Legal perspectives on deep-sea mining: International Seabed Authority governance and closure gaps, with lessons from Australia

Authors: Ashby, A

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DOI https://doi.org/10.36487/ACG_repo/2615_158

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Ashby, A 2026, 'Legal perspectives on deep-sea mining: International Seabed Authority governance and closure gaps, with lessons from Australia', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-18, https://doi.org/10.36487/ACG_repo/2615_158

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Abstract:
Deep sea mining (DSM) operates under 2 distinct legal contexts: domestic law within national jurisdiction and United Nations Convention on the Law of the Sea (UNCLOS) Part XI with the International Seabed Authority (ISA) in areas beyond national jurisdiction (ABNJ). This review integrates international law, ISA Mining Code Phase 2 negotiations and emerging national approaches to identify areas of consensus, points of conflict and persistent governance gaps. Three developments in 2024–2026 intensify the governance challenge: more than 40 nations have called for a precautionary pause or moratorium; the International Court of Justice’s 2025 advisory opinion is expected to strengthen environmental obligations under international law, and US executive action under the Deep Seabed Hard Mineral Resources Act (DSHMRA) is accelerating domestic seabed licensing outside the ISA framework. In Australia, the Environment Protection Reform Act 2025 (Cth), the new National Environmental Protection Agency from 1 July 2026, and the seabed mining ban in New South Wales (NSW) demonstrate that domestic governance is evolving rapidly in ways directly relevant to future DSM sponsorship decisions. The synthesis finds that the current international regime cannot yet support exploitation with confidence. Key gaps include incomplete exploitation rules (environmental thresholds, liability, closure), contested ISA accountability and transparency, structurally fragmented enforcement at sea, and underdeveloped financial assurance and post-closure obligations. Australia’s comparatively mature terrestrial approaches to environmental assessment, compliance and mine closure offer transferable design lessons, but require significant adaptation to ABNJ conditions. Australia is therefore well placed to advocate for coherent, enforceable exploitation rules and practical compliance and closure mechanisms before DSM exploitation is authorised.

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