Barton Gold (ASX:BGD) upgrades Tunkillia resource classification ahead of feasibility study
Barton Gold has reported an updated mineral resource estimate for its South Australian Tunkillia gold project following 57,653m of reverse circulation and diamond drilling, with measured and indicated gold within its May 2025 Optimised Scoping Study pit shells increasing by 14%.
The drilling was designed to upgrade resource classifications for conversion to ore reserves during the ongoing pre feasibility study.
Highlights
Total gold resources comprise 59.5Mt at 0.78g/t Au for 1,500koz, including 989koz classified as measured and indicated.
Gold inventory within the scoping study pit shells is 81% measured and indicated.
Shallow inferred resources in the AuHG and POX domains contain 36koz at 2.04g/t Au.
The pre feasibility study is targeted for completion during Q1 2027, with an upgraded silver resource estimate also expected during that period.
The revised estimate incorporates 520 drill holes completed during upgrade programs undertaken since September 2025, targeting mineralisation within the existing study designs and extensions in Southern 223 previously excluded from those pit shells.
Total contained gold compares with 1,612koz in the March 2025 estimate, following remodelling that constrains mineralisation to an optimised pit shell.
This was generated by applying a revenue factor of 2.0 to the scoping study’s A$3,500/oz shell, effectively limiting the updated resource to mineralisation economically mineable at A$7,000/oz under the study’s analyses.
Within the May 2025 pit shells, measured and indicated gold increased from 724koz to 822koz, while total contained gold changed from 1,035koz to 1,011koz.
Average grade increased from 0.82g/t to 0.83g/t, with more than 5Mt of inferred mineralisation converted to indicated and more than 5Mt of indicated mineralisation converted to measured.
The S1 and S2 pits were a particular focus for validation, with their combined contained gold moving from 365koz to 362koz and average grade increasing from 1.05g/t to 1.06g/t.
Barton Gold Managing Director Alexander Scanlon addressed the implications for development discussions.
“These results confirm a robust basis for Tunkillia’s PFS, and upgrading 151koz Au to ‘Measured’ classification provides material support for expedited conversations for project finance, as well as available low dilution funding pathways.”
Further geological analysis identified shallow higher grade zones associated with the weathered margins of a large mafic dyke.
The AuHG domain occurs in fresh mineralisation on the hanging wall, while the POX domain occupies partially oxidised mineralisation and extends closer to surface through the S1 and S2 pits.
Greater grade variability has left portions of these zones classified as inferred, despite their proximity to measured or indicated resources.
Barton has identified their conversion to higher resource classifications as a priority for potential follow up drilling.
Outside the earlier study pit shells, 6.2Mt containing 131koz is classified as indicated, with the announcement identifying potential for pit shells generated during the pre feasibility study to extend beyond the existing designs.
Silver is reported as a by product of gold mineralisation, with an inferred resource of 2,759koz.
Historically limited silver assaying means resources are not reported for Area 223N or Southern 223, and Barton intends to resample historical drilling to re estimate silver across the project.
Work supporting the next development stage includes environmental monitoring, heritage surveys, infrastructure sterilisation drilling and tailings storage studies.
Development scale, renewable energy options and camp infrastructure arrangements are also being evaluated alongside preparation for a planned mining lease application.