North Stawell Minerals (ASX:NSM) has uncovered promising extensions to gold mineralisation at its Caledonia Prospect through a detailed 412-sample surface geochemistry program, highlighting untested anomalies and reinforcing the site’s high-grade potential.
- 412-sample geochemistry reveals two new target extensions
- Untested 400m bismuth-tungsten anomaly linked to gold systems
- Caledonia hosts a 600m drilled gold trend with assays above 1g/t Au
- Targets align with the 3.6 km Darlington-Caledonia gold trend
- Further drilling and geophysical surveys planned to test anomalies
Geochemistry Uncovers Concealed Gold Targets at Caledonia
North Stawell Minerals (ASX:NSM) has advanced its exploration narrative in Victoria with a 412-sample multi-element surface geochemistry program at the Caledonia Prospect, part of its North Stawell Project. The survey delineated two potential extensions to the known mineralisation: a northwest-trending fault-offset continuation along the margin of a deeper basalt and a north-trending arsenic anomaly. These findings add fresh dimensions to a 600-metre drilled gold trend that already boasts assays exceeding 1g/t Au and local highs up to 12 g/t Au.
Of particular interest is a roughly 400-metre-long bismuth anomaly accompanied by tungsten and weak gold signals on the eastern side of the basalt. This anomaly remains untested by drilling but is noteworthy given bismuth and tungsten’s association with gold mineralisation in the region, such as at NSM’s Darlington West Prospect just 2 kilometres south.
Caledonia’s Geological Setting Mirrors Historic Gold Systems
Caledonia lies within a 3.6-kilometre Darlington-Caledonia trend, a key exploration focus for NSM in 2026. The trend is structurally controlled by a deeper basalt, analogous to the Magdala Basalt that underpins the multi-million-ounce Stawell gold deposit 8 kilometres to the south. Caledonia’s mineralisation is interpreted as “Mariners-type,” characterised by brecciated, gold-bearing quartz veins above the basalt roof, similar to the historic Mariners’ Reef which produced close to one million ounces at an extraordinary grade of 28 g/t Au.
Bill Reid, NSM’s Executive Director, emphasised the prospect’s allure: “Caledonia is masked by very thin cover preserving significant potential for shallow gold mineralisation. The mineralisation is open along strike and down-dip, and the geochemistry program identifies possible extensions that could expand our understanding and footprint along this high-grade trend.”
Subtle Gold Signals and Strong Arsenic Anomalies
The geochemical survey, which assayed 48 elements including gold and arsenic, revealed subtle gold anomalies that drop off beneath sediment cover but remain coherent above previous drill intersections. Elevated gold grades appear to have shifted approximately 100 metres west, suggesting a fault displacement supported by geophysical data, creating a new untested 200-400 metre gold anomaly at surface.
Arsenic anomalism, often a pathfinder element for gold, showed mixed results. While weakly marking the known northwest-trending mineralisation, a north-trending arsenic anomaly traced over 300 metres to the north gained strength, coinciding with historic air core drilling that intersected low-grade gold. This arsenic anomaly could represent a new mineralisation system extension warranting further investigation.
Robust Historical Data and Rigorous Sampling Methodology
The announcement details comprehensive sampling and assay protocols, including 25m x 200m grid spacing for soil samples, assayed at ALS laboratories with stringent QAQC procedures. Historic drilling data underpinning the current interpretation includes 22 air core holes, four diamond holes, and four reverse circulation holes, collectively confirming the presence of high-grade gold mineralisation along the Caledonia trend.
NSM’s contiguous 445 km2 landholding along the Stawell corridor benefits from a rich exploration history dating back to the 1970s, with multiple companies contributing to the geological understanding. The current strategy leverages this legacy while focusing on shallow, high-grade targets beneath thin cover, a critical factor given the region’s complex geology.
Next Steps: Drilling and Geophysical Surveys to Test Targets
Looking ahead, NSM plans to design drilling programs to test these newly identified anomalies, particularly the fault-offset gold trend and the bismuth-tungsten anomaly. The shallow nature of mineralisation at Caledonia suits air core drilling, complemented by potential induced polarisation (IP) surveys to better delineate subsurface structures. These efforts aim to expand the known high-grade footprint and refine the geological model along the Darlington-Caledonia trend.
This update builds on NSM’s ongoing exploration momentum in Victoria, where recent drilling programs at Darlington and Caledonia have reinforced the potential for multi-million-ounce gold systems analogous to the historic Mariners Lodes near Stawell. The company’s methodical approach combining geochemistry, geophysics, and drilling continues to unlock promising targets within a well-endowed gold province.
Bottom Line?
Caledonia’s new geochemical targets open avenues for expanding NSM’s high-grade gold footprint, but drilling results will be pivotal to validate these conceptual anomalies.
Questions in the middle?
- Will upcoming drilling confirm the fault-offset and bismuth-tungsten anomalies as extensions of high-grade gold mineralisation?
- How might the north-trending arsenic anomaly reshape the geological model for Caledonia and the broader Darlington-Caledonia trend?
- What impact could these discoveries have on NSM’s resource base and exploration priorities in the Stawell corridor?