Heap leaching is a process extensively used by the mining industry to recover metals from large quantities of submarginal material resources. Understanding flow through a packed particle bed is important to enhance the performance of heap leaching with respect to design and operating considerations. The microstructure and connectivity of pore space are important features to describe detailed fluid flow phenomena in heap leaching operations. In this regard, a milli-CT scanner was used to determine the complex pore structure of a packed column before and after bioleaching of copper ore. The 3-D reconstructed images of complex pore structures obtained from the milli-CT scans were used for the analysis of saturated flow inside the leaching column based on lattice-Boltzmann (LB) simulations. (c) 2005 Elsevier Ltd. All rights reserved.