AccScience Publishing / AJWEP / Online First / DOI: 10.36922/AJWEP025200154
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ORIGINAL RESEARCH ARTICLE

Utilization of coal gangue and fly ash for sustainable mine backfill: Rheology and stability optimization of slurry

Jianjun Hou1,2 ,  Zhigang Li1 ,  Jian Wang2 ,  Zhiling Ren2 ,  Yang Yang2 ,  Zhongquan Liu1 ,  Linqiang Mao1*
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1 Department of Mining Engineering, Team 113 of Coalfield Geology Bureau of Guizhou Province, Guiyang, Guizhou, China
2 Department of Environment Engineering, School of Environment Science and Technology, Changzhou University, Changzhou, Jiangsu, China
AJWEP, 025200154 https://doi.org/10.36922/AJWEP025200154
Received: 14 May 2025 | Revised: 8 July 2025 | Accepted: 11 July 2025 | Published online: 31 July 2025
© 2025 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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Abstract

By systematically optimizing particle size distribution and solid mass concentration, this study develops high-performance coal gangue-fly ash backfill slurry with enhanced rheological properties and stability. X-ray diffraction and performance analyses confirmed that the synergistic combination of crystalline aluminosilicates in coal gangue and amorphous aluminosilicate glass in fly ash significantly contributes to the formation of a cohesive C-(A)-S-H gel network under alkaline conditions, thereby improving the mechanical integrity and stability of the backfill matrix. Slurries with solid mass concentrations between 68% and 76% displayed typical Bingham plastic behavior, with increasing concentration significantly improving both plastic viscosity and yield stress, thus enhancing resistance to bleeding and segregation. Particle size analysis indicated that a distribution modulus of ik = 0.91 effectively minimized bleeding while maintaining high flowability, improving slurry homogeneity and pumpability. An optimal formulation was identified at a 72% solid mass concentration with optimized particle size distribution, providing a balance between workability and stability. These results confirm the potential of coal gangue-fly ash systems as sustainable and cost-effective backfill materials and offer practical guidance for mix design in large-scale underground mining applications. Furthermore, this approach promotes the green reuse of bulk industrial by-products, advancing the sustainable development of solid waste while supporting safe and environmentally responsible mine reclamation.

Keywords
Backfilling slurry
Coal gangue
Fly ash
Flowability
Stability
Funding
This research was funded by the Guizhou Provincial Energy Bureau Science and Technology Project (Project name: Technical Research and Development of Coal Gangue Underground Backfill Mining Technology and Its Pilot Application by Guizhou Zhaping Coal Industry Co., Ltd; Grant number: 2023–68).
Conflict of interest
The authors declare no competing interests.
References
  1. Liu R, Wang S. Research progress on the comprehensive utilization of coal gangue. Int J Coal Prep Util. 2025;45:1-15. doi: 10.1080/19392699.2025.2467736

 

  1. Zheng Q, Zhou Y, Liu X, Liu M, Liao L, Lv G. Environmental hazards and comprehensive utilization of solid waste coal gangue. Prog Nat Sci Mater Int. 2024;34:223-239. doi: 10.1016/j.pnsc.2024.02.012

 

  1. Tao1 Z, Xinjuan1 W, Cheng X, Qiuge J, Siyuan SU. Current situation and progress of coal gangue resource utilization. Coal Sci Technolo. 2024;52:380-390. doi: 10.12438/cst.2023-1917

 

  1. Sun Y, Bai B, Yang X, et al. Coal gangue utilization: Applications, challenges, and sustainable development strategies. Energies. 2025;18:444. doi: 10.3390/en18020444

 

  1. Montgomery A, Kasaniya M, Zhao P, Thomas M, Peterson K. The dam that fly ash built. J Microsc Oxford. 2024;294:117-127. doi: 10.1111/jmi.13248

 

  1. Alrawashdeh AA, Zamorano M, Martín-Morales M, Alshaaer M, Wastiels J. The role of the gasification forest fly ash (GFF) in geopolymerization. Constr Build Mater. 2025;468:140470. doi: 10.1016/j.conbuildmat.2025.140470

 

  1. Alqawasmeh HM. Enhancing the sustainability of geotechnical engineering with utilization of fly Ash. Discover Mater. 2025;5:11. doi: 10.1007/s43939-025-00183-0

 

  1. He X, Li W, Yang J, et al. Multi-solid waste collaborative production of clinker-free cemented iron tailings backfill material with ultra-low binder-tailing ratio. Constr Build Mater. 2023;367:130271. doi: 10.1016/j.conbuildmat.2022.130271

 

  1. Zhao Z, Ma L, Ngo I. et al. Experimental investigation on hydrophobic alteration of mining solid waste backfill material. Minerals. 2024;14:580. doi: 10.3390/min14060580

 

  1. Wang M, Su J, Qin H, et al. Research on active advanced support technology of backfilling and mining face. Rock Mech Rock Eng. 2024;57:7623-7642. doi: 10.1007/s00603-024-03808-7

 

  1. Yadav AK, Mishra S, Mishra DP. A detailed review study on utilization of mine and industrial wastes for backfill strengthening. Arab J Geosci. 2024;17:121. doi: 10.1007/s12517-024-11917-4

 

  1. Deng X, Li Y, Wang F, et al. Experimental study on the mechanical properties and consolidation mechanism of microbial grouted backfill. Int J Min Sci Technol. 2022;32:271-282. doi: 10.1016/j.ijmst.2022.01.010

 

  1. Chen Q, Wu A. Research progress of phosphogypsum-based backfill technology. Chinese J Eng. 2025;47:195-214. doi: 10.13374/j.issn2095-9389.2024.08.06.002

 

  1. Luo S, Gao S, Yang L, João CG, Wang D. Enhancing coal gangue aggregates with fly ash-cement slurry: Synergistic effects of CO2 mineralization on physical and mechanical properties. Constr Build Mater. 2024;440:137389. doi: 10.1016/j.conbuildmat.2024.137389

 

  1. Guo L, Zhou M, Wang X, Li C, Jia H. Preparation of coal gangue-slag-fly ash geopolymer grouting materials. Constr Build Mater. 2022;328:126997. doi: 10.1016/j.conbuildmat.2022.126997

 

  1. Deng X, Jiao Y, Li S, et al. Evaluation of the migration and environmental effects of metal elements within cementitious gangue-fly ash backfill in underground coal mines. Int J Min Sci Technol. 2024;34:1551-1562. doi: 10.1016/j.ijmst.2024.11.002

 

  1. Gao S, Zhao S, Yang L et al. Synergistic effects of fly ash-cement slurry and CO2 mineralization on coal gangue aggregate and its concrete properties. Constr Build Mater. 2025;465:140225. doi: 10.1016/j.conbuildmat.2025.140225

 

  1. Zhang X, Zhu S, Yang T, Wang Y, Li J, Li K. The influence of coal gangue dosage and concentration on the properties and hydration mechanism of fly ash-based cemented filling materials. J Clean Prod. 2025;492:144903. doi: 10.1016/j.jclepro.2025.144903

 

  1. Wang Y, Li H, Huang G, Liang Q, Cheng Q. Rheological properties of gangue-filled slurry based on L-pipe experiments. Can Metall Quart. 2025;64:1437-1448. doi: 10.1080/00084433.2024.2395638

 

  1. Liu B, Zhang Y, Yang S. Influence of coal gangue-aeolian sand aggregate gradation on rheological properties and pipeline transportation characteristics of filling slurry. Sci Rep. 2025;15:789. doi: 10.1038/s41598-024-84955-3

 

  1. Wenbin X, Wei C, Yalun Z, Bocen C. Research on rheological characteristics of gangue-fly ash slurry in deep filling mining. Coal Sci Technol. 2023;51:85-93. doi: 10.13199/j.cnki.cst.2021-0444

 

  1. Rawat A, Singh SN, Seshadri V. Computational methodology for determination of head loss in both laminar and turbulent regimes for the flow of high concentration coal ash slurries through pipeline. Particul Sci Technol. 2016;34:289-300. doi: 10.1080/02726351.2015.1075637

 

  1. Jung SJ, Biswas K. Review of current high density paste fill and its technology. Miner Resour Eng. 2002;11:165-182. doi: 10.1142/S0950609802000926

 

  1. Ellis DV. A review of some environmental issues affecting marine mining. Mar Georesour Geotec. 2001;19:51-63. doi: 10.1080/10641190109353804

 

  1. Lang L, Lei X, Meng-Bo Z, Shi-Shan R, Wei-Ji S, Cheng-Cheng S. Properties of ultrahigh fluidity modified magnesium slag-based filling materials. Chinese J Eng. 2023;45:1324-1334. doi: 10.13374/j.issn2095-9389.2022.06.06.001

 

  1. Wang Z, Wang Z, Zhao W. Microscopic pore and filling performance of coal gangue cementitious paste. J Wuhan Univ Technol. 2018;33:427-430. doi: 10.1007/s11595-018-1840-9

 

  1. Zheng BK, Yao W, Huang TL, Zhang LY, Yin XY. Transportable performance of modified unclassed tailings filling slurry based on loop test. Chinese J Nonferr Metal. 2021;31:520-529. doi: 10.11817/j.ysxb.1004.0609.2021-35941

 

  1. Li M, Yan P, Han J, Guo L. Which is an appropriate quadratic rheological model of fresh paste, the modified Bingham model or the parabolic model? Processes. 2022;10:2603. doi: 10.3390/pr10122603

 

  1. Wang Y, Wang LQ, Cao C, Liu W. Characterization of filling slurry yield stress based on a mini-slump cone test. Chinese J Eng. 2023;45:1316-1323. doi: 10.13374/j.issn2095-9389.2022.11.04.003

 

  1. Xiao J, Wang S, Ye S, Wang J, Wen J, Tu J. Experimental investigation on pre-heating technology of coal water slurry with different concentration in shell-and-tube heat exchangers with ladder-type fold baffles. Int J Heat Mass Tran. 2019;132:1116-1125. doi: 10.1016/j.ijheatmasstransfer.2018.12.082

 

  1. Lei Z, Tianqi S, Wenzhe G, et al. Experimental research on transport⁃resistance characteristics of gangue slurry and its flow trend in goaf. J China Coal Soc. 2022;47:39-48. doi: 10.13225/j.cnki.jccs.2021.1298

 

  1. Liu P, Liu Z, Lu Z, Guo Y, Qiu Y. Study on preparation and influencing factors of coal gangue fill slurry material. Case Stud Constr Mater. 2024;21:e03986. doi: 10.1016/j.cscm.2024.e03986

 

  1. Zhang X, Russell AR, Dong X. Liquefaction responses of fibre reinforced sand in shaking table tests with a laminated shear stack. Soil Dyn Earthq Eng. 2022;162:107466. doi: 10.1016/j.soildyn.2022.107466

 

  1. Baldermann A, Preissegger V, Dietzel M. Solubility of C-A-S-H phases with high degree of heavy metal ion substitution. Constr Build Mater. 2022;327:126926. doi: 10.1016/j.conbuildmat.2022.126926

 

  1. Liu CL, Chen ZF, Zhu Y, Yu JG. Fundamental study of leaching kinetics and mechanism of spodumene assisted by mechanical activation. Miner Eng. 2024;218:108936. doi: 10.1016/j.mineng.2024.108936

 

  1. Golik VI, Klyuev RV, Martyushev NV, Zyukin DA, Karlina AI. Technology for nonwaste recovery of tailings of the mizur mining and processing plant. Metallurgist. 2023;66:1476–1480. doi: 10.1007/s11015-023-01462-y
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Asian Journal of Water, Environment and Pollution, Electronic ISSN: 1875-8568 Print ISSN: 0972-9860, Published by AccScience Publishing
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