• The Mesa B, C, and H deposits are Channel Iron Deposits (CID).
• The deposits are a part of a series of flat topped hills, defining the paleochannel of the Robe River. They consist of pisolite infilling the paleochannel, which cuts across the Cretaceous to Proterozoic stratigraphy.
• Mineralisation is confined to the Tertiary Pisolite.
• A hydrated hardcap overlies the mineralised pisolite.
• Non-mineralised clay layers and pods have been domained separately.

All mines operated by Rio Tinto within the Robe Valley property are open pit mines. The mining method employed uses conventional surface mining, whereby shovels and loaders are used to load drilled and blasted material into trucks for removal to waste dumps or feed to process plants.

First ore at Robe Valley (Mesa B, C, H) was achieved in August 2021.

At Robe Valley (Mesa B, C, H), the autonomous mining truck fleet has been commissioned.

Ore from the Robe Valley mines of Mesa A and Mesa J is processed through either dry crushing and screening plants or through wet processing plants using scrubbing and screening to remove finer particles. Crushed and deslimed ore from the Robe Valley mines is railed to Cape Lambert, where further dry crushing and screening through a dedicated processing plant produces lump and fines iron ore products.

The product will be railed to Cape Lambert to generate a lump and fines product. Conversion of railed products to shipped products is based on the results of test work that estimates the conversion during rail and port handling process.