Stuhini Exploration — Capital/Financing Update 2025

Sep 16, 2025

FORM 51-102F3
MATERIAL CHANGE REPORT

Item 1: Name and Address of Company
Bunker Hill Mining Corp. (“Bunker Hill” or the “Company”)
300 – 1055 West Hastings Street
Vancouver, BC V6E 2E9

Item 2: Date of Material Changes
September 5, 2025 and September 15, 2025

Item 3: News Releases
The news releases announcing the material changes referred to in this report were disseminated on September 5, 2025 and September 15, 2025 through Globe Newswire, copies of which have been filed under Bunker Hill’s profile on SEDAR+.

Item 4: Summary of Material Changes
On September 5, 2025, Bunker Hill announced it had entered into an agreement with Haywood Securities Inc. (“Haywood”), as lead underwriter and sole bookrunner, on its own behalf and on behalf of a syndicate of underwriters including BMO Capital Markets (together with Haywood, the “Underwriters”) pursuant to which the Underwriters have agreed to purchase, on a “bought deal” private placement basis, 375,000,000 units of the Company (the “Units”) at a price per Unit of C$0.12 for aggregate gross proceeds to the Company of C$45,000,000.

On September 15, 2025, Bunker Hill announced that it revised the terms of the “bought deal” private placement offering to provide for Canadian dollar and United States dollar denominated tranches consisting of: (i) 150,000,000 Units issued at a price per Unit of C$0.12 (the “CAD Offering Price”) for gross proceeds of C$18,000,000, and (ii) 225,000,000 Units issued a price per Unit of US$0.08711 (the “USD Offering Price”) for gross proceeds of US$19,599,750.

Each Unit will consist of one share of common stock of the Company (a “Common Share”) and one common stock purchase warrant of the Company (a “Warrant”). Each Warrant will entitle the holder thereof to acquire one share of common stock of the Company (a “Warrant Share”) at a price of C$0.17 per Warrant Share for a period of 60 months from the Closing Date (as defined below).

Item 5:

5.1 Full Description of Material Change
On September 5, 2025, Bunker Hill announced it had entered into an agreement with Haywood, as lead underwriter and sole bookrunner, on its own behalf and on behalf of the Underwriters, pursuant to which the Underwriters have agreed to purchase, on a “bought deal” private placement basis, 375,000,000 Units of the Company at a price per Unit of C$0.12 for aggregate gross proceeds to the Company of C$45,000,000.

On September 15, 2025, Bunker Hill announced that it revised the terms of the “bought deal” private offering to provide for Canadian dollar and United States dollar denominated tranches consisting of: (i) 150,000,000 Units issued at the CAD Offering Price for gross proceeds of C$18,000,000 (the “CAD Offering”), and (ii) 225,000,000 Units issued at the USD Offering Price for gross proceeds of US$19,599,750 (the “USD Offering” and, together with the CAD Offering, the “Offering”).

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Each Unit will consist of one Common Share and one Warrant. Each Warrant will entitle the holder thereof to acquire one Warrant Share at a price of C$0.17 per Warrant Share for a period of 60 months following the Closing Date.

In connection with the Offering, the Company has agreed to grant the Underwriters an option to purchase up to an additional 56,250,000 Units at the CAD Offering Price, exercisable in whole or in part at any time up to 48 hours prior to the Closing Date.

A cornerstone investor is expected to subscribe for the entirety of the USD Offering (the "Cornerstone Subscription"). Completion of the Offering is subject to the completion of the Cornerstone Subscription.

The Company intends to use the net proceeds of the Offering to advance the construction of the Bunker Hill Mine and move it to commercial production, and for general corporate and working capital purposes.

The Offering is being made to eligible substituted purchasers resident in each of the Provinces of Canada and Territories of Canada in accordance with National Instrument 45-106 – Prospectus Exemptions and/or in jurisdictions other than Canada that are mutually agreed to by the Company and the Underwriters, subject to compliance with applicable regulatory requirements.

The Offering is expected to close on September 29, 2025 (the "Closing Date"), and is subject to certain closing conditions including, but not limited to, the receipt of all necessary approvals including the conditional listing approval of the TSX Venture Exchange and the applicable securities regulatory authorities.

In consideration for their services, the Company has agreed to pay the Underwriters a cash commission equal to 6.0% of the gross proceeds from the Offering, provided that the cash commission will be equal to 3.0% of the aggregate gross proceeds raised in the Offering from certain purchasers listed on the president's list (the "President's List"), and issue that number of non-transferable compensation options (the "Compensation Options") as is equal to 6.0% of the aggregate number of Units sold under the Offering, provided that the number of Compensation Options will be equal to 3.0% of the aggregate number of Units issued by the Company to certain purchasers on the President's List. In consideration of their services, the Company may pay certain finders (each, a "Finder"), including ZED Financial Partners, a cash commission equal to 4.0% of the aggregate gross proceeds raised from certain subscribers introduced by such Finders to the Company in the Offering, and issue that number of Compensation Options as is equal to 4.0% of the aggregate number of Units sold under the Offering to subscribers introduced by the Finders.

Each Compensation Option is exercisable to acquire one share of common stock of the Company at a price equal C$0.12 per share for a period of 24 months from the Closing Date.

The Units have not been and will not be registered under the U.S. Securities Act of 1933, as amended, and may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirements. This material change report shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of the securities in any State in which such offer, solicitation or sale would be unlawful.

The securities to be issued under the Offering will be subject to statutory hold period of four months and one day in accordance with applicable Canadian securities laws and to a minimum concurrent six-month hold period in accordance with applicable U.S. securities laws. Such securities have not been registered under the U.S. Securities Act or any U.S. state securities laws, and may not be offered or sold in the United States without registration under the U.S. Securities Act and all applicable state securities laws or compliance with requirements of an applicable exemption therefrom. This material change report shall not constitute an offer to sell or the solicitation of an

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offer to buy these securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or other jurisdiction.

5.2 Disclosure for Restructuring Transaction

Not applicable.

Item 6: Reliance on Subsection 7.1(2) or (3) of National Instrument 51-102

Not applicable.

Item 7: Omitted Information

Not applicable.

Item 8: Executive Officer

Brenda Dayton
Vice President, Investor Relations
T: 604.417.7952
E: brenda.dayton@bunkerhillmining.com

Item 9: Date of Report

September 15, 2025