occupational hygiene monitoring of dust

1. Small Mines Roadshow
October – December 2020
Occupational Hygiene
Monitoring of Dust

2. Occupational Hygiene Monitoring of Dust
Presentation Outline:
• Types of dust in small mines & quarries
• Requirement to monitor dust
• How is monitoring conducted?
• What analysis is done on samples?
• What do the results mean?
• Free Dust Sampling Program – status

3. Occupational Hygiene Monitoring of Dust
Atmospheric Dust
The two main types of atmospheric dust are:
 Inhalable Dust – dust particles that are inhaled and are trapped in the nose and throat region
 Respirable Dust – very fine dust particles that are inhaled and find their way deep into the lungs.
What is Silica Dust?
Silica – is a mineral present in most rocks, sand, gravel, clay and shale.
 When rocks materials are mechanically crushed, drilled, split or
screened fine particles of crystalline silica, or quartz, is released as
dust.
Respirable Crystalline Silica – is very fine silica dust particles that can
find their way deep into the lungs.
 Breathing in crystalline silica dust over a long period of time can
lead to lung cancer and silicosis.
Silicosis – is an irreversible scarring and stiffening of the lung tissue.

4. Occupational Hygiene Monitoring of Dust
Why do we need to monitor dust?
Under the Work Health & Safety Act:
 A Person Conducting a Business or Undertaking has a duty of
care to ensure people in the workplace are not exposed to health
and safety risks.
What monitoring is required?
Under the Work Health & Safety (Mines and Petroleum Sites)
Regulations:
 Monitoring of the health hazards associated with the mining
operation is required.
 Monitoring of the exposure of workers to the health hazards is
required.

5. There are two main types of dust monitoring:
 Personal Exposure Monitoring –
 sample is collected from the breathing zone of the worker.
 the worker wears the monitoring device while working (full shift).
 results are directly comparable to the Workplace Exposure Standard’s (WES’s).
 Static or Area Monitoring -
 monitoring in a fixed location (not worn by worker)
 monitoring duration can be short (15 minutes) or full shift
 results are NOT directly comparable to the Workplace Exposure Standards.
 results used to determine if dust is an issue in a certain area, or
 to determine if dust control measures are effective.
There are also two main ways of measuring dust:
 Active Sampling – a measured volume of air is drawn onto a filter using a
small sampling pump.
 Real Time Monitoring – air passes through a light beam or laser and the
number and size of particles are measured in real time.
Occupational Hygiene Monitoring of Dust

6. Personal Monitoring
Occupational Hygiene Monitoring of Dust
Respirable Dust &
Crystalline Silica Sampling
(AS 2985-2009)
Cyclone Sampler – to only collect the
finer fraction of dust (<4µm)
Inhalable Dust
Sampling
(AS 3640-2009)
IOM Samper – to collect
all dust size fractions
Personal
Sampling
Pump
Filter Cassettes & Filters
Samples should be collected over the full work shift, or for as long as reasonably possible.
Transport clip
Grit Pot

7. Occupational Hygiene Monitoring of Dust
How do we analyse the samples?
 Sample filters are weighed before and after sampling.
 The amount of dust on the filter is determined by the change in weight
(gravimetric analysis).
 The filter can then be further analysed to determine dust composition
(eg. for metals, crystalline silica).
Samples should be analysed by an accredited laboratory.
Inhalable Dust Filter
Respirable Dust Filters

8. Occupational Hygiene Monitoring of Dust
Aim: Personal Exposure Sampling Results <50% of the Workplace Exposure Standard.
What do the results mean?
 Details recorded during sampling (flow rate, sampling time, shift length etc) are used to determine a dust result expressed as
concentration in air (mg/m3).
 The result is then directly comparable to Workplace Exposure Standards – if a PERSONAL sample was collected.
 A Workplace Exposure Standard is the airborne concentration of a chemical that is not expected to cause an effect on the
health of an exposed worker. They are calculated to account for workplace exposures over an 8-hour work day, 40-hours per
week, over a working lifetime.
 Each WES is expressed as an 8-hour Time Weighted Average (TWA)
concentration.
 The 8-hour TWA WES can be adjusted to allow for extended work shifts (eg 10hr,
12hr shifts) and different work rosters.
 Current WES’s for dust are:
Inhalable Dust 10mg/m3 8hr TWA
Respirable Dust 3mg/m3 8hr TWA
Respirable Crystalline Silica 0.05mg/m3 8hr TWA
Result <50%
of WES
Result >50%
of WES
Result ≥100%
of WES
Report
Exceedance to
Regulator
Investigate &
Implement
Controls
Maintain
Effective
Controls

9. Occupational Hygiene Monitoring of Dust
Resource Regulators’ Sampling & Monitoring Assistance Program:
Personal dust sampling was offered to Operators of small mines and quarries to assess
potential high exposure activities or areas at their sites.
Program Progress Status:
• Offer extended to 572 small mines / quarries
• A total of 19 sites responded and requested monitoring
• Sampling completed at 9 sites to date
• A further 10 sites scheduled for sampling prior to end December 2020
• 35 respirable dust and crystalline silica samples collected to date

10. Occupational Hygiene Monitoring of Dust
2020 Small Mines Roadshow