Dust Control for Mobile Crushing & Screening Plants

Dust Control for Mobile Crushing and Screening Plant: Practical Solutions for the Hardest Dust Problem on Site

Mobile crushing and screening plants are the workhorses of the quarry, construction and contract mining sectors. They produce the aggregate, road base, drainage rock and fill materials that every project needs. They also generate some of the most concentrated and most hazardous dust on any site.

Every stage of the mobile processing train — from the feed hopper through the jaw, cone or impact crusher, across the screens and along the product conveyors — fractures rock and liberates respirable dust particles. In hard rock operations, those particles contain crystalline silica at concentrations of 20–70% by weight. The dust is generated continuously at high rates, in close proximity to operators and adjacent workers, in an open-air environment with no permanent enclosures or extraction systems.

Fixed processing plants in established quarries and mines can deploy permanent solutions: enclosed crushers, ducted extraction systems, baghouse filters, sprinkler arrays connected to reticulated water supply. Mobile plant, by definition, cannot. The plant is relocated periodically — between sites, between pits on the same site, or between construction phases. Dust control solutions must be portable, quick to deploy, independent of fixed infrastructure, and effective from the moment the plant starts producing. Water sprays are fitted as standard, but plain water alone is demonstrably insufficient against the finest, most hazardous fraction of the dust.

This article covers the dust sources specific to mobile crushing and screening, the regulatory framework now applying to every mobile plant operation in Australia, why water alone falls short, and how chemical activation of the existing spray system delivers the performance improvement that compliance with tightening silica standards demands.

Where Mobile Plant Generates Dust: Source by Source

Mobile crushing and screening: dust generation points and control challenges

The cumulative effect is that a mobile crushing and screening train with a feed hopper, primary crusher, secondary crusher, two screen decks and six conveyor transfers generates dust at eight to twelve discrete points along the processing train. Workers in the vicinity — the excavator operator feeding the hopper, the crusher attendant, the loader operator managing product stockpiles, and any workers downwind — are exposed to the combined output of all of these sources simultaneously.

The Regulatory Framework: Mobile Plant Is Not Exempt

The most important regulatory reality for mobile crushing and screening operators is that no exemption exists for mobile plant. The same workplace exposure standards, the same silica management obligations, and the same compliance enforcement apply to a mobile jaw crusher on a construction site as to a permanent processing plant at a tier-one mine.

Chapter 8A crystalline silica provisions (WHS Regulations, effective 1 September 2024) apply to all businesses processing crystalline silica substances — defined as materials containing at least 1% silica by weight. Mechanical crushing and screening of rock, aggregate, gravel, concrete, asphalt or any natural stone material is explicitly identified as a crystalline silica process. For operations assessed as high-risk crystalline silica work, a silica risk control plan is mandatory. Accredited crystalline silica training is required for workers.

NSW Resources Regulator has published a specific General Information Release on dust control for mobile crushing plant, and the May 2025 Technical Reference Guide on monitoring and control of worker exposure to airborne dust includes a dedicated section (3.2.9.4) on mobile crushing and screening. The NSW Regulator’s January–June 2026 compliance priorities include targeted assessment activities for tier 2 quarries focusing on fixed and mobile crushing and screening plants, with over 800 notices issued in the preceding 12-month programme.

Queensland RS20 states that the use of mobile crushing plants and screens on coal mines to crush and screen materials for road construction, sheeting of roads, ballast and other purposes shall give consideration to reducing the amount of airborne dust. QGL02 applies to all mineral mines and quarries using mobile processing plant.

Victoria’s OHS Regulations define the mechanical screening of crushed material containing crystalline silica and any quarrying process involving silica-bearing material as a crystalline silica process, triggering the full suite of hazard control statement, risk assessment and high-risk crystalline silica work obligations.

The practical consequence is that every contract crusher, every mobile screening operator, every quarry using portable plant, and every construction project operating a mobile processing train must comply with the same silica management framework as a permanent mine processing facility — but without the permanent infrastructure that fixed plants use to achieve compliance.

Why Water-Only Spray Systems Fall Short on Mobile Plant

Every modern mobile crusher and screen is equipped with a water spray system. Spray bars are fitted at the crusher inlet, across screen decks, at conveyor transfer points and, on some models, at the discharge conveyor. Water is supplied from an on-site tank or connected water supply via a pump and distribution manifold.

These spray systems suppress the larger dust particles effectively. Coarse particles are heavy enough to be wetted and knocked down by water droplets. The problem is the fine respirable fraction — the particles below 10 μm that penetrate deep into the lungs and cause silicosis, progressive massive fibrosis and lung cancer. These particles exhibit two properties that make them resistant to plain water suppression.

Hydrophobic surface behaviour. Freshly fractured rock surfaces expose mineral crystal faces that resist wetting. The finest silica particles have a surface energy that causes water droplets to bead around them rather than adhere. The particles literally deflect off the water droplet and remain airborne. Increasing water volume does not solve this problem — it increases water consumption and can create slurry handling issues without improving the capture of the respirable fraction.

Size mismatch. The effectiveness of a water spray depends on the spray droplet size being matched to the dust particle size. Standard spray nozzles on mobile plant produce droplets of 100–1,000 μm. Respirable silica particles are 0.1–10 μm. The probability of a 500 μm water droplet colliding with and capturing a 5 μm dust particle in a turbulent air stream is low. The physics of impaction, interception and diffusion that govern droplet-particle contact all favour larger dust particles and discriminate against the finest, most hazardous fraction.

The result is that water-only spray systems on mobile plant may achieve 30–60% reduction in total visible dust but significantly less reduction in the respirable fraction that drives occupational health outcomes. A mobile plant that appears adequately dust-controlled visually may still be generating respirable silica concentrations that exceed the 0.05 mg/m³ workplace exposure standard — and will certainly exceed the proposed 0.025 mg/m³ limit.

Chemical Activation: Making the Existing Spray System Work on the Respirable Fraction

GRT: Activate is engineered specifically for this problem. It is a liquid concentrate that is injected into the mobile plant’s existing water supply — the same tank, the same pump, the same spray bars. No new hardware, no modifications to the plant, no additional infrastructure. The product modifies the surface tension and ionic charge of the spray water so that the droplets actively attract and bind fine hydrophobic particles on contact.

The mechanism is fundamentally different from increasing water volume. Instead of relying on the random probability of a large water droplet colliding with a small dust particle, the activated water creates an electrostatic attraction between the droplet and the particle. Fine silica particles that would deflect off plain water are instead pulled onto the droplet surface and held. The capture efficiency for the respirable fraction — the fraction that causes disease — increases dramatically.

Independent testing has verified that GRT’s activation technology is 12 times more effective than water alone in suppressing fine dust. This is not a marginal improvement. It is a step-change in the performance of the spray system that is already installed on the plant. The same nozzles, the same water pressure, the same spray pattern — with 12 times the capture efficiency on the particles that matter most.

For mobile plant operators, the practical advantages are critical. Activate travels with the plant. When the crusher relocates to a new site, a new pit, or a new construction phase, the dosing arrangement moves with it. There is no fixed infrastructure to leave behind, no new system to commission at the new location. The operator fills the water tank, the concentrate is added at the specified ratio, and the spray system operates as normal — with activated water instead of plain water.

Complementary Controls: Beyond the Spray System

Chemical activation of the spray water is the most impactful single intervention for mobile plant dust control, but effective management requires complementary controls across the entire processing area.

Haul road and access road treatment. The roads serving the mobile plant — from the source face to the feed hopper and from the product stockpiles to the despatch point — generate dust from every vehicle movement. GRT: Haul-Loc dosed via SMART Dosing Units reduces road dust by 80–90%, protecting workers and preventing road-generated dust from compounding the processing dust burden.

Stockpile wind erosion control. Product and feed stockpiles around the mobile plant are exposed to wind erosion. GRT: Ore-Loc provides polymer veneering for product stockpiles, preventing wind erosion without affecting product quality. GRT: Enviro-Binder protects cleared areas and exposed batters surrounding the processing site.

Cabin filtration. Excavator operators feeding the hopper and loader operators managing stockpiles are enclosed in cabins that should provide a controlled-atmosphere environment. Cabin filtration systems must be maintained to the standard specified in the site’s dust management plan — HEPA or equivalent filtration, positive pressurisation of 25–50 Pa, regular inspection and filter replacement.

Operational positioning. Locating the mobile plant so that the prevailing wind direction carries dust away from, not towards, the operators and the site office is a zero-cost control that is frequently overlooked. Wind socks and real-time wind monitoring enable operational adjustment of positioning and production rates during high-wind events.

Practical Implementation: Getting Chemical Suppression Working on Your Mobile Plant

1. Assess your current spray system. Review the number, location and condition of spray nozzles on the crusher, screens and conveyor transfers. Replace any blocked or damaged nozzles. Ensure the pump delivers adequate pressure (typically 2–5 bar for dust suppression sprays). The activated water needs the same spray infrastructure that plain water uses — but it needs that infrastructure to be functioning correctly.
2. Add GRT: Activate to the water supply. The concentrate is dosed into the plant’s water tank at the specified ratio. Mixing is straightforward — the product disperses readily in water. For operations with multiple mobile plants, the dosing can be standardised across the fleet.
3. Monitor the result. Personal exposure monitoring on crusher attendants, excavator operators and loader operators provides the evidence that activated spray water is reducing respirable dust concentrations in the breathing zone. Compare results against the baseline established under plain-water operation. Real-time dust monitors positioned downwind of the processing area provide immediate feedback on the ambient dust reduction.
4. Document for compliance. Record the product used, the dosing rate, the spray system configuration and the monitoring results. This documentation demonstrates compliance with Chapter 8A obligations, responds to the NSW Regulator’s mobile crushing plant guidance, and provides the evidence base for the site’s silica risk control plan.
5. Relocate with confidence. When the plant moves, the dosing arrangement moves with it. Activate concentrate travels in standard IBCs. The same dosing protocol applies at every location. Consistency across sites and across operators is critical for sustained compliance.

Mobile Plant Deserves More Than a Water Spray and a Hope

Mobile crushing and screening plant generates some of the highest respirable silica concentrations on any site. The workers operating and attending this plant are among the most exposed. And the regulatory framework — Chapter 8A, RS20, QGL02, the NSW TRG, Victoria’s OHS Regulations — applies with full force to every mobile plant operation, regardless of size, sector or duration.

Water-only spray systems suppress the visible dust. They do not adequately suppress the respirable fraction that causes silicosis, progressive massive fibrosis and lung cancer. Chemical activation of the existing spray water with GRT: Activate — independently verified as 12 times more effective than water alone — targets the specific particle size range that drives health outcomes, using the spray infrastructure that is already installed on the plant.

For quarry operators, contract crushers, construction managers and mine processing managers responsible for mobile plant dust control, the path to compliance is practical, deployable and effective: activate the water, monitor the result, document the evidence, and relocate with the confidence that the same performance will follow the plant to its next location.

Sources and References

NSW Resources Regulator: General Information Release — Dust Control on Mobile Crushing Plant

NSW Resources Regulator: Technical Reference Guide: Monitoring and Control of Worker Exposure to Airborne Dust (May 2025) — Section 3.2.9.4 Mobile Crushing and Screening

NSW Resources Regulator: January–June 2026 Compliance Priorities — tier 2 quarry assessments, 800+ notices on fixed and mobile plant

Safe Work Australia: Stronger Regulation of Crystalline Silica Substances — Chapter 8A, 1 September 2024

Queensland Resources: Recognised Standard 20 — Dust Control in Surface Coal Mines, mobile crushing plant provisions

WorkSafe Victoria: Construction: Preventing Exposure to Crystalline Silica Dust — quarrying and crushing process obligations

Occupational Hygiene: Respirable Dust and Silica Monitoring for Mining and Quarrying Operations (March 2026)

WA DWER: Works Approval W6946/2024 — indicative dust suppression points for mobile crushing and screening

GRT: GRT: Activate — dust suppression for crushers, screens and transfer points

GRT: GRT: 12X — independently verified 12× more effective than water alone

GRT: Mine and Quarry Dust Legislation Changes in Australia — GRT product range by dust source

GRT: GRT: Haul-Loc

GRT: SMART Dosing Units

GRT: GRT: Enviro-Binder