<p>Iron and manganese ore production plays a critical role in sustaining global development. However, the drying of these materials and the heat and mass transfer mechanisms involved in the process remain underexplored. This paper presents and compares drying behavior of iron and manganese ores in thin and thick fixed bed layers, identifying the main heat and mass transfer mechanisms, determining the associated mass transfer coefficients and effective diffusivities. Wet ores were dried in a thin-layer bed of 1&#xa0;cm thickness at temperatures of 50, 60, 70, and 80&#xa0;°C and an inlet air velocity of 0.7&#xa0;m·s⁻¹. In the thick bed experiments, temperature and moisture were locally measured at 10 axial positions along the porous medium. Additionally, the average moisture was determined. Results showed that thin-layer drying occurred during the falling rate period for both ores. Effective diffusivity values obtained for iron ore drying ranged from 1.51 × 10^–9 to 5.55 × 10^–9 m²·s⁻¹, while for manganese ore the values ranged between 1.45 × 10^–9 to 2.51 × 10^–9 m²·s⁻¹. Thick-layer experiments indicated moisture and temperature gradients along the axial position. Comparing both mineral materials, results also indicated that the drying process occurs faster and with less heterogeneity for the iron ore.</p>