TSX- and Aim-listed Nautilus Minerals’ exploration partner, Teck Cominco, has discovered four new high-grade sea-floor massive sulphide (SMS) systems on Nautilus’s prospecting licences in the exclusive economic zone of the Kingdom of Tonga.
Laboratory testing of 17 massive sulphide samples, across the four newly discovered SMS systems, has returned an average grade of 16,4 g/t gold, 8,2% copper, 12,3% zinc and 184 g/t silver.
“The results that Teck Cominco has achieved with its first offshore mineral exploration campaign on our [tenements] are outstanding,” says Nautilus CEO Stephen Rogers.
“This is the first time that commercial exploration has taken place in Tongan waters, and the prospectivity of this area has been clearly demonstrated.”
Rogers adds that the Tongan discoveries “deepen our prospect inventory as Nautilus focuses on the development of its Solwara 1 project in the territorial waters of Papua New Guinea”.
“These new discoveries reinforce that we have the technology, know-how and the right partners to rapidly find SMS systems. We look forward to progressing these discoveries to the next stage with Teck Cominco over the coming months,” notes Rogers.
Nautilus is the first company to commercially explore the ocean floor for gold and copper SMS deposits and, subject to timely permitting, aims to start gold and copper production at its Solwara 1 project in 2010.
Teck Cominco vice-president: exploration Fred Daley describes outlining the four new high-grade mineralised systems “as a fantastic result”.
He says it is even more noteworthy that these are grass roots discoveries.
“We started this campaign in December 2007 and, since then, we have completed a full exploration cycle involving regional evaluation, target generation and target testing.
“With Nautilus’s assistance, we conducted geochemical and geophysical surveys, some in collaboration with marine research organisations, generating the targets that culminated in these discoveries, using the remote operated vehicle (ROV).
The four newly discovered systems, which are up to 90 km apart, were found during only nine days of ROV surveying.”
The Maka SMS is located at a water depth of about 1 660 m, and lies on the crest of the North East Lau Spreading Centre.
Sulphide outcrops up to 4 m have been mapped, using video camera and sonar instruments from a ROV, protruding from a base of predominantly pillow basalts. The strike length is currently estimated at 130 m, with a width of 100 m.
The Tunu-Sosisi SMS comprises three subsystems at a water depth of about 1 635 m along a roughly linear zone, lying on a major structural zone cross-cutting the southern rim of the North East Lau Caldera.
The Pia SMS is located at a water depth of about 1 470 m, and in close proximity to a major structural zone that cross-cuts the northern rim of the North East Lau Caldera. The approximate length of the system is 200 m, with a width of 80 m.
The Niua SMS comprises two subsystems that lie about 1 300 m apart and within individual craterlike depressions.
The first system, Niua-2, is at a water depth of 900 m and has an estimated strike length of 230 m, and a width of 170 m. The second system, Niua-3, is at a water depth of 1 180 m, with an estimated strike length of 270 m, and a width of 250 m.
On December 20, 2007, Teck committed to spend $12-million to conduct and manage a ship-based exploration programme in 2008 in one or more of four designated areas in Papua New Guinea, Tonga and New Zealand.
Excluded from these areas are the Solwara 1 to 10 projects, a 17 500-km2 area in the territorial waters of Papua New Guinea, and exploration licences and applications in Tonga and Fiji applied for before October 20, 2006, which remain 100% owned by Nautilus.
Teck Cominco will not earn an equity interest in any tenements through its expenditure, but will have the right to select, by the end of 2008, various countries for a country earn-in.
The company will have the exclusive right – for a term of five years – to form joint ventures on tenements acquired by Nautilus in certain areas since October 20, 2006.
Teck Cominco can earn a 40% interest in these tenements in the Bismarck Sea, Papua New Guinea, Solomon Sea, Papua New Guinea, Fiji and Tonga projects, by spending $25-million in each selected area within two years of such election.