EXHIBIT 99.1

ANNUAL INFORMATION FORM

FOR THE YEAR ENDED DECEMBER 31, 2023 

This annual information form ("AIF") is as of April 1, 2024  

Item 1. Table of Contents

Item 2. Preliminary Notes

This AIF contains "forward-looking information" within the meaning of applicable Canadian securities legislation. Wherever possible, words such as "plans", "expects", or "does not expect", "budget", "scheduled", "estimates", "forecasts", "anticipate" or "does not anticipate", "believe", "intend" and similar expressions or statements that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved, have been used to identify forward-looking information.

Forward-looking information in this AIF include, without limitation, statements regarding:

Forward-looking information is based on the reasonable assumptions, estimates, analyses and opinions of management made in light of its experience and its perception of trends, current conditions and expected developments, as well as other factors that management believes to be relevant and reasonable in the circumstances at the date that such statements are made, but which may prove to be incorrect. We believe that the assumptions and expectations reflected in such forward-looking information are reasonable.

Key assumptions upon which the Company’s forward-looking information are based include:

Such Forward Looking Statements related to the 2023 Preliminary Economic Assessment (the "2023 PEA") (discussed below in Description of Business) also include (i) the project plan for the Pebble Project, as defined by the Proposed Project and various Potential Expansions Scenario and including the financial results of the 2023 PEA, including net present value and internal rates of return, and the ability of the Pebble Partnership to secure the financing to proceed with the development of the Pebble Project, including any stream financing and infrastructure outsourcing; (ii) the social integration of the Pebble Project into the Bristol Bay region and benefits for Alaska, (iii) the political and public support for the permitting process, (iv) the exploration potential of the Pebble Project, (v) the future demand for copper, gold and other metals; and (vi) the potential addition of partners in the Pebble Project. Although the Company believes the expectations expressed in these forward-looking statements are based on reasonable assumptions, such statements should not be in any way be construed as guarantees that the Pebble Project will secure all required government permits, establish the commercial feasibility of the Pebble Project, achieve the required financing, or develop the Pebble Project. The 2023 PEA is preliminary in nature and includes Inferred mineral resources that are considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no assurance that the 2023 PEA will be realized. Mineral Resources that are not mineral reserves do not have demonstrated economic viability, and there is no assurance that the Pebble Project mineral resources will ever be upgraded to reserves. Forward-looking statements are necessarily based upon a number of factors and assumptions that, while we considered as of the date of such statements, are inherently subject to significant business, economic and competitive uncertainties and contingencies and such statements should not be in any way be construed as guarantees that the Pebble Project will secure all required government permits, establish the commercial feasibility of the Pebble Project, achieve the required financing or develop the Pebble Project.

Such forward looking statements or information related to the 2023 PEA include but are not limited to statements or information with respect to the mined and processed material estimates, the internal rate of return, the annual production, the net present value, the life of mine, the capital costs, operating costs estimated for each of the Proposed Project and the expansion scenarios for the Pebble Project, other costs and payments for the proposed infrastructure for the Pebble Project (including how, when, where and by whom such infrastructure will be constructed or developed), projected metallurgical recoveries, plans for further development, and securing the required permits and licenses for further studies to consider expansion of the operation, market price of precious and base metals, or other statements that are not statement of fact.  Additional assumptions we used to develop forward-looking statements related to the 2023 PEA also include the assumptions that (i) the Pebble Project will obtain all required environmental and other permits and all land use and other licenses without undue delay, (ii) any feasibility studies prepared for the development of the Pebble Project will be positive, (iii) the Company’s estimates of mineral resources will not change, and the Company will be successful in converting mineral resources to mineral reserves, (iv) the Company will be able to establish the commercial feasibility of the Pebble Project and (v) third parties will be prepared to participate in the development of the Pebble Project through the undertaking of the development of infrastructure required for the mine (eg. marine terminal, access roads, natural gas pipelines, mine site power plant) .

Readers are cautioned that the foregoing list is not exhaustive of all factors and assumptions which may have been used. Forward looking statements are also subject to risks and uncertainties facing our business, any of which could have a material impact on our outlook.

Some of the risks and uncertainties that could cause actual results to differ materially from those expressed in the forward-looking statements include:

The likelihood of future mining at the Pebble Project is subject to a large number of risks and will require achievement of a number of technical, economic and legal objectives, including (i) obtaining necessary mining and construction permits, licenses and approvals without undue delay, including without delay due to third party opposition or changes in government policies, (ii) the finalization of the project plan for the Pebble Project, including the financial results of the 2023 PEA, (iii) the completion of feasibility studies demonstrating that any Pebble Project mineral resources that can be economically mined, (iv) the completion of all necessary engineering for mining, processing and infrastructure facilities, (v) our ability to secure a partner for the development of the Pebble Project, and (vi) our receipt of significant additional financing, including that associated with the full Royalty Agreement, to fund these objectives as well as funding mine construction.

This list is not exhaustive of the factors that may affect any of the Company’s forward-looking statements or information. Forward-looking statements or information are statements about the future and are inherently uncertain, and actual achievements of the Company or other future events or conditions may differ materially from those reflected in the forward-looking statements or information due to a variety of risks, uncertainties, and other factors, including, without limitation, the risks and uncertainties described above. See "Risk Factors" on page 57 and the risk factors and related discussions in our Management Discussion and Analysis for the year ended December 31, 2023 (our "2023 Annual MD&A").

Our forward-looking statements are based on the reasonable beliefs, expectations, and opinions of management on the date of this AIF. Although we have attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. There is no assurance that such information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such information. Accordingly, readers should appreciate the inherent uncertainty of, and not place undue reliance on, forward-looking information. We do not undertake to update any forward-looking information, except as, and to the extent required by, applicable securities laws.

Incorporation of Continuous Disclosure Documents by Reference

In this AIF, the "Company" or "Northern Dynasty" refers to Northern Dynasty Minerals Ltd. and all its subsidiaries and affiliated partnerships together unless the context states otherwise.

Currency and Metric Equivalents

All dollar amounts are expressed in Canadian dollars unless otherwise indicated. The Company’s accounts are maintained in Canadian dollars. The daily rate of exchange as reported by the Bank of Canada for the conversion of one Canadian dollar into one United States dollar ("U.S. dollar") on December 29, 2023, being the last business day, was $1.3226.

On March 28, 2024, the rate of exchange of the Canadian Dollar, based on the daily rate in Canada as published by the Bank of Canada, was US$1.00 = $1.3550.  Exchange rates published by the Bank of Canada, available on its website www.bankofcanada.ca, are nominal quotations - not buying or selling rates - and intended for statistical or analytical purposes.

The following tables set out the exchange rates, based on the daily rates in Canada as published by the Bank of Canada for the conversion of Canadian Dollars into U.S. dollars.

For ease of reference, the following factors for converting metric measurements into Imperial equivalents are as follows:

Glossary

In this AIF the following terms have the meanings set forth herein:

Regulatory Terms:

Technical Terms:

Unit Abbreviations

Canadian Mineral Property Disclosure Standards and Resource Estimates

The discussion of mineral deposit classifications in this AIF uses the certain technical terms presented below as they are defined in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Definition Standards on mineral resources and reserves (the "CIM Standards") adopted by the CIM Council, as required by NI 43-101.  The following definitions are reproduced from the latest version of the CIM Standards, which were adopted by the CIM Council on May 10, 2014 (the "CIM Definitions").  Estimated mineral resources fall into two broad categories dependent on whether the economic viability of them has been established and these are namely "resources" (potential for economic viability) and "reserves" (viable economic production is feasible).  Resources are sub-divided into categories depending on the confidence level of the estimate based on level of detail of sampling and geological understanding of the deposit.  The categories, from lowest confidence to highest confidence, are inferred resource, indicated resource and measured resource.  The Company does not claim to have any reserves currently.  The CIM definitions are as follows:

Cautionary Notes to United States Investors Concerning Canadian Mineral Property Disclosure Standards

As a Canadian issuer, Northern Dynasty is required to comply with reporting standards in Canada that require that we make disclosure regarding our mineral properties, including any estimates of mineral reserves and resources, in accordance with NI 43-101. NI 43-101 is a rule developed by the Canadian Securities Administrators that establishes standards for all public disclosure an issuer makes of scientific and technical information concerning mineral projects.  In accordance with NI 43-101, the Company uses the terms mineral reserves and resources as they are defined in accordance with the CIM Definition Standards on mineral reserves and resources adopted by the CIM. 

The United States Securities and Exchange Commission (the "SEC") adopted amendments to its disclosure rules (the "SEC Modernization Rules") to modernize the mineral property disclosure requirements for issuers whose securities are registered with the SEC under the US Securities Exchange Act of 1934 (the "U.S. Exchange Act").  The SEC Modernization Rules include the adoption of definitions of the following terms, which are substantially similar to the corresponding terms under the CIM Definition Standards that are presented above under "Canadian Mineral Property Disclosure Standards and Resource Estimates":

With the adoption of the SEC Modernization Rules, the SEC recognizes estimates of "measured mineral resources", "indicated mineral resources" and "inferred mineral resources". In addition, the SEC amended its definitions of "proven mineral reserves" and "probable mineral reserves" to be substantially similar to the corresponding CIM Definitions.

Northern Dynasty is not required to provide disclosure on our mineral properties, including the Pebble Project, under the SEC Modernization Rules as we are presently a "foreign issuer" under the US Exchange Act and entitled to file continuous disclosure reports with the SEC under the Multi-Jurisdictional Disclosure System ("MJDS") between Canada and the United States. Accordingly, we anticipate that we will be entitled to continue to provide disclosure on our mineral properties, including the Pebble Project, in accordance with NI 43-101 disclosure standards and CIM Definition Standards. However, if we either cease to be a "foreign issuer" or cease to be entitled to file reports under the MJDS, then we will be required to provide disclosure on our mineral properties under the SEC Modernization Rules. Accordingly, United States investors are cautioned that the disclosure that we provide on our mineral properties, including the Pebble Project, in the AIF and under our continuous disclosure obligations under the US Exchange Act, may be different from the disclosure that we would otherwise be required to provide as a US domestic issuer or a non-MJDS foreign issuer under the SEC Modernization Rules.

United States investors are cautioned that while the above terms are substantially similar to CIM Definitions, there are differences in the definitions under the SEC Modernization Rules and the CIM Definition Standards. Accordingly, there is no assurance any mineral resources that we may report as "measured mineral resources", "indicated mineral resources" and "inferred mineral resources" under NI 43-101 would be the same had we prepared the resource estimates under the standards adopted under the SEC Modernization Rules.

Investors are cautioned not to assume that any "measured mineral resources", "indicated mineral resources", or "inferred mineral resources" that we report in this AIF are or will be economically or legally mineable.

Further, "inferred resources" have a great amount of uncertainty as to whether they can be mined legally or economically. In accordance with Canadian securities laws, estimates of "inferred mineral resources" cannot form the basis of feasibility or other economic studies, except in limited circumstances where permitted under NI 43-101.

For the above reasons, information contained in this AIF and the documents incorporated by reference herein containing descriptions of our mineral deposits may not be comparable to similar information made public by United States companies subject to the reporting and disclosure requirements under the United States federal securities laws and the rules and regulations thereunder.

Item 3. Corporate Structure

Northern Dynasty is a mineral exploration company incorporated on May 11, 1983, pursuant to the Company Act of the Province of British Columbia (predecessor statute to the British Columbia Corporations Act in force since 2004), under the name "Dynasty Resources Inc." On November 30, 1983, the Company changed its name to "Northern Dynasty Explorations Ltd." and subsequently, on October 11, 1997, changed its name to Northern Dynasty Minerals Ltd. Northern Dynasty became a reporting company in the Province of British Columbia on April 10, 1984 and was listed on the Vancouver Stock Exchange (now absorbed by the TSX Venture Exchange and herein generally "TSX-V") from 1984-1987, listed on the Toronto Stock Exchange ("TSX") from 1987-1993, and delisted from trading but continued to comply with its continuous disclosure obligations from 1993 to 1994, and thereafter listed on TSX-V from 1994 to October 30, 2007, when it again began trading on the TSX. In November 2004, the common shares of Northern Dynasty were also listed on the American Stock Exchange ("AMEX"). AMEX was purchased by the New York Stock Exchange ("NYSE") and the Company now trades on the NYSE American Exchange ("NYSE American").

The head office of Northern Dynasty is located at 1040 West Georgia Street, 14th floor, Vancouver, British Columbia, Canada V6E 4H1, telephone (604) 684-6365, facsimile (604) 639-9209. The Company’s legal registered office is in care of its Canadian attorneys, McMillan LLP, Barristers & Solicitors, at Suite 1500, 1055 West Georgia Street, Vancouver, British Columbia, Canada V6E 4N7, telephone (604) 689‑9111, facsimile (604) 685‑7084.

The Company’s Alaska mineral resource exploration business is operated through a wholly-owned Alaskan registered limited partnership, the Pebble Limited Partnership (the "Pebble Partnership" or "PLP"), in which the Company owns a 100% interest through an Alaskan general partnership, the Northern Dynasty Partnership, which is a partnership formed by the Company and a wholly-owned subsidiary. An indirectly wholly-owned subsidiary of the Company, Pebble Mines Corp. is the general partner of the Pebble Partnership and responsible for its day-to-day operations. The business address of the Northern Dynasty Partnership is Suite 405, 2525 Gambell Street, Anchorage, Alaska, USA, 99503.

In this AIF, a reference to the "Company" or "Northern Dynasty" includes a reference to PLP and the Company’s wholly-owned subsidiaries and other consolidated interests and entities, unless the context clearly indicates otherwise. Certain terms used herein are defined in the text and others are included in the glossary of this AIF.

Item 4. General Development of the Business

Company Development

Northern Dynasty is a mineral exploration company focused on the exploration and advancement towards feasibility, permitting and ultimately development of the Pebble Project, a copper-gold-molybdenum-silver-rhenium mineral project located in southwest Alaska (the "Pebble Project" or the "Project"). The Pebble Project is comprised of mineral claims that are held by subsidiaries of the Pebble Partnership, which is a 100% wholly-owned subsidiary of Northern Dynasty.

Northern Dynasty acquired a 100% interest in the Pebble Project from an Alaskan subsidiary of Teck Resources Limited ("Teck") in a series of transactions from October 2001 through to June 2006. Teck has retained certain royalties in the Pebble Project, as described below under Item 5 – Description of Business.

The Pebble Partnership was converted into a limited partnership in July 2007 in connection with a joint venture for the Pebble Project entered into between the Company and an affiliate of Anglo American plc ("Anglo American"). From July 2007 to December 2013, approximately US$573 million was provided to the Pebble Partnership by the affiliate of Anglo American, largely spent on exploration programs, resource estimates, environmental data collection and technical studies, with a significant portion spent on engineering of various possible mine development models and related infrastructure, power and transportation systems. The technical and engineering studies that were completed during the period prior to December 2013 relating to mine-site and infrastructure development provide background support for management’s current understanding of the most likely development scenarios for the Project. However, the scenarios evaluated during that period are not considered to be current. Accordingly, the Company is uncertain as to the extent to which it can realize significant value from this prior work. Environmental baseline studies and data, as well as geological information from exploration, remain important information available to the Company from this period in continuing its advancement of the Project. Anglo American withdrew from the Pebble Partnership effective December 10, 2013.

In December 2017, Northern Dynasty and First Quantum Minerals Ltd. ("First Quantum" or collectively, the "parties") entered into a framework agreement, which contemplated that the parties would execute an option agreement whereby First Quantum could earn a 50% interest in the Pebble Partnership. First Quantum also made a non-refundable early option payment of US$37.5 million to be applied solely for the purpose of progressing permitting of the Pebble Project. On May 25, 2018, the Company announced that the parties had been unable to reach agreement on the option and partnership transaction contemplated in the December 2017 framework agreement, and it was terminated in accordance with its terms.

Northern Dynasty holds a 100% interest in the Pebble Partnership and the Pebble Project. Northern Dynasty continues its efforts to secure a partner for the project.

Northern Dynasty does not have any operating revenue, although currently and historically it has had non-material annual interest revenue as a consequence of investing its surplus funds and has received consideration for the sale of a net proceeds interest royalty held on a non-core property that was carried at nominal value.

Three Year History

CWA 404 Permit Application

The Pebble Partnership submitted a CWA Section 404 Permit Application for the Pebble Project to the USACE in December 2017 and the federal permitting process was initiated in January 2018. The final EIS was issued in July 2020, following intensive review. The final EIS was viewed by the Company as positive in that it found impacts to fish and wildlife would not be expected to affect harvest levels, there would be no measurable change to the commercial fishing industry including prices and there would be positive socioeconomic impacts on local communities. Nevertheless, in November 2020, the USACE announced a negative ROD.

The Pebble EIS permitting process involved the Pebble Partnership being actively engaged with the USACE on the evaluation of the Pebble Project. There were numerous meetings between representatives of the USACE and the Pebble Partnership regarding, among other things, compensatory mitigation for the Pebble Project. For further details on the CMP see the Company’s 2022 AIF. The Pebble Partnership submitted its request for appeal of the ROD (the "RFA") to the USACE Pacific Division on January 19, 2021. The RFA reflects the Pebble Partnership’s position that the USACE's Record of Decision and permitting decision – including its “significant degradation” finding, its ‘public interest review' findings, and its perfunctory rejection of the Pebble Partnership's CMP – are contrary to law, unprecedented in Alaska, and fundamentally unsupported by the administrative record, including the Pebble EIS. The specific reasons for appeal asserted by the Pebble Partnership in the RFA include (i) the finding of “significant degradation” by the USACE is contrary to law and unsupported by the record, (ii) the USACE’s rejection of the compensatory mitigation plan is contrary to the USACE regulations and guidance, including the failure to provide the Pebble Partnership with an opportunity to correct the alleged deficiencies, and (iii) the determination by the USACE that the Pebble Project is not in the public interest is contrary to law and unsupported by the public record.

In a letter dated February 24, 2021, the USACE confirmed the Pebble Partnership’s RFA is “complete and meets the criteria for appeal.” The USACE completed the administrative record for the appeal and provided a copy to the Pebble Partnership in June 2021, following which the Pebble Partnership and its legal counsel reviewed the voluminous record for completeness and relevance to the USACE’s permitting decision, and its sufficiency to support a fair, transparent and efficient review. In August 2021, the USACE also informed the Pebble Partnership that a new Review Officer ("RO") had been appointed to lead the Pebble Project appeal. An appeal conference was held in July 2022. The USACE Pacific Ocean Division issued its Administrative Appeal Decision on April 25, 2023. That decision did not sustain the permit denial decision on the Pebble Project that was originally made by the Alaska District, and instead remanded the matter back to the Alaska District to re-evaluate specific issues. The Administrative Appeal Decision set forth the RO’s assessment of the merits of the Pebble Partnership’s reasons for appeal, as set forth in the RFA. The decision found that certain key reasons for appeal had merit, while other arguments did not have merit. As a result, the USACE ordered that the ROD be remanded to the Alaska District Engineer for reconsideration, additional evaluation, and documentation sufficient to support the decisions. Key elements of the decision included the following:

In light of the Final Determination (see EPA Proposed and Final Determinations under the CWA below) and the remand decision, the District was instructed to review the appeal decision and had 45 days to notify the parties how it plans to proceed.  Six extensions were requested and granted, including on November 27, 2023, when the Division Commander approved the request for an extension until the Supreme Court acts on the State of Alaska’s bill of complaint challenging the EPA’s exercise of its CWA Section 404(c) authority.  On January 8, 2024, the Supreme Court announced they would not hear the State’s complaint directly and it would have to go through the normal Federal Court process.  As of March 2024, the Division Commander had not acted on this decision, but has informed the Company that it will provide an update on its decision, but with no specific timeline for that response.

With respect to the Final Determination issued by the EPA, however, the USACE cannot issue a permit under the CWA at this time even if the Pebble Partnership is successful in submitting a CMP that is acceptable to the USACE. Accordingly, there is no assurance that this remand and further CMP process will ultimately result in the issuance of a positive ROD by the Alaska District. If this remand does not result in the issuance of a positive ROD, the Company may seek judicial review of the ROD in the appropriate U.S. District Court. There is no assurance that any judicial review would be successful in overturning the ROD.

EPA Proposed and Final Determinations under the CWA

In February 2014, the EPA announced a pre-emptive regulatory action under Section 404(c) of the CWA to consider restriction or a prohibition of mining activities associated with the Pebble Deposit, referred to as the Original Proposed Determination. From 2014-2017, Northern Dynasty and the Pebble Partnership focused on a multi-dimensional strategy, including legal and other initiatives to ward off the Original Proposed Determination. These efforts were successful, resulting in the joint settlement agreement announced on May 12, 2017, enabling the Pebble Project to move forward with state and federal permitting. As part of the joint settlement agreement, the EPA agreed to initiate a process that led to the withdrawal of the Original Proposed Determination in July 2019.

On September 9, 2021, the EPA announced it planned to re-initiate its Revised Proposed Determination process of making a CWA Section 404(c) determination for the waters of Bristol Bay, which would set aside the 2019 withdrawal of the Original Proposed Determination that was based on a 2017 settlement agreement between the EPA and Pebble Partnership. The Company believes the results of the Pebble EIS support the 2019 withdrawal. As part of its review process, the EPA issued a letter dated January 27, 2022, to the Pebble Partnership advising as to the EPA’s belief that the discharge of dredged or fill associated with mining of the Pebble Project could result in unacceptable adverse effects on important fishery areas and of its intent to issue a Revised Proposed Determination. The EPA’s letter was also addressed to the USACE and the State of Alaska Department of Natural Resources. The EPA invited the Pebble Partnership, the USACE, and the State of Alaska Department of Natural Resources to submit information “to demonstrate that no unacceptable adverse effects to aquatic resources” would result from the Pebble Project. The Pebble Partnership responded to the EPA on March 28, 2022 contesting both the factual claim by the EPA as to the impact on aquatic resources and the legal basis on which the EPA has proposed to act.

On May 25, 2022, the EPA announced its intent to advance its pre-emptive veto of the Pebble Project and issued its Revised Proposed Determination. The Revised Proposed Determination would establish a "defined area for prohibition" coextensive with the current mine plan footprint in which the EPA would prohibit the disposal of dredged or fill material for the Pebble Project. The Revised Proposed Determination would also establish a 309-square-mile "defined area for restriction." Public comments on the Revised Proposed Determination were due on September 6, 2022. In September 2022, the Pebble Partnership submitted extensive comments on the Revised Proposed Determination, objecting to the EPA’s preemptive veto of the Pebble Project. The Pebble Partnership called upon the EPA to withdraw its action and refrain from further action against the project. A compelling letter and comments by the State of Alaska and a second letter signed by a total of 14 states were also submitted to the EPA, protesting against the EPA’s overreach with the Revised Proposed Determination.

On January 30, 2023, the EPA issued the Final Determination under Section 404(c) of the CWA, imposing limitations on the use of certain waters in the Bristol Bay watershed as disposal sites for certain discharges of dredged or fill material associated with development of a mine at the Pebble deposit. The Final Determination is the concluding step in the administrative process set forth in 40 C.F.R. Part 231, which governs EPA’s authority under Section 404(c) to veto permit decisions. The Administrative Procedure Act ("APA"), 5 USC §551 et seq., which governs judicial review of agency decisions, provides that individuals aggrieved by agency action may seek judicial review of any "final agency action." The EPA’s administrative determination can be challenged by filing a lawsuit in U.S. federal district court seeking reversal of that decision.

The Final Determination includes the determinations of the EPA that:

Based on these determinations, the Final Determination:

On July 26, 2023, the State of Alaska filed a Motion for Leave to File a Bill of Complaint with the United States Supreme Court challenging the Final Determination.  In their complaint they asked the Supreme Court to hear their case, bypassing the typical process of going through the Federal District Court system first. On January 8, 2024, the U.S. Supreme Court announced they would not hear the State’s complaint directly and it would have to go through the normal Federal Court process, meaning that the complaint would first have to be heard by a federal district court and then by a federal circuit court of appeal before being considered by the Supreme Court.

The Company and Pebble Partnership are seeking judicial review of the Final Determination.  In March 2024, the Company and Pebble Partnership filed two separate actions in the federal courts challenging the federal government’s actions to prevent the Company and the Pebble Partnership from building a mine at the Pebble Project.

One action, filed in Federal District Court in Alaska seeks to vacate the EPA’s Final Determination to veto a development at Pebble. This is the main focus of the legal actions. The complaint in this action alleges, among many other points:

An action was also filed in the United States Court of Federal Claims in Washington, DC claiming that the actions by the EPA constitute an unconstitutional “taking” of Northern Dynasty’s and the Pebble Partnership’s property. We plan to ask the court to defer considering this action until the EPA veto case, discussed in Action 1 above, has been finally resolved.  Our permitting strategy is focused entirely on winning the EPA veto case and permitting the Pebble project.  The “takings” case is a secondary strategy only, and the filing of the “takings” case at this time ensures that we would not be barred from doing so by the statute of limitations in the future.

On March 14, 2024, the State of Alaska filed a “takings” action in the United States Court of Federal Claims in Washington, DC. It is anticipated that the State of Alaska will also be filing an action in Federal District Court in Alaska that is similar to that filed by us.

There is no assurance that ether of our legal actions to challenge the Final Determination will be successful in overturning the Final Determination or securing financial damages in our favour. In addition, there is no assurance that the Pebble Partnership’s appeal of the ROD will be successful.  If not withdrawn or overturned, the Final Determination would prevent the Company from developing the Pebble deposit as set out in the 2020 Project Plan or in any other mine plan that the EPA would consider as resulting in "adverse effects similar or greater in nature and magnitude to the adverse effects of the 2020 Project Plan”.

Much of the work by the Company through the Pebble Partnership from 2017 to 2023 has focused on facilitating and providing support to the federal EIS permitting process and subsequent appeal. The Company has also continued to actively engage and consult with project stakeholders to share information and gather feedback on the Pebble Project, its potential effects and proposed mitigation. In 2018, 2019 and 2020, the Company also secured right-of-way agreements with Alaska Native village corporations and other landowners whose lands cover portions of several proposed transportation and infrastructure routes for the Pebble Project. Opportunities for additional community benefits from development of the project were also explored, including the Pebble Performance Dividend revenue sharing program for full-time adult residents of Bristol Bay communities, and a Memorandum of Understanding with Alaska Peninsula Corporation announced in July 2020. The Company’s technical team has overseen engineering studies to support the development of a Preliminary Economic Assessment of the Pebble Project as well as carrying out monitoring and maintenance programs at the Pebble site. An active corporate presence has been maintained in Alaska and Washington, D.C., to engage and consult with government and project stakeholders.

Independent Preliminary Economic Assessment

In September 2023, the Company announced the results of an independent Preliminary Economic Assessment of the Pebble Project, effective date August 21, 2023 ("2023 PEA"). The report is an independent review of the project that provides updated cost and price estimates to reflect current economic volatility. It includes an infrastructure plan that uses the “southern route” for project access as defined in the original permitting application for the Pebble Project. The 2023 PEA also updates the status of the EPA’s Final Determination and USACE Record of Decision Appeal processes to that time.

The 2023 PEA provides production, financial and cost estimates for a proposed 20-year, 180,000 tons per day open pit operation with conventional processing producing three concentrates for the Pebble Project in Southwest Alaska (the “Proposed Project”) as described in the Pebble Project permit application and its amendments. The study presents positive projected financial results, excellent optionality and important benefits for Alaska from the potential mine development at Pebble.

The 2023 PEA also examines potential mine expansion scenarios1, which are presented to test the sensitivity of the project to such expansions and to demonstrate the optionality inherent in the polymetallic Pebble deposit by presenting a possible pathway for future mine development; in addition, it assesses the potential future addition of a secondary recovery gold plant. These sensitivity analyses indicate the project life could be extended for periods of up to a century to extract slightly more than 70% of the mineral resource, with commensurate increases in metal production and potentially, improved financial results.

For further details on the 2023 PEA, see Description of Business.

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1 The project as originally designed in 2017 and subsequently amended during the EIS NEPA process (the "2020 Project Plan) would extract slightly more than 10% of the currently estimated Pebble mineral resource.  This does not preclude development of additional resources in other phases of the project in the future, although any subsequent phases of development would require extensive regulatory and permitting review by federal, state and local regulatory agencies, including a further comprehensive EIS review process under NEPA.  During the NEPA process, the Pebble Partnership received a Request for Information ("RFI") from the USACE for a conceptual mine layout and written description of an expansion phase beyond the 2020 Project Plan.  The Pebble Partnership submitted a conceptual project mine plan layout and written description to the USACE, which described a case that would expand to 250,000 tons per day in Year 21.  The Pebble Partnership further explained that the “concept is merely one of several expanded development scenarios that could potentially be proposed and permitted in the future.”  The Pebble Partnership response to the RFI and this response is part of the EIS Administrative Record.  The 2023 PEA tests the sensitivity of the project to such an expansion by evaluating three potential expansions: one was that envisioned in the RFI response, the other two would see the project expand to 270,000 tons per day in Year 5 or in Year 10. 

Corporate Activities and Financing

Corporate activities were directed toward corporate reporting, investor relations and discussions directed toward securing a partner with which to advance the overall development of the project. Northern Dynasty has completed the following financings and/or raised funds within the past three years to fund its business operations:

Item 5. Description of Business

A. The Pebble Project

The Company’s business is the exploration and advancement towards feasibility, permitting and ultimately development of the Pebble Project.

The Pebble Project Is Subject To State and Federal Laws

The Pebble Partnership and its subsidiaries are required to comply with all Alaska statutes in connection with the Pebble Project. These statutes govern titles, operations, environmental, development, and generally all aspects of exploration, development and operation of a mine in Alaska.

Alaska Statute 38.05.185, among others, establishes the rights to mining claims and mineral leases on lands owned by the State of Alaska and open to mineral entry. This group of statutes also cover annual labor and rental requirements, and royalties.

Operations on claims or leases on state owned land must be permitted under a plan of operations as set out in Title 11 of the Alaska Administrative Code, Chapter 86, Section 800. This regulation generally provides that the State Division of Mining can be the lead agency in coordinating the comments of all agencies which must consent to the issuance of a plan of operations, and sets the requirements for the approval of a plan of operations.

Environmental conditions are controlled by Alaska Statute 46.08 (which prohibits release of oil and hazardous substances), Alaska Statute 46.03.060 (which sets water quality standards), and Alaska Statute 46.14 (which sets air quality standards).

Once a decision is made to enter permitting, the Pebble Project will be required to satisfy permitting requirements at three levels: federal, state and local (borough). The process takes approximately 3-4 years to complete and involves 11 regulatory agencies, 60+ categories of permits and significant ongoing opportunities for public involvement. The Alaska Department of Natural Resources Large Mine Permitting Team is responsible for coordinating permitting activities for large mine projects.

To satisfy permitting requirements under NEPA and other regulatory statutes, a project must provide a comprehensive project design and operating plan for mine-site and infrastructure facilities; documentation of development alternatives investigated; mitigation and compensation strategies, and identification of residual effects; and environmental monitoring, reclamation and closure plans. The first step is to provide the required information (including a Project Description and Environmental Baseline Document) for an EIS under NEPA, prepared by a third-party contractor under the direction of a lead federal agency. The EIS determines whether sufficient evaluation of the project's environmental effects and development alternatives has been undertaken. It also provides the basis for federal, state and local government agencies to make individual permitting decisions.

Under the CWA, Section 404(c), the Administrator of the EPA is given the right to disallow the specification (including the withdrawal of specification) of any defined area as a disposal site if he or she determines that the release of material at the disposal site will have an unacceptable adverse effect on municipal water supplies, local wildlife, spawning and breeding areas of fisheries, shellfish beds, and/or recreational areas. Such decisions made by the Administrator require notice and opportunity for public hearings, and consultation with the Secretary of the Army. The Administrator shall set forth in writing and make public his or her findings and reasons for making any determination under this subsection.

B. Technical Summary

The following disclosure is based on the document entitled, Pebble Project, NI 43-101 Technical Report Update and Preliminary Economic Assessment, Alaska, United States of America, effective date August 21, 2023 by Robin Kalanchey, P.Eng., Ausenco Engineering Canada Inc., Scott Weston, P.Geo., Ausenco Sustainability Inc., Graeme Roper, P.Geo., Tetra Tech Canada Inc., Greg Z. Mosher, P.Geo., Tetra Tech Canada Inc., Hassan Ghaffari, P.Eng., Tetra Tech Canada Inc., Sabry Abdel Hafez, PhD, P.Eng., Worley Canada Services Ltd., Les Galbraith, P.Eng., P.E., Knight Piésold Ltd., Stuart J. Parks, P.E., NANA Worley, James Wescott Bott, P.E., HDR Alaska Inc. and Steven R. Rowland, P.E., RECON LLC. All are qualified persons who are independent of Northern Dynasty.

The 2023 PEA is filed under the Company’s profile in Canada on Sedarplus at www.sedarplus.ca and in the U.S. on EDGAR at www.sec.gov.

All currency numbers in this section are in US Dollars.

Project Description and Location

Location

The Pebble deposit is located in southwest Alaska, approximately 200 miles southwest of Anchorage, 17 miles northwest of the village of Iliamna, 100 miles northeast of Bristol Bay, and 60 mi west of Cook Inlet (Figure 1).

Figure 1 – Location

Source: 2023 PEA

Mineral Tenure

Northern Dynasty holds indirectly through Pebble East Claims Corporation and Pebble West Claims Corporation, wholly owned subsidiaries of the wholly owned Pebble Partnership, a 100% interest in a contiguous block of 1,840 administratively active mining claims and leasehold locations covering 274 square miles (which includes the Pebble deposit).

State mineral claims in Alaska are kept in good standing by performing annual assessment work or in lieu of assessment work by paying $100 per year per 40 acre (0.06 square miles) mineral claim, and by paying annual escalating State rental fees each year. Assessment work is due annually by noon of September 1.  However, credit for excess assessment work can be banked for a maximum of four years after the work is performed and can be applied as necessary to continue to hold the claims in good standing. Annual assessment work obligations for the 1,840 project claims total $442,900 and are due each year on September 1.  The 2023 annual Affidavit of Labor on the claims was registered with the Alaska Department of Natural Resources (ADNR) on August 28, 2023.  Annual State rentals for 2023 were $912,880 and were paid on November 28, 20232.

The details of the administratively active mining claims and leasehold locations are provided in the 2023 PEA.

The claim boundaries have not been surveyed.

Royalties and Other Agreements

Northern Dynasty does not own any surface rights associated with the Pebble property mineral claims. All mineral claims are on lands held by the State of Alaska and surface rights may be acquired from the state once areas required for mine development have been determined and permits awarded.

_____________________ 

2 Information has been updated based on the 2023 filings completed since the 2023 PEA.  

Both the access corridor north of Iliamna Lake as defined by the least environmentally destructive practicable alternative (“LEDPA”) in the Final Environmental Impact Statement (“FEIS”) and the originally proposed corridor crossing Iliamna Lake are owned by a number of landowners, including the State of Alaska, Alaska Native village corporations, and private individuals. Pebble Partnership has completed access agreements with two Native village corporations and a private individual. Under the terms of these agreements, the Native village corporations could receive significant sums over the life of the mine. Negotiations have advanced with other Native village corporations and individuals, but no agreements are in place. In June 2021, Pedro Bay Corporation (“PBC”) announced they had signed an agreement whereby a fund has obtained an option to buy portions of their land to create a conservation easement. PBC and the fund announced the exercise of the option in December 2022. While the Pebble Partnership has not explored the full range of options available to it with this announcement, its current assumption is the route defined in the June 2020 FEIS is no longer practicable and thus does not qualify as the LEDPA. Accordingly, the Pebble Partnership is analysing the amended version of the southern alternative originally proposed for the transportation route.

A portion of the mineral claims (Exploration Lands shown in Figure 2) are subject to a net profits interest (NPI) royalty payable to Teck Resources Limited (“Teck”). However, the portion of the deposit to be mined by the proposed project lies outside the portion subject to the NPI and is therefore not subject to the Teck royalty. The project is subject to a State of Alaska royalty.3

Figure 2 – Property and Location of Exploration Lands, Resource Lands and Pebble Deposit

Source: 2023 PEA

In July 2022, the Pebble Partnership entered into a Royalty Agreement whereby the royalty holder has the right to receive a portion of the gold and silver production from the proposed Pebble Project for the life of the mine. The royalty holder has the option to acquire up to 10% of the payable gold production and up to 30% of the payable silver production, in five separate tranches of $12 M, each. The payment for the first tranche has been received by the Pebble Partnership with the royalty holder having the option to increase its interest over the next two years. Each tranche entitles the royalty holder to 2% of the payable gold production and 6% of the payable silver production, after accounting for a notional payment by the royalty holder of $1,500 per ounce of gold and $10 per ounce of silver, respectively, for the life of the mine. The Pebble Partnership will share in 20% of excess prices above $4,000 per ounce for gold and $50 per ounce for silver and will retain a portion of the metal produced for recovery rates in excess of 60% for gold and 65% for silver. Both the payment of the first tranche and all five tranches are shown in the report to demonstrate the impact of the royalty at the first tranche and full payment levels.

___________________ 

3 Teck holds a 4% pre-payback net profits interest (after debt service), followed by a 5% after-payback net profits interest in any mine production from the Exploration Lands shown in Figure 2.  These considerations have been included in the financial analysis of the Potential Expansion Scenarios, presented under Project Development - Sensitivity Analysis.

The Pebble Performance Dividend LLP will distribute a 3% net profits royalty interest in the project to adult residents of Bristol Bay villages that have subscribed as participants. The Pebble Performance Dividend will distribute a guaranteed minimum annual payment of US$3 M each year the Pebble mine operates beginning at the outset of construction. Total life-of-mine payments for the proposed project could total $190 M and could range as high as almost $3.9 B for the life of mine estimated in selected potential expansion scenarios which include a gold plant.

The Pebble property is within the Lake and Peninsula Borough and is subject to a 1.5% severance tax. The life-of-mine severance tax payments for the proposed project could total $530 M and range as high as $5.1 B for the life of mine estimated in selected potential expansion scenarios which include a gold plant.

Accordingly, the project could potentially provide more than $9.1 B to the Southwest Alaska region through the Pebble Performance Dividend and the Lake and Peninsula Borough severance tax over the life of mine that may be achieved in some of the potential expansion scenarios. This is in addition to the other significant benefits that could flow from the existing and possible future agreements with Alaska Native village corporations.

Environmental Liabilities

The Pebble Partnership currently maintains 471 monitoring wells that are periodically used to collect piezometric and water quality data across the project area. The Pebble Partnership did retain a small year-round field facility and two satellite facilities at the deposit site to store materials and equipment used to support maintenance activities. However, most of these facilities were destroyed in a regional tundra fire that swept through the deposit area during the summer of 2022. The Pebble Partnership removed most of the damaged material from the fire aftermath in September 2022 and will revisit the site in 2024 to complete collection any remaining minor debris such as bolts and screws with magnetic rollers. The environmental liabilities associated with the Pebble Project include completion of the fire cleanup, removal of any additional remaining temporary structures and field equipment, closure of monitoring wells, and removal of piezometers. The State of Alaska holds a $2 M reclamation security associated with removal and reclamation of these liabilities.

Permitting

Permits necessary for exploration drilling and other field programs associated with pre-development assessment of the Pebble Project are applied for as required each year.  

On December 22, 2017, the Pebble Partnership submitted its permit application under the CWA and the Rivers and Harbors Act (RHA). The project description in the permit application envisaged the Pebble deposit would be developed as an open pit mine with associated on and off-site infrastructure. Over the course of the subsequent 30 months, additional engineering work completed to support the environmental assessment process, as well as recommendations from the USACE in the FEIS, resulted in modifications to the plan and the project description was updated accordingly. The proposed project as described in the 2023 PEA corresponds to the project description issued with the June 2020 Revised Project Application, which is attached to the FEIS. Project infrastructure includes the following:

Proposed access to the project and relating offsite infrastructure are presented on Figure 3, and the mine site layout is shown in Figure 4.

Figure 3 – Access and Proposed Infrastructure

Source: 2023 PEA

Figure 4 - Mine Site Layout

Source: 2023 PEA

Figure prepared by Knight Piésold, 2020

Following an estimated 4.5 years of construction activity, the proposed project would operate for 20 years, with conventional drill-and-blast shovel-truck operations in an open pit feeding a conventional copper porphyry flotation process plant. The mining rate would average 70 million tons per year, with 66 million tons of mineralized material processed through the process plant each year (180,000 tons per day), for a low life-of-mine strip ratio of waste to mineralized material of 0.12:1.

The development proposed in Pebble Limited Partnership’s project description is substantially smaller than that envisioned in a 2011 Technical Report (Ghaffari et al, 2011), and presents significant new environmental safeguards, including the following:

The development plan outlined in the proposed project uses a portion of the currently estimated Pebble mineral resources. This does not preclude future development of additional resources, but such development would require additional evaluation and would be subject to separate permitting processes.

The Pebble Project consists of a number of components at the mine site, including the open pit mine, process plant, tailings and water management facilities, and other support facilities, and transportation and power supply infrastructure. These components as described in the 2023 PEA collectively constitute the project submitted by Pebble Partnership for CWA permitting in 2017 and subsequently amended during the process and are thus entitled the Proposed Project. This Proposed Project is described in the amended Project Description dated December 12, 2019. Capital and operating costs are estimated in the 2023 PEA for the Proposed Project. It is common in Alaska and elsewhere for third parties to participate in the development of the project through provision of infrastructure for which the project pays lease or usage fees. For example, the transportation infrastructure for the Red Dog Mine in Alaska is owned by the Alaska Industrial Development and Export Authority (AIDEA). AIDEA is also the proponent for a major transportation route in northern Alaska which would support the Arctic project. Such a scenario was developed for the Pebble Project and because it is the likely route to development, it is the Base Case.

In November 2020, USACE issued its Record of Decision (ROD) denying Pebble Partnership’s application. The Pebble Partnership submitted a request for appeal (RFA), which was accepted by USACE in February 2021 and on April 25, 2023, the USACE Pacific Ocean Division remanded the decision back to the USACE Alaska District to re-evaluate specific issues. For information on the current status of the remand see Three Year History.

On September 9, 2021, the EPA announced it planned to re-initiate the process of making a CWA Section 404(c) determination for the waters of Bristol Bay. The EPA published a Final Determination on January 30, 2023, that establishes a “defined area for prohibition” coextensive with the current mine plan footprint in which the disposal of dredged or fill material would be prohibited for the Pebble Project. The Final Determination also establishes a 309-square-mile “defined area for restriction” that encompasses the area of the Pebble Project. Under the terms of the Final Determination, the proposed project could not proceed. The Pebble Partnership has challenged the Final Determination (see Three Year History for current status) but there is no assurance that its challenge will be successful.

Accessibility, Climate, Local Resources, Infrastructure and Physiography

Access

Access to the project is typically via air from the city of Anchorage to the airport serving the villages of Iliamna and Newhalen. With 292,000 residents, Anchorage is the largest city in Alaska. It is situated at the northeastern end of Cook Inlet and is connected to the national road network via Interstate Highway 1 through Canada to the USA. Anchorage is serviced daily by numerous regularly scheduled flights to major airport hubs in the USA.

From Anchorage, there are regular flights to Iliamna through Iliamna Air Taxi and other operators. Charter flights may also be arranged from Anchorage. From Iliamna, current access to the Pebble Site is by helicopter.

Climate

The climate of the project area is transitional; it is more continental in winter because of frozen water bodies and more maritime in summer because of the influence of the open water of Iliamna Lake and, to a lesser extent, the Bering Sea and Cook Inlet. Mean monthly temperatures in the deposit area range from 11.4°F in January to 50.8°F in July (at the Pebble 1 meteorological station). The mean annual precipitation in the deposit area is estimated to be 54.6 inches (at the Pebble 1 meteorological station). One-third of this precipitation falls as snow. The wettest months are August through October.

The climate is sufficiently moderate to allow a well-planned mineral exploration program could be conducted year-round (Rebagliati, C.M., and Haslinger, R.J., 2003) at Pebble, although the programs were typically restricted over the winter because of the shorter daylight and weather conditions. The Pebble Project will operate year-round, although transportation operations may experience short-term weather-related delays.

Infrastructure

There is a modern airfield at Iliamna, with two paved 4,920 ft airstrips, that services the communities of Iliamna and Newhalen. The runways are suitable for DC-6 and Hercules cargo aircraft and for commercial jet aircraft.

There are paved roads that connect the villages of Iliamna and Newhalen to the airport and to each other and a partly paved, partly gravel road that extends to a proposed Newhalen River crossing near Nondalton. The Pebble Site is currently not connected to any of these local communities by road; a road would be planned as part of the project design.

There is no access road that connects the communities nearest the Pebble Site to the coast on Cook Inlet. From the coast, at Williamsport on Iliamna Bay, there is an 18.6-mile state-maintained road that terminates at the east end of Iliamna Lake, where watercraft and transport barges may be used to access Iliamna. The route from Williamsport, overland to Pile Bay on Iliamna Lake, is currently used to transport bulk fuel, equipment and supplies to communities around the lake during the summer months.

Also, during summer, supplies have been barged up the Kvichak River, 43.4 mi southwest of Iliamna, from Kvichak Bay on the North Pacific Ocean.

A small run-of-river hydroelectric installation on the nearby Tazamina River provides power for the three communities in the summer months. Supplemental power generation using diesel generators is required during winter months.

Local Resources

Iliamna and surrounding communities have a combined population of just over 400 people. As such, there is limited local commercial infrastructure except that which services seasonal sports fishing and hunting.

Details on the availability of power, water, mining personnel, and planned locations for key infrastructure for the project that is envisaged is further described in the 2023 PEA.

Physiography

The Pebble site area is located in the Nushagak-Big River Hills physiographic region. The area consists of low, rolling hills separated by wide, shallow valleys. Elevations range from 775 ft in the South Fork Koktuli (SFK) valley up to 2,760 ft on Kaskanak Mountain. Glacial and fluvial sediment of varying thickness covers most of the study area at elevations below 1,400 ft, whereas the ridges and hills above 1,400 ft generally exhibit exposed bedrock or have thin veneers of surficial material. The hills tend to be moderately sloped with rounded tops. The valley bottoms are generally flat. No permafrost has been identified to date in the project area.

History

Cominco Alaska, a division of Cominco Ltd. (now Teck), began reconnaissance exploration in the Pebble region in the mid-1980s, and in 1984 discovered the Sharp Mountain gold prospect near the southern margin of the current property. Teck staked their first mineral claims on the property during reconnaissance mapping and sampling programs in the Cone and Sharp Mountain areas in August and September 1984. In November 1987, Teck staked claims on the newly discovered Sill and Pebble prospects and added claims to these two areas in July 1988. This staking, along with additional claims added in the 1990s, led to the formation of a large continuous claim group. Teck completed a two-part purchase option with Hunter Dickinson Group Inc. (HDGI), which in turn assigned 80% of that option to Northern Dynasty in October 2001.

The first part of the option agreement covered that portion of the property which had previously been drilled and on which the majority of the then known copper mineralization occurred (the Resource Lands Option) and the remaining area outside the Resource Lands (the Exploration Lands). In November 2004, Northern Dynasty exercised the Resource Lands Option and acquired 80% of the resource lands. In February 2005, Teck elected to sell its residual 50% interest in the Exploration Lands to Northern Dynasty for US$4 million. Teck still retains a 4% pre-payback advance net profits royalty interest (after debt service) and 5% after-payback net profits interest royalty in any mine production from the Exploration Lands portion of the Pebble property.

In June 2006, Northern Dynasty acquired, through its Alaska subsidiaries, the remaining HDGI 20% interest in the Resource Lands and Exploration Lands by acquiring HDGI from its shareholders and through its various subsidiaries had thereby acquired an aggregate 100% interest in the Pebble property, subject only to the Teck net-profits royalties on the Exploration Lands.

In July 2007, the Pebble Partnership was created and an indirectly wholly owned subsidiary of Anglo-American plc (Anglo American) subscribed for 50% of the Pebble Partnership's equity effective July 31, 2007.  In December 2013, Northern Dynasty exercised its right to acquire Anglo American’s interest in the Pebble Partnership and now holds a 100% interest.

On June 29, 2010, Northern Dynasty entered into an agreement with Liberty Star Uranium and Metals Corp. and its subsidiary, Big Chunk Corp. (together, Liberty Star), pursuant to which Liberty Star sold 23.8 square miles of claims (the 95 purchased claims) to a U.S. subsidiary of Northern Dynasty in consideration for both a US$1 M cash payment and a secured convertible loan from Northern Dynasty in the amount of US$3 M.  Northern Dynasty later agreed to accept transfer of 199 claims (the Settlement Claims) located north of the ground after held 100% by the Pebble Partnership in settlement of the loan, and subsequently both the Purchased Claims and the Settlement Claims were transferred to a Northern Dynasty subsidiary and ultimately to Pebble West Claims Corporation, a subsidiary of the Pebble Partnership.

On January 31, 2012, the Pebble Partnership entered into a Limited Liability Company Agreement with Full Metal Minerals (USA) Inc. (FMMUSA), a wholly owned subsidiary of Full Metal Minerals Corp., to form Kaskanak Copper LLC.  On May 8, 2013, the Pebble Partnership purchased FMMUSA’s ownership interest in the LLC for a cash consideration of US$750,000.  As a result, the Pebble Partnership gained a 100% ownership interest in the LLC, the indirect owner of a 100% interest in a group of 464 claims located south and west of other ground held by the Pebble Partnership.  In 2014 the LLC was merged into Pebble East Claims Corporation, a subsidiary of the Pebble Partnership, which now holds title to these claims. 

On December 15, 2017, Northern Dynasty entered into a framework agreement with First Quantum Minerals Ltd. (First Quantum) which contemplated that an affiliate of First Quantum would subsequently execute an option agreement with Northern Dynasty with an option payment of US$150 M staged over four years.  This option would entitle First Quantum to acquire the right to earn a 50% interest in the Pebble Partnership for US$1.35 B.  First Quantum made an early option payment of US$37.5 M to Northern Dynasty, applied solely for the purposes of progressing the permitting of the proposed project, but withdrew from the project in 2018. 

Geological Setting, Mineralization and Deposit Type

Pebble is a porphyry-style copper-gold-molybdenum-silver-rhenium deposit that comprises the Pebble East and Pebble West zones of equal size, with slightly lower-grade mineralization in the center of the deposit where the two zones merge. The Pebble deposit is located at the intersection of crustal-scale structures that are oriented both parallel and obliquely to a magmatic arc which was active in the mid-Cretaceous and which developed in response to the northward subduction of the Pacific Plate beneath the Wrangellia Superterrane.

The oldest rock within the Pebble district is the Jurassic-Cretaceous age Kahiltna flysch, composed of turbiditic clastic sedimentary rocks, interbedded basalt flows and associated gabbro intrusions. During the mid-Cretaceous (99 to 96 Ma), the Kahiltna assemblage was intruded first by coeval granodiorite and diorite sills and slightly later by alkalic monzonite intrusions. At 90 Ma, hornblende diorite porphyry plutons of the Kaskanak batholith were emplaced. Copper-gold-molybdenum-silver-rhenium mineralization is related to smaller granodiorite plutons and dykes that are similar in composition to, and emplaced near and above the margins of, the Kaskanak batholith.

The Pebble East and Pebble West zones are coeval hydrothermal centers within a single magmatic-hydrothermal system. The movement of mineralizing fluids was constrained by a broadly vertical fracture system acting in conjunction with a hornfels aquitard that induced extensive lateral fluid migration. The large size of the deposit, as well as variations in metal grade and ratios, may be the result of multiple stages of metal introduction and redistribution.

Mineralization in the Pebble West zone extends from surface to 3,000 ft deep and is centered on four small granodiorite plutons. Mineralization is hosted by flysch, diorite and granodiorite sills, and alkalic intrusions and breccias. The Pebble East zone is of higher grade and extends to a depth of at least 5,810 ft; mineralization on the eastern side of the zone was later dropped 1,970 to 2,950 ft by normal faults which bound the northeast-trending East Graben. The Pebble East zone mineralization is hosted by granodiorite plutons and dykes, and by adjacent granodiorite sills and flysch. The Pebble East and West zone granodiorite plutons merge at depth.

Mineralization at Pebble is predominantly hypogene, although the Pebble West zone contains a thin zone of variably developed supergene mineralization overlain by a thin leached cap. Disseminated and vein-hosted copper-gold-molybdenum-silver-rhenium mineralization, dominated by chalcopyrite and locally accompanied by bornite, is associated with early potassic alteration in the shallow part of the Pebble East zone and with early sodic-potassic alteration in the Pebble West zone and deeper portions of the Pebble East zone. Rhenium occurs in molybdenite and high rhenium concentrations are present in molybdenite concentrates. Elevated palladium concentrations occur in many parts of the deposit but are highest in rocks affected by advanced argillic alteration. High-grade copper-gold mineralization also is associated with younger advanced argillic alteration that overprinted potassic and sodic-potassic alteration and was controlled by a syn-hydrothermal, brittle-ductile fault zone located near the eastern margin of the Pebble East zone. Late quartz veins introduced additional molybdenum into several parts of the deposit.

Exploration

Geological, geochemical, and geophysical surveys were conducted in the project area from 2001 to 2007 by Northern Dynasty and since mid-2007 by the Pebble Partnership.

Geological mapping for rock type, structure, and alteration was carried out between 2001 and 2006 over the entire project area. This work provided an important geological framework for interpretation of other exploration data and drilling programs.

Geophysical surveys were completed between 2001 and 2010. In 2001, dipole-dipole IP surveys totaling 19.3 line-mi were completed by Zonge Geosciences for Northern Dynasty, following up on and augmenting similar surveys completed by Teck. During 2002, a ground magnetometer survey totaling 11.6 line-mi was completed at Pebble. The principal objective of this survey was to obtain a higher resolution map of magnetic patterns than was available from existing regional government magnetic maps. During 2007, a limited magnetotelluric survey was completed by GSY-USA Inc., under the supervision of Northern Dynasty geologists. The survey focused on the area of drilling in the Pebble East zone and comprised 196 stations on nine east-west lines and one north-south line, at a nominal station spacing of 656 ft. In July 2009, Spectrem Air Limited completed an airborne electromagnetic, magnetic and radiometric survey over the Pebble area. The objectives of this work included providing geophysical constraints for structural and geological interpretation in areas with significant glacial cover. Between the second half of 2009 and mid-2010, 120.5 line-mi of IP chargeability and resistivity data were collected by Zonge Engineering and Research Organization Inc. The objective of this survey was to extend the area of IP coverage completed prior to 2001 by Teck and during 2001 by Northern Dynasty. During 2010, an airborne electromagnetic (EM) and magnetometer geophysical survey was completed on the Pebble property totaling 4,009 line-mi.

Geochemical surveys were completed between 2001 and 2012. Between 2001 and 2003, Northern Dynasty collected 1,026 soil samples (Rebagliati and Lang, 2009). Samples were more widely spaced near the north, west, and southwest margins of the grid. Three very limited surficial geochemical surveys were completed by the Pebble Partnership in 2010 and 2011; no significant geochemical anomalies were identified. A total of 126 samples, comprising 113 till and 13 soil samples, were collected on the KAS claims located in the southern end of the property; samples were on lines spaced 8,000 ft apart with a sample spacing of 1,300 ft. Additional surveys were completed between 2007 and 2012 by researchers from the USGS and the University of Alaska Anchorage. The results of these surveys were largely consistent with the results obtained by earlier soil sampling programs.

Drilling

Extensive drilling totaling 1,048,509.8 ft has been completed in 1,389 holes on the Pebble Project.  These drill programs took place during 19 of the 26 years between 1988 and 2013 and 2018 and 2019.  The most recent hole drilled on the project was completed on October 13, 2019. The spatial distribution and type of holes drilled is illustrated in Figure 5.

Figure 5 – Types of Drill Holes

Source: 2023 PEA

A detail of the drilling in the “deposit area” is shown in Figure 6.

Figure 6 – Drilling in Pebble Deposit Area

Source: 2023 PEA

Table 1 – Holes Drilled Pebble Project

Source: 2023 PEA

Notes:

Most of the footage on the Pebble Project was drilled using core drills. Only 18,716 ft was percussion-drilled from 229 rotary drill holes. Many of the cored holes were advanced through overburden, using a tricone bit with no core recovery. These overburden lengths are included in the core drilling total.

From early 2004 through 2013, all Pebble drill core was geotechnically logged on a drill run basis. Almost 70,000 measurements were made for a variety of geotechnical parameters on 737,000 ft of core drilling. Recovery is generally very good and averages 98.2% overall; two-thirds of all measured intervals have 100% core recovery. Detailed (domain-based) geotechnical logging and downhole surveys were also conducted between 2007 and 2012. Proper domain selection is the basis for rock mass classification and domain-based data is used extensively in open pit and underground mine design. In order to maximize the information from the 2007-2012 drill programs, several tools and techniques were added to a number of holes including: triple tube drilling, core orientation, acoustic televiewer probe and comprehensive point load testing complemented by laboratory UCS testing. Additionally, all Pebble drill core from the 2002 through 2013 and 2018 drill programs and the chip trays from the 2019 percussion program were photographed in a digital format.

A re-survey program of holes drilled at Pebble from 1988 to 2009 was conducted during the 2008 and 2009 field seasons. For consistency throughout the project, the resurvey program referenced the control network established by R&M Consultants in the U.S. State Plane Coordinate System Alaska Zone 5 NAVD88 Geoid99. The resurvey information was applied to the drill collar coordinates in the database in late 2009.

In 2009 and 2013, the survey locations, hole lengths, naming conventions and numbering designations of the Pebble drill holes were reviewed. This exercise confirmed that several shallow, non-cored, overburden drill holes described in some engineering and environmental reports were essentially the near-surface pre-collars of existing bedrock core drill holes. As these pre-collar and bedrock holes have redundant traces, the geologic information was combined into a single trace in the same manner as the wedged holes. In addition, a number of very shallow (less than 15 ft), small diameter, water-monitoring auger holes were removed from the exploration drill hole database, as they did not provide any geological or geochemical information.

Drill core from the 2002 to 2013 and 2018 programs was boxed at the rig and transported daily by helicopter to the secure logging facility in the village of Iliamna, as were the chip trays from the 2019 percussion drill program.

The locations of drill holes and representative sections through the Pebble deposit are shown on Figure 7. The two longitudinal sections included here4 (Figure 8 and Figure 9), illustrate drill hole traces, topographic and overburden surfaces along with colour-coded block model CuEq grades from the mineral resource estimate. CuEq calculations use metal prices: US$1.85/lb for Cu, US$902/oz for Au and US$12.50/lb for Mo, and recoveries: 85% Cu, 69.6% Au, and 77.8% Mo (Pebble West zone) and 89.3% Cu, 76.8% Au, 83.7% Mo (Pebble East zone).

Figure 7 – Drill Plan and Section Location

Source: 2023 PEA

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4 Additional sections are available in the 2023 PEA.

Figure 8 - Longitudinal Section 2156000N

Source: 2023 PEA

Figure 9 - Longitudinal Section 2157500N

Source: 2023 PEA

Sampling, Analysis and Security of Samples

The Pebble deposit has been explored by extensive core drilling, with 81,188 samples taken from drill core for assay analysis. Nearly all potentially mineralized Cretaceous core drilled and recovered has been sampled by halving in 10 ft lengths. Similarly, all core recovered from the Late Cretaceous to Early Tertiary cover sequence (referred to as Tertiary here and in Section 13 of the 2023 PEA has also been sampled, typically on 20 ft sample lengths, with some shorter sample intervals in areas of geologic interest. Unconsolidated overburden material, where it exists, is generally not recovered by core drilling and therefore not usually sampled.

Rock chips from the 229 rotary percussion holes were generally not sampled for assay analysis, as the holes were drilled for monitoring wells and environmental purposes. Only 35 samples were taken from the drill chips of 26 rotary percussion holes outside the Pebble deposit area, which were drilled for condemnation purposes.

Half cores remaining after sampling were replaced in the original core boxes and stored at Iliamna in a secure compound. Later geological, metallurgical, and environmental sampling took place on a small portion of this remaining core. Crushed reject samples from the 2006 through 2013 and the 2018 analytical programs are stored in locked containers at Delta Junction, AK. Drill core assay pulps from the 1989 through 2013 and the 2018 programs are stored at a secure warehouse in Surrey, BC.

Analytical work in 2002 and from 2004 to 2018 was completed by ALS Minerals Laboratories of North Vancouver, an ISO/IEC 17025:2005 certified laboratory.  Analytical work for the 2003 drilling program was completed by SGS Canada Inc. of Toronto, ON, an ISO 9002 registered, ISO 17025 accredited laboratory.

A total of 9,951 density measurements of Tertiary and Cretaceous rocks were taken using a water immersion method on whole and half drill core samples at the Iliamna core logging facility.  Rocks chosen for analysis were typical of the surrounding rock.  Core samples free of visible moisture were selected; they ranged from 3 to 12 in long, and averaged 11.8 in.

Further details on sample preparation and analytical procedures are available in the 2023 PEA.

Quality Assurance and Quality Control

Northern Dynasty maintained an effective QA/QC program consistent with industry best practices, which was continued from 2007 to 2013 under the Pebble Partnership. This program is in addition to the QA/QC procedures used internally by the analytical laboratories. The QA/QC program was independently reviewed by Analytical Laboratory Consultants Ltd (ALC, 2004 to 2007) and Nicholson Analytical Consulting (NAC, 2008 to 2012). The analytical consultants provided ongoing monitoring, including facility inspection and timely reporting of the performance of standards, blanks, and duplicates in the sampling and analytical program. The results of this program indicate that analytical results are of a high quality, suitable for use in detailed modeling and resource evaluation studies.

Table 2 describes the QA/QC sample types used in the program.

Table 2 - QA/QC Sample Types Used

Source: 2023 PEA

In July 2020, the original assay pulps from 938 sample intervals cored in years 1991, 2003, 2004 and 2005 Pebble deposit drilling were retrieved from a company warehouse for a study on the relationship between rhenium and molybdenum concentrations. The selected samples were originally analyzed for copper, molybdenum, and other elements, but had not been analyzed for rhenium. Samples were submitted to ALS Vancouver for multi-element analysis by four acid digestion ICP-MS finish (ALS method ME-MS61), along with 52 Pebble project-based standards, 17 nominal blanks and 48 duplicates. In addition to rhenium and molybdenum, the concentrations of copper, silver and 44 other elements were also determined in this study. As the control samples used had not originally been subject to round-robin analysis for rhenium, results of several hundred analyses at ALS Vancouver were used to establish reasonable concentration levels for them. These levels were corroborated with results obtained by other analytical laboratories using similar analytical methods.

As part of the 2020 rhenium study, additional elements including copper and molybdenum were analyzed by the multi-element method employed. The copper and molybdenum results obtained in 2020 were compared with the original assay results. A reasonable level of correspondence in concentrations of the matched pairs was obtained for each element.

Samples from the 2002 through 2012 core drilling of Northern Dynasty provide 91% of the assays used in the mineral resource estimate. These drilling and sampling programs were carried out in a proficient manner consistent with industry standard practices at the time the programs were completed. Core recovery was typically very good and averaged over 98%; two-thirds of all measured intervals have 100% core recovery. No significant factors of drilling, sampling, or recovery that impact the accuracy and reliability of the results were observed.

The remaining 9% of assays used in the mineral resource estimate derive from historical 1988 to 1992 and 1997 Teck core drill programs. Northern Dynasty expended considerable effort to assess the veracity of the Teck drilling over several years. This included re-surveying drill hole locations, reviewing remaining half core, extensive re-drilling of areas targeted by Teck, and plotting and comparison of Teck drill holes with nearby Northern Dynasty drill holes. No significant factors of the drilling, sampling or recovery of the Teck program that impact the accuracy and reliability of the results were observed.

2023 Data Verification

The QP completed several data verification checks in support of the Pebble Mineral Resource estimate. The verification process included a one-day site visit to the project to check geological procedures, drill core facility review, and a drill core storage inspection. Other data verification included selection of pulp samples for metal verification, a review of QA/QC performance for drilling completed between 2004-2018, and spot check comparisons of Au and Cu assays from the drill hole database against original assay records (lab certificates) with higher attention given to data reported from ALS laboratories from 2004 onward.

The QP also conducted a site visit.  The site visit included confirmation review of core logging against reported drill logs, inspection of assay sample tags against reported intervals in the data base, review of core handling procedures and an inspection of the core storage facility. The QP performed spot checks on geology and sample locations using previously selected drill holes stored in the core logging facility. Holes were selected previously by Northern Dynasty to be used as a review of various alteration, mineralization, and geology for the deposit. The spot checks were completed on six holes from the Pebble East Zone and two holes from Pebble West Zone. For all holes, drill logs were found to match the observed core and no issues were identified during spot checks against reported assay intervals.

The QP also selected 10 pulp sample intervals from 5 drill holes within the resource database. Samples were selected from a range of Cu grades within in the deposits, prioritized around years of high exploitation activity, (2004, 2007, 2008, 2011) and were spatially selected to get a distribution across the deposit in various lithology and alteration.

The selected pulps were pulled by Northern Dynasty employees from their Surrey warehouse. Once pulled they were sent by Northern Dynasty on behalf of the QP to ALS Geochemistry Laboratory in North Vancouver, BC. The QP chose the same analytical method as completed by Northern Dynasty to compare Au, Ag, Co and Mo results. Au was analyzed by fire assay using method ALS_PGM-ICP23, Ag, Cu, Mo using four acid ICP methods. Ag, Mo were analyzed using ALS_ME-ICP61 and Cu was analyzed using ALS_ME-ICP61a. All elements compare very well. The QP did not identify any material bias in the sample data, and the comparison results were found to be reasonable given the nature of the mineralization in the deposit. The QP independently reviewed the QA/QC data provided by Northern Dynasty for the reported resource. Northern Dynasty has employed an on-site QA/QC process including the insertion of standards, blanks and duplicate samples and regular intervals in the sample stream as documented in Section 11 of the 2023 PEA.

The QA/QC data consisted of assay values for Certified Reference Material (CRM). The assay results were analyzed for the 3 most used CRMs for years 2004 to 2012; CRM PLP-1, CRM CGS-16, and CRM CGS-3. In addition to CRM checks, assay results for blank and duplicate performance were reviewed for the entire dataset. The CRM review displayed no outstanding record of hard failures. Duplicate and blank performance were in line with expectation. Results were equivalent to what was reported by Northern Dynasty.

A total of 811 samples (1% of total database) were chosen for database verification, to be compared to original laboratory certificates. These samples were randomly selected from the Northern Dynasty database with higher attention given to assay data processed at ALS laboratories from 2004 – 2018. Twelve of the 811 samples selected were processed at SGS laboratories in 2003. No errors were found during the review.

QP also reviewed and calculated bulk density data against Northern Dynasty procedures. No issues were found with the process.

On completion of the data verification for Pebble, it is the opinion of the QP that the geological data collection, analytical methods, and QA/QC procedures used by Northern Dynasty are consistent with CIM Mineral Exploration Best Practice Guidelines.

Metallurgical Testwork

Metallurgical testwork for the project was initiated by Northern Dynasty in 2003 and continued under the direction of Northern Dynasty until 2008. From 2008 to 2013, metallurgical testwork progressed under the direction of the Pebble Partnership.

Geometallurgical studies were initiated by the Pebble Partnership in 2008 and continued through 2012. The principal objective of this work was to quantify significant differences in metal deportment that may result in variations in metal recoveries during mineral processing. The results of the geometallurgical studies indicate that the deposit comprises several geometallurgical (or material type) domains. These domains are defined by distinct, internally consistent copper and gold deportment characteristics that correspond spatially with changes in silicate and sulphide alteration mineralogy.

Metallurgical testwork and associated analytical procedures were performed by recognized testing facilities with extensive experience with these tests and analyses, with this type of deposit, and with the project. The samples selected for the comminution, copper-gold-molybdenum bulk flotation, and copper-molybdenum separation testing were considered to be representative of the various types and styles of mineralization at the Pebble deposit.

A conventional flotation process is proposed to produce saleable copper-gold and molybdenum concentrates. The flotation test results on variability samples derived from the 103 locked cycle flotation and the subsequent copper-molybdenum separation flotation tests indicate that marketable copper and molybdenum concentrates can be produced. The copper-gold concentrate will also contain gold and silver contents that meet or exceed payable levels in representative smelter contracts; the molybdenum concentrate will contain significant rhenium (Re), with a reported grade range from 791 to 832 g/t Re observed in the locked cycle test (LCT) results of the copper-molybdenum separation.

Gravity gold recovery tests were completed on three composite samples in 2010 and on four composite samples from the continuous testwork program. These demonstrated gold was recoverable by gravity and accordingly treatment of a side stream from the regrind circuit, with 1% overall gold recovery to a gravity concentrate. In the flowsheet for the proposed project, the gravity concentrate would be bagged and shipped off-site to a refinery. In the potential expansion scenarios with a secondary gold plant, the gravity concentrate would comprise a portion of the secondary gold plant feed.

A preliminary hydrometallurgical test program was performed on rougher and cleaner molybdenum concentrates to investigate the production of the marketable products of molybdenum trioxide (MoO3) and ammonium perrhenate (NH4ReO4). The test program included pressure oxidation leach, a series of metal extractions/purifications from the pregnant leach solution, and a calcination process. The tested methods were found technically feasible. Satisfactory dissolution rates of molybdenum and rhenium were obtained from the rougher molybdenum concentrate samples while additional alkaline leach is required on the pressure oxidation leach residues for the cleaner molybdenum concentrate samples.

The overall metal recovery projections of copper, gold, silver and molybdenum to concentrate in the 2023 PEA are identical to those reported in previous technical reports. Those values were adjusted to an increased primary grind size (from 125 µm to 135 µm) from those published in the 2018 technical report. A rhenium recovery estimate at a high level has been completed and included. Table 3 provides projected metals recoveries via flotation concentration. The recovery estimate bases are summarized as follows:

Table 3 - Projected Metallurgical Recoveries

Source: 2023 PEA

Note: Prepared by Tetra Tech, 2021. An additional 1% Au recovery to the gravity concentrate is expected. LOM average per financial model.

Mineral Resource Estimates

The current resource estimate is based on approximately 59,000 assays obtained from 699 drill holes. The resource was estimated by ordinary kriging and is presented in Table 4. The tabulation is based on copper equivalency (CuEq) that incorporates the contribution of copper, gold, and molybdenum. Although the estimate includes silver and rhenium, neither were used as part of the copper equivalency calculation in order to facilitate comparison with previous estimates which did not consider the minor economic contribution of either of these metals.

Table 4 - Pebble Deposit Mineral Resource Estimate at 0.3% Copper Equivalent Cut-off June 1, 2023

Source: 2023 PEA

Notes:

The 2023 PEA is preliminary in nature and 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. There is no certainty that the 2023 PEA results will be realized. Mineral resources that are not mineral reserves do not have demonstrated economic viability.

Proposed Mining Operations

Mining Method

The mining operations would use conventional open pit mining methods and equipment. The proposed Pebble mine would be a conventional drill, blast, truck, and shovel operation with an average mining rate of 70 M tons per year and an overall strip ratio of 0.12 tons of waste per ton of mineralized material.

The open pit would be developed in stages, with each stage expanding the area and deepening the previous stage. The final dimensions of the open pit would be 6,800 ft long and 5,600 ft wide, with depths to 1,950 ft.

The projected mining schedule was generated using five pushbacks and was based on a maximum processing capacity of 180,000 tons per day. Based on the selected ultimate pit, final pit design and the generated production schedule, the mining period of 21 years, including one year of pre-stripping followed by 20 years of production.

Recovery Method

The proposed processing plant is designed to process mineralized feed material at a rate of 180,000 tons per day. The designed process to treat feed material contemplates methods that are conventional and well-proven in the industry. The comminution and recovery processes proposed are used widely in commercial practice, with no significant elements of technological innovation.

The following unit operations would be employed to produce three final products: a copper-gold flotation concentrate, a molybdenum flotation concentrate and a gravity gold concentrate:

Figure 9 shows a simplified process flow diagram of the entire process route.

Figure 9 - Simplified Process Flowsheet

Source: 2023 PEA

The process plant flowsheet design was based on testwork results, previous study designs and industry standard practices. Further, the testwork results support the recovery projections used in the economic analysis.

The production summary for the proposed project is shown in Table 5. Production data includes all production whether payable in the spot market, under the Royalty Agreement, to third party metal stream partners or payable as a smelter deduction.

Table 5 – Proposed Project Production Summary

Source: 2023 PEA

Notes:

Project Infrastructure

The project is located in an area of Alaska that has minimal development and would require construction of both on-site and off-site infrastructure to support construction and operations of the proposed project.

The primary off-site infrastructure would incorporate a natural gas pipeline, marine terminal, ferry crossing of Iliamna Lake, and access roads from the marine terminal to Iliamna Lake, and from Iliamna Lake to the mine site. The marine terminal facility would include facilities capable of handling barges for concentrate transshipment as well as large ocean barges (400 x 100 ft) for transport of construction materials and operating supplies by container. The access road and ice-breaking ferry would provide year-round access between the marine terminal and the mine site for construction and operations. The natural gas for the power plants would be provided by local supply on the east side of Cook Inlet and would require a compressor station. The natural gas for power generation would be delivered by a pipeline extending across Cook Inlet to the marine terminal, then along the roadway corridor to the south shore of Iliamna Lake, across Iliamna Lake to Newhalen, cross-country to the Newhalen River bridge, and finally along the roadway corridor to the mine site.

The on-site facilities would provide all necessary support for construction and operation. These include temporary and permanent worker accommodations, power reticulation, site roads, administration buildings, truck shop, warehouse, maintenance facilities.

The proposed project site would also include tailings storage facilities, water management ponds, and water treatment plants (WTPs). Waste and water management at the project would be an integrated system designed to safely contain these materials, to facilitate water treatment and discharge, and to provide adequate process water to support the operations. The design of these facilities would incorporate data from a significant period of climate records, extensive site investigation, and several features intended to ensure safe operation.

The proposed project would incorporate a sophisticated water management plan with water collection, treatment, and discharge. That plan is based on the annual and seasonal variability of the incoming and receiving flows and achieving very specific water quality standards for the released water. Temporary water treatment facilities would be in place during construction, followed by three WTPs during the operations and closure phases.

Natural gas-fired power plants would be constructed at both the mine site and the marine terminal.

Environmental Considerations

The Pebble deposit is located on state land that has been specifically designated for mineral exploration and development. The Pebble area has been the subject of two comprehensive land-use planning exercises conducted by the Alaska Department of Natural Resources (ADNR): the first in the 1980s and the second in 2005 (subsequently revised in 2013). ADNR identified five land parcels (including Pebble) within the Bristol Bay planning area as having “significant mineral potential,” and where the planning intent is to accommodate mineral exploration and development. These parcels total 2.7% of the total planning area (ADNR, 2013).

Northern Dynasty began a field study program in 2004 to characterize the existing physical, chemical, biological, and social environments in the Bristol Bay and Cook Inlet areas where the project might occur. The Pebble Partnership compiled the data for the 2004-2008 study period into a multi-volume Environmental Baseline Document (EBD, PLP, 2012).

These studies were designed to:

Additional data collected from the 2009-2013 period was compiled into the Supplemental EBD (PLP, 2018) and transmitted to USACE. In 2017, select environmental baseline studies were re-initiated and expanded. Monitoring data collected through 2019 has been provided to USACE.

The baseline study program includes:

Closure and Reclamation Considerations

The Pebble Partnership’s core operating principles are governed by a commitment to conduct all mining operations, including reclamation and closure, in a manner that adheres to socially and environmentally responsible stewardship while maximizing benefits to state and local stakeholders.

Reclamation and closure of the proposed project falls under the jurisdiction of the ADNR Division of Mining, Land, and Water, and the ADEC. A miner may not engage in a mining operation until the ADNR has approved a reclamation plan for the operation. The Pebble Partnership submitted a preliminary closure plan to USACE in support of the EIS analysis. Four phases of closure are envisioned for the proposed project.

Permitting Considerations

The information in Summary of the 2023 PEA has been described in Three Year History above, and has been updated based on developments since completion of the 2023 PEA.

Capital Cost Estimates

The total initial capital cost for the design, construction, installation, and commissioning of the proposed project is estimated to be $6.77 B, which includes all direct, indirect, and Owner’s costs, as well as a contingency.

In order to reduce capital costs for Northern Dynasty, if approved, the proposed project would be developed with partners who will provide the primary infrastructure (marine terminal, access road, natural gas pipeline, mine site power plant) in return for lease payments or tolls at rates which would generate a return on investment to the providers of the infrastructure. The capital cost of infrastructure which may be provided by third parties is estimated at $2.64 B, which could reduce the initial capital required by Northern Dynasty for construction.

In addition, precious metal streaming is considered a project financing alternative and the 2023 PEA assumes $1.25 B could be available to the proposed project in the form of various streaming agreements.

The combination of third-party infrastructure financing and precious metal streaming would reduce the required capital investment from Northern Dynasty for the proposed project to $3.12 B; this scenario was evaluated in the economic model as the Base Case. A Full Capital Case, without the benefit of the precious metal stream financing and third-party infrastructure participation, was also evaluated as a sensitivity analysis.

Sustaining capital investment in the proposed project over the 20-year mine life is limited to TSF improvements, replacement of mobile equipment for mining, and road maintenance. These life-cycle costs are applied in the financial model on a year-by-year basis, with a cumulative total of $1.29 B including indirect and Owner’s costs as well a contingency. Sustaining capital investments in primary infrastructure developed with partners are factored into infrastructure lease payments.

Initial reclamation trust funding and letter of credit premiums during construction would total $208 M. The remaining mine closure and reclamation costs are not included in the capital or operating costs but are factored into the financial model to account for long-term closure and water treatment plant requirements. A reclamation fund of $1.62 B would be accumulated over the mine life comprising $966 M in contributions and $657 M in accrued interest.

Table 6 provides the initial and sustaining capital cost estimates for the full capital case.