Thunder Mountain Gold launches 2026 drill program at South Mountain

Boise, Idaho--(Newsfile Corp. - June 22, 2026) - Thunder Mountain Gold, Inc. (OTCQB: THMG) (TSXV: THM) ("Thunder Mountain Gold" or the "Company") is pleased to announce the launch of its 2026 exploration drilling campaign at the South Mountain Project in southern Idaho (the " South Mountain " or the " Project "). The Company's initial 10,000-foot program is designed to expand the established carbonate replacement deposit (CRD) silver, zinc, copper, lead and gold massive sulfide resource, while also advancing the first drill tests of compelling district-scale copper-gold targets. This new campaign marks an important step in unlocking the broader value potential of the South Mountain district for shareholders and resource investors worldwide.

Drilling Focus for 2026 Resource Expansion and Step-Out Potential - The initial 10,000-foot program is now underway and is designed to accelerate expansion of the CRD massive sulfide resource along strike, representing approximately twice the surface core drilling completed to date at South Mountain. The program will also test compelling magnetotelluric (MT) and induced polarization (IP) geophysical anomalies that are spatially associated with the known resource and supported by surface geological mapping, highlighting a strong opportunity to expand the mineralized footprint and advance the knowledge across the Project. Testing New MT and Geological Targets - In 2025, the Company began an ambitious district-wide exploration program aimed at identifying the potential source or sources of the polymetallic massive sulfide mineralization and additional mineralized zones within the Laxey Marble.

Integrated modeling of MT and surface geological data outlined several highly prospective anomalies (see Figure 1) including anomalies below the Gold Breccia target, further supported by historic IP data and more recent pulse electromagnetic (PEM) and ground magnetic surveys.