The Bureau of Mines estimated the potential availability of iron ore from 129 domestic and foreign mines and deposits in 25 market economy countries. The availability of four products on a total and regional basis was determined from demonstrated resources of 75.3 billion lt. From the resources evaluated there are a total of 18.6 billion lt of sinter fines, 4.9 billion lt of lump ore, 14.7 billion lt of pellets, and 820 million long tons (mmlt) of pellet feed potentially available at a 15-pct discounted-cash-flow rate of return (dcfror), f.O.B. Port. On a regional basis, at or below a total cost of $0.26 Per iron unit there are 1.7 billion lt, 2.8 billion lt, and 186 mmlt of sinter fines potentially available from Brazil, Australia, and Africa, respectively. There are 825 mmlt of lump ore from Brazil and 1.4 billion lt from Australia potentially available at or below a total cost of $0.24 Per iron unit. There are 2.1 billion lt of pellets potentially available from the United States at or below a total cost of $0.80 Per iron unit, while 442 mmlt are potentially available in Brazil at or below $0.38 Per iron unit. South America has 208 mmlt of pellet feed potentially available at or below a total cost of $0.28 Per iron unit. While the resources of iron ore are more than adequate to satisfy demand, the future of the iron ore industry is very dependent upon changes in the world economy, and on the domestic scene, changes in the domestic steel industry and steel imports.