ASX-listed Carnaby Resources and its joint venture partner DiscovEx Resources have achieved excellent results during metallurgical test work from the JV’s Nil Desperandum prospect within its Greater Duchess copper-gold project at Mt Isa in Queensland. Copper recoveries of up to 99 per cent and high gold recoveries between 80 per cent and 87 per cent were achieved from the prospect.
The copper minerals were found to float quickly with more than 90 per cent of the copper having floated in the first two minutes of the testing. A second stage consisting of seven minutes of flotation brought the copper recovery up to about 99 per cent.
Flotation is a common and effective method used in an ore processing circuit. The ore is firstly ground into fine particles and then introduced into a liquid where air or gas bubbles are pumped through. The mineral-rich particles then attach to the bubbles and float to the surface at which point they are skimmed off the surface. In this case, the recovery rate describes the amount of copper returned from the process compared to the amount fed into the processing circuit.
Carnaby considers the preliminary results encouraging and says the initial test work has highlighted the potential for further improvements in concentrate improvements via an increase in pH and the use of a selective copper sulphide collector.
The metallurgical test work represents only the first scoping level stage with more extensive studies in the pipeline. Whilst the recent tests were performed on ‘fresh rock’ only, future studies will also test oxide and transitional ore characteristics.
Carnaby Resources Managing Director, Rob Watkins said: “These initial metallurgical results from the Nil Desperandum and Lady Fanny discoveries is a key de-risking event. The exceptional copper recoveries and lack of any deleterious elements indicate the potential for a highly sought-after quality concentrate product. Ongoing metallurgical studies will be completed in conjunction with initiated scoping level studies to produce a Mineral Resource estimate targeting Q2 2023 for the Greater Duchess Project”
DiscovEx holds a 17.5 per cent free-carried interest in what were known as the ‘Southern Hub Tenements’ that now covers most of Carnaby’s Greater Duchess copper-gold project.
At the time of Carnaby’s acquisition, the Nil Desperandum prospect was one of a handful of promising targets within the Southern Hub Tenement package. The prospect boasted historical workings across a strike length of 1km and historical intercepts including 6m at 5.2 per cent copper and 0.84 grams per tonne gold from 21m and 19m at 2.3 per cent copper and 0.56 g/t gold from 112m.
In December last year Carnaby built upon the historical intercepts with an impressive 41m hit going 4.1 per cent copper from 247m including a higher-grade 9m interval going 10.3 per cent copper. The discovery and the news that followed from the brownfields project sent shares in the explorer from a base of $0.27 on December 6, 2021, to touch a high of $2.20 in two months.
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