Heap leach pads are common in the mining industry. Their design and management commonly do not consider criteria based on coupled hydrogeomechanical-geochemical processes. However, these are of utmost importance for two main reasons: (1) they could play an important role in the physical stability of the pad; and (2) they are fundamental for metallurgical efficiency, especially in the medium and long term. As an example of the relevance of complex coupled phenomena, it can be mentioned that the geotechnical stability of the heap is related to the distribution of liquid pressures which, in turn, is related to permeability through Darcy’s law. In turn, the permeability will be affected by changes in porosity, which depend on the state of consolidation and the dissolution/precipitation of minerals. Obviously, the hydrometallurgical performance of the heap ore is also strongly related to the coupled processes mentioned above. In this work, we present a numerical model to solve the coupled hydro-geomechanical-geochemical processes, developed with COMSOL-PHREEQC, a Java interface developed to combine COMSOL Multiphysics, a well-known commercial FEM platform, with PHREEQC, the open-source geochemical simulator developed at USGS and used worldwide. The resulting numerical tool is capable of simultaneously solving unsaturated liquid flow, effective soil stress, and geochemical dissolution and precipitation of HEAP LEACHING SOLUTIONS, 2014 274  LIMA, PERU. Geochemical changes affecting porosity and permeability are explicitly coupled in hydraulic and geomechanical calculations.