DOMESTIC SOURCES OF BARITE AND FLUORSPAR: WHAT MAKES INDUSTRIAL CRITICAL MINERALS DIFFERENT?

Criteria for inclusion of a mineral commodity on the U.S. critical minerals list include (1) necessity for economic and national security, (2) supply chain vulnerability, and (3) essential domestic manufacturing function. Both barite and fluorspar are considered critical minerals despite global and domestic abundance of mineral resources. The United States relies on imports for more than 75% of barite and 100% of fluorspar supply. The United States is the world’s leading consumer of barite, a low-cost bulk commodity used primarily for its weight in drilling muds for the oil and gas industry. Domestic barite mine production peaked in the early 1980s with more than 30 active deposits in 9 states. Three companies mined barite in Nevada in 2022. Key considerations for mining barite deposits are their conduciveness to simple beneficiation methods and proximity to rail and ocean transportation networks. Purity requirements are the key differentiator for using fluorspar as a source of fluorine in chemical applications. The last domestic fluorspar mine closed in 1996, but minimal quantities of metallurgical-grade fluorspar continue to be recovered annually as a byproduct of limestone quarrying in Illinois. Fluorosilicic acid, a byproduct of phosphate rock processing, supplements fluorspar as a domestic source of fluorine. Continued market growth for downstream fluorochemicals is driven by the use of refrigerants with lower global-warming potential as well as use in lithium-ion batteries, fuel cells, and solar photovoltaics. Most U.S. barite and fluorspar mines are intermittently active, depending on demand.

The Earth MRI project identified 52 focus areas for domestic sources of barite and 37 focus areas for fluorspar based on areas with past production, identified resources, or permissive geology for deposit types that host these commodities. In addition to bedded barite deposits (such as the Nevada barite belt), byproduct barite could be recovered by flotation from some zinc-rich volcanogenic massive sulfide (VMS) deposits. Mississippi Valley Type (MVT) districts commonly host both barite and fluorspar deposits (for example, Illinois-Kentucky fluorspar district). Efforts to decrease import reliance would need to address economic factors such as improved processing and transportation costs.