Computer Control of Vuonos Mine

Abstract

The Vuonos mine of Outokumpu Oy in eastern Finland was the first mine to go on-stream with computer control. Production of low grade nickel ore started in the beginning of 1972 and that of copper ore at the end of the same year. A process control computer was used at the start-up. The entire system of instrumentation and automation is based on direct digital control, the planning being carried out with the help of experiences from computer control of the Pyhäsalmi mine and pyrite flash smelting process at Kokkola. In several cases manual back-up facilities are minimized in order to reduce the cost of the total automation system. The total number of control loops is over 200 and the number of measured and calculated variables is over 500.

The computer control system covers the whole process from hoisting to dewatering. The functions of the computer include sequence control of hoisting and crushing, direct digital and supervisory control of grinding as well as flotation and dewatering processes. Other important features of the system are high level reporting to plant management and facilities for process studies. A special program system has been built in order to develop mathematical models for optimizing control.

Valuable experience has been gained in starting the plant under computer control. The computer system has been in continuous operation and has proved indispensable in managing the complicated operations and control functions at the Vuonos mine.