Alamos Gold Intersects Higher-Grade Mineralization within a New Zone Near Existing Infrastructure at Young-Davidson

Alamos Gold Inc. has reported new results from its underground exploration program at the Young-Davidson mine. Underground exploration drilling from the mid-mine intersected a new style of higher-grade gold mineralization in zones within the hanging wall of the Young-Davidson deposit.

Figure 1: Young-Davidson Mine Composite Longitudinal – 9620-Level Exploration Area

These zones are located between 10 and up to 200 metres (“m”) south of existing infrastructure and Mineral Reserves and Resources, highlighting the upside potential with grades intersected well above the current Mineral Reserve grade of 2.31 grams per tonne of gold (“g/t Au”).

  • Young-Davidson Hanging Wall Zones: high grade gold mineralization intersected within the hanging wall, in proximity to existing infrastructure and south of existing Mineral Reserves and Resources. This represents a new style of mineralization at Young-Davidson, hosted in hanging wall stratigraphy including a folded sequence of Timiskaming assemblage conglomerates and sediments. Gold mineralization is associated with 3-20% pyrite and occurs both as wide, low- to moderate-grade mineralization, and also within narrower, high-grade structures (Figures 1 and 2). New highlights include1:
    • 9620-Level Drilling1
      • 7.41 g/t Au over 22.00 m, including 15.84 g/t Au over 6.00 m (YMEX24-9620-143);
      • 19.94 g/t Au over 4.55 m (YMEX24-9620-147);
      • 21.86 g/t Au over 4.00 m (YMEX24-9620-147);
      • 5.24 g/t Au over 9.00 m (YMEX24-9620-147);
      • 9.07 g/t Au over 5.00 m (YMEX24-9620-137);
      • 4.70 g/t Au over 10.00 m (YMEX24-9620-143);
      • 17.55 g/t Au over 2.00 m (YMEX24-9620-142); and
      • 4.13 g/t Au over 8.31 m (YMEX24-9620-141).
    • 9500-Level Drilling1,2
      • 10.73 g/t Au over 15.55 m (YM23-9500-107A).

1 All reported composite intervals are core length and gold grades are reported as uncut. Based on initial review of core angles, true width is interpreted to be less than 50% of core length for some composites. Additional drilling and interpretation is ongoing to further define the geometry and extent of the mineralized zones.

2 YM23-9500-107A was drilled as a BQ-diameter definition drillhole, which was extended into the hanging wall. This hole was assayed using whole core at the Young Davidson on-site assay lab (see QA/QC section of Press Release).

Figure 2: Young-Davidson Mine Cross Section – 9620 & 9500-Level Exploration Drill Holes & Significant Composites

“Young-Davidson is a consistent, long-life operation with a long-track record of Mineral Reserve replacement having maintained at least a 13-year Mineral Reserve life since 2011. With the deposit open at depth and to the west, we expect this track record to continue well into the future as we extend gold mineralization within the Young-Davidson syenite. The new zones being discovered in the hanging wall highlight the significant exploration potential outside of the syenite. This is a new style of higher-grade mineralization, near our existing underground infrastructure, which has the potential to provide meaningful production upside,” said John A. McCluskey, President and Chief Executive Officer.

New highlight intercepts can be found in Tables 1 and 2, and in Figures 1 and 2.

2024 Exploration Drilling Program – Young Davidson

A total of $12 million has been budgeted for exploration at Young-Davidson in 2024, up from $8 million spent in 2023. This includes 21,600 m of underground exploration drilling, and 1,070 m of underground exploration development to extend drill platforms on multiple levels.

The majority of the ongoing underground exploration drilling program will focus on extending mineralization within the Young-Davidson syenite, which hosts the majority of Mineral Reserves and Resources. As part of the 2024 program, drilling was also planned to test gold mineralization in the hanging wall of the deposit where higher grades have been previously intersected.

As of May 1, 2024, two exploration drills completed 9,610 m in 26 holes from the 9220 West exploration drift, 9025 East footwall drift, 9305 East transfer, and the 9620 Hanging wall drift. Drilling from 9025, 9305, and 9220 west is targeting syenite-hosted mineralization. The 9620-level drilling is focused on testing for gold mineralization in the hanging wall sediments and mafic-ultramafic lithologies. Drilling from the 9025-level has also been successful at expanding gold mineralization within the syenite outside of current Mineral Reserves and Resources in the lower mine, in proximity to existing underground infrastructure.

Hanging Wall Gold Mineralization

An objective of the 2024 underground exploration drilling program is to test for gold mineralization in the hanging wall from a drill bay established on the 9620-level. This program is following up on gold mineralization that was intersected in surface drill holes completed between 2008 to 2010. These holes were collared south of Young-Davidson in the hanging wall, and drilled to the north, through the hanging wall. The surface holes were drilled to target the syenite-hosted mineralization, and as a result limited sampling was completed in the hanging wall lithologies at that time.

In addition, an underground definition drill hole completed from the 9500-level in the fourth quarter of 2023 intersected 10.73 g/t Au over 15.55 m (YM23-9500-107A) in a conglomerate, 93 m from the syenite-hosted Mineral Reserves and Resources. This definition hole had been extended into the hanging wall to test the potential for gold mineralization.

Following up on this intersection from the 9500-level definition drill hole (YM23-9500-107A), as well as underground mapping on the 9620-level, and the previous 2008-2010 surface drillhole intersections, underground exploration drilling commenced in the first quarter of 2024 from the 9620-level drill bay.

To date, 13 holes totalling 4,591 m have been completed from the 9620-level. New highlights include:

  • 9620-Level
    • 7.41 g/t Au over 22.00 m, including 15.84 g/t Au over 6.00 m (YMEX24-9620-143);
    • 19.94 g/t Au over 4.55 m (YMEX24-9620-147);
    • 1.02 g/t Au over 101.00 m (YMEX24-9620-136);
    • 21.86 g/t Au over 4.00 m (YMEX24-9620-147);
    • 5.24 g/t Au over 9.00 m (YMEX24-9620-147);
    • 9.07 g/t Au over 5.00 m (YMEX24-9620-137);
    • 4.70 g/t Au over 10.00 m (YMEX24-9620-143);
    • 17.55 g/t Au over 2.00 m (YMEX24-9620-142);
    • 4.13 g/t Au over 8.31 m (YMEX24-9620-141); and
    • 1.75 g/t Au over 18.00 m (YMEX24-9620-144).
  • 9500-Level
    • 10.73 g/t Au over 15.55 m (YM23-9500-107A).

Drilling is now underway from a drilling pad established to the east of the initial drilling on the 9620-level to continue to test for gold mineralization in the hanging wall, with the objective of better defining the extent, geometry, and continuity of the high-grade mineralization. In addition, a core relogging and sampling program is expected to commence in the second quarter of 2024, with a focus on evaluating the historic surface drilling in the hanging wall that had undergone limited sampling.

Table 1: Young-Davidson – Previously Unreleased Select Composite Intervals from Underground Exploration Drilling on the 9620-Level.

Weighted average composite intervals greater than 30 g*m

All reported composite intervals are core length and gold grades are reported as uncut. Based on initial review of core angles, true width is interpreted to be less than 50% of core length for some composites. Additional drilling and interpretation is ongoing to further define the geometry and extent of the mineralized zones.

Gold composites are generated using a 1.2 g/t Au cut-off and include no more than 2.0 m of consecutive internal waste.

Note that the gold composite reported for drill hole YMEX24-9620-136 is generated using a 0.5 g/t Au cut-off and includes no more than 8.0 m of consecutive internal waste given the wide, lower-grade extent of gold mineralization.

Hole ID
Including
From (m)
To (m)
Core Length
(m)
Au Uncut
(g/t)
Vertical
Depth from
Surface (m)
YMEX24-9620-136 60.00 161.00 101.00 1.02 536
YMEX24-9620-137 178.00 183.00 5.00 9.07 605
YMEX24-9620-141 57.69 66.00 8.31 4.13 540
YMEX24-9620-142 247.00 249.00 2.00 17.55 660
YMEX24-9620-143 25.00 35.00 10.00 4.70 540
41.00 63.00 22.00 7.41 555
Including 41.00 47.00 6.00 15.84 555
YMEX24-9620-144 51.00 69.00 18.00 1.75 569
YMEX24-9620-147 17.00 26.00 9.00 5.24 533
35.00 39.00 4.00 21.86 543
184.50 189.05 4.55 19.94 645


Table 2: Young-Davidson – Previously Unreleased Select Composite Intervals from Underground Definition Drilling on the 9500-Level.

All reported composite intervals are core length and gold grades are reported as uncut. Based on initial review of core angles, true width is interpreted to be less than 50% of core length. Additional drilling and interpretation is ongoing to further define the geometry and extent of the mineralized zones.

The gold composite was generated using a 1.2 g/t Au cut-off and includes no more than 1.5 m of consecutive internal waste.

Definition drilling was completed with BQ-diameter core. This hole was assayed using whole core at the Young Davidson on-site assay lab.

Hole ID
From
(m)

To (m)
Core Au Uncut
(g/t)
Vertical Depth
 Length from Surface
(m) (m)
YM23-9500-107A 307.92 323.47 15.55 10.73 673


Table 3: Underground Drill Holes, 9620 and 9500-Level; Azimuth, Dip, Drilled Length, and Collar Location (UTM NAD83).

Hole ID Azimuth
(°)
Dip
(°)
Drilled UTM Easting (m) UTM Northing
(m)
UTM Elevation
(m)
Length 
(m)
YMEX24-9620-136 164.5 -9.5 699.0 523055 5310195 -368
YMEX24-9620-137 164.5 -29.5 234.0 523055 5310194 -369
YMEX24-9620-138 164.5 -42.0 273.0 523055 5310195 -369
YMEX24-9620-139 164.5 -54.5 315.0 523055 5310195 -369
YMEX24-9620-140 164.5 4.5 204.0 523055 5310194 -368
YMEX24-9620-141 178.5 -21.5 252.0 523054 5310195 -369
YMEX24-9620-142 178.5 -35.0 330.0 523054 5310195 -369
YMEX24-9620-143 178.5 -47.0 408.0 523054 5310195 -370
YMEX24-9620-144 178.5 -62.5 321.0 523054 5310195 -367
YMEX24-9620-145 192.5 -5.0 291.7 523054 5310195 -368
YMEX24-9620-146 192.5 -25.0 315.0 523053 5310195 -369
YMEX24-9620-147 192.5 -43.5 561.0 523053 5310195 -369
YMEX24-9620-154 178.5 14.0 387.0 523054 5310195 -368
YM23-9500-107A 182.5 -7.0 357.0 523030 5310408 -496

Note: UTM mine surface elevation 350 m

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