Overlapping uranium and coal resources are widely distributed in the basins of China. The current uranium–coal coordinated mining model, mining interaction, and multi-phase and multi-field coupling mechanisms remain unclear, thereby substantially restricting the mining of overlapping uranium and coal resources. This article reviews the overlapping uranium–coal mining technology and conditions, summarizes the main problems faced by the coordinated mining of coexisting uranium–coal resources, proposes a dynamic coordinated mining technology system for the entire life cycle of coexisting uranium–coal resources, and describes the multiphase and multifield coordinated mining of co-associated uranium–coal resources. The multifield coupling mechanism clarifies the solid–liquid–gas three-phase spatiotemporal coupling effects of the stress, fracture, seepage, geochemical, pressure, and microbial fields, and explains the safe and efficient mining technology of uranium and coal resources, and the coordinated mining and isolation technology of uranium and coal. “Trinity” pollution prevention and control technology and other key research directions are discussed to promote green, efficient, joint, and coordinated mining of uranium and coal.

The coordinate mining of stack resources in the Ordos Basin, which involves the coupling effects of stress fracture, seepage, and reactive solute transport, plays an important role in resource exploration and environment protection. A coupled multiphysical–chemical model, involving a modified non-Darcy flow model, a leaching solution reaction, and a reactive solute transport model, was developed in this study. The Fast Lagrangian Analysis of Continua -Computational Fluid Dynamics (FLAC3D-CFD) simulator coupled with the developed models was used to investigate the evolution and morphology of mining-induced multifield coupling for the scenarios of concurrent mining and asynchronous mining of coal and uranium. As mining advanced to 160 m, the maximum principle stress characterized by a stress shell was observed. As mining progressed to 280 m, a rupture occurred, and a new stress shell was generated as a rear skewback was formed by the concentrated stress of the stope. An “arch-shaped” fracture field combined with a “saddle-shaped” seepage field was identified in the destressed zone of the stress shell. In the coordinated mining of uranium prior to coal, “funnel-shaped” and “asymmetric saddle-shaped” morphologies of the leaching solution were found during coal mining for ventilation in the stope and mining face. By contrast, “saddle-shaped”, “inclined funnel-shaped”, and “horizontal” morphologies of the leaching solution were observed for a short period for ventilation of the stope and mining face for coal mining prior to uranium mining, uranium mining prior to coal mining, and synchronized coal and uranium mining. A dynamic stress response was obtained in the coal seam, followed by the conglomerate aquifer and the uranium deposits. The diffusion depth of the solution was negatively correlated with the injection velocity and the pumping ratio and positively correlated with the diffusion coefficient. A dynamic increase in diffusion depth was observed as the diffusion coefficient increased to 1 × 10⁻⁴ m²/s.

The reactive-transportation of radioactive elements in fractured rock mass is critical to the storage of radioactive elements. To describe the reactive-transportation and distribution morphology of a uranium-containing solution, a stress-dependent reactive transport model was developed, and the simulator of FLAC3D-CFD was employed. The uranium transport experiment subjected to the variation of confining stress of 5–19 MPa and hydraulic pressure of 0.5–3.5 MPa was conducted in fractured rock mass. The results show that the uranium-containing solution transport and distribution is significantly dependent on the evolution of the connected channel in rough-walled fracture, which is significantly influenced by the confining stress and hydraulic pressure. In more detail, the increase of confining stress resulted in the anisotropic of seepage channel in aperture, and corresponding turbulence flow and uranium retention were presented at the fracture aperture of 2–5 μm. As the increase of hydraulic pressure, flow regime evolved from the inertial flow to vortex flow, and the transformation region is 16 MPa confining stress and 1.5 MPa hydraulic pressure. The evolution of loading paths also dominates the flow and solute transport, and high seepage speed and strong solute transport were presented at the k = 1 (ratio of vertical stress loading to horizontal stress unloading), and a laminar flow and weak solute transport were presented at k = 0.

The fluid flow in underground reservoirs is directly related to resource recovery and hazard prevention. In this study, the evolution of fractured sandstone deformation and permeability under an in situ stress influence is investigated using the true triaxial percolation system. The results show that the strain of fractured sandstone increases logarithmically with the increase in axial stress. The evolution of axial strain is dominated by the maximum principal stress, and the minimum principal stress and the intermediate principal stress affect the strain amplitude. The fracture morphology of low-permeability sandstone affects permeability and strain evolution. Small fractures are more sensitive to the increase in the maximum principal stress, and the response in principal strain to the increase in principal stress is obvious in large fractures. There is a negative exponential relationship between pore pressure and the conductivity of fractures. When pore pressure is 0.3 MPa, the conductivity is the highest; meanwhile, when pore pressure is 1.8 MPa, the conductivity is the lowest. The decreasing range of the conductivity increases with the increase in fracture size. In situ stress significantly affects the evolution of principal strain and related permeability. The permeability decreases with an increase in the minimum and middle principal stresses. Under low pore pressure (0.3–0.6 MPa), the permeability decreases with an increase in the principal stress; meanwhile, under high pore pressure (0.6–1.8 MPa), permeability changes slightly with an increase in the principal stress. The findings provide reference to the engineering practice of underground mining.