Industry Focus: Dust Suppression and Modelling
The problem of dust emissions from coal mining has been thrust back into the spotlight following the diagnosis of a Queensland miner with Coal Workers’ Pneumoconiosis (black lung) in November last year. There have been more than five cases of black lung officially diagnosed since then, leading to the industry, government and stakeholders to review procedures surrounding dust exposure. Due to the increasing pressures on miners to focus on health & safety, reducing coal dust emissions is set to be a more prevalent issue moving forward. Fortunately for Australia, we have a number of Mining Equipment, Technology and Services (METS) companies who have the capabilities and expertise in the areas of dust suppression and modelling.
Black lung is a chronic lung disease caused by inhaling coal dust particles, which accumulate and the lungs turn from pink to black. The incurable disease was thought to have been eliminated in the 1980s, leaving current medical resources and training spread thin. The re-emergence of black lung is believed to be due to a range of factors, including: complacency from the mining industry and government who thought the disease was eradicated, a backlog of workers who hadn’t received appropriate safety check-ups and a lack of qualified medical personnel with the expertise in diagnosing black lung. These issues have made prevention of dust emissions at mine sites and during transportation even more important to reducing the chances of miners contracting the disease.
Coal dust becoming airborne does not only impact miners at the mining and processing stage, but also affects the local community. There have been numerous instances of townships impacted by mines, power plants, shipping facilitates, coal trains or trucks that release airborne particles that enter water sources, devalue property or even cause combustion. As part of the new industry climate where miners must be conscious of their effect on the local community and the environment, it is essential that these problems are mitigated or eliminated, with technology to play a major role in this. Social license to operate is one of the biggest concerns for mining CEOs and boards, and black lung cases hitting the news headlines could impact on this.
Miners must formulate a dust management plan that incorporates each stage of the coal value chain. Digital technologies and software can be used to create models of coal dust emissions and explosions. These enable miners to look at where the sources of coal dust emissions are on their particular mine site (e.g. wind erosion from stockpiles or the loading of cargo ships) and they can make changes to nullify this, before it becomes a catastrophic issue for the company.
There are a range of strategies, products and techniques that can be used in the suppression or prevention of coal dust. These will vary in effectiveness depending on an array of factors, such as how and where the dust is generated, associated costs and environmental and health and safety regulations. It is often most beneficial to use a combination of techniques to ensure the maximum amount of dust control.
Wet systems and water sprays are widely-used due to their effectiveness, easy implementation and being comparatively economical. They work by increasing the moisture content of the particle to prevent it from becoming airborne, or can be added to the air to capture those particles that are already airborne.
Australian Diversified Engineering (ADE) have an impressive track record with their dust suppression solution. Eric Tomicek (ADE) recently spoke about their solution, especially in relation to haul roads, stating “In an open-cut operation, haul roads can count for approximately 40% of the total dust emissions on site. Miners use water trucks to spray the roads, but this can create overwatering, and the risk of truck slides and vehicle rollovers. ADE created the ECO Spray Premium to manage this, as it has in-built data logging and online tracking which monitors water application”. Eric also touched on another ADE innovation, the ECO Spray Forecast which “Uses local weather data and mine site information to forecast daily water truck requirements and identify when dust may go uncontrolled”.
Enclosures, such as covered conveyors and closed cabs on vehicles, and ventilation and filtration can also be used to minimise dust exposure. There are also a range of administrative controls that can assist in reducing dust exposure, such as ensuring regular maintenance of vehicles and mine workings, establishing dust exclusion zones and limiting the duration of workers’ exposure to particles.
Austin Engineering have been active in the area of dust minimisation during dumping. They designed the Westech Flow Body that controls the flow of material out of the dump truck body during dumping, reducing dust generation and wear on the body.
With the rise in cases of black lung and increasing pressures on miners with regards to health and safety and environmental considerations, it is once again being acknowledge as critical to do something about dust management on mine sites in Australia.
Sheldon Varcoe, Membership Services Officer, Austmine