Sunday Creek exploration tunnel: design and geotech takeaways for mine planners
Reviewed by Joe Ashwell

First reported on Australian Mining
30 Second Briefing
Approval of a new underground exploration tunnel at Southern Cross Gold’s Sunday Creek antimony–gold project in central Victoria will allow drilling from underground rather than surface pads, targeting high‑grade shoots at depth while reducing disturbance to farmland and native vegetation. The tunnel will be driven from freehold land into the main mineralised corridor, enabling tighter drill spacing and improved structural definition of the orogenic system. For geotechs and mine planners, the shift to underground drilling will refine resource geometry, de‑risk future decline design and inform ground support regimes early.
Technical Brief
- Underground drilling from the tunnel is expected to materially shorten hole lengths compared with equivalent surface holes.
- Shorter underground holes should improve core recovery and orientation quality, aiding structural and geotechnical logging.
- Concentrating drilling underground reduces the number of surface pads, tracks and sumps requiring erosion control.
- Tunnel development will require early installation of ground support, providing in situ data on rock mass behaviour.
- Early underground access allows preliminary assessment of water inflows and potential requirements for future dewatering infrastructure.
Our Take
Antimony appears in only a small subset of the 73 Mining stories in our database, so Sunday Creek positions Victoria alongside a limited group of Australian jurisdictions with identifiable exposure to this critical mineral rather than just bulk gold plays.
Most of the 184 tag-matched ‘Projects’ and ‘Sustainability’ pieces focus on battery metals like lithium and nickel, which suggests South Cross Gold’s antimony–gold work at Heathcote could appeal to policymakers looking to diversify Australia’s critical minerals base beyond the usual battery suite.
With no other South Cross Gold items in our recent coverage, this Sunday Creek antimony and gold project effectively serves as the company’s flagship in Victoria, meaning permitting outcomes and community response here are likely to shape its social licence and access to capital for any follow-on assets in the state.
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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