The current Mineral Resource estimates for Rhyolite Ridge are detailed in the announcement titled “Updated Rhyolite Ridge Mineral Resource Statement” dated 23 October 2018.
At a 1,050ppm lithium cut-off, the Rhyolite Ridge Mineral Resource estimate totals:
- 475 million tonnes at 0.9% lithium carbonate and 2.3% boric acid
- Containing 4.1 million tonnes of lithium carbonate and 10.9 million tonnes of boric acid.
At a 1,050ppm lithium and 0.5% boron cut-off, the high-grade lithium-boron portion of the Mineral Resource totals:
- 121 million tonnes at 0.9% lithium carbonate and 7.1% boric acid
- Containing 1.1 million tonnes of lithium carbonate and 8.6 million tonnes of boric acid.
The high-grade lithium-boron mineralisation was the focus of the Rhyolite Ridge PFS as it represents the highest value material and simplest to process. This is due to the low-clay and high-searlesite content of the rock, which makes the lithium-boron ore amenable to low-cost acid leaching.
Located on only part of the western side of the South Basin, the Mineral Resource remains open to the north, south and east and has significant potential to expand with further drilling of the South Basin.
US Borax discovered significant amounts of lithium and boron in the North Basin during the 1980's. Two holes have been drilled by ioneer in the North Basin and further drilling will be necessary to estimate an initial Mineral Resource for this large area.