[Application of four risk assessment methods to risk assessment of noise-induced hearing loss in metal mining enterprises].

Objective: To compare the application of four risk assessment methods in the noise-induced hearing loss risk assessment of metal mining enterprises.

Methods: Using typical sampling method, 27 metal mining enterprises were selected in Guangdong, Shandong and Liaoning Provinces. Enterprises basic information and noise exposure data of key positions were collected by using on-site hygiene investigation and noise detecting method. Occupational hazard risk index method, classification of occupational exposure to noise, guidelines for risk management of occupational noise hazard, the International Council on Mining and Mentals'(ICMM) risk rating table method were used to analyze the risk of noise-induced hearing loss in metal mining enterprises.

Results: The median individual noise exposure of metal mining positions was 83.0dB(A), and 36.5%(70/192) of the measured values exceeded 85 dB(A). The noise exposure levels of excavation workers(93.5 dB(A)), mill operators(90.4 dB(A)) and crusher operators(86.2 dB(A)) were higher relatively. Different mining method(underground and surface) had significant effects on noise exposure of workers(P<0.05), and the noise exceeding standard rate of underground mining was higher(42.4%). According to the result of four risk assessment method, The overall occupational health risk level of noise-induced hearing loss was medium(weighted score 1.98) by ICMM risk rating table method, while the overall occupational health risk level of noise-induced hearing loss was low by occupational hazard risk index method, classification of occupational exposure to noise and guidelines for risk management of occupational noise hazard(weighted score 1.98, 1.73 and 1.86, respectively). The risk of excavation workers and mill operators were the highest, the risk of crusher operators was high, and the risk of air compressor operators, Screening operators, control workers, maintenance workers and pump operators were low or very low. The consistency of four risk assessment method was moderate(W=0.300, P<0.001), The classification of occupational exposure to noise and the guidelines for risk management of occupational noise hazard showed that these two risk assessment method had strong consistencies(Kappa=0.789, P<0.001).

Conclusion: The overall occupational health risk level of noise-induced hearing loss in metal mining enterprises in three provinces was low, and the highest risk positions were excavation workers and mill operators in 2019-2021. The classification of occupational exposure to noise and the guidelines for risk management of occupational noise hazard might overestimate the noise hazard risk when workers were equipped personal protection well. ICMM risk rating table method can distinguish the risk levels of different positions effectively and identify the high-risk hearing loss position as early warning. Occupational hazard risk index method was comprehensive and practical.