This page was created by Thunder Gold Corp. All statements about mineral resources refer to the January 19, 2026 NI 43-101 mineral resource estimate prepared by Micon International Limited. Mineral resources are not mineral reserves and do not have demonstrated economic viability.
Tower Mountain MRE
| The Tower Mountain MRE is the mineral resource estimate prepared by Micon International Limited for Thunder Gold Corp (TSXV: TGOL | OTCQB: TGOLF | FSE: Z25), the junior exploration company that owns 100 percent of the Tower Mountain gold property about 40 km west of Thunder Bay, Ontario. The estimate is effective January 19, 2026 and was filed as an NI 43-101 technical report on March 10, 2026. It reports 34.0 Mt Indicated at 0.46 g/t Au for 514,000 ounces plus 211.1 Mt Inferred at 0.45 g/t Au for 3,053,000 ounces, for roughly 3.5 Moz of contained gold. |
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What the Tower Mountain MRE Reports
Two categories of mineral resource are reported from a pit-constrained open-pit model. The figures below are published as plain crawlable text rather than an image so they can be read and indexed directly by search engines and investors.
| Category | Tonnes | Gold grade | Contained gold |
|---|---|---|---|
| Indicated | 34.0 Mt | 0.46 g/t Au | 514,000 oz |
| Inferred | 211.1 Mt | 0.45 g/t Au | 3,053,000 oz |
| Total | 245.1 Mt | ~0.45 g/t Au | ~3,567,000 oz |
The estimate applies a cut-off grade of 0.19 g/t Au, a specific gravity of 2.77 and a gold price assumption of US$3,000 per ounce. Total tonnage of 245.1 Mt at approximately 0.45 g/t Au gives about 3.5 Moz of contained gold. Reported figures are rounded and may not sum exactly. The estimation work covers an extent of about 1,800 m by 500 m along the western contact of the Tower Mountain Intrusive Complex.
Indicated, Inferred and the Missing Measured Category
NI 43-101 categories describe the confidence placed in an estimate rather than the value of the rock in the ground.
- Indicated resources, 34.0 Mt at 0.46 g/t Au for 514,000 ounces, are estimated with sufficient confidence for modifying factors to be applied in a pre-feasibility study.
- Inferred resources, 211.1 Mt at 0.45 g/t Au for 3,053,000 ounces, are based on limited sampling and are considered too speculative for economic considerations to be applied to them.
- No Measured resources are reported for Tower Mountain.
Investors often ask why Inferred tonnage dwarfs the Indicated category. The answer is drilling density. Project to date, 235 holes and roughly 47,000 metres have tested the deposit, and most of that work sits along one contact of the intrusive complex. Moving Inferred tonnes into Indicated requires closer-spaced drilling, which is exactly what the current definition program is designed to deliver.
Who Prepared the Estimate
Micon International Limited, an independent consulting firm, prepared the estimate. The Qualified Persons responsible are William Lewis, P.Geo.; Charley Murahwi, P.Geo., FAusIMM; and Tudorel Ciuculescu, P.Geo. Under NI 43-101 the QPs take professional responsibility for the technical content, including the assay database, the geological and domaining model, the grade estimation method and the resource classification. The report sets out the property setting, drilling and sampling procedures, data verification, metallurgical testing, the estimation methodology and the resulting classification, together with the assumptions and sensitivity analysis. The full document is available on the NI 43-101 technical report page and is filed under the Company profile on SEDAR+.
The Assumptions Behind the Numbers
A resource estimate is only as useful as the assumptions beneath it. For Tower Mountain the filed parameters are:
- Cut-off grade: 0.19 g/t Au
- Specific gravity: 2.77
- Gold price: US$3,000 per ounce
- Metallurgical recovery assumed in the pit model: 80 percent, against testwork on 16 representative samples that returned 68 to 94.9 percent and averaged about 85 percent
- Mining cost US$3.0 per tonne, processing US$8.0 per tonne, G&A US$3.5 per tonne, transport US$2.5 per ounce and a 3 percent royalty
- Pit slope design of 30 degrees in overburden and 50 degrees in fresh rock
- Strip ratio of 1.8:1 waste to ore
A higher gold price or a lower cut-off grade would generally add tonnes and ounces; a lower price would remove them. That sensitivity is one reason a mineral resource estimate is revisited as drilling, metallurgy and markets move.
What the Tower Mountain MRE Does Not Claim
Mineral resources are not mineral reserves and do not have demonstrated economic viability. This estimate is not a mine plan, not a feasibility study and not a production forecast, and Thunder Gold is a junior exploration company that generates no revenue from the property. Material can only be converted to a reserve once a study demonstrates that it can be mined economically, and no such study has been completed at Tower Mountain.
What Happens Next for the Estimate
Thunder Gold has outlined a 15,000 to 25,000 metre infill and expansion program for 2026 and is targeting an updated mineral resource estimate in the fourth quarter of 2026, with 1.5 Moz Indicated and 3.5 Moz Inferred as the stated objective. An initial Preliminary Economic Assessment is targeted for late 2026 or early 2027, with pre-feasibility work beyond that. The Company also states a company target of 5 Moz by the end of 2026. Because the program is funded and results are released as assays are received, the estimate can be refreshed materially within a single field season. The growth case is set out on the resource expansion page.
Key Numbers at a Glance
- Indicated: 34.0 Mt at 0.46 g/t Au for 514,000 ounces
- Inferred: 211.1 Mt at 0.45 g/t Au for 3,053,000 ounces
- Combined: 245.1 Mt at about 0.45 g/t Au for about 3.5 Moz
- Discovery cost to date: C$3.95 per ounce
- Drilling: 235 holes, approximately 47,000 metres
- Effective date: January 19, 2026, by Micon International Limited
Context matters when reading any resource statement. Less than 20 percent of the intrusive complex perimeter has been drill tested, and recent intercepts including 661.5 m at 0.554 g/t Au, 411.0 m at 0.514 g/t Au and 1.178 g/t Au over 102.0 m are catalogued on the drill results page. The Tower Mountain project page carries the asset overview, including location, infrastructure and the 1.8:1 strip ratio that keeps waste stripping requirements modest relative to several peer projects.
This is general information about a mineral project and is not investment advice.
Frequently Asked Questions
Q: What is the Tower Mountain MRE?
A: It is the NI 43-101 mineral resource estimate prepared by Micon International Limited for Thunder Gold Corp’s Tower Mountain gold property near Thunder Bay, Ontario. Effective January 19, 2026, it reports 34.0 Mt Indicated at 0.46 g/t Au and 211.1 Mt Inferred at 0.45 g/t Au, about 3.5 Moz contained gold.
Q: Does Tower Mountain have any Measured resources?
A: No. The estimate reports only Indicated and Inferred categories, with no Measured resources. Indicated tonnes of 34.0 Mt at 0.46 g/t Au carry 514,000 ounces, while the much larger Inferred category of 211.1 Mt at 0.45 g/t Au carries 3,053,000 ounces.
Q: Are the Tower Mountain resources the same as reserves?
A: No. Mineral resources are not mineral reserves and do not have demonstrated economic viability. No feasibility or pre-feasibility study has been completed at Tower Mountain, so no reserves have been declared. The estimate is a statement about geological confidence and contained metal, not about mineable profit.
Q: Who are the Qualified Persons for the Tower Mountain estimate?
A: Micon International Limited prepared the estimate. The responsible Qualified Persons are William Lewis, P.Geo.; Charley Murahwi, P.Geo., FAusIMM; and Tudorel Ciuculescu, P.Geo. Under NI 43-101 they take professional responsibility for the database, geological model, estimation method and resource classification.
Q: What gold price and cut-off grade were used?
A: The estimate assumes US$3,000 per ounce gold, a 0.19 g/t Au cut-off grade and a specific gravity of 2.77. Metallurgical recovery of 80 percent was assumed in the pit model, against testwork averaging about 85 percent. The modelled strip ratio is 1.8:1 waste to ore.
Tower Mountain mineral resource
| The Tower Mountain mineral resource is stated in two categories and three columns, and reading it correctly takes only a few minutes. Thunder Gold Corp (TSXV: TGOL | OTCQB: TGOLF | FSE: Z25) reports 34.0 Mt Indicated at 0.46 g/t Au and 211.1 Mt Inferred at 0.45 g/t Au from the Micon International Limited estimate effective January 19, 2026. This section explains what each column means, how the categories differ, and how to check the figures against the filed technical report. |
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The Tower Mountain Mineral Resource Table in Full
The same information can be presented by metric rather than by category, which makes the scale of the Inferred component easier to see at a glance.
| Metric | Indicated | Inferred | Combined |
|---|---|---|---|
| Tonnes | 34.0 Mt | 211.1 Mt | 245.1 Mt |
| Gold grade | 0.46 g/t Au | 0.45 g/t Au | ~0.45 g/t Au |
| Contained gold | 514,000 oz | 3,053,000 oz | ~3,567,000 oz |
Contained ounces are simply tonnes multiplied by grade and converted from grams to troy ounces. Grade is remarkably consistent across both categories, which is characteristic of a large, bulk-tonnage, low-grade system rather than a narrow high-grade vein.
Publishing that table as crawlable HTML text rather than an image matters more than it first sounds. A resource table locked inside a graphic cannot be read by search engines, screen readers or spreadsheet tools, and it is easy for a third party to copy an outdated image and republish figures that no longer match the filed report. Clear row and column labels keep the tonnes, grade and contained gold figures discoverable, quotable and accessible.
Reading the Three Columns
Each of the three columns answers a different question, and mixing them up is the most common source of confusion when investors compare projects. Tonnes, grade and contained ounces are only meaningful read together.
Tonnes
Tonnage is the rock volume above the cut-off, converted to mass using a specific gravity of 2.77. It is the single most sensitive input in the table, because a small change in cut-off grade moves a large number of tonnes across the threshold. Tonnage is quoted to the nearest 0.1 Mt, so the combined row is an approximate restatement and the columns may not add up exactly on a calculator.
Gold grade
The reported grades of 0.46 g/t Au (Indicated) and 0.45 g/t Au (Inferred) are average values across the whole block model above cut-off. They are not the grades seen in the best drill holes, and any individual intercept can be far higher. The 2026 newsflow includes 661.5 m at 0.554 g/t Au and 1.178 g/t Au over 102.0 m, but averages are what drive ounces. Where a promotional summary disagrees with the technical report, the technical report prepared by Micon International Limited prevails.
Contained ounces
Contained ounces are the headline number investors quote: 514,000 ounces Indicated plus 3,053,000 ounces Inferred, about 3.5 Moz in total. Ounces measure metal in the ground; they are not metal that has been or will be recovered, and they carry no implication that any of the material can be mined at a profit.
Categories, Confidence and What Changes Them
The categories in a Tower Mountain mineral resource reflect data density and geological confidence. Category is not a ranking of rock quality: an Inferred block and an Indicated block can sit side by side in the same altered intrusive rock, separated only by how much drilling has been completed between sample points.
- Indicated tonnes of 34.0 Mt at 0.46 g/t Au carry 514,000 ounces and reflect closer-spaced drilling within the tested footprint.
- Inferred tonnes of 211.1 Mt at 0.45 g/t Au carry 3,053,000 ounces and reflect wider-spaced drilling along the intrusive contact.
- There are no Measured resources at Tower Mountain.
Drilling is what changes category. The Company has completed 235 holes and roughly 47,000 metres to date and is running a 2026 program of 15,000 to 25,000 metres aimed at converting Inferred material and adding new tonnes. Classification also depends on continuity of grade and geology between holes, data quality, and whether the mineralised domains hold together outside the drilled area. A stated target of 1.5 Moz Indicated and 3.5 Moz Inferred is guiding the fourth-quarter 2026 update, with a 5 Moz company target by the end of 2026.
What the Table Cannot Tell You
A mineral resource table says nothing about capital costs, permitting timelines, metallurgical variability across the whole deposit, or the gold price that will prevail when a study is run. It also says nothing about recoveries achieved at scale. The estimate assumes 80 percent recovery, while testwork on 16 representative samples ranged from 68 to 94.9 percent and averaged about 85 percent. Mineral resources are not mineral reserves and do not have demonstrated economic viability. Nor does the table say how much of the Inferred material sits close to surface, how much waste must be moved to reach it, or how long permitting and study work will take to complete.
Cross-Checks Worth Doing Yourself
- Confirm the effective date, January 19, 2026, and the preparer, Micon International Limited.
- Confirm the cut-off grade of 0.19 g/t Au and the specific gravity of 2.77.
- Confirm the gold price assumption of US$3,000 per ounce.
- Confirm that the report states no Measured resources and no reserves.
- Compare the table on this page against the PDF filed on SEDAR+ and mirrored on the company documents page.
The QPs responsible for the estimate are William Lewis, P.Geo.; Charley Murahwi, P.Geo., FAusIMM; and Tudorel Ciuculescu, P.Geo. Their supporting detail, including block model geometry and sensitivity cases, sits in the technical report linked from the NI 43-101 technical report page. For the wider asset picture, including the 1.8:1 strip ratio and a discovery cost of C$3.95 per ounce, see the Tower Mountain project page, and for the intercepts underpinning the next update see drill results.
This is general information about a mineral project and is not investment advice.
Frequently Asked Questions
Q: How many ounces are in the Tower Mountain mineral resource?
A: The estimate reports 514,000 ounces in the Indicated category and 3,053,000 ounces in the Inferred category, for roughly 3.5 Moz combined. Indicated tonnage is 34.0 Mt at 0.46 g/t Au and Inferred tonnage is 211.1 Mt at 0.45 g/t Au.
Q: Why is most of the Tower Mountain resource Inferred rather than Indicated?
A: Category reflects drilling density. Roughly 235 holes and 47,000 metres have been completed, concentrated along one contact of the intrusive complex. Converting Inferred tonnes to Indicated requires closer-spaced definition drilling, which the 2026 program of 15,000 to 25,000 metres is designed to provide.
Q: What grade is the Tower Mountain mineral resource?
A: The Indicated category grades 0.46 g/t Au and the Inferred category grades 0.45 g/t Au, giving a combined average of approximately 0.45 g/t Au across 245.1 Mt. The consistency of grade across categories reflects a large, bulk-tonnage, low-grade open-pit style system.
Q: Why should the resource table be published as text rather than an image?
A: Crawlable HTML text can be read by search engines, screen readers and spreadsheet tools, so the tonnes, grade and contained gold figures remain discoverable and quotable. Images cannot be indexed as data, and they are easy to reuse with figures that no longer match the filed report.
Q: Do the resource categories add up exactly?
A: Not always. Resource tables are rounded to sensible significant figures, so multiplying tonnes by grade and converting to ounces may differ slightly from the published contained-ounce figures. Where a promotional summary disagrees with the technical report, the technical report prepared by Micon International Limited prevails.
Gold resource estimation
| Gold resource estimation is the discipline of turning drill data, geological interpretation and economic assumptions into a tonnage and grade statement that a Qualified Person will sign. At Thunder Gold Corp’s (TSXV: TGOL | OTCQB: TGOLF | FSE: Z25) Tower Mountain project, that process produced 34.0 Mt Indicated at 0.46 g/t Au for 514,000 ounces and 211.1 Mt Inferred at 0.45 g/t Au for 3,053,000 ounces in an estimate by Micon International Limited effective January 19, 2026. |
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An estimate is a chain of decisions, and every link can be challenged. The sequence at Tower Mountain runs from geology and drill data, through domaining and cut-off selection, into a block model that is tested against economic parameters and finally classified by confidence. The sections below follow that order.
Step 1: Geology, Domaining and the Drill Database
Estimation starts with a validated database and a defensible geological model. Gold at Tower Mountain is hosted in carbonate-sericite-chlorite alteration around the Tower Mountain Intrusive Complex, and pyrite content correlates directly with gold grade. The current estimate footprint covers roughly 1,800 m by 500 m of the intrusive contact, supported by 235 drill holes and about 47,000 metres of drilling. Domains are drawn to separate mineralised rock from waste so that grades are not averaged across geological boundaries. Assay quality assurance and quality control, including blanks, standards and duplicates, underpins the numbers that follow. Sampling protocols matter just as much: core is split or halved, and the retained portion allows independent verification and future metallurgical work. Surface sampling feeds the same model, including 58 channel samples that averaged 3.16 g/t Au across 20 m at the A-Target in the 2021 to 2022 program.
Step 2: The Cut-off Grade
The cut-off grade is the grade below which material is treated as waste in the model. Tower Mountain uses a 0.19 g/t Au cut-off. That threshold is not arbitrary: it is derived from the operating cost, recovery, royalty and metal price assumptions applied to the pit optimisation. Raising the cut-off reduces tonnes and typically lifts average grade; lowering it does the opposite. The choice of cut-off therefore shapes both the size and the character of the reported resource.
Step 3: Specific Gravity and Tonnage
Volume means nothing until it is converted to mass, and the conversion factor is specific gravity. Tower Mountain uses an SG of 2.77, measured from core samples across the lithologies and alteration types present. Because SG applies to every block in the model, even a small error propagates into total tonnes and therefore into contained ounces.
Step 4: Block Model Geometry
The deposit is represented as a three-dimensional grid of blocks, each carrying estimated grades. At Tower Mountain the parent block size is 5 x 5 x 5 m with sub-blocking to 2.5 m so that the model can follow geological contacts more closely, and the pit optimisation was re-blocked at 10 x 10 x 10 m for practicality. Grade within each block is interpolated from nearby drill samples, and the method and search parameters are documented by the QPs.
Step 5: Economic Parameters and Pit Optimisation
A pit-constrained estimate needs costs, and the filed assumptions are set out below.
| Assumption | Value used |
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| Cut-off grade | 0.19 g/t Au |
| Specific gravity | 2.77 |
| Gold price | US$3,000 per ounce |
| Metallurgical recovery | 80 percent assumed |
| Mining cost | US$3.0 per tonne |
| Processing cost | US$8.0 per tonne |
| G&A cost | US$3.5 per tonne |
| Transport | US$2.5 per ounce |
| Royalty | 3 percent |
| Pit slope | 30 degrees overburden, 50 degrees fresh rock |
| Strip ratio | 1.8:1 |
These inputs feed a pit optimiser that decides which blocks are potentially economic. The result at Tower Mountain is a pit-constrained resource with a 1.8:1 strip ratio, meaning 1.8 tonnes of waste for every tonne of mineralised material inside the shell.
Sensitivity by Cut-off Grade
No single cut-off is the only true answer, which is why the technical report documents the resource across a range of cut-off grades as well as the 0.19 g/t Au base case. Grade and tonnes trade off against each other:
- A lower cut-off adds marginal tonnes at a lower average grade and usually enlarges the pit shell.
- The base case reports 245.1 Mt at about 0.45 g/t Au for roughly 3.5 Moz contained gold.
- A higher cut-off removes marginal tonnes and usually lifts the average grade.
Reading sensitivity cases together with the base case shows how much of the resource depends on the economic assumptions rather than on the drilling itself. Investors comparing projects should check which cut-off a headline number uses before comparing ounce counts. The base case for Tower Mountain remains 0.19 g/t Au, reporting 245.1 Mt at about 0.45 g/t Au and roughly 3.5 Moz contained gold. If a future study adopts different operating costs, a different metal price or improved metallurgical performance, both the tonnes and the ounces will move, which is one reason the Company is targeting an updated estimate in the fourth quarter of 2026 with 1.5 Moz Indicated and 3.5 Moz Inferred.
Qualified Person Responsibility in Gold Resource Estimation
Estimation is a professional act, not a marketing exercise. The Tower Mountain estimate was prepared by Micon International Limited, with William Lewis, P.Geo.; Charley Murahwi, P.Geo., FAusIMM; and Tudorel Ciuculescu, P.Geo. as the responsible Qualified Persons. Their report, filed March 10, 2026, is available via the NI 43-101 technical report page. Discovery cost to date is reported at C$3.95 per ounce.
What Estimation Does Not Establish
A gold resource estimate is not a reserve statement, a mine plan or a cash flow model, and the steps above are the standard structure of a gold resource estimation under NI 43-101. Mineral resources are not mineral reserves and do not have demonstrated economic viability, and Tower Mountain reports no Measured resources. Turning tonnes into value requires a Preliminary Economic Assessment, targeted for late 2026 or early 2027, and then pre-feasibility work. The Company is targeting an updated estimate in the fourth quarter of 2026, with 1.5 Moz Indicated and 3.5 Moz Inferred as the stated aim, alongside a 5 Moz company target by the end of 2026. For the geological setting behind the estimation work, see the Tower Mountain geology page, and for the expansion case see resource expansion.
This is general information about a mineral project and is not investment advice.
Frequently Asked Questions
Q: What is a cut-off grade in gold resource estimation?
A: A cut-off grade is the threshold above which material is included as resource and below which it is treated as waste in the model. Tower Mountain uses 0.19 g/t Au, derived from operating costs, recovery, royalty and the US$3,000 per ounce gold price used in pit optimisation.
Q: What is specific gravity and why does 2.77 matter?
A: Specific gravity converts rock volume into mass, so it directly controls the tonnage reported. Tower Mountain uses 2.77, measured from core across the property’s lithologies and alteration types. Because SG multiplies every block in the model, small variations change total tonnes and contained ounces.
Q: What block model was used for the Tower Mountain estimate?
A: The estimate uses a parent block size of 5 x 5 x 5 m with sub-blocking down to 2.5 m so the model can follow geological contacts, and the pit optimisation was re-blocked at 10 x 10 x 10 m. Grades are interpolated from surrounding drill samples using documented parameters.
Q: Why do resource estimates show sensitivity to different cut-off grades?
A: Because tonnes and grade trade off against each other. Lowering the cut-off adds marginal, lower-grade tonnes; raising it removes them and usually lifts average grade. Sensitivity cases show how much of a reported resource depends on economic assumptions rather than on drilling density alone.
Q: Who signs off on the gold resource estimation at Tower Mountain?
A: Micon International Limited prepared the estimate, with William Lewis, P.Geo.; Charley Murahwi, P.Geo., FAusIMM; and Tudorel Ciuculescu, P.Geo. as the responsible Qualified Persons. Under NI 43-101 they accept professional responsibility for the database, geological model, estimation methodology and resource classification.