Computational simulation of iron ore-forming processes in the Caiyuanzi siderite ore district, Guizhou, China

• Pore-fluid pressure variation has little influence on the siderite mineralization.
• The coupled thermo-hydrological process of Caiyuanzi district mineralization is simulated.
• The mineralization is associated with the sedimentary environment of the carbonate layer.
• Temperature has significant effects on the siderite equilibrium concentration within a range of 125 °C and 275 °C.

By means of 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 in the Caiyuanzi siderite ore district, Guizhou. The effect of pore-fluid pressure on the equilibrium concentration of siderite has been considered. The main purposes of this paper are: (1) to illustrate some simulation results for the possibility of hydrothermal mineralization of siderite in a sedimentary environment; (2) to get a better understanding of the processes and mechanism of siderite orebody formation in the sedimentary environment; (3) to analyze the influence of the concentration of carbon dioxide on the siderite mineralization; and (4) to compare the simulation results with the actual situation, so as to demonstrate that this simulation method is effective and feasible for understanding the mineralization mechanism of iron ore in the Caiyuanzi siderite ore district.