Dust Control Handbook for Industrial Minerals Mining and Processing

Wet dust control methods for crushing operations, illustrated in Figures 4.10 and 4.11, involvewetting the process material before crushing, after crushing, or both. This is essentially treatingthe crushing operation as two transfer points, the feed side and discharge side. Crushing createssmaller sized material with an attendant increase in surface area, which will be dry. Thus,material wetted prior to crushing for dust control will likely have to be wetted again to addressthe additional dry surface area.Where dust control through water application is selected, recall that solid spray nozzles, or fullcone spray nozzles, produce larger drop sizes than hollow cone nozzles. Hollow cone nozzlesshould be used when dust suppression (reduction of airborne dust) is desired, with spray patternsarranged to cover the entire area of the dust cloud. When prevention of airborne dust is desiredin a static application such as a bin or hopper, full cone nozzles should be used with spraypatterns overlapping the entire surface of the material to be wetted. In a moving application suchas a conveyor, fan spray nozzles should be used with spray patterns oriented perpendicular toconveyor travel and overlapping approximately 30 percent of the fan width. Further informationon wet methods is found in Chapter 2—Wet Spray Systems.Figure 4.10. Illustration of a wet dust control approach with a transferchute/impact bed enclosure at a crusher loading operation.120 Crushing, Milling, and Screening