OF-24-10 Reconnaissance Investigation of Critical Minerals in Mine-Related Waste, Colorado

The mineral mining industry is based on providing commodities for use in the most current technologies and products at any given time. Elements and compounds within mineral deposits that have little demand, or that cannot be extracted economically, are discarded because they have little market value or the cost to extract them outweighs the value. Modern technologies increasingly depend on some of the elements and compounds that were not mined or recovered in the past and were discarded as waste. Additionally, there has been an increase in demand for several minor, or trace, metals that typically occur in low concentrations (~<0.1%) within some ore deposits (Nassar and others, 2015) that may not form economic deposits on their own. Several commodities, including trace metals, were recently deemed “critical”, referred to as “critical minerals” by the U.S. Geological Survey (USGS) (Fortier and others, 2018; USGS, 2022) or “critical materials” by the U.S. Department of Energy (DOE, 2023), based on several factors. In Colorado, many of these critical minerals are associated with historically mined mineral deposits but were not recovered as byproducts during this time due to the lack of demand or cost to extract. Therefore, critical minerals may occur in historic waste piles located throughout the state. The primary objective of this reconnaissance study is to support the determination of potential critical mineral endowment of mine waste in Colorado. The U.S. Geological Survey (USGS), in conjunction with state geological surveys, is conducting a nationwide effort to evaluate the ability of mine waste to contribute to the U.S. critical minerals supply with the ultimate goal of estimating the potential critical mineral endowment of mine waste nationwide.