A race for almost legendary deposits of gold and copper in waters around New Zealand and nearby Pacific states has heated up with a big find off Tonga.
Nautilus Minerals told the Toronto Stock Exchange and the London Stock Exchange's Alternative Investment Market (Aim) that it had discovered four new high-grade seafloor massive sulphide (SMS) systems in Tonga.
High grades of gold, copper, zinc and silver were present in the finds.
Nautilus has pioneered undersea mining in Papua New Guinea and has exploration rights in New Zealand's exclusive economic zone running up to Tonga and Fiji.
This year, rival Neptune Minerals said it had applied to begin a $622 million gold and copper deep-sea mining operation 300km north of East Cape.
On preliminary data publicly available, the new Tonga find is richer than the New Zealand mining.
The newly discovered SMS systems are 90km apart, near Niuatoputapu, in northern Tonga. They are in waters 900 metres deep in contrast to the New Zealand finds which are 1200 metres to 1300 metres deep.
Nautilus chief executive Stephen Rogers said the find in Tonga was outstanding. It was the first time that commercial exploration had taken place in Tongan waters, he said.