Dust-related lung diseases occur as a result of inhaling varying amounts and concentrations of respirable dust. This can happen over a short or long period of time. In the mining industry, there are different types of dust and similar hazards depending on the nature of mining activities. These include:
- rock dust
- silica dust
- coal dust
- naturally occurring asbestos/asbestos-like materials
- diesel particulate matter
- welding fume
- finely powdered materials.
Dust related lung diseases depend on the type of dust a mine worker is exposed to. Coal workers’ pneumoconiosis is caused by exposure to coal dust. Silicosis is caused by exposure to respirable crystalline silica. Different stages of dust-related lung diseases exist depending on the longevity of exposure the effects can be acute, chronic and at times fatal. In essence exposure to dust is a health hazard.
Preventing dust-related lung diseases is non-negotiable but is a process that requires understanding the nature of the dust and its properties. Different methods are used to measure and prevent exposure to dust. Their effectiveness is subject to questions. How much do they tell in relation to the reality of preventing dust-related lung diseases? Lives are at risk if dust is not managed at the source. Cutting dust exposure at the source is the only way to prevent dust-related lung diseases. This article specifically discusses dust related lung diseases from silica and coal with a focus on why and how dust is a problem.
WHS – a closer look into Queensland.
The Queensland Mines Inspectorate published the Mines safety bulletin no.151 in 2015. The title was ‘Preventing dust-related lung diseases’. This was at a time when coal mine workers pneumoconiosis resurfaced in Queensland. The recommendations from the safety bulletin related to mine operators. Auditing and reviewing effectiveness of site safety and health management systems was recommended. Implementation of these systems intended to cut the risk of lung disease to mine workers. Site senior executives had to review mine management plans for dust including regular monitoring and assessment of the working environment that covered mine procedures, equipment and installation. All this was to cut worker exposure to unhealthy dust levels. However, prior to 2015 there had been legislation governing the prevention and protection of mine workers to dust levels. Section 135 of the Mining and Quarrying Safety and Health Regulation is one of them. Section 89 of the Coal Mining Safety and Health Regulation also part of the legislation. Both required workers’ exposure limits adherence. It was against the law to exceed exposure limits related to specific dust hazards. Was that enough to prevent dust-related lung diseases? Unfortunately not. We deliberate more on dust-related lung diseases to understand the challenge at hand.
The dangerous properties of respirable crystalline silica and coal dust
The environmental fate of crystalline silica in the form of quartz is persistent as it is stable under most earth surface conditions. It also has low solubility at varying pH, salinity and redox potential. The major health risk for crystalline silica is via occupational exposure. exposure to coal depends on the mining technique. The coal dust exposure in underground longwall mining tends to be more compared to open-cut mining. Exposure routes and pathways are by inhalation for both coal and silica dust. At very small particle sizes (< 10 microns) these dusts become aerosolized. They can enter the respiratory tract where they deposit along the tracheobronchial tree. Deep deposition can occur in the alveoli where gas exchange takes place.
Are environmental regulations, health and safety concerns or potential profit loss a concern right now?
The mechanism of action of silica dust differs from that of coal dust. Their chemistries are different so they act different in the respiratory system. Crystalline silica has very low solubility in human body fluids. Macrophages cannot completely clear silica dust. On ingestion of silica dust, the macrophage cell membrane are prone to damage. This leads to macrophage death. It reduces their role to clear silica dust from the respiratory system. Crystalline silica is ingested into a cell. Then free radical oxygen species are generated from the surface of the particle. Lipid peroxidation and membrane damage happens followed by cell death. Deposition of coal dust in the lung results in lung tissue reaction. Advanced stages of coal mine workers’ pneumoconiosis is severe. It results in tough, fibrous tissue deposits in the lungs. This interferes with ability of lungs to expand. This affects the normal exchange of oxygen and carbon dioxide making breathing difficult.
There is no cure – so prevention is the only option
Dust kills. Dust causes life-shortening lung diseases. It reduces the quality of life of those exposed. Prevention of dust-lung diseases should take an integrated approach involving mine operators, governments and mine workers. Unfortunately where lives are a concern, prevention is not better than cure. Prevention of exposure to dust at its source save lives. There is no cure to dust lung diseases. It is a matter of life and death.
Occupational exposure includes measuring workers’ exposure by sampling the work environment. It also involves collecting personal dust levels. Our opinion is that dust should be dealt with at the source. As a matter of fact, we feel it is non-negotiable. The first and most critical line of safety and health is dealing with dust at its source. Monitoring should be only undertaken as part of a management technique geared towards mitigation – not data gathering. It’s a matter of a non-compromise approach to preventing dust-related lung diseases, sparing the impact on work-related deaths to workers, their families and communities.
GRT approach to industry best practice.
Recently we penned an article on Silica Dust – Industries At Risk. Mineral aggregate dust require a chemical dust suppression product which exhibits both hydrophobic and hydrophilic properties. GRT Activate super activates water enabling it to interact with hydrophobic surfaces of mineral aggregates – preventing the propagation of airborne silica dust. In coal dust applications, we recommend GRT Activate UG. This concentrated additive is specific for the coal face. It super activates water which enables it to bind coal dust particles. Its use is for coal dust control in longwall and continuous miner operations. It does not alter coal-burning properties. Its application prevents coal dust from conveyors, stockpiles or coal in transit. GRT encourages you to take part in the discussion about how to prevent dust-related lung diseases as an industry.
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REFERENCES
Sokas, R.K., and Sprince, N.L. 2008. Occupational Health: Overview. Elsevier Inc.
Southard et al. 2014. Silica, Crystalline. Encylopedia of Toxicology. 4. Elsevier Inc.
