Pinnacle Minerals Limited is advancing exploration and redevelopment plans at its Thunder Mountain Gold-Silver Project in Idaho, USA, launching a fast-tracked mine restart study targeting the historic Lightning Peak Open Pit.
The restart study includes technical fieldwork, sampling, and 3D modelling of the historic Lightning Peak pit, which lies just eight kilometers from Perpetua Resources Inc.’s A$4 billion Stibnite Gold-Antimony Project. Pinnacle is conducting field mapping, sampling, and geophysical analysis to assess the project’s restart potential and define new drill targets.
Key components of the exploration program include:
- Ongoing mapping and sampling confirming the continuation of mineralization across Thunder Mountain tenements.
- Review and validation of historic USGS and Idaho Geological Survey data to support modern 3D pit modelling.
- Processing of airborne magnetic and satellite data to identify structural controls and new high-priority drill targets.
- Engagement with U.S. consultants and local authorities to establish permitting pathways for drilling and mine redevelopment.
- Assay results from rock chip and channel sampling expected in the coming weeks to feed into the restart study.
Located in Valley County, Idaho, the Thunder Mountain Project covers approximately 368 hectares within a historically productive gold and silver district. The area shares similar geological characteristics to Perpetua’s Stibnite Project, including host rocks, alteration styles, and mineralization.
Historic Mining Context
Gold was first discovered at Thunder Mountain in 1896, sparking a significant gold rush and leading to the establishment of the town of Roosevelt in 1902. The district recorded substantial production in the early 1900s, with modern mining undertaken by Coeur d’Alene Mines between 1986 and 1992, producing over 100,000 ounces of gold from the Sunnyside and Lightning Peak Mines.
The Lightning Peak Open Pit, developed as part of Coeur d’Alene’s Sunnyside operation, produced approximately 25,000 ounces of gold and 30,000 ounces of silver in 1990. The operation historically targeted ore bodies hosted in silicified breccias and volcanic tuffs, with grades ranging up to 1.0 ounce per ton of gold.
Pinnacle’s U.S. Expansion
The current exploration initiative at Thunder Mountain forms part of Pinnacle’s strategic expansion across the United States, where the Company is building a critical minerals and precious metals portfolio. The project lies within the Eocene-aged Challis Volcanic Field, a highly prospective geological setting hosting low-sulphidation epithermal gold-silver systems.
Executive Commentary
Pinnacle’s Executive Chairman, William Witham, said:
“Our work at Thunder Mountain represents a genuine opportunity to bring historic U.S gold and silver mines back to life using modern exploration and technology. So far, this is an excellent result from our restart study at the Project, and it marks an important milestone as Pinnacle transitions into an active explorer across its growing U.S. critical minerals portfolio.
“The verification of historical workings and confirmation of mineralization within the project area reinforce the quality of the asset and highlight its strong potential. We look forward to advancing exploration to define high-priority drill targets and deliver value for shareholders.”
Next Steps
Geophysical and remote sensing work is underway, including the processing of airborne magnetic data and satellite imagery to define new target areas and guide field mapping. These results will support drill targeting and permitting as Pinnacle moves toward a potential mine restart.