Abstract To address the problem of aquitard damage and cross-strata radon migration induced by the mining of underlying coal seams under conditions of coal-uranium overlapping strata, a coupled stress-damage-seepage-mass transport model was established. The damage evolution was qualitatively verified through similar simulation experiments. On this basis, a three-dimensional stratigraphic model was developed according to the actual geological structure of a uranium mining area. The evolution characteristics of surrounding rock stress, displacement, damage, permeability, and the spatiotemporal distribution of radon in the strata and around the coal mining area were systematically analyzed under different mining distances. The results indicate that coal mining disturbance causes the damage in the overlying strata to continuously propagate upward, leading to a reduction in the local integrity of the aquitard and an increase in the permeability of the damaged zone by up to two orders of magnitude. Deflection of the flow field further promotes the migration of radon-bearing groundwater toward the coal mining area along high-permeability pathways. After 72 months, radon penetrates the aquitard and enters the coal mining area, resulting in a significant increase in concentration. The average radon concentration in the coal mining area reaches its peak at 140 months and gradually stabilizes after 170 months. This study reveals the evolution of cross-strata radon migration under mining-induced damage control.
He et al. (Wed,) studied this question.