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Tennant Minerals hammers NT copper-gold with one-two drill combo

Tennant Minerals has started drilling at its Barkly project in the Top End to test for extensions to its high-grade Bluebird discovery.

Tennant Minerals (ASX: TMS) is charging into a major two-stage drill program to test for further extensions to high-grade copper-gold intersected at the company’s Bluebird discovery that sits within its flagship Barkly project in Australia’s Top End.

The phase one campaign will comprise 4500m of reverse-circulation (RC) drilling to test the Bluebird prospect, which remains open in all directions and has recently produced an impressive array of drill hits. One recent slice of 30.5m at 6.2 per cent copper and 6.8 grams per tonne gold got management’s heart-racing and included 17.8m going 5.2 per cent copper and 11.5g/t gold and 16.1m at 10.5 per cent copper with 0.44g/t gold.

Tennant says its phase two program will use a combination of RC and diamond drilling and is scheduled to punch 7500m into multiple Bluebird lookalike prospects, in addition to testing the company’s promising Perseverance target that was recently awarded a Northern Territory Government “Resourcing the Territory” co-funded grant.

The grant will cover up to 50 per cent of the diamond drilling costs.

Perseverance sits 2km west of Bluebird and the deep diamond drillhole will test a sizeable high-intensity coincident gravity and magnetic anomaly down-plunge to the west of the historical Perseverance gold mine. Previous assays from the mine returned high-grade gold, including 3m at 50g/t from 42m and 3m going 43.2g/t from 72m.

The company’s Bluebird-Perseverance corridor is a 2.5km highly-prospective patch of ground that may contain “repeats” of the high-grade mineralisation found at Bluebird. Only 500m has been tested to date.

Management notes that the objective of the drill program is to grow its Bluebird discovery and identify similar high-grade material, with the intention of defining a maiden mineral resource that can support a stand-alone development project. Further metallurgical testwork is planned after the completion of the drilling campaign.

‘This drilling is occurring at a time of globally rising demand for copper and strong pricing for gold.’
Tennant Minerals CEO Vince Algar

The company’s flagship asset is its 100 per cent-owned Barkly project, about 40km east of Tennant Creek. It is based on the eastern edge of the Tennant Creek Mineral Field (TCMF), a region that produced 5.5 million ounces of gold and 700,000 tonnes of copper between 1934 and 2005.

The area has unveiled high-grade copper-gold deposits such as the Warrego mine, with 6.75 million tonnes at 6.6g/t gold and 1.9 per cent copper, in addition to the Peko mine that produced 3.7 million tonnes going 4 per cent copper and 3.5g/t gold.

Tennant made its Bluebird copper-gold greenfields discovery under shallow cover and within weathered Warramunga Formation sediment rocks, hosted in mineralised ironstone with a 5km geophysical footprint. Drilling at the deposit has identified copper-gold for more than 800m of strike length and at depths greater than 400m.

Management says the mineralisation is associated with intense hematite alteration and brecciation with malachite, natural copper and visible gold in the upper parts of the zone. It then transitions to primary sulphide mineralisation, including chalcocite-bornite-chalcopyrite.

Several eyebrow-raising intersections have been recorded from Bluebird’s western zone, with 61.8m at 2.3 per cent copper and 0.4g/t gold from 149.2m including 13.2m going 9.6 per cent copper and 1.51g/t gold from 149.9m that also included a tasty 6.85m slice at 17 per cent copper with 0.5g/t gold. And in keeping with the stellar numbers thrown up from drilling, the company also encountered 17.95m at 2.7 per cent copper and 11.1g/t gold including a bonanza slice of 5m at 6.1 per cent copper and 38.6g/t gold.

The company says that while Bluebird is its “main game”, it is not overlooking the potential of its Perseverance target. Historical drilling and modelling of geophysical data has identified a major ironstone-hosted copper-gold target associated with workings from the old mine and sitting below previous drilling.

An eastern view of Tennant Minerals’ Barkly project in the NT.

A west/south-west-trending gravity high has been modelled, linking the high-grade Bluebird deposit with gravity features identified below the old gold workings at Perseverance. Management believes the mineralised system in its ground may represent the upper parts of a major deep-seated copper-gold corridor.

Interestingly, there is a history of gravity highs that indicate widespread iron-enrichment being associated with some of the major deposits discovered within the TCMF.

The company recently revealed that it has also identified shallow mineralised ironstone at its Bluebird East target, sitting 500m east of its Bluebird find. Management says a structural interpretation suggests a possible link between the main Bluebird zone and its Bluebird East prospect.

Results from drilling at the target produced further stunning intersections of 14.1m at 10.4 per cent copper equivalent, comprising 7.6 per cent copper, 2.4g/t gold and 0.32 per cent bismuth from 90.64m. A super high-grade 2.6m hit 31.5 per cent copper equivalent consisting of 18.8 per cent copper, 12.3g/t gold and 1.08 per cent bismuth from 97.38m.

Tennant wasted little time in completing metallurgical testwork on the mineralisation, with results indicating that a 10-times uplift to assay grades for copper and an 8-times increase in gold grades was possible when concentrating the ore to produce material suitable for sale. High concentrate grades exceeding commercial benchmarks were achieved, with copper mineral chalcopyrite of 2.7 per cent and 0.47g/t gold able to be upgraded to 29.6 per cent copper and 3.96g/t gold.

Flotation recoveries for that batch of sampled material returned 94.4 per cent copper with 75.8 per cent gold, while a high-grade sample of 9.7 per cent copper and 1.55g/t gold yielded concentrate levels of 26.5 per cent copper and 2.36g/t gold. Significantly the copper recovery was an impressive 98 per cent, with gold coming in at 57 per cent.

Management says it is conducting ongoing metallurgical analysis to extract the unrecovered gold that is finding its way into flotation tails. It is using gravity and leaching, in addition to further work on developing part of the process circuit to improve recovery levels.

The Barkly project sits about 20km east of the new Nobles Nob processing plant being erected in the TCMF and may provide an opportunity to unlock the treatment of its ore. An issue in the TCMF has been that of “stranded” assets, where no facilities have been available within a reasonable distance to process the ore from many of the region’s junior explorers that have made significant discoveries.

Both copper and gold prices have surged at times this year and although they may have retreated a little, they still sit comfortably above last year’s levels.

So, Tennant may just have chosen the right commodities to chase due to the expected future copper resources needed to help with the electrification of global energy needs and with central banks around the world hoarding gold as a safe haven in uncertain economic times.

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