First Mining Gold Announces Drilling Update and new Carey Discovery on its Pickle Crow Gold Project

Auteco Minerals Makes Discovery of Near Surface, High Grade Mineralization
Highlighting Open Pit Potential

VANCOUVER, July 27, 2021 - First Mining Gold Corp. ("First Mining" or the "Company") (TSX: FF) (OTCQX: FFMGF) (FRANKFURT: FMG) is pleased to announce the commencement of a second phase, 50,000 m drill program at its Pickle Crow gold project in northwestern Ontario, Canada, to follow on from the strong results obtained in the initial 45,000 m program completed by First Mining's Joint Venture partner Auteco Minerals Ltd ("Auteco") in 2020 and 2021. Further drilling is being done on the new Carey discovery, which is the first in a series of shallow exploration targets being tested by Auteco that highlight the potential for open pit mining in addition to what was historically a narrow-vein underground operation at Pickle Crow. Follow up drilling is underway to determine the continuity of mineralization at Carey between historical drillholes to the north and south of the initial intersections.

To date, 14 diamond drill holes totalling 5,622 m of drilling have been completed from the new program, following on from the initial 45,522 m from 166 diamond holes which were completed in the first program. Of these new holes, assay results have been partially received for five holes, and assays are yet to be received for a further nine holes. There are currently four drill rigs on site. Auteco's dual strategy of driving near-mine resource growth combined with early-stage exploration targeting will continue to be the focus of the drilling program.

All drilling completed between September 2020 and June 2021 has been conducted outside of the current resource area.

Mapping, outcrop sampling and the acquisition of detail ground magnetics is also in progress on the regional tenure outside of the current resource area. Assay results returned from rock chip samples of outcropping veins at the Springer Prospect have returned results up to 145.7 g/t gold.

In anticipation of continued success, Auteco has engaged leading environmental consulting firm Wood PLC to coordinate and conduct activities relating to Advanced Exploration permitting with the Ontario Ministry of Energy, Northern Development and Mines. Additionally, Auteco has commenced preliminary discussions with a number of engineering firms to conduct assessments of processing and mining infrastructure inherited with the Pickle Crow project.

"We are excited about the highly successful exploration program being completed by our joint venture partner Auteco at our Pickle Crow Project." stated Dan Wilton, CEO of First Mining. "The Carey discovery is only one of several shallow exploration targets being tested by Auteco, which may indicate potential for an open-pittable resource at the Project in addition to underground targets. Furthermore, the recent drilling has successfully extended the known high-grade mineralization in the Shaft 3 area. We are impressed with the commitment and technical expertise of our joint venture partner Auteco to undertake and complete the first phase of their exploration program in such an aggressive timeline and with such impressive results, and we look forward to the assay results from the additional 50,000 metres of drilling which has just commenced."

EXPLORATION HIGHLIGHTS

• Initial 45,000 metre drill program complete and additional 50,000 metre program now commenced
• New, shallow high-grade gold discovery ('Carey Discovery') with drill results including:
• • 5.8 m @ 16.2 g/t gold from 112.8 m in AUDD0158 (New Structural Zone) including 2.2 m @ 39.4 g/t
  • 14.9 m @ 2.2 g/t gold from 28.7 m in AUDD0137 (New Structure)
  • 16.5 m @ 2.3 g/t gold from 160.6 m in AUDD0141 (New Structure)
  • 6.5 m @ 4.6 g/t gold from 86.5 m in AUDD0138 (New Structure)
  • 3.3 m @ 4.7 g/t gold from 54.3 m in AUDD0134 (New Structure)
• Extension of known, high-grade gold mineralization in the Shaft 3 and Shaft 1 areas with drill results including:
• • 4.9 m @ 7.5 g/t gold from 483.2 m in hole AUDD0152 (New Structure - Shaft 3)
  • 3.3 m @ 8.0 g/t gold from 836.4 m in hole AUDD0166 (80 m Extension of Structure - Shaft 3)
  • 6.5 m @ 6.6 g/t gold from 838.1 m in AUDD0166W1 (New Structure - Shaft 3) including 1.8 m @ 21.2 g/t
  • 4.9 m @ 4.7 g/t gold from 514.1 m in AUDD0178 including 2.1 m @ 10.4 g/t (New Structure - Shaft 3)
  • 1.0 m @ 14.1 g/t gold from 432.0 m in AUDD0179 (New Structure - Shaft 3)
  • 1.3 m @ 21.4 g/t gold from 82.1 m in hole AUDD0128 (80 m Extension of Structure - Shaft 3)
  • 0.6 m @ 42.9 g/t gold from 320.0 m in hole AUDD0128 (80 m Extension of Structure - Shaft 3)
  • 4.6 m @ 7.5 g/t gold from 183.5 m in hole AUDD0064 (80 m Extension of Structure - Shaft 1)
• Regional mapping and reconnaissance sampling has yielded significant results, with outcropping veins at the Springer target returning rock chip results including:
• • 145.7 g/t gold, 6.2 g/t gold, 5.7 g/t gold and 4.3 g/t gold

Carey Discovery

The Carey prospect was a conceptual target zone focused on an area of structural disruption adjacent to the contacts between multi-generational porphyritic intrusions and the host rock, which includes mafic volcanics and banded iron formation (BIF). Drilling completed since April 2021 has confirmed several bulk tonnage targets centred around high grade gold veins proximal to the Albany Porphyry and later stage quartz-feldspar porphyries (Figure 3). Intersections returned from first pass target testing include:

• 5.8 m @ 16.2 g/t gold from 112.8 m in hole AUDD0158 (New Structure) including 2.2 m @ 39.4 g/t
• 14.9 m @ 2.2 g/t gold from 28.7 m in hole AUDD0137 (New Structure)
• 16.5 m @ 2.3 g/t gold from 160.6 m in hole AUDD0141 (New Structure)
• 6.5 m @ 4.6 g/t gold from 86.5 m in AUDD0138 (New Structure)
• 3.3 m @ 4.7 g/t gold from 54.3 m in AUDD0134 (New Structure)

Mineralization is observed within quartz-ankerite-pyrite veins and disseminated sulphides in shearing developed both to the contacts of the Albany Porphyry and Riedel shears developed within the intrusion. The intrusion has been crosscut by intermediate porphyry dykes which, due to rheological contrast, preferentially undergo brittle-ductile deformation. The dykes are intensely sericite-ankerite-pyrite altered, and locally contain discrete quartz-ankerite-pyrite veins. High-grade gold zones are associated with the sulphides.

Drill results from the greater Carey-Albany area, including the initial results from the Carey discovery, are shown in Figure 1. Mineralization remains open in all directions on targeted structures, and work will now focus on defining continuity within the mineralized envelopes. Follow up drilling at the Carey discovery is now in progress.

Figure 1: Map of the greater Carey-Albany area, showing the location of the Carey prospect proximal to the Albany Porphyry

Greater Carey-Albany Area

Historical drilling in the greater Carey-Albany area also demonstrates the presence of broad, shallow mineralization, and further exploration drilling is planned to confirm historical results and test the open pit potential of this area.

Near Mine Extension and Exploration Drilling

Further extension and exploration drilling has been completed in both the Shaft 3 and Shaft 1 areas. The latest drilling has continued to focus on the Shaft 3 area, where step-out holes have returned intersections that demonstrate the continuation of known veins beyond the current known extents.

The location of drilling in the Shaft 1 and Shaft 3 areas is shown in Figure 2.

Figure 2: Plan location map of recent drilling in the Shaft 3 and Shaft 1 areas of the Pickle Crow deposit

Shaft 3

Exploration drilling in the Shaft 3 area intersected a previously undiscovered shear vein in hole AUDD0152 within the Pickle Crow assemblage. This intersection includes multiple occurrences of visible gold and was located ~250 m northwest of the nearest drillhole (Figure 2). The assayed intersection for this hole was:

• 4.9 m @ 7.5 g/t gold from 483.2 m in hole AUDD0152

Further drilling completed since June 2021 has continued to test the area to the north-west of Shaft 3, and drilling proximal to the newly discovered vein structure in AUDD0152 has continued to intersect veins that indicate continuity.

Significant intersections returned from the latest drilling north-west of Shaft 3 include:

• 3.3 m @ 8.0 g/t gold from 836.4 m in AUDD0166 (New Structure)
• 6.5 m @ 6.6 g/t gold from 838.1 m in AUDD0166W1 (New Structure) including 1.8 m @ 21.2 g/t
• 4.9 m @ 4.7 g/t gold from 514.1 m in AUDD0178 including 2.1 m @ 10.4 g/t (New Structure)
• 1.0 m @ 14.1 g/t gold from 432.0 m in AUDD0179 (New Structure)

Other significant results in the Shaft 3 area are shown on Figure 2.

Regional Exploration

Regional field reconnaissance and mapping in areas outside of the current resource area is in progress, supported by ongoing ground magnetic surveys that have been successfully utilized to identify geophysical signatures associated with high grade, quartz-scheelite-tourmaline-gold bearing structures in the Pickle Crow area.

The magnetic survey highlights displacement and demagnetization of the magnetic Banded Iron Formation coincident with mineralized cross structures (Figure 3). Analogous geophysical target signatures have now been identified both to the southwest of Vein 5, the Crowshore area and at the Springer Shaft.

At the Springer Shaft, displacements in the Banded Iron Formation (BIF) observed in the Ground Magnetics are coincident with high grade historical drill intercepts including:

• 1.7 m @ 44.41 g/t gold from 15.1 m in hole CPSH-88-01
• 4.6 m @ 13.13 g/t gold from 27.1 m in hole CP-88-092
• 0.8 m @ 86.98 g/t gold from 16.2 m in CPSH-88-03
• 0.8 m @ 50.32 g/t gold from 10.5 m in CPSH-88-02
• 0.8 m @ 7.3 g/t gold from 26.5 m in CP-88-072

These results are supported by recent mapping which has identified three mineralized shear veins in the proximity of the Springer Shaft (Figure 3) with rock chip results including:

• 145.7 g/t gold (rock chip sample of outcropping surface vein)
• 6.2 g/t gold (rock chip sample of outcropping surface vein)
• 5.7 g/t gold (rock chip sample of outcropping surface vein)
• 4.3 g/t gold (rock chip sample of outcropping surface vein)

Figure 3: High quality ground magnetic survey data completed in the Shaft 1 (top left) and Springer (right) areas. Structural displacement of the BIF units is observed, in addition to demagnetization at structural intersections.

Please refer to Table 1 below for a full list of rock chip sampling completed in this area.

The newly identified target zones represent compelling targets that will undergo preliminary drill testing in coming months.

A complete list of the 2020 and 2021 drill results to date, including hole details, can be viewed at: Results.

Drill Hole Locations

About Pickle Crow

The Pickle Crow Gold Deposit is a high-grade, shear-hosted, mesothermal Archean lode gold deposit. The deposit occurs primarily within mafic volcanics and banded iron formation (BIF) units in the Pickle Crow assemblage of the Pickle Lake Greenstone belt located in the Uchi Lake Sub-province of the Superior Craton of the Canadian Shield.

Mineralization is focused around steeply north-west dipping, regional scale shear zones. Multiple mineralization styles have been identified on the property, including Quartz-Gold-Tungsten (+/-Tourmaline) Shear Veins which are the focus of the current exploration, and banded iron formation mineralization (BIF-style), which comprises structurally-controlled, sheeted vein arrays hosted within the BIF.

Pickle Crow is one of Canada's highest-grade historical gold mines. It operated from 1935 until 1966, during which time it reportedly produced almost 1.5 million ounces of gold at an average grade of 16.14 g/t. The property consists of ~190 km² (19,000 hectares) of tenure covering a major gold province. Auteco recently increased its landholding near the Project by staking an additional 130 km² (13,000 ha) of land contiguous to Pickle Crow, thereby increasing the combined property's land package to over 320 km² (32,000 ha) (see news release dated February 18^th, 2020). First Mining acquired the Project in November 2015 through its acquisition of PC Gold Inc.

Auteco's development focus is on returning to first principles, completing a new geological review and applying modern exploration technologies in their advancement of the Project. Auteco has a strong focus on discovering and developing new project scale, high-grade, near surface gold resources.

QA/QC Procedures

The QA/QC program for the Auteco drill program consists of the submission of duplicate samples and the insertion of Certified Reference Materials (CRMs), including low, medium and high-grade standards and coarse blanks, at regular intervals in the sample stream. One set of the four QA/QC sample types were inserted every 25 samples, consisting of 1 coarse duplicate, 1 quarter-split field duplicate, 1 CRM (altering between low, medium and high standards) and 1 blank. AGAT laboratories also undertakes its own internal QAQC program to ensure proper sample preparation and equipment calibration.

Qualified Person

Hazel Mullin, P.Geo., Director, Data Management and Technical Services of First Mining, is a "Qualified Person" for the purposes of National Instrument 43-101 Standards of Disclosure for Mineral Projects, and she has reviewed and approved the scientific and technical disclosure contained in this news release.

About First Mining Gold Corp.

First Mining is a Canadian gold developer focused on the development and permitting of the Springpole Gold Project in northwestern Ontario. Springpole is one of the largest undeveloped gold projects in Canada. The results of a positive Pre-Feasibility Study for the Springpole Gold Project were announced by First Mining in January 2021, and permitting activities are on-going with submission of an Environmental Impact Statement ("EIS") for the project targeted for 2021. The Company also holds a large equity position in Treasury Metals Inc. who are advancing the Goliath-Gold Complex towards construction. First Mining's portfolio of gold projects in eastern Canada also includes the Pickle Crow (being advanced in partnership with Auteco Minerals Ltd.), Hope Brook (being advanced in partnership with Big Ridge Gold Corp.), Cameron, Duparquet, Duquesne, and Pitt gold projects.

First Mining was established in 2015 by Mr. Keith Neumeyer, founding President 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) timing for Auteco to incur additional expenditures on the Pickle Crow project; (ii) timing of the release of the remaining assay results from the first phase of drilling as well as assay results for the next 50,000 m drill program; (iii) timing and outcome of Wood PLC commencing activities related to advanced exploration; (iv) timing and outcome of the selection of an engineering firm to conduct assessments of processing and mining infrastructure inherited with the Pickle Crow Project; (V) the potential for an open-pittable resource in addition to an underground project and (vi) submission of an EIS for the Springpole Gold Project. 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, such as COVID-19, 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, such as COVID-19, 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, 2020 filed with the Canadian securities regulatory authorities under the Company's SEDAR profile at www.sedar.com, 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.

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