SPRINGPOLE PROJECT, PROGRAM UPDATE 2020-09-16

First Mining Provides Update on its Springpole PFS,Environmental Permitting and Development Activities

VANCOUVER, BC / ACCESSWIRE / September 15, 2020 / First Mining Gold Corp. ("First Mining" or the "Company") (TSX: FF) (OTCQX: FFMGF) (FRANKFURT: FMG) is pleased to provide an update on the ongoing Pre-Feasibility Study ("PFS") on its Springpole Gold Project ("Springpole" or the "Project") located in northwestern Ontario, the federal and provincial environmental assessment processes and other ongoing or planned development and exploration activities.

"We are very optimistic and remain encouraged with the progress First Mining is making in advancing the Springpole gold deposit through PFS and through the environmental assessment processes" stated Dan Wilton, CEO of First Mining. "As we advance these critical de-risking steps for the Project, we are becoming increasingly aware of the value of the nine years of continuous environmental baseline data collection that we and our predecessors have completed at Springpole. We are very thankful for the dedication of our team and our partners to advance this important work in this uncertain environment. Our recent financing leaves First Mining in a very strong position to continue to move Springpole forward toward these critical de-risking milestones."

Pre-Feasibility Study Update

The PFS is being conducted by Ausenco Engineering Canada Inc. as Lead Consultant (see news release dated November 14, 2019). AGP Mining Consultants Inc. are acting as the overall QP and Mining Consultant, SRK Consulting (Canada) Inc. as the Resource Consultant, Knight Piesold Ltd. as the Tailings and Coffer Dam Consultant, Hemmera Envirotech Inc. and Wood PLC as Environmental Consultants, Nordmin Engineering Ltd. as the Power Infrastructure Consultant and Fracflow Consultants Inc. as the Geotechnical Consultant.

Throughout the PFS process, the Company has undertaken a number of key trade-off studies which are nearing completion. These studies have identified several important avenues to optimize the project scope, reduce the overall project footprint, mitigate environmental risks, and improve the economic robustness of the Project.

The October 2019 Preliminary Economic Assessment ("PEA") outlined a plan incorporating a design for a conventional tailings storage facility. A key trade-off study of the PFS assessed the feasibility of both thickened tailings and dry stack tailings solutions. Both were found to be viable solutions based on economic impacts, while significantly reducing the environmental risks and overall project footprint.

Mine plan optimization has been completed and is currently under review. Several iterations and varying combinations of pit shells, phasing, and haulage routes point to an opportunity for an improved mine plan from what was incorporated into the previous PEA. The optimization work has also demonstrated that there is more than enough suitable material that can be taken from the initial pre-strip and used for the full construction of the coffer dams.

The PFS metallurgical test program is also nearing completion. The process design in the PFS will incorporate conventional methods for recoveries but it is expected that further test programs during any subsequent feasibility study on Springpole will incorporate the study of potential value increases from the use of recent and significant industry advances in technology. Other key trade-off studies include the selection of a value-optimized processing rate/throughput for the mill and the selection of a safe and environmentally robust design and construction methodology for the coffer dams.

CAPEX and OPEX estimating are well underway with major equipment quotes being received for process, infrastructure, and mining. The PFS is on schedule for delivery in the first half of Q1 2021.

Environmental Assessment Update

Drilling to support the ongoing metallurgical, hydrogeological, and geotechnical programs has been completed, for a total of 5,700 metres ("m"). A 6,300 m condemnation drilling program has also recently commenced and is scheduled to be completed over the winter.

The Company's goal is to prepare a synchronized Environmental Impact Statement ("EIS") that meets the federal and provincial environmental assessment requirements. For the provincial process, there are two main stages, namely the development of the Terms of Reference ("ToR") and the development of the EA Report. First Mining submitted the ToR for Springpole to the Ministry of the Environment, Conservation and Parks ("MECP") on August 21, 2020, and it is available on the Company's website, www.firstmininggold.com.

First Mining recently engaged Wood PLC's Environment and Infrastructure Solutions group to support the preparation of the federal EIS and the provincial EA Report for the Project. Some recent examples of Wood's experience and success in this field include the permitting of several of the largest and most significant gold projects in Ontario, including Côte Gold, Rainy River Gold Mine, Detour Lake and Goliath.

Over the past year, the Company has made significant progress on collecting the data it needs to complete the EIS. This data collection exercise complements the nearly 10 years of continuous environmental baseline monitoring and study of the aquatic and terrestrial environment in the region of Springpole. Over the past year, the Company has initiated ARD/metal leaching testing of its tailings and waste rock, installed a climatic station, noise dosimeters and dust monitors, conducted biophysical baseline studies and, working with our Indigenous communities, initiated traditional knowledge and land use studies. Surface water quality monitoring has been well advanced and will continue as necessary to support the requirements for submission of the draft EIS in 2021.

Assessing Springpole's Ongoing Exploration Potential

The Company plans to undertake additional regional exploration at Springpole, initially focusing on its Satterly Lake property, which is located to the west of the Springpole deposit, and a small drill program of 4 to 6 drill holes is being planned for this area. This property has a favourable regional geological setting within the Birch-Uchi greenstone belt and proximity to the Swain Lake Deformation Zone. Exploration will focus on areas of anomalous gold mineralization along the contact and within the Green Camp porphyritic stock located in the northern part of the property, which has been previously identified by historical rock sampling, channel sampling and drilling. The gold mineralization in the northern part of the property is widespread with numerous mineralized zones. The most significant area to date is the Green Camp area, where the gold mineralization can be traced over a distance of 220 m x 75 m and to a vertical depth of 130 m, as defined by six historical drill holes. One historical drill hole (RB85-05) assayed 1.33 g/t Au over 132 m. The Green Camp is located approximately 12 kilometres southwest of the Springpole camp.

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 ("NI 43-101"), 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, currently hosting a mineral resource base of 4.67 million ounces of gold in the Indicated category and 0.23 million ounces of gold in the Inferred category1. A Pre-Feasibility Study is underway, with completion targeted in early 2021, and permitting is ongoing with submission of the Environmental Impact Statement targeted for 2021. The Company also holds a large equity position in Treasury Metals Inc. that is advancing the Goliath-Goldlund gold projects 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.), Cameron, Hope Brook, Duparquet, Duquesne, and Pitt gold projects.

First Mining was created 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