First Mining Gold Corp. announce the discovery of new gold occurrences confirmed from rock sampling assay results from its 2023 exploration program at its Birch-Uchi Greenstone Belt Project located near its Springpole Gold Project in northwestern Ontario, Canada. Exploration assay results have identified a new near-surface and high priority structural setting for gold mineralization approximately 375 metres from the recently 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. The Challenger target and recently tested Saddle target are located approximately 12 km southwest of Springpole. Challenger Target Highlights: Two newly discovered gold mineralization occurrences within 60 m of each other, with samples grading up to 25.60 g/t Au.

Close proximity to an expanding gold mineralization system (375 m NW of Saddle) identified in First Mining's 2023 winter drill program, where Saddle drilling returned 0.92 g/t Au over 114 m. Employed geoscience systems approach to characterize the arget geology, supporting additional exploration opportunities in close proximity to the Challenger and Saddle target areas. BUGB Project is proving to be prospective with increasingly advanced and catalogued targets providing for future resource potential. The Challenger target is located approximately 12 km southwest of First Mining's Springpole Gold Project, which hosts a NI 43-101 mineral resource totalling 4.6 million ounces of including grab samples at Rice (7.54 g/t and 2.67 g/t), Green (1.79 g/t), and Exit and Trench Grid (4.8 g/t), that form a notable trend with the Saddle and Challenger target areas over a projected 1 km strike length.

Opportunities for expanding the mineralization system and the potential for exploring within a related structural setting have elevated the regional prospectivity in advancing the area. Exploration completed in First results which vector towards a mineralization setting that includes several structures surrounding and proximal to an intrusive centre, with higher-grade grab samples found proximal to the contact of the sedimentary host rock and the felsic intrusive unit. In 2022, the Company conducted additional airborne geophysical surveying that supported improved targeting resolution for exploration drilling.

Through processing and interpretation, modelled shear zone(s) coincident with mineralization have been interpreted which has proved to be valuable in step-out exploration planning. During the 2023 winter program, First Mining successfully completed 842 m of drilling in 5 exploration drill holes focused on the Saddle target. Drilling was aimed at validating the newly developed 3D exploration model, underpinned by historical drilling and field-based data collection, as well as testing extensions along strike, at depth, and across an interpreted fault offset.

The results from the 2023 winter drilling highlight robust intervals of consistent gold mineralization over significant widths including 0.92 g/t Au over 114 m and 0.75 g/t Au over 57.70 m (drill hole SAT23-001). The program has been successful in confirming the continuation of the mineralization envelope along the shear structure, opening up the exploration growth potential around the Saddle target which continues to demonstrate an evolving gold mineralization setting with advancing exploration. The 2023 summer field campaign for the Saddle area followed up on key geological features with a specific focus on geochemistry and geophysical signatures which have been interpreted to be related to Saddle gold mineralization.

First Mining's exploration teams this year completed regional infill mapping transects and conducted prospecting in previously underexplored areas. Through mapping and prospecting, 56 grab samples were taken across the area, of which 18 grab samples were taken in the Challenger target area, 46 outcrop stations were mapped, and 51 regional soil samples were collected. Results of the Saddle target follow-up exploration program confirmed surface mineralization, shear structures and an alteration low trend which occurred proximal to an area of anomalous gold in historical soil samples (100 ppb Au).

Investigation of the geoscience components led to the new discovery. Initial assay results for samples from the Challenger target discovery returned 25.6 g/t Au and 4.42 g/t Au in rock grab assays along a regional transect, prompting further in-field mapping and sampling to better characterize and validate the relationship between mineralization, alteration and the resistivity low extending along trend. Assay results from the follow-up campaign further validated this signature at the Challenger target and established a 60 m strike extension between a 25.6 g/t Au and 7.1 g/t Au rock grab sample.

On a regional scale, the Challenger as well as the Rice and Saddle targets are supportive of two favourable resistivity low expressions that average up to ~100 m in width, have a ~600 m estimated strike length and form a positive vector for follow-up exploration programs. First Mining's BUGB Project hosts significant district-scale exploration leverage in forming part of a consolidated >70,000 hectare mineral tenure. The property and broader greenstone belt hosts historic production centres that are demonstrative of the strong gold endowment and an affinity for potential new discovery. First Mining's extensive BUGB property position is located within the Red Lake Mining District and is situated approximately 80 km east of the Red Lake Mines Complex of Evolution Mining, and 75 km northeast of Kinross Gold's Dixie Project.

Geology of the region is comprised of Archean Greenstone terranes that are endowed by significant gold mineralization inclusive of orogenic and alkaline intrusion-related deposit styles. Initial data compilation and validation to date has indicated that the region demonstrates an underexplored and previously fragmented exploration immaturity that is well levered to the Company's strategy of consolidation and district screening.