De Grey has reported high gold recoveries from metallurgical testwork at the Falcon and Crow zones at the Hemi discovery within the Mallina gold project in the Pilbara. 

Five separate (two oxide, three primary) composites achieved an average recovery of 94.2% at the Falcon zone, with the average head grade at 1.4g/t gold – and an average tail grade of less than 0.1g/t.

At Crow, the average metallurgical recovery was 96.8% on five separate composites of primary mineralisation.

The average head grade was 2.0g/t gold, ranging from 1.3g/t to 3.8g/t, with some samples taken from the higher-grade McLeod lode at Crow.

And the overall average tail grade was less than 0.1g/t.

Encouraging gold recoveries

De Grey Mining (ASX:DEG) managing director Glenn Jardine said the results are consistent with the positive results previously achieved from the Brolga and Aquila zones at Hemi.

“The new metallurgical testwork from the Falcon and Crow deposits at Hemi continues to demonstrate encouraging gold recoveries,” he said.

“The consistently low tail grades achieved in testwork at Hemi will be carried through into project studies and evaluations.”

The company considers the tail grades achieved at Falcon and Crow of less than 0.1g/t Au very encouraging.

Further testwork will now be undertaken at head grades that are in line with expected process plant feed grades for the scoping study.

Further testwork planned to optimise recoveries

Testwork is also continuing across all deposits at Hemi and will include Diucon and Eagle, where diamond core samples are becoming available with extensional drilling at depth.

The company considers mineralisation at Diucon and Eagle to be similar to the previously tested zones at Hemi.

“Metallurgical testwork continues to provide confidence in the multiple pathways available to achieve high gold recoveries from Hemi and the regional deposits across the Mallina gold project,” Jardine said.

“Each of the three potential oxidation processes (pressure oxidation, biological oxidation and Albion) have delivered high gold recoveries and will be carried forward into future studies.

“Further testwork and trade off studies will optimise capital, operating costs, recoveries and operability to enable the company to select the preferred sulphide oxidation route for the project.”




This article was developed in collaboration with De Grey Mining, 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.