Dr. Jean-Francois Montreuil reports

MACDONALD MINES COMPLETES DRILLING AT ALWYN CU-AU AND GLADE AU TRENDS OBSERVES VISIBLE GOLD AT GLADE

MacDonald Mines Exploration Ltd. has provided an update on the spring drill program undertaken at the Alwyn copper-gold trend and the Glade gold trend on its 100-per-cent-owned SPJ property in Sudbury, Ont.

Summary of drill program

• On June 28, 2023, the company completed 1,206 metres of oriented diamond drilling, including 954 metres of drilling at the Alwyn Cu-Au trend and 252 metres of drilling at the Glade Au trend.
• Intersection of a broad and near-surface potential zone of gold mineralization at Glade:
  • Visible gold in quartz-carbonate-chlorite veining identified periodically over 40 metres in hole AG-23-111. This zone is located 20 to 60 metres away from intercepts identified in 2021 drilling in hole AG-21-097 (see news release of May 13, 2023).
  • This area has been selected for rush assay analysis and drill core will be sent shortly.
  • Extension of possible PGM mineralization at depth.
  • Disseminations of pyrrhotite and chalcopyrite occur in Nipissing diabase and within quartz-carbonate veins between 128 and 149 metres and between 212 and 222 metres in hole AG-23-111.
  • Comparable sulphide assemblage was associated with PGM mineralization in hole AG-22-103, 45 metres northeast (see news release from Sept. 19, 2022).
• Hydrothermal iron enrichments observed in drilling 300 metres southeast of historic Alwyn mine:
  • Stringers to zones of semi-pervasive replacement of sedimentary textures by magnetite and/or Fe-rich chlorite, as well as veinlets of K-feldspar-chlorite-fluorite-chalcopyrite and specular hematite in holes AW-23-109 and AW-23-110 could be suggestive of the presence of iron-rich copper-gold mineralization affiliated with an iron-oxide-copper-gold (IOCG) deposit.

Dr. Jean-Francois Montreuil, PGeo, and chief geologist of MacDonald Mines, commented: "Observing seeping and intensifying iron oxide and silicate alteration in the Alwyn Cu-Au trend, as well as an association of chalcopyrite mineralization with iron-rich alteration types is a positive development of our drilling program in the area. These observations are supportive of the presence of a hydrothermal system capable of forming iron-rich mineralization types affiliated with iron-oxide-copper-gold (IOCG) deposits."

Dr. Montreuil added: "In the Glade Au trend, our initial observations from our 2023 drilling program indicate that the gold mineralized system discovered in 2021 extends at depth in the Nipissing intrusions and along the Espanola-Nipissing contact. With additional observations indicative of an association between Fe-rich chlorite and gold mineralization in the Glade Au trend, we also have additional evidence supporting an association with gold mineralization at the Scadding deposit."

Glade gold target

Two thousand twenty-three drilling at Glade continues to demonstrate near-surface zones of gold mineralization hosted in quartz-carbonate veins, as demonstrated by visible gold found in four locations over 40 metres in hole AG-23-111, at 8.9, 17.9, 28.0 and 51.0 metres. These observations occur approximately 55 metres laterally from the significant intercept measured in 2021 in hole AG-21-097, which consisted of 113 grams per tonne gold over 0.96-metre core length (see news release of May 13, 2021). Gold mineralization and Fe-rich alteration types observed in the Glade Au trend are comparable with the styles observed at the Scadding deposit, located approximately one kilometre to the north of Glade.

In the Glade Nipissing intrusion, the 2022 drilling program intersected 0.16 g/t Pd over 4.00 metres in hole AG-22-103 with anomalous Cu and Ni within a more mafic domain of the Glade Nipissing intrusion. This was a new observation for the Nipissing diabase in the Glade area, suggesting PGE-Ni-Cu potential for the intrusive unit. Observations of increased pyrrhotite and chalcopyrite between 128 and 149 metres, as well as between 212 and 222 metres in the new drilling from hole AG-23-111 could provide new insights into the variability of platinum group metals and size potential for this mineralization.

Copper-gold mineralization along the McLaren Lake fault zone

The MLFZ is emerging as a compelling exploration target for copper-gold and potentially cobalt-gold mineralization. Along the 2.5 km Alwyn Cu-Au trend defined in collaboration with ALS GoldSpot, near-surface copper-gold mineralization is associated with networks of quartz-carbonate veins. The 2023 gravity survey and data from the 2022 and 2023 drilling programs indicate that Cu-Au mineralization can also be associated with iron-rich alteration in the lateral and deeper extensions of the systems (see news releases of March 3, 2023, and June 13, 2023).

Regionally, the MLFZ is highly prospective for critical and precious metals mineralization. In addition to Alwyn, along the MLFZ on the SPJ project the primary targets include the Ashigami and the Crerar showings, located 4.5 kilometres and 9.5 km southeast of the Alwyn mine, respectively.

Qualified person

Dr. Jean-Francois Montreuil, PGeo, chief geologist of MacDonald Mines, is the qualified person as defined by National Instrument 43-101 Standards of Disclosure for Mineral Projects, responsible for preparing, supervising and approving this news release's scientific and technical content.

About MacDonald Mines Exploration Ltd.

MacDonald Mines is a Canadian exploration company focused on exploring for critical and precious metals in a metasomatic iron alkali-calcic (MIAC) mineral system on its 100-per-cent-owned, 19,720-hectare (197.2-square-kilometre) SPJ project. MIAC systems are known for hosting IOCG and affiliated deposits. The property is located 20 km southeast of the prolific Sudbury mining camp in Northern Ontario. The company's primary exploration focuses are the polymetallic and iron-poor to possibly iron-rich Ag-Au-Cu-Co showings and prospects along the McLaren Lake fault system that include the Alwyn Cu-Au-(Ag-Co) trend and the Ashigami Co-Cu-Au showings, and the iron-rich to iron-poor Glade Au trend recognized to host Au mineralization comparable with the Scadding deposit. In addition, a potential for nickel, cobalt, copper and platinum group elements in the Nipissing intrusions that are hosting the Candore, Jerome and Glade showings within the SPJ project.

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