Background Abandoned mine drainage, also known as acidic mine drainage (AMD), represents a major pollution source in mining areas while also serving as an important carrier of strategic critical metals and underground space utilization. In China, water pollution stemming from coal mining is more severe in the south than in the north. This spatial pattern is jointly shaped by climatic conditions, geological settings, and mining history.
Advances From the perspective of the environmental geochemical frontier, this study presents a systematic review of AMD formation and evolution mechanisms, as well as technologies for water pollution prevention and control, resource recovery, and collaborative energy utilization. The water quality of an abandoned mine undergoes a distinct three-stage evolutionary process: (1) heavy metal concentration peaking in the initial stage, predominantly governed by inorganic water-rock interactions; (2) microbially driven self-purification in the medium term; and (3) dynamic equilibrium after mixing with the regional groundwater system in the long term. Analysis of the kinetic process of pyrite oxidation indicates that the initiation of initial acidification by neutrophilic microbes plays a key role in controlling the AMD release rate. Furthermore, the source-sink evolution pattern of contaminants in complex karst-water media is elucidated, revealing that the adsorption and desorption of heavy metals are subjected to the nonlinear control of secondary minerals’ precipitation and aging induced by the buffering effect of carbonate rocks.
Prospects Given the evolutionary characteristics of mine water quality in different stages after the mine abandonment, it is necessary to select technologies for valuable resource recovery by deeply coupling the evolutionary stages. Specifically, in the initial stage, an electrochemically activated limestone system should be employed for targeted metal recovery; in the medium term, valuable elements in element-enriched precipitated slags can be converted using sulfuric acid leaching, and in the long term, a class-based treatment and regulation system should be established based on distinct water quality characteristics. The results of this study will provide a scientifically robust basis and a technical pathway for developing a new paradigm of water pollution treatment and valuable element reutilization for abandoned mines.
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