Abandoned mined-land (aml) fires occur in abandoned mines, in waste banks, and in unmined outcrops. Aml fires occur in every coal- producing state and present a serious health, safety, and environmental hazard. The emission of toxic fumes, subsidence, and the deterioration of air quality create an unsafe and unpleasant atmosphere that can depress property values for affected land and for adjacent areas. Between 1949 and 1972 the federal mining agencies were involved in 75 fire control projects in the eastern bituminous region, 21 projects to control 15 fires in the anthracite region, and 158 fire control projects in the western United States. The 1989 aml inventory listed 225 surface fires and 99 underground fires, affecting an estimated 7,000 acres. The cost of controlling these fires is estimated to exceed $780 million. Factors affecting the occurrence, propagation, and extinguishment of aml fires include the geology, the extent of previous mining, the rank of the coal, and the type and condition of adjacent strata. Conventional fire control methods include excavation, sealing, and excavated or flushed barriers. The probable effectiveness of these methods is less than 70 pct. Current research on improving standard methods and on developing new technology may significantly increase the effectiveness of aml fire control. Recent improvements in aml fire control include the U.S. Bureau of Mines mine fire diagnostic methodology to locate and monitor remote fires and the burnout control method of fuel removal.