A gold-hunting partnership between Great Boulder Resources (ASX: GBR) and Castle Minerals (ASX: CDT) has detected strong pathfinder anomalism and elevated levels of the key antimony element – a key to finding orogenic gold deposits – after punching its first air-core (AC) drillholes into the Polelle project in Western Australia’s Mid West region.
GBR has a one-year option with Castle, aimed at forming a 75:25 joint venture (JV) at Polelle, requiring it to spend least $250,000 on exploration within the first year.
The company’s 45-hole, 1764m AC program tested ground in the north-west and eastern sides of the project along four lines of shallow drilling that fell within the heritage-approved zone obtained by Castle in 2022. Drilling also tested one line across a possible splay off the Albury Heath shear zone that lies on the contact area between intermediate and mafic rocks.
The drill program confirmed GBR’s targeting model and encountered strong pathfinder anomalism, with bottom-of-hole assays returning antimony values ranging from 11 parts per million to 55ppm at Lordy Bore and antimony going 12ppm in the north-west area near Bassett Bore. The antimony was also accompanied by elevated levels of arsenic, copper, bismuth, tellurium, molybdenum and lead.
Management says some anomalous values were associated with carbonaceous black-shale, which can show elevated pathfinder elements due to scavenging by the carbon. However, it noted that a complex sequence of mafic-to-intermediate rocks within proximity also demonstrated elevated levels and will now be targeted for further exploration.
Antimony is one of our key pathfinder elements for orogenic gold deposits and it confirms we’re inside the mineralised system. We are planning a heritage survey shortly to clear the priority targets prior to our next drilling program.
Great Boulder Resources Managing Director Andrew Paterson
Once the heritage and program of works (POW) approvals are in place, GBR is planning a second round of AC drilling to help provide an updated assessment for the potential at Polelle.
The company has already paid $50,000 to Castle by way of share-scrip, based on its 30-day volume-weighted-average price (VWAP), to secure its one-year option.
Castle also packaged up its promising Wanganui gold project as part of the deal. It means GBR is able to exercise its option on the two projects by paying Castle an additional $100,000 in scrip, valued at its 30-day VWAP.
Once the option is exercised, the pair will form the JV.
GBR may also extend the option for an additional one year, rather than exercise it, by paying a second fee of $100,000 in the company’s share-scrip, in addition to a further commitment to spend $400,000 during the second option period.
Once a JV is formed, if Castle elects not to contribute, its interest will dilute and if it drops below 10 per cent, it will automatically convert to a 1 per cent net smelter royalty (NSR). There is a pre-existing 1 per cent gross-revenue royalty (GRR) over both gold projects under the option.
The Polelle project sits 8km south-west of GBR’s Side Well gold project and 7km east of Westgold Resources’ Bluebird Mine. The Side Well project, with its Mulga Bill and Ironbark deposits, comprises a mineral resource of 7.45 million tonnes at 2.8 grams per tonne gold for 668,000 ounces.
Westgold recently revealed an updated mineral resource for the Bluebird-South Junction deposits of 6.4 million tonnes at 3.1g/t gold for 827,000 ounces.
The Wanganui project sits about 5km west of Westgold’s large tenement holding in the area, with previous reverse-circulation (RC) drilling by Castle intersecting 3m at 18.66g/t gold from 62m and 8m at 4.1g/t from 66m. Its Wanganui North and South pits were previously mined by St Barbara in 2002, producing 5701 gold ounces at a grade of 1.62g/t.
With close proximity to high-performing gold operations, the partnership’s two projects now need to be fully tested by the drill bit to reveal what lies within its ground.
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