Two aspects of the computer simulation of minerals processing systems were investigated in order to facilitate more effective use of simulation technology. A user-interface was designed and combined with an existing simulator executive, resulting in the implementation of a user-friendly microcomputer based minerals processing simulator, MicroSim. Ease of use was achieved by consideration of the needs of the user of such a program. This resulted in the use of graphical methods for information input and output. Efficient form-filling techniques were developed for numerical data entry and editing. Models for the carbon-in-pulp adsorption process and for continuous gold leaching were derived. The CIP models were derived using a population balance approach. The method of characteristics and the method of moments were found to be particularly useful in solving the resulting equations. Besides being important processes in themselves, the integration of these models into MicroSim provided valuable experience regarding the use of such models in a simulator. / AC 2016