C. Gorski
Colorado School of Mines,
United States
Keywords: critical minerals, rare earths, mining, innovation in mining, mineral processing, flowsheet design, process optimization
Summary:
Bear Lodge is a high-grade, rare-earth deposit that’s positioned to become one of the largest Nd-Pr oxide producers in the United States. The Department of Energy, recognizing this, has funded the site’s current research through the Critical Minerals Innovation Hub (CMI). Initial experimentation on Bear Lodge material revealed that the rock preferentially breaks along ore veins, liberating fine-grained rare earth minerals and producing a concentrate when screened. Further research indicated that scrubbing the rock's surface liberates any remnant, friable, rare-earth minerals, which deport to the concentrate stream. After scrubbing, the rocks were subject to ore sortation, which suggests that much of the deposit may be ‘rejected’ to stacked tailings after scrubbing. Results from a preliminary techno-economic assessment of the Bear Lodge flowsheet demonstrate that this process has the potential to recover 93% of the TREO, with a concentrate mass pull of 27%, and a TREO grade of 10.7% without the need for water, and at lower capital and operating expenditures than a traditional rare-earth flotation plant.