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Argonaut Resources carves out Zambian exploration upside with visible copper mineralisation in Nyungu core

Last updated: 12:54 18 Nov 2021 AEDT, First published: 12:05 18 Nov 2021 AEDT

Argonaut Resources NL - Argonaut Resources carves out exploration upside at Nyungu Copper-Cobalt with visible copper mineralisation

Argonaut Resources NL (ASX:ARE)’s geologists have confirmed observation of visible copper mineralisation in drill core from the Nyungu Central and East copper-cobalt deposits at Lumwana West Project in Zambia, offering an opportunity to potentially increase the Nyungu mineral resource.

Drilling began in July, the program constituting 2,800 metres of intended diamond drilling at Nyungu Central and South deposits, and 1,500 metres reverse circulation (RC) drilling at the Nyungu East copper anomaly.

Nine of ao diamond drill cores contained notable intercepts of visible copper, with hole NYDD053 hitting significant visual mineralisation in the form of apparent chalcocite and native copper at 117.6 metres. An 11th drill hole is in progress, bringing current meterage to 2,486 of 2,800 metres.

Three zones of copper mineralisation

Drill core observations have categorised mineralisation at Nyungu Central in three zones: the oxide zone, transitional zone and primary zone.

Oxide copper mineralisation tends to be lower grade but is also processed at a lower cost and occurs more abundantly, while primary copper mineralisation in sulphide forms tend to hold much higher concentrations of copper and are more easily separated from unwanted minerals.

Drill hole NYDD062 was expected to drill through mineralisation by 250 metres of depth but has continued to return visual mineralisation at 300 metres and beyond, with the hole currently sitting at 308 metres.

Samples are being progressively submitted and prepped in Zambia then air freighted to Australia for analysis.

The Nyungu Central deposit is open along strike to the north and south. Argonaut is testing these potential extensions to known mineralisation with a view to increasing tonnages for future resource estimation and converting exploration targets into a JORC certified resource.

Nyungu East RC drilling

A soil sampling program undertaken by Argonaut defined an intense copper anomaly at Nyungu East, with peak copper in recently acquired soil samples at 2,100 parts per million (ppm), 8-10 times higher than peak values at the neighbouring Nyungu Central copper-cobalt deposit.

The RC program at Nyungu East has so far consisted of six holes averaging 92 metres of depth, with drilling ongoing.

Metallurgic test-work

Argonaut has been testing the metallurgical properties of oxide, transitional zone and fresh (sulphide) ores for the past 18 months, using the data to drive the development of process flowsheets and scoping economic studies into the various processing options.

The company has completed testing of mineralogy, comminution, flotation and oxidation (including both roast/leach and Albion process).

A suite of orientation leach tests on small samples of oxide and transitional ores is being completed. Future tests will include large-scale leach tests, bio-leach tests and solvent extraction/electrowinning (SX/EW) tests.

Mining study

A preliminary open pit optimisation study was conducted for the Nyungu Central and Nyungu South deposits. The modelling was for copper production only, using costs from similar mines. Argonaut says the results were highly encouraging.

Modelling shows excellent deposit geometry via a very low stripping ratio:

  • Stripping ratio of 1.5 to 1 for the optimum pit at a copper price of US$7,151; and
  • Stripping ratio of 2.3 to 1 for depths greater than 300 metres at 150% of the current copper price, indicating the deposit has a low sensitivity to stripping ratio.

Why Zambia for cobalt?

Recent battery-related demand for cobalt has exposed the fragile nature of cobalt supply. Over 70% of the world’s cobalt is coming from the Democratic Republic of Congo (DRC), one of the world’s riskiest and most opaquely administered mining jurisdictions.

Of the 190 countries assessed for ‘ease of doing business’ by the World Bank in 2019, Zambia ranked 85. DRC ranked near the bottom at 183. According to Argonaut, Zambia is a far safer and lower-risk jurisdiction that benefits from politically stability, robust mining law and functioning courts.

For the company, Zambia represents a blend of lower political risk, excellent mineral endowment, and favourable metallurgy.

About Argonaut

Argonaut Resources is an Australian Securities Exchange-listed exploration and development company focused on the Murdie Copper Project in South Australia and copper development at the Nyungu copper-cobalt deposit at Lumwana West project in north-western Zambia.

Argonaut has plans to list its uranium subsidiary, Orpheus Minerals Ltd, on the ASX.

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