1. 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

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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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.

9. 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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. Audiogram analysis-Average age at time of test

17. Audiogram analysis

18. Audiogram analysis

19. Audiogram analysis

20. Audiogram analysis

21. Audiogram analysis

22. Audiogram analysis

23. OAE analysis

24. OAE analysis

25. Coaching analysis

26. Coaching analysis

27. Audiogram analysis

28. Coaching analysis

29. Coaching analysis

30. Coaching analysis

31. 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.