Limited data on the behavior of impurity elements during the formation of ore minerals in hydrothermal systems reduce their potential as indicators of the physicochemical conditions of ore formation. One of the most common sulfides capable of concentrating precious metals and other valuable components is pyrite. The distribution of a number of typomorphic impurity elements in pyrite under its crystallization in hydrothermal conditions at a temperature of 450 °C and a pressure of 1 kbar was studied. Using X-ray spectral microanalysis, scanning electron microscopy, and inductively coupled plasma and laser ablation mass spectrometry, data were obtained on the forms of occurrence, content ratios, and correlation relationships of impurity elements in the volume and surface layer of pyrite crystals. For the first time, the parameter S of surface phase selectivity with respect to main (Co, Cu, Ni) and minor impurities (noble metals, As, Zn, Mn) was determined, which averaged 1.9 (Co), 2.1 (Cu), 1.3 (Ni), 4.2 (Pd), 18.5 (Au), 6 (As), 10.2 (Zn), and 9.1 (Mn). The correlations between elements are significantly different for the surface and volume, which is explained by the influence of surface phase selectivity. The dual nature of the correlation between Au and As allows their relationship to be considered a surface phenomenon. Palladium, a critically important metal widely used in chemical catalysis and other areas of technology, exhibits unusual behavior in pyrite, concentrating mainly on its surface, which suggests the possibility of its concurrent extraction from pyrite ores at gold extraction enterprises. The observed correlations are considered from the perspective of the incorporation of impurity elements into the bulk structure of pyrite and into the compositions of surface phase-like formations (non-autonomous phases) that evolve during crystal growth and are enriched with incompatible elements.

Controlling the ventilation in underground mining enterprises (UME), characterized by high inertia and numerous influencing external factors, based on real-time sensor data located in mine workings and on the surface, with a high level of accuracy in regulating air supply by the main ventilation unit (MVU), is feasible only under conditions of a pre-defined sequence of control actions. This task can be classified as an approximate dynamic programming (ADP) problem, which involves synthesizing a suboptimal control function for MVU operation in a predictive modeling mode of air distribution, given a known space of possible states and the selection of the optimal control strategy that meets a specified criterion. A simulation model of a digital twin subsystem for ventilation process control is presented, using the example of two types of UME (potash mines and oil shafts), which can be used to solve ADP tasks. For predictive modeling of air distribution and determining the energy efficiency criterion of the MVU, which consumes up to half of the total electricity of the UME, the digital twin is integrated with external data, based on which energy consumption is evaluated while maintaining the required volume of supplied air. This control approach enables not only safe and energy-efficient management of the ventilation process but also participation in the planning and implementation of measures for price-dependent electricity demand management.

The article considers a cybernetic model for the price-dependent demand response (DR) consumed by an underground mining enterprise (UGME), in particular, the main fan unit (MFU). A scheme of the model for managing the energy consumption of a MFU in the DR mode and the implementation of the cybernetic approach to the DR based on the IoT platform are proposed. The main functional requirements and the algorithm of the platform operation are described, the interaction of the platform with the UGME digital model simulator, on which the processes associated with the implementation of the technological process of ventilation and electricity demand response will be simulated in advance, is shown. The results of modeling the reduction in the load on the MFU of a mining enterprise for the day ahead are given. The presented solution makes it possible to determine in advance the necessary power consumption for the operation of the main power supply unit, manage its operation in an energy-saving mode and take into account the predicted changes in the planned one (e.g., when men hoisting along an air shaft) and unscheduled (e.g., when changing outdoor air parameters) modes. The results of the study can be used to reduce the cost of UGME without compromising the safety of technological processes, both through the implementation of energy-saving technical, technological or other measures, and with the participation of enterprises in the DR market. The proposed model ensures a guaranteed receipt of financial compensation for the UGME due to a reasonable change in the power consumption profile of the MFU during the hours of high demand for electricity, set by the system operator of the Unified Energy System.

Prospects of application of STATCOM in the power supply system of metallurgical enterprises consist in the use of its dynamic qualities in voltage maintenance and the possibility of working as an active filter of higher harmonics created by extraneous sources.