1. Please read this before using presentation
Mines Safety Roadshow Toolbox presentation
Please read this before using presentation
This presentation is based on content presented at the 2007 Mines Safety Roadshow held in October 2007
It is made available for non-commercial use (eg toolbox meetings) subject to the condition that the PowerPoint file is not altered without permission from Resources Safety
Supporting resources, such as brochures and posters, are available from Resources Safety
For resources, information or clarification, please contact:
or visit

2. Toolbox presentation: Occupation noise in the WA mining industry
Mines Safety Roadshow Toolbox presentation
Toolbox presentation: Occupation noise in the WA mining industry
October 2007

3. Mines Safety Roadshow 2007 - Toolbox presentation
Noise legislation
Mines Safety and Inspection Act 1994 — Section 9
Mines Safety and Inspection Regulations 1995 — Part 7 Division 1
Approved Procedures — Regulations 7.6 and 7.10
Relevant legislation
Act and regulations available from State Law Publishers at

4. Apply to over 300 mines operating in WA Cover more than 56,500 miners
Background
Apply to over 300 mines operating in WA
Cover more than 56,500 miners
Majority of miners work 12-hour shifts
Over 74% of miners are overexposed to noise

5. Basic rules of working with noise
The noise levels are described in decibels (dB)
They can not be added or subtracted in the usual arithmetic way because the dB scale is logarithmic
Two identical tools emitting noise of 90 dB(A) produce the combined noise level of 93 dB(A), not 180 dB(A)

6. Basic rules of working with noise cont.
A 3 dB(A) increase corresponds to a doubling of sound energy
A 10 dB(A) increase corresponds to a 10 times increase of the sound energy
A 20 dB(A) increase corresponds to a 100 times increase of the sound energy

7. Typical noise levels at operator’s ear level
Mines Safety Roadshow Toolbox presentation
Typical noise levels at operator’s ear level
Noise source
Noise range dB(A)
Haulage truck
80-89
Dozer
82-85
Excavator
81-86
Jumbo drill
Impact wrench
97-103
Angle grinder
92-106
Airleg drill
WA data provided to Resources Safety

8. Standard for occupational noise
For noise exposure — 85 dB(A) for 8 hours
For peak noise level — 140 dB(lin)

9. Average noise exposure in WA mining industry
Mines Safety Roadshow Toolbox presentation
Average noise exposure in WA mining industry
Average noise exposure
Time to reach exposure standard if not protected
Surface miners
94 db(A)
1.0 hour
Underground miners
101 dB(A)
12 minutes
All miners
96 dB(A)
38 minutes
WA data provided to Resources Safety

10. Employee hearing loss by occupation group
Mines Safety Roadshow Toolbox presentation
Employee hearing loss by occupation group
Percentage of employees with hearing loss >5%
Surface mining 19.2%
Metal trades 18.6%
Processing plants 16.0%
Underground mining 15.5%
Management 14.4%
Electrical trades 10.6%
WA data provided to Resources Safety

11. Relationship between noise exposure and hearing loss
Mines Safety Roadshow Toolbox presentation
Relationship between noise exposure and hearing loss
Hearing loss between 5 and 9%
WA data provided to Resources Safety

12. Mines Safety Roadshow 2007 - Toolbox presentation
Employee hearing loss
Average threshold shifts
WA data provided to Resources Safety

13. Steps aiming to control noise at work
Assess risks to develop a noise control plan
Reduce risks for all employees
Investigate and implement good practice for control of noise
Prioritise noise control measures
Use hearing protection for residual risks
Carry out a noise dosimetry program to check the effectiveness of noise control measures

14. Some simple noise control techniques
Application of damping material to chutes, hoppers, machine guards etc., can give a 5-25 dB reduction in the noise radiated
Cabin internal noise can be reduced by dB by applying damping pads and sound barrier mats to floor and engine bulkhead
Reduce fan speed by 30% to achieve a noise reduction of 8 dB

15. Noise control can be complex
Engage employees in process
Use noise control consultants to help solve your problems if complex

16. Selected for protection, user preference and work activity
Hearing protectors
Selected for protection, user preference and work activity
Guard against over-protection — isolation can lead to under-use and safety risks
Require information, instruction, training, supervision and motivation
Will only protect if worn all the time and properly

17. Rating hearing protectors
The sound level conversion (SLC80 ) rating of a hearing protector, ear plugs or headset is a simple number and class rating that is derived from a test procedure as outlined in the Australian/New Zealand Standard AS/NZS 1270:2002

18. Class and specification of hearing protectors
SLC80
Class
May be used up to this noise exposure level
10 to 13 1
90 dB(A)
14 to 17 2
95 dB(A)
18 to 21 3
100 dB(A)
22 to 25 4
105 dB(A)
26 or greater 5
110 dB(A)

19. Mines Safety Roadshow 2007 - Toolbox presentation
Ear plugs
Properly fitted
Wrongly fitted
Ensure people are properly trained in the correct fitting of ear plugs
People’s ears are different. Is there sufficient variety of ear plugs provided to suit different ear canals and different job requirements? One size (and type) may not fit all, and comfort and effectiveness are important considerations to ensure compliance.

20. Mines Safety Roadshow 2007 - Toolbox presentation
Ear muffs
Proper clamping force
Worn-out head band
Ear muffs left in the “up position” on hard hats may also lose their clamping force and the pads become compressed

21. Mines Safety Roadshow 2007 - Toolbox presentation
Reduction in protection provided by hearing protectors with decreased wearing time
Example: Effectiveness of wearing an ear muff with a rating of 30 dB for an exposure time of one hour
Wear time
Effective attenuation
60 minutes
30 dB
55 minutes
11 dB
50 minutes
8 dB
45 minutes
6 dB
Sound attenuation = The reduction in the intensity or in the sound pressure level of sound which is transmitted from one point to another
Effective attenuation = how well do the protectors do their job?
If worn correctly for the full one hour then the attenuation (or decrease in sound energy) is 30 dB, as per the rating.
But if taken off for a total of 5 minutes in that hour (e.g. to listen to someone speaking, rub ear), the effective attenuation is actually 11 dB and not 30 dB (remembering that the scale is logarithmic and 20 dB is 100 times the sound energy)!

22. Noise assessment as the end point Reliance on hearing protection
Our challenge
Away from …
Noise assessment as the end point
Reliance on hearing protection
Towards …
Control of noise risks through prioritised action plans
Introducing equipment with good noise and vibration characteristics – ‘Buy Quiet’

23. Mines Safety Roadshow 2007 - Toolbox presentation
Use this guideline as a reference on recommended ways to control noise in mines
Available from Resources Safety website or contact to get hardcopy

24. Mines Safety Roadshow 2007 - Toolbox presentation
Noise posters available online or
as hardcopies (contact Resources Safety)