Mr. Darwin Green reports

MACKAY GOLD & SILVER ADDS SECOND DRILL RIG TO TEST THE HISTORIC SUTRO TUNNEL INTERSECTION OF THE OCCIDENTAL-BRUNSWICK LODE AT DEPTH, COMSTOCK DISTRICT, NEVADA

A diamond core drill rig has been mobilized to Mackay Gold & Silver Corp.'s 100-per-cent-owned Comstock district project in Nevada and has commenced drilling. The addition of the core rig marks the start of the approximately 5,000-metre (m) core drilling component of the company's inaugural 20,000-metre phase 1 drill program and will operate alongside the reverse circulation (RC) rig that has been drilling since mid-June.

Drill plan and update:

• Core drill rig now turning, joining the RC rig as part of a two-rig 20,000-metre phase 1 drill program;
• Initial priority target for the core rig is the historical Sutro tunnel intersection, where late 1870s tunnelling reportedly crossed a 100-foot-wide (30-metre) interval of the Occidental-Brunswick vein 1,500 feet (450 metres) below surface, an intersection that has never been drill tested;
• Core holes are planned at approximately 100-metre spacing, targeting above, below and along strike of the historical tunnel intersection;
• A total of 25 RC holes for approximately 4,000 metres has been completed to date at Occidental South, targeting shallow oxide-gold mineralization associated with a strong gold-in-soil anomaly;
• Assays are pending for all drill holes, with first RC results expected in the coming weeks;
• The company is fully financed following a go-public financing in April, 2026, that raised approximately $60-million (U.S.).

"Pace has quickened with the addition of the second rig, enabling us to drill both our priority target areas at the same time," commented Darwin Green, chief executive officer of Mackay Gold & Silver. "The RC rig continues to systematically test a shallow oxide-gold target along the southern end of the Occidental-Brunswick lode, while the core rig goes after what we believe is one of the largest and most compelling untested targets in the district -- the Occidental-Brunswick lode at depth. During its construction 150 years ago, the nearly four-mile long Sutro tunnel crosscut a 100-foot-wide interval of the Occidental-Brunswick vein that has never been followed up with a single drill hole. This represents the starting point of our exploration of the deeper portions of the multikilometre-long Occidental-Brunswick lode, which we believe has excellent potential to host high-grade mineralization like the famous bonanzas of the Comstock lode."

The Occidental-Brunswick lode and the Sutro tunnel target

The Occidental-Brunswick lode is a three-mile-long (five-kilometre (km)) mineralized structure located east of, and parallel to, the Comstock lode. It shares the same strike, dip, and overall geological setting and character as its better-known neighbor. The company interprets postmineral faulting to have downdropped the Occidental-Brunswick relative to the Comstock. On that interpretation, the vertical range of the vein structure that hosted the richest Comstock lode deposits is projected to lie at depth beneath the historical workings on the Occidental-Brunswick, beyond the reach of 19 century miners and untested by modern drilling.

Physical evidence for the presence of the vein structure at depth comes from the Sutro tunnel. Completed in the late 1870s as a four-mile (6.5 km) gravity drainage tunnel connected to the 1,640-foot (500 m) level of the main Comstock mines, the tunnel was driven perpendicular to the strike of the district's lodes. In doing so, it reportedly crossed a 100-foot-wide (30 m) interval of the Occidental-Brunswick vein more than 1,500 feet (450 meters) below surface. Historical reports indicate the interval to be mineralized but below the cut-off grade of the day (estimated at eight to 10 grams per tonne (g/t) gold (Au)). The tunnel is no longer accessible and this intersection has never been drill tested.

Core drilling is designed to systematically test the depth projection of the Occidental-Brunswick vein at approximately 100-metre spacing, targeting above, below and on either side of the historical Sutro tunnel. Diamond core drilling will provide the structural and geological detail needed to understand the geometry, controls and grade distribution of the vein at depth.

District-scale potential of the Comstock

The Comstock district is recognized as one of America's highest-grade epithermal gold-silver systems. Between 1859 and 1926, the district produced approximately 8.2 million ounces of gold and 192 million ounces of silver, with the historical bonanza lodes averaging approximately 35 g/t gold and 726 g/t silver. Despite this production history, the district has seen remarkably little modern, systematic exploration. Historical mining was concentrated on high-grade shoots accessible with the technology of the era and the district's fragmented ownership prevented consolidated, district-wide exploration for more than a century.

Mackay has consolidated a dominant land position across the district, allowing targets to be tested systematically for the first time. The 2026 program pairs RC drill rig testing of shallow, oxide mineralization at 100 to 250 m depths across 80 to 100 drill holes within a 1,000 m by 400 m area at the Occidental South zone, with the core rig now testing the deeper, high-grade potential of the Occidental-Brunswick structure.

About Mackay Gold & Silver Corp.

Mackay Gold & Silver is a Nevada-focused gold and silver exploration company with 100-per-cent control of a large, consolidated land package in one of America's richest, productive and oldest mining districts. With an estimated 8.2 million ounces of historical gold production and 192 million ounces of silver produced between 1859 and 1926 from so called bonanza lodes that averaged 35 g/t gold and 726 g/t silver, the Comstock district is recognized as one of America's highest-grade epithermal systems and an attractive setting for modern discovery. Led by an experienced team with a strong record of discovery, development and value creation, Mackay is well financed and committed to delivering shareholder value through disciplined exploration and responsible resource development.

Qualified person

The scientific and technical information contained in this news release has been reviewed and approved by Mr. Green a qualified person under National Instrument 43-101. Mr. Green is not independent of the company.

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