INTMA Ltd (Moscow, Russia):
Safronov P. A., Head of Automation Department.
Tsoraev V. T., Control Equipment Leading Engineer, micon@yandex.ru

The article covers the main issues of concern in the field of ore grinding automation in processes with circulating material flows. An approach to automation of an ore grinding process line is proposed, based on the use of computational methods for determining current values of such process parameters that may not be directly measured using existing continuous monitoring equipment. Especially relevant are the computational methods for determining the flow characteristics of the circulating load and the discharge density for mills operating in a closed loop with screw-type classifiers and hydrocyclones. The calculation of directly non-measurable solid phase flow rates for two-phase flows may be based on measurements of the mass fraction of solids in the two-phase flow or on measurements of the flow rates of single-phase process water flows fed to the process. The approach with the measurement of single-phase process water flow rates is the most reliable. Real-time computation of the process parameters enables implementation of the combined control principle at the level of local circuits, under which the simple proportional deviation method is combined with control by reference inputs. The article also covers a procedure for stabilizing sump slurry levels by controlling the capacity of the discharge pump by the method of successive approximations with correction by level sensor signals and with account of the current conditions. The most suitable types of measuring instruments are proposed for the actual implementation of the above approach to grinding process line automation at operating ore mining and processing facilities.

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