Indicate by check mark whether the registrant
files or will file annual reports under cover of Form 20-F or Form 40-F.
Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
Exhibit 99.1
First Mining Reports
5.26 g/t Au over 19.55 m as Drilling Expands Miroir Discovery at the Duparquet Project
| • | DUP26-093 returns 5.26 g/t Au over 19.55 m, including
7.58 g/t over 12.95 m and including 21.80 g/t over 1.0 m |
| • | DUP26-096 returns 3.43 g/t Au over 28.0 m, including 10.36
g/t Au over 7.20 m |
VANCOUVER,
BC, Sept. 10, 2026 /CNW/ - First Mining Gold Corp. ("First Mining" or the "Company") (TSX: FF) (OTCQX:
FFMGF) (FRANKFURT: FMG) is pleased to announce initial results from the 2026 exploration drilling program at its Duparquet Gold Project
("Duparquet Project" or the "Project") located in the Abitibi region of Quebec, Canada. The Company
commenced its 2026 drilling program at the Project in May 2026 and is targeting to complete an estimated 15,000 m of drilling focused
on exploration and resource advancement opportunities. The results reported here are primarily from the Miroir target, a high-priority
discovery zone first identified by First Mining in its 2024 drill program and further delineated and advanced through follow-up drilling
in 2025 and 2026.
| • | Drill holes DUP26-093 to DUP26-096 successfully targeted
an important easterly and down plunge extension and returned the following highlights: DUP26-093 returned 5.26 g/t Au over 19.55 m, including
7.58 g/t Au over 12.95 m, and including 21.80 g/t Au over 1.0 m |
| • | DUP26-095 returned 3.36 g/t Au over 15.8 m, including 15.10
g/t Au over 2.0 m, and 3.54 g/t Au over 4.2 m, including 7.28 g/t Au over 1.0 m |
| • | DUP26-096 returned 3.43 g/t Au over 28.0 m, including 10.36
g/t Au over 7.2 m, and 2.99 g/t Au over 4.6 m, as well as 4.90 g/t Au over 2.7 m |
In addition, drill hole DUP26-092 returned 3.33 g/t
Au over 5.0 m, including 7.20 g/t Au over 1.0 m, and validated an extension of the mineralization towards the west and at depth (See Table
1 and 3 for details). The deposit remains open in all directions for additional exploration.
"We continue to be very active with our exploration
program at Duparquet and are excited to announce the initial results from our 2026 program. The continued high-grade results from Miroir
are very encouraging and demonstrate the potential of this target to become an important contributor to future resource growth and development
planning at our Duparquet Project," stated Dan Wilton, CEO of First Mining. "We are pleased with the progress made through our
successive drill programs and the continued expansion of mineralization at Miroir. With additional results still pending, we look forward
to further advancing this target and evaluating its potential within the broader Duparquet Project."
In 2025, drilling at the Miroir target tested mineralization
over a strike length of 150 m and to a vertical depth of 250 m. Building on these results, the 2026 exploration program has focused on
testing extensions of the mineralized zone, with initial results received to date extending the known strike length to approximately 220
m, while also extending mineralization at depth in areas to the east and west (Figures 1 and 2).
Drilling at the Miroir target continues to demonstrate
the potential for further expansion of mineralization at the Duparquet Project, with the multiple robust gold intercepts returned to date
supporting the growing scale and continuity of the mineralized zone. The 2026 drilling program has continued to test the target along
strike and at depth, further advancing the Company's understanding of the geometry and extent of mineralization. Additional drill results
remain pending.
2026 Drilling and Resource Model Advancement
The 2026 drilling program at the Duparquet Project
commenced in May 2026 and are continuing into Q4 2026, with the Company targeting the completion of a 15,000 m drilling campaign focused
on key exploration and resource advancement opportunities. Assay results from the ongoing programs continue to be received, with additional
results and interpretations to be disclosed in future updates as ongoing integration and modelling work continues.
In addition, First Mining has initiated an update
to the Duparquet Project resource model to incorporate drilling completed since the current Mineral Resource Estimate, which has an effective
date of September 12, 2022. Since that time, the Company has completed 48,000m of drilling across the Project at established resource
areas and emerging exploration targets. The updated resource model will incorporate this new drilling and provide an opportunity to evaluate
the potential impact of the additional data on the Project's mineral resource and geological understanding.
Figure 1: Plan view map, highlighting the Miroir Target’s
location in relation to known mineralized and exploration zones in the Central Duparquet-Dumico area
Figure 2: Miroir Long Section, highlighting recent
drilling as well as the open-ended potential of the Miroir interpreted structure
The latest reported assays represent approximately
1,553 m of drilling from a total of 2,994 m across 11 drill holes drilled at the Miroir target this year. These holes were focused on
advancing the understanding of mineralization controls at Miroir and extending the target depth while testing the down-dip potential.
Assay highlights are provided in Table 1, with the full list of assay results presented in Table 3 and drill collar details in Table 4.
Table 1: Latest Significant 2026 Drill Intercepts
| Hole ID |
|
From (m) |
To (m) |
Length (m) |
Grade (Au g/t) |
| DUP26-092 |
|
155.5 |
156.5 |
1.0 |
11.80 |
| DUP26-092 |
|
181.0 |
186.0 |
5.0 |
3.33 |
| DUP26-092 |
inc. |
181.0 |
182.0 |
1.0 |
7.20 |
| DUP26-092 |
|
190.0 |
196.2 |
6.2 |
2.61 |
| DUP26-093 |
|
182.0 |
201.55 |
19.55 |
5.26 |
| DUP26-093 |
inc. |
185.9 |
198.85 |
12.95 |
7.58 |
| DUP26-093 |
and inc. |
196.0 |
197.0 |
1.0 |
21.80 |
| DUP26-095 |
|
1.2 |
17.0 |
15.8 |
3.36 |
| DUP26-095 |
inc. |
2.0 |
4.0 |
2.0 |
15.10 |
| DUP26-095 |
|
170.3 |
174.5 |
4.2 |
3.54 |
| DUP26-095 |
inc. |
172.0 |
173.0 |
1.0 |
7.28 |
| DUP26-0961 |
|
2.0 |
15.0 |
13.0 |
1.89 |
| DUP26-0961 |
|
192.3 |
195.6 |
3.3 |
1.56 |
| DUP26-0961 |
|
224.2 |
228.45 |
4.25 |
1.83 |
| DUP26-0961 |
|
234.35 |
262.35 |
28.0 |
3.43 |
| DUP26-0961 |
inc. |
252.0 |
259.2 |
7.2 |
10.36 |
| DUP26-0961 |
|
266.5 |
271.1 |
4.6 |
2.99 |
| DUP26-0961 |
|
347.0 |
349.7 |
2.7 |
4.90 |
| 1 Assay results for the final 12 samples of drill hole DUP26-96 remain pending and are not included in the results reported above. |
Additional Details on Miroir
The Miroir target forms an important part of a recently
unlocked exploration advancement area located along the eastern mineralization trend of the Duparquet Project gold deposits. Exploration
of the area also includes the CVD series of deposits as well as open trends to the north and south. The area is thought to represent new
growth opportunities where a strong potential for additional continuity of gold mineralization and discoveries may exist along strike,
down dip, and down plunge.
The 2026 drilling at the Miroir target focused on
further delineating the extent of near-surface mineralization discovered in 2024. In 2025, drilling confirmed multiple near-surface gold
zones and extended the discovery to a vertical depth of 250m which spanned approximately 150 m of strike length. A series of significant
intercepts have been returned at Miroir to date (Table 2), with the most recent drilling continuing to confirm and expand the target area,
extending mineralization to a strike length of 220 m and highlighting multiple near-surface gold zones.
Notable results from the most recent drilling include
drill hole DUP26-093 returning 5.26 g/t Au over 19.55 m from 182.0 m to 201.55 m, including 7.58 g/t Au over 12.95 m, and including 21.80
g/t Au over 1.0 m. Drillhole DUP26-096 returned 3.43 g/t Au over 28.0 m from 234.35 m to 262.35 m, including 10.36 g/t over 7.2 m. These
results continue to demonstrate the potential for multiple, high-quality gold zones within the Miroir target and reinforce its potential
for further growth.
High-grade mineralization at the Miroir target is
associated with coincident brittle deformation within a volcanic package proximal to syenite contacts. Mineralized intercepts are spatially
correlated with northeast-southwest-striking D2 deformation zones that coincide with a geophysically inferred basalt-syenite contact plunging
to the east.
In the most recent drill holes, mineralization is
hosted within a mixed package composed primarily of basalt with syenite clasts. This strongly brecciated unit is silica-altered and contains
2-5% very fine-grained, disseminated to fracture-controlled bronze pyrite. In some areas, the alteration is sufficiently intense that
evidence of the primary textures has been completely overprinted.
Table 2: Previous Disclosure Highlights from the
Miroir target
| Drill Hole |
|
Interval |
Disclosure Date |
| DUP24-048 |
|
3.12 g/t Au over 19.35 m, including 5.47 g/t Au over 9.60 m and including 11.26 g/t Au over 3.0 m |
January 20, 2025 |
| DUP25-052 |
|
2.77 g/t Au over 11.1 m, including 4.36 g/t Au over 6.5 m |
May 28, 2025 |
| DUP25-064 |
|
3.23 g/t Au over 25.9 m, including 11.20 g/t Au over 2.0 m, and including 10.16 g/t Au over 1.4 m |
September 24, 2025 |
| DUP25-078 |
|
2.01 g/t Au over 29.8 m, including 15.70 g/t Au over 0.75 m and 18.20 g/t Au over 1.0 m |
November 10, 2025 |
| DUP25-085 |
|
3.74 g/t Au over 15.5 m and 7.18 g/t over 8.0 m, including 30.58 g/t over 1.65 m |
March 9, 2026 |
| DUP25-090 |
|
4.08 g/t Au over 12.0 m, including 11.20 g/t Au over 1.0 m |
March 9, 2026 |
Table 3: Latest Assay Results from 2026 Drill Program
| Hole ID |
|
From (m) |
To (m) |
Length (m) |
Grade (Au g/t) |
| DUP26-092 |
|
55.0 |
59.0 |
4.0 |
0.79 |
| DUP26-092 |
|
112.1 |
118.4 |
6.3 |
0.57 |
| DUP26-092 |
|
135.0 |
136.0 |
1.0 |
0.49 |
| DUP26-092 |
|
141.0 |
142.0 |
1.0 |
3.11 |
| DUP26-092 |
|
155.5 |
156.5 |
1.0 |
11.80 |
| DUP26-092 |
|
158.0 |
160.0 |
2.0 |
0.83 |
| DUP26-092 |
|
181.0 |
186.0 |
5.0 |
3.33 |
| DUP26-092 |
including |
181.0 |
182.0 |
1.0 |
7.20 |
| DUP26-092 |
|
190.0 |
196.2 |
6.20 |
2.61 |
| DUP26-092 |
|
255.0 |
259.0 |
4.0 |
1.13 |
| DUP26-093 |
|
160.1 |
166.05 |
5.95 |
0.78 |
| DUP26-093 |
|
173.0 |
174.0 |
1.0 |
0.98 |
| DUP26-093 |
|
182.0 |
201.55 |
19.55 |
5.26 |
| DUP26-093 |
including |
185.9 |
198.85 |
12.95 |
7.58 |
| DUP26-093 |
and including |
196.0 |
197.0 |
1.0 |
21.80 |
| DUP26-094 |
|
231.0 |
233.1 |
2.1 |
1.69 |
| DUP26-094 |
|
243.0 |
245.0 |
2.0 |
1.19 |
| DUP26-094 |
|
249.0 |
250.0 |
1.0 |
0.50 |
| DUP26-094 |
|
258.0 |
264.0 |
6.0 |
0.54 |
| DUP26-094 |
|
268.0 |
271.0 |
3.0 |
1.25 |
| DUP26-094 |
|
302.0 |
303.0 |
1.0 |
1.48 |
| DUP26-095 |
|
1.2 |
17.0 |
15.8 |
3.36 |
| DUP26-095 |
including |
2.0 |
4.0 |
2.0 |
15.10 |
| DUP26-095 |
|
170.3 |
174.5 |
4.2 |
3.54 |
| DUP26-095 |
including |
172.0 |
173.0 |
1.0 |
7.28 |
| DUP26-095 |
|
246.0 |
247.0 |
1.0 |
0.54 |
| DUP26-095 |
|
257.89 |
258.6 |
0.71 |
0.89 |
| DUP26-0961 |
|
2.0 |
15.0 |
13.0 |
1.89 |
| DUP26-0961 |
|
192.3 |
195.6 |
3.3 |
1.56 |
| DUP26-0961 |
|
208.1 |
208.6 |
0.5 |
1.71 |
| DUP26-0961 |
|
213.3 |
214.0 |
0.7 |
1.85 |
| DUP26-0961 |
|
216.8 |
217.45 |
0.65 |
0.54 |
| DUP26-0961 |
|
224.2 |
228.45 |
4.25 |
1.83 |
| DUP26-0961 |
|
234.35 |
262.35 |
28.0 |
3.43 |
| DUP26-0961 |
including |
252.0 |
259.2 |
7.2 |
10.36 |
| DUP26-0961 |
|
266.5 |
271.1 |
4.6 |
2.99 |
| DUP26-0961 |
|
347.0 |
349.7 |
2.7 |
4.90 |
| DUP26-0961 |
|
359.0 |
363.0 |
4.0 |
1.07 |
| * Reported intervals are drilled core lengths. True widths have not yet been determined as the geometry and orientation of the mineralized zones remain under evaluation as exploration drilling continues. Assay values are uncut. |
| ¹ Assay results for the final 12 samples of drill hole DUP26-96 remain pending and are not included in the results reported above. |
Table 4: Latest 2026 Drill Hole Locations
| |
Azimuth (°) |
Dip (°) |
Length (m) |
Easting |
Northing |
| DUP26-092 |
340 |
-63 |
330 |
633531 |
5374046 |
| DUP26-093 |
0 |
-50 |
258 |
633718 |
5374026 |
| DUP26-094 |
0 |
-59 |
324 |
633718 |
5374026 |
| DUP26-095 |
2 |
-48 |
260 |
633670 |
5374020 |
| DUP26-096 |
0 |
-56 |
381 |
633670 |
5374020 |
| Note: Collar coordinates in UTM NAD 83 z17 |
About the Duparquet Gold Project
The Duparquet Project is situated in the Abitibi Greenstone
Belt and is geographically located approximately 50 km northwest of the city of Rouyn-Noranda. The Project benefits from easy access and
proximity to an existing workforce and infrastructure, including road, rail and hydroelectric grid power. The Duparquet Project currently
hosts an NI 43-101 compliant gold resource of 3.44 million ounces in the Measured & Indicated category, grading 1.55 g/t Au, and an
additional 2.64 million ounces in the Inferred category, grading 1.62 g/t Au. First Mining completed a Preliminary Economic Assessment1 ("PEA")
on the Project in 2023.
The Duparquet Project totals approximately 5,800 hectares
focused on an area of 19 km of strike length along the prolific Destor-Porcupine Fault Zone, along with numerous mineralized splays and
influential secondary lineaments. The Duparquet Project includes the past-producing Beattie, Donchester and Duquesne mines as well as
the Central Duparquet, Dumico and Pitt Gold deposits.
| 1 Further details on the Duparquet PEA can be found in the technical report entitled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Gold Project, Quebec, Canada" dated October 20, 2023, which was prepared for First Mining by G Mining Services Inc. in accordance with NI 43-101 and is available under First Mining's SEDAR+ profile at www.sedarplus.ca |
Analytical Laboratory and QA/QC Procedures
All sampling completed by First Mining within its
exploration programs is subject to a Company standard of internal quality control and quality assurance (QA/QC) programs which include
the insertion of certified reference materials, blank materials and a level of duplicate analysis. Core samples from the 2026 drilling
program at Duparquet were sent to AGAT Laboratories, with sample preparation in Val d'Or, Quebec and analysis in Thunder Bay, Ontario,
where they were processed for gold analysis by 50 gram fire assay with an atomic absorption finish. Samples from selected holes were sent
to AGAT Laboratories in Calgary, Alberta, for multi-element analysis (including silver) by inductively coupled plasma (ICP) method with
a four acid digest. AGAT Laboratories systems conform to requirements of ISO/IEC Standard 17025 guidelines and meets assay requirements
outlined for NI 43-101.
Qualified Person
Caroline Pienaar, P.Geo., Director of Exploration
for First Mining, is a "Qualified Person" for the purposes of NI 43-101 Standards of Disclosure for Mineral Projects and
has reviewed and approved the scientific and technical disclosure contained in this news release.
About First Mining Gold Corp.
First Mining is a gold developer advancing two of
the largest gold projects in Canada, the Springpole Gold Project in northwestern Ontario, where the federal Environmental Assessment for
the Springpole Project was approved in June 2026, , and the Duparquet Gold Project in Quebec, a PEA-stage development project located
on the Destor-Porcupine Fault Zone in the prolific Abitibi region. First Mining also owns a 20% project interest in the Pickle Crow Gold
Project in Ontario and a large equity interest in Seva Mining Corp.
First Mining was established in 2015 by Mr. Keith
Neumeyer, founder and CEO of First Majestic Silver Corp.
ON BEHALF OF FIRST MINING GOLD CORP.
Daniel W. Wilton
Chief Executive Officer and Director
Cautionary Note Regarding Forward-Looking Statements
This news release includes certain "forward-looking
information" and "forward-looking statements" (collectively "forward-looking statements") within the meaning
of applicable Canadian and United States securities legislation including the United States Private Securities Litigation Reform Act of
1995. These forward-looking statements are made as of the date of this news release. Forward-looking statements are frequently, but not
always, identified by words such as "expects", "anticipates", "believes", "plans", "projects",
"intends", "estimates", "envisages", "potential", "possible", "strategy",
"goals", "opportunities", "objectives", or variations thereof or stating that certain actions, events or
results "may", "could", "would", "might" or "will" be taken, occur or be achieved, or
the negative of any of these terms and similar expressions.
Forward-looking statements in this news release
relate to future events or future performance and reflect current estimates, predictions, expectations or beliefs regarding future events
and include but are not limited to, statements with respect to: (i) the potential for resource growth and future exploration
success at the Project; (ii) the commencement and success of any environmental baseline programs at the Project; (iii) the compilation
and interpretation of the drilling results at the Project; (iv) publication of a feasibility at the Duparquet Project; (v) feasibility
and permitting activities related to the Springpole Gold Project; and (vi) realizing the value of the Company's gold projects for the
Company's shareholders. All forward-looking statements are based on First Mining's or its consultants' current beliefs as well as various
assumptions made by them and information currently available to them. There can be no assurance that such statements will prove to be
accurate, and actual results and future events could differ materially from those anticipated in such statements. Forward-looking statements
reflect the beliefs, opinions and projections on the date the statements are made and are based upon a number of assumptions and estimates
that, while considered reasonable by the respective parties, are inherently subject to significant business, economic, competitive, political
and social uncertainties and contingencies. Such factors include, without limitation the Company's business, operations and financial
condition potentially being materially adversely affected by the outbreak of epidemics, pandemics or other health crises, and by reactions
by government and private actors to such outbreaks; risks to employee health and safety as a result of the outbreak of epidemics, pandemics
or other health crises, that may result in a slowdown or temporary suspension of operations at some or all of the Company's mineral properties
as well as its head office; fluctuations in the spot and forward price of gold, silver, base metals or certain other commodities;
fluctuations in the currency markets (such as the Canadian dollar versus the U.S. dollar); changes in national and local government, legislation,
taxation, controls, regulations and political or economic developments; risks and hazards associated with the business of mineral exploration,
development and mining (including environmental hazards, industrial accidents, unusual or unexpected formations, pressures, cave-ins and
flooding); the presence of laws and regulations that may impose restrictions on mining; employee relations; relationships with and claims
by local communities, indigenous populations and other stakeholders; availability and increasing costs associated with mining inputs and
labour; the speculative nature of mineral exploration and development; title to properties.; and the additional risks described in the
Company's Annual Information Form for the year ended December 31, 2025 filed with the Canadian securities regulatory authorities under
the Company's SEDAR+ profile at www.sedarplus.ca, and in the Company's Annual Report on Form 40-F filed with the SEC on EDGAR.
First Mining cautions that the foregoing list of
factors that may affect future results is not exhaustive. When relying on our forward-looking statements to make decisions with respect
to First Mining, investors and others should carefully consider the foregoing factors and other uncertainties and potential events. First
Mining does not undertake to update any forward-looking statement, whether written or oral, that may be made from time to time by the
Company or on our behalf, except as required by law.
Cautionary Note to United States Investors
The Company is a "foreign private issuer"
as defined in Rule 3b-4 under the United States Securities Exchange Act of 1934, as amended, and is eligible to rely upon the Canada-U.S.
Multi-Jurisdictional Disclosure System, and is therefore permitted to prepare the technical information contained herein in accordance
with the requirements of the securities laws in effect in Canada, which differ from the requirements of the securities laws currently
in effect in the United States. Accordingly, information concerning mineral deposits set forth herein may not be comparable with information
made public by companies that report in accordance with U.S. standards.
Technical disclosure contained in this news release
has not been prepared in accordance with the requirements of United States securities laws and uses terms that comply with reporting standards
in Canada with certain estimates prepared in accordance with NI 43-101.
NI 43-101 is a rule developed by the Canadian Securities
Administrators that establishes standards for all public disclosure an issuer makes of scientific and technical information concerning
the issuer's material mineral projects.
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For further information: For further information, please contact:
Toll Free: 1 844 306 8827 | Email: info@firstmininggold.com; Paul Morris | Director, Investor Relations | Email: paul@firstmininggold.com
CO: First Mining Gold Corp.
CNW 07:00e 10-SEP-26