.47
1.90
3.03
3.88
4.72
6.01
8.69
4.18
3.07
3.87
1.31
27.29
39.29
2.60
Cumulative Percent
Weight
100.0
25.4
57.4
66.7
71.7
74.1
77.5
78.6
79.4
80.0
80.4
82.0
84.5
87.0
97.4
98.4
.100.0
- 100.0
Ash
2.5
4.6
5.6
6.3
6.8
7.7
8.1
8.4
8.6
8.9
10.0
11.9
13.9
22.0
22.5
23.1
-22.8
Pyritic
Sulfur
.06
.13
.18
.23
.27
.37
.42
.45
.49
.53
.60
.66
.74
.78
1.03
1.61
-X1.66
Total
Sulfur
.58
.64
.69
.74
.78
.88
.92
.96
.99
1.03
1.09
1.15
1.23
1.24
1.51
2.10
-2.14
— These are cumulative values for the float-and-sink plus the minus 100 mesh material.
-------
A. W. Deurbrouck, published in 1976 represents the results
of washability studies of 455 raw coal channel samples with
special emphasis on sulfur reduction. The 455 samples
represent 70% of the total annual utility coal production
sources for the United States.
The analysis of these samples reported on by the U. S.
Bureau of Mines have been compiled specifically to show
what effect size reduction and specific gravity fractiona-
tion have on the liberation and subsequent removal of
pyritic sulfur and other impurities. According to the U. S,
Bureau of Mines, the "cumulative weight and Btu recovery,
Btu per pound, ash, pyritic sulfur, total sulfur and pounds
S09 emission per million Btu levels are given showing
£*
gravities when the coal samples were crushed to \h inch,
3/8 inch and 14 mesh top sizes. The Btu per pound values
for the float 1.60 specific gravity products and the total
or raw coal products were obtained by actual analysis;
those of the float 1.30, 1.40 and 1.90 specific gravity
products were obtained by interpolation from a plot of
cumulative ash versus cumulative Btu per pound. The pounds
SO- emission per million Btu were calculated using the
corresponding Btu per pound (moisture-free basis) and total
sulfur content (moisture-free basis) and assumes that all
of the sulfur in the coal goes out of the stack as SO .
Actual emissions may vary because as-fired coals will con-
tain some moisture and all of the sulfur may not go out the
stack as SO ." All chemical analyses are reported on a
S
moisture-free basis. Raw coal moisture is the moisture
contained in the sample after being air dried at the coal
preparation laboratory based on the assumption that the
moisture content thus arrived at and reported would closely
simulate the moisture content of the coal burned at the
selected power plants.
604
-------
In addition, the samples collected and analyzed by
the U. S. Bureau of Mines are broken down into six regions
(Northern Appalachian, Southern Appalachian, Alabama Region,
Eastern Midwest Region, Western Midwest Region and Western
Region) refined and shown in Chapter 20. A sample of the
data display is shown in Table 14-7.
Tables 14-8, 9, 10 and 11 are statistical evaluations
of the composited washability data as displayed in Table 14-7.
The data for each sample and a composite of all the samples
collected for each individual coalbed, or a composite of all
the samples collected for all the coalbeds of a region,
showing the effect on ash, pyritic sulfur and total sulfur
contents when crushing the coal to three top sizes, 1%
inches, 3/8 inch and 14 mesh are included. Average values
are given plus standard deviation (sigma) values. Average
values are the arithmetic means of the data involved in
computing any given average. Because the number of pieces of
data involved in the computation of an average gives one
measure of credence of the average, this number is shown in
all output. Sigma values are given to show the spread of
the data about the average. This sigma is the standard
deviation. For a normal distribution, 68 percent of the
cases should fall between the "average" (X), ±s; 95 percent
of the cases between the "average" X ± 2s, and 99.7 percent
of the cases between the "average" X ± 3s. Thus, it is
desirable to have "N," the number of samples, large and s,
"sigma," as small as possible.
Specifically Table 14-8 is a sample projected.by
percent weight recovery of a coal sample of a particular
coal bed showing the effects of stage crushing and gravi-
metric separation on the specific coal. Individual values
are presented for samples crushed to 1% inch top size,
3/8 inch top size and 14 mesh top size for each of the six
605
-------
Table 14-7
Sample Washability Data from
U. S. Bureau of Mines RI-8118
STATE: Pennsylvania (Bituminous)
COUNTY: Cambria
COALBED: Lower Kittanning
RAW COAL MOISTURE: .8%
CUMULATIVE WASHABILITY DATA
en
o
SAMPLE CRUSHED TO PASS 1-1/2 INCHES
Product
Float -. 1.30
Float - 1.40
Float - 1.60
Total
EPA Standard
Recovery, %
Weight
61.0
85.6
94.1
100.0
61.9
BTU
64.4
89.0
96.2
100.0
65.2
BTU/LB
15073
14858
14611
14288
15068
Ash,%
3.3
4.7
6.3
8.4
3.3
Sulfur,%
Pyritic
.15
.32
.49
1.31
.15
Total
.90
1.05
1.18
2.01
.90
LB SO /M BTU
1.2
1.4
1.6
2.8
1.20
SAMPLE CRUSHED TO PASS 3/8 "iNCH
Float - 1.30
Float - 1.40
Float - 1.60
Total
EPA Standard
65.3
87.1
93.3
100.0
90.1
69.1
90.7
96.0
100.0
93.6
15227
14996
14811
14396
14960
2.3
3.8
5.0
7.7
4.1
.20
.29
.39
1.19
.31
.81
.88
.97
1.81
.90
1.1
1.2
1.3
2.5
1.20
-------
• Table 14-7 (continued)
Sample Washability Data from
U. S. Bureau of Mines RI-8118
SAMPLE CRUSHED TO PASS 14 MESH
Product
Float - 1.30
Float - 1.40
Float - 1.60
Total
EPA Standard
Recovery, %
Weight
59.2
85.3
92.6
100.0
88.9
BTU
63.4
89.7
96.1
100.0
92.9
BTU/LB
15274
15012
14811
14272
14913
Ash,%
2.0
3.7
5.0
8.5
4.3
Sulfur, %
Pyritic
.09
.24
.35
1.29
.36
Total
.83
.85
.94
1.90
.89
LB SO /M BTU
1.1
1.1
1.3
2.7
1.20
-------
Table 14-8
O
03
COALBED: LOWER KITTANNING
STATE: PA
RAW COAL MOISTURE.PERCENT:
.7
ASH.PERCENT
RAW: 31.3 SIGMA: o.o
PYRITIC SULFUR,PERCENT
RAW: 3.so SIGMA: O.o
TOTAL SULFUR,PERCENT
RAW: 4.63 SIGMA: o.o
WEIGHT
RECOVERY
50.0
60.0
70.0
80.0
90.0
100.0
50.0
60.0
70.0
80.0
90.0
100.0
50.0
60.0
70.0
80.0
90.0
100.0
WEIGHT
RECOVERY
50.0
60.0
70.0
80.0
90.0
100.0
50.0
60.0
70.0
80.0
90.0
100.0
50.0
60.0
70.0
bO.O
90.0
100.0
NO OF
SAMPLES
1
1
1
1
1
1
1
1
1 '
1
1
1
NO OF
SAMPLES
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
AVERAGE SIGMA
4.1
5.2
7.0
10.1
15.1
31.7
3,6
4.5
6,2
9,1
14. 1
21.0
3.2
4.5
6.6
10.0
14.9
21.3
BTU
RAW:
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
RECOVERY
100.0
AVERAGE SIGMA
61.7
73.0
83.5
91.9
97.3
100.0
61.4
72.9
«3.5
92.1
97.6
100.0
62.0
73.3
83. <•
91.6
V7.1
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
REDUCTION
81.2
76.0
67. a
53.3
30.6
0.0
82.7
73.3
70.7
56.7
33.0
0.0
84.8
78.9
68.9
53.0
30.0
0.0
, PERCENT
SIGMA: 0.0
DEDUCTION
38.3
27.0
16. S
8.1
2.7
0.0
38.6
2?.l
16.5
7.9
2.".
0.0
38.0
26. a
16.6
8.4
2.9
0.0
SIGMA
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
SIGMA
0.0
0.0
0.0
0.0
0.0
o.o
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
AVERAGE SIGMA REDUCTION SIGHA
.16 0.0 95.9 0.0
.37 0.0 90.4 0.0
.76 0.0 80.5 0.0
1.44 0.0 63.1 0.0
2.48 0.0 36.2 0.0
3.89 0.0 0.0 0.0
.29 0.0 92.5 0.0
.31 0.0 91.9 0.0
.55 0.0 85.8 0.0
1.12 0.0 71.1 0.0
2.23 0.0 42.3 0.0
3.87 0.0 0.0 0.0
.26 0.0 93.5 0.0
.28 0.0 93.0 0.0
.53 0.0 86.9 0.0
1.16 0.0 71.3 0.0'
2.34 0.0 42.1 0.0
4.04 0.0 0.0 0.0
BTU PER POUND
RAW: 11956 SIGMA: o
AVERAGE SIGMA (INCREASE SIGMA
14i63 0 22 0
14435 0 21 0
14196 0 19 0
13492 0 13 0
12695 060
11U99 000
14656 0 22 0
14bJl 0 21 0
14323 0 19 0
13661 0 13 0
1283S 060
12009 0 00
14670 0 22 0
14540 0 21 0
14249 0 19 0
13549 0 13 0
12755 060
11962 000
AVERAGE SIGMA REDUCTION
1.17
1.20
1.58
2.24
3.25
4.59
1.13
1.15
1.37
1.92
3.00
4.58
1.10
1.10
1.36
1.97
3.10
4.73
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
POUNDS
RAW:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
OF
7.7
AVERAGE SIGMA
1.6
1.6
2.2
3.4
5.2
7.7
1 .5
1.5
1.9
2.9
4.8
7.6
1.5
1.5
1.9
2.9
5.0
7.9
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
74.5
73.9
65.6
51.2
29.3
0.0
75.4
74.9
70.0
58.1
34.5
0.0
76.7
76.7
71.3
58.2
34.2
0.0
S02/M UTu
SIGMA:
SIGMA
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
^REDUCTION SIGMA
79.3
79.3
70.9
55.6
31.9
0.0
80.2
80.0
74.7
61.8
36.7
0.0
81.0
81.1
76.1
62.7
37.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
-------
criteria: percent of ash, percent of pyritic sulfur,
percent total sulfur, percent Btu recovery, Btu per pound
and pounds of S09 per million Btu. For example, reviewing
&
Table 14-8, if the particular coal shown is cleaned by
physical methods with a yield of 50% by weight at a top
size of 1% inch, then:
The ash content is reduced from 21.7% to
4.1 (a reduction of 81.2%),
The pyritic sulfur content is reduced from
3.89% to 0.16% (a reduction of 95.9%),
The total sulfur content is reduced from
4.59% to 1.17% (a reduction of 74.5%),
The Btu recovery is reduced from 100% to
61.7% (a reduction of 38.3%),
However, the Btu per pound increases from
11899, to 14563 (an increase of 22%) and
The pounds of SO- per million Btu are
reduced from 7.7 to 1.6 (a reduction of
79.3%).
For this particular coal, following the table through to
final crushing to pass 14 mesh yields little further
significant reduction in total sulfur and only a 0.1%
reduction in pounds S02 per million Btu.
Table 14-9 shows the effects of crushing on liberation
of impurities by displaying the quality of theoretical
products obtained from cumulative interpolated washability
data at 50-, 60-, 70-, 80-, 90- and 100-percent Btu recovery
levels. The data are arranged and read the same as for
Table 14-8.
Table 14-10 shows the effects of crushing on liberation
of impurities by displaying the quality of theoretical
products obtained from cumulative interpolated washability
data at specific total sulfur levels beginning at 2.2 and
dropping down to 1.2 percent.
609
-------
COALBEO: LOWER KITTANN1NG
STATE: PA
RAM COAL MOISTURE.PERCENT:
Table 14-9
.7
WEIGHT.PERCENT
RAW:100.0 SIGMA: o.o
ASH.PERCENT
RAW: 21.3 SIGMA: o.o'
PYRITIC SULFUR.PERCENT
RAW: 3.93 SIGMA: o.O
BTU NO OF AVERAGE
RECOVERY SAMPLES
50.0
60.0
70.0
30. 0
90.0
100.0
50.0
60.0
70.0
80.0
90.0
100.0
40.3
08. j nnfi_c. ^nL/jr-TC-U
14682
14573
14064
14300
13032
11899
-SAMPLE CRUSHED
14770
14665
14557
14032
13667
12009
SAMPLE CRUSHED
147UO
10683
10571
10373
13083
11962
I u r-ny^
0
0
0
0
0
0
TO PASS
0
0
0
0
0
0
TO PASS
0
0
0
0
0
0
23 0
22
21
20
12
0
3/8 INCH
23
22
21
20
13
0
10 MESH
23
22
21
20
12
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
2
3
7
1
1
1
1
2
7
1
1
1
1
3
7
.5
.6
.4
.0
.5
.7
.4
.5
.0
.8
.9
.6
.4
.5
.6
.7
.1
.9
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.6
81
79
81
74
54
0
81
80
81
76
61
0
81
81
80
78
60
0
.1
.4
.2
.2
.7
.0
.7
.3
.1
.8
.5
.0
.9
.1
.3
.1
.3
.0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
-------
Table 14-10
COALBEDi LOWER KITTANNIN6
STATE: PA
RAW COAL MOISTURE.PERCENT!
.7
WEIGHT.PERCENT
RAWI100.0 SIGMA! 0.0
ASH,PERCENT
RAW! 21.3 SIGMA! 0.0
PYRITIC SULFUR.PtRCENT
RAW! 3.93 SIGMA! 0.0
TOTAL NO OF
SULFUR SAMPLES
1.2 i
1.4 1
1.6 1
1.8 1
2.0 1
2.2 i
1.2 1
1.4 1
1.6 1
1.8 1
2.0 1
2.2 1
1.2 1
1.4 1
1.6 1
1.8 1
2.0 1
2.2 1
AVERAGE
54.8
68.0
70.3
74.7
78.6
82.2
60.5
70.6
77.4
83.5
88.9
93.6
67.0
71.2
77.5
83.2
88.3
92.8
SIGMA
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
.0.0
0.0
0.0
REDUCTION SIGMA
45.2
32.0
29.7
25.3
21.4
17.8
39.5
29.4
22.6
16.5
11.1
6.4
33.0
28.8
22.5
16.8
11.7
7.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0,0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
AVERAGE SIGMA
•.SAMPLE CRUSHED TO
5.0 0.0
6.3 0.0
7.2 0.0
8.0 0.0
8.9 0.0
9.9 0.0
4.9 0.0
6.4 0.0
7.7 0.0
d.V 0.0
10.1 0.0
11.3 0.0
5.5 0.0
7.1 0.0
8.5 0.0
9.9 0.0
11.3 0.0
12.6 0.0
REDUCTION SIGMA
AVERAGE
SIGMA
REDUCTION SIGMA
76.6 0.0
70.6
66.4
62.5
58.1
53.7
PASS 3/8
77.2
70.0
64.1
5H.2
52.4
47.0
PASS 14
74.3
66.8
60.2
53.4
47.0
41.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
.36
.59
.79
.98
1.18
1.39
.37
.58
.79
.99
1.20
1.41
.38
.58
.77
.96
1.16
1.36
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
90.9
85.0
80.0
75.1
69.9
64.8
90.7
85.3
80.0
74.7
69.4
64.1
90.3
85.4
80.5
75.6
70.5
65.4
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
STU HECOVtwr, PERCENT
8AWI100.0 SIGMA! 0.0
BTU PER POUND
RAW! 1(956 SIGMA!
POUNDS OF S02/M UTU
RAW! 7.7 SIGMAI 0.0
TOTAL NO OF AVERAGE
SULFUR SAMPLES
1.2 1 66.7
1 .4 1 81.9
1.6 1 83.7
1 .8
2.0
2.2
1.2
1.4
1.6
1 .8
2.0
2.2
1.2
1.4
l.b
88. 1
91 .9
9S. 3
73.1
84.0
90.9
97.0
97.2
97.4
80.9
H-..S
90.6
1.8 1 96.1
2.0 1 yt>.<.
2.2 1 -vb.o
SIGMA
0.0
0.0
.0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
REDUCTION SIGMA
33.3
18. 1
16.3
11.9
8.1
4.7
26.9
16.0
9.1
3.0
2.8
2.6
19.1
IS.b
9.4
3.9
3.6
3.«.
0.0
0.0
0.0
0.0
0.0
0.0
o.o
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
o.n
AVERAGE SIGMA
14530
14330
141B7
14037
13884
13731
14S44
14JOS
14138
1J995
13852
13709
144S9
14206
14054
13920
1 J'86
1 Jttbl
TO
0
0
0
0
0
0
TO
0
0
0
0
0
0
TO
0
0
0
0
0
0
tlNCREASE SIGMA
AVERAGE
SIGMA
«REDUCTION SIGMA
21 0
19
18
17
16
14
PASS 3/fi
21
19
18
17
IS
14
PASS 14
20
18
1 7
16
15
14
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1.6
1.9
2.3
2.6
3.0
3.3
1.6
2.0
2.3
2.7
3.1
3.4
1.6
2.0
2.3
2.6
2.9
3.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
79.0
75.1
70.6
66.1
61.6
57.0
79.1
74.6
69.8
65.1
60.5
55.8
78.7
74.8
70.7
66.6
62.4
58.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
-------
Table 14-11 shows the effect of crushing on liberation
of impurities by displaying the quality of theoretical
products obtained from cumulative interpolated washability
data on specific, theoretical pounds of S0? emissions per
million Btu fired.
Generally, the data presented in RI 8118 show that
as the recoveries increased, the ash, pyritic sulfur, total
sulfur, weight, and pounds of S02 imission per million Btu
also increased. However, the Btu per pound decreased since
the ash content increased. As the sample was crushed, more
impurities were released and readily separated. That is,
the ash, pyritic sulfur, total sulfur, weight recovery and
pounds of S02 emission per million Btu generally decreased
while the Btu per pound increased when the sample was
crushed to the finer top sizes and the higher specific
gravity material was removed.
Figure 14-3 is a nomograph showing the S02 emissions
which will result from burning coals of various sulfur and
Btu contents. When using the nomograph or the formula
shown therein, it is important to maintain consistency and
to be sure that both the Btu per pound and sulfur values
are on an as received, moisture-free or moisture-and-ash
free basis. For example, a coal containing 0.8 percent
sulfur and 13,100 Btu per pound could meet the EPA SO,,
emission standard; however, a coal of the same sulfur
content but containing only 10,500 Btu per pound would
produce 1.5 pounds of S02 per million Btu and would there-
fore be out of compliance.
The following summary based on all of the 455 samples
is taken directly from RI 8118:
"The 455 raw coal samples averaged 14.9 percent
ash, 1.91 percent pyritic sulfur, 3.02 percent
total.sulfur and 12,574 Btu per pound, which
612
-------
E mission
'iullur, IbSOz/MM Jtu ' COlOMt.c volue
pi?r(.ent B'vj / Ib • 10^
100
9 0
8.0
7.0
6 0
5.0
4.0
3.0-
2.0-
1.5-
1 0-
0.9-
0 8-
07-
06-
05-
0.4-
0.3-
1.2-
-^
-25.0
•200
• 15.0
• 12.0
Emission , Ib SOj /MM Btu =
• 9.0 20 » Sulfur , percent
0 0
' Colorific volue, Btu/lb «IO"3
•6.0
• 50
• 4.0
3.0
20
1 5
— 1.2 EPA emission standoid
09
07
0.5
0.375
• 80
• 8 5
- 9.0
• & 5
• 10 0
• 10 5
•110
-M5
• 12 0
12 5
130
13 5
14 0
14 5
15 0
15 5
16.0
Figure 14-3
Nomograph Relating Sulfur Content and Calorific
Value in Coals to Pounds of SO Emission per Million Btu
would produce 4.9 pounds S02/MM Btu fired at the
power plant. The raw coal sulfur contents averaged
63 percent pyritic sulfur and 37 percent organic
sulfur.
The ash, pyritic sulfur, total sulfur and heating
value contents varied considerably as would be
expected when washability data of coals from various
regions of the United States are evaluated. This
is evidenced by the large sigma values for each of the
parameters evaluated.
Figure 14-4 shows that significant reduction of
impurities can be obtained, especially ash and
613
-------
c
o>
u
O
D
Q
UJ
cr
CD
2
5
o
en
CO
60
50
40
30
20
I
14 mesh
1.30 1.40 1.50 1.60 1.30. 1.40 1.50 1.60
SPECIFIC GRAVITY OF SEPARATION
Total U.S. (455 samples)
c
a;
o
O
H-
O
D
Q
UJ
or
or
CO
Figure 14-4
The Effect of Crushing to 1 1/2 inch, 3/8 inch and 14-mesh Top Size on the
Reduction of Ash, Pyritic Sulfur, Total Sulfur and Pounds SO2 Emission per
Million Btu at Various Specific Gravities of Separation for All U0SU Coals
614
-------
pyritic sulfur contents, by crushing and gravimetric
separation.
Figure 14-5 shows that only 14 percent of raw coal
samples as mined could meet the current EPA SO-
emission standard of 1.2 pounds SO^/MM Btu.
100
c
01
u
w
1>
Q.
CO
U
_l
0.
2
4
to
LJ
Z
i
I I I I
Product
a Row cool
b I 'A,- inch
top size ,
90% Btu rec
c 14 —mesh
top size ,
50% Btu rec
Samples meeting
EPA stondord,%
14
24
32
_L i i I L I I I I
10 12 14 16
LB S02/MM Btu
18
20
22
24
Figure 14-5
Percent of All U.S. Coal Samples Meeting the Current EPA
Standard of 1.2 Pounds SO /MM Btu with no Preparation, Curve
a; Compared With Those Crushed to I3! inch Top Size at a Btu
Recovery' of 90 Percent,Curve b; and Those Crushed to 14 mesh
Top Size at a Btu Recovery of 50 Percent, Curve c, and
Separated Gravimetrically.
615
-------
Twenty-four percent of the samples would meet the
standard at a 90 percent Btu recovery when crushed
to 1^3 inch top size, while 32 percent would meet
the standard at a Btu recovery of 50 percent when
crushed to a 14-mesh top size.
The composite data (Table 14-1) show if all the coals
were upgraded at a specific gravity of 1.60, the analyses
of the clean coal products of the various regions would
range on the average from 5.1 to 8.3 percent ash, 0.10
to 1.80 percent pyritic sulfur, 0.56 to 3.59 percent toal
sulfur, 12,799 to 14.264 Btu per pound and would produce
0.95 to 5.5 pounds of S02/MM at Btu recoveries ranging
from 91.7 to 97.6 percent. The corresponding SO-/MM
removal efficiencies required to comply with the current
EPA emission regulations of 1.2 pounds SO-/MM Btu would
range from 0 to 78 percent.
616
-------
REFERENCES AND/OR ADDITIONAL READING
AMAX Henderson, "An Experiment in Ecology", Editorial Alert - 1974,
Mountain Empire Publishing Company
American Society for Testing Materials, "Standard Methods for (1)
Collection of a Gross Sample of Coal, (2) Preparing Coal Samples for
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Bituminous Coal Research, Inc., "An Evaluation of Coal Cleaning
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1970, BCR Report L-404, April 1971, BCR Report L-464, April 1972
Bluck, W.V. & Norton, G., "High Intensity Fine Coal Flotation",
American Mining Congress Coal Convention, Pittsburgh, Pennsylvania,
May 1975
British Coke Research Association, "Methods for the Float and Sink
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January 1952
Brobst, Donald A. & Pratt, Walden P. (Editors), "United States
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U.S. Government Printing Office, 1973
Burden, R.G.; Booth, R.W.; Mishra, S.K., "Factors Influencing the
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Australia, Australian Coal Conference
Carter, R.P.; Wilkey, M.L.; Johnson, D.O.; Kennedy, A.S., "Coal
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Casali, J.T., "Heat Drying Sludge from Ponds", American Mining Congress
Coal Convention, May 5-8, 1974
Cassady, Jon M., "Obstacle Course for Permits and Approval", American
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Cavallaro, J.A.; Deurbrouck, A.W.; Baker, A.F., "Physical Desulfuri-
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RI 8118
Chemical Construction Corporation, "The High Sulfur Combustor—Volume I",
National Technical Information Service, Springfield, Virginia,
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617
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Coal Age, "The Coming Surge in Coal Preparation", January 1976
Coal Age, "Multi-Stream Coal Cleaning System Promises Help With
Sulfur Problem", January 1976
Colorado School of Mines, "Removal of Sulfur from Coal by Treatment
with Hydrogen—Phase i", Research and Development Report #77, Interim
Report No. 1
Cuffe, Stanley T., et al., "Emissions from Coal-Fired Power Plants",
National Technical Information Service, Springfield, Virginia, 1967
Cutler, Stanley, "Emissions from Coal-Fired Power Plants", U.S.
Department of Health, Education and Welfare, 1976
Dancy, T.E., "Control of Coke Oven Emissions", AISI Yearbook, p. 181,
1970
Day, James M., "Current Status of Proposed Federal Waste Disposal Rules",
Mining Congress Journal, June 1974
Dell, C.C.; Jenkins, B.W., "The Leeds Flotation Column", United Kingdom,
Australian Coal Conference
Deurbrouck, A.W.; Jacobsen, P.S., "Coal Cleaning — State-of-the-Art",
Coal Utilization Symposium - SO Emission Control, Coal and the
Environment Technical Conference, National Coal Conference,
October 1974
Deurbrouck, A.W., "Sulfur Reduction Potential of the Coals in the USA",
U.S. Bureau of Mines Report of Investigations #7633, 1972
Deurbrouck, A.W., "Survey of Sulfur Reduction in Appalachian Region
Coals by Stage Crushing", U.S. Bureau of Mines Report of Investi-
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Doyle, Frank J.; Bhatt, H.G.; Rapp, J.R., "Analysis of Pollution
Control Costs", Report prepared for Appalachian Regional Commission
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February 1974
Doyle, F.J.; Blatt, H.G.; Rapp, J.R., "Analysis of Pollution Control
Costs", EPA 670/2-74-009
618
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Ellison, William; Heden, Stanley D.; Kominek, Edward G., "System
Reliability and Environmental Impact of SO Processes", Coal Utili-
zation Symposium-Focus on SO Emission Control, Louisville, Kentucky,
October 1974
Engdall, R.B., "A Critical Review of Regulations for the Control of
Sulfur Oxide Emissions", Battelle Columbus Laboratories, APCA
Journal Vol. 23,,#5, May 1973
Environmental Analysis, Inc., "Air Quality in Nassau-Suffolk County,
N.Y.", 1972
Environmental Protection Agency, "Air Pollution Emission Factors",
EPA Publication AP-42, April 1973
Environmental Protection Agency, "Air Pollution Technical Publications
of the Environmental Protection Agency, Research Triangle Park, North
Carolina, July 1974
Environmental Protection Agency, "Environmental Impact Assessment
Guidelines for Selected New Source Industries"
Falkenberry, Harold L., "Emission Controls—Status at Coal Burning
Power Plants", Mining Congress Journal, May 1973
Federal Register, "Standards of Performance for New Stationary
Sources (Coal Preparation Plants)", Volume 39, #207, Part II,
EPA, October 24, 1974
Gayle, J.B.; Eddy, W.H., "Effects of Selected Operating Variables on
Continuous-Cell Flotation of Coal: A Lab Study", U.S. Bureau of
Mines Report of Investigations #5989
Gayle, J.G.; Smelley, A.G., "Selectivities of Laboratory Flotation and
Float-Sink Separations of Coal", U.S. Bureau of Mines Report of
Investigations # 5691, 1960
Geer, M.R.; Jacabsen, P.S.; Sokasi, M., "Dewatering Coal Flotation
Tailing by the Admixture of Crushed Washery Refuse", U.S. Bureau of
Mines Report of Investigations #7110
Goodrich, John C., "Computer Mapping of Coal Reserves by Sulfur Level",
Harvard University, Cambridge, Massachusetts, April 1971
Graham, H.G.; Schmidt, L.D., "Methods of Producing Ultra-Clean Coal
for Electrode Carbon in Germany", U.S. Bureau of Mines IC-7481,
October 1948
619
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Hall, A.W.; Martin, J.W.; Stewart, R.F.; Poston, A.M., "Precision
Tests of Neutron Sulfur Meter in Coal Preparation Plants", U.S.
Bureau of Mines Report of Investigations #8038, 1975
Hand, John W., "Drying of Western Coal", Mining Congress Journal,
May 1976
Helfinstine, R.J., et al., "Sulfur Reduction of Illinois Coals—
Washability Studies, Phase II", Illinois State Geological Survey,
July 1971
Henderson, G.S.; Andren, A.W.; Harris, W.F.; Reichle, D.E.; Shugart,
H.H.; Van Hook, R.I., "Environmental Assessment of SO and Trace
Element Emissions from Coal Utilization", Coal Utilization Symposium-
Focus on SO Emission Control, Louisville, Kentucky, October 1974
Henderson, James, "Environmental Overkill the Natural Resource Impact",
American Mining Congress Convention, October 1974
Hill, George R., "Clean Fuels from Coal—The OCR Challenge", Mining
Congress Journal, February 1973
Hoffman, L.; Truett, J.B.; Aresco, S.J., "An Interpretative Compilation
of EPA Studies Related to Coal Quality & Cleanability", Mitre
Corporation, May 1974, EPA 650/2-74-030
Hoffman, L. et al., "Survey of Coal Availability by Sulfur Content",
Mitre Corporation, May 1972
Hollinden, Gerald A.; Elder, Henry W., "Worldwide Review of Major
Sulfur Dioxide Removal Processes Applicable to Coal-Fired Utility
Boilers", Coal Utilization Symposium-Focus on SO Emission Control,
Louisville, Kentucky, October 1974
Hulett, L.D.; Carter, J.A.; Cook, K.D.; Emery, J.F.; Klein, D.H.;
Lyon, W.S.; Nyssen, G.A.; Fulkerson, W.; Bolton, N.E., "Trace
Element Measurements at the Coal-Fired Allen Steam Plant—Particle
Characterization", Coal Utilization Symposium-Focus on SO Emission
Control, Louisville, Kentucky 1974
looss, R.; Labry, J., "Treatment of Ultra-Fine Material in Raw Coal
In the Provence Coalfield", France, Australian Coal Conference
Irminger, P.F.; Giberti, R.A., "Desulfurization Technology to Meet
the Power Demand", NCA/BCR Coal Conference and Expo II, October 1975
620
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Jimeson, R.M.; Spindt, R.S., "Pollution Control and .Energy Needs",
Advances in Chemistry Series, American Chemical Society, Washington,
D.C., 1973
Jonakin, J., "Solving the SO Problem—Where We Stand with Application
and Costs", Coal Age, May 1975
Journal of the Air Pollution Control Association, "Panel Calls Bene-
ficiation-FGD Combination 'Most Economical, Best All-Around Choice1",
November, 1975
Kennecott Copper Corporation, "Chemical Desulfurization of Coal",
American Mining Congress Coal Convention, May 508, 1974
Kent, James A. (Editor), "Riegel's Handbook of Industrial Chemistry
(7th Ed.)", Van Nostrand Reinhild Publishing Company, New York, 1974
Kester, W.M., "Magnetic Demineralization of Pulverized Coal"
Kilgroe, James D., "Physical and Chemical Coal Cleaning for Pollution
Control", Industrial Environmental Research Laboratory, Environmental
Protection Agency, Research Triangle Park, North Carolina
LaMantia, Charles R.; Raben, Irwin A., "Some Alternatives for SO2
Control", Coal Utilization Symposium-Focus on SO Emission Control,
Louisville, Kentucky, October 1974
Lawrence, William F.; Cockrell, Charles F.; Muter, Richard, "Power
Plant Emissions Control", Mining Congress Journal, April 1972
Leavitt, Jack M., Leckenby, Henry F.; Blackwell, John P.; Montgomery,
Thomas L., "Cost Analysis for Development and Implementation of a
Meteorologically Scheduled SO Emission Limitation Program for Use
by Power Plants in Meeting Ambient Air Quality SO Standards",
TVA Air Quality Branch, Marcel Dekker, Inc., 1974
Leonard, Joseph; Mitchell, David, "Coal Preparation", American Institute
of Mining, Metallurgical and Petroleum Engineers, Inc., 1968
Lewis, Clifford J., "Development of a Rotating Stack Gas Scrubber",
NCA/BCR Coal Conference and Expo II, October 1975
Lowman, Stephen G., "Westmoreland Coal's Bullitt Plant Upgrades Steam
Coal Quality", Coal Age, 1973
621
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Lowry, H.H. (Editor), "Chemistry of Coal Utilization", John Wiley &
Sons, Inc., New York, New York, 1963
Lovell, Harold L., "Sulfur Reduction Technologies in Coals by Mechani-
cal Beneficiation (3d Draft)", Commerce Technical Advisory Board
Panel on SO Control Technologies, March 1975
Luckie, Peter T.; Draeger, Ernie A., "The Very Special Considerations
Involved in Thermal Drying of Western Region Coals", Coal Age,
January 1976
Magee, E.M. et al., "Evaluation of Pollution Control in Fossil Fuel
Conversion Processes; Gasification; Section 1: Koppers-Totzek
Process", EPA Project 69-02-0629
Magee; Hall; Varga, "Potential Pollutants in Fossil Fuels", Environ-
mental Protection Technology Series, ESSO Research & Engineering
Company, June 1973
Markley, R.W.; Cavallaro, J.A., "Efficiency in Cleaning Fine Coal by
Froth Flotation—A Cell by Cell Pilot Plant Evaluation", Mining
Congress Journal, June 1974
Martinka, Paul D.; Blair, A. Ross, "Western Coal Transportation - A
Challenge", American Mining Congress Convention, October 1974
Massey, Lester G., "Coal Gasification", Advances in Chemistry Series,
American Chemical Society, Washington, D.C. 1974
McNally-Pittsburg Manufacturing Corporation, "Coal Cleaning Plant
Prototype Plant Design Drawings", Department of Health, Education and
Welfare Contract 22-68-59
Mesko, J., "Atmospheric Fluidized Bed Steam Generators for Electric
Power Generation", 36th Annual Meeting of American Power Conference,
1974 . •
Meyers, Sheldon, "The Development of Coal Resources and the Environ-
mental Impact Statement", Coal Utilization Symposium-Focus on SO
Emission Control, Louisville, Kentucky, October 1974
Miller, Kenneth J., "Coal-Pyrite Flotation: A Modified Technique
Using Concentrated Second-Stage Pulp", U.S. Bureau of Mines Coal
Preparation Program, Technical Progress Report 91, May 1975
Miller, K.J.; Baker, A.F., "Electrophoretic - Specific Gravity
Separation of Pyrite from Coal", U.S. Bureau of Mines Report of
Investigations #7440
622
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Miller, K.J.; Baker, A.F., "Flotation of Pyrite from Coal", U.S.
Bureau of Mine Technical Progress Report #51, February 1972
Miller, R.E.; Agarwal, J.G.; Petrovic, L.J., "Economic & Technical
Considerations in the Use of Coal as Clean Fuel", American Mining
Congress Convention, May 6-9, 1973
Mining Congress Journal, "Pilot Plant for Solvent Refining of Coal"
January 1973
Montgomery, T.L.; Frey, J.W., "Tall Stacks and Intermittent Control
of SO Emissions TVA Experience and Plans", American Mining Congress
Convention, October 1974
Nandi, S.P.; Walker, P. L., Jr., "Absorption Characteristics of Coals
and Chars", National Technical Information Service, Springfield,
Virginia, April 1972
National Coal Association, "Coal Makes the Difference", 56th National
Coal Association Convention, June 1973
National Coal Association, "Coal Utilization Symposium—Focus on SO
Emission Control", Coal and the Environment Technical Conference,
October 1974
National Coal Association, "Second Symposium on Coal Utilization",
NCA/BCR Coal Conference and Expo II, October 1975
Norton, Gerry; Bluck, Willard V., "A High Intensity Fine Coal Flotation
Cell", American Mining Congress Coal Convention, Pittsburgh,
Pennsylvania, May 1975
Norton, Gerry; Symonds, D.F.; Zimmerman, R.E., "Yield Optimization
in Process Plan Economics", AIME Annual Meeting, New York, New York,
February 1975
O'Brien, Brice, "Environmental Protection", Mining Congress Journal,
February 1974
O'Hara, J.B.; Ripper, S.N.; Loran, B.I.; Mindheim, W.I., "Environmental
Factors in Coal Liquification Plant Design", EPA Symposium on
Environmental Aspects of Fuel Conversion Technology, May 1974
Ottmers, Delbert M.; Phillipps, James L.; Sipes, Teresa G., "Factors
Affecting the Application of Flue Gas Desulfurization Systems to
Gas- and Oil-Fired Power Plants Being Converted to Coal-Fired Units",
NCA/BCR Coal Conference and Expo II, October 1975
623
-------
REFERENCES AND/OR ADDITIONAL READING
(Continued)
Padgett, Joseph, "Sulfates—Recent Findings and Policy Implications",
NCA/BCR Coal Conference and EXPO II, October 1975
Paul Weir Company, Inc., "An Economic Feasibility Study of Coal
Desulfurization", Chicago, Illinois, October 1965
Phelps, E.R., "Federal Coal Leasing Policy", American Mining Congress
Convention, October 1974
Poland, "Beneficiation of Coal Fines by Selective Flocculation",
Australian Coal Conference
Quig, Robert H., "Chemico Experience for SO Emission Control on Coal-
Fired Boilers", Coal Utilization Symposium—Focus on SO Emission
Control, Louisville, Kentucky, October 1974
Resource Planning Associates, Inc., "Energy Supply/Demand Alternatives
for the Appalachian Region—Executive Summary", Council for Environ-
mental Quality, Appalachian Regional Commission and the National
Science Foundation, Report EQ-022, March 1975
Roberts & Schaefer Company, "Design & Cost Analysis Study for Proto-
type Coal Cleaning Plant", August 1969
Rubin, E.S.; MacMichael, F.C., "Impact of Regulations on Coal Conversion
Plants", Environmental Science & Technology, 9, 112, 1975
Sage, W.L., "Combustion Tests on a Specially Processed Low-Ash, Low-
Sulfur Coal", National Technical Information Service, Springfield,
Virginia, 1964
Sableski, Joseph J., Jr.; Sedman, Charles B.; Jones, Larry G.,
"Development of Standards of Performance for New Coal Preparation
Plants", Mining Congress Journal, October, 1972
Saleem, A., "Commercial SO Removal at Detroit Edison Using Limestone
in a High Velocity Spray Tower", Coal Utilization Symposium-Focus on
SO Emission Control, Lousville, Kentucky, October 1974
Schaeffer, Stratton C.; Jones, John W., "Coal Preparation vs. Stack Gas
Scrubbing to Meet SO Emission Regulations", NCA/BCR Coal Conference
and Expo II, October 1975
Soderberg, H.E., "Environmental Energy & Economic Considerations in
Particulate Control", American Mining Congress Coal Convention,
May 5-8, 1974
624
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Stacy, W.O.; Walker, P.L., Jr., "Structure and Properties of Various
Coal Chars", Pennsylvania State University, National Technical
Information Service, Springfield, Virginia, September 1972
Stoev, St.; Krasteva, K., "Coal Preparation by Reverse Stratification",
Bulgaria, Australian Coal Conference
Tompos, E., "Detailed Investigation of Pyrites Distribution, Taking
Account of the Petrographic Components of Coal, with a View to
Reducing the Pyrites Content in Coking Coal", Hungary, Australian
Coal Conference
Tyler, C.E., "Testing Sieves & Their Uses", Combustion Engineering, Inc.
Handbook #53, 1973 Edition
U.S. Bureau of Mines, "Clean Energy from Coal Technology", Overview of
Coal/Energy Usage, U.S. Government Printing Office, 1974
U.S. Bureau of Mines, "Coal—Bituminous and Lignite in 1973", Division
of Fossil Fuels, U.S. Department of Interior Mineral Industry
Surveys, January 1975
U.S. Bureau of Mines, "Commodity Data Summaries - 1976"
U.S. Bureau of Mines, "Methods of Analyzing and Testing Coal and Coke",
Bulletin 638, Office of the Director of Coal Research, 1967
Vasan, Srini; Willett, Howard P., "Alternate Desulfurization Techniques
For Coal Gasification Projects", NCA/BCR Coal Conference and Expo II,
October 1975
Volsicky, Z.; Puncmanova, J.; Hosek, V.; Spacek, F., "Bacteriological
Leaching-Out of Finely Intergrown Sulfur in Coal: Method and
Features", Czechoslovakia, Australian Coal Conference
Warnke, W.E., "Latest Progress in Sulfur, Moisture and Ash Reduction
Coal Preparation Technology", American Mining Congress Coal
Convention, Detroit,. Michigan, May 1976
West Virginia Geological & Economic Survey, "Suitability of West
Virginia Coals to Coal Conversion Processes", Coal-Geology Bulletin
No. 1, December 1973
Yenovsky, A.Z.; Remesnilsov, I.D., "Thermomagnetic Method of Concen-
trating and Desulfurizing Coal"
625
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REFERENCES AND/OR ADDITIONAL READING
(Continued)
Zitting, Richard T., "Solid Fuels: Their Contribution to Energy
Independence", American Mining Congress Convention, October 1974
626
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APPENDICES
627
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APPENDIX I
Glossary of Selected Terms
628
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APPENDIX 1
GLOSSARY OF SELECTED TERMS
Abatement
Abrasiveness
Abutment
Acid Producing
Materials (Acid
Forming)
Acid Mine
Drainage
Acid Soil
Acid Spoil
Acre-Foot
A statement of the reduction of pollution effects of
mine drainage.
Abrasiveness is the ability of coal to cause wear
and is significant because it increases costs.
The ash content of a coal causes most of the wear.
The point of contact between the ends of an
embankment and the natural ground material is
called the abutment.
Usually, rock strata containing significant pyrite
which if exposed by coal mining will, when acted
upon by air and water, cause acids to form.
Any acid water draining or flowing on or having
drained or flowed off, any area of land effected
by mining is called acid mine drainage (AMD).
Generally, a soil that is acid throughout most or
all of the parts of it that plant roots occupy is
referred to as acid soil, commonly applied to only
the surface-plowed layer or some other specific
layer or horizon of the soil. Practically, this
means a soil with a pH less than 6.6; precisely,
a soil with a pH less than 7.0. Alternately, a
soil having a preponderance of hydrogen or hydroxyl
ions in the soil solution may be referred to as acid.
The spoil or waste material containing sufficient
pyrites so that the weathering produces acid water
and where the pH of the soil determined by standard
methods of soil analysis is between 4.0 and 6.9.
A term used in measuring the volume of water, equal
to the quantity of water required to cover 1 acre
x 1 foot in depth, or 43,560 cubic feet.
629
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Aquifer
Ash Balance
A water bearing formation through which water moves
more readily than it can through an adjacent
formation with lower permeability.
Ash balance is a method for estimating the amount
of one of the products or the feed to a unit process
or an entire operation by means of known ash
percentages for each. The process is analogous to
conservation of matter and may be thought of as
"conservation of ash."
Ash Constituents - The principal contributors to coal ash are the
following mineral groups: the shale group, the
kaolin group, the sulfide group and the carbonate
group. Most ash constituents are present as
silicates. The most abundant oxides present in
coal ash are silica (SiO ), aluminum oxide(Al 0 ),
ferric oxide (Fe 0 ) and calcium oxide (CaO).
Ash Content
Ash Error
Ash Fusion
Temperature
Ash content of a coal is inorganic residue remaining
after ignition of combustible substances, and is
determined in the proximate analysis of a coal
sample. After the moisture of the sample is
established, the weight of ash is found by placing
the sample in a cool electric muffle furnace and
gradually increasing the temperature to 700 to
750 C and holding this temperature for 10 to 15
minutes until all the carbon has burned off. Then
the ash is weighed and ash percentage (%A) is
determined according to the following:
%A = weight of ash
weight of sample
Ash error indicates the difference between the ash
content of the clean coal product and the theoreti-
cal ash from the washability data at the same yield.
Ash fusion temperature is the temperature at which
the ash of a coal softens or fuses. If the ash
fuses at a comparatively low temperature, it may
cause clinkering or slagging when the coal is
burned. The ash fusion temperature is found by
heating a cone made from ash of the given coal, in
a furnace where the temperature can be gradually
increased. The ash softening temperature is that
temperature at which the ash becomes a spherule,
and is read using an optical pyrometer, or with a
suitably place thermocouple.
630
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Ashline
Blinding
Breaker
Btu
Btu Value
Bulk Density
A relationship between specific gravity and percent
ash of a coal. This information, which is used to
accomplish curve fitting, is at the present time
largely determined by experience. It supplements
actual test data or specified data to aid in
determining smaller increments, for use in calcula-
tions, by interpolating or extrapolating from the
given points.
Blinding is a term describing the lodging of pieces
of coal or slate in the bed of material being
carried on a screen deck which results in a decrease
in open area for the particles to pass through the
screen surface.
A breaker is often called a "rotary breaker." It
is a rotating drum type coal crushing machine with
internal lifting vanes, and with holes in the drum
shell which pass the largest size of coal desired.
The coal is broken by impact inside the drum in
dropping from the lifting vanes. An important
feature of the breaker is that undesirable ash
producing rock and shale is often tougher than coal
and discharges with other unbreakables. The
unbreakables, timbers, tramp iron, etc., are dis-
charged from the end of the drum away from the
feed and this helps to reduce the refuse load and
nuisance load in the remainder of the preparation
process. The breaker is commonly the first process
piece of equipment in the preparation plant.
One Btu is defined as the amount of heat required
to raise the temperature of one pound of water one
degree Fahrenheit.
Btu value, also known as the calorific value or
heating value, is usually expressed for a solid
fuel as Btu per pound of fuel. This Btu may be
based on an "as received," a "dry," or a "moisture
and ash-free" basis and the basis should always be
stated. It is the heat of combustion of a substance
as determined by test using an oxygen bomb
calorimeter.
Bulk density is the weight per unit volume of
aggregates of materials. The usual units of bulk
density are pounds per cubic foot (PCF). This
includes the weight of the moisture in the aggregate.
The solid material must necessarily be in pieces
and air fills the voids in the aggregate volume.
631
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Classification
Classifier or
Classifying
Cyclone
The bulk density is significant — though generally
of a somewhat different value — with material in a
container or free standing, or with the material
suspended in a stream of air, or with material in
motion. In motion the materials again can show
different bulk densities when in free fall, traveling
down chutes, or with different methods of conveying.
Reducing the moisture content of coal, for example,
can sometimes increase the bulk density and coarser
coal often has a higher bulk density than finer coal.
A common bulk density used for coal is 50 PCF
whereas the solid density of the coal might be about
90 PCF. The solid density of coal is usually des-
cribed as "specific gravity" to help eliminate
confusion in the type of density being considered.
Classification is a "sizing" process where the
effects of specific gravity of the particles is
a factor in the separation. When a sizing is
carried out on screens the particle must pass
through a given hole size and thus particle
dimensions are of primary importance. Classifi-
cation, in contrast, is usually a solid-particle-
in-a-fluid sizing process where heavy fine particles
can join lighter coarse particles. In the
classification process, if the particles are all
of the same specific gravity, a pure size separation
is possible. Also some classification devices can
be designed or adjusted to minimize specific gravity
phenomenon to give a result closer to pure size
separation. Particle shape is also a factor in
both screen sizing and classification of particles
in fluids. Generally particle shape is of somewhat
secondary importance and shows up in other measured
variables.
A classifier cyclone is used as a hydraulic centri-
fuge or thickening slurry solids. The overflow is
controlled by an overflow valve, and the size of
both overflow and underflow orifices. Normally
the underflow volume is about 10 percent of the
feed volume. By closing down the overflow valve a
back pressure is applied, forcing more flow out
the underflow. This lowers the classification
point, which is the particle size of a material
that is distributed equally between the overflow
and the underflow. Thus, the classification point
is adjusted to cause separation to occur at
different sizes.
632
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Coefficient of
Permeability
Comminution
The rate of flow of a fluid through a unit cross
section of a porous mass under a unit hydraulic
gradient at a standard temperature is called the
coefficient of permeability. The standard coeffi-
cient of permeability used in the hydrologic
work of the United States Geological Survey is
defined as the rate of flow of water at 60 F in
gallons or millions of gallons a day, through a
cross section of 1 sq. ft. under a hydraulic
gradient of 100%.
Comminution is reduction to a smaller size,
accomplished either on dry coal or in aqueous pulp.
Depending on the size of the material being
comminuted, the operation is regarded as crushing
or grinding. In general, coarser materials are
crushed.
Compressive
Strength
Compressive strength is defined as resistance of
material to rupture under compression, expressed as
force per unit area. The load-bearing ability of
coal, especially in pillars, as well as its strength
in crushing and grinding, are reflected by the
various measures of Compressive strength. There is
a general relationship between the rank of a coal
and its compressive strength. However, there is
no single standard way to measure compressive
strength because coal is not a homogeneous material.
It contains random cracks, and a small sample taken
from the coal-mine face into the laboratory does
not necessarily reflect bed conditions of loading
and strain.
Concentration
Concentrating
Table
Concentration is the term applied to the amount of
any substance occurring in a given amount of water-
the common unit is parts per million (PPM) or
miligrams per liter (mg/1).
The concentrating table employs the principle of
flowing a mixture of coal and water over a series
of riffles on a slightly tipped table which is
oscillated rapidly to effect a separation of the
coal by particle size and specific gravity.
Essentially the table consists of a pair of steel
frames upon which are mounted two rubber-covered
decks and a drive mechanism. Each flat, rhomboid-
shaped deck is approximately 17 feet long on the
clean coal discharge side and 8 feet wide on the
refuse discharge side. It is supported in an
essentially horizontal plane, but is slightly
633
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Cyclone, Wet
Classifying
Deep Cleaning
Degradation
Density
declined so that water fed along the upper side
will flow across the table surface and discharge
along the lower clean coal side. The deck is
attached to a differential-motion drive which gives
it a quick-return conveying motion, moving material
lying on the table surface away from the drive end.
The drive motion is perpendicular to the short
sides of the rhomboid. Attached to the rubber
covering on the deck is a system of parallel rubber
riffles which taper toward the refuse end of the
table and run in the direction of the conveying
motion. At one corner of the long diagonal and
above the deck is a feedbox with a slotted bottom
to spread the feed onto the deck. Beside the
feedbox and by the upper, longer side of the deck
is a trough having adjustable gates through which
the flow of dressing water to the deck is.
distributed.
The cyclone makes use of the mechanical properties
of a vortex to effect the separation of coal. A
raw coal slurry enters a cylindrical chamber
tangentially with a given velocity and spirals
downward onto a conical section, forming a strong
vortical flow. The larger and heavier particles
move along the wall of the conical chamber and are
discharged through the underflow opening known as
the apex orifice. The lighter and smaller particles
have less tendency to settle at the wall and are
forced to the core of the vortical flow. A tube
called the vortex finder is positioned coaxially
in the cyclone and collects the particles that are
forced to the core. This material is termed
overflow.
Deep cleaning is the cleaning of coal to maximize
reduction of impurities, especially sulfur, within
economic limitations and generally implied is that
the specific gravity of separation is lower than in
normal plant operation. This is done by crushing
to finer sizes and cleaning with conventional equip-
ment, placing emphasis on maximizing the sharpness
of separation.
Degradation is the term applied to the breakage of
coal caused by weathering or handling.
A synonym for specific gravity, which might be solid
denisty, liquid denisty or an overall density of
a composite of solids and liquids.
634
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Density Control
Desliming
Dewatering
Distribution
Distribution
Curve
Distribution
Factor
Distribution
Number
The specific gravity of the circulating medium of
a heavy media cyclone is monitored by a density
control sensing device. Any deviation from the
desired specific gravity causes an error signal to
be sent to a control motor, causing an appropriate
change in the feed rate of thickened medium to the
medium sump. The amount of magnetite in this flow
of thickened medium, then, compensates for the
amount of water retained on the drained products.
The automatic control system maintains suitable
balances and, therefore, preserves the desired
specific gravity of the medium.
Desliming is the washing of micronsized particles
from a product by passing it over a screen and
subjecting it to water sprays.
Dewatering of coal is the removal of excess surface
moisture.
Distribution refers to the percentages of each
density fraction of the raw coal which reports to
the clean coal. Distribution has a different
value, as a rule, for each density fraction and
for each size range of the given density fraction.
This is sometimes called the partition curve. The
distribution curve indicates for each specific
gravity fraction, the percentage of the specific
fraction which is contained in one of the products
of the separation (e.g., the clean coal). The
curve values are plotted against the mean density
of the particular fraction. It is used as a
measuring and design criterion for cleaning methods
and equipment. A distribution curve may also be
plotted for a size fraction in reference to a piece
of sizing equipment though its main use is with
separations which are a function of specific
gravity.
This is sometimes called the partition factor. It
is the percentage of a specific gravity (or size)
fraction recovered in one of the products of the
separation (e.g., the clean coal). It is a more
general term than distribution number.
The distribution number is an absolute value that
gives the percentage of the raw coal specific
gravity fraction which reports to the reject of a
piece of cleaning equipment. Engineers in the
635
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Distribution
Value
Draining
Electrostatic
Properties
(Electrostatics)
Error Area
Ferric Iron
United States use distribution number for the
percentage of the raw coal specific gravity
fraction that reports to the clean coal.
This can be a synonym for distribution number. See
distribution number definition. Distribution value
can refer to other numbers also, such as probable
error, specific gravity of separation, imperfection
and error area.
Draining is the removal of water and media from a
product of a heavy medium sink and float separator
by passing the product over a vibrating screen with
openings too small to permit loss of product, but
which will pass the media.
Electrostatics is the science of electric charges
captured by bodies which then acquire special
characteristics due to their retention of such
charges. Dry coal particles acquire charges as they
pass through a high-voltage field. They are then
deflected from their natural falling path in accord-
ance with the attraction or repulsion due to the
influence of their retained charge as they pass
other charged bodies.
Error area is the area between the actual distribu-
tion curve obtained in practice, and a theoretically
perfect distribution curve which indicates 100
percent of the raw coal lighter than the separating
gravity going to washed coal and zero percent of
the raw coal heavier than the separating graving
going to washed coal. It is a measure of the total
misplaced material to clean coal and refuse, and
is a "sharpness of separation" criterion.
Ferric iron is an oxidized or high-valence form of
iron (Fe ) responsible for the red, yellow, and
brown colors in soils and water.
Ferrous Iron
Float-and-Sink
Testing
Ferrous i$on is a reduced or low-valence form of
iron (Fe ) imparting a blue-gray appearance to
water and some wet subsoils on long standing.
Float-and-sink testing is known more scientifically
as specific-gravity analysis, and is based on the
difference in specific gravity between coal and its
associated impurities. The concept involved is
simply to procure a valid sample and effect a series
of separations on the basis of specific gravity
differences. This is done by immersing the sample
636
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Float-and-Sink
Testing
(continued)
Flotation,
Froth
Flotation Cell,
Froth
in a series of heavy liquids, starting at about 1.30
specific gravity, and incrementing up to about 2.00
specific gravity. The float material is drawn off
the first heavy liquid and set aside for drying and
weighing and the sink material is placed in the next
higher gravity liquid for a similar separating
process. When the float material products from
each gravity fraction are separated and set aside
and a final sink product is also set aside and
dried, the products are weighed. These weights are
converted into percentages of the total sample and
reported. Then, the specific gravity fraction
samples are analyzed for ash, sulfur, and any other
chemical characteristics desired. The data obtained
in the analysis of a raw coal is useful in predicting
the amenability of that particular coal to upgrading
by washing. If the clean coal and refuse of a wash-
ing operation are also subjected to specific gravity
analysis, the data obtained is used to determine the
distribution curve and associated sharpness-of-
separation criteria.
A mechanical/chemical process which is based on the
selective adhesion of some solids in suspension to
air bubles while other solids in the suspension
selectively adhere to water. A separation occurs
when finely disseminated air bubbles are passed
through a feed-coal slurry. The clean coal adheres
to the bubbles while other solids in the suspension
the surface where the forming froth is skimmed off
and dewatered. The refuse tends to stay in suspen-
sion. Reagents are used to enhance selectivity by
establishing a hydrophobic or air-loving surface on
certain solids (i.e., clean coal particles) while
the other solids (i.e., refuse) are rendered
hydrophilic or water-loving.
Flotation cells are of two basic types, pneumatic
cells and mechanical cells. The prototype plant
will be using a mechanical type of call known as
a Fagergren cell. This Fagergren cell features a
rotor-stator assembly for agitation and aeration of
the pulp. The stator consists of cylindrical
spacers mounted between two rings which are rigidly
fastened to the tank. The rotor construction is
similar to that of the stator, except that the upper
and lower bladed impellers are mounted within the
rings. The rotor is suspended on a short drive
shaft and rotates within the stator. Pulp enters
directly into the tank through a suitable opening.
637
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Flotation Cell,
Froth
(continued)
Friability
Free Swelling
Index (F.S.I.)
The pulp is drawn by the impeller blades into the
rotor. Rapid pulp displacement creates a partial
vacuum which causes air to enter into the rotor
through the standpipe. The air is dispersed through
the pulp in the form of fine bubbles. In passing
between the cylindrical spaces of the rotor and
stator, the pulp-water-air-mixture is highly agi-
tated, giving efficient aeration. The froth is
removed by a rotating skimmer and the refuse is
drawn off at the bottom of the tank.
The complement of size stability, friability is the
tendency toward breakage on handling. It is an
indication of the strength of the coal, and also
an indication of preparation cost per ton since
this is a function of the number of particles per
ton of feed. The greater the proportion of fines
in the feed, the greater the expected total prepara-
tion cost.
"Free Swelling Index" value is also known as the
"coke button" value. It is determined using a
simple test described in ASTM D720-67, "Free
Swelling Index of Coal." The value obtained gives
an approximate measure of the caking and coking
characteristics of coal, but not of coal expansion
properties in coke ovens. It is intended to
describe the caking characteristics of a coal, or
the opposite characteristic, free-burning. A one
gram sample of minus 60 mesh coal is heated under
prescribed conditions in a crucible and the
resulting "button" is compared to a series of 17
button shapes ranging on a scale of values from 1
to 9, by halves. A match is made with one of the
buttons on the scale and the number of that button
is the F.S.I, value.
Grizzly
Hardgrove Grind-
ability Index
A grizzly is a screen surface composed of parallel
bars. The bars are usually tapered toward the
discharge end to prevent clogging. Grizzlies are
intended for coarse scalping and may be either
fixed, movable or vibrating.
Hardgrove Grindability Index (HGI) is used to
determine a relative measure of the hardness of a
coal. A special ring-and-ball-type grindability
mill, as specified in ASTM D409-71 (see Appendix 8)
is used to grind a 50 gram sample of 16 by 30 mesh
coal for 60 revolutions. The sample is then sized
at 200 mesh by 10 minutes of mechanical sieving.
638
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Hardgrove
Grindability
Index
(continued)
Hardness
Heavy Media
(H.M.) Cyclone
Hydrocyclone
Imperfection
Factor
The HGI number can be approximated using the
equation HGI = 13+ 6.93 W, where W = (50 gm. -X),
X being the weight of the material retained on the
200 M sieve. The 1971 revision of the method makes
the exact index number a function on graphs deter-
mined from testing coals of known value on the given
testing machine and accessories. (See "Rosin-Rammler
plot" for relationship between HGI numbers and the
slope of the screen analysis plot.) Higher index
numbers represent softer, more breakable coal. The
HGI number is lower for harder, less breakable coal.
• Defined by Hardgrove Grindability Index, hardness is
a measure of the ease with which a coal may be made
into a pulverized fuel. Thus, it is an indirect
measure of the energy required to reduce a coal in
size.
A heavy media cyclone employs centrifugal force on
a coal in a heavy medium suspension, having a higher
specific gravity than water, to effect a sharper
separation between coal and impurity than can be
obtained in other types of cleaners handling the
same size range of coal. A suspension medium, of
fine magnetite particles in water, carrying raw
coal particles is fed to the heavy media cyclone.
The clean coal reports to the overflow and the
refuse material reports to the underflow. Separating
concentration effects are maximized by use of a
smaller cone angle than that of a hydrocyclone, 20
being about standard in the case of the heavy media
cyclone.
The Hydrocyclone is a cyclone that does not employ
an artificially higher specific gravity suspension
but uses water only as medium for the coal. How-
ever, coal fines are generally accepted as
contributing to a higher effective separating gravity.
Design of the hydrocyclone differs from that of the
conventional heavy medium cyclone by providing a much
greater cone angle — up to 120 — and a longer
vortex finder. Hydrocyclones are operated to
suppress size classification phenomena in favor of
specific gravity type concentration effects.
The imperfection factor is equal to the probable
error divided by a quantity equal to the specific
gravity of separation minus the specific gravity of
the separting medium. For jigs, tables, rheolaveurs
and other washers the gravity of the separating
medium, which is subtracted from the specific gravity
of separation, is taken to be 1.
639
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Independent
Criteria
(Coal washing)
Inherent
Moisture
The independent criteria are the performance criteria
which are characteristic of the washing unit and
which are substantially unaffected by the specific
gravity composition of the raw coal are probable
error, area error, and imperfection factor. They
are commonly referred to as the sharpness-of-
separation criteria.
Bed moisture, as opposed to extraneous moisture,
is termed inherent. The moisture content retained
by the coal when in equilibrium with an atmosphere
over a saturated solution of potassium sulfate at
30 C. is known as the equilibrium moisture of the
coal. This atmosphere has a 96 to 97 percent
relative humidity. When extraneous or free
moisture is present in the coal, inherent moisture
and equilibrium moisture may be considered to be
the same. The inherent moisture is directly
related to the rank of the coal.
Low Gravity
Cleaning
Magnetic
Properties
The washing of coal at a specific gravity of
separation of approximately 1.40 or lower.
Those characteristics of coal and associated
impurities which cause the particles to be attracted
to, repelled from, or neutral to a magnetic pole
are considered to be magnetic properties. These
properties of coal can be utilized in a separation
process using dry coal passing through a magnetic
field.
Magnetite
Mesh Size
Magnetite is a black isometric mineral (Fe 0.) of
the spinel group that is an oxide of iron and an
important iron ore. Having a specific gravity in
the vicinity of 5, it can be ground to a fine size,
and mixed with water to form a heavy media suspen-
sion to be used, for example, in heavy media
cyclone circuits.
Mesh size or, as it is sometimes called, "screen
mesh size" have several standards. The most common
standard in the coal industry is the "Tyler square-
root-of-two series" and is the standard followed
generally in U. S. research. ASTM specifications
D 410, D 431, E 11 and E 323 which are listed in
Appendix 8 include complementary mesh openings.
ASTM standard E 11 contains the U.S.A. Standard
Series. Where a specific series is called for in
a particular procedure, as with the determination
of the Hardgrove Grindability Index, or with
640
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proximate or ultimate analysis following ASTM
procedures, where the U.S.A. Standard Series is
specified, then such a specified series should be
used.
Some sizes are designated by millimeters; e.g.,
h mm, 1 mm, 1.5 mm. These are ordinarily sizes
which are used in dewatering or desliming. In
these cases, long slotted openings of the stated
opening width are commonly used. This opening
size can be converted to a nominal mesh size, but
it is not actually one, for a mesh size implies a
square opening.
Also, sizes finer than 200 mesh are designated in
microns. Screening below 200 mesh is something of
a hypothetical process. Accurate actual screening
is difficult at best although it is performed,
and screening efficiency is very low for the screens
readily blind. Thus the micron designation applies
more to a mesh size by specifying a theoretical
square opening which the actual particle would
theoretically pass through. Micron size is also
used in fine particle settling size designations.
By suitable definition, the micron size charac-
terization of a given particle should be very close
in both cases.
The following is a size by size designation of the
mesh sizes with the series to which a given mesh
size refers. At 200 mesh (74 microns) both Tyler
and U.S. Standard have the same opening size so
this size is not included in the list.
Tyler Mesh Sizes U.S. Standard Mesh Sizes
14 (1,168 microns) 8 (2,380 microns)
28 (589 microns) 16 (1,190 microns)
48 (295 microns) 30 (590 microns)
100 (147 microns) 60 (250 microns)
The figure in parenthesis in the above listing
(xxx microns) is the opening dimension between
wires of the particular mesh.
Metallurgical - Coal which is suitable for coking and as coke has a
Coal high compressive strength. The coal usually has a
maximum sulfur (about 1%) and a maximum ash content
(about 10%) and naturally or by blending with a
different coal will, in aggregate, behave as a
medium volatile coal. A medium volatile coal is
641
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Metallurgical
Coal
(continued)
Misplaced
Material
Near-Gravity
Material
usually considered to have a volatile matter
percentage in some range including 30 percent
volatile matter.
Total misplaced material is that percentage of the
feed which reports to the wrong product.
The amount of near gravity material is that percen-
tage of material in the feed withing ^0.10 specific
gravity units of the specific gravity of the separa-
tion. See the "Specific Gravity of Separation"
definition below.
Organic Sulfur
Content
- See Sulfur.
Oversize
Performance
Criteria
Petrographic
Constituents
Porosity
The oversize material is the material which stays
on a given screen; i.e., not passing through the
screen openings.
Performance criteria are the criteria that depend
both on the washing characteristics of the coal
being treated and on the sharpness of the separation
achieved by the washer. These are also called
dependent criteria, and include recovery efficiency,
misplaced material, and ash error.
These are the constituents of coal discernible by
miscroscopic examination. These constituents are
important in determining coal rank and in carboniza-
tion studies. Coal petrography is a highly
specialized field and extensive work has been done
in regard to recognizing and naming petrographic
components; and in correlating coal characteristics
with these components.
Porosity is the ratio "p" expressed as a percentage
of the volume "Vp" of the pore space in a mineral to
the total volume "Vr" of the mineral, the latter
volume including mineral material plus pore space
(coal is a mineral).
Prewetting
Screen
A prewetting screen is a screen used in coal
preparation ahead of a heavy medium separator to
wash the fines from the material not removed by
previous screening and to wet the surface of each
particle before it enters the heavy medium bath.
642
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Primary
Dewatering
Screen
Primary Screen
A primary dewatering screen is a screen used in a
coal preparation plant. It receives all the coal
and water from the washer and may or may not be
followed by further dewatering screens.
A primary screen is a screen used in connection
with heavy media processes. Its purpose is to
remove fine sizes from the coal ahead of the
separator. The screening is usually aided by
using water sprays.
Probable•error is obtained directly from the
distribution curve and is numerically equal to
one-half the specific gravity difference between
the 25 and 75 percent washed coal recovery ordinates
on the curve. It is frequently designated by the
symbol "Ep".
Probable Maximum - The most severe flood flow that would be expected
Flood to occur from the most critical hydrometeorological
conditions that would be reasonable possible in a
region. The occurrence of a flood of this magnitude
would be highly improbable.
Probable Error
Proximate
Analysis
Pulp
Pulp Density
Proximate analysis is a type of analysis of coal that
has been in existence for many years. Proximate
analysis is the determination, by prescribed methods,
of moisture, volatile matter, fixed carbon (by
difference) and ash. Details of a frequently used
proximate analysis can be found in U.S. Bureau of
Mines Bulletin 638, pp. 3-7. A similar analysis can
be found as designated by ASTM but not specifically
called "proximate analysis" in ASTM D271-68,
"Laboratory Sampling and Analysis of Coal and Coke"
Sections 6 through 17 under Methods of Analysis for
Moisture, Ash, Volatile Matter and Fixed Carbon
(Fixed Carbon by Difference).
A slurry, but usually a slurry with more than one
type of solid component.
The percentage by weight of solids of a solids-
water mixture.
Pyritic Sulfur
Rank
- See Sulfur.
v ••
- The rank of a coal expresses the degree to which the
original coal-forming material has been changed
by metamorphism through successive states from
peat to anthracite.
643
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Rapped Sieve
Bend
Raw Coal
Recovery
Efficiency
Recurrence
Interval
Refuse
Rescreen
Rinsing
R.CKM. Coal
Rotary Breaker
Scalping
Scrubber Screen
Secondary
Dewatering
Screen
- A rapped sieve bend is a sieve bend equipped with a
rapping device. The rapping causes vibrations in
the apparatus and thus tends to prevent blinding
of the screen, thus allowing normal operation,
(see Sieve Bend).
- Raw coal is run-of-mine coal which has been reduced
to a given top size by screening and crushing, and
has not received other preparation.
- Recovery efficiency is defined as the ratio,
expressed as a percentage, of the yield of washed
coal to the yield of float coal of the same ash
content shown to be present in the feed by the
specific gravity analysis.
- Recurrence interval (return period) is the average
time between actual occurrences of a hydrological
event of a given or greater magnitude.
- Washed or separated waste material from the raw coal
which was the object of the cleaning process. This
material is also called "gob", "slate" or "hutch".
- Rescreen is the term applied to the screen used to
remove the degradation product or undersized
material from a product which has not been removed
by prior screening operations.
- Rinsing is a term used to describe the use of
water sprays over the screen deck to remove clay
or other foreign substances, as employed in
dense medium separation.
- "Run-of-Mine" coal is coal produced by mining
operations before any preparation.
- See Breaker.
- Scalping is removing coarse, oversized material,
usually ahead of a crusher or other primary process
equipment to reduce the load on the specific process
equipment.
- A scrubber screen is a revolving screen with a
scrubbing section of blank plates containing lifters
to agitate the material.
- A secondary dewatering screen follows a primary
dewatering screen and dewaters and classifies the
smaller sizes in a coal preparation plant.
644
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Shaking Screens
Screening
Efficiency
Shape Factor
Shaking screens are long screen bodies hung from
flexible supports and supported by eccentrics.
They have a long stroke at a relatively low speed.
Screening efficiency is a rating percent figure
used in describing a screening unit. The values
used in the formula are determined by laboratory
testing of actual feeds and products. In the
reverse process, a given efficiency is frequently
used in design and with proper selection is capable
of ultimate verification after the installation is
put into service. One measure of screening effi-
ciency is the percent of the undersize in the feed
that actually passes through the screening surface,
or:
% of feed (or amount) which
actually passes through
screen surface
Efficiency of Screen
Undersize Recovery
% of feed (or amount) which
is undersize (should pass
through screen surface)
Another generally recognized formula for screening
efficiency is:
Screen Efficiency
Where:
% of feed (or amount) which
is oversize on screening
surface
% of feed (or amount) which
actually passes over screen-
ing surface
% true oversize in material
passing over screen deck, as
determined by testing sieves,
where 100% represents all of
the screen deck.
Shape factor is that property of a particle which
determines a relation between the particle surface
area and the particle volume. It correlates with
particle response to fluid type friction effects.
The shape factor is equal to "one" for spheres.
It is calculated by dividing the actual surface
area of the particle, by the surface area of a
sphere having the same volume as that of the
particle. Various fluid frictional effects are
involved throughout the many aspects of coal
preparation. More specifically, they are present
in screening and jigging, hindered settling, dust
645
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Shape Factor
(continued)
Sharpness of
Separation
Sieve Bend
Sieve Scale
Size Consist
Sizing
collection, and in general anywhere that a
particle must travel in a fluid or film.
The sharpness of separation for most cleaning
devices diminishes with the increase in specific
gravity of separation. It may be measured by an
imperfection factor, which for jigs, tables and
other equipment using water as a separating
medium, is often taken as equal to the probable
error divided by the specific gravity (from the
distribution curve), minus the specific gravity of
the separating medium. Later studies of the
imperfection factor, as related to dense media
vessels, indicate that a more constant imperfection
factor value may be obtained by dividing the probable
error by the specific gravity of the separation
only. Imperfection factor thus tends to correct
for the increase in probable error and results in
a numerical figure that characterizes a particular
cleaning device regardless of the separating gravity.
A sieve bend is a rigidly spaced and truly fixed
screen used for preliminary sizing and dewatering
of coal ahead of vibrating screens and centrifuges.
It is a stationary, curved, wedge bar screen with
the bars oriented at right angles across the line
of flow.
A sieve scale is a list of apertures of successfully
smaller screens and step sizing operation. The
sieve ratio is the ratio of the aperture of a given
screen and a given sieve scale to the aperture of
the next finer screen.
Size composition or size consist is the specification
of the percentage of coal, based on weight, in each
size range. The size ranges must be stated. Size
composition is a relative indication of the ease
of degradation of a coal, which in turn is a
function of friability, physical strength, and so
on. Size consist is determined by a sieve analysis
and may be expressed as a percentage between two
sieve sizes or by accumulative percentages.
Sizing is the process of dividing a mixture of
grains of different sizes into groups or grade
whose characteristic is the particles therein are
more or less nearly the same size, that all have
passed an aperture of certain dimensions and failed
to pass through some smaller aperture.
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Slurry - A slurry is a suspension of solids in water. Coal
slurries range between about 3 percent and 50 per-
cent solids and are the form in which coal is fed to
cyclones, hydrocyclones and flotation cells. Slurry
frequently refers to a suspension of only one type
of solid, such as raw coal in water.
Specific Gravity - Specific gravity is the weight of a substance as
compared to the weight of an equal volume of water.
From the standpoint of coal preparation, it is the
single most important physical property of coal.
With the exception of froth flotation, all the
methods of coal preparation in general use are
dependent upon the difference in specific gravity
between the desired coal and its associated
impurities.
Specific Gravity
of Separation
Specific Gravity
Units
Stacker
Stacker-
Reclaimer
The specific gravity of separation is read from the
distribution curve at the 50 percent ordinate and
is the specific gravity of material in the feed
that is divided equally between clean coal and refuse.
Specific gravity is described by a number, such as
1.5, which tells how much more an equal volume of
the substance weighs compared to water, 50 percent
or half again as much in the "1.5" case. This
would be called 1.5 specific gravity units, and
1.6 would differ from 1.5 by 0.1 specific gravity
units (S.G.U.).
A stacker is a heavy, usually rail mounted machine
used to form material storage piles. The machine
has a crane-like inclined boom that is sometimes at
a fixed inclination but often can be raised or
lowered to minimize dropping distance during
operations. A belt conveyor is mounted on the
boom to transport material from a receiving point,
which may be from a moveable tripper on a feeding
belt conveyor. A radial stacker has a fixed feed
point which is also the pivot point about which
the radial stacker rotates to form, in this case,
a crescent shaped storage pile.
A stacker-reclaimer is first of all a stacker.
However, the boom belt conveyor is reversible and
a rotating bucket wheel is mounted at the end of
the boom to reclaim materials from the pile. With
a stacker-reclaimer the boom must necessarily raise
and lower and usually pivots around the stacker
mode boom belt loading point also. The reclaimer
647
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Stacker-
Reclaimer
(continued)
Steam Coal
function is controlled by an operator in a cab
that travels with the stacker-reclaimer. Stacker-
reclaimers usually travel in-line and are sometimes
mounted on caterpillar tracks for additonal mobility.
This refers to virtually all coals that can be
productively burned to produce steam in a boiler
operation including lignite and what could otherwise
be used as metallurgical coal. A very high ash
coal (at say 70% ash) would not qualify. Coals with
lower mositure and ash have more heating potential
when burned.
Stratification
Sulfur
Suspension
Total Misplaced
Material
Stratification is a term applied to the conditions
that exist when the motion is applied to a
material on a screen deck. The motion causes the
finest particles to go to the bottom with each
excessive larger size located in "stratis" or
layers up to the top surface where the largest
particles are.
Sulfur occurs in coal in four basic forms; that is,
native or free sulfur, as sulfate sulfur, as pyritic
sulfur and as organic sulfur. Native or free sulfur
is rare in coal and may be neglected when speaking
about coal preparation. Weathering increases the
percentage of sulfate sulfur in the coal. It is
removed by normal wet coal preparation methods.
Organic sulfur is a part of, and is linked with, the
coal itself. The amount of organic sulfur present
defines the theoretical lowest limit to which a
coal can be cleaned for sulfur removal by physical
methods. The percentage of organic sulfur in coal
is determined by difference (not directly) from
analyses. Finally, pyritic sulfur exists in two
dimorphs of ferrous disulfide (FeS2) that is as the
minerals pyrite and marcasite. Pyritic sulfur is
common to all coals and occurs both on the macro-
scopic and microscopic levels. It is determined
directly from analyses and is the form of sulfur
removed from coal by physical preparation methods.
A suspension is a system consisting of a solid
dispersed in a liquid or gas, usually in particles
of larger than colloidal size. The particles are
mixed with but undissolved in the fluid. Solids
dispersed in a solid are called "solid inclusions".
Total misplaced material is the percentage of feed
which reported to the wrong product. For sharp
648
-------
Tramp Iron
Trommel Screens
Ultimate
Analysis
Undersize
Volatile Matter
separations, the misplaced material is that material
having specific gravity values close to the specific
gravity of separation and, thus, correlates with the
amount of near gravity material.
Bolts, shovel teeth, picks and other uncrushable
metal are termed tramp iron.
Trommel screens are similar to revolving screens
except that they are carried on a thru-shaft instead
of rollers.
Ultimate analysis supplies information on the
elemental composition of coals in terms of ash,
carbon, hydrogen, nitrogen, oxygen and sulfur. The
analysis may be mde on an undried sample ("as-
received" basis) or on a dried sample ("dry" basis).
With the undried sample, the free moisture of the
coal is reported as part of the hydrogen and as
part of the oxygen. Thus ultimate analysis should
always be specified as being on an as-received
basis or on a dry basis. The analysis includes:
the determination of carbon and hydrogen
in the material as found in the gaseous
products of its complete combustion, the
determination of sulfur, nitrogen and ash
in the material as a whole, and the
estimation of oxygen by difference.
Details of a frequently used method of ultimate
analysis can be found in U.S. Bureau of Mines
Bulletin 638, pp. 3-5 for moisture and ash, and
pp. 7-11 for carbon, hydrogen, nitrogen, sulfur and
oxygen (oxygen by difference). A similar
ultimate analysis will be found in ASTM D271-68,
"Laboratory Sampling and Analysis of Coal and Coke".
The procedure sections in the ASTM specification
are: Section 6 through 11 for moisture and ash;
Sections 18 through 25 for sulfur; and Sections 30
through 42 for carbon, hydrogen, nitrogen and
oxygen. In both of the above ultimate analysis
procedures, which are comparable, the ash and
moisture in "proximate analysis" is the same
ash and moisture used as part of the ultimate
analysis.
Undersize is a material that passes through a
given screen opening.
A measure of the gases which are formed from coal
on heating to a temperature around 950° C. in
proximate analysis, but excluding moisture.
649
-------
Washability
Data
Weir
Yield
Yield Error
Zeta Potential
The specific gravity fractions resulting from the
specific gravity analysis of a coal are weighed
and analyzed for ash and sulfur content and these
three types of information provide the basis for
calculating the washability data. The data are
plotted as washability curves. 'The washability
curves predict, for separation of the given coal
at a given specific gravity: (1) percentage of
the feed that will be recovered as clean coal,
(2) the percentage of feed that will be refuse,
(3) the ash analysis of the clean coal, (4) the
ash analysis of the refuse and (5) the highest
ash expected in the particular density fraction
of the clean coal. Predictions for sulfur, as
well as ash, can be included in sulfur analysis
data is available, but these are not yet reliable.
A weir is a notch over which liquids flow and which
is used to measure the rate of flow. A dam across
the stream for diverting or measuring the flow.
(Note: The essential difference between an
orifice and a weir is implicit in the expression:
water flows through an orifice but over a weir.)
Yield is also called "yield of coal" or "yield of
washed coal". Yield is designated by the percent
by weight of raw coal that reports to the clean
process or to an equipment product. Sometimes the
percent by weight of a certain feed coal that
reports to a given process or equipment product
is called yield, but then the feed and the product
should be specifically designated.
The difference between the yield of coal actually
obtained and the theoretical yield at the ash
content of the washed coal is termed yeild error.
Zeta potential, or electrokinetic potential is
the potential difference across an electric
double layer, usually in a liquid next to a solid
surface. The zeta potential concept is made
evident in a phenomenon known and electrophoresis.
Electrophoresis is defined by the migrating rate
of electrokinetically charged particles which are
suspended in a liquid, toward an electrode of
opposite charge in a DC voltage (electrical force)
field. Different particles typically have different
rates of migration. The migration speed is
directly proportional to the magnitude of the zeta
potential of the particles and to the DC voltage
650
-------
Zeta Potential applied. The migration speed is inversely
(continued)proportional to the distance between the electrodes.
The potential is important in flocculation
phenomenon, a factor to be considered in the flota-
tion process and may be significant in other coal
preparation equipment where individual particles
are processed in fluids.
651
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THIS PAGE INTENTIONALLY LEFT BLANK
652
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APPENDIX II
Coal Waste Disposal Questionnaire
653
-------
Site Number
Dace
COAL-WASTE DISPOSAL INVENTORY
QUESTIONNAIRE
We need your help to develop a complete and accurate coal-waste disposal inventory. Before
completing the questionnaires enclosed in this folder, along with an aerial photograph of
your site, please, read the following definitions and explanation.
DEFINITIONS
Site A geographical location of past or present waste producing unlt(s) such as
a mine, mill, plant, and/or smelter and its associated waste disposal sys-
tem or complex.
Disposal Area A general area or plot of land within the site that is used as a place for
long-term storing cr disposing of waste materials
Waste Deposit A structural entity consisting of a dump(s), an Impoundment(s), or a combin-
ation of a dump(s) and/or impoundment(s) within a disposal area
Dump A permanent or long-term accumulation of mine, mill, plant, and/or smelter
waste materials, on or In the earth, not capable of Impounding liquid
Impoundment A depression; excavation; permanent or long-term accumulation of mine,
mill, plant, and/or smelter waste materials; or other facility, on or In
the earth, capable of Impounding liquid; an impoundment Includes:
Retaining Elements—embankments, depressions, excavations, etc.
Retained Elements—liquids, sludge, slurries, etc.
Potential Retention—storage space able to retain liquids, sludge, slurries,
etc.
EXPLANATION
Simple forms of coal-waste dumps and impoundments are illustrated Inside this folder. Most
of the more complex waste deposits are combinations and variations of the simple forms, but
some complex forms defy categorization—these waste deposits are designated by type number
VI if they are not capable of impounding liquid or sludge and by type number XI if they are
capable of impounding liquid or sludge. (Use the back of the Basic Data Form, Section 1.4,
for sketches of their plans and sections.)
Each site has been given an inventory number. In addition, at each site, waste deposits are
numbered sequentially, with letters added to the numbers for simple forms that are combined
into a structural entity. At the plant site shown in the aerial photograph on the back of
this folder, for example, the ridge dump was numbered 01; the two side-hill dumps under the
aerial tramway were numbered 02 and 03; the massive cross-valley structure was numbered 06
with the valley-fill dump at its upstream end designated 04-A, the three cross-valley im-
poundments designated 04-B, 04-C, and 04-D, and the side-hill dump along the right-hand side
of the valley designated 04-E; the waste heap or stock pile alongside the railroad track was
numbered 05; the two diked ponds beside the plant were numbered 06 and 07; and what may be
a waste heap and/or ponds was numbered 08. Two small earth dams near the ridge-dump toe not
shown in the photograph were numbered 09 and 10.
On the aerial photograph of your site in this folder, waste deposits have been classified by
type and assigned numbers, with and without letters, as seemingly appropriate. We need to
know: (1) if all of these waste deposits belong to your site, (2) if the classifications
assigned them on the basis of the photograph are, indeed, reasonable ones, (3) if there are
any other coal-waste deposits at your site, and (4) basic information about the structures.
Whether a simple form stands alone or in combination with other simple forms, a column in
the Basic Data Form should provide information on each simple coaJ-waste deposit form at your
site. Please, complete the Basic Data Form(s), Section 1.4, enclosed in this folder, provid-
ing the data called for in each box marked by a check. If any of the structures do not be-
long to your site, write "Not at this site" in its column, and Indicate to whom it belongs.
If there are other coal-waste deposits at your site, Include them on the Basic Data Form by
assigning numbers, letters, and type classifications and providing appropriate data In blank
columns on the form.
Complete Section 2.0 for each column In the Basic Data Form, providing information on the
dump tu retaining element of the Impoundment. Complete Section 3.0 for Impoundments only,
that Is for each column in the Basic Data Form with a type number Vll through XI. If in-
formation called for is the same for more than one structure at a site, refer to the earlier
data by number and letter.
W.fl.WAHlffi
1023 CORPORATION WAY. PALO AITO. CAlllflRNIA <»4,li).| • ,4151 953 f^yj
654
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SIMPLE DUMP FORMS
TYPE OF DUMP GENERALIZED PLAN CROSS SECTION AB
LONGITUDINAL CROSS
SECTION CD
VALLEY-FILL TYPE I
rA
CROSS-VALLEY TYPE II
A-i
a/a' b/b1
LRI
SIDE-HILL TYPE III
VIE* »
c d
VIE*
*
RIDGE TYPE IV
be
HASTE HEAP TYPE V
\
a b c d
e f g h
\
655
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Site Number
Date
1.0 OWNERSHIP AND SITE IDENTIFICATION
1.1 Site Name
site name
mailing address
city, state, zip
phone number
1.2 Physical Address
nearest town county
miles from town direction on road number state
1.3 Site Owner
Is the disposal area owned by the site operator?
yes no
mine/plant owner name
mailing address
city, state, zip
phone number
parent organization
mailing address
city, state, zip
phone number
1.4 Basic Data Form
Whether a simple form stands alone or in combination with other simple forms, a column In
the Basic Data Form, Section 1.4, should provide information on each simple coal-waste de-
posit form at your site. Please, complete the Basic Data Fonn(s) that are attached, provid-
ing the data called for in each box marked by a check. If any of the structures do no be-
long to your site, write "Not at this site" in its column, and indicate, if possible, to
whom It belongs. 1C there are other coal-waste deposits at your site, Include them on the
Basic Data Form by assigning numbers, letters, and type classifications and providing appro-
priate data in blank columns on the form.
Complete Section 2.0 for each column In the Basic Data Form, providing Information on the
dump or retaining element of the Impoundment. Complete Section 3.0 for impoundments only,
that is for each column in the Basic Data Form with a type number VII through XI. If
information called for Is the same for more than one structure at a site, refer to the
earlier data by deposit number and letter.
W.A.WAHIN
0 nuoULInllU I02J CORPORJHON Wlr. P«10 «IIO fAIIFORNII IIJDJ . «1S19636?»
656
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Site Number
Date
SECTION 1.4—BASIC DATA FORM
Provide the data called for in each box marked by a check.
Number, letter, and classify and provide similar data for
other coal-waste deposits at your site. Refer to sketches
inside the folder for definitions of points.
Deposit Number
noposit Letter
Typo
novations — ft msl or rotative to dowm:tream to
a
..'
h
h'
d
c
f
g
h
.1
a1
b
b'
'•
d
c
f
B
h
ab
a'b1
bi-
rd
do
o.l
Berns-Slope
Elevation
Horizontal
Slope
elevation
Horizontal
Maximum Storage Pond Area—ai-res;
SVrn-.il Storage Pond Area— .lores
Normal U'alor Depth at Kmb.inkmont K.IOO--II
Normal Sludgo Depth at Kmhankmont K.-ICO--I t
i vost Sliapo--Hou-nj;tr.>an aroli, S-shrtpPd. ol.:.
— two or HHIV siRiiif
--two or imir
-------
SECTION 2.0
Complete for each column in the Basic Data Form,
providing information on the dump or retaining
element of the impoundment. If information called
for is the same for more than one structure at your
site, refer to the earlier data by deposit number
and letter.
Site Number
Deposit Number
Deposit Letter
Date
2.1 Name and Location
deposit name
o '
USGS 7.5' Quadrangle
2.2 Deposit Status
north
Rate of past, present, and planned deposition from initiation to abandonment:
From-to (mo/yr)
Tons/day
From-to (mo/yr)
Tons/day
Is deposit burning or' has it ever burned?
burning burned never unknown
burned
Is deposit being reworked or has it '
ever been reworked? being reworked never unknown
reworked reworked
2.3 Deposit Foundation
Describe type, structure, weathering, and drainage of the foundation:
Same as
Same as
letter
Pond
Prior to construction, was foundation: Yes
Cleared of vegetation?
Stripped" of overburden?
Embankment
No Unknown Yes No Unknown
Inactive mine
Are there any mines under the disposal area? Operating mine
Abandoned mine Potential mine If so, how many feet below the waste
If not, what is approximate distance to the nearest
deposit is it located?
underground mine tunnel/drift?
If the deposit is or has teen an impoundment, has the embank-
ment been expanded in the upstream direction so that it may 'yes
be partially founded on silt or sludge?
2.4 Surficial Condition of Deposit
Are plants and/or trees growing on the deposit?
If so, do they have a normal attitude?
Are there any volcano-like boils on the deposit?
Yes No
Same as
letter
ASSOCIAIES
1023 CORPORATION WAV. PALO AllO. CALH08NIA 94303
658
-------
2.4 Continued Yes No
Are there any sinkholes or other depressions on the deposit's surface?
Are there any surface cracks?
Is there any evidence of settlement?
Is there evidence of erosion?
If so, describe:
2.5 Deposit Movement Yes Xo
Were settlement markers Installed?
Is there any history of slope movement?
Is there any evidence of the following: Slides Slumps
Flows Bulges Heaving Loose/rolling rocks
Movement beyond the toe
other other
2.6 Consequence of Deposit Failure Yes No
Is any property (railroad, highway, power line, etc.) threatened?
Is the deposit positioned so that if it were to slide or move it could
block a watercourse?
Are any people working in a position directly threatened by potential Number None
slides or other movement?
Are any people living in a position directly threatened by potential
slides or other movement?
2.7 Deposit Material and Source
What coal seams were or are being mined nnd what percent of e.ich by volume is involved
in this deposit:
Coal Seam Other Name Percent
What mining method(s) was or Is being used?
About what percent by volume of the deposit is: Mine refuse rock Z Coal culm
Mill refuse Z Red dog Z Z
other
Which of the following equipment was or is being used to clean the coal?
Jigs Air tables or cleaners Flotation Heavy media
Water tables Wet cyclone Dry cyclone
other
2.8 Construction Method
Systematic Compaction Same as
Spreading Refuse Layers Layers
Deposition Gravity Mechanical None Only Clay Other Unknown
Aerial tram number
Conveyor belt
Dump truck letter
659
-------
Site Number
SECTION 3.0
Complete for each impoundment, that is for each Deposit Number
column in the Basic Data Form with a type number Deposit Letter
VII through XI. If information called for is the
same for more than one impoundment at your site,
refer to earlier data by deposit number and letter.
3.1 Impoundment Status
Rate of past, present, and planned inflow from initiation to abandonment —
From wash plant:
From-to (mo/yr)
Gallons/day _ __
7. Solids by weight .
From mine drainage:
From-to (mo/yr)
Ual Ions/day
Z Solids by weight:
Was embankment breached or is it to be breached upon discontinuation
of impoundment operations? yes no
3.2 Outlet Facilities
Describe type, dimensions, location, and elevation (with respect to minimum
embankment crest elevation) of:
Outlet conduits:.
Open-cut spillway:.
Diversion ditches:.
Other outlet facilities:
If there is an open-cut spillway, is it cut into firm ruck? —.
yes
If not, describe:
Describe downstream erosion protection:
Describe upstream erosion protection:.
ASSOCIATES
IO?J CORPORA I ION WAY. PALO Al HI CAllFOflNIA «H.t(U
660
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3.3 Seepage through the Embankment
Seep Tr irk]e Flow Stream
Location of Seepage- None (0.1 gpm) ( 1.0 ^pm) ( JO gpm) ( 10 gpm)
Right nbutment contact
Left abutment contact .
Foundat ion-toe contact
Downstream shell
If there is seepage on downstream face, what height is it above the toe?
feet feet feet
Are there any visible sinkholes in impounded sludge?
yes no
If so describe size and location: ,
3.4 Impoundment Hydrology Same as
What is the approximate drainage area? :
square miles number
About what percent of the watershed is covered with vegetation? %
devoted to commercial, industrial, or residential use? % letter
stripped of vegetation for mining purposes? %
otherwise stripped of or lacking vegetation? _%
3.5 Hydraulics jnd Consequences of Failure Same as
To complete the following table, use these character codes to describe down-
stream watercourse characteristics: number
1 = improved channel sect ion
2 = well-defined confined natural channel letter
3 = reasonably well-defined and confined natural channelf
4 = poorly defined channel with extensive areas subject to overbank flooding
Numhnr un Flood Plain
Distance
Character (mile) Dimensions Schools/ Com/Indus
Code From To • (feetj Dwellings Churches Establish Other
661
-------
TYPE OF IMPOUNDMENT
SIMPLE IMPOUNDMENT FORMS
GENERALIZED PLAN CROSS SECTION AB
LONGITUDINAL CROSS
SECTION CO
CROSS-VALLEY TYPE VII
a/a1 b/b1
d e
SIDE-HILL TYPE VIII
A
ab
e fg
DIKED POND TYPE IX
bcri
INCISED POND TYPE X
a b
-I I
t
a' b1
662
-------
iT
VV
663
-------
THIS PAGE INTENTIONALLY LEFT BLANK
664
-------
APPENDIX III
Washability Curves
and
The Intrepretation of Float-and-Sink Data
665
-------
APPENDIX 3
Washability Curves and the
Interpretation of Float-and-Sink Data
(Adapted from: G.D. Coe, An Explanation of Washability Curves
For the Interpretation of Float-and-Sink Data on Coal, U.S. Bureau of
Mines Information Circular No. 7045 (Washington: U.S. Department of
the Interior Library, 1938), 10pp.)
A raw-coal sample is float-and-sink tested as described in
Section V.D.2.d.). The Products resulting from the float-and-sink
separations, after they have been dried, are weighed and analyzed
for moisture and ash. The weights are calculated to percentages and
the ash analyses to percentages on the moisture-free basis. These
data are tabulated as shown in the first five columns of Table 1.
TABLE 1. - Arrangement of Float-and-Sink Data
Description
(1)
Coal from the
Pratt bed,
Warrior
Field,
Alabama
Specific
Gravity
(2)
Float on 1.27
1.27 - 1.30
1.30 - 1.38
1.38 - 1.50
1.50 - 1.70
1.70 - 1.90
Sink in 1.90
Weight
Kg.
(3)
5.10
4.20
2.50
.79
.48
.45
1.25
14.77
Weight
%
(4)
34.5
28.4
16.9
5.4
3.3
3.0
8.5
Ash,-'/
%
(5)
2.8
3.9
8.8
16.9
30.6
46.2
71.3
Cum.
Weight
%
(6)
34.5
62.9
79.8
85.2
88.5
91.5
100.0
Cum. v
Ash,^
%
(7)
2.8
3.3
4.5
5.3
6.2
7.5
12.9
I/Moisture Free basis
The values in Column 6, headed "Cumulative weight, percent," are
in each instance the sum of all the preceding weight percentages. For
example, the first value recorded in the "Cumulative weight, percent"
666 .
-------
column is the same as the first value in the "Weight, percent" column;
the second value is the sum of the first two weight percentages; the
third is the sum of the first three; and so on.
The values listed in column 7 of Table 1 have been computed and
represent, in each instance, the ash analysis of the total float-coal
on the corresponding specific gravity shown in column 2. For instance,
the total coal floating at 1.27 specific gravity analyzed 2.8 percent
ash; at 1.30 specific gravity, the cumulative ash analysis would be
3.3 percent at 1.38 the cumulative ash would be 4.5 percent; and so on.
The last value, 12.9 percent, would be the analysis of the total coal
sample, including the sink in the liquid of 1.90 specific gravity. The
calculation of the cumulative ash percentage is based on the equation:
"weight, percent" x "ash, percent"
2——*• —£• = units of ash
100
where "units" means parts in the number of parts expressed by the
corresponding weight percentage.
Referring again to the data of Table 1, the cumulative ash for
the float-on-1.27 fraction is the same as the corresponding percentage
listed under "ash, percent". The next cumulative ash value may be
calculated in the following manner: In the float-on-1.27 fraction
there is 34.5 x 2.8 or 0.9660 units of ash; in the 1.27-1.30 fraction
100
there are 28.4 x 3.9 or 1.1076 units of ash. The sum of these,,or
100
2.0736, is the units of ash in the total material lighter than 1.30
specific gravity, which, as shown by column 6, comprises 62.9 percent
by weight of the sample. Since "weight, percent" x "ash, percent" =
100
"units of ash", then "units of Ash" x 100 ~ "weight, percent" = "ash
percent", and 2.0736 x 100 4- 62.9 = 3.3 percent, the average ash
content of the float-on-1.27 fraction combined with the sink-on-1.27
and-float-on-1.30 fraction, or the total float on the liquid of 1.30
specific gravity. The calculations for the third recorded cumulative
ash percentage are:
667
-------
(34.5 x 2.8) + (28.4 x 3.9) + (16.9 x 8.8)
100 4- 79.8 = 4.5
100 100 100
percent. This system of calculation is continued for all of the
specific-grav-fractions down to and including the sink in 1.90.
In constructing washability curves, cross-section paper with
centimeter and millimeter divisions is used. This paper should be at
least 21 by 25 cm in size. The ordinate and abscissa scales should
be in the form shown in Figure 1. An almost indispensable piece of
equipment is a No. 48 Copenhagen ship curve.
A. Cumulative Curve
• The first curve to be plotted is the one called "cumulative",
showing the yield of float coal resulting from a 100-percent efficient
separation at any selected cumulative, or average, ash percentage.
The curve is outlined in Figure 1 by plotting the percentages found
under columns 6 and 7 in Table 1. A smooth curve is drawn through
the resulting points.
B. Elementary Curve
Mathematically, the elementary curve is a derivation of the
cumulative curve and gives an indication of the rate of change of
the ash content at different yields. In other words, the elementary
curve is intended to indicate the average ash percentage in the
highest ash particle group included in a float-coal product, for any
given cumulative ash percentage. The elementary curve can be
established by the following method.
A rule for calculating points on the elementary curve directly
from the float-and-sink data may be expressed as follows:
One half of the "weight, percent" of the specific-
gravity interval involved, plus the "cumulative weight,
percent" of all material of lower specific gravity, is
plotted against the ash content (not cumulative ash)
of the specific gravity interval involved.
(Note that columns 4 and 5 in Table 1 show that 34.5 percent of
the total coal is of lower specific gravity than 1.27 and that the
668
-------
DIVISIONS USUALLY MADE •
1 CENTIMETER
iO.10 SPECIFIC GRAVITY DISTRIBUTION CURVE
A REPRESENTATION OF
ACTUAL PERCENTAGE OF
COAL NEAR GIVEN SEPARAT-
ING SPECIFIC GRAVITY
CUMULATIVE ASH TO
CUMULATIVE FLOAT COAL
ASH PERCENT REPRESENTA-
TIVE AT HIGHEST SPECIFIC
GRAVITY PORTION
90
CUMULATIVE
WEIGHT OF
FLOAT COAL
AT GIVEN
SPECIFIC GRAVITY
100
0246
2.2
10
2.1
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
I
CUMULATIVE ASH, PERCENT
20 30 40 50 60 70 80 90 100
ELEMENTARY ASH, PERCENT
2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2
SPECIFIC GRAVITY
(APPENDIX 3) Figure l.-Coal-washability curves,
669
-------
average ash content of this product is 2.8 percent. Obviously, every
particle of coal included in this, product does not contain exactly 2.8
percent ash. The analysis does not show what the ash range is, but
merely that these particles of coal collectively contain 2.8 percent
ash.)
Application of the above calculation rule to the values recorded
in Table 1 results in the following calculations:
34.5
* or 17.25 percent cumulative weight plotted at 2.8% elementary ash.
-~— or 14.2 + 34.5% = 48.7% cumulative weight plotted at 3.9%
elementary ash.
p C
-j- or 4.25 + 91.5 = 95.75% cumulative weight plotted at 71.3 elem. ash.
Thus three points are shown calculated which serves to illustrate
the method of determining points for the elementary curve. The
elementary ash curve is an indication of the ease with which coal may
be cleaned. Flat slopes mean an easy separation without large changes
in the amount of ash removed with small changes in process separating
specific gravity.
C. Specific-Gravity Curve
The specific gravity curve in Figure 1 shows the yield of float
coal for a perfect separation, meaning laboratory conditions, at any
specific gravity within the range of gravities of the float-and-sink
tests.
This curve is constructed by plotting the specific gravities
listed in column 2 of Table 1 against the corresponding cumulative
weight percentage, column 6. In this manner, a series of points
plotted from the float-and-sink data are connected to form a smooth
curve.
670
-------
D. The Plus-and-Mimis 0.10 Specific Gravity-
Distribution Curve
The +^ 0.10 specific gravity-distribution curve in Figure 1 shows
the percentage by weight of the coal that lies within plus 0.10 and
minus 0.10 specific-gravity units at any given specific gravity. For
instance, the +_ 0.10 value at 1.40 specific gravity is the percentage
of the total coal that lies within the 1.30 to 1.50 specific gravity
range. At 1.45 specific gravity, the +_ 0.10 value is the percentage
between 1.35 and 1.55 specific gravity and so on.
The H^ 0.10 specific gravity distribution curve is constructed in
the following manner: The yield at 1.30 specific gravity is subtracted
from the yield at 1.50 specific gravity as read from the specific
gravity curve in Figure 1. To compensate for varying amounts of
high-gravity materials, especially slate and other rock, the numerical
difference in the yields is divided by the yield at 2.00 specific
gravity. The resulting adjusted percentage is plotted at 1.40 specific
gravity. The reason for dividing the difference in the two yields
by the yield at 2.00 specific gravity is that the material of higher
specific gravity than 2.00, because of its rapid settling rate, would
not interfere with the separation between washed coal and refuse at
normal specific gravities. Failure to make this correction would
result in the absurd condition where the addition of roof rock to
the washery feed would apparently decrease the difficulty of the
separation because it would decrease the percentage of material
within the +_ 0.10 range. The next point is determined by subtracting
the yield at 1.35 specific gravity from the yield at 1.55 specific
gravity. This difference, divided by the yield at 2.00 specific
gravity, is plotted at 1.45 specific gravity. In this manner points
are plotted at specific-gravity intervals of 0.05 throughout the range
from 1.40 to 1.80 specific gravity.
E. Method of Reading the Washability Curves
Because all of the curves have a common ordinate, values from one
of the curves may be expressed in terms of any of the others. This is
671
-------
illustrated by the broken lines in Figure 1 where some additional
points not found in Table 1 have been plotted. Assume that the coal
to which the curves of Figure 1 apply is of a size range suitable for
concentrating-table concentration. A reading of 10 percent on the
+^0.10 specific gravity-distribution curve represents the normal
maximum difficulty at which a wet table is capable of effecting an
efficient separation.. At 10 percent cumulative weight, Figure 1
shows a horizontal broken line that intersects the ^0.10 curve at
1.452 specific gravity. The vertical broken line at this specific
gravity intersects the "Specific Gravity" curve at 83.9 percent
cumulative weight, and the horizontal broken line at 83.9 percent
cumulative weight is shown to intersect the "Elementary" curve at 19.5
percent ash and the "Cumulative" curve at 5.0 percent ash. In other
words, the curves predict that a concentrating table, if expertly
operated and if other conditions are favorable, should be capable of
washing this coal efficiently to 5.0 percent ash with a theoretical
yield of 83.9 percent. Included in the washed coal would be particles
containing as high as 19.5 percent ash. The efficiency of the
separation is the ratio of the actual yield to the theoretical or
float-and-sink yield, and should be about 95 percent. It is not
unusual for a table to operate at 97 to 98 percent efficiency, but
95 percent represents the usual average when the object is to produce
as clean a washed coal as possible. Thus, the actual yield of
5.0 percent ash washed coal that could be expected is 95 percent of
83.9, or 79.7 percent of the total raw coal feed.
672
-------
APPENDIX IV
Performance Criteria
673
-------
APPENDIX IV
Performance Criteria
Efficiencies as used herein refer to the body of performance
criteria which is utilized to evaluate the separation of a feed, as
effected by a washing device, into a salable product and a reject.
The quantity and quality of clean coal produced by a cleaning
unit are of primary interest to the operator because they determine
the economics of the operation. However, both quantity and quality
are influenced directly by the density composition of the feed and
by the density of the separation. Therefore, the use of yield and
ash content to draw direct comparisons between similar cleaning units
treating dissimilar feeds or making separations at dissimilar
densities is not valid. Nevertheless, yield and ash content are of
such vital importance to the operator that to be useful all other
criteria should have a direct bearing on them.
Performance criteria used to evaluate cleaning efficiencies are
of two principal types: those dependent upon the density composition
of the feed, and those substantially independent of the density
composition of the feed. A distribution curve is important in
performance analysis and will be discussed in connection with inde-
pendent criteria.
A. Criteria Dependent on Density Composition of Feed
Performance criteria that depend on both the washability
characteristics of the coal being treated and the sharpness-of-
separation achieved by the washer are called "dependent criteria" and
include recovery efficiency, misplaced material, ash error, and
yield error.
a) Recovery efficiency is defined as the ratio, expressed as a
percentage, of the yield of washed coal to the yield of float coal
of the same ash content shown to be present in the feed by the
specific-gravity analysis.
674
-------
b) Total misplaced material is that percentage of the feed which
reports to the wrong product. For sharp separations, the misplaced
material is principally composed of that material having specific
gravities close to the specific gravity of separation and thus is
strongly influenced by the amount of near-gravity material present.
Near-gravity material is defined as that percentage of material in the
feed +_ 0.10 specific-gravity units from the specific gravity of the
separation.
c) Ash error is the numerical difference between the actual and
theoretical ash contents of washed coal at the yield of washed coal
obtained. Ash error takes into account both the amount and quality of
improperly treated material, and thus is a direct measurement of
impairment in ash content.
d) Yield error is the difference between the yield of coal actually
obtained and the theoretical yield at the ash content of the washed
coal. Yield error is related arithmetically to efficiency; they
simply express the same thing in different terms.
Ash error and yield error are closely related to recovery
efficiency and are of special interest inasmuch as they indicate the
margin by which actual recovery and ash content of the clean coal
product approach the theoretical recovery and ash. Because of the
arithmetical relationship between yield error and efficiency, greater
yield errors accompany higher yields for any given efficiency.
B. Criteria Independent of Density Composition of Feed
Criteria which are characteristic of the washing unit performance
and are substantially unaffected by the density composition of the
feed are called "independent criteria" and include probable error,
error area, and imprefeetion. Often referred to as sharpness-of-
separation criteria they are obtained from the distribution curve.
a) Distribution curve, the distribution curve plots the percentage
of each density fraction of the raw coal that reports to the washed
coal against the mean of the density fractions. It can be used to
675
-------
describe the characteristics of actual process equipment. See
Figure 1 where a distribution curve has been plotted based on data
obtained from a heavy media vessel coal washer.
b) Probable error is obtained directly from the distribution curve.
It is numerically equal to one-half the specific-gravity difference
between the 25 and 75 percent recovery ordinates on the curve, and
thus is an indication of the slope of the distribution curve over a
large portion of its range.
c) Error area, the area between the actual distribution curve
obtained in practice and a theoretically perfect distribution curve
(a theoretically perfect distribution curve indicates 100 percent of
the raw coal lighter than the separating gravity going to washed coal
and zero percent of the raw coal more dense than the separating
gravity going to washed coal), is a measure of the total misplaced
material. The total misplaced material includes that material going
to clean coal that should have reported to refuse and that material
going to refuse that should have reported to clean coal. Error area
is a dimensionless number found when the distribution curve is drawn
to a uniform scale on which a unit of length that represents 2 percent
on the ordinate or weight scale will represent 0.1 specific gravity
units on the abscissa or specific gravity scale. The dimensionless
number, error area, is the area found as so many square units of the
length selected. The error area would be zero for a theoretically
perfect separation.
The two criteria, error area and probable error, represent
attempts to characterize the total distribution curve with a single
value. The convenience of such a procedure is appealing; and, in
general, good distribution curves are characterized by low error
areas and low probable errors, whereas poor distribution curves are
characteriezed by higher values of error area and probable error.
d) The imperfection factor is equal to the probable error divided
by the specific gravity of separation (the 50 percent recovery point
676
-------
from the distribution curve) minus the actual specific gravity of
the separating medium. For jigs, tables, rheolaveurs and other washers
employing water as the separating medium the actual specific gravity of
the separating medium is taken to be 1.0 specific gravity. In
correcting for the increase in probable error by division using an
increasing specific gravity of separation, imperfection provides a
unique parameter that characterizes a particular cleaning device
regardless of the separating specific gravity and density composition
of the feed. However, this value of imperfection is valid only for a
given size consist, feed rate, and quality of operation. In symbols:
d
Imperfection Factor = p ,
-—* , where:
a - d
s m
d = probable error
d = specific gravity of separation from the distribution curve. This
is the specific gravity where 50% of that specific gravity in
the raw coal reports to clean coal.
d = specific gravity of the separating medium used to wash the coal.
This specific gravity is taken as 1.0 for jigs etc., higher for
heavy media divices.
677
-------
1 1 1
Sp. pr. of scpar;i(inn - 1.35
Probable error - 0.025
-Error arc;i
^
~ 1
1
1
1
k_
o
O>
_o
ID
rj
.0
0
IX
1
1
|
1
1
^
b> —
V)
.Si
03 O
>- e-ti
u s
0 •-
c: u,
•n &
S.^
to _g
o y
o ri
s*b
ra
OS
y
- 17
»
-
-
/
...i j . i
1.3 1.4
sn.nnr CRAVITY
1.7
Distribution Curve for Dense Medium Vessel
Washing 4 inch by 3/8 inch Coal
678
-------
APPENDIX V
Calculation and Plotting
of Distribution Curves
679
-------
APPENDIX V
Calculation and Plotting of Distribution Curves
(Adapted from: M.R. Geer and H.F. Yancey, "Chapter 18: Plant
Performance and Forecasting Cleaning Results," Coal Preparation, eds.
Joseph W. Leonard and David R. Mitchell and Others; sponsored by the
Seeley W. Mudd Memorial Fund (Third Edition; New York: The American
Institute of Mining, Metallurgical and Petroleum Engineers, 1968).)
An example is perhaps the most satisfactory way to show how the
distribution data are calculated and plotted. Table 1 shows the
specific gravity analyses of the feed (composite), washed coal and
refuse made in the course of a performance test on a baum jig. The
analyses of the products are given in the usual way as percentages of
the products, and also as percentages of the feed. The latter are
obtained, of course, by multiplying the analysis of the product by the
yield of that product expressed as a decimal.
Strictly speaking, the distribution data should be plotted
against the mean specific gravity of the fraction—the specific gravity
at which half of the fraction would float and half would sink. In
practice, however, they are plotted against the midpoint of the
specific gravity range of the fraction. Assumptions are required in
plotting the lightest and heaviest fractions because they have no
exact limiting specific gravities. If 1.30 is the lowest specific
gravity used in the analysis, as frequently is the case, the point
for the float should be plotted at a specific gravity that is midway
between that of the lightest particle present and 1.30. A figure of
1.26 to 1.28 generally is used. Any error involved in making this
assumption generally has very little influence on the shape and
position of the curve; it becomes important only when the specific
gravity of separation is unusually low. If 1.80 is the highest
specific gravity in the analysis the sink is usually plotted at 2.20
or 2.30, depending on what is known about its composition. If the
highest specific gravity is 1.60 the proper position of the point
680
-------
(Appendix 5) TABLE 1. - Specific-gravity analyses and distribution data
00
Specific
gravity
Under 1.30
1.30 to 1.40
1.40 to 1.50
1.50 to 1.60
1.60 to 1.70
1.70 to 1.80
Over 1.80
Total
Specific gravity
analyses, percent
of product
A
Feed
0.2
76.1
11.2
3.6
1.8
1.4
5.7
100.0
B
Washed
coal
0.2
85.3
11.2
2.3
.6
.2
.2
100.0
C
Refuse
0.0
9.4
11.5
13.3
10.9
9.6
45.3
100.0
Specific gravity
analyses , —
percent of feed
D
Washed
coal
0.2
75.0
9.8
2.0
.5
.2
.2
87.9
E
Refuse
0.0
1.1
1.4
1.6
1.3
1.2
5.5
12.1
Disbritution, —
percent
F
Feed
100.0
100.0
100.0
100.0
100.0
100.0
100.0
G
Washed
coal
100.0
98.6
87.5
55.6
27.8
14.3
3.5
H
Refuse
0.0
1.4
12.5
44.4
72.2
85.7
96.5
a/ Column D obtained by multiplying column B by 87.9 percent, the yield of washed coal;
column E obtained in correcponding manner.
b/ Column G obtained by dividing column D by column A.
Column H equals 100 minus column G.
-------
must be lowered accordingly. An error made in selecting the projter
specific gravity at which to plot the sink sometimes has a significant
influence on the shape of the curve.
Generally the distribution curve is plotted directly against
specific gravity. In comparing curves having different specific
gravities of separation, however, they may be plotted against the
difference between the specific gravity of the fraction and that of
the separation.
In Europe it is common practice to plot the distribution curve
on either log probability or arithmetic probability paper in an
effort to obtain a straight line. The ordinate employed is always
percentage recovery on a probability scale, but the specific gravity
abcissa scale varies with the type of cleaning unit involved. For
dense medium cleaning units the abscissa scale is arithmetic. For
processes that employ water it is log d-1 (specific gravity of
separation minus one) and for pneumatic processes it is log d.
The advantages inherent in a straight-line plot are appealing.
The slope of the line is a measure of the sharpness of the separation
and the slope plus the specific gravity of separation combine to
characterize the complete curve. In principle, only two points are
required to plot the curve; thus a great deal of costly laboratory
work would be eliminated. In practice, however, it is found that
rarely can a set of distribution data be fitted to a straight line
without a loss in accuracy that often is rather large.
See Appendix 4 - Performance Criteria, in the section on Criteria
Independent of Density of Composition of Feed where there is
additional discussion of distribution data and associated distribution
curves.
682
-------
THEORETICALLY
PERFECT
DISTRIBUTION
CURVE
COLUMN "G" IN TABLE 1:
Percentage of the coal specific gravity fraction of
the feed which actually reports to clean coal.
100 percent or zero percent, but never an
intermediate value, represents the amount of clean
coal that .should report to a given specific gravity
fraction. Values are based on laboratory float-sink
analysis of both raw coal feed and clean coal
product.
1.2 1.3
1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1
PLOT DATA: DISTRIBUTION CURVE
SPECIFIC GRAVITY
683
-------
THIS PAGE INTENTIONALLY LEFT BLANK
684
-------
APPENDIX VI
Predicting Cleaning Results
Using Distribution Curve Data
685
-------
APPENDIX VI
Predicting Cleaning Results Using Distribution Curve Data
This appendix is adapted from U.S. Bureau of Mines Information
Circular 8093, "Evaluation of Washery Performance," by M.R. Geer and
H.F. Yancey which was published in 1962. It should be noted that
the prediction of cleaning results applies only to yield and ash
of clean coal, and not to the predicted sulfur content.
The projection of anticipated cleaning results—the yield and
ash content of the washed coal expected—is a prerequisite step in
the design of a new cleaning plant. Such predictions must be made
also in connection with the treatment of a new coal in an existing
plant, or in evaluating the effect of a proposed change in mining
practice that would alter the density composition of the raw coal.
Often these predictions are based largely on the judgment of the
preparation engineer. Experience in making similar separations in the
same type of equipment may provide a figure for recovery efficiency
that can be used in conjunction with the density composition of the
raw coal to calculate yield and ash content with acceptable accuracy.
However, if the separation is particularly difficult, involving an
unusually large amount of near-gravity material, or an excessive
amount of heavy impurity, the distribution curve recovery-efficiency
approach to predicting cleaning results is inadequate.
The distribution curve shows what proportion of each density
fraction of the feed will be recovered in the washed coal. It can be
used in predicting cleaning results. An example will illustrate the
technique employed. Suppose that market considerations indicate
that the new coal will require a separation at 1.50 specific gravity.
The following tabulation shows the specific-gravity analysis of
the new coal and the steps involved in the calculations.
686
-------
Specific
gravity
Under 1.30
1.30 to .40
1.40 to .50
1.50 to .60
1.60 to .70
1.70 to .80
Over 1.80
Total
Specific
gravity
difference^/
-0.22
- .15
- .05
+ .05
+ .15
+ .25
+ .70
— '
Distribution
factor,?/
percent
98.6
93.8
65.0
33.8
17.4
10.3
2.6
-
Raw
Weight,
percent
20.0
52.3
1J.4
3.8
1.9
1.0
9.6
100.0
COill
Ash.
percent
7.0
12.3
23.8
35.6
41.8
50.4
77.1
—
Washed
Coal^/
19.7
49.1
7.4
1.3
.3
.1
- .2
78.1
\J Difference between average specific gravity of fraction and specific gravity separation.
2/ Read from distribution curve of figure 2, using upper abscissa scale.
3/ As percentage of raw coal.
The float 1.30 has an assumed average specific gravity 0.22 lower
than the specific gravity of separation. Material of this density
difference would be distributed 98.6 percent to the washed coal.
Therefore, of the 20.0 percent of float 1.30, 19.7 percent (expressed
\
as a percentage of feed) would be recovered in the washed product.
Similarly, the next higher density fraction would have an average
specific gravity 0.15 lower than the specific gravity of separation,
and this would indicate a recovery of this material in the washed
coal amounting to 93.8 percent. Thus, of the 52.3 percent of 1.30 to
1.40 in the feed, 49.1 percent would be recovered in the washed
product. Similar calculations for each density fraction provide a
complete specific gravity analysis of the washed coal expressed in
percentage of feed. The sum of these percentages is the anticipated
yield of washed coal, in this example 78.1 percent.
The ash content of the washed coal (12.8 percent in this example)
is calculated by assuming that each of its density fractions will have
the same ash content as the corresponding fraction of the raw coal.
Generally this assumption is suffieiently accurate, although the ash
content of the heaviest portion of the washed coal ordinarily is
687
-------
substantially lower than the corresponding density fraction in the
raw coal. However, the amount of such material generally is so small
, that its assumed ash content is not significant. For example, in
the preceding sample calculation, the ash content of the washed coal
is reduced by only 0.1 percent if the ash value assigned to the sink
1.80 fraction is 50.0 instead of 77.1 percent.
A more serious error in calculating ash content may occur when
the density of separation falls within a fraction containing a large
proportion of the raw coal. If, for example, the separation is at
1.45 specific gravity, the portion of the 1.40 to 1.50 fraction
reporting to the washed coal will be somewhat lower in ash content
than this fraction of the feed, because it will include primarily
the lighter portions of the fraction. Error from this source can be
minimized by interpolating on the raw-coal washability curves to
subdivide the fraction in which the density of separation occurs into
intervals of about 0.02 specific gravity. In this way the gravity
range is so small that the difference in ash content between
corresponding fractions of the washed coal and raw coal is insignificant.
Obviously, the limitations on use of the distribution curve
cited earlier in this report apply when the curve is used in predicting
cleaning results. The principal limitation of concern is the necessity
of using a curve derived from treating coal having about the same size
composition as the one for which the prediction is being made.
Although the errors involved in employing a curve having a specific
gravity of separation varying from the desired value by 0.20 or more
generally are small, ideally a curve representing separation at about
the desired density should be used. If these few precautions are
observed the prediction of yield and ash content can be suprisingly
accurate.
688
-------
DISTRIBUTION CURVE
1.2 1.3 1.4 1.5
l.'6 l!7 !'8 1.9 2.0
SPECIFIC GRAVITY
2.1
2.2 2.3 2.4 2.5
689
-------
THIS PAGE INTENTIONALLY LEFT BLANK
690
-------
APPENDIX VII
Listing of Applicable ASTM Standards
691
-------
APPENDIX VII
List of Applicable ASTM Standards
ASTM D-3174
ASTM D-388
ASTM D-2234-68
ASTM D-431-44
ASTM D-440
ASTM D-2492
ASTM D-720
ASTM D-409-71
ASTM D-271-68
ASTM D-3173
ASTM D-2013-68
ASTM E-323-70
ASTM D-3172
ASTM D-197
ASTM D-410-38
ASTM D-311
ASTM D-3302
ASTM D-3177
ASTM D-3176
ASTM D-3175
ASTM E-ll-70
"Ash in the Analysis of Coal and Coke."
"Coals by Rank, Specifications for Classification Of."
"Collection of a Gross Sample of Coal."
"Designating the Size of Coal from its Sieve Analysis."
"Drop Shatter Test for Coal."
"Forms of Sulfur in Coal."
"Free-Swelling Index of Coal."
"Grindabiliyt of Coal by the Hardgrove Machine Method."
"Laboratory Sampling and Analysis of Coal and Coke."
"Moisture in the Analysis of Coal and Coke."
"Preparing Coal Samples for Analysis"
"Perforated-Plate Sieves for Testing Purposes"
"Proximate Analysis of Coal and Coke"
"Pulverized Coal, Sampling and Fineness Test"
"Sieve Analysis of Coal"
"Sieve Analysis of Crushed Bituminous Coal"
"Total Moisture in Coal"
"Total Sulfur in the Analysis Sample of Coal and Coke"
"Ultimate Analysis of Coal and Coke"
"Volatile Matter in the Analysis Sample of Coal
and Coke."
"Wire-Cloth Sieves for Testing Purposes."
The latest edition of the entire specification document appears
in the ASTM Annual Book of Standards, "Part 26 - Gaseous Fuels; Coal
and Coke," or may be obtained as individual publications from:
American Society for Testing and Materials
1916 Race St., Philadelphia, Pa. 19103
692
-------
APPENDIX VIII
Buying Guide
693
-------
This year's Buying Di-
rectory contains a handy
reference of up-to-date
equipment and services
that will help you
do your job more efficiently
and profitably.
The Buying Directory is
divided into two sections:
1. Product Classification—
An up-to-date alpha-
betical list of products,
materials and services,
and the companies
that offer them, starting
on this page. To help
you quickly find
the product or service,
the listing has been
alphabetized both by item
and company, and cross-
indexed. Note that some
product classifications
COAL AGE • September 1976
have numbered subdivisions
immediately under them.
These divisions are
designed to help you
identify quickly the
supplier of a specific
type of product. The
numbers following the com-
pany name thus refer to
the numbered items
appearing under the
product head. For example,
if you want to buy
corrosion-resistant
pipe, look under the general
heading PIPE and then
go through the subdivisions
until you find corrosion-
resistant, which has the
number 8 in front of it.
All companies in the
alphabetical listing
under PIPE and having
the number 8 after them
are suppliers of cor-
rosion-resistant pipe.
If a product does not
appear under one class-
ification, look for
the alternative listing.
2. Directory of
Manufacturers—Contains
in alphabetical
order, at the end of
this directory, the.
names and addresses of
the manufacturers,
suppliers and service
organizations appearing
in the Product
Classification section.
Advertisers appear
with bullets; see the
second to last page
of this issue for the
page number(s) of the
advertisement(s).
694
-------
ABRASION-RESISTANT
MATERIALS
A-S-H Pump. Div ol Envirotech Corp
American Alloy Ste«l. Inc.
Armco Div. Abe* Corp,
Anbury Industries, Inc
Sadall Co. Inc
Carborundum Company
Cincinnati RubDer Mlg Co, Ow ol Stewart-
Warner Corp
Columbia Steel Casting Co. Inc
Corhan Refractories Co. Div. ol Corning Glass
Works
Oetrick, M. H.Co.
du Pont be Nemours, E. I. 4 Co. Inc.
Durei Products. Inc, Nail. Wire Cloth Div.
ESCO Corp
Fairmont Supply Co.
Fiberglass Resources Corp
Galigher Co. The
Gates Rubber Co, The
General Electric Co. Carboloy Systems Depi
Goodrich. 8. F -Engineered Systems Co
Greenland Cast Basalt Eng. Co Ltd
Greengate Industrial Polymers Ltd.
Guyan Machinery Co.
Hensley Industries Inc.
Holt Rubber Co.. A Randron Dw.
International Alloy Steel Div., Curtis Noll Corp.
Jones & Laughlin Steel Corp.
Katenborn
Kanawha Mlg Co.
Lee Supply Co.. Inc.
Lmatex Corp. ot America
Lukens Steel Co.
3MCo
Manganese Steel Forge. Taytor-Wharton Co. Div.
of Harsco Corp.
Molded Dimensions Inc.
Norton Co
Oil Center Research
Poly-Hi. Inc.
Preiser/Mineco Div.. Preiser Scientific Inc.
Ryerson. Joseph I, I Son. Inc.
Shwayder Co.
Smith. A 0 Inland Inc Reinforced Plastics Div.
Steel Heddle Mfg. Co., Industrial Div.
Stellite Div.. Cabot Corp.
Stonhard. Inc.
Steady Co.
Stoody Co. WRAP Div.
Thomas Foundries Inc.
Trelleborg Rubber Co.. Inc.
Tricon Metals 4 Services, Inc
Trowelon. Inc.
U. S. Polymeric. Sub ot Armco Steel Corp
United States Steel Corp.
Waiai Industries Ltd.
Wall Colmonoy
West Virginia Bell Sales It Repairs Inc.
Wilmot Engineering Co.
Workman Developments. Inc.
AERIAL SURVEYING,
MAPPING, PHOTOGRAPHY
Aerial Map Service Co.
Aerial Surveys, Inc.
Aero Service Dw.. Western Geophysical Co. ol
Amer,
Berger Associates. Ltd.
Geometries
Gnffolyn Co.. Inc.
Numontcs Corp.
Westinghouse Electric Corp.
Wild Heerbrugg Insts. Inc.
AERIAL TRAMWAYS
Interstate Equipment Corp.
United Slates Steel Corp
ANALYZERS, COAL SULFUR
Beckman Instruments. Inc
KHD Industrieanlagen AG. Humboldl Wedag
Leco Corp
Perkm-Elmer Corp.
Preiser/Mmeco Div.. Preiser Scientific Inc.
ANALYZERS, GASES,
VAPORS, ATMOSPHERE
AT 0 Inr.
Ba( harach Instrument Co . Mining Div
Harnes f i>Kitieering Co
Beckman Instruments, Inc
Bullaid. I U Co
du Pont Of. Nemoms. f. I 4 Co Inc
Fdmonl-Wilson. Uiv ol Bcclon. Dickinson 4 Co
I isher Scientific Co
I eeds 4 Northrup Co
Mine Safety Appliances Co
National Environmental Insl Inc
National Mine Spruce Co
Perkm Elmer Corp
Preiser/Mmeco Div, Preiser Scientific Inc.
Scoll Aviation. A Div ol A-T 0. Inc
Taylor Instrument Process Control Div Sybron
Corp
Varian Associates
ANEMOMETERS
Alnor Instrument Co
Bacharach Instrument Co.. Mining Div.
CSE Mine Service Co .
Davis Instrument Mlg Co
Fisher Scientilic Co.
J-Tec Associates. Inc
Mine Safety Appliances Co
National Mine Service Co
Preiser/Mineco Div., Preiser Scientific Inc
BAGS
1. AIR Fll TERS. DUST COLLECTORS
, 2. AN-FO. NCN
3. EXPLOSIVES
A. TAMPING
5. SAMPLE
Aeroiall Mills Ltd.. (1)
American Air Filter Co. Inc. (I)
Atlas Povider Co.. (4)
Austin Powder Co. (2. 3.4)
Benns Co. Inc., (1.2, 3.4, 5)
Daniels. C. R. Inc.
du Pont de Nemours. E. I 4 Co Inc . (4)
Energy Packaging, Inc. (2. 3)
Fairmont Supply Co., (4)
Firestone Tire 4 Rubber Co. (1)
Hercules Inc.. (2. 3. 4)
Independent Eiplosives Co . (?. 3. 4)
Joy Mlg Co (UK )l!d. (1)
KHD Industrieanlagen AG. Humboldt Wedag. (I)
logan Corp. (4)
Monsanto Co.. (2. 3. 4)
National Filter Media Corp., (1)
National Mine Service Co., (4)
PeabodyABC. (1.3. 5)
Preiser/Mineco Div. Preiser Scientific Inc, (5)
Sly. W W.MIg. Co.(l)
SmicoCorp., (1)
Sprout Waldron, Koppers Co.. Inc. (I)
Trojan Oiv IMC Chemical Group. Inc.. (2. 3. 4)
West Virginia Bell Sales 4 Repairs Inc. (4)
Western Precipitation Div.. Joy Mlg Co. (I)
Wheelabrator-Frye Inc Air Pollution Control Div.
(I)
Wilson, R M.Co.(l)
Wire Cloth Enterprises, inc. (1)
BARGE-HANDLING
EQUIPMENT
Easlon Car 4 Construction Co
FMC Corp. Link-Bell Material Handling Interns
Div
Heyl 4 Patterson, Inc.
Kdnawha Mlg Co.
McDowell.WellmanF.ngri Co
McNally Pittsburg Mlg Corp
Webster Mlg Co
BARGE LINES
ALPS Wire Rope Corp
American Commercial Barge line Co
Armco Steel Corp.. Product Inlo.
Dravo Corp
Flowers Transportation. Inc.
M/G Transport Services. Inc
Midland Enterprises Inc.
Ohio Rivei Co. The
BARGES
American Commercial Barge lint Co
Beirut-hem Sleel Corp
Ora»o Corp
Mauthon Mlg Co
Uniled Stales SIM Corp
BASKETS, CLOTHES
Anuter Mine 4 Smelter Supply
Fairmont Supply Co
lyon Metal Prods Inc
Moore Co. I he
National Mine Service Co
BELT-LOADING STATIONS,
AUTOMATIC
Aggregates Equipment Inc
DEMAG Lauchhammer
Dowty Corp
FMC Corp. Ink Belt Material Handling Sysiems
Div
Fairfield Engineering Co
Hanson. R A. Disc. Lid
Huwood-lrwm Co
told Mtg Co. Inc
McOooell-Wellman Engrg Co
McNally Pmsburg Mlg Corp
Mmtec/iniernational. Div ol Barber Greene
fteinord Inc
Schroeder Bros Corp
Slamler. W. R. Corp. the
Webb. Jems B. Co
Webster Mlg Co
Wilson. R M Co
BELTS
1 CHAIN
2 FLAT TRANSMISSION
3 MINER'S LEATHER
4 V-Btl I
5 V-LINK
Acme Ham.lton Mlg Corp. Belling Di< , I?]
Adams Equipment Co.. Inc . 141
Baldwin Belling Inc. (2. 3 4}
Banner Bearings. (4)
Big Sandy Electric 4 Supply Co Inc (41
Bonded Scale 4 Machine Co. 11)
Boston Industrial Products Oiv Amer*ar Billnle
Inc. (2. 4)
Bowman Distribution. Barnes Group. Inc . 12 4)
Bridgeslone lire Co. Lie . (? 4j
Browning Mlg Div. Emerson Electric Co. 14 i)
CE Tyler Inc
Campbell Cham Co. (I)
Ceianese Fibers Marketing Co. (S)
Cincinnati Rubber Mlg Co. DI> ol Sieoart-
Warner Corp. (2)
Dayco Corp. Rubber Products Div. (2. 4 b)
Oicklnc.R J.(2. 4. 5)
Dodge Div. Reliance Electric Co (4. 5)
Duple. Mill 4 Mfg Co. (4)
Eaton Corp, World Headquarters. (4. 51
Eaton Corp. Industrial Drives Div. (4)
FMC Corp. Cham Div (1)
Fairmont Supply Co. (1.2 4 5)
Fenner. J H 4 Co. Lid. (I. 4 5)
Firestone Tire 4 Rubber Co (4)
Flenble Steel Lacing Co. (4)
Gates Rubber Co. The. (4)
Goodatl Rubber Co. (2. 4)
Goodrich. B F -Engineered Sysiems Cc. (2i
Goodyear Tire 4 Rubber Co (2 4)
Greengate Industrial Polymers ltd , (2 4)
Moll Rubber Co . A Randron Div (21
Huwood-lrwm Co
industrial Rubber Products Co. (1. 2 ' b)
Lee Supply Co Inc
liganCorp.(4)
Manneim Mlg 4 Belling. (2. 4. Sj
Mine Safety Appliances Co. (3)
National Mine Service Co (3)
Reinord Inc . (I)
Rosl. H 4 Co. (2)
Rubber Engineering 4 Mlg Co. (2)
Scandura. Inc. (2)
Shingle. L H.Co.. (2. 4)
Trelleborg Rubber Co Inc. (4)
Unilok Belling Co.. Div. ol Georgia Duck and Cord-
age Mill (2)
Uniroyal. Inc. (2. 4)
WebslerMlg.Co.il)
Wilson, f) M . Co . (4)
Wood's. T B. Sons Co.. (4. b)
695
-------
BIN GATES
Aggregates Equipment Inc.
Bonded Scale 4 Machine Co.
Card Corp.
Challenge-Cook Bros.. Inc.
Cleveland-Armstrong Corp.
Concrete Equipment Co. Inc.
Dorr Oliver Long, ltd
FMC Corp.. Link-Belt Material Handling Systems
Div
Fairlield Engineering Co.
Feeco International, Inc
Fuller Co.. A Gain Co.
Industrial Contracting ot Fairmont, tnc
Industrial Pneumatic Systems, Sub of industrial
Contracting ol Fairmont. Inc.
industrial Rubber Products Co.
Kanawna Mlg Co.
leman Machine Co
Lively Mlg 4 Equipment Co.
Marsh. E F . Engineering Co.
Menially Pittsourg Mlg Corp
Somerset Welding 4 Steel Inc
Standard Metal Mlg Co
Slephens-Adamson
Telsmnh Di.. Barber-Greene Co
Universal Road Machinery Co
Webster Mlg Co
Willis 4 Paul Corp. The
BIN-LEVEL INDICATORS
Automation Products, Inc
Big Noise Instruments. Oiv ol Improvecon Corp.
Bindicatcr Co . Div ot Improvecon Corp
Compton Electrical Equipment Corp
Concrete Equipment Co. Inc.
Delavan Electronics. Inc
FMC Corp. Material Handling Equipment Div
Fairfieirj Engineering Co
Ferro-TeJi. Inc
Fuller Co A Gal. Co.
Huwood-lrwm Co
Industrial Rubber Products Co
Jeffrey Mlg Div. Dresser Industries Inc
Kay Ray Inc
McNally Pillsburg Mlg Corp
Metntape Inc
'Micro Switch. A Div ol Honeywell
Mineral Services Inc
Monitor Mlg Co
Monilroi Mlg Co.
On.-uarl Corp
Ramsey Engineering. Co
Slephens-Adamson
Stevens. Inc, C W
Teins Nuclear
Unique Products Co
WESMAR Level Monitor Div.
BIN VIBRATORS
1 AIR OR GAS
Branlord Vibrator Co.. The. DIV ol Electro Me-
chanics. Inc
Carman Industries, Inc
Enei Magnetics
CMC Corp. Material Handling Equipment Div.
Firestone Tire 4 Rubber Co
Industrial Rubber Products Co
Long-Airdoi Co. A Div. ot the Marmon Group. Inc .
(1)
Preiser/Mmeco Div. Preiser Scientific Inc
Thayer Scale Hyer Industries. (I)
Vibcolnc.. (I)
Vibranetics. Inc
Wilson. R. M. Co.. (1)
BINS
1. CONCRETE-COAL STORAGE
2 BLENDING
3 REFUSE
4 PARTS STORAGE
ASV Engineering ltd. (I. 2. 1. 4)
Armco Sttf I Corp , Product tnlo
Asbmy Inoustrics. Inc. (3. 4)
Bethlehem Steel Corp. tl)
Bowman Distribution. Barnes Group. Inc . (4)
Concrete Equipment Co. Inc.
Fabricated Metals Industries. Inc
Fairmont Supply Co.. (4)
Feeco International. Inc.. (I. 2. 3)
Ferro-Tech. Inc.
First Colony Corp., (1)
Fnck-Gallagher Mlg Co.. The. (4)
Hammermills. Inc., Sub. ol Pettioone Corp. (2)
Holmes Bros. Inc.
I 4 M Equipment Sales, Inc.
Industrial Contracting of Fairmont, Inc, (1. 3)
Industrial Pneumatic Systems, Sub ol industrial
Contracting o| Fairmont. Inc.. (1)
Iowa Manufacturing Co, (1)
KanawhaMlg. Co, (2, 3)
Lively Mfg. 4 Equipment Co. (1. 2 J)
Lyon Metal Prods. Inc. (4)
MacDonald Engineering Co , (1, 2)
Manufacturers Equipment Co.. The
Marietta Concrete Co.. (1. 2. 3)
Marsh. E F., Engineering Co. (2)
McNally Pittsburg Mlg. Corp., (1, 2. 3)
Nell4Fry. Inc.. (I)
Preiser,'Mmeco Oiv.. Preiser Scientific Inc . (1. 2.
3.4)
Republic Steel Corp. (4)
Hipco. Inc.
Rutlmann Companies, {1. 2. 3)
St Regis Paper Co., (3. 4)
Sproul-Waldron. Koppers Co.. Inc.
Standard Metal Mlg. Co., (1)
Vibra-Screw Inc.. (2)
Willis 4 Paul Corp. The. (I 2. 3)
Wilson. R. M. Co.. (1. 3.4)
BLENDERS-COAL
FMC Corp., Link-Belt Material Handling Systems
Div.
Feeco International. Inc.
Gundlach. T. J.. Machine Co.. Div J M. J. Indus-
tries, Inc
Heyl 4 Patterson. Inc.
Jenkins ol Retlord Ltd
K-G Industries. Inc.
McDowell-Wellman Engrg Co.
McLanahan Corp.
Patterson-Kelley Co., Div. of Taylor Wharlon Co
- Harsco Corp
Preiser/Mmeco Div , Preiser Scientific Inc
Wilson. R. M. Co.
BLENDING &
PROPORTIONING
SYSTEMS-COAL
ASV Engineering Ltd
Duplei Mill 4 Mlg Co
FMC Corp. Link-Belt Material Handling Systems
Div
FMC Corp. Material Handling Equipment Div
Fairlield Engineering Co.
Feeco International. Inc
GEC Mechanical Handling Ltd
Hawker Siddeley Dynamics Engineer!^ Lid
Heyl 4 Patterson. Inc
Jenkins ot Retlord ltd
K-G Industries. Inc
Kaiser Engineers. Inc
Kanawha Mlg Co
K-Tron Corp
Lively Mlg. 4 Equipment Co
Marsh. E F . Engineering Co.
McDowell Wellman Engrg Co.
McNally Pittsburg Mlg Corp.
Mmtec/lnternational. Div. of Barber Greene
Patterson Kelley Co. Div. ol Taylor Wharlon Co
- Harsco Corp.
Ramsey Engineering. Co.
Thayer Scale Hyer Industries
BOX CAR LOADERS,
UNLOADERS
Bianfufd Viixalor Co. Ihe, [)iv ot tlt'ctro Me-
chjnti s Inc
Industrial Rubber Produrls Co
Mining f (iiniiment Ml|t Corp
MI Intfrnalionfll I lit
Vnroedrr Bros l>rp
BREAKERS
1 COAL ROTARY
2 LUMP. MINE
3. PICK-TYPE. PREPARATION
British Jeffrey Diamond. Div ol Dresser Europe
SA (UK Branch). (1.2. 3)
Card Corp. (I)
Daniels Company. The. (1)
Emaco Inc.
ferro Tech. Inc. (1,2)
GEC Mechanical Handling Ltd.. (1)
Gruenrjier Crusher 4 Pulverizer Co. (1)
Gundlach. T J. Machine Co. Oiv. J M J Indus-
tries, me
Hemscheidl America, (2)
Heyl 4 Patterscn. Inc.(l)
Jenkins of Retloro Ltd., (3)
Joy Mlg Co (U.K.) Ltd . (3)
KG Industries, inc.
Koppers Co. Inc. (1)
Koppers Co., Inc Metal Products Div, Hardmge
Operation. II)
I ively Mlg 4 Equipment Co. (1)
Long-Airdoi Co A Div of the Marmon Group. Inc .
(1.2)
McLdnanan Corp.. (I. 2)
McNally Pillsburg Mfg. Corp.. (1)
Mining Progress. Inc.. (1.2)
Mining Supplies. Ltd.. (2)
Owens Mlg. Inc. (1.2. 3)
Pennsylvania Crusher Corp.. (1.2)
Schroeder Bros. Corp.. (1)
Stamier. W R. Corp. The. (I. 2)
S!urtevantMil!Co.(l)
Wilson. R M.Co.d.2)
BUCKETS
1 AERIAL TRAMWAY
2 CLAMSHELL
3 DRAGLINE
4. DRAGLINE ARCHES, CHAINS
b ELEVATOR
6. TRACTOR AND WHEEL-LOADER
Aggregates Equipment Inc.. (5)
Alln-Chalmers. (6)
American Poclain Corp. (2)
Asbury Industries. Inc., (5, 6)
BalrJerson Inc.. (6)
8ucyrus-ErieCo.(4)
BJCW Co., Plsstic Products Oiv.. Polychem Pro-
ducts, (5)
Card Corp
Caterpillar Tractor Co. (6)
Concrete Equipment Co. Inc.. (5)
Duplei Mill 4 Mlg Co. (5)
Elkhorn Industrial Products Corp.. (6)
ESCO Corp.. (2. 3. 4. 5)
FMC Corp, Material Handling Equipment Div.. (5)
Fairiiek) Engineering Co. (5)
Fairmont Supply Co., (5)
Ferro-Tech. Inc
Fiat-Allis Construction Machinery. Inc. (6)
Haulnuslers. Inc,, (3)
Hendrn Mlg Co, Inc.. (3)
Industrial Rubber Products Co. (5)
Interstate Equipment Corp. (1)
Jeffrey Mfg. Div. Dresser Industries Inc. (5)
KHD Industreanlagen AG. Humboidt Wedag
Kanawha Mfg. Co.. (5)
LaubensteinMlg. Co.. (5)
Manor, Power Shovel Co Inc. (3. 4)
McNally Pittsburg Mlg Corp. (5)
Ore Reclamation Co. (5)
Owen Bucket Co.. The. (2)
Page Engrg Co.. (3)
Pembone Corp. (2. 3)
Philippi-Hagenbuch Inc. Ltd. (6)
Rennord Inc. (5)
S 4 S Machinery Sales. Inc.. (6)
Standaro Metal Mlg Co (5)
Stephens-Adamson (5) .
Terei Div . CMC. (6)
Uni Tool Attachments, Inc.. (6)
Webster Mlg Co.. (5)
Wilmol Engineering Co. (5)
Wilson. N M Co. (I. 51
Workman Developments, Inc , (1. 5)
Vaun Williams Bucket Co.. (2. 3. 4)
Young Corp. (61
CAR DUMPERS, MINE
Anas R.nlioaO Construction Co
Card Corp
Clinwllsvllh! Corp
Dorr OIIVPI long, ltd
IMC Corp link [tell Material Handling Systems
(J,v
Heyl 4 Pallrrson. Inc
Kanjwha Mlg CD
McNjIly Pillsburi Mtg Corp
Mining Equipment Mlg Corp
Nolan Co. The
Rubrrls 4 Scnjeler Co
696
-------
CAR DUMPERS, R.R.
ROTARY
Aggregates Equipment Inc.
Atlas Railroad Construction Co.
Dilco. Inc.
Dorr Oliver Long, Lid.
FMC Corp.. Link-Bell Material Handling Systems
Div.
Heyl 4 Patterson, Inc.
McOowell-Wellman Engrg. Co.
Mining Equipment Mlg. Corp.
National Air Vibrator Co.
Whiting Corp.
CAR HAULS, MOVERS,
PULLERS, R.R.
Aldon Company. The
Atlantic Track I Turnout Co.
CE-Ehrsam
Coeur d'Alenes Co.
Dorr Oliver Long, Ltd.
FMC Corp. Link-Belt Material Handling Systems
Oiv.
Fairmont Supply Co.
Heyl S Patterson, inc.
ISCO Mfg. Co.
- Marmon Transmotive Div., Sanford Day Products
McDowell-Wellman Engrg Co.
McNally Pittsburg Mlg. Corp.
Nolan Co.. The
Pettibone Corp.. Pettibone New York Div.
Roberts 4 Schaeler Co.
Stamler. W. R.. Corp., The
Stephens-Adamson
Whiting Corp.
CAR HOLDERS. STOPS,
MINE
Abei Corp.. Railroad Products Group
Aldon Company, The
Card Corp.
Connellsville Corp.
Dorr Oliver Long. Ltd.
Duquesne Mint Supply Co
Huwood-lrwin Co.
Kanawha Mfg Co.
Marmon Transmotive Div.. Sanlord Day Products
Midwest Steel Div.. Midwest Corp.
Nolan Co.. The
CAR-LOADING STATIONS.
AUTOMATIC-MINE-CAR
Card Corp.
Dorr Oliver Long. Ltd
Kaiser Engineers. Inc.
Marmon .Transmotive Div.. Sanlord Day Products
Nolan Co., The
Schroeder Bros. Corp.
Stamler. W R.. Corp. The
Wilson. R. M., Co.
CAR-LOADING STATIONS,
AUTOMATIC-R.R.-CAR
Dorr Oliver Long, Ltd
FMC Corp.. Link-Bell Material Handling Systems
Oiv.
Fairteld Engineering Co.
General Electric Co. Transportation Systems
. Business Div
Htyl & Patterson. Inc
Kaiser Engineers. Inc
Marmon Transmotive Oiv. Sintord Day Products
McOoweU-Wellman Engrg Co.
McNally Pittjburg Mlg Corp.
Mmtec'International. Div of Barber-Greene
Nolan Co. The
Schroeder Bros. Corp.
Stamler. W R. Corp.. The
Webster Mlg. Co.
Whiting Corp.
CAR MOVERS, R.R.
A I K Railroad Materials, Inc
Advance Car Mom Co Inc.
Aldon Company, The
Anuter Wine 4 Smeller Supply
Allanl.c Track I Turnout Co.
Clark Equipment Co.. Construction Machinery
Oiv
Coeur d'Alenes Co
Dorr Otner Long, ltd
Fairmont Supply Co
General Scientific Equipment Co
ISCO Mlg. Co.
Marmon Transmotive OH . Sanlord Day Products
McDowell-Wellman Engrg. Co
Midvnt Steel Oiv. Midwest Carp.
Nolan Co.. The
Pettibone Corp. Peltibone New York Oiv.
Sanlord-Day/Marmon Transmotive. Oiv. ol the
Marmon Group, Inc
Stamter. W R, Ccxp, The
Stephens-Adamson
Waiai Industries Ltd
Whiting Corp.
CAR RETARDERS, MINE-CAR
Abei Corp. Railroad Products Group
Aldon Company. Th«
Oorf Oliver Long. Ltd
Ouquesne Mm Supply Co
FMC Corp.. Link Belt Material Handling Systems
On.
Fairmont Supply Co
Jenkins ol Reltord Ltd
Kanawha Mlg. Co
Marmon Transmotive Div.. Sanlord Day Products
Sanlord-Day/Marmon Iransmotive. Oiv ol the
Marmon Group. Inc.
CAR RETARDERS, R.R. CAR
Aoei Corp. Railroad Products Group
Aldon Company. The
Atlas Railroad Construction Co.
Duquesne Mine Supply Co.
FMC Corp.. Link-Bell Matenal Handling Systems
Oiv
Heyl & Patterson. Inc.
Kanawha Mlg. Co.
Logan Corp.
Marmon Transmotive Div. Sanlord Day Products
McDowell-Wellman Engrg Co.
McNally Pirtsburg Mlg Corp
WABCO Union Switch 4 Signal Div. Westing-
house Air Brake Co.. an American-Standard
Co.
CAR SHAKERS, R.R.
Aldon Company, The
Allis Chalmers
Allis-Chalmers. Crushing 4 Screening Equipment
Brantord Vibrator Co, The, Div ol Electro Me-
chanics. Inc.
Industrial Rubber Products Co.
Logan Corp.
National Air Vibrator Co.
Vibcolnc.
CAR SPOTTERS, MOVERS,
MINE
Aldon Company. The
FMC Corp. Material Handling Equipment Oiv.
ISCO Mlg Co
Kanawha Mlg Co.
Marmon Transmolive Oiv. Sanlord Day Products
Morgentown Machine 4 Hydraulics. Inc.. Div
Nail. Mint Service Co.
Nolan Co. The
Scnroeder Bros Cnrp
Slamlet, W. R, Corp. Ihe
CHUTES
I DIVERSION. COAL-LOADING
2 TELESCOPING. COAL LOADING
ASV Engineering Ltd. (I)
Bethlehem SleeJCorp, (1)
Cleveland-Armstrong Corp. (1)
Concrete Equipment Co.. Inc
FMC Corp. Link-Sell Matenal Handing Systems
Div, (1.2)
FairMd Engineering Co
Holmes Bros me.. (2)
Industrial Contracting ot Fairmont. Inc.. (1)
Kanawha Mlg. Co. (I 2)
LauDensten Mlg Co
Lively Mil 4 Equipment Co, (I. 2)
McNaily Pittsburg Mlg. Corp. (1.2)
Savage. W J. Co.. (1)
Somerset Welding 4 Steel Inc. (I)
Stomler.W.R.. Corp.. The. (1)
Trcneborg Rubber Co.. Inc, (1.2)
United McGill Corp.
Wet*. tervisB, Co, (1.2).
Webster Mlg. Co.. (1.2)
Willis & Paul Corp.. The
Wibon. R. M. Co, (1.2)
Workman Developments, Inc.
CLARIFIERS
Crane Co
Dorr-Oliver Inc.
Don driver Lone, Ltd.
Enviru, Inc.
Errnro-Clur. • OK. ot Amur Corp.
Enwonmenlal Equip On, FMC Corp.
Ermrotxh Corp, Emo 8SP On
Heyl & Pittenon. Inc.
Joy Mlg Co, Denw Equipment On.
KHD Mintrietntigen AC. Humbotdt Wedag
Koppars Co, Inc
Park son Corp.
Redding Co, Jones A.
Remord Inc.
Sala International
LMtnoc Limited
CLASSIFIERS
1. AIR
2. HYDRAULIC
3. MECHANICAL
Aerofel Mils Ltd, (1)
C-E Ravmond/Baroert Snow. On Combustion
Engineering. Inc, (1. 3)
CE Tyfer Inc, (3)
Daniels Company. The, (3)
Oeister Concentrator Co. Inc, The, (2)
DorrOiW inc., (2)
Dorr Oner long, IM, (2. 3)
G«nenJ Roource Corp.
GruendUr Crusher 4 Purmwr Co, (1)
Heyl t Ptroncn. Inc, (2)
Joy Mfg. Co, DerMr Equipment On.
KHD Indintnetnlafin AG. HumWdl Wedaf, (1.
Kennedy Van Saw Corp Sub. ol McNady pins-
burg. (1)
Kretrs EnfinMn, (2)
Unatei Corp ol Amend, (2)
MaujcOiY.DorujIdlonCo.ll)
Mdanahan Corp., (2)
McNaty Pimtwt Mlg. Corp.. (3)
Rnnord Inc.. (3)
Sala International. (1,2. 3)
SturtewntMiCo,(l. 3)
Telsmitti On, BarberXiraena Co, (3)
Unite Limned
UrwenM Road Machinery Co, (1)
WEMCO Or>, Emvotach Corp, (2)
Wilbams Patent Crush* t Put*. Co, (I)
Wilmot Engineering Co, (3)
Wilson. R. M, Co, (3)
CLEANERS, AIR. FOR COAL
(SEE TABLES. MR)
697
-------
COAL-ANALYSIS
LABORATORIES
Commercial Testhg * Engmemg Co.
fisher Scientific Co.
Ham Research, he.
Prerser/Mmeco By.. PraJtir Saentrie he
(MbcUnted
COAL BREAKERS. C02. AIR
Eagt« Crusher Co. he.
lontAinku Co. A Oiv. ol the Marmon Group, inc
COAL INSPECTION.
SAMPLING
Commercial Testing t Eflgneerng Co.
Holmes Bra. he.
Kaaa Engineers, tx.
UHhan. Abe w., Entmaring Ca
Meftaoy HHsburi MJf, Corp.
Mr. Paul Co.. he.
COAL STORAGE
(SEE STOtUGf A RECUUMING
SYSTEMS)
COMMUNICATORS.
INTEROFFICE & PLANT
• CS£ Mnr Stnicc Co.
Cotes Rtdb
Canaunatau t Control En* Co. LM.
D>«. John* SOB (Derby) HI
Fam Or,. Gorton hduflnes. he.
G*-Times Corp
Moo, he.
3*1 Co
l»iw Safety Apptancet Co
MaMb Conmnaiiia t Etatrano
S0MMOV Bras Conx
Stromberg-Carlson Corp.
•Stan. H M.. Co
CONTROLS
1 CABLE-TYPE
2. INDUCTIVE -CARRIER REMOTE
3. LKJUID-lEVEl
4 SOLIDS LEVEL
5 STATIC
6 REMOTE. AUTOMATIC. R R
7 CONVEYOR •
Aeco. Brett* On.. (3)
too. Cable Controls On.. (1)
Acco. Integrated Handling Systems Do. (7)
AHen'BrarJleyCo.<3)
Mis-Cnalms. (5)
Akior Instrument Co.
Automaton Produce, he.. (3. 4)
Babccck & Wfcoi. (3)
Big Nose Instruments, Ore. of tnprovecon Corp..
(4)
Bndicator Co.. Dr>. of hiproveeon Corp., (3, 4)
Coftns Radio. (6)
Communcahon& Control Eng Co. ltd (3 5 7)
Compton Electrical Equipment Corp., (1. 3 4 7)
Continental Conveyor t Equipment Co. (7)
Control Produces, he.. (1. 7)
Controlled Systems Inc.. (5, 7)
Conveyor Components Co.. (1. 7)
CrDuse-HindsCo.(7)
Cutler Hammer. Inc.. (4. 5. 6. 7)
bdavan Electronic*, he. (3. 4)
Diversified Electron*!, he.
Eaton Corp.. Industrial Drives On. (7)
talon Corp. Trinsmuion On
Electric Machinery Mtg Co. (3)
FMC Corp .Material Handling Iquipmeni Di.. (4)
rairtield Engineering Co. (6. 7)
Femco l»v, Gulton Industries, tnc. (? 6)
Fisher Controls Co (3 4)
Fo.bo.oCo. Ihe. (3)
Fuller Co.. A Gain Co.. (4)
GTE Sylvania he.. (5. 7)
General Electric Co. hduslrial Sales F>v. (3 5
7)
General Electric Co. Transportation Systems
Business On, (6)
General Equpment » Mtg Co. Inc.. (6 7)
General Resource Corp. (7)
Gnnrte.-CWI Distributing Co., (3)
Mav*« Siddetey Dynamics Engmwim, lid
( 6. 7)
Honeywell he.. Process Control Ov. (3)
Humod-lnm Co. (7)
Huwood Limited. (6. 7)
Jabto. he. (6. 7)
Jeffrey Mining Machinery On. Uressei Iraluslnel
Inc (7)
joy Mtg Co. Denver Equipment Ov 13)
Kay Ray Inc. (3. 4)
Leeds t Northrap Co. (3)
Lours »to On. Unon Industrial Products. Inc. (J)
Metntape he.. (3. 4)
Micro Switch. A On ol HoneyMll. (3. 4. 7)
Mineral Stnices he.
Monitor Mfg. Co, (4)
Morse Controls OH. Rockwell Intl
Motorola Commureutjons t Electro/ws (61
National Electric Col Dw ol McGrj» Edisor. Co.
(3.61
OhmartCorp.(3. 4)
Pace Transducer Co. On of C J Enterpnus. (3)
Pheips Dodge Industries, Inc. (I)
Preiser/Mineco ftv, Pmser Scicntjlic Inc. (3. 4.
7)
Reimce Electric Co, (5)
Revere Corp ol America. Sub ol Neptune Intl
Corp. (3)
Robcon Corp.. (S)
Square 0 Co., (3)
Stevens he.. C W
Taylor Instrument Process Control Div Sytaron
Corp. (3)
Tuas Nuclear (3. 4)
Unique Products Co. (3. 4. 7)
WABCO Unon Switch I Signal Ov. Westing
house Air Brake Co.. an American Standard
Co.(6)
Weamemead Co. The. (I)
Wrtb. Jervn B. Co.. (7)
vVCSM/U)level Monitor On. (3 4)
West Virginia Armature Co. (7)
Westinghouse Electric Corp. (3. b 6)
Wichita Clutch Co. Inc
CONVEYING SYSTEMS
1. HYDRAULIC
2. PNEUMATIC
Cable Bert Conveyors he.
DP Way Corp.. (2)
DuconCo. he. The. (2)
fSCO Corp. (2)
Ferro-Tech. me.. (2)
Fuller Co.. A GiU Co. (2)
GEC Mechanctl HMdhng Ltd.. (2)
General Resource Corp.. (2)
Hammermillv he. Sub rt Petbbone Corp. (1.2)
Hanson. R A.. Disc, Itu
hdusthal Contracting ol Fwmont. he. (2)
hdustnal Pneumatic Systems. Sub of Industrial
ContracMf ol Fairmont he.. (2)
tnoustnal Rubber Products Co,
KHD Industneanlagen AG. Hunboldt Wotag. (1.
Kennedy Van Saun Corp. Sub. ol McNaty Prthv
burg.(2)
Lake Shore, he.
Logan Corp
Long-Alrdn Co A On <* the Marmon Group, he..
(1.2)
Macawber Engneenng ltd. (2)
Manufacturers Equpment Co.. Ihe. (2)
Mmng Eqopmnt Mfg Corp., (I. 2)
NFE International LM. (2)
fttta Manulacturmj. (2)
RennortJhc.
Ripco.lnc (2)
Sprout W«Wron. Koppen Co. he. (2).
IrMtfwtUCorp.d.?)
West Virginia Armilurr To. (I)
CONVEYOR BELT PARTS.
SERVICES
1 CLAMPS
3 CLEATS
4. COLO VULCANIZING
5 CUTTERS
6 DRIVE PULLEYS
7. FASTENERS. SPLICING
MATERIALS
8 IDlERPUUEYS
9 LOADING STAlrONS. MINE.
AUTOMATIC
10 REPAIR KITS
11 REPAIR MATCRIM
12. REPAIR SERVICE
1 3 SPLICING, SHOP ft FIELD
14. TIGHTENERS
15 TRIPPtHS
16 VULCANI7ERS
17. WINDERS
18 CONTROL SWITCHES
Aggregates Fompment he, (7 8)
Anderson Manor (USA) ltd. (8)
Armstrong, Bray tCo.(7)
Automatic VuKanim Corp. (3. 4. 7. 10. 11.
12. 13. 16)
Baldwin Belting Me. (2. 4,6, 7.8, 12. 13, 14)
Banner Bearings. (6, 8)
Barter-Greene Co., (2. 6. 8. IS)
Bekaert Steel Wire Corp
Big Sandy Ekxtnc A Supply Co. Inc.. (6. 7)
Bonded Scale 1 Machm Co (2. S. 7. 8)
Browning Mtg. Or.. Emerson Electric Co., (6. B)
CE-Cmam. (8. 15)
CSEMme Service Co. (7. 8. 10. 13)
Cheatham UK Swrtchmg Device Co. (18)
Cincinnati Rubber Mtg Co. Drr ol Snuart-
Warner Corp. (3. 10. ID .
Coeurd-Alene>Co.(17)
Compun Ekxmcal Equpment Corp. (18)
Concrete Eoucmenl Co. Inc. (6. 8. 15. 18)
Contmntal Conveyor t Equipment Co. (2.6. 8.
15)
Control Products, he. (18)
Conveyor Components Co. (2. 18)
Cnxne-HmdsCo.(18)
OKI he. R J. (6. 8)
Dodge Or,. Retance Electric Co. (6. 8)
DowtyCorp.(2. 6. 8. 9)
Dupto tM t Mfc Co. (6 8)
Eaton Corp. hdustnal Ones Div. (6. 8)
ELMAC Corp.. (2. S. 6. 7. 8, 18)
FMC Corp. Material Handkng Equpment On. (6,
8.15)
Fatnr Bearing DM. ol Tetran he.. (8)
Fairmont Suppy Co. (6. 7. 8, 14)
Fastener House, he.. (7)
Fenwr Amenca LM.. (2. 5. 7)
Fenner. J H. » Co. ltd. (2, 5, 7. 13)
Fem>Tech. Inc.. (2)
Ftonbfe SteeUaong Co. (1. 2. 3. S. 7.11,14)
Flood City Brass t Electric Co.. (12)
GEC Mechanical Handing LM.. (6. 8. 15)
General Electric Co. hdustnal Sales On. (18)
General Equvment t Mtg Co.. he, (18)
General Spto Corp.. (1. 5. 7.10,11.16)
Goodman Equpment Corp.. (6. 8)
Goodnch. B F Engineered System Co. (4. 7.
11.13.16)
Goodyear Tire t Rubber Co. (7. 12. 13)
Greengite Indus no Pohrntrs Ltd. (13)
rjuyan Machnery Co, (4. 8)
Hammerm**. he.. Sub ol Pendent Corp. (8)
HaydavhMm Conttou Ltd. (2. 7)
Henti Manutadunn. he.. (12. 13. 16)
Hewitt Rotats Conveyor Equpment On. Litton
Systems, he. (2)
Hob Rubber Co. A Randron On. (3. 4. 6.- 7)
HuwroHrwm Co. (2. 6. 8. 15)
Huwood limited. (8)
hdusthal Rubber Products Co.. (1.3.4.5.6, 7.
8 10. 11. 12. 13. 14. 16)
Iowa Manufacture* Co. (o. 7. 8)
Jabco. he. (18)
Jeffrey Mtg Dur.. DreuarhdusMeshc.il. 2.6.
8.14.15)
Kennedy Metal Product! t Bukanp. he.. Jack.
(18)
KotborgMlg Corp. (2.6, 8)
IftSupplyU.lrK.IZ. 10. II)
ItmenMatlwnt Co.(6, 12)
llMIn Corp ol Amtrirj, (?, 11)
lagan Corp, (I M. 16)
l4nfA»dD»Co ADM ol Ota Marmon Oroup.M .
(7.8.9. 12. 13. 17)
MamonServices,he..(1.3.4.5.6.7.8.10. H.
12. 13. 16, 17)
Marsh. E F. ErujjnamngCo. (6. 8)
Marnn Engrg Co.. (2. 14)
Material Control, he, (2)
MATO. 17)
698
-------
McNally Pittsburg Mfg. Corp. (6. 9. IS)
Micro Switch. A Div ol Honeywell. (18)
Mineral Services Inc.. (2)
Molded Dimensions Inc.. (2)
National Mine Service Co.. (7)
Owens Mfg., Inc.. (6. 8. 14. 18)
Poly-Hi. Inc.. (8)
Portec, Inc.. Pioneer Oiv.. (2. 6. 8, 14. IS)
Preiser/Mineco Oiv, Preiser Scientific Inc.. (2)
Rema-Tech. (1.3, 4. 10. 11. 12. 13)
Rennord Inc.. (2. 6. 8. 9. 14. IS)
Reinord Inc., Process Machinery Div.. (6. 8)
Rock Industries Machinery Corp. (2, 6)
Schaeler Brush Mfg. Co.. (2)
Shaw-Alme. Industries Ltd.. (1.16)
Shingle. L.H, Co. (1.7. 10. 11. 13)
Stephens Adamion. (2. 6. 8, IS)
Templeton. Kenly 1 Co.. (14)
Umlok Belting Co., Div. ol Georgia Ouch and Cord-
age Mill. (7)
United States Steel Corp.
Van Gorp Mlg. Inc.. (6. 8)
Vulcan Materials Co.. Southeast Div., (12. 13.
16. 17)
Waiai Industries Ltd.. (1.5. 7)
Wallacetown Engineering Co. Ltd. (18)
Webb. Jenis 6. Co. (6. 8. 9. 14. IS. 18)
Webster Mlg. Co.. (8. 9)
West Virginia Armature Co. (6. 8. 11. 12, 18)
West Virginia Belt Sales & Repairs Inc.. (1, 2. S.
6.7.8. 10. 11. 12. 13. 14. 16)
Willis A Paul Corp.. The. (15)
Wilson. R. M.Co.(1.2. 3.-6. 7. 8. 9)
Workman Developments, Inc.. (2. 8)
CONVEYOR BELTING
Acme-Hamilton Mfg. Corp.. Belting Div
Aggregates Equipment Inc.
Baldwin Belting Inc.
Banks-Miller Supply Co '
Bonded Scale & Machine Co.
Boston Industrial Products Div.. American Biltrite
Inc.
CE Tyler Inc
Celanese fibers Marketing Co
Cincinnati Rubber Mlg Co. Div. ol Stewart-
Warner Corp.
Concrete Equipment Co. Inc.
Dick Inc.. R. J.
Dowty Corp
Duple! Mill & Mlg. Co.
Eaton Corp.. Industrial Drives Div.
ELMAC Corp.
Fairmont Supply Co.
Fenner America ltd.
Fenner. J. H. & Co.. Ltd.
Ferro-Tech. Inc.
Fleiowall Corp.
Goodall Rubber Co
Goodncn. B. f -Engineered Systems Co
Goodyear Tire & Rubber Co
Greengate Industrial Polymers Ltd.
Hoi; Rubber Co.. A Randron Div
Huwood-lrwin Co.
Industrial Rubber Products Co.
Iowa Manufacturing Co.
Lee Supply Co.. Inc.
Logan Corp.
Long-Airdoi Co A Div. ol the Marmon Group, Inc.
Manson Services. Inc.
Mineral Services Inc
National Mine Service Co.
Rost. H & Co.
Rubber Engineering & Mlg Co.
Scandura, Inc.
TBA Industrial Products Ltd.
Trelleborg Rubber Co.. Inc.
Unite* Belting Co.. Div. of Georgia Duck and Cord-
age Mill
Umroyal. Inc.
United States Steel Corp.
Vulcan Materials Co.. Southeast Div.
Waiai Industries Ltd
West Virginia Bell Sales & Repairs Inc.
Wilson. R M., Co
CONVEYOR COVERS
Aggregates Equipment Inc
Armco Steel Corp.. Product Into.
Automatic Vulcanners Corp.
Baldwin Belting Inc.
Barber-Greene Co.
Bended Scale & Machine Co.
Continental Conveyor & Equipment Co.
Iowa Manulactunng LO.
Jeffrey Mlg Div., Dresser Industries Inc.
Kanawha Mlg Co
Kolborg Mlg Corp
Lee Supply Co.. Inc.
linatex Corp. ol America
Long-Airdoi Co. A Div. ol the Marmon Group, Inc.
Marsh, E. F.. Engineering Co.
Portec. Inc.. Pioneer Div.
Raychem Corp.
Reinord Inc.. Process Machinery Oiv.
Rock Industries Machinery Corp.
Trelleborg Rubber Co.. Inc.
Webb. Jems 8. Co.
Webster Mlg. Co.
Wilson. R. M Co.
CONVEYOR GALLERIES,
TUBULAR
Aggregates Equipment Inc.
Continental Conveyor & Equipment Co
Fairfield Engineering Co
Industrial Contracting of Fairmoni. Inc
Industrial Steel Co
Kanawha Mfg. Co .
Lee Supply Co.. Inc.
Lively Mfg. & Equipment Co.
Marsh. E. F . Engineering Co.
McNally Pittsburg Mlg. Corp.
Portec. Inc.. Pioneer Div.
Rock Industries Machinery Corp.
Webb. Jervis B.. Co
Wilson. R M. Co
CONVEYOR-PULLEY
LAGGING
Aggregates Equipment Inc.
Automatic Vulcamrers Corp.
Baldwin Belting Inc
Bonded Scale & Machine Co.
Cincinnati Rubber Mlg. Co.. Div of Stewart
Warner Corp.
Concrete Equipment Co.. Inc.
Dick Inc.. R. J.
Dowty Corp
Dure> Products. Inc. Nail Wire Cloth Oiv.
FMC Corp.. Material Handling Equipment Div
Fairmoni Supply Co.
General Splice Corp.
Goodall Rubber Co.
Goodrich. B F.-Engineered Systems Co
Goodyear Tire & Rubber Co.
Heintr Manufacturers, Inc.
Holt Rubber Co., A Randron Div.
Industrial Rubber Products Co
lee Supply Co.. Inc.
Leman Machine Co.
Linatex Corp. ot America
Manson Services. Inc.
Marsh. E F , Engineering Co.
Rema-Tecn
Rubber Engineering & Mlg Co.
Scandura. Inc.
Van Gorp Mfg Inc.
Vulcan Materials Co. Southeast Div
West Virginia Belt Sales & Repairs Inc.
Wilson, R M. Co.
CONVEYOR SKIRT BOARD
Acme-Hamilton Mlg. Corp. Belting Div
Aggregates Equipment Inc.
Automatic Vulcanuers Corp.
Bonded Scale & Machine Co
Boston industrial Products Div. American Biliriie
Inc
CF.-Ehisam
Cincinnati Rubber Mlg Co. Div ol Stewart
Warner Corp
Concrete I qtuptnent Co. Inc
Continental Conveyor & Equipmrnl Co
Conveyor Comixinents Co
Ourei Products. Inc.. Nail Wire Cloth Iliv
fairmonl Supply Co
C.EC Mediumal Handling I Id
Goodrich. R I tngmecred Systems Co
Goodyear I ire & Rubber Co.
Hammermills. Inc.. Sub ol Pettibone Corp
Holi Rubber Co. A Randron Div
Industrial Rubber Products Co.
Iowa Manufacturing Co.
Kanawha Mlg Co
Kolborg Mlg Corp.
Lee Supply Co, Inc
linalex Corp of America
Manson Services. Inc
Marsh. E F. Engineering Co
Portec. Inc.. Pioneer Div.
Schaefer Brush Mfg Co
Trelleborg Rubber Co.. Inc
Webster Mtg Co
West Virginia Bell Sales & Repairs me
Wilson R M . Co
Workman Developments, Inc
CONVEYOR WEIGHERS
Aggregates Equipment Inc
ASEA me
Auto Weigh Inc.
Cardinal Scale Mfg Co
Fairbanks Weighing Div., Colt industries
F airfield Engineering Co
Howe Richardson Scale Co
Inllo Resometnc Scale Inc
Jellrey Mlg Div. Dresser industries inc.
KHO Industrieanlagen AG. Humboldt Wedag
Kay-Ray Inc
Kilo-Wale Inc.
K Iron Corp
Lively Mlg & Equipment Co.
Ohmart Corp.
Ramsey Engineering. Co.
Revere Corp. ol America. Suo ol Neptune mil
Corp
Reinord Inc.
Reinord Inc. Process Machinery On
Teias Nuclear
Thayer Scale Hyer Industries
Thurman Scale Co Div. Thurman Mlg Co
Webb. Jer/is B.. Co
Wilson R M . Co.
CONVEYORS
1 APRON
2 ARMORED LONGWALL
3 BELT
4 BELT, EXTENSIBLE
5 BEIT-FEEDING
6 BUCKET
7 BUCKET-WHEEL
8 CABLE-BELT
9. CHAIN & CHAIN & FtlGHT
10 DECLINE
11. DEWATEWNG
12 ELEVATING
13 ELEVA1ING. MINE 1RANSFER
CAR LOADING
14. MINE BRIDGE
15 MINE. FLEXIBLE CHAIN
16. CHAIN. MOBILE-HEAD
17 PORTABLE
18 ROPE & BUTTON
19. SCREW
20. SECTIONAL
21 SHAKING. VIBRATING
22 SPIRAL LOWERING
23 STOCKPILING & RECOVERY
ASV Engineenng Ltd . (3. 5:9. 23)
Acco, Integrated Handling Systems Div. (3)
Acco Mining Sales Div. (2 6. 7. 9)
Acco. Unit Conveyor Div. (3. 5. 17)
Aggregates Equipment Inc. (3.6.9.17.19. 21.
23)
Alpine Equipment Corp.. (2. 3. 9)
American Alloy Steel. Inc.
Anchor Conveyors Div. Standard Alliance Indus.
Inc.. (I. 3.6.9. 12)
Anderson Mtvor (USA) ltd. (2. 3. 4)
A-f-0 Inc
Auto Weigh Inc . (}. 5)
Barber Greene to. (3 Hi. U. ». I'a.'f'i)
Bonded ScaK & Machine Co (I 3. V 9. 12)
British Jeffrey Diamond Oiv ol f>f*stri Europe
SA (UK Brawn) (2 9 I J. 13 I')
Cl Ihrum. (J. 5 8 9. 10 12. 2JI
CMICorp.U 9. 12)
Cable Bell Conmvors me, (j. 8)
Campbell Cham Co. (9)
Canlon Stoker Corp (19. 21)
Card Corp. (3. 4. 8).
Carman Industries. Inc . (I I 21)
Certified Welding Services Inc
Cincinnati Mine Machinery Co. 19)
699
-------
Cincinnati KuDDer Mlg Lo. Uiv. ot Stewart-
Warner Corp.. (3. 4. 12)
Concrete Equipment Co. Inc . (3. 12, 17. 19)
Connelisvrlte Corp. (1.6. 9. 11.21)
Continental Conveyor 4 Equipment Co.. (3. 5. 7.
10. 13. 17.20,23)
Crown Iron Works Co. (19)
Daniels Company, The. (9)
Dayton Automat* Stoker Co. (19)
OEMAG Lauchhammer. (3. 5)
OeronR&DCo.. Inc. (19)
DoscoCorp.<4. 14)
DowtyCorp.(2, 3 4. 5.9. !4)
Draw Corp. (6. 7. 14. 18,23)
Duple. Mill A Mlg Co.. (3. 6. 19)
Eicknorl America Corp. (2. 9)
UMAC Corp. (3 20)
Enterprise Fabricators. Inc. (6)
EMU Magnetics. (1. 3. 5. 12. 17. 21)
ESCO Corp. (9)
FMC Corp. Link-Bell Material Handling Systems
Oiv.0.3. 9. 10. 12. 14.23)
FMC Corp, Material Handling Equipment Div..
(12. 19.21)
Fairchild. Inc.. (3)
FairMd Engineering Co.. (1.3.4,5.6.9,10.11.
12. 17, 19.23)
Fairmont Supply Co. (6. 9, 12. 13. IS, 19)
Fate-International Ceramic & Processing Equip-
ment. Div. ol the Fate-Root-Heath Co.. a Ban-
ner Co. (3)
Feeco International. Inc.. (3. 9. 10 12. 17. 19.
23)
Fenner. j. H. 1 Co. Ltd. (3)
Ferro-Tech. Inc. (3. 6. 12. 17)
FleKher Sutcl.fle Wild. Lid . (3)
Fuller Co, A Can Co. (9)
UEC Mechanical Handling Ltd.. (1. 3. 19. 21)
General Kinematics Corp .(21)
General Resource Corp. < 19. 21)
Goodman Equipment Com.. (3. 4. 21)
Grinde«-CWI Dislnbutmg Co. (11)
Gruendlet Crusher 4 Puiventer Co, (3. 12)
Hammermills. Inc.. SuD ol PettiDone Corp.. (3.
17.23)
Hanson. R.A., Due , lid
Head Wrightson 4 Co Ltd.. (23)
Hemsche-dt America. (2)
Heroic) Mlg Co. (1.2, 9, IS. 17,21.22)
Hewrrt-Robns Conveyor Equipment Div. Litton
Systems Inc. (3 4, B)
Heyl 4 Patterson. Inc. (7. 23)
Holmes Bios Inc. (3. 6. 22)
HuMXXHrwm Co.. (2. 3. 4. 5. 9, 13. 15)
Huwood Limned (2. 3. 4)
Industrial Contracting of Fairmont. Inc.. (1. 3, 5,
6.9. 12. 19.20.21.22.23)
Industrial Rubber Products Co. (1.3.5.6.9.10.
12. 17.19.20)
Iowa Manufacturing Co. (3. 13. 17 23)
Irvin.McKetvy Co., "he. (3. 9. 21. 22. 23)
janes Manufacturing Inc.. (1. 9. 11. 12)
Jeffrey Mfg. Dn. Dresser Industries Inc.. (1.3,4.
5.6. 7. 12. 17. 19.20.21.22,23)
Jeffrey Mining Machinery Div, Dresser Industries
inc. (9. 14. 15. 16, 17)
Jenkins of Rerford Ltd., (3. 9. 23)
Joy Mfg Co.. (2, 4. 14)
Joy Mlg Co (U.K.) ltd.. (4. 14)
KHD Industneanlagen Ati. Humboldt Wedag. (3.
6. 19.21)
Kaiser Engineers. Inc., (23)
KanaxhaMfg Co.. (1. 3. 4, 6, 9, 12. 18)
Koiborg Mle Corp. (3. 5. 23)
Lee-Norse Co. Sub of Ingersoil-Rand Co.. (14)
lee Supply Co. Inc. CJ. 11. 12)
Lively Mfg. & Equipment Co.. (1. 3. 5. 23)
Long-Airdoi Co A Div ol the Marmon Group, Inc.,
(2.3.4.5.9. 10. 12. 13. 14. 16.20.23)
Machinowpon. (2 9)
Manufacturers Equipment Co.. The. (1.3.5.6.9.
12. 13. 19)
Marathon Mlg Co.(3. 23)
Marsh. E F. Engineering Co. (1. 3. 5. 6. 8. 10.
12. 13. 17.20.33)
McNaHy Pinsburg Mlg Corp.(1.3. 19,22,23)
Mineral Services Inc. (12)
Mining Equipment Mfg Corp.. (3)
Mining Machine Parts. Inc.. (9)
Mining Progress Inc , (2. 9)
Mining Supplies. Ltd . (2. 9. 15. 17)
Mmiec International. Div ol Barter Greene. (3,
5. 7. 17. J3>
Myers-Whaley Co. (I. 3)
National Air V.bralo. Co. (21)
National Iron Co. (U
National Mine Semcu Co. (2. 9)
Ore Reclamation Co. (3. 19)
Owens Mlg Inc . (3. 4. 5. 10)
Peerless Conveyor & Mlg Co. Inc.. (3, 5. 23)
Persmgers Inc
Portec. Inc. Pioneer Div. (1. 3. 5, 12. 17. 20.
23)
Re»nordlnc.,(l,3. 5,6, 9. 12. 13.21)
Reunion] Inc.. Process Machinery Uiv.. (3. 5. 6,
17)
Rish Equipment Co., Material Handling Systems
Div.
Rock Industries Machinery Corp, (1. 3, 6, 17,
20. 23)
Rubber Engineering 4 Mfg Co, (3. 6)
Sala International. (1.2. 3)
Salem Tool Co. The. (12)
Savage. W J Co.. (3)
Schroeder Bros Corp. (3)
Serpenlu Conveyor Corp.. (3.5.10, 12.13.15.
17,20.22,23)
Simplicity Engineering. (21)
Specialty Services. Inc.. (3)
Sprout-WakJron. Hoppers Co.. Inc. (3.6.12.19)
Slamler. W R.. Corp.. The. (5. 12. 13)
Standard Metal Mlg. Co, (3. 5, 6, 12)
Stephens Adamson (1. 3, 13. 21. 23)
Sturtevant Mill Co.. (19)
Telsmith Div.. Barber-Greene Co, (3. 5, 17.23)
Underground Mining Machinery Ltd.. (2).
Unifloc Limited
Untlok Belting Co.. Div. of Georgia Duck and Cord-
age Mill. (3)
Universal Industries. (3. 6. 12)
Universal Road Machinery Co.. (3. 6)
Vibcolnc.. (21)
Vibranetics. Inc.. (12. 21)
Vibra-Screwlnc. (5. 21)
Wa|a< Industries Ltd.. (2, 3. 4, 9. 15, 20. 23)
Webb. Jems B.. Co.. (I. 3. 4. J. 6.8. 9. 10. 12.
17. 18. 19.20.21.23)
Webster Mlg Co., (1. 3. 5,6,9.10,12,13,19.
20.21.23)
West Virginia Armature Co.. (3. 4. B. 14)
West Virginia Belt Sties 4 Repairs Inc.. (1. 3. 6,
9. 12.21)
Willis 4 Paul Corp.. The. (3. 5. 6. 9. 10. 12. 19.
20, 23)
Wilmol Engineering Co.. (9. 12)
Wilson.R.M.Co..(1.3. 5.6.9. 10.11.12.13.
17, 18, 19,20.21,23)
CRUSHER REPLACEMENT
PARTS
Alhs-Chalmers
Allis Chalmers. Crushing 1 Screening Equipment
American Pulverizer Co.
Amsco Div.. Aben Corp.
Birdsboro Corp.
British Jeffrey Diamond. Div. of Dresser Europe
SA. (U.K. Branch)
Columbia Steel Casting Co. Inc
Eagle Crusher Co. Inc.
ESCO Corp.
Fairmont Supply Co.
Frog Switch Mfg Co.
Hammermills, Inc.. Sub of PettiDone Corp
Iowa Manufacturing Co.
Jeffrey Mfg Div. Dresser Industries Inc
Laubenstein Mfg. Co.
Manufacturers Equipment Co.. The
McLanahan Corp.
Pennsylvania Crusher Corp
Pettibone Corp.
Portec, Inc. Pioneer Div.
Resisto-Loy Co.
Rexnord Inc.. Process Machinery Div.
Rock Industries Machinery Corp.
Steel Heddte Mlg Co.. Industrial Div.
Telsmith Div. Barber-Greene Co.
Thomas Foundries Inc
Williams Patent Crusher A Pulv. Co.
Wilson. R M.. Co.
CRUSHERS
HAMMER
IMPACT
JAW
IABOKA10NY
RING
HOI.I
Mill lISIAtll
A|[t>ii*Mr% I i|iii|inuliil Ini . (.11
Mb: I lulmnv (.1)
Allis Clialnwis. Cnisliing A :«'it!i'"iMK I il
inrnl. (?. 3)
Am,.|,t.inl'ulvmiJerCo.(l. ?. 4. 5.0)
Amxler Mine A Smelter Supply. (4)
Barber Greene Co . (3. 6)
Birdsooro Corp, (3)
Bonded Scale & Machine Co. (6)
British Jeffrey Diamond Div ol Dresser Europe
S.A (U.K Branch). (1.2 4 6)
Duple! Mill 4 Mlg Co. (1.6)
Eagle Crushei Co.. Inc. (I. 2. 3. 6. 7)
El-Jay, Inc.
Fairmont Supply Co, (1. 2. 7)
Fate-International Ceramic A Processing Equip-
ment. Div. ot the Fate Root Heath Co a Bdn
ner Co. (6)
Frog Switch Mlg Co. (2)
Fuller Co. A Gal. Co. (3 6)
GEC Mechanical Handling Ltd. (I. 2. 3 5, 6)
Gruendler Crusher 1 Pulveruer Co.. (1. 2. 3. 4.
5. 6, 7)
Gundlach. T. J.. Machine Co.. Div J M J Indus-
tries. Inc.. (2. 6. 7)
Hammermills. Inc. Sub ol Peltibone Corp .(1,2.
3. 4, 6)
Hemscheidl America. (3)
Hensley industries Inc. (5)
Hewitt-Robins Oiv. Litton Systems. Inc. (1. 2. 3)
Holmes Bros Inc. (4)
Iowa Manufacturing Co. (1. 2 3. 6)
Jeffrey Mfg Div. Dresser Industries Inc. (1,2. 7)
Joy Mlg Co. Denver Equipment Div.. (3.4.6)
KHD Indusineanlagen AG. Humboldl Wedag. (I
2. 3. 4. 5. 6)
KoppersCo.lnc.il. 2. 5. 6. 7)
Koppers Co. Inc Metal Products Div.. Hardmge
Operation. (1 2. 5. 6)
Machmoeiport. (13. 6)
Maiac Oiv . Donaldson Co. (2)
Manulacnners Equipment Co.. Ihe
McLanahjn Corp. (3 6 7)
McNilly P.ttsburg Mlg Corp. (6)
Mine 4 Smelter Industries. (3. 4)
Mineral Services Inc. (6)
Mining Progress. Inc . (3. 6. 7)
Morse Bros Machinery Co. (3. 4)
Owens Mlg. Inc. (2)
Pennsylvania Crusher Corp. (1. 2. 3.4. S. 6. 7)
Portec, Int. Pioneer Div. (1 2. 3. 6. 7)
Preiser/Mineco Div. Preiser Scientific Inc (1 3
4)
Pulven/ing Machinery, Div. of MikroPul Corp. (1.
2.4)
Resisto-UyCo.(3)
Reword me. Process Machinery Div. (1.2. 3.6)
Rish Equipment Co Inll
Rish Equipment Co.. Material Handling Systems
Div
Rock Industries Machinery Corp. (1. 2. 3. 6)
S A S Machinery Sales. Inc. (2)
Sala International. (4)
Schroeder Bros Corp. (6)
Simplicity Engineering. (1.2)
Smico Corp. (1)
Soiltest, Inc. (4)
Sprout-WaWron. Koppers Co. Inc. (1. 6)
Sledman Fdy. & Mach Co (I 2.4 5 6 7)
Steel Meddle Mlg Co. Industrie! Div . (1. 2. 5)
Straub Mfg Co, (3)
Slurtevant Mill Co.. (I. 2,3.4. 5.6)
Telsmith Div.. Barber-Greene Co. (3. 6)
Universal Road Machinery Co. (3)
Williams Patent Crusher A Pulv Co.. (I 2 4 5.
6)
Wilmol Engineering Co.. (6)
Wilson. R.M. Co. (2. 4. 6. 7)
Workman Developments. Inc. (4)
CRUSHING PLANTS,
PORTABLE
Aggregates Equipment Inc
Alhs Chalmers
Aids-Chalmers. Crushing A Screening Equipment
Barber Greene Co. •
British JeMrey Diamond. Div ol Dresser Europe
SA (UK Bnnch)
Eagle Crusher Co , Inc
M lay. Inc
GIOMIN
Gnwndler Cnishrr 4 Pulverilpr Co
HamiTWrinilll. Ini . Sub Ol f'eltibone Corp
HnnMin R A . DiK . tld
Hi-.ill Rnlnnt Ikv . tiltrm Sytlrmt. Inc
InduilHcl (.ontf acting ol (•itmonl. Inc
kma Maniilwtiirmg Co
li'lficy Ml»; Div . Uraiscr Industries Inc
KHD Induslnuanlagnfl AG. Humboldl W«Ug
I ngan Corp
MrDowell-Wfllman Fngrg Co
700
-------
Mintec/lntemational. Oiv of Barber-Greene
Pennsylvania Crusher Corp.
Portec. Inc., Pioneer Div.
Reinord Inc.. Process Machinery Oiv.
Rish Equipment Co. Intl.
Rish Equipment Co.. Material Handling Systems
Div.
Rock Industries Machinery Corp.
Stedman Fdy. & Mach. Co.
Straub Mfg. Co
Telsmith Oiv.. Barber-Greene Co
Wilson. R. M.. Co.
CRUSHING & SCREENING
PLANTS, PORTABLE
Aggregates Equipment Inc.
Allis-Chalmers
Mis-Chalmers, Crushing & Screening Equipment
Barber-Greene Co
British Jeffrey Diamond. Div. ol Dresser Europe
S.A. (U.K. Branch)
Eagle Crusher Co.. Inc
El-Jay. Inc.
GEOMIN
Gruendler Crusher & Pulverizer Co.
Hammermills. Inc.. Sub of Pettibone Corp.
Hanson, R.A.. Disc., Ltd.
Hewitt-Robins Div., Litton Systems. Inc
Industrial Contracting ol Fairmont. Inc
Iowa Manufacturing Co
Jeffrey Mfg Div.. Dresser industries Inc.
KHD Industneanlagen AG. Humboldl Wedag
Logan Corp
Machinoexporl
McDowell-Wellman Engrg. Co.
Mintec/lnternational. Div. ol Barber-Gieene
Portec. Inc.. Pioneer Div
Reinord Inc. Process Machinery Oiv.
Rodi Industries Machinery Corp.
Stedman Fdy & Mach. Co
Straub Mfg. Co.
Telsmith Div.. Barber-Greene Co.
Wilson. R. M. Co.
CYCLONES. OUST
COLLECTING
Aerofall Mills Ltd
American Air Filter Co.. Inc.
American Alloy Steel, Inc.
American Standard. Industrial Products Oiv
C-E Raymond/Bartlett-Sno*. Div. Combustion
Engineering. Inc.
CMI Corp
CSE Mine Service Co
Carborundum Company
Donaldson Co. Inc
Ducon Co. Inc.. The
Duple. Mill 4 Mlg. Co
Ferro-Tech, Inc.
Fuller Co. A Gal. Co
General Resource Corp.
Industrial Contracting ol Fairmont, Inc
Iowa Manufacturing Co.
KHD Industrieanlagen AG, Humboldl Wedag
Lmatex Corp. ol America
McNally Pittsburg Mfg. Corp.
NFE International Ltd
Process Equipment, Stansteel Corp.
Research-Cornell, Inc.
Sproul-Waldron. Koppers Co.. Inc.
Unifloc Limited
Western Precipitation Div.. Joy Mfg Co.
CYCLONES, HEAVY MEDIUM
(SEE WASHERS)
CYCLONES WATER
TREATMENT
American Alloy Steel. Inc.
Cyclone Machine Corp.
Daniels Company. The
Dorr Oliver Long. Ltd.
Draw Corp.
Heil Process Equipment Co.. Div of Dan Indus-
tries, Inc.
Heyl 4 Patterson, Inc..
Krebs Engineers
McNally Pittsburg Mlg. Corp.
Mineral Services Inc.
Sala International
Telsmith Div., Barber-Greene Co.
Unifloc Limited
WEMCO Div.. Envirotech Corp.
CYLINDERS
1. ELECTRIC
2 HYDRAULIC
Aniiler Mine & Smelter Supply. (2)
A-TOInc.. (2)
Brunmg Co.. (2)
• ENERPAC. Div. of Applied Power Inc.. (2)
Fairmont Supply Co.. (2)
Gulbck Dobson Intl. Ltd.. (2)
Guyan Machinery Co. (2)
HYCO. Inc., Sub. of The Weatherhead Co. (2)
Iowa Industrial Hydraulics, Inc.. (2)
Lebco, Inc.; Illinois Div. (2)
Marion Co.. Oiv ol Sycon Corp. (2)
McDowell-Wellman Engrg Co.. (2)
Mining Equipment Mtg. Corp., (2)
Porter. H K., Inc.. (2)
Raco International. Inc. (1)
Reinord Inc.. (2)
Templeton. Kenly & Co., (2)
Tol-0-Matic, (2)
WABCO Fluid Power Oiv, an American-Standard
Co, (2)
. Ward Hydraulics Div.. ATO Corp. (2)
Weatherhead Co. The, (2)
Wilson. R M., Co.. (1)
DENSITY MEASUREMENT &
CONTROL
Automation Products. Inc.
Beckman Instruments, Inc
Daniels Company, The
Halliburton Services-Research Center
. Kay-Ray Inc
K-Tron Corp. '
Mine 4 Smelter Industries
Ohmarl Corp
Preiser/Mineco Div.. Preiser Scientific Inc.
Texas Nuclear
TOTCO Div -Baker Oil Tools. Inc.
Wilmot Engineering Co
DEPRESSANTS
Preiser/Mineco Div. Preiser Scientific me
DRIVES
1. ADJUSTABLE & SELECTIVE
SPEED
2 BELT
3. CHAIN
4. FLANGE-MOUNTED
5 FLUID. HYDRAULIC
6 GEAR. WORM-GEAR
7. SHAFT-MOUNTED
8 VBELT
9. VARIABLE-SPEED
10 VARIABLE SPEFO. HYDRAULIC
11. EDDY-CURRENT
Allen Bradley Co. (I. 9)
AllisChalmers, (I)
American Poclain Corp, (5. 101
American Standard, Industrial Products Oiv. (1.
2.5)
Banner Bearings. (1. 2. 3 6. B. 9)
Big Sandy Electric 4 Supply Co. Inc .(1.2 3. 4.
5. 6. 7. 8. 9)
Bonded Scale 4 Machine Co. (2. 3. 6. /)
Boston Industrial Products Oiv.. Amciican buinte
lix . (2. 8. 9)
Browning Mlg Div.. Emerson Electric Co . (2. 3.
6, 7. 8. 9)
CSE Mine Seivice Co. (2)
Coeur d'Alenes Co . (1. 2, 5, 6. 7. 9. 10. II)
Compton Electrical Equipment Corp (1, 11)
Cone-Drive Gears. A Unit ol E i-Cell 0 Corp.. (4.6.
7)
Continental Conveyor & Equipment Co, (7)
Controlled Systems Inc.. (1, 2.9)
Cutler-Hammer. Inc., (1, 9)
OaycoCorp. Rubber Products Div. (1. 2. 8, 9)
Dick Inc R I. (1.2. 8. 9)
Dodge Div. Reliance Electric Co. (2. 3. «. 5. 7.
B)
Dominion Engineering Works ltd . (6. 7)
DowtyCorp,(2 4.9)
Duple. Mill & Mtg Co. (2 3 7.8.9)
Dyne< Div. Applied Power Inc (S. 10)
Eaton Corp. World Headquarters. (I. 2.4. 5 6.
I. B 9)
Eaton Corp. mduslridl Drives Or. (I. 2 4.6 7.
8. 9. II)
Electric Machinery Mlg Co.(1, 9. 11)
FMCCorp Drive Div. (1. 5 6. 7 9)
FMCCorp Pump Div . (5. 9. 10)
Fairmont Supply Co. (t. 2. 3. 4 6. 7. 8. 9)
FalkCorp, The (1 4, 5.6 7.9 10)
Federal Supply 4 Equipment Co Inc (5)
Fluidrive Engineering Co Ltd . (5. 10)
Formsprag Co. (5, 9)
GEC Mechanical Handling Ltd 110)
GTE Sylvanki inr. . (1 9)
Gales Rubber Co. The. (I 8)
Gewral Electric Cu. DC Motor 4 Generator
Oept.(l)
General Electric Co. industrial Sales D>«. 11.2.3
4.6. 7. 8 9. Ill
Goodman Equipment Corp. (?)
Harnischleger Corp .11)
HuwooJ Irwm Co . (2, 3 0)
Huwood Limited (I. 2. 3. 4)
Illinois GtJr 'Wallace Muiray Corp (6)
Industrial Rubber Products Co , 11 1. 3. & 7. 8.
9)
Kanawha Mlg Co
Koppers Co . Inc (1.7.9)
Leeds 4 Northrup Co. (9)
Lee Supply Co. Inc. (9)
Lima Electric Co. Inc. (1)
Logan Corp, (2, 3.6. 7.8. 9)
Louis Allis Di<. Litton indu.ln ji Products Inc II.
2.3.4.6.8,9. 11)
Lucas Industries. Fluid Power UK 15. 10!
Mining Progress. Inc .(1. 4. 5 7)
Mining Supplies. Ltd. (3 4)
MorseChain.Div olBorg Warner Corp (I 2.3
6, 7. 9)
National Iron Co.. (7)
Owens Mfg Inc . (2)
Philadelphia Gear Corp .(1,6.7.9 10)
Power Transmission Oiv . Dresser Industries Inc .
(1 2.4.6. 7.9)
Rai o International. Inc. (I)
Reliance Eleclr,c Co. (I. 2. 4. 6. 8 9 11)
Re«nordlnc.(3. 5)
Robbins t Myers. Inc . (1. 4. 6. 7. 9)
Robicon Corp. (9)
Rockwell Standard Oiv. Rockwell international
Corp. (6)
Sperry Vickers Oiv. Speny Rand Corp ,(1,5.10)
Sperry Vickers. luisa Div. (4, 6. 7)
Steel Hefldk Mfg Co. industrial Div (1.2.9)
Sterling Power Systems. Inc.. A Sub ol the I end
Corp, (4. 6. 9)
Tool Steel Gear * P«ion Co. (6)
1 win Disc. Inc. (1. 5)
U S Electrical Mi.lurs Div Emerson Electric Co
(I 4. 6. 7. 9. II)
Webb. Jervis 8. Co
West Virginia Armalure Co. (2)
West Virginia Bell Sales i Repairs Inc.. (2 3)
Westmghcuse Electnc Corp (169)
Wichita Clutch Co.. Inc. (9)
Wilmot Engineering Co, (8)
Wood's. T B. Sons Co. (1. 2. 7.8. 9. 10)
DRYERS
1 CENTRIFUGAL
2 CENTRIFUGAL, SOLID BOWL
3. COAL. S TEAM-PROCESS
4 THERMAL
5 THERMAL CONTINUOUS
ROTARY
6. THERMAL. FLUIDIZED-BEO
7. CENTRIFUGAL. VIBRATING
Aggregates [quipmenl he. (5)
Alu Chalmers. (51
Amolek. (1. !, 5. 6)
Bethlehem Sinel Corp .(12)
B'ia Machine Co. Inc (I 2 7)
C-E Raymond'SaMletl Snow On ComOusi.on
Engineering, Inc. (4. 5. 6)
Centrifugal & Mechanical industries, Inc. (1. 2.
Dorr Oliver Inc. (6)
Envirotech Corp Eimcp BSP Div .(45)
701
-------
FMC Corp., link-Bell Material Handling Systems
Div. (5. 6)
Fairmont Supply Co, (1)
Feeco International, Inc., (5)
Fuller Co. A Gati Co., (t>)
GEC Mechanical Handling Ltd.. (5)
Heyl & Patterson, Inc.. (I. 4. 6, 7)
Holmes Bros Inc. (4)
Indiana Steel & Fabricating Co. (4)
IrvinMcKelvyCu. The. (5)
Jellrey Mlg Div . Dresser Industries Inc , (4, 6)
Johnson Div, Universal Oil Products 13)
joy Mfg Co. Denver Equipment Div . (4)
KG Industries Inc . (4, 5. 6)
KHD Industrieanldgen AC. Humbnldt We.fag, (6)
Kennedy Van Saun Corp. Sub. ol McNally Pitts-
burg. (5, 6)
Koch Engineering Co. Inc, (6)
Koppers Co.. Inc. M..-.«l Products Div.. Hardmge
Operation. (3. 5)
Laubenstem Mlg. Co.. (1)
Lively Mlg. & Equipment Co, (1,4)
McDowell-Weliman Engrg .Co. (5)
McNally Pittsbuig Mlg Corp.. (1, 4. 6. 7)
Pall Corp. (3 4)
Panerson-Kelley Co.. Div. ol Taylor Whanon Co
• Harsco Corp . (5)
Porlec. Inc. Pioneer Div.. (5)
Process Equipment. Stansleel Corp. (5)
Sala International. (5)
Steams-Roger Inc.. (5)
WEMCO Div. Envirotech Corp. (7)
Whiting top. (5. 6)
Wiimol Engineering Co.. (5)
DUCT, AIR
American Alloy Steel. Inc
Armco Steel Corp. Product Inlo.
Davis Instrument Mfg Co
Fairmont Supply Co.
Federal Metal Hose Corp
Fiberglass Resources Corp.
Fleiaust Co.. Div. ol Callahan Mining
Heil Process Equipment Co.. Div. of Dad Indus-
tries. Inc
in Holub Industries
Industrial Rubber Products Co
johnston-Morehouse-Dickey Co.
Kanawha Mlg. Co.
lee Supply Co. Inc
login Corp
National Mine Service Co.
PeabodyASC
Porter. H K Co. Inc
Preiser/Mineco DIV . Preiser Scientific Inc.
Schauenburg Flexadux Corp
United McGill Corp.
Waiai Industries Ltd
West Virginia Belt Sales I Repairs Inc.
Wilson, R M., Co.
DUST-COLLECTOR BAGS,
TUBES
Aerofail Mills Ltd
Aggregates Equipment Inc
Air Correction Div , • UOP
American Air Filter Co, Inc.
Bemis Co.. Inc
C-E Raymond/Bartlerl-Snow, Oiv. Combustion
Engineering. Inc
Daniels. C. R, Inc.
Fairmont Supply Co.
Ferro-Tech. Inc
Firestone Tire & Rubber Co
Johnson-March Corp, The
KHD Industneanlagen AC. Humboldl Wedag
Logan Corp
MikroPul Corp
Mme Safety Appliances Co.
National Filler Media Corp
Peaoody ABC
Preiser/Mineco Div, Preiser Scientific Inc
Smico Corp.
Sproul-Waldron, Koppers Co, Inc.
Standard Metal Mlg. Co
Ton! Div. Donaldson Co Inc.
Wheelabrator Frye Inc, Air Pollution Control Div
Wilson. R M, Co.
Wire Cloth Enterprises. Inc.
DUST COLLECTORS, COAL
HANDLING, PREPARATION
Aggregates Equipment Inc.
Air Pollution Control Operations. FMC Corp.
American Air Filter Co, Inc.
American Alloy Steel. Inc
American Standard. Industrial Products Div
CSE Mine Service Co.
Donaldson Co. Inc.
Dravo Corp
Ducon Co, Inc, The
Erwimiu-enng. Inc.
Fairchiid. Inc
Ferro-Tech. Inc
Fuller Co, A Gati Co
General Resource Corp
Industrial Pneumatic Systems. Sub of Industrial
Contracting ot Fairmont. Inc
Johnson-March Corp, The
Joy Mlg Co.
Joy Mlg Co. (UK.) lid
KHD tndustneanlagen AG. Humooidl Wedag
Kanawha Mlg. Co.
Krebs Engineers
McNally Pittsburg Mlg Corp.
MikroPul Corp .
Mineral Services Inc.
Peabody ABC
Preiser/Mmeco Oiv. Preiser Scientific Inc
Research Cornell. Inc.
Sly. W W. Mlg Co.
United McGill Corp
Vorte« Air Corp.
West Virginia Bell Sales 4 Repairs Inc
Western Precipitation Oiv . Joy Mfg. Co
Wheelabrator-Frye Inc . Air Pollution Contiol Du
Willis & Paul Corp, The
Wilson. R. M . Co.
DUST COLLECTORS, SHOP,
LABORATORY, ETC.
Aggregates Equipment Inc.
Air Correction Div, • UOP
American Air filter Co. Inc
American Standard, Industrial Products 0>v
Ducon Co, Inc, The
Environeermg. Inc
Fairchiid, Inc.
Ferro-Tech. Inc.
Fil-T-Vac Corp,
Fisher Scientific Co.
General Resource Corp
Heil Process Equipment Co, Oiv. of Dart indus-
tries, inc.
ITT Holub Industries
Johnson-March Corp. The
MikroPul Corp
National Mine Service Co
Research-Cornell. Inc
Rockwell International. Power Tool Div
Sly. W W , Mfg Co.
Sprout-Waidrcn, Koppers Co. Inc.
Torit Div Donaldson Co. Inc.
United McGill Corp
Wheelatirator-Frye Inc, Air Pollution Control Div.
DUST-CONTROL &
DUSTPROOFING
EQUIPMENT & LIQUID
COMPOUNDS
Adams Equipment Co. Inc.
Aquadyne. Div ol Molomco. Inc.
Communication & Control Eng. Co. ltd
Deron R & D Co. Inc
Donaldson Co, Inc
Dowel) Div ol the Dow Chemical Co
Ferro-lech, Inc
Grmden-CWI Distributing Co
Hayden Nilos Conflovt ltd
Houghton & Co. E. F.
Industrial Pneumatic Systems Sub ol Industrial
Conloctmg ot Fairmont. Inc
Johnson-March Corp. The
Nalco Chemical Co
National Mine Service Co.
Preiser/Mtneco Div. Preiser Scienlilir. ini.
Shell Chemical Co. Chemical Sales
Slv. W W. Mfg Co
Spraying Systems Co
Trelleborg Rubber Co , Inc.
Uniroyal, Inc
Viking Oil 4 Machinery Co
Wen-Don Corp
Wilson. R. M . Co
ENGINEERS
I BLASTING-VIBRATION
2 ELECTRICAL
3 FACIlllr DESIGN &
CONSTRUCTION
4 FLOTATION
5 GEOLOGY
6. INDUSTRIAL
7. MECHANICAL
8 MINING
9. PREPARAFION
10 STRIPPING
1 1. MINE-MANAGEMENT
12. GEOTECHNICAl. (SOIL AND
ROCK MECHANICS. SLOPE
STABILITY)
13 CIVIL
14 DAMS
15 ARCHITECTURE
Aggregates Equipment Inc, (?. 3, 6. 7, 13) '
Allen i Garcia Co. (2. 3. 7. 9. 13)
Alias Po«der Co, (1)
Atlas Railroad Construction Co. (13)
Austin Powder Co. (I)
Badger Construction Co, Div. of Mellon-Stuart
Co. (3, 9)
Barnes & Remecke. inc.. (2. 3. 6. 7. 13)
Beaumont. Edward C, (5. 6)
Ben Laboratories. (3)
Blaw-Kno> Equipment. Inc, (3)
Boggess. B I. Co. Mine Development Group
Bcyd. John! Co. (5, 8. 9, 10. II)
British Jeffrey Diamond. Div ol Dresser Europe
S A (U K Branch). (2. 6. 7. 8)
brown Mining Construction Co. (3)
Catalytic. Inc, (3)
Cementation Co ol America. Inc. (3. 8)
Cementation Mining Ltd. (3, 5, 7.8.12.13.14)
Collins Radio. (2)
Commercial Telling & Engineering Co. (4.8.9)
Complon Electrical Equipment Corp, (2)
Continental Conveyor & Equipment Co, (2. 3. 7,
8 9. 1J)
Daniels Company. The. (3. 4. 7. 9)
Daws. J J. Associates. Inc. [6. 8. 9. II)
Dover Conveyor I Equipment Co. Inc (2. 7)
DOMII Oiv of the Oow Chemical Co. (9)
Dravo Corp (3. 9)
du Ponl de Nemours, t I 4 Co Inc
Envirospherc Co
FMC Corp . Link Bell Mittnll Handling Systems
Div. (9)
Fairlwld Engineering Co (2. 7)
F«co International Itx , (3)
Ferguson. HK, Co. 131
Ferro Tech. Inc. (3. 6. 9)
F.illertrxv Hodgart I Barclay ltd . (/)
GEC Mechanical Handling ltd, (3 7. 9)
Galigher Co. The. (4;
Gates Engr Co, (3.4, 5.6.7. 8. 9. 10. II. 13.
14. 15)
Geometries (5. 13)
GEOMIN. (1.2. 3.4.5.6, 7.8.9 10. II. 12.
13, 14)
Colder Associates. Inc . (5. 8. 11 12. 13)
Hammermills Inc. Sub 01 Petiiboiie Corp. (3)
Hanson RA, Disc .lid
Haien Research Inc . (4. 5. 9)
Head Wnghtson t Co ltd, (9>-
Hewitt-Robins Conveyor Equipment Div Lifton
Systems, Inc, (8)
Hewitt Robins Div, lilton Systems, Inc, (3. 7. 8)
Heyl i Patterson. Inc, (3. 4. 9)
Holfey. Kenney. Scnon. Inc, (2. 3. 6. 7, 9. 13)
Industrial Contracting of Fairmont. Inc. (3. 7. 9)
Irvm-McKtrvy Co, The, (3. 9)
Jenkins of Rertont Lid, (2. 3. 4. 6.7. 9. 13)
Joy Mil Co. Denver Equipment On, (4)
Kaiser Engineers. Inc, (2. 3.4, S. 6. 7.8.9.10.
II. if. 13. 14. 15)
Kilbom-MUS. Inc. (3. 6. 7. 8. 9. 10)
.Uke Shore. Inc, (2,3. 7)
lively Mlg. & Equipment Co, (3.9)
Loftus. Peter F. Corp.. (2. 3. 6. 7. 8, 13. 15)
MtcOonald Engineering Co, (2. 3, 6. 7. 13)
Mattwws. At» W, Engineering Co, (2. 3. 7. 13.
15)
McDovrtll-Wellman Engrg Co. (3. 6. 7. 8. 10.
13)
702
-------
McKee. Arthur G. 4 Co.. Western Krtjrpp Eng On..
(3.4.7,8,9,13)
McMally Pittsburg Mfg. Corp., (9)
Mine Engineering t Development Co. (MEDCO),
(5.8, 10. 11, 13. 14)
Mineral Services IK.. (3.4, 5.8.9.11)
Minerals Processing Co.. On. of Trojan Steel Co..
(3.9)
Minuc/lntemationjl. On. ot Barber-Greene. (3)
Montreal Engineering Co. Ltd.. (2. 3. 4. 5. 6. 7.
8.9. 10.11.12.13.14.15)
Multi-Amp Corp.. (2)
National Electrx Coil Div. ol McGraw-Edison Co..
(2)
NUS Corp.. Robinson & Robinson Div.. (3. 7)
O'Dormetli Associates. Inc.. (1.7)
ORBA Corp.. (9. 13)
Patent Scaffolding Co.. (3)
Preiser/Mineco Div.. Preiser Scientific Ix.. (4.8.
9)
Pullman Torkelson Co.. (2. 3. 6. 7, 9. 13)
Roberts 4 Schaefer Co.. (3. 9)
Roller Corp.. (9)
Rust Engineering Co.. A Sub. of Wheelabrator-
Frye Inc.. (2. 3. 6. 7. 13. 15)
Sala International. (4)
Steams-Roger Inc.. (2. 3. 6. 7. 8. 9. 15)
Stephens-Adamson. (3)
Treadwell Corp.. (2. 3. 6. 7. 13)
VME-Nitro Consult Inc.. (1.8. II)
Webb, Jervis 8.. Co.. (3)
Weir. Paul Co.. Inc.. (3, 4. 5, 8. 9. 10. 11)
West Virginia Armature Co.. (2. 7)
Westinghouse Electric Corp, (2)
Willis 4 Paul Corp.. The. (3. 7. 12. 13)
Wilson Engineering Co., (3)
Wilmot Engineering Co. (9)
EYE SHIELDS
AO Safety Products. On. of Amer. Optical Corp.
American Optical Corp
Aniiter Mine 4 Smelter Supply
Bowman Distribution, Barnes Group. Inc.
CSE Mine Service Co.
Fairmont Supply Co.
Fibre-Metal Products Co.
Fire Protection Supplies Inc.
General Scientific Equipment Co.
Industrial Rubber Products Co.
MarbndUe Electric Co
Mine Sltety Apptances Co.
National Mine Service Co.
Pceser/Mmeco Div.. Preset Scientific Inc
Shannon Optical Co.. Inc.
Welsh On. of Teitron
WiDson Products On.. ESB. Inc.
FABRICATORS. BINS,
TANKS & HOPPERS
• Aggregates Equipment Inc.
American Alloy Steel. Inc.
Asbury Industries, Inc.
Bethlehem Steel Corp.
Concrete Equipment Co.. Inc.
Continental Conveyor & Equipment Co
Easlon Car 4 Construction Co
Enterprise Fabricators, Inc.
' Equipment Mlg Services. Inc.
f airfield Engineering Co.
Ferro-Tech. Inc.
Holmes Bros Inc.
HuMOd-lrwn Co
Industrial Contracting ol Fairmont. Inc.
Industrial Pneumatic Systems. Sub ol Industrial
Contracting of Fairmont. Inc.
Industnal Steel Co.
Kanawha Mfg. Co.
1 Lake Shore. Inc.
Laubenstem Mfg Co
leman Machine Co
Lively Mlg 4 Equement Co.
Mathewv Abe W.. Engineering Co.
McDowell Wetlman Crfrt Co
McNHy Pitfsburj Mtf Corp
Muw.it Sim Oiv . Ua~n\ Cor
Webb, Jervis B, Co.
West Virginia Belt Sales 4 Repairs Inc.
Willis 4 Paul Corp.. The
Wilmot Engineering Co.
Wilson. R. M., Co.
Workman Developments. Inc.
FABRICATORS, STEEL &
STRUCTURE
Aggregates Equipment Inc.
Babcock 4 Wilcon
Blaw-Knoi Equipment, Inc.
Brown Mining Construction Co.
Canton Stoker Corp.
Coeur d'Alenes Co
Continental Conveyor 4 Equipment Co.
Dover Conveyor 4 Equipment Co, Inc.
Dourly Corp.
Oravo Corp.
Enterprise Fabricators. Inc.
Equipment Mlg Services. Inc.
Fairfiekj Engineering Co.
Falk Corp, The
Greenbank Cast Basalt Eng Co ltd.
Huwood-lrwn Co.
Industrial Contracting ol Fairmont. Inc.
Industrial Steel Co.
Jennmar Corp.
Kanawlia Mlg Co.
Lake Shore. Inc.
Leman Machine Co.
Lively Mlg 4 Equipment Co.
Manson Services, Inc.
Mathewv Abe W., Engineering Co
McDowell Wellman Engrg. Co
McLanahan Corp.
Midwest Steel Oiv, Midwest Corp.
Mining Equipment Mlg. Corp.
Mining Supplies, Ltd.
Ore Reclamation Co.
Rise Corp.
Sanford-Day/Marmon Transmotive. Div. ol the
Marmon Group. Inc.
Somerset Welding 4 Sleel Inc.
Specialty Services. Inc.
Standard Metal Mlg. Co.
Sturtevant Mill Co.
United States Steel Corp.
Willis 4 Paul Corp, The
Wilson. R. M, Co.
FACE SHIELDS
AO Safely Products, Div. of Amer. Optical Corp.
American Optical Corp.
Aniiter Mine 4 Smelter Supply
Bowman Distribution, Bames Group, Inc.
Bdlerd. E. D. Co.
CSE Mine Service Co.
Fairmont Supply Co.
Fire Protection Supplies Inc.
General Scientific Equipment Co
Industrial Rubber Products Co.
Lincoln Electric Co, The
3MCo
Martindale Electric Co.
Mine Safety Appliances Co.
Mining Equipment Mlg. Corp.
Preiser/Mineco Div, Preiser Scientific Ix.
Shannon Optical Co, Inc.
Snap-On Tools Corp.
Welsh Div. ol Textron
Willson Products Div, ESB. Ix.
FAN SIGNALS
General Equipment 4 Mlg Co . Ix.
Huwood-lrwin Co.
Jabco. Ix.
Jeffrey Mining Machinery On . Dresser Industries
Inc
Ler Supply Co, Ix.
National Mine Service Co
e. Inc.
General Resource Corp.
Guyan Machinery Co
Heil Process Equipment Co. D» ol Dart Indus-
tries, Inc.
ITT Holub Industries
ILG Industries. Oiv. ol Carrier Corp
Jeffrey Mining Machinery Div, Dresser Industries
Inc
Joy Mlg Co.
KHD Induslrieanlagen AC, HumboWt Wedag
Koppers Co, IK.
Manufacturers Equipment Co, The
Mathews. Abe W.. Engineering Co.
New York Blow Co.
PeabodyABC
Porter. H.K. Co.. Inc.
• Preiser/Mineco On, Preiser Scientik Ix
Robinson Industries. Inc.
SchauenDurg Fleiadux Corp
Sprout Wauron. Koppers Co. Ix.
Westinghoute Electric Corp
FANS. VENTILATING
CSE Mm Service Co.
Fairmont Supply Co.
Fuller Co. A GaU Co
General Resource Corp
Guyan Machinery Co
Haxo International Div ol Hannon Electric Co.
Hed Process Equipment Co, Div. of Dan Indus-
tnev Ix.
HeroU Mlg Co.
ITT Holub Industries
ILG Industries. Oiv. of Carrier Corp
Jeffrey Mining Machinery On, Dresser Industrie]
Inc.
Joy Mfg Co.
Koppars Co, Ix.
Lee Supply Co, Ix.
Manufacturers Equipment Co. The
Ne« York Blower Co. .
PeabodyABC
Porter. H.K Co, Inc
Preiser/Mineco On, Preiser Scientific IK.
Robinson Industries, IK.
Schauenburg Fkuadui Corp
Sprout-WaUron. Koppers Co. IK
Wajai Industries ltd.
Westmghouse Electric Corp.
FEEDERS
1. APRON
2. CHAIN
3. CHEMICAL, CHLORIDE, LIME.
REAGENT, ETC.
4. CONTINUOUS-WEIGHING
5. GRI2ZIY
6. MINE -CAR HANDLING
7. MINE TRANSFER TO BELT OR
CAR
8. OSCILLATING
9. PI-ATE
10. RECIPROCATING
11. ROTARY
12. SCREW
13. VIEIRAT1NG
Aggregates Equipment
Atlis-Chalmers. (13)
Ix. (1.5. 12. 13)
RistCorp
Somerset WeMiruj, 4 SMI Inc.
Specialty Services. Inc.
Standard Metal Mfg. Co.
Sturtevant Mill Co.
Tretleborg Rubber Co.. Inc.
Uniroyal. Inc.
United States Steel Corp
FANS, BLOWING. EXHAUST
American Atr Filter Co . Ix.
Amu nan Standard. Industrial Products On
CSE Mine Service Co.
Dresser industries. Ix, Industrial Products Div.
Fairmont Supply Co
Fuller Co . A Gatx Co
Atlis-Chalmers. Crushing 4 Screennvj Equip-
ment. (5. 13)
AutoWeiRhlx (1. 3)
Barber-Greene Co, (1. 5. 9. 10. 13)
BIF a unit ol General Signal. (3. 4. 12)
Bonded Scale 4 Machine Co. (9. 10)
Brantord Vibrator Co, The, Div of Electro Me-
chanics. Inc. (13)
Caujon Corp, (3)
Campbell Cham Co, (2)
Canton Stoker Corp, (10. 12. 13)
Card Corp. (II)
Oman Industries. Ix. (3. 5. 7. 12. 13)
Cams Chemical Co. (3)
ClarksonCo.(3)
Connettsnlle Corp. (1.2.6. 9. 10. 13)
Crane Co, (3)
Oeister Machine Co, rx, (5. 13)
Dorr Oliver Long. Ltd. (1. 2. 5. 11)
Dover Conveyor 4 Equipment Co., Ix, (1. 2. 8.
9. 10. 12, 13)
Erci Magnetics. (5. 13)
E SCO Corp. (11)
FMC Corp. Unk-Betl Material Handling Systems
On, (1.5. 10. ID
703
-------
FMC Corp.. Material Handling Equipment Div.. (3.
4. 5, 13)
FtirMI Engineering Co.. (1, 2. 9.10.12)
Fairmont Supply Co.. (1. 12. 13)
Ferro-Tech, Inc.. (3)
Fuller Co., A Gat» Co.. (1,5.11)
GEC Mechanical Handling Ltd.. (1.5.9. II. 12.
13)
Galigher Co, The. (3, 9)
General Kinematics Corp. (5. 8. 13)
General Resource Corp, (II. 12.13)
Gmendler Crusher* Pulverizer Co, (1.5.9,10.
12)
MammerroiUs, Inc.. Sup. ol Pettibone Corp.. (1.5.
• 9. 10. 13)
Hanson. RA, Disc. Ltd
Hewitt-Robins On., Uton Systems. Inc, (1. 5.8,
10. 13)
Heyl I Patterson. Inc.. (6. 10)
Howe Richardson Scale Co.. (4)
Industrial Contracting ot Fairmont, Inc.. (1, 2. 7,
9. 10. 12)
Industrial Pneumatic Systems, Sub. ol Industrial
Contracting ol Fairmont, Inc.. (2)
Into Rnometnc Sole Inc.. (4)
low Manufacturing Co.. (1.5.10. 13)
Irvin-McKetvy Co.. The. (9. 10. 11)
Janes Manufacturing Inc.. (1.2)
Jeffrey Mlg. On, Dresser Industries Inc, (1,4.5.
8, 12. 13)
Jenkins o) Rettord Ltd, (6)
Joy Mfg Co.. Denver Equipment Div.. (3)
KHO Wustnearilagen AC, HumboUt Wedag, (1.
2.5.13)
KanawhaMtg Co., (1.6. 10)
Kolborg Mlg. Corp., (9, 10, 13)
toppers Co, Inc. Metal Products Div, Hardinge
Operation
K-Tron Corp., (4, 12. 13)
Lake Shore. Inc., (1)
Lively Mlg. & Equipment Co, (1,9,10,12,13)
Logan Corp, (1, 2. 5. 8. 10. 12)
Long-Amta Co. A Dm. ol the Mamvm Group. Inc..
(2.7)
Ludlow-Siytor Wire Cloth. Div. G.S.I.
Manufacturers Equipment Co.. The, (1.2.9.10.
11.12)
Marsh. E. f, Engineering Co.. (1. 9, 10)
Mdjntnan Corp.. (5. 9.10)
UcNaVy Pittsburg Mlg. Corp, (10)
Mineral Services Inc, (4)
Mining Progress, Inc.. (2)
Mwitee/totsmabonal. On. ol Barber-Greene, (1,
10)
Nairn Chemol Co, (3)
NatovtlAf MntorCo, (13)
Natnnaj ton Co.. (1. 10)
National Mnt Service Co.
Nolan Co, The. (6)
Ohman Corp, (4)
Owens Mfg.. Me.. (2. 7)
PettaorwCorp, (1)
Portee, Inc., Pioneer Ore., (1, 5. 9. 10, 13)
Prerser/Mmeco On. Prencr Saenthc Inc, (4.
13)
Ramsey Engineering. Co, (4)
Reed Manufacturing. (12)
Rexnordlnc,(1.2.3.4.5.6.7.8.9.10.11.13)
Reword Inc., Process Machinery Div, (1, 5.13)
Rhh Equipment Co, Material Handling Systems
Div.
Rock Industries Machinery Corp, (1,2, 5,9,10,
13)
Schaffer Poidometer t Machine Co, (4)
Simplicity Engineering, (5, 13)
Solids Flo» Control Corp, (13)
Sprout-Waldran, Koppers Co, Inc, (11.12)
Stamler, W. R, Corp, The, (2. 6, 7)
Stephens-Adamson. (1. 13)
Telsmitfi Div.. Barber-Greene Co, (1. 5. 9. 10.
13)
Thayer Scafe Hyer Industries. (4)
Universal Road Machinery Co, (10)
Vibranetics, Inc, (5. 12.13)
Vibra-Scm Inc. (3. 4. 12, 13)
Waia» Industries Ltd, (5,13)
Webb. Jems B, Co., (1.2.12. 13)
.Webster Mlg. Co, (I. 2. 9, 10)
West \rVginia Belt Sales t Repairs Inc., (1. 2. 5,
13)
Willis & Paul Corp, The. (2. 12)
Wilson, R. M.. Co, (1.5. 8, 9, 10. 13)
FILTER CLOTH, MEDIA
American An Filter Co. Inc.
Ametek
Belleville Wire Cloth Co, Inc.
Dunron Co, Inc, The
Envirotech Coro, Eimco BSP Div.
GAF Corp.
MikroPul Corp.
Mine Safety Appliances Co
National Filter Media Corp.
Pall Corp.
PeabodyABC
Peterson Filters 4 Engineering Co
SmicoCorp.
Unroyal. Inc
Wire Cloth Enterprises, Inc.
FILTER MEDIA, METALLIC
Belleville Wire Cloth Co, Inc.
CE Tyler Inc
Cleveland Wire Cloth & Mlg. Co
Duriron Co, Inc, The
Envirotech Corp, Eimco BSP Div.
Ludlow-Saykx Wire Cloth. On. G.S.I.
Pall Corp
Peterson Filters * Engineering Co.
Wire Cloth Enterprises, Inc.
FILTERS
1. AIR
2 CENTRIFUGAL
3. DISC. DRUM. VACUUM
4. ENGINE & COMPRESSOR INTAKE
5. FUEL & LUBE OILS
6. HORIZONTAL
7. HYDRAULIC FLUIDS
8. WATER
AMFInc.. (1.2. 3, 4, S, 7, 8)
Adams Equipment Co, Inc. (8)
American Air Filter Co, Inc, (1. 2. 4. 6)
Ametek, (2, 3, 6)
HF. a unit ol General Signal. (8)
Bird Machine Co, Inc. (2. 3. 6)
Bowman Distribution. Barnes Group, Inc. (1. 5)
Branlord Vibrator Co, The. Div. ol Electro Me-
dia**. Inc.. (1)
CE Tyler Inc, (1,2)
Caterpillar Tractor Co, (1.4. 5)
Crane, Co, (8)
Cummins Engine Co, Inc, (1,5)
Deron R & 0 Co, Inc, (8)
Donaldson Co, Inc, (1.4)
. Dorr-Oliver Inc, (3)
Dorr Olner Long. Ltd, (3)
Dover Conveyor A Equipment Co, Inc, (I)
Duriron Co, Inc. The, (6)
Eaton Corp, Work) Headquarters. (8)
Enviren. Inc, (3)
Federal Supply & Equipment Co., Inc, (7)
Fer"-T«rti. Inc, (1.2)
hi-1-Vic Corp.. (1.4)
Fleetguard. (4. 7)
Fuller Co A Gab Co, (4)
GAF Corp. (5. 7. 8)
Gardner-Denver Co, (1.4. 5)
General Resource Corp. (1)
HauckMlg Co, (1,5)
Hayden-Nilos Conflow Ltd, (7. 8)
Heil Process Equipment Co, Div. ol Dart Indus-
tries. Inc.. (1. 2)
Huwood-lrwin Co, (7)
Hydreco. A Unit ol General Signal. (7)
Johnson Div. Universal Oil Products. (7. 8)
Johnson-March Corp, The. (I)
Joy Mlg. Co, Denver Equipment Div, (3)
KHO Industneanlagen AG. Humboldt Wedag. (2.
3)
Lively Mlg 4 Equipment Co, (3)
3MCo, (1)
Mathews. Abe W, Engineering Co, (3)
MikroPul Corp.
Mine Salety Appliances Co, (I)
Mining Machine Parts. Inc, (5. 7)
Monitor Mlg Co.(4)
Morgantown Machine & Hydraulics, tnc, Div
Nail. Mine Service Co, (8)
National Environmental Inst Inc, (1)
Norton Co. (8)
Pall Corp. (1.4. 5. 7.8)
Peterson Filters & Engineering Co. (31
Pretser/Mineco Div, Preiser Scientific Inc. (1. 8)
Redding Co, James A, (3)
Research Cottrell. Inc, (1.2)
Sala International. (3)
Schroedei Bros Corp, (7)
Scott Aviation. A Div. ot A-T-0. Inc, (I)
Sry. W. W.MIg Co. (I)
Sperry Vickers On. Sperry Rand Corp . (7)
Spraying Systems Co, (8)
Sprout-WakJron. Koppers Co, Inc. 11)
Stanadyne/Hartlord Div, (5)
Straightline Filters Inc, (3. 6)
Thor Power lorjl Co, (1)
Thurman Scale Co. Div. Thurman Mlg Co. (I)
Unilloc Limited
Union Carbide Corp, (I)
Union Oil Co. ol California. (5)
Varian Associates
WA8CO Fluid Power Div, an American Standard
Co, (1)
Weatherhead Co, The. (2. 5. 7)
Western Precipitation Div, Joy Mlg Co. (1)
Wheelabrator-Frye Inc, Air Pollution Control Div,
(1)
Wiggins Connectors Div. Delaval luitune Inc. (5)
Willson Products Div, £SB. Inc.
Wilson. R. M, Co, (1)
Wire Doth Enterprises, tnc, (I)
Workman Developments. Inc, (3)
FINANCIAL SERVICES
Bache I Co. Inc.
Capital Conservation Group
CIT Corp
Ciluens Fidelity Bank 4 Irusl Co
Oean Witter 4 Co. Inc.
firstmark Morrison Inc.
First National Sank ol Man/land. Energy Re-
sources Div
Manufacturers Hanover Leasing Corp
FIRE ALARMS, DETECTORS
Adams Equipment Co. Inc
Air Urt Inc
A-T.Q Inc
ConracCorp
Fire Protection Supplies Inc.
Hayden-Nikn Condow Ltd.
Jabco, Inc
Kidde. Walter. I Co, Belleville Div
Mine Salety Appliances Co
National Mine Service Co.
Norris Industries. Fire & Salety Equipment On
Preiser/Mineco Oiv, Preiser Scientific Inc
Pyon-Boone, Inc
Red Comet, Inc
Schroeder Bios Corp
Twisto-Wire Fire Systems. Inc.
West Virginia Belt Sales 4 Repairs Inc.
Wilson. R M. Co
FIRE EXTINGUISHERS
1. CHEMICALS. FLUIDS
2. FLUID
3. CO2, DRY-CHEMICAL
Ansul Co, The. (3)
A TO Inc. (1.2. 3)
Big Sandy Electric I Supply Co. Inc. (1. 3)
Bo*.nan Distribution. Barnes Group. Inc . (3)
du Pont de Nemours. E. I. & Co Inc. (1)
Fairmont Supply Co, (1. 3)
Fire Protection Supplies Inc.. (3)
Hayden-Niloi Conflow Ltd, (1. 2. 3)
Kidde. Waiter, I Co, Belleville D», (2. 3)
Logan Corp i3)
3MCo.(l)
Marathon Coal Bit Co. inc. (3)
Michael Walters Ind, (3)
National Foam System Inc.
National Mine Service Co, (1. 3)
Norm Industries, Fire * Safety Equipment On.
• Preiser/Mineco Div, Preiser Scientific Inc . (I)
Red Comet. Inc. (1.2. 3)
FIRE-PROTECTION SYSTEMS
Ansul Co, The
A-T-0 Inc
Austin. J P, Inc
Automatic Sprinkler Corp
Big Sandy Electric & Supply Co. Inc
Cementation Mining Ltd
Fiberglass Resources Corp
Fire Protection Supplies Inc.
Hayden-Nilos Conllow lid.
HiiwoorHrwm Co.
704
-------
Jabco, Inc.
Kiddc, Walter, & Co.. Belleville Div.
Lee Supply Co.. Inc.
3MCo.
Michael Wallers Ind.
Mine Safety Appliances Co.
National Foam System Inc.
National Mine Service Co.
Norm Industries, Fire t Safety Equipment Div.
Persmgers Inc.
Preiser/Mineco On.. Preiser Scientific Inc.
Pyott-Boorw. Inc.
Red Comet, Inc.
S 4 S Macninery Sales, Inc.
Schroeder Bios Corp.
Twisto Wire Fire Systems, Inc.
Uniroyal. Inc.
West Virginia Belt Sales & Repairs Inc.
Wilson. R M. Co.
FLIGHTS, CONVEYOR-LINE
Acco Mining Sales Oiv
Campbell Chain Co.
Cincinnati Mine Machinery Co.
Duquesne Mine Supply Co
E SCO Corp
Fairmont Supply Co.
Hot] Rubber Co.. A Randron Div.
HuwoooMrwin Co
Jeffrey Mining Macninery Div., Dresser Industries
Inc.
Kanavha Mfg. Co.
Laubenstein Mfg Co.
long-Airdox Co A Div of the Marmon Group. Inc
Mining Machine Parts. Inc
National Mine Service Co.
Reinord Inc
Slamler. W. R.Corp., the
Webb, Jervis B. Co.
West Virginia Belt Sales & Repairs Inc
Wilmot Engineering Co.
Wilson. R. M . Co
Workman Developments. Inc.
FLOAT & SINK TEST
SOLUTIONS
American Mmechem Corp.
Preiser/Mmeco Div., Preiser Scientific Inc
FLOAT AND SINK TESTERS
Preiser.'Mmeco Div.. Preiser Scientific Inc
FLOCCULATING AGENTS
Allied Chemical Corp.. Industrial Chemicals D«
American Cyanamid Co., Industrial Chemicals &
Plastics Div.
American Mmechem Corp
Ashland Chemical Co
Bet; Laboratories
Calgon Corp
Cams Chemical Co.
Oowell Div of the Dow Chemical Co.
du Pont de Nemours, £ I & Co Inc.
Goodrich. B F. Chemical Co
Hercules Inc.
Hubmger Co.. The
Nalco Chemical Co.
Preiser/Mineco Oiv.. Preiser Scientific Inc.
Unifloc Limited
FLOTATION CONDITIONERS,
FROTHERS. REAGENTS
Akolac. Inc
American Cyanamid Co. Industrial Chemicals *
Plastics Div
American Mmectiem Corp.
Ashland Chemical Co
BcU laboratories
Calgon Corp
' Ctianne Chemical Co
Daniels Company The
Dowfil D, 01 thf Do» Chemical Co
Heri'ule* l.x
Jo> Mtj{ Co Denver tnuipment Oiv
KHO InOiutriCdnlagen AC. Humboldt W«)jg
PPG Industries. Inc . Chemical Oiv
Preiser -Mmeco Oiv Pieiser Scientific Inc
Shell Chemical Co, Chemical Sales
Unilloc limited
Union Carbide Corp
Wilnioi Engineering Co.
FLOTATION CELLS,
MACHINERY PLANTS
Daniels Company. The
Galiglier Co., The
GEOMIN
Heyl & Patterson, Inc.
Joy Mlg Co. Denver Equipment Div
KHO Induslneanlagcn AG. Humboldt Wedag
lively Mlg & Equipment Co
Sala International
Sala Machine Works Lid
Umlloc Limited
Uniroyal, Inc
WEMCO Div . Envirotech Corp
West Virginia Bell Sales & Repairs inc.
FLOTATION TESTING
Commercial Testing & Engineering Co
Daniels Company. The
Dcmell Div of the Dow Chemical Co
Galigher Co. The
GEOMIN
Haien Research, me
Heyl & Patterson, Inr.
Joy Mlg Co.. Denver Equipment Div
KHD industrieanlagen AG. Humboldl Wedag
Preiser/Mmeco Di». Preiser Sciennlic Inc
Sala International
Unifloc Limited
WEMCO Div . Envirotech Corp
FLOW METERS
Acco. Bristol Div.
American Meter Div , Singer Co.. The
Babcoch & Wilcoi
BIF. a unit of General Signal
Calgon Corp.
Capital Controls Co.
Federal Supply 1 Equipment Co.. Inc
Foiboro Co. The
General Electric Co. Instrument Products Opera-
Inn
Halliburton Services-Research Center
Hayden-Nilos Conflow ltd
Honeywell Inc . Process Control Div.
J-Tec Associates. Inc.
Kay-Ray Inc
Leeds t Northrup Co.
Modern Engineering Co.
National Environmental Inst. Inc.
Pace Transducer Co.. Div of C J. Enterprises
Preiser/Mineco Div.. Preiser Scientific Inc.
Stevens, Inc. C W.
Taylor Instrument Process Control Div Sjrbron
Corp.
Union Carbide Corp.
Unique Products Co
Viking Oil & Machinery Co.
WESMAR Level Monitor Di>.
Westmghouse Electric Corp
FLUID-POWER
COMPONENTS
ADex Corp. Demson Div.
Aeroqutp Corp
Annter Mine 4 Smelter Supply
Arc Corp. the
A-T 0 Inc
Dynex Div. Applied Power Inc
ENERPAC. Oiv of Applied Power Inc
Gu>an Machinery Co
Houghton & Co, E F
Imperial t astman Corp
Imas Industries. Fluid Power Div
National Supply Co. Div. ol Armco Steel Corp
Owatonna Tool Co
Rexnord Inc.
Sperry Vickers Div . Sperry Rand Curp
• Twin Disc. Inc
Weatrerhead Co. The
FREEZEPROOFING ,
CHEMICALS
Allied Chemical Corp. Industrial Chemicals D.«
Celanese Chemical Co
Dowell Div ol the Dow Chemical Co
Hardy Sail Co
International Salt Co
Morton Salt Co
Preiser/Mmeco Div. Preiser Scientific inc
Viking Oil & Machinery Co
FURNACES
1 COAL-ORYING
2 CONSTRUCTION AND PARTS
3 HEAT-TREATING
4 IABORATORY
5 METAL-MELTING
6 PLANT-HEATING
Bigeiow-Uplak-Corp.d. 2)
Campbell. E K Co (6)
Commercial Testing & Engineering Co 14)
Dravo Corp. (1. 6)
Heyl * Patterson. Inc.. (1)
K-G Industries. Inc. (1)
KHD Induilneanlagen AG. Humboldt Wedag. (I.
2. 3. 5. 6)
lecoCorp.(4)
Leeds 4 Northrup Co (3)
Mine 4 Smelter Industries. (3. 4. S)
Preiser/Mmeco Div.. Preiser Scientific inc (4)
Suiltest. inc. (4)
Vanan Associates. (3. 4)
Wall Colmonoy. (3)
Whiting Corp. (3. 5)
Williams Patent Crusher & Pui< Co. 11)
GAGES, LIQUID LEVEL
Alemite & Instrument Div. Stewart Warner Corp
Bibcock & Wikox
Bindicator Co. Div of Improvecon Corp
Crane Co
Foxooro Co. The
Honeywell Inc.. Process Control Div.
Kay-Rai Inc
lunkenheimer Co. Div ol Conval Corp. Sub. ol
Condec Corp
Onmart Corp
Preiser/Mineco Div. Preiser Scientific Inc
Stevens. Inc C W
Texas Nuclear
Unique Products Co
WESMAR level Monitor Oiv
Westmghouse Electric Corp
GAGES. PRESSURE.
VACUUM, FLOW
Acco. Hekoid Gage Div
Adams Equipment Co. Inc.
Alemite & Instrument Div. Stewart-Warner Corp
American Meter Div Singer Co The
Afiixler Mine & Smelter Supply
Beckman instruments. Inc
Duriron Co. Inc.. The
ENERPAC. Div of Applied Power me
Foiboro Co. The
hayden-Nitos Conflow Ltd
Honeywell Inc.. Process Control Di>
Minnesota Automotive Inc
Modern Engineering Co.
'ace Transducer Co. Div ol C.J Enterprises
'reiser/Mineco Div. Preiser Scientific Inc
khroeder Bros Corp
inap On Tools Corp
Templeton. Kenly 4 Co
TOTCO Div Baker Orl Tools me
Westmghouse Electric Corp
GAS DETECTORS, MINE
American Mmechem Corp
A-TO Inc
Bacharach Instrument Co. Mining Div
Bullard E 0 Co
CSE Mine Service Co.
du Pont de Nemours. E I 4 Co Inc
EOmont Wilson Div ol Becton. Dicmnson & Co
Fire Protection Supplies Inc
705
-------
Mine Gas Monitors, Inc
Mine Safety Appliances Co.
National Environmental Inst. Inc
National Mine Service Co.
Pr«iser/Mm«o Div. Preiter Scientific Inc
Scott Aviation A Oiv ol A T-0. Inc.
Witton, R M. Co.
GRIZZLIES
(SEE FEEDERS. GRI2ZLV)
HAULAGES. R.R. CAR,
BARGE. BOAT
ACF Industries. Inc.
Heyl & Patterson. Inc.
Interstate Equipment Corp.
McDowell-Wrtmjn Engrg. Co.'
HEAVY-MEDIUM
RECLAMATION
EQUIPMENT
(SEE MAGNETITE, RECOVER*
SEPARATORS)
HEAVY-MEDIUM
SEPARATORS
/SEE WASHERS. HEAVY-MEDIUM)
HOPPER
OUTLETS-NONPLUGGING
Kalenborn
Solids Flow Control Corp.
WeDb. Jems B. Co.
HOPPERS
Aggregates Equipment Inc.
Bethlehem Steel Corp
Bonded Scale I Machine Co
Concrete Equipment Co.. Inc.
OEMAG Lauchhammer
Dorr Oliver Long, Ltd.
Dover Conveyor & Equipment Co. Inc.
Caston Car 4 Construction Co.
Enterprise Fabricators. Inc.
Fairfield Engineering Co.
Ferro-Tech. Inc.
General Resource Corp.
Hammermills, Inc.. Sub. ol Pettibone Corp.
Hanson. R.A.. Disc.. Ltd.
Industrial Contracting ol Fairmont. Inc.
lively Mlg t Equipment Co
Marsh. E. F.. Engineering Co.
McNally PittsUurg Mis Corp
Rish Equipment Co.. Material Handling Systems
Oiv
Rock Industries Machinery Corp.
Somerset Welding & Steel Inc.
Sprout-Waldron. Koppers Co. Inc
United Mcdll Corp.
Vibra-Screw Inc.
Webster Mlg. Co
. West Virginia Beit Sales & Repairs Inc.
Willis & Paul Corp. The
Wilmot Engineering Co
Wilson. R M.. Co.
HOPPERS, WEIGH
Bethlehem Steel Corp
Concrete Equipment Co. Inc
Connellsulle Corp
Easton Car It Construction Co.
Fairbanks Weighing Oiv. Colt Industries
Fairtield Engineering Co.
General Resource Corp.
Howe Richardson Scale Co.
Railweight. Inc.
Sprout-Waldron. Koppers Co.. Inc
Thayer Scale Hyer Industries
Vibra-Scre* Inc.
Webb. Jems 8. Co
HYDROCYCLONES
(SEE WASHERS, COAL, CYCLONE
WATER)
HYDROSEPARATORS
(SEE WASHERS, COAL)
INSTRUMENTS,
RECORDING, PRESSURE,
TEMPERATURE, ETC.
Acco. BriilcJ Div
Adams Eij'iipment Co. Inc
Alemite 4 instrument Oiv.. Stewart Warner Corp
American Meter Div, Smgor Cc. Ihe
Analytical Measurements. Inc
A-T-0 Inc
Babcrxk 4 rt.lco.
Bacharacn lr,strument Co. Mining Div
Barnes Engineering Co
BecKman Instruments, Inc.
BiddleCo James G
Capital Controls Co
Fisher Controls Co
Foiburo Co. The
General Einclnc Cr, industrial S)ifi Oiv
General Elecl'ic Ci . inslrumenl ProOuLls • >p-rid
lion
Hayden Nilos C.orllr.w LM
Honeywell Inc Procc-jS C&niioi Div
J Tec Associates me
Leeds & Northrup Co
Martmdaie Electric Co
Measurement & Contioi Systems Div. G'lifjn in-
dustries Inc.
National Environmental Insl Inc.
Pace Transducer Co. Oiv. ol C J Enterprises
Preiser/Mmeco Div , Preisei Scientific Inc
Pyolt Boone. Inc
Quest Electronics
Revere Corp ol Amenca. Sub ol Neptune Inll
Corp
Sorle* Co ol North America. Inc
Taylor Instrument Process Control Oiv Synron
Corp
TOTCO Oiv.'Saw Oil Tools, im
Walter NolO Co
WestinghOUSP Elrttrn. Corp
Wilson. R. M.. Co
INSURANCE, CASUALTY,
WORKMEN'S
COMPENSATION
rial Top Insurance To
Old Republic Insurance Co
INSURANCE, PLANT &
EQUIPMENT
Bellelonte Insurance Cos., Sub ol Armco Steel
Corp.
Flat Top Insurance Co.
JIGS
(SEE WASHERS, JIG)
LABORATORY EQUIPMENT
Alnor Instrument Co
Analytical Measurements. Inc
Anixter Mine & Smelter Supply
A-T 0 Inc
Bacharach Instrument Co. Mining Oiv
Bausch I Lomb, SOPD L>v.
Beckman Instruments, Inc
CF Tyler Inc
Commercial Testing t Engineering Co
Davis Instrument Mlg. Co.
Duriron Co.. Inc. The
Fisher Scientific Co.
Galigher Co, The
General Electric Co., Instrument Produds Opera-
tion
General Semitic equipment Co
GenRad
Gilson Screen Co
Hacker Instruments Inc
Joy Mlg Co. Denver Equipment D
-------
Uigeiow-Lipiak Lorp. (t>. t>)
Bonded Scale 4 Machine Co. (3)
Boston Industrial Products Div. American Biltrite
Inc. (3)
Challenge Cook Bros. Inc.. (4)
Cincinnan Rubber Mlg Co.. Oiv ol Stewart-
Warner Coip. (3)
Contractors Warehouse Inc.. (4)
Corharl Reliaclories Co. Div ol Corning Glass
Works. (1.6)
Detnck. M. H.Co.. (1.6)
Dosco Corp. (8)
Dure>Products.Inc..Nail WireClolhDiv.(3.10)
Equipment Mtg Services. Inc.. (7)
ESCO Corp.. (I)
Fairmont Supply Co . (1, 3. 4. 5. 7. 9)
Gather Co. The. (3)
Gates Rubber Co. The. (3. 9)
General Refractories Co. US Reliaclones Div.
(6)
GoodallRubberCo.O)
Goodrich. B F -Engineered Systems Co. (3)
Goodyear Tire & Rubber Co.. (3. 9)
Greenbank Cast Basalt Eng. Co Ltd. (I. b)
Gieengate Industrial Polymers Ltd. (3)
Gntfolyn Co. Inc. (10)
Guyan Machinery Co. (3. 5. 7. 9)
Hanson, R.A. Disc. Ltd.
Hardman Inc. (3. 9)
Neil Process Equipment Co. Div ol Dart Indus-
tries. Inc . (1. 3.9)
Hoi! Rubber Co. A Randron Div. (3, 5)
Himood-lrwin Co. (7)
Industrial Contracting ol Fairmont. Inc. (2)
Iramane Systems. Inc.. (9)
Janes Manufacturing Inc.. (2)
Kalenborn
Kananha Mlg Co I?)
Laubenstem Mlg Co. (2)
LeeSupplyCo.lnc.il)
Lmatfc* Corp. ol America. (3)
3MCo.ll)
North Stole Pyrophillite Co. Inc . (6)
Norton Co (6)
Plastic Techniques. Inc. (10)
Plibrico Company. (5 6)
Poly Hi. Inc. (3. 5. 7. 8 10)
Preiser/Mineco Div.. Preiser Scientific Inc.. (3.9)
RaychemCorp. (10)
Redding Co. James A. (1. 4. 5)'
Republic Steel Corp. (8)
Stonhard. Inc.. (1.4. 5. 7. B. 9)
Thomas Foundries Inc , (2)
Trelleborg Rubber Co . Inc . (3)
Uniroyal Inc. (3)
U S Polymeric. Sub ol Armco Sleel Corp. (10)
Un.iersal Road Machinery Co.. (2. 3)
Waiai Industries I id (3)
Wesi Virginia Bell Sales 4 Repairs Inc. (I, 3. S)
Wilson. R M.Co (1.3. 10)
Workman Developments. Inc . (1. 3 10)
LOADERS. PORTABLE &
SELF-PROPELLED, BELT,
BUCKET
Aggregates Equipment Inc.
Athey Products Corp.
DEMAG Kuchhimmer
Eaton Corp., Forestry & Construction Equipment
Div.
Fairfiett Engineering Co.
Hanson, R.A.. Disc.. Ltd.
Marsh. E. F.. Engineering Co.
Mescher Mtg. Co. Inc.
Mining Equipment Mtg. Corp.
North American 04K
Tiger Equipment & Servian, ltd /O & K Mining
Equipment
Wagner Mining Equip.
W«ujx Industries Ltd.
LOADING BOOMS
1. APRON
2. BELT
3. CHAIN
Dico Co. Inc.. (1)
Dow Conveyor & Equipment Co.. Inc.(2. 3)
ELMAC Corp. (2)
FMC Corp.. Link-Ben Material Kindling Systems
Div.. (2)
FairMd Engineering Co.. (1. 2. 3)
GEC Mechanical Handling Ltd.. (1.2)
Hanson. R.A., Disc.. Ltd.
Heyl & Patterson, IK.. U|
Industrial Contracting of furmonl. Inc.
Jeffrey Mfg Div.. Dmur Industries Inc, (1.2)
Jenkins ol Rettord Ltd., (2)
Lively Mtg t Equipment Co., (1, 2. 3)
McNaHy Rttsburg Mlg. Corp.. (1. 2)
Remord Inc.. (1. 2. 3)
Savage. W. j. Co.. (2)
Stephens Adamson. (2)
Uruttoc Limited
Webb. Jews 8.. Co.. (2, 3)
W*s & Paul Corp.. The. (2, 3)
Wilson. R. M.. Co.. (2)
LOADING EQUIPMENT,
AUTOMATIC. R.R. &
TRUCK
American Pocltin Corp
FairtieM Engineering Co.
Feeco International. Inc
Fuller Co.. A Can Co.
General Resource Corp.
Hanson, R.A.. Disc.. Ltd.
Jenkins ol Rettord ltd.
Lively Mtg I Equipment Co
Matlmn. Abe W, Engineering Co.
McOoweJI-WeHman Engre. Co.
McNtUv PitUburg Mlg Corp
Nolan Co.. The
Rexnordlnc.
Webb. Jems B, Co.
LUBRICATING SYSTEMS
1. CENTRALIZED. CONTINUOUS
2 MANUAL
3 SPRAY. Oil MIST
Adams Equipment Co , Inc.
Aeroquip Corp. (2)
Alemite & Instrument Div. Stevian-Warner Corp
(1.2,3)
Aro Corp. The, (2)
CSE Mine Service Co. (2)
Cypher Co.. The. (1.2)
Oravo Corp, (1, 3)
Dull-Norton Co.. (3)
Eaton Corp. World Headquarters. (1. 2. 3)
Eaton Corp.. Industrial Drives Div., (1, 2. 3)
E Po»er Industries Corp. (1. 2. 3)
Fairmont Supply Co, (1.2. 3)
Gardner-Denver Co, (1, 2)
Iowa Mold Tooling Co.. Inc.
Keystone Div., Pennwalt Corp. (2)
Lincoln St. Louis On. ol McNeil Corp. (1. 2. 3)
Portadrill. Div. ol Smith International Inc.. (3)
Spraying Systems Co
Trabon lubricating Systems, Div. ol Houdaille In-
dustries. Inc.. (1. 2. 3)
TncoMlg Corp.. (1.2. 3)
Wheelabrator-Frye. Inc.. Materials Cleaning Sys-
tems, (2)
Wiggins Connectors Div. Delavai lurbine Inc
LUBRICATORS
I WHEEL. FLANGE
2 JOURNAL-BEARING
3 RAIL
Abe* Corp.. Railroad Products Group. (3)
CSE Mine Service Co. (1.2)
Eaton Corp., Industrial Drives Div.
E Power Industries Corp
Lincoln St Louis Div ol McNeil Corp. (1)
lunkenheimer Co., Div ol Conval Corp. Sub. of
CondecCorp.
Tnco Mtg Corp.. (2)
MAGNETITE
Foote Mineral Co
Haktcmt Co Ml Hope Mine On.
Mineral Services Inc.
Ross Viking Corp. Div. C Rerss Coal Co.
Viking Oil I Machinery Co.
MAGNETITE METERS
MAGNETITE, RECOVERY
SEPARATORS
Dings Co. Magnetic Group
Enei Magnetics
Industrial Pneumatic Systems. Sub ol Industrie!
Contracting ol Fairmont, inc.
Mineral Services Inc.
Sela Machine Works ltd
Stearns Magnetics Inc.. Div. of Magnetics InrJ
Unifloc limited
Wilson. R. M.. Co.
MAGNETS
1. CHUTE & PLATE TYPES
2. DRUM & PULLEY TYPES
3. SUSPENDED
Colt Industries. Crucible, (1)
Dings Co.. Magnetic Group, (I. 2. 3)
Duplex Milli Mtg Co. (1)
Erie! Magnetics. (1.2. 3)
3MCo.
Mineral Services Inc., (1.2. 3)
National Electric Coil Div. ol McGraw-Edison Co..
(3)
Savage. W. J. Co.. (1)
Square D Co.. (1)
Steams Magnetics Inc.. On. ol Magnetics Intl.. (1.
2.3)
Varian Associates
Wilson. R. M.. Co.. (1.2. 3)
MAPS, TOPOGRAPHIC,
PHOTOGRAPHIC
Aenal Surveys. Inc.
Aero Service On.. Western Geophysical Co ol
Amer.
Berger Associates, ltd
GEOMIN
MINE DRAINAGE CONTROL
SYSTEMS
(SEE POLLUTION CONTROL
SYSTEMS)
MOISTURE INDICATORS,
METERS, TESTERS
Acco. Bristol Div
Bacharach Instrument Co Mining Div
Beckman Instruments. Inc
Concrete Equipment Co.. Inc
du Pont de Nemours. E l & Co Inc
Foiboro Co. The
Kay Ray Inc
Preiser/Mineco Div. Preiser Scientific inc
Soittesl. Inc
MOTOR REWINDING,
REPAIR
Atkinson Armature WorVs
Everson Electric Co
FMC Corp, Mining Equipment D»
Flood City Brass I Electric Co
General i kxtric Co. Industrial Sales Oi.
Ciuyan Machinery Co
Hanco International Div of Hannon Electric Co
Joy Mlg Co
Joy Service Center. Div Joy Mlg Co
louis Alus Div. Litton Industrial Products, inc
National Electric Col Div ol McGra»-F.dison Co
Pennsylvania Flectnc Col. Inc
Reliance Electric Co
S & S Machinery Sales, inc
Wesi Virginia Armalure Co
Westinghouse Electric Corp
MOTORS
1 AC
707
-------
i AIH
3. DC .
4. FLUID, HYDRAULIC
GEAH-(SEE GEARM010RS)
Al»i Corp. Onison Or., (4)
Acme Machinery Co. (2)
Adlim Equipment Co. ln<. (I)
Allis Chalmers. (1.3)
American Pociai'i Cotp. (4)
trailer Mine 4 Smeller Supply. (I. 2. J, 4)
Aro Corp . Th«. (2)
ASEAInc, (I 3)
Big Sandy Electric 4 Supply Co. Inc
8ro»nmg Mfg On., Emerson Electric Co.. (1. 3)
Chicago Pneumatic Equipment Co. (2)
Commercial Shoring. Inc.. (4)
Complex! Electrical Equipment Corp., (1,2)
Comae Corp. (I. 3)
Continental Conveyor It Equipment Co.. (1)
Ddavan Mfg Co.. (4)
Data Conveyor 4 Equipment Co.. Inc. (I. 3)
Oynei On.. Applied Power Inc.. (4)
Eaton Corp. World Headquarters, (1. 3. 4)
Elton Corp.. Industrial Drives On. (1.3)
Eimo> Mining Machinery. Envirotech Corp, (2)
Electric Machinery Mfg. Co. (I)
Electric Products On.. Portec Inc.. (1)
FMC Corp. Mining Equipment Div.. (1.3)
Fairmont Supply Co.. (1.3)
Fenner, J H. & Co, ltd., (I, 2, 3)
Fidelity Electric Co Inc.. (3)
Gardner-Denver Co., (2)
General Electric Co.. DC Motor & Generator
Dept, (3)
General Electric Co.. Industrial Sales Oiv, (I. 3)
Gould Inc. Century Electric On., (1,3)
Hamischteger Corp.
Hydraulic Product! Inc.. (4)
Hydreco, * Unit ol General Signal. (4)
rnienoll-Rand Co., (2)
Jeffrey Minng Machinery Oiv.. Oress«r Industries
lnc.,(l)
Joy Mil, Co. (2)
Joy Sennet Center. Oiv. Joy Mlg Co.. (1. 3. 4)
K»sey Mfg Co, (3)
Lawnd Corp., (3)
lee Supply Co, Inc.. (1.2. 3)
Una Electric Co, Inc. (I)
Lino* Electric Co., The
Lincoln SL Louis On. ol McNeil Corp.. (2)
Logan Corp.. (1.3)
Louis Mlrs On, Litton Industrial Products. Inc. (1,
3)
Lucas Industries. Fluid Power Div, (4)
Micro Switch, A Div. ol Honeywell, (3)
Mining Progress, Inc. (1.2.4)
Morse Chain. Oiv of Borg-Warner Corp.. (1.3)
Mosebach Manufacturing Co
National Mine Service Co.. (1.2)
Norm American Hydraubcs. Inc. (4)
Pennsylvania Electric Coil. Inc.. (1.3)
Porter. HK Co, Inc.. (1. 2. 3)
Preitrjl.lt Electrical Orv. ol Ellra Corp, (I. 3)
Reliance Electric Co.. (I. 3)
Re«nordlnc,,(4)
Romcon Corp. (1.3)
Soerry Vickers Oiv.. Sperry Rand Corp.. (4)
Sterling Power Systems, Inc, A SuD. ol The Lionel
Corp (1)
Thor Power Tool Co.. (2)
U. S Electrical Motors On Emerson Electric Co..
(1.3)
West Virginia Armature Co.. (1. 3. 4)
Wtshnghouse Electric Corp , (1.3)
Wilson. R M.. Co.. (1.2. 3 4)
NOZZLES. FOG
A 1O Inc
Bete Fog Noule. Inc.
DeUvan Mlg Co
FMC Corp.. Agricultural Machinery Div.
Fire Protection Supplies Inc
Goodall Rubber Co.
Harm Industries, Mme & Mill Specialties
Industrial Rubber Products Co.
Mining Progress, Inc.
National Mine Sena Co.
Pmser/Mncco On. Preiser Scientific Inc.
Some Oevdooment Corp
Spraymg Systems Co.
Vr»«ig Oil 4 Machinery Co
Workman Developments. Inc
NOZZLES, SPRAY
Acco Mining Sales Div.
Adams Equipment Co, Inc
Aro Corp, The
A-TO Inc
Self Fog Noiite, Inc
Big Sandy Electric 4 Supply Co Inc
Bowman Distribution. Barnes Group. Inc
Dtister Concentrator Co Inc, lh«
Dtfaian Mlg Co
FMC Corp. Agricultural Machinery Ov
fanmonl Supply Co
fire Protection Supplies Inc
General Electric Co. Carbotoy Systems Oept.
GooUall Rubber Co
Hahn Industries. Mine 4 Mill Speciallies
Hayden-Nitos Conflow Ltd.
Industrial Pneumatic Systems. Sub of Industrial
Contracting ot Fairmont, me
Industrial Rubber Products Co
Johnson March Corp.. The
Krebs Engineers
lee Supply Co.. Inc.
Lincoln St. Louis On ol McNeil Corp.
Logan Corp
Mining Progress, Inc.
National Mine Service Co.
Preiser/Mineco Div.. Preiser Scientific Inc.
Reinord Inc.
Sonic Development Corp
Spraying Systems Co
Umroyal. Inc.
Viking Oil 4 Machinery Co.
Workman Developments, Inc
NOZZLES. WET ROCK
DUSTING
Bete Fog Nonle. Inc.
DeU.an Mfg. Co
General Electric Co., Carbotoy Systems Dtpt
Industrial Pneumatic Systems. Sub of Industrial
Contracting of Fairmont, (nc
Norton Co.
Sonic Development Corp
Spraying Systems Co.
Workman Developments, Inc.
PANELS & PANELBOAROS,
INSTRUMENTS, CONTROL
Acco. Electro-Mech Oiv
Aggregates Equipment Inc.
Allen-Bradley Co.
Anuter Mine & Smelter Supply
Bacharach Instrument Co Mining Div
Beckman Instruments, Inc '
Cam-Lok Div., Empire Products, Inc.
Communication & Control Eng Co Lid
Compton Electrical Equipment Corp
Concrete Equipment Co., Inc
Crouse-Hinds Co.
Cutler-Hammer, Inc
Fairfield Engineering Co
Fairmont Supply Co.
Foiboro Co.. The
GTE Sylvama Inc.
General Electric Co., Industrial Sales Div
General Resource Corp.
Guyan Machinery Co.
Hanco International Div. ol Hannon Electric Co.
HB Electrical Mlg Co
Honeywell Inc, Process Control OK
I-T-E Imperial Corp.
Leeds 4 Northrup Co
Louis Allis Div.. Litton Industrial Products. Inc.
Preiser/Mineco Div., Preiser Scientilic Inc
Pyott-Boone. Inc
Seton Name Plate Corp.
Square 0 Co,
TOTCO D.v Baker Oil Tools, Inc,
Webb. Jems B. Co
Westmghouse Electric Corp
PH INDICATORS,
RECORDERS
Acco. Bristol Div
Analytical Measurements. Inc
Babcock 4 Wiicoi
Beckman Instruments, Inc
Bet/ Laboratories
CS£ Mine Service Co
Eiexlrolacl
Kisher Scientilic Co
Foiitwro Co. The
Great Lakes Instruments. Inc
Leeds t NortlirupCo.
Perkin-Elmer Corp.
Preiser/Mmeco Oiv. Preiser Scientific Inc
Soiltal. Inr
PIPE
I AIIIMINUM
1 ALUMINUM MAS IIC
3 At UMINUM. STEAM TRACED
4 ASHtblOS-CEMINT
5 BRONZt, COPPER. WED BRASS
6 CAS1 IRON WROUGHT IRON
7. IINED
8 CORFKJSION RESISTANT
9. CORRUGATED
10. DRIVE & DRIVING WINCHES
11 PLASTIC
12 RUBBER
13 RUBBER-LINED
14 SEAMLESS
1 5 SPIRAL WELDED
16 STAINLESS STEEL
17 STEEL. STEEL WELDED
18 STEEL. PLASTIC COATED
19. WOOD. WOOD-STAVE
20 GLASS FIBER REINFORCED
Acker Drill Co. Inc. (10)
Alcoa. (I. 3. 14)
Allegheny Ludlum Steel Corp (8. 14. 16. 17)
Ampco Metal Div.. Ampco Pittsburgh Corp. (S.
8)
Aniiter Mine & Smelter Supply. (8. 11. 20)
Armco Steel Corp. .Product Info. (7.8.9. 11.14.
16)
Barxock S Wilcoi (8. 14. 16. 17)
Bethlehem Steel Corp. (9 14 17. 181
CF & I Steel Corp. 114)
CalwisCo.dl)
Capital City Industrial Supply Co
•Certain Teed Prwucu Corp., Pipe 4 Pasi.cs
Group. (4. II)
CIBAGEIGY Corp, Pipe Systems Oept. (8. 20)
Cincinnati Rubber Mfg Co. Oiv. ol Stewart
Warner Corp. (12)
Coll Industries, Crucible. (6, 16)
Continental Rubber Works. Sub ol Conlmenul
Copper & St«el Industncv Inc., (12)
Contractors Warehouse Inc.. (15. 17)
Oetricli.M H,Co.(7. 8)
du Pont oe Nemours. E. I. & Co Inc , (11)
Dunron Co. Inc. The. (8)
ESCO Corp. (6. 8. 16)
Fairmont Supply Co, (11. 12. 13. 14. IS, 20)
Federal-Mogul Corp, (II)
Fiberglass Resource! Corp. (8. ID
Fk«oleValveCorp.(l2)
Foster. L. B. Co., (6. 7. 14. IS, 17)
Gahgher Co. The. (7. 8. 13)
Gates Rubber Co. The. (13)
General Resource Corp., (1, 6. 8)
General Scientilic Equipment Co.. (I I. 12)
Goodall Rubber Co. (11. 12)
Goodricn. B. F -engineered Systems Co. (13)
Goudyear Tire & Rubber Co.. (12. 13)
GreenbanK Cast Basalt Eng Co Ltd.. (7. 81
Greengate Industrial Polymers Ltd., (12)
Gnndei CWI Distributing Co, (15, 17)
Hal Process Equipment Co. Oiv ot Dart Indus-
tries. Inc. (8. II. 16)
Hercules Inc. (8)
ITrGnnnellCorp.dl. 14. IS)
ITT Harper, (16)
Irathane Systems. Inc. (13)
Jennmar Corp.
Johnston Moretnuse Dickey Co. (11)
Jones 4 Laughbn Steel Corp.. (14.17)
Kaiser Aluminum 4 Chemical Corp. (I)
Kalenborn. (7. 8. 12)
Kinelics. Inc. (8)
Lee Supply Co. Inc. (1.2.9,11.13.14.15.16.
18. 20)
Lmaten Corp of America. (13)
Logan Corp. (11. 17)
Midland Pipe 4 Supply Co.. (1. 8. 13. 16)
National Mine Service Co, (2. 11)
Naytor Pipe Co.. (13. 15. 16)
PeabodyABC. (11)
Phelps Dodge industries. Inc. (5. B)
Phillips Products Co., Inc, (11)
Preiser/MinecoDiv. Preiser Scientific Inc. (11)
Red Valve Co, Inc, (12)
Republic Steel Corp. (8. 9. 14. 16. 17. 18)
Reynolds Metals Co. (I, 3)
Rubber Engineering & Mfg Co. (12. 13)
708
-------
Ftyerson. Joseph T.,&Son.lnc..(l,8,11. 14, 16.
17)
Smith, . 0 Inland Inc. Reinforced Plastics Div,
(8. 11.20)
Slellite Oiv.. Cabot Corp.. (8)
Trelleborg Rubber Co., Inc.. (12)
Tricon Metals & Services. Inc., (8, 11. 14, 16,
17)
Tube Turns Oiv., Chemetron Piping Systems.
(17)
Union Carbide Corp., (8)
Uniroyal. IncT. (12)
United McGill Corp.. (1, 11, IS)
United States Steel Corp.(1,7.8,9,11,14,16.
17. 18)
Valley Steel Products Co.
West Virginia Belt Sales & Repairs Inc., (11. 12.
13)
Whmaker Corp., (6. 7, 8. 14, 17)
Wilson. R. M.. Co.. (2. 8. 20)
Workman Developments, Inc., (8. 11)
youngstown Sheet & Tube Co.. The, (8. 11, 14.
17)
PIPE ACCESSORIES
1. COUPLINGS
2. COUPLINGS. FLEXIBLE
3. COUPLINGS. GROOVED
4 COVERINGS
5. FITTINGS. BRASS & BRONZE
6 FITTINGS. CAST-IRON
7 FITTINGS. MALLEABLE-IRON
8 FITTINGS.
FLANGES-FABRICATION.
WELDING
9. FITTINGS. FORGED STEEL
10. FITTINGS. PLASTIC
11. FITTINGS. RUBBER
12. FITTINGS. STAINLESS STEEL
13. FLANGES, FORGED, STAINLESS.
ALLOY
14 GROOVERS
15. HANGERS
16. REPAIR CLAMPS. SLEEVES
1 7. FITTINGS. CAST STEEL
Acker Drill Co.. Inc.. (1)
Adams Equipment Co , Inc., (1, 5. 12)
Aeroquip Corp. (1.2. 8. 9)
Ampco Metal Div, Ampco-Pittsburgh Corp. (5)
Anchor Coupling Co. Inc.. (!, 5. 7, 8, 9)
Anitter Mine & Smeller Supply. (14)
A-TO Inc.d. 5. 15)
Bibcock &Wilco«. (8, 12)
Bethlehem Steel Corp. (9, 13)
8-g Sandy Electric & Supply Co.. Inc.. (3, 6. 7)
Bowman Distribution. 8ames Group. Inc , (1,6.
7)
' C F 4 I Sleel Corp.. (1)
Campt«:i Cr.a.r> Co. ilii
Cf-fljir.-Teto Prodocts Corp. Pipy A Plastics
Croup (I. 10)
Clayton Mam-Pacific Vaues. Div of Mark Con-
trols Corp. (11
Continental Rubber Wonts. Sub of Continental
Copper & Sleel Industries. Inc.. (11)
Contractors Warehouse Inc . (1. 3)
Oresser Manufacturing. Div Dresser Industries.
inc. (1.2, 5. 7. 10. 16)
du Pont rje Nemours. E I A Co. Inc . (10)
Dunron Co, Inc . The. (1.6)
ESCOCorp.(8. 10. 12. 13)
Fairbanks Co. The. (7)
Fairmont Supply Co.. (1 3. 6. 7, 8 9. 10. 15.
161
Fastener House. Inc . (15)
Federal Mogul Corp (10)
Fiberglass Resources Corp.(1. 10. '.o|
FlexDIe VaUe Corp .(II)
foster i B LO (1)
Genei.i' Resource Corp . (I)
Goodoii Rubber Co. (i 0 II)
Grecntunk Cast Bjsail Eng Co tta (1 rt lb)
Giistin Bacon Di. Aeroquip Corp . (1 36/9,
12. 141
•:~i Gr.nne;iC»p (i 2 b.6. 7.8 9 10 1.' 1 3
15 17)
in Mo'uD industries (151
imperial-Eastman Cap, (1, 5 10)
' 'ndusln.ii Rut-Der Products Co .(10. 11 i i. 13)
.•wnston-Morehouse-Dickey Co. (1. 3 10)
Jow I laagniin Steel Corp
LaoishQj (1 8 9. 12. 13)
tee Supply Co Inc (1 3 6 7 10. 14. li 16.
:7)
le Hi valve A Courjirnj; Hose Products 0 • r'jrk
fr Hirr..ti.i Cor|) (1. 3. 5 6 ' 9 10 ('!.)
Midland hpt 4 Supply Co. (8. 12. 111'
National Mine Service Co. (1. 3)
Naylor Pipe Co. (8. 12)
Ohio Brass Co. (7. 15)
Parker-Hanmlin Corp. Tube Fillings [)iv . (b. 1
12)
Phelps Oodgc Industries. Inc ,(1.4 5. 8)
Phillips Products Co. Inc. (10)
Plymouth Rubber Co Inc . (4)
Preiser/Mmeco Div , Preiser Scientific Inc. (I.
10)
Red Valve Co.. Inc., (2. 11)
Seton Name Plate Corp.. (4)
Smith, A. 0 Inland Inc. Remfurced Plastics Div.
(10)
Spraying Systems Co.. (5)
Stralollei. Inc., (I 5. 8. 12. 13)
Thor Power Tool Co. (I)
Trelleboig Rubber Co.inc (1)
lube Turns Div, Chemelror P.p-Y 'i)S!i?inj ih
9 12 13)
United Stales Steel Corp . (1. 2. 3. 6 7. it. 9. 12
13 14 16)
Valley bteel Products CD
Viclauiir Co of America. (1. 2. 3 6 7. !? M
16)
Wactis. E H. Co.
Weathcrhead Co. The. (1. b 9. 12!
West Virginia Bell Sales & Repairs Inc. 11. 10)
Wiggins Connectors Div Delaval Turbine Inc. (2)
Wilson. R. M.Co. (1. 10)
Workman Developments, Inc.. (1. 10. 16)
PIPE FABRICATION,
WELDING
American Alloy Steel, ln>.
Ampco Metal L"v Ampco iMtsbi.rgri Cr.'ip
Diavo Corp
Foster. L B, Co
Greenbank Cast Basalt Eng Co Lid
Lively Mfg. & L'quipmenl Co
Mclaughlin Mlg Co
Midland Pipe & Supply Co
Rubber Engineering & Mlg Co
Slearns Roger Inc.
Valley Steel Products Co
Wachs, E H. Co
Workman Developments. Inc.
POLLUTION CONTROL
SYSTEMS
1 ACID MINF DRAINAGE
2 SOLIDS KEMOVAI FROM WATER
3. DUSI & KIMf-
Aerofall Mills ltd (3)
Aggregates Equipment Inc.. (3)
An Correction Div. UOP. (31
An Pollution Control Operations FMC Corp . (3)
American Air Filler Co. Inc . (3)
American Alloy Steel. Inc. (1. 2. 3)
American Meter Div , Singer Co The. (I)
American Standard, industrial PicUuctsCiv ."(3)
A-T-0 Inc.
Badger Construction Co Div of Mellon-Sluarl
Co,(l 2. 3)
Bell Laboratories. (2)
Bigelow-liptak Corp |3)
Bird Machine Co . Inc . (2)
Calgon Corp. (2)
Conwed Corp Environmental Products Div
Crane Co.
Davis Instrument Mlg. Co. (3)
Dorr Oliver Long. Ltd. (1. 2)
Do*ell Oiv of the Do» Chemical Co (1. 2. 3)
DravoCorp. (1. 2. 3)
Di/con Co.. Inc. The. (3)
Eatun Corp. Industrial Drives Di», (?)
Environmental Equip Div. CMC Corp (2. 3)
Envirotech Corp , Eimco 8SP Div. (1. ?)
trie; Magnetics. (2)
Fairbanks Morse Engine Div. Colt Indu: tries (2)
ler.o-Tech. Inc.d. 2. 3)
F iberclass Resources Corp
Finn Equipment Co
fuller Co A Gau Co. (3)
General Resource Corp . (3)
Mayden Nitos Confk>» IM. (3)
Heil Process Equipment Co. Di« ol Dart indus-
tries Inc (1.2. 3)
Hundrick Mfg Co . (1)
Heyl & Patterson Inc.d. 2, 3)
Holley. Kenney. Sihott, Inc, (I. 2. 3)
industrial Conlrailing ol Fairmonl, Inc . (1. 2. 3)
industrial Pneumatic Systems, Sub ol irtdusinal
Contraciint; ol Fairmont Inc. (1.2 3)
Jeffrey Mlg Di>, Dresser industr.es Inc. 12)
Johnson-Marcn Corp. The. (3)
Joy Mlg Co. Denver Equipment Div
Kay Ray Inc. (2)
Koch Engineenng Co. Inc (31
KoppersCo.lnc.d. 2. 3)
Krebs Engineers. (3)
lively Mlg & Equipment Co (1. 3)
. McDo«eil Weilman Engrg Co (31
McNally Pillsburg Mlg Corp . (2)
MikroPul Corp.. (3)
Mining Equipment Co A Unit ot General Signal,
(1)
Molt.B H, iSons Inc.C)
Naico Chemical Co. (1. 2)
National Car Rental Systems >nc MuJcat Div,
(2)
Norton Co.. (3)
Numoriics Corp
NUS Corp , Robinson 4 Robinson Div (1.2.3)
Parkson Corp .(1.2)
Peterson Filters & Engineering Co . (2)
F-ruser/Mineco Oiv . Preiser Sc.enlilic Inc. (1. 3)
Reed Manufacturing, (3)
Research Cornell Inc. (3)
Reinoro Inc. (1. 2)
Said International, (2)
Sauerman Bros.. Inc. (2)
Shirley Machine Co. Oiv Tasa Corp.. (!)
Tteadwell Corp.
' Trelteborg Rubber Co, Inc. (3)
Umlloc Limited
Union Carbide Corp (2)
United McGillCoip. (3)
Wf MCO Div. Envirotech Corp. (2)
Western Precipitation Div.. Joy Mfg Co. (3)
Wtstinghouse Electric Corp. (1, 2 3)
Wheelabrator-Frye Inc. Air Pollution Control Div.
(3)
Willis & Paul Corp. The (3)
PREPARATION - PLANT
BUILDERS
Alien & Garcia Co
Badger Construction Co. Di« of Melioi Stuart
Co
Daniels Company The
Oravo Corp
FMC Corp. unk Beit Material Handling Systems
Du
Fairtitld Engineering Co
C-EOMIN
Head Wr.ghtson & Co ltd
Heyi & Patterson. Inc.
Hollpy. Kenney Scholl. Inc
Industrial Contracting ol Fairmont Inc
Jeffrey Mtg Div . Dresser fnoustr*s Inc
ienkms ol Retlord ltd
KHD Industrieanlagen AG. Humboirji Weoag
Lively Mlg & Equipment Co
long Aifdoi Co A Div. of the Marmon Grouu me
McNaily Piltsburg Mlg Corp
Minerals Processing Co. Dtv of Troian Steei Co
Pullman Torkelson Co
Rish tujupmeni Co. Material Handling bysiems
OfV
Roberts & Scnaeler Co
Roller Corp
Unifloc Lim.ted
WJmot Engineering Co
PREPARATION PLANTS,
PORTABLE
GFOMIN
Heyl & Patterson Inc
Industrial Contracting of Fairmont Inc
jenMisol Retlord ltd
' lively Mfg & Equipment Co
Mmtei international. Div of Barber Greem:
Saia international
Unifloc Limited
Wilmct h^ineering Co
Wilson R M.Co
PULVERIZERS
1. COAl
2 FURNACE-FEED
3 I.ABORATUHY
709
-------
Aerofall Mills Ltd, (1. 2. 3)
Amenun Pulverizer Co. (I)
Annltr Mine & Smelter Supply, (3)
British Jttlrey Diamond. Div. ol Dresser Europe
5.A (UK. Branch). (1.3)
C-E Power Systems, Combustion Eng, Inc. (I)
C-E Raymond/Bartlett-Snow. Uiv. Combustion
Ehfjineenng. Inc.. (1.2. 3)
GEC Mechanical Handling ltd., (1)
Gruendler Crusher I Purveruer Co.. (1. 2. 3)
Hammermills. Inc.. Sub. ol Pettibone Corp., (I)
Hewitt-Rooms D«.. litton Systems. Inc.. (1)
Holmes Bros Inc.. (3)
Jeffrey Mfg Div.. Dresser Induslnes Inc.. (I)
KG Industries, Inc.
KHD industrieanlagen AG. Humtxildt Wedag. (I.
3)
Kennedy Van Saun Corp. Sub ot McNally Pins-
burg. (1)
• KoppersCo.. inc.. (1)
Maiac Div.. Donaldson Co (1)
Mine 4 Smelter Industries. (3)
Morse Bros. Maclnnery Co. (3)
Preisei/Mimxo Di«., Preiser Scientific Inc.. (3)
Pulventmg Machinery. Oiv. ol MikioPul Corp.. (1,
3)
Sodtest. Inc. (3)
Stedman Fdy. 4 Mach. Co.. (1.3)
Steel Meddle Mlg. Co. Industrial Div, (1) .
Slurtevanl MiH Co. (3)
Williams Patent Crusher & Pulv Co.. (I. 2. 3)
.Wrbon, fl. M, Co, (1.2. 3)
Workman Developments. Inc.. (3)
PUMP LININGS
Amsco Div, Abu Corp
Equipment Mltf Services. Inc
Fairmont Supply Co.
Gaiigher Co, The .
Holi Rubber Co, A Randron Div
Linatei Corp ot America
RM Roll Products Co.. Div. Raybeslos-Manhattan,
Inc.
Stonhard, Inc.
West Virginia Bel! Sales & Repairs Inc.
PUMPS
1 CENTRIFUGAL
2. CORROSION • RESISTANT
3. DIAPHRAGM
4. DRUM
5. FROTH-HANDLING
6 METERING
7. PISTON & PLUNGER
8 PRESSURE-TESTING
9. PRIMING
10. SAND & ABRASIVE HANDLING
11. SLURRY. SOLIDS-HANDLING
12. SUBMERSIBLE
13 SUMP
14. TRANSFER
15. TRASH & SLUDGE
16. VERTICAL CENTRIFUGAL &
TURBINE
17. POWER HYDRAULIC
18. EXPLOSIONPROOF
AMHnc.13. 6. 7)
A-S H Pump. Div ot Envitotech Corp. (1. 2. 10.
II. 13. 16)
Al£i Corp. Denison Div, (1 /)
Acker Drill Co. Inc,(7)
Adams Equipment Co. Inc , (1. 2. 7)
Alemite & Instrument Div. Stewart-Warner Corp..
(2 .4,14)
Allis-Chalmers, (1.2. 10. II 12. IS. 16)
American Crucible Products Do. II, 12. 13)
Ampco Metal Div.. Ampcrj Pittsburgh Corp, (1,
2)
Amsco Div.. Abei Corp.. (2. 10. 11. 15)
Anderson Electric Corp., (17)
Arc Corp The. (4. 6. 7. 14)
Atlas Copco. Inc.. (1. 3)
Aurora Pump. Unit of General Signal. (1. 2. 13.
16)
Barren. Haentiens Co. (1. 2. 5. 9. 10, 11, 12,
13. 16)
Beckman Instruments. Inc.. (6)
BIF, a unit of General Signal. (3. 6, 7)
Byron Jackson Pump Div., Borg Warner Corp. (1.
2. 12. 13. 14. 16)
Calgon Corp.. (2. 3. 6, 7. H)
Canton Stoker Corp.. (2. 7, 10.11, 14. IS, 18)
Larwmnmum company'
Carver Pump Co., (1.2, 3. 8.9.10.11.13.14.
15. 16)
Chicago Pneumatic Equipment Co.. (12.13. 15)
CompAn Construction & Mining ltd.. (1. 12. 13.
15)
Contractors Warehouse Inc.. (10. 11, 12. 13.
IS. 18)
Dane Co. (1.2 3.4.5.6.7.8.9.10. II. 12.
13. 14. 15. 16)
Crisafulli Pump Co. Inc.. (!. 11,12.13.15,16.
17. 18)
Dean Brothers Pumps. Inc.. (1. 2, 14. 16. 18)
-Dorr-diver Inc. (1.2, 3. 11)
Dorr diver Ions. Ltd.. (1.2. 3. 11)
Dresser Mining Services & Equipment Div., (3. 7)
Duff-Norton Co, (17)
DunronCo, Inc. The. (1.2. 3. 9. 16)
Dynen Div., Applied Power Inc.. (17)
FNERPAC. Div ol Applied Poww Inc., (7. 8)
English Drilling Equipment Co Ltd.. (7)
Environmental Equip. Div, FMC Corp.. (1.11.12.
13. 14. IS. 16)
E Power Industries Corp. (14)
FMC Corp., Agricultural Machinery Div., (2, 7. 8.
14)
FMC Corp.. Pumpftv.. (I, 2. 12. 13, 14. 16)
Federal Supply & Equipment Co, Inc, (8. 17)
Fire Protection Supplies Inc., (I. 3. 9, IS)
Flood City Brass & Electric Co. (1, 2. 7)
Flygt Corp.. (2. 10. 11. 12. 13, 15. 18)
Fuller Co, A Gain Co. (1. 10. 18)
GEC Mechanical Handling Ltd. (1.2,10,11,13.
16)
GaligherCo, The. (1,2. 5. 10. 11/13. 14)
Gardner Denver Co. (2, 3. 7, 8, 11.12. 13. 14.
18)
General Scientific Equipment Co, (4)
Gorman-Rupp Co, The, (1,2.3.6,9.11.12.13.
14. 15)
Goulds Pumps. Inc. (1.2,9, II. 12.13.14.16.
18)
GoynePumpCo, (1,2, 10. 11. 13, 16)
Grmdex-CWI Distributing Co. (10. 12. 13. 15.
18)
Gulf Oil Corp. Dept DM
Gullick Oobson Intl Ltd, (I)
Guyan Machinery Co, (1.2,3, 7.10.11.12.13.
15)
Hardman Inc, (6)
Homelite Div, Textron Inc, (1. 3. 12. 15)
Hulburt Oil & Grease Co, (4)
Huwood-lrwin Co, (17. 18)
Hydraulic Products Inc, (17)
Hydreco, A Unit ot General Signal, (17)
Hydr-0-Matic Pump Div.. Weil-McLain Co, Inc.,
Claremont 4 Baney. (1.3. 9. II. 12. 13)
Industrial Rubber Products Co., (1,3,4.7,9,12,
13. 14, 15. 16. 18)
lngersoll-RandCo,(1.2. 7.10. II. 12.13.14.
IS. 16)
Jaeger Machine Co, (1. 3, IS)
Jennmar Corp
Johnston Pump Co, (2. 12. 13. 14. 16. 18)
Johnston Pump Co, Pittsburgh Branch. (2. 12.
13. 14, 16)
Joy Mfg Co.. Denver Equipment Div, (1. 2. 3. 5.
6.10.11.13.16)
Joy Mlg. Co. (U.K)Ltd, (11)
KHD Industrieanlagen AG. Humboktt Wedag. (I.
10. II. 13. 18)
LaBour Pump Co, (1.2. 5. 9, II. 13. 14. 16.
18)
Lawrence Pumps. Inc, (1. 2. 9. 10. 11. 13. 14.
16)
Lee Supply Co. Inc. (1.2. 3. 7.11.12. 13. 14.
IS. 16. 18)
Le Hoi Div, Dresser Industries. Inc, (3, 12, 13)
Lightning Industries, Inc, (2. 10. II)
LinatoCorp of America. (1. 10. 11. 13)
Lincoln St. Louis Div. ol McNeil Corp, (2. 4, 7.
14)
Logan Corp, (11. 12. 15, 16)
Lucas Industries, Fluid Power Div, (17)
McNally Pittsburg Mlg Corp, (1)
Megator Corp, (3. 6, 9. 13. 14)
Midland Pump. LFE Fluids Control Oiv, (1, 2. 3.
10. 11. 12. 13. 15)
Mineral Services Inc, (I. 10. 11.13)
Mining Developments Ltd, (13)
Mining Progress Inc, (7)
Minnesota Automotive Inc, (1. 14)
Morris Pumps, Inc. (1.2. 5,10. II. 12.13.14.
15. 16)
Nagle Pumps. Inc:. (1. 2.9. 10.11,12.13. 16)
Nash Engineering Co.. (9)
National Car Rental Systems Ira.., Mudcat Div,
(ID
National Environmental Inst. Inc, (2)
National Supply Co Oiv of Armco Steel Corp. (7.
17)
Peabody Barnes. (1,2. 3,7. 9. 10. II. 12. 13.
14, 15)
Pettibone Corp. (10. 11)
Porter, H K, Inc. (17)
Porto Pump. Inc, (8)
Preiser/Mineco Div . Preiser Scientific Inc . (1. 2.
3. 4. 6. 7)
ProsserIndustries.Div olPureiCorp.d. 3.12.
13)
Rnnordlnc.d?)
Robbins I Myers. Inc, (2. b. 6. 9. 10. 11. 14.
15)
SalaInternational. (1. 2. 5,10. II. 13. 16)
Sala Machine Works Ltd. (1.2. 5. 11. 13 161
Soerry Vickers Div . Spetry Rand Corp ,(17)
Sprague & Henwrxx). Inc, (7)
. Stanarjyne/Hanlord Div. (7. 14)
Stance Mlg. & Sales Inc.. (1. 2.10, 11. 12 15.
18)
Sundslrand Fluid Handling. Div Sundslrand
Corp. (1.2. 8. 14. 17. 18)
T4TMachineCo,mc..d.2.3. 7.9.10.11.12
13. 15. 16. 18)
Tiber Pump Co.. Inc.. (1,2,11. 13. 14. 16. 18)
Templeton. Kenly & Co, (17)
Thomas Foundries Inc. (1, 10. 11. 15)
Thor Power Tool Co.. (11, 12, 13)
TRW Mission Mlg Co, Div. of TRW Inc, (1)
Unilloc Limited
Union Carbide Corp. (1,2)
United Stales Steel Corp.
Valley Steel Products Co, (12. 16)
Viking Oil & Machinery Co, (5,' 14)
Wachs.E H.Co.(l2. 17)
Waiai Industries Ltd, (1. 3. 7. 10. 11. 12. 13.
16)
Warman International. Inc, (I, 2. 5. 10. II)
Warren Rupo Co. the. (I. 2. 3. 6. 7.9. 10 II.
12. 13, 14. 15 18)
WEMCO Oiv, Envirotech Corp. (1. 2. 5. 10. 11.
12. 13. 14. 15)
West Virginia Armature Co, (11. 13)
West Virginia Belt Sales 4 Repair! Inc, (1. 2. 7.
10. 12. 13)
Wilfley. A R & Son). (I. 2. 5. 10. II. 14)
Wilson. P M.Co.d 2. 7 II. 12. 13. 15 16.
18)
Worthinglon Pump Inc . (I. 2. 7. 11. 12 13.15.
16)
RAILROAD CAR LOADING
(SEE LOADING EQUIPMENT, R.R.
CAR: UNIT-TRAIN LOADING)
RAILROADS, RAILWAYS
Atlantic Track 4 Turnout Co
Atlas Railroad Construction Co
Baltimore & Ohio R R Co
Bessemer & Lake Erie RR
Consolidated Railway Corp.
Uravo Corp
Louisville 4 Nashville RR
Midwest Steel Oiv. Midwest Corp
RAILROAD CARS
ACF Industries. Inc
Bethlehem Steel Corp
Firslrnark Morrison Inc.
Greenville Steel Car Co
McDowell Wellman fngrg Co
Ortner Freight Car Co
Pullmjn Standard OH . Pullman Inc
Whiltdker Corp
REAGENTS
American Cydnamid Co. Industrial Chemicals A
Plastics Ov
American Mmethem Corp
Ashland Chemical Co
Beckman instruments, Inc
Gallon Corp
du Pont de Nemours. E! I & Co Inc
Fisher Scientific Co
Hercules Inc
Preiier/Mineco DIV.. Preuer Scientific Inc
Rivervde Polymer Corp
Union Carbide Corp
710
-------
RECLAMATION
TREES OR PLANTS
SEEDING
SEEDING EQUIPMENT
4. EROSION CONTROL
Conwed Corp, Environmental Products Div. (2)
Finn Equipment Co . (3)
Gull Slates Paper Corp. (4)
Hanson, R A.. Disc.. Lid.
Hardy Plants
Remco Industries. (2. 3)
U S Gypsum Co.. (2)
RECORDERS
I. LABORATORY
2 OPERATING HOUR
3. TEMPERATURE
Atco.Bnslolftv.il. 3)
American Meter Div. Singer Co. The. (3)
Babcock I Wilcoi. (3)
Bacharach Instrument Co. Mining Oiv. (I. 2. 3)
Bauscn 4 lomb. SOPOOiv.. (1)
BecVman Instruments. Inc .(1.3)
Capital Controls Co. (I)
Fisher Scientific Co. (I. 3)
Fo>boroCo. The. (I. 2. 3)
General Electric Co. DC Motor & Generator
Oepi.(2)
General Electric Co. Industrial Sales Div. (1. 2.
3)
GenRad.(I)
Honeywell Inc . Process Control Oiv. (1, 2. 3)
Leeds & NorthrupCo.il. 3)
Measurement I Control Systems Div.. Gulton In-
dustries Inc. (1. 3)
Mineral Services Inc . (2)
National Environmental Inst Inc
Preis«r/Mineco Div. Preiser Scientific Inc. (1. 2.
3)
Sangamo Electric Co. (I)
Sprengnether. W F. instrument Co Inc. (1)
TOTCO Div -Baker Oil Tools. Inc . (2)
Westinghouse Electric Corp. (3)
•RIVER-LOADING PLANTS
American Commercial Barge Line Co
Badger Construction Co.. Div ol Mellon-Stuart
Co.
Dravo Corp
Fairiietd Engineering Co
Heyl t Patterson. Inc
Jenkins ol Rettord Ltd
McDowell-Wellman Engrg Co
Mintec/lnternattonal. Div of Barber Greene
Treadwell Corp
Webb. Jervis B. Co.
REGULATORS
1. PRESSURE
2. TEMPERATURE
3. VOLTAGE
4. WATER-LEVEL
Adams Equipment Co.. Inc. (I. 2)
Aiiis Chalmers. (3)
American Meter Oiv.. Singer Co. The, (1)
American Rectifier Corp. (3)
•miter Mine 4 Smelter Supply. (I)
Aro Corp. The, (1)
Beckman Instruments. Inc.. (1. 3)
CSf Mm? Service Co. (1)
Cashco. Inc. (I. 2. 4)
Compton Electrical Equipment Corp. (3)
DuflNortonCo.O)
FMC Corp Agricultural Machinery Div
Fisher Controls Co. (1)
FlygtCorp.(4)
FoiboroCo, The. (I. 2)
General Fleclric Co Industrial Sales Div. 11. ?,
3)
Grnrral [quipment A Mfg Co . Inc . (3)
GmRad. (3)
Hayden Nilos Contlo* I Id . (I)
Honeywell In;. Proms Control Div . (I, I. 4)
Kay Rly Inc.. (4)
hncoln SI Louis Oiv ol McNeil Corp . (11
Louis AIM Div . Litton Industrial Products. Inc , (3)
McGraw-Edison Co . Power Systems Oiv.. (3)
Measurement & Control Systems Div.. Gullon In
dustneslnc.. (I. 2)
Modern Engineering Co.. (1)
Ohio Transformer Corp. (3)
Preiser /Mmeco Div.. Preiser Scientific Inc , ( 1 . 2,
3.4)
Preslolile Electrical Div. ol Eltta Corp. (3)
Rapid Electric Co . Inc . (3)
Scon Aviation. A Div ol A T-0. Inc.. (1)
Spraying Systems Co.. ( 1 )
Thor Power Tool Co.. (I)
Union Carbide Corp. (1)
Unique Products Co.. (2. 4) ^
Westinghouse Electric Corp.. (1)
W*gand. Edwin L.. Div.. Emerson Elec. Co . (2)
SAFETY EQUIPMENT AND
ACCESSORIES
1 SAFETY BELTS
2 SAFETY DISPLAYS. SIGNS
3 SAFETY FOOTGEAR. LEATHER
4 SAFETY FOOTGEAR. RUBBER
5. SAFETY HEADGEAR
6 SAFETY HOOKS
7. SAFETY SIGNS. REFLECTORl^ED
8 SAFETY SPECTACLES
9 SELF-RESCUERS
AO Salety Products. Div ol Amer Ootndl Corp .
(5.8)
Aldon Company. The. (7)
American Optical Corp, (2. 5. 6)
ATOInc.
Bacharacn Instrument Co . Mining Div
Bauscn & lomb. SOPO Oiv . (5. 1)
Big Sandy Electric & Supply Co . Inc
Bowman Distribution. Barnes Group. Inc . (2. 5.
6. 7. 8)
Bollard, E 0 Co.. (S. 6)
CSE Mine Service Co. (5. 8) •
Crosby Group. (6)
Oi, 8. 9)
National Mine Service Co . (5. 7. 8. 9)
Norton Co., (5)
Onoi. me
Prciser/Mmeco Oiv . Preiser Scientific Inc . (2. 3.
4.7)
Pulmosan Safety Equip Co. (5. 6. 8)
Red Wing Shoe Co., .Inc. .(3)
Rock Teds. Inc
Rose Manufacturing Co.. ( I )
Sala international. (6)
Servus Rubber Co , (4)
Seton Name Plate Corp . (2. 7)
Shannon Optical Co . Inc . (5. 7. 8)
Speakman Co
TreileborgRubberCo.lnc.(4)
Tube-Lok Products Div of Portland Wire & Iron
Uniroyal. Inc . (4)
Um-Tooi Attachments. Inc
Warn industries
Welsh Oiv ol Teitron. (5. 8)
Willson Products Oiv . ESB. Inc
SAMPLERS
1 COAL
2 COAL, AIITOMAIIC
rfunrnnn ial Tpstmg A I ntfmo*rin(( ' " ri ;•
F jirlwM I Humming Cn. (I. ')
(,ilionS.i«nl.i, (I. 7)
Hnlrtif. llro't In' . II. 7)
lluliiilrial Crwitrm linn ill lainrtuiil Itn
loy Mlk To. DtTllvFi I l|iii|mirnl |j,v
lively Mlu & f i|iii|lillfint l.i)
Mi.Nally PilMiurs Ml* toru (I..1!
PriMi /Mnwu Div , I'n-iser Sc lentiln Ira ( 1 .
Ramsey Engineering, Co. (1. 2)
Redding Co. James A. (1. 2)
Sala International
Sala Machine Works Ltd. (1. 2)
SturtevantMiilCo.il. 2)
Wilson. R M. Co.. (1.2)
Workman Developments. Inc. (1. 2)
SCALE-WEIGHT RECORDERS
Cardinal Scale Mlg Co
Concrete Equipment Co, Inc.
Fairbanks Weighing Div.. Colt industries
Gardner-Denver Co
Howe Richardson Scale Co
K-Tron Corp,
Railweight. Inc.
Ramsey Engineering. Co
Revere Corp. ol America. Sub ol Neptune mil
Corp.
Slreeter Amel. Div. of Mangood Corp
Thayer Scale Hyer Industries
Thurman Scale Co Div. Thurman Mlg Co
West Virginia Bell Sales & Repairs Inc
SCALES
(SEE ALSO CONVEYOR WEIGHERS.
LABORATORY TESTING EQUIPMENT)
1. MINE-CAR WEIGHING
2 R R. CAR WEIGHING
3. TRUCK WEIGHING
ASEAInc.(l.2)
Auto Weigh Inc
Baltimore & Ohio R S Co. (21
Cardinal Scale Mlg. Co
Concrete Equipment Co.. Inc
Duple. Mill S. Mlu Co (3)
Fairbanks Weighing Div. Coll lnduslr.es (1.2 3)
Gardner-Denver Co. (I 2. 3)
Howe Richardson Scale Co. (1. 2. 3)
Inflo Resomelrt Sole Inc.
Kay-Ray Inc
Kilo-Wate Inc. (2. 3)
Lively Mlg. & Equipment Co. (2. 3)
Logan Corp. (3)
Mineral Services Inc. (2)
Railweight. Inc. (1,2. 3)
Ramsey Engineering, to '
Revere Corp ol America. SuP ol Neptune Intl
Corp. 11 2. 3)
Slreeter Arnet. Div ol Mangood Corp. 11 2. 3|
Te*as Nuclear
Thurman Scale Co Div Thurman Mlg Co (1 2
3)
West Virginia 6VH Sales & Repairs Inc II. 2. 3)
Wilson R M Co il. 2. 3)
WmslowScaleCo.(3l
SCRAPER TIPS, TEETH
Amsco Div Abei Corp
Caterpillar Tractor Co
ESCO Corp
Hensley Industries me
SCRAPERS
I. SELF POWERED, EARTH MOVING
2 SHOT HOLE
3 TRACTOR-DRAWN.
EARTHMOVING
4. UNDERGROUND
CaiOCorp.M)
Cdtr.DiHar Jrario' T.o (I. 3l
ClrfDi fquipmenl To f nnslfin !mi' Ws< hmn
0., (I)
r>»*'F A ft> in
hilt Allit t.niKl'ii'lXi" Mrtrr'Pfil'f >ri' f I |
'<)'f1 1'Kttrir Ji l'c(.n P A fw. | I
|,,lprf.flh,tf,*l Mlr^tl t n ft I
f'-f Ml( (.'i (Ki'Mpr .(.('(»",en I I.., M)
M.».'i| '...ll'""- "" 4»
n.-.tt ri|iii|}>ii«i>i (,» i i i if
'. & ', M*(fi.(ir», '^1 Irii. (4)
I.FM IXv '".Wt. (I)
WABCO Coniliuclxin ^nd Mininjj ltjuip*n»j
Group *n American Standard Co (1.3)
Waiai industries ltd, (4)
711
-------
SCREEN CLOTH HEATERS
Cl Tyler Inc
Hanco International Div ol Hannon f lectric Co.
Midwestern Industries. Inc.. Screen Meeting
Transformers Div.
Sm:co Corp.
Universal Vibrating Screen Co.
SCREEN
1 MESH CLOTH
2. PERFORATED. CENTRIFUGAL
DRYERS
3 ROD-TYPE
4 RUBBER
5. SPACE ClOTH .
6. WEDGE BAR & WIRE
7. TOLYURATHANE
Belleville Wire Cloth Co. Inc. (I)
Bi.DyVimmer Engrg Co. (3. 6)
Bonded Scale & Machine Co, (1. 5. 6)
Buffalo Wire Works Co. Inc. (I. 5)
CE Tyler Inc.. (1, 3.4.5.6.7)
Card Corp. (2)
Centrifugal 4 Mechanical Industries. Inc. (2. 6)
Cincinnati RuDDer Mlg Co.. Oiv. ol Stewart-
Warner Corp. (4)
Cie.eland Wire Cloth & Mlg Co. (I. 5)
Durei Products. Inc. Nail Wire Cloth Div. (I. 2.
3 4. S. 6)
Fairmont Supply Co.. (I. 2. 6)
Greening Donald Co Ltd. (1. 2. 5)
Guy an Mach.nery Co (1)
Harrington & King Perforating. (2)
HendricK Mlg Co.. (2. 3. 4. 6)
Hewitt-Robins Div.. Uton Systems. Inc , (1, 3)
Hoy! Wire Cloth Co , (5)
Industrial Contracting ol Fairmont. Inc.. (I)
Iowa Manufacturing Co. (I)
Jeffrey Mfg Div.. Dresser Industries Inc.
Johnson Div. Universal Oil Products. (6)
Laubemlem Mfg Co. (2. 4)
Lmate* Corp. of America, (4)
Logan Corp.. (1. 2)
I udio*-Saylor Wire Cloth. Div. G.S.I.. (1. 5)
McBride Industries Inc.
McKty Perforating Co., Inc.. (2)
Midwestern Industries. Inc.. Screen Heating
Transformers Div. (I. 5)
National Filler Media Corp. (1)
National-Standard Co. Perl Melon Div. (2. 6)
Redding Co. James A. 0. ? 3, 4. 5. 6)
Simplxitir Engineering, II)
Smico Corp
SWECO. Inc.(l)
Trelleborg RuDDer Co. Inc. (4)
Umlioc limited
Waiai Industries Ltd. (4)
Wedge Wire Corp. (2 6)
West Virginia Ben Sales & Repairs Inc, (1.4)
•Wilson. R M.Co.<2. 3. 6)
Wire Cctfr Enterprises. Inc. (I. 5)
SCREEN PLATE
1. PERFORATED
2. PERFORATED. RUBBER-CLAD
American Altoy Steel, Inc, (1)
Bonded Scale i Machine Co.. (I)
Card Corp. (1)
Cleveland Wire doth t Mfg. Co.
Durei Products. Inc.. Nat] Wire Cloth Div.. (1.2)
Fairmont Supply Co. (1.2)
Greening Donald Co Ltd.. (1. 2)
Guyan Machinery Co.. (1)
Harrington S King Perforating. (1)
HendncKMfg. Co.. (1.2)
Hoyt Wire Cloth Co.. (1.2)
International Alloy Steel Div.. Curtis Noll Corp.
(I)
Iowa Manufacturing Co, (1)
Jeffrey Mlg On.. Dresser Industries Inc. (1. 2)
KanaohiMfg Co.(l)
LaubenjteinMis; Co, (1,2)
Linatei Corp. r/America. (2)
Logan Corp, (1)
Manganese Sled Forge, Taytor-Wharton Co Div
of Hanco Corp. (1)
Manufacturers Equipment Co, The
McMey Perforating Co, Inc. (1)
McNaHy Pittsburg Mfg. Corp., (I)
Mexner Mfg. Co Inc, (1)
Naional-Stancurd Co. Perl. Metals Oiv, (I)
Portec Inc.. Pioneer Div, (I)
Redding Co James A, (1.2)
Smico Corp, (1.2)
West Virginia Bell Sales t Repairs Inc, (1. 2)
Wilson. ftM, Co, (1,2)
SCREENS
1. INCLINED STATIONARY
2. TESTING
Aggregates Equipment Inc. (1)
B»by-Zimmer Engrg Co., (1)
Bonded Scale & Machine Co, (I)
CE Tyler he, (1.2)
Cleveland Wire Clotti t Mfg. Co. (1)
El-Jay, Inc, (1)
Environment* Equip Div. FMC Corp. (I)
Fairmont Supply Co, (1)
Gilson Screen Co, (2)
Harrington i King Perforating. (1.2)
HendnctMlg. Co, (1.2)
Hewitt Rot.ni Div., Litton Systems, Inc., (1, 2)
Heyl 4 Piwrson, me.. (1)
Johnson Drv, Univerul Oil Products, (1,2)
laubenitaiMlg. Co, (1,2)
LudkM-Slytor Wire Ctotti. On. G.S.I.. (1. 2)
Portec. Inc, Pioneer Oiv., (1)
Preisw/Mmeco Oh., Preiier Scientific Inc, (2)
Reinord Inc.. Proem Machinery Oiv, (1)
Screw Equipment Co, Div. Hobam IK, (I)
Smico Corp, (1.2)
Soiiiest Inc.. (2)
SWECO. Inc. (1)
Telsmth Drv, Barber-Greene Co.. (1)
Universal Vibntmg Screen Co, (2)
Wedge Wire Corp. (I)
WEMCO Drv, Enviroteth Corp., (1)
Wilson, R. M, Co., (1)
SCREENING MACHINES
1 REVOLVING
2 SHAKING
3. VIBRATING
Aggregates Equipment Inc.. (2. 3)
Allis-Chalmers. (3)
Allis-Chakrm. Crushing & Screening Equip-
ment, (3)
Barber-Greene Co, (3)
Bonded Scale & Machine Co., (3)
CE Tyler Inc., (1. 2, 3)
Card Corp, (1)
Connellsville Corp, (2)
Deistef Concentrator Co Inc, The. (3)
fleeter Machine Co. IK , (3)
Derrick Mfg. Co,,' (3)
Draw Corp, (2. 3)
El-Jay, Inc. (3)
Erie; Magnetics, (3)
FMC Corp, Material Handling Equipmeni ftv., (3)
Fredrik Mogensen AB, (3)
Fuller Co, A GaU Co. (3)
General Kinematics Corp, (3)
Gruendler Crusher & Pulverizer Co, (1. 3)
Guyan Machinery Co, (3)
Hammermills. IK, SuD. of PettiDone Corp. (3)
Iowa Manufacturing Co, (3)
Jeffrey Mfg. Div, Dresser Industries IK, (2. 3)
KHD Industrieanlagen AG. HumDoldt Wedag, (1.
2.3)
Kanawha Mfg Co, (2)
KreDs Engineers, (2, 3)
Laubenstein Mlg. Co, (1. 2. 3)
Livery Mlg. * Equipmeni Co, (2, 3)
Logan Corp, (3)
Machinoeupwt, (1.3)
McLanahan Corp, (1)
McNaily Pinsburg Mfg Corp., (2)
Midwestern Industries, Inc.. Screen Heating
Transformers Drv, (1. 2. 3)
Mineral Services IK, (2. 3)
Mmtec/lnternalional. Div. of Barber Greene. (3)
National Engineering Co (3)
Portec. Inc. Pioneer Div.. (2. 3)
Preiser/Mineco Div, Preiser Scientific Inc . (1, 2,
3)
Reinord Inc, (3)
Rennord Inc, Process Machinery Div, (1. 2. 3)
Rish Equipment Co. Material Handling Systems
Div.
Rock Industries Machinery Corp .(1.2.3)
Screen Equipment Co, Div. Hobam Inc . (3)
Simplicity Engineering. (3)
Smico Corp. (3)
Sorout-Waloron. Koppers Co, Inc, (2 3)
Slurtevant Mill Co, (3)
SWECO. Inc. (2. 3)
Telsmitfi Div. Barber-Greene Co, (3)
Umlloc Limited
Universal Road Machinery Co, (I)
Univerul Vibrating Screen Co (3)
West Virg,nia Bell Sales * Repairs Inc. (3)
Wilson. R. M, Co, (2. 3)
SCREENING PLANTS,
PORTABLE
Aggregites equipment Inc.
Allis-Cnalmert. Crushing i Screening Equipment
Bartxr Greene Co
Bonded Scale & Machine Co
CE Tyler Inc
El Jay. Inc
Giuendler Crusher & Puhreruer Co.
Guyan Machinery Co
Hamnwrmilli. IK . Sub of Pettibone Corp
Hevnn-Robms Div, Lifton Systems. Inc
lota ManulKtunng Co
Jeffrey Mfg On, Drtswr Industries Inc
KHD Industrcanlagen AG, HurnboUi Wedag
Mintec/lntemaiionai. Div of Barber-Greene
Ore Reclamation Co
Portec, Inc . Pioneer Div.
Reinord Inc. Process Machinery Oiv
Risft Equipmeni Co, Material Handling Systems
Div
Rock Industrie Machinery Corp
Screen Equipment Co, On. Hobam IK
Telsmrih Div. Barber Greene Co
Wilson, R. M.Co
SCRUBBERS
I. AIR, GAS
2. DRYER-EXHAUST
ft.dial! Mills Ltd, II)
Aggregates Equipment Inc.
Air Pollution Control Operations, FMC Corp. (I)
American Air Filler Co, Inc, (1, 2)
flabcock 4 Wilcoi. (1)
Bethlehem Steel Corp.
CSE Mine Service Co, (1.2)
Draw Corp. (1)
DuconCo, IK, The. (1.2)
Enloleter Inc.. (2)
Envirooming IK, (I. 2)
Environmental Equip Drv, FMC Corp, (1)
Fuller Co. A GaU Co. (1)
General Resource Corp. (I)
Gundlach. T. J, Machine Co, Div. J M J Indus-
tries. Inc.
Hammermills. IK . Sub ol Pettibone Corp
Heil Process Equipment Co, r>v ol Dan indus-
tries. IK. (I. 2)
Hunslel Holdings Ltd, Hunslet Engine Works. (I)
Industrial Contracting of Fairmont. IK, (1.2)
Johnson-March Corp, The. (1)
JovMfg Co.(l)
Joy Mfg Co (UK) Ltd. (I)
KHD Induslrieanlagtn AG. HumDoWl Wedag. (1.
2)
Koch Engineering Co, IK. (1. 2)
Krebs Engineers. (1, 2)
McLananan Corp
National Mine Service Co.
Research Cornell. Inc. (I)
Sly. W.W, Mil Co, (1.2)
Telsmilh Oiv. Barber-Greene Co
UnitedMcGillCorp. (1.2)
Universal Road Machinery Co
West Virginia Belt Sales i Repairs Inc. (1)
Western Precipitation On. Joy Mlg Co. (I)
Willis » Paul Corp.. The. (I)
SEPARATORS, HEAVY
MEDIUM
(SEE WASHERS. HEAVY MEDIUM)
SIEVES, TESTING
CE Tyler Inc
Ouren Products. Inc Natl. Wire Cloth Div
Gilson Screen Co.
Hacker Instruments Inc.
Hendrck Mlg Co.
Joy Mlg. Co, Denver Equipmeni Drv
KHO Induslrieanlagen AG. Humboldt Wedag
712
-------
Lautenstem Mfg. Co.
Midwestern Industries, Inc.. Screen Heating
Transformers Dw.
Preiser/Mineco Div, Preiser Scientific Inc.
Smico Corp.
Sallesl. Inc.
SIEVE SHAKERS
CE Tyler Inc.
Duiei Products. Inc.. Natl. Wire Cloth DM.
FMC Corp.. Material Handling Equipment Div.
Gilson Screen Co.
Hacker Instruments Inc.
Joy Mlg Co., Denver Equipment Oiv.
Laubenslein Mlg. Co.
Midwestern Industries, Inc. Screen Heating
Transformers Div.
Mineral Services Inc.
Preiser/Mineco Div. Preiser Scientilic Inc.
Smico Corp
Soiltesi. inc.
SILOS, ASH, COAL,
ROCK-DUST & SAND
STORAGE
Aggregates Equipment Inc.
Armco Sieel Corp. Product Info
Badger Construction Co. On. ot Mellon Stuart
Co
Concrete Equipment Co.. Inc
Ferro-Tech. Inc.
First Colony Corp
Fruehauf Div . Fruehauf Corp
Holmes Bros. Inc.
Industrial Pneumatic Systems. Sub. of Industrial
Contracting of Fairmont. Inc.
MacDonald Engineering Co
Manena Concrete Co.
Nell & Fry, Inc
Rutlmann Companies
SLUDGE RECOVERY
SYSTEMS
Ametet
Bird Machine Co.. Inc
Envirei. Inc.
Environmental Equip. Div. FMC Corp.
Envirotech Corp. Eimco 8SP Div.
Fairwd Engineering Co
Feeco International. Inc.
Hell Process Equipment Co, Div. of Dart Indus
tries. Inc.
Heyl & Patterson. Inc.
Holley. Kenney, Schott. Inc
Jeflrey Mfg. Div.. Dresser Industries Inc.
Jov Mil. Co.. Denver Equipment Div.
Kaiser Engineers. Inc.
Kay-Ray Inc.
Reinord Inc
Sala International
Sauerman Bros. Inc.
Unilloc Limited
SPRAY COMPOUNDS, COAL
& DUST
Amoco Ol Company
DOMII On. of the DM Chemical Co.
Euon Co.. U.SA
Johnson-March Corp.. The
PreiB/Mineco On., Preiser Scientilic Inc.
Shell Oil Co
Witson. B M, Co
SPRAY OILS
Amoco Ol Company
Ashland CM « Refining Co.
Bowman Distribution. Barnes Group. Inc.
Eiion Co.. U.S.A
Gulf Of Corp.. Dept DM
KeenanOilCo.
Shed Oil Co.
Sun CM Co.
Tejucolnc.
Viking Oil « Machinery Co.
SPRAYING EQUIPMENT
(SEE ALSO OUSTPROOFING
EQUIPMENT)
1. OIL
2. WATtR & COMPOUNDS
Ashland Oil & Refining Co.. (1)
Austin, J. P. Inc.. (2)
BAy Wyandotte Corp, (2)
Bete Fog Noute. Inc., (2)
Clayton Mfg. Co. (2)
Delavan Mlg Co
Dover Conveyor & Equipment Co, Inc.. (2)
FMC Corp., Agricultural Machinery Div.. (2)
Gammeter, W F.. Co.
Hayden-Nitos Conltow Ltd.
Industrial Pneumatic Systems. Sub. of Industrial
Contracting of Fairmont, Inc.
Jarxo, Inc.. (2)
Johnson-March Corp.. The. (2)
Johnston-Morehouse-Dicliey Co.. (2)
Lee. A.L.. 4 Co.. Inc.. (2)
Lee Supply Co., Inc.
Lincoln St. Louis Div. ot McNeil Corp.
Michael Walters Ind.
Preiser/Mineco Div., Preiser Scientific Inc.. (2)
Spraying Systems Co.. (1.2)
Viking Oil 4 Machinery Co.
Wilson. R. M . Co.. (2)
STACKS
Bethlehem Steel Corp.
Canton Stoker Corp.
Heil Process Equipment Co.. Div. of Dart Indus-
tries. Inc.
Kanawha Mfg. Co.
Treadwell Corp.
STACKERS, RECLAIMERS,
COAL
Aggregates Equipment Inc.
Barber-Greene Co.
Concrete Equipment Co. Inc.
Continental Conveyor & Equipment Co.
OEMAG Lauchhammer
Dover Conveyor & Equipment Co.. Inc.
Dravo Corp.
FMC Corp., Link-Belt Material Handling Systems
Oiv.
Fairiield Engineering Co.
GEC Mechanical Handling Ltd.
Hanson. R A, Disc.. Ltd.
Hewitt-Robins Div.. Litton Systems. Inc.
Heyl & Patterson. Inc.
Industrial Contracting of Fairmont. Inc.
Iowa Manufacturing Co
Jeffrey Mlg Div.. Dresser Industries Inc.
Jenkins of Rerford Ltd.
Lake Shore. Inc.
Marsh, E. F.. Engineering Co.
McDowell Wellman Engrg Co
McNally Pittsburg Mlg Corp.
Mintec/lnternational. Div oi Barber-Greene
0 4 K Orenstein & Koppel AG
Peerless Conveyor & Mfg. Co.. Inc.
Reinord Inc.. Process Machinery Div.
Stephens-Adamson
Webb. Jems B. Co
Willis & Paul Corp., The
Wilson. R. M.. Co.
STORAGE PILE PROTECTIVE
COATINGS
Adhesive Engineering Co.
Dowell Div ol the Dow Chemical Co
Johnson-March Corp. The
Preiser/Mmeto Div. Preiser Suenlilir me
Wilson. R M . Co
STORAGE & RECLAIMING
SYSTEMS
Aico. Integrated Handling System-. Div
Alpine Equipment Corp
HarbenGtoene Co
DldVO Corp
FMC Corp. link Hell Material llaiullinij Systems
Div
lairtield Engineering Co
feeco International. Inc
(iEC Mechanical Handling Ltd
Hanson, R A . Disc. Ltd •
Hewitt HoDim Div . Litton Systems Inc
Heyl & Patterson. Inc
Holley, Kenney. Schott. Inc
Industrial Contracting ol Fanmonl. Inc
Iowa Manufacturing Co
Jellrey Mlg Div.. Dresser Industries Inc
Kaiser Engineers. Inc
Kanawha Mlg Co
lively Mlg & Equipment Co
lung-AirdoiCo ADiv.otineMdiinonGrouc he
Marsh. E F. Engineering Co
McDowell Wellman Engrg Co
McNally Pittsburg Mlg Corp
Mmtec/lnternational. Div ol Baiber Greene
Nell & Fry. Inc
ORBA Corp
Paceco. A Div of Fruehaul Corp
Roberts & Schaefer Co.
Sauerman Bros. Inc.
Slearns Roger Inc
Slephens-Adamson
Treadwell Corp.
Vibranetics. Inc.
Webb, Jervis 6, Co.
Westmghouse Electric Corp
Willis 1 Paul Corp. The
Wilson. R M. Co
TABLE DECKS, WASHING
Deister Concentrator Co. IK., The
I mate* Corp. ol Amenta
Poly-Hi. Inc.
West Virginia Belt Sales & Repairs Inc.
TABLES
(SEE WASHERS, COAL. TABLE-TYPE)
TANKS
1 CLARIFYING. SLUDGE-RECOVERY
2. CONCRETE
3. RUBBER LINED
• 4 STEEL
5. WOOD
6 PLAS1IC
ACF Industries. Inc., (4)
ASV Engineering Ltd. (I. 3.4)
American Alloy Steel. Inc. (4)
Armco Steel Corp.. Product into (4|
Bethlehem Steel Corp. (1.3. 4)
Cincinnati Rubber Mlg. Co O» ol Stewart-
Warner Corp. (3)
Concrete Equipment Co. Inc . (4)
Environeering. Inc, (1)
Environmental Equip Div. FMC Corp . (! 4)
Equipment Mlg Services. Inc . (4)
Fabricated Metals Industries. Inc
First Colony Corp. (2)
Gahgher Co. The. (3)
Gates Rubber Co . The. (3)
Goodyear T.re & Rubber Co. (3)
Heil Process Equipment Co. Div ol Dart Indus
tries, inc. 13. 4)
HerOnckMfg Co.. (I)
Holmes Bros Inc. (4)
HuwoodlrwmCo.(4)
Industrial Contracting ol Fairmont. Inc 0 4)
industrial Pneumatic Systems. Sub ol Industrial
Contracting ol Fairmont. Inc . (4)
Joy Mfg Co. Denver Equipment Div. (1. 3. 4)
Kanawha Mfg Co. (4)
lee Supply Co. Inc. (4. 6)
Lmatei Corp ol America (3)
lively Mlg 1 Equipment Co ,(I 2 4)
Manena Concrete Co. (2)
McNally Pittsburg Mlg Corp. II 4)
Nell & Fry. Inc (2)
Preiser/Mineco Div. Preiser Scientilic Inc . 14, 6)
Rubber Engineering & Mfg, Co. (3)
Ruttmann Companies. (2)
Somerset Welding 4 Sletl Inc. (4)
Steams-Roger Inc , (3. 4)
Telsmith Oiv. Barber-Greene Co, (I. 4)
Unitloc Limited
United States Steel Corp, (4)
West Virginia Belt Sales * Repairs Inc. (1 3 6)
Willis 4 (Saul Corp. The. (4)
Workman Developments. Inc, (6)
713
-------
TEMPERATURE
INDICATORS,
CONTROLLERS
Acco. Bristol Div.
Allen Bradley Co
Alnor Instrument Co.
American Meter On.. Singer Co.. The
Bacharach inslrument Co.. Mining Div.
Barnes Engineering Co.
Beckman Instruments. Inc
Communication & Control Eng Co. Ltd.
Dans Instrument Mlg. Co
Foiboro Co . The
General Electric Co.. Industrial Sales Div
General Electric Co, Instrument Products Opera-
tien
Honeywell Inc . Process Control Div
Huwood-lrwin Co.
Leeds 4 Northrup Co.
3MCo.
Measurement 4 Control Systems Div , Gulton In-
dustnes Inc.
Pace Transducer Co.. Div. of C J. Enterprises
Preiser/Mineco On.. Preiser Scientific Inc.
Pyott-Boone. Inc.
Taylor Inslrument Process Control Div Sybron
Corp.
Westinfhouse Electric Corp
THICKENERS
Amenon Minechem Corp.
CUfviCorp
DoT-OlrwInc.
Envim. Inc.
EmvoOuf. I Div. of Amsttr Corp.
EmironrwnUI Equip. On., FMC Corp.
ErrnrotKft Corp.. Cimco BSP On.
Goodrich. B. f .. Chemictl Co.
Hendridi Mil. Co.
Hercutejlnc.
Heyt & Patterson. Inc.
Joy Mt|. Co., Denver Equipment Div.
KHD Hdustrietntaien AG. Humbotdt Wedag
McNaly Pittsliurj Mtg. Corp.
Mnenl Services he,
Parkibn Corp,
Sala International
Salt MKhm Works LtrJ.
Unlimited
Wot Vrpria Belt Safes I Repairs Inc
THICKENING. STABILIZING.
SUSPENDING AGENTS
Ametxjn Ctinamid Co.. Industrial Chemicals 4
Plashes On.
BASF Wyindotte Corp.
BeD Laboratories
CalgonCorp
Dowel Div. of the Dow Cherractl Co.
GAT Corp
Goodrich. B. F.. Chemictf Co.
Hendnck Mto Co.
Nako Chemical Co.
Prehcr/Vineco On.. Preuer Scientific Inc.
Unite United
TRUCKS &
TRACTOR TRAILERS
1. ON-HIGHWAY
2. OFF-HIGHWAY
Attwy Products Corp., (2)
Caterpillar Tractor Co, (2)
Challenge-Cook Bros.. Inc.. (1.2)
Cusnman-OMC Lincoln. (2)
D»n Truck Company, (2)
Eimco Minini Machinery. EnvirotKh Cor;. (?)
Eudid. Inc, Sub of White Motor Corp, (2)
Fairbanks Co. The. (2)
Ford On. of Ford Motor Co.. (1, 2)
Fruenaul Ore, Frueheut Corp.. (I. 2)
CMC Truck 4 CoKti On.
Gobdbary Engineering Co. (2)
Inttmational Hantsttr Co. (I. 2)
km Mow Tooting Co.. Inc.. (2)
ISCOMfg Co.. (2)
Kemnrth Truck Co. (1.2)
Ko*ums Industri AB. (1,2)
Kress Corp.. (2)
MackTrucks. Inc. (1.2)
Oshkoth Truck Corp. (1.2)
Rish Equipment Co. Intl.
Sterling Custom Budt Trucks
Tere«On..GMC.(2)
WABCO Construction and Mining Equipment
Group, in American-Standard Co. (2)
Wagner Mining Equip, (2)
White Motor Corp True* Group. (1. 2)
UNIT TRAIN STORAGE &
LOADING FACILITIES
Baltimore & Ohio R.R. Co.
Barber-Greene Co.
Daniels Company. The
DEMAG Lauchhammer
DravoCorp
FMC Corp.. Link-Belt Material Handling Systems
Div.
Fairtietd Engineering Co.
Feeco International. Inc.
GEC Mechanical Handling Ltd
Hanson, R.A.. Disc.. Ltd.
Heyl & Patterson. Inc.
Holley. Kenney. Schorl. Inc
Industrial Contracting of Fairmont. Inc
Irvin-McKeNy Co.. The
Kaiser Engineers. IK.
Kanawha Mfg Co
Lively Mtg. 4 Equipment Co
McDowell-Wellman Cngrg Co
McNally Pittsburg Mtg_ Corp.
Mintec/lnternational. Div of Barber-Greene
Pullman Torkefson Co
Rish Equipment Co.. Material Handling Systems
Div.
Ruttmann Companies
Stephens-Adamson
Wilson. R M. Co.
VALVE ACTUATORS,
OPERATORS
Beckman Instruments, Inc.
Cashes, inc.
Clayton Mark-Pacific Valves. Div of Mark Con-
trols Corp.
Crane Co.
DeZurik, a Unit of General Signal
Dunron Co., Inc. The
Equipment Mtg Services. Inc.
Fairmont Supply Co.
Fisher Controls Co.
General Equipment & Mfg. Co, Inc.
Geneml Resource Corp.
Homestead Industries, he.
Honeywell Inc., Process Control On.
Jenkins Bros.
Meisurement 4 Control Systems On.. Gulton In-
dustnes Inc.
North American Mfg. Co.
Philadelphia Gear Corp.
RKL Controls
toco International, Inc.
Rockwell International Flow Control On.
Vetaulx Co of America
Wachs. E. H, Co.
Wesbnghouse Electric Corp.
Wilson, R M.. Co.
VALVES
1. AIR
2. BLOW-OFF
3. CHECK
4. CONTROL
5. DIAPHRAGM
6. FOOT
7. GATE
B. GLOBE
9. AIR, HYDRAULIC, MOTOR
OPERATED
10 NEEDLE
1 1 OKI! ICC
1? PINCH
13 PLUG
14 HUMP
15 Rriltl
HYDRAULIC (SFF HYOHAU11C
VALVI;S)
ACF Industries. Inc. (7. 13. I b)
AMF Inc.. (14)
A-S H Pump, Oiv ol I nvirotech Corp. (3)
* Adams Eouipment Co. Inc.. (3. 6. 10)
Alemite 4 Instrument Div Stewart-Warner Corp.
(1.4)
American Air Filter Co. Inc. (3. b)
American Meter Div. Singer Co. The. (I. 4. b.
10. Ib)
Anchor Coupling Co.. Inc.. (3)
Anchor/Darting Valve Co. (3. 7. 8. 9)
Annter Mine 4 Smelter Supply. (I. 2. 3. 4. 6. 7.
8. 10. II. 12. IS)
Armco Steel Corp. Product kilo.. (2. 7. 14)
Aro Corp. The. (1.3. 4.6. 10. IS)
Barxock 4 Wikoi. (1.5, 10. 13)
Barksdale Controls D»./DELAVAL Tun>ne Inc.
(1.4,9)
Bla« Knoi Equipment. Inc. (7)
Buwman Distribution. Barnes Group. Inc.(I 7)
Brantord Vibrator Co.. The. On ol Electro Me
chanics. Inc. (1.2.6)
BrumngCo, (3. 15)
Cashco.lnc.,(1.2. 3.4. 5.8.9.10. II. 13.14.
15)
ClarksonCo.(4. 5. 12. 14)
Clayton Mark Pacific Valves. On. ol Mark Con-
trols Corp. (1.2. 3.4.5.6.7.8.9)
Cleveland-Armstrong Corp. (7. 9)
Control Concepts, (4)
Crane Co, (1,2. 3.4. 5.6. 7. 8. 9. 10.11. 13.
14. 15)
Daniels Company. The, (12. 14)
DeZurik. a Unit ol General Sign*. (4. 7. 9. 13)
Otion Valve 4 Coupling Co. (I. 3. 4. 10)
Dresser Manufacturing. Div Dresser Industries.
Inc. (3. 7. 9)
Dunron Co . Inc.. Ihe, (4. 13)
Dyne> Div. Applied Power Inc. (3. 4. 15)
Eaton Corp. Work) Headquarters. (4)
ENERPAC. On ol Applied Power Inc.. (3. 4. 14.
15)
Equipment Mlg Services, he.. (4. 9)
FMC Corp. Agricultural Machinery &v.( 14, 15)
FMC Corp, Material Handling Equipment Div.. (5)
Fabri-Varve. (3. 7. 9)
Fairbanks Co, The. (1.2, 3. 7. 8. 10)
Fairmont Supply Co.. (3. 6. 7. B. 10. 13)
Federal Soppl, 4 Equipment Co. Inc.(14. 15)
Fisher Controls Co. (1. 4.8. 12, 15)
Flenble Valve Corp. (4. 12)
Fluid Controls Inc.. (3. 4.9 10. 15)
Fonboro Co.. The. (4. 5. 8. 9. 10)
Fuller Co. A Can Co.. (3. 7. 9. 15)
GTE Sylianialnc.d.4)
Gahgher Co, The, (5. 9. 12)
General Equipment 4 Mtg Co. Inc.. (1. 4)
General Resource Corp. (3. 4. 5. 7. 15)
Goodall Rubber Co. (14)
Coyne Pump Co. (3. 6. 7. 14)
Gullick Dobson Inll Ltd, (4)
Gustin-Bacon Div.. Aeroquip Corp. (13)
Halliburton SemcevResurch Center. (13)
HjyrJen-Nitos Conflow ltd.. (2. 3..4. 6. 10. 15)
Heyl 4 Patterson. Inc. (13)
Homestead Industries,he. (I. 4. 9. 13)
Honeywell Inc.. Process Control On. (4. 5. 8)
Huwood-lrwin Co, (4, 14. 15)
Hydraulic Products Inc.. (15)
in Grinned Corp., (3. 7. 6)
Imperial-Eastman Corp. (I. 3. 4. 5. 8. 10. 13.
15)
Industrial Rubber Products Co, (1. 3. 6. 12)
Jenkins Bros. (1.2. 3. 4. 7. 8. 9. 10. 13)
LadishCo.<3. 7.8)
Lee Supply Co . Inc, (1.2. 3.4. 5. 6. 7. 8. 9.10,
II. 12. 13)
Le Mi Valve 4 Coupling. Hose Products Div. Park-
er Hannifin Corp, (I)
linalei Corp of America. (12)
Lincoln SI Louis Dm. of McNeil Corp,(l. 2, 3.4)
Logan Corp. (3, 6. 7. 8. 13)
Lunkenheimer Co. Div ol Conval Corp. Sub ol
Condec Corp. (I. 2, 3. 7. 8, 9. 10. 15)
McNally Pimouig'Mlg Corp, (3. 7)
Mine 4 Smelter Industries. (12)
Mineral Services Inc, (4. 7. 12, 14)
Minnesota Automotive Inc, (3)
Modern Engineering Co, (10) j
Morgantown Machine 4 Hydrauvcs, Inc. Div
Nail Mine Service Co. (3. 4. 15)
North American Mlg Co. (I. 4. 9)
Ohio Hrass Co . (3. 7. 8)
Parker Mjnnilin Corp. Tube Fitting! Div. (10)
Peahodv Humus. (6)
I'helps Dwlgf Industries. Inc, (3. 7. 8)
Prriwr/MinKO ftv. Prmser SciefltlliC Inc .Ci.fi.
I. 10. Ib)
HKI Controls. (I. 4. 5, 9. 12)
HKlValreOo.lnc.O. I?)
Resurch Cornell, Inc , (1. 3. 7)
Rrxhvtoll International I loo Control On . (?. 3. 7,
0.9. IJ. 15)
Sala Machine Works I Id, (4. 12)
714
-------
• Sperry Vickers Div., Sperry Rand Corp.. (3. 4. 8.
9. 10. 13. 15)
Spraying Systems Co. (3. 4, 5)
Sprout WalSron. tappers Co.. Ine. (1)
Templeton. Kenly & Co. (3. 4. IS)
Thomas Foundries Inr n\
TRW Mission MlR Co.Oiv ol TRW Int. (3)
Union Carbide Ci.rp. (3, 4. 10. IS)
Unnoyal. Inc. (17)
United Slates Sli-el Corp. (3. 6. '. 10)
Vanan Associates. (7)
Victaulic Co ol America. (1.9. 13)
WABCO fluid Power Uv. an American Standard
Co.d 3,4,5,6. 10. 15)
Ward Hydraulics Oiv. AID Corp .(3.4)
Wealherhead Co. The. (1. 13)
West Virginia Bell Sales & Repairs Inc. (6. 12)
Western Precipitation Oiv. Joy Mlg Co . 11. 9)
Workman Developments. Inc.
WASHABILITY TESTS
Commercial Testing & Engineering Co
GEOMIN
Umlioc Limited
WASHERS, COAL
(SEE ALSO FLOTATION & TABLES.
AIR)
1 CALCIUM-CHLORIDE
2 CYCLONE. HEAVY-MEDIUM
3. CYCLONE. WATER
4 HEAVY-MEDIUM
5. HYDROSEPARATOR
6 JIG
7 LAUNDERS. TROUGH
8 FLOTATION
9 TABLE TYPE
10 UPWARD-CURRENT
ASV Engineering Ltd., (1. 2, 3. 4, 5. 6. 7. 8, 9.
10)
Barber-Greene Co, (4)
Daniels Company. The. (4. 8. 9)
Deister Concentrator Co Inc. The. (9)
Dorr Oliver Long. Lid . (2, 3. 5)
Eagle Iron Works. (3. 4. 6)
Erie; Magnetics. (4)
FMC Corp.. Agricultural Machinery Div
FMC Corp. Link-Belt Material Handling Systems
Oiv. (4. 6)
Fairmont Supply Co. (4, 5. 6. 8)
Galigher Co.. The. (8)
Garland Mlg Co. (6)
GtOMiN. (1.2. 3. 4. 5, 6. 7.8.9. 10)
Head Wnghtson 4 Co Ltd. (2. 3 4.5. 6, 7. 8)
Heyl & Patterson, inc.. (2. 3. 4. 8)
trvin-McKelvy Co. The. (4)
Jeffrey Mlg. Oiv . Dresser Industries Inc .(4.5. 6.
8)
Jenkins of RetlorrJ Ltd.. (2. 3. 4. 6. 8. 9)
Joy Mfg Co. Denver Equipment Div
KHD industneanldgen AG. Humboldt Wedag. (4.
6.8)
Kaiser Engineers. Inc.
Krebs Engineers. (2, 3}
Lmatex Corp. ol America. (3)
Lively Mtg 4 Equipment Co. (2. 3.4,6. 8.9.10)
McNally Pittsburg Mlg Corp. (2. 3. 4. 6)
Mineral Services Inc.. (2. 3)
Minerals Processing Co., Div ol Trcian Sleel Co.
(1. 4.8, 9, 10)
Mmtec'International, Div ol Barber Greene. (4)
Ore Reclamation Co . (6)
Process Equipment. Slansteel Corp. (3)
Roller Cuip.(4. 9)
SaM International, (2. 3. 8. 9)
Unilloc Limited
WfMCOD'».fnvn,HKhCorp.(?.3 4 5,8. 10)
Wilmol Enwiwrin,: Co. (2 4. 5 6. 8. 10)
WorVman Di'vi'lopmenls Inc , (7)
VIBRATION ABSORBERS,
DAMPERS
Cincinnati Rubber Mlg Co. Div ol Stpowt
Warnet Corp
Fabreck.1 Pioducls Co
Firestone lire & Rubber Co
GAF Corp
Goodall Rubber Co
Industrial Rubber Products Co
3MCo
RKl Controls
Red Valve Co. Inc
Trelleborg Rubber Co. Inc
Umroyal. Inc
Victdulic Co ol America
Wichita Clulih Co. Inc
Workman Developments. Inc
VIBRATORS
1 HIN & HOPF'IR. CMUlf
? RH HOPPE.RCAR
Aldon Company. The. (2)
Branloid Vibrator Co. The. OK ol Eleclru Me-
chanics. Inc. 11. 2)
Carman InOuSlnes. Inc, (1)
Dover Conveyor & Equipment Co. Inc. (1)
Enel Magnetics. (1)
FMC Corp. Material Handling Equipment Oiv (1
2)
GEC Mechanical Handling Ltd . (1)
Industrial Robber Products Co. (1. 2)
Jettiey Mlg Div . Uresser Industries Inc. (I)
Martin Engrg Co.d. 2)
National Air Vibrator Co.d. 2)
Preiser.'Mmeco Div. Preiser Scientific Inc.. (1.2)
Solids Flow Control Corp. (I)
Vibcolnc.(l.2)
Vibranetics. Inc. (1. 2)
Vibra-Screw Inc.. (1)
Wesl Virginia Sell Sales & Repans Inc. (I!
Wichita Clulch Co Inc (1 2)
Wilson. R M.Co.(l)
WATER CLARIFICATION &
RECLAMATION SYSTEMS
American Cyanamid Co. Industrial Chemicals &
Plastics Oiv
BIF. a urnl ol Geneial Signal
Bird Machine Co.. Inc
Calgon Corp
Carus Chemical Co.
Crane Co
Daniels Company The
Davis Inslrumenl Mlg Co
Don-Oliver Inc
Dorr Oli.pi Long Ltd
Oravo Coip
du Pont de Nemours, E I & Co Inc
Envire«. Inc
Environmental Equip Div., FMC Corp
Ennrotech Corp. Eimco B5P Div
Erie! Magnetics
Ferro-Tech Inc
Hendnck Mlg Co
Heyl & Patterson. Inc
Holley Kenney. Schott. me
Industrial Contracting of Fairmont. Inc
Industrial Pneumatic Systems, Sub ol Industrial
Contracting uf Fairmonl. Inc
Jenkins ol Reltord Lid
Joy Mlg Co. Denver Equipment Uv
Kaiser Engineers. Inc
tappers Co Inc
Lively Mlg & Equipment Co
Lotlus. Peter f. Corp
McNally Pittsburg Mlg Corp
Naico Chemical Co
NUS Corp . Robinson & Robinson Oiv
Parkson Corp
Rexnord Inc
Rohm and Haas Co
Sala international
Slearns-Roger Inc
Treadwell Corp
unilloc Limited
Westmghouse Electric Corp
WATER REPELLENTS
Amulet Mine & Smelter Supply
CJtnl. Samuel. Inc
Dow Carning Corp
(Ju Pont de Npmours. ( I & Cn Inc
3MCo
Prmtir/Miiifvo Div tViyi WnMir Inc
WATER DEMINERAtlZERS,
SOFTENERS, TREATERS
Adams tqiiipmenl Co. loc
Rrli laboratories
Calgon Corp
Capital Controls Co
Clayton Mtg Co
Crane Co
du Ponl de Nemours. E I & Co Inc
Fisher Siienlilic Co
GAf Corp
Joliiisun OK Universal Oil Products
Monsanto Co
PPll Ind.islr-es.'lnc . Chemical On
I'lpiser/Muux'O Oiv . Preiser $c*ntiln Inc
Hi'inord Im:
Rnhm and Hats Co
Shirley Machine Co. Div lasa Co'p
Westmghouse Electro Corp
Wiegand. Edwin L . Div . Emerson flee Co
WEAR PLATE, STRIPS
Ampco Metal Div. Ampco-Pittsburgh Op
Asbury Industries. Inc
Carborundum Company
International Alloy Steel On. Curtis Noll Corp
Manganese Sleel Forge. taylor-Wharton Co. Div
ol Harsco Corp.
N L Industries. Searings Div
Poly-Hi, Inc.
Slwayder Co.
Somerset Welding & Steel Inc
Stelhte Oiv, Cabot Corp
Tool Steel Gear & Pinion Co
Workman Developments. Inc
WIRE CLOTH
Belleville Wire Cloth Co. Inc
Bonded Scale & Machine Co
Buffalo Wire Works Co Inc
CE Tyler Inc
Cleveland Wire Cloth t Mtg Co
Durex Products. Ine, Nan Wire Cioth Oiv
Greening Donald Co Ltd
Hoyt Wire Cloth Co
Iowa Manufacturing Co
Keystone Steel & Wire. Div ol Keystone Con-
solidated Industries. Inc
LudlowSayhx Wire Cloth. Div GSt
Midwestern Industrie*, Inc. Screen Dealing
Translormers Div
Redding Co.. James A
Simplicity Engineering
Smico Corp.
SWECO. Inc.
Wesl Virginia Bell Sales & Repairs ln<
Wilson, R M. Co
Wire Cloth Enterprises. Inc
715
-------
Directory of Manufacturers
Bullet preceding (•) manufacturer indicates a products-information advertisement in this issue. See the adver-
tisers index on the second to last page of this issue for the page number or numbers of the advertisement(s).
• ACf Industrie}, IK.. 2300 3rd An.. P.O. 801 547, Huntington. W
VI.. 25710
A C.R. Equipment Co. Inc.. Parts On., 19615 Nottingham Ru. Cleve-
land, Oho, 44110
A & K Railroad Materials. Inc.. P.O. Boi 1276. Freeport Center.
Clearlield. Utah, 84016
• ALPS Wire Rope Corp., 2350 Lunt Ave. Elkgrove Village. Ill. 60007
AMF Inc.. 777 Westchester AM . White Plains. N. V. 10604
AMP Special Induitnej, On. ol AMP Products Corp. Valley Forge.
Pa.. 19482
AO Safety Products. On ol A/ne> Optical Corp. 14 Mecnaruc SI,
Southbndge, Mass.. 015 W
A-S-H Pump. Oi». ol Ermrotech Corp., P 0 Bo> 635. Paoli. Pa..
19301
ASV Engineering ltd.. Green Rool. York Rd. Doncaster. England.
ON58HN
• Abei Corp., Demon Div. 1160 Dublin Rd, Columbus. Ohio.43216
Abei Corp., Fncbon Product! Group, 1650 W. Big Beaver, Troy.
Mich, 48084
Abei Corp. Railnxd Pioducti Group, 530 Filth Ave.. New Yoili.
N.».. 10036
Acco Allison Campbell ON.. 875 Bridgeport Ave.. Shelton. Conn..
06484
Acco American Cham On.. 454 E. Princess St.. York. Pa.. 17403
Acco. Bristol Ov. Boi 1790. Waterbury. Conn, 06720
Acco. Cable Controls On.. 1022 E. Michigan St.. Adrian. Mich.,
49221
Acco. Craw & Monorail Systems Ov. Bon 140, Fairlield. Iowa,
52556
Acco, Eteclro-Mecti On.. 1 Research Dr.. Stratford, Conn., 06497
Acco. Hekoid Gage On., 929 Connecticut Ave.. Bridgeport, Conn.,
06602
Acco, HOISI 4 Crane Div. P. 0 Box 792. York. Pa.. 17405
Acco. Integrated Handling Systems Div, Bailes Rd . Frederick. Mel..
21701
Acco. MalletMe Casting Div, 1100 £ Princess St.. York. Pa. 17403
Acco Mining Sales Div., P 0. Boi 15537. Pittsburgh. Pa. 15244
Acco. Page Fence Div.. First & River Sis.. Monessen. Pa, 15062
Acco. Page Welding Div.. P. 0 Bo> 976. Bowling Green. Ky.. 42101
Acco. Unit Conveyor Div.. 10601 W.Belmont Ave., Franklin Park, III..
60131
• Acker Drill Co.. Inc. P. 0. Boi 830. Scranton. Pa, 18501
Acme-Hamilton Mlg. Corp.. Belting Div, E. State SI, P. 0. Boi 361.
Trenton, N. J.. 08603
Acme Machinery Co, Boi 2409. Huntington. W Va , 25725
• Acrow Corp. ol America. 396 Washington Ave, Carlstadt. N J,
07072
Adams Equipment Co., Inc.. 8421 25 Wabash. Si Louis, MO.
63134
Adhesive Engineering Co, 1411 Industrial Rd, San Carlos, Calil,
94070.
Advance Car Mover Co, Inc.. 1 12 N Outagam* SI, P 0 60.1181.
Appleton. Wis, S4911
Advanced Mining & Mlg Co, P. 0 Bo> 9387. Hunlington. W. Va,
25701
Aerial Map Service Co. 1016 Madison Ave. Pittsburgh. Pa, 15212
Aenil Surveys. Inc. 4614 Prospect Ave, Cleveland. Ohio. 44103
Aetofall Mills Ltd, 2640 So. Sheiidan Way. Mississauga. Ont.
Canada. I.5J 2M4
Awoquio Corp.. 300 S E«st Ave. Jackson. Mich. 49203
Aero Service Div, Western Geophysical Co ol Amer P1). Bin 19^9.
Houston. IX. 77001
Aggregates tqwpment liv, 9 Horseshoe Rd . Irola. Pa , I 7540
An Correction Div. UOP. Boi 1107 Dune". Conn Oh820
An LKt. Inc . P 0 Bot .142. Prorturv*. Oil. 4S6I.9
Air Pollution Control Opeiations, FMC Corp ,799 Roosevelt Rd, Glen
Ellvn. Ill, 60137
Aitfcen Products. Inc. P.O. floi 151. Geneva. Ohio. 44041
Alabama State Docks. P 0 Boi 1588. Mobile. Ala. 36601
Albright Mlg. Co Inc. 7232 N Western Ave. Chicago. Ill, 6064S
Alcoa. 1501 Alcoa Bldg. Pittsburgh Pa. 15219
Alcoa Conductor Products Co. Div. Aluminum Co ol America. 510
One Allegheny Sq. Pittsburgh.. Pa. 15212
Alcolac.lnc, 344U Fairtiek) Rd. Baltimore. Md. 21226
Aldon Company. The. 3410 Sunset Ave, Waukegan. Ill, 60085
Alemite I Instrument Div, Stewart Warner Corp, 1B26 Uiversey
Pkwy.. Chicago. Ill. 60614
Allegheny Ludlum Steel Corp. 2420 Oliver Bldg, Pittsburgh, Pa,
15222
Alien-Bradley Co. 1201 S Second SI. Milwaukee, Wis, 53204
Allen & Garcia Co. 332 S Michigan Ave. Chicago. Ill. 60604
Allenlown Pneumatic Gun Co, P. 0. Boi 185. Allentown. Pa, 18105
Allied Chemical Corp, Industrial Chemicals Div. P.O. Boi 1139R.
Mornslown.. N J. 07960
Allied Steel & Tractor Products. Inc, 5800 Harper Rd, Solon. Ohio.
44139
• Allis-Chalmers. PO. Boi 512. 1125 S. 70th St.. Milwaukee. Wis,
53201
Allis-Chalmers. Crushing & Screening Equipment. P.O. Bu* 2219.
Appleton. Wl. 54911
Allmand Bros, Inc W Highway 23. Holdrege. Neb, 68949
A1MEG P.O Boi 11430. Kansas Cily. Mo, 64112
Alnor Instrument Co, 7301 N. Caldwell Ave. Niles, ill. 60648
Alpine Equipment Corp, P.O. Boi 106. 140 N Gill SI, State Col-
lege. Pa. 16801
Allen Speed Reducer Div., Allen Foundry 4 Machine Works. Inc. P.
0 Boi 550. Lancaster. Ohio. 43130
• American Air Filter Co. Inc.. PO Bo. 1100. Louisville. Ky, 40201
American Alloy Corp. Pyramid Parts Div, 3000 E 87th St, Cieve
land. OH. 44104
American Alloy Sled. Inc. 2070 Steel Or, Tucker. GA. 30084
• American Commercial Barge I me Co, P. 0 Boi 610. Jetlersonville.
Ind, 47130
American Crucible Products Co.. 1305 Oberim Ave. loram. Oho,
44052
American Cyanamtd Co. Industrial Chemicals & Plastics Div, Berdan
Ave.. Wayne. N J. 07470
American Hoist t LYrrick Co.. 63 South Robert St. Si Paul. Minn.
55107
American Industrial Leasing Co, 201 N Wells 51, Chicago. III.
60601
American logging Tool Coip, 302 N Main SI fvarl. Mich, 49631
American Meter Div. Singer Co, The. 13500 Phiiinont Ave, Phila-
delphia. PA. 19116
American Mmeihem Corp, P.O Boi 231. Coraopolis. Pa. 15108
• American Mine Door Co. Boi 6028. Station B, Canton, Ohio, 44 706
American Mine Supply Co, 404 Frick Uldg, Pittsburgh, Pa. 15219
American Optical Corp. 14 Mechanic Si, Soulhbridge.. Mass,
01550
• American Poctam Corp, 3401 Tidewater Trail, fredencksbmg. VA.
22401
• Amencan Putvi-M/er Co I?49 Ma;Klmd Avenue St Louis Mo,
63110
Amencan Rtctilin Coip, 15th Ave. College Poml. NY 11356
American StamiN.I !i«lu\irul Products Div. 81II Tirtnun Ave.
Dearborn. U,,l,. 4BIJ6
• American Tuciui Iq.np Co. P 0 Boi 1226. Oakland. Caul. 94004
American VM. Inc. ?b6 Welsh Pool Rd. Umville. Pi 19353
Amerind MacKini,' Inc. Bo. 111.1'jrker lonl. P.v 19457
Amclek. Cist Million. Ill, 61244
Amoco Oil Cumpriiiy .'(.K) L Randolph Di. Chicago, ill. 60t>01
Amoco Metal Div Annnu I'lllitiuigh Corn. I'D Bo. MKI4 (Vpl
I7J.V MilMiiAiw. Wis 51201
• Amsco Div. Abei Corp. 389 E 14lh SI. Chicago Heights. III.
60411
41 Anaconda Company. Wire and Cable Div, Greenwich Dike Park 3.
Greenwich. Conn, 06830
Anal/tical Measurements. Inc . 31 Willow St. Chatham. N J, 07928
Anchor Conveyors Div, Standard Alliance Indus. Inc. 6906 Kmgsley
Ave. P 0 Boi 650. Dearborn. Ml. 48121
Anchor Coupling Co . Inc, 342 N, Fourth Si. Libertyville. Ill. 60048
Anchor/Darling Valve Co. 24747 Clawiler Rd. Mayward. CA.
94545
Anderson Eleclnc Corp. 801 455. Leeds. Ala. 35094
Anderson Mavor (USA) Ltd. 301 Progress St. Cranberry Ind Park
Mienopte. Pa, 16063
Anderson Power Products, Inc.. 145 Newton St. Boston, Mass.
02135
An.iler Bros. 4711 Goll Rd . Skoktt.. Ill. 60076
Annier Mine I Smelter Supply. 5040 E. 41 si St. Denver. Colo.
80216
Ansul Co. The. 1 Stanton St. Mannetle Wis 54143
Apache Powder Co. P 0 Boi 700. Benson. Am. 85602
Applied Science, Boi 158. Valencia. Pa. 19059
Aquadyne.Div olMolpmco.Inc.26?VreelandAve,Palerson.N. J
07513
• Armco Steel Corp, Product Into, 703 Curtis Si, MOdielown. Oho.
45043
• Armstrong. Bray I Co. 5366 Northwest Hwy Chicago. Ill. 60630
Armstrong Bros Tool Co. 5200 W Armstrong Ave. Chicago III
60646
• Aro Corp . The. One Aro Center. Bryan. Ohio. 43506
Anograph Inc., 529 S 7lh Si, Minneapolis Minn. 55415
Asbury Industries. Inc. 4351 William Penn Hwy. Murrysville Pa.
15668
ASEA Inc. 4 New King St, White Plains, N V 10604
Ashland Chemical Co. P 0 Boi 2219. Columbus. Ohio. 43216
Ashland Oil t Retinmg Co, P 0 Boi 391 Asnland Ky 41101
Associated Research. Inc. 6125 W.Howard SI Chicago. Ill 60648
Aslrosystems. Inc.. 6 Nevada Or. lake Success. NY. 11040
Aroey Products Corp. P 0 Boi 669. Raleigh N C, 27602
Atkinson Armature Works. 116E 1st St. Pittsourg Kan. 66762
Atkinson Dynamics. 10 West Orange Ave So San Francisco. Calil
940HO
• Atlantic Mobile Corp .111 Chesapeake Park Ptaia. Baltimore Md
21220
Atlantic Track t Turnout Co. 270 Broad Si BtoomMd. NJ.
07003
Atlas But 1 Screw Co. Atlas Car & Mlg Ore. 1100 Ivanhce Rd.
Cleveland. Ohio. 44110
Atlas Copco. Inc. 70 Oemarest Or. Wayne. N J
Alias Powder Co. 12700 Park Central Pi Sic 1700. Dallas TX
75230
Alias Railroad Construction Co. PO 80.8 fignir four Pi 15330
A T 0 Inc. 4420 Shewn Rd. Willoughby. Ohio. 44094
Aurora Pump. Unit ol General Signal. 800 Airport Rd. N. Aurora ID
60542
Auslin. J P. Inc. 300 Ml Lebanon Blvd. Pittsburgh Pa . 152 34
• Austin Powder Co. 3735 Green Rd. Cleveland Oho. 44122
Austin Western Div . Clark Equipment Co . 601 N Farnsworth Ave,
Aurora. 111.60507
Auto Crane Co. 9^60 Broken Anew Eip>ess«a«,PO Bo. 4S548
tuna. Oku. 74 KS
Aulo Wrign Int PO Bui 4017 1439 N Emerald Ave. Modesto.
(.al.?53S2
Automat Sprinkler Corp. PO Boi 180. Cleveland. Ohio 44147
Automatic Vulcani/ers Corp. bS5 Madison Ave. New York. N Y.
100??
Automation Products. Inc. 3030 Mai Hoy St. Houston. Teias.
77008
716
-------
B
BalKock & W*,,.. 161 last 42nd 51 . New York. N V. 1001?
Bacr,ir 6. Wamego. Kan.. 66547
Baldwin Belting Inc., 286-288 Spring St.. New York, N Y . 1001 3
Baltimore 4 Ohio R.R. Co . 1 Charles Center - 2 1 si Fl . Baltimore.
lid. 2120!
Banlis-Milter Supply Co. P 0 Boi21 II.Huntmglon.W Va. 25706
Banner Bearings PO. Boi 6040. Stonewall Station. Charleston.
WVa. 25302
Banlam On . Koehrmg Co . 201 Park St , Waverly. Iowa. 506/7
Barter -Greene Co . 400 N Highland Ave . Aurora. III.. 60507
Barter Manufacturing Co. Radac Div. 22901 Aurora Rd . Bedford
Ills. Ohio 44146
Barksdale ControisDiv /DC LAVAL Turbine Inc.. 5 1 25 Alcoa Ave . Los
i.ngeles, Calif . 90058
Barnes Engineering Co., 30 Commerce Rd, Stamford. Conn .
(16904
Barres S. Re.necke, Inc.. 2375 Estes Ave.. Elk Grove Village. III.,
1.0007
Barrrtt. Haenliens Co. Bo> 488. Haielton, Pa.. 18201
Banuries Inc. Bo. 275. Sprague. W.Va , 25926
BASI: Wyandone Corp, Wyandotte. Mich.. 48192
Bauith & Lomb. SOPO Div, 80476 Bausch Si, Rochester. N V.,
4602
Bear Mfg. Corp, 2830 5th Si, Rock Island, III. 61201
Bearcat Tire Co. 5201 w 65th St, Chicago, III, 60638
Sealing Service Co. 500 Dargan St, Pittsburgh. Pa.. 15224
• Beai ings. Inc.. 3600 Euclid Ave, Cleveland. Ohio. 441 15
Beaumont. Edward C , 3236 Candelaria Rd, N £ . Albuquerque.
II M. 87107
Beclman instruments. Inc, 2500 Harbor Bird, Fullerton. Calil,
M2634
Beele Bros . Inc, 2724 Sirth Ave. S . Seattle. Wash, 98006
Beki*rt Steel Wire Corp, 245 Park Ave, New York. N. Y, 1001 7
Belli fonie Insurance Cos.. Sub of Armco Steel Corp, 703 Curtis Si,
Middletown. OH, 45043
Belli vilte Wire Cloth Co, Inc, 1 35 Little Si, Belleville. N. J, 07 1 09
• Bell Helicopter Co. P 0 Bo. 482. Fort Worth, Teias. 76101
Semis Co . Inc . 800 Nonnstar Center, Bo. 84A. Minneapolis. Minn,
!i5402
Berjer Associates. Ltd, P.O Boi 2116. Columbus, Ohio. 43216
Bessemer 4 Lake Erie R R . P 0 Boi'536. Pittsburgh. Pa . 1 5230
Bete Fog Nozzle. Inc , 305 Wells St, Greenfield. Mass.. 01301
Bethlehem Sleel Corp. Martin Town. Bethlehem, Pa, 18016
Bell Laboratories, 4636 Somerlon Rd. Trevose.. Pa, 19047
BIC( Limited. P.O Boi No. 5. 21 Slcomibury St, London WC1B
:iQN. England
BIF. i unit of General Signal. 1 600 Division Rd, West Warwick. R. I,
(12893
Biaci Industries Inc, P. 0 8o« 337-1. Cranford, N.J. 07016
Brddle Co, James G, Township Line & Jolly Rds, Plymouth Meeting.
I'a. 19462
• Big lloise Instruments. Oiv. of Improvecon Corp, 25 Sylvan Rd, So .
Westport. Conn . 06880
Big iiandy Elecinc & Supply Co, Inc, P.O. Boi 2099. South US 23.
(Neville. Ky, 41501
Bigeow-Liptak Corp, 21201 Civic Center Or, Southlield, Mich,
1.8076
indicator Co . Oiv. of Improvecon Corp . 1915 Dove St, Port Huron.
Mien., 48060
• Bird Machine Co, Inc., Neponset Si, South Walpole. Mass, 02071
Birdiboro Corp, Birdsboro. PA. 19508
Bi.br--Zimir.er Engrg. Co, 96 1 Abingdon St, Galesburg. Ill, 6 1 40 1
Blair Mine Supply Inc, P.O. Boi 2182. Clarksburg, W. Va . 26301
Blan-Knoi Equipment. Inc, P. 0. Boi 11450. Pittsburgh. Pa,
5238
Bofcrs America. Inc, 1075 Edward St . Linden. N. J, 07038
Bogi;ess. 6 L , Co.. Mine Development Group. 80 1 Grant St, Denver.
Colo, 80203
Bonded Scale & Machine Co, 2 1 76 So Third Si . Columbus. Ohio.
'.3207
Boston Industrial Products Div, American Biltrite Inc, P. 0. Boi
1071. Boston. Mass.02103
Boston Insulated Wire & Cable Co, Bay St, Boston.. Mass . 02 1 25
Bostrom Div. UOP Inc, 133 W. Oregon Si, Milwaukee. Wise,
S320I
• Bow-lilCo.rio.470. 101 8 Boylan Ave. S E.Canton. Ohio. 44701
Bow nan Distribution. Barnes Group. Inc. 8SO E 72nd St. Cleve-
lind Ohio. 44103
Bov 58. iili lake City. UI. 84 1 10
Brad Harrison Co . 600 I Pla.nluld Rd . LaGrjnuf, III 60525
Srantoro W...tti.»i Co. lrn! Oiv of Ek?clioMeth;lnK-y lm . I'jOJonn
Ooonry |li . N« Bnlain. Conn. 06051
RndirstNir l.if Co ol Amwica. Inc . JlbO W 190 Si . loirpnco.
l. it. OiV,i>>l
'IT iV llcl I 1 chonw, Kv.ituMn I lino k,i. lokyo.
• Hiid.vi Ain,.i,,.in Corn. Ho> 188. W PitMim. I'l IBMJ
HnMh Jrllirv IVnivnit. Iliv of l>es«ei luiui* SA (UK Drum hi.
' Iwini's IrV.iikv WaMirld. W Yorks. tnguiml
Bulk-ink A ItiMnnRnprfo 10440 lifiilon Ave . Si Louis. Mil.
lUI3.'
BroOvillf loifiinottrt- rtv Pennbro Corp . Steel Blvd Brookvitlr.
i'a.iha:s
Sroim Mining Construction Co . P.O Bo. 1 589. Fairmont. W Va .
!!6554
BioimmgMlg Div Emerson Electric Co, Boi 667. Maysville. Ky,
.11056
Brucmng Bearings. Inc, 3600 Euclid Ave, Cleveland. Ohio. 44115
Bruning Co, P. 0 Boi 81247. Lincoln, Neb, 68501
Brunner & Lay. Inc, 9300 King St, Franklin Park. Ill, 60131
Bru-n Transformers Ltd, P.O. Boi 70, Loughborough. Leicester-
:hire. England, LEI 1 IHN
Buci'rus Blades. Inc, 260 E. Beal Ave, Bucyrus. OH. 44820
Bucvrus-Erie Co, P. 0. Boi 56. S. Milwaukee. Wis, 53172
Budil Co, Plastic Products Div . Polychem Products. Franklin Ave. &
l Irani Sis, Phoeninille. PA, 19460
Buffalo Wire Woiks Co . Inc. PO Bo. 129. Buffalo. NY. 14240
Buliard. E. D Co 2680 BrnlReway. Sausanto. Calif. 94965
Bussmann Mlg Oiv . McGraw Edison Co University at Jeflerson. SI
Louis. Mo. 63107
Byion Jackson Pump Div BOIR Warner Corp. P 0 Bo. 2017-
Terminal Anne., los Angles. Calil. 900bl
CCS Hatfield Mining Products. 12 Commerce Dr. Cranford, N J.
07016
• C 4 0 Batteries. Div ol [LIRA Corp. 3043 Walton Rd, Plymouth
Meeting. Pa. 19462
Cf. Fhrsam. 300 N Cedar. Abilene. Kan. 67410
C-t Power Systems. Combuslion Eng. Inc . 1OUO Prospect Hill Rd .
Windsor. Conn. 06095
C E Haymond'Barlletl Snow. Div Combuslion Engineering. Inc . 4? 7
W Randolph Si. Chicago. Ill 60606
CE Tyler Inc. 8200 Tyler Blvd. Mentor. Ohio. 44060
C F11 Steel Corp, PO Boi la30. Pueblo. Colo. 81002
CM Cham. Oiv Columbus McKmnon Corp. Fremont SI, Tonawanda.
N Y, 14150
CMi Corp. P.O Bo. 1985. Oklahoma City. OK. 73101
CR Industries • Chicago Rawhide, 2720 N Greenview Ave. Chicago.
IH.60614
CRC Mley Producls. an Oper ol Crulcher Resources Corp. P. 0. Boi
3227, Houston, Teias, 77001
• CSE Mine Service Co. 2000 Eido Rd. Monroeville. Pa. 15146
Cable Bell Conveyors me, 350 Filth Ave. New York. N Y, 10001
Cabot. Samuel. Inc. One Union Si. Boston. Mass, 02108
CalgonCorp.PO Bo. 1346, Pittsburgh. Pa. 15230
Caliper Corp, Industrial Mktg. Div. 20U Stautter. Naperville. Ill,
60540
Call. Inc, Ray C. PO Boi 8245. So Charleston. W Va. 25303
Calweld. Oiv ol Smith International, Inc. PO. Boi 2875. 9200
Sorensen Ave. Sante Fe Springs. Calif. 90670
CalwisCo.PO. Bo. 3743. Green Bay. Wl. 54303
Cam-Lok Div. Empire Products. Inc, 10540 Chester Rd. Cincinnati.
Ohio. 45215
Campbell. E K Co. 1809 Manchester Traflicway. Kansas City, Mo,
64126
Campbell Cham Co. P 0 Bo. 3052, York. Pa. 17402
CAMRAl Cham Co, inc.. 450Ragland Rd. Beckiey, W Va. 25601
Canton Sloker Corp , P 0 Boi 6058, Canton. Ohio. 44706
Capital City Industrial Supply Co, 544 Broad St, Charleston. W. Va,
25323
Capital Conservation Group. Firth Ave E. & 18m St, Hibbmg. Minn.
55746
Capital Controls Co. 201 Advance Lane, P.O. Bo. 211, Colmar, PA.
18915
• Carborundum Company, P0 Boi 367, Niagara Falls. N. Y , 14302
Card Corp. P 0. Bo. 117, Denver, Colo, 80201
Cardinal Scale Mlg Co. 203 E Daugherty. Webb City. Mo. 64870
* Carman Industries. Inc, 1005 W Riverside Dr, Jeffersonville. Ind,
47130
• CarmetCo,MmetoolOiv,PO.Boi l27.Shmnslon.,W Va.26431
• Carol Cable Co. Div. of Avnet. Inc. 249 Roosevelt Ave, Pawtucket.
R I, 02862
Carver Pump Co, 1056 Hershey Ave. Muscanne, Iowa. 52761
Carus Chemical Co, 1500 8lh St. LaSalle, IL. 61301
Case. Jl, Co. C E Div, 700 Stale Si Racine. Wis, 53404
Cashco. IAC, 540 N 18th Si, Decalur, ill.. 62525
Catalytic. Inc., 1500 Market Si. Centre Square West. Philadelphia.
PA 19102
• Caterpillar Tractor Co. 100 N E. Adams. Peoria. Ill, 61629
Celanese Chemical Co. 1211 Ave. of the Americas. New York. N Y
10036
• Celanese Fibers Marketing Co, 1211 Ave ot Americas. Hew York.
N.Y.10036
Celtile. Inc, 13670 York Rd, Cleveland, Ohio, 44133
Cementation Co ol America, Inc, P. 0 Boi 9. Brampton On!,
Canada. L6V 2K7
Cementation Mining Ltd. Benlley Works. Benlley. Doncaster. Eng-
land. DN5 OBT
Central Engineering Co, Inc, 4429 W. State St, Milwaukee. Wis.
53208
Central Mine Equipment Co, 6200 N. Broadway. St. Louis. Mo,
63147
Central States Industries. Inc, Mining Products Div. Terminal Tower.
Cleveland. Ohio. 44113
• Centrifugal & Mechanical Industries. Inc. 146 President St. SI
Louis. Mo. 63118
Cerro Wire 4 Cable Co. Oiv ol Cerro-Marmon Corp, Nicull and
Canner Sts . New Haven. Conn . 06504
Cerro Wire i Cable Co (Maspeth) 5500 Maspcth Ave. Maspelh
N Y.11378
• Certain-Teed Products Corp. Pipe & Plastics Group, Boi 860 Valley
lorue. Pa. 19482
Certified Welding Service's Inr. [hawei F. Stanalurd. W Va. 2592 7
Cham Systems.!).« cfK K C.nlr. 4(o Inc.I'd Bo. 126 Spring-
Mil. Va . i'.'I'iO
Challenge Cook Hi.n . Inc I •>•!.' I I C.alr Avr Industry Calil
11745
Chratrum I (r\ Soil, hin( llovii p Co . 4 /DO Ciillpndfn l)i . I inns
v.llp. Kt. 40.'.'1
Chnwlion 11"!' Ill) Wni krr 111 . Clmauii. Ill. 60SOI
ClipMirlic.nCUi|i.Wiilit.iil|l>ra(liiilv. 111 I Wiiki'i L)i.Owiito III
1,0601
Chrvtnlon. AW Cnnituny. Mulillrvi ImliiMnal I'ark Hi 93
Slonehnm. M.INV 02180
Chicago PniMiiulii tquipnu-nt Co. 191 Howard St. franklin Pa .
I632J
ChiistensenDnirandl'iodiiclvP 0 Ho.387. 193'S.3rdW Sail
lake City. I li..11 Hal 10
• Chromalloy.Sliunklll.il,-Oiv. 1460 Auto Ave .Pt) Boi43I.Bucy
rus. Ohio, 44ft.'(j
• CIBA GEIGY Corp. 1'H* Systems Dept. 9800 Northwetl Freeway.
Suite 201. Houston. Teias. 77018
• Cincinnati Mine Machinery Co. 2980 Spring Grove Ave, Cincinnati
Ohio, 45225
• Cincinnati Rubber Mlfi Co, Div. ol Stewart-Warner Corp, 4900
Franklin Ave. Cincinnati. Ohio. 4521?
Cisco Fabricating Co, P 0 Boi 75. Cailmville. Ill. 62626
• CIT Corp, 650 Madison Ave. New York. N Y. 10022
• Cilnens Fidelity Bank 4 Trust Co. Cit.lens Pwd Lau.S'iile. Ky.
40202
Clark Equipment Co. Aile & Transmission D.*-. 324 Dewy St.
Buchanan. Mich 4910'
• Clark Equipment Co Construction Machmei, O.v PO Boi 547.
Benton Harbor. Mich. 49022
Clark Equipment Co. Lima Div. 1046 S Ma.n St. Lima. Ohio
45802
Clark Equipment Co Melroe On . 112 N university Dr. Fargo. N 0.
58102
Claikson Co 735 l.oma Verde Ave. Palo Alto. Calil. 94303
Clayton Mlg Co.PO Boi 5530. EI Monte. Caul 91734
Clayton Mark-Pacilic Valves Oiv ol Mark Controls Corp 1900
Dempster St.. Evansion. II 60204
Cleveland-Armstrong Cwp 1108 S K.ibourn Si. Chicago. III.
60624
Cleveland Wire Cloth & Mlg Co, 35/31 7H|hSl Cleveland. One
44105
Corur d'Alenet Co . Blilg » 7. industry Paik Spokane. Wash .
99216
Colling Hoist Oiv Duff Norton Co P 0 Bo. I! 19 Charlotte N C .
28232
Collins Radio. 400 Culim RO. N E Cedar Ruixls ux 52406
Collyer Insulated Wire Co. 100 Higginson Ave. Lincoln R I 02865
Coll Industries. Crucible. PO Boi 226 Midland. Pa 15059
Columbia Steel Casting Co, me, 10425 N Bioss Ave. Portund.
Ore. 97203
Combustion Equipment Associates, me 555 Madison Ave. New
York., N Y, 10022
• Commercial Shearing. Inc .1775 Logan Ave Youngstown, Oha.
44501-
Commercial Testing & Engmeenng Co, 2 28 N La Sane Si, Chicago.
HI.6060I
0 Communication & Control Eng Co Ltd, Park Rd. Caiverton. Not-
tingham England
CompAir Construction & Mining Ltd. Camoorne. Cornwall. England.
TRI4 80S
Compton Electrical Equipment Corp. 720 ISlh St W • Boi 285.
Huntmgton. WV. 25707
Computer Assistance Co, 505 Maple lane. Sewickley. Pa. 1514 3
Concrete Equipment Co. Inc. P 0 Boi 430. Blair. NE. 68008
Cone Dnve Gears. A Unit ol Ei-CellO Corp. P 0 Boi 272. Traveru
City. Mich. 49684
Connecticut Hard Rubber Co, Sub ol Armco Swd Corp. Boi 1911.
New Haven. Conn. 06509
Conneilsville Corp. 120S Third. Conneliswlie. Pa. 15425
Connors Steel Co. PO Boi 118, Huntmgton. W Va. 25706
Conrac Corp. 330 Madison Ave. New York. N Y. 10017
Consolidated Railway Corp. 1542 Sri Penn Center. Philadelphia.
PA 19103
• Continental Conveyor & Equipment Co. P 0 Bo. 400, WmMd. Ma .
35594
Continental Oil Co. P 0 Boi 2197. Houston, lei, 77001
Continental Rubber Works. Sub ol Continental Copper 1 Sled Indus-.
tries. Inc. 2000 Liberty St. Erie. Pa. 16512
Contractors Warehouse Inc.. 1660 No Fort Myer Or, Arlington Va.
22209
Control Concepts. Terry Or. Newton. PA. 18940
Control Products. Inc P 0 Drawer 1087. Beckiey. W Va. 25801
Controlled Systems Inc, P 0 Boi 175. Fairmont. W Va. 26554
Conveyor Components Co. 3640 Milwaukee. LMeport, Midi.
48060
Conwed Corp. Environmental Products Oiv. 2200 Hgixrest W. SI.
Paul. MM. 55113
Coordinated Industries. Rd » 2 Flaugherty Run Rd, CoraopoH. Pt.
15108
Coppinger Machinery Servne. P 0 Boi 89. BluetwU. W Va. 24 701
Corhan Refractories Co. Div of Coming Glass Works. 1600 W Lee
St. Louisville. Ky. 40210
Costam Mining Ltd, 111 Westminster Bridge Rd. London. SEI SEW.
England
Crane Co. 300 Park Ave, New York.. N Y. 10022
• CnsafulliPumpCo.inc,Boi 1051. Glendrve. Mont. 59330
Crosby Group. 2801 DavnonRoad. P 0 3128. Tulsa. OUa. 74101
Crouse Hinds Co. Wolf & 7th North St. Syracuse. N V . 13201
Crown Iron Worts Co, P.O Bo. 1364. Minneapolis. Mmn. 55440
Cummins Engine Co, Inc. 1000 5th St. Columbus Ind. 47201
Curry Manufacturing Corp, P. 0 Boi 618. Glade Soring. Va,
24340
Cushman-OMC-Lincoln PO Boi 82409. 1401 Cushmln Or, Ul-
coin. Neb. 68512
Culler-Hammer. Inc . 4201 N. 27lh Si. Milwaukee. Wii, 53216
Cyclone Drill Co. Orrville One. 44667
• Cyclone Machine Corp. P 0 Boi 39. Scon Depot. W. Va. 25S60
Cypher Co. The. 1201 Washington Blvd. Pittsburgh.. Pa. 15206
• Cyprus Wire I Cable Co, 421 Ridge Si, Rome. N Y . 13440
D A I ubricanl Co Inc . 1331 W 29lh Si. Indianapolis Ind 46208
OAP Inc , 5300 Huberville A« . P 0 Bo. 27 ?. Dayton. Oho. 45401
0 P Way Corp. P 0 Bo. 09336. Milwaukee. Wise 53209
I O.inj Corp. Spicer Universal Joint Div. P 0 Bo. 986. Toledo. Ohio.
43696
IMiwIs C R Inc 3451 E'licolt Center Dr i Itaolt City. Md 21043
Daniels Company. Ihe. Route 2. Bo. 203 Bluelield. W Va . 24701
Dut Irurk Company. P 0 Bo. 321 Kansas City Mo . 64141
hji.orth Co. Tower Lane. Avon. Conn 06001
LUvcy Compressor Co. 11060 Kenwood Rd. Cincinnati. Oho.
45?42
I Davey Rousselle. Drill Rig Div. 2310 W 7Blh Si Chicago. III.
60620
Davis Instrument Mlg Co. 517 E 36lh Si Baltimore Md . 21218
OavisJ I.Associaies.lnc.7900WestparkOr.Sle 915. McLean.
Va.22101
Davis. John & Son (Derby) I Id. 20 Aitreton Rd Derby. DE2 4AB.
England
Dayco Corp. Rubber Producls Oiv. 333 w 1st Si Dayton Ohio.
45402
Dayton Automatic Stoker Co. Ill Deeds Ave P 0 Boi 255, N.
Dayton Station. Dayton. Ohio. 45404
Dean Brothers Pumps. Inc, P.O Boi 68172. Indianapots. IN.
46268
Dean Witter t Co. Inc , 130 Liberty St. New York, N Y . 10006
Deere & Co. John Deere Rd . Moline. ». 61265
Deister Concentrator Co Inc. The. 901 Glasgow Ave. Ft Wayne.
Ind 46801
717
-------
Deister Machine Co.. Inc.. P.O. Box 5168. Fl Wayne. Ind, 46805
Oelavan Electronics. Inc.. 14605 North 73ri St. Sconsdale. Kia..
84260
Delavan Mfg. Co, Grand A*. & 4th St., West Des Momes, tows.
S0265
Delta Wire I Cable Co.. US? W. Diverse/ Pkwy, Chicago. III..
60614
DCMAG lauchhammer. 7041 Werbung. Forststrasse 16. 4000
Dusseldorf 13. Fed. Rep. ol Germany
Deron R & 0 Co.. Inc.. P.O. Boi 603. Morgantown. W Va.. 26505
Derrick Mlg Co, 568 Duke Rd, Buffalo. NY. 14225
DESA Industries. A Unit ol AMCA Intl. Corp., 25000 S. Western Ave..
Park Forest. Ill. 60466
l) Detrick. M. H, Co, 20 N Wacker Or, Chicago, III, 60606
Detroit Diesel Allison Div. Generil Motors Corp, 13400 W. Outer
Or. Detroit. Mich, 48228
Deuti Corp, 7585 Ponce de Leon Circ, Atlanta. Ga, 30340
DeZurik. a Unit of General Signal. Sartell, MN. 56377
Diamond Cham Co, 402 Kentucky Ave, Indianapolis. Ind.. 46225
Diamond Crystal Salt Co, 916 S. Riverside Are.. St. Clair. Mich,
48079
Diamond Tool Research Co, Inc.. 345 Hudson St., New York. N. Y,
10014
Dick Inc.. R. J, P.O. Bo> 306, King ol Prussia. Pa, 19406
Dico Co, Inc.. 200 S W. 16th St.. Des Manes. IA. 50305
Difco. Inc.. Bo. 238, Findlay. Ohio. 45840
Dings Co, Dynamics Group. 4742 W. Electric Ave, Milwaukee. Wis,
53219
Dings Co, Magnetic Group, 4742 W. Electric Ave, Milwaukee.. Wis,
53219
Diversified Electronics. Inc.. 119 N. Morton Ave, Evansville, Ind.,
47711
Dine Bearings, Inc., 3600 Euclid Ave, Cleveland. Ohio, 44115
Diion Valve I Coupling Co, KRM BWg, 800 High St.. Chestertoirn.
Md, 21620
Dodge Div, Reliance Electric Co, 500 So. Union St.. Mishawaka. Ind,
46544
Dominion Engineering Works ltd, P.O. Boi 220. Montreal. Que,
Canada. H3C 2S5
Donaldson Co.. Inc.. P.O. Boi 1299 (1400 W. 94 St.). Minneapolis.
Minn, 554,40
Dorr-Oliver Inc.. 77 Havemeyer La, Stamford. Conn. 06904
Dorr Oliver Long, Ltd.. Orillia. Ontario. Canada
Dosco Corp, 740 Vista Park Dr.. Pittsburgh. Pa, 15205
« Dover Conveyor 1 Equipment Co, Inc.. Boi 300. Midvale. OH.
44653
Dow Chemical Co, 2020 ADOotl Rd. Center. Midland. Mich, 48640
Dow Coming Corp, Midland. Midi, 48640
• Dwell Div. ol the Dow Chemical Co, P.O. Boi 21. Tulsa. Okla,
74102
• Dowty Corp, Progress SI, Cranberry Industrial Park. ZeNenocJe. Pa.
16063
Dravo Corp, One Oliver Pla». Pittsburgh. Pa, 15222
Dresser Industries. Inc.. Crane i Hoist Operations. W. Broadway.
Muskegon, Mich.. 49443
Dresser Industries. Inc. Industrial Products Div, 900 W Mount St.
Connersnlle. Ind. 47331
Dresser Manufacturing, Div. Dresser Industries, Inc.. 450 Fisher
Ave.. Bradford. Pa, 16701
Dresser Mining Services & Equipment Oiv., PO. Boi 24647. Dallas.
leiav 75224
Drill System! Inc.. P. 0 801 5140. Station "A". Calgary. Alberta.
Canada, T2H 1X3
Duron Co., Inc., The. 147 E. Stcond St., Mineola. N. Y, 11501
Duff-Morton Co.. P. 0 Boi 1719. Charlotte. N. C. 28232
e> du Pont de Nemours. E I. & Co. Inc.. 1007 Market St.. Wilmington.
Del.. 19898
Dupte> Mill & Mfg. Co., 415 Sigtor St.. Boi 1266. Sprmglield. Ohio.
45501
Duquesne, Mine Supply Co.. 2 Cross SI, Pittsburgh, Pa, 15209
Durakool. Inc.. 1010 North Main St. Elkhart. Ind, 46514
Durei Products, Inc.. Natl. Wire Cloth Div., Luck. Wise, 54853
Duriron Co, Inc.. The. 450 N. Findlay St, Dayton. Ohio. 45404
Dynei Oiv, Applied Power Inc.. 770 Capitol Or, Pewaukee. Wis..
53072
Dyson. Jos, & Sons Inc.. 53 Freedom Rd, Pairwsville. Ohio. 44077
Eagle Crusher Co, Inc.. Rt 2. Boi 72. Galon. Ohio, 44633
• Eagle Inn Works. 129 Holcomb Ave, Des Manes, IA. 50313
East Penn Mlg. Co, Lyon Station. Pa, 19536
Easton Cai I Construction Co, Holly 4 Liberty Sis, Easton. Pa,
18042'
Eaton Corp. World Headquarters. 100 Ereview Plaza. Cleveland.
Ohio. 44114
Elton Corp, Ante Dtv.. 739 E. 140 St., Cleveland. Ohio. 44110
Eaton Corp, Forestry & Construction Equipment Div, Troian Circle.
Batavia. N Y, 14020
Eaton Corp, Hoisting Equipment Div. Hwy 1. North, Forrest City.
Ark, 72335
Eaton Corp, Industrial Drives On, 9919 Clinton Rd. Cleveland.
Ohio. 44111
Eaton Corp. Transmission Div. 222 Mosel Ave. Kalamaroo, Mich ,
4900)
Economy Fust Div. Federal Pacihc EkK Co. 2070 Maple St, Oes
Plamevi, 60016
Edmom-Wihon. Div ol Becion. Dickinson & Co. 31 >2 Walnut St.
Coshonon., Ohio. 43812
todwflAnvmca tap. Manor Oak Bldg « 1. 1910 Cochran Rd.
Pmsburfti. Pa. 15220
a) EimcoMmmgMachinery.EnviroMchCorp.PO Boi 1211 SaltLake
City. UT. 84110
Electric Machinery Mfg Co, 800 Central An, Minneapolis. Minn.
55413
Electric Products Div, Portec Inc.. 1725 Clarkstone Rd, Cleveland.
Ohw.44112
Electro. 15146 Downey Ave, Paramount. CA. 90723
Electntacl 340? Rose Ave, Octan. N.J.. 07712
Electro Lite Battery Co, 1225 East 40lh St, Chattanooga. Tenn,
37407
• Electro Switch Corp, King Av«. Weymouth. Mass, 02188
El-Jay. Inc.. P.O Bo. 607. Eugene. On, 97401
Ch*mic"s Corp- 5 8< ELMAC Corp, P.O Boi 1692, Munlington. W. Va ,2571?
Emaco Inc.. 111 Van Riper Ave. Elm wood Park. N.J, 07407
Energy Packaging, Inc., P.O Bo» 22. Virginia. MN. S5792
ENERPAC. Div. ol Applied Power Inc.. Butler. Wis, 53007
English Drilling Equipment Co I td. Lmdley Moor Rd, Hudderslield
HD3 3RW. Yorkshire, England
Ensign-Bickford Co, The. P 0 FJoi 7 Simsbury, Conn, 06070
Ensign Electric Div, Harvey Hubbell Inc. 914 Adams Ave, PO Boi
820. Huntmgton. W. Va.25712
Enterprise Fabricators. Inc. Boi 151. Bristol. Va, 24201
Enloleter Inc. P.O Boi 1919. New Haven. Conn. 06509
Environeermg. Inc. 7401 N Hamlin. Skokie. Ill. 60076
Envirei. Inc, 1901 S. Pranie. Waukesha. Wl. 53186
Enviro-Clear. a Div. ol Amstar Corp, Readmgton Rd. & Industrial
Pkwy. Somerville, N J, 08876
Environmental Control Systems. Inc, P. 0. Bon 167. Gallaway.
Tenn, 38036
Environmental Equip. Div. FMC Corp . 1800 FMC Or. West. Itasca.
IL. 60143
Envirosphere Co. 21 West St, New York. N.Y, 10006
Envirotech Corp, Etmco BSP Div, 669 W. 2nd South. Sail Lake City.
Utah. 84110
Eplmg Mlg. Co, Inc . P.O. Bo< 756. Grundy, Va, 24614
E-Power Industries Corp, 211 Mississippi. Boi 2040, Wichita Falls,.
Ten.. 76307
•j Equipment Corp ol America. Boi 306, Coraopolis, PA. 15108
Equipment Mlg Services. Inc. RD 2. Boi 70, Harmony. Pa, 1603?
Erico Products. Inc. 34600 Solon Rd, Solon, Onw, 44139
• Eriei Magnetics. 381 Magnet Or Erie. Pa, 16512
• ESCO Corp, 2141 N W. 25lh St, Portland. Ore, 97210
• Euclid. Inc, Sub. ot While Motor Corp, 22221 Sl Clair Ave, Cleve
land.. Ohio, 44117
Eulectic Corp, 40 40' 172nd St, Flushing NY. 11358
Everson Electric Co, PO Boi 2668. Lehigh Valley. PA. 18001
Eicoa. Inc, 11441 Willows Rd, Redmond. Wash, 98052
Eiide Power Systems Div. ESB Inc. Rising Sun and Adams Ave,
Philadelphia, Pa, 19120
Eiion Co, U.SA. P. 0 Boi 2160. Houston. In 77001
FAG Bearings Corp. Hamilton Ave. Stamlord. Conn. 06904
FMC Corp. Agricultural Machinery Div.. 5601 E Highland Ave,
Jonesboro. Ark. 72401
FMC Corp, Bearing Oiv, 7601 Rockville Rd. Boi 85. Indianapolis.
Ind. 46206
FMC Corp. Chain Div, 220 5 Belmonl. Boi 346B. Indianapolis. Ind,
46206
FMC Corp, Crane 4 Eicavator Div., 1201 Siith St, S W, Cedar
Rapids. Iowa. 52406
FMC Corp, Drive Oiv, 204 5 W. Hunting Park Ave, Philadelphia. Pa .
19140
FMC Corp. Link-Belt Material Handling Systems Div, 3400 Walnut
St, Colmar. Pa, 18915
FMC Corp, Material Handling Equipment Div, 708 Leiington Ave,
Homer City. Pa, 15748
• FMC Corp, Mining Equipment Oiv. Drawer 992. Fairmont. W. Va,
26554
FMC Corp. Pump Div, 2005 Northwestern Ave, Indianapolis.. Ind,
46208
FMC Corp, Steel Products Div, Boi 1030, Anniston. Ala, 36201
Fabreeka Products Co. P 0. Boi F/1190 Adam* SI, Boston. MA.
02124
• Fabricated Metals Industries. Inc, P.O. Boi 8336. Roanoke, Va,
24014
Fabn Valve. P.O Boi 4367. Portland. OR. 97208
Fatnir Bearing Div ol Teitron Inc, 37 Booth St, New Britain. Conn,
06050
• Fagersta. Inc, rt 2 Henderson Dr, W Caldwell. N J. 07006
Failing. George E, Co. A Div ol Azcon Corp. 2215 S Van Buren.
P.O Boi 872. Enid.Okla. 73701
Fairbanks Co. The. 2 Glenwood Ave, emghamton. N. Y. 13902
Fairbanks Morse Engine Div, Colt Industries. 701 Lawton Ave, Be-
toil. Wis. 53511
Fairbanks Weighing Div, Colt Industries. 711 E. St. Johnsbury Rd,
St. Johnsbury,. VI, 05819
0 Fairchild. Inc, P. 0. Boi 890. Beckley, W. Va, 25801
Fairfield Engineering Co, 324 Barnhart St, Marion. Ohio, 43302
Fairmont Supply Co, Boi 501. Washington. Pa, 15301
• Falk Corp, The. Boi 492, Milwaukee. Wis, 53201
Farrell-Cheek Steel Co, 706 Lane St, Sandusky. Ohio. 44870
Fastener House. Inc, 2231 Saw Mill Run 8lvd. Pittsburgh. Pa.
15210
Fate-International Ceramic & Processing Equipment, Div. ol the Fate-
Root-Heath Co, a Banner Co, Bell 4 High Sis Plymouth. Ohio.
44665
• Fate-Root-Healh Co. Plymouth Locomotives Div. Autolilt Ind. Trucks
Oiv, Bell & High sts. Plymouth. Ohio. 44865
Federal Metal Hose Corp P. 0 Boi 548. Pamesville. Ohio. 4407 J
Federal-Mogul Corp .PC Boi 1966. Detroit. Mich . 48235
Federal Supply & Equipment Co. Inc. Bo< 127, 4000 Parkway
Lane. Milliard Ohio 43026
FMCO International. Inc. 3913 Algoma Rd. Gmn Bay. Wl. 54 301
Femco Div, Gullon Industries. Inc. M 0 Boi 33. 2000 Bethel Dr.
High Pant. NC. 27261
• Fennei America Ltd . 400 S asl Main Sl. Middlelown. Conn . 064 5 7
Fenner. JH 4 Co. I id Marfleet Hull. Yorkshire, tngland. HU9 5RA
Ferguson. H K. Co. One tr«v«w Plan. Cleveland. Ohio, 44114
Fetmont Div Dynamics Corp ot America. 14 I North Ave. Bridge-
port. Conn . 06606
Ferro Tech. Inc. 1271 Banksville Rd. Pittsburgh. Pa. 15216
• Fiat-Allis Construction Machinery. Inc .P.O Box 1213. Milwaukee.
Wl. 53051
Fiberglass Resources Coru Motor Ave , Farmmgdale. N V , II 735
Fibre-Metal Products Co. Bin 248 Concoroville. Pa. 19331
Fidelity Electric Co ii.c J12 No.th Arch St.. Lancaster. Pa. 17604
Fil-T-Vac Corp, PO Bo, .'7451. Icmpe. Am, 85282
Finn Equipment Co. 2525 Duck Creek Kd. Cincinnati. Ohio. 45206
Fire Protection Supplies Inc.. 501 Mercer Sl. Princeton. W Va.
24740
•Firestone Tire & Rubber Co. 1200 Firestone Pkwy Akron. Ohio
44317
• firit Colony Corp, PO Boi 296. Grrent 4 Acme Sis. MlnelU.
Ohio. 45750
Firstmark Morrison Inc. 107 Delaware Ave. Buffalo. N Y. 14202
•J) Firs! National Bank ol Maryland. Energy Resources 0>v. 25 S
Charles SI. Baltimore. Md .21202
Fisher Controls Co. PO Boi 190. Marhsalllown. IA. 50158
F.sher Scientilic Co. 711 Forties Ave. Pittsburgh. Pa. 15219
Flat Top Insurance Co, P 0 Boi 439. BluelieW.. W Va. 24701
• tetguard, 8204 Elmbrook. Suite 250. Dallas. Tei. 75247
Fletcher. J H.&Co, P 0. Boi 2143. Huntington, W Va. 25722
Fletcher Sutclitle Wild. Lid, Horoury. Waketeld. Yorkshire. England
Heiaust Co Div ol Catlahan Mining 11 Chestnut Sl. Amesbury.
MA. 01913
• Fle.ible Steel Lacing Co. 2525 Wisconsin Ave. Downers Grove. Ill.
60515
Flenble Valve Corp, 9 Empire Blvd. South Hackensack. N J. 07606
Fleio Products. Inc. 24864 Detroit Rd. WesiUke. Ohio. 4414S
Fleiowall Corp. Boi 156. Kew Gardens. NY 11415
Flood City Brass 4 Electric Co, Messenger 4 Elder Sis. Johnstown.
Pa.15907
• Flowers Transportation. Inc. PO Boi 1588. Greenville. Miss,
38701
Fluid Controls Inc. 8341 Tyler Blvd. Mentor. Oho. 44060
Fluidnve Engineering Co ltd. Flurinve Works. Worton Rd. Islewonh
Miocuewi England. I276EH
Flygt Corp .129 Glover Ave . Noraalk, Conn . 06856
Foote Mineral Co, Route 100. Eilon. Pa. 1934)
Ford Div ol Ford Motor Co. Rotunda Dr at Southlield. Dearborn.
Mich, 46121
ford Steel Co. 2475 Rock Island Blvd. Sl Louis. Mo. 63043
• Ford Tractor 4 Implement 2500 E Maple Rd. Iroy. Mich. 48064
formsprag Co . 23601 Hoover Rd . PO Bo. 778. Warren. Men .
46090
v Fort Pitt Steel Casting. 200 25th St. McKeesport. Pa. 15134
Foster. LB. Co. 415 HoMay Dr. Pittsburgh. Pa. 15220
Foiboro Co. The. 36 Neponset Ave, Foiboro. Mass. 02035
Fraier 4 Jones. Boi 1155. Syracuse. NY. 13201
Frednk Mogensen AB. Boi 78. S 544 00 HJO. Sweden
Frick-GaUagfer Mtg Co. The. 201 S Michigan Ave. WeOslon. Ohio.
45692
Frog Switch Mlg Co, East louther Sl. Carlisle. Pa. 17013
Fruehaul On . Fruehaul Corp. 10900 Harpei. Detroit. Mch. 482 32
Fuller Co, A Gati Co. P 0 Boi 29. Calasauqua. Pa. 18032
Fullerton. Hodgart & Barclay ltd. Vulcan Works, Renlrew Rd, Paisley
PA3 4BE. Scotland
GAFCorp. 140W 51 St St. New York. N Y. 10020
GCA Technology Div, Burlington Rd, Bedford. Mass. 01730
GF.C Mechanical Handling Ltd . Birch Walk. Erith. Kent OA8 I OH.
England
CMC Truck t Coach On, 660 So Boulevard. E . Pontiac. Men,
48053
GTE Sylvania Inc. 100First Ave. Wantam. Mass. 02154
G 4 W Electric Specialty Co, 3500 W. 127th Sl, Blue Island. II.
60406
Gai-Tronics Corp., 400 E Wyomssmg Ave. Monhnlon, Pa, 19540
Galigher Co. The. 440 W 8m S. P. 0 Boi 209. Salt Lake City. Utah.
84110
Galion Manufacturing Div. Dresser Industries. Inc. P 0 Boi 647.
Gallon, Ohio. 44833
Gammeter. W F, Co, P.O. Boi 307. CarJu. Oho, 43907
Gardner Denver Co. PO Boi 1020. Denver. Colo. 80201
Garland Mlg Co, Ironton. Mnn. 56455
Gates Engr. Co. 201 N. Kanawha St, Btckley. W Va, 25801
* Gates Rubber Co, The. 999 South Broadway. Derive, Cob. 60217
Gauley Sales. Inc, PO. Boi 308. Gaulty Bridge. W Va. 25085
General Aluminum Smelting Co, PO Boi 11430. Kansas City. Mo,
64112
General Aviation On, Rockwell International. 5001N Rockwell Aw,
Bethany. Okla. 73008
• General Battery Corp. Boi 1262. Reading. Pa. 19603
General Cable Corp, 500 W. Putnam Ave, Greenwich. Conn,
06830
General Electric Co, Carbotoy Systems Dept. Boi 23 7. General Post
OHice. Detroit. Mich, 48232
General Electric Co, DC Motor & Generator Dept. 3001 E. Lake Rd,
Erie. Pa. 16531
General Electric Co. Industrial Sales On, 1 River Rd. Schenectady.
N Y, 12345
General Electric Co. Instrument Products Operation. 40 Federal St,
lynn. Mass. 01910
General Electric Co, Insul Mils. 1 Campbell Road. Schenectady.
NY. 12306
General Electric Co. Lamp Marketing Oepl, Nela Park. Cleveland.
Ohio. 44112
General Electric Co. locomotive Products Dept. 2901 E Lake Rd,
Erie. Pa. 16501
General Electric Co. Mobile Radio Dept. P 0 Boi 4197. Lynchburg..
Va.24502
General Electric Co. Power Circuit Breaker Depl, Section I. 6901
Elmwood Ave, Philadelphia.. Pa. 19142
General Electric Co, Transportation Systems Business Div, 2901 £.
Lake Rd. Erie. Pa. 16501
General Electric Co. Wire and Cable Opt 1285 Boston Ave.
Bridgeport. Conn. 06602
General Electric Co, Wiring Device Product Dept, 95 Hathaway St.
Providence. R 1. 02904
General Electric Credit Corp, Pittsburgh. Pa, 15205
General Equipment & Mlg. Co. Inc, 3300 Fern Valley Rd, Louisville.
Ky, 40213
General Kinematics Corp, 777 Lake Zurich Rd. Barnngton. III.
60010
General Refractories Co, U S Refractories Oiv. 600 Grant St. Pitts-
burgh. Pa, 15219
General Resource Corp .201 S 3'd Sl. Hopkins. Minn. 55343
General Scientific Equipment Co. Limekiln Pike & Williams Ave.
Philadelphia. Pa, 19150
General Splice Ccvp. Boi 392. Croton Dam Rd, Croton Hudson..
N Y. 10520
General Supply & Leasing Co. 64 Kansas Ava. Kansas City. Kan.
66105
General lire & Dubber Co, Inc. One General St. Akron. Ohio.
44309
GenRad. 300 Baker Ave. Concord. Mass .01742
718
-------
0 Giometrics, 395 Java Dr.. Sunnyvalle. Cat. 94086
GEOMIN. Calea Victor* 109, Bucharest. Romania
Gwrge Evans Corp., The. 121 37th Si Molme. Ill 61265
G Ison Screen Co.. P. 0. Bo< 99. Malmta Ohio. 43535
Gobe Battery Div, Globe Union Inc. 5757 N. Greenbay Ave. Mil-
waukee.W.s. 53201
Gobe Salely Products. Inc.. 125 Sunrise PI. Daylon. Ohio, 45407
Gosser, M.. and Sons. Inc.. 72 Messenger St., Johnstown. Pa.
15902
Gilder Associates. Inc, 10628 N.E. 38th PI.. Kirkland. Wash,
98033
Gxxttll Rubber Co.. WMitehead Rd, Trenton. N. J. 08604
Gxxlbary Engineering Co.. 1518-0 So. Norfolk. Tulsa. Okla.. 74120
& woman Equipment Corp, 4834 South Halsted St., Chicago. Ill,
60609
Gxxlncti. B F.. Chemical Co, 6100 Oak Tree Boulevard. Cleveland,
Ohio. 44131
* Sxxfnch, B F.-Engmeered Systems Co, 500 S. Mam SI, Akron.
Oho. 44318
axrtyear Tire 4 Rubber Co, 1144 E. Market Si, Akron, Ohio.
44316
• &)rman-Rupp Co, The, P. 0. Boi 1217, Mansl«ld. Ohio. 44902
Gnuld Inc. Century Electric Div, 1831 Chestnut St. St. Louis. Mo,
63166
Gould inc. industrial Battery Div.. 2050 Cabot Blvd W. Langhome,
Pa, 19047
Giulds Pumps. Inc, 240 Fall St.. Seneca Falls. N. Y, 13148
Giryne Pump Co, East Centre SI, Ashland. Pa, 17921
GiKe. W.R 4 Co, Construction Products Div, 62 Whiltemore Ave,
Cambridge. Mass. 02140
Great Lakes Instruments. Inc, 7552 N. Teutonia Ave. Milwaukee,
Wise. 53209
Green International. Inc. 2015 Grand Ave. Des Momes, Iowa.
50312
•> Greenbank Casl Basalt Eng. Co. Ltd, Gale St.. Blackburn. Lanes.
England
Grecngale Industrial Polymers Ltd, Irwell Works. Ordsall Lane. Sal-
lord MS 4TO. England
Greening Donald Co. Ltd, P.O. Boi 430. Hamilton.. Ont, Canada
Greennlle Steel Car Co, Greenville. Pa, 16125
Gnttolyn Co, Inc, P. 0. Boi 33248. Houston. Te., 77034
Grndei-CWI Distributing Co, 655 Brea Canyon Rd. Walnut, Cal.
91789
Groendler Crusher & Pulwnier Co, 2917 N. Markel St., St. Louis,
Mo, 63106
Qrjner, Div ol Smith International. Inc. Drawer 911. Ponca City.
Okia. 74601
Gull Oil Chemicals Co, P.O Boi 2100. Houston. Te>, 77001
• Gull Oil Corp, Dept. DM. P.O. Boi 1563. Houston. Teias. 7 7001
• Gull States Paper Corp, P.O. Bo> 3199. Tuscaloosa. Ala, 35401
<> Gulkk Dobson Intl. Ltd, P.O. Boi 12. Wigan. Lancashire. England.
WN1 300
Gundlach. T J, Machine Co, Div. J. M j. Industries. Inc, P. 0. Boi
385. Belleville. III.. 62222
Gunson's Sortei (Mineral & Automation) Ltd, Hyde Industrial Es-
tate. The Hyde. London NW9 6PX. England
Gustin-Bacon Div, Aeroquip Corp, P.O. Boi 366. Lawrence. Kan,
66044
Guyan Machinery Co, P. 0 Boi 150. Logan, W. Va, 25601
H
Haoker Instrument) Inc, P 0. Boi 657. fairlield, N J, 07006
Haiiglund 4 Soner. AB. Fack, 891 01 Ornskoidsvik 1,, Sweden
Haun Industries. Mm 4 Mill Specialties. 50 Broadway. New York.
N. Y. 10004
Halecrest Co. Ml Hope Mine Div, Ml. Hope Rd. Ml. Hope. N. J.
07885
Halliburton Services-Research Center. P.O. Boi 1431, Duncan..
Okla, 73533
• Hallite Seals Inc, 1929 Lakeview Or, Fon Wayne. Ind, 46808
Hammer mills Inc. Sub of Pettibone Corp, 625 C Ave. N W, Cedar
Rapids. Iowa. 52405
Hammond. J V Co, N. 1st Si. Spongier. Pa. 15775
Hanco International Div. of Hannon Electric Co. 1605 Waynesburg
Rd, Canton. Ohio. 44707
Hanson. R A. Disc, Ltd, P. 0. Boi 7400. Spokane. Wash, 49207
Hardman inc. Belleville. N.J, 07109
Hardy Plants. 587 Harmony Rd, New Brighton, Pa, 15066
Hardy Salt Co, P. 0. Drawer 449. Si Lous. Mo. 63166
Harmschieger Corp, P.O. Boi 554. Milwaukee. Wis. 53201
Harrington 4 King Perforating. 5655 Fillmore Si, Chicago. Ill,
60644
Haick Mtg Co. P.O. Boi 90. Lebanon, Pa. 17042
• Hai(masters. Inc, 1212 So. Parker Rd. Olathe. Kan . 66061
Ha<*er Sidoeley Dynamics Engineering Limned. Manor Road. Hal-
'ield Herts
Ha>*er S'Cjddey Eiecinc Eiport Lid. PO Boi 20. Loughborough.
•.eics. LEI I IHN. England
Hayjen-Ntios Conilow Ltd, Triumph Rd, Lenton. Nottingham. Eng-
land. NG7 2GF
Haj;n Research. Inc, 4601 Indiana St. Golden Colo. 80401
HB Ktectncal Mlg. Co, P.O Boi 1466. Mansfield. Ohio. 44901
Heal Wnghlson 4 Co. ltd. The Frurage. Yarmon Tees. Stockton.
Cleveland. England. TS17 6V
Heil Process Equipment Co, Div. of Dart Industries Inc.. 34250 Mills
ltd, Avon. Ohio. 44011
Hemh Manulacturers. Inc, 6229 Cratton Rd, Valley City. Ohio.
'14280
• Hdvig Carbon Products. Inc, 2550 N 30th St. Milwaukee Wis
!i3210
• Heir.tdWKll America. Ste. 660. Manor Oak No 1. Pittsburgh. Pa
15220
• Hemlerson Gear Corp, Venetia Rd, Venetia. Pa, 15367
Hrmlnck Mlg Co. Lock Boi 497. Carbondale. Pa. 18407
Hi'mlni Mlg Co. Inc.. P. 0. Boi 919. Mansfield. I a . 7IO.S?
HnmJey Industries Inc . 2108 Joe F«ld Rd . Dallas. Tei. 75229
Hercules Inc. Hercules Tower. 910 Market St, Wilmington. Del.
19899
Hprrjld Mlg Co. 215 Hickory St. Suenton. Pa
Hrwilt-Robins Conveyor Equipment Iliv Lilton Systems. Inc. 270
Passaic Ave. Passaic. N J. 07055
Hrwilt-Robins Div. tilton Systems. Inc, PO. Boi 1481. Columbia.
SC.29202
Hewlett-Packard 815 UlhSt.SW,PO Boi 301,Loveland.Colo.
80537
0 ,Heyl & Patterson. Inc. 7 Parkway Center. Pittsburgh, Pa. 15220
HITCO. Sub ol Armco Sleel Corp, Boi 1097. Alondra Station. Gar
dena. Cal, 90249
Hobart Bros Co. 600 W. Mam SI, Troy. Ohio. 45373
tollman Diamond Products Inc. Tiona & Cedar Sts. Pumsutawney.
Pa, 15767
Holley, Kenney. Scholt. Inc . 921 Penn Ave. Pittsburgh, Pa . 15222
Holmes Bros Inc, 510 Junction Ave, Danville, III, 61832
Hoi] Rubber Co. A Randron Div. P.O Boi 109. 1129 Sacramento
St.. Lodi. Calil. 95240
Homelite Div. Teilron Inc. P 0 Boi 7047. Charlotte. N. C, 28217
Homestead Industries. Inc. PO Boi 348. Coraopolis. Pa, 15108
Honeywell Inc. Process Control Uiv. 1100 Vingmia Dr. Fort Wash-
ington. Pa, 19034
Hossleld Mlg Co. 440 W Third Si, Wmona. Minn, 55987
Houdaille Hydraulics. 537 E Delavan Ave . Buffalo. NY, 14211
Houghton 4 Co. E. F, 303 W. Lehigh Avt'. Philadelphia., Pa, 19133
Howe Richardson Scale Co, 680 Van Houten Ave. Clifton, N. J.
07015
Hoyt Wire Cloth Co. 10 Abraso St. Boi 1577, Lancaster. Pa.
17604
Huber Corp, Div ol A T-0. Inc, 200 No Greenwood 51. Manon, OH.
43302
Hubtnger Co. The, Keokuk. Iowa. 52632
Hughes. L J, & Sons. Inc. 320 Turnpike Rd. Summersville. W Va.
26651
Hughes Image Devices. 6855 El Cammo Real. Carlsbad. Cal.
92008
Hughes Tool Co, P 0 Boi 2539, Houston. lei ,77001
• Hulburt Oil 4 Grease Co. 2200 East Caslor Ave. Philadelphia. Pa.
19134
Hunslet Holdings Ltd. Hunslel Engine Works. Leeds IS 10 1BT. Eng.
land
Huntec (70) ltd, 2 5 Howden Rd. Scarborough. Ont.. Canada. M i.
5A6
Huron Mlg. Corp, PO Bo. 1398, Huron SO, 57350
• Huwood Irwin Co, Boi 409. Irvtm. Pa. 15642
Huwood Limited. Gateshead. tyne 4 Wear. NE11 OLP. England
HYCO. Inc. Sub ol The Weatherhead Co, 1401 Jacobson Ave.
Ashland. Ohio. 44805
Hydraulic Products Inc. P.O Boi 458. Slurtevant. Wis, 53177
Hydreco. A Unil ol General Signal. 9000 E Michigan Ave. Kaiama
too, Mich, 49003
Hydr-0-Matic Pump Div, Weil-McLam Co Inc. Claremonl 4 Baney
PO Boi 327. Ashland. Ohio. 44805
Hy Test Safety Shoes Div International Shoe Co. 1509 Washington
' Ave. SI Louis. Mo. 63166
I
I 4 M Equipment Sales. Inc, R * I. Boi 28M. Bourbon.. Ind .46504
I-T-E Imperial Corp Nornstown Rd Spring House, Pa, 19477
ITT GnnneH Corp, 260 W. Exchange St., Providence, Rl, 02901
in Harper. 8200 Lehigh Ave . Morton Grove. Ill. 60053
in Holub Industries. 413 OeKalb Ave, Sycamore. Ill, 60178
ITT. Industrial * Automation Systems. 41225 Plymouth Rd. Ply-
mouth. Mich . 48170
in Royal Electric. 95 Grand Ave, Pawlucket. R I, 02862
ILG Industries. Div ol Carrier Corp, 2650 N Pulaski Hd, Chicago.
111.60641
Illinois Gear/Wallace Murray Corp, 2108 N. Natchej Ave, Chicago.
Ill, 60635
Impact Rotor Tool Inc, Route 30. E. Irwin. Pa. 15642
• Imperial-Eastman Corp, 6300 W Howard SI. Chicago, III. 60648
Imperial Oil 4 Grease Co. 10960 Wilshire Blvd . los Angeles. Cal,
90024
Independent E«plosives Co, 20950 Center Ridge Rd. Cleveland.
Ohio. 44114
Indiana Steel & Fabricating Co. Rl 286 So. Indiana. Pa. 15701
Industrial Contracting ol Fairmont. Inc . P 0 Boi 352 Fairmont W
Va.26554
Industrial Electric Reels Inc, 1125 Jackson St. Omaha. Neb.
68102
Industrial Pneumatic Systems. Sub of Industrial Contracting ol Fair
monl, Inc . P.O Boi 352. Fairmont. W Va , 26554
Industrial Rubber Products Co, P.O. Boi 2348 815 Court St
Charleston. W Va. 25328
Industrial Steel Co, P 0. Boi 504. Carnegie. Pa. 15106
Inllo Resomelnc Scale Inc, 2324 University Ave, Si Paul. Minn.
55114
• Ingersoll-Rand Co. Woodclill Lake. N I 07675
Inland Steel Co. 30 W. Monroe St. Chicago. Ill. 60603
Insley Mlg, A Unit ol AMCA Inl'l. Corp, 801 N Obey PO Bo>
11308. Indianapolis. Ind, 46201
• International Alloy Steel Div. Curtis Noll Corp, 3917 St Clair Ave
Cleveland. OH. 44114
• International Harvester Co, 401 N Michigan Ave Chicago III
60611
international Salt Co. Clarks Summit. Pa , 18411 '
• Interstate Equipment Corp. 300 Ml Lebanon Blvd . Pittsburgh Pa
15234
Iowa Industrial Hydraulics. Inc. Industrial Park Rd Pocahontas.
towa. 50574
Iowa ManulaclunngCo. 916 !6ihSi.N E. Cedar Hapids, towa,
52402
Iowa Mold Tooling Co . Inc . 500 Highway 18 West. Garner. Iowa.
50438
liathane Systems, Inc. Industrial Park. Ilibbmj. Minn . 55746
Ireco Chemiral\ fn Kenmxotr Bldg. Smle 726. Sail Lake City..
Utah. 84111
livin MrKi'lvy U I In'. P II Hoi 767. In.lnnj. P» , I 5 701
• ISC'.OMIu fn I'u uo> Hd.'O. Kansas Oiy Mo. nil 4
Ilium Climn C. 1'irt W Wn,(lit»o«l. I In.luirit. Ill I.OIJfi
J In. AMKiatia. Inc. 317 7th Avn. SI . Cellar Hnpiui, li.v.i
b/401
labro. Inr . W6 Ogle Si. fbensburg,. Pa . 159.11
Jauger Machine Co 550 W Spring St Columbus Omo 43216
James D 0 Gear Mlg Co. Unit olE< Cell 0 Corp. II40W Monroe
Si. Chicago. Ill. 60607
Janes Manulactunng Inc. 7625 S Howeil Ave. Oak Creek. Wis.
53154
Jarva. Inc. 29125 Hall SI. Solon. Ohio 44139
Jelfrey Mlg Div, Dresser Industries Inc. 912 No. Fourth St. Colum-
bus. Ohio. 43216
Jellrey Mining Machinery Div. Dresser Industries Inc. 953 No 4th
SI, Columbus, Ohw. 43216
Jenkins Bros, 100 Park Ave. New York. N Y. 10017
Jenkins of Retford Lid. Rertord. Notts DM22 7AN. England
Jennmar Corp. P.O. Boi 187. Cresson. Pa. 16630
Jet Lube inc. P 0. Boi 21258. 4849 Homestead Rd. Houston. TX
77026
Jim Bo's Food 4 Beverage Shoppes. P.O Boi 1535. Beckley. W Va.
25801
Johnson Blocks Div, Don R Hinderliter. Inc. 1240 N Harvard. P 0
Boi 4699. Tulsa. Okla, 74104
Johnson Div, Universal Oil Products. P.O Boi 311 B. St Paul. Minn.
55165
Johnson-March Corp. The. 3018 Market St. Philadelphia. Pa.
19104
Johnston-Morehouse-Dickey Co. 5401 Progress Blvd. PO Boi
173. Bethel Pat*. Pa. 15102
Johnston Pump Co. 1775 E Allen Ave Gwndora. Cal. 91740
Johnston Pump Co. Pittsburgh Branch. 17 2 5 Washington Rd. Prttv
burgh. Pa. 15241
JoidMlg Co.lnc.Boi 341.0akwoc« Va 24631
Jones 4 Uughlm Steel Corp, 3 Gateway Center. Pittsburgh Pa.
15263
Jones & Laughlin Sled Corp, Conduit Products McKees Lane. Nrfes,
Ohio. 44446
Joy Mlg Co. Henry W Oliver Bldg. Pittsburgh. Pa, 15222
Joy Mfg Co. Denver Equipment Div. P. 0 Boi 22398. Denver.
Colo, 80222
Joy Mtg. Co, Electncal Products Oept. 338 S. Broadway. New Phila-
delphia, Ohio. 44663
Joy Mlg Co (U.K.) Lid, Burlington House. Chesterfield. Derbyshire
S40 1S8. UK
Joy Service Center. Ov toy Mlg Co. P 0 Boi687.BlueMd.W.Vt.
24701
Judsen Rubber Works. Inc . 4107 W Kmiie SI. Chicago, H. 60624
KG Industries. Inc. 10225 Higgins Rd .'Rosemont. II. 60018
KHD Industneanlagen AC. Humboldl Wedag. Wwsberjstrisse, D 5
Koeln 91. Fed Rup. ol Germany
KW Battery Co. a On olWesttnghouse Electric Corp. 3 5 55 Mown)
SI. Skokie. in, 60076
Kaiser Aluminum 4 Chemical Corp. 942 Kaiser Bug. 300L*eute
Dr. Oakland. CaM.. 94643
• Kaiser Engineers. Inc, 1818 Kaiser Center. 300 Lakeside Dr.. Oak-
land. Cal, 94666
Kalenburn. Or Ing. MaunU KG. 0-5461 Kalenbom near Lw on
Rhine. Germany
Kanawha Mlg Co, P 0 Boi 1786. Charleston W Va. 25326
Kay Ray Inc, 516 W Campus Or. Arlington Heights. I 60004
Keenanftl Co. 2350 Seymour Ave. Cincinnati. Oh». 45212
• Kennamelal Inc.. Mining Tool Group. PO Boi 346. Utrooe. Pa.
15650
Kennedy Metal Products & Buttngv Inc. Jack Boi 38. 200 S
Jayne St. Tiykxvrfte.. Ill. 62568
Kennedy Van Saun Corp Sub. of McNaHy Pmsourg. Dm*. Pa.
17821
Kent Air Tool Co, 711 Lake St. Kent.. Oho. 44240
Kenworth Truck Co. PO Boi 80222. Seattle. Wash, 98108
Kern Instruments Inc, 111 Bowman Ave, Port Chester. N. r,
10673
Kersey Mlg Co. P 0 Boi 151. Bluehekt. Va. 24605 .
Keystone Bolt Co, Sub of Jenmar Corp. 600 Arch St. Cresson. PA.
16630
Keystone Div. Pennwali Corp. 21 4 Lippmcon Sts, Philadelphia.
Pa.19132
Keystone Sieel I Wire. Div ol Keystone Consolidated Industries. Inc.
7000 SW Adams. Peoria. IL. 61641
Kidde. Walter. 4 Co. Belleville Div. 675 Mam Si. Belleville, N j,
07109
Kilborn-NUS. Inc. 600 S Cherry St. Ste 1235. Denver. Co. 80222
Kilo Wate Inc . Boi 798. Georgetown. Te>. 78626
Kinetics. Inc. 1001 So First St, Artesia. N M. 88210
• KnaackMlg Co. 420E. Terra Cotta Ave. Crystal Lake. HI. 60014
Koch Engineering Co. me, 161 E. 42nd St. New York. N1.10017
Kockums Industn AH, Fack. S 261 20 Landskrona. Sweden
O'Koennng. Crane/Eicavator Marketing Div. 780 N. Water Si, Mil
waukee. Wise. 53201
Koehnng Div ol Koehrmg Co. 3026 W. Concocdia Ave, PO Boi
422. Milwaukee. Wis. 53216
Koiborg Mlg. Corp. West 21 St, Yankton. SO. 57078
Komatsu America Corp, 555 California St. Ste 3050 San Fran-
cisco. Cal. 94104
Koppers Co. Inc. 1900 Koppers Bldg. Pittsburgh. Pa, 15219
0 Koppers Co. Inc Metal Products Div. Hardmge Operation. Boi 312.
York, Pa, 17405
Koppers Co Inc. Metal Products Dre. P 0 Boi 298. Baltimore. Md.
21203
Krebs Engineers. 1205 Chrysler Dr. Menlo Park. Calif, 94025
• Kress Corp, 400 Illinois Si. Bnmfield. Ill. 61517
K iron Corp. PO Boi 548. Glasiboro. N. J. 08028
r I 4M Radiator. Inr. 14 14 I 37lh Si Hibumi Minn 55746
l«Hn.u PUIML (.0 . V 1). Hoi 1187. I « i.arl. Md . 4(514
IM«.hCo.540l S Packard Av«. Boi I Cudahy Wis. 53110
Ukr Shore Inc . P 0 Boi 809, Iron Mountain. Mih , 49801
> I aMarche Manulactunng Co. 106 Bradrock O. Des Piwui lit.
60018
Later Alignment. Inc, 6330 28th St. S E . Grand Rapids. Ml. 49506
719
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Lautenstein Mlg Co., 418 S. HoHmon Blvd.. Ashland. Pa.. 17921
Lawnel Corp.. PO. 8o> 206. Btofidd. W. Vs.. 24605
Lawrence Pumps. Inc., 371 Martul St. Lawrence. Mass. 01643
lebco. Inc.. Illinois Oiv.. Hraoy I4E.. P.O. Boi 656. Benton. III..
62812
Lotus International Inc., Bon 2352. Longview. Tei, 75601
Loo Corp.. 3000 Utovoo AVC*. Si. Joseph. Mich. 49085
O lea, A.L.. & Co.. Inc., 1166 Ctowtond Aw. (P.O. Boi 8085), Colum-
but, Otiio, 4 3201
Lesds 6 Northrup Co.. Sumneytoon Pike. North Wales, Pa. 19454
O Lee-Norw Co.. Sub. of InrjertoWtend Co.. 751 Lincoln Am., Char
terfePa.. 15022
Lee Supply Co.. Inc., 130 Lincoln An.. P.O Bo. 35. Charleroi. Pa,
15022
Lchigh Solely Shea Co., 1100 E. Mom St., Endicotl. NY. 13760
Lo Hi Volw & Ceuplma. Hose Products Dw., Porlter-Hannitin Corp,
30240 Lokctend Blvd.. WicMiffo, Oho, 44092
U Roi On., Dmua Induslras, IK., Main & Ruuoll Rd. Sidney. Onio.
45369
Lemon tlccJiino Co, S. Roiiroed St.. Poftogo, Po. 15946
Loithon Wno Ropo Co.. 801 407, St. Jotoph. Mo, 64502
O Lrottwr Amonco. Inc, 4100 Chtttnut A«o.. Drawer 0, Newport
rtiet. Vo.. 23305
O Lightning Industrie. Inc.. 801 Woodswettwr Rd. Kanso» City.. Mo.
64165
Umo Etectnc Co., Inc.. 200 E Chapmen Rd.. Lima. One. 45802
linotei Corp. of Amenta, P.O. Boi 65, Station! Springs, Conn.,
06076
Lincoln Etectric Co.. The. 22801 St. Clair An.. Cleveland. Oho.
44117
Lincoln St. Louts Ki. o) McKal Corp.. 4010 ttoodleltoo Blvd.. St.
Louis. Ko, 63120
Line Pooar Manufacturing Corp., 320 East Williams St., Bristol, Vo.,
24201
Livdy Mlg £ Equipment Co.. P. 0. Boi 338, Glen White, W. Va.,
25849
Loltus, Peter F, Corp. Chamba ol Commerce Bldg.. Pittsburgh. Pa.
15219
logon Corp.. 555 7th Are, P.O. Boi 1895. Huntington, W. Vn,
25719
O Long-Airdoi Co. A Dw. ol me Mormon Group. Inc., P 0 Boi 331. Oak
Hill. W. Va., 25901
Lonrjyeor Co., 925 Delaware St. S.E., Minneapolis. Minn. 55414
Louis Win Dtv. Litton Industrial Products. Inc.. 427 E. Stewart St..
Dopt CA, Mrteou!u», Wis., 53201
Louisvilte £ NasUvte RR, 908 Wen Broadway. Louisville. KY. 40203
Lubrication Eiwtart, Inc.. PO. Box 7128. Ft. Worth. TX. 76111
Luhriplate On.. Fiste Brothers Refining Co.. 129 Lockwood St.. New-
ark. N.J., 07105
Lucas mdustrias. Fluid Powf Dnr.. P. 0. Boi 662.30 Von Nostrand
Aw., Enjtesood. M. J.. 07631
Ludtcr Mtn, Co., 444 So. Henderson Rd., King of Prussia, Pa..
19406
Ludba-Saytor Biro Cbth, On. G.S.I.. 8474 Delport Dr., SI. Louis.
Ko., 63114
Lictan Stcd Co.. W. Lmooin Mrjhwov. Coatesvife Pa.. 19320
Lunionhoima- Co, On. ol Convd Corp.. Sub. ol Coretec Corp., Beet-
man at Wovotjr Ata, Drtannoti. Ohio. 45214
Lysn Ueta Prods. Inc.. P.O. Boi 671. Montgomery. IL, 60507
O3 M Co. 3M Center. SI. Paul. Minn.. 55101
' Jtobscott Supply Co.. Boi 1560. BacWey. W. Va. 25801
Mac Products, Inc.. 60 Pennsylvania A«.. Keomy, NJ, 07032
Mceaoter Engnesrins Lid.. Oadsn Rd.. Doncaster DN2 4SQ. Eng.
lend
MacOonaU Engmeaing Co.. 22 W. Mcdison St. Chicago. Ill. 60602
Ucdiinery Center. Inc.. 1201 S 7th West P. 0. Boi 964. Salt Lake
City, Uteh, 84110
Mcchinoeiporl. 35 Moslolmovskoiu. Moscow M-330. USSR
0 Utx* Trucks. Inc.. Boi M. Allsntown. Pa. 18105
Mamhyte Wire Rope Co., 2931 14lh Aw, Kenosha, Wis.. 53140
Majcc DTV,, Donaldson Co.. 5555 S. Garrwtt. Tulu. Okla, 74145
Mcngonase Sled Forge. Taytor-Wnorton Co.. On. ol Harsco Corp,
2900 William Penn Hujtooy. Eoston, Po., 18042
(taihamMlg. &Belong. 311 W SfegdSL.Manheim. Po.. 17545
Uontosoc Engircarinj Co., D». CtaiitOBOc Co., 500 S 16th St..
Manitowoc. W.s. 54220
Monton Sarvicov Inc., R.O. PI, Boi 307 A. Greensboro, Po, 15338
ttenulccturcrs Equprrent Co.. Tha. 35 Enterprise Dr.. Middtetown,
Ohio. 45042
0 Monutccturers Hcnwar Leasing Corp., 350 Port Ave., Neo York.
MY.. 10022
Marathon Cool Bit Co. Inc, 80. 391. Montnmory. W Va .25136
Morothon Letourmou Co., Longvien On, P. 0. Boi 2307. Longview,
Toias. 75601
Marathon MM Co. 600 Jeffanon. 1900 Marathon Bldg. Houston.
To.., 77002
Mcnalta Concrete Co. P 0 801 254. Moretta. Ohio. 45750
MononCo.Dw.olSyeonCorp.P0 Boi491.Manon.Ohio.43302
O Koran Po«x Srnvol Co Inc, 617 « Centm St.. Monon. 0»«.
43302
UarkEQupmentCo.6033UanchnIcrAw.St Lous.Mo.63110
McrUnd One Wo> Clutch On.. 2um Industrin. (nc . P 0 Bo» 308.
La Grange, lit, 60525
MortJo-Rockoen. On. ol TRW. Inc.. 402 Chand& St. Jamntoan.
N.Y.. 14701
Uarmon Transmodvo Div.. Sanfonl Day Productv P 0 Boi 1511.
KnontUe. Tenn.. 37901
Marquane Katd Prods. Co.. IU5 Galeetnl Dr.. Cleveland. Ohio.
44110
Marsh, E. F., Engineering Co.. 1400 Hantey Industrial Dr.. Si Louis.
MO. 63144
Martin Engrg. Co.. U. S. Die. 34. Neponset.. Ill. 61345
Mamndak) Electric Co., 1307 Hint Ave., OjveUinO, Ohio. 44107
O Massey^FcfRuson Industrial & Construction Mcdunery. P. 0.1500.
Akron. Ohio, 44309
Material Control, Inc., 719 Morton An., Aurora. 111., 60506
O Mameos, Ate W., Enginsaring Co., 555 West 27th St.. Nibbing, MM.
55746
O MATO. P. 0. Boi 70.0-6050 Offenbach (Main) 1.. W. Germany
Mc6ride Industries Inc.. P.O. Boi 94. St. Albons. W. Va., 25177
McDowell-Wellman Engrg, Co.. 113 St. Clair Ave. Hi, Cleveland.
Ohio. 44114
McGra«-Edison Co. Power Svsiems Oiv., P 0. Bo« 440. Canons
burg. Pa.. 15317
McJunkin Corp. Charleston. W Va.
McKee. Arthur G. I Co., Western Knepp E ng. Dw, 2855 Campus Or.
San Maleo. Cal. 94403
McKey Perforating Co,. Inc.. 3033 So. 166th St.. New Berlin, Wis..
53151
n Mclanahan Corp. 200 Wall Si. Hollidaysburg. Pa. 16648
0 McLaughlin Mlg. Co. P.O. Bo> 303. Plamlwki. IL. 60544
McNally Pittsburg Mlg. Corp.. 307 W. Third St.. Pittsbwg. Kan..
66762
Measurement & Control Systems OH , Gulton Industries Inc.. Gullon
Industrial Park. East Greennich, Rl. 02818
Megator Corp. 136 Gamma Dr, Pittsburgh, Pa., 15238
Merkel Forshcda Corp. 5375 Naiman Parkway. Cleveland. Ohio.
44139
Matcner Mlg Co Inc.. P 0. Boi 789. Grundy. Vo. 24614
Motal Carbides Corp. 6001 Southern Bl.d Youngsloan. Ohio,
44512
Moloi Corp, PO Boi 10156. Helsinki 10. Finland
Molrilapa Inc. 33 8rodl 14858. St. Louis. Mo, 63178
Molded Dimensions Inc, 701 Sunset Rd, Pi. Washington. Wise,
53074
Monitor Mlg Co, 200 N. Island Ave. Batavia, III, 60510
Monitrol Mlg Co PO Boi 3296. Tyler. Teias. 75701
Monogram Industries. Inc, 4030 Freeman Blvd.. Redondo Beach.
Cal, 90278
Monsanto Co, 800 N. Lindbergh Blvd.. SI. Louis. Mo. 63166
Montreal Engineering Co. Ltd, PO. Box 777. Puce Bonoventure.
Montreal. Canada
Moore Co, The. P. 0. Boi 753. Charleston, W. Va, 25323
Moore Industrial Battery Co, 4312-20 Spnng Grove Ave, Gncin
nati. Ohio. 45223
Moore. Samuel & Co. Synllei D». Mantua. Ohio. 44255
MorganUmn Machine 4 Hydraulics. Inc, Ou Nail. Mine Service Co,
PO Boi 986. Morgantown. W. Vo, 26505
Morns Pumps. Inc, 3) E. Genesee Si. BaMnnsnlle. N. Y, 13027
Kone Bros Machinery Co 1290 Ha'lan SI, Denver. Colo. 80214
Morse Cnoin. Div ol Borg Womer Corp. So Aurora St, Ithoco, N Y ,
14850
Morse Controls Div. Rrjckoall Intl. 21 Clinton SI. Hudson Ohio
44236
Morton Son Co. 110 N Wockfr Dr, Chicago. Ill. 60606
Kosctech Manulacturmg Co. 1115 Arlington Ave . Pittsburgh, Po,
Motorola Cornmumcttions & Electronics, 1301 E Algonquin Rd,
Schaumbura, 111.60196
Mod. B. H. & Sons. Inc, 814-846 6th Ave, Huntmgton. W. Va,
25701
Multi Amp Corp. 4271 Broom Way. Dallas. Tei .75237
MyeryWholey Co. P 0 Boi 4265. Knoiville. Tenn, 37921
N.L. Industries, Bearings Div, 5461 Southwyck Blvd Toledo Ohio.
43614
Nachod & U.S. Signal Co. 4777 Louisville Ave.. Louisville, Ky.,
40221
Nagle Pumps. Inc. 1249 Center Ave . Chicago Heights. Ill. 60411
O Nalco Chemical Co, 2901 ButterMrJ Rd. Oak Brook, in, 60521
O Nash Engineering Co, 310 Wilson Ave. Nomalk. Conn, 06856
National Air Vibrator Co, 6880 WynnwxM Lane. Houston, Teias.
77008
ONaiional Car Rental Systems Inc. Mudcal Div. PO Boi 16247. St.
Louis Park. Minn. 55416
0 National Castings Div, Midland-Ross Corp, 2570 Woodhill Rd,
Cleveland. Ohio. 44104
Ndlronal Electric Cote. Drv National Electric Control Co, 2931
Higgins Rd, Elk Grove Village. Ill, 60007
National Etectnc Coil D». ol McGran-Cdison Co, 941 Outturn
Lane. Suite 301. Columbus. Ohio. 43221
National Engineering Co, 20 North Wacher Dr, Suite 2060,
Chicago. Ill, 60606
National Environmental Insl Inc.. P 0. Bo> 590. Pilgrim Station.
Warack, R I, 02888
National Filter Media Coip, 1717 Diimll Aw, Hamdai Com,
06514
National Foam Syslom Inc, 150 Gordon Dr. Lonnlki. Pa., 19353
ONolronal Iron Co, 50 An. W & Rcmtoy Si, Dukim. Minn .5)807
ONalionai Mirw Sornto Co. 3000 Kurgan CMj PiRsturtfi. Pa.
15219
O National Standard Co, Perl tanals 0», 166 Dundatf Si, Ccrttfflv
dole. Po. 18407
National Supply Co, Oiv olArmco Sled Corp, I455W Loop South.
Houston. Ten, 77027
Nayloi Pico Co, 1265 E. 92 St, Cheap, III. 60619
Nefl & Fry. Inc. I SO S Mom Si. Carreten. Ohn. 45311
Nestle Co. Daar Pert Spring Waw. 100 Bloomingdct! Rd, White
Plains.. N Y. 1060S
New York Btowr Co, 3155 S SherMs Ave, Chicago. III. 60616
MF[ International Lid. 413 W. University Dr, Mngton HaQMs. IFJ,
60004
Niles Eipanded Mauls, 403 No. Pteosoil Ave, Nim. Otto. 44446
O Nolan Co, Ite Bo« 201. 8o«fsttm. Ohn 44695
Non.Fiurd Oil Corp, 298 Dalancy St, Nraarh. N. J, 07105
Norns Industries. Fire & Safety Equipment Dtv.. P.O Boi 2750. U.S.
"Highway No l.Nsaonx NJ. 07114
North Amsnmn Gd« Co. Rte. 7 Eosl. P.O. Boi 3158. l&rrcntoan,
W Vo, 26505
North American HydrouCa. Inc.. P.O Boi l5431.BotonRoicj8.Lfl,
70895
North American Mfn Co, 4455 E.7lsl Si. Ctevdcnd, Oho, 44105
North Amoncon 0£K. 222 S Rnerute Plan. Cnxcjo, a. 60606
North Stale PyroohyCitfl Co, Inc. P 0 Boi 724 7. Greautore. N. C,
27407
Northvast Engrg. Co:, 201 West Walnut. Grcan Bay. Wi, 54305
Norton Co, 1 N» Bond SI, vVorcester, Uass. 01606
Numonia Corp. 418 Piorce St, Sle 3. Lcntdcb. Pa. 19446
NUS Corp. Hobmwn A Rotmson Drv.. 1517 Cterteston fetinnd
Plau, Chartaston. W. Va, 25301
0 t K Orenstew & Kapp«l AG. Karl Funtu-Str. 30. 0-4600 Cam
mund, Germany
Ocenco. Inc, Magna-ftum Div. PO. Boi 8. 101 Industrie! Pb.
Blairsville. Pa, 15717
O O'Donnell t Associates. Inc.. 5180 Centre Ave, Pittsburgh. Pa,
15232
Ohio Brass Co, 380 N .Mam Si. Manslidd. Ohco. 44902
Ohio Carbon Co, 12508 fterea Rd. Ctevdsnd. Ohio, 44111
Ohn Rrrar Co. Tin, P.O. Boa 1460. Cncmncti. Oto. 45201
Ohio Tromfmmcr Corp, P.O Boi 191. 1776 Constituten A«..
Louavffla, Ohio, 44641
Ohmart Corp, 4241 ABatdorl Dr. P. 0. Boi 9026. Cmomoti. Oto.
45209
Oil Center Research, 320 Haymann Boumerd, UlayotU Lo,
70501
Okonile Co. P 0 Boi 340. Ramsey, N J. 07446
Old Republic Insurance Co, 414 W. Pittsburgh St, Greenjourrj, Po.,
15601
Onoi. Inc, 240 Hamilton An, Palo Alto. Ca, 94301
ORBA Corp. P.O Bo< 571. Superior, Wise. 54880
Ore Reclamation Co, 301 N Connai Ave, Ptchw. Qua., 74360
Ortner Freight Car Co. 2652 Ere Ave, Cmcmnab. Ohio. 15208
Oshkosh Truck Corp, PO Boi 2566, Othkosh,, Wrs, 54901
Osmose Wood Presermn, Co ol Amao Inc. 980 EDicon SI, But-
U). N Y, 14209
OutotumpuOy.TcthnxdE.psirtD.v.P.O.B 27.02101 Espoo 10,
Finland
O Over loos Co. he. .2787 S Teron. Engtmood. Colo. BOI 10
Owatonna Tool Co, 791 Eisenhower Drive, Owatormo, Minn,
55060
Owen BucM Co. The. 6001 Breakwater Ave, Cleveland.. Ohio.
44102
Owens-Coming Fitsrglas Corp, Fiberglass Tower, Toledo. Ohio,
~ 43659
Q Owoni Mlg. Inc. P 0. Boi 1490. Bristol, Va, 24201
PIM Products. Oiv Scott & Fetter. 4799 W. 150 Si, Cbvdcnd.
Ohio. 44135
PPG Industries. Inc. Chanted Div, One Gateway Center. Pittsburgh.
Pa. 15222
Pace Transducer Co, On. of C.J Enusrpritav P.O. Boi 834, Tortono,
CA. 91356
Paceco.ADrv olFruchoulCorp.2350Ebratui8A«,Atonato.Cd,
94501
° Padle, t Vorubkn Ltd. Collywhite Lano. OronlKid, St»«ica SIB
6XT, England
Page Engrg. Co, Cteonng Pnt Offico. Oitccjo, in, 60638
O Pall Corp. 30 Sea Cliff Aw, Gten Covo., NY. 11 $42
O Palm Industrie, Boi 680. Utchtaa, Mm, 55355
Parker.Hannihn Corp, KOM Products Oiv, 30240 Laholntd. Kncb.
liffe. Ohio. 44092
Parker-Honnlin Corp. Pooor Units Div, 17325 Euclid Avo., Cbvo-
land.,0ha, 44112
Partter-Honrafin Corp, Tuta Fmmgs Drv, 17325 Euclid Avo, Ctwo-
iand.Oha.44112
720
-------
Partison Corp.. 5601 N.E. 14th Aye., Ft. Lauderdale. Fla.. 33334
Patent Scaffolding Co.. 2125 Center Aye.. Fort Lee, N.J.. 07024
Patterson-Kelley Co., Div. of Taylor Wharton Co. • Harsco Corp, 100
Burson St.. East Stroudsburg. Pa, 18301
Pattin Manufacturing Co.. Div. The Eastern Co.. P. 0. Bo> 659. Mari-
etta. Ohio. 45750
Paulsen Wire Rope Corp., 2111 Tehoupitoulas SI. New Orleans. La..
70130
Paurat GmbH, NordstraBe. 4223 Voerde 2, W. Germany
Peabody ABC. P.O. Boi 187. Warsaw. Ind. 46580
Peabody Barnes, 615 N. Mam St., Mansfield. Ohio, 44902
Peabody Galon Div. of Peabody Gallon Corp. P.O. Boi 607. Gallon,
Ohio. 44833
Peerless Conveyor 4 Mfg. Co.; Inc.. 3341 Harvester Rd.. Kansas
City. Kan. 66115
fertess Hardware Mfg. Co.. 210 Chestnut St., Columbia,. Pa..
17512
• Vmco Corp, Boi 1338. BluehekJ. W. Va, 24701
• ifem Machine Co, 106 Station St. Johnstown. Pa.. 15905
• Ifemsytvana Crusher Corp., P. 0. Boi 100 CA, Broomall. Pa..
19008
l>ennsytvama Electric Coil, Inc., 1301 Saw Mill Run Blvd.. Pittsburgh.
Pa.. 15226
• Itemral Co.. Drake Building, Oil City. Pa, 16301
l"ennw>. Div. Pemuoil Co.. 106 S. Mam St.. Butler. Pa, 16001
I >eraR) Engineering ltd, Brittam Dr.. Codnor Gate Ind Estate. Ripley.
Derbyshire OE5 3QB. England
I'erkm-Elmer Corp., Main Ave.. Norwalk.. Conn.. 06856
I'ersingere Inc.. P.O. Boi 1886. 520 EluabeUi St.. Charleston. W
Va.. 25327
Peterson Filters & Engineering Co.. P.O. Boi 606. Salt Lake City.
Utah. 84110
I'etrogen Inc. P.O. Boi 1592. Richmond. Cal, 94802
Ivjttibone Corp, 4710 W Div. St., Chicago. ».. 60651
IWtibone Corp.. Ptttibone New York Dn.. 1212 E Dominick St.,
Rome, NY., 13440
Itelps Dodge Industries. Inc., 300 Park Ave.. New York. N Y..
10022
• Itiiladelphia Gear Corp., 181 S. Gulpfi Rd.. King of Prussia. Pa.
19406
Ftiilippi.Hagenbuch Inc. Ltd.. 1815 North Knomlle. Peoria. III.
61603
Phillips Mine t Mill, Inc., P. 0 Boi 70. Bndgeville. Pa.. 15017
Phillips Products Co.. Inc.. Suite 120, Dallas. Tei., 75234
Fhoenii Products Co.. Inc.. 47)5 North 27th St., Milwaukee. Wis..
53209
Pitman Mfg.. Co.. Div. A.8. Chinee Co.. P.O. Boi 120. Grandvcw.
Mo., 64030
Pittsburgh Coming Corp.. 800 Presque Isle Dr. Pittsburgh, Pa..
15239
• Plastic Techniques, Inc. R.D. * 3, Boi 91. Clarks Summit. Pa..
18411
Plibrico Company, 1800 Kingsbury St.. Chicago,. III., 60614
• Plymouth Rubber Co, Inc., 51 Revere St.. Canton, Mass. 02021
• Pury-Hi, Inc.. 2710 American Way. Fort Wayne, Ind., 46809
• Pxttdnll, Div. of Smith International Inc.. 2201 Blake St.. Denver.
Colo, 80205
Pxtec, IK, Pioneer Div, 3200 Como Ave, S. E, Minneapolrs, Minn,
55414
Pxter. H.K. Co, Inc.. Porter Bldg, Pittsburgh. Pa, 15219
Pjrter. H K, Inc., 74 Foley SI, Somerville. Mass.. 02143
Pxto Pump, Inc, 19735 Ralston, Detroit Mich, 48203
Bat-Glover Div, ESB Inc, Boi 709. Conngton. KY, 41012
Power Transmission On, Dresser Industries, Inc, 400 W. Wilson
Bridge Rd, Worthington. Ohio. 43085
Pierser/Mineco Div, Preiser Scientific Inc, Jones & Oliver St.. St.
Albans, W. Va.. 25177
Pi estolite Battery Oiv. of Eltra Corp, 511 Hamilton St., Toledo. Ohio.
43694
Pi estolite Electrical Div. of Eltra Corp, P.O. Boi 931. Toledo. Oho,
43694
Pi estolite Wire Dw. of Eltra Corp, 3529 24th St.. Port Huron. Mich,
48060
Piinceton Aviation Corp, Telerboro Airport. Teterboro. N.J, 07608
Piocess Equipment. Stansteel Corp, 5001 S. Boyle Ave, Los An-
geles. Cal, 90058
Piocess Metals Co, P. 0. Boi 905, Elkhart., Ind, 46514
Programmed 4 Remote Systems, 899 W. Highway 96. St. Paul.
Minn, 55112
Piosser Industries. Div. of Purei Corp, P.O. Boi 3818, Anaheim.
Calif, 92803
Pru, Frank Co, Inc, P. 0. Boi 1484.1201 S. 1st St., Terre Haute.
Ind, 47808
Piflman Standard Div, Pullman Inc, 200 So. Michigan Ave,
Chicago. Ill, 60604
Pitman Torkelson Co. 10 West Broadway. St. Lake City. Utah.
84101
Pulmosw Safety Equp. Co, 30-48 Linden PI, Flushing. N. Y,
11354
Punemng Machinery. Div. of MikroPul Corp.. 102 Chatham Rd,
Summit. N J.07901
Pure Carbon Co, Inc.. 441 Hall Ave, St Marys. Pa. 15857
Pure Way Corp, 301 42nd Ave. E. Molme. Ill, 61244
• Py* National Co.. 1334 North Kostner. Chicago. III.. 60651
Pyjft-Boone, Inc, P.O. Boi 809. Taiewell, Va, 24651
• PyMt-Boone Machinery Corp.. Saltville. Va, 24370
Oust Electronics. 510 Worthmgton St, Oconomowoc. Wis, 53066
Quncy Compressor Dn, Cott Industries. 217 Maine Si, Qumcy. Ill.
62301
ROi, Mobile Communications Systems. Meadow Land. Pa, 15347
RM Controls. Hamesport Industrial Pk, Hainsport. N.J. 08036
RM Friction Materials Co„ Div. Raybestos Manhattan. Inc, 100 Oak-
new Or, Trumbull. Conn, 06611
RM Ml Products Co., On. Raybntos-Manhattan. Inc, P.O. Boi 157.
'^rk's Summit Pa.. 18411
Race International. Inc, 3350 Industrial Blvd., Bethel Park. Pa,
15102
Railweighl, Inc, 1821 Willow Rd. Northlield. III. 60093
Ramsey Engineering, Co, 1853 W. County Rd C, St Paul. Minn.
55113
Ransomes & Rapier Ltd, P.O. Bo> I. Waterside Works, Ipswich 1P2
8HL, England
Rapid Electric Co, Inc, Grays Bridge Rd, Brookheld, Conn, 06804
Raybestos-Manhattan Industrial Products Co, Garco St, No.
Charleston, S.C. 29406
Raychem Corp, 300 Constitution Or. Menlo Park. Calil, 94025
RayGo. Inc, 9401 • 85th Ave. No, Minneapolis. Minn, 55412
Red Comet. Inc, P. 0. Boi 272-Red Comet Bldg, Littleton. Colo,
80120
Red Vane Co, Inc, 500 Sell Ave, Carnegie. Pa, 15106
Red Wing Shoe Co, Inc, 419 Bush St, Red Wing., Minn, 55066
Redding Co, James A. 61S Washington Rd, Pittsburgh, Pa, 15228
Reed Manulacturing. P. 0 Boi 905, Walnut. Cal. 91789
Reed Tool Co, P.O. Boi 2119. Houston. Tei, 77001
Reggie Industries. 15 Spinning Wheel Rd, Ste. 332, Hmsdale. Ill,
10521
Remco Industries. P 0 Boi 584 Ptamlield. N J, 07061
Reiss Viking Corp, Div C. Reiss Coal Co, P 0 Boi 3336, 1300
Georgia Ave, Bristol. Tenn, 37620
• Reliance Electric Co. 24701 Euclid Ave. Cleveland. Ohio. 44117
Rema-Tech. 200 Pins Ave, Northvale. N J. 07647
Republic Steel Corp. P 0 So. 6778. 1441 Republic Bldg. Cleve-
land. Ohio. 44101
Research Cornell, Inc. P.O Boi 750. Bound Brook. N. J. 08805
• Research Energy of Ohio, 237 Charleston Si, Cadi;. Ohio. 43907
Resisto-Loy Co, 1251 Phillips Ave, S. W, Grand Rapids. Mich,
49507
Revere Corp ol America Sub ol Neptune Intl. Corp, North Colony
Rd, Wallmgford, Conn. 06492
Reiarc. Inc, Reiarc Place. West Akuandna. Ohio. 45381
• Reinord Inc, P.O Boi 2022, Milwaukee, Wis, 53201
• Reinord Inc, Process Machinery Div, Boi 383. Milwaukee. Wis.
53201
Reynolds Melals Co, P 0 Bo. 27003, Richmond. Va, 23261
Richmond Mlg Co. P.O Boi 188. Ashland. Ohio. 44805
Ridge Tool Co, Sub ol tmerson Electric Co, 400 Clark SI. Elyna.
Ohio. 44035
Ripco. Inc, 251 S 3rd St. Oilord. Pa, 19363
Rise Corp, 37 Midland Ave, Elmwood Park. N.J, 07407
Rish Equipment Co InU. P.O Boi 429, SI. Albans. W Va, 25177
Rish Equipment Co, Material Handling Systems Div, 2508 West
Main SI, Silem. Va. 24153
Riverside Polymer Corp, P.O. Boi 313. Palerson. N J. 07 524
Robtnns Co, 650 S Orcas Si, Seattle,. Wash, 98108
Robbms Dn, Joy Mlg. Co, 300 Fleming Rd. (P.O. Boi 6505). Bir-
mingham. Ala, 35217
Robbtns & Myers. Inc. 1345 Lagonda Ave, Springfield. Ohio
45501
Roberts I Schaeler Co, 120 S Riverside Plaza, Chicago. Ill, 60606
Robcon Corp, 100 Sagamore Hill Rd, Plum Ind. Park, Pittsburgh.
Pa, 15239
Robinson Industries, Inc. P.O. Boi 100, Zelienople. Pa, 16063
Rochester Corp, P. 0 Boi 312, Culpeper. Va. 22701
Rock Industries Machinery Corp, 4603 W. Mitchell. Milwaukee
Wise, 53214
Rock Tools, Inc, P.O Boi 17303. Salt Lake City. Utah. 84117
Rockwell International Flow Control Div, 400 N Leiington Ave,
Pittsburgh. Pa, 15208
Rockwell International, Power Tool Div, 400 N. Leiington Ave, Pitts-
burgh/Pa, 15208
Rockwell-Standard Div, Rockwell International Corp, P. 0. Boi 641.
Troy. Mich 48084
Rohm and Haas Co, Independence Mall West. Philadelphia, Pa.
19105
Roller Corp. P.O. Boi 12606. Pittsburgh. Pa, 15241
Rollway Bearing Co, P 0. 801 1397. Syracuse, NY. 13201
Rose Manufacturing Co, 2775 S. Valtejo. Englewood. Colo. 80110
Rost. H. & Co, Balatroswerke. P.O Boi 1168. D-21 Hamburg 90.
W Germany
Round. David & Son. Inc, P. 0 Boi 39156. Cleveland. Ohio. 44139
Rubber Engineering & Mfg. Co.. 3459 S. 700 West. Salt Lake City.
Utah. 84107
Rust Engineering Co, A Sub. of Wheelabrator-Frye Inc P.O. Boi
101. 1130 South 22nd SI, Birmingham. Ala, 35201
Rust-Oleum Corp, 2301 Oaklon St, E«anston. III. 60204
Ruttmann Companies, 425 W. Walker St, P. 0. Boi 120, Upper
Sandusky. Ohio, 43351
Ryerson. Joseph T, & Son. Inc, P. 0. Boi 8000A. Chicago. Ill,
60680
4>S 1 S Machinery Sales. Inc. Route 1, Cedar Bluff. Va. 24609
SI Regis Paper Co. 150 E 42nd St, New York. N Y . 10017
SKF Industries. Inc. 1100 First Ave, King ol Prussia. Pa.. 19406
Sala International. S 733 00 Sala, Sweden
Sala Machine Works lid. 3136 Mavis SI, Cooksville. Oni. Canada
t) Salem Tool Co, The. 767 S Ellsworth Ave. Salem. Ohio. 44460
Samson Supply & Mlg Inc. P.O Boi 462. Waterloo. Iowa. 50704
Sanderson Cydone Drill Co, 1250 E Chestnut St, OrmUe, Ohio.
44667
Sanlord-Day/Marmon Transmotive. Div ol the Marmon Group. Inc,
P.O. Boi 1511. Gov John Sevier Hwy Knoiville. Tenn, 37901
Sangamo Electric Co. 1301 N Illh St.. Springfield. III. 62708
Sauerman Bros, Inc, 620 S 28th Ave. Bellwood. Ill, 60104
Savage. W J Co. 912 Clmch Ave. S W. Knoiville. Tenn, 37901
Scandura. Inc P. 0 Bo> 949, 1801 North Tryon Si. Charlotte,
N C.28201
• Scfcaeler Brush Mlg Co. II7 W Walker SI, Milwaukee. Wis.
53204
Schalfer Poidomeler i Machine Co. 2828 Smallman St, Pitts-
burgh. Pa. 152.'.'
Schauenburg Fleiadui Corp. 12 A Buncher Ind. Dist. Leetsdale.
Pittsburgh. Pa. 150S6
• Schramm Inc, 901 E Virginia Ave. West Chester. Pa, 19380
• Schroeder Bros. Corp. Nichol Ave. Boi 72, McKees Rocks. Pa,
15136
Scott Aviation A Oiv. ol A to Inc, 225 Erie Si, Lancaster. N. Y,
14086
721
Scoll Midland Oiv. A 1-0 Inc. 11099 Broadway. Alden.'N Y
14004
Screen Equipment Co. Div Hobam inc.. 40 Anderson Rd Buffalo
N Y. 14225
Seiberlmg Tire 4 Rubber Co. 34b I5ih Si NW. PO Boi 189,
Barberton. Ohio. 44203
Semmole Products Co. Inc , Bo. 123. Glendora. N J. 08029
Seneca Helicopters Inc, PO Boi 882. Oil Cil«. Pa. 16301
Serpentu Conveyor Corp. 1550 S Pearl St. Denver. Colo. 80210
Servus Rubber Co, 1136 Second St. Rock island. Ill. 61201
Seton Name Plate Corp, 1654 Boulevard. New Haven. Conn.
06505
•Sevcon. Oiv of Tech/Ops. 40* South Ave. Burlington. Mass,
01803
Shannon Optical Co. Inc. 3825 Willow Ave. Pittsburgh, Pa. 15234
fShaw-Almei industries Ltd P 0 Boi 430. Parry Sound. Ont.
Canada
Shell Chemical Co. Chemical Sales. P 0 Boi 2463. Houston. Tei.
77001
Shell Oil Co, One Shell Pla». Houston, Tens 77002
Shingle. L.H. Co. 500'Gravers Rd. Plymouth Meeting, Pa. 19462
Shirley Machine Co. On. Tasa Corp. Suite 2701. Gateway Towers.
Pittsburgh. Pa. 15222
Shwayder Co. 2335 E Lincoln. Birmingham. Mich. 48008
Siemens Corp. 186 Wood Ave. South. Isefcn. N J. 08830
Sigmalorm Corp. 2401 Walsh Ave. Santa Clara. Cal. 95050
Sn Onto Industrial. Div of Smith Intl Inc. . Drawer 3135. M«J-
land. Tei. 79701
• Simplicity Engineering. 212 S Oak Si. Durand Mich. 48429
Seui Steam Cleaner Corp. Beresford. S 0. 57004
Sly. W W. Mfg. Co, PO Boi 5939. Cleveland. Ohio, 44101
Smico Corp. 500 N. Mac Arthur Bird. Oklahoma City.. Okla.
73127
Smit. J K. & Sons. Inc. 571 Central Ave. Murray Hill. N J. 07974
Smith. A 0. Inland Inc Reinforced Plastics On. 2 700 West 65th St.
Little Rock. Ark. 72209
Smith international Inc.. 4667 Lecarthur Blvd. Newport Beach.
Calif. 92660
Smith Tool. 17871 Von Karman Ave. Irvine. Cal. 92714
Snap-On Tools Corp, 8132 28tn Ave, Kenosha. Wis. 53140
Soiltesl. Inc, 2205 Lee St. Evanston. Ill, 60202
Solids Flow Control Corp, 37'Midland Ave, Elmwood Park. N. J.
07407
Somerset Welding & Steel Inc, 733 S Center Ave, Somerset, Pa.
15501
Sonic Development Corp, 3 Industrial Ave. Upper Saddle River. N.J.
07458
Sortei Co of North America. Inc. PO Boi 160. Lowell. Mich.
49331
Southern Tire Co, 1414 Broadway. Sheffield. Ala.
Spang t Co, P 0 Boi 751. Butler. Pa. 16001
Speakman Co, P. 0 Boi 191. Wilmington. Del. 19899
Specialty Services. Inc.. 6152 Steeplechase Dr.. S W. Salem. Va.
24153
Spectrum Infrared Inc, 246 E 131s! St, Cleveland, Ohio. 44108
Sperry Vickers On. Sperry Rand Corp. P 0. Boi 302, Troy. Mich.'.
48084
Sperry Vickert. Tulsa On, P 0. Boi G, Tulsa. Okla, 74115
Sprague 4 Kenwood. Inc. 221 W. Olne St, Scranlon. Pa, 18501
Spraying Systems Co, North Ave. al Sen/rule Rd, Wheaton. »,
60546
Sprengnether. W. f. Instrument Co. Inc. 4576 Swan Ave, Si Lous.
Mo.63110
Sprout-WaMron. Hoppers Co, Inc. Muncy. Pa. 17756
Square 0 Co, Executive Plan. Park Ridge. W. 60068
Stamler. W R. Corp. The. 600 Tngg St. Mrflersburg.. Ky. 40348
Stanadyne/Hwttord ON, Boi 14457Hartford. Com. 06102
Stance Mlg & Sales Inc. 800 Spruce Lake Or. Harbor City. Cwl.
90711)
Standard Metal Mfg Co, P 0 Boi 57. Maknta, Ohio. 43535
Stauffer Chemical Co, Specialty Chemical Dn. Westport. Com,
06880
Steams Magnetics Inc. Oiv of Magnetics kill, 6001 So General
Ave, Cudahy. Wis. 53110
Stearns-Roger Inc. 700 So Ash. PO. Boi 5888. Denver. Colo,
80217
Stedman Fdy. i Mach. Co, P.O. Boi 209. Aurora Ind. 47001
Steel Heddle Mfg. Co, Industrial Dn. 1801 Rutherford Si (P.O. Boi
1867), Greenville. S.C, 29602
Steelpiank Corp, 415 Goddard Rd. Wyandolte. Mich. 48192
Stellite Oiv. Cabot Corp, Kokomo. Ind. 46901
• Slephens-Adamson. Ridgcway Ave. Aurora. Ill, 60507
Sterling Custom Built Trucks. 5000 Mackey. Mernam. Kan, 66203
Sterling Power Systems. Inc, A Sub ol The Lionel Corp, 16752
Armstrong Ave, Irvine. Calif. 92714
Stevens. Inc.. C W, P. 0. Boi 619, Kennett Sq.. Pa. 19348
Slonhard. Inc, Park Ave. & Rte. 73. Maple Shade. N. J. 08052
Stood* Co.Boi 1901 CA. Industry, Cal. 91749
Stoody Co. WRAP Div, 11804 Wakeman Si, Whittier. Cal, 90607
Straighllme Filters Inc, P.O Boi 1911, Wilmington. Del. 19899
Stratohei. Inc, P 0 Boi 10398. Ft. Worth. Teias, 761)4
Straub Mlg Co, 8383 Baldwin St, Oakland. Cal. 94621
Streeler Amet. Div ol Mangood Corp, Slusser 4 Wicks, Grayslake.
Hi 60030
Stroreiport. pro, Vaclavske Nam 56. Prag 1. Ciechoslovakia
SJrombergCarlson Corp. PO. Boi 7266. Cnartottesmie. VI,
22906
Siurtevanl Mill Co, 22 Sturtevant St, Dorchester. Boston, Mass.
02122
Sullair Corp, 514 Washington Rd, Pittsburgh. Pa. 15228
Sun Oil Co, 1608 Walnut Si, Philadelphia. Pa. 19103
Sundsirand Flud Handling, Div. Sundstrand Corp. 2480 W. 708i
Ave. Denver. Coto. 80221
Super Products Corp, P 0 Boi 27225. Milwaukee. Wise. 53227
Swan Hose Div, PO. Boi 509, Worthmgton. Otic. 43085
SWECO. Inc. 6033 E Bandini Bnd. P.O Boi 4151. los Angeles.
Calil.90051
> TBA Industrial Products Ltd. P.O Boi 77. Wigan WN2 4XQ. Lanca-
shire, England
TJfllnc. 19940mgersollOr, Rocky River. Oho 44116
T i T Machine Co, Inc.. Rte 8. Boi 343. Fairmont. W. Va, 26554
-------
Tiber Pump Co.. Inc.. P. 0. Bo. 1071. Elkhart.. Ind.. 46514
Tampella-Tamrock. 33310 Tampere 31. Finland
Taylor Instrument Process Control Oiv. Sybron Corp.. 95 Ames St.,
Rochester, N.Y., 14601
Taiewell Industries. P.O. Boi 431. Taiewell. Va. 24651
Teledyne McKay, BSD Grantley Rd, York, Pa., 17405
Tetodyne Western Wire & Cable, 2425 E. 30th Si. Los Angeles.
Calif, 90058
Teledyne Wisconsin Motor. 1910 S. 53rd St.. Milwaukee, Wis..
53219
Telsmith Din.. Barber-Greene Co, 532 E. Capitol Dr.. Milwaukee.
Wis.. 53212
Templeton, Kenly & Co.. 2525 Gardner Rd.. Broadview, III.. 60153
•Terei 0», CMC. Hudson. Ohio. 44236
Terrell Machine Co., Industrial Products Oiv. P. 0 Bo. 928. Char-
lotte. N.C., 28201
Teuxo Inc.. 2100 Hunters Pant Ave, long Island City, N. Y,
IIIOI
Teias Nuclear. 9101 Research Rd (PO Boi 9267). Austin. Teias.
78757
Thayer Scale Hyer Industries. Rt 139. Pembroke. Mass .02359
Thermei Metallurgical Inc., Rdgeway Blvd.. Lakehurst. N. J, 08733
Thomas Foundries Inc., P.O. Boi 96. Birmingham, Ala. 35201
Thor Power Tool Co, 175 N State St.. Aurora. Ill. 60b07
Throwaway Bit Corp., 624 N. East Everett. Portland. Ore.. 97232
• Thurman Scale Co. Oiv. Thurman Mfg. Co.. 1939 Refugee Rd..
Columbus. Ohio. 43215
Tiger Equipment & Services. Ltd /O & K Mining Equipment. 222 S.
Riverside Plaza. Chicago. Ill. 60606
Timken Co.. 1835 Oueber Ave. S W. Canton. Ohio. 44706
Todd Ent. Inc.. 530 Wellington Ave, Cranston. R. I.. 02910
Tol-0-Mauc. 246 IOth Ave.. So.. Minneapolis. Minn., 55415
Tool Steel Gear & Pinion Co.. 211 Town*ip Ave., Cincinnati. Ohio.
45216
Tori! Oiv. Donaldson Co. Inc.. P.O. Boi 3217. St Paul. Minn, 55165
Tornngton Co, The Bearings Oiv, 3702 W. Sample Si, South Bend,
Ind, 46634
TOTCO Div -Baker Oil Tools. Inc.. 506 Paula Ave, Glendale. Calit.
91201
Toyo Tire (USA) Corp., 3136 E. Victoria St, Compton. Cal. 90221
Trabon Lubricating Systems. Oiv ol Houdaille Industries. Inc..
2881S Aurora Rd, Solon,. One, 44139
Tracy. Bertram P Co, 919 Fulton St, Pittsburgh. Pa, 15233
Tread Corp. Bo> 5497. Roanoke. Va, 24012
Treadwell Corp, 1700 Broadway. New rork, NY. 10019
• Trelkiborg Rubber Co, Inc.. 30700 Solon Ind. Pk». Solon. OH.
44139
Tnangle/PWC. Inc.. A Sub. ot Triangle Industries. Inc.. Bo> 711.
Triangle & Jersey Aves, New Brunswick. N. J, 08903
Trco Mlg. Corp., 2948 N. 5th St, Milwaukee, Wis, 53212
Tricon Metals & Services, me, P.O. Boi 6634. Birmingham, Ala,
35210
Troian Oiv IMC Chemical Group. Inc. 17 N, 7lh St.. Allentown. Pa,
18105
Trowelon. Inc, 973 Haven Dr, P.O. Bo< 3126. Green flay. Wis,
54303
TRW Mission Mlg, Co, Div ol TRW Inc, H,0 Bo« 40402, Houston,
Teias. 77040
• Tube-lok Products Div. ol Portland Wire & Iron, 4644 S 1. 17lh
Ave, Portland. Ore, 97202
Tube Turns Div, Chemelron Piping Systems. 2900 W Broadway.
Louisville. Ky., 40201
TWECO Products, Inc, P. 0 Boi 666. Wichita. Kan. 67201
Twin Disc. Inc. 1328 Racine Si, Racine. Wis .53403
Twisto-Wire Fire Systems, Inc, 302 E Hunlington Dr, Arcadia. Calif,
91006
u
Underground Mining Machinery Lid. P 0 Box 19. Ayclilte Industrial
Estate, Oarlmgton. Co Durham Dl 5 60S, England
Umfloc Limited. 11/16 Adelaide Si, Swansea. U.K.
Unilok Belting Co, Div. ol Georgia Duck and Cordage Mill, Scottdale,
Ga, 30079
Union Carbide Corp, 270 Park Ave, New York, N Y, 10017
• Union Oil Co ol California. 200 E. Golf Rd, Palatine. Ill, 60067
Union Forge, Inc. Stop St. Noolestown. Pa, 15070
Unique Products Co. 12867 Mac Neil St, Sylmar. Calif 91342
Umroyal, Inc, 1230 Ave ol Americas. New York. N Y. 10020
Unit Crane & Shovel Corp .1915 South Moorland Rd, New Berlin.
Wis, 53151
United McGill Corp, 2400 Fauwood Ave, Columbus. Ohio. 43216
U.S. Electrical Motors Oiv Emerson Electric Co, 125 Old Gate Lane.
Milloid, Conn. 06460
U S. Gypsum Co. 101 S Wacker Dr. Chicago. Ill, 60606
U. S Polymeric. Sub ol Armco Steel Corp, 700 E. Dyer Rd, Santa
Ana. Cal, 92707
United Slates Steel Corp, 600 Grant St - Rm 2106, Pittsburgh. Pa,
15230
United Tire t Rubber Co Ltd, 275 Bellield Rd, Reidale, On!
Canada. M9W5C6
Unt Too) Attachments. Inc, 1607 Woodland Ave, Columbus. Ohio.
43219
Universal Atlas Cement Co, 600 Grant St. 12th Fl. Pittsburgh,. Pa.
15230
• Universal Industries. P 0 Boi 98. 245 S. Washington. Hudson.
Krna. 50643
Universal Road Machinery Co, 27 Emerick Si, Kingston. NY,
12401
Universal Vibrating Screen Co, P 0. Boi 1097. 1745DeaneBlvd.
Racine. Wis, 53405
VME-Nitro Consult, Inc , 1732 Central St., E»anston, III, 60201
Valley Steel Products Co. P.O Boi 503. Si Louis. Mo. 63166
Van Gorp Mfg Inc. Bo. 123. Pella, Iowa. 50219
Varel Mlg Co. Inc, 9230 Demon Dr, P. 0 Boi 20156, Dallas.
Teias. 75220
Vanan Associates. 611 Hansen Way. Palo Alto. Calil .94303
Vehicle Constructors Div. Marion Power Shovel Co. 7336 Air Freight
Lane. Dallas. Tei. 75235
Vibco Inc . P 0 Boi 8 Slilson Rd . Wyoming. RI 02898
Vibranelics. me. 2 714 Crirtenden Dr. Louisville. Ky. 40209
• Vibra-Screw Inc . 755 Union 8l»d Tolowa. N J. 07512
•) Victauhc Co ol America. 3100 J Hamilton Blvd.. So Plamtield. N J.
07080
Victor Products (Wallsend) Ltd. P 0 Boi Wallsend. Tyne and Wear
NC28 6PP. England
Viking Oil A Machinery Co. Rt 8. Orebank Rd, Kingston. Tenn.
37664
Vortei Air Corp. PO Boi 928. Beckley. W va. 25801
• VR/Wesson a On/ ol Fanned. 800 Market St. Waukegan. Ill.
60085
Vulcan Materials Co. Southeast Oiv. P 0 Boi 7324-A. Birmingham.
Ala. 35223
W
• WABCO Construction and Mining Equipment Group, an American-
Standard Co. 2300 NE Adams St. Peoria. 111.61639
WA8CO Fluid Power Div. an American Standard Cu. 1953 Mercer
Rd Leimgton. Ky, 40505
WABCO Union Switch & Signal Div. Westmghouse Air Brake Co, an
American-Standard Co, Pittsburgh. Pa, 15218
Wacns. E H. Co. 100 Shepard Si. Wheeling. Ill. 60090
Wagner Mining Equip. P. 0 Boi 20307, Portland, Ore. 97220
Waiai Industries' Ltd, 350 Sparks St. Ste 1105. Ottawa. Onl,
Canada. KIG 3C8
Walco Industries Inc, N W Cor. Race S Camac Sis. Philadelphia
Pa.19107
• Waldon me. Fairview. Okla, 73737
Walker Parkersburg Teitron. 620 Depot Si. Parkersburg, W Va,
26101
Wai! Colmonoy. 19345 John R St. Detroit. Mich. 48203
Wallacetown Engineering Co. Ltd, Heathlield Rd. Ayr KA89 SR Eng-
land
Walter Nold Co, 24 Birch Rd. Natick. Mass. 01760
Ward Hydrauks Oiv, ATO Corp. 11980 Walden Ave Alden N Y.
14004
Warman International, Inc. 2701 S Sloughlon Rd, Madison Wis.
53716
About the Buying Directory. . .
This 1976 edition of the Coal Age Buying
Directory remains the most complete di-
rectory of equipment, supplies, and ser-
vices available to the coal mining industry.
For several years, the entire directory has
been stored in a computer data bank. Early
each year, a computerized questionnaire is
printed for each listed manufacturer, show-
ing the categories under which his prod-
ucts appeared in the preceding edition of
the Buying Directory.
Each manufacturer is asked to revise the
listing where necessary, adding any new
products or services available to the coal
mining industry.
The information supplied by manufac-
turers is then used to update the comput-
erized listing and is stored in the data
bank.
722
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Warn Industries. 19450 68th Ave. So.., Kent. Wash. 98031
Warner 1 Swasey. Construction Equipment. Solon. Ohio. 44139
Warren Rupp Co.. The. 800 N, Main. P.O. Boi 1568. Mansfield, Ohio.
44<01
Watt Ciir t Wheel Co.. Bo> 71. Barnesville. Ohio. 43713
Waukesha Engine Div.. 1000 St. Paul Ave.. Waukesha. Wis .53186
• Weatherheao Co.. The. 300 E 131H St.. Cleveland. Ohio. 44108
Webb. .ervis B, Co. 9000 Alpine A«e. Detroit. Mich, 48204
Webste' Mlg Co, W Hall St. TiHin. Ohio. 44883
• Wedge Wire Corp. P. 0. Boi 157. Wellington. Ohio. 44090
Weir. Piul Co. Inc. 20 N. Wicker Or, Chicago. Ill. 60606
Wellmai. S K.. Corp, The. 200 Egbert Rd.. Bedford. Ohio. 44146
Wells Cirgo Inc.. P.O. Boi 7128 C*. Waco. Ten, 76710
Welsh (in. ol Textron. 2000 Plamlield Pike, Cranston, R1.02920
WEMCtl Div.. Envirottch Corp.. P 0. Boi 15619. Sacramento. Calil.
95lil3
Wen-Den Crxp, P.O. Bon 12094. Roanoke. Va.. 24022
Wescot: Steel Inc. 1020 Washington Ave.. Croydon. Pa.. 19020
WESM/R Level Monitor Div.. 905 Dexter Ave. N.. Boi CI9074.
Seattle. Wash.. 98109
West Virginia Armature Co.. P. 0. Boi 1100, 8luelield. W. Va.
24V01
West Virginia Bell Sales & Repairs Inc., P. 0. Box 32. Mount Hope.
W. Va, 25880
Westeni Precipitation Div.. Joy Mlg Co.. P. 0 Box 2744. Terminal
Annex. Los Angeles. Calil.. 90051
WesHalia Lunen. D 4670 Lunen. P.O. Box. Germany
Westinithouse Electric Corp.. Westinghouse Bldg.. Gateway Center.
Pittsburgh, Pa. 15222
Westlalie Plastics Co. Lenni Rd.. Lenni. Pa.. 19052
Wheelatxator-Frye Inc.. Air Pollution Control Div, 600 Grant Si,
Pittsburgh. Pa, 15219
Wheelabrator-Frye, Inc, Materials Cleaning Systems, 14765 Byrkil
St, Mishawaka. Ind. 46544
White Engines. Inc, 101 • 11th Si, St. Canion, Ohio, 44707
White Motor Corp -Truck Group, 35129 Curtis Blvd. Eastlake. Ohio.
44094
While Superior Div, White Motor Corp, 1401 Sheridan Ave Spring-
lield. Ohio. 45505
Whiting Corp. 15 700 Lalhrop. Harvey. Ill. 604 26
Whitmore Mlg Co. III*. P 0 Box 488. Cleveland. Ohio. 44127
Whmaker Corp. 10880 Wilshire Blvd. Los Angeles. Calil. 90024
Wichita Clutch Co. Inc. 307 Barwisa SI. (P 0 Box 1550). Wichita
Falls. Texas. 76307
• Wifgand. Edwin I , Div . Imerson Elec Co , 7867 Thomas Blvd ,
Pittsburgh. Pa. 15208
Wiggins Connectors Div Delaval Turbine Inc, 5000 Inggs Si. Us
Angeles. Calil, 90022
Wild Heertxugg Insts Inc. 465 Smith St, Farmmgdale, N Y.
11735
• Willley. A R, t Sons. P. 0 Box 2330. Denver. Colo, 80201
Williams. J. H. Div ol TRW Inc, 400 Vulcan St. Bullato. N. V, 1420 7
Williams Patent Crusher & Pulv Co, 810 Montgomery SI, Si. Lous
Mo.63102
Willis 4 Paul Corp. The, 125 135 Main Si, Netcong. N. J.. 07857
WilsonEngineenngCo.2101 Pleasant Valley Rd, Fairmont. W Va.
26554
Willson Products Div. ESB, Inc. P. 0. Box 622. Reading. Pa, 19603
Wilmot Engineering Co, Berwick SI, White Haven. Pa, 18661
• Wilson. R. M Co. Box 6274. Wheeling. W Va. 26003
Wing Co, The. Div ol Aero-flow Dynamics. Inc. 2300 N Stiles Si.
Linden. N.j, 07036
Wmslow Scale Co, P.O. Box 1523. Terre Haute Ind, 47808
Wire Cloth Enterprises. Inc. RIDC industrial Park. Pittsburgh. Pa.
15238
Wire Rope Corp ol America, Box 288. Si Joseph. Mo, 64502
Wooo s. T B, Sons Co. 440 N. Filth Ave Chamoasburg Pa
17201
Workman Developments. Inc 1741 Woodvale Rd. Charleston. W
Va.25314
tworthington Pump Inc, 270 Sheffield Si. Mountainside. N J.
07092
Vardney Elect'K Corp. 82 Mechanic St. Pawcatuck Conn, 02691
Yaun-Williams Bucket Co, 10100 Brecksvdle Rd. Brecksvilte. Ohio.
44141
•Young Corp. Bo. 3522. Seattt-. Wash, 98124
Youngstown Sneel & Tube Co. The. Post Once Bo. 900. Youngs-
town. Ohio, 44501
Zem Drilling Co, 324 Eighth SI. Morgantown. W Va, 26505
723
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THIS PAGE INTENTIONALLY LEFT BLANK
724
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APPENDIX IX
English - Metric Conversion Charts
725
-------
CONVERSION FACTORS FOR BRITISH AND METRIC UNITS
To convert from
Op
r
£ .!_
J- I-.
2
ft.
3
ft.
ft./min. (fpm)
3
fts /mine
in.
2
in.
oz.
2
ozc/yd.
grains
2
grains/f to
3
grains/ft .
Ib. force
lb./ft.2
in. H O/ft./min.
BtU
To
°r
C
meters
2
meters
3
meters
centimeters/sec <=
3
centimeters /sec0
centimeters
2
centimeters
grains
2
grams meter
grams
2
grams meter
3
grams /meter
dynes
2
grams/centimeter
cnu H o/cm/seco
.. .
calories
Multiply by
— 1 O TT_ 1 O ^
— ( F-J^J
0.305
000929
0,0283
0.508
471.9
2.54
6,45
28034
33.89
Or\c. /I "7
o064 /
2O OQ
. <£OO
5
4o44 x 10
0,488
5.00
-> c o
/J^
To
centimeters
2
centimeters
3
centimeters
meters/sec o
3
meters /hr.
meters
2
meters
grains
2
grams/centimeter
newtons
grams/meter
2
Newtons/meter /cm/sec.
Multiply
30.5
92900
28,300.0
5o08
1.70
2.54
6.45
438.0
3.39
0.44
4,880.0
490.0
by
-3
x 10
-2
x 10
-4
x 10
-3
x 10
-------
TECHNICAL REPORT DATA
fPlcosr read lutlntclkms on the rrrcrsc before completing)
1. REPORT NO.
EPA-600/2-76-138 J
4. TITLE AND SUBTITLE
Coal Preparation Environmental Engineering Manual
7. AUTHOHIS)
David C. Nunenkamp
9. PERFORMING OR9ANIZATION NAME AND ADDRESS
J.J. Davis Associates
7900 Westpark Drive (Suite 915)
McLean, Virginia 22101
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
May 1976
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO
10. PROGRAM ELEMENT NO.
EHE623
11. CONTRACT/GRANT NO.
68-02-1834
13. TYPE OF REPORT AND PERIOD COVERED
Manual: 6/74-6/75
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES pr0ject officer for this manual is Mark J. Stutsman, Mail Drop
61, Ext 2851.
6. ABSTRACT
The manual provides an introduction to physical coal cleaning to individual!
outside of the coal preparation industry. Specifically, the manual covers the general
nature and characteristics of U.S. coals, provides an overview of the coal prepar-
ation plant, discusses the major equipment and processes currently in use in coal
preparation, identifies the primary waste streams found during the coal cleaning
operation, discusses the techniques of control currently applied to those waste
streams, and describes the contaminant removal potential of coal.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
oal
oal Preparation
nvironmental Engineering
ll.lDENTIFICRS/OPEN ENDED TERMS
Air Pollution Control
Stationary Sources
Physical Coal Cleaning
c. COSATI Field/Gioup
13B
08G, 21D
081
05E
8. DISTRIBUTION STATEMENT
Unlimited
19. ShCURI TY CLASS (flits Kcpurl/
Unclassified
20. St CumVV CLASS (Tliilipagrj
Unclassified
21. NO. OF PAGES
118
22. PRICE
EPA Form 2220-1 (9-73)
727
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