Water infiltration dynamics in block cave mining are critical to understanding and managing inrush hazards that threaten mine safety and operational continuity. Primary water sources, groundwater aquifers, water-bearing faults, and surface water entering through the subsidence crater interact within the cave muck pile through preferential flow pathways that develop and evolve during mining. How that water then partitions within the broken ore column has received less attention. This research investigates the development and flow behaviour of these pathways using an integrated physical and numerical modelling approach. A conceptual model of a draw column is proposed and tested, characterized by central compressive plug flow zones (PFZ) bounded by finer-grained shear bands (SB1, SB2) that respond differently under unsaturated and saturated conditions. A 76-day quasi-two-dimensional physical experiment, instrumented with seven dielectric moisture sensors and a continuous load-cell mass balance, was complemented by a continuum-flow simulation in MIN3P-HPC, providing an independent benchmark of the within-medium hydraulic behaviour. Grain-size distribution contrasts between the shear bands and plug-flow zones govern infiltration patterns more strongly than geometric position does. The fines-rich shear bands retain three to three-and-a-half times the moisture content of the surrounding plug flow zones across all applied flux conditions. Moisture accumulates by capillary imbibition, drawing water laterally from the PFZ into the fines and holding it against gravity drainage on operationally relevant timescales. Sensor integration and continuum simulation give consistent end-of-experiment within-medium storage of 10.5-11.7 L and 11.75 L, respectively. The simulation also identifies the highest moisture contents along the drawbell walls, flanking the drawpoints, a zone too thin to be resolved by the sensors but implicated as the mechanically weakest plane in the draw column during extraction. No positive pore pressures developed under the conditions tested. In real caves, larger blocks of low-permeability material can act as capillary breaks above which positive pore pressures may develop locally (Pruess, 1999); this was outside the scope here. These insights advance mechanistic predictive models of inrush hazard susceptibility and support effective risk management in block-cave mines.
Arezo Ibrahimi (Fri,) studied this question.