Potential Valorisation of South African Coal Waste as a Sustainable Waste Management Approach: Insights from Environmental Geochemical Assessments
摘要
Environmental Geochemical Assessments (EGAs) and waste classifications studies are essential for identifying environmental risks and informing appropriate disposal strategies for mining waste. However, their traditional application often excludes assessments of resource recovery potential. This study presents an EGA conducted on coal discard from a historical coal mine in Limpopo, South Africa, focusing on assessing acid generation potential, and leaching behavior. To explore the potential for waste valorisation, the study integrates a literature-based case study involving dense medium separation, drawing from the work of Do Amaral Filho et al. and Dos Santos et al. These studies demonstrate how beneficiated coal discard fractions, particularly intermediate-density material (2.2–2.7 g/cm3), can be repurposed for applications such as aggregate substitution in concrete paving blocks. Risk-based assessments from these published studies highlight the feasibility of such reuse options while reducing acid mine drainage risk and waste volumes. Additionally, these risk-based assessments informed projections on how similar beneficiated fractions of the Limpopo coal discard might behave, using the site-specific EGA data as a foundation. Drawing from these insights, we propose a six-step integrated assessment framework that links geochemical characterization, predictive simulation, valorisation screening, post-beneficiation risk re-assessment, techno-economic evaluation, and decision-making in material management pathway. This framework supports science-based waste reclassification under the South Africa’s Waste Exclusion Regulations (GN R. 715 of 2018) and can be adapted to other mining commodities and lifecycle stages. This contributes to a shift in waste governance from containment to reuse, aligning coal waste practices with circular economic objectives.