• Dust Management Technologies

The “cost of dust” to industry, the community and government can be quite significant, especially when considering the “big picture” of industrial dust emissions. For example, loss of material and export income; increasing workplace dust emissions; deteriorating ambient air quality and human health; residential complaints; increasing direct costs to industry (e.g. dust monitoring/testing, dust control equipment, housekeeping, maintenance, premature failure of components, shutdown of process/plant, loss of production, fines and prevention notices, project application rejections). These problems are exacerbated as larger quantities of bulk material are mined, processed and/or handled, and especially as the products become finer.

Some of the “traditional” ways to control fugitive dust emissions are summarized below:General ventilation (i.e. dilution of airborne dust concentration to acceptable levels).

• Containment (e.g. enclosures with integral filtration).
• “Push-pull” systems, using the “air-knife” or “air-curtain” concept.
• Dust suppression veneer (surface) treatment (e.g. rail wagons, trucks, stockpiles) or total particle treatment.
• Water spraying systems try to suppress airborne dust particles (e.g. see Fig. 1).
• Dust agglomeration (via ionization or ultrasonics).
• Local exhaust ventilation (LEV), also known as dust extraction, is one of the most common methods of dust control found in the industry.
• Wind barriers or diffusers (e.g. trees, walls, mesh) to help contain dust within industry boundaries.
• Vegetation (e.g. grass, shrubs) to help capture/trap airborne dust over large flat areas.

Most of these dust control measures really only treat the “symptoms” of dust generation and are considered as “protection” methods (i.e. they do not deal with the root causes of the problem). Also, some have been found to be relatively inefficient in terms of controlling fugitive dust emissions.