Small underground coal mines have historically experienced higher fatality rates than larger mines (National Academy of Sciences, 1983; Peters and Fotta, 1994). By "small", we mean mines that have fewer than 50 underground employees. Although various ideas have been presented about what factors might be responsible for this difference, researchers have had a difficult time establishing the specific causes. Mine size is highly correlated with seam height. Smaller mines tend to operate in significantly thinner coal seams than large mines. Mining height is usually equal to the height of the coal seam, and can vary from as low as 20 inches to a height of 12 feet or more. Because there are several reasons to expect that differences in mining height are related to differences in injury rates for particular types of accidents, additional statistical analyses have been performed to examine this issue (see Fotta and Mallett, 1997). Of the 90 million hours worked by underground miners at bituminous coal mines in 1996, approximately half were worked in mines with an average seam height of five feet or less. Additionally, 94% of mines operating in seams of 3.5 feet or less employed fewer than 50 people. Thin seam or low coal mines are located almost exclusively within the Appalachian coal fields. And, in fact, 96% of small thin seam mining operations are located in three states: Kentucky, West Virginia, and Virginia . The proportion of total U.S. underground bituminous coal being produced from thin seam mines appears to have remained constant during recent years. However, as thick seams of underground coal are depleted, one might expect to eventually see a decline in the average height of the U.S. coal seams being mined. The objective of this article is to continue to identify and quantify the kinds of injuries associated with working in thin seam mining operations. An analysis of these injuries may help us to identify the hazards associated with working in low-seam conditions that place miners at greater risk of injury than their counterparts who work in high-seam conditions.
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