471 



MANGANESE NODULES 



Manganese is used as an additive metal in the manufacture of steel 

 to reduce its brittleness. It seldom costs more than 5 cents per pound 

 and is, therefore, much cheaper than other additives that can perform 

 its functions. Steelmaking accounts for more than 95 per cent of manga- 

 nese consumption. Although the United States is the major world con- 

 sumer, world consumption is expected to rise with the development 

 of steel plants in the emerging nations. The United States consumes 

 approximately one-seventh of the world's ore, importing 99 per cent 

 of its needs (35 per cent or more manganese content), with domestic 

 stocks enough for about six months. Domestic supplies are inadequate, 

 and low-grade recoverable ores are too expensive to process. Using 

 the cheapest of the tested processes, and allowing for further techno- 

 logical progress, it would cost the United States about $1 extra per ton 

 of steel to turn either to domestic deposits or to slags for manganese. 62 



The extent of world manganese reserves is not known; however, 

 they are so large and high-grade that at the present rate of consumption 

 they can be considered virtually unlimited. This is the reason for the 

 assertion that submarine manganese nodules can be mined profitably 

 for their minor constituents, particularly copper, nickel, and cobalt. 



The average high-grade nodules contain 35 per cent manganese, 2.3 

 per cent copper, 1.9 per cent nickel, and 0.2 per cent cobalt (see Table 

 X). Brooks used the percentages 35, 2, 2, and 0.5, respectively. 53 One 

 ton of such nodules, he estimated, contains 700 pounds of manganese, 

 10 pounds of cobalt, 40 pounds of nickel, and 40 pounds of copper. The 

 average 1970 market prices of these components were: 54 manga- 

 nese, 2.5 cents per pound ; cobalt, $2.20 ; nickel, $1.30 ; and copper, 60 



TABLE X.— RESERVES OF METALS IN MANGANESE NODULES OF THE PACIFIC OCEAN 



1 All tonnages in metric units. 



1 Amount available in the noduhs divided by the consumption rate. 

 3 Calculated as the element in metric tons. I " 

 < Calculated as the element in metric tons. 



3 Calculated as the element in metric tons. (U.S. Bureau of Mines, Staff, 1956.) 



by th 

 .(U.S 



s Present reserves so large as to be essentially unlimited at present rates of consumption. 

 1 Including deposits of iron that are at present considered marginal. 



Source: From Mero, op. cit., page 278. 



52 David B. Brooks. "Low-Grade and Nonconventlonal Sources of Manganese." (Balti- 

 more, Johns Hopkins Press, 1966). 

 68 Ibid., page 103. 

 » Commodity Data Summaries (January 1971), pages 38, 42, 88, and 102. 



