Hercules Idaho copper discovery: drilling scale-up and resource path for engineers
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Hercules Metals has extended the Southern Flats porphyry copper discovery at its Hercules project in Idaho, with hole HER-26-01 cutting 286.5 metres grading 0.43% copper from 862.6 metres downhole, including 65.5 metres at 0.61% copper. Two rigs are now drilling south from the Leviathan zone into a roughly 1 km gap towards Southern Flats, where Leviathan mineralisation already tracks over 1.35 km along strike, up to 750 metres wide and 500 metres vertically, all still open. Backed by C$4.5 million of insider funding and a 10.3% Barrick stake, management is planning 80,000–100,000 metres of drilling in 2027 on a 200-metre grid to support an inferred resource.
Technical Brief
- Latest Southern Flats hole HER-26-01 is a 200 m step-out west of the discovery hole.
- Reported mineralised intervals are drilled lengths only; true widths are currently unconstrained.
- Leviathan currently has two rigs drilling south into the ~1 km gap towards Southern Flats, with HER-26-04 assays pending.
- Two additional rigs are scheduled for October, taking Leviathan’s fleet to four, with at least two more sought for 2027.
- Total drilling to date is ~30,000 m, versus a contemplated 80,000–100,000 m campaign in 2027 on a 200 m grid.
- At Hook, ~3 km east of Leviathan, the maiden hole into a geophysical chargeability anomaly intersected phyllic alteration with disseminated and D-type pyrite veins from ~100 m depth.
- Road access to Hook requires U.S. Forest Service approval; permits are targeted by late 2026 or early 2027, enabling Q1 road/pad construction and Q2 drilling.
- Hercules controls ~404.7 km² over 73 km of the Olympus copper belt through ownership and option agreements, with Barrick holding a 10.3% equity stake.
- Incoming management, including six former Arizona Sonoran Copper executives, invested C$4.5 million, leaving ~C$3.2 million cash to fund work through mid-2027 before further raises.
Our Take
The arrival of six former Arizona Sonoran Copper leaders who previously took the Cactus project to a US$1.4 billion sale to Hudbay (as noted in the July 31 piece) signals that Hercules Metals is likely positioning Leviathan and the wider Olympus copper belt for a scale and de‑risking pathway attractive to major acquirers such as Barrick Mining, which already holds a 10.3% stake.
With Leviathan mineralisation already traced over 1.35 km strike and a 1 km gap to Southern Flats, the planned 200 m drill grid and four‑rig fleet by October suggest Hercules is racing to a belt‑scale inferred resource by mid‑2027, which in our database is an unusually aggressive timetable for an Idaho copper project of this footprint (404.7 sq. km across a 73 km belt).
The related September 15 coverage on the Hook target’s 1.8 km chargeability anomaly, starting from roughly 100 m depth and sitting 3 km east of Leviathan, implies that Hercules could be dealing with a multi‑centre porphyry system; if confirmed, this would give the company optionality between a single large hub‑and‑spoke development or multiple staged copper assets in western Idaho.
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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