Alamos Gold Extends High-Grade Gold Mineralization within Multiple Zones Across the Island Gold Deposit and Two Regional Exploration Targets

TORONTO, Nov. 09, 2023 - Alamos Gold Inc. (TSX:AGI; NYSE:AGI) ("Alamos" or the "Company") today reported new results from its near mine and regional exploration drilling program at Island Gold. 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 hanging wall and footwall structures in proximity to existing underground infrastructure. Additionally, the regional exploration program has been successful in intersecting high-grade gold mineralization at two early-stage targets.

Island Gold Mine - 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 include¹:

• Island East (E1E-Zone)
  • 95.41 g/t Au (30.42 g/t cut) over 3.02 m (840-578-26);
  • 118.59 g/t Au (61.74 g/t cut) over 2.31 m (1015-640-12);
  • 62.09 g/t Au (61.83 g/t cut) over 2.19 m (840-632-24); and
  • 37.33 g/t Au (33.16 g/t cut) over 2.56 m (840-608-52).

• Island West (C-Zone)
  • 40.12 g/t Au (40.12 g/t cut) over 2.02 m (790-479-29);
  • 17.23 g/t Au (17.23 g/t cut) over 3.02 m (790-479-22); and
  • 23.79 g/t Au (23.79 g/t cut) over 2.05 m (790-479-20).
    

Island Gold Mine - hanging wall and footwall zone exploration highlights: high-grade gold mineralization continues to be intersected within a number of new and recently defined hanging wall 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. New highlights include¹:

• Island East Footwall Zones

NTH4 Zone

• 168.03 g/t Au (27.88 g/t cut) over 3.14 m (840-632-21);
• 43.33 g/t Au (24.58 g/t cut) over 2.00 m (840-632-43);
• 25.94 g/t Au (13.92 g/t cut) over 3.14 m (840-632-32); and
• 19.55 g/t Au (11.36 g/t cut) over 2.03 m (840-632-25).

E1D1 Zone

• 47.62 g/t Au (20.19 g/t cut) over 2.78 m (945-624-15);
• 41.40 g/t Au (12.13 g/t cut) over 2.16 m (945-624-16);
• 22.12 g/t Au (6.17 g/t cut) over 3.77 m (945-624-28); and
• 17.32 g/t Au (11.84 g/t cut) over 3.81 m (945-624-19A).

E1D Zone

• 17.84 g/t Au (10.07 g/t cut) over 3.57 m (945-624-28); and
• 22.71 g/t Au (22.71 g/t cut) over 2.53 m (945-624-29).

• Island West Hanging Wall Zones: the NS1 zone has now been interpreted to have an average North-South strike of approximately 70 m, with vertical continuity of over 400 m and remains open up and down dip. This zone was not factored into the 2023 mine plan but is currently being developed and mined after being defined earlier this year. New highlights include¹:

• 121.37 g/t Au (15.47 g/t cut) over 2.65 m (770-475-01);
• 34.08 g/t Au (16.28 g/t cut) over 5.40 m (770-475-12);
• 23.46 g/t Au (10.16 g/t cut) over 2.14 m (770-475-14); and
• 21.89 g/t Au (8.45 g/t cut) over 2.20 m (770-475-13).

• Island West Footwall Zones (DN zone sub-parallel structure). New highlights include¹:

• 47.44 g/t Au (12.02 g/t cut) over 2.43 m (790-479-35);
• 13.97 g/t Au (13.78 g/t cut) over 2.59 m (790-479-33); and
• 13.78 g/t Au (13.78 g/t cut) over 2.48 m (790-479-36).
  

¹ All reported drill widths are true width of the mineralized zones, unless otherwise stated. Drillhole composite intervals reported as "cut" may include higher grade samples which have been cut to: C-zone @ 225 g/t Au; E1E Zone @ 185 g/t Au. B Zone @ 90 g/t Au; NS1 Zone @ 60 g/t Au; D1 and G1 Zones @ 45 g/t Au; G Zone @ 70 g/t Au; E1D @ 80g/t Au; DN, E1D1, NTH1, NTH2, NTH3, NTH4 @ 35 g/t Au.

Regional exploration highlights: high-grade mineralization intersected at two regional targets in proximity to the Island Gold operation. New highlights include²:

• Pine Zone: 4 kilometres ("km") northeast of the Island Gold Mine
  • 29.77 g/t Au over 9.31 m (23IGX057), including:
    • 59.15 g/t Au over 4.39 m, including:
      • 378.00 g/t Au over 0.37 m
  • 3441.64 g/t Au over 0.67 m (23IGX043), including:
    • 6220.00 g/t Au over 0.37 m

• 79.44 g/t Au over 4.06 m (23IGX053), including:
  • 932.00 g/t Au over 0.33 m
• 7.22 g/t Au over 7.45 m (23IGX055), including:
  • 11.87 g/t Au over 3.43 m
• 3.12 g/t Au over 9.64 m (23IGX059), including:
  • 20.10 g/t Au over 0.36 m

Adjacent Vein Arrays

• 6.44 g/t Au over 7.26 m (23IGX050), including:
  • 63.1 g/t Au over 0.52 m
• 17.67 g/t Au over 1.44 m (23IGX053), including:
  • 23.60 g/t Au over 1.05 m

• 88-60 Zone: 7 km from the Island Gold Mine, in proximity to the historic Cline and Edwards mines:

• 6.00 g/t Au over 11.18 m (23IGX066), including:
  • 19.79 g/t Au over 1.12 m
  • 20.90 g/t Au over 0.78 m
  • 24.60 g/t Au over 0.58 m
• 14.62 g/t Au over 1.5 m (23IGX066), including:
  • 21.80 g/t over 0.94 m;
• 6.19 g/t Au over 3.31 m (23IGX065), including:
  • 55.50 g/t over 0.34 m.
    

² Regional exploration drillhole composite intervals reported as uncut, composites lengths are reported as core length, true widths are estimated at 40 to 85% of core length. Composites are calculated with a 0.5 g/t cut-off, maximum internal waste of 4 m, and no minimum thickness. Higher-grade intervals within the primary drillhole composite are reported as "Including" for any individual or consecutive samples with assay grades greater than 10 g/t Au.

"We continue to see excellent results from our exploration program at Island Gold across multiple areas of focus. The transition from surface directional drilling to underground drilling this year has been a success as we leverage our existing underground infrastructure. We are extending high-grade mineralization across the lateral extent of the main Island Gold deposit while also defining and growing an increasing number of new zones within the hanging wall and footwall. Our success on both fronts demonstrates the significant potential for the addition of high-grade Mineral Reserves and Resources near our existing underground development. This is providing increasing operational flexibility and additional ounces that will be low-cost to develop, some of which are already being mined, highlighting the near-term opportunities," said John A. McCluskey, President and Chief Executive Officer.

"We are also very encouraged by the early results out of our regional exploration program with multiple high-grade intersections across the Pine and 88-60 targets. These early-stage targets are a good illustration of the excellent potential for additional high-grade deposits to be defined across our large 55,300 hectare land package, which we more than tripled in size earlier this year," Mr. McCluskey added.

New highlight intercepts can be found in Tables 1 and 2, and in Figures 1 to 3 at the end of this news release.

2023 Exploration Drilling Program - Island Gold Mine

A total of $14 million is budgeted for exploration at Island Gold in 2023. For the past several years, the exploration focus has been on adding high-grade Mineral Resources at depth, primarily through surface directional drilling. This exploration strategy has been successful in tripling the Mineral Reserve and Resource base since 2017. With a 17-year mine life, and with work on the Phase 3+ expansion ramping up, the focus has shifted to a more cost-effective expanded underground exploration drilling program that will leverage existing underground infrastructure. This drilling is much lower cost on a per metre basis, is less technically challenging, and requires significantly fewer metres per exploration target.

A total of 45,000 m of underground exploration drilling has been planned for 2023. The focus is on defining new Mineral Reserves and Resources in proximity to existing production horizons and infrastructure including along strike, and in the hanging-wall and footwall. These potential high-grade Mineral Reserve and Resource additions would be low cost to develop and could be incorporated into the mine plan and mined within the next several years, further increasing the value of the operation. To support the underground exploration drilling program, 444 m of underground exploration drift development is planned to extend drill platforms on the 490, 790, 945, and 980-levels. In addition to the exploration budget, 36,000 m of underground delineation drilling has been planned and included in sustaining capital for Island Gold.

A total of 32,459 m of underground exploration drilling, and 24,649 m of delineation drilling has been completed as of October 31, 2023. A regional exploration program including a total of 8,439 m of drilling was also completed in 2023. The focus of this program was on advancing exploration targets outside the Island Gold Deposit on the newly expanded 55,300-hectare Island Gold property, including the Pine-Breccia and 88-60 targets described below.

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 580-level and the 790-level exploration drifts, between vertical depths of 700 m and 1,100 m.

New highlights include (Figure 1, Table 1):

C-Zone

• 40.12 g/t Au (40.12 g/t cut) over 2.02 m (790-479-29);
• 17.23 g/t Au (17.23 g/t cut) over 3.02 m (790-479-22);
• 23.79 g/t Au (23.79 g/t cut) over 2.05 m (790-479-20); and
• 12.75 g/t Au (12.75 g/t cut) over 2.38 m (790-479-21).

Island West Hanging Wall 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 sub-parallel and perpendicular structures in the hanging wall from the 580, 770, 790, and 850-levels. Additional drilling has been successful in establishing continuity and extending high-grade gold mineralization within multiple structures referred to as the B, G, and G1 Zones (Table 1). These zones are located 20 m, 75 m, and 110 m south of the main C-Zone, respectively, highlighting the significant potential to add high-grade Mineral Reserves and Resources in proximity of existing production horizons and infrastructure. These potential high-grade Mineral Reserves and Resource additions could be incorporated into the mine plan within the next several years and would be low cost to develop, further increasing the value of the operation.

NS1 Hanging Wall Zone

The NS1 zone is a north-striking structure with a high-angle orientation relative to the C-Zone that was identified earlier in 2023. Ongoing 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 580, 770, and 900 levels has now expanded the NS1 zone over a vertical extent of 400 m, from the 890 level to the 400 level, and defined an average strike of 70 m.

The first stope was mined from the NS1 Zone late in the third quarter of 2023 with grades performing in line with annual guidance. The NS1 zone is beyond currently defined Mineral Reserves and Resources and outside of the 2023 mine plan demonstrating the significant near-mine opportunities to add additional high-grade production in the near term. 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 Hanging Wall zones include (Table 1):

NS1 Zone

• 121.37 g/t Au (15.47 g/t cut) over 2.65 m (770-475-01);
• 34.08 g/t Au (16.28 g/t cut) over 5.40 m (770-475-12);
• 23.46 g/t Au (10.16 g/t cut) over 2.14 m (770-475-14); and
• 21.89 g/t Au (8.45 g/t cut) over 2.20 m (770-475-13).

B-Zone

• 16.13 g/t Au (13.68 g/t cut) over 2.33 m (770-475-26).
  

G-Zone

• 15.34 g/t Au (13.60 g/t cut) over 1.99 m (580-473-28).
  

Island West Footwall Zone

Underground exploration drilling is also targeting and expanding on previous drilling that intersected high-grade gold mineralization within a sub-parallel structure in the footwall from the 790-level. Ongoing drilling has been successful in extending high-grade gold mineralization and establishing further continuity within the DN structure (Table 1). This zone is located 100 m north of the main C-Zone.

New highlights from the Island West Footwall DN zone include:

DN Zone

• 47.44 g/t Au (12.02 g/t cut) over 2.43 m (790-479-35);
• 13.97 g/t Au (13.78 g/t cut) over 2.59 m (790-479-33); and
• 13.78 g/t Au (13.78 g/t cut) over 2.48 m (790-479-36).
  

Island East

Underground Exploration Drilling

Underground drilling from the 620 and 840-level exploration drifts 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 500 m and 1,000 m).

New highlights in the E1E-Zone include (Figure 1, Table 1):

• 95.41 g/t Au (30.42 g/t cut) over 3.02 m (840-578-26);
• 118.59 g/t Au (61.74 g/t cut) over 2.31 m (1015-640-12);
• 62.09 g/t Au (61.83 g/t cut) over 2.19 m (840-632-24);
• 37.33 g/t Au (33.16 g/t cut) over 2.56 m (840-608-52);
• 5.30 g/t Au (5.30 g/t cut) over 7.08 m (1015-624-08);
• 11.80 g/t Au (11.80 g/t cut) over 2.85 m (840-632-31); and
• 14.22 g/t Au (14.22 g/t cut) over 2.30 m (840-608-43B).
  

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 620 and 840-levels. This additional drilling has been successful in establishing continuity and extending high-grade gold mineralization within multiple structures referred to as the NTH, NTH2, NTH3, NTH4, E1D, and E1D1 zones.

The NTH zones are located 60 to 110 m north of the main E1E-Zone, and the E1D1 and E1D zones, 10 m and 30 m from the E1E-Zone, respectively.

New highlights from the Island East Footwall zones include (Table 1):

NTH4 Zone (Figure 2):

• 168.03 g/t Au (27.88 g/t cut) over 3.14 m (840-632-21);
• 43.33 g/t Au (24.58 g/t cut) over 2.00 m (840-632-43);
• 25.94 g/t Au (13.92 g/t cut) over 3.14 m (840-632-32);
• 28.80 g/t Au (7.92 g/t cut) over 2.48 m (840-632-33);
• 21.38 g/t Au (8.52 g/t cut) over 2.05 m (840-632-23);
• 16.34 g/t Au (11.35 g/t cut) over 2.44 m (840-632-24);
• 19.55 g/t Au (11.36 g/t cut) over 2.03 m (840-632-25); and
• 18.42 g/t Au (10.74 g/t cut) over 2.14 m (840-632-38).

NTH Zone

• 10.23 g/t Au (10.23 g/t cut) over 3.92 m (620-SIL-04).
  

E1D1 Zone

• 47.62 g/t Au (20.19 g/t cut) over 2.78 m (945-624-15);
• 41.40 g/t Au (12.13 g/t cut) over 2.16 m (945-624-16);
• 22.12 g/t Au (6.17 g/t cut) over 3.77 m (945-624-28);
• 17.32 g/t Au (11.84 g/t cut) over 3.81 m (945-624-19A); and
• 9.26 g/t Au (7.49 g/t cut) over 4.80 m (945-624-21).
  

E1D Zone

• 17.84 g/t Au (10.07 g/t cut) over 3.57 m (945-624-28); and
• 22.71 g/t Au (22.71 g/t cut) over 2.53 m (945-624-29).

As with the hanging 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 are hosted in the C/E1E structure. The Island Gold Deposit also consists of several sub-parallel and high-angle mineralized structures outside of the main C/E1E-Zone. As underground development advances, these sub-parallel hanging wall and footwall structures can be targeted and defined with step-out drilling from underground drill platforms.

This drilling allows for the confirmation of the geometry and potential continuity of mineralization with the objective of defining new Mineral Resources. As demonstrated with the E1D, E1ED1, NTH, NTH2, NTH3, NTH4 and perpendicular NS1 Zone, as well as the B, D, DN, G, and G1 Zones that were defined in 2022, a growing number of these zones are being defined as underground development is established in these areas.

These zones and other targets within the hanging wall and footwall represent significant opportunities to define additional Mineral Reserves and Resources outside of the main C/E1E-Zone in proximity to existing underground development. 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 hanging wall and footwall intersections from underground exploration drilling where the geometry and continuity is not yet established ("Unknown Zone") (reported composite intervals are uncut and as core length, true width is unknown at this time) (Table 1):

Footwall Intersections:

• 148.67 g/t Au over 2.00 m (790-479-35);
• 68.95 g/t Au over 2.93 m (945-624-19A);
• 33.86 g/t Au over 2.91 m (840-554-66);
• 37.57 g/t Au over 2.00 m (790-479-32);
• 26.31 g/t Au over 2.48 m (945-624-19A); and
• 30.25 g/t Au over 1.96 m (840-632-28).

Hanging Wall Intersections:

• 65.77 g/t Au over 2.00 m (580-473-39);
• 43.52 g/t Au over 2.84 m (770-475-28);
• 52.65 g/t Au over 2.00 m (900-506-06);
• 19.73 g/t Au over 3.73 m (945-624-20);
• 25.35 g/t Au over 2.66 m (770-475-22); and
• 17.21 g/t Au over 2.98 m (770-475-23).

Regional Exploration

The 2023 Regional Exploration program was successful in identifying high-grade gold mineralization at multiple early-stage targets, highlighting the significant regional potential across the 55,300 hectare Island Gold Property. A total of 8,439 m of regional exploration drilling has been completed to date in 2023. The priority drilling targets in 2023 included the Pine-Breccia, and 88-60 Zones, which are highlighted below.

Pine-Breccia Target (Figure 3)

Pine Zone

The Pine Zone is located approximately 4 km from the Island Gold Mine and comprises a sheared sulphide unit truncated by the regional NNW-trending Maskinonge Lake Fault that hosts the Breccia Zone (Figure 3). The sulphide unit was identified through a limited amount of historic drilling prior to Alamos' ownership. Follow up channel sampling completed by Alamos in 2022 confirmed and further defined the extent of high-grade mineralization. In 2023, 1,892 m of drilling was completed in 11 holes following up on the channel sample results. The drilling was successful in defining high-grade mineralization over an approximate strike extent of 50 m and depth of 150 m. This has been currently interpreted as a narrow, steeply plunging ore shoot, which remains open down-plunge. Additional high-grade mineralization was intersected in vein arrays within 50 m of the Pine Zone, further supporting the presence of a significant high-grade gold system.

New highlights include (Table 2):

Pine Zone

• 29.77 g/t Au over 9.31 m (23IGX057), including:
  • 59.15 g/t Au over 4.39 m, including:
    • 378.00 g/t Au over 0.37 m
• 3441.64 g/t Au over 0.67 m (23IGX043), including:
  • 6220.00 g/t Au over 0.37 m
• 79.44 g/t Au over 4.06 m (23IGX053), including:
  • 932.00 g/t Au over 0.33 m
• 7.22 g/t Au over 7.45 m (23IGX055), including:
  • 11.87 g/t Au over 3.43 m
• 3.12 g/t Au over 9.64 m (23IGX059), including:
  • 20.10 g/t Au over 0.36 m
    

Adjacent Vein Arrays

• 6.44 g/t Au over 7.26 m (23IGX050), including:
  • 63.1 g/t Au over 0.52 m
• 17.67 g/t Au over 1.44 m (23IGX053), including:
  • 23.60 g/t Au over 1.05 m

Follow-up drilling is planned in 2024 to further evaluate the geometry and extent of the high-grade mineralization, and to test the potential of the Pine Zone along strike.

Breccia Zone

The Breccia Zone is located along the intensely silicified NNW-trending regional scale Maskinonge Lake Fault, which is immediately adjacent to, and cross-cuts the Pine Zone (Figure 3). Alamos conducted prospecting in 2021, and completed follow up channel sampling in 2022, which was successful in discovering and defining a previously unrecognized 50 m long portion of the structure with continuous high-grade mineralization.

Systematic drilling of the structure below and along trend of the high-grade channel samples intersected narrow, high-grade mineralization; however, this was not representative of the continuity of high-grade gold mineralization from the surface channel samples. Additional high-grade mineralization was intersected in veins in a sulphide unit less than 10 m east of the Breccia Zone. New highlights from the Breccia Zone include (Table 2):

Breccia Zone

• 3.16 g/t Au over 7.38 m (23IGX063)
• 4.39 g/t Au over 3.05 m (23IGX035), including:
  • 33.1 g/t Au over 0.33 m
• 7.42 g/t Au over 1.92 m (23IGX040), including:
  • 13.15 g/t Au over 0.90 m
• 17.90 g/t Au over 0.33 m (23IGX046)
• 5.82 g/t Au over 2.84 m (23IGX048), including:
  • 12.55 g/t over 0.62 m
• 17.70 g/t Au over 0.40 m (23IGX052)
  

Adjacent Vein Array

• 40.29 g/t Au over 2.3 m (23IGX062), including:
  • 146.5 g/t Au over 0.45 m
  • 55.3 g/t Au over 0.40 m
    

Additional interpretation is underway to determine the relationship between the high-grade surface samples and drill results, with a focus on refining the controls on gold mineralization within the structure.

88-60 Zone

The 88-60 Zone is located approximately 7 km from the Island Gold Mine. The zone is located in proximity to the historic Cline and Edwards mines and had been drilled during historical exploration campaigns. Notable historical drill intercepts from these campaigns include³:

• 21.58 g/t Au over 8.17 m (CL-90-86), including:
  • 127.52 g/t Au over 0.73 m
  • 157.00 g/t Au over 0.31 m
  • 49.77 g/t Au over 0.58 m
• 12.68 g/t Au over 7.47 m (CL-90-85), including:
  • 32.38 g/t Au over 1.14 m
  • 61.03 g/t over 0.73 m
• 12.23 g/t Au over 5.95 m (CL-08-36), including:
  • 26.49 g/t Au over 1.98 m
  • 18.81 g/t Au over 0.61 m
• 5.12 g/t Au over 8.77 m (WCL-98-3), including:
  • 17.01 g/t Au over 1.98 m

³ Drill composite intervals are generated from assays that are historic in nature and that have been verified as best as possible through review of the historically reported data. Drill hole composite intervals reported as uncut, and composites lengths are reported as core length. Composites are calculated with a 0.5 g/t cut-off, maximum internal waste of 4 m, and no minimum thickness. Higher-grade intervals within the primary drillhole composite are reported as "Including" for any individual or consecutive samples with assay grades greater than 10 g/t Au.

Following extensive data compilation, re-logging and sampling of historic drill core, as well as geological modelling, the controls on gold mineralization were refined, and a potential high-grade plunge linking together the aforementioned historic results was identified at the intersection of a NW-trending structure with the east-west trending 88-60 shear zone. The 2023 drill program at the 88-60 Zone was designed to test this interpretation, specifically along the intersection of the two structures. Three holes, totalling 849 m were drilled along the interpreted high-grade plunge, with all holes intersecting sulphides and strong alteration in the 88-60 zone, as well as visible gold in drill holes 23IGX065 and 23IGX066. Additional high-grade mineralization was intersected in vein arrays within 60 m of the 88-60 Zone, further supporting the presence of a significant high-grade gold system.

New highlights from the 88-60 Zone (Table 2) include:

• 6.00 g/t Au over 11.18 m (23IGX066), including:
  • 19.79 g/t Au over 1.12 m
  • 20.90 g/t Au over 0.78 m
  • 24.60 g/t Au over 0.58 m

Adjacent Vein Arrays

• 14.62 g/t Au over 1.5 m (23IGX066), including:
  • 21.80 g/t over 0.94 m
• 6.19 g/t Au over 3.31 m (23IGX065), including:
  • 55.50 g/t over 0.34 m

Follow-up drilling is planned in 2024 to further define the extent and gold potential of the identified high-grade mineralization, as well as test other mineralized trends within the 88-60 zone and surrounding past-producing Cline and Edwards mines.

Systematic regional exploration has been successful in identifying and drilling priority high-grade gold targets throughout the regional Island Gold property. This approach will continue to be applied in 2024 to identified targets, and to the newly expanded 55,300 hectare land package.

Qualified Persons

Scott R.G. Parsons, P.Geo., FAusIMM, Alamos Gold's Vice President, Exploration, has reviewed and approved the scientific and technical information contained in this news release. Scott R.G. 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, P.Geo., Chief Geologist at the Island Gold Mine. Tyler 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 Gold maintains an internal Quality Assurance / Quality Control (QA/QC) program at the Island Gold Mine to ensure sampling and analysis of all exploration work is 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 laboratory, and regional samples are delivered to ALS laboratory, both located in Thunder Bay, Ontario.

Gold is analyzed by a 50 grams fire assay with an Atomic Absorption (AA) finish. Mine samples greater than 10.0 g/t Au, and regional samples greater than 5.0 g/t Au are re-analyzed using gravimetric finish methods. AGAT and ALS are certified laboratories and have internal quality control ("QC") 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 August 29, 2022 Technical Report filed on SEDAR+ (www.sedarplus.ca).

About Alamos

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+ 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 TSX and NYSE under the symbol "AGI".

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All amounts are in United States dollars, unless otherwise stated

The TSX and NYSE have not reviewed and do not accept responsibility for the adequacy or accuracy of this release.

Cautionary Note

This news release includes certain statements that constitute forward-looking information within the meaning of applicable Canadian and U.S. securities laws ("forward-looking statements"). All statements in this news release other than statements of historical fact, which address events, results, outcomes, or developments that Alamos expects to occur are forward-looking statements. Forward-looking statements are generally, but not always, identified by the use of forward-looking terminology such as "expect", "plan", "estimate", "target", "budget", "prospective" "potential", "opportunity" or variations of such words and phrases and similar expressions or statements that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved or the negative connotation of such terms.

Such statements in this news release include, without limitation, statements with respect to planned exploration programs, focuses, strategies, drilling targets and work, potential for further exploration of certain areas, potential drilling results and related expectations, costs and expenditures, including with respect to the cost of development and production, project economics, gold price assumptions, potential mineralization, projected ore grades, opportunities to add near mine and further high-grade Mineral Reserves and Resources, expectations regarding the mine plan, mine life, sustaining capital and value of operations and other statements and information that is based on forecasts and projections of future operational, geological or financial results, estimates of amounts not yet determinable and assumptions of management.

Exploration results that include geophysics, sampling, and drill results on wide spacings may not be indicative of the occurrence of a mineral deposit. Such results do not provide assurance that further work will establish sufficient grade, continuity, metallurgical characteristics and economic potential to be classed as a category of Mineral Resource. A Mineral Resource that is classified as "inferred" or "indicated" has a great amount of uncertainty as to its existence and economic and legal feasibility. It cannot be assumed that any or part of an "Indicated Mineral Resource" or "Inferred Mineral Resource" will ever be upgraded to a higher category of Mineral Resource. Investors are cautioned not to assume that all or any part of mineral deposits in these categories will ever be converted into Proven and Probable Mineral Reserves.

Alamos cautions that forward-looking statements are necessarily based upon several factors and assumptions that, while considered reasonable by management at the time of making such statements, are inherently subject to significant business, economic, technical, legal, political and competitive uncertainties and contingencies. Known and unknown factors could cause actual results to differ materially from those projected in the forward-looking statements, and undue reliance should not be placed on such statements and information.

These factors and assumptions include, but are not limited to: the actual results of current exploration activities, conclusions of economic and geological evaluations, changes in project parameters as plans continue to be refined, operations may be exposed to illness, disease, epidemic or pandemic; any ongoing or future impact of COVID-19 on the broader market; state and federal orders or mandates (including with respect to mining operations generally or auxiliary businesses or services required for the Company's operations) in Canada, Mexico and other jurisdictions in which the Company does or may conduct business; the duration of regulatory responses to any illness, disease, epidemic or pandemic; changes in national and local government legislation, controls or regulations; failure to comply with environmental and health and safety laws and regulations; labour and contractor availability (and being able to secure the same on favourable terms); ability to sell or deliver gold doré bars; disruptions in the maintenance or provision of required infrastructure and information technology systems; fluctuations in the price of gold or certain other commodities such as, diesel fuel, natural gas, and electricity; operating or technical difficulties in connection with mining or development activities, including geotechnical challenges and changes to production estimates (which assume accuracy of projected ore grade, mining rates, recovery timing and recovery rate estimates and may be impacted by unscheduled maintenance); changes in foreign exchange rates (particularly the Canadian dollar, U.S. dollar, and Mexican peso); the impact of inflation; employee and community relations; litigation and administrative proceedings; disruptions affecting operations; availability of and increased costs associated with mining inputs and labour; delays in the development or updating of mine plans; inherent risks and hazards associated with mining and mineral processing including environmental hazards, industrial accidents, unusual or unexpected formations, pressures and cave-ins; the risk that the Company's mines may not perform as planned; uncertainty with the Company's ability to secure additional capital to execute its business plans; the speculative nature of mineral exploration and development, risks in obtaining and maintaining necessary licenses, permits and authorizations, contests over title to properties; expropriation or nationalization of property; political or economic developments in Canada or Mexico and other jurisdictions in which the Company does or may carry on business in the future; increased costs and risks related to the potential impact of climate change; the costs and timing of construction and development of new deposits; risk of loss due to sabotage, protests and other civil disturbances; the impact of global liquidity and credit availability and the values of assets and liabilities based on projected future cash flows; and business opportunities that may be pursued by the Company.

For a more detailed discussion of such risks and other factors that may affect the Company's ability to achieve the expectations set forth in the forward-looking statements contained in this news release, see the Company's latest 40-F/Annual Information Form and Management's Discussion and Analysis, each under the heading "Risk Factors", available on the SEDAR+ website at www.sedarplus.ca or on EDGAR at www.sec.gov. The foregoing should be reviewed in conjunction with the information and risk factors and assumptions found in this news release.

The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether written or oral, or whether as a result of new information, future events or otherwise, except as required by applicable law.

Note to U.S. Investors - Mineral Reserve and Resource Estimates

Unless otherwise indicated, all Mineral Resource and Mineral Reserve estimates included in this news release have been prepared in accordance with National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101") and the Canadian Institute of Mining, Metallurgy and Petroleum (the "CIM") - CIM Definition Standards on Mineral Resources and Mineral Reserves, adopted by the CIM Council, as amended (the "CIM Standards"). NI 43-101 is a rule developed by the Canadian Securities Administrators, which established standards for all public disclosure an issuer makes of scientific and technical information concerning mineral projects. Mining disclosure in the United States was previously required to comply with SEC Industry Guide 7 ("SEC Industry Guide 7") under the United States Securities Exchange Act of 1934, as amended. The U.S. Securities and Exchange Commission (the "SEC") has adopted final rules, to replace SEC Industry Guide 7 with new mining disclosure rules under sub-part 1300 of Regulation S-K of the U.S. Securities Act ("Regulation S-K 1300") which became mandatory for U.S. reporting companies beginning with the first fiscal year commencing on or after January 1, 2021. Under Regulation S-K 1300, the SEC now recognizes estimates of "Measured Mineral Resources", "Indicated Mineral Resources" and "Inferred Mineral Resources". In addition, the SEC has amended its definitions of "Proven Mineral Reserves" and "Probable Mineral Reserves" to be substantially similar to international standards.

Investors are cautioned that while the above terms are "substantially similar" to CIM Definitions, there are differences in the definitions under Regulation S-K 1300 and the CIM Standards. Accordingly, there is no assurance any mineral reserves or mineral resources that the Company may report as "proven mineral reserves", "probable mineral reserves", "measured mineral resources", "indicated mineral resources" and "inferred mineral resources" under NI 43-101 would be the same had the Company prepared the mineral reserve or mineral resource estimates under the standards adopted under Regulation S-K 1300. U.S. investors are also cautioned that while the SEC recognizes "measured mineral resources", "indicated mineral resources" and "inferred mineral resources" under Regulation S-K 1300, investors should not assume that any part or all of the mineralization in these categories will ever be converted into a higher category of mineral resources or into mineral reserves. Mineralization described using these terms has a greater degree of uncertainty as to its existence and feasibility than mineralization that has been characterized as reserves. Accordingly, investors are cautioned not to assume that any measured mineral resources, indicated mineral resources, or inferred mineral resources that the Company reports are or will be economically or legally mineable.

Table 1: Island Gold - Previously Unreleased Select Composite Intervals from Underground Exploration Drilling

Composite intervals greater than 3 g/t Au weighted average, capping values:

C-zone @ 225 g/t Au; E1E Zone @ 185 g/t Au; B Zone @ 90 g/t Au; D1 and G1 Zones @ 45 g/t Au; G Zone @ 70 g/t Au; E1D @ 80g/t Au; NS1 Zone @ 60 g/t Au; DN, E1D1, NTH1, NTH2, NTH3, NTH4 @ 35 g/t Au.

Table 2: Island Gold Regional Exploration - Previously Unreleased Select Composite Intervals from 2023 Surface Exploration Drilling

Composites grades are reported as uncut, and length is reported as core length. True width is estimated to be 40 to 85% of core length. Composite intervals greater than 1 g/t Au weighted average.

Composites are calculated with a 0.5 g/t cut off, maximum internal waste of 4 m, and no minimum width. Higher-grade intervals within the primary drillhole composite are reported as "Including" for any individual or consecutive samples with assay grades greater than 10 g/t Au.

A total of 42 holes were completed in 2023 as part of the regional drilling program (in addition to 2 abandoned holes). Of the 42 holes drilled, 4 holes contained composite intervals less than 1 g/t Au, and 2 holes had no significant values. Assays are pending for 5 holes.

Table 3: Underground exploration drill holes; azimuth, dip, drilled length, and collar location at surface (UTM NAD83).

Note: UTM mine surface elevation 393 m

Table 4: Surface exploration drill holes; azimuth, dip, drilled length, and collar location (UTM NAD83).

Figure 1: Island Gold Mine - C/E1E/E1EN/E1D Longitudinal, New C and E1E-Zone Underground Exploration Drilling Results

Figure 2: Island Gold East - Highlights from NTH4 Footwall Zone

Figure 3: Island Gold Regional - Pine Target

Photos accompanying this announcement are available at:

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