Industry Articles

Dust Control Techniques – Why Water Sucks!

Why are dust control techniques so important? Dust is a health and safety hazard which if not prevented at its source could lead to death because of pulmonary diseases such as silicosis, coal mine workers pneumoconiosis and lung cancer. Dust kills! Therefore, it is important to deliberate on why reliance on water alone is not pinpoint to the much-needed efforts of dust control at its source. Spraying water to control dust has been used for many types of dust and examples include coal dust, silica dust and metalliferous mineral dust. The intention is always good, but the limitations arise on the efficacy of water when one considers the chemo-physical interactions of hydrophilicity (water loving) and hydrophobicity (water hating). Australia is a water scarce country and climate change has increased pressure on depleted water resources which even gives more reason for water to suck given the ailing conditions in the country. Dust control in general uses so much water because the properties of water do not cater for the different chemistries of dust particles. In general, the state of water in its liquid form is susceptible to evaporation or temperature changes which renders it a huge problem in areas that have high temperatures and generate a lot of dust. In addition, water is a resource that also is vital for other industries hence competition for water relative to longevity when it is used increases pressures for such a scarce resource. When priority is getting water the often-forgotten risk is the life of workers and communities that become more susceptible to dust if water does not effectively control dust. It hits them twice, a lack of water for human consumption in their communities as well as prolonged exposure to dust particles which can lead to death. We evaluate why water sucks for dust control, what can make water for dust control and cement the discussion with a case for drill and blast dust control. 

Why does water suck for dust control?

The use of water sucks because of its high surface tension on interaction with dust particles of different chemistries. A water-loving dust particle is attracted to another water-loving substance in this case water. So, if the surface of the dust particle is water-loving chances are binding of the dust particle happens and it is taken out of suspension onto the ground. As easy as it sounds there is more to it than just attraction as majority of dust particles tend to be of a water-hating nature therefore the surface tension between water and the dust particles is very high. In practice, high surface tension means that binding properties of water are lost as the dust particles tend to repel the water. It’s a mere case of ineffective use of water which leads to loss of calorific value in coal for example, spoilages because of the porous nature of coal and with silica dust it just is a mere waste of water resources which costs dearly to keep the water trucks spraying water on different minerals, coal stockpiles just to mention but a few. Okay, let’s rewind the dust control ‘tape’ have we just sat in a chemistry class? Perhaps yes, we have its simple chemistry at play but its chemistry that is also met with resource scarcity, basic human needs for water and in all honesty finding sustainable solutions for dust control. Water alone is not sustainable as a dust control solution. Let’s take a deep breath or pause if you may call it. What then makes water work for dust control? Surely there must be innovation that has managed to answer this question and even come up with better alternatives. Yes, there is but is it easy for people to adopt it? We assume it must hence as GRT we will explain what can make water work in the following paragraphs. Brace yourselves for it. 

 

What can make water work for dust control?

Are environmental regulations, health and safety concerns or potential profit loss a concern right now?

The use of water additives is very effective in controlling dust. Additives reduce the surface tension of water and improve its ability to form wet surfaces and droplets. Water additives have created to provide an instant solution when made use of.  The use of water additives is ideal on mine sites, construction sites, farming, and even military sites amongst many other places where dust control is a priority. The water additives can be added to the water cart of the site, which already reduces the amount of daily water requirements. Making water work also includes having a film on haul roads, gravel roads, stockpiles that attract dust particles and sticks to the dust particles preventing them from being airborne. Binding and coating of surfaces to control dust can be achieved through use of liquid polymers in water. Synthesis of the polymeric component is performed to target saturation, penetration and bonding on the top layer even after water evaporates. The greatest motivation to use of liquid polymers has been the reduction in volume of water used which in the process saves time and costs. The need to prolong moist conditions has seen the use of biocompatible liquid polymers with success observed in post evaporative moisture compared to conventional water treatment. In dust suppression applications the choice of liquid polymer is based on biocompatibility, water solubility, phase at room temperature and how environmentally friendly it is. Interestingly, liquid amphiphilic polymers show significant dust control relative liquid hydrophilic polymers owing to the dual effect of the liquid state and the amphiphilicity of the polymer. Examples are GRT: Haul-Loc is the mining and resource sector version of liquid polymer available. It reduces the water required by 50% with up to five-fold improved duration of dust control sustenance compared to use of water alone. 

A case for drill and blast dust control

There are various means by which dust can be controlled. This is to ensure that it does not harm mine workers and local communities from effects of inhaling dust which can cause some vital damage to their pulmonary system. Dust should be dealt with at its source. In the light of the recently introduced drill and blast dust control product GRT 12X we focus on making water work through application of surface-active agents. The mechanism of action for surfactants in drill and blast dust control is entirely dependent on adsorption that occurs on the interface between the surface-active agent and the drill cutting surface. The surface is primarily hydrophobic in nature with secondary hydrophilic sites hence the amphiphilicity of surface-active agents enables a dual mechanism. This lowers the surface tension of water whilst converting the drill cutting surface to hydrophilicity via adsorption onto the hydrophobic sites. The surface-active agent solution succumbs to physical changes as a result of the decrease in surface tension with increased concentration of surface-active agent until a point is reached. At this point it remains relatively constant as the surface-active agent molecules form a unimolecular layer on the surface. Overall, GRT 12X captures the fine, hazardous dust drilling generated at its source, preventing it from becoming an airborne hazard. The addition of GRT: 12X to your drill water changes its nature almost instantaneously, capturing and encapsulating the dust within the water. 

So why does water suck? Water sucks for dust control because it has limitations to its interactions with different dust particles and its scarcity piles up pressure on other industries which are in dire need of water. GRT offers water saving solutions in addition to innovatory dust control solutions that offer long-lasting client benefits. 

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REFERENCES 

Troy Adams

Troy Adams is the Managing Director of Global Road Technology (GRT) Specialising in Engineered Solutions for Dust Suppression, Erosion Control, Soil Stabilisation and Water Management. A pioneering, socially conscious Australian entrepreneur, Troy Adams is passionate about health and safety and providing innovative solutions that are cost-effective to the mining industry, governments and infrastructure sectors. Troy is also a tech investor, director of companies like Crossware, Boost, Hakkasan, Novikov and more.

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