Australian Quarrying Industry – Workplace Health and Safety (Part Three)

In Australia, the approach to workplace health and safety in the context of our discussion is critically assessed from work involving hazardous quarry mine dust. Quarry mineworkers come in contact with a wide variety of hazardous dusts such as crystalline silica dust amongst many others that exist. The failure to adequately control and prevent exposure to silica dust associated with ineffective dust control systems can result in severe pulmonary conditions as inhalation of hazardous dusts break the respiratory protection barriers of quarry mine workers. Workplace health and safety in the Australian quarrying sector involves a range of legislative measures which fundamentally deal with preventing or controlling the exposure of quarry mine workers to a variety of health risks stemming from exposure to quarry mine dust. The ultimate goal of compliance with workplace health and safety standards is to achieve the best possible outcomes from the relationship of work to health and the effects of work on the work as obligated by the duty to care statutes of the employer in the mining operating license. The onus is on the quarry mining company to perform suitable and sufficient analysis of the work environment to ensure that health and safety risks associated with quarrying are reduced to the lowest extent reasonably practicable. As we broaden the discussion, the article seeks to evaluate Australian quarrying worker safety and health-related to crystalline silica dust generation, the legislation available and will be summed up with the role Global Road Technology products play in workplace health and safety at Australian quarrying sites. 

Growth driving growth

Australia’s population is projected to grow from by 6 million in 2030. Marked growth in Australia’s population also means an increase in public infrastructure requirements which rises the demands for heavy construction materials. The Australian Bureau of Statistics estimates that each Australian requires 7 tonnes per annum of quarry materials to support the building of roads, houses and infrastructure to service their needs. One kilometre of highway uses up to 25000 tonnes of crushed rock, one kilometre of suburban roadway requires 5000 tonnes of crushed rock, 750 tonnes of concrete for footpaths, kerbs and gutters and 450 tonnes of asphalt for road surfacing. One kilometre of railway requires 2000 tonnes of aggregates A high-rise building can use up to 1000 tonnes of aggregate per floor. Construction of a typical house, including a driveway and landscaping, uses about 110 tonnes of aggregate and 53 cubic meters of concrete. In the greater scheme of things, more quarrying is bound to happen, and it will require the effort of quarry mine workers to meet the demands of different industries that utilize the materials. Their exposure to different types of crystalline dust particles is the greatest challenge that needs to be addressed from workplace safety and health perspective. There is definitely a synergy between the incidence of health hazards and the demands for quarry materials to service all the needs for Australia’s public infrastructure. 

Dust – a health and safety issue

Given the high demand for heavy construction materials and public infrastructure, tackling the control of dust generated from quarrying sites in Australia has to take a comprehensive legislative approach. In hindsight strict regimes for dealing with the health risks associated with various forms of inhalable and respirable fractions which can take the form of quartz, cristobalite, tridymite, flint in different combinations. There are particulate matter fraction consists of small solid particles of respirable dust whose aerodynamic diameter is equal to or smaller than 10 microns. These natural materials mentioned are associated with human disease such as silicosis, silicotic nodules in the spleen, silico-tuberculosis, progressive pulmonary fibrosis whereas cristobalite-tridymite are more fibrogenic. They pose the greatest problems because they are not retained by barriers in the nose, such as cilia and mucus, and they penetrate through the respiratory tract. The type of activities that generate airborne respirable hazards such as crystalline silica dust includes underground non-metal mining, surface non-metal mining including aggregate and stone and solution mining. Our emphasis will be more on surface non-metal mining which includes aggregate and stone quarrying in Australia. Generally, mines situated in high silica rock content generate more dust than those in less silica rock areas and activities such as drilling, blasting and crushes produce the most dust in quarrying mines in Australia. 

Sources of dust and controlling legislation

The areas of concern with regards to workplace health and safety in relation to crystalline silica dust generation include drilling, blasting, sawing and wedging in natural stone quarries. Drilling generates the majority of the crystalline silica dust formed in processes employed in stone quarries. Similarly at aggregate quarries activities such as drilling, blasting, hydraulic impact hammering, crushing and sieving pose areas of concern for workplace safety and health as crystalline silica dust is generated from these activities. Most importantly, all quarries include hauling of raw materials and products in one form or another generate significant amounts of dust, especially in open pit quarries. Resource related activities such as storage and stockpiling also contribute to dust generation in areas where either dead or live stockpiles are kept in preparation for transportation from the quarry site to the respective area of use or need. Different methods have been employed to control silica dust generated from quarrying activities, these methods include use of water sprays as a form of wet dust suppression, encapsulation and housing, use of bitumen emulsions, lignosulphonates and salts. All these methods have their pros and cons with most of them having more limitations in their post-life, durability and sustainability of use. Legislation that governs workplace safety and health in Australia is under the framework set in the Commonwealth Work and Safety Act 2011 and it should be noted that while mine safety is a state-responsibility there exists an overlap in national uniformity in mine safety standards. Typically, we cite Queensland as an example where Mining and Quarry Safety Health Act 1999 was updated in 2020 for the guidelines for the management of respirable dust in mineral mines and quarries in Queensland. The updated guidelines emphasize and strengthen the need to have effective and reliable respirable dust mitigatory measures. Classification of reliability and effectiveness of controls is performed through a hierarchy of controls.

Examples of engineered solutions

Global Road Technology offers solutions at the apex of the hierarchy of control where it provides innovative solutions to completely eliminate exposure of quarry mine dust at its source before it can occur. For quarry mine roads, which generate the majority of dust, GRT Haul-Loc consisting of a specially formulated liquid polymer added to the watering trucks binds fugitive dust particles preventing them from being airborne dust. Given the chemistries of mineral aggregates, it is key to use a product which exhibits both hydrophobic and hydrophilic properties and GRT Activate super activates hydrophilic water to be able to interact with hydrophobic surfaces of mineral aggregates reducing the repulsion of fine dust particles to use of water alone. Workplace safety and health in Australia’s quarrying industry can be achieved through robust legislative approaches that constantly update but most importantly the solutions employed should target the apex of the hierarchy of controls which is to totally eliminate any type and form of dust at its source. 

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REFERENCES 

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