This week, WA’s Department of Mines Industry Regulation and Safety (DMIRS) issued Mines Safety Bulletin no. 169 focused on the dangers of noise-induced hearing loss (NIHL) in mines.

Exposure to prolonged or excessive noise has been proven to cause permanent hearing loss and tinnitus (a high-pitched ringing in the ears). Both conditions are debilitating with serious impacts on the health and quality of life of affected persons and their families.

The MSIR require engineering controls to be implemented if a person is likely to be exposed to noise levels (without the effects of hearing protection devices (HPD)) above 85dB(A) or peak noise above 140dB(lin). If it can be demonstrated that engineering controls are not practicable, then exposure times must be reduced.

Data collected by the Department clearly shows that the use of ear plugs or hearing protection devices (HPD) is often not a reliable control due to incorrect fitting, or failure to use the devices when in a high noise area.

Noise Survey

A noise survey report and noise control plan are requirements of the Mines Safety and Inspection Regulations 1995 (MSIR). Persons at risk of NIHL and high noise emitting equipment are identified in the site’s noise survey.

While most mining operations have noise control programs in place, the primary focus for preventing noise-induced hearing loss (NIHL) is usually to provide hearing protective devices (HPD) rather than reducing noise emissions by higher-level controls such as substituting equipment for a quieter version or installing an engineered noise enclosure.

If these controls are still not adequate, further controls in the form of mandatory instruction and training, signage, and the supply and maintenance of hearing protective devices is required.

The DMIRS safety bulletin on managing noise said that an employer is required to verify that the controls are effective in preventing exposure to the hazard.

Audiometric testing

The Workers’ Compensation and Injury Management Act 1981  requires employers to conduct baseline hearing tests for all workers who are likely to receive a personal (8-hour equivalent) dose exceeding 90dB(A).

Employers are encouraged to conduct regular audiometric testing as a way of demonstrating the effectiveness of implemented noise controls. It also allows for intervention at early signs of hearing loss. Workers who have had a baseline hearing test may request in writing to their employer, subsequent hearing tests. This is testing is to be done at the employers expense and can only be requested annually by workers.

These requirements fall under MSIR r 3.27 which requires employers to conduct health monitoring if a workplace exposure (eg: noise) may cause an adverse health effect (eg: NIHL).

A range of other issues are also associated with exposure to excessive noise, including stress, high blood pressure, poor concentration, productivity loss, communication difficulties and cardiovascular disease.

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