Dust Control Handbook for Industrial Minerals Mining and Processing

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oad maintenance, reduce equipment maintenance cost, and will aid in effective dustcontrol and increased tire life. In particular, dust control will be augmented from areduction of fine material generated and through an increase in the longevity of dustsuppressants.When a vehicle travels over a haul road, the wheels exert forces on the road surface. Ofall the forces, the normal shear stresses created by the vehicle are the most critical. At thelocation of the wheel, the road is put into compression. Once the wheel passes thislocation, the road rebounds to its initial position through tension. On a properly designedroad, this compression and tension cycle will occur within the elastic limits of the roadstructure.Permanent deformation of the road can occur if it is not properly designed. Roadsconstructed of weak materials will readily degrade, which can produce fine material thatcan be entrained by mobile equipment traveling the road. Roads constructed of the propermaterials will degrade less rapidly, which in turn lessens the dust emission potential of theroad over the same period of use. Additionally, road failure will cause any dustsuppressant to exceed its bonding strength, thereby reducing the effectiveness of thesuppressant. Generally, dust suppressants work by forming a layer, or crust, over the topof the road. If the bonding strength of the dust suppressant is exceeded, the suppressantwill break up, deteriorate, and wear away.Materials selected for road construction must possess certain physical properties. Theyare: resistance to wear, soundness, maximum size, particle shape, and gradation [MidwestResearch Institute 1981].A high resistance to wear is desired for the road material. It should be hard andtough such that it will not be easily disintegrated under traffic load. The resistanceto wear can be measured by conducting abrasion tests such as the Los Angeles7Abrasion test. Generally, the most desirable materials include granite orlimestone. Soft and unsound materials such as shale, coal, mica, or vermiculiteshould be avoided as the use of such material will lower the road's strength anddurability.Soundness represents the ability of the material to withstand climatic conditions.A material is desirable if it can resist weathering. Materials that are weak,extremely absorptive, easily cleavable, swell when saturated, or are susceptible tobreakdown through natural weathering processes are not recommended for roadconstruction.7The Los Angeles Abrasion test provides information on aggregate resistance to crushing, degradation, anddisintegration from activities such as manufacturing, stockpiling, production, placing, and compaction.Testing is conducted by placing a coarse aggregate sample in a rotating drum with steel spheres. As thedrum rotates the material degrades by abrasion and impaction, with itself and with the spheres. Once the testis complete, the calculated mass of aggregates that has broken apart to smaller sizes is expressed as apercentage of the total mass of aggregate. Lower Los Angeles Abrasion values indicate that the aggregate istougher and more wear resistant to abrasion. Specifications for the test can be found in AASHTO T96 orASTM C 131 "Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in theLos Angeles Machine."Haul Roads, Stockpiles, and Open Areas 245
Maximum size is the largest particle size allowable in the road material. Generallyit is undesirable to use aggregate sizes larger than 1 inch for the surface course, inorder to maintain ease of maintenance with the road grader.Particle shape of the road material affects the stability, density, and durability ofthe road surface. Shapes which contain angular and rough-surfaced material resultin good interlocking and produce a desirable road surface.Gradation is the distribution of particle sizes throughout the road material. Awell-graded aggregate material contains a good representation of particle sizefractions from large to small sizes of material. An acceptable aggregate particlesize distribution of a material for structural purposes is generally represented byEquation 10.1 [National Stone Association 1991]:Pnd100 (10.1)Dwhere P = percent by weight finer than the sieve;d = sieve opening dimensions (inches) where common sieve sizes are 2-inch,1-inch, 3/4-inch, 3/8-inch, No. 4 (0.187 inches), No. 40 (0.0165 inches), and No.200 (0.0029 inches);D = maximum size of aggregate, inches; andn = an empirical gradation exponent ranging from 0.33 to 0.5. Generally 0.5represents the maximum density of material.In addition to possessing the appropriate material properties, a properly constructed roadwill consist of three components: subgrade, subbase, and wearing surface. These featuresare displayed in Figure 10.2. The American Society for Testing and Materials (ATSM)and the American Association of State Highway and Transportation Officials (AASHTO)have standards which define the minimum properties required.Figure 10.2. Cross section of haul road.The subgrade is the underlying soil or rock that serves as the foundation of the road. It isimportant because it supports the entire load of the vehicles traveling the road. There aretwo techniques for maximizing subgrade strength: compaction at optimum moisture andadequate drainage. Most subgrade soils will compact to their maximum density at a givenmoisture. To achieve this, the subgrade area should be scarified prior to adding water tothe location. Then compaction is generally accomplished using a vibratory compactor246 Haul Roads, Stockpiles, and Open Areas
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Report of Investigations 9689Dust C
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FUNDAMENTALS OF DUSTCOLLECTION SYST
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Minimizing Field Fits and Welds ...
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Recommendations for Proper Wet Dril
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CONTROL TECHNOLOGIES FOR FILLING 50
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Effective Filtration ..............
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ILLUSTRATIONSFigure 1.1. Relationsh
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Figure 3.2. The air and water flow
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Figure 9.5. Problem created by heat
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UNIT OF MEASURE ABBREVIATIONSUSED I
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Robert J. Franta, Quotation Enginee
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silica. Quartz is the most common s
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DUST CONTROL HANDBOOK FOR INDUSTRIA
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CHAPTER 1: FUNDAMENTALS OFDUST COLL
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The shape of particles affects how
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EXHAUST SYSTEMS DESIGNAll exhaust s
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stripping, which allows workers to
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When using the air quantities in Ta
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X = distance in feet from the face
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Checklist for Hood EffectivenessThe
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A major disadvantage of the high-ve
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A common misconception when designi
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Avoiding Mitered Elbows Greater Tha
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Figure 1.13. Depiction of the horiz
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Figure 1.14. Typical design of grav
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Baghouse CollectorsBaghouse dust co
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Table 1.2. Emission factors for cru
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Figure 1.17. Typical design of a me
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Reverse Jet (Pulse Jet) CollectorsR
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Figure 1.20. Cartridge collector wi
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Wet scrubbers are particularly adva
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Electrostatic precipitators normall
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may be related to specific applicat
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times. When considering the depth o
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Figure 1.25. Demonstration of how a
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Figure 1.26. A typical fan performa
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Fan TypesThere are two basic types
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Figure 1.30. Typical centrifugal fa
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Figure 1.32. Typical roof ventilato
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The vast majority of dust particles
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Table 2.1. Particle/droplet size in
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Air Atomizing NozzlesAir atomizing
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Hydraulic Flat Fan NozzlesFigure 2.
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for dust knockdown or suppression,
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Nozzle MaintenanceFigure 2.14. Typi
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Accidental DamageInadvertent harm t
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NDT Educational Resource Center, Io
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78 Wet Spray SystemsDUST CONTROL HA
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contains a piston which delivers ha
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produce an increase in the penetrat
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Dry DrillingDry drilling is accompl
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Circular ShroudIn contrast to the u
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The collector airflow has a more su
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Air-Blocking ShelfThe air-blocking
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dust emissions from mast lowering,
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This simple procedure of creating a
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Figure 3.15. Air ring seal used to
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Figure 3.17. Illustrations showing
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unsubstantiated due to the inconsis
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safety considerations may preclude
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Figure 3.22. A filtration unit, loc
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Miller S, Emerick JC, Vogely WA [19
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USBM [1995]. The reduction of airbo
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110 Drilling and BlastingDUST CONTR
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Wet Control MethodsPREVENTION AND S
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Figure 4.2. Examples of compressive
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Figure 4.5. Illustration of a dry (
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Figure 4.6. Illustration of a dry (
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Wet dust control methods for crushi
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Work Practices to Minimize Dust Exp
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Some specialty grinding operations
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should be frequently inspected for
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Open screen decks slowly to allow i
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CHAPTER 5: CONVEYING AND TRANSPORTT
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Figure 5.3. Basic depiction of mate
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that the material falls before land
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Figure 5.10. Skirtboard used within
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CarrybackMaterial that sticks or cl
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CONVEYOR DESIGN AND MAINTENANCE ISS
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Figure 5.15. Conveyor transfer encl
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High-volume, high-pressure sprays s
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Figure 5.19. Depiction of a bucket
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Figure 5.21. Depiction of two types
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Figure 5.25. Venturi eductor utiliz
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CHAPTER 6: BAGGINGThis chapter disc
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caused during manufacturing, includ
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Overall PerforationsThe use of over
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Figure 6.5. Open-top bag being load
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Bagging operators should be aware t
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Figure 6.8. Exhaust hood to capture
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In the original design, a single no
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The OASIS is a relatively simple de
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Figure 6.13. Bag storage shelves sh
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Figure 6.14. Bag and belt cleaner d
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other industrial application using
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The robotic arm automatic palletize
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For many years, this plastic wrappi
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warehouse location until a later ti
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used successfully to perform this c
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CHAPTER 7: BULK LOADINGDuring the b
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Figure 7.2. Loading spout discharge
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Cascading Loading SpoutFigure 7.5 i
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Page 226: REFERENCESBiere G, Swinderman RT, M
Page 229 and 230: 200 Bulk LoadingDUST CONTROL HANDBO
Page 231 and 232: many years, as well as some new and
Page 233 and 234: Figure 8.2. Air spray manifold desi
Page 235 and 236: Figure 8.3. Test subject wearing po
Page 237 and 238: Spills of product material are a co
Page 239 and 240: epetitive dust leaks should not sim
Page 241 and 242: Effective Upward Airflow PatternThe
Page 243 and 244: Figure 8.8. Open-structure design c
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Page 247 and 248: Figure 8.12. Increase in worker’s
Page 249 and 250: In other cases, an operation may wa
Page 251 and 252: Cecala AB, O'Brien AD, Pollock DE,
Page 253 and 254: 224 Controls for Secondary SourcesD
Page 255 and 256: where C o = outside respirable dust
Page 257 and 258: minimal improvement in the cab's ai
Page 259 and 260: RECOMMENDATIONS FOR FILTRATION/PRES
Page 261 and 262: Effective FiltrationFigure 9.4. Res
Page 263 and 264: average decay times were between 16
Page 265 and 266: Figure 9.6. Filtration unit showing
Page 267 and 268: This table highlights a number of c
Page 269 and 270: NIOSH [2001b]. Technology news 486:
Page 271 and 272: DUST CONTROL HANDBOOK FOR INDUSTRIA
Page 273: upon the wind velocity (or disturba
Page 277 and 278: Figure 10.4. Use of end-dumping wit
Page 279 and 280: conditions. Performance of each of
Page 281 and 282: A water truck, used to apply water
Page 283 and 284: Surfactants work by reducing the su
Page 285 and 286: which differed for the various site
Page 287 and 288: Figure 10.9. Self-tarping dump truc
Page 289 and 290: percent [Fryrear and Skidmore 1985]
Page 291 and 292: Figure 10.12. The armoring process
Page 293 and 294: A current method of stockpile forma
Page 295 and 296: Figure 10.15. Demonstration of how
Page 297 and 298: Chekan GJ, Cecala AB, Colinet JF [2
Page 299 and 300: Midwest Research Institute [1981].
Page 302 and 303: DUST CONTROL HANDBOOK FOR INDUSTRIA
Page 304 and 305: GLOSSARYAbrader. An implement used
Page 306 and 307: Carryback. Material that sticks or
Page 308 and 309: End-dumping. A process of spreading
Page 310 and 311: Open structure building design. A p
Page 312 and 313: Table bushing. A bushing used to se
Page 314: Delivering on the Nation’s promis
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