Passive noise and dust control for coal mine longwall shearer

摘要

The U.S. mining industry struggles with hazardous noise and dust exposures in underground mining. Specifically, longwall coal mine shearer operators are routinely exposed to noise levels at 151 percent of the allowable daily dose, and approximately 20 percent exceed regulatory dust levels. The current study aims to mount a partial barrier on the full-scale mock shearer at the National Institute for Occupational Safety and Health Pittsburg Research Laboratory. The hypothesis is that separating the operator from the cutting drum will reduce noise and dust levels experienced by the operator. As an initial step, the investigators performed modeling experiments in a similarly sized sound lab at Wright Patterson Air Force Base. Recorded underground coal mine shearer operation noise was played back through a sound system to model the partial barrier. Readings were taken with and without the barrier in place and compared to the predictive model. The partial barrier produced an average insertion loss of 12 A-weighted decibels (dB(A)). The model accurately predicted the insertion loss in one set of tests to 1.2 dB(A), but differed by 4.6 dB(A) in a second test set, possibly due to inaccurate absorption coefficients for the model or over-prediction in the low frequency range.