production of 1.5 minion tons, 75 round trips each of 18 days' duration will be required. Allowing for 

 regular drydocking, this schedule could be maintained with four barges and their respective tugs. 



—Onshore reduction plant. It has been shown experimentally that a hot sulphuric acid leaching process 

 might be economic for the extraction of contained metals in manganese nodules, where the lime content 

 is low. Percentage extraction is about 90 per cent for the cobalt, nickel and copper in the form of 

 sulphides, and about 50 per cent for the manganese as manganese oxide. Further reduction and refining 

 may be carried out without significant loss of metal content using standard metallurgical processes. Total 

 cost of the process including refining is estimated tentatively at $20 per ton. 



Table 5 



COST SUMMARY 



CAPITAL AND OPERATING COSTS 



Unpublished MMTC source. 



2 



Unpublished industry source. 



Maritime Reporter and Engineering News, 1967, June 1 , p. 36, Aug. 15, p. 6. 



Unpublished Bureau of Mines source. 



VII- 184 



