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Presentation Transcript
• 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

[email protected]

or visit

www.docep.wa.gov.au/ResourcesSafety

### Toolbox presentation: Occupation noise in the WA mining industry

October 2007

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
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
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)
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
Standard for occupational noise
• For noise exposure — 85 dB(A) for 8 hours
• For peak noise level — 140 dB(lin)
Employee hearing loss by occupation group

Percentage of employees with hearing loss >5%

• Surface mining 19.2%
• Processing plants 16.0%
• Underground mining 15.5%
• Management 14.4%
Employee hearing loss

Average threshold shifts

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
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 10-12 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
Noise control can be complex

Engage employees in process

Use noise control consultants to help solve your problems if complex

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
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

Ear plugs

Properly fitted

Wrongly fitted

Ear muffs

Proper clamping force

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

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’

Noise posters available online or

as hardcopies (contact Resources Safety)