In the monograph, a number of problems of scientific and technical importance are introduced and discussed, which are of great interest, and can find widespread application in the circles of engineers and researchers, as well as graduate and post-graduate students engaged in investigation, optimisation and management of electromechanical systems. The theoretical and practical results presented in the work have applied significance for investigating, optimising, revealing the regularities of changing the operation modes, establishing the technological factors and power dependencies, controlling the operating state of the elastic transmission links of the electromechanical system, and, based on them, developing a control system for the diagnosis tool of the system's operating state and increasing the power consumption efficiency. The methods introduced in the monograph differ from those developed by other well-known authors in that the author has succeeded in revealing the relationship of technological and energetic parameters. Taking into consideration the variety of the technological load, mechanisms and schemes, the author has proposed and implemented new complex approaches to making optimal decisions on the problem, considering them in the solution of diverse problems aimed at increasing the efficiency of the ore-grinding technological process. In Chapter 1 of the monograph, the principles of increasing the control efficiency of the ore-grinding technological process by assessing the power-saving possibilities for the consumed energy have been considered. In Chapter 2, the operation modes of the ore mill have been investigated, for which models for investigating the change in the moment of the active load and the mill -- motor electromechanical system have been developed. A system of criteria for studying the changes in the grinding degree, time, and the number of mills used has been obtained, and the condition for the stability of the gravity centre of the mill active load, as well as the frequency areas of interest for assessing the state of the system have been revealed. Chapter 3 is devoted to the development of the imitation model for investigating the dynamic processes of the electrical drive systems ensuring the ore mill operation, which reveals the regularities of changes in the electromagnetic torque and dynamic load at different characteristics of changes in the resistive torque created by the mill, and at different values of hardness of the drive unit. In Chapter 4, the possibilities of identifying and preventing abnormal operating modes of synchronous electrical drive of the ore-grinding mill are considered. In Chapter 5, the optimisation problem is formulated through the analysis of the grinding control strategy and energy-saving requirements. The necessity of forming a loss matrix to determine the optimisation criteria and controlled parameters is substantiated. In Chapter 6, the automated diagnosis and control systems are proposed that provide wide control possibilities, and, in the last chapter, method of rationing the specific consumption of electricity by the technological process of grinding is presented.