Digging into Kentucky’s critical mineral potential: major rock core donation from Western Kentucky Fluorspar District

The Kentucky Geological Survey (KGS) has received a generous donation of 9,930 feet of rock cores from the Western Kentucky Fluorspar District (WKFD). The collection was donated by longtime driller William “Buddy” Davidson and geologist Walt Gaylord and has now been entrusted to KGS for long-term preservation and future research. Redrilling these cores would cost approximately $241,300.

This trove of rock cores is of special importance because a portion of the cores are from the Coefield Anomaly, a section of igneous rocks located near the center of the WKFD. These rocks, which are part of the Midwest Permian Ultramafic district, are significant for their potential to host rare earth elements and other critical minerals.

There has been renewed national interest in fluorspar and other possible strategic rare earth elements and critical minerals in the WKFD. The WKFD was once a major producer of fluorspar. Fluorspar — used to make hydrofluoric acid, process steel and aluminum and manufacture refrigerants, glass and lithium-ion battery electrolytes — is considered a critical mineral due to its industrial importance and limited domestic supply. WKFD mineral deposits include lead, zinc, barite, and trace amounts of cadmium and germanium.

“The Coefield Anomaly, and the associated ultramafic intrusions, are important pieces of the geological puzzle in the Western Kentucky Fluorspar District,” says KGS geologist Tim Demko. “By obtaining and preserving these rock cores, we’re ensuring that future researchers have access to geologic information that may have otherwise been lost.”

Analysis of these cores will improve understanding of mineral associations to facilitate future research and exploration of the critical minerals in the WKFD. Additionally, alteration (reaction with water in the subsurface) of these types of igneous rocks has the potential to generate geological hydrogen, which could become an important energy resource for Kentucky in the future.