Long-Term Solutions to Acid Producing Coal Mine Spoils Using Industrial Wastes

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

1236403 (Liang). Around the world, mining exposes fresh mineral surfaces that have never been in contact with the atmosphere and often creates oxidation enabled pollution. Historically, the mining industry has utilized the target mineral and dumped materials deemed not useful as ?refuse piles? that often became small mountains that produce acid discharges. These discharges are commonly manifested in the Appalachian region of the USA as acid mine runoff that has become prevalent since coal mining became a major industry over 100 years ago. Not only are these acid discharges environmentally damaging to watersheds, the coal refuse piles themselves are barren lands that are virtually useless, as game, forest, or agricultural lands. Such legacy mining issues are a blight and have one of the most detrimental environmental impacts in the Appalachian region where metal compounds from the refuse piles, including ferric and ferrous iron, aluminum, and manganese (sulfate and chloride as the most common counter-ions), are continuously leached from these coal refuse piles and/or abandoned coal mines causing the acid mine drainage (AMD). The produced AMD deteriorates water quality throughout a watershed by decreasing the pH in soil pore water and river flow. AMD has not only been a significant environmental problem in the coal production Appalachian regions in the US, but also will certainly become a significant and harmful environmental problem in the coal production regions around the world as coal is used as one of the most inexpensive forms of energy to power the ever increasing world population. Therefore, it is necessary to have an economically sound and technically effective long-lasting approach to deal with the AMD problem. This research project addresses this need using an industrial ecology based approach to mix the surface materials of these refuse piles with brown mud, a residual of Bauxite processing from aluminum manufacturing. In this project, an objective is to determine the longevity and permanence of this industrial ecology-based remediation approach, as many previous remediation efforts fail over time due to eventual loss of alkaline material to neutralize the ever ongoing acid production via iron oxidation. Using such a combined approach to investigate the long-term effectiveness of the new industrial ecology-based remediation approach is critically important because this new technology has the potential to be installed at a mass scale with costs that may be minimal in comparison to the widespread installation of active treatment systems. Therefore, at the watershed scale, this type of technology may lead to a paradigm shift in AMD remediation strategy.