A methodology was developed in the mid-1980s to predict plant performance from standard laboratory flotation tests. The technique is based on a simple, empirical kinetics model, and is tailored for use by the practical metallurgist. To date the performance of more than 20 flotation plants has been predicted, encompassing copper, lead, zinc, nickel, phosphate, pyrite, graphite, cassiterite, platinum and various slags. The method has successfully been used to predict and design four flotation plants using data generated from bench-scale laboratory flotation testwork. All have since been commissioned, and have performed as predicted. The technique has now received broad acceptance within the South African mining industry, for example in the last year alone it has been used to drive flowsheet development for seven new plants. It is also being used to assist in the optimisation of existing operating plants. The methodology is described in this paper. Also, verification of the methodology is presented using a number of case studies. (C) 2003 Elsevier Ltd. All rights reserved.