Extraction

Lithium is cheifly extracted from two types of mineral deposit:

• Hard-rock deposits (i.e. pegmatites)

• Brines (i.e. continental brines)

Hard-rock deposits are typically mined using similar techniques to many other metals, using surface (open-pit) or sub-surface (underground) methods. However, brines are liquids and are therefore extracted by pumping from wells. Hard-rock lithium deposits that are near surface (usually at a depth of less than 100 metres) are mined using open-pit mining methods, which generally invovles removing overburden (i.e. unmineralised soil and rock), digging the ore or blasting with explosives, then removing the ore by truck or conveyor belt for stockpiling prior to further processing.  Underground mining methods are used when surface mining methods become too expensive, for example when a deposit is buried too deeply. Initially, an adit (horizontal), shaft (vertical) or decline (at an angle) will be sunk to access the buried deposit, the ore is then mined using explosives and specialist mining equipment. The ore is tranposrted to surface for processing using trucks, conveyor belts or underground rail systems. 

During the past decade global production of lithium has been fairly evenly split between extraction from hard-rock deposits (c. 37-65%) and extraction from continetal brines (c. 35-63%); however, since 2016 production from hard-rock sources has dominated.  During this time production of lithium has increased significantly from almost 28,000 tonnes in 2011 to more than 115,000 tonnes 2021 (Figure 1). Australia and Chile have been the dominant producers during this period, with these two countries accounting for more than 70% of the global total each year. Mine production from China, Argentina and the RoW has also generally increased during this time, although at a slower rate compared to Chile and Australia.