First Mining Gold (TSX: FF) extends Miroir mineralization with new Quebec drill results

First Mining Gold Corp. (TSX: FF; OTCQX: FFMGF; Frankfurt: FMG) has reported initial 2026 drilling results from the Miroir discovery at its 100%-owned Duparquet Gold Project in Quebec, including 5.26 grams per tonne of gold over 19.55 metres in hole DUP26-093. That interval contained 7.58 g/t over 12.95 metres and 21.80 g/t over one metre, while hole DUP26-096 returned 3.43 g/t over 28 metres including 10.36 g/t over 7.2 metres. The company says recent drilling has extended known Miroir mineralization to approximately 220 metres of strike and expanded it at depth. The results strengthen the geological case for Miroir, but they do not yet represent additional mineral-resource ounces, reserves or a revised economic valuation for Duparquet.

First Mining began its 15,000 metre 2026 Duparquet drilling programme in May, focusing on exploration and resource advancement. The company has now initiated an updated resource model incorporating drilling completed since the current mineral-resource estimate, with approximately 48,000 metres drilled across established resource areas and emerging targets since that earlier estimate.

Why are the Miroir intercepts important without yet being new mineral-resource ounces?

Individual drill intersections reveal grade and mineralization over the path of a drill hole, but mineral resources require enough drilling to establish geological continuity, geometry, density and confidence across a three-dimensional volume. One strong intersection can therefore improve a geological interpretation without automatically adding a defined quantity of economically recoverable gold.

Miroir was discovered only in 2024 and was expanded through subsequent drilling in 2025 and 2026. The latest holes extend the interpreted system eastward and down plunge while strengthening evidence that mineralization continues beyond earlier drilling.

The reported 19.55 metre and 28 metre intervals are drill lengths. Investors should not automatically assume those dimensions equal true mineralized width unless geological modelling establishes the orientation of the mineralized body relative to the holes.

What matters next is whether additional drilling demonstrates enough continuity to include Miroir in a future resource estimate. If the grades persist across multiple sections and sufficient geometry can be established, Miroir could become more important to Duparquet than any single headline intercept implies.

How large is Duparquet before Miroir is potentially added to the resource model?

The Duparquet project already contains approximately 3.44 million ounces of gold in the Measured and Indicated categories at an average grade of 1.55 g/t, plus around 2.64 million ounces of Inferred resources at approximately 1.62 g/t. The consolidated project includes Central Duparquet, Dumico, Pitt Gold, Duquesne and several historical mining areas along the Destor-Porcupine Fault Zone.

That existing resource base means Miroir is an expansion opportunity within a large project rather than the discovery on which Duparquet depends entirely. Additional ounces can still matter because they may alter mine sequencing, extend operating life or provide higher-grade material that improves future economics.

First Mining’s updated model is particularly relevant because approximately 48,000 metres of drilling have been completed since the current resource estimate. That volume of new data extends well beyond the latest four highlighted holes and gives the company an opportunity to revisit several zones simultaneously.

A new resource estimate will provide a much stronger basis for valuation than aggregating individual intercepts. Investors will be able to compare total ounces, grade distribution and resource classification with the current model instead of relying on isolated drill results.

Why should Duparquet’s 2023 PEA not simply be recalculated using today’s higher gold price?

The 2023 preliminary economic assessment used a base-case gold price of US$1,800 per ounce and produced an after-tax net present value at a 5% discount rate of C$588 million and an after-tax internal rate of return of 18%. It outlined average annual recovered production of about 233,000 ounces across an 11-year mine life, with initial capital estimated at C$706 million and life-of-mine all-in sustaining costs of US$976 per ounce.

Gold prices are now far above the PEA assumption, creating an intuitively more favorable revenue environment. It would nevertheless be misleading to substitute a current spot gold price into the old study and present the resulting value as an updated NPV.

Construction costs, labor, equipment, consumables, foreign exchange and mine plans have also changed since 2023. The project’s resource base is being updated, while the PEA itself includes inferred mineral resources that are considered too speculative geologically to be treated as mineral reserves.

A refreshed economic study can incorporate both higher gold prices and current costs. Until that happens, the 2023 PEA remains useful for understanding scale and capital intensity, not as a current valuation model.

Does First Mining have enough liquidity to keep advancing Duparquet while Springpole also moves forward?

First Mining reported C$40.5 million of cash and marketable securities at June 30, alongside a Seva Mining equity investment valued at approximately C$29 million and an interest in PC Gold valued at C$14.3 million. The company therefore has meaningful financial resources for exploration and project-development activity compared with many junior gold developers.

That balance is still small compared with the construction capital implied by Duparquet’s previous PEA. The C$706 million initial-capital estimate from 2023 was more than 17 times First Mining’s June cash and marketable securities balance.

The comparison does not mean First Mining needs to fund a future mine entirely from corporate cash. Large mine developments typically use combinations of debt, equity, streaming, royalties, joint ventures or strategic partnerships.

It does show why resource growth alone is not the final investment question. First Mining has to advance technical studies, permitting and financing structures while also developing its Springpole Gold Project in Ontario, where it has achieved major environmental and Indigenous partnership milestones during 2026.

How did First Mining shares react to the new Miroir drill results?

First Mining shares closed at C$0.91 on September 10, down 2.15% after trading as high as C$0.97 during the session. Volume reached approximately 4.44 million shares, more than double the roughly 1.97 million shares traded on September 9.

The decline occurred during a weaker Canadian market session, with the S&P/TSX Composite falling as higher bond yields and commodity-market pressure weighed on sentiment. That broader context makes it inappropriate to treat the 2.15% decline as a straightforward rejection of the drill results.

Exploration results can also create volatile reactions because investors may have already anticipated strong assays or may focus on whether a release changes the resource rather than the quality of an isolated intercept.

For First Mining, the stronger catalyst is likely to be the updated Duparquet resource model. That document can establish whether several years of drilling, including Miroir, translate into additional ounces, grade improvements or geological confidence that materially changes future mine planning.

What evidence would show that Miroir has become economically important to Duparquet?

The first step is continued drilling demonstrating that the current 220 metre strike extent expands further and remains mineralized at useful grades. Pending assays from the 2026 programme will provide additional evidence.

The second is inclusion in an updated mineral-resource model. Investors can then determine how many ounces Miroir contributes and in which confidence category, rather than attempting to infer volume from drill widths.

A subsequent economic study would provide the most meaningful test. If Miroir adds higher-grade or strategically located material that improves mine sequencing, throughput or early cash flow, its value could exceed the simple number of ounces added.

First Mining has produced strong drill numbers at Miroir, but the company is correctly still in the geological-definition stage. The headline intersection is interesting; the resource update will determine whether it is financially consequential.

Key takeaways on First Mining Gold’s Miroir drilling at Duparquet

• First Mining reported 5.26 g/t gold over 19.55 metres in DUP26-093.
• The interval included 7.58 g/t over 12.95 metres and 21.80 g/t over one metre.
• DUP26-096 returned 3.43 g/t over 28 metres, including 10.36 g/t over 7.2 metres.
• Miroir’s known strike extent has expanded to approximately 220 metres.
• First Mining is targeting around 15,000 metres of Duparquet drilling in 2026.
• Approximately 48,000 metres have been drilled since the current resource estimate.
• Duparquet currently contains about 3.44 million Measured and Indicated ounces and 2.64 million Inferred ounces.
• The 2023 PEA used a US$1,800 per ounce gold price and estimated C$706 million of initial capital.
• First Mining held C$40.5 million of cash and marketable securities at June 30.
• The updated resource model, not a single drill interval, will determine whether Miroir materially changes Duparquet.