Injuries occurring to heavy equipment workers were examined to identify causative and risk factors. Data were compiled by the Mine Safety and Health Administration (MSHA) on 13,764 cases of mining injury associated with heavy equipment operation occurring from 1978 to 1983. Analysis was restricted to bulldozers, front end loaders, graders, scraper loaders, off highway haulage trucks, and over highway haulage trucks. Variables analyzed included equipment and accident type, occupation, worker activity, source and nature of injury, and injured body part. A total of 209 deaths were identified. Over highway haulage trucks had the highest fatal injury ratio, with one fatality out of every 36 injuries occurring on this equipment. Road graders had a fatality ratio of 1:168. Of all fatalities, 54 percent occurred to personnel engaged in operating equipment; 35 percent of these fatalities occurred to personnel using equipment they did not normally operate. Bulldozer operators had nearly double the fatality risk of other operators. Falls from equipment and alighting or mounting equipment accounted for 25 percent of all injuries. The primary activity associated with such falls was equipment maintenance. Striking against a moving object accounted for 20.7 percent of all injuries, and most frequently occurred during equipment operation. Sprains and strains accounted for 29.1 percent of all injuries; the back, ankles, and knees contributed to 66 percent of all such injuries. Contusions accounted for 14.6 percent of all injuries, and fractures represented 13.1 percent.