Industry paper

Recovery of rare earth elements from acid mine drainage using geotextile tubes containment and dewatering technology

Authors: Tom Stephens

Rare earth elements (REE) are critical to the global economy because of their use in cell phones, computers, and by the airline and aerospace industry. Areas to mine are limited and their recovery is becoming extremely expensive. In the Appalachian region of the US there is a huge and continuing problem of dealing with acid mine drainage (AMD) from abandoned coal mines. The damaging impact of this waste stream on the environment is well documented. Standard treatment of AMD involves the introduction of alkaline chemistry to precipitate metals and other solids. However, this treatment creates millions of tons of high water content sludge that is difficult and expensive to manage. A major university, in conjunction with their state Department of Environmental Quality, has conducted a multi-year pilot study using geotextile tubes to contain and dewater this AMD high water content slurry to the state that REE can be recovered economically. This paper will present the methodology and phases of the pilot project that created the proof of concept and the following scalability to the full-scale Rare Earth Element recovery project at a major abandoned mine in Appalachia. Also, this paper will present the cost of the operation and the economic feasibility offered by the application of the geotextile tube containment and dewatering technology.