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Minerals Report - International Seabed Authority

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variations of the values are driven by the prices of the most important metal<br />

contained in each deposit.<br />

1600<br />

1400<br />

1200<br />

1000<br />

800<br />

600<br />

400<br />

$/t<br />

Sulfides (rich)<br />

Nodules<br />

Sulfides (mean)<br />

200<br />

Co-crusts<br />

0<br />

1960 1965 1970 1975 1980 1985 1990 1995 2000<br />

Figure 3. Value of a tonne of "in situ" ore for various deep-sea mineral deposits.<br />

Table 7 displays the weight of each metal in the appraisal of the ore values. They have<br />

been determined for their average value along the 39-years period, their maximum<br />

(1979 for nodules and Co-crusts, 1980 for sulphides) and their 1999 value.<br />

Nodules Cobalt crusts Sulphides (mean) Sulphides (rich)<br />

1979 Mean 1999 1979 Mean 1999 1980 Mean 1999 1980 Mean 1999<br />

Ni % 18.5 24.4 14.8 5.4 12.5 4.4<br />

Co % 30.1 15.6 29.3 94.3 86.8 95.3<br />

Mn % 45.7 52.5 50.2<br />

Cu % 5.7 7.5 5.7 0.3 0.7 0.3 20.0 28.0 20.7 24.1 31.9 23.2<br />

Zn % 23.4 43.1 51.1 23.3 40.6 47.3<br />

Pb % 4.2 4.7 3.6 1.5 1.6 1.2<br />

Ag % 38.9 16.0 15.0 17.7 6.9 6.3<br />

Au % 13.6 8.2 9.6 33.3 18.9 21.9<br />

Value $/t 926 544 308 1051 348 337 709 404 237 1360 819 489<br />

The less variable value is for polymetallic nodules. It is regularized by<br />

manganese that contributes 50% of the total value, followed by nickel, or<br />

cobalt when its price is high. It is also the most valuable, when excluding the<br />

rich sulphides. During the 1960-1999 period, the pick values were determined<br />

by the cobalt prices, except in 1989 when the boost in industrial activity<br />

INTERNATIONAL SEABED AUTHORITY 445

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