Mr. Mike Johnston reports

NAUTILUS ANNOUNCES PRELIMINARY ECONOMIC ASSESSMENT FOR ITS SOLWARA 1 PROJECT

Nautilus Minerals Inc. has released the results of a preliminary economic assessment (PEA) prepared by AMC Consultants Pty. Ltd., contained in an independent National Instrument 43-101 technical report, for the development of the Solwara 1 project in the Bismarck Sea of Papua New Guinea (PNG). All dollar amounts in this release are presented in U.S. dollars unless otherwise stated.

The PEA details the proposed production system and methodology, and provides estimates of operating costs, capex (capital expenditures) to completion, metal production and cash flows. Highlights include:

• Solwara 1 fully permitted;
• PNG government a 15-per-cent partner;
• 15-month ramp-up to steady-state production (about 3,200 tonnes per day);
• Steady-state payable metal production per quarter about 20,000 t copper and 29,000 ounces gold;
• C1 costs (1):
• • $1.36 (U.S.)/pound Cu for the entire deposit;
  • 80 U.S. cents Cu when at projected steady state (3,200 t/d);
• Undiscounted posttax net cash flow of $179-million (U.S.);
• Discounted net cash flow, discounting at 15 per cent per annum, of $56-million (U.S.);
• IRR (internal rate of return) base case 28 per cent (1), rising to 40 per cent using average forward curve metal prices for copper and gold during the production period (as at the PEA's effective date);
• About $243-million (U.S.) of capex remaining to be raised (subject to financing) and spent until production commences;
• Taxes and royalty payments from Solwara 1 are estimated to be more than $100-million (U.S.) over the three-year project life (including ramp-up).

The PEA models first production starting third quarter 2019, and also shows that the project has a high fixed cost component (about 52 per cent), largely vessel related and is highly leveraged to metal grade, metal prices, equipment utilization and production rates. The maximum capacity of the production system is designed at about 6,000 tpd. AMC believes that if a steady-state production rate of 4,500 tpd is achieved, not an unreasonable target in its assessment, then C1 costs would be expected to be lowered to around 62 U.S. cents per pound Cu (net of byproducts), well in the lower half of the first quartile of the world copper production curve.

Mike Johnston, Nautilus's chief executive officer, commented: "We are very excited by the results of the PEA. Expected C1 operating costs at $1.36 (U.S.)/pound Cu for the entire project are in the lower half of the cost curve, and include the 15-month ramp-up period. Expected steady-state C1 operating costs of 80 U.S. cents per pound Cu sit comfortably in the lower half of the first quartile of the production curve, and highlight the potentially seriously disruptive nature of sea floor mining to the world's mining industry. These are very competitive capital and operating costs, and have additional room to move."

The production systems on which the PEA is based are currently under construction.

The Nautilus business model is based on using the capital, IP (intellectual property), and know how that Nautilus has developed for the Solwara 1 project, and applying it to future discoveries at minimal additional capex cost, and with a much reduced ramp-up curve for subsequent projects.

The oceans have significant potential to provide the key minerals (copper, gold, silver, zinc, nickel, cobalt and manganese) needed by the world as it transitions to a low-carbon future based on electric vehicles and batteries. Nautilus's sea floor production system with its very small environmental footprint, lack of tailings, and industry-leading opex (operating expenditures) and capex costs, will allow the company and its partner, Eda Kopa (Solwara) Ltd. to lead the world in this exciting new industry.

About AMC and the technical report

The company's subsidiary, Nautilus Minerals Niugini Ltd., engaged AMC to undertake the PEA for the Solwara 1 project and compile a technical report compliant with National Instrument 43-101. AMC is one of the world's most trusted mining consulting companies and operates from eight offices in Australia, Canada, Singapore, Russia and the United Kingdom. It helps mining leaders find smarter ways to mine and unearth hidden business value. AMC provides specialist services in geology and mineral resource estimation, mining engineering, mineral processing, geometallurgy, and geotechnical engineering. Its global team of experts prepares mine feasibility studies, conducts studies to optimize and improve operating mines, and provides specialist technical reports for corporate and financial transactions. AMC has a long record of producing high-quality results that provide confidence to explorers, miners and investors.

The company is today filing the technical report dated Feb. 27, 2018, prepared by AMC entitled "Nautilus Solwara 1 PEA." The authors of the technical report, all of whom are qualified persons under NI 43-101, are Ian Thomas Lipton, Edward Vincent Gleeson and Peter Munro. The technical report will be available under the company's profile on the SEDAR website as well as on the company's website.

About Solwara 1

The Solwara 1 project is a deep-sea mining project located in the Bismarck Sea of PNG. Construction of a commercial-scale mining operation to extract deep-sea metallic mineral resources is well advanced. Production has not yet occurred.

The preliminary economic assessment is based on the existing mineral resource estimate at the Solwara 1 project. The company cautions that the PEA is preliminary in nature, that it includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that the PEA will be realized. A prefeasibility study has not been undertaken. Mineral resources that are not mineral reserves do not have demonstrated economic viability.

All scientific and technical information contained in this news release has been reviewed and approved by Ian Lipton, principal geologist at AMC, who is a qualified person under NI 43-101.

(1) Notes

The PEA is based on a first production date of the third quarter of 2019. The company is currently forecasting a second quarter 2019 first production date (subject to financing), but this is also subject to finalizing the ship build contract delivery date between Mawei Shipyard and MAC, and finalizing the integration philosophy and methodology (due early second quarter of 2018). The PEA's effective date is Jan. 1, 2018. Metal prices used in the PEA's base case were $7,319/t copper, $1,200/ounce gold, $18/ounce silver. The upside case used copper and gold prices averaged over the forward curve for the proposed production period (out to second quarter of 2022), on the effective date (Jan. 1, 2018), and were estimated by AMC using $7,981/tonne Cu, and $1,391/ounce Au prices. All other cost and production parameters are detailed in the PEA.

C1 cash costs per pound are a financial performance measure based on cost of sales and includes treatment and refinement charges and byproduct credits, but excludes the impact of depreciation and royalties. C1 does not have any standardized meaning under generally accepted accounting principles (GAAP) or international financial reporting standards, and may not be comparable with similar measures of performance presented by other companies.

About Nautilus Minerals Inc.

Nautilus is the first company to explore the ocean floor for polymetallic sea floor massive sulphide deposits. Nautilus was granted the first mining lease for such deposits at the prospect known as Solwara 1, in the territorial waters of Papua New Guinea, where it is aiming to produce copper, gold and silver. The company has also been granted its environmental permit for this site.

We seek Safe Harbor.