Occupational hearing loss of the workmen of an open cast chromite mines

BACKGROUND The present work aimed at to describe hearing threshold based on audiometry data of the mine workers based on their age, work station and years of working of an open cast chromite mine in Odisha, India at high fence. MATERIALS AND METHODS A cross-sectional study of hearing threshold of the subjects of the chromite mine was carried out. Audiometric data of 500 subjects were taken from the hospital of the mines of Sukinda Valley, Jajpur, Odisha, India. The latest audiometry data available during the period 2002 to 2008 was used in the statistical analysis. RESULTS The age group 50-60 years is found to be the most influential age group suffering significant hearing loss on both the ears. Also, the Work Zone area is found to be most significant area affecting hearing loss on both the ears. However, the subjects having experience of 30-35 and 25-30 years have the most significant hearing loss on the left and right ears, respectively. CONCLUSION The hearing loss is found to be at 6 kHz, thus the working areas of the subjects working at work zone should be regularly rotated in less noisy areas to reduce the exposure duration. High frequency noise protective device should be advocated among all the subjects in general and HEMMs operators in particulars. Regular audiometry test of all the subjects should be performed to identify the hearing loss of the subjects occurring at 6 kHz. It is essential to perform periodic maintenance of all the HEMMs to keep all the vehicles in good condition those are generating noise at dominating frequency of 4 and 6 kHz.