For the first time, scientists have drilled down several hundred metres from the Kermadec Seas, in the South Pacific Ocean, into the Brothers Volcano below.
Cornel de Ronde, a research geologist with GNS Science, says the volcano offers "an opportunity to see what's going in these active hydrothermal systems on the sea floor".
"Most of the world's volcanism - about 85 per cent - occurs on the sea floor, so it's out of sight, out of mind for most folks," Mr de Ronde said.
Mr de Ronde is one of four Kiwis on board the JOIDES Resolution research ship.
The international ocean discovery program, consisting of 23 different nationalities, has spent two months out at sea.
"We were very interested in what metals are transported within these volcanoes, what they are, where they are, and how they got there," he said.
The team discovered the volcano was full of copper - and even gold – with the colour of the rocks indicating the presence of different elements.
However, using large drill bits to bore into the rocky summit of the volcano at 1200 metres below sea level is proving to be quite the challenge for the team, with acidic and hot fluids just two of the many obstacles the team must face.
"The hardest thing of all was to start a hole because a lot of it was ashy-type material and that's very difficult to start a hole. But we drilled in casing, and we drilled down through the casing into the hard rock below."
While the findings must now be taken on-shore for testing, the mission has been hailed a technological triumph in extreme conditions.