Respirable Dust and Silica Monitoring for Mining and Quarrying Operations

Mining and quarrying are among the highest-risk industries for respirable crystalline silica (RCS) exposure in Australia. Whether you operate hard rock metalliferous mines, coal mines, or quarries, understanding your dust monitoring obligations and implementing robust compliance programs is essential—and legally required under the Work Health and Safety Act 2011 (Cth) and state-based mining legislation.

This guide explains what mining and quarrying operators must know about RCS and respirable dust monitoring, state-specific regulations, practical monitoring strategies, and when to engage an experienced occupational hygienist.

Why Mining and Quarrying Face the Highest Silica Risk

Australia’s geology is rich in quartz-bearing rock. When mining and quarrying operations extract, drill, load, and transport hard rock, they generate silica-laden dust at concentrations often far exceeding the Workplace Exposure Standard (WES).

Hard rock metalliferous mining (copper, lead, zinc, gold, iron ore) poses the greatest RCS risk, particularly in underground operations where ventilation is harder to control. Drilling, blasting, and mucking create high dust concentrations. The WES for RCS is 0.05 mg/m³ (as an 8-hour time-weighted average), effective from 1 September 2020—one of the lowest occupational exposure standards in Australia.

Quarrying (dimension stone, crushed rock, sand) involves mechanised extraction and processing, creating sustained respirable dust. Coal mining combines coal dust hazards with RCS exposure from roof and floor strata.

Open-cut vs underground operations differ significantly: underground mines have poorer natural ventilation and rely on engineered ventilation systems; open-cut sites benefit from natural wind but can expose workers to high point-source dust during blasting and loading.

Regulatory Framework for Mining Dust in Australia

National Legislation

The WHS Act (Cth) and model Work Health and Safety Regulations 2011 (Cth) apply nationwide. Employers must ensure, so far as reasonably practicable, the health and safety of workers—which includes eliminating or minimising exposure to respirable dust and silica.

The Safe Work Australia Model Code of Practice (November 2025) provides the primary national guidance on silica dust risk control, including assessment, monitoring, and health surveillance obligations.

State and Industry-Specific Regulations

Mining in Australia is regulated partly at state level, creating variations:

Queensland Coal Mines
– Coal Mining Safety and Health Regulations 2017 require compliance with Queensland’s Recognised Standard 14 for dust control.
– Coal dust and respirable dust monitoring is mandatory for coal mines.

Western Australia
– Mining is regulated under the Mines Safety and Inspection Act 1994 (WA).
– All mines (underground and open-cut) must maintain comprehensive dust monitoring records and report non-compliance.

New South Wales
– The Resources and Energy Major Projects Division provides sector guidance.
– Coal and metalliferous mines must comply with the WHS Regulations and follow recognised safety standards.

Victoria and South Australia
– Both states apply the WHS Regulations (Cth) framework.
– Mining operators should also reference state-based industry guidance.

Quarrying (All States)
– Quarrying is classified as a manufacturing/construction activity under the WHS Act.
– The Safe Work Australia Code of Practice for Silica Dust applies with equal force.

Who Must Monitor Dust in Mining and Quarrying?

Under the WHS Act and Safe Work Australia guidance:

Mine operators and site managers are the primary duty holder. You must ensure monitoring is conducted as part of your workplace assessment.
Coal mines (under Queensland and other state coal-specific regulations) must have nominated competent persons to oversee dust monitoring.
Quarrying operations must conduct monitoring if risk assessment identifies potential for RCS or respirable dust exposure above 50% of the WES.

Monitoring is not always outsourced: some large mines employ internal occupational hygienists. However, AIOH-certified occupational hygienists bring independent expertise, recognised qualifications, and defensibility in regulatory inspections.

Key Dust Hazards by Mine Type

Hard Rock Metalliferous Mines (Highest RCS Risk)

Drilling operations: Produce silica-laden aerosols, especially dry drilling. RCS concentrations often 10–100× the WES.
Blasting: Generates large dust clouds; underground, dust settles on all surfaces and is re-suspended during mucking.
Mucking (loading ore): Workers breathe high concentrations as rock fragments and dust are mechanically loaded.
Transport: Hauling and dumping ore generates resuspended dust.
Crushing and milling plants: On-site mineral processing creates fine dust in confined spaces.

Underground-specific hazards: Poor ventilation in remote working areas, dust accumulation on roof and walls (secondary exposure), reliance on personal protection if controls fail.

Coal Mines

Coal dust itself is a serious hazard (risk of pneumoconiosis), but seam coal often contains quartz inclusions, creating RCS exposure:

Longwall and continuous mining: High dust release during cutting.
Development headings: Driving new tunnels through quartz-rich seams or strata.
Roof fall management: Bolting and shotcreting roof strata can expose workers to respirable dust.

Coal mines typically have stricter statutory requirements (particularly in Queensland), including mandatory dust monitoring and health surveillance.

Quarrying Operations

Quarry type determines dust risk:

Dimension stone: Sawing and splitting creates fine silica dust; outdoor exposure partially mitigated by wind but concentrated near machinery.
Crushed rock: High-powered screening and crushing operations create sustained respirable dust; dust collection systems essential.
Sand extraction: Dry processing increases RCS if silica sand is crushed or screened; wet processing reduces dust generation significantly.

Monitoring Requirements Specific to Mining

Personal Dust Monitoring

Personal monitoring is the legal standard for demonstrating WES compliance. It involves:

A worker wearing a calibrated air sampling pump (typically 2.2 L/min) for silica sampling, or 2.0 L/min for respirable dust.
A cyclone sampling head positioned in the worker’s breathing zone (lapel or collar).
Collection onto a filter during a representative work shift (usually 8 hours).
Laboratory analysis using approved methods (see below).

Who to monitor:
– All workers in high-risk roles: drillers, loaders, muckers, blast supervisors, process plant operators, quarry machine operators, crushermen.
– At least annually for ongoing exposure; more frequently if roles change, controls are modified, or previous results approach the WES.
– Multiple workers in the same role (at least 2–3 per task per site, different shifts if applicable).

Approved Methods

For RCS analysis: All Australian-accredited laboratories must comply with AS 2985-2009 Code of Practice for Occupational Air Sampling. The reference method is gravimetric analysis of quartz content via X-ray diffraction (XRD) or infrared spectrometry. This method is slow (results in 7–14 days) but legally accepted.

For respirable dust: Same AS 2985 framework applies; results typically available in 5–7 days.

For coal dust: Queensland coal operations may reference AS 2985 or state-specific coal dust methods. Confirm with your regulator.

Frequency of Monitoring

Best practice and regulatory expectations:

Ongoing baseline: At least annual monitoring for all mines and quarries with identified RCS risk.
After control changes: If ventilation is upgraded, new machinery introduced, or work methods change, re-monitor within 3 months.
After regulatory concern: If regulator or AIOH consultant identifies risk, increase frequency immediately.
High-risk operations (underground hard rock, confined quarry processing): Many operators monitor quarterly or bi-annually for critical roles.

Static (Area) Monitoring in Mining

Static sampling (fixed air pumps at representative locations) is supplementary, not primary evidence for WES compliance, but it serves important functions:

Ventilation assessment: Helps identify whether general levels are controlled.
Source identification: Pinpoints high-dust zones needing engineering controls.
Real-time monitoring: Real-time optical dust monitors can alert operators to exceedances and guide immediate control adjustments.

For underground mining, static monitors at haul routes and working areas help optimise ventilation. For quarries, area monitors near processing plants assess general control effectiveness.

Personal vs Static Monitoring in Mining Environments

See our dedicated guide: Personal vs Static Dust Monitoring.

Key point for mining: Personal monitoring is mandatory for legal compliance. Static monitoring is a management tool supporting ventilation and source control optimisation.

Challenges of Underground Monitoring

Underground mining presents logistical and safety challenges:

Mobility: Workers are in moving vehicles or changing locations; maintaining a consistent 2+ hour sampling period can be difficult.
Equipment constraints: Pumps must be intrinsically safe (non-sparking); certain pump types are prohibited in gassy mines.
Dust stratification: Dust settles; re-suspension depends on traffic, ventilation, and work intensity. A sample at one location may not reflect worker exposure if they move frequently.
Sample integrity: Transporting filters through underground environments without contamination or damage requires careful protocols.

Solution: Experienced mining hygienists work with site ventilation engineers and safety officers to design representative sampling campaigns, often scheduling samples during shift changes or specific high-exposure operations.

Ventilation and Dilution: Primary Controls in Mining

The WHS Act hierarchy requires elimination as the first control, followed by substitution, engineering controls, administrative controls, and PPE as a last resort. For mining dust, the primary engineering control is ventilation.

Underground Mines

Modern underground mines employ:

Main ventilation circuits: Fresh air intake → working areas → return airways → exhaust. Designed to maintain negative pressure in high-dust zones and positive pressure in refuge areas.
Auxiliary ventilation: Flexible ducting directing air into working headings and dead-end areas.
Dilution ventilation rates: Typically 3–5 air changes per hour in underground operations, though this depends on workload and dust generation.

Ventilation design is critical: if it is inadequate, even low dust-generating machinery (e.g., electric drills) can create uncontrolled exposure.

Open-Cut Mines and Quarries

Natural wind: Primary source of dilution; exposure depends on wind direction and speed relative to work locations.
Haul road dust control: Water or dust suppressants applied to roads reduce re-suspension from vehicle traffic.
Mobile dust collection: Some quarries deploy mobile dust collectors near processing plants.
Blast timing: Scheduling blasts during high-wind periods and clearing the site to reduce post-blast exposure.

Assessment of Ventilation Adequacy

Ventilation alone is not enough: you must validate it is working. This involves:

Computational fluid dynamics (CFD) modelling for new underground mine designs.
Pitot tube or smoke tracer testing to measure airflow direction and velocity in working areas.
Regular inspection of ventilation ducting for damage, blockage, or disconnection.
Dust monitoring (personal and static) to confirm ventilation is controlling exposure below the WES.

If monitoring shows exposure above the WES, ventilation is insufficient, and immediate action is required: either increase airflow, relocate the worker, or implement additional controls (e.g., wet drilling, dust collection units).

When and How to Engage an Occupational Hygienist

Not all monitoring can be done in-house. Consider engaging a NATA-accredited occupational hygienist for:

Initial risk assessment: Professional identification of all high-risk roles, tasks, and locations. AIOH-certified consultants follow the Safe Work Australia Code of Practice.
Baseline monitoring campaign: Establishing scientifically sound sampling strategies that withstand regulatory scrutiny.
Interpretation of results: Understanding variation, uncertainty, and when controls need tightening.
Control validation: Recommending and validating engineering control changes.
Regulatory compliance review: Ensuring your monitoring program meets state-specific and national standards.
Health surveillance coordination: Advising on baseline health checks and ongoing health monitoring for workers with significant RCS exposure.

See our guide: How to Choose an Occupational Hygienist for Silica Monitoring.

Cost: Monitoring costs vary widely, but see Silica Dust Monitoring Cost Guide for typical pricing.

Record Keeping and Reporting in Mining

Retention Requirements

Exposure monitoring records must be retained for at least 30 years from the date of sampling. This applies to:

Personal sampling results (name, date, task, TWA result, laboratory details).
Static/area monitoring data.
Health surveillance results (baseline and periodic medical examinations).
Control modification and re-monitoring records.

Mining operators are advised to maintain electronic records with backup, as 30-year paper storage becomes impractical.

Reporting Obligations

Regulatory inspections: WHS inspectors, State Mining Regulators (NSW, QLD, WA, SA), and ASIC (for listed mining companies) may request records. Non-compliance or repeated exceedances are notifiable.
Notifiable incidents: If a worker develops silicosis or suspect silicosis, this may be notifiable under some state mining laws (e.g., Queensland).
Affected worker notification: If monitoring reveals exposure above the WES, the worker must be informed, and actions taken documented.

Practical Steps for Mine and Quarry Operators

1. Conduct a Dust Risk Assessment

Document all work areas, tasks, and worker groups. Identify where RCS or respirable dust exposure is likely to exceed 50% of the WES. Engage an occupational hygienist if in-house expertise is limited.

2. Establish a Baseline Monitoring Program

Sample 2–3 workers per high-risk role or task.
Ensure sampling represents typical working conditions.
Use a NATA-accredited laboratory.
Document sampling conditions: weather (for open-cut), ventilation status (for underground), equipment used.

3. Compare Results to the WES (0.05 mg/m³)

Below 0.025 mg/m³ (50% WES): Exposure well-controlled; continue annual monitoring.
0.025–0.05 mg/m³: Action zone; investigate controls, consider additional measures.
Above 0.05 mg/m³: Non-compliant; take immediate corrective action (see What to Do if Silica Exposure Exceeds the Limit).

4. Implement Engineering Controls First

Upgrade ventilation in underground mines.
Deploy wet drilling or dust suppression at the source.
Improve haul road design and dust control.
Install or improve dust collection on processing equipment.

5. Review and Re-monitor After Control Changes

After implementing new controls, re-monitor within 3 months to confirm effectiveness. If exposure remains above the WES, escalate to more stringent controls or additional administrative measures.

6. Communicate with Workers

Inform workers of monitoring results (without unnecessary alarm).
Explain control measures and their purpose.
Encourage reporting of dust sources or ventilation failures.
Maintain a safety culture where dust control is a shared responsibility.

7. Plan for Health Surveillance

Workers with significant RCS exposure should undergo baseline and periodic health checks (chest X-rays, spirometry). Coordinate with occupational medicine practitioners and maintain confidential records.

The Shift to WEL in December 2026

In December 2026, Australia’s Workplace Exposure Level (WEL) system transitions from the current WES framework. The RCS WEL is expected to remain at 0.05 mg/m³, but the mechanism for assessing compliance may change. Mining operators should:

Monitor Safe Work Australia guidance for WEL transition details.
Ensure your monitoring program is compatible with future WEL assessment protocols.
Engage your occupational hygienist early to understand transition implications for your site.

See: Silica WEL 2026: Employer Guide.

Frequently Asked Questions

Q: Is personal dust monitoring required for all mining and quarrying sites?

A: Personal monitoring is legally required if your risk assessment identifies potential for RCS or respirable dust exposure above 50% of the WES. For all hard rock mining and quarrying operations, this is virtually certain. Specific exemptions are rare and require documented justification.

Q: How long does it take to get dust monitoring results?

A: Gravimetric analysis (the standard method for RCS) typically takes 7–14 days from receipt at an accredited laboratory. Plan your monitoring campaign to allow for this lag; results inform corrective action decisions.

Q: Can we use real-time dust monitors instead of sending filters to a lab?

A: Real-time monitors (optical or gravimetric) provide immediate feedback and are excellent for ventilation management and source identification. However, they are not yet approved as the sole compliance evidence for WES. Combine real-time data with periodic lab-based gravimetric sampling to demonstrate compliance and control effectiveness.

Q: What is the difference between respirable dust and silica?

A: Respirable dust is all particles small enough to reach the lower respiratory tract; it includes silica but also minerals, coal dust, and other substances. Silica (quartz) is the toxic component of concern in mining. We measure RCS (respirable crystalline silica) specifically because it causes silicosis. The WES of 0.05 mg/m³ applies to RCS, not total respirable dust. For coal mines, both coal dust (respirable) and RCS are regulated.

Q: How often should underground mines monitor?

A: At minimum, annually for each high-risk role. Many operators monitor quarterly, particularly in deep underground hard rock mines where ventilation variability is high. After any ventilation upgrade or work method change, re-monitor within 3 months.

Q: What happens if a result exceeds the WES?

A: Exceeding the WES means the control strategy is inadequate. Immediate steps: (1) Inform affected workers, (2) Re-assess controls (ventilation, work method, PPE), (3) Implement corrective actions, (4) Re-monitor to confirm effectiveness. Continued non-compliance is a breach of the WHS Act and will attract regulatory attention.

Q: Do we need separate monitoring for coal dust and RCS in coal mines?

A: Coal mines should monitor both respirable coal dust (for pneumoconiosis risk) and RCS (quartz content of coal and strata). Some state regulations specify different exposure standards for each. Coordinate with your laboratory and regulator to confirm the analytical requirements for your jurisdiction.

Q: How do we maintain sample integrity when monitoring underground?

A: Use sealed filter cassettes, transport samples in sealed containers, ensure hygienists do not contaminate the sample during collection, and maintain a chain-of-custody form. NATA-accredited labs will specify their transport requirements.

Q: What training do site staff need to conduct dust monitoring?

A: Pump operators should understand proper pump calibration, filter handling, and safety (e.g., not operating sparking equipment in a gassy mine). However, formal sampling should be conducted or supervised by a competent occupational hygienist to ensure scientifically sound methodology and defensible results.

Conclusion

Silica dust monitoring in mining and quarrying is not optional—it is a legal obligation and a moral imperative to protect worker health. Understanding your regulatory obligations, implementing a robust monitoring program, interpreting results correctly, and investing in engineering controls form the foundation of compliance.

Anitech Group’s AIOH-certified occupational hygienists have extensive experience in mine and quarry dust monitoring programs across Australia. We understand state-specific regulations, the challenges of underground operations, and the practical realities of quarrying. Whether you need baseline monitoring, result interpretation, or control validation, we can help.

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FEATURE: 1200x630px. Overhead view of an underground mine heading with ventilation ducting and a worker in reflective gear sampling dust; warm underground lighting with visible dust particles.
BODY_1: 800x450px. Close-up of a personal air sampling pump worn on a worker’s belt with cyclone sampling head at lapel level. After heading: “Personal Dust Monitoring.”
BODY_2: 800x450px. Wide shot of a quarry processing plant with dust visible around screening/crushing equipment and haul road below. After heading: “Open-Cut Quarrying Hazards.”