Dust Control Handbook for Industrial Minerals Mining and Processing

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A second regulation is a general industry standard established by OSHA in 29 CFR 1910.242(b),which states: "Compressed air shall not be used for cleaning purposes except where reduced toless than 30 psi and then only with effective chip guard and personal protective equipment."This regulation established the 30 psi limit for the maximum air pressure for the air spraymanifold.Because of these two federal standards, operations must file a petition of modification to theirMSHA District Manager to obtain approval to use this clothes cleaning system at their facility.Since this system has already been approved for use at other operations, obtaining approval forsimilar systems should not be difficult. Manufacturers producing the clothes cleaning system5can be contacted by those interested in taking advantage of this technology.HOUSEKEEPING PRACTICESAlthough good housekeeping practices might seem to be a minor or common sense issue, theycan be a significant factor in a worker's respirable dust exposure at mineral processingoperations. When housekeeping is performed properly and on a scheduled time frame, it can bea key factor in minimizing respirable dust exposures to workers. On the other hand, when it isnot performed, or performed improperly, it can have just the opposite effect. In one study, anexample of this was documented when a worker was dry sweeping the floor with a push broom.In this instance, the average exposure of a coworker located one floor up from the person3 3sweeping the floor increased from 0.03 mg/m before sweeping to 0.17 mg/m during, andimmediately after, the occurrence (Figure 8.4). Dry sweeping is discouraged as a viable cleaningtechnique because of the dust generated and liberated into the work environment [USBM 1986].Figure 8.4. Increase in coworker’s dust exposure one floor up from floor sweeping activities.5One manufacturer of the clothes cleaning booth technology is Clothes Cleaning Systems(http://www.cleanclothbooth.com/), which is selling the system that was developed under this cooperative workeffort.Controls for Secondary Sources 207
Spills of product material are a common occurrence at processing operations and when theyoccur, the initial removal of material is most often performed with a scoop, bobcat, or throughhaving workers using shovels. When this task is performed manually, the appropriate respiratoryprotection must be worn by workers.Once the bulk of this material is removed, or for general housekeeping, it is very effective towash down the facility with water on a regular basis. Ideally for this to work, the design shouldbe incorporated in during construction so that drains are installed and the floor is sloped correctlyto ensure that the water runs toward the drains. Although washing down is very effective, itmust also be noted that this can unintentionally increase respirable dust levels during the hosingprocess. The problem occurs when water strikes piles of accumulated fine material, which cancause dust to be liberated into the air. When washing down is being used as a housekeepingtechnique, it should be done shift by shift, or at least daily, to keep product from accumulating.In addition to washing down, the next most common housekeeping techniques are the use offloor cleaning devices and/or vacuum systems. Although both of these techniques are muchmore costly than washing down, neither typically generate or liberate significant levels of dustduring the cleaning process, as is the case with washing down.When considering floor cleaning options, there are many different manufacturers and companiesthat sell a vast array of different types of floor cleaning units. These units vary from ones that anindividual rides to smaller units that an individual walks behind (Figure 8.5). One area thatshould be closely investigated is the disposal of the contaminated material once it has beencollected. It would be counterproductive if the unit is very efficient during the floor cleaningprocess but contaminates employees when the unit is being cleaned or during disposal of theaccumulated material.Figure 8.5. Various types of floor sweep units used to clean dust-laden floors.In addition, there are many different types of vacuuming units. These can range from highcapacity,in-plant vacuuming systems with multiple collector pickup locations to portable tank-208 Controls for Secondary Sources
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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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Page 186 and 187: CHAPTER 6: BAGGINGThis chapter disc
Page 188 and 189: caused during manufacturing, includ
Page 190 and 191: Overall PerforationsThe use of over
Page 192 and 193: Figure 6.5. Open-top bag being load
Page 194 and 195: Bagging operators should be aware t
Page 196 and 197: Figure 6.8. Exhaust hood to capture
Page 198 and 199: In the original design, a single no
Page 200 and 201: The OASIS is a relatively simple de
Page 202 and 203: Figure 6.13. Bag storage shelves sh
Page 204 and 205: Figure 6.14. Bag and belt cleaner d
Page 206 and 207: other industrial application using
Page 208 and 209: The robotic arm automatic palletize
Page 210 and 211: For many years, this plastic wrappi
Page 212 and 213: warehouse location until a later ti
Page 214 and 215: used successfully to perform this c
Page 216 and 217: DUST CONTROL HANDBOOK FOR INDUSTRIA
Page 218 and 219: CHAPTER 7: BULK LOADINGDuring the b
Page 220 and 221: Figure 7.2. Loading spout discharge
Page 222 and 223: Cascading Loading SpoutFigure 7.5 i
Page 224 and 225: a seal at the entry and exit points
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: Figure 8.3. Test subject wearing po
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
Page 245 and 246: manually removing the bags and plac
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
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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 and 274: upon the wind velocity (or disturba
Page 275 and 276: Maximum size is the largest particl
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
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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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