Mining Publication: Less Sound Underground: Reducing Roof Bolting Machine Drilling Noise

National Institute for Occupational Safety and Health (NIOSH) researchers strive to reduce noise-induced hearing loss for coal miners. The highest occurrence of hazardous noise exposure in the United States is within the mining industry, where 24% of miners have a reported hearing loss as a result. To find out the causes, NIOSH reviewed surveillance data from the Department of Labor Mine Safety and Health Administration (MSHA) on noise exposure in the mining industry. This study revealed which machine operators exceed 100% noise dose per the MSHA Permissible Exposure Level (PEL) - the noise limit a mine worker can be exposed to for their shift. To reduce noise overexposure for miners, researchers have developed noise controls that reduce the sound at the operator's position. For one machine in particular, a roof bolting machine (RBM), NIOSH partnered with Corry Rubber Corporation and Kennametal, Inc. to develop a suite of noise controls. This article presents the most significant findings from that research. A detailed report on the noise control suite is listed in the reference section. The control suite reduces sound levels at the operator’s ear by over 77%. This is significant because an RBM operator is the second-most likely of all underground coal mining equipment operators to be overexposed to noise.