Introduction
The Clarion-Clipperton Zone and Cook Islands Exclusive Economic Zone (EEZ) both contain polymetallic nodules that appear superficially similar.
However, there are subtle and important difference between these deposits, particularly around the metal composition of the nodules, and consequent processing opportunities as well as project economics.
Nodule Composition
The approximate average constinuency of nodules in each area is typically:
| Metal Ore |
Clarion-Clipperton Zone |
Cook Islands EEZ |
| Manganese: |
27% |
17% |
| Iron: |
7% |
16% |
| Nickel: |
1.3% |
0.4% |
| Copper: |
1.1% |
0.1% |
| Cobalt: |
0.22% |
0.4% |
| Molybdenum: |
0.065% |
0.03% |
| Total Rare Earth Elements: |
0.1% |
0.17% |
Visually it's clear that there are subtle but striking differences in this composition:
Relative Value
The various metal ores contained in the polymetallic nodules have vastly different values, and whilst processing costs and recoverability may vary singificantly, we can nonetheless crudely indicate the relative value of each using current commodity prices:
|
Clarion-Clipperton Zone |
Cook Islands EEZ |
| Metal Ore |
Refined $ / ton |
Composition |
Value |
Composition |
Value |
| Manganese: |
$2,060 |
27% |
$556 |
17% |
$350 |
| Iron: |
$105 |
7% |
$7 |
16% |
$17 |
| Nickel: |
$22,135 |
1.3% |
$288 |
0.4% |
$89 |
| Copper: |
$8,240 |
1.1% |
$91 |
0.1% |
$8.2 |
| Cobalt: |
$33,000 |
0.22% |
$73 |
0.4% |
$132 |
Using the refined metal price as a crude relative proxy for value, we can see a stark difference in value:
Caveats
Whilst this analysis gives a rough indication of the relative value of nodules in the CCZ versus the Cook Islands EEZ, it is nonetheless relatively simplistic. It makes the following simplfying assumptions:
- Ore values are all proportional to their refined metal values
- Refined metal weights are proportional to the weights of the metal oxides and sulphides present in the nodules
- Recovery rates of refined metal are all approximately equal across the various metals
- Ore processing costs are all the same per ton of refined metal
Furthermore, there are larger complexities and differences that need to be taken into account between the two regions:
- Nodule Density: Nodule density may vary, which massively impacts production costs
- Production Difference: Different depths mean that collector efficiencies and costs will vary
- Remoteness: Different distances from ports mean that transport costs are different
- Processing: Nodule compositions are sufficiently different that different refining methods may be required
- Commercial Terms: Different concession rates and profit-sharing arrangements lead to different levels of profitabilit
Summary
Whilst the Clarion-Clipperton Zone and the Cook Islands EEZ superficially contain similar polymetallic nodule deposits, their compositions are nonetheless quite different. When we apply simplistic assumptions about the relative value of the constituent ores, we see that the CCZ nodules are almost twice as valuable per ton recovered than their Cook Islands EEZ equivalent.
However, this analysis makes some significant simplifications. Furthermore, if we want to completely understand the relative differences between these areas, then we need to also consider broader factors, such as nodule density, remoteness of the location, and commercial terms.
In short, there are likely significant differences between the CCZ and Cook Islands EEZ, but these are not immediately clear or obvious.