Mr. John McCluskey reports

ALAMOS GOLD INTERSECTS ADDITIONAL HIGH-GRADE MINERALIZATION NEAR EXISTING INFRASTRUCTURE AT ISLAND GOLD WHICH IS EXPECTED TO DRIVE FURTHER GROWTH IN MINERAL RESERVES AND RESOURCES

Alamos Gold Inc. has released new results from underground exploration drilling at the Island Gold mine. Underground exploration drilling continues to extend high-grade gold mineralization across the Island Gold deposit within the main E1E and C zones, as well as several hangingwall and footwall structures in proximity to existing underground infrastructure. These results are expected to contribute to another increase in high-grade mineral reserves and resources at Island Gold to be outlined in the year-end 2023 update to be released later this month.

Island Gold Main zone exploration highlights: High-grade mineralization extended outside of mineral reserves and resources in the E1E and C zones; these zones are the main structures which host the majority of currently defined mineral reserves and resources at Island Gold. New highlights include:

• Island East (E1E zone):
  • 34.48 grams per tonne gold (34.48 g/t cut) over 2.82 metres (840-632-49);
  • 20.85 g/t Au (20.85 g/t cut) over 2.41 m (1040-619-20);
  • 19.22 g/t Au (19.22 g/t cut) over 2.05 m (945-624-34);
  • 16.13 g/t Au (16.13 g/t cut) over 2.45 m (840-530-09).
• Island West (C zone):
  • 106.04 g/t Au (48.86 g/t cut) over 2.38 m (490-456-13);
  • 19.56 g/t Au (19.56 g/t cut) over 3.81 m (790-479-40).

Island Gold hangingwall and footwall exploration highlights: High-grade gold mineralization intersected within several recently defined hangingwall and footwall zones across the main Island Gold deposit; these zones represent a significant opportunity to add near-mine mineral reserves and resources, which would be low cost to develop and produce given their proximity to existing infrastructure; this includes the NS1 zone, which was discovered early in 2023 and was being developed and mined by the end of the year. New highlights include:

• Island West hangingwall zones:

B zone:

• 29.33 g/t Au (23.89 g/t cut) over 6.93 m (790-479-34);
• 40.36 g/t Au (40.36 g/t cut) over 3.91 m (790-479-40);
• 65.23 g/t Au (24.36 g/t cut) over 2.28 m (900-506-09).

NS1 zone: Currently defined over a north-south strike of approximately 70 m and vertical continuity of over 450 m, and remains open up and downdip:

• 23.34 g/t Au (12.56 g/t cut) over 4.03 m (900-506-10);
• 17.30 g/t Au (8.61 g/t cut) over 3.41 m (900-506-11A);
• 12.33 g/t Au (12.33 g/t cut) over 3.96 m (900-506-07);
• 10.46 g/t Au (10.46 g/t cut) over 4.17 m (900-506-08).

• Island East footwall zones:

E1D1 zone:

• 67.08 g/t Au (13.21 g/t cut) over 2.56 m (1040-619-22);
• 50.10 g/t Au (12.67 g/t cut) over 2.35 m (1040-619-31);
• 14.78 g/t Au (14.39 g/t cut) over 2.17 m (1040-619-20).

E1D zone:

• 228.50 g/t Au (70.63 g/t cut) over 2.79 m (945-624-31A);
• 52.31 g/t Au (15.13 g/t cut) over 2.06 m (945-624-32).

Other hangingwall and footwall intersections: Drilling continues to intersect high-grade mineralization in proximity to existing underground infrastructure in yet-to-be-defined zones. These are part of more than 2,000 intersections above three g/t Au outside of existing mineral reserves and resources in the hangingwall and footwall, highlighting the opportunity for significant near-mine additions as continuing drilling further defines these areas. New highlights include:

Footwall:

• 1,389.65 g/t Au over 2.90 m (620-595-02);
• 39.42 g/t Au over 2.45 m (840-632-49);
• 25.85 g/t Au over 3.65 m (840-632-41);
• 18.71 g/t Au over 3.45 m (1015-640-06);
• 16.05 g/t Au over 2.75 m (840-632-41).

Hangingwall:

• 103.37 g/t Au over 2.90 m (900-506-13);
• 52.65 g/t Au over 2.15 m (900-506-06);
• 17.33 g/t Au over 2.70 m (900-506-13).

"Our transition to underground exploration drilling from surface directional drilling has been successful across a number of fronts. Drilling continues to extend high-grade mineralization across the two-kilometre-long lateral extent of the main Island Gold deposit, as well as within a number of new and expanding zones in the hangingwall and footwall. These results within the main Island Gold structure and a growing number of hangingwall and footwall zones are expected to drive another increase in combined mineral reserves and resources at Island Gold, with the year-end update to be released later this month. This is expected to mark the eighth-consecutive year of mineral reserve and resource growth, over which time the deposit has more than tripled in size to well over five million ounces of gold," said John A. McCluskey, president and chief executive officer.

"These expected high-grade additions are all in proximity to our existing underground infrastructure such that they will be low cost to develop and provide increasing operational flexibility as we expand the operation. With the main deposit open laterally and down plunge and more than 2,000 intersections of significant gold mineralization outside of existing reserves and resources in the hangingwall and footwall, we expect Island Gold's tremendous track record of growth to continue," Mr. McCluskey added.

2023 exploration drilling program -- Island Gold

During 2023, 157 holes totalling 39,110 metres were completed as part of the underground exploration program, and 155 holes totalling 31,636 m as part of the underground delineation drilling program. To support the underground program, a total of 404 m of underground exploration drift development was completed in 2023 on the 850, 945 and 1,025 levels. Additionally, 5,131 m of surface drilling was completed in three holes. The regional surface drilling program, focused on the Pine-Breccia and Cline Edwards Plowman targets, was completed in the third quarter of 2023 and included 42 holes over 8,432 m.

2024 exploration drilling program

A total of $19-million is budgeted for exploration at Island Gold in 2024, up from $14-million in 2023, with both a larger near-mine and regional exploration program planned for the year. The 2024 exploration program will follow up on a successful 2023 program with high-grade gold mineralization extended laterally to the west and east, as well as within multiple structures within the hangingwall and footwall.

Consistent with the 2023 program, the majority of the 2024 mine exploration program will be composed of underground drilling with 41,000 m planned. The focus will be the definition of new mineral reserves and resources in proximity to existing production horizons and infrastructure, as well as the conversion of the large existing mineral resource base to mineral reserves. This includes drilling across the strike extent of the main Island Gold deposit (E1E and C zones), as well as within a growing number of newly defined hangingwall and footwall zones. To support the underground exploration drilling program, 460 m of underground exploration drift development is planned to extend drill platforms on the 850, 945 and 1,025 levels.

Additionally, 12,500 m of surface exploration drilling has been budgeted, targeting high-potential areas within the Island West, Main and East ore shoots and the up plunge extension of the Island West ore shoot, and evaluating the potential for high-grade mineralized hangingwall structures near surface.

The regional exploration program has also been expanded to 10,000 m. The 2024 program will follow up on high-grade mineralization intersected at the Pine-Breccia and 88-60 targets, located four kilometres and seven kilometres, respectively, from the Island Gold mine. Drilling will also be completed in proximity to the past-producing Cline and Edwards mines, as well as at the Island Gold North shear target. A comprehensive data compilation project will also commence across the broader 40,000-hectare Manitou land package that was acquired in 2023 in support of future exploration targeting.

Island West

Underground exploration drilling

Underground drilling has further extended high-grade gold mineralization along strike, 150 m to the west, and up plunge of existing mineral reserves and resources in the middle portion of Island West. Drilling is being conducted from the 490-level and the 790-level exploration drifts, between vertical depths of 400 m and 1,100 m.

New highlights include:

C zone:

• 106.04 g/t Au (48.86 g/t cut) over 2.38 m (490-456-13);
• 19.56 g/t Au (19.56 g/t cut) over 3.81 m (790-479-40).

Island West hangingwall zones

In addition to testing the C zone, underground exploration drilling continued to target and expand on previous drilling that intersected high-grade gold mineralization in subparallel and perpendicular structures in the hangingwall from the 490, 790 and 900 levels.

NS1 hangingwall zone

The NS1 zone is a north-striking structure with a high-angle orientation relative to the C zone. After being discovered early in 2023, the first stopes were mined from the NS1 zone during the second half 2023, highlighting the near-term opportunities within these hangingwall and footwall zones. Continuing drill testing and five exploration sills have been completed from the 750, 770, 790, 810 and 850 levels, which have demonstrated excellent continuity, over an average strike of 40 m to the south on these levels, and over 100 m vertically. Additional drilling from the 490, 580, 770 and 900 levels has expanded the NS1 zone over a vertical extent of 450 m, from the 400 level to the 995 level, and defined an average strike of 70 m.

In addition to contributing to near-term production, an initial mineral reserve and resource will be declared within the NS1 zone in the year-end 2023 update. The zone remains open up and downdip, and will be a continuing focus of drilling in 2024. In addition, other north-striking high-angle structures have been identified across the deposit, which will be evaluated further as underground exploration drilling advances.

New highlights from the Island West hangingwall zones include:

B zone:

• 29.33 g/t Au (23.89 g/t cut) over 6.93 m (790-479-34);
• 40.36 g/t Au (40.36 g/t cut) over 3.91 m (790-479-40);
• 65.23 g/t Au (24.36 g/t cut) over 2.28 m (900-506-09).

NS1 zone:

• 23.34 g/t Au (12.56 g/t cut) over 4.03 m (900-506-10);
• 17.30 g/t Au (8.61 g/t cut) over 3.41 m (900-506-11A);
• 12.33 g/t Au (12.33 g/t cut) over 3.96 m (900-506-07);
• 10.46 g/t Au (10.46 g/t cut) over 4.17 m (900-506-08).

Island East

Underground exploration drilling

Underground drilling from the 840- and 945-level exploration drifts, as well as the 1,040 ramp, continues to extend high-grade gold mineralization along strike to the east of mineral reserves and resources in the middle portion of Island East (between vertical depths of 700 m and 1,300 m).

New highlights in the E1E zone include:

• 34.48 g/t Au (34.48 g/t cut) over 2.82 m (840-632-49);
• 20.85 g/t Au (20.85 g/t cut) over 2.41 m (1040-619-20);
• 19.22 g/t Au (19.22 g/t cut) over 2.05 m (945-624-34);
• 16.13 g/t Au (16.13 g/t cut) over 2.45 m (840-530-09);
• 16.99 g/t Au (16.99 g/t cut) over 2.05 m (840-632-47);
• 14.76 g/t Au (12.66 g/t cut) over 2.06 m (840-632-45).

Island East footwall zones

In addition to testing the E1E zone, underground exploration drilling continued to target and expand on previous drilling that intersected high-grade gold mineralization in structures in the footwall from the 945 and 1,040 levels. This additional drilling has been successful in establishing continuity and extending high-grade gold mineralization within multiple structures referred to as the E1D1 and E1D zones, located 10 m and 30 m from the E1E zone, respectively.

New highlights from the Island East footwall zones include:

E1D1 zone:

• 67.08 g/t Au (13.21 g/t cut) over 2.56 m (1040-619-22);
• 50.10 g/t Au (12.67 g/t cut) over 2.35 m (1040-619-31);
• 14.78 g/t Au (14.39 g/t cut) over 2.17 m (1040-619-20);
• 14.45 g/t Au (14.45 g/t cut) over 2.05 m (1040-619-13).

E1D zone:

• 228.50 g/t Au (70.63 g/t cut) over 2.79 m (945-624-31A);
• 52.31 g/t Au (15.13 g/t cut) over 2.06 m (945-624-32).

As with the hangingwall and footwall zones in Island West, these footwall zones in Island East highlight the potential to add high-grade mineral reserves and resources in proximity of existing production horizons and infrastructure, which would be low cost to develop and mine.

Other zones

The majority of Island Gold's mineral reserves and resources and main production horizons is hosted in the C/E1E structure. The Island Gold deposit also consists of a growing number of subparallel and high-angle mineralized structures outside of the main C/E1E zone. As underground development advances, these subparallel hangingwall and footwall structures can be targeted and defined with stepout drilling from underground drill platforms.

These zones and other targets within the hangingwall and footwall represent significant opportunities to define additional high-grade mineral reserves and resources outside of the main C/E1E-zone in proximity to existing underground infrastructure. These additions would enhance the ounce-per-vertical-metre profile and provide multiple mining horizons from the same lateral development levels.

The following are highlights of new hangingwall and footwall intersections from underground exploration drilling, where the geometry and continuity are not yet established. These are part of more than 2,000 intersections above three g/t Au within recently defined and yet-to-be-defined zones in the hangingwall and footwall. These intersections are outside of existing mineral reserves and resources, highlighting the opportunity for significant near-mine additions as continuing drilling further defines these areas.

New highlights include (reported composite intervals are uncut and as core length, as true width is unknown at this time):

Footwall intersections:

• 1389.65 g/t Au over 2.90 m (620-595-02);
• 39.42 g/t Au over 2.45 m (840-632-49);
• 25.85 g/t Au over 3.65 m (840-632-41);
• 18.71 g/t Au over 3.45 m (1015-640-06);
• 16.05 g/t Au over 2.75 m (840-632-41).

Hangingwall intersections:

• 103.37 g/t over 2.90 m (900-506-13);
• 52.65 g/t Au over 2.15 m (900-506-06);
• 17.33 g/t Au over 2.70 m (900-506-13).

Qualified persons

Scott R.G. Parsons, PGeo, FAusIMM, Alamos's vice-president, exploration, has reviewed and approved the scientific and technical information contained in this news release. Mr. Parsons is a qualified person as defined by Canadian Securities Administrators' National Instrument 43-101 (Standards of Disclosure for Mineral Projects).

Exploration programs at the Island Gold mine are directed and supervised by Tyler Poulin, PGeo, chief geologist at the Island Gold mine. Mr. Poulin is a qualified person as defined by Canadian Securities Administrators' National Instrument 43-101 (Standards of Disclosure for Mineral Projects).

Quality assurance and quality control

Alamos maintains an internal quality assurance/quality control program at the Island Gold mine to ensure sampling and analysis of all exploration work are conducted in accordance with best practices.

Access to the Island Gold mine is controlled by security personnel. Drill core is logged and sampled at core logging facilities within the mine site under the supervision of a qualified geologist. A geologist marks the individual samples for analysis, and sample intervals, sample numbers, standards and blanks are entered into the database. The core is cut in half using an electric core saw equipped with a diamond tipped blade. One-half of the core is placed into a plastic sample bag and sealed with zip ties in preparation for shipment. The other half of the core is returned to the core box and retained for future reference. The samples are placed in large heavy-duty nylon reinforced Fabrene bags, which are identified and sealed before being placed on pallets. The core samples are picked up at the mine site, and mine samples are delivered to Agat and Actlabs laboratories, and regional samples are delivered to ALS laboratory, all located in Thunder Bay, Ont.

Gold is analyzed by a 50-gram fire assay with an atomic absorption finish. Mine samples greater than 10.0 g/t Au and regional samples greater than 5.0 g/t Au are reanalyzed using gravimetric finish methods. Agat, Actlabs and ALS are certified laboratories, and have internal quality control programs that include insertion of reagent blanks, reference materials and pulp duplicates.

The corporation inserts QC samples (blanks and reference materials) at regular intervals to monitor laboratory performance. Cross-check assays are completed on a regular basis in a secondary accredited laboratory. The Island Gold mine QA/QC procedures are more completely described in the Aug. 29, 2022, technical report filed on SEDAR+.

About Alamos Gold Inc.

Alamos is a Canadian-based intermediate gold producer with diversified production from three operating mines in North America. This includes the Young-Davidson and Island Gold mines in Northern Ontario, Canada, and the Mulatos mine in Sonora state, Mexico. Additionally, the company has a strong portfolio of growth projects, including the phase 3-plus expansion at Island Gold, and the Lynn Lake project in Manitoba, Canada. Alamos employs more than 1,900 people and is committed to the highest standards of sustainable development. The company's shares are traded on the Toronto Stock Exchange and New York Stock Exchange under the symbol AGI.

All dollar amounts are in U.S. dollars unless otherwise stated.

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