Key points
- Certified assay results confirmed gold grades up to 20.8 grams per tonne and copper grades up to 37.7 per cent from holes drilled late last year at Solwara 1.
- Recent XRF analysis of holes drilled since Jan. 6 identified intersects including 12.57 metres averaging 9.4 per cent copper in hole SD197 and 9.28 metres averaging 12.2 per cent copper in hole SD192.
- Since Jan. 6, 2011, Nautilus has drilled 10 additional holes at nine locations for a total of 163.7 metres.
- Drilling has been carried out since mid-November aboard the vessel Rem Etive using the ROVdrill3 wireline diamond drill system provided by TSMarine.
Gold grades of up to 20.8 grams per tonne and copper grades of up to 37.7 per cent have been confirmed in assay results from sea floor drilling at the Nautilus Minerals Inc. Solwara 1 project in the Bismarck Sea in Papua New Guinea.
The certified assay results relate to the series of holes drilled late last year and confirm the preliminary analysis through hand-held X-ray fluorescence (XRF), which was reported in December, 2010.
More recent drilling, carried out as part of the continuing exploration campaign since Jan. 6, has continued to identify high-grade mineralization. XRF analysis has revealed intersects including 12.57 metres averaging 9.4 per cent copper (hole SD197) and 9.28 metres averaging 12.2 per cent copper (hole SD192). (Note: XRF results are subject to confirmation).
Nautilus’s chief executive officer, Steve Rogers, said the drilling results continued to show the high-grade nature of the Solwara 1 deposit.
“Laboratory assay results such as these demonstrate the remarkable combination of high copper grades and gold mineralization in this deposit. We are now drill testing additional SMS zones, both on the recently granted mining lease at Solwara 1 and on highly prospective surrounding discoveries,” he said.
A table provides the laboratory assay results from analysis of drilling carried out late last year. Preliminary XRF analysis of these intervals was previously released by Nautilus in Stockwatch on Dec. 16, 2010.
MINERALIZED INTERSECT REPORT FROM SELECTED HOLES DRILLED AT SOLWARA 1
(BASED ON LABORATORY ASSAY RESULTS)
Interval Recovery
Interval Interval length for Copper Zinc Au Ag
Hole ID from (m) to (m) (m) interval (%) (%) g/t g/t
SD166 1.84 2.94 1.10 100% 21.2 0.3 16.7 37.4
including 1.84 1.99 0.15 100% 37.7 BDL 12.9 26.0
1.99 2.57 0.58 100% 17.0 0.4 20.8 38.0
SD167 2.02 21.22 19.20 13% 8.6 0.7 4.3 30.5
SD169 2.08 13.57 11.49 49% 5.0 0.1 2.8 9.2
SD172 1.98 10.20 8.22 25% 12.6 0.1 9.2 24.3
Note: Certified results for hole SD171 and all holes after SD173 are pending.
BDL: Below detection limit.
Since the drilling results announced in Stockwatch on Jan. 6, 2011, 10 additional holes have been drilled at nine locations for a total of 163.7 metres.
Preliminary analysis of recovered drill core from the additional drilling continues to demonstrate the presence of high-grade mineralization at all drill sites. Results are summarized in a table.
INITIAL MINERALIZED INTERSECT REPORT FROM SELECTED HOLES DRILLED AT SOLWARA 1
(BASED ON XRF ANALYSIS OF PULP RESIDUES)
Copper
mineralization
intersected
below
previously
modelled
Reco- depth of
End Inter- Inter- Inter- very massive
of val val val for Cop- sulphide
Hole hole from to length inter- per Zinc (m)
ID (m) (m) (m) (m) val (%) (%) Comment (1)
Intervals
separated by
significant
zone of core
loss. Hole
SD188 29.37 0.48 4.37 3.89 79% 17.0 0.2 ended in non-
mineralized
6.31 7.85 1.54 26% 6.4 0.1 footwall. -2.2
Intervals
separated by
significant
zone of core
loss. Hole
ended in non-
mineralized
footwall.
SD189 23.27 0.61 1.24 0.63 100% 28.5 0.1 Almost no
recovery
4.15 7.68 3.53 36% 13.1 0.1 below 8.77 m. 2.5
No core was
recovered
below 7.75 m.
Mineralization
is open
SD190 14.94 3.09 7.75 4.66 29% 11.2 1.7 to depth. (2)
SD191 SD191 was abandoned at 1.94 m due to mechanical issues and
redrilled by SD192.
Hole ended in
non-mineralized
SD192 15.53 1.00 10.28 9.28 57% 12.2 0.1 footwall. 2.0
Hole ended in
non-mineralized
SD193 7.00 2.07 3.00 0.93 100% 14.1 0.1 footwall. -2.7
Copper
mineralization
was recorded
in the footwall
to a depth of
14.1 m. Hole
ended in non-
mineralized -0.9
SD194 20.81 1.56 9.36 7.80 49% 12.9 1.0 footwall. (3)
No core was
recovered below
the reported
interval.
Mineralization
is open
SD195 5.02 0.09 4.04 3.95 78% 18.2 0.8 to depth. (4)
Hole ended in
non-mineralized
SD196 26.12 1.45 4.57 3.12 42% 15.2 0.1 footwall. -1.5
Intervals
separated by
zone of core
loss and
low-grade
material.
SD197 19.69 1.79 2.51 0.72 100% 15.1 1.4 Hole ended in
non-mineralized
4.00 16.57 12.57 61% 9.4 0.9 footwall. 3.7
(1) Negative values indicate a base of mineralization closer to the surface than the previously modelled base of massive sulphide.
(2) No core was recovered in the interval necessary to make an assessment.
(3) Does not include copper mineralization in footwall units separated by significant zones of core loss.
(4) Hole was abandoned due to mechanical issues above the previously modelled base of massive sulphide.
REM Etive drilling program
Nautilus has been drilling since mid-November on board the vessel Rem Etive, using the ROVdrill3 drilling system. TSMarine is providing the vessel, operating crew, remotely operated vehicles (ROVs) and drilling equipment required for the project. The ROVdrill3 drilling system is a wireline diamond drill designed to recover up to 80 metres of 70-millimetre diameter core.
A full listing of all intersections and core recovery can be seen in separate tables.
Technical information
Detailed information on the drilling program, selection of reported intervals, drilling details, treatment of core loss, sampling procedures, XRF analysis and quality assurance/quality control was reported previously in the news release in Stockwatch on Dec. 16, 2011.
Laboratory analysis
Sample assaying was completed by laboratories of SGS Australia Pty. Ltd. SGS operates quality systems based on international standards ISO/IEC17025:1999 “General Requirements for Competence of Calibration and Testing Laboratories,” and ISO9001:2008 “Quality Management Systems — Requirements.” SGS’s Australian mineral services are also accredited by Australia’s National Association of Testing Authorities (NATA).
Gold is determined by fire assay using a lead collection technique with a 30-gram sample charge weight. Previous homogeneity studies carried out on material from Solwara 1 indicate that this is a suitable subsample size to avoid any “nugget effect” for gold.
Copper, zinc and silver are analyzed by ICP-OES after a high-temperature aqua regia digest. Samples returning values above the upper limit of this technique are reanalyzed by an AAS method. Field duplicate pairs and a range of externally check samples (CRMs) with certified values of gold and base metals are inserted within the sample sequence by Nautilus before sample submittal. Analysis results for these check samples indicate acceptable precision and accuracy for the purpose of reporting exploration results.
Qualified person
The exploration results reported in this announcement have been compiled under the supervision of Nautilus’s resource leader, Thomas Sant. Mr. Sant, a fellow of the Geological Society of London, a United Kingdom chartered geologist and a registered European geologist, has over 16 years experience in mineral exploration seeking hydrothermal systems, and is a qualified person as defined by National Instrument 43-101. Mr. Sant has reviewed and approved the technical disclosure contained in this news release.
