OF-24-11 Reconnaissance Investigation of Critical Minerals in Historic Mine-Related Effluent, Colorado

The work presented in this report is supported by the U.S. Geological Survey under the Earth Mapping Resources Initiative (EarthMRI). This report covers the potential critical mineral endowment of mine waste in Colorado, specifically from select acid mine drainage (AMD) sites, through field sampling and laboratory analysis. Please see our related publication, OF-24-10 Reconnaissance investigation of critical minerals in mine-related waste for additional information on this topic. Digital ZIP download. OF-24-11D.

From the introduction:

Colorado contains an abundance of historic mine-related waste materials, some of which may contain elevated concentrations of critical minerals and other metals. Many of these sites are currently being remediated by several entities including the U.S. Environmental Protection Agency (EPA), Colorado Department of Public Health and Environment (CDPHE), and/or other entities. Metal-laden water flows continuously from some of these acid mine drainage (AMD) sites where it is collected, treated, and discharged to local streams and rivers, depending on its potential impact to human health and the environment. In Colorado, the typical driver for many of these AMD remediation efforts is elevated metals (such as cadmium, copper, and zinc) in water discharging to Colorado waterways that can impact downstream users and aquatic ecology. Many of these historic mining sites are associated with mineral deposits that may contain critical minerals, or historically produced a few of these minerals, and therefore, the water effluent from these sites may contain these materials as well. Several of the critical minerals typically occur in trace amounts in ore deposits and are not always included in AMD monitoring programs.

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.