While many people think of lithium only in the context of batteries, it is a critical mineral supporting development of diverse new technologies in the 21st century. Global supply chains of years past must be rapidly expanded to meet new demands. Traditionally, lithium has been produced from both hard-rock mines and from highly saline brines brought to the surface and concentrated through evaporation. New mines can be developed, but surface concentration of lithium brines is limited to specific areas and is coming under increased environmental scrutiny. To address the demand, exploration companies have identified brines in saline aquifers as huge potential new lithium resources, but there are challenges to finding, appraising and developing them. This article will shed light on some of the current challenges and highlight some of the new exploration areas for future development of these brines.
Lithium Properties and Markets
Lithium is the lightest of the alkali metals (which include sodium, potassium, and some heavier metals). It is for this reason as well as others that it is desirable for battery manufacturing. It’s also highly reactive, combining rapidly with oxygen in air, so it has to be stored in vacuum conditions, inert atmospheres, or inert liquids such as mineral oil. Lithium is estimated to be the 25th most abundant element on earth.
Lithium-ion batteries have become prevalent in the past few years – not only in electric vehicles, but in a huge range of applications in portable electronic devices ranging from electric drills to smart phones. Lithium battery demand for electrical grid backup is an expanding field as well. In 2021, 74% of the lithium produced globally went to battery manufacturing.
There are two main sources of lithium extracted and produced for the current markets – pegmatites and brines. Pegmatites from hard-rock mining have been the primary source of lithium for the ceramics and glass sector. On the brine side, lithium carbonate is the primary supply to the battery sector, while lithium hydroxide and lithium chloride supply most of the other lithium applications such as for lubricating greases and continuous casting applications.
According to the United Stated Geological Survey (2020), lithium global reserves were about 17 million tons, from a combination of brines and hard rock. The top three reserve countries were Chile, Argentina (salar brines) and Australia, mainly hard rock. This compares to worldwide resource estimates of 80 million tons. On the other hand, worldwide mine production in 2019 was estimated to be in excess of 77,000 tons, with the top three producing countries being Chile, Australia and China.
Global lithium production and demand grew 21% and 33%, respectively, between 2020 and 2021, and continue to accelerate. As such, the market prices have reflected this move with demand. For example, spot prices for lithium carbonate in China rose from $USD 7,000/ton in January 2021 to more than $USD 78,000/ton at the start of April 2022. Likewise, fixed contract prices in the United States rose from $8,000/ton in 2020 to $17,000/ton in 2021(USGS 2022). Prices have since leveled off (at the time of this publication) but it is this market activity and demand that is driving the exploration for additional lithium resources.
Our challenge as geoscientists revolves around understanding some key points about lithium exploration from the onset. These are, namely, detecting the presence of lithium, knowing where the highest concentrations can be found, as well as understanding the source and genesis of the mineral in a given area of interest.
This article discusses current case studies where exploring for lithium has been carried out in three different environments. The first study is in a depleted oil field in the southwest corner of Arkansas, in the United States. The second is proximal to historical and current lithium production in the state of Nevada. Finally, the third case study discusses building a pilot project in the Landau area of Germany that has geothermal energy production operations.
Exploration Case Studies
When exploring for traditional oil and gas resources the explorationists must consider the key elements that make up a petroleum system. For lithium exploration in and around an existing oil and gas field, there are mainly three key elements that must be satisfied. The first of the three elements is the economic concentration of the lithium. In existing oil and gas fields it may be easier to assess the concentration as a result of water and geochemical analyses completed in the past. These are quite common in North American oil and gas producing areas and may assist greatly in focusing the exploration effort to a specific local area of interest. The second element to consider is the migration path. The path of the brine needs to be a porous and permeable conduit that allows the lithium to move into the rock, and preferably over large distances, to ensure adequate brine production potential. The third element to consider is the reservoir. It needs to be suitable to support economic flow rates to a wellbore for brine production and subsequent disposal. Trap is a less important factor because the operator will want as much water/ brine as possible to flow. In the case of an existing oil and gas field the seal has been proven effective so there is less need for a focus on this.
Southwest Arkansas Case Study
A recent example of lithium exploration is in a depleted oil field is in Arkansas. When oil was first discovered in South Arkansas in the 1920s, the brine was considered a worthless by-product of drilling and pumping. Industry later realized, in the 1950s, that the Late Jurassic Smackover Formation contained not only hydrocarbons but elevated concentrations of other elements such as bromine, that were economically viable on their own. Bromine extracted here has continued to be a sigificant source of supply to the global market to date. By reviewing and incorporating data from the USGS National Produced Waters Geochemical Database, which contains geochemical information from wellheads across the U.S., it was noted by explorers that this part of Arkansas had the highest recorded lithium brine (1,700 mg/L Li) concentration in the database. This naturally led to a concerted effort to produce lithium from this area by the operator, Standard Lithium Ltd., and the building of the Lanxess demonstration plant.
The lithium-concentrated brine is contained within the upper and middle members of the Smackover Formation. The formation is at a depth of approximately 2,700 m. The Smackover was deposited as part of a large carbonate platform that was formed as the supercontinent was being developed. Upper and middle Smackover members are defined by distinct stratigraphic horizons that consist of clean, porous, grainstones with lime-mudstone and fossiliferous lime-wackestone. Key to the prolific brine production in the area is the uniformity of this shelfal formation and its large areal extent. Brine volume and flow rates can be estimated from previous oil and gas exploration wells, as brine was a waste product at that time.
The upper Smackover formed the main oil and brine reservoir rock in the region due to its high porosity and permeability. It is about 60 m in average thickness. The average porosity and permeability measurements in a recent assessment west of the original production cites 10.2% and 53.3 millidarcies (mD), respectively, from 515 core plug samples. Lithium concentration estimates from the same study range from 132 mg/L to 461 mg/L (Standard Lithium Ltd., 2021). With this type of reservoir information, and abundant core data from existing wells, the exploration effort is off to a very good start to bring a project to fruition.
Clayton Valley, Nevada Case Study
Another approach to exploring and developing lithium is to return to areas that have already produced the commodity. The Clayton Valley in Nevada is one area that has seen a resurgence of activity in recent years because of this. Construction of production wells, a lithium carbonate production facility, and an evaporation pond system began in 1964 at Albemarle Corp.’s Silver Peak lithium location. Production commenced in 1967 and has continued essentially uninterrupted to present day.
The number and spacing of the wells used to extract this brine has generally not been published. Garret’s 2004 handbook on lithium and natural calcium chloride cites the Clayton Valley location with having 30 wells in 1969. Also, it is not clear whether flow rates cited are continuous or only for short times, but the handbook does give an idea of the scale of the opportunity compared to the Arkansas case study, where there were more than 2000 pre-existing wells drilled.
Lithium concentration and total production data for this facility is not well known, as proprietary production figures are not available publicly. Pumping tests and continuous production pumping records show that brine salinity in production wells range from 40,000 to 170,000 mg/L of total dissolved solids (TDS). Lithium concentrations exceeding 400 parts per million (ppm) have been extracted from the basin (Papke, 1976; Vine, 1980). Economic grades ranging between 230 ppm and 300 ppm have been reported (Kunasz, 1970; Davis et al.,1986).
As a result of this long-time production and nearby available data, considerable exploration work has been undertaken recently in an area to the south and west of the Silver Peak operation. One example is Nevada Sunrise’s work in the Neptune area. An elongated gravity low was first recognized by the USGS and drew the operator to investigate the area further. The survey, with data points taken approximately every 500 to 1000 m, highlighted a basin feature trending in a northwest-southeast direction and fault-bounded in a number of directions . The basin depth was calculated to exceed 1,300 meters in two locations, considerably deeper than the Silver Peak site. The age of the fill was determined to be entirely Quaternary. Also evident were geological structures bordering the basin as well as paleo-stream channels. (Nevada Sunrise Metals Corp., 2016).
The presence of these paleo-channels suggests evidence of fluid migration from Clayton Valley and Silver Peak Range rocks and a possible hydraulic connection with several potential sources of lithium-rich groundwater. It was also noted that faults significantly displaced the formations and were likely the mechanism that placed the sediments this deep in the basin. As a result, the company expanded their exploration efforts to acquire electromagnetic profiles across the basin to further delineate the stratigraphy and structure in the area, as well as for remote detection of subsurface brines. In addition, geochemical analysis of the overlying vegetation was conducted which detected lithium at surface.
Landau, Germany Case Study
The last example of a recent exploration effort comes from a project aimed at extracting lithium from an existing geothermal power site in Germany. The Landau Geothermal Power Plant was the first commercial geothermal power plant with an electrical output in the megawatt range in Germany. The plant was officially commissioned in 2007. For the first time, energy could be extracted from hot water reservoirs that were efficient and hot enough to produce a gross output of more than 3 MW. The development of the plant at that time was possible as a result of new technology development for brine injection wells.
Despite the advancement of this technology and the initiation of geothermal power in the region, competitive costs for this type of power growth and expansion were challenging. As a result, a number of geothermal sites were evaluated for lithium extraction to occur concurrently with geothermal production. The value of the lithium, if extracted efficiently, could help offset the costs of the geothermal project, and the lithium extraction process would also have access to a power supply on site for the operations.
Vulcan Energy Incorporated, the operator, acquired the Landau Plant with the aim of increasing historic brine flow rates and simultaneously extracting the lithium in the process. It is currently proposed that lithium carbonate will be extracted from these brines once higher rates are achieved and sustainable by the operator.
With traditional geothermal production in this area, there is usually a paired combination of one thermal producing well and one injection well in the initial project plan. In order to extract lithium in significant quantities, the brine flow needs to be increased. Concepts to increase brine flow, such as double completion of wells and multi-reservoir completions, are being assessed by the operator in order to extract enough lithium from the subsurface.
For 35 years, geothermal projects have been developed in this area at a depth of approximately 2 km. The deep target consists of a granitic basement and overlying sandstones which are both highly fractured and hydrothermally altered. This area differs from other areas with geothermal plays, such as volcanic-hosted ones, where the systems are more complex and in general less permeable. The lithium concentrations in these German geothermal brines have long been recognized as anomalously high. Extensive testing and analysis work by Pauwels, in 1990, indicated this would be an area of high lithium concentration in the subsurface brines. Vulcan has used estimates of approximately 180 ppm, on average, for the current resource update (Vulcan Energy Incorporated, 2023).
Due to the complexity of the subsurface, further data analysis as well as 3D seismic will assist operators in understanding brine migration, as well as heat transport, in order to identify the location and type of faults and fracture distributions as well as optimize their well drilling plans.
Lithium and geothermal projects can be combined, provided that renewable heat from the geothermal project is present, high lithium grades are available to extract, and a high brine flow rate potential exists. This also means the exclusion of fossil fuels to power the process. This innovative project is at the preliminary planning stage now and is planned to come into production in two or more years.
In summary, the main considerations and challenges for lithium exploration include sufficient and reliable data availability as well as quality interpretation of the data. If there are public databases available or existing operations within an area of interest, this can aid significantly in project initiation and shorter timelines for operations. High lithium concentrations are key to project economics, so existing data sets or a planned program to acquire additional concentration estimates is a vital component of a successful project. As well, imaging the subsurface for current and future operational efficiency is essential. There are numerous geophysical tools that can be employed to assist with this, including gravity, seismic and electromagnetic surveys. Finally, understanding the project risks and applying sufficient data interpretation to assess the total lithium resource is key to moving the project forward. This will help facilitate a final investment decision for a potential pilot project in a given area.
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Daitch, P. J., 2018. Lithium Extraction from Oilfield Brine. Master’s Thesis, The University of Texas at Austin.
Davis, J.R., Friedman, Irving, and Gleason, J.D., 1986, Origin of the lithium-rich brine, Clayton Valley, Nevada: U.S. Geological Survey Bulletin 1622, p. 131–138.
Garrett, D.E., 2004, Handbook of lithium and natural calcium chloride—Their deposits, processing, uses and properties (1st ed.): Amsterdam; Boston: Elsevier Academic Press.
Kunasz, I.A., 1974, Lithium occurrence in the brines of Clayton Valley Esmeralda County, Nevada, in Coogan, A.H., ed., Fourth International Symposium on Salt, Houston, Tex., April 8–12, 1973, Proceedings: Cleveland, Northern Ohio Geological Society, p. 57–65.
Papke, K.G., 1976, Evaporites and Brines in Nevada Playas, Nevada Bureau of Mines and Geology Bulletin 87, P. 29-31.
Pauwels et al., 1990, Lithium Recovery from Geothermal Waters of Cesano (Italy) and Cronembourg (Alsace, France), Proceedings: 12th New Zealand Geothermal Workshop 1990.
Standard Lithium Ltd., 2021, Preliminary Economic Assessment Of SW Arkansas Lithium Project, NI 43 – 101 Technical Report – Amended, https://www.standardlithium.com/investors/news-events/press-releases/detail/104/standard-lithium-files-preliminary-economic-assessment.
United States Geological Survey, 2020, Lithium. in Mineral Commodity Summaries, January 2020, https://on.doi.gov/2K3OO2S
United Stated Geological Survey, 2022, United States Geological Survey Mineral Commodities Summary, January 2022, https://pubs.er.usgs.gov/publication/mcs2022.
Vine, J.D. (1980): Where on Earth is all of the lithium; U.S. Geological Survey, Open File Report 80-1234,107 p.
Vulcan Energy Incorporated, 2023, Zero Carbon Lithium, Corporate Presentation, https://v-er.eu/corporate-presentations.
About the Author
Kathleen Dorey is a managing partner of Petrel Robertson Consulting in Calgary, Canada. Ms. Dorey leads a team of geoscience professionals at the forefront of adapting petroleum geoscience skills to new resource applications such as lithium and helium exploration, geothermal energy, and CO2 sequestration. Kathleen has an Honours Bachelor of Science degree from Western University in Canada and has worked as a geoscientist in major operating companies such as Texaco, Conoco and BG International as well as many junior energy companies. Kathleen has contributed to and presented talks and courses for the CSEG, SEG, EAGE, CEGA, CGEF, UGTF, AAPG, Petrotech and APEGA. She is currently Past President of the CSEG, was Chair of the CSEG Foundation, past member of the SEG Council, has served as a Director on the GeoConvention Board and has been a Session Chair for GeoConvention for numerous years..