Exploration

Exploration for lithium has rapdidly expanded as a result of both rising demand and the predicted increase in future demand, with some forecasts suggesting metal requirments in 2050 will be around 2100% higher than overall use in 2020 (KU Leuven, 2022). There are currently more than 300 lithium exploration projects at varying stages of development (i.e. exploration, pre-feasibility, feasibility and construction). The majority of these projects are located in Australia, Canada, Argentina and the United States of America. However, it is likely that many of the projects will not receive the investment required to become operating mines. 

Lithium-bearing mineral resources are known across the globe, occurring in a range of deposit types in a variety of geological settings (Figure 1). However, lithium is principally extracted from two types of mineral deposit: hard-rock deposits and brines. In terms of hard-rock deposits lithium is cheifly extracted from lithium aluminosilicate minerals, such as spodumene and petalite that are found in pegmatites. Other lithium-bearing minerals, for example hectorite, a lithium-rich clay and jadarite, a lithium-borosilicate are not currently exploited on a commercial-scale but may become important sources of lithium in the future. There is also increasing interest in recovering lithium from lepidolite and zinnwaldite, lithium-bearing micas that are typically found in hard-rock (pegmatite) deposits. Lithium extraction from brines is principally from continental brine deposits, such as the salt lakes and salt pans of the central Andes in South America. The extraction of lithium from geothermal and oilfield brines, although technically feasible, is not currently taking place but may become important in the future (Brown, 2016). See table below for an overview of the charateristics of hard-rock and brine-hosted lithium deposits.

Resources and reserves of lithium

Data held by the United States Geological Survey (USGS) indicate there are significant global resources and reserves of lithium. Global resources of lithium are currently estimated to be about 183 million tonnes, whilst reserves are estimated to be about 26 million tonnes. Although, distributed across the globe a significant proportion (>80%) of lithium resources are found in only five countries, namely the United States, Argentina, Bolivia, Australia and Chile. A similar concentration is seen in the distribution of lithium reserves, with only four countries accounitng for >70% of global reserves, including Australia, the United States, Chile and Argentina (Figure 2). The majority of lithium resources and reserves in Chile, Argentina and Bolivia are associated with continental brines, whilst in the United States and Australia hard-rock hosted lithium resources and reserves dominate. 

Figure 2: Global distribution of lithium resources and reserves expressed as tonnes of lithium. Left hand diagram shows global distribution of lithium resources, with RoW (rest of world) comprising countries with resources of less than 3 Mt, including Kazakhstan, Austria, Finland, Ghana, Namibia, Portugal, Spain, Zimbabwe, Brazil, Mali, Peru, Russia, Serbia, Czech Republic, Mexico and Canada. Right hand diagram shows the distribution of global lithium reserves, where RoW (rest of world) comprises countries with reserves of less than 1 Mt, including Portugal, Brazil, Zimbabwe and Canada. Data source: USGS (2023).