Despite two decades of regulation and best efforts by mining companies, noise-induced hearing loss (NIHL) continues to be recognised as one of the major occupational health risks in the South African mining industry. Studies have indicated that nearly three out of four South African mine workers are being overexposed to hazardous noise levels, says health and safety solutions provider HSE Solutions GM Stephen Burrow.
Despite these statistics, it is a false assumption to believe that noise induced hearing loss is simply the price one must pay for working in the mining industry, says Honeywell Safety Products director of hearing conservation Brad Witt.
Burrow notes that hearing conservation is attainable through the use of adequate hearing protection products such as earplugs and earmuffs – which Honeywell Safety Products provides through its southern African distributor HSE Solutions.
While a mining operation in many ways presents one of the most difficult challenges for hearing conservation, with loud heavy machinery in confined reverberant space, coupled with a need for critical communication among co-workers; several companies have successfully reduced the rates of hearing loss among their noise exposed workers by adopting best hearing conservation practices, says Witt.
These include offering a variety of hearing protectors, ensuring the protectors allow good communication, providing training in their use, and implementing fi t-testing to document good protection. “Because mine workers do not have the luxury of distancing themselves from the noise source, it becomes the responsibility of the employee to conserve the hearing of its noise-exposed workers by investing in noise conservation efforts.”
Accomplishments in hearing conservation come at a price – often an investment in better product, training and monitoring. But most employers believe their investments are well worth the effort and have returned manifold benefits, including reduced claims activity and rates of recordable hearing loss.
Tips to reduce workplace hearing loss Witt has identified several common denominators that are cited by employees in their hearing conservation efforts. “On the surface, some of these tips seem too simple to have a significant impact, yet each one of these strategies was mentioned multiple times as a key ingredient for reducing workplace hearing loss,” he notes.
Variety Ear canals come in different sizes and shapes, affecting both fit and protection levels, as well as comfort of an earplug. A mine site that offers only one size or style of earplug sabotages its own hearing conservation efforts as few workers will be adequately protected.
One of the real benefits of offering a variety of hearing protection sizes and styles is the fact that it can generally be accomplished with little or no increase in cost. Whether a worksite offers 1 000 earplugs of one style, or 250 earplugs of four different styles, the cost would be quite similar. But the bigger variety will go far in providing a better fit for more ears, and protecting significantly more of the workers.
Like a cork in a bottle, an earplug that is too large or too small will never achieve an acoustic seal; and just like shoes, earplugs come in different sizes, and there is no such thing as a “one-size-fits-all” earplug.
TIP: Offer a variety of hearing protectors to provide a better fi t for the workers.
What would be a recommended mix of sizes or styles to optimise the fi t of earplugs at a mine site? Results from thousands of fi t-tests conducted across several worksites shows that the following four earplug styles would be an optimal offering:
• Large foam earplug
• Smaller foam earplug
• Large reusable earplug
• Smaller reusable earplug
TIP: Look for hearing protectors designed with ‘uniform attenuation’ across frequencies, which makes them more communication friendly. Allow workers to select the protectors that provide adequate protection without sacrificing communication.
In a noisy mine filled with warning signals and moving equipment, the common excuse heard from workers for not wearing hearing protection is ‘I would rather lose my hearing than lose my life.’ But it is a myth to assume critical communication and hearing protection cannot co-exist.
If a mine worker feels the earplug is isolating him from co-workers and warning signals, he will avoid the earplugs or simply insert them halfway, providing minimal protection. Employers can effectively eliminate this major barrier to workplace protection by offering a selection of hearing protectors that still allow good communication.
Hearing protectors are now available that reduce the overprotection and communication interference found in conventional protectors.
Several earplugs and earmuffs have been designed to maximise communication through uniform attenuation, allowing wearers to hear important sounds(coworkers, warning signals, radio and communication systems, maintenance sounds from machinery) more naturally while still protecting from harmful noise levels.
Noise-exposed mine workers have few inherent incentives for protecting themselves from loud noise.
After all, unlike other injuries in the mine, NIHL causes no pain or visible trauma, leaves no visible bruises or scars, is unnoticeable in its earliest stages, and generally takes years to diagnose.
Instead, the motivation to protect hearing must focus on how using hearing protection today affects long-term health and well-being tomorrow.
Studies repeatedly show that for fitting hearing protection, the best training format is individual training. One-on-one training far exceeds group training in effectiveness of hearing protector fi t, even if just a one minute explanation of how to fit earplugs at the time of new hire orientation.
Workers who had any level of individual training in fitting earplugs have proven to be much better protected, and more likely to achieve the protection levels that are shown on the package. Any employer who provides earplugs with no training is laying the groundwork for NIHL on the job. Many hearing protector manufacturers can provide training tools to assist in this effort: how-to videos, posters, and training materials to ensure good fit.
TIP: Provide individual training in how to fit earplugs, perhaps at orientation or during the regular audiometric evaluations.
Fit-testing of hearing protection, now adopted by many mining companies as a best practice, provides the one-on-one training so critical to proper protection.
A short test can be administered in the field under headphones, using the worker’s own earplugs, to measure the protection levels of the earplug, just the way they were inserted by the worker. If protection levels are found to be inadequate (as they often are), the worker can be immediately trained in how to achieve a good fit, or a different size/style of earplug can be tried.
TIP: Provide fit-testing of hearing protection, first for new hire employees, and then as time allows, for other noise-exposed workers.
In addition to ensuring each worker is adequately protected, fit-testing provides to employers good documentation of protection. If a spurious claim for hearing loss is fi led, the employer who has administered fit-testing can show that a worker was properly fit with adequate protection, and properly trained in its use.