Mining Publication: Application of a Microphone Phased Array to Identify Noise Sources on a Horizontal Vibrating Screen
In coal preparation plants, workers are often exposed to sound levels exceeding 90 dB(A). Vibrating screens are viewed as a significant contributor to preparation plant noise. Reducing the sound levels generated by vibrating screens could reduce the noise exposures of preparation plant employees. The National Institute for Occupational Safety and Health (NIOSH) measured the sound power level generated by a horizontal vibrating screen with the screen either directly on the floor or on rubber isolation pads. The sound power level was 100.6 dB(A) with the screen directly on the floor. With the screen placed on isolation pads, the sound power level was 100.6 dB(A) without the belt guard rattling and 108.3 dB(A) with the belt guard rattling. The 160 Hz to 800 Hz frequency range was dominant when the belt guard was not rattling whereas the 1 to 10 kHz frequency range was most significant when the belt guard was rattling. A microphone phased array was used to examine noise sources on the screen. The belt guard, eccentric mechanisms, and steel coil springs were found to be significant noise sources. This paper provides detailed information on the findings of the research.