A dipole-dipole induced polarisation survey (DDIP) was conducted across part of the project as part of a work program under the JV with the mid-tier gold producer.
When combined with recent soil and rock-chip geochemical survey results, the DDIP highlighted several coincident geophysical-geochemical targets with an intrusive related gold (IRG) and pathfinder (copper-lead-zinc-silver-arsenic-antimony) signature.
Two priority targets
The two priority-1 (P1) high-ranking targets, Tatooine and Naboo, are near the Horn Island 500,000-ounce inferred gold resource.
Managing director Andrew Buxton said: “It's encouraging to see these significant IP anomalies lining up with our previously announced surface geochemistry.
"With our JV well ahead of schedule in terms of planned spending, the next phase of our Horn Island partnership looks very exciting.”
Schematic E-W cross-section of the depth modelled P1 DDIP chargeability target Tatooine.
Correlation with mapping
The P1 chargeability targets also correlate with geologically mapped surface vein trends and soil and rock chip gold anomalies with associated IRG pathfinder element anomalism.
Independent geophysical consultant interpretations indicate that DDIP chargeability and conductive anomaly responses are consistent with the potential presence of sulphide minerals.
The DDIP survey totalled 28.4 survey line kilometres on 15 NE-SW orientated traverse lines spaced 200 metres apart.
Four of the survey lines extended across the Horn Island gold resource and the survey defined an IP chargeability anomaly that corresponds with this resource.
Promising sulphide target
This provides encouragement that the larger IP chargeability anomaly extending to the northwest represents a promising sulphide target.
Several lower-ranked chargeability anomalies were also identified across the survey area and are typically defined by narrower or shallow DDIP chargeability anomaly trends.
DDIP chargeability anomalies at 180mbs generated from 3D inversion modelling, with outlines of combined surface soil and rock chip gold target areas.
These anomalies often display a significant strike extent and correlate with surface vein structural trends, or aeromagnetic demagnetised structural zones, which are interpreted to represent structures that acted as primary fluid zones for potential gold mineralisation.
Although these targets appear narrow, shallow or display limited strike extent, they may be of importance.
The DDIP survey was completed by Fender Geophysics with data processing and preliminary interpretations completed by independent geophysical consultant Resource Potentials Pty Ltd.
Considering further work
Alice Queen and St Barbara are now considering drilling programs to test these P1 targets.
Due to the success of the initial survey, a step-out DDIP survey to cover other gold targets at Horn Island may also be considered.
Horn Island St Barbara Joint Venture and excluded areas.
St Barbara achieved the year-1 minimum expenditure requirement of $500,000 in February 2020.
The JV entitles St Barbara to earn 70 per cent of areas outside of the excluded zones by spending $4 million over three years.
Excluded zones are the existing inferred resource, historic mine infrastructure which includes certain road areas and decant water dam, historic waste dumps, low-grade ore stockpiles, ROM pad and all alluvial gold across Horn Island to a depth of 5 metres below surface.