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| A dust collector fan with noise treatments installed |
Background
NIOSH is working with the Pennsylvania State University and Joy Mining Machinery to develop engineering noise controls to reduce noise generated by continuous mining machines. The research involves the development of noise treatments for a dust collector fan, which is a vane axial fan located inside the continuous mining machine. The noise treatments applied to the fan were:
- moving the turning vanes downstream,
- changing the shape of the leading edges of the turning vanes from straight and radial,
- extending the perforations and outside adsorptive layer to cover the entire fan housing,
- adding an extension with an absorptive layer on the onside to the fan discharge, and
- replacing the rotor with unevenly spaced blades with a rotor with evenly spaced blades
The effort resulted in an overall A-weighted sound power level reduction of 5 dB with only a 4 % reduction in the volume flow velocity through the dust collector. This research compliments the work performed on coated flight bars and the jacketed tail roller on continuous mining machine conveying systems.
Potential Outcome
The engineering noise controls developed as a result of this research, along with the prior research on the continuous miner's conveying systems (coated flight bars and jacketed tail roller), could lead to an overall noise reduction of up to 10 to 12 dB(A) at the operator position of the continuous mining machine. With these controls properly installed, it could be anticipated that 90% of the operators of continuous mining machines noise exposure will fall below MSHA’s permissible exposure limit. To raise industry awareness of the engineering noise controls developed through this work, research results will be published in trade magazine articles and presented at industry briefings concerning noise exposure in the mining industry. The effects of the engineering controls are expected to begin in 2006, when underground test results are finalized and published.