Multi-physics modelling and simulation on the spontaneous heating of sulfide ores

The spontaneous combustion of sulfide ore piles poses a significant threat to miners' health and mining safety. In this work, numerical simulations of the temperature, velocity, and concentration field during the self-heating of sulfide ore piles were conducted using COMSOL Multiphysics. A self-heating model was established based on porous media fluid dynamics and heat transfer theory. The simulation parameters were determined, and the numerical solution of the heat conduction equation for sulfide ores was obtained. The results indicate a three-stage temperature progression: slow oxidation (0–10 days, with temperatures below 335 K), rapid heating (10–16 days, with a peak temperature of 926 K), and gradual cooling (16–24 days). The stacking method significantly influences the self-heating temperature field. Larger cross-sectional areas, stack heights, and stack angles of ore piles lead to higher temperatures and shorter safe stacking times. Furthermore, the lower the porosity and the slower the ambient wind velocity, the greater the risk of spontaneous combustion in a stockpile due to heat accumulation. This work can provide a predictive framework for optimizing ore pile geometry and ventilation strategies, offering practical insights to mitigate spontaneous combustion risks in mining operations.