Special Report: Preliminary metallurgical test work indicates that gold could be produced from Magnetic’s Hawks Nest 9 (HN9) deposit in WA at a comparatively low cost.

The test work returned very encouraging gravity and leach recoveries averaging 88.5 per cent in the oxide zone, 91.2 per cent in the transition zone and 93.4 per cent in the fresh zone.

Notably, the testing required low consumption of cyanide and lime reagents, which could reduce processing costs for Magnetic Resources (ASX:MAU).

As a further benefit, the results show low levels of deleterious elements that could impact on gold recoveries.

“These preliminary metallurgical results are most encouraging, showing potential for good gold combined recoveries with low reagent consumption,” managing director George Sakalidis said.

“The high gravity recoveries of up to 65% and the difference between the calculated composite sample grade and the assay grade suggest the presence of coarse gold which could be expected to report to the gravity circuit and thus reduce overall costs.

“Further test work is being planned to examine this aspect.”


Gold test work

Magnetic had carried out the test work on 10 composite samples, two from the limited oxide zone and four each from the more extensive transition and fresh rock from across the known 3km long extent of HN9 mineralisation.

These samples were subject to crushing and grinding; Knelson concentration of each sample; intensive leach test analysis of the Knelson concentrates; and bottle roll cyanide leach test analysis of the combined Knelson tail and intensive leach residues.

Gravity recovery ranged from 23 per cent to 65 per cent while bottle roll tests returned gold recovery ranging from 65 per cent to 94.9 per cent.

Additionally, kinetic leach curves show that most of the leaching is complete after 24 hours.


High-grade gold

Magnetic recently identified at least four stacked thickened porphyry zones within HN9 after drilling returned thick intersections such as 104m at 0.82 grams per tonne (g/t) gold from 8m including 20m at 2.23g/t gold and 70m at 0.49g/t gold from 13m.

A number of new high-grade results such as 1m at 85.6g/t gold from 45m and 1m at 11.1g/t have also been intersected in the southern and northern parts of the thickened zone respectively.

HN9 is interpreted to look like the neighbouring 7Moz Wallaby and 10Moz Jupiter deposits, which have internal shallow-dipping mineralised lodes that have been defined – in Wallaby’s case – down to a depth of about 1.5km.


This article was developed in collaboration with Magnetic Resources, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions