Since the first experiments with computerized expert control of grinding plants in the early 1970’s expert control has steadily progressed in the minerals industry to be very advanced, including not only many artificial intelligence methodologies but advanced computing and measurement systems. A 1970’s expert system will be compared with the latest systems used in the industry along with performance comparisons. The most advanced systems today use real time image systems as well as acoustic systems that listen to the grinding process within the mill to further understand the process of grinding in large mills.