Paper No. 24-2
Presentation Time: 1:30 PM-5:30 PM
LITHIUM PEGMATITE MINERAL RESOURCE ASSESSMENT IN THE EASTERN UNITED STATES: PROJECT OVERVIEW AND PRELIMINARY GRADE AND TONNAGE MODEL
ROSERA, Joshua1, PIANOWSKI, Laura2, HOLM-DENOMA, Christopher2, CRONKITE-RATCLIFF, Collin3, EVART, Lucas4, PHELPS, Geoff3, POLETTI, Jacob4, WINTZER, Niki4, DEANGELO, Jacob3, CROCKER, Kelsey3, WIENS, Ashton1, MORDENSKY, Stanley5, SANDERS, Margaret1, MURCHEK, Jacob1, COYAN, Joshua4, CASE, George6 and LEDERER, Graham1, (1)U.S. Geological Survey, Geology, Energy & Minerals Science Center, Reston, VA 20192, (2)U.S. Geological Survey, Geology, Geophysics, and Geochemistry Science Center, Denver Federal Center, Denver, CO 80225, (3)U.S. Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Moffett Field, CA 94025, (4)U.S. Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Spokane, WA 99201, (5)U.S. Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Portland, OR 97201, (6)U.S. Geological Survey, Alaska Science Center, 4210 University Dr, Anchorage, AK 99508
Lithium is an essential component for rechargeable batteries used in electric vehicles and energy storage applications. Forecasts project worldwide demand for lithium used in clean energy technology to increase by 40-fold by 2040 relative to 2020. Despite having identified resources of lithium, the United States relies on imports of lithium materials, and supply security has become a focal point for planning and policy decisions. A better understanding of the location and quantity of mineral resources within the United States can inform decision-makers about future supply options. The U.S. Geological Survey (USGS) has initiated a national-scale mineral resource assessment that will focus on lithium in brines, clays, and granite-related systems.
The majority of current global lithium production is from lithium-cesium-tantalum (LCT) pegmatites, a type of granite-related system. LCT pegmatite deposits have been discovered throughout the Appalachian orogen from the Central Maine Belt to the Blue Ridge and Inner Piedmont of North Carolina. These deposits are the focus for an initial three-part assessment of LCT pegmatites in the eastern United States including: 1) creating and evaluating a new global grade and tonnage model for LCT pegmatites, 2) delineating geologically permissive tracts that could contain LCT pegmatites, and 3) estimating the number of undiscovered deposits within permissive tracts. The outcome of this project will be a qualitative or quantitative estimate of how much lithium could be hosted in undiscovered LCT pegmatite deposits in the eastern United States. A quantitative estimate is contingent on constructing an appropriate grade and tonnage model to use in probabilistic simulations. Preliminary evaluation of public mineral inventory reports worldwide has documented at least 30 well-delineated deposits, including the Kings Mountain and Piedmont deposits in North Carolina, that could be appropriate for grade and tonnage modeling, with a median grade of ca. 1.1 wt% Li2O and a median tonnage of ca. 40 million metric tons.