Great Boulder Resources Ltd (ASX:GBR) has refined exploration targets at the Eastern Mafic project in WA with drilling returning increased nickel, copper, cobalt and platinum group element (PGE) grades.
Recent drilling has further improved understanding of mineralisation at the project with the platinum and palladium results having potential to provide valuable by-product credits.
The company has also received strong copper and nickel results with associated gold and PGEs at the Winchester prospect, around 40 kilometres north of Eastern Mafic and the more advanced Mt Venn project.
Great Boulder managing director Stefan Murphy said the company’s growing knowledge of the mineralised system was resulting in significantly better results with each phase of drilling.
“As we get a better handle on the controls of mineralisation we have been able to prioritise drilling areas in what is clearly an extensive mineralised province,” he said.
Murphy will outline these results as well as the company’s strategy covering the prospective Yamarna region of WA during the Proactive CEO Sessions this month in Sydney and Melbourne.
Results confirm that the Cortina prospect, 600 metres west of Zermatt and within the ‘neck’ of the intrusion, contains significant copper, nickel and cobalt mineralisation.
Elevated PGE grades
Copper, nickel and PGE mineralisation was intersected within the feeder zone, with grades up to 3.1% copper, 0.6% nickel and 0.64 g/t PGE at anomaly ML13 and 0.7% nickel, 0.15 g/t PGE and 0.08% cobalt at Ben Lomond.
Best results from recent Eastern Mafic drilling.
The elevated PGE grades are commonly associated with magmatic nickel sulphide deposits.
With copper, nickel and cobalt sulphide confirmed along the feeder zone and neck of the intrusion, exploration will now focus on these parts of the mafic intrusion.
Murphy said: “It is still early days at the Eastern Mafic but the results confirm we are closing in on the higher-grade part of the system, with our efforts now focused along the 5-kilometre-long feeder zone and the neck of the intrusion at Zermatt and Cortina.
“We have multiple conductors to test along this prospective part of the Eastern Mafic as well as conductors at depth that have been identified in DHEM modelling.”
Conductors to be assessed
These untested EM conductors along the prospective intrusion will now be assessed for drilling.
In addition, several DHEM conductors have been identified from the latest survey that require drill testing.
The new DHEM conductors will be incorporated in geological modelling that is underway.
Airborne EM over magnetic image showing intrusion target (white) and untested conductors.
READ: Great Boulder Resources makes steady progress across copper, nickel, cobalt exploration portfolio
Once the geometry of the intrusive complex and prospective host units are defined, the next phase of drilling can target basal accumulations of higher-grade nickel, copper and cobalt sulphide mineralisation.
Strong Winchester results
At Winchester, two reverse circulation holes for 388 metres were drilled, both using planned holes generated from modelled DHEM conductor plates.
Best results are:
The results confirm continuity of mineralisation previously intersected in Ausgold drilling.
Winchester airborne EM (left) and magnetic image showing target areas including Winchester target subject of recent drilling.
Murphy added: “These strong results support our belief that the Yamarna region is a large mineralised province and reaffirms our strategy of consolidating the most prospective intrusions.”
In addition to mineralisation drilled at Winchester, several more airborne EM targets have been identified.
Great Boulder is assessing these targets and designing follow-up drill programs to be implemented once the formal joint venture with Ausgold is executed.
Presenting at CEO Sessions
The managing director will address investors at the CEO Session in Sydney on Monday, November 19 and in Melbourne on Tuesday, November 20.
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Or call John Phillips on (02) 9280 0700