Thunder Bay, Ontario--(Newsfile Corp. - September 17, 2026) - Thunder Gold Corp. (TSXV: TGOL) (FSE: Z25) (OTCQB: TGOLF) ("Thunder Gold" or the "Company") is pleased to announce exploration diamond drill results from the Bench Target, at the Company's flagship Tower Mountain Property, 40 kilometres west of Thunder Bay, Ontario.

Highlights:

• TM26-205 identified significant new mineralization east of the current resource pit limit;
• All seven (7) holes intersected mineralization above the current resource cut-off grade in areas previously estimated to be waste;
• Results demonstrate good to excellent correlation to the current resource model;
• TM26-207 and TM26-207A provide twinned hole results indicating minimal variation (less than 5%) over the first 40 metres of both holes and;
• TM26-213 intersected 287.7 metres averaging 0.223 g/t Au, extending the mineralized trend to the southeast.

Holes TM26-201, 205, 206, 207 and 208 were drilled perpendicular to the interpreted Tower Mountain Intrusive Complex ("TMIC") contact probing the eastern extent of the variably brecciated and altered volcanic +/- intrusive horizon hosting the known gold mineralization of the Bench Target. This area was exclusively classified as waste in the 2026 Mineral Resource Estimate ("MRE") due to lack of drill coverage.

Holes TM26-209 and TM26-213 were drilled sub-parallel to the interpreted TMIC contact.

Wes Hanson, President and CEO states, "With the exception of TM26-213, these holes all tested the 150 million tonnes of waste rock within the 2026 MRE pit shell that were not estimated due to insufficient drill coverage. All intervals above the MRE cut-off grade (0.19 g/t Au) offer potential to reduce the waste:ore strip ratio which is already amongst the lowest of our Canadian peer group. The targeted area represents 66% of the total waste included in the 2026 MRE. It is therefore significant that all seven holes intersected intervals above the MRE cut-off grade as these already lie within the current MRE optimized pit shell."

"The most significant mineralization occurs in TM26-205 (121.5 metres averaging 0.376 g/t Au). This mineralization lies 200 metres east of the 2026 MRE resource pit limit, approximately 400 metres from surface. The target is open in all directions. Follow up drilling targeting the up-dip continuity is planned."

"TM26-213 is also significant. Drilled parallel to the eastern TMIC contact, this hole was consistently mineralized from the collar to the end of the hole through an area of sparse drill coverage."

"We continue to operate two (2) drills and warrant exercises have fully funded our remaining drilling. Year-to-date, we have completed 6,600 metres of exploration drilling and 3,795 metres of resource definition drilling. All-in exploration costs for the year are approximately C$250 per metre. We plan to complete an additional 7,500 metres of resource definition drilling prior to year-end and estimate approximately 60 to 70% of that total will be included in the planned MRE update scheduled for year-end."

Table 1.0 provides the location and orientation of the reported holes. Figure 1.0 is a plan view showing the location of the drill holes reported in this news release.

Table 1.0 - Bench Target - Resource Expansion Drilling Location Bearing and Dip

Figure 1.0 Bench Target Resource Expansion Drill Holes - September 2026

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Table 2.0 summarizes the significant results, by primary lithology.

Table 2.0 - Bench Target Resource Expansion Drilling Significant Results

Table 2.0 - Bench Target Resource Expansion Drilling Significant Results (continued)

True Width cannot be estimated due to insufficient information, except where noted.

TM26-205 Results

Figure 2.0 is a cross section parallel to hole TM26-205 showing the location of the new target discovered 200 metres east of the current resource pit shell. Mineralization is continuous along the entire 121.5 metre interval (Reference Table 3.0).

TM26-205 also intersected the high grade core of the Bench Target near surface, intersecting 158.6 metres averaging 0.545 g/t Au within the brecciated and variably altered host rocks, including 54.0 metres averaging 1.088 g/t Au from surface to the interpreted limit of the Bench trend (Reference Table 4.0). This intercept lies entirely within the current pit limit constraining the 2026 MRE.

The initial 158.6 metres of TM26-205 demonstrates good to excellent correlation to the current resource model, verifying the predictive accuracy in terms of both location and tenor of mineralization. The remaining 444.4 metres demonstrates poor correlation with the current resource model exclusively as a result of a lack of drill coverage which limits the predictive accuracy of the current resource model outside the currently drilled volume (Reference Figure 2.0).

Figure 2.0 - Cross Section TM26-205 (Looking NW) 50 metre Influence

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Tables 3.0 and 4.0 below summarize the individual sample results from TM26-205.

Table 3.0 - TM26-205 - Individual Results From New Target 200 metres East of MRE Pit Limit

Table 4.0 - TM26-205 Individual Results Bench Target - High Grade Core

TM26-213 Results

TM26-213 was drilled to the southeast, sub-parallel to the interpreted trend of the Bench Target towards the 110 Target through an area of sparse drill density. TM26-213 intersected semi-continuous gold mineralization from surface to the end-of-hole returning 589.0 metres averaging 0.195 g/t Au over the entire drill hole. Approximately 50% of the hole lies within the current optimized pit. The remaining 50% of the hole suggests potential to expand the current resource beyond the currently defined optimized pit limit with a 64.5 metre long interval averaging 0.255 g/t Au observed at the current pit limit.

Overall, TM26-213 demonstrates good to excellent correlation with the current resource model, verifying the predictive accuracy in terms of both location and tenor of mineralization. This hole clearly demonstrates the consistency of grade across the main lithological contact between the volcanics and intrusive rocks which occurs at a depth of 291.7 metres.

Figure 3.0 presents a Cross Section View through hole TM26-213.

Figure 3.0 - Cross Section TM26-213 (Looking E) 50 metre Influence

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Table 5.0 presents the individual assay results for the entirety of TM26-213.

Table 5.0 - TM26-213 Individual Results Bench-110 Target

Table 5.0 - TM26-213 Individual Results Bench-110 Target (continued)

Table 5.0 - TM26-213 Individual Results Bench-110 Target (continued)

Table 5.0 - TM26-213 Individual Results Bench-110 Target (continued)

Quality Assurance and Quality Control

Diamond drilling utilizes NQ diameter tooling. The core is received at the on-site logging facility where it is, photographed, logged for geotechnical, physical properties and geological data. Samples are identified, recorded, and cut in half by wet diamond saw. Half the core is sent for assay at an accredited laboratory with the remaining half core stored on site. A standard sample length of 1.5 meters is typically employed, varying only at major lithological contacts.

Certified standards and blanks are randomly inserted into the sample stream and constitute approximately 10% of the sample stream. Certified standards and blank performance is monitored with any failures evaluated and investigated to determine if said failure is a result of error during submission. Any unexplained failures are identified and the five samples preceding and following the failure are re-assayed. Commencing in 2026, duplicate pulps are prepared at a rate of 1 in every 20 samples. The duplicate pulps are sent to a second independent analytical facility for analyses.

Activation Laboratories Ltd., Thunder Bay, Ontario, ISO/IEC 17025:2017 is the primary independent analytical service provider.

AGAT Laboratories, Thunder Bay, Ontario, ISO/IEC 17025:2017 is the secondary, independent analytical facility.

Samples are, received, dried, crushed to 80% passing 2.0 mm. A 250-gram sample is split and pulverized. Samples are analyzed for gold using a 30-gram lead collection fire assay fusion (FA) with an atomic absorption (AAS) finish. All assay results greater than 5.0 g/t Au are re-assayed using a gravimetric analysis. All assays greater than 30.0 g/t Au are re-assayed using screen metallics where a representative 1000-gram sample is split sieved at 149µm. Assays are performed on the entire +149 µm fraction and two splits of the -149 µm fraction. A final assay is calculated based on the weight of each size fraction.

Qualified Person

Technical information in this news release has been reviewed and approved by Wes Hanson, P.Geo., President and CEO of Thunder Gold Corp., who is a Qualified Person under the definitions established by NI 43-101.

About the Tower Mountain Gold Property

The 7,625-hectare, 100%-owned Tower Mountain Property is beside the Trans-Canada highway, 40-km west of Thunder Bay, Ontario (pop. 120,000). Gold mineralization occurs in variably brecciated and altered rocks surrounding the calc-alkalic Tower Mountain Intrusive Complex ("TMIC"). Drilling to date has established an initial mineral resource parallel to the western contact of the intrusion representing approximately 25% of the TMIC halo.

The MRE has an effective date of January 19, 2026. A Technical Report titled " NI 43-101 Technical Report for the 2026 Mineral Resource Estimate on the Tower Mountain Project, Ontario, Canada." is available on the Company's website at www.thundergoldcorp.com and on SEDAR+ (www.sedarplus.ca) under the Company's Issuer profile.

The Report was prepared by Charley Murahwi, P.Geo., FAusIMM.; William Lewis, P.Geo., Tudorel Ciuculescu, P.Geo., and Richard Gowans, P.Eng., all of Micon International Limited ("Micon"), Toronto, Ontario, Canada. The Report was prepared in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") and CIM Definition Standards of Mineral Resources and Mineral Reserves.

The MRE is summarized as follows:

Tower Mountain Mineral Resource Estimate - January 19, 2026

Notes:

1. The effective date of this MRE is January 19, 2026.
2. Messrs. William Lewis, P.Geo., Charley Murahwi, P.Geo., FAusIMM, and Tudorel Ciuculescu, P.Geo. from Micon International Limited are the Qualified Persons (QPs) responsible for this MRE.
3. The MRE has been classified in the Indicated and Inferred categories. At this time, there are no Measured resources at the Tower Mountain Project.
4. The calculated gold cut-off grade is 0.19 g/t Au.
5. An average specific gravity (SG) value of 2.77 g/cm³ was used.
6. The MRE used economic assumptions for open pit mining. The following economic parameters were used for generating the cut-off grade: a gold price of US$3,000/oz, 80% recovery, open pit mining cost of US$3.0/t, processing costs of US$8.0/t, general and administration cost of US$3.5/t, transportation cost of US$2.5/oz of gold, and a royalty of 3%.
7. The open pit used slope angles of 30° in overburden and 50° in fresh rock.
8. The block model is orthogonal and has a parent block size of 5 m x 5 m x 5 m, with minimum sub-block size of 2.5 m x 2.5 m x 2.5 m.
9. The open pit optimization used a re-blocked size of 10 m x 10 m x 10 m.
10. The mineral resources described above have been prepared in accordance with the current Canadian Institute of Mining, Metallurgy and Petroleum Standards and Practices.
11. Numbers have been rounded to the nearest million tonnes and nearest thousand ounces. Differences may occur in totals due to rounding.
12. Mineral Resources are not Mineral Reserves as they do not have demonstrated economic viability. The quantity and grade of reported Inferred Mineral Resources are uncertain in nature and there has been insufficient exploration; however, it is reasonably expected that a significant portion of Inferred Mineral Resources could be upgraded into Indicated Mineral Resources with further exploration.
13. Micon QPs have not identified any legal, political, environmental, or other relevant factors that could materially affect the potential development of the mineral resources and of the estimate.

The remaining 75% of the TMIC halo demonstrates similar geology, alteration, and geophysical signatures and is untested by drilling.

A second gold trend, identified in 2026, outcrops at surface and is continuously mineralized over a 100-metre width. This gold mineralization occurs within Timiskaming-type conglomerates that have been traced for over 5.0 kilometres along a southwest trend paralleling the Thunder Lake Fault. The Company believes both targets offer opportunities to materially increase the total resource through systematic drilling.

About Thunder Gold Corp.

Thunder Gold is advancing the Tower Mountain project in Thunder Bay, Ont. -- an emerging gold system with the scale, consistency and quality to support a long-life, open-pit operation. Results from the disciplined drill programs have consistently reinforced confidence in the continuity and predictability of the discovery while highlighting significant potential for expansion across multiple zones of the Tower Mountain intrusive complex. With industry-leading drilling costs, existing infrastructure and a skilled local work force, Tower Mountain represents a rare combination of size, scalability and cost-effective growth.

At Thunder Gold, our vision is clear: to unlock a discovery that has the potential to become a transformational gold project, delivering long-term value for shareholders while contributing to the future of Canada's mining industry.

For more information about the Company please visit: www.thundergoldcorp.com.

On behalf of the Board of Directors,
Wes Hanson, P.Geo., President and CEO

NEITHER THE TSXV NOR ITS REGULATION SERVICES PROVIDER (AS THAT TERM IS DEFINED IN THE POLICIES OF THE TSXV) ACCEPTS RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF THIS RELEASE.

The information contained herein contains "forward-looking information" and "forward-looking statements" within the meaning of applicable securities legislation (collectively, "forward-looking statements"). Forward-looking statements relate to information that is based on assumptions of management, forecasts of future results, and estimates of amounts not yet determinable. All statements, other than statements of historical fact, are forward-looking statements and are based on predictions, expectations, beliefs, plans, projections, objectives and assumptions made as of the date of this news release, including the Company's plans regarding exploring its mineral exploration properties; anticipated results of geophysical surveys, drilling programs, geological interpretations and potential mineral recovery. Any statement that involves discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as "expects", or "does not expect", "is expected", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking statements.

Forward-looking statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ from those reflected in the forward-looking statements, including, without limitation: risks related to failure to obtain adequate funding on a timely basis and on acceptable terms; risks related to the outcome of legal proceedings; political and regulatory risks associated with mining and exploration; risks related to the maintenance of stock exchange listings; risks related to environmental regulation and liability; the potential for delays in exploration or development activities or the completion of feasibility studies; the uncertainty of profitability; risks and uncertainties relating to the interpretation of drill results, the geology, grade and continuity of mineral deposits; risks related to the inherent uncertainty of production and cost estimates and the potential for unexpected costs and expenses; results of prefeasibility and feasibility studies, and the possibility that future exploration, development or mining results will not be consistent with the Company's expectations; risks related to the gold price and other commodity price fluctuations; and other risks and uncertainties related to the Company's prospects, properties and business detailed elsewhere in the Company's disclosure record. Should one or more of these risks and uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described in forward-looking statements. Investors are cautioned against attributing undue certainty or reliance on forward-looking statements. These forward-looking statements are made as of the date hereof and the Company does not assume any obligation to update or revise any forward-looking statements, other than as required by applicable law, to reflect new information, events or circumstances, or changes in management's estimates, projections or opinions. Actual events or results could differ materially from those anticipated in the forward-looking statements or from the Company's expectations or projections.

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