CONTROL OF ORE TRANSFER STATION NOISE AT A MINING SITE

A large ore transfer station at a mining site in Western Australia caused a noise problem to a large nearby area. The noise was mostly from the impact of the falling ore on the chute of the transfer station, which was random and low frequency in nature. A noise measurement conducted at a residence about 2.5km away from the transfer station indicated that noise level, though dependent upon the wind directions, was about 38 dB(A), which is above the environmental noise limit assigned to the area at night. The impact noise inside the station was as high as 100 dB(A), very likely to cause the noise exposure level of workers working in and around the station to exceed the occupational daily noise exposure limit of 85 dB(A). The impact of the falling ore on the chute was so strong that the vibrations of the chute, as well as of the whole structure of the station, were measured at very high levels. The reduction of low-frequency structure-borne noise from the vibration was one of the major priorities in the noise control project. A noise control system involving various technologies of noise absorption, wave trapping, noise barrier, vibration isolation and reduction has been successfully installed. The noise level on the top floor of the station has been significantly reduced by more than 10 dB(A). The vibration-borne noise has been dramatically decreased, as the vibration levels on the noise panels are now over 10 dB lower. The noise radiated to the environment from the station has been significantly attenuated. At the locations from 3 m to 48 m away from the station, the noise levels have been reduced by about 7 - 12 dB(A). (1) Current address: WorkSafe WA, Government of Western Australia, 1260 Hay Street, West Perth, WA 6005