Archived

This content is available here for research, reference, and/or recordkeeping.

Author ORCID Identifier

https://orcid.org/0009-0000-5144-0047

Date Available

5-9-2026

Year of Publication

2026

Document Type

Master's Thesis

Degree Name

Master of Science in Mining Engineering (MSMIE)

College

Engineering

Department/School/Program

Mining Engineering

Faculty

Rick Honaker

Faculty

Steven Schafrik

Abstract

Rare earth elements (REEs) - 17 elements classified as light (LREE) or heavy (HREE) - underpin modern technology. This thesis presents the development, design, and testing of a heap leach pad (HLP) to extract REEs from Western KY No.13 seam coal refuse. Testing included resource estimation, column and heap leaching, and an economic feasibility study. Drillhole analyses identified average REE concentrations in two refuse piles of 286 ppm and 290 ppm. The resource base totaled approximately 7,085 metric tons of REOs. The HLP, constructed with 2,000 metric tons of coal refuse material, was tested continuously over 308 days. Fresh lixiviant and recirculating pregnant leach solution were used to increase REE concentration and recovery. Recovery values were estimated to be 4.74% TREEs, 10.44% HREEs, and 3.01% LREEs. Column leaching evaluated effects on recovery and concentration by manipulating lixiviant selection, lixiviant concentration, irrigation rate, particle size distribution, environment temperature, material seeding, and surfactant addition. In one of eighteen tests, reduced fines, fresh lixiviant, and bioreactor tailing seeding recovered approximately 4.31% TREEs, 12.04% HREEs, and 2.53% LREEs. This thesis details the technical performance and challenges associated with operating a heap leach for critical element recovery from coal refuse.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2026.145

Archival?

Archival

Download

Share

COinS