South Perth-based mining giant IGO has passed the $350,000 exploration expenditure threshold required for it to grab a 51 per cent slice of Buxton Resources’ promising Copper Wolf project in Arizona.
And IGO can now continue on to grab another 19 per cent interest in the joint venture (JV) project it shares with Buxton by spending a further $5 million.
The latter today confirmed the agreement for the JV, to be managed by IGO. It will include the formation of an operating committee, which will be charged with vetting and approving work programs and budgets proposed by the senior partner.
IGO has six months to advise Buxton whether it intends to sole-fund the extra $5 million worth of work, or the current share ratio for the two firms will remain.
It says last year’s diamond drillholes on the Copper Wolf project JV ground confirmed the presence of a big, mineralised porphyry copper-molybdenum system with multiple veining events and a vertical extent potentially exceeding 600m depth. Assays from the second diamond hole returned 405.38m at 0.7 per cent copper equivalent from 608.38m including 105.77m at 0.86 per cent from 700.43m.
The interval sits immediately beneath the first hole – which was the first put into in the project area since 1993 and returned 83.76m at 0.9 per cent copper equivalent from 527.91m. If the overlap between the two closely adjacent holes is combined, the result is an aggregated intersection of about 485.85m at 0.73 per cent copper equivalent.
The first hole sits next to an old 1970s Utah International hole that ended in primary porphyry copper-molybdenum sulphide mineralisation.
Further to the prospectivity of Copper Wolf overall, Buxton reported in May that its drone magnetics had identified a big cluster of north-to-east trending magnetic anomalies corresponding with mineralised porphyry dykes at its 100 per cent-owned Wolverine plot that is contiguous with its IGO JV ground.
The 1200m-by-250m cluster of magnetic anomalies coincide with north-to-east trending copper-molybdenum-rich porphyry dykes from which widespread rock-chip sampling at Wolverine returned 1.2 per cent copper and 383 parts per million molybdenum next to the drill site. That sample sat next to a previously-reported 1255ppm copper and 1160ppm molybdenum result.
Buxton says the 69.6 million-year Laramide age date on its samples confirms they are linked to the Copper Wolf porphyry system and that despite outcropping mineralisation, there has been no previous drilling in the area.
The widespread favourable rock types and their geological, geochemical and geophysical anomalism at Wolverine highlight the prospect area as a compelling porphyry copper-molybdenum target, particularly when considering its outcropping mineralisation and that remarkably, it has never been drilled.
A similar condition applies to Copper Wolf generally, as it lies in one of the most endowed copper belts in the world, but has not been subject to any serious drilling since the early 1990s. Buxton’s 2022 airborne magnetic survey was the first geophysical work undertaken at the site since the early 1960s.
Historic exploration at the project has comprised mainly wide-spaced drilling focused on shallow, high-grade supergene copper mineralisation on major fault intersections.
However, Buxton is stretching its view beyond the limits of that material and hoping its exploration will guide it towards one or more giant bulk-mineable copper-molybdenum porphyry deposits that seem to have a good chance of lurking at depth.
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By Doug Bright
