The Tunkillia Project is located ~70m S/SE of the Tarcoola Project on a ~1,285 square kilometre tenement package which hosts a 965koz Au JORC (2012) Mineral Resource Estimate at its cornerstone 223 Deposit (26.1Mt @ 1.15 g/t Au).*
Tunkillia is a large scale exploration project hosting some ~50km strike of the highly prospective Yerda and Yarlbrinda Shear Zones. These shears are major structures several kilometres wide and are analogous to major Kalgoorlie Shear Zone systems. The project area has been historically under-explored with very little drilling outside of the 223 Deposit during the past ~20 years.
Tunkillia holds significant potential for large-scale extensions and discovery of new mineralisation. The 223 Deposit is ~2.5km long and open to depth and along strike, with the host structure extending a further ~7km north and ~7km south. Mineralisation is evident on both the western and eastern demagnetised margins of the Yarlbrinda Shear, which host several advanced satellite targets in the immediate vicinity of the 223 Deposit.
Upgraded 223 Deposit Model
The 223 Deposit hosts broad, continuous mineralisation which is potentially amenable to cost-efficient large-scale open pit operations. The mineralisation is unconstrained and open to depth extension, with very little drilling deeper than 200m depth and an average historical drill hole depth of less than 80m.
Recent comprehensive remodelling with higher outer wireframe cut-off grades and proper sub-domaining of the mineralisation has produced an improved geological model with lower internal dilution and higher overall grade. The Company has also interpreted multiple higher-grade (up to +5 g/t Au) zones where mineralisation is bounded at the footwall contact by mafic dykes.
These findings provide insights which may help identify extensions, additional high-grade zones and new regional mineralisation, and also provide opportunities to optimise potential future mining methods and plans.
Immediate Camp Scale Opportunity
Tunkillia hosts multiple advanced ‘Line of Lode’ targets on the western and eastern demagnetised margins of the Yarlbrinda Shear, located in the vicinity of the 223 Deposit. The 223 Deposit was discovered during 1996, and since ~2000 the majority of drilling in the area was focused on infill drilling of that deposit.
However, shallow historical drilling indicates the presence of extensive mineralisation and has identified multiple local satellite targets. This historical drilling has not previously been followed up, and provides an excellent opportunity to leverage historical data to discover and convert new zones of large-scale mineralisation into additional Mineral Resources in close proximity to the 223 Deposit.
Barton has completed a detailed target ranking and has identified Area 51 and Area 191 as priority drill-ready targets. The Company will also undertake additional geophysical analyses to further refine its local and regional structural interpretation, and target potential regional analogues for future evaluation.
Untapped District Scale Potential
Historical exploration at any scale has generally been limited to only a small northern portion of the Yarlbrinda Shear in the vicinity of the 223 Deposit. Numerous southern prospects have been identified by previous explorers, but the majority of the shear zone has not received any modern or systematic exploration.
The Company has identified initial regional targets of interest and will undertake additional geophysical analyses to general a combined structural, geophysical and geological model and refine priority drilling targets. In particular, Barton will target regional analogues to the 223 Deposit area, as well as areas containing changes in shear orientation and intersecting regional structures along the western and eastern demagnetised zones.