Nautilus Minerals Inc.: High Grade Assays Confirmed at Solwara 5, 6 and 7

Nautilus Minerals Inc.’s new assay results confirm the high-grade gold-copper-zinc mineralization of its recent Solwara 5, 6 and 7 discoveries, located in the territorial waters of Papua New Guinea.

Laboratory testing of 24 samples across the three prospects returned an average grade of 17.5 grams per tonne gold, 8.94 per cent copper, 16.84 per cent zinc and 298 g/t silver.

David Heydon, Nautilus chief executive officer, commented, “These results further validate the Solwara district’s prospectivity and more specifically our highly successful May exploration program which yielded four new prospects in four weeks prior to the survey ship returning to Solwara 1 for a major drilling program.”

Mr. Heydon added, “Whilst the company’s focus is to bring to production its first mine at Solwara 1 with a nameplate production being designed around two million tonnes per annum, these additional high-grade prospects provide a potential pipeline of projects which would be necessary if the company is to look at expanding production with the addition of a second mining ship or at extending the mine life of a single-ship operation.”

SOLWARA 5,6,7 PROSPECTS — 2007 SURFACE SAMPLING

Prospect No. of samples Gold g/t Copper % Zinc % Lead % Silver g/t

Solwara 5 13 17.37 6.72 7.78 1.48 273

Solwara 6 4 18.10 14.24 18.66 0.83 217

Solwara 7 7 17.15 5.87 24.08 1.67 404

—- ——- —— ——- —— —–

Total/average 24 17.54 8.94 16.84 1.33 298

Sampling was recovered using a Triton 200 series remote-operated vehicle at water depths from 1,650 metres to 1,800 metres.

A total of 24 samples were collected using the ROV manipulator arm to grab sulphide samples directly from the sea floor.

Sample sizes ranged from two kilograms to 200 kg with a representative nominal sample of two kg dispatched to ALS Laboratory Group in Brisbane, Australia, for analysis.

Mr. Heydon, Nautilus CEO, added, “The assays in this particular case are on average 16 per cent higher for copper and 9 per cent higher for zinc than reported on May 15, 2007, and suggest the XRF units can play an important preliminary guide to keep the market informed of relative prospectivity, in advance of full laboratory results given the one-to-two-month time lag of recovering samples and getting them off the ship, back to Australia and assayed.”

A more detailed table, a reconciliation of the XRF to assay results, and commentary on sampling are included with this press release.

The Solwara 5 prospect is located at latitude 3.775 degrees south, longitude 152.079 degrees east, approximately two km to the northwest of the Solwara 1 prospect in a water depth approximately 1,650 metres. Sulphide outcrops up to two m high have been mapped, using camera and sonar instruments deployed from a remote-operated vehicle, protruding from soft sediment over a strike length of 250 m and a width of 150 m.

The Solwara 6 prospect is located at latitude 3.728 degrees south, longitude 151.681 degrees east, approximately one km to the east of the Solwara 4 prospect in a water depth approximately 1,750 m. Sulphide outcrops up to seven m high have been mapped, using camera and sonar instruments deployed from an ROV, over a strike length of 180 m and a width of 50 to 100 m.

The Solwara 7 prospect is located at latitude 3.717 degrees south, longitude 151.673 degrees east, approximately 700 m to the north of the Solwara 4 prospect in a water depth approximately 1,800 m. Sulphide outcrops up to 18 m high have been mapped, using camera and sonar instruments deployed from an ROV, over a strike length of 200 m and with a width of 50 to 100 m.

The Solwara 8 assays are expected within the next four weeks.

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 of 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.

Comparison of XRF unit and assay samples for Solwara 5, 6 and 7

Comparison with hand-held XRF results

A hand-held Niton XLT 592 X-ray fluorescence instrument was used aboard the Wave Mercury to obtain indications of the grade recovered from the sea floor.

The accompanying table shows the comparison between the assay results returned from ALS Laboratory Group and the previously reported in Stockwatch hand-held XRF results. These results compare well for copper and zinc with the assay results returning values that are 16 per cent higher for copper and 9 per cent higher for zinc.

Laboratory analysis

All analysis was carried out by ALS Laboratory Group in Brisbane, Australia. ALS operates quality systems based on international standards ISO/IEC 17025:1999, “General requirements for the competence of calibration and testing laboratories,” and ISO 9001:2000, “Quality Management Systems — Requirements.”

Sample custodianship

All sampling, sample handling and analysis were completed under the supervision of Nautilus personnel. Sampling was carried out aboard the Wave Mercury whilst at sea. All subsamples were placed into numbered plastic vacuum-sealed bags. The bagged samples were then subsequently placed into boxes. The boxes were sealed with security tape and signed by the supervising geologist on site at the time.

Quality assurance

External certified geochemical reference materials were prepared by Geostats Pty. Ltd., of Perth, Western Australia, and independently tested, and field duplicate samples were interspersed at regular intervals between the 24 samples submitted for analysis.

These reference materials comprised standards, with known and statistically tested concentrations of the major base and precious metals. Standards were submitted approximately every 10th sample. Evaluation of these standards indicate that the quality of the analyses are within acceptable limits.

SOLWARA PROJECT 2007 SAMPLING — ASSAY — HAND-HELD XRF COMPARISON

Assay XRF

Cu Zn Pb Au Ag Cu Zn Pb

Sample % % % g/t g/t % % %

Solwara 5

SUSU_07_CH_007 24.7 0.46 0.1 27.7 99 20.8 0.5 0

SUSU_07_CH_008 15.2 6.57 0.51 17.4 172 13.9 1.7 0.1

SUSU_07_CH_014 0.18 17.1 2.17 3.96 433 0.4 15.9 1.5

SUSU_07_CH_006 0.09 8.14 2.33 0.05 189 0.4 11.1 1.2

SUSU_07_CH_005 16.8 3.74 0.22 48.8 218 13 4.5 0.1

SUSU_07_CH_004 13.6 13 0.88 32.8 360 12.7 8.3 0.4

SUSU_07_CH_009 0.14 9.91 9.16 2.39 977 0.4 11.6 4.7

SUSU_07_CH_010 0.1 15.35 1.06 19.05 233 0.7 16.4 0.4

SUSU_07_CH_005 15.9 1.98 0.17 50.2 171 14.8 0.7 0

SUSU_07_CH_012 0.08 5.43 0.89 0.08 157 0.4 13.8 0.6

SUSU_07_CH_013 0.44 12.95 0.81 22.7 309 0.8 9.4 0.3

SUSU_07_CH_011 0.08 3.17 0.43 0.69 104 0.4 6.9 0.2

SUSU_07_RK_029 0.11 3.37 0.53 0.01 129 0.4 7.1 0.9

—- —- —- —– —– —- —- —

Solwara 5

average 6.72 7.78 1.48 17.37 273.1 6.08 8.30 0.8

Solwara 6

PUAL_07_CH_003 26.6 5.68 0.28 20.3 143 18.4 6.6 0.4

PUAL_07_CH_002 0.15 34.3 1.14 12.8 226 0.6 31.6 0.7

PUAL_07_CH_005 30 3.47 0.22 27.3 157 28 3.2 0.3

PUAL_07_CH_004 0.19 31.2 1.65 12 345 0.5 32.3 1

—– —– —- —– —– —– —– —

Solwara 6

average 14.24 18.66 0.82 18.10 217.7 11.88 18.43 0.6

Solwara 7

PUAL_07_CH_006 12.9 12.1 0.32 11.55 162 5.7 6 2.6

PUAL_07_CH_013 4.9 25.5 0.71 39.3 464 4.2 13.4 0.2

PUAL_07_CH_012 0.08 25.2 6.16 0.12 541 0.4 29.3 3

PUAL_07_CH_017 1.28 43.1 1.3 37.6 823 2.9 25.2 0.3

PUAL_07_CH_014 3.13 23.7 0.68 18.7 272 4.2 21.5 0.4

PUAL_07_CH_016 18.5 8.39 0.41 7.96 116 13.6 9.3 0.2

PUAL_07_CH_018 0.28 30.6 2.1 4.84 451 0.5 29.4 1.6

—- —– —- —– —– —- —– —-

Solwara 7

average 5.87 24.08 1.67 17.15 404.1 4.50 19.16 1.19

(i)UTM zone 56 (WGS 84)