Middle Island Resources has prioritised exploration targets for iron oxide-copper-gold mineralisation and sediment-hosted base metals of copper-zinc-lead-silver at its Barkly project near Tennant Creek in the Northern Territory.
The company says one of its company’s application areas has two high-priority shallow targets based on historic data that reveal a pathway copper-gold indicator of silver showing 87 grams per tonne.
Management has ranked 55 targets identified for IOGC mineralisation and sediment-hosted base metals based on the character, amplitude and size of the target signatures (gravity, magnetic and structural) and their depth. Its focus is on the priority shallow targets as most of them have no surface expression due to sedimentary cover of some 100m to 400m.
The objective is to utilise prospect-scale soil sampling and ground gravity geophysics methods to high-grade targets, leading ultimately for them to be tested by the drillbit.
Silver is seen as a pathway copper-gold indicator as many high-grade copper-gold deposits in the Tennant Creek region contain significant amounts of the lustrous metal.
Middle Island has an application pending in which two high-priority, shallow prospects – Eiger and Zermatt – occur. Historic vacuum drilling revealed silver anomalies showing from the top of bedrock samples up to 87g/t.
The exploration team has shown the prospects to be on structures coincident with a gravity magnetic-defined ridge in prospective mineralised stratigraphy. The plan is now to further constrain the areal extent of the prospects from a 400m-by-200m historic vacuum-drilling grid to a tighter soil-sampling grid, as typical Tennant Creek copper-gold deposits have small footprints of the order of 200m-by-50m.
Middle Island Resources chief executive officer Roland Bartsch said: “On joining MDI in April, one objective was to reassess the many Barkly Project exploration opportunities. The advancement to prospect scale work on the assembled portfolio of priority targets, that includes shallow opportunities, is an exciting next step toward drill plans on a spread of drill targets. The systematic approach adopted is integral to MDI’s exploration strategy to add value through growth of scientific understanding and concepts, enabling resources and future drilling to be focused on the top targets, maximising the potential for exploration drilling success.”
Middle Island plunged four diamond drillholes for a total of 3025m into its Crosswinds copper-gold prospect last year, searching for the source of outcropping malachite mineralisation and the induced-polarisation (IP) anomaly. All holes showed IOGC-style alteration affinity and assay results are pending.
Australia has two major IOCG provinces of global significance – the Olympic Dam IOCG province along the eastern margin of the Gawler Craton in South Australia and the Cloncurry district in the eastern Mount Isa Inlier of north-west Queensland.
So, could there be more bite to the bark in a what is clearly a highly- mineralised area? Middle Island will be hoping its future drilling can prove it.
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By Gary Kjellgren
