Analysis on the personal noise exposure in an outdoor iron mine factory

Objective To comprehend the noise exposure level in such an outdoor iron mine factory.Methods The subjects were chosen from the main work-types in the factory;25 individual noise dosimeters were used to measure the noise exposure levels,at least one work-shift of each work-type in the factory were measured.Then,the equivalent continuous A sound level in 40 hours weekly working time(LAeq·40 h)and mean noise levels were calculated by using software SPSS13.0.Results The results showed that the average noise level in the iron mine factory was 88.8 dB(A),the noise in all the workshops was nonstationary noise except ore dressing operaing area.The highest noise exposure was in the milling workers of ore dressing operating area,which reached 92.8 dB(A);secondary,were the belt-conveyor workers in crushing workshop and the maintain workers in maintaining workshop,which were 89.2 dB(A)and 88.5 dB(A)respectively.The lowest exposure to noise was in the drivers of blasting,mining and transportation workshops,the mean exposure levels were lower than the national hygienic standard[85 dB(A)].Generally,comparing with the environmental noise measurement,the induvidual noise measurement seemed more accurate.Conclusions The results suggested that the noise exposure levels of workers in ore dressing,crushing and naintaining workshop exceeded national hygienic standard[85 dB(A)],therefore,the hearing protection measures should be taken in these workers.