Dust Control Handbook for Industrial Minerals Mining and Processing

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Figure 2.10 illustrates a typical dump application with both dust suppression and preventionspray nozzles. In this case, dumping action produces airborne dust in the upper level of theenclosure and the impact of the falling material with the material already in the enclosure causesadditional dust to become airborne. The dust suppression spray nozzles in the headers at the topof the enclosure would be either air atomizing or hydraulic fine spray hollow cone nozzlesbecause of the smaller droplet sizes they produce. The dust prevention spray nozzles at thelower level of the enclosure would be hydraulic atomizing full cone nozzles because of theirlarger droplet sizes and full cone spray pattern for large surface area coverage.Figure 2.10. Typical loader dump dust control application.Figure 2.11 illustrates a typical conveyor application with both dust suppression and preventionspray nozzles. In this case, dust prevention spray nozzles are positioned above the movingconveyor to prevent dust on the material from becoming airborne. Dust suppression nozzles arepositioned at the discharge end transfer point to control airborne dust.Figure 2.11. Typical conveyor dust control application.Figure 2.12 shows the airborne suppression performance of the different spray nozzlesperforming at different operating pressures. As shown, atomizing sprays are the most efficientWet Spray Systems 69
for dust knockdown or suppression, followed by the hollow cone sprays. Hollow cone sprays area good choice for many applications in mineral processing operations because significantcoverage or wetting of the ore occurs, even at low moisture percentages. Full cone sprays wouldbe most applicable in the early stages of the process where the quantity of moisture added is notas critical. Flat fan sprays are most appropriate for spraying into a narrow rectangular spacebecause less water is wasted by spraying against an adjacent rock or metal surface.Figure 2.12. Airborne suppression performance of four types of spray nozzles[NIOSH 2003]. Atomizing nozzle is air atomizing, and hollow cone, full cone,and flat fan spray nozzles are hydraulically atomizing.Water QualityMAINTENANCE ISSUES WITH WET SPRAY SYSTEMSA fundamental consideration with any wet spray control system is the quality of the water beingsprayed, with water hardness and cleanliness being of greatest concern. If the available watersupply contains a high level of minerals, nozzle wear can be accelerated. The user shouldconsider nozzles fabricated in stainless steel if this condition is present. A high level of mineralsin the supply water can also introduce caking, which is a buildup of carbonates on the nozzle,and can increase the amount of maintenance required. Although it may not be possible tomodify the hardness of the water being sprayed, a properly designed and applied maintenanceprogram can help to minimize the adverse effects of high levels of minerals in the availablewater supply.If spray nozzles become plugged with sediment or debris, they render the spray systemineffective. Since the water to be used for spray systems at most mineral processing operationsis drawn from settling ponds, water purity is a concern. It is recommended to use a water70 Wet Spray Systems
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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
Page 48 and 49: Checklist for Hood EffectivenessThe
Page 50 and 51: A major disadvantage of the high-ve
Page 52 and 53: A common misconception when designi
Page 54 and 55: Avoiding Mitered Elbows Greater Tha
Page 56 and 57: Figure 1.13. Depiction of the horiz
Page 58 and 59: Figure 1.14. Typical design of grav
Page 60 and 61: Baghouse CollectorsBaghouse dust co
Page 62 and 63: Table 1.2. Emission factors for cru
Page 64 and 65: Figure 1.17. Typical design of a me
Page 66 and 67: Reverse Jet (Pulse Jet) CollectorsR
Page 68 and 69: Figure 1.20. Cartridge collector wi
Page 70 and 71: Wet scrubbers are particularly adva
Page 72 and 73: Electrostatic precipitators normall
Page 74 and 75: may be related to specific applicat
Page 76 and 77: times. When considering the depth o
Page 78 and 79: Figure 1.25. Demonstration of how a
Page 80 and 81: Figure 1.26. A typical fan performa
Page 82 and 83: Fan TypesThere are two basic types
Page 84 and 85: Figure 1.30. Typical centrifugal fa
Page 86 and 87: Figure 1.32. Typical roof ventilato
Page 89 and 90: DUST CONTROL HANDBOOK FOR INDUSTRIA
Page 91 and 92: The vast majority of dust particles
Page 93 and 94: Table 2.1. Particle/droplet size in
Page 95 and 96: Air Atomizing NozzlesAir atomizing
Page 97: Hydraulic Flat Fan NozzlesFigure 2.
Page 101 and 102: Nozzle MaintenanceFigure 2.14. Typi
Page 103 and 104: Accidental DamageInadvertent harm t
Page 105 and 106: NDT Educational Resource Center, Io
Page 107 and 108: 78 Wet Spray SystemsDUST CONTROL HA
Page 109 and 110: contains a piston which delivers ha
Page 111 and 112: produce an increase in the penetrat
Page 113 and 114: Dry DrillingDry drilling is accompl
Page 115 and 116: Circular ShroudIn contrast to the u
Page 117 and 118: The collector airflow has a more su
Page 119 and 120: Air-Blocking ShelfThe air-blocking
Page 121 and 122: dust emissions from mast lowering,
Page 123 and 124: This simple procedure of creating a
Page 125 and 126: Figure 3.15. Air ring seal used to
Page 127 and 128: Figure 3.17. Illustrations showing
Page 129 and 130: unsubstantiated due to the inconsis
Page 131 and 132: safety considerations may preclude
Page 133 and 134: Figure 3.22. A filtration unit, loc
Page 135 and 136: Miller S, Emerick JC, Vogely WA [19
Page 137 and 138: USBM [1995]. The reduction of airbo
Page 139 and 140: 110 Drilling and BlastingDUST CONTR
Page 141 and 142: Wet Control MethodsPREVENTION AND S
Page 143 and 144: Figure 4.2. Examples of compressive
Page 145 and 146: Figure 4.5. Illustration of a dry (
Page 147 and 148: 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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a seal at the entry and exit points
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REFERENCESBiere G, Swinderman RT, M
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200 Bulk LoadingDUST CONTROL HANDBO
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many years, as well as some new and
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Figure 8.2. Air spray manifold desi
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Figure 8.3. Test subject wearing po
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Spills of product material are a co
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epetitive dust leaks should not sim
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Effective Upward Airflow PatternThe
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Figure 8.8. Open-structure design c
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manually removing the bags and plac
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Figure 8.12. Increase in worker’s
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In other cases, an operation may wa
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Cecala AB, O'Brien AD, Pollock DE,
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224 Controls for Secondary SourcesD
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where C o = outside respirable dust
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minimal improvement in the cab's ai
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RECOMMENDATIONS FOR FILTRATION/PRES
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Effective FiltrationFigure 9.4. Res
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average decay times were between 16
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Figure 9.6. Filtration unit showing
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This table highlights a number of c
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NIOSH [2001b]. Technology news 486:
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upon the wind velocity (or disturba
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Maximum size is the largest particl
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Figure 10.4. Use of end-dumping wit
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conditions. Performance of each of
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A water truck, used to apply water
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Surfactants work by reducing the su
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which differed for the various site
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Figure 10.9. Self-tarping dump truc
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percent [Fryrear and Skidmore 1985]
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Figure 10.12. The armoring process
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A current method of stockpile forma
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Figure 10.15. Demonstration of how
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Chekan GJ, Cecala AB, Colinet JF [2
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Midwest Research Institute [1981].
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GLOSSARYAbrader. An implement used
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Carryback. Material that sticks or
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End-dumping. A process of spreading
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Open structure building design. A p
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Table bushing. A bushing used to se
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Delivering on the Nation’s promis
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