Lithium developer, AVZ Minerals, has now concluded Phase 1 sighter test work using a 250mm cyclone-fitted, industrial size, dense media separation pilot plant at its amazing Manono lithium-tin project in the Democratic Republic of the Congo.
The Perth based ASX-listed company says the results are encouraging with excellent lithium, tin and tantalum recovery rates at the 400 million tonne project that boasts and almost off the scale global resource grade of 1.65% lithium oxide.
Importantly, results from the coarser 250mm crush size mirror those at the finer 100mm crush size, with only minor adjustments likely to be required to bring them into line, management said.
The implication therefore is that coarser crush sizes should be suitable for liberating the sought-after mineral products via dense media separation, or “DMS”, techniques at Manono and it will likely benefit from lower operating costs as a result.
Additionally, both tin and tantalum recoveries from the DMS program and heavy media separation by gravity techniques proved promising and will be further explored in the ongoing confirmatory Phase 2 test work, AVZ said.
Tin and tantalum are very common by-products in the type of LCT-style lithium pegmatites the company is developing at Manono and those metals often accompany the primary lithium spodumene minerals during the formation of the pegmatite ore systems.
Having said that, very little lithium is actually tied up with the tin and tantalum mineralisation and therefore, losses of lithium during DMS and heavy media separation tend to be minimal.
Only 0.03% lithia loss has been measured from the Manono met work to date, providing some indication that the tin and tantalum could end up providing valuable economic credits for the giant project.
Importantly, analyses of DMS concentrates recently showed that iron and mica mineral concentrations are within chemical-grade lithium concentrate specifications, but outside the higher-value ceramic grade limits.
The company said it would continue investigations into the source of the iron, which may provide some direction as to whether or not a further reduction in the contaminant may be possible.
The Phase 2 test work programs are aimed at optimising ore concentrate grades and recoveries the company said.
AVZ also indicated that it was on the cusp of appointing a new Non-Executive Chairman, who it said had an excellent track record of complementary and relevant experience in the mining industry and in particular, in the DRC.
Managing Director Nigel Ferguson said: “The results of our Phase 1 metallurgical program will now allow GR Engineering Services to rapidly advance the Definitive Feasibility Study, which we expect will be completed around Q1 2020.”
“Further optimisation of our DMS250 metallurgical test work will aim to improve our concentrate grade and recovery rates. Tin and tantalum recovery from the DMS250 are very encouraging and it is expected that further test work will improve on these numbers.”
AVZ controls a 65% interest in the world-class Manono project in the DRC, which contains the impressive Roche Dure mineral resource, which is one of the single largest accumulations of high-grade, spodumene-dominated, pegmatite-hosted ore systems defined in the world today.
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By Matt Birney
