Proactive Investors - Run By Investors For Investors

De Grey Mining enhances Pilbara Gold Project potential with high gold recoveries

The ongoing metallurgical work and optimisation is likely to improve project economics.
De Grey Mining enhances Pilbara Gold Project potential with high gold recoveries
The Pilbara Gold Project is 60 kilometres south of Port Hedland

De Grey Mining Ltd (ASX:DEG) has confirmed plus-90% recoveries for different gold mineralisation types from its Pilbara Gold Project in Western Australia.

Detailed metallurgical work has been ongoing since the release of the August 2017 scoping study and has culminated in the breakthrough results achieved at Withnell, the largest resource within the project.

A simplified process flowsheet has been developed and GR Engineering Services is now refining plant design, layout and costings.

READ: De Grey Mining enters option underwriting agreement in capital management measure

De Grey technical director Andy Beckwith said the 90% recovery on the Withnell sulphide mineralisation was an outstanding improvement, making Withnell a fundamental baseload to the project.

The average indicated recoveries for mineralisation types include: plus-94% for oxide material; plus-92% for free-milling fresh material; and plus-90% for the pyrite-dominated sulphide material found at Withnell.

The high gold recoveries were maintained at a coarser grind size, substantially reducing grinding requirements and the likely associated power costs.


Simplified processing circuit

READ: De Grey Mining’s drilling confirms high-grade lithium, caesium and tantalum at King Col

Beckwith continued: “We are increasingly more confident that Withnell will also provide a long-term high-grade underground mining opportunity.

“GR Engineering are working on the plant design and costings and from this we will be re-evaluating pit optimisations and the potential to add an underground mining component.

“The simplified processing flowsheet, rapid extraction times and reduced grinding requirements, together with ongoing exploration success, point to a significantly enhanced operation.”

READ: De Grey Mining recovers carse gold and nuggets in first bulk sampling

Other metallurgical results include positive gravity yields, warranting the inclusion of a gravity circuit.

Rock properties indicate low-to-high hardness and moderate abrasion, allowing for a coarser grind size improvement.

Sulphide flotation was found to be effective on all Withnell fresh and transition sulphide mineralisation.

READ: De Grey Mining shares rise on further high-grade hits beneath Withnell gold deposit

Further test work is planned to improve De Grey’s overall knowledge of all the project’s deposits.

This work will include similar detailed comminution, recovery and sulphide flotation test work as required.

Using the newly-defined operating costs and recoveries, the company will evaluate open pit and underground scenarios and an assessment to increase plant scale is planned with mining consultants CUBE.

Additional evaluation of the Withnell underground mining potential is being progressed with remodelling of the resources below the open pit, which will be followed by mine design and costing.

Diamond drilling began at Withnell last month and the 4,000-metre program will continue through the first half of this year to increase the resources at Withnell.

View full DEG profile View Profile

De Grey Mining Ltd Timeline

Related Articles

Open pit operations have focused on Matilda
January 26 2019
Reserve expansions and a Wiluna expansion DFS are upcoming milestones.
Drilling at Gabanintha project
February 04 2019
The company expects a ‘material’ increase in vanadium resources and will also publish a base metals resource.
Copper Blow project on an Australian map
February 06 2019
Exploration is ongoing at Copper Blow where the company aims to establish a resource.
Copyright ©, 2019. All Rights Reserved - Proactive Investors North America Inc., Proactive Investors LLC

Market Indices, Commodities and Regulatory News Headlines copyright © Morningstar. Data delayed 15 minutes unless otherwise indicated. Terms of use