Phytostabilization of coalmine overburden waste rock dump slopes: current status, challenges, and perspectives

Coal production is accompanied by the generation of a massive quantity of coal overburden (OB), which is stacked on the adjacent ground in the form of external dumps. The major problems associated with the coal OB dumps are groundwater and nearby soil contamination due to heavy metals, land degradation, and biodiversity loss. The OB material stacking results in the formation of massive dumps that are vulnerable to slope failure, endangering production safety, and risking human lives. This paper provides an in-depth analysis of published literature through a systematic bibliometric analysis to ascertain the trend topics regarding the generation and management of OB across the world. The traditional reclamation and slope stabilization techniques, the benefits and limitations of various biological remediation processes, and the advantage of vegetation over others as a more sustainable approach for OB management have been summarized. The major challenges associated with vegetation and future required research to implement it in real field conditions are identified and emphasized. During vegetation, the species selection for land reclamation of the degraded land, slope stabilization, extraction of heavy metals, and eco-restoration are also critically reviewed. Furthermore, the mechanism of dump slope stability enhancement, and the methods to estimate the root cohesion that governs the factor of safety in the vegetation process are discussed in detail. The grasses and the trees aided with the organic amendments have proved to be effective in erosion control and slope stabilization of dumps, respectively, along with enhancing the aesthetics. It was found that the species selection based on root morphology, the intended use, and the point of application (in the case of slopes) governs the efficacy of the reclamation programs, which requires further research.