Vancouver, British Columbia - Sept. 4, 2007 - Nautilus Minerals Inc. (TSX:NUS)(AIM:NUS) -
- Targets Achieved - 92 holes completed in Solwara 1 this year
- Open at Depth - 40% of all holes end in mineralization
- Improved Recoveries - 72% recovery from sulphide intercepts
- On Track - Solwara 1 preliminary resource and mine model due end of Q4 2007
Nautilus Minerals Inc. has successfully completed the majority of the exploration fieldwork for its Solwara 1 project in the territorial waters of Papua New Guinea with 92 holes drilled to date this year within this high-grade copper and precious metal massive sulphide system.
David Heydon, Nautilus CEO, commented: "We are developing a drill-tested geological model for a seafloor massive sulphide system, with preliminary indications (using XRF-spectography) suggesting an extensive high-grade system."
"We expect assays over the coming weeks to show the tenor of the orebody system at depth, in addition to the high-grade massive sulphide chimneys/spires - often 10 metres high - that are perched upon it."
"The remote operated vehicle drill (ROVDrill) (
http://www.nautilusminerals.com/s/PhotoGallery-ROVDrill.asp) which sits on the seafloor recovering drill cores up to 19 metres in length has gone from an idea, to design, to implementation within a year. This is a significant technical achievement - and bodes well for future exploration and mining activities."
"Nautilus's exploration at Solwara 1 for the 2007 field season will be completed by late-September and laboratory assays will be available in September through October in the lead up to the announcement of a preliminary resource model later this year."
"We are now looking to future campaigns and considering new drills to increase productivity, further improve core recovery and, more importantly, provide the ability to test the systems to greater depth."
Solwara 1 Program
Since drilling commenced on June 14, 2007 at Solwara 1, 92 holes have been completed for a total of 879 metres, with an average core recovery for massive sulphide intercepts of 72%.
Selected intercepts are outlined in Table 1 and all drill holes are listed in Table 2.
This drilling is mostly adjacent to the exposed high-grade sulphide outcrop zones defined by previous surface sampling and mapping (
http://www.nautilusminerals.com/i/pdf/2007-09-04_NRM1.pdf).
The evaluation drilling of Solwara 1 is conducted on a nominal 30 metre grid with the aim of collecting sufficient samples for preparation of a mineral resource statement, metallurgical evaluation, and mine planning purposes.
As previously advised, Nautilus anticipates releasing a preliminary resources and geological model later this year, and has retained Golder Associates and SRK Consulting to provide independent technical advice in the development of a resource model consistent with 43-101 standards.
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Table 1 - Solwara 1 - 2007 ROV Drill - Selected Intercepts
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SULPHIDE INTERSECTION
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Core Cu%
recovery- Intersection hand
Drillhole Depth in Sulphide From To width held
No (m) (%) (m) (m) (m) XRF(i)
----------------------------------------------------------------------
SD065 9.6 73 0.2 8.3 8.1
hole ended
in sulphide 13.8
----------------------------------------------------------------------
SD072 15.1 41 1.7 8.2 6.5 12.2
----------------------------------------------------------------------
SD116 14.2 69 0.4 13.0 12.6
hole ended
in sulphide 14.0
----------------------------------------------------------------------
SD120 6.7 63 0.6 6.7 6.1
hole ended
in sulphide 14.5
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SD121 15.6 71 0.6 15.6 14.9
hole ended
in sulphide 8.4
----------------------------------------------------------------------
SD123 16.4 85 0.2 6.4 6.2 12.4
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(i)The hand held XRF does not analyse for Au or Ag
Geological Sequence
The improved core recovery from this year's program has revealed a geological sequence (
http://www.nautilusminerals.com/i/pdf/2007-09-04_NRM2.pdf), that is essentially consistent with land-based volcanogenic massive sulphide deposits like Kidd Creek and Horne. The surface expressions of the system are zones of chimneys up to 20m with an average height of about 5 - 10m surrounded by unconsolidated muddy sediments.
These chimney zones have been sampled at surface with a total of 146 samples reporting an average grade at Solwara 1 of 11.3% Cu, 15.2 g/t Au and 4.7% Zn. Underlying the muddy sediments and inferred to be lapping onto the chimneys is a zone of variably consolidated sandy volcaniclastic rock containing large clasts of sulfide, probably derived from fallen sulfide chimneys.
The massive sulphide zone which has been drilled locally to a maximum depth of 19m (due to limitations of drill rig) is dominated by the minerals pyrite and chalcopyrite and has a characteristic vuggy texture. The main ore zone increases in thickness towards the centre of the ore zone, to in excess of 19 metres. Many drill holes in the central spine region ended in sulphide mineralisation and remain open at depth, with 40% of all holes ending in mineralisation.
Drilling below the massive sulphide zone shows that it has a transitional contact with a zone of disseminated sulphide in altered volcanic rocks containing variable chalcopyrite mineralisation. This footwall zone has not yet been intercepted in the central part of the system, which in many terrestrial deposits has a mineralized Cu stringer zone.
The altered volcanic rocks at the base of the system are underlain in places by fresh unaltered volcanic rocks, particularly around the flanks of the ore zone. These feldspar porphyritic volcanic rocks are vesicular and likely to be andesitic to dacitic in composition.
Metallurgical testwork
Sixteen holes have been drilled to provide a metallurgical sample of 740kg which has been forwarded to Ammtec Limited in Perth, Australia to conduct testwork comprising comminution, mineralogy and bench scale froth floatation trials. This testwork will provide valuable input to the detailed concentrator plant design and provide concentrate samples for marketing purposes. These holes have also sampled the short range grade and geological variability.
Geotechnical testing
A geotechnical laboratory has been established aboard the Wave Mercury and an extensive program of geotechnical testwork has been completed on drill core from the current drilling program. In excess of 350 rock strength tests have been completed. UCS strengths in the massive sulphide zone are typically in the range from 3 MPa to 35 MPa and average about 18 MPa. The compressive strength to tensile strength ratio averages about nine.
Over 600 dry bulk density measurements have been determined using a caliper method and a water displacement method. The results from the two methods are in close agreement. The average dry bulk density of the massive sulphide zone is approximately 3.3 tonnes per cubic metre. The geotechnical testing results are consistent with independent laboratory testwork completed in 2006. Further geotechnical testwork, including triaxial testing under high confining pressures is planned for later this year.
About Nautilus Minerals Inc.
Nautilus is the first company to commercially explore the ocean floor for high grade gold-copper-zinc-silver seafloor massive sulphide deposits and is positioned to become a world leader in underwater mineral exploration. The Company's main focus for 2007 is the Solwara 1 Project, located in the territorial waters of Papua New Guinea between the island chains of New Britain and New Ireland in the western Pacific Ocean. Nautilus is listed on the TSX and on AIM, and has among its largest shareholders four of the world's largest international resource companies, including Epion (16.8%), Anglo American (6.4%), Teck Cominco (5.8%), and Barrick Gold (3.7%).
Solwara 1 ROV Drill Intercepts
Qualified Person:
The exploration results reported in this announcement have been compiled under the supervision of Anthony O'Sullivan, Chief Operating Officer of Nautilus. Mr. O'Sullivan is a member of the Australasian Institute of Mining and Metallurgy, has 20 years experience in mining and exploration geology, and is a qualified person as defined under National Instrument 43 - 101. He consents to his name being used in this release.
Results of Indicative Analyses from Hand Held XRF Unit
Nautilus is using a hand-held Niton XLT 592 X-ray florescence (XRF) instrument on the Wave Mercury to obtain indications of the grade of materials recovered from the sea floor. This system provides indicative information on grade tenor of samples for copper, zinc and lead mineralization but does not measure for many elements including gold and silver. It is unable to provide gold and silver assays.
The instrument used for this application does not provide the accuracy required to report assays. These analyses are the mean of ten point measurements on unprepared wet surfaces of each of the samples reported. XRF readings are taken at 10cm intervals along the drill core to provide indicative grade data for mineralized intervals. The instrument is not calibrated using certified standards and the samples have not been crushed and prepared to minimise matrix effects which may affect the accuracy of the analysis. However, comparison of results to date with assay data for surface samples indicate the XRF tool is a reliable method for providing indicative results of the tenor of mineralization and providing data for "real time" decisions in the field.
Measurements by hand held XRF are not assay results and do not measure gold or silver. Samples will be formally assayed by the ALS Group in Brisbane.
Laboratory Analysis
More than a thousand samples have been received by ALS Laboratory Group in Brisbane, Australia. ALS operate 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 was completed under the supervision of Nautilus personnel. Sampling was carried out aboard the Wave Mercury whilst at sea. All sub-samples were placed into numbered plastic vacuum sealed bags. The bagged samples were subsequently placed into boxes. The boxes were sealed with uniquely numbered security tags and checked upon arrival to the laboratories. A full electronic chain of custody is maintained whilst the samples are under the care of ALS.
Quality Assurance:
External certified geochemical reference materials were prepared by Geostats Pty Ltd, of Perth, Western Australia with known and statistically tested concentrations of the major base and precious metals. Standards were submitted approximately every tenth sample.
A review of sampling procedures and work processes for collection of samples at sea has been undertaken by Golders Associates with no adverse conclusions.
Table 2 - Solwara 1 ROV Drill Intercepts (holes SD065 to SD 127)
NB: Nautilus reported drill results for holes SD36-64 on July 11, 2007
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Table 2 - Solwara 1 ROV Drill Intercepts
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Water
Drillhole Depth Easting Northing Depth From To
Number (m) (m) (m) (m) (m) (m)
-----------------------------------------------------------
SD065 9.58 399388 9581261 -1501 0.2 8.3
-----------------------------------------------------------
SD066 5.06 399387 9581332 -1511 0.0 0.0
-----------------------------------------------------------
SD067 4.75 399651 9581098 -1527 0.0 3.6
-----------------------------------------------------------
SD068 9.6 399652 9581101 -1528 3.5 8.8
-----------------------------------------------------------
SD069 7.57 399642 9581096 -1526 0.0 7.6
-----------------------------------------------------------
SD070 0.9 399696 9581057 -1535 0.0 0.0
-----------------------------------------------------------
SD071 12.9 399693 9581054 -1534 5.6 12.9
-----------------------------------------------------------
SD072 15.12 399696 9581008 -1537 1.7 8.2
-----------------------------------------------------------
SD073 3.56 399696 9580954 -1544 0.0 0.0
-----------------------------------------------------------
SD074 8.42 399700 9580988 -1539 0.3 8.4
-----------------------------------------------------------
SD075 14.13 399730 9580904 -1522 0.0 14.1
-----------------------------------------------------------
SD076 9.71 399741 9580884 -1528 2.5 9.7
-----------------------------------------------------------
SD077 13.93 399774 9580871 -1534 5.0 13.9
-----------------------------------------------------------
SD078 12.28 399630 9581043 -1517 1.4 1.7
-----------------------------------------------------------
SD079 6.95 399371 9581035 -1517 0.3 7.0
-----------------------------------------------------------
SD080 13.17 399379 9581087 -1503 0.4 11.7
-----------------------------------------------------------
SD081 4.56 399314 9580988 -1517 0.0 0.0
-----------------------------------------------------------
SD082 3.59 399298 9580972 -1517 0.0 0.0
-----------------------------------------------------------
SD083 8.73 399311 9581033 -1512 0.4 5.1
-----------------------------------------------------------
SD084 4.43 399298 9581068 -1522 0.0 0.0
-----------------------------------------------------------
SD085 8.7 399318 9581096 -1516 1.7 2.3
-----------------------------------------------------------
SD086 6.63 399312 9581145 -1511 2.6 2.9
-----------------------------------------------------------
SD087 9.62 399449 958124 -1515 0.2 3.5
-----------------------------------------------------------
SD088 7.99 399448 9581156 -1515 0.7 6.5
-----------------------------------------------------------
SD089 7.86 399444 9581140 -1520 3.5 6.1
-----------------------------------------------------------
SD090 14.5 399386 9581055 -1520 2.4 8.5
-----------------------------------------------------------
SD091 6.67 399413 9581099 -1518 1.2 2.0
-----------------------------------------------------------
SD092 5.37 399413 9581077 -1519 0.0 0.0
-----------------------------------------------------------
SD093 14.43 399350 9581072 -1513 1.5 5.3
-----------------------------------------------------------
SD094 7.39 399401 9581164 -1523 2.4 6.3
-----------------------------------------------------------
SD095 4.79 399378 9581289 -1508 0.0 0.0
-----------------------------------------------------------
SD096 11.48 399367 9581255 -1506 0.0 0.0
-----------------------------------------------------------
SD097 3.95 399457 9581227 -1528 2.3 2.8
-----------------------------------------------------------
SD098 8.87 399482 9581257 -1520 0.2 8.2
-----------------------------------------------------------
SD099 13.86 399448 9581237 -1528 5.2 12.8
-----------------------------------------------------------
SD100 16.68 399398 9581222 -1498 1.8 16.7
-----------------------------------------------------------
SD101 1.72 399485 9581264 -1521 0.0 0.0
-----------------------------------------------------------
SD102 1.91 399407 9581290 -1508 0.0 0.0
-----------------------------------------------------------
SD103 2.16 399406 9581289 -1508 0.0 0.0
-----------------------------------------------------------
SD104 1.29 399359 9581037 -1517 0.7 1.3
-----------------------------------------------------------
SD105 17 399336 9581043 -1510 0.3 5.8
-----------------------------------------------------------
SD106 10.35 399362 9581045 -1516 0.7 8.6
-----------------------------------------------------------
SD107 4.92 399555 9581256 -1523 0.0 0.0
-----------------------------------------------------------
SD108 2.26 399496 9581216 -1523 0.0 0.0
-----------------------------------------------------------
SD109 10.83 399697 9581082 -1528 1.3 10.8
-----------------------------------------------------------
SD110 4.87 399697 9581102 -1533 2.7 3.3
-----------------------------------------------------------
SD111 12.75 399755 9581047 -1546 0.0 0.0
-----------------------------------------------------------
SD112 16.4 399486 9581274 -1515 0.5 16.4
-----------------------------------------------------------
SD113 9.21 399354 9581147 -1517 0.0 0.0
-----------------------------------------------------------
SD114 12.31 399675 9581030 -1526 3.3 4.3
-----------------------------------------------------------
SD115 4.75 399352 9581237 -1509 0.0 0.0
-----------------------------------------------------------
SD116 14.23 399388 9581259 -1501 0.4 13.0
-----------------------------------------------------------
SD117 4.15 399404 9581233 -1498 1.5 4.0
-----------------------------------------------------------
SD118 12.75 399150 9580933 -1501 1.2 8.6
-----------------------------------------------------------
SD119 10.18 399106 9580925 -1558 0.8 6.7
-----------------------------------------------------------
SD120 6.71 399135 9580953 -1558 0.6 6.7
-----------------------------------------------------------
SD121 15.55 399080 9580956 -1564 0.6 15.6
-----------------------------------------------------------
SD122 12.68 399074 9580930 -1570 2.6 6.8
-----------------------------------------------------------
SD123 16.42 399291 9581030 -1513 0.2 6.4
-----------------------------------------------------------
SD124 17.03 399338 9581044 -1510 0.6 4.0
-----------------------------------------------------------
SD125 8.64 399396 9581225 -1497 1.2 8.6
-----------------------------------------------------------
SD126 8.54 399398 9581215 -1500 3.3 8.5
-----------------------------------------------------------
SD127 17.5 399643 9581094 -1535 0.6 16.6
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Sulphide Intersection
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Cu%
Weighted Recovery
Sulphide Avg (Hand Sulphide
Drillhole Width Held Intercept
Number (m) XRF) (%) Comment
-----------------------------------------------------------------------
SD065 8.1 13.8 73 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD066 Volcanic rock - barren
-----------------------------------------------------------------------
SD067 3.6 8.9 78 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD068 5.4 6.1 29 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD069 7.6 4.1 86 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD070 Mechanical Fault - terminate hole
-----------------------------------------------------------------------
SD071 7.3 3.9 83 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD072 6.5 12.2 41
-----------------------------------------------------------------------
SD073 Volcanic rock - barren
-----------------------------------------------------------------------
SD074 8.1 4.7 76 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD075 14.1 6.9 47 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD076 7.2 3.7 69 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD077 9.0 2.3 72 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD078 0.3 11.0 100
-----------------------------------------------------------------------
SD079 6.7 5.9 100 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD080 11.4 12.1 54 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD081 Volcanic rock - barren (1.2m less than 1% Cu)
-----------------------------------------------------------------------
SD082 Volcanic rock - barren
-----------------------------------------------------------------------
SD083 4.7 2.6 81
-----------------------------------------------------------------------
SD084 Volcanic rock barren
-----------------------------------------------------------------------
SD085 0.6 3.2 98
-----------------------------------------------------------------------
SD086 0.3 1.2 93
-----------------------------------------------------------------------
SD087 3.3 3.7 67
-----------------------------------------------------------------------
SD088 5.8 9.1 47 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD089 2.6 7.0 91
-----------------------------------------------------------------------
SD090 6.1 1.9 64
-----------------------------------------------------------------------
SD091 0.8 2.3 85
-----------------------------------------------------------------------
SD092 Volcanic rock - barren (0.6m less than 1% Cu)
-----------------------------------------------------------------------
SD093 3.8 10.3 66
-----------------------------------------------------------------------
SD094 3.9 2.0 41 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD095 Volcanic rock - barren
-----------------------------------------------------------------------
SD096 Volcanic rock - barren
-----------------------------------------------------------------------
SD097 0.5 1.3 100 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD098 7.9 3.4 53 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD099 7.6 5.9 49 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD100 14.9 5.2 91 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD101 Mechanical Fault - terminate hole
-----------------------------------------------------------------------
SD102 Mechanical Fault - terminate hole
-----------------------------------------------------------------------
SD103 Mechanical Fault - terminate hole
-----------------------------------------------------------------------
SD104 0.6 3.9 100 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD105 5.5 7.5 73 -
-----------------------------------------------------------------------
SD106 7.9 3.6 75 -
-----------------------------------------------------------------------
SD107 Hole Collapse - thick sediments
-----------------------------------------------------------------------
SD108 Hole Collapse - thick sediments
-----------------------------------------------------------------------
SD109 9.6 7.3 93 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD110 0.5 1.2 100 Mechanical Fault -
terminate hole
-----------------------------------------------------------------------
SD111 Volcanic rock - barren
-----------------------------------------------------------------------
SD112 16.0 6.7 80 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD113 Volcanic rock - barren (minor Zn sulphides)
-----------------------------------------------------------------------
SD114 1.0 1.4 100 -
-----------------------------------------------------------------------
SD115 Mechanical Fault - terminate hole
-----------------------------------------------------------------------
SD116 12.6 14.0 69 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD117 2.5 6.5 68 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD118 7.4 1.9 26 -
-----------------------------------------------------------------------
SD119 5.9 7.1 61 -
-----------------------------------------------------------------------
SD120 6.1 14.5 63 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD121 14.9 8.4 71 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD122 4.2 6.9 41 -
-----------------------------------------------------------------------
SD123 6.2 12.4 85 -
-----------------------------------------------------------------------
SD124 3.4 5.4 78 -
-----------------------------------------------------------------------
SD125 7.4 5.3 73 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD126 5.3 4.6 73 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
SD127 16.0 3.2 98 Hole Ended in Massive
Sulphide
-----------------------------------------------------------------------
Neither the TSX nor the London Stock Exchange accept responsibility for the adequacy or accuracy of this press release.
For more information, please contact
Nautilus Minerals Inc.
Investor Relations
(778) 785-7591
Email:
investor@nautilusminerals.com
Website:
www.nautilusminerals.com
or
Australian Project Office
+61 (7) 3318 5555
Email:
ceo@nautilusminerals.com
or
Numis Securities Limited (NOMAD)
John Harrison/James Black
+44 (0) 20 7260 1000
or
Parkgreen Communications
+44 (0) 20 7851 7480