Öz Process control computers, which were first introduced in 1959, are now being applied at a rapidly increasing rate. A recent survey showed 2890 installations: an increase of 1319 over the previous survey approximately a year earlier. With the additional availability of on-line X - ray analysis instrumentation experience is now being gained with initial mining industry applications such as grinding and flotation. Following an outline of automatic control, process computer and instrumentation techniques, a discussion is presented on computer control systems for mineral concentrating plants. Progress on computer control in the mining industry is now expected to be made more rapidly than in the past because of the carry-over ofsystems knowledge gained from applications in other industries such as steel, chemical, petroleum and electric utilities.