Under the agreement, the PNG government paid Nautilus $7 million, which entitles it to a 15% stake in the project, with an option to increase it by another 15% in the next 12 months.

In October, an arbitrator ruled in favour of the Toronto-based company in a dispute with PNG over the ownership of the project, set to become the first commercial deep-sea mining in the world, after a nearly two-year battle.

Aside from the dispute, Solwara has been affected by weak gold and copper prices, but CEO Mike Johnson has repeatedly said that has not yet risked the commercial viability of the endeavour.

The Solwara 1 mine—originally slated to begin production by the end of 2013— is located in the Bismark Sea, north of Papua New Guinea.