Estrella Resources looks to be tapping into the deeper potential of its Carr Boyd nickel discovery in WA, with drilling intersecting a broad zone of sulphide mineralisation at around 590 metres down-hole. The drilling confirms the down-dip extensions to the previously intersected T5 mineralisation, with other recent intersections including 3.7m at 1.14 per cent nickel and 0.74 per cent copper from 516.8m depth.
Estrella’s exploration program across the Carr Boyd Intrusive Complex continues to delineate sulphide mineralisation associated with the ultramafic stratigraphy. Drilling 150m along strike from the T5 discovery holes has intersected significant nickel sulphide mineralisation which remains open at depth.
Drill hole CBDD041 intersected 8.25m of disseminated to blebby sulphides from around 298m down-hole, whilst the company’s first hole of the new year, CBDD042, encountered an impressive 19m of disseminated to net textured sulphides from 595m. The increase in mineralised width in hole CBDD042 hints that the sulphide lodes might be belling out at depth, which the company says is not uncommon in intrusive-related nickel-copper ore systems.
Additional drill results from exploration along the southern strike extents of the T5 discovery show the nickel-copper mineralisation extending down-dip. Drill intercepts include 8.05m at 0.81 per cent nickel and 0.48 per cent copper from 516.8m down-hole and 5.4m at 0.85 per cent nickel and 0.72 per cent copper, hosting 1.95m at 1.35 per cent nickel and 1.37 per cent copper from 505.6m down-hole.
The ongoing success of the drilling program at Carr Boyd is unveiling the potential scope of the sulphide system at the discovery, with preliminary mapping and modelling showing mineralisation stretching along more than 1,200m of strike and extending to more than 550m below surface. An interpretation of the latest drill results also shows the ore system remains open at depth, according to the company.
Estrella Resources Managing Director, Chris Daws said: “We have started the year with a fantastic result in the very first hole of 2021, significantly expanding the vertical extent of nickel and copper sulphide mineralisation at T5 to over 500m. Our understanding of the immediate geological environment is becoming clearer as we continue our hunt in earnest for the source of the massive nickel and copper sulphides at Carr Boyd.”
The company’s ongoing diamond drilling is providing an abundance of geotechnical information which is helping to guide and target the developing exploration program. Modelling indicates the nickel sulphide mineralisation across the T5 discovery zone has been emplaced along the basal contact between the pyroxenite cumulate ultramafics and the underlying basaltic bedrock.
Nickel mineralisation at T5 appears to have been squeezed and remobilised along this ultramafic-mafic contact forming the nickel sulphide lodes, however these ore positions are further complicated by flat lying faults that offset the mineralisation shifting the sulphides further east at depth, complicating drill targeting.
Estrella says this new understanding of the structural and lithological controls on mineralisation explains a lack of sulphides in earlier holes drilled further along strike, which appear to have drilled over the top of the mineralised contact and will assist in the positioning of future drilling. The company is also utilising down-hole electromagnetics, or “EM” to light up the various conductive sulphide targets at depth in order to better target the proposed drill locations in three-dimensions.
Curiously, whilst the T5 sulphide nickel-copper discovery lies along a defined stratigraphic contact, the nearby Carr Boyd mine ores sit around 170m above this contact, suggesting that the company may need to revisit the mine mineralisation as a part of its evolving exploration program.
The Carr Boyd nickel sulphide project is located 80km north-northeast of Kalgoorlie in Western Australia’s highly mineralised Eastern Goldfields. The company’s tenure covers the famed Carr Boyd nickel mine and its surrounds, which was discovered in the 1960s and operated by Western Mining. The ore body was mined between 1973 and 1977 producing around 200,000 tonnes of ore grading at 1.43 per cent nickel and 0.46 per cent copper.
Despite a number of junior explorers tinkering in the region over the intervening years, searching for both nickel and gold, it is Estrella’s focused and systematic exploration program that has unearthed the deep-seated T5 nickel sulphide system along strike from the original Carr Boyd mine. Better intercepts from the company’s discovery program have included 20.1m at 1.02 per cent nickel and 0.66 per copper from 368.5m and 13.9m at 1.06 per cent nickel and 0.38 per cent copper from 431.6m.
With the company’s diamond drilling program continuing to intersect nickel sulphide mineralisation providing a wealth of geological information, Estrella is now looking to expand its exploration program beyond its T5 discovery and apply its new-found knowledge across the Carr Boyd Intrusive Complex in order to begin uncovering the true potential of this nickel and copper-rich terrane.
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