Hydraulic Behavior and Inrush Mechanisms in Coal Mining Systems

Coal mining inevitably alters subsurface hydraulic regimes through excavation-induced fracturing, stress redistribution and fluid pressure perturbations. The advance of longwall or room-and-pillar workings creates a water-conducting fracture zone above the extraction face, establishing pathways for groundwater inflow. Coupled hydro-mechanical processes govern the evolution of pore structure and connectivity; stress perturbations may open or close fractures, while seepage forces can erode granular material and enlarge conduits. Flow regimes commonly deviate from classical Darcy behaviour, transitioning to non-Darcy or even turbulent flow under high hydraulic gradients. Karst features and collapse pillars further complicate the picture by introducing highly heterogeneous pathways that can activate rapidly when intersected by mining operations. The resulting inrush events pose severe safety and environmental risks, driving the development of integrated monitoring, numerical modelling and design strategies. Recent advances combine novel geophysical imaging, laboratory-scale experiments on granular and fractured media, and field-scale numerical simulations to elucidate the critical controls on water inrush occurrence and to inform the dimensioning of protective barriers or grouting schemes. The global significance of these studies spans deep coalfields in China, Australia and Eastern Europe, where water management underpins both operational safety and sustainable resource recovery.

Research from Nature Portfolio

A recent investigation of mining–aquifer interactions in complex overburden strata applied transient electromagnetic and high-density three-dimensional electrical methods to delineate water-rich abnormal zones above a longwall face. Two discrete high-risk areas were identified at 30–60 m and 45–60 m beneath the roof, with mapped extents exceeding 2 900 m2. Empirical, theoretical and field-monitoring estimates of the mining-induced fracture zone height converged on a maximum of 42.6 m, enabling the calculation of a minimum water-barrier pillar width. The study demonstrated that targeted adjustment of pillar dimensions can substantially reduce inrush risk and provided a transferable methodology for similar coal mines worldwide.

Hydraulic Behavior and Inrush Mechanisms in Coal Mining Systems publication trend

The graph below shows the total number of articles in hydraulic behavior and inrush mechanisms in coal mining systems across all publications each year (not limited to Nature Index journals).

Technical terms

Water inrush: Sudden and rapid inflow of groundwater into mine workings when hydraulic connections are established between aquifers and excavations.

Water-conducting fracture zone: A network of mining-induced fractures above an excavation face that permits vertical and lateral fluid movement.

Non-Darcy flow: Flow regime in porous or fractured media where inertial effects lead to deviations from linear Darcy’s law, typically described by Forchheimer or turbulent flow models.

Karst collapse pillar: A geological structure composed of fragmented carbonate rocks and voids that can form high-permeability pathways when intersected by mining.

Stress-seepage coupling: Interaction between mechanical stress fields and fluid flow, whereby changes in stress alter permeability and vice versa.

References

1. Study of the mining and aquifer interactions in complex geological conditions and its management. Scientific Reports (2023).
2. A state-of-the-art review on rock seepage mechanism of water inrush disaster in coal mines. International Journal of Coal Science & Technology (2022).
3. Evolution Mechanism of Water‐Conducting Channel of Collapse Column in Karst Mining Area of Southwest China. Geofluids (2021).