First Mining Expands Newly Discovered Miroir Target with Drill Hole DUP25-064 Returning 3.23 g/t Au over 25.9 m
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NEWS RELEASE
First Mining Expands Newly Discovered Miroir Target with
Drill Hole DUP25-064 Returning 3.23 g/t Au over 25.9 m
• Near-surface drilling delivers multiple positive gold intercepts highlighted by DUP25-064, which
returned 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, extending mineralization to 100 m depth following previously delineated 100 m strike extension
• First Mining continues to test and advance the Miroir target mineralization controls with 20 holes and
~4,450 m completed to date
September 24, 2025 – Vancouver, Canada – First Mining Gold Corp. (“First Mining” or the “Company”)
(TSX: FF) (OTCQX: FFMGF) (FRANKFURT: FMG) is pleased to announce additional drilling results from the
2025 drilling program at its Duparquet Gold Project (“ Duparquet Project” or the “ Project”) located in the
Abitibi region of Quebec, Canada. The Company is actively drilling at the Duparquet Project through to the fall
and has completed ~16,000 m of drilling to date , with a continued focus on advancing potential resource
growth targets. Since the initial discovery (see January 2025 news release) , a total of 20 holes have been
drilled at Miroir, with assay results from some of these holes already disclosed . Assay results from the
remaining 13 holes drilled at Miroir as part of the 2025 program are pending. The Company will provide further
updates as results are received and interpreted. .
Drilling at the Miroir target, located 225 m north of the Central Duparquet - Valentre - Dumico (“CVD”) target,
continues to build strong continuity, returning multiple robust gold intercepts near surface. Assay results
from drill hole DUP25-064 returned 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 . D rill hole DUP25- 066, which is a 45 metre step-out to the e ast of DUP25- 064,
returned 1.37 g/t Au over 30.6 m, including 2.56 g/t Au over 4.0 m, and including 2.55 g/t Au over 6.6 m. These
latest drilling results further support the continuity of near -surface higher-grade mineralization and extends
the Miroir target to a vertical depth of 100 m below surface, where it remains open both up-dip toward surface
and at depth (Figure 1).
“The Miroir target continues to deliver new discoveries within the largely underexplored volcanic setting of
the Duparquet Project,” stated Dan Wilton, CEO of First Mining. “The strong grades and widths encountered
to date provide new and exciting opportunities in our review of development scenarios that can now include
near-surface, higher grade mineralization potential.”
The Miroir target is intersecting significant near-surface mineralization and this target represents an excellent
opportunity for expansion in this area (Figure 2). Interpreted as a folded structure from the 3D geological
model and airborne geophysics, the Miroir target is being drill tested to evaluate the near-surface and down-
plunge extent of mineralization. Notably, the Miroir host lithologies have a strong affinity towards brecciated
and altered mafic volcanic host lithologies, occurring within a volcanic sequence in close proximity to syenite
intrusive units. Recent exploration success at Miroir continues to highlight this area together with the CVD
and Aiguille targets as an emerging cluster of potential resource growth centres with synergies for future
mining development.
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The latest reported assays represent approximately 600 m of drilling from a total of ~4,450 metres across 20
drill holes. These holes were focused on advancing the understanding of mineralization controls at the Miroir
target. Assay highlights are provided in Table 1, with the full list of assay results in Table 2 and drill collar
details in Table 3.
Figure 1: Miroir Long Section (A-A’ reference on Figure 3), highlighting recent drilling as well as the open-ended potential of the Miroir
interpreted fold structure. The long section is looking north.
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Further drill testing ongoing at the Miroir target where assays are pending is shown in Figure 1. As
results are returned and reviewed, First Mining will continue to interpret and evolve the geological
understanding of the area for further drill advancement.
Table 1: Significant 2025 Drill Intercepts from the Miroir Target
Hole ID From
(m) To (m) Length (m) Grade (Au g/t) Target
DUP25-064 32.5 37.1 4.6 4.64 Miroir
DUP25-064 inc. 34.0 36.4 2.4 6.30 Miroir
DUP25-064 122.35 127.2 4.85 1.72 Miroir
DUP25-064 inc. 123.0 124.0 1.0 6.05 Miroir
DUP25-064 159.1 185.0 25.9 3.23 Miroir
DUP25-064 inc. 164.0 166.0 2.0 11.20 Miroir
DUP25-064 and inc. 176.6 178.0 1.4 10.16 Miroir
DUP25-064 198.6 206.0 7.4 4.15 Miroir
DUP25-064 inc. 199.8 202.8 3.0 8.72 Miroir
DUP25-066 18.0 40.0 22.0 0.64 Miroir
DUP25-066 60.0 63.0 3.0 2.43 Miroir
DUP25-066 157.0 187.6 30.6 1.37 Miroir
DUP25-066 inc. 157.0 161.0 4.0 2.56 Miroir
DUP25-066 and inc. 179.0 185.6 6.6 2.55 Miroir
DUP25-067 78.0 82.0 4.0 2.58 Miroir
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Figure 2: Plan view map, highlighting the Miroir target area and multiple significant near-surface assay results, and showing the 2nd
vertical derivative magnetics geophysical product and newly interpreted fold at the Miroir area.
Duparquet 2025 Exploration Program Updates
Exploration activities at the Duparquet Project continue to advance, with more than 16,000 m drilled to date
in 2025. Drilling remains focused o n key resource expansion targets including CVD, Miroir, Aiguille, North
Zone, South Zone, and the Minuit Zone, where programs are aimed at building on the Project’s strong growth
potential (Figure 3 ). In parallel, regional field programs are progressing to refine and advance additional
targets toward future drill readiness.
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Figure 3: Plan view map of Duparquet geology and mineral resource with main targets around the project core area, showing A-A’ long
section line on Figure 1
Additional Details on the Miroir Target
The most recent 2025 drilling at the Miroir target focused on further delineating the extent of near -surface
mineralization discovered in 2024 with drill hole DUP24- 048 returning 3.12 g/t Au over 19.35 m (see news
release dated January 20, 2025). Earlier drilling this year, including drill hole DUP25- 052, returned a further
intercept along strike of 2.77 g/t Au over 11.1 m, including 4.36 g/t Au over 6.5 m (see news release dated May
28, 2025), demonstrating encouraging grades and widths within this shallow target. The most recent drilling
continues to confirm and expand the Miroir target, extending mineralization to a vertical depth of 100 m below
surface and highlighting multiple near-surface gold zones (Figures 4 and 5).
The interpreted geophysical fold target has now been expanded to a strike length of 140 m, reinforcing the
shallow, high-potential nature of the target and its ongoing growth potential. Notable results from the most
recent drilling include drill hole DUP25-064, which returned 4.64 g/t Au over 4.6 m, including 6.3 g/t Au over
2.4 m, as well as 3. 23 g/t Au over 25.9 m, including 11.2 g/t Au over 2.0 m and 10.16 g/t Au over 1.4 m, and
4.15 g/t Au over 7.4 m, including 8.72 g/t Au over 3.0 m. Drill hole DUP25-066 returned 0.64 g/t Au over 22.0
m and 1.37 g/t Au over 30.6 m, including 2.56 g/t Au over 4.0 m, while DUP25-067 returned 2.58 g/t Au over
4.0 m. These results continue to demonstrate the multiple, high- quality gold zones within the Miroir target
and reinforce its potential for further expansion.
Mineralization at the target area is typically associated with syenite-basalt contacts. Mineralization in the
most recent drill holes is hosted within brecciated silica-altered syenite and basalt, with up to 10% very fine-
grained disseminated pyrite mineralization, and is associated with smoky dark quartz veinlets. The
mineralized intercepts are spatially correlated with D2 deformation zones and coincident with a geophysical
inferred folded basalt-syenite contact that is striking northeast to southwest and plunging towards the east.
Further validation and refinement is p lanned to test the plunge dip directions and stratigraphic controls on
mineralization in this area.
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Figure 4: Plan view and cross section of DUP25-064 highlighting multiple mineralized intercepts at the Miroir target.
Figure 51: Plan view and cross section of DUP25-066 highlighting significant intercepts downhole.
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Table 2: Latest Assay Results from 2025 Drill Program
Hole ID From (m) To (m) Length (m) Grade (Au g/t) Target
DUP25-064 32.5 37.1 4.6 4.64
Miroir
DUP25-064 inc. 34.0 36.4 2.4 6.30
DUP25-064 60.75 62.7 1.95 0.76
DUP25-064 102.65 104.0 1.35 0.85
DUP25-064 106.35 106.9 0.55 0.60
DUP25-064 122.35 127.2 4.85 1.72
DUP25-064 inc. 123.0 124.0 1.0 6.05
DUP25-064 153.3 154.3 1.0 0.57
DUP25-064 159.1 185.0 25.9 3.23
DUP25-064 inc. 164.0 166.0 2.0 11.20
DUP25-064 and inc. 176.6 178.0 1.4 10.16
DUP25-064 193.5 194.4 0.9 0.59
DUP25-064 198.6 206.0 7.4 4.15
DUP25-064 inc. 199.8 202.8 3.0 8.72
DUP25-064 inc. 199.8 200.8 1.0 14.80
DUP25-066 10.0 11.0 1.0 0.46
Miroir
DUP25-066 18.0 40.0 22.0 0.64
DUP25-066 48.0 48.7 0.7 0.81
DUP25-066 60.0 63.0 3.0 2.43
DUP25-066 79.0 81.0 2.0 0.68
DUP25-066 84.2 87.0 2.8 0.72
DUP25-066 110.6 111.25 0.65 0.41
DUP25-066 128.0 129.0 1.0 0.48
DUP25-066 131.5 136.5 5.0 0.56
DUP25-066 141.0 141.64 0.64 0.69
DUP25-066 157.0 187.6 30.6 1.37
DUP25-066 inc. 157.0 161.0 4.0 2.56
DUP25-066 and inc. 179.0 185.6 6.6 2.55
DUP25-066 191.2 192.0 0.8 3.02
DUP25-067 49.0 53.9 4.9 0.64
Miroir DUP25-067 56.65 58.0 1.35 0.51
DUP25-067 78.0 82.0 4.0 2.58
*Reported intervals are drilled core lengths (true widths are estimated at 75-85% of the core length interval; assay values
are uncut)
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Table 3: 2025 Drill Hole Locations, Miroir Target
Hole ID Azimuth (°) Dip (°) Length (m) Easting Northing
DUP25-064 340 -45 207 633606 5374002
DUP25-066* 330 -45 294 633646 5374023
DUP25-067 325 -50 201 633682 5374084
Note: Collar coordinates in UTM NAD 83 z17
*Hole DUP25-066 was extended extra further 102 m due to favourable mineralization intersected near the original end
of hole; assays for extended portion are still pending
About the Duparquet Gold Project
The Duparquet Project is geologically situated in the southern part of the Abitibi Greenstone Belt and is
geographically located approximately 50 km north 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 3.4 4 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 Assessment 1
(“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 2025 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. S amples 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.