St Barbara Limited ('St Barbara' or the 'Company') (ASX: SBM) is pleased to report on the latest successful regional surface sampling and drilling program at southwest Tatau Island, Papua New Guinea (EL609).
Highly anomalous gold results have been returned from the hand auger soil sampling program that extends the southwest Tatau Island +0.1 ppm gold in soil anomalies to an area covering 7.3 km2. In addition, high grade gold in rock chip samples were returned from within the soil anomalies.
St Barbara Managing Director and CEO Andrew Strelein said: 'This first substantial regional exploration campaign at Tatau Island, the neighbouring island to Simberi, has rewarded us with multiple highly anomalous rock chip and soil samples that extend the anomalous areas around Mt Tiro and at Mt Siro - Seraror in particular. After focusing our attention in FY24 on the successful Simberi resource development and infill conversion program the team are now broadening their efforts to the regional program and following up opportunities identified in previous campaigns.' 'The Company believes that the presence of widespread alteration and elevated sulphides within the southwest Tatau Island supports the interpreted presence of a large hydrothermal system and demonstrates the exploration potential of the area. The fine tuning of our interpretation of the very large Simberi epithermal system is invaluable to the development of the thinking on exploration across EL609 and EL2462.'
Southwest Tatau Island Program
A regional exploration work program of surface sampling and RC drilling was completed over a portion of southwest Tatau Island between September 2024 and April 2025. The program included hand auger soil sampling, rock chip sampling, trenching and reconnaissance RC drilling. The soil and rock chip sampling was conducted over an area of southwest Tatau Island measuring 6 km by 3.5 km: 300 regional hand auger soil samples were collected on a staggered grid at 200 m by 200 m spacing utilising a manual hand auger to provide a continuous soil profile down to a depth of between 1 m and 2.2 m depth (average 1.8 m). Soil profiles were documented and a sample taken for analysis from the upper portion of the 'C' horizon when intersected or the lower 'B' horizon when not reached, and 204 rock chip samples were collected from available outcrop, sub-crop or proximal float typically located in creeks, cliffs and access tracks.
The current epithermal gold deposits located within the Simberi Mine Lease 136, eastern Simberi Island, are all located within a +0.1 ppm gold in soil geochemical anomaly. The +0.1 ppm gold in soil anomalies on the neighbouring eastern Simberi Island that host the Simberi gold resources within ML136, covers an area of approximately 6.9 km2 and has an approximate 5 km by 2.5 km footprint. In comparison, the +0.1 ppm Au gold in soil anomalies on Tatau Island cover an area of 10.8 km2, 7.3 km2 of which is located in southwest Tatau Island. The southwest Tatau Island +0.1 ppm gold in soil anomalies have an approximate 7 km by 3.5 km footprint. The presence of widespread alteration and percent sulphides recorded in southwest Tatau Island supports the presence of a large hydrothermal system and the exploration potential of the area. The gold assay results from the recent regional hand auger soil sampling program confirms and extends several +0.1 ppm gold in soil anomalies at southwest Tatau Island. Two main +0.1 ppm gold in soil anomalies located on southwest Tatau Island include the Mt Tiro area (measuring approximately 1.8 km x 0.8 km) and the Mt Siro - Seraror area (measuring approximately 1.4 km x 0.7 km). Several high gold-in-soil assay results (2.39 and 0.57 ppm Au) are located up to 500 m further southwest than the main areas of previous trenching and drilling. A 0.86 ppm Au in soil result was returned 250 m south of previous trenching and 500 m southeast of previous drilling. Several high gold-in-rock chip assay results (22.5, 2.0, 1.98 and 1.83 ppm Au) are located between 150 m and 450 m further north of previous historical trenching and drilling. Trenching and reconnaissance RC drill holes were also completed during the campaign. A total of 22 trenches (TATTR289 to TATTR310) were completed covering 1,483 metres for 482 channel samples. The continuous, horizontal channel samples are collected on regular 2 m to 5 m intervals along exposure in excavator access tracks and creeks.
A total of 17 RC drill holes (TTRC007 to TTRC023) were completed for 1,020 metres. Results for the channel sampling and RC drilling are expected in Q1 September FY26. Proposed further work includes: 1) follow-up 200 m by 200 m extension to the soil sampling program to close out the plus +0.1 ppm Au soil anomalies and 100 m x 100 m infill soil sampling of selected +0.1 ppm Au soil anomalies; 2) upon receipt of the assay results for recent trench sampling and reconnaissance RC drilling, further trenching and subsequent RC drilling will be completed targeting the higher grade gold results. The Company continues to work with the state nominee of PNG, Kumul Mineral Holdings Limited, towards an exploration joint venture agreement over EL609 and EL24621.
Explanatory Notes
The current epithermal gold deposits located within the Simberi Mine Lease 136, eastern Simberi Island, are all located within a +0.1 ppm gold in soil geochemical anomaly. The contour map was generated from all historical and recent soil sampling (n= 29,975). Outside ML136, extensive gold in soil anomalies (+0.1 ppm Au) are present on Tatau Island with the strongest anomaly located in the southwest. A broad copper anomaly (+250 ppm Cu) is present in the central part of Tatau Island and contains several localised higher grade (+450 ppm Cu) soil anomalies. Several smaller gold (+0.1 ppm Au) and copper (+450 ppm Cu) soil anomalies occur on Big Tabar Island. The presence of less gold and copper soil anomalies on Big Tabar Island are interpreted to be the result of reduced surface sampling as well as the presence of overlying barren volcanics that shallowly cover altered volcanics. All the deposits, apart from a portion of Pigiput deposit (at depth) are generally located well within the gold in soil (+0.1 ppm Au) anomaly. The results are overlain on a thematic map of all gold assay results from soil sampling (both new and historical combined). Coloured thematic base maps were produced in Micromine software using an Inverse distance weighted interpolation to produce a gridded colour map of soil assay values. Computed Grid cells are 40m x 40m in size with a maximum search radius of 175m and minimum samples n=1, maximum n=150. The results are overlain on a thematic map of new (this release) and all past historical copper assay results from soil sampling. The copper thematic map was created using the same dataset and interpolation parameters as for gold. The copper assay results from the recent regional hand auger soil sampling program indicates that +250 ppm Cu in soil anomaly measuring 6 km long by 4.5 km wide covers most of the central part of Tatau Island. Previous soil sampling defined several copper in soil anomalies (+450 ppm Cu) associated with recognised porphyry copper-gold targets such as Madurdur (1.1 km x 0.8 km), Daramba (1.4 km x 0.5 km), Talik North (0.6 km x 0.4 km) and Kupo (0.9 km x 0.5 km). The results are overlain on a thematic map of all gold assay results from soil sampling (new and historical). Several high gold in soil assay results (2.39 and 0.57 ppm Au) are located up to 500 m further southwest than the main areas of previous trenching and drilling. A 0.86 ppm Au in soil result was returned 250 m south of previous trenching and 500 m southeast of previous drilling. Follow-up infill and extension soil sampling, trenching and RC drilling are required in this area. Several high gold in rock chip assay results (22.5, 2.0, 1.98 and 1.83 ppm Au) are located between 250 m and 500 m further north of previous historical trenching and drilling. Follow-up infill and extension soil sampling, trenching and RC drilling are required in this area.
Contact:
David Cotterell
General Manager Business Development & Investor Relations
Email: info@stbarbara.com.au
Tel: +61 3 8660 1959
Competent Persons Statement
The information in this report that relates to Exploration Results is based on information compiled by Dr Roger Mustard, who is a Member of The Australasian Institute of Mining and Metallurgy. Dr Mustard is a full-time employee of St Barbara and has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Dr Mustard consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.
