Numerical modeling of pore-fluid flow and heat transfer in the Fushan iron ore district, Hebei, China: Implications for hydrothermal mineralization

• Fluid velocity variations influence the probability of mineralization.
• The coupled thermo-hydrological process of Fushan district mineralization is modelled.
• Mineralization is associated with abrupt temperature drop.
• Temperature has significant effects on the magnetite equilibrium concentration within a range of 300 °C and 450 °C.

This paper uses the numerical method to simulate pore-fluid flow and heat transfer associated with iron ore-forming processes in the Fushan iron ore district, Hebei, China. Since mineralization may last a long period of time in a hydrothermal system, it is commonly assumed, in geochemistry, that the solutions and minerals are in an equilibrium state or near an equilibrium state. The relationship between the equilibrium concentration of iron and temperature has been considered to determine the mineralization rate of iron ore. Using the FISH language in the FLAC code, the coupled pore-fluid flow, heat transfer and mineralization have been simulated first with a generic model, and then with an actual geological model of the Fushan iron ore district. Since the equilibrium concentration of iron ion (Fe2 +) in magnetite (in the NaCl buffer) has been calculated using the TOUGHREACT software in geochemistry, it can be used to analyze the precipitation pattern of magnetite. The results of hydrothermal studies of coupled heat transfer and pore fluid flow with considering the mineralization rate can enhance our understanding of the ore formation processes in the Fushan district, and can be used directly or indirectly for mineral exploration.