Great Southern Mining Hits 4m at 11.38 g/t Gold as Golden Boulder Strike Grows
Key Takeaways
- Hole 26GBRC035 returned 4m at 11.38 g/t Au from 45m, including a 1m spike at 29.71 g/t, with visible gold noted in the chips.
- All but four of 38 holes reported from the current program hit above 0.7 g/t Au, pointing to a consistent system rather than isolated hits.
- This release covers only the northern 1.1km of a 3.5km strike, with assays pending for another 39 holes (3,425m) across the remaining 2.5km.
- Golden Boulder is barely tested below 150m, yet shares a structure with Regis's Rosemont deposit, which has defined mineralisation to 700m.
- No mineral resource exists yet, but a second program phase follows the current one's mid to late October finish, with 18 Amy Clarke holes also awaiting assays.
Golden Boulder returns high-grade gold intercepts, including 4m at 11.38 g/t Au
Great Southern Mining (ASX: GSN) has reported assays from 18 holes (1,964m) of an ongoing ~14,000m reverse circulation (RC) drilling program at its Golden Boulder discovery in Western Australia. The best result was 4m at 11.38 g/t Au from 45m in hole 26GBRC035.
The holes confirm high-grade mineralisation from surface across the northern 1.1km of a 3.5km mineralised strike. Known mineralisation has been extended by up to 50m down dip, and high-grade mineralisation was identified on previously undrilled sections.
Consistency matters here. All but four of the 38 holes reported to date from the current program recorded intercepts above 0.7 g/t Au.
Matthew Keane, Managing Director
“These latest high-grade intercepts, in conjunction with previous results from 2025 and 2026 drilling, show that Golden Boulder is a high-grade gold discovery, mineralised from surface…”
The announcement is headlined as a move from “this is something” to “how big could this high-grade discovery be”. For you, that signals the company is now focused on scale rather than simply proving mineralisation exists.
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Standout results from the latest 18 holes
The table below lists the headline intercepts as reported in the announcement. Grades are in grams per tonne of gold (g/t Au), a measure of how much gold sits in each tonne of rock.
| Hole ID | Intercept | From depth | High-grade inclusion |
|---|---|---|---|
| 26GBRC035 | 4m at 11.38 g/t Au | 45m | 1m at 29.71 g/t Au |
| 26GBRC028 | 9m at 3.36 g/t Au | 127m | 4m at 6.77 g/t Au |
| 26GBRC022 | 2m at 7.27 g/t Au | 70m | 1m at 13.93 g/t Au |
| 26GBRC020 | 4m at 3.11 g/t Au | 74m | 1m at 11.30 g/t Au |
| 26GBRC027 | 3m at 3.05 g/t Au | 34m | 1m at 6.89 g/t Au |
| 26GBRC031 | 3m at 3.88 g/t Au | 60m | 1m at 9.49 g/t Au |
Hole 26GBRC031 also returned 10m at 1.33 g/t Au from 80m, including 5m at 2.31 g/t Au.
Visible gold was observed in RC chips from hole 26GBRC035 between 45m and 46m. The company cautions that visible gold “should never be considered a proxy or substitute for laboratory (assay) analysis”, which is why the assay figures above are the ones that count.
These assays complement earlier results from the same program, reported on 21 September 2026:
- 10m at 2.62 g/t Au from 20m in hole 26GBRC011, including 2m at 10.72 g/t Au
- 7m at 2.45 g/t Au from 41m in hole 26GBRC003, including 1m at 6.91 g/t Au
Why depth and strike length matter for investors
Understanding drill-defined continuity
RC drilling uses compressed air to bring rock chips to the surface, which are then sampled and assayed. The program’s main aim is to test whether mineralised lodes (the gold-bearing zones) continue along strike and at depth.
Continuity is what separates an isolated hit from a potential larger system. The company reports multiple stacked lodes of quartz veining with disseminated sulphides, and says continuity has been identified on many drill sections that remain open at depth.
Intercepts are reported as downhole widths, and true width is not confirmed at this stage. Pending interpretation of results, a mineral resource estimate may be undertaken at Golden Boulder in the future, but none exists today.
Depth potential
Golden Boulder remains virtually untested at depth, with few holes beyond 150m below surface. It sits on the same interpreted structure as the Rosemont deposit, which has defined mineralisation down to 700m, according to Regis Resources’ Reserve and Resource statement dated April 2026.
That is why material step-outs at depth will be the focus of the next phase of drilling.
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Duketon Belt location and what comes next
Neighbours and proximity
Golden Boulder sits in a district with established neighbours:
- 26km from Regis Resources’ (ASX: RRL) +2Moz Rosemont deposit
- 14km from Regis’ +5Moz Garden Well mine and processing facility
- On the same north-south structural trend as Regis’ Baneygo (~380 Koz) and Ben Hur (~390 Koz) mines
Proximity does not mean Great Southern holds any resource itself. The company’s 549km² Duketon Belt landholding covers ~7km of the Garden Well Trend, ~11km of the Rosemont Trend and ~8km of the Erlistoun Trend. Keane noted that to the north of GSN’s tenure, Regis has defined more than 7.5 Moz of gold on these trends.
The Golden Boulder area also has over 50 historical workings over a ~3.7km strike. Recorded production from 1900 to 1955 was 1,915 tonnes at 28.6 g/t Au for 1,761 ounces of gold.
Catalysts and timelines
Several items are in the pipeline:
- Assays are pending for 3,425m (39 holes) at Golden Boulder, within the remaining 2.5km of mineralised strike.
- Assays are pending for 2,248m (18 holes) at the emerging Amy Clarke discovery, which covers a 4.7km mineralised strike, 3km northeast of Golden Boulder.
- The current program is expected to be completed by mid to late October.
- The company plans another phase of drilling immediately after the current program finishes.
For you, that means a steady run of assay results and a new drilling phase to follow.
For readers wanting the wider context behind the current drilling, our full explainer on the largest-ever Duketon drill program sets out how the company is sequencing RC work across its discoveries and what each phase is designed to test.
Ready To Learn More About The Golden Boulder Discovery?
Great Southern Mining has returned high-grade intercepts including 4m at 11.38 g/t Au, with mineralisation confirmed from surface across 1.1km of a 3.5km strike. With assays still pending for 39 holes at Golden Boulder and 18 at Amy Clarke, the drilling pipeline remains active.
To explore the company’s Duketon Belt projects and investment potential in more depth, visit the Great Southern Mining company profile on Discovery Alert. It is a practical starting point for tracking upcoming results and the next phase of drilling.