#1FIRST MINING GOLD Corporate Presentation APRIL 2024 TSX: FF OTCQX: FFMGF FRANKFURT: FMG www.firstmininggold.com#2FORWARD LOOKING STATEMENTS G FIRST MINING GOLD This presentation 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 presentation. 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", "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 presentation 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) First Mining Gold Corp.'s ("First Mining" or the "Company") business strategies and objectives, including plans, opportunities, expectations and intentions; (ii) the timing and amount of planned and future exploration and expenditures and the possible results of such exploration; (iii) the estimated amount and grade of mineral resources and mineral reserves at the Company's projects; (iv) the expected benefits of the transaction with First Majestic Silver Corp. and the timing of any payments to the Company in connection with the transaction; (v) the expected benefits of the transaction with Treasury Metals Inc. ("Treasury Metals"); (vi) the future plans and objectives relating to the Goliath Gold Complex including any work plans of Treasury Metals; (vii) timing for the receipt of any milestone- based payments in the transaction with Treasury Metals; (viii) timing for the receipt of any cash and/or share payments from FireFly Metals Ltd ("FireFly") in respect of the various earn-in stages required to complete their earn-in of up to an 80% interest in the Company's Pickle Crow gold project; (ix) timing for the receipt of any cash and/or share payments from Big Ridge Gold Corp. ("Big Ridge") in respect of the various earn-in stages required to complete their earn-in of up to an 80% interest in the Company's Hope Brook gold project; (x) non-GAAP valuations regarding any future cash and/or share payments that the Company expects to receive from Treasury Metals, FireFly or Big Ridge; (xii) the Springpole PFS representing a viable development option for the Company's Springpole gold project; (xiii) construction of a mine at the Springpole project and related actions, including dewatering activities; (xiv) estimates of the capital costs of constructing mine facilities and bringing a mine into production, of sustaining capital and the duration of financing payback periods related to the Springpole project; (xv) the estimated amount of future production, both produced and metal recovered, from the Springpole project; (xvi) life of mine estimates and estimates of operating costs, all-in sustaining costs and total costs, net cash flow, net present value and economic returns from an operating mine constructed at the Springpole project; (xvii) the advancement of permitting activities and applications related to the Springpole project; (xviii) the timing for submitting an Environmental Impact Statement in respect of the Springpole project and all dates that relate to the permitting timeline for the project; (xix) the results of the Preliminary Economic Assessment ("PEA") completed for the Duparquet Gold Project ("Duparquet"), including the economic potential and merits thereof and the PEA is preliminary in nature, that it includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that the PEA will be realized; (xx) the estimated capital and operating costs, production, cash flow and life of mine estimates and economic returns from Duparquet; (xxi) the estimated amount and grade of mineral resources at Duparquet; and (xxii) current and future drilling strategies and programs at Duparquet. 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. By their very nature, forward-looking statements involve inherent risks and uncertainties, both general and specific, and risks exist that estimates, forecasts, projections and other forward-looking statements will not be achieved or that assumptions do not reflect future experience. We caution readers not to place undue reliance on these forward-looking statements as a number of important factors could cause the actual outcomes to differ materially from the beliefs, plans, objectives, expectations, anticipations, estimates assumptions and intentions expressed in such forward-looking statements. These risk factors may be generally stated as the risk that the assumptions and estimates expressed above do not occur as forecast, but specifically include, without limitation: (i) the risk that the Company's business, operations and financial condition may be 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; (ii) risks to the health and safety of the Company's employees and consultants 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; (iii) the risk that the Company will not be successful in completing additional acquisitions; (iv) risks relating to the results of exploration activities; (v) risks relating to the ability of the Company to enter into joint venture, earn-in, royalty or streaming structure agreements, or to dispose of its mineral properties; (vi) developments in world metals markets; (vii) risks relating to fluctuations in the spot and forward price of gold, silver, base metals or certain other commodities; (viii) risks relating to fluctuations in the Canadian dollar relative to the US dollar; (ix) the speculative nature of mineral exploration and development; (x) 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); (xi) availability of necessary financing and any increases in financing costs or adverse changes to the terms of available financing, if any; (xii) changes in regulations applying to the development, operation, and closure of mining operations from what currently exists; (xiii) the effects of competition in the markets in which First Mining operates; (xiv) operational and infrastructure risks; (xv) risks relating to variations in the mineral content within the material identified as mineral resources from that predicted; (xvi) risks relating to the failure to distribute a significant portion of the equity consideration from the transaction with Treasury Metals to the Company's shareholders; (xvii) increases in estimated capital and operating costs or unanticipated costs with respect to any of the Company's mineral projects (xviii) difficulties attracting the necessary work force; (xix) risks relating to receipt of permits and regulatory approvals; (xx) delays in stakeholder negotiations (including negotiations with affected local and Indigenous communities of interest around our material projects); (xxi) tax rates or royalties being greater than assumed; (xxii) changes in development or mining plans due to changes in logistical, technical or other factors; (xxiii) changes in project parameters as plans continue to be refined (xxiv) management's discretion to alter the Company's short and long- term business plans; (xxv) the additional risks described in First Mining's Annual Information Form for the year ended December 31, 2022 filed with the Canadian securities regulatory authorities under the Company's SEDAR+ profile at www.sedarplus.ca, and in First Mining'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. 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 ("NI 43-101"), and she has reviewed and approved the scientific and technical disclosure contained in this presentation. Louis Martin P.Geo, (OGQ 0364) of First Mining, is a "qualified person" for the purposes of NI 43-101, and he has reviewed and approved the scientific and technical disclosure contained in this presentation. Note: all information presented in Canadian dollars unless otherwise noted; as at April 12, 2024. TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com 1#3WHY FIRST MINING Advancing two of the 10 largest undeveloped gold projects in Canada G Springpole Gold Project large, robust, feasibility stage, advanced permitting Positive PEA at the Duparquet Gold Project in the heart of the Abitibi gold belt in Quebec Portfolio of other assets provides optionality and financing flexibility as demonstrated through recent non-core asset sales Experienced exploration, development and environmental team in place to unlock value FIRST MINING'S ADVANCED STAGE GOLD PROJECTS DELIVER UNPARALLELED LEVERAGE TO A RISING GOLD PRICE TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com FIRST MINING GOLD SPRINGPOLE DUPARQUET | 2#4OVERVIEW OF FIRST MINING ASSETS Flagship Assets Springpole Gold Project in Ontario, Canada + Duparquet Gold Project in Quebec, Canada SPRINGPOLE GOLD PROJECT Ontario, Canada PFS Released in Q1 2021 Advancing through Feasibility and Permitting FireFly METALS PICKLE CROW (30%) Ontario, Canada Joint Venture with FireFly Metals FireFly Option to Earn-In to 80% Other Assets Pickle Crow (30%): JV with FireFly Metals (ASX: FFM) Hope Brook (20%): JV with Big Ridge Gold (TSXV:BRAU) Cameron (100%): Wholly owned and operated by First Mining Treasury Metals (TSX:TML): Largest shareholder (11% ownership) TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Flagship Assets Other Assets CAMERON GOLD PROJECT Ontario, Canada 100% Owned by First Mining ONTARIO G FIRST MINING GOLD Canada QUÉBEC BIG RIDGE -GOLD CORP HOPE BROOK (20%) Newfoundland, Canada Joint Venture with Big Ridge TREASURY -METALS Inc. GOLIATH GOLD COMPLEX Ontario, Canada Largest Shareholder in Treasury Metals Future Milestone Payments DUPARQUET GOLD PROJECT Quebec, Canada PEA released in Q3 2023 Advancing exploration and project development | 3#5CORPORATE OVERVIEW SUMMARY DETAILS Shares Issued & Outstanding 916 Million CURRENT OWNERSHIP G FIRST MINING GOLD Options and RSUs Outstanding 88 Million MANAGEMENT & DIRECTORS Warrants Outstanding 85 Million 4.4% 1.7% Fully Diluted Shares Outstanding 1,089 Million 82% RETAIL fm FIRST MAJESTIC ALVLE CORP FIRST MINING GOLD Market Capitalization - Basic $151 Million 12% INSTITUTIONAL Cash-on-Hand ~$10 Million Debt Nil Marketable Securities (1) $5 Million Enterprise Value - Basic $136 Million ANALYST COVERAGE Future Cash and Share Payments (2) $17 Million Implied Value of JV Interests (3) $23 Million CANTOR Bitzgerald CORMARK Matthew O'Keefe Richard Gray Average Daily Volume Canada: 2,200,000 (Past 3 Months) U.S.: 660,000 Note: Market data as at April 12, 2024 SECURITIES INC. × HCW H.C.WAINWRIGHT&CO. Heiko Ihle LAURENTIAN BANK SECURITIES Jacques Wortman (1) Marketable securities includes shares held for sale, including shares of Treasury Metals (2) Future cash and share payments: US$5 million from First Majestic in cash and shares for sale of 50% silver stream on Springpole; C$3 million cash payment from FireFly; C$5 million cash payment from Treasury Metals; C$2 million cash payment from Big Ridge Gold (3) Value of Joint Venture Interests represents the implied value of First Mining's 20% interest in Pickle Crow upon FireFly's earn-in to 80% of the project derived from FireFly's market cap prior to Green Bay Copper-Gold project acquisition; and the implied value of First Mining's 20% interest in Hope Brook upon Big Ridge's earn-in to 80% of the project derived from Big Ridge's existing market cap TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 4#6GOLD PRICE HAS MOVED, EQUITIES HAVE LAGGED Developers lagging and valuation gap with producers has widened – opportunity to buy now! Relative Performance Since 2022 G FIRST MINING GOLD 40% 30% 20% 10% 0% ww (10%) (20%) (30%) (40%) (50%) (60%) (70%) Jan-22 Mar-22 May-22 Jul-22 Sep-22 Nov-22 Jan-23 Mar-23 May-23 Jul-23 Sep-23 Nov-23 Jan-24 Mar-24 Gold Price GDX GDXJ -Developer Avg Source: Capital IQ Note: Developer average includes FF, KORE, PPTA, TLG, LGD, SKE, TML, WM, ITR, PRB, FURY, STLR, AOT, OIII, VGZ TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com I 30% 5% 0% (40%) | 5#7EXPLORATION WILL NOT SOLVE THE PROBLEM OF DECLINING RESERVES Global gold discoveries have diminished significantly in the last decade Exploration budgets near peak levels with very little demonstrable success G FIRST MINING GOLD Gold Discoveries (Moz Au) Source: Capital IQ 250 200 150 100 50 0 Gold Discoveries & Exploration Budgets Since 1990 $12 $10 $8 $6 $4 ....... $2 $0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Exploration Budgets (US$Bn) | 6#8UNPRECEDENTED VALUE GAP BETWEEN DEVELOPERS AND PRODUCERS First Mining is significantly undervalued on a relative basis compared to peers First Mining trades at a discount to industry peers and has significant re-rating potential G FIRST MINING GOLD First Mining $8 Developer Peers Junior Producers Senior & Int. Producers Source: Based on consensus estimates US$/oz vs. Peer Average $80 TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com $110 P / NAV vs. Gold Industry Peers First Mining 0.10x Emerging Developers Advanced Developers Junior Producers Intermediate Producers $170 Senior Producers 0.34x 0.59x 0.76x 0.99x 1.27x | 7#9LARGE CANADIAN GOLD PROJECTS - CORPORATE ACTIVITY ACCELERATING! G FIRST MINING GOLD Strategic & JVs 2020 2021 2022 AVIA SUMITOMO METAL MINING CO., LTD. IAMGOLD CORPORATION GOLD FIELDS Dec 2022 Cote US$340M 2023 OSISKO MINING May 2023 Windfall C$600M for 50% 2024 ARTEMIS GOLD INC newgold June 2020 Blackwater C$190M + Stream EQUINOX GOLD PREMIER GOLD MINES LIMITED 50% orion centerra GOLD 50% Dec 2020/Apr 2021 Greenstone US$600M Corporate & Asset Acquisitions RESOURCE PARTNERS KINROSS BEAR GREAT RESOURCES Dec 2021 Great Bear C$1.8 Bn B2GOLD Sabina GOLD & SILVER CORP Feb 2023 Back River C$1.1 Bn Calibre MARATHON GOLD Nov 2023 Valentine C$345M ALAMOS GOLD INC. ARGONAUT GOLD Mar 2024 Magino US$325M TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 8#10LARGE PROJECTS IN CANADA REMAIN THE MOST STRATEGIC ASSETS Large projects able to attract partners or buyers even in the toughest markets G FIRST MINING GOLD 20 20 Construction Select Undeveloped Canadian Gold Projects ■ M&I Inferred Gold Resources (Moz Au and AuEq, where applicable) 18 16 5.5 16 14 12 12 10 110 8 13.6 6 11.2 Quebec Construction 0.3 1.8 Construction Quebec Construction Construction 8.3 3.1 1.7 Quebec 2.9 Quebec 12.4 Construction 3.3 0.0 0.3 0.4 <+ 4.5 2.6 5.2 7.6 6.9 7.0 6.3 4.0 1.1 2.3 5.6 5.5 4.9 4.7 4.0 3.4 2.7 1.5 Cote (IAMGOLD) Troilus (Troilus) Tower Gold Blackwater Greenstone (STLLR) (Artemis) (Equinox) Horne 5 (Falco) Back River (B2Gold) Windfall AurMac (Osisko) (Banyan) Moss Duparquet (Goldshore) (First Mining) Hammond Reef (Agnico) Eskay Creek Valentine Springpole Spanish Great Bear (Skeena) (Calibre) (First Mining) Mountain (Kinross) (SPA) OP OP OP OP OP UG OP UG OP OP + UG OP + UG OP OP OP OP OP OP + UG M&I Grade Inferred Grade 0.86 0.66 0.69 Eq 0.69 Eq 0.90 0.92 0.65 Eq 1.27 2.25 Eq 5.88 11.4 1.23 1.55 0.72 3.4 Eq 1.90 1.00 Eq 0.79 2.57 0.53 Eq 3.83 2.23 Eq 6.44 8.4 0.67 1.11 1.62 1.9 Eq 1.65 0.57 Eq 0.74 3.56 Source: Corporate disclosure; S&P Capital IQ TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 9#11THE CUPBOARD IS GETTING BARE List of large developable gold projects is well defined FIRST MINING GOLD OWNS 2 OF THE TOP 10 GOLD DEVELOPMENT PROJECTS IN CANADA Select Undeveloped Canadian Gold Projects G FIRST MINING Gold Resources (Moz Au and AuEq, where 16 Quebec 14 14 3.2 M&I Inferred 12 10 10 Quebec applicable) 8.3 1.7 ∞ Quebec 6 11.2 0.0 0.3 4 2.6 5.2 7.6 7.0 4.5 0.4 2.3 5.6 5.6 4.9 4.7 3.4 2.7 1.5 Troilus (Troilus) Tower Gold Horne 5 (Falco) AurMac (STLLR) (Banyan) Moss Duparquet (Goldshore) (First Mining) Hammond Reef (Agnico) Eskay Creek (Skeena) Springpole (First Mining) Spanish Mountain (SPA) Great Bear (Kinross) OP OP UG OP M&I Grade 0.69 Eq 0.90 2.25 Eq OP+UG 1.23 OP + UG OP OP OP OP OP+UG 1.55 0.72 3.47 Eq 1.00 Eq 0.79 2.57 Inferred Grade 0.69 Eq 0.92 2.23 Eq 0.67 1.11 1.62 1.92 Eq 0.57 Eq 0.74 3.56 Source: Corporate disclosure; S&P Capital IQ TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com GOLD | 10#12FIRST MINING GOLD - VALUE RE-RATING POTENTIAL First Mining is trading at a significant discount to its peers and net asset value Market Value vs. Net Asset Value (C$M) Market Value P/NAV: 0.1x $151 $0.165/share First Mining Market Cap (2) $1,326 Net Asset Value $588 (3) Share Price Re-Rating Potential (C$ / FF share) Does NOT include any value for exploration upside and Cameron Opportunity for Significant Re-Rating and Share Appreciation $1,969 $55 Projects Market Value per Share Cash & Other $2.16/share Springpole Project NPV Duparquet Project NPV Cash & Other (1) Total NAV (1) Includes cash-on-hand, marketable securities, future cash and share payments from partners and value of JV interests (see page 4 for calculation) (2) Based on January 2021 Springpole PFS (3) Based on September 2023 Duparquet PEA TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com G +700% Developer Average: 0.40x to 0.60x $1.35 $1.13 $0.92 $0.70 $0.49 $1.29 $1.07 $0.86 $0.64 $0.17 $0.43 $0.06 $0.11 Current Share 0.20x 0.30x 0.40x 0.50x 0.60x Price 0.1x Springpole P/NAV Multiple Re-Rating P/NAV FIRST MINING GOLD | 11#13PROJECT ECONOMICS OFFERS SIGNIFINCANT LEVERAGE TO GOLD PRICE Unparalleled fundamental value leverage to an increasing gold price G FIRST MINING GOLD SPRINGPOLE DUPARQUET Economic Sensitivity to Gold Price based on PFS Economic Sensitivity to Gold Price based on PEA Pre-Tax Pre-Tax After-Tax Gold Price NPV 5% IRR NPV 5% After-Tax IRR Pre-Tax Pre-Tax After-Tax After-Tax Gold Price NPV 5% IRR NPV 5% IRR US$/oz US$mm % US$mm % US$/oz C$mm % C$mm % $1,400 $1,042 28.9% $690 23.3% $1,600 $621 17.1% $310 12.1% $1,600 $1,482 36.4% $995 29.4% $1,800 $1,070 24.9% $588 18.0% $1,800 $1,921 43.2% $1,297 35.0% $2,000 $1,530 32.0% $859 23.2% $2,000 $2,361 49.5% $1,599 40.1% $2,200 $1,980 38.6% $1,120 28.0% Each US$100/oz movement in gold price adds US$250M in fundamental net asset value to our projects! Source: Springpole 2021 PFS and Duparquet 2023 PEA TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 12#14LOOKING AHEAD TO 2024 → Submission of final EA/EIS for the Springpole Gold Project targeted in summer 2024 → Continue 20,000m+ drilling program at Duparquet Gold Project to build on discovery success in 2023 Results from the exploration program at the Birch Uchi Greenstone Belt project (Springpole regional) Progress on community relations at both Springpole and Duparquet Preparation of a Feasibility Study at the Springpole Gold Project G FIRST MINING GOLD Evaluate non-dilutive sources of financing such as the strategic monetization of additional non-core assets TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 13#15SPRINGPOLE - A UNIQUE STRATEGIC GOLD ASSET One of the largest, undeveloped open-pit gold deposits in Canada • Probable Reserves of 3.8 million ounces gold at 0.97 g/t, 20.5 • million ounces silver at 5.2 g/t Average annual gold production of 335,000 ounces in years 1 through 9(1) Positive Economics, +11 year mine life • PFS announced January 2021, post-tax NPV 5% of US$995 million and post-tax IRR of 29% (1) Tier 1 Mining Jurisdiction with District Scale Exploration Upside • Long history of gold production in the area Unique Strategic Gold Asset • One of only a few projects in Canada able to produce more than 300,000 oz per year Existing Infrastructure In Place • 44-person camp, nearest logging road access 18 km from camp, powerline within 40 km of proposed plant (1) See page 28 for further details and disclosure regarding the 2021 Springpole PFS TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com N CAT LAKE PICKLE CROW BIRCH-UCHI PROJECTS AUTECO MINERALS Red Lake RED LAKE Gold Mine (Evolution) Dixie EAR FALLS KENORA Rainy River (New Gold) ONTARIO SLATE FALLS SPRINGPOLE LAC SEUL SIOUX LOOKOUT DRYDEN TREASURY Goliath (Treasury Metals) Goldlund (Treasury Metals) CAMERON G PICKLE LAKE Hammond Reef (Agnico Eagle) 0 50 Km FIRST MINING First Mining Projects Road Logging Road Power Line Advanced Gold Projects ⑭Producing Mine ● Town/Community + Airport GOLD | 14#16SPRINGPOLE - 2021 PFS RESULTS (1) Base Case Highlights: Au Price: US$1,600/oz After-Tax NPV5 5% US$995 million Ag Price: US$20/oz After-Tax IRR 29.4% S Production LOM Year 1 to 9 Mine Life yr 11.3 9.0 FX: LOM Strip Ratio W:0 2.36 2.30 0.75 Daily Throughput tpd 30,000 Gold Gold Head Grade g/t 0.97 1.12 Gold Recovery % 85.7% 87.0% Total Payable Gold koz 3,225 3,018 LOM Year 1-9 Pre-Tax NPV. 5% US$1.5 billion Annual Production 335 koz Annual Production 287 koz Initial Capex US$718mm Pre-Tax IRR 36.4% AISC (net of silver) US$577/oz AISC (net of silver) US$645/oz Sustaining Capex US$55mm Economic Sensitivity to Gold Price AISC (net) Cash Costs AISC Capital Cost Average Annual Gold koz 287 335 Peak Gold Production (Year 3) koz 400 400 Silver Silver Head Grade g/t 5.2 5.7 Silver Recovery % 89.5% 89.8% Total Payable Silver koz 18,117 16,077 Average Annual Silver koz 1,610 1,786 Operating Costs US$/oz $618 $558 US$/oz $645 $577 US$/oz AuEq $673 $612 US$/oz AuEq $698 $631 Pre-Tax Pre-Tax After-Tax Gold Price NPV 5% IRR NPV 5% After-Tax IRR Initial Capex US$mm $718 Sustaining Capex US$mm $55 US$/oz US$mm % US$mm % Closure Cost US$mm $29 $1,300 $822 24.8% $537 20.0% Total Capital US$mm $803 $1,400 $1,042 28.9% $690 23.3% $1,600 $1,482 36.4% $995 29.4% $1,800 $1,921 43.2% $1,297 35.0% $2,000 $2,361 49.5% $1,599 40.1% IRR Economics NPV (5%) Payback Pre-Tax Post Tax US$mm $1,482 $995 % 36.4% 29.4% yr 2.2 2.4 Cash Costs (net) (1) See page 28 for further details and disclosure regarding the 2021 Springpole PFS TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com FIRST MINING GOLD | 15#17SPRINGPOLE - CONCEPTUAL MINE SITE LAYOUT ONE210M FMG Sinopole E1811 GIBLESMXDS Pan Am Co-Disposal Facility TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Birch Lake North Cell Co-Disposed Filtered Tailings and Mine Rock L-16 South Cell CDF Internal Pond Over Slurry Tailings Tailings Li Pipeline Explosive Storage Phase 1 Pit Main Open Pit Low Grade Ore Stockpile Contact Water Management Pond High Grade Ore Stockpile Mid Grade Ore Stockpile Water Storage Pand Plant Site Pond (WSP) Birch Lake Distribution Line Contact Water Management Pond Fresh Water Intake Pipeline Process Plant Area L-10 Fish Habitat Development Area Surficial Soll Stockpile East Cofferdam 230 kV -Transmission Lina Accommodations. Complex Mine Access Road Emuent Discharge Pipeline West Cofferdam Springpole Lake Springpole Lake C-15) (L-15) G FIRST MINING GOLD Dale Lake L:20 | 16#18- COORDINATED FEDERAL – PROVINCIAL EA PROCESS FOR SPRINGPOLE 2018 2019 2020 2021 2022-2024 2024 - 2025 Evaluate project, gather info and study effects Review the EA / EIS Make EA decision Determine if EA is required (federal) and Plan EA (federal-provincial) Ongoing opportunities for consultation and engagement with Indigenous communities Provincial EA 2009 Proponent conducts Voluntary agreement Proponent prepares TOR ToR review Minister's decision on final ToR Federal EA studies, consults/ engages, and prepares draft EIS/EA in accordance Release of the draft EIS/EA for review, input and Proponent updates EIS/EA based on feedback Submiss ion of the final EIS/EA Coordinated federal- provincial review of, and consultation on draft EIS/EA Proponent submits draft Project Description Proponent submits final Project Agency issues EIS Guidelines with approved TOR/EIS Guidelines consulta tion¹ Description Formal opportunity for Indigenous consultation & public participation We are here Step completed 1 The release of the draft EIS/EA is not part of the regulatory process but is common practice TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Ministry Review published on final EIS/EA Post EA Approvals/ Permits G FIRST MINING GOLD Provincial EA decision Permits & Approvals Mitigation & Monitoring on, EIS/EA Report Agency prepares draft and final EA Report Federal EA decision Compliance & Enforcement Acronyms EA - Environmental Assessment EIS - Environmental Impact Statement TOR Terms of Reference | 17#19SPRINGPOLE RESOURCE & EXPLORATION POTENTIAL RESOURCE CONVERSION, GROWTH, AND CONFIDENCE Advancing prospectivity in and around current pit with focus on opportunities for conversion, extension and additional discovery CONVERSION Springpole Inferred resources opportunity • Potential to convert Inferred to Indicated, increasing available resource ounces • Majority of Inferred located in the south of the current pit EXTENSIONS & UNDER-EXPLORED AREAS Direct open mineralization trends & opportunity for additional discovery . SW Extension target zone remains open in multiple directions SP22-ARD-007 G FIRST MINING GOLD SOUTHWEST & EAST EXTENSION ZONE SP22-ARD-008 Block Model (2021 PFS) Indicated Inferred SP22-ARD-012 SP22-ARD-011 SG22-008 Portage Zone SG22-019 E Extension SG22-021 SG22-027 SG22-029 SP22-ARD-010 SW Extension SP22-ARD-013 SG22-023 SG22-017 SP22-ARD-006 • • • SG22-008 intersected 1.01 g/t Au over 30.0 m from 300.0 - 330.0 m SG22-021 intersected 0.98 g/t Au over 33.0 m from 252.0 - 285.0 m, including 2.87 g/t Au over 7.0 m from 264-271 m SG22-027 intersected 2.14 g/t Au over 10.7 m from 228-238.7 m, and 0.51 g/t Au over 30.0 m from 255.0 - 285.0 m Newly identified opportunities within Eastern Extension Zone & Portage Zone Advanced structural study commenced in 2023 & will be concluded in 2024 Critical Minerals study underway in collaboration with Ontario Geological Survey, including assessment of tellurium, flourite, and lithium potential Drill Trace 2022 2021 Reported Intercept Au g/t >10 5-10 2-5 1-2 0.3-1 <0.3 SP22-ARD-005 SP22-ARD-004 SG22-012 SG22-020 T الالا Looking NNW metres For further information on the SW Extension Zone, see news release dated 12 April 2023: first-mining-completes-development-drilling-and-expands-mineralization-potential-at-springpole-with-sw-extension-zone TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 18#20BIRCH-UCHI PROJECT - EXPLORATION POTENTIAL Strategic Regional Consolidation Surrounding Springpole Advancement of district scale exploration opportunities spanning >70,000 hectares of land tenure • Brownfields: Targeting areas for potential satellite resources and large scale discovery Greenfields: District exploration screening & evaluation with continued advancement of field mapping, soil geochemistry and channel sampling throughout 2023, as well as continued processing & targeting of 2022 airborne geophysics survey (3,843 line km) Year 2 Year 3+ Mineral Reserves 2+ Mineral Resource Targets Key 5 Drive Advanced Targets Top 10 Focus Strategy Follow up Targets 80+ Generational Stage Targets Identified Target Areas TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Burch Deformation Zone Swain Deformation Zonex Swain Deformation Zone ** 20 10 Kilometers G FIRST MINING GOLD Birch Lake | 19 N#21BIRCH-UCHI PROJECT - EXPLORATION HIGHLIGHTS GREEN CAMB SADDED 1050m SWL22-003 Successfully Drill Tested 4 Exploration Targets Swain •Identification of key exploration elements in the Grace Deformation Zone over a structural strike length of 6.5 km; drill intersects of up to 0.64 g/t Au over 5.6 m, and 0.34 g/t Au over 14.9 m (drill hole SWL22- 001) •Discovery of new gold-in-soil anomaly, including a gold assay of 724 ppb Au, with open opportunity for expansion and infill Saddle •Initial drilling campaign returned consistent gold mineralization over meaningful widths that remains open for expansion •Drill intersects include 0.92 g/t Au over 114.0 m in hole SAT23-001, and 0.75 g/t Au over 57.7 meters in drill hole SAT23-002 • 2023 Discovery highlights FIRST MINING GOLD Exploration assay results have identified a new near-surface and high priority structural setting for gold mineralization approximately 375 m from the recently drill tested Saddle target which returned 0.92 g/t Au over 114 m Rock samples assayed at the now-established Challenger target are encouraging, as highlighted by the discovery of two new mineralized occurrences approximately 60 m apart, where grab samples have returned gold values including 25.60 g/t Au, 7.10 g/t Au and 4.42 g/t Au Further gold assays associated with the Challenger target now define an interpreted east-west trending gold mineralized shear structure over an approximately 60 m trend, which remains open both along strike and at depth. 532000 534000 536000 538000 540000 542000 544000 546000 548000 550000 HOR23-004 MOR23-005 HOR23-002 EM PLATES BIR23-001 Horseshoe •Successfully intersected mineralization over a 260-m strike length with drill highlights including 0.48 g/t Au over 48.5 m in drill hole HOR23-001, 0.54 g/t Au over 57 m in drill hole HOR23-002, and 0.64 g/t Au over 24 m and 0.45 g/t Au over 14.5 m in drill hole HOR23-003 5696000- 5694000- Atlantis •Focused on EM plate modelled targets identified in the 2022 airborne geophysics campaign •Drilling aimed at discovering new gold mineralization in analogous structural and stratigraphic settings to other known mineralized occurrences on the property •Technical success on testing newly developed generative targets Further information on the 2023 drilling & Exploration updates can be found at: https://firstmininggold.com/news/ S TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Shabumeni Birch Loke 5692000- Swan Deformation, Horseshoe 5690000- 5688000- n Deformatio Swain Deformation Zone CHALLENGER New Discovery Target Challenger Highlights: Grab samples 25.6 g/t Aut 7.10 g/t Au 4.2 g/t Au Satterly 375m SADDLE Saddle Highlights: Drill Intersects Birch Deformation Zone Cassumi SPRINGPOLE -5696000 -5694000 Horseshoe East Springpole Highlights: Mineral Resource Indicated: 4.6 Moz Au Inferred: 0.3 Moz Au -5692000 Satterly -5690000 Map Extent ONTARIO Timmins 5-5688000 Kenoga Thunder Bay Ottawa Toronto -5686000 542000 544000 546000 548000 550000 5686000- Swain Stargazer 0.92 g/t Au over 114m 0.75 g/t Au over 57.7m $32000 $34000 536000 538000 540000 Legend Springpole Regional geology Source: Ontario Geological Survey Conglomerate Challenger Saddle Deformation Zones First Mining Land Tenure Mafic volcanics Felsic tuff Porphyry FIRST Challenger Target Location Gabbro Syenite MINING GOLD Granite Tonalite Granodiorite Volcano-sedimentary 0 Intermediate tuff Kilometers Wacker | 20#22S FIRST MINING GOLD Duparquet Project#23DUPARQUET - AN ADVANCED STAGE ASSET • Released Positive PEA in September 2023 Revitalizes a historical past-producing Quebec gold district Located on the Destor-Porcupine Fault Zone - only 50 km from Rouyn- Noranda • 233 koz Au annual LOM recovered at AISC less than US$1,000 over 11-year mine life • C$588M after-tax NPV at 5% and 18% IRR at US$1,800/oz Updated mineral resource estimate in August 2023 meaningfully enhances resource profile of First Mining and Quebec presence • 3.4 Moz gold in the Measured & Indicated category, plus 2.6 Moz gold in the Inferred category at Duparquet . Includes two previously 100% owned deposits, Pitt Gold and Duquesne Significant historical drilling with exploration upside . Mineralized zones open along strike and at depth to complement more than 270,000 m of historical drilling completed between 2008 and 2013 Completed new 5,000m exploration drill program confirming a new modeled zone with significant drill intercepts; Phase II program now commenced Highly experienced and accomplished Quebec-based environmental team in place • Direct previous experience with large scale mining reclamation development, including most recently at the Hardrock project TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com 0000/$$ BEATTIE 610000 620000 630000 Property Name Rapide Danseur Town of Duparquet Duparquet Porcupine East Duquesne Pitt Historical Mine Amtfield DONCHESTER CENTRAL DUPARQUET LAMGOLD DUMICO 4 5 km IAMGOLD 640000 Duparquet Gold Project Abi-Ouest Pitt Gold G FIRST MINING GOLD 650000 660000 670000 Duquesne D'Alembert QUEBEC Rouyn-Noranda Rouyn-Noranda PITT GOLD McWatters Airport 0 Kilometres 20 DUQUESNE N 5360000 5350000 Consolidated Tenure | 22#24DUPARQUET | LOCATED IN THE PROLIFIC ABITIBI GREENSTONE BELT Operating Mine Deposit Historical Mine 1:2311162 50 km T Timmins Gold Camp +70 Moz Porcupine Kidd Bell Creek/Timmins West 30 mile Source: digigeodata; public disclosure TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Detour Lake Casa Berardi +200 Moz Gold Produced in the Abitibi! Destor Porcupine Fault Lac Abitibi Duparquet Project Macassa Rouyn-Noranda Young- Davidson Kirkland Lake Gold Camp +40 Moz Temiskaming Shores Malartic Rouyn-Val d'or Gold Corridor +70 Moz Canadian Malartic LaRonde Lamaque Goldex Val d'or Zec Capitachouane Réserve faunique La Vérendrye Larder Lake Cadillac Fault Kipawa categorie Zec Festubert Zec Petawago G FIRST MINING GOLD ZEC Lesueur Zec Mitchina | 23#25DUPARQUET PEA HIGHLIGHTS LOM Annual 233 koz Au Initial Capital C$706 M Recovered Au Total Produced Au Oz 2.5 Moz Au After-Tax NPV @ 5% C$588 M LOM Cash Costs US$751/oz After-Tax IRR 18.0% LOM AISC US$976/oz After-Tax Payback 4.8 Years G FIRST MINING GOLD Notes: • • . Base case parameters assume a gold price of US$1,800/oz and an exchange rate (C$ to US$) of 1.33. All currencies are reported in U.S. dollars unless otherwise specified. NPV calculated as of the commencement of construction and excludes all pre-construction costs. Cash costs consist of mining costs, processing costs, mine-level G&A, treatment and refining charges and royalties. AISC consists of cash costs plus sustaining and closure costs. The PEA is preliminary in nature, that it includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that the PEA will be realized Note: Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 24#26DUPARQUET PEA PRODUCTION PROFILE - VS GRADE Average annual recovered gold production of 233 koz over 11-year mine life Opportunities to increase mine through resource expansion, feed from satellite deposits and regional milling Average OP grade of 1.36 g/t Au; average UG grade of 2.25 g/t Au Duparquet PEA Production and Grade Profile Gold Production (koz) 4.79 1,000 800 Gold OP Grade -O-UG Grade G FIRST MINING GOLD 5.0 4.0 600 3.0 8.37 2.42 2.25 2.24 2.31 2.13 2.23 2.29 2.18 2.22 1.80 400 1.66 2.0 1.51 1.53 1.30 1.34 1.31 1.20 1.18 1.09 1.03 200 1.0 272 255 276 186 223 236 238 223 231 211 217 0 0.0 1 2 3 4 5 6 7 8 9 10 11 Production Year Note: Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Au Grade (g/t Au) | 25#27DUPARQUET PEA SUMMARY $ FIRST MINING GOLD Key Assumptions LOM Operating Costs (US$/oz)(1) LOM Gold Price US$/oz US$1,800 Cash Costs (US$/oz) (2) US$/oz $751 Exchange Rate (C$:US$) 1.33 AISC (US$/oz)(3 ) (3) US$/oz $976 Production Profile LOM Capital Expenditures LOM Total Open Pit Tonnage Mt 282 Initial Capital C$M $706 Total Open Pit Ore Mt 43.6 Sustaining and Development Capital C$M $738 Open Pit Strip Ratio W:0 5.4 Net Closure Costs C$M ($6) Total UG Ore Mt 12 Estimated Salvage Value C$M ($36) Total Tailings Ore Total Tonnes Processed Throughput Mt 4.1 Economics - Pre-Tax LOM Mt 59.7 NPV at 5% D.R. C$M $1,073 tpd 15,000 IRR % 24.9% Mill Grade Mine Life g/t Au 1.51 Payback years 3.8 years Recovery LOM Metal Recovered years % 11 years Economics - Post-Tax LOM 89.5% NPV at 5% D.R. C$M $588 koz Au 2,595 IRR % 18.0% Average Annual Recovered koz Au 233 Payback years 4.8 years Operating Costs per Tonne LOM Mining Costs - OP C$/t mined $3.16 STRONG LEVERAGE TO GOLD PRICE UPSIDE Mining Costs - OP C$/t $20.85 Gold Price Mining Costs - UG C$/t $44.26 Processing Costs C$/t $10.59 G&A Costs C$/t Total Operating Costs C$/t $2.90 $78.60 23.2% Note: Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com Pre-Tax NPV5 Pre-Tax IRR After-Tax NPV 5% After-Tax IRR 5% US$1,600 C$621 M 17.1% C$310 M 12.1% US$1,800 US$2,000 US$2,200 C$1.07 B 24.9% C$1.53 B C$1.98 B 32.0% 38.6% C$588 M 18.0% C$859 M C$1.12 B 28.0% TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 26#28DUPARQUET RESOURCE PROFILE G FIRST MINING GOLD S Duparquet open pit resource shows a potential higher grade opportunity with an Indicated resource of 1.5 Moz at 2.1 g/t Au, at a cut-off of 0.7 g/t (see Table 2) Mineralized zones are open along strike and at depth, with majority of historical drilling less than 500 m from surface; high-grade mineralized Abitibi structures prominent at 1,000 m depth Duparquet Mineral Resource Estimate - September 2022 Potential higher-grade open pit with attractive grade flexibility Area (Mining Cut-off Drilling Depth at Duparquet Majority of drill testing less than 500 m from surface and open at depth Measured Resource Indicated Resource Inferred Resource Au Method) (g/t) Tonnage (t) Ounces Tonnage (t) Open Pit 0.40 163,700 (g/t) 1.37 7,200 UG Mining 1.50 Tailings Total 0.40 19,900 183,600 2.03 1.43 1,300 8,500 59,410,600 5,506,900 4,105,200 69,022,700 Au (g/t) 1.52 Ounces Tonnage (t) 2.26 0.93 2,909,600 399,300 123,200 Au (g/t) 28,333,000 1.07 9,038,900 PLAN VIEW DUPARQUET Ounces 2.29 970,400 665,600 1.55 3,432,100 37,371,900 1.36 1,636,000 AU_FINAL_DDH X 0.6 0.200006666 0.100008333 0.00001 Table 1: 2022 Mineral Resource Estimate for the Duparquet Project, by Mining Method Measured Resource Indicated Resource Inferred Resource Area (Mining Method) Cut-off (g/t) Au Tonnage (t) Ounces Tonnage (t) (g/t) 0.7 137,321 1.53 6,755 0.65 141,757 1.5 6,836 0.6 149,158 1.46 0.55 154,634 1.42 Open Pit 0.5 156,938 0.45 161,081 1.41 1.39 0.4 0.35 163,709 165,800 1.37 1.36 23,142,210 25,666,698 7,001 32,690,577 7,060 36,556,977 7,122 41,152,335 7,187 53,548,726 7,222 59,410,612 1.52 7,248 66,307,600 Au (g/t) 2.05 Ounces Tonnage (t) Au (g/t) Ounces SECTION VIEW DUPARQUET 1,525,279 2,592,695 1.62 135,038 1.98 1,633,902 3,334,098 1.48 158,647 1.86 1.77 1.70 1,954,908 5,716,620 1.34 246,283 2,080,340 7,727,020 1.23 305,568 1.58 1.46 2,253,068 11,007,061 2,722,586 22,032,449 2,909,551 28,332,980 3,117,172 37,354,222 0.96 1.13 400,881 1.16 824,601 1.07 970,424 1,147,282 Table 2: 2022 Cut-Off Grade Sensitivity for the Duparquet Project Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, and which is available at First Mining's website or under First Mining's SEDAR+ profile TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com 631000 652000 X 500 688000 B00 Z-Scale 1500 Plunge 90 Azmuth G AU_FINAL_DDH X 0.61 630000 0.200006666 0.100008333 0.00001 Z-Scale 1 1000 1500 Plunge 1 Azimuth 0 | 27#29UPDATED DUPARQUET RESOURCE - SEPTEMBER 2023 PEA Duparquet deposit mineral resource estimated updated in Sept 2022 First Mining's 100% owned Pitt Gold and Duquesne deposits mineral resource estimate updated in Aug 2023 and will form part of the consolidated Duparquet Gold Project Increases Inferred Mineral Resource by more than 1 Moz Au Total M&I of 3.4 Moz Au and Inferred of 2.6 Moz Au Consolidated Duparquet Gold Project Mineral Resource Estimate G Duparquet Deposit Mineral Resource Estimate (Sept 2022) Area Cut- (Mining off Method) (g/t) Measured Resource Indicated Resource FIRST MINING Inferred Resource Tonnage Au (g/t) Ounces Tonnage (t) Au (g/t) Ounces Tonnage (t) Au (g/t) Ounces Open Pit 0.40 163,700 1.37 7,200 59,410,600 1.52 2,909,600 28,333,000 1.07 970,400 UG Mining 1.50 5,506,900 2.26 399,300 9,038,900 2.29 665,600 Tailings 0.40 19,900 2.03 1,300 4,105,200 0.93 123,200 Total 183,600 1.43 8,500 69,022,700 1.55 3,432,100 37,371,900 1.36 1,636,000 GOLD Pitt Gold & Duquesne Deposits Mineral Resource Estimate (Sept 2023) Measured Resource Indicated Resource Inferred Resource Pitt Gold Inferred Resource Duquesne Inferred Resource Area (Mining Method) Tonnage (t) Au (g/t) Ounces Tonnage (t) Au (g/t) Au Ounces Tonnage (t) Ounces Area (Mining Method) Cut-off (g/t) (g/t) Tonnage (t) Au (g/t) Ounces Tonnage (t) Au (g/t) Ounces Open Pit 163,700 1.37 7,200 59,410,600 1.52 2,909,600 34,633,000 1.16 1,286,400 Open Pit 0.50 6,300,000 1.56 316,000 UG Mining 5,506,900 2.26 399,300 16,189,000 2.60 1,354,100 UG Mining 1.75 2,120,000 2.75 187,200 5,030,000 3.10 501,400 Tailings 19,900 2.03 1,300 4,105,200 0.93 123,200 Total 2,120,000 2.75 187,200 11,330,000 2.24 817,400 Total 183,600 1.43 8,500 69,022,700 1.55 3,432,100 50,822,000 1.62 2,640,500 Note: Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 28#30DUPARQUET WORK PLAN Prioritize developing relationship with local municipalities, Indigenous communities and regulators G FIRST MINING GOLD → Environmental baseline data collection • Substantial preliminary reclamation and environmental data collection already commenced including water testing, addressing existing legacy infrastructure on site, addressing environmental legacy from historical operation and site safety audit Work in partnership with Quebec ministries to develop alternatives to address environmental legacy Preliminary Economic Assessment ("PEA") announced in September 2023 Ongoing Optimization and Trade Off Reviews Duparquet exploration and expansion drilling programs commenced in May 2023 Phase I drill program of 5,000m (completed) Phase II drill program of 5,000m commenced and continuing through Q2 2024 Phase III program under planning for initiation Q3 2024 Geophysics and Lidar programs under consideration for 2024 TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 29#31Taronde 2.5 Moz Bousquet 15.0 Mot Lapa 1.2Moz ပြာ G FIRST MINING GOLD FIRST MINING GOLD EMPEROR METALS BARRICK DUPARQUET EXPLORATION OPPORTUNITIES District Discovery - THE ABITIBI OPPORTUNITY • • Modelling expansion of regional district targeting on over 19km of the DPFZ-a prolific gold affinity Leverage to consolidated land tenure of ~6000 hectares Discovery opportunity for new Au hosted deposits in mafic volcanics, ultramafic and sediments stratigraphy Field program focuses on data gap integration with consolidation approach - geophysics, lidar, mapping structure, and litho- geochemistry with diamond drilling of priority targets happening now. Extensional and Near Resource Opportunities Diamond drilling of near resource exploration opportunities seeking to identify areas of significant ounce potential 4x3 km 3D litho-structural-mineralization model with targeting in immediate 300m of the resource wireframe identifies >20 targets with a total potential endowment of a factored 2-5Moz. Approximately 30,000 meters of initial scout level drilling planned. Prioritized for scale and opening of the exploration space Deep Drilling - Long Lived Asset Program – Think BIG - Duparquet Au endowment of ~1M Oz per 100m vertical expression Deepest level of drilling approximately 615m - shallow by Abitibi standards • Several individual holes with positive grades at ~750m vertical Drilling of key plunge horizons to below 1000m meters could evolve significant reward and re-rate opportunity for the project TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Timmins Camp 65.0 Moz H.H McDermot Casa Berardi % 5.1 Mor Duparquet 1.6 Mor Noranda 18.0 Mor 父 Black Fox 2.6 Moz Ross 2.6 Mor Destor-Porcupine Fault Zone 1.1 Moz Young Davidson 3.4 Moz ㄨㄨ Westwood Matachewan Fault Zone Upper Canada 1.9 Moz Kerr Mine 11.0 Moz Francoeur 1.0 Mor Wasamac 2.7 Joanna 25 Mor 3.7 Moz 2.0 Moz Cadillac-Larder Lake Juby Gold Project 3.0 Moz Gowganda Ridout Aldershot Resources Gowganda Property 3.0 Moz-Gold Google earth Fault Zone Gowganda Silver Camp 70 Maz Ag Produced Ontario Quebec 600m MINED + RESOURCE INVENTORY TO ~650M AGNICO EAGLE | 30#32DUPARQUET EXPLORATION UPDATE 2023 UPDATE • First Mining has completed 17 exploration drill holes totaling 6,966 m in its 2023 exploration drilling campaign which focused on initial drill testing of key targets across the project N Re Matheon Rue Principale • First Mining commenced a foundational drilling program in May 2023 with a campaign that is focusing on the advancement of newly defined targets, as well as validating and expanding on resource growth and optimization opportunities. Results returned from the exploration drill holes are continuing to demonstrate that this project has significant potential across the wholly-owned land tenure, through the confirmation of the new zones and targets at Central Duparquet, as well as the previously announced Buzz Zone Link to news releases 2023 Completed Holes Phase 1 Holes Phase 2 Holes Centimeters Legend Open Pit Design Drill Trace 2023 Resource Wireframe Syenite PDFZ Duparquet Mafic Volcanic Ultramafic Mafic Intrusive Porcupine Sediments Timiskaming Sediments Kewagama Sediments 250 500 750 1000 DUP23-002 N Map Extents DUP23-003 DUP23-005 BUZZ ZONE TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com CDHG ZONE DUP23-007 DUP23-008 DUP23-006 Dumico Central Duparquet VALENTRE TARGET DUPARQUET S FIRST MINING GOLD 0 0.3 0.7 1.3 2 Kilometers FIRST MINING GOLD FMG defines new gold zone: 6.52 g/t Au over 4.6m in Phase I Drilling campaign at Duparquet Gold Project MINING GOLD FIRST MINING GOLD First Mining Identifies Expansion Opportunities at Central Duparquet Target Areas 1.71 g/t Au over 8.90m: Valentre target confirming mineralization strike extension 2.73 g/t Au over 6.15m: CDHG Zone Unlocks mineralization at depth | 31#33OTHER ASSETS PROVIDE OPTIONALITY First Mining owns several wholly owned and joint venture projects that provide optionality Pickle Crow (30%) FireFly • METALS . Description Operated by FireFly Metals (ASX:FFM) Located in Ontario FireFly has right to earn up to an additional 10% interest for C$3M cash Resource Profile • 1.23 Moz Inferred Resource • Of this, 369 koz attributable to First Mining Hope Brook (20%) BIG RIDGE -GOLD CORP- • Operated by Big Ridge Gold (TSXV:BRAU) • Located in Newfoundland • • First Mining JV interest free carried to a feasibility study • • . Cameron (100%) G FIRST MINING GOLD • Treasury Metals TREASURY METALS Inc. • • Other Details G FIRST MINING GOLD First Mining JV interest free carried to decision to mine 1.2 Moz Indicated Resource and 231 koz Inferred Resource Of this, 241 koz Indicated Resource and 46 koz Inferred Resource attributable to First Mining' C$2M payable to First Mining on commercial production Wholly owned and operated by First Mining Located in Ontario approximately 80 km north of New Gold's Rainy River mine 53k ha land package • 464 koz Measured & Indicated Resource and 533 koz Inferred Resource Goliath Gold Complex wholly owned and operated by Treasury Metals (TSX:TML) Located in Ontario First Mining owns 20M shares of TML TML acquired First Mining's former Goldlund project in 2020 to create the current complex TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com • • 2.1 Moz Measured & Indicated Resource and 0.8 Moz Inferred Resource · • Consolidated strategic part of Cameron project by acquiring East Cedartree claims C$2.5M payable to First Mining on receipt of permits at Goldlund C$2.5M payable to First Mining upon extraction of 300,000 t of ore at Goldlund Sold 1.5% NSR royalty on Goldlund to Sprott Streaming and Royalty in December 2022 for C$9.5M | 32#34FIRST MINING GOLD For more information: [email protected] +1 604 639 8824 TF: 1 844 306 8827 www.firstmininggold.com in V ཆ#35ADDITIONAL INFORMATION#36FIRST MINING - MINERAL RESERVE & MINERAL RESOURCES S FIRST MINING GOLD Springpole Project Tonnes 121,600,000 Probable Reserves Au Grade (g/t) 0.97 Contained Au (oz) 3,800,000 Ag Grade (g/t) 5.23 Contained Ag (oz) 20,500,000 Note: This mineral reserve estimate is as of December 30, 2020 and is based on the new mineral resource estimate dated July 30, 2020. The mineral reserve calculation was completed under the supervision of Gordon Zurowski, P.Eng of AGP Mining Consultants Inc., who is a Qualified Person as defined under NI 43- 101. Mineral reserves are stated within the final design pit based on a US$878/ounce gold price pit shell with a US$1,350/ounce gold price for revenue. The equivalent cutoff grade was 0.34 g/t Au for all pit phases. The mining cost averaged CAD$ 1.94/tonne mined, processing averages CAD$ 14.50/tonne milled, and G&A was CAD$ 1.06/tonne milled. The process recovery for gold averaged 88% and the silver recovery was 93%. The exchange rate assumption applied was CAD$1.30 equal to US$1.00. Measured Resources Project Springpole (1)(2) Springpole - Ag (1)(2) Tonnes Indicated Resources Au Grade (g/t) Contained Au (oz) Tonnes Inferred Resources Au Grade (g/t) 151,000,000 0.94 4,600,000 16,000,000 0.54 Contained Au (oz) 300,000 5.0 (Ag) Duparquet (3) 183,600 1.43 Cameron (4) 3,360,000 2.75 8,500 297,000 69,022,700 2,170,000 1.55 24,300,000 (Ag) 3,432,100 2.8 (Ag) 1,400,000 (Ag) 50,822,000 1.62 2,640,500 2.39 167,000 6,535,000 2.54 533,000 Pickle Crow (30%) (5) 2,835,600 4.10 369,150 Hope Brook (20%) (6) Total 3,543,600 2.68 305,500 3,238,000 225,430,700 2.32 241,200 443,000 3.24 46,200 1.16 8,440,300 76,635,500 1.57 3,888,950 Pickle Crow: Joint venture with FireFly Metals; 30% ownership to First Mining Hope Brook: Joint venture with Big Ridge; 20% ownership to First Mining Note: Table based on most recent NI 43-101 technical reports filed on SEDAR+ by First Mining Gold Corp. Further details available at: https://firstmininggold.com/projects/mineral-resources/ Springpole mineral resources are inclusive of mineral reserves. Open pit mineral resources are reported at a cut-off grade of 0.3 g/t Au. Cut-off grades are based on a price of US$1,550/oz Au and $20/oz Ag, and processing recovery of 88% Au and 93% Ag. Silver (Ag) resource shown on separate line with grade representing g/t Ag, and contained ounces representing Ag. (1) (2) (3) (4) (5) (6) The Duparquet Consolidated Mineral Resource Estimate represents a combination of the resources at the Duparquet, Pitt Gold and Duquesne deposits. For Duparquet, the mineral resource estimate is classified as Measured, Indicated and Inferred. For Pitt Gold and Duquesne, the mineral resource estimates are completely classified as Inferred. Duparquet deposit resources are reported at a cut-off grade of 0.4 g/t Au (in-pit and tailings) and 1.5 g/t Au (underground). Duquesne open pit resources are reported at a cut-off grade of 0.5 g/t Au, and Pitt Gold and Duquesne underground resources are reported at a cut- off grade of 1.75 g/t Au. Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com Measured resources comprised of 2,670,000 tonnes of pit-constrained (0.55 g/t Au cut-off) Measured resources at 2.66 g/t Au, and 690,000 tonnes of underground (2.00 g/t Au cut-off) Measured resources at 3.09 g/t Au. Indicated resources comprised of 820,000 tonnes of pit-constrained (0.55 g/t Au cut-off) Indicated resources at 1.74 g/t Au, and 1,350,000 tonnes of underground (2.00 g/t Au cut-off) Indicated resources at 2.08 g/t Au. Inferred resources comprised of 35,000 tonnes of pit-constrained (0.55 g/t Au cut-off) Inferred resources at 2.45 g/t Au, and 6,500,000 tonnes of underground (2.00 g/t Au cut-off) Inferred resources at 2.54 g/t Au. Comprises 1,887,000 tonnes of pit-constrained (0.50 g/t Au cut-off) Inferred resources at 1.3 g/t Au, and 7,565,000 tonnes of underground Inferred resources that consist of: (i) a bulk tonnage, long-hole stoping component (2.00 g/t Au cut-off); and (ii) a high-grade cut-and-fill component (2.6 g/t Au cut-off) over a minimum width of 1 m. First Mining owns 30% of the Pickle Crow Gold Project, and 70% is owned by FireFly Metals Ltd. The Inferred mineral resources for Pickle Crow shown in the above table reflects only the First Mining ownership interest. First Mining owns 20% of the Hope Brook Gold Project, and 80% is owned by Big Ridge Gold Corp. The mineral resources for Hope Brook shown in the above table reflect only the First Mining ownership interest. For details of the resource, see news release from Big Ridge Gold Corp. from February 21, 2023. TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 35#37BOARD OF DIRECTORS G FIRST MINING GOLD Keith Neumeyer Chairman & Founder Mr. Neumeyer has worked in the investment community since 1984. He has an unparalleled track record which includes creating two world-class mining companies: First Quantum Minerals Ltd. which has now grown into one of the world's largest copper producers, and First Majestic Silver Corp. which is one of the largest silver producers in the world. Dan Wilton CEO & Director Dan Wilton has 25 years of experience in M&A, corporate finance and principal investing in the mining sector. He was most recently a Partner at Pacific Road Capital Management, a mining-focused private equity investment firm with approximately $800 million under management. His prior role includes Managing Director and Head of the Global Mining and Metals Group at National Bank Financial Inc. Ray Polman Director Ray has more than 30 years of public accounting and corporate finance experience in the Canadian and U.S. financial markets and most recently served as CFO for First Majestic Silver until January 2022. Prior to First Majestic, he was CFO for six years with a number of publicly traded high technology companies and served several years as the Director of Finance for Rescan Environmental. Richard Lock Director Richard is a veteran mining executive with more than 30 years of experience in project management, development and operations for major mining companies including Rio Tinto, Western Potash, DeBeers and Anglo American. Richard is currently CEO and Director of Oroco Resources Corp. and was previously Senior Vice President and Project Director for the North Met mining project in Minnesota being developed by Poly Met Mining Corp. Leanne Hall Director Prior to joining Des Nedhe in 2019 as CEO of Creative Fire, Leanne was the National Leader of the Deloitte Indigenous practice, serving over 275 Indigenous communities across Canada. Her experience in business leadership and ability to build relationships between corporate partners and Indigenous business are integral to growth for our clients and our company. She has served as a director for the Canadian Council for Aboriginal Business and is a member of the Board of Governors for Wilfrid Laurier University and is a WXN Top 100 Most Powerful Women in Canada Award Winner. TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 36#38MANAGEMENT TEAM Dan Wilton CEO & Director G FIRST MINING GOLD Dan Wilton has 25 years of experience in M&A, corporate finance and principal investing in the mining sector. He was most recently a Partner at Pacific Road Capital Management, a mining-focused private equity investment firm with approximately $800 million under management. His prior role includes Managing Director and Head of the Global Mining and Metals Group at National Bank Financial Inc. Lisa Peterson CFO & Corporate Secretary Steve Lines VP, Sustainability James Maxwell VP, Exploration & Project Operations Lisa Peterson has over 14 years' experience within the mining, renewable energy, infrastructure, and professional services industries. Her most recent positions include serving as Chief Financial Officer of Libero Copper & Gold Corporation and other TSX-V junior listed Companies. Lisa previously held the role of Vice- President of Corporate Reporting & Global Accounting at SkyPower Global, a large-scale, international, renewable energy developer, and provider. Lisa also held roles at Barrick and KGHM. She started her career at KPMG. She is a Chartered Professional Accountant (CPA, CA) and holds a Bachelor of Business Administration degree from Simon Fraser University. Steve has over 19 years of professional practice in environmental assessment, permitting, Indigenous and community affairs on major mining projects. Most recently he led the Hardrock Gold Project Environment Assessment for Greenstone Gold Mines successfully obtaining approvals and permits from the federal and provincial governments and working in partnership with Indigenous communities to implement benefit agreements. Steve has also held positions with De Beers, Fortune Minerals and Lupin Mines. James is a professional geoscientist with over 20 years of industry experience with a focus on exploration and development of orogenic gold discoveries. James has a history working in the Birch-Uchi and Red Lake Greenstone belts where his team earned a Northwestern Ontario Prospectors Association Discovery of the Year Award for the Rahill-Bonanza discovery. James holds a Bachelor of Science from the University of Manitoba with a focus on geological sciences and is registered with the PGO in Ontario and the NAPEG in the NWT and Nunavut. Richard Huang VP, Corporate Development Richard has over 15 years of corporate finance, M&A and capital markets experience in the mining and resource sector, and has extensive experience providing strategic advice to large, mid and small cap mining clients on executing M&A and capital raising transactions. His previous experience includes mining sector coverage in the investment banking group at National Bank and equity capital markets group at Scotiabank. He holds a Bachelor of Business Administration (Distinction) from the Schulich School of Business at York University in Toronto. TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 37#39TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com APPENDIX G FIRST MINING GOLD | 38#40SPRINGPOLE GOLD PROJECT | 39#41COMPARABLE CANADIAN OPEN PIT DEVELOPMENTS FIRST MINING GOLD Conceptual Mine Site Plan Springpole Meadowbank Gahcho Kué Attribute Springpole Meadowbank Gahcho Kué Permanent Lake Loss (ha) 23 149 159 Altered Habitat (ha) 60 91 84 Disrupted Habitat (ha) 109 254 429 Total (ha) 192 494 672 % of Host Lake Affected Springpole (6%) 3%, 36%, >70% Kennedy (20%) Note: Values are approximate based on public information TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com G FIRST MINING GOLD | 40#42COMBINED FIRST MINING & WOOD EA EXPERIENCE First Mining has consolidated the EA process under WSP, a global environmental consultation firm responsible for permitting most of the major mining projects in Ontario Completed CEAA Projects Echo Bay 2000 Porcupine Joint Venture 2005 Victor Diamond Mine 2005 Detour Lake Mine 2012 Completed CEAA 2012 Projects Goliath Project 2019 + Côté Project 2019 Magino Project 2019 Hardrock Project 2018 Rainy River Mine 2015 Ongoing CEAA 2012 and IAA Projects Upper Beaver Project Springpole Project TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com MANITOBA ONTARIO QUEBEC G NORTH AKOTA MINNESOTA Ottawa Montreal SOUTH AKOTA MAIN WISCONSIN Toronto VT MICHIGAN NH NEW YORK Chicago MA IOWA JERDASKA CT RI FIRST MINING GOLD | 41#43MINES D'OR DUPARQUET#44DUPARQUET EXPLORATION STRATEGY Foundational Modernization and Geoscience Ownership • • Data centralization and validation for completeness, confidence and leverage Foundation lithology, structure and alteration models (phase I complete) Mineralisation controls and paragenesis outline Validation, Optimization and Extension of Data and Resources Diamond drilling targeting higher grade and forward mine life opportunities including; inferred resources, under resolved areas proposed for development, and expansion of the exploration space Expansion & Discovery • • Field data gap analysis and target expansion/screening Diamond drilling of near resource exploration opportunities seeking to identify areas of significant ounce potential Exploring large scale opportunity to unlock new discovery zone with significant strike/down plunge extent through field campaigns and diamond drilling TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com G FIRST MINING GOLD EXPLORATION TARGETING STRATEGIES FOR MEANINGFUL GROWTH Expansion & Discovery Validation, Optimization & Extension Foundational Modernization PDFZ & ownership | 43#45DUPARQUET EXPLORATION HIGHLIGHTS BUZZ ZONE DUP23-001 200 400 m Section Looking North Legend Gold Mineralization > 0.3 g/t Historical Gold Mineralization > 0.3 g/t Open Pit Design Drill Trace 2023 Historical Drill Trace Resource Wireframe Resource Expansion Opportunity Central Duparquet DUP23-003 2.53 g/t Au over 34.7 m 6.52 g/t Au over 4.6 m and 1.19 g/t over 10.4 m 3m @ 1.82 g/t Au DUP23-002 400m DUP23-003 DUP23-006 2.06 g/t Au over 26 m 2.16 g/t Au over 1.5m 2.5m @ 2.07 g/t Au Dumico 175m 8.9m @ 1.71 g/t Au 2m @ 2.57 g/t Au Drilling highlights: "Buzz Zone" 6.52g/t Au over 4.6m • Confirmation of a new gold zone G FIRST MINING GOLD Consolidation targets between the First Mining/IAMGOLD property boundary Targeting new zone potential based on strong historic endowment; large scale opportunity to unlock new zone with significant strike/down plunge extent Drilling highlights: Central Duparquet Targets • • N . . Exploration Between Central Duparquet and Dumico Resource Areas Returns 1.71 g/t Au over 8.9 m, Confirming Strike Continuity at “Valentre Target”; Central Duparquet High Grade Zone (CDHG Zone) Returns 2.73 g/t Au over 6.15 m, Unlocking Mineralization Potential at Depth A new area of mineralization continuity was identified at Central Duparquet These results validate the resource wireframe and support the extension of a higher- grade zone with mineralization continuity at depth. Link to news releases Grade Hole ID From (m) To (m) Length (m) Target (Au g/t) DUP23-002 DUP23-003 450.8 455.4 4.6 6.52 Buzz 659 660 1 4.94 Buzz DUP23-005 292 296 4 1.78 CDHG Zone DUP23-005 306 312.15 6.15 2.73 CDHG Zone DUP23-006 304.6 313.5 8.9 1.71 Valentre Target DUP23-006 353.9 355.9 2 2.57 Valentre Target DUP23-006 363.8 371.4 7.6 1.29 Valentre Target CDHG Zone DUP23-007 115 119.5 4.5 1.34 Extension Plunge +73 DUP23-008 235 238 3 2.04 CDHG Zone Azimuth 002 50 100 150 200 DUP23-008 243 254 11 2.83 CDHG Zone CENTRAL DUPARQUET TARGETS 7.6m @ 1.29 g/t Au TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 44#46Source: Google Maps PROJECT LOCATION Tailings Tailings Glory Hole Beattie Mine Lac Duparquet Image 2019 DigitalGlobe Go *2018 Google TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com 5340000 5350000 5360000 5370000 5380000 610000 620000 630000 Abitibi-Oues Property Name Duparquet Porcupine East Duquesne Pitt Historical Mine Route du Mont-c Amtfield Rapide- Danseur 640000 Duparquet Gold Project 650000 660000 101 arquet Rue de la Sarre Pestor Duquesne Abitibi-Ouest Rouyn-Noranda Town of Duparquet Pitt Gold 101 Rideau Evain D'Alembert 101 Rouyn-Noranda Rouyn-Noranda Avenue Larivière McWatters G FIRST MINING GOLD Abitibi-Ouest Rouyn-Noranda 670000 Clericy Mont-Brun Airport 0 Kilometres 20 5340000 | 45 N A 5350000 5360000 5370000 5380000#47PROJECT HISTORY Gold discovered in the 1930s 1933 1956: Construction of a roaster and gold production 1956: Mining operation ceases 1970s: Roaster is operational - used for custom roasting of Molybdenum concentrate 1980-2007: Limited exploration activity 2009-2013: Clifton Star options to acquire the property and earns into 10% ownership; +270,000 m of drilling completed during this time and project completed a PFS Property returned to owners in 2014 and placed under care and maintenance, where Clifton Star maintained a 10% ownership interest Clifton Star acquired by First Mining in 2016 September 2022 - Acquired 100% ownership of the project September 2023 - Announced results of a positive PEA on the Project TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com G FIRST MINING GOLD Cyanide Plant and Roaster 1934: Beattie Gold Mines is the largest gold producer in the province of Quebec • • Most of the mine buildings have been demolished and the shafts capped and allowed to naturally flood Only remaining buildings on the Beattie mine site are the roaster building, smoke stack and water tower | 46#48DUPARQUET PEA - SENSITIVITY ANALYSIS Gold Price Gold Price (US$/oz) $1,400 $1,600 $1,800 $2,000 $2,200 Pre-Tax NPV. 5% C$168 million C$621 million C$1.07 billion C$1.53 billion C$1.98 billion Pre-Tax IRR 8.5% 17.1% 24.9% 32.0% 38.6% After-Tax NPV 5% C$20 million C$310 million C$588 million C$859 million C$1.12 billion After-Tax IRR 5.5% 12.1% 18.0% 23.2% 28.0% Initial Capital Costs Operating Costs +20% +10% C$2.2 billion -10% -20% Pre-Tax NPV, Pre-Tax IRR After-Tax NPV 5% After-Tax IRR 5% C$814 million C$949 million C$1.07 billion C$1.18 billion C$1.28 billion 16.7% C$413million 20.4% 24.9% 30.5% 37.8% C$503 million C$588 million C$661 million C$723 million 12.0% 14.7% 18.0% 21.9% 26.9% Operating Costs Initial Capital Costs +20% +10% C$706 million -10% -20% Pre-Tax NPV 5% C$761 million C$917 million C$1.07 billion C$1.23 billion C$1.39 billion Pre-Tax IRR After-Tax NPV, 5% After-Tax IRR 19.5% $398million 14.0% 22.2% 24.9% 27.4% 29.9% $494 million C$588 million $680 million $771 million 16.0% 18.0% 19.9% 21.7% Note: Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com G FIRST MINING GOLD | 47#49DUPARQUET PEA PRODUCTION PROFILE - VS AISC + Average annual recovered gold production of 233 koz over 11-year mine life Opportunities to increase mine through resource expansion, feed from satellite deposits and regional milling LOM average annual AISC of less than US$1,000/oz Au Gold Production (koz) Duparquet PEA Production and Cost Profile G FIRST MINING GOLD 500 $1,284 $1,400 $1,200 $1,122 400 $1,055 $1,060 $1,000 $935 $934 $931 $874 $856 300 $764 $694 $800 $600 200 272 276 $400 255 223 236 238 223 231 211 217 100 186 $200 $0 0 1 2 3 4 5 UT 6 7 8 9 10 11 Production Year Note: Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com AISC (US$/oz) | 48#50DUPARQUET PEA CASH FLOW PROFILE Strong free cash flow generation at US$1,800/oz Au Over C$1.1 billion net free cash flow generated during LOM Cash Flow (C$M) $300 $200 $100 $0 ($100) ($200) Duparquet Cash Flow Profile G FIRST MINING GOLD $220 $203 $102 $114 $117 $152 $150 $167 $163 $184 $57 $85 ($99) ($490) ($300) ($400) ($500) -1 -2 1 2 3 4 5 6 7 8 9 10 11 12 Production Year Note: Further details can be found in the technical report titled "NI 43-101 Technical Report: Preliminary Economic Assessment, Duparquet Project, Quebec, Canada", dated October 20, 2023, as filed on SEDAR+ and on www.firstmininggold.com TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 49#51GREENSTONE GOLD MINES - HARDROCK PROJECT CASE STUDY Hardrock Project located in Geraldton, Ontario had very similar situation to the Duparquet Project Past producing mine ◉ ▪ Legacy arsenic issue ■ Deposit located near/in town, beside an important recreational lake Greenstone Gold Mines took the project through an Environmental Assessment from 2015 to 2019 G FIRST MINING GOLD ☐ Former Greenstone environmental team is currently working at First Mining Gold led by Steve Lines, VP Environment and Community Relations. Project construction began October 27, 2021 - $1.2 billion initial capital cost TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com Stantec Optimized Plan (Current as of May 2019) | 50#52OTHER ASSETS#53CAMERON GOLD PROJECT Excellent infrastructure with year-round highway access; camp, powerline within 20 km; 88 km from Rainy River mine Recent acquisition of East Cedartree claims consolidates strategic part of Cameron Gold Project and increases resource opportunity Acquisition adds over 32,200 hectares of prospective mineral tenure in the middle of the Cameron land package Exploration and drilling program currently being scoped Cameron NI 43-101 Resource* 430,000 mE Dogpaw McLennan Robertson Emm Bay Angel Hill Dubenski Syncline Anticline Syncline 440,000 mE East Cedartree FIRST MINING GOLD 450,000 mE 460,000 mE 470,000 mE N Shingwak Lake Anticline Monte Cristo Shear Zone Victor Monte Cristo Roy Jupiter Juno Hermione Sullivan Ajax Meston Cameron Shear Cameron Pipestone Cameron Fault 5,450,000 mN 5,460,000 mN 0 Kilometres 10 Resource Classification Constraint Au Cut- off (g/t) Tonnage Au Grade (g/t) Ounces Ontario Measured + Indicated Measured + Indicated Within $1,350 open-pit shell Below $1,350 open-pit shell 0.55 3,490,000 2.45 274,000 Kenora Timmins Thunder Bay Intermediate Felsic Volcanics Ottawa Mafic Volcanics 2.00 2,040,000 2.90 190,000 Map Extent Toronto Geology* Legend Mafic & Ultramafic Intrusives ☐ Felsic Intrusives Historical Development Gold Occurrence ☐ Cameron Gold Project Lake G FIRST MINING GOLD Cameron Gold Project Regional Geology Kenora Mining Division, Ontario Metasediments -Shear Zone Total M & I 5,530,000 2.61 464,000 *Ontario Geological Survey 2011: 1:250 000 scale bedrock geology of Ontario Miscellaneous Release Data 126- Revision 1 Projection: NAD83 Zone 15 Inferred Within $1,350 open-pit shell Below $1,350 0.55 35,000 2.45 3,000 Inferred Total Inferred 2.00 6,500,000 2.54 530,000 open-pit shell 6,535,000 2.54 January 2023 533,000 (*) See slide 25 for further details and disclosure, and refer to the technical report titled "Technical Report on the Cameron Gold Deposit, Ontario, Canada", dated effective January 17, 2017, which was prepared for First Mining by Optiro Pty Limited in accordance with NI 43-101, and which is available under First Mining's SEDAR+ profile at www.sedar.com. TSX: FF | OTCQX: FFMGF | FRANKFURT: FMG | www.firstmininggold.com | 52