Alkane Resources (ASX:ALK) will commence development towards the Brunswick South deposit this quarter after drilling confirmed gold and antimony mineralisation 200m from existing underground access at its Costerfield operation in Victoria.
The company completed 91 holes totalling 28,421m since its previous update in October 2025, with drilling identifying a ‘high-grade’ connection between the recently discovered gold dominant zone at depth and historical surface workings.
Assay highlights from the Brunswick South vein include 50.1 grams per tonne gold (Au) and 26.2% antimony (Sb) over 2.17m in hole BD468, 109.9g/t Au and 3.1% Sb over 0.65m in BD433, and 50.2g/t Au and 33.3% Sb over 0.86m in BD424.
The deeper gold-dominant Kiwi zone returned 25g/t Au over 1.7m in BD513, with geological interpretation indicating the mineralisation setting is similar to the currently mined Youle deposit.
Managing Director Nic Earner says focused extension and infill drilling over the previous year has produced highly encouraging results.
“This newly defined deposit not only contains pockets of high gold endowment, but critically a significant quantity of antimony. Excitingly Brunswick South can be brought online without extensive access requirements as it is situated 200m from existing development,” Earner says.
Alkane says drilling identified two main economic zones — an upper shoot of ‘high-grade’ antimony–gold mineralisation reaching from 80m below surface down to around 280m depth with approximately 200m panel height, and a lower panel of gold-dominated mineralisation with 400m strike length located below the Penguin Fault.
According to the company, drilling supports confidence in grade continuity, with a general trend from antimony-rich intercepts in the upper deposit levels transitioning to more gold-dominant mineralisation approaching the Kiwi Zone.
The company also intercepted parallel veining approximately 200m west of Brunswick South, with follow-up drilling scheduled to commence after an intercept of 8.40g/t Au and 1.30% Sb over 0.32m in hole BD475.
Brunswick South is located 400m south of the previously mined Brunswick vein within the Costerfield gold-antimony field, which has operated continuously since 2006. The deposit sits at the apex of the Costerfield Dome between the Augusta and Youle deposits, with mineralisation hosted by a vertical shear within the hinge of the Brunswick Anticline.
Alkane says it will integrate the drilling results into the Costerfield mine schedule, with capital development to access the area scheduled for the September quarter of 2026. The company also plans to release an updated mineral resource estimate and maiden ore reserve later this year.
According to Alkane, future drilling will target further down-dip extensions on the Kiwi Fault structure below 800m depth, the gap between Brunswick and Brunswick South deposits, and southern extensions where hole BD407 returned 9.40g/t Au over 0.30m at the program’s southernmost test point.
Write to France Pinzon at Mining.com.au
Images: Alkane Resources
