FYI - Types of Lithium DepositsExcerpts from an article in investingnews.com: Lithium Deposits: Brine, Pegmatite, or Sedimentary (Clay or Lacustrine)
Melissa Pistilli
Oct. 14, 2021
Lithium brine deposits have been generating interest, but what about pegmatite lithium deposits and sedimentary lithium deposits?
As lithium demand continues to rise, it is useful for investors to gain an understanding of the different lithium deposit types at play.
Lithium is mined from three different deposit types: lithium brine deposits, pegmatite lithium deposits and sedimentary lithium deposits. Each comes with different project requirements, extraction methods and processing times.
Brine deposits, for example, are the most common, accounting for more than half of the world’s lithium resources, but may require longer processing periods. The majority of global lithium production comes from continental lithium brine deposits.
Pegmatite is a coarse-grained intrusive igneous rock formed from crystallized magma below the Earth’s crust. Pegmatite lithium deposits, also known as hard-rock lithium deposits, can contain extractable amounts of a number of elements, including lithium, tin, tantalum and niobium.
Lithium in pegmatites is most commonly found in the mineral spodumene, but also may be present in other minerals such as petalite, lepidolite, amblygonite and eucryptite.
Hard-rock ore containing lithium is extracted at open-pit or underground mines using conventional mining techniques. The ore is then processed and concentrated using a variety of methods prior to direct use or further processing into lithium compounds.
Extracting pegmatite lithium from hard-rock ore is expensive, meaning that such deposits are arguably at a disadvantage compared to brine deposits. However, pegmatite lithium deposits have considerably higher lithium concentrations than brines, so deposits with extremely high lithium values may still be economically viable. The production of other metals, such as tin and tantalum, can also help offset costs. It is worth noting that hard-rock deposits are not subject to the sometimes 12 month long processing times currently seen at some brine deposits.
Sedimentary rock deposits account for about 8 percent of known global lithium resources, and are found in clay deposits and lacustrine evaporites.
In clay deposits, lithium is found in the mineral smectite. The most common type of smectite is hectorite, which is rich in both magnesium and lithium. It gets its name from a deposit containing 0.7 percent lithium found in Hector, California.
Many companies are in the research and development phases for their clay deposits, but no companies currently produce lithium from them.
The most commonly known form of lithium-containing lacustrine deposit is found in the Jadar Valley in Serbia, for which the lithium- and boron-bearing mineral jadarite is named.
The Jadar deposit, owned by Rio Tinto (NYSE:RIO,LSE:RIO,ASX:RIO), reportedly contains more than 200 million tonnes of lithium. The company claims it is one of the largest lithium deposits worldwide.
Rio Tinto signed a memorandum of understanding with the government of Serbia to fast track the development of the deposit. The project is currently in the prefeasibility stage and could begin construction in 2022. Rio Tinto has committed to US$2.4 billion to developing the project.