Drill results from De Grey’s Diucon and Eagle deposits at Hemi – part of the Mallina gold project in the Pilbara – have returned major strike and depth extensions.

The 9.5Moz Hemi deposit underpins the 11.7Moz Mallina project, where first production is pencilled in for 2026.

And now it looks like the Diucon and Eagle deposits could enhance the future resource growth and production potential at Hemi, with the new results not included in the June 2023 update to the Hemi Mineral Resource Estimate (MRE).

New diamond drilling results at Eagle include:

  • 26.9m at 10.6g/t gold, including 3.5m at 16.7g/t gold and 3m at 54.7g/t gold, and 15.2m at 1.9g/t gold;
  • 14.0m at 6.0g/t gold, including 1.0m at 73.9g/t gold;
  • 37.1m at 3.4g/t gold, including 3.9m at 15.1g/t gold; and
  • 11m at 2.7g/t gold, including 3m at 8.3g/t gold.


Drilling along the Diucon Thrust has extended relatively shallow mineralisation up to 800m west of the Diucon MRE, with results including:

  • 6.4m at 2.9g/t gold;
  • 19m at 2.0g/t gold;
  • 20m at 2.2g/t gold, including 5m at 5.8g/t gold and 6m at 2.9g/t gold); and
  • 8.8m at 4.8g/t gold, including 4m at 8.9g/t gold.


The results substantially extend mineralisation by at least 250m along strike and 250m down plunge at Eagle and by up to 800m along strike to the west at Diucon, with mineralisation at Eagle and Diucon open at depth and down plunge to the west.


Open pit and underground mining potential

De Grey Mining (ASX:DEG) says the results provide the potential for increased scale of the planned Diucon-Eagle open pits as well as enhancing underground mining potential.

“Following completion of resource definition drilling to support the Definitive Feasibility Study (DFS), the focus has shifted to exploration drilling,” general manager exploration Phil Tornatora said.

“This is already paying dividends, with significant extensions to mineralisation at depth at Eagle and along strike at Diucon.

“In addition to potential resource increases, deeper drilling at Hemi will support early conceptual studies into potential underground mining in the future.

“The shallower Diucon extensions have the potential to result in an expansion of the Diucon-Eagle open pit shell outline”


Exploration drilling continuing and DFS underway

Current exploration at Hemi includes RC drilling along the Antwerp trend just west of Eagle, targeting additional resources, with RC drilling also planned next for the Brolga South area.

Diamond drilling is targeting Eagle extensions, in addition to high grade zones in the east of Crow.

In addition, the DFS is due for release in the current September 2023 quarter and will be based on the June MRE released on 16 June 2023 which incorporated assays from drilling up until 7 March 2023.

These new extensional drill results therefore represent further upside to the DFS outcomes.

De Grey says there is potential for the extensions to be included in future open pit and underground mining plans.



This article was developed in collaboration with De Grey Mining Limited, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.