Northern Dynasty: Third Tranche of Amended Royalty Agreement Completed with Receipt of US$12 Million

Northern Dynasty: Third Tranche of Amended Royalty Agreement Completed

with Receipt of US$12 Million

June 2, 2025 Vancouver – Northern Dynasty Minerals Ltd. (TSX: NDM; NYSE American: NAK) ("Northern

Dynasty" or the "Company") reports it has received payment of $12 million representing the third tranche

investment under the Company’s royalty agreement dated July 26, 2022 , as amended (the ”Royalty

Agreement”). Concurrent with the completion of the investment, the Company and the royalty investor (the

“Royalty Holder”) agreed to further amend the terms of the Royalty Agreement (the “Second Amendment”)

to increase flexibility of payment installments and to extend the July 26, 2025 expiration date. All currency

figures are U.S. dollars.

Under the initial amendment to the Royalty Agreement, as reported in the Company’s news release dated

November 13, 2023, the Royalty Holder received, among other things, the right to fund the three remaining

$12 million tranches on or before July 26, 2025. Completion of each additional tranche entitles the Royalty

Holder the right to receive an additional 2% of the payable gold production and 6% of the payable silver

production from the Pebble Project.

In exchange for an early payment of the third $12 million tranche before the July 26, 2025 deadline, the

Company has agreed to extend the deadline for completion of the remaining two tranches to September 30,

2025. Additionally, if the fourth $12 million tranche is completed on or before September 30, 2025, the

Royalty Holder will have the right to complete the fifth and final $12 million tranche investment at any time

up to and including December 31, 2025. The aggregate total purchase price of $60 million and maximum

royalty rates (10% of payable gold production and 30% of payable silver production) remain unchanged from

the original Royalty Agreement.

“We are pleased to see the Royalty Holder make its third payment of $12 million, bringing its total investment

in the royalty up to $36 million of a possible $60 million available under the Royalty Agreement,” said Ron

Thiessen, Northern Dynasty President and CEO.

About Northern Dynasty Minerals Ltd.

Northern Dynasty is a mineral exploration and development company based in Vancouver, Canada. Northern

Dynasty's principal asset, owned through its wholly owned Alaska-based U.S. subsidiary, Pebble Limited

Partnership, is a 100% interest in a contiguous block of 1,840 mineral claims in Southwest Alaska, including

the Pebble deposit, located 200 miles from Anchorage and 125 miles from Bristol Bay. The Pebble Partnership

is the proponent of the Pebble Project.

For further details on Northern Dynasty and the Pebble Project, please visit the Company's website at

www.northerndynastyminerals.com or contact Investor services at (604) 684-6365 or within North America

at 1-800-667-2114. Public filings, which include forward looking information cautionary language and risk

factor disclosure regarding the Company and the Pebble Project can be found in Canada at www.sedarplus.ca

and in the United States at www.sec.gov.

Ronald W. Thiessen

President & CEO

U.S. Media Contact:

Dan Gagnier, Gagnier Communications (646) 569-5897

2

Forward Looking Information and other Cautionary Factors

This document includes certain statements that may be deemed "forward-looking statements" under the United States Private

Securities Litigation Reform Act of 1995 and under applicable provisions of Canadian provincial securities laws. All statements in this

document, other than statements of historical facts, which address permitting and the development and production for the Pebble

Project and the ability of the Company to successfully complete the full financing transaction discussed above (the “Royalty

Financing”) are forward-looking statements. Additional forward looking statements made by the Company under its continuous

disclosure obligations include statements regarding (i) the development plan for the Pebble Project (ii) the right-sizing and de-risking

of the Pebble Project, (iii) the design and operating parameters for the Pebble Project development plan, including projected capital

and operating costs, (iv) the social integration of the Pebble Project into the Bristol Bay region and benefits for Alaska, (v) the political

and public support for the permitting process, (vi) the ability of the Pebble Project to ultimately secure all required federal and state

permits, (vii) the ability of the Company and/or the State of Alaska to challenge the Environmental Protection Agency’s (“EPA’s”) Final

Determination process under the Clean Water Act and ultimately the U.S. Army Corps of Engineers Record of Decision (“USACE ROD”)

through legal actions; (viii) exploration potential of the Pebble Project, (ix) future demand for copper, gold and other metals, (x) if

permitting is ultimately secured, the ability to demonstrate the Pebble Project is ultimately commercially viable, and (xi) the potential

addition of partners in the Pebble Project. Although NDM 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 or regarding the ability of NDM to develop the Pebble Project in light of the USACE ROD

and its subsequent remand decision and the EPA’s Final Determination, establish the commercial feasibility of the Pebble Project,

achieve the required financing or develop the Pebble Project.

Forward-looking statements are necessarily based upon a number of factors and assumptions that, while considered reasonable by

NDM as of the date of such statements, are inherently subject to significant business, economic and competitive uncertainties and

contingencies. Assumptions used by NDM to develop forward-looking statements 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) NDM’s estimates of mineral resources will not change,

and NDM will be successful in converting mineral resources to mineral reserves, (iv) NDM will be able to establish the commercial

feasibility of the Pebble Project, and (v) NDM will be successful in its legal action against the EPA and the USACE and any action taken

by the EPA in connection with the Final Determination will ultimately not be successful in restricting or prohibiting development of

the Pebble Project.

There is no assurance that the Royalty Holder will complete the two remaining investment tranches under the Royalty Agreement,

In addition, 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) the current development plan may not reflect the ultimate mine

plan for the Pebble Project, (ii) 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, (iii) finalization of the mine plan for the

Pebble Project, (iv) the completion of feasibility studies demonstrating that any Pebble Project mineral resources that can be

economically mined, (v) completion of all necessary engineering for mining and processing facilities, (vi) the ability of NDM to secure

a partner for the development of the Pebble Project, and (vi) receipt by NDM of significant additional financing, including the full

Royalty Financing, to fund these objectives as well as funding mine construction. NDM is also subject to the specific risks inherent in

the mining business as well as general economic and business conditions. Investors should also consider the risk factors identified in

the Company’s Annual Information Form for the year ended December 31, 2024, as filed on SEDAR+ (www.sedarplus.ca) and included

in its annual report on Form 40-F filed on EDGAR (www.sec.gov), as well as the risk factors set out in the Company’s subsequent

public continuous disclosure filings available on SEDAR+ and EDGAR. For more information on the Company, Investors should review

the Company's filings with the United States Securities and Exchange Commission at www.sec.gov and its home jurisdiction filings

that are available at www.sedarplus.ca.

The National Environment Policy Act Environmental Impact Statement process requires a comprehensive “alternatives assessment”

be undertaken to consider a broad range of development alternatives, the final project design and operating parameters for the

Pebble Project and associated infrastructure may vary significantly from that currently contemplated. As a result, the Company will

continue to consider various development options and no final project design has been selected at this time.