To obtain an extensive understanding of the behavior of the key parameters in grinding processes, factorial design is applied to a ball mill test using four variables, each at three levels. This required a total of 27 tests. The influence of charge volume, mill speed, feed and pulp density on grinding fineness and net energy consumption were related and in order by multiple regression analysis. The computer-based response surfaces of the dependent variables demonstrated the combined effects of the operational parameters. They also provided a base for further tests on the multiple influence of the process variables on continuous grinding.