A review of acid mine drainage: Formation mechanism, treatment technology, typical engineering cases and resource utilization

Acid mine drainage (AMD) contains high concentrations of heavy metals and sulfates with strong acidity. AMD exists in several major coal-producing countries such as China, the United States, Canada, etc., and it poses significant threaten to the environment and human health owing to it exists in nature for a long time and continues to cause harm after mining. In China, about 3.5 billion tons of AMD was produced annually and their negative effects on the ecological environment and human health in mining area cannot be ignored. Herein, the formation mechanism and environmental impact of AMD are discussed thoroughly. Additionally, the principles and applications of several AMD treatment technologies are discussed in detail and the limitations of the practical application of AMD in China are summarized. On this basis, the current status and importance of the resource utilization of AMD are further discussed. Finally, the future direction of AMD treatment is proposed. In principle, this review will provide useful implications in guiding the treatment and resource utilization of AMD.