Buxton Resources has secured heritage clearance to drill up to 10 holes at its 80-square-kilometre Centurion project in Western Australia’s West Arunta region in its search for major iron oxide-copper-gold (IOCG) targets.
The company says the principal target is defined by partly-coincident magnetic and gravity geophysical anomalies spanning a surface area measuring about 3500m by 5000m and reporting a 1500 nanoTesla (nT) magnetic response and 10.1 milligal (mgal) gravity response. The nT response points to a possible target depth lying between 520m and 700m below surface, which is likely to be overlain by thick post-mineral cover sequences of WA’s vast Canning Basin.
Buxton says the dipolar geophysical anomalism – where a high value response is paired with a second weaker response – conforms with an extent, amplitude and offset pattern with similarities to other world-class IOCG deposits such as BHP’s massive Olympic Dam operation in South Australia. Similar geophysical surveys at Olympic Dam reported 1000 nT from magnetics and 17 mgal gravity responses.
Buxton Resources chief executive officer Marty Moloney said: “Buxton has a very successful record in exploration and discovery and we’re super excited about getting a rig turning at Centurion because it has all the right ingredients for a sizeable alteration system. It was a privilege to work with the Parna Ngururrpa and Parna Kyanta people, who are the traditional owners of the area. We look forward to building on the strong foundation of partnership, trust and mutual respect that was established during this survey and we hope to share with them and our shareholders the thrill of a greenfields copper-gold discovery.”
The Centurion project lies within a promising regional complexity of structures centred around the intersection of two giant crustal-scale lineaments – the Lasseter shear zone and the Kimberley south-west shear zone. Remarkably, it also finds itself on the suture between the Kidson Craton and the Aileron geological province.
If ever there was a favourable plumbing system for mineralising fluids, this should be it.
Leading global mining group Rio Tinto – in its previous guise as CRA – put a single deep hole into the same target at Centurion in 1991 but the hole fell short of its basement objective and was abandoned at 432.3m depth. Despite the set-back, its geological logs recorded chlorite-pyrite-altered, boulder-sized clasts of felsic and mafic intrusives in a conglomerate assigned to the Permian Grant Formation near the end of the hole.
It has been viewed by Buxton as an encouraging sign that that the geophysical responses could be related to a hydrothermal system consistent with an IOCG model and that the basement interface may not be far below the base of that hole. The company now plans to drill about 1km south-west of the old CRA hole.
Management envisages a single, 1000m-deep vertical “parent” hole drilled close to the intersection of the magnetic and gravity anomalies, followed by two 650m-deep “daughter” holes wedged off the parent hole to laterally intercept each of the geophysical anomalies.
It is a strategy designed to pierce the geophysical targets at an optimal angle and also economises on time and meterage. At 432m deep, the old CRA hole fell just short of the top of the magnetic envelope, as it is currently modelled.
Buxton was awarded a WA Government exploration incentive scheme (EIS) grant to offset up to $220,000 of the cost of drilling its planned maiden drill hole at the project.
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By Doug Bright
