Fugitive dust emissions are a universal problem for the mining industry.
While the industry has done a lot to combat the problem, evolving community standards mean the bar is constantly being set higher.
Fugitive dust emission can occur during any of the processing steps, during transportation or storage, as such dust should be tackled in a holistic and integrated approach and not be treated as just a problem for the safety, environment, production or operation teams to manage – everyone has a responsibility.
Once dust particles are generated and become airborne, it does not matter which part of the site it originated, it becomes a problem for the whole site.
While there are many different types of dust suppression products available, the underlying principle by which these agents work is the same.
They are used to change the fundamental properties of the dusty material by increasing the size or density of the particles; agglomerating the smaller particles; and forming a protective layer or crust on the surface of the material.
All of these factors make it is less susceptible for particles to become and remain airborne. Generally, dust suppression agents are used as a surface or bulk material (total particle) treatment.
Every type of dust suppression product comes with its own set of features, advantages and disadvantages. Most of the products are derived from either synthetic polymer products; water absorbing salts; petroleum based products; organic based products; electrochemical products; clay based products; or enzyme based products.
Water is also commonly used as a dust suppressant.
However the disadvantage is that the effect is usually short lived and usually lost when the water evaporates.
Also water can only be used regularly where there is an abundant supply.
Over the years, surfactants or wetting agents have also been referred to as dust suppression agents.
This is a common misconception as surfactants are additives that are used to treat the water by changing its surface tension to allow it to better wet and penetrate hydrophobic materials.
So when it comes to choosing suppression agent for your dust problem, unfortunately there is no one size fits all solution. Your choice will depend on a number of factors such as the type of material and its properties being treated; how and where the dust is being generated; the impact on the handling properties and end use of the material; the location, climate and weather; environmental considerations; occupational health and safety rules and regulations
the cost of the dust suppression agent, the equipment, labour, running and other associated costs; and finally how easy is it to use.
As you can see it can be a complex issue when it comes to choosing a dust suppression agent.
A whole plethora of factors also need to be considered even before you get to the crucial question of: how does the dust suppression agent perform in a particular application?
Unfortunately, there is no simple answer to this question either. There are currently no standard methods for testing dust suppression products so it is important that dust suppression products undergo proper scientific evaluations both the laboratory and in the field as part of the selection process. Laboratory tests provide a controlled environment for side by side comparisons of different products.
Once the products have been short-listed, laboratory tests can also help optimise variables like the concentration of product to be used under different conditions and the dust control performance that may be expected. Properly conducted laboratory tests can reduce the amount of testing in the field, disruptions on-site and costs.
In an effort to address some of these issues around dust suppression products, collaborative research is being conducted by DuPont and the University of Wollongong in a project that is also supported by the Australian Research Council (ARC).
The project hopes to establish a unified approach to testing of dust suppression agents and also to develop dust suppression agents that are environmentally sustainable as well as effective.
Overall there are a range of factors you need to consider when choosing the right dust management product for your problem. Because there is no one size fits all solution, it's important to look at the type of material you are treating, weather conditions, OH&S regulations, costs and at the end of the day, how easy it is to use. Choosing reputable and knowledgeable suppliers or consultants who understand dust suppression agents, dust emissions and your specific issues, can also help guide you through the maze of factors to assist your selection of the best product for your problem.
The benefit when you get it right can be a simple and cost effective solution that solves your dust problem.
*Leong Mar is the leader of the dust management team at DuPont Sustainable Solutions.