Abstract
Coal mine roof falls can be categorized according to character, trend, or pattern of occurrence. These U.S. Bureau of Mines articles propose two principal categories--geology-related and stress-related failure--and a number of subcategories. Then, by reflecting the probable cause of failure, each subcategory can suggest an appropriate technique for reducing the incidence of failure. Depending on local conditions, these control techniques may include supplementary support, destresing, or reduction of mine air humidity.