An integrated mine geothermal extraction and cooling system based on the holistic space utilization concept of mine

Deep mines often encounter heat hazards due to high surrounding rock temperatures, yet this heat can be harnessed as geothermal energy, leading to the concept of Synergetic mining of mine geothermal energy (SMGE). However, previous studies have only focused on geothermal extraction at single-depth levels and have not fully utilized existing mine facilities. Consequently, this paper proposes an integrated Mine Geothermal Extraction and Cooling System (MGECS) that combines heat hazard control with geothermal extraction from a whole-mine perspective. A calculation method for the Thermal-hydraulic-ventilation (THV) coupling effect is presented, overcoming the limitation of previous models by incorporating roadway temperatures. The study includes 2 system layouts, 4 base cases, and 12 working conditions. Results indicate that under normal conditions, the vertical well layout outperforms the horizontal well layout in cooling effect, heat extraction, and cooling stability. However, under high geothermal gradients, the horizontal well layout can surpass the vertical well layout in heat extraction. When designing the injection scheme for the system, it is advisable to use lower injection volumes and temperatures to enhance cooling and sustainable heat extraction. Increasing fracture permeability and thickness can boost geothermal extraction but may reduce the system's cooling efficiency.