It was not too long ago that coal and ore from underground mines were shoveled or manually loaded onto carts drawn by horse or mule (Snaders and Peay, 1988). As recently as the mid-1950s, almost a third of all coal produced in the U.S. was still hand-loaded. In the years prior to the introduction of mechanization, mining was truly backbreaking work. The principal tools of the miner were the pick and shovel, powered solely by raw muscle. Figure 106.1 illustrates a common task of the undergound miner of this period: undercutting a coal face in perparation for blasting. As shown in Figure 106.1, this task was performed while the miner was lying on his side, using a pick to hew the coal and a shovel to support the body. Miners could spend three to six hours undercutting a coal face, using their picks to make a one meter deep horizontal incision at the base of the mineral seam. Advances in mechanization in the second half of the 20th century have greatly reduced physical demands on the mine worker. Even so, mining remains among the most physically demanding occupations. While the overall magnitude of physical work performed by the miner has been reduced, many unique physical and environmental demands remain. For example, miners may have to deal with restricted workspace, less than desirable illumination, muddy or wet floor conditions, high levels of whole-body vibration, and considerable heavy lifting. Of the stressors listed above, the most demanding environmental characteristic of underground mines is undoubtedly the limited vertical workspace in which many miners must function. The impact of this single factor on human-centered design is extraordinary. The significant injury experience in the mining industry is undoubtedly the consequence of the muliplicity of risk factors present in this environment.
Mine-workers; Mine-shafts; Miners; Mining-industry; Coal-miners; Coal-mining; Coal-workers; Ergonomics; Human-factors-engineering; Musculoskeletal-system; Musculoskeletal-system-disorders; Muscular-disorders; Muscle-tension; Muscle-stress; Demographic-characteristics; Anthropometry; Posture; Biomechanical-modeling; Biomechanics; Physical-stress; Stress; Heat-stress; Vibration-exposure; Vibration-control