Alkane’s thousand g/t Costerfield hits: design and dilution notes for mine planners
Reviewed by Tom Sullivan

First reported on Australian Mining
30 Second Briefing
Alkane Resources has defined a new high‑grade mineralised zone within the Cuffley Lode at its Costerfield gold–antimony mine in Victoria, using 23 diamond drill holes into previously unmined ground between historical high‑grade Cuffley panels. Intercepts include 0.61m at 580.9g/t gold and other “thousand grams per tonne” hits, pointing to very narrow but ultra‑high‑grade vein structures typical of the district. For mine planners and geotechs, the results suggest potential for additional high‑margin stopes but with challenging ground control and dilution management in sub‑metre widths.
Technical Brief
- New mineralised zone sits within the existing Cuffley Lode footprint at Costerfield, not a satellite discovery.
- Target area lies between historically mined high‑grade Cuffley panels, implying remnant, previously unrecognised shoots.
- All 23 holes were diamond core, giving good structural and geotechnical information for narrow‑vein modelling.
- Discovery is within an operating gold–antimony mine, so access, services and ventilation are already established.
- Location in a mature underground camp suggests potential to tie new stopes into existing decline and level development.
- Narrow‑vein geometry will favour highly selective mining methods (e.g. cut‑and‑fill, resue, narrow longhole).
Our Take
Alkane Resources has been steadily building a Victorian antimony–gold pipeline, with this Costerfield hit following its June 2026 start of diamond drilling at the historic Nagambie mine under an earn-in, signalling a multi-asset strategy in the state rather than a single discovery play.
With Alkane’s recent record quarterly net profit of $93 million and cash, bullion and listed investments of $374 million from its Tomingley operations, the company appears well funded to rapidly follow up high-grade intercepts at the Cuffley Lode without needing near-term external capital.
Gold–antimony combinations feature in only a small subset of the 1301 Mining stories and 423 keyword-matched pieces in our coverage, so Costerfield’s grades position Alkane in a relatively niche but strategically important space given antimony’s critical mineral status and limited non-Chinese supply.
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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