Emerging Democratic Republic of Congo producer AVZ Minerals (ASX: AVZ) has struck high-grade lithium after drilling beneath the floor of the historic Roche Dure pit at the Manono lithium and tin project.
A drill hole returned 203.3m at 1.59% lithium oxide and 1,014 parts per million tin.
The company says that pit floor mapping and drilling confirms slightly weathered to fresh pegmatitic rock makes up the pit floor and this will likely be fed into an updated resource which is expected in the current quarter.
Now clear lithium-tin lie below old pit floor
Managing director Nigel Ferguson says these drilling results, combined with the pit floor mapping, confirm that the wedge is in fact made up of pegmatitic rock that was historically mined as tin-bearing feedstock.
“This area had previously been categorised as waste material in our current mining and financial model due to lack of drilling data and under our current model is [to be] pre-stripped as waste before ore can be sent to the processing plant.
“These positive drill results unequivocally demonstrate this is not the case and this material may be remodelled with increased confidence as revenue generating ore once all the assay results are returned, “ Mr Ferguson added.
The historic Manono mine was exploited for its tin content between 1919 and 1982, during which time a total of 100 million cubic metres of ore was processed to produce 185,000t of cassiterite concentrate.
With the exception of some exploration work carried out on the old mine dumps, aimed at determining cassiterite and spodumene grades, little prospecting has taken place since 1960.
Tests confirm battery-grade lithium
Last month, AVZ reported that bench tests in Canada had confirmed that primary lithium sulphate (PLS) from the proposed Manono mine is suitable feedstock for lithium-ion battery production.
And an independently tested planned production flow sheet shows that Manono’s primary lithium sulphate with greater than 80% lithium content can be produced at the DRC project.
Kingston Process Metallurgy of Kingston, Ontario, conducted the bench-scale tests to produce 1.5kg of PLS from 9kg of spodumene concentrate shipped from the DR Congo.