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Strength characteristics, microstructure, and carbon footprint assessment of backfill materials based on multi-source
Peng Gong1, Xiangyu Xu1, Zhanguo Ma1
1State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou, 221116, China; School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, 221116, China.
Environmental Research
|November 8, 2025
Summary
This study developed a green backfill material from coal solid waste to improve mine stability and reduce environmental impact. The optimized material meets strength requirements and significantly cuts carbon emissions, promoting sustainable mining.
Area of Science:
- Geotechnical Engineering
- Environmental Science
- Materials Science
Background:
- Stockpiling multi-source coal-based solid waste (MCSW) presents significant environmental risks.
- Utilizing MCSW as backfill in goafs enhances rock stability and controls subsidence.
- This approach promotes solid waste recycling and carbon reduction in mining operations.
Purpose of the Study:
- To develop and characterize a green backfill material using MCSW.
- To investigate its strength, microstructure, reaction mechanisms, and carbon footprint.
- To assess its suitability for goaf filling and sustainable mining.
Main Methods:
- Preparation of MCSW-based green backfill material.
- Systematic investigation of strength characteristics (UCS) and sensitivity.
- Microstructure analysis, synergistic reaction mechanism study, and Life Cycle Assessment (LCA).
Main Results:
- Coal gangue particle size impacts early strength; waste proportions and slurry concentration dictate later strength.
- Optimal ratios and 76-78% mass concentration yield >5 MPa 28d UCS.
- MCSW backfill, especially FA60, reduces carbon emissions by 43% compared to conventional materials.
Conclusions:
- MCSW-based backfill meets mechanical strength requirements for goaf filling.
- This sustainable material effectively reduces solid waste accumulation and carbon emissions.
- MCSW backfill shows strong potential for green and sustainable mining applications.
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