1.0 INTRODUCTION
The Upton Plant includes the Hydrometallurgical Plant (Hydromet Plant) and the Tailings
Storage Facility (TSF). The rare earth elements (REE) mineral pre-concentrate will be
transported by enclosed trailered truck from the Bull Hill Mine to the Hydromet Plant.
The Hydromet Plant process will use hot hydrochloric acid leaching to dissolve the REE,
followed by additional chemical processing to remove impurities, such as iron, manganese,
uranium, and thorium, and finally precipitation to produce a bulk mixed rare earth concentrate,
which represents the initial saleable product for the Bear Lodge Project. The spent hydrochloric
acid will be recycled and regenerated for re-use in the leaching process. The tailings from the
Hydromet Plant will consist of the leach residue and solids produced from acid regeneration and
will be disposed of at the TSF located within the Upton Plant Site.
It should be noted that as Rare Element Resources, Inc. (RER) continues to conduct pilot
process studies as part of upcoming definitive feasibility study planning, the REE recovery
process will be optimized. These changes in process technology will be addressed in permit
application documents to the Wyoming Department of Environmental Quality Land Quality
Division (WDEQ-LQD) and the Industrial Siting Division.
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