Continues To Progress Hemi Gold Find Towards Development
De Grey Mining Limited (ASX: DEG) has achieved further positive metallurgical testwork results from its Aquila zone at the world-class Hemi gold discovery located approximately 60km south of Port Hedland in Western Australia.
Testwork at Aquila was conducted on 12 individual composites representing oxide, transition and primary mineralisation and one bulk composite comprising primary mineralisation.
The samples were sourced from the top 200vm of the Aquila zone early in the drilling programme. Additional samples of oxide, transition and primary mineralisation will be collected from the Aquila zone for further testwork as necessary and as studies progress.
Managing Director, Glenn Jardine, said the company is utilising multi-element analysis to determine mineralogical variability and the requirements to conduct metallurgical testwork based on this mineralogical variability.
He said multi-element analysis indicates that the primary mineralisation tested at Aquila to date is similar to primary mineralisation at depth.
In addition, cyanide leach testwork is being conducted on samples taken every five metres downhole for every hole drilled at Hemi. This testwork along with multi-element analysis will assist in the modelling of oxide, transition and primary mineral domains for the maiden mineral resource estimate (MRE) for Hemi proposed to be announced mid-2021.
“The new metallurgical testwork results on oxide, transition and primary mineralisation from the Aquila zone at Hemi are encouraging. These results from Aquila are consistent with the positive results previously achieved from the Brolga zone at Hemi,” Mr Jardine said.
“Our ongoing metallurgical testwork programme 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.
“Each of the three potential oxidation processes has delivered high gold recoveries for the Brolga and Aquila zones. Each of the oxidation processes will be carried forward into future testwork.
“Further testwork and trade off studies underway will enable the company to optimise the various aspects of our metallurgical testwork programme in terms of capital, operating costs, recoveries and operability.”
The company is undertaking a comprehensive metallurgical testwork programme across each of the mineralised zones at Hemi (Aquila, Brolga, Crow, Diucon, Eagle and Falcon) as well as the regional deposits of Mallina and Withnell. The other main regional deposits of Toweranna and Wingina are free milling and will be able to be treated through a conventional CIL circuit.
A full suite of metallurgical testwork has commenced on composite samples from Crow and Falcon. The same programme will be conducted for the Diucon and Eagle zones when core for testwork becomes available from diamond drilling at those zones.
Primary mineralisation comprises gold associated with sulphide particles of arsenopyrite and pyrite and minor free gold. The bulk composite was tested through the process flowsheet. The overall gold recovery achieved was 94.0%.
