Toronto, Ontario--(Newsfile Corp. - September 21, 2026) - Excellon Resources Inc. (TSXV: EXN) (OTCQB: EXNRF) (FSE: E4X2) ("Excellon" or the "Company") is pleased to report results from the ongoing drill program at its 100%-owned Mallay Silver-Lead-Zinc Mine ("Mallay") in central Peru. Results from the Isguiz vein confirm grade and width continuity below the 4090 Level, supporting planning for deeper mine development. Drilling has also intersected wide zones of silver-lead-zinc mineralization on both sides of Isguiz, outside the current Mineral Resource Estimate and immediately adjacent to development already planned for the vein. Drill results reported herein cover 15 holes totalling approximately 4,400 metres. The Company has drilled approximately 9,000 metres to-date and has transitioned to drilling high-priority step-out targets for which assays are pending or which will be reported separately.

Highlights:

Isguiz Vein - High-Grade Core, Grade and Width Continuity Below the 4090 Level (see Figures 1, 3, and 4)

Relevance for Near-Term Mine Planning: Results will inform development, mine planning and scheduling below the 4090 Level, where the Company is planning a transition to more productive, mechanized mining. Rehabilitation of the 400 Ramp, the primary access to this area, is underway and the Company expects to incorporate these results into an updated mine plan and schedule targeted for year-end.

• MLL26-010: 5.00 m @ 255 g/t Ag, 2.39% Zn and 3.02% Pb (398 g/t AgEq), including 3.40 m @ 290 g/t Ag, 3.43% Zn and 4.33% Pb (495 g/t AgEq) - highest-grade Isguiz intercept returned to-date, confirming strong grade and width continuity in Clavo 6.
• MLL26-004: 12.55 m @ 96 g/t Ag, 2.18% Zn, 0.65% Pb (178 g/t AgEq), including 4.00 m @ 166 g/t Ag, 1.37% Zn, 1.20% Pb (236 g/t AgEq) - this intercept provides depth continuity below the 4090 Level.
• MLL26-011: 2.3 m @ 248 g/t Ag, 0.86% Zn, 1.74% Pb (314 g/t AgEq) - intersected in the Maria vein, a structure in the footwall of the Isguiz vein, approximately 280 m below the 4090 Level, within a broader 11.1 m interval grading 115 g/t AgEq - the deepest mineralization returned in the program thus far.
• MLL26-009: 4.00 m @ 138 g/t Ag, 3.80% Zn, 1.04% Pb (279 g/t AgEq) - Isguiz vein intersected approximately 140 m below 4090 Level, flanked by 5.45 m of footwall calc-silicate mineralization (87 g/t AgEq) and 2.75 m of hangingwall mineralization grading 118 g/t Ag, 4.53% Zn, 3.33% Pb (334 g/t AgEq).
• MLL26-015: 4.30 m @ 137 g/t Ag, 5.22% Zn, 1.72% Pb (337 g/t AgEq), within a wider 11.7 m interval grading 166 g/t AgEq. The hole also intersected 0.7 m of the Isguiz vein grading 76 g/t Ag, 7.06% Zn and 4.58% Pb (398 g/t AgEq).

Calc-Silicate System - A Wide Mineralized Zone Flanking Isguiz, and Outside the Current Resource Estimate (see Figures 2 and 5) - Additional Mineralization Around Isguiz and in Other Structures

Relevance for Near-Term Mine Resource Planning: Drilling has identified silver-lead-zinc mineralization flanking both sides of the Isguiz vein, in zones wider than Isguiz vein mineralization. This material sits outside Mallay's current Mineral Resource Estimate and adjacent to development planned over the next three years. The calc-silicate system will be assessed for inclusion in future updates to the Mallay geological and resource models and, where grade and continuity permit, into future mine planning. Calc-silicate zones, by association, are drilled with each hole targeting the Isguiz Vein structure. Leading intercepts from this system, excluding the higher-grade Isguiz core, include:

• MLL26-006: 11.4 m @ 69 g/t Ag, 5.43% Zn, 1.32% Pb (267 g/t AgEq) - contiguous to Isguiz Vein - the widest calc-silicate intercept returned to-date.
• MLL26-005: 7.7 m @ 50 g/t Ag, 1.99% Zn, 0.78% Pb (129 g/t AgEq) - including 0.75 m @ 184 g/t Ag, 5.78% Zn, 2.87% Pb (428 g/t AgEq), of calc-silicate mineralization, passing directly into 6.65 m of the Isguiz vein grading 97 g/t Ag, 2.97% Zn, 2.10% Pb (237 g/t AgEq) - over 14 m of continuous mineralization.

The 15 holes reported in this release were drilled from two underground drill chambers on the 4090 level and tested Clavos 3 and 6, the two mineralized shoots that are important for near-term mine planning. The objective is to confirm mineralization grade and width ahead of development, and to test continuity of the vein and contiguous mineralization below the current lowest operating level. A plan view of drill hole locations and section lines is shown in Figures 3 and 5.

Shawn Howarth, President and Chief Executive Officer, commented: "Our priority at Mallay is to establish deeper access where we expect to transition toward more productive, mechanized mining. These results support our planning for deeper development at Mallay by confirming grade and width continuity below the 4090 Level. Just as importantly, we are intersecting additional silver-lead-zinc mineralization outside our current resource and alongside development we already plan to undertake. The opportunity is to expand the resource base around the areas we are already working to access, with further drilling and evaluation determining its potential contribution to future mine plans."

Figure 1: 2026 Drill Program - Longitudinal Projection of the Isguiz Vein Showing 2026 Drill Intercepts (Looking East).

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Figure 2: Calc-Silicate (CCS) Alteration: Surrounding Isguiz Vein Mineralization (Looking East).

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Figure 3: Plan view of reported 2026 drill holes and underground workings, showing section lines A-A′ and B-B′.

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Figure 4: Section A-A′ showing selected drill intersections and the interpreted Isguiz, Maria and Maricruz vein systems.

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Figure 5: Section B-B′ showing Isguiz and adjacent Calc-silicate mineralization in holes MLL26-004, MLL26-005 and MLL26-006.

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Ongoing Exploration - Step-Out Drill Targets Defined, Drilling Underway

Drilling continues across four priority step-out targets over the next six months. The program is designed to move sequentially outward from areas already drilled, into adjacent structures that have not been drill-tested in the current program (see Figure 6). The area now being tested below the Isguiz vein extends approximately 700 metres along strike and 400 metres down-dip and encompasses the down-plunge projections of Clavos 2, 3, 6 and continues southward to Clavo 5. Step-out drilling also includes the Rosa vein system, interpreted as a potential structural equivalent of Isguiz on the western limb of the Mallay anticline.

Figure 6: Mallay priority step-out drill targets and existing underground infrastructure.

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2026 Isguiz Drill Results

Table 1: Isguiz Drill Results, MLL26-001 to MLL26-015

Intervals logged as CCS Footwall and CCS Hangingwall are calc-silicate-hosted mineralization flanking the Isguiz vein, in sandstone and limestone lithologies respectively.

All intervals are reported as drill core lengths. True widths vary as holes are drilled in fans from underground drill chambers but generally approximate 80% of core length. Silver-equivalent (AgEq) is calculated with prices used in the February 2026 Mallay Mineral Resource Estimate (US$30/oz Ag, US$1.00/lb Pb and US$1.35/lb Zn). Gold is not included and metallurgical recoveries are not applied. AgEq is provided for comparative purposes only.

Qualified Person

The technical information herein has been reviewed and approved by William McGuinty (P. Geo.), a Qualified Person as defined by National Instrument 43-101. Mr. McGuinty is a consultant and technical advisor to Excellon.

Sample Management

Core is collected by the drill contractor and placed in plastic core boxes of 1 m length, strapped and delivered from the drill location to the core logging facility. Upon entry, box numbers and metreage blocks are checked for errors. Both core and geotechnical logging are undertaken using industry standard logging software. During logging, and within the range of sampled intervals, pieces of the core are weighed by immersion method to obtain density values and subsequently replaced.

For sampling, the core logger traces a cut line on the core at the top of the bedding ellipsoid, and sample intervals are marked using a sample boundary line and directional arrows. Core intervals are marked in a range between 0.5 m to 1.0 m, respecting important contacts. In the cutting room, each interval of core is cut using a diamond-bladed circular saw along the cut line within the sample interval. The two sides of the cut core are replaced in the box in their original position. The core is returned to the core logger who affixes the sample number at the centre of the appropriate sample interval and removes the 'top' half of the cut core to a sample bag marked with the sample tag number and inserts a second identically numbered sample tag in the bag and also marks the bag. At this time, Quality Control and Quality Assurance samples are entered into the sample stream. A blank, duplicate or mineral standard is inserted into the sample stream at a rate of 1 in every 10 samples to be submitted.

The Mallay analytical lab is currently preparing all Mallay samples for assay. At the lab, incoming samples are recorded, dried and crushed using a jaw crusher. A 250 gram aliquot is split and pulverized to the size standard required by the external analytical lab. Coarse reject samples are marked and stored, and prepared pulps are packaged for shipment using their original sample tags. QA/QC samples requiring crushing and pulverizing are prepared at the Mallay lab.

Samples are sent to, and analyzed, in Lima, Peru by ALS Global using their AA-Au24 and Me-ICP61b methods. Silver results exceeding the upper detection limit of the Me-ICP61b method are re-assayed using the Ag-GRA21 gravimetric method. Assay results are only reported once certified results are received and after internal QA/QC procedures have been reviewed.

Table 2 - Location of Reported Holes

Drill hole collar position, dip and azimuth are surveyed by Mallay Mine surveyors

Cautionary Note Regarding Mineral Resources and Exploration Results

The Company has not completed a preliminary economic assessment, pre-feasibility study or feasibility study on the Mallay Mine and has not demonstrated the economic viability of a restart of mining operations. The Company's decision to restart and to advance development at Mallay is not based on a technical study of mineral reserves demonstrating economic and technical viability, and as a result there is increased uncertainty and multiple technical and economic risks of failure associated with the restart. References in this news release to mine planning, development and mining methods describe the Company's current plans and expectations and do not constitute a production decision or production guidance.

Drill results disclosed in this news release are exploration results and are not mineral resources or mineral reserves. The Company has not disclosed mineral reserves at Mallay, and mineral resources that are not mineral reserves do not have demonstrated economic viability. Calc-silicate-hosted mineralization described in this news release is not included in the Mallay mineral resource estimate, and there is no assurance that it will be included in any future mineral resource estimate or that it will prove to be economically mineable. Information regarding mineral resources at Mallay is set out in the technical report prepared by SGS Geological Services with an effective date of February 18, 2026, available under the Company's profile on SEDAR+.

About Excellon Resources Inc.

Excellon Resources is focused on advancing the restart of its fully permitted, past-producing Mallay Silver-Lead-Zinc Mine in Peru, positioning the Company as a near-term silver producer. Following its February 2026 independent mineral resource estimate at Mallay, Excellon is advancing restart planning and near-mine growth, while also advancing the adjacent Tres Cerros Gold-Silver Exploration Property in Peru. The Company also holds the Kilgore Project, an advanced gold exploration project in Idaho, and the Silver City Project, a high-grade epithermal silver district in Saxony, Germany. Additional details on Excellon's properties can be found at www.excellonresources.com.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

All statements, other than statements of historical fact, contained, referenced or incorporated by reference in this news release constitute "forward-looking statements" and "forward-looking information" (collectively, "forward-looking statements") within the meaning of applicable Canadian and United States securities legislation. Generally, these forward-looking statements can be identified by the use of forward-looking terminology such as "advance", "anticipated", "believe", "continue", "expect", "focused", "future", "may", "opportunity", "plan", "potential", "subject to", "will", and similar expressions intended to identify forward-looking statements.

Forward-looking statements in this news release include, but are not limited to, statements regarding: the completion, scope, timing, cost and results of the 2026 drill program at Mallay, including the number of metres to be drilled and the targets to be tested; the timing of receipt and disclosure of pending assay results; the interpretation of drill results and the continuity of grade and width of the Isguiz vein below the 4090 Level; the extent, continuity, grade and potential economic significance of calc-silicate-hosted mineralization flanking the Isguiz vein; the incorporation of drill results into the Mallay geological and mineral resource models and into future mine planning; the timing and content of an updated mine plan and schedule for Mallay, including the Company's expectation of completing such a plan by year-end 2026; the timing of any future mineral resource estimate update; the ability to access and mine mineralized material below the 4090 Level; the timing and completion of rehabilitation of the 400 Ramp and the Company's planned transition to more productive, mechanized mining methods; the results of downhole electromagnetic surveying and the targeting of deeper and offset structures; the extent of the area being tested by step-out drilling and the interpretation of the Rosa vein system as a potential structural equivalent of the Isguiz vein; the potential of the Veta María, Veta Rosa, Pierina and Periclinal structures and of Clavo 5 and Clavo 8; the requirement for, and timing of, additional underground development and drill chamber construction to access planned drill platforms; and the Company's broader strategic objectives at Mallay and across its portfolio.

Although the Company believes that such statements are reasonable, it can give no assurance that such expectations will prove to be correct, and any forward-looking statements by the Company are not guarantees of future actions, results or performance. Forward-looking statements are based on assumptions, estimates, expectations and opinions, which are considered reasonable and represent the Company's best judgment based on available facts as of the date such statements are made. If such assumptions, estimates, expectations or opinions prove to be incorrect, actual and future results may be materially different from those expressed or implied in the forward-looking statements.

Forward-looking statements are inherently subject to known and unknown risks, uncertainties, contingencies and other factors that may cause actual results or performance to differ materially from those expressed or implied by such forward-looking statements. Such factors include, among others: risks relating to the interpretation and application of the technical report and mineral resource estimate; risks that mineral resources are not mineral reserves and do not have demonstrated economic viability; risks relating to the Company's ability to restart operations at Mallay on the timeline anticipated or at all; risks related to exploration, development and mining activities in Peru, including operational, technical, permitting, environmental, community, political and economic risks; risks relating to commodity prices, capital requirements, availability of financing, and general market conditions; risks relating to the performance by third-party contractors and consultants; risks relating to the reliability of sampling, assaying and quality control procedures; and the risks, uncertainties and other factors described in the Company's management's discussion and analysis for the year ended December 31, 2025, and the Company's other continuous disclosure filings available under the Company's profile on SEDAR+.

The forward-looking statements contained in this news release are made as of the date hereof, and the Company disclaims any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or results or otherwise, except as required by applicable law.

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

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Source: Excellon Resources Inc.