Rainbow Rare Earths reports that the maiden Joint Ore Reserves Committee- (Jorc-) compliant mineral resource estimate for its Phalaborwa project has an inferred estimate of 38.3-million tonnes at 0.43% total rare earth oxides, which is larger than the 35-million tonnes initially expected from the gypsum stacks.
The maiden Jorc mineral resource has been estimated based on the assay results received from 1 056.3 m of auger drilling completed in December 2020.
The project contains neodymium and praseodymium oxide – the essential metals for permanent magnets that are being used in electrical components and represent 29.1% of the total contained rare earth oxides, with an in-situ value of $95/t of gypsum.
Rainbow also notes that the economic dysprosium and terbium oxide credits, with an in-situ value of $28/t of gypsum, enhance the overall value of the rare earth basket contained in the stacks, with the in-situ value of these four high-value rare earth elements totalling $123/t of gypsum.
Also, there are low levels of radioactive elements confirmed in the inferred mineral resource estimate, which Rainbow says confirm the “green credentials” of the project.
CEO George Bennett says the maiden mineral resource estimate for Phalaborwa marks an important milestone for Rainbow, underpinning the opportunity for the rapid development of a low-capital and low-operating cost, high-value processing facility in South Africa to provide the essential metals to power the “green revolution”.
He explains that because the rare earths are present in a chemical, rather than a mineral form in the gypsum stacks, it removes the need, as with the majority of global rare earth projects, to firstly produce a mineral concentrate before undertaking a complex and energy-intensive cracking process.
The initial Phalaborwa process will deliver a cracked rare earth carbonate and studies are ongoing to investigate whether the rare earth metals can be delivered as separated rare earth oxides for direct sale to industrial users.
“This gives us confidence that Phalaborwa will become the cornerstone of Rainbow’s business in the near term,” says Bennett.
Alongside the recently announced metallurgical test work results, which have confirmed that the gypsum stacks are amenable to simple, direct leaching with low-cost sulphuric acid at ambient temperature and pressure, he says the roadmap to commercialising the Phalaborwa deposit is now clear.
“We look forward to announcing further metallurgical test work results ahead of completing an initial scoping study/preliminary economic assessment in [the third quarter of this year],” says Bennett.
As such, further metallurgical test work is ongoing with Ansto Minerals in Australia to define a preliminary processing flow sheet to support a scoping study/preliminary economic assessment for the Phalaborwa project.