The transition to a low-carbon economy requires major inputs of critical minerals such as lithium (Li), used as an electrolyte in batteries and other energy storage systems. Global lithium consumption increased by 41 % from 2021 to 2022 (USGS, 2023), and the International Energy Agency (IEA) (2022) estimates that lithium production will grow 42-fold between 2020 and 2040. The surge in demand for Li-ion batteries is spurring both global exploration for new lithium deposits and the development of more efficient technologies for lithium production and refinement. In the United States (U.S.), the criticality of lithium was officially recognized in 2017 (Executive Order No. 13817, 2017), underscoring the increasing demand amidst global bottlenecks in extraction and refining. As one indicator of the increased investment in the sector, the U.S. Department of Energy spent $1.6 billion on lithium in 2022, including mine construction, exploration, extraction and process technologies, and battery recycling (USGS, 2023). New U.S. legislation incentivizes domestic production of critical minerals such as Li, as in the Inflation Reduction Act (IRA) provision of tax credits for electric vehicles and other decarbonizing technologies that meet standards for sourcing and processing domestically or from trade partners. This new law is expected to increase the demand for Li by another 15 % (S&P Global, 2023). Most recently, three Li projects have been added to the FAST-41 Transparency Projects to streamline and increase permitting efficiency (Federal Permitting Improvement Steering Council, n.d.). Domestic manufacturing production and demand for lithium is withheld in recent federal reports (USGS, 2022(USGS, , 2023(USGS, , 2024)). However, over 25 % of lithium consumed is imported, which is a significant volume of ~3400 tonnes of lithium. Of the lithium imported to the U.S., 94 % comes from Argentina and Chile and the remainder from China and Russia (USGS, 2024).
There is only one operating Li mine and commercial refinery in the U.S. today, located in Nevada. In Utah, lithium carbonate is produced as a byproduct of magnesium at one site. The U.S. surge in exploration and project development is primarily in three categories: hard-rock mining of Li pegmatites, soft-rock mining of Li clays and sediments, and solution mining of Li brines. Many of the known lithium deposits in the U.S. are located close to or within legally-defined Native lands (Block, 2021), underscoring the urgent need to identify responsible approaches to the domestic production of critical minerals. In one such example, construction of the U.S.'s largest proposed Li mine has proceeded at Thacker Pass despite litigation by Tribes and conservationists. Recent global assessments have deliberated on both security and sustainability considerations in strategies for reshoring lithium supply chains to the Global North or politically aligned countries (Bridge and Faigen, 2022;Riofrancos, 2023). Like many mineral commodities, the diversity of Li deposit types and the variety of extraction methods are likely to play an important role in the social acceptance of operations. Responsible development of Li resources will require recognition of the interconnectedness of geological deposit type, production technique, environmental and social impacts, and public perception.
To understand these dynamics, this article is informed by a political ecology conceptual framework (Robbins, 2019). This holistic perspective calls for the examination of the relationships between environmental, social, political, and economic drivers of and impacts from resource development. Contentious or not, Li projects are the result of wide-ranging interactions among a broad set of actors, technologies, and environments (Bridge and Faigen, 2022;Wolters and Brusselaers, 2024). Drawing on this framework, our analysis highlights the deeply intertwined environment-society relationships inherent to lithium projects in the U.S., with a particular focus on the central features of Li developments, including geological endowments, extraction and production processes, and the broader socio-environmental impacts. This interdisciplinary approach integrates insights from geology, engineering, and social science to examine how resource availability, technology, and social dynamics converge to shape the outcomes of lithium development.
In this article, we first provide a general overview of the Li deposit types and production techniques, to provide an overview of geological and technical availability. We then turn to a review of former and contemporary U.S. based Li project sites, which provides the foundation for a domestic resources and reserves summary. Then we provide an analysis of many of the environmental considerations of Li extraction and processing, and public perceptions of these developments. This analysis reveals that the environmental and social impacts of Li extraction and development are highly variable across different mining methods and contexts, with significant concerns related to water use, biodiversity, waste, land disruption and community opposition, particularly when projects intersect with Indigenous lands or environmentally sensitive areas. Leveraging these technical, environmental and social discussions we develop a conceptual landscape of U.S. lithium mining, incorporating stakeholder values and global factors. This contribution fills the gap of connection and feedback, between geological and technical availability and the social and environmental availability of lithium. Furthermore, the interconnections illuminated by this work, provide the foundations and outlook for future research areas central to just U.S. lithium production.
This study reviews the U.S. sites where Li production is in progress or proposed, the major sites of Li exploration where mining is being evaluated, and sites where Li extraction and refinement is currently or would be in future associated with primary production from geological solids and fluids. The review includes recent and current projects, as well as emerging extractive technologies and stages of refinement. Project stage is classified broadly into six classes, exploration, study, permitting, development, producing and inactive. Detailed status of the main projects is explained in text, and summarized in tabulated results, and the stages are similar to those described in detail by Andrade et al. (2024). Historic sites of Li-resources have also been summarized and integrated into the discussion of domestic potential. The rapidly evolving Li exploration industry means new projects may emerge after the submission of this publication and potentially influence the overall landscape of domestic lithium supply chains. The review does not include further downstream production of batteries or other outputs. The review also does not consider recycling of Li. Recycling is not anticipated to play a significant role in supplementing lithium supplies yet, although potentially 3-9 % of global demand may be met by recycling in 2030 (Schmidt, 2023).
A deposit's mineral content is commonly reported in terms of mineral resources and ore reserves. Mineral resources are defined as a concentration of materials so that there are reasonable prospects for eventual economic extraction. Mineral resources are ranked by geological confidence from least to most as inferred, indicated, and measured. Ore reserves are the subset of mineral resources that can be economically extracted. Ore reserves are classified by their geological confidence from low to high as either probable or proven (JORC, 2012). Lithium is compared as contained lithium in metric tonnes (t) or millions of metric tonnes (Mt) in this text, converted from lithium carbonate equivalent (LCE), Li 2 CO 3 , or Li 2 O depending on the project site.
The analysis aggregates site-specific data collected between 2023 and the middle of 2024, utilizing a wide array of previously uncollated references in the public domain. The fast-evolving nature of projects and social responses to these means that a period of data collection and a wide variety of databases and search engines needed to be employed. During the period of data collection, a number of projects changed stages of exploration to study to permitting or became inactive. This constant evolution of the lithium sector in the U.S. means some data will become out of date, as projects evolve. However, this ongoing rapid evolution requires this interdisciplinary review to prevent overlooking of impacts or oversimplification of the complex challenges in the immediate future in domestic supply of lithium in the U.S. The data include project-specific technical and regulatory documents issued by the industry, reports from the U.S. Geological Survey and federal and state bodies involved in authorization of mining operations, scholarly articles, contributions to symposia and seminars, and information disseminated through press briefings and various news outlets. The discussion draws on publicly available data through a desktop study to compare the social and environmental impacts of the various proposed types of Li production. Since most of the proposed projects are new, little to no primary social science research has been previously conducted. Discussion of social acceptance (or lack thereof), paves the way for more detailed case studies of individual projects as they develop.
The global lithium market is predominantly supplied by salar brines (also known as closed basin or continental brines) and pegmatite deposits. The deposit types and associated recovery methods reviewed in this work are shown in Fig. 1. Solid Li deposits are mined using hardrock methods for pegmatites and soft-rock for clays and sediments. Solution mining methods currently include evaporation of salar brines, and direct lithium extraction (DLE) for solution-hosted Li in oil field brines and geothermal brines; DLE may be used for salar brines in future. Examples of projects in these four deposit-production types are illustrated in Fig. 2. The general global context of each deposit-production type, their geological formation and the production methods are broadly and briefly reviewed in sections 3.1 to 3.4. Deeper and global analysis of these topics and deposits genesis is explored over two recent special issues in the journal of Economic Geology, outlined in Benson et al. (2025). Some of the main factors that will affect the selection of mining method and the project economics, are grade, mineral content, shape and depth of the deposit, location and jurisdiction, compositional and mineralogical features important for processing, and possible by-products.
Hard rock mining for lithium has been conducted by open pit and underground operations at many sites around the world, accounting for 61 % of current production, mainly from Australia, and a quarter of known lithium deposits (Müller et al., 2023). These high grade and low tonnage deposits are distributed globally, including Australia, Czechia, Austria, Portugal, Germany, China, Zimbabwe, Canada and the U.S. This geographic diversity makes pegmatite deposits attractive to diversify lithium sourcing. The lithium grades in pegmatites can be significantly higher than those found in other lithium deposit types. Some pegmatite deposits report lithium oxide (Li 2 O) grades of up to 3.93 % (Bogossian, 2020). They generally range from 0.58 to 1.18 wt% lithium (de los Hoyos, 2022). Depending on the grade, size, and depth of Li pegmatite deposits, various methods have been deployed, including artisanal surface mining (Bradley et al., 2017;Garrett, 2004;Melcher et al., 2008;Mutima and Wei Li, 2010;Romer and Lehmann, 1995), large-scale open pit mining (Greenbushes, Western Australia), and underground room and pillar mining (Tanco, Manitoba, Canada).
Common processing methods for pegmatite ore include dense media separation for reject silicate gangue, flotation when specific gravities between gangue and ore is too small, and magnetic separation to remove Fe-bearing minerals prior to floatation (Bulatovic, 2015;Gibson et al., 2017;Oliazadeh et al., 2018;Tadesse et al., 2019). Heat conversion of alpha spodumene to beta spodumene is used to make the mineral more amenable to Li extraction via alkaline or acidic leaching (Garrett, 2004).
Sedimentary lithium deposits are tabular-shaped, soft rock deposits that form from the hydrothermal alteration of lacustrine or volcanic sediments to Li-rich clays such as hectorite and smectite (Zhao et al., 2023). These deposits previously accounted for ~7 % of known global lithium resources (Schulz et al., 2017). Important jurisdictions include Nevada, Utah, and Oregon, as well as Sonora, Mexico (Morland, 2022;Schulz et al., 2017). Sedimentary and clay deposits exhibit medium grades and tonnages, with typical grades of 0.24 % Li (Thacker Pass) and 0.23 % Li (Sonora in Mexico; de los Hoyos, 2022). These deposits are commonly flat-lying, near-surface, and found in basins and calderas associated with volcanic activity (Castor and Henry, 2020;Roth et al., 2023).
The soft, flat, and tabular nature of sedimentary deposits allows for low-cost open pit mining methods, with low strip ratios due to the shallow depths of formation. Open pit mining of sedimentary Li can have minimal or no need for drilling and blasting (Roth et al., 2023). Mining operations can employ excavators, dozers, scrapers, and large-size hydraulic mining shovels, such as the Caterpillar 6020B or equivalent. In some instances, a combination of shovel and continuous miner operation can be employed, particularly when the maximum open pit depth is relatively shallow, commonly less than 100 m. The two main processing routes for lithium-bearing sediments include 1) acidification and 2) salt roasting, chlorination, and alkalization (Meshram et al., 2014). Key challenges in processing clay-hosted lithium arise from the generally lower concentration, requiring processing of larger amounts of ore, as well as the refractory nature of clays to acids which makes them more challenging to process due to higher acid consumption and equipment wear (Amer, 2008). Development of more efficient and environmentally friendly processing methods for clay-hosted lithium is ongoing (Chesnutt et al., 2023;Kluksdahl, 1986).
Globally, salar brines comprise about half of identified Li resources (Schulz et al., 2017;U.S. Geological Survey, 2023). They form when meteoric fluids, snow melts or groundwaters, leach and transport Li from granites or volcanic ashes into a closed basin, where tectonic subsidence, geothermal activity and/or igneous activity are commonplace (Munk et al., 2016). Arid conditions cause extreme evaporation of the basin waters, resulting in salt flats or salt lakes at the surface and concentration of Li in an underlying brine aquifer (Munk et al., 2016). Geographically these deposits occur in South America and Asia, and the U.S. Basin and Range Province. Bolivia has the largest salar Li resource (23 Mt; USGS, 2024), which remains largely untapped. Argentina and Chile have the largest reserves; 2.7 and 9.3 Mt respectively (USGS, (Lithium Americas Corp., 2022;as cited in Roth et al., 2023). D: Lithium clay exploration drilling at Thacker Pass, Nevada (Lithium Americas, n.d., as cited in Saywell, 2018). E: Geothermal brine; artist's rendering of production facilities at the Hell's Kitchen project, Salton Sea, California (Controlled Thermal Resources Holdings, n.d.). F: Oil field brine; photograph of Lanxess South Plant, Arkansas, where Standard Lithium is conducting pilot-scale direct lithium extraction (Standard Lithium, 2024). 2023). Average Li concentrations are variable, between 1400 ppm in the Salar de Atacama in Chile, 320 ppm in the Salar de Uyuni in Bolivia and 160 ppm in Clayton Valley in the U.S (Schulz et al., 2017).
Lithium production from salar brines is primarily achieved using evaporative concentration (Kelly et al., 2021;Stringfellow and Dobson, 2021). High-Li concentration (>1000 ppm) brines are pumped from well fields and blended into large, openair ponds where up to 90 % of the brine water used is lost through evaporation (Vera et al., 2023). During evaporation across multiple sets of ponds, various salts such as magnesium chloride, potassium chloride and sodium chloride can be co-extracted. In the Salar de Atacama (Chile), spent brine is re-injected into the subsurface (Marazuela et al., 2019). The evaporation process can take between 10 and 24 months and 100-800 m 3 of water from the brine are lost to evaporation per tonne of lithium carbonate (Vera et al., 2023). Freshwater is added during processing stages from freshwater reserves, and brine extractionmay result in an drawdown and mixing if freshwater and brine aquifers are connected (Vera et al., 2023). When lithium concentration in the ponds reaches concentrations of about 6000 ppm it is extracted to be processed into lithium hydroxide and lithium carbonate. Overall recovery of evaporation methods can range from 40 to 60 % (Nicolaci et al., 2023). Evaporative extraction methods are highly dependent on hydrogeological processes that govern the brine concentration and evaporation rates. This makes the methods suitable for a small set of deposits and geographic conditions.
The drawbacks of evaporitic concentration have led to a rise in interest and investment in DLE to extract lithium directly from solutions without evaporative concentration. DLE includes a range of technologies and techniques, such as precipitation, sorption, ion-exchange, solvent separation/extraction, membrane separation, and electrochemical separation technologies (Foo and Lienhard, 2025;Fuentealba et al., 2023;Reich et al., 2023;Stringfellow and Dobson, 2021;Warren, 2021). DLE has several benefits over evaporitic methods, including higher recovery rates of up to 70-90 %, production lead times of hours to days instead of months to years, significantly lower land use (Nicolaci et al., 2023); however fresh water usage is highly variable depending on the DLE technique, in some cases this may be higher than evaporation, and energy and chemical inputs must also be considered for DLE (Halkes et al., 2024;Vera et al., 2023). Although not in large-scale deployment yet, current demonstration and pilot plants show potential for DLE technologies as an alternative way for Li recovery from salar, geothermal and oil field brine resources.
Geothermal and oilfield brines are emerging as potential sources of lithium. In 2017 geothermal brine deposits accounted for less than 3 % of global Li resources (Schulz et al., 2017) and can be geologically associated with clay, salar, and pegmatite Li deposit types. DLE technologies are being investigated for Li recovery from these sources, among which are pilot plants in operation at the Salton Sea in California and studies on Li-rich granites or pegmatites in Cornwall, UK and the Rhine Graben, Germany. However, challenges exist in implementing DLE in geothermal power plants, such as the negative impact of direct precipitation, sorption, and ion-exchange on ongoing plant operation, and difficulties with high temperatures and flow rates in membrane and reverse osmosis methods (Melnikov et al., 2017;Reich et al., 2023;Somrani et al., 2013;Sun et al., 2015;Wen et al., 2006).
Oil field brines are another candidate for the application of DLE technologies, with ongoing exploration in Arkansas, Texas, Utah, and Alberta, as well as in China (Kumar et al., 2019;Yu et al., 2023). Resources from oilfield brines can vary significantly from several dozen to several hundred thousand metric tonnes (Changes and Swiatowska, 2015;Kumar et al., 2019). Lithium production from oilfield brines involves various technologies, each with its own set of challenges. The use of adsorbents, such as ion exchange resins and metal oxides/hydroxides, can be problematic due to the high concentration of non-Li metal ions and may be sensitive to organic compounds in the brine (Knapik et al., 2023). Solvent extraction shows higher selectivity for Li but requires pretreatment to remove divalent ions and organic impurities. Membrane technology, such as nanofiltration and low-pressure reverse osmosis, can be used for Li extraction from low-concentration brines but faces challenges with membrane fouling due to organic compounds and suspended solids (Kumar et al., 2019). Differences may also occur due to extraction from the type of reservoir, e.g. unconventional shales or conventional carbonates and sandstone fields (Blondes et al., 2023). Despite research and pilot-scale implementation, DLE has not been demonstrated at the commercial scale.
The latest comprehensive cost estimates indicate that producing lithium from hard-rock mines (mainly via spodumene concentrate) costs on average about US$2540/t of lithium carbonate equivalent (LCE). This figure comes from a 2019 cost outlook by S&P Global Market Intelligence, which analyzed data from 11 operating hard-rock producers. In contrast, lithium produced from brine operations tends to have much higher cash costs-around US$5580/t LCE (Webb, 2019). Labor is the most significant cost at hard rock mines, accounting for almost 30 % of total cash costs in 2019, whereas reagents for downstream processing are the biggest cost for brine assets, estimated at 36 % of total cash costs in 2019 (Webb, 2019).
There is currently limited information on production costs for clay deposits. Based on recent feasibility studies that consider process recoveries and by-product credits, net operating costs for battery-grade lithium production can range from US$2000/t to US$4000/t LCE. For instance, Century Lithium's Clayton Valley Feasibility Study estimates that an initial "gross" cost of US$10,390/t LCE can be reduced to approximately US$4364/t LCE after sodium hydroxide credits, with a reduction as production upscales from Phase 2 at US$2491/t LCE to Phase 3 at US$2044/t LCE. These project-specific assumptions-using a long-term Li 2 CO 3 price of roughly US$20,000-US$24,000/t and an 83 % recovery rate-demonstrate that optimized clay-based lithium production can be economically competitive with other deposit types (Century Lithium Corp, 2024).
This section reviews the active, proposed, and exploration sites for lithium in the U.S. The data are presented according to the stage of activity as well as the deposit type and production method. The sites described in text are mapped in Fig. 3.
Early production of lithium in the U.S. was by hard rock mining of pegmatite deposits in South Dakota and North Carolina, as well as lithium clays at Franklin Wells in California. Annual tonnages fluctuated, with peaks during World War II and again in the 1970s when annual production reached approximately 5000 tonnes (see Miatto et al., 2020; for a review of historic Li production in the U.S.). The decline of domestic hard rock lithium mining culminated in 1998 with the closure of the last spodumene pegmatite mine, a move attributed to cost reduction strategies that shifted hard rock lithium production offshore (Ober, 1998).
Lithium brine production commenced in 1967 at the Silver Peak Mine in Clayton Valley, Nevada (Miatto et al., 2020). The Silver Peak Mine remains the sole operating lithium mine and the only commercial scale lithium refining facility in the United States today. There has been limited transparency on production rates due to the role of lithium in defense applications (Miatto et al., 2020;USGS, 2023). Available data suggest that annual production from Silver Peak varies according to evaporation pond capacity and ranged from ~3500 to ~6500 metric tonnes between 2015 and 2021 (Albemarle, 2023a). The average Li concentration is 160 mg/L and the current reserves are 68,300 tonnes of contained Li based on a mine life until 2052 (Albemarle, 2023a). Estimated mineral resources include 50,200 tonnes contained Li in the measured and indicated categories, as well as 89,500 tonnes contained Li in the inferred category (Albemarle, 2023a).
Production of lithium from the Silver Peak Mine is by pumping subsurface brine from 63 active production wells at a maximum rate of 20,000 acre feet per year. This rate is limited by the amount of water the operation is permitted to draw from the basin annually. The brine is pumped into ponds, where solar evaporation precipitates salts, mostly sodium chloride, thereby increasing the Li concentration of the brine. When the brine reaches 0.54 % Li it is pumped to the onsite carbonate plant for removal of impurities and precipitation of Li 2 CO 3 . The plant is listed as having a capacity of 6000 tonnes of Li 2 CO 3 per year, equating to about 1100 tonnes of pure Li, but it has been reported to produce slightly more (Albemarle, 2023a).
The Silver Peak operation was constructed prior to the National Environmental Policy Act (NEPA) of 1969 and was not subject to modern environmental permitting. Removal of magnesium from the brine generates solid residues of magnesium hydroxide and calcium sulfate that are stored permanently onsite in a lime solids pond, with low or non-detectable reported concentrations of potential contaminants. Mine closure plans include closure of the wells, removal of facilities, and creation of a physically and chemically stable site that will not degrade state-owned waters. The ponds will be dewatered and fenced with barbed wire to prevent access, but the area would only be capped or covered in the case of unanticipated dust hazards. Revegetation would be minimal since the area was originally a dry salt playa.
At the Great Salt Lake in Utah, magnesium has been produced by solar evaporation of salar brines since 1972 (Tripp, 2009). In 2022 and 2023, the US Magnesium facility also recovered lithium as a byproduct (USGS, 2023, 2024). Other byproducts include salts for potash fertilizer, magnesium chloride road salt, sodium chloride, and calcium chloride (Tripp, 2009). Two different sets of solar evaporation ponds at Stansbury Basin and Knolls have been used to increase the magnesium concentrations of brines from the lake. These concentrated brines are pumped into an onsite plant facility for removal of sulfate, followed by precipitation of magnesium chloride, which is dried, heated, and purified into magnesium metal. US Magnesium constructed an onsite lithium carbonate plant in 2019. The operations have capacity to produce about 64, 000 tonnes of magnesium and 9000 tonnes of lithium carbonate annually, or about 1700 tonnes of pure Li (US Magnesium, n.d.), but actual lithium production numbers are withheld as proprietary (USGS, 2023(USGS, , 2024)). Improper waste disposal techniques by US Magnesium led to the site's designation as a Superfund project while still in operation (U.S. EPA, n.d.). The Superfund testing and remediation efforts have focused on chlorine, hydrochloric acid, and organochloride compounds. At the Ogden site on the Great Salt Lake, Compass Minerals had planned to begin byproduct recovery of lithium from the brine that the company already draws for its magnesium chloride, potash, and sodium chloride salt operations. The 2023 Utah State Legislature House Bill 513 created uncertainty around the regulatory environment for lithium production, leading Compass Minerals to suspend its lithium development efforts (Compass Minerals, 2023).
Lithium pegmatites in North Carolina were mined historically as early as 1880 for gem quality spodumene, with the first major industrial production commencing in 1942 by the Solvay Process company (Broadhurst, 1956). In 1950, Foote Mineral Company acquired the Solvay plant to process ores it mined from nearby Kings Mountain, and in 1955 Lithium Corporation of America built a second processing plant in Bessemer City. This ushered in a period of significant production from the belt by several companies through the 1970s, when global Li production shifted to salar brines. The surge in Li demand is bringing new exploration interest to the Carolina deposits, and there are proposals to reopen the Kings Mountain Mine as well as a new mine in permitting stages in nearby Gaston County.
The King's Mountain mine flooded after closure in 1988, and Albemarle is pursuing permits to dewater the open pit and reopen the mine. The company has received $90 million in Department of Defense funds and is currently in advanced exploration and prefeasibility study (for resources see Table 1). Dewatering is expected to take about 18 months and is a prerequisite for further drilling and feasibility studies. The water would be temporarily stored, treated, and conveyed to a reservoir for gradual release into a creek (Albemarle, 2024). Given the existing open pit, it is likely that further mining would be by open pit methods. The company is conducting an Environmental and Social Impact Assessment and is preparing its permitting submissions. The community is divided between those who would welcome a return of the former mining economy and those who oppose the mine.
Piedmont Lithium received state permits and federal Clean Water Act permits for a proposed operation which would mine and concentrate spodumene, for onsite production of lithium hydroxide. The company proposes to produce about 30,000 tonnes lithium hydroxide per year from an open pit mine over 30 years (Piedmont Lithium, n.d.). The company completed a bankable feasibility study in 2021, based on the assumption that the facility would process spodumene from its Gaston County mine, as well as sourced from offtake agreements with other mines. Reserves and resources are shown in Table 1. Most of the known resources lie within 150 m of the surface. Mining would be by conventional drill and blast, followed by conveyor transportation to an onsite processing facility where it would undergo crushing, dense media separation, and grinding to produce a spodumene concentrate. Flotation would be used to quartz, mica, and feldspar byproducts. Lithium hydroxide would be produced by soda leaching, followed by conversion, and ion exchange (Piedmont Lithium, 2021). Piedmont also received $142 million from the Department of Energy for construction of another processing plant in Tennessee, to process spodumene from a mine in Ghana where the company holds an offtake agreement. The facility would have the same capacity as the proposed processing plant in North Carolina.
Pegmatites were historically mined for feldspar in Maine's Oxford district, where recent exploration has identified what may be the highest-grade Li pegmatite in the world at about 4.7 wt% Li 2 O (Simmons et al., 2020). The Plumbago North could be the world's third largest in pegmatites (resources in Table 1), behind Australia's Greenbushes and Mount Marion (Simmons et al., 2020). Mining policy in Maine has deterred further exploration. In Arizona, pegmatites were mined for Li in the San Domingo area of Maricopa and Yavapai counties in the 1940s and 1950s. Renewed exploration and two seasons of recent drilling have identified short intervals up to about 1 % Li 2 O, and preliminary mineral processing test work has been done (Bradda Head Lithium, n.d.-a).
About 74 % of known Li resources and 72 % of known reserves in the U.S. are in lithium clay and sedimentary deposits. There are numerous sites of exploration, the majority of which are in Nevada. One permitted mine is under construction at Thacker Pass in Nevada, and one proposed mining project is in permitting stages at Rhyolite Ridge in Nevada.
In 2023, Lithium Americas Corporation began mine construction at Thacker Pass. The processing facility will produce 40,000 tonnes per year of lithium carbonate in Phase 1, with a plan to scale up to 80,000 tonnes per year in Phase 2. In 2021, the project received its Record of Decision from the Bureau of Land Management approving construction of Phase 1, Phase 2, and a 40 year mine life. The Record of Decision was challenged by environmental and indigenous groups. A lawsuit against the mine by the Reno-Sparks Indian Colony, the Burns Paiute Tribe, and the Summit Lake Paiute Tribe was subsequently dismissed by the U.S. District Court in 2023.
Exploration has been ongoing in the McDermitt caldera since 1975, with recent drilling commencing in 2017. Lithium Americas Corporation used 366 diamond core drillholes to establish reserves, which are shown along with resources in Table 2. The average grade of the deposit is about 2000 ppm Li, with the shallower parts of the deposit dominated by lower grade smectite clays and the deeper illite-rich portions containing higher Li grade. Recent geological studies have investigated the origin of the lithium-rich clays (e.g. Castor and Henry, 2020). The soft, flat-lying claystone would be mined using hydraulic excavators, with no blasting required. The shallow open pit would comprise benches 50 m wide and 5 m tall, at a total average depth of about 300 feet. The material would be loaded into haul trucks and delivered to a stockpile for blending from the two clay zones to achieve a target grade before processing. At the on-site processing facility, the material would be crushed and dewatered before undergoing purification and lithium carbonate precipitation. The purification step involves lime treatment that produces filter cake and salts of magnesium, sodium, and potassium that would be stored in a clay stack facility that would undergo progressive reclamation during mining. General Motors has a 15-year offtake agreement for 100 % of Phase 1 production.
The Rhyolite Ridge lithium-boron sedimentary deposit in Nevada is currently in permitting stages, and the Environmental Impact Statement was released in April 2024. Ioneer has completed baseline studies and submitted both initial and modified Plans of Operations to the Bureau of Land Management. Lithium resources are stated in Table 2 and additional boron resources are reported as 14 Mt boric acid (Ioneer, n.d.-b). Production is forecasted at 22,000 tonnes lithium carbonate and 174, 400 tonnes boric acid per year over a 26-year mine life (Ioneer, 2020). Mining would be by drill and blast, with ore trucked to an on-site processing facility for crushing and vat leaching. Ioneer's lithium-boron production and refining process involves vat leaching to generate a pregnant solution nearly saturated in boricc acid, which would be treated by cooling crystallization, evaporation and upgrading to produce boric acid. The lithium brine will be purified, and precipitation will be used to produce high-purity lithium carbonate. The off-grid processing plant will be powered by steam and emit no CO 2 (Ioneer, n.d.-a). Project funding is expected to come from a $490 conditional equity commitment from the private mining company Sibanye-Stillwater Ltd and a $700 million conditional loan commitment from the Department of Energy.
Lithium clay resources have been defined at several sites in Nevada, California, and Arizona. In Nevada, these include Bonnie Claire, the Lithium, n.d.-c). Also in Arizona, the Big Sandy project has indicated and inferred resources (Table 2; Arizona Lithium, nd).
There are numerous sites of early-stage exploration for Li clays in Nevada. No major results have yet been reported for the Halo, ELi, Green Clay, and Clayton Ridge projects. Two holes have been drilled at Kibby Basin, a playa about 60 km north of Clayton Valley. The drilling intersected over 1500 feet of clay containing several hundred parts per million Li as well as similar Li concentrations in groundwater (Belmont Resources, n.d.). Belmont Resources obtained water rights for 2896 acre feet annually for brine pumping and processing at Kibby Basin, equivalent to about 10 % of the Silver Peak water allocation. It is currently unclear whether the site would be a clay mining or brine target, or both. In the Amargosa Valley, surficial samples from the company Rover's exploration site contain 700-900 ppm Li (Rover Critical Minerals, n.d.). Some of the company's proposed drill targets are only a few thousand feet from springs in the Ash Meadows National Wildlife Refuge, prompting a lawsuit led by the Amargosa Conservancy (Center for Biological Diversity, 2023).
About 1 % of U.S. Li resources and 13 % of the reserves are in salar brines. Silver Peak is the only site currently in production, and basins such as Clayton Valley and Armagosa Valley in Nevada, and Panamint Valley, Dry Lake Basin, Bristol Lake, and Salton Valley in California are foci of past or ongoing exploration projects.
In Clayton Valley (NV) seven brine projects are under exploration adjacent and nearby to Silver Peak Mine. By land area, the largest are Clayton Valley North, Clayton Valley South and the original Pure Energy claim (now Lithium X/Pure Energy), see Table 3 for resource summary. Pure Energy in partnership with Schlumberger New Energy Venture, received construction and operation permits for a DLE pilot plant in March 2023 (Pure Energy Minerals, 2023). The other brine projects in Clayton Valley are in early stage exploration and resource estimates are not yet available, except for the ACME project (Table 3).
Other locations in Nevada include the Jackpot Lake Project in Dry Lake Basin, which has an average Li concentration of 334 ppm, up to 820 ppm in shallow soils (Usha Resources, 2023). In both Lander and Nye Counties (northeast of Clayton valley) multiple projects are under exploration, including Amargosa project (BMR corp.), Eureka project and Wilson Salt Flats project (Bradda Head Lithium Ltd). In California, Searles Lake had historical production from 1930's to 1978, but is not currently active as brine reserves were depleted (Tahil, 2008). Panamint Valley (CA) had early-stage exploration in 2019, which currently continues in early exploration under the Liberty Lithium Brine project (owned by QX Resources). The Bristol Lake, Mojave Project (Standard Lithium, n.d.-b) has option agreements with industrial mineral producing operators. The agreement will allow for use of existing infrastructure and permitted brine processing, which has been operating for two decades. This project is considered an industrial brine project, although the brine source is salar brine (Standard Lithium, n.d.-b). (Dobson et al., 2023). The Hell's Kitchen project (CTR) is expected to produce 25,000 tonnes LCE per year (see Table 4 for resource estimate; Iyer and Kelly, 2022). The proposed geothermal power plant will have a capacity of ~50 MW. CTR expects to develop a total of seven project stages to produce 350 MW, and LCE to 175,000 tonnes per year. An Environmental Impact Report (FEIR) was completed for the Project in December 2023. This projected was officially permitted by the Imperial Country on 26 January 2024. Litigation was brought against the County by a local organization after a 15-day extension of the litigation filing deadline (The Desert Review, 2024;Wilson, 2024). This legal action was dismissed and denied by the Imperial County Superior Cout in 2025. CTR plans to commence construction activities in 2025.
The ATLiS project (EnergySource Minerals) at the Salton Sea is associated with an adjacent geothermal power plant (HR1). The proposed project will produce lithium hydroxide with its proprietary Adsorption Desorption (ILiAD) technology for an initial operation of 9 years and projected life of 30-40 years (County of Imperial, 2021; Iyer and Kelly, 2022). The procedure involves the removal of iron and silica as a waste stream, then zinc and manganese as by-products, after which lithium chloride extraction commences in a nearby area from the purified brine with ILiAD, before being purified and concentrated (County of Imperial, 2021). The annual expected production of 13,000 to 20,000 metric tonnes (Iyer and Kelly, 2022). Conversion of LiCl to lithium carbonate and lithium hydroxide will also occur in a production facility onsite. Extraction of Fe-SiO 2 may also be considered an additional product in the future, with potential to produce 136,200 metric tonnes annually (County of Imperial, 2021). In 2023, EnergySource Minerals entered a contract with Ford to supply their lithium based on anticipated operations starting in 2025 (Reyes, 2023), the project is permitted, and production is planned in 2025 (Howard Center for Investigative Journalism, 2024).
Oil field brines, also known as continental or formational brines, contribute ~6 % of Li resources (1.8 Mt contained lithium) and ~5.5 % i = inferred resources, A = annual estimated production.
of reserves (3.9 kt contained lithium) in the U.S. These values are based on the project values only, and do not include the recent assessment of the entire Arkansas Smackover resource by Knierim et al. (2024) who estimate a state-wide resource between 5 to 19 Mt of Li. Areas of potential have been identified mainly in the Smackover Formation (Table 5) as well as a few other sites in Utah, and the Marcellus Shale in Pennsylvania (e.g. Blondes et al., 2023;Mackey et al., 2024). Similarly to geothermal brines, these brines must be brought to the surface, lithium extracted at relatively fast rates and then the Li-free brine injected back into the formation. Discovered in 1922 for oil exploration, the Smackover Formation is a thick carbonate aquifer that extends from the northwestern edge of Florida westwards, through southern Mississippi, Arkansas, the northern edge of Louisianna and into the middle of Texas. A large database of petrophysical, geophysical, and geological data exist due to the extensive network of existing oil and gas wells. In Arkansas, the Smackover has also hosted an active brine processing industry for large scale bromine extraction for 50 years, resulting in state policy for brine re-injection known as a Class V permit (Heaton and Rhymes, 2023). Across the formation, there are six projects in Arkansas and one in Texas, with the highest measured Li-bearing concentration in the East Texas project at 634 mg/L (Standard, 2023). Three projects are in early exploration and the other four have LCE resources of ~8.8 Mt (includes measured, inferred and indicated metrics; Table 5).
The most advanced oil field brine Li project is the LANXESS South Plant, which currently extracts bromine. Here Standard Lithium has had a DLE demonstration plant in operation since 2020, extracting brine and converting it to lithium chloride solution (Gay et al., 2023). The project is in early permitting stages to widen the LANXESS reinjection license to include the lithium facilities. An annual production of 5400 tonnes LCE at 227 mg/L lithium brine and 135,000 tonnes over the 25 year operating life is expected, with extended operation up to 40 years (total reserves in Table 5). The existing infrastructure of the bromine recovery will aid in Li recovery by supplying the bromine-depleted brine into the lithium extraction plant. Lithium Selective Sorption (LSS; Koch Technology solutions) will be used to produce lithium chloride solution with an expected recovery of 93.1 %, which must then be converted to lithium carbonate. The bromine-and lithium-free brine will then be returned for reinjection into the existing LANXESS disposal wells (Gay et al., 2023).
The South West Arkansas Project (owned by Standard Lithium Ltd.) is in feasibility study stage and estimates are for an annual 30,000 tonnes of lithium hydroxide with a mine life of 20 years, starting in 2027 (Gay et al., 2023). Also in Arkansas, lithium leases include those by Albemarle Corporation, Tetra Technologies, ExxonMobil and Pantera Minerals are at various exploration stages with some pilot plants for DLE. The Magnolia facilities owned by Albemarle Corporation do not currently extract lithium but a DLE pilot facility is under construction alongside the bromine extraction (Scheyder, 2023). ExxonMobil recently acquired the 4 Mt LCE resource and 120,000 acre project from Galvanic Energy in early 2024. The only current Texas project (Standard Lithium Ltd) is also at exploration stage (Table 5).
Outside of the Smackover Formation, thus far only the Paradox Basin has advanced exploration for lithium in oil field brines. The Paradox Basin project in Utah ( A1 Lithium, 2022) expects to produce 13′074 tonnes per year of lithium carbonate with a 10-year initial project life and is currently expanding the project to find additional resources. About 5.27 Mt of bromine resources (inferred and indicated) are also estimated at the project. The Lisbon Lithium Project is in early exploration also in Paradox Basin (owned by American Battery Materials).
Li-extraction from shale gas wastewater is also being trialed. For example, waters from the Marcellus Schale (PA) contain on average 95 mg/L Li (Mackey et al., 2024;University of Houston, 2022). Between the Bakken, Permian Midland, Permian Delaware and Marcellus areas the projected lithium resource potential reaches ~727 Kt Li (Mackey et al., 2023), and therefore this may be targeted in the near future (Kumar et al., 2019).
This section analyzes the environmental impacts and social acceptance of the lithium projects reviewed in Section 4, using the framing of lithium deposit type.
Lithium pegmatites can be mined using either open pit or underground methods depending on the grade, tonnage, morphology, and depth of the specific deposit, leading to differential environmental impacts. In San Diego, California, small underground excavations have been used to mine for gem-quality pegmatite crystals (Bradley et al., 2017), with relatively little environmental impact given the small scale of the activity. Large-scale underground mining of Li pegmatites is currently only employed at the Tanco mine in Manitoba, Canada. The room-and-pillar underground operation has a small surface footprint, and the environmental impact assessment indicated minimal impacts on air quality or the human environment (Tetra Tech, 2011). The primary impact is an increase in suspended solids and phosphorus content of the discharge from the tailings facility, leading to algal and zoobenthic growth in the local lake. Most Li pegmatite deposits will be mined by open pit, leading to large-scale landscape disruption, the long-term consequences of which can be mitigated by backfilling and revegetation during reclamation. Historic mining of the King's Mountain pegmatites in North Carolina did not include backfilling. This led to eventual flooding of the open pit that Albemarle plans to dewater, similar to a proposal at Tanco that has led to concerns over water quality (Dawkins, 2023). Monitoring will be necessary to ensure that dewatering does not affect local groundwater, and the pumped water from the pit will require treatment prior to discharge. Lithium pegmatites are primarily made up of minerals that are environmentally benign (Bradley et al., 2017), and these deposits present little risk of acid mine drainage because of their low sulfide mineral content. The state of Maine's 2017 mining law prohibits open pit mines of more than three acres, storage of wet mine wastes (for example slurry tailings in a tailings pond), or any projects that would require water treatment in perpetuity. The law was developed partly in response to historic acid mine drainage from sulfide mining but will likely prohibit mining of Li pegmatites, despite the low risk of acid mine drainage from these deposits. Weathering of the pegmatite minerals can release elements into water, particularly if processing water is not contained and treated. Processing of lithium pegmatites typically is by alkali salt roasting. This method is energy and reagent intensive, requiring high temperatures and the use of lime to create alkali conditions. Piedmont's processing facility in Tennessee will employ alkali pressure leaching on Li pegmatite ores to reduce emissions and solid waste (Piedmont Lithium, 2023).
Soft rock Li mining is generally by open pit, leading to landscape disruption until backfilling and reclamation. The arid climates in which these deposits form can create distinct challenges for both water use and water quality, fugitive dust, and sensitive habitats. At Thacker Pass, the clay deposits will be mined by shallow open pit in blocks and then actively reclaimed (Roth et al., 2023). Once one block is mined to the bottom, mining will move to the next block, while backfilling begins in the previously mined area. Stockpiles will be contoured and seeded with native grasses. The Thacker Pass operation is designed as a zero liquid discharge process, which will involve recycling of about 85 % of the total water used. The mine will consume 2850 acre feet per year, about the same amount of well water annually as five alfalfa irrigation pivots. In Nevada at the Rhyolite Ridge deposit, a rare flowering plant known as Tiehm's buckwheat occurs exclusively in that area and was designated as an endangered species in 2022 (Ioneer, n.d.-c). Ioneer has committed more than $2.5 million to date and an additional $1 million annually to protect the plant.
Acid leaching at moderate temperatures has emerged as a preferred method for sedimentary, clay-hosted lithium due to its lower cost and high lithium recovery (Zhao et al., 2023). Rhyolite Ridge will source elemental sulfur to make sulfuric acid in a plant on site, which in conjunction with a steam turbine will provide electricity to power the operation. Soda ash is used to precipitate lithium carbonate and lime is used to neutralize the solution. These reagents require local quarrying operations or potentially emissions-intensive transportation to the processing facility. The tailings can be filtered and stacked, although surface water must be managed and diverted. Process water is a precious resource in the arid environments where Li clay deposits form, creating potential conflicts with other activities.
For solution mining and evaporative concentration of lithium, the primary areas of environmental impact are related to water use, water quality and land use. Salar brines form due to aridity and are by default found in water stressed regions. Kaunda (2020) also argues that trace amounts of Li in wastes could also hold significant impacts on the environmental health of the region, in particular for air water, and soil. In the South American context, salar Li production has been highly criticized over use of scarce water resources, ecosystem impacts, and the production of vast amounts of waste (Liu et al., 2019;Marconi et al., 2022;Vera et al., 2023). To precipitate the salts and obtain Li, up to 95 % of the brine water must evaporate (Flexer et al., 2018). The remaining water is highly concentrated in salt, up to 9 times the average of sea water, thus making it unsuitable for human and animal consumption or irrigation, along with salt residue waste. However, fresh water use for production of concentrated lime solution and purification of lithium carbonate raises concerns. Between 22.5 and 50 m 3 of freshwater are needed to produce one tonne of battery grade lithium carbonate (Baspineiro et al., 2020;Vera et al., 2023), the upper part of this scale is largely dependant on if evaporated water from the brine is counted as freshwater use. As the brine is drawn from the aquifer, used and evaporated at 100-800 m 3 per tonne of lithium carbonate, drawdown of neighboring freshwater aquifers could cause freshwater aquifer degradation and impact on ecosystems and the communities depending on this water (Vera et al., 2023). The production of one ton of Li 2 CO 3 by water evaporation is estimated to result in about 115,000 kg of waste (Flexer et al., 2018). Although considered non-toxic, such amounts will have significant impacts on waste management systems in the vicinity of the points of extraction. Finally, direct land use impacts have been found to be a core issue of evaporitic brine extraction (Mousavinezhad et al., 2024). Salar specific hydrogeological research and water assessment criteria are called for by recent studies (Foo and Lienhard, 2025;Halkes et al., 2024;Vera et al., 2023), which will become even more critical as multiple companies compete to extract from the same reservoirs.
Relative to other methods of Li production, DLE is considered low impact at global and domestic scales, particularly due to low land surface usage, co-production potential of energy or heat, use of onsite geothermal energy to meet Li-production energy requirements and the possibility for low freshwater use (Busse et al., 2023;Vera et al., 2023). However site-specific impacts and the different DLE techniques energy and freshwater needs must be carefully evaluated and more data made available (Halkes et al., 2024;Vera et al., 2023). The volume of freshwater used varies over a large range from <1 to >1000 m 3 per tonne of lithium carbonate, reviewed over 30+ reported works on research, pilot and demonstration plants by Vera et al. (2023). One site at the Salar del Hombre Muerto has both DLE and evaporation techniques and a reported average water use of 71 m 3 per tonne of lithium carbonate, higher than Salar de Atacama at 22.5 m 3 per tonne of lithium carbonate. Although DLE may cause water issues in extremely water stressed sites, careful planning for locality and the specific technique used make it an important production technique in the future of lithium. Geothermal Li production may generate useable energy, and in the case of oilfield brines there is a potential benefit to repurposing oil and gas extractive infrastructure and waste streams for the green transition. However, pumping and reinjection may have impacts on the quality and characteristics of the geothermal brine or oil field brine reservoir. This includes effects on production from neighboring geothermal energy and lithium producers tapping into the same reservoir, depletion of the reservoir resource (heat and/or oil), seismic risk, and well integrity. In the Salton Sea, air quality, water use and energy consumption need to be evaluated across the 11 active geothermal energy and 3 planned Li production projects (Busse et al., 2023;County of Imperial, 2021, 2023). Water use is a particularly important factor. The planned projects have been projected to consume ~3 % of the historic regional water supply sourced from the Colorado River, but the cumulative effects and acceptable use may change with ongoing drought as well as irrigation usage (Dobson et al., 2023). Long-term effects also need to be addressed. For example, if the Salton Sea continues to dry up, natural CO 2 emissions from the dry lakebed will increase (County of Imperial, 2021;2023). Biodiversity is a key priority in the Salton Sea, where rare pupfish, white ibis, and other species may be impacted by construction and operations (County of Imperial, 2021; 2023). Geothermal precipitates (scaling) in the pipes may contain arsenic, barium, and lead, requiring monitoring and disposal. Similar to the other types of Li production, dust and vehicle emissions from operations may need to be monitored and mitigated, as well the cumulative impacts from neighboring sites. In oil field brines environmental hazards such as hydrogen sulfide and radium are also being evaluated (Rowan et al., 2011; U.S. EPA, 2018; U.S. OSHA, n.d.).
Extractive projects are commonly contested or accepted based on community perceptions of the impacts on the environment, local livelihoods and well-being, and perceptions of the ways in which costs and benefits are distributed (Controlled Thermal Resources Holdings, n.d.). In the case of lithium production, acceptance or opposition will be partly driven by the type of production, as well as the particular environments and communities in which each production type is centered. Until a few decades ago, the U.S. was the largest producer and consumer of lithium worldwide (Miatto et al., 2020). Thus, the industry is not new, but the technological needs of energy transitions are compounding the amounts required and shifting the locations into which both exploration and development are moving.
The response to proposed open pit mining of Li pegmatites in North Carolina and Maine builds on histories of mining in the two states. The Kings Mountain project, near Charlotte, NC, produced Li until the 1980s when it was closed because of a lack of demand. Located in a predominantly white, manufacturing community with lower median households income than the U.S. average (U.S. Census Bureau, 2023), the proposed reopening has received opposition from neighbors, over concerns around pollution, soil erosion, and water contamination (Rappeport, 2023). Nevertheless, the Department of Defense provided $90 million to the company to promote Li production (Overton, 2023). In the case of Piedmont, the company has been struggling to gain approval in both the community and with permitting officials to develop the operations (Rappeport, 2023). The company's plans include four open pits, each around 500 feet deep. While some members of the community have sold their lands to the mine, others criticize Piedmont's project. The Stop Piedmont Lithium group launched a petition against the project in 2021, which outlined how property values and water would be impacted by mining activities, including blasting, dust, and noise and light pollution (Baldwin, 2021). On the political side, county commissioners have largely opposed the project and so far, failed to rezone the area (Sorg, 2023). In parallel, in Maine, the discovery of Li deposits has also faced significant opposition, in particular linked to open pit mining methods. The state has some of the strictest mining laws in the country with high water standards and a prohibition on developing open pit mines larger than three acres (Semuels & Cough, 2023). Nearby towns overwhelmingly voted against the development of industrial mining, including through a 180-day Mining Moratorium Ordinance (Penobscot Bay Pilot, 2023). In early 2024, however, in a small win for the mining proponents in Maine, the State's Board of Environmental Protection agreed to loosen its regulations to allow for testing proving that the projected operation does not have the potential to violate state water quality standards or expose radioactive materials. If successful, this could lead to the opening of a mine (Overton, 2024). While an important step, the road to opening the operation is still long and so far, unpredictable.
Thus, the reception of the two proposed Li pegmatite mining projects has been largely negative. The projects are criticized for the environmental and livelihoods impacts and follow similar concerns seen with other mineral types. While the federal government is pushing for the development of deposits, local communities are in both cases largely opposed to the projects. In regions with relatively dense populations, such developments are likely to encounter hurdles and increased visibility.
Development of the open pit mine at Thacker Pass has been contentious. Lithium Americas began mine construction in 2023. This follows the signing of a community benefits agreement (CBA) with the Fort McDermitt Paiute and Shoshone Tribe in 2022 covering economic and cultural topics and full permitting from local, state, and federal authorities. Fast tracking of the project by the Bureau of Land Management (BLM) under the Trump administration has since been criticized by Paiute and Shoshone communities arguing that they have not been properly consulted. For groups of Indigenous tribe members, the projected operation stands on, or in close proximity, to the site of an 1865 massacre of Paiute men, women, and children by the U.S. Army. This appears supported by first-hand accounts of the events (Haywood, 1929, p. 26-29). For the mining company, the Environmental Impact Statement and the cultural inventory overseen by the BLM did not uncover remains or funerary items. Members of the Fort McDermitt Tribe, signatory of the CBA, subsequently called for rescinding the permits in a letter to Secretary of the Interior Haaland (Reno-Sparks Indian Colony & Summit Lake Paiute Tribe, 2023, p. 81-84). Since 2021, the Reno-Sparks Indian Colony and Summit Lake Paiute Tripp (2009) have intended to slow the project by requesting that the area be designated on the National Register of Historic Places. A series of lawsuits were dismissed at the US District Court level and the US Circuit Court of Appeals (Solis, 2023;Sonner, 2023b). Nevertheless, the Indigenous opposition to the project has been growing and becoming increasingly vocal. In parallel, environmental NGOs who argue that the mine would endanger old growth sagebrush, golden eagle nests, or endemic spring snails, have also joined the opposition to the mine (Fuller et al., 2021), and a rancher contested the BLM permitting through courts (King, 2021).
Public opposition to Thacker Pass follows narratives of both environmental justice and ecocide (Rodeiro, 2023), setting the stage for other social conflicts surrounding lithium mining development in the U. S. Despite piloting the Initiative for Responsible Mining Assurance (IRMA)'s self-assessment, Lithium Americas' engagement with its Indigenous stakeholders is proving complex (Lithium Americas, 2023). Through a Nevada-wide sample of respondents, Uji et al. (2023) found that people living closer to the proposed mine were more inclined to support its development. In particular, they noted that the implications for national security (U.S. independence from foreign supplies) was the only framing that increased support for the project; however, the study did not address Indigenous-related topics. Perhaps more than any other critical mineral, the push to create a domestic supply of lithium is criticized as green colonialism (Clayton and Derico, 2023). The Thacker Pass project spurred the organization of opposition movements spanning both social and environmental spheres, as well as movements such as the Astsa koodakuh wyh Nuwu, or People of Red Mountain.
The Thacker Pass case is by far the most visible demonstration of opposition between Indigenous communities and lithium mining in the US. Other cases exist, such as in Arizona, where the Navajo-owned Navajo Transitional Energy Company has a service agreement with the lithium company exploring in the Big Sandy River Valley, whereas the Hualapai Tribe has raised concerns over the potential impacts to sacred hot springs (Kapoor, 2021). The overlap between Indigenous communities and lithium projects has been at the fore of research on socio-economic impacts of these operations. In the context of the US, an estimated 79 % of lithium reserves and resources are located within 35 miles of Native American reservations (Block, 2021). Smith and Smith-Garcia (2024) found that 12.5 % of 72 lithium projects are located within 10 miles of tribal lands, with Nevada concentrating the largest number of these projects (see Map 1 -Smith and Smith-Garcia, 2024). Globally, Owen et al. (2022) estimates that 85 % of lithium reserves and resources are on or near Indigenous lands. Beyond the strict approach to legal status through sovereign reservations, lithium mines also have the potential to impact lands, landmarks, and landscapes outside of tribal lands but of religious or social significance to Indigenous communities.
Salar and geothermal Li brine projects currently under development in the U.S. have raised some socio-political concerns linked to potential environmental footprints and technical impacts. Projects in California's Salton Sea have been described as the greenest and most productive lithium projects, capable of supplying all of US needs as well as 40 % of the world's current demand (Brigham, 2022). In a county with 86 % of population identifying as Hispanic or Latino and more than 21 % of the population considered in poverty (U.S. Census Bureau, n.d.), the projects constitute economic opportunities. Neighboring communities that hope for more employment in a region marked by the exodus of younger generations generally support the projects of the three companies (Table 4). Thus, the economic benefits appear to be at the fore of the concerns of residents of the region where unemployment rates reach 12 %. However, the Salton Sea also has been at the core of environmental concerns in the state, as the water is drying up. Environmentalists hope that the new focus on the region, with the development of the mining industry will increase the visibility of these issues (Brigham, 2022). They lobby for the creation of lower-salinity ponds on lakebeds where fish and bird species could repopulate (Parker, n.d.).
Opposition is fiercer in Nevada's Railroad Valley where social and politico-technical concerns have been raised. The National Aeronautics and Space Administration (NASA) opposed the development of the mine as the region is used for accurately gauging the time it takes for satellite signals to travel to Earth and back (YaleEnvironment360, 2023). The move forced the BLM to withdraw 36 square miles of federal lands from mining to preserve the area for satellite calibration (Sonner, 2023a). In South America, solution mining is widely criticized in the Lithium Triangle in Argentina, Bolivia, and Chile for its competition with Indigenous landowners, including through the use of land and water resources. Researchers illustrate the pressure on socio-eco-systems in the region and the growing conflictual relationship between communities and lithium extractivism. In part, the state retrenchment from its role of guarantor of Indigenous rights, at least until 2019 (Ciftci and Lemaire, 2023), paralleled the sudden boom of lithium mining for the green transition and the promises of development without consideration for unintended consequenceshere on Indigenous dispossession. Dorn et al. (2022) described processes of power and environmental and economic marginalization of Indigenous communities in Argentina and Chile, the two main producers of lithium in the region. The area has been described by researchers as being "ecologically exhausted" due to the impacts on water usage rights and the impacts of chemical extraction and processing (Blair et al., 2023). A recurring tension appears to be located, in part, within the regulatory systems and their conceptualization of water as property (Lunde Seefeldt, 2022). The comparatively limited social opposition to solution mining of Li in the U. S. may reflect lack of research relative to Li production in Latin America. While pressure on Indigenous communities' historical lands is evident, other concerns should be explored to address the full scope of the social impacts.
What does a just domestic lithium supply chain look like? The answer largely depends on stakeholder values and the ways in which they interact with available resources, production methods, environmental, economic, and social impacts, domestic policies, and global factors. These complexities are summarized in a conceptual map of the landscape for lithium production in the U.S. (Fig. 4). Fig. 4 shows a selection of potential U.S. stakeholders and possible values as the central focal point of the conceptual landscape. Values are fundamental drivers for decision making (Coy et al., 2021). Values are dynamic and subjective and may have different meanings for different stakeholders (Coy et al., 2021). Values can be linked to deposit and production type, given the environmental impacts of extracting and processing different ore types described in Section 5. The domestic policies field includes aspects of lithium production that are operationalized and institutionalized within various levels of governance. The rapidly evolving lithium landscape means that project status and site-specific impacts are dynamic, yet these domestic policies and their intersections with exploration and production and stakeholder values will remain important in the lithium space. Finally global factors in the outmost region will influence domestic lithium supply chains.
The geological processes of Li enrichment have led to several districts where there is significant Li endowment, leading to regional centers of Li exploration activity. The Basin and Range province in the Western U.S. is one such regional center, with clay, salar, and geothermal potential. The pegmatite belts in North Carolina are another regional center of Li exploration. Lithium exploration is also concentrated in oil-producing regions such as the Smackover in the southeast and the Paradox Basin in Utah, with potential for increased exploration in the Bakken Shale in the Dakotas, the Marcellus Shale in the Appalachian Basin, and the Permian basins in Texas and Delaware.
When predicting where Li extraction will occur in the U.S., it is important to consider that only a fraction of the known deposits in these regions will contain resources sufficient to motivate proposals for development. Exploration is a business in and of itself, and only a small percentage of metal exploration projects meet technical, economic, and legal criteria for feasible development. Some districts may be more geologically favorable for high Li concentrations or large tonnages, leading to geographic regions where proposed or active Li developments are located. Most of these regions are geologically favorable for one type of Li deposit, meaning that within each region the proposed developments will likely utilize similar production methods. Each production method will lead to potentially similar environmental and social impacts but with different severity. For example, any proposed developments in the Carolina pegmatite belt are likely to involve hard rock mining, whereas in the Smackover Formation, the proposed developments all involve solution mining of oilfield brines. The Basin and Range Province is an exception, where the lacustrine evaporite Li mineral system (Hammarstrom et al., 2023) has potential for three deposit types and associated production types: solution mining and evaporative concentration or direct lithium extraction from salar brines, soft rock mining of Li clays, and direct lithium extraction from geothermal brines. The Basin and Range is characterized by a low-latitude dry belt across California, Nevada, and Arizona. Numerous basins formed during tectonic extension of the region, providing a unique setting that is conducive to lithium enrichment (Snow and Wernicke, 2000). The volcanic rocks are noted for their lithium-rich composition (Munk et al., 2011), leached by snowmelt, with the region's aridity leading to both salar deposits and Li clays, and geothermal activity generating the Li enrichment in geothermal brines. Geological studies that create basin scale models (e.g. Coffey et al., 2021) play a key role for understanding cumulative resources. The region's aridity also creates tension around water usage for solution mining as well as for processing of Li clays.
The geographic distribution of Li production in the United States will also be governed by policies that either support or hinder development. Although federal funding is being granted to support the development of portions of the Li supply chain, some deposits will face challenges at other jurisdictional levels. For example, the pegmatite deposits in Maine will be difficult to develop due to the state's 2017 metallic mining law. Other state policies have incentivized development, for example in the case of brine law in Arkansas (Heaton and Rhymes, 2023), which paved the way for the lithium industry growth there, more than the neighboring states. This is reflected with the majority of the Li brine exploration and advanced stage projects located in Arkansas (6 out of 7), and one in Texas, with none in Mississippi or Florida despite the geologic continuity of the Smackover Formation into these regions.
In 2024, the U.S. has a resource of ~27.91 Mt and reserve of ~0.7 Mt contained lithium, for a total of 28.51 Mt contained Li. Fig. 5 summarizes the combined total resources and reserves, and the distribution among deposit types and project stages, from the 42 projects reviewed. Only 27 of these projects have defined resources and/or reserves, primarily those projects in study, permitting, construction and producing stages.
Resources and reserves are dynamic, and these values are expected to change quickly due to the large number of projects in exploration. Companies are in the process of conducting drilling and characterization to define resources and convert resources to reserves, which will lead to increases in total Li in both categories, as well as shifts in the proportions between categories. Other formation wide estimates e.g. Knierim et al. (2024) of the Smackover formation in southern Arkansas (5-19 Mt Li) would significantly increase the contribution of oil field brine resources and total U.S. resources presented here. The USGS (2024) Mineral Fig. 4. The U.S. lithium landscape, a conceptual visualization that captures the complexities in the upstream lithium supply chain. The inner circle shows examples of potential U.S. stakeholder groups. The second circle shows example values that could be identified by stakeholders. These values are impacted by lithium production types, which are linked to the deposit types. The outer shaded circle shows domestic policies that will shape the landscape of domestic lithium production. The outermost large gray circles show global factors that influence and are influenced by lithium production. Commodity Summary published in January lists a domestic resource of 14 Mt, which includes measured and indicated but not inferred resources. The reserve value reported here (0.7 Mt) is lower than USGS (2024) value of 1.1 Mt, which likely results from the dynamic nature of resource and reserve numbers.
Most of the currently known resources and reserves are from sedimentary and clay deposits (76 %). Brines collectively comprise about 20 % of known resources and reserves, mostly in the geothermal category (11 %), followed by oil field brines (6 %) and then salar brines (3 %). Pegmatites make up only 3 % of known reserves and resources in the U. S. The currently known Li resources in the U.S. exceed those currently known in Bolivia (23 Mt) and Argentina (22 Mt; USGS, 2024), and sets a strong basis for future domestic lithium production.
Thirteen of 17 projects in exploration stages do not yet have resource data available, suggesting that the resources in Fig. 5 will grow. The 32 deposits between exploration and study stage indicate the rapid expansion of activity around Li in recent years. Exploration is dominated by salar (9) and oil field brine (5) projects, but the only three deposits in exploration stage that have published resources are the three sedimentary deposits. The variation in stage at which projects publish resource numbers may point to differences in reporting and technology advancement timelines lines between rock and brine exploration studies. Study stage (67 % of domestic resources) includes all deposit types, however, sedimentary deposits make up 53 % of total resources in the study stage. The remainder of resources in the study stage are 20 % from oil field brines, 13 % from salar brines and 7 % from pegmatites and geothermal brines. Resources and the number of projects drop off into permitting stage with one sedimentary and one oil field brine project. Mine permitting in the U.S. is a multi-year process (SNL Metals & Mining, 2015), followed by several years for construction. It is not possible to predict which, if any, of these deposits will go into production. Economics, permitting, and other factors such as those illustrated in Fig. 4 will influence exploration and production decisions, thereby determining the resources, reserves, and the actual supply of lithium in the short, medium, and long term. Andrade et al. (2024) present an essential analysis of factors that influence lead times, with a median lead time of ~12 years globally for lithum deposits, a range of 4 to 27 years, and both North American and European projects having longer times than other regions (studied projects between 2004 and 2022). They find both external factors (e.g. country, market and lithium price) and internal factors (e.g. deposit type, grade, company size and expenditure) to influence project progression differently at different stages, an understanding that enables vital constraints on future production of lithium both in the U.S. and globally.
This review, has shown project timelines and outcomes will be driven by environmental and social feedback, and changes in state policies and regulatory risks. Both solid and solution deposit types and their associated production methods will be affected. Clear examples of the regulatory influences are the recently abandoned brine project at Great Salt Lake (UT) which comprises 67 % of salar brine resources, and the pegmatite projects in Maine accounting for 32 % of pegmatite resources. These projects highlight the importance of understanding environmental and social impacts and community and policy engagement early on. The geological setting of lithium deposits means many are in a locations of fragile ecosystems, water scarcity and tribal lands. A consolidated and systematic effort to understand these ecosystems and communities in geographical areas of interest could reduce risk at an early stage by re-directing exploration to areas with low environmental and social impacts. In turn this may reduce the economic and supply chain risks of projects failing at a late stage. This review provides a foundational assessment of the lithium landscape in the U.S. Detailed research especially into the environmental, social and economics of lithium production and the timing of progress across the supply chain is required to enable responsible production. 12345. All percentages given are proportions of the total known domestic resources plus reserves. From left to right the distributions show: solid vs solution; deposit type; project stage within each deposit type (Table 6); number of projects with known resources (including reserves where available) compared to the total number of projects in each project stage; defined resources (including reserves where available) by project stage. Branch thickness corresponds to relative percentages within each segment, except for the fourth segment showing number of projects in each stage. Summary built from combined (inferred, indicated and measured resources and proven and probable reserves), converted to contained lithium to allow comparability across deposit/production types. resources are each only 3 % of the total domestic resource. One pegmatite project is in development for proposed open pit mining in North Carolina. Geothermal brines are being explored as a potential lithium resource in the Salton Sea in California and constitute 11 % of domestic resources. Two of these projects are in final permitting stages. Lithium recovery is being investigated from oil field brines in Arkansas, Texas, and Utah and currently comprises 6 % of the domestic resource, for which one deposit is in permitting stage in Arkansas. The known resources and reserves of Li in the US are potentially sufficient to meet a significant proportion of domestic demand, depending on the rate of demand increase and whether these deposits are developed.
Lithium extraction within the U.S. and in foreign jurisdictions has seen much criticism on environmental and social issues, in particular surrounding water quality and quantity, and Indigenous rights over traditional and ancestral territories. Lithium remains at the core of postcolonial systems of extraction that, consciously or not, can reproduce injustices and inequalities that have marked communities' relationships to mining for centuries. The over-burdening of Indigenous communities with disproportionate impacts of lithium mining will constitute a significant obstacle for achieving a just transition.
Increased momentum for a secure domestic supply through investment and fast track programs is framed by the need for domestic policies to prioritize production types and projects with low environmental impact that may lead to greater social acceptance. Research and development on direct lithium extraction is needed to enable production using less water than evaporative concentration and potentially resulting in minimal landscape disruption relative to open pit mining of lithium clays and pegmatites. Despite the geological endowment and production potential of lithium in the U.S., domestic production is unlikely to ramp up quickly enough to supply the whole American manufacturing base immediately. Thus, policymakers will need to maintain friendshoring strategies to secure supplies from other countries, including Chile, Argentina, and Australia.
The potential impacts of lithium production emphasize the importance of establishing responsible lithium supply chains. Both environmental and social impacts must be considered from the initial stages of exploration and permitting through to mine construction, production, refining, and end-of-life recycling or disposal of battery materials. Building on the review of U.S. lithium projects, this contribution shows how the conceptual landscape of lithium development is influenced by deposit type, production method, and complex domestic and global factors.