Metallurgical test work has been undertaken on primary sulphide, oxide and transition mineralisation, with sighter flotation test work on sulphides showing similarities to Southern African sulphide PGM ores.
Oxide mineralisation from Parks Reef processed through flotation would provide Podium an opportunity to generate revenue from near-surface material.
The company is also investigating alternative process routes to maximise payable PGM, gold and base metal recoveries.
Sulphide samples similar to Southern African ore types
The drill samples collected from Parks Reef were tested in South Africa by Mintek with supervision from DRA Pacific Pty Ltd.
Initial results from a sulphide sample have shown some similarities to Platreef and Great Dyke ore types, from South Africa and Zimbabwe respectively, with similar base metal contents.
A sighter test using standard flotation conditions returned a rougher circuit PGM recovery of 71% and copper recovery of 69%.
A single open circuit cleaner test on the rougher concentrate achieved a grade of 58 g/t PGM and 5% copper with cleaner stage recoveries of 73% and 85%, respectively.
The rougher test is considered indicative of overall recovery potential while the open circuit cleaner test is indicative of potential concentrate grades.
A follow-up test with the addition of a secondary rougher stage with a finer grind was shown to increase rougher circuit PGM recovery to 81%.
Testing of a shallow oxide sample under different float conditions achieved rougher circuit PGM recoveries between 44-48% which is similar to recoveries on Southern African oxide ores.
Flotation recoveries in the oxide zone are likely to be variable with a second shallow sample shown to have minimal free-floating PGMs.
Podium expects performance will improve with depth, as analysis of a deeper transitional sample showed bulk mineralogy more similar to the fresh sulphide sample.
Alternative processes to maximise payable metals
Given Parks Reef’s unique characteristics as a shallow polymetallic bulk mining operation, Podium is exploring alternative processes to maximise payable metals from the oxidised mineralisation.
This investigation has a strong focus on gold and base metals.
The company has held initial discussions with specialists in PGM, gold and base metal leaching processes at the Western Australian School of Mines.
Podium envisages a low capital cost leaching operation that would optimise recoveries and produce high-purity products from the near-surface oxide material.
Resource modelling for platinum, palladium and gold, as well as significant base metals, is underway.
Metallurgical test results will suppose this modelling work and will provide a basis for engineering and project development studies.