Accurate characterisation of ore competence through controlled single particle impact can enable improved modelling of comminution process response to ore variability. A simple relationship is presented to relate the energy input and feed particle size to the breakage progeny with two fitting parameters. Previous techniques have focused either on low energy repeated impacts or high energy single impacts and have been applied over relatively small ranges of particle sizes. The method presented builds on previous understanding to unite these two disparate fields on feed particle sizes over more than two orders of magnitude. The method has been tested on 5 ores from 37.5 mm to 250 pm over energies from 0.02 to 3.5 kWh/t. The resultant standard error of 33% is lower than other benchmarked models, with considerably fewer fitting parameters and no use of splining functions required. The direct calculation of appearance function for any feed size and input energy renders the proposed model well suited to incorporation in comminution process models. Further testing is required on additional ores, and further interpretation is required to obtain mechanistic explanations for the empirical fits to the model parameters. (C) 2017 Elsevier B.V. All rights reserved.