Key points
- Laboratory testing of 17 massive sulphide samples across the four systems averaged 16.4 g/t gold, 8.2% copper, 12.3% zinc and 184 g/t silver.
- The four systems, named Maka, Tunu-Sosisi, Pia and Niua, are up to 90 kilometres apart and were found during nine days of ROV surveying using the DEA surveyor.
- Teck Cominco began the exploration campaign in December 2007 and conducted the work in collaboration with CSIRO, ANU, NOAA and the Hawaii Institute of Geophysics and Planetology.
- On Dec. 20, 2007, Teck committed to spend $12 million (U.S.) on a 2008 ship-based exploration program across designated areas in PNG, Tonga and New Zealand, excluding the Solwara 1 to 10 projects.
Nautilus Minerals Inc. has been advised by its exploration partner, Teck Cominco Ltd., that it has discovered four new high-grade seafloor 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, returned an average grade of 16.4 grams per tonne (g/t) gold, 8.2 per cent copper, 12.3 per cent zinc and 184 g/t silver.
Stephen Rogers, Nautilus’s chief executive officer, commented: “The results that Teck Cominco has achieved with its first offshore mineral exploration campaign on our ground are outstanding. This is the first time that commercial exploration has taken place in Tongan waters and the prospectivity of this area has been clearly demonstrated. Building on our recent successes in Papua New Guinea (PNG), we now look forward to the commencement of our own program in Tongan waters when our vessel Nor Sky arrives later this week. These discoveries deepen our prospect inventory as Nautilus focuses on the development of its Solwara 1 project in the territorial waters of PNG. 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.”
Fred Daley, Teck Cominco’s vice-president of exploration, commented: “To outline four new high-grade mineralized systems is a fantastic result. It is even more noteworthy that these are grassroot 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 organizations, generating the targets that culminated in these discoveries, using the DEA surveyor remote-operated vehicle (ROV). The four newly discovered systems, which are up to 90 kilometres apart, were found during only nine days of ROV surveying.”
ASSAY RESULTS
Prospect Sample No. Au (g/t) Cu (%) Zn (%) Ag (g/t)
MAKA NEL1002 8.46 10.6 8.39 109
MAKA NEL1003 4.69 1.66 7.28 53
MAKA NEL1004 0.76 3.81 2.44 25
TUNU-SOSISI NEL1009 29.9 4.69 3.03 194
TUNU-SOSISI NEL1010 14.05 15.9 0.55 48
TUNU-SOSISI NEL1011 16.4 7.36 26.4 211
TUNU-SOSISI NEL1012 7.69 24.8 10.25 300
TUNU-SOSISI NEL1013 33.4 18.75 0.56 113
PIA NEL1014 29 0.78 27.4 277
PIA NEL1015 24.8 4.52 14.65 229
PIA NEL1017 28.9 0.29 22.6 221
PIA NEL1018 13 0.44 14.7 90
PIA NEL1019 14.25 6.52 14.65 165
PIA NEL1020 13.75 15.2 11.6 162
NIUA_2 NEL1024 10.75 18.5 13.15 363
NIUA_3 NEL1025 14.15 1.24 19.2 274
NIUA_3 NEL1026 16.15 4.43 13.65 302
Min 0.76 0.29 0.55 25
Max 28.9 24.8 26.4 302
Average 16.4 8.2 12.3 184
The scientific and technical information in the assay results table was
reported to the company by Teck Cominco.
The Maka SMS system is located in a water depth of approximately 1,660 metres and lies on the crest of the northeast Lau spreading centre. Sulphide outcrops up to four metres high have been mapped, using video camera and sonar instruments from an ROV, protruding from a base of predominantly pillow basalts. The strike length is currently estimated at 130 metres with a width of 100 metres.
The Tunu-Sosisi SMS system comprises three subsystems at a water depth of approximately 1,635 metres along a roughly linear zone over 1.7 kilometres that lies on a major structural zone crosscutting the southern rim of the northeast Lau caldera. All three subsystems have sulphide outcrops protruding from a soft sedimentary base. Estimated size of each of the subsystems are Tunu (150 by 100 metres), Sosisi-1 (150 by 60 metres) and Sosisi-2 (105 by 70 metres).
The Pia SMS system is located at a water depth of approximately 1,470 metres and in close proximity to a major structural zone that crosscuts the northern rim of the northeast Lau caldera. The approximate length of the system is 200 metres, with a width of 80 metres. All sulphide outcrops protrude from a soft sedimentary base.
The Niua SMS system comprises two subsystems that lie approximately 1,300 metres apart and within individual crater-like depressions. The first system, Niua-2, is at a water depth of 900 metres, and has an estimated strike length of 230 metres and width of 170 metres. The second system, Niua-3, is at a water depth of 1,180 metres, with an estimated strike length of 270 metres and width of 250 metres.
These discoveries resulted from thorough desktop analysis of all publicly available marine research data, combined with geophysical and geochemical data collected by Teck Cominco in collaboration with the following organizations:
Commonwealth Scientific and Industrial Research Organisation (CSIRO);Australian National University (ANU); National Oceanic and Atmospheric Administration (NOAA); Hawaii Institute of Geophysics and Planetology (HIGP).
- Commonwealth Scientific and Industrial Research Organisation (CSIRO);
- Australian National University (ANU);
- National Oceanic and Atmospheric Administration (NOAA);
- Hawaii Institute of Geophysics and Planetology (HIGP).
This information was used to define a follow-up ROV survey that targeted areas with the greatest prospectivity.
Teck Cominco option agreement
On Dec. 20, 2007, Teck committed to spend $12-million (U.S.) to conduct and manage a ship-based exploration program in 2008, in one or more of four designated areas in PNG, Tonga and New Zealand. Excluded from the areas are the Solwara 1 to 10 projects, a 17,500-square-kilometre area in the territorial waters of PNG, and exploration licences and applications in Tonga and Fiji applied for before Oct. 20, 2006, which remain 100 per cent owned by Nautilus. Teck Cominco will not earn an equity interest in any tenements through this $12-million (U.S.) expenditure, but rather will then have the right to select, by Dec. 31, 2008, various countries for a country earn-in.
Teck Cominco will have the exclusive right for a term of five years to form joint ventures on tenements acquired by Nautilus in certain areas since Oct. 20, 2006. Teck Cominco can earn a 40-per-cent interest in new tenements in each of the following four areas — Bismarck Sea PNG, Solomon Sea PNG, Fiji and Tonga — by spending $25-million (U.S.) in each selected area within two years of such election. For each area selected, Teck Cominco must spend a minimum of $12.5-million (U.S.) before it can withdraw with no residual interest. Upon earning a 40-per-cent interest in an area, Teck Cominco may earn an additional 10.1 per cent in each selected project area (defined as an area 100 square kilometres to 200 square kilometres) within the new tenements by spending $10-million (U.S.) on each project area.
Teck Cominco may also earn a 50.1-per-cent interest in new tenements in certain other countries and an additional 9.9 per cent in selected project areas in these countries for the same expenditures as above.
Sampling methodology
Pieces of sulphide rock averaging 3.1 kilograms were collected from the seafloor using a manipulator arm mounted on the ROV (Remora III — 25 horsepower). Samples were placed in a sample basket on the front of the ROV and then processed on board the ship. Sampling targeted material that was considered representative of the SMS system. Representative subsamples averaging 1.3 kilograms (0.55 kilogram to 2.8 kilograms) were taken from the larger samples using either a hammer or rock saw. The remaining portions of each sample were retained for reference purposes.
Laboratory analysis
All analysis was carried out by ALS Laboratory Group in Brisbane, Australia. ALS operates quality systems based on international standards ISO/IEC17025:1999, general requirements for the competence of calibration and testing laboratories, and ISO9001:2000, quality management systems — requirements.
Sample custodianship
All sampling, sample handling and analysis were completed under the supervision of Teck Cominco personnel. Sampling was carried out aboard the DEA surveyor whilst at sea. All subsamples were placed into numbered calico bags. The bagged samples were then subsequently placed into larger polyweave bags and then finally placed in boxes for secure transportation.
Quality assurance
External certified geochemical reference materials were prepared by Geostats Pty. Ltd., of Perth, Western Australia. They were independently tested along with blank samples which were interspersed at regular intervals between the 17 samples submitted for analysis.
These reference materials comprised standards with known and statistically tested concentrations of the major base and precious metals. Evaluation of these standards indicates that the quality of the analyses is within acceptable limits.
Qualified person
The exploration results reported in this news release have been compiled under the supervision of Dr. Peter Crowhurst, senior geologist, Teck Cominco Australia Ltd. Dr. Crowhurst is a member of the Australian Institute of Geoscientists, has 20 years experience as a geologist and researcher in the fields of mineral and petroleum exploration, and is a qualified person as defined under National Instrument 43-101. He consents to his name being used in this release.
