Feedback on verification exercise for proposed leading practice of supplements to a mine Hearing Conservation Programme that include the use of OAEs, coaching of employees and custom-moulded Hearing Protection Devices 2 October 2013 1

Outline Background Methodology Advantages Findings Challenges & Refinements required Audiogram analysis Conclusion 2

Background MOSH Industry Team mandated MOSH Noise team to conduct verification exercises on proposed leading practices Glencore Mototolo proposed: Supplements to a mine Hearing Conservation Programme that includes the use of OAEs, coaching of employees and custom-moulded HPDs 3

Advantages identified-OAEs Early identification of hearing loss Detects inner ear damage before hearing loss is evident on an audiogram Measures in smaller units than audiogram Can be used to check effectiveness of HPDs Coaching of employees based on OAE measures Enhances employee knowledge and motivation to prevent hearing loss Increased link between the workplace and health Increased integration of the HCP

Advantages identified- HPDs Best practice = Risk-based medical examination (RBME) Personalised fitting of the HPDs Considers individual differences amongst ears Increased ownership of the use of HPDs Seal-fit test Increased chance that planned attenuation levels achieved Annual maintenance Check on the condition of the HPD Opportunity to counsel about the care of and use

Methodology Objectives Gather all the necessary information Examine the details and the effectiveness Identify the required refinements Establish the validity of leading practice in the industry

Methodology Verification exercise included Site visits to Glencore Mototolo Interviews with the key stakeholders Observing the processes and procedures Analysis of historical employee audiogram and OAE and coaching data Identify the required refinements Recommendations on refinements needed

Findings A commercial company provides supplements to the mine Hearing Conservation Programme. The programme uses a 4-leaf clover approach that is aimed at action in four different areas namely: Noise level measurement: personal noise levels of the employees are measured by the mine Occupational Hygiene department and must be integrated into the programme in order to facilitate the correct choice of attenuation levels on HPDs.

Findings HPDs: In the case of Mototolo custom-moulded HPDs are supplied by an affiliated supplier. The programme provides a personalized fitting of the HPD and a seal fit-test to ensure that the HPD seals in the employee’s ear. The filter in the custom-moulded HPD should be chosen based on the attenuation needed for the noise exposures of the employee to ensure that neither over-protection nor under-protection occurs. Coaching of the employee on the care of and the correct fitting of the HPDs is provided by the programme representative.

Findings Otoacoustic Emissions measurements (OAEs): At the same time as when the HPD is fitted, a test known as Otoacoustic Emissions (OAEs) is used to measure the functioning of the inner ear, the part of the ear where noise causes damage. Since OAEs can indicate a reduction in inner ear function before a hearing loss is identified on an audiogram, the OAE test method can be an early indicator of hearing loss.

Challenges - 1 Audiogram test results, Noise level measurements, HPD records, OAE test results and coaching records are not integrated in a way that facilitates an evaluation of the value added by each aspect of the programme i.e. no statistics available that indicates the programme is reducing NIHL or that the costs involved are adding value to the Hearing Conservation Programme at the mine. Establishing a link between all the available databases and developing reporting systems that will facilitate evaluation and proactive management of the HCP will address this challenge.

Challenges-2 Due to the lack of integration there is inefficiency and duplication of some processes: Duplication - counseling/coaching Inefficiency - lack of effective use of OAEs early identification of NIHL - Attenuation is not linked to the personal noise exposure level of the employee Integration of all aspects of HCP will address these challenges.

Challenges - 3 The quality control measures Documented and certified attenuation value Documented evidence of servicing procedure Documented evidence of seal-fit test Documented coaching content and procedures Documented outcome of coaching Quality control of some processes not adequate e.g. no tympanometry; attenuation of HPDs, calibration and maintenance documentation not available; time period between impression and fitting; seal-check outcome. Implementation of these quality control measures will address this challenge.

Challenges - 4 Best practice for HPD fitting requires that employees have a choice of HPDs in order to ensure fitting comfort and ownership of the HPD and compliance with wearing them. Some of Mototolo employees do not have custom-moulded HPDs – the procedures and policies for these need to be integrated into the system. The complaint processes and records of the complaints for use in quality control of the system are not documented. The alternative disposable HPDs that are available for employees that do not want or cannot wear custom-moulded HPDs for valid reasons is not well-defined and if improved will enhance the HPD management system.

Audiogram analysis-Average age at time of test

Audiogram analysis

Audiogram analysis

Audiogram analysis

Audiogram analysis

Audiogram analysis

Audiogram analysis

OAE analysis

OAE analysis

Coaching analysis

Coaching analysis

Audiogram analysis

Coaching analysis

Coaching analysis

Coaching analysis

Conclusion There is currently insufficient evidence to be able to evaluate if the proposed leading practice is indeed a leading practice for the industry. The audiogram stability is a good sign that it could be a leading practice. If the refinements are implemented and more data is available for evaluation these practices have great potential to become a leading practice for the industry.