The Greenbushes deposit consists of a main, rare-metal zoned pegmatite body, with numerous smaller footwall pegmatite dykes and pods. The primary intrusion and its subsidiary dykes and pods are concentrated within shear zones on the boundaries of granofels, ultramafic schists and amphibolites. The pegmatites are crosscut by ferrous-rich, mafic dolerite which is of paramount importance to the currant mining methods. The pegmatite body is over 3 km long (north by northwest), up to 300 meters wide (normal to dip), strikes north to northwest and dips moderately to steeply west to southwest.

The major minerals from the Greenbushes pegmatite are quartz, spodumene, albite and K-feldspar. The main lithium-bearing minerals are spodumene (containing approximately 8% lithium oxide) and varieties kunzite and hiddenite. Minor to trace lithium minerals include lepidolite mica, amblygonite and lithiophilite. Lithium is readily leached in the weathering environment and thus is virtually non-existent in weathered pegmatite. Exploration drilling at Greenbushes has been ongoing for over 40 years, including drilling in 2020, using reverse circulation and diamond drill holes.

Lithium ore (spodumene) at Greenbushes is mined from the fresh, unweathered zones in the pegmatite that are exposed in the open pits.

Mining is traditional drill and blast method with ore graded and stockpiled according to its mineralogical characteristics and grade. Waste material is trucked to designated areas within the site where it is contoured and replanted as part of an ongoing rehabilitation plan.

The Greenbushes mining operations has three processing plants, one producing technical grade lithium concentrates and two producing chemical grade lithium concentrate. Ore containing Li2O is fed into the processing plants which upgrade the lithium mineral, using gravity, heavy media, flotation and magnetic processes, into a range of lithium concentrates for bulk and bagged shipments.

Two of these plants, Chemical Grade Plant (CGP)1 and CGP2, produce chemical grade lithium concentrates (6.0% Li2O) with a combined installed production capacity of 1.2Mtpa. The single Technical Grade Plant (TGP) produces low-iron technical grade concentrates (5.0 – 7.2% Li2O) at a production rate of 150ktpa for the ceramics, glass and metallurgical markets. Greenbushes is one of only two operations globally which have the ore quality to produce technical grade concentrates.

Greenbushes lithium mine has an annual production capacity of 1.2Mtpa of chemical-grade spodumene concentrate ........