title: Effectiveness evaluation of existing noise controls in a deep shaft underground mine.
abstract: Noise exposures and hearing loss in the mining industry continue to be a major problem, despite advances in noise control technologies. This study evaluated the effectiveness of engineering, administrative, and personal noise controls using both traditional and in-ear dosimetry by job task, work shift, and five types of earplug. The noise exposures of 22 miners performing deep shaft-sinking tasks were evaluated during 56 rotating shifts in an underground mine. Miners were earplug-insertion trained, earplug fit-tested, and monitored utilizing traditional and in-ear dosimetry. The mean TWA8 noise exposure via traditional dosimetry was 90.1 ± 8.2 dBA, while the mean in-ear TWA8 was 79.6 ± 13.8 dBA. The latter was significantly lower (p < 0.05) than the Mine Safety and Health Administration (MSHA) personal exposure limit (PEL) of 90 dBA. Dosimetry mean TWA8 noise exposures for bench blowing (103.5 ± 0.9 dBA), jumbo drill operation (103.0 ± 0.8 dBA), and mucking tasks (99.6 ± 4.7 dBA) were significantly higher (p < 0.05) than other tasks. For bench blowing, cable pulling, grinding, and jumbo drill operation tasks, the mean in-ear TWA8 was greater than 85 dBA. Those working swing shift had a significantly higher (p < 0.001) mean TWA8 noise exposure (95.4 ± 7.3 dBA) than those working day shift. For percent difference between traditional vs. in-ear dosimetry, there was no significant difference among types of earplug used. Reflective of occupational hearing loss rate trends across the mining industry, this study found that, despite existing engineering and administrative controls, noise exposure levels exceeded regulatory limits, while the addition of personal hearing protection limited excessive exposures.
authors.affiliation: a Mining Safety and Health Program, Environmental and Occupational Health, Division of Community, Environment, and Policy, Mel & Enid Zuckerman College of Public Health, University of Arizona , Tucson , Arizona.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Lutz
authors.forename: Rustin J
authors.initials: RJ
authors.lastname: Reed
authors.forename: Dylan
authors.initials: D
authors.lastname: Turner
authors.forename: Sally R
authors.initials: SR
authors.lastname: Littau
authors.forename: Vivien
authors.initials: V
authors.lastname: Lee
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Hu
mesh_terms: D004430:Ear Protective Devices; D006317:Hearing Loss, Noise-Induced / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D008906:Mining; D009623:Noise, Occupational / Q000009:adverse effects / Q000517:prevention & control*; D009784:Occupational Diseases / Q000209:etiology / Q000517:prevention & control; D016273:Occupational Exposure / Q000032:analysis* / Q000517:prevention & control
keywords: mining; noise; noise controls; noise exposures; underground mining