Perpetua’s Stibnite project: Fiddle discovery implications for mine design and feed grade
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
New drilling at Perpetua Resources’ $1.3 billion Stibnite Gold project in Idaho has defined the Fiddle discovery, where hole SB633 cut 109.7 metres at 3.2 g/t gold and 1.1% antimony from 189 metres downhole, more than double the project’s life-of-mine average grade. Fiddle lies about 750 metres south of the permitted Yellow Pine pit on the north-trending Meadow Creek Fault Zone, with 21 follow-up holes logged showing abundant stibnite and sulphides. Additional drilling on the nearby Clark Tunnel Fault Zone returned near-surface intercepts including 25.4 metres at 4.5 g/t gold from 13 metres (SB606) and 25.0 metres at 2.3 g/t gold from 18 metres (SB605), indicating potential for higher-grade feed close to existing pit designs.
Technical Brief
- 2026 exploration campaign completed over 16,000 metres of core drilling across the Stibnite project area.
- Stibnite capex is estimated at US$1.3 billion, now advancing through early construction activities.
- Planned operation targets c.450,000 oz gold per year, underpinned by more than six million oz reserves.
- Proven and probable reserves also include 148 million lb antimony, positioning Stibnite as a major US source.
- Meadow Creek Fault Zone is identified as the district’s principal ore-controlling structure linking Yellow Pine and Hangar Flats.
- Three dedicated holes, including SB637, were drilled to test structural controls along the Meadow Creek Fault Zone.
- SB637 extended mineralisation northwards, intersecting 37.4 metres at 0.7 g/t Au and 0.1% Sb from 93.8 metres.
- Fiddle and Clark Tunnel Fault Zone were explicitly prioritised in the 2026 programme due to proximity to the permitted Yellow Pine pit.
Our Take
The new gold and antimony intercepts at Fiddle and the Clark Tunnel Fault Zone sit on top of a project that already has more than six million ounces of gold and 148 million pounds of antimony in reserves, which in our database places Stibnite among the larger undeveloped gold–antimony assets in North America by contained metal.
Earlier 2026 drilling between the Yellow Pine and West End pits highlighted gold‑tungsten potential, and the current results along the Meadow Creek and Clark Tunnel fault zones suggest the structural corridor around Yellow Pine could support a multi‑centre, multi‑commodity resource model rather than a single‑pit gold‑antimony story.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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