#1298 1982 · UN Third Conference on the Law of the Sea / International Seabed Authority · International law / deep-sea mining
The UN made mining firms cut each seabed claim in half and picked which half was theirs
the problem
Only wealthy nations could survey the seabed, and the UN had no way to verify a company's claimed site value
background
As the 1970s deep-sea mining rush loomed, negotiators drafting the UN Convention on the Law of the Sea faced a structural problem: only a few wealthy states and their companies had the ships and technology to survey the ocean floor for valuable polymetallic nodule deposits, while the treaty's own International Seabed Authority was designed to hold the seabed's mineral wealth in trust for all countries, including ones with no capacity to survey anything themselves. Simply requiring companies to report a site's value honestly invited an obvious problem — a surveying firm had every incentive to claim its find was mediocre, keep the richest ground for itself, and hand over marginal territory the Authority could never independently verify.
The Authority could not solve this by fielding its own survey fleet to check every claim; that defeated the purpose of relying on private capital to do the expensive exploration work at all. It needed a mechanism where the company's own self-interest, not an inspector's judgment, would force it to value the two halves of its claim honestly.
what everyone would do
The straightforward fixes were to have the Authority independently value every claimed site before approving it, which meant funding a survey capability that defeated the entire point of relying on private capital, or to simply trust the applicant's self-reported valuation, which invited every applicant to undervalue the portion it planned to keep for itself.
what they saw
The Authority need not verify a valuation if it chooses last. Split the claim into two halves the applicant swears are equal; the Authority picks either — bias just hands the better half away.
the move
Annex III, Article 8 requires any applicant to survey an area large enough for two commercial mining operations, then submit data dividing it into two parts it certifies are of equal estimated commercial value. The Authority — acting for the Enterprise and developing states — then simply picks which of the two halves to reserve for itself; the applicant keeps the other. Because the Authority chooses last, an applicant that skews the split to keep the richer half only guarantees the Authority takes that richer half instead.
why it works
The mechanism relocates the incentive to cheat onto the party with no way to benefit from cheating: the applicant sets the boundary, but the Authority decides which side of it becomes whose, so a company that shades the division in its own favor only increases the odds the Authority takes the good half and leaves the company with the bad one it built. No independent appraisal, auditor or geological survey by the Authority is required — the applicant's own self-interest does the honesty-enforcing.
the payoff
Investors from France, Japan, the USSR, India, China and Korea submitted paired sites under the rule, banking claims for developing states.
where it breaks
It only works when a single division genuinely can be split into two comparably valuable, physically separable halves, which is straightforward for a homogeneous mineral field but breaks down for resources where value is concentrated in one indivisible location, or where the divider can hide information about the site the chooser cannot detect at all — a company that lies about total site value, rather than the split between two known halves, defeats the mechanism entirely.
what came after
The banked-site, divide-and-choose mechanism remains the operative rule for every deep-sea mining exploration contract today and stands as one of the few working examples of split-and-choose fairness enforced at full treaty scale.
references
- [1]United Nations Convention on the Law of the Sea, Annex III, Article 8 (Reservation of Areas)United Nations, 1982un.org
- [2]The International Seabed Authority and Deep Seabed MiningUN Chronicle, United Nations, 2018un.org