Boral understands that communities close to our quarry sites have questions and concerns regarding possible inhalation exposures to airborne Crystalline Silica. The information provided in this fact sheet explains how Boral manages the risk of Crystalline Silica to our staff and to the community.  

What is RCS?  

Crystalline silica is a natural substance found in sand, stone, concrete, and mortar. It is also used to make a variety of products including artificial stone products (such as kitchen and bathroom benchtops), bricks and tiles. When workers process materials containing crystalline silica with power tools or other machinery, airborne dust particles can be generated that are small enough to lodge deep in the respirable region of the lungs and cause serious illnesses or diseases - including silicosis. These dust particles are called Respirable Crystalline Silica – or ‘RCS’.    

Different types of rock and rock products can contain different amounts of crystalline silica, for example:   

The rock present at the Reedy Creek site is Greywacke, which is a variety of sandstone, generally characterized by its hardness, dark colour, and angular grains of quartz, feldspar, and small rock fragments or sand-size lithic fragments set in a compact, clay fine matrix. The predominant form of crystalline silica is quartz, which makes up less than 30% of greywacke rock.  

RCS in the air may appear to be concerning, especially as in recent years where there have been reports regarding health issues caused by respirable crystalline silica and the harm experienced by workers in the kitchen benchtop industry.  

However, whilst a high proportion of quarried products contain some crystalline silica, this does not mean that the dust generated, during processing and handling quarry materials, is RCS.   

Respirable Crystalline Silica (RCS) is a small fraction of the dust that is generated at the quarry.  

If the handling and processing of crystalline silica substances is controlled at the source, and workplace exposure limits and environmental dust criteria are appropriately managed, there is no risk of community exposure.  

Dust Monitoring  

At Boral, we undertake regular dust monitoring at the plant, as well as at the boundary. Monitoring at the plant site helps us to better understand where potential inhalation risks exist during normal operations as well as during maintenance shut-downs.  Boundary dust monitoring lets us know if any airborne dust could potentially leave the site and potentially impact on the local community.  Both types of monitoring help us to better understand when and where we need to improve our dust controls. 

We also undertake regular personal dust monitoring on our workforce to check that their potential dust exposures are kept as low as reasonably achievable, and where levels are elevated, the workers are suitably protected by a high level of respiratory protection.  All workers also undergo regular health checks, in accordance with the quarrying regulations.  

Weather Monitoring  

Meteorological station and airborne particulate monitors are sometimes installed on site to directly measure parameters such as wind speed, wind direction and airborne particulate matter.  Alerts are set for wind speed and airborne particulate levels; which allows the Quarry or Mine Manager to make informed decisions during operations and curtail or cease operations during adverse wind and weather conditions, as required.  

Additional Mitigation Measures  

Effective engineering and dust mitigation measures, consistent with industry best practice, are used at Boral sites including:  

• Pathway controls which keep dusts generated during material processing and conveying enclosed. 

• Suppression systems such as misting water sprays and surfactants, are used on crushing and screening equipment.   

• Dust extraction systems are used on some quarries (where plant designs allow). 

• Limiting or ceasing dust generating activities during periods of high winds or extremely dry weather.   

• Applying water and dust suppressant to haul roads, processing equipment and stockpiles at the sites in accordance with accepted best practice.   

• Unsealed internal roads are appropriately constructed and graded where necessary to limit dust lift-off from transportation activities.   

• Adoption of suitable speed limits on unsealed roads.   

• Restricted load size to ensure materials do not extend above truck sidewalls and ensure all loads leaving the sites are fully covered.   

• Public roads are inspected each day at main entry and exit points to and from areas where construction activities are taking place and regular road sweeping is undertaken to clean any tracked material.   

• Dust management training and awareness is undertaken within the site team.   

• Appropriately assessing on-site weather conditions prior to undertaking blasting to ensure no blasts occur in unfavourable conditions (such as high winds) so dust emissions are effectively minimised.   

• Adhering to progressive disturbance and progressive stabilisation processes, where achievable.   

• For any new development applications an Air Quality Impact Assessment (AQIA) is commissioned to undertake predictive modelling of particulate matter dispersion from the Quarry or mine site.  

Regulation  

All Boral quarry sites are extensively regulated by QLD government departments, including (but not limited to) environment, mining, WHS, and local council, to assess the effectiveness of site dust controls and our operating management systems.