Redesign of Continuous Miner Scrubber Fan System Ductwork for Noise Reduction

In the mining industry, Noise Induced Hearing Loss (NIHL) affects 90% of miners by age 50. Continuous Miners (CMs) are some of the loudest machines and reducing the noise would significantly reduce NIHL. To achieve noise reduction the project addressed the main noise source on the CM, the coal dust scrubber system. The goal was to identify and mitigate the dominant noise sources while maintaining the required dust collection performance. The ductwork leading to the fan was found to create significant inflow distortions ingested by the fan which increased noise. Multiple inflow distortion mitigation schemes were evaluated to reduce the noise source, such as: reshaping the area between the ductwork exit and fan inlet to give better rectangular to round transition, the demister mid span damper was removed, among other changes. Comparisons of noise predictions for the baseline and redesigned ductwork yield reductions of over 8 dB when combined with a previous rotor and stator redesign. A physical prototype that integrates the redesigned components is currently being manufactured and will be tested this year.