A maiden drilling program by Green Critical Minerals at the Boulia copper-gold-molybdenum project in northwest Queensland has confirmed the presence of porphyry intrusions and skarns concealed beneath younger cover in the Georgina Basin.

The work aimed to validate Green Critical’s geological interpretation, developed through 3D remodelling of publicly available magnetic and gravity data, which was suggestive of an extensive concealed belt of prospective porphyry intrusions and skarns within the Georgina Basin sediments.

The company said the program substantiated that hypothesis and marked a significant milestone for its exploration strategy.

Drill hole results

The four-hole program marked the first time veined intrusions and associated alteration systems have been confirmed in the basin and indicated the potential for an expansive new exploration frontier south of Mount Isa.

One of the drill holes recorded the highest sulphur content of the program, correlating with consistent, detectable gold values and peaks in silver, copper and lead.

Sulphur is essential for the formation of metal-rich mineral deposits and aids in the precipitation and concentration of metals.

Iron oxide zone

Another hole intersected an iron oxide (hematite-magnetite) skarn-porphyry zone with elevated copper, silver and zinc levels over a significant 106-metre interval.

These values are believed to align with the geological model and confirm the presence of mineralisation at target depths.

A third hole recorded gold from 276m to 291m and 253m to 256m depth, accompanied by peaks in copper and lead.

The most notable result was the correlation between the highest gold content and a peak in tellurium, suggesting the potential for gold-telluride mineralisation.

Large deposit

Green Critical said Boulia’s mineral system showed potential to host a large metal deposit, particularly where iron oxide mineralisation extends into sulphide-rich zones within porous host rocks.

“The confirmation of veined intrusions and alteration systems in the Georgina Basin validates our geological interpretation and underscores the potential for this region to become a significant new exploration district,” the company said.

“With the identification of porphyry intrusions and skarns, Boulia’s exploration achievements represent a major validation of our geological interpretation and pave the way for enhanced exploration efforts.”

Area of interest

The Boulia project comprises two granted exploration permits and three permit applications over an area of 1,597 square kilometres.

The region has recently become an area of exploration interest for copper, gold and base metals.

Large projects are being developed in the area by Anglo American, Sandfire Resources and Rio Tinto.