Exploration Risks and Rewards: Can St Barbara Unlock Southwest Tatau’s Hydrothermal Potential?

• Gold in soil anomalies extended to 7.3 km² on Southwest Tatau Island
• Rock chip samples reveal high-grade gold up to 22.5 ppm Au
• Mt Tiro and Mt Siro-Seraror soil anomalies cover large target areas
• Widespread alteration and sulphides indicate a major hydrothermal system
• Trenching and reconnaissance drilling completed; assay results pending

Exploration Breakthrough on Tatau Island

St Barbara Limited (ASX – SBM) has announced promising results from its recent exploration campaign on Southwest Tatau Island, Papua New Guinea. The company’s hand auger soil sampling program has expanded gold anomalies to cover an area of 7.3 square kilometres, a footprint comparable to the 6.9 square kilometres of gold anomalies that host the established Simberi deposits on the neighbouring island.

High-grade gold assays from rock chip samples in the Mt Siro - Seraror area have returned values as high as 22.5 parts per million (ppm), with additional significant results including 12.3, 2.0, and 1.98 ppm Au. These samples were collected within the soil anomaly and extend 150 to 450 metres north of previous historical trenching and drilling, suggesting new zones of mineralisation.

Target Areas and Geological Indicators

The Mt Tiro area also showed encouraging results, with soil samples yielding gold concentrations up to 2.39 ppm. The Mt Tiro anomaly now measures approximately 1.8 km by 0.8 km, while the Mt Siro - Seraror anomaly covers about 1.4 km by 0.7 km. These sizeable anomalies, combined with the presence of widespread alteration and elevated sulphide percentages, point to a substantial hydrothermal system beneath Southwest Tatau Island.

St Barbara’s Managing Director and CEO, Andrew Strelein, highlighted the significance of these findings, noting that the regional exploration campaign has successfully identified multiple highly anomalous zones. He emphasized the value of refining the geological understanding of the Simberi epithermal system to guide exploration efforts across the company’s tenements.

Ongoing Work and Future Plans

The recent program included 300 regional hand auger soil samples and 204 rock chip samples collected over a 6 km by 3.5 km area. Additionally, 22 trenches totaling 1,483 metres and 17 reconnaissance reverse circulation (RC) drill holes covering 1,020 metres were completed. Assay results from trenching and drilling are expected in the first quarter of the 2026 fiscal year, which will be critical to confirming the continuity and grade of the mineralisation.

Following the receipt of these results, St Barbara plans to conduct further infill and extension soil sampling, trenching, and RC drilling, particularly targeting the higher-grade gold zones identified. The company is also progressing discussions with Kumul Mineral Holdings Limited, the Papua New Guinea state nominee, toward an exploration joint venture agreement covering the EL609 and EL2462 tenements.

Strategic Implications

The expansion of gold anomalies on Southwest Tatau Island not only enhances the exploration potential of St Barbara’s portfolio but also positions the company to leverage its geological expertise developed at Simberi. The presence of a large hydrothermal system could signal the discovery of new deposits, potentially extending the life and scale of operations in the region.

Bottom Line?

As assay results from trenching and drilling loom, St Barbara’s Southwest Tatau Island project could redefine its growth trajectory in PNG’s gold sector.

Questions in the middle?

• Will forthcoming trench and RC drill assays confirm the extent and grade continuity of the new anomalies?
• How will the potential joint venture with Kumul Mineral Holdings influence exploration and development timelines?
• What are the implications of the large hydrothermal system for discovering economically viable gold deposits?