Execution Version

AGREEMENT OF PURCHASE AND SALE

ADAR MINING CORP.

and

PREMIER SILVER CORP. and 1267104 B.C. LTD.

March 10, 2025

THIS AGREEMENT is made as of March 10, 2025.

BETWEEN:

ADAR MINING CORP. (hereinafter referred to as "Adar")

AND:

PREMIER SILVER CORP. and 1267104 B.C. LTD. (hereinafter together referred to as the "Sellers")

WHEREAS on February 6, 2025, the Sellers each filed a notice of intention to make a proposal pursuant to section 50.4 of the Bankruptcy and Insolvency Act (Canada), and Alvarez & Marsal Canada Inc. was appointed as proposal trustee (in such capacity, the "NOI Trustee") in respect of such notice and the related proceedings (the "NOI Proceedings");

AND WHEREAS as soon as reasonably practicable (and subject to availability of the Court (as defined herein) following execution of this Agreement, the Sellers intend to apply for the Approval and Vesting Order (as defined herein);

AND WHEREAS, the Sellers desire to sell, transfer, convey, deliver and assign to the Purchaser (as defined herein) and the Purchaser desires to purchase and assume from the Sellers the Purchased Assets (as defined herein) in accordance with the terms of this Agreement;

NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the Sellers and the Purchaser agree as follows:

ARTICLE 1 INTERPRETATION

1.1 Defined Terms

For the purposes of this Agreement, unless the context otherwise requires, the following terms shall have the respective meanings set out below and grammatical variations of such terms shall have corresponding meanings:

"126" means 1267104 B.C. Ltd.;

"Adar Debt" means all indebtedness owing by Premier Silver and 126 to Adar together with interest, fees and costs accruing hereafter, as well as:

(a) any additional amounts advanced hereafter, including all amounts owing by either Seller pursuant to the Loan Agreement; and
(b) all of the secured and unsecured claims of Adar against the Sellers, including all claims advanced in the Receivership Proceedings;

"Approval and Vesting Order" means an order granted by the Court substantially in the form attached as Schedule A, which, subject to Court approval, will, among other things:

(a) authorize and approve this Agreement and the execution and delivery hereof by the Sellers;
(b) authorize and direct the Sellers to complete the Transaction; and
(c) provide for the vesting of all of the Sellers' right, title and interest in and to the Purchased Assets in the Purchaser in accordance with the terms and conditions of this Agreement, free and clear of all claims against the Purchased Assets of every nature or kind whatsoever and howsoever arising, including all Encumbrances, upon the delivery of a certificate by the NOI Trustee certifying, among other things, that the Transaction have been completed to its satisfaction;

"Business Day" means any day, other than a Saturday or a Sunday, on which commercial banks in Vancouver, British Columbia, or Toronto, Ontario are open for business during normal banking hours;

[Competitive information redacted for commercial reasons];

"Closing" means the closing of the Transaction, including the satisfaction of the Purchase Price and the delivery of the Closing Deliveries on the Closing Date;

"Closing Date" means the day selected by the Purchaser as indicated by way of notice from the Purchaser to the Sellers, provided such day is no earlier than 5 days after, and no later than 30 days after, each of the conditions precedent set forth in Sections 3.1, 3.2 and 3.3 is duly satisfied or waived, and provided further that if such day is not a Business Day, then the Closing Date shall be the next following Business Day, or such other or later date as the parties may agree in writing;

"Closing Deliveries" means the agreements, instruments and other documents to be delivered by the Sellers to the Purchaser pursuant to Section 2.7 and the agreements, instruments, money and other documents to be delivered by the Purchaser to the Sellers pursuant to Section 2.8;

"Court" means the Supreme Court of British Columbia;

"Encumbrance" means any and all encumbrances, liens, charges, hypothecs, pledges, mortgages, title retention agreements, security interests of any nature, adverse claims, exceptions, reservations, easements, encroachments, servitudes, restrictions on use, rights of occupation, any matters capable of registration against title, options, rights of first offer or refusal or similar rights, restrictions on voting (in the case of any voting or equity interest), rights of pre-emption or privilege or any contract to create any of the foregoing;

"Evidence of Release" has the meaning set out in Section 2.3;

"Excellon" means Excellon Resources Inc., a corporation formed under the laws of the Province of Ontario;

"Excellon Consideration Shares" has the meaning set out in Section 2.3;

"Excellon Shares" means common shares in the capital of Excellon, as the same may be subdivided, consolidated, constituted or reconstituted from and after the date hereof;

"Final Order" means the Approval and Vesting Order after (i) the expiry of the applicable appeal period; or (ii) in the event of an appeal or application for leave to appeal or to stay, vary, supersede, set aside or vacate the Approval and Vesting Order, final determination of such appeal or application by the applicable court or appellate tribunal;

"Governmental Authority" means any domestic or foreign government, including any federal, provincial, state, territorial or municipal government and any government department, body, ministry, agency, tribunal, commission, board, court, bureau or other authority exercising or purporting to exercise executive, legislative, judicial, regulatory or administrative functions of, or pertaining to, government;

"GST/HST" means all taxes payable under the Excise Tax Act (Canada), including goods and services taxes and any harmonized sales taxes in applicable provinces, or under any provincial legislation similar to the Excise Tax Act (Canada), and any reference to a specific provision of the Excise Tax Act (Canada) or any such provincial legislation shall refer to any successor provision thereto of like or similar effect;

"Loan Agreement" means the loan agreement [competitive information redacted for commercial reasons];

"Minera" means Minera CRC S.A.C., a corporation formed under the laws of Peru;

"NOI Proceedings" has the meaning set out in the Recitals hereto;

"NOI Trustee" has the meaning set out in the Recitals hereto;

"NOI Trustee Costs" means all proper fees and expenses of the NOI Trustee (including the fees and expenses of its counsel) in respect of the NOI Proceedings;

"Outside Date" means September 15, 2025;

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"Premier Silver" means Premier Silver Corp., a corporation formed under the laws of Province of British Columbia;

"PST" means all provincial sales tax imposed pursuant to the Provincial Sales Tax Act (British Columbia) or any equivalent or corresponding provincial or territorial legislation imposing a similar tax that may apply in respect of the Transaction;

"Purchase Price" has the meaning set out in Section 2.2;

"Purchased Assets" means all of the right, title and interest of:

(a) Premier Silver in and to all of its common shares of a nominal value of PEN 1.00 each in the capital of Minera, being 99.99% of the issued and outstanding shares in the capital of Minera; and

(b) 126 in and to all of its common share of a nominal value of PEN 1.00 in the capital of Minera, being 0.01% of the issued and outstanding shares in the capital of Minera;

"Purchaser" means Adar or, following assignment by Adar in accordance with Section 6.3, Excellon as the assignee of Adar;

"Receivership Proceedings" means the receivership proceedings commenced by Adar in the Court, Vancouver Registry Action No. S224453.

"Stream Revenue Sharing Agreement" has the meaning set out in Section 2.2(c);

"Stream Share" means those amounts (if any) payable pursuant to and in accordance with the Stream Revenue Sharing Agreement;

[Competitive information redacted for commercial reasons];

"Transaction" means the transaction of purchase and sale of the Purchased Assets contemplated by this Agreement; and

"Treaty Exemption" has the meaning set out in Section 2.5(b).

1.2 Currency

Unless otherwise indicated, all dollar amounts in this Agreement are expressed in Canadian currency.

1.3 Sections and Headings

The division of this Agreement into Articles and Sections and the insertion of headings are for convenience of reference only and shall not affect the interpretation of this Agreement. Unless otherwise indicated, any reference in this Agreement to an Article, Section or Schedule refers to the specified Article, Section or Schedule of or to this Agreement.

1.4 Number, Gender and Persons

In this Agreement, words importing the singular number only shall include the plural and vice versa, words importing gender shall include all genders and words importing persons shall include individuals, corporations, partnerships, associations, trusts, unincorporated organizations, governmental bodies and other legal or business entities of any kind whatsoever.

1.5 Interpretation of Certain Non-Capitalized Terms

The word “including” means including without limitation.

1.6 Entire Agreement

This Agreement constitutes the entire agreement between the parties with respect to the subject matter hereof and supersedes all prior agreements, understandings, negotiations and discussions, whether written or oral. There are no conditions, covenants, agreements, representations, warranties or other provisions, express or implied, collateral, statutory or otherwise, relating to the subject matter hereof except as herein provided.

1.7 Time of Essence

Time shall be of the essence of this Agreement.

1.8 Severability

If any provision of this Agreement is determined by a court of competent jurisdiction to be invalid, illegal or unenforceable in any respect, such determination shall not impair or affect the validity, legality or enforceability of the remaining provisions hereof, and each provision is hereby declared to be separate, severable and distinct.

1.9 Applicable Law

This Agreement shall be construed, interpreted and enforced in accordance with, and the respective rights and obligations of the parties shall be governed by, the laws of the Province of British Columbia and the federal laws of Canada applicable therein, and each party irrevocably and unconditionally submits to the non-exclusive jurisdiction of the courts of such province and all courts competent to hear appeals therefrom.

1.10 Contra Proferentum

It is acknowledged that this Agreement has been drafted through the equal participation of counsel for the parties, respectively, and that the contra proferentum rule is therefore inapplicable if any dispute were to arise as to the precise meaning of any of the terms of this Agreement.

ARTICLE 2

PURCHASE AND SALE

2.1 Purchase and Sale

The Sellers hereby agree to sell, transfer, convey, deliver and assign the Purchased Assets to the Purchaser and the Purchaser hereby agrees to purchase the Purchased Assets from the Sellers in consideration of the payment of the Purchase Price on the Closing Date, on the terms and subject to the conditions set out in this Agreement. The Purchaser shall not assume any of the liabilities, debts or obligations of the Sellers.

2.2 Purchase Price.

The purchase price payable by the Purchaser to the Sellers for the Purchased Assets shall be the sum of the following (the "Purchase Price"):

(a) [competitive information redacted for commercial reasons];

(b) the amount of the Adar Debt as of the Closing Date;

(c) [competitive information redacted for commercial reasons], being the fair market value of the Stream Share granted in favour of Premier Silver, substantially in the form attached as Schedule B (the "Stream Revenue Sharing Agreement"); and

(d) [competitive information redacted for commercial reasons].

2.3 Satisfaction of Purchase Price

The Purchase Price shall be satisfied on Closing by:

(a) as to the amount referred to in Section 2.2(a), a cash payment of USD $10 to 126 by wire transfer, bank transfer or direct deposit of immediately available funds to such bank account as may be designated by 126;

(b) as to the amount referred to in Section 2.2(b), by cancellation and release of all of the Adar Debt as of the Closing Date as evidenced by a release in a form to be mutually agreed upon by the parties, acting reasonably (the "Evidence of Release");

(c) as to the amount referred to in Section 2.2(c), by Adar entering into the Stream Revenue Sharing Agreement with Premier Silver, and granting the Stream Share therein; and

(d) as to the amount referred to in Section 2.2(d), by the issuance to Premier Silver of such number of the Excellon Shares that is equal to CAD $400,000 divided by the volume weighted average price of the Excellon Shares on the Toronto Stock Exchange for the five trading days ending on the trading day prior to the Closing

Date (or such other price as may be required by applicable securities and exchange regulatory authorities) (the "Excellon Consideration Shares").

2.4 Allocation of Purchase Price

The Purchase Price shall be allocated among the Purchased Assets as to:

(a) USD $10.00 to the Purchased Assets being sold by 126 hereunder, and
(b) the balance of the Purchase Price to the Purchased Assets being sold by Premier Silver hereunder.

2.5 [Competitive information redacted for commercial reasons].

2.6 Transfer

On Closing, on and subject to the terms and conditions of this Agreement and the Approval and Vesting Order, the Sellers shall sell, transfer and assign to the Purchaser, and the Purchaser shall purchase from the Sellers, all of the Purchased Assets, which shall be free and clear of all Encumbrances, to the extent and as provided for in the Approval and Vesting Order.

2.7 Closing Deliveries by Sellers

On or before the Closing Date, subject to the provisions of this Agreement, each of the Sellers shall execute (as applicable) or cause to be executed and deliver to the Purchaser, each of which shall be in form and substance satisfactory to the Purchaser acting reasonably:

(a) a receipt for the satisfaction of the Purchase Price;
(b) a copy of the issued and entered Approval and Vesting Order;
(c) a copy of the resolutions of the shareholders of Minera approving: (i) the transfer of the Purchased Assets to the Purchaser; and, (ii) removing and appointing such persons as officers and legal representatives of Minera as the Purchaser may nominate;
(d) the Stock Ledger Book with the share transfer entry signed by a competent and authorized officer of Minera, to record the transfer of the Purchased Assets;
(e) the Certificate of Canadian Residence of each of the Sellers;
(f) the Stream Revenue Sharing Agreement, duly executed by Premier Silver;
(g) a release substantially in the form attached hereto as Schedule C from the Sellers and their shareholders, directors, officers, agents and similar parties in favour of Adar, Excellon and all of their respective affiliates and related parties, shareholders, directors, officers, agents and similar parties, [competitive information redacted for commercial reasons];

(h) a certificate of the Sellers certifying that all of the representations and warranties of the Sellers contained in this Agreement are true and correct as if made as of the Closing Date;

(i) a certificate of an officer of each Seller confirming that all conditions to Closing in its favour are either satisfied or waived; and

(j) any other documents required pursuant to this Agreement in form and substance satisfactory to the Purchaser and the Sellers, each acting reasonably.

2.8 Closing Deliveries by the Purchaser

On or before the Closing Date, subject to the provisions of this Agreement, the Purchaser shall deliver to the Sellers, each of which shall be in form and substance satisfactory to the Sellers acting reasonably:

(a) the payment referred to in Section 2.3(a);

(b) the Evidence of Release executed by the Purchaser;

(d) the Excellon Consideration Shares issued in the name of Premier Silver;

(e) a release in the form attached as Schedule D hereto from Minera, in favour of the Sellers and all of their affiliates and related parties, shareholders, directors, officers, agents and similar parties;

(f) a certificate of the Purchaser certifying that all of the representations and warranties of the Purchaser contained in this Agreement are true and correct as if made as of the Closing Date;

(g) a certificate of an officer of the Purchaser confirming that all conditions to Closing in its favour are either satisfied or waived; and

(h) any other documents required pursuant to this Agreement in form and substance satisfactory to the Purchaser and the Sellers, each acting reasonably.

2.9 Additional Covenants

The Sellers shall, as soon as reasonably practicable (and subject to availability of the Court) following execution of this Agreement, apply to the Court for the Approval and Vesting Order. For greater certainty, the form of Approval and Vesting Order being submitted to the Court must be on terms acceptable to the Purchaser, acting reasonably.

2.10 Post-Closing Covenants

(a) Adar will, as soon as reasonably practicable following Closing, file the Transaction Closing Certificate, as defined in the Consent Order dated January 30, 2025 filed in the Receivership Proceedings, and then a notice of discontinuance in respect of the Receivership Proceedings.

(b) On the later to occur of (i) Closing and (ii) the transfer of all outstanding and issued shares in the authorized share structure of Premier held by each of (x) [personal information redacted for confidentiality reasons], (y) [personal information redacted for confidentiality reasons] and (z) [personal information redacted for confidentiality reasons], to Premier:

(i) as soon as reasonably practicable, Premier will take commercially reasonable efforts to remove all references to [personal information redacted for confidentiality reasons] from the Premier website and all of Premier's public-facing documents; and

(ii) the Sellers will provide a release, in substantially the form attached hereto as Schedule C, in favour of, [personal information redacted for confidentiality reasons].

2.11 Further Assurances

Each party to this Agreement covenants and agrees that it will at all times both before and after the Closing Date, at the expense of the requesting party, promptly execute and deliver all such documents, including, without limitation, all such additional conveyances, transfers, consents and other assurances and do all such other acts and things as the other party, acting reasonably, may from time to time request be executed or done in order to better evidence or perfect or effectuate any provision of this Agreement or of any agreement or other document executed pursuant to this Agreement or any of the respective obligations intended to be created hereby or thereby.

ARTICLE 3

CONDITIONS

3.1 Conditions of Closing in Favour of the Purchaser

The sale and purchase of the Purchased Assets is subject to the following terms and conditions for the exclusive benefit of the Purchaser, to be performed or fulfilled at or prior to Closing (or such earlier date as may be specified below):

(a) Representations and Warranties. On Closing, the representations and warranties of each of the Sellers contained in this Agreement shall be true and correct as if made as of the Closing Date;

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(b) Covenants. All of the terms, covenants and conditions of this Agreement to be complied with or performed by the Sellers on or before the Closing shall have been complied with or performed in all material respects;

(d) Capitalization. The Sellers shall have capitalized all of the indebtedness owing by Minera to each of them such that no such debt shall remain outstanding, and the Purchaser shall have received evidence in connection therewith, including the form of proxy attached as Schedule E hereto and such other documents in such form and substance as it may require, acting reasonably; and

(e) Approval and Vesting Order. The Approval and Vesting Order shall have been issued and entered.

3.2 Conditions of Closing in Favour of the Sellers

The sale and purchase of the Purchased Assets is subject to the following terms and conditions for the exclusive benefit of the Sellers, to be performed or fulfilled at or prior to Closing (or such earlier date as may be specified below):

(a) Representations and Warranties. On Closing, the representations and warranties of the Purchaser contained in this Agreement shall be true and correct as if made as of the Closing Date;

(b) Covenants. All of the terms, covenants and conditions of this Agreement to be complied with or performed by the Purchaser on or before the Closing shall have been complied with or performed in all material respects;

(d) Return of Premier Shares. All outstanding and issued shares in the authorized share structure of Premier held by each of (i) [personal information redacted for confidentiality reasons], (ii) [personal information redacted for confidentiality reasons] and (iii) [personal information redacted for confidentiality reasons], have been transferred to Premier for cancellation.

3.3 Conditions of Closing for the Mutual Benefit of the Sellers and Purchaser

The sale and purchase of the Purchased Assets is subject to the following terms and conditions for the mutual benefit of the Sellers and the Purchaser, to be performed or fulfilled at or prior to Closing (or such earlier date as may be specified below):

(a) Approval and Vesting Order. The Approval and Vesting Order shall have been granted by the Court and such Approval and Vesting Order will be a Final Order;

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(b) No Action or Proceeding. No legal or regulatory action or proceeding shall be pending or threatened by any Governmental Authority to enjoin, restrict or prohibit the purchase and sale of the Purchased Assets contemplated hereby; and

(c) Injunctions. There shall be in effect no injunction against closing the Transaction entered by a court of competent jurisdiction.

ARTICLE 4

REPRESENTATIONS AND WARRANTIES

4.1 Representations and Warranties of the Sellers

Each of the Sellers represents and warrants to and in favour of the Purchaser that:

(a) each Seller has been duly incorporated and organized and validly subsisting under the laws of the Province of British Columbia;

(b) subject to the granting of the Approval and Vesting Order, each of the Sellers has the requisite corporate power and authority to enter into this Agreement and to perform its obligations hereunder and to consummate the Transaction;

(c) this Agreement has been duly executed and delivered by each of the Sellers and is a legal, valid and binding obligation of each Seller, enforceable against each Seller in accordance with its terms;

(d) each Seller is not a non-resident of Canada for purposes of the Income Tax Act (Canada); and

(e) subject only to the entry of the Approval and Vesting Order, each of the Sellers will on Closing have the necessary authority to carry out the Transaction on the terms and subject to the conditions set out in this Agreement.

4.2 Representations and Warranties of the Purchaser

The Purchaser represents and warrants to and in favour of the Sellers that, as of the date of this Agreement:

(a) Adar is a corporation duly incorporated and organized and validly subsisting under the laws of its jurisdiction of incorporation and has the corporate power to enter into this Agreement and to perform its obligations hereunder and to consummate the Transaction;

(b) this Agreement has been duly authorized, executed and delivered by the Purchaser and is a legal, valid and binding obligation of the Purchaser, enforceable against the Purchaser by the Seller in accordance with its terms;

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(c) Adar is the valid and only owner of the Adar Debt and has the authority to compromise and extinguish all secured and unsecured claims against Premier Silver and 126 that Adar has alleged are owing to it by the Sellers, including all claims advanced in the Receivership Proceedings;

(d) Excellon is a corporation duly incorporated and organized and validly subsisting under the laws of the Province of Ontario and has the corporate power to acquire this Agreement and, subject to the assignment contemplated by Section 6.3 of this Agreement, to perform its obligations hereunder and to consummate the Transaction;

(e) Excellon is a “Canadian”, as defined in the Investment Canada Act (Canada);

(f) Excellon is not a non-resident of Canada for purposes of the Income Tax Act (Canada); and

(g) Excellon is a registrant for purposes of Part IX of the Excise Tax Act (Canada) whose registration number is [competitive information redacted for commercial reasons].

4.3 Survival

The representations, warranties and certifications of the Sellers and the Purchaser contained in this Agreement and in any Closing Deliveries shall survive the Closing.

ARTICLE 5 TERMINATION

5.1 Termination

(a) At any time prior to Closing, this Agreement will terminate automatically, and without any action or notice by any party, immediately upon:

(i) the issuance of a final and non-appealable order, decree, or ruling or any other action by a Governmental Authority to restrain, enjoin or otherwise prohibit the Transaction; or

(ii) the payment and satisfaction in full of all of the Adar Debt and the obligations owing by Minera to Adar, together with all interest and other liabilities.

(b) This Agreement may be terminated at any time prior to Closing as follows:

(i) by mutual written consent of the Sellers and the Purchaser;

(ii) by either the Sellers or the Purchaser if the Closing has not occurred on or before the Outside Date; provided, however, that a party may not exercise

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such termination right if they are in material breach of their obligations under this Agreement;

(iii) by the Sellers, if the Purchaser fails to fulfill any condition set forth in Section 3.2 by the Outside Date and failure has not been waived by the Sellers or cured by the Outside Date;

(iv) by the Purchaser, if the Sellers fail to fulfill any condition set forth in Section 3.1 by the Outside Date and such failure has not been waived by the Purchaser or cured by the Outside Date; or

(v) by any of the parties, if the conditions set forth in Section 3.3 have not been satisfied by the date specified therein or, if not specified, by the Outside Date.

ARTICLE 6

MISCELLANEOUS

6.1 Notices

(a) Any notice or other communication required or permitted to be given hereunder shall be in writing and shall be transmitted by e-mail, addressed as follows:

(i) if to the Sellers:

Premier Silver Corp.