Gold Fields and Great Southern Mining are sharpening the diamond bits in preparation for a return to the duo’s expansive Edinburgh Park gold grounds in north Queensland, with diamond drilling set to begin once the wet season wraps up in May.
The project is being explored under a joint venture (JV), with Gold Fields earning up to a 75 per cent interest by spending $15M on exploration.
The highly anticipated program will kick off at the impressive Mt Dillon target, where geophysical surveying has outlined a tantalising induced polarisation (IP) chargeability anomaly lurking beneath a preserved silicified lithocap.
Lithocaps are zones of resistant, silica-rich alteration formed at shallow depths, typically above porphyry copper-gold systems. These hardened structures tend to remain wholly or partly intact, rather than being eroded away.
These characteristic features are often drawcards for mineral explorers. They often form prominent, hard ridges or cliffs, exposed at surface and frequently feature strong red-brown staining due to the oxidation of abundant iron sulphides. They may be massive, extend laterally for many kilometres and can exceed 1km in depth.
Gold Fields believes Mt Dillon’s IP anomaly could be an intrusive related gold system and represents the JV’s most advanced drill target generated at the project to date.
The vast Edinburgh Park project is a true province‑scale landholding. It is centred 75km west of Bowen in Queensland and covers 1565 square kilometres.
The region is renowned for its epithermal and intrusion-related major gold deposits, including the 10-million-ounce Ravenswood mine, Mount Leyshon with three million ounces of gold and the Mount Carlton gold project, host to two million ounces.
Great Southern Mining managing director Matthew Keane said: “2026 is shaping up to be an exciting year for the Edinburgh Park JV. Multiple targets within Edinburgh Park display the attributes required for large-scale gold systems, including deep-seated structures with pervasive hydrothermal alteration from surface and coincident geochemical anomalies.
Diamond drilling undertaken last year tested several targets across the northern part of the project, including at Leichhardt Creek, Molongle and Megan Veins. Historic high-grade gold anomalism from surface sampling recorded 5.27g/t gold at Molongle and up to 10g/t gold at Megan Veins.
While those first‑pass holes did not define economic mineralisation, they did pick up extensive quartz‑sulphide veining and pervasive hydrothermal alteration. That evidence has reinforced the likely presence of multiple big mineralised systems, sharpening Gold Fields’ focus on the most compelling targets yet to be tested by drilling.
In this context, the Mt Dillon target, 4km northeast of Molongle, is considered a prospective primary intrusive centre. The gradient array and pole‑dipole IP geophysical surveys defined a deep‑seated chargeable response between 200m and 300m metres below surface, coincident with strong alteration at surface, including the lithocap.
Geological mapping shows widespread argillic-style low-temperature alteration which has converted some key rock-forming minerals to distinctive clays over several square kilometres. The style is recognised as a critical indicator of mineral deposits and is often found in the marginal zones of porphyry copper or epithermal gold-silver deposits.
Drilling at Edinburgh Park is being conducted in tandem with Great Southern’s increased exploration push across its broader portfolio, underpinned by a recent $4.6M placement completed in March.
The capital raising has left the company fully funded to pursue exploration across both its joint venture ground in Queensland and other wholly owned gold projects in WA.
The first five planned holes at Mt Dillon are set to punch straight into the core of the geophysical anomaly and determine whether the alteration system extends into a mineralised intrusive at depth.
The joint venture is also planning additional geophysical and geochemical surveys across the project area to continue building its pipeline of large‑scale drill targets.
With funding in place, a major joint venture partner and a queue of high-impact targets lined up for drilling, Gold Fields and Great Southern Mining look well placed for a notable discovery at the compelling Mt Dillion geophysical target, as Edinburgh Park edges closer to a possible defining phase for the project.
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By Doug Bright
