Hydrodynamic Regulation of MICP-Treated Coal Dust: Trade-offs between Surface Erosion Resistance and Structural Homogeneity

Achieving structural homogeneity remains a key bottleneck for microbially induced carbonate precipitation (MICP) in coal-dust suppression. This study systematically investigates how injection rate and delivered reagent volume regulate MICP performance to balance wind- and rain-erosion resistance. Quantitative analysis reveals a clear trade-off arising from the interplay between fluid transport and reaction kinetics. High-rate injection triggers metastable, vaterite-rich surface clogging, reducing the wind-erosion ratio ( η wind ) to 4.2% while inducing pronounced vertical stratification. Conversely, low-rate injection promotes capillary-dominated, stable calcite bridging, thereby enhancing deep consolidation and reducing the rain-erosion ratio ( η rain ) to 8.4%. To mitigate bioclogging, we propose a graded mineralization strategy that integrates low-rate skeletal construction with high-rate surface armoring. The sequential protocol achieved a low η wind (≈ 4.0%) and reduced η rain to ≈ 9.1% compared with the high-rate case, indicating improved overall resilience under combined aeolian and rainfall stresses. The resulting functionally graded crusts offer a mechanistically grounded approach for dust suppression in complex mining environments.