Rainbow Rare Earths Ltd (LSE:RBW, OTC:RBWRF) has upgraded the resource at Phalaborwa by 15% adding two years to the project life.
Total measured, indicated and inferred resources now stand at 35 million tonnes at 0.44% TREO [rare earths], with a near doubling in the material now classified as measured.
Light rare earth elements neodymium (Nd) and praseodymium ("Pd") represent 29% and the heavy REEs dysprosium (Dy) and terbium (Tb) represent 1% and 0.3% respectively.
Rainbow added the resource also included even rarer elements in the SEG group (samarium, europium and gadolinium), lanthanum (La) and cerium (Ce).
Based on current spot prices for a TREO basket, Rainbow said the resource has an in-situ metal oxide value of US$3.7 billion.
A 0.2% TREO cut-off grade was used for the estimates with, at expected production rates, the project life now 16 years against 14 years previously.
George Bennett, Rainbow, chief executive, said the new resources underline the huge intrinsic value of the project.
“It also points to the potential for value from other recoverable REEs, which are currently not included in our project economics, and the MRE has an in-situ metal oxide value of ca. US$3.7 billion even at today's lower spot prices.
“It's worth noting that this is a very different type of Resource to that of a hard rock mining project, sitting at the surface with a relatively homogenous distribution in the phosphogypsum stacks.
“Therefore, we intend to process the entirety of the stacks, allowing us to generate value from the full 35 Mt Resource."
Bennett added that the four most economically important REEs, Nd, Pr, Dy and Tb, together represent over 30% of the basket by volume at Phalaborwa and 96% by value.
He noted these have been designated globally as critical minerals for the green energy transition due to their use in the permanent magnets essential for electric vehicles and wind turbines.