Tunkillia Gold Project: infill drilling upgrades the starter pit zone as Barton Gold enters Pre-Feasibility

Monday 13 July 2026

Barton Gold's latest infill drilling at Tunkillia has delivered some of the strongest results to date from the southern end of the Area 223 open pit, the zone modelled to produce the highest-grade ore during the first years of mine life. With a Pre-Feasibility Study now underway and a Mining Lease application planned, these results carry weight beyond the geology: they feed directly into the economics that will determine whether this 1.6 million-ounce deposit becomes a mine.

The result in context

The results come from Phase 2 of a roughly 40,000-metre reverse circulation drilling program targeting resource upgrades across the Tunkillia Gold Project in South Australia. This batch focuses on the southern portion of the Area 223 deposit, where broad, high-grade mineralisation sits within the footprint of the optimised open pit designed in Barton Gold's 2025 Optimised Scoping Study.

Four holes stand out from the latest release:

TKB0499: 13m @ 5.01 g/t Au from 55m, incl. 3m @ 15.8 g/t Au from 62m.

TKB0536: 17m @ 3.09 g/t Au from 100m, incl. 1m @ 36.9 g/t Au from 108m.

TKB0570: 4m @ 7.60 g/t Au from 95m, incl. 1m @ 27.2 g/t Au from 95m.

TKB0572: 27m @ 1.89 g/t Au from 33m, incl. 5m @ 5.55 g/t Au from 49m.

All four intercepts sit within the upper 100 metres of the deposit. For context, the existing resource across Tunkillia totals 62.9 million tonnes at 0.80 g/t gold for 1.612 million ounces (896,000 ounces Indicated, 717,000 ounces Inferred). The announcement also includes TKB0573 (21m @ 1.65 g/t Au from 93m) and TKB0574 (19m @ 2.87 g/t Au from 137m at end-of-hole), suggesting the mineralised system remains open at depth in parts of this zone.

The geology

Tunkillia is hosted on the Gawler Craton, one of Australia's most prospective yet historically under-explored geological provinces for gold. The deposit sits within a broad mineralised system where Area 223 contains mineralisation up to 80 to 100 metres wide, suited to high-efficiency bulk open-pit mining.

Within this broad envelope, a higher-grade zone runs approximately 300 metres along strike near the footwall, shallow in the deposit. This is the zone targeted by the current infill campaign, and it is the zone modelled to be mined first. The 2025 Scoping Study modelled the "S1" starter pit to process feed at an average grade of 1.19 g/t, roughly 45% higher than the life-of-mine average. The latest intercepts, with composite grades of 1.89 to 7.60 g/t across widths of 4 to 27 metres, sit comfortably above that modelled feed grade.

The shallow depth of these intercepts (33m to 100m below surface) places them firmly within open-pit mining range. Combined with the high-grade cores, several above 15 g/t and one at 36.9 g/t, the grade profile of the starter pit zone appears to be strengthening as the infill drilling tightens the geological model.

Project trajectory

Barton Gold commenced its Pre-Feasibility Study in June 2026 with GR Engineering, targeting completion by Q1 2027. A Mining Lease application is planned alongside the PFS. The study converts the 2025 Optimised Scoping Study into a bankable development pathway, and its economic outputs will reflect whatever the infill drilling reveals about the true grade distribution of the deposit.

The Phase 2 drilling program is well advanced, with additional assays from Area 223 still pending. The current batch covers only the southern zone of the optimised pit, so results from other sections of the deposit will follow. Any upward revision to the grade profile of the early mine life zones, the starter pit in particular, has a disproportionate effect on project economics because those are the tonnes that fund the development payback.

What this means for the sector

The Gawler Craton has long been recognised as geologically prospective but commercially under-developed relative to Western Australia's Goldfields and Murchison provinces. Projects like Tunkillia, backed by a growing resource base and advancing through the feasibility pipeline, test whether the Gawler can support a new generation of standalone gold operations.

For capital allocators watching the mid-cap ASX gold space, the pattern here is instructive. A project with 1.6 million ounces at a life-of-mine grade below 1 g/t might not command attention on headline numbers alone. When infill drilling demonstrates that the first ore through the mill runs at multiples of that headline grade across broad intervals, the starter pit economics shift in a way that changes the risk profile of the entire development.

Infill drilling tells you what you already have. Results like these tell you it might be worth more than you thought.

If your drilling program needs experienced RC geologists and field technicians from day one, Norwest Exploration and Mining Services provides contract geological and field services to exploration and mining companies across Australia.