Buxton Resources says a second diamond drillhole into the Dogleg prospect it shares with IGO in Western Australia’s West Kimberley region has thrown up a 2.89m hit going 4.17 per cent nickel and 0.83 per cent copper from 233.63m.
The hole drilled by IGO, Buxton’s ASX 100-listed joint venture (JV) partner, also reported 0.14 per cent cobalt in the same intercept.
The tenor of the three key metals intercepted in the second hole reflects those recorded in the JV’s maiden drillhole at Dogleg that yielded a 13.85m intercept assaying 4.35 per cent nickel, 0.34 per cent copper and 0.15 per cent cobalt from 177.34m, including 5.86m at 7.47 per cent nickel. That result triggered a $500,000 milestone payment from IGO as part of their Quick Shears JV agreement set in October 2022.
Buxton Resources chief executive officer Marty Moloney said: “These are outstanding grades for semi-massive sulphide mineralisation, particularly given the results lie outside the modelled ground EM plate. Dogleg is emerging as a particularly high-tenor nickel sulphide deposit and we are looking forward to IGO’s plans for the 2024 field season.”
The numbers from the first hole immediately flagged the possibility that high-grade massive sulphides might be lurking about 200m below surface at Dogleg. The latest results in the JV’s second probing of the target reinforce the possibility that a broader zone of high-grade semi-massive mineralisation exists, which surface electromagnetic surveying did not detect.
Importantly, Buxton says the analyses validate the pyrrhotite, pentlandite and chalcopyrite sulphide mineral identifications reported in its drill core logs.
Pyrrhotite is a magnetic iron sulphide, pentlandite is an iron-nickel sulphide and one of the most important ore minerals of nickel and chalcopyrite is a copper-iron sulphide comprising 34.5 per cent copper which is the most abundant ore mineral of copper and a major source of sulphur.
The second hole was drilled as a step-back evaluation behind the first to confirm the initial intercept and to explore for a possible down-plunge extension of the mineralisation in the first hole. It targeted a pierce point 65m further down-plunge that had been interpreted from the original moving loop electromagnetic (MLEM) conductor detected in 2022.
Management says the second hole was put in outside the limits of the modelled MLEM conductor and intersected 2.89m of semi-massive sulphide mineralisation containing more than 60 per cent sulphides, as confirmed by subsequent analysis.
Downhole electromagnetic (DHEM) surveying of the second hole acquired a strong in-hole response, which the company views as justifying additional focus and follow-up drilling outside the original MLEM conductor.
The company notes that while DHEM surveying of both drillholes has shown strong responses from sulphide mineralisation immediately surrounding each hole, it could mean that DHEM might not pick up potentially mineralised EM signatures at greater distances from the holes.
However, combining the modelled MLEM and DHEM responses indicates the possibility that the MLEM conductor may extend down-plunge. Management says later modelling of the combined DHEM surveys has produced a stronger 100m-by-125m conductor that supports the potential for down-plunge extension of mineralisation.
The Dogleg prospect is part of the company’s Quick Shears project targeting Nova-style magmatic nickel-copper sulphide mineralisation in the Proterozoic belt in the West Kimberley.
The prospect was originally identified as an area of interest, based on the interpretation of magnetic and structural data pointing to the area being in an analogous position to features associated with the Merlin nickel-copper-cobalt prospect about 40km along strike to the south-east of Dogleg.
Buxton has now scored two decent hits at Dogleg, which shows the company’s mineralisation concept has merit. With the valuable support and resources of its renowned JV partner, good targeting of subsequent holes could deliver the goods.
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By Doug Bright
