Seems much of known deposits of REEs are so complex they are difficult to mine and process.  However, I just learned of a Canadian company with possibly new technologies for processing what would otherwise be uneconomic deposits.  ...something worth watching and bearing in mind for the future.

"Ucore Rare Metals is a development-phase company focused on rare metals resources, extraction and beneficiation technologies with near term potential for production, growth and scalability. On March 3, 2015, Ucore announced the right to acquire a controlling ownership interest in the exclusive rights to IBC SuperLig® technology for rare earths and multi-metallic tailings processing applications in North America and associated world markets."

http://ucore.com/