Lithium is a light-weight metal that has historically been used to manufacture ceramics and glasses, greases, and nuclear weapons. Lithium’s combination of high storage capacity and low weight makes it ideal for use in batteries, particularly in electric cars, as well as other electronics such as cell phones and computers. Lithium-ion batteries are also used for energy storage on electric grids.


Lithium is mined in two primary ways: from salty brines and from hard rock ore. Most of the lithium mined today comes from brine mining in the so-called lithium triangle in South America: Bolivia, Chile, and Argentina. Brine mining has come under fire for using massive amounts of water in extremely arid regions, degrading ecosystems, forcibly removing local populations, and otherwise disrupting Indigenous and other localized land-based lifeways. Still, extracting lithium from brine is generally considered much more economically attractive and environmentally friendly than mining from hard rock, because of the extensive processing required in hard rock lithium mining. The Kings Mountain in North Carolina was the world’s main producer of lithium from hard rock until it closed in 1998, as cheaper brine mining in South America came online. Today, Australia is the world’s main producer of lithium from hard rock. 

Lithium in the Black Hills exists in spodumene, a hard silicate mineral found in pegmatite rocks. Lithium mining in the Black Hills would look closest to current operations in Western Australia, like Talison Lithium’s Greenbushes project. Two companies have staked claims and are pursuing lithium exploration in the southern Hills near Custer and adjacent to the Black Elk Wilderness Area: United Lithium and IRIS Metals.

The supply chains required to produce lithium-ion batteries are complex, requiring sourcing of up to 20 different materials from different locations around the world. In 2018, less than 3% of the total demand of electric vehicle batteries was produced outside of China, Japan, and Korea, and in 2021, 95% of Australia’s raw spodumene (hard rock) material was exported to China. Thus, though the US government has listed lithium as a mineral “critical to US national security and the economy,” most of the lithium-ion battery supply chain still lies outside the US. Brine mining has proven to be more cost effective than hard rock mining unless complex, chemically- and energy-intensive processing can occur next to the extraction site.

Lithium mined from hard rock requires intensive chemical treatment before it can be used to produce batteries. Ore is first excavated using open-pit or underground mining methods, using drill rigs and explosives. The ore must be crushed and milled to remove other materials like quartz, feldspar, and mica. Once a concentrate is produced, it must be heated to a very high temperature before further processing is possible. The concentrate is then subjected to intense leaching, usually with the use of sulfuric acid, before sodium carbonate is added and the resulting mixture is once again heated, filtered, and dried. Alternatives to the high temperature and sulfuric acid leaching process have been explored, some (like using hydrochloric or hydrofluoric acid) much riskier from a health and safety perspective. A 2013 study estimated that each ton of lithium carbonate produced from spodumene requires 1.34 tons of spodumene, 0.48 tons of sulfuric acid, 0.52 tons of soda ash, 24 tons of water, and significant amounts of energy to power the process.

Mining companies are quick to associate with the ‘responsible,’ green, low-carbon energy of the future. However, this entire hard rock lithium extraction process contributes to an increase in greenhouse gasses and carbon dioxide by clearcutting trees and requiring massive amounts of energy for processing. The sulfuric acid method described is associated with the emission of acid gas. Like any version of hard rock mining, toxic chemicals are used during processing, and potentially dangerous amounts of lithium can be found in ponds and tailings. When spodumene is crushed, a silica-rich dust results, which is a health and safety concern. 

In the fervor of electric vehicle enthusiasm, very little research has been conducted on the social and environmental impacts of lithium production. Many more studies have focused on the impacts of battery production and waste, rather than the localized impacts of mining. However, at a Foote Mineral processing plant near Philadelphia, wastes generated by lithium processing leaked into the groundwater and in 1992, the plant became eligible for Superfund cleanup status. At Greenbushes in Western Australia, dust clouds have contaminated rainwater tanks, and frequent explosions have produced fume emissions containing nitrous gasses and carbon monoxide. Concerns about groundwater contamination have gone unaddressed, and the processing of spodumene ore results in 600,000 tons of waste material per year. In Nevada, adverse impacts to fish have been identified 150 miles downstream from a lithium processing operation. Lithium mining from both brine and clay (proposed for Lithium Americas’ Thacker Pass project) are extremely water intensive and associated with groundwater contamination.

Lithium affects metabolism, neuronal communication, cell proliferation, and embryonic development in humans and other animals. Breathing lithium dust compounds can irritate respiratory systems and cause lung fluid buildup. Exposure to lithium carbonate can produce toxicity in the neuromuscular, cardiovascular, and gastrointestinal systems. Lithium has been used as a treatment for bipolar disorder, but studies show the window between effective dosing and toxicity to be narrow, with adverse side effects common even at therapeutic doses. Lithium also disturbs the development of invertebrates and has been linked to reduced litter sizes and offspring weights in rats. At certain concentrations in soil and water, lithium has shown to be deadly to earthworms and fish.

IRIS Metals is an Australian exploration company currently exploring for gold, nickel, and lithium in Western Australia in addition to its claims in the Black Hills. IRIS recently acquired 275 lode claims covering 5681 acres southeast of Custer (‘Custer Project’) and 250 lode claims covering 5265 acres just north of the Black Elk Wilderness Area and south of Hill City (‘Dewy Project’) from White Rock, LLC. All claims sit on Forest Service land. IRIS has hired the recently organized RLL Consulting, LLC, to assist with business development. The recently organized Lotus Minerals, LLC, is also associated with the project. IRIS states that the Dewy and Custer Project areas contain “large areas of fertile lithium-cesium-tantalum (LCT) pegmatites.” Cesium is known to be radioactive. Historic lithium bearing mines lie within both proposed project areas, including the Tin Queen and Hunter & Louise open cuts in the Dewy Project area and Custer Mountain in the Custer Project area. IRIS states that its initial exploration will consist of mapping and soil and rock chip sampling to determine targets for exploratory drilling. 

United Lithium (UL) is an exploration and development company with exploration prospects in Sweden, Finland, Canada, and now the Black Hills. UL’s Liberty Lithium Project consists of 500 lode claims over 15 square miles on Forest Service lands south of Custer. This area contains pegmatite ore bodies which were mined for lithium and beryllium for military purposes during World War II. Beryllium is included in the Environmental Protection Agency’s drinking water regulations as a toxic contaminant and is known to be dangerous to human and environmental health. UL plans to proceed by conducting geological mapping and rock chip sampling.

Neither IRIS or UL have shared details regarding their mining plans, but if hard rock mining of spodumene-bearing pegmatites elsewhere is any indication, lithium mining in the Black Hills would be energy-intensive, involve toxic chemicals and significant amounts of water, and pose threats to water resources, human health, and environmental wellbeing. The likelihood of a cost-effective operation resulting without the development of intensive, toxic processing facilities is dubious.

Currently, lithium-ion battery recycling is almost non-existent worldwide as mining companies scramble for a piece of the lithium profit pie. While divesting from fossil fuels is urgently needed, if such an adjustment is not accompanied by a serious disruption to extractive industries that are willing to contaminate water, destroy ecosystems, and violate Indigenous sovereignty all to turn a profit for the world’s wealthiest, the imbalance and destruction of our status quo energy systems will continue.

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