POTENTIAL FOR CRITICAL MINERAL RECOVERY FROM UNCONVENTIONAL SOURCES: TAILINGS FROM THE RED DOG MINE IN NORTHWEST ALASKA, USA

Critical elements (e.g., Co, Ga, Ge, In, Te, V) are crucial for green energy technologies and energy storage aiming to net-zero carbon emissions by 2050. The goal of our project is to investigate new approaches and develop interdisciplinary workflows for responsible supply of these commodities. Mine wastes are a promising unconventional source of critical minerals, and we discuss the broader economic context of tailings reprocessing. One essential consideration is that the feasibility of critical mineral recovery must be assessed differently than for new deposits.

Here we present the preliminary results of a geochemical and metallurgical assessment of the critical mineral recovery potential at the Red Dog Mine, located in the DeLong Mountains, northwestern Alaska. Red Dog represents one of the world’s largest Zn producers, generating 607,000 tonnes of Zn contained in concentrate in 2021. The Red Dog deposit is a black shale-hosted, sedimentary exhalative Zn-Pb deposit (SEDEX) deposit. The Zn grades of the deposit and the Zn recovery rates have changed over the life of the mine, leading to heterogeneity in Zn concentrations and companion metals in the tailings storage facility. In addition to preliminary geometallurgical results, we discuss how spatial and temporal heterogeneity of tailings as well as the embodied value from prior processing require non-traditional approaches to assess critical mineral potential.