Workshop on the Establishment of a Geological Model of ...

As indicated by Figure 42, there is no correlation between nickel and cobalt concentrations on a global
scale for most of the CCZ. A positive relationship between nickel and cobalt anomalies may be detected in
the western‐central part between longitude 137 o W and 147 o W.
Figure 42: Nickel and Cobalt
As shown in the figure, there is, in general, the inverse correlation between copper and cobalt content
for most of the Zone, which in some places is less pronounced and sometimes (between longitude 138 o W and
142 o W) high copper values coincide with high cobalt values in nodules.
Nodule deposits
One of the most important geological parameters of polymetallic nodules is their ability to form
concentrations with high abundance and metal content, which can be considered as nodule deposits with
certain cut‐off grades, which may have potential for economic development in future.
For the purpose of locating such deposits in the reserved areas, the author, on a consultancy with the
Authority, undertook in 1997 the study of estimating the resource potential of the reserved areas. Such basic
criteria as nodule abundance and cumulative metal content of three metals ‐ nickel, copper and cobalt – was
used. A criterion based on nickel equivalent was not used, since the pioneer investors had applied a different
formula to calculate that value. Besides, owing to the slight variation in manganese content values over
different areas and low prices for manganese, that formula by itself will mostly represent values of content of
the three metals, namely, nickel, copper and cobalt.
The nodule resources that may be favourable for possible future first and second generation mining
operations were defined by us as those with nodule abundance of more than 5 kg/ m 2 and Ni+Cu+Co content
of more than 2 per cent (basic assumptions used in 1980s during the drafting of the United Nations
Convention on the Law of the Sea).
They were divided into four nodule grades:
Grade“A” Nodule deposits with abundance of more than 10 kg/ m 2 and Ni+Cu+Co metal
content of more than 2.5 per cent.
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