Ukhta State Technical University, Ukhta, Russia:

A. F. Galkin, Professor, Doctor of Engineering Sciences, afgalkin@mail.ru
I. V. Kurta, Associate Professor, Candidate of Engineering Sciences

Ammosov North-Eastern Federal University, Yakutsk, Russia:
V. Yu. Pankov, Associate Professor, Candidate of Geologo-Mineralogical Sciences

Some features of the operation of gold mines in the permafrost zone under unregulated thermal conditions are analyzed. It is shown that on some days in winter, the temperature on the working horizons in mines may fall below the liming temperatures set by the criterion of safe operation of personal protective equipment (self-rescuers) for the respiratory organs of underground miners. For the self-rescuers most widely used in ore mining, this temperature is minus 20 °C. One of the ways out of this situation is temporary abandonment of a mine, which, according to design experts, is economically viable, for example, compared to heating of air supplied to the mine in the winter period. The purpose of this work is to estimate duration of temporary abandonment, which is necessary to calculate the annual design capacity and the length of the field development period. A simple engineering method is proposed for calculating the temporary abandonment period of a mine in the winter period at extremely low outdoor temperatures. The method is based on solving the heat balance equation for a section of the ventilation network from the beginning of air supply to the control point, which is assumed to be the distance from the mouth of the air supply to the point where the temperature in the coldest month of the year (January) is not less than minus 20 °C. Test calculations have been performed for the projected mines Vetrensky (Magadan Region) and Sentachan (Republic of Sakha (Yakutia)), the climatic conditions of which can be considered typical. On the basis of multivariate calculations from the proposed formulas, it has been found that for the characteristic climatic conditions of ore deposits in the permafrost area, the duration of the temporary abandonment period, as a rule, is not longer than three weeks. The most likely value is a period of 10–15 days.

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