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Mikhail A. Semin
Mikhail A. Semin
Researcher, Ph.D.
Mining Institute of the Ural Branch of the Russian Academy of Sciences
Perm Russia
Researcher, Ph.D.
Mining Institute of the Ural Branch of the Russian Academy of Sciences
Perm
Russia
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Articles

  • Date submitted
    2020-05-26
  • Date accepted
    2020-09-23
  • Date published
    2020-12-25

Automated ventilation control in mines. Challenges, state of the art, areas for improvement

The article is divided into three main parts. The first part provides an overview of the existing literature on theoretical methods for calculating the optimal air distribution in mines according to the criteria of energy efficiency and providing all sections of mines with the required amount of air. It is shown that by the current moment there are many different formulations of the problem of searching the optimal air distribution, many different approaches and methods for optimizing air distribution have been developed. The case of a single (main) fan is most fully investigated, while for many fans a number of issues still remain unresolved. The second part is devoted to the review of existing methods and examples of the automated mine ventilation control systems implementation in Russia and abroad. Two of the most well-known concepts for the development of such systems are automated ventilation control systems (AVCS) in Russia and the CIS countries and Ventilation on demand (VOD) abroad. The main strategies of ventilation management in the framework of the AVCS and VOD concepts are described and also the key differences between them are shown. One of the key differences between AVCS and VOD today is the automatic determination of the operation parameters of fan units and ventilation doors using the optimal control algorithm, which is an integral part of the AVCS. The third part of the article describes the optimal control algorithm developed by the team of the Mining Institute of the Ural Branch of the Russian Academy of Sciences with the participation of the authors of the article. In this algorithm, the search for optimal air distribution is carried out by the system in a fully automated mode in real time using algorithms programmed into the microcontrollers of fans and ventilation doors. Minimization of energy consumption is achieved due to the most efficient selection of the fan speed and the rate of ventilation doors opening and also due to the air distribution shift control and the partial air recirculation systems introduction. It is noted that currently the available literature poorly covers the issue related to emergency operation modes ventilation systems of mines and also with the adaptation of automated control systems to different mining methods. According to the authors, further development of automated ventilation control systems should be carried out, in particular, in these two areas.

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Mikhail A. Semin, Evgenii L. Grishin, Lev Yu. Levin, Artem V. Zaitsev (2020) Automated ventilation control in mines. Challenges, state of the art, areas for improvement. Journal of Mining Institute. Vol 246. p. 623-632. DOI: 10.31897/PMI.2020.6.4
  • Date submitted
    2020-05-26
  • Date accepted
    2020-06-10
  • Date published
    2020-06-30

Theoretical analysis of frozen wall dynamics during transition to ice holding stage

Series of calculations for the artificial freezing of the rock mass during construction of mineshafts for the conditions of a potash mine in development was carried out. Numerical solution was obtained through the finite element method using ANSYS software package. Numerical dependencies of frozen wall thickness on time in the ice growing stage and ice holding stage are obtained for two layers of the rock mass with different thermophysical properties. External and internal ice wall boundaries were calculated in two ways: by the actual freezing temperature of pore water and by the temperature of –8 °С, at which laboratory measurements of frozen rocks' strength were carried out. Normal operation mode of the freezing station, as well as the emergency mode, associated with the failure of one of the freezing columns, are considered. Dependence of a decrease in frozen wall thickness in the ice holding stage on the duration of the ice growing stage was studied. It was determined that in emergency operation mode of the freezing system, frozen wall thickness by the –8 °C isotherm can decrease by more than 1.5 m. In this case frozen wall thickness by the isotherm of actual freezing of water almost always maintains positive dynamics. It is shown that when analyzing frozen wall thickness using the isotherm of actual freezing of pore water, it is not possible to assess the danger of emergency situations associated with the failure of freezing columns.

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Mikhail A. Semin, Lev Yu. Levin, Aleksandr V. Bogomyagkov (2020) Theoretical analysis of frozen wall dynamics during transition to ice holding stage. Journal of Mining Institute. Vol 243. p. 319. DOI: 10.31897/pmi.2020.3.319