To determine the availability of manganese for metallurgical purposes from selected world resources, the b.O.M. Evaluated the potential production of contained manganese in concentrates based on the demonstrated resources of 23 foreign and 8 domestic mines and deposits in 9 market economy countries. All but 2 of the 23 foreign deposits are operating mines; none of the domestic deposits are in operation. The demonstrated resources of the mines and deposits used in this study represent an in situ ore resource of approximately 2.2 billion tons, containing 780 million tons of manganese with a total recoverable production potential of 514 million tons of contained manganese in concentrates. The analyses of mines and deposits in this study indicate that about 213 million tons of the contained manganese (41 pct) is potentially available at a January 1981 constant dollar long-run total cost of up to $1.50 Per long ton unit (22.4 Lb, or 10.15 Kg contained mn), and 491 million tons (95 pct) is available at less that $3.30. The remaining 23 million tons, which is potentially available at much higher cost (about $8 to $35 per unit), represents the U.S. Deposits. On an annual basis, with a cost range of up to $1.75 Per long ton unit, the availability from currently operating mines would last at least 80 years based on 1980 world production data. Total manganese production costs are estimated to comprise mining--8 pct, beneficiation--3 pct, transportation--26 pct, and smelting--63 pct.