October 28, 2020 TSX.V – GIGA Giga Metals Corporation Announces Results of a Comprehensive Preliminary Economic Assessment (“PEA”) for the Production of High- grade Nickel Concentrate from the Turnagain Nickel Deposit Vancouver, B.C. – Giga Metals Corp. (TSX VENTURE: GIGA) ( “Giga Metals” or the “Company”) today announced the results of a preliminary economic assessment (“PEA”) prepared in accordance with National Instrument 43-101 (“NI 43-101”) for the Turnagain Nickel-Cobalt Project (“Turnagain”) located 65 km east of Dease Lake in British Columbia, Canada. The PEA is an update of the 2011 PEA confirming the ability of Turnagain to produce high-quality nickel concentrate, such as that needed to make pure nickel products for the electric vehicle (EV) market, in a socially and environmentally responsible manner. The PEA has been prepared by Hatch Ltd, a global engineering company with substantial expertise in the mining sector, with input from Hatch personnel and industry expert consultants including Wood Mackenzie (nickel and cobalt markets, smelter terms), Blue Coast Metallurgy (process design), Knight Piésold (tailings and water management), Kerr Wood Leidal (power supply and costs), and Kirkham Geosystems (resource model and estimates). Giga Metals’ primary driver for this update was to deliver a reliable and comprehensive PEA incorporating all project- related components for use for discussion with strategic investors, for targeting improvement opportunities, and to serve as a base for future engineering studies. Summary The PEA indicates a long-life, large-scale project. With a projected build capital of US$1.4B (Phase 1) and US$0.5B (Phase 2) including significant investment for a powerline delivering low-cost, clean, low-carbon power from BC Hydro (mainly hydroelectric), the projected capital intensity is US$51,500 per annual tonne nickel at full rates (years 6 to 20). At full rate (years 6 to 20), the project is expected to deliver 37,149 tonnes per year of nickel in a high-grade nickel concentrate at an operating cost of US$3.20/lb nickel before by-product credits at the plant gate (all production data are metal in produced concentrate), or US$3.04/lb nickel after credits and shipping (in concentrate, delivered CIF Asia port). At metals prices of U.S. $7.50 per pound of nickel and smelter terms of 78% NSR as provided by Wood Mackenzie, Turnagain is expected to have a pre-tax IRR of 6.3%. At the environmental, social, and governance (ESG)-premium pricing1 case, the project is expected to have a pre-tax IRR of 9.4%. The base case pricing is based on a 1 The ESG premium case is based on an anticipated premium for nickel produced with low carbon emissions and in accordance with best practices relating to tailings management, environmental regulation and practice, treatment of workers and communities, and governance practices, as desired by customers who are looking to position themselves as sustainable producers. 1 relatively conservative EV demand forecast creating a nickel shortfall after 2030 growing to 1.3 Mt/y by 2040. This projected deficit requires more than 35 Turnagain-scale projects to fill. Based on the resources previously disclosed (Sep 19, 2019) including 1.07 billion tonnes of Measured and Indicated and 1.1 billion tonnes of Inferred (respectively, 5.2 billion pounds and 5.5 billion pounds of nickel content), the project is expected to operate for at least 35 years, producing 1.2 million tonnes of nickel-in-concentrate at an average grade of 18% nickel and 1% cobalt, comparable to the best nickel concentrates currently produced in the world. At this stage, the PEA does not include valuation of potentially significant opportunities identified such as carbon sequestration from the waste residue (tailings) to be deposited in the Tailings Management Facility (TMF). The Company is actively working on quantifying carbon dioxide (CO2) sequestration rates through independent scientific research currently ongoing at the University of British Columbia by Dr. Greg Dipple. Giga Metals is targeting to minimize the greenhouse gas (GHG) footprint of the Turnagain mine once operational and CO2 sequestration by the TMF is expected to help achieve the goal of CO2 neutrality in future years. Turnagain PEA Overview The PEA was prepared by Hatch Ltd, a global engineering company with substantial expertise in the mining and metals sectors, with input from industry expert consultants including Kirkham Geosystems (resource model and estimates), Blue Coast Metallurgy (process design), Knight Piésold (tailings and water management), Kerr Wood Leidal (power supply and costs), and Wood Mackenzie (nickel and cobalt markets, smelter terms). For more details, see the Qualified Persons section below. The PEA is preliminary in nature, 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, as such, there is no certainty that the PEA results will be realized. Highlights (all currencies are reported in US dollars): • Notable ESG credentials o Production of nickel in concentrate at a very low GHG intensity of <2.5 t CO2e/t Ni (base case – diesel haul fleet), with potential reduction to <1 t CO2e/t Ni with the use of electrified haul equipment when it becomes available o Efficient tailings storage potential in sub-aerial valley impoundment, allowing natural sequestration of CO2 through mineral carbonation o Excellent water balance, operates in a near-neutral water balance for most of the mine life o Located in well-regulated developed jurisdiction that has adopted First Nations’ rights to informed consent into permitting processes • Production of clean, high-grade nickel sulphide concentrate (18% nickel, 1% cobalt) with no impurities at deleterious levels 2 • Competitive costing with large greenfield nickel development o Capital cost for Phase 1 of US$1.4B inclusive of construction and owners costs, comprised of US$1.1B plus power line construction at US$0.3B, with expansion in Year 6 at US$0.5B, taking production to 37 kt/y Ni o Life-of-mine operating cost at US$2.81/lb Ni delivered to plant gate, net of by-product credits • Industry standard processing with current smelting and refining charges delivers pre-tax IRR of 6.3% at base case pricing of US$7.50/lb Ni and 9.4% at ESG- premium pricing case of US$8.50/lb Ni PEA Assumptions and Economic Results The PEA is based on a set of assumptions and calculated results. The major values are indicated in the table below. Average values are annual or weight-averaged by mill feed or nickel production, as appropriate. All costs are presented in US$. Site operating costs including all direct operating costs and G&A. Net operating costs below are inclusive of transport to port (assumed Asia) and expected net payment for contained cobalt. Construction capital costs include off-site infrastructure (high-voltage power line for connection to existing provincial power supply grid, access road). Sustaining capital costs include allowances for ongoing TMF development, mining equipment, plant capital equipment replacement, closure related costs, and costs for access to the BC Northwest Transmission Line (for clean low-carbon power supply). All costs are estimated using an exchange rate of C$1.30 = US$1.00. Phase 1 Phase 2 Phase 2 LOM LOM All parameters annual average except capital (Y1-5) (Y6-20) (Y21-37) (Y1-37) (Y1-37) and sustaining capital cost Average Average Average Average Total Ore Processed (Mt) 15.3 32.7 32.6 30.3 1,122 Nickel Grade (%) 0.260 0.220 0.216 0.221 -- Nickel Recovery (%) 57.3 51.6 46.5 49.6 -- Nickel Production (t in concentrate) 22,754 37,149 32,821 33,215 1,228,961 Cobalt Production (t in concentrate) 1,379 2,224 1,902 1,962 72,592 Nickel Price ($/lb) and Payability $7.50 / 78% Cobalt Price ($/lb) and Payability $22.30 / 35% Revenue ($M) $317 $517 $456 $462 $17,099 Site Operating Cost $8,852 ($/t ore) $9.63 $7.99 $7.56 $7.89 -- ($/lb Ni) $2.93 $3.20 $3.41 $3.27 -- Net Operating Cost ($/lb Ni) $2.77 $3.04 $3.27 $3.12 -- Capital Cost (construction, $M)** $1,381 $532 $1,913 Sustaining Capital ($M), $274 $1,011 $715* $2,000 including closure obligations** * Includes $2.8M in TMF and closure costs in Year 38 ** Total, not average Sensitivity Analysis The economic analysis for the project with a variety of primary sensitivities is shown in the table below. All values are pre-tax, in US$. 3 Parameter Value NPV (8%, $M) Pre-tax IRR Base Case (269) 6.3% ESG Incentive Price $8.50/lb Ni 242 9.4% Phase 1 Capital Costs (+/-20%) $1,657 / $1,104 (507) / (31) 5.2% / 7.8% Phase 2 Capital Costs (+/ -20%) $639 / $426 (330) / (208) 6.0% / 6.7% Sustaining Capital Costs (+/-20%) (379) / (159) 5.6% / 7.0% Site Operating Cost (+/-20%)* $3.92 / $2.61/lb Ni (694) / 156 3.2 % / 8.9% Nickel Payment 70% / 75% (663) / (417) 3.5% /5.3% Exchange Rate $0.70 / $0.80 39 / (408) 8.2% / 5.5% *factor applied across all years; LOM value shown for parameter value Revenues Revenues are based on a market study completed by Wood Mackenzie (WM). WM forecasts a significant nickel deficit beginning 2029, particularly for Class 1 nickel for EV/ESS battery uses. The total nickel market demand growth is estimated to require 133 kt/y of new supply by 2030 and 1,300 kt/y by 2040. This demand growth requires nickel producers to bring on an additional capacity in the 2030-2040 timeframe greater than three Turnagain projects every year.