OH&S News

How belt support, seal systems can control dust hazards

Ineffective measures and failures in controlling silica dust emissions at many quarrying and bulk materials handling operations can cause serious consequences and health risks. Added to this are the maintenance clean-up costs and long term detrimental economic and environmental impact to surrounding residential communities.

It’s timely for quarry operators to tackle ongoing dust problems or risk disruption to their productivity and (worst case scenario) suspensions to planned developments/expansions, and threats to future viability of operations.

In the US, silica dust emissions have come under the spotlight at the Occupational Safety and Health Administration (OSHA), resulting in testing, data and discussions leading to standards being issued. The regulation sets out strict guidelines with the aim of minimising the risk of silicosis, chronic respiratory issues, lung cancer, kidney disease and other health conditions linked to exposure to concentrated levels of airborne silica dust over a long period, and details optimal risk mitigation practices and compliance.

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To date, Kinder Australia has advised materials handling operators of the dangers of uncontained dust emissions posing serious OHS issues – not only to staff but also to machinery and nearby communities. The fine airborne dust particles cause serious damage to personal health when inhaled. Further safety risks include slips, trips and falls in areas of poor access and visibility caused by dust. Dust can also reach areas beyond the site boundaries. It can contaminate delicate ecosystems, especially in wetlands and rivers, causing regulatory interest and rifts between nearby towns and the plant.

From an OHS perspective, it’s also worth highlighting that from February to May 2017, 3.8 per cent of all quarry improvement notices issued by WorkSafe Victoria related specifically to exposure to dust. When quarry operators come under examination, failure to comply can result in prosecution, fines and (worst case scenario) site closure.

For more than three decades, Kinder Australia has been at the forefront of delivering innovative dust control solutions for all bulk materials handling applications. The resulting K-Snap-Loc dust seal system is a high performance engineered polyurethane solution for practical and cost-effective improvements around dust control problems, and is suitable for all conveyor belt speed applications.

“The effective suppression of dust particles at the conveyor transfer points can also be achieved through the installation of skirting and containment,” Kinder Australia CEO Neil Kinder said.

“Dust control is not only about protecting people and the environment but the machines in and around facilities as well.”

The company’s installation of K-MotorShield motor covers and Capotex belt conveyor covers play a pivotal role in tackling and minimising dust emissions. Motor covers prevent environmental debris and particles destroying bearings, windings and brushes on drive motors. Belt covers allow easy access to the conveyor system at all times for ongoing maintenance, reducing labour and shutdown requirements.

Case study 1

Site inspections for a Victorian quarry producer identified major issues with dust emissions. The transfer point under the tertiary crusher was a source of excessive spillage and dust emission. After many years of service and increased load due to plant productivity increases, the belt was operating at full capacity. This resulted in the area flooding and not containing the crushed material.

Material turbulence generated a huge amount of dust in the tertiary crushing process, which was ultimately escaping and causing constant emissions from the conveyor belt skirting system. Dust had been reported to cause issues and blockages on the spray nozzles, and the site had attempted to wet the product, which only led to binding of the screens further along in the process.

With the vertical impact drop height from the cone crusher being 2.5m and a lump size of minus 60mm, the material was pooling and not moving in the direction of the conveyor belt.

A combination of conveyor belt sag and inconsistent conveyor idler profile resulted in an ineffective skirting system, therefore resulting in the dust emissions and spillage.

After conducting an in-depth evaluation, the quarry elected to overhaul the conveyor by fabricating a new tail section and followed recommendations to install the K-Impact belt support system, K-Sure belt support system, K-Ultra dual seal skirting system and a return vee plough with the aim of tackling the dust emission challenges head on.

To date, the project upgrade has delivered positive outcomes, with minimal dust reported from the skirting system. The only dust reported was observed to be appearing from another source, near the crusher discharge.

Case study 2

Based in south-east Victoria, the producer’s core activity is the extraction and provision of granite-based aggregates, of up to 40mm minus. Situated on the edge of reclaimed swampland, the quarried material has a high silica content and so the operations required effective dust suppression to meet OHS regulations in line with environmental policies, and to provide adequate working conditions for staff.

In the introductory phase, the quarry manager observed the existing rubber skirting was being used to contain conveyed material. The highly abrasive characteristics of the conveyed granite, in addition to the drop height of 2.5 metres, meant the rubber skirt was lasting only two months before it needed to be changed out and replaced. Containment of the fine dust particles was also highlighted as an area for improvement.

With prior knowledge of the K-Ultra dual seal, the quarry manager was confident there was no other product that combined its unique dual capabilities, ie:

  • The interior facing wear resistant layer of polyurethane exceeds the wear life of traditional rubber-only skirting.

  • The outer anti-dust integral moulding can adapt to belt vibration and maintain the correct pressure to effectively seal the belt.

A positive outcome was achieved, with the K-Ultra dual seal installation lasting about 12 months in regular production and suppressing the dust more effectively than the previous skirting.

The nature of today’s quarrying produces dust and lots of it, and best practice dust control measures need to be implemented to ensure the levels are industry standard compliant and which prevents harm to workers. Dust control systems currently available in the market vary greatly in terms of complexity and ease of implementation and are highly dependent on a site’s size, location and surrounding environment.

“Our experience and expertise has shown the return on investment from implementing effective dust control solutions can be realised quickly,” Neil Kinder said. “The real gains to a quarry operator can also be put in terms of continuous efficiency in productivity, and reducing the risk to personal safety and the environment.”

Source: Kinder Australia


1. Stiverson L. Clearing the air. In: Dry Bulk Magazine; 2(2), June 2017. Palladian Productions, UK; 43-48.
2. Thirwall B. Under control. Ibid; 49-52.

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