Ann: Sinclair Mine Complete, First Caesium Shipment Scheduled, page-164

The feldspar is likely to remain as overburden. At $50 a tonne to transport to Esperance and $40 a tonne to crush and ship to SE Asia with an at best price of $100 a tonne the profit margin is unlikely to be worth the risk.

The petalite (ceramic market) and lepidolite (Chinese lithium) do have value and should hopefully result in offtake agreements. If offtake partners want what is left as stage 2 mining then it should be profitable to remove and stockpile the feldspar assuming it has no value and extract the petalite and lepidolite.