First Mining Further Defines Expansion Opportunity and Adds Second Drill Rig at the Duparquet Gold Project

• Drilling at Valentre target intersects 3.98 g/t Au over 8.7m and 1.82 g/t Au over 14.35m

• Confirms continuity of mineralization between Central Duparquet pit and Dumico pit and demonstrates resource expansion opportunity

VANCOUVER, BC / ACCESSWIRE / August 28, 2024 / First Mining Gold Corp. ("First Mining" or the "Company") (TSX:FF)(OTCQX:FFMGF)(FRA:FMG) is pleased to announce new drilling results from the 2024 Phase 3 diamond drilling program at its Duparquet Gold Project ("Duparquet Project" or the "Project") located in Quebec, Canada. These new drill results further define resource expansion opportunities at an under-tested area termed the Valentre target ("Valentre"), where follow-up drilling is now taking place. Drilling continues on priority targets at the Project where a second drill rig is planned to mobilize in September, allowing First Mining to test regional exploration targets while concurrently advancing recent exploration discoveries at the North Zone (see news release dated June 18, 2024), Buzz (see news release dated February 22, 2024) and Valentre.

Recent drilling at Valentre has returned positive drill intercepts from an area of 175 m of strike length that is under tested and envisioned to establish mineralization continuity within a key area of the project. Highlights of the recent drilling include 3.98 g/t Au over 8.70 m (DUP24-026), and 1.82 g/t Au over 14.35 m (DUP24-027), demonstrating both encouraging grades and widths within an area of potential resource growth and further exploration opportunities.

"We continue to execute on an exploration plan that clearly demonstrates the resource growth potential at Duparquet, already one of the largest undeveloped gold projects in Canada" stated Dan Wilton, CEO of First Mining. "The success at Valentre is a tangible result of the hard work our exploration team has put into understanding the geology at Duparquet over the past two years and gives First Mining confidence in continued exploration success at this robust project."

The Phase 3 drill program commenced in April with a total of approximately 5,700 m completed to date. This program aims to test priority targets focusing on multiple potential resource expansion zones across the Duparquet Project. The initial results returned from the Phase 3 campaign are from select holes at Valentre, which tests an area between the Central Duparquet and Dumico resource pit shells which was previously not drilled due to a historical property boundary. Further Phase 3 drilling has continued at the Buzz Zone and the North Zone Expansion target areas, with additional results expected for future release. Further drill testing is ongoing, focusing on other brownfields opportunities with the aim of identifying higher-grade zones and targeted resource expansion opportunities.

A plan map of the Valentre and Central Duparquet drill holes is presented in Figure 1, and corresponding assay highlights are presented in Table 1, with full assay results listed in Table 2 and drill hole locations in Table 3.

Table 1: Selected Significant Drill Intercepts, 2024 Phase 3 Drill Program - Valentre and Central Duparquet Targets

_{*Reported intervals are drilled core lengths (true widths are estimated at 75-85% of the core length interval, assay values are uncut)}

_{Figure 1: Plan view of select drill holes from the Phase 3 program at the Valentre Target area.}

Additional Details on Valentre Drilling

The Valentre drilling strategy is focused on targeting resource growth opportunities towards the eastern side of the main resource where an opportunity for strike extension of the mineralization was identified. This mineralization extension opportunity spans 175 m on strike between two established centres of mineral resource wireframes (Central Duparquet and Dumico). During the 2023 drilling program, an initial single hole (DUP23-006) was drilled to test this opportunity, resulting in the successful identification of six intervals of significant gold mineralization including 1.71 g/t Au over 8.9m (refer to news release dated January 9, 2024).

The initial 2024 Valentre follow-up drilling campaign, comprising of three holes (DUP24-025, DUP24-026 and DUP24-027), has now confirmed continuity in the mineralization along strike and at depth. Mineralization in all three holes is associated with strong silica-altered syenite with dark grey quartz veining and up to 5% fine-grained disseminated pyrite throughout the unit as illustrated in Figures 2, 3 and 4. Higher-grade zones are consistent along interpreted D2 structures, which are characterized by strong shearing and/or brecciation observed in the core.

_{Figure 2: Valentre Target - DUP24-025 is a hole targeting the potential mineralization continuity between Central Duparquet and Dumico. Significant intercepts are highlighted downhole, with higher-grade zones identified along altered mineralized syenite units. The cross section is looking west.}

_{Figure 3: Valentre Target - DUP24-026 is a second hole targeting the potential mineralization continuity between Central Duparquet and Dumico. Significant intercepts are highlighted downhole, with higher-grade zones identified along altered mineralized syenite units. This drill hole is also a test of mineralization continuity up-dip of previously drilled hole DUP23-006.The cross section is looking west.}

_{Figure 4: Central Duparquet Target - DUP24-027 is a hole targeting the potential mineralization continuity between Central Duparquet and Valentre as well as at depth. Significant intercepts are highlighted downhole, with higher-grade zones identified along altered mineralized syenite units. The cross section is looking west.}

An additional 12 holes (Figure 5) are planned for Valentre in the 2024 drilling campaign, which aims to further test the strike extension as well as depth expansion opportunities alongside advancing the characterization of the mineralization in support of delineating higher-grade trends. This drilling will further provide support in new wireframe updates. Valentre has returned significant upside and value to the Duparquet Project and is a priority area for exploration optimization and potential extension of the current open pit and underground mineral resource. The recent drill results continue to support the area as a highly prospective target zone for the Project, with potential to unlock meaningful upside along strike and at depth (Figure 5).

^{Figure 5: Representative long section through the Central Duparquet, Valentre, and Dumico Targets, highlighting the multiple significant intercepts returned in 2023 and in the 2024 Phase 3 program as well as the upcoming drill hole targets aimed at unlocking exploration opportunities}

Duparquet 2024 Exploration Program

Exploration activities continue to advance at the Duparquet Project through 2024, with ongoing drilling and regional field work programs. Exploration efforts are advancing with the follow up programs established through a prospectivity and target pipeline, which has recently been further augmented by the completion of an airborne geophysical magnetic and VLF-EM surveys as well as property wide expansion of the 3D geological and target model. The remainder of the 2024 program will advance with two drill rigs on the project and the close out of the summer field campaigns developed in support of the Company's integrated geoscience exploration strategy.

Table 2: Phase 3 Valentre and Central Duparquet Drilling - Significant Assays

_{*Reported intervals are drilled core lengths (true widths are estimated at 75-85% of the core length interval; assay values are uncut)}

Table 3: Phase 3 Drill Hole Locations, Valentre and Central Duparquet Targets