Thunder Mountain Gold Inc: Form 10-K for the period ended Dec 31, 2025

Company History

Thunder Mountain Gold, Inc. (a predecessor entity) was originally incorporated under the laws of the State of Idaho on November 9, 1935, under the name of Montgomery Mines, Inc. In April 1978, a controlling interest in the Montgomery Mines Corporation was obtained by a group of the Thunder Mountain property holders who then changed the corporate name to Thunder Mountain Gold, Inc. with the primary goal to further develop their holdings in the Thunder Mountain Mining District, Valley County, Idaho.

Change in Situs and Authorized Capital

On December 10, 2007, articles of incorporation were filed with the Secretary of State in Nevada for Thunder Mountain Gold, Inc., a Nevada Corporation. The Directors of Thunder Mountain Gold, Inc. (Nevada) were the same as for Thunder Mountain Gold, Inc. (Idaho).

On January 25, 2008, the shareholders approved the merger of Thunder Mountain Gold, Inc. (Idaho) with Thunder Mountain Gold, Inc. (Nevada), which was completed through a share-for-share exchange of common stock. The terms of the merger were such that the Nevada Corporation was the surviving entity (now the "Company"). The Company has 200,000,000 shares of common stock authorized with a par value of $0.001 per share and 5,000,000 shares of preferred stock authorized with a par value of $0.0001 per share.

The corporate structure of the Company is as follows: the Company owns 100% of the outstanding stock of Thunder Mountain Resources, Inc., a Nevada Corporation ("TMRI"); TMRI owns 100% of the outstanding stock of South Mountain Mines, Inc., an Idaho Corporation ("SMMI"); SMMI owns 75% of Owyhee Gold Territory, LLC ("OGT").

We have no patents, licenses, franchises or concessions which are considered by the Company to be of importance. The business is not of a seasonal nature. Since the potential products are traded in the open market, we have no control over the competitive conditions in the industry. There is no backlog of orders.

There are numerous Federal and State laws and regulations related to environmental protection, which have direct application to mining and milling activities. The more significant of these laws deal with mined land reclamation and wastewater discharge from mines and milling operations. We do not believe that these laws and regulations as presently enacted will have a direct material adverse effect on our operations. The Company employs one full-time officer and three part-time.

Subsidiary Companies

On May 21, 2007, the Company filed Articles of Incorporation with the Secretary of State in Nevada for Thunder Mountain Resources, Inc., a wholly owned subsidiary of Thunder Mountain Gold, Inc. The financial information for the new subsidiary is included in the consolidated financial statements.

On September 27, 2007, TMRI completed the purchase of all the outstanding stock of South Mountain. On November 8, 2012, South Mountain and Idaho State Gold Company II LLC ("ISGC or ISGC II") formed OGT (aka Owyhee Gold Trust, LLC), a wholly-owned subsidiary of SMMI.

On November 4, 2016, SMMI became Managing Member and controlling Member of OGT, through a judicially approved settlement agreement with ISGC. The Company's wholly owned subsidiary SMMI is the sole manager of the South Mountain Project in its entirety through a separate Mining Lease with Option to Purchase ("Lease Option") with the Company's majority-owned subsidiary OGT. SMMI has an option to purchase the South Mountain mineral interest for a capped $5 million, less net returns royalties paid through the date of exercise. The Lease Option expires in November 2026. If SMMI exercises the option, the option payment of $5 million, less advance royalties, will be distributed 100% by OGT to OGT's minority member, ISGC II Under the Lease Option, SMMI pays an advance of $5,000 net returns royalty to OGT annually on November 4 which is distributed to OGT's minority member, ISGC II.

Current Operations

On September 17, 2024, the Company remodeled its geological data and historical reports for the South Mountain Project utilizing acquired induced polarization (IP) data, airborne magnetic geophysical survey data, and copper-in-soil geochemical survey (Geochem) results. Based on this analysis, the Company staked additional unpatented mining claims (lode claims), covering approximately 260 acres of Bureau of Land Management (BLM) land.

On January 27, 2025, the Company announced a strategic partnership with Swiss-based MFD Investment Holdings SA ("MFD"). The letter agreement signed outlines that MFD will provide additional funding, contributing $1,000,000 in project-related expenditures as well as providing technical support for project development. This partnership adds additional financial strength in advancing South Mountain's technical and economic studies. The letter agreement is in the form of an option, whereby THMG grants an option to MFD to earn an interest in its South Mountain Project pursuant to which MFD shall have the right, but not the obligation, to complete certain requirements in return for the acquisition of a 10% interest in the Project. As of December 31, 2025, the Company has received $203,498 from MFD for project-related reimbursements, recorded as a reduction to exploration expenses.

During 2025, the Company continued advancing exploration and development activities at the South Mountain Project. The Company's efforts were focused on refining drill targets through updated geophysical modeling and geochemical interpretation.

The Company also continued evaluating exploration opportunities at its Trout Creek Project in Lander County, Nevada. Planned activities include induced polarization geophysics and mobile metal ion geochemical sampling to further define drill targets originally identified through prior exploration programs.

In 2026, the Company intends to conduct core drilling and additional geophysical and geochemical studies at South Mountain to further delineate mineralization and support future technical and economic evaluations.

Costs and Effects of Compliance with Environmental Laws

The Company has accrued $86,380 in reclamation costs regarding the South Mountain Mine project. Various laws and permits require that financial assurances be in place for certain environmental and reclamation obligations and other potential liabilities. Once we undertake any trenching or drilling activities, a reclamation bond and a permit may be required under applicable laws. Currently, we have no obligations for financial assurances of any kind, and are unable to undertake any trenching, drilling, or development on any of our properties until we obtain financial assurances pursuant to applicable regulations to cover potential liabilities.

For the Trout Creek Project Property, there are no permits associated with the property, and there are no processing plants or other available facilities located on the property. There are currently no environmental permits required for exploration work on the property. In the future, a plan of operations may be required by the Bureau of Land Management to conduct exploration and sampling at the property.

Regarding the South Mountain Project Property, the Project is largely on, and surrounded by private land, and as such, the permitting and environmental aspects of the Project are expected to be straightforward. Permits are currently in place for underground and surface exploration and development activities.

Employees

The Company employs two full-time officers, three part-time officers and one administrative staff. It is anticipated that the employees will continue their work with the Company.

Reports to Security Holders

The Company is not required to issue annual reports to security holders other than the annual reports on Form 10-K and the quarterly reports on Form 10-Q, as electronically filed with the SEC. Our annual reports on Form 10-K contain financial information that has been examined and reported on, with an opinion expressed by an independent public or certified public accountant. Electronically filed reports may be accessed at www.sec.gov (http://www.sec.gov). Information may be obtained on the operation of the Public Reference Room by calling the SEC at 1 (800) SEC-0330.

The Company maintains a website where recent press releases and other information can be found. A link to the Company's filings with the SEC is provided on the Company's website: https://www.thundermountaingold.com. The Company makes available free of charge through our website, our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports, when filed or furnished, or as soon as reasonably practicable after we file such material, or furnish it to, the SEC.

Investor inquiries or requests for copies of filings may be directed to the Company at:

Thunder Mountain Gold, Inc.

11770 W. President Drive., Ste. F

Boise, ID 83713

(208) 658-1037

Attn: Chief Financial Officer

Our mineral resources are subject to uncertainty and may not convert to reserves. Information concerning our mining properties in this Annual Report on Form 10-K has been prepared in accordance with subpart 1300 of Regulation S-K. These requirements differ significantly from prior SEC disclosure standards. Subpart 1300 requires disclosure of mineral resources in addition to mineral reserves. Mineral resources do not have demonstrated economic value and are subject to further exploration and development. No assurance can be given that mineral resources will be converted into mineral reserves. Inferred resources have more uncertainty than Measured or Indicated as the estimation parameters assume mineralized continuity over greater distances which may or may not accurately reflect the actual mineralization. Investors are cautioned not to assume that any part or all of the Inferred Resource exists or is economically or legally mineable.

We have no income and limited resources and will require additional capital to sustain operations. The Company's viability depends on its ability to secure capital for future exploration and working capital needs. The primary means of funding anticipated for sustaining operations will be through the issuance of debt, the sale of our common stock, the sale of property interests, or strategic partnerships, with the eventual profitable development of mining properties. The availability of funds from these sources is not guaranteed. Failure to successfully raise additional capital may impede property development and limit our operations.

As of December 31, 2025, the Company had a cash balance of $2,592,167. During the year ended December 31, 2025, the Company used $1,609,019 in net cash in operating activities and generated $3,775,000 in net cash from financing activities, primarily from private placement offerings. While current cash resources are expected to support near-term operating activities, the Company does not generate revenue from operations and expects to continue incurring operating losses as it advances exploration programs.

The Company will require additional capital to fund ongoing exploration activities, maintain mineral claims, satisfy lease and regulatory obligations, and support general corporate purposes beyond its current funding horizon. There can be no assurance that additional financing will be available on acceptable terms, or at all. If adequate capital is not obtained when required, the Company may be required to reduce or suspend exploration activities, relinquish mineral claims, dispose of assets, or otherwise limit its operations. In such event, investors could lose all or a substantial portion of their investment.

We have no proven reserves. We have no proven reserves at any of our properties. We have identified measured, indicated, and inferred mineral resources at the South Mountain Project and assay samples at certain other exploration properties; however, no proven or probable mineral reserves have been established. Without proven reserves, there can be no assurance that our properties will generate revenue.

Our exploration efforts may be adversely affected by metals price volatility causing us to cease exploration efforts. The success of our exploration efforts depends significantly on prevailing metal prices, which are affected by numerous factors including: 1) expectations for inflation; 2) investor speculative activities; 3) relative exchange rates of the U.S. dollar; 4) global and regional demand and production; 5) political and economic conditions; and 6) production costs in major producing regions. These factors are beyond our control and are difficult for us to predict.

There is no guarantee that current favorable prices for metals and other commodities will be sustained. If the market prices for these commodities weaken, we will temporarily suspend or cease exploration efforts.

Our business faces significant risks by information technology disruptions by cyber-attacks. The frequency and sophistication of cybersecurity incidents, such as the installation of malicious software and unauthorized data access, are on the rise. Our operations depend, in part, on how well we and our vendors protect networks, equipment, IT systems and software against damage from several threats, including, but not limited to natural disasters, intentional damage and destruction, fire, power loss, hacking, computer viruses, vandalism, theft, malware, ransomware and phishing attacks. Any of these and other events could result in IT system failures, delays, a material disruption of our business or increases in capital expenses. Our operations also depend on the timely maintenance, upgrade and replacement of networks, equipment and IT systems and software, as well as preemptive expenses to mitigate the risks of failures.

Moreover, the significance of our information technology systems and networks will escalate with a growing number of our employees working remotely. Additionally, should one of our service providers falters without prompt replacement, our ability to effectively manage outsourced functions could be compromised. While we believe we have implemented appropriate measures to mitigate these risks, the unpredictable nature and scope of IT disruptions could leave us vulnerable to system manipulation, financial losses from remedial actions, or other adverse impacts on our financial condition and operational results.

Our mineral exploration efforts may not be successful. Mineral exploration is highly speculative. It involves many risks and often does not produce positive results. Even if we find a valuable mineral deposit, it may take many additional years or more before production is possible because of the need for additional detailed exploration, pre-production studies, permitting, financing, construction and start up. During that time, it may not be economically feasible to produce those minerals. Establishing ore reserves requires us to make substantial capital expenditures and, in the case of new properties, to construct mining and processing facilities. As a result of these costs and uncertainties, we may not be able to develop any potentially economic mineral deposits.

We face strong competition from other mining companies for the acquisition of new properties. If we do find an economic mineral reserve and put it into production, we need to continually seek to find new properties. In addition, there is a limited supply of desirable mineral lands available in the United States or elsewhere where we would consider conducting exploration activities. Because we face strong competition for new properties from other exploration and mining companies, some of whom have greater financial resources than we do, we may be unable to acquire attractive new mining properties on terms that we consider acceptable.

Mining operations may be adversely affected by risks and hazards associated with the mining industry. Mining operations involve a number of risks and hazards including: 1) environmental hazards; 2) political and country risks; 3) industrial accidents; 4) labor disputes; 5) unusual or unexpected geologic formations; 6) high wall failures, cave-ins or explosive rock failures, and 7) flooding and periodic interruptions due to inclement or hazardous weather conditions. Such risks could result in: 1) damage to or destruction of mineral properties or producing facilities; 2) personal injury; 3) environmental damage; 4) delays in exploration efforts; 5) monetary losses, and; 6) legal liability.

We have no insurance against any of these risks. To the extent we are subject to environmental liabilities, we would have to pay for these liabilities. Moreover, in the event that we ever become an operator of a mine and are unable to fully pay for the cost of remedying an environmental problem, should it occur, we might be required to suspend operations or enter into other interim compliance measures.

We must limit our exploration due to capital constraints. Because our Company is small and does not have much capital, we must limit the time and money we expend on exploration of interests in our properties. This may prevent us from realizing any revenues, thus reducing the value of the stock. In particular, we may not be able to: 1) devote the time we would like to explore our properties; 2) spend as much money as we would like to exploring our properties; 3) rent the quality of equipment or hire the contractors we would like to have for exploration; and 4) have the number of people working on our properties that we would like to have. By limiting our operations, it may take longer to explore our properties. There are other larger exploration companies that could and may spend more time and money exploring the properties that we have acquired.

We will have to suspend our exploration plans if we do not have access to all the supplies and materials we need. Competition and unforeseen limited sources of supplies in the industry could result in occasional spot shortages of supplies. We have not attempted to locate or negotiate with any suppliers of products, equipment or materials. We will attempt to locate products, equipment and materials after we have conducted preliminary exploration activities on our properties. If we cannot find the products and equipment we need in a timely manner, we will have to delay or suspend our exploration plans until we do find the products and equipment we need.

We face substantial governmental regulation, economic and environmental risks, which could prevent us from exploring or developing our properties. Our business is subject to extensive federal, state and local laws and regulations governing mining exploration development, production, labor standards, occupational health, waste disposal, use of toxic substances, environmental regulations, mine safety and other matters. New legislation and regulations may be adopted at any time that results in additional operating expenses, capital expenditure or restrictions and delays in the exploration, mining, production or development of our properties.

Inflationary pressures, economic tariffs and rising exploration costs may impact on our ability to maintain current operations, obtain favorable equipment prices and secure financing terms. Inflationary rises could impede our ability to raise additional capital, increasing the risk of business disruptions.

Supplies and equipment needed for exploration may not always be available. If the Company is unable to secure raw materials and exploration supplies, it may have to delay anticipated business operations. Competition, the imposition of tariffs and other trade sanctions, and unforeseen limited sources of supplies needed for the Company's proposed exploration work could result in occasional shortages of supplies of certain products, equipment, or materials. There is no guarantee the Company will be able to obtain certain products, equipment and/or materials as and when needed, without interruption, or on favorable terms, if at all. Such delays could affect the Company's anticipated business operations and increase expenses.

If we fail to maintain effective internal controls over financial reporting, we could experience material weaknesses, inaccurate financial reporting, regulatory scrutiny, or harm to our reputation. Our internal control systems provide only reasonable assurance that fraud or errors will be prevented or detected.

Regulations and pended legislation governing issues involving climate change could result in increased operating costs, which could have a material adverse effect on the Company's business. A number of governments or governmental bodies have introduced or are contemplating legislative and/or regulatory changes in response to concerns about the potential impact of climate change. Legislation and increased regulation regarding climate change could impose significant costs on the Company, on its future venture partners, if any, and on its suppliers, including costs related to increased energy requirements, capital equipment, environmental monitoring and reporting, and other costs necessary to comply with such regulations. Any adopted future climate change regulations could also negatively impact the Company's ability to compete with companies situated in areas not subject to such limitations. Given the emotional and political significance and uncertainty surrounding the impact of climate change and how it should be dealt with, the Company cannot predict how legislation and regulation will ultimately affect its financial condition, operating performance, and ability to compete. Furthermore, even without such regulation, increased awareness and any adverse publicity in the global marketplace about potential impacts on climate change by the Company or other companies in its industry could harm the Company's reputation. The potential physical impacts of climate change on its operations are highly uncertain and could be particular to the geographic circumstances in areas in which the Company operates and may include changes in rainfall and storm patterns and intensities, water shortages, changing sea levels, and changing temperatures. These impacts may adversely impact the cost, production, and financial performance of the Company's operations.

There are several governmental regulations that materially restrict mineral exploration. The Company will be subject to the federal regulations (environmental) and the laws of the State of Idaho as the Company carries out its exploration program. The Company may be required to obtain additional work permits, post bonds and perform remediation work for any physical disturbance to the land in order to comply with these laws. While the Company's planned exploration program budgets for regulatory compliance, there is a risk that new regulations could increase its costs of doing business and prevent it from carrying out its exploration program.

The Company recognizes the critical importance of cybersecurity in safeguarding sensitive information, maintaining operational resilience, and protecting stakeholders' interests. The Company currently manages cybersecurity risks by working with third-party IT consultants and utilizing basic security protocols, such as network monitoring and access controls. Management is responsible for identifying, considering, and assessing material cybersecurity risks on an ongoing basis, establishing processes to the best of their ability to ensure that such potential cybersecurity risk exposures are monitored, putting in place reasonably appropriate mitigation measures and maintaining cybersecurity programs. Our cybersecurity programs are under the direction of our CFO with assistance from the management team. Any significant Cyber incidents that they become aware of are reported to the board of directors. The Board of Directors does not have a designated cybersecurity committee, but the Audit Committee receives periodic updates on cybersecurity matters. The Company has not experienced any material cybersecurity incidents to date and there were no material cybersecurity incidents discovered in 2025. Please refer to Item 1A: Risk Factors for further insights into cyber attack-related risks.

Summary

The Company, including its subsidiaries, owns mining rights, claims, and properties in the mining areas of Nevada and Idaho. These include the South Mountain Property in Idaho ("South Mountain Project") and the Trout Creek Property in Nevada ("Trout Creek Project"). The maps below in Figure 1 and Figure 2 show the locations of the properties.

Figure 1 - South Mountain Project Location Map

INDIVIDUAL PROPERTIES - MATERIAL OPERATING PROPERTIES

THE SOUTH MOUNTAIN PROJECT

SPECIAL NOTE TO READERS: The South Mountain Project is a material property as defined by Regulation S-K Subpart 1300 (S-K 1300) issued by the Security and Exchange Commission (SEC). All other properties described in this Annual Report are immaterial under S-K 1300.

Figure 3. Location of South Mountain Project

South Mountain Project Summary Overview

The Company operates the South Mountain Project ("South Mountain" or the "South Mountain Project" or the "Property" or the "Project") comprised of an underground mine and adjacent exploration properties located approximately 70 miles southwest of Boise, Idaho (see Figure 3 above). It is a polymetallic Exploration Stage Property focused on high-grade zinc, silver, gold, and copper. Mineralization was first discovered at South Mountain in 1868, with subsequent mining activity leading to the discovery of the oxidized silver, gold, zinc and lead veins. The Project was intermittently mined from the late 1800s to the late 1960s. According to historical smelter records, approximately 53,642 tons of mineralized material have been mined by previous operators. Because the South Mountain Project is an Exploration Stage property, the Company had no aggregate annual production from the South Mountain Project in the last three years.

The Company owns 100% the South Mountain Project, through its wholly-owned subsidiaries-Thunder Mountain Resources, Inc., South Mountain Mines, Inc. and Thunder Mountain Resources, Inc. The South Mountain Project originally consisted of 17 patented mining claims (approximately 327 acres) located in Owyhee County in southwestern Idaho. After the Company's purchase of the property, it staked an additional 21 unpatented lode mining claims and obtained mineral leases on 489 acres of adjoining private ranch land, and an additional 13 unpatented claims on approximately 260 acres in 2024.

The South Mountain Project is largely located on and surrounded by private land and state of Idaho endowment land. Future agreements with individual private landowners, along with the existing easements and right of ways, may be necessary to establish infrastructure such as roads and power lines. The private land setting greatly simplifies and streamlines the permitting and approval process. Owyhee County approved Conditional use Permits ("CUPs") for the mine site and mill site in 2013. At the County's request, the Company is updating technical information and re-applying for these permits with the County. Both the mine and the mill site are located on private land, and as such, require no other permit authorization for surface disturbance, other than any approvals from the County to further extend and / or update the previously approved CUPs.

Also included in the South Mountain Project area is a 360-acre millsite, not contiguous with the mining claims, which was purchased by THMG in 2013. The millsite is located approximately 6.8 road miles from the main mine area, with access provided by a 1.2-mile haul road between the millsite and Owyhee County South Mountain Road. Plans to construct a mill were approved by Owyhee County in 2013, as described above through the CUPs.

Summary Mineral Resources at End of the Fiscal Year Ended December 31, 2025

For a summary of South Mountain's Mineral Resources at the end of the fiscal year ended December 31, 2025, see Table 1 below.

Reserves

The Company has no proven or probable mineral reserves on any of its properties at the end of the fiscal year ended December 31, 2025.

Property and Location

The South Mountain Project is located approximately 70 miles southwest of Boise, Idaho at Latitude 42° 44' 41.65" North and Longitude 116° 55' 13.48" West (see Figure 3 above). The Project was intermittently mined from the late 1800s to the late 1960s, and its existing underground workings remain intact and well maintained. Historic production, mostly from Anaconda Copper, at the Project has largely come from high-grade massive sulfide zones that remain open at depth and along strike. According to historical smelter records, approximately 53,642 tons of mineralized material has been mined to date. These records also indicate average grades; 14.5% Zn, 11.63 opt Ag, 0.063 opt Au, 2.4% Pb, and 1.4% Cu were mined.

The South Mountain Project mine site is accessible by Highway 95, driving south from the Boise area to Jordan Valley, Oregon, then by traveling southeast approximately 22 miles back into Idaho, via Owyhee County Road, a dirt road improved to within 4 miles of historic mine site. The last 4 miles up the South Mountain Mine Road is unimproved dirt road. The property is accessible year-round to within 4 miles of the property. Snow removal is required to access the property during the winter months, but the property is accessible from May through October without the need for snow removal. There is power distribution within 4 miles of the site. The climate is considered high desert. The Company has water rights on the property, and there is a potable spring on the property that once supplied water to the main mining camp.

The community nearest to the Project is Jordan Valley, Oregon, roughly 24 miles to the northwest of the South Mountain Project area. Jordan Valley hosts a regional population of about 450 and offers limited standard municipal amenities. The nearest major supply center is the city of Nampa, roughly 100 miles northeast of the South Mountain Project area. Commercial air and rail services are both available in Nampa, which is served by the Nampa Municipal Airport and Union Pacific's Northwest Corridor rail line. Ample skilled and unskilled labor can be found in Nampa and the greater Boise-Nampa metropolitan area. There are no onsite personnel currently employed at the property.

Property Ownership

The Company owns 100% of the outstanding stock of Thunder Mountain Resources, Inc., a Nevada Corporation. Thunder Mountain Resources, Inc. owns 100% of the outstanding stock of South Mountain Mines, Inc. (SMMI), an Idaho Corporation. Thunder Mountain Resources, Inc. completed the direct purchase of 100% ownership of South Mountain Mines, Inc. on September 27, 2007, which consisted of 17 patented mining claims (approximately 327 acres) located in Owyhee County in southwestern Idaho. After the purchase, Thunder Mountain Resources staked 21 unpatented lode mining claims and obtained mineral leases on 489 acres of adjoining private ranch land.

The current land package at the South Mountain Project consists of 18 patented mining claims encompassing approximately 346 acres, 36 acres of private land, 34 unpatented mining lode claims covering approximately 550 acres, and approximately 489 acres of leased private land. In addition, the project owns 360 acres of private land for its mill site that is not contiguous with the mining claims.

Thunder Mountain Gold Inc. purchased the Project in 2007, after selling its main asset in central Idaho and donating thousands of acres at that site to conservation. The Company continues to advance the South Mountain Project, investing in excess of $20M since its purchase.

Present Condition

The South Mountain Project is an underground mine accessed by a primary horizontal adit. Existing surface rights are sufficient for all presently proposed development and operations activities. Existing infrastructure within the Project area includes six cabin-style bunkhouses (circa 1975) and a small number of other historic wooden structures, as well as a large fabric-sided equipment maintenance and storage facility situated near the entrance to the Sonneman adit. Drill core and various supplies and equipment are stored on-site in a series of locked, Connex-style storage containers located along the main access road just above the bunkhouse cabins.

Electrical power is currently supplied by portable diesel generators. A three-phase power line could be established by upgrading about 15 miles of the existing two-phase line, with the construction of an additional 4.5 miles of new line from the county road to the mine site. Line power from Idaho Power's distribution line to the mill site would require roughly one mile of new line construction and another 17 miles of existing line upgrades, along with some transformer and line upgrades near Jordan Valley, Oregon.

Potable water is available within the Project area from several existing groundwater springs. Water for milling operations is expected to be provided by an onsite well, though a pipeline could potentially be engineered to carry water to the mill from mine workings, providing water for milling operations as well as a means for dewatering the mine.

Geology & Mineralization

Rock types within the South Mountain Project area are comprised of an isolated exposure of metasedimentary and intrusive rock, surrounded by younger upper-Tertiary volcanic and sedimentary units of the Owyhee volcanic field. One large northeast trended fault runs through the South Mountain property and is informally named the Golconda Structure. This structure physiographically separates exposures of the two types of mineralization observed at the property. The current interpretation of mineralization extent on the Project shows a strike length of approximately 2,250 ft. The mineralized bodies dip approximately 50° southwest from surface (between 7,500 ft. and 7,300 ft.) to a depth of 5,900 ft. depth, or approximately 1,500 vertical ft. Mineralization thickness is variable, but the DMEA Zone massive sulfide is the most significant mineralized body with thicknesses between 10 ft. and 20 ft. Mineralization is separated into discrete high-grade bodies along strike. Mineralized continuity within those bodies is oriented down-dip and along plunge. Mineralization remains open down dip, and further exploration could result in more mineralized bodies being identified along strike or within currently undrilled parts of the Laxey Marble.

Historically, two styles of mineralization were identified and have been worked by mines on the South Mountain Project: Pb-Ag replacement vein or fissure vein deposits, and skarn-hosted, Zn-rich, polymetallic massive sulfide bodies.

The Pb-Ag veins were the first target of mining activity within the Project area. These veins proved to be amenable to early-day mining practices as the oxidized portions consisting of argentiferous lead carbonate were easily smelted. The oxidized portions of the veins are relatively shallow, on the order of 70 to 80 ft (Bowes, 1985). The unoxidized components of these veins include the sulfides pyrrhotite, arsenopyrite, sphalerite, galena, chalcopyrite, and pyrite. The sulfide minerals occur within quartz, calcite, and chlorite gangue. The Pb-Ag veins range in width from narrow stringers to 8 feet wide, and follow a predominate northeast trend with steep, southwesterly to vertical dips. The veins are open-space fillings along previous existing structures, and evidence can also be seen of localized replacement along adjacent bedding planes and fracture surfaces. The high silver values at South Mountain are present in solid solution in galena and tennantite-tetrahedrite whereas at least some of the locally high-grade gold values appear to occur in association with the early arsenopyrite.

The primary deposit being explored at South Mountain is now classified as a Carbonate Replacement Deposit ("CRD"). The CRD deposit classification commonly provides for both massive sulfide and skarn hosted mineralization. Skarns are coarse-grained metamorphic rocks composed of calcium-iron-magnesium-manganese-aluminum silicate minerals that form by replacement of carbonate-bearing rocks (in most cases) during contact or regional metamorphism and metasomatism. CRD deposits are also commonly associated with many other types of magmatic-hydrothermal deposits in mineral districts. The South Mountain CRD is potentially zoned relative to the N to NE trending faults.

Distal Pb-Ag veins and replacement bodies mined in the late 1800's may be the vertical and lateral equivalent to the main CRD system. Thus, numerous surface exposures of Pb-Ag veins at South Mountain could indicate the potential for significant Zn-Pb-Ag mineralization at depth.

History

Mineralization in the form of gold-bearing quartz veins was first discovered at South Mountain in 1868, with subsequent mining activity leading to the discovery of the oxidized silver-lead veins. The South Mountain Consolidated Mining and Smelting Company purchased the principal mines in the district, including the earliest workings of the South Mountain Project, in 1874.

The Exploration Company of California completed development of the Sonneman, Golconda, and Laxey levels of the South Mountain mine in 1929 through 1931, concentrating primarily on the Laxey ore zone. In 1940 through 1946, the International Smelting and Refining Co. (Anaconda) began metal production from the Laxey ore zone. Approximately 53,635 tons of ore were direct shipped to a smelter in Tooele, Utah during this time.

The Exploration Company of California completed exploration and development of the Sonneman, Golconda, and Laxey levels in the early 1930's, concentrating primarily on the Laxey ore zone. In 1940 and continuing through 1946, the International Smelting and Refining Co. (Anaconda) began metal production from the Laxey ore zone as part of the strategic materials effort for World War II. During this same timeframe, the Defense Minerals Exploration Administration ("DMEA") evaluated the Project for its strategic zinc potential, overseeing mining and exploration of the Project both during and for some time after the War. The Texas shaft was reactivated by the South Mountain Mines Partnership in 1950 and was worked for a period of roughly 5 years.

The Texas shaft was active from 1950 to 1955 under the South Mountain Mines ("SMM") partnership. The partnership constructed a single-stage (copper-lead circuit) flotation mill capable of handling 150 tons per day, and reportedly extracted 6,703 tons of ore. DMEA, through Anaconda, continued to evaluate the property for its strategic zinc potential during this same time frame and established the DMEA Zone ("DMEA Zone").

In 1956, the property was leased for two years to the Potash Company of America, which operated sporadically until 1968, when the 17 patented claims, which comprise the patented claim block of the present- day South Mountain Project, were purchased by W.A. Bowes, Inc.

The W.A. Bowes Company developed the property from 1977 until the early 1980's when it was purchased by an east coast investment group who formed South Mountain Mining, Inc. Following purchase of the property, W.A. Bowes remained as managing operator. The property was acquired by Thunder Mountain Resources, Inc., a wholly owned subsidiary of THMG, in September 2007 following due diligence work on the title, environmental considerations, and geology.

W.A. Bowes managed the Project from 1977 until the mid-1980's, conducting geophysical, soil and rock chip sampling and analysis programs.

After acquisition of the Project by an eastern money interest in the mid-1970s, South Mountain Mining ("SMM") was incorporated and proceeded to conduct expansive exploration in the form of tunneling and underground and surface drilling. SMM personnel have verbalized to THMG personnel that approximately $6 million was spent at the Property by them during this period, culminating in preparation of an internal feasibility study.

SMM collected 60 channel samples in the Sonneman drift to delineate mineralization in the DMEA and Texas zones. Orientations for these samples are either along the length of the drift, which is approximately along strike of the deposit, or across the drift. The channel sampling successfully defined high grade mineralization for the Project.

Historic drilling on the property began in the 1960's when Potash Corporation drilled 10 core holes of unknown size totaling 1,293 ft and 24 longholes totaling 2,078 ft. All drilling was conducted across the length of the Laxey level and successfully tested the vertical continuity of mineralization. In 1971, Austral Oil drilled 8 core holes totaling 7,551 ft north of the Project. The Austral hole intervals were logged for geology but were not assayed for metal content. In the period from 1975 to 1986, SMM drilled a total of 161 holes. Of these holes, 117 were longholes (blastholes) totaling 4,817 ft. Thirty-nine were core holes totaling 5,467 ft. The remaining 5 holes were shallow air track holes, which were not assayed, totaling 486 ft. The drilling by SMM largely defined the extent of mineralization for the Project prior to drilling operations by, or on behalf THGM.

Work Completed and Exploration Plans

Exploration (and development) activities conducted at South Mountain since 2008 include:

Adjoining property evaluation and acquisition

Title work for the patented claims and private land parcels

Surveying the claim boundaries,

Rehabilitation of the Laxey and Sonneman drifts, most to a production level (12 ft by 12 ft),

As-built survey of the Laxey and Sonneman drifts,

Channel sampling of the Sonneman drift at the intersections of massive sulfide mineralization,

Geologic mapping and geochemical sampling specific to an intrusive breccia target, and

A ground magnetics survey as well as compiling and reprocessing public domain geophysical surveys, and

A pulse electromagnetic ("PEM") survey completed in September 2022

A broad district-wide Magneto telluric geophysical survey in 2025 that is still under evaluation, along with district-wide reconnaissance and geochemical studies.

An additional 399 lode claims were staked at South Mountain in 2025, bringing the total to 410 lode claims. Additionally, the Company purchased 113 acres of contiguous private mineral land that the Company previously leased.

The procedures, parameters, and general results of each of the exploration efforts listed above are summarized below and detailed descriptions can be found in Exhibit 96.1, the Initial Assessment Technical Report Summary for the South Mountain Project, Owyhee County, Idaho U.S.A, with an effective date of December 31, 2023.

Channel Sampling in the Sonneman Drift:

THMG conducted further mapping and collected several channel samples in Muck Bay 3 in the Sonneman Drift in an effort to delineate mineralization in this zone of the Sonneman level. Chip samples along a channel were taken with rock picks and/or hammer and chisel. Care was taken to make sure that the amount along the run was distributed evenly. Samples were carefully detailed and shipped to ALS Chemex in Reno, Nevada. The results from the sampling confirmed further high grade mineralization at the Project in this zone.

Geochemical Sampling:

In 2025, the Company embarked on a district-wide geology reconnaissance, structural mapping and geochemical sampling program. Some historic drill roads were re-established and sampled on 5 foot and 10 foot intervals. All geochemical samples were analyzed with X-ray fluorescence prior to submitting lab analysis. The new data, along with historical data is being combined into a global model at the Project.

Historic Geochemical Sampling:

Approximately three miles of access roads and drill sites were constructed in 2010 during exploration of the gold breccia. A campaign of road cut sampling was undertaken on the new roads as they were completed. Three sets of samples were obtained along the cut bank of the road. Channel samples were taken on 25-foot, 50-foot or 100-foot intervals, depended upon the nature of the material cut by the road with the shorter spaced intervals being taken in areas of bedrock. A majority of the samples contained anomalous gold values and in addition to confirming the three anomalies identified by soils sampling.

Rock chip samples collected by THMG staff from the intrusive breccia and the surrounding rocks. Additional rock chip samples were collected by Kinross geologists in 2009 during an evaluation of the property. Kinross collected rock chip samples from the breccia at South Mountain that produced gold values closely matching the rock chip geochemical values collected by THMG staff. The gold values increase in rock chip samples collected from along the contact of the intrusive breccias.

A soil sample program was conducted in the area of the intrusive breccia on South Mountain by THMG staff. Soil samples collected from a 2008 orientation sample grid over the breccia zone. During the 2009 field season, an expanded soil grid was completed over the breccia zone.

Also in 2010, Newmont Mining Corp. submitted two bulk samples for gold characterization and modal mineralogy. The samples comprised approximately 1.5 kilograms of -10-mesh rejects from ALS Chemex.

Geophysics:

In 2010, J.L. Wright Geophysics compiled several geophysical datasets:

Airborne magnetic data ("AMAG");

Airborne radiometric data ("ARAD"); and

The gravity data ("GRAV").

The gravity data indicates the property to be located at an intersection of two large scale structural features. Density variations, responsible for the gravity anomalies, are inferred to be related to large scale basement rock changes. Results from the survey show complex magnetic patterns produced by both lithologic and alteration features.

In July 2013, a ground magnetic survey was completed over a portion of the South Mountain property by MaGee Geophysical Services LLC. The objective was to delineate structures and lithologies proximal to known gold and base metal mineralization.

In September 2022, Crone Geophysics based in Toronto, Canada completed a pulse electromagnetic ("PEM") survey covering a portion of the Project area. The survey is initially centered on the South Mountain Mine, then follows the marble unit to the north with the objective of delineating massive sulfides. The 2022 geophysics survey suggests the presence of additional exploration targets beyond the extent of currently defined mineralization.

In August 2025, Durango Geophysics, and John Reynolds, embarked on a broad Magnetotelluric geophysical survey. The results of this effort are still under evaluation.

Drilling:

In 2019, 2020, and 2021, SMMI completed a total of fifty-two (52) NQ diameter core drillholes totaling 16,382 ft. as well as two HQ diameter core drillholes totaling 3,541 ft. The drilling completed in 2021 was from surface and targeted the down-dip extension of the DMEA. The 2021 drilling intersected the mineralization approximate to the true thickness of the deposit. The 2020 drillholes were surveyed down-hole using a GyroMaster non-magnetic multi-shot tool. Between 2008 and 2018, THMG drilled twenty-seven (27) holes for a total of 16,600 ft. Twenty of the holes are diamond core holes, and the remaining seven are RC.

THMG completed two core holes in 2008, TX-1 and DMEA2. TX-1 was drilled from surface, oriented south-southwest and inclined 60° targeting Texas mineralization. DMEA2 was drilled from surface, and oriented vertically. The drillhole was surveyed down-the-hole every 10 ft using a Deviflex multishot survey tool. The drillhole intersected DMEA zone mineralization at depth.

In 2010, THMG completed seven (7) RC drillholes with the prefix LO. The drillholes were vertically oriented and not surveyed down-the-hole. LO-01 through LO-05 targeted the intrusive breccia defined by geologic mapping and rock chip samples across a strike length of 4,440 ft. These drillholes were assayed for gold only and intersected several low-grade intercepts (Table 7-7).

In 2013, the Company's drilling program consisted of twelve (12) drillholes targeting three mineralization zones from surface and surveyed down-the-hole every 10 ft using a Deviflex multishot survey tool. This drilling orientation is not preferred for intersecting mineralization across the true thickness of the deposit; however, three (3) of the four (4) drillholes did intersect massive sulfide mineralization associated with the Texas zone. The 2013 drilling also included six underground core drillholes with the prefix DM2UC13. The program was successful in defining the geometry and confirming the grades of the DMEA massive sulfide zone.

For more information on the drilling results, see the Initial Assessment Technical Report Summary for the South Mountain Project, Owyhee County, Idaho U.S.A, attached hereto as Exhibit 96.1.

Mineral Resource Estimate

The Company completed an updated mineral resource estimate (the "MRE") with an effective date of December 31, 2023, to meet the requirements of Subpart 1300 of Regulation S-K, which incorporated results from the surface diamond drilling program conducted in 2021 at the South Mountain Project. The MRE includes an increased resource for the Project while maintaining the high-grade mineralization. The MRE was prepared in accordance with Subpart 1300 of Regulation S-K by Hard Rock Consulting, LLC, based in Aurora, Colorado, U.S.A. For more information, see Exhibit 96.1, the Initial Assessment Technical Report Summary on the South Mountain Project, Owyhee County, Idaho U.S.A., prepared for the Company by Hard Rock Consulting, LLC ("HRC"), the Qualified Person ("QP"). The South Mountain Project is without known reserves, and the proposed programs are exploratory in nature.

Highlights of Mineral Resource

Measured & Indicated ("M&I"): 223,000 tons grading 9.02% Zinc ("Zn"), 4.27 ounces per ton ("opt") Silver ("Ag"), 0.059 opt Gold ("Au"), 0.64% Copper ("Cu"), and 0.94% Lead ("Pb").

Inferred: 959,000 tons grading 7.56% Zn (14% increase in Zn lbs.), 5.67 opt Ag (14.10% increase in Ag ounces), 0.037 opt Au (3.3% increase in Au ounces), 0.80% Cu (14.5% increase in Cu lbs.), and 1.06% Pb (25.4% increase in Pb lbs.).

The DMEA Zone in the model was extended an additional 250 feet down dip and remains open.

This latest round of drilling completed during the late fall of 2021 proves the continuation of the down plunge extension of the DMEA Zone at depth. This zone remains open in both directions. All of the drill results have now been in incorporated into the MRE for the South Mountain deposit. The increase in Measured and Indicated tons are the result of updated metal prices and mining costs. Surface drilling completed in 2021 accounts for approximately 8% of the increase in Inferred tons, while the remaining 7% increase is due to updated metal prices and mining costs.

Table 1 below provides the Mineral Resource Statement for the Project in U.S. units with details of the modeling methodology and cut-off grades applied to the mineral resource.

Table 1. South Mountain Mineral Resource Statement as of December 31, 2023

Massive Sulfide Type Metallurgical Domain

21

Total

1. The undiluted in-situ mineral resources are reported at an underground mining Net Smelter Return ("NSR") cut-off of 97.50 $US/Short Ton. The NSR calculation is based on the assumptions stated in the following footnotes 2 - 5.

2. Metal prices are based on the 36-month moving average as of September 29, 2023, and are $1,800/oz for Au, $23.50/oz for Ag, $1.00/lb. for Pb, $1.35/lb. for Zn, and $4.00/lb. for Cu.

3. An assumed mining cost of $65/short ton, process costs of $25/short ton, and general and administrative costs of $7.50/short ton

4. Massive Sulfide type metallurgical recoveries and payables are 52.25% for Au, 71.25% for Ag, 71.40% for Zn, 66.50% for Pb, and 49.00% for Cu and a total smelter cost of $33.29.

5. Skarn type metallurgical recoveries and payables are 71.25% for Au, 80.75% for Ag, 51.00% for Zn, 47.50% for Pb, and 87.70% for Cu, and a smelter cost of $7.24.

6. Rounding may result in apparent differences when summing tons, grade and contained metal content. Tonnage and grade are in U.S. Customary units. Prices are in $US.

Qualified Person Statement for the Mineral Resource Estimate

Hard Rock Consulting, LLC is responsible for the South Mountain Project MRE, with an effective date of December 31, 2023. HRC is a Qualified Person as defined by S-K 1300 and is independent of Thunder Mountain Gold, Inc. and South Mountain Mines, Inc. HRC estimated the mineral resources based on drill-hole and channel sample data constrained by geologic boundaries using an Ordinary Krig algorithm. The Geologic Model and Mineral Resource Estimate were completed using Leapfrog Geo® Software version 2023.1.1. HRC based the MRE on other assumptions that can be found in the footnotes to Table 1, above.

Permits

The Project is largely on, and surrounded by private land, and as such, the permitting and environmental aspects of the Project are expected to be straightforward. Permits are currently in place for underground and surface exploration and development activities as follows:

In 2007, the BLM contracted with North Wind Environmental (North Wind) to design a reclamation program for the estimated 16-17,000 tons of tailings situated solely on BLM land below the Sonneman Mine Portal and waste rock dump area. North Wind completed the outlined reclamation work in October 2007 by providing diversion ditches for a small side-drainage to Williams Creek, shaping and capping with both synthetic HDPE plastic and soil and fencing the area to exclude livestock access. The reclaimed area was also seeded then covered with straw mat material to minimize erosion.

As part of their due diligence in 2007, THMG conducted water sampling at the mine portals and various other locations along Williams Creek. They also contracted with Enviroscientists, Inc. of Reno, Nevada, to conduct an environmental data review and site assessment. Based on the completed state and federal site work and environmental evaluations, THMG determined that environmental liabilities associated with the Project are minimal, and therefore an acceptable risk, given the history of state and federal and environmental evaluations and remediations in and around the site. There are no current applicable federal or state environmental orders regarding the site.

THMG also completed water quality sampling programs on a quarterly basis from 2012 through 2014, during that phase of exploration and pre-development work. Several sample stations were established along the stream from the area below the Sonneman waste rock dump and historic tailings repository. This baseline sampling has continued through and into the current exploration program through the fourth quarter of 2020. No significant variations in quality, trends or concerns were noted in the sampling.

In 2020, THMG and their independent consultant, WEC, updated the existing site-wide Storm Water Pollution Prevention Plan (SWPPP) under guidance of the EPA NPDES Stormwater Discharges from Industrial Activities-EPA's 2015 Multi-Sector General Permit (MSGP).

The Idaho DEQ manages the regulatory compliance of this program as of beginning in July of 2021.

The current site conditions related to underground water and the mine portal are as follows:

1. As mentioned above, Williams Creek has been placed in a 660 feet of 48-inch galvanized culvert through the Sonneman waste rock dump, starting above the mine workings, and continuing below the workings, in order to protect Williams Creek, and to ensure compliance with the National Pollutant Discharge Elimination System (NPDES/IPDES) Stormwater Permit.

2. There is no direct or open surface channel that routes water from underground tunnels or drifts, out of the mine and into Williams Creek. All water underground is considered meteoric and finds its way down through and below mine infrastructure. There is no way in which to determine if or how this water supplements the flow in Williams Creek.

3. The surface water sampling baseline data that has been collected for about 14 years shows no upstream or downstream influence from constituent analysis on Williams Creek.

4. Even though Williams Creek is routed through a 48-inch culvert for 660 feet to protect the water, it still crosses over and through the host rock and mineralized zones that are part of the system of mineralization.

If mining operations in the future require dewatering in the mining areas, then an IPDES Permit would be required for point source discharges from the mining operation to "waters of the United States." Likely point discharges would include treated mine drainage, treated net precipitation from the tailings storage facility, and any other discernible or discrete point source associated with mining and processing at the site. In addition, the project would be subject to performance standards for new sources for its respective industrial source category. The Project would have to demonstrate that it is applying the best available control technology to meet applicable water quality standards. The permit application must be submitted at least 180 days prior to the approved discharge.

Scoping has been conducted by management, and several independent contractors have been invited to submit proposals for air quality baseline monitoring and permitting. Permits to construct and then later to operate are expected to be required for both the mine and mill and would be submitted with information developed from further mine and mill planning to include engineering studies and equipment lists.

In November 2019, South Mountain Mines, Inc./Owyhee Gold Trust filed an application with the Owyhee County Planning and Zoning Commission requesting a second four-year time extension for previously approved conditional use permit 213-13. That permit was originally issued in 2013 to Owyhee Gold Trust LLC, granting approval to establish an industrial milling operation on approximately 360 acres of land located in an agricultural zone. The first four-year time extension was applied for and granted in 2015. The subject parcels are located in the NE¼ of Section 23, the SW¼ of the NE¼, and the SE¼ of Section 14 Township 7 South, Range 5 West, Boise Meridian, Owyhee County, Idaho. Following a duly noticed hearing on December 11, 2019, the Commission granted the time extension of four (4) years, subject to the special conditions set forth in the original approved conditional use permit.

In 2023, the Commission granted the Company a one (1) year extension with the existing CUPs, with the understanding that the Company will update and submit a new application that is more specific to the current exploration activities. SMMI keeps the County up to date and informed with annual presentations to the Owyhee County Commissioners.

In 2025, the Company initiated discussions with Owyhee County Planning and Zoning to update and submit new information for new CUPs at both the mine site and mill site. Further technical information is being gathered to submittal of the new CUP applications.

Internal Controls Over Exploration and Mineral Resource Estimations

Exploration drilling programs in 2019, 2020, and 2021 are performed using industry-standard quality control methods for drilling, logging, sampling, and analytical procedures. The laboratory used by THGM for sample preparation and analyses is ALS USA Inc., 4977 Energy Way, Reno, NV 89502. ALS meets all requirements of International Standards ISO/IEC 17025:2017 and ISO 9001:2015. All ALS geochemical hub laboratories are accredited to ISO/IEC 17025:2017 for specific analytical procedures. Gold was analyzed using a 30g charge and fire assay methods with an atomic absorption finish. Ag, Cu, Pb Zn, as well as 29 additional elements were then analyzed were analyzed using a 0.25g sample by four acid digestion with an induced plasma couple mass spectroscopy finish. Gold results exceeding 10ppm and silver results exceeding 100ppm were reanalyzed using a 30g charge and fire assay methods with a gravimetric finish. Zinc, Copper and Pb results exceeding 10,000ppm, were reanalyzed using 0.4g sample with four-acid digestion.

The drilling competed by THMG in 2019, 2020, and 2021 included three types of QA/QC samples including blanks, standards, and duplicates into the sampling program. The combined THMG drilling program totaled 1,537 sampled intervals and 209 recorded QA/QC samples representing approximately 14% of the sampled intervals. All standards are commercially certified and have been prepared in advance by accredited labs. HRC reviewed blank, standard, and duplicates and found the results from QA/QC samples to be acceptable.

Drill core, chip trays, and pulp rejects are stored in locked, Connex-style shipping containers located at the Project site. Coarse rejects are temporarily stored in a secure rental storage unit in Elko, Nevada, and are periodically hauled to the mill site for long term storage in the gated, covered storage area. Samples are continuously monitored by SMMI personnel from the time of collection through delivery to the lab. THMG employs standard chain of custody procedures, including formal COC documentation, during all phases of sample transport.

The sampling methods meet industry standard practices and are adequate for mineral resource estimation. Sampling was conducted by appropriately qualified personnel under direct supervision of appropriately qualified geologists. Sample collection procedures used meet industry best practices. Sample preparation procedures meet industry best practices. QA/QC results produce acceptable results. Security procedures are consistent with industry standards. The databases are managed in a secure area using modern, commonly used software by trained staff. The staff are experienced in the nuances of narrow vein mining and treat the model with their experience in mind.

Drillhole logs are completed using Microsoft Excel and are only accessible by mine technical staff and timestamped at the last time of change. Geologic interpretation and solid modeling, and mineral resource estimation are accomplished using Leapfrog. Hard copies of the most critical log data are printed from the "log form" tab. Electronic copies are kept by THMG and both electronic and hard copies are in the possession of Thunder Mountain Gold. This redundancy is to ensure against any data loss.

Risks and uncertainties exist in the quantification of the spatial distribution on mineralization. These risks are inherent in the estimation of mineral resources. Samples themselves have uncertainty related to sampling collection errors and the homogeneity of the deposit. Wider spaced drilling has more uncertainty than closely spaced drilling. High grade outlier samples will tend to overestimate the metal content of the mineral deposit. These underlying factors and risks were considered in the final conclusion of the mineral resource estimate.

Additional Project Highlights

Durango Geophysics, etc.

On September 17, 2024, the Company completed remodeling its geological data and historical reports for the South Mountain Project utilizing acquired induced polarization (IP) data, airborne magnetic geophysical survey data, and copper-in-soil geochemical survey (Geochem) results. Based on this analysis, the Company staked an additional 13 unpatented mining claims, covering approximately 260 acres of Bureau of Land Management (BLM) land.

On December 13, 2023, the Company completed a land purchase of an additional 56 acres of strategic land at the Company`s South Mountain Project. The land is a combination of both patented and private land, with full mineral rights, and was previously leased by the Company in prior years. The parcel is contiguous with the South Mountain patented claims and is important to the future development of the Texas Zone. This land acquisition covers a gap in the main mine area and eliminates any outside ownership within the main mine area.

On September 5, 2022, Crone Geophysics based in Toronto, Canada initiated a time domain pulse electromagnetic (PEM) survey over a portion of the South Mountain Mines. The objective of the survey is to delineate massive sulfide mineralization within a marble unit bounded by Paleozoic schists. Historic mining on the area was conducted on massive sulfide mineralization associated hosted by the Laxey Marble within the survey area. Bowes (1985) describes the sulfide bodies as pipe-like dipping to the southwest at 40-50° and raking 50°. The survey was completed on November 7, 2022. In addition to the PEM survey, property scale topography, geology and ground magnetics will be included to provide supporting data for the interpretation. The digital products include raw data, intermediate processed products, and final products in several data formats.

In May of 2021, the Company and its project team completed an updated Mineral Resource Estimate ("MRE"), incorporating results from Phase 1 and 2 underground diamond drilling programs at the South Mountain Project. The updated MRE includes a substantially increased resource for the Project while maintaining the high-grade nature of the mineralization.

Later in 2021, the Company embarked on a phase 3 program at South Mountain with the objective to significantly expand the scale of the current MRE at South Mountain (See Summary of the MRE above), testing and establishing the down depth extent of mineralization on the DMEA Zone. The DMEA Zone is the largest known body of mineralization on the Property, containing the majority of tonnage in the current MRE, and the mineralized zone remains open at depth.

Based on the last two phases of underground drilling, the surface core drilling, and all the historical exploration data available, the Company believes there is the potential to expand the down-plunge extensions of the mineral resource with this new phase of surface drilling at the Property.

The Company's plan of operation for the next twelve months, subject to business conditions, will be to continue to advance the South Mountain Project, including continued baseline environmental and engineering work necessary to further our Preliminary Economic Analysis or Initial Analysis.

South Mountain Project - MFD Option Agreement

On January 27, 2025, the Company announced a strategic partnership with Swiss-based MFD Investment Holdings SA ("MFD"). The letter agreement signed outlines that MFD will provide additional funding, contributing $1,000,000 in project-related expenditures as well as providing technical support for project development. This partnership adds additional financial strength in advancing South Mountain's technical and economic studies. The letter agreement is in the form of an option, whereby THMG grants an option to MFD to earn an interest in its South Mountain Project pursuant to which MFD shall have the right, but not the obligation, to complete certain requirements in return for the acquisition of a 10% interest in the Project.

Note to United States investors concerning estimates of measured, indicated and inferred resources.

Information concerning our mining properties has been prepared in accordance with the requirements of Subpart 1300 of Regulation S-K, which first became applicable to us for the fiscal year ended December 31, 2021. These requirements differ significantly from the previously applicable disclosure requirements of SEC Industry Guide 7. Among other differences, Subpart 1300 of Regulation S-K requires us to disclose our mineral resources, in addition to our mineral reserves, as of the end of our most recently completed fiscal year both in the aggregate and for each of our individually material mining properties. You are cautioned that mineral resources do not have demonstrated economic value. Mineral resources are subject to further exploration and development, are subject to additional risks, and no assurance can be given that they will eventually convert to future reserves. Inferred Resources, in particular, have a great amount of uncertainty as to their existence and their economic and legal feasibility. Investors are cautioned not to assume that any part or all of the Inferred Resource exists or is economically or legally mineable. See Item 1A, Risk Factors.

Book Value of the South Mountain Project

The book value of the property and associated plant and equipment can be found in Note 4 to our Consolidated Financial Statements ITEM 8, Part II of this Annual Report.

Comparison of the South Mountain Project Mineral Resources with Preceding Fiscal Years

Because the Company's Technical Report Summary was previously prepared in accordance with the requirements of Canadian securities laws, including Canadian National Instrument 43-101 ("NI 43-101"), we assume the Company has no prior Subpart 1300 Mineral Resources in which to make a comparison.

Figure 2 - Trout Creek Property

Trout Creek Project, Lander County, Nevada

The Trout Creek Project is a highly prospective gold Exploration Stage Property operated by the Company and located along the western flank of the Shoshone Mountain Range in the Reese River Valley in Lander County, Nevada. The Project is located approximately 155 air miles northeast of Reno, Nevada, or approximately 20 miles south of Battle Mountain, Nevada, in Sections 10, 11, 14, 16, 21, 22, 27; T.29N.; R.44E. Mount Diablo Baseline & Meridian, Lander County, Nevada. Latitude: 40 23' 36" North, Longitude: 117 00' 58" West. The property is generally accessible year-round by traveling south from Battle Mountain Nevada on state highway 305, which is paved.

Property Ownership and Acreage

The Trout Creek Project consists of 26 (approximately 533 acres) unpatented lode mining claims owned by Thunder Mountain Resources, Inc. ("TMRI"), our wholly-owned subsidiary. The Company must pay annual maintenance payments to the Bureau of Land Management ("BLM") to maintain its rights to the property. BLM annual maintenance fees increased to $200.00 per claim, which became effective for the 2024 assessment year.

Geology & Mineralization

The Trout Creek Project target is anchored by a regional gravity anomaly on a well-defined northwest-southeast trending structural components, causing a break in the alluvial fill thickness and underlying bedrock. Previous geophysical work in the 1980s revealed an airborne magnetic anomaly associated with the same structure, and this was further verified and outlined in 2008 by Company personnel, with consultation from Jim Wright - Wright Geophysics using a ground magnetometer. The target is covered by alluvial fan deposits of generally unknown thickness, shed from the adjacent Shoshone Range, a fault block mountain range composed of Paleozoic sediments of both upper and lower plate rocks of the Roberts Mountains thrust.

Wright Geophysics also conducted a ground gravity survey and CSMAT over the pediment target area and this provided insight into the gravel-bedrock contact as well as defining the favorable structural setting within the buried bedrock. An untested drill target was identified under the gravel pediment along these structures, and the geophysics showed that the bedrock was within 500 feet of the surface, which is reasonable depth for exploration drilling and potential mining if a significant mineralization is encountered.

Present Condition, Work Completed and Exploration Plans

Other than the geophysical data described above, the Company has not performed any significant work at the Trout Creek Project since 2011. However, the Company may conduct further exploration on the Trout Creek Property in 2026. The Company continues to concentrate on advancing the South Mountain Project. There are no significant workings on the property, and the property is without known resources or reserves.

Permits and Facilities

There are no permits associated with this property, and there are no processing plants or other available facilities located on the property. There are currently no environmental permits required for exploration work on the property. In the future, a plan of operations may be required by the Bureau of Land Management to conduct exploration and sampling at the property.

Competition

We are an Exploration Stage Issuer. We compete with other mineral resource exploration and development companies for financing and for the acquisition of new mineral properties. Many of the mineral resource exploration and development companies with whom we compete have greater financial and technical resources than us. Accordingly, these competitors may be able to spend greater amounts on acquisitions of mineral properties of merit, on exploration of their mineral properties and on development of their mineral properties. In addition, they may be able to afford greater geological expertise in the targeting and exploration of mineral properties. This competition could result in competitors having mineral properties of greater quality and interest to prospective investors who may finance additional exploration and development. This competition could adversely impact on our ability to finance further exploration and to achieve the financing necessary for us to develop our mineral properties.

The following Management's Discussion and Analysis of Financial Condition and Results of Operation ("MD&A") is intended to help the reader understand our financial condition. MD&A is provided as a supplement to, and should be read in conjunction with, our financial statements and the accompanying integral notes ("Notes") thereto. The following statements may be forward-looking in nature and actual results may differ materially.

Plan of Operations:

The Company, including its subsidiaries, owns mining rights, mining claims, and properties in the mining areas of Nevada and Idaho, which includes its South Mountain Property in Idaho, and its Trout Creek Property in Nevada.

The Company owns 100% of the outstanding stock of Thunder Mountain Resources, Inc., a Nevada Corporation. Thunder Mountain Resources, Inc. owns 100% of the outstanding stock of South Mountain Mines, Inc. (SMMI), an Idaho Corporation. Thunder Mountain Resources, Inc. completed the direct purchase of 100% ownership of South Mountain Mines, Inc. on September 27, 2007, which consisted of 17 patented mining claims (approximately 327 acres) located in Owyhee County in southwestern Idaho. After the purchase, Thunder Mountain Resources staked 34 unpatented mining lode claims covering approximately 550 acres, and approximately 489 acres of leased private land. In addition, the project owns 360 acres of private land for its mill site that is not contiguous with the mining claims.

The Company's plan of operation for the next twelve months, subject to business conditions, will be to continue to advance the South Mountain Project, including continued baseline environmental and engineering work necessary to complete a Preliminary Economic Analysis or Initial Analysis. The Company plans to continue to explore options to advance the South Mountain Project and acquire additional properties through partnerships, joint ventures, option agreements, and strategic relationships.

Results of Operations:

For the year ended December 31, 2025, the Company reported a net loss of $2,829,759 ($0.03 per share), compared to a net loss of $631,111 ($0.01 per share) in 2024. The increase in net loss for the year ended December 31, 2025, was primarily attributable to higher operating expenses, including increased exploration activity, professional fees, and stock-based compensation associated with financing and corporate development efforts during the year.

As an exploration-stage company, Thunder Mountain Gold, Inc. does not generate revenue from operations. The Company is focused on mineral exploration and development activities and does not have producing mines or commercial production at this time. Accordingly, certain disclosure requirements related to changes in sales, revenue, and cost of goods sold do not apply.

Fourth Quarter comparisons

Operating expenses for the fourth quarter ended December 31, 2025, totaled $903,862 representing an increase of $710,941, or approximately 369%, compared to $192,921 for the same period in 2024. The increase in fourth-quarter operating expenses was primarily driven by higher exploration and management and administrative costs incurred during the period.

Exploration expenses for the fourth quarter ended December 31, 2025, were $274,888, an increase of $209,408 compared to $65,480 for the corresponding period in 2024. The rise was driven by strategic exploration initiatives undertaken to advance the Company's mineral interests.

Legal and accounting expenses for the fourth quarter ended December 31, 2025, totaled $103,484, compared to $41,027 for the same period in 2024, representing an increase of $62,457. The increase primarily reflects professional service fees incurred in connection with outsourced financial consulting services, as well as legal fees related to water rights and claim fees being negotiated on behalf of SMMI.

Management and administrative expenses for the three months ended December 31, 2025, increased to $525,490, compared to $86,414 for the same period in 2024, an increase of $439,076. This increase was largely due to non-cash stock-based compensation expenses related to option grants issued to a consultant for services previously rendered and accrued Board compensation.

Year-end comparisons December 31, 2025 vs 2024

Operating expenses for the year ended December 31, 2025, totaled $2,826,781 representing an increase of $2,241,168 or approximately 383%, compared to operating expenses of $585,613 for the year ended December 31, 2024. The increase in operating expenses was primarily attributable to elevated exploration activity, increased professional fees, and stock-based compensation recognized during 2025.

Exploration expenses for the year ended December 31, 2025 were $911,511, an increase of $763,507 compared to $148,004 for the corresponding period in 2024. The rise was driven by strategic exploration initiatives undertaken to advance the Company's mineral interests.

Legal and accounting expenses increased to $262,203 for the year ended December 31, 2025, compared to $112,623 in 2024, representing an increase of $149,580, or approximately 133%. The increase was primarily driven by costs associated with regulatory filings, and professional services required to support the Company's public reporting and corporate activities.

Management and administrative expenses increased to $1,653,067 for the year ended December 31, 2025, compared to $324,986 in 2024, an increase of $1,328,081, or approximately 409%. This increase was largely due to non-cash stock-based compensation expenses related to option grants issued to consultants, executive officers and members of the Board of Directors.

Liquidity and Capital Resources:

The consolidated financial statements accompanying this report have been prepared assuming the Company will continue as a going concern. Such an assumption contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. As shown in the consolidated financial statements for the year ended December 31, 2025, we have cash reserves sufficient to cover normal operating expenditures for the following 12 months.

Long-term strategies involve financing through stock or debt sales and eventual profitability from mining operations. Capital raising efforts are challenging given the current capital market conditions and the broader economic climate in the United States. Company management is actively seeking additional funds through various means, including public offerings, private placements, mergers, option agreements, and external debt, to ensure the Company's viability.

On November 28, 2024, the Board of Directors authorized a private placement financing of up to $700,000, offering equity units at $0.05 per unit. Each unit consisted of one share of common stock and one common stock purchase warrant, with each warrant exercisable for one additional share at $0.10 per share for 36 months from issuance.

On December 16, 2024, the Company closed the private placement, issuing 12,400,000 shares of common stock and an equal number of common stock purchase warrants, generating gross proceeds of approximately $620,000, including $20,000 in non-cash consideration for vendor services.

On April 15, 2025, the Company Board approved a private placement financing of 10,000,000 units at a price of $0.12 per unit for total proceeds to the company of $1,200,000. Each unit includes one share of common stock and one-half warrant to purchase one share of common stock, exercisable for 2 years from the close of the offering at an exercise price of $0.18 per share. On May 25, 2025, the Company closed the private placement of 10,000,000 units for aggregate proceeds of $1,200,000. No placement agent fees were paid during the offering.

On October 1, 2025, the Company Board approved a private placement financing of 10,000,000 units at a price of $0.25 per unit for total proceeds to the Company of $2,500,000. Each unit includes one share of common stock and one-half warrant to purchase one share of common stock, exercisable for 2 years from the close of the offering at an exercise price of $0.40. On October 24, 2025, the Company completed a non-brokered private placement financing pursuant to the Board's approval on October 1, 2025.

Our plans for the long-term viability include financing our future operations through sales of our common stock and/or debt and the eventual profitable exploitation of our mining properties. There can be no assurance that such activities will be successful.

At December 31, 2025, we had current assets of $2,698,225. Our future liquidity and capital requirements will depend on many factors, including timing, cost and progress of our exploration efforts, our evaluation of, and decisions with respect to, our strategic alternatives, and costs associated with the regulatory approvals. Our short-term liquidity needs and capital requirements consist primarily of exploration expenses, lease payments, salaries and administrative expenses and required principal and interest payments under the seller-financed promissory note issued in December 2025; our longer-term liquidity needs include construction and equipment costs if we are able to successfully progress our project to operations. If we do not have enough cash to complete our exploration programs, we intend to seek to raise additional funds from public offerings, sale of liquid stock or loans or to adjust our business plans accordingly.

On March 19, 2026, the Company had a cash and cash equivalent balance of $2,041,803 in our bank accounts, which does not include consideration for option payments mentioned below.

Management's goal is to manage expenses to not exceed the on-hand cash resources of the Company.

The Company will also consider other sources of funding, including potential mergers or lease option to purchase, the sale of all or part of the Company`s assets, and/or additional farm-out of its other exploration property.

For the year ended December 31, 2025, the Company discloses net cash used by operating activities of $1,609,019, compared to net cash used by operating activities of $539,287 in 2024. The increase in cash used by operating activities during 2025 was primarily attributable to higher operating expenditures associated with expanded exploration activity, and professional fees. During the year ended December 31, 2025, net cash used in investing activities was $55,136, which primarily reflects cash expenditures associated with the acquisition of private land completed on December 9, 2025. The total purchase price of the land was approximately $260,136; however, approximately $205,000 of the purchase price was financed through the issuance of a seller-financed promissory note. Accordingly, the majority of the land acquisition was a non-cash investing and financing transaction. This compares to net cash provided by investing activities of $384,981 in 2024, which was generated from the sale of BeMetals common stock. For the year ended December 31, 2025, the Company reported net cash provided by financing activities of $3,775,000, primarily reflecting proceeds from private placement financings resulting in the issuance of common stock and warrants totaling $3,650,000, as well as $130,000 received from the collection of a common stock subscription receivable. These cash inflows were partially offset by $5,000 in distributions made to a noncontrolling interest holder (see Note 3).

The Company realized a net cash increase of $2,110,845 for the year ended December 31, 2025, compared to a net cash increase of $310,694 for the corresponding period in 2024.

Contractual Obligations

Ascent CFO Solutions, LLC:

On April 10, 2025, the Company entered into a services agreement with Ascent CFO Solutions, LLC to provide outsourced financial consulting services.

The Company holds leases pertaining to land parcels adjacent to its South Mountain patented and unpatented mining claims. The details of these leases are as follows:

Former Acree Lease:

On June 20, 2008, the Company entered into a lease agreement with Ronald Acree for a six-year term covering 113 acres at a lease rate of $20 per acre. The lease agreement included options to extend at increasing rental rates. Effective June 2025, upon entering the 17th year of the lease term, the lease was extended an additional 10 years. On December 9, 2025, the Company completed the acquisition of the 113-acre property previously subject to the Acree Lease pursuant to a purchase and sale agreement (see Note 4 & Note 6). As a result of the acquisition, the lease agreement was terminated, and no further lease payments are required.

Lowry Lease:

On October 24, 2008, the Company executed a lease agreement with William and Nita Lowry for a duration of 6 years, encompassing 376 acres at a rate of $20 per acre. The lease incorporated an option to extend for an additional 10 years at a revised rate of $30 per acre. Following the passing of the original lessors, the lease was inherited by Michael Lowry, their son. Commencing October 24, 2025, the Company executed an extension to the lease agreement with Michael Lowry for an additional 21 years, through October 24, 2046. Under the amended lease agreement, the annual rental payments for the first seven years increased to $40 per acre. The rental rate increases to $50 per acre for the second seven-year period and increases to $60 per acre for the final seven-year period.

Looten Lease:

On June 2, 2025, the Company executed a lease agreement with Kevin and Jo Looten for an initial term of 7 years, encompassing 18 acres at a rate of $30 per acre. The lease incorporates an option to extend for an additional 10 years at a revised rate of $40 per acre.

Lequerica & Sons Lease:

On August 22, 2025, the Company executed a lease agreement with Lequerica & Sons, Inc. for an initial term of 7 years, encompassing 432 acres at a rate of $30 per acre. The lease incorporates an option to extend for an additional 7 years at a revised rate of $40 per acre. The lease agreement also contains a right of first refusal in favor of the Company with respect to the underlying property, exercisable upon a proposed sale by the lessor.

OGT, LLC

SMMI is the sole manager of the South Mountain Project in its entirety through a separate Mining Lease with Option to Purchase ("Lease Option") with the Company's majority-owned subsidiary OGT. SMMI has an option to purchase the South Mountain mineral interest for a capped $5 million less net returns royalties paid through the date of exercise. The Lease Option expires in November 2026. Under the Lease Option, SMMI paid annual $5,000 net returns royalty payments to OGT through November 2025. The final $5,000 payment was made in November 2025, and no further payments are due under this arrangement.

The leases and net royalties' payment are summarized in the following table.

(1) The amounts presented above reflect the current annual rental rates in effect as of December 31, 2025, and do not reflect scheduled future rental rate increases under the respective lease agreements.

Critical Accounting Estimates

We have identified our critical accounting policies, the application of which may materially affect the financial statements, either because of the significance of the financials statement item to which they relate, or because they require management's judgment in making estimates and assumptions in measuring, at a specific point in time, events which will be settled in the future. The critical accounting policies, judgments and estimates which management believes have the most significant effect on the financial statements are set forth below:

a) Estimates. Our management routinely makes judgments and estimates about the effect of matters that are inherently uncertain. As the number of variables and assumptions affecting the future resolution of the uncertainties increase, these judgments become even more subjective and complex. Although we believe that our estimates and assumptions are reasonable, actual results may differ significantly from these estimates. Changes in estimates and assumptions based upon actual results may have a material impact on our results of operation and/or financial condition.

b) Stock-based Compensation. The Company records stock-based compensation in accordance with ASC 718, "Compensation - Stock Compensation" using the fair value method. All transactions in which goods or services are the consideration received for the issuance of equity instruments are accounted for based on the fair value of the consideration received or the fair value of the equity instrument issued, whichever is more reliably measurable.

c) Income Taxes. We have current income tax assets recorded in our financial statements that are based on our estimates relating to federal and state income tax benefits. Our judgments regarding federal and state income tax rates, items that may or may not be deductible for income tax purposes and income tax regulations themselves are critical to the Company's financial statement income tax items.

d) Valuation. The critical accounting policies governing the valuation process outline the methodologies, assumptions, and criteria used to determine the fair value of land and mining rights. These policies ensure consistency, accuracy, and compliance with accounting standards such as ASC 360 for land and ASC 930 for mining rights.

Evaluation of Disclosure Controls and Procedures

At the end of the period covered by this report, an evaluation was carried out under the supervision of, and with the participation of, the Company's Management, including the Chief Executive Officer and Chief Financial Officer, of the effectiveness of the design and operation of the Company's disclosure controls and procedures (as defined in Rule 13a - 15(e) and Rule 15d - 15(e) of the Securities and Exchange Act of 1934, as amended). Based on that evaluation, the Chief Executive Officer and Chief Financial Officer have concluded that as of the end of the period covered by this report, the Company's disclosure controls and procedures were adequately designed and effective in ensuring that information required to be disclosed by the Company in its reports that it files or submits to the SEC under the Exchange Act, is recorded, processed, summarized and reported within the time period specified in applicable rules and forms.

Management's Report on Internal Control over Financial Reporting

The Company's management is responsible for establishing and maintaining adequate internal control over financial reporting. The Company's internal control over financial reporting is a process designed under the supervision of its Chief Executive Officer and Chief Financial Officer to provide reasonable assurance regarding the reliability of financial reporting and the preparation of the Company's financial statements for external reporting in accordance with accounting principles generally accepted in the United States of America. Management assessed the effectiveness of our internal control over financial reporting as of December 31, 2025, using criteria established in Internal Control-Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission ("COSO") and concluded that internal control over financial reporting was effective as of December 31, 2025, based on these criteria.

This Annual Report does not include an attestation report of the Company's registered public accounting firm regarding internal control over financial reporting because the Company is a Smaller Reporting Company and is not required to provide such report.

Changes in internal controls over financial reporting

On April 10, 2025, the Company entered into a services agreement with Ascent CFO Solutions, LLC to provide outsourced financial consulting services. This engagement was intended to enhance the Company's technical accounting oversight and financial reporting processes and to remediate the material weakness previously identified in the Company's Annual Report on Form 10-K/A for the year ended December 31, 2024. Management evaluated the remediation efforts and concluded that the previously identified material weakness had been remediated as of December 31, 2025.

Other than the remediation actions described above, there were no changes in the Company's internal control over financial reporting during the fourth quarter ended December 31, 2025 that have materially affected, or are reasonably likely to materially affect, the Company's internal control over financial reporting.