Minerals Report - International Seabed Authority
Minerals Report - International Seabed Authority Minerals Report - International Seabed Authority
grow on substrate rocks because of metal precipitation from cold ambient seawater close to the oxygen minimum zone 2 . Relative to ferromanganese nodules, the crusts contain elevated concentrations of cobalt (up to more than 2.0 wt. per cent) and Platinum (up to 3 ppm). Research on cobalt-bearing ferromanganese crusts has largely been carried out in the 1980s by the United States, Germany and Japan 2 . It was found that economic grade crusts should be at least 4 cm thick and contain >one wt. per cent cobalt on average 11 . The majority of the crust fields are found in the Exclusive Economic Zones of Micronesia, Marshall Islands, Kiribati, and the USA, as well as in the international waters of the Central Pacific Mountains. Mining of crusts fields involves the efficient fragmentation and in situ separation of the crusts from the substrate rock to avoid dilution of the crusts metal grade, a problem which has still not been sufficiently resolved (Table 5). However, hydro jet systems and heavy-duty roller combined with suction and hydraulic pipe lift or airlift devices have been designed but not yet fully tested. Any mining system needs to be capable of mining at least 1 million tonnes per year. This scenario allows for 80 % separation efficiency and 25% dilution by substrate rock fragments 2 . As the interest in ferromanganese crusts mining is currently, relatively low, new technical developments of mining equipment such as advanced trench cutters have not taken place. This is also true for metallurgical processing which needs to focus on the efficient recovery not only of the cobalt but also of the platinum, which has been a major problem in the past. Table 5: Mining Ferromanganese Crusts Efficient separation of crust from substrate rock by hydro jet system heavy-duty rollers Both systems need further development and full testing 7. Conclusions First order technical requirements for polymetallic massive sulphides exploration include portable drilling and coring devices to be operated from ships-of-opportunity. These systems need to be capable of drilling several INTERNATIONAL SEABED AUTHORITY 314
tens of meters into the seafloor with more than 50 per cent core recovery. For mining massive sulphides at and just below the seafloor, continuous operating devices with large-scale cutter heads in combination with airlift or hydraulic pumps need to be developed (Table 6). Exploration tools for cobaltbearing ferromanganese crusts such as deep-towed cameras, side-scan sonar, and TV-guided grabs are available. The problem of the efficient separation of the crusts from the substrate rock by suitable mining tools (hydro jet, rollers) has not been resolved and needs further consideration. Table 6: Continuous Mining of Seafloor Massive Sulphides Deposits - Rotating cutter heads (7-10 m diameter) - Airlift or hydraulic pumping of ore slurry to mining vessel - Transfer of ore from mining vessel to cargo freighter REFERENCES 1. J. Francheteau, H.D. Needham, P. Choukroune, T. Juteau, M. Seguret, R.D. Ballard, P.J. Fox, W. Normark, A. Carranza, D. Cordoba, J. Guerrero, C. Rangin, H. Bougault, P. Cambon, and R. Hekinian (1979), Massive deep-sea sulphide ore deposits discovered on the East Pacific Rise. Nature, 277, 523-528. 2. J.R. Hein, A. Koschinsky, M. Bau, F.T. Manheim, J. -K. Kang, and L. Roberts (2000) Cobalt-rich ferromanganese crusts in the Pacific. In: Handbook of Marine Mineral Deposits, D.S. Cronan (ed): 239-279. 3. S. Sarata and K. Matsumoto (1999), Deep-sea core boring BMS in Northern Mariana Area. Proceedings of the 3 rd ISOPE, Goa, India: 49-54. 4. P.M. Herzig, S.E. Humphris, D.J. Miller, and R.A. Zierenberg, R.A. (eds.) (1998), Proceedings of the Ocean Drilling Program, Scientific Results, Volume 158: Collage Station, TX. INTERNATIONAL SEABED AUTHORITY 315
- Page 272 and 273: een recovered is 25 cm. He also sai
- Page 274 and 275: shallower than 1500 metres, a shall
- Page 276 and 277: In relation to mining technology, o
- Page 278 and 279: On the most promising sites for cru
- Page 280 and 281: In addition to the International Se
- Page 282 and 283: 1. Introduction Plant life is impos
- Page 284 and 285: Table 1 Potential microbial metabol
- Page 286 and 287: Figure 2 Simplified representation
- Page 288 and 289: Figure 3 Major components of a gene
- Page 290 and 291: the mussel's nutrition. When experi
- Page 292 and 293: Reasons for this do not appear to b
- Page 294 and 295: egions, one study pointed out that
- Page 296 and 297: very widespread, supporting microbi
- Page 298 and 299: Studies of the rapid colonisation o
- Page 300 and 301: y mining, which is expected to be v
- Page 302 and 303: 2. J. B. Corliss, J. Dymond, L. Gor
- Page 304 and 305: 19. V. Tunnicliffe, A.G. McArthur a
- Page 306 and 307: SUMMARY OF THE PRESENTATION AND DIS
- Page 308 and 309: together with mucus that is secrete
- Page 310 and 311: close to neutral ph conditions, it
- Page 312 and 313: France, Germany, the United Kingdom
- Page 314 and 315: of the sedimentary column, whereas
- Page 316 and 317: Table 2: Research Submersibles and
- Page 318 and 319: 4. Technical Requirements For resea
- Page 320 and 321: 5. Processing Technologies The phys
- Page 324 and 325: 5. M.D. Hannington, A.G. Galley, P.
- Page 326 and 327: Dr. Herzig informed participants th
- Page 328 and 329: search for sites of hydrothermal ve
- Page 330 and 331: with such a grab. In addition to th
- Page 332 and 333: Remotely operated vehicles (ROVs) D
- Page 334 and 335: equired to make sure that the ship
- Page 336 and 337: Dr. Herzig summarized the technical
- Page 338 and 339: commercial. Since confidentiality o
- Page 340 and 341: CHAPTER 8 FACTORS IN FINANCING EXPL
- Page 342 and 343: The traditional project stages that
- Page 344 and 345: there is a subset that forms in spe
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- Page 348 and 349: 7. Why SMS Mines will be Lower Cost
- Page 350 and 351: 8. Modelling SMS mining offers scop
- Page 352 and 353: Because exhalative SMS deposits are
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- Page 356 and 357: flow to the metal markets. He also
- Page 358 and 359: shortage in the next couple of year
- Page 360 and 361: starts, the operation could take pl
- Page 362 and 363: Based on this and other considerati
- Page 364 and 365: Mr. Malnic said that the mining ope
- Page 366 and 367: and silver. Except for volcanically
- Page 368 and 369: 2.2. Major Features of the Draft Of
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grow on substrate rocks because of metal precipitation from cold ambient<br />
seawater close to the oxygen minimum zone 2 . Relative to ferromanganese<br />
nodules, the crusts contain elevated concentrations of cobalt (up to more than<br />
2.0 wt. per cent) and Platinum (up to 3 ppm). Research on cobalt-bearing<br />
ferromanganese crusts has largely been carried out in the 1980s by the United<br />
States, Germany and Japan 2 . It was found that economic grade crusts should<br />
be at least 4 cm thick and contain >one wt. per cent cobalt on average 11 . The<br />
majority of the crust fields are found in the Exclusive Economic Zones of<br />
Micronesia, Marshall Islands, Kiribati, and the USA, as well as in the<br />
international waters of the Central Pacific Mountains.<br />
Mining of crusts fields involves the efficient fragmentation and in situ<br />
separation of the crusts from the substrate rock to avoid dilution of the crusts<br />
metal grade, a problem which has still not been sufficiently resolved (Table 5).<br />
However, hydro jet systems and heavy-duty roller combined with suction and<br />
hydraulic pipe lift or airlift devices have been designed but not yet fully<br />
tested. Any mining system needs to be capable of mining at least 1 million<br />
tonnes per year. This scenario allows for 80 % separation efficiency and 25%<br />
dilution by substrate rock fragments 2 . As the interest in ferromanganese<br />
crusts mining is currently, relatively low, new technical developments of<br />
mining equipment such as advanced trench cutters have not taken place. This<br />
is also true for metallurgical processing which needs to focus on the efficient<br />
recovery not only of the cobalt but also of the platinum, which has been a<br />
major problem in the past.<br />
Table 5: Mining Ferromanganese Crusts<br />
Efficient separation of crust from substrate rock by hydro jet system heavy-duty<br />
rollers<br />
Both systems need further development and full testing<br />
7. Conclusions<br />
First order technical requirements for polymetallic massive sulphides<br />
exploration include portable drilling and coring devices to be operated from<br />
ships-of-opportunity. These systems need to be capable of drilling several<br />
INTERNATIONAL SEABED AUTHORITY 314
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