To date, ISA has issued 17 exploration permits and another seven are in the works. A spokesman told the BBC there has been an unprecedented surge in interest from both private and state-owned companies.

ISA also said that deep sea mining is on the threshold of a new era. It is in the process of deciding how to handle the licencing for actual mining as well as how to share the proceeds, a portion of which are to go to developing countries.

Previous testing by companies has shown large numbers of small rocks on the ocean’s floor that are rich in gold, copper, nickel, cobalt and rare earths.

An assessment of the Clarion-Clipperton zone in the Pacific Ocean suggests more than 27 billion tonnes of rocks could be lying on its floor, including 290 million tonnes of copper and 340 million tonnes of nickel.

Related: Britain plunges into deep sea mining with American company

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