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Please read this before using presentation. This presentation is based on content presented at the 2007 Mines Safety Roadshow held in October 2007
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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: ResourcesSafety@docep.wa.gov.au 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% • Metal trades 18.6% • Processing plants 16.0% • Underground mining 15.5% • Management 14.4% • Electrical trades 10.6%
Relationship between noise exposureand hearing loss Hearing loss between 5 and 9%
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 Worn-out head band
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’
Use this guideline as a reference on recommended ways to control noise in mines
Noise posters available online or as hardcopies (contact Resources Safety)