Novel Method for Addressing Environmental Challenges in Coal Mining

Researchers from Shanxi University in China and The University of Western Australia have developed a novel method for addressing the environmental challenges posed by coal mining. Their study, published in Engineering, presents a comprehensive solution that integrates the treatment of coal mine goafs, utilization of coal-based solid waste, and sequestration of CO2 through mineralization. This approach aims to reduce the ecological and environmental impacts of coal mining while also contributing to the reduction of CO2 emissions.

Key Takeaways:

• The study proposes a method to utilize coal-based solid wastes, such as fly ash, carbide slag, and red mud, to create cementitious materials for filling coal mine goafs while sequestering CO2 through mineralization.
• The carbon sequestration capacities of fly ash, carbide slag, and red mud were found to be 3.8, 359.3, and 5.7 kg/t, respectively.
• The mechanical properties of the filling material, particularly its compressive strength, were significantly improved through CO2 mineralization, reaching a maximum compressive strength of 14.9 MPa.
• The utilization of these wastes to create composite solid waste (fly ash-carbide slag-red mud) mineralized with CO2 could reduce carbon emissions by 1.23 Mt annually in China.
• The study estimates that the total underground space volume of coal mine goafs from 2016 to 2030 in the Yellow River Basin in China could sequester 0.18 Gt of CO2.
• The findings highlight the potential for integrating waste management and carbon sequestration in the coal industry, offering a sustainable approach towards achieving carbon neutrality goals.

Statistics:

• The annual production of fly ash, carbide slag, and red mud in China is approximately 899, 30, and 107 Mt, respectively.
• The CO2-major mineralization reaction can mineralize CO2 at rates of 1%, 2%, and 4% for FA, CS, and RM, respectively.
• The total underground space volume of coal mine goafs from 2016 to 2030 in the Yellow River Basin in China is estimated at 8.16 Gm3.
• The potential carbon emission reduction through this technology could reach 16.46 Mt, considering the historical stockpiles of these solid wastes.

Sources:

• Wang et al. (2025) "CO2 Mineralized Full Solid Waste Cementitious Material for Coal Mine Goaf Filling and Carbon Sequestration Potential Assessment." Engineering, Volume 2025, Issue 2, https://doi.org/10.1016/j.eng.2025.02.017.
• ScienceDirect (2025) "Engineering Journal." https://www.sciencedirect.com/journal/engineering.